JPH0228612B2 - - Google Patents

Description

[Detailed description of the invention]

[Field of Application of the Invention] The present invention relates to a composition for producing a polyurethane foam, and more particularly to an internally added mold release agent when producing a hard skinned polyurethane foam. [Background of the Invention] Polyurethane foam can be obtained by injecting into a mold a reactive mixture consisting of a compound having at least two hydrogen atoms that reacts with polyisocyanate and additives such as a blowing agent, and then foaming and curing. . In order to prevent the foam from sticking to the surface of the mold when the foam is released from the mold, a mold release agent such as wax or silicone oil has conventionally been applied inside the mold cavity. However, this method has many problems when producing foam continuously. That is, the mold release agent must be applied every time one form is made, and the molding operation is interrupted during this time. Moreover, the applied mold release agent accumulates on the cavity surface as the number of molding cycles increases, adversely affecting the surface properties of the resulting foam. On the other hand, Japanese Patent Application Laid-Open No. 140996/1983 discloses that if certain additives are added to a composition for producing polyurethane, it becomes unnecessary to apply a mold release agent to the mold. This additive (internal mold release agent) is a polydimethylsiloxane having a hydroxyl group at the end. However, this internal mold release agent has poor compatibility with compounds having active hydrogen atoms in the molecule, and when attempts are made to continuously manufacture the foam, the polydimethylsiloxane separates and the composition becomes unstable. However, there is a problem that the mold releasability is not stable. [Object of the Invention] An object of the present invention is to provide a composition for producing a rigid polyurethane foam, which contains an internal mold release agent and is free from the above-mentioned problems. [Summary of the Invention] The present invention provides a composition for producing a rigid polyurethane foam containing a polyisocyanate compound, a compound having an active hydrogen atom in the molecule, a blowing agent, a catalyst, and an internal mold release agent as essential components. The agent has the following general formula n: An integer of 7 to 30 R ₁ , R ₂ : Hydrogen or aliphatic hydrocarbon containing 1 to 6 carbon atoms R ₃ : An amino group represented by an aliphatic hydrocarbon containing 2 to 4 carbon atoms It is characterized by using a salt of polydimethylsiloxane and fatty acid contained therein. The salt used as the internal mold release agent has good compatibility with compounds having active hydrogen in the molecule,
Demonstrates excellent mold release effect when removing the foam from the mold. The amino group-containing polysiloxane (hereinafter referred to as aminopolysiloxane) which is a raw material for the internal mold release agent used in the present invention is a linear siloxane having 7 to 30 dimethylsiloxane units. Theoretically, polysiloxanes containing more than 30 Si atoms can be used in some cases, but they are not preferred raw materials because of their poor compatibility with other components of the composition, especially compounds with active hydrogen atoms. .
In addition, those having less than 7 dimethylsiloxane units have good compatibility with other components, but have the problem of not exhibiting a sufficient mold release effect, and are therefore not preferred raw materials. The above aminopolysiloxane can be produced by reacting polysiloxane and amino alcohol. For example, there are 12 Si in one molecule.
α,ω-Dichloro-polydimethylsiloxane having atoms is kept at 80°C and added dropwise to a toluene solution of ethanolamine kept at 80°C, and stirred at 80°C for 3 hours. The chlorine is then removed in the form of NH ₄ cl by passing NH ₃ through this solution. Finally, the residues of toluene and NH ₃ are removed in vacuo to obtain the aminopolysiloxane. Aminopolysiloxanes having different chain lengths can also be produced in a similar manner. In this case, the alkanolamines include, in addition to ethanolamine, N-methylethanolamine, N,N-dimethylethanolamine, N-ethylmorpholine, N-cyclohexylethanolamine, N-ethylethanolamine, and N,N- Diethylethanolamine can also be used. The fatty acid serving as a raw material for the internal mold release agent used in the present invention preferably has 7 or more carbon atoms, and is particularly preferably a long-chain fatty acid with 12 to 20 carbon atoms. Natural or synthetic dicarboxylic and polycarboxylic acids can also be used, including azelaic acid,
natural or synthetic monocarboxylic acids or natural fatty acid mixtures such as palmitic acid, stearic acid, oleic acid, elaidic acid, linoleic acid, ricinoleic acid and fatty acid esters thereof, linoleic acid, such as soybean oil fatty acid, coconut oil fatty acid, peanut oil fatty acid, Commercial products such as tall oil fatty acids can be used. A fatty acid or a fatty acid mixture that is liquid at room temperature is desirable, and particularly oleic acid and/or a commercially available fatty acid mixture whose main components are oleic acid and soybean oil fatty acid or an esterified product of oleic acid and linoleic acid are preferred. Salts used as internal mold release agents can be easily made by stirring aminopolysiloxanes and fatty acids at room temperature. The blending ratio of aminopolysiloxane and fatty acid is preferably such that the amino group and the carboxyl group are present in equal moles, but the amino group is present per mole of the carboxyl group.
It is sufficient if it is 0.5 to 1.5 mol. The above-mentioned internal mold release agent can be used by being mixed in advance with a compound having an active hydrogen atom. The appropriate amount is 0.5 to 5 parts by weight per 100 parts by weight of the compound having an active hydrogen atom. The reason for this is that if it is less than 0.5 parts by weight, the mold release effect may be poor, and if it is more than 5 parts by weight, some of the active hydrogen atoms may separate or the mechanical properties of the obtained foam may deteriorate. There are cases where Examples of compounds having active hydrogen atoms in the molecule used in the present invention include polyether polyols, polyester polyols, polyester thioethers, and polycarboxylic acids. Among these, particularly important compounds are polyether polyols. Specific examples include polyhydric alcohols such as glycerin, trimethylolpropane, triethanolamine, pentaerythritol, diglycerin, bisphenol A, bisphenol F, sorbitol, and sucrose, and alkylene oxide (ethylene oxide,
Compounds with propylene oxide, butylene oxide), ammonia, monoethanolamine, diethanolamine, ethylenediamine,
There are compounds in which alkylene oxide is added to amine compounds such as 4,4'-diaminodiphenylmethane and tolylene diamine. Mixtures of these can be used if desired. Polyisocyanate compounds that can be used in the present invention include aliphatic polyisocyanates, ie chain polyisocyanates and cycloaliphatic polyisocyanates, and aromatic polyisocyanates. The most important of these is MDI, which is obtained by reacting the reaction product of aniline and formaldehyde with phosgene.
(4,4'-diphenylmethane diisocyanate)
It is a type compound. Here, not only MDI single items, but also
This also includes isocyanates similar to this, such as polyphenyl polymethyl isocyanate, carbodiimidized MDI, and compounds generally referred to as crude MDI. Furthermore, xylylene diisocyanate, isophorone diisocyanate, tolylene diisocyanate, and prepolymers having isocyanate terminals obtained from these compounds and the above-mentioned compounds having active hydrogen are also important compounds. Mixtures of these can be used if desired. The blending amount of polyisocyanate relative to the active hydrogen compound is 0.5 to 1.5, particularly 0.9 to 1.3 in terms of isocyanate index. In addition to water, blowing agents used in the present invention include low-boiling organic liquid compounds such as trichlorofluoromethane, methylene chloride, and n-heptane, and azobisisobutyronitrile, which generate nitrogen gas by decomposition. There are compounds that do this. Of these, water acts not only as a blowing agent but also as a crosslinking agent. Halogenated hydrocarbons with low boiling points (0 to 60°C), such as trichlorofluoromethane, have low thermal conductivity and form a foam with a high density outer shell, making them suitable as blowing agents for parts that require insulation performance. This is particularly important. The above-mentioned blowing agent is generally used by being mixed in advance with a compound having active hydrogen, but foams with different densities can be obtained by changing the amount of the blowing agent. Examples of the catalyst used in the present invention include various tertiary amines and compounds containing metals such as tin. Specific examples of tertiary amines include triethylenediamine, dimethylethanolamine, N-methylmorpholine, N-ethylmorpholine, N-cocomorpholine, N,N-dimethylcyclohexylamine, 1,2-dimethylimidazole, 1- Methylimidazole, 1,8-diazabicyclo[5,4,0]undecoo-7-ene,
There are aminoalkylsilanes and the like, and their brenceyutetate salts can also be used. Examples of tin-containing compounds include dialkyltin salts of carboxylic acids such as dibutyltin dilaurate, dibutyltin diacetate, dibutyltin maleate, and dioctyltin diacetate. In the present invention, a foam stabilizer can be added as necessary. Typical examples of these are oxyalkylene copolymers of polydimethylsiloxane and fluorine-based compounds. Other materials that can be used in the present invention include fillers, pigments, dyes, flame retardants, and ultraviolet absorbers. These materials are used by being mixed in advance in a compound having an active hydrogen atom or in a polyisocyanate compound. In order to produce polyurethane foam using the composition of the present invention, a solution A containing a compound having an active hydrogen atom as a main component and a solution B containing a polyisocyanate compound as a main component are mixed. The foam may be discharged into a mold and allowed to foam and harden over a predetermined period of time. However, the mold releasability of the foam, which is a feature of the present invention, is achieved by collision-mixing liquid A containing trichlorofluoromethane as a blowing agent and liquid B using MDI isocyanate using a high-pressure foaming machine. It is particularly good when injected inside. The reason for this is that during the foaming and curing process, the foaming agent aggregates on the mold surface to form a dense skin, and the internal mold release agent oozes out toward this skin. [Examples of the Invention] Hereinafter, examples of the present invention will be shown and explained in more detail, and comparative examples for demonstrating the effects thereof will also be described. First, the internal mold release agent of the present invention will be described. Internal mold release agent A: Salt of 1 mol of aminopolysiloxane shown below and 1 mol of oleic acid This polysiloxane has n=7, R ₁ =CH ₃ , R ₂ =H, and R ₃ =CH ₂ in the above general condition. Internal mold release agent B: Salt of 1 mol of aminopolysiloxane shown below and 1 mol of oleic acid In the above general formula, n=12 R ₁ =CH ₃ , R ₂ =H, and R ₃ =CH ₂ . Internal mold release agent C: Salt of 1 mol of aminopolysiloxane shown below and 1 mol of oleic acid This polysiloxane has the above general formula with n=30, R ₁ =CH ₃ , R ₂ =H, and R ₃ =CH ₂ . Internal mold release agent D: Salt of 1 mol of aminopolysiloxane shown below and 1 mol of oleic acid This polysiloxane has the general formula That is. Internal mold release agent E: Salt of 1 mol of aminopolysiloxane shown below and 1.5 mol of oleic acid In the above general formula Internal mold release agent F: Salt of 1 mol of aminopolysiloxane shown below and 1 mol of ricinoleic acid This polysiloxane has the general formula That is. For each example described below, the first
Polyurethane foam was manufactured using the equipment and molding conditions shown in the table. Example 1 Using the composition shown in the column of Example 1 in Table 2,
A hard polyurethane foam with a skin having a density of 0.5 g/cm ³ was manufactured using the equipment and molding conditions shown in Table 1. The surface of the mold was previously cleaned using gauze containing acetone. Molding was performed continuously 10 times without applying a mold release agent to the mold surface, and the mold releasability was good and the molded product could be easily removed from the mold. That is, as a compound with active hydrogen, 4,

【table】

【table】

〔Effect of the invention〕

As mentioned above, since a polyurethane foam with good mold releasability can be obtained by using the composition of the present invention, the work of applying a mold release agent to the mold surface, which was conventionally necessary, becomes unnecessary. Therefore, the molding cycle can be significantly shortened compared to the conventional method, and production efficiency can be dramatically improved.

Claims (1)

[Scope of Claims] 1. A composition for producing a rigid polyurethane foam containing a polyisocyanate compound, a compound having an active hydrogen atom in the molecule, a blowing agent, a catalyst, and an internal mold release agent as essential components, wherein the internal mold release agent is Shown by the general formula below n: An integer of 7 to 30 R ₁ , R ₂ : Hydrogen or aliphatic hydrocarbon containing 1 to 6 carbon atoms R ₃ : Aliphatic hydrocarbon containing 2 to 4 carbon atoms Polymer containing amino group A composition for producing a rigid polyurethane foam, characterized in that it uses a salt of dimethylsiloxane and a fatty acid. 2. The composition for manufacturing a rigid polyurethane foam according to claim 1, wherein the amount of the internal mold release agent is 0.5 to 5 parts by weight per 100 parts by weight of the compound having an active hydrogen atom. thing.