JP5543581B2 - Water-based coating composition and coating film forming method - Google Patents

Description

  The present invention relates to an aqueous coating composition and a coating film forming method.

  In general, a solvent-type paint containing an epoxy resin and a polyamine compound is used as an anticorrosion paint. However, in recent years, from the viewpoint of environmental protection, there is a social demand for switching from solvent-based paints to water-based paints. As such a water-based paint, for example, a water-soluble polyamine resin blended with various pigments and additives as a main agent, and further includes an epoxy resin emulsion and an acrylic silicon resin emulsion containing a glycidyl group and an alkoxysilyl group. An aqueous paint is mentioned (patent document 1).

  However, when a curing reaction between an epoxy resin and a polyamine compound is used, the curing reaction is unlikely to proceed at a low temperature (for example, 5 ° C. or lower), so that a coating film that exhibits practical performance at a low temperature is formed. Is difficult.

JP-A-11-166153

  The present invention has been made to solve the above-described conventional problems, and an object of the present invention is to provide an aqueous coating composition capable of forming a coating film having excellent low-temperature curability and excellent corrosion resistance. There is.

The aqueous coating composition of the present invention comprises an aqueous epoxy polyamine resin (A) having one or more primary amino groups and / or secondary amino groups in the molecule, and one or more (meth) acryloyl in the molecule. An aqueous coating composition comprising a group-containing compound (B) and an alkoxysilane compound (C), the amino group of the aqueous epoxy polyamine resin (A) and the (meth) acryloyl group of the compound (B) Equivalent ratio ((meth) acryloyl group / amino group) is 0.7 to 2.5, and the content of the alkoxysilane compound (C) is 0. 0 in the solid content of the aqueous coating composition. It is 2 mass%-5 mass%.
In a preferred embodiment, the aqueous coating composition is a two-component aqueous coating composition, the main coating liquid contains the aqueous epoxy polyamine resin (A), and the curing agent is the compound (B) and an alkoxysilane compound. (C) is included.
In preferable embodiment, the said water-based epoxy-type polyamine resin (A) is a water dispersion type.
In preferable embodiment, the equivalent of the amino group of the said water-based epoxy-type polyamine resin (A) is 100-3000.
In preferable embodiment, the said water-based epoxy-type polyamine resin (A) is obtained by amine-modifying an epoxy resin, and the epoxy equivalent of this epoxy resin is 180-3800.
In a preferred embodiment, the aqueous coating composition of the present invention is an aqueous epoxy polyamine obtained by amine-modifying an epoxy resin (a1) having an epoxy equivalent of 400 to 1500 as the aqueous epoxy polyamine resin (A). Resin (A1) and the water-based epoxy-type polyamine resin (A2) obtained by amine-modifying the epoxy resin (a2) whose epoxy equivalent is 2000-3200 are included.
In preferable embodiment, mass ratio a1 / a2 of the said epoxy resin (a1) and the said epoxy resin (a2) is 8/2-2/8.
In a preferred embodiment, the aqueous epoxy polyamine resin (A) is obtained by neutralizing the amino group of the epoxy polyamine resin with an acid, and the neutralization rate during the neutralization is 10% to 70%. is there.
In preferable embodiment, the viscosity in 25 degreeC of the said compound (B) is 3000 mPa * s or less.
In a preferred embodiment, the aqueous coating composition of the present invention further contains a pigment, and the pigment volume concentration of the pigment is 20% to 50%.
According to another situation of this invention, the coating-film formation method is provided. In this coating film forming method, the aqueous coating composition is applied to form a coating film.
In a preferred embodiment, the coating film forming method of the present invention further forms a top coat layer by applying a top coat.

  The aqueous coating composition of the present invention comprises an aqueous epoxy polyamine resin (A) having one or more primary amino groups and / or second amino groups in the molecule, and one or more (meth) acryloyl groups in the molecule. By including the compound (B) and the alkoxysilane compound (C) having the above, it is possible to form a coating film that exhibits excellent low-temperature curability and excellent corrosion resistance.

A. Overview of aqueous coating composition The aqueous coating composition of the present invention comprises an aqueous epoxy polyamine resin (A) having one or more primary amino groups and / or second amino groups in the molecule, and one or more in the molecule. The (meth) acryloyl group-containing compound (B) and the alkoxysilane compound (C) are included. The aqueous coating composition of the present invention can form a coating film by mixing the aqueous epoxy polyamine resin (A) and the compound (B) to advance the curing reaction of these compounds. Since the water-based epoxy polyamine resin (A) and the compound (B) can undergo a curing reaction even at a low temperature (for example, 5 ° C.), the water-based coating composition of the present invention is excellent in low-temperature curability. Moreover, the water-based coating composition of this invention can form the coating film which is excellent in adhesiveness with a base material by including the alkoxysilane compound (C). Such excellent adhesion can be obtained even when a coating film is formed at a low temperature.

  The aqueous coating composition of the present invention is preferably a two-component aqueous coating composition comprising a main component coating liquid and a curing agent. Preferably, the main component coating liquid contains the water-based epoxy polyamine resin (A), and the curing agent contains the compound (B) and the alkoxysilane compound (C). By using the aqueous coating composition of the present invention as a two-pack type aqueous coating composition, it is possible to select a combination in which the aqueous epoxy polyamine resin (A) and the compound (B) are highly reactive with each other. Therefore, an aqueous coating composition having excellent low-temperature curability can be obtained.

  The aqueous coating composition of the present invention comprises (1) diluting the compound (B) with an organic solvent before mixing the aqueous epoxy polyamine resin (A) and the compound (B). An emulsifier is mixed with B), or the compound (B) is emulsified or dispersed with a dispersant, an emulsifier or an aqueous resin, or (3) a dispersion of a resin different from the aqueous epoxy polyamine resin (A) is mixed with the compound (B). You may perform the process of disperse | distributing in the body. By performing such a treatment, the aqueous epoxy polyamine resin (A) and the compound (B) can be mixed without using a special mixing apparatus, and an aqueous coating composition having excellent dispersibility can be obtained. As a result, the aqueous epoxy polyamine resin (A) and the compound (B) can be reacted with each other efficiently. Further, if the compound (B) (2) is mixed with an emulsifier, or the compound (B) is emulsified or dispersed with a dispersant, an emulsifier or an aqueous resin, the compound (B) is regarded as a non-dangerous substance. It can be handled.

  Examples of the organic solvent for diluting the compound (B) with an organic solvent include ethylene glycol monobutyether and diethylene glycol monobutyl ether.

  As the emulsifier when the compound (B) is mixed with an emulsifier, or the compound (B) is emulsified or dispersed with a dispersant, an emulsifier or an aqueous resin, for example, a nonionic emulsifier, an anionic emulsifier, or the like is used. Examples of the nonionic emulsifier include polyoxyethylene alkylphenol ether, polyoxyethylene styrenated phenyl ether, polyoxyethylene alkyl ether, polyoxyethylene polyoxypropylene block polymer, sorbitan fatty acid ester and the like. Examples of the anionic emulsifier include dodecylbenzene sulfonate, dialkyl succinate sulfonate, polyoxyethylene alkyl ether sulfate, polyoxyethylene styrenated phenyl ether sulfate, alkyl diphenyl ether disulfonate, and the like. . Examples of the dispersant include polyacrylic acid sodium salt, ammonium salt of half ester of styrene maleic acid copolymer, and the like. As said aqueous resin, the soda salt of polyacrylic acid ester etc. are mentioned, for example.

  Examples of the dispersion when the compound (B) is dispersed in a resin dispersion different from the aqueous epoxy polyamine resin (A) include, for example, an acrylic resin emulsion and dispersion, a urethane resin emulsion and dispersion, and the like. Is mentioned.

  The content of the aqueous epoxy polyamine resin (A) as a solid content is preferably 5% by mass to 95% by mass and more preferably 10% by mass to 90% by mass with respect to the total solid content of the aqueous coating composition. % By mass.

  The content of the compound (B) is preferably 2% by mass to 30% by mass and more preferably 5% by mass to 25% by mass with respect to the total solid content of the aqueous coating composition.

  The equivalent ratio ((meth) acryloyl group / amino group) of the amino group of the aqueous epoxy-based polyamine resin (A) to the (meth) acryloyl group of the compound (B) is 0.7 to 2.5, Preferably it is 0.8-2.0. When the equivalent ratio is less than 0.7, the low temperature curability of the aqueous coating composition may be lowered. When exceeding 2.5, there exists a possibility that the adhesiveness of the coating film obtained may fall.

  Content of the said alkoxysilane compound (C) is 0.2 mass%-5 mass% with respect to the total solid content of an aqueous coating composition, Preferably it is 0.3 mass%-3 mass%, More preferably, it is 0.5 mass%-2 mass%. If the content of the alkoxysilane compound (C) is in such a range, it is possible to obtain an aqueous coating composition that is excellent in adhesion to the substrate and as a result can form a coating film exhibiting excellent anticorrosion properties. it can. Note that even if the content of the alkoxysilane compound (C) is more than 5% by mass, there is no further improvement in adhesion, but rather the curability (particularly low temperature curability) of the coating film may be lowered.

  The aqueous coating composition of the present invention may further contain a pigment. By including the pigment, the viscosity of the aqueous coating composition can be increased, and the film thickness obtained by one coating can be increased. As a result, since the number of coatings can be reduced, it is possible to obtain an aqueous coating composition that is excellent in coating workability and can form a coating film exhibiting sufficient corrosion resistance.

  Specific examples of the pigment include extender pigments such as precipitated barium sulfate, clay, talc, and mica; colored pigments such as titanium dioxide and carbon black; and rust preventive pigments such as zinc phosphate.

  The pigment volume concentration of the pigment in the aqueous coating composition is preferably 20% to 50%, more preferably 25% to 45%, and particularly preferably 30% to 40%. When the pigment volume concentration is less than 20%, the effect of containing the pigment may not be sufficiently obtained. When the pigment volume concentration is more than 50%, the coating film appearance may be deteriorated. The pigment volume concentration can be obtained by calculation from the blending mass of the pigment and the specific gravity of each component in the paint.

  The water-based coating composition of the present invention may contain water, a solvent, an additive and the like. Specific examples of the solvent include glycol solvents such as ethylene glycol, propylene glycol, ethylene glycol monobutyl ether, propylene glycol monobutyl ether, diethylene glycol, dipropylene glycol, diethylene glycol monobutyl ether, dipropylene glycol monobutyl ether, diethylene glycol dibutyl ether; xylene, Aromatic solvents such as Solvesso 100, Solvesso 150 and Solvesso 200; hydrocarbon solvents such as mineral spirits; 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate (trade name “manufactured by Chisso Corporation” CS-12 "), 2,2,4-trimethyl-1,3-pentanediol diisobutyrate (manufactured by Chisso, trade name" CS-16 "), diethyl adipate And ester solvents such as diisobutyl adipate. Specific examples of the additive include a dispersant, a viscosity modifier, a curing catalyst, a surface modifier, an antifoaming agent, a plasticizer, a film-forming aid, an ultraviolet absorber, and an antioxidant. When the aqueous coating composition of the present invention is used as a two-component aqueous coating composition, water, solvent and / or additive are added to the main coating liquid or curing agent before mixing the main coating liquid and the curing agent. Alternatively, it may be added after mixing the main coating liquid and the curing agent. Whether water, a solvent and / or an additive is added to the main coating liquid or the curing agent can be determined depending on the expected function and properties.

B. Aqueous epoxy polyamine resin (A)
The aqueous coating composition of the present invention includes an aqueous epoxy polyamine resin (A) having one or more primary amino groups and / or secondary amino groups in the molecule. In the present specification, “aqueous” is a concept including “water-soluble” and “water-dispersed”.

  Preferably, the aqueous epoxy polyamine resin (A) is a water-dispersed type. If the water-dispersed aqueous epoxy polyamine resin (A) is used, an aqueous coating composition capable of forming a coating film excellent in water resistance can be obtained. Further, if the water-based epoxy polyamine resin (A) is water-dispersed, it can be easily mixed with the compound (B), and the water-based epoxy polyamine resin (A) and the compound (B) are rapidly mixed. It is possible to obtain an aqueous coating composition having a long pot life by suppressing the progress of the reaction and appropriately adjusting the reactivity. More specifically, if the water-based epoxy polyamine resin (A) is a water-dispersed type, the water-based paint composition before coating is difficult to contact the water-based epoxy polyamine resin (A) and the compound (B). The reaction does not proceed easily even at room temperature, and the storage and coating properties are good. On the other hand, after the coating, the dispersion medium (for example, water) volatilizes, the aqueous epoxy polyamine resin (A) and the compound (B) are easily brought into contact with each other, and the curing reaction proceeds even at a low temperature. Can be formed.

  The aqueous epoxy polyamine resin (A) can be obtained, for example, by amine-modifying an epoxy resin. Moreover, when the epoxy-type polyamine resin obtained by amine-modifying an epoxy resin is not aqueous, for example, it is made aqueous by neutralizing the amino group of the epoxy-type polyamine resin with an acid to form an aqueous epoxy-type polyamine resin ( A) can be obtained.

  Any appropriate epoxy resin can be used. Bisphenol A type epoxy resins or bisphenol F type epoxy resins are preferred, and bisphenol A type epoxy resins are particularly preferred.

  The epoxy equivalent of the epoxy resin can be determined according to the desired film properties. Preferably it is 180-3800, More preferably, it is 400-3200, Most preferably, it is 700-3200. If the epoxy equivalent of an epoxy resin is such a range, the coating film which is excellent in water resistance, corrosion resistance, and water-resistant adhesiveness can be obtained. When the epoxy equivalent of the epoxy resin is less than 180, the initial rainfall resistance of the resulting coating film may be lowered. On the other hand, if it exceeds 3,800, the epoxy-based polyamine resin may cause phase separation without being dispersed in water, and the coating composition may not be made water-based, and an aqueous coating composition having sufficient water-resistant adhesion can be obtained. There is a risk of not. In addition, the epoxy equivalent of an epoxy resin can be calculated | required according to JISK7236. Further, in this specification, “initial rain resistance” means water resistance at the initial stage of curing of a coating film, specifically, at a stage where a coating film that is not completely cured but has no stickiness is formed. . When the initial rainfall resistance is inferior, if the coated film is exposed to rain before the coated film is completely cured, the coated film may be cracked or blistered. Water-based paint compositions that can form a coating with high initial rainfall resistance are particularly effective for applications to outdoor coatings that may be exposed to rainfall after application and before the coating is fully cured It is.

  In one embodiment, the epoxy resin is an epoxy resin (a1) having an epoxy equivalent of 400 to 1500. If the aqueous epoxy polyamine resin (A1) obtained by amine-modifying such an epoxy resin (a1) is used, an aqueous coating composition capable of forming a coating film excellent in water-resistant adhesion can be obtained. The epoxy equivalent of the epoxy resin (a1) is more preferably 600 to 1400, and particularly preferably 800 to 1300.

  In another embodiment, the epoxy resin is an epoxy resin (a2) having an epoxy equivalent of 2000 to 3200. By using an aqueous epoxy polyamine resin (A2) obtained by amine modification of such an epoxy resin (a2), an aqueous coating composition capable of forming a coating film excellent in initial rainfall resistance can be obtained. The epoxy equivalent of the epoxy resin (a2) is more preferably 2200 to 3000.

  The epoxy resin may be used in combination of two or more epoxy resins.

  As the above-mentioned epoxy resin, there can be used those obtained by extending the chain using the reaction between an active hydrogen-containing compound capable of reacting with an epoxy group and the epoxy group to increase the molecular weight or modifying it. Examples of the active hydrogen-containing compound include bifunctional compounds such as dimer acid, diamine, and polyether polyol.

  As the epoxy resin, a resin to which a fatty acid is added before amine modification can be used. By this addition, it is possible to reduce the reactivity by introducing a soft component into the resin or reducing the number of epoxy groups to reduce the number of amine-modified sites.

  The epoxy polyamine resin can be obtained by modifying the epoxy resin by any suitable modification method. Examples of the modification method include a method of adding a first amino group-containing polyamine to an epoxy resin and a method of adding a ketiminated amino group-containing compound to an epoxy resin. The epoxy polyamine resin thus obtained has one or more primary amino groups and / or secondary amino groups and secondary hydroxyl groups in the molecule. The epoxy-based polyamine resin has a functional group such as an epoxy group, an acid anhydride group, an acid halogen group, or an isocyanate group in a part of the first amino group, the second amino group, and / or the hydroxyl group of the epoxy-based polyamine resin. It may be a resin obtained by reacting a compound. As a part of the aqueous epoxy polyamine resin (A) to be used, the physical properties of the resulting coating film are adjusted by including an aqueous product of an epoxy polyamine resin reacted with a compound having such a functional group. Can do.

  The method of adding the first amino group-containing polyamine to the epoxy resin means that the first amino group of the first amino group-containing polyamine is reacted with the epoxy group of the epoxy resin to form a second amino group, As a result, the epoxy polyamine resin having the second amino group is produced.

  Examples of the first amino group-containing polyamine include diethylenetriamine, dipropylenetriamine, dibutylenetriamine, and triethylenetetramine. These may be used alone or in combination.

  The method of adding the ketiminized amino group-containing compound to the epoxy resin means that the ketimine group is hydrolyzed after reacting the ketiminized amino group-containing compound and the epoxy resin, thereby the first amino group. As a result, the epoxy-based polyamine resin having the first amino group is produced. In addition, when reacting the ketiminated amino group-containing compound and the epoxy resin, secondary amines such as diethanolamine, methylethanolamine, and diethylamine may coexist.

  The ketiminated amino group-containing compound can be obtained by reacting a first amino group-containing compound with a ketone. Examples of the first amino group-containing compound include first amino group-containing polyamines such as diethylenetriamine, dipropylenetriamine, dibutylenetriamine, and triethylenetetramine; aminoethylethanolamine, methylaminopropylamine, ethylaminoethylamine, and the like. It is done. These may be used alone or in combination. Examples of the ketone include methyl ethyl ketone, acetone, and methyl isobutyl ketone.

  The epoxy-based polyamine resin may be further modified by reacting with a compound having a functional group that reacts with an amino group, depending on the desired physical properties of the coating film. Examples of the functional group that reacts with an amino group include an epoxy group, a (meth) acryloyl group, an isocyanate group, and an acid anhydride group.

  Any appropriate amount of amino groups can be adopted as the amount of amino groups of the epoxy-based polyamine resin depending on the properties of the desired aqueous coating composition or the physical properties of the coating film. The amount of the amino group is preferably 100 to 3000, more preferably 500 to 2000, and particularly preferably 800 to 2000 as the equivalent of the amino group. When the amino group equivalent is in such a range, the epoxy-based polyamine resin is water-based, and the water-based epoxy-based polyamine resin (A) can be obtained. If the said water-based epoxy-type polyamine resin (A) is used, the coating film which is excellent in low-temperature curability can be obtained. If the equivalent of the amino group of the epoxy-based polyamine resin is less than 100, the resulting coating film may have low water resistance. On the other hand, when it exceeds 3000, the epoxy-based polyamine resin does not disperse in water but causes phase separation, and the coating composition may not be water-based. In this specification, “equivalent of amino group” means that the epoxy-based polyamine resin has a first amino group (including the case where the epoxy-based polyamine resin has a first amino group and a second amino group), When the epoxy-based polyamine resin does not have the first amino group, the molecular weight of the resin solid per one second amino group is indicated by the molecular weight of the resin solid per one amino group. The amino group equivalent of the epoxy-based polyamine resin can be determined from the amount of the raw material blended.

  The aqueous epoxy polyamine resin (A) can also be obtained, for example, by making the amino group of the epoxy polyamine resin (that is, amine-modified epoxy resin) neutralized with an acid to make it aqueous. The type of acid and the neutralization rate (neutralization rate with respect to the amino group of the epoxy-based polyamine resin before making it aqueous) depend on the desired state of the aqueous epoxy-based polyamine resin (A) (water-soluble to water-dispersed type). Any suitable acid type and neutralization rate may be employed. Examples of the acid include acetic acid, formic acid, lactic acid, and phosphoric acid. The neutralization rate (neutralization rate with respect to amino groups of the epoxy-based polyamine resin before making it aqueous) is preferably 10% to 100%, more preferably 10% to 70%, and particularly preferably 15% to 50%. %. If the neutralization rate is less than 10%, the resin does not disperse in water and phase separation may occur, and the coating composition may not be water-based. Moreover, if the neutralization rate is adjusted to 70% or less, a water-dispersed aqueous epoxy polyamine resin (A) can be obtained.

  Arbitrary appropriate molecular weight can be employ | adopted for the molecular weight (number average) of the said water-based epoxy-type polyamine resin (A) according to the characteristic or coating-film physical property of a desired water-based coating composition. Preferably, it is 500-20000 in terms of standard polystyrene using gel permeation chromatography (GPC), and more preferably 1000-10000. If the molecular weight of the aqueous epoxy polyamine resin (A) is in such a range, the aqueous epoxy polyamine resin (A) and the above compound (B) can be easily mixed, so that they can be reacted efficiently. Can do. Moreover, if the molecular weight of water-based epoxy-type polyamine resin (A) is such a range, the coating film which is excellent in corrosion resistance, water resistance, and adhesiveness can be obtained.

  The aqueous coating composition of the present invention may contain two or more of the above-mentioned aqueous epoxy polyamine resins (A).

  The aqueous coating composition of the present invention is preferably an aqueous epoxy polyamine resin (A) obtained by amine modification of the epoxy resin (a1) having an epoxy equivalent of 400 to 1500 as the aqueous epoxy polyamine resin (A). A1) and the aqueous epoxy polyamine resin (A2) obtained by amine-modifying the epoxy resin (a2) having an epoxy equivalent of 2000 to 3200. The mass ratio a1 / a2 between the epoxy resin (a1) having an epoxy equivalent of 400 to 1500 and the epoxy resin (a2) having an epoxy equivalent of 2000 to 3200 is preferably 8/2 to 2/8, More preferably, it is 7/3 to 3/7. If it is such a range, the water-based coating composition which can form the coating film excellent in initial rainfall resistance and water-resistant adhesiveness can be obtained.

  Depending on the molecular weight of the water-based epoxy polyamine resin (A) and the amount of amino groups, the characteristics of the water-based coating composition or the physical properties of the coating film can be controlled.

C. Compound (B)
The compound (B) used in the aqueous coating composition of the present invention has one or more (meth) acryloyl groups in the molecule.

  The molecular weight of the compound (B) is preferably 150 or more and 2000 or less, more preferably 200 or more and 1700 or less, and particularly preferably 250 or more and 1300 or less. If the molecular weight of the compound (B) is in such a range, the aqueous epoxy polyamine resin (A) and the compound (B) can be easily mixed without using a special mixing device, and have excellent dispersibility. Water-based coating composition can be obtained. As a result, the aqueous epoxy polyamine resin (A) and the compound (B) can be efficiently reacted with each other, and an aqueous coating composition having excellent curability can be obtained. The molecular weight of the compound (B) can be calculated from the chemical formula.

  The number of (meth) acryloyl groups possessed by the compound (B) is 1 or more, preferably 2-4. The number of (meth) acryloyl groups possessed by the compound (B) can be determined according to the desired physical properties of the coating film.

  The viscosity at 25 ° C. of the compound (B) is preferably 3000 mPa · s or less, more preferably 50 mPa · s to 3000 mPa · s, particularly preferably 50 mPa · s to 2200 mPa · s, and most preferably 50 mPa · s to 1100 mPa · s. If the viscosity of the compound (B) is in such a range, the aqueous epoxy polyamine resin (A) and the compound (B) can be easily mixed without using a special mixing apparatus, and the dispersibility is excellent. An aqueous coating composition can be obtained. As a result, the aqueous epoxy polyamine resin (A) and the compound (B) can be efficiently reacted with each other, and an aqueous coating composition having excellent curability can be obtained.

  Examples of the compound (B) include ethylene glycol diacrylate, ethylene glycol dimethacrylate, triethylene glycol diacrylate, triethylene glycol dimethacrylate, tetraethylene glycol diacrylate, tetraethylene glycol dimethacrylate, 1, 3 -Butylene glycol diacrylate, 1,3-butylene glycol dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, 1,4-butanediol diacrylate, 1,4-butanediol dimethacrylate, neopentyl Glycol diacrylate, neopentyl glycol dimethacrylate, 1,6-hexanediol diacrylate, 1,6-hexanediol Methacrylate, pentaerythritol diacrylate, pentaerythritol dimethacrylate, pentaerythritol triacrylate, pentaerythritol trimethacrylate, pentaerythritol tetraacrylate, pentaerythritol tetramethacrylate, glycerol diacrylate, glycerol dimethacrylate, glycerol acoxydimethacrylate Acrylate, 1,1,1-trishydroxymethylethane diacrylate, 1,1,1-trishydroxymethylethane dimethacrylate, 1,1,1-trishydroxymethylethane triacrylate, 1,1,1-trishydroxy Methylethane trimethacrylate, 1,1,1-trishydroxymethylpropane diacrylate, 1,1,1 Polymeric unsaturated monocarboxylic acid ester compounds of polyhydric alcohols such as trishydroxymethylpropane dimethacrylate; containing epoxy groups such as glycidyl acrylate and the reaction product of glycidyl methacrylate with acrylic acid, methacrylic acid, crotonic acid and maleic acid Examples include adducts of an ethylenically unsaturated monomer and a carboxyl group-containing ethylenically unsaturated group monomer; and polymerizable unsaturated monocarboxylic amide compounds of polyvalent amines such as ethylenediamine diacrylate. These compounds may be used alone or in combination.

  As described above, it is preferable that the compound (B) can be easily mixed with the aqueous epoxy polyamine resin (A) (both can react). More preferably, the water-based epoxy polyamine resin (A) and the compound (B) are used in a non-uniform state within a range where they can be easily mixed (both can react). Particularly preferably, the compound (B) and the aqueous epoxy polyamine resin (A) are used in mutually different phase states. If it is such a state, the progress of the rapid reaction of water-based epoxy-type polyamine resin (A) and a compound (B) can be suppressed, and reactivity can be adjusted moderately. More specifically, if the water-based epoxy polyamine resin (A) and the compound (B) are in a non-uniform state, the water-based paint composition before coating is difficult to come in contact with both of these components. The reaction does not proceed easily, and the storage and coating properties are good. On the other hand, after the coating, the dispersion medium (for example, water) volatilizes, the aqueous epoxy polyamine resin (A) and the compound (B) are easily brought into contact with each other, and the curing reaction proceeds even at a low temperature. Can be formed. For example, when the compound (B) is a water-soluble compound and the aqueous epoxy polyamine resin (A) is a water-dispersed resin, the compound (B) has a self-emulsifying property or is water-dispersed with a dispersant. And the case where the compound (B) is emulsified or dispersed by the aqueous epoxy polyamine resin (A). It should be noted that whether the compound (B) is “water-insoluble”, “water-soluble” or “self-emulsifying” is determined by adding 5 g of compound (B) to 100 g of water at room temperature. The state after stirring (for example, 3 minutes) and leaving still (for example, after 5 minutes) can be visually observed. After settling, it can be judged as “water-insoluble” if precipitation occurs, “water-soluble” if there is no precipitate and clear, and “self-emulsifying” if there is no precipitation and turbidity. In addition, the same operation is performed in the presence of a dispersant, and if there is no precipitation and turbidity, it can be determined that “the dispersion is in water”.

  For example, when the compound (B) is modified with polyethylene oxide, the number of moles of ethylene oxide added can be increased so that the hydrophilicity can be increased to obtain a water-soluble or self-emulsifying compound.

  Examples of the water-soluble compound (B) include ethoxylated bisphenol A diacrylate (EO 30 mol), ethoxylated trimethylolpropane triacrylate (EO 20 mol), ethoxylated trimethylolpropane triacrylate (EO 30 mol), and ethoxylated pentaerythritol tetra. Examples include acrylate (EO 35 mol), ethoxylated glycerin triacrylate (EO 20 mol), and ethoxylated bisphenol A dimethacrylate (EO 30 mol). These may be used alone or in combination. In the present specification, for example, “EO 30 mol” represents that 30 ethylene oxides are contained in the molecule.

  Examples of the compound (B) having the self-emulsifying property or capable of being dispersed in water with a dispersant include polyethylene glycol # 400 diacrylate (EO 9 mol), polyethylene glycol # 600 diacrylate (EO 14 mol), polyethylene glycol # 1000. Examples include diacrylate (EO 23 mol), ethoxylated bisphenol A diacrylate (EO 10 mol), ethoxylated bisphenol A diacrylate (EO 20 mol), ethoxylated glycerin triacrylate (EO 9 mol), polyethylene glycol # 1000 dimethacrylate (EO 23 mol), and the like. These may be used alone or in combination.

  Examples of the compound (B) that can be emulsified or dispersed by the aqueous epoxy polyamine resin (A) include polyethylene glycol # 200 glycol diacrylate (EO 4 mol), ethoxylated bisphenol A diacrylate (EO 3 mol), and ethoxylated bisphenol A diester. Acrylate (EO 4 mol), propoxylated bisphenol A diacrylate (PO 3 mol), 1,10-decanediol diacrylate, tricyclodecane dimethanol diacrylate, ethoxylated 2-methyl-1,3-propanediol diacrylate (EO 2 mol), Neopentyl glycol diacrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, dipropylene glycol diacrylate (PO2m l), tripropylene glycol diacrylate (PO3 mol), polypropylene glycol # 400 diacrylate (PO7 mol), polypropylene glycol # 700 diacrylate (PO12 mol), ethoxylated trimethylolpropane triacrylate (EO3 mol), ethoxylated trimethylolpropane triacrylate (EO 9 mol), trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate (PO3 mol), pentaerythritol triacrylate, ethoxylated pentaerythritol tetraacrylate (EO4 mol), ditrimethylolpropane tetraacrylate, propoxylated pentaerythritol tetraacrylate (PO4 mol) ), Propoxylated bisph Enol A diacrylate (PO 4 mol), ethylene glycol dimethacrylate (EO 1 mol), diethylene glycol dimethacrylate (EO 2 mol), triethylene glycol dimethacrylate (EO 3 mol), tetraethylene glycol dimethacrylate (EO 4 mol), polyethylene glycol # 400 dimethacrylate (EO 9 mol) , Polyethylene glycol # 600 dimethacrylate (EO 14 mol), 1,3-butanediol dimethacrylate, 1,4-butanediol dimethacrylate, 1,6-hexanediol dimethacrylate, 1,9-nonanediol dimethacrylate, ethoxylated bisphenol A dimethacrylate (EO 2.6 mol), ethoxylated bisphenol A dimethacrylate (EO 4 mol), ethoxylated bisphenol A dimethacrylate (EO 6 mol), ethoxylated bisphenol A dimethacrylate (EO 10 mol), ethoxylated bisphenol A dimethacrylate (EO 17 mol), neopentyl glycol dimethacrylate, ethoxylated polypropylene glycol # 700 dimethacrylate (PO 12 mol, EO 6 mol), glycerin dimethacrylate, tripropylene glycol dimethacrylate (PO 3 mol), polypropylene glycol # 400 dimethacrylate (PO 7 mol), trimethylolpropane trimethacrylate, ethoxylated trimethylolpropane trimethacrylate (EO 9 mol), and the like. These may be used alone or in combination.

  The compound (B) can be used as a mixture of a plurality of types of compounds (B). Thus, the physical property control of a water-based coating composition and the coating film obtained can be performed by combining and using the compound (B) from which a characteristic differs. For example, the curability can be controlled by mixing the compound (B) having two (meth) acryloyl groups and the compound (B) having three (meth) acryloyl groups. If a mixture of the water-soluble compound (B) and the water-insoluble compound (B) is used, the water-insoluble compound (B) is easily introduced into the reaction system by the water-soluble compound (B). be able to. Moreover, the coating material obtained is excellent in low-temperature curability. Examples of the water-insoluble compound (B) include compounds that are not completely water-soluble, such as propoxylated bisphenol A diacrylate (PO4 mol). The mixing ratio (water-soluble / water-insoluble) of the water-soluble compound (B) and the water-insoluble compound (B) is preferably 1/9 to 9/1, more preferably 2/8 to 8 / 2.

D. Alkoxysilane compound (C)
The aqueous coating composition of the present invention contains an alkoxysilane compound (C). If the alkoxysilane compound (C) is included, a coating film having excellent adhesion to the substrate can be obtained. The coating film formed by the aqueous coating composition of the present invention is excellent in adhesion to a substrate even when formed at a low temperature. Thus, the coating film formed with the aqueous coating composition of the present invention having excellent adhesion to the substrate exhibits excellent corrosion resistance.

  The alkoxysilane compound (C) has a functional group showing reactivity or affinity for organic substances and a functional group showing reactivity or affinity for inorganic substances. Therefore, the aqueous coating composition of the present invention can improve the adhesion between the formed coating film (organic substance) and the substrate (inorganic substance) by including the alkoxysilane compound (C). Examples of the functional group showing reactivity or affinity for organic substances include a vinyl group, an epoxy group, a methacryl group, an amino group, a mercapto group, and the like. On the other hand, the functional group showing reactivity or affinity for inorganic substances is preferably a hydrolyzable functional group, and examples thereof include a methoxysilane group, an ethoxysilane group, and a propoxysilane group.

  The alkoxysilane compound (C) may be partially hydrolyzed and / or hydrolyzed and dehydrated, and specific examples thereof include γ-glycidoxypropyltrimethoxysilane and γ-glycidoxypropyltriethoxy. Γ-glycidoxyalkyltrialkoxysilane such as silane and γ-glycidoxypropoxytrimethoxysilane; γ-aminopropyltrialkoxysilane such as γ-aminopropyltriethoxysilane and γ-aminopropyltripropoxysilane; N- N-phenyl-γ-aminoalkyltrialkoxysilane such as phenyl-γ-aminopropyltrimethoxysilane, N-phenyl-γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltripropoxysilane, etc. . Among them, γ-glycidoxyalkyltrialkoxysilane, γ-aminopropyltrialkoxysilane, N-phenyl-γ-aminoalkyltrialkoxysilane, and more preferably γ-glycidoxyalkyltrialkoxysilane, γ-aminopropyltrialkoxysilane, particularly preferably γ-glycidoxyalkyltrialkoxysilane. These may be used alone or in combination.

E. Method for Forming Coating Film The aqueous coating composition of the present invention can be applied to inner and outer plate portions of ships and underwater structures in seawater or fresh water. Concretely, deck and hatch combing, upper part, outer part, engine room, living area, inside and outside parts of a ship such as car hold; seawater or freshwater underwater structures such as piping materials to be coated ( Substrate). Examples of the material of the base material include metal materials such as iron-based, zinc-based, and aluminum-based materials.

  Any appropriate method can be adopted as a coating method of the aqueous coating composition of the present invention. Examples of the coating method include airless coating, air spray, brush coating, trowel coating, and roller coating. Of these, airless coating is preferred. If coating is performed by airless coating, a thick coating can be obtained. Moreover, you may coat several times (for example, 2-3 times), and may form a coating film. If it is applied several times, a thick coating can be formed with good appearance.

  The thickness of the coating film when applying the aqueous coating composition of the present invention is a dry coating film, preferably 50 μm to 250 μm, and more preferably 50 μm to 200 μm. When the thickness of the dried coating film is larger than 250 μm, there is a possibility that problems such as sagging occur when the coating film is formed.

  Any appropriate drying method may be adopted as a method for drying the aqueous coating composition of the present invention. Natural drying or heat drying is preferred. In the case of natural drying, the drying time is preferably 24 hours or longer, more preferably 1 week or longer.

  After forming a coating film with the aqueous coating composition of the present invention, a top coating layer may be formed on the coating film by further applying a top coating composition. According to the present invention, such a multilayer coating film forming method can be provided. If an overcoat layer is formed, a coating film having improved anticorrosion properties and appearance can be obtained.

  Any appropriate paint can be adopted as the top coat. Examples of the top coat include epoxy / amine-based paints, two-component urethane curable paints, one-component urethane curable paints, and paints containing a carbodiimide curing agent. The top coat may be solvent-based or water-based. Preferably, it is aqueous. If the top coat is water-based, the environmental load can be reduced during the formation of the coating film.

  The thickness of the top coat layer can be set to any appropriate thickness depending on the type of paint and the purpose of painting. Typically, the film thickness of the dried coating film is 10 μm to 300 μm.

  An intermediate coating layer may be formed between the coating film formed from the aqueous coating composition and the top coating layer. The intermediate coating layer can be formed by applying an intermediate coating on the coating film formed from the aqueous coating composition. If an intermediate coating layer is formed, a coating film with further improved anticorrosion properties can be obtained.

  Any appropriate coating material can be adopted as the intermediate coating material. Examples of the intermediate coating include epoxy / amine-based paints, two-component urethane curable paints, and one-component urethane curable paints. The intermediate coating material may be solvent-based or water-based. Preferably, it is aqueous. If the intermediate coating is water-based, the environmental load can be reduced when forming the coating film.

  The thickness of the intermediate coating layer can be set to any appropriate thickness depending on the type of coating and the purpose of coating. Typically, the film thickness of the dried coating film is 10 μm to 50 μm.

  Before forming a coating film with the aqueous coating composition, an undercoat layer may be formed by coating an undercoat paint on a substrate. If an undercoat layer is formed, a coating film with improved anticorrosion properties can be obtained.

  Any appropriate paint can be adopted as the undercoat paint. Examples of the undercoat paint include organic or inorganic zinc rich paint. The undercoat paint may be solvent-based or water-based. Preferably, it is aqueous. If the undercoat paint is water-based, the environmental load can be reduced during the formation of the coating film.

  The thickness of the undercoat layer can be set to any appropriate thickness depending on the type of paint and the purpose of painting. Typically, the film thickness of the dried coating film is 20 μm to 300 μm.

  The top coat, intermediate coat and undercoat paint may contain pigments, additives and the like. Examples of the pigment and additive include the pigment and additive described in the above section A. The number, type, and amount of pigments and additives to be added can be appropriately selected depending on the purpose.

  Any appropriate method can be adopted as the coating method and drying method for the top coating material, intermediate coating material, and undercoating coating material, depending on the type of coating material used. Examples of the coating method and the drying method for the top coating material, intermediate coating material, and undercoating coating material include the same methods as the coating method and the drying method for the aqueous coating composition described above.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these Examples. Unless otherwise specified, parts and% in the examples are based on mass.

[Production Example 1] Preparation of water-based epoxy-based polyamine resin (A) I Raw material having an epoxy equivalent of 188 g / equivalent synthesized from bisphenol A and epichlorohydrin in a reaction vessel equipped with a stirrer, a cooler, a nitrogen introduction tube and a thermometer 702 parts of resin, 269 parts of bisphenol A, 108 parts of dimer acid and 190 parts of methyl isobutyl ketone (hereinafter referred to as “MIBK”) are charged and reacted at 117 ° C. until 1 epoxy equivalent of 1079 g / equivalent in the presence of 1 part of benzyldimethylamine. An epoxy resin was obtained. Thereafter, 255 parts of a ketimine compound of aminoethylethanolamine (73 mass% MIBK solution) was added and reacted at 117 ° C. for 1 hour. Then, it diluted with MIBK until it became non-volatile content 75%, and the epoxy-type polyamine resin of 1184 equivalent of an amino group was obtained.
Acetic acid was added thereto to achieve a neutralization rate of 35.0% (neutralization rate relative to the amino group of the resin), and diluted by adding ion-exchanged water. Thereafter, the mixture of MIBK and water was removed under reduced pressure until the solid content became 40% by mass, and a milky white aqueous (water-dispersed) epoxy-based polyamine resin (A) I (specific gravity (solid content) 1.2 g / cm ³ ) was prepared.

[Production Example 2] Production of aqueous epoxy-based polyamine resin (A) II A raw material having an epoxy equivalent of 188 g / equivalent synthesized from bisphenol A and epichlorohydrin in a reaction vessel equipped with a stirrer, a cooler, a nitrogen introduction tube and a thermometer. An epoxy resin was obtained by charging 742 parts of resin, 336 parts of bisphenol A and 190 parts of MIBK and reacting at 117 ° C. in the presence of 1 part of benzyldimethylamine until an epoxy equivalent of 1079 g / equivalent. Thereafter, 350 parts of a diethylenetriamine ketimine compound (73% by mass MIBK solution) was added and reacted at 117 ° C. for 1 hour. Thereafter, 27 parts of ion-exchanged water and 188 parts of neodecanoic acid glycidyl ester (manufactured by Hexion Specialty Chemicals, trade name “Cardura E10-P”) were charged and reacted at 100 ° C. for 2 hours. Then, it diluted with MIBK until it became non-volatile content 75%, and obtained the epoxy-type polyamine resin of 1093 equivalent of an amino group.
Acetic acid was added thereto to achieve a neutralization rate of 35.0% (neutralization rate with respect to the amino group of the resin), and ion-exchanged water was added for dilution. Thereafter, the mixture of MIBK and water was removed under reduced pressure until the solid content became 40% by mass, and a milky white aqueous (water-dispersed) epoxy polyamine resin (A) II (specific gravity (solid content) 1.2 g / cm ³ ) was prepared.

[Production Example 3] Production of aqueous epoxy-based polyamine resin (A) III A raw material having an epoxy equivalent of 188 g / equivalent synthesized from bisphenol A and epichlorohydrin in a reaction vessel equipped with a stirrer, a cooler, a nitrogen introduction tube and a thermometer. An epoxy resin was obtained by charging 525 parts of a resin, 205 parts of bisphenol A, and 110 parts of MIBK and reacting at 117 ° C. until an epoxy equivalent of 730 g / equivalent in the presence of 1 part of benzyldimethylamine. Thereafter, 350 parts of a diethylenetriamine ketimine compound (73% by mass MIBK solution) was added and reacted at 117 ° C. for 1 hour. Thereafter, 27 parts of ion-exchanged water and 188 parts of neodecanoic acid glycidyl ester (manufactured by Hexion Specialty Chemicals, trade name “Cardura E10-P”) were charged and reacted at 100 ° C. for 2 hours. Then, it diluted with MIBK until it became non-volatile content 75%, and the epoxy-type polyamine resin of the equivalent 810 of an amino group was obtained.
Acetic acid was added thereto to achieve a neutralization rate of 20.0% (neutralization rate with respect to the amino group of the resin), and ion-exchanged water was added for dilution. Thereafter, the mixture of MIBK and water was removed under reduced pressure until the solid content reached 40% by mass, and a milky white aqueous (water-dispersed) epoxy-based polyamine resin (A) III (specific gravity (solid content) 1.2 g / cm ³ ) was prepared.

[Production Example 4] Production of aqueous epoxy-based polyamine resin (A) IV A raw material having an epoxy equivalent of 188 g / equivalent synthesized from bisphenol A and epichlorohydrin in a reaction vessel equipped with a stirrer, a cooler, a nitrogen introduction tube and a thermometer. 1940 parts of resin, 1060 parts of bisphenol A and 550 parts of MIBK were charged and reacted at 117 ° C. until the epoxy equivalent was 3000 g / equivalent in the presence of 8 parts of benzyldimethylamine to obtain an epoxy resin. Thereafter, 350 parts of a diethylenetriamine ketimine compound (73% by mass MIBK solution) was added and reacted at 117 ° C. for 1 hour. Thereafter, 1060 parts of dipropylene glycol monobutyl ether (hereinafter referred to as “DPnB”) was charged and reacted at 100 ° C. for 2 hours. Then, it diluted with MIBK until it became non-volatile content 75%, and the epoxy-type polyamine resin of 1550 equivalent of an amino group was obtained.
Acetic acid was added thereto to achieve a neutralization rate of 40.0% (neutralization rate with respect to the amino group of the resin), and ion-exchanged water was added for dilution. Thereafter, the mixture of MIBK and water was removed under reduced pressure until the solid content became 40% by mass, and a milky white aqueous (water-dispersed) epoxy polyamine resin (A) IV (specific gravity (solid content) 1.2 g / cm ³ ) was prepared.

[Production Examples 5 to 7] Production of water-based epoxy polyamine resins (A) V to VII A water-based epoxy polyamine resin was prepared in the same manner as in Production Example 2 except that the neutralization rate was changed to the neutralization rate shown in Table 1 below. (A) V to VII were adjusted. The specific gravity (solid content) of the aqueous epoxy polyamine resins (A) V to VII was 1.2 g / cm ³ .

[Production Example 8] Production of aqueous epoxy-based polyamine resin (A) VIII A raw material having an epoxy equivalent of 188 g / equivalent synthesized from bisphenol A and epichlorohydrin in a reaction vessel equipped with a stirrer, a cooler, a nitrogen introduction tube and a thermometer. 1440 parts of resin, 760 parts of bisphenol A and 388 parts of MIBK were charged and reacted at 117 ° C. in the presence of 3 parts of benzyldimethylamine until an epoxy equivalent of 2200 g / equivalent was obtained. Thereafter, 350 parts of a diethylenetriamine ketimine compound (73% by mass MIBK solution) was added and reacted at 117 ° C. for 1 hour. Next, after further reacting at 100 ° C. for 2 hours, it was diluted with MIBK until the non-volatile content became 75% to obtain an epoxy polyamine resin having an amino group equivalent of 1150.
Acetic acid was added thereto to achieve a neutralization rate of 40.0% (neutralization rate with respect to the amino group of the resin), and ion-exchanged water was added for dilution. Thereafter, the mixture of MIBK and water was removed under reduced pressure until the solid content was 40% by mass, and a milky white aqueous (water-dispersed) epoxy-based polyamine resin (A) VIII (specific gravity (solid content) 1.2 g / cm ³ ) was prepared.

[Production Example 9] Production of epoxy-based polyamine resin An epoxy-based polyamine resin was prepared in the same manner as in Production Example 2 except that the neutralization rate was 5%. The epoxy polyamine resin was phase-separated in water without being made aqueous.

[Production Example 10] Production of epoxy-based polyamine resin 2560 parts of an epoxy equivalent of 188 g / equivalent epoxy resin synthesized from bisphenol A and epichlorohydrin in a reaction vessel equipped with a stirrer, a cooler, a nitrogen introduction tube and a thermometer, bisphenol 1439 parts of A and 706 parts of MIBK were charged and reacted at 117 ° C. in the presence of 5 parts of benzyldimethylamine until an epoxy equivalent of 4000 g / equivalent was obtained to obtain an epoxy resin. Thereafter, 350 parts of a diethylenetriamine ketimine compound (73% by mass MIBK solution) was added and reacted at 117 ° C. for 1 hour. Next, after further reacting at 100 ° C. for 2 hours, it was diluted with MIBK until the non-volatile content became 75% to obtain an epoxy polyamine resin having an amino group equivalent of 2050.
Acetic acid was added thereto to achieve a neutralization rate of 40.0% (neutralization rate with respect to the amino group of the resin), and ion-exchanged water was added for dilution. Thereafter, the mixture of MIBK and water was removed under reduced pressure until the solid content became 40% by mass, to prepare an epoxy polyamine resin. The epoxy polyamine resin was phase-separated in water without being made aqueous.

[Example 1]
(Manufacture of main component paint liquid)
To 110 parts of water, 89.5 parts of talc (made by Fuji Talc Kogyo, trade name “Talc SP42”, specific gravity: 2.7 g / cm ³ ), calcium carbonate (made by Maruo Calcium Co., trade name “N heavy coal”, Specific gravity: 2.7 g / cm ³ ) 89.5 parts, titanium oxide (manufactured by DuPont, trade name “TI-PUR R706”, specific gravity: 4.3 g / cm ³ ), 172 parts, rust preventive pigment (manufactured by Toho Pigment) , 25 parts of a trade name “EXPERT NP1055C”, specific gravity 2.3 g / cm ^{3, 4} parts of an antifoaming agent (manufactured by Sampnoco, trade name “SN deformer 154”, specific gravity: 1.0 g / cm ³ ) and a pigment dispersant A pigment dispersion paste was produced by adding 32 parts (manufactured by Big Chemie, trade name “BYK-190”, specific gravity: 1.0 g / cm ³ ) and stirring with a disper for 30 minutes. To 500 parts of this pigment paste, 400 parts of the aqueous epoxy polyamine resin (A) I obtained in Production Example 1, 24 parts of DPnB, and 1 part of an associative thickener (manufactured by Adeka, trade name “Adecanol UH-420”). In addition, mixing was performed to obtain a base coating material liquid I.
(Manufacture of curing agent)
40 parts of water, 10 parts of DPnB and 50 parts of polyethylene glycol # 400 dimethacrylate (EO 9 mol) (viscosity (25 ° C.): 58 mPa · s, molecular weight: 508, number of functional groups: 2, acryloyl group equivalent: 254) as compound (B) The mixture was mixed and stirred with a homogenizer for 10 minutes to obtain a curing agent I. The specific gravity of the solid content in the curing agent I was 1.2 g / cm ³ .
(Manufacture of water-based paint composition)
An epoxy silane coupling agent (3-glycidoxypropyltrimethoxysilane; manufactured by Shin-Etsu Chemical Co., Ltd., trade name “KBM-403”) was added as an alkoxysilane compound (C) to 40 parts of the curing agent I. Then, the said hardening | curing agent and the said main ingredient coating liquid I500 parts were mixed so that it might become uniform, and the aqueous coating composition 1 was obtained.

[Examples 2 to 22]
An aqueous coating composition was obtained in the same manner as in Example 1 except that the types and amounts of the main coating liquid I, the curing agent I and the alkoxysilane compound (C) were as shown in Table 2 or Table 3.
The main coating liquids II to VIII were obtained in the same manner as in Example 1 except that the aqueous epoxy polyamine resin (A) shown in Table 4 was used instead of the aqueous epoxy polyamine resin (A) I. .
Curing agents II to IX obtained curing agents II to IX containing compound (B) according to the production method of the curing agent of Example 1 by the compound (B), blending ratio and mixing method shown in Table 5. . As the emulsifier in the curing agents II, IV, V, VIII, and IX, a nonionic emulsifier (manufactured by Nippon Emulsifier Co., Ltd., trade name “New Coal 740”) was used. Table 5 shows the viscosity at 25 ° C., the molecular weight, the number of functional groups, the acryloyl group equivalent and the properties (self-emulsifying property, water-insoluble property, water-soluble property) of the compound (B) used in each example. The characteristics of the compound (B) are as follows. At room temperature, 5 g of the compound (B) was added to 100 g of water, stirred for 3 minutes and allowed to stand. It was judged as "water-soluble", "water-soluble" if it was clear without precipitation, and "self-emulsifying" if it was turbid without precipitation. The specific gravity of the solid content in the curing agents II to IX was 1.2 g / cm ³ .
As an aminosilane coupling agent as the alkoxysilane compound (C), N-aminoethyl-γ-aminopropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name “KBM-603”) was used.

[Comparative Examples 1-3]
It replaces with 40 parts of hardening | curing agents I, and uses hardening | curing agent II with the compounding quantity shown in Table 3, and is the same as Example 1 except having set the compounding quantity of 4.8 parts of epoxysilane coupling agents to the compounding quantity shown in Table 3. In this way, an aqueous coating composition was obtained.

<Evaluation>
The aqueous coating composition obtained above was evaluated by the following method. The results are shown in Tables 2 and 3.
(Low temperature curability)
The aqueous coating composition obtained above was applied to a 20 cm × 30 cm grit blast steel plate using an applicator so that the film thickness of the dried coating film was 100 μm, and then an atmosphere having a relative humidity of 50% at 5 ° C. A test plate on which a coating film was formed was obtained by allowing it to stand for 16 hours.
With respect to the obtained coating film, a worker weighing 65 kg visually evaluated the state of the coating film after stepping on the coating film surface from the top with the heel of safety shoes for 30 seconds based on the following evaluation criteria. .
A: No peeling B: Little peeling C: Small part peeling D: Most peeling (pencil hardness)
A test plate was obtained in the same manner as in the evaluation of the low temperature curability. The pencil hardness of the coating film formed on the test plate was measured according to JISK5600-5-4.
(Initial rainfall resistance)
The aqueous coating composition obtained above was applied to a polished steel plate with a brush at a coating amount of 200 g / m ² and then dried in an environment of 5 ° C. for 24 hours to obtain a test plate. The test plate was immersed in water at 5 ° C., pulled up after 24 hours, and allowed to stand at 5 ° C. for 24 hours. Then, the appearance of the coating film was visually observed and evaluated based on the following criteria.
AA: Appearance abnormality is not recognized A: Some change in luster and color is recognized, but no cracking or swelling mark is observed C: Cracking or swelling mark is recognized (corrosion prevention evaluation A)
Each of a 7 cm × 15 cm grit blast steel plate, galvanized steel plate, aluminum steel plate and shop primer steel plate is spray-coated with the aqueous coating composition obtained above so that the dry film thickness becomes 100 μm, and is kept at 20 ° C. for 7 days. A test plate was obtained after standing. This test plate was tested for 200 hours with a salt spray test apparatus of JISK5600-7-1.
After that, an X-shaped cut that penetrates the coating film on the test piece and reaches each steel plate is made with a cutter knife, and a cellophane adhesive tape is stuck on it and peeled off. Adhesion between each steel plate and the coating film Was evaluated based on the same evaluation criteria as the low-temperature curability.
(Anti-corrosion evaluation B)
The adhesion between each steel sheet and the coating film was evaluated in the same manner as in the above-mentioned anticorrosion evaluation A, except that it was immersed in water at 40 ° C. for 336 hours instead of testing for 200 hours with the salt spray test apparatus of JISK5600-7-1. did.
(Evaluation of top coatability)
The shot paint blast steel sheet of 7 cm × 15 cm was spray-coated with the aqueous coating composition obtained above so that the dry film thickness was 95 to 105 μm, left at 20 ° C. for 7 days, and then exposed outdoors for 7 days.
In this way, five steel plates on which a coating film was formed were prepared. For each of the prepared steel plates, an oil-based paint (manufactured by Nippon Paint Marine Co., Ltd., trade name “CR Marine Finish”), solvent-based urethane paint (manufactured by Nippon Paint Marine Co., Ltd., trade name “Polyuremite Rack M”), solvent-based epoxy Paint (made by Nippon Paint Marine Co., Ltd., trade name “Epoxy Finish M”), water-based epoxy paint (made by Nihon Paint Marine Co., Ltd., trade name “Odemarine PF”) or water-based urethane paint (made by Nippon Paint Co., Ltd., trade name) "Eudeuretop") was spray-coated so that the dry film thickness was 35 to 45 µm, and left at 20 ° C for 7 days to obtain a test plate.
Except for obtaining the test plate as described above, the adhesion between each steel plate and the coating film formed from the aqueous coating composition obtained above was evaluated in the same manner as in the anticorrosion evaluation A.

  As is clear from the results of Examples 1 to 22, the aqueous coating composition of the present invention is excellent in low-temperature curability by containing the aqueous epoxy polyamine resin (A) and the compound (B). In addition, as is clear when Examples 1 to 21 and Comparative Example 1 are compared, the aqueous coating composition of the present invention contains a alkoxysilane compound (C), thereby providing a coating film with more excellent anticorrosion properties. Can be formed.

  Moreover, when Examples 1-22 and Comparative Example 3 are compared, when the content rate of an alkoxysilane compound (C) exists in a specific range, the outstanding low-temperature curability and corrosion resistance are obtained. . Further, as apparent from comparing Examples 1 to 21 and Comparative Example 2, when the equivalent ratio of the aqueous epoxy polyamine resin (A) and the compound (B) is in a specific range, the results are excellent. Low temperature curability and corrosion resistance are obtained.

  Further, as is clear from the results of Examples 12 to 16 and 20 to 22, the aqueous paint containing the aqueous epoxy polyamine resin (A) obtained by using the epoxy resin (a1) having an epoxy equivalent of 2000 to 3200. The composition can form a coating film that is remarkably excellent in initial rainfall resistance.

The aqueous coating composition of the present invention can be suitably applied as an anticorrosive coating to inner and outer plate portions of ships and underwater structures in seawater or fresh water. Specifically, it is suitably used for decks, hatch combing, upper frame parts, outer fence parts, engine rooms, residential areas, inner and outer parts of ships such as car hold; seawater or freshwater underwater structures such as piping materials, etc. obtain.

Claims (11)

An aqueous epoxy-based polyamine resin (A) having one or more primary amino groups and / or secondary amino groups in the molecule as a base coating liquid , and
A two-component aqueous coating composition comprising , as a curing agent, a compound (B) having one or more (meth) acryloyl groups in the molecule and an alkoxysilane compound (C),
The equivalent ratio ((meth) acryloyl group / amino group) of the amino group of the aqueous epoxy-based polyamine resin (A) and the (meth) acryloyl group of the compound (B) is 0.7 to 2.5,
The content of the alkoxysilane compound (C) is 0.2% by mass to 5% by mass in the solid content of the aqueous coating composition.
Water-based paint composition. The aqueous coating composition according to claim 1, wherein the aqueous epoxy polyamine resin (A) is water-dispersed. The aqueous coating composition of Claim 1 or 2 whose equivalent of the amino group of the said water-based epoxy-type polyamine resin (A) is 100-3000. The aqueous coating composition according to any one of claims 1 to 3 , wherein the aqueous epoxy polyamine resin (A) is obtained by amine-modifying an epoxy resin, and the epoxy equivalent of the epoxy resin is 180 to 3800. An aqueous epoxy polyamine resin (A1) obtained by amine modification of an epoxy resin (a1) having an epoxy equivalent of 400-1500 as the aqueous epoxy polyamine resin (A), and an epoxy having an epoxy equivalent of 2000-3200 The aqueous coating composition according to any one of claims 1 to 3 , comprising an aqueous epoxy polyamine resin (A2) obtained by amine-modifying the resin (a2). The water-based coating composition of Claim 5 whose mass ratio a1 / a2 of the said epoxy resin (a1) and the said epoxy resin (a2) is 8/2-2/8. The aqueous epoxy polyamine resin (A) is obtained by neutralizing an amino group of an epoxy polyamine resin with an acid, and the neutralization rate during the neutralization is 10% to 70%. The water-based coating composition according to any one of 6 . The water-based coating composition in any one of Claim 1 to 7 whose viscosity at 25 degrees C of the said compound (B) is 3000 mPa * s or less. The aqueous coating composition according to any one of claims 1 to 8 , further comprising a pigment, wherein the pigment volume concentration of the pigment is 20% to 50%. The coating-film formation method which coats the water-based coating composition in any one of Claim 1 to 9 on a substrate surface, and forms a coating film. The coating film forming method according to claim 10 , wherein a top coating layer is further formed on the coating film to form a top coating layer.