JPH06116528A - Aqueous dispersion for coating - Google Patents

Abstract

PURPOSE:To provide an aqueous dispersion for coating excellent in the adhesiveness, antifouling capability and hardness of the coating film therefrom, useful for application on automotive trim and facing materials, etc., consisting of an aqueous dispersion of a copolymer which is obtained by emulsion polymerization of each specific monomer in the presence of a reactive emulsifier. CONSTITUTION:The aqueous dispersion consisting of an aqueous dispersion of a copolymer which is obtained by emulsion polymerization of (A) a total of 100 pts.wt. of (1) 0.1-20wt.% of a hydroxyalkyl (meth)acrylate, (2) 40-99.8wt.% of an alkyl (meth)acrylate, (3) 0.1-10wt.% of an ethylenic unsaturated carboxylic acid such as (meth)acrylic acid and (4) 0-59.8wt.% of another copolymerizable ethylenic unsaturated monomer such as styrene in the presence of (B) 0.1-10 pts.wt. of a reactive emulsifier.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a coating suitable for coating the surface of a plastic substrate such as furniture, vinyl flooring, interior material for aircraft, interior / exterior material for motorcycles, automobiles, office equipment and the like. The present invention relates to an aqueous dispersion used for a vehicle.

[0002]

2. Description of the Related Art Conventionally, various solvent-type coating agents have been generally used for the purpose of protecting the surface of plastic base materials, rubber base materials, metal base materials, wood base materials, ceramic base materials and the like or maintaining their aesthetic appearance. Has been. However, solvent-based coating agents pose a number of problems such as occupational safety and health, health, and pollution due to the danger of fire and explosion, and their toxicity, and the shift to water-based coating agents is desired. There is.

Conventionally, in the case of a solvent type coating agent, the adhesion between the coating film obtained by applying the coating agent on the substrate and the substrate is such that the solvent contained in this coating agent is a plastic base material. While this was achieved by digging into the surface of materials, etc., in the case of water-based coating agents, such effects cannot be expected, so
The adhesion between the coating film and the substrate was not sufficient. Particularly in the case of a water-based coating agent, when a plastic substrate is used as the substrate, the adhesion between the coating film and the substrate was not sufficient.

[0004]

DISCLOSURE OF THE INVENTION The present invention is intended to solve the above-mentioned problems in the prior art, and solves the problem of work hygiene and improves the adhesion to the substrate. It is an object of the present invention to provide an aqueous dispersion for coating which is capable of forming a coating film which is excellent in hardness and antifouling property.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to solve the above problems, and found that the particle size was extremely small, and the reactive emulsifier was graft-bonded to the emulsion particles. The coating film formed from the copolymer water-dispersible resin emulsion that is strongly bonded has excellent adhesion to the substrate, especially the plastic substrate, and the coating film has excellent hardness and antifouling property. The present invention has been completed and the present invention has been completed.

That is, the aqueous dispersion for coating according to the present invention comprises (a) hydroxyalkyl (meth) acrylate 0.1 to 20% by weight, (b) alkyl (meth) acrylate 40 to 99.8% by weight, and c) 0.1 to 10% by weight of ethylenically unsaturated carboxylic acid, and (d) 0 to 59.8% by weight of other copolymerizable ethylenically unsaturated monomer.
And (a), ((a) + (b) +
(C) + (d) = 100% by weight),
It is characterized by comprising an aqueous dispersion of a copolymer obtained by emulsion polymerization in the presence of a total of 0.1 to 10 parts by weight with respect to parts by weight of the reactive emulsifier (b).

Hereinafter, each component of the aqueous dispersion for coating of the present invention will be described in detail. (A) Hydroxyalkyl (meth) acrylate (a) Hydroxyalkyl (meth) used in the present invention
Specific examples of the acrylate include hydroxymethyl (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate,
Examples thereof include hydroxybutyl (meth) acrylate, hydroxyamyl (meth) acrylate and hydroxyhexyl (meth) acrylate.

The hydroxyalkyl (meth) acrylate (a) is 0.1 to 20% by weight, preferably 0.5 to 15%, based on 100% by weight of the total of the monomer components.
%, More preferably 1 to 10% by weight.

When the amount of the hydroxyacryl (meth) acrylate is less than 0.1% by weight, the adhesiveness between the obtained coating film and the substrate is poor, and when it exceeds 20% by weight, the secondary adhesiveness is inferior. There is.

(B) Alkyl (meth) acrylate Specific examples of the (b) alkyl (meth) acrylate used in the present invention include methyl (meth) acrylate, ethyl (meth) acrylate, and propyl (meth) acrylate. , N-butyl (meth) acrylate, i-butyl (meth) acrylate, amyl (meth) acrylate,
i-amyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-
Examples include octyl (meth) acrylate. Of these, alkyl (meth) acrylates in which the alkyl group has 1 to 8 carbon atoms are preferable, and methyl (meth) acrylate is particularly preferable.
Acrylate, ethyl (meth) acrylate and butyl (meth) acrylate are preferred.

The (b) alkyl (meth) acrylate has a content of 4% when the total amount of the monomer components is 100% by weight.
It is used in an amount of 0 to 99.8% by weight, preferably 50 to 99% by weight, more preferably 60 to 98% by weight.

If the amount of the alkyl (meth) acrylate is less than 40% by weight, the resulting coating film may have poor antifouling property. (C) Ethylenically Unsaturated Carboxylic Acid Specific examples of the (c) ethylenically unsaturated carboxylic acid used in the present invention include (meth) acrylic acid, fumaric acid, itaconic acid, monoalkylitaconic acid, and maleic acid. Examples thereof include acids, crotonic acid, and α, β-unsaturated carboxylic acids such as 2- (meth) acryloyloxyethylhexahydrophthalic acid.

This (c) ethylenically unsaturated carboxylic acid has the following formula:
It is used in an amount of 0.1 to 10% by weight, preferably 0.5 to 8% by weight, more preferably 1 to 5% by weight.

When the amount of the ethylenically unsaturated carboxylic acid is less than 0.1% by weight, the secondary adhesion is poor, while 1
If it exceeds 0% by weight, the adhesion may be poor. (D) Other Copolymerizable Ethylenically Unsaturated Monomers Specific examples of the (d) other copolymerizable ethylenically unsaturated monomers used in the present invention include styrene and α.
-Methylstyrene, 4-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methoxystyrene, 2-hydroxymethylstyrene, 4-ethylstyrene, 4-ethoxystyrene, 3,4-dimethylstyrene, 2-chloro Styrene, 3-
Aromatic vinyl monomers such as chlorostyrene, 4-chloro-3-methylstyrene, 4-t-butylstyrene, 2,4-dichlorostyrene, 2,6-dichlorostyrene, 1-vinylnaphthalene and divinylbenzene, allyl Epoxy compounds such as glycidyl ether, glycidyl (meth) acrylate, methylglycidyl (meth) acrylate, divinylbenzene, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol Di (meth) acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, tetrapropylene glycol di (meth) acrylate, Polyfunctional monomers such as tandiol di (meth) acrylate, hexanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, (meth) acrylamide, N-methylol (meth) Acid amide compounds such as acrylamide, N-methoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, N, N'-methylenebisacrylamide, diacetone acrylamide, maleic acid amide, maleimide, vinyl chloride, vinylidene chloride, Vinyl compounds such as fatty acid vinyl esters, fluorine atom-containing monomers such as trifluoroethyl (meth) acrylate and pentadecafluorooctyl (meth) acrylate, γ- (meth) acryloylpropane trimethoxy Run, Chisso Co., Ltd. of SILAPLANE FM071
1 and other reactive silicones and other silicone compounds. Of these, styrene is particularly preferable.

The copolymerizable ethylenically unsaturated monomer (d) is 0 to 59.8% by weight, preferably 0 to 49% by weight, based on 100% by weight of the total of the monomer components.
More preferably, it is used in an amount of 0 to 38.0% by weight.

When the amount of the copolymerizable ethylenically unsaturated monomer (d) exceeds 59.8% by weight, a large amount of aggregates are generated during the polymerization, so that the resulting coating film is antifouling. It may be inferior.

(B) Reactive Emulsifier The aqueous dispersion for coating according to the present invention can be obtained by emulsion polymerization of the above monomer in the presence of the (b) reactive emulsifier. B) As a reactive emulsifier,
The particles having a polymerizable reactive group such as a vinyl group, an acrylic group, and a methacrylic group, and obtained by emulsion polymerization of the above-mentioned monomer in the presence of this reactive emulsifier have an average diameter of 20.
Those having a thickness of 0 nm or less are used.

The particularly preferable (b) reactive emulsifiers are shown below. (1) General formula 1

[0019]

[Chemical 1]

(In the formula, R ₁ is an alkylene group having 2 to 4 carbon atoms, R ₂ is a hydrocarbon group which may have a substituent, a phenyl group, an amino group or a carboxyl group, and R ₃
Is hydrogen or a methyl group, M is Na or NH ₄ , and p is an integer of 0 to 50. ) (2) General formula 2

[0021]

[Chemical 2]

(In the formula, R _{1 to} R ₃ , M and p are the same as in the general formula 1.) (3) General formula 3

[0023]

[Chemical 3]

(In the formula, R ₁ and R ₃ are the same as those in the general formula 1, R ₄ is a hydrocarbon group which may have a substituent, m is an integer of 0 to 100, and X is X. Is hydrogen, a nonionic hydrophilic group or an anionic hydrophilic group.) (4) General formula 4

[0025]

[Chemical 4]

(In the formula, R ₅ is an alkyl group, alkenyl group or aralkyl group having 4 to 18 carbon atoms, and R ₆ is hydrogen or an alkyl group, alkenyl group or aralkyl group having 4 to 18 carbon atoms. , R ₃ is hydrogen or a methyl group, and Y is —O— (R ₁ O) _q —H or —O.
_{- (R 1 O) q SO} 3 M (R 1 is an alkylene group or substituted alkylene group having 2 to 4 carbon atoms, M is an alkali metal atom, NH _4, or an alkanolamine residue, q is 2 to 2
00 is an integer), and n is an integer of 0 to 10. ) (5) General formula 5

[0027]

[Chemical 5]

(In the formula, R _{1 to} R ₃ and p are the same as in the general formula 1, and M is the same as in the general formula 4.) The reactive emulsifier having the above structural formula is anionic. Desirably, the use of such an anionic reactive emulsifier makes it possible to obtain an aqueous dispersion in which a copolymer having an average particle diameter of 200 nm or less is dispersed. Also,
Known anionic, nonionic and cationic emulsifiers may be used in combination as required.

This reactive emulsifier is 0.1 to 10 parts by weight, preferably 0.5 to 10 parts by weight, based on 100 parts by weight of the total amount of the monomers.
It is used in an amount of 10 parts by weight, more preferably 1.0 to 8 parts by weight.

If the amount of this reactive emulsifier is less than 0.1 parts by weight, the adhesion between the obtained coating film and the substrate may be poor, and if it exceeds 10 parts by weight, the secondary adhesion may be poor.

The aqueous dispersion for coating of the present invention can be obtained by emulsion-polymerizing the above-mentioned monomer (a) in the presence of a reactive emulsifier (b) under ordinary emulsion-polymerization conditions. For example, in the aqueous medium, the monomer component consisting of (a) to (d), the (b) reactive emulsifier, the polymerization initiator, the chain transfer agent, the chelating agent, the pH adjusting agent, etc. are added, It can be obtained by carrying out an emulsion polymerization reaction at a temperature of 30 to 100 ° C. for about 1 to 30 hours.

As the polymerization initiator, for example, water-soluble persulfate, hydrogen peroxide, etc. can be used, and in some cases, they can be used in combination with a reducing agent. Examples of the reducing agent include sodium pyrobisulfite, sodium hydrogen sulfite, sodium thiosulfate, L-ascorbic acid and salts thereof, sodium formaldehyde sulfoxylate and the like.

Further, an oil-soluble polymerization initiator such as 2,2'-
Azobisisobutyronitrile, 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis
-2,4-Dimethylvaleronitrile, 1,1'-azobis-cyclohexane-1-carbonitrile, benzoyl peroxide, dibutyl peroxide, cumene hydroperoxide, etc. may be dissolved in a monomer or solvent before use. it can.

These polymerization initiators are the total of the monomer components.
Used in an amount of 0.1 to 3 parts by weight per 100 parts by weight.
To be As a chain transfer agent, a halogenated hydrocarbon (
For example, chloroform, bromoform), mercaptan
Class (eg, n-dodecyl mercaptan, t-dodecyl meth
Lecaptan, n-octyl mercaptan), xanthogen
Class (for example, dimethylxanthogen disulfide,
Diisopropylxanthogen disulfide), terpe
(Eg, dipentene, terpinolene), α-
Methylstyrene dimer [2,4-diphenyl-4-methyl-1
-Penten (a₁), 2-4-diphenyl-4-methyl-pen
Ten (a₂), And 1-1-3-trimethyl-3-phenyl
Band (a ₃) At least one kind, preferably
(A₁) / (A₂) And / or (a₃) (Weight ratio)
= 40-100 / 0-60], unsaturated cyclic hydrocarbon compound
(For example, 9,10-dihydroanthracene, 1,4-dihi
Dronaphthalene, indene, 1,4-cyclohexadiene
Unsaturated heterocyclic compound (eg, xanthene
, 2,5-dihydrofuran) and the like.
The chain transfer agent is based on 100 parts by weight of the total of the monomer components,
Used in an amount of 0-5 parts by weight.

As the chelating agent, for example, glycine, alanine, ethylenediaminetetraacetic acid or the like is used, and as the pH adjusting agent, for example, sodium carbonate, potassium carbonate, sodium hydrogen carbonate, ammonia or the like is used. The chelating agent and the pH adjusting agent are each 0 to 100 parts by weight of the total of the monomer components.
It is used in an amount of about 0.1 part by weight, and 0 to 3 parts by weight.

The solvent used as necessary during the emulsion polymerization is a small amount of methyl ethyl ketone, acetone, trichlorotritriene, within the range that workability, disaster prevention safety, environmental safety and manufacturing safety are not impaired. Fluoroethane, methyl isobutyl ketone, dimethyl sulfoxide, toluene, dibutyl phthalate, methylpyrrolidone, ethyl acetate, alcohols, cellosolves, carbinols and the like are used. This organic solvent is about 0 to 5 parts by weight per 100 parts by weight of the total of the monomer components.

In the present invention, in order to produce an aqueous dispersion for coating by emulsion polymerization of the above-mentioned monomers, specifically, a known method, for example, the total amount of the above-mentioned monomer components is reacted. A method of charging all at once to the system, a method of charging a part of the monomer components and then reacting, and a method of charging the remaining monomer components continuously or dividedly, a method of continuously charging all the monomer components, etc. Can be done by

The glass transition temperature (Tg) of the copolymer present in the aqueous dispersion for coating of the present invention can be determined from the glass transition temperature of each component constituting the copolymer by the following formula.

[0039]

[Equation 1]

Tg: glass transition temperature of copolymer WA: weight fraction of component A WB: weight fraction of component TgA: glass transition temperature of component TgB: glass transition temperature of component B Water dispersion for coating The (meth) acrylic acid alkyl ester-based copolymer present in the body usually has a glass transition temperature of 0 ° C. or higher determined by this formula. When the glass transition temperature is less than 0 ° C, the hardness of the obtained coating film is poor, while when the glass transition temperature is 0 ° C or more, preferably 10 ° C or more, more preferably 20 ° C or more, the substrate, especially the plastic, is A coating film having excellent hardness and adhesiveness can be formed on a substrate. When the glass transition temperature is high, drying at room temperature may not form a uniform coating film. However, by adding a film-forming aid, high-temperature drying, or by using these means together, the surface of the substrate, particularly the plastic substrate surface It is possible to form a uniform coating film on top, and this coating film is also excellent in the adhesion performance with the substrate.

The average particle size of the copolymer in the aqueous dispersion for coating of the present invention is usually 200 nm or less, preferably 100 nm or less, more preferably 70 nm.
nm or less, and the average particle size of this copolymer is 200 n
If it exceeds m, the resulting coating film may have poor secondary adhesion.

A cross-linking agent may be added to the aqueous dispersion for coating of the present invention depending on the purpose. The amount of the crosslinking agent added is 100 parts by weight of the solid content of the aqueous dispersion,
Usually, it is 50 parts by weight or less, preferably 40 parts by weight or less.

As such a cross-linking agent, an amino resin,
Phenolic resin, epoxy resin, alkyd resin, thermosetting resin such as unsaturated polyester, isocyanate compound, blocked isocyanate compound, polyhydric alcohol,
Examples thereof include organic crosslinking agents such as aziridine compounds and oxazoline compounds, and inorganic crosslinking agents such as metals and metal compounds.

Specific examples of the amino resin include a completely alkyl type methylated melamine resin such as a hexamethoxymethylated melamine resin, a partially alkylated methylated melamine resin, a benzoguanamine resin and an alkyl etherified urea resin.

Examples of the isocyanate and the blocked isocyanate include tolylene diisocyanate and its hydrogenated product and its adduct, diphenylmethane diisocyanate and its hydrogenated product, triphenylmethane triisocyanate and its hydrogenated product, hexamethylene diisocyanate, xylylene diisocyanate and its Hydrogenated products, isophorone diisocyanate,
Examples thereof include dianisidine diisocyanate, tolidine diisocyanate, blocked polyisocyanate having an isocyanate group blocked, and any mixture thereof.

Specific examples of the phenol resin include dimethylol resin, polymethylolphenol resin, phenolformamide resin, methylolphenolformamide resin and dimethylolphenolformamide resin.

Specific examples of the epoxy resin include ethylene glycol diglycidyl ether, hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, glycerin diglycidyl ether, glycerin polyglycidyl ether, and diglycerin diglycidyl ether. Polyglycidyl ethers of polyhydric alcohols such as polyglycidyl ether, sorbitol polyglycidyl ether, hydrogenated bisphenol A diglycidyl ether, bisphenol A diglycidyl ether, p-
Examples thereof include oxybenzoic acid glycidyl ether, phthalic acid diglycidyl ester, hexahydrophthalic acid / diglycidyl ester, hydantoin ring-containing epoxy resin, and vinyl polymers having an epoxy group in the side chain.

Examples of the metal compound include oxides of metals such as zinc, zirconium, magnesium, copper, iron, cobalt, nickel, aluminum, cadmium and titanium or salts of these metals, carbonic acid, acetic acid, formic acid,
It is obtained by dissolving it in an acid such as glutaric acid, benzoic acid, or oxalic acid, or by adjusting the pH of the aqueous solution of these acids and a polyvalent metal compound to 7 to 11 with ammonia, amine, or the like. Those in the form of metal ions can also be included. The polyvalent metal compound is zinc ammonium carbonate, ammonium carbonate zirconate, zinc, zirconium oxide or salt. Those capable of forming a complex with the amine include morpholine,
Examples include monoethanolamine, ethylenediamine, diethylaminoethanol and the like. In addition, common complexing agents such as complexanes such as ethylenediaminetetraacetic acid, glycine and alanine can be used.

Specific examples of the aziridine compound include:
Tris-2,4,6- (1-aziridinyl) -1,3,5-triazine, tris [1- (2-methyl) -aziridinyl] phosphine oxide, hexa [1- (2-methyl) -aziridinyl]
Examples include triphosphatriazine.

As the oxazoline compound, specifically, a compound having an oxazoline ring in the molecule can be used. Specifically, a polymer crosslinking agent K manufactured by Nippon Shokubai Kagaku Co., Ltd. can be used.
-1000 series etc. are mentioned.

If necessary, a catalyst can be used, and examples thereof include amine-blocked acid catalysts such as dodecylbenzenesulfonic acid, p-toluenesulfonic acid and dinonylnaphthalenedisulfonic acid. This acid catalyst is preferably used in an amount of 0.05 to 2 parts by weight with respect to 100 parts by weight of the crosslinking agent to be added, which is calculated as the solid content.

As additives other than the above-mentioned additives,
Generally used water-soluble polyester resins, water-soluble or water-dispersible epoxy resins, water-soluble or water-dispersible acrylic resins, carboxylated aromatic vinyl resins such as styrene-maleic acid resins, urethane resins, metal oxides, A polyvalent metal salt, a lubricant, an antifoaming agent, a wetting agent, a leveling agent, a pigment and the like can be used.

Further, as additives, alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, amyl alcohol and hexyl alcohol, methyl cellosolve, ethyl cellosolve and propyl are added in order to improve film-forming property and wettability. Organic solvents such as cellosolve, butyl cellosolve, hexyl cellosolve, methyl carbitol, ethyl carbitol, methyl cellosolve acetate, ethyl cellosolve acetate, tributoxymethyl phosphate and the like can be used. This organic solvent is used in an amount of 20 parts by weight or less, preferably 10 parts by weight or less, based on 100 parts by weight of the solid content of the aqueous dispersion.

The aqueous dispersion for coating of the present invention has excellent adhesion to various base materials, particularly plastic base materials, and can form a coating film excellent in antifouling property and hardness. It is preferably used for surface coating of floor materials, aircraft interior materials, motorcycles, automobile interior / exterior materials, office equipment and the like.

The substrate to which the aqueous dispersion for coating of the present invention is applied includes plastics, rubbers, woods, ceramics and the like, but it is particularly preferable to apply it on a plastic substrate. For example, the coating of the present invention on a plastic substrate such as polyethylene, polypropylene, polystyrene, ABS resin, acrylic resin, polycarbonate, polyvinyl chloride, polyethylene terephthalate, preferably ABS resin, acrylic resin, polycarbonate, polyvinyl chloride, polyethylene terephthalate. When the aqueous dispersion is applied, a coating film having particularly excellent adhesion can be formed.

[0056]

EXAMPLES The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples as long as the gist thereof is not exceeded.

In the examples, parts and percentages indicating ratios are given.
Is on a weight basis. Further, the measurement of various physical properties in Examples was based on the following methods. Adhesion According to JIS K5400, a 1 mm square 100 cross-cut test was performed, and the peeled state was confirmed with cellophane tape.
It was indicated by the number of adhesions in 0 pieces. Secondary Adhesion Adhesion was measured on a test piece that had been immersed in deionized water for 24 hours and then dried at room temperature for 2 hours. Pencil hardness According to JIS K5400, it was measured using a pencil scratch tester. Those having a hardness of 4B or less were judged to have not achieved the object of the present invention. A mixture of antifouling carbon black and glycerin was applied to a test piece, allowed to stand for 24 hours and then washed with water, and the condition of dirt was observed. The one with severe dirt was marked with X, and the one with no change was marked with ◯. The average particle diameter of the particle size emulsion polymerization to obtained aqueous dispersion of the water dispersion was measured using Oba Electronic Co., Ltd. laser particle size analyzer LPA-3000.

[0058]

Example 1 A stainless steel autoclave equipped with a stirrer, a thermometer and a monomer addition pump was equipped with a heater and a nitrogen gas introducing device, and water was added to the autoclave.
0 parts, 3 parts of AQUALON RN-20 manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd. (an example of the reactive emulsifier represented by the general formula (4) in the text) and 0.3 parts of sodium persulfate were charged, and the gas phase part was 1
The atmosphere was replaced with nitrogen gas for 5 minutes, and the temperature was raised to 75 ° C.

Then, from a separate container, ethyl acrylate 4
0 parts, n-butyl acrylate 10 parts, methyl methacrylate 44 parts, hydroxyethyl methacrylate 5
Parts, 1 part of methacrylic acid, and an emulsion consisting of 2 parts of alkylallyl sulfosuccinate and 40 parts of water were continuously added over 3 hours. After the addition was completed, the mixture was further aged at 85 to 95 ° C. for 2 hours, cooled to 25 ° C., adjusted to pH 8 with ammonia water, adjusted to a solid content concentration of 40% with water, and then filtered through a 200 mesh wire mesh. , An aqueous dispersion was obtained.

The thus-obtained water dispersion had a particle size of 50 nm and a Tg of 22 ° C. ABS obtained by previously wiping the surface of the obtained aqueous dispersion with methanol
A resin plate was dried and applied with a bar coater to a film thickness of 10 μm, and dried in an atmosphere of 80 ° C. for 30 minutes to prepare a test piece.

The adhesiveness, secondary adhesiveness and pencil hardness of the obtained test piece were measured. The results are shown in Table 1.

[0062]

Example 2 A test piece was prepared and evaluated in the same manner as in Example 1 except that the kinds of monomers and the charged amount were changed as shown in Table 1.

The results are shown in Table 1.

[0064]

Example 3 In Example 1, the kinds of monomers and the charged amount were changed as shown in Table 1, and the obtained aqueous dispersion was added with 20 parts by weight of a 50% aqueous solution of ethylcarbitol and Nippon Shokubai. Test pieces were prepared and evaluated in the same manner as in Example 1 except that 10 parts by weight of K1020E manufactured by Kagaku Co., Ltd. was added.

The results are shown in Table 1.

[0066]

[Comparative Examples 1 and 2] Test pieces were prepared in the same manner as in Example 1 except that the kinds of monomers and the charged amount were changed as shown in Table 1 and the same as in Example 1. And evaluated.

The results are shown in Table 1. From the results in Table 1,
(A) Hydroxyalkyl (meth) acrylate is 0.
It can be seen that if it is less than 1% by weight, the adhesion is poor, and if it exceeds 20 parts, the secondary adhesion is poor.

[0068]

Comparative Example 3 An aqueous dispersion and a test piece were prepared in the same manner as in Example 1 except that the kinds of monomers and the charged amount were changed as shown in Table 1. It evaluated similarly to.

The results are shown in Table 1.

[0070]

[Comparative Example 4] An aqueous dispersion and a test piece were prepared in the same manner as in Example 3 except that the kinds of monomers and the charged amount were changed as shown in Table 1. It evaluated similarly to.

The results are shown in Table 1. From the results in Table 1,
It can be seen that when (c) the ethylenically unsaturated carboxylic acid is less than 0.1% by weight, the secondary adhesiveness and antifouling property are inferior, while when it exceeds 10% by weight, the adhesiveness is inferior.

[0072]

COMPARATIVE EXAMPLE 5 A test piece was prepared and evaluated in the same manner as in Example 2 except that the type of monomer and the charged amount were changed as shown in Table 1.

The results are shown in Table 1. From the results in Table 1,
It can be seen that if the total amount of the (b) alkyl (meth) acrylate is less than 40% by weight, the antifouling property is poor.

[0074]

Comparative Example 6 Example 1 was repeated except that the charged amount of (b) reactive emulsifier was changed as shown in Table 1.
An aqueous dispersion and a test piece were prepared in the same manner as in Example 1, and Example 1
It evaluated similarly to.

The results are shown in Table 1. From the results in Table 1,
(B) When the reactive emulsifier exceeds 10 parts by weight, the secondary adhesion is inferior.

[0076]

Comparative Example 7 An aqueous dispersion and a test piece were prepared in the same manner as in Example 1 except that sodium dodecylbenzenesulfonate was used instead of the (b) reactive emulsifier in Example 1. Evaluation was carried out in the same manner as in Example 1.

The results are shown in Table 1. From the results in Table 1, it can be seen that the adhesion is inferior when an ordinary emulsifier is used.

[0078]

Comparative Example 8 An aqueous dispersion and a test piece were prepared in the same manner as in Example 1 except that the kinds of monomers and the charged amount were changed as shown in Table 1. It evaluated similarly to.

The results are shown in Table 1. From the results in Table 1, it is understood that when the Tg of the copolymer in the aqueous dispersion is less than 0 ° C, the hardness and the adhesiveness are poor.

[0080]

Comparative Example 9 An aqueous dispersion and a test piece were prepared in the same manner as in Example 1 except that the amount of the reactive emulsifier charged was changed as shown in Table 1. And evaluated.

The results are shown in Table 1. From the results in Table 1, it can be seen that when the average particle diameter of the water dispersion exceeds 200 nm, the adhesion is poor.

[0082]

[Table 1]

[0083]

[Table 2]

[0084]

EFFECT OF THE INVENTION The aqueous dispersion for coating of the present invention has excellent adhesion to a substrate and can form a coating film excellent in antifouling property and hardness.
It can be used for surface coating of various base materials such as furniture, vinyl flooring materials, interior materials for aircraft, motorcycles, interior / exterior materials for automobiles, and office equipment.

Claims (2)

[Claims] 1. (a) Hydroxyalkyl (meth) acrylate 0.1 to 20% by weight (b) Alkyl (meth) acrylate 40 to 99.8% by weight (c) Ethylenically unsaturated carboxylic acid 0.1 to 10 % By weight (d) Other copolymerizable ethylenically unsaturated monomer 0 to
59.8% by weight of monomer (a), (provided that (a) + (b) +
(C) + (d) = 100% by weight), when the total amount of the above monomer components is 100 parts by weight,
An aqueous dispersion for coating, comprising an aqueous dispersion of a copolymer obtained by emulsion polymerization in the presence of a reactive emulsifier (b) in an amount of 1 to 10 parts by weight. 2. The water dispersion according to claim 1, which is used for coating a plastic substrate.