JPH11124533A - Aqueous coating composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an aqueous coating composition which forms a film showing water repellency and waterproofness by mixing a water dispersion of (meth) acrylate-based copolymer by emulsion polymerization, a water solution and/or a water dispersion of a copolymer of polysiloxane chain-containing and/or fluorine-containing monomers and a hydrazine derivative. SOLUTION: An aqueous coating composition comprises a water dispersion of an emulsified copolymer of a mixture of 50-98 wt.% (meth)acrylate having not less than 4 carbon atoms and 2-10 wt.% carbonyl group-containing monomer, a water solution and/or a water dispersion of a copolymer of a mixture of 3-70 wt.% monomers represented by formula I (wherein R<1> is hydrogen or methyl; R<2> includes phenyl and a 1-6C alkyl; n<1> is 1-10; and n<2> is 5-200) and/or formula II (wherein R<3> is hydrogen or methyl; X is hydrogen or fluorine; n<3> is 1-8; and n<4> is 1-30), 1-40 wt.% alkoxysilyl-containing monomer and 1-25 wt.% polymerizable monomer containing a carboxyl group, a sulfonyl group or an amino group and a hydrazine derivative having not less than 2 of -NH-NH2 .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-based paint composition for forming a waterproof coating film on a roof or an outer wall of a building, and more particularly to a water-repellent composition without deteriorating weather resistance, stain resistance and initial drying property. And a water-based coating composition capable of forming a highly waterproof coating film.

[0002]

2. Description of the Related Art When a new construction is applied to a roof or an outer wall of a building, or when repainting is applied, a top coat is used to prevent rainwater from entering through cracks on the outer wall and gaps between the roof tiles. In view of prevention of contamination and safety at the time of painting, an aqueous paint capable of forming a coating film excellent in weather resistance, water repellency, and waterproofness is required.

[0003] Conventional water-based paints mainly use an acrylic copolymer emulsion as a vehicle component, and require the fusion of emulsion particles during the film formation process. And water resistance were insufficient. On the other hand, the applicant of the present invention has proposed that the emulsion particles be crosslinked with a crosslinking agent having a relatively small molecular weight (Japanese Patent Laid-Open No. 249587/1992). In addition, weather resistance and initial drying properties were also ensured. However, in this water-based paint,
Because of the high hydrophilicity of the carbonyl group, which is a cross-linking group in the coating, improvement in water repellency and waterproofness could not be expected.

[0004] On the other hand, a method of imparting water repellency to a dried coating film by mixing a low molecular weight water repellent such as polydimethylsiloxane into a coating material has been well known. In addition, there were problems such as poor water-repellency, no film formation, reduced water repellency over time after film formation, and insufficient waterproofness.

As a solution to this, for example, Japanese Patent Laid-Open No.
No. 0475 discloses a method for imparting waterproofness and water repellency by using a resin obtained by emulsion polymerization of an organopolysiloxane macromonomer and another unsaturated monomer. However, in this method, a large amount of surfactant must be used, and the resin becomes cloudy. In order to prevent such clouding, for example, JP-A-6-25369 proposes a resin obtained by polymerizing without using a surfactant. There were problems such as the solid content concentration being too low.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above problems, and as a result, it has been found that a water-based paint having a specific composition can provide water repellency without deteriorating weather resistance, stain resistance and initial drying property. The present inventors have found that a water-resistant coating film can be formed, and have reached the present invention.

That is, the present invention relates to (A)
50 to 98% by weight of the above (meth) acrylic acid ester having an alkyl group, (b) a carbonyl group-containing monomer
And (c) a copolymer aqueous dispersion obtained by emulsion polymerization of a monomer mixture containing 2 to 10% by weight of (c) and 0 to 48% by weight of another polymerizable unsaturated monomer. 3 to 70% by weight of at least one monomer selected from monomers represented by structural formulas (I) and (II),

[0008]

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(Wherein R ¹ represents a hydrogen atom or a methyl group;
The R ² may be the same or different phenyl group or an alkyl group having 1 to 6 carbon atoms, n ₁ is 1 to 10 integer, n ² is 5-2
00 indicates an integer. )

[0010]

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(Wherein, R ³ represents a hydrogen atom or a methyl group;
X a is a hydrogen atom or a fluorine atom, n ³ is an integer of 1 to 8, n ⁴ represents respectively an integer of 1 to 30. And (f) 1 to 40% by weight of an alkoxysilyl group-containing monomer, and (f) 1 to 4 polymerizable unsaturated monomers having one kind of functional group selected from the group consisting of a carboxyl group, a sulfonic acid group and an amino group.
25% by weight, and (g) a copolymer aqueous solution or aqueous dispersion obtained by copolymerizing a monomer mixture containing 0 to 95% by weight of another polymerizable unsaturated monomer; and (C) at least one molecule per molecule. It is intended to provide an aqueous coating composition comprising a hydrazine derivative having _two -NH-NH2-containing groups.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a copolymer aqueous dispersion (A) contains (a) a (meth) acrylate having an alkyl group having 4 or more carbon atoms in an amount of 50 to 98% by weight,
An aqueous copolymer dispersion obtained by emulsion polymerization of a monomer mixture containing (b) a carbonyl group-containing monomer at 2 to 10% by weight and (c) another polymerizable unsaturated monomer at 0 to 48% by weight. is there.

Examples of the (meth) acrylate (a) having an alkyl group having 4 or more carbon atoms include n-, i-, t-butyl (meth) acrylate and (meth) acrylate.
Hexyl acrylate, octyl (meth) acrylate,
2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, cyclohexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, isobornyl (meth) acrylate Examples thereof include alkyl or cycloalkyl esters of (meth) acrylic acid having 4 or more carbon atoms, preferably 4 to 10 carbon atoms, and these can be used alone or in combination of two or more.

Examples of the carbonyl group-containing monomer (b) include acrolein, diacetone acrylamide, diacetone methacrylamide, acetoacetoxyethyl methacrylate, formyl styrene and vinyl alkyl having 4 to 7 carbon atoms. Ketones (for example, vinyl methyl ketone, vinyl ethyl ketone, vinyl butyl ketone) and the like can be mentioned. Of these, diacetone acrylamide and diacetone methacrylamide are particularly preferred.

Other polymerizable unsaturated monomers (c) include, for example, vinyl aromatic compounds such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, styrene and vinyltoluene; Examples thereof include N-vinylpyrrolidone, ethylene, butadiene, chloroprene, vinyl propionate, vinyl acetate, (meth) acrylonitrile, and the like, which are appropriately used depending on desired performance.

As other polymerizable unsaturated monomers, monomers having an acid group or a hydroxyl group, which is a hydrophilic group, can also be used, and may be used within a range that does not adversely affect the water permeability of the coating film. desirable. Examples of such a monomer having a hydrophilic group include (meth) acrylic acid, maleic acid, crotonic acid, β-carboxyethyl acrylate
, 2-acrylamido-2-methylpropanesulfonic acid, allylsulfonic acid, styrenesulfonic acid sodium salt, sulfoethyl methacrylate and its sodium and ammonium salts, etc .; (meth) acrylamide, dimethylaminopropyl (meth) acrylamide Dimethylaminoethyl (meth) acrylate, and adducts of glycidyl (meth) acrylate and amines; and non-hydroxy compounds such as (meth) acrylate having a polyoxyethylene chain, such as 2-hydroxyethyl (meth) acrylate. ) Acryle
And hydroxyalkyl (meth) acrylic acid having 2 to 8 carbon atoms such as hydroxypropyl (meth) acrylate.

The proportion of the monomer mixture used is (a)
Is 50 to 98% by weight, preferably 60 to 93% by weight,
(B) 2-10% by weight, preferably 2-8% by weight, and (c) 0-48% by weight, preferably 5-32% by weight. When the use ratio of (a) is less than 50% by weight, the water permeability of the obtained coating film increases, while when it exceeds 98% by weight,
It is not preferable because the stability of the emulsion decreases. When (b) is less than 2% by weight, the resulting coating film has water resistance,
If the weather resistance and the initial drying property are reduced, on the other hand, if it exceeds 10% by weight, the hydrophilicity of the coating film increases and the water permeability increases, which is not preferable.

In the above monomer mixture, a polyvinyl compound having at least two or more polymerizable unsaturated groups in one molecule is required in view of water resistance and curability of the coating film at the initial stage of drying. 0.05 to 5% by weight, preferably 0.
1 to 4% by weight can be contained.

The polyvinyl compound may be a polyvalent alcohol.
Polymerizable unsaturated monocarboxylic acid esters, polybasic acid-polymerizable unsaturated alcohol esters, and aromatic compounds substituted with two or more vinyl groups, and the like, for example, ethylene glycol di (meth) acrylate , Trimethylolpropane tri (meth) acrylate, 1,4-butanediol di (meth) acrylate, neopentylglycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate 1,1,1-trishydroxymethylethanedi (meth) acrylate, 1,1,
Examples thereof include 1-trishydroxymethylpropane tri (meth) acrylate, triallyl isocyanurate, diallyl terephthalate, and divinylbenzene.

The above monomer mixture may contain a polysiloxane group-containing monomer represented by the following structural formula (III) in an amount of 0.5 to 20% by weight, if necessary, preferably from the viewpoint of improving waterproofness. 0.5 to 10% by weight can be contained.

[0021]

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(Wherein R ⁴ represents a hydrogen atom or a methyl group;
R ⁵ is an aliphatic saturated hydrocarbon group having 1 to 10 carbon atoms, R ⁶
In the same or different alkyl group or a phenyl group having 1 to 6 carbon atoms, n ⁵ is an integer of 5 to 200) the structural formula (III), an aliphatic having 1 to 10 carbon atoms represented by R ⁵ As the saturated hydrocarbon group, a linear or branched alkylene group, for example, methylene, ethylene,
Propylene, tetramethylene, pentamethylene groups and the like can be mentioned. The polysiloxane group-containing monomer
Preferably, the number average molecular weight is from 500 to 15,000.

The copolymer aqueous dispersion (A) can be easily obtained, for example, by subjecting the monomer mixture to emulsion polymerization in the presence of an emulsifier. Examples of the emulsifier include an anionic surfactant, a nonionic surfactant, and a reactive emulsifier. Emulsion polymerization can be carried out using a polymerization initiator in the presence of one or more of the emulsifiers.

The aqueous copolymer dispersion (A) may be of a core / shell type. In this case, first, the monomer mixture forming the core component is subjected to the first stage of emulsion polymerization using a polymerization initiator in the presence of an emulsifier to obtain a copolymer aqueous dispersion. The monomer mixture forming a shell component is subjected to a second stage of emulsion polymerization using a polymerization initiator to obtain an aqueous dispersion of core-shell particles. The composition of the monomer mixture forming the core and the shell and the weight ratio of the core / shell can be appropriately selected without particular limitation as long as the usage ratio of the entire monomer is within the above range.

The acid value of the aqueous copolymer dispersion (A) is 1
Suitably, it is from 10 to 10. When the acid value exceeds 10, the hydrophilicity of the resulting coating film increases and the amount of water permeation increases, which is not preferable. The resin Tg of the aqueous copolymer dispersion (A) is -30 to 80C, preferably -20 to 50C.
Is suitably within the range. If the resin Tg is lower than −30 ° C., the water permeability of the resulting coating film is increased, and if it is higher than 80 ° C., it is not preferable because it cannot follow the substrate and is easily cracked.

In the present invention, the aqueous copolymer solution or the aqueous dispersion (B) is (d) one of the above structural formulas (I) and (I)
3 to 70% by weight of at least one monomer selected from the monomers represented by I), (e) 1 to 40% by weight of an alkoxysilyl group-containing monomer, (f) carboxyl group, sulfonic acid group and amino group 1 to 25% by weight of a polymerizable unsaturated monomer having one type of functional group selected from the group of groups, and (g) 0 to 25% of other polymerizable unsaturated monomers.
It is a copolymer aqueous solution or aqueous dispersion obtained by copolymerizing a mixture containing 95% by weight.

At least one monomer (d) selected from the monomers represented by the structural formulas (I) and (II)
Is for imparting water repellency to the copolymer, and is a monomer having a polysiloxane chain represented by the above structural formula (I).
Any one or both of the fluorine-containing monomer (d-2) represented by (d-1) and the structural formula (II) can be used.

The monomer (d) represented by the above structural formula (I)
In -1), R ¹ is a hydrogen atom or a methyl group, and R ² is a phenyl group or an alkyl group having 1 to 6 carbon atoms, but they are not necessarily the same.
n1 is an integer of ¹ to 10, and n2 is an integer of 5 to ²⁰⁰ , preferably 15 to 150. If n ² is less than 5, sufficient water repellency cannot be obtained, while if it exceeds 200, the copolymer becomes insufficient in hydrophilicity and poor in water solubility or water dispersibility, which is not desirable. As a specific example of the monomer (d-1), commercially available products include "Silaplane FM-0711",
"Silaplane FM-0721", "Silaplane FM-0725" (all manufactured by Chisso Corporation) and the like.

The monomer (d) represented by the above structural formula (II)
In -2), R ³ is a hydrogen atom or a methyl group, and X is a hydrogen atom or a fluorine atom. n ³ is 1
An integer of 8 and n ⁴ is an integer of 1 to 30. When n ⁴ exceeds 30, poor mixing properties and copolymerizability with other monomers, also undesirable because the water-soluble or water-dispersible poor due to the lack of hydrophilicity. Specific examples of the monomer (d-2) include, for example, 2,2,2-trifluoroethyl (meth) acrylate, 2,2,3,3-tetrafluoropropyl (meth) acrylate, 2- (pentadecafluoro Commercially available products such as octyl) ethyl (meth) acrylate and 2- (nonadecafluorodecyl) ethyl (meth) acrylate are “FAMAC” (manufactured by Nippon Mektron), “Viscoat 8FM”, and “Viscoat 17FM”.
(Both manufactured by Osaka Organic Chemical Industry Co., Ltd.).

Alkoxysilyl group-containing monomer (e)
Has an alkoxysilyl group represented by the following structural formula (IV),

[0031]

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Wherein R ⁷ is an alkyl group having 1 to 10 carbon atoms, and R ⁸ and R ⁹ are the same or different and each represents a phenyl group, an alkyl group having 1 to 6 carbon atoms or an alkoxyl group having 1 to 10 carbon atoms. , N ⁶ each represent an integer of 1 to 4. When n ⁶ is 2 or more, R ⁸ and R ⁹ may be the same or different from each other.) Typical examples thereof are as follows. Examples include monomers represented by structural formulas (V) and (VI).

[0033]

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(Where A is

[0035]

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Is shown. R ¹⁰ represents a hydrogen atom or a methyl group,
R ¹¹ represents a divalent saturated aliphatic hydrocarbon group having 1 to 6 carbon atoms. R ⁷ , R ⁸ , R ⁹ and n ⁶ each have the same meaning as described above. )

[0037]

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(Wherein, R ¹² represents a divalent aliphatic saturated hydrocarbon group having 1 to 6 carbon atoms, and n ⁷ represents 0 or 1. R ⁷ , R ^7
8 , R ⁹ and n ⁶ each have the same meaning as described above. In the structural formulas (V) and (VI), as the divalent saturated aliphatic hydrocarbon group having 1 to 6 carbon atoms represented by R ¹¹ and R ¹² , a linear or branched alkylene group, for example, Methylene, ethylene, propylene, 1,2-, 1,3-
Or 2,3-butylene, tetramethylene, ethylethylene, pentamethylene, hexamethylene groups and the like. As the alkyl group having 1 to 6 carbon atoms represented by R ⁸ and R ⁹ , a linear or branched alkyl group, for example, methyl, ethyl, n-propyl, isopropyl, n-, i
-, Sec- or tert-butyl, n-pentyl, isopentyl, neopentyl, n-hexyl, isohexyl, 1-methylpentyl and the like. Examples of the alkyl group having 1 to 10 carbon atoms represented by R ⁷ include R ⁸ and R
^In addition to those exemplified as the alkyl group having 1 to 6 carbon atoms represented by ⁹ , n-heptyl, 2-ethylhexyl, n-octyl, n-nonyl, n-decyl and the like are further exemplified. As the alkoxyl group having 1 to 10 carbon atoms represented by R ⁸ and R ⁹ , a linear or branched alkoxyl group, for example, methoxy, ethoxy, n-propoxy, isopropoxy, n-, i-, sec- or tert-butoxy, n-pentoxy, isopentoxy, n-hexyloxy, isohexyloxy, n-octyloxy and the like.

In the monomer of the above structural formula (V), A is

[0040]

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For example, β- (meta)
Acryloyloxyethoxysilane, γ- (meth) acryloyloxypropyltrimethoxysilane, γ- (meth) acryloyloxypropyltriethoxysilane,
γ- (meth) acryloyloxypropylmethyldimethoxysilane, γ- (meth) acryloyloxypropylmethyldiethoxysilane and the like can be preferably exemplified.

In the monomer of the above structural formula (V), A is

[0043]

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For example,

[0045]

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And the like.

Examples of the monomer of the structural formula (VI) include vinyltrimethoxysilane and vinyltriethoxysilane.

The polymerizable unsaturated monomer (f) having one kind of functional group selected from the group consisting of a carboxyl group, a sulfonic acid group and an amino group improves the water solubility or water dispersibility of the copolymer. Examples of the monomer having a carboxyl group include (meth) acrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, 2-carboxyethyl (meth) acrylate, 2-carboxylpropyl (meth) acrylate, and 5- Carboxylpentyl (meth) acrylate, an equimolar addition product of an unsaturated monomer having a hydroxyl group and a bifunctional carboxylic anhydride (eg, maleic anhydride, itaconic anhydride, succinic anhydride, phthalic anhydride, etc.). Examples of the monomer having a sulfonic acid group include 2- (meth) acryloxyethylsulfonic acid. It is. Examples of monomers having an amino group include dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, and t-butylaminoethyl (meth) acrylate.

Other polymerizable unsaturated monomers (g) include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate,
Isopropyl (meth) acrylate, (meth) acrylic acid
n-butyl, i-butyl (meth) acrylate, t-butyl (meth) acrylate, hexyl (meth) acrylate,
2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, decyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, (meth) acryl Isobornyl acrylate, methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, methoxybutyl (meth) acrylate, ethoxybutyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, (meth) acrylic acid 2-hydroxypropyl, 3-hydroxypropyl (meth) acrylate, 4- (meth) acrylate
(Meth) acrylic acid esters such as hydroxybutyl, polyether polyols such as polyethylene glycol and polypropylene glycol and (meth) acrylic acid; ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, t Vinyl ethers such as butyl vinyl ether, hexyl vinyl ether, octyl vinyl ether, cyclohexyl vinyl ether and phenyl vinyl ether; vinyl acetate, vinyl propionate,
Vinyl esters such as vinyl lactate, vinyl butyrate, and vinyl caproate; propenyl esters such as isopropenyl acetate, (meth) acrylonitrile, styrene, α-methylstyrene, vinyltoluene, and α-chlorostyrene. The species or two or more species can be appropriately selected and used according to the purpose.

The proportion of the monomer mixture used is (d)
From 3 to 70% by weight, preferably from 5 to 40% by weight, (e)
From 1 to 40% by weight, preferably from 3 to 20% by weight, (f)
1 to 25% by weight, preferably 5 to 15% by weight, and (g) 0 to 95% by weight, preferably 20 to 70% by weight.
It is. If (d) is less than 3% by weight, sufficient water repellency cannot be obtained, while if it exceeds 70% by weight, it becomes difficult to make the copolymer water-soluble or water-dispersible. (E)
If the content is less than 1% by weight, the water solubility or water dispersibility of the copolymer aqueous solution (water dispersion) becomes poor, and if it exceeds 40% by weight, the copolymer polymerization process or the water-solubilizing / water dispersing process results. Hydrolysis of the alkoxysilyl group and self-condensation reaction tend to cause gelation, which is not preferable. If (f) is less than 1% by weight, it is difficult to make the copolymer water-soluble or water-dispersible. Conversely, if it exceeds 25% by weight, sufficient water repellency cannot be obtained, and furthermore the water resistance is remarkably reduced. Not preferred.

Further, the monomer mixture may contain a carbonyl group-containing monomer (h) in an amount of 1 to 10% by weight, preferably 2 to 8% by weight, if necessary, from the viewpoint of water resistance and the like. . As the carbonyl group-containing monomer (h), those listed in the description of the carbonyl group-containing monomer (b) in the aqueous copolymer dispersion (A) can be similarly exemplified, and can be appropriately selected and used.

The aqueous copolymer solution or aqueous dispersion (B) can be prepared by subjecting the monomer mixture to a water-soluble or water-dispersible method using a neutralizing agent after solution polymerization, or an emulsion polymerization method using a surfactant. It can be manufactured by such a method. In particular, from the viewpoint of water repellency and water resistance of the obtained coating film, the method described in the above, that is, after obtaining a copolymer solution by performing radical polymerization of the above monomer mixture in the presence of a polymerization initiator in an organic solvent, It is preferable to add water and a neutralizing agent to make the mixture water-soluble or dispersed in water.

In the above method, as the organic solvent used in the radical polymerization, alcohols, cellosolves, carbitols, cellosolve acetates and the like can be used. It is desirable that the alcohol of No. 8 is contained in an amount of 10% by weight or more, preferably 30% by weight or more. Examples of the radical polymerization initiator include azo-based polymerization initiators such as 2,2-azobisisobutyronitrile and 2,2-azobis (2,4-dimethylvaleronitrile), or lauryl peroxide, t-butyl per 2 -Peroxide initiators such as ethylhexanate and benzoyl peroxide can be used.

In the above method, the neutralizing agent used for water-solubilization or water-dispersion is a monomer.
When (f) has a carboxyl group or a sulfonic acid group, for example, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, monobutylamine, dibutylamine, tributylamine Amines such as butylamine, monoethanolamine, diethanolamine, triethanolamine, dimethylaminoethanol, diethylaminoethanol, ammonia, sodium hydroxide,
Potassium hydroxide and the like can be used, and when the monomer (f) has an amino group, for example, inorganic acids such as hydrochloric acid, sulfuric acid and phosphoric acid, formic acid, acetic acid, propionic acid, trimethylacetic acid, (meth) acrylic Organic acids such as acid and lactic acid can be used.

When the copolymer obtained by the radical polymerization is solubilized or dispersed in water, water is added to the copolymer solution and then a neutralizing agent is added in order to prevent thickening and gelation. It is preferred to add.

In the present invention, the use ratio of the copolymer solutions (A) and (B) obtained as described above is (A) and (B)
Has a solid content ratio of 70/30 to 99/1, preferably 8
It is preferable to mix them in the range of 5/15 to 98/2. If the use ratio of (A) is less than this range, the waterproofness becomes insufficient, and if it is too large, the effect of water repellency decreases, which is not preferable.

In the present invention, at least 2
Hydrazine derivative having the number of -NH-NH ₂ containing group (C) is a crosslinking agent component, where the -NH-NH ₂ containing group, hydrazide group, include semicarbazide group.

Examples of the hydrazine derivative (C) include saturated aliphatic carboxylic acids having 2 to 18 carbon atoms such as oxalic acid dihydrazide, malonic acid dihydrazide, glutaric acid dihydrazide, succinic acid dihydrazide, adipic acid dihydrazide and sebacic acid dihydrazide. Acid dihydrazide;
Monoolefinically unsaturated dicarboxylic acid dihydrazides such as maleic dihydrazide, fumaric acid dihydrazide, itaconic acid dihydrazide; phthalic acid, terephthalic acid or isophthalic acid dihydrazide; and dihydrazide, trihydrazide or tetrahydrazide of pyromellitic acid;
Nitrilotrihydrazide, citric acid trihydrazide,
1,2,4-benzenetrihydrazide, ethylenediaminetetraacetic acid tetrahydrazide, 1,4,5,8-naphthoic acid tetrahydrazide, and a low polymer having a lower alkyl ester group of carboxylic acid are converted to hydrazine or hydrazine hydrate (hydrazine hydrazide). Polyhydrazide (see Japanese Patent Publication No. 52-22878); dihydrazide carbonate, bissemicarbazide; diisocyanates such as hexamethylene diisocyanate and isophorone diisocyanate and derivatives derived therefrom. Polyfunctional semicarbazide obtained by excessively reacting a hydrazine compound or the above-mentioned dihydrazide with a polyisocyanate compound, and hydrophilicity such as polyisocyanate compound and polyetherpolyols or polyethylene glycol monoalkyl ethers. Group containing activity Aqueous polyfunctional semicarbazide obtained by excessively reacting the above-mentioned dihydrazide with an isocyanate group in a reaction product with an elemental compound, or a mixture of the polyfunctional semicarbazide and an aqueous polyfunctional semicarbazide (JP-A-8-151358) And JP-A-8-245878).

The hydrazine derivative (C) has one of the carbonyl groups contained in the copolymer aqueous dispersions (A) and (B).
-NH-NH in the hydrazine derivative (C) based on the mole
₂ containing group is 0.01 to ₂ mol, preferably 0.05 to 2
It is blended to be 1.5 mol.

The aqueous coating composition of the present invention comprises the above (A)
A thickener (D) which contains the components (B) and (C) and further improves storage stability and coating workability.
Can be included.

As the thickener (D), any of an organic type and an inorganic type can be used. In particular, those which are water-soluble and have a moderately hydrophobic portion are suitable. For example, methylcellulose,
Ethyl cellulose, polyvinyl alcohol, casein,
Tragacanth rubber, barium rubber, cellulose acetate phthalate, bentonite, hydroxycellulose
, Polymethacrylic acid, gum arabic, gum karaya, gelatin, sodium alginate, albumin, pectin, xanthan gum and the like.

The amount of the thickener (D) to be used is in the range of 0.02 to 2 parts by weight, preferably 0.05 to 1 part by weight, based on 100 parts by weight of the resin solids in the coating material. is there. If the amount is less than 0.02 parts by weight, the storage stability is reduced. On the other hand, if it exceeds 2 parts by weight, water resistance and coating workability are undesirably reduced.

The aqueous coating composition of the present invention may further contain a pigment, a filler, an aggregate, a pigment dispersant, a wetting agent,
Additives for paints such as antifoaming agents, plasticizers, film-forming aids, organic solvents, preservatives, fungicides, pH adjusters, rust inhibitors, curing catalysts can be appropriately selected and combined and combined. .

The aqueous coating composition of the present invention is applied to a substrate surface by a conventionally known method, for example, a method such as roller coating, spray coating, or brush coating.

As the base material surface, concrete used for a part requiring waterproofness, such as a building roof or an outer wall surface, is used.
Mortar, slates, slates, nitrogen-based building materials, metals, plastics, and the like, and the surfaces of old paint films coated on them. An aqueous or solvent-type undercoat material can be applied to the substrate surface, and after applying the undercoat material, the above-mentioned aqueous coating composition can be applied. Examples of the undercoat material include an acrylic resin type, an acrylic rubber type, a chloride rubber type, a styrene-butadiene rubber type, an emulsion type sealer such as an epoxy type, a primer, and a base repair material containing cement, and in particular, Acrylic resin sealers and polymer cements are preferred.

[0066]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples. Note that “parts” and “%” indicate “parts by weight” and “% by weight”.

Production of Copolymer Aqueous Dispersion (A) Production Example 1 28.5 l of deionized water was placed in a two-liter four-necked flask.
And 0.1 part of Newcol 707SF (manufactured by Nippon Emulsifier Co., Ltd., anionic surfactant having a polyoxyethylene chain, non-volatile content: 30%). To this, 3% of the pre-emulsion obtained by emulsifying the following composition and 25% of 10.5 parts of a solution in which 0.5 parts of ammonium persulfate was dissolved in 10 parts of deionized water were added, and added. After minutes, the remaining pre-emulsion and the remaining aqueous solution of ammonium persulfate were added dropwise over 4 hours.

Deionized water 55.8 parts n-butyl methacrylate 94.3 parts diacetone acrylamide 3 parts hydroxyethyl acrylate 2.5 parts acrylic acid 0.2 parts Newcol 707SF 6.6 parts Dropping is completed. After that, it was kept at 85 ° C. for another 2 hours,
The temperature was lowered to 40-60 ° C. Then, pH 8 with ammonia water
To 9 and a 50% solids aqueous dispersion of copolymer (A-
1) was obtained.

Production Examples 2 to 7 Copolymer aqueous dispersions (A-2) to (A-7) were prepared in the same manner as in Production Example 1 except that the monomers in the pre-emulsion to be dropped had the compositions shown in Table 1. ) Got.

(Note 1) "Silaprene FM-071"
1 ": methacrylate having a polymethylsiloxane group, manufactured by Chisso, molecular weight 1,000

[0071]

[Table 1]

Production Example 8 Production of Aqueous Copolymer Dispersion (B) 79 parts by weight of isopropyl alcohol were charged into a flask, and the temperature was raised while stirring to the reflux temperature (about 84 ° C.). Then, while maintaining the temperature at the reflux temperature, the following monomer mixture was added dropwise for 4 hours.

Styrene 10 parts n-butyl methacrylate 58 parts Acrylic acid 7 parts KBM-502 (Note 2) 15 parts Sylaprene FM-0711 (Note 1) 10 parts Azobisisobutyronitrile 1 part Then reflux temperature After aging for 2 hours while maintaining the temperature, the mixture was cooled to room temperature to obtain a nearly colorless and transparent viscous copolymer solution having a nonvolatile content of 56%. Subsequently, the obtained copolymer solution was transferred to a diluting tank, 820 parts of deionized water and 9.8 parts of triethylamine were added, and the temperature was raised to 50 ° C.
After stirring for 2 hours while maintaining the temperature, the mixture was cooled to obtain an almost colorless translucent aqueous dispersion (B-1) having a nonvolatile content of 10%.

(Note 2) KBM-502: an alkoxysilyl group-containing monomer manufactured by Shin-Etsu Chemical Co., Ltd. Production Examples 9 to 12 In Production Example 8, the monomer mixture to be dropped is shown in Table 2.
The same procedure as in Production Example 8 was carried out except that the monomer mixture shown in (1) was used, to obtain light milky-white aqueous dispersions (B-2) to (B-4) and (B-6) having a nonvolatile content of 10%. Was.

(* 3) KBM-503: an alkoxysilyl group-containing monomer manufactured by Shin-Etsu Chemical Co., Ltd. (* 4) FAMAC: Nippon Mektron, perfluoroalkyl methacrylate, fluorine concentration: 60.7 wt. % Production Example 13 A flask was charged with 0.15 part of ammonium dodecylbenzenesulfonate and 145 parts of deionized water, and heated to 85 ° C. Subsequently, the following monomer mixture was dispersed in 80 parts of water using a homomixer.
0 parts were added. The aqueous dispersion was dropped into the flask over 5 hours and aged for 2 hours to obtain a milky-white aqueous dispersion (B-5) having a nonvolatile content of 30%. The obtained aqueous dispersion was diluted with deionized water to a nonvolatile content of 10% and used.

Styrene 10 parts n-Butyl methacrylate 64 parts Hydroxyethyl acrylate 3 parts Acrylic acid 3 parts KBM-503 (Note 3) 10 parts Thylaplane FM-0711 (Note 1) 10 parts Dodecylbenzene sulfone 8.7 parts of ammonium acid

[0077]

[Table 2]

Preparation of Water-Based Coating Examples and Comparative Examples The following composition was added to a 4-liter stainless steel container, and the mixture was stirred with a disper for 30 minutes to obtain a pigment-dispersed paste.

960 parts of tap water Ethylene glycol 288 parts “Nopco Santo K” (manufactured by San Nopco, pigment dispersant) 48 parts “Adecanol UH-420” (manufactured by Asahi Denka Co., Ltd., thickener) 16 parts “SN” Deformer A63 "(manufactured by San Nopco, defoamer) 32 parts Titanium white 3520 parts Total 4864 parts Next, the copolymer aqueous dispersions (A) and (B) obtained above were placed in a 2-liter stainless steel container. ), Pigment paste and the like were mixed as shown in Table 3, and mixed and stirred to obtain each water-based paint. Each of the obtained water-based paints was subjected to the following performance tests. Table 3 shows the results.

(Note 5) "TSF484": Toshiba Silicon Corporation
Dimethylpolysiloxysan (Note 6) "Primal TT-935": Roam and Haas Co., Ltd., thickener (Note 7) "Slaof S": Takeda Pharmaceutical Co., Ltd., preservative performance test ( 1) Appearance of coating film: Each water-based coating was applied to a glass plate using a film applicator having a gap of 150 μm, dried at 20 ° C. for 2 hours, and the appearance of the coating film was visually evaluated.

：: no repelling, good gloss ×: glossy, repelling, and coating film not formed uniformly (2) Water permeability: thickness 6 specified in JIS A-5430
mm on a flexible board (slate)
White ”(Kansai Paint Co., Ltd., acrylic emulsion series)
Was diluted with water to 50%, and the coating amount was reduced to 50% with a roller.
g / m ^2, and after standing for 2 hours, each of the aqueous paints obtained above was adjusted to 70 KU with a stirrer viscometer and applied by air spray. This was left at 20 ° C. for 2 weeks to obtain each coated plate.

According to the water permeability test B method of JIS A-6909 (1995), a wax pipe having a diameter of 75 mm was fixed to each coated plate with a two-part epoxy adhesive. On the next day, pour water into this so that the height is 250 mm.
The amount of reduced water was read from the difference from the height of the water head after 4 hours, and the reduced amount per 1 m ² was determined as the permeation amount of the coating film [ml / (m ²
Day)].

Water permeability = Amount of water reduced (ml / day) /
Water contact area (m ² ) (3) Water repellency: A water droplet of 0.03 cc of deionized water is formed on each coated plate prepared in the same manner as in (2) above, and the contact angle of the water droplet is measured by Kyowa Chemical. Contacta Gourmet Tartar D
It was measured by CCA type. The larger the contact angle, the better the water repellency.

(4) Persistence of water repellency: Each coated plate used in the above (3) was installed in Hiratsuka City, Kanagawa Prefecture at an inclination of 30 ° to the south, and was exposed outdoors for one month. The contact angle of the coating film after the exposure was measured.

(5) Accelerated weather resistance: For each coated plate prepared in the same manner as in the above (2), using a sunshine weatherometer, a gloss retention of 60 ° gloss of the coating film after a 1000-hour test ( %).

[0086]

According to the method of the present invention, a coating film having excellent water repellency and waterproofness can be formed without deteriorating weather resistance, stain resistance and initial drying property.

[0087]

[Table 3]

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁶ Identification code FI C09D 155/00 C09D 155/00 (72) Inventor Naoki Miyata 4-171-1, Higashi-Yawata, Hiratsuka-shi, Kanagawa Kansai Paint Co., Ltd. (72) Inventor Nobuto Hirata 4-17-1, Higashi-Hachiman, Hiratsuka-shi, Kanagawa Prefecture Kansai Paint Co., Ltd.

Claims (4)

[Claims] (A) (A) 50 to 98% by weight of a (meth) acrylate having an alkyl group having 4 or more carbon atoms, (b) 2 to 10% by weight of a carbonyl group-containing monomer, and (A) c) from 0 to 4 other polymerizable unsaturated monomers
(B) (d) an aqueous dispersion of a copolymer obtained by emulsion polymerization of a monomer mixture containing 8% by weight of the following structural formulas (I) and (I):
3 to 70% by weight of at least one monomer selected from the monomers represented by I), (Wherein, R ¹ is a hydrogen atom or a methyl group, R ² is the same or different and is a phenyl group or an alkyl group having 1 to 6 carbon atoms, n ¹ is an integer of ¹ to 10, and n ² is 5 to ²⁰⁰ Are shown as integers.) (Wherein, R ³ is a hydrogen atom or a methyl group, X is a hydrogen atom or a fluorine atom, n ³ is an integer of 1 to 8, n ⁴ is 1 to
An integer of 30 is shown. (E) 1 to 40% by weight of an alkoxysilyl group-containing monomer, (f) a carboxyl group,
It contains 1 to 25% by weight of a polymerizable unsaturated monomer having one kind of functional group selected from the group consisting of a sulfonic acid group and an amino group, and 0 to 95% by weight of (g) another polymerizable unsaturated monomer. monomer - mixture obtained by copolymerizing a copolymer solution or aqueous dispersion, and (C) water-based paint which comprises a hydrazine derivative having at least two -NH-NH ₂ containing groups per molecule Composition. 2. Copolymer aqueous solution or aqueous dispersion (B)
The aqueous coating composition according to claim 1, wherein the monomer mixture for the production of (i) contains 1 to 10% by weight of (h) a carbonyl group-containing monomer. 3. An aqueous solution or aqueous dispersion of a copolymer (B).
Is produced by adding water and a neutralizing agent to a copolymer solution obtained by subjecting a monomer mixture to radical polymerization in an organic solvent to make the mixture water-soluble or water-dispersed. An aqueous coating composition as described in the above. 4. The aqueous coating composition according to claim 1, wherein the weight ratio of the solid content of the copolymer aqueous dispersion (A) and (B) is 70/30 to 99/1. .