JP2022132170A - Aqueous coating material - Google Patents

Abstract

To provide an aqueous coating material which suppresses deterioration in adhesion, whitening of a coating film, and the like due to coating conditions and exhibits excellent adhesion to various substrates and coating films.SOLUTION: The aqueous coating material is obtained by mixing a main agent containing an epoxy resin emulsion (A) and a curing agent containing an amino group-containing resin (B). The aqueous coating material contains an acrylic resin emulsion (C). The mixing weight ratio (solid content) of the epoxy resin emulsion (A) to the acrylic resin emulsion (C) is (A)/(C)<1.SELECTED DRAWING: None

Description

The present invention relates to novel aqueous coatings.

BACKGROUND ART In coating interior and exterior wall surfaces, floor surfaces, etc. of buildings, various undercoating materials are selected and used in consideration of adhesion to substrates. Conventionally, solvent-based undercoat materials have mainly been used, but recently, water-based undercoat materials have been adopted in consideration of the environment, safety, and the like. For example, Patent Literature 1 describes a two-part reaction-curable water-based coating composition for undercoating, which comprises a main agent containing an epoxy resin emulsion and a curing agent containing an amine resin.

However, water-based undercoat materials may be inferior in adhesion to solvent-based undercoat materials. In recent years, in particular, exterior building materials used for exterior wall surfaces have been provided with various coating films having functionality such as high weather resistance and stain resistance. In repairing such a coating film, it may be difficult to obtain sufficient adhesion with a water-based undercoat material. Furthermore, with epoxy resin-based primers, problems such as reduced adhesion and whitening of the coating film may occur due to amine brushing, etc., depending on the coating conditions such as low temperature or high humidity. It tends to be more pronounced in water systems compared to

JP-A-2018-53028

The present invention has been made in view of such problems, and provides a water-based coating material that can ensure sufficient adhesion to various substrates and coating films under various coating conditions. with the aim of obtaining

As a result of intensive studies on such problems, the present inventors have found an aqueous solution obtained by mixing an acrylic resin emulsion in a specific weight ratio with an aqueous coating material having a main agent containing an epoxy resin emulsion and a curing agent containing an amino group-containing resin. A coating material was discovered, and the present invention was completed.

That is, the present invention has the following features.
1. An aqueous coating material having a main agent containing an epoxy resin emulsion (A) and a curing agent containing an amino group-containing resin (B), wherein the aqueous coating material contains an acrylic resin emulsion (C), and the epoxy resin emulsion (A ) and the acrylic resin emulsion (C) in a mixing weight ratio (solid content) of (A)/(C)<1.
2. 1. The acrylic resin emulsion (C) is a polymer of a monomer group containing an epoxy group-containing monomer. Aqueous coating material according to.
3. 1. Further, it contains an organic solvent (D) having a boiling point of 200° C. or higher and a solubility in water at 20° C. of 10 g/100 g H ₂ O or lower. or 2. Aqueous coating material according to any one of.

The water-based coating material of the present invention suppresses deterioration of adhesion and whitening of the coating film due to coating conditions, and exhibits excellent adhesion to various substrates and coating films.

The present invention relates to an aqueous coating material (hereinafter also simply referred to as "aqueous coating material") having a main agent containing an epoxy resin emulsion (A) and a curing agent containing an amino group-containing resin (B).

The epoxy resin emulsion (A) of the present invention (hereinafter also simply referred to as "component (A)") is obtained by dispersing and emulsifying an epoxy resin in an aqueous medium. When the epoxy resin is dispersed in the aqueous medium, an emulsifier or the like may be used as necessary. Incidentally, the aqueous medium is a medium that mainly contains water, and if necessary, for example, even if a water-soluble solvent such as a lower alcohol, a polyhydric alcohol, an ether compound, an ester compound, an alkylene oxide-containing compound is mixed. good.

The epoxy resin of component (A) may be any one that can be dispersed in an aqueous medium, and may be either a solid epoxy resin and/or a liquid epoxy resin. As such epoxy resins, for example, resins containing one or more, preferably two or more epoxy groups in the molecule can be used. Examples include aromatic epoxy resins, aliphatic epoxy resins, alicyclic epoxy resins, A polybutadiene resin having an epoxy group, a polyurethane resin having an epoxy group, and the like are included. In the present invention, aromatic epoxy resins are preferred, and examples thereof include bisphenol A type epoxy resins, bisphenol AD type epoxy resins, bisphenol F type epoxy resins, novolac type epoxy resins, etc. Among these, bisphenol A type epoxy resins are particularly preferred. , bisphenol AD type epoxy resin, and bisphenol F type epoxy resin. Furthermore, the above epoxy resins may be those with increased molecular weights as necessary, fatty acid-modified epoxy resins obtained by reacting fatty acids, or amine-added epoxy resins obtained by addition reaction of amino group-containing compounds (amine It may also be obtained by making a modified epoxy resin) water-based. These can be used singly or in combination of two or more. In addition, the solid type epoxy resin is solid at room temperature (23° C.), and the liquid type epoxy resin is liquid at room temperature (23° C.).

In the present invention, it is preferable that the component (A) contains a solid epoxy resin (a1) as an essential component. Examples of such an embodiment include an embodiment containing only the solid epoxy resin (a1) and an embodiment containing the solid epoxy resin (a1) and the liquid epoxy resin (a2). Thereby, the effects of the present invention can be sufficiently obtained. When the solid epoxy resin (a1) and the liquid epoxy resin (a2) are mixed, the mixing ratio (solid content weight ratio) is preferably 100:0 to 5: although it depends on the epoxy equivalent of each epoxy resin. 95 (more preferably 100:0 to 10:90). In the present invention, "α to β" has the same meaning as "more than or equal to α and less than or equal to β".

The method for preparing component (A) is not particularly limited. Examples include a method of emulsifying by mixing with a medium (including an emulsifier as necessary). In addition, at the time of said preparation, it can also heat as needed. In the present invention, when a solid epoxy resin and a liquid epoxy resin are used in combination, it is preferable to prepare respective aqueous dispersions of the solid epoxy resin and the liquid epoxy resin, and then mix them before use. The resin solid content of the epoxy resin aqueous dispersion is not particularly limited, but is preferably 10 to 80% by weight (more preferably 20 to 70% by weight).

As the emulsifier, for example, anionic surfactants and nonionic surfactants can be used alone or in combination.
Examples of anionic surfactants include alkali metal sulfonates such as sodium dodecylbenzenesulfonate, sodium laurylnaphthalenesulfonate, sodium stearyldiphenylether disulfonate; sodium lauryl sulfate, sodium polyoxyethylene lauryl ether sulfate, polyoxyethylene Sulfate ester alkali metal salts such as octylphenyl ether sodium sulfate and the like are included.
Examples of nonionic surfactants include polyoxyethylene lauryl ether, polyoxyethylene oleyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene nonylphenyl ether, and oxyethylene/oxypropylene block copolymers.
The amount of the emulsifier is preferably in the range of 0.1 to 15% by weight (more preferably 0.1 to 10% by weight, still more preferably 0.5 to 5% by weight) relative to the resin solid content. .

The average particle size of component (A) of the present invention is not particularly limited, but is preferably 100 to 1000 nm (more preferably 150 to 900 nm, still more preferably 200 to 800 nm, particularly preferably 300 to 600 nm). If the average particle size is within such a range, advantageous effects can be obtained in sealability, resistance to efflorescence, resistance to whitening, and the like. The average particle size referred to here is a value measured by a dynamic light scattering method.

The component (A) of the present invention preferably has an epoxy equivalent x _a of 100 to 3000 (more preferably 110 to 2000, still more preferably 120 to 1500). Here, the “epoxy equivalent x _a ” is the number of grams [g/eq] of the resin solid content containing one gram equivalent of epoxy groups, and the weight average molecular weight of the epoxy resin is the number of epoxy groups per molecule. is a value divided by

As the above component ( _A ), those having different epoxy equivalents xa, average particle diameters, etc. can be mixed and used.

The amino group-containing resin (B) of the present invention (hereinafter also simply referred to as "(B) component") reacts with the epoxy resin emulsion (A) to form a coating film. As such component (B), for example, polyamine resins containing two or more amino groups in one molecule can be used. Examples include aliphatic polyamines, alicyclic polyamines, aromatic polyamines, heterocyclic amines and A modified polyamine resin obtained by modifying the amino group of a polyamine resin, and the like are included. For modification of the polyamine resin, known methods can be used, such as amidation of amino groups, Mannich reaction between amino groups and carbonyl compounds, addition reaction between amino groups and epoxy groups, addition of amino groups and styrene. reactions and the like. As the component (B), aliphatic polyamides, alicyclic polyamides, aromatic polyamides, aliphatic polyamidoamines, alicyclic polyamidoamines, aromatic polyamidoamines and the like can also be used. These can be used singly or in combination of two or more.

In the present invention, the component (B) preferably contains, for example, one or more selected from aliphatic polyamines and modified aliphatic polyamines. As a result, when mixed with a main agent containing an epoxy resin emulsion, the property of adhesion to the base material and the coating film and the adhesion are improved. Examples of aliphatic polyamines include linear aliphatic polyamines such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine, dipropylenediamine, diethylaminopropylamine, hexamethylenediamine; N-aminoethylpiperazine, bis(4-amino -3-methylcyclohexyl)methane, mensenediamine, isophoronediamine, 4,4'-diaminodicyclohexylmethane, 3,9-bis(3-aminopropyl)-2,4,8,10-tetraoxaspiro [5. 5] Cycloaliphatic polyamines such as undecane (spiroacetaldiamine), norbornanediamine, tricyclodecanediamine, 1,3-bisaminomethylcyclohexane; and aliphatic aromatic amines such as meta-xylenediamine. In the present invention, it is particularly preferred to contain one or more selected from meta-xylenediamine and styrene addition reaction products of meta-xylenediamine.

The mode of the component (B) is not particularly limited, but a water-soluble resin that can be dissolved in an aqueous medium, a water-dispersible resin that can be dispersed in an aqueous medium, or the like can be used. In the present invention, it is preferable that the component (B) contains a water-soluble resin. In this case, the storage stability is excellent, and when mixed with the main agent, the compatibility and reactivity with the epoxy resin emulsion (A) are enhanced, and the adhesion to the substrate and coating film, and the adhesion are further improved. It is possible to form a coating film with improved water resistance and excellent coating film appearance. The component (B) may be a solvent-free type (solid content: 100% by weight) or may be prepared by dissolving or dispersing the component (B) in an aqueous medium in advance. The solid content of component (B) is preferably 50% by weight or more (more preferably 55% by weight or more, still more preferably 60% by weight or more). The upper limit of the solid content of component (B) is 100% by weight or less. When this range is satisfied, the effects of the present invention can be sufficiently exhibited. Incidentally, the aqueous medium is a medium that mainly contains water, and if necessary, for example, even if a water-soluble solvent such as a lower alcohol, a polyhydric alcohol, an ether compound, an ester compound, an alkylene oxide-containing compound is mixed. good.

The active hydrogen equivalent yb of component ( _B ) is preferably 10 to 1000 (more preferably 50 to 800, still more preferably 80 to 600). Here, the "active hydrogen equivalent y _b " is the number of grams [g/eq] of the resin solid content containing 1 gram equivalent of active hydrogen groups, and the weight average molecular weight of the amino group-containing resin per molecule. It is a value divided by the number of hydrogen atoms in the amino group.

The water-based coating material of the present invention comprises the main agent and the curing agent, the epoxy equivalent ([X _A ]: solid content conversion value) of the component (A) in the main agent, and the active hydrogen of the component (B) in the curing agent. The ratio [X _A /(Y _B )] of the equivalent ([Y _B ]; solid content conversion value) is preferably 0.1 to 3 (more preferably 0.5 to 2, further preferably 0.7 to 1 .5) is preferably mixed. In such a case, the adhesion of the water-based coating material to the base material and the coating film is improved. Furthermore, the stability and pot life of the aqueous coating material can be increased.

The above X _A and the above Y _B are obtained from the number of blended parts at the time of mixing, and specifically, the above [X _A ] is the blended amount of component (A) contained in the main agent (parts by weight of solid content). is divided by the epoxy equivalent x _a of component (A). The above [Y _B ] is a value obtained by dividing the compounding amount (parts by weight of solid content) of the component (B) contained in the curing agent by the active hydrogen equivalent y _b of the component (B).

The curing agent of the present invention contains the above component (B) and preferably has a solid content of 10% by weight or more (more preferably 15% by weight, still more preferably 20% by weight). The upper limit of the solid content is 100% by weight or less. When this range is satisfied, the effects of the present invention can be sufficiently exhibited. The solid content can be adjusted by mixing the aqueous medium. Specifically, the aqueous medium in the curing agent may be one mixed at the time of production of the curing agent, or may be included as a medium such as component (B) above. When water is contained as the aqueous medium, the water content in the curing agent is preferably 30% by weight or less (more preferably 20% by weight or less, still more preferably 10% by weight or less), and substantially contains water. It is also preferable to have no mode. When this range is satisfied, the storage stability of the curing agent can be sufficiently exhibited, and the activity of the above component (S3) is enhanced, and when mixed with the main agent, the substrate, the adhesion to the coating film, and the adhesion can be further enhanced.

The water-based coating material of the present invention contains an acrylic resin emulsion (C) (hereinafter also simply referred to as "(C) component") in addition to the above component (A) and the above component (B). The mixing weight ratio (solid content) of component and component (C) is (A)/(C)<1 (preferably <0.9, more preferably <0.8). The lower limit is not particularly limited as long as component (A) is included, but is preferably 0.1<(A)/(C) (more preferably 0.2<). By including the component (C) in such a mixing ratio, the concentration of the component (C) tends to increase near the surface of the formed coating film. and excellent adhesion to the coating film, and in particular, the adhesion to the existing coating film and the top coating film can also be enhanced. Furthermore, a coating film having excellent water resistance and coating film appearance can be formed.

The component (C) can be mixed with either or both of the main agent and the curing agent, but is preferably mixed with the main agent in the present invention. As a result, the above-mentioned effects are further enhanced, and a coating film excellent in aesthetics in which amine brushing or the like is suppressed can be formed.

The component (C) has a (meth)acrylic acid alkyl ester as a main component of the resin skeleton, and is obtained by copolymerizing other monomers and other polymerizable monomers as necessary. In the present invention, alkyl acrylate and alkyl methacrylate are collectively referred to as alkyl (meth)acrylate. Moreover, a monomer is a general term for compounds having a polymerizable unsaturated double bond.

In the present invention, it is preferable that a hydrophobic monomer is included in the monomer group constituting component (C). Hydrophobic monomers include, for example, long-chain alkyl (meth)acrylates, aromatic group-containing monomers, and the like.

As the long-chain alkyl (meth)acrylate, an alkyl (meth)acrylate having an alkyl group having 4 or more carbon atoms can be used, such as n-butyl (meth)acrylate, t-butyl (meth)acrylate, isobutyl (meth)acrylate. Acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, octadecyl (meth)acrylate, cyclohexyl (meth)acrylate and the like. be done. These can be used alone or in combination of two or more.

Examples of aromatic group-containing monomers include styrene-based monomers such as styrene, 2-methylstyrene, vinyltoluene, ethylvinylbenzene, vinylnaphthalene, chlorostyrene, phenyl (meth)acrylate, benzyl (meth)acrylate, phenoxyethyl Aromatic group-containing (meth)acrylates such as (meth)acrylates, and the like are included. These can be used singly or in combination of two or more.

In the present invention, it is particularly preferable that the hydrophobic monomer includes an alkyl (meth)acrylate having an alkyl group with 6 or more (preferably 8 or more) carbon atoms.

The weight ratio of the hydrophobic monomer in the monomer group is preferably 10% by weight or more, more preferably 30% by weight or more, and still more preferably 40% by weight or more. Although the upper limit is not particularly limited, it is preferably 99.5% by weight or less. In such a case, the compatibility with the organic solvent (D), which will be described later, is enhanced, and the effects of the present invention can be enhanced.

Specific examples of other monomers include amide group-containing monomers, carbonyl group-containing monomers, carboxyl group-containing monomers, amino group-containing monomers, epoxy group-containing monomers, hydroxyl group-containing monomers, vinylidene halide monomers, and alkoxysilyl group-containing monomers. Monomers, ethylene, propylene, isoprene, butadiene, vinyl ether, vinyl ketone and the like. These can be used singly or in combination of two or more.

In the present invention, it is preferred that an epoxy group-containing monomer is included. Examples of epoxy group-containing monomers include glycidyl (meth)acrylate, diglycidyl fumarate, 3,4-epoxycyclohexyl (meth)acrylate, 3,4-epoxyvinylcyclohexane, allyl glycidyl ether, and ε-caprolactone-modified glycidyl (meth)acrylate. acrylate, β-methylglycidyl (meth)acrylate and the like. These can be used alone or in combination of two or more.

In the present invention, the epoxy group-containing monomer is preferably 0.5 to 50% by weight (more preferably 1 to 30% by weight) in the monomers constituting component (C). As a result, deterioration of adhesion and whitening of the coating film due to amine brushing can be suppressed, and sufficient physical properties of the coating film can be exhibited.

Specific examples of other monomers include
Examples of nitrile group-containing monomers include (meth)acrylonitrile, vinylidene cyanide, α-cyanoethyl (meth)acrylate, etc.
Examples of amide group-containing monomers include maleic acid amide, (meth)acrylamide, N-monoalkyl(meth)acrylamide, N,N-dialkyl(meth)acrylamide, 2-(dimethylamino)ethyl (methacrylate), N-[ 3-(dimethylamino)propyl](meth)acrylamide, vinylamide, etc.
Examples of carbonyl group-containing monomers include acrolein, diacetone (meth)acrylamide, vinyl methyl ketone, vinyl ethyl ketone, vinyl butyl ketone, etc.
Examples of carboxyl group-containing monomers include (meth)acrylic acid, crotonic acid, maleic acid, itaconic acid, fumaric acid, isocrotonic acid, salicylic acid, etc.
Examples of amino group-containing monomers include aminomethyl acrylate, aminoethyl acrylate, aminopropyl (meth)acrylate, amino-n-butyl (meth)acrylate, butylvinylbenzylamine, vinylphenylamine, p-aminostyrene, N-methyl aminoethyl (meth)acrylate, Nt-butylaminoethyl (meth)acrylate, etc.
Examples of hydroxyl group-containing monomers include hydroxypropyl (meth)acrylate, ethylene glycol mono(meth)acrylate, glycerol mono(meth)acrylate, etc.
Examples of vinylidene halide-based monomers include, for example, vinylidene fluoride,
Examples of alkoxysilyl group-containing monomers include vinyltrimethoxysilane, vinyltriethoxysilane, γ-(meth)acryloyloxypropyltrimethoxysilane, γ-(meth)acryloyloxypropyltriethoxysilane, γ-(meth)acryloyloxy propylmethyldimethoxysilane and the like. These can be used singly or in combination of two or more.

The above component (C) can be produced by emulsion polymerization of a group of monomers in which the above monomers are appropriately mixed. As the polymerization method, a known method may be adopted, and in addition to ordinary emulsion polymerization, soap-free emulsion polymerization, feed emulsion polymerization, seed emulsion polymerization, multistage emulsion polymerization, and the like can also be adopted. At the time of polymerization, for example, emulsifiers, initiators, dispersants, polymerization inhibitors, polymerization inhibitors, buffers, chain transfer agents, pH adjusters and the like can be used.

As the emulsifier, various surfactants that can be used for emulsion polymerization can be used, and these may be reactive type having a polymerizable unsaturated double bond (reactive surfactant). As emulsifiers, for example, anionic surfactants and nonionic surfactants can be used alone or in combination. Specifically, for example, it can be appropriately selected from those described for the component (A) above.

The glass transition temperature (hereinafter simply referred to as "Tg") of the component (C) can be adjusted by selecting the types of the monomers, the mixing ratio, and the like. This Tg may be appropriately set in consideration of the final required performance and the like, but it is preferable to have a Tg of more than -8°C and 80°C or less (more preferably -7°C or more and 60°C or less). Two or more different Tg's can also be used as the component (C). In this case, the total Tg preferably satisfies the above range. The glass transition temperature can be obtained by the Fox calculation formula.

The average particle size of component (C) is not particularly limited, but is preferably 300 nm or less (more preferably 20 to 250 nm, still more preferably 30 to 200 nm). If the average particle size is within such a range, advantageous effects can be obtained in impregnation reinforcing properties, sealing properties, resistance to efflorescence, resistance to whitening, and the like. Two or more kinds of component (C) having different average particle sizes can also be used. The average particle size referred to here is a value measured by a dynamic light scattering method.

In the present invention, the ratio of the average particle sizes of the component (A) and the component (C) is preferably (A)/(C)>1 (more preferably >1.2). As a result, the concentration of the component (C) tends to increase in the vicinity of the surface of the formed coating film, and as a result, the influence of the coating conditions can be suppressed, and even better physical properties of the coating film can be exhibited. In addition, when the above component (A) and the above component (C) contain two or more types with different average particle sizes, the average particle size of the component (A) and the average particle size of the component (C) It is preferred that the values satisfy the above conditions.

Furthermore, it is preferable that the gel fraction of the film formed by the component (C) is 10% or more (preferably 20% or more, more preferably 30% or more). Although the upper limit is not particularly limited, it is practically preferably 95% or less (more preferably 90% or less). When the film formed from the component (C) satisfies such a range, the above effects are enhanced and sufficient adhesion can be ensured.

In the present invention, the gel fraction is obtained by coating the component (C) on a polyester film to a coating thickness of 0.5 mm and drying at 50° C. for 3 days to form a coating. After using a test piece and immersing it in acetone for 24 hours, it is calculated by the following formula.
Gel fraction (%) = (coat weight after immersion/coat weight before immersion) x 100

The method for adjusting the gel fraction is not particularly limited. , a method of copolymerizing a monomer having a functional group such as a carboxyl group, a hydroxyl group, an epoxy group, an amide group, a carbonyl group, an acetoacetyl group, etc., and a method of copolymerizing the functional group during and / or after the polymerization. Examples include a method of adding a cross-linking agent capable of reacting with the group.

In the present invention, water-soluble resins and/or resin emulsions other than the above components (A) and (C) can be mixed as long as the effects of the present invention are not impaired. Examples of resin types include acrylic resins (excluding component (C) above), urethane resins, silicon resins, fluororesins, vinyl acetate resins, polyester resins, alkyd resins, vinyl chloride resins, etc., or combinations thereof. and the like.

Further, the water-based coating material of the present invention is an organic solvent (D) (hereinafter simply referred to as "(D) component") having a boiling point of 200° C. or higher and a solubility in water of 10 g/100 g H ₂ O or less at 20° C. ) is preferably included. In addition to the above component (C), by further containing the component (D) in combination, the compatibility and reactivity of the above component (A), the above component (B) and the above component (C) are enhanced, and excellent film formability can be obtained. As a result, a dense coating film can be formed, the influence of coating conditions can be efficiently suppressed, and amine brushing and the like are more difficult to occur.

The above component (D) can be mixed with either or both of the main agent and the curing agent. In the present invention, the component (D) is preferably mixed with the main agent. As a result, the above-mentioned effects are further enhanced, and a coating film excellent in aesthetics in which amine brushing or the like is sufficiently suppressed can be formed.

Component (D) is not particularly limited as long as it is an organic solvent having a boiling point of 200° C. or higher and a solubility in water of 10 g/100 g/100 g H ₂ O or lower at 20° C. Examples include ethylene glycol monohexyl ether. , ethylene glycol dibutyl ether, ethylene glycol ether compounds such as ethylene glycol phenyl ether; diethylene glycol ether compounds such as diethylene glycol monohexyl ether, diethylene glycol monobutyl ether acetate, diethylene glycol dibutyl ether; propylene glycol phenyl ether, dipropylene glycol-n-butyl ether, di Propylene glycol ether compounds such as propylene glycol-tert-butyl ether, dipropylene glycol-n-propyl ether, tripropylene glycol-n-butyl ether; 2-ethyl-1,3-hexanediol, 2,2,4-trimethyl-1 ,3-pentanediol monoisobutyrate, 2,2,4-trimethyl-1,3-pentanediol diisobutyrate, benzyl alcohol and the like. These can be used singly or in combination of two or more. Component (D) has a boiling point of 200° C. or higher, and its upper limit is preferably 350° C. or lower (more preferably 300° C. or lower). Further, the solubility of component (D) in water at 20°C is 10 g/100 g H ₂ O or less, preferably 8 g/100 g H ₂ O or less, and the lower limit thereof is preferably 0 g/100 g H ₂ O or more (more preferably is 0.01 g/100 g H ₂ O or more, more preferably 0.05 g/100 g H ₂ O or more, and particularly preferably 0.1 g/100 g H ₂ O or more).

In the present invention, it is particularly selected from propylene glycol ether compounds such as propylene glycol phenyl ether, dipropylene glycol-n-butyl ether, dipropylene glycol-tert-butyl ether, dipropylene glycol-n-propyl ether, and tripropylene glycol-n-butyl ether. It is preferable to include at least one kind of

The amount of component (D) mixed is preferably 1 to 80 parts by weight (more preferably 2 to 60 parts by weight) per 100 parts by weight of component (A) (solid content). In the case of such a range, the above effects can be sufficiently exhibited.

Furthermore, the aqueous coating material of the present invention can contain a silane compound (S). Examples of the silane compound (S) include a glycidyl group-containing silane compound (S1), an alkoxysilane compound (S2), an amino group-containing silane compound (S3), and the like. These can be used singly or in combination of two or more.

Examples of the glycidyl group-containing silane compound (S1) (hereinafter also simply referred to as "(S1) component") include a compound having a glycidyl group (epoxy group) and an alkoxysilyl group, or a compound having a glycidyl group and a cyclic siloxane. Available. These can be used singly or in combination of two or more.

Examples of compounds having a glycidyl group (epoxy group) and an alkoxysilyl group include glycidyl group-containing silane coupling agents and hydrolyzed oligomers thereof.

Specifically, glycidyl group-containing silane coupling agents include, for example, glycidoxymethyltrimethoxysilane, glycidoxymethyltriethoxysilane, β-glycidoxyethyltrimethoxysilane, β-glycidoxyethyltriethoxy Silane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyldimethyl Methoxysilane, γ-glycidoxypropyl(ethyl)dimethoxysilane, β-3,4-epoxycyclohexylethyltrimethoxysilane, β-3,4-epoxycyclohexylethyltriethoxysilane, 8-glycidoxyoctyltrimethoxysilane , 8-glycidoxyoctylmethyldimethoxysilane, 8-glycidoxyoctylmethyldiethoxysilane, etc., preferably those having an epoxy equivalent _xn1 of 10 to 1000 (more preferably 50 to 500). mentioned. The term "epoxy equivalent x _n1 " as used herein is the number of grams [g/eq] of the silane compound containing one gram equivalent of epoxy group, and the weight average molecular weight of the glycidyl group-containing silane compound is defined as the epoxy group per molecule. is a value divided by the number of

The hydrolyzed oligomer of the glycidyl group-containing silane coupling agent has an alkoxysilyl group and a glycidyl group, preferably has an alkoxy group content of 10 to 80 wt% (more preferably 20 to 75 wt%), an epoxy equivalent of x Examples include those in which _n1 is 200 to 950 (more preferably 300 to 900). As such (N1) component, those having two or more kinds of alkoxysilyl groups, or those in which some or all of the alkoxysilyl groups are in the state of silanol groups can be used.

The compound having a glycidyl group and a cyclic siloxane is a silicone oligomer having only a glycidyl group as a reactive functional group, preferably having an epoxy equivalent x _n1 of 100 to 500 (more preferably 150 to 400). be done.

In particular, in the present invention, glycidyl group-containing silane coupling agents are suitable as the component (S1). Silane, β-glycidoxyethyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, β-3,4-epoxycyclohexylethyltrimethoxysilane, β-3,4 -preferably one or more selected from epoxycyclohexylethyltriethoxysilane, and one or more selected from β-3,4-epoxycyclohexylethyltrimethoxysilane and β-3,4-epoxycyclohexylethyltriethoxysilane; A more preferable aspect is to include. When these are used, the adhesion expression and adhesion to the base material and coating film are further improved. Furthermore, the stability and pot life of the aqueous coating material can be increased.

When the above component (S1) is included, it is preferably mixed with the main agent, and the mixing ratio is preferably 0.5 for the above component (S1) per 100 parts by weight of the above component (A) (solid content). ~50 parts by weight (more preferably 1 to 40 parts by weight). In such a case, the degree of adhesion to the substrate and the coating film is increased, and the adhesion is further improved. Furthermore, the stability and pot life of the aqueous coating material can be increased.

As the alkoxysilane compound (S2) (hereinafter also simply referred to as "(S2) component"), alkoxysilanes, hydrolytic condensates thereof, and the like can be used. These can be used singly or in combination of two or more. By using such a (S2) component, the adhesion to the substrate can be further enhanced.

Examples of such (S2) component include tetraethoxysilane, tetramethoxysilane, tetra-n-propoxysilane, tetraisopropoxysilane, tetraisobutoxysilane, tetrasec-butoxysilane, tetra-t-butoxysilane, tetraphenoxysilane, Tetrafunctional alkoxysilane compounds such as silane;

methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltributoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltripropoxysilane, ethyltributoxysilane, propyltrimethoxysilane, propyltriethoxysilane, Propyltripropoxysilane, Propyltributoxysilane, Butyltrimethoxysilane, Butyltriethoxysilane, Butyltripropoxysilane, Butyltributoxysilane, Hexyltrimethoxysilane, Hexyltriethoxysilane, Decyltrimethoxysilane, Trifluoropropyltrimethoxysilane Trifunctional alkylalkoxysilane compounds such as silane, phenyltrimethoxysilane, phenyltriethoxysilane, and phenyltributoxysilane;

Dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyldibutoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, diethyldibutoxysilane, diethyldipropoxysilane, dipropyldimethoxysilane, dipropyldiethoxysilane, dibutyldimethoxysilane, dibutyldi Bifunctional alkylalkoxysilane compounds such as ethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, diphenyldibutoxysilane, dimethoxymethylphenylsilane, methylphenyldiethoxysilane;
etc. These may be used alone or in combination of two or more.

In the present invention, the (S2) component preferably contains a trifunctional alkylalkoxysilane compound and/or a bifunctional alkylalkoxysilane compound. Furthermore, it is preferable to include one containing a phenyl group. Examples of such (S2) component include phenyltrimethoxysilane, dimethoxymethylphenylsilane, diphenyldimethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, phenyltributoxysilane, and diphenyldibutoxysilane. When these are used, the curability of the formed film is enhanced, and the adhesion and adhesion to the base material and the coating film are further improved. In particular, excellent effects can be exhibited in terms of improving adhesion and adhesion to substrates having an existing coating film.

When the above component (S2) is included, it can be mixed with either the main agent or the curing agent, or both. In the present invention, it is preferably mixed with the main agent. ) Component (S2) is preferably 0.5 to 30 parts by weight (more preferably 1 to 20 parts by weight) per 100 parts by weight of component (solid content). In such a case, the above effects can be fully exhibited.

As the amino group-containing silane compound (S3) (hereinafter also simply referred to as "(S3) component"), a compound having an amino group and an alkoxysilyl group, a compound having an amino group and a cyclic siloxane, or the like can be used. These can be used singly or in combination of two or more.

Examples of compounds having an amino group and an alkoxysilyl group include amino group-containing silane coupling agents, hydrolyzed oligomers thereof, and polymers having an alkoxysilyl group and an amino group. Specifically, as the amino group-containing silane coupling agent, for example,
γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyltriisopropoxysilane, γ-aminopropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane, N-β (aminoethyl)- γ-aminopropyltrimethoxysilane, N-β (aminoethyl)-γ-aminopropylmethyldimethoxysilane, N-β (aminoethyl)-γ-aminopropyltriethoxysilane, N-β (aminoethyl)-γ- aminopropylmethyldiethoxysilane, N-β (aminoethyl)-γ-aminopropyltriisopropoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-ureidopropyltrimethoxysilane, γ-anilinopropyltri Methoxysilane, γ-ureidopropyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, N-vinylbenzyl-γ-aminopropyltriethoxysilane, N-β (aminoethyl)-8-aminooctyltrimethoxysilane silane, γ-triethoxysilyl-N-(1,3-dimethyl-butylidene)-propylamine, and the like.

As the hydrolyzed oligomer of the amino group-containing silane coupling agent, one having an alkoxysilyl group and an amino group can be used.
As such a component (S3), those in which some or all of the alkoxysilyl groups are in the state of silanol groups can also be used.

In particular, in the present invention, amino group-containing silane coupling agents are suitable as the (S3) component. One or more selected from γ-aminopropylmethyldimethoxysilane and N-β(aminoethyl)-γ-aminopropylmethyldiethoxysilane are suitable. When these are used, the properties of adhesion to the base material and the coating film are improved.

The active hydrogen equivalent y _m of the component (S3) is preferably 10 to 500 (more preferably 20 to 400, and still more preferably 30 to 300). Here, the "active hydrogen equivalent y _m " is the number of grams [g/eq] of the amino group-containing silane compound containing 1 gram equivalent of active hydrogen groups, and the weight average molecular weight of the amino group-containing silane compound is 1. It is a value divided by the number of hydrogen atoms in the amino group per molecule.

When the above component (S3) is included, it is preferably mixed with the curing agent. parts by weight (more preferably 1 to 100 parts by weight). When such a range is satisfied, the storage stability is excellent, and when mixed with the main agent, it is possible to sufficiently exhibit the property of adhesion and adhesion to the substrate and coating film.

In the present invention, it is preferable to mix the catalyst (P) (hereinafter also simply referred to as "(P) component"). The component (P) promotes, for example, the reaction between the glycidyl group (epoxy group) and the amino group in the aqueous coating material, or the hydrolysis/condensation of the alkoxysilyl group. In particular, the adhesion to substrates having existing coating films can be further enhanced.

Examples of the component (P) include various aromatic carboxylic acids such as benzoic acid, salicylic acid, trihydroxybenzoic acid, phthalic acid, cinnamic acid, and benzenehexacarboxylic acid; trimethylamine, ethyldimethylamine, propyldimethylamine; , N′-dimethylpiperazine, pyridine, picoline, 1,8-diazabiscyclo(5,4,0)undecene-1 (DBU), benzyldimethylamine, 2-(dimethylaminomethyl)phenol (DMP-10), 2, Tertiary amines such as 4,6-tris(dimethylaminomethyl)phenol (DMP-30), hydroxylamines such as hydroxylamine and phenoxyamine, imidazole, 1-methylimidazole, 2-methylimidazole, 4(5) -Methylimidazole, 2-ethyl-4-methylimidazole, 2-ethylimidazole, imidazoles such as 2-phenylimidazole (B), and amines other than the above (S3); phenol novolak, o-cresol novolak , p-cresol novolak, t-butylphenol novolak, dicyclopentadiene cresol and other phenols, tin octylate, dibutyltin dilaurate, dibutyltin diacetate, organotitanate, sodium acetate and other organometallic compounds. These can be used singly or in combination of two or more. Among these, as the (P) component, in particular, organic tin compounds such as tin octylate, dibutyltin dilaurate, and dibutyltin diacetate; benzoic acid, salicylic acid, trihydroxybenzoic acid, phthalic acid, cinnamic acid, benzenehexa Various aromatic carboxylic acids such as carboxylic acid are preferably used.

The above component (P) can be mixed with the main agent and / or the curing agent, and the mixing amount is preferably 0 parts per 100 parts by weight of the above component (A) (solid content). 0.01 to 15 parts by weight (more preferably 0.02 to 10 parts by weight). Within such a range, the effects of the present invention can be enhanced.

In addition to the above components, the water-based coating material of the present invention may contain a coloring pigment, an extender pigment, an anticorrosive pigment, a pH adjuster, a plasticizer, a preservative, an antifungal agent, and an antifungal agent in addition to the main agent and/or curing agent. Algae agent, defoaming agent, leveling agent, dispersant, anti-settling agent, anti-sagging agent, thickener (thixotropic control agent), film-forming aid, matting agent, cross-linking agent, catalyst, curing accelerator, adhesion A property-imparting agent, an ultraviolet absorber, a light stabilizer, and the like can be mixed within a range in which the effects of the present invention are not significantly impaired. The pH of the aqueous coating material of the present invention is preferably 3-12 (more preferably 4-11). In addition, in the present invention, it is preferable that the pH of the main agent satisfies the above.

As the water-based coating material of the present invention, various materials such as colored or non-colored, opaque or transparent can be used. In the present invention, it can preferably be used as a transparent clear-type aqueous coating material. The aqueous coating material of the present invention preferably has a solid content of 5 to 60% by weight (more preferably 6 to 50% by weight, still more preferably 7 to 45% by weight). The solid content can be adjusted by mixing the aqueous medium. In the case of such a range, the coating workability is excellent, and the adhesion to various substrates and coating films can be further improved.

Furthermore, the gel fraction of the film formed from the water-based coating material of the present invention is preferably 25% or more (more preferably 30% or more, still more preferably 35% or more). Although the upper limit is not particularly limited, it is practically preferably 95% or less (more preferably 90% or less). When the formed coating satisfies such a range, the effects of the present invention can be sufficiently exhibited, and the physical properties of the coating such as water resistance and solvent resistance can be further enhanced. As a result, it is possible to ensure sufficient adhesion to existing coating films and various topcoat materials (water-based, weakly solvent-based). In particular, even when a weak solvent-based topcoat material is used, sufficient adhesion can be exhibited and lifting resistance can be enhanced.

In the present invention, the gel fraction is tested by applying an aqueous coating material on a polyester film to a coating thickness of 0.5 mm and drying at 23 ° C. for 24 hours to form a coating. It is calculated by the following formula after making a piece and immersing it in acetone for 24 hours.
Gel fraction (%) = (coat weight after immersion/coat weight before immersion) x 100

<Coating method>
The water-based coating material of the present invention is suitably used as an undercoat material for coating interior and exterior wall surfaces, floor surfaces, and the like. For example, base materials such as mortar, concrete, ceramic siding board, ceramic siding board, metal siding board, extrusion board, slate board, calcium silicate board, ALC board, metal, wood, glass, ceramics, synthetic resin, etc. Alternatively, it can be suitably used as an undercoat material applied to undercoats such as a wide variety of existing coating films formed on such substrates (surfaces of substrates). In addition, the shape of such a substrate (base material or existing coating film) can be smooth (flat) or various uneven patterns (e.g., stone tone, brick/tile tone, wood grain tone, border tone, painted wall tone, blown wall tone, etc.). (additional tone, etc.). Furthermore, it can also be applied to substrates including sealing joints.

In particular, the aqueous coating material of the present invention is suitable as an undercoat material for repairing a base, and can be suitably applied, for example, as a undercoat material when repairing a base such as a siding board provided with an existing coating film.

Existing coatings are various coatings that have already been applied on the above base material by on-site coating or factory coating (line coating), for example, organic coatings, inorganic coatings, and organic-inorganic composite coatings. and at least one coating film selected from In addition, existing coatings include colored coatings (enamel-based coatings, printed coatings, etc.), clear coatings, and laminated coatings of these. This is the formed coating film. Such a coating material may be of a room temperature drying type, a room temperature curing type, a baking curing type, an ultraviolet (UV) curing type, an electron beam curing type, or the like.

Examples of binders for such coating materials include organic binders such as acrylic resins, polyurethane resins, epoxy resins, fluorine resins, alkyd resins, and polyester resins, silicone resins, alkoxysilanes, colloidal silica, silicates, and the like. and organic/inorganic composite binders such as acrylic silicone resins.

In the present invention, in particular, the existing coating film is an inorganic coating film (a coating film containing the above-mentioned inorganic binder), an organic-inorganic composite coating film (a coating film containing the above-mentioned organic-inorganic composite binding material), a fluororesin coating film (the above-mentioned fluorine resin-containing coating film), etc., and can be suitably applied to these clear coating films. Such an existing coating film may contain photocatalytic titanium oxide or the like.

Specific coating materials include, for example, weather-resistant finish paint for construction (JIS K5658: 2010), weather-resistant paint for steel structures (JIS K5659: 2008), glossy synthetic resin emulsion paint (JIS K5660: 2008), Fireproof paint for construction (JIS K5661: 1970), synthetic resin emulsion paint (JIS K5663: 2008), road marking paint (JIS K5665: 2011), colorful pattern paint (JIS K5667: 2003), synthetic resin emulsion paint (JIS K5668: 2010), acrylic resin-based non-aqueous dispersion paint (JIS K5670: 2008), lead- and chromium-free anticorrosive paint (JIS K5674: 2008), high solar reflectance paint for roofs (JIS K5675: 2011), for buildings Floor coatings (JIS K5970:2008), architectural coating film waterproofing materials (JIS A6021:2011), architectural finishing coating materials (JIS A6909:2014), and the like.

As a method of forming a film using the aqueous coating material of the present invention as an undercoat material, for example,
A method of forming a coating by applying an undercoat material to a base material and then applying a topcoat material to the base material, and a method using the aqueous coating material of the present invention as the undercoat material. As a result, it is possible to form a coating excellent in adhesion to various substrates and topcoat materials.

Various methods such as brush coating, roller coating, and spray coating can be employed for coating the water-based coating material of the present invention. In the case of coating in a factory, it is also possible to use a roll coater, a flow coater, or the like, in addition to the above.

The coating amount of the water-based coating material is preferably about 0.05 to 0.5 kg/m ² (more preferably 0.07 to 0.3 kg/m ² ). The number of times the water-based coating material is applied may be appropriately set depending on the state of the substrate, but is preferably 1 to 2 times. The drying time of the water-based coating material is preferably from 1 hour to 1 week. The drying temperature is preferably -10°C or higher and 50°C or lower, more preferably -5°C or higher and 40°C or lower. The water-based coating material of the present invention is preferable as a room temperature curing type.

The gel fraction of the film formed by the above method is preferably 25% or more (preferably 30% or more, more preferably 35% or more). Although the upper limit is not particularly limited, it is practically preferably 95% or less (more preferably 90% or less). When the formed coating satisfies such a range, it is possible to ensure excellent adhesion to the base material and a wide variety of topcoat materials. The method for calculating the gel fraction is as described above.

The topcoat material is not particularly limited as long as it is generally used for painting of buildings, and the binder includes, for example, acrylic resin, polyurethane resin, epoxy resin, fluororesin, and alkyd resin. , polyester resins and the like; inorganic binders such as silicone resins, alkoxysilanes, colloidal silica and silicates; and organic-inorganic composite binders such as acrylic silicone resins. In particular, in the present invention, it is possible to sufficiently exhibit adhesion to a topcoat material containing one or more selected from the organic binder and the organic-inorganic composite binder. In addition, the form of the topcoat material may be any of a water-based topcoat material, a solvent-based (weak solvent-based) topcoat material, and the like.

Specific topcoat materials include, for example, weather-resistant topcoat paint for construction (JIS K5658: 2010), weather-resistant paint for steel structures (JIS K5659: 2008), glossy synthetic resin emulsion paint (JIS K5660: 2008), Fireproof paint for construction (JIS K5661: 1970), synthetic resin emulsion paint (JIS K5663: 2008), road marking paint (JIS K5665: 2011), colorful pattern paint (JIS K5667: 2003), synthetic resin emulsion paint (JIS K5668: 2010), acrylic resin-based non-aqueous dispersion paint (JIS K5670: 2008), lead- and chromium-free anticorrosive paint (JIS K5674: 2008), high solar reflectance paint for roofs (JIS K5675: 2011), for buildings Floor coatings (JIS K5970:2008), architectural coating film waterproofing materials (JIS A6021:2011), architectural finishing coating materials (JIS A6909:2014), and the like.

The method of coating the topcoat material is not particularly limited, and it can be coated by a known method, for example, brush coating, trowel coating, spray coating, roller coating, roll coater, flow coater, etc. can be done. That is, each topcoat material may be coated based on the usual process with the optimum coating specifications (number of coatings, drying temperature, etc.) for each topcoat material. The drying temperature is preferably -10°C or higher and 50°C or lower, more preferably -5°C or higher and 40°C or lower. The film forming method of the present invention is preferable as a room temperature curing type.

Examples and comparative examples are shown below to further clarify the features of the present invention.

<Production of main ingredients 1 to 15>
Epoxy resin emulsion (A), acrylic resin emulsion (C), organic solvent (D), silane compound (S), catalyst (P), additives, and water were mixed at the mixing ratios shown in Table 1, and main agent 1 ~15.

<Production of Curing Agents 1 and 2>
The amino group-containing resin (B1) was used as curing agent 1.
A curing agent 2 was prepared by mixing the amino group-containing resin (B1) and the amino group-containing silane compound (S3) at a weight ratio of 3:7.

In addition, the following were used as a raw material.
・Epoxy resin emulsion (A)
(A1) Epoxy resin emulsion [Bisphenol A type epoxy resin (solid type) aqueous dispersion, solid content 46% by weight, average particle size: 390 nm, epoxy equivalent x _a 508]
- Amino group-containing resin (B)
(B1) Polyamine resin [water-soluble type, styrene addition reaction product of meta-xylenediamine, solid content 100% by weight, active hydrogen equivalent _yb : 103]
・Acrylic resin emulsion (C)
(C1) Acrylic resin emulsion [styrene/2-ethylhexyl acrylate/glycidyl methacrylate copolymer, glass transition temperature: 20°C, solid content: 33% by weight, glycidyl methacrylate content: 9% by weight, average particle size: 75 nm]
(C2) Acrylic resin emulsion [styrene/2-ethylhexyl acrylate/glycidyl methacrylate copolymer, glass transition temperature: 3°C, solid content: 33% by weight, glycidyl methacrylate content: 9% by weight, average particle size: 120 nm]
(C3) Acrylic resin emulsion [styrene/2-ethylhexyl acrylate/glycidyl methacrylate copolymer, glass transition temperature: -3°C, solid content: 33% by weight, glycidyl methacrylate content: 9% by weight, average particle size: 160 nm]
(C4) acrylic silicone resin emulsion [methyl methacrylate/n-butyl acrylate/glycidyl methacrylate/3-methacryloyloxypropyltrimethoxysilane/acrylic acid copolymer, glass transition temperature: 20° C., solid content: 33% by weight, alkoxysilyl Group-containing monomer content: 1% by weight, glycidyl methacrylate content: 2% by weight, average particle size: 120 nm]
(C5) Acrylic resin emulsion [styrene/2-ethylhexyl acrylate/methacrylate copolymer, glass transition temperature: 20°C, solid content: 33% by weight, average particle size: 75 nm]
・Organic solvent (D)
(D1) Dipropylene glycol-n-butyl ether [boiling point 229°C, solubility in water at 20°C 5g/100g H ₂ O]
(D2) 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate [boiling point 2853° C., solubility in water at 20° C. 0.09 g/100 g H ₂ O]
(D3) Propylene glycol [boiling point 187°C, water solubility ∞ at 20°C]
・Silane compound (S)
(S1) Glycidyl group-containing silane compound [β-3,4-epoxycyclohexylethyltrimethoxysilane, epoxy equivalent x _n1 : 246]
(S2) Alkylalkoxysilane compound [phenyltrimethoxysilane/dimethoxymethylphenylsilane mixture]
(S3) Amino group-containing silane compound [N-β (aminoethyl)-γ-aminopropylmethyldimethoxysilane, active hydrogen equivalent y _m : 103]
・Catalyst (P)
(P1) Organotin compound dispersion [solid content: 10% by weight]
・Additives: Defoamers, thickeners, etc.

(Examples 1 to 26, Comparative Examples 1 to 4)
The main agent 1 shown in Table 1, the curing agent 1 or the curing agent 2, the epoxy equivalent ([X _A ]: solid content conversion value) of the (A) component in the main agent, and the activity of the (B) component in the curing agent Using an aqueous coating material (clear type aqueous coating material) mixed so that the hydrogen equivalent ([Y _B ]; solid content conversion value) ratio [ _{XA / (Y B )} ] = 1.0, An evaluation was carried out. Tables 2 and 3 show the combinations of the main agent and the curing agent.

<Water resistance evaluation>
As an existing coating film, a water-based coating material obtained by mixing a main agent and a curing agent was applied to a black acrylic plate (150 mm x 200 mm x 3 mm) immediately after mixing so that the coating thickness was 0.15 mm. A specimen [I] was prepared by drying for one day under the conditions (temperature: 23°C, relative humidity: 50%). After each specimen was immersed in water at 20°C for 48 hours, the specimen was taken out and dried (23°C, 3 hours), and the state of the coating film was visually observed for swelling, peeling, whitening, etc. evaluated.
The evaluation criteria were 6-grade evaluation (AA>A>AB>B>C>D), with "A" indicating almost no abnormality and "D" indicating abnormality. Results are shown in Tables 2 and 3.

<Adhesion evaluation 1>
(Preparation of test body)
・ Specimen [II]
A water-based coating material (clear-type water-based coating material) obtained by mixing a main agent and a curing agent in the combination shown in Table 3 was applied onto a siding board having an inorganic clear coating film formed thereon as an existing coating film in an amount of 0.00. Apply immediately after mixing to 1 kg / m ² , dry for 4 hours under standard conditions (temperature 23 ° C., relative humidity 50%), and then apply a water-based topcoat material (acrylic silicone resin emulsion paint). A specimen [I] was prepared by applying the composition so as to obtain .1 kg/m ² and drying for 1 day in an environment of 50°C.

Adhesion of the prepared test piece [I] was evaluated by the cross-cut tape method according to JIS K 5600-5-6. The results are shown in Tables 2 and 3.
Evaluation criteria are as follows.
AA: less than 5% defect area A: 5% or more and less than 10% defect area AB: 10% or more and less than 25% defect area B: 25% or more and less than 40% defect area C: defect area is 40% or more and less than 55% D: defect area is 55% or more

In Examples 1 to 26, good results were obtained in water resistance evaluation. Furthermore, in Examples 14 to 26, excellent results were obtained in the adhesion evaluation 1 as well.

Next, for Examples 14 to 26, the following specimens were prepared, and adhesion evaluation 2 and adhesion evaluation 3 were performed.
<Adhesion evaluation 2>
(Preparation of test body)
・ Specimen [III] to [V]
On the siding board on which the inorganic clear coating film was formed as the existing coating film, the water-based coating material was applied immediately after mixing so that the coating amount was 0.1 kg / m ² , and the standard conditions (temperature 23 ° C., relative humidity 50%) for 4 hours, then apply a water-based topcoat material (acrylic silicone resin emulsion paint) so that the coating amount is 0.1 kg / m ² , and dry for 1 day under standard conditions. [III], a specimen [IV] dried for 4 days, and a specimen [V] dried for 7 days were prepared.
Adhesion of the prepared specimens [III] to [V] was evaluated in the same manner as for the specimen [I]. The results are shown in Table 3.

<Adhesion evaluation 3>
(Preparation of test body)
・ Specimen [VI]
On a siding board on which an inorganic clear coating film has been formed as an existing coating film, the water-based coating material is applied immediately after mixing so that the coating amount is 0.1 kg / m ² and dried in an environment of 23 ° C. for 7 days. Next, a water-based topcoat material (acrylic silicone resin emulsion paint) was applied at a coating amount of 0.1 kg/m ² and dried under standard conditions for 1 day to prepare a specimen [VI].
・ Specimen [VII]
On a siding board on which an inorganic clear coating film has been formed as an existing coating film, the water-based coating material is applied immediately after mixing so that the coating amount is 0.1 kg / m ² and dried in an environment of 5 ° C. for 7 days. Next, a water-based topcoat material (acrylic silicone resin emulsion paint) was applied at a coating amount of 0.1 kg/m ² and dried under standard conditions for 1 day to prepare a specimen [VII].
Adhesion of the prepared specimens [VI] and [VII] was evaluated in the same manner as for the specimen [I]. The results are shown in Table 3.

<Adhesion evaluation 4>
(Preparation of test body)
・ Specimen [VIII]
Example 19 [main agent 6 (gel fraction of component (C5): 0%) and curing agent 2], Example 23 [main agent 10 (( The gel fraction of component C2): 70%) and the aqueous coating material (clear type aqueous coating material) of curing agent 2) were applied immediately after mixing so that the coating amount was 0.1 kg / m ² , and the standard condition It was dried for 4 hours at a temperature of 23° C. and a relative humidity of 50%. Next, a weak solvent-based topcoat material (acrylic silicone resin paint) is applied so that the coating amount is 0.1 kg / m ² , and after drying and curing for 24 hours in a 23 ° C environment, the same weak solvent topcoat material is applied. Specimen [VIII], which was applied in an amount of 0.1 kg/m ² , was visually evaluated for its appearance, and its adhesion was evaluated in the same manner as for Specimen [I].
As a result, in Example 19 (the gel fraction of the formed film: 25%), a lifting phenomenon (shrinkage) was observed, and the adhesion was "C". On the other hand, in Example 23 (the gel fraction of the formed film: 60%), no abnormalities were observed in the film, and the adhesion was "AA".

Claims (3)

An aqueous coating material having a main agent containing an epoxy resin emulsion (A) and a curing agent containing an amino group-containing resin (B),
The aqueous coating material contains an acrylic resin emulsion (C),
A water-based coating material, wherein the mixing weight ratio (solid content) of the epoxy resin emulsion (A) and the acrylic resin emulsion (C) is (A)/(C)<1. 2. The water-based coating material according to claim 1, wherein the acrylic resin emulsion (C) is a polymer of a monomer group containing an epoxy group-containing monomer. 3. The composition according to claim 1, further comprising an organic solvent (D) having a boiling point of 200° C. or higher and a solubility in water of 10 g/100 g H ₂ O or lower at 20° C. Aqueous coating.