Water-based covering materials

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

[Technical Field]

[0001] The present invention relates to a novel water-based coating material. [Background technology]

[0002] When painting interior and exterior walls and floors of buildings, various primers are selected and used taking into consideration adhesion to the substrate. While such primers have traditionally been solvent-based, water-based primers have recently been adopted in consideration of the environment, safety, and other factors. For example, Patent Document 1 describes a two-component reactive curing water-based paint composition for primer paint, which consists of a base agent containing an epoxy resin emulsion and a curing agent containing an amine resin.

[0003] However, water-based primers may have poorer adhesion than solvent-based primers. In particular, in recent years, exterior building materials used on exterior wall surfaces have been provided with various coating films with high weather resistance, stain resistance, and other functionalities. When repairing such coating films, water-based primers may be difficult to achieve sufficient adhesion. Furthermore, epoxy resin-based primers may experience problems such as reduced adhesion due to amine blushing or whitening of the coating film under painting conditions such as low temperature or high humidity, and these problems tend to be more pronounced in water-based primers than in solvent-based primers. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-53028 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been made in view of these problems, and aims to provide an aqueous coating material that can ensure sufficient adhesion to various substrates and coating films under various coating conditions. [Means for solving the problem]

[0006] As a result of extensive research into these problems, the inventors discovered an aqueous coating material in which an acrylic resin emulsion is mixed in a specific weight ratio with an aqueous coating material having a base agent containing an epoxy resin emulsion and a curing agent containing an amino group-containing resin, and completed the present invention.

[0007] That is, the present invention has the following features. 1. An aqueous coating material having a base 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) and the acrylic resin emulsion (C) is (A) / (C)<1. the law of nature, Furthermore, it has a boiling point of 200°C or higher and a solubility in water at 20°C of 10g / 100gH 2 Contains the following organic solvents (D): An aqueous coating material characterized by: 2. The aqueous coating material according to 1., wherein the acrylic resin emulsion (C) is a polymer of a monomer group including an epoxy group-containing monomer. [Effects of the Invention]

[0008] The aqueous coating material of the present invention inhibits deterioration of adhesion and whitening of the coating film due to coating conditions, and exhibits excellent adhesion to a variety of substrates and coating films. DETAILED DESCRIPTION OF THE INVENTION

[0009] The present invention relates to an aqueous coating material (hereinafter also simply referred to as "aqueous coating material") having a base agent containing an epoxy resin emulsion (A) and a curing agent containing an amino group-containing resin (B).

[0010] The epoxy resin emulsion (A) of the present invention (hereinafter also referred to simply as "component (A)") is obtained by dispersing and emulsifying an epoxy resin in an aqueous medium. When dispersing an epoxy resin in an aqueous medium, an emulsifier or the like can be used as needed. The aqueous medium is a medium containing mainly water, and may contain a water-soluble solvent such as a lower alcohol, a polyhydric alcohol, an ether compound, an ester compound, or an alkylene oxide-containing compound, as needed.

[0011] The epoxy resin of component (A) may be either a solid epoxy resin or a liquid epoxy resin, as long as it is dispersible in an aqueous medium. Examples of such epoxy resins include resins containing one or more, preferably two or more, epoxy groups in the molecule, such as aromatic epoxy resins, aliphatic epoxy resins, alicyclic epoxy resins, polybutadiene resins containing epoxy groups, and polyurethane resins containing epoxy groups. In the present invention, aromatic epoxy resins are preferred, such as bisphenol A epoxy resins, bisphenol AD ​​epoxy resins, bisphenol F epoxy resins, and novolac epoxy resins. Of these, at least one selected from bisphenol A epoxy resins, bisphenol AD ​​epoxy resins, and bisphenol F epoxy resins is particularly preferred. Furthermore, the epoxy resin may be one whose molecular weight has been increased as needed, or one obtained by hydrolyzing a fatty acid-modified epoxy resin obtained by reacting a fatty acid, or an amine-added epoxy resin (amine-modified epoxy resin) obtained by the addition reaction of an amino group-containing compound. These resins may be used alone or in combination of two or more. A solid epoxy resin is one that is solid at room temperature (23°C), and a liquid epoxy resin is one that is liquid at room temperature (23°C).

[0012] In the present invention, a preferred embodiment is one in which 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 both the solid epoxy resin (a1) and the liquid epoxy resin (a2). This allows the effects of the present invention to be fully achieved. When the solid epoxy resin (a1) and the liquid epoxy resin (a2) are mixed, the mixing ratio (solids weight ratio) is preferably 100:0 to 5:95 (more preferably 100:0 to 10:90), depending on the epoxy equivalent of each epoxy resin. In the present invention, "α to β" is synonymous with "α or more and β or less."

[0013] The method for preparing component (A) is not particularly limited, but examples include a method in which a solid epoxy resin and / or a liquid epoxy resin is mixed with an emulsifier, if necessary, to prepare a resin solution, and then the solution is mixed with an aqueous medium (containing an emulsifier, if necessary) to emulsify it. Heating may be performed as necessary during the preparation. In the present invention, when a solid epoxy resin and a liquid epoxy resin are used in combination, it is preferred to prepare aqueous dispersions of the solid epoxy resin and the liquid epoxy resin separately and then mix them for 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).

[0014] As the emulsifier, for example, anionic surfactants and nonionic surfactants can be used either alone or in combination. Examples of anionic surfactants include alkali metal sulfonates such as sodium dodecylbenzenesulfonate, sodium laurylnaphthalenesulfonate, and sodium stearyldiphenyletherdisulfonate; and alkali metal sulfates such as sodium lauryl sulfate, polyoxyethylene lauryl ether sodium sulfate, and polyoxyethylene octylphenyl ether sodium sulfate. 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 emulsifier to be added is preferably within the range of 0.1 to 15% by weight (more preferably 0.1 to 10% by weight, and even more preferably 0.5 to 5% by weight) based on the resin solid content.

[0015] 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, even more preferably 200 to 800 nm, and particularly preferably 300 to 600 nm). If the average particle size is within this range, advantageous effects can be obtained in terms of sealing properties, efflorescence resistance, whitening resistance, etc. The average particle size referred to here is a value measured by dynamic light scattering.

[0016] The component (A) of the present invention has an epoxy equivalent weight x a is preferably 100 to 3000 (more preferably 110 to 2000, and even more preferably 120 to 1500). a " is the number of grams of resin solids containing 1 gram equivalent of epoxy groups [g / eq], and is the value obtained by dividing the weight average molecular weight of the epoxy resin by the number of epoxy groups per molecule.

[0017] The component (A) has an epoxy equivalent x a It is also possible to use a mixture of particles having different particle sizes and average particle diameters.

[0018] The amino group-containing resin (B) of the present invention (hereinafter simply referred to as "component (B)") reacts with the epoxy resin emulsion (A) to form a coating film. Examples of such component (B) include polyamine resins containing two or more amino groups per molecule, such as aliphatic polyamines, alicyclic polyamines, aromatic polyamines, heterocyclic amines, and modified polyamine resins obtained by modifying the amino groups of these polyamine resins. The polyamine resins can be modified by known methods, such as amidation of amino groups, the Mannich reaction of amino groups with carbonyl compounds, the addition reaction of amino groups with epoxy groups, and the addition reaction of amino groups with styrene. Other examples of component (B) that can be used include aliphatic polyamides, alicyclic polyamides, aromatic polyamides, aliphatic polyamidoamines, alicyclic polyamidoamines, and aromatic polyamidoamines. These can be used alone or in combination.

[0019] In the present invention, the component (B) preferably contains at least one selected from aliphatic polyamines and modified aliphatic polyamines. This improves adhesion and adhesion to substrates and coatings when mixed with a base resin containing an epoxy resin emulsion. Examples of aliphatic polyamines include linear aliphatic polyamines such as diethylenetriamine, triethylenetetraamine, tetraethylenepentamine, dipropylenediamine, diethylaminopropylamine, and hexamethylenediamine; cyclic aliphatic polyamines such as N-aminoethylpiperazine, bis(4-amino-3-methylcyclohexyl)methane, menthenediamine, isophoronediamine, 4,4'-diaminodicyclohexylmethane, 3,9-bis(3-aminopropyl)-2,4,8,10-tetraoxaspiro[5.5]undecane (spiroacetaldiamine), norbornanediamine, tricyclodecanediamine, and 1,3-bisaminomethylcyclohexane; and aliphatic aromatic amines such as metaxylenediamine. In the present invention, it is particularly preferable to contain at least one selected from metaxylenediamine and styrene addition reaction products of metaxylenediamine.

[0020] The form of component (B) is not particularly limited, but water-soluble resins that can be dissolved in aqueous media or water-dispersible resins that can be dispersed in aqueous media can be used. In the present invention, it is preferable that component (B) contains a water-soluble resin. In this case, not only is storage stability excellent, but when mixed with the base resin, compatibility and reactivity with the epoxy resin emulsion (A) are enhanced, further improving adhesion and adhesion to substrates and coating films, and forming coating films with excellent water resistance and coating appearance. Component (B) may be solvent-free (solid content 100% by weight) or may be pre-dissolved or dispersed in an aqueous medium. The solid content of component (B) is preferably 50% by weight or more (more preferably 55% by weight or more, and even 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 met, the effects of the present invention can be fully exhibited. The aqueous medium is a medium that mainly contains water, and may contain water-soluble solvents such as lower alcohols, polyhydric alcohols, ether compounds, ester compounds, and alkylene oxide-containing compounds, as needed.

[0021] In addition, the active hydrogen equivalent y of the component (B) is b is preferably 10 to 1000 (more preferably 50 to 800, and even more preferably 80 to 600). b " is the number of grams [g / eq] of resin solids containing 1 gram equivalent of active hydrogen groups, and is the value obtained by dividing the weight average molecular weight of the amino group-containing resin by the number of hydrogen atoms of the amino group per molecule.

[0022] The aqueous coating material of the present invention is a mixture of the base agent and the curing agent in an amount of 1000 ppm or less based on the epoxy equivalent ([X A ]: solid content equivalent) and the active hydrogen equivalent of component (B) in the curing agent ([Y B ]; solid content equivalent) ratio [X A / (Y BIt is preferable to mix them so that the ratio (ratio of the total weight of the aqueous coating material to the total weight of the coating material) is preferably 0.1 to 3 (more preferably 0.5 to 2, and even more preferably 0.7 to 1.5). In such a case, the adhesion and adhesion of the aqueous coating material to the substrate and the coating film are improved. Furthermore, the stability and usable life of the aqueous coating material can be increased.

[0023] In addition, the above X A , the above Y B is determined from the number of blended parts at the time of mixing, and specifically, the above [X A ] is the amount of component (A) contained in the base resin (solid weight parts) multiplied by the epoxy equivalent of component (A) x a The value is divided by the above [Y B ] is the amount of component (B) contained in the curing agent (parts by weight of solids) divided by the active hydrogen equivalent y of component (B). b This is the value divided by .

[0024] The curing agent of the present invention contains the above-mentioned component (B), and its solids content is preferably 10% by weight or more (more preferably 15% by weight, and even more preferably 20% by weight). The upper limit of the solids content is 100% by weight or less. When this range is satisfied, the effects of the present invention can be fully exhibited. The solids content can be adjusted by mixing the above-mentioned aqueous medium. Specifically, the aqueous medium in the curing agent may be mixed during the production of the curing agent, or may be included as a medium for the above-mentioned component (B). 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, and even more preferably 10% by weight or less), and embodiments in which the curing agent is substantially free of water are also suitable. When this range is satisfied, the storage stability of the curing agent can be fully exhibited, and the activity of the above-mentioned component (S3) can be enhanced. When mixed with the main agent, this can further improve the adhesion and adhesion to substrates and coating films.

[0025] The aqueous coating material of the present invention is characterized by containing, in addition to the above-mentioned components (A) and (B), an acrylic resin emulsion (C) (hereinafter also referred to simply as "component (C)"), and by having a weight ratio (solids content) of component (A) to component (C) of (A) / (C)<1 (preferably <0.9, more preferably <0.8). The lower limit of this ratio is not particularly limited as long as component (A) is included, but is preferably 0.1<(A) / (C) (more preferably 0.2<). By including component (C) at such a ratio, the concentration of component (C) tends to be higher near the surface of the formed coating film. This results in reduced influence from coating conditions, excellent adhesion to various substrates and coatings, and particularly improved adhesion to existing coatings and topcoats. Furthermore, coatings with excellent water resistance and appearance can be formed.

[0026] The above-mentioned component (C) can be mixed with either the base resin or the curing agent, or both, but in the present invention it is preferable to mix it with the base resin, which further enhances the above-mentioned effects and enables the formation of a coating film with excellent appearance in which amine blushing and other problems are suppressed.

[0027] The component (C) is a copolymer of (meth)acrylic acid alkyl ester as the main component of the resin skeleton and, if necessary, other monomers or other polymerizable monomers. In the present invention, the alkyl acrylate and alkyl methacrylate are collectively referred to as (meth)acrylic acid alkyl ester. Furthermore, the term "monomer" is a general term for compounds having a polymerizable unsaturated double bond.

[0028] In the present invention, it is preferable that the group of monomers constituting component (C) contains a hydrophobic monomer, such as a long-chain alkyl (meth)acrylate or an aromatic group-containing monomer.

[0029] 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, n-hexyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, octyl(meth)acrylate, decyl(meth)acrylate, dodecyl(meth)acrylate, octadecyl(meth)acrylate, cyclohexyl(meth)acrylate, etc. These can be used alone or in combination of two or more.

[0030] Examples of aromatic group-containing monomers include styrene-based monomers such as styrene, 2-methylstyrene, vinyltoluene, ethylvinylbenzene, vinylnaphthalene, and chlorostyrene, and aromatic group-containing (meth)acrylates such as phenyl(meth)acrylate, benzyl(meth)acrylate, and phenoxyethyl(meth)acrylate. These may be used alone or in combination of two or more.

[0031] In the present invention, a particularly preferred embodiment is one in which the hydrophobic monomer contains an alkyl(meth)acrylate having an alkyl group with 6 or more carbon atoms (preferably 8 or more carbon atoms).

[0032] The content of the hydrophobic monomer in the monomer group is preferably 10% by weight or more, more preferably 30% by weight or more, and even more preferably 40% by weight or more. There is no particular upper limit, but it is preferably 99.5% by weight or less. In this case, compatibility with the organic solvent (D) described below is improved, thereby enhancing the effects of the present invention.

[0033] 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, alkoxysilyl group-containing monomers, ethylene, propylene, isoprene, butadiene, vinyl ether, vinyl ketone, etc. These can be used alone or in combination of two or more.

[0034] In the present invention, it is preferable to contain an epoxy group-containing monomer. Examples of epoxy group-containing monomers include glycidyl (meth)acrylate, diglycidyl fumarate, 3,4-epoxycyclohexyl (meth)acrylate, 3,4-epoxyvinylcyclohexane, allyl glycidyl ether, ε-caprolactone-modified glycidyl (meth)acrylate, and β-methylglycidyl (meth)acrylate. These can be used alone or in combination of two or more.

[0035] In the present invention, the content of the epoxy group-containing monomer in the monomers constituting component (C) is preferably 0.5 to 50% by weight (more preferably 1 to 30% by weight), which prevents deterioration of adhesion and whitening of the coating film due to amine blushing, and allows the coating film to exhibit sufficient physical properties.

[0036] Specific examples of other monomers include: Examples of nitrile group-containing monomers include (meth)acrylonitrile, vinylidene cyanide, and α-cyanoethyl (meth)acrylate. Examples of the amide group-containing monomer 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, and vinylamide. Examples of the carbonyl group-containing monomer include acrolein, diacetone (meth)acrylamide, vinyl methyl ketone, vinyl ethyl ketone, and vinyl butyl ketone. Examples of carboxyl group-containing monomers include (meth)acrylic acid, crotonic acid, maleic acid, itaconic acid, fumaric acid, isocrotonic acid, and salicylic acid. Examples of amino group-containing monomers include aminomethyl acrylate, aminoethyl acrylate, aminopropyl (meth)acrylate, amino-n-butyl (meth)acrylate, butylvinylbenzylamine, vinylphenylamine, p-aminostyrene, N-methylaminoethyl (meth)acrylate, and Nt-butylaminoethyl (meth)acrylate. Examples of hydroxyl group-containing monomers include hydroxypropyl (meth)acrylate, ethylene glycol mono(meth)acrylate, and glycerol mono(meth)acrylate. Examples of vinylidene halide monomers include vinylidene fluoride, Examples of alkoxysilyl group-containing monomers include vinyltrimethoxysilane, vinyltriethoxysilane, γ-(meth)acryloyloxypropyltrimethoxysilane, γ-(meth)acryloyloxypropyltriethoxysilane, γ-(meth)acryloyloxypropylmethyldimethoxysilane, etc. These can be used alone or in combination of two or more.

[0037] The component (C) can be produced by emulsion polymerization of a suitable mixture of the above monomers. Any known polymerization method can be used, including conventional emulsion polymerization, soap-free emulsion polymerization, feed emulsion polymerization, seed emulsion polymerization, and multi-stage emulsion polymerization. During polymerization, for example, emulsifiers, initiators, dispersants, polymerization inhibitors, polymerization retarders, buffers, chain transfer agents, and pH adjusters can be used.

[0038] As the emulsifier, various surfactants that can be used in emulsion polymerization can be used, and these may be reactive types (reactive surfactants) having polymerizable unsaturated double bonds. As the emulsifier, for example, anionic surfactants and nonionic surfactants can be used alone or in combination. Specifically, they can be appropriately selected from those described above for component (A).

[0039] The glass transition temperature (hereinafter simply referred to as "Tg") of the component (C) can be adjusted by selecting the type and mixing ratio of the monomers. This Tg can be set appropriately taking into consideration the final required performance, etc., but it is preferable that the Tg is greater than -8°C and not greater than 80°C (more preferably, not less than -7°C and not greater than 60°C). Two or more components with different Tgs can also be used as component (C). In this case, it is preferable that the total Tg falls within the above range. The glass transition temperature can be calculated using the Fox formula.

[0040] The average particle size of the component (C) is not particularly limited, but is preferably 300 nm or less (more preferably 20 to 250 nm, and even more preferably 30 to 200 nm). If the average particle size is within this range, advantageous effects can be obtained in terms of impregnation reinforcement, sealing properties, efflorescence resistance, and whitening resistance. Two or more types of component (C) with different average particle sizes can also be used. The average particle size referred to here is a value measured by dynamic light scattering.

[0041] In the present invention, the ratio of the average particle sizes of the (A) component and the (C) component is preferably (A) / (C) > 1 (more preferably > 1.2). This tends to increase the concentration of the (C) component near the surface of the formed coating film, thereby suppressing the effects of coating conditions and enabling the development of even better coating film properties. When the (A) component and the (C) component contain two or more particles with different average particle sizes, it is preferable that the average value of the average particle size of the (A) component and the average value of the average particle size of the (C) component satisfy the above condition.

[0042] Furthermore, the gel fraction of the coating formed from the component (C) is preferably 10% or more (preferably 20% or more, more preferably 30% or more). There are no particular upper limits, but practically it is preferably 95% or less (more preferably 90% or less). When the coating formed from the component (C) satisfies this range, the above effects are enhanced and sufficient adhesion can be ensured.

[0043] In the present invention, the gel fraction is calculated by applying component (C) to a polyester film to a thickness of 0.5 mm, drying at 50°C for 3 days to form a coating, and using the resultant test piece as a coating. The test piece is then immersed in acetone for 24 hours, and the gel fraction is calculated using the following formula: Gel fraction (%) = (coating weight after immersion / coating weight before immersion) × 100

[0044] The method for adjusting the gel fraction is not particularly limited, and examples thereof include blending a chain transfer agent, copolymerizing a polyfunctional monomer or a monomer having a self-crosslinking functional group (such as a hydrolyzable silyl group-containing monomer or a methylol group-containing monomer), and copolymerizing a monomer having a functional group such as a carboxyl group, a hydroxyl group, an epoxy group, an amide group, a carbonyl group, or an acetoacetyl group, and adding a crosslinking agent capable of reacting with the functional group during and / or after the polymerization.

[0045] In the present invention, water-soluble resins and / or resin emulsions other than the above-mentioned components (A) and (C) can also be mixed in, as long as they do not impair the effects of the present invention. Examples of types of resins include acrylic resins (excluding the above-mentioned component (C)), urethane resins, silicone resins, fluororesins, vinyl acetate resins, polyester resins, alkyd resins, vinyl chloride resins, etc., as well as composites of these.

[0046] Furthermore, the aqueous coating material of the present invention preferably contains an organic solvent (D) (hereinafter simply referred to as "component (D)") having a boiling point of 200°C or higher and a solubility in water at 20°C of 10 g / 100 g H2O or less. The inclusion of component (D) in addition to component (C) enhances the compatibility and reactivity of components (A), (B), and (C), resulting in excellent film-forming properties. As a result, a dense coating film can be formed, the effects of coating conditions can be efficiently suppressed, and amine blushing and other problems are even less likely to occur.

[0047] The above-mentioned component (D) can be mixed with either the base agent or the curing agent, or both. In the present invention, the component (D) is preferably mixed with the base agent. This further enhances the above-mentioned effects, allowing the formation of a coating film with excellent aesthetics in which amine blushing and other problems are sufficiently suppressed.

[0048] The 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 10g / 100g / 100gH2O or less at 20°C, but examples include ethylene glycol ether compounds such as ethylene glycol monohexyl ether, ethylene glycol dibutyl ether, and ethylene glycol phenyl ether; diethylene glycol ether compounds such as diethylene glycol monohexyl ether, diethylene glycol monobutyl ether acetate, and diethylene glycol dibutyl ether; 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; 2-ethyl-1,3-hexanediol, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, 2,2,4-trimethyl-1,3-pentanediol diisobutyrate, and benzyl alcohol. These can be used alone or in combination of two or more. The boiling point of component (D) is 200°C or higher, with the upper limit being preferably 350°C or lower (more preferably 300°C or lower). The solubility of component (D) in water at 20°C is 10g / 100gH2O or lower, preferably 8g / 100gH2O or lower, with the lower limit being preferably 0g / 100gH2O or higher (more preferably 0.01g / 100gH2O or higher, even more preferably 0.05g / 100gH2O or higher, and particularly preferably 0.1g / 100gH2O or higher).

[0049] In the present invention, it is particularly preferred to contain at least one propylene glycol ether compound 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.

[0050] 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).Within this range, the above effects can be fully exhibited.

[0051] Furthermore, the aqueous coating material of the present invention may contain a silane compound (S). Examples of the silane compound (S) include a glycidyl group-containing silane compound (S1), an alkoxysilane compound (S2), and an amino group-containing silane compound (S3). These compounds may be used alone or in combination of two or more.

[0052] The glycidyl group-containing silane compound (S1) (hereinafter simply referred to as "component (S1)") may be a compound having a glycidyl group (epoxy group) and an alkoxysilyl group, or a compound having a glycidyl group and a cyclic siloxane. These may be used alone or in combination of two or more.

[0053] Examples of compounds having a glycidyl group (epoxy group) and an alkoxysilyl group include glycidyl group-containing silane coupling agents and hydrolyzed oligomers thereof.

[0054] Specific examples of glycidyl group-containing silane coupling agents include glycidoxymethyltrimethoxysilane, glycidoxymethyltriethoxysilane, β-glycidoxyethyltrimethoxysilane, β-glycidoxyethyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyldimethylmethoxysilane, γ-glycidoxypropyl(ethyl)dimethoxysilane, β-3,4-epoxycyclohexylethyltrimethoxysilane, β-3,4-epoxycyclohexylethyltriethoxysilane, 8-glycidoxyoctyltrimethoxysilane, 8-glycidoxyoctylmethyldimethoxysilane, and 8-glycidoxyoctylmethyldiethoxysilane, and preferably those having an epoxy equivalent of x n1 The epoxy equivalent weight x is 10 to 1000 (more preferably 50 to 500). n1 " is the number of grams [g / eq] of a silane compound containing 1 gram equivalent of epoxy groups, and is the value obtained by dividing the weight average molecular weight of a glycidyl group-containing silane compound by the number of epoxy groups per molecule.

[0055] The hydrolyzed oligomer of the glycidyl group-containing silane coupling agent has an alkoxysilyl group and a glycidyl group, and preferably has an alkoxy group content of 10 to 80 wt % (more preferably 20 to 75 wt %) and an epoxy equivalent x n1 The (N1) component may have two or more types of alkoxysilyl groups, or may have some or all of the alkoxysilyl groups in the form of silanol groups.

[0056] The compound having a glycidyl group and a cyclic siloxane is a silicone oligomer having only a glycidyl group as a reactive functional group, and preferably has an epoxy equivalent x n1is 100 to 500 (more preferably 150 to 400).

[0057] In particular, in the present invention, the above-mentioned component (S1) is preferably a glycidyl group-containing silane coupling agent. For example, one or more selected from glycidoxymethyltrimethoxysilane, glycidoxymethyltriethoxysilane, β-glycidoxyethyltrimethoxysilane, β-glycidoxyethyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, β-3,4-epoxycyclohexylethyltrimethoxysilane, and β-3,4-epoxycyclohexylethyltriethoxysilane are preferred. More preferred are embodiments containing one or more selected from β-3,4-epoxycyclohexylethyltrimethoxysilane and β-3,4-epoxycyclohexylethyltriethoxysilane. The use of these agents further improves adhesion and adhesion to substrates and coatings. Furthermore, the stability and usable life of the aqueous coating material can be increased.

[0058] When the component (S1) is contained, it is preferably mixed with the base material, and the mixing ratio is preferably 0.5 to 50 parts by weight (more preferably 1 to 40 parts by weight) of the component (S1) per 100 parts by weight of the component (A) (solid content). In this case, the adhesion to the substrate and coating film is enhanced, and the adhesion is further improved. Furthermore, the stability and usable life of the aqueous coating material can be increased.

[0059] The alkoxysilane compound (S2) (hereinafter simply referred to as "component (S2)") may be an alkoxysilane, a hydrolysis condensate thereof, or the like. These may be used alone or in combination of two or more. The use of such a component (S2) can further improve adhesion to the substrate.

[0060] Examples of such component (S2) include tetrafunctional alkoxysilane compounds such as tetraethoxysilane, tetramethoxysilane, tetra-n-propoxysilane, tetraisopropoxysilane, tetraisobutoxysilane, tetra-sec-butoxysilane, tetra-t-butoxysilane, and tetraphenoxysilane;

[0061] trifunctional alkylalkoxysilane compounds such as methyltrimethoxysilane, methyltriethoxysilane, methyltrippropoxysilane, methyltributoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltrippropoxysilane, ethyltributoxysilane, propyltrimethoxysilane, propyltriethoxysilane, propyltrippropoxysilane, propyltributoxysilane, butyltrimethoxysilane, butyltriethoxysilane, butyltrippropoxysilane, butyltributoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, decyltrimethoxysilane, trifluoropropyltrimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, and phenyltributoxysilane;

[0062] bifunctional alkylalkoxysilane compounds such as dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyldibutoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, diethyldibutoxysilane, diethyldipropoxysilane, dipropyldimethoxysilane, dipropyldiethoxysilane, dibutyldimethoxysilane, dibutyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, diphenyldibutoxysilane, dimethoxymethylphenylsilane, and methylphenyldiethoxysilane; These may be used alone or in combination of two or more.

[0063] In the present invention, the component (S2) preferably contains a trifunctional alkylalkoxysilane compound and / or a difunctional alkylalkoxysilane compound. It is further preferable to contain one containing a phenyl group. Examples of such component (S2) include phenyltrimethoxysilane, dimethoxymethylphenylsilane, diphenyldimethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, phenyltributoxysilane, and diphenyldibutoxysilane. The use of these compounds enhances the curability of the formed coating film, further improving its adhesion and adhesion to substrates and coating films. They are particularly effective in improving adhesion and adhesion to substrates with existing coating films.

[0064] When the component (S2) is contained, it can be mixed with either the base agent or the curing agent, or both, but in the present invention, it is preferably mixed with the base agent, and the mixing ratio is preferably 0.5 to 30 parts by weight (more preferably 1 to 20 parts by weight) of the component (S2) per 100 parts by weight of the component (A) (solid content). In such a case, the above-mentioned effects can be fully exhibited.

[0065] The amino group-containing silane compound (S3) (hereinafter simply referred to as "component (S3)") may be a compound having an amino group and an alkoxysilyl group, or a compound having an amino group and a cyclic siloxane. These may be used alone or in combination of two or more.

[0066] Examples of compounds having an amino group and an alkoxysilyl group include an amino group-containing silane coupling agent, a hydrolyzed oligomer thereof, and a polymer having an alkoxysilyl group and an amino group. Specific examples of the amino group-containing silane coupling agent include: 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-anilinopropyltrimethoxysilane, γ-ureidopropyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, N-vinylbenzyl-γ-aminopropyltriethoxysilane, N-β(aminoethyl)-8-aminooctyltrimethoxysilane, γ-triethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine, and the like.

[0067] As the hydrolyzed oligomer of the amino group-containing silane coupling agent, those having an alkoxysilyl group and an amino group can be used. As such component (S3), it is also possible to use one in which some or all of the alkoxysilyl groups have been converted into silanol groups.

[0068] In particular, in the present invention, as component (S3), an amino group-containing silane coupling agent is preferred, such as one or more selected from γ-aminopropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane, N-β(aminoethyl)-γ-aminopropylmethyldimethoxysilane, and N-β(aminoethyl)-γ-aminopropylmethyldiethoxysilane. When these are used, adhesion to substrates and coating films is improved.

[0069] In addition, the above component (S3) has an active hydrogen equivalent y mis preferably 10 to 500 (more preferably 20 to 400, and even more preferably 30 to 300). m " is the number of grams [g / eq] of an amino group-containing silane compound containing 1 gram equivalent of active hydrogen groups, and is the value obtained by dividing the weight-average molecular weight of the amino group-containing silane compound by the number of hydrogen atoms in the amino group per molecule.

[0070] When the component (S3) is contained, it is preferably mixed with a curing agent, and the mixing ratio is preferably 0.5 to 200 parts by weight (more preferably 1 to 100 parts by weight) of the component (S3) per 100 parts by weight of the component (A). When this range is satisfied, the storage stability is excellent, and when mixed with the main agent, the adhesiveness and adhesion to the substrate and coating film can be fully exhibited.

[0071] In the present invention, it is preferable to mix a catalyst (P) (hereinafter simply referred to as "component (P)") in the aqueous coating material. Component (P) promotes, for example, the reaction between glycidyl groups (epoxy groups) and amino groups in the aqueous coating material, or the hydrolysis and condensation of alkoxysilyl groups, thereby further improving adhesion to substrates, particularly to substrates with existing coating films.

[0072] 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; tertiary amines such as trimethylamine, ethyldimethylamine, propyldimethylamine, N,N'-dimethylpiperazine, pyridine, picoline, 1,8-diazabiscyclo(5,4,0)undecene-1 (DBU), benzyldimethylamine, 2-(dimethylaminomethyl)phenol (DMP-10), and 2,4,6-tris(dimethylaminomethyl)phenol (DMP-30); hydroxylamine, phenoxyamine, and other amines; Examples of the (B) component include imidazoles such as silamines, imidazole, 1-methylimidazole, 2-methylimidazole, 4(5)-methylimidazole, 2-ethyl-4-methylimidazole, 2-ethylimidazole, and 2-phenylimidazole; amines other than the (S3) component; phenols such as phenol novolak, o-cresol novolak, p-cresol novolak, t-butylphenol novolak, and dicyclopentadiene cresol; and organometallic compounds such as tin octoate, dibutyltin dilaurate, dibutyltin diacetate, organotitanate, and sodium acetate. These can be used alone or in combination of two or more. Among these, as component (P), particularly preferred are organotin compounds such as tin octoate, dibutyltin dilaurate, and dibutyltin diacetate; and various aromatic carboxylic acids such as benzoic acid, salicylic acid, trihydroxybenzoic acid, phthalic acid, cinnamic acid, and benzenehexacarboxylic acid.

[0073] The component (P) can be mixed with the base agent and / or curing agent, and the amount of the active ingredient of the component (P) is preferably 0.01 to 15 parts by weight (more preferably 0.02 to 10 parts by weight) per 100 parts by weight of the component (A) (solid content).Within this range, the effects of the present invention can be enhanced.

[0074] In addition to the above-mentioned components, the aqueous coating material of the present invention may contain color pigments, extender pigments, anti-rust pigments, pH adjusters, plasticizers, preservatives, antifungal agents, anti-algae agents, antifoaming agents, leveling agents, dispersants, anti-settling agents, anti-sagging agents, thickeners (thixotropic adjusters), film-forming aids, matting agents, crosslinking agents, catalysts, curing accelerators, adhesion promoters, UV absorbers, light stabilizers, etc., mixed into the base agent and / or curing agent as needed, provided that the effects of the present invention are not significantly impaired. The pH of the aqueous coating material of the present invention is preferably 3 to 12 (more preferably 4 to 11). In the present invention, it is preferable that the pH of the base agent satisfies the above range.

[0075] The aqueous coating material of the present invention can be various, such as colored or uncolored, opaque or transparent. In the present invention, it can be preferably used as a transparent clear aqueous coating material. The aqueous coating material of the present invention preferably has a solids content of 5 to 60% by weight (more preferably 6 to 50% by weight, and even more preferably 7 to 45% by weight). The solids content can be adjusted by mixing the above-mentioned aqueous medium. Within this range, excellent coating workability can be achieved, and adhesion to various substrates and coating films can be further improved.

[0076] Furthermore, the gel fraction of the coating formed by the aqueous coating material of the present invention is preferably 25% or more (more preferably 30% or more, even more preferably 35% or more). The upper limit is not particularly limited, but practically it is 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 fully exerted, and the coating film properties such as water resistance and solvent resistance can be further improved. This makes it possible to sufficiently ensure adhesion with existing coating films and various topcoats (water-based, weak solvent-based). In particular, even when using a weak solvent-based topcoat material, sufficient adhesion can be exerted and lifting resistance can be improved.

[0077] In the present invention, the gel fraction is calculated by applying the aqueous coating material to a polyester film to a thickness of 0.5 mm, drying it at 23°C for 24 hours to form a coating, and using the resulting test piece as a coating. The test piece is then immersed in acetone for 24 hours, and the gel fraction is calculated by the following formula: Gel fraction (%) = (coating weight after immersion / coating weight before immersion) × 100

[0078] <Film formation method> The aqueous coating material of the present invention is suitable for use as a primer for painting interior and exterior wall surfaces, floors, and the like. For example, it is suitable for use as a primer for application to substrates such as mortar, concrete, ceramic siding boards, ceramic siding boards, metal siding boards, extruded boards, slate boards, calcium silicate boards, ALC boards, metals, wood, glass, ceramics, and synthetic resins, as well as a wide variety of existing coating films formed on such substrates (surfaces of the substrates). The shape of such substrates (substrates and existing coating films) can be smooth (flat) or have various textured patterns (e.g., stone, brick, tile, wood grain, border, plaster, sprayed, etc.). Furthermore, it can also be applied to substrates containing sealing joints.

[0079] In particular, the aqueous coating material of the present invention is suitable as a primer for repairing a substrate, and can be suitably used as a primer when repairing the substrate of, for example, a siding board or the like that has an existing coating film.

[0080] The existing coating film is a coating film that has already been applied to the substrate by on-site painting or factory painting (line painting), and examples thereof include at least one coating film selected from organic coating films, inorganic coating films, and organic-inorganic composite coating films. Examples of the existing coating film include colored coating films (enamel coating films, printed coating films, etc.), clear coating films, and laminated coating films thereof, and are coating films formed by applying and curing various coating materials to the substrate. Such coating materials may be any of room temperature drying, room temperature curing, bake curing, ultraviolet (UV) curing, electron beam curing, etc.

[0081] Examples of binders for such coating materials include organic binders such as acrylic resin, polyurethane resin, epoxy resin, fluororesin, alkyd resin, and polyester resin, inorganic binders such as silicone resin, alkoxysilane, colloidal silica, and silicate, and organic-inorganic composite binders such as acrylic silicone resin.

[0082] The present invention is particularly suitable when the existing coating film is one or more selected from inorganic coating films (coating films containing the above-mentioned inorganic binder), organic-inorganic composite coating films (coating films containing the above-mentioned organic-inorganic composite binder), fluororesin coating films (coating films containing the above-mentioned fluororesin), etc., and can further be suitably applied to clear coating films of these. Such existing coating films may contain photocatalytic titanium oxide, etc.

[0083] Specific coating materials include, for example, weather-resistant topcoat paint for architecture (JIS K5658:2010), weather-resistant paint for steel structures (JIS K5659:2008), glossy synthetic resin emulsion paint (JIS K5660:2008), fire-retardant paint for architecture (JIS K5661:1970), synthetic resin emulsion paint (JIS K5663:2008), road marking paint (JIS K5665:2011), multicolor pattern paint (JIS K5667:2003), synthetic resin emulsion pattern paint (JIS K5668:2010), acrylic resin non-aqueous dispersion paint (JIS K5670:2008), lead- and chromium-free rust-preventive paint (JIS K5674:2008), high solar reflectance paint for roofs (JIS K5675:2011), and floor paint for buildings (JIS K5970:2008), architectural coating waterproofing materials (JIS A6021:2011), architectural finishing coating materials (JIS A6909:2014), etc.

[0084] Examples of the coating film forming method using the aqueous coating material of the present invention as a primer include: A coating method for forming a coating on a substrate is to apply a primer and then a topcoat, and the aqueous coating material of the present invention is used as the primer. This allows the formation of a coating with excellent adhesion to various substrates and topcoats.

[0085] The aqueous coating material of the present invention can be applied by various methods, such as brush coating, roller coating, spray coating, etc. When coating in a factory, a roll coater, flow coater, etc. can also be used in addition to the above methods.

[0086] The amount of the aqueous coating material to be applied is preferably 0.05 to 0.5 kg / m 2 (More preferably 0.07 to 0.3 kg / m 2 ) The number of coats of the aqueous coating material may be determined as appropriate depending on the condition of the substrate, but is preferably 1 to 2 coats. The drying time of the aqueous coating material is preferably 1 hour to 1 week. The drying temperature is preferably -10°C to 50°C, more preferably -5°C to 40°C. The aqueous coating material of the present invention is preferably a room temperature curing type.

[0087] The gel fraction of the formed coating film formed by the above method is preferably 25% or more (preferably 30% or more, more preferably 35% or more). The upper limit is not particularly limited, but practically it is preferably 95% or less (more preferably 90% or less). When the formed coating film satisfies such a range, it is possible to ensure excellent adhesion to the substrate and a wide variety of topcoat materials. The method for calculating the gel fraction is as described above.

[0088] The topcoat material is not particularly limited as long as it is generally used for painting buildings, and examples of the binder include organic binders such as acrylic resin, polyurethane resin, epoxy resin, fluororesin, alkyd resin, polyester resin, etc., or inorganic binders such as silicon resin, alkoxysilane, colloidal silica, silicate, and organic-inorganic composite binders such as acrylic silicon resin. In particular, in the present invention, the adhesion with the topcoat material containing one or more selected from the above organic binders and the above organic-inorganic composite binders can be fully demonstrated. In addition, the form of the topcoat material may be either a water-based topcoat material, a solvent-based (weak solvent-based) topcoat material, etc.

[0089] Specific topcoat materials include, for example, weather-resistant topcoat paints for architecture (JIS K5658:2010), weather-resistant paints for steel structures (JIS K5659:2008), glossy synthetic resin emulsion paints (JIS K5660:2008), fire-retardant paints for architecture (JIS K5661:1970), synthetic resin emulsion paints (JIS K5663:2008), road marking paints (JIS K5665:2011), multicolor pattern paints (JIS K5667:2003), synthetic resin emulsion pattern paints (JIS K5668:2010), acrylic resin non-aqueous dispersion paints (JIS K5670:2008), lead- and chromium-free rust-preventive paints (JIS K5674:2008), high solar reflectance paints for roofs (JIS K5675:2011), and floor paints for buildings (JIS K5970:2008), architectural coating waterproofing materials (JIS A6021:2011), architectural finishing coating materials (JIS A6909:2014), etc.

[0090] The method of applying the topcoat material is not particularly limited and can be applied by known methods, but can be applied by various methods such as brush application, trowel application, spray application, roller application, roll coater, flow coater, etc. In other words, each topcoat material can be applied based on the usual process with the optimal coating specifications for each topcoat material (number of coats, drying temperature, etc.). 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 coating formation method of the present invention is preferable as a room temperature curing type. [Example]

[0091] Examples and comparative examples will be given below to clarify the features of the present invention.

[0092] <Production of main components 1 to 15> The epoxy resin emulsion (A), acrylic resin emulsion (C), organic solvent (D), silane compound (S), catalyst (P), additives, and water were mixed in the mixing ratios shown in Table 1 to form main components 1 to 15.

[0093] <Preparation of Curing Agents 1 and 2> The amino group-containing resin (B1) was used as a curing agent 1. Furthermore, a mixture of the amino group-containing resin (B1) and the amino group-containing silane compound (S3) in a weight ratio of 3:7 was used as a curing agent 2.

[0094] The following raw materials were used: Epoxy resin emulsion (A) (A1) Epoxy resin emulsion [bisphenol A type epoxy resin (solid type) water 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, styrene addition reaction product of meta-xylenediamine, solid content 100% by weight, active hydrogen equivalent y b :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 solvents (D) (D1) Dipropylene glycol-n-butyl ether [boiling point 229°C, solubility in water at 20°C 5g / 100gH2O] (D2) 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate [boiling point 2853°C, solubility in water at 20°C 0.09g / 100gH2O] (D3) Propylene glycol [boiling point 187°C, solubility in water at 20°C ∞] Silane compounds (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: antifoaming agents, thickeners, etc.

[0095] [Table 1]

[0096] (Examples 1 to 26, Comparative Examples 1 to 4) The base resin 1 and curing agent 1 or 2 shown in Table 1 were mixed together at the epoxy equivalent of component (A) in the base resin ([X A ]: solid content equivalent) and the active hydrogen equivalent of component (B) in the curing agent ([Y B ]; solid content equivalent) ratio [X A / (Y B The following evaluations were carried out using an aqueous coating material (clear type aqueous coating material) mixed so that the β-dispersion coefficient (β) of the curing agent was 1.0. The combinations of the base agent and the curing agent are shown in Tables 2 and 3.

[0097] <Water resistance evaluation> The existing coating was prepared by mixing the base agent and hardener to form a water-based coating material, which was applied immediately after mixing to a thickness of 0.15 mm onto a black acrylic plate (150 mm x 200 mm x 3 mm), and then drying under standard conditions (air temperature 23°C, relative humidity 50%) for one day to prepare specimen [I]. Each specimen was immersed in water at 20°C for 48 hours, then removed and dried (23°C, 3 hours). The condition of the coating was visually observed and evaluated for swelling, peeling, whitening, etc. The evaluation criteria were a six-point scale (AA>A>AB>B>C>D), with "A" being almost no abnormality and "D" being abnormality. The results are shown in Tables 2 and 3.

[0098] <Adhesion evaluation 1> (Preparation of test specimen) Test specimen [II] On a siding board with an inorganic clear coating as the existing coating, a water-based coating material (clear type water-based coating material) obtained by mixing the base agent and hardener in the combination shown in Table 3 was applied at an amount of 0.1 kg / m. 2 The mixture was applied immediately after mixing, and dried for 4 hours under standard conditions (temperature 23°C, relative humidity 50%). Then, a water-based topcoat (acrylic silicone resin emulsion paint) was applied at a rate of 0.1 kg / m. 2 The test specimen [I] was prepared by applying the paint as shown in the figure and drying it for one day in a 50°C environment.

[0099] The adhesiveness of the prepared specimen [I] was evaluated using the cross-cut tape method in accordance with JIS K 5600-5-6. The results are shown in Tables 2 and 3. The evaluation criteria are as follows: AA: Defect area less than 5% A: Defect area is 5% or more but less than 10% AB: Defect area is 10% or more but less than 25% B: Defect area is 25% or more but less than 40% C: Defect area is 40% or more but less than 55% D: Defective area is 55% or more

[0100] In Examples 1 to 26, good results were obtained in the water resistance evaluation. Furthermore, in Examples 14 to 26, excellent results were also obtained in the adhesion evaluation 1.

[0101] Next, for Examples 14 to 26, the following test specimens were prepared and adhesion evaluation 2 and adhesion evaluation 3 were carried out. <Adhesion evaluation 2> (Preparation of test specimen) Test specimens [III] to [V] A water-based coating material was applied at a rate of 0.1 kg / m on a siding board that had an inorganic clear coating film formed as an existing coating film. 2The mixture was applied immediately after mixing, and dried for 4 hours under standard conditions (temperature 23°C, relative humidity 50%). Then, a water-based topcoat (acrylic silicone resin emulsion paint) was applied at a rate of 0.1 kg / m. 2 The coating was applied as shown above, and specimens [III], [IV], and [V] were prepared by drying for one day, four days, and seven days under standard conditions, respectively. The prepared specimens [III] to [V] were evaluated for adhesion in the same manner as the specimen [I]. The results are shown in Table 3.

[0102] <Adhesion evaluation 3> (Preparation of test specimen) Test Subject [VI] A water-based coating material was applied at a rate of 0.1 kg / m on a siding board that had an inorganic clear coating film formed as an existing coating film. 2 The mixture was applied immediately after mixing, dried for 7 days in a 23°C environment, and then a water-based topcoat (acrylic silicone resin emulsion paint) was applied at a rate of 0.1 kg / m. 2 The test specimen [VI] was prepared by applying the coating as shown in the figure and drying it for one day under standard conditions. Test Subject [VII] A water-based coating material was applied at a rate of 0.1 kg / m on a siding board that had an inorganic clear coating film formed as an existing coating film. 2 The mixture was applied immediately after mixing, dried at 5°C for 7 days, and then a water-based topcoat (acrylic silicone resin emulsion paint) was applied at a rate of 0.1 kg / m. 2 The test specimen [VII] was prepared by applying the coating as shown in the figure and drying it for one day under standard conditions. The prepared specimens [VI] and [VII] were evaluated for adhesion in the same manner as specimen [I]. The results are shown in Table 3.

[0103] [Table 2]

[0104] [Table 3]

[0105] <Adhesion evaluation 4> (Preparation of test specimen) Test Subject [VIII] On a siding board with an inorganic clear coating film formed as an existing coating film, the aqueous coating materials (clear type aqueous coating materials) of Example 19 [Main agent 6 (gel fraction of component (C5): 0%) and hardener 2] and Example 23 [Main agent 10 (gel fraction of component (C2): 70%) and hardener 2] were applied in an amount of 0.1 kg / m. 2 The mixture was applied immediately after mixing and allowed to dry for 4 hours under standard conditions (temperature 23°C, relative humidity 50%). Next, a weak solvent-based topcoat (acrylic silicone resin paint) was applied at a rate of 0.1 kg / m. 2 After drying and curing for 24 hours in a 23°C environment, the same weak solvent topcoat was applied at an application rate of 0.1 kg / m. 2 The specimens coated with the above were designated as specimens [VIII], and their appearance was visually evaluated, and their adhesion was evaluated in the same manner as for specimen [I]. As a result, in Example 19 (gel fraction of the formed coating: 25%), lifting (shrinkage) was observed and the adhesion was rated "C." On the other hand, in Example 23 (gel fraction of the formed coating: 60%), no abnormalities were observed in the coating and the adhesion was rated "AA."

Claims

1. An aqueous coating material having a base 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; The present invention further comprises 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. An aqueous coating material characterized by:

2. 2. The aqueous coating material according to claim 1, wherein the acrylic resin emulsion (C) is a polymer of a monomer group including an epoxy group-containing monomer.

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