Unclassified ENV/JM/MONO(2004)11

Organisation de Coopération et de Développement Economiques 

Organisation for Economic Co-operation and Development 24-Jun-2004 

___________________________________________________________________________________________

_____________ English - Or. English 

ENVIRONMENT DIRECTORATE 

JOINT MEETING OF THE CHEMICALS COMMITTEE AND 

THE WORKING PARTY ON CHEMICALS, PESTICIDES AND BIOTECHNOLOGY 

 

OECD SERIES ON EMISSION SCENARIO DOCUMENTS 

Number 6 

EMISSION SCENARIO DOCUMENT ON ADDITIVES IN RUBBER INDUSTRY 

JT00166668 

Document complet disponible sur OLIS dans son format d'origine 

Complete document available on OLIS in its original format 

Unclassified ENV/JM/MONO(2004)11 English - Or. English

 ENV/JM/MONO(2004)11 

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OECD Environmental Health and Safety Publications 

Series on Emission Scenario Documents No. 6 

EMISSION SCENARIO DOCUMENT ON 

ADDITIVES IN RUBBER INDUSTRY 

Environment Directorate 

Organisation for Economic Co-operation and Development 

June 2004 
ENV/JM/MONO(2004)11 

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ABOUT THE OECD 

 The Organisation for Economic Co-operation and Development (OECD) is an 

intergovernmental organisation in which representatives of 30 industrialised countries in North 

America, Europe and the Pacific, as well as the European Commission, meet to co-ordinate and 

harmonize policies, discuss issues of mutual concern, and work together to respond to international 

problems. Most of the OECD's work is carried out by more than 200 specialised Committees and 

subsidiary groups composed of Member country delegates. Observers from several countries with 

special status at the OECD, and from interested international organisations, attend many of the 

OECD's Workshops and other meetings. Committees and subsidiary groups are served by the OECD 

Secretariat, located in Paris, France, which is organised into Directorates and Divisions. 

 The Environmental Health and Safety (EHS) Division publishes documents in eight different 

series: Testing and Assessment; Good Laboratory Practice and Compliance Monitoring;

Pesticides; Risk Management; Harmonization of Regulatory Oversight in Biotechnology;

Chemical Accidents; Pollutant Release and Transfer Registers; and Emission Scenario 

Documents. 

 The Environmental Health and Safety Programme co-operates closely with other international 

organisations. This document was produced within the framework of the Inter-Organization 

Programme for the Sound Management of Chemicals (IOMC). 

The Inter-Organization Programme for the Sound Management of Chemicals 

(IOMC) was established in 1995 by UNEP, ILO, FAO, WHO, UNIDO and the 

OECD (the Participating Organizations), following recommendations made by the 

1992 UN Conference on Environment and Development to strengthen co-operation 

and increase international co-ordination in the field of chemical safety. UNITAR 

joined the IOMC in 1997 to become the seventh Participating Organization. The 

purpose of the IOMC is to promote co-ordination of the policies and activities 

pursued by the Participating Organizations, jointly or separately, to achieve the 

sound management of chemicals in relation to human health and the environment. 
 ENV/JM/MONO(2004)11 

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This publication is available electronically, at no charge. 

For the complete text of this and many other Environmental 

Health and Safety publications, consult the OECD’s 

World Wide Web site (http://www.oecd.org/ehs/) 

or contact: 

OECD Environment Directorate, 

Environmental Health and Safety Division

2 rue André-Pascal 

75775 Paris Cedex 16 

France 

Fax: (33-1) 45 24 16 75 

E-mail: ehscont@oecd.org 
ENV/JM/MONO(2004)11 

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Explanatory notes 

Purpose and background 

This OECD Emission Scenario Document (ESD) is intended to provide information on the 

sources, use patterns and release pathways of chemicals used as additives in rubber industry to assist 

in the estimation of releases of chemicals to the environment. 

This ESD should be seen as a ‘living’ document, which provides the most updated information 

available. As such, an ESD can be updated to take account of changes and new information, and 

extended to cover the industry area in countries other that the lead (Germany). Users of the document 

are encouraged to submit comments, corrections, updates and new information to the OECD 

Environment, Health and Safety Division (env.riskassessment@oecd.org). The comments received 

will be forwarded to the OECD Task Force on Environmental Exposure Assessment, which will 

review the comments every two years so that the lead country can update the document. The submitted 

information will also be made available to users within the OECD web-site 

(www.oecd.org/env/riskassessment). 

How to use this document 

The user of this ESD needs to consider how the information contained in the document covers the 

situation for which they wish to estimate releases of chemicals. The document could be used as a 

framework to identify the information needed, or the approaches in the document could be used 

together with the suggested default values to provide estimates. Where specific information is 

available it should be used in preference to the defaults. At all times, the values inputted and the 

results should be critically reviewed to assure their validity and appropriateness. 

For the estimation of the emissions of chemicals used as additives in the rubber industry the 

following data and information should be available: 

• function of the additive 

• type of rubber product 

• amount of rubber product produced per day (default) 

• percentage of additive introduced into the rubber product 

• fraction of additive remaining in the rubber product (default). 

Coverage 

This ESD describes the life cycle stages of rubber additives in formulation, use, and service life 

(tyre abrasion), and provides emission estimations to local surface waters, air and soil. The industry 

categories, use categories and biocidal product types relevant to this document are as follows. 

Industry category Use Category Biocidal product type 

11 – polymer industry 20 – fillers 

22 – flame retardants and fire 

preventing agents 

49 – stabilisers 

53 – vulcanising agents 
 ENV/JM/MONO(2004)11 

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How this document was developed 

In the year 1999, Umweltbundesamt (UBA Germany) commissioned the Institute for 

Environmental Research, University of Dortmund (INFU) (contract no 360 01 27/3; 

http://www.oekopro.de) to develop this ESD. In 2001, Umweltbundesamt integrated comments 

received from RIVM (The Netherlands) and adjusted the nomenclature to the agreed EU nomenclature 

(http://ecb.jrc.it - biocides). This ESD was published in the European Union Technical Guidance 

Document on Risk Assessment [EU 2003, Part IV]. 

Germany (Umweltbundesamt) as the lead country submitted this draft to OECD, and the draft 

was circulated to the member countries in February 2002. Comments were received from the 

following organizations and institutions: UK (Environment Agency and Health and Safety Executive), 

US EPA and US industries, Canada [OECD, 2002]. Umweltbundesamt incorporated these comments 

in consultation with the Institute for Environmental Research, University of Dortmund (INFU) and the 

Association of the German Rubber Industry and amended the document with two new sections: 

• Emission scenario for formulation and processing to air and soil 

• Emission scenario for use of rubber products by tyre abrasion (service life). 

Releases from leachates in landfill and to sea or fresh water are not covered yet and need to be 

considered in the next version. 

The OECD Task Force for Environmental Exposure Assessment concluded at its 10th session (8 

April 2003) that this ESD is to be subsumed under the Industry Category 11 “Polymer Industry” new 

subsection “rubber additives”. 
ENV/JM/MONO(2004)11 

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Contents

1. INTRODUCTION .................................................................................................................................. 9

2. INDUSTRY SUMMARY AND BACKGROUND.............................................................................. 10

3. MAIN PROCESSES............................................................................................................................. 12

3.1 Natural- and synthetic Rubber..................................................................................................... 15

3.1.1 Mastication and Creation of Mixtures .................................................................................... 15

3.1.2 Shaping ................................................................................................................................... 16

3.1.3 Vulcanisation / Curing ............................................................................................................ 16

3.2 Latex............................................................................................................................................ 17

3.3 Rubber-Metal .............................................................................................................................. 17

3.4 Chemicals and Additives............................................................................................................. 17

4. EMISSION SCENARIOS .................................................................................................................... 21

4.1 Definition of the generic Point Source........................................................................................ 22

4.2 Emission Rate Estimation ........................................................................................................... 24

4.3 Emission Scenario for Formulation and Processing to Wastewater............................................ 25

4.4 Emission Scenarios for Formulation and Processing to Air and Soil.......................................... 30

4.5 Emission Scenario for Use of Rubber Products by Tyre Abrasion ............................................. 31

4.6 Emissions from Leachates........................................................................................................... 32

5. EXAMPLES OF EMISSION ESTIMATION...................................................................................... 33

5.1 Emissions from Formulation and Processing to Wastewater...................................................... 33

5.2 Emissions from Formulation and Processing to Air resp. Soil.................................................... 35

5.3 Emission from Abrasion of Tyres ............................................................................................... 35

6. REFERENCES ..................................................................................................................................... 36

7. GLOSSARY ......................................................................................................................................... 37

8. ABBREVIATIONS .............................................................................................................................. 39
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1. INTRODUCTION 

1. This document provides guidance for estimation of emissions from chemicals used as additives in 

the rubber industry (IC-11 Polymer industry), including additives like vulcanising agents (UC-53), anti 

ageing agents, fillers (UC-20), pigments, stabilizer (UC-49), plasticisers, processing aids, flame retardants 

(UC-22). 

2. The emissions during “industrial use” depend on the type and formulation of the additive and the 

processes. The two life-cycle phases “formulation” and “industrial use” can often not be separated and are 

therefore combined for this emission estimation. The processing steps taken into account are: 

• the creation of the rubber mixture 

• the mastication 

• the shaping 

• the vulcanisation 

• the finishing 

3. Additives may enter the environmental compartments water, air, and soil. The major pathway is 

the entry into water. This occurs in those processes, where water is used as cooling or heating medium, in 

vulcanisation, where water has direct contact with the rubber mixture. Releases to water can also occur in 

cleaning steps throughout these processes. The water pathway is the predominant one and is described in 

this document by a generic point source. For most additives, the air pathway is of minor importance. 

4. A regional scenario of tyre abrasion describes the phase „service life“ with subsequent leaching 

into surface water and soil. The phase “waste disposal” means the leaching potential by rainwater to the 

soil and water compartment or when used tyres are in contact with fresh or marine water. Mainly volatile 

monomers and plasticisers escape to the air compartment. A waste disposal scenario is not covered in this 

document. 
ENV/JM/MONO(2004)11 

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2. INDUSTRY SUMMARY AND BACKGROUND 

5. The EU produces only synthetic rubber. The total production of synthetic rubber amounted to 

2.51 million tonnes in the year 2001 (International Rubber Study Group 2003). This is about 25% of the 

world production. Unlike natural rubber, synthetic rubber is subject to strong fluctuations in the amount 

used and produced. This raw material was used to produce about one million tonnes of tyres and about 

530.000 tonnes of rubber products (“technical and other elastomer products”) in 1995. Table 1 shows the 

production of different EU countries, and Table 2 provides the market share of different synthetic rubber 

types characterised by the monomers used in the production. The world production of natural rubber grew 

from 3 million tonnes (1980) to 7.13 million tonnes in 2001 (International Rubber Study Group 2003). 

Table 1 Production and Consumption of Rubber (1996) 

 Country synthetic rubber 

production 

[1000 tonnes] 

synthetic rubber 

consumption 

[1000 tonnes] 

natural rubber 

consumption 

[1000 tonnes] 

Spain 83.7 0 124.9 

Italy 317.2 349 119.4 

Turkey 40.1 0 0 

France 565.8 403.6 209.7 

Belgium 139.6 0 51.9 

Germany 573.4 611.3 211.8 

Netherlands 215.7 0 66.6 

United Kingdom 306 268.9 140.4 

Source: Rubber Statistics, Rubber Statistical Bulletin Vol. 51, No 10 (1997). 

http://www.rubberstudy.com - Statistics. 

Table 2 Market Shares of different synthetic Rubber Types in the EU 

Rubber type Market share [%] 

Styrene butadiene rubber (SBR) 58 

butadiene rubber (BR) 14 

ethylene propylene diene rubber 

(EPCM) 

10 

Isoprene rubber (IR) 1 

Isoprene isobutylene rubber (IIR) 5 

acrylonitrile butadiene rubber (NBR) 7 

poly-2-chlorobutadiene (CR) 5 

Source: Rubber Statistics, Rubber Statistical Bulletin Vol. 51, No 10 (1997). 

http://www.rubberstudy.com - Statistics. 

6. The following Table 3 presents different rubber products and their percentages of uses. This 

distribution does not fluctuate over the years; it is assumed to be valid for all EU countries. 
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Table 3 Distributions of Rubber Products in Germany 

Rubber products Percentage [%] 

form products, rubber-metal-compounds 24 

Technical tubes and profiles 23 

glues, mixture, repair material 13 

other rubber products 11 

foam, micro cellular and cellular rubber 

products 

10 

Conveyor belts, flat and vee-belts 9 

other technical products 5 

sole material 3 

sheet material, punching products 2 

Sum 100 

Source: Association of the German Rubber Industry 1990: leaflet 
ENV/JM/MONO(2004)11 

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3. MAIN PROCESSES 

7. It is helpful to define three terms that are used in the rubber industry [Ullmann 1993]: 

• Rubber (raw rubber) is a non-cross-linked, but cross-linkable (curable, vulcanisable) polymer 

with rubber-elastic properties at room temperature. At higher temperatures and/or, if exposed to 

deforming forces, rubber demonstrates an increasing tendency for viscous flow. Therefore, it can 

be formed under appropriate conditions. 

• Elastomers are polymeric material that is cross-linked (vulcanised). They are hard and glassy at 

low temperature and do not exhibit viscous flow even at high temperature. Rubber elastic 

behaviour is characterised by a relatively low shear modulus with comparably low temperature 

dependency. 

• Vulcanisation is a process in which rubber, through a change in its chemical structure (for 

example, cross-linking) is converted to a condition, in which the elastic properties are conferred 

or re-established or improved or extended over a greater range of temperature. 

8. Natural rubber differs from synthetic rubber. Natural rubber is made from the milk of the rubber 

tree. This rubber milk is also called latex and is a colloidal dispersion in an aqueous medium. The latex 

concentration after tapping is about 30%. Only a small percentage is used directly; the greatest part is 

processed into harder rubber. This is done through evaporation, hydro extracting, creaming and electro 

decanting. Thailand is the most important producer of natural rubber. The raw rubber material is exported 

into the processing countries in the solid form. 

9. Natural rubber demonstrates a balanced combination of physical attributes resulting in a broad 

range of possible uses [Ullmann 1993]. A certain synthetic rubber surpasses every single attribute of a 

natural rubber. If these attributes are specifically required, the appropriate synthetic rubber will be used 

instead of the natural rubber. 

10. The most important types of synthetic rubber are shown in Table 2 in relation to their market 

shares. Almost two thirds of the total rubbers currently used in industry are synthetic. These rubbers are 

made from monomers like butadiene, styrene, acrylonitrile and isobutene. Table 4 characterises the 

attributes of these rubbers. There are many more synthetic rubbers than shown in the Table [Baumann and 

Ismeier 1998; Ullmann 1993]. 

11. Depending on the production procedure, one differentiates between polymerisates, 

polycondensates and polyaddition products. According to DIN ISO 1629 rubbers in the form of hard 

rubbers and latex are divided into groups depending on the chemical structure of the polymer chains. The 

rubber types are divided by their attributes [Lüpfert 1990] and their functions [Rentel et al. 1991]. A rubber 

is made mainly of [Lüpfert 1991] 

• polymers (elastomers) 

• fillers 

• plasticisers 
 ENV/JM/MONO(2004)11 

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• anti ageing agents 

• linking systems. 

12. Additives are added before and during processing. After the initial composition the mixture is 

created with an internal mixer, a rolling mill, a batch-off-facility and an extruder. The shaping of the semifinished product is made with an extruder, a plunger type injection moulder, through calendaring, the 

spreading machine and assembly. 

13. The compression process, the transfer moulding, and injection moulding are used for 

vulcanisation (curing) in presses. A continuous vulcanisation is made with the rotational vulcanisation, the 

steam pipe vulcanisation, the hot-air vulcanisation with microwave preheating, the boiling bed 

vulcanisation and the salt-bath vulcanisation. In addition to these, vulcanisation can also be accomplished 

in an autoclave. 
ENV/JM/MONO(2004)11 

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Table 4 Rubber Type and Additives 

Abbreviation Rubber Type Mixture 

NR Natural Rubber 

 proteins (cis-1,4-polyisoprene) 

 aliphatic acids vulcanisation agents (sulfur) 

resins vulcanisation accelerators

ash anti ageing agents 

sugar fillers

Water plasticisers

 processing aids

 

SR Synthetic Rubber 

SBR styrene butadiene rubber monomers (1,3-butadiene, styrene) 

 vulcanisation agents (sulfur) 

 vulcanisation accelerators 

 anti ageing agents 

 fillers 

 plasticisers 

 factices 

 resins 

 processing aids 

BR butadiene rubber monomers (1,3-butadiene) 

 vulcanisation agents (sulfur) 

 vulcanisation accelerators 

 anti ageing agents 

 fillers 

 plasticisers 

 processing aids 

NBR Acrylonitrile butadiene rubber monomers (1,3-butadiene, acrylonitrile) 

 vulcanisation agents (sulfur) 

 vulcanisation accelerators 

 anti ageing agents 

 fillers 

 plasticisers 

 factices 

 processing aids 

CR poly-2-chlorobutadiene monomers (chloroprene) 

 (polychloroprene) vulcanisation agents (sulfur) 

 vulcanisation accelerators 

 anti ageing agents 

 fillers 

 plasticisers 

 factices 

 processing aids 

EPDM ethylene propylene diene rubber monomers (ethylene, propylene) 

 vulcanisation agents 

 vulcanisation accelerators 

 anti ageing agents 

 fillers 

 plasticisers 

 processing aids 

IR isoprene rubber monomers (isoprene) 

 vulcanisation agents
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Abbreviation Rubber Type Mixture 

 vulcanisation accelerators

 anti ageing agents

 fillers

 plasticisers

 processing aids 

IIR isoprene isobutylene rubber monomers (isoprene, isobutylene) 

 vulcanisation agents 

 vulcanisation accelerators 

 vulcanisation activators 

 anti ageing agents 

 fillers 

 plasticisers 

 processing aids 

OTHER Special monomers 

 vulcanisation agents

 vulcanisation accelerators

 anti ageing agents

 fillers

 plasticisers

 processing aids

3.1 Natural- and synthetic Rubber 

3.1.1 Mastication and Creation of Mixtures 

14. The mastication is a process, in which the length of the polymer chains is decreased to lower the 

viscosity. This is necessary to get a better workability of the rubber (extrusion, calender and others) and to 

spread the rubber chemicals throughout the matrix. Rubber additives like anti ageing agents, fillers, 

plasticisers are discussed in Subsection 3.4. Their functions are shown in Table 5. 

15. An optimised viscosity is especially important for the production of rubber blends, since a 

homogenous distribution of the constituents is only possible within an equal viscosity. Unlike synthetic 

rubber, which can often be processed without a previous mastication, natural rubber is usually offered as a 

relatively hard product with little plasticity, making mastication a requirement. 

16. The mastication can be achieved in a purely mechanical process, in a mechanic-thermal process, 

physically by adding plasticisers and/or processing agents as well as chemically. 

17. Machines like rolling mills, the internal mixer or the gordon-plasticator masticate the rubber 

substance but also serve as mixers, for cooling, to finish the mixing of half ready rubber mixtures and to 

preheat finished rubber mixtures. A possible contamination of the water compartment during the mixing 

process can happen through the cooling process, if water is used as a direct cooling agent. Finally sulfur is 

added to the mixture. The finished mixture is taken off as a rough sheet. This rough sheet is cooled by 

immersion in water to which an anti tack-agent has been added (rolling mill). Especially in larger 

companies, the internal mixer replaced the rolling mill. An internal mixer can hold 15 to 650 litres. For the 

homogenisation, cooling and working into sheets rolling mills are still used. In modern installations, a 

batch off machine is responsible for taking off the sheets and immersing them in a bath of water or a bath 

with an anti tack-agent. 
ENV/JM/MONO(2004)11 

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3.1.2 Shaping 

18. Rubber mixtures are usually not immediately reprocessed after the mixture was created, but are 

stored in a cool and dry environment. For the shaping, processes like extrusion, calendering, form 

moulding and transfer moulding are used. 

19. Injection machines (extrusion plants) form rubber mixtures into bars, tubes, profiles, treads of 

tyres or sheets or encase cables and wires. In a continuous process, the rubber mixture is cured 

immediately after extrusion. If reprocessing as a semi-finished product is planned, the mixture is dusted 

and drawn through an adherent bath. Calendering is used to create sheets for the rubberisation of technical 

weaves (fractioning) and to coat weaves with a thin rubber sheet (skimming). 

20. Formed articles are mass articles like stoppers, bottle caps, soles, packing rings, collars, 

membranes, valve balls, buffers and tyres. Processes like pressing, transfer moulding, flashless-processes 

and the injection-moulding process are characterised by shaping and vulcanisation in one step. An 

assembly line takes an important role in this context. 

21. After the forms were used in a transfer moulding process over time, organic residues from the 

rubber mixture or from the anti tack-agents deposit as incrustation or carbonisation. A chrome sulfur bath 

(60°C) is used to clean the forms. The actual cleaning takes place in a lapping machine with a suspension 

of quartz flour. Water is used for rinsing the cleaned forms. 

3.1.3 Vulcanisation / Curing 

22. Vulcanisation is a chemical process to link the polymer structure. The term vulcanisation is used 

for a linking procedure, during which the macromolecules of the rubber are linked to each other over 

linking bridges. The linking is achieved with vulcanisation agents, usually sulfur, sulfur producers or 

peroxides as well as energy rich radiation. 

23. If uncured, rubber is thermoplastic. The molecules are not connected to each other. During 

vulcanisation the rubber changes from the thermoplastic to the elastic condition. The number of links 

depends on the amount of linking substances, their activity and reaction time. The following procedures are 

used for vulcanisation: 

• liquid curing method (LCM-Vulcanisation) 

• boiling bed vulcanisation 

• hot air vulcanisation after UHF-preheating 

• vulcanisation in hot steam under high voltage (under lead). 

24. The LCM-vulcanisation is commonly used for extruded profiles, tubes and similar processes. It is 

continuous and takes place in a liquid bath. The duration of the bath depends on the vulcanisation speed, 

the injection performance of the extrusion plant, the temperature of the heating bath and other factors. 

Eutectic salt mixtures (as well as glycerin, silicon oils, polyalkyleneglycole, metal mixtures) are used as a 

heating medium. For the boiling bed vulcanisation, small glass beads are used through which gas flows to 

lift them. 

25. The HF vulcanisation uses a pressure-free continuous process. The vulcanisation in steam pipes 

is used almost exclusively in the cable industry. Immediately after coating, the cable is guided into a pipe, 
 ENV/JM/MONO(2004)11 

 17

in which the steam pressure is usually between 0,5 and 1,2 MPa 

(max. 2 MPa). To reduce deformations, the vulcanisation is sometimes performed under a lead coating, this 

coating protects from the hydrolytical effect of the steam. After cooling with water, the lead coat is 

removed. 

26. The vulcanisation of calendared products can be achieved with rotational vulcanisation or in 

vulcanisation presses. A high frequency preheating is possible. Assembled rubber products are vulcanised 

free (not in a mould) in an open heater (hot air vulcanisation). 

27. To decrease the vulcanisation time, a steam heater is used. When using saturated vapour, in 

which water and steam are in balance, the temperature transference is more even. To avoid condensation 

spots, spreading agents are used. When vulcanising in water, the temperature transfer is extremely good 

compared to a medium of air or steam. This process will be used for big parts. It is used rarely for example 

for the vulcanisation of large rolls due to the complexity of the process. Vulcanisation can also be achieved 

through cold vulcanisation or energy rich radiation. 

3.2 Latex 

28. Natural latexes and synthetic latexes (as are created during the emulsion polymerisation) are 

processed, among other things into thin-walled products. The mixture is prepared by kneading the required 

chemicals into the latex solution. The coagulation process is used to create thick-walled products. The form 

is submerged in an alcoholic solution of a coagulation substance. This results in a thicker coagulum on the 

form as in other submerging processes. The vulcanised products must then be thoroughly rinsed with water 

to remove the coagulation substance. 

29. For foam rubber, steam or hot water is used as a medium for the vulcanisation. The spinning 

process for the creation of latex strings also requires water to rinse out the coagulator. 

30. Products made from unwoven textiles are made from bonded fabrics impregnated with a latex 

mixture. The unused adhesive is pressed out and the damp fabric dried and vulcanised. Leftover chemicals 

(emulsifying agents, stabilisers) are removed by washing. 

3.3 Rubber-Metal 

31. Metal working takes place in the rubber industry wherever composite parts made of rubber and 

metal are needed. One example is the tyre, which, in addition to a multitude of rubber mixtures, includes 

stabilising material like steel, textiles or plastic. Other rubber-metal parts for the automobile industry are 

shock absorbers, elastomere springs, coupling parts, hangers and others. Rubberised parts, like rolls are 

used in other areas. For the preparation of composite parts, spray- and degreasing plants are used. 

3.4 Chemicals and Additives 

32. The rubber industry uses hundreds of different substances. The finished product gains the 

required attributes only by adding fillers, plasticisers, vulcanisation chemicals, anti ageing agents and 

adhesives. Table 5 lists the most important process steps for the production of rubber and the most 

important substance classes used in each step. 

33. The rubber industry uses a special unit for expressing the components of a rubber mixture. They 

are presented in relation to 100 mass parts total rubber (parts per hundred rubber [phr]) or in wt-% (cf. 

Table 9) 
ENV/JM/MONO(2004)11 

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Table 5 Functions of Additives in Rubber Processing Steps 

Process Step / 

Additive 

Description Function of the Chemicals used 

Mastication plastification of the rubber 1. mastication agents 

 before working the molecular 2. activators (Boosters) 

 chain splitting through oxidative 

breakdown (usually aromatic or 

heterocyclic mercaptan). By using 

activators, the mastication can be shifted 

to a lower temperature spectrum (inner 

complex salts). 

Vulcanisation For linking the rubber molecules Vulcanisation agents 

 And creating linking bridges Vulcanisation accelerators 

 (usually sulfur, Vulcanisation activators 

Vulcanisation Sulfur producers, peroxides) Vulcanisation retarders 

Anti-ageing agents finished product with protection 

against damaging influences. 

1. antioxidants 

 2. anti fatigue agents 

 3. anti ozonants 

 4. light protection agents 

 5. anti hydrolysis agents 

 6. agents against metal poisoning 

 7. desactivators 

 8. reversion protection agents 

 9. anti cyclisation agents 

 

Fillers substances which are insoluble inorganic fillers 

 towards the rubber matrix, organic fillers 

 non-volatile and inert towards the 

polymer. The fillers define the attribute of 

the vulcanisate. They extend and 

strengthen the vulcanisate. 

Plasticisers plasticisers serve as extensions, they 

improve the fluidity, they distribute the 

fillers, improve the workability and the 

adhesiveness. They influence the physical 

attributes of the rubber like expansion and 

elasticity. Primary plasticisers have a 

loosening effect and lower the viscosity of 

non-vulcanisated rubber mixtures. 

Secondary plasticisers serve as lubricants 

and improve the shapeability. 

Plasticisers 

(categories: mineral oils, natural substances, 

synthetic plasticisers) 

Pigments/ pigments are in rubber de facto 1. inorganic pigments: 

Colourants insoluble, organic or inorganic, a) white pigments 

 coloured or white substances. b) coloured pigments 

 !"organic pigments 

 

Processing aids processing aids ease the working of the 

material: 

 1. lubricants are used mainly in the 

extrusion and the injection moulding 

processes 

1. lubricants 

# Metal soaps (like zinc-, calcium-soaps) 

# Aliphatic acids, Aliphatic acid ester 
 ENV/JM/MONO(2004)11 

 19

Process Step / 

Additive 

Description Function of the Chemicals used 

 2. tackifiers serve to increase the 

assembly adhesion 

2. tackifier 

Processing aids 3. among others to improve the stability, 

the injectability and calendrability 

3. factice 

Processing aids 4. by using fillers activators, the activity 

of the fillers can be improved 

4. fillers activators, adhesion agents 

 5. blowing agents are used to produce 

porous rubber articles (decompose under 

gas splitting) 

5. blowing agents 

 $"inorganic 

 $"organic 

 6. bonding agents increase the adhesion of 

rubber on strengthening material (weaves, 

metal) 

6. bonding agents 

 

other agents 1. anticyclisation agents serve to prevent 

unwanted cyclisation during mastication 

1. anti cyclisation agents 

 2. with the aid of replastication agents 

slightly vulcanized mixtures can be 

returned to a workable condition 

(desulfuring of the rubber mixture) 

2. replastication agents 

 3. emulsifier disperse systems 3. emulsifier 

 4. flame retardant lower the flammability 

of the rubber 

4. flame retardant 

 5. in solvent adhesives, in solvent dipping 

processes, for cleaning 

5. solvents 

 6. for refining the surface 6. surface treatment agents 

 7. to increase the hardness of the 

vulcanisate 

7. hardeners 

 8. to nuance, neutralize and cover the 

rubber smell 

8. odorants 

 9. to increase the electronic conductibility 9. antistatic agents 

 10. to kill microorganisms 10. microbiocides 

 11. to prevent the spreading of germs 11. anti termite agents 

 

Latex- to add pulverised additives into 1. dispersion agents 

chemicals the aqueous colloidal latex 2. emulsifier 

 Solution 3. stabiliser 

 4. wetting and foaming agents 

 5. foam stabilisers 

 6. thickeners 

 7. coagulating agents 

 8. preservatives 

 9. vulcanisation chemicals 

Latex- 10. anti ageing agents 

chemicals 11. fillers 

 12. plasticisers 

 
ENV/JM/MONO(2004)11 

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Process Step / 

Additive 

Description Function of the Chemicals used 

Release agents 1. prevent non-vulcanised rubber mixtures 

from adhering during storage 

1. release agents for non-vulcanised rubber mixtures 

(anti tack agents) 

 2. prevent rubber from sticking to the 

forming tools 

2. mould release agents 

 3. release agents are added to the rubber 

mixture, migrate to the surface and 

improve the removability of the 

vulcanisate from the form 

3. mandrel release agents 
 ENV/JM/MONO(2004)11 

 21

4. EMISSION SCENARIOS 

34. This document describes three generic emission scenarios: 

• formulation and processing: emissions to wastewater 

• formulation and processing: emissions to air and soil 

• private use of rubber products by tyre abrasion: emissions to surface water and soil. 

35. The contamination of water in the rubber industry takes place in several phases of the rubber 

production, whenever water comes into direct contact with the rubber product. This happens during 

cooling-, heating-, vulcanisation- and cleaning operations. Examples are direct cooling during the extrusion 

or direct contact of the material vulcanised with the steam in the vulcanisation processes. 

36. The sources and possible contaminations of wastewater are presented in Table 6. The water can 

contain zinc (zinc compounds are often used in anti tack agents), cadmium, copper and lead from 

vulcanisation. Storing, weighing, mixing are other possible sources of exposure. 

37. By using wastewater free procedures (indirect cooling, circulation systems, dry cleaning) releases 

to water can be avoided. A cascading arrangement of the rinsing baths and an optimised water flow can 

also decrease the volume of wastewater. The remaining wastewater is treated, if the pollutant concentration 

makes it necessary. Degreasing is accomplished with chlorinated hydrocarbons and complex builders like 

EDTA. The reduction or prevention of hazardous substances from the cleaning operations can be 

accomplished by degreasing on an aqueous basis. 

Table 6 Water Contamination of different Sources in the Rubber Industry [in mg.L-1] (Association of the 

German Rubber Industry 1999) 1

Source COD2 C3 SLS4 AOX5 BTX6 NO2 Ptotal Pb Cu Zn Cd 

 

direct cooling water and 

anti tack agent contact 

after mixing 

3000 

(RP) 

 1.5 

(RP) 

 0.54 

(TI) 

1.0 

(RP) 

<0.005 

(TI) 

 

1

 This table gives an overview about individual situations of special rubber manufacturers. It is not a generalisation of 

the emission situation. 

2

 Chemical oxygen demand 

3

 Hydrocarbons 

4

 Semivolatile lipophilic substance 

5

 Adsorbable organic halogen compounds 

6

 Benzene, Toluene, Xylene 
ENV/JM/MONO(2004)11 

 22

Source COD2 C3 SLS4 AOX5 BTX6 NO2 Ptotal Pb Cu Zn Cd 

 

direct cooling water 

after extrusion 

5 

(RP) 

 <0.05 

(RP) 

 0.06 

0.12 

0.052 

0.084 

(TI) 

<0.1 

(RP) 

<0.001 

(TI) 

<0.005 

(TI) 

<0.02 

(RP) 

wastewater from the 

waste air treatment 

during the production 

and processing of 

solutions after 

pretreatment (stripping) 

ca. 

6000 

35000 

I 

1000 

(RP) 

 0.1 O 

(RP) 

0.03-

0.2 

(RP) 

 0.1 I 

8.1 O 

 

wastewater from 

vulcanisation in forms 

as well as subsequent 

washing and cleaning 

processes 

282 

(TI) 

 0.065 

(TI) 

0.14 

(TI) 

6.8 

(TI) 

wastewater from 

vulcanisation in 

autoclaves as well as 

subsequent washing and 

cleaning processes 

65 

(RP) 

1100 

(RP) 

301 

(RP) 

233 

(RP) 

0.23 

(RP) 

0.05 

(RP) 

 3.3 

(TI) 

0.2 

(RP) 

<0.03 

(TI) 

0.16 

(RP) 

0.02 

(RP) 

0.05 

(RP) 

0.22 

(RP) 

0.87 

(RP) 

<0.002 

(RP) 

ca. 0.05 

(RP) 

wastewater from 

vulcanisation in a salt 

bath as well as 

subsequent washing and 

cleaning processes 

 1500 

(RP) 

 

wastewater from 

general cleaning of 

production tools 

540 

(TI) 

2000 I

1200 

O 

(RP) 

87 

(TI) 

0.05 

O 

(RP) 

28 O 

(RP) 

80 

(TI) 

>3.0 I 

<1.0 

O 

(RP) 

 <1 

(TI) 

41 I 

6.6 O 

5.8 I 

0.01 

O 

(RP) 

2.2 I 

0.02 

O 

(RP) 

38.5 I 

0.2 O 

(RP) 

 I: inflow, O: outflow of the waste water treatment plant 

TI = tyre industry, RP = rubber products 

4.1 Definition of the generic Point Source 

38. The generic point source for the rubber industry derived in this sub-chapter is related to the 

German situation. However, it is believed that the size of a typical manufacturer in the EU Member states 

is comparable, because of the general structure of the rubber industry. This generic point source is the 

reasonable worst case used in the environmental exposure assessment. Similar considerations can be 

followed in deriving the generic point source in non-EU Member states of the OECD. 

39. The emissions of the generic point source are derived from a survey of the wastewater discharges 

in the rubber industry. This total wastewater stream can be divided into the following component waste 

streams: sanitary, rainwater, metalworking, rubber working and others. The total quantities discharged 

each day are shown in Figure 1. The Association of the German Rubber Industry (1999) provided these 

discharge volumes and the following assumptions. 
 ENV/JM/MONO(2004)11 

 23

sanitary rainwater

metal

working rubber

processing other

indirect discharge

direct discharge

0

1

2

3

4

5

6

7

8

9

1000 m3/d

Figure 1 Volume of Component Wastewater Streams of direct and indirect Discharge for Members of the 

Association of the German Rubber Industry (1999) 

40. The Association of the German Rubber Industry (1999) recorded these wastewater data for 18 

direct dischargers (facility owned sewage treatment plant) and 70 indirect dischargers (via the municipal 

sewage treatment plant), 88 companies in total. It should be noted, that three companies discharged 75% of 

the total volume directly, and one indirect discharger made up for 30% of the corresponding discharge. 

This wastewater volume covers not only the rubber processing, but also the sanitary, metalworking and 

other areas. It is assumed that 37 % of the wastewater is attributed to rubber processing. Table 7 lists the 

statistical wastewater data for determining the generic point source. 

Table 7 Statistical Data for determining the generic Point Source 

Quantity of Wastewater (1) Flow rate [m3.d-1] 

Qwwat (arithmetic average) 184 

Qwwat (minimum) 10 

Qwwat (maximum) 1154 

Qwwat (90-percentile) 438 

(1) Sample size of 84 companies 

41. Direct and indirect discharges were combined. The EU standard sewage treatment plant with a 

flow rate of 2000 m3.d-1 was used to eliminate from this sample those companies with a higher flow rate. 

84 companies were below this threshold and discharged in total about 15000 m3.d-1. Four very large 

companies that were above this threshold and discharged in total also about 15000 m3.d-1. These four 

companies were eliminated in the evaluation of the 90 percentile. The 90 percentile value is 438 m3.d-1. 

42. It was further assumed that about 3 m3

 water are needed to produce one tonne of rubber goods. 

This water consumption accounts only for the rubber production. 
ENV/JM/MONO(2004)11 

 24

43. With the assumption that the water consumption of the rubber production is 37% of the value for 

the 90-percentile of the wastewater volume, a daily generic production (Qprod) of about 55 tonnes per day is 

derived as the reasonable worst-case generic point source: 

Qprod (generic point source)[t.d-1] = Qwwat (90 percentile) [m3.d-1] * 0.37 / 3 [m3.t-1] 

Qprod (generic point source)[t.d-1] = 438 m3.d-1 * 0.37 / 3 m3.t-1 = 55 t.d-1

44. A further assumption is that the production ratio for tyres: rubber products is 60 : 40. This 

assumption is presented in Table 8. The quantities compiled in this table are also used in example 

calculations (Section 5). 

Table 8 Product Type and Amount produced at the generic Point Source 

Product type 

Amount 

Qprod [kg.d-1] 

Tyres 33000 

tyres total 26400 

 car tyres 11600

 Truck tyres 14800

re-treading 6600 

rubber products 22000

technical tubes, profiles 5320

form products, rubber-metal compounds 5190

glues, mixtures, repair materials 2840

foam-, micro cellular- and cellular rubber products 2110

conveyor belts, flat- and vee belts 1940

sole material 550

sheet material, punching products 460

other technical products 1150

other rubber products 2440

Sum 55000 

Source: Association of the German Rubber Industry (1999) 

4.2 Emission Rate Estimation 

45. The emission scenarios are presented in the following way. 

Input 

[Variable/parameter (unit)] [Symbol] [Unit] [Origin: A/D/O/P]

These parameters are input to the scenario. The A, D, O, or P classification of a parameter indicates the 

status: 

A Parameter must be present in the input data set for the calculation to be executed. The applicant 

delivers it. Normally, there is no default value. 

D Parameter is a standard default value. 

O Parameter is the output from a calculation. 

P Parameter is chosen from a “pick-list” of values. 
 ENV/JM/MONO(2004)11 

 25

Output 

[Symbol] Description 

4.3 Emission Scenario for Formulation and Processing to Wastewater 

46. The following information is needed for the emission calculation of the releases to wastewater: 

• function of the additive (Table 9) 

• product type and amount produced per day [kg/d]. The default values for tyres and different 

rubber products and their sub-divisions are presented in Table 8. 

• additive introduced. This figure is either given in weight percent [wt-%] or in parts per hundred 

rubber [phr]. The latter figure is a special term used in the rubber industry (cf. Table 10). This 

figure can either be delivered by the applicant (A) or can be taken as default (D) from Table 9. 

• fraction of additive remaining in the rubber product. This figure can either be provided by the 

applicant or be taken as default from Table 9. 

47. The emission rate [kg/d] into wastewater is calculated from equation (1) as shown: 

( ) remaining

recipe

additive

water prod F

F

Q Elocal Q ⋅ − ⋅ = ⋅ 1

100 (1) 

Parameter: 

Explanation Symbol Value Unit Origin Remarks 

Input 

Amount of the product type 

produced per day Qprod [kg.d-1] P see Table 8. If no detailed 

information is available the 

default of 55000 kg.d-1 is used 

Parts of additive introduced Qadditive [wt-%] 

or [phr] 

A/P from applicant or Table 9 

Recipe factor Frecipe

2 

resp. 

1 

 A 2, when content is given in phr 

1, when content is given in wt-

% (see Table 10) 

Fraction of additive remaining 

in the rubber product 

Fremaining [-] A/P from applicant or Table 9 

Output

Emission of substance to waste 

water treatment plant 

Elocalwater [kg.d-1] O 

48. Table 9 lists for various additives the content in rubber products and tyres mostly expressed in 

parts per 100 rubber parts [phr]. For worst-case calculations the upper range is used. If the content of the 

additive in the mixture is not specified, then the figure in the overall class (the gray field) can be used. The 

last column presents the fraction of the additive assumed remaining in the rubber product and therefore not 

being subject to emissions during processing. 

49. These figures should not be seen as a possible recipe. The actual amount used depends on the 

function of the mixture and can vary within the ranges given. A tyre for example is composed of 10 
ENV/JM/MONO(2004)11 

 26

different rubber mixtures and is made up of 48 wt-% natural and synthetic rubber, 23 wt-% carbon black, 

18 wt-% steel, 3 wt-% woven glass fabrics and 8 wt-% additives 

[Association of the German Rubber Industry (1999)]. 

Table 9 Functions and Content of Rubber Additives 

Rubber additive Use in rubber products 

[phr] 

Use in tyres 

[phr] 

Fremaining

Mastication agents / peptiser 0.1-0.5 wt-% (NR), 

1-3 wt-% (SR) 

0.5 0.995 

Activator no data 4 

vulcanisation agents 0.25-5 (soft) 

25-40 (hard) 

up to 2 1.0 

sulfur-containing cross-linking agents 2 2 

Vulcanisation accelerator 0.1-2 0.2-2.0 

Accelerator activator 1.5-5 1.3 

sulfur-free cross-linking agents 0.001-1 no data 

coagents for sulfur-free cross-linking 

agents 

0.5-2.0 2.0 

other cross-linking agents 0.001-2.0 0.001-2.0

vulcanisation retarders 1.5-2 0.3-2 

scorch inhibitors 0.1-1 0.5 

anti ageing and antiflex-cracking 

agents / antidegradants

0.8 0.8 0.98 (RP) 

0.99 (TI) 

Antioxidants 0-3 0.25 

Antifatigue agents 1-5 0.2 

Antiozonants 1-7 0.2-1 

light protection agents 0-3 0.2 

anti hydrolysis agents 0.5-3 0,2 

heat protection agents 0.5-3 1 

agents against metal poisoning 0.5-3 0.2 

Deactivators 0.5 0.3 
 ENV/JM/MONO(2004)11 

 27

Rubber additive Use in rubber products 

[phr] 

Use in tyres 

[phr] 

Fremaining

reversion protection agents 0.5-3 no data 

anticyclisation agents 0.5 no data 

Quencher 0.5 no data 

other anti ageing agents 1.5-3.0 no data 

fillers and pigments7 8 Up to 30 up to 40 0.99 

Fillers 10-30 40 

Pigments 1-5 No data 

Plasticiser Up to 20 Up to 3.8 0.959

plasticiser, natural 10-20 2.4-3.8 

plasticiser, synthetic 10-20 2.4-3.8 

Processing aids Up to 15 1-5 0.995 

lubricants and flow improvers 5-15 No data 

Tackifier 5-15 No data 

Factices 5-15 No data 

filler activator 5-15 No data 

blowing agents 5-10 3 0.999 

bonding agents 1-4 3-4 0.999 

Stabiliser 1,5-3 1,5-3 

other agents 0.1-3 0.1-3 0.95 

 

7

 After formulation, fillers are not removed from the rubber matrix. 

8

 Some fillers act as pigments and vice versa. 

9

 Plasticisers do not enter into a chemical bonding with the rubber; migration to the surface is possible. 
ENV/JM/MONO(2004)11 

 28

Rubber additive Use in rubber products 

[phr] 

Use in tyres 

[phr] 

Fremaining

anticyclisation agents No data No data 

replastication agents No data No data 

Emulsifier 0.1-0.5 No data 

flame retardant 2-3 No data 

Solvents No data No data 

surface treatment agent 2-43 2 

Hardeners No data No data 

odour agents 0.25-0.1 No data 

Antistatic agents 0.1-0.6 5 

Microbiocides No data No data 

Antitermite agents No data No data 

Reinforcing agent No data No data 

Homogeniser No data No data 

latex-chemicals Up to 5 0.95(RP) 

dispersion agents 1-2 

Emulsifier 1-5 

Stabilizer 1-2 

wetting and foaming agents 1-2 

foam stabilizers 1-5 

Thickeners No data 

coagulation agents No data 

Preservatives No data 

vulcanisation chemicals 0.5-2 

anti ageing chemicals No data 

Fillers No data 
 ENV/JM/MONO(2004)11 

 29

Rubber additive Use in rubber products 

[phr] 

Use in tyres 

[phr] 

Fremaining

Plasticisers No data 

release agents 10 up to 30 Up to 30 0.95 

for non-vulcanised rubber 0.5-5 0.5-5

mould release agents 5-30 5-30

mandrel release agents 5-30 5-30

Others Up to 5 Up to 5 0.95 

cleaning agents No data No data 

other rubber chemicals No data No data 

TI = tyre industry; RP = rubber products 

50. An example for a recipe is presented to demonstrate the introduction of the Frecipe -factor for 

information about the composition in phr. 

Table 10 Example for a Recipe [Sablowski Datacom 1996] 

Compound constituent Recipe 

[phr] 

Recipe 

[wt-%] 

Synthetic rubber butadiene (SBR) 80.28 43.63 

Butadiene rubber (BR) 19.72 10.72 

fatty acid 1.97 1.07 

Plasticiser 11.97 6.50 

Waxes 1.69 0.92 

zinc oxide 3.10 1.68 

carbon black 60.56 32.91 

anti ageing agent 1.69 0.92 

Accelerator 1.20 0.65 

Sulfur 1.83 0.99 

Sum 184.01 99.99 

 

10 These substances are not a part of the rubber mixture, but will be treated so 
ENV/JM/MONO(2004)11 

 30

4.4 Emission Scenarios for Formulation and Processing to Air and Soil 

51. Hardly any monitoring data for air and soil emissions of rubber additives are available. A simple 

emission scenario based on the A-Tables (emission factors) of the European Union Technical Guidance 

Document (TGD) [EU 2003] from IC-11 (polymer industry) life cycle phase ”polymer use” is presented 

here. For air emissions, the OECD Emission Scenario on “Additives in the Plastics Industry” (Draft July 

2001) may be consulted. 

Table 11 Emission Factors [EU 2003, A-Table for IC-11 “Polymer Industry”) 

Type of additive 

Conditions Emission factor 

Air Fair

 Vapour pressure [Pa] Boiling point [°C] 

Additives 

Pigments 

Colorants 

Fillers 

Processing aids 

< 1 

1-100 

>100 

< 300 / unknown 

> 300 

< 300 / unknown 

> 300 

< 300 / unknown 

> 300 

0.001 

0.0005 

0.0025 

0.001 

0.01 

0.005 

Plasticisers < 400 / unknown 

> 400 

0.01 

0.005 

Vulcanising agents <100 

100-1000 

1000-10000 

>10000 

 0.075 

0.15 

0.25 

0.35 

Soil Fsoil

Additives 

Pigments 

Colorants 

Fillers

 0.0001 

Processing aids 0.0005 

Vulcanising agents 0.0001 

52. The emission rate [kg/d] into air resp. soil is calculated from equation (2) as follows: 

air

recipe

additive

air prod F

F

Q Elocal Q ⋅ ⋅ = ⋅

100 (2) 

Parameter: 
 ENV/JM/MONO(2004)11 

 31

Explanation Symbol Value Unit Origin Remarks 

Input 

Amount of the product type 

produced per day Qprod [kg.d-1] P see Table 8. If no detailed information is available, the 

default 55000 kg.d-1 is used. 

Parts of additive introduced per 

parts of 100 rubber Qadditive

 wt-% 

or [phr] 

A/P from applicant or Table 9 

Recipe factor Frecipe

2 

resp. 

1 

[--] A 2, when content is given in phr 

1, when content is given in wt-

% (see Table 10 Example for 

a Recipe [Sablowski 

Datacom 1996] 

) 

Emission factor to air resp. 

Emission factor to soil 

Fair 

Fsoil

 [--] A/D from applicant or 

Table 11

from applicant or 

Table 11

Output

Emission of additive to air resp.

To soil 

Elocalair 

Elocalsoil

 [kg.d-1] O 

4.5 Emission Scenario for Use of Rubber Products by Tyre Abrasion 

53. Tyres for motor vehicles cause tyre abrasion that is deposited as particles or dust on streets and 

roads and on nearby soil [Baumann and Ismeier 1998, p. 307-353]. These particles are exposed to wind 

transport and weathering so that hydrolysis, leaching, and biodegradation of tyre constituents can take 

place. Photo transformation by light is unlikely to play a major role on degradation. The following 

persistent leaching products were identified, when tyres were kept in water (pH 7) or acid rain water (pH 4) 

for eleven months [Baumann and Ismeier 1998, p. 341] (Table 12). 

Table 12 Laboratory Experiments: long-term Leaching Products of Tyres in distilled and acid rain Water, 

[Baumann and Ismeier 1998, p. 341] 

Substance Abbreviation Concentration [mg/L] 

2-Mercaptobenzothiazol MBT < 0.5 

Benzothiazole BT 15 – 1972 

2-Methylbenzothiazol MeBT < 2 

2-Methylthiobenzothiazol MeSBT < 2 

Aniline 5.9 – 294 

Dicyclohexylamine < 35 – 218 

Cyclohexylamine < 1 – 423 

54. These and other additive substances were identified in monitoring studies of street run-off water 

and urban sediments. These monitoring studies [Baumann and Ismeier 1998; p. 342 - 343; Schmegel 1995, 

p. 75; Spies et al. 1987; Kumata et al. 2000] show that tyre abrasion contributes significantly to run-off 

releases of persistent breakdown products of rubber additives, e.g. benzothiazole and methylated 

benzothiazole. 

55. An approach to calculate the annual regional emission rate [kg/a] of a rubber additive or its 

breakdown product via tyre abrasion is presented in equation (3). 
ENV/JM/MONO(2004)11 

 32

breakdown product

additive

breakdown product ann prod abrasion MW

MW Eregional Q F

_

_ _ = ⋅ ⋅ (3)

Parameter: 

Explanation Symbol Value Unit Origin Remarks 

Input 

Amount of the additive 

produced per year in defined 

region 

Qann _ prod [kg.a-1] A The region needs to be defined. 

Emission factor for abrasion 

from tyres 

Fabrasion 0.12 [--] D Hartung and Koch 1989 p. 33 

Ahlers et al. 1996, p. 73 

Molecular weight of additive MWadditive [g.mol-1] A 

Molecular weight of 

breakdown product 

MWbreakdown_pr

oduct 

 [g.mol-1] A 

Output

Emission rate of breakdown 

product (or additive) from tyre 

abrasion in defined region 

Eregional [kg.a-1] O The quotient of molecular 

weights is one, if the additive is 

considered. 

56. The regional emission rate can be the input parameter in any Mackay level III fugacity model 

(e.g. SimpleBox) for calculating the regional concentrations in surface water and natural soil. 

4.6 Emissions from Leachates 

57. Considerable amounts of used tyres (about 30%) are disposed off in landfills. In Germany this 

amount was 135 000 t.a-1 in 1987 [Hartung and Koch 1989, p.81]. Rubber additives and their breakdown 

products may find their way into leachates of the landfill. Used tyres are used as bumpers in fresh water 

and marine habours. Rubber constituents and breakdown products leach to water. The emission rates of 

such leachate processes are not quantified yet. 
 ENV/JM/MONO(2004)11 

 33

5. EXAMPLES OF EMISSION ESTIMATION 

5.1 Emissions from Formulation and Processing to Wastewater 

A Calculation of the emissions of a plasticiser

Additive in the manufacturing of a tyre; emission occurs during cooling after extrusion (equation 1). 

Input Data 

Qprod = 33000 kg.d-1

Qadditive = 3.8 phr 

Frecipe = 2 - 

Fremaining = 0.95 - 

Output Data 

Elocalwater = 31.35 kg.d-1

B Calculation of the emissions of an antioxidant

Additive in the manufacturing of a rubber product (equation 1). 

Input Data

Qprod = 22000 kg.d-1

Qadditive = 0.4 phr 

Frecipe = 2 - 

Fremaining = 0.99 - 

Output Data 

Elocalwater = 0.4 kg.d-1

C Calculation of the emissions of an anti-ageing agent

Additive in the manufacturing of a truck tyre (equation 1). 

Input Data

Qprod = 14800 kg.d-1

Qaddtivie = 0.5 wt-% 

Frecipe = 1 - 

Fremaining = 0.99 - 

Output Data 

Elocalwater = 0.7 kg.d-1

Example for the determination of the Clocalwater with the data of example B

Additive in the rubber industry. Calculation of PEClocal for the aquatic compartment. The EU default values for the 

waste water treatment plant and the dilution factor are used. Other OECD Member countries may use other default 

values. Site specific values may also be used. 
ENV/JM/MONO(2004)11 

 34

Chemical: Example:

Amount of the product produced per day Qprod = 22000 kg.d-1

(from Table 8): 

Parts of additive introduced in Qadditive = 0.4 phr 

parts of 100 rubber: 

Recipe factor: Frecipe = 2 

Fraction of additive remaining in the product: Fremaining = 0.99 

Fraction of emission directed to water (100% assumed): Fstpwater = 100 % 

(SimpleTreat Model [EU 2003]) 

Capacity of sewage treatment plant (STP) [EU 2003]: EFFLUENTstp = 2000 m3

.d-1

Dilution factor [EU 2003]: DILUTION = 10 

Factor (1+Kp*SUSPwater) [EU 2003]: FACTOR = 1 

Emission per day

recipe

additive remaining

prod F

Q F

Q

∗

∗ − = ∗

100

(1 ) Elocalwater Elocalwater = 0.44 kg.d-1 

Influent concentration

Clocalinf = EFFLUENTstp

Elocal water Clocalinf = 0.22 mg.L-1

Effluent concentration

Clocaleff = Clocalinf * Fstpwater Clocaleff = 220 μg. L-1

Concentration in surface water:

Clocalwater = DILUTION FACTOR

Clocal eff

∗

 Clocalwater = 22 μg. L-1

PEClocalwater = Clocalwater if PECregionalwater = 0 
 ENV/JM/MONO(2004)11 

 35

5.2 Emissions from Formulation and Processing to Air resp. Soil 

A Calculation of the emissions of a plasticiser

Additive in the manufacturing of a tyre; emission occurs during cooling after extrusion (equation 1). 

Input Data

Qprod = 33000 kg.d-1

Qadditive = 3.8 Phr 

Frecipe = 2 - 

Fair = 0.01 - 

Output Data 

Elocalair = 6.27 kg.d-1

5.3 Emission from Abrasion of Tyres 

Example: N-Cyclohexylbenzothiazol-2-sulfenamide (CBS) is degraded to the persistent Benzothiazol 

(BT). Production of this vulcanisation accelerator in Germany is used. 

Input Data

Qann_prod (CBS in 

Germany) 

2030 t.a-1

Fabrasion 0.12

MWbreakdown_product 264.50 g.mol-1

MWadditive 135.18 g.mol-1

Output Data 

Eregionalbreakdown_product 124.5 t.a-1
ENV/JM/MONO(2004)11 

 36

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C (1996). Bewertung der Umweltgefährlichkeit ausgewählter Altstoffe durch das 

Umweltbundesamt. Umweltbundesamt, UBA Texte, Vol.. 38/96. Berlin, p. 373. 

Association of the German Rubber Industry (1990), Wirtschaftsverband der Deutschen Kautschukindustrie 

(WDK). Leaflet of the WDK. 

Association of the German Rubber Industry (1999), Wirtschaftsverband der Deutschen Kautschukindustrie 

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Baumann W and Ismeier M (1998). Kautschuk und Gummi – Daten und Fakten zum Umweltschutz, 

Springer Verlag, Berlin, ISBN 3-540-64044-4. 

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EU (2003). Technical Guidance Document on Risk Assessment, European Commission, Joint Research 

Centre, Ispra/Italy, 2003; http://ecb.jrc.it. 

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Umweltbundesamt, research report UFOPLAN 103 03 220/01. Berlin, p. 117. 

International Rubber Study Group, Rubber Statistics (2003). Rubber Statistical Bulletin, 

http://www.rubberstudy.com - Statistics 

Kumata H, Sanada Y, Takada H, and Ueno T (2000). Historical trends of N-Cyclohexyl-2-

benzothiazolamine, 2-(4-Morpholinyl)benzothiazole, and other anthropogenic contaminants in the 

urban reservoir sediment core, Environ. Sci. Technol. 34, 246-253. 

Lüpfert S (1990). Raw Material in the Rubber Industry in the Light of German and European Legislation, 

Kautschuk, Gummi, Kunststoffe, 43(9), 780. 

Lüpfert S (1991). Environmental Protection versus Compounding, Kautschuk, Gummi, Kunststoffe 44(8), 

771-779. 

OECD (2002). Compilation of comments on the draft emission scenario documents, Document 

TFEEA(2002)2 of 10 June 2002. OECD Paris. 

Rentel KH, Gmehling J, Lehmann E (1991). Stoffbelastung in der Gummiindustrie, Wirtschaftsverlag NW. 

ISBN 3-89429-139-7. 

Sablowski Datacom GmbH (1996). Rubber Doc. 

Schmegel C (1995). Struktur-Wirkungsbeziehungen in der prospektiven Analyse von Umweltgefährdungen 

am Beispiel der Substanzklasse der Benzothiazole. Fachbereich Biologie/Chemie der Universität 

Bremen. PhD dissertation, Bremen, p. 124. 

Spies RB, Andresen BD, Rice DW Jr. (1987). Benzothiazoles in estuarine sediments as indicator of street 

runoff. Nature 327, p. 697-699 

Ullmann’s Encyclopedia of industrial Chemistry (1993), 5th edition, Chapter “Rubber”, Vol. A23, VCH 

Verlag, Weinheim, p. 221-472. 
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7. GLOSSARY 

Adhesion 

The strength of bond between cured rubber surfaces or a cured rubber surface and a non-rubber surface. 

Anticoagulant (Natural Rubber Latex) 

A substance added to field latex to retard bacterial action, which would otherwise cause rapid coagulation 

of the latex. Note: The word "stabilizer" is often used in place of "anticoagulant" in latex terminology. 

Antioxidant 

A chemical used to retard deterioration due to heat, light, oxygen, or combinations thereof. 

Autoclave 

A pressure vessel into which materials or articles can be placed and exposed to steam under pressure. It is 

commonly used for vulcanisation. 

Butyl rubber 

Isobutene-isoprene rubber (IIR), synthetic rubber, soft rubber, chlorobutyl and bromobutyl rubber as 

variants containing halogens with modified properties, high chemical resistance and high resistance to 

permeation, resistant to ozone and weathering 

Calendering 

Calendering is a process in tire manufacturing where steel or fabric is coated with rubber. Steel belts, body 

plies, cap plies and belt edge covers are all produced using the calendering process. Steel or fabric is 

placed between two large heavy rollers. Rubber is also inserted between the rollers at the top and bottom of 

the material being coated. As the material moved through the rollers the pressure forces the rubber to 

permeate and adhere to the steel or fabric.

Compound 

A thorough mixture of natural and/or synthetic rubbers with various ingredients designed for each tire part. 

Curing 

the act of vulcanisation; a description of a definite time and temperature of vulcanisation. 

Emulsifier 

A surface-active substance used to facilitate the dispersion of an immiscible liquid compounding material 

in another liquid and to stabilize the emulsion thereby produced. 

Extrusion 

Extrusion is a process used to manufacture shaped solid rubber. Treads, sidewalls and bead fillers are 

manufactured using extruders. 

Filler 

A solid compounding material, usually in finely divided form, which may be added in relatively large 

proportions to a polymer for technical or economic reasons. 

Mastication 

To dissolve the rubber in solvents a technology was developed which is capable of softening the rubber by 

shearing it between two rotors. 
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Plasticiser 

A compounding material used to enhance the deformability of a polymeric compound. 

Rubber 

Natural rubber or any synthetic, elastomeric material with physical properties similar to those of natural 

rubber. 

Tack 

The ability to adhere to itself; a sticky or adhesive quality. 

Tackifier 

Tackifier resins are processing aids, which help keep rubber components together prior to curing. They are 

especially useful in synthetic rubber compounds, which have low levels of inherent tack. Tackifiers are 

commonly incorporated into solvent base, water-base and hot melt adhesives with a base polymer such as 

natural rubber, styrenic block copolymer, ethylene vinyl acetate, polyethylene homopolymers, and butyl 

elastomers. The optimum type of elastomer will depend upon the final desired application and performance 

properties. 

Thermoplastic Rubber 

Rubber that does not require chemical vulcanisation and will repeatedly soften when heated and stiffen 

when cooled; and which will exhibit only slight loss of its original characteristics. 

Thickener 

A substance used to raise or control the viscosity of latex with out the necessity for major changes in the 

total solids content. 

Vulcanisation 

An irreversible process during which a rubber compound through a change in its chemical structure (for 

example, cross-linking) becomes less plastic and more resistant to swelling by organic liquids and elastic 

properties are conferred, improved, or extended over a greater range of temperature. 
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8. ABBREVIATIONS 

BR butadiene rubber 

CR poly-2-chlorobutadiene 

DIN German Institute for Standardization 

EDTA ethylene diamine tetraacetate 

EPDM ethylene propylene diene rubber 

ESD Emission Scenario Document 

EU European Union 

HF high frequency 

IC industrial category 

IIR isoprene isobutylene rubber 

IR isoprene rubber 

LCM liquid curing method 

Max Maximum 

NBR acrylonitrile butadiene rubber 

NR Natural rubber 

PEClocal Predicted Environmental Concentration at the local stage 

phr parts per hundred rubber 

RP Rubber product 

SBR synthetic butadiene rubber 

SR synthetic rubber 

STP Sewage treatment plant 

TGD Technical Guidance Document of the European Union for Risk Assessment 

Chemicals and Biocides 

TI Tyre industry 

UC use category 

UHF ultra high frequency 

WDK Association of the German Rubber Industry