JPH0912655A - Production of water-base resin dispersion, and coating agent comprising same - Google Patents

Abstract

PURPOSE: To obtain a water-base resin dispersion which can form a coating film improved in clarity by subjecting a soln. of a free-radical-polymerizable silicone macromonomer in another vinyl monomer to free-radical copolymn. in a water-base dispersion in the presence of a specific high-molecular emulsifier. CONSTITUTION: A soln. in an amount of 100 pts.wt. prepd. by dissolving 1-50 pts.wt. silicone macromonomer having free-radical-polymerizable groups at the molecular ends and a number average mol.wt. by GPC of 1,000-100,000 (in terms of polystyrene) and obtd. by the condensation of a silanol-terminated silicone with an organosilicon compd. in 99-50 pts.wt. at least one vinyl monomer emulsifiable in a water-base medium is copolymerized in the presence of 0.1-5 pts.wt. free-radical polymn. initiator and 1-100 pts.wt. high-molecular emulsifier comprising a water-sol. graft copolymer which is obtd. by neutralizing, with a base, a part of or all the carboxyl groups of a graft copolymer obtd. by copolymerizing a macromonomer having (meth)acryloyl groups at the ends of a silicone molecule, an α,β-ethylenically unsatd. carboxylic acid, and other free-radical-polymerizable monomers.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is capable of producing an aqueous resin dispersion in which fine resin particles are suspended by subjecting a radical polymerizable silicone macromonomer and another radical polymerizable monomer to aqueous emulsion polymerization. The present invention relates to a production method for obtaining well and a coating agent comprising the above-mentioned aqueous resin dispersion.

[0002]

2. Description of the Related Art In recent years, structurally controlled graft polymers obtained by copolymerizing macromonomers, which are high molecular weight monomers having a polymerizable group at the end of the molecule, with other copolymerizable monomers have been proposed. , Is attracting attention as a high-performance polymer material, paint,
It is useful as an adhesive or a polymer additive.

Among the above graft polymers, a silicone-based polymer obtained by copolymerizing a radical-polymerizable macromonomer having a silicone skeleton such as polydimethylsiloxane (hereinafter referred to as "silicone-based macromonomer") with another monomer. The graft polymer has properties derived from a macromonomer as a branch component thereof, that is, water repellency, stain resistance, low abrasion resistance, and the like, and thus is suitably used as a coating agent or paint for various substrates (for example, JP-A-63-227670). Conventionally, such a silicone-based graft polymer was produced exclusively by solution polymerization, and a solvent type product was generally used as a product. However, this solvent type product can solve problems such as air pollution due to organic solvents and waste of resources. Therefore, recently, an aqueous emulsion is required.

Under such circumstances, many studies have been conducted on aqueous polymerization of silicone macromonomers and copolymerizable monomers. For example, in JP-A-5-9248, an aqueous dispersion in which a silicone macromonomer, a copolymerizable monomer and an oil-soluble polymerization initiator are emulsified and dispersed in water, that is, a so-called pre-emulsion is dropped into water at a predetermined temperature. It has been proposed that a specific surfactant such as sodium sulfosuccinate or the like be used as an emulsifier for forming the pre-emulsion.

According to the method described in the above publication, stable aqueous polymerization is possible, and an aqueous emulsion which is more or less uniform in appearance can be obtained, but the coating film formed from it has a problem of poor transparency. . According to the study by the present inventors, in order to solve the above-mentioned problem of transparency, it was necessary to use a special device to reduce the size of the pre-emulsion to about 0.5 μm or less.

[0006]

DISCLOSURE OF INVENTION Problems to be Solved by the Invention The inventors of the present invention have conducted multifaceted studies on a method of aqueous emulsion polymerization of a radical-polymerizable silicone macromonomer and another copolymerizable monomer, and as a result, silicone was used as an emulsifier. Was selected as a branch component, and a polymer containing a carboxylate group consisting of a vinyl polymerizable monomer was used as a backbone component to select a polymer emulsifier composed of a water-soluble graft copolymer, which was once refined. Pre-emulsion, that is, fine resin particles having an average particle diameter of 0.1 to 0.2 μm are homogeneously emulsified and dispersed without resorting to the complicated method of forming an aqueous emulsion dispersion of monomers and polymerizing the same. It was confirmed that an aqueous resin dispersion having the above properties was obtained.

The polymer emulsifier comprising the above water-soluble graft copolymer has already been proposed by the applicant of the present application as JP-A-5-154369, and specifically, (a) at the terminal of the silicone molecule (meta ) One of the carboxyl groups in the graft copolymer obtained by copolymerizing a macromonomer having an acryloyl group, (b) α, β-ethylenically unsaturated carboxylic acid, and (c) another radically polymerizable monomer It is obtained by neutralizing a part or the whole amount with a base. The polymeric emulsifier has excellent water resistance when used in the production of water-based resin emulsion type adhesives and coatings for monomers such as alkyl (meth) acrylate, styrene, vinyl acetate and (meth) acrylonitrile. However, it has not been disclosed to use it as an emulsifier when a silicone-based macromonomer is copolymerized with another vinyl monomer.

An object of the present invention is to provide a method for producing a silicone-based water-based resin dispersion which gives a coating film having excellent transparency without the complicated operation of refining the pre-emulsion using a special apparatus, and Another object of the present invention is to provide a coating agent comprising the aqueous resin dispersion obtained by the method.

[0009]

The method for producing an aqueous resin dispersion according to the present invention for achieving the above-mentioned object includes a method in which a silicone macromonomer having a radical-polymerizable group is copolymerizable with the macromonomer. (A) Macromonomer having a (meth) acryloyl group at the end of the silicone molecule, (b) α, β-ethylenically unsaturated carboxylic acid, and (c) other radical polymerization In the presence of a polymer emulsifier consisting of a water-soluble graft copolymer obtained by neutralizing a part or all of the carboxyl groups in the graft copolymer obtained by copolymerizing a water-soluble monomer with a base, in an aqueous medium. The constitution is characterized in that the silicone-based macromonomer is dispersed and copolymerized with another vinyl monomer by a radical polymerization initiator.

The coating agent according to the present invention is characterized by comprising the aqueous resin dispersion produced by the above production method.

The silicone macromonomer used in the present invention is a high molecular weight monomer having a silicone skeleton having a radically polymerizable group at the terminal, and its preferable number average molecular weight is measured by gel permeation chromatography. The polystyrene-equivalent number average molecular weight is 1,000 to 100,000, preferably 2,0.
00 to 50,000. This number average molecular weight is 1,
If it is less than 000, the branch polymer in the obtained graft polymer is too short, and the properties derived from silicone such as lubricity, releasability, and weather resistance are difficult to develop, while 100,0
When it exceeds 00, the copolymerizability with the vinyl monomer to be copolymerized is poor and the yield of the graft polymer is lowered. Examples of the radically polymerizable group bonded to the terminal of the silicone skeleton include an acryloyl group, a methacryloyl group, a styryl group, an allyl group, a vinylbenzyl group, a vinyl ether group, a vinylalkylsilyl group, a vinylketone group and an isopropenyl group.

The above radical polymerizable silicone macromonomer can be produced by a known method. For example, a method in which a living polymer is obtained by anionically polymerizing a cyclic siloxane using lithium trialkylsilanolate as a polymerization initiator, and this is reacted with γ-methacryloxypropyldimethylmonochlorosilane to synthesize (Japanese Patent Laid-Open No. 59-78236). Japanese Patent Laid-Open Publication No. JP-A-2003-242242, and a method of obtaining a silicone-based macromonomer as a condensation reaction product of a terminal silanol group-containing silicone and an organosilicon compound (JP-A-2000-242242).
58-167606, JP-A-60-123518, etc.) can be used.

In the present invention, the monomer to be copolymerized with the silicone macromonomer may be any vinyl monomer or vinyl monomer mixture that can be emulsified in an aqueous medium, and is a hydrophobic one that is liquid at room temperature. Is preferably used. Specifically, methyl methacrylate, ethyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, tertiary butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl ( (Meth) acrylates such as (meth) acrylate, behenyl (meth) acrylate, isobornyl (meth) acrylate, fluorine-containing (meth) acrylates such as polyfluoro (meth) acrylate, perfluoro (meth) alkyl acrylate, and (meth) acryloyl Silicone-containing acrylates such as oxypropyltrimethoxysilane, styrene, α-methylstyrene, p-
Examples thereof include styrene compounds such as methylstyrene, vinyl esters such as (meth) acrylonitrile, vinyl acetate and vinyl propionate.

Other vinyl monomers can be used in combination with the above vinyl monomers. Examples of vinyl monomers that can be used in combination include methyl acrylate, 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, (meth) acrylamide, and N-.
Hydrophilic vinyl monomers such as methylol (meth) acrylamide, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, (meth) acrylic acid, vinylpyrrolidone and vinylpyridine, divinylbenzene, diallyl phthalate and Examples thereof include polyfunctional vinyl monomers such as diethylene glycol diacrylate, stearyl (meth) acrylate, behenyl (meth) acrylate, maleic anhydride, butadiene, isoprene and vinylidene chloride.

The silicone macromonomer is used in a state of being dissolved in the vinyl monomer, and its preferable copolymerization ratio is 1 to 50% by weight of the silicone macromonomer.
The vinyl monomer is in the range of 50 to 99% by weight. If the proportion of the silicone macromonomer exceeds 50% by weight, gelation is likely to occur during polymerization. When a polyfunctional vinyl monomer is used as a part of the copolymerizable monomer, the amount of the polyfunctional vinyl monomer is preferably 5% by weight or less based on the total amount of all monomers. Is preferred.

The polymeric emulsifier used in the present invention is (a) a macromonomer having a (meth) acryloyl group at the end of a silicone molecule, that is, a silicone macromonomer, (b) an α, β-ethylenically unsaturated carboxylic acid. A graft copolymer obtained by copolymerizing an acid and (c) another radically polymerizable monomer is a water-soluble graft copolymer obtained by neutralizing a part or all of the carboxyl groups with a base.

The macromonomer used as the component (a) in the polymer emulsifier is basically the same as the above-mentioned silicone macromonomer, and the preferable amount of the silicone unit in the polymer emulsifier is 5 to 60% by weight. More preferably, it is 10 to 50% by weight. When a polymer emulsifier having a proportion of silicone units less than 5% by weight is used, the polymerization of the silicone macromonomer and the copolymerizable vinyl monomer becomes unstable in an aqueous medium. On the other hand, when the amount of the silicone unit exceeds 60% by weight, the water-solubility of the polymer emulsifier is insufficient and the emulsifying performance becomes poor.

Examples of the α, β-ethylenically unsaturated carboxylic acid which can be used as the component (b) include acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid and maleic anhydride. Can be mentioned. The preferred amount of the α, β-ethylenically unsaturated carboxylic acid used is such that the acid value of the graft copolymer is 30 to 260 mgKOH / g resin. The amount of the α, β-ethylenically unsaturated carboxylic acid that gives the acid value range varies depending on the type of the unsaturated carboxylic acid used, but it is usually 3 to 40% by weight based on the total amount of all radically polymerizable components used for the polymerization. %. When the acid value of the graft copolymer is less than 30 mgKOH / g resin, the graft copolymer cannot be water-solubilized even if neutralized with a base, and a film composed of an aqueous resin dispersion obtained when the graft copolymer exceeds 260 mgKOH / g resin. The water resistance of will decrease.

The component (c) constituting the polymer emulsifier is methyl (meth) acrylate, ethyl (meth) acrylate,
Propyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, pentyl (meth) acrylate,
Hexyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, behenyl (meth) acrylate, cyclohexyl (meth) acrylate Benzyl (meth) acrylate, phenyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, polyalkylene glycol (meth) acrylate,
(Meth) acrylic acid esters such as glycidyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, perfluoroalkyl (meth) acrylate, styrene,
Aromatic vinyl compounds such as vinyltoluene and α-methylstyrene, (meth) acrylonitrile, vinyl acetate, vinyl propionate, N-methylol (meth) acrylamide, vinyl chloride, vinyl fluoride, vinylidene chloride, vinylidene fluoride, trichloroethylene. Etc., and these can be used alone or in combination of two or more. Among these, it is preferable to use a monomer whose main component is (meth) acrylic acid alkyl ester. A preferred ratio of the radical polymerizable monomer unit in the graft copolymer is 10 to 96% by weight.

The components (a), (b) and (c) are copolymerized by a known polymerization means such as a radiation irradiation method or a method using a radical polymerization initiator. Considering the simplicity of the polymerization operation and the ease of adjusting the molecular weight of the resulting graft copolymer, the method using a radical polymerization initiator is preferred, and the solution polymerization method using an organic solvent is more preferred. Examples of the solvent in the solution polymerization method include ketone solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone, acetic acid ester solvents such as ethyl acetate and butyl acetate, alcohol solvents such as methanol, ethanol and isopropanol.

As the radical polymerization initiator used in the above-mentioned polymerization, an inorganic radical polymerization initiator such as ammonium persulfate or hydrogen peroxide, 2,2'-azobisisobutyronitrile, 2,2'-azobis (2- (Methyl butyronitrile), benzoyl peroxide, lauroyl peroxide, and other organic radical polymerization initiators. In order to adjust the molecular weight of the graft copolymer, mercaptoacetic acid, mercaptopropionic acid, 2-propanethiol, 1-butanethiol, 2-methyl-2-propanethiol, 2
-A chain transfer agent such as mercaptoethanol, ethylmercaptoacetate, thiophenol, 2-naphthalenethiol, dodecylmercaptan or thioglycerol may be appropriately added to the polymerization system. The polymerization temperature is 60 to 1
The temperature is preferably 00 ° C., and the polymerization time is suitably 3 to 10 hours.

The polymeric emulsifier is a water-soluble graft copolymer obtained by adding a base to an organic solvent solution of a carboxyl group-containing graft copolymer obtained by the above polymerization to neutralize a part or all of the carboxyl groups. Is prepared. Examples of the base include inorganic alkali metal bases such as sodium hydroxide and potassium hydroxide, ammonia, or triethylamine, trimethylamine, diisopropylamine, monoethanolamine, diethanolamine, triethanolamine, dimethylethanolamine and the like. The neutralization amount of the carboxyl group is preferably 50 mol% or more, and when it is less than 50 mol%, it becomes difficult to convert the graft copolymer into water-soluble. In order to further improve the water resistance of the film, it is preferable to apply ammonia, triethylamine, or dimethylethanolamine, which does not easily remain during the film formation.

The polymer emulsifier comprising the above water-soluble graft copolymer is used by adding it to water as a polymerization medium at the time of producing an aqueous resin dispersion. The preferred amount used is in the range of 1 to 100% by weight based on the total amount of the monomers used for producing the desired aqueous resin dispersion. If the amount used is less than 1% by weight, the silicone macromonomer having a hydrophobic radically polymerizable group cannot be emulsified and dispersed, and a stable aqueous resin dispersion cannot be obtained. On the other hand, if the amount used exceeds 100% by weight, the water resistance and the film strength of the film will decrease when the resulting aqueous resin dispersion is applied.

The radical polymerization initiator used for the copolymerization of the silicone macromonomer and other vinyl monomers in the present invention is not limited to water-soluble or oil-soluble one as long as it is generally used for radical polymerization. It is possible, and an appropriate one may be selected and used according to the polymerization conditions. For example, a persulfate polymerization initiator such as ammonium persulfate, 2,2′-azobisisobutyronitrile, 2,2 ′
-Azo polymerization initiators such as azobis (2-methylbutyronitrile), organic peroxide polymerization initiators such as benzoyl peroxide, lauroyl peroxide, cumene hydroperoxide, tert-butyl hydroperoxide, diisopropylbenzene It is possible to use a redox polymerization initiator obtained by combining an oxidizing agent composed of an organic hydroperoxide such as hydroperoxide and a reducing agent such as Rongalit, sodium hydrogen sulfite, and ascorbic acid. The amount of these radical polymerization initiators used is preferably 0.1 to 5% by weight based on the total amount of the silicone macromonomer and the copolymerized vinyl monomer.

The aqueous resin dispersion of the present invention is prepared by dissolving the silicone macromonomer having a radically polymerizable group in another vinyl monomer using the above-mentioned components, and preparing the resulting solution in an aqueous medium. It is produced by an operation of copolymerizing a silicone-based macromonomer and another vinyl monomer with a radical polymerization initiator in the presence of a molecular emulsifier. Specifically, an operation in which a polymeric emulsifier is dissolved in water and a solution in which a silicone macromonomer is dissolved in a vinyl monomer and a radical polymerization initiator are supplied from separate dropping routes while stirring the aqueous medium. Done in steps. At this time, a solution in which a silicone macromonomer is dissolved in a vinyl monomer may be emulsified and dispersed in water in advance and then supplied to the polymerization system. When an oil-soluble radical polymerization initiator is used, it is operably simple to dissolve the silicone macromonomer in a solution of a vinyl monomer and supply the radical polymerization initiator to the polymerization system.

The aqueous resin dispersion obtained by the above-mentioned production method is an aqueous emulsion in which a resin having an extremely fine particle size is emulsified and dispersed, has a transparent coating surface, and has various properties such as water repellency, antifouling and lubrication. Because of its excellent properties, it is particularly useful as a coating agent for magnetic tapes, heat-sensitive recording films, photosensitive recording films and the like.

[0027]

According to the present invention, when an aqueous resin dispersion is produced by subjecting a silicone-based macromonomer having a radically polymerizable group to another vinyl monomer by aqueous emulsion polymerization, silicone is used as an emulsifier as a hydrophobic unit. , A polymeric emulsifier consisting of a water-soluble graft copolymer having a specific composition with a carboxylate as a hydrophilic unit is selectively used, and the silicone macromonomer is dissolved in the copolymerizable vinyl monomer in an aqueous medium. By copolymerizing with a radical polymerization initiator in the presence of the polymer emulsifier, it is possible to easily produce an aqueous resin dispersion in which extremely fine resin particles are homogeneously emulsified and dispersed.

In the same polymerization method as described above, a known silicone type polymer surfactant [eg, KF354 (HLB; 18), KF353 (HLB; 10) manufactured by Shin-Etsu Chemical Co., Ltd.,
KF6016 (HLB; 4.5) etc. Even if a nonionic surfactant composed of a graft copolymer of polydimethylsiloxane-polyethylene glycol is used as an emulsifier, a large amount of aggregates are generated during the polymerization as in Comparative Example 2 described later, and stable polymerization is performed. Was difficult.

The aqueous resin dispersion produced by the present invention is an extremely fine resin dispersion system and is an aqueous emulsion having good storage stability. The coating surface formed by the coating is transparent, and it is water-repellent and Although it is excellent in stain resistance, weather resistance, lubricity, releasability, etc., these physical properties can be achieved only by the specified combination of components of the present invention and the polymerization method.

[0030]

EXAMPLES Examples of the present invention will be specifically described below in comparison with comparative examples. The polymeric emulsifiers A and B used in each example were prepared by the following methods.

Polymer Emulsifier A; Butyl Methacrylate 5
5 parts by weight, 10 parts by weight of 2-hydroxyethyl methacrylate, 15 parts by weight of methacrylic acid and 100 parts by weight of methyl ethyl ketone were mixed. In this mixed solution, a silicone macromonomer having a methacryl group at the end of a silicone molecule [FMO725 manufactured by Chisso Corporation; number average molecular weight of about
10,000) 20 parts by weight, n-dodecyl mercaptan 1.0
Parts by weight, 1.0 parts by weight of 2,2′-azobisisobutyronitrile (hereinafter referred to as “AIBN”) are dissolved, and a stirrer,
A flask equipped with a condenser, a thermometer, and a nitrogen introduction tube was charged and heated at 80 ° C. for 4 hours in a nitrogen atmosphere, 0.5 part by weight of AIBN was further added, and the mixture was heated at the same temperature for 4 hours to obtain a nonvolatile content of 49.7. %, Acid value 100 mg KOH / g resin graft copolymer was synthesized. 100 g of 1.7% aqueous ammonia solution was gradually added to the obtained reaction solution while stirring, and the mixture was heated to a temperature of 50 ° C. under reduced pressure to distill off methyl ethyl ketone to obtain a polymeric emulsifier A having a pH of 7.7. Obtained.

Polymeric emulsifier B: Silicone macromonomer in which the polymerizable group at the molecular end is a methacryloyl group as a silicone macromonomer [manufactured by Toagosei Co., Ltd., A
K-32; number average molecular weight 20,000] 20 parts by weight, and using butyl acrylate 50 parts by weight, styrene 10 parts by weight and acrylic acid 20 parts by weight as a copolymerizable monomer, the obtained nonvolatile content is 49.8%, A solution of a graft copolymer having an acid value of 155 mg KOH / g resin was neutralized with 100 g of a 3.0% triethylamine aqueous solution. All other conditions were adjusted to pH 8.
Polymer Emulsifier B of 1 was obtained.

Example 1 35 parts by weight of methyl methacrylate, 35 parts by weight of butyl acrylate, 10 parts of 2-hydroxyethyl methacrylate
20 parts by weight of a mixed solution of a terminal methacryloyl group-type silicone macromonomer [manufactured by Chisso Corporation, FMO725] 20
A part by weight was dissolved to prepare a mixed solution. 100 parts by weight of deionized water and 60 parts by weight of polymeric emulsifier A were added to a flask equipped with a stirrer, a condenser, a thermometer, and a nitrogen introducing tube, heated to 60 ° C. under a nitrogen atmosphere, and then stirred under liquid stirring. 5 parts by weight of a 10% by weight aqueous solution of tert-butyl hydroperoxide, 5 parts by weight of a 10% by weight aqueous solution of Rongalit and 100 parts by weight of the monomer mixed solution were added dropwise over 4 hours. After the dropping, the reaction was continued for another 2 hours at the same temperature to complete the polymerization. In addition to the slight adhesion of agglomerates to the wall of the flask during the polymerization reaction, phenomena such as separation and blocking did not occur, and it was stable.

As a result of filtering the obtained aqueous resin dispersion through a 200-mesh net, the grid amount was 100 ppm or less, and it was confirmed that the system was a dispersion system of fine resin particles. The aqueous resin dispersion showed excellent storage stability with almost no precipitates even after standing for 1 month at room temperature. The polystyrene-reduced number average molecular weight of the obtained resin was measured by gel permeation chromatography to find that it was 20,000,000, and the weight average molecular weight was 132,000. The average particle size of the dispersed resin was 0.15 μm, and its distribution was narrow [measured with a laser diffraction particle size distribution analyzer LA-910 manufactured by Horiba, Ltd.]. Next, the above aqueous resin dispersion was applied to a glass plate so that the film thickness was 20 μm, and the transparency was measured with a haze meter (in accordance with JIS K-6714). The sex was good.

Example 2 In a mixed solution of 50 parts by weight of butyl methacrylate, 30 parts by weight of 2-ethylhexyl acrylate, 10 parts by weight of acrylonitrile, 1 part by weight of N-methyl acrylamide and 9 parts by weight of 2-hydroxymethyl methacrylate,
10 parts by weight of terminal methacryloyl group-type silicone macromonomer [AK-32 manufactured by Toagosei Co., Ltd.] was dissolved.
To this mixed solution, 60 parts by weight of the polymeric emulsifier B was added and emulsified in 40 parts by weight of deionized water using a three-one motor to prepare an aqueous emulsion dispersion (hereinafter referred to as "pre-emulsion"). The obtained pre-emulsion did not separate even after 1 day and was a stable emulsion. The average particle size of the dispersed resin particles was 1.65 μm, and the particle size distribution was narrow. Next, 60 parts by weight of deionized water was placed in a flask equipped with a stirrer, a thermometer, and a condenser, the liquid temperature was maintained at 70 ° C. while nitrogen was bubbled, and ammonium persulfate / deionized water = 0.7 while stirring. Parts by weight / 9.
After 3 parts by weight of 10 parts by weight of liquid and 200 parts by weight of pre-emulsion were added dropwise over 4 hours, the reaction was further continued for 2 hours to complete the polymerization. During the polymerization, there was no separation, blocking, etc., except that a few agglomerates were attached to the wall of the flask, and it was stable.

As a result of filtering the obtained aqueous resin dispersion through a 200-mesh net, the grid amount was 100 ppm or less, and the storage stability of the resin dispersion was good. The polystyrene equivalent number average molecular weight measured by gel permeation chromatography of the dispersion resin was 252,000, and the weight average molecular weight was 155,000.
The average particle size of the dispersed resin was 0.11 μm, and its distribution was narrow. This aqueous resin dispersion was applied onto a glass plate so that the film thickness was 20 μm, and the transparency was measured by a haze meter. The haze was 0.7, and the transparency was good.

Comparative Example 1 Instead of the polymeric emulsifier B in Example 2, 2.0 parts by weight of sodium di-2-ethylhexyl sulfosuccinate and 5.0 parts by weight of polyoxyethylene nonylphenyl ether of HLB 15.5 were used as emulsifiers. Emulsion polymerization to obtain an aqueous resin dispersion was carried out by using a pre-emulsion which was emulsified and dispersed by a homomixer to have an average particle size of 0.46 μm and other conditions were the same as in Example 2. As a result of filtering the obtained aqueous resin dispersion through a 200-mesh net, the grid amount was 100 ppm or less,
The storage stability of the resin dispersion was also good. The average particle size of the dispersion was 0.41 μm, but when the aqueous resin dispersion was applied to a glass plate so as to have a film thickness of 20 μm, it was confirmed that the coating film was cloudy. When this transparency was measured with a haze meter, the haze was 22.7.
Met.

Comparative Example 2 Instead of the polymeric emulsifier A in Example 1, a graft copolymer of polydimethylsiloxane-polyethylene glycol [KF354 (HLB; 18) 30 manufactured by Shin-Etsu Chemical Co., Ltd.]
% By weight is used as emulsifier, other conditions are in Example 1
When emulsion polymerization was carried out in the same manner as above to obtain an aqueous resin dispersion, a large amount of aggregates were generated during the polymerization, and the reaction system became very unstable. Therefore, the emulsion polymerization was stopped halfway.

[0039]

According to the present invention, it is possible to obtain a silicone-based aqueous resin dispersion having excellent physical properties, which is composed of a resin having a fine particle size, without the complicated processing operation of reducing the particle size of the pre-emulsion. The water-based resin dispersion obtained by the present invention is excellent in various properties such as water repellency, lubrication, mold release, antifouling, weather resistance, gas permeation, etc. , Graffiti prevention, paper sticking prevention, icing prevention,
Prevention of snow accretion, weather resistance, etc., coating agent (magnetic tape,
It is preferably used for heat-sensitive recording films, photosensitive recording films, etc.), adhesives, adhesives, sealing agents, polishes, dispersion improvers such as pigments and fillers, antistatic agents and resin modifiers.

Claims (2)

[Claims] 1. A solution prepared by dissolving a silicone-based macromonomer having a radical-polymerizable group in another vinyl monomer having a copolymerizability with the macromonomer, and (a) forming a (meth) acryloyl group at the terminal of the silicone molecule. A macromonomer having (b) an α, β-ethylenically unsaturated carboxylic acid and
(c) Presence of a polymeric emulsifier consisting of a water-soluble graft copolymer obtained by neutralizing a part or all of the carboxyl groups in the graft copolymer obtained by copolymerizing other radically polymerizable monomers with a base. A method for producing an aqueous resin dispersion, which comprises dispersing under an aqueous medium and copolymerizing the silicone macromonomer with another vinyl monomer using a radical polymerization initiator. 2. A coating agent comprising an aqueous resin dispersion produced by the production method according to claim 1.