JPH09310042A - Curable aqueous coating material composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject coating material composition containing an acrylic polymer having malonate group which is an active methylene site, a compound having plural ethylenically unsaturated bonds and a catalyst for promoting Michel reaction in the molecule and remarkably improved in weather resistance. SOLUTION: This composition contains (A) an acrylic polymer having plural malonic acid ester pendant groups in the molecule, (B) a compound having plural ethylenically unsaturated bonds in the molecule and (C) a catalyst (e.g. tetramethylammonium hydroxide) for promoting Michel reaction between the components A and B in the form of a solvent, a dispersion or emulsion in an aqueous medium. The component A is preferably an emulsion or suspension obtained by copolymerizing, e.g. a malonate group-containing acryl monomer with other copolymer monomer by an emulsion polymerization method or a suspension polymerization method. Furthermore, a molar ratio of active methylene: ethylenically unsaturated bond is preferably 3:1 to 1:3.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION The present invention relates to curable waterborne coating compositions.

From the viewpoint of resource saving and environmental protection, water-based coatings containing no organic solvent are of interest. Widely used emulsion paints have a film-forming mechanism that physically fuses emulsion particles by evaporation of water after coating, and is therefore suitable for bake-curing paints in terms of coating performance such as water resistance, solvent resistance, and chemical resistance. It does not reach.

A system utilizing a Michael addition reaction in which an active methylene group is added to a polarized double bond such as an α, β-unsaturated carbonyl group as a curing mechanism does not generate a reaction by-product and is newly formed. It has excellent characteristics such that the formed bond is a chemically stable carbon-carbon bond.

US Pat. No. 4,408,018 discloses a system in which an acrylic polymer having a plurality of acetoacetate pendant groups introduced into a polymer backbone is crosslinked with a crosslinking monomer such as trimethylolpropane triacrylate using a basic catalyst. Disclose.

Japanese Unexamined Patent Publication (Kokai) No. 5-247372 discloses a catalyst-free system for crosslinking a resin having an α, β-unsaturated carbonyl group capable of Michael addition with an active methine compound.

Japanese Unexamined Patent Publication (Kokai) No. 6-234954 discloses an aqueous coating composition utilizing the Michael reaction as a curing mechanism.

WO 95/16749 describes polyfunctional acetoacetylated polymers such as polymers of 2-acetoacetoxyethyl (meth) acrylate and polyfunctional (meth) acrylics such as urethane acrylate resins or polyols poly (meth) acrylate. Disclosed is a room temperature curable aqueous coating composition containing an acid derivative and a Michael reaction catalyst in the form of an aqueous solution, an aqueous suspension or an aqueous emulsion.

Active methylene compounds which can be used in the Michael addition reaction are derivatives of acetoacetic acid, cyanoacetic acid and malonic acid. In order to use the Michael addition reaction for a crosslinking reaction of a resin, a compound or polymer having a plurality of active methylene groups in a molecule must be used. The acrylic monomer having an acetoacetyl group is 2-acrylic.
Hydroxyethyl acrylate (HEA), and 2-
The active methylene group-containing acrylic polymers used in the prior art can be prepared from these acrylic polymers because they can be prepared relatively easily by reacting a diketene with a hydroxylalkyl (meth) acrylate such as hydroxyethylmethacrylate (HEMA). It is a polymer of an acrylic monomer containing an acetoacetoxy group, or a modified acrylic polyol obtained by similarly reacting an acrylic polyol with diketene.

However, it has been found that when an acrylic polymer having a malonate group instead of an acetoacetoxy group is used in a paint, the weather resistance is remarkably improved.

Acrylic polymers having a plurality of malonate pendant groups, particularly alkyl (meth) malonate, have been used as active methylene components of paints having a Michael addition reaction as a curing mechanism, regardless of whether they are water-based or solvent-based.
No system was known using polymers of acryloyloxyalkyl esters.

Therefore, the present invention provides a curable aqueous coating composition which uses an acrylic polymer having a malonate group as an active methylene moiety instead of an acetoacetyl group as an active methylene component of a Michael reaction.

DISCLOSURE OF THE INVENTION The present invention relates to (a) an acrylic polymer having a plurality of malonate ester pendant groups in the molecule, (b) a compound having a plurality of ethylenically unsaturated bonds in the molecule, and (c) )
It relates to a curable aqueous coating composition comprising a catalyst for promoting the Michael reaction between the components (a) and (b) in the form of a solution, dispersion or emulsion in an aqueous medium. The present invention also relates to an aqueous emulsion or aqueous suspension for use as the component (a) of the above aqueous coating composition.

Preferred Embodiment Component (a) Component (a) can be produced by copolymerizing a malonic ester-bonded acrylic monomer with another acrylic monomer and / or a non-acrylic monomer.

The acrylic monomer having a malonic acid ester bonded thereto can be represented by the following formula.

[0015]

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In the formula, R ¹ is hydrogen or a methyl group, R ² and R ³ are alkylene groups having 2 to 6 carbon atoms, and R ⁴ is an alkyl group having 1 to 10 carbon atoms. n is an integer of 1 to 10, m is 0 or an integer of 1 to 6 when n = 1, and n> 1.
Is 0 when. Preferred monomers are those in which R ² is —CH ₂ CH ₂ — and n = 1, m = 0 in the above formula. These monomers are HEA and HE
It can be produced by a transesterification reaction between a hydroxyalkyl (meth) acrylate such as MA and a dialkyl ester of malonic acid.

Other monomers are lactone adducts of hydroxyalkyl (meth) acrylates such as HEA and HEMA (PCL-FA and P from Daicel Chemical Industries Ltd.).
Monomers (n = 1, m = 1 to 6) having a malonate group bonded by transesterification with malonic acid diester (such as those sold as CL-FM series), or ring-opening addition polymerization of ethylene oxide, propylene oxide or tetrahydrofuran A monomer (n = n) obtained by transesterifying the mono (meth) acrylate of polyoxyalkylene glycol obtained by
1 to 10 and m = 0).

Acrylic monomers usable for copolymerization include methyl, ethyl, propyl, n-butyl, i-butyl, t-butyl of acrylic acid or methacrylic acid,
2-ethylhexyl, lauryl, phenyl, benzyl,
Such as 2-hydroxyethyl, 2-hydroxypropyl ester, PCL-FM-1 (addition product of 2-hydroxyethyl acrylate and polycaprolactone, manufactured by Daicel Chemical Industries, Ltd.), acrylamide, and N-methylol acrylamide. There are derivatives thereof, such as acrylonitrile, and non-acrylic monomers include styrene and
Examples include α-methylstyrene, itaconic acid, maleic acid and vinyl acetate. In order to make an aqueous paint, the component (a) must be an aqueous varnish. One of the methods for this purpose is to copolymerize the above-mentioned malonic acid ester-bonded acrylic monomer with another acrylic and / or non-acrylic copolymerizable monomer by a solution polymerization method, and optionally after removing the solvent, an emulsifier or a suspension. It can be used by emulsifying or dispersing in water using a turbidity agent. As the emulsifier, a conventional anion, cation, nonionic, or amphoteric surfactant is used, and a water-soluble polymer compound such as polyvinyl alcohol, hydroxyethyl cellulose, carboxymethyl cellulose, or polyacrylic acid is used as a dispersion stabilizer, ( The component a) may be mechanically dispersed in an aqueous medium. In addition, a malonic acid ester-bonded acrylic monomer is solution-weighted using a monomer having an acid group such as acrylic acid or methacrylic acid as a part of the copolymerization monomer or a basic monomer such as dimethylaminoethyl (meth) acrylate. It is also possible to copolymerize by a conventional method and, if necessary, remove the solvent, neutralize at least a part of the acid group or the basic group, and dissolve or disperse in an aqueous medium to obtain an aqueous varnish. Copolymerized with an epoxy group-containing monomer such as glycidyl (meth) acrylate to give a primary or secondary monomer.
It is also possible to open the epoxy ring with a primary amine to introduce a basic group. It is also possible to use a monomer having a hydrophilic group such as polyethylene glycol (meth) acrylate as a copolymerization monomer to prepare an aqueous varnish.

The most preferred method is to obtain an emulsion or suspension by copolymerizing a malonate group-containing acrylic monomer with another copolymerizable monomer by an emulsion polymerization method or a suspension polymerization method. In the emulsion polymerization method, the above-mentioned conventional surfactant is used as an emulsifier, and the initiator is potassium persulfate, ammonium persulfate, 4,4′-azobis (4-cyanovaleric acid),
2,2'-azobis (2-methylpropionamidine)
Dihydrochloride (V-50), 2,2'-azobis (N, N '
-A water soluble initiator such as dimethylene isobutyroamidine) (VA-061) is used. As the emulsifier, a commercially available reactive emulsifier, for example, Antox MS-60.
(Nippon Emulsifier), Aqualon HS-10 (Daiichi Kogyo Seiyaku Co., Ltd.), ADEKA REASOAP SE-10N (Asahi Denka Kogyo) or the like may be used.

In the suspension polymerization method, the above-mentioned water-soluble polymer compound is used as a dispersion stabilizer, and azobisisobutyronitrile, 2,2'-azobis (2
-Methylbutyronitrile), 2,2'-azobis (2,2
Oil-soluble initiators such as 4-dimethylvaleronitrile), benzoyl peroxide, parachlorobenzoyl peroxide, lauroyl peroxide, t-butyl perbenzoate are used.

When a polyfunctional monomer is used as a part of the monomer mixture in the emulsion polymerization or suspension polymerization method, the inside of the component (a) is crosslinked and the crosslink density of the coating film can be increased.
Also, the ratio of active methylene monomers can be lowered to obtain coatings with the same crosslink density. Such polyfunctional monomers include divinylbenzene, polyhydric alcohol poly (meth) acrylate, and the like. The addition of polyfunctional monomers allows the crosslink density of the coating to be increased or the proportion of active methylene group containing monomers to be correspondingly reduced to obtain the desired level of crosslink density.

To control the molecular weight of the polymerization, mercaptans such as dodecyl mercaptan and octyl mercaptan, molecular weight regulators such as α-methylstyrene dimer and carbon tetrachloride may be added to the monomer mixture.

A polymer of a malonic acid ester-bonded acrylic monomer has an active hydrogen equivalent of 100 to 1 in the active methylene group.
It is preferred to have 50,000, especially 150 to 5,000.

A compound having two or more radically polymerizable ethylenically unsaturated groups in the molecule of component (b) can be used. As an example thereof, a polymerizable unsaturated monocarboxylic acid ester compound of polyhydric alcohol (for example, ethylene glycol diacrylate,
Ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, 1,4-butanedioldi Acrylate, neopentyl glycol diacrylate, neopentyl glycol dimethacrylate, 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, pentaerythritol diacrylate, pentaerythritol dimethacrylate, pentaerythritol triacrylate, Pentaerythritol trimethacrylate, pentaerythritol tetraacrylate, pentaerythritol Lumpur tetra methacrylate, glycerol diacrylate, glycerol dimethacrylate, glycerol Acro alkoxy dimethacrylate,
1,1,1-Trishydroxymethylethane diacrylate, 1,1,1-Trishydroxymethylethane dimethacrylate, 1,1,1-Trishydroxymethylethane triacrylate, 1,1,1-Trishydroxymethylethane Trimethacrylate, 1,1,1-trishydroxymethylpropane diacrylate, 1,
1,1-trishydroxymethylpropane dimethacrylate, etc.), an adduct of an epoxy group-containing ethylenically unsaturated monomer and a carboxyl group-containing ethylenically unsaturated group monomer (for example, glycidyl acrylate or glycidyl methacrylate) Acrylic acid, reaction product with methacrylic acid, etc.).

These ethylenically unsaturated compounds can be used alone or in admixture of two or more.

A (meth) acrylate of a polyhydric alcohol / ethylene oxide adduct, for example, trimethylolpropane-ethylene oxide adduct triacrylate (such as TMPTA-30E manufactured by Shin-Nakamura Chemical Co., Ltd.) is water-soluble (b).
It is an example of a component.

As the method for preparing the component (b) as an aqueous dispersion for use in an aqueous coating composition, a conventional emulsifier or dispersion stabilizer may be used to mechanically emulsify or disperse in an aqueous medium. Further, the component (b) is emulsion-polymerized (a).
It may be added directly to the component emulsion.

There are many known catalysts that promote the Michael addition reaction of the component (c) , including Lewis bases and Bronsteds bases. They are alkali metal hydroxides such as potassium hydroxide and sodium hydroxide, alkali metal carbonates such as potassium carbonate and sodium carbonate, quaternary ammonium bases and their carbonates, organic acid salts and halides.

Although quaternary ammonium compounds having various cation moieties can be used, tetraalkylammonium salts and trialkylaralkylammonium salts in which at least a part of alkyl groups may be substituted with hydroxyl groups are easily available. A quaternary ammonium salt of a nitrogen-containing heterocyclic compound such as pyridine, piperidine, piperazine, and morpholine may be used. Specifically, tetrabutylammonium, tetramethylammonium, tetraethylammonium, trimethylbenzylammonium, tetrapropylammonium, tetrahexylammonium, tetraoctylammonium, tetradecylammonium, tetrahexadecylammonium, triethylhexylammonium, 2-hydroxyethyltrimethylammonium. (Choline), methyltrioctylammonium, cetyltrimethylammonium, 2-chloroethyltrimethylammonium, and methylpyridinium.

The counter anion is hydroxide, halide, carboxylate, sulfonate, sulfate and the like. Specific examples include acetate, laurate, glycolate, benzoate, salicylate, chloride, bromide, iodide, methanesulfonate, p-toluenesulfonate, dodecylbenzenesulfonate, triflate, nitrate, sulfate, and metsulfate.

When a quaternary ammonium salt is used, an epoxy compound can be used in combination as disclosed in Japanese Patent Application No. 5-292736 of the present applicant.

Amidines and guanidines can also be used as catalysts. When the component (a) is produced by emulsion polymerization as described above, V-5 is used as an initiator.
By using an initiator having an amidine structure at the terminal, such as 0 or VA-061, the remaining amidine skeleton sufficiently exerts its function as a catalyst.

The coating composition (a) component, (b) component and (c) component can be blended as one liquid, or they can be separately stored separately and stored as a two-liquid composition. it can.

The ratio of component (a) / component (b) is, of course, preferably a stoichiometric ratio, but fluctuations in the molar ratio of functional groups in the range of 3/1 to 1/3 are permissible. It
The addition amount of the component (c) is 0.1 to 10% with respect to the total solid content weight of the component (a) and the component (b).

The coating composition of the present invention comprises a conventional extender pigment,
Color pigments, organic solvents for adjusting film-forming properties, surface conditioners,
Conventional additives such as defoamers and viscosity modifiers may be included.

The production examples, examples and comparative examples are shown below, in which "parts" and "%" are based on weight.

Production Example 1 In a flask equipped with a stirrer, a condenser tube and a dropping funnel,
Charge 200 parts of deionized water and 1.2 parts of Antox MS-60 (reactive emulsifier manufactured by Nippon Emulsifier Co., Ltd.) at 80 °
The temperature was raised to. Then an initiator consisting of 120 parts of deionized water and 1.2 parts of potassium persulfate, 280 parts of deionized water, A
ntox MS-60 3.2 parts, ethyl malonate 2-
A monomer pre-emulsion prepared in advance from (methacryloyloxy) ethyl (hereinafter referred to as ethoxymalonyloxyethyl methacrylate or EMEM) 118.6 parts, styrene 64 parts, methyl methacrylate 105.4 parts, and 2-ethylhexyl acrylate 112 parts for 2 hours. It dripped over. Then, the content was kept at 80 ° C. for 1 hour to obtain an emulsion. To this, 60 parts of a 2.5% tetramethylammonium hydroxide aqueous solution was added to adjust the pH to 7.5. Solid content 38%, particle size 16
0 nm (by laser light scattering method; the same applies hereinafter)

Production Example 2 As a monomer mixture, 244 parts of EMEM, 40 parts of styrene (ST), and 4 parts of methyl methacrylate (MMA).
6.4 parts, 2-ethylhexyl acrylate (2-EH
A) In the same manner as in Production Example 1 except that 69.6 parts were used,
An emulsion having a solid content of 38% and a particle diameter of 170 nm was obtained.

Production Example 3 As a monomer mixture, 9.1 parts of EMEM, ST40
Parts, MMA 161.3 parts, 2-EHA 149.6 parts, and ethylene glycol dimethacrylate 40 parts, in the same manner as in Production Example 1 with a solid content of 38% and a particle diameter of 155.
A 0 nm emulsion was obtained.

Production Example 4 As a monomer mixture, EMEM 118.6 parts, ST6
4 parts, MMA101.4 parts, 2-EHA110 parts, acrylic acid 4 parts, dodecyl mercaptan (molecular weight modifier) 2
The solid content was 38% in the same manner as in Production Example 1 except that parts were used.
%, An emulsion having a particle diameter of 170 nm was obtained.

Production Example 5 (for Comparative Example) As a monomer mixture, 104 parts of 2-acetoacetoxyethyl methacrylate (AAEM), ST64 parts, MM
An emulsion having a solid content of 38% and a particle diameter of 160 nm was obtained in the same manner as in Production Example 1 except that 120 parts of A and 112 parts of 2-EHA were used.

Production Example 6 (Pigment Dispersion) 25% aqueous solution 10 obtained by neutralizing SMA-1440 (a pigment dispersion resin manufactured by ATOCHEM, acid value 180) with an equivalent amount of tetramethylammonium hydroxide.
Part, titanium dioxide 100 parts, and deionized water 33 parts were prepared. Titanium dioxide content 70%

Example 1 (white enamel) To 1065.6 parts of the emulsion of Production Example 1 was added 45.7 parts of A-TMM-3L (pentaerythritol tri / tetraacrylate) manufactured by Shin Nakamura Chemical Co., Ltd. with stirring. Then, 570 parts of the pigment dispersion of Production Example 6 was mixed to obtain a white enamel. The paint was applied to a tin plate with an 8 mil doctor blade and dried at room temperature for 1 week. The initial 60 ° gloss value of the obtained coating film was 86.

Next, the coating film is subjected to accelerated weathering test QUV500h.
(Using Suga Test Instruments Co., Ltd. type DPWL-5, light irradiation 70 ° C. × 8 h, dew condensation 50 ° C. × 4 h, total of 12 h was set as one cycle, and this was repeated for 500 h.). The 60 ° gloss value of the coating film after the test was 85.

Examples 2 to 4 and Comparative Example 1 White enamel was prepared in the same manner as in Example 1 except that the formulation was changed as shown in Table 1. A coated plate was similarly prepared using this paint and tested. The results are shown in Table 1.

Example 5 and Comparative Example 2 (Clear Paint) A clear paint was prepared without adding the pigment dispersion in Example 4 and Comparative Example 1, and a coating film was similarly prepared and tested. The results are shown in Table 1.

[0047]

[Table 1]

It can be seen from Table 1 that the coating material using the EMEM polymer has better weather resistance than the coating material using the AAEM polymer.

Example 6 In Preparation Example 1, the emulsion was neutralized with a dimethylethanolamine aqueous solution instead of the tetramethylammonium hydroxide aqueous solution. Solid content 38%, particle size 160 nm, active hydrogen equivalent 417

To 1065.6 parts of this emulsion AT
MM-3L (45.7 parts), phthalic acid diglycidyl ester (DGP) (10 parts), and 5% tetrabutylammonium bromide (TBABr) aqueous solution (19 parts) were added to obtain a clear paint. This paint was applied to a tin plate with an 8 mil doctor blade and baked at 140 ° C. for 20 minutes to form a coating film, which was tested. Table 2 shows the results.

Example 7 To 1600 parts of deionized water Kuraray Popal PVA-217
Dissolve 20 parts of EE (manufactured by Kuraray) and add it to EMEM11
8.6 parts, ST64 parts, MMA105.4 parts, 2-EH
A monomer mixture consisting of A112 and 8 parts of lauroyl peroxide was added and suspended. This suspension at 80 ° C
The temperature was raised to and held for 3 hours. A white suspension with a solids content of 20.7% was obtained. Active hydrogen equivalent of active methylene 417

A-TMM-3L was added to 2012 parts of this suspension.
45.7 parts and 60 parts of 2.5% tetramethylammonium hydroxide (TMAOH) aqueous solution were added,
I got a clear paint. Using this paint, a coated plate was prepared in the same manner as in Example 1 and tested. Table 2 shows the results.

Comparative Example 3 AAEM 104 as the monomer mixture in Example 7
Section, ST64 section, MMA120 section, 2-EHA112
And 8 parts of lauroyl peroxide were used. Table 2 shows the results.

Example 8 A flask similar to that used in Preparation Example 1 was charged with methoxypropanol 36.
0 part was charged and heated to 110 ° C. To this EMEM1
18.6 parts, ST64 parts, MMA90 parts, acrylic acid 1
5.4 parts, 2-EHA 112 parts, and Kayaester O
(Kayaku Akzo t-butyl peroxy octoate)
A mixture of 18 parts was added dropwise over 3 hours and then 1
Hold at 10 ° C for 0.5 hours. Next, Kayaester O2
Part, and a mixture of 40 parts of methoxypropanol were added dropwise over 30 minutes, and the mixture was kept at 110 ° C. for 1.5 hours. The resulting acrylic resin solution had a nonvolatile content of 51.2%, a number average molecular weight of about 6000 (by the GPC method), an active hydrogen equivalent of active methylene of 430, and an acid value of 28.6.

820 parts of the above resin solution and A-TMM-3
L 45.7 parts were mixed, and further 10% tetramethylammonium hydroxide aqueous solution 194.6 parts was added,
Add 104 parts of deionized water and disperse to obtain a solid content of 22.8%.
In water. Using this dispersion, a coating film was prepared and tested in the same manner as in Example 1. Table 2 shows the results.

Comparative Example 4 In Example 8, AAEM10 was used as the monomer mixture.
4 parts, ST 64 parts, MMA 104.6 parts, acrylic acid 1
The same operation was performed except that the mixture was changed to 5.4 parts, 2-EHA 112 parts, and Kayaester O 20 parts. Table 2 shows the results
Shown in

Example 9 A flask similar to that used in Preparation Example 1 was charged with methoxypropanol 36.
0 part was charged and heated to 110 ° C. To this EMEM1
18.6 parts, ST64 parts, MMA105.4 parts, 2-E
A mixture of 112 parts of HA and 18 parts of Kayaester O was added dropwise over 3 hours, and then the mixture was kept at 110 ° C. for 0.5 hours. Then, a mixture of 2 parts of Kayaester O and 40 parts of methoxypropanol was added dropwise over 30 minutes, and further 1 part was added.
Hold at 10 ° C for 1.5 hours. The obtained resin solution had a nonvolatile content of 51.2%, a number average molecular weight of 5,500, and an active hydrogen equivalent of 430 of active methylene.

820 parts of the above resin solution and A-TMM-3
L 45.7 parts was mixed, and further Rhodapex CO-
436 (Rhone, Poulenc anionic surfactant) 1
0 part and 700.3 parts of deionized water were added and emulsified with a disper to obtain an emulsion having a solid content of 30%. To this emulsion was added 40 parts of a 10% tetramethylammonium hydroxide aqueous solution to obtain a clear coating. A coating film was prepared and tested in the same manner as in Example 1 using this paint. Table 2 shows the results.

[0059]

[Table 2]

From the results in Table 2, it can be seen that the coating material using the EMEM polymer has better weather resistance than the coating material using the AAEM polymer.

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Claims (17)

[Claims] 1. An acrylic polymer having (a) a plurality of malonate ester pendant groups in the molecule, (b) a compound having a plurality of ethylenically unsaturated bonds in the molecule, and (c) the component (a). And (b) a curable aqueous coating composition comprising a catalyst for promoting a Michael reaction between the components in the form of a solution, dispersion or emulsion in an aqueous medium. 2. In the acrylic polymer having a plurality of malonic acid ester pendant groups in the molecule, one carboxyl group of malonic acid is esterified with hydroxyalkyl (meth) acrylate and the other carboxyl group is alkyl ester. The coating composition according to claim 1, which is a polymer of an acrylic monomer. 3. The component (a) is an aqueous emulsion obtained by copolymerizing the acrylic monomer and an ethylenically unsaturated monomer copolymerizable therewith by an emulsion polymerization method. Coating composition. 4. The component (a) is an aqueous suspension obtained by copolymerizing the acrylic monomer and an ethylenically unsaturated monomer copolymerizable therewith by a suspension polymerization method. Coating composition. 5. The component (a) is a solution obtained by copolymerizing the acrylic monomer and an ethylenically unsaturated monomer copolymerizable therewith by a solution polymerization method, and dissolving or dispersing in water. Alternatively, the coating composition according to claim 2, which is an emulsion or an aqueous dispersion. 6. The component (a) has an active hydrogen equivalent of an active methylene group of 100 to 10,000.
The coating composition of any one of. 7. The coating composition according to claim 1, wherein the compound having a plurality of ethylenically unsaturated bonds in the molecule is an acrylic acid or methacrylic acid ester of a polyhydric alcohol. 8. The ratio of the components (a) and (b) is such that the molar ratio of active methylene: ethylenically unsaturated bond is 3: 1 to 1: 3. The coating composition of any one of. 9. The coating composition according to claim 1, wherein the component (c) is a quaternary ammonium salt group or a salt thereof. 10. The coating composition according to claim 1, wherein the component (c) is a combination of a quaternary ammonium salt and an epoxy compound. 11. The coating composition according to claim 1, wherein the component (c) is an organic or inorganic strong base. 12. The amount of the component (c) is 0.1 to 10 of the total solid weight of the components (a) and (b).
% Of the coating composition according to any one of claims 1 to 11. 13. The formula: (In the formula, R ¹ is hydrogen or a methyl group, R ² and R ³ are alkylene groups having 2 to 6 carbon atoms, R ⁴ is an alkyl group having 1 to 10 carbon atoms, n is an integer of 1 to 10, and m is n. 0 when = 1
It is an integer of 1 to 6, and is 0 when n> 1. 3.) An acrylic polymer obtained by copolymerizing the malonate group-containing acrylic monomer of 1) and a monofunctional ethylenically unsaturated monomer containing no malonate group by an emulsion polymerization method or a suspension polymerization method in an aqueous medium. 14. The acrylic polymer according to claim 13, which further contains a small proportion of a polyfunctional ethylenically unsaturated monomer as a copolymerization component. 15. The acrylic polymer according to claim 13, which has an active hydrogen equivalent of 100 to 10,000. 16. The acrylic polymer according to claim 15, which has an active hydrogen equivalent of 150 to 5,000. 17. The formula: (In the formula, R ¹ is hydrogen or a methyl group, R ² and R ³ are alkylene groups having 2 to 6 carbon atoms, R ⁴ is an alkyl group having 1 to 10 carbon atoms, n is an integer of 1 to 10, and m is n. 0 when = 1
It is an integer of 1 to 6, and is 0 when n> 1. ) A malonate group-containing acrylic monomer and a monofunctional ethylenically unsaturated monomer that does not contain a malonate group are copolymerized in an organic solvent to obtain an acrylic polymer, which is dissolved or dispersed in an aqueous medium. Aqueous varnish obtained by