JPH0578600A - Water-base coating composition and coating method using the same - Google Patents

Abstract

PURPOSE:To obtain the subject composition which is free from sag and metal unevenness, gives a film having excellent smoothness and water resistance and is preferable from the viewpoint of pollution control by incorporating, as an essential base resin component, a water-base dispersion of fine polymer particles obtained from a specific monomer. CONSTITUTION:The objective composition comprises, as an essential base resin component, a water-base dispersion of fine polymer particles obtained from an ethylenically unsaturated monomer having a 2-oxo-1,3-dioxolan-4-yl group represented by the formula (wherein R<1> to R<3> are each H or a 1-4C alkyl), e.g., 2,3-carbonatopropyl methacrylate.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel and useful aqueous coating composition and a coating method using the same. More specifically, 2-oxo-1,3-dioxolane-4-
It comprises, as an essential base resin component, an aqueous product of a fine particle polymer obtained by using an ethylenically unsaturated monomer having a specific group called an yl group. Particularly, it is newly useful from the viewpoint of preventing environmental pollution. And a coating method using the same.

[0002]

2. Description of the Related Art From the viewpoint of global environmental problems, reduction of organic solvent emissions into the atmosphere is urgently desired. Even in the paint industry, attempts are currently being made to reduce the amount of organic solvents used.

In particular, automobile paints have a serious problem that a large amount of organic solvents are currently discharged into the atmosphere from the fact that automobiles are currently produced in large quantities and pollute the environment. Of course, this is a problem that must be resolved immediately, and it is never something that can be neglected.

[0004]

As described above, the conventional solvent-based paint has a serious problem that the environment is polluted by the discharged organic solvent, and steadily prevents the paint from becoming water-based. Consideration is coming.

However, since the evaporation rate of water is slower than that of the organic solvents that have been used so far, it takes time to change the applied coating film to an appropriate flow property after coating. Therefore, for example, problems such as sagging and, in the case of metallic bases, problems such as defective orientation of aluminum powder will occur.

[0006] Conventionally, attempts have been made to add a thickening agent in the form of a protective colloid to adjust the flow properties of water-based paints, but the effect was not satisfactory. Further, the combination of crosslinked polymer particles and a steric stabilizer having a hydrophilic portion for stabilizing the crosslinked polymer particles has been studied, and although the effect is recognized, it is still insufficient. .

[0007]

Therefore, the present inventors have
Focusing on the problem to be solved as described above, as a result of intensive studies, three-dimensional internal crosslinked specific fine particles, and a polymer for stabilizing it, by a specific means. It has been found that a coating film having an excellent finished appearance can be formed by using an aqueous coating composition obtained by chemically bonding, and the present invention has been completed here.

That is, according to the present invention, as an essential component, 2
An oxo-1,3-dioxolan-4-yl group-containing ethylenically unsaturated monomer-containing hydrate of a fine particle polymer, or an hydrate of the fine particle polymer, It is intended to provide a specific aqueous coating composition comprising a curing agent, or an aqueous product of the particulate polymer, a curing agent, and a curing catalyst, and further, It is intended to provide a coating method (coating film forming method), which comprises using a specific water-based coating composition.

Here, the aqueous coating composition used in the present invention is obtained, for example, by the following steps. (1) First, the first step is

[0010]

[Chemical 5]

[However, in the formula, R ¹ , R ² and R ³
Are each a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, which may be the same or different. ] And an ethylenically unsaturated monomer (A) having a 2-oxo-1,3-dioxolan-4-yl group and another copolymerizable ethylenically unsaturated monomer (B) That is, a so-called emulsion (emulsion) in a form in which a fine particle polymer obtained by polymerization in an aqueous medium is dispersed in water is prepared.

Next, by using the fine particle polymer (1) obtained in the above step as a core portion, an internal cross-linking method of this core portion and a shell portion for chemically stabilizing the particles are chemically bonded. I will describe the method and. (2) Two or more 1's in one molecule in the polymer (1)
By adding a compound (C) having a secondary and / or secondary amino group, and present in the fine particle polymer (1) is a 2-oxo-1,3-dioxolan-4-yl group (hereinafter, also referred to as a cyclocarbonate group). Internal cross-linking is carried out by reacting with 1 part of the above.

On the other hand, by reacting the remaining cyclocarbonate group with the ethylenically unsaturated monomer (D) having a primary and / or secondary amino group, the surface of the particulate polymer is polymerizable unsaturated. A group can be introduced, and by using allyl (meth) acrylate (E), the unsaturated group of the (meth) acryloyl moiety mainly remains unreacted in the particulate polymer. Copolymerize with the polymerizable unsaturated group, and as a result, the unsaturated group in the allyl moiety is likely to remain unreacted, and the polymerizable unsaturated group is introduced and concentrated on the surface of the particulate polymer. It becomes a place.

In this way, a step of introducing a bonding point for chemically bonding with the shell portion and then polymerizing the shell portion is continued. (3) The reaction product (2) thus obtained, that is, internal cross-linking proceeds, and a polymerizable unsaturated group, which is a bonding point for chemically bonding with the shell part, is introduced on the surface. The reaction product (2) in the form of (1) is polymerized with a carboxyl group-containing ethylenically unsaturated monomer (F) and another copolymerizable ethylenically unsaturated monomer (G). Neutralize the group to form the shell part,
At this point, the desired aqueous coating composition having a core / shell structure can be prepared.

The structure of the present invention will be described in more detail below. First, the particulate polymer (1) of the present invention
The preparation method of is described. The ethylenically unsaturated monomer (A) having a 2-oxo-1,3-dioxolan-4-yl group (cyclocarbonate group) represented by the above general formula [I] is, for example,

[0016]

[Chemical 6]

[Wherein R ¹ , R ² and R ³ in the formula are as defined above, R ⁴ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and n
Is an integer of 1 to 6. ] And the like.

Specifically, 2,3-carbonate propyl (meth) acrylate, 3,4-carbonate butyl (meth) acrylate, 4,5-carbonate pentyl (meth) acrylate and 6,7-carbonate hexyl (meth) Acrylate, 2,3-carbonate propyl vinyl ether, methyl-2,3-carbonate propyl crotonate and the like are particularly representative.

The amount of these monomers (A) used is as follows:
Appropriately within the range of 0.1 to 80 parts by weight, preferably 0.5 to 50 parts by weight. If it is less than 0.1 part by weight, the effect cannot be realized, and if it exceeds 80 parts by weight, dispersion stability is inevitable during the subsequent addition reaction with the carboxyl group-containing ethylenically unsaturated monomer. The property deteriorates, and as a result, spots are formed and gelation occurs.

Further, only the particularly representative examples of the monomer (B) having at least two ethylenically unsaturated groups in the above-mentioned molecule will be mentioned, ethylene glycol di (meth) acrylate, Triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, 1,4-butanediol di (meth) acrylate , Neopentyl glycol di (meta)
Acrylate, 1,6-hexanediol di (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, glycerol di (meth) acrylate, 1,1,1
-Trishydroxymethylpropane di (meth) acrylate, 1,1,1-trishydroxymethylpropane tri (meth) acrylate, triallyl cyanurate, diallyl terephthalate, diallyl phthalate, allyl (meth) acrylate or divinylbenzene, and the like, Furthermore, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4
Various hydroxyalkyl (meth) acrylates, such as -hydrodibutyl (meth) acrylate; 2
-Various hydroxyalkyl vinyl ethers such as hydroxyethyl vinyl ether and 4-hydroxybutyl vinyl ether; or various allyl compounds such as allyl alcohol or hydroxyethyl allyl ether; , Ε-caprolactone-added hydroxyl group-containing unsaturated monomers;
Examples thereof include adducts with maleic anhydride or itaconic anhydride, and alkyl esters of these adducts.

Next, as described above, other copolymerizable ethylenic compounds except the various cyclocarbonate group-containing ethylenically unsaturated monomers (A) and various monomers (B) are removed, respectively. Unsaturated monomer (C), ie, another ethylenically unsaturated monomer (C) copolymerizable with monomer (A) and monomer (B), respectively, as listed above. Examples of the α, β-unsaturated mono-carboxylic acid such as (meth) acrylic acid, maleic acid, fumaric acid or itaconic acid are listed as only typical ones.
Or dicarboxylic acids; or various α, β-ethylenically unsaturated dicarboxylic acids such as monoethyl maleate, monobutyl maleate, monobutyl fumarate or monoethyl itaconate, and a monovalent alcohol having 1 to 4 carbon atoms. S-compound; or carboxyl group-containing unsaturated form obtained by adding various acid anhydrides such as phthalic anhydride to various hydroxyl group-containing vinyl monomers such as 2-hydroxyethyl (meth) acrylate Monomers;

2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3
Various hydroxyalkyl (meth) acrylates such as -hydroxypropyl (meth) acrylate and 4-hydrodibutyl (meth) acrylate; various hydroxyalkyl vinyl ethers such as 2-hydroxyethyl vinyl ether and 4-hydroxybutyl vinyl ether; or Various allyl compounds such as allyl alcohol or hydroxyethyl allyl ether; or hydroxyl group-containing unsaturated monomers obtained by adding ε-caprolactone to the above monomers;

Various types of alkyl (meth) acrylates having an alkyl group having 1 to 22 carbon atoms, 2-ethoxyethyl (meth) acrylate, cyclohexyl (meth) acrylate or (meth) acrylonitrile, containing no reactive polar group. (Meth) acrylates; various epoxy group-containing (meth) acrylates such as glycidyl (meth) acrylate and methylglycidyl (meth) acrylate; various kinds of (meth) acrylamide or N-alkoxymethylated (meth) acrylamide Starting with basic nitrogen atom-containing compounds,

Various reactive polar group-containing (meth) acrylates such as phosphoric acid group-containing (meth) acrylates or hydrolyzable silyl group-containing (meth) acrylates;
Various aromatic vinyl monomers such as styrene, tert-butylstyrene, α-methylstyrene or vinyltoluene; or vinyl fluoride, tetrafluoroethylene or hexafluoropropylene,
Examples include various fluorine-containing vinyl monomers.

To prepare the fine particle polymer (1), a conventional method such as an emulsion polymerization method or a dispersion polymerization method may be used. As only emulsifying agents or dispersion stabilizers used here, only representative ones include organic sulfonate-based or organic sulfate-based anionic surfactants, among which,
So-called reactive emulsifiers having an ethylenically unsaturated group are also included.

Further, various dispersion stabilizers such as organic carboxylic acid salt type, polyvinyl alcohol type, cellulose type and pyrrolidone type are applied. Organic sulfonate surfactants include ester sulfonates, amide sulfonates, ether sulfonates, alkylallyl sulfonates, among which dioctyl sulfosuccinic acid and dodecyl benzene sulfonate. Included are amine salts or sodium or potassium salts of acids.

Examples of the organic sulfate-based surfactants include higher alcohol sulfate ester salts, polyethylene glycol ether sulfate ester salts, amide sulfate ester salts, and the like. Among them, amine salts of lauryl sulfate or sodium or potassium salts, Examples thereof include amine salts of alkylallyl polyether sulfate or sodium or potassium salts.

Examples of the reactive emulsifier include styrene sulfonate, "Eleminol JS-2" [product of Sanyo Kasei Co., Ltd.] or "Aqualon RN-20" [product of Dai-ichi Kogyo Seiyaku Co., Ltd.] and the like.

Examples of nonionic emulsifiers include polyethylene glycol alkylphenyl ethers, and examples of such nonionic reactive emulsifiers include polyethylene glycol (meth) whose one end is an alkyl ether.
There are acryloyl oxyethers.

As the polymerization initiator used for emulsion polymerization, organic peroxides, azo polymerization initiators, redox polymerization initiators and the like are particularly representative. As the organic peroxides, only typical ones are exemplified by benzoyl peroxide, tert-butyl hydroperoxide, ditert-butyl peroxide, and the like, and only typical inorganic peroxides are mentioned. If it is limited to-, ammonium salts, -sodium salts or potassium salts of persulfate, hydrogen peroxide, etc., and if only representative examples of azo-based initiators are listed, 4, 4 '-Azobis (4-cyanovaleric acid) and the like, and only specific examples of redox polymerization initiators are listed: hydrogen peroxide-ferrous salt, persulfate-sodium acid sulfite, Cumene hydroperoxide-N, N-dimethylaniline, etc., but the emulsion polymerization in the present invention is not particularly limited depending on the kind of the initiator. Not to receive.

Further, if necessary, various chain transfer agents such as lauryl mercaptan, octyl mercaptan, 2-mercaptoethanol, octyl thioglycolate, 3-mercaptopropionic acid or α-methylstyrene dimer may be used as a molecular weight modifier. it can.

The compound (D-1) having two or more primary and / or secondary amino groups in one molecule to be reacted with the fine particle polymer (1) thus obtained is an aliphatic polyamine or aromatic compound. At least one selected from various known and commonly used polyamines such as polyamine, complex polyamine, modified aliphatic polyamine or heterocyclic polyamine can be appropriately selected.

Specific examples thereof include ethylenediamine,
1,2-diaminopropane, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, 1, -8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,2-diaminocyclohexanone, 1,4-bis (3-aminopropyl) piperazine, 3,9-bis (3-aminopropyl)
-2,4,8,10-tetraoxaspiro [5,5] undecane, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, N, N'-bis (2-aminomethyl) ethylenediamine, N, N'-bis (2-aminoethyl) -ethylenediamine, N, N'-bis (3-aminopropyl)
Ethylenediamine, N, N'-bis (2-aminomethyl) -1,3-propanediamine, N, N'-bis (2
-Aminomethyl) -1,4-butanediamine, N, N '
-Bis (2-aminoethyl) -1,4-butanediamine, N, N'-bis (2-aminopropyl) -1,4-
Butanediamine, bis (4-aminocyclohexyl) methane, 1,3-bis (aminomethyl) cyclohexane or "Jeffamine D-230 or D-40.
0 "[Mitsui Texaco Chemical Co., Ltd. product], such as various bifunctional primary amine compounds;

Alternatively, trisaminoethylamine, 4
Various trifunctional primary polyamine compounds such as -aminomethyl-1,8-diaminooctane or "Jeffamine T-403" (manufactured by the same company);

Further, acid group-containing acrylic resin-propyleneimine adduct; epoxy resin-diethylenetriamine adduct; amine-ethylene oxide adduct or oligoester (meth) acrylate adduct with various polyamines such as those mentioned above. It is particularly representative.

The amount of the polyamine compound (D-1) to be used is appropriately in the range of an equivalent ratio of amino group / cyclocarbonate group of 0.01 to 0.5. 0.0
If it is less than 1, the internal crosslinking effect is insufficient. On the other hand, if it is more than 0.5, interparticle crosslinking is apt to occur, which is not preferable.

On the other hand, the ethylenically unsaturated monomer (D-2) having a primary and / or secondary amino group to be reacted with the fine particle polymer (1) has at least one 1 in one molecule. Any compound having both a primary or secondary amino group and an ethylenically unsaturated group may be used. Of these, only typical ones are allylamine, N-methylallylamine, diallylamine or 2- (1-cyclohexenyl) ethylamine and the like.

The amount of the monomer (D-2) used is such that the equivalent ratio of amino group / cyclocarbonate group is 0.
The range of 01 to 0.5 is suitable. If it is less than 0.01, the effect due to the binding between the core portion and the shell portion cannot be sufficiently exhibited, while if it exceeds 0.5, the viscosity is remarkably increased when the shell portion is polymerized. In addition, it is not preferable in any case, because it becomes easy to generate a lump or a lump, and depending on the case, it becomes gelatinized.

Further, the amount of allyl (meth) acrylate (E) used to react with the polymer (1) is
The amount is 25 parts or less, preferably 10 parts or less, relative to 100 parts of the polymer solid.

The carboxyl group-containing ethylenically unsaturated monomer (F) to be copolymerized with the ethylenically unsaturated group introduced on the surface of the reaction product (2) thus obtained
Are various ethylenically unsaturated mono- or dicarboxylic acids such as (meth) acrylic acid, maleic acid, fumaric acid or itaconic acid; or monoethyl maleate, monobutyl maleate, monobutyl fumarate or monoethyl itaconate. , An ester compound of various ethylenically unsaturated dicarboxylic acids and a monohydric alcohol having 1 to 4 carbon atoms; or a form obtained by addition-reacting various acid anhydrides with 2-hydroxyethyl (meth) acrylate Of these, various carboxyl group-containing unsaturated monomers and the like are particularly representative.

Next, other copolymerizable ethylenically unsaturated monomers (G) other than the above-mentioned carboxyl group-containing ethylenically unsaturated monomers (F), which can be copolymerized, are mentioned above. As described above, at least one selected from various monomers (C) may be used.

The compound for neutralizing the carboxyl group after polymerization may be a basic substance, and of these, only typical ones will be mentioned.
Various amine compounds such as ammonia, triethylamine, N, N-dimethylethanolamine and N-methylmorpholine; or various metal hydroxides such as sodium hydroxide and potassium hydroxide.

The aqueous composition thus obtained is optionally combined with a known and commonly used curing agent such as a blocked polyisocyanate and / or a melamine resin to obtain a carboxyl group and / or a carboxyl group in the aqueous composition.
Alternatively, a cured coating film can be obtained by reacting with a hydroxyl group and curing, and by blending a compound having at least two primary and / or secondary amino groups in one molecule as such a curing agent, By reacting with the remaining cyclocarbonate group and curing, a cured coating film can be obtained, and further, by mixing a quaternary ammonium salt as a curing catalyst, the reaction between the remaining cyclocarbonate group and the carboxyl group Alternatively, it can be cured through self-condensation of cyclocarbonate groups.

Here, as the compound having at least two primary and / or secondary amino groups in one molecule, various compounds (D-1) as described above can be used, and on the other hand, The quaternary ammonium salt has a quaternary ammonium hydroxide represented by tetramethylammonium hydroxide or trimethylbenzylammonium hydroxide; or a carboxylate anion represented by tetramethylammonium propionate as a counter ion. Particularly, typical ammonium salts are typical.

Alternatively, the aqueous composition may further contain various thickeners such as polycarboxylic acid type, polyethylene glycol type, cellulose type, polyvinyl alcohol type, polyvinylpyrrolidone type; calcium carbonate; , Various inorganic fillers; bentonite-based thixotropic agents, various powders such as aluminum powder, various metal powders, organic pigments or inorganic pigments, or
Various organic fillers such as an ultraviolet absorber, an antioxidant, a pigment dispersant or a leveling agent can be blended.

If necessary, methanol,
It is also possible to add various conventionally known organic solvents such as ethanol, isopropanol, n-butanol, ethylene glycol monomethyl ether, cellosolve acetate, acetone, methyl ethyl ketone, methyl isobutyl ketone, N-methylpyrrolidone, toluene or xylene. Of course.

Thus, the aqueous coating composition of the present invention comprises PC
It can be used for general baking such as for M and home appliances, for exterior of buildings and roof tiles, or for automobiles.

In particular, in the case of automobiles, the water-based paint thus obtained is used as a base coat for forming a coating film by a two-coat two-bake system, a two-coat one-bake system or an overcoat system. , A color pigment and / or a metallic pigment can be used in a mixed form.

The baking condition depends on the type of clear paint used in the above-mentioned coating method.
Generally, it may be about 15 to 30 minutes within a range of 80 to 160 ° C.

As the clear paint used here,
Any material may be used as long as it can be used as a top clear paint for automobiles, and examples thereof include a paint containing a hydroxyl group-containing resin and a melamine resin, and a paint containing a hydroxyl group-containing resin and a polyisocyanate. However, of course, it is not limited to these.

[0051]

EXAMPLES Next, the present invention will be described more specifically with reference to Reference Examples, Examples and Comparative Examples.
It is not limited to these examples.

Unless otherwise specified below,
All parts and percentages are by weight. Reference Example 1 (Preparation Example of Aqueous Product of Fine Particle Polymer) 1,300 parts of deionized water was put in a flask equipped with a dropping device, a stirrer, a thermometer, a cooling pipe and a nitrogen gas introducing pipe. While heating to 75 to 85 ° C. and stirring under a nitrogen atmosphere, 100 parts of 2,3-carbonate propyl methacrylate, 200 parts of methyl methacrylate,
200 parts of styrene, 44 of n-butyl methacrylate
0 part, neopentyl glycol dimethacrylate 40
And 20 parts of methacrylic acid and 2 parts of polyoxyethylene nonylphenyl ether sulfate sodium salt
0 part and 5 parts of sodium persulfate and 2 parts of deionized water
100 parts of a mixture consisting of 00 parts was added dropwise and kept under the same conditions for 30 minutes, and the remaining mixture was added dropwise over 3 hours. After the dropping was completed, the same conditions were maintained for 1 hour.

Next, 20 parts of allylamine was added, and the mixture was kept under the same conditions for 30 minutes to react the cyclocarbonate group with the amino group. After that, 800 of deionized water
40 parts of acrylic acid, 20 parts of 2-hydroxypropyl methacrylate, 55 parts of methyl methacrylate and 35 parts of n-butyl acrylate, 5 parts of polyoxyethylene nonylphenyl ether sulfate sodium salt and sodium persulfate. A mixture of 2 parts and 5 parts of deionized water was added dropwise over 1 hour.

Next, the temperature was maintained for 1 hour and then cooled to room temperature, and deionized water was added so that the solid content was 30%. The polymer particles thus obtained were insoluble in organic solvents.

After that, deionized water was added, and the mixture was neutralized with dimethylethanolamine and adjusted to a solid content of 20% to obtain an aqueous solution of a target fine particle polymer having a core / shell structure. Got Hereafter, this is MP-
Abbreviated as 1.

Reference Example 2 (Same as above) 1,300 parts of deionized water was placed in a flask equipped with a dropping device, a stirrer, a thermometer, a cooling pipe and a nitrogen gas introducing pipe and heated to 75 to 85 ° C. While stirring under a nitrogen atmosphere, 200 parts of 2,3-carbonate propyl methacrylate, 100 parts of methyl methacrylate, 480 parts of n-butyl methacrylate, 190 parts of n-butyl acrylate, 10 parts of neopentyl glycol dimethacrylate. And 20 parts of methacrylic acid, 20 parts of polyoxyethylene nonylphenyl ether sulfate sodium salt and 5 parts of sodium persulfate, and 100 parts of a mixture of 200 parts of deionized water,
After maintaining the same conditions for 30 minutes, the remaining mixture was added dropwise over 3 hours. After the dropping was completed, the same conditions were maintained for 1 hour.

Then, 20 parts of allyl methacrylate was added and kept under the same conditions for 30 minutes, and then 10 parts of allylamine was added and kept under the same conditions for 30 minutes. Then 800 parts of deionized water and 40 parts of acrylic acid
Part, 20 parts of 2-hydroxypropyl methacrylate,
Mix a mixture of 55 parts of methyl methacrylate and 35 parts of n-butyl acrylate, 5 parts of sodium polyoxyethylene nonylphenyl ether sulfate and 2 parts of sodium persulfate, and 5 parts of deionized water for 1 hour. It dripped over.

Next, the temperature was maintained at the same temperature for 1 hour and then cooled to room temperature, and deionized water was added so that the solid content was 30%. The polymer particles thus obtained were insoluble in organic solvents.

After that, deionized water was added, and the mixture was neutralized with dimethylethanolamine and adjusted to a solid content of 20% to obtain an aqueous solution of a target fine particle polymer having a core / shell structure. Got Hereafter, this is MP-
It is abbreviated as 2.

Reference Example 3 (Method for producing comparative resin) 1,300 parts of deionized water was placed in a flask equipped with a dropping device, a stirrer, a thermometer, a cooling pipe and a nitrogen gas introducing pipe, and the mixture was heated to 75- While heating to 85 ° C. and stirring under a nitrogen atmosphere, 200 parts of styrene, 100 parts of methyl methacrylate, 500 parts of n-butyl methacrylate, n-butyl methacrylate
100 parts of a mixture consisting of 170 parts of butyl acrylate and 30 parts of neopentyl glycol dimethacrylate, 20 parts of polyoxyethylene nonylphenyl ether sulfate sodium salt and 5 parts of sodium persulfate and 200 parts of deionized water. Was added dropwise and kept under the same conditions for 30 minutes, and then the remaining mixture was added dropwise over 3 hours.

After the completion of dropping, the emulsion was kept under the same conditions for 30 minutes to obtain an emulsion of the non-internally crosslinked polymer for use. Hereinafter, this is abbreviated as P-1. Examples 1 to 6 and Comparative Example 1 Using the respective resins obtained in Reference Examples 1 to 3,
Various water-based paints were obtained according to the composition ratios (numerical values indicate parts by weight) as shown in the table.

Further, the water-based paint thus obtained was used as a base coat, and the performance of various coating films obtained by 2 coat 2 bake or 2 coat 1 bake or overcoat finish was evaluated. It was The results are also shown in the same table.

[0063]

[Table 1]

<Explanation of Table Annotations> a) C-325 ............... "Cyanamid C-32
5 "[methyl etherified melamine resin manufactured by Mitsui Cyanamid Co., Ltd.] b) L-127-75B ..." Super Beckamine L-
127-75B "[Butyl etherified melamine resin manufactured by Dainippon Ink and Chemicals, Inc.] c) B7-887-60 ..." Bernock B7-887 "
-60 "[block polyisocyanate manufactured by Dainippon Ink and Chemicals, Inc.] d) ASE-60 ..." Acrysol ASE-6
0 ”(polycarboxylic acid type thickener manufactured by Rohm and Haas Co.) with deionized water added thereto and neutralized with dimethylethanolamine to have a resin solid content of 3% e) Type of clear coating film : 1. Acrylic melamine paint ... "Acridic A-3
10 "[hydroxyl group-containing acrylic resin manufactured by Dainippon Ink and Chemicals, Inc./"Super Beckamine L-117-6"
0 "(butyl etherified melamine resin manufactured by the same company) = 7
1. A paint having a composition of 0/30 (solid content ratio) and containing 50 ppm of "LO-50" (a silicon-based leveling agent manufactured by Wacker Chemical Co.) based on the resin solid content. Two-component acrylic urethane paint ... "Acridic
BU-955 "[a hydroxyl group-containing acrylic resin manufactured by Dainippon Ink and Chemicals, Inc .; nonvolatile content = 60%, hydroxyl value =
44 ± 3] and “Bernock DN-980” [polyisocyanate manufactured by Dainippon Ink and Chemicals, Inc .; nonvolatile content = 75%, NCO% = 15 to 16%], OH /
2. A paint which is blended so that NCO = 1 (equivalent ratio) and which contains 50 ppm of "LO-50" based on the resin solid content. Powder paint ………… “Findick A-207
S ”[a glycidyl group-containing acrylic resin manufactured by Dainippon Ink and Chemicals, Inc.] / Decanedioic acid = 85/15 (weight ratio of solid content), which is based on the resin solid content. Paint containing 1% of "Modaflow" (leveling agent manufactured by Monsanto Co., Ltd.) f) Type of finishing method: 1.2C1B .... Baking is 140C for 20 minutes 2.2C2B .... Baking 3) Caking for 30 minutes at 80 ° C. 3.2C2B ... Baking for 140 minutes at 140 ° C for the base coat, and for 20 minutes at 160 ° C for the clear coat. After the above 2C1B, overcoat clear coating is applied. Then, for 2C1B, baking is performed at 140 ° C. for 20 minutes. As overcoat clear,
"Fluoronate HZ-790-60" (hydroxyl group-containing fluorine resin produced by Dainippon Ink and Chemicals, Inc.) and "Bernock DN-980" were blended so that OH / NCO = 1 (equivalent ratio). In addition, a coating material containing 50 ppm of "LO-50" was used with respect to the resin solid content <Evaluation criteria> 1) Metal unevenness on a vertical surface ... Visual determination ○ ... Almost unevenness No △: There is unevenness ×: There is a lot of unevenness 2) Smoothness ……………… Visual judgment ○… Good △… Inferior ×… Remarkably inferior 3) Hikarizawa ……………… 20 degrees Judgment by specular reflectance ○… 85% or more △… 60 or more and less than 85% ×… less than 60% 4) Water resistance ……………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………… ••••••••••••••• – Judgment by visual inspection ○: No abnormalities △: Slight blistering × ... the occurrence of swelling, which is a significant

[0065]

As is clear from the results shown in Table 1, the water-based coating composition of the present invention is free from "metal unevenness", excellent in smoothness, good in gloss, and water-resistant. According to the coating method of the present invention, which is known to have extremely high practicability and is extremely highly practical, and which is carried out using such an extremely highly practical aqueous coating composition,
In addition to the prevention of environmental pollution, which is a coating material with excellent coating appearance and low pollution, there is no metal unevenness, and in addition to the various coating performances and water resistance described above. It can be seen that all of the advantages of the above are brought.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical indication C09D 175/04 PHR 8620-4J 201/06 PDM 6770-4J

Claims (8)

[Claims] 1. A general formula: [However, R ¹ , R ² and R ³ in the formula are respectively
It represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, which may be the same or different. ] An aqueous product of a fine particle polymer obtained by using an ethylenically unsaturated monomer having a 2-oxo-1,3-dioxolan-4-yl group represented by A water-based coating composition characterized by: 2. A general formula: [However, R ¹ , R ² and R ³ in the formula are respectively
It represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, which may be the same or different. ] An aqueous solution of a fine particle polymer obtained by using an ethylenically unsaturated monomer having a 2-oxo-1,3-dioxolan-4-yl group represented by the above and a curing agent are essential components. A water-based coating composition comprising: 3. A general formula: [However, R ¹ , R ² and R ³ in the formula are respectively
It represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, which may be the same or different. ] An aqueous solution of a fine particle polymer obtained by using an ethylenically unsaturated monomer having a 2-oxo-1,3-dioxolan-4-yl group represented by: a curing agent, and a curing catalyst, A water-based coating composition, which contains as an essential component. 4. The above-mentioned fine-particle polymer has at least two compounds represented by the following general formula: [However, R ¹ , R ² and R ³ in the formula are respectively
It represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, which may be the same or different. ] And an ethylenically unsaturated monomer (A) having a 2-oxo-1,3-dioxolan-4-yl group and a monomer having at least two ethylenically unsaturated groups in one molecule The fine particle polymer obtained by polymerizing the body (B) and the other copolymerizable ethylenically unsaturated monomer (C) in an aqueous medium is added to two or more primary and And / or a compound (D) having a secondary amino group and / or an allyl (meth) acrylate (E) are reacted, and then,
The reaction product thus obtained is polymerized with a carboxyl group-containing ethylenically unsaturated monomer (F) and another copolymerizable ethylenically unsaturated monomer (G), and then the carboxyl group is added. The aqueous coating composition according to any one of claims 1 to 3, which is obtained by neutralizing a group. 5. The aqueous coating composition according to claim 2, wherein the curing agent is a blocked polyisocyanate compound and / or a melamine resin. 6. The aqueous coating composition according to claim 2 or 3, wherein the curing agent is a compound having at least two primary and / or secondary amino groups in one molecule. 7. The aqueous coating composition according to claim 3, wherein the curing catalyst is a quaternary ammonium salt. 8. The aqueous coating composition according to any one of claims 1 to 7 as a base coat for forming a coating film by 2 coat 2 bake or 2 coat 1 bake or overcoat method. And / or using a water-based coating compounded with a metallic pigment.