JPH03119039A - Production of expanded synthetic resin - Google Patents

Abstract

PURPOSE:To reduce a fear of destroying ozonosphere and produce an excellent expanded synthetic resin by reacting an active hydrogen-containing compound with a polyisocyanate in the presence of a specific low-boiling halogenated hydrocarbon-based foaming agent. CONSTITUTION:(A) A compound (e.g. polyether-based polyol or polyhydric alcohol) having >=2 active hydrogen-containing groups reactive with isocyanates is reacted with (B) a polyisocyanate compound in the presence of a catalyst, a foam stabilizer, etc., using (C) a low-boiling halogenated hydrocarbon-based foaming agent composed of 50-98wt.% 1,1-dichloro-2,2,2-trifluoroethane and 2-50wt.% trichlorofluoromethane to produce an expanded synthetic resin. The use of the component (C) in an amount of 5-150wt.%, especially 20-60wt.% based on the component (A) is more effective especially in producing rigid polyurethane foams.

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. Examples of active hydrogen compounds include polyhydroxy compounds and polyamine compounds. Examples of foamed synthetic resins that can be obtained include polyurethane foam, polyisocyanurate foam, and polyurea foam. Examples of the foamed synthetic resin 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-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., 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] R-11, which has been used in the past, generally has low solubility in active hydrogen compounds such as polyols, and mixed component systems containing both tend to have phase separation problems. Therefore, there was a problem of narrowing the range of active hydrogen compounds that can be used.If phase separation occurs in the mixed system with active hydrogen compounds, R-11 with high specific gravity will accumulate in the storage container, resulting in a heterogeneous mixed liquid. As a result, the reaction equivalent with the polyisocyanate compound is disturbed, making it impossible to obtain a normal foam.Even if there is no clear separation into two phases, poor solubility can be caused by mixing with the polyisocyanate compound during foam production. This can easily lead to defects, unreacted components remaining, and the generation of rough bubbles called voids.Furthermore, R-11 and R-12 are extremely stable in the atmosphere, so they reach the ozone layer above the atmosphere without being decomposed, where they are exposed to ultraviolet rays. It is now believed that the decomposition products may destroy the ozone layer.

Some of the chlorinated fluorinated hydrocarbons used as blowing agents leak into the atmosphere, and there are concerns that their 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 (and has no problem in solubility with active hydrogen compounds such as polyols).

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

In a method for producing a foamed synthetic resin by reacting an active hydrogen compound having two or more active hydrogen-containing groups capable of reacting with isocyanate with a polyisocyanate compound in the presence of a low-boiling halogenated hydrocarbon blowing agent, 1,1-dichloro-2,2,
2-) A method for producing a foamed synthetic resin, characterized in that a mixture of refluoroethane and trichlorofluoromethane is used, the former containing 50 to 98% by weight and the latter containing 2 to 50% by weight.

R-123 (1,
1-dichloro-2,2,2-trifluoroethane) is a compound with a boiling point of 27.6°C, and since its boiling point is close to that of R-11, it can be used as a blowing agent in place of R-11. This R-123 has high solubility in active hydrogen compounds such as polyols, solubility in active hydrogen compounds in the presence of water, and solubility in fluorine-containing halogenated hydrocarbon blowing agents such as R-11 and R-12. By mixing a portion of R-11 with the conventional blowing agent R-11, it is possible to reduce the problems caused by the solubility between the halogenated hydrocarbon blowing agent and the active hydrogen compound. I can do it.

Furthermore, since R-123 is a fluorinated chlorinated hydrocarbon having a hydrogen atom, it is thought that the risk of ozone destruction described above is low. Although R-11 itself has the risk of depleting the ozone layer, its usage can be reduced by using it in combination with R-123.

By mixing conventional R-11 and R-123, it is possible to obtain a blowing agent that has little risk of ozone layer depletion (and has no problem in solubility with active hydrogen compounds.The composition of the mixed blowing agent at this time As for R-11 2 to 50% by weight,
Preferably, R-123 is 50 to 98% by weight.

The halogenated hydrocarbon blowing agents in the present invention can be used alone or in combination with other blowing agents. In particular, water is used in combination with the above-mentioned halogenated hydrocarbon blowing agent.Other blowing agents other than waterside that can be used in combination include low boiling point halogenated hydrocarbons such as R-12, low boiling point hydrocarbons, etc. , inert gas, etc.Other low-boiling halogenated hydrocarbons include halogenated hydrocarbons that do not contain fluorine atoms such as methylene chloride, and R-134a%.
There are fluorine-containing halogenated hydrocarbons such as R-141b, R-142b, and R-22. Low-boiling hydrocarbons include butane, pentane, 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 condensate) 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. Compounds having two or more phenolic hydroxyl groups include resol-type initial condensates in which phenols are condensed and bonded with excess formaldehyde in the presence of an alkali catalyst; There are benzylic-type initial condensates made by reacting excess phenols with formaldehyde in the presence of an acid catalyst, and novolac-type initial condensates. The molecular weight of these initial condensates is preferably 200 to 10,000. Here, phenols mean those in which one or more carbon atoms of the skeleton forming a benzene ring are directly bonded to a hydroxyl group, and also include those having other substituent bonding groups within the same structure. Typical examples include phenol, cresol, and bisphenol A rsorcinol. Further, formaldehydes are not particularly limited, but formalin and paraformaldehyde are preferred. The hydroxyl value of the polyol or the mixture of active hydrogen compound hydrogen is often selected from about 20 to 1000 depending on the purpose.

Examples of polyisocyanate compounds include aromatic and alicyclic compounds having two or more incyanate groups.

Alternatively, there are aliphatic polyisocyanates, mixtures of two or more thereof, and modified polyisocyanates obtained by modifying them. Specifically, for example, tolylene diisocyanate, diphenylmethane diisocyanate, polymethylene polyphenylisocyanate (commonly known as:
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 foam obtained by using a polyol or polyol mixture having a hydroxyl value of 200 to 1000 and an aromatic polyisocyanate compound. 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.

Polyoluminum: A polyester polyol with a hydroxyl value of 315 obtained by reacting phthalic anhydride with diethylene glycol Polyol b: A polyether polyol with a hydroxyl value of 440 obtained by reacting toluene diamine with ethylene oxide The foaming evaluation was performed as follows. For 100 parts by weight of polyol, silicone foam stabilizer (Shin-Etsu Chemical brand name)
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, the foaming agent in the present invention (■ to ■), an appropriate amount of the mixed liquid, and polymethylene polyphenyl. Isocyanate (MD Kasei (trade name: PAP1135) was mixed at a liquid temperature of 20°C, placed in a 200 mm x 200 mm x 200 mm wooden box, and foamed for evaluation. In addition, as a comparative example, R-11 was foamed in the same way. The amount of foaming agent used was adjusted so that the core density of the foam was 30±2 kg/m''.

■ R-1150% by weight R-12350% by weight ■ R
-1130% by weight R-12370% by weight■ R-11
10% by weight R-12390% by weight The results are shown in Table 1.

The criteria for judgment are as follows.

[Effects of the Invention] The present invention can 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. A method for producing a foamed synthetic resin by reacting an active hydrogen compound having two or more active hydrogen-containing groups capable of reacting with isocyanate with a polyisocyanate compound in the presence of a low-boiling halogenated hydrocarbon blowing agent. As a boiling point halogenated hydrocarbon blowing agent, 1,1-dichloro-2,
A method for producing a foamed synthetic resin, characterized in that a mixture of 2,2-trifluoroethane and trichlorofluoromethane is used, the former containing 50 to 98% by weight and the latter containing 2 to 50% by weight.