JPH01139611A - Production of expanded synthetic resin - Google Patents

Abstract

PURPOSE:To obtain the title excellent resin without a fear of destroying the ozonosphere, by reacting an active hydrogen compound with a polyisocyanate compound using trichlorodifluoroethane as a foaming agent. CONSTITUTION:(A) An active hydrogen compound (e.g., phenolic resin precondensate) having >=2 active hydrogen-containing functional groups reactive with isocyanate groups is reacted with (B) a polyisocyanate compound (e.g., tolylene diisocyanate) in the presence of (C) a low-boiling halogenated hydrocarbon based foaming agent to produce an expanded synthetic resin. In the process, preferably 20-60wt.% [based on the component (A)] 1,1,2-trichloro-2,2- difluoroethane is used as the component (C).

Description

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

[Prior art fiFr] It is widely practiced to produce a foamed synthetic resin by reacting an active hydrogen compound having two or more active hydrogen-containing groups that react with an isocyanate group with a polyisocyanate compound in the presence of a catalyst and a blowing agent. It is. 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 (n-11) is mainly used. Also, it is usually
Water is further used in combination with -1'I. moreover,
When foaming is carried out by the froth method or the like, dichlorodifluoromethane (n-12), which has a lower boiling point and is a gas at normal temperature and normal pressure, is used together with these. Various proposals have been made that other relatively low-boiling chlorinated fluorinated hydrocarbons could be used as blowing agents.
With the exception of G1 and R-12, none of them have been widely used. Moreover, the use of other low boiling point halogenated hydrocarbon foaming agents such as methylene chloride in place of the chlorinated fluorinated hydrocarbon foaming agent 71J has also been proposed.

[Problems to be solved by the invention] Chlorinated fluorinated hydrocarbons that are extremely stable in the atmosphere, such as N-11 and N-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. 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 To-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 the method for producing a foamed synthetic resin by reacting an active hydrogen compound and a polyisocyanate compound in the presence of a low boiling point halogenated hydrocarbon blowing agent,
411 points 1,1.2 as a halogenated hydrocarbon blowing agent
- A method for producing a foamed synthetic resin, characterized by using trichloro-2,2-difluoroethane.

1,1,2-1-lichloro-2,2-difluoroethane, which is the blowing agent in the present invention, is a compound with a boiling point of 71.9°C, and since it is a chlorinated fluorinated hydrocarbon containing a hydrogen atom, it There is considered to be little risk of destruction.

Since its boiling point is roughly close to It-11, it can be used as a blowing agent in place of It-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 include the current blowing agents rt-xi and R
-12, other low-boiling halogenated hydrocarbons, low-boiling hydrocarbons, and inert gases. Although R-11 and R-12 may cause ozone layer depletion by themselves, their usage can be reduced without reducing their usage when used in combination with 1,1,2-1-dichloro-2,2-difluoroethane. can.

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 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 a main component and also 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 condensates) can also be used. Polyols include polyneedle polyol, polyester polyol,
Examples include polyhydric alcohols and diethylene polymers containing hydroxyl groups. In particular, it consists of one or more types of polyether polyols, but it is preferable to use it 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 needle, 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 isocyanate 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, isophorone diisocyanate, hexamethylene diisocyanate, prepolymer type modified products thereof, and nurate modified products. body, urea denatured body, 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 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 foam obtained by using a polyol or polyol mixture E aromatic polyisocyanate compound having a hydroxyl value of 200 to 1000. 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 %, especially 20 to 60 weight % is suitable. 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 liters of water.
In the case of microcellular elastomers, 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 2] 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: Propylene oxide with toluene diamine The foaming evaluation of a polyether polyol having a hydroxyl value of 440 was carried out as follows. Silicone foam stabilizer (Shin-Etsu Chemical brand name) per 100 parts of polyol
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, and an appropriate amount of 1,1,2-trichloro-2,2-difluoroethane. and polymethylene polyphenylisocyanate (MD Kasei ■ trade name PAP1135) were mixed at a liquid temperature of 20°C, and a size of 200 mm x 200 mm was prepared.
The mixture was placed in a wooden box measuring 200 mm x 200 mm and foamed for evaluation. In addition, as a comparative example, I+-11 was foamed in the same manner and evaluated. The amount of foaming agent used was adjusted so that the core density of the foam was 30±2 kg/m'.

The results are shown in Table 1.

The criteria for judgment are as follows.

Q: Equivalent or better than 11-11 Δ: Slightly inferior to 1-11 X: Inferior to 11-11 Table 1 Polyol a b c Type Compatibility with polyol OO△ Form appearance OΔ O Core density 31.0 0.4 29
．． 9 Compressive strength ○ △ △ Thermal conductivity
△ ○ O [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 n-1t, which may cause ozone layer depletion. It is.

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 1,1,2-trichloro-2,2-difluoroethane as a low-boiling halogenated hydrocarbon foaming agent.