JPH01149819A - Production of foamed synthetic resin - Google Patents

Abstract

PURPOSE:To obtain the title resin having excellent property, without causing the destruction of ozonosphere, by reacting an active hydrogen compound with a polyisocyanate compound in the presence of monobromomonochloromethane as a foaming agent. CONSTITUTION:A foamed synthetic resin is produced by reacting (A) an active hydrogen compound having >=2 functional groups containing active hydrogen reactive with isocyanate group (e.g., polyether polyol) with (B) a polyisocyanate compound (e.g., tolylene diisocyanate) in the presence of (C) a low-boiling halogenerated hydrocarbon foaming agent. In the above process, monobromomonochloromethane is used as the foaming agent in an amount of preferably 20-60wt.% (based on the component A).

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] Two or more active hydrogen-containing groups that can react with isocyanate groups.
It is widely practiced to produce a foamed synthetic resin by reacting an active hydrogen compound with a polyisocyanate compound in the presence of a catalyst and a blowing agent. Examples of active hydrogen compounds include polyhydroxy compounds and polyamine compounds. The resulting foamed synthetic resins include, for example, polyurethane foam, polyisocyanurate foam,
Examples include polyurea foam. In addition, examples of foamed synthetic resins with relatively low foaming include microcellular polyurethane elastomer and microcellular polyurethane urea elastomer.

Various compounds are known as blowing agents for producing the above-mentioned foamed synthetic resin, and trichlorofluoromethane (R-11) 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., in addition to these, difluoromethane (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. It is now believed that the decomposed substances are decomposed by the action of ultraviolet rays, etc., and that the decomposed products destroy the ozone layer. Chlorinated fluorinated hydrocarbons such as those mentioned above used as blowing agents,
Because some of it leaks into the atmosphere, there are concerns that its use could be part of the cause of ozone layer depletion. 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 incyanate groups
In the 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 point halogenated hydrocarbon blowing agent, monobromomonochloromethane is used as the low boiling point halogenated hydrocarbon blowing agent. A method for producing a foamed synthetic resin, characterized by using. Monobromomonochloromethane, which is a blowing agent in the present invention, is a compound with a boiling point of 67°C, and since it is a halogenated hydrocarbon containing a hydrogen atom, it is thought that there is little risk of the ozone layer being destroyed. Furthermore, since its boiling point is close to that of R-11, it can be used as a blowing agent in place of R-11. 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. Examples of blowing agents other than water that can be used in combination include current blowing agents R-11 and R-12, other low-boiling halogenated hydrocarbons, low-boiling hydrocarbons, and inert gases. R-11
Although R-12 itself may cause ozone layer depletion, its usage can be reduced by using it in combination with monobromomonochloromethane. 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 amino 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, widely used polyols are preferred, but compounds having two or more phenolic hydroxyl groups (for example, phenol resin initial clamping products) can also be used. Polyols include polyether polyols, polyester polyols,
Examples include 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 called a polymer polyol or a graft polyol, in which fine particles of a vinyl polymer are dispersed in a mainly polyether 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,
These include diethylene glycol, dipropylene glycol, glycerin, trimethylolpropane, pentaerythritol, jetanolamine, and triethanolamine. The hydroxyl value of the polyol or its mixture is approximately 2
It is often selected from 0 to 1000 depending on the purpose.

Examples of polyisocyanate compounds include aromatic, alicyclic, or aliphatic polyisocyanates having two or more incyanate groups, mixtures of two or more thereof, and modified polyisocyanates obtained by modifying them. Specifically, for example, polyisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, polymethylene polyphenylisocyanate (commonly known as crude MDI), xylylene diisocyanate, inphorone diisocyanate, hexamethylene diisocyanate, prepolymer type modified products thereof, and nurate. There are modified forms, urea modified forms, etc.

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, which promote the reaction between active hydrogen-containing groups and incyanate 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 having a hydroxyl value of about 200 to 1,000 and aromatic polyisocyanate compounds. When producing these hard foams, the amount of halogenated hydrocarbon blowing agent used in the present invention is 5 to 150% based on the active hydrogen compound.
Weight percentages are suitable, especially 20 to 60 weight percent. In addition, 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 0 to 1 of water.
In the case of a microcellular elastomer, it is preferable to use water in an amount of 0 to 5% by weight.

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: A polyether polyol with a hydroxyl value of 420 made by reacting glycerin with propylene oxide Polyol B: A polyether polyol with a hydroxyl value of 450 made by reacting sucrose with propylene oxide and ethylene oxide Polyol C: A polyether polyol with a hydroxyl value of 450 made by reacting propylene oxide with sucrose Polyol C: Propylene oxide added with toluene diamine The foaming evaluation of the reacted 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 mixture 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 monobromomonochloromethane, and polymethylene polyphenylisocyanate (MD Kasei) ■ Mix the product (trade name: PAP1135) at a liquid temperature of 20℃,
It was placed in a wooden box measuring 200 mm x 200 mm x 200 mm, and was foamed for evaluation. Also, as a comparative example, R
-11 was similarly foamed and evaluated. The amount of foaming agent used was adjusted so that the core density of the foam was 30±2 kg/m3.

The results are shown in Table 1.

The criteria for judgment are as follows.

○: Equivalent to or better than R-11 △: Slightly inferior to R-11 x: Inferior to R-11 Table 1 Polyol a b Type of C Compatibility with polyol ○ O○ Form appearance △ 0 0 Core density
29.8 30.2 30.4 Compressive strength
○ △ △ Thermal conductivity 0 0
0 [Effects of the Invention] The present invention makes it possible to produce a good foamed synthetic resin without substantially using chlorinated fluorinated hydrocarbons such as R-11, which may cause ozone layer depletion. .

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. A method for producing a foamed synthetic resin, the method comprising using monobromomonochloromethane as a low-boiling halogenated hydrocarbon foaming agent.