# 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 

# 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 polyurethanefoam 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-141b, 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 lowthermal conductiVity. Itwill 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.

4871.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 

### 'II' I,,'i' 

### 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-141b is mainly used as a blowing agent of household refrigerator polyurethane foam. In order to phase out HCFC-141b 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-141b) 

## ® Safety (non flammable) @ Dimension and K-factor Stability



### 3.Selectlon criteria Forthe selection of candidate blowing agents manyfactors 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 lowthermal conductivity, and started experiments to mold polyurethane foam using HFC-24Sfa or HFC-236ea which has practical thermal conductivity and non flammability.



### 488has 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 properties 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 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.

a e 11 bl 1 EnVlronmenta properties 0fbioWing 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 bl 2 Ph . I rf

a e lyslca

.prope les 0fbioWing agents blowing agent chemical formula molecularweight 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 '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.

a e anpOIyure 

### Ti bl 3 HFC d thane f If ormu 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.

490Table 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

- compressive 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 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 bl

a e 4 o mg con Itlons an Mid' 

### d" 

### 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 slightlybetter 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-141b blown foam, while HFC-236ea blown foam has larger core density.

491 

# 1III 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

1 16 ' I _ 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 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 ofthe polyurethanefoam blown by HFC-24Sfa and HFC-236ea are comparable to that by HCFC-141b.**~** 

### 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)

4926.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 

### 6.Conclutlons . (1)New formulations for HFC-245fa and HFC-236ea were developed to enable low Kfactor comparable to that with HCFC-141b. HFC-245fa has slightly better properties than HFC-236ea blown foam. (2)HFC-245fawill be able to replace HCFC-141b byfurther development ofpolyurethane formulation to improve thermal conductivity.



### References

1) Sachio Otoshi, The 2nd JEMNITACjoint meeting, May 23 ,1995 2) Sachio Otoshi, The 3rd JEMNITACjoint meeting, May 24 ,1996

.'.

493