JPH01135817A - Production of expanded synthetic resin - Google Patents

Abstract

PURPOSE:To obtain the present resin without fear of the stratospheric ozone layer depletion, by reaction between an active hydrogen compound and polyisocyanate compound using, as the foaming agent, a tetrafluorocyclobutane. CONSTITUTION:The objective resin can be obtained by reaction between (A) an active hydrogen compound having two or more active hydrogen-contg. functional groups reactive with isocyanate group and (B) a polyisocyanate compound in the presence of a low-boiling halogenated hydrocarbon-based foaming agent, i.e., pref. 20-60wt.%, based on the component A, of 1,1,2,2-tetrafluorocyclobutane pref. in combination with 1-5wt.% water.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a method for producing a foamed synthetic resin such as a polyurethane foam, and in particular a method for producing a foamed synthetic resin characterized by the use of a specific blowing agent. It is about the method.

[Prior Art] It is widely practiced to produce a foamed synthetic resin by reacting an active hydrogen compound having two or more active hydrogen-containing groups capable of reacting with an isocyanate group with a polyisocyanate compound in the presence of a catalyst and a blowing agent. ing. Examples of active hydrogen compounds include polyhydroxy compounds and polyamine compounds. Examples of the resulting foamed synthetic resin include polyurethane foam, polyisocyanurate foam, and polyurea foam. Examples of foamed synthetic resins with relatively low foaming include microcellular polyurethane elastomer and microcellular polyurethane urea elastomer.

Although various compounds are known as blowing agents for producing the above-mentioned foamed synthetic resin, trichlorofluoromethane (R-I+) is mainly used. Also, usually R-
Water is further used in combination with 11. Furthermore, when foaming is carried out by the froth method etc., dichlorodifluoromethane (R
-12) is used in combination. Various proposals have been made that other relatively low-boiling chlorinated fluorinated hydrocarbons can be used as blowing agents;
With the exception of No. 11 and R-12, they have not yet come into widespread use. It has also been proposed to use other low boiling point halogenated hydrocarbon blowing agents, such as methylene chloride, in place of the chlorinated fluorinated hydrocarbon blowing agents.

[Problems to be solved by the invention] Chlorinated fluorinated hydrocarbons that are extremely stable in the atmosphere, such as R-11 and R-12, which have been widely used in the past, reach the ozone layer above the atmospheric layer without being decomposed. There, it was thought that it would be decomposed by the action of ultraviolet rays, etc., and that the decomposed products could destroy the ozone layer. Some of the chlorinated fluorinated hydrocarbons used as blowing agents, such as those listed in item 1 above, leak into the atmosphere, and there are concerns that their use may be part of the cause of ozone layer depletion. ing. Therefore, in place of R-11 and R-12, it is desired to develop a blowing agent that is less likely to cause ozone layer depletion.

[Means for Solving the Problems] The present invention provides the following inventions to solve the above-mentioned problems.

2 active hydrogen-containing functional groups that can react with isocyanate groups
In a method for producing a foamed synthetic resin by reacting an active hydrogen compound having the above and a polyisocyanate compound in the presence of a low-boiling halogenated hydrocarbon blowing agent, 1. 1. A method for producing a foamed synthetic resin, the method comprising using 1,2,2-tetrafluorocyclobutane. 1 which is a blowing agent in the present invention
, 1,2,2.2-tetrafluorocyclobutane at 50℃
Since it is a fluorinated hydrocarbon that contains hydrogen atoms and does not contain chlorine, it is thought that there is little risk of the ozone layer being destroyed. Furthermore, its boiling point is R-
Since it is close to 11, it can be used as an alternative blowing agent.

The halogenated hydrocarbon blowing agents in the present invention can be used alone or in combination with other blowing agents. In particular, water is often used in combination with the halogenated hydrocarbon blowing agent. Other foaming agents that can be used in combination with other types of foaming agents, such as the current foaming agent R-11 and R-
12. Other low-boiling halogenated hydrocarbons, low-boiling hydrocarbons, inert gases, etc. Although R-11 and R-12 may cause ozone layer destruction by themselves, their usage can be reduced by using them in combination with 1.1.2.2-tetrafluorocyclobutane. Other low-boiling halogenated hydrocarbons include halogenated hydrocarbons that do not contain fluorine atoms, such as methylene chloride, and fluorine-containing halogenated hydrocarbons other than those mentioned above. Low-boiling hydrocarbons include butane and hexane, and inert gases include air and nitrogen.

2 active hydrogen-containing functional groups that can react with isocyanate groups
The active hydrogen compound having the above is a compound having two or more active hydrogen-containing functional groups such as a hydroxyl group or an amine group, or a mixture of two or more such compounds. Particularly preferred are compounds having two or more hydroxyl groups, mixtures thereof, or mixtures containing the same as the main component and further containing polyamine or the like. As the compound having two or more hydroxyl groups, polyols commonly used are preferred, but compounds having two or more phenolic hydroxyl groups (for example, phenol resin initial condensates) can also be used.As the polyols,
Examples include polyether polyols, polyester polyols, polyhydric alcohols, and diethylene polymers containing hydroxyl groups. In particular, it is preferable to use only one or more types of polyether polyols, or to use them as a main component in combination with polyester polyols, polyhydric alcohols, polyamines, alkanolamines, and other active hydrogen compounds. The polyether polyol is preferably a polyether polyol obtained by adding a cyclic ether, particularly an alkylene oxide such as propylene oxide or ethylene oxide, to a polyhydric alcohol, saccharide, alkanolamine, or other initiator. Further, as the polyol, it is also possible to use a polyol composition in which fine particles of vinyl polymer are dispersed in a mainly polyether polyol called a polymer polyol or kraft polyol. Polyester polyols include polyhydric alcohol-polycarboxylic acid condensation polyols and cyclic ester ring-opening polymer polyols, and polyhydric alcohols include ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, glycerin, and trivalent alcohols. Examples include methylolpropane, pentaerythritol, jetanolamine, and triethanolamine. The hydroxyl value of the polyol or its mixture is often selected from about 20 to +000 depending on the purpose.

Polyisocyanate compounds include aromatic, alicyclic, or aliphatic polyisocyanates having two or more isocyanate groups, mixtures of two or more thereof, and modified polyisocyanates obtained by modifying them. . Specifically, for example, tolylene diisocyanate, diphenylmethane diisocyanate, polymethylene polyphenylisocyanate (common name: crude MDI)
Examples include polyisocyanates such as xylylene diisocyanate, isophorone diisocyanate, and hexamethylene diisocyanate, as well as prepolymer-type modified products, nurate-modified products, and urea-modified products thereof.

When reacting active hydrogen compounds and polyisocyanate compounds, the use of catalysts is usually required. As a catalyst,
Metal compound catalysts such as organotin compounds and tertiary amine catalysts such as triethylenediamine are used to promote the reaction between active hydrogen-containing groups and isocyanate groups. Further, a polymerization catalyst that causes isocyanate groups to react with each other, such as a carboxylic acid metal salt, is used depending on the purpose. Furthermore, foam stabilizers are often used to form good foam. Examples of the foam stabilizer include silicone foam stabilizers and fluorine-containing compound foam stabilizers. Other optional additives include fillers, stabilizers, colorants, flame retardants, and the like.

Using these raw materials, polyurethane foam, urethane-modified polyisocyanate foam, microcellular polyurethane elastomer, microcellular polyurethane urea elastomer, microcellular polyurea elastomer, and other foamed synthetic resins can be obtained.

Polyurethane foam can be broadly divided into rigid polyurethane foam, semi-rigid polyurethane foam, and flexible polyurethane foam. The present invention is particularly useful in the production of rigid polyurethane foams, urethane-modified polyisocyanurate foams, and other rigid foams, which are fields in which halogenated hydrocarbon blowing agents are used in large quantities. Among these, it is particularly useful in the production of rigid polyurethane foams obtained by using polyols or polyol mixtures with a hydroxyl group restriction of 200 to 1,000 and aromatic polyisocyanate compounds. When producing these hard foams, the amount of the halogenated hydrocarbon blowing agent used in the present invention is 5 to 15% based on the active hydrogen compound.
0% by weight, especially 20-60% by weight is suitable. Also,
At the same time, it is preferable to use water in an amount of 0 to 10% by weight, particularly 1 to 5% by weight, based on the active hydrogen compound. On the other hand, in the case of flexible polyurethane foam, semi-rigid polyurethane foam, and microcellular elastomer, the halogenated hydrocarbon blowing agent in the present invention is preferably used in an amount of 5 to 150% by weight based on the active hydrogen compound. For soft urethane foam and semi-hard urethane foam, add water to 0~
In the case of a microcellular elastomer, it is preferable to use water in an amount of 0 to 5% by width.

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited to these Examples.

[Example] Foaming evaluation of the halogenated hydrocarbon blowing agent in the present invention was conducted for the following polyols.

Polyolumi: Polyether polyol with a hydroxyl value of 420 made by reacting glycerin with propylene oxide Polyol B: Polyether polyol with a hydroxyl value of 450 made by reacting sucrose with propylene oxide and ethylene oxide Polyol C: Propylene oxide with toluene diamine The foaming evaluation of polyether polyol having a hydroxyl value of 440 was carried out as follows. For 100 parts by weight of polyol, silicone foam stabilizer (Shin-Etsu Chemical ■ trade name)
A mixed solution of 2 parts of F-338), 1 part of water, the necessary amount of N,N-dimethylcyclohexylamine as a catalyst to give a gel time of 45 seconds, an appropriate amount of I, I, 2,2-tetrafluorocyclobutane, and polyester. Add methylene polyphenylisocyanate (MD Kasei ■ trade name PAP1135) to liquid fu.
Mix at 120℃, 200mmX200mmX200m
The mixture was placed in a wooden box of 1.5 mm and foamed for evaluation. Further, as a comparative example, R-11 was similarly foamed and evaluated. When using a foaming agent, the core density of the foam should be 30±2 kg/
It was adjusted to be m3.

The results are shown in Table 1.

The rules for judgment are as follows.

○: Equivalent or better than R-11 Δ: Slightly inferior to R-11 x: Inferior to R-11

Claims (1)

[Claims] 1. Foaming synthesis by reacting an active hydrogen compound having two or more active hydrogen-containing functional groups capable of reacting with an isocyanate group with a polyisocyanate compound in the presence of a low-boiling halogenated hydrocarbon blowing agent. 1. A method for producing a foamed synthetic resin, the method comprising using 1,1,2,2-tetrafluorocyclobutane as a low-boiling halogenated hydrocarbon foaming agent.