JP5512981B2 - Water-based paint composition and coating method using the composition - Google Patents

Description

  The present invention relates to an aqueous coating composition capable of forming a coating film excellent in storage stability of a coating material and having excellent corrosion resistance, water resistance, and the like, and a coating method using the composition.

  Conventionally, metal surfaces of structures such as building interiors and exteriors, bridges, ships, plant facilities, steel towers are generally coated with epoxy resin or alkyd resin rust-preventive paint, then alkyd resin paint, acrylic alkyd resin paint, A top coating such as a silicon alkyd resin coating is applied (for example, see Patent Document 1). On the other hand, from the viewpoint of environmental protection and improvement of the working environment, in various paint fields, the transition from organic solvent-based paints to water-based paints is underway. ing.

  However, the water-based anti-rust paints that have been used for the above-mentioned coatings have low gloss and are limited in coloration, are prone to choking outdoors, require the application of a top coat, and have a high anti-corrosion property. In order to ensure rustability, it was necessary to add a rust preventive pigment. Conventionally, chromic acid-based or lead-based rust-preventing pigments have been used as rust-preventing pigments, but their use is regulated in terms of environmental protection and safety. Various non-chromium rust preventive pigments such as phosphoric acid pigments, phosphorous acid pigments, molybdic acid pigments, boric acid pigments, cyanamide pigments are proposed, and various water-based paints using them are also proposed. (For example, Patent Document 2 to Patent Document 5).

JP 2001-293433 A JP 2003-286437 A Japanese Patent Laid-Open No. 2001-19904 JP 2002-53769 A JP 2005-279318 A

  However, many of these non-chromium rust preventive pigments are dissolved in moisture entering from the outside as their characteristics, and many exhibit a rust preventive effect by eluting various ions with metal ions and chelating power, When such a non-chromium rust preventive pigment is blended in the water-based paint, the eluted ionic components may inhibit the stability of the water-based paint and cause thickening or gelation.

  An object of the present invention is to provide an aqueous coating composition capable of forming a coating film excellent in storage stability of a coating material and having excellent corrosion resistance, water resistance, and the like, and a coating method using the composition.

  The present invention relates to (B) the general formula (1) with respect to 100 parts by mass (solid content) of the aqueous film-forming resin (A).

[Wherein, R ¹ represents a monovalent organic group having 4 to 22 carbon atoms. R ² represents a hydrocarbon group having 4 to 22 carbon atoms, an acyl group having 4 to 22 carbon atoms, or

(In the formula, R ⁴ represents an alkylene group having 2 to 10 carbon atoms, and n represents an integer of 0 to 100. When n is 2 or more, a plurality of R ⁴ may be the same or different. .) R ³ represents an alkylene group having 2 to ³ carbon atoms. m shows the integer of 2-100. The plurality of R ³ may be the same or different. 1 to 20 parts by mass (solid content) of a nitrogen-containing compound represented by the formula (1) and (C) 1 to 80 parts by mass of a rust preventive pigment not containing chromium and lead, In addition, the present invention relates to a coating method characterized by coating the aqueous coating composition on the surface of a metal substrate or an old painted surface on the metal substrate.

  According to the present invention, by blending the above-mentioned non-chromium rust preventive pigment in combination with a specific nitrogen-containing compound, coating having excellent corrosion resistance, water resistance, etc. without impairing the storage stability of the paint. It is possible to form a film.

  The aqueous coating composition of the present invention contains the aqueous film-forming resin (A) as an essential component.

  As the aqueous film-forming resin (A), various conventionally known aqueous film-forming resins can be used without any particular limitation. For example, epoxy resin-based, alkyd resin-based, acrylic resin-based, urethane resin-based, polyester resin-based resin can be used. And at least one selected from silicon resin systems.

  Of these, the aqueous fatty acid-modified acrylic resin (A1) is an aqueous film-forming resin (A1) from the viewpoint of anticorrosion and water resistance of the obtained coating film and from the point that the content of volatile organic solvent (VOC) can be reduced. ).

  Examples of the aqueous fatty acid-modified acrylic resin (A1) include a fatty acid (a), an epoxy group-containing polymerizable unsaturated monomer (b), an acid group-containing polymerizable unsaturated monomer (c), and an alkyl group having 4 or more carbon atoms. A resin containing a structural unit derived from the polymerizable unsaturated monomer (d) having the above and other polymerizable unsaturated monomer (e) is preferred.

  Examples of the fatty acid (a) include those having a structure in which a carboxyl group is bonded to the end of a hydrocarbon chain, and examples include dry oil fatty acids, semi-dry oil fatty acids, and non-dry oil fatty acids. Dry oil fatty acids and semi-dry oil fatty acids are not strictly distinguishable, but in general, dry oil fatty acids are unsaturated fatty acids that are iodinated 130 or more, and semi-dry oil fatty acids are 100 or more and less than 130 iodinated. Of unsaturated fatty acids. Non-drying oil fatty acids are generally unsaturated fatty acids having an iodine value of less than 100. Examples of the dry oil fatty acid and semi-dry oil fatty acid include fish oil fatty acid, dehydrated castor oil fatty acid, safflower oil fatty acid, linseed oil fatty acid, soybean oil fatty acid, sesame oil fatty acid, poppy oil fatty acid, eno oil fatty acid, hemp oil fatty acid, grape Examples include kernel oil fatty acid, corn oil fatty acid, tall oil fatty acid, sunflower oil fatty acid, cottonseed oil fatty acid, walnut oil fatty acid, rubber seed oil fatty acid, etc. Non-drying oil fatty acids include, for example, coconut oil fatty acid, hydrogenated coconut oil fatty acid , Palm oil fatty acids and the like, and these can be used alone or in combination of two or more. Further, caproic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid and the like can be used in combination.

  In the present invention, as the fatty acid (a), it is preferable to use a dry oil fatty acid and / or a semi-dry oil fatty acid because it is excellent in oxidative curability and gas barrier properties of the formed coating film.

  Examples of the epoxy group-containing polymerizable unsaturated monomer (b) include those having one epoxy group and one polymerizable unsaturated bond in one molecule, such as glycidyl (meth) acrylate, β-methyl. Examples include glycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, 3,4-epoxycyclohexylethyl (meth) acrylate, 3,4-epoxycyclohexylpropyl (meth) acrylate, and allyl glycidyl ether. These can be used alone or in combination of two or more.

  Examples of the acid group-containing polymerizable unsaturated monomer (c) include those having one acid group and one polymerizable unsaturated bond in one molecule, such as (meth) acrylic acid, maleic acid, Polymerizable unsaturated monomer having a carboxyl group such as crotonic acid and β-carboxyethyl acrylate; polymerization having at least one group selected from the group consisting of sulfonic acid group, sulfonic acid group, phosphoric acid group and phosphate group Unsaturated unsaturated monomers.

Examples of the polymerizable unsaturated monomer (d) having an alkyl group having 4 or more carbon atoms include n-butyl (meth) acrylate, i-butyl (meth) acrylate, tert-butyl (meth) acrylate, and n-hexyl. (Meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, tridecyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate and “isostearyl acrylate” (product) _C18 -alkyl (meth) acrylate, cyclohexyl (meth) acrylate, methylcyclohexyl (meth) acrylate, t-butylcyclohexyl (meth) acrylate, cyclododecyl (name, manufactured by Osaka Organic Chemical Co., Ltd.) Meta) Acryle It can be mentioned alkyl or cycloalkyl (meth) acrylates of bets like. These can be used alone or in combination of two or more. Among these polymerizable unsaturated monomers (d), in particular, as at least a part thereof, a polymerizable unsaturated monomer having a linear or branched hydrocarbon group having 6 or more carbon atoms and / or a cycloalkyl group Preferred are those comprising a polymerizable unsaturated monomer having

  The other polymerizable unsaturated monomer (e) is a monomer component copolymerizable with the monomer (b), (c) and / or (d) described above, and examples thereof include methyl (meth) acrylate, ethyl ( Alkyl (meth) acrylates such as meth) acrylate, n-propyl (meth) acrylate and i-propyl (meth) acrylate; polymerizable unsaturated monomers having an isobornyl group such as isobornyl (meth) acrylate; adamantyl (meth) acrylate and the like A polymerizable unsaturated monomer having an adamantyl group; vinyl aromatic compounds such as styrene, α-methylstyrene, vinyltoluene; vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane, γ- (meta ) Acryloyloxypropyltrimethoxysilane Polymerizable unsaturated monomers having an alkoxysilyl group such as γ- (meth) acryloyloxypropyltriethoxysilane; perfluoroalkyl (meth) such as perfluorobutylethyl (meth) acrylate and perfluorooctylethyl (meth) acrylate Acrylate; Polymerizable unsaturated monomer having alkyl fluorine group such as fluoroolefin; Polymerizable unsaturated monomer having photopolymerizable functional group such as maleimide group; 1,2,2,6,6-pentamethylpiperidyl (meth) Acrylate, 2,2,6,6-tetramethylpiperidinyl (meth) acrylate, etc .; vinyl compounds such as N-vinylpyrrolidone, ethylene, butadiene, chloroprene, vinyl propionate, vinyl acetate; (meth) acrylonitrile, (meta ) Acrylamide, dimethyl Nitrogen-containing polymerizable unsaturated monomers such as ruaminopropyl (meth) acrylamide, dimethylaminoethyl (meth) acrylate, and addition products of glycidyl (meth) acrylate and amines; 2-hydroxyethyl (meth) acrylate, C2-C8 hydroxyalkyl ester of (meth) acrylic acid such as 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, allyl alcohol, the above (Meth) acrylate having a hydroxyl group such as a modified ε-caprolactone of a hydroxyalkyl ester of (meth) acrylic acid; a polymerizable unsaturated having a hydroxyl group such as (meth) acrylate having a polyoxyethylene chain having a hydroxyl group at the molecular end Monomer: molecular end is al (Meth) acrylate having a polyoxyethylene chain which is a xy group; 2-hydroxy-4- (3-methacryloyloxy-2-hydroxypropoxy) benzophenone, 2-hydroxy-4- (3-acryloyloxy-2-hydroxypropoxy) ) Benzophenone, 2,2′-dihydroxy-4- (3-methacryloyloxy-2-hydroxypropoxy) benzophenone, 2,2′-dihydroxy-4- (3-acryloxy-2-hydroxypropoxy) benzophenone, 2,4 -Addition reaction product of hydroxybenzophenones such as dihydroxybenzophenone and 2,2 ', 4-trihydroxybenzophenone and glycidyl (meth) acrylate; 2- (2'-hydroxy-5'-methacryloyloxyethylphenyl) -2H -Be Polymerizable unsaturated monomer having ultraviolet absorbing functional group such as zotriazole; 4- (meth) acryloyloxy-1,2,2,6,6-pentamethylpiperidine, 4- (meth) acryloyloxy-2,2 , 6,6-tetramethylpiperidine, 4-cyano-4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 1- (meth) acryloyl-4- (meth) acryloylamino-2, 2,6,6-tetramethylpiperidine, 1- (meth) acryloyl-4-cyano-4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 4-crotonoyloxy-2,2 , 6,6-tetramethylpiperidine, 4-crotonoylamino-2,2,6,6-tetramethylpiperidine, 1-crotonoyl-4-crotono UV-stable polymerizable unsaturated monomers such as ruoxy-2,2,6,6-tetramethylpiperidine; acrolein, diacetone acrylamide, diacetone methacrylamide, acetoacetoxyethyl methacrylate, formylstyrol, vinyl having 4 to 7 carbon atoms Polymerizable unsaturated monomers having a carbonyl group such as alkyl ketones (for example, vinyl methyl ketone, vinyl ethyl ketone, vinyl butyl ketone); allyl (meth) acrylate, ethylene glycol di (meth) acrylate, tri Ethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, 1, 4-butanediol- (meta) a Acrylate, neopentyl glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tetra (meth) Acrylate, glycerol di (meth) acrylate, 1,1,1-trishydroxymethylethanedi (meth) acrylate, 1,1,1-trishydroxymethylethanetri (meth) acrylate, 1,1,1-trishydroxymethylpropane tri (meth) acrylate, triallyl isocyanurate, diallyl terephthalate, divinylbenzene, etc. have at least two polymerizable unsaturated groups in one molecule Polyvinyl compounds, etc. are mentioned, and these are selected as appropriate according to the performance desired for the resin to be formed, alone or in combination of two or more. Not to be able to use.

  The aqueous fatty acid-modified acrylic resin comprises the fatty acid (a), the epoxy group-containing polymerizable unsaturated monomer (b), the acid group-containing polymerizable unsaturated monomer (c), and the alkyl group having 4 or more carbon atoms. It can be obtained by copolymerizing the polymerizable unsaturated monomer (d) and other polymerizable unsaturated monomer (e). The proportion of each component used at that time can be as follows based on the total amount of components (a), (b), (c), (d) and (e).

Component (a): 0.5 to 45% by mass, preferably 3 to 42% by mass, particularly preferably 7 to 40% by mass,
Component (b): 0.3 to 20% by mass, preferably 1.5 to 18.5% by mass, particularly preferably 3.5 to 16.5% by mass,
Component (c): 0.1 to 5% by mass, preferably 0.3 to 4.5% by mass, particularly preferably 0.5 to 4.0% by mass,
Component (d): 20 to 95% by mass, preferably 25 to 85% by mass, particularly preferably 30 to 75% by mass,
Component (e): 4.1-79.1% by mass, preferably 10.2-70.2% by mass, particularly preferably 14-69% by mass.

  The fatty acid-modified acrylic resin is preferably firstly subjected to an addition reaction between the fatty acid (a) and the epoxy group-containing polymerizable unsaturated monomer (b), and then the resulting fatty acid-modified polymerizable unsaturated monomer is converted to an acid group-containing It can be produced by copolymerizing with a polymerizable unsaturated monomer (c), a polymerizable unsaturated monomer (d) having an alkyl group having 4 or more carbon atoms, and other polymerizable unsaturated monomers (e).

  In the production of the above-mentioned fatty acid-modified polymerizable unsaturated monomer, the fatty acid (a) and the epoxy group-containing polymerizable unsaturated monomer (b) are a carboxyl group-to-epoxy group-containing polymerizable unsaturated monomer (b) in the fatty acid (a). ) In the ratio of 0.75: 1 to 1.25: 1, preferably 0.8: 1 to 1.2: 1. Is preferred.

  The reaction between the fatty acid (a) and the polymerizable unsaturated monomer (b) having an epoxy group is in accordance with a normal method without causing a reaction problem such as gelation in the presence of a polymerization inhibitor described later. The reaction can be carried out under conditions such that the carboxyl group in the fatty acid component and the epoxy group in the epoxy group-containing polymerizable unsaturated monomer can react smoothly, and usually from about 100 to about 180 ° C. It is suitable to carry out under the condition of heating for about 10 hours.

  In this reaction, for example, an esterification catalyst such as a tertiary amine such as N, N-dimethylaminoethanol, a quaternary ammonium salt such as tetraethylammonium bromide, tetrabutylammonium bromide, etc. can be used. An inert organic solvent may be present.

  Examples of the polymerization inhibitor include hydroxy compounds such as hydroquinone, hydroquinone monomethyl ether, pyrocatechol and p-tert-butylcatechol; nitrobenzene, nitrobenzoic acid, o-, m- or p-dinitrobenzene, 2,4- Nitro compounds such as dinitrotoluene, 2,4-dinitrophenol, trinitrobenzene, picric acid; quinone compounds such as p-benzoquinone, dichlorobenzoquinone, chloranil, anthraquinone, phenanthroquinone; nitrosobenzene, nitroso-β-naphthol, etc. Well-known radical polymerization inhibitors, such as a nitroso compound, are mentioned, These can be used individually or in combination of 2 or more types.

  The aqueous fatty acid-modified acrylic resin has, for example, a mixture of all polymerizable unsaturated monomers including the fatty acid-modified polymerizable unsaturated monomer obtained as described above, and an average particle diameter of 500 nm in an aqueous medium together with an emulsifier, if necessary. Hereinafter, for example, the dispersion is made so that the average particle diameter is within a range of 50 to 500 nm, particularly 75 to 400 nm, more particularly 100 to 250 nm, and then a monomer emulsion is prepared, followed by polymerization by adding a polymerization initiator. can do.

  As the emulsifier, anionic emulsifiers and nonionic emulsifiers are suitable. Examples of the anionic emulsifiers include sodium salts and ammonium salts such as alkyl sulfonic acids, alkyl benzene sulfonic acids, and alkyl phosphoric acids. Examples of the emulsifier include polyoxyethylene oleyl ether, polyoxyethylene stearyl ether, polyoxyethylene lauryl ether, polyoxyethylene tridecyl ether, polyoxyethylene phenyl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl Ether, polyoxyethylene monolaurate, polyoxyethylene monostearate, polyoxyethylene monooleate, sorbitan monolaurate, sorbitan monostearate Rate, sorbitan trioleate, polyoxyethylene sorbitan monolaurate, and the like.

  Also, a polyoxyalkylene group-containing anionic emulsifier having an anionic group and a polyoxyalkylene group such as a polyoxyethylene group or a polyoxypropylene group in one molecule, or the anionic group and polymerizable unsaturated in one molecule Reactive anionic emulsifiers having groups may be used.

  The emulsifier can be used in the range of 0.1 to 15% by mass, preferably 0.5 to 12% by mass, based on the total amount of all monomers used.

  The polymerization initiator may be either oil-soluble or water-soluble, and examples of the oil-soluble polymerization initiator include benzoyl peroxide, octanoyl peroxide, lauroyl peroxide, stearoyl peroxide. Organic peroxides such as oxides; azo compounds such as azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile); and water-soluble initiators such as cumene hydroperoxide , Organic peroxides such as tert-butyl peroxide, tert-butyl peroxylaurate, tert-butyl peroxyisopropyl carbonate, tert-butyl peroxyacetate, diisopropylbenzene hydroperoxide; azobis (2-methylpropiononitrile) Azo (2-methylbutyronitrile), 4,4′-azobis (4-cyanobutanoic acid), dimethylazobis (2-methylpropionate), 2,2′-azobis [N- (2-carboxycyethyl) ) -2-Methylpropionamidine] hydrate, azobis [2-methyl-N- (2-hydroxyethyl) -propionamide], azobis {2-methyl-N- [2- (1-hydroxybutyl)]-propion Azo compounds such as amide}; persulfates such as potassium persulfate, ammonium persulfate, and sodium persulfate. These can be used alone or in combination of two or more. Further, if necessary, a reducing agent such as sugar, sodium formaldehyde sulfoxylate, or iron complex may be used in combination with the polymerization initiator to form a redox polymerization system.

  The aqueous fatty acid-modified acrylic resin has, for example, a fatty acid-modified polymerizable unsaturated monomer obtained as described above, an acid group-containing polymerizable unsaturated monomer (c), and an alkyl group having 4 or more carbon atoms. The copolymer obtained by copolymerizing the polymerizable unsaturated monomer (d) and other polymerizable unsaturated monomer (e) by solution polymerization in the presence of a polymerization initiator in an organic solvent according to a usual method. It can be produced by a method of neutralizing a polymer with a neutralizing agent to make it water-soluble or water-dispersed, a method of dispersing it in an aqueous medium by a disperser having high energy shearing capability, It can also be produced by a method of seed emulsion polymerization of the above-mentioned fully polymerizable unsaturated monomer in the presence of an emulsifier. Furthermore, for the purpose of adjusting the weight average molecular weight of the obtained copolymer, polymerization may be performed in the presence of a chain transfer agent.

  In this case, the proportion of each monomer used is generally 0.8 to 60% by mass, preferably 4.5 to 55.5% by mass, particularly 4.5 to 55.5% by mass, based on the total amount of monomers. Preferably 10.5-49.5% by weight; monomer (c) 0.1-5% by weight, preferably 0.3-4.5% by weight, particularly preferably 0.5-4.0% by weight; The monomer (d) is 20 to 95% by mass, preferably 25 to 85% by mass, particularly preferably 30 to 75% by mass; the monomer (e) is 4.1 to 79.1% by mass, preferably 10.2 to 70%. .2% by mass, particularly preferably in the range of 14 to 69% by mass.

The polymerizable unsaturated monomer (d) having an alkyl group having 4 or more carbon atoms is at least a part thereof as described above from the viewpoint of the water resistance of the formed coating film and the production stability of the aqueous fatty acid-modified acrylic resin. It is desirable to contain a polymerizable unsaturated monomer having a linear or branched hydrocarbon group having 6 or more carbon atoms. Examples of the polymerizable unsaturated monomer having a linear or branched hydrocarbon group having 6 or more carbon atoms include n-hexyl (meth) acrylate, octyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate. , nonyl (meth) acrylate, tridecyl (meth) acrylate, C _18, such as lauryl (meth) acrylate, stearyl (meth) acrylate and "isostearyl acrylate" (trade name, manufactured by Osaka organic chemical Industry) _- alkyl (meth) acrylate These may be used alone or in combination of two or more. The polymerizable unsaturated monomer having an alkyl group having 6 or more carbon atoms is 1 to 30% by mass based on the total amount of components (a), (b), (c), (d) and (e). , Preferably 3 to 27% by mass, more preferably 5 to 24% by mass.

  The other polymerizable unsaturated monomer (e) preferably contains a carbonyl group-containing polymerizable unsaturated monomer as a copolymerization component as at least a part thereof. Examples of the carbonyl group-containing polymerizable unsaturated monomer include acrolein, diacetone acrylamide, diacetone methacrylamide, acetoacetoxyethyl methacrylate, formylstyrol, and vinyl alkyl ketone having 4 to 7 carbon atoms (for example, vinyl methyl ketone). , Vinyl ethyl ketone, vinyl butyl ketone, etc.), and the like. These can be used alone or in combination of two or more.

  As other polymerizable unsaturated monomer (e), by using a monomer comprising a carbonyl group-containing polymerizable unsaturated monomer, it can be used in combination with a hydrazine derivative described later to oxidatively cure by the fatty acid (a) component. In addition, auxiliary crosslinking between the carbonyl group and the hydrazine derivative can be promoted, the gas barrier properties of the coating film can be further improved, and a coating material having excellent coating properties such as weather resistance and water resistance can be obtained. Can be obtained. At this time, semi-drying oil fatty acid / and / or non-drying oil fatty acid having low oxidative curability can also be used as the fatty acid (a).

  Such a carbonyl group-containing polymerizable unsaturated monomer is 0.5 to 35% by mass, preferably 1 based on the total amount of components (a), (b), (c), (d) and (e). It is suitable to use within the range of -30 mass%, more preferably 2-20 mass%.

  The other polymerizable unsaturated monomer (e) desirably contains a vinyl aromatic compound as at least a part thereof. Thereby, the copolymerizability between monomers can be improved, and water resistance can be imparted to the resulting fatty acid-modified acrylic resin. Such vinyl aromatic compounds are 1 to 50% by weight, preferably 5 to 45% by weight, based on the total amount of components (a), (b), (c), (d) and (e). It is preferable to use within a range of 12 to 35% by mass.

  The aqueous fatty acid-modified acrylic resin (A1) generally has a weight average molecular weight in the range of 10,000 to 500,000, particularly 30,000 to 200,000. When the weight average molecular weight of the resin is less than 10,000, the weather resistance and water resistance of the finally obtained coating film may be lowered. On the contrary, when it exceeds 500,000, the film forming property of the resin particles is lowered. In addition, the barrier properties of the coating film with water-based paint may be reduced. Here, the weight average molecular weight is a value obtained by converting the molecular weight measured by gel permeation chromatography based on the molecular weight of polystyrene using tetrahydrofuran as a solvent. Columns used in the gel permeation chromatography are “TSKgel G-4000H × L”, “TSKgel G-3000H × L”, “TSKgel G-2500H × L”, “TSKgel G-2000H × L” (all Tosoh Corporation).

  In the present invention, when the above-mentioned aqueous fatty acid-modified acrylic resin is used, it is desirable to further contain a hydrazine derivative. Specific examples of the derivatives include saturated carboxylic acid dihydrazides having 2 to 18 carbon atoms such as oxalic acid dihydrazide, malonic acid dihydrazide, glutaric acid dihydrazide, succinic acid dihydrazide, adipic acid dihydrazide, sebacic acid dihydrazide, and the like. Monoolefinic unsaturated dicarboxylic acid dihydrazide such as maleic acid dihydrazide, fumaric acid dihydrazide, itaconic acid dihydrazide; phthalic acid dihydrazide, terephthalic acid dihydrazide or isophthalic acid dihydrazide, pyromellitic acid dihydrazide, trihydrazide or tetrahydrazide; Citric acid trihydrazide, 1,2,4-benzenetrihydrazide, ethylenediaminetetraacetic acid tetrahydrazide, 1,4,5,8-naphthoic acid tetrahydride A polyhydrazide obtained by reacting a low polymer having a carboxylic acid lower alkyl ester group with hydrazine or a hydrazine hydrate (hydrazine hydride); a compound having a hydrazide group such as dihydrazide carbonate; a bissemicarbazide; hexamethylene diisocyanate or isophorone A polyfunctional semicarbazide obtained by excessively reacting a diisocyanate such as diisocyanate and a polyisocyanate compound derived therefrom with N, N-substituted hydrazine such as N, N-dimethylhydrazine or the hydrazide exemplified above; The dihydrazide exemplified above is excessively reacted with an isocyanate group in a reaction product of a polyether and an active hydrogen compound containing a hydrophilic group such as polyols or polyethylene glycol monoalkyl ethers. Resulting aqueous polyfunctional semicarbazide; compound having a semicarbazide group, such as a mixture of polyfunctional semicarbazide and aqueous polyfunctional semicarbazide, compounds and the like having a hydrazone group such as bis-acetyl-di hydrazone.

  By including the hydrazine derivative in the aqueous coating composition of the present invention, the formed coating film is useful because it can adsorb and remove harmful substances in the air, such as formaldehyde, and the aqueous fatty acid-modified acrylic resin is carbonyl. When it has a group, it can act as a crosslinking agent for auxiliary crosslinking. The blending amount of the hydrazine derivative is desirably in the range of 0.01 to 10% by mass, particularly 0.1 to 5% by mass, based on the resin solid content of the fatty acid-modified acrylic resin.

  In the present invention, as the aqueous film-forming resin (A), an aqueous epoxy resin (A2) can be suitably used from the viewpoint of the corrosion resistance of the formed film.

  The aqueous epoxy resin (A2) can be obtained, for example, by dispersing the epoxy resin (f) in water using an emulsifier as necessary.

  The epoxy resin (f) is a resin having one or more, preferably two, epoxy groups in the molecule and a weight average molecular weight of 200 or more. For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol A polyphenol such as an A / F type epoxy resin or a novolac type phenol resin is reacted with an epihalohydrin such as epichlorohydrin to introduce a glycidyl group, or a polyphenol is further reacted with this glycidyl group introduction reaction product. Aromatic epoxy resin with increased molecular weight; epoxy resin such as aliphatic epoxy resin and alicyclic epoxy resin; epoxy obtained by copolymerizing epoxy group-containing polymerizable unsaturated monomer and other polymerizable unsaturated monomer Group-containing acrylic copolymer; has epoxy group Li butadiene resin; polyurethane resin having an epoxy group.

  The said epoxy resin can be used individually or in combination of 2 or more types according to the objective, respectively. Particularly suitable epoxy resins include aromatic epoxy resins.

  The epoxy resin (f) is generally an epoxy having a weight average molecular weight in the range of 200 to 6000, in particular 300 to 2000, more particularly 350 to 2000, and generally in the range of 100 to 3000, in particular 150 to 1000, more particularly 175 to 1000. It is preferable to have an equivalent weight.

  The aqueous epoxy resin (A2) is obtained by making the fatty acid-modified epoxy resin (A2-1) obtained by reacting the fatty acid (a) with the epoxy resin (f) aqueous. Also good.

  In the fatty acid-modified epoxy resin (A2-1), the use ratio of the fatty acid (a) and the epoxy resin (f) is such that the equivalent ratio of the carboxyl group of the fatty acid (a) to the epoxy group of the epoxy resin (f) is 0. It is suitable to be in the range of .75: 1 to 1.25: 1, preferably 0.8: 1 to 1.2: 1.

  The method of making the fatty acid-modified epoxy resin (A2-1) aqueous is not particularly limited, but a method of mixing an emulsifier with the fatty acid-modified epoxy resin and dispersing it in an aqueous medium, the fatty acid-modified epoxy resin In the case where has a carboxyl group, a method in which the carboxyl group is neutralized with a basic substance and then dispersed in an aqueous medium can be mentioned.

  The emulsifier can be appropriately selected from those listed in the description of the aqueous fatty acid-modified acrylic resin (A1). As a compounding quantity, 0.1-15 mass% with respect to resin solid content, Preferably it is 0.1-10 mass%, More preferably, the inside of the range of 0.5-5 mass% is suitable.

  The aqueous epoxy resin (A2) makes a resin obtained by reacting a polymerizable unsaturated monomer (g) with a fatty acid-modified epoxy resin obtained by reacting a fatty acid (a) and an epoxy resin (f). It may be obtained by this.

  In the fatty acid-modified epoxy resin before reacting with the polymerizable unsaturated monomer (g), the proportion of the fatty acid (a) and the epoxy resin (f) used is that of the carboxyl group of the fatty acid (a) and the epoxy resin (f). It is suitable that the equivalent ratio with the epoxy group is in the range of 0.5: 1 to 1.3: 1, preferably 0.5: 1 to 1.2: 1.

  The polymerizable unsaturated monomer (g) can be appropriately selected from those exemplified in the description of each polymerizable unsaturated monomer in the aqueous fatty acid-modified acrylic resin (A1).

  The polymerizable unsaturated monomer (g) preferably contains an aromatic vinyl monomer. As the aromatic vinyl monomer, the same ones as described above can be used, and the use ratio thereof is generally 1 to 50% by weight, preferably 4 to 45% by weight, more preferably in the polymerizable unsaturated monomer (g). 12-35 mass% is suitable.

  The polymerizable unsaturated monomer (g) preferably contains a hydroxyl group-containing polymerizable unsaturated monomer. As the hydroxyl group-containing polymerizable unsaturated monomer, the same ones as described above can be used, and the use ratio thereof is 1 to 50% by mass, preferably 1 to 30% in the polymerizable unsaturated monomer (g). It is desirable to be within the range of mass%.

  The reaction between the fatty acid-modified epoxy resin and the polymerizable unsaturated monomer (g) is performed, for example, by mixing these with a polymerization initiator or the like and heating and reacting within a range of about 60 to 150 ° C. for usually about 1 to 10 hours. It can be carried out. In this case, the use ratio of the fatty acid-modified epoxy resin and the polymerizable unsaturated monomer (g) is 10 to 2000 parts by mass of the polymerizable unsaturated monomer (g), preferably 25 to 100 parts by mass of the fatty acid-modified epoxy resin. It is desirable to be in the range of 1000 parts by mass.

  Further, in order to allow the reaction between the fatty acid-modified epoxy resin and the polymerizable unsaturated monomer (g) to proceed efficiently, the fatty acid-modified epoxy resin contains an epoxy group, and the polymerizable unsaturated monomer (g) contains a carboxyl group-containing polymerizable monomer. Each may contain a saturated monomer. Examples of the polymerizable unsaturated monomer having a carboxyl group include (meth) acrylic acid, fumaric acid, itaconic acid, maleic acid, crotonic acid, β-carboxyethyl acrylate and the like. In the polymerizable unsaturated monomer (g), 0.5 to 20% by mass, preferably 1 to 15% by mass is desirable. When the polymerizable unsaturated monomer (g) contains a carboxyl group-containing polymerizable unsaturated monomer, water dispersibility or pigment dispersibility can be improved, which is preferable.

  In the reaction between the fatty acid-modified epoxy resin and the polymerizable unsaturated monomer (g), the order of the grafting reaction by hydrogen abstraction and the esterification reaction by epoxy group / carboxyl group can be appropriately selected, and can be performed simultaneously. It is.

  The method for making the fatty acid-modified epoxy resin modified with the polymerizable unsaturated monomer (g) aqueous is not particularly limited, and is a method in which an emulsifier is mixed with the fatty acid-modified epoxy resin and dispersed in an aqueous medium. In the case where the fatty acid-modified epoxy resin has a carboxyl group, a method in which the carboxyl group is neutralized with a basic substance and then dispersed in an aqueous medium can be mentioned. Moreover, the organic solvent in a system can also be distilled off and removed as needed after making it aqueous.

  In the present invention, when the aqueous epoxy resin (A2) has an epoxy group, an amine-based curing agent can be further used. The amine-based curing agent is preferably a compound having two or more amino groups, and is not particularly limited. However, aliphatic polyamines, aromatic polyamines, heterocyclic polyamines, epoxy adducts thereof, and Mannich modification It is possible to use a modified product of polyamide or polyamide. Even if it is used as it is, it may be subjected to a purification step such as removal of the solvent, if necessary, and may be homogenized by adding water, and if necessary to give better water dispersibility, The aqueous group may be dispersed by neutralizing the amino group with an organic acid such as acetic acid.

  In the present invention, from the viewpoint of corrosion resistance and water resistance of the obtained coating film, and from the point that the volatile organic solvent content (VOC) can be reduced, the aqueous fatty acid-modified resin (A) is modified with the above-mentioned aqueous fatty acid modification. The acrylic resin (A1) and the aqueous epoxy resin (A2) can be used in combination within a resin solid content ratio of 100: 0 to 10:90, preferably 95: 5 to 30:70 (mass ratio).

  In the present invention, as the aqueous film-forming resin (A), an aqueous alkyd resin (A3) can be preferably used from the viewpoint of the anticorrosion and adhesion of the formed film.

  The aqueous alkyd resin (A3) can be obtained, for example, by making an alkyd resin obtained by esterifying a polybasic acid component, a polyhydric alcohol component, and an oil fatty acid into an aqueous solution by a conventionally known method.

  The coating composition of the present invention contains a nitrogen-containing compound (B) represented by the following general formula (1) as an essential component.

[Wherein, R ¹ represents a monovalent organic group having 4 to 22 carbon atoms. R ² represents a hydrocarbon group having 4 to 22 carbon atoms, an acyl group having 4 to 22 carbon atoms, or

(In the formula, R ⁴ represents an alkylene group having 2 to 10 carbon atoms, and n represents an integer of 0 to 100. When n is 2 or more, a plurality of R ⁴ may be the same or different. .) R ³ represents an alkylene group having 2 to ³ carbon atoms. m shows the integer of 2-100. The plurality of R ³ may be the same or different. ].

Examples of the monovalent organic group having 4 to 22 carbon atoms represented by R ¹ include a hydrocarbon group having 4 to 22 carbon atoms and an acyl group having 4 to 22 carbon atoms.

The alkylene group represented by R ³ and R ⁴ may be a linear alkylene group or a branched alkylene group. The alkylene group represented by R ⁴ preferably has 2 to 3 carbon atoms, and more preferably 2 carbon atoms.

  m is preferably an integer of 2 to 50, more preferably an integer of 2 to 25, still more preferably an integer of 2 to 15, and most preferably an integer of 3 to 10. n is preferably an integer of 0 to 50, more preferably an integer of 1 to 25, still more preferably an integer of 2 to 15, and most preferably an integer of 3 to 10.

  The nitrogen-containing compound (B) is not particularly limited as long as it is a nitrogen-containing compound represented by the general formula (1). As the compound (B), for example, nitrogen-containing compounds (B1) to (B4) described below are preferably used.

  The nitrogen-containing compound (B1) is a compound represented by the following general formula (2).

[Wherein R ⁵ represents a hydrocarbon group having 4 to 22 carbon atoms. R ³ and R ⁴ , m and n are the same as described above. ].

R ⁵ is an alkyl group or an alkenyl group having 4 to 22 carbon atoms, preferably 6 to 18 carbon atoms, more preferably 8 to 14 carbon atoms, from the viewpoint of storage stability of the paint or water resistance of the resulting coating film. It is desirable. Among these, it is more preferable that it is a C6-C18, especially C8-C14 alkyl group.

R ³ and R ⁴ are each preferably an alkylene group having 2 to 3 carbon atoms from the viewpoint of the storage stability of the paint and the water resistance of the resulting coating film, and is an alkylene group having 2 carbon atoms (ethylene group). More preferably it is.

  In addition, from the viewpoint of the storage stability of the paint and the water resistance of the resulting coating film, the sum (m + n) of the added mole number of alkylene oxide in the general formula (2) is 2 to 100, but 2 to 50. Preferably, it is 3-30, more preferably 4-20.

  The nitrogen-containing compound (B1) is prepared by, for example, heating a fatty acid or fatty acid ester and ammonia to produce an aliphatic nitrile, reducing this with hydrogen to synthesize an aliphatic amine, and then converting the aliphatic amine and the alkylene oxide. It can manufacture by making it react.

  Specific examples of the fatty acid include, for example, n-pentanoic acid, n-hexanoic acid, n-heptanoic acid, n-octanoic acid, n-nonanoic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, Examples include oleic acid, coconut oil fatty acid, soybean oil fatty acid, beef tallow fatty acid, palm oil fatty acid, palm kernel oil fatty acid, and the like. Examples of the fatty acid ester include methyl ester and ethyl ester of these fatty acids.

  Examples of the alkylene oxide include ethylene oxide, propylene oxide, butylene oxide, and the like. Among these, ethylene oxide and / or propylene oxide are preferable, and ethylene oxide is more preferable. In the reaction of the aliphatic amine and the alkylene oxide, a basic catalyst such as a metal hydroxide such as sodium hydroxide or potassium hydroxide; sodium methylate; It is preferable to use about ~ 5 mol%.

  Further, the adjustment of the sum (m + n) of the added mole number of the alkylene oxide is performed by adjusting the mixing ratio (molar ratio) of the aliphatic amine and the alkylene oxide in the reaction of the aliphatic amine and the alkylene oxide. be able to.

  The nitrogen-containing compound (B2) is a compound represented by the general formula (3).

[Wherein R ⁶ represents a hydrocarbon group having 3 to 21 carbon atoms. R ³ , R ⁴ , m and n are the same as above. However, 1 ≦ m + n ≦ 100. ].

R ⁶ is an alkyl group or an alkenyl group having 3 to 21 carbon atoms, preferably 6 to 18 carbon atoms, more preferably 8 to 14 carbon atoms, from the viewpoint of storage stability of the paint or water resistance of the resulting coating film. It is desirable. Among these, it is more preferable that it is a C6-C18, especially C8-C14 alkyl group.

R ³ and R ⁴ are each preferably an alkylene group having 2 to 3 carbon atoms from the viewpoint of the storage stability of the paint and the water resistance of the resulting coating film, and is an alkylene group having 2 carbon atoms (ethylene group). More preferably it is.

  In addition, from the viewpoint of the storage stability of the paint and the water resistance of the resulting coating film, the sum (m + n) of the added mole number of alkylene oxide in the general formula (3) is 2 to 100, but 2 to 50. Preferably, it is 3-30, more preferably 4-20.

  The nitrogen-containing compound (B2) can be produced, for example, by reacting a fatty acid or fatty acid ester with ammonia to synthesize an aliphatic amide, and reacting the obtained aliphatic amide with an alkylene oxide. Examples of the fatty acid and alkylene oxide include those listed above in the description of (B1).

  In addition, the adjustment of the sum (m + n) of the added mole number of the alkylene oxide is performed by adjusting the mixing ratio (molar ratio) of the aliphatic amide and the alkylene oxide in the reaction of the aliphatic amide and the alkylene oxide. It can be carried out. For example, the sum (m + n) of the average number of added moles of alkylene oxide of the nitrogen-containing compound (B2) obtained by reacting 20 moles of the alkylene oxide with 1 mole of the aliphatic amide is 20.

  The nitrogen-containing compound (B3) is a compound represented by the following general formula (4).

[Wherein, R ⁷ and R ⁸ independently represent a hydrocarbon group having 3 to 21 carbon atoms. R ³ and m are the same as above. ].

R ⁷ and R ⁸ are each an alkyl having 3 to 21 carbon atoms, preferably 6 to 18 carbon atoms, more preferably 8 to 14 carbon atoms, from the viewpoint of storage stability of the paint and water resistance of the resulting coating film. It is preferably a group or an alkenyl group. Among these, it is more preferable that it is a C6-C18, especially C8-C14 alkyl group.

R ³ is preferably an alkylene group (ethylene group) having 2 carbon atoms from the viewpoint of the storage stability of the paint and the water resistance of the resulting coating film.

  In addition, from the viewpoint of the storage stability of the paint and the water resistance of the resulting coating film, the number m of alkylene oxide added in the general formula (4) is 2 to 100, preferably 2 to 50. 3 to 30 is more preferable, and 4 to 20 is still more preferable.

  The nitrogen-containing compound (B3) can be obtained, for example, by reacting a secondary aliphatic amide with an alkylene oxide. Examples of the alkylene oxide include those listed above in the description of (B1).

  The addition mole number m of alkylene oxide can be adjusted by adjusting the mixing ratio (molar ratio) of the aliphatic amide and the alkylene oxide in the addition reaction of alkylene oxide to the aliphatic amide.

  The nitrogen-containing compound (B4) is a compound represented by the following general formula (5).

[Wherein, R ⁹ and R ¹⁰ independently represent a hydrocarbon group having 4 to 22 carbon atoms. R ³ and m are the same as described above. ].
R ⁹ and R ¹⁰ are each an alkyl having 4 to 22 carbon atoms, preferably 6 to 18 carbon atoms, more preferably 8 to 14 carbon atoms, from the viewpoint of storage stability of the paint and water resistance of the resulting coating film. It is preferably a group or an alkenyl group. Among these, it is more preferable that it is a C6-C18, especially C8-C14 alkyl group.

R ³ is preferably an alkylene group (ethylene group) having 2 carbon atoms from the viewpoint of the storage stability of the paint and the water resistance of the resulting coating film.

  In addition, from the viewpoint of storage stability of the paint and water resistance of the resulting coating film, the number m of alkylene oxide added in the general formula (5) is 2 to 100, preferably 2 to 50. 3 to 30 is more preferable, and 4 to 20 is still more preferable.

  The nitrogen-containing compound (B4) can be obtained, for example, by reacting a secondary aliphatic amine with alkylene oxide. Examples of the alkylene oxide include those listed above in the description of (B1).

  The nitrogen-containing compound (B) used in the present invention preferably has a molecular weight of about 100 to 4,000, more preferably about 200 to 2,000, and more preferably about 300 to 1,500. preferable. In addition, the compound (B) preferably has an HLB value of about 8 to 18, more preferably about 10 to 17, and still more preferably about 13 to 16.

The HLB value of the nitrogen-containing compound (B) is a Griffin formula based on mass fraction:
HLB value = 20 × (MH / M)
(Wherein, MH represents the molecular weight of the hydrophilic group in the nitrogen-containing compound (B), and M represents the molecular weight of the nitrogen-containing compound (B)).

  The blending ratio of the nitrogen-containing compound (B) is preferably about 1 to 20 parts by mass with respect to 100 parts by mass of the aqueous film-forming resin (A) from the viewpoint of improving the storage stability of the paint. The amount is more preferably about 20 parts by mass, and still more preferably about 3 to 15 parts by mass.

  In the present invention, as the nitrogen-containing compound (B), the nitrogen-containing compound (B1) is particularly preferable from the viewpoints of storage stability of the paint and water resistance of the formed coating film.

  The coating composition of this invention contains the antirust pigment (C) which does not contain chromium and lead as an essential component.

  As the rust preventive pigment (C), various conventionally known rust preventive pigments can be used without particular limitation as long as they are pollution-free rust preventive pigments not containing chromium and lead. For example, Mg, K, Ca, Ba, At least one metal selected from Zn and Al must be at least one selected from phosphate, phosphite, polyphosphate, molybdate, phosphomolybdate, metaborate and cyanamide salt. Is desirable from the viewpoint of corrosion resistance. Specific examples thereof include, for example, zinc phosphate, calcium phosphate, magnesium phosphate, phosphorus / zinc silicate, calcium phosphite, aluminum phosphite, zinc calcium phosphite, aluminum pyrophosphate, calcium pyrophosphate, dihydrogen tripolyphosphate. Aluminum, zinc polyphosphate, aluminum polyphosphate, aluminum metaphosphate, calcium metaphosphate, zinc molybdate, calcium molybdate, zinc phosphomolybdate, aluminum phosphomolybdate, barium borate, barium metaborate, cyanamide zinc, calcium cyanamide zinc, And hydrates thereof. These may be subjected to various surface treatments.

  In the present invention, as the rust preventive pigment (C), particularly from the viewpoint of corrosion resistance, the electric conductivity of the water extract is 0.05 mS / cm or more, preferably 0.10 mS / cm or more, more preferably 0.15 mS / cm. It is desirable to contain a phosphite of cm or more.

  Here, the electrical conductivity (mS / cm) of the water extract is 5 for each rust preventive pigment according to the method described in JIS K 5101-18: 2004 (Pigment Test Method—Part 18: Electrical Resistivity). In addition to deionized water so as to have a concentration by mass, the water extract after being allowed to stand at 40 ° C. for 5 days is measured.

  The blending ratio of the rust preventive pigment (C) is about 1 to 80 parts by mass with respect to 100 parts by mass of the aqueous film-forming resin (A) from the viewpoint of improving the storage stability of the paint and the corrosion resistance of the formed coating film. It is preferable that it is about 3 to 70 parts by mass, and more preferably about 3 to 60 parts by mass.

  In the present invention, color pigments, extender pigments and the like known in the paint field can be blended as a pigment component as necessary.

  In the present invention, it is possible to improve the pigment dispersion stability and storage stability by dispersing the pigment component containing the rust preventive pigment (C) in the aqueous medium together with the nitrogen-containing compound (B). From the point of view, it is preferable.

  In addition, the aqueous coating composition of the present invention further includes at least one basic compound selected from the group consisting of nitrite, phytate, tannate, and polyamine compound from the viewpoint of suppressing flash rust (point rust). Can be included. Examples of the nitrite include sodium nitrite, calcium nitrite, strontium nitrite, barium nitrite, ammonium nitrite and the like, and examples of the phytate include sodium phytate and potassium phytate, Examples of the tannate include sodium tannate and potassium tannate. Examples of the polyamine compound include N- (2-hydroxyethyl) ethylenediaminetriacetic acid (HEDTA), ethylenediaminetetraacetic acid (EDTA), Diethylenetriaminepentaacetic acid (DTPA), propylenediaminetetraacetic acid (PDTA), iminodiacetic acid, nitrilotriacetic acid (NTA), diethylenetriaminepentamethylenephosphonic acid (DTPMP), and their alkali metal salts, monoalkylamines Polyamine, an interlayer compound formed by intercalating the like in layers phosphate and quaternary ammonium ion such as dihydrogen tripolyphosphate aluminum. These can be used alone or in combination of two or more.

  The blending ratio of the basic compound is 0.05 to 5 parts by mass, preferably 0.1 to 3 parts by mass with respect to 100 parts by mass of the aqueous film-forming resin (A), from the viewpoint of improving flash rust suppression. Within the range of the part is appropriate.

  In addition to the above-mentioned components, the above-mentioned water-based paint composition may contain a pigment dispersant, a surfactant, a curing catalyst, an antifoaming agent, a thickening agent, a film-forming aid, an antiseptic, an antifungal agent, and an anti-freezing agent. Agents, pH adjusters, aldehyde scavengers, layered viscosity minerals, powdered or particulate activated carbon, polyalkylene glycol-modified alkyl silicate and other low-contaminants, ultraviolet absorbers, light stabilizers and other additives alone or It can contain in combination of 2 or more types.

  The water-based paint composition can be applied to the surface of a metal base material such as iron or aluminum or the old paint surface on the metal base material. As the old coating film, an acrylic resin system provided on these base materials, Examples of the coating film include acrylic urethane resin, polyurethane resin, fluororesin, silicon acrylic resin, vinyl acetate resin, epoxy resin, and alkyd resin. It is also possible to apply a known aqueous topcoat material to these coated surfaces after applying the aqueous coating composition of the present invention as an undercoat material.

The aqueous coating composition of the present invention can be applied by a method such as air spray coating, airless spray coating, electrostatic coating, brush coating, roller coating, lysing gun, universal gun, etc., and as a drying method, Any of heat drying, forced drying, and room temperature drying may be used. In this specification, the drying condition of less than 40 ° C. is normal temperature drying, the drying condition of 40 ° C. or more and less than 80 ° C. is forced drying, and the drying condition of 80 ° C. or more is heat drying. As a coating amount of the aqueous coating composition of this invention, it can be in the range of 50-300 g / m < ² >, for example.

  Moreover, in addition to being able to be used as an undercoat material excellent in corrosion resistance, the aqueous coating composition of the present invention can also be used as an overcoat material imparted with weather resistance. Therefore, the water-based coating composition of the present invention can be directly applied to a substrate and can be finished in a single coat that also serves as an undercoat. By making one coat finish, it is possible to shorten the painting process and the painting period. Undercoat film suitable for each substrate [Primer film formed by applying primers such as wash primer and zinc epoxy shop primer to a blasted steel sheet; vinyl tar, oily rust stop, chlorination It can also be applied to a substrate on which an undercoat primer coating formed by applying primer such as rubber or epoxy, or a multi-layer coating formed by sequentially applying primer and primer coating] it can. Furthermore, the base material on which the old coating film is formed can also be painted. In these cases, the coating method is not particularly limited, and the coating can be performed by the same coating method as described above. Further, the drying method is not particularly limited, and the drying can be performed by the same drying method as described above. As a coating amount, it can be in the range of 25-300 micrometers by a film thickness, for example.

  Hereinafter, the present invention will be described in more detail with reference to examples. “Part” and “%” indicate “part by mass” and “% by mass” unless otherwise specified.

Production example 1 of fatty acid-modified monomer
The following components were put into a reaction vessel and reacted at a reaction temperature of 140 ° C. with stirring to obtain a fatty acid-modified monomer (a-1). The reaction between epoxy groups and carboxyl groups was monitored by measuring the amount of residual carboxyl groups. It took about 5 hours to complete the reaction.
Flaxseed oil fatty acid 280 parts Glycidyl methacrylate 142 parts

Production Example 2
A fatty acid-modified monomer (a-2) was obtained in the same manner as in Production Example 1 except that the components to be reacted were changed to the following.
Soybean fatty acid 280 parts Glycidyl methacrylate 142 parts

Production and production example 3 of aqueous resin dispersion
The following components are put in a glass beaker, stirred at 2000 rpm for 15 minutes with a disper to produce a preliminary emulsion, and then this preliminary emulsion is applied at 100 MPa with a high-pressure emulsifier that collides fluids by applying high-pressure energy. By performing the high-pressure treatment, a monomer emulsion having an average particle size of the dispersed particles of 190 nm was obtained.

Monomer emulsion composition Fatty acid-modified monomer (a-1) 30.15 parts Styrene 15 parts Hydroxyethyl methacrylate 4.5 parts i-butyl methacrylate 20.35 parts t-butyl methacrylate 20 parts 2-ethylhexyl acrylate 8 parts Methacrylic acid 2 parts "Newcol 707SF" (Note 1) 10 parts deionized water 85 parts

  The monomer emulsion was then transferred to a flask and diluted with deionized water to a solids concentration of 45%. Thereafter, the temperature was raised to 85 ° C., and an initiator aqueous solution in which 1.0 part of ammonium persulfate was dissolved in 15 parts of deionized water was added to the flask, and stirred for 3 hours while maintaining the temperature. Thereafter, an initiator aqueous solution in which 0.3 part of ammonium persulfate was dissolved in 2.7 parts of deionized water was added to the flask, stirred for 1 hour while maintaining the temperature, cooled to 40 ° C., and then adjusted to pH with dimethylaminoethanol. Was adjusted to 8.0 to obtain an aqueous resin dispersion (I-1) having a solid content concentration of 40% and an average particle size of the dispersed resin of 165 nm.

  (Note 1) “Newcol 707SF”: trade name, manufactured by Nippon Emulsifier Co., Ltd., an anionic emulsifier having a polyoxyethylene chain, active ingredient 30%

Production Example 4
An aqueous resin dispersion (I-2) was obtained in the same manner as in Production Example 3 except that the fatty acid-modified monomer (a-1) was changed to the fatty acid-modified monomer (a-2) in the composition of the monomer emulsion. .

Manufacture of water-based paint composition (Part 1)
Examples 1-31 and Comparative Examples 1-5
Each component of clean water, a dispersant, a nitrogen-containing compound and a pigment was sequentially charged into the container as shown in Table 1, and stirring was continued with a disper for 30 minutes until each pigment paste was obtained. Thereafter, an aqueous film-forming resin component such as an aqueous resin dispersion and an additive were added to each pigment paste to obtain each aqueous coating composition. Subsequently, each water-based coating composition was subjected to the following evaluation tests (* 1) to (* 3) and evaluated. The results are also shown in Table 1.

In Table 1, (Note 2) to (Note 25) are as follows.
(Note 2) “BYK-190”: Trade name, manufactured by BYK Chemie, Dispersant (Note 3) “BLAUNON L220”: Trade name, manufactured by Aoki Yushi Kogyo Co., Ltd., polyoxyethylene laurylamine, represented by the general formula (2) , R ⁵ is a lauryl group, R ³ and R ⁴ are ethylene groups, and m + n = 20. The HLB value is 16.2.
(Note 4) “BLAUNON L230”: trade name, manufactured by Aoki Yushi Kogyo Co., Ltd., polyoxyethylene laurylamine, in the above general formula (2), R ⁵ is a lauryl group, and R ³ and R ⁴ are ethylene groups , M + n = 30. The HLB value is 17.5
(Note 5) “BLAUNON L210”: trade name, manufactured by Aoki Yushi Kogyo Co., Ltd., polyoxyethylene laurylamine, in the above general formula (2), R ⁵ is a lauryl group, and R ³ and R ⁴ are ethylene groups , M + n = 10. The HLB value is 13.6.
(Note 6) “Esomine S25”: trade name, manufactured by Lion Akzo, the above general formula (2), R ⁵ is a soybean oil fatty acid residue, R ³ and R ⁴ are ethylene groups, and m + n = 15 A compound that is The HLB value is 14.2.
(Note 7) “Esomine C25”: trade name, manufactured by Lion Akzo, in the above general formula (2), R ⁵ is a coconut oil fatty acid residue, R ³ and R ⁴ are ethylene groups, and m + n = 15 A compound that is The HLB value is 15.4.
(Note 8) “Esomine O20”: a trade name, manufactured by Lion Akzo, general formula (2), wherein R ⁵ is an oleyl group, R ³ and R ⁴ are ethylene groups, and m + n = 10 . The HLB value is 12.5

(Note 9) “Titanium white JR-605”: trade name, manufactured by Teika, Titanium white (Note 10) “EXPERT NP-1007”: trade name, manufactured by Toho Pigment, zinc phosphate / calcium phosphite, water extract Electrical conductivity of 0.663 mS / cm
(Note 11) “EXPERT NP-1020C”: trade name, manufactured by Toho Pigment Co., Ltd., calcium phosphite, electric conductivity of water extract 0.700 mS / cm
(Note 12) “EXPERT NP-1102”: trade name, manufactured by Toho Pigment Co., Ltd., aluminum phosphite, electric conductivity of water extract 0.720 mS / cm
(Note 13) “EXPERT NP-1530”: trade name, manufactured by Toho Pigment Co., Ltd., zinc phosphite, electric conductivity of water extract 3.000 mS / cm
(Note 14) “EXPERT NP-1600”: trade name, manufactured by Toho Pigment Co., Ltd., zinc phosphite, electric conductivity of water extract 0.071 mS / cm
(Note 15) "EXPERT NP-1802": trade name, manufactured by Toho Pigment Co., Ltd., magnesium phosphite, electric conductivity of water extract 0.707 mS / cm
(Note 16) “EXPERT NP-530”: trade name, manufactured by Toho Pigment Co., Ltd., zinc phosphate, electrical conductivity of aqueous extract 0.019 mS / cm
(Note 17) “K-White140W”: trade name, manufactured by Teika, aluminum tripolyphosphate / zinc oxide, electric conductivity of water extract 0.447 mS / cm

(Note 18) “MODEPICS 301”: trade name, manufactured by Arakawa Chemical Industries, epoxy ester emulsion, solid content concentration of 33% by mass
(Note 19) “ADEKA RESIN EM101-50”: trade name, manufactured by ADEKA, epoxy emulsion, solid concentration 50% by mass
(Note 20) “Epilink 360”: trade name, manufactured by Air Products, polyamine-based curing agent, solid content concentration 50 mass%
(Note 21) “Worlee E330W”: trade name, manufactured by WORLEE, alkyd resin emulsion, solid concentration 42% by mass
(Note 22) "DICnate 1000W": manufactured by Dainippon Ink, trade name, metal dryer, Co content 3.6%
(Note 23) “TEXANOL”: manufactured by Eastman Chemical Co., Ltd., trade name, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, film-forming aid (Note 24) “Adecanol UH-420” : Brand name, manufactured by Adeka, thickener (Note 25) "SN deformer 380": Brand name, manufactured by San Nopco, defoaming agent

Manufacture of water-based paint composition (Part 2)
Examples 32-51 and Comparative Examples 6 and 7
As shown in Table 2, each component of clean water, a dispersant, a nitrogen-containing compound and a pigment was sequentially charged into the container, and stirring was continued for 30 minutes with a disper to obtain each pigment paste. Thereafter, an aqueous film-forming resin component such as an aqueous resin dispersion and an additive were added to each pigment paste to obtain each aqueous coating composition. Subsequently, each water-based coating composition was subjected to the following evaluation tests (* 1) to (* 5) and evaluated. The results are also shown in Table 2.

Evaluation Test Method (* 1) Storage Stability Each aqueous coating composition obtained in Examples and Comparative Examples was put in 1 kg of an inner surface coated can having a capacity of 1 L, sealed with nitrogen, and stored at 40 ° C. for 2 weeks. Then, it returned to room temperature, the state in a container was observed visually, and the following reference | standard evaluated.
○: The initial state is not changed, and Δ: Pigment sedimentation or shading occurs x: Gelation

(* 2) Water resistance Each aqueous coating composition obtained in Examples and Comparative Examples was coated on an untreated mild steel plate with an applicator so that the dry film thickness was 40 μm, and was cured at 25 ° C. for 10 days to form a film. A test plate was prepared. Each test plate obtained was immersed in clean water for 3 days, and then pulled up to evaluate the degree of rust and swelling generated on each test plate according to the following criteria.
○: No abnormalities such as rust and blisters △: Rust and bulges are slightly generated ×: Rust and bulges are remarkably generated

(* 3) Corrosion resistance After coating each water-based paint composition obtained in Examples and Comparative Examples on an untreated mild steel plate with an applicator so as to have a dry film thickness of 40 μm, and curing at 25 ° C. for 10 days, A test plate was prepared by cross-cutting the coated surface with a cutter. Each obtained test plate was exposed to salt spray for 120 hours according to JIS Z2371 salt spray test. Thereafter, the degree of rust and swelling generated on each test plate was evaluated according to the following criteria.
○: The rust width of the cut part is less than 1 mm, and there is no abnormality such as rust and swelling in the general part. Δ: The rust width of the cut part is 1 to 3 mm, but a little rust and swelling occur in the general part. The rust width of the part exceeds 3mm, and rust and blisters occur remarkably

(* 4) Gloss Each water-based paint composition obtained in Examples and Comparative Examples was coated on an untreated mild steel plate with an applicator so that the dry film thickness was 40 μm, and cured at 25 ° C. for 10 days to form a film. And used as a test plate. The 60 ° gloss of the obtained test plate was measured.
○: 60 ° gloss 50 or more ×: 60 ° gloss less than 50

(* 5) Gloss retention rate The test plate prepared in the above gloss evaluation test was subjected to an accelerated weathering test for 480 hours using a sunshine carbon arc lamp type tester (manufactured by Suga Test Instruments Co., Ltd.), and then 60 before and after the test. The gloss retention (%) was calculated from the gloss by the following formula.

Gloss retention = (60 ° gloss value after test / 60 ° gloss value before test) × 100
○: Gloss retention 60% or more ×: Gloss retention less than 60%

Claims (4)

(A) 100 parts by mass of an aqueous film-forming resin (solid ) containing an aqueous fatty acid-modified acrylic resin (A1) and an aqueous epoxy resin (A2) in a resin solid content ratio of 95: 5 to 30:70 (mass ratio) For)
(B) General formula (1)

[Wherein, R ¹ represents a monovalent organic group having 4 to 22 carbon atoms. R ² represents a hydrocarbon group having 4 to 22 carbon atoms, an acyl group having 4 to 22 carbon atoms, or

(In the formula, R ⁴ represents an alkylene group having 2 to 10 carbon atoms, and n represents an integer of 0 to 100. When n is 2 or more, a plurality of R ⁴ may be the same or different. .) R ³ represents an alkylene group having 2 to ³ carbon atoms. m shows the integer of 2-100. The plurality of R ³ may be the same or different. 1 to 20 parts by mass (solid content) of the nitrogen-containing compound represented by the formula (1), and (C) 1 to 80 parts by mass of a rust preventive pigment not containing chromium and lead , and the rust preventive pigment (C) A phosphite of at least one metal selected from Mg, K, Ca, Ba, Zn and Al , characterized in that it contains a phosphite having an electric conductivity of an aqueous extract of 0.05 mS / cm or more. A water-based coating composition. The nitrogen-containing compound (B) is represented by the general formula (2)

[Wherein R ⁵ represents a hydrocarbon group having 4 to 22 carbon atoms. R ³ and R ⁴ , m and n are the same as described above. The water-based coating composition according to claim 1, which is a nitrogen-containing compound (B1) represented by the formula: The aqueous coating composition according to claim 1 or 2 , wherein the nitrogen-containing compound (B) has an HLB value in the range of 8-18. A coating method comprising applying the aqueous coating composition according to any one of claims 1 to 3 to a metal substrate surface or an old painted surface on a metal substrate.