JPH02263842A - Production of expanded synthetic resin - Google Patents

Abstract

PURPOSE:To obtain the subject excellent resin without a fear of destroying ozonosphere by reacting an active hydrogen compound with a polyisocyanate compound in the presence of a specific low-boiling halogenated hydrocarbon- based foaming agent. CONSTITUTION:An active hydrogen compound (e.g. polyether-based polyol) having >=2 active hydrogen-containing functional groups reactive with isocyanate groups is reacted with a polyisocyanate compound (e.g. tolylene diisocyanate) in the presence of a low-boiling halogenated hydrocarbon-based foaming agent. In the process, a mixed foaming agent composed of CCl2HCF3 and CCl2FCH3 or a mixed foaming agent composed of CCl2HCF3, CCl2FCH3 and CCI3F is used as the above-mentioned foaming agent.

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. In addition, 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-11) is mainly used. Also, usually R
-11 and water is further supplied to the J valve. Furthermore, when foaming is carried out by the froth method or the like, dichlorodifluoromethane (R-12) having a lower boiling point (gaseous at normal temperature and normal pressure) is used together with these. Furthermore, various proposals have been made that other relatively low-boiling chlorinated fluorinated hydrocarbons can be used as blowing agents, but with the exception of R-11 and R-12 mentioned above, they are still not widely used. The use of other low boiling point halogenated hydrocarbon blowing agents such as methylene chloride in place of the chlorinated fluorinated hydrocarbon blowing agents has also been proposed.

[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 atmosphere without being decomposed. Therefore, it was thought that the above-mentioned chlorinated fluorinated hydrocarbons, which were used as blowing agents, were decomposed by the action of ultraviolet rays, etc., and the decomposed products were thought to destroy the ozone layer.
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, foaming agents that are less likely to cause ozone layer depletion are being developed.

CCIJCFs (R-123), CC12FCHi (
It is proposed to use R-141b).

R-141b and R-123 have a boiling point of 32°C, respectively.
Since it is a compound with a temperature of 27.1° C. and contains a hydrogen atom, it is thought that there is little risk of ozone destruction. Furthermore, since its boiling point is close to that of CC1,F (R-11), it is attracting attention as a promising candidate as a blowing agent to replace CC1,F (R-11). However, among these, R-123 has high solubility in active hydrogen compounds such as polyols, and it may be difficult to produce foams in the same way as conventional R-11. For example, if a blowing agent has high solubility, it will not only dissolve into active hydrogen compounds such as polyols, but also dissolve into the foamed synthetic resin that is produced, causing softening and shrinkage of the foam.
This can lead to cell formation and even bubble breakage. Also R
-141b has a smaller solubility problem with active hydrogen compounds than R-123, but has the problem that this substance is a flammable substance. Therefore, it is impossible to simply replace R-11 with these R-123 or R-141b. There is a need to develop blowing agents that solve these problems.

[Means for Solving the Problems] The present invention provides the following inventions that have been made 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 point halogenated hydrocarbon blowing agent, the low boiling point halogenated hydrocarbon blowing agent includes CC1, HCFL and Mixed blowing agent consisting of CC1tFCH8 or CC1,HC
A method for producing a foamed synthetic resin, characterized in that a mixed blowing agent consisting of Fs, cctzpcus and CC1,F is used.

R-123 and R-141b which are blowing agents in the present invention
The mixture has an appropriate solubility for active hydrogen compounds such as polyols, and is out of the flammable range of R-141b because it contains R-123, which is nonflammable.

By adding a mixture of R-123 and R-141b to R-11, it is possible to arbitrarily reduce the amount of R-11 used, which may cause ozone destruction, while maintaining the performance of the foam.

The ratio of the mixed blowing agent in the present invention is R-123/R-
141b=2-98% by weight/2-98% by weight, preferably 2-80% by weight/20-98% by weight, R-1
23/R-141b/R-11=2-58% by weight/2
~58% by weight/40-70% by weight, preferably 1-39
Weight/1-39% by weight 155-95% by weight.

The mixed blowing agent in the present invention can of course 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 waterside include, for example, R
-12, other low-boiling halogenated hydrocarbons, low-boiling hydrocarbons, and inert gases. 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, polyols used in Hiroshima are preferred, but compounds having two or more phenolic hydroxyl groups (for example, phenol resin initial condensates) can also be used.As the polyols, polyether-based polyol, polyester polyol,
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 nil polymer are dispersed in a 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,
Examples 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 precondensates made by reacting excess phenols with formaldehyde in the presence of an acid catalyst, and novolac-type precondensates. 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 there are no other compounds in the same structure. Also included are those having a substituted bonding group.

Typical examples include phenol, cresol, bisphenol A, and resorcinol. Further, the formaldehyde is not particularly limited, but formalin and formaldehyde are preferable. 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, 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,
A metal compound catalyst such as a bounded tin compound or a tertiary amine catalyst such as triethylenediamine is used to promote the reaction between an active hydrogen-containing group and an isocyanate group. 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 foams can be roughly divided into rigid polyurethane foams, semi-rigid polyurethane foams, and flexible polyurethane foams.The present invention focuses on rigid polyurethane foams and urethane-modified polyisocyanurate foams, which are fields in which halogenated hydrocarbon blowing agents are used in particular. , and other rigid foams. 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, at the same time, water is 0 to 0 to the active hydrogen compound.
Preference is given to using 10% by weight, especially 1 to 5% by weight. 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. In the case of soft urethane foam and semi-rigid urethane foam, it is preferable to use 0 to 10% by weight of water, and in the case of microcellular elastomer, it is preferable to use 0 to 5% by weight of water.

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 oxidePolyol b: A polyether polyol with a hydroxyl value of 450 made by reacting propylene oxide and ethylene oxide with shake rosePolyol C: Propylene oxide added with toluenediamine The foaming evaluation of the reacted polyether polyol having a hydroxyl value of 440 was carried out as follows. Silicone foam stabilizer (Shin-Etsu Chemical ■Product name F-) is added to 100 parts by weight of polyol.
338), 1 part of water, N%N-dimethylcyclohexylamine as a catalyst, the necessary amount to give a gel time of 45 seconds, an appropriate amount of blowing agent from ■ to ■ in Table 1 below, and polymethylene polyamide. Phenyl isocyanate (MD Kasei■
(Product name: PAP1135) was mixed at a liquid temperature of 20°C,
It was placed in a wooden box measuring 0a+a+ x 200m+a x 200mm and foamed for evaluation. Further, as a comparative example, R-11 was similarly foamed and evaluated.

The amount of foaming agent used is determined when the core density of the foam is 30±2K.
g/m".

The results are shown in Table 2.

[Effects of the Invention] The present invention can effectively reduce the amount of chlorinated fluorinated hydrocarbons such as R-11, which may cause ozone layer depletion, and produce a good foamed synthetic resin. be.

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. In the method for producing a resin, a mixed blowing agent consisting of CCl_2HCF_3 and CCl_2FCH_3 or CCl_2HCF_3, CCl_2F is used as a low-boiling halogenated hydrocarbon blowing agent.
A method for producing a foamed synthetic resin, characterized in that a mixed blowing agent consisting of CH_3 and CCl_3F is used.