Development of High Efficient Foam for Refrigerator

using new HFC blowing agents

Kuninari Araki 1) , Kazuto Uekado 2) and Akihide Katata 3)

Representing The JEMA Subsidized Project

1) Hitachi Ltd., 2) Matsushita Refrigeration Co.,

3) The Japan Electrical Manufacturers' Association

ABSTRACT

Since the end of 1993, we have developed High-Efficiency foam of refrigerator for

HCFC-141 b replacement in the subsidized project by MITI (The Agency of Natural

Resources and Energy . Ministry of International Trade and Industry ). Seven major

refrigerator manufacturers in Japan jointed this project and made technical evaluation

steps about urethane foam for refrigerators using next generation blowing agents to

make High-Efficiency foams. The items to be reported are as mentioned below.

(1) Research about next generation blowing agents

(2) Thermal conductivity of new HFCs' panel foam

(3) Cabinet injected test results of new HFCs

1. Introduction

The Japan Electrical Manufacturers ' Association (JEMA) has started the project

subsidized by MITI , for developing next-generation insulation materials to replace

current HCFC blown foam , from December 1993, as a JEMA Subsidized Project with

members from the 7 main refrigerator manufacturers in Japan.

This project is aimed at the establishment of post-HCFC technology that can

suppress the increase of power consumption in household electric refrigerators /

freezers, through the development of next-generation insulation techniques with high

efficiency.

When starting development work, the following conditions of selecting nextgeneration insulation technology were settled:

1) Blowing agents shall have zero ODP and small HGWP.

477

 EE-RM-93-801 COMMENT 289

Development of High Efficient Foam for Refrigerator 

using new HFC blowing agents 

ABSTRACT 

Kuninari Araki 1) , Kazuto Uekado 2) and Akihide Katata 3) 

Representing The JEMA Subsidized Project 

1) Hitachi Ltd., ,2) Matsushita Refrigeration Co., 

3) The Japan Electrical Manufacturers' Association 

Since the end of 1993, we have developed High-Efficiency foam of refrigerator for 

HCFC-141b replacement in the subsidized -project by MITI (The Agency of Natural 

Resources and Energy, Ministry of International Trade and Industry). Seven major 

refrigerator manufacturers in Japan jointed this project and made technical evaluation 

steps about urethane foam for refrigerators using next generation blowing agen~~~t ~,l\.,~. 

make High-Efficiency foams. The Items to be reported are as mentioned below. 

(1) Research about next generation blowing agents 

(2) Thermal conductivity of new HFCs' panel foam 

(3) Cabinet injected test results of new HFCs 

1.lntroductiqn 

The Japan Electrical Manufacturers' Association (JEMA) has started the project 

subsidized by MITI, for developing next-generation insulation materials to replace 

current HCFC blown foam, from December 1993, as a JEMA Subsidized Project with 

members from the 7 main refrigerator manufacturers in Japan. 

This project is aimed at the establishment of post-HCFC technology that can 

suppress the increase of power consumption in household electric refrigerators I 

freezers, through the development of next-generation insulation techniques with high 

efficiency. 

When starti'ng development work, the following conditions of selecting nextgeneration insulation technology were settled: 

1) Blowing agents shall have zero ODP and small HGWP. 

477 
2) Direct and indirect green -house effects shall be small.

3) Thermal-insulation performance of new materials shall be equivalent to or better

than that of the HCFC-141 b urethane foam.

4) Blowing agents shall be safe from toxicity etc. Insulation materials shall be safe

throughout manufacturing , operating and disposal for appliances.

The project organization consists of the JEMA secretariat and the 7 research sublaboratories of the 7 refrigerator manufacturers, that actually carry out practical

development work. A total of about 60 researchers are dispatched from the

manufacturers and registered as concurrent JEMA personnel and are jointly working

for this program.

The 7 refrigerator manufacturers are Sanyo Electric , Sharp, Toshiba,. Hitachi,

Fujitsu-General, Matsushita Refrigeration and Mitsubishi Electric. In addition to these

project members, there are 6 Japanese urethane formulation manufacturers and 4

potential blowing agents suppliers that are supporting the project.

Furthermore, a steering committee is organized with members from academic,

industrial and governmental sectors including public research organizations, and the

committee discusses orientation of R&D and judgment of results , to maintain social

fairness and public benefits as the project Is subsidized by the government.

The project was originally started with a term of 5 years, but has been speeded -up

to a goal of 4 years to cope with rapidly changing environmental conditions such as

earlier restricting HCFC and ruling of new energy standards on household refrigerators

/ freezers in Japan.

2. The present features and status of refrigerators in Japan

At present in Japan, power consumed by electric refrigerators / freezers occupies

about one fourth of the total power consumption in a standard Japanese household.

Fig. 1 shows trends of domestic shipment quantities and volume zones for the latest

about 20 years. The main zone is 350 - 450L, and multi-door refrigerators of 3-

compartments or more, with different temperature ranges are standard . Typically,

478

 EE-RM-93-801 COMMENT 289

2) Direct and indirect green·house effects shall be small. 

3) Thermal·insulation performance of new materials shall be equivalent to or better 

than that of the HCFC·141 b urethane foam. 

4) Blowing agents shall be safe fr~m toxicity etc. Insulation materials shall be safe 

throughout manufacturing, operating and disposal for· appliances. 

The project organization consists of the JEMA secretariat and the 7 research sublaboratories of the 7 refrigerator manufacturers, that actually carry out practical 

development work. A total of about 60 researchers are dispatched from the 

manufacturers and registered as concurrent JEMA personnel and are jointly working 

for this program. 

The 7. refrigerator manufacturers are Sanyo Electric, Sharp, , :~~: .. ;;},,' ,:,~'( ',\:' " '~ 

Fujltsu-General, Matsushita Refrigeration and Mltsublshl Electric. In addition to these . , 

project members, there are 6 Japanese urethane forri1ulation manufacturers and 4 

potential blowing agents suppliers that are supporting the project. 

Furthermore, a steering committee is organized with members from academic, 

industrial and governmental sectors including public research organizations, and the 

committee discusses orientation of R&D and judgment of results, to maintain social 

fairness and public benefits as the project Is subsidized by the government. 

The project was originally started with·a term of 5 years, but has been speeded ·up 

to a goal of 4 years to cope with rapidly changing environmental conditions such as 

earlier restricting HCFC and ruling of new energy standards on household refrigerators 

I freezers in Japan. 

2. The present features and status of refrigerators in Japan 

At present in Japan, power consumed by electric refrigerators I freezers occupies 

about one fourth of the total power consumption in a standard Japanese household. 

Fig. 1 shows trends of domestic shipment quantities and volume zones for the latest 

about 20 years. The main zone is 350 • 450L, and multi·door refrigerators of 3· 

compartments or more, with different temperature ranges are standard. Typically. 

478 
there are frozen foods,

cold storage, vegetable

chamber and icetemperature chc-'

controlled at nearly WC.

Large refrigerators with

5 or 6-do or type are also

used, incorporating

ice-making chamber and

bottle, chamber. Multipreferred InJapan,

door refrigerators are

use Japanese like fresh fishes such as sashimi and snal

fresh foods, so a refrigerator must be delicately temperature-controlled and quickly

cooled. In addition, foodstuff has been diversified and people prefer more of storage

chambers finely sectioned in temperatures. Moreover, Japanese climate is particularly

high-temperature and -humidity, so automatic defrosting system is required.

Therefore, non-frost, fan-cool systems are dominant. Because of limited space for

refrigerators in kitchen in Japanese residential situation, refrigerators with freezing

function are normally used from the old times. Thin wall thickness structures are

preferred using high-performance thermal insulation materials to make effective inner

volume maximum.

Conventionally in Japan , CFC-12 and CFC-11 were used for refrigerators.

Substitutes of these CFC, used now in Japan , include HFC-134a mainly for refrigerant

and HCFC-22 for part of large refrigerators , and as blowing agents, HCFC-141b is

mainly used together with HCFC-22/142b or cyclopentane , joint use of vacuum

Insulation panel and urethane foam.

3. R&D results acquired so far of the project

R&D items so far in the project, besides the examination of urethane insulation

479

 EE-RM-93-801 COMMENT 289

z~. 

thousand 

units 

5aXl 

1Ir::: 

I 

t 

-~ 

Fig.1 PRODUCTION of REFRIGERATORs 

111301L- .1 o 121-3Cn /"":'1\ r--

1111-12Ol ,/ ..... / 

/ ". 

~I I" 

- "-

i'.. " - ,/ -- ...... V i- ,/ 

there are frozen foods, 

cold storage, vegetable 

chamber and icetemperature chamber' 

controlled at nearly O:t. 

large refrigerators with 

5 or Godo or type are also 

used, Incorporating 

4500 

4CXIO 

3SOO 

!XXI 

2500 

2tXXl 

1500 

1 coo 

500 

o 

r 

! ice-making chamber and 

'78 '79 's) '81 '82 '83 '84 '85 '86 '87 '88 '89 '!Il '91 '92 '93 '94 '95 bottle. cham'bar. Multldoor refrigerators are 

,.' '<,' '::<'{:~~~Jii~<;' ";:,y,,~'7' 

preferred In Japan, because Japanese like fresh fishes such as sashlml and seasonali:' , 

fresh foods, so a refrigerator must be delicately temperature-controlled and quickly 

cooled. In addition, foodstuff has been diversified and people prefer more of storage 

chambers- finely sectioned in temperatures. Moreover, Japanese climate is particularly 

high-temperature and ·humidlty, so automatic defrosting system Is required. 

Therefore, non-frost, fan-cool systems are dominant Because of limited space for . 

refrigerators In kitchen In Japanese residential situation,' refrigerators with freezing 

function are normally used from the old times. Thin wall thickness structures are 

preferred using high-performance thermal Insulation materials to make effective Inner 

volume maximum. 

Conventionally in Japan, CFC·12 and CFC·11 were used for refrigerators. 

Substitutes of these CFC, used now in Japan, include HFC·134a mainly for refrigerant 

and HCFC·22 for part of large refrigerators, and as blowing agents, HCFC·141b is . . 

mainly used together with HCFC·221142b or cyclopentane, loint use of vacuum 

insulation panel and urethane foam. 

3. R&D results acquired so far of the project 

R&D items so far in the project, besides the examination of urethane insulation 

479 
technology using new HFCs as a blowing agent, include investigating other chemicals

(HC base blowing agents other than pentane , Fluorolodocarbons etc.) and studying on

vacuum insulation systems. However, the most promising alternative technology has

been focused to the urethane foam Insulation technology using new HFCs from, the

point of view such as Insulation performance, prospective start timing of mass

production before 2000 and economics etc.. Therefore , the development status of

urethane foam technology using new HFCs is reported in the following.

3.1 Thermal conductivity of panel foams using HFC blowing agents

In Fig. 2, typical four types of new HFCs blown foam are compared with HCFC-141 b

2CONDUCTrVITY

of HFCs BLOWN FOAMS

20:0

19.0

18.0

17.0

16.0

15.0

14.0

(mw/m-K)

Mun Temp

0/10/24('C)

Theemal Conductivity at 10'C

17.8

17.3

17.1 6.9

162 16.7

141b(EX) CP(E*) 245b(B) 236ea(X) 356mff 245ea

.and cyclopentane foam;

based on champion Kfactor data of panel foams

tested so far. Mean

temperatures of measurement are 24,10 and VC.

Measuring instrument used

was an auto lambda meter

specified by ASTM C518.

For 241C, an Anacon- Instrument was also used.

Fig. 3 shows all evaluation results tested in 1995, for two types of blowing agents

HFC-236ea and 245fa. The development of optimum insulation materials for

refrigerators was attempted In considering "improvement of thermal insulation

performance," "modifying and optimizing other physical properties ," "advancement of

easy handling at production lines," etc . Practically, high-qualities and cost

effectiveness are most important in addition to the improvement of insulation

properties. Therefore, other factors were also tested and evaluated in the project,

including flowability, viscosity and blending of urethane raw materials , mixing ratios of

480

 EE-RM-93-801 COMMENT 289 .. 

technology using new HFCs as a blowing agent, include investigating other chemicals 

(HC base blowing agents other than pentane, Fluorolodocarbons etc.) and studying on 

vacuum insulation systems. However, the most promising alternative technology has . . 

been focused to the urethan~ foam Insulation technology using new HFCs from- the' 

point of view such as Insulation performance, prospective start timing of mass 

production before 2000 and economics etc.. Therefore, the development status of 

urethane foam technology using new HFCs is reported in the following. 

3.1 Theonal conductivity of panel foams using HFC blowing agents 

In Fig. 2, typical four types of new HFCs blown foam are compared with' HCFC·141 b 

IFlg2 lHERMAL CONDUCITVITY . ofHFCs BLOWN FOAMS . 

lU~~~~-r----r---~---r--~ 

19.0 HOIIIIlIl!.ll"r:l 

18.0 I---+~ 1'-l1----+-~_-f--f 1--1-----1 

11~ I---H:~~+-~~~ 

15.0 

15.0 

14.0 

141b(Ex) CP(EX) 145Ca(B) 236a(X) 356mfr 145ca 

For 24'C, an Anacon- Instrument was also used. 

I 

.and cyclopentane fQal1l~;. , "<_:~~?~f::r:~",>t;'::, 

based· on champlo~·;. K=' 

factor data of panel foams 

tested so far. Mean 

temperatures of measurement are 24,10 and O'C. 

Measuring instrument used 

was an auto lambda meter 

specified by ASTM C518. 

Fig. 3 shows all evaluation results tested In 1995, for two types of blowing agents 

HFC-236ea and 245fa. The development of optimum insulation materials for 

refrigerators was attempted In considering "improvement .of thermal Insulation 

performance," "modifying and optimizing other physical properties," "advancement of 

easy handling at production lines," etc. Practically, high-qualities and cost 

effectiveness are most important in addition to the improvement of insulation 

properties. Therefore, other factors were also tested and evaluated in the project, 

including flowability, viscosity and blending of urethane raw materials, mixing ratios of 

480 

a 
blowing agent and water, optimizing isocyanate, polyol, surfactants, catalyst, etc. The

formulations A, D and Y in Fig. 3 were aimed particularly at high flowability.

Fig.3 THERMAL CONDUCTIVITY

of HFCs BLOWN FOAMS (Panel Data)

20

19

18

17

O E(245fa)

o O(245fa)

o C(245fa)

® B(245fa)

p A(245fa)

16

1s

Panel evaluation items,

other than thermal condIty and flowabil , lnc

lude foam density, cell size,

compression strength, dimensional stability, chemical

compatibility to inner liner,

etc. Compared with the

results for 1994, K-factors

have been ' reduced and

foamed cells have been modified to be more microscopic, along with advancement

toward lower density. However, the authors consider that the data of panel foam are

only referential and comprehensive evaluation shall be given according to the result of

the injected test to be described later, using refrigerator cabinets.

3.2 Evaluation by cabinet injected test

Figs. 4 and 5 show K-factors of urethane foam as a result of cabinet injected tests,

Fig.4 CABINET FOAM TEST

RESULTS USING HFC-236ea

Thermal Conductivity of HFC-236ea foam vs. Current Foam

for blowing agents of HFC236ea and 245fa, respectively.

The sizes of refrigerator

cabinets used for these tests

are classified into 10 types

from 89 to 420L, 2-4 multi

door type. The numbers of

injection holes are 1, 2 or 4.

K-factor were measured with

all samples cut out of cabinets

481

 EE-RM-93-801 COMMENT 289

blowing agent and water, optimizing isocyanate, polyol, surfactants, catalyst, etc. The 

formulations A. 0 and Y In Fig. 3 were aimed particularly at high flowability. 

Fig. 3 THERMAL CONDUCTMTY 

ofHFCs BLOWN FOAMS (panel Data) 

(mW/m·1C) 

20 r-------r---~B~.R~U=U~o~f~23~6= •• ~rC==Ea=4=5~==)~ 

11 I--___ .

BOR uta of 245fa -=..,..,.++-1 C 0(245f.1) 

18 1------1,...-----+-=1 

16 

Ife life 24"'C 

MeanT....rc) 

CC(245f.1) 

"Ba45~) 

OA(245~) 

OY(236.a) 

IIIX(236 •• ) 

Panel evaluation items, 

other than thermal conductMty an~ flowability 9 include foam density, cell size, 

compression strength, dimensional stability, chemical 

compatibility to inner liner, 

etc. Compared with the 

results for 1994, K·factors 

have been· reduced and 

foamed cells have been modified to be more microscopic, along with advancemeni~~;:(<<·~~~)I 

toward lower density. However, the authors consider that the data of panel foam-are 

only referential and comprehensive evaluation shall be given according to the result of 

the injected test to be described later, using refrigerator cabinets. 

3.2 Evaklation by cabinet iniected test 

Figs. 4 and 5 show K·factors of urethane foam as a result of cabinet injected tests, . 

r;:===============================~ for blowing agents of HFC· 

Fig.4 CABINET FOAM TEST 

RESULTS USING HFC-236ea 

Thermal Conductivity ofHFC·236ea foam vs. Current Foam 

x 

y 

481 

236ea and 245fa, respectively. 

The sizes of refrigerator 

cabinets used for these tests 

are classified into 10 types 

from 89 to 420L, 2-4 multi 

door type. The numbers of 

injection holes are 1. 2 or 4. 

K-factor were measured with 

all samples cut out of cabinets 
wall, and mean values were calculated for each blown foam and are compared with

FIg.6 ENERGY CONSUMPTION TEST

RESULTS USING HFC-236ea

at 60Hz

HFC-236ea Foam vs. Current Foam

X/100L(2door)

X/120L(2d*or)

Y/255L(1 door)

(vs 141 b)

80

those of urethane foam using

current blowing agents.

Figs. 6 and 7 show results

of power consumption measurement tests, as compared

with refrigerators using the

current blowing agents.

The boiling points of both

236ea and 245fa are lower than

that of 141b, so the flowability

of foam raw materials becomes

an Important characteristic, on

which the following test results

were obtained.

236ea foam

The boiling point of 236ea is low (6.5t), so the injected mixing materials becomes

froth state. If the degree of frothing is excessively high, the flowability decreased, and

because the shape of mold cavity of refrigerator was complicated, unfilled portions

were left occasionally. Consequently, when using urethane with 236ea, the

temperature reduction of raw material was absolutely necessary to keep flowability.

The results:

New facility that can deal with a low-boiling-point blowing agent must be provided

to produce commercial goods in stabilized conditions.

482

 EE-RM-93-801 COMMENT 289

wall, and mean values were calculated for each blown foam and are compared with 

those of urethane foam using 

Fig.5 CABINETFOAM TEST· 

RESULTS ofHFC-24Sfa 

. lOS eva.14Ib) 

I 

108 eva.141b) 

90 100 

I 

110 120 

00 

Flg.6 ENERGY CONSUMPTION TEST 

RESULTS USING HFC-236ea 

XllOOL(2door) 

114 (vsI4Ib) 

I 

Y/255L(ldoor) ~=~~~?::::;?=(V=S:;22/?:14=2=b)::7j 

90 100 110 120 130 

XlI20L(2door) 

(S) 

236ea foam 

current blowing agents. 

Figs. 6 and 7 show results 

of power consumption meas .. 

urement tests, as compared 

with refrigerators using the 

current blowing agents. 

The boiling points of both 

236ea and 245fa are lower than 

of foam raw materials becomes 

an important characteristic, on 

which the following test results 

were obtained. 

The boiling point of 236ea is low (6.5'C), so the injected mixing materials becomes 

froth state. If the degree of frothing is excessively high, the flowability decreased, and 

because the shape of mold cavity of refrigerator was complicated, unfilled portions 

were left occasionally. Consequently, when using urethane with 236ea, the 

temperature reduction of raw material was absolutely necessary to keep flowability. 

The results: 

• New facility that can deal with a low-boning-point blowing agent must be provided 

to produce commercial goods in stabilized conditions. 

482 
The urethane was charged into a cabinet in a frothed state, so there were many

froth voids in the foam , and K-factors were not satisfactory in considering cell

size. Measured insulation characteristics were lower than expected according to

Fig.7ENERGY CONSUMPTION TEST

RESULTS USING HFC-245fa

HFC-245fa Foam vs. Cunt Foam

A/280U3door)

A/420L(3door)

B/410U4door)

8/120U2door)

C/275U4door)

D/255Utdoor)

E/417U4dood

0 0

WF,

I

103 (v; 141b)

104 (vs 141b)

106 (vs 141b)

105 ( 141b)

(vs CP)

106 (vs 22/142b)

106 (vs 141b)

110 120

I

100

W

the reason why these frothing,

phenomenas are encountered

during charge Into cabinets.

Measured K-factors of urethane foam cut out of injected cabinets were 1.04 to 1.14

times those of current material, and the ratio of power consumption with the new

material to the current one were 1 .04 to 1 .14 times as large.

245fa foam

The boiling point of the 245fa is 15.30C, and its handling was revealed to be better

than 236ea according to the result of cabinet injection.

40 The chargeability of 245fa urethane was comparatively good . Violent frothing

phenomena when injecting could be prevented by lowering the temperature of the

raw material to 10 to 1590. The possibility of using the current facility for mass

producing refrigerators with 245fa was confirmed by lowering the temperature of

raw material, although chargeability will be slightly lower than the current

material.

As the temperature of raw material was set lower, reaction was slower and

chargeability and cureabiiity were adversely affected.

Problems to be solved in the future include compromising of reaction and

cureabiiity and how to reduce voids.

483

 EE-RM-93-801 COMMENT 289

• The urethane was charged Into a cabinet In a frothed state, so there were many 

froth voids in the foam, and K·factors were not satisfactory in considering cell 

size. Measured insulation characteristics were lower than expected according to 

A/420L(3door) 1===*== •• 

Bll2OLC2door) 

Bl410L(4door) I; ~::=::;:~:~:s 

the reason why these frothln~ 

phenomenas are encountered 

during charge Into cabinets. 

• Measured K-factors of urethane foam cut out of Injected cabinets were 1.04 to 1.14 

times those of current material, and the ratio of power consumption with the new 

material to the current one were 1.04 to 1.14 times as large. 

245fafoam 

The boiling point of the 245fa is 15.3'C, and its handling was revealed to be better 

than 236ea according to the result of cabinet injection. 

• The chargeability of 245fa urethane was comparatively good. Violent frothing 

phenomena when injecting could be prevented by lowering the temperature of the 

raw material to 10 to 15'C. The possibility of using the current facility for mass 

producing refrigerators with 245fa was confirmed by lowering the temperature of 

raw material, although chargeability will be slightly lower than the current 

material. 

• As the temperature of raw material was set lower, reaction was slower and 

chargeability and cureability were adversely affected. 

• Problems to be solved in the future include compromising of reaction and 

cureability and how to reduce voids. 

483 
Measured K-factors of urethane foam of disassembled refrigerators were 0.97 to

1.06 times the current materials, and the ratios of power consumption were 0.97 to

1.06 times as large.

Some cabinets were tested by charging through one injection hole on the bottom.

"W type formulation wasa s devised to Improve flowability of the raw materials to

assure satisfactory chargeability. According to the test result of this type

cabinets, froth voids could be suppressed, and foam could be more uniform. By

this effect, power consumption of the refrigerator using "A" blown foam was

more than expected from the data of panel foam.

In 1996 s research, further improvements are being Introduced, based on the above

results. We are convinced that considerable Improvement result can be expected.

3.3 Coen tibility of HFCs with ABS Inner liner

The degrees of chemical-attack aggressiveness by blowing agents to the inner

liner material ABS are ranked as follows.

CFC-11 < HFC-245fa < HFC-236ea < HCFC - 141b aggressive

Further long-term reliability tests will be required from now, but we already have a

verification that a low-cost material cheaper than that for HCFC-141 b can be introduced.

3.4 Evaluation of the physical characteristics of new HFCs

In cooperation with public research organizations and universities , the project has

been conducting various experiments including the estimate of HGWP, toxicity tests,

gas phase thermal conductivity of blowing agent candidates.

Fig. 8 shows the status of toxicity tests based on The Chemical Substance Control

Law of Japan, so far carried out for new candidates . We would be pleased if these test

data could somewhat complement an application data for a fluorine chemical

manufacturer when it applies a sub-stance according to the Law.

484

 EE-RM-93-801 COMMENT 289

• Measured K-factors of urethane foam of disassembled refrigerators were 0.97 to 

1.06 times the current materials, and the ratios of power consumption were 0.97 to 

1.06 times as large. 

• Some cabinets were tested by charging through one injection hole on the bottom. 

"AlB type formulation was devised to Improve flowabillty of the raw materials to 

auu ... satisfactory chargeablllty. According to the test result of this type 

cabinets, froth voids could be suppressed, and foa~ could be more uniform. By 

this effect, power consumption of the refrigerator usinguA" blown foam was 

more than expected from the data of panel foam. 

In 1996's research, further improvements are being Introduced, based on the above 

results. We are convinced that considerable Improvement result can be expected. 

3.3 ComPatibility of H.-Cs with ABS inner liner 

The degrees of chemical-attack aggressiveness by blowing agents to the inner 

liner material ABS are ranked as follows. 

CFC-11 < HFC-245fa < HFC-236ea < HCFC -141b - aggressive 

Further long-term reliability tests will be required from now, but we already have a 

verification that a low-cost material cheaper than that for HCFC-141 b can be introduced. 

3.4 Evaluation of the physical characteristics of new HFCs 

In cooperation with public research organizations and universities, the project has 

been conducting various experiments including the estimate of HGWP, toxicity tests,· 

gas phase thermal conductivity of blowing agent candidates. 

Fig. 8 shows the status of toxicity tests based on The Chemical Substance Control 

Law of Japan, so far carried out for new candidates. We would be pleased if these test 

data could somewhat complement an application data for a fluorine chemical 

manufacturer when it applies a sub-stance according to the Law. 

484 

I 
Gas phase thermal conductivitiy of new blowing agents, were measured in Kobe

Fig.8 TOXICITY TEST

(For The Chemical Substance Control Law)

Reverse-Mutatiort

Assay in Bacteria

chromosomal

Aberration Test

28-days Repeated

Dose Toxicity Test

in Mammalian Species

Biodegradetion Test

Bioaccunnulation Test

C•245fa 23 6ca

245ca 365mfc FIC'

HTC•245fa 236ea

245ca 365mfe

no plan to test in JEMA _ ..

no plan to test in JEMA

no plan to test in JEMAA

Application for

Assessment of

Chemical

Substance

Control Law

according to these results.

4. Conclusions

The above results are summarized as follows.

University.

Thermal conductivitiy of

HFC gases are normally

higher than those of

CFC and HCFC gases.

However, K-factors of

urethane foam are approaching those of the

141b blown 'foam, more

closely than expected

(1) As long as the R&D results obtained so far are concerned, the best insulation

performance relates to the foam based on HFC-245fa. We expect that more

improvement of Insulation characteristics for refrigerators could be conducted by

modifying formuration.

(2) Although the boiling point of HFC-245fa Is lower than 141 b, the current foaming

equipment for refrigerators may also be applicable to the agent without substantial

modifications, for mass production of refrigerators.

(3) The use of 236ea or 245fa as a blowing agent, will not raise particular problems

provided the ABS inner liner materials Is optimized.

(4) There are no major problems in the process of evaluating basic physical

characteristics of new HFCs as a blowing agent.

(5) The insulation technology using new HFC blowing agents may become more

Important In the near future , as one of the options for energy conservation with

electric refrigerators i freezers.

485

 EE-RM-93-801 COMMENT 289

- Gas phase thermal conductivitiy of new blowing agents, were measured in Kobe 

, 

Fig.S TOXICITY TEST 

(For The Chemical Substance Control Law) 

I ~MutIWcm I HFC·24sra 236ea 

A£ay in Bacteria 24Sca 36SmCc FIC'~ 

I Chromosomal I HFC·24SCa 236ea : Abemtion Test 24Sca 36SmCc ..... ~ Application for 

2Uays Repeated . . Assessment of 

Dose Toxicity Test no plan to tes~ in JEMA : . ............................. Chemical 

in Mammalian Species 

no plan to test in JEMA : 

Substance 

I B iodegradetion Test I· .......... ·· .... ··· .. ····~ Control Law 

. no plan to test in JEMA: I Bioaccunnulation Test t .. ······· .. ·········· .. ·· ~ 

according to these results. 

4. Conclusions 

The above results are summarized as follows. 

University. 

Thermal conductivitiy of 

HFC gases are normally 

higher than those of 

CFC and HCFC gases. 

However, K·factors of 

urethane foam are approaching those of the 

141 b blown 'foam, more 

closely than expected 

(1) As long as the R&D results obtained so far are concerned, the best Insulation 

performance relates to the foam based on HFC-245fa. We expect that more 

Improvement of Insulation characteristics for refrigerators could be conducted by 

modifying formuration. 

(2) Although the boiling point of HFC-245fa Is lower than 141b, the current foaming 

equipment for refrigerators may also be applicable to the agent without substantial 

modifications, for mass production of refrigerators. 

(3) The use of 236ea or 245fa as a blowing agent, will not raise particular problems 

provided the ASS inner liner materials is optimized. 

(4) There are no major problems in the process of evaluating basic physical 

characteristics of new HFCs as a blowing agent. 

(5) The insulation technology using new HFC blowing agents may become more 

important in the near future, as one of the options for energy conservation with 

electric refrigerators I freezers. 

485 
5. View to the future

The project subsidized by MITI for developing HCFC-free, high-performance

insulation technology for refrigerators, started from 1993, will be finished at the end of

March 1997, and after that, the industry will continue developing toward the practical

goal without a governmental subsidy.

Among the development results obtained in 1996 's research, successful

improvements other than those presented above are acknowledged.

We would like to continue exchanging technical Information with AHAM and ITAC

also in the future, and to lead the new HFC blowing technology, currently one of the

most hopeful substitute technologies, to an established mass-production technology.

We also ;wish that related industrial associations such as construction fields will also

consider to practically apply this technology.

486

 EE-RM-93-801 COMMENT 289

5. View to the futur! 

The project subsidized by MITI for developing HCFC-free, high-performance 

insulation technology for refrigerators, started from 1993, will be finished at the end of 

March 1997. and after that, the industry will continue developing toward the practical 

goal without a governmental subsidy. 

Among the development results obtained in 1996's research, successful 

improvements other than those presented above are acknowledged. 

We would like to continue exchanging technical information with AHAM and ITAC 

also in the future, and to lead the new HFC blowing technology. currently one of the 

most hopeful substitute technologies, to an established mass-production technology. 

We also ,wish that related industrial associations such as construction fields will also 

.,< 

consider to practically apply this technology. 

486 

Q