JPH03743A - Preparation of foamed synthetic resin - Google Patents

Abstract

PURPOSE:To reduce the possibility of destroying the ozone layer which has become an issue in chlorofluorohydrocarbons which have been hitherto used as the foaming agent by using a specified compd. in preparing a foamed synthetic resin such as a polyurethane foam. CONSTITUTION:In a method for preparing a foamed synthetic resin by reacting an active hydrogen compd. contg. 2 or more active hydrogen functional groups reactive with an isocyanate group with a polyisocyanate compd. in the presence of a foaming agent of a low b.p. org. compd., a polyfluoro-compd. contg. sulfur atom is used as the foaming agent. Examples of the polyfluoro-compd. include perfluoro-compd. such as CF3SF5, SF5CF2SF5 and CF3SF4CF3, aliph. polyfluoro- compd. such as C2F2HSF5, and cyclic compd. such as perfluorothioethers and perfluorothiofurans.

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-
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.

[Problem 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. The chlorinated fluorinated hydrocarbons used as blowing agents are thought to be decomposed by the action of ultraviolet rays, etc., and the decomposed products 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, 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 that have been made to solve the above-mentioned problems.

2 active hydrogen-containing functional groups that can react with isocyanate groups
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 organic compound blowing agent, characterized in that a polyfluoro compound containing a sulfur atom is used as the blowing agent. A method for producing foamed synthetic resin.

Examples of the polyfluoro compound containing a sulfur atom in the present invention include CF@5Fll and SF5CFm5Fs.

Perfluoro compounds such as cps5p<cps, C, F,
Aliphatic polyfluoro compounds such as HSFs can be mentioned.

In addition, cyclic substances such as perfluorothioethers and perfluorothiofurans are also included.

Since the fluorine-containing compound that is the blowing agent in the present invention is a compound that does not have a chlorine 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 fluorine-containing compound blowing agents in the present invention may be used alone or in combination with other blowing agents. In particular, water is often used in combination with the fluorine-containing compound blowing agent. Examples of blowing agents other than waterside 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. Although R-11 and R-12 themselves may cause ozone layer destruction, their usage can be reduced by using them in combination with the blowing agent in the present invention. 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 condensate) can also be used. Polyols include polyether polyols, polyester polyols,
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 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. The molecular weight of these initial condensates is preferably 200 to 1oooo. 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, and bisphenol A-rusorcinol. Further, the formaldehyde is 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 zo-iooo 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 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 1 parts by weight, particularly 1 to 5 parts 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: Polyether polyol with a hydroxyl value of 420 made by reacting glycerin with propylene oxide Polyol B: 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 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, N%N-dimethylcyclohexylamine as a catalyst in an amount necessary for a gel time of 45 seconds, an appropriate amount of the blowing agent shown below, and polymethylene polyphenylisocyanate (MD Kasei (trade name: PAP1135) was mixed at a liquid temperature of 20°C, and 200-m
The mixture was placed in a wooden box measuring 200 mm x 200 wm 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 1.

The criteria for judgment are as follows.

○＋ Equivalent to R-11 or higher △: Slightly inferior to R-11 X: Inferior to R-11 Table 1 Foaming agent; C2F, HSFs Table 2 Foaming agent; CF, SF, CF.

[Effects of the Invention] According to the present invention, a good foamed synthetic resin can be produced without substantially using chlorinated fluorinated hydrocarbons such as R-11, which may cause ozone layer depletion.

Claims (1)

[Claims] 1. In a method for producing a foamed synthetic resin 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 organic compound blowing agent, the blowing agent 1. A method for producing a foamed synthetic resin, the method comprising using a polyfluoro compound containing a sulfur atom.