JP2003073612A - Water coating composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a one-portion water coating composition which is useful for protecting a building structure and maintaining a beautiful appearance thereof, and can be easily cured independent of the application environment. SOLUTION: This water coating composition contains a copolymer (I) obtained by copolymerizing a maleimide-containing ethylenically unsaturated monomer (a), a carbonylated ethylenically unsaturated monomer (b) and other ethylenically unsaturated monomer (c); a compound (II) having two or more same or different functional groups selected from hydrazide groups, semicarbazide groups and hydrazone groups in the molecule, and a pigment (III) with the volume concentration of the pigment being 10 to 70%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a one-pack type aqueous coating composition which is particularly useful for protecting architectural structures and maintaining aesthetics, and which can be easily cured regardless of the coating environment.

[0002]

2. Description of the Related Art In recent years, in the use of paints, attempts have been made to make paints water-based in response to environmental problems and demands for improvement of working environment. For example, in the case of water-based paints in the field of construction, dry at room temperature,
Although coatings having excellent coating performance such as weather resistance and stain resistance are required, they are insufficient in terms of coating performance as compared with solvent-based coatings.

As a composition for an aqueous permanent dry coating suitable for such building use, for example, JP-A-4-249587 discloses a composition containing emulsion particles containing a crosslinkable carbonyl group and a dihydrazide compound. There is. The composition can form a coating film having excellent storage properties and excellent physical properties such as water resistance, but the crosslinking reaction may not proceed sufficiently depending on the coating environment. For example, in coating in an environment where evaporation of water is extremely slow, such as when the temperature is low, there is a problem that the water resistance in the initial stage after coating (initial water resistance) is insufficient.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to solve the above-mentioned problems of conventional water-based, normally-dry, one-pack type coating compositions. Introducing a maleimide group that cures by irradiation of natural light into the copolymer containing it, and by supplementing the photo-curing by the maleimide group to the crosslinking reaction by the carbonyl group / cross-linking agent, the initial stage after coating regardless of the coating environment The inventors have found that a coating composition capable of forming a coating film having excellent water resistance and curability can be obtained even in the stage, and have completed the present invention.

Thus, according to the present invention, the ethylenically unsaturated monomer (a) having a maleimide group, the ethylenically unsaturated monomer (b) having a carbonyl group and the other ethylenically unsaturated monomer (c) are used. (I); a compound (II) having two or more same or different functional groups selected from a hydrazide group, a semicarbazide group and a hydrazone group per molecule (II); and a pigment (II).
An aqueous coating composition containing I) and having a pigment volume concentration in the range of 10 to 70%.

The aqueous coating composition of the present invention (hereinafter referred to as the composition of the present invention) will be described in more detail below.

In the present specification, an acryloyl group or a methacryloyl group is referred to as a (meth) acryloyl group, an acrylate or a methacrylate is referred to as a (meth) acrylate, and acrylic acid or methacrylic acid is referred to as (meth).
Acrylic acid is represented, acrolein or methacrolein is represented by (meth) acrolein, acrylamide or methacrylamide is represented by (meth) acrylamide, and an allyl group or a methallyl group is represented by a (meth) allyl group.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Copolymer (I) The copolymer (I) comprises a maleimide group-containing ethylenically unsaturated monomer (a) and a carbonyl group-containing ethylenically unsaturated monomer (b). It is a copolymer having a maleimide group and a carbonyl group in the molecule, which is obtained by copolymerizing with and other ethylenically unsaturated monomer.

In the present invention, the ethylenically unsaturated monomer (a) having a maleimide group is photodimerized by irradiation with natural light, and a maleimide for three-dimensionally crosslinking a coating film formed from the composition of the present invention. It is used for introducing a group into the copolymer (I).

The ethylenically unsaturated monomer (a) having a maleimide group includes a compound having an ethylenically unsaturated group and a cyclic imide group represented by the following formula (1) (hereinafter,
(Referred to simply as "imide compound").

[0011]

[Chemical 1]

In the formula, R ¹ and R ² are each independently a hydrogen atom or an alkyl group, or R ¹ and R ² are a group which forms a carbocycle together with the carbon atom to which they are bonded. Is.

Examples of the ethylenically unsaturated group in the above imide compound include vinyl, allyl, and (meth) acryloyl groups, and the (meth) acryloyl group is particularly preferable.

Further, R ¹ and R ² in the above formula (1) are each independently an alkyl group from the viewpoint of the polymerizability of imide compounds and the copolymerizability with other unsaturated monomers. It is preferably an alkyl group having 4 or less carbon atoms, or a group which forms a carbocyclic ring together, for example, a group -CH.
_{2 CH 2 CH 2 -, -} CH 2 CH 2 CH 2 CH 2 - is - like, preferably _{-CH 2 CH 2 CH 2 CH 2} .

Specific examples of the imide compound include imide (meth) acrylates represented by the following formula (2).

[0016]

[Chemical 2]

Where R¹And R²Is as defined above, and R
³Is an alkylene group, preferably an alkylene having 1 to 6 carbon atoms.
Group, more preferably ethylene or propylene group
R ^FourIs a hydrogen atom or a methyl group, and n is 1 to 6
It is an integer, preferably 1 or 2, and more preferably
Is 1.

Preferred examples of the imide (meth) acrylate include compounds represented by the following formulas (3) and (4).

[0019]

[Chemical 3]

[0020]

[Chemical 4]

In the formula, R ⁴ and R ⁵ are each independently a hydrogen atom or a methyl group, R ⁶ and R ⁷ are each independently an alkyl group having 4 or less carbon atoms, and n is an integer of 1 to 6 is there.

The imide (meth) acrylate is a compound known per se, for example, Kiyoshi Kato et al., Journal of Organic Synthetic Chemistry, 30 (10), 897, (1972); Javier.
deAbajo et.al, Polymer, vol33 (5),
1090, (1992); acid anhydrides, amino alcohols and (meth) by the methods described in JP-A-56-53119, JP-A-1-242569 and the like.
It can be produced from acrylic acid.

The ethylenically unsaturated monomer (b) having a carbonyl group is used for introducing a carbonyl group into the copolymer (I), and the carbonyl group is the compound (II) described later. When the photo-crosslinking by the maleimide group is insufficient, the copolymer (I) assists the crosslinking of the coating film by the crosslinking reaction with the functional group therein.

The ethylenically unsaturated monomer (b) having a carbonyl group has at least one carbonyl group selected from an aldehyde group and a keto group and a polymerizable double bond in one molecule. Monomers are preferable, and specific examples thereof include (meth) acrolein, formyl styrene, vinyl alkyl ketone having 4 to 7 carbon atoms (for example, vinyl methyl ketone, vinyl ethyl ketone, vinyl butyl ketone), diacetone ( (Meth) acrylamide etc. are mentioned. Of these, diacetone (meth) acrylamide is preferable because of its excellent reactivity with the compound (III) described below.

Other ethylenically unsaturated monomers (copolymerized with the ethylenically unsaturated monomer (a) having a maleimide group and the ethylenically unsaturated monomer (b) having a carbonyl described above ( Examples of c) include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate. , 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate and stearyl (meth) acrylate and other alkyl (meth) acrylates; cyclohexyl (meth) acrylate, isobornyl (meth) acrylate and other alicyclic (meth) acrylates; benzyl (Meth) acrylate, etc. Aralkyl (meth) acrylate; 2-methoxyethyl (meth) acrylate and 2
-Alkoxyalkyl (meth) acrylates such as ethoxyethyl (meth) acrylate; hydroxyalkyl (meth) acrylates such as hydroxyethyl (meth) acrylate and hydroxypropyl (meth) acrylate;
Vinyl ester compounds such as perfluoroalkyl (meth) acrylate, glycidyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, (meth) acrylic acid, (meth) acrylonitrile, vinyl acetate and vinyl propionate; styrene; Vinyl aromatic compounds such as α-methylstyrene; Ethylenically unsaturated monocyclic compounds having an alkoxysilyl group such as vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloyloxypropyltrimethoxysilane and γ-methacryloyloxypropyltriethoxysilane. Examples thereof include a polymer. Among these, as a preferable monomer in terms of copolymerizability, coating film physical properties, and particle stability, an alkyl (meth) acrylate having an alkyl group having 1 to 8 carbon atoms, (meth)
Examples thereof include acrylic acid, styrene, hydroxyalkyl (meth) acrylate having an alkylene group having 2 to 3 carbon atoms, and cyclohexyl (meth) acrylate is a preferable monomer from the viewpoint of weather resistance.

The copolymer (I) can be prepared, for example, according to a general emulsion polymerization method in the presence of a surfactant as an emulsifier,
Easily prepared by copolymerizing the above-mentioned maleimide group-containing ethylenically unsaturated monomer (a), carbonyl group-containing ethylenically unsaturated monomer (b) and other ethylenically unsaturated monomer (c) Can be manufactured.

In the emulsion polymerization, the maleimide group-containing ethylenically unsaturated monomer (a), the carbonyl group-containing ethylenically unsaturated monomer (b) and other ethylenically unsaturated monomers (c) are used. ) Is a monomer (a), (b),
Generally, 1 to 40% by weight of monomer (a), preferably 4 to 20% by weight, and 1 to 30% by weight of monomer (b), preferably 2 based on the total amount of (c). ~ 25% by weight,
And 40 to 98% by weight of the monomer (c), preferably 55
It can be used within the range of up to 94% by weight.

When the proportion of the monomer (a) used is less than 1% by weight, the physical properties of the coating film formed from the composition of the present invention such as initial water resistance immediately after coating in an environment where the evaporation of water is slow, deteriorates. On the other hand, if it exceeds 40% by weight, the cross-linking density of the coating film becomes too high and the coating film tends to become brittle. When the amount of the monomer (b) is less than 1% by weight, physical properties such as hardness, water resistance and stain resistance of the coating film formed from the composition of the present invention tend to decrease, while 30% by weight If it exceeds, the hydrophilicity of the coating film becomes high and the water resistance may decrease even after curing.

In the production of the copolymer (I), the emulsifier (surfactant) is usually used in emulsion polymerization, for example, sodium dialkylsulfosuccinate, sodium dodecylbenzenesulfonate, sodium lauryl sulfate and polyoxy. It is also possible to use anionic surfactants such as sodium ethylene alkylphenyl ether sulfate and sodium dialkyl diphenyl ether disulfonate, and nonionic surfactants such as polyoxyethylene higher alcohol ethers and polyoxyethylene alkylphenyl ethers. However, from the viewpoint of water resistance of the coating film formed using the finally obtained coating composition,
It is preferable to use radically polymerizable surfactants.
When a radically polymerizable surfactant is used as an emulsifier,
The radically polymerizable surfactant is incorporated into the copolymer as a third component.

Examples of the radical-polymerizable surface active agent include, for example, Japanese Patent Publication No. 46-12472 and Japanese Patent Publication No. 56-29.
657, JP-A-56-28208, JP-A-56-127697, JP-A-62-100502.
It is possible to use those known per se, such as those described in Japanese Patent Publication No. Hei 2-162287, and
Examples of commercially available products include "Latemur" (trade name, manufactured by Kao Corporation), "Eleminol" (trade name, manufactured by Sanyo Kasei Co., Ltd.), "Aqualon" (trade name, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) ), "Adeka rear soap" (trade name, manufactured by Asahi Denka Kogyo Co., Ltd.) and the like.

In the present invention, in particular, a surfactant having a polyoxyalkylene group as a main chain, a group having a radical polymerizable double bond at one end, and an ion dissociative group at the other end, more specifically, Specifically, for example, a compound represented by the following formula (5) is suitable. Z- (AO) n-Y (5) In the formula, Z is a group having a radical-polymerizable double bond,
AO is an oxyalkylene group, n is an integer of 2 or more, and Y is an ion dissociative group.

The radical-polymerizable double bond-containing group includes a hydrophobic group moiety such as an aromatic hydrocarbon group, an alkyl-substituted aromatic hydrocarbon group, a higher alkyl group or an alicyclic hydrocarbon group, and ( Examples thereof include those having a structure in which radical-polymerizable double bond-containing moieties such as (meth) allyl, propenyl and butenyl groups are combined.

The radical-polymerizable surfactant may be either anionic or cationic, but is preferably anionic. Therefore, as the ion dissociative group, an anion is covalently bonded to the oxyalkylene group. Then
Salt cation is ionically bound is preferable to, specifically, for example, _{-SO 3 Na, -SO 3 NH 4} , -COON
_{a, -COONH 4, -PO 3 Na} 2 , and -PO ₃ (NH _{4)
2 and the} like, among which —SO ₃ Na and —SO ₃ NH ₄ are preferable.

The repeating number n of oxyalkylene units in the polyoxyalkylene group is generally 300 or less, preferably 5 to 50, and the type of alkylene group is preferably ethylene or propylene group.

Specific examples of such radically polymerizable surfactants include compounds represented by the following formulas (6), (7) and (8).

[0036]

[Chemical 5]

[0037]

[Chemical 6]

[0038]

[Chemical 7]

In the above formula, R ⁸ and R ⁹ are linear or branched alkyl groups having 6 to 18 carbon atoms, R ¹⁰ is an alkyl group having 8 to 24 carbon atoms, and R ¹¹ is a hydrogen atom or It is a methyl group, and Y is the ion dissociative group described above.

The radical-polymerizable surfactant is used in an amount of the maleimide group-containing ethylenically unsaturated monomer (a), the carbonyl group-containing ethylenically unsaturated monomer (b) and other ethylenically unsaturated monomers. Although it depends on the type of the monomer (c), the type of the radical-polymerizable surfactant, and the like, generally, with respect to 100 parts by weight of the total amount of the monomers used,
It is preferably within the range of 0.1 to 5 parts by weight. If the amount of the radically polymerizable surfactant used is less than 0.1 part by weight, the stability of the emulsion obtained by emulsion polymerization using this may decrease, whereas if it exceeds 5 parts by weight, Not only is the improvement of the water resistance of the coating film in proportion to the addition amount not observed, but the water resistance tends to decrease.

From the viewpoint of improving the stability of the emulsion and the water resistance of the coating film, anionic polymer surfactants such as polycarboxylic acid-based and polysulfonic acid-based surfactants, non-ionic surfactants such as polyvinyl alcohol, etc. are not used during emulsion polymerization. An ionic polymer surfactant can also be used in combination, and the amount thereof is 0.1 parts by weight with respect to 100 parts by weight of the total amount of generally used monomers.
It is preferably within the range of 5 parts by weight.

Ethylenically unsaturated monomer having maleimide group (a), ethylenically unsaturated monomer having carbonyl group (b) and other ethylenically unsaturated monomer (c)
The emulsion polymerization of the above-mentioned monomers (a), (b),
A method in which the mixture of (c) is emulsified and dispersed in an aqueous medium using the above-described surfactant, a polymerization initiator is added, and the mixture is heated and stirred, and the monomers (a), (b), (c) are used. ) And a surfactant as described above are first used to prepare an aqueous emulsion, and the aqueous emulsion is added to an aqueous medium containing a polymerization initiator while heating and stirring. it can. At that time, a chain transfer agent may be used, if necessary, in order to control the molecular weight of the produced copolymer.

Examples of the above-mentioned polymerization initiator include persulfates such as potassium persulfate and ammonium persulfate; peroxides such as hydrogen peroxide, benzoyl peroxide and t-butyl hydroperoxide. Uses a reducing agent such as sodium bisulfite, ascorbic acid,
You may use it as a redox type initiator. Of these, water-soluble polymerization initiators are particularly preferable. Examples of the chain transfer agent include dodecyl mercaptan,
Xanthogenic acid disulfide, diazothioether, 2
-Propanol and the like.

Copolymer (I) obtained as described above
Is generally 1000 to 1,000,000, preferably 10
It can have a number average molecular weight in the range of 5,000 to 500,000. In this specification, the number average molecular weight is a value obtained by converting the molecular weight measured by gel permeation chromatography using tetrahydrofuran as a solvent based on the molecular weight of polyethylene. Compound (II) The composition of the present invention comprises, as a cross-linking agent which reacts with the carbonyl group contained in the copolymer (I), two same or different functional groups selected from a hydrazide group, a semicarbazide group and a hydrazone group per molecule. The compound (II) having the above is contained.

Examples of the compound (II-1) having two or more hydrazide groups per molecule include carbon number of oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, sebacic acid dihydrazide and the like. A dihydrazide of a saturated aliphatic carboxylic acid of 2 to 18; maleic acid dihydrazide,
Dihydrazides of monoolefinic unsaturated dicarboxylic acids such as fumaric acid dihydrazide and itaconic acid dihydrazide;
Phthalic acid, terephthalic acid or isophthalic acid dihydrazide; pyromellitic acid dihydrazide, trihydrazide or tetrahydrazide; nitrilotriacetic acid trihydrazide, citric acid trihydrazide, 1,2,4-benzenetrihydrazide; ethylenediaminetetraacetic acid tetrahydrazide; 1, 4,5,8-naphthoic acid tetrahydrazide; a polyhydrazide obtained by reacting a low polymer having a carboxylic acid lower alkyl ester group with hydrazine or hydrazine hydrate (JP-B-52)
No. 22878).

If the hydrazide compound is too hydrophobic, it may be difficult to disperse it in water and a uniform crosslinked coating film may not be obtained. Therefore, a relatively low molecular weight compound having appropriate hydrophilicity is used. In the above examples, dihydrazides of dicarboxylic acids such as adipic acid dihydrazide and succinic acid dihydrazide are preferable.

Examples of the compound (II-2) having two or more semicarbazide groups per molecule include diisocyanates such as carbonic acid dihydrazide, bissemicarbazide; hexamethylene diisocyanate and isophorone diisocyanate, and polyisocyanate compounds derived therefrom with N. , N-N-substituted hydrazines such as N-dimethylhydrazine and polyfunctional semicarbazides obtained by excessively reacting the above-mentioned hydrazides; hydrophilicity of the polyisocyanate compound with polyether polyols and polyethylene glycol monoalkyl ethers A water-based polyfunctional semicarbazide obtained by excessively reacting the above-exemplified dihydrazide with an isocyanate group in a reaction product with a group-containing active hydrogen compound; of the polyfunctional semicarbazide and the water-based polyfunctional semicarbazide Compound (e.g., JP-A-8-15135
No. 8, JP-A-8-283377, JP-A-8-
245878) and the like.

As the compound (II-3) having two or more hydrazone groups per molecule, for example, bisacetyldihydrazone can be preferably used.

The compounds (II-1) and (II-
2) and (II-3) can be used alone or in combination of two or more. Pigment (III) As the pigment (III) in the composition of the present invention, an ordinary coating pigment can be used, and specifically, for example,
Coloring pigments such as titanium oxide, carbon black and red iron oxide; extender pigments such as calcium carbonate, talc, mica, clay, diatomaceous earth, silica sand and barite; aggregates and the like, and these are used for the purpose of the composition of the present invention. It can be appropriately selected and used according to the above.

In the present invention, the pigment (III) is used in order to prevent the photocuring of the composition of the present invention from being substantially prevented and to maintain a suitable hiding property as a coating composition. , "PVC" may be abbreviated)
Is blended in such a proportion that the content is within the range of 10 to 70%. When the PVC is less than 10%, the hiding of the formed coating film is not sufficient. On the other hand, when the PVC is more than 70%, photocuring of the coating film is suppressed and the initial stage of the coating film immediately after coating in an environment where water evaporation is slow. The water resistance is lowered, and the denseness of the coating film is lowered so that cracks are likely to occur during film formation.

Here, the "pigment volume concentration (PVC)" is a volume ratio of the pigment content in the solid content of the mixture of the resin and the pigment, and is a value calculated by the following formula.

[0052]

[Equation 1]

The above-mentioned PVC is 10 to 60%, preferably 15 to 5% when the composition of the present invention is used in a top coating composition.
Within the range of 5%, and when used in an undercoat paint such as a base adjustment for multi-layer finish, 30 to 70%, preferably 30
It may be in the range of ˜66%. Aqueous coating composition The aqueous coating composition of the present invention contains the above-mentioned copolymer (I), compound (II) and pigment (III) as essential components, and these are dissolved or dispersed in an aqueous medium. It will be.

In the compound (II), the functional group in the compound (III) is generally 0.01 to 2 mol, preferably 0.1 to 1.5 mol per mol of the carbonyl group in the copolymer (I). It can be blended in such a ratio as to fall within the range.

The composition of the present invention may further contain an organosilicate compound, if necessary, in order to further improve the stain resistance of the coating film when it is used in a single-layer finish or multi-layer finish topcoat paint. Can be made. As the organosilicate compound that can be used for such a purpose,
For example, the compound etc. which are represented by a following formula (9) can be mentioned.

[0056]

[Chemical 8]

In the formula, R ¹² is the same or different and is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms.

Examples of the above-mentioned hydrocarbon group include methyl, ethyl, n-propyl, iso-propyl, n-butyl, i-butyl, t-butyl, n-pentyl, iso-pentyl, n-hexyl, i. Alkyl groups such as -hexyl and n-octyl, and aryl groups such as phenyl are preferable.

As specific examples of the organosilicate compound of the above formula (9), for example, tetrahydroxysilane, tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane,
Examples thereof include tetraphenoxysilane and dimethoxydiethoxysilane. These may be used alone or in combination of two or more.

Further, a branched or linear condensate of the above organosilicate compounds can also be used, and the degree of condensation is usually in the range of 2 to 100.

Further, because of its good solubility in water, as the organosilicate compound, a polyalkylene glycol-based compound is added to the alkoxy group or hydroxyl group in the above-mentioned organosilicate compound and / or its condensate. A partially reacted modified organosilicate compound can be particularly preferably used.

Examples of the polyalkylene glycol compound as a modifier include those represented by the following general formula (10). During ^{R 13 O- (R 14 O)} n-H (10) formula, R ¹³ is a hydrogen atom, an alkyl group or an ant - a le radical, R ¹⁴ is an alkylene group having 2 to 4 carbon atoms, n represents Two
-60.

Specific examples of such a compound include:
For example, polyalkylene glycol such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol; methoxypolyethylene glycol,
Alkoxy polyalkylene glycols such as ethoxy polyethylene glycol, ethoxy polypropylene glycol and ethoxy polybutylene glycol; polyoxyalkylene alkyls such as polyoxyethylene nonylphenyl ether and polyoxyethylene octylphenyl ether. Examples thereof include phenyl ether, and particularly polyethylene glycol and polyoxyethylene nonylphenyl ether.
Tell is preferred.

The content of the above organosilicate compound in the composition of the present invention is such that the resin solid content in the coating composition is 10%.
It can be generally in the range of 0.1 to 50 parts by weight, preferably 1 to 20 parts by weight, per 0 parts by weight.

In the aqueous coating composition of the present invention, alkylene glycol di (meth) acrylate, polyalkylene glycol poly (meth) acrylate, urethane ( A compound having two or more (meth) acryloyl groups such as (meth) acrylate and polyester (meth) acrylate may be included.

If necessary, a surfactant,
A dispersant, a defoaming agent, a thickening agent, a film-forming auxiliary agent, an antiseptic agent, an antifreezing agent and the like can be added.

The water-based coating composition of the present invention is easily cured at room temperature and is further accelerated by irradiation with natural light. Therefore, it is particularly suitable for coating the interior and exterior of buildings, bridges, ships, etc. Suitable for paint applications. In addition, it can be used as a single-layer top coat paint because it forms a coating film with excellent performance even with a single-layer finish, but it is also used as a top coat paint for multi-layer finish or as an undercoat paint for undercoat adjustment. be able to.

The composition of the present invention can be applied to the surface of a base material, the surface of an undercoat, or the surface of an old coating film. The base material is not particularly limited, and examples thereof include concrete surface,
Mortar surface, slate plate, PC plate, ALC plate, cement calcium silicate plate, concrete block surface, wood, stone material, plastic, metal, etc. can be mentioned. Examples of the acrylic resin-based, acrylic urethane resin-based, polyurethane resin-based, fluororesin-based, silicon acrylic resin-based, vinyl acetate resin-based, epoxy resin-based coating film surfaces that have been obtained.

The coating amount of the aqueous coating composition of the present invention is usually 0.3 to 1.5 kg / when used for a single layer finish.
m ^2, preferably is suitable in the range of 0.4~1.0kg / m ^2, when used as a topcoat, typically 0.06~0.20kg / m ^2, preferably 0.8
In the range of 1.6 kg / m ^2, and when used in the undercoat application is usually 0.3~2.0kg / m ^2, preferably suitably in the range of 0.5~1.5kg / m ² is there.

The coating can be carried out using a known coating device such as a roller, an air sprayer, an airless sprayer, a resin gun, a universal gun or a brush.

[0071]

EXAMPLES The present invention will be described in more detail below with reference to examples. In addition, "part" means a weight part.

A copolymer having a maleimide group and a carbonyl group
Production of Polymer Production Example 1 Imide acrylate represented by the following formula (11) (hereinafter,
10 parts of imide acrylate), 5 parts of diacetone acrylamide, 50 parts of n-butyl methacrylate
Parts, 20 parts of methyl methacrylate, 14 parts of n-butyl acrylate and 1 part of methacrylic acid are mixed, and 100 parts of deionized water and 0.5 parts of "Aqualon HS10" (Note 1) are added to the mixture, and the mixture is rotated. A monomer emulsion was prepared using a homomixer.

[0073]

[Chemical 9]

On the other hand, 45 parts of deionized water, "Aqualon H
After replacing the inside of the flask containing 0.5 parts of S10 "(Note 1) with nitrogen, heat the temperature to 80 ° C, and heat the internal liquid to a temperature of 80 ° C.
While maintaining the above, 1 part of ammonium persulfate and 2% by weight of the above monomer emulsion are added thereto, and 15 minutes after the addition, the remaining monomer emulsion is added dropwise over 2 hours, and further 2 Aged for hours. After aging, the mixture was cooled and 3 parts of 10 wt% ammonia water was added dropwise as a neutralizing agent to obtain an emulsion type copolymer aqueous dispersion (A-1). (Note 1) "Aqualon HS10": manufactured by Dai-ichi Kogyo Co., Ltd.
Radical-polymerizable surfactant represented by the following formula (12)

[0075]

[Chemical 10]

Production Example 2 and Production Examples 4 to 6 An aqueous copolymer dispersion (A-2 was prepared in the same manner as in Production Example 1 except that the composition of the monomer emulsion used was as shown in Table 1 below. ), And copolymer aqueous dispersion (A-4)
~ (A-6) were obtained. Production Example 3 “Aqualon HS10” (Note 1) Instead of 0.5 parts each, “N
ewcol707SF ”(Note 2) was used in the same manner as in Production Example 1 except that 1 part each was used.
3) was obtained. (Note 2) "Newcol 707SF": manufactured by Nippon Emulsifier Co., Ltd., an anionic surfactant having a polyoxyethylene chain, non-volatile content 30%

[0077]

[Table 1]

Production of Modified Organosilicate Production Example 7 In a reaction vessel equipped with a stirrer, a thermometer, a reflux tube, a nitrogen inlet tube and a water separator, "ethyl silicate 48" (Note 3) 5
00 parts, "Newcol 568" (Note 4) 324.5 parts and "Scat 24" (Note 5) 0.082 parts were charged, and the temperature was raised to 120 ° C with stirring in a nitrogen atmosphere, and then to 160 ° C over 4 hours. The temperature was raised and the temperature was maintained for 1 hour. At that time, 25 parts of ethanol and the like which was evaporated was distilled off in a water separator to obtain 800 parts of modified organosilicate. (Note 3) "Ethyl silicate 48": Tama Chemical Co., Ltd., condensation product of ethyl silicate (Note 4) "Newcol 568": Nippon Emulsifier, polyoxyethylene nonylphenyl ether (Note 5) "Scat 24" Manufacture of a tin-based catalyst premix paint manufactured by Sankyo Machine Gosei Co., Ltd. Production Examples 8 to 15 Each component shown in composition A of Table 2 below is sequentially charged into a container,
Stirring was continued for 30 minutes with a disperser until uniform, and a pigment paste was obtained. Then, each component shown in Composition B of Table 2 was sequentially added to the pigment paste and stirred with a disperser until uniform, and premix paints (P-1) to (P-4)
And (Q-1) to (Q-4) were obtained.

[0079]

[Table 2]

(Note 6) "Slaoff 72N": manufactured by Takeda Pharmaceutical Co., Ltd.
Preservative (Note 7) "Nopco Santo K": San Nopco, pigment dispersant (Note 8) "Titanium white JR805": Teika titanium white (Note 9) "Titanium white JR800": Teika titanium white (Note 10) "SN deformer A-63": manufactured by San Nopco, defoamer (Note 11) "Adecanol UH-438": manufactured by Adeka
Thickener (Note 12) "SN deformer 380": manufactured by San Nopco, defoamer topcoat paint preparation Examples 1-7 and Comparative Examples 1-4 Obtained in Production Examples 8-15 with the combinations shown in Table 3 below. A cross-linking agent was added to 100 parts of each premix paint to obtain each topcoat paint.

Preparation of Test Plate for Topcoat Paint "Multiconcrete Primer EPO" (Kansai Paint Co., Ltd., epoxy-based primer) was applied to a slate plate of 70 × 150 × 5 mm, and on the next day, each topcoat paint shown in Table 3 below was applied. After diluting to about 70 KU with tap water, coating was applied with a brush so that the applied amount was about 0.15 kg / m ² .

Each top coating composition and each test plate were evaluated according to the criteria described below, and the results are shown in Table 3.

[0083]

[Table 3]

(Note 13) "SX-601": Asahi Kasei Corporation, semicarbazide functional group-containing compound, solid content 45
%, - NHCO-NHNH ₂ content 4.8 mmol /
g Resin (Note 14) 20% Bisacetyldihydrazone: Methyl ethyl ketone solution Preparation of undercoat paint Examples 9 to 12 and Comparative Examples 4 to 6 Premix paints 100 obtained in Production Examples 8 to 15 in the combinations shown in Table 4 below. A cross-linking agent was added to each part to obtain each undercoat paint.

Preparation of test plate for undercoat paint "EP sealer transparent" (Kansai Paint Co., Ltd., water-based sealer) was applied to a slate plate of 70 × 150 × 5 mm, and each undercoat paint shown in Table 4 below was applied by a clavicle roller. The coating amount was about 0.8 Kg / m ² .

Each undercoat paint and each test plate were evaluated according to the criteria described below, and the results are shown in Table 4.

[0087]

[Table 4]

Evaluation test Paint storage stability test Each of the topcoat paints and undercoat paints obtained above was stored in a thermostatic chamber at 50 ° C for one month, and the state of the paints was visually evaluated.

⊚: Good, almost the same as the initial stage.

◯: Although the viscosity is slightly increased, there is no problem in practical use.

Δ: Thickening is remarkable and not practical, but gelation has not been achieved.

X: Gelled.

Initial water resistance test (outdoor) Each test coated plate coated with each of the above-prepared topcoat and bottomcoat paint was placed in a cold greenhouse at 5 ° C. for 30 minutes immediately after coating, and then exposed outdoors on a cloudy day ( It was left in the shade on the north side of the building for about 1 hour (temperature: 8-10 ° C, 65-75% RH)
Conditions). Then, each test plate was submerged in water for 10 minutes, and the appearance of the coating film was visually evaluated.

⊚: The coating film is good with no abnormality.

◯: Slight glossiness or blistering is observed, but there is no problem in practical use.

Δ: Large or large blisters or partial elution of coating film is observed.

X: The coating film is significantly eluted.

Initial Water Resistance Test (Indoor) Each test coated plate coated with each of the above-mentioned topcoat paint and undercoat paint was placed in a cold greenhouse at 10 ° C. for 30 minutes immediately after coating, and was not exposed to direct sunlight but natural light. It was left for about 1 hour in a bright room containing (at 20 ° C. and 60 to 70% RH). Then, each test coated plate was submerged in water for 10 minutes, and the appearance of the coating film was visually evaluated.

⊚: The coating film is good with no abnormality.

◯: Slight glossiness or blistering is observed, but there is no problem in practical use.

Δ: Large or large blisters or partial elution of coating film is observed.

X: Elution of the coating film is remarkable.

Outdoor Contamination Test (Topcoat) A primer was coated on a slate plate of 90 × 300 × 5 mm in the same manner as the above test plate for topcoat, and each topcoat was coated on the next day in the same manner. The test coated plate was prepared by coating, recoating, and drying at room temperature for 7 days. One of them was used for exposure and the other was reserved. The test coated plate for exposure was attached to the exposed plate of 30 degrees on the south side in the Kansai Paint Tokyo Works, and taken out after 3 months, and the color difference ΔE with the reserve test plate was measured. The smaller the value, the better.

[0104]

The aqueous coating composition of the present invention is easily cured at room temperature due to the reaction between the carbonyl group contained in the copolymer and the crosslinking agent. Furthermore, even if the coating drying conditions are such that the evaporation of water is slow (for example, cloudy, low temperature, indoors),
Within the range where light rays such as ultraviolet rays can reach, photocuring by the maleimide group proceeds, so that the physical properties of the coating film such as water resistance and stain resistance can be improved even in the initial stage after coating.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masami Sugishima             Seki, 4-17-1, Higashi-Hachiman, Hiratsuka City, Kanagawa Prefecture             West Paint Co., Ltd. (72) Inventor Nakamura Hoki             Seki, 4-17-1, Higashi-Hachiman, Hiratsuka City, Kanagawa Prefecture             West Paint Co., Ltd. (72) Inventor Mitsuhase Hasegawa             1 East of Funami-cho, Minato-ku, Nagoya City, Aichi Prefecture             Inside of Polymer Materials Research Laboratories (72) Inventor Hiroshi Inukai             1 East of Funami-cho, Minato-ku, Nagoya City, Aichi Prefecture             Inside of Polymer Materials Research Laboratories F-term (reference) 4J038 CC011 CF011 CG131 CG191                       CH011 CH071 CH191 CL001                       CR061 DL022 GA02 GA09                       JB17 KA03 KA08 KA09 MA08                       MA10 NA01 PA17 PB05 PB07                       PC04 PC06 PC08

Claims (3)

[Claims] 1. A copolymerization of an ethylenically unsaturated monomer (a) having a maleimide group, an ethylenically unsaturated monomer (b) having a carbonyl group and another ethylenically unsaturated monomer (c). A copolymer (I) obtained by: a hydrazide group,
Compound (II) having two or more same or different functional groups selected from semicarbazide group and hydrazone group per molecule; and pigment (III), and the pigment volume concentration is within the range of 10 to 70% An aqueous coating composition characterized by: 2. The copolymer (I) is a monomer (a),
1 to 40% by weight of an ethylenically unsaturated monomer (a) having a maleimide group, based on the total amount of (b) and (c)
And 1 to 30% by weight of a carbonyl group-containing ethylenically unsaturated monomer (b) and 40 to 98% by weight of another ethylenically unsaturated monomer (c) are obtained by emulsion polymerization. The water-based coating composition according to claim 1. 3. A modified organosilicate obtained by reacting an organosilicate and / or a condensate thereof with 0.001 to 0.5 mol of a polyalkylene glycol compound per 1 mol of the alkoxy group or hydroxyl group. The water-based coating composition according to claim 1 or 2, further comprising a tomato compound.