JP2000239569A - Water-based coating composition and article coated with the composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water-based coating material capable of forming a coating film having excellent anti-corrosion property on an aluminum-plated steel plate without using an anticorrosive agent containing harmful heavy metals. SOLUTION: The objective composition contains (A) 50-100 pts.wt. of at least one kind of water-based resin selected from water-based alkyd resin and water-based epoxy ester resin, (B) 0-50 pts.wt. of a water-based acrylic resin and (C) 0-30 pts.wt. of a water-based melamine resin wherein these resins constitute 100 pts.wt. of a film-forming resin component, and further contains (D) 5-50 pts.wt. of fine particles of a calcium ion-exchanged amorphous silica, (E) 5-50 pts.wt. of a phosphate-based anticorrosive pigment modified with a magnesium compound and (F) 0.1-10 pts.wt. of a triazole compound. A coated material having an aluminum-plated steel plate as the substrate can be produced by forming the coating film with the composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aqueous coating composition which does not contain harmful heavy metals and has excellent anticorrosion properties, and a coated article based on an aluminum-plated steel sheet coated with the coating composition.

[0002]

2. Description of the Related Art
Lead / tin alloy plated steel sheet (turn sheet) is used as a material for gasoline tanks, but from the viewpoint of global environmental conservation such as not using harmful lead, the material was changed from turn sheet to aluminum plated steel sheet. Considerations are being made.

[0003] Paints currently used for turn sheets, both solvent-based paints and water-soluble paints, are applied to an aluminum-plated steel sheet with the same composition, and as a result, the anti-corrosion property is higher than when applied to a turn sheet. There was a problem of being extremely inferior. As a measure to solve this problem, it is conceivable to use a large amount of harmful heavy metals such as chromium-based rust preventives and lead-based rust preventives. It does not fit the purpose.
Further, the solvent type paint is not preferable from the viewpoint of regulation of CO ₂ gas emission for preventing global warming.

Accordingly, the present inventors have conducted intensive studies to obtain a water-based paint capable of forming a coating film having excellent anticorrosion properties on an aluminum-plated steel sheet without using a rust inhibitor containing harmful heavy metals. As a result, the present inventors have found that a desired paint can be obtained by combining a specific aqueous resin with calcium ion-exchanged silica fine particles, a phosphate-based rust preventive pigment modified with a magnesium compound, and a triazole compound. Was completed.

[0005]

That is, the present invention provides:
(A) 50 to 100 parts by weight of at least one aqueous resin selected from an aqueous alkyd resin and an aqueous epoxy ester resin; (B) 0 to 50 parts by weight of an aqueous acrylic resin; and (C) 0 to 30 parts by weight of an aqueous melamine resin. (D) calcium ion-exchanged amorphous silica fine particles 5 to 50 parts by weight based on 100 parts by weight of the total amount of the film-forming resin component
An aqueous coating composition comprising: (E) 5 to 50 parts by weight of a phosphate-based rust preventive pigment modified with a magnesium compound and (F) 0.1 to 10 parts by weight of a triazole compound. To provide.

[0006] The present invention also provides an aluminum-plated steel sheet comprising a water-based coating composition formed on an aluminum-plated steel sheet substrate which may be subjected to a chemical conversion treatment and / or an organic coating treatment. To provide a coated article.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Each component of the coating composition of the present invention will be described in detail below.

Aqueous resin (A) The aqueous resin as the component (A) of the composition of the present invention is at least one resin selected from aqueous alkyd resins and aqueous epoxy ester resins. In the present invention, "aqueous"
Means water-soluble or water-dispersible.

The aqueous alkyd resin comprises a polybasic acid component,
The resin is not particularly limited as long as it is a resin obtained by esterifying a polyhydric alcohol component and an oil fatty acid, and is water-based and has a film-forming ability.

The polybasic acid component is selected from, for example, phthalic anhydride, isophthalic acid, terephthalic acid, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, succinic acid, fumaric acid, adipic acid, sebacic acid, maleic anhydride and the like. One or more dibasic acids and lower alkyl esterified products of these acids are mainly used, and if necessary, tribasic or higher polybasic acids such as trimellitic anhydride, methylcyclohexentricarboxylic acid, and pyromellitic anhydride. Are used together. As the acid component, a monobasic acid such as benzoic acid, crotonic acid, pt-butylbenzoic acid, and the like can be used in combination for the purpose of adjusting the molecular weight.

Examples of the polyhydric alcohol component include ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, 3-methylpentanediol, 1,4-hexanediol, and 1,6-hexanediol. A dihydric alcohol such as glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol can be used as needed. These polyhydric alcohols can be used alone or in combination of two or more. Further, a part of the acid component and the alcohol component may be dimethylolpropionic acid, oxypivalic acid, paraoxybenzoic acid, etc .; lower alkyl esters of these acids;
-It can be replaced with an oxyacid component such as lactones such as caprolactone.

Examples of the oil fatty acids include coconut oil fatty acids, soybean oil fatty acids, linseed oil fatty acids, safflower oil fatty acids, tall oil fatty acids, dehydrated castor oil fatty acids, and tung oil fatty acids. Oil length of alkyd resin is 3
0% or less, especially about 5 to 20% is preferable.

The esterification reaction (including the transesterification reaction) of these components can be carried out by a method known per se.

An epoxy-modified alkyd resin obtained by partially esterifying an epoxy compound using an epoxy compound as a part of the alcohol component, and a vinyl-modified alkyd resin obtained by graft-polymerizing a vinyl monomer such as styrene onto an alkyd resin are also provided by the present invention. Of alkyd resins.

In order to make the alkyd resin aqueous, for example, a method in which the alkyd resin has a high acid value and is neutralized with a basic compound such as an amine compound to make the alkyd resin aqueous, a polyoxyethylene group is contained in the alkyd resin. Introduce hydrophilic groups such as
A method of self-emulsifying in water by the function of the hydrophilic group, a method of forcibly stirring an alkyd resin in water in the presence of an emulsifier, and a method of dispersing the alkyd resin in water, and a method of using these in combination can be exemplified.

Although the molecular weight of the aqueous alkyd resin is not particularly limited, it is usually a number average molecular weight of 2,0.
Preferably, it is in the range of from 00 to 10,000.

Commercially available aqueous alkyd resins include, for example, Residrol VWA5377 and VWA5499.
AX246W and AX906W (both are VI
ANOVA (Vianova), Watersol BC
-3010, S-118, and S-346 (all, manufactured by Dainippon Ink and Chemicals, Inc.).

The aqueous epoxy ester resin which can be used as the component (A) is a resin in which an epoxy resin and an acid component are ester-bonded and are stably dissolved or dispersed in water.

As the aqueous epoxy ester resin, for example, a carboxyl group-excess partial reactant obtained by reacting a carboxyl group-containing polymer such as an acrylic resin with an epoxy resin is dispersed in an aqueous medium in the presence of ammonia or an amine. (For example, Japanese Patent Application Laid-Open No. 54-75)
460, JP-A-55-3481, and JP-A-5-3481.
JP-A-5-3482), an adduct having a polymerizable unsaturated double bond in a molecule obtained by partially reacting an epoxy resin with a carboxyl group-containing polymerizable unsaturated compound such as (meth) acrylic acid, A polymer obtained by polymerizing a monomer mixture containing (meth) acrylic acid, neutralizing a carboxyl group of the polymer of the monomer mixture with a basic compound, and dispersing the polymer in an aqueous medium (for example, JP-A-57-105418). JP-A-58-198513), a resin obtained by reacting an epoxy resin with a dibasic acid such as succinic acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, dodecane diacid, and hexahydrophthalic acid. And the like, which are obtained by neutralizing the carboxyl group with a basic compound and dispersing the same in an aqueous medium.

Examples of the epoxy resin include a bisphenol type epoxy resin and a novolak type epoxy resin. Bisphenol type epoxy resin is
For example, a resin obtained by condensing epichlorohydrin and bisphenol to a high molecular weight in the presence of a catalyst such as an alkali catalyst, if necessary, epichlorohydrin and bisphenol, if necessary, in the presence of a catalyst such as an alkali catalyst, condensation This may be a low-molecular-weight epoxy resin, and any resin obtained by subjecting the low-molecular-weight epoxy resin to a bisphenol to undergo a polyaddition reaction may be used.

As the bisphenol, bis (4-
Hydroxyphenyl) methane [bisphenol F],
1,1-bis (4-hydroxyphenyl) ethane, 2,
2-bis (4-hydroxyphenyl) propane [bisphenol A], 2,2-bis (4-hydroxyphenyl) butane [bisphenol B], bis (4-hydroxyphenyl) -1,1-isobutane, bis (4- Hydroxy-tert-butyl-phenyl) -2,2-propane, p- (4-hydroxyphenyl) phenol, oxybis (4-hydroxyphenyl), sulfonylbis (4-hydroxyphenyl), 4,4′-dihydroxybenzophenone, Bis (2-hydroxynaphthyl) methane and the like can be mentioned, and among them, bisphenol A and bisphenol F are preferably used. The above bisphenols can be used alone or as a mixture of two or more.

Commercially available bisphenol type epoxy resins include, for example, Epicoat 828 (epoxy equivalent: about 190, number average molecular weight: about 350) and Epicoat 812 (epoxy equivalent: about 150, manufactured by Yuka Shell Epoxy Co., Ltd.).
Epicoat 815 (epoxy equivalent: about 180, number average molecular weight: about 350), Epicoat 8
20 (epoxy equivalent about 190, number average molecular weight about 35
0), Epicoat 834 (epoxy equivalent: about 250, number average molecular weight: about 470), Epicoat 1001 (epoxy equivalent: about 490, number average molecular weight: about 900), Epicoat 10
04 (epoxy equivalent about 950, number average molecular weight about 140
0), Epicoat 1007 (epoxy equivalent about 1,70
0, number average molecular weight about 2,900), Epicoat 1009
(Epoxy equivalent about 3,500, number average molecular weight about 3,75
0), Epicoat 1010 (epoxy equivalent of about 4,50
0, number average molecular weight of about 5,500); Araldite AER6099 (epoxy equivalent of about 3,500;
A number average molecular weight of about 3,800); and Epomic R-309 (epoxy equivalent of about 3,50) manufactured by Mitsui Chemicals, Inc.
0, a number average molecular weight of about 3,800).

Examples of the novolak type epoxy resin usable as the epoxy resin include various novolak types such as phenol novolak type epoxy resin, cresol novolak type epoxy resin, and phenol glyoxal type epoxy resin having a large number of epoxy groups in a molecule. Type epoxy resin.

Aqueous Acrylic Resin (B) In the composition of the present invention, the aqueous acrylic resin (B) is a water-soluble or water-dispersible acrylic resin, and a carboxyl group-containing acrylic resin polymerized in an organic solvent. Examples thereof include a water-soluble or water-dispersible acrylic resin neutralized and made aqueous with a basic compound such as an amine compound, and an acrylic resin aqueous dispersion obtained by emulsion polymerization. The aqueous acrylic resin (B) is a resin that is blended into the composition of the present invention as needed.

The aqueous acrylic resin (B) is a copolymer resin containing a carboxyl group-containing polymerizable unsaturated monomer and another polymerizable unsaturated monomer as monomer components.

Examples of the carboxyl group-containing polymerizable unsaturated monomer include one or a mixture of two or more of acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, and fumaric acid.

The other polymerizable unsaturated monomer may be any monomer that can be copolymerized with the above-mentioned carboxyl group-containing polymerizable unsaturated monomer, and can be appropriately selected and used according to the required performance. For example, aromatic vinyl monomers such as styrene, vinyltoluene, 2-methylstyrene, t-butylstyrene, and chlorostyrene; methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, and n-acrylate , I- or t-butyl, hexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate,
Decyl acrylate, lauryl acrylate, cyclohexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-, i- or t-butyl methacrylate, hexyl methacrylate, 2-methacrylate Ethylhexyl, octyl methacrylate, decyl methacrylate, lauryl methacrylate, cyclohexyl methacrylate and the like, alkyl or cycloalkyl esters of acrylic acid or methacrylic acid having 1 to 18 carbon atoms; 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate,
C2 of acrylic acid or methacrylic acid such as 3-hydroxypropyl acrylate, hydroxybutyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 3-hydroxypropyl methacrylate, and hydroxybutyl methacrylate
-C8 hydroxyalkyl ester; N-methylolacrylamide, N-butoxymethylacrylamide, N
One or a mixture of two or more of N-substituted acrylamide-based or N-substituted methacrylamide-based monomers such as -methoxymethylacrylamide, N-methylolmethacrylamide, and N-butoxymethylmethacrylamide.

A copolymer of the above monomer components can be obtained by a polymerization method known per se, such as solution polymerization or emulsion polymerization. The copolymer obtained by solution polymerization can be made aqueous by neutralizing with a basic compound.

Although the molecular weight of the water-based acrylic resin (B) is not particularly limited, it is usually a number average molecular weight of 5,0.
It is preferably in the range of 100 to 100,000.

Aqueous Melamine Resin (C) The aqueous melamine resin (C) functions as a curing agent that reacts with the aqueous resin (A) and the above-mentioned aqueous acrylic resin (B), which is blended as required. Of a methylolated amino resin obtained by the reaction of a phenol with an aldehyde and an etherified amino resin obtained by etherifying a methylolated amino resin with an appropriate alcohol, those having water solubility or water dispersibility. As the aldehyde used in the above reaction, formaldehyde,
Examples include paraformaldehyde, acetaldehyde, and benzaldehyde. Examples of the alcohol used for the etherification include methyl alcohol, ethyl alcohol, n-propyl alcohol, i-propyl alcohol, n-butyl alcohol, i-butyl alcohol, and the like, and methyl alcohol is preferably used. You.

Specific examples of the aqueous melamine resin (C) include, for example, Cymel 300, 303, 325, and 3
27, 350, 370 [all, manufactured by Mitsui Cytec Co., Ltd.], Nicaraq MS15, MS17, MX430, MX650 [all, manufactured by Sanwa Chemical Co., Ltd.], Sumimar M-55 [ Sumitomo Chemical Co., Ltd.
Melamine resins such as Resin 740, 741 [all and Monsanto Co.]; Cymel 202, 235, 238, 254, 27
2, 1130 [all, Mitsui Cytec Co., Ltd.
Melamine resins mixed with methyl ether and butyl ether, such as Nikalac MX485 and MX487 (all of which are manufactured by Sanwa Chemical Co., Ltd.) and Resimin 755 (manufactured by Monsanto Co., Ltd.). These melamine resins can be used alone or as a mixture of two or more.

In the composition of the present invention, the mixing ratio of the aqueous resin (A), the aqueous acrylic resin (B) and the aqueous melamine resin (C) is the sum of (A), (B) and (C). The aqueous resin (A) is 50 to 1 in 100 parts by weight of the solid content.
00 parts by weight, preferably 60 to 90 parts by weight, the aqueous acrylic resin (B) is 0 to 50 parts by weight, preferably 0 to 40 parts by weight, and the aqueous melamine resin (C) is 0 to 30 parts by weight, preferably 0 to 0 parts by weight. It is in the range of 20 parts by weight.

Calcium ion exchanged amorphous silica
Fine Particles (D) In the composition of the present invention, the (D) component, calcium ion-exchanged amorphous silica fine particles (hereinafter sometimes abbreviated as “ion-exchanged silica”), is a fine porous silica carrier. These are silica fine particles into which calcium ions have been introduced by ion exchange. The ion-exchanged silica compounded in the coating film is ion-exchanged with H ⁺ ions transmitted through the coating film, and calcium ion Ca, which is a rust preventive seed ion,
It is believed that ²⁺ is released to protect the metal surface.
Commercially available ion-exchanged silica is SHIELDEX
(Shielddex, registered trademark) C303, AC-3,
C-5 (both are WR Grace & C
o. And the like).

Phosphate modified with magnesium compound
(E) In the composition of the present invention, a phosphate-based rust-preventive pigment modified with a magnesium compound (E) (hereinafter, may be abbreviated as “modified phosphate pigment”) may be used. A water-insoluble condensed phosphate or phosphoric acid-based layered compound, a magnesium compound and a rust-preventive rust-free pigment containing no harmful metals, in the present invention, aluminum plating It is an effective component for improving the corrosion resistance of steel sheets.

The water-insoluble condensed phosphate which can constitute the modified phosphate pigment (E) is a condensed phosphate used as a rust preventive pigment, and has a solubility in water of P as ₂ O ₅ include: 10 g / l water are preferred. Representative examples of the water-insoluble condensed phosphates include, for example, aluminum pyrophosphate, calcium pyrophosphate, tin pyrophosphate, cerium pyrophosphate, copper pyrophosphate, iron pyrophosphate, titanium pyrophosphate, magnesium pyrophosphate, and pyrophosphate Pyrophosphates such as manganese phosphate; tripolyphosphates such as aluminum dihydrogen triphosphate and iron tripolyphosphate; aluminum metaphosphate, iron metaphosphate, calcium metaphosphate, tin metaphosphate, cerium metaphosphate, manganese metaphosphate, molybdenum metaphosphate, Examples thereof include metaphosphates such as silver metaphosphate, and aluminum dihydrogen triphosphate and aluminum metaphosphate are particularly preferable from the viewpoint of rust prevention and the like.

The phosphoric acid-based layered compound capable of constituting the modified phosphate pigment (E) is selected from the group consisting of tetravalent metal layered phosphates, such as M (HPO ₄ ) ₂ .XH ₂ O.
[Where M is a tetravalent metal such as Ce, Ti, Zr and Sn, and X is a number of 0 to 2]. Representative examples of the phosphoric acid-based layered compound,
For example, layered cerium phosphate, layered titanium phosphate, layered zirconium phosphate, layered tin phosphate and the like can be mentioned.

The modified phosphate pigment (E) is obtained by modifying the water-insoluble condensed phosphate or the phosphoric acid-based layered compound.
As the magnesium compound that can constitute
For example, inorganic magnesium salts such as magnesium oxide, hydrous magnesium hydroxide, magnesium carbonate, basic magnesium carbonate, magnesium phosphate, magnesium borate, magnesium metaborate and magnesium silicate; organic magnesium such as magnesium stearate and organic magnesium sulfonate Salts can be mentioned, but magnesium oxide, hydrous magnesium hydroxide, magnesium carbonate and magnesium borate are particularly preferred.

In the modified phosphate pigment (E), the mixing ratio of the water-insoluble condensed phosphate or the phosphoric acid-based layered compound and the magnesium compound is 10/1 to 10 by weight in the former / latter. It is preferable that the ratio is in the range of / 10 from the viewpoints of rust-preventive power and an effect of improving paint stability by neutralizing pH.

The modified phosphate pigment (E) is a mixture of the above-mentioned condensed phosphate which is hardly soluble in water or the above-mentioned phosphoric acid-based layered compound and a magnesium compound. , Dry mixing and wet mixing.

Triazole Compound (F) In the composition of the present invention, the triazole compound as the component (F) is effective for improving corrosion resistance and water adhesion of a general portion and an edge portion as an end face of an aluminum-plated steel sheet. Component.

Examples of the triazole compound (F) include 1,2,4-triazole, 3-amino-1,2,2,
4-triazole, 4-amino-1,2,4-triazole, 3-mercapto-1,2,4-triazole,
-Amino-3-mercapto-1,2,4-triazole, 1H-benzotriazole, 1-hydroxybenzotriazole, 6-methyl-8-hydroxytriazolopyridazine, 6-phenyl-8-hydroxytriazolopyridazine, 5- Hydroxy-7-methyl-1,3,8
-Triazaindolizine, among which 3-
Mercapto-1,2,4-triazole, 5-amino-
3-mercapto-1,2,4-triazole is preferred from the viewpoint of anticorrosion properties.

The amounts of the ion-exchanged silica (D), modified phosphate pigment (E) and triazole compound (F) in the coating composition of the present invention are the same as those of the above components (A), (B) and (C). With respect to the total amount of 100 parts by weight of a certain film-forming resin component, it is within the following range, the corrosion resistance of the general portion of the aluminum-plated steel sheet on which the coating film of the coating composition of the present invention is formed, It is suitable from the viewpoints of anticorrosion, water resistance of the coating film and the like.

Ion exchange silica (D): 5 to 50 parts by weight, preferably 10 to 30 parts by weight, modified phosphate pigment (E): 5 to 50 parts by weight, preferably 10 to 30 parts by weight, triazole compound ( F): 0.1 to 10 parts by weight,
Preferably 1 to 8 parts by weight.

The coating composition of the present invention comprises a film-forming resin component comprising the aqueous resin (A), an aqueous acrylic resin (B) and an aqueous melamine resin (C), if necessary, D), the modified phosphate pigment (E), and the triazole compound (F), and can be substantially composed of water, and if necessary, a component other than the components (D), (E), and (F). Non-chrome anti-corrosion pigment known per se; phosphoric acid group-containing acrylic resin; organic solvent, curing catalyst, coloring pigment, extender pigment, neutralizing agent, defoamer known per se for paint, coating surface conditioner, sedimentation prevention An additive such as an agent may be contained.

As the chromium-free rust preventive pigment which may be contained as required, at least one kind of rust preventive pigment selected from a zinc compound and a molybdate compound is suitable, and it contributes to the improvement of corrosion resistance. is there. Specific examples of the chromium-free rust preventive pigment include zinc oxide, zinc phosphate, phosphorous zinc silicate, aluminum zinc phosphate, calcium zinc phosphate, zinc zinc cyanamide, zinc-treated aluminum polyphosphate, zinc calcium molybdate, and molybdate. Zinc, zinc phosphomolybdate, aluminum phosphomolybdate and the like can be given. Among them, zinc oxide, zinc phosphate and zinc calcium molybdate are preferred.

When a non-chromium rust preventive pigment is blended,
The compounding amount is based on 100 parts by weight of the total of the film-forming resin components (A), (B) and (C).
Suitably, it is in the range of 1 to 50 parts by weight, preferably 2 to 40 parts by weight.

The phosphate group-containing acrylic resin is a resin having a phosphate group in a side chain of the acrylic resin.
2- as part of the monomer component constituting the acrylic resin
It can be obtained by using a polymerizable unsaturated monomer having a phosphate group such as (meth) acryloyloxyethyl acid phosphate and copolymerizing it with another monomer such as an alkyl ester of acrylic acid or methacrylic acid. Generally, the phosphoric acid group-containing acrylic resin preferably has a weight average molecular weight in the range of 2,000 to 100,000. The phosphoric acid group-containing acrylic resin can contribute to the improvement of the water resistance of the coating film of the aluminum-plated steel sheet on which the coating film is formed. When the phosphoric acid group-containing acrylic resin is blended, the amount is preferably 0.1 to 20 parts by weight, more preferably 1 to 15 parts by weight, based on 100 parts by weight of the film-forming resin component.

The above-mentioned organic solvent is added as necessary for improving the coating property of the composition of the present invention, and the like.
A hydrophilic organic solvent capable of dissolving or dispersing the resins (A), (B) and (C) in water is suitably used. Specifically, for example, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol Examples thereof include ether solvents such as monobutyl ether, alcohol solvents such as methanol, ethanol, isopropanol, and butanol, and acetone. These may be used alone or as a mixture of two or more.

The curing catalyst is an aqueous melamine resin (C)
Is blended as necessary to promote the reaction between the aqueous resin (A) or the aqueous acrylic resin (B) and the aqueous melamine resin (C), and the sulfonic acid compound or the sulfonic acid An amine neutralized product of the compound is preferably used. Representative examples of the sulfonic acid compound include p-toluenesulfonic acid, dodecylbenzenesulfonic acid, dinonylnaphthalenesulfonic acid, and dinonylnaphthalenedisulfonic acid. The amine in the amine neutralized product of the sulfonic acid compound may be any of a primary amine, a secondary amine, and a tertiary amine. Among these, an amine-neutralized product of p-toluenesulfonic acid and / or an amine-neutralized product of dodecylbenzenesulfonic acid are preferred from the viewpoints of paint stability, reaction promoting effect, and physical properties of the obtained coating film. .

When a curing catalyst is blended, it is usually blended in an amount of 0.1 to 2.0 parts by weight of the sulfonic acid compound based on 100 parts by weight of the total amount of the film-forming resin component.

As the extender, at least one selected from baryta, calcium carbonate, and a mixed crystal of calcium carbonate and magnesium carbonate is preferably used from the viewpoint of coating film hardness, coating film properties, coating film adhesion and the like. Can be used.
The blending amount of the extender is not particularly limited,
It is usually used in an amount of 200 parts by weight or less, preferably 30 to 150 parts by weight, based on 100 parts by weight of the total amount of the film-forming resin component.

Next, a method of applying the composition of the present invention will be described.

The composition of the present invention can be applied to, for example, metals, mortars, cements, plastics, glass, etc., and can be suitably applied to metals, especially steel plates.
As the steel sheet used as the object to be coated, cold-rolled steel sheet, hot-dip galvanized steel sheet, electro-galvanized steel sheet, zinc alloy-plated steel sheet, aluminum-plated steel sheet, stainless steel sheet, copper-plated steel sheet, tin-plated steel sheet, lead-tin alloy plating Examples thereof include steel sheets (turn sheets) and steel sheets obtained by subjecting these steel sheets to a chemical conversion treatment such as a phosphate treatment or a chromate treatment and / or an organic coating treatment. As the steel sheet subjected to the chemical conversion treatment and / or the organic film treatment, the above-mentioned steel sheet was subjected to the chemical treatment such as the one subjected to the chemical treatment, the one subjected to the organic film treatment, the chromate treatment, etc., and then subjected to the organic film treatment. Things can be mentioned. As organic film treatment,
Film formation by an acrylic emulsion, film formation by a phenoxy resin, film formation by an epoxy resin, and the like can be given. The thickness of the organic film in the organic film treatment is not particularly limited, but is usually 0.3 to 3
About μm is appropriate.

Among the substrates to be coated, chemical conversion treatment and / or
Alternatively, an aluminum-plated steel sheet which may be subjected to an organic film treatment can be particularly preferably used. These steel sheets may be in the form of a sheet before being processed or may be formed.

The composition of the present invention is suitably used as an undercoat or a one-coat finish, and is coated on the steel sheet by a known method such as a shower coating method, a roll coating method, a spray method, a brush coating method, and a dipping method. Can be painted. The film thickness of the coating film obtained from the composition of the present invention is not particularly limited, but when used as an undercoat paint, it is usually in the range of 2 to 40 μm, preferably 5 to 30 μm, and is a one-coat finish paint. When it is used, the thickness is usually in the range of 8 to 50 μm, preferably 10 to 40 μm.

The coating film of the composition of the present invention is usually dried when the coated material is continuously baked by a coil coating method or the like.
50 ° C., preferably 180 to 230 ° C.
This is a condition for about 60 seconds, and when baking is performed in a batch system, it can be usually performed by baking at 80 to 160 ° C. for about 10 to 30 minutes.

[0057]

The present invention will be described more specifically with reference to the following examples. Hereinafter, “parts” and “%” are based on weight unless otherwise specified.

Production Example 1 Oil length 4 modified with tall oil fatty acid and linseed oil fatty acid
2%, an alkyd resin having an acid value of 40 mgKOH / g is neutralized with triethylamine in an equivalent amount, and the non-volatile content is 68
%, And then ethylene glycol monobutyl ether was added to obtain an aqueous alkyd resin solution having a nonvolatile content of 50%.

Production Examples of Aqueous Coating Compositions Examples 1 to 12 and Comparative Examples 1 to 8 Using the aqueous alkyd resin solution having a nonvolatile content of 50% obtained in Production Example 1 above, the pigments shown in ) And a rust inhibitor were mixed and dispersed in a pigment as shown in Table 1, and then the remaining components shown in Table 1 were added to the obtained dispersion, and deionized water was added to obtain a viscosity of about 500 centipoise [Brookfield viscometer at 20 ° C (6r
pm)]. The blending amounts in Table 1 are indicated by nonvolatile components.

(Note) in Table 1 below has the following meanings.

(* 1) Aqueous epoxy ester A: an epoxy ester emulsion having a nonvolatile content of 60%, manufactured by trade name “Watersol S118” (manufactured by Dainippon Ink and Chemicals, Inc.). (* 2) Water-based epoxy ester B: trade name "CD54
0 ”[manufactured by Dainippon Ink and Chemicals, Inc.]
% Epoxy ester emulsion.

(* 3) Aqueous melamine resin: Methyl etherified melamine resin having a trade name of “CYMER 303” (manufactured by Mitsui Cytec Co., Ltd.).

(* 4) Aqueous acrylic resin: trade name “AD
69 "(manufactured by Kanebo Corporation), an acrylic resin emulsion having a nonvolatile content of 48%.

(* 5) Shielddex C303:
R. Grace & Co. Brand name, calcium ion-exchanged amorphous silica fine particles.

(* 6) Shielddex AC-5:
R. Grace & Co. Brand name, calcium ion-exchanged amorphous silica fine particles.

(* 7) K-White 450H: trade name, manufactured by Teica Co., Ltd., a phosphate-based rust preventive pigment modified with a magnesium compound, obtained by wet mixing a magnesium compound with aluminum dihydrogen tripolyphosphate. .

(* 8) Phosphoric acid group-containing acrylic resin: the constituent monomer component is styrene / n-butyl acrylate /
2-hydroxyethyl methacrylate / 2-methacryloyloxyethyl acid phosphate = 30/40 /
A 10/20 (weight ratio) phosphoric acid group-containing acrylic resin having a resin acid value of 95 mgKOH / g and a hydroxyl value of 43 mgK
OH / g, having a weight average molecular weight of about 20,000.

Preparation of Test Coated Plates The aqueous coating compositions obtained in Examples 1 to 12 and Comparative Examples 1 to 8 were coated on a 1.0 mm-thick aluminum-plated steel plate (trade name: Ulster, manufactured by Nissin Steel Co., Ltd.). ) Was applied by a dip coating method and forcedly dried to prepare a test coated plate. Each of the dry film thicknesses was about 23 μm. The forced drying conditions were as follows: each of the aqueous coating compositions obtained in Examples 1 to 6 and Comparative Examples 1 to 3 was baked at 130 ° C. for 20 minutes, and each of the aqueous coating compositions obtained in Examples 7 to 12 and Comparative Examples 4 to 8 was used. The aqueous coating composition was baked at 110 ° C. for 20 minutes.

Various performance tests were performed on the obtained test coated plates based on the following test methods. The test results are shown in Table 1 below.

Test Method Adhesion: JIS K-5400 8.5.2 (199
0) In accordance with the crosscut-tape method, 11 parallel vertical and horizontal straight lines were drawn at 1 mm intervals so as to reach the base material with a cutter knife on the coating surface of the test coated plate at 1 mm intervals.
100 × 1 mm squares were created. A cellophane adhesive tape was adhered to the surface, and the degree of peeling of the squares when the tape was abruptly peeled was observed and evaluated according to the following criteria. ：: No peeling of the coating film was observed at all. Δ: The coating film was slightly peeled, but 90 or more squares remained. ×: The coating film was considerably peeled, and the number of remaining squares was less than 90.

Corrosion protection: A test coated plate was cut into a size of 75 × 150 mm, and subjected to a salt spray test for 480 hours in accordance with JIS Z-2371, and the coated plate after the test was visually inspected for the degree of rust and rust in the general part. And the maximum rust width from the edge, the edge rust width (m
m) was measured.

Degree of rusting and rusting in general part ：: No rust is generated in general part △: Slight spot rust is generated in general part X: Many rusts are generated in general part .

Water adhesion: The test coated plate was placed in warm water of 40 ° C. for 1 hour.
After immersion for 20 hours, JIS K-5400 8.5.2.
(1990) In accordance with the crosscut-tape method, 11 parallel vertical and horizontal straight lines were drawn at 1 mm intervals on the surface of the coating film of the test coating plate so as to reach the substrate with a cutter knife at 1 mm intervals. 100 squares of 1 mm were created. A cellophane adhesive tape was adhered to the surface, and when the tape was rapidly peeled, the number of squares remaining without peeling out of 100 squares was indicated.

[0074]

[Table 1]

[0075]

[Table 2]

[0076]

The coating composition of the present invention is aqueous,
Since it does not need to contain harmful heavy metals, it is advantageous from the viewpoint of pollution prevention.

The aqueous coating composition of the present invention can form a coating film having excellent anticorrosion properties without containing harmful heavy metals.
The coated steel sheet obtained by coating the water-based coating composition of the present invention on an aluminum-plated steel sheet shows good anticorrosion properties in a general part and an edge part, and also has good water adhesion resistance. Therefore, the turnsheet coated plate containing harmful lead can be replaced with an aluminum-plated steel plate coated plate by using the aqueous coating composition of the present invention, which is advantageous from the viewpoint of global environmental protection.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (reference) C09D 163/00 C09D 163/00 167/08 167/08 F term (reference) 4D075 CA33 DB07 EA06 EB32 EB33 EC02 EC03 EC03 EC07 EC15 4J038 CG142 DA162 DB351 DD121 GA14 HA216 HA246 HA416 HA446 JB35 KA08 KA14 KA15 KA20 MA08 MA10 NA03 PA07 PC02

Claims (4)

[Claims] (A) 50 to 100 parts by weight of at least one aqueous resin selected from an aqueous alkyd resin and an aqueous epoxy ester resin; (B) 0 to 50 parts by weight of an aqueous acrylic resin; and (C) an aqueous melamine resin. (D) 5 to 50 parts by weight of calcium ion-exchanged amorphous silica fine particles, (E) phosphorus modified with a magnesium compound, based on 100 parts by weight of the total amount of the film-forming resin component consisting of An aqueous coating composition comprising 5 to 50 parts by weight of an acid salt-based rust preventive pigment and 0.1 to 10 parts by weight of a triazole compound (F). 2. The composition according to claim 1, further comprising:
The composition according to claim 1, wherein the composition contains 1 to 50 parts by weight of at least one non-chromium rust preventive pigment selected from a zinc compound and a molybdate compound based on 00 parts by weight. 3. Further, the total amount of the film-forming resin component is 1
The phosphoric acid group-containing acrylic resin is used in an amount of 0.1 part by weight.
3. The composition according to claim 1, comprising 1 to 20 parts by weight. 4. The method according to claim 1, wherein the aluminum-plated steel sheet substrate, which may be subjected to a chemical conversion treatment and / or an organic film treatment, is provided.
A coated article based on an aluminum-plated steel sheet having a coating film formed from the water-based coating composition as described above.