JP2000178374A - Method for producing polyurethane foam and polishing sheet - Google Patents

Abstract

[PROBLEMS] To provide a method for producing a microcellular polyurethane foam having uniform microcells without using a heterogeneous substance such as a foaming agent or a micro hollow foam. The present invention relates to a method for producing a microcellular polyurethane foam by mixing a first component containing an isocyanate group-containing compound and a second component containing an active hydrogen group-containing compound. A silicon-based nonionic surfactant is added to at least one of the two components, the surfactant-added component is stirred with a non-reactive gas, and the non-reactive gas is dispersed as fine bubbles to form a foam dispersion, The remaining components are mixed with the foam dispersion and cured, or a surfactant is added to at least one of the first component and the second component, and the first component and the second component are mixed with a non-reactive gas. After mixing and stirring, the non-reactive gas is dispersed as fine bubbles to form a bubble dispersion, and the bubble dispersion is cured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing a polyurethane foam having uniform fine cells. The microcellular polyurethane foam of the present invention can be suitably used as a polishing material suitable for polishing resins, silicon for manufacturing glass, lenses, quartz, semiconductors, etc., electronic substrates, optical substrates, and the like. The present invention also relates to a polishing sheet suitable as a polishing material, which is obtained by appropriately cutting the polyurethane foam obtained by the above-mentioned production method.

[0002]

2. Description of the Related Art As a technique for producing a polyurethane foam, a low boiling organic solvent such as chlorofluorocarbon or methylene chloride is added and dispersed in a foam-forming raw material composition, and the polymer is foamed by vaporization by heat of polymerization. It is well known that water is added to and dispersed in a foam-forming raw material composition, and a polymer is foamed by carbon dioxide gas generated by a reaction between an isocyanate group and water. The foam obtained by these methods has an average bubble diameter (cell diameter) of 100 μm as a lower limit, and it is difficult to obtain a foam having finer and uniform cells.

The following method is known as a method for producing a polyurethane foam having fine cells. (1) After dispersing solvent-soluble fine particles in a polyurethane polymer and molding into a predetermined shape, the molded article is immersed in a solvent in which the fine particles dissolve but the polyurethane polymer does not dissolve, and the fine particles are dissolved and removed. A method of forming a resin, that is, a foam. (2) A method of dispersing a micro hollow foam in a raw material composition for forming a polyurethane resin.

[0004]

However, according to the method (1), a large amount of solvent is required, and it is necessary to treat a solvent containing a material for forming fine particles, which is expensive. Moreover, the obtained foam is only open cells, and cannot be used for applications requiring rigidity, and the applications are limited. In addition, an elution step and a step of drying the solvent are required, and there is also a problem that it takes a long time to produce a thick molded article.

[0005] On the other hand, in the method (2), it is difficult to produce a uniform foam because the minute hollow foam tends to float in the polyurethane reaction stock solution due to the difference in density. Is relatively expensive,
Further, there is a problem that the material of the minute hollow foam remains in the foam and the blade is damaged when the foam is cut. Moreover, the hollow fine particles are liable to be scattered, requiring a great deal of cost for equipment for maintaining the working environment.

It is an object of the present invention to provide uniform fine bubbles without using a foreign substance such as a chemically reactive blowing agent such as water, a vapor-expandable blowing agent such as chlorofluorocarbon, a fine hollow foam, and a solvent-soluble substance. An object of the present invention is to provide a method for producing a polyurethane foam.

[0007]

The inventor of the present invention has prepared a first component containing an isocyanate group-containing compound (polyisocyanate compound), which is a raw material liquid for producing polyurethane, and a first component containing an active hydrogen group-containing compound (so-called polyol compound). By adding a surfactant to one of the two components and agitating it vigorously in the presence of a non-reactive gas, these liquids become a bubble dispersion containing fine non-reactive gas bubbles, The mixture is added, mixed and allowed to undergo a polymerization reaction to obtain a polyurethane foam having a uniform fine cell structure.Furthermore, a surfactant is included in the reaction solution, and a non-reactive gas is also present. By vigorously stirring underneath, these liquids become bubble dispersions containing fine non-reactive gas bubbles, polymerize and cure as they are, and form a polymer with a uniform fine bubble structure. It found that Tan foam is obtained, and have completed the present invention.

[0008] The invention described in claim 1 of the present application is a method for producing a microcellular polyurethane foam by mixing a first component containing an isocyanate group-containing compound and a second component containing an active hydrogen group-containing compound, A silicon-based nonionic surfactant is added to at least one of the first component and the second component, and the component added with the surfactant is stirred with a non-reactive gas to disperse the non-reactive gas as fine bubbles. The present invention relates to a method for producing a microcellular polyurethane foam, which comprises forming a cell dispersion, mixing the remaining components into the cell dispersion, and curing the mixture.

The invention according to claim 2 of the present application is a method for producing a microcellular polyurethane foam by mixing a first component containing an isocyanate group-containing compound and a second component containing an active hydrogen group-containing compound. Adding a silicon-based nonionic surfactant to at least one of the first component and the second component, mixing and stirring the first component and the second component together with a non-reactive gas, and finely dividing the non-reactive gas. The present invention also relates to a method for producing a microcellular polyurethane foam, which comprises dispersing cells as bubbles to form a cell dispersion, and curing the cell dispersion.

[0010] Here, the "non-reactive gas" refers to a gas composed only of a normal-temperature gas component that does not react with an isocyanate group or an active hydrogen group. Further, the gas may be positively sent into the liquid, or the gas may be naturally entrained during the stirring. Further, the term “fine bubbles” means that the diameter of the bubbles is 100 μm or less on average, more preferably 8 μm or less.
0 μm or less, and 10 μm on average according to the method of the present invention.
It can be manufactured to a degree. The diameter of the bubbles can be set and controlled by appropriately selecting and adjusting conditions such as the type and amount of surfactant used, the amount of stirring, and the viscosity of the raw material used. The density of the foam obtained is about 0.6 to 0.9, and the hardness of the foam (ASKER
C) is preferably from 85 to 100. In particular, the polishing foam preferably has a hardness of 90 to 95.

[0011] The stirring time varies depending on the performance of the stirrer, the viscosity of the reaction solution for forming the polyurethane foam, and the like.
It is more preferably at least about 1 minute to produce a stable foam dispersion liquid for at least 30 seconds, and stirring is possible as long as fluidity is ensured. This stirring time needs to be longer than the stirring time for producing a normal polyurethane foam. The diameter of the bubbles can be adjusted by the production conditions such as the type of surfactant to be added, the amount added, and the stirring time.

[0012] In any of the above-described methods for producing a microcellular polyurethane foam of the present invention, it is preferable that the method further includes a step of passing the cell dispersion through a sieve net. According to the first aspect of the present invention, one component, which is a cell dispersion, may be passed through a sieve screen, or may be passed after mixing the other components. According to the second aspect of the present invention, regardless of the order of mixing the first component, the second component, and the non-reactive gas, the bubble dispersion liquid is formed in a state where the first component and the second component are mixed. I just need.

By passing through a sieve screen, large gas bubbles generated during stirring are ruptured and disappear, and it is possible to obtain a fine cell polyurethane foam having higher cell uniformity.

In the present invention, the first component is an isocyanate prepolymer, and when the surfactant is added to the isocyanate prepolymer, it has excellent physical properties and has fine and uniform cells (cells). It is particularly preferred because a polyurethane foam is obtained.

The surfactant used in the present invention is a silicon-based nonionic surfactant having no hydroxyl group. By using such a surfactant, the physical properties of the polyurethane are not impaired and bubbles are generated. A fine and uniform polyurethane foam is stably obtained.

The surfactant is added in an amount of 5 to 50% by weight based on the total amount of the raw material components, ie, the first and second components.
It is preferred that If it is less than 5% by weight, a foam having fine cells may not be obtained, and if it exceeds 50% by weight, the physical properties of the polyurethane foam may be deteriorated.

A surfactant is added to an isocyanate prepolymer containing an isocyanate group, an active hydrogen-containing compound is added as a curing agent, mixed with a non-reactive gas and stirred, and the non-reactive gas is dispersed as fine bubbles. In the method in which the isocyanate prepolymer is cured by forming the foamed dispersion into an isocyanate group, the isocyanate group of the isocyanate prepolymer preferably contains an isocyanate group derived from an aliphatic isocyanate compound.

The isocyanate group derived from the aliphatic isocyanate compound has a lower reactivity than the isocyanate group derived from the aromatic isocyanate compound. It takes a long time to stop. For this reason, the dispersion time, the time for molding by pouring into a predetermined mold,
There is an effect that the time required for the step of passing the bubble dispersion liquid through the sieve screen can be secured. In the isocyanate prepolymer, an isocyanate group derived from an aromatic polyisocyanate compound may coexist.

The aliphatic isocyanate compound is
It is sufficient that the isocyanate group is not directly bonded to the aromatic ring, and it does not matter whether the isocyanate compound has an aromatic ring.

The present invention also relates to a polishing sheet using the polyurethane foam obtained by the above-mentioned production method, wherein abrasive dust or an abrasive is applied to the surface of the sheet outward from the contact surface between the object to be polished and the polishing sheet. It is characterized in that a groove having a releasing action is provided. The sheet may be manufactured by pouring the reaction components into a mold having the same cavity as the thickness of the sheet intended for the polyurethane foam,
Alternatively, a thick block-shaped foam may be manufactured and cut into a predetermined thickness.

The shape of the groove is not particularly limited, but the cross section may be rectangular, triangular, U-shaped, semi-circular or the like, and may have a cross-sectional area through which fine powder passes. The grooves are arranged on the sheet surface in a concentric shape, a lattice shape, or the like.

[0022]

DETAILED DESCRIPTION OF THE INVENTION As the isocyanate group-containing compound used in the present invention, a polyisocyanate compound known in the field of polyurethane can be used without any limitation. In particular, the use of a diisocyanate compound and its derivative, particularly an isocyanate prepolymer, is preferable because the resulting microcellular polyurethane foam has excellent physical properties. Incidentally, as a method for producing a polyurethane resin, a prepolymer method and a one-shot method are known, but any method can be used in the present invention.

Specific examples of the organic diisocyanate usable in the present invention include the following compounds.

Aromatic diisocyanate compound: 4,4'-diphenylmethane diisocyanate, 2,
4′-diphenylmethane diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, naphthalene diisocyanate, 1,4-phenylene diisocyanate, etc. Aliphatic diisocyanate compound ・ Ethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 1 Aliphatic diisocyanates such as 2,6-hexamethylene diisocyanate (HDI); hydrogenated 4,4'-diphenylmethane diisocyanate (HMDI, trade name Hylen-W, manufactured by Huls),
1,4-cyclohexane diisocyanate (CHD
I), isophorone diisocyanate (IPDI), hydrogenated m-xylylene diisocyanate (HXDI),
Alicyclic diisocyanates such as norbornane diisocyanate • Xylylene diisocyanate (XDI), tetramethyl xylylene diisocyanate (TMXDI), etc. The above compounds may be used alone or in combination.

In addition to the above diisocyanate compounds,
A trifunctional or higher polyfunctional polyisocyanate compound can also be used. As polyfunctional isocyanate compounds,
A series of diisocyanate adduct compounds are commercially available as Desmodur-N (Bayer) and trade name duranate (Asahi Kasei Kogyo). Since these trifunctional or higher polyisocyanate compounds are apt to gel during the synthesis of a prepolymer when used alone, it is preferable to use them in addition to a diisocyanate compound.

In the present invention, use as the first component is preferred.
The isocyanate group-containing compound is
Is a reaction product between a compound and an active hydrogen group-containing compound.
It is a cyanate prepolymer. Such active hydrogen groups
As the containing compound, the polyol compound described below is used
Isocyanate group (NCO) and active hydrogen group (H
^* ) Equivalent ratio NCO / H^* Is 1.6 to 2.6, preferably
Is an NC produced by a heat reaction in the range of 1.8 to 2.2.
Isocyanate prepolymers that are O-terminal oligomers
Is manufactured. Commercially available isocyanate prepolymer
The use of is also preferred.

The isocyanate group in the invention according to claim 6 can be obtained by using the above-mentioned aliphatic isocyanate compound as at least one component of the prepolymer-forming component. If the terminal unreacted NCO group is derived from an aliphatic isocyanate compound, an aromatic diisocyanate may be used as a prepolymer synthesis component.

The active hydrogen group-containing compound used in the present invention is an organic compound having at least two or more active hydrogen atoms, and is a compound usually called a polyol compound or a chain extender in the field of polyurethane.

The active hydrogen group is a functional group containing hydrogen which reacts with an isocyanate group, and examples thereof include a hydroxyl group, a primary or secondary amino group, and a thiol group (SH).

The polyol compound is an oligomer having a molecular weight of about 500 to 10,000 based on a terminal group determination method,
Specifically, the following are exemplified.

1) Polyether polyol As the polyether polyol, propylene oxide is added to one or more polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, glycerin, and trimethylolpropane. Polyoxypropylene polyols obtained, polyoxyethylene polyols obtained by adding ethylene oxide, butylene oxide, polyols obtained by adding styrene oxide, and the like, and ring-opening polymerization of tetrahydrofuran to the polyhydric alcohol Examples thereof include polyoxytetramethylene polyols obtained by addition. Copolymers using two or more of the above-mentioned cyclic ethers can also be used.

2) Polyester polyol As the polyester polyol, one of ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, cyclohexanedimethanol, glycerin, trimethylolpropane, pentaerythritol and other low molecular weight polyhydric alcohols is used. Or one or more of glutaric acid, adipic acid, pimelic acid, suberic acid, sebacic acid, terephthalic acid, isophthalic acid, dimer acid, hydrogenated dimer acid or other low molecular dicarboxylic acids or oligomeric acids and two or more types Condensation polymer with, propiolactone, caprolactone,
Examples thereof include polyols such as ring-opening polymers of cyclic esters such as valerolactone.

3) Acrylic polyol In an acrylic copolymer, β-hydroxyethyl acrylate, β-hydroxypropyl acrylate, 3-hydroxypropyl acrylate, β-hydroxybutyl acrylate, 4-hydroxybutyl acrylate, acrylic acid hydroxyalkyl esters of acrylic acid such as β-hydroxypentyl or similar hydroxyalkyl esters of methacrylic acid; further, glycerin, acrylate monoesters of polyhydric alcohols such as trimethylolpropane or methacrylic monoesters similar thereto, Monoethylenically unsaturated monomers having a hydroxyl group such as methylol acrylamide or N-methylol methacrylamide can be used as acrylic monomers having two or more hydroxyl groups in one molecule such as a copolymerized monomer.

As the acrylic polyol, a telechelic acrylic polyol can also be used. Such a telechelic acrylic polyol is obtained by polymerizing an unsaturated monomer containing a (meth) acrylic ester with an organic peroxide-containing initiator in the presence of an alcohol compound in the presence of an organic sulfonic acid compound. It is a hydroxyl group-containing acrylic polymer. As the alcohol compound, aliphatic or alicyclic alcohols such as methanol and ethanol are preferable. When a monofunctional alcohol is used as the alcohol compound, the active hydrogen group-containing acrylic polymer obtained is substantially bifunctional, and the alcohol compound When a diol is used, the active hydrogen group-containing acrylic polymer becomes substantially tetrafunctional.

4) Other polyols In addition, phenolic resin polyols, epoxy polyols, polybutadiene polyols, polyisoprene polyols, polyester-polyether polyols, polymer polyols obtained by adding or dispersing polymers such as acrylonitrile and styrene, and urea-dispersed polyols , Carbonate polyols and the like can be used as the polyol of the present invention. Further, a polyol compound obtained by condensing these polyol compounds with p-aminobenzoic acid and having an active hydrogen group as an aromatic amino group can also be used.

Among the active hydrogen group-containing compounds, those referred to as chain extenders are compounds having a molecular weight of about 500 or less. Specifically, aliphatic low molecular weight glycols represented by ethylene glycol, propylene glycol, 1,4-butanediol, trimethylolpropane and the like, triols, methylenebis-o-chloroaniline (MOC
A), aromatic diamines such as dicyclohexylmethane-4,4′-diamine, 1,4-bishydroxyethoxybenzene (Cuamine H (manufactured by Ihara Chemical Co.)), m
-Aromatic diols such as xylylene diol (manufactured by Mitsubishi Gas Chemical Company) can be used.

The non-reactive gas used to form the fine bubbles is preferably a non-flammable gas. Specifically, nitrogen, oxygen, carbon dioxide, a rare gas such as helium or argon, or a mixed gas thereof. The use of air that has been dried to remove water is most preferable in terms of cost.

As the silicon-based nonionic surfactant used in the present invention, when the above-mentioned first component, second component or a mixture thereof is stirred in the presence of a non-reactive gas, fine bubbles are stabilized. Those which are formed in an intended manner can be used without limitation.

In particular, surfactants used as foam stabilizers in the technical field of polyurethanes because of their good compatibility with polyol compounds and isocyanate prepolymers, such as hydroxyl groups which react with isocyanate groups as described above. Those having no active hydrogen group are used. Specifically, silicone foam stabilizers SH-190 and SH-192 (manufactured by Toray Dow Corning Silicon Co., Ltd.), L-5340
(Nihon Unicar Co., Ltd.) and the like.

In the present invention, a known stirring device can be used without particular limitation as the stirring device for dispersing the non-reactive gas in the form of fine bubbles into the first component, the second component, or a mixture thereof. Specifically, a homogenizer, a dissolver, a twin-screw planetary mixer (planetary mixer) and the like are exemplified. However, a stirrer that causes a strong temperature rise by stirring, particularly in the method of mixing the first component and the second component to form bubbles, as in the invention of claim 2, because the reaction speed increases, Not preferred. Although the shape of the stirring blade of the stirring device is not particularly limited,
Use of a whipper-type stirring blade is preferable because fine bubbles can be obtained.

In the first aspect of the present invention,
Stirring to form the foam dispersion and stirring to add and mix the remaining components are performed, but the latter-stage stirring need not be particularly stirring to form bubbles, and use of a stirrer that does not involve large bubbles is required. preferable. As such a stirring device,
Planetary mixers are preferred. In addition, there is no problem even if the same agitator is used for the former stage and the latter stage, and it is also preferable to use after adjusting the stirring conditions such as adjusting the rotation speed of the stirring blade as needed. .

The conditions for producing the cell dispersion liquid are not particularly limited as long as fine cells are formed and a cured product having a predetermined shape is obtained, but the temperature is not lower than the melting points of the first component and the second component. It is necessary that the temperature be lower than the temperature at which the curing reaction between the isocyanate group and the active hydrogen group does not proceed rapidly. Preferably 0 ° C to 140 ° C, more preferably 10 ° C
~ 120 ° C. The curing reaction between the isocyanate group and the active hydrogen group is an exothermic reaction, and the degree of heat generation differs depending on the type and combination of the selected isocyanate compound and active hydrogen compound. If the temperature rise of the system due to the heat of reaction is large, it is not preferable because the bubbles in the bubble dispersion expand.
When a reaction system with a small heat of reaction is employed, or when a reaction system with a large heat of reaction is used, it is preferable to perform sufficient temperature control.

In the method for producing a polyurethane foam of the present invention, heating and post-curing the foam that has reacted until the foam dispersion has flowed into the mold until the foam no longer flows improves the physical properties of the foam. It is effective and very suitable. The conditions in which the foam dispersion is poured into a mold and immediately placed in a heating oven to perform post-curing may be employed. Even under such conditions, heat is not immediately transmitted to the reaction components, so that the bubble diameter does not increase. The curing reaction is preferably performed at normal pressure because the bubble shape is stabilized.

In the present invention, a catalyst for accelerating the polyurethane reaction may be used. However, when the isocyanate compound and the active hydrogen group-containing compound are mixed and stirred, as in the invention of claim 2, a sufficient stirring time for forming fine bubbles and a flow time for pouring into a mold having a predetermined shape are ensured. It is necessary to select the type and amount of the catalyst taking these factors into consideration.

The production of the microcellular polyurethane foam of the present invention can be carried out by a batch system in which each component is weighed and charged into a container and stirred, or each component and a non-reactive gas are continuously supplied to a stirrer. A continuous production system may be used in which the mixture is supplied, stirred, and the foam dispersion is sent out to produce a molded product.

The sieve mesh used in the present invention only needs to remove relatively large air bubbles in the cell dispersion liquid. To obtain a foam having a cell diameter of 50 μm or less, a screen finer than 80 mesh should be used. I just need. In the case of a continuous production method, it is preferable to provide the manufacturing apparatus in the form of a strainer.

In the present invention, other components may be added in addition to the polyurethane-forming raw materials. Specific examples include fillers such as resin fine powder and inorganic fine powder, catalysts or retarders for adjusting the curing reaction rate, and coloring agents such as pigments and pigments.

[0048]

Embodiments of the present invention will be described below. (Example 1) Adiprene L-325 (isocyanate-terminated prepolymer, NCO
= 9.25% Uniroyal) (1st component) 100
20 g of a silicone foam stabilizer SH-192 (manufactured by Toray Dow Corning Silicon Co., Ltd.) as a surfactant was added to the resulting mixture, and a whipping mixer (rotating speed of stirring blades = 3500 rpm)
The mixture was stirred for about 5 minutes until the mixture became creamy (meringue state) to obtain a foam dispersion liquid 1. This bubble dispersion liquid 1 was transferred to a planetary mixer, and 26.6 g of Cuamine MT (methylene bis-o-chloroaniline, manufactured by Ihara Chemical Co., Ltd.) (second component) melted and kept at 120 ° C. was added thereto, and about 2 Mix for minutes. The mixture is poured into an open mold within a usable life having fluidity and cured, and the temperature is 110 ° C. ± 10 ° C.
Was post-cured for 6 hours in a temperature-controlled oven to produce a microcellular polyurethane foam. The surfactant used was 1 to the total amount of the first component and the second component.
It was 5.8% by weight.

The obtained fine cell polyurethane foam is
It had uniform air bubbles having a density of 0.75 g / cm ³ , a hardness (ASKER C) of 94, and an average cell diameter of 50 μm.

(Example 2) Adiprene L-325 (isocyanate-terminated prepolymer, NCO = 9.25%, manufactured by Uniroyal Co.) which was melted and temperature-controlled to 80 ° C (No. 1)
Ingredient) 100 g of silicone foam stabilizer SH as surfactant
To a premix to which 20 g of -192 (manufactured by Toray Dow Corning Silicone Co., Ltd.) was added, cure amine MT (methylene bis-o-chloroaniline, manufactured by Ihara Chemical Co., Ltd.) (second component) melted and kept at 120 ° C. 26.6
g until creamy (meringue state)
After stirring for 2 minutes, a bubble dispersion liquid 2 was obtained. This bubble dispersion liquid 2 is poured into an open mold within a usable life having fluidity,
The composition was cured in an oven controlled at 110 ° C. ± 10 ° C. and post-cured for 6 hours to produce a fine-cell polyurethane foam. The surfactant used was the first
It was 15.8% by weight based on the total amount of the component and the second component.

The obtained microcellular polyurethane foam is
It had uniform air bubbles having a density of 0.75 g / cm ³ , a hardness (ASKER C) of 94, and an average cell diameter of 30 μm.

Example 3 The amount of the surfactant added was 50 g.
(39.5% by weight based on the total amount of the first and second components) A microcellular polyurethane foam was prepared in the same manner as in Example 2. The obtained microcellular polyurethane foam has a density of 0.75 g / cm ³ and a hardness (ASK).
ERC) was 94, and the cells had uniform cells with an average cell diameter of 30 μm.

Comparative Example 1 A polyurethane foam was prepared in the same manner as in Example 2 without adding a surfactant. The obtained polyurethane foam had a large average cell diameter visually, was non-uniform, and was out of the question.

(Comparative Example 2) The amount of the surfactant added was 5 g.
(4.0% by weight based on the total amount of the first and second components)
A microcellular polyurethane foam was prepared in the same manner as in Example 2, except that The resulting polyurethane foam is
The average cell diameter was 100 μm, and it could not be said to be fine bubbles.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) // (C08G 18/00 101: 00) (72) Inventor Toshio Imai 1-17 Edobori, Nishi-ku, Osaka-shi, Osaka No. 18 Toyo Tire & Rubber Co., Ltd. F-term (reference) 3C063 AA06 AB07 BA02 BA24 BE01 BE06 BE12 4F071 AA53 AA82 AB17 AB32 AC12 AC13 AC16 AE01 AE02 AE03 AE10 AE13 AG28 DA08 DA20 4F074 AA78 AD17 BA32 BA33 BC05 CC02 DA06 CK031 CK041 CK051 EX006 FD316 GT00 4J034 DA01 DA05 DB01 DB03 DF01 DF02 DF11 DF12 DF14 DF15 DF16 DF19 DF20 DF21 DF22 DG01 DG03 DG04 DG05 DG06 DG09 HC12 HC12 HC01 HC12 HC01 HC02 HC52 HC54 HC61 HC64 HC66 HC67 HC71 HC73 LA24 MA17 NA08 NA09 PA02 QC01 RA19

Claims (7)

[Claims] 1. A method for producing a microcellular polyurethane foam by mixing a first component containing an isocyanate group-containing compound and a second component containing an active hydrogen group-containing compound, wherein the first component or the second component is mixed. A silicon-based nonionic surfactant having no hydroxyl group is added to at least one of the components, and the component to which the surfactant is added is stirred with a non-reactive gas to disperse the non-reactive gas as fine bubbles to disperse bubbles. A method for producing a microcellular polyurethane foam, comprising: forming a liquid; mixing the remaining components with the cell dispersion; and curing the mixture. 2. A method for producing a microcellular polyurethane foam by mixing a first component containing an isocyanate group-containing compound and a second component containing an active hydrogen group-containing compound, wherein the first component or the second component is mixed. A silicon-based nonionic surfactant having no hydroxyl group is added to at least one of the components, the first component and the second component are mixed and stirred with a non-reactive gas, and the non-reactive gas is dispersed as fine bubbles. A method for producing a microcellular polyurethane foam, which comprises forming a cell dispersion and curing the cell dispersion. 3. The method for producing a microcellular polyurethane foam according to claim 1, further comprising a step of passing the cell dispersion through a sieve screen. 4. The method according to claim 1, wherein said first component is an isocyanate prepolymer, and said surfactant is added to said isocyanate prepolymer. 5. The addition amount of the surfactant is 5 to 50% by weight based on the total amount of the first and second components.
5. The method for producing a microcellular polyurethane foam according to any one of items 4 to 4. 6. The method for producing a microcellular polyurethane foam according to claim 4, wherein the isocyanate group of the isocyanate prepolymer contains an isocyanate group derived from an aliphatic isocyanate compound. 7. A polishing sheet provided with grooves on the surface of a polyurethane foam sheet obtained by the production method according to claim 1.