JPH0532933A - Aqueous coating composition and coating by using the same composition - Google Patents

Abstract

PURPOSE:To provide an aqueous coating composition low in environmental pollution and capable of forming a coating film excellent in smoothness, gloss and weather resistance, free from sag, unevenness of metal-like gloss, etc., and showing an excellent visual appearance. CONSTITUTION:With a fine particle polymer obtained from (A) an ethylenic unsaturated monomer having a 2-oxo-1, 3-dioxolan-4-nyl group represented by the formula (R1-R3 are H or 1-4C alkyl), (B) a monomer containing two or more ethylenically unsaturated groups in one molecule and (C) another ethylenically unsaturated monomer copolymerizable therewith, (D) a compound having two or more primary and/or secondary amino groups in one molecule and (E) an ethylenically unsaturated monomer having a primary and/or secondary amino group and/or (F) an ally (meth) acrylate are reacted. To the resultant reaction product, (G) an ethylenically unsaturated monomer having an oxyethylene part and (H) another copolymerizable ethylenically unsaturated monomer are polymerized to obtain an aqueous core/shell type polymer particle. The resultant aqueous particles are blended with a curing agent and a curing catalyst, thus giving the objective coating composition.

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
-Oxo-1,3-dioxolan-4-yl group-containing ethylenically unsaturated monomer (A) and monomer (B) having at least two ethylenically unsaturated groups in one molecule
And another ethylenically unsaturated monomer (C) copolymerizable therewith in a fine particle polymer obtained by polymerizing in an aqueous medium, two or more primary and / or The compound (D) having a secondary amino group is reacted with the ethylenically unsaturated monomer (E) and / or allyl (meth) acrylate (F) having a primary and / or secondary amino group, and then, The reaction product thus obtained is obtained by polymerizing an ethylenically unsaturated monomer (G) having an oxyethylene moiety and another ethylenically unsaturated monomer (H) copolymerizable therewith. Comprising a hydrate of a particulate polymer obtained using a hydrate of a core / shell type 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. ] 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 A so-called emulsion in which a fine particle polymer obtained by polymerizing (B) and another copolymerizable ethylenically unsaturated monomer (C) in an aqueous medium is dispersed in water. Is to be 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)
The 2-oxo-1,3-dioxolan-4-yl group (hereinafter, also referred to as a cyclocarbonate group) present in the fine particle polymer (1) by adding the compound (D) having a secondary and / or secondary amino group. Internal cross-linking is carried out by reacting with a part of.

On the other hand, by reacting with an ethylenically unsaturated monomer (E) having a primary and / or secondary amino group through a cyclocarbonate group and an amino group, the surface of the particulate polymer is polymerized. It is possible to introduce an unsaturated group, and by using allyl (meth) acrylate (F), the unsaturated group of the (meth) acryloyl moiety mainly remains 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 chain, the ethylenically unsaturated monomer (G) having an oxylene moiety, and another copolymerizable ethylenically unsaturated monomer (H) are polymerized,
Further, the carboxyl group is neutralized to form a shell portion, whereby 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,

[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 realized, whereas if the amount exceeds 80 parts by weight, the subsequent addition reaction with the ethylenically unsaturated monomer (G) having an oxyethylene moiety is inevitable. Finally, the dispersion stability is deteriorated, and as a result, spots are generated or gelation occurs.

Further, as the above-mentioned monomer (B) having at least two ethylenically unsaturated groups in one molecule,
Generally, any one may be used as long as it belongs to the class called polyfunctional vinyl monomer, but if only representative ones are exemplified, ethylene glycol di (meth) acrylate, triethylene glycol di ( (Meth) acrylate, tetraethylene glycol di (meth) acrylate, 1,3-dipropylene di (meth) acrylate,
Trimethylolpropane tri (meth) acrylate,
1,4-butanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,6-
Hexanediol di (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, glycerol di (meth) acrylate
Acrylate, 1,1,1-trishydroxymethylethane di (meth) acrylate, 1,1,1-trishydroxymethylethane tri (meth) acrylate, 1,
1,1-trishydroxymethylpropane di (meth) acrylate, 1,1,1-trishydroxymethylpropane tri (meth) acrylate, triallyl cyanurate, triallyl isocyanurate, diallyl terephthalate, diallyl phthalate, allyl (meth) Starting with acrylate or divinylbenzene,

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; and various monomers from the above to Examples thereof include an adduct of a maleic anhydride with a hydroxyl group-containing unsaturated monomer obtained by an addition reaction of ε-caprolactone with a group, and alkyl esters thereof.

Next, as described above, various cyclocarbonate group-containing ethylenically unsaturated monomers (A) and monomers having at least two ethylenically unsaturated groups in one molecule, respectively. Except for (B), other copolymerizable ethylenically unsaturated monomer (C), that is, copolymerizable with the above-listed monomers (A) and (B) As the other ethylenically unsaturated monomer (C),
To give only representative examples, (meta)
Various α, β-unsaturated mono- or dicarboxylic acids such as acrylic acid, maleic acid, fumaric acid or itaconic acid; or various α, such as monoethyl maleate, monobutyl maleate, monobutyl fumarate or monoethyl itaconate , Β-ethylenically unsaturated dicarboxylic acid and a monovalent alcohol having 1 to 4 carbon atoms; or various hydroxyl group-containing vinyl monomers such as 2-hydroxyethyl (meth) acrylate, Unsaturated monomers containing a carboxyl group in a form obtained by adding various acid anhydrides such as phthalic anhydride;

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 kinds of alkyl (meth) acrylates having an alkyl group having 1 to 22 carbon atoms, 2-ethoxyethyl (meth) acrylate, cyclohexyl (meth) acrylate or (meth) acrylonitrile, which do not contain a 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 type surfactants include higher alcohol sulfate ester salts, polyethylene glycol ether sulfate ester salts, amide sulfate ester salts, and the like. Among these, amine salt of lauryl sulfate or sodium or potassium salt, Examples thereof include amine salts of alkylallyl polyether sulfate or sodium or potassium salts.

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

Examples of nonionic emulsifiers include polyethylene glycol alkylphenyl ethers, and such nonionic reactive emulsifiers include polyethylene glycol (meta) having an alkyl ether at one end.
There are acryloyl oxyethers.

As the polymerization initiator used for emulsion polymerization, organic peroxides, azo type polymerization initiators and redox polymerization initiators 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, the ammonium salt of persulfate, sodium salt or potassium salt, hydrogen peroxide, etc.,

As the azo-based initiators, only the representative ones are 4,4'-azobis (4-cyanovaleric acid) and the like, and the redox polymerization initiators are only the representative ones. Hydrogen peroxide-ferrous salt, persulfate-sodium acid sulfite, cumene hydroperoxide-N, N-dimethylaniline and the like can be mentioned, but emulsion polymerization in the present invention can be carried out according to the kind of initiator. Is not particularly limited by.

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) 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, an 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 as described above. It is particularly representative.

The amount of the polyamine compound (C) to be used is appropriately in the range of an equivalent ratio of amino group / cyclocarbonate group of 0.01 to 0.5. 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 (E) 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 these monomers (E) used is such that the equivalent ratio of amino group / cyclocarbonate group is 0.01 to.
The range of 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.

The amount of allyl (meth) acrylate (F) to be reacted 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 (G) 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.

[0044]

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

The aqueous composition thus obtained is, if necessary, combined with a known conventional block polyisocyanate and / or a curing agent such as a melamine resin to obtain 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 (D) 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.

Further, in the aqueous composition, if necessary, 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 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, 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 conditions for baking at that time 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.

The clear paint used here includes
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.

[0056]

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. In the following, unless otherwise specified, parts and% are
All are based on weight.

Reference Example 1 (Preparation Example of Aqueous Product of Fine Particle Polymer) 1,300 parts of deionized water was placed in a flask equipped with a dropping device, a stirring device, a thermometer, a cooling pipe and a nitrogen gas introducing pipe. , 200 parts of 2,3-carbonate propyl methacrylate, 200 parts of methyl methacrylate, while heating it to 75-85 ° C. and stirring under nitrogen atmosphere,
200 parts of styrene, 36 parts of n-butyl methacrylate
100 parts of a mixture consisting of 0 part and 40 parts of neopentyl glycol dimethacrylate, 20 parts of sodium polyoxyethylene nonylphenyl ether sulphate salt, 5 parts of sodium persulfate and 200 parts of deionized water are added dropwise. The same conditions were maintained 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
Part and structural formula

[0059]

[Chemical 7]

(However, the average molecular weight of the polyoxyethylene part 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 the 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. , 200 parts of 2,3-carbonate propyl methacrylate, 100 parts of methyl methacrylate, 500 parts of n-butyl methacrylate, 170 parts of n-butyl acrylate and 10 parts of neopentyl glycol dimethacrylate with stirring under a nitrogen atmosphere. Then, 100 parts of a mixture of 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 the mixture was kept under 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. After that, 800 parts of deionized water and structural formula

[0065]

[Chemical 8]

(However, the average molecular weight of the polyoxyethylene part 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 dripped 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 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 dropping was completed, the emulsion was kept under the same conditions for 30 minutes to obtain an emulsion of the target non-internally crosslinked polymer. 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 finishing, respectively. It was The results are also shown in the same table.

[0072]

[Table 1]

<Explanation of Table Annotation> a) C-325 ....
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 △: Unevenness ×… Remarkably large 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

[0075]

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. ] 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 using the body (B) and the other ethylenically unsaturated monomer (C) copolymerizable therewith, has two or more primary and / or secondary groups in one molecule. A compound (D) having an amino group is reacted with an ethylenically unsaturated monomer (E) having a primary and / or secondary amino group and / or an allyl (meth) acrylate (F), and then obtained An ethylenically unsaturated monomer (G) having an oxyethylene moiety in the reaction product obtained,
Other ethylenically unsaturated monomer (H) copolymerizable with this
An aqueous coating composition comprising an aqueous product of core / shell type polymer particles obtained by polymerizing and 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. ] 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 using the body (B) and the other ethylenically unsaturated monomer (C) copolymerizable therewith, has two or more primary and / or secondary groups in one molecule. A compound (D) having an amino group is reacted with an ethylenically unsaturated monomer (E) having a primary and / or secondary amino group and / or an allyl (meth) acrylate (F), and then obtained An ethylenically unsaturated monomer (G) having an oxyethylene moiety in the reaction product obtained,
Other ethylenically unsaturated monomer (H) copolymerizable with this
An aqueous coating composition, comprising an aqueous product of core / shell type polymer particles obtained by polymerizing and a curing agent as essential components. 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. ] 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 using the body (B) and the other ethylenically unsaturated monomer (C) copolymerizable therewith, has two or more primary and / or secondary groups in one molecule. A compound (D) having an amino group is reacted with an ethylenically unsaturated monomer (E) having a primary and / or secondary amino group and / or an allyl (meth) acrylate (F), and then obtained An ethylenically unsaturated monomer (G) having an oxyethylene moiety in the reaction product obtained,
Other ethylenically unsaturated monomer (H) copolymerizable with this
An aqueous coating composition, comprising an aqueous product of core / shell type polymer particles obtained by polymerizing the above, 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.