WO2011118791A1 - Method for forming coating film - Google Patents

Abstract

Disclosed is a method for forming a coating film, which has excellent curability at low temperatures. Specifically disclosed is a method for forming a coating film, which comprises a process wherein a coating film is formed by applying an aqueous coating composition over a base. The aqueous coating composition contains (A) an aqueous epoxy polyamine resin that has one or more first amino groups and/or second amino groups in each molecule and (B) a compound that has one or more (meth)acryloyl groups in each molecule. In a preferable embodiment of the present invention, the aqueous coating composition is a two pack type aqueous coating composition in which the main coating material liquid contains the aqueous epoxy polyamine resin (A) and the curing agent contains the compound (B).

Description

Coating method

The present invention relates to a method for forming a coating film.

Generally, 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 a method for forming a coating film having excellent low-temperature curability.

The method for forming a coating film of the present invention comprises coating a base material with an aqueous coating composition to form a coating film, wherein the aqueous coating composition contains one or more primary amino groups and / or in the molecule. Or the water-based epoxy-type polyamine resin (A) which has a 2nd amino group, and the compound (B) which has one or more (meth) acryloyl groups in a molecule | numerator are included.
In a preferred embodiment, the aqueous coating composition is a two-part aqueous coating composition, the main coating liquid contains the aqueous epoxy polyamine resin (A), and the curing agent contains the compound (B).
In preferable embodiment, the said water-based epoxy-type polyamine resin (A) is a water dispersion type.
In a preferred embodiment, the amino group equivalent of the aqueous epoxy polyamine resin (A) is 100 to 3000.
In a preferred embodiment, 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.
In a preferred embodiment, the water-based coating composition is a water-based epoxy polyamine resin (A) obtained by amine-modifying an epoxy resin (a1) having an epoxy equivalent of 400 to 1500 as the water-based epoxy polyamine resin (A). A1) and an aqueous epoxy polyamine resin (A2) obtained by amine-modifying an epoxy resin (a2) having an epoxy equivalent of 2000 to 3200.
In a preferred embodiment, a mass ratio a1 / a2 between the epoxy resin (a1) and the epoxy resin (a2) is 8/2 to 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 preferable embodiment, the molecular weight of the said compound (B) is 150-2000.
In a preferred embodiment, the method for forming a coating film of the present invention includes forming an overcoat layer on the coating film after the coating film is formed with the aqueous coating composition.
In a preferred embodiment, the method for forming a coating film of the present invention includes forming an intermediate coating layer after forming the coating film with the aqueous coating composition and before forming the top coating layer.
In a preferred embodiment, the coating film forming method of the present invention includes forming an undercoat layer on the substrate before forming a coating film with the aqueous coating composition.

According to the coating film forming method of the present invention, the aqueous epoxy polyamine resin (A) having one or more primary amino groups and / or second amino groups in the molecule, and one or more (meta ) By using the aqueous coating composition containing the compound (B) having an acryloyl group, a coating film exhibiting practical performance can be obtained even at a low temperature (for example, 5 ° C. or less). More specifically, the water-based coating composition uses a Michael addition reaction that is very reactive to the curing reaction, so that a cured coating film can be obtained even at a low temperature (for example, 5 ° C. or lower). Furthermore, when the water-based epoxy polyamine resin (A) is water-dispersed, the Michael addition reaction itself is a highly reactive reaction, but the stability of the water-based coating composition at room temperature is good. It is more workable than using a solvent-based coating composition. Furthermore, since an epoxy resin is used as a binder, a coating film having excellent corrosion resistance can be obtained.

A. Coating Film Forming Method The coating film forming method of the present invention includes coating a base material with an aqueous coating composition to form a coating film.

A-1. Overview of aqueous coating composition The aqueous coating composition includes 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 ( A compound (B) having a (meth) acryloyl group is included. The aqueous coating composition can form a coating film by mixing the aqueous epoxy polyamine resin (A) and the compound (B) to advance the curing reaction (Michael addition reaction) of these compounds. . Since the water-based epoxy polyamine resin (A) and the compound (B) can be cured at a low temperature (for example, 5 ° C.), the water-based coating composition is excellent in low-temperature curability.

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

The aqueous coating composition comprises (1) diluting the compound (B) with an organic solvent before mixing the aqueous epoxy polyamine resin (A) and the compound (B). (2) Compound (B) An emulsifier is mixed with the compound, or the compound (B) is emulsified or dispersed in water using a dispersant, an emulsifier or an aqueous resin, or (3) the compound (B) is an aqueous epoxy polyamine resin (A). A treatment such as dispersion in a dispersion of different resins may be performed. By performing such a treatment, the water-based epoxy polyamine resin (A) and the compound (B) can be mixed without using a special mixing apparatus, and the water-based epoxy polyamine resin (A) and the compound are excellent in dispersibility. An aqueous coating composition capable of efficiently reacting with (B) can be obtained.

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

Examples of the emulsifier used when the compound (B) is mixed with an emulsifier or when the compound (B) is emulsified or dispersed in water using a dispersant, an emulsifier, or an aqueous resin include, for example, a nonionic emulsifier and an anionic emulsifier. Etc. are 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 sodium polyacrylate salt, ammonium salt of styrene maleic acid copolymer half ester, polyethylene oxide adduct of styrene maleic acid copolymer half ester, and the like. As said aqueous resin, the soda salt of polyacrylic acid ester etc. are mentioned, for example. When the aqueous coating composition is a two-component type, the curing agent may contain the above-mentioned dispersant, emulsifier, or aqueous resin.

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, acrylic resin emulsions and dispersions, urethane resin emulsions and dispersions, Examples thereof include an aqueous epoxy polyamine resin having no primary amino group and no secondary amino group.

The content of the aqueous epoxy polyamine resin (A) as a solid content is preferably 5 to 95 mass%, more preferably 10 to 90 mass%, based on the total solid content of the aqueous coating composition. .

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

The equivalent ratio ((meth) acryloyl group / amino group) of the (meth) acryloyl group of the compound (B) to the amino group of the aqueous epoxy polyamine resin (A) is preferably 0.7 to 2.5. More preferably, it is 0.8 to 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.

The aqueous coating composition 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 titanium oxide, yellow iron oxide, red iron oxide, carbon black, phthalocyanine blue, phthalocyanine green, azo red, quinacridone red, benzimidazolone yellow, and the like; calcium carbonate, barium sulfate, kaolin, Examples include extender pigments such as clay, talc and mica; rust preventive pigments such as zinc phosphate and calcium 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 paint composition may contain water, a solvent or an additive. 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, 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 is used as a two-component aqueous coating composition, water, solvent and / or additive may be added to the main coating liquid or curing agent before mixing the main coating liquid and the curing agent. The main component coating liquid and the curing agent may be added after mixing. 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.

The aqueous coating composition may contain an alkoxysilane compound as an additive. By including the alkoxysilane compound, it is possible to form a coating film having excellent adhesion to the substrate.

Specific examples of the alkoxysilane compound include γ-glycidoxyalkyltrialkoxysilane such as γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, and γ-glycidoxypropoxytrimethoxysilane. Γ-aminopropyltrialkoxysilane such as γ-aminopropyltriethoxysilane and γ-aminopropyltripropoxysilane; N-phenyl-γ-aminopropyltrimethoxysilane, N-phenyl-γ-aminopropyltriethoxysilane, And N-phenyl-γ-aminoalkyltrialkoxysilane such as N-phenyl-γ-aminopropyltripropoxysilane. These may be used alone or in combination. These may be partially hydrolyzed and / or hydrolyzed and dehydrated.

When the alkoxysilane compound is included, the content thereof is preferably 0.3 to 3% by mass, more preferably 0.5 to 2% by mass, based on the total solid content of the aqueous coating composition.

A-2. Aqueous epoxy polyamine resin (A)
The aqueous coating composition contains an aqueous epoxy-based polyamine resin (A) having one or more primary amino groups and / or secondary amino groups in the molecule. The aqueous coating composition can form a coating film having excellent anticorrosion properties by including such a resin as a binder. In the present specification, “aqueous” is a concept including “water-soluble” and “water-dispersed”.

Preferably, the aqueous epoxy polyamine resin (A) is water-dispersed. If the water-dispersed water-based epoxy polyamine resin (A) is used, a coating film having excellent water resistance can be formed. Further, if the water-based epoxy polyamine resin (A) is water-dispersed, it can be easily mixed with the compound (B), and the reaction between the water-based epoxy polyamine resin (A) and the compound (B). It is possible to obtain an aqueous coating composition having a long pot life by suppressing rapid progress and adjusting the reactivity appropriately. 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 is difficult to proceed even at room temperature, and the stability and coatability are good. On the other hand, after 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 modifying an epoxy resin with an amine. 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.

The epoxy resin is preferably a bisphenol A type epoxy resin or a bisphenol F type epoxy resin, and particularly preferably a bisphenol A type epoxy resin.

The epoxy equivalent of the epoxy resin can be determined according to the desired film properties. It is preferably 180 to 3800, more preferably 400 to 3200, and particularly preferably 700 to 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 epoxy resin, there may be used those obtained by chain extension by using a reaction between an active hydrogen-containing compound capable of reacting with an epoxy group and an epoxy group to increase the molecular weight or modify the molecular weight. 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 appropriate 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 a compound having a functional group that reacts with an amino group in accordance with desired film properties. 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.

The amount of amino groups contained in the epoxy polyamine resin may be any appropriate amount of amino groups 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, the amine-modified epoxy resin) neutralized with an acid. 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.

Any appropriate molecular weight can be adopted as the molecular weight (number average) of the water-based epoxy polyamine resin (A) depending on the properties of the desired water-based coating composition or the physical properties of the coating film. Preferably, it is 500 to 20000 in terms of standard polystyrene using gel permeation chromatography (GPC), and more preferably 1000 to 10,000. 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 water-based paint composition may contain two or more water-based epoxy polyamine resins (A).

The aqueous coating composition is preferably an aqueous epoxy polyamine resin (A1) obtained by amine modification of the epoxy resin (a1) having an epoxy equivalent of 400 to 1500 as the aqueous epoxy polyamine resin (A). And an 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 of 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.

The characteristics of the aqueous coating composition or the physical properties of the coating film can be controlled by the molecular weight and amino group amount of the aqueous epoxy polyamine resin (A).

A-3. Compound (B)
The compound (B) used for the water-based coating composition 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 to 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 of the compound (B) at 25 ° C. is preferably 3000 mPa · s or less, more preferably 50 to 3000 mPa · s, particularly preferably 50 to 2200 mPa · s, and most preferably 50 to 1100 mPa · s. 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 Dimethacrylate, pentaerythritol diacrylate, pentaerythritol dimethacrylate, pentaerythritol triacrylate, pentaerythritol trimethacrylate, pentaerythritol tetraacrylate, pentaerythritol tetramethacrylate, glycerol diacrylate, glycerol dimethacrylate, glycerol acoxydi Methacrylate, 1,1,1-trishydroxymethylethane diacrylate, 1,1,1-trishydroxymethylethane dimethacrylate, 1,1,1-trishydroxymethylethane triacrylate, 1,1,1-tris Hydroxymethylethane trimethacrylate, 1,1,1-trishydroxymethylpropane diacrylate, 1,1, -Polymeric unsaturated monocarboxylic acid ester compounds of polyhydric alcohols such as trishydroxymethylpropane dimethacrylate; epoxy groups such as glycidyl acrylate or the reaction product of glycidyl methacrylate with acrylic acid, methacrylic acid, crotonic acid, maleic acid, etc. Examples thereof include adducts of an ethylenically unsaturated monomer and a carboxyl group-containing ethylenically unsaturated 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 stability and coatability are good. On the other hand, after 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) is self-emulsifying or water-insoluble. Can be mentioned.

Any appropriate method can be adopted as the method for making the heterogeneous state depending on the solubility of the compound (B) in water. For example, when compound (B) is water-soluble, compound (B) can be used as it is. In this case, the aqueous epoxy polyamine resin (A) is preferably a water-dispersed resin. On the other hand, when the compound (B) has a self-emulsifying property, the compound (B) is used as it is, or is used by emulsifying or dispersing in water with an emulsifier, a dispersant or an aqueous resin. can do. When the compound (B) is water-insoluble, it can be used after being emulsified or dispersed in water with an emulsifier, a dispersant or an aqueous resin. In these cases, the form of the aqueous epoxy polyamine resin (A) may be water-soluble or water-dispersed, but is preferably water-dispersed. 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.

The compound (B) can be modified with, for example, polyethylene oxide, and can be made water-soluble or self-emulsifiable by increasing the number of moles of ethylene oxide added to increase hydrophilicity.

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 self-emulsifying compound (B) include polyethylene glycol # 400 diacrylate (EO 9 mol), polyethylene glycol # 600 diacrylate (EO 14 mol), polyethylene glycol # 1000 diacrylate (EO 23 mol), ethoxylated bisphenol A di Examples include acrylate (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 water-insoluble compound (B) include polyethylene glycol # 200 glycol diacrylate (EO 4 mol), ethoxylated bisphenol A diacrylate (EO 3 mol), ethoxylated bisphenol A diacrylate (EO 4 mol), propoxylated bisphenol A di Acrylate (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 (PO2 mol), tripropylene glycol diacrylate (P 3 mol), polypropylene glycol # 400 diacrylate (PO 7 mol), polypropylene glycol # 700 diacrylate (PO 12 mol), ethoxylated trimethylolpropane triacrylate (EO 3 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 bisphenol A diacrylate ( PO4 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, tri Examples include propylene glycol dimethacrylate (PO3 mol), polypropylene glycol # 400 dimethacrylate (PO7 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). And a coating film having excellent low-temperature curability can be obtained. 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.

A-4. Method for applying aqueous coating composition The aqueous coating composition can be applied to any suitable substrate. Examples of the substrate include metal, wood, plastics, rubber, stone, slate, concrete, mortar, fiber, paper, glass, porcelain, earthenware, film, and composites thereof. For example, when the base material is an inorganic base material such as slate or concrete, a sealer may be coated on the surface in advance. Considering characteristics, it is preferably applied to metals. Examples of the metal include iron, copper, tin, zinc, aluminum, and stainless steel.

Examples of the object to be coated having metal on the surface (outer surface and inner surface) include, for example, buildings, ships, vehicles (for example, railway vehicles, large vehicles), aircraft, bridges, offshore structures, plants, tanks (for example, oil tanks). , Pipes, steel pipes, cast iron pipes and the like. In addition to the above, the coating film forming method of the present invention can also be used for buildings and civil engineering structures.

The coating method typically includes a method in which the water-based coating composition is applied to an object to be coated and dried. As a coating method, any appropriate method can be adopted depending on the type of the object (base material) to be coated. For example, application, immersion, etc. with a brush, a roller, air spray, airless spray, a trowel, etc. are mentioned.

The coating amount of the aqueous coating composition can be set to any appropriate coating amount depending on the application. Preferably, it is 10 to 350 g / m ² .

Any appropriate method can be adopted as the drying method. Natural drying or heat drying is preferred. In the case of natural drying, the drying time is preferably 2 hours or more, more preferably 24 hours or more, and particularly preferably 1 week or more. According to the method for forming a coating film of the present invention, a coating film having excellent anticorrosion properties can be formed even when dried at a low temperature (for example, 5 ° C. or less).

The thickness of the coating film formed by applying the aqueous coating composition is preferably 20 to 150 μm, more preferably 30 to 120 μm, as the thickness of the dry coating film. When the thickness of the dried coating film is thicker than 150 μm, there is a risk that problems such as sagging occur when forming the coating film.

The coating film obtained from the water-based coating composition has excellent anticorrosion properties. For example, in a portion that does not require weather resistance such as the inner surface of a bridge girder, the coating film alone can sufficiently cope.

B. Method for Forming Multilayer Coating Film Another coating film can be formed before and / or after the aqueous coating composition is applied to form a coating film. In one embodiment, after forming the coating film by applying the aqueous coating composition, a top coating layer is formed on the coating film to form a top coating layer. By forming the overcoat layer, the appearance, corrosion resistance and water-resistant adhesion are further improved.

Any appropriate paint can be adopted as the top coat. Examples include epoxy / amine-based paints, two-component urethane curable paints, one-component urethane curable paints, carbodiimide curable paints, acrylic resin-based paints, alkyd resin-based paints, and silicon resin-based paints. The top coat may be solvent-based or water-based. Preferably, it is aqueous. This is because the environmental load can be reduced. The top coating is more preferably an aqueous two-component urethane curable coating, an aqueous one-component urethane curable coating, an aqueous silicon resin-based coating, or an aqueous carbodiimide curable coating. Such a water-based paint has excellent weather resistance and can achieve long-term aesthetic protection.

The above-mentioned top coat layer is typically formed by applying a top coat and drying (heat treatment). Any appropriate method can be adopted as the coating method depending on the type of top coat. For example, application, immersion, etc. with a brush, a roller, air spray, airless spray, a trowel, etc. are mentioned.

The coating amount of the top coating can be set to any appropriate coating amount depending on the type of coating and the purpose of coating. Preferably, it is 30 to 400 g / m ² .

Any appropriate drying (heating) method may be employed as a method for drying (heating) the top coating material depending on the type of the top coating material. For example, natural drying, forced drying, baking, etc. are mentioned.

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. Preferably, it is 10 to 150 μm.

Before forming the coating film with the aqueous coating composition, an undercoat layer may be formed by applying an undercoat paint on the surface of the substrate. By forming the undercoat layer, it is more excellent in corrosion resistance and water-resistant adhesion, and can sufficiently cope with a case where high corrosion resistance such as a bridge, a plant, and a tank is required.

Any appropriate paint can be adopted as the undercoat paint. For example, an organic or inorganic zinc rich paint is mentioned. If such a paint containing zinc powder is used, an undercoat layer having extremely high anticorrosion properties can be formed. Further, since the paint has good workability, a uniform undercoat layer can be formed. The undercoat paint may be solvent-based or water-based. Preferably, it is aqueous. This is because the environmental load can be reduced.

As a method for forming the undercoat layer, a method similar to that for the overcoat layer may be employed. The application amount of the undercoat paint can be set to any appropriate application amount according to the type of paint and the purpose of painting. Preferably, it is 80 to 1200 g / m ² . The thickness of the undercoat layer can be set to any appropriate thickness depending on the type of paint and the purpose of painting. Preferably, it is 20 to 200 μm.

After forming the coating film by applying the aqueous coating composition, an intermediate coating layer may be formed by applying an intermediate coating on the coating film. By forming the intermediate coating layer, a coating film that is more excellent in corrosion resistance and water-resistant adhesion can be obtained. Preferably, the overcoat layer is formed on the intermediate coat layer.

Any appropriate paint can be adopted as the intermediate paint. For example, an epoxy / amine-based paint, a two-component urethane curable paint, a one-component urethane curable paint, and the like can be given. The intermediate coating may be solvent-based or water-based. Preferably, it is aqueous. This is because the environmental load can be reduced. The intermediate coating is more preferably a water-based epoxy / amine-based paint or a water-based two-component urethane curable paint. With such a water-based paint, the adhesiveness with the top coat layer is good and a strong multilayer coating film can be formed.

As the method for forming the intermediate coating layer, the same method as that for the top coating layer may be employed. The coating amount of the intermediate coating can be set to any appropriate coating amount depending on the type of coating and the purpose of coating. Preferably, it is 20 to 400 g / m ² . The thickness of the intermediate coating layer can be set to any appropriate thickness depending on the type of paint and the purpose of coating. Preferably, it is 10 to 100 μm.

The above-mentioned top coat, intermediate coat and undercoat can contain pigments, additives and the like. Examples of the pigment and additive include the pigment and additive described in the above section A-1. The number, type, and amount of pigments and additives to be added can be appropriately selected according to the purpose.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, parts and% in the examples are based on mass. Moreover, the evaluation items in the examples are as follows.

(Anti-corrosion)
The obtained coating film was subjected to a cyclic corrosion test defined in JIS K 5600 7-7, and the coating state after 120 cycles was evaluated based on the following criteria.
Ratio of generated rust area to obtained coating film area A: Less than 0.05% B: 0.05% or more and less than 0.1% (initial rainfall resistance)
The coating film was immersed in water at 5 ° C. together with the base material, 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 gloss and color is observed, but no cracking or swelling marks are observed. C: Cracking or swelling marks are observed (water-resistant adhesion)
The coated film is immersed in water at 20 ° C. together with the object to be coated and pulled up after 7 days. Then, according to the JIS K 5600-5.6 (2006) cross-cut method, a 3 mm × 3 mm grid is formed on the coated film. 5 × 5 pieces were prepared. After sticking the adhesive tape on the surface, it peeled off rapidly and evaluated based on the following reference | standard.
10 points: 1 cell does not peel off, and no peeling along the cut part is observed (peeling area: 0%)
8 points: There is no peeling of the squares, but peeling along some cuts is observed (peeling area: more than 0% and less than 5%)
6 points or less: Peeled squares are observed, or peeling along the cut portion is noticeable (peeling area: 5% or more)

<Production of water-based paint composition>
[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 to prepare a milky white aqueous (water-dispersed) epoxy-based polyamine resin (A) I.

[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 (trade name “Cardura E10-P” manufactured by Hexion Specialty Chemicals) 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 to prepare a milky white aqueous (water-dispersed) epoxy-based polyamine resin (A) II.

[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 (trade name “Cardura E10-P” manufactured by Hexion Specialty Chemicals) 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 became 40% by mass to prepare a milky white aqueous (water-dispersed) epoxy-based polyamine resin (A) III.

[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 to prepare a milky white aqueous (water-dispersed) epoxy polyamine resin (A) IV.

[Production Examples 5 to 7] Production of aqueous epoxy polyamine resins (A) V to VII Aqueous epoxy polyamine resins were produced 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.

[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 became 40% by mass, and a milky white aqueous (water-dispersed) epoxy polyamine resin (A) VIII 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.

[Production Example 11] Production of main component paint liquid I 110 parts of water, 32 parts of pigment dispersant (trade name “Disperbyk-190”, manufactured by Big Chemie), defoaming agent (trade name “BYK-019”, manufactured by Big Chemie) 4 parts, 179 parts of calcium carbonate (trade name “N heavy coal” manufactured by Maruo Calcium Co., Ltd.), 172 parts of titanium oxide (trade name “TI-PUR R706” manufactured by DuPont), calcium anticorrosive pigment (Toho Pigment Co., Ltd.) Manufactured, trade name "EXPERT NP1007") was mixed and stirred for 30 minutes with a disper to prepare a pigment dispersion paste. 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 (trade name “Adecanol UH-420” manufactured by Adeka) are added. In addition, mixing was performed to obtain a base coating material liquid I.

[Production Examples 12 to 18] Production of main agent coating liquids II to VIII Production Example 11 and Except that water-based epoxy polyamine resin (A) shown in Table 2 was used in place of water-based epoxy polyamine resin (A) I In the same manner, main agent paint liquids II to VII were obtained.

 

[Production Example 19] Production of curing agent I 40 parts of water, 10 parts of DPnB and polyethylene glycol # 400 dimethacrylate (EO 9 mol) as compound (B) (viscosity (25 ° C): 58 mPa · s, molecular weight: 508, number of functional groups: 2) , Acryloyl group equivalent: 254) 50 parts were mixed and stirred with a homogenizer for 10 minutes to obtain a curing agent I.

[Production Examples 20 to 28] Production of Curing Agents II to X Curing agents II to X containing compound (B) according to the method of Production Example 19 according to the compound (B), blending ratio and mixing method shown in Table 3 Got. As the emulsifier in the curing agents II, V, VIII, and IX, a nonionic emulsifier (trade name “New Coal 740” manufactured by Nippon Emulsifier Co., Ltd.) was used. Table 3 shows the viscosity, molecular weight, number of functional groups, acryloyl group equivalent and properties (self-emulsifying property, water-insoluble property, water-soluble property) of the compound (B) used in each production example at 25 ° C. 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.

 

[Production Examples 29 to 47] Production of water-based coating compositions 1 to 19 The main coating material liquid obtained in any of Production Examples 11 to 18 and the curing agent obtained in any of Production Examples 19 to 27, Aqueous coating compositions 1 to 19 were obtained by mixing in the blending amounts shown in Table 4 and stirring each with a disper for 10 minutes.

<Manufacture of top coat and intermediate coat>
[Production Example 48] Manufacture of water-based epoxy / amine coating A A charged with 34.5 parts of ion-exchanged water and 0.3 part of sodium alkyldiphenyl ether disulfonate (trade name “Perex SS-H” manufactured by Kao Corporation) in a nitrogen atmosphere The temperature was raised to 80 ° C. Next, 14 parts of styrene, 58 parts of 2-ethylhexyl acrylate, 22 parts of methyl methacrylate, 4 parts of ethylene glycol dimethacrylate, and 2 parts of methacrylic acid are contained as monomers, and 0.5 part of lauryl mercaptan is contained as a chain transfer agent. A monomer mixture was prepared. The acid value of the obtained monomer mixed solution was 13 mgKOH / g. This monomer mixture is added to an aqueous emulsifier solution in which 1.2 parts of sodium alkyldiphenyl ether disulfonate (trade name “Perex SS-H” manufactured by Kao Corporation) is dissolved in 50 parts of ion-exchanged water, and emulsified using a mixer. To prepare a pre-emulsion.
The pre-emulsion thus obtained and an aqueous initiator solution in which 0.3 part of ammonium persulfate was dissolved in 13 parts of ion-exchanged water were simultaneously added dropwise to the separable flask from a separate dropping funnel. The former started to drip evenly over 120 minutes and the latter over 150 minutes. After completion of the dropwise addition, the reaction was continued for an additional 120 minutes at the same temperature. After cooling, the solution was neutralized with aqueous ammonia corresponding to 10 mol% of the methacrylic acid used. The neutralized product was filtered through a 200 mesh wire mesh to obtain an acrylic emulsion resin.
Subsequently, 1.9 parts of a pigment dispersant (manufactured by Big Chemie, trade name “Disperbyk-190”), 0.3 part of an antifoaming agent (manufactured by Big Chemie, trade name “BYK-019”), titanium oxide 18.6 10.9 parts of calcium carbonate, 8.5 parts of talc, 2.9 parts of a rust preventive (manufactured by Kikuchi Color Co., Ltd., trade name “LF Bowsey PM-303W”), and 12.1 parts of water are mixed, Dispersed.
Here, 41 parts of emulsified epoxy resin (made by ADEKA, trade name “ADEKA RESIN EM-101-50”, epoxy equivalent: 500 g / equivalent, solid content 47%), film-forming aid (made by Chisso, trade name “CS”) -12 ") 1.7 parts, 0.4 parts of a rust preventive agent, 0.2 parts of an antifoaming agent and 17 parts of the previously prepared acrylic emulsion resin were mixed to obtain a base coating liquid.
Further, 8.9 parts of water-soluble polyamine resin sunmide (manufactured by Air Products and Chemicals, trade name “WH-910”, active hydrogen equivalent 135 g / equivalent (solid content conversion, solid content 60%)) and water 11. 2 parts were mixed to obtain a curing agent.
The said main ingredient coating liquid and the hardening | curing agent were mixed, and the water-based epoxy / amine type coating material A was obtained by stirring with a disper.

[Production Example 49] Production of water-based epoxy / amine-based paint B A water-based epoxy was prepared in the same manner as in Production Example 48, except that the main component paint solution was replaced with 17 parts of acrylic emulsion resin and 4 parts of acrylic emulsion resin. / Amine-based paint B was obtained.

[Production Example 50] Manufacture of water-based two-component urethane paint A 22 parts water, 6 parts pigment dispersant (manufactured by Big Chemie, trade name “Disperbyk-190”), 70 parts titanium oxide, defoaming agent (manufactured by Big Chemie) 1 part of a trade name “BYK-011”, diluted to 10%) and 0.4 part of a dimethylethanolamine aqueous solution (25% by mass) were mixed and stirred with a disper to obtain a pigment paste.
39 parts of the obtained pigment paste, 58 parts of an aqueous acrylic polyol (manufactured by DIC, trade name “Barnock WE-306”), 0.4 part of a surface conditioner (trade name “BYK-346”, trade name “BYK-346”), leveling 0.05 parts agent (BIC Chemie, trade name “BYK-333”), surfactant (air products, trade name “Dynol 604”) 0.4 parts, viscosity modifier (Rohm & Haas, 0.5 parts of the product name “Primal RM-8W”), 0.1 part of a dimethylethanolamine aqueous solution (25% by mass), and 2 parts of an antifoaming agent (manufactured by San Nopco, trade name “SN deformer 373”) Then, the main agent paint liquid was obtained by stirring with a disper.
17 parts of water-dispersible polyisocyanate (manufactured by DIC, trade name “Bernock DNW-5000”) was mixed with 100 parts of the above base coating liquid, and stirred with a disper to obtain an aqueous two-component urethane coating A. .

[Production Example 51] Production of water-based carbodiimide-based paint 100 parts of 4,4-dicyclohexylmethane diisocyanate was added at 170 ° C. in the presence of 1 part of carbodiimidization catalyst 3-methyl-1-phenyl-2-phospholene-1-oxide at 170 ° C. A time reaction was carried out to obtain a carbodiimide compound (isocyanate equivalent: 450 g / equivalent) having about 3 carbodiimide groups in one molecule and having isocyanate groups at both ends.
To 360 parts of a solution obtained by diluting this carbodiimide compound to 50% by mass with methyl isobutyl ketone, 0.02 part of dibutyltin laurate and 165 parts of polypropylene glycol having a molecular weight of 2000 were added and reacted at 85 ° C. for 1 hour. Subsequently, 125 parts of polyethylene glycol monomethyl ether having 15 repeating units was added and reacted at 85 ° C. for 1.5 hours.
After confirming disappearance of the isocyanate group with an infrared spectrophotometer, 920 parts of deionized water was added and stirred to homogenize. Under reduced pressure, methyl isobutyl ketone and water were distilled off at 40 ° C., and the active ingredient was adjusted to 40% by mass to obtain an aqueous carbodiimide curing agent having a carbodiimide equivalent of 825 g / equivalent.
Next, 6.8 parts of water, 1 part of pigment dispersant (trade name “Disperbyk-190” manufactured by Big Chemie), 1 part of ethylene glycol, 0.2 part of antifoaming agent, 2 parts of barium sulfate, and 24 parts of titanium oxide were added. 35 parts of pigment paste obtained by mixing and dispersing with a disper, 35 parts of an acrylic emulsion (acid value: 30 mgKOH / g, solid content: 55% by mass), water-soluble acrylic resin (acid value: 55 mgKOH / g, hydroxyl value: 70 mgKOH) / G, weight average molecular weight: 9000, solid content: 30% by mass) 8 parts, film forming aid (trade name “CS-12”, manufactured by Chisso Corporation), 3 parts, viscosity agent 1 part, antifoaming agent 1 part, Was added to obtain a base paint liquid.
An aqueous carbodiimide-based paint was obtained by adding 35 parts of the previously prepared aqueous carbodiimide curing agent to the obtained main coating liquid and stirring with a disper.

<Manufacture of undercoat>
[Production Example 52] Production of water-based organic zinc-rich paint Water-soluble polyamine resin (manufactured by Air Products and Chemicals, trade name “Sunmide WH-910”, active hydrogen equivalent 135 g / equivalent (solid content conversion), solid content 60%) 8.8 parts, 1.2 parts of a viscosity agent, and 6 parts of water were mixed to obtain a curing agent.
Mix the above curing agent with 16 parts of emulsified epoxy resin (made by ADEKA, trade name “ADEKA RESIN EM-101-50”, epoxy equivalent 500 g / equivalent, solid content 47%) and 68 parts of zinc powder, and stir with a disper. Thus, an aqueous organic zinc rich paint was obtained.

[Example 1] Formation of single-layer coating film
24 hours after preparing the aqueous coating composition 1 by the method of Production Example 29 in an environment of 30 ° C., the aqueous coating composition 1 was applied to the sandblasted steel plate with a brush so that the coating amount was 200 g / m ^2. Then, it was dried in an environment of 20 ° C. for 7 days to form a single layer coating film (thickness after drying: 60 μm) formed of the aqueous coating composition 1. At this time, the aqueous coating composition 1 was not gelled and could be applied with good workability. About the obtained single layer coating film, the above "corrosion resistance" was evaluated. The evaluation results are shown in Table 4.

[Examples 2 to 19] Formation of single-layer coating film A single-layer coating film was obtained in the same manner as in Example 1 except that the aqueous coating composition shown in Table 4 was used instead of the aqueous coating composition 1. . In any of the examples, the aqueous coating composition 24 hours after preparation was used, but none of the aqueous coating composition was gelled. The obtained single-layer coating film was subjected to the same evaluation as in Example 1. The evaluation results are shown in Table 4.

[Example 20] Formation of single-layer coating film Aqueous coating composition 1 was prepared by the method of Production Example 29 in an environment of 5 ° C, and after 1 hour, the aqueous coating composition 1 was applied to a polished steel sheet in an amount of 200 g. / M ² was applied with a brush and dried in an environment of 5 ° C. for 24 hours to form a single-layer coating film (thickness after drying: 60 μm) formed of the aqueous coating composition 1. At this time, the aqueous coating composition 1 was not gelled and could be applied with good workability. About the obtained coating film, the above-mentioned "initial rainfall resistance" was evaluated. The evaluation results are shown in Table 4.

[Examples 21 to 38] Formation of single-layer coating film A single-layer coating film was obtained in the same manner as in Example 20, except that the aqueous coating composition shown in Table 4 was used instead of the aqueous coating composition 1. . In any of the examples, the aqueous coating composition that had passed 1 hour after preparation was used, but none of the aqueous coating compositions gelled. The obtained single-layer coating film was subjected to the same evaluation as in Example 20. The evaluation results are shown in Table 4.

[Example 39] Formation of single-layer coating film Polished steel sheet prepared by preparing the aqueous coating composition 1 by the method of Production Example 29 in an environment of 23 ° C and defatting the aqueous coating composition 1 with xylene after 24 hours. A single-layer coating film (60 μm in thickness after drying) formed by the aqueous coating composition 1 is applied with a brush so that the coating amount is 200 g / m ² and dried for 7 days in an environment of 23 ° C. Formed. At this time, the aqueous coating composition 1 was not gelled and could be applied with good workability. About the obtained coating film, said "water-resistant adhesion" was evaluated. The evaluation results are shown in Table 4.

[Examples 40 to 57] Formation of a single-layer coating film A single-layer coating film was obtained in the same manner as in Example 39 except that the aqueous coating composition shown in Table 4 was used instead of the aqueous coating composition 1. . In any of the examples, the aqueous coating composition 24 hours after preparation was used, but none of the aqueous coating composition was gelled. The obtained single-layer coating film was subjected to the same evaluation as in Example 39. The evaluation results are shown in Table 4.

 

[Example 58] Formation of multilayer coating film (two layers)
A polished steel plate degreased with xylene was used as the substrate. In an environment of 5 ° C., the aqueous coating composition 12 obtained in Production Example 40 was applied to the substrate using a brush at an application amount of 200 g / m ² , and then dried for 24 hours in the same environment as the application. Thus, a coating film (thickness after drying: 60 μm) formed from the aqueous coating composition I was obtained. The obtained coating film had no touch feeling (specifically, no stickiness), and it was possible to apply a top coating.
A coating amount of a solvent-type epoxy / amine-based paint A (trade name “Epotal NB-20”, manufactured by Nippon Paint Co., Ltd.) is used as a top coating paint in an environment of 5 ° C. in an environment of 5 ° C. After coating at 200 g / m 2, it was dried at 25 ° C. for 24 hours to form an overcoat layer (thickness after drying 60 μm) to obtain a multilayer coating film (two layers).
The obtained “multilayer coating film (2 layers)” was evaluated for the “water adhesion”. The evaluation results are shown in Table 5.

[Examples 59 to 68] Formation of multi-layer coating film (two layers) Using the substrate, aqueous coating composition and top coating composition shown in Table 5, the method described in Example 58 was carried out under the conditions shown in Table 5. A multilayer coating film (2 layers) was obtained in the same manner. The top coating materials shown in Table 5 used in Examples 59 to 68 are as follows. In addition, the polished steel plate used in Example 59 was previously degreased with xylene, and the slate plate used in Example 65 was previously provided with an aqueous sealer for inorganic materials (manufactured by Nippon Paint Co., Ltd. The name “Ultra Sealer III”) is applied.
None of the coating films formed from the aqueous coating composition had a touch feeling (specifically, there was no stickiness), and it was possible to apply a top coating.
Further, the obtained multilayer coating film (two layers) was subjected to the same evaluation as in Example 58. The evaluation results are shown in Table 5.
[Top coat]
1. Solvent type epoxy / amine paint A
As a solvent-type epoxy / amine paint A, a product name “Epotal NB-20” manufactured by Nippon Paint Co., Ltd. was used.
2. Solvent two-component urethane paint A
As the solvent two-component urethane-based paint A, Nippon Paint Co., Ltd. trade name “Hypon 50 Fine” was used.
3. Solvent two-component urethane paint B
As the solvent two-component urethane-based paint B, Nippon Paint Co., Ltd., trade name “Nippure Top Eco” was used.
4). Water-based epoxy / amine paint A
As the water-based epoxy / amine-based paint A, the water-based epoxy / amine-based paint A produced in Production Example 48 was used.
5. Aqueous two-component urethane paint A
As the aqueous two-component urethane-based paint A, the aqueous two-component urethane-based paint A produced in Production Example 50 was used.
6). Water-based emulsion-based paint As a water-based emulsion-based paint, a product name “Odecoat G” manufactured by Nippon Paint Co., Ltd. was used.
7). Aqueous carbodiimide-based paint The aqueous carbodiimide-based paint produced in Production Example 51 was used as the aqueous carbodiimide-based paint.

 

[Example 69] Formation of multilayer coating film (four layers)
Apply a solvent-type organic zinc rich paint (trade name “N Zinky 8000HB”, manufactured by Nippon Paint Co., Ltd.) as an undercoat on the sandblasted steel sheet to a thickness of 70 μm after drying to form an undercoat layer. It was.
Thereafter, the aqueous coating composition 13 obtained in Production Example 41 was applied onto the undercoat layer with a brush so that the thickness after drying was 60 μm in an environment of 5 ° C., and then the same environment as that applied. The coating film formed with the aqueous coating composition 13 was obtained by drying for 1 day.
A thickness of 30 μm after drying solvent-type epoxy / amine-based paint B (made by Nippon Paint Co., Ltd., trade name “Hypon 30 Fine Intermediate Coating”) as an intermediate coating under an environment of 25 ° C. in an environment of 25 ° C. After coating with a brush, the coating was dried for 1 day under the same environment as that for coating to obtain an intermediate coating layer.
On the intermediate coating layer, in a 25 ° C. environment, a solvent two-component urethane coating material A (manufactured by Nippon Paint Co., Ltd., trade name “Hypon 50 Fine”) as a top coating material is dried to a thickness of 30 μm. After applying by air spraying, it was dried for 7 days under the same environment as at the time of application to form an overcoat layer to obtain a multilayer coating film (4 layers).
The obtained “multilayer coating film (4 layers)” was evaluated for “water resistance” and “corrosion resistance”. The evaluation results are shown in Table 6.

[Example 70] Formation of multi-layer coating film (four layers) Multi-layer coating was carried out in the same manner as in Example 69 except that the undercoat paint, water-based paint composition, intermediate coat paint and top coat paint shown in Table 6 were used. A membrane (4 layers) was obtained. The undercoat paint, intermediate coat paint and top coat paint shown in Table 6 used in Example 70 are as follows.
The obtained multilayer coating film (4 layers) was subjected to the same evaluation as in Example 69. The evaluation results are shown in Table 6.
[Undercoating paint]
The aqueous organic zinc rich paint obtained in Production Example 52 was used.
[Intermediate paint]
As the water-based epoxy / amine-based paint B, the water-based epoxy / amine-based paint B obtained in Production Example 49 was used.
[Top coat]
The water-based carbodiimide-based paint produced in Production Example 51 was used as the water-based carbodiimide-based paint.

 

[Comparative Example 1]
The same procedure as in Example 58 except that solvent-based epoxy / amine-based paint A (trade name “Epotal NB-20” manufactured by Nippon Paint Co., Ltd.) was used in place of the aqueous paint composition 12 obtained in Production Example 40. Thus, a coating film formed of the solvent-type epoxy / amine-based paint A on the substrate was obtained. The obtained coating film was sticky and was not in a state where a top coating material could be applied.

As shown in Examples 1 to 19, according to the method for forming a coating film of the present invention, a coating film having excellent corrosion resistance could be obtained.

As shown in Examples 1 to 19 and 39 to 57, when the water-dispersed water-based epoxy polyamine resin (A) is used, the water-based coating composition stored for a long time does not gel and has excellent workability. And the coating film which was excellent in anticorrosion property was able to be formed.

As shown in Examples 20 to 38, 58, 60 and 62, the coating film formed by the coating film forming method of the present invention exhibited sufficient curability even at low temperatures. On the other hand, as shown in Comparative Example 1, the coating film formed from the conventional epoxy / amine-based paint had insufficient curability at low temperatures.

As shown in Examples 31 to 35, by using an aqueous coating composition containing an aqueous epoxy polyamine resin (A) obtained using an epoxy resin (a1) having an epoxy equivalent of 2000 to 3200, It is possible to form a coating film that is more excellent in rainability. Further, as shown in Examples 31, 32, 34, 35, 50, 51, 53 and 54, an aqueous epoxy polyamine resin (A1) obtained from an epoxy resin (a1) having an epoxy equivalent of 400 to 1500; By using an aqueous coating composition containing an aqueous epoxy polyamine resin (A2) obtained from an epoxy resin (a2) having an epoxy equivalent of 2000 to 3200 at a specific mass ratio (a1 / a2), It is possible to form a coating film that is excellent in rainfall and water adhesion.

As shown in Examples 58 to 68, the coating film forming method of the present invention was able to obtain a coating film having excellent water resistance adhesion by forming a topcoat layer.

As shown in Examples 69 and 70, the coating film forming method of the present invention was able to obtain a coating film excellent in water resistance and corrosion resistance by forming an undercoat layer, an intermediate coat layer and an overcoat layer. .

The coating-film formation method of this invention can be used suitably for an anticorrosion use, for example. Specifically, in addition to ships, vehicles (eg, railway vehicles, large vehicles), aircraft, bridges, offshore structures, plants, tanks (eg, oil tanks), pipes, steel pipes, cast iron pipes, doors, window frames, etc. It can be suitably used for a metal part included in a building.

Claims (13)

1. Coating a substrate with an aqueous coating composition to form a coating film,
   The aqueous coating composition is
   An aqueous epoxy-based polyamine resin (A) having one or more primary amino groups and / or secondary amino groups in the molecule;
   A compound (B) having one or more (meth) acryloyl groups in the molecule,
   Coating film forming method.
2. The aqueous coating composition is a two-component aqueous coating composition;
   The coating-film formation method of Claim 1 with which a main ingredient coating liquid contains the said water-based epoxy-type polyamine resin (A), and a hardening | curing agent contains the said compound (B).
3. The coating film forming method according to claim 1 or 2, wherein the aqueous epoxy polyamine resin (A) is a water-dispersed type.
4. The method for forming a coating film according to any one of claims 1 to 3, wherein an equivalent of an amino group of the aqueous epoxy polyamine resin (A) is 100 to 3000.
5. The method for forming a coating film according to any one of claims 1 to 4, wherein the aqueous epoxy-based polyamine resin (A) is obtained by amine-modifying an epoxy resin, and the epoxy equivalent of the epoxy resin is 180 to 3800.
6. An aqueous epoxy polyamine resin (A1) obtained by amine-modifying an epoxy resin (a1) having an epoxy equivalent of 400 to 1500 as the aqueous epoxy polyamine resin (A), and the epoxy equivalent of the aqueous coating composition. The coating film forming method according to any one of claims 1 to 4, further comprising an aqueous epoxy polyamine resin (A2) obtained by amine-modifying an epoxy resin (a2) having a molecular weight of 2000 to 3200.
7. The coating film forming method according to claim 6, wherein a mass ratio a1 / a2 between the epoxy resin (a1) and the epoxy resin (a2) is 8/2 to 2/8.
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%. 8. The method for forming a coating film according to any one of 7 above.
9. The method for forming a coating film according to any one of claims 1 to 8, wherein the viscosity of the compound (B) at 25 ° C is 3000 mPa · s or less.
10. The coating film forming method according to any one of claims 1 to 9, wherein the molecular weight of the compound (B) is 150 or more and 2000 or less.
11. The method for forming a coating film according to any one of claims 1 to 10, comprising forming an overcoat layer on the coating film after the coating film is formed with the aqueous coating composition.
12. 12. The method of forming a coating film according to claim 11, comprising forming an intermediate coating layer after forming the coating film with the aqueous coating composition and before forming the top coating layer.
13. The method of forming a coating film according to any one of claims 1 to 12, comprising forming an undercoat layer on the substrate before forming the coating film with the aqueous coating composition.