JP2002069365A - Aqueous coating material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aqueous coating material capable of forming coating film having excellent water resistance and alkali resistance, and to be used for building materials, pottery and inorganic building materials. SOLUTION: The aqueous coating material contains a core/shell-type emulsion (A) and a pigment paste. The core/shell-type emulsion is an emulsion of a radical polymerization polymer (II) obtained by manufacturing a radical polymerization polymer (I) through a radical emulsion polymerization reaction of the first stage of a radical-polymerizable unsaturated monomer (1) in an aqueous solution consisting of water and an emulsifying agent in the presence of a tradical polymerization initiator, and subsequently subjecting a radical- polymerizable unsaturated monomer (2) to the radical emulsion polymerization reaction of the second stage in the presence of the obtained radical polymerization polymer (I). The monomer (1) is a radical-polymerizable unsaturated monomer having an alkoxysilyl group which contains 1-5 wt.%, for example, of trimethoxymethylsilane (a). The monomer (2) contains 1-3 wt.% of an alkoxysilyl group-containing radical-polymerizable unsaturated monomer (a1).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention forms a coating film having extremely excellent properties such as water resistance, moisture resistance, alkali resistance, adhesion to a substrate, and adhesion to a top coating film or an old coating film. The present invention relates to a water-based paint comprising a core / shell type emulsion.

[0002]

2. Description of the Related Art In recent years, in the field of paints, inks, adhesives, and the like, particularly in paints, when building or repainting roof tiles and outer walls of buildings, cracks on tiles and outer walls are likely to occur. To prevent rainwater intrusion, and to penetrate and adhere to porous materials (inorganic building materials) to improve the surface strength of the material. Such functions are required.

[0003] However, such as the recent "friendly to the environment and people",
Resource conservation, environmental hygiene, pollution-free and non-hazardous materials have been removed from consideration for the environment and people, and the medium used for diluting paints and adjusting viscosity has been shifting from organic solvents to water (aqueous).

[0004] Conventionally, aqueous paints have been formulated with emulsions obtained by emulsion polymerization of radically polymerizable unsaturated monomers in aqueous paints to form coatings having relatively good durability. However, due to the maintenance-free, long-term guarantee of coating film deterioration, and the frequent use of material shapes (porosity and pattern changes), conventional water-based paints with emulsion compositions have poor water permeability, water resistance, alkali resistance, etc. It was inadequate and improvements were urgent.

[0005]

Means for Solving the Problems The present inventors have conducted intensive studies in order to solve the above-mentioned problems, and as a result, the radical polymerizable unsaturated monomer having an alkoxysilyl group in an aqueous paint is essential. By mixing a radical polymerizable unsaturated monomer as a component with a core part and / or a shell part emulsion containing a radical copolymer obtained by emulsion polymerization, preferably a seed polymerization method, The inventors have found that the problems can be solved, and have completed the present invention. That is, the present invention provides: [1]: The radical polymerizable unsaturated monomer (1) is subjected to a first-stage radical emulsion polymerization reaction with a radical polymerization initiator (d) in an aqueous solution of water and an emulsifier (c) to form a radical polymer. After producing the union (I), the radical polymerizable unsaturated monomer (2) is obtained by performing the second-stage radical emulsion polymerization reaction in the presence of the obtained radical polymer (I). An emulsion of the radical polymer (II) obtained, wherein the radical polymerizable unsaturated monomer (1) is a radical polymerizable unsaturated monomer (a) having an alkoxysilyl group and other radical polymerizable monomers. Unsaturated monomer (b)
And the radical polymerizable unsaturated monomer (2) is
A radically polymerizable unsaturated monomer (a ₁ ) having an alkoxysilyl group and another radically polymerizable unsaturated monomer (b ₁ ), further comprising a radically polymerizable unsaturated monomer having an alkoxysilyl group (A) or (a ₁ ), a core / shell emulsion (A) containing the radically polymerizable unsaturated monomer (1) and / or the radically polymerizable unsaturated monomer (2), and [2] ]: Water-based paint containing pigment paste (B), In the core / shell type emulsion (A), the mixing ratio of the radical polymerizable unsaturated monomer (1) and the radical polymerizable unsaturated monomer (2) is determined based on the total weight of the solid content. 2. The aqueous coating composition according to item 1, wherein the content of the saturated monomer (1) is in the range of 10 to 90% by weight and the content of the radically polymerizable unsaturated monomer (2) is in the range of 90 to 10% by weight. In the core / shell type emulsion (A), the glass transition temperature (Tg) of the radical polymer (I) is from -20 ° C to
A glass transition temperature (Tg) of the radical polymer (II) in the range of 50 ° C. to 100 ° C., and a glass transition temperature (Tg) of the radical polymer (I) and the radical polymer (II). 3. The water-based paint according to item 1 or 2, wherein a difference between the water-based paints is 30 ° C to 120 ° C. In the core / shell type emulsion (A), the ratio of the radical polymerizable unsaturated monomer (a) having an alkoxysilyl group in the total solid content of the radical polymerizable unsaturated monomer (1) is 1 to 5% by weight. %, The proportion of the radical polymerizable unsaturated monomer (a ₁ ) having an alkoxysilyl group in the total solid content of the radical polymerizable unsaturated monomer (2) is 1 to
4. The water-based paint according to any one of items 1 to 3, which is in a range of 3% by weight.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The water-based paint of the present invention can be used for any of undercoating to topcoating paints, but is particularly suitable for construction such as slate board, calcium silicate board, ALC board, cement mortar surface, and wood surface. Materials, residential building materials, porous materials, and more specifically, a composition containing cement as a main component, and blended with reinforcing fibers such as pulp and rock wool, siliceous materials such as silica sand, and inorganic fillers It is preferably used as an inorganic hardening material (for example, an asbestos cement board, a wood chip cement board, a pulp cement board, a light-weight aerated concrete board) formed by a method or press molding or the like and water-hardened.

The coating composition is an aqueous coating obtained by mixing and stirring the core / shell emulsion (A), the pigment paste (B), the neutralized amine, other additives, and water.

First, a core / shell type emulsion (A)
As the emulsion polymerization method, there are an emulsion polymerization method, a suspension polymerization method, a seed polymerization method, a dispersion polymerization method, and the like, and any of these methods can be used for polymerization. The seed polymerization method is preferred from the following aspects.

In the seed polymerization method, the seed particles obtained by the first-stage reaction are used as a core, and the seed particles are swollen with a solvent and a radical polymerizable unsaturated monomer. In this method, seed particles, that is, a core / shell type emulsion are further grown by polymerization.

In this seed polymerization method, particles of a core / shell emulsion having a uniform and sharp particle size distribution can be obtained by polymerizing appropriate core particles. The average particle size of the core / shell emulsion of the present invention is in the range of 0.1 to 0.3 μm,
The use of this seed polymerization method is easy to adjust and is an excellent method for preparing an emulsion having a sharp average particle size distribution.

If the average particle size of the core / shell type emulsion is less than 0.1 μm, the ratio of the core / shell becomes non-uniform, and the stability becomes a problem. The average particle size is 0.
If it exceeds 3 μm, the emulsion particles will fuse together and impair the stability over time.

Next, the preparation of the core / shell type emulsion (A) by the seed polymerization method will be described in detail. The core / shell type emulsion (A) is prepared by mixing an alkoxysilyl group-containing radically polymerizable unsaturated monomer (a) and another radically polymerizable unsaturated monomer (A) in an aqueous solution of water and an emulsifier (c). a first-stage radical polymerization reaction of the radically polymerizable unsaturated monomer (1) comprising b) in the presence of an emulsifier (c) and a radical polymerization initiator (d),
That is, an emulsion polymerization reaction by a seed polymerization method is performed to form a core portion which is a radical polymer (I).

Then, in the presence of the obtained radical polymer (I), a radical polymerizable unsaturated monomer (a ₁ ) having an alkoxysilyl group and another radical polymerizable unsaturated monomer (b ₁ ) Is subjected to emulsion polymerization by a second-stage seed polymerization method to obtain a shell portion as a radical polymer (II).

Through the above-described production steps, a core / shell emulsion (A) having the radical polymer (I) as a core and the radical polymer (II) as a shell is produced.

The radically polymerizable unsaturated monomer (a) containing an alkoxysilyl group in the radically polymerizable unsaturated monomer (1) used in the first stage reaction is, for example, trimethoxyvinylsilane, trimethoxyvinylsilane or trimethoxyvinylsilane. Ethoxyvinylsilane,
Triisopropoxyvinylsilane, γ-methacryloyloxypropyltrimethoxysilane, γ-methacryloyloxypropyltriethoxysilane, γ-methacryloyloxypropyltriethoxysilane, γ-methacryloyloxypropyltriisopropoxysilane, γ-
Examples thereof include methacryloyloxypropyldimethoxymethylsilane and γ-methacryloyloxypropyldimethoxydimethylsilane, and these can be used alone or in combination of two or more. The other radically polymerizable unsaturated monomer (b) is not particularly limited. For example, 2-hydroxyethyl (meth) acrylate, 1,
6-hexanediol diacrylate, allyl methacrylate, addition product of 2-hydroxypropyl (meth) acrylate and caprolactone (manufactured by Daicel Chemical Industries, Ltd.
Hydroxyl group-containing radically unsaturated monomers such as trade names, Placcel FA and FM series); carboxyl group-containing radically unsaturated monomers such as acrylic acid, itaconic acid and methacrylic acid; methyl methacrylate, ethyl methacrylate, and methacrylic acid Alkyl esters of (meth) acrylic acid such as propyl acrylate, butyl methacrylate, ethyl acrylate, and n-butyl acrylate, styrene, acrylonitrile, acrylamide, stearyl acrylate, stearyl methacrylate, dimethylaminoethyl methacrylate, and cyclohexyl methacrylate. . These can be used alone or in combination of two or more, like the radically polymerizable unsaturated monomer (a) containing an alkoxysilyl group.

The radically polymerizable unsaturated monomer (a) containing an alkoxysilyl group is 1 to 5% by weight based on the total weight of the radically polymerizable unsaturated monomer (1). A range is preferred. If the amount of the radically polymerizable unsaturated monomer (a) is less than 1% by weight, particles cannot be formed. If the amount of the radically polymerizable unsaturated monomer (a) exceeds 5% by weight, seeds cannot be obtained. The polymerization reaction becomes insufficient.

The emulsifier (c) used in the emulsion polymerization reaction includes an anionic emulsifier, a nonionic emulsifier and a zwitterionic emulsifier.

Examples of the anionic emulsifier include alkyl sulfates, alkyl benzene sulfonates, alkyl phosphates and the like.

Examples of the nonionic emulsifier include polyoxyethylene alkyl ethers, polyoxyethylene derivatives, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene alkylamines, and alkyl alkanolamides. No. For example, polyoxyethylene oleyl ether, polyoxyethylene stearyl ether,
Polyoxyethylene lauryl ether, polyoxyethylene tridecyl ether polyoxyethylene phenol ether, polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene monolaurate, polyoxyethylene monostearate, polyoxyethylene mono Oleate, sorbitan monolaurate, sorbitan monostearate,
Sorbitan monostearate, sorbitan triolate, polyoxyethylene sorbitan monolaurate, polyoxyethylene octyl phenyl ether, and the like.

Examples of the zwitterionic emulsifier include dimethylalkylbedines, dimethylalkyllaurylbedines, alkylglycines and the like.

The concentration of the anionic emulsifier, the nonionic emulsifier, and the zwitterionic emulsifier is preferably 0.1 to 0.1 with respect to the total weight of the solid content of the radically unsaturated monomer (1).
The range is 10% by weight, preferably 1 to 5% by weight.

Examples of the radical polymerization initiator (d) include ammonium persulfate 4,4'-azobis (4-cyanobutanoic acid) and the like. The initiator used for emulsion polymerization is 0.01 to 10% by weight. % Is better. The reaction is carried out under the conditions of a reaction time of 3 hours and a reaction temperature of 80 ° C., preferably a reaction time of 4 hours and a reaction temperature of 80 ° C.

In the present invention, the water-based paint is water-resistant, water-resistant,
As having good alkali resistance, S of the alkoxysilyl group forming the core part which is the radical polymer (I)
i is Si—O as represented by the following reaction formula (1):
-Si (siloxane) bonds are present in the particles,
It is thought that this improves the crosslink density of the core portion and contributes to the improvement of the physical properties at the time of forming the coating film.

Reaction Formula (1) Si—OR → Si—OH 2SiOH → Si—O—Si Next, the shell portion is produced by a second-stage seed polymerization reaction. The radical copolymerizable unsaturated monomer (2) contains a radical polymerizable unsaturated monomer (a ₁ ) having an alkoxysilyl group as an essential component, and contains other radical polymerizable unsaturated monomers (b _1). ).

In the radical copolymerizable unsaturated monomer (2), a radical polymerizable unsaturated monomer (a ₁ ) having an alkoxysilyl group and another radical polymerizable unsaturated monomer (b ₁ ) can be used alone or in combination of two or more. As the emulsifier (c) and the radical polymerization initiator (d), the same ones as used in the polymerization of the radical polymer (I) can be used, or they may be different.

The radical polymerizable unsaturated monomer (a ₁ ) having an alkoxysilyl group is in the range of 1 to 3% by weight based on the total solid content of the radical polymerizable unsaturated monomer (2). . If the amount of the radically polymerizable unsaturated monomer (a ₁ ) is less than 1% by weight, it cannot be formed into particles, and the amount of the radically polymerizable unsaturated monomer (a ₁ ) exceeds 3% by weight. And the polymerization reaction becomes insufficient.

The core / shell emulsion prepared as described above is characterized by the radical polymer (I),
That is, the glass transition temperature (Tg) of the core is −20.
C. to 20.degree.

The glass transition temperature (Tg) of the core is -20.
When the temperature is lower than 20 ° C., the blocking property deteriorates, and when the Tg exceeds 20 ° C., the film forming property deteriorates.

The glass transition temperature (Tg) of the radical polymer (II), ie, the shell portion, is in the range of 40 ° C. to 100 ° C. When the Tg of the shell portion is less than 40 ° C., the blocking property is deteriorated, and the glass transition temperature (Tg) is 10%.
If the temperature exceeds 0 ° C., the film-forming properties deteriorate.

In the core / shell type emulsion, the glass transition temperature (Tg) of the shell portion is 30 to 120 ° C., preferably 50 ° C., as compared with the glass transition temperature of the core portion.
It is preferable that the temperature is higher by 100 ° C. As a result, the film forming property and the blocking property of the paint are improved, and the stability is improved.

If the difference of the glass transition temperature (Tg) is less than 30 ° C., the boundary between the core and the shell becomes unstable, and if it exceeds 120 ° C., the emulsion becomes hard and the fusion property between the emulsions becomes poor. Because of the decrease, the coating film of the water-based paint is easily peeled off. In this specification, the glass transition temperature (Tg) of the polymer can be calculated by the following equation.

1 / Tg (゜ K) = (W / T) + (W / T) + · Tg (° C) = Tg (゜ K) -273 In the formula, W, W,. , T, T,... Each represent the Tg (ΔK) of the homopolymer of the monomer. Note that T, T,.
・ Polymer Hand Book (Scon
d Edition, J.M. Brandup E. H. I
(mergut). When the Tg of the homopolymer of the monomer is not clear, the glass transition temperature (° C) is calculated using a vibron dynamic viscoelastic device
Using NAMIC VISCO ELASTOMETER MODELVIBRON DDV-IIEA type (TOYO BACDWIN CO. Ltd.), frequency 110H
The sample was measured on a polypropylene plate and then on the isolated coating film according to z, the dynamic glass transition temperature (° C.) at a heating rate of 3 ° C./min.

The average particle size (Note 1) of the core / shell type emulsion is in the range of 0.1 to 0.3 μm. If the average particle size is less than 0.1 μm, the balance between the core and the shell is poor, and the stability is poor. In addition, the average particle size is 0.
If it exceeds 3 μm, the emulsion particles are fused and the stability is impaired. (Note 1) Average particle size: Performed using Nanosizer N4 (manufactured by Coulter).

The content of Si contained in the core of the core / shell emulsion is preferably 1 to 2% by weight based on the total solid content of the radically polymerizable unsaturated monomer (1). If the content is less than 1% by weight, emulsion particles cannot be formed, and if it exceeds 2% by weight, the stability during polymerization becomes poor.

As the content of Si contained in the shell portion,
The content of the radical polymerizable unsaturated monomer (2) is preferably in the range of 1 to 1.5% by weight based on the total solid content. When the content of Si is less than 1% by weight, the particles are not cured and the gel fraction is low. I can't get it. On the other hand, if the Si content exceeds 1.5% by weight, the storage stability of the emulsion deteriorates, so that the heat flow property of the coating film deteriorates and the finish property deteriorates.

The weight ratio of the core part to the shell part of the core / shell emulsion is 10 to 90% by weight, especially 20 to 80% by weight based on the total solid content of both components.
% By weight, and the shell portion is 90 to 10% by weight, particularly 80 to 20% by weight.
A weight percent range is suitable. When the ratio of the core portion is 10% by weight or less, the coating does not have a film-forming property. Also,
If the ratio of the core portion exceeds 90% by weight, tackiness is exhibited, and the blocking property of the coating material is reduced.

In the radically polymerizable unsaturated monomer (1) and the radically polymerizable unsaturated monomer (2) constituting the core and the shell, the core and the shell have the above-mentioned properties. Radical polymerizable unsaturated monomer having an alkoxysilyl group (a), other radical polymerizable unsaturated monomer (b), radical polymerizable unsaturated monomer having an alkoxysilyl group (a ₁ ), etc. From the radical polymerizable unsaturated monomers (b ₁ ).

The aqueous coating composition of the present invention can be used as a clear coating film by using the above-mentioned core / shell type emulsion as it is. Generally, if necessary, a pigment paste (B), a neutralizing agent, It is used as a water-based paint by blending other additives.

The pigment paste (B) is mainly composed of a pigment such as a dispersing resin, a coloring pigment and an extender, and water. Other additives such as an antifoaming agent, a surface conditioner, a preservative, and an organic Solvents, water-soluble resins, plasticizers, defoamers, thickeners, surface tension regulators, anti-settling agents, film-forming aids, preservatives, ultraviolet absorbers,
It is also possible to disperse a light stabilizer and the like together with other pigments and mix them in a pigment paste.

Examples of the dispersion method include a sand mill, a ball mill, a despar, and a shaker. As the dispersing resin in the pigment paste (B), a conventional dispersing resin such as an acrylic resin, an epoxy resin, a polycarboxylic acid resin, or a polyester can be used.

As the coloring pigment, titanium oxide, zinc white,
White pigments such as lead white, basic lead sulfate, lead sulfate, lithopone, zinc sulfide, antimony white; black pigments such as carbon black, acetylene black, lamp black, bone black, graphite, iron black, aniline black; naphthol yellow S Yellow pigments such as hansa yellow, pigment yellow L, benzidine yellow and permanent yellow; orange pigments such as chrome orange, chromium vermillion and permanent orange; brown pigments such as iron oxide and amber; Red pigments such as red pigments; purple pigments such as cobalt violet, fast violet and methyl violet lakes,
Ultramarine, navy blue, cobalt blue, phthalocyanine blue,
Blue pigments such as indigo; green pigments such as chrome green, pigment green B and phthalocyanine green.

Examples of extenders include barita powder, precipitated barium sulfate, barium carbonate, calcium carbonate, gypsum, clay, silica, white carbon, diatomaceous earth, talc, magnesium carbonate, alumina white gloss white, red rust,
Ocher, mica powder and the like. As antirust pigments, zinc chromate, strontium chromate, calcium chromate, lead cyanamide, calcium leadate,
Zinc phosphate and the like can be mentioned.

Other metal powder pigments and metal luster pigments include aluminum powder, bronze powder, copper powder, tin powder, lead powder, zinc powder, iron phosphide, pearl-like metal-coated mica powder, and mica-like iron oxide. No.

The mixing ratio of the pigment paste (B) varies depending on the type of the pigment used and the required color density, but the solid content of the core / shell type emulsion (A) is 100%.
Usually, the range of 2 to 200 parts by weight with respect to parts by weight is preferable.

As the kind of the neutralizing amine, ammonia,
Triethylamine, dimethylaminoethanol, 2-amino-2-methyl-1-propanol and the like,
The mixing ratio is preferably in the range of 0.01 to 10 parts by weight based on 100 parts by weight of the solid content of the core / shell type emulsion (A), and is added to adjust the pH of the water-based paint to 7 to 9.

As other additives, as mentioned above, defoaming agents, surface conditioners, preservatives, organic solvents, water-soluble resins, plasticizers, defoamers, thickeners, surface tensions Examples include a regulator, an anti-settling agent, a film-forming aid, a preservative, and the like, and two or more of them are used in combination depending on the purpose.

For example, one or two or more selected from alcohol components can be used as a film-forming auxiliary. Specific examples of such alcohol components include ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, and diethylene glycol monobutyl ether.
Teracetate, propylene glycol monomethyl ether
And propylene glycol monobutyl ether and dipropylene glycol normal butyl ether.

Further, (CH) CHCOOCHC (CH)
2,2,4-Trimethyl-1,3-pentanediole monoisobutyrate (Texanol) represented by C (OH) HCH (CH) is also used as a film-forming aid. The content of the film-forming aid is not particularly limited, but is in the range of 0.1 to 25 parts by weight, preferably 1 to 20 parts by weight, per 100 parts by weight of the resin solid content of the emulsion.

The coating method is not particularly limited, and a conventionally known coating method such as a roller, a brush, a dipping, an air spray, an electrostatic spray, a flow coater (curtain flow coater), or a roll coater can be used. .

The dry film thickness is in the range of 5 to 100 μm, preferably 10 to 80 μm. The drying condition is, for example, a normal drying oven, a hot air drying oven, a jet heater, or the like, and the ambient temperature is 50 to 200 ° C., preferably 70 to 150 ° C.
It is preferable to dry at about 10 seconds to 30 minutes, preferably about 20 seconds to 20 minutes, more preferably about 30 seconds to 10 minutes.

[0051]

EFFECTS OF THE INVENTION The water-based paint of the present invention does not contain a large amount of an organic solvent or the like, so it has high safety and low odor which is good for the environment. For the purpose, including roof tiles for houses,
It has excellent permeability and impregnation-hardening property to porous materials such as slate board, calcium silicate board, cement mortar surface, wood surface and other building materials, and can be used as an aqueous coating for these porous substrates. Further, the obtained coating film has excellent properties such as water resistance, moisture resistance, alkali resistance, adhesion to a substrate, and adhesion to a top coating film or an old coating film.

[0052]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples. The present invention is not limited to the embodiments. Note that “parts” and “%” indicate “parts by weight” and “% by weight”.

Production Example of Pigment Paste As a dispersing resin, 5 parts of DISPER BYK-190 (manufactured by BYK Chemie, trade name, dispersing resin), 34 parts of deionized water, 43 parts of titanium white, and 11 parts of monoazo yellow
Parts, 2 parts of quinacridone red, 10 parts of barium sulfate,
1 part of carbon black was added, and a pigment paste (B) was prepared in two passes using a desktop sand mill.

Emulsion NO. Production Example 1 A 2 liter four-necked flask was equipped with a condenser, a thermometer,
A dropping funnel was attached, and 50 parts of deionized water and 0.05 part of sodium dodecylbenzenesulfonate as an emulsifier were charged. After the inside air was replaced with nitrogen, the internal temperature was increased to 82 ° C. with stirring to dissolve. In a separate container, 37 parts of deionized water, 3 parts of sodium dodecylbenzenesulfonate as an emulsifier, and 0.15 parts of ammonium peroxodisulfate as a radical polymerization initiator were added and foamed well. A mixed solution of the radical unsaturated monomer (1) shown in Table 1 below was added thereto, and the mixture was stirred to form an emulsifier, which was continuously dropped into the reaction vessel over 3 hours, and the radical polymer ( I) was obtained.

Next, in a separate container, 16 parts of deionized water, 1.5 parts of sodium dodecylbenzenesulfonate and 0.05 part of ammonium peroxodisulfate were added, and the mixture was stirred well and foamed. The mixed solution of the radically unsaturated monomer (2) was added and stirred to form an emulsion. It was added dropwise over 1 hour to the reaction vessel of the radical polymer (I). After completion of the dropwise addition, the mixture was stirred at 82 ° C. for 2 hours, cooled to 40 ° C. and cooled to a core / shell type emulsion NO. Having a radical polymer (II) in a shell portion. 1 was obtained.

The solid content of the obtained emulsion is 51%,
The average particle diameter was 0.15 μm, the Tg of the core was −1 ° C., the glass transition temperature (Tg) of the shell was 75 ° C., and the difference between the core and the shell was 76 ° C.

Emulsion NO. 2 to NO. Production Example 4 Emulsion No. 4 was prepared in the same manner as in Example 1 with the composition shown in Table 1. 2 to NO. 4 was created. Average particle size,
The glass transition temperatures (Tg) of the core portion and the shell portion are similarly shown.

[0058]

[Table 1] Table 1 Emulsion formulation

Example 1 146 parts of pigment paste, emulsion NO. 1 22
2 parts, cellosolve solvent 10 parts, SN Deformer 777
(Manufactured by San Nopco, trade name, defoamer) 0.25 parts, BY
K-345 (manufactured by BYK Japan KK, trade name, surface conditioner) and 110.7 parts of clean water are mixed, stirred with a disper, 0.1 part of ammonia is added to adjust pH to 7.0, and solid content is adjusted. 40% aqueous paint NO. 1 was created.

Example 2, Comparative Examples 1 and 2 Emulsion NO. 2 to NO. 4
And an aqueous paint NO. 1 to NO. 4 was created.

[0061]

[Table 2]

Preparation of test plate and test results 1 to NO. 4 was applied to a slate plate using an airless spray so that the dry film thickness became 30 μm, and baked at 120 ° C. for 20 minutes with an electric hot air drier to obtain a dry coating film. Table 3 shows the results of performance tests using this test plate.

[0063]

[Table 3]

(Note 1) Water resistance: A test plate was obtained by coating the above coating material on a slate plate so as to have a film thickness of 50 μm. Using this test plate, the water resistance was evaluated by the funnel method of JIS K 5400.

(Note 2) Moisture permeability: The above coating material was applied to a tin plate to a thickness of 50 μm, and then the coating film was peeled off with amalgam to obtain a free coating film. Using this free coating film, a moisture permeability test of JIS Z 0208 was performed.

(Note 3) Blocking resistance: The painted surfaces of test plates prepared in the same manner as in the water resistance test were brought into contact with each other, and a load of 1 kg / cm ² was applied in an atmosphere of 40 ° C. Evaluation: State ◎: No blocking at all が あ る: Slight resistance but easily peeled and no trace left △: Resistant and trace left after peeling ×: Strongly blocked and not peeled

(Note 4) Topcoat adhesion: An IM coat 5111 (manufactured by Kansai Paint Co., trade name, acrylic water-based paint) was applied to a test plate prepared in the same manner as in the water resistance test.
Coating was performed so as to be 0 μm. This test plate was cut in 5 × 5 grids at intervals of 4 mm with a cutter knife and peeled off by attaching cellophane tape (registered trademark). Evaluation: State ◎: No peeled squares ○ : A little peeling can be seen along the cutting edge of the cutter knife. △: Peeling of the second square or less ×: Peeling of the third square or more

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Akira Numazawa 4-171-1, Higashi-Hachiman, Hiratsuka-shi, Kanagawa Prefecture Inside Kansai Paint Co., Ltd. (72) Inventor Masaaki Shinohara 4-171-1, Higashi-Hachiman, Hiratsuka-shi, Kanagawa Seki F-term (reference) in Nishi Paint Co., Ltd. NA04 NA12 PB05 PC04

Claims (4)

[Claims] [1] A first-stage radical emulsion polymerization reaction of a radically polymerizable unsaturated monomer (1) component with a radical polymerization initiator (d) in an aqueous solution of water and an emulsifier (c). To produce a radical polymer (I), and then, in the presence of the obtained radical polymer (I), the radical polymerizable unsaturated monomer (2) is subjected to a second-stage radical emulsion polymerization. An emulsion of the radical polymer (II) obtained by performing the reaction, wherein the radical polymerizable unsaturated monomer (1) is a radical polymerizable unsaturated monomer (a) having an alkoxysilyl group and The other radically polymerizable unsaturated monomer (b), and the radically polymerizable unsaturated monomer (2) is a radically polymerizable unsaturated monomer (a ₁ ) having an alkoxysilyl group; a radical polymerizable unsaturated monomer (b ₁₎ I, the radical polymerizable unsaturated monomer having a further alkoxysilyl group (a) or (a
₁ ) is a core / shell type emulsion (A) containing a radical polymerizable unsaturated monomer (1) and / or a radical polymerizable unsaturated monomer (2), and [2]: a pigment paste (B ). 2. In the core / shell emulsion (A), the mixing ratio of the radically polymerizable unsaturated monomer (1) and the radically polymerizable unsaturated monomer (2) is based on the total weight of the solid content. The radical polymerizable unsaturated monomer (1)
90% by weight of the radically polymerizable unsaturated monomer (2)
The water-based paint according to claim 1, which is in a range of 10 to 10% by weight. 3. In the core / shell type emulsion (A), the glass transition temperature (Tg) of the radical polymer (I) is in the range of −20 ° C. to 20 ° C., and the glass transition temperature (Tg) of the radical polymer (II) is 3) is in the range of 50 ° C to 100 ° C, and the difference between the glass transition temperatures (Tg) of the radical polymer (I) and the radical polymer (II) is 30 ° C to 120 ° C. Water-based paint. 4. The ratio of the radically polymerizable unsaturated monomer (a) having an alkoxysilyl group in the core / shell type emulsion (A) based on the total solid content of the radically polymerizable unsaturated monomer (1). Is 1 to 5% by weight, and the proportion of the radical polymerizable unsaturated monomer (a ₁ ) having an alkoxysilyl group in the total solid content of the radical polymerizable unsaturated monomer (2) is 1 to 3% by weight. The water-based paint according to any one of claims 1 to 3, which is in a range.