JPH04359917A - Production of flexible polyurethane foam - Google Patents

Abstract

PURPOSE:To produce the title foam having good properties and low density or low hardness at a low mold temperature without using any fluorocarbon blowing agent. CONSTITUTION:A polyether polyol mixture prepared by mixing a polyether polyol of a hydroxyl value of 56.0mgKOH/g with a polyether polyol of a hydroxyl value of 100.0mgKOH/g and carbon black, water, a catalyst and a foam stabilizer are mixed with tolylene diisocyanate, and the resulting mixture is cured in a mold to obtain a flexible molded foam.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing flexible polyurethane foam using mold foaming. More specifically, the present invention relates to a method for producing a flexible polyurethane foam that has excellent moldability in a high-temperature mold when injecting a polyurethane stock solution in mold foaming by using a mixture containing a specific polyol.

0002

[Prior Art] Normally, when producing soft hot mold foam, a polyurethane stock solution is injected into a mold that has been adjusted to a temperature of 35 to 45 degrees Celsius, foaming is performed, and the mold is removed after a hardening reaction takes place in a high-temperature furnace. And you are getting the product.

[0003] The reason why the mold temperature must be adjusted to 35 to 45°C when pouring the polyurethane stock solution is that, for example, if the temperature is below 35°C, curing may be insufficient or density may increase, and if it is above 45°C, This is because the foam surface may peel off or cracks may occur inside the foam, making it impossible to obtain a good product.

In addition, trichlorofluoromethane (Freon-11) is normally used when producing low-density or low-hardness foams, but due to fluorocarbon regulations, the amount of fluorocarbons used must be reduced or It is desirable not to do so.

[0005]

[Problem to be Solved by the Invention] Therefore, if a good foam can be stably obtained even if the mold temperature at the time of injection of the polyurethane stock solution is 45°C or higher, it is possible to The cooling process can be significantly omitted and energy loss can also be prevented.

Furthermore, the foam obtained by increasing the mold temperature has a lower density due to the higher foaming efficiency. Therefore, the blowing agent must be reduced to obtain the same density as the foam at normal mold temperatures. In other words,
This means that the amount of fluorocarbons used can be reduced in response to the issue of fluorocarbon regulations, which will become important in the future.

[0007]

[Means for Solving the Problems] The present inventors have developed a flexible polyurethane foam that can obtain a good foam body even when the mold temperature is 45°C or higher when pouring a polyurethane stock solution, and can reduce the amount of CFC added. As a result of intensive studies to achieve this goal, the present invention has been achieved.

That is, the present invention provides a polyhydroxy compound,
When producing flexible polyurethane foam from organic polyisocyanate, catalyst, foam stabilizer, and blowing agent, as a polyhydroxy compound, hydroxyl value 20 to 80 mgKOH is used.
/g of polyoxyalkylene polyol (A) and/or polyol (A) containing polymer fine particles, and 0.01 to 0.01 as solid content for polyol (A).
This is a method for producing flexible polyurethane foam, characterized in that a mixture consisting of 4.0% by weight of carbon black is used.

The present invention also provides polyhydroxy compounds,
When producing flexible polyurethane foam from organic polyisocyanate, catalyst, foam stabilizer, and blowing agent, as a polyhydroxy compound, hydroxyl value 20 to 80 mgKOH is used.
/g of polyoxyalkylene polyol (A) and/or polyol (A) containing polymer fine particles, a hydroxyl value of 85 to 1 equal to or less than the weight of polyol (A)
80mgKOH/g polyoxyalkylene polyol (B) and/or polyol containing polymer fine particles (B)
), and polyol (A) and polyol (B)
0.01 to 4.0% by weight as solid content based on the total of
This is a method for producing flexible polyurethane foam, characterized by using a mixture of carbon black.

In the present invention, the polyoxyalkylene polyol is a polyether polyol obtained by adding an alkylene oxide to a compound having at least two hydrogen atoms to which alkylene oxide can be added (hereinafter referred to as an initiator).

Although small amounts of other monoepoxides such as halogen-containing alkylene oxides, styrene oxides, glycidyl ethers, etc. may be added together with the alkylene oxide, preferably substantially only the alkylene oxide is used.

[0012] The alkylene oxide has 2 to 4 carbon atoms.
Alkylene oxides are suitable, and propylene oxide alone or a combination of propylene oxide and ethylene oxide is particularly preferred. When propylene oxide and ethylene oxide are used together, a mixture of both may be added, they may be added separately and sequentially, or they may be added in combination. The hydroxyl value of the polyoxyalkylene polyol is controlled by the amount of alkylene oxide added.

When ethylene oxide is added last, it is capped with ethylene oxide. Furthermore, the proportion of primary hydroxyl groups can be adjusted by further adding a small amount of propylene oxide after capping with ethylene oxide.

[0014] As the initiator, polyhydric alcohols, polyhydric phenols, mono- or polyamines, and others can be used, but polyhydric alcohols and polyhydric phenols are suitable, and polyhydric alcohols are particularly preferred. Moreover, two or more types of initiators can also be used in combination. Specific examples of initiators are shown below, but are not limited to these. A particularly preferred initiator is a trihydric polyhydric alcohol, or a mixture thereof with a dihydric, tetrahydric or higher hydric initiator.

Divalent initiator: ethylene glycol,
Diethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol, bisphenol A. Trivalent initiators: glycerin, trimethylolpropane, hexanetriol. Initiators with a valence of 4 or higher: pentaerythritol, diglycerin, ditrimethylolpropane, dextrose, sorbitol,
Sucrose, novolac.

Polyols containing fine polymer particles can be prepared by polymerizing ethylenically unsaturated monomers in polyols, by mixing separately produced polymer particles with polyols, by using macromonomers having ethylenically unsaturated groups and ethylenically unsaturated monomers. It is produced by polymerizing in polyol. This polyol containing fine polymer particles is also called a polymer polyol.

As the ethylenically unsaturated monomer, for example, styrene, acrylonitrile, etc. are used. For example, a polymer polyol obtained by graft-polymerizing these monomers in polyol (A) or polyol (B) in the presence of a free radical polymerization catalyst can be used as part or all of each of (A) and (B). The amount of the polymer fine particles is 50% by weight or less based on the total polyol, especially 3% by weight or less based on the total polyol.
It is preferably 0% by weight or less.

The other main raw material for the production of flexible polyurethane foams is polyisocyanate compounds. As the polyisocyanate compound, various compounds having two or more isocyanate groups can be used, but aromatic polyisocyanates are particularly suitable. Suitable aromatic polyisocyanates include mononuclear or polynuclear compounds having isocyanate groups bonded to aromatic nuclei, and modified products thereof.

Specific examples include tolylene diisocyanate, diphenylmethane diisocyanate, polymethylene polyphenylisocyanate, and prepolymer types, carbodiimide types, urea types, and other modified products thereof.

Two or more of these polyisocyanate compounds can also be used in combination. The amount of the polyisocyanate compound used is approximately 90 to 120, expressed as 100 times the number of isocyanate groups to the number of active hydrogens in the total active hydrogen-containing compound (usually referred to as isocyanate index).
In particular, about 95 to 110 is suitable. The active hydrogen-containing compound is mainly a polyol such as the above-mentioned polyoxyalkylene polyol, but it also contains a small amount of water as a blowing agent, and in some cases, if a chain extender or crosslinking agent is used, they may also be used. included.

Another essential component of the foamable mixture is the catalyst. As a catalyst for producing flexible polyurethane foam, a tertiary amine catalyst and an organometallic compound, particularly an organotin compound, are usually used, and they are usually used in combination. Various tertiary amine catalysts can be used as the tertiary amine catalyst.

For example, triethylenediamine, N-ethylmorpholine, N,N-dimethylaminoethylmorpholine, triethylamine, N,N,N',N'-tetramethylhexamethylenediamine, bis(2-dimethylaminoethyl)ether, N,N',N'-trimethylaminoethylethanolamine, and the like.

Two or more of these can be used in combination. A particularly preferred tertiary amine catalyst is triethylene diamine, and most suitable is a mixture of triethylene diamine and dipropylene glycol in a weight ratio of 1:2, which is well known under the trade name "DABCO 33LV."

The amount used can be varied depending on the desired reaction conditions, etc., but it is usually about 0.01 to 1.0 parts by weight, preferably 0.01 to 1.0 parts by weight, per 100 parts by weight of the polyol.
02 to 0.5 parts by weight is appropriate, especially "Dabco 33
It is appropriate to use 0.1 to 0.5 parts by weight of LV.

As the organometallic compound catalyst, organotin compound catalysts are most preferable, such as stannath octoate, stannath slaurate, dibutyltin dilaurate,
Examples include dibutyltin dimaleate, dibutyltin diacetate, and dioctyltin diacetate. In particular, stannath octoate and dibutyltin dilaurate are preferred.

The amount of the organotin compound catalyst used is usually 0.01 to 1.0 parts by weight per 100 parts by weight of the polyol. However, the amount of this catalyst used needs to be slightly changed depending on the type of polyol, reactivity, and other conditions, and the various optimal ranges are relatively narrow. This is explained in JP-A-54-1
This is the same as the description of the usable range of tin catalyst in the production of high elastic foam as described in Japanese Patent No. 54498 and the like.

Another ingredient added to the foamable mixture is a blowing agent. As the blowing agent, water or a halogenated hydrocarbon blowing agent is suitable, but a low boiling point gas such as air or another blowing agent may be used alone or in combination with water or a halogenated hydrocarbon blowing agent. Moreover, water and a halogenated hydrocarbon foaming agent can also be used together.

Examples of the halogenated hydrocarbon blowing agent include trichlorofluoromethane, dichlorodifluoromethane, methylene chloride, monochlorodifluoromethane, 1,1-dichloro-2,2,2-trifluoroethane, 1,1- Examples include dichloro-1-fluoroethane. A particularly preferred blowing agent is water, the amount of which can vary depending on the desired foam density, but usually polyol.
It is about 1 to 8 parts by weight, especially about 2 to 6 parts by weight per 100 parts by weight.

Another normally essential component is a siloxane foam stabilizer, such as polydialkylsiloxane, polydialkylsiloxane-polyoxyalkylene block copolymer, and the like. Other optional ingredients include, for example, colorants, antioxidants, ultraviolet absorbers, light stabilizers, flame retardants, and other additives that can be used in the production of cured foams.

[0030] The carbon black used in the present invention is a general-purpose carbon black that is generally widely used and is produced by an oil furnace method, etc., and has an average particle diameter of usually 5 to 200 (mμ) and a surface area of 10 to 10.
00 (m2/g). The particle size of carbon black used in the present invention is more preferably 10 to 30 (mμ).

It is essential that the amount of carbon black added to the polyoxyalkylene polyol is 0.01 to 4.0% by weight based on the polyoxyalkylene polyol. A more preferable blending amount is 0.05 to 2.0
% by weight, especially from 0.05 to 1.0% by weight. If the amount is less than this range, the high temperature molding properties of the flexible polyurethane foam will not reach the desired level. Even if the blending amount exceeds this range, the effect of improving moldability is small, and on the contrary, various problems tend to occur. For example, cell roughness occurs on the surface of the foam, and cracks tend to occur inside the foam.

Among the polyhydroxy compounds used in the present invention, the hydroxyl value of polyol (A) is 20 to 80 mg.
KOH/g. This hydroxyl value is 20mgKOH/
If it is less than g, the foam will collapse during foaming. In addition, if the hydroxyl value exceeds 80mgKOH/g,
The foam becomes closed cells with no air permeability, and in severe cases, shrinkage occurs. The hydroxyl value of the polyol (B) is 85 to 180 mgKOH/g.

In the present invention, the polyhydroxy compound used is polyol (A) alone or a mixture of polyol (A) and polyol (B). When polyol (A) and polyol (B) are mixed, polyol (B) is used in an amount equal to or less than that of polyol (A).

[0034]

[Examples] The present invention will be specifically explained below with reference to Examples and Comparative Examples. Hereinafter, parts refer to parts by weight.

[Examples 1 to 3] Hydroxyl value 56.0 m obtained by addition polymerizing alkylene oxide to glycerin
Hydroxyl value 100.0 mgKOH obtained by addition polymerizing alkylene oxide to gKOH/g polyether polyol (hereinafter referred to as (a)) and glycerin
/g of polyether polyol (hereinafter referred to as (b)) at a weight ratio of 70:30, and the solid content is 0.2% by weight based on the mixed polyether polyol. Carbon black (hereinafter referred to as C.B.) was blended so as to have the following properties.

450 parts of this mixture, 18 parts of water, 1.35 parts of DABCO 33LV (manufactured by Sun-Apro), 1.35 parts of N-methylmorpholine, 6.75 parts of SZ-1105 (silicone foam stabilizer manufactured by Nippon Unicar) was placed in a 2 liter polyethylene container, stirred at 3000 rpm for 30 seconds, the liquid temperature was adjusted to approximately 25°C, 0.45 part of Stanus octoate was added, stirred for an additional 5 seconds, and immediately
Add TDI-80 (NCO index 100), stir for 5 seconds, and make a 350 mm long, 350 mm wide,
60°C (Example 1) and 5°C, respectively, with a height of 100 mm.
The mixture was poured into an aluminum mold at 0°C (Example 2) or 40°C (Example 3), and the mold was placed in an oven set at 150°C and cured for 12 minutes to obtain a flexible molded foam. . The results are shown in Table 1.

[Example 4] Only polyether polyol (a) was used as the polyol, and C.I. B. A polyether polyol containing the following was produced. 450 parts of this mixture, 20 parts of water, 0.8 parts of DABCO 33LV, 0.4 parts of bis(2-dimethylaminoethyl) ether, and 8 parts of SF-2904 (silicone foam stabilizer manufactured by Toray Silicone) were added to 2 liters of polyethylene. After stirring at 3000 rpm for 30 seconds, the liquid temperature was adjusted to 25°C and 0.54 part of Stanus octoate was added. 60 in the same manner as in Example 1.
A soft molded foam was obtained by injecting it into a mold at ℃. The results are shown in Table 1.

[Comparative Example 1] Polyether polyol (a
): polyether polyol (b) at a weight ratio of 40:
The C.I. B.
The raw material mixture was poured into a mold at 60° C. in the same manner as in Example 1, except that a mixture containing the following was used to obtain a flexible molded foam. The results are shown in Table 2.

[Comparative Example 2] Only polyether polyol (a) was used as the polyol, and 450 parts of this polyether polyol (a), 15 parts of water, and DABCO 33
1.35 parts of LV, 1.35 parts of N-methylmorpholine, and 6.75 parts of SZ-1105 were placed in a 2 liter polyethylene container and stirred at 3000 rpm for 30 seconds, the liquid temperature was adjusted to 25°C, and Octoate 0
．． Added 36 parts. In the same manner as in Example 1, this raw material mixture was poured into a mold at 60°C to obtain a flexible molded foam. The results are shown in Table 2.

[0040]

[Table 1]

[0041]

[Table 2]

[0042]

Effects of the Invention The present invention has the effect that a good foam body can be produced smoothly and advantageously even when the mold temperature is high. Another effect is that a foam with low density or hardness can be produced without using or reducing the amount of fluorocarbon blowing agent used.

Claims (2)

[Claims] Claim 1: In producing flexible polyurethane foam from a polyhydroxy compound, an organic polyisocyanate, a catalyst, a foam stabilizer, and a blowing agent, the polyoxyalkylene polyol (A ) and/or polyol (A) containing polymer fine particles, and polyol (A) containing
) A method for producing a flexible polyurethane foam, characterized in that a mixture consisting of carbon black in a solid content of 0.01 to 4.0% by weight is used. [Claim 2] In producing flexible polyurethane foam from a polyhydroxy compound, an organic polyisocyanate, a catalyst, a foam stabilizer, and a blowing agent, a polyoxyalkylene polyol (A ) and/or polyol (A) containing polymer fine particles, a hydroxyl value of 85 to 180 mg KOH/less than the equivalent weight to polyol (A)
g polyoxyalkylene polyol (B) and/or
Alternatively, a mixture consisting of polyol (B) containing polymer fine particles and carbon black in a solid content of 0.01 to 4.0% by weight based on the total of polyol (A) and polyol (B) is used. A method for producing characteristically flexible polyurethane foam.