HFC-236ea and HFC-245fa as HCFC-141 b

Replacement Blowing Agent

Michihiko Suzuki

Chemicals General Division, Asahi Glass Co., Ltd.

2-1-2,Marunouchi,Chiyoda-ku

Tokyo 100, Japan

and

Hiromitu Takeyasu, Minako Aoyagi

Functional Products R&D Center, Asahi Glass Co., Ltd.

3-474-2 Tsukakoshi, Saiwaiku, Kawasaki-shi

Kanagawa-ken 210, Japan

Abstract

CFC-11 had been used as an excellent and sole blowing agent of polyurethane foam

for household refrigerator insulation material till phase out of CFC in Japan. We have

received instruction from Ministry of International Trade and Industry (MITI) of Japan to

stop the production of HCFC-141 b, which is the predominant blown agent used now, by

the end of 2004.

Therefore, a new blowing agent will be necessary to be developed which has zero

ozone depletion potential (ODP) and low thermal conductivity. It will be also necessary

to set up new formulation of polyurethane foam to evaluate the forming conditions and

the physical properties of foam.

Results of experiments showed that HFC-245fa and HFC-236ea almost satisfied the

forming conditions and the physical properties as blowing agents to replace HCFC-1 41 b.

HFC-245fa blown foam has slightly better properties than HFC-236ea blow foam.

In next experiments, for the purpose of substituting HFC-245fa for HCFC-141 b, we

will have to develop the best formulation for HFC-245fa so as to perfectly satisfy

polyurethane foam properties such as thermal conductivity. Preliminary toxicity study

of HFC-245fa did not show any significant adverse effected and additional studies are

progressing.

487

 EE-RM-93-801 COMMENT 290

HFC-236ea and HFC-245fa as HCFC-141 b 

Replacement Blowing Agent 

Abstract 

Mlchlhlko Suzuki 

Chemicals General Division, Asahi Glass Co., L~d. 

2-1-2,Marunouchi,Chiyoda-ku 

Tokyo 100, Japan 

and 

Hlromitu Takeyasu, Minako Aoyagi 

Functional Products R&D Center, Asahi Glass Co., Ltd. 

3-474-2 Tsukakoshi, Saiwaiku, Kawasaki-shi 

Kanagawa-ken 210, Japan 

CFC-11 had been used as an excellent and sole blowing agent of polyurethane foam 

for household refrigerator insulation material till phase out of CFC in Japan. We have 

received instruction from Ministry of International Trade and Industry (MITI) of Japan to 

stop the production of HCFC-141 b, which is the predominant blown agent used now, by 

the end of 2004. 

Therefore, a new blowing agent will be necessary to be developed which has zero 

ozone depletion potential (ODP) and low thermal conductiVity. It will be also necessary 

to set up new formulation of polyurethane foam to evaluate the forming conditions and 

the physical properties of foam. 

Results of experiments showed that HFC-245fa and HFC-236ea almost satisfied the 

forming conditions and the physical properties as blowing agents to replace HCFC-141 b. 

HFC-245fa blown foam has slightly better properties than HFC-236ea blow foam. 

In next experiments, for the purpose of substituting HFC-245fa for HCFC-141 b, we 

will have to develop the best formulation for HFC-245fa so as to perfectly satisfy 

polyurethane foam properties such as thermal conductivity. Preliminary toxicity study 

of HFC-245fa did not show any significant adverse effected and additional studies are 

progressing. 

487 
1.introduction

Asahi Glass is the only company to manufacture both fluorocarbons and

polyurethanes in Japan, and is developing new formulations for household refrigerator

insulation foams as good as those using CFC-11 or HCFC-141b. It is a member of

Japan Fluorocarbon Manufactures Association (JFMA), and has been attending the

subsidized project for development of high efficient foam appliance carried out by the

Japan Electrical Manufacturers' Association (JEMA) to develop new formulations of

polyurethane insulation foam since 1993. 1), 2)

At present, in Japan HCFC-141b is mainly used as a blowing agent of household

refrigerator polyurethane foam. In order to phase out HCFC-141 b by the end of 2004,

fluorocarbon and polyurethane manufacturers have to develop new insulation materials

in cooperation with household refrigerator manufacturers.

2.Objectlve

Followings are requirements of blowing agents and polyurethane foam :

(1)Blowing agent

© Zero ozone depletion potential (ODP)

02 Low thermal conductivity

O Suitable boiling point(10--40`C)

® Non flammable

(5 Low toxicity

© Good solubility in polyols

(2)Polyurethane foam

10 Low thermal conductivity (K-factor as same as HCFC-141 b)

20 Safety (non flammable)

30 Dimension and K-factor Stability

3.Selection criteria

For the selection of candidate blowing agents many factors must be considered such

as environmental property, moldability and physical properties of foam, ease of

manufacture, and cost.

Table 1 and table 2 show some potential blowing agents of polyurethane compared

with CFC-11 and HCFC-141b. At first, we chose the blowing agents which are non

flammable and of low thermal conductivity, and started experiments to mold polyurethane

foam using HFC-245fa or HFC-236ea which has practical thermal conductivity and non

flammability.

488

 EE-RM-93-801 COMMENT 290

I,,'i' 'II' 

1.1ntroductlon 

Asahi Glass is the only company to manufacture both fluorocarbons and 

polyurethanes in Japan, and is developing new formulations for household refrigerator 

insulation foams as good as those using CFC-11 or HCFC-141 b. It is a member of 

Japan Fluorocarbon Manufactures Association (JFMA), and has been attending the 

subsidized project for development of high efficient foam appliance carried out by the 

Japan Electrical Manufacturers' Association (JEMA) to develop new formulations of 

polyurethane insulation foam since 1993. 1), 2) 

At present, in Japan HCFC-141 b is mainly used as a blowing agent of household 

refrigerator polyurethane foam. In order to phase out HCFC-141 b by the end of 2004, 

fluorocarbon and polyurethane manufacturers have to develop new insulation materials 

in cooperation with household refrigerator manufacturers. 

2.0blectlve 

Followings are requirements of blowing agents and polyurethane foam : 

(1)Blowing agent 

<D Zero ozone depletion potential (ODP) 

® Low thermal conductivity 

@Suitable boiling point(10 ...... 40'C) 

@ Non flammable 

@ Low toxicity 

@ Good solubility in polyols 

(2)Polyurethane foam 

CD Low thermal conductivity (K-factor as same as HCFC-141 b) 

® Safety (non flammable) 

@ Dimension and K-factor Stability 

3.Selectlon criteria 

For the selection of candidate blowing agents many factors must be considered such 

as environmental property, moldability and physical properties of foam, ease of 

manufacture, and cost. 

Table 1 and table 2 show some potential blowing agents of polyurethane compared 

with CFC-11 and HCFC-141 b. At first, we chose the blowing agents which are non 

flammable and of low thermal conductivity, and started experiments to mold polyurethane 

foam using HFC-24Sfa or HFC-236ea which has practical thermal conductivity and non 

flammability. 

488 
has a serious flammability problem and VOC restrictions in some countries. HFC-134a

and water, which have good environmental properties , can not satisfy either boiling point

or low thermal conductivity.

Table 1. Environmental pro perties of blowing agents

blowing agent ODP phase out flammability toxicity

CFC-11 1.0 1995 non good

HCFC-1 41 b 0.11 2004 9.0-15.4% in air* good

HFC-245fa non no adverse finding

(testing in progress)

HFC-236ea 0 non no adverse finding

(testing in progress)

HFC-134a non good

cyclopentane 0 1.1 -8.7% in air* not clear

water (CO2) non good

* J. M. Calm,Refrigerant database version 1.23, Air-Conditioning and Refrigeration

Technology Institute, 1996.

blowing agent chemical formula molecular weight boiling point

°C

thermal conductivity

kcal/mhrrsolubility

CFC-11 CCI3F 137 24 0.0140 good

HCFC-141b CH3CCI2F2 117 32 0.0151 good

HFC-245fa CHF2CH2CF3 134 15.3 0.0169 good

HFC-236ea CF3CHFCHF2 152 6.5 0.0173 good

HFC-134a CF3CH2F 102 -26 0.0220 bad

c clo entane C5H,o 70 49.5 0.0171 good

water H2O(_CO2) 18 100 0.0220 bad

4. Evaluation

Asahi glass usually evaluates polyurethane formulation by three molding methods:

hand mix, low pressure machine molding and high pressure machine molding. High

pressure machine molding is the method used in production line by household

refrigerator manufactures. Hand mix requires small quantity of material and is suitable

to conduct preliminary formulation testing. Low pressure machine molds similar foam

to that by high pressure machine but requires less material.

Table 2 Physical properties of blowing a ents

489

 EE-RM-93-801 COMMENT 290

has a serious flammability problem and vac restrictions in some countries. HFC-134a 

and water, which have good environmental properties, can not satisfy either bOiling point 

or low thermal conductivity. 

11 a bl e 1 E nVlronmenta properties 0 fbi oWing agents 

blowing agent OOP phase out flammability toxicity 

CFC-11 1.0 1995 non good 

HCFC-141b 0.11 2004 9.0 ...... 15.4% in air* good 

HFC-245fa 0 - non no adverse finding 

(testing in progress) 

HFC-236ea 0 - non no adverse finding 

(testing in progress) 

HFC-134a 0 - non good 

cyclopentane 0 - 1.1-8.7% in air* not clear 

water (CO2) 0 - non good CbS, ' 

"" "./;bc2 <'r :-

* J.M.Calm,Refrigerant database version 1.23, Air-Conditioning and Refrigeration 

Technology Institute, 1996. 

To a e bl 2 Ph lyslca . I . prope rf les 0 fbi oWing agents 

blowing agent chemical formula molecular weight boiling point thermal conductivity solubility 

"C kcal/mhr'C 

CFC-11 CCbF 137 24 0.0140 good 

HCFC-141b CH3CCI2F2 117 32 0.0151 good 

HFC-245fa CHF2CH2CF3 134 15.3 0.0169 good 

HFC-236ea CF3CHFCHF2 152 6.5 0.0173 good 

HFC-134a CF3CH2F 102 -26 0.0220 bad 

cyclopentane CSH10 70 49.5 0.0171 good 

water H2O(-C02) 18 100 0.0220 bad 

4.Evaiuation 

Asahi glass usually evaluates polyurethane formulation by three molding methods: 

hand mix, low pressure machine molding and high pressure machine molding. High 

pressure machine molding is the method used in production line by household 

refrigerator manufactures. Hand mix requires small quantity of material and is suitable 

to conduct preliminary formulation testing. Low pressure machine molds similar foam 

to that by high pressure machine but requires less material. 

489 

. 
to conduct preliminary formulation testing . Low pressure machine molds similar foam

to that by high pressure machine but requires less material.

Figure 1 shows schematic diagram of machine molding system of polyurethane.

HFC is dissolved in polyol premix to make polyol system before molding.

Figure 1 Low and high pressure machine molding

Table 3 shows the basic formulation selected by hand mixing . • Equimolar quantities

of three blowing agents were used in each formulation.

blowing a ent HCFC-141b HFC-245fa HFC-236ea

unit pbw pbw pbw

polyol premix

polyol

water

additives *

100

0.5.

4.9

100

0.5

5.2

100

0.5

4.1

blowing agent 36 44 43

isocyanate 150 161 146

* silicone surfactant, amine catalyst, etc.

Table 3 HFC and polyurethane formulation

490

 EE-RM-93-801 COMMENT 290

'111111111 .' 

to conduct preliminary formulation testing. Low pressure machine molds similar foam 

to that by high pressure machine but requires less material. 

Figure 1 shows schematic diagram of machine molding system of polyurethane. 

HFC is dissolved in polyol premix to make polyol system before molding . 

..--

Mixing Head 

Test Mold 

Figure 1 Low and high pressure machine molding 

. Table 3 shows the basic formulation selected by hand mixing .. Equimolar quantities 

of three blowing agents were used in each formulation. 

Ti a bl e 3 HFC anpOIyure d th ane f ormu If a Ion 

blowinq aqent HCFC-141b HFC-245fa HFC-236ea 

unit pbw pbw pbw 

polyol premix 

polyol 100 100 100 

water 0.5 0.5 , 0.5 

additives * 4.9 5.2 4.1 

blowing agent 36 44 43 

isocyanate 150 161 146 

* silicone surfactant, amine catalyst, etc. 

490 
Table 4 shows molding conditions. Hand mixing takes longer time to complete

reaction than machine molding but major foam properties of the. resulting foam are

similar among three methods.

molding meth hand mixing low pressure machine high pressure machine

component temp. (`C) 10 5-10 10^-20

machine out-put (kg/mm)n - 14 60

out-put pressure (kg/cm 2 - 24 120

blowing agent 245fa 236ea 245fa 236ea 245fa 236ea

free-blow foaming

cream time

gel time

tack free time

(sec)

sec

froth

50

52

froth

61

70

froth

33

35

froth

42

44

froth

30

35

froth

39

42

core foam densi k /m3 29.6 29.6 28.5 28.3 28.3 29.9

5.Results

Table 5 shows that HFC-245fa blown foam has slightly, better properties HFC-236ea

blown foam.

machine type low pressure hi h pressure

blowing agent 245fa 236ea 245fa 236ea -

overall density (kg

/M3) 35. 6 37.9 34.7 39.8

core density (kg

/M3) 30.4 34.4 29.5 36.0

K-factor* 24C (kcal/mh°C)

(mW/mK)

0.0135

15.7

0. 0137

16. 0

0.0133

15.5

0.0136

15.9

-

comp ressive strength k /cm2 1.60 1.44 1.21 1.48

dimensional stability

-20rX24h (%)

70rX24h %

-0.2

0.7

-0.3

0.4

-0.5

1.0

-0.7

0.6.

* Measured by Anacon model 88

Table 6 shows that HFC-245fa blown foam by high pressure machine has similar

core density to that of HCFC- 141 b blown foam, while HFC - 236ea blown foam has larger

core density.

Table 5 Properties of HFC-245fa and 236ea blown foam (test mold

Table 4 Molding conditions and characteristics

491

 EE-RM-93-801 COMMENT 290

Table 4 shows molding conditions. Hand mixing takes longer time to complete 

reaction than machine molding but major foam properties of the' resulting foam are 

similar among three methods. 

't a e 4 bl Mid' o mg con d" Itlons an d h c aractenstlcs 

molding. method hand mixing low pressure machine hiah pressure machine 

component temp. ("C) 10 5 ...... 10 10 ...... 20 

machine out-put (kg/min) - 14 60 

out-put pressure (kg/cm2

) - 2-4 120 

blowing_ agent 245fa 236ea 245fa 236ea 245fa 236ea 

free-blow foaming 

cream time froth froth froth froth froth froth 

gel time (sec) 50 61 33 42 30 39 

tack free time (sec) 52 70 35 44 35 42 

core foam density (kg/m3

) 29.6 29.6 28.5 28.3 28.3 29.9 

S.Results 

Table 5 shows that HFC-245fa blown foam has slightly better properties HFC-236ea 

blown foam. 

Table 5 Properties of HFC-245fa and 236ea blown foam (test mold) 

machine type low pressure _ high pressure 

blowing agent 245fa 236ea 245fa 236ea 

overall density (kg/m3

) 35.6 37.9 34.7 39.8 

core density (kg/m3

) 30.4 34.4 29.5 36.0 

K-factor* 24 'C (kcal/mh'C) 0.0135 0.0137 0.0133 0.0136 

(mW/mK) 15.7 16.0 15.5 15.9 

compressive strength (kg/cm2

) 1.60 1.44 1.21 1.48 

dimensional stability 

-20'CX24h (%) -0.2 -0.3 -0.5 -0.7 

70'CX24h (%) 0.7 0.4 1.0 0.6. 

* Measured by Anacon model 88 

Table 6 shows that HFC-245fa blown foam by high pressure machine has similar 

core density to that of HCFC-141 b blown foam, while HFC-236ea blown foam has larger 

core density. 

491 

1 
III

property b HFC-245fa HFC-236ea

free-blow foaming

cream time (sec) 7-8 froth froth

gel time (sec) 38-40 30 39,

tack free time (sec) 41^-42 35 42

core foam densi (sec) 25.4-25.5 28.3 29.9

panel foaming

overall density (kg/m3) 38.0^'38.1 34.7 39.8

core density (kg/m') 30.9-31.2 29.5 36.0

K-factor* 24C (kcal/mh`C) 0.0127-0.0130 0.0133 0.0136

(mW/mK) 14.8^-15.2 15.5 15.9

compressive strength k /cm2 1.05^--1.06 1.21 1.48

dimensional stability

-20tX24h (%) -0.7 ---0.8 -0.5 -d 7__......_

701;X24h % 0.8^-1.2 11.0 0.6

cell size (u m) 200-220 210-240 210^-240

*Measured by Anacon model 88

Figure 2 shows that the K-factor varies depending on temperature. The

polyurethane foam for household refrigerator is used at about 50C and thus it is

important to measure K-factor at lower temperature. Figure 2 also shows that the

thermal conductivities of the polyurethane foam blown by HFC-245fa and HFC-236ea are

comparable to that by HCFC-141 b.

20

E

19

18 -•- HCF-141 b

°°^-- HFC-245fa

-^-- HFC-236ea

16 ' I _1

Table 6 Properties of high ressure machine made foam (test mold

-10 0 10 24 30

temperature C

Figure 2 Relationship between thermal conductivity and temperature

(Measured by Eikoseiki HC-073)

492

 EE-RM-93-801 COMMENT 290

Table 6 Properties of high pressure machine made foam (test mold) 

property HCFC-141b HFC-245fa HFC-236ea 

free.,.blow foaming 

cream time (sec) 7-8 froth froth 

gel time (sec) 38-40 30 ,39, 

tack free time (sec) 41-42 35 ~2 

core foam densi!Y (sec) 25.4-25.5 28.3 29.9 

panel foaming 

overall density (kg/m3

) 38.0-38.1 34.7 39.8 

core density (kg/m3

) 30.9--31.2 29.S 36.0 

K-factor* 24 "C (kcallmh'C) 0.0127----0.0130 0.0133 0.0136 

(mW/mK) 14.8-1S.2 15.5 1S.9 

compressive strength (kg/cm2

) 1.0S-1.06 1.21 1.48 

dimensional stability 

-20'CX24h (%) -0] ....... -0.8 -0.5 .:~~~;i'·, .- I, 70'CX24h (%) 0.8 ....... 1.2 1.0 

cell size (/1. m) 200 ....... 220 210--240 210~240 

*Measured by Anacon model 88 

Figure 2 shows that the K-factor varies depending on temperature. The 

polyurethane foam for household refrigerator is used at about 5"C, and thus it is 

important to measure K-factor at lower temperature. Figure 2 also shows that the 

thermal conductivities of the polyurethane foam blown by HFC-24Sfa and HFC-236ea are 

comparable to that by HCFC-141 b. 

~ 

E 

-;: 

E 

I0 

-(.) 

~ I 

~ 

20 

19 

18 ------ HCF-141 b 

-HFC-245fa 

17 ....-HFC-236ea 

16 

-10 o 10 24 30 

temperature 'C 

Figure 2 Relationship between thermal conductivity and temperature 

(Measured by Eikoseiki HC-073) 

492 
6.Conclutlons

(1)New formulations for HFC-245fa and HFC-236ea were developed to enable low Kfactor comparable to that with HCFC-141 b. HFC-245fa has slightly better properties

than HFC-236ea blown foam.

(2)HFC-245fa will be able to replace HCFC-1 41 b by further development of polyurethane

formulation to improve thermal conductivity.

References

1) Sachio Otoshi, The 2nd JEMA/ITAC joint meeting, May 23 ,1995

2) Sachio Otoshi, The 3rd JEMA/ITAC joint meeting, May 24 ,1996

493

 EE-RM-93-801 COMMENT 290

6.Conclutlons 

. (1)New formulations for HFC-245fa and HFC-236ea were developed to enable low Kfactor comparable to that with HCFC-141 b. HFC-245fa has slightly better properties 

than HFC-236ea blown foam. 

(2) HFC-245fa will be able to replace HCFC-141 b by further development of polyurethane 

formulation to improve thermal conductivity. 

References 

1) Sachio Otoshi, The 2nd JEMNITAC joint meeting, May 23 ,1995 

2) Sachio Otoshi, The 3rd JEMNITAC joint meeting, May 24 ,1996 

.'. 

493