JPH0525426A - Aqueous coating composition and method for applying the same - Google Patents

Abstract

PURPOSE:To provide a coating film improved in smoothness, gloss, weatherability, and appearance by formulating specific fine polymer particles into an aq. compsn. CONSTITUTION:Fine polymer particles obtd. by copolymerizing an ethylenically unsatd. monomer having a 2-oxo-1,3-dioxolan-4-yl group of the formula (wherein R<1>, R<2>, and R<3> are each 1-4C alkyl) with another copolymerizable ethylenically unsatd. monomer are reacted with a compd. having at least two primary and/or secondary amino groups in the molecule and an ethylenically unsatd. monomer having a primary and/or a secondary amino group in the molecule and/or allyl (meth)acrylate. The reactional product is copolymerized with an ethylenically unsatd. monomer having an oxyethylene group and another ethylenically unsatd. monomer copolymerizable therewith to give an aq. compsn. of the fine polymer particles of a core/shell type. The aq. compsn., a curative, and a cure catalyst are dispersed in water.

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 contains an aqueous product of a fine particle polymer obtained by using an ethylenically unsaturated monomer having a specific group called an yl group as an essential base resin component. Especially, from the viewpoint of both environmental pollution prevention and a finished appearance. The present invention relates to a novel and useful aqueous coating composition 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 problems to be solved as described above, as a result of intensive and repeated studies, three-dimensional internal crosslinked specific fine particles and a polymer for stabilizing the same are provided as specific means. Therefore, by using an aqueous coating composition obtained by chemically bonding, it was found that, particularly, a coating film having an excellent finished appearance can be formed,
Here, the present invention has been completed.

That is, according to the present invention, as an essential component, 2
By using an ethylenically unsaturated monomer (A) having a -oxo-1,3-dioxolan-4-yl group and another ethylenically unsaturated monomer (B) copolymerizable therewith Compound (C) having two or more primary and / or secondary amino groups in one molecule, and an ethylenically unsaturated monomer having primary and / or secondary amino groups in the obtained fine particle polymer. (D) and / or allyl (meth) acrylate (E) are reacted, and then the reaction product thus obtained can be copolymerized with an ethylenically unsaturated monomer (F) having an oxyethylene moiety and this. Core / obtained by polymerizing with another ethylenically unsaturated monomer (G)
Comprising a hydrated particulate polymer obtained using a hydrated shell-shaped polymer particle,

Alternatively, a specific water-based coating material containing an aqueous product of the fine particle polymer and a curing agent, or containing an aqueous product of the fine particle polymer, a curing agent and a curing catalyst. The present invention is intended to provide a composition, and further to provide a coating method (coating film forming method), which comprises using such a specific aqueous 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

[0011]

[Chemical 4]

[Wherein R1, R2 and R3 in the formula are
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, a method for internally cross-linking the 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 a part of.

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

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 a shell is polymerized with an ethylenically unsaturated monomer (F) having an oxylene moiety and another copolymerizable ethylenically unsaturated monomer (G) to form a shell. By forming a part, the desired aqueous coating composition having a core / shell structure can be prepared here.

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,

[0017]

[Chemical 5]

[Wherein R 1, R 2 and R 3 are as defined above, R 4 is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and n is
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
Appropriately within the range of 0.1 to 80 parts by weight, preferably 0.5 to 50 parts by weight. If the amount is less than 0.1 part by weight, the effect cannot be manifested, and if the amount exceeds 80 parts by weight, the subsequent addition reaction with the ethylenically unsaturated monomer having the oxyethylene moiety is inevitable. Dispersion stability is deteriorated, and as a result, spots are generated and gelation occurs.

Next, as described above, other copolymerizable ethylenically unsaturated monomers (B) except the various cyclocarbonate group-containing ethylenically unsaturated monomers (A), respectively, are listed. That is, as the other ethylenically unsaturated monomer (B) copolymerizable with the above-mentioned monomer (A), only typical ones are listed as follows: ) A variety of α, β-unsaturated mono-, such as acrylic acid, maleic acid, fumaric acid or itaconic acid
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.

As the compound (C) having two or more primary and / or secondary amino groups in one molecule, which is to be reacted with the fine particle polymer (1) thus obtained, aliphatic polyamine, aromatic polyamine, At least one selected from various known and commonly used polyamines such as 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 (C) used is appropriately in the range of 0.01 to 0.5 in terms of the equivalent ratio of amino group / cyclocarbonate group. If it is less than 0.01, the effect of internal crosslinking is insufficient,
On the other hand, when it exceeds 0.5, interparticle cross-linking tends to occur, which is not preferable in any case.

On the other hand, as the ethylenically unsaturated monomer (D) having a primary and / or secondary amino group to be reacted with the fine particle polymer (1), at least one primary or Any compound that has both a secondary amino group and an ethylenically unsaturated group may be used, and of these, 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 ethylenically unsaturated monomer (F) having an oxyethylene moiety to be copolymerized with the ethylenically unsaturated group introduced on the surface of the reaction product (2) thus obtained is A general formula in which the polyoxyethylene moiety has an average molecular weight of 500 to 15,000.

[0041]

[Chemical 6]

[Wherein R 5 and R 6 are each a hydrogen atom or an alkyl group having 1 to 4 carbon atoms,
A phenyl group or a carboxyl group, R7 represents an alkyl group having 1 to 20 carbon atoms, and n represents the number of repeating units of an oxyethylene bond. ] A compound as shown by these is meant.

Specifically, it has the average molecular weight as described above, but one end of the polyoxyethylene moiety is 1
To prepare a polyethylene glycol having an alkyl group having a carbon number of ~ 20 and a hydroxyl group at the other end, and then adding this polyethylene glycol and a carboxyl group-containing ethylenically unsaturated monomer such as acrylic acid or methacrylic acid. It can be obtained by a transesterification reaction with a compound, or can also be obtained by a reaction of the polyoxyethylene glycol with an acid chloride group-containing ethylenically unsaturated monomer, or the polyoxyethylene glycol with an acid anhydride group. It can also be obtained by reaction with the contained ethylenically unsaturated monomer.

Next, the other copolymerizable ethylenically unsaturated monomer (G) other than the above-mentioned ethylenically unsaturated monomer (F) having an oxyethylene moiety is prepared.
As the above, at least one selected from various monomers (B) may be used.

The aqueous composition thus obtained is optionally combined with a known curing agent such as a blocked polyisocyanate and / or a melamine resin to give a carboxyl group and / or a carboxyl group in the aqueous composition. A cured coating film can be obtained by reacting with a hydroxyl group and curing, and by adding a compound having at least two primary and / or secondary amino groups in one molecule as such a curing agent, it remains. It can be reacted with a cyclocarbonate group to be cured to obtain a cured coating film, and further, as a curing catalyst, 4
By blending the primary ammonium salt, curing can be achieved through reaction between the remaining cyclocarbonate group and carboxyl group, self-condensation of the cyclocarbonate group, and the like.

Here, as the compound having at least two primary and / or secondary amino groups in one molecule, various compounds (C) as described above can be used, while 4 Examples of the quaternary ammonium salt include quaternary ammonium hydroxide represented by tetramethylammonium hydroxide and trimethylbenzylammonium hydroxide; or quaternary ammonium having a carboxylate anion represented by tetramethylammonium propionate as a counterion. Salt, etc.
It is particularly representative.

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, if necessary. , 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 is a 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, when used for automobiles and the like, the water-based paint thus obtained is used as a base coat for forming a coating film by a 2 coat 2 bake system, a 2 coat 1 bake system or an overcoat system. , A color pigment and / or a metallic pigment can be used in a mixed form.

The baking conditions in that case depend 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.

[0053]

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, 200 parts of 2,3-carbonate propyl methacrylate, 200 parts of methyl methacrylate,
200 parts of styrene, 38 of n-butyl methacrylate
0 parts and 20 parts of methacrylic acid, 20 parts of polyoxyethylene nonylphenyl ether sulfate sodium salt, 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
And 15 parts of 1,4-diaminobutane were added and the mixture was kept under the same conditions for 30 minutes to react the cyclocarbonate group with the amino group. Then, the structural formula

[0056]

[Chemical 7]

(However, the average molecular weight of the polyoxyethylene portion is 4,000.) 40 parts of the hydrophilic monomer and 2 parts of 2-hydroxypropyl methacrylate.
0 parts, 55 parts of methyl methacrylate and 35 parts of n-butyl acrylate, 5 parts of polyoxyethylene nonylphenyl ether sulfate sodium salt and 2 parts of sodium persulfate, and 5 parts of deionized water. It was added dropwise for 1 hour.

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-
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, 500 parts of n-butyl methacrylate, 180 parts of n-butyl acrylate and 20 parts of methacrylic acid, and poly 100 parts of a mixture consisting of 20 parts of oxyethylene 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 The mixture was added dropwise over 3 hours. Even after the dropping is completed, 1
Held for hours.

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 15 parts of 1,4-diaminobutane were added, and the mixture was kept under the same conditions for 30 minutes to react the cyclocarbonate group with the amino group. next,

[0062]

[Chemical 8]

(However, the average molecular weight of the polyoxyethylene portion is 4,000.) 40 parts, 20 parts of 2-hydroxypropyl methacrylate, 55 parts of methyl methacrylate and 35 parts of n-butyl acrylate, 5 parts of oxyethylene nonyl phenyl ether sulfate sodium salt and 2 parts of sodium persulfate
Part and 5 parts of deionized water were added dropwise over 1 hour.

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 the 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 amount of 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 completion of the 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 to evaluate the performance of various coating films obtained by 2 coat 2 bake or 2 coat 1 bake or overcoat finish, respectively. It was The results are also shown in the same table.

[0069]

[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.), deionized water was added, and neutralized with dimethylethanolamine to obtain 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 coating composition formulated so that NCO = 1 (equivalent ratio) and containing 50 ppm of "LO-50" with respect to the resin solid content. Powder paint ………… “Findick A-207
S ”[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% "Modaflow" (leveling agent manufactured by Monsanto Co., Ltd.) f) Type of finishing method: 1.2C1B .... Baking is 140C for 20 minutes 2.2C2B .... Baking. For 30 minutes at 80 ° C., 3.2C2B ... Baking is performed at 140 ° C. for 20 minutes for the base coat, and at 160 ° C. for 20 minutes for the clear coat.

<Evaluation Criteria> 1) Metal unevenness on a vertical surface ... Visual judgment ○ ... Almost no unevenness △ ... There is unevenness ×… Very unevenness 2) Smoothness …………… … Visual judgment ○… Good △… Inferior ×… Remarkably inferior 3) Hikarizawa ……………… Judgment by 20 degree specular reflectance ○… 85% or more △… 60 or more and less than 85% ×… Less than 60% 4 ) Water resistance ……………… Visually judge the state of the coated surface after soaking in water at 50 ° C for 7 days. ○… No abnormalities △… Blisters are slightly observed × Blisters occur But remarkable

[0072]

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.

Claims (7)

[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. ] The 2-oxo-1,3-dioxolan-4-yl group-containing ethylenically unsaturated monomer (A) and another ethylenically unsaturated monomer (B) copolymerizable therewith (B) And a compound (C) having two or more primary and / or secondary amino groups in one molecule, and an ethylenic polymer having primary and / or secondary amino groups in the molecule. The unsaturated monomer (D) and / or the allyl (meth) acrylate (E) are reacted, and the reaction product thus obtained is then mixed with the ethylenically unsaturated monomer (F) having an oxyethylene moiety, An aqueous product of core / shell type polymer particles, which is obtained by polymerizing this with another ethylenically unsaturated monomer (G) that is copolymerizable,
A water-based coating composition, which is contained as an essential base resin component. 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. ] The 2-oxo-1,3-dioxolan-4-yl group-containing ethylenically unsaturated monomer (A) and another ethylenically unsaturated monomer (B) copolymerizable therewith (B) And a compound (C) having two or more primary and / or secondary amino groups in one molecule, and an ethylenic polymer having primary and / or secondary amino groups in the molecule. The unsaturated monomer (D) and / or the allyl (meth) acrylate (E) are reacted, and the reaction product thus obtained is then mixed with the ethylenically unsaturated monomer (F) having an oxyethylene moiety, An aqueous product of core / shell type polymer particles obtained by polymerizing this with another ethylenically unsaturated monomer (G) that is copolymerizable,
A water-based coating composition comprising a curing agent as an essential component. 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. ] The 2-oxo-1,3-dioxolan-4-yl group-containing ethylenically unsaturated monomer (A) and another ethylenically unsaturated monomer (B) copolymerizable therewith (B) And a compound (C) having two or more primary and / or secondary amino groups in one molecule, and an ethylenic polymer having primary and / or secondary amino groups in the molecule. The unsaturated monomer (D) and / or the allyl (meth) acrylate (E) are reacted, and the reaction product thus obtained is then mixed with the ethylenically unsaturated monomer (F) having an oxyethylene moiety, An aqueous product of core / shell type polymer particles obtained by polymerizing this with another ethylenically unsaturated monomer (G) that is copolymerizable,
An aqueous coating composition comprising a curing agent and a curing catalyst as essential components. 4. The aqueous coating composition according to claim 2, wherein the curing agent is a blocked polyisocyanate compound and / or a melamine resin. 5. 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. 6. The aqueous coating composition according to claim 3, wherein the curing catalyst is a quaternary ammonium salt. 7. A water-based 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.