JPH01225610A - Preparation of expanded synthetic resin - Google Patents

Abstract

PURPOSE:To prepare a good expanded synthetic resin without causing clouding and foam breaking, by reacting an active hydrogen compd. with a polyisocyanate compd. in the presence of a specified foam stabilizer and a specified foaming agent. CONSTITUTION:An expanded synthetic resin is prepared by reacting an active hydrogen compd. (A) having 2 or more active hydrogen-contg. functional groups capable of reacting with an NCO group (e.g., polyether polyol obtd. by adding an alkylene oxide) with a polyisocyanate compd. (B) (e.g., polymethylenepolyphenyl isocyanate) in the presence of a silicone foam stabilizer (C) and a foaming agent (D). Said stabilizer C is a fluorosilicone foam stabilizer having a fluorine content of 5% or higher and a surface tension of 10-30dyn/cm and said agent D is a foaming agent, at least part of which is 1,1-dichloro-2,2,2- trifluoroethane. As said agent D exhibits high solubility in said compd. A and agent C, a good expanded synthetic resin can be obtd. thereby without causing clouding in the mixed liq. and foam breaking in expanding.

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] Producing 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, a foam stabilizer, and a blowing agent. is widely practiced. Examples of active hydrogen compounds include polyhydroxy compounds and polyamine compounds. As a foam stabilizer, a polydimethylsiloxane-polyalkylene oxide block copolymer, a so-called silicone foam stabilizer, is widely used. Examples of the foamed synthetic resin that can be obtained include polyurethane foam,
Examples include 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. Furthermore, various proposals have been made that other fluorine-containing halogenated hydrocarbons with relatively low boiling points can be used as blowing agents, but with the exception of R-11 and R-12 mentioned above, they are still widely used. It has not yet reached the point where it will be done.

Furthermore, the use of other low-boiling point halogenated hydrocarbon blowing agents such as methylene chloride in place of the fluorine-containing halogenated hydrocarbon blowing agents has also been proposed.

[Problems 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 a mixed component system containing both tends to cause phase separation problems. There was a problem of narrowing the range of usable active hydrogen compounds.

If phase separation occurs in the mixed system with the active hydrogen compound, R-11 with heavy specific gravity will accumulate at the bottom of the storage container and become a heterogeneous mixture, which will disrupt the reaction equivalence with the polyisocyanate compound and cause the normal reaction to occur. Unable to obtain foam. Even if there is no clear separation into two phases, poor solubility tends to lead to poor mixing with the polyisocyanate compound, residual unreacted components, and generation of rough foam called voids during the production of foams by polymerization and foaming.

On the other hand, polydimethylsiloxane-polyoxyalkylene block copolymer, which is a silicone foam stabilizer, has a hydrophilic part and a hydrophobic part, and has the effect of a surfactant.
It has the effect of adjusting the shape of the bubbles in the foam. It is generally believed that the lower the surface tension of a surfactant, the finer the bubbles and the lower the thermal conductivity. The authors conducted various studies to obtain a foam stabilizer with low surface tension, and found that by adding fluorine atoms to the molecules of silicone foam stabilizers, the surface tension can be dramatically lowered and It has been found that this reduces conductivity. However, the addition of fluorine leads to an increase in the hydrophobic portion of the polydimethylsiloxane-polyoxyalkylene block copolymer, which deteriorates the solubility of the halogenated hydrocarbon blowing agent in active hydrogen compounds and This will promote the phenomenon of separation. In our experiments, in general, when the fluorine content exceeds 5%, cloudiness begins to appear in the system liquid containing the active hydrogen compound, catalyst, foam stabilizer, and foaming agent. This cloudiness is a state in which phase separation has begun to occur in minute units. Furthermore, if a foam stabilizer with a high fluorine content is used, foam breakage will occur during foaming. However, fluorosilicone with a fluorine content of less than 5% does not reduce the surface tension sufficiently. For this reason, it has been extremely difficult to use fluorosilicone foam stabilizers. For these reasons, it is desired to develop a blowing agent that has high solubility with active hydrogen compounds and fluorosilicone foam stabilizers.

[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 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 foam stabilizer and a foaming agent, the fluorine content is 5% as the foam stabilizer.
5. Use a fluorosilicone foam stabilizer with a surface tension of 10 to 30 dyn/am, and use a foaming agent at least partially composed of 1,1-dichloro-2,2,2-trifluoroethane. A method for producing a special foam synthetic resin characterized by the following.

1,1-dichloro-2,2 which is a blowing agent in the present invention
, 2-trifluoroethane is a compound with a boiling point of 27.1°C, and this 1,1-dichloro-2,2,2-trifluoroethane has a high solubility in active hydrogen compounds such as polyols and a low temperature in the presence of water. High solubility in active hydrogen compounds and in fluorine-containing halogenated hydrocarbon blowing agents such as R-11 and R-12 and silicone foam stabilizers, and the above-mentioned halogenated hydrocarbon blowing agents and active hydrogen compounds. Problems caused by solubility between the two can be reduced.

Water is often used in combination with the halogenated hydrocarbon blowing agent. Examples of blowing agents other than waterside that can be used in combination include low-boiling halogenated hydrocarbons other than those mentioned above, low-boiling hydrocarbons, and inert gases. 1.1-dichloro-2,
Examples of low-boiling halogenated hydrocarbons other than 2,2-trifluoroethane 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.

1,1-dichloro-2,2,2-trifluoroethane in the present invention can be used alone as well as in combination with other blowing agents.

As shown in L, 1,1-dichloro-2,2,2-trifluoroethane not only has high solubility in active hydrogen compounds or mixtures of active hydrogen compounds and fluorosilicone foam stabilizers; It also has high solubility in other halogenated hydrocarbon blowing agents such as -11 and 112. Therefore, 1,1-dichloro-2,2,2-trifluoroethane has the effect of increasing the compatibility between the two. That is, additives (i.e.,
can be used as a compatibilizer). When 1,1-dichloro-2,2,2-trifluoroethane is used as a compatibilizer, R-11 and To-12 are preferred as blowing agents with low solubility. In addition, the amount used is 1,1-dichloro-2,2,2-trifluoroethane and the halogenated hydrocarbon blowing agent with low solubility. An amount of at least 2% by weight of trifluoroethane, preferably 5 to 100% by weight, especially 15 to 70% by weight, is preferred.

In the present invention, the fluorosilicone foam stabilizer refers to a polydiorganosiloxane-polyoxyalkylene plotter copolymer-based foam stabilizer in which the polydiorganosiloxane block has a fluorine atom. That is, a polydiorganosiloxane block containing a diorganosiloxane unit in which at least one of two monovalent organic groups bonded to a silicon atom is a monovalent organic group containing a fluorine atom, and a polyoxyalkylene block. It is silicone having a block. The polydiorganosiloxane block may consist only of fluorine-containing diorganosiloxane units, or may have other diorganosiloxane units at the 1st position (particularly dimedylsiloxane units).

The polyoxyalkylene block may be bonded to one of the fluorine-containing diorganosiloxane units, but is preferably bonded to a diorganosiloxane unit that does not contain a fluorine atom. A preferred fluorine-containing diorganosiloxane unit is a unit represented by the following formula [1F].

(Si-0)　　　　　　　　・・・[11n’　-Rf Rf: polyfluoroalkyl group having 1 or more carbon atoms.

R1: Alkylene group having 1 to 6 carbon atoms.

8221-valent organic group.

R[ is preferably a perfluoroalkyl group having 1 to 8 carbon atoms, particularly preferably a perfluoroalkyl group having 2 to 6 carbon atoms. As R1, an alkylene group having 1 to 4 carbon atoms is preferable, and an ethylene group is particularly preferable. R2 is -R'-
Suitable are fluorine-containing alkyl groups, alkyl groups, and phenyl groups similar to the Rf group, and preferably an alkyl group having 1 to 4 carbon atoms, particularly a methyl group. Among the units of the above formula H1 in the polydiorganosiloxane block, some R2 may be a polyoxyalkylene block, but preferably,
The polyoxyalkylene block is present in diorganosiloxane units that do not contain fluorine atoms.

In the present invention, the fluorosilicone foam stabilizer has a fluorine content of 5% by weight or more, preferably 10% by weight.
The above are used.

A particularly preferred fluorine content is 20% by weight or more. In addition, the surface tension of the fluorosilicone foam stabilizer is lO~30d
yn/cI111, particularly preferred is lO~20 dyn/am.

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 this as a main component and further containing polyamines. 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. As a polyol,
Examples include polyether polyols, polyester polyols, 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. As the polyether polyol, a polyether polyol obtained by adding a cyclic ether, especially an alkylene oxide such as propylene oxide or ethylene oxide, to a polyhydric alcohol, saccharide, alkanolamine, or other initiator is preferable. It is also possible to use a polyol composition called a polymer polyol or a graft polyol in which fine particles of a polymer are dispersed in a polyether polyol. Polyester polyols include polyhydric alcohols, polycarboxylic acid condensation polyols, and cyclic ester ring-opening polymer polyols. Polyhydric alcohols include ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, glycerin, and trivalent alcohols. Examples include methylolpropane, pentaerythritol, jetanolamine, and triethanolamine. Compounds having two or more phenolic hydroxyl groups include resol-type initial condensates in which phenols are condensed with excess formaldehyde in the presence of an alkali catalyst, and non-aqueous There are benzylic-type initial condensates made by reacting with formaldehyde in the presence of an acid catalyst, and novolac-type initial condensates 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. Typical examples include phenol, cresol, and bisphenol A-rusorcinol. 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 compounds 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, tolylene diisocyanate, diphenylmethane diisocyanate, polymethylene polyphenylisocyanate (common name: 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. 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 applicable to 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 with a hydroxyl group restriction of 200 to 900 and aromatic polyisocyanate compounds. When producing these rigid foams, the halogenated hydrocarbon blowing agent is often used in an amount of 5 to 150% by weight, particularly 20 to 60% by width, based on the active hydrogen compound. It is also possible to use up to 10 fflff1% of water with respect to 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 is 5 to 150% by weight, especially 20 to 60% by weight, based on the active hydrogen compound.
Often used. Furthermore, it is preferable to use 4 to 10% by weight of water in the case of a flexible polyurethane foam, and 0 to 5% by weight in the case of a microcellular elastomer. It is believed that 1,1-dichloro-2.2.2-trifluoroethane in the present invention is also effective in producing foams using other halogenated hydrocarbon blowing agents.

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited to these Examples.

The polyols used in the examples are as follows.

Polyoluminum: Hydroxyl value 32 made by reacting phthalic anhydride with butanediol and then reacting with ethylene oxide.
No. 5 polyether polyol polyol B: Polyol with a hydroxyl value of 315 made by reacting phthalic anhydride and diethylene glycol Polyol C: Polyether polyol with a hydroxyl value of 450 made by reacting metatoluenediamine with ethylene oxide and propylene oxide [ Examples] Table 1 shows the solubility and foaming results of the six foaming agents and silicone foam stabilizers of the present invention in the above-mentioned polyols.

The solubility is determined by adding a solution containing 100 g of polyol, 25 wt. After stirring, each sample was left standing for evaluation.

Book [ C4FeCl1mCt1g (Clls) Si
O2 unit.

[(Clls)*SiO], [CllsR
"SiO" unit.

and (Cll-)sSi end-grouped fluorosilicone (n3 is polyoxyalkylene block)
.

Foaming evaluation was performed as follows.

For 100 parts by weight of polyol, 2 parts of fluoro silicone foam stabilizer, 1 part of water, N% N-dimethylcyclohexylamine as a catalyst, the necessary amount to give a gel time of 45 seconds, and the following halogenation A mixture of a hydrocarbon foaming agent and polymethylene polyphenylisocyanate (trade name PAP1135, manufactured by MD Kasei) were mixed at a temperature of 20° C., and the mixture was placed in a wooden box measuring 200 mm x 200 mm x 200 mm for one foaming evaluation. The amount of the blowing agent used was adjusted so that the foam core density was 30±i kg/m''.
123 is 1. Trichloro2.2.2- represents trifluoroethane.

■ R-11100% ■ R-1195%, R-1235% ■ R-1190%, R-12310% ■ R-118
0%, R-12320%■ R-1150%, R-12
34) The criteria for determining O% are as follows.

<About solubility> O: Transparent, homogeneous liquid △: Cloudy (state where phase separation has occurred in a minute range) B: The cell shape is uneven and some voids are observed C: There is uneven mixing and voids are seen everywhere Table 1 [Effects of the Invention] The halogenated hydrocarbon blowing agent in the present invention is active hydrogen Fluorosilicone foam stabilizers with high solubility in compounds and high fluorine content; Fluorosilicone foam stabilizer with high fluorine content and R-11
It has an excellent effect of solving problems such as phase separation of a foaming agent with low solubility from active hydrogen compounds such as and fluorosilicone foam stabilizers with high fluorine content.

Claims (1)

[Claims] 1. 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 foam stabilizer and a foaming agent. In this method, a fluorosilicone foam stabilizer having a fluorine content of 5% or more and a surface tension of 10 to 30 dyn/cm is used as a foam stabilizer, and at least a portion of the foam stabilizer is 1,1-dichloro-2,2,2. - A method for producing a foamed synthetic resin, characterized in that a foaming agent is trifluoroethane. 2. As a foam stabilizer, fluorine content is 10% or more, surface tension is 10
2. The method of claim 1, wherein ~20 dyn/cm of fluorosilicone foam stabilizer is used. 3. The method according to claim 1, wherein 1,1-dichloro-2,2,2-trifluoroethane and water and/or another low-boiling halogenated hydrocarbon blowing agent are used together as the blowing agent. 4. The foamed synthetic resin is a rigid polyurethane foam.
The method according to claim 1.