JP2000218230A - Surface treatment of galvanized steel sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a galvanized steel sheet excellent in adhesion by treating the surface of a galvanized steel sheet with an aqueous solution prepared by using an acrylic copolymer obtained by polymerizing acrylic monomers containing a prescribed functional group in the presence of a reactive emulsifier and colloidal silica as principal components. SOLUTION: A galvanized steel sheet is treated with an aqueous solution containing (A) 10-99 wt.% fine particles of an acrylic copolymer obtained by emulsion-polymerizing acrylic monomers containing a radical polymerizable unsaturated group in the presence of a reactive emulsifier, (B) 0-50 wt.% fine particles of a urethane resin, (C) 0-40 wt.% fine particles of an olefin copolymer and (D) 1-40 wt.% fine particles of colloidal silica. The treated steel sheet is dried to form 0.3-2 g/m3 coating film and the objective galvanized steel sheet excellent in corrosion resistance and adhesion of coating materials is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface-treated steel sheet mainly used for home appliances, which does not contain any harmful hexavalent chromium on the steel sheet and which is used in a manufacturing process.
The present invention relates to a galvanized steel sheet which has no emission of chromium (VI) and has the same corrosion resistance and paint adhesion as a conventional chromate-treated steel sheet containing hexavalent chromium.

[0002]

2. Description of the Related Art Zinc-based plated steel sheets are widely used as steel sheets for home appliances, building materials and automobiles from the viewpoint of corrosion resistance.
However, zinc alone is not sufficient in terms of corrosion resistance and the appearance deteriorates due to the generation of white rust.In addition, when used as a coating base, adhesion to paint cannot be ensured, so chromate treatment and zinc phosphate treatment are usually used. Done. In the case of the chromate treatment, the function of suppressing white rust is great, but the adhesion to the paint is not always sufficient. In addition, there is a problem that a large amount of harmful hexavalent chromium is contained. On the other hand, in the case of zinc phosphate treatment, the adhesion with the paint is relatively good, but the white rust suppression function when used naked is extremely weak,
Therefore, the sealing treatment is performed with a treatment liquid containing harmful hexavalent chromium as in the case of the normal chromate treatment. A steel sheet in which a chromate layer is formed as a first layer on a zinc-based plating, and an organic coating is further provided on the chromate layer is also known. in this case,
Although there is no elution of hexavalent chromium, the content is not zero due to the chromate treatment. Further, in the manufacturing process, hexavalent chromium is inevitably discharged, so it is still environmentally unfavorable. . In order to solve these problems, it has been proposed to dispose the chromate layer and provide an organic coating layer directly on the zinc-based plating. For example, JP
-92846 proposes formation of an organic-inorganic composite film of an organic resin, a silane coupling agent and silica. Japanese Patent Application Laid-Open No. Hei 6-316685 proposes that fine particles of a copolymer of methyl methacrylate, styrene, and a crosslinkable monomer be used to form a film directly on zinc-based plating. Further, Japanese Patent Application Laid-Open No. 9-221595 proposes a treatment on zinc-based plating with a carbodiimide bond-containing resin. In each of the above examples, a relatively good corrosion resistance can be ensured by increasing the film thickness.However, when trying to obtain the same corrosion resistance as that of the chromate treatment, the film thickness becomes extremely thick, which is uneconomical. At the same time, problems such as welding and processing also occur. Furthermore, when used as a coating base, the adhesion between the top coat and the top coat is good, but there is no chromate layer or zinc phosphate layer that mediates the adhesion between the zinc and the film, There is a problem that the adhesion is extremely poor, and in particular, the water resistance cannot be secured at all. JP 5-
200357 discloses a method of forming a resin coating film of a two-component reaction type epoxy resin containing an epoxy silane coupling agent on a zinc plating, but also in this case, a method of forming a resin coating between the zinc plating and the resin coating film is disclosed. Does not have sufficient adhesion in a water-resistant environment, and requires a thick film of about 80μ to ensure corrosion resistance. Such a thick film has problems in weldability and workability, and is not suitable as a general-purpose steel sheet for home appliances. In the case of zinc, the affinity of the metal surface with water or oxygen is greater than that of a metal such as iron, so even if the resin is directly adhered to the zinc surface, for example, in a water-resistant environment, water It is considered that the dissociative adsorption bond easily replaces the bond between zinc and the resin, so that it is difficult to secure adhesion. To improve this problem, see, for example,
No. 8248 discloses a method of forming a lithium silicate layer on a zinc-based plating layer, and further forming an organic-inorganic composite film on the lithium silicate layer. Even in this case, the performance is not always sufficient, and the processing is performed in two layers, which is disadvantageous in cost and process.

[0003]

SUMMARY OF THE INVENTION The object of the present invention is to solve the above-mentioned drawbacks and to provide a zinc-based plated steel sheet which is excellent in corrosion resistance (white rust resistance) and adhesion by one layer treatment without chromate treatment. With the goal.

The inventors of the present invention have conducted various studies to solve the above problems, and as a result, have found that an acrylic copolymer obtained by polymerizing an acrylic monomer having a predetermined functional group in the presence of a reactive emulsifier and colloidal silica It has been found that if the surface of a zinc-based plated steel sheet is treated with an aqueous solution adjusted to contain Zn as a main component, a water-resistant and stable bond can be formed at the interface between Zn and the film, and the above-mentioned problems can be solved.

[0005]

The gist of the present invention is as follows: (1) The following (A) to (D), wherein the total of (A) to (D) is 100% by weight. 10 to 99% by weight of acrylic copolymer fine particles (active ingredient) obtained by emulsion polymerization of monomers (a) to (e) in the presence of a reactive emulsifier having a radically polymerizable unsaturated group in the molecule (A) 30 to 98.4% by weight of a (meth) acrylic acid ester monomer represented by the following general formula (1), and (b) 0.5 of an α, β-ethylenically unsaturated monomer having a carboxyl group in the molecule. ~
10% by weight, (c) 1 to 20% by weight of α, β-ethylenically unsaturated monomer having a glycidyl group in the molecule, (d) α, β-ethylenically unsaturated monomer having an alkoxysilane group in the molecule Monomer 0.1 ~
10% by weight, (e) 0 to 30% by weight of monomers other than (a) to (d) copolymerizable with (a) to (d) above, provided that the total of (a) to (e) 1
00% by weight]

[0006]

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Wherein R ¹ is hydrogen or a methyl group, and R ² is a linear or branched alkyl group having 1 to 12 carbon atoms. (B) Urethane resin fine particles (active ingredient): 0 to 50% by weight;
Zinc-based coated steel sheet is prepared with an aqueous solution containing (C) olefin copolymer fine particles (active ingredient) 0 to 40% by weight and (D) colloidal silica fine particles (active ingredient) 1 to 40% by weight as essential components. treatment, and dried without washing 0.3 to 2 g / m ²
Surface treatment method for galvanized steel sheet characterized by forming a film of. (2) The surface treatment method for a galvanized steel sheet according to the preceding paragraph, wherein the average particle diameter of the colloidal fine particles having anionic or nonionic properties is less than 150 nm. (3) The method for treating a surface of a galvanized steel sheet according to any one of the preceding items, further comprising treating with an aqueous solution containing 1 to 10% by weight of fine particles of a wax component. (4) In any one of the preceding items, the solid content concentration of the aqueous solution is 5 to
A surface treatment method for a zinc-based plated steel sheet, characterized in that the sheet is dried at a temperature rise rate of 10 ° C./sec or more to reach a plate temperature of 80 to 200 ° C. at 25% by weight. It is.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

In the present invention, a zinc-coated steel sheet refers to pure Z
n-plated steel plate, or Zn and Fe, Ni, Co, C
r, etc., or an alloy-plated steel sheet, or a dispersion-plated steel sheet in which various organic and inorganic substances are further dispersed. As the plating method, any of electroplating, immersion in a molten bath, vapor deposition and the like can be used.

The acrylic copolymer fine particles used in the aqueous solution for treating the zinc-based plated steel sheet are a (meth) acrylate monomer represented by the general formula (1).
(a), α, β-ethylenically unsaturated monomer having a carboxyl group in the molecule (b), α, β-ethylenically unsaturated monomer having a glycidyl group in the molecule (c), intramolecular Α, β-ethylenically unsaturated monomer (d) having an alkoxysilane group to the above (a) to (d) copolymerizable with (a) to (d) other monomers (e) It is obtained by emulsion polymerization in the presence of a reactive emulsifier having a radically polymerizable unsaturated group in the molecule. As the (meth) acrylate monomer (a), for example, methyl acrylate, ethyl acrylate, n-butyl acrylate,
i-butyl acrylate, n-octyl acrylate, i-octyl acrylate, 2-ethylhexyl acrylate,
C1-C12 linear or branched alkyl esters of acrylic acid such as n-nonyl acrylate, i-nonyl acrylate, n-decyl acrylate and n-dodecyl acrylate; for example, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate Linear or branched alkyl esters of methacrylic acid having 1 to 12 carbon atoms, such as, 2-ethylhexyl methacrylate and n-dodecyl methacrylate;

The above (meth) acrylate monomer (a)
Is used in an amount of 30 to 9 in a total of 100% by weight of the monomers (a) to (e).
8.4% by weight, preferably 50-96% by weight, particularly preferably 6%
It is preferably from 5 to 92% by weight. When the amount of the monomer (a) used is too small as less than the lower limit, when the obtained coating composition is used for undercoating of a zinc-based plated steel sheet (hereinafter, referred to as a base material), a topcoat paint to be applied repeatedly. This is not preferred because the adhesion to the resin may decrease. On the other hand, if the amount exceeds the upper limit and is too large, when the obtained coating composition is used for coating a metal substrate such as a steel sheet, the substrate adhesion deteriorates and the white rust resistance is reduced, which is preferable. Absent.

Α, having a carboxyl group in the molecule
The β-ethylenically unsaturated monomer (b) includes one or more carboxylic acids in the molecule, for example,
Acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, crotonic acid, itaconic acid, citraconic acid, cinnamic acid, (meth) acrylic acid dimer, ω-carboxy-polycaprolactone mono (meth) acrylate, succinic mono Hydroxyethyl (meth) acrylate, monohydroxyethyl (meth) acrylate maleate, monohydroxyethyl (meth) acrylate fumarate, monohydroxyethyl (meth) acrylate phthalate, 1,2-dicarboxycyclohexane monohydroxyethyl (meth) Acrylate and the like can be suitably used.

The amount of the monomer (b) used is
It is 0.5 to 10% by weight, preferably 1 to 7% by weight, in the total of 100% by weight of (a) to (e). If the amount of the monomer (b) is too small, less than the lower limit, the adhesion of the obtained coating composition coating film to the substrate tends to decrease, such being undesirable. On the other hand, if the amount exceeds the upper limit, the alkali resistance of the coating film,
Performance such as white rust resistance tends to decrease, which is not preferable.

The above α, having a glycidyl group in the molecule,
As the β-ethylenically unsaturated monomer (c), for example, glycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, glycidyl vinyl ether, 3,4-epoxycyclohexyl vinyl ether, glycidyl (meth) Allyl ether, 3,4-epoxycyclohexyl (meth) allyl ether and the like can be mentioned.

The amount of the monomer (c) used is from the monomers (a) to
(e) 1 to 20% by weight, preferably 1 to 100% by weight in total
It is 15% by weight, more preferably 2 to 12% by weight. If the amount is too small, less than the lower limit, the effect of imparting adhesion to the substrate of the coating composition obtained is insufficient, and the white rust resistance is also insufficient. on the other hand,
If the amount exceeds the upper limit and is too large, the film forming property of the obtained aqueous coating composition tends to decrease, which is not preferable.

The α, β-ethylenically unsaturated monomer (d) having an alkoxysilane group in the molecule is preferably a hydrolyzable monomer such as vinyltrimethoxysilane or vinyltriethoxysilane. , Vinyl tris (2
-Methoxy-ethoxy) silane, vinyltriacetoxysilane, 3-methacryloxypropyltrimethoxysilane, vinyltrichlorosilane, 3-methacryloxypropyltris (methoxy-ethoxy) silane and the like. Among them, 3-methacryloxypropyltrimethoxysilane can be particularly preferably used.

These monomers (d) can be used in the range of 0.1 to 10% by weight based on 100% by weight of the total of the monomers (a) to (e). When considering the balance between the effect of imparting adhesion of the film to the substrate and the adverse effect on other coating properties such as alkali resistance, the amount is preferably used in the range of 0.5 to 10% by weight.

The above monomer (e), that is, the above (a) to (d)
Examples of the monomers other than (a) to (d) copolymerizable with, for example, styrene, α-methylstyrene, t-butylstyrene, p-chlorostyrene, chloromethylstyrene, aromatic monovinyl monomers such as vinyltoluene; Vinyl cyanide monomers such as acrylonitrile and methacrylonitrile; examples thereof include vinyl formate, vinyl acetate, vinyl propionate, and “vinyl versatate”. These monomers (e) are usually used for the purpose of improving the water resistance, alkali resistance, solvent resistance, etc. of the obtained aqueous coating composition coating film, and the copolymerization amount is a single amount. In general, the amount is preferably in the range of 0 to 30% by weight based on 100% by weight of the total of the bodies (a) to (e).

The aqueous acrylic copolymer dispersion used in the present invention is prepared by adding the above-mentioned monomers (a) to (e) to a reactive emulsifier having a radical polymerizable unsaturated group in the molecule. Is obtained by emulsion polymerization in the presence of

The reactive emulsifier used in the present invention is not particularly limited, either anionic or nonionic emulsifiers. For example, radical emulsifiers such as (meth) allyl group, (meth) acryl group and styryl group are used. Emulsifiers having an unsaturated group can be used alone or in combination of two or more.

Examples of such anionic reactive emulsifiers include reactive emulsifiers represented by the following general formulas (2), (3), (4) and (5).

[0022]

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[0023]

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[0024]

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[0025]

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Wherein R ¹ is hydrogen or methyl, R ³ and R ⁵ are alkyl, alkenyl, aryl or aralkyl having 6 to 18 carbon atoms, R ⁴ is hydrogen or methyl,
EO is -CH ₂ CH ₂ O-, X ¹ is a single bond or a methylene group, M represents an alkali metal, ammonium or organic ammonium, m and n are natural numbers of 1 to 50, q is 0 or 1]

Specific examples of the anionic reactive emulsifier represented by the above general formula (2) include, for example, "Adecaria Soap SE-10N", "Adecaria Soap SE-20N", and "Adecaria Soap SE-30N". [As above, manufactured by Asahi Denka Kogyo Co., Ltd.]; specific examples of the anionic reactive emulsifier represented by the general formula (3) include, for example, "Aqualon HS-05", "Aqualon HS-10", Aqualon HS-20, Aqualon HS-3
0 "(above, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.);
Specific examples of the anionic reactive emulsifier of, for example,
`` Latemur S-120 '', `` Latemur S-120A '', `` Latemur S
-180 '', `` Latemul S-180A '' (all manufactured by Kao Corporation),
Specific examples of the anionic reactive emulsifier of the general formula (5) include “Entox MS-60” [Nippon Emulsifier Co., Ltd.] )) And the like;

Other anionic reactive emulsifiers include, for example, alkyl alkenyl succinate-based reactive emulsifiers such as "Latemul ASK" (manufactured by Kao Corporation);
For example, "Eleminor RS-30" (manufactured by Sanyo Chemical Industries, Ltd.)
Polyoxyalkylene (meth) acrylate sulfate ester-based reactive emulsifiers such as "RA-1120" and "RA-261"
Polyoxalkylene alkyl ether fatty acid unsaturated dicarboxylic acid ester-based reactive emulsifiers such as 4 "[all manufactured by Nippon Emulsifier Co., Ltd.]; for example," Antox MS-2N "
(Nippon Emulsifier Co., Ltd.) and the like (meth) acrylic acid sulfoalkyl ester salt-based reactive emulsifier; dihydroxyalkyl (meth) acrylate sulfate ester-based reactive emulsifier; for example, "H-3330PL" [Daiichi Kogyo Mono or di (glycerol-1-alkylphenyl-3-)
(Allyl-2-polyoxyalkylene ether) phosphate ester-based reactive emulsifier;

Examples of the nonionic reactive emulsifier that can be used in the present invention include the following general formulas (6) and (7):
And a reactive emulsifier represented by the following formula:

[0030]

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[0031]

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Wherein R ¹ is hydrogen or methyl, R ³ is alkyl, alkenyl, aryl or aralkyl having 6 to 18 carbon atoms, R ⁴ is hydrogen or methyl, and EO is —
CH ₂ CH ₂ O—, X ¹ is a single bond or a methylene group, m is 1
Is a natural number of ~ 50)

Specific examples of the nonionic reactive emulsifier represented by the general formula (6) include, for example, "Adecaria soap".
NE-10 "," Adecaria soap NE-20 "," Adecaria soap NE-30 "(all manufactured by Asahi Denka Kogyo Co., Ltd.) and the like; a nonionic reactive emulsifier represented by the above general formula (7) Specific examples of "Aqualon RN-10", "Aquaron RN-
20 "," AQUALON RN-30 "," AQUALON RN-50 "(both manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) and the like.

Other nonionic reactive emulsifiers include, for example, polyoxyalkylene alkyl phenyl ether (meth) acrylates such as "RMA-564" and "RMA-568" (both manufactured by Nippon Emulsifier Co., Ltd.). And a polyoxyalkylene alkylphenyl ether (meth) acrylate-based reactive emulsifier such as "RMA-114" (manufactured by Nippon Emulsifier Co., Ltd.). Of these reactive emulsifiers, it is preferable to use an anionic reactive emulsifier as an essential component because, for example, a small particle size suitable as an acrylic copolymer aqueous dispersion used in the present invention is easily obtained. Desirably, the monomer (a) used in the present invention is excellent in copolymerizability with (e), less likely to remain unreacted even when used in large amounts, the resulting aqueous coating composition coating film The glycerol-1-allyl-3-alkylphenyl-2-polyoxyethylene sulfate-based anionic reactivity represented by the above general formula (2) because it does not hinder the performance such as corrosion resistance of glycerol It is particularly preferable to use an emulsifier or a polyoxyethylene alkyl alkenyl phenyl ether sulfate ester type anionic reactive emulsifier represented by the general formula (3).

The amount of the reactive emulsifier to be used is generally 0.1 to 30 parts by weight per 100 parts by weight of the total of the essential monomers (a) to (e) constituting the acrylic copolymer in the present invention. It is preferably used in the range of 2 to 25 parts by weight, particularly preferably 3 to 20 parts by weight.

In the emulsion polymerization of the acrylic copolymer aqueous dispersion used in the present invention, the above-mentioned reactivity may be selected so long as it does not adversely affect the performance of the resulting copolymer aqueous dispersion and aqueous coating composition. If necessary, a usual anionic and / or nonionic emulsifier can be used together with the emulsifier.

In the emulsion polymerization, usually, for example,
Initiation of polymerization of persulfates such as sodium persulfate, potassium persulfate and ammonium persulfate; organic peroxides such as t-butyl hydroperoxide, cumene hydroperoxide and p-menthane hydroperoxide; hydrogen peroxide; Agent is used. These polymerization initiators can be used in either one kind or a combination of plural kinds. These polymerization initiators are preferably used in an amount of about 0.1 to 1 part by weight based on 100 parts by weight of the total of the monomers (a) to (e).

In the emulsion polymerization, a reducing agent can be used together with the polymerization initiator, if desired. Examples of such a reducing agent include reducing organic compounds such as ascorbic acid, tartaric acid, citric acid, glucose, and formaldehyde sulfoxylate metal salt; sodium thiosulfate, sodium sulfite, sodium bisulfite, sodium metabisulfite, and the like. And a reducing inorganic compound.
These reducing agents are preferably used in an amount of about 0.1 to 1 part by weight based on 100 parts by weight of the total of the monomers (a) to (e).

Furthermore, a chain transfer agent can be used in the emulsion polymerization. Examples of such a chain transfer agent include n-dodecyl mercaptan, t-dodecyl mercaptan, n-butyl mercaptan, 2-ethylhexyl thioglycolate, 2-mercaptoethanol, and trichlorobromomethane. These chain transfer agents are used in an amount of 0 to 100 parts by weight in total of the monomers (a) to (e).
It is preferred to use an amount of about 1 part by weight.

The copolymerization temperature preferably employed in the emulsion copolymerization of the acrylic copolymer used in the present invention is from about 40 to
100 ° C., especially about 60-90 ° C.

The average particle size of the copolymer fine particles dispersed in the aqueous medium of the thus-obtained acrylic copolymer aqueous dispersion is generally 100 nm or less, particularly preferably 10 to 80 nm.

The pH of the aqueous dispersion of an acrylic copolymer used in the present invention, which can be obtained as described above, may be adjusted with ammonia water, an amine or the like, if necessary.

The treatment liquid of the present invention contains colloidal silica fine particles as an essential component together with the above-mentioned acrylic copolymer fine particles. The amount of colloidal silica needs to be 1 to 40% by weight. If the amount is less than the lower limit, the adhesion to the plating surface is insufficient and the white rust resistance is poor. And the film becomes brittle, so that the white rust resistance of the processed portion is deteriorated. As the type of colloidal silica, those having anionic or nonionic properties and having an average particle diameter of less than 150 nm are preferable from the viewpoint of further improving white rust resistance. By using such colloidal silica, the formed film becomes more dense and the white rust resistance can be improved.

The aqueous coating composition used in the present invention preferably contains urethane-based resin fine particles and olefin-based copolymer fine particles in addition to the above-mentioned acrylic copolymer fine particles and colloidal silica fine particles. By including these in the aqueous coating composition, when the composition is used as a metal undercoat, the adhesion to the metal base is significantly improved, and the base of the coating at the time of forming the resulting coated metal plate is obtained. Since the followability is improved, especially the corrosion resistance of the molded portion is improved, and the adhesion to the top coat is also improved.

Such a urethane-based resin is prepared by reacting a chain extender with a urethane prepolymer having an isocyanate group at a terminal obtained by reacting a polyisocyanate compound with a polyol compound according to a usual method. can do.

Examples of the above polyisocyanate compound include 1,3- or 1,4-phenylene diisocyanate, 2,4- or 2,6-tolylene diisocyanate, 1,5-naphthylene diisocyanate, and 4,4 ′ -Diphenylmethane diisocyanate, 3,3'-dimethyldiphenylmethane-4,4 '
Aromatic polyisocyanate compounds such as -diisocyanate and 1,3-xylylene diisocyanate; for example, 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, 2,2,4-trimethyl-1,6-hexamethylene Aliphatic polyisocyanate compounds such as diisocyanate, 1,8-octamethylene diisocyanate, 1,10-decamethylene diisocyanate; for example, 1,3- or 1,4-cyclohexylene diisocyanate, 1-methylcyclohexane-1,3- or Alicyclic polyisocyanate compounds such as 1,4-diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate, and 1,3-isocyanomethylcyclohexane;

Examples of the polyol compound which can be reacted with the above-mentioned polyisocyanate compound include polyester polyols, polyether polyols, polyester ether polyols, and polycarbonate polyols.

Examples of the polyester polyols include ethylene glycol, propylene glycol, 1,4-
Butanediol, 1,6-hexanediol, glycerol, trimethylolpropane, pentaerythritol,
Sorbitan, polyhydric alcohols such as sorbitol, and, for example, succinic acid, adipic acid, sebacic acid, maleic acid,
Condensates with polycarboxylic acids such as fumaric acid, mesaconic acid, citraconic acid, itaconic acid, glutaric acid, phthalic acid, isophthalic acid, terephthalic acid, pyromellitic acid, trimellitic acid, dodecanedicarboxylic acid, and lactone polymers Can be exemplified.

The polyether polyols include:
Examples thereof include polyalkylene glycols such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and polyethylene propylene glycol. Examples of the polyester ether polyols include those obtained by adding an alkylene oxide such as ethylene oxide to the polyester polyol, Examples thereof include those having a hydroxyl group at a terminal obtained by condensing an ether polyol and the above-mentioned polycarboxylic acid.

Examples of the polycarbonate polyols include those having a hydroxyl group at the terminal of a linear aliphatic carbonate skeleton such as poly-1,6-hexane carbonate diol. Preferred among these polyol compounds are polytetramethylene glycol and polytetramethylene glycol.
-1,6-hexane carbonate diol and the like.

As the chain extender, a compound having at least two functional groups containing an active hydrogen atom reactive with an isocyanate group can be used. Typical examples thereof include water, Polyhydric alcohols, primary
Grade or secondary polyamines, hydrazine and derivatives thereof can be used.

Examples of the polyhydric alcohols include, for example,
Ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2- or 1,3-propylene glycol, 1,2-, 1,3- or 1,
4-butylene glycol, 2,2-dimethyl-1,3-propylene glycol, 1,6-hexanediol, 2,2,4-trimethyl
Aliphatic diols such as -1,3-pentanediol;
2,2,4,4-tetramethylcyclobutanediol, 1,3-cyclopentanediol, alicyclic diols such as methylenebis (4-hexanol); for example, 1,4-phenylenebis (2-hydroxyethylether), Aromatic diols such as 1,2-propylene glycol bis (2-hydroxyphenyl ether); and the like.

Examples of polyvalent amines include ethylenediamine, hexamethylenediamine, isophoronediamine, diaminodiphenylmethane, diethylenetriamine and the like. Examples of hydrazine derivatives include dimethylhydrazine and 1,6-hexamethylenebishydrazine. Substituted hydrazines; for example, dicarboxylic acids,
Reaction products of disulfonic acid, lactone or polyhydric alcohol with hydrazine; and the like.

Examples of the chain extender include, in addition to the above, those used for imparting ionicity to urethane prepolymers and urethane-based resins when they are emulsified, and specific examples thereof include: For example,
Dihydroxycarboxylic acids such as 2,2-dimethylolacetic acid, 2,2-dimethylolpropionic acid, 2,2-dimethylolbutyric acid, and 2,2-dimethylolvaleric acid; for example, 2,5-diaminobenzoic acid, α, ε- Diaminocarboxylic acids such as caproic acid (lysine) and 2-amino-5-guanidinovaleric acid (arginine); and alkyldialkanolamines such as methyldiethanolamine.

In the production of the urethane prepolymer having an isocyanate group at the terminal, the polyisocyanate compound and the polyol compound are generally prepared by mixing the polyisocyanate compound and the polyol compound in a nitrogen atmosphere so that the isocyanate group is larger than the hydroxyl group.
The reaction is preferably carried out at a temperature of about 25 to 110 ° C. with stirring in an organic solvent, optionally in the presence of a reaction catalyst.

Examples of the organic solvent usable here include ketones such as acetone and methyl ethyl ketone; ethers such as dioxane and tetrahydrofuran;
For example, esters such as ethyl acetate; aliphatic hydrocarbons such as heptane and octane; alicyclic hydrocarbons such as cyclohexane and methylcyclohexane;
And the like.

Useful reaction catalysts include, for example, tertiary amines such as triethylamine; inorganic salts such as stannous chloride; organometallic compounds such as di-n-butyltin dilaurate; Can be

The urethane prepolymer thus prepared is reacted with a chain extender according to a method known per se to obtain a urethane resin.

The urethane resin emulsion can be produced by reacting the urethane prepolymer with a chain extender according to the method described below.

The method for producing the cationic emulsion includes the steps of (1) polymerizing a urethane prepolymer having an isocyanate group at a terminal with a diol having a tertiary amino group as a chain extender, and then quaternizing agent or acid. A cationization by reacting a diol having a quaternary amino group as a chain extender, or (2) a urethane prepolymer having an isocyanate group at a terminal, and a polyalkylene polyamine as a chain extender. And then cationizing by reacting epihalohydrin with an acid, and the like. Examples of the method for producing an anionic emulsion include:
For example, (3) a method in which a urethane prepolymer having an isocyanate group at a terminal is polymerized using a dihydroxycarboxylic acid or a diaminocarboxylic acid as a chain extender, and then neutralized with an alkaline compound to form an anion, (4) A method in which a urethane prepolymer having an isocyanate group at a terminal obtained from a hydrophobic polyol and an aromatic polyisocyanate is sulfonated, neutralized with a tertiary amine and anionized, and the like. (5) a method of dispersing a urethane prepolymer having an isocyanate group at a terminal in an aqueous solution containing a diamine or the like as necessary using an emulsifier, and extending the chain with water or a diamine; A long-chain alcohol alkylene oxide is added to a urethane prepolymer having an isocyanate group at the terminal. A method of reacting a side condensate (a type of nonionic surfactant) with an amine having a hydrophilic group such as a hydroxyl group, (7) a urethane prepolymer having an isocyanate group at a terminal and reacting the chain extender with a urethane resin And mechanically dispersing in water using an emulsifier.

As the urethane resin emulsion usable in the present invention, in addition to these, a hydroxyl group-containing vinyl monomer such as 2-hydroxyethyl acrylate is introduced into a urethane prepolymer. Emulsion copolymerization of a polymer and the (meth) acrylic monomer; a part of the isocyanate group of the urethane prepolymer having an isocyanate group at the terminal is blocked with various blocking agents, or the urethane prepolymer or The urethane resin is reacted with a urethane prepolymer in which a part of isocyanate groups are blocked to obtain a urethane prepolymer or a urethane resin containing a blocked isocyanate in the molecule, which is emulsified in the same manner as described above. And the like.

Examples of the urethane resin emulsion which can be used in the present invention described above include “Adekabon titer HUX-240” and “Adekabon titer HUX-2”.
32, Adekabon titer HUX-320, Adekabon titer HUX-260 (all manufactured by Asahi Denka Kogyo Co., Ltd.), Superflex 100, Superflex 10
7, Superflex 110, Superflex 126, Superflex 150, Superflex 160, Superflex 190, Superflex 200, Superflex 41
0 "," Superflex 460 "(above, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.)," Ucoat UWS-145 "," Ucoat U
X-4300, U-coat UX-4230, Permarine UA-
150, Permarine UA-200, Permarine UA-30
0 '', `` Permarin UA-310 '' (Sanyo Chemical Industries, Ltd.)
Made), "Takeracks XW-77-X25", "Takeracks XW-75"
-X09 '', `` Takerac XW-74-X13 '' (all manufactured by Takeda Pharmaceutical Co., Ltd.), `` Resamine D-6190 '', `` Resamine D-620
0 "(above, manufactured by Dainichi Seika Kogyo Co., Ltd.).

Among these, the urethane resin emulsion used in the present invention has good mixing stability with the above-mentioned acrylic copolymer, and a mixture of these resin components and an inorganic filler used as required. It is preferable to use a nonionic or anionic urethane-based resin emulsion from the viewpoints of ease of preparation and storage stability of the obtained aqueous coating composition.

The content of the urethane resin fine particles in the treatment liquid of the present invention is generally 50% by weight or less, preferably 10 to 40% by weight.
It must be in the range of weight percent. If the amount exceeds the upper limit, the composition is not preferred because disadvantages such as a decrease in alkali resistance and a decrease in blocking resistance of the composition may occur.

The method for incorporating the urethane resin into the treatment liquid of the present invention is not particularly limited. For example, the aqueous dispersion of the acrylic copolymer and the urethane resin emulsion are mixed and stirred. The emulsion blending method in which the urethane resin is previously dissolved in any one of the monomers (a) to (e) or a mixture thereof during the production of the acrylic copolymer aqueous dispersion, followed by emulsion copolymerization. A method of performing the reaction, a seed polymerization method of performing an emulsion copolymerization reaction by adding the monomers (a) to (e) in the presence of a urethane-based resin emulsion, and the like, and the most easily and preferably An emulsion blending method that can obtain a blend is particularly preferably used.

The olefin-based copolymer fine particles used in the present invention include olefin-vinyl acetate copolymer, olefin-acrylic acid copolymer, olefin-acrylate ester copolymer, ionomer, olefin-vinylsilane copolymer, Examples thereof include maleic anhydride-modified polyolefin.

The content of the olefin-based copolymer fine particles in the treatment liquid of the present invention is usually 40% by weight or less, preferably
It needs to be in the range of 10 to 30% by weight. If the amount exceeds the upper limit, the composition is not preferred because disadvantages such as a decrease in alkali resistance and a decrease in blocking resistance of the composition may occur.

The method for incorporating the olefin-based copolymer fine particles into the treatment liquid of the present invention is not particularly limited. For example, the aqueous dispersion of the acrylic-based copolymer and the urethane-based resin emulsion may be mixed with each other. Examples include an emulsion blending method of mixing and stirring and mixing, and a method of dissolving the olefin-based copolymer fine particles and then performing an emulsion copolymerization reaction in the production of the acrylic copolymer-based aqueous dispersion. The emulsion blending method which can obtain a preferable composition is particularly preferably used.

Further, when the steel sheet obtained by using the treatment liquid of the present invention is used for applications subject to severe processing,
For the purpose of preventing film flaws during processing, a lubricant (fine particles) of a wax component may be blended and used. In this case, the addition amount is preferably 1 to 10% by weight. If the amount is less than the lower limit, the effect of improving the workability is small, and if it exceeds the upper limit, the corrosion resistance deteriorates.

The treatment liquid of the present invention may further contain an epoxy-based curing agent, an isocyanate-based curing agent, if necessary, for the purpose of further improving corrosion resistance and adhesion between the undercoat and the overcoat.
A curing agent such as an oxazoline-based curing agent can be used in combination. Further, within a range that does not impair the excellent effects of the present invention, a water-soluble inorganic substance such as silicate or alumina sol may be blended and used, or a surface tension reducing agent such as a fluorine-based surfactant may be blended and used. . In addition, coloring pigments such as titanium oxide and calcium carbonate, extenders, rust preventive pigments such as calcium phosphate, and the like can be added and used. Furthermore, thickeners, dispersants, film forming aids, defoamers, organic solvents,
Preservatives and the like can also be added.

When applying the treatment liquid to a zinc-based plated steel sheet, it is necessary that the dry film weight is 0.3 to ² g / m ² . If it is less than the lower limit, corrosion resistance is insufficient, and if it exceeds the upper limit, performance effects such as corrosion resistance are saturated, which is not preferable in terms of cost.

The coating method is not particularly limited, such as a roll coater, spray, dipping, etc., but from the viewpoint that a uniform film appearance is easily obtained, coating with a roll coater is preferred. At the time of application, it is preferable that the aqueous solution is adjusted to a solid content concentration of 5 to 25% by weight and dried at a heating rate of 10 ° C./sec or more so that the reached plate temperature is 80 to 200 ° C. If the solid content concentration of the aqueous solution is less than the lower limit, it is difficult to obtain a uniform coating appearance, and if it exceeds the upper limit, it becomes difficult to control the film thickness, which is not preferable. If the rate of temperature rise is less than 10 ° C./sec, the cause is not necessarily clear, but the uniformity of the film deteriorates and the corrosion resistance tends to deteriorate. Also, if the drying temperature is less than the lower limit,
Excessive moisture remains and corrosion resistance deteriorates, while 200 ° C
If it is excessive, thermal degradation of the resin film starts to occur, which is not preferable.

[0073]

EXAMPLES Next, the present invention will be described more specifically with reference to Examples, Comparative Examples, Reference Examples and Comparative Reference Examples.
The present invention is not limited to these. The evaluation of the coating film performance in Examples and Comparative Examples was performed according to the following test plate manufacturing method and each coating film performance test method.

Preparation of test plate: After an oil-coated electrogalvanized steel plate (zinc adhesion amount 20 g / m ² ) was alkali-degreased, a roll coater was used to dry the treatment liquid to 1.0 g / m ^2. Then, it was dried at 380 ° C. for 10 seconds (the maximum temperature of the sheet temperature was 150 ° C.) with a hot air drier to prepare a test plate. As a comparison material for each evaluation, a material obtained by subjecting the same original plate to a chromate treatment (Cr 30 mg / m ² ) containing 50% reduced chromic acid and colloidal silica was used.

Evaluation items and evaluation method of coating film performance: (1) Film forming property The state of the coating film surface of the test plate was observed and evaluated with a microscope. Criteria 基準: Completely uniform film formation ：: Cracks are slightly observed △: Many cracks are observed ×: Innumerable cracks are observed (whitening)

(2) Paint adhesion (primary) After the test plate was cured at room temperature for 24 hours, melamine / alkyd baking paint [“Amirac # 1000”, Kansai Paint Co., Ltd.]
Was coated so as to have a dry film thickness of 20 μm, and baked at 130 ° C. for 20 minutes using a hot air drier. Then, after standing at room temperature for 1 hour, cut in a grid with a width of 1 mm, and further extruded a grid cut portion from the back surface with a width of 5 mm or 8 mm using an “Elexen film strength tester” (manufactured by Yasuda Seiki Seisakusho Co., Ltd.).
The extruded portion was subjected to a peeling test using a cellophane tape, and the remaining area of the overcoat film was evaluated on a scale of 1 to 10.

(3) Paint adhesion (secondary) After the test plate was cured at room temperature for 24 hours, the same melamine / alkyd baking paint as used in the above (2) was dried to a film thickness of 20 μm.
m, and baked at 130 ° C. for 20 minutes with a hot air drier. After standing at room temperature for 1 hour, boiling for 1 hour, and then standing at room temperature for 1 hour, evaluation was performed in the same manner as in the above (2).

(4) Alkali Resistance After the test plate was cured at room temperature for 24 hours, 0.5 ml of a 5% by weight aqueous sodium hydroxide solution was added dropwise and left for 10 minutes. Thereafter, the dropped sodium hydroxide aqueous solution was removed, and the state of the coating film surface was observed and evaluated. Judgment criteria ◎: No abnormality ○: Slight swelling of the coating film △: Swelling of the coating film considerably (blackening of the steel plate surface slightly) ×: Dissolution of the coating film (blackening of the steel plate surface)

(5) Corrosion resistance (5-1) Flat part After the test plate was cured at room temperature for 24 hours, the back and side surfaces were masked with a polyester tape, and a salt spray test (35 ° C, 5 ° C) was performed according to JIS-Z-2371. % Aqueous sodium chloride solution), and the area (%) of rust (white rust + black rust) on the test plate after 24 hours, 72 hours, or 240 hours was calculated by an image analysis method. (5-2) Processed part After the test plate was cured at room temperature for 24 hours, it was extruded from the back surface by 7 mm using `` Electric film strength tester '', then the back and side surfaces were masked with polyester tape, and
A salt water spray test was performed in the same manner as in section -1), and the evaluation was performed in the same manner.

(6) Blocking resistance Two test plates were prepared in accordance with the above, and immediately after drying, the two test plates were overlaid with each other with the aqueous coating composition applied to each other, and pressed under a pressure of 50 kg / cm ² under a pressure of 50 kg / cm ^2. Left at 24 ° C. for 24 hours. Then, the superposed test plates were left at room temperature for 1 hour and then peeled off, and the surface condition and peeling feeling of the coating film were evaluated. Criteria ◎: No peeling, no trace ○: Slight peeling, no trace △: Significant peeling, partial trace ×: Adhesion is difficult to peel

(7) Scratch resistance A slider 10 mmφ steel ball, load 20
The weight was 0 g, and the appearance after sliding 10 times was visually judged. Judgment criteria ◎: No trace of scratches ○: Slight trace △: Not metallic luster, but trace ×: Complete metallic luster

Reference Example 1 In a reaction vessel equipped with a thermometer, a stirrer, a reflux condenser and a dropping funnel, an anionic reactive emulsifier “Adecaria Soap SE-10N” [glycerol-1
-Allyl-3-nonylphenyl-2-polyoxyethylene (n
= About 10) Sulfate ammonium salt system; about 10 active ingredients
0% by weight; manufactured by Asahi Denka Kogyo Co., Ltd.] ("SE-10N") and 151.3 parts by weight of water, and the temperature was raised to 70 ° C while replacing the inside of the reaction vessel with nitrogen. On the other hand, 28 parts by weight of water
-10N "was dissolved in 4 parts by weight, and 63.9 parts by weight of the monomer (a) methyl methacrylate (MMA), 28.1 parts by weight of 2-ethylhexyl acrylate (EHA), and acrylic acid as the monomer (b) (AA) 2 parts by weight, monomer (c) glycidyl methacrylate (GMA) 5 parts by weight, and monomer (d)
3-methacryloxypropyltrimethoxysilane [“KBM-503”; manufactured by Shin-Etsu Chemical Co., Ltd.] (“KBM”) 1
A pre-emulsion was prepared by adding, stirring, and emulsifying a mixed monomer consisting of parts by weight.

Next, while maintaining the internal temperature of the reaction vessel at 70 ° C., the pre-emulsion, 6.8 parts by weight of a 6% by weight aqueous solution of ammonium persulfate and 6.8 parts by weight of a 5.1% by weight aqueous solution of sodium metabisulfite were uniformly added over 4 hours. .
After completion of the sequential addition, the mixture was aged at 70 ° C. for 1.5 hours, cooled to room temperature, and neutralized with aqueous ammonia to obtain an aqueous dispersion of an acrylic copolymer.

Table 1 shows the composition of the monomers used in the emulsion polymerization, the type of the reactive emulsifier, the amount used, and the initial / sequential addition ratio.
Shown in

Reference Example 2 and Comparative Reference Examples 1-2 In Example 1, instead of using 2 parts by weight of AA as the monomer (b), ω-carboxy-polycaprolactone mono (meth) acrylate (n = About 2) using 5 parts by weight of (CCMA) or 15 parts by weight of methacrylic acid (MAA), or without using the monomer (b),
Further, an aqueous dispersion of an acrylic copolymer was obtained in the same manner as in Reference Example 1, except that the amounts of EHA and MMA used were slightly adjusted accordingly.

Table 1 shows the composition of the monomers used in the emulsion polymerization, the type of the reactive emulsifier, the amount used, and the initial / sequential addition ratio.
Shown in

(Reference Example 3 and Comparative Reference Examples 3 and 4) In Reference Example 1, instead of using 5 parts by weight of GMA as the monomer (c), 10 parts or 25 parts by weight of GMA was used. Monomer
An aqueous acrylic copolymer dispersion was obtained in the same manner as in Reference Example 1 except that (c) was not used and the amounts of EHA and MMA used were slightly adjusted accordingly.

Table 1 shows the composition of the monomers used in the emulsion polymerization, the type of the reactive emulsifier, the amount used, and the initial / sequential addition ratio.
Shown in

(Reference Examples 4 to 6)
The type and amount of the monomer (b) were changed as shown in the figure.If necessary, the amount of the monomer (d) `` KBM '' was changed, and EHA was used as the monomer (a). Change the usage ratio with MMA, or E
Use butyl acrylate (BA) instead of HA, use styrene (St) as the monomer (e) if necessary, and use the anionic reactive emulsifier "SE-10N" as necessary instead of using , An anionic reactive emulsifier “AQUALON H
S-10 "[polyoxyethylene (n = about 10) nonylpropenyl phenyl ether sulfate sodium salt;
Active ingredient: about 100% by weight; manufactured by Asahi Denka Kogyo Co., Ltd.) (“HS-1
0)), the amount used and the ratio of the initial addition and the sequential addition are changed as shown in Table 1, and if necessary, the nonionic reactive emulsifier “ADEKAREASORP NE- 10 "[glycerol-1-allyl-3-nonylphenyl-2-polyoxyethylene (n = about 10) ether type; active ingredient about 100% by weight; manufactured by Asahi Denka Kogyo Co., Ltd.] (" NE
-10 "), and an aqueous dispersion of an acrylic copolymer was obtained in the same manner as in Reference Example 1 except that the amount of water used was changed accordingly.

Table 1 shows the composition of the monomers used in the emulsion polymerization, the type of the reactive emulsifier, the amount used, and the initial / sequential addition ratio.
Shown in

Reference Examples 7 and 8 An aqueous acrylic copolymer dispersion was obtained in the same manner as in Reference Example 1 except that the amount of the anionic reactive emulsifier "SE-10N" was changed. .

Table 1 shows the composition of the monomers used in the emulsion polymerization, the type of the reactive emulsifier, the amount used, and the initial / sequential addition ratio.
Shown in

(Comparative Reference Examples 5 to 6)
As shown in Table 1, the monomer composition was changed, and instead of using the anionic reactive emulsifier "SE-10N", a conventional anionic emulsifier "Neogen R" [dodecylbenzenesulfonic acid sodium salt; % By weight; Daiichi Kogyo Pharmaceutical Co., Ltd.
Or an anionic emulsifier "Hitenol N"
-08 "[polyoxyethylene nonylphenyl ether sulfate ammonium salt; about 100% by weight of active ingredient;
Daiichi Kogyo Seiyaku Co., Ltd.] (“N-08”), changing the amount of water used and the ratio of initial addition and sequential addition, and changing the amount of water used accordingly. An acrylic copolymer aqueous dispersion was obtained in the same manner as in Reference Example 1 except that the monomer composition was changed.

Table 1 shows the composition of the monomers used in the emulsion polymerization, the type of the reactive emulsifier, the amount used, and the initial / sequential addition ratio.
Shown in

[0095]

[Table 1]

Examples 1 to 9, Comparative Examples 1 to 6 The acrylic copolymer aqueous dispersions obtained in Reference Example 1 were
Polyester ether urethane emulsion "Adeka Bon Titer HUX-320" [manufactured by Asahi Denka Kogyo Co., Ltd .; solid content: approx. 3
3% by weight, particle diameter of about 40 nm] (“HUX-320”) and / or polyether-based urethane emulsion “Adekabon Titer A-6-4” (manufactured by Asahi Denka Kogyo Co., Ltd .; solid content: about 33% by weight; Particle size of about 40nm] (“A-6-4”) and / or polycarbonate urethane emulsion “Permarin UA-
300 "(manufactured by Sanyo Chemical Industries, Ltd .; solid content: about 39% by weight, particle size: about 80 nm) (" UA-300 ") and / or ethylene acrylic acid copolymer emulsion" S-3121 "or" S-702 "
4 "(all manufactured by Toho Chemical Co.) and / or colloidal silica (Snowtex series manufactured by Nissan Chemical Co., Ltd., anionic colloidal silica) were uniformly stirred and mixed at a mixing ratio shown in Table 2 to prepare a treatment liquid. A test plate was prepared according to the method described above, and the performance was evaluated. Table 3 shows the results of the performance evaluation of the steel sheet.

Examples 10 to 16 and Comparative Examples 7 to 12 Acrylic copolymer and urethane emulsion, ethylene acrylic acid copolymer emulsion, colloidal silica of Reference Examples 2 to 8 and Comparative Reference Examples 1 to 6 in Table 1 Was uniformly stirred and mixed at a mixing ratio shown in Table 2 to prepare a treatment liquid, and a test plate was prepared according to the method described above, and the performance was evaluated.
Table 3 shows the results of the performance evaluation of the steel sheet.

[0098]

[Table 2]

[0099]

[Table 3]

As described above, those within the scope of the present invention include:
Although excellent properties equivalent to or higher than that of the comparative chromate material are shown, those having properties out of the range of the present invention have some poor performance.

Examples 17 to 23 Based on the processing liquid used in the previous Example 3, the processing liquid was prepared by changing the type of silica, and a test plate was prepared according to the above-described method, and the performance was evaluated. Was. Table 4 shows the results of the performance evaluation of the steel sheet.

Examples 20 to 23 and Comparative Example 13 Based on the paint used in Example 3 above, a low molecular weight polyolefin wax emulsion "Chemipearl W-700" (manufactured by Mitsui Chemicals) or a montan wax derivative as a wax component Emulsion "Maycatex P-
4 "(manufactured by Meisei Chemical Industry Co., Ltd.) was added to prepare a treatment liquid, and a test plate was prepared according to the method described above, and the performance was evaluated. Table 4 shows the results of the performance evaluation of the steel sheet.

[0103]

[Table 4]

As described above, even when the type of silica is changed, the performance is almost comparable to that of a chromate. However, the smaller the particle diameter of an anionic or nonionic material, the better the corrosion resistance. Also, the addition of the wax component significantly improved the scratch resistance (it was better than the comparative chromate without the wax). However,
When the amount of wax added exceeded the range of the present invention, the corrosion resistance tended to deteriorate. Although not shown in Table 4, the film-forming properties, paint adhesion, alkali resistance, and blocking resistance were all good.

Examples 24 to 30 and Comparative Examples 14 to 16 Using the same paint as in Example 21 above, a test plate was prepared by changing the dry film adhesion amount, the drying temperature and the drying speed, and the performance was evaluated. Was. Table 5 shows the results of the performance evaluation of the steel sheet.

[0106]

[Table 5]

As described above, those within the scope of the present invention include:
It shows excellent properties equal to or higher than that of the comparative chromate material (although not shown in Table 5, the film-forming properties, paint adhesion, alkali resistance, and blocking resistance were all good). For those that fall outside the scope of the invention,
Corrosion resistance deteriorated.

[0108]

According to the present invention, there is provided a conventional chromate-treated steel sheet containing no harmful hexavalent chromium on a steel sheet, no emission of hexavalent chromium in a manufacturing process, and containing hexavalent chromium. A method for producing a galvanized steel sheet having equivalent corrosion resistance and paint adhesion is provided.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme court ゛ (Reference) C23C 22/05 C23C 22/05 22/50 22/50 22/53 22/53 (72) Inventor Kimitaka Hayashi 1 at Fujimachi, Hirohata-ku, Himeji-shi Nippon Steel Corporation Hirohata Works (72) Inventor Ikuo Kikuchi 1 at Fujimachi, Hirohata-ku, Himeji-shi Nippon Steel Corporation Hirohata Works (72) Inventor Nobuo Nakagawa 53 Yoneyama-Minamicho, Sano-shi, Tochigi Japan Carbide Industrial Co., Ltd.Sano Ryo (72) Inventor Yoshihiro Maeyama 53 Yoneyama-Minamicho, Sano-shi, Tochigi Pref. 1-37-41 Ichihanazaki F-term (reference) 4D075 AE03 BB24Z BB93Z CA13 CA33 DA06 DB05 DC02 DC12 DC18 EA02 EA37 EB13 EB22 EB38 EB56 EC03 EC54 4J038 BA212 CB002 CG011 CG061 CG141 CH031 CH041 C H171 CL001 DB361 DG002 GA06 HA446 MA02 NA03 NA12 PA07 PC02 4K026 AA02 AA07 AA22 BA01 BB04 BB06 BB10 CA16 CA39 CA41 DA11 DA16

Claims (4)

[Claims] 1. The following (A) to (D), wherein the total of (A) to (D) is 100% by weight. (A) The following monomers (a) to (e) are intramolecularly Acrylic copolymer fine particles (active ingredient) obtained by emulsion polymerization in the presence of a reactive emulsifier having a radical polymerizable unsaturated group (active ingredient) 10 to 99% by weight, (a) represented by the following general formula (1) (Meth) acrylate monomer 30 to 98.4% by weight, [Wherein, R ¹ is hydrogen or a methyl group, and R ² is C 1-12
(B) 0.5 to 10% by weight of an α, β-ethylenically unsaturated monomer having a carboxyl group in the molecule, and (c) α, β having a glycidyl group in the molecule. -1 to 20% by weight of ethylenically unsaturated monomer,
(d) 0.1 to 10% by weight of an α, β-ethylenically unsaturated monomer having an alkoxysilane group in the molecule, (e) copolymerizable with the above (a) to (d) (a) to (d) 0) to 30% by weight of the monomers other than), wherein the total of (a) to (e) is 100% by weight. (B) 0 to 50% by weight of urethane resin fine particles (active ingredient);
Zinc-based coated steel sheet is prepared with an aqueous solution containing (C) olefin copolymer fine particles (active ingredient) 0 to 40% by weight and (D) colloidal silica fine particles (active ingredient) 1 to 40% by weight as essential components. treatment, and dried without washing 0.3 to 2 g / m ²
Surface treatment method for galvanized steel sheet characterized by forming a film of. 2. The method according to claim 1, wherein the average particle diameter of the colloidal fine particles having anionic or nonionic properties is less than 150 nm. 3. The surface treatment method for a galvanized steel sheet according to claim 1, further comprising a treatment with an aqueous solution containing 1 to 10% by weight of fine particles of a wax component. 4. The method according to claim 1, wherein the solid content of the aqueous solution is 5 to 25% by weight, and the temperature is 10 ° C./sec.
A surface treatment method for a zinc-based plated steel sheet, characterized in that drying is performed so that the reached sheet temperature becomes 80 to 200 ° C. at the above-mentioned heating rate.