JPH04359934A - Treatment of blowing agent for synthetic resin foam - Google Patents

Abstract

PURPOSE:To efficiently remove impurities formed by a chemical change of a blowing agent when a synthetic resin foam such as a urethane foam is used as a heat insulating material or the like. CONSTITUTION:Impurities such as 1-chloro-2,2,2-trifluoroethane and 1-chloro-1- fluoroethane formed when a hydrochlorofluorocarbon blowing agent such as 1,1-dichloro-2,2,2-trifluoroethane or 1,1-dichloro-1-fluoroethane undergoes a chemical change are removed by adsorption on an adsorbent such as active carbon or zeolite.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating impurities produced by chemical changes in hydrogen-containing chlorinated fluorinated hydrocarbon blowing agents for synthetic resin foams.

0002

BACKGROUND OF THE INVENTION Conventionally, trichlorofluoromethane (hereinafter referred to as Freon 11) has been used in polyurethane foaming. However, fully halogenated hydrocarbons
Environmental problems regarding the ozone layer have been pointed out, and there is an urgent need to develop alternative materials. As substitutes for Freon 11, 1,1-dichloro-2,2,2-trifluoroethane (hereinafter referred to as Freon 123) and 1,1-dichloro-
1-Fluoroethane (hereinafter referred to as Freon 141b)
is considered to be the most likely. Freon 123 and Freon 141b
It has been pointed out that when used as a urethane blowing agent, highly toxic impurities are produced due to chemical changes in the blowing agent during foaming and storage.

The main impurities are 1-chloro-2,2,2-trifluoroethane (hereinafter referred to as Freon 133a) from Freon 123, and 1-chloro-1-fluoroethane (hereinafter referred to as Freon 133a) from Freon 141b. Freon 15
1a) is generated. The causes of these impurities include polyol, which is a raw material for polyurethane foam,
Examples include reactions between isocyanates, catalysts, foam stabilizers, etc. and foaming agents when they are mixed and stored, and thermal decomposition due to exothermic reactions during the foaming process.

0004

[Problems to be Solved by the Invention] Synthetic resin foams such as polyurethane foams are mainly used as insulation materials for household refrigerators, showcases, buildings, etc. for the purpose of storing food. Highly toxic impurities generated during foaming and storage are
If they accumulate in food or diffuse into the living environment, they are likely to have an adverse effect on the human body, and from the standpoint of safety, it is extremely important to remove impurities.

[0005]

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention is the result of repeated studies on a method for removing impurities from hydrogen-containing chlorinated fluorinated hydrocarbon blowing agents such as Freon 123 and Freon 141b. The present inventors have discovered that impurities can be adsorbed and removed by using an adsorbent, and have completed the present invention. That is, the present invention
This is a method for treating a blowing agent for synthetic resin foam, which is characterized in that impurities generated by chemical change of a hydrogen-containing chlorinated fluorinated hydrocarbon blowing agent for synthetic resin foam are adsorbed onto an adsorbent.

[0006] Examples of the adsorbent in the present invention include activated carbon and zeolite. Various activated carbons such as coconut shell, charcoal, coal, petroleum pitch, etc. can be used as the activated carbon, and the pore diameter is 3 x 10-8 cm to 10 x 10-8 cm.
Preferably, m. The activated carbon may be in the form of powder, granules, or fibers.

Zeolite is a type of mineral belonging to the silicate group represented by the following general formula, and is known to be a natural product or a synthetic product. Mx/n[(AlO2)x・(SiO2)y]・wH2
O Here, n is the number of cations M (alkali metals, alkaline earth metals such as Na, K, Ca, etc.), w is water per unit cell, x and y are the total number of tetrahedra per unit cell. . In addition, synthetic zeolites include A-type zeolite and X-type zeolite.
Type zeolites, Y type zeolites, etc. are known, and natural or synthetic zeolites can be used as the zeolite of the present invention. Zeolite pores are 3 x 10-8
cm to 10×10 −8 cm is particularly preferred. These activated carbon and zeolite can also be used together.

[0008] As the synthetic resin foam in the present invention,
Examples include polyurethane foam, phenol resin foam, polystyrene resin foam, and the like.

The adsorbent in the present invention can be effectively used by directly mixing it into the foam or into the foam raw material composition, or by installing it indirectly. Specifically, foaming agents such as Freon 123 and Freon 141b,
A powder or granular adsorbent is present in a polyurethane raw material composition containing polyols, isocyanates, catalysts, foam stabilizers, etc. to prevent impurities generated during storage or urethane foaming or impurities present in the manufactured foam. can be removed by adsorption. On the other hand, indirectly, by providing an adsorbent phase on the surface of the synthetic resin foam, impurities coming out of the foam can be effectively adsorbed and removed. Alternatively, it is also effective to install an adsorbent inside a household refrigerator or showcase, or inside a building.

[0010] The amount added is not particularly limited, but if it is directly mixed into a foam, it should be within 5 wt%, preferably within 1 wt%, based on the foaming agent, considering the deterioration of foam performance. It is. The impurities that can be adsorbed and removed by the present invention include Freon 133a, 151a, unsaturated hydrocarbons, etc., which are generated by chemical changes of hydrogen-containing chlorinated fluorinated hydrocarbon blowing agents such as Freon 123, 141b, etc. It is not limited.

[0011]

[Examples] The present invention will be specifically explained below with reference to Examples, but the present invention is not limited to these Examples.

Examples 1 to 6 Table 1 shows the results when the adsorbent was directly incorporated into the polyurethane foaming agent. The following mixture was prepared as a sample. Ethylenediamine polyol 100 parts by weight Catalyst Dabco 33LV
1 part by weight (manufactured by Sankyo Air Products) Foam stabilizer SH-193
1 part by weight (manufactured by Toray Silicone) Pure water
4 parts by weight Freon 123
40 parts by weight Isocyanate MR-200 2
65.5 parts by weight (manufactured by Nippon Polyurethane Co., Ltd.)

[0013] An adsorbent is mixed with the mixed liquid, and a 20×20
After forming a foam in a 20 cm x 20 cm wooden box, the impurity removal effect was measured by analyzing the amount of CFC 133a impurity present in the foam using gas chromatography. The results are shown in Table 1. Adsorbent loading is the concentration in the blowing agent.

[0014]

[Table 1]

Examples 7 to 12 On the other hand, as an example of indirect inclusion, air containing 10 g of adsorbent and 0.01 vol% of Freon 133a as an example of an impurity was sealed in a 1 m3 sealed container made of synthetic resin. Thereafter, the impurity removal effect was measured by forcibly circulating the inside of the container using a fan and analyzing the concentration of Freon 133a remaining in the container using gas chromatography. The results are shown in Table 2.

[0016]

[Table 2]

[0017] The adsorbents in Tables 1 and 2 represent the following. MS-13X: X-type zeolite (manufactured by Union Showa) M
S-5A: A-type zeolite (manufactured by Union Showa) MS
-4A: A type zeolite (manufactured by Union Showa Co., Ltd.) MS-
3A: A type zeolite (manufactured by Union Showa) 4GG
:Activated carbon manufactured by Kuraray Co., Ltd.

[0018]

[Effect of the invention] By the method of the present invention, synthetic resin foam,
For example, when a urethane foam is used as a heat insulating material, it is possible to efficiently remove impurities caused by chemical changes in the foaming agent.

Claims (9)

[Claims] 1. Treatment of a blowing agent for synthetic resin foam, characterized in that impurities generated by chemical change of a hydrogen-containing chlorinated fluorinated hydrocarbon blowing agent for synthetic resin foam are adsorbed onto an adsorbent. Method. 2. The treatment method according to claim 1, wherein the impurities are generated during the production of the synthetic resin foam. 3. The treatment method according to claim 1, wherein the impurity is present in the produced synthetic resin foam. 4. The treatment method according to claim 1, wherein the impurities come out of the produced synthetic resin foam. 5. The treatment method according to claim 1, wherein the impurities are generated in the synthetic resin foam raw material composition. 6. The treatment method according to claim 1, wherein the adsorbent is zeolite. 7. The treatment method according to claim 1, wherein the adsorbent is activated carbon. 8. The hydrogen-containing chlorinated fluorinated hydrocarbon blowing agent is 1,1-dichloro-2,2,2-trifluoroethane, and the impurity is 1-chloro-2,2,2-trifluoroethane. The processing method according to claim 1. Claim 9: Claim 1 wherein the hydrogen-containing chlorinated fluorinated hydrocarbon blowing agent is 1,1-dichloro-1-fluoroethane, and the impurity is 1-chloro-1-fluoroethane.
processing method.