JPH02123142A - Production of polyurethane foam - Google Patents

Abstract

PURPOSE:To produce a polyurethane foam excellent in respective performances, such as heat conductivity, by using a fluorine-containing silicone-based foam stabilizer as at least one component of a foam stabilizer. CONSTITUTION:(A) A polyether polyol obtained by adding an alkylene oxide to an active hydrogen compound (e.g., toluenediamine) is reacted with (B) a polyisocyanate using (C) a polysiloxane-based block copolymer (preferably polydimethylsiloxane-based copolymer) having both fluorine-containing groups (preferably fluorine-containing alkyl or alkenyl, more preferably trifluoromethyl- containing alkyl or alkenyl, especially 3,3,4,4,4-pentafluoro-n-butyl) and polyoxyalkylene chain (preferably polyoxyethylene oxypropylene copolymer chain) as at least one component of a foam stabilizer in the presence of a catalyst and a foaming agent to produce a polyurethane foam.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a method for producing polyurethane foam obtained by reacting a polyol and a polyisocyanate compound, and particularly relates to a method for producing polyurethane foam using a specific foam stabilizer. The present invention relates to a manufacturing method.

[Prior art] Rigid foams such as rigid polyurethane foam and urethane-modified polyisocyanurate foam have a relatively high water resistance of 1'!
? It is produced by reacting a basic polyol and a polyisocyanate compound in the presence of a catalyst, blowing agent, foam stabilizer, etc.

The ratio of polyisocyanate compound to 1 equivalent of polyol (commonly referred to as isocyanate index) is approximately 1
．． The rigid foam obtained by reacting at a ratio of 3 or less is a rigid polyurethane foam, and a polyisocyanate compound is added in large excess (usually an incyanate index of about 1.5 or more) to the polyol in the coexistence of an isocyanate trimerization catalyst. The hard foam obtained by the reaction is urethane-modified polyisocyanurate foam. The average hydroxyl value of the polyol used is often 3011~
Polyols having average hydroxyl values in the range of 700 or outside this range may be used. The polyol may be a mixture of two or more types of polyols, in which case some of the polyols may have a hydroxyl value outside the above range. That is, the average hydroxyl value of the mixed polyol is preferably within the above range, and the hydroxyl value of each individual polyol is not particularly limited.

In the production of rigid foams, the selection of foam stabilizers is one of the important factors to obtain good foams. It is believed that the role of the foam stabilizer is to stabilize the cells, adjust the cell diameter, and improve the mutual dispersibility of raw materials such as polyols, polyisocyanate compounds, and blowing agents. Various types of foam stabilizers are used depending on the purpose. For example, foam stabilizers for flexible polyurethane foams and foam stabilizers for rigid polyurethane foams are generally used with different structures. One of the compounds widely used as foam stabilizers for rigid foams is polydimethylsiloxane having polyoxyalkylene chains as block chains, ie polydimethylsiloxane-polyoxyalkylene-block copolymers. In addition, the terminal group of the polyoxyalkylene chain is usually a methyl group or an allyl group, and the polyoxyalkylene chain is composed of poly(oxyethylene/oxypropylene).
The performance of the foam stabilizer, which is often a chain, changes depending on its molecular weight and structure, and also changes depending on the terminal group of the polyoxyalkylene button. Use of a block copolymer (ethylene/oxypropylene) as a foam stabilizer for the production of rigid polyurethane foam (Japanese Patent Application Laid-Open No. 1983-1999)
It is known to use a polysiloxane block copolymer having an aromatic nucleus at the end of a polyoxyalkylene chain.

However, conventional polydimethylsiloxane-based foam stabilizers have a limited ability to lower the surface tension of the reaction system, and there are also limits to the performance, especially thermal conductivity, of the foams obtained using them. It is difficult to fully satisfy the required performance.

[Problems to be Solved by the Invention] The present invention attempts to solve the above-mentioned drawbacks of the prior art, and by lowering the surface tension of the reaction system, it is possible to improve the foam obtained using the reaction system. The object of the invention is to provide a manufacturing method which allows foams to be obtained that are superior to those of the prior art in terms of performance, in particular thermal conductivity.

[Means for Solving the Problems] The present invention has been made to solve the above-mentioned problems, and is made by reacting a polyol and a polyisocyanate compound in the presence of a catalyst 1 blowing agent, a foam stabilizer, etc. A method for producing polyurethane foam, characterized in that a polysiloxane block copolymer having both a group having a fluorine atom and a polyoxyalkylene chain is used as at least one component of the foam stabilizer. It provides:

The foam stabilizer in the present invention is a compound having a structure similar to a conventional one.

1- In the general formula (1), R is a lower alkyl group, a cyclo-lower alkenyl group, a phenyl group, etc., and each R may be different. Preferred R is a methyl group, and in particular, substantially all A compound in which R is a methyl group is preferred,
l(+ is an alkylene group having 2 to 4 carbon atoms, and (O
R')k, that is, the polyalkylene chain is preferably a polyoxyethylene group or a random or block copolymer chain of an oxyethylene group and an oxypropylene group. A is a divalent bonding chain, such as an alkylene group or It is a divalent group produced by the reaction of X and y, which will be described later, and each A may be different.

A is particularly preferably an alkylene group, the number of carbon atoms is preferably 8 or less, especially 6 or less, B is a lower alkyl group,
These are lower alkenyl groups, phenyl groups, etc., and each B may be different.

D is a group containing a fluorine atom. Sentence and m,! : Although n is an integer, the average value may not be an integer.

m in one molecule is suitably 0.6 to 30 on average, particularly preferably i, o-io, n in one molecule is on average 0
．． 5 to 60 is suitable, particularly 2 to 20 is preferable, 1
The number in the molecule is preferably about 5 to 60 on average, and preferably about 10 to 30. l/+o is about 1 to -12, preferably about 100 or less. More preferable l/m is about 2
．． 0 to 20, particularly preferably about 2.0 to IO. The molecular weight of the compound represented by the above formula (1) is approximately 1000 to 3
10,000 to 10,000 is appropriate, and about 2,000 to 10,000 is particularly preferred. The polyoxyalkylene chain is broken by the polysiloxane (Si-0), (X: hydrogen atom or functional group) and Y→OIt'+TB (Y: a functional group that can react with the 5i-X group). Formed by reaction. A typical combination is X or a hydrogen atom, Y or an allyl group, and a 25"g alkenyl group. If Y is an allyl group, A is a trimethylene group. Also, if Y is a hydrogen atom, X is a hydrogen atom. atoms, halogen atoms, hydroxyl groups, alkyl groups having a functional group capable of bonding to hydroxyl groups (for example, carboxylic acid groups, epoxy groups, incyanate groups, vinyl groups, ester groups, etc.), and other governmental groups.

As mentioned above, D refers to a large group containing fluorine atoms, but in the present invention, when the foam stabilizer is dissolved or mixed in the polyol in the same proportion as the reaction/foaming formulation, the surface of the solution or mixture is Tension: Preferably, it is 1 Odyne/cm or less. Further, in the present invention, it is more preferable that the group having a fluorine atom is an alkyl group or an alkenyl group having a fluorine atom because of the form properties.

In the present invention, it is more preferable that D is an alkyl group or alkenyl group having a trifluoromethyl group, and D is a 3,3,4,4,4-pentafluoro-n-butyl group. This is even more preferred.

Materials that can be used in the present invention in combination with the above foam stabilizers include all commonly used materials known to the polyurethane industry. In practice, active hydrogen compounds include polyols and/or polyamines having 1 to 8 hydroxyl groups and/or 1 to 4 amino groups, such as polyether polyols, polyester polyols, polythioether polyols, alkanolamines, polyether Known materials commonly used in the polyurethane industry, such as polyamines and polyalkylene polyamines, can be used. However, polyether polyols are generally used as the main component. Polyether polyols are generally made by adding 1 to alkyleneoxy to an active hydrogen compound.

Examples of active hydrogen compounds include water, catechol, resorcinol, hy-1-roquinone, orcinol, 2,2-bis(p-hydroxyphenyl)furopane, bis(p-hydroxyphenyl)methane, glycerin, sorbitol,
Trimethylolpropane, 1,2,6-hexandriol, pentaerythritol, sucrose, methylglucoside, tetramethylolcyclohexanol,
3,3.5-tris(hydroxymethyl)-5-methyl-4-hydroxytetrahydropyran, :l, :1
, 5.5-tetrakis(hydroxymethyl)-4-hydroxytetrahydropyran, 2.2-bis(hydroxyphenyl)ethanol, pyrogallol, phloroglycitur, 1.1.2-tris(hydroxyphenyl)ethane, 1,1 .3- Tris(hydroxyphenyl)propane, 1,1. :1,3-tetrakis(hydroxy-
3-methylphenyl)propane, 1,1,4.4tetrakis(hydroxyphenyl)butane, ■, 4-butanediol, 1,6-hexanediol, monoethanolamine, jetanolamine, triethanolamine,
Ethylenediamine, diethylenetriamine, 0-toluenediamine, m-toluenediamine, p-toluenediamine, 4,4゛-diaminodiphenylmethane, phenol-aldehyde condensates, p-alkyl substituted phenol-aldehyde condensates, and other polyhydric There are Mannich adducts which are condensates of phenolic compounds and phenols and/or aromatic amines, alkanolamines or polyamines, and aldehydes.

Alkylene oxides are generally ethylene oxide,
Propylene oxide is used or else 1,2-
Butylene oxide, 4.4.4-trichloro-1,2
-Butylene oxide, epichlorohydrin, glycidyl ethers, di-glycidyl esters, glycidyl alcohols, diglycidyl ethers, etc. may be used. Examples of polyester polyols include:
Polyester polyols having aromatic polycarboxylic acid residues such as phthalic acid and polyhydric alcohol residues, linear high molecular weight polyesters (e.g. polyethylene terephthalate), and by-streams and residues generated during the production of high molecular weight polyesters. These include partial hydrolysates and transesterification products of these with active hydrogen compounds. Furthermore, polyester polyols such as polyols obtained by adding alkylene oxide to polyester polyols can be used. The polyols described above can not only be used alone, but also two or more types may be used in combination.

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: flute MDI),
Examples include polyisocyanates such as xylylene diisocyanate, isophorone diisocyanate, and hexamethylene diisocyanate, as well as prepolymer-type modified products, isocyanurate-modified products, and urea-modified products thereof.

When reacting active hydrogen compounds and polyisocyanate compounds, the use of catalysts is usually required. As the catalyst, a metal compound catalyst such as an organic tin compound or a tertiary amine catalyst such as triethylenediamine, which promotes the reaction between an active hydrogen-containing group and an isocyanate group, is used. In addition, a catalyst for reacting isocyanate groups such as carboxylic acid metal salts with each other is used depending on the situation.

Other compounding agents used in the production process include fillers, stabilizers, blue agents, flame retardants, and the like.

Using these raw materials, polyurethane foam, urethane-modified polyisocyanurate 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 particularly focuses on rigid polyurethane foam, which is often used as a heat insulating material.
It is particularly useful in the production of urethane-modified polyisocyanurate foams and other rigid foams. 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 100 and aromatic polyisocyanate compounds. When manufacturing these hard foams, the amount of the fluorine-containing silicone foam stabilizer used in the present invention is 0.01 to 20% based on the active hydrogen compound.
Weight % is suitable, especially 0.1 to 7.0 weight %.

In addition, it is also possible to use a silicone foam stabilizer that does not contain fluorine or other surfactants.

On the other hand, in the case of flexible polyurethane foam, semi-rigid polyurethane foam, and microcellular elastomer, 1
The fluorine-containing silicone foam stabilizer used in the present invention is preferably used in an amount of 0.01 to 20% by weight based on the active hydrogen compound. There are no limitations.

[Example] The foam stabilizers used in the examples are as follows.

Foam stabilizer (O: Compound having a structure represented by the following general formula ■): A compound having a structure represented by the general formula A above, in which each unit of a C is a block body in which each wheel position is polymerized. , what exists.

■: ■: (5): (6): e e ■ Foaming evaluation of the fluorine-containing silicone foam stabilizer of the present invention was conducted for the following formulations.

Polyether polyol with a hydroxyl value of 450 gKOH/g made by reacting toluenediamine with propylene oxide and ethylene oxide 100 parts by weight Foam stabilizer
Variable l/1.4 diazabicyclo[2
,2,2] Octane (33% DPG solution) 2. Otr trichlorofluoromethane 40/crude 140
1 115 7/For foaming, mix the raw materials listed above at a liquid temperature of 20°C, 200a + m x 20
The test was carried out by placing the sample in a 0 mm x 200 nm wooden box and causing it to foam. In addition, as a comparative example, similar foaming was performed using a foam stabilizer that does not contain fluorine and evaluated.

The results are shown in Table 1.

[Effects of the Invention] According to the present invention, a urethane foam with excellent performance can be produced by using a silicone foam stabilizer having a fluorine atom.

1.1'lj人()l'J! l! , t) −11ξ
Detective 1]・1” Kote Itome Ne Yusakichi January 16, 1990

Claims (6)

[Claims] (1) In a method for producing polyurethane foam by reacting a polyol and a polyisocyanate compound in the presence of a catalyst, a blowing agent, a foam stabilizer, etc., at least one component of the foam stabilizer includes a group having a fluorine atom and a polyurethane foam. A method for producing a rigid foam characterized by using a polysiloxane block copolymer having oxyalkylene chains. (2) The method according to claim 1, wherein the polysiloxane block copolymer is a polydimethylsiloxane block copolymer. (3) The method according to claim 1, wherein the group having a fluorine atom is an alkyl group or an alkenyl group having a fluorine atom. (4) The method according to claim 1, wherein the group having a fluorine atom is an alkyl group or an alkenyl group having a trifluoromethyl group. (5) The method according to claim 1, wherein the group having a fluorine atom is a 3,3,4,4,4-pentafluoro-n-butyl group. (6) The method according to claim 1, wherein the polyoxyalkylene chain comprises a polyoxyethylene oxypropylene copolymer chain.