OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

SIDS Initial Assessment Report

For

SIAM 20

Paris, France, 19-22 April 2005

1. Chemical Name: 4,4 ́-Methylenedicyclohexyl diisocyanate

2. CAS Number: 5124-30-1

3. Sponsor Country: Contact Point: 

BMU (Bundesministerium für Umwelt, Naturschutz und

Reaktorsicherheit)

Contact person:

Prof. Dr. Ulrich Schlottmann

Postfach 12 06 29

D- 53048 Bonn

4. Shared Partnership with: -

5. Roles/Responsibilities of

the Partners:

-

• Name of industry sponsor

/consortium

Bayer AG, Germany

Contact person:

Dr. Burkhardt Stock

D-51368 Leverkusen

Gebäude 9115

• Process used OECD/ICCA - The BUA Peer Review Process: see next page

6. Sponsorship History

• How was the chemical or

category brought into the

OECD HPV Chemicals

Programme ?

by ICCA-Initiative

7. Review Process Prior to

the SIAM:

last literature search (update):

4 October 2004 (Human Health): databases medline, toxline; search

profile CAS-No. and special search terms

8 November 2004 (Ecotoxicology): databases CA, biosis; search

profile CAS-No. and special search terms OECD/ICCA

8. Quality check process: IUCLID was used as a basis for the SIDS dossier. All data were

checked and validated by BUA. A final evaluation of the human

health part has been performed by the Federal Institute for Risk

Assessment (BfR) and of the ecotoxicological part by the Federal

Environment Agency (UBA).

9. Date of Submission: Deadline for circulation: 21 January 2005

10. Date of last Update: Last literature search: IUCLID Chapters 1-4: 2003-08-13, Chapter

3.2.1 2004-07-27, Chapter 5: 2003-01-22; 

1
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

11. Comments: OECD/ICCA - The BUA* Peer Review Process

Qualified BUA personnel (toxicologists, ecotoxicologists)

perform a quality control on the full SIDS dossier submitted by

industry. This quality control process follows internal BUA

guidelines/instructions for the OECD/ICCA peer review

process and includes:

• a full (or update) literature search to verify completeness of

data provided by industry in the IUCLID/HEDSET

• Review of data and assessment of the quality of data

• Review of data evaluation

• Check of adequacy of selection process for key studies for

OECD endpoints, and, where relevant, for non-OECD

endpoints by checking original reports/publications

• Review of key study description according robust

summaries requirements; completeness and correctness is

checked against original reports/publications

(if original reports are missing: reliability (4), i.e.

reliability not assignable)

• Review o f validity of structure-activity relationships

• Review of full SIDS dossier (including SIAR, SIAP and

proposal for conclusion and recommendation for further

work)

• In case of data gaps, review of testing plan or rationale for

not testing

* BUA (GDCh-Beratergremium für Altstoffe): Advisory Committee on Existing Chemicals of the Association of

German Chemists (GDCh)

2
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

SIDS INITIAL ASSESSMENT PROFILE

CAS No. 5124-30-1

Chemical Name 4,4 ́-Methylenedicyclohexyl diisocyanate

Structural Formula

N

C

O

N

C

O

SUMMARY CONCLUSIONS OF THE SIAR

Human Health

4,4 ́-Methylenedicyclohexyl diisocyanate is of low oral and dermal acute toxicity with an oral LD50 (rat) of

9900 mg/kg bw and a dermal LD50 (rabbit) > 10,000 mg/kg. Toxic symptoms after oral administration included

severe diarrhea, loss of appetite and increasing weakness. Assessment of the acute inhalation toxicity data

indicates that exposure to respirable aerosols of 4,4 ́-methylenedicyclohexyl diisocyanate confined predominantly

to the respiratory tract. Clinical signs (salivation, bradypnea, stridor) indicated respiratory distress. A

haemorrhagic lung edema was considered to be causative for mortality. An animal study according to

OECD TG 403 gives a LC50 (4 h, rat) of 434 mg/m3.

4,4 ́-Methylenedicyclohexyl diisocyanate is moderately to severely irritant to the skin of rabbits (OECD TG 404).

Irritant effects were observed after instillation of 4,4 ́-methylenedicyclohexyl diisocyanate into the eyes of rabbits

(OECD TG 405). The repeated dose studies indicate that 4,4 ́-methylenedicyclohexyl diisocyanate causes

irritation of the respiratory tract.

Animal data are not uniform however they frequently provide evidence of a skin sensitizing potential of 4,4

 ́-methylenedicyclohexyl diisocyanate. Human case reports describe allergic contact dermatitis due to 4,4

 ́-methylenedicyclohexyl diisocyanate exposure. Although no validated animal model is available to assess the

potential for respiratory sensitization or asthma in humans animal data support to some extent the hypothesis that

respiratory hypersensitivity may be induced by 4,4 ́-methylenedicyclohexyl diisocyanate. 

No results from repeated-dose toxicity tests are available for the oral and dermal route of exposure. A subacute

inhalation study (1, 6 and 36 mg/m3; 6 hours/day on five days/week for 4 weeks) with rats (OECD TG 412)

indicates the respiratory tract to be the target organ of respirable 4,4 ́-methylenedicyclohexyl diisocyanate aerosol.

The reported NOAEL for effects governed by respiratory tract irritation is 1 mg/m3; the LOAEL is 6 mg/m3(i.e.

histopathological changes in nasal passages, larynx and bronchi). The results of a reproduction/developmental

toxicity screening test (OECD TG 421) corresponds to the results of the subacute study.

4,4 ́-Methylenedicyclohexyl diisocyanate did not induce gene mutations in bacteria (OECD TG 471) and

demonstrated no potential to induce chromosome aberrations in Chinese hamster V79 cells in vitro

(OECD TG 473) either with or without metabolic activation.

Data from an inhalative reproduction/developmental toxicity screening test according to OECD TG 421 with rats

(1, 6 and 36 mg/m3) did not reveal substance related impairment of reproduction up to a 4,4

 ́-methylenedicyclohexyl diisocyanate concentration of 6 mg/m3. A slightly reduced fertility index was observed

at an exposure level (36 mg/m3) that was associated with parental toxicity. NOAELs were considered to be

1 mg/m3 in males and females for general toxicity. NOAEL for reproductive toxicity is 6 mg/m3.

Pre-natal inhalation toxicity testing in rats (OECD°TG°421) indicates the absence of selective toxicity to the

development at levels up to 36°mg/m3. No findings indicate any specific developmental effects such as live birth

index, viability index and apparent malformation. The reported NOAEL(developmental) for 4,4 ́-methylenedicyclohexyl

diisocyanate in a developmental toxicity study according to OECD TG 414 (1, 6 and 36 mg/m3) is 6 mg/m3/day.

At the 36 mg/m3level that caused clear maternal respiratory tract toxicity (NOAEL(maternal) = 1 mg/m3) increased

3
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

incidences of ventricular septal defects of the heart and slight dilation of lateral brain ventricles were observed,

which lay marginally above the upper or within the normal range of scattering of the rat strain used respectively.

Environment

4,4’-Methylenedicyclohexyl diisocyanate is a slightly yellowish, moisture/water sensitive liquid with a melting

point of 15 °C. 4,4’-Methylenedicyclohexyl diisocyanate has a relative density of 1.07 at 25 °C, a boiling point

of 167 - 168 °C (at 2 hPa), and a vapor pressure of 2.13 x 10-5 hPa at 25 °C [Directive 92/69/EEC, A.4]. A water

solubility and a log KOW are not determinable due to the instability of 4,4’-methylenedicyclohexyl diisocyanate in

water. The flash point of 4,4’-methylenedicyclohexyl diisocyanate is 200 °C [DIN 51758], the ignition point is

225 °C and the viscosity is approximately 30 mPa x s at 25 °C [DIN ISO EN 3219/A.3]. The calculated half-life

of 4,4’-methylenedicyclohexyl diisocyanate in air due to indirect photodegradation is about 15.0 h.

4,4’-Methylenedicyclohexyl diisocyanate hydrolyses rapidly in the presence of water, the major product in the

aqueous phase is methylene bis(4-cyclohexylamine). In water, a half-life for 4,4’-methylenedicyclohexyl

diisocyanate of approximately 2 hours was determined experimentally. Due to the rapid hydrolysis of

4,4’-methylenedicyclohexyl diisocyanate, a transport of the substance between environmental compartments is

unlikely. Consequently, a calculation of the Henry Law Constant and of the distribution between the

environmental compartments according to the Mackay fugacity model level 1 is not suitable.

However, several aquatic toxicity tests have been undertaken with 4,4’-methylenedicyclohexyl diisocyanate and

its hydrolysis products. Because of the rapid hydrolysis the assessment of the substance should be based on the

hydrolysis products and not on 4,4’-methylenedicyclohexyl diisocyanate. The hydrolysis product methylenebisp-cyclohexylamine was assessed by the EU PBT Working Group. The hydrolysis product was not classified as a

PBT substance.

4,4’-Methylenedicyclohexyl diisocyanate is not readily biodegradable.

Due to the rapid hydrolysis 4,4’-methylenedicyclohexyl diisocyanate is neither persistent in the water

compartment nor bioaccumulative. The calculated Koc-value indicates that 4,4’-methylenedicyclohexyl

diisocyanate may strongly adsorb to soil but due to its rapid hydrolysis any emission to the terrestrial

compartment would be affected by humidity and therefore, geoaccumulation of 4,4’-methylenedicyclohexyl

diisocyanate is not expected to occur.

Concerning the toxicity of 4,4’-methylenedicyclohexyl diisocyanate and its hydrolysis products towards aquatic

species, reliable experimental results of tests with fish, Daphnia, and algae are available (* = determined as TOC

and back-calculated to parent substance, n = nominal concentration).

Danio rerio (fish): 96 h-LC50 > 8.1 mg/l*, [Directive 92/69/EEC, C.1]

Daphnia magna (aq. invertebrate): 48 h-EC50 > 8.3 mg/l*, [Directive 92/69/EEC, C.2]

Scenedesmus subspicatus (algae): 72 h-ErC50 > 5 mg/l*, [Directive 92/69/EEC, C.3]

Activated sewage sludge (bacteria):3 h-EC50 = 191 mg/l (n), [Directive 88/302/EEC, Part C

(corresponds to the OECD TG 209)].

It has to be considered that the toxicity observed in the reported aquatic studies was caused both by the

4,4’-methylenedicyclohexyl diisocyanate as well as by the hydrolysis products due to the instability of the test

substance.

Based on the acute aquatic toxicity data on three trophic levels (fish, Daphnia, algae), the Predicted No Effect

Concentration (PNECaqua) can be calculated with an assessment factor of 1000 applied to the lowest acute effect

concentration. The lowest 72 h-ErC50-value of > 5 mg/l obtained for the alga species Scenedesmus subspicatus

was used to derive a PNECaqua of > 5 μg/l.

Exposure

Commercial 4,4’-methylenedicyclohexyl diisocyanate manufacturing starts with hydrogenated

methylenedianiline (methylenebis-p-cyclohexylamin) which is phosgenated. The global production capacity of

4,4’-methylenedicyclohexyl diisocyanate is 10 000 - 20 000 tonnes/a, with most of it in the USA. In Germany,

the only producer has a manufacturing capacity of 1000 - 5000 tonnes/a of 4,4’-methylenedicyclohexyl

diisocyanate.

4,4’-Methylenedicyclohexyl diisocyanate is an intermediate in the chemical industry, used for the manufacture of

binders or hardeners for coating materials or adhesives (60 %), prepolymers (20 %), and for other applications,

4
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

e.g. for the production of elastomers (20 %). 4,4’-Methylenedicyclohexyl diisocyanate is not used for “Do It

Yourself” applications or in other consumer products. 4,4’-Methylenedicyclohexyl diisocyanate is registered as a

component in approximately 50 industrial products listed in the Danish, Finnish, and Swedish Product Registers

with a consumption of about 30 tonnes/a in 2000 and 2001 (last years of record). 4,4’-Methylenedicyclohexyl

diisocyanate is confidentially listed in the Norwegian Product Register. There is no registration for a consumer

product. The main use category is “non-dispersive use”. For 4,4’-methylenedicyclohexyl diisocyanate the Swiss

Product Register lists 34 industrial products (with concentrations of up to 100 % 4,4’-methylenedicyclohexyl

diisocyanate), but no consumer product.

By the producer in Germany, 4,4’-methylenedicyclohexyl diisocyanate is manufactured and processed (including

filling) in closed systems at the same industrial site. To the customers most of the 4,4’-methylenedicyclohexyl

diisocyanate is transported in ISO containers, and to a minor part, in drums.

During 4,4’-methylenedicyclohexyl diisocyanate manufacturing and processing, virtually no

4,4’-methylenedicyclohexyl diisocyanate (< 25 kg/a) is emitted into the atmosphere from the Bayer plants. Waste

from the manufacturing and processing of 4,4’-methylenedicyclohexyl diisocyanate is disposed off in an

incinerator for hazardous wastes. Due to wastewater-free manufacturing and processing, and to rapid hydrolysis,

no emissions into the aquatic environment are expected.

Surveys of the workplaces have been performed also according to German Technical Guidance TRGS 402,

TRGS 430, and TRGS 900 by the producer in Germany. To protect workers from exposure, several

precautionary and protective measures are taken, e.g., sampling takes place in a widely closed system. In

Germany for occupational settings, the maximum permissible concentration for 4,4’-methylenedicyclohexyl

diisocyanate is 0.054 mg/m3. At the producer in Germany, all exposure data were below the maximum

permissible concentration.

No environmental monitoring data have been identified. Traces of 4,4’-methylenedicyclohexyl diisocyanate (up

to 2 μg/m3) were detected as a thermolytic degradation product during joint welding of polyurethane floor

covering in a small room with no ventilation.

The exposure of consumers to 4,4’-methylenedicyclohexyl diisocyanate is unlikely to occur, because no

consumer product is known to contain 4,4’-methylenedicyclohexyl diisocyanate. An exposure via the

environment is also unlikely to occur because there are virtually no emissions of 4,4’-methylenedicyclohexyl

diisocyanate, and 4,4’-methylenedicyclohexyl diisocyanate released to environment would rapidly be degraded

by photooxidants and water.

RECOMMENDATION AND RATIONALE FOR THE RECOMMENDATION AND

NATURE OF FURTHER WORK RECOMMENDED

Human Health: The chemical possesses properties indicating a hazard for human health (severe irritation of skin,

eye and respiratory tract, sensitization of skin and predicted to be a respiratory tract sensitizer because it is a

diisocyanate). Based on data presented by the Sponsor country (relating to production by one producer which

accounts for approximately 5 % to 50 % of global production and relating to the use pattern in several OECD

countries), occupational exposure is anticipated to be low and there are no known consumer uses. Therefore this

chemical is currently of low priority for further work. Countries may desire to investigate any exposure scenarios

that were not presented by the Sponsor country.

Environment: The chemical (including its hydrolysis products) possesses properties indicating a hazard for the

environment. Based on data presented by the Sponsor country (relating to production by one producer which

accounts for approximately 5 % to 50 % of global production and relating to the use pattern in several OECD

countries), exposure to the environment is anticipated to be low, and therefore this chemical is currently of low

priority for further work. Countries may desire to investigate any exposure scenarios that were not presented by the

Sponsor country.

5
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

SIDS Initial Assessment Report

1 IDENTITY

Identification of the Substance

CAS Number: 5124-30-1

Substance name 4,4 ́-methylenedicyclohexyl diisocyanate (EINECS name)

IUPAC Name: 1,1 ́-Methylenebis(4-isocyanatocyclohexane)

Molecular Formula: C15H22N2O2

Structural Formula:

N

C

O

N

C

O

Molecular Weight: 262.35 g/mol

Synonyms: Cyclohexane, 1,1’-methylenebis-(4-isocyanato)- (CAS name)

Desmodur W (Product of Bayer MaterialScience AG)

Hylene W

Hydrogenated MDI

H12MDI

Methylene bis(4-cyclohexylisocyanate)

4,4’-Dicyclohexylmethanediisocyanate

4,4’-Diisocyanatodicyclohexylmethane

4,4’-Methylenebis(cyclohexyl isocyanate)

Bis(4-isocyanatocyclohexyl)methane

Dicyclohexylmethane-4,4'-diisocyanate

Methylenebis(1,4-cyclohexylene) diisocyanate

Methylene bis(4-isocyanatocyclohexane)

Methylenedi-1,4-cyclohexylene isocyanate

Methylenedi-4-cyclohexylene diisocyanate

Purity/Impurities/Additives

A typical composition of 4,4’-methylenedicyclohexyl diisocyanate was specified by Dieterich and

Uhlig (2002) with a purity of 92 % 4,4’-methylenedicyclohexyl diisocyanate and the corresponding

isomeric composition:

• cis,cis-isomer 14 %

• cis,trans-isomer 58 %

• trans,trans-isomer 20 %

• others 8 % (2,4'-methylenedicyclohexyl diisocyanate).

The commercial product of 4,4’-methylenedicyclohexyl diisocyanate also contains

2,4’-methylenedicyclohexyl diisocyanate (Bayer MaterialScience AG, 2004a).

6
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

Physico-Chemical properties

Table 1 Summary of physico-chemical properties of 4,4’-methylenedicyclohexyl

diisocyanate

Property Value Reference IUCLID

Substance type Organic compound Bayer MaterialScience

AG, 2004b

1.1.1

Physical state Slightly yellowish liquid with

slight lachrymatory odour

Bayer MaterialScience

AG, 2004b

1.1.1

Melting point 15 °C** Dieterich and Uhlig, 2002 2.1

Boiling point 167 - 168 °C (at 2 hPa) GIAP, 1969 2.2

Relative density 1.07 at 25 °C NIOSH, 2004 2.3

Vapour pressure 2.13 x 10-5 hPa at 25 °C Bayer AG, 1994a 2.4

Partition coefficient noctanol/water (Kow)Calculation is not suitable due

to hydrolysis*

2.5

Water solubility Hydrolysis* NIOSH, 2004 2.6.1

Flash point 200 °C Bayer AG, 1979 2.7

Ignition point 225 °C Zhuravlev, 1976 2.8

Viscosity ca. 30 mPa x s at 25 °C Bayer MaterialScience

AG, 2004b

2.13

*In water, 4,4’-methylenedicyclohexyl diisocyanate hydrolyses with a half-life of approximately 2 h

(Bayer AG, 1999) **For the mixture reported by Dieterich and Uhlig (2002) in Chapter 1.2. Melting point may

vary according to exact isomeric composition.

2 GENERAL INFORMATION ON EXPOSURE

Production Volumes and Use Pattern

Commercial 4,4’-methylenedicyclohexyl diisocyanate manufacturing starts with hydrogenated

methylenedianiline (4,4’-methylenebis(cyclohexylamine), CAS 1761-71-3) which is generally

known as H12MDA or PACM. PACM is a mixture of three isomers, trans,trans-, cis,trans-, and

cis,cis-PACM which is obtained by catalytic hydrogenation of methylenedianiline (MDA). PACM

is phosgenated (Six and Richter, 2003):

NH2-C6H4-CH2-C6H4-NH2 + 2 COCl2 → OCN-C6H10-CH2-C6H10-NCO + 4 HCl

During phosgenation hydrochloric acid is stripped and recycled to yield chlorine for the phosgene

production. The isocyanate is dried and distilled. The reaction product consists of 92 %

4,4’-methylenedicyclohexyl diisocyanate with 14 % cis,cis-isomer, 58 % cis,trans-isomer, and

20 % trans,trans-isomer (Dieterich and Uhlig, 2002), the 2,4 ́-isomers accounting for the remaining

approx. 8 % (Bayer MaterialScience AG, 2004a). Since the trans,trans-4,4’-methylenedicyclohexyl

diisocyanate is solid in the pure state [melting point 83 °C (Dieterich and Uhlig, 2002)], to obtain a

liquid diisocyanate product in the subsequent phosgenation, the amount of trans,trans4,4’-methylenebis(cyclohexylamine) has to be reduced to less than 20 % (selective hydrogenation

and/or crystallisation) (Six and Richter, 2003).

7
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

The global production capacity of 4,4’-methylenedicyclohexyl diisocyanate is 10,000 - 20,000

tonnes/a, with most of it in the USA (Bayer MaterialScience AG, 2004a). In Germany, Bayer

MaterialScience AG (2004a) is the only producer and has a manufacturing capacity of 1000 - 5000

tonnes/a of 4,4’-methylenedicyclohexyl diisocyanate.

4,4’-Methylenedicyclohexyl diisocyanate is used as an intermediate in several industries, e.g. the

chemical industry and coatings industry. 4,4’-Methylenedicyclohexyl diisocyanate is used as a

monomer and is industrially processed to polymers with e.g. polyols in the coatings industry to

produce e. g. binders, prepolymers, and elastomers. 4,4’-Methylenedicyclohexyl diisocyanate is

supplied to the chemicals industry, mainly coatings industry, but is not distributed to consumers. It

is used for the manufacture of

• Binders or hardeners for coating materials or adhesives (60 %)

• Prepolymers (20 %)

• Others, e.g. for the production of elastomers (20 %) (Bayer MaterialScience AG, 2004a).

4,4’-Methylenedicyclohexyl diisocyanate is not used for “Do it Yourself” applications or in other

consumer products (Bayer MaterialScience AG, 2004a). Consistently, 4,4’-methylenedicyclohexyl

diisocyanate is registered as a component in approximately 50 industrial products in the Danish,

Finnish, and Swedish Product Registers with a consumption of about 30 metric tonnes/a in 2000

and 2001 (last years of record). It is used as an intermediate for the manufacture of rubber and

plastic products, industrial paints, chemical products, construction and transport equipment. There

is no registration for a consumer product. It is confidentially listed in the Norwegian Product

Register. The main use category is “non-dispersive use” (SPIN, 2004).

The Swiss Product Register (2004) lists 34 industrial products (with concentrations of up to 100 %

4,4’-methylenedicyclohexyl diisocyanate), but no consumer product containing 4,4’-methylenedicyclohexyl diisocyanate.

Environmental Exposure and Fate

When 4,4’-methylenedicyclohexyl diisocyanate is released to water, degradation occurs through

hydrolysis (cf. Chapter 2.2.3). A half-life of approximately 2 hours was determined for

4,4’-methylenedicyclohexyl diisocyanate (Bayer AG, 1999). The hydrolysis product

4,4’-methylenebis(cyclohexylamine) was assessed by the EU PBT Working Group (2003). The

hydrolysis product was not classified as a PBT (persistent, bioaccumulative, toxic) substance.

Sources of Environmental Exposure

Environmental information from manufacturing and processing of 4,4’-methylenedicyclohexyl

diisocyanate is available for the Bayer plants in Germany. Both plants are at the same industrial site

(Bayer MaterialScience AG, 2004a).

Since phosgene (precursor) and 4,4’-methylenedicyclohexyl diisocyanate (product) react violently

with traces of water, the synthesis is performed in a closed, water-free system (Bayer

MaterialScience AG, 2004a).

The exhausts from manufacturing and processing are connected to a thermal exhaust purification

plant. Amine and isocyanate tanks are secured with activated carbon filters. The product is

automatically filled into special metal drums or ISO containers (20 feet containers) using suction

devices and widely closed systems (cf. Chapter 2.3.1). Thus, according to the current Official

8
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

Emission Declaration of the year 2000, Bayer emitted virtually no 4,4’-methylenedicyclohexyl

diisocyanate (< 25 kg/a) into the atmosphere during manufacturing and processing (Bayer

MaterialScience AG, 2004a).

Waste from the manufacturing and processing is incinerated in an incinerator for hazardous wastes

(Bayer MaterialScience AG, 2004a).

Due to the water sensitivity of precursors and product, 4,4’-methylenedicyclohexyl diisocyanate is

manufactured in closed system virtually free of water. Water is used only in the case of maintenance (after the system has been eluted with solvent), to flush the system to ensure hydrolysis of

phosgene. Due to this procedure, the wastewater does not contain 4,4’-methylenedicyclohexyl

diisocyanate. However, all wastewater from manufacturing and processing is led into a Bayerowned wastewater treatment plant (hydraulic retention times > 1 d), where 4,4’-methylenedicyclohexyl diisocyanate would be hydrolyzed (cf. Chapter 2.2.3). No additional information is

available from other companies (Bayer MaterialScience AG, 2004a). However, there is no doubt

that rules were abided to and regulations are strictly met in the Sponsor country.

Photodegradation

There are no experimental data on the stability of 4,4’-methylenedicyclohexyl diisocyanate in the

atmosphere. A half-life of about 15 hours is estimated due to reaction with photochemically produced hydroxyl radicals, considering a mean OH concentration of 0.5 x 106 OH radicals/cm3 as a

24 h-average (Bayer Industry Services, 2004a) (cf. Table 2). However, the AOPWIN program used

for this estimate does not take into account that 4,4’-methylenedicyclohexyl diisocyanate is

sensitive to hydrolysis e.g. in aerosols with aquatic phases.

Table 2 Photodegradation of 4,4’-methylenedicyclohexyl diisocyanate (IUCLID 3.1.1)

Parameter Method Result Reference

Indirect

photodegradation

in air

Calculation for 24 h-day,

500,000 OH/cm3,

Rate constant =

25.8 x 10-12 cm3/(molecule x s)

t1/2 = 15 h Bayer Industry Services, 2004a

Stability in Water

4,4’-Methylenedicyclohexyl diisocyanate hydrolyzes rapidly in the presence of water. A half-life

for 4,4’-methylenedicyclohexyl diisocyanate hydrolysis of approximately 2 hours was determined

experimentally (Bayer AG, 1999).

In this study performed in accordance with the GLP-requirements, 1 g/l 4,4’-methylenedicyclohexyl

diisocyanate dissolved in an acetonitrile/water-mixture was investigated at 23 °C. The decrease of

NCO-content was observed in this solution during the study period. For this purpose the

concentration of 4,4’-methylenedicyclohexyl diisocyanate was determined by means of capillary

gas chromatography using flame ionization detection at continuous time intervals (cf. Table 3).

The rapid hydrolysis means that 4,4’-methylenedicyclohexyl diisocyanate discharged into the

environment will be abiotically degraded.

A preliminary test according to the OECD TG 111 was carried out with

4,4’-methylenedicyclohexyl diisocyanate to determine the resulting products from the reaction with

9
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

water. A solution of 2.64 g/l was incubated in demineralized, unbuffered water at 50 °C during

5 days under continuous stirring (Bayer Industry Services, 2004b). 

In the aqueous phase the three isomers of 4,4’-methylenebis(cyclohexylamine) were identified with

GC- and HPLC-MS. Additionally, the HPLC-analysis showed to a minor extent traces of a trimeric

diamine compound; this was bound by urea-groups. Insoluble droplets obtained during hydrolysis

testing adhered to the glass wall. They were analyzed with IR spectroscopy and were found to

contain urea components (polymeric urea) and encapsulated traces of isocyanate-groups (Bayer

Industry Services, 2004b). This hydrolysis product is more or less inert and - because of its

macromolecular size - not bioavailable. In addition, this substance is formed only in the case of high

isocyanate concentration which does not correspond to environmental conditions (EU PBT

Working Group, 2003).

Table 3 Hydrolysis of 4,4’-methylenedicyclohexyl diisocyanate (IUCLID 3.1.2)

Test substance Procedure Result Reference

4,4’-methylenedicyclohexyl

diisocyanate

50 % acetonitrile, 50 % water

Determination of NCO-content

using GC analysis with FID

detection

t1/2 = 1.97 hours at 23 °C;

Rate constant kobs =

9.78 x 10-5 1/s

Bayer AG, 1999

Transport between Environmental Compartments

In the aquatic environment, 4,4’-methylenedicyclohexyl diisocyanate will undergo hydrolysis

(Bayer AG, 1999). Due to the rapid hydrolysis of 4,4’-methylenedicyclohexyl diisocyanate, a

transport of the substance between environmental compartments is unlikely.

A calculation of the Henry Law Constant and also of the distribution between the environmental

compartments according to the Mackay fugacity model level 1 is not suitable due to the hydrolyzing

properties of 4,4’-methylenedicyclohexyl diisocyanate.

For the hydrolysis product, 4,4’-methylenebis(cyclohexylamine), a Henry Law Constant of

0.00046 Pa-m3/mole is obtained by the Bond method and of 0.016 Pa-m3/mole by the vapor

pressure/water solubility equation (US EPA, 2005). The Mackay results are compiled in Table 4.

The predominant environmental compartment of the hydrolysis product is water (98 %) (EU PBT

Working Group, 2003).

10
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

Table 4 Input parameters and results for 4,4’-methylenebis(cyclohexylamine) of the 

Mackay Fugacity Model Level I (IUCLID 3.3.2)

Input Parameters Value

Molar mass 210.36 g/mol

Temperature 20 °C

Vapour pressure 0.033 Pa 

Water solubility 5800 g/m3

log Kow 2.03

Melting point 320 °C

Compartment Calculated distribution

Water 98.256 %

Air 0.041 %

Sediment 0.823 %

Soil 0.880 %

Aquatic Biota 0.001 %

Biodegradation

Based on the available experimental biodegradation test result for 4,4’-methylenedicyclohexyl

diisocyanate, the substance is classified as not readily biodegradable (cf. Table 5). No test on

inherent biogradability is available.

In a GLP-study which was conducted according to Directive 92/69/EEC C.4-D (Manometric

Respirometry Test), the biodegradation of 4,4’-methylenedicyclohexyl diisocyanate was investigated with a test substance concentration of 100 mg/l (no toxicity to bacteria observed). Within the

test period of 28 days, a degradation of 0 % was determined for 4,4’-methylenedicyclohexyl

diisocyanate (Bayer AG, 2000a).

In a GLP-study which was conducted according to OECD TG 301F, the biodegradation of

4,4’-methylenedicyclohexyl diisocyanate was tested at an initial concentration of 12 mg/l because a

preliminary test at 100 mg/l indicated that the substance was toxic to bacteria present in the sewage

sludge. This difference of toxicity between the two tests, both performed with an inoculum from a

domestic sewage sludge, is presumably due to changes in sludge properties. Within the test period

of 28 days, a degradation of 0 % was determined for 4,4’-methylenedicyclohexyl diisocyanate

(Bayer AG, 1992).

Table 5 Biodegradation of 4,4’-methylenedicyclohexyl diisocyanate (IUCLID 3.5)

Inoculum Procedure Result Reference

Aerobic predominantly

domestic sewage

Directive 92/69/EEC,

C.4-D

0 % degradation after 28 days Bayer AG, 2000a

Domestic activated

sludge

OECD TG 301F 0 % degradation after 28 days Bayer AG, 1992

The biodegradability of the hydrolysis product, 4,4’-methylenebis(cyclohexylamine), was

calculated with the EPIWIN BIOWIN (v4.02) Program. Four out of six estimation methods predict

11
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

fast biodegradation, with an ultimate biodegradation timeframe of weeks (US EPA, 2005). The EU

PBT Working Group (2003) assessed biodegradation tests on the hydrolysis product

4,4’-methylenebis(cyclohexylamine). These tests show that 4,4'-methylenebis(cyclohexylamine) is

at least inherently biodegradable.

Bioaccumulation

Measured bioconcentration factors (BCF) for 4,4’-methylenedicyclohexyl diisocyanate are not

available.

4,4’-Methylenedicyclohexyl diisocyanate hydrolyzes rapidly in the presence of water with a half

life of approximately 2 hours. Therefore a risk estimation regarding the bioaccumulation potential

of 4,4’-methylenedicyclohexyl diisocyanate on the basis of a log Kow, determined by QSAR, is

misleading. A calculated theoretical log Kow value reflects the undissociated molecule without

influence of water.

According to the EU Technical Guidance Document a substance is regarded as potentially

bioaccumulative if the log Kow exceeds 3 and the half life time in water exceeds 12 hours. This is

not the case for 4,4’-methylenedicyclohexyl diisocyanate. The substance is not persistent in water

due to the rapid hydrolysis. Therefore it is not bio-available. Possible hydrolyzation products are

less lipophilous. On the basis of these information it can not be expected that bioaccumulation of

4,4’-methylenedicyclohexyl diisocyanate occurs (Bayer Industry Services, 2003).

The hydrolysis product, 4,4’-methylenebis(cyclohexylamine) is also not bioaccumulative (EU PBT

Working Group, 2003). With a measured log Kow (OECD 107) of 2.03, and calculated log Kow

values of 2.55 (CLOGP3 program) (EU PBT Working Group, 2003) and 3.26 (EPIWIN BCF

Program (v2.15)) (US EPA, 2005), log BCF values of 0.863 (BCF = 7), 1.264 (BCF = 18), and

1.814 (BCF = 65) were calculated, respectively.

Geoaccumulation

There are no experimental data on the geoaccumulation potential of 4,4’-methylenedicyclohexyl

diisocyanate, because the substance hydrolyzes rapidly in aqueous environment.

The distribution of 4,4’-methylenedicyclohexyl diisocyanate between the organic phase of soil or

sediments and the porewater was calculated using QSAR. With the PCKOC program (v 1.66), a

Koc-value of 3.8 x 105 was calculated for 4,4’-methylenedicyclohexyl diisocyanate (Bayer Industry

Services, 2004a). For the hydrolysis product, 4,4’-methylenebis(cyclohexylamine), a Koc of 672 is

obtained (US EPA, 2005) (cf. Table 6).

Table 6 Geoaccumulation properties of 4,4’-methylenedicyclohexyl diisocyanate and

its hydrolysis product (IUCLID 3.3.1)

Compound Method Result Reference

4,4’-methylenedicyclo

hexyl diisocyanate

Soil organic carbon-water

distribution coefficient calculated

with PCKOCWIN, v.1.66

Koc = 3.762 x 105,

log Koc = 5.575

Bayer Industry Services,

2004a

4,4’-methylenebis

(cyclohexylamine)

Soil organic carbon-water

distribution coefficient calculated

with PCKOCWIN, v.1.66

Koc = 672 US EPA, 2005

12
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

According to Litz (1990) 4,4’-methylenedicyclohexyl diisocyanate should be regarded as a

substance with very high geoaccumulation properties. However, geoaccumulation in soil will be

affected by humidity due to its rapid hydrolysis.

It is therefore concluded that geoaccumulation of 4,4’-methylenedicyclohexyl diisocyanate is

unlikely to occur. The hydrolysis product has only a small to medium tendency for

geoaccumulation.

Environmental Monitoring

No data have been identified.

Human Exposure

Occupational Exposure

Occupational exposure to 4,4’-methylenedicyclohexyl diisocyanate is most likely to occur through

inhalation and dermal routes.

Workplaces

At the Bayer manufacturing site, some 4,4’-methylenedicyclohexyl diisocyanate is also used in the

production of powder coatings. During this processing 4,4’-methylenedicyclohexyl diisocyanate is

converted into a polymeric resin (Bayer MaterialScience AG, 2004a). Workplaces where

4,4’-methylenedicyclohexyl diisocyanate is manufactured and processed include (cf. Chapter 2.1)

• the synthesis of phosgene from carbon monoxide and chlorine supplied via pipelines from other

manufacturers in the Bayer integrated industrial site and

• the synthesis of 4,4’-methylenedicyclohexyl diisocyanate from phosgene and PACM, and

finally

• the isolation and filling of 4,4’-methylenedicyclohexyl diisocyanate , and

• the processing of 4,4’-methylenedicyclohexyl diisocyanate.

4,4’-Methylenedicyclohexyl diisocyanate is manufactured in closed systems (cf. Chapters 2.1 and

2.2.1).

To the customers most of the 4,4’-methylenedicyclohexyl diisocyanate is transported in ISO

containers, and (a minor part) in drums (Bayer MaterialScience AG, 2004a).

Precautionary measures at the workplace

In accordance with the principles of Responsible Care and Sustainable Development, at Bayer the

exposure of workers is reduced to the lowest technically practicable level (Bayer MaterialScience

AG, 2004a).

Surveys of the Bayer workplaces are performed according to German Technical Guidances

TRGS 402 (1997), TRGS 430 (2004), and TRGS 900 (2004). This includes regular surveys in the

production plant for any possible exposure to phosgene, an organic solvent, and

4,4’-methylenedicyclohexyl diisocyanate under all relevant work situations, and application of

13
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

appropriate control measures. In the processing plant, 4,4’-methylenedicyclohexyl diisocyanate is

monitored (Bayer MaterialScience AG, 2004a).

To protect workers from exposure, several precautionary and protective measures are taken. E.g.,

sampling takes place in a widely closed system. For filling in ISO containers the workers have to

wear full protective clothing and gas filter masks. Repair and maintenance work is only carried out

on parts of the manufacturing system, which have been emptied. Prior to repair and maintenance the

relevant components are flushed with solvent and water to remove residual substances. Special

written permits are required which include a detailed description of the protective measures

depending on the work to be done (e.g., full protective clothing and gas filter masks (classification

ABEK)) (Bayer MaterialScience AG, 2004a).

Down stream users of 4,4’-methylenedicyclohexyl diisocyanate are informed by way of a material

safety data sheet on the recommended safety measures (see above) (Bayer MaterialScience

AG, 2004a).

Potential exposure at the workplace

In Germany for occupational settings, the maximum permissible concentration for 4,4’-methylenedicyclohexyl diisocyanate is 0.054 mg/m3 according to TRGS 900.

The main process to manufacture 4,4’-methylenedicyclohexyl diisocyanate is by a phosgenation

process. Thus special safety measures are taken to prevent any risk of exposure. These measures

include a continuous phosgene monitoring coupled with an automatic water/ammonia spray system

for abatement. Since 4,4’-methylenedicyclohexyl diisocyanate is closely associated with phosgene

during manufacturing, these measures are also suited to ensure that neither the environment nor the

workers are exposed to 4,4’-methylenedicyclohexyl diisocyanate. In the processing area, where

4,4’-methylenedicyclohexyl diisocyanate is used to manufacture powder coatings, 17

4,4’-methylenedicyclohexyl diisocyanate measurements (8 total shift and 9 short term measurements) were made between 1994 and 2001. All results were below the maximum permissible

concentration (Bayer MaterialScience AG, 2004a).

Thermal degradation products formed during grinding and welding of certain polyurethanes were

reported to include 4,4’-methylenedicyclohexyl diisocyanate. Traces of 4,4’-methylenedicyclohexyl

diisocyanate (up to 2 μg/m3) were detected as a thermolytic degradation product during joint

welding of polyurethane floor covering in a small room with no ventilation in a car repair shop

(Henriks-Eckerman et al., 2002).

4,4’-Methylenedicyclohexyl diisocyanate (which was used for the manufacturing of water pipes

equipped with water flow measuring devices), was not detectable with a limit of detection of

< 0.0006 mg/sample (< 0.0022 μg/l) in workplace air of an US plant (Lewis, 1980).

Consumer Exposure

4,4’-Methylenedicyclohexyl diisocyanate is exclusively used as an intermediate in chemical

processes. A direct use of this substance is not known (Bayer MaterialScience AG, 2004a).

Consistently, there is no registration of a consumer product containing 4,4’-methylenedicyclohexyl

diisocyanate in the Danish, Finnish, Swedish (SPIN, 2004), and Swiss Product Register (2004).

4,4’-Methylenedicyclohexyl diisocyanate is confidentially listed in the Norwegian Product Register

(SPIN, 2004), but since the main use category is “non-dispersive use”, it is assumed that the

confidential registration is also for industrial use only.

14
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

The exposure of consumers to 4,4’-methylenedicyclohexyl diisocyanate is unlikely to occur via

consumer products, because no consumer product is known to contain 4,4’-methylenedicyclohexyl

diisocyanate (Bayer MaterialScience AG, 2004a). An exposure of consumers to 4,4’-methylenedicyclohexyl diisocyanate via the environment is also unlikely to occur because there are virtually

no emissions of 4,4’-methylenedicyclohexyl diisocyanate, and 4,4’-methylenedicyclohexyl

diisocyanate released to environment would rapidly be degraded by photooxidants (cf. Chapter

2.2.2) and water (cf. Chapter 2.2.3).

3 HUMAN HEALTH HAZARDS

Effects on Human Health

Toxicokinetics, Metabolism and Distribution

There are no data available (With regard to information on the fate of 4,4 ́-methylenedicyclohexyl

diisocyanate in aqueous systems see chapter 2.2.3).

Acute Toxicity

Studies in Animals

Inhalation

The acute inhalation toxicity of 4,4 ́-methylenedicyclohexyl diisocyanate (purity > 99.2 %) was

studied by Bayer AG (1995a) by exposing Wistar rats in seven groups, each containing 5 males and

5 females. The method used was essentially that of OECD TG 403. Each group was nose only

exposed to concentrations of the aerosol of the test substance. After exposure (4 hours) the animals

were observed for two weeks. The actual mean concentrations of 4,4 ́-methylenedicyclohexyl

diisocyanate were 151, 388, 418, 552, 730, 865 and 1352 mg/m3. The test substance aerosol

exhibited a particle-size indicating that this aerosol was of adequate respirability (90 % of the

particle mass was ≤ 3 μm; mass median aerodynamic diameter (MMAD) ≈ 1.4 μm; geometric

standard deviation (GSD) ≈ 1.8 μm). Rats exposed to ≥ 151 mg/m3experienced signs of respiratory

tract distress (i.e. salivation, bradypnea, stridor). Exposure to concentrations of ≥ 388 mg/m3caused

mortality, which occurred on the exposure day through post exposure day 4. Gross necropsy

findings (less collapsed lungs including a hemorrhagic lung edema, red secretions in the nose, pale

liver with lobular pattern, pale spleen and kidneys) were observed only in the rats which died during

the observation period The LC50 (4 h) stated in this study (Bayer AG, 1995a) is 434 mg/m3 with

confidence limits (95 %) of 355 - 533 mg/m3 both sexes combined.

Another study report (Mobay Chemical Corp., 1985) documented that the four-hour LC50 of 4,4

 ́-methylenedicyclohexyl diisocyanate (purity technical grade, no further data) to male rats was

295 mg/m3 with 95 % confidence interval of 221 to 380 mg/m3, and to female rats it was 307 mg/m3

with 95 % confidence interval of 268 to 327 mg/m3. The no-observed-effect level was less than

113 mg/m3. The animals were exposed, by heads only, to 4,4 ́-methylenedicyclohexyl diisocyanate

aerosol and observed for two weeks after the exposure. The data on particle size distribution

showed that the mass median aerodynamic diameter (MMAD) of all concentration groups were

≤ 2 μm but the geometric standard deviation (GSD) was in the range of 2.4 to 5.5. Differences in

the analytical method for the determination of the chamber concentration between this study and the

15
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

study conducted by Bayer ten years after (Bayer AG, 1995a) may account for marginal discrepancy

of the LC50-values. Due to the analytical method the airborne concentration measured were

probably lesser than the actual one because the test substance partly would have been captured by

reaction with filter material and/or humidity. Nevertheless the qualitative data of both studies are in

agreement. All compound-exposed animals exhibited nasal and ocular irritation during exposure

and post-exposure and the gross lesions observed were mainly in the nose and lung.

Dermal

In an early acute dermal toxicity study done by Monsanto Co. (1966) 1 rabbit/dose was used in 6

dose groups with alternating sex. 4,4 ́-Methylenedicyclohexyl diisocyanate (purity not specified)

was applied as 50 % solution in corn oil or undiluted at the dose levels of 1000, 1580, 2510 and

3980 mg/kg bw or 6,310 and 10,000 mg/kg bw throughout a 24-hour exposure period. The test site

was covered. There were no deaths. Transient reduction of activity and appetite was observed in

animals at the two high dosage levels. No LD50 could be obtained from this study, and it was

therefore > 10 g/kg bw.

Oral

An early acute oral toxicity study was conducted on rats with 4,4 ́-methylenedicyclohexyl

diisocyanate (purity not specified) in doses up to 12,600 mg/kg bw (administered as 50 % solution

in corn oil). Mortality occurred at ≥ 7940 mg/kg bw and the LD50 was determined to be

9900 mg/kg bw. Toxic symptoms included severe diarrhea, loss of appetite and increasing

weakness. At autopsy liver discoloration and renal hyperemia were recorded (Monsanto Co., 1966).

Conclusion

4,4 ́-Methylenedicyclohexyl diisocyanate is of low oral and dermal acute toxicity with an oral LD50

(rat) of 9900 mg/kg bw and a dermal LD50 (rabbit) > 10,000 mg/kg. Toxic symptoms after oral

administration included severe diarrhea, loss of appetite and increasing weakness. Assessment of

the acute inhalation toxicity data indicates that exposure to respirable aerosols of 4,4 ́-methylenedicyclohexyl diisocyanate confined predominantly to the respiratory tract. Clinical signs (salivation,

bradypnea, stridor) indicated respiratory distress. A hemorrhagic lung edema was considered to be

causative for mortality. An animal study according to OECD TG 403 gives a LC50 (4 h, rat) of

434 mg/m3.

Irritation

Skin Irritation

Studies in Animals

In two well-conducted (but non-GLP) studies according to OECD TG 404 4,4 ́-methylenedicyclohexyl diisocyanate (liquid and solid test sample, no data on purity) was applied under

occlusive dressings for 4 hours to the intact but shaved skin of a group of 6 male albino New

Zealand rabbits (Bayer AG, 1981 a, b)). Skin irritation was assessed after 4, 24, 48, 72 hours and 8

days using the Draize scale. The calculation of the primary irritation index was based on the scores

of the 24 and 72 hours reading times for erythema and edema formation. In these studies 4,4

 ́-methylenedicyclohexyl diisocyanate was considered as moderately irritating to the skin with an

irritation index of 4.2 (liquid sample) and 3.6 (solid sample) of max 8.0 (3.1 - 5.0 = moderately

irritating). At the end of the post observation period (8 days) surface skin scaling was observed.

In a study performed according to OECD TG 404 4,4 ́-methylenedicyclohexyl diisocyanate was

considered as severely irritating to the skin after 4 hours semi-occlusive exposure (Bayer

16
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

AG, 1994b). According to the guideline for reasons of animal welfare, due to the expected irritant

potency of the test substance in the test only one animal was used. The scores according to the

Draize scale of the 24, 48 and 72 hours reading times were used in calculating respective mean

value. The mean value for erythema/eschar formation was 2.7 of max. 4 and the mean value for

edema formation was 1.3 of max. 4. After 14 days the epidermis of the exposed skin area had

become partially detached.

In 1996 the primary dermal irritation/corrosion potential of 4,4 ́-methylenedicyclohexyl diisocyanate was evaluated when applied to the skin of 3 rabbits under semi-occlusive conditions for

exposure periods of 3-minutes, 1-hour, and 4-hours (Bayer Corporation, 1996). For this purpose the

undiluted test material was applied to three separate areas on the intact skin on each animal ́s back.

In this well conducted GLP-study no evidence of corrosion was observed at any of the test sites for

any of the exposure periods. Based on these results, the test material was not considered to be a

corrosive material. Dermal irritation was evident at all exposure sites and was characterized by very

slight to well-defined erythema (scores of 1 to 2 according to the Draize scale of max. 4) and very

slight to slight edema (scores of 1 to 2 according to the Draize scale of max. 4). By day 21 all signs

of edema had subsided and only one animal was noted with very slight erythema at all exposure

sites. However, on day 21, areas of thickened skin were observed at some or all of the exposure

sites for two animals. There were no remarkable signs of clinical toxicity and/or ill health noted

during the course of this study.

Eye Irritation

Studies in Animals

In two studies according to OECD TG 405 4,4 ́-methylenedicyclohexyl diisocyanate (liquid and

solid test sample) was instilled into the conjunctival sac of each eye of 6 male albino New Zealand

rabbits (Bayer AG, 1981 c, d). The right eye was rinsed with saline 30 seconds after instillation and

the left eye remained unrinsed. Eye irritation was assessed using the Draize scale. In these studies

4,4 ́-methylenedicyclohexyl diisocyanate was considered to be not irritating to the eye with an

irritation index (24 - 72 hour) of 3.0 (liquid sample, with/without rinsing) and 0.4 (solid sample,

with rinsing) and 6.3 respectively (solid sample, without rinsing) (0-10 = not irritating). However,

the individual findings at the various observation times (24, 48, 72 hours) showed that irritation of

the conjunctivae was evident for both test samples and both test procedures (with/without rinsing).

Signs of irritation were characterized by redness and chemosis scored 1 to 2. By day 8 all signs of

irritation had subsided for the animals, which have been treated with the solid sample. Slight effects

on the conjunctivae (score 1-2) at the end of the observation period were still observed in 3/6

rabbits treated with the liquid test material. Corneal opacity was restricted to 3/6 (solid/liquid, with

rinsing) and 2/6 (solid, without rinsing) animals and was reversible within 72 hours at the latest.

Respiratory Tract Irritation

Studies in Animals

Based on ‘regulatory’ acute toxicity studies (cf. Chapter 3.1.2) no conclusions can be drawn

regarding the respiratory irritating properties of 4,4 ́-methylenedicyclohexyl diisocyanate. The same

applies for the studies that determined the 4,4 ́-methylenedicyclohexyl diisocyanate concentration

causing a 50 % decrease in respiratory rate (RD50) for mice (Mobay Chemical Corp., 1984; Weyel

and Schaffer, 1985). This test system is restricted to vapors (= upper tract irritant). It is irrelevant

for aerosols for which the deposit pattern strongly depends on the generation of the test atmosphere.

For aerosols irritation of the respiratory tract is apparently more dependent on the specific site

receiving the highest fraction of the dose rather than the total airborne concentration. However, the

repeated dose studies (see 3.1.5 and 3.1.8) do indicate that 4,4 ́-methylenedicyclohexyl diisocyanate

causes irritation of the respiratory tract.

17
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

Conclusion

4,4 ́-methylenedicyclohexyl diisocyanate is moderately to severe irritant to the skin of rabbits

(OECD TG 404). Irritant effects were observed after instillation of 4,4 ́-methylenedicyclohexyl

diisocyanate into the eyes of rabbits (OECD TG 405). The repeated dose studies indicate that 4,4

 ́-methylenedicyclohexyl diisocyanate causes irritation of the respiratory tract.

Sensitisation

Studies in Animals

Skin

4,4 ́-Methylenedicyclohexyl diisocyanate, was assessed for sensitizing properties using a modified

Guinea pig maximization test of Magnusson and Kligman by Bayer AG (1984). 4,4

 ́-Methylenedicyclohexyl diisocyanate, 10 % in paraffin oil and Freund’s Complete Adjuvant were

injected intracutaneously on days 0 and 7 in 20 Guinea pigs. Dermal provocation applications of

0.03 and 0.1 % 4,4 ́-methylenedicyclohexyl diisocyanate in paraffin oil were made on day 21 (6

hours) and on day 35 (6 hours). Two negative control groups (one control group for each challenge)

of 10 animals were treated with Freund’s Complete Adjuvant and paraffin oil. 4,4 ́-Methylenedicyclohexyl diisocyanate was not considered to be a skin sensitizer in this test.

This negative test result was confirmed by the findings of the same laboratory using the Guinea pig

maximization test of Magnusson and Kligman, which comply mostly with OECD TG 406 (Bayer

AG, 1985). 4,4 ́-Methylenedicyclohexyl diisocyanate, 1 % in paraffin oil and Freund’s Complete

Adjuvant were injected intracutaneously on day 0 in 20 Guinea pigs. The topical induction was

done on day 7 with 10 % 4,4 ́-methylenedicyclohexyl diisocyanate for 48 hours. Dermal provocation applications of 0.001 and 0.01 % 4,4 ́-methylenedicyclohexyl diisocyanate in paraffin oil

were made on day 21 (24 hours, occlusive). A negative control group of 10 animals was treated

with Freund’s Complete Adjuvant and paraffin oil.

The fact that slightly irritating test concentrations were applied for the challenge in both studies

does not invalidate the findings that 4,4 ́-methylenedicyclohexyl diisocyanate is not a skin sensitizer

in the Guinea pig maximization test.

Positive results were reported for 4,4 ́-methylenedicyclohexyl diisocyanate in the Buehler Assay

(American Cyanamid Company 1984; Zissu, Binet and Limasset, 1998), mouse ear swelling test

(Stadler and Karol, 1985; Thorne et al., 1987), the local lymph node assay (Dearman, Basketter and

Kimber, 1992; Dearman, Spence and Kimber, 1992).

Stadler and Karol (1984) dealt with the relationship between inhalation of 4,4 ́-methylenedicyclohexyl diisocyanate and the development of dermal sensitivity. For this purpose mice and

guinea pigs were exposed to an aerosol (4,4 ́-methylenedicyclohexyl diisocyanate in acetone) for 2

hours/day on 3 consecutive days. Both species exhibited contact sensitivity upon subsequent dermal

challenge whereas caution must be exercised because nose-only exposure system has an

unavoidable contribution of dermal involvement.

Respiratory Tract

In an unpublished report of Bayer AG (1995b), sensitization of 8 guinea pigs with a single

intradermal injection of 4,4 ́-methylenedicyclohexyl diisocyanate (100 μl, 0.13% solution in olive

oil) followed after four weeks by inhalation challenge with the 4,4 ́-methylenedicyclohexyl

diisocyanate hapten (30 min, 68 ± 3.6 mg/m3) was examined. No immediate-onset responses were

observed. Gross pathological examinations showed roughly the same incidence of lung changes in

18
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

all Guinea pigs of this study. The histopathological assessment of the degree of eosinophilia revealed an increased influx of eosinophilic granulocytes in animals sensitized with 4,4 ́-methylenedicyclohexyl diisocyanate. Because eosinophils are known to play a critical role in pathogenesis of

asthma and of other hyperresponsive airway diseases the study provided evidence that 4,4

 ́-methylenedicyclohexyl diisocyanate is a weak respiratory sensitizer in guinea pigs.

In another set of studies, the Murine Local Lymph Node Assay (LLNA) and Mouse IgE Test were

used for the identification of respiratory allergens, frequently associated with specific IgE antibody

(Dearman, Basketter and Kimber, 1992; Dearman, Spence and Kimber, 1992). These data suggest

that 4,4 ́-methylenedicyclohexyl diisocyanate appears not to induce respiratory sensitization. In

another study no pulmonary sensitivity was detected in any of 12 guinea pigs sensitized by topical

exposure to 4,4 ́-methylenedicyclohexyl diisocyanate (Karol and Magreni, 1982).

Although some animal studies have been published for this endpoint, none are considered as

validated assays to assess the potential for respiratory sensitization or asthma in humans.

Studies in Humans

Skin

In humans, case reports have demonstrated skin effects usually attributable to occupational

exposure to 4,4 ́-methylenedicyclohexyl diisocyanate (Emmett, 1976; Malten, 1977; King, 1980;

Israeli, Smirnov and Sculsky, 1981; Hoffman 1982; White, 1982; White, Stewart and

Rycroft, 1983; Thompson and Belisito, 1997; Frick et al., 2003). Some of these cases were

subsequently determined to be cases of dermal sensitization as confirmed by patch testing.

Respiratory Tract

There are no data available.

Conclusion

Animal data are not uniform however they frequently provide evidence of a skin sensitizing

potential of 4,4 ́-methylenedicyclohexyl diisocyanate. Human case reports describe allergic contact

dermatitis due to 4,4 ́-methylenedicyclohexyl diisocyanate exposure. Although no validated animal

model is available to assess the potential for respiratory sensitization or asthma in humans, animal

data support to some extent the hypothesis that respiratory hypersensitivity may be induced by 4,4

 ́-methylenedicyclohexyl diisocyanate.

Repeated Dose Toxicity

Studies in Animals

No repeated-dose toxicity studies are available for the oral and dermal route of exposure.

Inhalation

A subacute 4-week inhalation study with 4,4 ́-methylenedicyclohexyl diisocyanate according to the

OECD TG 412 was performed with male and female Wistar rats (Bayer MaterialScience

AG, 2004d). The rats were exposed under dynamic directed-flow nose-only exposure conditions for

6 hours/day on 5 days a week to 0, 1, 6 and 36 mg/m3(= target concentration). The mean actual

exposure concentrations (= analytical concentration) were 1.057, 6.022 and 33.83 mg/m3).

Throughout the groups the mass median aerodynamic diameter (MMAD) was in the range of 1.0-

1.2 μm (the geometric Standard deviation ≈2) and therefore was highly respirable to rats. Mortality

did not occur up to the highest concentration tested. No clinical effects were recorded for the rats

19
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

exposed to 1 mg/.m3 At 6 mg/m3in most rats (7/10 males and 7/10 females) a borderline response,

such as nasal discharge (wet nose), was observed whilst at 36 mg/m3in all rats respiratory tract

irritation occurred (bradypnea, labored breathing patterns, irregular breathing patterns, tachypnea,

nasal discharge, stridor, nostrils: red encrustations). The rats of this group experienced a mild

hypothermia. No dose dependent effect on body weights was observed. There was no evidence of

adverse hematological effects. Clinical-chemistry and urinalysis were without pathological findings.

There were relative to body weight significantly elevated lung weights (app. 12 %) in rats of the

high-level exposure group. No statistically significant or conclusive changes of the other absolute or

relative organ weights were observed. Histopathological changes were restricted to the nasal

cavities, pharynx, larynx, bronchi and lungs, which became unequivocal evident at 36 mg/m3and

which occurred at 6 mg/m3in borderline intensity. All findings are suggestive of a direct local

irritant mechanism at the location of initial deposition of aerosol. The laryngeal squamous epithelial

metaplasia, which was observed at all exposure concentrations is considered to be a rather ratspecific response and causally related to adaptive rather than adverse effects. Therefore 1 mg/m3

constitutes a no-observed-adverse-effect-level (NOAEL) for effects governed by respiratory tract

irritation (histopathological changes in nasal passages, pharynx, bronchi and lung).

4,4 ́-Methylenedicyclohexyl diisocyanate has been examined in Wistar rats in a reproduction /

developmental Toxicity Screening Test according to OECD TG 421 (for details and exposure

period see Chapter 3.1.8; Bayer MaterialScience AG, 2004e). The rats were exposed nose-only

daily for 6 hours/day to nebulized 4,4 ́-methylenedicyclohexyl diisocyanate in concentrations of 0,

1, 6 and 36 mg/m3(= target concentrations). In all exposure groups, the aerosol was highly

respirable to rats, i.e., the average mass median aerodynamic diameter (MMAD) was ≈ 1 μm, the

geometric standard deviation (GSD) was ≈ 2. No test substance-related effects on the appearance,

health or behavior were observed in the F0 parental animals up to 36 mg/m3except for clear signs of

respiratory tract irritation (changes in breathing behavior) at 36 mg/m3. At 6 mg/m3only serous

nasal discharge and red encrusted nostrils were noted in F0 rats. One male of the high dose group

was found dead during the premating period and one female of the high dose group has to be killed

in moribund condition. Body weight gain was reduced in both sexes at 36 mg/m3at some time

points. Transient reduced food consumption was restricted to the males of the high dose group. The

absolute and relative lung weights were significantly elevated (14 and 18 %, respectively) at

36 mg/m3in male rats. Thus the NOAEL of the subacute study (= 1 mg/m3) corresponds to these

findings.

Conclusion

No results from repeated-dose toxicity tests are available for the oral and dermal route of exposure.

A subacute inhalation study (1, 6 and 36 mg/m3; 6 hours/day on five days/week for 4 weeks) with

rats according to the OECD TG 412 indicates the respiratory tract to be the target organ of

respirable 4,4 ́-methylenedicyclohexyl diisocyanate aerosol. The reported NOAEL for effects

governed by respiratory tract irritation is 1 mg/m3; the LOAEL is 6 mg/m3(i.e. histopathological

changes in nasal passages, larynx and bronchi). The results of the reproduction/developmental

toxicity screening test (OECD TG 421) corresponds to the results of the subacute study.

Mutagenicity

In vitro Studies

4,4 ́-Methylenedicyclohexyl diisocyanate did not induce gene mutations in Salmonella typhimurium

strains TA 1535, TA 1537, TA 98, TA 100 and TA 102 in an Ames test under GLP, and according

to OECD TG 471 (Bayer MaterialScience AG, 2005). Concentrations of up to 50 μg/plate (with S9-

mix) and 16 μg/plate (without S9-mix) were used. 4,4 ́-Methylenedicyclohexyl diisocyanate

20
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

showed a strain-specific cytotoxicity, starting at 1.6 μg/plate. Appropriate reference mutagens were

used as positive controls and showed the expected results throughout all tested strains.

A previous Ames test (DuPont De Nemours, 1977) which does not comply with the current

guideline also gave no evidence for a genotoxic potential of 4,4 ́-Methylenedicyclohexyl diisocyanate in bacteria. Deficiencies of this Ames test from 1977 compared to today ́s guideline are the

number and kind of tester strains, the missing independent repeat experiment and the limited

documentation.

4,4 ́-Methylenedicyclohexyl diisocyanate was tested in the chromosome aberration assay with

Chinese hamster V79 cells in vitro according to OECD TG 473 (Bayer MaterialScience

AG, 2004f). None of the cultures treated with 4,4 ́-methylenedicyclohexyl diisocyanate in the

absence and in the presence of S9 mix up to cytotoxic concentrations (4.5 μg/ml without S9 mix

and 12 mg/ml with S9 mix) showed biologically relevant or statistically significant increased

numbers of aberrant metaphases. The positive controls induced clastogenic effects.

In vivo Studies

There are no data available.

Conclusion

4,4 ́-Methylenedicyclohexyl diisocyanate did not induce gene mutations in bacteria

(OECD TG 471) and demonstrated no potential to induce chromosome aberrations in Chinese

hamster V79 cells mammalian cells in vitro (OECD TG 473) either with or without metabolic

activation

Carcinogenicity

There are no data available.

Toxicity for Reproduction

Studies in Animals

Effects on Fertility

In a reproduction/developmental toxicity screening test according to OECD TG 421 (Bayer

MaterialScience AG, 2004e) Wistar rats (12 animals/sex/dose) were exposed to 4,4 ́-methylenedicyclohexyl diisocyanate aerosol. The rats were exposed nose-only daily for 6 hours/day to

concentrations of 0, 1, 6 and 36 mg/m3(= target concentrations). F0 male and female rats were

exposed for 2 weeks (premating exposure period), which was continued during the approximately 2

week mating period. Males were exposed for at least 28 days (prior to necropsy) whereas the

exposure of the F0 females continued during the pregnancy up to day 19 post coitum (p.c.).

Exposure of the F0 females was suspended up to the day of necropsy on day 4 - 6 p.p. (post partum),

i.e., the time points at which F1 pups were sacrificed. In all exposure groups, the aerosol was highly

respirable to rats, i.e., the average mass median aerodynamic diameter (MMAD) was ≈ 1 μm, the

geometric standard deviation (GSD) was ≈ 2. Clinical signs as changes in breathing behavior and/or

serous nasal discharge were documented for F0 animals of the 6 and 36 mg/m3groups. One male of

the high dose group was found dead during the premating period and one female of the high dose

group had to be killed in moribund condition. No effect on body weights gain, food consumption

and necropsy findings, were observed at ≤ 6 mg/m3. Significant increases of absolute and relative

21
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

weights of the lungs were detected at 36 mg/m3in male rats. No effects of 4,4 ́-methylenedicyclohexyl diisocyanate on reproductive parameters such as insemination index, gestation index

and length and the number of implantation sites were described. At 36 mg/m3a slightly reduced

fertility index was noted (0, 1, 6, 36 mg/m3: fertility index: 91.7, 81.8, 83.8, 66.7* % (*= p > 0.05)).

No remarkable clinical signs were seen in any F1 pubs during the 4 day lactation period and body

weight gain was comparable to the control animals. In the testes of both groups evaluated (control

and high concentration F0 animals) tubular degeneration (mainly multi/focal) was seen in the

majority of animals. In the epididymides, spermatic debris and oligospermia occurred in almost all

rats. These histopathological findings are concordant with the results of the spermatological

evaluation of all animals (no or very low sperm motility and high percentage of abnormal sperms in

control rats and in all concentration groups). Nevertheless the findings seen in the testes are not

substance-related because they were found also in the control animals and they are dose independent. Mechanical stress on the epididymides and testes caused by the narrowness of exposure

restrainers seems to be responsible for the effects seen in all 4,4 ́-methylenedicyclohexyl diisocyanate and air exposed animals.

Based on these findings, the NOAELs were considered to be 1 mg/m3in males and females for

general toxicity. Due to a slightly reduced fertility index at 36 mg/m3, 6 mg/m3is the NOAEL for

reproductive toxicity in rats.

Developmental Toxicity

No effects of 4,4 ́-methylenedicyclohexyl diisocyanate on developmental parameters such as live

birth index and viability index and no apparent malformation were found in pups of a

reproduction/developmental toxicity screening test according to OECD TG 421 in which Wistar

rats (12 animals/sex/dose) have been exposed daily for 6 hours/day during two weeks before mating

until day 19 of gestation to nebulized 4,4 ́-methylenedicyclohexyl diisocyanate in concentrations of

0, 1, 6 and 36 mg/m3 (= target concentrations; Bayer MaterialScience AG, 2004e).

The prenatal toxicity of 4,4 ́-methylenedicyclohexyl diisocyanate in pregnant Wistar rats was

additionally investigated by aerosol inhalation according to OECD TG 414 (Bayer MaterialScience

AG, 2004g). Mated female rats (at least 27/dose) were exposed nose-only to target concentrations

of 0, 1, 6 and 36 mg/m3for 6 h/day from day 6 to day 19 p.c.. Particle size determination of the

aerosol yielded MMADs within the respirable range (≈ 1 μm, the geometric standard deviation

(GSD) ≈ 2). Exposure to 4,4 ́-methylenedicyclohexyl diisocyanate aerosols caused no premature

death. Clinical signs of respiratory tract irritation (i.e. decreased respiratory rates, labored breathing,

irregular respiration and sounds consistent with rhinitis) became apparent at 36 mg/m3.

Furthermore, rough fur, serous nasal discharge, reddish encrusted nostrils, occurred in the 36 mg/m3

group. From a pilot inhalation study (Bayer MaterialScience AG, 2004c) it is known that at this

exposure concentration also the lung weights were significantly increased. At 6 mg/m3only single

females evidenced clinical signs of beginning respiratory irritation. Reduction in food consumption

occurred at 36 mg/m3, which was accompanied by a delay of body weight development during the

treatment period (approximately 24 % below controls) and during gestation (approximately 15 %

below controls). Gross-pathologically no treatment-related findings in the dams occurred at any

concentration. The gestation rate, appearance of placentas, placental weights, postimplantation loss,

number of live fetuses, fetal sex distribution, and fetal weights were unaffected by treatment up to

and including the concentration of 36 mg/m3. With regard to the results on malformation a

marginally increased incidence of ventricular septal defects of the heart (three fetuses out of three

litters, 1.2 % of total fetuses) occurred at the 36 mg/m3level, which lay only marginally above the

upper normal range (0.9 % affected fetuses) of scattering of the rat strain used.

The incidence and type of external or visceral deviations were unaffected by treatment at levels up

to and including 6 mg/m3. A statistically significantly increased incidence of slight dilation of

22
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

lateral brain ventricles occurred at 36 mg/m3. A treatment related effect for this anomaly is unlikely,

as the incidence is normally broadly scattering between unaffected study groups, and because the

value (11.3 % affected fetuses, 56.5 % affected litters) lay within the range of historical control data

and data of different unaffected study groups of the rat strain used (up to 12.7 % affected fetuses, up

to 65.0 % affected litters).

Nevertheless, a NOAEL of 6 mg/m3 was determined in this study with regard to developmental

toxicity.

Conclusion

Data from an inhalative reproduction/developmental toxicity screening test according to

OECD TG 421 with rats (1, 6 and 36 mg/m3) did not reveal substance related impairment of

reproduction up to a 4,4 ́-methylenedicyclohexyl diisocyanate concentration of 6 mg/m3. A slightly

reduced fertility index was observed at an exposure level (36 mg/m3) that was associated with

parental toxicity. NOAELs were considered to be 1 mg/m3in males and females for general

toxicity. NOAEL for reproductive toxicity is 6 mg/m3.

Pre-natal inhalation toxicity testing in rats (OECD°TG°421) indicates the absence of selective

toxicity to the development at levels up to 36 mg/m3. No findings indicate any specific

developmental effects such as live birth index, viability index and apparent malformation. The

reported NOAEL(developmental) for 4,4 ́-methylenedicyclohexyl diisocyanate in a developmental toxicity

study according to OECD TG 414 (1, 6 and 36 mg/m3) is 6 mg/m3/day. At the 36 mg/m3level that

caused clear maternal respiratory tract toxicity (NOAEL(maternal) = 1 mg/m3) increased incidences of

ventricular septal defects of the heart and slight dilation of lateral brain ventricles were observed,

which lay marginally above the upper or within the normal range of scattering of the rat strain used

respectively.

Experience with human exposure

Eleven of 15 workers of a plant which has in 1981 established a new process to prevent glass

bottles from cracking by coating the bottles with polyurethane (4,4 ́-methylenedicyclohexyl

diisocyanate was used as monomer) suffered from several signs of an intoxication (Israeli, Smirnov

and Sculsky, 1981). All workers dealt for the first time with 4,4 ́-methylenedicyclohexyl

diisocyanate. The onset of the symptoms was observed 4 - 7 days after the exposure (no further

details available) and all workers recovered within 10 - 14 days. With the symptoms which were

recorded allergic and non-allergic skin reactions predominated (11/11). Six workers suffered from

vertigo with or without headaches and four developed a decrease of the obstructive lung function,

tachycardia and hypotension (EKG normal). The occupational hygiene with regard to ventilation

was described as insufficient but no air monitoring has been done.

Additional information relating to experience with human exposure is presented in Chapters 2.3 and

3.1.4.

Initial Assessment for Human Health

4,4 ́-Methylenedicyclohexyl diisocyanate is of low oral and dermal acute toxicity with an oral LD50

(rat) of 9900 mg/kg bw and a dermal LD50 (rabbit) > 10,000 mg/kg. Toxic symptoms after oral

administration included severe diarrhea, loss of appetite and increasing weakness. Assessment of

the acute inhalation toxicity data indicates that exposure to respirable aerosols of 4,4 ́-methylenedicyclohexyl diisocyanate confined predominantly to the respiratory tract. Clinical signs (salivation,

bradypnea, stridor) indicated respiratory distress. A hemorrhagic lung edema was considered to be

23
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

causative for mortality. An animal study according to OECD TG 403 gives a LC50 (4 h, rat) of

434 mg/m3.

4,4 ́-Methylenedicyclohexyl diisocyanate is moderately to severely irritant to the skin of rabbits

(OECD TG 404). Irritant effects were observed after instillation of 4,4 ́-methylenedicyclohexyl

diisocyanate into the eyes of rabbits (OECD TG 405). The repeated dose studies indicate that 4,4

 ́-methylenedicyclohexyl diisocyanate causes irritation of the respiratory tract.

Animal data are not uniform however they frequently provide evidence of a skin sensitizing

potential of 4,4 ́-methylenedicyclohexyl diisocyanate. Human case reports describe allergic contact

dermatitis due to 4,4 ́-methylenedicyclohexyl diisocyanate exposure. Although no validated animal

model is available to assess the potential for respiratory sensitization or asthma in humans animal

data support to some extent the hypothesis that respiratory hypersensitivity may be induced by 4,4

 ́-methylenedicyclohexyl diisocyanate.

No results from repeated-dose toxicity tests are available for the oral and dermal route of exposure.

A subacute inhalation study (1, 6 and 36 mg/m3; 6 hours/day on five days/week for 4 weeks) with

rats (OECD TG 412) indicates the respiratory tract to be the target organ of respirable 4,4

 ́-methylenedicyclohexyl diisocyanate aerosol. The reported NOAEL for effects governed by

respiratory tract irritation is 1 mg/m3; the LOAEL is 6 mg/m3 (i.e. histopathological changes in nasal

passages, larynx and bronchi). The results of a reproduction/developmental toxicity screening test

(OECD TG 421) corresponds to the results of the subacute study.

4,4 ́-Methylenedicyclohexyl diisocyanate did not induce gene mutations in bacteria

(OECD TG 471) and demonstrated no potential to induce chromosome aberrations in Chinese

hamster V79 cells in vitro (OECD TG 473) either with or without metabolic activation.

Data from an inhalative reproduction/developmental toxicity screening test according to

OECD TG 421 with rats (1, 6 and 36 mg/m3) did not reveal substance related impairment of

reproduction up to a 4,4 ́-methylenedicyclohexyl diisocyanate concentration of 6 mg/m3. A slightly

reduced fertility index was observed at an exposure level (36 mg/m3) that was associated with

parental toxicity. NOAELs were considered to be 1 mg/m3in males and females for general

toxicity. NOAEL for reproductive toxicity is 6 mg/m3.

Pre-natal inhalation toxicity testing in rats (OECD°TG°421) indicates the absence of selective

toxicity to the development at levels up to 36°mg/m3. No findings indicate any specific

developmental effects such as live birth index, viability index and apparent malformation. The

reported NOAEL(developmental) for 4,4 ́-methylenedicyclohexyl diisocyanate in a developmental toxicity

study according to OECD TG 414 (1, 6 and 36 mg/m3) is 6 mg/m3/day. At the 36 mg/m3level that

caused clear maternal respiratory tract toxicity (NOAEL(maternal) = 1 mg/m3) increased incidences of

ventricular septal defects of the heart and slight dilation of lateral brain ventricles were observed,

which lay marginally above the upper or within the normal range of scattering of the rat strain used

respectively.

4 HAZARDS TO THE ENVIRONMENT

Aquatic Effects

The inherent property of 4,4’-methylenedicyclohexyl diisocyanate is to hydrolyze in an aquatic

environment. In the following the toxicity of 4,4’-methylenedicyclohexyl diisocyanate and its

hydrolysis products is reported. Because of the rapid hydrolysis the assessment of the substance

24
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

should be based on the hydrolysis products and not on 4,4’-methylenedicyclohexyl diisocyanate.

Tests were conducted according to the GLP requirements and specially laid down test conditions.

Acute Toxicity Test Results

Concerning the acute toxicity of 4,4’-methylenedicyclohexyl diisocyanate and its hydrolysis

products towards aquatic species, experimental results for the three trophic levels (cf. Table 7) are

available. QSAR (EcoSar, version 0.99) calculations showed substantially lower EC/LCx values for

the main hydrolysis product, 4,4’-methylenebis(cyclohexylamine).

A static acute test with Danio rerio (formerly Brachydanio rerio) was conducted according to the

German UBA-proposal of 1984, which is in most parts equivalent to OECD TG 203. The test

solutions were treated in water with ultra-turrax at 8000 rpm for 60 seconds, before the animals

were added. Based on nominal concentration of 4,4’-methylenedicyclohexyl diisocyanate a 96 hLC50 of 1.2 mg/l (nominal) was obtained (Bayer AG, 1992). However, this test has not been taken

into account for the assessment of 4,4’-methylenedicyclohexyl diisocyanate. The aquatic half-life of

this isocyanate is approximately 2 hours. Possible aquatic emissions of the substance would enter a

wastewater treatment plant with a hydraulic retention time of several hydrolysis half-lives, which

means that virtually all isocyanate would hydrolyze before it enters environmental waters. Thus, for

assessment, not the isocyanate, but its hydrolysis product have to be tested. The hydrolysis product,

4,4’-methylenebis(cyclohexylamine), is the predominant form of the test substance in the following

tests:

Before beginning of the following studies with Danio rerio (formerly Brachydanio rerio), Daphnia

magna and Scenedesmus subspicatus pre-treatments were performed with 4,4’-methylenedicyclohexyl diisocyanate according to the recommendation mentioned in the “OECD Guidance

Document on aquatic toxicity testing of difficult substances and mixtures” in order to accelerate the

solution procedure. For that purpose the solutions of the test substance were prepared at a nominal

concentration that were 5fold higher than the maximum water solubility found for

4,4’-methylenedicyclohexyl diisocyanate in preliminary tests. The solutions were treated in water

with ultra-turrax 60 s/8000 rpm, afterwards stirred for 24 hours on a magnetic stirrer and finally

filtered. Because of the short half-life of 4,4’-methylenedicyclohexyl diisocyanate, testing with the

degradation products is required and has been conducted as seen in this test. Filtration removed

additional insoluble hydrolysis products. Substance concentrations (mainly the soluble hydrolysis

product 4,4’-methylenebis(cyclohexylamine)) were determined as TOC and back-calculated to the

parent compound.

Acute toxicity to fish (Danio rerio) has been investigated in a limit test under static conditions

according to Directive 92/69/EEC, C.1. A concentration of 30 mg/l 4,4’-methylenedicyclohexyl

diisocyanate was pretreated before start as described above. A 96 h-LC50 of > 8.1 mg/l (determined

as TOC and back-calculated to parent substance) was observed (Bayer AG, 2000b). At this

concentration level 10 % mortality was detected, however, in a range finding test no mortality

occurred at the highest concentration tested of 6 mg/l (nominal).

The hydrolysis product, 4,4’-methylenebis(cyclohexylamine), has a low ecotoxicity (LC50

(fish) = 38 mg/l) and was not classified as a PBT substance (EU PBT Working Group, 2003).

With the invertebrate Daphnia magna one acute static limit test in accordance with Directive

92/69/EEC, C.2, is available. For a test period of 48 hours an EC0 value of ≥ 8.3 mg/l (determined

as TOC and back-calculated to parent substance) was determined. At this concentration no mortality

was observed. A start concentration of 45 mg/l 4,4’-methylenedicyclohexyl diisocyanate was

treated for 24 h in the same way as described above (Bayer AG, 2000c).

25
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

Concerning the algal toxicity, a 72-hour test with Scenedesmus subspicatus was performed.

According to Directive 92/69/EEC, C.3, the growth inhibition of the alga species was investigated

with test substance concentrations in the range of 0.08 to 5 mg/l. The proceeding for preparation of

the stock solution was in the same way as described above (stirring and filtration). A 72 h-ErC50 of

> 5 mg/l (determined as TOC and back-calculated to parent substance) was determined. As the test

concentrations for the determination of the NOEC and LOEC were below the detection limit of the

TOC determination (2 mg/l), the test results of the algal toxicity study refer to nominal

concentrations. The arithmetic means of the TOC determination of the highest test concentration

(5 mg/l) exhibited an expected recovery rate (90 %) of the test substance based on organic C (Bayer

AG, 2000d).

Because of the short half-live of, testing with the degradation product is required for assessment.

The results of the aquatic toxicity testing on fish, Daphnia and algae of virtually completely

hydrolyzed 4,4’-methylenedicyclohexyl diisocyanate are compiled in Table 7 (all studies compiled

in this Table have a reliability of 1).

Table 7 Acute toxicity of hydrolyzed 4,4’-methylenedicyclohexyl diisocyanate to fish,

Daphnia and algae 

Species Test type Result Reference IUCLID

Brachydanio rerio

(fish)

Static, 96 h LC50 > 8.1 mg/l*

(10 % mortality rate)

Bayer

AG, 2000b

4.1

Daphnia magna

(crustacean)

Static, 48 h EC50 > 8.3 mg/l* Bayer

AG, 2000c

4.2

Scenedesmus subspicatus

(algae)

Static, 72 h ErC50 > 5 mg/l*

NOEC (cell density) = 0.31 mg/l (n)

LOEC (cell density) = 0.63 mg/l (n)

Bayer

AG, 2000d

4.3

*determined as TOC and back-calculated to the parent compound

(n) nominal concentration

Chronic Toxicity Test Results

Chronic data for aquatic toxicity of 4,4’-methylenedicyclohexyl diisocyanate are not available.

Determination of PNECaqua:

Since there are acute test results available for 4,4’-methylenedicyclohexyl diisocyanate and its

hydrolysis products from three trophic levels, an assessment factor of 1000 was applied for the

derivation of the PNECaqua according to the EU Technical Guidance Document. The lowest acute

tested concentration level was 5 mg/l for the alga species Scenedesmus subspicatus: 72 h-ErC50

> 5 mg/l (nominal) (Bayer AG, 2000d). This value was used to calculate the

PNECaqua > 5 μg/l

Toxicity to Microorganisms

Regarding the toxicity to microorganisms, an oxygen consumption inhibition test according to

Commission Directive 88/302/EEC, Part C (corresponds to the OECD TG 209) with activated

sewage sludge during 3 hours was performed and an EC50 of 191 mg/l (nominal) was determined

(Bayer AG, 2000e). Before testing a pre-treatment was performed with the test substance according

to the recommendation mentioned in the OECD Guidance Document on aquatic toxicity testing of

difficult substances and mixtures. 4,4’-Methylenedicyclohexyl diisocyanate was directly weighted

26
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

into water, treated by ultrasound for 3 - 4 hours and stirred overnight. This led to the nearly

complete hydrolysis of 4,4’-methylenedicyclohexyl diisocyanate and to the formation of the

hydrolysis product, 4,4’-methylenebis(cyclohexylamine).

The EU PBT Working Group (2003) reports that the hydrolysis product, 4,4’-methylenebis

(cyclohexylamine), has a low ecotoxicity (EC3 (bacteria) = 80 mg/l).

By an oxygen consumption inhibition test according to ISO 8192 with activated sewage sludge

during 3 hours, an EC50 of 19 mg/l (nominal) was determined under conditions which were not

relevant for assessment (Bayer AG, 1992).

Microbial toxicity of the hydrolysis products of 4,4’-methylenedicyclohexyl diisocyanate is

presented in Table 8.

Table 8 Toxicity of hydrolyzed 4,4’-methylenedicyclohexyl diisocyanate to

microorganisms

Species Endpoint Paramet

er

Effects Reference IUCLID

Activated sludge Inhibition of

respiration

3 h-EC50 191 mg/l (n) Bayer AG, 2000e 4.4

(n) nominal concentration

Terrestrial Effects

No data available.

Other Environmental Effects

No data available.

Initial Assessment for the Environment

4,4’-Methylenedicyclohexyl diisocyanate is a slightly yellowish, moisture/water sensitive liquid

with a melting point of 15 °C. 4,4’-Methylenedicyclohexyl diisocyanate has a relative density of

1.07 at 25 °C, a boiling point of 167 - 168 °C (at 2 hPa), and a vapor pressure of 2.13 x 10-5 hPa at

25 °C [Directive 92/69/EEC, A.4]. A water solubility and a log KOW are not determinable due to the

instability of 4,4’-methylenedicyclohexyl diisocyanate in water. The flash point of

4,4’-methylenedicyclohexyl diisocyanate is 200 °C [DIN 51758], the ignition point is 225 °C and

the viscosity is approximately 30 mPa x s at 25 °C [DIN ISO EN 3219/A.3]. The calculated half-life

of 4,4’-methylenedicyclohexyl diisocyanate in air due to indirect photodegradation is about 15.0 h.

4,4’-Methylenedicyclohexyl diisocyanate hydrolyses rapidly in the presence of water, the major

product in aqueous phase is 4,4’-methylenebis(cyclohexylamine). In water, a half-life for

4,4’-methylenedicyclohexyl diisocyanate of approximately 2 hours was determined experimentally.

Due to the rapid hydrolysis of 4,4’-methylenedicyclohexyl diisocyanate, a transport of the substance

between environmental compartments is unlikely. Consequently, a calculation of the Henry Law

Constant and of the distribution between the environmental compartments according to the Mackay

fugacity model level 1 is not suitable.

27
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

However, several aquatic toxicity tests have been undertaken with 4,4’-methylenedicyclohexyl

diisocyanate and its hydrolysis products. Because of the rapid hydrolysis the assessment of the

substance should be based on the hydrolysis products and not on 4,4’-methylenedicyclohexyl

diisocyanate. The hydrolysis product 4,4’-methylenebis(cyclohexylamine) was assessed by the EU

PBT Working Group. The hydrolysis product was not classified as a PBT substance.

4,4’-Methylenedicyclohexyl diisocyanate is not readily biodegradable.

Due to the rapid hydrolysis 4,4’-methylenedicyclohexyl diisocyanate is neither persistent in the

water compartment nor bioaccumulative. The calculated Koc-value indicates that 4,4’-methylenedicyclohexyl diisocyanate may strongly adsorb to soil but due to its rapid hydrolysis any emission to

the terrestrial compartment would be affected by humidity and therefore, geoaccumulation of

4,4’-methylenedicyclohexyl diisocyanate is not expected to occur.

Concerning the toxicity of 4,4’-methylenedicyclohexyl diisocyanate and its hydrolysis products

towards aquatic species, reliable experimental results of tests with fish, Daphnia, and algae are

available (* = determined as TOC and back-calculated to parent substance, n = nominal

concentration).

Danio rerio (fish): 96 h-LC50 > 8.1 mg/l*, [Directive 92/69/EEC, C.1]

Daphnia magna (aq. invertebrate): 48 h-EC50 > 8.3 mg/l*, [Directive 92/69/EEC, C.2]

Scenedesmus subspicatus (algae): 72 h-ErC50 > 5 mg/l*, [Directive 92/69/EEC, C.3]

Activated sewage sludge (bacteria): 3 h-EC50 = 191 mg/l (n), [Directive 88/302/EEC, Part C 

(corresponds to the OECD TG 209)].

It has to be considered that the toxicity observed in the reported aquatic studies was caused both by

the 4,4’-methylenedicyclohexyl diisocyanate as well as by the hydrolysis products due to the

instability of the test substance.

Based on the acute aquatic toxicity data on three trophic levels (fish, Daphnia, algae), the Predicted

No Effect Concentration (PNECaqua) can be calculated with an assessment factor of 1000 applied to

the lowest acute effect concentration. The lowest 72 h-ErC50-value of > 5 mg/l obtained for the alga

species Scenedesmus subspicatus was used to derive a PNECaqua of > 5 μg/l.

5 RECOMMENDATIONS

Human Health:

The chemical possesses properties indicating a hazard for human health (severe irritation of skin,

eye and respiratory tract, sensitization of skin and predicted to be a respiratory tract sensitizer

because it is a diisocyanate). Based on data presented by the Sponsor country (relating to

production by one producer which accounts for approximately 5 % to 50 % of global production

and relating to the use pattern in several OECD countries), occupational exposure is anticipated to

be low and there are no known consumer uses. Therefore this chemical is currently of low priority

for further work. Countries may desire to investigate any exposure scenarios that were not presented

by the Sponsor country.

Environmental:

The chemical (including its hydrolysis products) possesses properties indicating a hazard for the

environment. Based on data presented by the Sponsor country (relating to production by one

producer which accounts for approximately 5 % to 50 % of global production and relating to the use

28
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

pattern in several OECD countries), exposure to the environment is anticipated to be low, and

therefore this chemical is currently of low priority for further work. Countries may desire to

investigate any exposure scenarios that were not presented by the Sponsor country. The chemical is

currently of low priority for further work.

29
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

6 REFERENCES

American Cyanamid Company (1984). Initial submission: A closed-patch repeated insult dermal

sensitization study in guinea pigs with toluene diisocyanate and others with cover letter dated

051592; Auletta, CS and Daly IW. Bio/dynamics Inc. Project No. 4971-84 December 20, 1984

NTIS/OTS 539513, Doc I.D. 88-920002754 (1992).

Bayer AG (1979). Desmodur W, Flammpunkt. Unpublished Report 79/0219 (511067), 1979-12-01.

Bayer AG (1981a). Bericht ueber die Pruefung von Dicyclohexylmethan-4,4-diisocyanat fluessig

auf primaere Hautreizwirkung. Schreiber G, Fraunhofer Inst (FHG) April 02, 1981 and Mobay

Corp (1981). The evaluation of liquid dicyclohexylmethane-4,4 ́-diisocyanate for primary skin

irritation in rabbits with cover letter dated 072987 NTIS/OTS 515391 Doc I.D. 86-870001232

(1987).

Bayer AG (1981b). Bericht ueber die Pruefung von Dicyclohexylmethan-4,4-diisocyanat fest auf

primaere Hautreizwirkung. Schreiber G, Fraunhofer Inst (FHG) April 02, 1981 and Mobay Corp

(1981). Bericht ueber die Pruefung von Dicyclohexylmethan-4,4-diisocyanat fest auf primaere

Hautreizwirkung (HMDI) with cover letter dated 072987 NTIS/OTS 515393 Doc I.D. 86-

870001234 (1987).

Bayer AG (1981c). Bericht ueber die Pruefung von Dicyclohexylmethan-4,4-diisocyanat fluessig

auf Schleimhautreizwirkung. Schreiber G, Fraunhofer Inst (FHG) April 02, 1981 and Mobay Corp.

(1981). Bericht ueber die Pruefung von Dicyclohexylmethan-4,4-diisocyanat fluessig auf

Schleimhautreizwirkung with cover letter dated 072987 NTIS/OTS 515390 Doc I.D. 86-870001231

(1987).

Bayer AG (1981d) Bericht ueber die Pruefung von Dicyclohexylmethan-4,4-diisocyanat fest auf

Schleimhautreizwirkung. Schreiber G, Fraunhofer Inst. (FHG) April 02, 1981 and Mobay Corp.

(1981). The evaluation of solid dicyclohexylmethane-4,4 ́-diisocyanate for mucous membrane

irritation in rabbits with cover letter dated 072987 NTIS/OTS 515392 Doc I.D. 86-870001233

(1987).

Bayer AG (1984). Schmidt WM 4,4-Diisocyanato-dicyclohexylmethan (H-MDI), Untersuchungen

zur sensibilisierenden Wirkung an der Meerschweinchenhaut (modif. Maximierungstest mit nur

intrakutaner Induktion). Report No. 13039, November 15, 1984.

Bayer AG (1985). Schmidt WM 4,4-Diisocyanato-dicyclohexylmethan (H-MDI), Prüfung auf

sensibilisierende Wirkung an der Meerschweinchenhaut (Maximierungstest nach Magnusson/

Klingman). Report No. 13787, August 29, 1985.

Bayer AG (1992). Determination on the ecological behaviour of Desmodur W. Unpublished Report

218 A/90, 1992-05-29.

Bayer AG (1994a). Desmodur W, Abschlußbericht Dampfdruck. Unpublished Report 94/121 A,

1994-10-11.

Bayer AG (1994b). Kroetlinger F. Desmodur W, study for skin irritation/corrosion in rabbits.

Report No. 22868, February 2, 1994.

Bayer AG (1995a). Pauluhn J. Untersuchungen zur akuten Inhalationstoxizitaet an der Ratte nach

OECD-No. 403. Report No. 24490, November 20, 1995.

Bayer AG (1995b). Pauluhn J. Desmodur W, Pilot study for lung sensitization in Guinea-pigs

following intradermal induction. Report No. 24199, July 26, 1995.

30
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

Bayer AG (1999). Decrease of NCO-Content in Water. Unpublished Report N 99/0049/01 LEV,

1999-05-14.

Bayer AG (2000a). MR-Test. Unpublished Report 858 A/99 R, 2000-01-10.

Bayer AG (2000b). Fish test. Unpublished Report 858 A/99 F, 2000-01-07.

Bayer AG (2000c). Daphnia test. Unpublished Report 858 A/99 D, 2000-01-06.

Bayer AG (2000d). Algal test. Unpublished Report 858 A/99 Al, 2000-01-06.

Bayer AG (2000e). Toxicity to bacteria. Unpublished Report 858 A/99 B, 2000-01-17.

Bayer Corporation (1996). Acute dermal irritation corrosive study in rabbits in Desmodur W.

Wakefiled A Corning Hazleton (CHV) CHV Study No. 17568, July 17, 1996.

Bayer Industry Services (2003). Desmodur W/4,4'methylenedicyclohexyl diisocyanate CAS: 5124-

30-1, Request of Delisting. 2003-01-24.

Bayer Industry Services (2004a). Desmodur W. Calculation of 

- Indirect Photodegradation with AOPWIN v1.91, 2000.

- Soil Adsorption Coefficient with PCKOCWIN v1.66, 2000.

Bayer Industry Services (2004b). Hydrolysis as a function of pH and temperature of Desmodur W.

Results of preliminary test. Unpublished Report A04/0044/01 LEV, 2004-09-23.

Bayer MaterialScience AG (2004a). Desmodur W - Internal Data on Production, Processing, Use

Pattern, and Workplace Exposure (unpublished).

Bayer MaterialScience AG (2004b). Safety Data Sheet Desmodur W. No. 028979/08, 2004-03-10.

Bayer MaterialScience AG (2004c). Pauluhn J. Pilot-subacute inhalation toxicity on rats. Report

No. AT00392, May 02, 2004, unpublished.

Bayer MaterialScience AG (2004d). Pauluhn J. Subacute inhalation toxicity on rats. Report No.

AT01057, March 08, 2004, unpublished.

Bayer MaterialScience AG (2004e). Eiben R, Rosenbruch M. Desmodur W, Reproduction/

Developmental Toxicity Screening Test in rats. Report No. AT01096, March 19, 2004,

unpublished.

Bayer MaterialScience AG (2004f). Herbold B. Desmodur W, in vitro chromosome aberration test

with Chinese hamster V79 cells. Report No. AT01132, April 08, 2004, unpublished.

Bayer MaterialScience AG (2004g). Langewische FW. Developmental toxicity study in rats after

inhalation. Report No. AT01218, May 24, 2004, unpublished.

Bayer MaterialScience AG (2005) Wirnitzer U Desmodur W Salmonella/Microsome Test Plate

Incoporation and Preincubation Method Report No. AT01757; January 13, 2005, unpublished.

Dearman RJ, Basketter DA, Kimber I (1992). Variable effects of chemical allergens on serum IgE

concentration in mice. Preliminary evaluation of a novel approach to the indentification of

respiratory sensitizers. J. Appl. Toxicol. 12l, 317-323.

Dearman RJ, Spence LM, Kimber I (1992). Characterization of murine immune responses to

allergenic diisocyanates. Toxicol. Appl. Pharmacol. 112, 190-197 and ICI Americas Inc. (1991).

Characterization of murine immune responses to allergenic diisocyanates with attachments and

cover letter dated 100891. NTIS/OTS533621 Doc I.D. 86-920000055 (1991).

31
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

Dieterich D, Uhlig K (2002). Polyurethanes. Ullmann's Encyclopedia of Industrial Chemistry

(electronic release). Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

DuPont De Nemours (1977). Mutagenic activity of isocyanic acid, methylenebis-(4-cyclohexyl)

ester in the Salmonella/Microsome assay. Russell JF Haskell Laboratory Report No. 428-77 June

10, 1977; NTIS/OTS 516971, Doc I.D. 86-870001068 (1988).

Emmett EA (1976). Allergic contact dermatitis in Polyurethane plastic moulders. J. Occup. Med.

18, 802-804.

EU PBT Working Group (2003). European Chemicals Bureau PBT list no. 20. 4,4'-methylenedicyclohexyl diisocyanate (including EU ECB IUCLID of Feb. 11, 2000). Paris.

Frick M, Bjoerkner B, Hamnerius N, Zimerson E (2003). Allergic contact dermatitis from

dicyclohexylmethane- 4,4'-diisocyanate. Cont. Dermat. 48, 305-309.

GIAP (State Scientific-Research and Design Institute of the Nitrogen Industry, USSR) (1969).

Procédé de préparation d'isocyanates organiques. Patent France 1.578.808.

Henriks-Eckerman M-L, Vaelimaa J, Rosenberg C, Peltonen K, Engstroem K (2002). Expsure to

airborne isocyanates and other thermal degradation products at polyurethane-processing

workplaces. J. Environ. Monit. 4, 717-721.

Hoffman TE (1982) Allergic Contact Dermatitis to new plastic resins. Arch Dermatol 118, 962.

Israeli R, Smirnov V, Sculsky M (1981). Vergiftungserscheinungen bei Dicyclohexyl-methan4,4'-diisocyanat-Exposition (Intoxication due to dicyclohexyl-methane-4,4'-diisocyanate exposure).

Int. Arch. Occu. Environ. Health 48 (2), 179-184.

Karol MH, Magreni C (1982). Extensive skin sensitization with minimal antibody production in

Guinea pigs as a result of exposure to dicyclohexylmethane-4,4'-diisocyanate. Toxicol. Appl.

Pharmacol. 65, 291-301 and Dow Chemical Co. (1992). Initial submission: Sensitivity to

dicyclohexylmethane diisocyanate with cover letter dated 050792, NTIS/OTS 537254 Doc I.D. 88-

92002444 (1992).

King CM (1980). Contact sensitivity to Hylene W. Cont. Dermat. 6, 353-354.

Lewis FA (1980). NIOSH Health Hazard Evaluation Determination Report Number 79-141-711,

Fischer and Porter Company, Warminster, Pennsylvania. US NIOSH, PB81-167918, 13 pp. 

Litz N (1990). Schutz vor weiteren anthropogenen Organika-Einträgen. In: Blume H-P (ed.):

Handbuch des Bodenschutzes. Bodenoekologie und –belastung; Vorbeugende und abwehrende

Schutzmassnahmen. Ecomed-Verlag Landsberg / Lech. 581. 

Malten KE (1977). 4,4'-Diisodyanato dicyclohexyl methane (Hylene W): a strong contact sensitizer.

Cont. Dermat. 3, 344-346.

Mobay Chemical Corp. (1984). Sensory irritation of Desmodur W to mice. Sangha GK Study

Number 82-341-03 Report No. 479, May 3, 1984 and Mobay Chemical Corp. (1987). Sensory

irritation of Desmodur W to mice with cover letter dated 072987 NTIS/OTS 515436, Doc I.D. 86-

870001277 (1987).

Mobay Chemical Corp. (1985). Acute inhalation study with dicyclohexylmethane 4,4-diisocyanate

(Desmodur W) in rats. Sangha GK Study Number 82-041-05 Report No. 642, July 15, 1985 and

Mobay Chemical Corp. (1985). Acute inhalation study with dicyclohexylmethane 4,4-diisocyanate

32
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

(Desmodur W) in rats with cover letter dated 080687 NTIS/OTS 515395, Doc I.D. 86-870001236

(1987).

Monsanto Co. (1966). Toxicological investigation of: 4,4 ́-diisocyanato dicyclohexyl methane.

Younger FM Younger Laboratories Monsanto Project Number YO-66-107 June 9, 1966 NTIS/OTS

555173, Doc I.D. 88-920008675 (1992).

NIOSH (2004). http://www.cdc.gov/niosh/npg/npgd0412.html (Pocket Guide to Chemical

Hazards); U.S.A.

Six C, Richter F (2003). Isocyanates, Organic, 4. Production. Ullmann's Encyclopedia of Industrial

Chemistry. Electronic release. Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

SPIN (2004). Substances in Preparations in Nordic Countries. www.spin2000.net/spin.html.

Stadler JC, Karol MH (1984). Experimental delayed hypersensitvity following inhalation of

Dicyclohexylmethane-4,4'-diisocyanate: a concentration-response relationship. Toxicol Appl

Pharmacol 74, 244-249.

Stadler JC, Karol MH (1985). Use of dose-response data to compare the skin sensitizing abilities of

dicyclohexylmethane-4,4'-diisocyanate and picryl chloride in two animal species. Toxicol. Appl.

Pharmacol. 78, 445-450. 

Swiss Product Register (2004). Personal communication to BUA, Juli 2004.

Thompson T, Belisito DV (1997). Allergic contact dermatitis from a diisocyanate in wool

processing. Cont. Dermat. 37, 239.

Thorne PS, Hillebrand JA, Lewis GR, Karol MH (1987). Contact sensitivity by diisocyanates:

potencies and cross-reactivities. Toxicol. Appl. Pharmacol. 87, 155-165.

TRGS 402 (1997). Technische Regeln für Gefahrstoffe 402: Ermittlung und Beurteilung der

Konzentrationen gefaehrlicher Stoffe in der Luft in Arbeitbereichen http://www.baua.de/prax/

ags/trgs402.pdf.

TRGS 430 (2004). Isocyanate –Exposition und Ueberwachung http://www.baua.de/prax/index.htm

TRGS 900 (2004). Technische Regeln für Gefahrstoffe 900: Limit values relating to air in the

workplace, http://www.baua.de/prax/ags/trgs900.pdf.

US EPA (US Environmental Protection Agency) (2005). EPIWIN program (EPI suite) calculation

for 4,4’-methylenebis(cyclohexylamine) (CAS 1761-71-3).

http://www.epa.gov/opptintr/exposure/docs/episuitedl.htm (for program download).

Weyel DA, Schaffer RB (1985). Pulmonary and sensory irritation of diphenylmethane-4,4'- and

dicyclohexylmethane-4,4'-diisocyanate. Toxicol. Appl. Pharmacol. 77, 427-433.

White IR, Stewart JR, Rycroft RJ (1983). Allergic contact dermatitis from an organic di-isocyanate.

Cont. Dermat. 9, 300-303

White R (1982). Allergisches Kontakt-Ekzem aufgrund eines organischen Di-isocyanats. Beitrag

zum Kolloquium zu den Orientierungsgrundsaetzen der Forschung im Bereich der Industriellen

Toxikologie, Nancy 27.-29.09.1982: 22-23.

Zhuravlev EZ (1976). Flash and ignition points of certain organic isocyanates. J. Appl. Chem.

USSR (Engl. Transl.) 49, 90-94.

33
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

Zissu D, Binet S, Limasset JC (1998). Cutaneous sensitization to some polyisocyanate prepolymers

in Guinea pigs. Cont. Dermat. 39, 248-251.

34
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

S I D S

Dossier

Existing Chemical : ID: 5124-30-1

CAS No. : 5124-30-1

EINECS Name : 4,4'-methylenedicyclohexyl diisocyanate

EC No. : 225-863-2

Molecular Weight : 262.35 g/mol

Molecular Formula : C15H22N2O2

Producer related part

Company : Bayer AG

Creation date : 08.12.1994

Substance related part

Company : Bayer AG

Creation date : 08.12.1994

Status :

Memo :

Printing date : 09.11.2006

Revision date : 12.02.1997

Date of last update : 09.11.2006

Number of pages : 130

Chapter (profile) : Chapter: 1, 2, 3, 4, 5, 6, 7, 8, 10

Reliability (profile) : Reliability: without reliability, 1, 2, 3, 4

Flags (profile) : Flags: without flag, non confidential, WGK (DE), TA-Luft (DE), Material

Safety Dataset, Risk Assessment, Directive 67/548/EEC, SIDS

35
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

1. GENERAL INFORMATION ID: 5124-30-1

DATE: 09.11.2006

1.0.1 APPLICANT AND COMPANY INFORMATION

1.0.2 LOCATION OF PRODUCTION SITE, IMPORTER OR FORMULATOR

1.0.3 IDENTITY OF RECIPIENTS

1.0.4 DETAILS ON CATEGORY/TEMPLATE

1.1.0 SUBSTANCE IDENTIFICATION

IUPAC Name : 1,1 ́-methylenebis(4-isocyanatocyclohexane)

Smiles Code : O=C=NC(CCC(C1)CC(CCC(N=C=O)C2)C2)C1

Molecular formula : C15 H22 N2 O2

Molecular weight : 262.35 g/mol

Petrol class :

Remark : IUPAC name was generated by ICS naming system (http://by-cis.bayerag.com:81/icsweb/naming/naming_single)

Flag : Critical study for SIDS endpoint

02.01.2006 (93)

1.1.1 GENERAL SUBSTANCE INFORMATION

Purity type : typical for marketed substance

Substance type : organic

Physical status : liquid

Purity : 100 % w/w

Colour : light yellowish

Odour : slight lachrymatory odour

Remark : 100 % purity relates to the usuable components of the product (isomers of

4,4'-methylenedicyclohexyl diisocyanate and 2,4'-methylenedicyclohexyl

diisocyanate)

Flag : Critical study for SIDS endpoint

22.11.2004 (32)

Remark : As long as not otherwise stated, the isomers mixture of 92 % 4,4 ́-isomers

and 8 % 2,4 ́-isomers is meant

Result : The approximate isomeric composition of the pure industrial product is: 

4,4'-methylenedicyclohexyl diisocyanate (in total 92 %)

- cis,cis-isomer 14 %

- cis,trans-isomer 58 %

- trans,trans-isomer 20 %

- others 8 % (2,4'-methylenedicyclohexyl diisocyanate)

Flag : Critical study for SIDS endpoint

14.12.2005 (45)

36
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

1. GENERAL INFORMATION ID: 5124-30-1

DATE: 09.11.2006

1.1.2 SPECTRA

1.2 SYNONYMS AND TRADENAMES

1,1-Methylenebis(4-isocyanatocyclohexane)

Flag : Critical study for SIDS endpoint

10.09.2004 (4) (45)

4,4'-Dicyclohexylmethanediisocyanate

Flag : Critical study for SIDS endpoint

10.09.2004 (4)

4,4'-Diisocyanatodicyclohexylmethane

Flag : Critical study for SIDS endpoint

10.09.2004 (45)

4,4'-Methylenebis(cyclohexyl isocyanate)

Flag : Critical study for SIDS endpoint

10.09.2004 (4)

Bis(4-isocyanatocyclohexyl)methane

Flag : Critical study for SIDS endpoint

10.09.2004

Cyclohexane, 1,1'-methylenebis(4-isocyanato)-

Remark : CAS name

Flag : Critical study for SIDS endpoint

16.09.2004 (4)

Desmodur W

Flag : Critical study for SIDS endpoint

(45)

Dicyclohexylmethane-4,4'-diisocyanate

Flag : Critical study for SIDS endpoint

10.09.2004 (4)

H12MDI

Flag : Critical study for SIDS endpoint

10.09.2004 (84)

Hydrogenated MDI

Flag : Critical study for SIDS endpoint

10.09.2004 (4)

Hylene W

37
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

1. GENERAL INFORMATION ID: 5124-30-1

DATE: 09.11.2006

Flag : Critical study for SIDS endpoint

25.11.2004

Methylene bis(4-isocyanatocyclohexane)

Flag : Critical study for SIDS endpoint

10.09.2004

Methylenebis(1,4-cyclohexylene) diisocyanate

Flag : Critical study for SIDS endpoint

10.09.2004

Methylenedi-1,4-cyclohexylene isocyanate

Flag : Critical study for SIDS endpoint

10.09.2004

Methylenedi-4-cyclohexylene diisocyanate

Flag : Critical study for SIDS endpoint

10.09.2004 (4)

1.3 IMPURITIES

Purity : typical for marketed substance

CAS-No :

EC-No :

EINECS-Name :

Molecular formula :

Value : 

Remark : no impurities reported

22.11.2004

1.4 ADDITIVES

1.5 TOTAL QUANTITY

Quantity : 1000 - 5000 tonnes produced in 2003

Remark : The global production capacity of 4,4'-methylenedicyclohexyl diisocyanate

is 10,000-20,000 tonnes/a, with most of it in the USA. In Germany, Bayer

MaterialScience AG is the only producer and has a manufacturing capacity

of 1,000-5,000 tonnes/a of 4,4'-methylenedicyclohexyl diisocyanate.

Flag : Critical study for SIDS endpoint

22.11.2004 (31)

1.6.1 LABELLING

Labelling : as in Directive 67/548/EEC

38
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

1. GENERAL INFORMATION ID: 5124-30-1

DATE: 09.11.2006

Specific limits :

Symbols : T, , , 

Nota : , , 

R-Phrases : (23) Toxic by inhalation

(36/37/38) Irritating to eyes, respiratory system and skin

(42/43) May cause sensitization by inhalation and skin contact

S-Phrases : (26) In case of contact with eyes, rinse immediately with plenty of water

and seek medical advice

(28) After contact with skin, wash immediately with plenty of water

(38) In case of insufficient ventilation, wear suitable respiratory equipment

(45) In case of accident or if you feel unwell, seek medical advice

immediately (show the label where possible)

1.6.2 CLASSIFICATION

Classified : as in Directive 67/548/EEC

Class of danger : irritating

R-Phrases : (36/37/38) Irritating to eyes, respiratory system and skin

Specific limits :

Classified : as in Directive 67/548/EEC

Class of danger : sensitizing

R-Phrases : (42/43) May cause sensitization by inhalation and skin contact

Specific limits :

Classified : as in Directive 67/548/EEC

Class of danger : toxic

R-Phrases : (23) Toxic by inhalation

Specific limits :

1.6.3 PACKAGING

1.7 USE PATTERN

Type of use : type

Category : Non dispersive use

Flag : Critical study for SIDS endpoint

22.11.2004 (85)

Type of use : industrial

Category : Chemical industry: used in synthesis

Remark : Used for the manufacture of rubber and plastic products, industrial paints,

chemical products, construction and transport equipment

Flag : Critical study for SIDS endpoint

22.11.2004 (85)

39
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

1. GENERAL INFORMATION ID: 5124-30-1

DATE: 09.11.2006

Type of use : use

Category : Intermediates

Remark : 4,4'-Methylenedicyclohexyl diisocyanate is registered as a component in

approximately 50 industrial products in the Danish, Finnish, and Swedish

Product Registers with a consumption of about 30 tonnes/a in 2000 and

2001 (last years of record). There is no registration for a consumer product.

It is confidentially listed in the Norwegian Product Register. The main use

category is "non-dispersive use".

Flag : Critical study for SIDS endpoint

22.11.2004 (85)

Type of use : use

Category : Intermediates

Remark : The Swiss Product Register lists 34 industrial products (with concentrations

of up to 100 % 4,4'-methylenedicyclohexyl diisocyanate), but no consumer

product containing 4,4'-methylenedicyclohexyl diisocyanate.

The following industrial product categories were reported:

auxiliary material; cleaning agent; glue, surfacer, cement; sealing mass;

hardener; paints, dyes, lacquers; plastic molding

Flag : Critical study for SIDS endpoint

22.11.2004 (89)

1.7.1 DETAILED USE PATTERN

1.7.2 METHODS OF MANUFACTURE

1.8 REGULATORY MEASURES

1.8.1 OCCUPATIONAL EXPOSURE LIMIT VALUES

Type of limit : MAK (DE)

Limit value : .054 mg/m3

Short term exposure limit value

Limit value :

Time schedule : 8 hour(s)

Frequency : times

Remark : Mean for 8 h shift

Flag : Critical study for SIDS endpoint

22.11.2004 (32)

1.8.2 ACCEPTABLE RESIDUES LEVELS

1.8.3 WATER POLLUTION

Classified by : other: Bayer AG

Labelled by :

40
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

1. GENERAL INFORMATION ID: 5124-30-1

DATE: 09.11.2006

Class of danger : 1 (weakly water polluting)

Remark : Identification no. 6724.

Class of danger: according to VwVwS Appendix 3

21.12.2004 (32)

1.8.4 MAJOR ACCIDENT HAZARDS

Legislation : Stoerfallverordnung (DE)

Substance listed : yes

No. in Seveso directive :

Remark : Reported in Appendix II Nr. 4 c; III Teil 2 Kat. 2; IV Kat. 2

("giftige Stoffe")

23.06.1998

1.8.5 AIR POLLUTION

Classified by : other: Bayer AG

Labelled by :

Number : other: TA-Luft 5.2.5 organic substances

Class of danger : I

22.11.2004 (32)

1.8.6 LISTINGS E.G. CHEMICAL INVENTORIES

1.9.1 DEGRADATION/TRANSFORMATION PRODUCTS

Type : degradation product in water

CAS-No : 1761-71-3

EC-No : 217-168-8

EINECS-Name : 4,4'-methylenebis(cyclohexylamine)

IUCLID Chapter : 3.1.2

16.09.2004 (29)

1.9.2 COMPONENTS

1.10 SOURCE OF EXPOSURE

1.11 ADDITIONAL REMARKS

1.12 LAST LITERATURE SEARCH

Type of search : Internal and External

Chapters covered : 1

41
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

1. GENERAL INFORMATION ID: 5124-30-1

DATE: 09.11.2006

Date of search : 13.08.2003

16.09.2004

Type of search : Internal and External

Chapters covered : 2

Date of search : 13.08.2003

16.09.2004

Type of search : Internal and External

Chapters covered : 3, 4

Date of search : 13.08.2003

Remark : Last literature search for Chapter 3.2.1 27-JUL-2004

16.09.2004

Type of search : Internal and External

Chapters covered : 5

Date of search : 22.01.2003

Remark : Human Health: last literature search January 22, 2003: CAS number

search in external and internal databases, e.g. Biosis, Embase, Toxline,

Scisearch

14.09.2004

1.13 REVIEWS

42
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

2. PHYSICO CHEMICAL DATA ID: 5124-30-1

DATE: 09.11.2006

2.1 MELTING POINT

Value : 15 °C

Sublimation :

Method : other: no data 

Year : 2004

GLP : no data

Test substance : other TS: 4,4'-Methylenedicyclohexyl diisocyanate, purity: 92 %

Result : The melting point of the isomeric mixture of 4,4'-methylenedicyclohexyl

diisocyanate (cis, cis-isomer: 14 %; cis, trans-isomer: 58 % and trans,

trans-isomer: 20 %, 8 % 2,4-isomers) is 15 °C.

The melting point of 4,4'-methylenedicyclohexyl diisocyanate is 83 °C.

Reliability : (2) valid with restrictions

Data from peer-reviewed handbook or collection of data

Flag : Critical study for SIDS endpoint

19.09.2004 (45)

Value : < -10 °C

Sublimation :

Method : other: no data 

Year : 2004

GLP : no data

Test substance : other TS: 4,4'-Methylenedicyclohexyl diisocyanate, no purity specified

Remark : Freezing point. No information supplied on the isomeric composition of the

substance

Reliability : (2) valid with restrictions

Data from handbook or collection of data

19.09.2004 (78)

Value : 49.8 °C

Sublimation :

Method : other: no data 

Year : 1975

GLP : no

Test substance : other TS: 4,4'-Methylenedicyclohexyl diisocyanate, purity not below 99.9 %

Remark : A sample of 4,4'-methylenedicyclohexyl diisocyanate having a melting point

of 49.8 +/- 0.2 °C was used for different investigations concerning

physicochemical properties.

No information supplied on the isomeric composition of the substance

Reliability : (2) valid with restrictions

Basic data given

22.11.2004 (99)

Value : = 78 °C

Sublimation :

Method : other: no data 

Year : 1971

GLP : no

Test substance : other TS: trans, trans-4,4'-Methylenedicyclohexyl diisocyanate, no purity

specified

Result : The solidification point of crystalline trans,trans-4,4'-methylenedicyclohexyl

diisocyanate is 78 °C

Reliability : (2) valid with restrictions

43
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

2. PHYSICO CHEMICAL DATA ID: 5124-30-1

DATE: 09.11.2006

Basic data given

04.11.2005 (40) (74)

Value : = 80 °C

Sublimation :

Method : other: no data 

Year : 1968

GLP : no

Test substance : other TS: trans, trans-4,4'-Diisocyanatodicyclohexylmethane, no purity

specified

Remark : trans,trans-4,4'-Methylenedicyclohexyl diisocyanate is prepared by reacting

a carbon dioxide-4,4'-methylenebis(cyclohexylamine)-adduct (contains

95% w/w of the trans,trans-isomer) with phosgene

Reliability : (2) valid with restrictions

Basic data given

10.05.2004 (5) (40)

Value : 81.5 82 °C

Sublimation :

Method : other: no data 

Year : 1965

GLP : no

Test substance : other TS: trans, trans-4,4'-Methylenedicyclohexyl diisocyanate, purity: 98%

Reliability : (2) valid with restrictions

Data from peer-reviewed handbook or collection of data

04.11.2005 (40)

Value : ca. 25 °C

Sublimation :

Method : other: no data 

Year :

GLP : no data

Test substance : as prescribed by 1.1 - 1.4

Remark : Point of solidification

Reliability : (4) not assignable

Manufacturer data without proof

23.11.2004 (32)

Value : 19 23 °C

Sublimation :

Method : other: no data 

Year : 2004

GLP : no data

Test substance : other TS: 4,4'-Methylenedicyclohexyl diisocyanate, no purity specified

Remark : No information given on isomeric composition of mixture

Reliability : (4) not assignable

Data from non peer-reviewed handbook or collection of data

19.09.2004 (92)

Value : 60 71 °C

Sublimation :

Method : other: no data 

Year : 1977

GLP : no

Test substance : other TS: 4,4'-Methylenedicyclohexyl diisocyanate, no purity specified

44
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

2. PHYSICO CHEMICAL DATA ID: 5124-30-1

DATE: 09.11.2006

Remark : No information given on isomeric composition of mixture

Reliability : (4) not assignable

Manufacturer data without proof

19.09.2004 (6)

2.2 BOILING POINT

Value : 167 168 °C at 2 hPa

Decomposition :

Method : other: no data 

Year : 1969

GLP : no

Test substance : other TS: 4,4'-Methylenedicyclohexyl diisocyanate, no purity specified

Remark : No information given on isomeric composition of mixture. The British patent

1.173.890 is the English (British) version of the French patent 1.578.808

Reliability : (2) valid with restrictions

Basic data given

Flag : Critical study for SIDS endpoint

19.09.2004 (60) (81) (88)

Decomposition :

Method : other: no data 

Year :

GLP : no data

Test substance : as prescribed by 1.1 - 1.4

Remark : Not measurable (decomposition) at standard pressure

Reliability : (4) not assignable

Manufacturer data without proof

02.11.2005 (32)

Value : 155 160 °C at .67 hPa

Decomposition :

Method : other: no data 

Year : 1965

GLP : no

Test substance : other TS: trans, trans-4,4'-Methylenedicyclohexyl diisocyanate, purity: 92 %

Reliability : (2) valid with restrictions

Basic data given

04.11.2005 (40)

2.3 DENSITY

Type :

Value : 1.07 at 25 °C

Method : other: no data 

Year : 2004

GLP : no data

Test substance : other TS: 4,4'-Methylenedicyclohexyl diisocyanate, no purity specified

Remark : No information supplied on the isomeric composition of the substance

Reliability : (2) valid with restrictions

Data from handbook or collection of data

45
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

2. PHYSICO CHEMICAL DATA ID: 5124-30-1

DATE: 09.11.2006

Flag : Critical study for SIDS endpoint

19.09.2004 (78)

Type : density

Value : 1.0058 g/cm3 at 55 °C

Method : other: no data 

Year : 1975

GLP : no

Test substance : other TS: 4,4'-Methylenedicyclohexyl diisocyanate, purity not below 99.9 %

Remark : The method of determination of the density was described in an earlier

report which is not available (Zhuravleva EZ and Melent’eva TI, All-Union

Scientific and Technical Conference on the Chemistry and Technology of

Production, Processing, and Applications of Polyurethanes and

Intermediates for their Production, February 10-13, 1971, Vladimir.

Abstracts of Papers [in Russian] (1970), p. 17).

Result : The temperature dependence of the density of 4,4'-methylenedicyclohexyl

diisocyanate was determined:

t [°C] density [g/m3]

55 1.0058

60 1.0024

65 0.9990

70 0.9954

75 0.9920

80 0.9884

In the temperature range studied the density of the diisocyanate decreases

linearly with increase of temperature

Reliability : (2) valid with restrictions

Basic data given

19.09.2004 (99)

Type : density

Value : ca. 1.07 g/cm3 at 25 °C

Method : other: DIN EN ISO 2811 

Year :

GLP : no data

Test substance : as prescribed by 1.1 - 1.4

Reliability : (4) not assignable

Manufacturer data without proof

23.11.2004 (32)

Type : density

Value : 1.029 g/cm3 at 70 °C

Method : other: no data 

Year : 1977

GLP : no

Test substance : as prescribed by 1.1 - 1.4

Reliability : (4) not assignable

Manufacturer data without proof

23.11.2004 (6)

Type : density

Value : 1.07 g/cm3 at 20 °C

Method : other: no data 

Year : 2004

GLP : no data

Test substance : other TS: 4,4'-Methylenedicyclohexyl diisocyanate, no purity specified

46
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

2. PHYSICO CHEMICAL DATA ID: 5124-30-1

DATE: 09.11.2006

Remark : No information supplied on the isomeric composition of the substance

Reliability : (4) not assignable

Data from non peer-reviewed handbook or collection of data

19.09.2004 (92)

2.3.1 GRANULOMETRY

2.4 VAPOUR PRESSURE

Value : .0000213 hPa at 25 °C

Decomposition :

Method : Directive 92/69/EEC, A.4 

Year : 1994

GLP : no data

Test substance : as prescribed by 1.1 - 1.4

Result : Vapour pressure at different temperatures:

1.22*10E-05 hPa at 20 °C,

2.13*10E-05 hPa at 25 °C,

3.00*10E-04 hPa at 50 °C

Reliability : (2) valid with restrictions

Non-GLP guideline study

Flag : Critical study for SIDS endpoint

23.11.2004 (16) (32)

Value : .0013 hPa at 25 °C

Decomposition :

Method : other (measured): no data 

Year : 2004

GLP : no data

Test substance : other TS: 4,4'-Methylenedicyclohexyl diisocyanate, no purity specified

Remark : No information supplied on the isomeric composition of the substance

Reliability : (2) valid with restrictions

Data from handbook or collection of data

19.09.2004 (78)

Value : .000436 hPa at 53.7 °C

Decomposition :

Method :

Year : 1975

GLP : no

Test substance : other TS: 4,4'-Methylenedicyclohexyl diisocyanate, purity not below 99.9 %

Method : The vapour pressure was measured by Knudsen's effusion method with the

aid of diaphragms having orifices 4.10E-04 and 17.49E-04 cm2 in area and

Clausing coefficients 0.8060 and 0.8956.

Remark : No information supplied on the isomeric composition of the substance

Result : The temperature dependence of the vapour pressure of

4,4'-methylenedicyclohexyl diisocyanate was determined:

t [°C] vapour pressure [hPa]

53.7 0.000436

75.7 0.002782

85.9 0.006158

99.6 0.016945

47
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

2. PHYSICO CHEMICAL DATA ID: 5124-30-1

DATE: 09.11.2006

110.6 0.037437

114.3 0.046516

130.1 0.128883

Reliability : (2) valid with restrictions

Basic data given

22.11.2004 (99)

Value : .4 hPa at 138 °C

Decomposition :

Method : other (measured): no data 

Year : 1977

GLP : no

Test substance : other TS: 4,4'-Methylenedicyclohexyl diisocyanate, no purity specified

Remark : No information supplied on the isomeric composition of the substance

Result : Vapour pressure at different temperatures:

0.400 hPa at 138 °C; 5.866 hPa at 189 °C

0.533 hPa at 140 °C; 12.66 hPa at 210 °C

0.667 hPa at 145 °C; 29.33 hPa at 232 °C

1.467 hPa at 160 °C; 71.99 hPa at 245 °C

3.333 hPa at 178 °C;

Estimated to be 1013 hPa at 360 °C

Reliability : (4) not assignable

Manufacturer data without proof

19.09.2004 (6)

Value : .0013 hPa at °C

Decomposition :

Method : other (measured): no data 

Year : 2004

GLP : no data

Test substance : other TS:4,4'-Methylenedicyclohexyl diisocyanate, no purity specified

Remark : No information supplied on the isomeric composition of the substance

Reliability : (4) not assignable

Data from non peer-reviewed handbook or collection of data

31.10.2005 (92)

Value : .00058 .00172 hPa at 25 °C

Decomposition :

Method : other (calculated): EPIWIN MPBPWIN v1.41 

Year : 2005

GLP : no

Test substance : other TS: 4,4'-Methylenebis(cyclohexylamine)

Result : Vapor pressure estimations using a boiling point of 320.00 °C (user

entered):

0.000438 mm Hg = 0.00058 hPa (Antoine Method)

0.000671 mm Hg (Modified Grain Method)

0.00129 mm Hg = 0.00172 (Mackay Method)

Selected vapor pressure 0.000671 mm Hg = 0.00089 hPa (Modified Grain

Method)

Reliability : (2) valid with restrictions

Accepted calculation method

Flag : Critical study for SIDS endpoint

22.12.2005 (94)

48
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

2. PHYSICO CHEMICAL DATA ID: 5124-30-1

DATE: 09.11.2006

2.5 PARTITION COEFFICIENT

Partition coefficient : octanol-water

Log pow : at °C

pH value : 

Method : other (calculated): Fragment 

Year : 2004

GLP :

Test substance : other TS: 4,4'-Methylenedicyclohexyl diisocyanate

Method : This endpoint can not be determined experimentally due to rapid

hydrolysis.

Fragment method calculation

 TYPE | NUM | FRAGMENT | COEFF | VALUE 

 Frag | 9 | -CH2- | 0.4911 | 4.4199

 Frag | 4 | -CH | 0.3614 | 1.4456

 Frag | 2 | -N=C=O | 0.0100**| 0.0200

 Const | | | | 0.2290

 log Kow = 6.1145

**An estimated coefficient was used

Remark : The calculation of log Kow for 4,4'-methylenedicyclohexyl diisocyanate is

unsuitable. A calculated theoretical log Kow value reflects the

undissociated molecule without influence of water.

4,4'-Methylenedicyclohexyl diisocyanate hydrolyzes rapidly in the

presence of water with a half life of approximately 2 hours (cf. Chapter

3.1.2, stability in water)

Result : Log Kow (version 1.66 estimate): 6.11

NOTE: Isocyanates hydrolyze....estimate questionable!

In water, 4,4'-methylenedicyclohexyl diisocyanate hydrolyzes with a half-life

of approximately 2 h.

Reliability : (2) valid with restrictions

Accepted calculation method

Flag : Critical study for SIDS endpoint

31.10.2005 (93)

Partition coefficient : octanol-water

Log pow : 2.03 2.55 at °C

pH value : 

Method : other (calculated)

Year : 2003

GLP : no data

Test substance : other TS: 4,4'-Methylenebis(cyclohexylamine)

Result : For 4,4'-methylenebis(cyclohexylamine) a measured log Kow (OECD 107)

of 2.03 and calculated log Kow (QSAR) = 2.55 were determined

Reliability : (2) valid with restrictions

Basic data given

Flag : Critical study for SIDS endpoint

22.12.2005 (58)

Partition coefficient : octanol-water

Log pow : 3.26 at 25 °C

pH value : 

Method : other (calculated): EPIWIN KOWWIN Program (v1.67)

Year : 2005

GLP : no

Test substance : other TS: 4,4'-Methylenebis(cyclohexylamine)

49
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

2. PHYSICO CHEMICAL DATA ID: 5124-30-1

DATE: 09.11.2006

Test condition : LOGKOW Fragment method: 

9 -CH2- [aliphatic carbon] (0.4911) 4.4199

4 -CH [aliphatic carbon] (0.3614) 1.4456

2 -NH2 [aliphatic attach] (-1.4148) -2.8296

Equation constant 0.2290 log Kow = 3.2649

Reliability : (2) valid with restrictions

Accepted calculation method

Flag : Critical study for SIDS endpoint

22.12.2005 (94)

2.6.1 SOLUBILITY IN DIFFERENT MEDIA

Solubility in : Water

Value : at °C

pH value : 

concentration : at °C

Temperature effects :

Examine different pol. :

pKa : at 25 °C

Description :

Stable :

Deg. product :

Method : other: no data

Year : 2004

GLP : no data

Test substance : other TS: 4,4'-Methylenedicyclohexyl diisocyanate, no purity specified

Remark : No information supplied on the isomeric composition of the substance

Result : 4,4'-Methylenedicyclohexyl diisocyanate hydrolyzes in water with a half live

of 2 hours (cf. Chapter 3.1.2 of this IUCLID)

Reliability : (2) valid with restrictions

Data from handbook or collection of data

Flag : Critical study for SIDS endpoint

19.09.2004 (78)

Solubility in : Water

Value : at °C

pH value : 

concentration : at °C

Temperature effects :

Examine different pol. :

pKa : at 25 °C

Description :

Stable :

Deg. product :

Method : other: no data

Year :

GLP : no data

Test substance : as prescribed by 1.1 - 1.4

Result : 4,4'-Methylenedicyclohexyl diisocyanate is insoluble in water. It hydrolyzes

in contact with water and forms carbon dioxide

Reliability : (4) not assignable

Manufacturer data without proof

23.11.2004 (32)

Solubility in : Water

Value : at °C

50
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

2. PHYSICO CHEMICAL DATA ID: 5124-30-1

DATE: 09.11.2006

pH value : 

concentration : at °C

Temperature effects :

Examine different pol. :

pKa : at 25 °C

Description :

Stable :

Deg. product :

Method : other: no data

Year : 2004

GLP : no data

Test substance : other TS: 4,4'-Methylenedicyclohexyl diisocyanate, no purity specified

Remark : No information supplied on the isomeric composition of the substance

Result : 4,4'-Methylenedicyclohexyl diisocyanate is insoluble/reactive in water

Reliability : (4) not assignable

Data from non peer-reviewed handbook or collection of data

31.10.2005 (41) (92)

Solubility in : Water

Value : 5 5.8 g/l at 20 °C

pH value : 11.5 

concentration : 5 g/l at 20 °C

Temperature effects :

Examine different pol. :

pKa : at 25 °C

Description :

Stable :

Deg. product :

Method : other: no data

Year : 2000

GLP : no data

Test substance : other TS: 4,4'-Methylenebis(cyclohexylamine), no purity reported

Result : Data from IUCLID

Source : Data from Bayer AG and Huels AG

Reliability : (2) valid with restrictions

Flag : Critical study for SIDS endpoint

22.12.2005 (58)

Solubility in : Water

Value : 1146 mg/l at 25 °C

pH value : 

concentration : at °C

Temperature effects :

Examine different pol. :

pKa : at 25 °C

Description :

Stable :

Deg. product :

Method : other: calculated: EPIWIN WSKOW v1.41

Year : 2005

GLP : no

Test substance : other TS: 4,4'-Methylenebis(cyclohexylamine)

Remark : 4,4'-Methylenebis(cyclohexylamine) is expected not to hydrolyse in

aquaeous solution due to lack of hydrolyzable groups (expert judgement)

Result : With the WSKOW Program (v1.41), a water solubility of 1146 mg/l is

calculated. 

With the ECOSAR Program (v0.99h), a water solubility of 207.6 mg/l is

51
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

2. PHYSICO CHEMICAL DATA ID: 5124-30-1

DATE: 09.11.2006

calculated. 

With the Water Sol Progam (v1.01), a water solubility of 16055 mg/l is

obtained

Test condition : Equation used to make water solubility estimate:

Log S (mol/l) = 0.693-0.96 log Kow-0.0092(Tm-25)-0.00314 MW +

Correction (Amine, aliphatic 0.838)

log Kow used by water solubility estimate: 3.26

Melting Pt (Tm) = 15.00 °C (Tm = 25 °C used for all liquids)

Reliability : (2) valid with restrictions

Accepted calculation method

22.12.2005 (94)

2.6.2 SURFACE TENSION

2.7 FLASH POINT

Value : 200 °C

Type :

Method : other: DIN 51758 

Year : 1979

GLP : no

Test substance : as prescribed by 1.1 - 1.4

Reliability : (2) valid with restrictions

Basic data given

Flag : Critical study for SIDS endpoint

23.11.2004 (7)

Value : > 201.7 °C

Type :

Method : other: no data 

Year : 2004

GLP : no data

Test substance : other TS: 4,4'-Methylenedicyclohexyl diisocyanate, no purity specified

Remark : No information supplied on the isomeric composition of the substance

Reliability : (2) valid with restrictions

Data from handbook or collection of data

19.09.2004 (78)

Value : 199 °C

Type :

Method : other: no data 

Year : 1976

GLP : no

Test substance : other TS: 4,4'-Methylenedicyclohexyl diisocyanate, purity not below 99.9 %

Remark : The experimental technique and the method used for the calculation were

described in an earlier report which is not available (Monakhov VT,

Methods for Investigating the Fire Hazards of Substances [in Russian], Izd.

"Khimiya", Moscow (1972)).

No information supplied on the isomeric composition of the substance

Result : The experimentally determined flash point of 4,4'-methylenedicyclohexyl

diisocyanate was 199 °C and the calculated flash point was 223 °C. The

results of the determinations were reduced to normal atmospheric pressure

Test condition : The test was performed in an open crucible.

52
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

2. PHYSICO CHEMICAL DATA ID: 5124-30-1

DATE: 09.11.2006

Reliability : (2) valid with restrictions

Basic data given

22.11.2004 (98)

Value : ca. 200 °C

Type :

Method : other: DIN EN 22719 

Year :

GLP : no data

Test substance : as prescribed by 1.1 - 1.4

Reliability : (4) not assignable

Manufacturer data without proof

23.11.2004 (32)

Value : 210 °C

Type :

Method : other: no data 

Year : 1977

GLP : no

Test substance : as prescribed by 1.1 - 1.4

Reliability : (4) not assignable

Manufacturer data without proof

23.11.2004 (6)

Value : 201.7 °C

Type :

Method : other: no data 

Year : 2004

GLP : no data

Test substance : other TS: 4,4'-Methylenedicyclohexyl diisocyanate, no purity specified

Remark : No information supplied on the isomeric composition of the substance

Reliability : (4) not assignable

Data from non peer-reviewed handbook or collection of data

22.12.2005 (41)

Value : > 110 °C

Type :

Method : other: no data 

Year : 2004

GLP : no data

Test substance : other TS: 4,4'-Methylenedicyclohexyl diisocyanate, no purity specified

Remark : No information supplied on the isomeric composition of the substance

Reliability : (4) not assignable

Data from non peer-reviewed handbook or collection of data

22.12.2005 (92)

2.8 AUTO FLAMMABILITY

Value : 225 °C at 

Method : other: no data 

Year : 1976

GLP : no

Test substance : other TS: 4,4'-Methylenedicyclohexyl diisocyanate, purity not below 99.9 %

53
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

2. PHYSICO CHEMICAL DATA ID: 5124-30-1

DATE: 09.11.2006

Remark : The experimental technique and the method used for the calculation were

described in an earlier report which is not available (Monakhov VT,

Methods for Investigating the Fire Hazards of Substances [in Russian], Izd.

"Khimiya", Moscow (1972)).

No information supplied on the isomeric composition of the substance

Result : The experimentally determined ignition point of 4,4'-methylenedicyclohexyl

diisocyanate was 225 °C and the calculated ignition point was 226 °C. The

results of the determinations were reduced to normal atmospheric

pressure.

Test condition : The test was performed in an open crucible

Reliability : (2) valid with restrictions

Basic data given

Flag : Critical study for SIDS endpoint

22.11.2004 (39) (98)

2.9 FLAMMABILITY

2.10 EXPLOSIVE PROPERTIES

2.11 OXIDIZING PROPERTIES

2.12 DISSOCIATION CONSTANT

2.13 VISCOSITY

Value : ca. 30 - mPa s (dynamic) at 25 °C

Result :

Method : other: DIN ISO EN 3219/A.3

Year :

GLP : no data

Test substance : as prescribed by 1.1 - 1.4

Reliability : (4) not assignable

Manufacturer data without proof

Flag : Critical study for SIDS endpoint

23.11.2004 (32)

Value : 12.658 - mPa s (dynamic) at 55 °C

Result :

Method : other: no data

Year : 1975

GLP : no

Test substance : other TS: 4,4'-Methylenedicyclohexyl diisocyanate, purity not below 99.9 %

Remark : The method of determination of the viscosity was described in an earlier

report which is not available (Zhuravleva EZ and Melent’eva TI, All-Union

Scientific and Technical Conference on the Chemistry and Technology of

Production, Processing, and Applications of Polyurethanes and

Intermediates for their Production, February 10-13, 1971, Vladimir.

Abstracts of Papers [in Russian] (1970), p. 17).

No information supplied on the isomeric composition of the substance

Result : The temperature dependence of the viscosity of 4,4'-methylenedicyclohexyl

54
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

2. PHYSICO CHEMICAL DATA ID: 5124-30-1

DATE: 09.11.2006

diisocyanate was determined:

t [°C] viscosity [mPaxs]

55 12.658 

60 10.452

65 8.674

70 7.220 

75 6.005 

80 4.890

Reliability : (2) valid with restrictions

Basic data given

19.09.2004 (99)

Value : 6.3 - mm2/s (static) at 70 °C

Result :

Method : other: measured not specified

Year : 1977

GLP : no

Test substance : other TS: 4,4'-Methylenedicyclohexyl diisocyanate, no purity specified

Result : At 70 °C: 6.3 mm2/s

At 80 °C: 5.1 mm2/s 

At 90 °C: 4.1 mm2/s

Reliability : (4) not assignable

Manufacturer data without proof

19.09.2004 (6)

2.14 ADDITIONAL REMARKS

55
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

3. ENVIRONMENTAL FATE AND PATHWAYS ID: 5124-30-1

DATE: 09.11.2006

3.1.1 PHOTODEGRADATION

Type : air

Light source :

Light spectrum : nm

Relative intensity : based on intensity of sunlight

Conc. of substance : at 25 °C

INDIRECT PHOTOLYSIS

Sensitizer : OH

Conc. of sensitizer : 500000 molecule/cm3

Rate constant : .000000000026 cm3/(molecule*sec)

Degradation : 50 % after 15 hour(s)

Deg. product :

Method : other (calculated): EPIWIN AOPWIN v1.91, 2000 

Year : 2004

GLP :

Test substance : other TS: 4,4'-Methylenedicyclohexyl diisocyanate

Remark : The EPIWIN AOPWIN v1.91 program does not take into account that

4,4'-methylenedicyclohexyl diisocyanate is sensitive to hydrolysis e.g. in

aerosols with aquatic phases

Result : A half-life of about 15.0 h based on a 24-hour day is estimated due to

reaction with photochemically produced hydroxyl radicals (OH

concentration: 0.5E+6 radicals/cm3)

Reliability : (2) valid with restrictions

Accepted calculation method

Flag : Critical study for SIDS endpoint

04.11.2005 (28)

3.1.2 STABILITY IN WATER

Type : abiotic

t1/2 pH4 : at °C

t1/2 pH7 : at °C

t1/2 pH9 : at °C

Deg. product :

Method : other: Decrease of NCO-Content in Water, followed by GC-analysis

Year : 1999

GLP : yes

Test substance : as prescribed by 1.1 - 1.4

Method : 1 g of the test substance was dissolved in acetonitrile and filled up to 100

ml. 10 ml of this solution were pipetted, 40 ml of acetonitrile added (see

remark) and filled up with water to 100 ml. This solution was injected into

the gas chromatography system every 20 min.

Remark : The preparations with a lower content of acetonitrile were cloudy due to the

low water solubility of the test substance. The determination of the

concentration change in such an inhomogenous solution gives wrong

results. For this reason the lowest concentration of acetonitrile required to

obtain a clear solution was chosen. The solution of the test substance in

acetonitrile was stable over measurement time.

Result : The half-time of the test substance in water was determined to be

approximately 2 hours at 23 °C (t1/2 = 1.97 hours). The rate constant kobs

was 9.78E-05 1/s.

Test condition : The content of test substance was determined by means of capillary gas

chromatography and flame ionisation detection (GC-FID) under the

56
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

3. ENVIRONMENTAL FATE AND PATHWAYS ID: 5124-30-1

DATE: 09.11.2006

following conditions: 

Chromatographic column: fused silica capillary, length: 30

m, internal diameter: 0.32 mm, film thickness: 0.25 μm;

Stationary phase: HP 1; Carrier gas: helium;

Split: 30 ml/min; Pressure: 0.6 bar;

Temperature programm:

 Temp [°C] Time [min] Ramp [K/min]

 180 0 10 

 260 1 -

Detector temperature: 250 °C;

Sample injection: split injection;

Injection volume: 2 μl;

Quantification was performed by area comparison

Reliability : (2) valid with restrictions

Study meets generally accepted scientific principles

Flag : Critical study for SIDS endpoint

23.11.2004 (20)

Type : abiotic

t1/2 pH4 : at °C

t1/2 pH7 : at °C

t1/2 pH9 : at °C

Degradation : 100 % after 5 day(s) at pH and °C

Deg. product : yes

Method : OECD Guide-line 111 "Hydrolysis as a Function of pH"

Year : 2004

GLP : yes

Test substance : other TS: 4,4'-Methylenedicyclohexyl diisocyanate, > 99.5 % purity

Deg. products : 1761-71-3 217-168-8 4,4'-methylenebis(cyclohexylamine)

Remark : The aim of this study was to determine the degradation products formed

when 4,4'-methylenedicyclohexyl diisocyanate reacts with water.

Result : - The aqueous phase contained 3 isomers of 4,4 ́-methylenedicyclohexyl

diisocyanate; they were identified by GC and HPLC (CAS 1761-71-3).

- Additionally, HPLC showed traces of a trimeric diamine. The monomers

were connected by urea-groups. 

- The insoluble droplets adhered to the glass wall were analysed with IRSpectroscopy. They contained urea components (polyurea) as well as

traces of isocyanate-groups. The polymeric urea compounds encapsulated

isocyanate groups which slows down the complete hydrolysis of the

isocyanate groups.

Test condition : - Preliminary test only performed in demineralized water

- 2.64 g of the test substance were dissolved in 10 ml acetonitrile. 1 ml of

this solution was diluted to 100 ml with demineralized water. The final

solution was thus 0.01 mol/l (2.64 g/l). Incubation was at 50 °C during 5

days under continuous stirring.

- Water was not buffered for the preliminary test.

- The solution was extracted with methylene chloride after adjusting the

solution at pH 11 and then analysed with GC-MS, HPLC-MS and IRspectroscopy.

Reliability : (2) valid with restrictions

Guideline study with acceptable restrictions

Flag : Critical study for SIDS endpoint

04.11.2005 (29)

3.1.3 STABILITY IN SOIL

57
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

3. ENVIRONMENTAL FATE AND PATHWAYS ID: 5124-30-1

DATE: 09.11.2006

3.2.1 MONITORING DATA

Type of measurement : concentration at contaminated site

Media : air

Concentration : 

Method : LC/UV

Method : The thermal degradation products of polyurethanes (PURs) and exposure

to isocyanates were studied by stationary and personal measurements in 5

different occupational environments (car repair shop, machining of PUR

coating, injection moulding, welding of district heating pipes, and

installation of PUR floor covering) from September 1999 until November

2000

Remark : During grinding and welding thermal degradation products of certain

polyurethanes were reported to include 4,4'-methylenedicyclohexyl

diisocyanate. In the air samples taken during joint welding of PUR floor

covering and samples taken in the breathing zone of a floor covering layer

who was welding floor covering on his knees in a small room with no

ventilation small amounts of 4,4'-methylenedicyclohexyl diisocyanate were

detectable (limit of detection <0.6 mg/m3).

Result : Traces of 4,4'-methylenedicyclohexyl diisocyanate (up to 2 μg/m3) were

detected as a thermolytic degradation product during joint welding of

polyurethane floor covering in a small room without ventilation in a car

repair shop

Test condition : - Isocyanates were collected on glass fiber filters impregnated with 1-(2-

methoxyphenyl)piperazine (2MP) and via the n-dibutylamine impinger

method 

- Derivatives analyzed by LC with UV (250 nm) and electrochemical

detection

- Limit of quantification < 0.02-0.1 μg per sample depending on isocyanate

(not indicated which is valid for 4,4 ́-methylenedicyclohexyl diisocyanate)

Test substance : 4,4'-Methylenedicyclohexyl diisocyanate, purity 100 %, from Tokyo Kasei

Organic Chemicals, Tokyo, used as external standard for quantification

Reliability : (2) valid with restrictions

Basic data given

Flag : Critical study for SIDS endpoint

22.11.2004 (62)

Type of measurement : concentration at contaminated site

Media : air

Concentration : < .0022 μg/l

Method : HPLC

Result : 4,4'-Methylenedicyclohexyl diisocyanate was not detectable

Test condition : - US plant manufacturing water pipes with equipment to measure flow rate

- Asbestos type insulation coated the inside of a significant part of the plant

buildings

- Several chemicals were handled in the plant, e.g.

4,4'-methylenedicyclohexyl diisocyanate, haloorganics, and epichlorohydrin

- 3 samples taken in September and October, 1979

- Isocyanate absorbed in nitro reagent in impinger, air flow rate 1 l/min

- Analysis by NIOSH method N420 (modified), via HPLC, 

- Limit of detection: 0.0006 mg/sample (<0.0022 μg/l)

Reliability : (2) valid with restrictions

Basic data given

Flag : Critical study for SIDS endpoint

26.11.2004 (71)

Type of measurement : concentration at contaminated site

58
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

3. ENVIRONMENTAL FATE AND PATHWAYS ID: 5124-30-1

DATE: 09.11.2006

Media : air

Concentration : < .02 .03 μg/l

Method : GC

Remark : Author states that it is not clear whether the measurements are valid

because reactions of 4,4'-methylenedicyclohexyl diisocyanate may have

occured in the sampling solution before measurements

No sensitizing effects of 4,4'-methylenedicyclohexyl diisocyanate were

found in approximately 200 workers of this US manufacturing plant

Result : 4,4'-Methylenedicyclohexyl diisocyanate was not detectable

Test condition : - US plant manufacturing data processing and control equipment was

monitored

- Several chemicals were handled in the plant, e.g.

4,4'-methylenedicyclohexyl diisocyanate, haloorganics, cyanide, and nitric

acid

- 5 samples taken on May 7, 1975 (NIOSH survey)

- Air sampling volume of 294-475 l/sample

- Isocyanate absorbed in unspecified solution

- GC

- Limit of detection: 0.01 mg/sample (equals to a limit of detection of 0.02-

0.03 mg/m3)

Reliability : (4) not assignable

Documentation insufficient for assesment

22.11.2004 (82)

3.2.2 FIELD STUDIES

3.3.1 TRANSPORT BETWEEN ENVIRONMENTAL COMPARTMENTS

Type : adsorption

Media : water - soil

Air : % (Fugacity Model Level I)

Water : % (Fugacity Model Level I)

Soil : % (Fugacity Model Level I)

Biota : % (Fugacity Model Level II/III)

Soil : % (Fugacity Model Level II/III)

Method : other: calculated with PCKOCWIN v1.66, 2000

Year : 2004

Remark : Calculation is not suitable due to hydrolysis. In water,

4,4'-methylenedicyclohexyl diisocyanate hydrolyzes with a half-life of

approximately 2 h

Result : Koc = 3.762E+05

log Koc = 5.575

Test substance : 4,4'-Methylenedicyclohexyl diisocyanate

Reliability : (2) valid with restrictions

Accepted calculation method

Flag : Critical study for SIDS endpoint

03.11.2005 (28)

Type : adsorption

Media : water - soil

Air : % (Fugacity Model Level I)

Water : % (Fugacity Model Level I)

Soil : % (Fugacity Model Level I)

Biota : % (Fugacity Model Level II/III)

Soil : % (Fugacity Model Level II/III)

59
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

3. ENVIRONMENTAL FATE AND PATHWAYS ID: 5124-30-1

DATE: 09.11.2006

Method : other: calculated with PCKOCWIN v1.66, 2000

Year : 2005

Result : Koc (estimated): 672

Test substance : 4,4'-Methylenebis(cyclohexylamine)

Reliability : (2) valid with restrictions

Accepted calculation method

Flag : Critical study for SIDS endpoint

31.10.2005 (94)

3.3.2 DISTRIBUTION

Media : water - air

Method : other (calculation): EPIWIN HENRY (v3.10) Program

Year : 2005

Result : HENRYs LAW CONSTANT at 25 °C:

- Bond estimate: 4.54E-009 atm-m3/mole = 1.86E-007 unitless = 0.00046

Pa-m3/mole

Bond estimation:

22 Hydrogen to carbon (aliphatic) bonds -2.6329

4 Hydrogen to nitrogen bonds 5.1341

14 C-C fragments 1.6283

2 C-N fragments 2.6020

Total 6.731

- Group estimation: Incomplete

- Estimation from vapor pressure/water solubility equation using a vapor

pressure of 0.000671 mm Hg and a water solubility of 1146 mg/l: 1.621E007 atm-m3/mole = 0.016 Pa-m3/mole

Test substance : 4,4'-Methylenebis(cyclohexylamine)

Reliability : (2) valid with restrictions

Accepted calculation method

Flag : Critical study for SIDS endpoint

03.11.2005 (94)

Media : air - biota - sediment(s) - soil - water

Method : Calculation according Mackay, Level I

Year : 2000

Result : Distribution on compartments:

Air: 0.041 %

Soil: 0.880 %

Water: 98.256 %

Sediment: 0.823 %

Biota: 0.001 %

Source : Huels AG, Marl (calculation in IUCLID)

Test condition : Input parameters:

Molar mass: 210.36 g/mol

log Kow: 2.03

Vapour pressure: 0.033 Pa

Water solubility: 5.8 g/l at 20 °C

-----------------------------------

Equations used for additional data:

log Koc = 0.989 log Kow - 0.346

-----------------------------------

Volumes used (m3):

Air: 6 000 000 000

Soil: 45 000

60
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

3. ENVIRONMENTAL FATE AND PATHWAYS ID: 5124-30-1

DATE: 09.11.2006

Water: 7 000 000

Sediment: 21 000

Suspended Sediment: 35

Biota: 7

Test substance : 4,4'-Methylenebis(cyclohexylamine)

Reliability : (2) valid with restrictions

Accepted calculation method

Flag : Critical study for SIDS endpoint

22.12.2005 (58)

Media : air - biota - sediment(s) - soil - water

Method : Calculation according Mackay, Level I

Year : 2005

Remark : Result is different from the result of the EU PBT Working Group because

different (mostly calculated) input parameters were used

Result : Compartment

Water 37.70 %

Air 0.155 %

Sediment 1.350 %

Soil 60.75 %

Suspended sediment 0.042 %

Aerosol <0.001 %

Aquatic biota 0.0033 %

Test condition : Input parameters:

Temperature 25 °C

Vapour pressure 0.089 Pa

Water solubility 1146 mg/l 

log Kow3.26

Melting point 320 °C

Test substance : 4,4'-Methylenebis(cyclohexylamine)

Reliability : (2) valid with restrictions

Accepted calculation method

04.11.2005 (30)

3.4 MODE OF DEGRADATION IN ACTUAL USE

3.5 BIODEGRADATION

Type : aerobic

Inoculum : activated sludge, domestic, non-adapted

Concentration : 100 mg/l related to Test substance

related to 

Contact time :

Degradation : 0 (±) % after 28 day(s)

Result : other: not readily biodegradable

Control substance : Benzoic acid, sodium salt

Kinetic : 14 day(s) 87 %

 %

Deg. product :

Method : Directive 92/69/EEC, C.4-D 

Year : 2000

GLP : yes

Test substance : as prescribed by 1.1 - 1.4

Remark : The used concentration of the test substance did not show toxic effects to

bacteria (toxicity control)

61
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

3. ENVIRONMENTAL FATE AND PATHWAYS ID: 5124-30-1

DATE: 09.11.2006

Test condition : - Activated sludge concentration in test flasks: 30 mg ss/l.

- Test temperature: 20 +/- 1 °C.

Reliability : (1) valid without restriction

GLP guideline study

Flag : Critical study for SIDS endpoint

23.11.2004 (21)

Type : aerobic

Inoculum : activated sludge, domestic

Concentration : 12 mg/l related to Test substance

related to 

Contact time :

Degradation : 0 (±) % after 28 day(s)

Result : other: not readily biodegradable

Control substance : Aniline

Kinetic : 28 day(s) 83 %

 %

Deg. product :

Method : OECD Guide-line 301 F "Ready Biodegradability: Manometric

Respirometry Test"

Year : 1992

GLP : yes

Test substance : as prescribed by 1.1 - 1.4

Remark : In a first respirometer test performed with a test substance concentration of

100 mg/l, the test substance showed toxic effects to bacteria. Thereupon a

Closed Bottle Test should be conducted with lower test substance

concentrations. But at last this test was not feasible because neither a

stock solution could be prepared nor a direct weighing of test substance

was possible. Therefore the respirometer test was performed with a test

substance concentration of 12 mg/l.

Test condition : - Activated sludge was taken from laboratory wastewater treatment system,

sludge concentration: 30 mg dry weight/l

- Test temperature 20 +/- 1 °C

Reliability : (2) valid with restrictions

Guideline study with acceptable restrictions (concentration tested was

lower than the required by the OECD TG 301 of 100 mg/l, as the toxicity

threshold towards bacteria available at the time was lower than the current

available peer-reviewed toxicity)

Flag : Critical study for SIDS endpoint

23.11.2004 (14)

Type : aerobic

Inoculum :

Contact time :

Degradation : (±) % after 

Result : other: 4 out of 6 estimation methods predict fast biodegradation, with an

ultimate biodegradation timeframe of weeks

Deg. product :

Method : other: (calculated) EPIWIN BIOWIN program 

Year : 2005

GLP : no

Test substance : other TS: 4,4'-Methylenebis(cyclohexylamine)

Remark : Although EPIWIN is an accepted calculation method for many physical

parameters, its reliability for estimation of biodegradation is not clearly

proofed

Result : Biowin1 (Linear Model Prediction): Biodegrades fast

Biowin2 (Non-Linear Model Prediction): Biodegrades fast

Biowin3 (Ultimate Biodegradation Timeframe): Weeks

62
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

3. ENVIRONMENTAL FATE AND PATHWAYS ID: 5124-30-1

DATE: 09.11.2006

Biowin4 (Primary Biodegradation Timeframe): Days-Weeks

Biowin5 (MITI Linear Model Prediction): Does not biodegrade fast

Biowin6 (MITI Non-Linear Model Prediction): Does not biodegrade fast

Reliability : (4) not assignable

Documentation insufficient for assesment

Flag : Critical study for SIDS endpoint

22.12.2005 (94)

Type : aerobic

Inoculum :

Contact time :

Degradation : 20 (±) % after 28 day(s)

Result : other: 4,4'-Methylenebis(cyclohexylamine) is at least inherently

biodegradable

Deg. product :

Method : other: Zahn-Wellens

Year : 2000

GLP : no data

Test substance : other TS: 4,4'-Methylenebis(cyclohexylamine)

Remark : Only short documentation available

Result : Biodegradation tests on 4,4'-methylenebis(cyclohexylamine) show that the

substance is at least inherently biodegradable

Reliability : (2) valid with restrictions

Reliable source

Flag : Critical study for SIDS endpoint

02.01.2006 (58)

3.6 BOD5, COD OR BOD5/COD RATIO

01.04.2004

3.7 BIOACCUMULATION

Elimination :

Method :

Year : 2003

GLP :

Test substance : other TS: 4,4'-Methylenedicyclohexyl diisocyanate

Remark : 4,4'-Methylenedicyclohexyl diisocyanate hydrolyzes rapidly in the presence

of water with a half life of approximately 2 hours. Therefore a risk

estimation regarding the bioaccumulation potential of

4,4'methylenedicyclohexyl diisocyanate on the basis of a log Kow,

determined by QSAR, is misleading. A calculated theoretical log Kow value

reflects the undissociated molecule without influence of water.

According to the EU Technical Guidance Document a substance is

regarded as potentially bioaccumulative if the log Kow exceeds 3 and the

half life time in water exceeds 12 hours. This is not the case for

4,4'methylenedicyclohexyl diisocyanate. The substance is not persistent in

water due to the rapid hydrolysis. Therefore it is not bio-available. Possible

hydrolyzation products are less lipophilous. On the basis of these

information it can not be expected that bioaccumulation of

4,4'methylenedicyclohexyl diisocyanate occurs

Reliability : (2) valid with restrictions

63
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

3. ENVIRONMENTAL FATE AND PATHWAYS ID: 5124-30-1

DATE: 09.11.2006

Accepted calculation method

Flag : Critical study for SIDS endpoint

04.11.2005 (27)

Species :

Exposure period : at 25 °C

Concentration :

BCF : 7 18

Elimination :

Method : other: (calculated) BCF-equation from EPIWIN BCF Program (v2.15) 

Year : 2005

GLP : no

Test substance : other TS: 4,4'-Methylenebis(cyclohexylamine)

Result : Equation used to make BCF estimate:

log BCF = 0.77 log Kow - 0.70

log Kow used by BCF estimates: 

measured log Kow (OECD 107) of 2.03

log BCF values of 0.863 (BCF = 7)

calculated log Kow (CLOGP3 program) = 2.55

Estimated log BCF = 1.264 (BCF = 18).

Conclusion: Not bioaccumulative according to EU TGD

Reliability : (2) valid with restrictions

Accepted calculation method

Flag : Critical study for SIDS endpoint

22.12.2005 (58)

Species :

Exposure period : at 25 °C

Concentration :

BCF : 65 

Elimination :

Method : other: (calculated) EPIWIN BCF Program (v2.15)

Year : 2005

GLP : no

Test substance : other TS: 4,4'-Methylenebis(cyclohexylamine)

Result : Equation used to make BCF estimate:

log BCF = 0.77 log Kow - 0.70

log Kow used by BCF estimates: 3.26

Estimated log BCF = 1.814 (BCF = 65.16).

Conclusion: Not bioaccumulative according to EU TGD

Reliability : (2) valid with restrictions

Accepted calculation method

Flag : Critical study for SIDS endpoint

22.12.2005 (94)

3.8 ADDITIONAL REMARKS

64
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

4. ECOTOXICITY ID: 5124-30-1

DATE: 09.11.2006

4.1 ACUTE/PROLONGED TOXICITY TO FISH

Type : static

Species : Brachydanio rerio (Fish, fresh water)

Exposure period : 96 hour(s)

Unit : mg/l

LC0 : >= 8.1 

Limit test : yes

Analytical monitoring : yes

Method : Directive 92/69/EEC, C.1 

Year : 2000

GLP : yes

Test substance : other TS: Desmodur W, purity: 99.5 % (21.1 % trans,trans4,4'-methylenedicyclohexyl diisocyanate, 50.2 % trans,cis4,4'-methylenedicyclohexyl diisocyanate, and 28.2 % cis,cis4,4'-methylenedicyclohexyl diisocyanate

Remark : Before beginning of the study a pretreatment was performed with the test

substance according to the recommendation mentioned in the OECD

Guidance Document on aquatic toxicity testing of difficult substances and

mixtures in order to accelerate the solution procedure. For that purpose a

five fold amount (30 mg/l) of the maximum water solubility of the test

substance in the preliminary test (6 mg/l) was weighed into water, treated

for 60 seconds at 8000 rpm with an ultra-turrax, afterwards stirred for 24

hours on a magnetic stirrer and finally filtered.

Analysis of the only test substance concentration and the control was

performed daily by means of TOC determination.

The test result LC0 >= 8.1 mg/l (10 % mortality rate) refers to a

concentration of the test substance which was calculated directly from

analytically determined TOC values (arithmetic mean). According to

relevant product information, 1 mg/l TOC equals to 1.5 mg/l of the test

substance (structural formula C15H22N2O2, molecular weight 262.4

g/mol).

Deviating from the preliminary test, a mortality rate of 10 % was detected in

the main test at the limit tested concentration of 6 mg/l. The validity criteria

of the test guideline permit a maximum mortality of 10 % in the control.

Result : LC0 >= 8.1 mg/l (10% mortality rate)

Test condition : - The test was conducted in a ventilated vessel (300 x 135 x 200 mm) filled

with 5 l test medium.

- Synthetic fresh water (in accordance with ISO) was used for dilution. The

water hardness was 14.1 °dH. 

- 20 fishes were used for the test (10 fishes for the test vessel and 10 for

the control). Length: 2.9-3.5 cm. Fresh weight of 10 fishes: 4.41 g (control)

and 4.02 g (test vessel).

- The test was performed at the nominal limit test concentration of 6 mg/l.

- Photoperiod: 16 hours light/8 hours dark.

- Test temperature in the test vessel during the study period was 21.3 to

21.8 °C, pH-value was 7.8 to 8.0 and oxygen concentration varied between

8.1 and 8.6 mg/l (oxygen saturation: 93.8 to 99.5%).

Reliability : (1) valid without restriction

GLP guideline study

Flag : Critical study for SIDS endpoint

04.11.2005 (22)

Type : static

Species : Brachydanio rerio (Fish, fresh water)

Exposure period : 96 hour(s)

65
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

4. ECOTOXICITY ID: 5124-30-1

DATE: 09.11.2006

Unit : mg/l

LC0 : .69 

LC50 : 1.2 

LC100 : 2.76 

Limit test : no

Analytical monitoring : no

Method :

Year : 1992

GLP : yes

Test substance : other TS: Desmodur W, purity: 91.6 % (24.38 % trans,trans4,4'-methylenedicyclohexyl diisocyanate, 43.00 % trans,cis4,4'-methylenedicyclohexyl diisocyanate, and 24.20 % cis,cis4,4'-methylenedicyclohexyl diisocyanate

Method : German UBA-Proposal "Letale Wirkung beim Zebrabaerbling Brachydanio

rerio" (LC 0, LC 50, LC 100; 48-96 Stunden), May 1984 (this proposal is in

most parts equivalent to OECD TG 203).

Remark : Because of the high reactivity of the test substance in water and the low

water solubilty, respectively, no determination of the test substance

concentrations in the test vessels was performed during the test.

This test has not been taken into account for the assessment of

4,4'-methylenedicyclohexyl diisocyanate. 4,4'-Methylenedicyclohexyl

diisocyanate is not a consumer product and may only be released into the

aquatic environment from manufacturing or processing. The aquatic halflife of this isocyanate is approximately 2 hours. Possible aquatic emissions

would enter a wastewater treatment plant with a hydraulic retention time of

several hydrolysis half-lives, which means that virtually all isocyanate

would hydrolyze to the corresponding amine during wastewater treatment

before it enters environmental waters. The hydrolysis product,

4,4'-methylenebis(cyclohexylamine), is virtually the only form of the test

substance in the aquatic environment. Thus, for assessment, not the

isocyanate, but its hydrolysis product has to be tested.

In the test at issue, the test substance was used immediately after contact

with water, and significant concentrations of the unhydrolyzed isocyanate

were present at the start of incubation. Thus, these test conditions do not

reflect environmental conditions, and were not used for assessment

Test condition : - The test was conducted in ventilated vessels (300 x 135 x 200 mm) each

filled with 5 l test medium.

- Synthetic fresh water (in accordance with ISO) was used for dilution. The

water hardness was 12.8 °dH. 

- 80 fishes were used for the test (10 fishes for each of the seven test

vessels and 10 for the control). Length: 2.5-3.5 cm. Fresh weight of 10

fishes: 2.16 g (control) and 2.17 to 3.50 g (test vessels).

- To prepare the stock solution an amount of the test substance was

weighed into water and treated with an ultra-turrax for 60 seconds at 8000

rpm.

- The following nominal concentrations were tested: 0.08, 0.17, 0.35, 0.69,

1.38, 2.76 and 5.53 mg/l.

- Test temperature in the test vessels during the study period was between

20.7 and 21.6 °C, pH-value was between 7.5 and 8.1, and oxygen

concentration varied between 8.3 and 9.4 mg/l (oxygen saturation: 96.0 to

108.0%)

Reliability : (2) valid with restrictions

Comparable to guideline study with acceptable restrictions

22.12.2005 (14)

4.2 ACUTE TOXICITY TO AQUATIC INVERTEBRATES

66
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

4. ECOTOXICITY ID: 5124-30-1

DATE: 09.11.2006

Type : static

Species : Daphnia magna (Crustacea)

Exposure period : 48 hour(s)

Unit : mg/l

EC0 : >= 8.3 

Limit Test : yes

Analytical monitoring : yes

Method : Directive 92/69/EEC, C.2 

Year : 2000

GLP : yes

Test substance : other TS: Desmodur W, purity: 99.5 % (21.1 % trans,trans4,4'-methylenedicyclohexyl diisocyanate, 50.2 % trans,cis4,4'-methylenedicyclohexyl diisocyanate, and 28.2 % cis,cis4,4'-methylenedicyclohexyl diisocyanate

Remark : Before beginning of the study a pretreatment was performed with the test

substance according to the recommendation mentioned in the OECD

Guidance Document on aquatic toxicity testing of difficult substances and

mixtures in order to accelerate the solution procedure. For that purpose a

five fold amount (45 mg/l) of the maximum water solubility of the test

substance in the preliminary test (9 mg/l) was weighed into water, treated

for 60 seconds at 8000 rpm with an ultra-turrax, afterwards stirred for 24

hours on a magnetic stirrer and finally filtered.

Analysis of the only test substance concentration and the control was

performed at the start of the test and after 48 hours of exposure by means

of TOC determination.

The test result EC0 >= 8.3 mg/l refers to a concentration of the test

substance which was calculated directly from analytically determined TOC

values (arithmetic mean).

According to relevant product information, 1 mg/l TOC equals to 1.5 mg/l of

the test substance (structural formula C15H22N2O2, molecular weight

262.4 g/mol).

Test condition : - The test was conducted in a not ventilated cylindrical test vessel

(diameter: 4.0 cm, height: 6.5 cm) filled with 20 ml test medium.

- M4-Medium according to Elendt and BGA (1992) was used for dilution.

The water hardness was 14.2 °dH. 

- 20 daphnids, 0-24 hours old, were used for the test (10 daphnids for the

test vessel and 10 for the control).

- The test was performed at the nominal limit test concentration of 9 mg/l.

- Photoperiod: 16 hours light/8 hours dark.

- Test temperature in the test vessel after 48 hours was 20.2 °C, pH-value

was 7.9 and oxygen concentration was 8.5 mg/l.

Reliability : (1) valid without restriction

GLP guideline study

Flag : Critical study for SIDS endpoint

04.11.2005 (23)

4.3 TOXICITY TO AQUATIC PLANTS E.G. ALGAE

Species : Scenedesmus subspicatus (Algae)

Endpoint : growth rate

Exposure period : 72 hour(s)

Unit : mg/l

EC50 : > 5 

Limit test : no

Analytical monitoring : yes

Method : Directive 92/69/EEC, C.3 

Year : 2000

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OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

4. ECOTOXICITY ID: 5124-30-1

DATE: 09.11.2006

GLP : yes

Test substance : other TS: Desmodur W, purity: 99.5 % (21.1 % trans,trans4,4'-methylenedicyclohexyl diisocyanate, 50.2 % trans,cis4,4'-methylenedicyclohexyl diisocyanate, and 28.2 % cis,cis4,4'-methylenedicyclohexyl diisocyanate

Remark : Results of analytical monitoring (test substance concentration):

- Control at start of incubation < 2 mg/l, after 72 h 4 mg/l

- Incubation solution (nominal 5 mg/l) at start of incubation 4 mg/l, after 72

h 6 mg/l

- Incubation solution without algae (nominal 5 mg/l) at start of incubation 4

mg/l, after 72 h 3 mg/l

As the test concentrations for the determination of the NOEC and LOEC

were below the detection limit of the TOC determination (2 mg/l) the test

results refer to nominal concentrations. The arithmetic means of the TOC

determination of the highest test concentration (5 mg/l) exhibited an

expected recovery rate of the test substance based on organic C (4.5 mg/l

= 90 % recovery)

Result : Cell number/ml (x10E3)

 24h 48h 72h

Control: 41.1 140 304

0.08: 48.9 157 307

0.16: 50.0 158 450

0.31: 46.7 166 361

0.63: 36.7 142 197

1.3: 27.8 143 165

2.5: 22.2 153 211

5.0: 22.2 150 180

Growth and growth rates at several concentrations:

Control: 0 and 0

0.08: -8.4* and 0

0.16: -32.5* and -18.*

0.31: -19.5* and -9.1*

0.63: 18.2 and 9.1

1.3: 26.0 and 18.2

2.5: 16.9 and 9.1

5: 23.1 and 9.1

*increase

Toxicities:

Endpoint growth: EbC50 > 5 mg/l,

Endpoint growth rate: ErC50 > 5 mg/l,

NOEC (cell density after 72 h): 0.31 mg/l,

LOEC (cell density after 72 h): 0.63 mg/l

Test condition : - Preparation of stock solution according to the recommendation mentioned

in the OECD Guidance Document on aquatic toxicity testing of difficult

substances and mixtures: A 5 fold concentration of (37.5 mg/l) of the

maximum water solubility of the test substance in preliminary test (7.5 mg/l)

was weighed into water and treated for 60 seconds at 8000 rpm in an ultra

turrax. The suspesion was stirred by a magnetic stirrer for 24 h.

Undissolved particles were removed by filtration through a folded filter of

the pore size of 7-12 μm

- The cultivation of stock cultures, precultures and test cultures was

performed in a light chamber at 23 +/- 2 °C and with a quantum flux which

equals 120 μE/m2 x s

- The test was conducted in Erlenmeyer flasks (300 ml) with stoppers, each

filled with 100 ml of test medium. The test flasks were put in a light

chamber with shaker

- Deionised water was used for dilution

- Inoculum: algal suspension taken from an exponentially growing

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4. ECOTOXICITY ID: 5124-30-1

DATE: 09.11.2006

preculture which serves to adjust an initial cell density of 10,000 cells per

ml

- The following nominal concentrations were tested: 0.08, 0.16, 0.31, 0.63,

1.3, 2.5 and 5 mg/l

- The pH-value in the test vessels was 8.1 at the beginning of the test and

between 9.3 and 10.4 after 72 hours of exposure

- Analytical monitoring by TOC measurement (limit of detection 2 mg C/l).

Analysis of the highest test concentration and the control was performed at

the start of the test and after 72 h of exposure. Additionally analysis of the

highest concentration without algal inoculum was performed at the same

time intervals

Reliability : (1) valid without restriction

GLP guideline study

Flag : Critical study for SIDS endpoint

18.01.2006 (24)

4.4 TOXICITY TO MICROORGANISMS E.G. BACTERIA

Type : aquatic

Species : activated sludge of a predominantly domestic sewage

Exposure period : 3 hour(s)

Unit : mg/l

EC50 : = 191 

Analytical monitoring : no

Method :

Year : 2000

GLP : yes

Test substance : other TS: Desmodur W, purity: 99.5 % (21.1 % trans,trans4,4'-methylenedicyclohexyl diisocyanate, 50.2 % trans,cis4,4'-methylenedicyclohexyl diisocyanate, and 28.2 % cis,cis4,4'-methylenedicyclohexyl diisocyanate

Method : Commission Directive 88/302/EEC, Official Journal of the EC L133, Part C:

Biodegradability: Test for inhibition of oxygen consumption (corresponds to

the OECD TG 209).

Remark : The described method for the preparation of test solution will lead to the

nearly complete hydrolysis of 4,4'-methylenedicyclohexyl diisocyanate and

to the formation of the hydrolysis product, 4,4'-methylenebis

(cyclohexylamine)

Test condition : - Before the incubation a pretreatment was performed with the test

substance according to the recommendation mentioned in the OECD

Guidance Document on aquatic toxicity testing of difficult substances and

mixtures. The test substance was added to about 130 ml deionised water,

treated 3-4 h by ultrasound and stirred overnight before testing

(equilibration phase)

- The following nominal concentrations were tested: 56, 100, 180, 320 and

560 mg/l

- The test concentration of activated sludge was 320 mg/l

- The pH-value of the suspension before application was 6.7

- Incubation time: 3 hours with permanent aeration.

- The test temperature was 20 +/- 2 °C

Reliability : (1) valid without restriction

GLP guideline study

Flag : Critical study for SIDS endpoint

22.12.2005 (25)

Type : aquatic

Species :

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OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

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DATE: 09.11.2006

Exposure period :

Unit : mg/l

EC3 : 80 

Method :

Year : 2003

GLP :

Test substance : other TS: Methylene bis(4-cyclohexyldiamine)

Result : The hydrolysis product, 4,4'-methylenebis(cyclohexylamine), has a low

ecotoxicity

Reliability : (2) valid with restrictions

Reliable source

Flag : Critical study for SIDS endpoint

22.12.2005 (58)

Type : aquatic

Species : activated sludge of a predominantly domestic sewage

Exposure period : 3 hour(s)

Unit : mg/l

EC50 : = 19 

Analytical monitoring : no

Method : ISO 8192 "Test for inhibition of oxygen consumption by activated sludge"

Year : 1992

GLP : yes

Test substance : other TS: Desmodur W, purity: 91.6 % (24.38 % trans,trans4,4'-methylenedicyclohexyl diisocyanate, 43.00 % trans,cis4,4'-methylenedicyclohexyl diisocyanate, and 24.20 % cis,cis4,4'-methylenedicyclohexyl diisocyanate

Remark : The test substance was not completely soluble in water at

all tested concentration levels.

This test has not been taken into account for the assessment of

4,4'-methylenedicyclohexyl diisocyanate. 4,4'-Methylenedicyclohexyl

diisocyanate is not a consumer product and may only be released into the

aquatic environment from manufacturing or processing. The aquatic halflife of this isocyanate is approximately 2 hours. Possible aquatic emissions

would enter a wastewater treatment plant with a hydraulic retention time of

several hydrolysis half-lives, which means that virtually all isocyanate

would hydrolyze to the corresponding amine during wastewater treatment

before it enters environmental waters. The hydrolysis product,

4,4'-methylenebis(cyclohexylamine), is virtually the only form of the test

substance in the aquatic environment. Thus, for assessment, not the

isocyanate, but its hydrolysis product has to be tested.

In the test at issue, the test substance was used immediately after contact

with water, and significant concentrations of the unhydrolyzed isocyanate

were present at the start of incubation. Thus, these test conditions do not

reflect environmental conditions, and were not used for assessment

Result : Test concentration* resperation rate Inhibition (mg/l)

(mg/l h) (%)

 0 22.2 0

 5.6 19.5 12.2

 10 16.0 27.9

 18 10.8 51.4

 32 7.0 68.5

 56 4.0 82.0

* nominal

Test condition : - The following nominal concentrations were tested: 5.6, 10, 18, 32 and 56

mg/l

- Type of application: Test substance stock emulsion was prepared by

70
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DATE: 09.11.2006

addition of 1 g/l of test substance into water and treatment with ultra-turrax

at 8000 rpm for 60 seconds. The emulsion was used for preparation of test

solutions by dilution of aliquots

- The concentration of inoculum was 6 g/l test substance

Reliability : (2) valid with restrictions

Comparable to guideline study with acceptable restrictions

18.01.2006 (14)

4.5.1 CHRONIC TOXICITY TO FISH

4.5.2 CHRONIC TOXICITY TO AQUATIC INVERTEBRATES

4.6.1 TOXICITY TO SEDIMENT DWELLING ORGANISMS

4.6.2 TOXICITY TO TERRESTRIAL PLANTS

4.6.3 TOXICITY TO SOIL DWELLING ORGANISMS

4.6.4 TOX. TO OTHER NON MAMM. TERR. SPECIES

4.7 BIOLOGICAL EFFECTS MONITORING

4.8 BIOTRANSFORMATION AND KINETICS

4.9 ADDITIONAL REMARKS

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OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

5. TOXICITY ID: 5124-30-1

DATE: 09.11.2006

5.0 TOXICOKINETICS, METABOLISM AND DISTRIBUTION

5.1.1 ACUTE ORAL TOXICITY

Type : LD50

Value : = 9900 mg/kg bw

Species : rat

Strain : Sprague-Dawley

Sex :

Number of animals : 5

Vehicle : other: corn oil

Doses : 6310, 7940, 10000, 12600 mg/kg

Method : other: see Test Condition 

Year : 1966

GLP : no

Test substance : other TS: 4,4 ́-methylenedicyclohexyl diisocyanate, no data on purity

Result : MORTALITY: 

Number of deaths at each dose: 6310 mg/kg: 0/5, 7940 mg/kg: 1/5, 10000

mg/kg: 3/5, 12600 mg/kg: 4/5

SURVIVAL TIME: 

One to four days

CLINICAL SIGNS:

severe diarrhea, loss of appetite and increasing weakness

NECROPSY:

Liver discoloration and renal hyperemia

Test condition : ADMINISTRATION: the test material was administered by stomach tube

as 50% solution-suspension in corn oil

sex: 5 animals per dose with alternate sex (e.g. 3 females and 2 males or 2

females and 3 males)

post observation period: no data

EXAMINATIONS: mortality, clinical signs and necropsy of the animals that

succumbed

CALCULATION OF LD50:

According to a modification of the method of E.J. de Beer

Reliability : (2) valid with restrictions

Limited documentation, no data on purity of test substance

Flag : Critical study for SIDS endpoint

22.12.2005 (77)

Type : other: ALD

Value : > 11000 mg/kg bw

Species : rat

Strain : other: ChR-CD

Sex : male

Number of animals :

Vehicle : peanut oil

Doses : 670, 2250, 3400, 5000, 7500, 11000 mg/kg

Method : other: no data 

Year : 1963

GLP : no

Test substance : other TS: 4,4 ́-methylenedicyclohexyl diisocyanate, no data on purity

Remark : ALD = Approximate lethal dose

Result : MORTALITY: no mortality

CLINICAL SIGNS: Initial weight loss; diarrhea, perineal discoloration,

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OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

5. TOXICITY ID: 5124-30-1

DATE: 09.11.2006

discomfort at levels of 2250 mg/kg and above

NECROPSY: Slight to moderate changes in kidney and brain at all doses;

injury to stomach and small intestine at 11000 mg/kg

Test condition : No. of Animals: no data

ADMINISTRATION: the test material was administered by stomach tube

as suspension in peanut oil in single doses

post observation period: 14d

EXAMINATIONS: mortality, clinical signs and necropsy

Reliability : (3) invalid

The documentation of the study is insufficient, i.e. the number of animals is

not mentioned

21.10.2004 (46)

5.1.2 ACUTE INHALATION TOXICITY

Type : LC50

Value : = 434 mg/m3

Species : rat

Strain : Wistar

Sex : male/female

Number of animals : 5

Vehicle : other: no

Doses : 151, 388, 418, 552, 730, 865, 1,352 mg/m3

Exposure time : 4 hour(s)

Method : OECD Guide-line 403 "Acute Inhalation Toxicity"

Year : 1985

GLP : yes

Test substance : other TS: 4,4 ́-methylenedicyclohexyl diisocyanate, purity > 99.2 %

Result : VALUE:

LC50 (male): 456 mg/m3 (95% confidence interval of 313 to 667 mg/m3)

LC50 (female): 431 mg/m3 (95% confidence interval of 363 to 513 mg/m3)

LC50 (male/female): 434 mg/m3 (95% confidence interval of 355 to 533

mg/m3)

MORTALITY:

Number of deaths at each dose (time of death), male rats: 151 mg/m3: 0/5;

388 mg/m3: 2/5 (1d-2d); 418 mg/m3: 2/5 (1d-2d); 552 mg/m3: 5/5 (1d-4d);

730 mg/m3: 4/5 (1d-3d); 865 mg/m3: 2/5 (1d-2d); 1,352 mg/m3: 5/5 (0d-1d)

Number of deaths at each dose (time of death), female rats: 151 mg/m3:

0/5; 388 mg/m3: 2/5 (1d); 418 mg/m3: 2/5 (1d); 552 mg/m3: 4/5 (1d-2d);

730 mg/m3: 5/5 (1d); 865 mg/m3: 5/5 (1d-3d); 1,352 mg/m3: 5/5 (0d-1d)

CLINICAL SIGNS:

Number of animals with clinical signs, male rats: >= 151 mg/m3: 5/5 (due to

early death at 1,352 mg/m3 clinical signs were only for 4/5 animals

recorded) showed during the exposure and up to 12d after the exposure

bradypnea, dyspnea, laboured breathing, rales, irregular breathing pattern,

ungroomed coat, piloerection, motility reduced, tremor, hunched posture,

highlegged gait, staggered gait, sluggish, cyanosis, vocalization,

emaciation, serous discharge from nose, reddish rhinarium, wheezing,

nose with red encrustations, nose-Muzzle/red encrustations, prostration

(lying on belly); at the end of the post observation period all surviving

animals were without symptoms

Number of animals with clinical signs, female rats: >= 151 mg/m3: 5/5 (due

to early death at 1,352 mg/m3 clinical signs were only for 4/5 animals

recorded) showed during the exposure and up to 9d after the exposure

bradypnea, dyspnea, laboured breathing, rales, irregular breathing pattern,

ungroomed coat, piloerection, motiltiy reduced, tremor, hunched posture,

highlegged gait, staggered gait, sluggish, cyanosis, vocalization,

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OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

5. TOXICITY ID: 5124-30-1

DATE: 09.11.2006

emaciation, serous discharge from nose, reddish rhinarium, wheezing,

nose with red encrustations, nose-Muzzle/red encrustations, prostration

(lying on belly); at the end of the post observation period all surviving

animals were without symptoms

BODY WEIGHT:

>= 151 mg/m3: body weight retardation

RECTAL TEMPERATURE:

concentration dependent decrease

REFLEX EXAMINATION:

no substance induced effects

NECROPSY:

rats died during the post observation period:

pale liver, spleen and kidneys, lobular pattern of the liver, duodenum was

filled with a red mucous mass, trachea was filled with a mucous mass, less

collapsed lungs with red foci, pulmonary edema and hydrothorax; lungs

were red up to hepatoid changes, red secretions in the nose 

rats sacrificed at the end of the post observation period:

>= 151 mg/m3 no specific concentration dependent organ changes

Test condition : ADMINISTRATION:

vapour inhalation under dynamic head-nose only exposure conditions

post observation period: 2 weeks

nominal concentrations: 667, 1,167, 1,333, 1,667, 2,500, 3,333, 6,667

mg/m3

chamber concentration: 

Analysis of the test atmosphere:

the chamber samples were taken in the vicinity of the breathing zone and

the test-substance concentration was determined by HPLC (test material

was collected in a glass tube filled with mineral wool which was

impregnated with a nitrocompound to react in situ with the diisocyanate)

and by gravimetric analysis (filter: Glass Fibre-Filter)

the analytical values determined by HPLC < the analytical values

determined gravimetrically

the analytical values were 20 to 33% of the nominal concentration; 

particle size distribution: 

90% of the particle mass with an aerodynamic diameter <= 3 μm 

mass median aerodynamic diameter (MMAD) » 1.4 μm; geometric

standard deviation (GSD) » 1.8 μm

EXAMINATIONS:

mortality; clinical signs; body weight; rectal temperature, reflex, necropsy

CALCULATION OF LC50:

according to A.P. Rosiello et al., J. Tox. and Environ. Health 3, 797-809

(1977) and modified by J. Pauluhn; Bayer Report No. 11845 (1983)

Reliability : (1) valid without restriction

Flag : Critical study for SIDS endpoint

14.01.2005 (18)

Type : LC50

Value : 295 307 mg/m3

Species : rat

Strain : Sprague-Dawley

Sex : male/female

Number of animals : 10

Vehicle : other: no

Doses : 191, 113, 307, 288, 340, 608 mg/m3

Exposure time : 4 hour(s)

Method : other: see Test Condition 

Year : 1985

GLP : yes

Test substance : other TS: see Test substance

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5. TOXICITY ID: 5124-30-1

DATE: 09.11.2006

Result : VALUE:

LC50 (male): 295 mg/m3 (95% confidence interval of 221 to 380 mg/m3)

LC50 (female): 307 mg/m3 (95% confidence interval of 268 to 327 mg/m3)

NOEL: < 113 mg/m3

the result for 191 mg/m3 was not used in calculating the LC50

MORTALITY: 

Number of deaths at each dose (time of death), male rat: 113 mg/m3: 1/10

(1d), 191 mg/m3: 0/10, 288 mg/m3: 5/10 (1d), 307 mg/m3: 3/10 (0-1d), 340

mg/m3: 7/10 (1-2d), 608 mg/m3: 10/10 (0-1d)

Number of deaths at each dose (time of death), female rat: 113 mg/m3:

0/10, 191 mg/m3: 0/10, 288 mg/m3: 3/10 (1-3d), 307 mg/m3: 4/10 (1d), 340

mg/m3: 9/10 (1-2d), 608 mg/m3: 10/10 (0-1d)

CLINICAL SIGNS:

number of animals with clinical signs (male/female): 10/10 >= 113 mg/m3

nasal and ocular irritation during exposure and

post-exposure. Some of the animals exposed to 307, 340 and 608 mg/m3

air showed salivation, lacrimation, decreased activity, occasional tremors

and corneal opacity. The clinical signs lasted up to ten days in both male

and female animals. Difficulty in breathing was also observed in animals

when they were taken out of the tubes. Most of the surviving animals

exhibited alopecia of varying degree in areas that were in contact with the

compound during the exposure. The alopecia was noticed on day 2 or 3

and lasted until the end of the study. Neck edema observed in animals was

related to the mode of exposure and not to the compound.

BODY WEIGHT:

The group mean body weights of male animals exposed to test material

were significantly lower than those of the control group on days 2, 3 and 4

at concentrations 113 and 288 mg/m3 air, on days 2 through 7 at

concentration 340 mg/m3 air and on days 2 through 14 at concentration

307 mg/m3 air.

The group mean body weights of compound-exposed females were

significantly lower on day 2 at exposure concentration 191 mg/m3 air, and

on days 2 through 4 at concentrations 288, 307 and 340 mg/m3 air.

NECROPSY and HISTOPATHOLOGY:

Compound-related gross lesions observed in most of the animals sacrificed

at term included alopecia of the ear and head skin (the areas directly

exposed to test material) and occasional crusty zones. The gross lesions

observed in the animals that died during 01: after compound exposure

were agonal changes and included lacrimation, dark pink or red lungs,

yellow or red nasal discharge, reddened turbinates and gas-filled

intestines. Other gross lesions observed in control and compound-exposed

animals were incidental and distributed randomly in both groups.

Microscopic examination of the ear and skin lesions showed that the

severity of ear lesions was concentration-related (P<O.O5). The lesions

consisted of acanthosis, chronic or chronic-active inflammation and

Langhan's giant cells with phagocytized hair and foamy cytoplasm. These

lesions occurred in the ears and skin of several sacrificed animals at all but

the lowest concentration level and probably represent a foreign body

reaction initiated by debris contaminating the dermis through overlying

ulcers. Exposed animals that died during the study had no ear or skin

lesions which might reflect a shorter exposure time to the compound.

Lesions of lung, liver, and kidney were lesions were toxicologically

nonsignificant since they were seen in both controls and exposed animals

(sacrificed and found dead) or were seen only in control animals.

Test condition : ADMINISTRATION:

Test material was generated as a liquid aerosol by an apparatus that

consisted of two concentric nozzles. The test material was conducted into a

fine inner nozzle by an infusion pump at a constant rate. Animals were

exposed under dynamic conditions in a 60-liter cylindrical chamber. In the

middle portion of the chamber were two rows of ten tubes each, which

75
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

5. TOXICITY ID: 5124-30-1

DATE: 09.11.2006

were attached radially to the chamber. The animals were individually

positioned in these tubes so that only their heads were exposed to the test

material while their bodies remained within perforated tubes.

post observation period: 14 days

nominal concentrations: 

500, 750, 1,000, 1,240, 1,500 and 1,750 mg/m3

chamber concentration:

Analysis of the test atmosphere: 

Analytical concentration of the chamber atmosphere was determined by

taking samples near the animal breathing zone; 1.5 to 3-liter samples were

taken at 15 minute intervals; samples were drawn through Millipore FH

(pore size 0.5 um) filters at a rate of 1.5 l/min; the contents of the filter were

determined by HPLC. 

The analytical values were 23 to 38% of nominal concentration, except for

one value (113 mg/m3) which was only 15%.

particle size distribution: 

50% of the particle mass had mass median aerodynamic diameter (MMAD)

below 2 μm; about 90% of the particle mass had MMAD less than 6.6 μm

EXAMINATIONS:

mortality, clinical signs approximately (three to four times post-exposure

(on day of exposure) and then twice daily up to 14 days), body weights

(prior to exposure and on days 2, 3, 4, 7 and 14 after exposure), necropsy,

histopathology (lungs, liver, kidneys from animals exposed to 113, 119, 288

and 340 mg/m3).

CALCULATION OF LC50:

The LC50 values with 95% confidence limits were calculated by probit

analysis. During sampling. higher recoveries (30.7%) were seen at 307

mg/m3 air concentration (nominal 1,000 mg/m3 air) and lower recoveries

(23.2%) at 288 mg/m3 air (nominal 1,240 mg/m3 air. This reflected higher

mortality at the low concentration and lower mortality at the high

concentration, which made it difficult to calculate the LC50. Therefore, the

concentrations of 288 and 307 mg/m3 air and their corresponding

mortalities were averaged in calculating LC50 values.

Test substance : 4,4 ́-Methylenedicyclohexyl diisocyanate, technical grade, no further data

Reliability : (2) valid with restrictions

Due to the method applied for the analysis of the test atmosphere the

values for the analytical concentrations underestimate the actual exposure

concentration because the test sample partly would have been captured by

reaction with the filter material and/or humidity; no replicate of the

determination using another detection method (e.g. gravimetric analysis)

was performed

Flag : Critical study for SIDS endpoint

06.11.2006 (76)

Type : other

Value : 

Species : rat

Strain : other: ChR-CD

Sex : male

Number of animals : 4

Vehicle : other: no

Doses :

Exposure time : 4 hour(s)

Method : other: see Test Condition 

Year : 1963

GLP : no

Test substance : other TS: 4,4 ́-methylenedicyclohexyl diisocyanate, no data on purity

Result : MORTALITY RATIO:

76
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

5. TOXICITY ID: 5124-30-1

DATE: 09.11.2006

 0/4 (200 °C); 2/4 (250 °C); 2/4 (300 °C)

OBSERVATIONS:

At the 250 and 300 °C level the rats exhibited gasping, labored respiration,

ruffled fur, extremely red extremities, eye irritation and lacrimation. In

addition to CO, white fumes were observed in the exposure chamber.

At the 200 °C level the animals showed slightly deep respiration, red

extremities, eye irritation and lacrimation. Neither CO nor fumes were

detectable in the exposure chamber at 200 °C.

Test condition : approx. 20 grams of material was placed in a flask and heated to and

maintained at the required temperature (200, 250, 300 °C) in a heating

mantle. A dry air stream passed through the flask to a 8-liter bell jar

containing the rats; survivors killed 14 days later;

nominal concentration:

12,1 mg/m3 (300 °C); 11,1 mg/m3 (250 °C); 10,4 mg/m3 (200 °C)

(computed from weight loss of sample and air flow)

Reliability : (3) invalid

Due to the high temperature decomposition of the test material cannot be

excluded; nominal exposure was not verified analytically; whole body

exposure

14.01.2005 (46)

Type : other

Value : 

Species : rat

Strain : other: ChR-CD

Sex :

Number of animals : 4

Vehicle : other: butyl acetate

Doses :

Exposure time : 1 hour(s)

Method : other: see Test Condition 

Year : 1968

GLP : no

Test substance : other TS: 4,4 ́-methylenedicyclohexyl diisocyanate, no data on purity

Result : During exposure no clinical signs of respiratory irritation were seen;

immediate reddening of the rat ears followed over a 14-day period by

swelling of the ears, sluffing of the outer ear skin and its regeneration. This

was accompanied by microscopically identifiable edems and congestion of

the ear skin layers which was still midly evident 14 days after exposure, the

test material caused tracheitis and brinchitis which was healing 7 days after

exposure and had healed 14 days after exposure

nominal isocyanate concentration: 2,85 mg/m3

Test condition : The test material was dissolved in commercial butyl acetate , the test

solution was sprayed at the same uniform rate into the exposure chamber

throughout the exposure, the solutions were sprayed with stainless steel

paint spray nozzle using house air. Control rats were similary exposed to

butyl acetate only. Droplet size distribution was measured with Monsanto

cascade impactor; 2 rats were sacrified for gross and histopathologic

examination at each of 7 and 14 days post-exposure; tissue examined

were lung, liver, brain, spleen, kidney, testes, stomach, thymus, thyroid,

adrenal, ear and bone marrow.

Reliability : (3) invalid

Due to lack of study documentation and study design and unreliable

exposure analysis

14.01.2005 (47)

Type : other: Class B Poison Test

Value : 

Species : rat

77
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

5. TOXICITY ID: 5124-30-1

DATE: 09.11.2006

Strain : other: ChR-CD

Sex : male

Number of animals : 10

Vehicle : other: no

Doses :

Exposure time :

Method : other: see Test Condition 

Year : 1972

GLP : no

Test substance : other TS: Hylene W, no data on purity

Result : The test material is not a Class B Poison by inhalation as

defined by the Department of Transportation

Test condition : Exposure No. 1:

approx. 100 grams of the test material was maintained at room

temperature in a round-bottomed flask. Dry houseline air was passed over

the material and into a 20-liter exposure chamber containing the rats.

Samples of the chamber atmosphere were taken at least three times during

exposure and analyzed using a colorimetric method. Neither gross nor

histopathologic examination was performed on any animals tested

Exposure No. 2:

Procedure same as above with one modification: houseline air was passed

into the flask through a stainless steel nobulizer to generate aerosol and

test material was heated at 62-75 °C

Reliability : (3) invalid

Methodological deficiencies, analytical detection method and/or the

generation of the test atmosphere are unrealiable because the analytical

concentrations ranged from 0.005 -0.514 mg/l for several exposures which

were conducted under identical conditions

22.10.2004 (50)

Type : other: inhalation hazard test

Value : 

Species : rat

Strain : no data

Sex : male

Number of animals : 4

Vehicle : other: no

Doses : no data

Exposure time : 6 hour(s)

Method : other: see Test Condition 

Year : 1966

GLP : no

Test substance : other TS: 4,4 ́-methylenedicyclohexyl diisocyanate, no data on purity

Result : MORTALITY:

All animals survived the exposure as well as the following observation

period

CLINICAL SIGNS:

reduced activity and occasional changes in breathing rate were the only

outward evidence of toxicity. Nasal and ocular mucosae were not

inflammed and there was no weakness; activity and appearance were

normal in 24 hours. No complications developed during the ten day

observation period

Test condition : The animals (whole body exposure) were exposed to a concentrated

atmosphere of vapors produced by passing a stream of air through 100 ml

of the compound contained in a 250 ml Erlenmeyer flask, vapors from the

flask passed into a one liter bottle to remove droplets and then into the

chamber

Average temperature inside the chamber: 75oF 

78
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

5. TOXICITY ID: 5124-30-1

DATE: 09.11.2006

Average relative humidity inside the chamber: 63%

post observation period: 10 days

Reliability : (3) invalid

Due to lack of study documentation and exposure analysis; whole body

exposure

22.10.2004 (77)

Type : other: RD50 (sensory irritation)

Value : = 27 mg/m3

Species : mouse

Strain : CD-1

Sex : male

Number of animals : 4

Vehicle : other: acetone

Doses : 8, 8, 18, 20, 19, 36, 48, 72, 93 mg/m3

Exposure time : 3 hour(s)

Method : other: see Test Condition 

Year : 1984

GLP : yes

Test substance : other TS: 4,4 ́-methylenedicyclohexyl diisocyanate, commercial grade, no

further data

Result : VALUE:

RD50 = 27 mg/m3 (95% confidence limits: 18 to 36 mg/m3)

MORTALITY: 1⁄4 at 20, 48 and 93 mg/m3

CLINICAL SIGNS: 

Number of animals with clinical signs (duration of symptoms): 8 mg/m3:

0/4, 8 mg/m3: 0/4, 18 mg/m3: 2/4 (during exposure up to 3d), 20 mg/m3: 1⁄4

(during exposure up to 1d), 19 mg/m3: 1⁄4 (during exposure up to 1d), 36

mg/m3: 4/4 (during exposure up to 1d), 48 mg/m3: 3⁄4 (during exposure up

to 3d), 72 mg/m3: 4/4 (during exposure up to 1d), 93 mg/m3: 4/4 (during

exposure up to 7d)

The signs of toxicity were concentration-related and included difficulty in

breathing, decreased activity, tremors and ataxia and lasted from one to

three days except at 93 mg/m3 where one mouse showed labored

breathing on days 6 and 7 and was found dead prior to necropsy.

BODY WEIGHT: no compound related effect

RESPIRATORY RATE:

The time-response relationships show an increase in the respiratory rate in

the beginning of exposure followed by a decrease in the respiratory rate

reaching maximum decrease by the end of the three-hour exposure. This

pattern of response was more clear at the lower concentration (8 mg/m3)

where only an increase in the respiratory rate was observed. An increase in

the respiratory rate is indicative of deep lung irritation (pulmonary irritation),

whereas a decrease in respiration rate indicates irritation of the upper

respiratory tract (sensory irritation). The animal responses to the test

material exhibited irritation of both the upper and lower respiratory tract.

NECROPSY:

No compound-related gross lesions were observed in any of the animals. A

random lesion noted was gas and fluid filled intestines in one animal

exposed to 20 mg/m3.

Test condition : ADMINISTRATION:

Test material was generated as liquid aerosol. Desired concentrations of

aerosol atmosphere were generated by using 0.3 to 4.85% (w/w) solution

of Desmodur W in acetone, head-only exposure chambers were used; no

concurrent acetone or air control groups were used during the study. The

acetone and air control data used is from a similar study using the same

strain of mice. The data show that no significant effect on the respiratory

rate of animals was observed due to the use of acetone as the solvent or to

the method of exposure (air control).

79
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

5. TOXICITY ID: 5124-30-1

DATE: 09.11.2006

post-observation period: 7 days

nominal concentrations: 23, 37, 51, 75, 90, 100, 160, 245, 388 mg/m3

EXAMINATIONS:

mortality, clinical signs, body weight, body plethysmography, necropsy

Reliability : (3) invalid

Unsuitable test for aerosols because the generation of the test atmosphere

(-> particle size distribution) determines the pattern of the test material

deposit in the respiratory tract and thus the response, therefore no reliable

conclusion is possible; test (RD50 determination) is restricted to vapours

(upper tract irritant)

14.01.2005 (75)

Type : other: RD50 (sensory irritation)

Value : = 4 mg/m3

Species : mouse

Strain : Swiss Webster

Sex : male

Number of animals : 4

Vehicle : other: acetone

Doses : 16.7, 288 , 379, 505, 669 mg/m3

Exposure time : 4 hour(s)

Method : other: see Test Condition 

Year : 1985

GLP : no data

Test substance : other TS: 4,4 ́-methylenedicyclohexyl diisocyanate, purity 99.3 % minimum

Remark : To confirm the pulmonary irritation properties mice were exposed via

tracheal cannula (414 mg/m3) which will eliminate sensory irritation and

pulmonary irritation can be studied alone. A decrease in respiratory

frequency was observed, indicating that the test material acts as pulmonary

irritant.

Result : VALUE:

RD50 = 40 mg/m3

RESPIRATORY RATE: decline dependence on both the duration of

exposure and the exposure concentration

LUNG WEIGHT: increase with exposure concentration

Test condition : ADMINISTRATION:

The test material was generated as liquid aerosol. Desired concentrations

of aerosol atmosphere were generated by using 0.25 to 1.5% solution of

test material in acetone; the chamber concentrations were determined

gravimetrically

post-observation period: all animals were killed 24 hr postexposure

EXAMINATIONS:

body plethysmography, lung weight

Reliability : (3) invalid

Limited documentation; test system unsuitable for aerosols because the

generation of the test atmosphere (-> particle size distribution) affects the

pattern of test sample deposit in the respiratory tract and thus the

response; therefore no reliable conclusion is possible; test (RD50

determination) is restricted to vapours (upper tract irritants)

14.01.2005 (95)

Type : LC50

Value : 51 mg/m3

Species : guinea pig

Strain : other: English smooth-haired

Sex : male/female

Number of animals : 5

Vehicle : other: no

Doses : 0, 17, 44, 55, 90 mg/m3

80
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

5. TOXICITY ID: 5124-30-1

DATE: 09.11.2006

Exposure time : 1 hour(s)

Method : other: see Test Condition 

Year : 1982

GLP : no

Test substance : other TS: 4,4 ́-methylenedicyclohexyl diisocyanate, no data on purity

Result : VALUE:

LC50 (male/female): 51 mg/m3 (95% confidence interval = 36 to 72

mg/m3)

MORTALITY:

Number of deaths at each dose (time of death), male rats: 17 mg/m3: 0/5,

44 mg/m3: 0/5, 55 mg/m3: 3/5 (2-3d), 90 mg/m3: 5/5 (1-3d)

Number of deaths at each dose (time of death), female rats: 17 mg/m3: 1/5

(4d), 44 mg/m3: 1/5 (2d), 55 mg/m3: 2/5 (3d), 90 mg/m3: 4/5 (1-2d)

CLINICAL SIGNS:

The most frequent clinical signs, observed during the first three days of the

study, consisted of pallor of the skin or cyanosis, respiratory distress,

weakness or lethargy, and nasal discharge (no information on number of

animals with clinical signs per concentration and sex)

BODY WEIGHT:

body weight losses occurred in all treated groups except for males exposed

to the lowest concentration. Body weight losses were made good by the

end of the first week of the observation period

ANTIBODY ANALYSIS: no information available 

NECROPSY:

marked gross changes in the lungs such as rubbery texture, swelling and

reddening were observed in the animals that died.

Test condition : ADMINISTRATION:

The test material was generated as a liquid aerosol by using a concentric

jet glass atomizer supplied with predried compressed air. The animals were

positioned in plexiglas whole-body exposure chambers.

post observation period: 14 days

nominal concentrations (calculated from the weight loss from the generator

and the total airflow through the chamber during the 1-hour exposure

period): 70, 90, 140, 240 mg/m3

EXAMINATIONS:

mortality, clinical signs, body weights, antibody analysis, necropsy

CALCULATION OF LC50:

The LC50 value and the 95% confidence interval were calculated using the

method of Litchfield and Wilcoxon, Journal of Pharamacology &

Experimental Therapeutics, 1949, 96 (2), 99-113.

Reliability : (3) invalid

Significant methodological deficiencies (i.e. whole body exposure) and

limited documentation

14.01.2005 (3)

5.1.3 ACUTE DERMAL TOXICITY

Type : other: skin absorption MLD

Value : > 10000 mg/kg bw

Species : rabbit

Strain : New Zealand white

Sex : male/female

Number of animals : 1

Vehicle : other: corn oil

Doses : 1000, 1580, 2510, 3980, 6,310, 10000 mg/kg

Method : other: see Test Condition 

Year : 1966

81
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

5. TOXICITY ID: 5124-30-1

DATE: 09.11.2006

GLP : no

Test substance : other TS: 4,4 ́-methylenedicyclohexyl diisocyanate, no data on purity

Result : no mortality up to 10000 mg/kg; activity and appetite were reduced for

several days after 6130 and 10000 mg/kg, there was moderate weakness

but no paralysis

Test condition : The undiluted sample (6130 and 10000 mg/kg) and diluted sample (50%

solution/suspension in corn oil) was applied to the closely clipped intact

skin of a male or female rabbit. The treated areas were covered with plastic

strips and the animals placed in wooden stocks for 24 hours; observations

were made for toxic symptoms and since there were no deaths, no

autopsies were performed 

post observation period: no data

Reliability : (2) valid with restrictions

Limited documentation, only one animal per dose with alternate sex, no

data on purity of test substance

Flag : Critical study for SIDS endpoint

22.10.2004 (77)

Type : other: Class B Poison Test

Value : 

Species : rabbit

Strain : no data

Sex : male

Number of animals : 6

Vehicle : other: no

Doses : 200 mg/kg

Method : other: see Test Condition 

Year : 1972

GLP : no

Test substance : other TS: 4,4 ́-methylenedicyclohexyl diisocyanate, no data on purity

Result : After a 24-hour exposure of 200 mg/kg b.w. 0/6 animals died; no clinical

signs were observed

Test condition : The test material was applied to the intact clipped dorsal skin. The rabbits

trunks were then wrapped with a layer of Saran wrap, stretch gauze

bandage and elastic adhesive tape. After 24-hour exposure period, the

wrapping were removed and the skin was washed with water and dried.

The animals were observed for a further 48 hours.

Reliability : (3) invalid

Limited documentation and only one dose group tested

22.10.2004 (49)

5.1.4 ACUTE TOXICITY, OTHER ROUTES

5.2.1 SKIN IRRITATION

Species : rabbit

Concentration : 500 other: ul

Exposure : Occlusive

Exposure time : 4 hour(s)

Number of animals : 6

Vehicle : other: no

PDII :

Result : moderately irritating

Classification :

Method : OECD Guide-line 404 "Acute Dermal Irritation/Corrosion"

82
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

5. TOXICITY ID: 5124-30-1

DATE: 09.11.2006

Year : 1981

GLP : no

Test substance : other TS: 4,4 ́-methylenedicyclohexyl diisocyanate liquid sample, no data

on purity

Result : A primary irritation value of 4.2 was calculated (3.1 - 5.0 = moderately

irritating);

retrogression after 8d to the level of a slight irritation (surface, parchmentlike skin scaling)

Test condition : test substance was applied on the flank skin on both sides of the body of

each animal; the determination of findings followed immediately after

removal of the cloths and washing (water) of the application site (4 h

value), then after 24, 48 and 72 h and after 8 d. The 24 and 72 h values are

the basis for the irritancy index; the 24 and 72 h levels of erythema and

edema formation in both test areas were averaged for the test animals; the

eight average values were divided by four, to yield the primary skin irritation

index

Reliability : (2) valid with restrictions

No data on purity of test substance

Flag : Critical study for SIDS endpoint

20.11.2004 (8)

Species : rabbit

Concentration : 500 other: mg

Exposure : Occlusive

Exposure time : 4 hour(s)

Number of animals : 6

Vehicle :

PDII :

Result : moderately irritating

Classification :

Method : OECD Guide-line 404 "Acute Dermal Irritation/Corrosion"

Year : 1981

GLP : no

Test substance : other TS: 4,4 ́-methylenedicyclohexyl diisocyanate, solid sample, no data

on purity

Result : A primary irritation value of 3.6 was calculated (3.1 - 5.0 = moderately

irritating);

retrogression after 8d to the level of a slight irritation (surface skin scaling)

Test condition : test substance (moistened in oil) was applied on the flank skin on both

sides of the body of each animal; the determination of findings followed

immediately after removal of the cloths and washing (water) of teh

application site (4 h value), then after 24, 48 and 72 h and after 8 d. The 24

and 72 h values are the basis for the irritancy index; the 24 and 72 h levels

of erythema and edema formation in both test areas were averaged for the

test animals; the eight average values were divided by four, to yield the

primary skin irritation index

Reliability : (2) valid with restrictions

No data on purity of test substance

Flag : Critical study for SIDS endpoint

20.11.2004 (9)

Species : rabbit

Concentration : 500 other: ul

Exposure : Semiocclusive

Exposure time : 4 hour(s)

Number of animals : 1

Vehicle :

PDII :

83
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

5. TOXICITY ID: 5124-30-1

DATE: 09.11.2006

Result :

Classification :

Method : OECD Guide-line 404 "Acute Dermal Irritation/Corrosion"

Year : 1994

GLP : yes

Test substance : other TS: 4,4 ́-methylenedicyclohexyl diisocyanate, purity > 99.2 %

Result : RESULT: "severely irritating to the skin" On the exposed skin strong

erythematous and exsudative reactions were observed. From day 7 on a

white to yellowish squamous coat (on day 14 the coat was white) and

eschar formation were seen. On day 14 on the exposed skin area the

epidermis was partly removed.

SCORE:

Erythema (observation time): 2 (1h, 72h, 7d)); 3 (24h, 48h, 14d)

Edema (observation time): 2 (1h, 24h); 1 (48h, 72h, 7d), 0 (14d)

mean value "erythema": 2.7

mean value "edema": 1.3

Test condition : For reasons of animal welfare, due to the expected irritant potency of the

test substance on the skin, in the test only one animal was used.

The scores at the reading times 24, 48, 72 hours for an effect were used in

calculating respective mean values.

Reliability : (1) valid without restriction

Flag : Critical study for SIDS endpoint

06.11.2006 (17)

Species : rabbit

Concentration : 500 other: ul

Exposure : Semiocclusive

Exposure time :

Number of animals : 3

Vehicle :

PDII :

Result : irritating

Classification :

Method : other: see Test Condition 

Year : 1996

GLP : yes

Test substance : other TS: 4,4 ́-methylenedicyclohexyl diisocyanate, purity: 99.89%

Result : There was no evidence of corrosion observed at any of the test sites for

any of the exposure periods (3-minutes, 1 -hour, and 4-hours).

Dermal irritation was observed sporadically from the 4-hour observations

(for the 4-hour exposure sites) through the 72-hour observations and at

most exposure sites from the 96-hour observations through the Day 14

observations. This dermal irritation was characterized by very slight to welldefined erythema (scores of l to 2) and very slight to slight edema (scores

of 1 to 2). On Day 21, all signs of edema had subsided and only one animal

was noted with very slight erythema at all exposure sites. However, on Day

21, areas of thickened skin were observed at the exposure sites for two

animals (all exposure sites for Animal No. 4022 and the 3-minute exposure

site for Animal No. 4023).

There were no remarkable signs of clinical toxicity and/or ill health noted

during the course of this study. All animals gained weight over the course

of the study.

Test condition : TEST ANIMALS:

strain: New Zealand White albino 

sex: male

EXPOSURE TIME: 3 minute, 1-hour and 4-hours

ADMINISTRATION/EXPOSURE:

The undiluted test material was applied to three separate test areas on the

84
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

5. TOXICITY ID: 5124-30-1

DATE: 09.11.2006

intact skin on each animal's back. Each area of application was covered

with a 2.5-cm x 2.5-cm gauze patch secured with Paper

tape, loosely overwrapped with Gran Wrap, and secured with Elastoplast

tape to provide a semiocclusive dressing. The wrappings applied to each

test site were independent of the other sites. Each animal was exposed to

the test material for 3-minute, 1 -hour, and 4-hour periods of time. At the

end of the 3-minute, 1 -hour, or 4-hour exposure periods, the patches were

removed and the test sites were washed using tap water. The test material

was removed from the test sites as thoroughly as possible without irritating

the skin.

EXAMINATIONS:

At the end of the 3-minute, 1 -hour, or 4-hour exposure periods, one patch

from each animal was removed and the treated area was examined for

evidence of corrosion. Corrosion is characterized by irreversible alterations

at the site of contact which may include ulceration and necrosis; changes

such as edema, erythema, sloughing of the epidermis, and tissuring alone

do not constitute corrosion. After the initial corrosion examination, the

residual test material was removed using tap water to prevent further test

material exposure. After removal of the patches, each application site was

examined for erythema and edema reactions according to the Draize

technique (recorded as the 3-minute, 1 -hour, or 4-hour Score).

Subsequent examinations were made at 24,48,72, and 96 hours and days

7, 14, and 21. Each site per animal (3-minute, 1-hour, and 4-hour exposure

sites) was scored independently at these timepoints. The untreated skin of

each animal was used for comparison. Photographs were taken of all

exposure sites for each animal and all exposure times for each animal, and

a sample of untreated skin, were preserved for future possible microscopic

evaluation.

Animals were also observed for signs of clinical toxicity and/or ill health at

each interval of dermal irritation scoring; these observations were recorded

by exception.

Reliability : (1) valid without restriction

Flag : Critical study for SIDS endpoint

22.10.2004 (26)

Species : rabbit

Concentration : 500 other: ul

Exposure : Semiocclusive

Exposure time : 4 hour(s)

Number of animals : 6

Vehicle :

PDII :

Result : corrosive

Classification :

Method : other: see Test Condition 

Year : 1973

GLP : no

Test substance : other TS: Hylene W, no data on purity

Result : According to the regulation of the Department of Transportation

(Department of Transportation, Hazardous Materials Regulations Board,

Docket No. HM-57, Federal Register, Vol. 38, no.28, section 173.240,

February 12, 1973) Hylene W is considered a corrosive material

4/6 rabbits with corrosion (no further information)

Test condition : the test material was applied to intact skin of 6 animals; after 4 hours the

wrapping and gauze pads were removed and any skin reactions were

evaluated; the test sites were washed, readings were again made 24 and

48 hours after initial application

Reliability : (4) not assignable

Individual animal data are not reported, no data on primary skin irritation

85
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

5. TOXICITY ID: 5124-30-1

DATE: 09.11.2006

indices, exposure sites were only observed at 24 and 48 hours

22.10.2004 (51)

Species : guinea pig

Concentration :

Exposure :

Exposure time : 24 hour(s)

Number of animals : 10

Vehicle : other: yes

PDII :

Result :

Classification :

Method : other: the test material was applied to intact skin of 10 animals as a

solution in aceton: dioxane (1:1) containing 13% guinea pig fat (f.a.d.) 

Year : 1963

GLP : no

Test substance : other TS: 4,4 ́-methylenedicyclohexyl diisocyanate, no data on purity

Result : 24-hour reaction: strong erythema and edema (5%), 

strong erythema (0,5%), no irritation (0,05%)

Reliability : (3) invalid

Unsuitable test system

25.10.2004 (46)

Species : guinea pig

Concentration : 50 other: ul

Exposure :

Exposure time : 24 hour(s)

Number of animals : 3

Vehicle : other: acetone

PDII :

Result :

Classification :

Method : other: see Test Condition 

Year : 1977

GLP : no

Test substance : other TS: Hylene W, no data on purity

Result : 24 hour reaction: moderate irritation (50%, 25%) and mild

irritation (10%, 5%)

Test condition : TEST ANIMALS:

strain: albino

sex: male

ADMINISTRATION/EXPOSURE:

One drop (= 0.05 ml) each of a 50%, 25%, 10% and 5% acetone solution

was applied and lightly rubbed into the shaved intact back skin.

EXAMINATIONS:

Readings were made 24 hours after the topical applications.

Reliability : (3) invalid

Unsuitable test system

25.10.2004 (55)

Species : guinea pig

Concentration : 50 other: ul

Exposure : no data

Exposure time :

Number of animals : 10

Vehicle : other: acetone

PDII :

Result :

86
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

5. TOXICITY ID: 5124-30-1

DATE: 09.11.2006

Classification :

Method : other: see Test Condition 

Year : 1977

GLP : no

Test substance : other TS: Hylene W, no data on purity

Remark : A range-finding study was done on 3 animals with 50%, 25%, 10% and 5 %

testmaterial in acetone, after 24 hours 3/3 animals showed mild (5% and

10%) or moderate (25% and 50%) erythema

Result : 24 and 48 hour reaction: slight (8/10 and 6/10) to no reaction (0,5%), no

irritation (0,05%)

Test condition : TEST ANIMALS:

strain: albino

sex: male

ADMINISTRATION/EXPOSURE:

One drop (= 0.05 ml) each of a 0.5% and 0.05% solution of test material in

acetone was applied and lightly rubbed into the shaved intact shoulder

skin.

EXAMINATIONS:

Readings were made 24 and 48 hour(s) after application

Reliability : (3) invalid

Unsuitable test system

25.10.2004 (54)

Species : rabbit

Concentration : undiluted

Exposure : Occlusive

Exposure time : 24 hour(s)

Number of animals : 3

Vehicle :

PDII :

Result : moderately irritating

Classification :

Method : other: see Test Condition 

Year : 1966

GLP : no

Test substance : other TS: 4,4 ́-methylenedicyclohexyl diisocyanate, no data on purity

Result : The compound was classed as a moderate irritant; the average maximum

score was 4.3 out of a possible 8 in 24 hours, within 7 days edema

disappeared but mild redness remained.

Test condition : TEST ANIMALS:

strain: albino

sex: 1 male, 2 females

ADMINISTRATION/EXPOSURE:

The undiluted compound was applied to the clipped, intact skin and

removed after 24 hours. The application was covered with plastic strips

EXAMINATION:

observations were made at the end of 1 hour, 24, 48, 72, 120 and 168

hours; the data were scored according to the method of Draize.

Reliability : (4) not assignable

Limited documentation, e.g. no data on applicated volume, no individual

scores are reported

25.10.2004 (77)

5.2.2 EYE IRRITATION

Species : rabbit

87
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

5. TOXICITY ID: 5124-30-1

DATE: 09.11.2006

Concentration : undiluted

Dose : 100 other: ul

Exposure time :

Comment : other: rinsed after 30 sec./not rinsed

Number of animals : 6

Vehicle :

Result : irritating

Classification :

Method : OECD Guide-line 405 "Acute Eye Irritation/Corrosion"

Year : 1981

GLP : no

Test substance : other TS: 4,4 ́-methylenedicyclohexyl diisocyanate liquid sample, no data

on purity

Result : A primary irritation value of 3.0 was calculated (0 - 10 = not irritating); with

regard to the results the test material was classified "not irritating", however

there were slight effects on the conjunctivae (grade 1-2) in 3/6 animals at

the end of the observation period; there was no difference between "with

rinsing" and "without rinsing"

INDIVUDUAL SCORES, with rinsing (1, 24, 48, 72h, 8d/animal) 

-Cornea: 0, 1, 0, 1, 1, 0; 0 (all further timepoints)

- Iris : 1, 0, 0, 0, 0, 0; 0 (all further timepoints)

- Conjunctivae (redness): 3, 2, 2, 2, 2, 2; 

 1, 0, 1, 0, 1, 1; 

 1, 0, 1, 0, 1, 1;

 1, 0, 1, 0, 0, 1;

 1, 0, 2, 0, 0, 1;

- Conjunctivae (chemosis): 2, 2, 2, 1, 3, 1;

 0, 2, 1, 0, 1, 1;

 0, 2, 1, 0, 1, 1;

 1, 1, 1, 0, 1, 1;

 1, 0, 2, 0, 0, 1;

INDIVUDUAL SCORES, without rinsing (1, 24, 48, 72h, 8d/animal) 

-Cornea: 0 (all timepoints evaluated)

- Iris : 1, 0, 0, 0, 0, 0; 0 (all further timepoints)

- Conjunctivae (redness): 2, 2, 2, 2, 3, 2; 

 2, 0, 1, 0, 1, 1; 

 1, 0, 1, 0, 1, 1;

 0, 0, 1, 0, 0, 1;

 0, 0, 2, 0, 0, 1;

- Conjunctivae (chemosis): 2, 2, 2, 1, 3, 1;

 1, 2, 1, 0, 1, 1;

 1, 2, 1, 0, 1, 1;

 0, 1, 1, 0, 0, 1;

 0, 1, 2, 0, 0, 1;

Test condition : TEST ANIMALS:

strain: New Zealand Wight

sex: male

ADMINISTRATION/EXPOSURE:

the test material was applied into the conjunctival sac of the lower lid of

both eyes; the lids were gently held together for one second. The right eye

was flushed 30 s after the application (physiol. saline solution; 3 min.) the

left was not flushed

EXAMINATION:

The findings were determined 1 (only for the flushed eyes), 24, 48 and 72

hours and 8d after application. 

EVALUATION:

The scoring system of Draize was applied to calculate the irritation index;

the 24, 48 and 72 hours values are the basis for the irritation index; the

88
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DATE: 09.11.2006

levels of damage to cornea (0-80), iris (0-10) and conjunctiva (0-20),

together 0-110, are added for all six animals after 24, 48 and 72 hours. the

total is divided by 18, and yields the level of primary irritation to the eye.

Reliability : (2) valid with restrictions

The text of the summary and the individual scores are contradictory, the

reasons why the effects on the conjunctivae at the end of the observation

period have no biological relevance are not given

Flag : Critical study for SIDS endpoint

20.11.2004 (10)

Species : rabbit

Concentration : undiluted

Dose : 100 other: ul

Exposure time :

Comment : other: rinsed after 30 sec/not rinsed

Number of animals : 6

Vehicle :

Result : irritating

Classification :

Method : OECD Guide-line 405 "Acute Eye Irritation/Corrosion"

Year : 1981

GLP : no

Test substance : other TS: 4,4 ́-methylenedicyclohexyl diisocyanate solid sample, no data

on purity

Result : A primary irritation value of 0.4 was calculated for the flushed eyes (0 - 10

= not irritating); a primary irritation value of 6,3 was calculated for the

unflushed eyes (0 - 10 = not irritating); the slight irritation of the conjunctiva

(score 1-2 for redness and chemosis) has almost subsided after 24 hours

with rinsing, and after 72 hours without rinsing; total recovery was

documented after 72 hours (with rinsing) and 8 days (without rinsing);

corneal opacity was restricted to 3/6 (with rinsing) and 2/6 (without rinsing)

animals, respectivily and it was reversible within 24 (with rinsing) and 72

hours (without rinsing), respectivily.

INDIVUDUAL SCORES, with rinsing (1, 24, 48, 72h, 8d/animal) 

-Cornea: 1, 1, 0, 0, 0, 1; 0 (all further timepoints)

- Iris : 0 (all timepoints)

- Conjunctivae (redness): 2, 2, 2, 1, 1, 2; 

 0, 1, 1, 0, 0, 0; 

 0, 1, 1, 0, 0, 0;

 0, 0, 0, 0, 0, 0;

 0, 0, 0, 0, 0, 0;

- Conjunctivae (chemosis): 1, 1, 1, 1, 0, 1;

 0, 0, 0, 0, 0, 0;

 0, 0, 0, 0, 0, 0;

 0, 0, 0, 0, 0, 0;

 0, 0, 0, 0, 0, 0;

INDIVUDUAL SCORES, without rinsing (1, 24, 48, 72h, 8d/animal) 

-Cornea: 1 h was not evaluated

 4, 0, 0, 0, 0, 1

 1, 0, 0, 0, 0, 0

 0, 0, 0, 0, 0, 0 

 0, 0, 0, 0, 0, 0

- Iris : 0 (all timepoints)

- Conjunctivae (redness): 2, 2, 2, 1, 2, 2; 

 2, 1, 1, 1, 2, 2; 

 2, 1, 1, 1, 1, 2;

 2, 0, 0, 1, 0, 0;

 0, 0, 0, 0, 0, 0;

- Conjunctivae (chemosis): 2, 1, 2, 2, 1, 2;

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 2, 0, 0, 0, 1, 1;

 2, 0, 0, 0, 1, 1;

 0, 0, 0, 0, 0, 0;

 0, 0, 0, 0, 0, 0;

Test condition : TEST ANIMALS:

strain: New Zealand Wight

sex: male

ADMINISTRATION/EXPOSURE:

the test material was applied into the conjunctival sac of the lower lid of

both eyes; the lids were gently held together for one second. The right eye

was flushed 30 s after the application (physiol. saline solution; 3 min.) the

left was not flushed

EXAMINATION:

The findings were determined 1 (only for the flushed eyes), 24, 48 and 72

hours and 8d after application. The 24, 48 and 72 hours values are the

basis for the irritation index; the levels of damage to cornea (0-80), iris (0-

10) and conjunctiva (0-20), together 0-110, are added for all six animals

after 24, 48 and 72 hours. the total is divided by 18, and yields the level of

primary irritation to the eye.

Reliability : (2) valid with restrictions

No data on purity of test substance

Flag : Critical study for SIDS endpoint

20.11.2004 (11)

Species : rabbit

Concentration : undiluted

Dose : 100 other: ul

Exposure time : 24 hour(s)

Comment : rinsed after (see exposure time)

Number of animals : 3

Vehicle :

Result :

Classification :

Method : other: see Test Condition 

Year : 1966

GLP : no

Test substance : other TS: 4,4 ́-methylenedicyclohexyl diisocyanate, no data on purity

Result : The compound was classed as a severe eye irritant; the average maximum

score was 63.3 out of a possible 110 in 24 hours; no reversibility within 168

hours

Copious discharge, partial eversion of the lids, moderately severe

erythema, and moderate corneal cloudiness produced an average score of

44.3 in one hour. The lids were closed ovenight and swelling extended for

a considerable distance around the eye. The iris was visible and continued

to react to light. Individual vessels of the conjunctivae were not easily

discernible. Gradual improvement followed

irrigation. The lida were still nearly closed after five days but corneal clarity

had improved markedly leading to the conclusion that eyesight would not

be permanently damaged.

Test condition : TEST ANIMALS:

strain: albino

sex: 1 male, 2 females

ADMINISTRATION/EXPOSURE:

The undiluted compound was placed in the conjunctival sac of the right

eye; the eyes were rinsed with isotonic saline solution after 24 hours

EXAMINATION:

observations were made at the end of 1 hour, 24, 48, 72, 120 and 168

hours; the data were scored according to the method of Draize.

Reliability : (4) not assignable

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No individual scores are reported

25.10.2004 (77)

Species : rabbit

Concentration : undiluted

Dose : 100 other: ul

Exposure time :

Comment : other: rinsed after 20 sec (6 rabbits), not rinsed (2 rabbits)

Number of animals :

Vehicle :

Result :

Classification :

Method : other: see Test Condition 

Year : 1979

GLP : no

Test substance : other TS: Hylene W (composition: 99.3%)

Remark : This test was done to determine the most effective eye wash for removal of

Isocyanic acid, Methylenebis-(4-cyclohexyl) ester from eyes

Result : The two rabbits, which served as positive controls (dosed with Hylene W

and not washed) showed mild conjunctivitis and irritation of the outer lids

(hair loss and occasional necrotic spots); no corneal or iritic effects occured

and the eyes were normal at 15 days except the hair loss on the outer lids

which was returning to normal at 28 days

Test condition : TEST ANIMALS:

strain: no data

sex: no data

ADMINISTRATION/EXPOSURE:

The undiluted compound was placed in the conjunctival sac of the right

eye; the treated eye of 2 animals was not washed; after 20 seconds the

treated eyes of the other rabbits were washed as follows:

- 2 eyes washed 1 minute with tape water

- 2 eyes washed 15 minutes with tape water

- 2 eyes washed 1 minute with 25% aqueous propylene glycol with 0.01%

thimerosal

EXAMINATION:

observations of the cornea, iris and conjunctiva were made with a hand-slit

lamp at 1 and 4 hours, 1, 2, 3, 7, 14 or 15, and 28 days

Reliability : (3) invalid

Unsuitable test system (for further explanation see "remark")

25.10.2004 (56)

5.3 SENSITIZATION

Type : other: Modified Guinea pig maximization test

Species : guinea pig

Number of animals : 20

Vehicle : other: paraffin oil

Result : not sensitizing

Classification :

Method : other: modified OECD TG 406

Year : 1984

GLP : no

Test substance : other TS: 4,4 ́-Methylenedicyclohexyl diisocyanate (liquid), mixed isomers,

no further data

Remark : In a pilot study with 4 animals the skin irritation was examined for the

challenge with 0.03, 0.1, 0.3% and 1% (24 hours, occlusive); the animals

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were treated with FCA and paraffin oil like the control animals

0.03%: 3 of 4 animals showed mild or moderate erythema; 

>= 0.1%: all animals showed mild up to pronounced signs of irritation which

were still evident after 72 hours.

Result : 1/20 treated animals died after the second induction, because none of the

remaining animals showed clinic signs the death seemed to be not

substance related.

1. challenge: 

0.01%: 0/19 (2/10 in the control group) with a positive reaction

0.03%: 0/19 (6/10 in control group) with a positive reaction

2. challenge:

0.01%: 0/19 (5/10 in the control group) with a positive reaction

0.03%: 1/19 (6/10 in control group) with a positive reaction

The reason why there were more positive responses in the control groups

with both concentrations is not entirely understood but local irritant effects

seemed to be involved.

Test condition : Animals are acclimatised to the laboratory conditions for approx. 1 week

prior to the test.

Before the test, animals are randomised and assigned to the treatment

groups; Number of animals: 20 test and 2 x 10 control guinea pigs have

been used; removal of hair is by shaving and chemical depilation

(challenge). The animals are weighed before the test commences and

every week during the study. All skin reactions and any unusual findings,

including systemic reactions were observed twice a day and recorded.

Induction: Intradermal Injections

Day 0 - treated group

Three pairs of intradermal injections of 0.1 ml volume are given in the

shoulder region which is shaved.

Injection 1: a 1:1 mixture (v/v) Freunds Complete Adjuvans (FCA)/water

Injection 2: the test substance in paraffin oil 

Injection 3: the test substance formulated in FCA

Day 0 - control groups

Three pairs of intradermal injections of 0.1 ml volume are given in the same

sites as in the treated animals.

Injection 1: a 1:1 mixture (v/v) FCA/water

Injection 2: paraffin oil

Injection 3: FCA

Induction: Intradermal injections

Day 7 - treated group

Three pairs of intradermal injections of 0.025 ml volume of the undiluted

test material are given in the same sites as in the induction. 

Day 7 - control groups

no treatment

Challenge: Topical Application

Day 21 - treated and first control group

A patch with the test substance is applied to the opposed flanks of the

animals. The patches are held in contact by an occlusive dressing for 6

hours.

Day 35 - treated and second control group

A patch with the test substance is applied to the opposed flanks of the

animals. The patches are held in contact by an occlusive dressing for 6

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hours.

Observations - treated and control groups

After removing the patch (1 hour before the first evaluation) the challenge

area is cleaned and

depilated to facilitate the evaluation of the skin reaction;

- approximately 8 hours from the start of the challenge

application the skin reaction is observed and recorded according to

MAGNUSSON AND KLIGMAN GRADING SCALE FOR THE

EVALUATION OF CHALLENGE PATCH TEST REACTIONS

0 = no visible change

1 = discrete or patchy erythema

2 = moderate and confluent erythema

3 = intense erythema and swelling

- approximately 16 hours after this observation a second observation (24

hours), a third (48 hours) and fourth (72 hours) is made and once again

recorded.

Skin reactions which are observed at two observation times are evaluated

"positive". An animal is evaluated as sensitized if the treated animal

showes a positive response without any evidence of irritation.

1st: Induction (day 0): 10% intradermal

2nd: Induction (day 7): undiluted intradermal

3rd: Challenge (day 21 and 35): 0.01 and 0.03% occlusive (6 hours);

Reliability : (2) valid with restrictions

Restrictions: no standard protocol; no range finding for the induction;

slightly irritating concentration for the challenge

Flag : Critical study for SIDS endpoint

22.12.2005 (12)

Type : Guinea pig maximization test

Species : guinea pig

Number of animals : 20

Vehicle : other: paraffin oil

Result : not sensitizing

Classification :

Method : other: similar to OECD TG 406

Year : 1985

GLP : yes

Test substance : other TS: 4,4 ́-Methylenedicyclohexyl diisocyanate (liquid), mixed isomers,

no further data

Remark : In a pilot study for the challenge the skin irritation was examined with 4

animals with 0.01, 0.03, 0.1 and 0.3% (24 hours, occlusive); the animals

were treated with FCA and paraffin oil like the control animals; only one

animal showed skin irritation with all applied concentration and at every

examination time (48 and 72 hours after application)

Result : 0.001%: 1/20 (1/10 in the control group) with a positive reaction

0.01%: 1/20 (5/10 in control group) with a positive reaction

The reason why half of the control animals showed a positive reaction

towards 0.01% is not entirely understood but local irritant effects seemed to

be involved.

Test condition : Animals are acclimatised to the laboratory conditions for approx. 1 week

prior to the test.

Before the test, animals are randomised and assigned to the treatment

groups; Number of animals: 20 test and 10 control guinea pigs have been

used; removal of hair is by shaving and chemical depilation (challenge).

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The animals are weighed before the test commences and every week

during the study. All skin reactions and any unusual findings, including

systemic reactions were observed twice a day and recorded.

Induction: Intradermal Injections

Day 0 - treated group

Three pairs of intradermal injections of 0.1 ml volume are given in the

shoulder region which is shaved.

Injection 1: a 1:1 mixture (v/v) Freunds Complete Adjuvans (FCA)/water

Injection 2: the test substance in paraffin oil 

Injection 3: the test substance formulated in paraffin oil/FCA (1:1)

Day 0 - control group

Three pairs of intradermal injections of 0.1 ml volume are given in the same

sites as in thetreated animals.

Injection 1: a 1:1 mixture (v/v) FCA/water

Injection 2: paraffin oil

Injection 3: paraffin oil in a 1:1 mixture (v/v) FCA/water

Induction: Topical Application

Day 7 - treated group

A adhesive tape (2.5 x 2.5 cm) is fully-loaded with test

substance in paraffin oil and applied to the test area and held in contact by

an occlusive dressing for 48 hours. 

Day 7 - control group

Paraffin oil only is applied in a similar manner to the

test area and held in contact by an occlusive dressing for 48 hours.

Challenge: Topical Application

Day 21 - treated and control groups

A patch with the test substance is applied to the opposed flanks of the

animals. The patches are held in contact by an occlusive dressing for 24

hours.

Observations - treated and control groups

After removing the patch the challenge area is cleaned and

depilated to facilitate the evaluation of the skin reaction;

- approximately 48 hours from the start of the challenge

application the skin reaction is observed and recorded according to

MAGNUSSON AND KLIGMAN GRADING SCALE FOR THE

EVALUATION OF CHALLENGE PATCH TEST REACTIONS

0 = no visible change

1 = discrete or patchy erythema

2 = moderate and confluent erythema

3 = intense erythema and swelling

- approximately 24 hours after this observation a second observation (72

hours) and third (96 hours) is made

and once again recorded.

An animal is evaluated as sensitized if the treated animal showes a skin

reaction graded >=1 without any evidence of irritation at 2 observation

times.

CONCENTRATION: 

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1st: Induction (day 0): 1% intradermal

2nd: Induction (day 7): 10% topical (occlusive; 48 hours)

3rd: Challenge (day 21): 0.001 and 0.01% topical (occlusive ; 24 hours)

Reliability : (2) valid with restrictions

No range finding for the induction. Slightly irritating test concentrations for

the challenge

Flag : Critical study for SIDS endpoint

22.12.2005 (13)

Type : Buehler Test

Species : guinea pig

Concentration : 1

st: Induction 2 %

2

nd: Challenge .5 % 

3

rd: 

Number of animals : 20

Vehicle : petrolatum

Result : sensitizing

Classification :

Method : Directive 96/54/EC, B.6 

Year : 1998

GLP : no data

Test substance : other TS: Desmodur W, purity: > 99.5%

Result : 19/20 showed a positive reaction

Test condition : Strain: Dunkin-Hartley

Sex: female

Dose: 0.5 ml for induction and challenge

Histopathological examination was carried out to clarify doubtful reactions,

and the results were interpreted as positive only if they were confirmed as

sensitization reactions of experimental eczema; the sensitivity and

realiability of the test were assessed by the use of reference substance

(neomycin sulfate)

Reliability : (2) valid with restrictions

Limited documentation

Flag : Critical study for SIDS endpoint

05.11.2004 (100)

Type : Buehler Test

Species : guinea pig

Number of animals : 15

Vehicle : other: olive oil and anhydrous acetone (1 : 1)

Result :

Classification :

Method : other: see Test Condition 

Year : 1984

GLP : yes

Test substance : other TS: 4,4 ́-Methylenedicyclohexyl diisocyanate, no data on purity

Remark : An irritation range-finding study was performed in order to select a vehicle

and doses for the induction and challenge applications.

Six animals were treated topically with 1.0, 0.3, 0.1, 0.03, 0.01 and 0.003

Molar of the test material in 100% olive oil or in a 1 : 1 mixture of olive oil

and anhydrous acetone under occlusive conditions. The patches were left

in place for 6 hours. Observations for irritation were made 24 and 48 hours

after application and again at day 4, 5 or 6.

Result : Author ́s conclusion: Under conditions of this study 4,4

 ́-methylenedicyclohexyl diisocyanate exhibited the potential to produce

dermal sensitization in guinea pigs.

Concentrations selected for induction were only non-irritating for all low95
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DATE: 09.11.2006

and mid-dose animals 24 hours after the first induction exposure;

subsequently almost all animals developed skin reactions; for the high

dose group the induction concentration was irritating upon initial

administration; responses generally increased in incidence and severity

after subsequent induction exposures; this type of response to repeated

exposures may represent a cumulative irritant effect and/or may be

indicative of sensitization.

With the high challenge concentration (60 milliMolar = mid-dose for

induction) 9//15 animals of the low dose for induction; 13/15 animals of the

mid-dose for induction and 15/15 animals of the high dose for induction

showed scores greater than 0. 

With the mid-high challenge concentration (20 milliMolar = low-dose for

induction) 1/15 animals of the low dose for induction; 5/15 animals of the

mid-dose for induction and 5/15 animals of the high dose for induction

showed scores greater than 0.

With the other challenge concentrations (0.06-6 milliMolar) no skin

reactions were observed in any animal of dose groups for induction.

2/6 irritation controls ad high dose had minimal scrores at 48 hours only.

cross-reactivity to structurally related materials (e.g. TDI, MDI, IPDI) was

less pronounced.

Test condition : Number of animals: 15/concentration; 6 control animals (did not receive

induction exposures)

Dose levels

induction exposure: 20, 60, 200 milliMolar

challenge exposure: 60, 20, 6, 0.6, 0.06 milliMolar/dose level

Induction: Topical application

Treated group:

One flank is cleared of hair (closely-clipped). The test material was

adiministered in a volume of 50 microliters beneath an adhesive-backed

gauze patch. The test patch was covered by ovelapping, impermeable

plastic and firmly secured by an elastic adhesive bandage wound around

the torso of the animal. The patch was held in contact with the skin for 6

hours after which it was removed . This was repeated at the same site

once weekly for 3 weeks, for a total of 3 applications.

control group: not used

Challenge

Treated groups:

Fourteen days after the last induction exposure the untreated flank of

treated animals is cleared of hair (closely-clipped). Five different

concentrations (25 microliters) were administered as described for the

induction. The patch was held in contact for 6 hours. In order to

differentiate possible dermal reactions produced by irritation from those

produced by sensitization, 6 additional animals (= control group) were

subjected to the same challenge procedure

Cross-Challenge

Single concentrations of 4 different materials were applied to the high dose

test animals upon recovery from challenge (7 days after challenge). Crosschallenge control animals were also treated with these materials and

concentrations.

Observations - treated and control groups

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Induction sites: prior to dosing and approximately 24 hours after each

induction application

Challenge sites: prior to dosing and approximately 24 and 48 hours after

challenge application

GRADING SCALE FOR THE EVALUATION OF CHALLENGE PATCH

TEST REACTIONS

0 = no visible change

1 = discrete or patchy erythema

2 = moderate and confluent erythema

3 = intense erythema and swelling

Reliability : (2) valid with restrictions

Only 15 animals/dose group, no control animals during induction exposure;

pronounced skin reaction during induction exposure, slightly irritating test

concentrations for the challenge

Flag : Critical study for SIDS endpoint

22.12.2005 (2)

Type : Mouse ear swelling test

Species : mouse

Number of animals :

Vehicle : other: acetone

Result : sensitizing

Classification :

Method : other: see Test Condition 

Year : 1987

GLP : no data

Test substance : other TS: 4,4 ́-Methylenedicyclohexyl diisocyanate, purity > 99.3%

Result : The dose response curve has a nearly vertical direction (single data were

not reported); this suggests that this compound may effect threshold

response rather than a dose-dependent one; the steep dose-response

curve suggested a threshold-type response occuring at 0.24 mg/kg; 

Crossreaction was observed to HDI and MDI

Test condition : NUMBER OF ANIMALS: groups 4 - 5 animals were used per dose with

many replicate determinations (no further data).

Mice were sensitized and challenged using the method described by

Stadler and Karol (Toxicol. Appl. Pharamacol. 78, 445-450, 1985) adapted

from that of Asherson and Ptak (Immunology 15, 405-410, 1968). 100 uI

acetone containing the specified amount of diisocyanate (no further

information available) was applied to the shaved and depilated abdomen of

the test animals. After 4 days the mice were challenged on the right ear

with acetone and on the left ear with acetone containing a nonirritating

dose isocyanate.Challenge doses were determined in separate

experiments in which groups of mice were administered 40, 100, 200, 400

ug isocyanate to the ear and measurements of ear thickness were taken at

24 h. A dose below that which caused an increase in ear thickness was

selected. Based on these tests, 40 ug 4,4 ́-methylenedicyclohexyl

diisocyanate were used for challenge.

Cross-reactivity studies were performed with diphenylmethane-4,4

 ́-diisocyanate (MDI), toluene diisocyanate (TDI) and hexamethylene

diisocyanate (HDI); the dose for sensitization was 0.75 mg 4,4

 ́-methylenedicyclohexyl diisocyanat/kg

Reliability : (2) valid with restrictions

Limited documentation

Flag : Critical study for SIDS endpoint

22.12.2005 (91)

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Type : Mouse local lymphnode assay

Species : mouse

Number of animals :

Vehicle :

Result :

Classification :

Method : other: an alternative endpoint (production of interleukin 6) was measured

(in vivo and in vitro experiments) 

Year :

GLP : no data

Test substance : other TS: 4,4 ́-Methylenedicyclohexyl diisocyanate, no data on purity

Remark : The objective of the studies published in the cited papers was to evaluate

the potential of a molecular (IL-6 production), rather than a cellular

(lymphocyte proliferation), endpoint for determing the extent of lymph node

activation induced by topical exposure to a chemical allergen; for this

special purpose the experiments were done with chemicals known to cause

contact sensitization

Result : 3 days after initiation of exposure the test material

induced at all lymph node cells (LNC) concentrations

vigorous proliferative response and significant levels of

IL-6 production

Reliability : (2) valid with restrictions

Limited documentation

22.12.2005 (43) (63) (65)

Type : Mouse local lymphnode assay

Species : mouse

Number of animals :

Vehicle : other: acetone : olive oil (4 : 1)

Result :

Classification :

Method : other: see Test Condition 

Year : 1992

GLP : no data

Test substance : other TS: 4,4 ́-Methylenedicyclohexyl diisocyanate, no data on purity

Remark : The objective of the studies published in the cited papers was to evaluate

the potential of a molecular (IL-6 production), rather than a cellular

(lymphocyte proliferation), endpoint for determing the extent of lymph node

activation induced by topical exposure to a chemical allergen; for this

special purpose the experiments were done with chemicals known to cause

contact sensitization

Result : While a lymphocyte proliferative response in lymph nodes draining was

observed, the test material did not induce a change in serum IgE

concentration. With regard to the author ́s opinion this result is consistent

with the differential immune response for contact and respiratory sensitizer.

The test material appears not to cause respiratory allergy but causes

contact sensitization.

Test condition : A combination of local lymph node assay (Groups of mice (n = 4) received

25 ul of various concentrations (0.1 - 5%) of the test material or an equal

volume of vehicle alone on the dorsum of both ears. Three days later all

mice received [3H]methylthymidine iv via the tail vein. Mice were killed 5 hr

later and draining auricular lymph nodes isolated and pooled for each

experimental group.) and measurement of serum IgE concentration in mice

(n= 10) which recieved the test material (50 ul, 2 or 1%) on each shaved

flank and seven days later the same test material (25 ul of a 1:1 dilution)

was applied to the dorsum of both ears.

Reliability : (2) valid with restrictions

Limited documentation

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Flag : Critical study for SIDS endpoint

22.12.2005 (42) (44)

Type : other

Species : other: mouse and guinea pig

Number of animals :

Vehicle : other: methylethyl ketone

Result :

Classification :

Method : other: See Test Condition 

Year : 1985

GLP : no data

Test substance : other TS: Desmodur W, no data on purity

Result : Application of high doses of each chemical resulted in extensive erythema

and a large proportion of animals became sensitzed. Lower doses

produced less sensitivity. In mice, as well as in guinea pigs, a doseresponse relationship was apparent between the sensitizing dose and both

severity of response and number of animals responding. For mice,

comparison of the dose of chemical required to sensitize 50% of the

animals (SD5O) yielded 0.40 mg/kg for PiCl and approximately 0.20 mg/kg

for 4,4 ́-Methylenedicyclohexyl diisocyanate (using probit analysis).

Test condition : The study was undertaken to determine if the dose-response relationship

could be used to assess the sensitizing potencies. Picryl chloride (PiCl)

was selected because the extensive literature describing its ability to cause

delayed dermal sensitivity.

Groups (4-8) of BALB/cBy mice and English smooth-haired guinea pigs (8)

were exposed to 4,4 ́-Methylenedicyclohexyl diisocyanate or PiCl by topical

exposure. Mice were challenged 5 days later using an ear swelling assay

(20 ul 0.5% PiCl, 0.1% 4,4 ́-Methylenedicyclohexyl diisocyanate) and the

thickness of each ear was measured 6, 24 and 48 hours postchallenge.

Guinea pigs were challenged 7 days later by patch testing (25 ul of 0.5%

PiCl or 0.1% 4,4 ́-Methylenedicyclohexyl diisocyanate) and responses

graded at 1, 2, 4, 6, 8,24 and 48 hr postchallenge.

Reliability : (2) valid with restrictions

Limited documentation

Flag : Critical study for SIDS endpoint

09.11.2006 (87)

Type : other

Species : guinea pig

Number of animals :

Vehicle :

Result :

Classification :

Method : other: see Test Condition 

Year : 1982

GLP : no data

Test substance : other TS: 4,4 ́-Methylenedicyclohexyl diisocyanate, purity: 99,3%

Remark : The study utilize a recently developed animal model (Karol et al., Toxicol.

Appl. Pharmacol. 53, 260-270 (1980) and 58, 221-230 (1981)) to evaluate

4,4 ́-methylenedicyclohexyl diisocyanate as a sensitizing agent and to

compare its respiratory and dermal sensitizing abilities with that of TDI.

Result : antibody response: 

with the double-diffusion assay, no antibodies were detected in sera tested

of any HMDI treated animal; few sera demonstrated antibodies when

applying the more sensitive passive cutaneous anaphylaxis technique, but

antibody titers were extremely low.

cutaneous reactions: 

99
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 - contact sensitivity was observed in the animals exposed by topical

application (12/12) and toepad inoculation

 - dermal sensitivity was observed in the animals exposed by topical

application (9/12) and i.p. injection (3/4)

- pulmonary sensitivity was only elicited with HMDI in acetone in 2/11

animals which have been sensitized with toepad inoculation of test material

in Freund ́s complete adjuvant; challenge with HMDI-GSA did not produce

any pulmonary response in these animals. No pulmonary sensitivity using

HMDI-GSA was detected in any of 12 guinea pigs sensitized by topical

exposure.

Test condition : Guinea pigs were exposed by topical application, intradermal and

intraperitoneal injection, as well as toepad inoculation of test material in

Freund ́s complete adjuvant; subsequent the animals were examined for

antibody body response (sera taken on days 15 and 22), contact sensitivity

(0,1% test material onto clean depilated dorsal area), dermal sensitivity

(intradermal injection of 0.1% HMDI-GSA) and pulmonary sensitivity

(bronchial provocation challenge with 0.1% HMDI in acetone and HMDI

-GSA)

Reliability : (2) valid with restrictions

Limited documentation

Flag : Critical study for SIDS endpoint

22.12.2005 (67)

Type : other

Species : other: mouse and guinea pig

Number of animals :

Vehicle : other: acetone

Result :

Classification :

Method : other: see Test Condition 

Year : 1984

GLP : no data

Test substance : other TS: Desmodur W, no data on purity

Result : Guinea pig: skin sensitivity following inhalation of

> 3 ug/l, no sensitization after 1,25 ug/l; 

mice: contact sensitivity was detected following inhalation

of > 17 ug/l, no reaction after < 7 ug/l; 

dermal contact of the head, as would occur during inhalation exposures,

also resulted in contact sensitization

Test condition : INDUCTION: 

guinea pig: inhalation for 2h/day on 3 consecutive days; head only

exposure to an aerosol (1, 3, 17, 32, 44, 53 mg/m3); 4

animals/concentration

mice: exposure was similiar to that described for guinea pigs, however

mice were expoed nose onyl exposed

mice: direct application to the noses of mice to cover an area comparable

to that which extended into the "nose-only" inhalation chamber; the

application was performed over a period of 2h on 3 consecutive days

CHALLENGE:

7 days following the initial inhalation exposure guinea pigs were challenged

by topical application (25 ul, 0.1% = nonirritating concentration) onto the

flank area and all mice (inhalation and dermal application) by application

(20 ul, 0.1% = nonirritating concentration) to each side of the right ear (ear

swelling test)

Reliability : (2) valid with restrictions

Limited documentation

Flag : Critical study for SIDS endpoint

14.01.2005 (86)

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Type : other: lung sensitization following intradermal induction

Species : guinea pig

Number of animals : 8

Vehicle :

Result :

Classification :

Method : other: see Test Condition 

Year : 1995

GLP : yes

Test substance : other TS: Desmodur W; purity: > 99.2 %

Result : Following induction, slight skin reactions at the injection sites occurred.

During or following test material-challenges, the incidence of immediateonset respiratory reactions was roughly the same in vehicle controls and

test substance-induced animals. No deaths or anaphylactic reactions were

observed during challenge, and no clinical signs or specific abnormalities

were observed at necropsy. The histopathological evaluation of lungs

revealed a marked influx of eosinophils in test material-sensitized guineapigs, a characteristic feature of asthma and airway hypersensitivity.

The study provides evidence that the testsubtance is weak respiratory

sensitizer in guinea pigs.

Test condition : ADMINISTRATION:

Groups of eight female guinea-pigs were intradermally induced once on

day 0 (injection volume: 100 ul/, 0.13 % solution in olive oil). Eight female

controls received vehicle alone under otherwise identical conditions.

Following a recovery period of approximately four weeks (starting on day

28) a test material-hapten challenge (mean concentration: 68 ± 3.6 mg/m3

air) was performed (challenge duration: 30 min). The technical exposure

criteria specified in OECD TG 403 were fulfilled insofar as these are

applicable to this study. The aerosolized test material proved to be of

adequate respirability.

EXAMINATIONS:

During and after challenge exposures with the hapten, immediate-onset

respiratory reactions were evaluated by measurement of respiratory rate,

tidal volume, respiratory minute volume, inspiratory and expiratory times,

and peak expiratory flow rate. Additional parameters were derived

mathematically. During sacrifice the trachea, lung, and lung associated

lymph nodes were fixed and subjected to histological evaluation.

Reliability : (1) valid without restriction

Flag : Critical study for SIDS endpoint

14.01.2005 (19)

Type : Patch-Test

Species : human

Number of animals :

Vehicle : petrolatum

Result :

Classification :

Method : other: no further data 

Year : 1976

GLP : no data

Test substance : other TS: Prepolymers consisting of 4,4 ́-methylenedicyclohexyl

diisocyanate (no further infomation available)

Result : 2/2 contact dermatitis patients showed a positive reaction in a patch test

with prepolymers consisting of 4,4 ́methylenedicyclohexyl diisocyanate

Test condition : 8/12 employees of a small polyurethane moulding plant who worked as

plastic molders developed contact dermatitis; the case history of 3 patients

is described in details; patch testing was performed with 2 of these 3

101
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patients with nonirritating concentrations (1%) and 4 healthy volunteers

served as control

Reliability : (2) valid with restrictions

Limited documentation

Flag : Critical study for SIDS endpoint

22.12.2005 (57)

Type : Patch-Test

Species : human

Number of animals :

Vehicle : other: toluene

Result :

Classification :

Method : other: no further data 

Year : 1980

GLP : no data

Test substance : other TS: Hylene W, no data on purity

Result : A case report about a student with contact sensitivity developed during a

project on manufacture of polyurethane foam; the student showed a

positive reaction when patch tested with 1% Hylene W; control patch tests

were performed on a member of staff who showed no response

Reliability : (2) valid with restrictions

Limited documentation

Flag : Critical study for SIDS endpoint

15.11.2004 (70)

Type : Patch-Test

Species : human

Number of animals :

Vehicle : petrolatum

Result :

Classification :

Method : other: no further data 

Year : 1977

GLP : no data

Test substance : other TS: 4,4 ́-Methylenedicyclohexyl diisocyanate, no data on purity

Result : A case report about a chemical engineer who began investigative work with

various polyester and isocyanates sufferd from itchy polymorphic

dermatitis; he was patch tested with the substances of the international

standard tray and with 32 substances he has used in his research; the only

substance to which he clearly reacted was 4,4 ́diisocyanatodicyclohexyl

methane (1%).

Reliability : (2) valid with restrictions

Limited documentation

Flag : Critical study for SIDS endpoint

22.12.2005 (73)

Type : Patch-Test

Species : human

Number of animals :

Vehicle : petrolatum

Result :

Classification :

Method : other: no further data 

Year : 1997

GLP : no data

Test substance : other TS: 4,4 ́-Methylenedicyclohexyl diisocyanate, no data on purity

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Result : A case report about a textile worker with pruritic, papulovesicular eruption

on the dorsum of her hands, forearms, axillae, sternum and anterior neck.

Patch testing to work related chemicals revealed strong positive reactions

to 4,4 ́-methylenedicyclohexyl diisocyanate (0.5, 0.1 and 0.05%) and

triethylenetetramine.

Reliability : (2) valid with restrictions

Limited documentation

Flag : Critical study for SIDS endpoint

22.12.2005 (90)

Type : Patch-Test

Species : human

Number of animals :

Vehicle : petrolatum

Result :

Classification :

Method : other: no further data 

Year :

GLP : no data

Test substance : other TS: 4,4 ́-Methylenedicyclohexyl diisocyanate, no data on purity

Result : In a factory where 4,4 ́-methylenedicyclohexyl diisocynate was used to

form a surface-coating polyurethane 7 females operatives suffered from

contact dermatitis, 2/7showed a positive reaction in the patch with 4,4

 ́-methylenedicyclohexyl diisocyanate (1%); no reaction was observed for

the 50 control patients.

Reliability : (2) valid with restrictions

Limited documentation

Flag : Critical study for SIDS endpoint

22.12.2005 (96) (97)

Type : Patch-Test

Species : human

Number of animals :

Vehicle : petrolatum

Result :

Classification :

Method : other: no further data 

Year : 1982

GLP :

Test substance : other TS: 4,4 ́-Methylenedicyclohexyl diisocyanate, no data on purity

Result : A woman woman who began working with 4,4 ́-methylenedicyclohexyl

diisocyanate and a poly-type catalyst suffered from pruritic, erythematous

dermatitis after one week. Patch testing were performed with the

diisocyanate (1%), the polyether glycol blend, a previously used epoxy

resin and hardener and to the standard American Academy of Dermatology

tray of patch test substances; there was a reaction (3+) to 4,4

 ́-methylenedicyclohexyl diisocyanate; all other patch tests were negative

Reliability : (2) valid with restrictions

Limited documentation

Flag : Critical study for SIDS endpoint

22.12.2005 (64)

Type : Patch-Test

Species : human

Number of animals :

Vehicle : petrolatum

Result :

Classification :

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Method : other: see Test Condition 

Year : 2003

GLP : no data

Test substance : other TS: 4,4 ́-Methylenedicyclohexyl diisocyanate, no data on purity

Result : 13/17 contact dermatitis patients working at a factory manufacturing

medical equipment showed a positive reaction with 4,4

 ́-methylenedicyclohexyl diisocyanate (0.1 and 1%) and the isocyanate

glue, while none reacted to the other

constituent, TDI. 5 patients showed simultaneous reactions to 4,4

 ́-methylenedicyclohexyl diisocyanate and 4,4 ́-methylenebis

(cyclohexylamine). In several cases, the patients also showed multiple

reactions to 1 or more

preparations of the isocyanate series. 9 patients also reacted to 1.6-

hexamethylenediisocyanate (HDI), 4 to isophoronediisocyanate (IPDI), 1 to

isophorone diamine (IPDA) and 5 to MDA.

5/12 showed positive reaction with 0.01% 4,4 ́-methylenedicyclohexyl

diisocyanate. 

Test condition : Patch testing was performed using the Finn Chamber on Scanpor tape

technique lixed with Scanpor or Medipore tape. Patch tests were removed

after 2 days by the patient and read after 1 day, according to International

Contact Dermatitis Research Group criteria. In 7 cases, a 2nd reading was

done 7 days after the initial application of

patches.

Reliability : (2) valid with restrictions

Limited documentation

Flag : Critical study for SIDS endpoint

22.12.2005 (59)

Type : Guinea pig maximization test

Species : guinea pig

Number of animals : 20

Vehicle : other: olive oil and acetone/olive oil (2. challenge)

Result :

Classification :

Method : OECD Guide-line 406 "Skin Sensitization"

Year : 1993

GLP : no

Test substance : other TS: Desmodur W, purtiy: 99.2 %

Remark : A pilot study for the induction (intradermal: 1, 2, 2.5 and 5%; topical: 12, 25,

50 and 100%) was performed.

In a pilot study with 5 animals the skin irritation was examined for the

challenge with 0.25, 0.5, 1 and 3% (24 hours, occlusive); the animals were

treated with FCA and olive oil like the control animals;

skin effects were noticed in

2/5 animals >= 0.25%

3/5 animals >= 0.5%

4/5 animals with 1%

Result : Under these testing conditions it can not be excluded that

the testsubstance has a sensitizing potential

1. challenge: 

0.25%: 20/20 (10/10 in the control group) with a positive reaction

1%: 20/20 (7/10 in control group) with a positive reaction

2. challenge:

0.25%: 17/20 (8/10 in the control group) with a positive reaction

1%: 20/20 (9/10 in control group) with a positive reaction

Test condition : CONCENTRATION:

1st: Induction (day 0): 5% intradermal

2nd: Induction (day 7): 3% occlusive (48 hours)

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3rd: Challenges (day 21 and 35): 0.25 and 1% semiocclusive (24 hours);

vehicle: acetone/olive oil (1:1)

Reliability : (3) invalid

Clearly irritating concentration for the two challenges; irritating vehicle

27.10.2004 (15)

Type : Intracutaneus test

Species : guinea pig

Number of animals : 10

Vehicle :

Result : sensitizing

Classification :

Method : other: see Test Condition 

Year : 1977

GLP : no

Test substance : other TS: Hylene W, no data on purity

Result : One animal died from noncompound related causes.

1. challenge (by error only 5 of the 9 test animals were treated):

positive response in 5/5 animals with 0.5% solution;

positive response in 2/5 with 0.1% solution; no response

with 0.05% and 0.01% solution

2. challenge:

positive response in 5/9 with 0.1% and 1/9 with 0.05% solution

Test condition : A series of four sacral intradermal injections was given, one each week

over a three week period, which consisted of 0.1 ml of a 1% solution of test

material in dimethyl phthalate; following a 2 weeks rest period, the test

animals were challenged by applying and lightly rubbing in, 0.05 ml of a

0.5%, 0.1%, 0.05% and 0.01% solution of test material in acetone on the

shaved intact shoulder skin. A group of previously unexposed animals

received similar applications at the time of challenge. After a two week rest

period the test animals were rechallenged by applying and lightly rubbing in

one drop of a 0.1% and 0.05% solution in acetone. A new group of ten

previously unexposed animals were treated in the same fashion.

Reliability : (3) invalid

Unsuitable test system

27.10.2004 (54)

Type : other

Species :

Number of animals :

Vehicle :

Result : sensitizing

Classification :

Method : other: mouse ear swelling test (published elsewhere and local lymph node

assay, unpublished) 

Year : 1994

GLP : no data

Test substance : other TS: 4,4 ́-Methylenedicyclohexyl diisocyanate, no data on purity

Remark : In this article the development and validation of the murine local lymph

node assay are described and comparisons with guinea pig predictive test

methods discussed. In addition we examine the advantages and limitations

of the method and consider new opportunities and applications of the

assay in the context of the toxicological evaluation of sensitizing potential.

Result : both test results are cited as positive in this review article

Reliability : (4) not assignable

Secondary literature

22.12.2005 (69)

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Type : other

Species : guinea pig

Number of animals : 6

Vehicle :

Result :

Classification :

Method : other: see Test Condition 

Year : 1974

GLP : no

Test substance : other TS: 4,4 ́-Methylenedicyclohexyl diisocyanate, no data on purity

Result : During sensitization period a small but statistically

significant increase in airway resistance; in the recovery

period animals returned to within baseline level after a short period of time;

after challenge exposure no increase in airway resistance

Test condition : Animals were exposed (whole body) to an average of 6.70 ug/l 4 hours/day

fo 5 days; 2 weeks after the last exposure the animals received a single

challenge exposure of 1.6 ug/l for 4 hours;

isocyanate aerosol was obtained by heating at 75-120 °C in an apparatus

and dry house-air ears passed through;

3 animals were sacrificed immediately after the challenge exposure and

another 3 were killed seven days later for pathological examination, blood

was collected from the heart at the time of the sacrifice in order to obtain

anti-isocyanate immune serum; lungs were fixed and prepared for

miscroscopic slides

Reliability : (3) invalid

Unsuitable test system

22.12.2005 (52)

Type : other

Species : mouse

Concentration : 1

st: 2 % 

2

nd: 

3

rd: 

Number of animals :

Vehicle :

Result :

Classification :

Method : other: see Test Condition 

Year : 2004

GLP : no data

Test substance : other TS: 4,4 ́-Methylenedicyclohexyl diisocyanate, no data on purity

Result : there were no change in total or differential cell counts at any time;

significant hyperresponsiveness at 2 weeks; these differences were greater

at 4 weeks

Test condition : BALB/c mice received 5 dermal exposure over a period of 2 weeks; mice

were then challenged with increasing doses of methacholine and

responsiveness was assessed using whole body plethysmorgraphy; half of

the group was killed and serum, bronchoalveolar lavage fluid and lymph

nodes were collected for total IgE, cell counts and cytokine profiling; the

remaining mice were exposed for additional 2 weeks and reassessed

Reliability : (4) not assignable

Abstract

22.12.2005 (83)

Type : other

Species : mouse

Number of animals :

Vehicle :

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Result :

Classification :

Method : other: see Test Condition 

Year : 2002

GLP : no data

Test substance : other TS: 4,4 ́-Methylenedicyclohexyl diisocyanate, no data on purity

Result : induction of cytokines which are characteristic of a Th2T cell response

Test condition : Previous studies have shown that RNA message levels for the Th2T cell

cytokines IL4, IL10 and IL 13 are elevated in response to respiratory

sensitizer trimellitic anhydride and these increases may be detected by

ribonuclease protection assay (RPA).

Female BALB/c mice were topically exposed to the test material and total

mRNA was isolated from draining lymph nodes 14 days post challenge.

Reliability : (4) not assignable

Abstract

22.12.2005 (80)

Type : other

Species : guinea pig

Number of animals : 6

Vehicle :

Result :

Classification :

Method : other: see Test Condititon 

Year : 1971

GLP : no

Test substance : other TS: Hylene W, no data on purity

Result : 1/6 elicited sensitization response, no cross-sensitization with TDI and MDI

(polymer)

Test condition : Animals were exposed to the aerosol mist (0.22 ppm x 4 hous x 3 days),

following a one-week rest period, the animals were challenged via the skin

route (0.5% and 0.1% Hylene W in 13% guinea pig fat in a 1:1 solution of

acetone and dioxane)

Reliability : (3) invalid

Unsuitable test system

29.10.2004 (48)

5.4 REPEATED DOSE TOXICITY

Type : Sub-acute

Species : rat

Sex : male/female

Strain : Wistar

Route of admin. : inhalation: aerosol

Exposure period : 5 days

Frequency of treatm. : 6 h/day on 5 consecutive days

Post exposure period : 2 days

Doses : 0, 1, 6, 36 mg/m3 (target concentration) - 1.7, 5.86, 34.18 mg/m3 (actual

concentration)

Control group : other: conditioned air

Method : other: pilot dose-range finding study according OECD Guide-line 412

Year : 2002

GLP : yes

Test substance : other TS: Desmodur W, purity 99.3%

Remark : pilot dose-range finding study (main study: Bayer MaterialScience AG;

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Report No. AT01057 (2004))

Result : Mortality: none

Rats exposed to 1 and 6 mg/m3 did not elaborate any test substanceinduced clinical signs, neurological effects, changes in rectal temperatures

or changes on body

weights. Rats exposed to 36 mg/m3 and above experienced a mild and

transient decrease in body weights and signs of respiratory tract irritation

(salivation, bradypnea, stridor).

At 36 mg/m3 the lung (m=12%;f=14%) and heart (m=17%; f=3%) weights

were significantly increased. 

Gross necropsy findings (less collapsed lungs with red foci and red

secretions in the nose) were observed only at this exposure level.

Test condition : TEST ORGANISMS

- Age: 2 month 

- Number of animals: 5/dose/sex

ADMINISTRATION / EXPOSURE

- Type of exposure: nose-only exposure

- Particle size: MMAD range: 0.947-1.02μm (geometric standard

deviation: approx. 2)

CLINICAL OBSERVATIONS AND FREQUENCY:

- Clinical signs: twice daily (exposure days)

- Mortality: twice daily

- Body weight: days 0, 4, 7

- Rectal Temperature: days 0 and 4

ORGANS EXAMINED AT NECROPSY (MACROSCOPIC AND

MICROSCOPIC): 

- Gross Pathology

- Organ Weights: Brain, Heart, Kidneys, Liver, Lungs,

 Spleen, 

- Microscopic: none

STATISTICAL METHODS: Dunnett Test, Adjusted Welch Test, KruskalWallis Test

Conclusion : Author concluded: Taking all findings into account 6 mg/m3 constitutes a

no-observed adverse effect-level.

Reliability : (2) valid with restrictions

A pilot dose-range finding study

Flag : Critical study for SIDS endpoint

14.01.2005 (33)

Type : Sub-acute

Species : rat

Sex : male/female

Strain : Wistar

Route of admin. : inhalation: aerosol

Exposure period : 4 weeks

Frequency of treatm. : 6 hours per day (5 days/week)

Post exposure period : none

Doses : 0, 1, 6, 36 mg/m3 (target concentration); 1.06, 6.02, 33.8 mg/m3 (actual

concentration)

Control group : other: conditioned air

NOAEL : = 1 mg/m3

Method : OECD Guide-line 412 "Repeated Dose Inhalation Toxicity: 28-day or 14-

day Study"

Year : 2003

GLP : yes

Test substance : other TS: Desmodur W, purity 99.3%

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Result : Mortality: none

Clinical signs:

Group 1 and 2 (controls and 1 mg/m3): 

all rats tolerated the exposures without any clinical signs.

Group 3 (6 mg/m3): 7/10 male and 7/10 female animals with signs after

exposure; e.g. nasal discharge (most rats recovered during the exposurefree weekends).

Group 4 (36 mg/m3): 

Bradypnea, labored breathing patterns, irregular breathing patterns, stridor,

tachypnea, nasal discharge, nostrils: red encrustations.

A gender-specific susceptibility could not be ascertained. Most signs

suggestive of respiratory tract irritation were observed from the second

exposure week onwards.

Nasal discharge and reddened nostrils were observed throughout the study

period.

Rectal temperature:

In comparison to the control group, there the body (rectal) temperatures of

rats of the 36 mg/m3 group were mildly, although significantly decreased

on days 0 (both sexes) and 21 (males).

Body weights:

no toxicologically consistent effect on body weights up to and including the

36 mg/m3 group.

1 mg/m3: 

no significant different body weights compared to control animals (except

an increase on day 14 in females)

6 mg/m3: 

significant increase on days 4, 11, 14, 18, 21, 25, 28 in females, 

36 mg/m3: 

no significant different body weights compared to control animals (except

an increase on day 11 in females)

Hematology and Clinical Pathology:

no effects considered to be of pathodiagnostic relevance

Ophthalmology: no changes

Gross Pathology:

Absolute Organ Weights:

1 mg/m3: 

male: no changes

female: elevated spleen and thymus weights

6 mg/m3:

male: no changes

female: elevated spleen and liver weights

36 mg/m3:

male: no changes

female: elevated lung weights (approx. 12%)

Relative Organ Weights (vs. body weights):

1 mg/m3: 

male: no changes

female: decreased brain and kidney weights

6 mg/m3:

male: no changes

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female: decreased brain weights

36 mg/m3:

male: elevated lung weights (approx. 12%)

female: elevated lung weights (approx. 12%) and decreased liver weights

Relative Organ Weights (vs. brain weights):

1 mg/m3: 

male: no changes

female: elevated spleen and thymus weights

6 mg/m3:

male: no changes

female: elevated spleen weights

36 mg/m3:

male: no changes

female: elevated lung weights (approx. 12%)

During necropsy, no findings were seen which have to be assessed as

treatment-related.

Histopathological findings:

NASAL CAVITY:

In the anterior level of the nasal cavity (nasal location 1) squamous

epithelial metaplasia occurred in all high concentration (36 mg/m3) males

and females, in most rats together with mucus and/or cells in lumen (10/10

males; 8/10 females), with inflammatory infiltrates (8/10 males, 7/10

females) and some males (3/10) in combination with focal epithelial

necrosis.In these animals, in the nasal locations 2 to 4 (posterior level)

epithelial changes were detectable in some rats (max. 2-4 animals per sex)

indicating beginning metaplasia.

In mid dose (6 mg/m3) animals epithelial changes were only seen in the

anterior level of the nasal cavity in some rats (3/10 males, 3/10 females).

In low dose (1 mg/m3) animals no epithelial changes were seen in the

nasal cavity.

PHARYNX:

In the pharynx, epithelial metaplasia occurred in almost all high

concentration (36 mg/m3) males (9/10) and females (9/10) and in only one

mid concentration male.

LARYNX

In the larynx, all test substance exposed animals showed epithelial

metaplasia (30/30 males and 30/30 females) together with increased

inflammatory infiltrates. Focal inflammatory infiltrates were also detectable

in control animals.

Focal inflammatory infiltrates:

controls:

10/10 males with grade 1; 9/10 females with grade 1

1 mg/m3: 

2/10 males with grade 1 and 8/10 males with grade 2;

5/10 females with grade 1 and 5/10 females with grade 2

6 mg/m3: 

10/10 males with grade 2; 10/10 females with grade 2

36 mg/m3: 

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10/10 males with grade 2; 10/10 females with grade 2

Epithelial metaplasia:

controls:

0/10 males and 0/10 females

1 mg/m3: 

10/10 males with grade 2

2/10 females with grade 1 and 8/10 females with grade 2

6 mg/m3: 

5/10 males with grade 3 and 5/10 males with grade 4

5/10 females with grade 3 and 5/10 females with grade 4

36 mg/m3: 

3/10 males with grade 3 and 7/10 males with grade 4

1/10 females with grade 3 and 9/10 females with grade 4

TRACHEA:

In the trachea, epithelial changes indicating beginning epithelial metaplasia

were seen in about half of the high concentration (36 mg/m3) males (6/10)

and females (5/10) and in each one low and mid concentration male,

respectively.

LUNG:

In the lungs, inflammatory lesions in the bronchiolo-alveolar region

occurred in the majority of high concentration males (8/10) and females

(9/10). These inflammatory lesions consisted of an increased cellularity in

the terminal bronchioles and alveolar ducts with more alveolar

macrophages and a focally increased septal thickening.

Furthermore, intraalveolar macrophages, mainly enlarged and with a foamy

cytoplasm, were obvious in almost all high concentration rats (10/10 males,

9/10 females) and in some animals from the other groups (6 mg/m3: 4/10

males, 3/10 females; 1 mg/m3: 2/10 in both sexes; control animals: 0/10

males, 1/10 females)).

Comparable to the epithelial changes in the upper airways, similar lesions

indicating beginning metaplasia occurred in the bronchi (36 mg/m3: 10/10

males, 9/10 females; 6 mg/m3: 5/10 males, 4/10 females; 1 mg/m3 and

control animals of both sexes: no changes), predominantly at the main

airway bifurcations.

In the other organs/tissues evaluated, no findings could be detected which

have to be assessed as treatment related. All the other findings were

known from controls of previous studies to be of spontaneous nature.

Test condition : TEST ORGANISMS

- Age: 2 month 

- Number of animals: 10/dose/sex

ADMINISTRATION / EXPOSURE

- Type of exposure: dynamic directed-flow nose-only exposure

- Doses: 

mean actual analytical concentrations of 1.057, 6.022, 33.83 mg/m3;

nominal concentration of 4.8, 19.8 and 118.9 mg/m3

- Particle size: MMAD range: 1.0-1.2μm (geometric standard deviation

approx. 2); highly respirable to rats 

CLINICAL OBSERVATIONS AND FREQUENCY:

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- Clinical signs: twice daily (exposure days)

- Mortality: twice daily

- Body weight: twice weekly

- Rectal Temperature: days 0 and 21

- Reflexes: days 3 and 21

- Ophthalmoscopic examination: prior the first exposure, towards the end

of the exposure period

CLINICAL PATHOLOGY at the end of study

- Haematology

- Biochemistry

- Urinalysis

ORGANS EXAMINED AT NECROPSY (MACROSCOPIC AND

MICROSCOPIC): 

- Gross Pathology:

Fixed organs: Adrenals, aorta, brain (cerebrum, cerebellum, ponslmedulla),

epididymides, esophagus, eyes, eyelids, extraorbital lachrymal glands,

femur, harderian glands, head (with nasal and paranasal cavities), heart,

intestine (duodenum, jejunum, ileum, cecum, colon, rectum and remaining

intestine), kidneys, larynx, liver, lymph nodes (mandibular, bronchial/hilus,

and mesenteric), lung, mamma, optical nerves, ovaries, oviducts,

pancreas, pharynx, pituitary, prostate, salivary glands, sciatic nerve,

seminal vesicles (incl. coagulating glands), skeletal muscle (thigh), skin

(mammary and muzzle), spinal cord (cervical, thoracic, lu,mbar), spleen,

sternum, stomach (forestomach and glandular stomach), testes, thymus,

thyroids (including parathyroid glands), tongue, trachea, ureter, urethra,

urinary bladder, uterus with uterine cervix, vagina, Zymbal’s glands and all

organs or tissues with macroscopic findings.

Organ Weights: Adrenals, brain, heart, kidneys, Liver, Lungs, Ovaries,

Spleen, Testes, Thymus

- Microscopic: From the respiratory tract (nasal cavity, pharynx, larynx,

trachea, lungs and lung associated lymph nodes) slides from all animals

were evaluated. From the other organs/tissues assigned for

histopathological

evaluation, slides were prepared from the first five animals of all groups

and evaluated from the control and the high concentration group. 

STATISTICAL METHODS: Dunnett Test, Adjusted Welch Test, KruskalWallis Test

Conclusion : The test substance was tolerated without any systemic adverse effects at

all exposure levels (1, 6, 36 mg/m3). At 36 mg/m3, evidence of respiratory

irritation existed which also occurred at 6 mg/m3 in borderline intensity.

With regard to histopathological changes, all changes observed were

related to portal-of-entry, local irritant effects (nasal passages, larynx,

airways and alveoli), i.e, changes that occurred at anatomical structures, to

some extent rat specific, favoring focal deposition of irritant particulates. No

changes of pathodiagnostic relevante occurred at 1 mg/m3, except the

laryngeal findings. The laryngeal squamous epithelial metaplasia is

considered to be a rather rat-specific response. In the rat, the layout of the

upper respiratory structures is tandem such that the air could travel in

nearly linear fashion from the nose to the bifurcation of the trachea. The

linear arrangement of the upper airways allows the larynx of rats to lie

close to the posterior edge of the oral and nasal cavities. In the condition,

the epiglottis lies against the soft palate. The apposition of the epiglottis to

the soft palate in the resting condition isolates the oral cavity from the

respiratory airways and makes the rat an obligatory nose breather (virtually

no oropharynx). Thus, the direction of flow in rats is almost linear whereas

in humans it is rectangular (for more details see DeSesso, Quality

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assurance Good Practice, Regulation, and Law 2, 213-231,1993). Apart

from these dosimetric issues a concentration dependent increase in the

extent of cell infiltration in the larynx, as indirect evidence of local irritation,

did not occur. Therefore, the metaplastic changes observed at this location

are considered to be causally related to adaptive (differentiation of cells to

become more resistant) rather than adverse effects.

Taking all findings into account, 1 mg/m3 constitutes a no-observedadverse-effect-level (NOAEL) for effects governed by respiratory tract

irritation.

Reliability : (1) valid without restriction

Flag : Critical study for SIDS endpoint

14.01.2005 (34)

Type : Sub-acute

Species : rat

Sex : male/female

Strain : Wistar

Route of admin. : inhalation: aerosol

Exposure period : two weeks before mating until day 19 of gestation

Frequency of treatm. : 7 x 6 hours/week

Post exposure period : 4-6 days (females)

Doses : 0, 1, 6, 36 mg/m3 (target concentration)

Control group : other: conditioned air

Method : other: see Test Condition 

Year : 2004

GLP : yes

Test substance : other TS: purity 99.5%

Remark : For the results on Reproduction/Developmental Toxicity see chapter 5.8.3

Result : MORTALITY: 

<= 6 mg/m3: no deaths

36 mg/m3: 2/24 deaths; one male was found dead during premating period

and one female has to be killed in moribund condition.

CLINICAL SIGNS:

at 6 mg/m3: serous nasal discharge; nostrils with red encrustation 

at 36 mg/m3 breathing symptoms and/or serous nasal discharge and

nostrils with red encrustation

BODY WEIGHT:

at 36 mg/m3 body weight retardation in both sexes

FOOD CONSUMPTION:

at 36 mg/m3 transient reduction in males

ORGAN WEIGHT:

at 36 mg/m3 increased lung (absolute/relative) weights in males

(14%/18%).

Test condition : According to OECD Guideline No. 421

ADMINISTRATION/EXPOSURE:

Type of exposure: nose-only exposure

Analytical concentrations: 0.00106, 0.00595, 0.03404 mg/l

Nominal concentrations: 0.005, 0.020, 0.119 mg/l

Particle size: mass median aerodynamic diameter: approx 1 um (geometric

standard deviation: approx. 2)

Reliability : (2) valid with restrictions

A study according to OECD TG 421 primarily examines the effects on

reproduction and development

Flag : Critical study for SIDS endpoint

22.12.2005 (35)

Type : Sub-acute

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Species : rat

Sex : no data

Strain : no data

Route of admin. : inhalation

Exposure period : 4 hours/day

Frequency of treatm. : 5 days/week during 2 weeks

Post exposure period : no data

Doses : 120 mg/l and 40 mg/m3

Control group : other: no data

Method : other: no data 

Year :

GLP : no data

Test substance : no data

Result : Clinical signs of marked respiratory irritation and

decreased growth rates were observed in rats exposed to 120 mg/m3. At

40 mg/m3 only an initial weight loss was observed

Reliability : (4) not assignable

Onyl an abstract available

14.01.2005 (61)

5.5 GENETIC TOXICITY ‘IN VITRO‘

Type : Bacterial gene mutation assay

System of testing : S. typhimurium TA 1535, TA 1537, TA 98, TA 100, TA 102

Test concentration : up to 50 μg/plate

Cycotoxic concentr. : 1.6 μg/plate

Metabolic activation : with and without

Result : negative

Method : OECD Guide-line 471

Year : 2005

GLP : yes

Test substance : other TS: Desmodur W; purity 99.5%

Remark : Appropriate reference mutagens (sodium azid, nitrofurantoin, 4-nito-1,2-

phenylene diamine, mitomycin C, cumene hydroperoxide and 2-

aminoanthracene) were used as positive controls and showed the

expected results.

Result : GENOTOXIC EFFECTS:

Evidence of mutagenic activity was not seen. No biologically relevant

increase in the mutant count, in comparison with the negative controls, was

observed.

CYTOTOXIC CONCENTRATION:

Doses up to and including 0.5 μg/plate did not cause any bacteriotoxic

effects. Total bacteria counts remained unchanged and no inhibition in

growth was observed. At higher doses, the substance had a strain-specific

bacteriotoxic effect. Nevertheless this range could partially be used up to

50 μg/plate for assessment purposes.

Test condition : SYSTEM OF TESTING:

1. experiment: Plate incorporation assay

2. experiment (= independent repeat): preincubation test

Metabolic activation system: S9 liver microsomal fraction of male Sprague

Dawley rats which received a single i.p. injection of Aroclor 1254

ADMINISTRATION:

concentration tested:

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1. and 2. experiment

without S9 mix:0.05, 0.16, 0.5, 1.6, 5.0, 16.0 μg/plate

with S9 mix: 0.16, 0.5, 1.6, 5.0, 16.0, 50 μg/plate

SOLVENT:

ethylene glycol dimethylether (EDGE) for the test substance and the

positive controls

deionized water for mitomycin C

Reliability : (1) valid without restriction

Flag : Critical study for SIDS endpoint

22.12.2005 (38)

Type : Ames test

System of testing : S. typhimurium TA 1535, TA 1537, TA 1536, TA 98, TA 100

Test concentration : up to 250 ug/plate

Cycotoxic concentr. : Pretest results are not reported

Metabolic activation : with and without

Result : negative

Method : other: see Test Condition

Year : 1977

GLP : no

Test substance : other TS: 4,4 ́-Methylenedicyclohexyl diisocyanate, no data on purity

Result : GENOTOXIC EFFECTS:

- without metabolic activation: no significant increase of revertants in any

strain (individual test results specified)

- with metabolic activation: no significant increase of revertants in any

strain (individual test results specified)

PRECIPITATION CONCENTRATION: no data

CYTOTOXIC CONCENTRATION: "Prior to testing for mutagenicity, the

compound was tested for toxicity to the tester strains." (no further

information available)

Test condition : SYSTEM OF TESTING:

Plate incorporation assay

Metabolic activation system: S9 liver microsomal fraction of rats

One experiment with one test plate (no replicates)

ADMINISTRATION:

concentrations tested: 

without S9 mix: 0.1, 0.2, 0.4, 0.6, 0.8 and 1 ug/plate; 

with S9 mix: 50, 100, 150, 200 and 250 ug/plate;

SOLVENT: aceton

- Positive and negative control groups and treatment

negative control: solvent

positive control: without metabolic activation

TA1535, TA100: N-Methyl-N-nitro-N-nitrosoguanidine

TA1537: 9-Aminoacridine

TA1538, TA98: 2-Nitrofluorene

with metabolic activation

for TA100: 2-Aminoanthracene (5 ug/plate)

TA98, TA1538, TA1535: 2-Aminoanthracene (10 ug/plate

TA1537: 2-Aminoanthracene (100 ug/plate)

Reliability : (2) valid with restrictions

The test design does not comply with the current guideline with regard to

the number and kind of applied strains; no independend repeat experiment

was performed, limited documenation (i.e. no data on S9-mix preparation,

no details of the pretest on toxicity to the tester strains)

Flag : Critical study for SIDS endpoint

22.12.2005 (53)

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Type : Chromosomal aberration test

System of testing : Chinese Hamster V79 Cells

Test concentration : 1.5, 3, 4.5, 6, 8 and 7.5 μg/ml without S9 mix and 6, 12, 20, 24 and 28

μg/ml with S9 mix (see also freetext TC)

Cycotoxic concentr. : 4.5 μg/ml without S9 mix and 12 μg/ml with S9 mix (see also freetext RS)

Metabolic activation : with and without

Result : negative

Method : OECD Guide-line 473

Year : 2004

GLP : yes

Test substance : other TS: Desmodur W, no data on purity

Remark : The positive controls mitomycin C and cyclophosphamide induced

clastogenic effects and demonstrated the sensitivity of the test system and

the activity of the used S9 mix.

Result : Without S9 mix cytotoxic effects were observed at 4.5 μg/ml and above

after 4 hours treatment and at 8 μg/ml and above after 18 hours treatment.

With S9 mix cytotoxic effects

were observed at 12 μg/ml and above. Precipitation in the medium was not

observed.

Therefore, concentrations of 4.5, 6 and 7.5 μg/ml test substance (4 hours

treatment) and 2.5, 5 and 8 μg/ml (18 hours treatment) were chosen for

reading in the absence of S9

mix. In the presence of S9 mix 6, 12 and 20 μg/ml of test substance were

employed. All of these cultures harvested 18 hours after the beginning of

the treatment were included. In addition, cultures treated in the absence of

S9 mix with 7.5 μg/ml and harvested 30 hours after the beginning of the

treatment were used. The same was true for cultures treated in the

presence of S9 mix with 20 μg/ml.

None of the cultures treated with test substance in the absence and in the

presence of S9 mix showed biologically relevant or statistically significant

increased numbers of aberrant metaphases.

Test condition : METABOLIC ACTIVATION:

S9 mix - from liver homogenates of with Aroclor 1254 induced male

Spargue Dawley rats. The S9 mix contained 40% S9 fraction.

CONTROLS:

Vehicle: DMSO

positive controls: mitomycin C (0.1 and 0.03 μg/ml); cyclophosphamide (2

μg/ml)

Initially Chinese hamster V79 cells were exposed in the absence of S9 mix

for 4 hours to concentrations of 1.5, 3, 4.5, 8 and 7.5 μg/ml of test

substance. Cultures of all concentrations were harvested 18 hours after the

beginning of the treatment. In addition, cells treated with 4.5, 6 and 7.5

μg/ml were harvested 30 hours after the beginning

of the treatment. In the presence of S9 mix cells were exposed for to

concentrations of 6, 12, 20, 24 and 28 μg/ml of test substance. Cultures of

all concentrations were harvested 18 hours after the beginning of the

treatment. In addition, cells treated with 20, 24 and 28 μg/ml were

harvested 30 hours after the beginning of the treatment. Without S9 mix an

additional experiment was performed using continuous treatment for 18

hours, harvest at the same time, and test substance-concentrations of 2.5,

5, 8, 1O and 12 μg/ml.

Based on their cytotoxicity, which was also determined 8 hours after the

beginning of the treatment, concentrations were selected for reading of

metaphases. 100 metaphases were scored for structural chromosome

aberrations.

Conclusion : Based on this test, the test substance is considered not to be clastogenic

for mammalian cells in vitro.

Reliability : (1) valid without restriction

Guideline Study

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Flag : Critical study for SIDS endpoint

13.01.2005 (36)

5.6 GENETIC TOXICITY ‘IN VIVO‘

5.7 CARCINOGENICITY

5.8.1 TOXICITY TO FERTILITY

5.8.2 DEVELOPMENTAL TOXICITY/TERATOGENICITY

Species : rat

Sex : female

Strain : Wistar

Route of admin. : other: nose only inhalation: aerosol

Exposure period : 6 hours

Frequency of treatm. : daily

Duration of test : from day 6 up to day 19 p.c.

Doses : 0, 1, 6, 36 mg/m3 (target concentration)

Control group : other: conditioned air

NOAEL maternal tox. : = 1 mg/m3

NOAEL teratogen. : = 6 mg/m3

Method : OECD Guide-line 414 "Teratogenicity"

Year : 2003

GLP : yes

Test substance : other TS: Desmodur W, purity 99.5%

Result : MATERNAL DATA:

Appearance, behavior, and mortality of the females were unaffected at the

1 mg/m3 level, while increased or decreased respiratory rates, labored

breathing, irregular

respiration, and sounds consistent with rhinitis occurred each before and

after inhalation at the 36 mg/m3 level. Furthermore, rough fur, piloerection

(one female,

one day only), serous nasal discharge, and reddish encrusted nostrils each

before and after inhalation, and reddish encrusted nose (one female, one

day only) occurred in the 36 mg/m3 group. 

Labored breathing after inhalation, piloerection before and after inhalation,

paleness before and after inhalation and and reddish encrusted nostrils

after inhalation occurred in single females at the 6 mg/m3 level; several

females had serous nasal discharge before (9 females) and after inhalation

(17 females) at this dose level.

Decreased feed intake (days 6-9 p.c.: approx. 22%; days 9-12 p.c.: approx.

8%), statistically significant transient body weight loss (approx. 5%) after

start of treatment (days 6-7 p.c.), resulting in a decreased body weight gain

during the treatment period (days 6-19 p.c., approx. 24%) and during

gestation (days 0-20 p.c., approx. 15%) occurred at the 36 mg/m3 level.

Mean corrected body weight gain was also marginally decreased (approx.

14%) at this dose level.

No treatment related gross pathological findings occurred at levels up to

and including 36 mg/m3.

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The gestation rate, appearance of placentas, placental weights,

postimplantation loss, number of live fetuses, fetal sex distribution, and

fetal weights were unaffected by treatment with the test material up to and

including the dose level of 36 mg/m3.

GENERAL REPRODUCTION DATA

The mean number of implantation sites were lower at 36 mg/m3, and a

slight increased preimplantation loss occured in this group, whereas the

mean number of corporalutea did not differ to meaningful extent, indicating

a homogeneous distribution regarding this parameter. The values in the 36

mg/m3 dose group were comparable to the normal range of scattering for

the rat strain used, and statistical significance was not evident for these

findings, so that treatment related unobserved early postimplantation loss

(which would not be detectable by staining the uterus, and would appear as

preimplantation loss) is unlikely.

Dose mg/m3: 0/ 1/ 6/ 36

Females with implantations in % of those inseminated: - 77.8 / 96.3/ 74.1 /

71.9

mean values per female with implantation sites

- corpora lutea: 15.0 / 14.4 / 14.1 / 14.7

- preimplantation loss: 1.8 / 1.4 / 1.7 / 2.8

- implantations: 13.2 / 13.0 / 12.4 / 11.8

FETAL DATA 

Dose mg/m3: 0/ 1/ 6/ 36

Means per female

- post implantation loss: 0.7 / 0.8 / 1.3 / 1.0

- Number of live fetuses: 12.6 / 12.2 / 11.2 / 10.8 

- fetal weights g: 3.51 / 3.53 / 3.40 / 3.55

- sex of live fetuses (% males): 55.3 / 51.8 / 50.5 / 51.8

FETAL MALFORMATIONS

A treatment related effect cannot completely be excluded for the marginally

increased incidence (1.2% versus 0.9% in historical controls) in of

ventricular septal defects of the heart (common finding) at the

level of 36 mg/m3, despite of a lower overall number of fetuses with

malformations at this dose level, as this dose showed clear maternal

toxicity.

Dose mg/m3: 0/ 1/ 6/ 36

- Number of fetuses per group: 264 / 317 / 224 / 248

- Number of fetuses with malformations: 9 / 5 / 5 / 4

- malformed fetuses per group (%): 3.4 / 1.6 / 2.2 / 1.6

- Number of litters per group: 21 / 26 / 20 / 23

- Number of litters with malformations: 6 / 4 / 5 / 4

- malformed litters per group (%): 28.6 / 15.4 / 25.0 / 17.4

- ventricular septal defect of the heart: 1 / 1 / 1 / 3

- number of litters affected by this malformation:

1 / 1 / 1 / 3

FETAL EXTERNAL AND VISCERAL DEVIATIONS

Meaningful external or visceral deviations of fetuses were not assumed at

dose levels up to and including 6 mg/m3. A treatment related effect for the

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significantly increased incidence of slight dilation of lateral brain ventricle(s)

(11.3% affected fetuses, 56.5% affected litters) at the 36 mg/m3 level is

unlikely, as the value lay within the range of historical control data and data

of different unaffected study groups used (up to 12.7% affected fetuses, up

to 65.5% affected litters).

Dose mg/m3: 0/ 1/ 6/ 36

- Number of fetuses per group: 264 / 317 / 224 / 248

- Number of fetuses with deviations: 59 / 60 / 48 / 53

- fetuses with deviations per group (%): 22.3 / 18.9 / 21.4 / 21.4

- Number of litters per group: 21 / 26 / 20 / 23

- Number of litters with deviations: 18 / 20 / 18 / 20

- litters with deviations per group (%): 85.7 / 76.9 / 90.0 / 87.0 

- slight dilation of lateral brain ventricle (s):

11 / 14 / 17 / 28

- number of litters affected by this deviation:

5 / 7 / 8 / 13

Test condition : TEST SYSTEM: 

inseminated Wistar rats

age: 13 - 15 weeks

body weight by study initiation: 201 - 245 g

no. of animals: 27 / dose (dose group 36 mg/m3 32 femals were treated)

CHARACTERIZATION OF TEST ATMOSPHERE:

Particle size determination of the aerosol yielded MMADs within the

respirable range (» 1 mm, the geometric standard deviation (GSD) » 2)

PARAMETERS ASSESSED DURING STUDY:

- Clinical observations: daily

- Body weights: day 0 p.c., daily (day 6-20 p.c.)

EXAMINED AT NECROPSY (MACROSCOPIC AND MICROSCOPIC): 

- gross pathological examination at the time of

cesarean section on day 20 p.c. without knowledge of treatment groups.

Investigations at Cesarean Section:

- Number of corpora lutea

- Number of implantations

- Uterine weights

- Number of early resorptions

- late resorptions

- dead fetuses

- Number of live fetuses

- Sex of live fetuses

- Individual weights of live fetuses

- External malformations 

- Visceral malformations

- Skeletal malformations

- External and visceral deviations

STATISTICAL METHODS:

Dunnett-Test with a variance analysis; Fisher’s exact CHI-SQUARE

(positive ANOVA probability test with a

significance levels of alpha=5%)

Reliability : (1) valid without restriction

Flag : Critical study for SIDS endpoint

14.01.2005 (37)

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5.8.3 TOXICITY TO REPRODUCTION, OTHER STUDIES

Type : other: Reproduction/Developmental Toxicity Screening

In vitro/in vivo : In vivo

Species : rat

Sex : male/female

Strain : Wistar

Route of admin. : inhalation

Exposure period : two weeks before mating until day 19 of gestation

Frequency of treatm. : 7 x 6 hours / week

Duration of test : 9 weeks

Doses : 0,1, 6, 36 mg/m3 (= target concentrations)

Control group : yes, concurrent no treatment

Result : NOAEL - General Toxicity: 1 mg/m3

NOAEL - Reproduction/Developmental Toxicity: 6 mg/m3

Method : other: according OECD guide-line 421

Year : 2003

GLP : yes

Test substance : other TS: Desmodur W, purity 99.5%

Result : At 36 mg/m3 changes in breathing behavior and/or serous nasal discharge

(nostrils with red encrustation) were noted in the majority of F0 rats. At 36

mg/m3 in single animals also signs of poor general conditions occurred and

slightly increased (2 of 24 rats) mortality was observed. One male of the

high dose group was found dead during the premating period and one

female of the high dose group has to be killed in moribund condition. At 6

mg/m3 only serous nasal discharge and red encrusted nostrils were noted

in F0 rats.

No toxic effect was seen on body weights of F0 rats up to 6 mg/m3. At 36

mg/m3 reduced body weight gain was noted at some time points in both

sexes (males: week 5-6: 2.8g vs. 9.8g in controls, week 4-5: 10.2g vs.

-1.2g in controls; females: week 1-2: -11.2g vs -4.7g in controls).

The food intake of 36 mg/m3 F0 males was transiently reduced. 

The absolute (14%) and relative (18%) weights of the lungs were increased

in 36 mg/m3 F0 male rats.

PARAMETERS OF REPRODUCTION

At 36 mg/m3 a slightly reduced fertility index was noted. 

No other reproduction parameter was affected.

Dose mg/m3: 0/ 1/ 6/ 36

Insemination index %: 100.0/ 91.7/ 100.0/ 100.0

Fertility index %: 91.7/ 81.8/ 83.8/ 66.7 (p > 0.05)

Gestation index %: 90.9/ 100.0/ 100.0/ 100.0

Gestation length Days: 22.11/ 22.25/ 22.22/ 22.00

Co-housed females n: 12/ 12/ 12/ 12

Number of implantation sites (per litter): 10.8 / 10.56 / 11.50 / 9.88

Litters alive n: 10/ 9/ 10/ 8

Live birth index %: 98.57 / 99.07 / 97.22 / 96.36

Viability index %: 99.00 / 100.0 / 92.17 / 98.96

SPERM ANALYSIS

Results of sperm analysis were excluded from the study evaluation,

because mechanical stress on the epididymides and testes caused by the

narrowness of exposure restrainers had induced untypical and test120
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compound independent low sperm motility ( below 30%) and increase in

sperm abnormalities ( higher than 50%) in all groups which corroborate

with testicular and epididymal changes seen histologically.

Dose mg/m3: 0 / 1 / 6 / 36

Sperm motility, (first min) %: 21 / 7 / 26 / 16

Sperm motility (fifth min) %: 18 / 6 / 25 / 15

Abnormal sperms %: 59.4 / 87.4 / 60.9 / 66.4

Mean number of spermatids per mg testis:

52773 / 41767 / 41989 / 49707

Mean number of sperms per mg epididymis:

490037 / 138194 / 347913 / 323042

HISTOPATHOLOGY

No test compound-related effects were seen in the testes and epididymides

of F0 rats.

In the testes of both groups evaluated (control and high dose) tubular

degeneration (mainly multi/focal) was seen in the majority of animals:

dose mg/m3: 0 ; 36 

Focal tubular degeneration: 5/12 ; 8/12

Dif. tubular degeneration: 2/12 ; 0/12

In the epididymides, spermatic debris and oligospermia occurred in almost

all rats.

dose mg/m3: 0 ; 36 

Spermatic debris: 12/12 ; 11/12

Oligospermia: 11/12 ; 10/12

The morphology of the ovaries of F0 females was not affected.

Data On PUPS (F1):

dose mg/m3: 0 / 1 / 6 / 36

- Live birth index %: 98.57 / 99.07 / 97.22 / 96.36

- Viability index %: 99.00 / 100.0 / 92.17 / 98.96

- Males %: 54.31 / 50.56 / 49.23 /53.90

No remarkable clinical signs were observed during the four day lactation

period up to 36 mg/m3. No effect on body weights and no macroscopical

alterations were noted at pup necropsies up to 36 mg/m3.

Test condition : ANIMALS:

12 male and 12 male Wistar rats /dose and control group

ADMINISTRATION / EXPOSURE

Type of exposure: nose-only exposure of an aerosol

Analytical concentrations: 1.06, 5.95, 34.04 mg/m3

Nominal concentrations: 5, 20, 119 mg/m3

Particle size: mass medien aerodynamic diameter: approx 1 um (geometric

standard deviation: approx. 2)

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- Treatment: The test substance was administered to parental (F0) animals

two weeks prior to and during their mating, during the resultant pregnancy

up day 19 p.c. Males were dosed 28 days at a minimum. For technical

reasons (to avoid withdrawal from their pups) females were not treated

during lactation.

MATING PROCEDURES: The F0 animals were pretreated with the

compound for 2 weeks up to the cohabitation period. During the following

mating period the first F0 male was cohoused

with the first female F0 animal within the group and so on over night at a

maximum of 12 times during the two-week mating period. As a rule

inseminated females were not further co-housed. Insemination was

established by investigating vaginal smears prepared in the morning.

PARAMETERS ASSESSED DURING STUDY F0: 

- Clinical observations: daily, detailed recordering at least once weekly

- Body weights: weekly; females additionally on day 0 and 4 after birth of

their pups

- Sperm examination: motility and viability, spermatozoa density per mg

epididymis, no of spermatid heads per mg testis

ORGANS EXAMINED AT NECROPSY (MACROSCOPIC AND

MICROSCOPIC): 

- Organ weights F0: lungs with trachea, left epididymis and testes 

- Histopathology F0: testes, epididymides and ovaries of controls and high

dose

OTHER EXAMINATIONS: 

- Indices: 

insemination, fertility, gestation, live birth, viability

PARAMETER ASSESSED ON F1:

- Number of live and dead pups 

- Sex of the pups 

- body weights

- clinical signs

- apparent malformations

were determined shortly after birth and on day 4 p.p..

STATISTICAL METHODS:

Dunnett-Test with a variance analysis; Fisher’s exact CHI-SQUARE

(positive ANOVA probability test with a

significance levels of alpha=5%)

Reliability : (1) valid without restriction

Flag : Critical study for SIDS endpoint

12.01.2005 (35)

5.9 SPECIFIC INVESTIGATIONS

5.10 EXPOSURE EXPERIENCE

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Remark : For information on human experience see also chapter 5.3

Flag : Critical study for SIDS endpoint

22.11.2004

Remark : There is a second reference on the same subject: Smirnov V, Sculsky M,

Israeli R (1981) Acute intoxication by organic iso cyanates. Harefuah 100

(11): 520-522, 551. It is published in Hebrew (study not available).

Result : To prevent glass injuries among onsumers glass bottles were coated with

polyurethane. 4,4 ́-Methylenedicyclohexyl diisocyanate was polymerized to

polyurethane for this purpose. 11/15 workers who were first exposed to 4,4

 ́-Methylenedicyclohexyl diisocyanate (no airborne concentration

determined but insufficient ventilation was admitted) showed allergic and

non-allergic skin reaction. 6 suffered from vertigo with and without

headaches and 4 developed a decrease of the obstructive lung function,

tachycardia and hypotension (EKG normaly); the symptoms appeared 4-7

days after the exposure and were reversible within 10-14 days

Test substance : 4,4 ́-Methylenedicyclohexyl diisocyanate, no data on purity

Reliability : (2) valid with restrictions

Limited documentation

Flag : Critical study for SIDS endpoint

06.11.2006 (66)

5.11 ADDITIONAL REMARKS

Remark : An overall perspective of the sensitization potential of Methylene bis(4-

cyclohexylisocyanate) is given

Reliability : (2) valid with restrictions

Data from a collection of data which was reviewed by an expert panel

23.11.2004 (68)

Remark : An overall perspective of acute animal and human studies with Methylene

bis(4-cyclohexylisocyanate) is given

Reliability : (2) valid with restrictions

Data from a collection of data which was reviewed by an expert panel

23.11.2004 (1)

Remark : An retrospective analysis of acute inhalation studies which shows for 4,4

 ́-methylenedicyclohexyl diisocyanate among each other that for irritant

aerosols both the concentration and the particle size are equally important

for the outcome of the test, independent of whether the endpoint chosen is

lethality or the protein in bronchoalveolar lavage fluid (BAL-protein).

Reliability : (2) valid with restrictions

Limited documentation; 4,4 ́-methylenedicyclohexyl diisocyanate is one of

a number of different diisocyanates for which a retrospective analysis is

performed

09.09.2004 (79)

Remark : A short description of the results from several toxicological studies (acute

oral, repeated oral, skin/eye irritation, skin sensitization) without any

information on details of study performance (incl. dosage).

Reliability : (4) not assignable

no study details are reported

06.11.2006 (72)

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124
OECD SIDS 4,4’-METHYLENEDICYCLOHEXYL DIISOCYANATE

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