JPH0314811A - Foam breaker and its use - Google Patents

Abstract

PURPOSE:To prepare a foam breaker which is used for producing a polyurethane foam and gives a good molded item with a short demolding time by using an acidic compd. (salt) having a fluoroalkyl group as the effective component. CONSTITUTION:A foam breaker for producing a polyethane foam is prepd. by using an acidic compd. or a salt thereof contg. a fluoroalkyl group as the effective component. As said fluoroalkyl group, a 3-17C highly fluorinated polyfluoroalkyl group is pref. and examples of said acidic compd. include a polyfluorocarboxylic acid and polyfluorosulfonic acid. An integral skinned polyurethane foam molded item can be produced with a short demolding time, i.e., with a fast molding cycle, by reacting a high-mol.wt. polyol, a polyisocyanate, a crosslinker, etc., in a mold, in the presence of said acidic compd. (salt).

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a method for producing polyurethane foam with an integral skin using a specific foam-breaking agent, and the specific foam-breaking agent for producing polyurethane foam. It is.

[Prior art] Polyurethane foam molded products with integral skins have a skin layer that is integrally formed with the foam layer, so they have excellent elasticity and tactility, so they are suitable for automotive applications such as steering wheels, crash pads, headrests, and armrests. It is widely used for interior parts. Recently, opportunities for use have expanded to fields other than these, such as housings for office equipment and furniture.

Polyurethane foam with integral skin uses a high molecular weight polyol, a crosslinking agent, and a polyisocyanate as reaction raw materials, which are reacted and cured in a mold in the presence of a catalyst, blowing agent, foam stabilizer, and other auxiliary agents. Manufactured by Molding is performed by injecting a mixture of the above-mentioned raw materials into a mold, and a low-pressure foaming machine or a high-pressure foaming machine (RIM machine) is used for mixing and injecting the raw materials. Although it is advantageous to use a high-pressure foaming machine to shorten the molding cycle of molded products, it is considered necessary to consider raw materials in order to further shorten the molding cycle.

[Problems to be Solved by the Invention] In order to shorten the cycle required for polyurethane foam molded articles with integral skins, it is possible to select highly reactive raw materials and optimize the type and amount of catalyst used. However, the inventors of the present invention considered that there is a need for other measures to shorten the demolding time of molded products. If demolding is accelerated, deformation of the molded product, ie, swelling or shrinkage of the molded product after demolding, is likely to occur. The cause of this is of course insufficient strength of the integral skin, but it is also thought that gas release within the molded product is insufficient. That is, it is presumed that this is due to expansion of the molded product due to the foaming gas being trapped in closed cells and an increase in the internal pressure of the molded product, or cooling of the foaming gas, resulting in a decrease in the molded product internal pressure, causing the molded product to contract. To solve this problem, it is necessary to communicate the core form. It is conceivable to use a so-called foam-breaking agent to make the core foam open. Silicone compounds and oils such as polybutene are used as foam-breaking agents for general polyurethane foams. However, in the production of polyurethane foam with integral skin, conventional foam-breaking agents are not sufficient, and a foam-breaking agent with higher performance is required.

[Means for Solving the Problems] The present invention relates to a foam-breaking agent for producing polyurethane foam and a method for producing polyurethane foam with integral skin using the same.

A foam-breaking agent for producing polyurethane foam made of an acidic compound having a fluoroalkyl group or a salt thereof.

With an integral skin characterized by reacting a high molecular weight polyol, a crosslinking agent, and a polyisocyanate in a mold in the presence of a catalyst, a blowing agent, a foam stabilizer, and an acidic compound having a fluoroalkyl group or a salt thereof. Manufacturing method for polyurethane foam molded products.

The acidic compound having a fluoroalkyl group, which is a foam-breaking agent in the present invention, is a compound having a fluoroalkyl group and an acidic group, and the salt thereof is a salt of the acidic compound and a basic compound. A fluoroalkyl group refers to an alkyl group having a fluorinated carbon atom, and two or more fluorine atoms may be present, and the alkyl group has one or more carbon atoms, preferably 3 to 25 carbon atoms. Preferably, the highly fluorinated polyfluoroalkyl group (hereinafter referred to as Rf) is or Rf-R- (R is an alkylene group).

Highly fluorinated means that 80 to 100% of the hydrogen atoms bonded to carbon atoms are replaced with fluorine atoms, and the remaining hydrogen atoms are further replaced with atoms other than fluorine atoms such as chlorine atoms. May be replaced. Rf may be straight or branched, and has 1 to 21 carbon atoms. Particularly preferably 3 to 17. R preferably has 1 or more carbon atoms, particularly 2 to 8 carbon atoms. However, the number of carbon atoms in R is preferably smaller than the number of carbon atoms in Rf. Furthermore, a polyoxyalkylene group having a fluorine atom instead of R can be linked to the Rf group, and the number of carbon atoms in this fluorinated (poly)oxyalkylene group may be larger than the number of carbon atoms in the Rf group. The Rf+R← group may be bonded directly to the acidic group or may be bonded to the acidic group via some bonding group.

Two or more acidic groups may exist in the acidic compound, but
There is usually one. Examples of acidic groups include carboxylic acid groups, sulfonic acid groups, thiocarboxylic acid groups, phosphoric acid residues, and phosphorous acid residues. Preferred are carboxylic acid groups, sulfonic acid groups, and phosphoric acid residues, with phosphoric acid residues being particularly preferred. Specific acidic compounds include polyfluorocarboxylic acids, polyfluorosulfonic acids, phosphoric acid monoesters and diesters of polyfluoroalcohols, and mixtures thereof. Most preferably, Rf+R}
These are phosphoric acid monoesters, diesters of polyfluoroalcohols represented by -OH, and mixtures thereof.

The above acidic compound can be used as a foam-breaking agent, but
If the amount of the acidic compound is large, it may affect the organometallic catalyst for producing polyurethane foam, so it is preferable to use the acidic compound in the form of a salt with a basic compound. As the basic compound, alkali metal compounds, alkaline earth metal compounds, and other basic metal compounds can be used, but amines are preferable for the same reason as above. The amines include primary amines, secondary amines,
These include amines, tertiary amines, and quaternary ammoniums. These amines may be monofunctional or polyfunctional. Of course, it may have other functional groups such as a hydroxyl group. Therefore, the same amines as those used as crosslinking agents described below can also be used. Similarly, amines similar to the tertiary amines often used as catalysts for the production of polyurethane foams can also be used. Examples of amines other than the amines described below as crosslinking agents include alkyl amines, N-alkyl amines,
Examples include N-alkyl-substituted alkylene diamines, polyalkylene polyamines, other aliphatic amines, alicyclic amines such as cyclohexylamine, aromatic amines such as aminobenzene and pendylamine, and heterocyclic amines such as morpholine. . Additionally, amines of higher molecular weight than the crosslinking agent can also be used. Salts of the acidic compounds containing quaternary ammonium ions such as tetraalkylammonium ions can also be used. The amount of the foam-breaking agent used in the present invention is 0.00 parts by weight per 100 parts by weight of the high molecular weight polyol (including polymer decomposition polyol) described below. Ol~
5 parts by weight are preferred, especially 0.05 to 2 parts by weight. However, in the case of a salt, a high molecular weight basic compound is also used, so the amount used above is calculated excluding the amount of the base.

The specific foam-breaking agent in the present invention is suitable for producing polyurethane foam with an integral skin. The main reaction raw materials for producing polyurethane foam with an integral skin (hereinafter referred to as integral foam) are a high molecular weight polyol, a crosslinking agent, and a polyisocyanate. In addition, relatively small amounts of the auxiliary agents described below are often used.

The high molecular weight polyol is preferably a high molecular weight polyol having a hydroxyl value of 80 or less (molecular weight per hydroxyl group of about 100 or more) and an average number of hydroxyl groups per molecule of 1.8 or more, and a mixture of two or more thereof. More preferable hydroxyl value is 5~
60, especially 20-45. The number of hydroxyl groups per molecule is more preferably 2 to 4, particularly 2 to 3. As the high molecular weight polyol, high molecular weight polyols that are commonly used as raw materials for polyurethane foam, such as polyoxyalkylene polyols and polyester polyols, can be used, and polyoxyalkylene polyols are particularly preferred. The polyoxyalkylene polyol is preferably one containing mainly oxybrobylene groups or oxybutylene groups, and more preferably one having a smaller amount of oxyethylene groups. Although the oxyethylene group may be present in the polyoxyalkylene chain in a random or block form, it is particularly preferable that the oxyethylene group be present at the terminal of the polyoxyalkylene chain because a highly reactive hydroxyl group is generated. Particularly preferably, 5 to 40% by weight at the end of the molecular chain,
In particular polyoxypropyleneoxyethylene polyols having 8 to 25% by weight of oxyethylene groups.

The high molecular weight polyols described above may be used in combination with small amounts of other high molecular weight active hydrogen compounds and may also contain other components such as fillers. A typical example of the latter is a polymer-decomposed polyol, also called a polymer polyol. This polymer decomposition polyol uses a high molecular weight polyol as a fraction medium,
This is a dispersion of fine polymer particles containing fine polymer particles as a dispersion with good dispersion stability.

Polymer particles include addition polymer particles and condensation polymer particles, which are produced by polymerizing polymer raw materials such as monomers in a dispersion medium, and by blending separately produced polymer particles with high molecular weight polyol. Manufactured by. The content of polymer fine particles is usually 5 to 45% by weight. Moreover, even if it is a polymer decomposition polyol obtained by polymerizing a polymer raw material in a high molecular weight polyol, it can be diluted by adding a high molecular weight polyol afterwards.

As the high molecular weight polyol for the dispersion medium of the polymer-decomposed polyol, a polyoxyalkylene polyol having the above-mentioned hydroxyl value and number of hydroxyl groups is preferable. Furthermore, the hydroxyl value of the polymer decomposition polyol is lower than the hydroxyl value of the high molecular weight polyol as the decomposition medium in accordance with the amount of polymer fine particles. In the present invention, the amount of polymer fine particles of the polymer-decomposed polyol (which may be a diluted product) is preferably 1 to 30% by weight. Furthermore, a high molecular weight polyol blended with inorganic fine particles such as silica fine particles instead of polymer fine particles can also be used.

The crosslinking agent is a compound having a molecular weight of 300 or less and having a total of two or more hydroxyl groups and/or primary or secondary amino groups, or a mixture of two or more thereof. Especially molecular weight 200
The following compounds are preferred. The number of functional groups is preferably 2 to 3, particularly 2. However, the amines used as the basic compound for the foam-breaking agent are not limited thereto.

Examples of crosslinking agents include polyhydric alcohols, alkanolamines, and polyamines, and alkylene oxide adducts of these can also be used as long as they have a low molecular weight. Specifically, for example, ethylene glycol, diethylene glycol, dipropylene glycol, 1,4-butanediol, neobentyl glycol, 1,6-hexanediol, glycerin, bisphenol A-alkylene oxide adduct, monoethanolamine, diethanolamine , triethanolamine, diisopropanolamine, triisopropanolamine, ethylenediamine,
Propylene diamine, diaminocyclohexane, isophorone diamine, diaminobenzene, toluene diamine,
Examples include diphenylmethanediamine and xylylenediamine. Further, the above-mentioned alkanolamines, polyamines, primary monoamines, and alkylene oxide adducts thereof can be used as basic compounds for the foam-breaking agent. The amount of crosslinking agent used is 1 part of the high molecular weight polyol
0.4 to 15 parts by weight, particularly preferably 1 to 8 parts by weight.

The polyisocyanate is an aromatic, aliphatic, or alicyclic compound having two or more isocyanate groups, and aromatic polyisocyanates are particularly preferred. Specific examples include tolylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, toridine diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xynolene diisocyanate, and modified products thereof. Examples of modified products include brepolymer-type modified products, carbodiimide-modified products, and nurate-modified products. The isocyanate content of the modified product is preferably 10% by weight or more, particularly 16% by weight or more. Preferably diphenylmethane diisocyanate, especially 4,
4'-diphenylmethane diisocyanate and its modified products are used. The amount of polyisocyanate used is 0.8 to 1.3 equivalents per equivalent of other reactive raw materials,
Particularly preferred is 0.95 to 1.2 equivalents.

The production of integral foam usually requires a catalyst, a blowing agent,
It is necessary to use auxiliary agents such as foam stabilizers. 3 as a catalyst
A tertiary amine catalyst, an organometallic compound such as an organotin compound, or another catalyst for producing polyurethane foam may be used alone or in combination, with tertiary amine catalysts being particularly preferred. As the blowing agent, water or a low-boiling organic compound is used, but in the case of integral foam, the amount of water used is small or substantially not used compared to the production of ordinary polyurethane foam. Typical examples of low-boiling organic compounds include low-boiling hydrocarbons and halogenated hydrocarbons.

As the halogenated hydrocarbon, chlorofluorocarbons such as trichlorofluoromethane, which have been widely used in the past, can be used, but there is a problem with ozone, and it is preferable to use fluorocarbons, methylene chloride, etc., which have fewer problems with ozone. Silicone compounds are widely used as foam stabilizers, and the use of silicones is also preferred in the present invention. As the silicone, diorganoborisiloxane or a block copolymer of diorganoborisiloxane and polyoxyalkylene is preferable. High molecular weight polyol l0
The amount of each auxiliary agent to be used is not particularly limited, but the amount of the catalyst is 0.0 parts by weight. Ol ~ 5 parts by weight, blowing agent 3 ~
20 parts by weight, and the foam stabilizer is 0.1 to 5 parts by weight. In addition, various auxiliary agents can be optionally used, and examples of auxiliary agents other than those mentioned above include colorants, flame retardants, ultraviolet absorbers, antioxidants, light stabilizers, and fillers.

The integral foam molded article is preferably molded by a method in which a reactive mixture is injected into a mold using a high-pressure foaming machine (ie, a reaction injection molding method). The high-pressure foaming machine is preferably a type that mixes two normal liquids, one of which is
The liquid used is polyisocyanate, and the other liquids are a mixture of all raw materials other than polyisocyanate. In some cases,
It is also possible to form a reactive mixture of three components in total and inject it, including a catalyst or a foam-breaker (usually dispersed or dissolved in some high molecular weight polyol) as a separate component.

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

[Example] A mixture of a high molecular weight polyol, a crosslinking agent, a blowing agent, etc. listed in Table 1 below was charged into a tank on the polyol component side of a high-pressure foaming machine, and a polyisocyanate was charged into a tank on the isocyanate component side. The discharge pressure of the high pressure foaming machine is 18
Reaction injection molding was carried out at a discharge rate of 200 g/sec and a liquid temperature of both components of 23±3°C.

800mm x 400mm x 10m as mold
A mold with internal dimensions of m(t) is used, and the mold temperature is set to 45
The temperature was adjusted to ~50'C. The time required for demolding (demolding time) was measured based on the appearance (and changes in the appearance) when the molded product was taken out after molding. In addition, the molded product was left overnight in an atmosphere controlled at 23° C., and its physical properties such as density, tensile strength, and elongation were measured. The results are shown in Table 1. Note that the amounts of raw materials used are expressed in parts by weight, excluding polyisocyanate.

The types of raw materials used in the present examples and comparative examples are as follows.

Polyol A: Polyoxybrobyleneoxyethylene triol having a hydroxyl value of 34 and a hydroxyl group number of 3, having 15% by weight of oxyethylene groups at the terminals.

Polyol B: Polymer-dispersed polyol containing 30% by weight of acrylonitrile-styrene copolymer fine particles using polyol A as a dispersion medium.

EG. Ethylene glycol (crosslinking agent) catalyst: Triethylenediamine-EG solution (trade name "Dabco-"
EG''') Foam stabilizer: Silicone foam stabilizer (trade name "SF-2962" manufactured by Toray Silicone Co., Ltd.) Polyisocyanate: Modified diphenylmethane diisocyanate (trade name "C-1050" manufactured by Nippon Polyurethane Co., Ltd.) ) Isocyanate content: 23% by weight The amount of polyisocyanate used is an index (100 times the equivalent of polyisocyanate per equivalent of all raw materials that react with isocyanate groups) Foam-breaking agent A: perfluoroalkyl group (Rf') A mixture of phosphoric acid monoesters and diesters of Rf'-CH.CH2-OH having 9 carbon atoms (the average number of Rf'CH2CHiO groups per molecule is 1.7) and diethanolamine to break the foam. Agent B: Silicone-based foam-breaking agent (product name “SRX-254” manufactured by Toray Silicone Co., Ltd.) Foaming agent: Trichlorofluoromethane Colorant: Carbon paste (Note) If the mold is removed 5 minutes after injection, the molded product will be damaged. Blisters and voids occurred.

[Effect of the invention] As is clear from the comparison between Examples and Comparative Examples, when conventional foam-breaking agents are used, it takes at least 5 minutes to demold after injection of raw materials.
If the demolding time is shorter than that, the molded product will be deformed, whereas when the foam-breaking agent of the present invention is used, a good molded product can be obtained with a demolding time of less than 5 minutes. Therefore, the foam-breaking agent of the present invention has an excellent effect as a foam-breaking agent for polyurethane foam, and especially when applied to the production of integral foam, its effect enables demolding in a shorter time and reduces the molding cycle. Effective for shortening.

Claims (1)

[Scope of Claims] 1. A foam-breaking agent for producing polyurethane foam comprising an acidic compound having a fluoroalkyl group or a salt thereof. 2. The foam-breaking agent according to claim 1, wherein the fluoroalkyl group is a highly fluorinated polyfluoroalkyl group having 3 to 17 carbon atoms and containing a polyfluoroalkyl group. 3. The foam-breaking agent according to claim 1, wherein the acidic compound is a phosphoric monoester, a phosphoric diester, or a mixture thereof of an alcohol containing a fluoroalkyl group. 4. The foam-breaking agent according to claim 1, wherein the salt is an amine salt. 5. The foam-breaking agent according to claim 1, which is a foam-breaking agent for producing polyurethane foam with integral skin. 6. Integral, which is characterized by reacting a high molecular weight polyol, a crosslinking agent, and a polyisocyanate in a mold in the presence of a catalyst, a blowing agent, a foam stabilizer, and an acidic compound having a fluoroalkyl group or a salt thereof. Method for manufacturing polyurethane foam molded products with skin. 7. The method according to claim 6, wherein the high molecular weight polyol is a polyoxyalkylene polyol having a hydroxyl value of 80 or less. 8. The method according to claim 6, wherein the high molecular weight polyol is a polymer-dispersed polyol containing fine polymer particles.