JPH02263841A - Production of expanded synthetic resin - Google Patents

Abstract

PURPOSE:To obtain the subject 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 CCl3F and CCl2FCH3 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. 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 CC1,F (R-11) is mainly used. Further, water is usually used in combination with R-11. 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.

[Problem to be solved by the invention] R-11, which has been widely 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, and a normal foam cannot be obtained.Even if there is no clear separation into two phases, the poor solubility is caused by the reaction between the polyisocyanate compound and the polyisocyanate compound. This tends to lead to poor mixing, residual unreacted components, and the generation of coarse bubbles called voids.Furthermore, R-11 and R-12 remain undecomposed because they are chlorinated fluorinated hydrocarbons that are extremely stable in the atmosphere. It is now thought that it may reach the ozone layer above the atmosphere, where it is decomposed by the action of ultraviolet rays, and the decomposition products destroy the ozone layer.

Therefore, in place of such R-11 and R-12, it is desired to develop a blowing agent that does not have the problem of solubility with active hydrogen compounds and has less risk of ozone layer depletion.

[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 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, the low boiling point halogenated hydrocarbon blowing agent includes CC1, F and CGI
□FC)1. A method for producing a foamed synthetic resin, characterized by using a mixed foaming agent consisting of:

CCI□FCHs, which is a component of the blowing agent in the present invention
(R-141b) is a compound with a boiling point of 32° C., and since it is a fluorinated hydrocarbon having a hydrogen atom in the molecule, 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.

In addition, R-141b has solubility in active hydrogen compounds such as polyols, accumulates solubility in active hydrogen compounds in the presence of water, and dissolves in fluorine-containing halogenated hydrocarbon blowing agents such as R-11 and R-12. It has high properties and can reduce the problems caused by the solubility between the halogenated hydrocarbon blowing agent and the active hydrogen compound.

The mixing ratio of the mixed blowing agent in the present invention is R-117R
-141b=2-80% by weight/20-98% by weight, preferably 10-60% by weight/40-90% 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 blowing agents other than waterside that can be used in combination include, for example, the current blowing agent R-12, other low-boiling halogenated hydrocarbons, low-boiling hydrocarbons, and inert gases.

Although R-141b alone is weakly flammable, R-1
1 can be made nonflammable.

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. In particular, compounds having two or more hydroxyl groups, mixtures thereof, or mixtures containing the same as a main component and further containing polyamines are preferable. As compounds having two or more hydroxyl groups, widely used polyols are preferable, but two or more hydroxyl groups are preferable. A compound having a phenolic hydroxyl group (for example, a phenol resin initial clamp) can also be used. Polyols include polyether polyols, polyester polyols,
Examples include polyhydric alcohols and diethylene polymers containing hydroxyl groups. In particular, the polyether polyols are preferably composed of one or more polyether polyols, or are preferably used in combination with polyester polyols, polyhydric alcohols, polyamines, alkanolamines, and other active hydrogen compounds. Preferred are polyether polyols 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 precondensates made by reacting excess phenols with formaldehyde in the presence of an acid catalyst, and novolac-type precondensates made by reacting excess phenols with formaldehyde in the presence of an acid catalyst. 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. 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, 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 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 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, 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 a hard urethane foam, it is preferable to use 0 to 10% by weight of water, and in the case of a 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.

Polyoluminum: Hydroxyl value 32 made by reacting phthalic anhydride with butanediol and further reacting with ethylene oxide.
Polyether polyol polyol b of No. 5 = Polyether polyol with a hydroxyl value of 315 made by reacting phthalic anhydride and diethylene glycol Polyol C: Polyether polyol with a hydroxyl value of 460 made by reacting metatoluenediamine with ethylene oxide and propylene oxide Foaming evaluation is It was done 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■
Mix the product name PAPI135) at a liquid temperature of 20°C, and
0mm x 200+++n x 200mm (7)
It was placed in a wooden box and foamed for evaluation. Further, as a comparative example, R-11 was similarly foamed and evaluated. The amount of foaming agent used is based on the foam core density of 30±2 kg/m.
It was adjusted so that

The results are shown in Table 2.

The criteria for judgment are as follows.

Better than R-11 Equal to R-11 Slightly inferior to R-11 Inferior to R-11 [Effects of the Invention] The present invention eliminates the use of chlorinated fluorinated hydrocarbons such as R-11, which may cause ozone layer depletion. It is possible to effectively reduce the amount, solve the problem of poor solubility of the active hydrogen compound and the blowing agent, and produce a good foamed synthetic resin.

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 a mixed blowing agent consisting of CCl_2F and CCl_2FCH_3 as a low-boiling halogenated hydrocarbon blowing agent.