WO2002066703A1 - Water-based surface-treating agent for plated metal sheet, surface-treated metal sheet, and process for producing the same - Google Patents

Abstract

A water-based surface-treating agent which comprises an acrylic resin, water, and colloidal silica having a solid concentration of 5 to 35 wt.%, characterized in that the acrylic resin is a polymer having a glass transition temperature of 0 to 30°C obtained by polymerizing (a) 15 to 76 wt.% unsaturated (meth)acrylic ester monomer represented by the following general formula (1) (1) (wherein R1 is hydrogen or methyl and R2 is C¿1-8? linear or branched alkyl), (b) 2 to 10 wt.% a, β-ethylenically unsaturated monomer having a carboxyl group in the molecule, (c) 2 to 10 wt.% α, β-ethylenically unsaturated monomer having a hydroxyl group in the molecule, (d) 10 to 30 wt.% styrene, (e) 10 to 30 wt.% acrylonitrile, and (f) 0 to 10 wt.% unsaturated monomer copolymerizable with these monomers. Also provided is a surface-treated metallic material produced with the agent.

Description

 Description Aqueous surface treatment agent for plated metal sheet, surface-treated metal sheet and method for producing the same

 The present invention relates to a surface-treated metal sheet having excellent corrosion resistance in addition to flat surface corrosion resistance, processed portion corrosion resistance, solvent resistance, coating adhesion and weldability, and an aqueous surface treatment agent capable of obtaining the same. About the method. Background art

 Zinc and zinc-coated steel sheets have been widely used for home appliances and building materials. These steel sheets are, as they are, inadequate in corrosion resistance and topcoat paintability, and are therefore subjected to chromate conversion treatment and phosphoric acid conversion treatment. After that, shaping or painting, such as pressing or bending, is often performed, but depending on the intended use, it is not uncommon to use it without painting. When used without painting, surface-treated steel sheets called chromate conversion treated steel sheets have been used in many cases, but they have problems such as sticking of fingerprints and damage during forming and assembly. . Therefore, in order to solve these problems, an organic composite steel sheet has been used, in which an organic resin layer with a thickness of about 1 μm is formed on the surface of a zinc-based plated steel sheet after a close mate treatment. Was.

This organic composite steel sheet is required to have various film properties such as corrosion resistance, solvent resistance, and overcoating property in addition to fingerprint resistance. Among these performances, in recent years, the required level for surface appearance quality, particularly scratch resistance, has been increasing. This is because in the home appliance industry, from the viewpoint of saving processes and costs, it is used as it is without painting after press molding. Recently, press molding with no oil or quick-drying oil has been increasing. Under these press forming conditions, scratches are likely to occur on the surface of the steel sheet due to sliding with the mold, and when transporting the formed product, the molded products are separated from each other or The container (such as a cardboard box) rubs and the surface of the molded product is scratched. Such scratched parts are inferior in corrosion resistance to ordinary organic-coated steel sheet surfaces, and are markedly scratched in appearance, so that quality deterioration is inevitable.

 For this reason, several technologies have been proposed for surface-treated steel sheets that take into account not only corrosion resistance and topcoat paintability but also scratch resistance. Examples of such techniques include the methods described in Japanese Patent Application Laid-Open Nos. 3-171889, 6-104799, and 6-292589. There is.

 Japanese Patent Application Laid-Open No. 3-171189 discloses a method for a resin film in which a urethane-modified polyolefin resin is mixed with fluorine resin particles and silicide particles. The feature of this method is that the damaged part is protected by using fluororesin particles, but in order to disperse the fluororesin particles uniformly in an aqueous solution, it is necessary to use a surfactant. Indispensable, the use of this surfactant resulted in a low level of corrosion resistance overall, and no satisfactory corrosion resistance could be obtained.

Japanese Patent Publication No. 6-104799 discloses a method relating to a film containing a polyester resin, a crosslinking agent and a polyethylene wax having an average molecular weight of 2000 to 800. In this method, since the polyester resin is used as the base resin, the hydrolysis resistance of the film itself was insufficient, and satisfactory corrosion resistance could not be obtained. Has active hydrogen in the molecule There is disclosed a method relating to a skin in which spherical polyethylene particles and chain colloidal silicic acid are contained in a resin in which a room temperature crosslinkable epoxy resin is contained in a urethane resin. Colloidal silica has the property of increasing the coefficient of friction by adhering to a solid surface, and when chain colloidal silicity like this method is used, the scratch resistance is reduced due to the structure of the colloidal silica itself. . For this reason, spherical polyethylene wax is blended in this method, but since the drying temperature is lower than 100 ° C, the polyethylene wax is embedded in the resin film and lubricity is insufficient. And satisfactory scratch resistance cannot be obtained. Disclosure of the invention

 The present invention is intended to solve the problems of the prior art, and has a surface treatment excellent in corrosion resistance and scratch resistance as well as flat portion corrosion resistance, solvent resistance, topcoat paintability and weldability. Provided are a metal material, an aqueous surface treatment agent capable of obtaining the metal material, and a production method.

 The present inventors have conducted intensive studies on means for solving the above-mentioned problems, and as a result, it has been found that it is effective to use an aqueous surface treating agent containing silica and an acrylic resin polymerized from a specific monomer. Have been newly found, and the present invention has been completed.

 That is, the gist of the present invention is as follows.

 (1) Acrylic resin, 5 to 35 mass in terms of water and solid content

Containing _0/0 of colloidal silica, the accession Lil resin is, on a solids mass terms (a) the following general formula (1) H ₂ C = C—— C00R ² (1)

(In the formula, R ¹ is hydrogen or a methyl group, and R ² is a linear or branched alkyl group having 1 to 8 carbon atoms.)

15 to 76% by mass of a (meth) acrylic acid ester unsaturated monomer represented by the following formula: and (b) 2 to 10% by mass of a carboxyl group in the molecule. (C) 2 to 10 mass ⁰ / having a hydroxyl group in the molecule. And J3—ethylenically unsaturated monomer, (d) 10-30 mass ⁰ / o styrene, and (e) 10-30 mass ⁰ / o atalyloni trinole, (F) A polymer obtained by a polymerization reaction with 0 to 10% by mass of an unsaturated monomer copolymerizable with these monomers, and having a glass transition temperature of 0 to 30%. An aqueous surface treatment agent characterized by a temperature of ° C.

 (2) An unsaturated monomer having at least one functional group selected from a glycidyl group, an aziridinyl group, a methylol group and a silanol group in the molecule, wherein (f) in the acryl-based resin is The aqueous surface treating agent according to the above (1), which comprises:

 (3) The above-mentioned (1) or (2), wherein the aqueous surface treating agent further contains 35% by mass or less of a polyolefin wax dispersion in terms of solid content. The aqueous surface treating agent according to (1).

(4) Acrylic resin and 5 to 35 mass in solid content on the plated metal plate. /. Has an organic-inorganic composite film containing co port Idarushiri force 0. 3 ~ 5. 0 g / m 2, the accession Lil resin is in solid mass in terms

(a) 15 to 76% by mass of a (meth) acrylic acid ester unsaturated monomer represented by the above general formula (1); and (b) 2 to 10 having a carboxyl group in the molecule. % By mass of the ethylenically unsaturated monomer and ( c) intramolecular 2 to 1 0% by weight of o ;, having hydroxyl groups at - and an ethylenically unsaturated monomer, and (d) 1 0~ 3 0 mass _^0/0 of styrene, (e) 1 0 to 30 mass ⁰ /. A polymer obtained by a polymerization reaction of acrylonitrile of the formula (f) with 0 to 10% by mass of an unsaturated monomer copolymerizable with these monomers, and having a glass transition temperature Is a surface-treated metal material having a temperature of 0 to 30 ° C.

 (5) Constituting the acrylic resin (f) Force A compound having at least one functional group selected from the group consisting of glycidyl group, aziridinyl group, methylol group and silanol group in the molecule. The surface-treated metal material according to the above (4), which comprises a saturated monomer.

 (6) The surface according to (4) or (5), wherein the organic-inorganic composite film further contains 35% by mass or less of a polyolefin wax dispersion in terms of a solid content. Processing metal material.

(7) The aqueous surface treating agent according to any one of the above (1) to (3), on a plated metal plate or a metal plate provided with a base treatment, having a dry solid content of 0.3 to 5. A method for producing a surface-treated metal material, comprising applying an Og / m ² coating and then drying to form an organic-inorganic composite film. BEST MODE FOR CARRYING OUT THE INVENTION

 A first feature of the present invention is a copolymer obtained by copolymerizing several types of monomers having an ethylenic double bond as an acrylic resin serving as a base, and an appropriate amount of the copolymer. It consists in using a copolymer obtained from the polymerization of the appropriate monomer species. The method for polymerizing the polymer used in the present invention is not particularly limited, but a method based on suspension polymerization and emulsion polymerization is preferred.

Such monomers include, for example, acrylic acid, methacrylic acid, Leic acid, maleic anhydride, fumaric acid, crotonic acid, itaconic acid, citraconic acid, cinnamic acid, 2-hydroxyhexyl (meta) acrylate, 2-hydric acid Doxypropyl (meta) acrylate, 3—hydroxypropyl (meta) acrylate, 2—hydroxybutyl (meta) acrylate, 3—hydroxybutyl (meta) acrylate 4-hydroxy butyl (meta) acrylate, 2-hydroxyl-methyl (aryl) ether, 3-hydroxypropynole (meta) aryl, 4-hydroxybutyl (meta) aryl ether, Alinorea Ruco I. Glycidyl (meta) atalylate, 2 — (1 — aziridinole) ethyl atalylate, butyl trimethoxysilane, Nyl triethoxysilane, arinoleglycidyl ether, iminol methacrylate, N-methylol (meth) acrylinoleamide, N-Methoxymethyl (meth) acrylylamide, N —Ethoxymethyl (meta) atalinoleamide, N—butoxymethyl (meth) acrylamide, (meth) acrylylamide, N—methyl (meta) acrylamide, N, N—dimethyl (meta) Acrylamide, N-dimethylamino propyl (meth) Acrylamide, butyl formate, butyl acetate, vinyl butyrate, butyl acrylate, styrene, α-methyl styrene, t-butynolestyrene, vinylinoletone, (meth) Atari lonitrile, ditolyl citrate, (meta) acrylate loxiche Rufosphate, bis (meta) acryloxyl phosphate, (meta) acryloxyphenyl acid phosphate, (meta) methyl acrylate, (meta) Ethyl acrylate, (meth) propyl acrylate and its isomers, (meth) butyl acrylate and its isomers, (meth) pentyl acrylate and its isomers, (meta) acyl Hexyl lylate and its isomers and the like. The terms “(meta) acryl”, “(meta) attribute”, “ The statements “(meta) aryl j” and “(meta) at lip” are “acryl”, “metacryl”, “atalylate J” or “ “Metacrylate”, “aryl” or “metaryl”, and “ataryloxy J” or “metacryloxy”, and similar in other similar notations. is there.

As the acrylic resin, (a) the following general formula (1) R ¹

 I

H ₂ C = C—— G00R ² … (1)

(In the formula, R ¹ is hydrogen or a methyl group, and R ² is a straight-chain or branched alkyl group having 1 to 8 carbon atoms.)

15 to 76% by mass of (meth) acrylic acid ester unsaturated monomer represented by the formula: (b) 2 to 10% by mass having a carboxyl group in the molecule (a, | 3—ethylenic An unsaturated monomer, and (c) an ethylenically unsaturated monomer having a hydroxyl group in the molecule of 2 to 1 ° mass ⁰ / .; and an ethylenically unsaturated monomer of (d) 10 to 30% by mass. A mixture of styrene, (e) 10 to 30% by mass of acrylonitrile, and (f) 0 to 10% by mass of an unsaturated monomer copolymerizable with these monomers. It is necessary to use a polymer obtained by a polymerization reaction.

The (meth) acrylic acid ester unsaturated monomer (a) used in the present invention is represented by the above general formula (1). Examples include methyl (meth) acrylate, ethyl (meta) acrylate, n-propyl (meta) acrylate and its isomers, n-butyl (meth) Acrylate and its isomers, n-pentyl (meta) acrylate and its isomers, n-hexyl (meth) acrylate and its isomers, n-heptyl (meta) Atalylate and its isomers, n-octyl (Meta) atalylate and its isomers.

 The amount of such an unsaturated monomer (a) is 100 mass in total of the unsaturated monomers (a) to (f) constituting the acrylic resin. /. 15 to 76% by mass, preferably 3 ° to 70% by mass. If the amount of the unsaturated monomer (a) is less than 15% by mass, the resulting polymer film lacks flexibility, and cracks occur in the film during film formation, making it impossible to obtain sufficient corrosion resistance. . On the other hand, when the amount is more than 76% by mass, the formed film has poor solvent resistance, which is not preferable.

 The α, β-ethylenically unsaturated monomer (b) having a carboxyl group in the molecule used in the present invention includes, for example, acrylic acid, methacrylic acid, maleic acid , Maleic anhydride, fumaric acid, crotonic acid, itaconic acid, citraconic acid, cinnamic acid and the like. The amount of such unsaturated monomer (b) is from 2 to L based on the total of 100% by mass of the unsaturated monomers (a) to (f) constituting the acrylic resin. 0 mass%, more preferably 2.5 to 8 mass%. When the amount is less than 2% by mass, the adhesion of the film to the steel sheet is inferior. When the amount exceeds 10% by mass, the film is poor in corrosion resistance and water resistance.

Examples of the ethylenically unsaturated monomer (c) having a hydroxyl group in the molecule used in the present invention include 2-hydroxylethyl (meth) atalylate and 2-hydroxypropyl ( Methacrylate, 3—hydroxypropyl (meta) acrylate, 2—hydroxybutyl (meta) acrylate, 3—hydroxybutyl (meta) acrylate , 4-hydroxybutyl (meta) acrylate, 2-hydroxyl (meth) aryl ether, 3-hydroxypropyl (meth) aryl ether, 4-hydroxypropyl (meth) aryl ether, allyl alcohol, etc. Is mentioned. The amount of such an unsaturated monomer (c) may be adjusted according to the amount of the unsaturated monomer (a) constituting the acrylic resin. ) To (f) are 2 to 10% by mass, more preferably 2.5 to 8% by mass, based on the total 100% ⁰ / o of (f). 2 mass. If the ratio is less than / _0, the adhesion of the film to the steel sheet is poor.

1 0-3 0 weight amount is the total 1 0 0 wt% of the unsaturated monomers constituting the accession Lil resin (a) ~ (ί) styrene (d) used in the present invention ⁰ /. And more preferably 12 to 25% by mass. If the amount is less than 10% by mass, the formed film is inferior in scratch resistance, and if it exceeds 30% by mass, the corrosion resistance of the film in the processed part is inferior. The amount of the acrylonitrile (e) used in the present invention is from 10 to 100% by mass based on the total of 100% by mass of the unsaturated monomers (a) to (f) constituting the acryl-based resin. It is 30% by mass, more preferably 15 to 28% by mass. When the amount is less than 10% by mass, the formed film is poor in solvent resistance, and when the amount exceeds 30% by mass, the water resistance and corrosion resistance of the film are inferior.

 The unsaturated monomer (f) is an unsaturated monomer other than (a) to (e) copolymerizable with (a) to (e), and the solvent resistance, adhesion, and It may be used for the purpose of further improving the scratch resistance and the like as long as the effects of the present invention are not impaired.

Examples of the unsaturated monomer (f) include (meth) acrylamide, N-methyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-dimethylaminopropyl (Meta) Unsaturated monomer containing amide group such as acrylamide, esterified unsaturated monomer such as butyl formate, vinyl acetate, butyl butyrate, butyl acrylate, styrene, α-methyl Aromatic unsaturated monomers such as styrene, t-butyl styrene, vinyl toluene, etc .; cyanated unsaturated monomers such as (meth) acrylonitrile, ditolyl citrate; and (meth) ata Re Unsaturated monomers containing a phosphoric acid group, such as loxoshetyl phosphate, bis (meta) acrylic acid loxoshetyl phosphate, (meta) acrylic acid phosphate acid phosphate, etc. Glycidyl (meta) atalylate, 2- (1-aziridinyl) ethyl acrylate, biertrimethoxysilane, vinyltriethoxysilane, aryl glycidinoleate enolate, imino N-methylol (meth) acrylinoleamide, N-methoxymethyl (meta) acrylamide, N-ethoxymethyl (meta) acryloamide, Unsaturated monomer having a functional group capable of reacting with a hydroxyl group or a carboxyl group such as N-butoxymethyl (meth) acrylate And the like. At least one of them is preferably an unsaturated monomer having a functional group capable of reacting with a hydroxyl group or a hydroxyl group, more preferably a glycidyl group, an aziridinyl group, a methylol group, or a silanol group. It is an unsaturated monomer containing a mono group. Such compounds include, for example, glycidyl (meta) acrylate, 21- (1-aziridinyl) ethyl acrylate, biertrimethoxysilane, vinyltriethoxysilane, and arylglycidyl Ether, iminol methacrylate, acryloyl olemorphin, N-methylol (meta) acrylyl amide, N-methoxymethyl (meta) acrylyl amide, N—ethoxymethyl (meta) acrylate Lilamide, N-butoxymethyl (meta) acrylamide. When the amount of the unsaturated monomer (f) exceeds 10% by mass with respect to 100% by mass of the total of the unsaturated monomers (a) to (f) constituting the acrylic resin, It is not preferable because the viscosity of the polymer is easily increased, the pot life of the aqueous surface treating agent is shortened, and a uniform film cannot be formed and the corrosion resistance is deteriorated.

The glass transition temperature of the acrylic resin used in the present invention is preferably 0 to 30 ° C. The glass transition temperature of the acryl resin is not more than 0 ° C Unsatisfactory is not preferable because the formed film has poor blocking resistance.

. On the other hand, when the temperature is higher than 30 ° C, the film forming property is deteriorated, and the corrosion resistance of the processed portion is poor.

The glass transition temperature (T g) in the present invention is a value calculated using the T g of a homopolymer of a monomer component, and can be determined by the following equation. ig Tg, Tg ₂ Tg _n where T g is the glass transition temperature of the polymer, T _gl , T g ₂ ,

• T g _n is the glass transition temperature of the homopolymer of each monomer component,, W _2, ... * w _n represents the mass fraction of each monomer, + ₂ + · · ·

+ w _n = 1. The glass transition temperature of the homopolymer of each monomer is determined according to JISK7121.

 The amount of colloidal silicity in the aqueous surface treating agent and the film of the surface-treated metal material of the present invention is 5 to 35% by mass in terms of solid mass. When the amount of colloidal silicide is less than 5% by mass, the corrosion resistance of the film is inferior. On the other hand, if it exceeds 35% by mass, the binder effect of the resin is small, and the corrosion resistance is undesirably reduced. Note that the particle size and type of colloidal silica are not particularly limited in the present invention. For example, Snowtex O, N, and C manufactured by Nissan Chemical Industries, and Adelaide AT manufactured by Asahi Denka Kogyo Co., Ltd. — Commercial products such as 20 N, A, and Q are applicable.

 In the present invention, a polyolefin wax dispersion can be incorporated into the aqueous surface treating agent and the organic-inorganic composite film in order to improve the scratch resistance of the surface-treated metal material.

Polypropylene wax disposable purines include polyethylene wax, polypropylene wax, and polybutylene wax. Alternatively, a denatured polyolefin resin obtained by adding a polar group to these waxes is used in an emulsifier concentration of 5% or less, and preferably dispersed in water or an aqueous solution without using an emulsifier. The polar group can be introduced by oxidizing the polyolefin with an oxidizing agent such as oxygen, ozone or nitric acid in the presence of a catalyst (oxidized polyolefin wax), or atalylic acid, methacrylic acid, or methacrylic acid. Ethylenically unsaturated linoleic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid and other ethylenically unsaturated solvonic acid monomers and polyolefin resins are dissolved in benzol and the like, and polymerization initiators (peroxide, (Dox, heavy metal catalyst, etc.) and heated in a nitrogen stream to make a graph. The mass average particle diameter of the polyolefin wax disposable ion is preferably from 0.1 to 5.0 μππι, more preferably from 1.0 to 4.0 μτη. If the mass average particle diameter is less than 0.1 zm, the particles are likely to aggregate and have poor stability, which is not preferable. On the other hand, if the mass average particle size exceeds 5.0 IX m, the dispersion stability of the particles is poor, which is not preferable. Further, the ratio of the mass average particle diameter to the number average particle diameter is preferably in the range of mass average particle diameter / number average particle diameter, that is, approximately 3.

 These polyolefin dispersions are preferably incorporated in the aqueous surface treating agent and the organic-inorganic composite coating in an amount of 35% by mass or less in terms of solid content. If it exceeds 35% by mass, paint adhesion is deteriorated, which is not preferable.

In the present invention, an organic-inorganic composite film having a solid content of 0.3 to 5.0 g / m ² is formed on a metal plate. If it is less than 0.3 g / m ² , it is not preferable because the coating is inferior in scratch resistance and the corrosion resistance in the processed portion is not good. On the other hand, if it exceeds 5.0 g Zm ² , it is not preferable because weldability is poor.

The aqueous surface treating agent used in the present invention includes a uniform film on the surface to be coated. Surfactants and thickeners called wettability improvers to obtain a coating, conductive substances for improving weldability, coloring pigments for improving design, matting materials, and solvents for improving film forming properties Etc. may be added as long as the effects of the present invention are not impaired.

 Examples of the metal plate with a base that can be used in the present invention include a zinc-plated metal plate, a zinc-nickel plated metal plate, a zinc-iron plated metal plate, a zinc-chrome plated metal plate, and a zinc-aluminum plated metal plate. Zinc-plated metal sheet, zinc-magnesium plated metal sheet, zinc-manganese plated metal sheet, etc. , Lead or lead alloy-plated metal, tin or tin alloy-plated metal, and a small amount of dissimilar metal elements or impurities in these plating layers such as copanoleto, molybdenum, tungsten, nickel, titanium, and black. Containing aluminum, manganese, iron, magnesium, lead, antimony, tin, copper, cadmium, arsenic, etc. And those in which inorganic substances such as silica or alumina, titania and the like are dispersed. Further, a multi-layer plated metal plate in combination with the above plating and other types of plating, for example, iron plating, iron-phosphorus plating, etc., can also be used.

 The aqueous surface treating agent of the present invention can be applied directly on such a plated metal plate. However, in order to sufficiently exert the effects of the present invention, first, a chromate treatment or a non-chromate treatment by a conventional method is used. It is preferable to form a base coat and then apply the aqueous surface treating agent of the present invention thereon to form a resin coat.

The chromate treatment includes an electrolytic chromate treatment in which a chromate film is formed by electrolysis, a film formation using a reaction with a material, and a reaction-type close-mate treatment in which excess processing liquid is washed away. Substrate with treatment liquid There is a coating-type chromatographic treatment in which a film is formed by coating without drying and washing with water, and any of the treatments can be employed in the present invention. Electrolytic non-chromate treatment to form a film, a film is formed using the reaction with the material, then reactive non-chromate treatment to wash away excess treatment liquid, apply the treatment liquid to the object, and wash with water There is a coating-type non-chromatizing treatment in which a film is formed by drying without drying, and any of these treatments can be employed in the present invention.

 By applying the aqueous surface treating agent of the present invention on the metal plate with the undercoat treated by the above-mentioned chromate treatment and drying it at a reaching plate temperature of 60 to 200 ° C., the organic and inorganic substances can be obtained. Form a composite coating. As a coating method, a conventional method such as a roll coating method, a dipping method, and an electrostatic coating method can be used. Example

 Hereinafter, the present invention will be described specifically with reference to Production Examples, Examples, and Comparative Examples. These examples are provided for illustrating the present invention and do not limit the present invention in any way.

 (1) Metal plate

 The metal plates shown in Table 1 were used.

Table 1 Types of metal plates and coating weight (plate thickness: 0.8 mm)

Symbol Type of metal plate

EG Electro-galvanized steel sheet (coating weight: 20 g / m ² )

 ZN Electric zinc-nickel plated steel sheet (Attached coating weight: 20 g

/ M ^2, nickel content: 1 2 wt%)

GI hot-dip galvanized steel sheet (coating weight: 60 g / m ² ) (2) Degreasing treatment

 Each of the above metal plates was degreased with a silicate alkaline degreasing agent Fine Cleaner 4336 (registered trademark, manufactured by Nippon Parkerizing Co., Ltd.). Specifically, the metal plate was treated with a degreasing agent at a concentration of 20 g / 1 at a temperature of 60 C by spraying for 2 minutes, and then spray-washed with tap water for 30 seconds.

 (3) Base treatment

(a) Reactive chromate treatment (metal plate: EG, ZN, GI) Using zinc chrome 357 (registered trademark, manufactured by Nippon Parkerizing Co., Ltd.), spray treatment at a liquid temperature of 50 ° C for 5 seconds. After washing with tap water and air-drying, a test plate was prepared. The goal Beam deposition amount in thickness is ² 0 mg / m 2.

(b) Coating-type chemical conversion treatment (metal plate: EG, ZN, GI) Zinc chrome 130 AN (registered trademark, manufactured by Nippon Pariki Rising Co., Ltd.) is applied to the metal plate by a roll coating method, and washed with water. Without drying, the sample was dried at an ambient temperature of 200 ° C. for 10 seconds to prepare a test plate. The reached plate temperature in this treatment was 100 ° C, and the target chromium adhesion amount was 40 mg / m ² .

(C) electrolytic click port formate process (metal plate: EG, ZN, GI) chromic acid 5 0 g / 1, of predetermined sulfate 0. 3 g current density 1 in a bath of Z 1 0 A / dm ² A test plate was prepared by applying an electric quantity to the metal plate to perform an electrolytic closing process on the metal plate, washing the plate with water, and then drying it at 200 ° C. for 8 seconds. The reached plate temperature in this treatment was 80 ° C, and the target chromium deposition amount was AO mg Zm ² .

 (4) Preparation of aqueous surface treatment agent

(A) Unsaturated (meth) acrylic acid ester monomer, (b) having a carboxyl group in the molecule a :,] 3-ethylenic Unsaturated monomers, (c) _α , β-ethylenically unsaturated monomers having a hydroxyl group in the molecule, (d) styrene, (e) atalylonitrile, (f) the unsaturated monomer can be a monomer copolymerizable, used in ratios shown in Table _3, to obtain a polymer a l ~ a 3 7 shown in Table 3. The numerical value in parentheses after the name of each monomer in Table 2 is the homopolymer of those monomer components. The glass transition temperature (T g) in units of C is shown, and T g on the right end of Table 3 is the glass transition temperature of each polymer.

At room temperature, an aqueous dispersion of the polymer shown in Table 3 and the colloidal sily force and polyolefin waxed purge ion shown in Tables 4 and 5 were mixed with a propeller stirrer at the composition ratios shown in Tables 7 to 12. The mixture was mixed with stirring using distilled water, and distilled water was added to adjust the solid content concentration. The solid content in the film shown in Tables 7 to 12 is 100 mass ⁰ / total of the polymer, silica and wax. Further, the amounts of silica and box in these tables are expressed in mass%. Table 2

Table 3

 Each S-form and its ratio in the polymer

 No. (a) (b) (c) (d) (e) (f) Tg Species Total Species%% Species »Amount%

A1 BA 25 BMA 30 55 AA 5 2HE A 5 St 10 AN 25 One-22

A2 BA 30 BMA 15 45 AA 2.5 2 HEMA 2.5 St 25 AN 25-one 24

A3 BA 45-0 45 MAA 2,5 2HE A 2.5 St 25 AN. 25--Ϊ0

A4 BA 49-0 49 AA 3 2HEMA 3 St 20 AN 25--3.7

A5 2EHA 25 BMA 22 47 MAA 3 HPMA 5 St 20 AN 25--10

A6 2EHA 25 BMA 22 47 MAA 4 2HEA 4 St 20 AN 25 1 9.4

A7 BA 45-0 45 AA 5 2HEMA 5 St 20 AN 25--9.0

A8 BA 58-0 58 AA 5 2HEMA 5 St 7 AN 25---9.2

A9 BA 38 BMA 35 73 AA 5 2HEMA 2 St 10 AN 10.0 1 0

A10 BA 20 BMA 31 51 AA 5 2 HEMA 5 St 14 AN 25.0 1 30

A1 1 BA 20 BMA 20 40 AA 5 2HE A 5 St 25 AN 25--37

A12 BA 45--45--2HE A 5 St 25 AN 25-One 8.9

A13 BA 45-0 45 AA 2 2HEMA 5 St 23 AN 25-8.9

A14 BA 45-0 45 AA 10 2 HEMA 5 St 15 AM 25-1 9, 2

A15 BA 45 ―-45 AA IS 2HE A 5 St 10 AN 25-9.4

A16 BA 38 BMA 22 60 AA 5-one St 20 AN 15 '-one 8.2

A17 BA 36 BMA 22 58 AA 5 2HE A 2 St 20 AN 15 11

ΑΪ8 BA 28 BMA 22 50 AA 5 2HEMA 10 St 20 AN 15--21

Α19 BA 23 BMA 22 45 AA 5 2HE A 15 St 20 AN 15--27

Α20 BA 30 BMA 40 70 AA 5 2HE A 5 One AN 20 ― One 8.2

Α21 BA 30 BMA 30 60 AA 5 2HEMA 5 St 10 AN 20-14

Α22 BA 30 BMA 10 40 AA 5 2HEMA 5 St 30 AN 20--27

Α23 BA 30 BMA 5 35 AA 5 2HEMA 5 St 35 AN 20--30

Α24 BA 50 BMA 20 70 AA 5 2HE A 5 St 20 ― ■ one ―--8.9

Α25 BA 40 BMA 20 60 AA 5 2HEMA 5 St 20 AN 10--5.0

Α26 BA 40 ― 0 40 AA 5 2HEMA 5 St 20 AN 30-― 17

Α27 BA 35 35 AA 5 2HEMA 5 St 20 AN 35 25

Α28 BA 40 BMA 6 46 AA 5 2HE A 5 St 20 AN 20 NMAAm 4 12

Α29 BA 34 BMA 6 40 AA 5 2HEMA 5 St 20 AN 20 NMAAm 10 21

Α30 BA 29 BMA 6 35 AA 5 2HEMA 5 St 20 AN 20 NMAAm 15 28

Α31 BA 42 BMA 5 47 MAA 2.5 2HEMA 2.5 St 20 AN 25GA 37.7

Α32 BA 35 BMA 5 40 MAA 2.5 2HEMA 2.5 St 20 AN 25 GMA- 10 9.1

Α33 BA 30 BMA 5 35 MAA 2.5 2 HEMA 2.5 St 20 AN 25 GMA 15 10.1

Α34 2EHA to 10 AA 10 2HEA 10 St 30 AN 30 GMA 10 37

Α35 2EHA 15 0 15 AA 10 2HEA 10 St 30 AN 25 GMA 10 25

Α36 BA 40 MMA 36 76 MAA 2 2HEMA 2 St 10 AN 10 19

Α37 BA 40 MMA 40 80 MAA 2 2HE A 2 St 10 AN 6 19 Table 4

 (5) Method of applying aqueous surface treatment agent to test plate

Each of the aqueous surface treating agents prepared above was applied to each of the test plates using a bar coater, and dried at an ambient temperature of 280 ° C. for 12 seconds. The plate temperature reached in this treatment was 130 ° C., and the target adhesion amount was 1. O g / m ² . The adhesion amount was adjusted by appropriately changing the solid concentration of the treating agent and the type of the percoater.

 (6) Performance test of surface-treated metal plate

 (a) Plane corrosion resistance

 According to the salt water fog test method described in JIS Z 2371, a 5% NaCl aqueous solution was sprayed on the surface-treated metal plate sample at an ambient temperature of 35 ° C, and the whitening rate after 72 hours was measured. . Based on the following evaluation criteria, the samples of ◎ and 〇 were judged to be good. The results are shown in Tables 7 to 12.

<Evaluation criteria> ◎: White area less than 5% of the total area

 〇: White area generation rate is 5% or more and less than 10% of the total area

 Δ: White area generation rate is 10% or more and less than 30% of the total area

 X: White area generation rate is 30% or more of the whole area

 (b) Corrosion resistance of processed part

 A 6 mm Erichsen process is applied to the surface-treated metal sheet sample, and a 5% aqueous NaCl solution is applied to the surface-treated metal sheet sample at an ambient temperature of 35 ° C according to the salt spray test method described in JIS Z 2371. , And the occurrence of white spots in the processed portion 48 hours later was measured. Based on the following evaluation criteria, the samples of ◎ and 〇 were judged as good. The results are shown in Tables 7 to 12.

<Evaluation criteria>

 ◎: White area ratio less than 5% of processed area

 ：: White area generation rate is 5% or more and less than 10% of the area of processed part

 △: White △ The occurrence area ratio is 10% or more and less than 30% of the processed area

 X: White area generation rate is 30% or more of processed area

 (c) Solvent resistance

 The surface of the surface-treated metal plate sample is impregnated with a solvent (ethanol or MEK) into gauze, and reciprocated 10 times with a load of 500 g. The appearance after sliding was observed, and the samples of ◎ and 〇 were judged as good according to the following evaluation criteria. The results are shown in Tables 7 to 12.

<Evaluation criteria>

 ◎: The swelling area of the film is less than 30% of the entire sliding part

 〇: The swelling area of the film is 30% or more of the entire sliding part

 Δ: Dissolution area of the film is less than 30% of the entire sliding part

 X: The dissolution area of the coating is 30% or more of the entire moving part.

 (d) Paint adhesion

Using a per coater, apply a melamine A resin coating (Amilac # 1000, manufactured by Kansai Paint Co., Ltd.) was applied to a dry film thickness of 25 μm and baked at a furnace temperature of 130 ° C for 20 minutes. Next, after leaving for 1 mm, the sample immersed in boiling water for 30 minutes and the sample not immersed were subjected to 7 mm Erichsen processing, and an adhesive tape (Nichipan Co., Ltd., Cellotape) was applied to the sample. Affixed to the processed part. The pressure-sensitive adhesive tape was immediately pulled obliquely at an angle of 45 °, and the appearance of the Ericssen processed portion was visually evaluated. Based on the following evaluation criteria, the samples of A and B were judged as good. The results are shown in Tables 7 to 12. Evaluation criteria>

 ◎ No peeling

 〇 Peeling area ratio 5% not dropped

 Δ Peeling area ratio 5% or more, 50. /. Less than

 X Peeling area ratio 50% or more

 (e) Press galling resistance

 A rectangular cylinder crank press test was performed on the surface-treated metal plate sample. The conditions for the square cylinder crank press test were as follows: a sample (0.8 x 220 x xi 80 mm) was formed to a size of 65 x 115 mm and a height of 50 mm at a wrinkle holding pressure of 6 tons, followed by forming. The rear sliding surface was visually evaluated. Based on the following evaluation criteria, the samples of A and B were judged as good. The results are shown in Tables 7-12.

 ◎: No blackening

 〇: Less than 50% of the sliding area is blackened, with sliding flaws

 △: 50% or more of the sliding area is blackened, with sliding flaws

 X.: Underlying metal is exposed and galling

 (f) Weldability

The surface-treated metal sheet sample was subjected to a continuous spot welding test under the conditions shown in Table 6 to determine the number of spots at which a nugget diameter of 3 mm or more could be formed stably. Was

 Table 6 Welding conditions

 Based on the following evaluation criteria, the samples of A and B were judged as good. Table of results? Shown in ~ 12.

 Evaluation criteria>

 ◎ Number of RBIs 5 0 0 0 or more

 〇 Number of hits 2 5 0 0 or more and less than 5 0 0 0

 △ Number of RBIs 1 0 0 0 or more and less than 250 0 0

X number of dots less than 1 0 0 0

Table 8

 Base treatment Solid composition in film Film performance

 Purple Treatment View Adhesion amount Polymer Silica Wax: Corrosion resistance Coating resistance Solvent resistance Freezing welding Remarks Method Type Kind Type Amount Flat part Addition part Adhesion EtOH Workability

36 EG mm Chromated 4D A36 B1 20 CI 5 1.0 ◎ © ◎ ◎ o ◎ ◎ The present invention

37 EG K E3-G 40 A37 B1 20 C1 5 1.0 ◎ ® ◎ Comparative example

38 Gl electrolysis black /-40 A7 B1 20 CI 5 1.0 o ◎ 0 ◎ ◎

39 Gl reaction black / block 40 A7 B1 20 C1 5 1.0 ◎ ◎ o ◎ 0 ◎ ◎

40 Gl coating Chromate 40 A7 B1 20 C1 5 1.0 ◎ o ◎ o ◎

41 2N Chromate 40 A7 B1 20 C1 5 1.0 ◎ © ◎ o The present invention

42 ZN reaction chromate 40 A7 B1 20 C1 5 1.0 ◎ ◎ ◎ o ◎ ◎

43 ZN coating Mate 40 A7 B1 20 CI 5 1.0 ◎ ◎ @ ◎ o ◎ ◎

44 EG reaction black / block 40 A10 B1 20 C1 5 1.0 ◎ o ◎ ◎ o The present invention

45 EG coating Cloth 40 A10 B1 20 c \ 5 1.0 ◎ o ◎ o ◎ ◎

46 EG digestion chromate 40 A21 Βί 20 G1 5 1.0 ◎ ◎ ◎ o ◎ The present invention

47 EG electrolysis black / piece 40 A21 Β2 20 ci 5 1.0 © ◎ ◎ o ◎ ◎

48 EG solution close 40 A21 81 0 C1 5 1.0 ◎ ◎ o ◎ Comparative example

49 EG resolution black / -to 40 A21 Β1 10 C1 5 1.0 © © ◎ ◎ o ◎

50 EG mm Mate 40 A2) Β1 · 25 C1 5 1.0 ◎ ◎ ◎ ◎ o ◎ The present invention

51 EG digest clot 40 A21 Β1 30 CI 5 1.0 ◎ ◎ ◎ ◎ o ◎ ◎

52 EG electrolytic blackCI 5 1

 CO 40 A21 81 35.0 ◎ o ◎ ◎ o ◎ The present invention

 53 EG disassembly 40 A21 Β1 40 C1 5 1.0 o o ◎ o © ◎ Comparative example

54 EG digestion chromate 40 A25 Β1 20 Gl 5 0.1 Δ o o m ◎ Comparative example

55 EG electrolytic coating α-mate 40 A25 Β1 20 C1 5 0.2 o m ◎ ◎ o ◎ ◎

56 EG electrolysis black / white 40 A25 Β1 20 C1 5 3.0 ◎ ◎ ◎ o ◎ ◎ The present invention

57 EG compress chromate 40 A25 Β1 20 C1 5 5.0 ◎ ◎ o o o o The present invention

58 EG resolution black / "g 40 A25 Β1 20 CI 5 8.0 ◎ o o ◎ Comparative example

59 EG mm Chromate 40 A31 Β1 20 ― 1.0 1.0 ◎ ◎ ◎ o o ◎ The present invention

60 EG digestion chromate 40 A31 Bt 20 CI 0.1 1.0 ◎ ◎ ◎ ◎ o ◎

61 EG electrolytic chromate 40 A31 B1 20 C1 1 1.0 ◎ ◎ ◎ o ◎ ◎

62 EG digest 40 A31 B1 20 C1 10 1.0 ◎ ◎ ◎ ◎ o ◎ ◎

63 EG m Chromate 40 A31 B1 20 C1 35 1.0 ◎ o o ◎ o ◎ ◎

64 EG mm Mate 40 A31 B1 20 C1 40 1.0 o o m o o ◎ ◎ The present invention

65 EG Electrolytic cloth 40 A31 B1 20 C2 0.1 1.0 ◎ ◎ ◎ ◎ o ◎

66 EG Chromate 40 A31 B1 20 C2 1 1.0 ◎ ◎ ◎ ◎ o ◎ ◎

67 EG Dragon Chromate 40 A31 B1 20 C2 10 1.0 ◎ © ◎ ◎ o ◎ ◎ The present invention

68 EG digestion chromate 40 A31 B1 20 C2 35 f.O ◎ o o ◎ o ◎ ◎

69 EG Electrolytic Cloth 40 A31 B1 20 C2 40 1.0 o o m o o ◎ ◎

70 EG electrolytic black /-40 A31 81 20 C3 0.1 1.0 ◎ ◎ ◎ o ◎ ◎

71 EG Mate 40 A31 81 20 C3 1 1.0 '◎ ◎ ◎ o ◎ ◎ The present invention

72 EG digestion black 40 A31 Βΐ 20 C3 10 1.0 ◎ ◎ ◎ o ◎ ◎ The present invention

73 EG chromate 40 A31 Β1 20 C3 35 1.0 ◎ o o ◎ o ◎ ◎

74 EG electrolysis chromate 40 A31 Β1 20 C3 40 1.0 oo oo ◎ ◎

Table 9

Table 10 Base treatment g3 Solid composition in coating

 No.Material treatment ^ Adhesion amount.Polymer silica wax adhered

 98 EG Electrolytic Cloth 40 Α1 Β1 20 C3 5 1.0 ◎ ◎ ◎ ◎ 0 ◎ ◎

99 EG electrolysis cloth 40 Α2 Β1 20 C3 5 1.0 ◎ ◎ ◎ ◎ o ◎ ◎ The present invention

1 00 EG electrolytic chromate 40 A3 Β1 20 C3 5 1.0 ◎ ◎ © ◎ 0 ◎ ◎

101 EG electrolysis cell 40 Α4 Β1 20 C3 5 1.0 ◎ ◎ ◎ ◎ o ◎ ◎ The present invention

1 02 EG electrolytic chromate 40 Α5 Β1 20 C3 5 1.0 ◎ ◎ © o © ® The present invention

103 EG electrolysis α-meter 40 Α6 Β1 20 C3 5 1.0 ◎ ◎ ◎ o © ◎

104 EG electrolytic chromate 40 Α7 Β1 20 C3 5 1.0 ◎ ◎ ◎ ◎ o © ◎

105 EG electrolysis ゥ 0 drop 40 Α9 Β1 20 C3 5 1.0 ◎ ◎ ◎ ® o © ◎ The present invention

106 EG electrolysis, chromate 40 Α10 Β1 20 C3 5 1.0 ◎ o © o ◎ ◎

CO 107 EG Electrolytic Cloth 40 Α13 Β1 20 C3 5 1.0 ® ◎ ◎ o ◎ The present invention

 108 EG electrolytic chromate 40 Α14 B1 20 C3 5 1.0 o o ◎ ◎ o ◎ ◎ The present invention

109 EG Electrolytic Cloth 40 Α17 Β1 20 03 5 1.0 © ◎ ◎ ◎ o ◎ ® The present invention

1 10 EG Electrolytic chromate 40 Α 8 Β1 20 C3 5 1.0 o o ◎ 0 ◎ ® The present invention

1 1 1 EG electrolysis chromate 40 Α21 Β1 20 C3 5 1.0 © ◎ ◎ ◎ o ◎ ◎

1 12 EG Lightning Chromate 40 Α22 Β1 20 G3 5 1.0 ◎ © ◎ ® o ◎ ® The present invention

1 13 EG electrolytic chromate 40 Α25 Β1 20 C3 5 1.0 ◎ ◎ o ◎ The present invention

1 14 EG Electrolytic Cloth 40 Α26 Β1 20 C3 5 1.0 o o ◎ ◎ o ◎ The present invention

1 1 5 EG Cleavage black /-40 40 Α28 Β1 20 C3 5 1.0 o o © © ® ◎ ◎ The present invention

116 EG electrolytic chromate 40 Α29 B1 20 C3 5 1.0 o o ◎ ◎ ◎

1 17 EG Lightning close 40 Α31 Β1 20 C3 5 1.0 ◎ ◎ ◎ ◎ o ◎ ◎

1 18 EG electrolysis chromate 40 Α32 Β1 20 C3.5.5 1.0 ◎ ◎ ◎ ® 0 ◎ ® The present invention

1 19 EG electrolytic chromate 40 Α35 Β1 • 20 C3 5 1.0 ◎ ◎ ◎ © o ◎ ◎

120 EG electrolytic chromate 40 Α36 Β1 20 C3 5 1.0 ◎ ◎ © ◎ o ◎ ◎ The present invention

Table 11

1 2

 Base treatment Solid composition in film Film performance

Processing Type Adhesion: 2 Polymerized silica wax vimM! Corrosion resistance Coating New solvent resistance Press welding method Type Type 1 Quantity Type S Flat part 1 Machining Adhesion Workability Electrolytic mate ¹ ® © © @ o @ © mei electrolytic electrolytic ¹ l 〇 o © o @ Invention electrolytic chromate ¹ @ © © ◎ o © ® Electrolyte sheet of the present invention oo @ ◎ o © ® Electrolyte chronoute ¹ © ◎ © @ o © ® Electrolyte chromate of the present invention ◎ o © Electrolyte 発 明 of the present invention. Mate ◎ © @ @ o @ ® Invention electrolytic chromate oo ® © o @ ® Invention mm chromate oo © ◎ ◎ @ Invention electrolytic chromate oo @ ◎ © ® ® Invention electrolytic chromate ¹ © @ © © o © ® Invention Invention Electrolytic Chromate ¹ © ◎ ◎ o © Invention Electrolysis Chromate ◎ © ◎ o ® ® Invention Electrolysis Chromate © © ◎ o ® ® Invention Electrolysis Chromate @ © ◎ o ® © Invention t Electrolysis © © © @ o ® ◎ The present invention electrolytic chromate 40 © © © o © © The present invention electrolytic chromate ◎ @ © © o ® ◎ The present invention

171 Electrolytic chromate 1 ◎ © © @ o ® © The present invention electrolytic chromate © @ © o © ◎ The present invention electrolytic chromate ◎ ◎ © ◎ o ® The present invention electrolytic chromate © © @ © o © ◎ The present invention electrolytic chromate © o @ ◎ o © ® Electrolytic chromate of the present invention ¹ ◎ © © ◎ o © © mm chromate of the present invention oo @ ◎ o ® © Electrolytic chromate of the present invention © ◎ © ◎ o ® ◎ Present invention / y Electrolytic chromate 40 too @ © o © ©

Electrolytic chromate © © ◎ ◎ o © © Electrolytic chromate of the present invention © © ◎ ◎ o ◎ Electrolytic chromate of the present invention © • @ ◎ o ◎ © Electrolytic chromate of the present invention oo © ◎ o © ◎ Electrolytic chromate of the present invention oo © ◎ @ ® The present invention electrolytic chromate o © © @ © The present invention chroma © ◎ ◎ o ◎ © The present invention electrolytic chromate ◎ © o ® The present invention electrolytic chromate ◎ © © © o ® © The present invention. Mate ◎ ◎ @ @ o © 1 Invention

As can be seen from Tables 7 to 12, the surface-treated metal sheets obtained by the surface treatment method of the present invention are not only corrosion-resistant in flat areas, solvent resistance, topcoat coatability and weldability, but also in the corrosion resistance in the processed areas. It is clear that the film has excellent scratch resistance. Industrial applicability

 The surface-treated metal sheet of the present invention has excellent corrosion resistance and scratch resistance as well as flat portion corrosion resistance, solvent resistance, top coat coatability, and weldability, and is therefore suitable for the household appliances, building materials, and automotive fields. It is suitable as a material and has extremely high industrial utility value. In addition, the aqueous surface treatment agent and the method for producing a surface-treated metal sheet of the present invention provide a surface-treated metal sheet having excellent corrosion resistance in a flat portion, solvent resistance, overcoating property, weldability, corrosion resistance in a processed portion, and scratch resistance. Can be provided to the market.

Claims

The scope of the claims

1. The acryl resin contains 5 to 35% by mass of colloidal silica in terms of water and solid content, and the acryl resin is represented by the following general formula (1): R ¹

 I

H ₂ C = C—— C00R ² … (1)

(In the formula, R ¹ is hydrogen or a methyl group, and R ² is a straight-chain or branched alkyl group having 1 to 8 carbon atoms.)

And (b) 2 to 10% by mass of α,] 3-ethylene having a carboxyl group in the molecule. and sex unsaturated monomer, 2-1 0 weight _^0/0 Nohi which have a hydroxyl group in (c) molecules, - an ethylenically unsaturated monomer, (d) 1 0~ 3 0 wt% A mixture of styrene, (e) 10 to 30% by mass of acrylonitrile, and (f) 0 to 10% by mass of an unsaturated monomer copolymerizable with these monomers. An aqueous surface treating agent which is a polymer obtained by a polymerization reaction and has a glass transition temperature of 0 to 30 ° C.

 2. (f) Force in the acrylic resin It must contain an unsaturated monomer having one or more functional groups selected from glycidyl, aziridinyl, methylol and silanol groups in the molecule. The aqueous surface treating agent according to claim 1, wherein:

 3. The aqueous surface treatment according to claim 1, wherein the aqueous surface treatment agent further contains 35% by mass or less of a polyolefin wax dispersion in terms of a solid content. Agent.

4. Acrylic resin and solid content conversion of 5 to 35 on the plated metal plate The organic resin has an organic-inorganic composite film containing 0.3 to 5.0 g / m ² having a mass of 0.2% by weight, and the acrylic resin is represented by the following formula (1):

R ¹

H ₂ G ^: C00R '(1)

(In the formula, R ¹ is hydrogen or a methyl group, and R ² is a linear or branched alkyl group having 1 to 8 carbon atoms.)

Indicated by 15-76 mass ⁰ /. And (b) 2 to 10% by mass of a,] 3-ethylenically unsaturated monomer having a carboxyl group in the molecule, and (c) a from 2 to 1 0 weight _^0/0 to have a hydroxyl group in the molecule, j8 - ethylenically unsaturated monomer, and (d) 1 0~ 3 0 mass _^0/0 of styrene, (e) 1 0 To 30% by mass of acrylonitrile and (f) a polymer obtained by a polymerization reaction of 0 to 10% by mass of an unsaturated monomer copolymerizable with these monomers. A surface-treated metal material which is united and has a glass transition temperature of 0 to 30 ° C.

 5. Unsaturated monomer having at least one kind of functional group in the molecule, wherein (f) constituting the acrylic resin is selected from the group consisting of glycidyl group, aziridinyl group, methylol group and silanol group 5. The surface-treated metal material according to claim 4, comprising:

 6. The method according to claim 4, wherein the organic-inorganic composite film further contains 35% by mass or less of a polyolefin dispersion in terms of solid content mass. Surface treated metal material.

7. The aqueous surface treating agent according to any one of claims 1 to 3 on a plated metal plate or a plated metal plate that has been subjected to a base treatment, in an amount of 0.3 to 5. 0 g / m ² was coated, Mu organic was dried For producing surface-treated metal material characterized by forming composite film