JP2003105554A - Surface treated steel sheet having excellent white rust resistance, and production method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface treated steel sheet which contains no chromium in a surface treatment film but still exhibits excellent corrosion resistance. SOLUTION: In the surface treated steel sheet, by realizing a reaction layer between a barrier layer and plating metal effective for corrosion inhibition not as a double layer but in a single layer film, corrosion resistance of a high degree can be obtained. The surface of a zinc base or aluminum base plated steel sheet is provided with a surface treatment film formed by applying a surface treatment composition containing (a) a water dispersible resin and/or or water soluble resin which is a reaction product between an epoxy group- containing resin and an active hydrogen-containing compound and in which part or the whole of the active hydrogen-containing compound is a hydrazine derivative containing active hydrogen, (b) a silane coupling agent, and (c) phoshoric acid and/or hexafluoro metal acid, and drying the same composition.

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 which is most suitable for use in automobiles, home appliances, and building materials, and particularly when the surface-treated steel sheet is manufactured and the surface-treated coating does not contain chromium at all. The present invention relates to a steel plate and a manufacturing method thereof.

[0002]

2. Description of the Related Art The purpose of improving corrosion resistance (white rust resistance, red rust resistance) on the surface of zinc-based plated steel sheets or aluminum-based plated steel sheets for steel sheets for home appliances, steel sheets for building materials, and steel sheets for automobiles. Steel sheets that have been subjected to chromate treatment with a treatment liquid containing chromic acid, dichromic acid or salts thereof as a main component are widely used. This chromate treatment is an economical treatment method which has excellent corrosion resistance and can be performed relatively easily.

Chromate treatment uses hexavalent chromium, which is a pollution control substance. This hexavalent chromium is treated in a closed system in the treatment process and is completely reduced / recovered and is not released to nature. Moreover, since the elution of chromium from the chromate film can be made almost zero by the sealing action of the organic film,
The hexavalent chromium does not substantially pollute the environment or the human body. However, due to recent global environmental problems,
There is a growing movement to voluntarily reduce the use of heavy metals including hexavalent chromium. In addition, in order to prevent environmental pollution when throwing away shredder dust from discarded products, there is a move to reduce or eliminate heavy metals in products as much as possible.

In view of the above, in order to prevent the occurrence of white rust on the zinc-based plated steel sheet, many treatment techniques that do not rely on chromate treatment, so-called chromium-free techniques, have been proposed. For example, using an inorganic compound, an organic compound, an organic polymer material, or a solution combining these, dipping,
There is a method of forming a thin film by a method such as coating or electrolytic treatment.

Specifically, the following methods can be mentioned. (1) A method of forming a film by immersing in a treatment liquid containing a polyhydric phenolcarboxylic acid such as tannic acid and a silane coupling agent or by applying the treatment liquid (for example,
Japanese Unexamined Patent Publication No. 7-216268 and Japanese Patent No. 2968959.
(2) A method of forming a film by using a treatment liquid in which a polyhydric phenolcarboxylic acid such as tannic acid or a phosphoric acid compound is mixed with an organic resin (for example, JP-A-8-325760, JP-A-2000- 34578, JP 2000-
(199076, JP-A-2000-248380) (3) A method of applying a treatment liquid containing an organic resin and a silane coupling agent (for example, JP-A-10-80664)

[0006]

As the method (1) above, there is a method of treating with a polyhydric phenolcarboxylic acid, a silane coupling agent, and an aqueous solution containing a metal ion. The method shown in 7-216268 is mentioned. However, this treatment method has a drawback that sufficient corrosion resistance cannot be obtained, although good adhesion can be obtained.

As a method of the above (2), for example, Japanese Patent Laid-Open No. 8-
Japanese Patent No. 325760 discloses a method of performing treatment with a treatment liquid containing a polyhydric phenolcarboxylic acid, an organic resin and metal ions. Also, Japanese Patent Laid-Open No. 2000-34578
The publication discloses a method of immersing in a treatment liquid added with an organic resin and a phosphoric acid compound or applying the treatment liquid and then drying. However, although the protective film formed by these treatment liquids contributes to the improvement of the corrosion resistance to some extent, it cannot obtain the high degree of corrosion resistance as in the case of the chromate treatment.

Further, as the method of (3) above, Japanese Patent Laid-Open No.
Japanese Unexamined Patent Publication No. 0-80664 discloses a method of forming a film by applying a treatment liquid containing an organic resin and a silane coupling agent. The silane coupling is applied to a metal surface which is inactive in the treatment liquid. The agent cannot exert a sufficient effect, and thus the adhesiveness and corrosion resistance obtained are not sufficient. Therefore, an object of the present invention is to provide a surface-treated steel sheet which solves the above-mentioned problems of the prior art and does not contain heavy metals such as chromium in the surface-treated coating, and which has excellent corrosion resistance.

[0009]

The present inventors have solved the above-mentioned problems.
In order to solve the problem, the corrosion
The following studies were conducted on the principle of food suppression. surface
Corrosion of galvanized steel sheet with a treated coating is
Proceed in steps. (1) Corrosion factors (oxygen, water, chlorine ion) in the surface treatment film
Etc.) infiltrate, and these enter the plating film / surface treatment film boundary
Diffuse to the surface. (2) At the plating film / surface treatment film interface,
Zinc is dissolved by such a redox reaction. Cathode reaction: 2H_TwoO + O_Two+ 4e⁻ → 4OH⁻ Anode reaction: 2Zn → 2Zn²⁺+ 4e⁻

Therefore, in order to improve the corrosion resistance of the zinc-based plated steel sheet, it is essential to suppress the progress of both reactions (1) and (2) above. A barrier layer (mainly acts to suppress the above cathode reaction) and a coating layer having a reaction layer (mainly acts to suppress the above anode reaction) with the plating metal that inactivates the plating coating surface layer, and Preferably, it is most effective to have a film structure in which a self-repairing action works when a defect occurs in the reaction layer.

The inventor of the present invention does not use such a film structure as a two-layer film formed by separately coating a barrier layer-forming component and a reaction layer-forming component as in the prior art, but by performing a single coating. Realization within the formed single-layer coating, specifically, the above barrier layer (organic resin matrix layer described below) above the coating and the above reaction layer (amorphous compound layer described below) below the coating. It has been found that by constituting each of them, and more preferably by depositing a substance that causes a self-repairing action in the film, a remarkable corrosion resistance improving effect can be obtained by the synergistic effect of these. When such a single-layer film is defined as a pseudo-two-layer film, a space between the barrier layer and the reaction layer forming this pseudo-two-layer film is a two-layer film formed by conventional double coating. There is no clear interface. Rather, it is considered that the graded composition of both can exert a high degree of corrosion resistance improving effect which cannot be obtained by the conventional single layer coating.

As a result of intensive studies by the present inventors, the above-mentioned pseudo two-layer film is a reaction product of an epoxy group-containing resin and an active hydrogen-containing compound, and a part of the active hydrogen-containing compound or A surface treatment composition in which a silane coupling agent and a specific acid component (phosphoric acid and / or hexafluorometal acid) are mixed with a water-dispersible resin or a water-soluble resin, all of which are hydrazine derivatives having active hydrogen, is a zinc-based composition. It was found that it can be obtained by applying it to the surface of a plated steel sheet or an aluminum-based plated steel sheet and drying it.

It has been known that a silane coupling agent has a function of improving the adhesiveness between an inorganic compound and an organic compound, and the adhesiveness between a plating metal and a water-dispersible resin or a water-soluble resin is known. It is possible to increase. In contrast to the known effect of such a silane coupling agent, in the present invention, the acid component contained in the surface treatment composition activates the surface of the plating film by etching, and the silane coupling agent causes the activated plating to proceed. It is considered that, by chemically bonding with both the metal and the film-forming resin, extremely excellent adhesion between the plated metal and the film-forming resin can be obtained. That is, by adding a silane coupling agent and a specific acid component in the surface treatment composition in a composite manner, the adhesion between the plating metal and the film-forming resin is remarkably improved as compared with the case where the silane coupling agent is added alone. It is considered that this is increased and this contributes to the improvement of corrosion resistance.

In the present invention, the mechanism of forming the pseudo two-layer coating having the above-mentioned coating structure is not necessarily clear, but the reaction between the acid component in the surface treatment composition and the plating coating surface is involved in the coating formation. there is a possibility. On the other hand, the following actions involving the silane coupling agent are also considered. That is, since the silane coupling agent hydrolyzed in the aqueous solution has a silanol group (Si-OH), the hydrogen bonding adsorption action of the silane coupling agent on the plating metal surface activated by the acid component is promoted, and the plating The silane coupling agent is concentrated on the metal surface, and then dried to cause a dehydration condensation reaction to form a strong chemical bond, thereby forming a reaction layer at the bottom of the film and a water-dispersible resin concentrated at the top of the film. There is also a possibility that the barrier layer is formed by the water-soluble resin and / or the mechanism. In addition, there is a possibility that the above-mentioned effects are combined. In addition, in the process of forming the film as described above, it is considered that the reaction product (compound) of the dissolved plating metal such as zinc and the acid component is precipitated in the film.

The anticorrosion mechanism of such a pseudo two-layer coating is not necessarily clear, but as the individual anticorrosion mechanism, a dense organic polymer can be prepared by adding a hydrazine derivative to the epoxy group-containing resin as the barrier layer. A film is formed, which suppresses the penetration of corrosion factors (oxygen, water, chlorine ions, etc.) and effectively suppresses the cathodic reaction that causes corrosion, and also forms a plating metal ion eluted by the corrosion reaction. The free hydrazine derivative inside will trap and form a stable insoluble chelate compound layer, and the above reaction layer will effectively suppress the anode reaction that inactivates the plating coating surface layer and causes corrosion. Furthermore, the precipitation compound that has precipitated in the film dissolves in a corrosive environment to generate an acid component (phosphate ion, etc.), and this acid component The self-repairing action of capturing metal ions such as zinc ions eluted from the plating film (combining with metal ions to form an insoluble compound), and further, the silane coupling agent was activated by the acid component. It is thought that it is possible to form a dense film with high adhesion by firmly bonding to the plated metal surface, suppressing the dissolution of the plated metal, and also bonding to the film forming resin. Therefore, it is considered that extremely excellent corrosion resistance (white rust resistance) can be obtained.

Further, it has been found that further excellent corrosion resistance can be obtained by adding a water-soluble phosphate or a non-chromium type anticorrosive additive to this surface treatment composition. Similar to the above, the water-soluble phosphate also exhibits a barrier property against corrosion factors by the sparingly soluble film, and the phosphate component captures the eluted plating metal ion and forms an insoluble compound with the plating metal ion. It is possible to do it. Further, the non-chromium-based anticorrosive additive forms a protective film at the starting point of corrosion, so that further excellent anticorrosive performance can be obtained. In fact, these combined effects result in very good anticorrosion performance.

The present invention has been made on the basis of such findings, and its features are as follows. [1] On the surface of a zinc-plated steel sheet or an aluminum-plated steel sheet, (a) a reaction product of an epoxy group-containing resin and an active hydrogen-containing compound, and part or all of the active hydrogen-containing compound is active. A water-dispersible resin and / or a water-soluble resin which is a hydrazine derivative having hydrogen,
(B) silane coupling agent, (c) phosphoric acid and /
Alternatively, the film thickness formed by applying a surface treatment composition containing a hexafluorometal acid and drying it is 0.1.
A surface-treated steel sheet having excellent white rust resistance, characterized by having a surface-treated film of 02 to 5 μm.

[2] In the surface-treated steel sheet according to [1] above, the surface-treatment composition contains the silane coupling agent in an amount of 1 to 300 parts by weight based on 100 parts by weight of the solid content of the water-dispersible resin and / or the water-soluble resin. Parts, 0.1 to 80 parts by weight of phosphoric acid and / or hexafluorometallic acid with respect to 100 parts by weight of the solid content of the water-dispersible resin and / or the water-soluble resin. Excellent surface-treated steel sheet. [3] In the surface-treated steel sheet according to the above [1] or [2], the surface-treatment composition further comprises a water-soluble phosphate with respect to 100 parts by weight of the water-dispersible resin and / or the solid content of the water-soluble resin. A surface-treated steel sheet having excellent white rust resistance, which is characterized by containing 0.1 to 60 parts by weight in terms of solid content.

[4] In the surface-treated steel sheet of [3] above, the surface-treatment composition is a water-soluble phosphate having a molar ratio [cation] / [P ₂ O ₅ ] of a cation component and a P ₂ O ₅ component. 0.4 to 1.0 and the cationic species are Mn, M
A surface-treated steel sheet having excellent white rust resistance, which contains one or more water-soluble phosphates selected from g, Al and Ni. [5] In the surface-treated steel sheet according to any one of the above [1] to [4],
The surface treatment composition further contains a non-chromium rust preventive additive in an amount of 0.1 to 50 parts by weight based on the solid content of 100 parts by weight of the water-dispersible resin and / or the water-soluble resin. Surface-treated steel sheet with excellent white rust resistance.

[6] In the surface-treated steel sheet according to the above [5], the surface-treatment composition is used as a non-chromium rust preventive additive (e)
A surface-treated steel sheet having excellent white rust resistance, which contains one or more rust preventive additives selected from the group of 1) to (e5). (E1) silicon oxide (e2) calcium and / or calcium compound (e3) sparingly soluble phosphoric acid compound (e4) molybdic acid compound (e5) selected from triazoles, thiols, thiadiazoles, thiazoles and thiurams One or more organic compounds containing S atom [7] In the surface-treated steel sheet according to any one of the above [1] to [6],
White rust resistance, characterized in that the surface treatment composition further contains a solid lubricant in an amount of 1 to 50 parts by weight based on 100 parts by weight of the water-dispersible resin and / or the water-soluble resin. Excellent surface treated steel sheet.

[8] In the surface-treated steel sheet according to any one of the above [1] to [7], the surface-treatment composition comprises at least a silane coupling agent having an amino group as a reactive functional group as a silane coupling agent. A surface-treated steel sheet excellent in white rust resistance, characterized by containing one kind. [9] In the surface-treated steel sheet according to any of the above [1] to [8],
The surface treatment composition contains Ti as hexafluorometal acid,
A surface-treated steel sheet having excellent white rust resistance, which contains at least one hexafluorometal acid containing one or more elements selected from Si and Zr. [10] In the surface-treated steel sheet according to any one of [5] to [9] above, the surface-treatment composition contains calcium ion-exchanged silica as a non-chromium rust-preventive additive, and is resistant to white rust. Excellent surface treated steel sheet.

[11] In the surface-treated steel sheet according to any one of the above [1] to [10], the surface-treatment composition contains a water-dispersible resin as the component (a), and the water-dispersible resin is A polyalkylene glycol-modified epoxy resin (A) obtained by reacting a polyalkylene glycol having a number average molecular weight of 400 to 20,000, a bisphenol type epoxy resin, an active hydrogen-containing compound and a polyisocyanate compound, and the polyalkylene glycol modified epoxy resin ( A surface excellent in white rust resistance, which is an aqueous epoxy resin dispersion obtained by reacting an epoxy group-containing resin (B) other than A) with a hydrazine derivative (C) having active hydrogen. Treated steel plate.

[12] In the surface-treated steel sheet according to any one of the above [1] to [10], the surface-treatment composition contains a water-dispersible resin as the component (a), and the water-dispersible resin is A polyalkylene glycol-modified epoxy resin (A) obtained by reacting a polyalkylene glycol having a number average molecular weight of 400 to 20,000, a bisphenol type epoxy resin, an active hydrogen-containing compound and a polyisocyanate compound, and the polyalkylene glycol modified epoxy resin ( Aqueous epoxy resin obtained by reacting an epoxy group-containing resin (B) other than A), a hydrazine derivative (C) having active hydrogen, and an active hydrogen-containing compound (D) other than the hydrazine derivative (C) A surface-treated steel sheet with excellent white rust resistance, which is a dispersion liquid.

[13] In the surface-treated steel sheet according to [11] or [12], the epoxy group-containing resin (B) has a number average molecular weight of 1,500 to 10,000 and an epoxy equivalent of 150 to 5,000.
The surface-treated steel sheet excellent in white rust resistance, which is characterized by being a bisphenol A type epoxy resin. [14] In the surface-treated steel sheet according to any one of [11] to [13], the aqueous epoxy resin dispersion liquid further contains a curing agent having a group capable of cross-linking with a hydroxyl group. Excellent surface-treated steel sheet.

[15] On the surface of the zinc-based plated steel sheet or the aluminum-based plated steel sheet, P, Zn or / and A
A surface having a film thickness of 0.02 to 5 μm, which is composed of an amorphous compound layer containing 1 and O and an organic resin matrix layer having an epoxy group-containing resin modified with a hydrazine derivative as a matrix thereover. A surface-treated steel sheet with excellent white rust resistance, which has a treated film. [16] The surface-treated steel sheet according to the above [15], wherein the surface-treated coating further contains a silane compound, which is excellent in white rust resistance. [17] In the surface-treated steel sheet according to [15] or [16], the surface-treated film is P, Zn or / and Al, and O.
A surface-treated steel sheet having excellent white rust resistance, which comprises a precipitation compound containing

[18] The surface-treated steel sheet according to any one of the above [15] to [17], characterized in that the surface-treated coating contains a precipitation compound containing P, Zn or / and Al, Si and O. A surface-treated steel sheet with excellent white rust resistance. [19] The surface-treated steel sheet according to any one of [15] to [18] above, which is a surface-treated steel sheet having a surface-treated coating on the surface of a zinc-based plated steel sheet, wherein Zn and P in the amorphous compound layer are A surface-treated steel sheet excellent in white rust resistance, characterized in that the molar ratio [Zn] / [P] is 0.9 to 1.4. [20] The surface-treated steel sheet according to any one of [17] to [19] above, which is a surface-treated steel sheet having a surface-treated coating on the surface of a zinc-based plated steel sheet, wherein Zn in a precipitation compound contained in the surface-treated coating is contained. And P have a molar ratio [Zn] / [P] of 0.9 to 1.
4. A surface-treated steel sheet having excellent white rust resistance, characterized in that

[21] The surface-treated steel sheet according to any one of [17] to [19] above, which is a surface-treated steel sheet having a surface-treated coating on the surface of a zinc-based plated steel sheet, the precipitation compound being contained in the surface-treated coating. A surface-treated steel sheet having excellent white rust resistance, characterized in that the Zn: P molar ratio [Zn] / [P] is less than 1.0. [22] In the surface-treated steel sheet according to any one of the above [15] to [21], the surface treatment film further contains a non-chromium rust preventive additive,
0.1% by solid content based on 100 parts by weight of organic resin solid content
A surface-treated steel sheet having excellent white rust resistance, which is characterized by containing 50 to 50 parts by weight.

[23] In the surface-treated steel sheet according to [22] above,
The surface treatment film has the following (e)
A surface-treated steel sheet having excellent white rust resistance, which contains one or more rust preventive additives selected from the group of 1) to (e5). (E1) silicon oxide (e2) calcium and / or calcium compound (e3) sparingly soluble phosphoric acid compound (e4) molybdic acid compound (e5) selected from triazoles, thiols, thiadiazoles, thiazoles and thiurams One or more S-containing organic compounds

[24] In the surface-treated steel sheet according to [23] above,
A surface-treated steel sheet excellent in white rust resistance, characterized in that the surface-treated coating contains calcium ion-exchanged silica as a non-chromium-based rust preventive additive. [25] In the surface-treated steel sheet according to any one of the above [15] to [24], the surface-treated film further contains a solid lubricant in an amount of 1 to 50 parts by weight based on 100 parts by weight of the solid content of the organic resin. A surface-treated steel sheet excellent in white rust resistance characterized by containing. [26] An organic resin having a film thickness of 0.02 μm or more and less than 5 μm on the upper layer of the surface-treated film in which the film thickness of the surface-treated steel sheet according to any one of the above [1] to [25] is 0.02 μm or more and less than 5 μm A surface-treated steel sheet having excellent white rust resistance, which has a film and has a total film thickness of 5 μm or less of the organic resin film and the surface-treated film.

[27] The method for producing a surface-treated steel sheet according to any one of [1] to [25] above, wherein (a) an epoxy group-containing resin and an active material are activated on the surface of a zinc-based plated steel sheet or an aluminum-based plated steel sheet. (B) Silane coupling with a water-dispersible resin and / or a water-soluble resin, which is a reaction product with a hydrogen-containing compound, and in which a part or all of the active hydrogen-containing compound is a hydrazine derivative having active hydrogen. Agent,
(C) A surface treatment composition containing phosphoric acid and / or hexafluorometalic acid and having a pH adjusted to 0.5 to 6 is applied and heated at an ultimate plate temperature of 50 ° C to 300 ° C without washing with water. A method for producing a surface-treated steel sheet having excellent white rust resistance, which comprises drying to form a surface-treated film having a film thickness of 0.02 to 5 μm. [28] An organic resin coating having a coating thickness of 0.02 μm or more and less than 5 μm is formed on the upper layer of the surface-treated coating having a coating thickness of 0.02 μm or more and less than 5 μm of the surface-treated steel sheet obtained by the production method of [27] above. A method for producing a surface-treated steel sheet having excellent white rust resistance, which is characterized in that the total thickness of the surface-treated coating and the coating is 5 μm or less.

[0031]

BEST MODE FOR CARRYING OUT THE INVENTION The details of the present invention and the reasons for limitation thereof will be described below. Examples of the zinc-based plated steel sheet as the base of the surface-treated steel sheet of the present invention include a galvanized steel sheet and Zn-Ni.
Alloy-plated steel sheet, Zn-Fe alloy-plated steel sheet (electroplated steel sheet and galvannealed steel sheet), Zn-Cr
Alloy-plated steel sheet, Zn-Mn alloy-plated steel sheet, Zn-C
o alloy plated steel sheet, Zn-Co-Cr alloy plated steel sheet,
Zn-Cr-Ni alloy plated steel sheet, Zn-Cr-Fe alloy plated steel sheet, Zn-Al alloy plated steel sheet (for example, Z
n-5% Al alloy plated steel plate, Zn-55% Al alloy plated steel plate, etc.), Zn-Mg alloy plated steel plate, Zn-A
1-Mg plated steel sheet (for example, Zn-6% Al-3% M
g alloy plated steel sheet, Zn-11% Al-3% Mg alloy plated steel sheet, and a zinc-based composite plated steel sheet (for example, Zn-SiO) in which metal oxides, polymers and the like are dispersed in the plating film of these plated steel sheets. ₂ dispersion-plated steel sheet) or the like can be used.

Further, it is also possible to use a multi-layer plated steel sheet obtained by plating two or more layers of the same kind or different kinds among the above-mentioned plating. Further, as the aluminum-based plated steel sheet serving as the base of the surface-treated steel sheet of the present invention, an aluminum plated steel sheet, an Al-Si alloy plated steel sheet, or the like can be used. Further, as the plated steel sheet, a steel sheet surface may be preliminarily plated with Ni or another thin coating, and then various kinds of plating as described above may be performed thereon. As the plating method, any of an electrolysis method (electrolysis in an aqueous solution or electrolysis in a non-aqueous solvent), a melting method and a vapor phase method can be adopted. Furthermore, in order to prevent blackening of the plating, 1 to 2000 in the plating film
Even if a trace element of Ni, Co, Fe of about ppm is deposited, or the surface of the plating film is subjected to a surface conditioning treatment with an alkaline aqueous solution or an acidic aqueous solution containing Ni, Co, Fe, these elements are deposited. Good.

Next, the surface treatment film formed on the surface of the zinc-based plated steel sheet or the aluminum-based plated steel sheet and the surface treatment composition for forming this film will be described.
The surface-treated coating formed on the surface of the zinc-plated steel sheet or the aluminum-plated steel sheet in the surface-treated steel sheet of the present invention is (a) a reaction product of an epoxy group-containing resin and an active hydrogen-containing compound, and A water-dispersible resin and / or a water-soluble resin in which a part or all of the active hydrogen-containing compound is a hydrazine derivative having active hydrogen; and (b)
It is a surface-treated film formed by applying a silane coupling agent and (c) a surface-treating composition containing phosphoric acid and / or hexafluorometallic acid, and drying. This surface treatment film does not contain Cr at all.

First, the epoxy group-containing resin and active hydrogen-containing compound which form the water-dispersible resin or water-soluble resin as the component (a) will be described. As the epoxy group-containing resin, for example, epoxy resin, modified epoxy resin, acrylic copolymer resin copolymerized with an epoxy group-containing monomer, polybutadiene resin having an epoxy group,
The polyurethane resin having an epoxy group and the adduct or condensate of these resins may be used alone or in combination of two or more.

As the above-mentioned epoxy resin, polyphenols such as bisphenol A, bisphenol F and novolac type phenol are reacted with epihalohydrin such as epichlorohydrin to introduce a glycidyl group, or a reaction product obtained by introducing the glycidyl group into the reaction product. Furthermore, aromatic epoxy resins obtained by reacting polyphenols to increase the molecular weight; further, aliphatic epoxy resins, alicyclic epoxy resins and the like can be mentioned. These can be used alone or in combination of two or more. Can be used. It is preferable that these epoxy resins have a number average molecular weight of 1500 or more, particularly when film forming properties at low temperatures are required. Examples of the modified epoxy resin include resins obtained by reacting various modifying agents with the epoxy groups or hydroxyl groups in the epoxy resin. Examples thereof include epoxy ester resins obtained by reacting a drying oil fatty acid; acrylic acid or methacrylic acid. Examples thereof include an epoxy acrylate resin modified with a polymerizable unsaturated monomer component containing; and a urethane modified epoxy resin reacted with an isocyanate compound.

As the acrylic copolymer resin copolymerized with the above-mentioned epoxy group-containing monomer, the unsaturated monomer having an epoxy group and a polymerizable unsaturated monomer component containing acrylate or methacrylic acid ester as essential components are subjected to a solution polymerization method. , A resin synthesized by an emulsion polymerization method, a suspension polymerization method, or the like. Examples of the polymerizable unsaturated monomer component include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-, iso- or ter
C1 of acrylic acid or methacrylic acid such as t-butyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, decyl (meth) acrylate and lauryl (meth) acrylate
~ C24 alkyl ester; C1-4 of acrylic acid, methacrylic acid, styrene, vinyltoluene, acrylamide, acrylonitrile, N-methylol (meth) acrylamide, N-methylol (meth) acrylamide
Examples thereof include alkyl ether compounds; N, N-diethylaminoethyl methacrylate and the like. As the unsaturated monomer having an epoxy group, glycidyl methacrylate, glycidyl acrylate, 3,4-epoxycyclohexyl-1-methyl (meth) acrylate, or the like having an epoxy group and a polymerizable unsaturated group, It is not particularly limited. Further, the acrylic copolymer resin may be a resin modified with a polyester resin, an epoxy resin, a phenol resin, or the like.

Particularly preferable as the epoxy resin is a resin represented by the following chemical structural formula, which is a reaction product of bisphenol A and epiparohydrin, and is particularly preferable because it has excellent corrosion resistance.

[Chemical 1] In the above chemical structural formula, q is an integer of 0 to 50, preferably 1
It is an integer of -40, Most preferably, it is an integer of 2-20.
Such a bisphenol A type epoxy resin can be obtained by a production method widely known in the art.

Examples of the active hydrogen-containing compound which reacts with the epoxy group of the epoxy group-containing resin include the following.・ Hydrazine derivatives having active hydrogen ・ Primary or secondary amine compounds having active hydrogen ・ Organic acids such as ammonia and carboxylic acids ・ Hydrogen halides such as hydrogen chloride ・ Alcohols, thiols ・ Active hydrogen Quaternary chlorinating agent which is a hydrazine derivative which does not have or a mixture of a tertiary amine and an acid. In the present invention, one or more of these can be used, but in order to obtain excellent corrosion resistance, at least one active hydrogen-containing compound is used. Part (preferably all) must be a hydrazine derivative having active hydrogen.

The following can be mentioned as typical examples of the amine compound having activated hydrogen. (1) A primary amino group of an amine compound containing one secondary amino group such as diethylenetriamine, hydroxyethylaminoethylamine, ethylaminoethylamine, and methylaminopropylamine and one or more primary amino groups, a ketone, Aldehydes or carboxylic acids with eg 10
Aldimine is reacted by heating at a temperature of 0 to 230 ° C,
Compounds modified with ketimine, oxazoline or imidazoline; (2) secondary monoamines such as diethylamine, diethanolamine, di-n- or -ios-propanolamine, N-methylethanolamine, N-ethylethanolamine;

(3) A secondary amine-containing compound obtained by adding a monoalkanolamine such as monoethanolamine and a dialkyl (meth) acrylamide by a Michael addition reaction; (4) Monoethanolamine, neopentanol Amine,
2-aminopropanol, 3-aminopropanol, 2
A compound obtained by modifying the primary amine group of an alkanolamine such as hydroxy-2 '(aminopropoxy) ethyl ether into a ketimine;

The above-mentioned quaternary chlorinating agent which can be used as a part of the active hydrogen-containing compound is a hydrazine derivative having no active hydrogen or a tertiary amine, which is not reactive with an epoxy group by itself, and therefore these compounds are treated with an epoxy group. It is a mixture with an acid so that it can react with. The quaternary chlorinating agent reacts with the epoxy group in the presence of water, if necessary, to form a quaternary salt with the epoxy group-containing resin. The acid used to obtain the quaternary chlorinating agent may be any of organic acids such as acetic acid and lactic acid, and inorganic acids such as hydrochloric acid. The hydrazine derivative having no active hydrogen used for obtaining the quaternary chlorinating agent is, for example, 3,6-dichloropyridazine, and the tertiary amine is, for example, dimethylethanolamine, triethylamine, or the like. Examples include trimethylamine, triisopropylamine, methyldiethanolamine and the like.

It is the hydrazine derivative having active hydrogen that exhibits the most useful performance of the above active hydrogen-containing compounds and has excellent corrosion resistance. Specific examples of the hydrazine derivative having active hydrogen include the following. Carbohydrazide, propionic acid hydrazide, salicylic acid hydrazide, adipic acid dihydrazide, sebacic acid dihydrazide, dodecanoic acid dihydrazide, isophthalic acid dihydrazide, thiocarbohydrazide, 4,4'-oxybisbenzenesulfonyl hydrazide, benzophenone hydrazone, aminopolyacrylamide, etc. Compounds; pyrazole compounds such as pyrazole, 3,5-dimethylpyrazole, 3-methyl-5-pyrazolone, and 3-amino-5-methylpyrazole;

1,2,4-triazole, 3-amino-1,2,4-triazole, 4-amino-1,2,
4-triazole, 3-mercapto-1,2,4-triazole, 5-amino-3-mercapto-1,2,4-
Triazole, 2,3-dihydro-3-oxo-1,
2,4-triazole, 1H-benzotriazole, 1
-Hydroxybenzotriazole (monohydrate), 6-methyl-8-hydroxytriazolopyridazine, 6-phenyl-8-hydroxytriazolopyridazine, 5-hydroxy-7-methyl-1,3,8-triazindole Triazole compounds such as lysine;

5-phenyl-1,2,3,4-tetrazole, 5-mercapto-1-phenyl-1,2,
Tetrazole compounds such as 3,4-tetrazole; 5-Amino-2-mercapto-1,3,4-thiadiazole, 2,5-dimercapto-1,3,4-thiadiazole and other thiadiazole compounds; maleic hydrazide, 6- Pyridazine compounds such as methyl-3-pyridazone, 4,5-dichloro-3-pyridazone, 4,5-dibromo-3-pyridazone, 6-methyl-4,5-dihydro-3-pyridazone; and also among these Pyrazole compounds and triazole compounds having a 5-membered or 6-membered cyclic structure and having a nitrogen atom in the cyclic structure are particularly preferable. These hydrazine derivatives may be used alone or in combination of two or more.

The water-dispersible resin or water-soluble resin of (a) above, which is a reaction product of an epoxy group-containing resin and an active hydrogen-containing compound consisting of a hydrazine derivative having a part or all of active hydrogen, has an epoxy group The content of the resin and the specific active hydrogen-containing compound are 10 to 300 ° C., preferably 5
It can be obtained by reacting at 0 to 150 ° C. for about 1 to 8 hours.

This reaction may be carried out by adding an organic solvent, and the type of organic solvent used is not particularly limited. For example, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, dibutyl ketone, and cyclohexanone; ethanol, butanol, 2-ethylhexyl alcohol, benzyl alcohol, ethylene glycol,
Ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, propylene glycol, propylene glycol monomethyl ether, diethylene glycol, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, and other hydroxyl group-containing alcohols and ethers; ethyl acetate, Examples thereof include esters such as butyl acetate and ethylene glycol monobutyl ether acetate; aromatic hydrocarbons such as toluene and xylene. One or more of these can be used. Of these, ketone-based or ether-based solvents are particularly preferable from the viewpoints of solubility with epoxy resin and film-forming property.

The compounding ratio of the epoxy group-containing resin and the active hydrogen-containing compound consisting of a hydrazine derivative having a part or all of active hydrogen is such that the ratio of the number of active hydrogen groups to the number of epoxy groups [number of active hydrogen groups / epoxy Cardinality] from 0.01 to
From the viewpoint of corrosion resistance, water dispersibility, etc., it is suitable to set it to 10, more preferably 0.1 to 8, and even more preferably 0.2 to 4.

The proportion of the hydrazine derivative having active hydrogen in the active hydrogen-containing compound is 10 to 100 mol%, more preferably 30 to 100 mol%, and further preferably 40 to 100 mol%. . If the proportion of the hydrazine derivative having active hydrogen is less than 10 mol%, the surface-treated coating cannot be provided with a sufficient rust preventive function, and the obtained rust preventive effect is obtained by simply mixing the film forming organic resin and the hydrazine derivative. It is almost the same as when you did.
In the present invention, the water-dispersible resin of (a) above, which is a reaction product of the epoxy group-containing resin obtained as described above and an active hydrogen-containing compound which is partially or wholly composed of a hydrazine derivative having active hydrogen. Alternatively, one type of water-soluble resin may be used alone or two or more types may be mixed and used.

In the present invention, in order to form a dense barrier film, it is desirable to mix a curing agent in the resin composition and heat-cure the film. As a curing method for forming a film of the resin composition, (1) a curing method utilizing a urethane-forming reaction between an isocyanate and a hydroxyl group in the base resin, (2) selected from melamine, urea and benzoguanamine 1 to 5 carbon atoms in part or all of the methylol compound obtained by reacting one or more of formaldehyde
The curing method utilizing the etherification reaction between the alkyl etherified amino resin obtained by reacting the monohydric alcohol with the hydroxyl group in the base resin is suitable. It is particularly preferable to use the urethanization reaction as the main reaction.

The polyisocyanate compound used in the curing method (1) above is an aliphatic, alicyclic (including heterocyclic) or aromatic isocyanate compound having at least two isocyanate groups in one molecule, or an aromatic isocyanate compound thereof. It is a compound obtained by partially reacting a compound with a polyhydric alcohol. Examples of such polyisocyanate compounds include the following.

M- or p-phenylene diisocyanate, 2,4- or 2,6-tolylene diisocyanate, o- or p-xylylene diisocyanate, hexamethylene diisocyanate, dimer acid diisocyanate, isophorone diisocyanate The above compounds alone or Mixtures and polyhydric alcohols (dihydric alcohols such as ethylene glycol and propylene glycol; trihydric alcohols such as glycerin and trimethylolpropane; tetrahydric alcohols such as pentaerythritol; hexahydric alcohols such as sorbitol and dipentaerythritol) Which is a reaction product of at least two isocyanates in one molecule, and these polyisocyanate compounds are used alone or in combination of two or more. Kill.

Examples of the protective agent (blocking agent) for the polyisocyanate compound include aliphatic monoalcohols such as methanol, ethanol, propanol, butanol and octyl alcohol; monoethers of ethylene glycol and / or diethylene glycol, for example, , Methyl, ethyl, propyl (n-, iso), butyl (n-, iso, se)
c) and other monoethers; aromatic alcohols such as phenol and cresol; oximes such as acetoxime and methyl ethyl ketone oxime; and the like can be used. By reacting one or more of these with the polyisocyanate compound, It is possible to obtain a polyisocyanate compound that is stably protected at least at room temperature.

Such a polyisocyanate compound (a
2) is the reaction product (a) of the epoxy group-containing resin and the specific active hydrogen-containing compound (that is, the water-dispersible resin and / or the water-soluble resin that is the component of (a) above), As curing agent (a) / (a2) = 95 / 5-5
5/45 (weight ratio of nonvolatile content), preferably (a) /
(A2) = 90/10 to 65/35 is suitable for blending. The polyisocyanate compound has water absorption property, and if it is mixed in excess of (a) / (a2) = 55/45, the adhesion of the surface-treated film will be deteriorated. Furthermore, when topcoating is performed on the surface-treated film, the unreacted polyisocyanate compound migrates into the coating film, causing inhibition of curing of the coating film and poor adhesion. From this point of view, it is preferable that the compounding amount of the polyisocyanate compound (a2) is (a) / (a2) = 55/45 or less.

The water-dispersible resin and / or the water-soluble resin, which is a reaction product of the epoxy group-containing resin and the above-mentioned specific active hydrogen-containing compound, can be sufficiently added by adding the above-mentioned crosslinking agent (curing agent). Although it crosslinks, it is desirable to use a known curing accelerating catalyst in order to further increase low temperature crosslinkability. Examples of this curing acceleration catalyst include N-
Ethylmorpholine, dibutyltin dilaurate, cobalt naphthenate, stannous chloride, zinc naphthenate, bismuth nitrate and the like can be used. Further, for the purpose of slightly improving the physical properties such as the adhesiveness, a known resin such as acryl, alkyd or polyester may be mixed and used together with the epoxy group-containing resin.

In order to disperse or solubilize the reaction product of the epoxy group-containing resin and the specific active hydrogen-containing compound in water,
For example, the following method can be adopted. A method of reacting an epoxy group of an epoxy group-containing resin with a dibasic acid or a secondary amine that is an active hydrogen-containing compound, neutralizing with a neutralizing agent such as a tertiary amine, acetic acid or phosphoric acid, and water-dispersing the epoxy resin. And a method in which a modified epoxy resin (a3) obtained by reacting an end hydroxyl group-containing polyalkylene oxide such as polyethylene glycol or polypropylene glycol with an isocyanate is used as a dispersant and is water-dispersed. Method using both of the above

When the above-mentioned methods are adopted, the reaction product (a) of the epoxy group-containing resin and the specific active hydrogen-containing compound (that is, the water-dispersible resin and / or the water-soluble resin which is the component of (a) above) is used. Resin) and the modified epoxy resin (a3) are (a) / (a3) = 90/5 to 60/40
(Weight ratio of nonvolatile components), preferably (a) / (a3) =
It is suitable to mix in the ratio of 80/20 to 65/35. The compounding ratio of the above reaction product (a) is (a) / (a3)
= 90/5, good dispersibility of the resin cannot be obtained,
The desired performance cannot be obtained because the resin particles become coarse and defects occur during film formation. Further, if the compounding ratio of the modified epoxy resin (a3) exceeds (a) / (a3) = 60/40, problems such as deterioration of corrosion resistance due to excessive hydrophilicity occur.

In the surface treatment composition, in addition to the above specific water-dispersible resin and / or water-soluble resin, other water-dispersible resin and / or water-soluble resin may be used, for example,
15 mass% of one or more kinds of acrylic resin, urethane resin, polyester resin, epoxy resin, ethylene resin, alkyd resin, phenol resin, olefin resin, etc. in the total resin solid content. You may mix | blend with a grade as an upper limit.

As the water-dispersible resin which is the component (a), a specific polyalkylene glycol-modified epoxy resin (A) and an epoxy group-containing resin (B) other than the polyalkylene glycol-modified epoxy resin (A) are used. ), A hydrazine derivative (C) having active hydrogen, and optionally an active hydrogen-containing compound (D) other than this hydrazine derivative (C) are reacted to obtain an aqueous epoxy resin dispersion (X). By using, it is possible to obtain particularly excellent white rust resistance.

The polyalkylene glycol-modified epoxy resin (A) was obtained by reacting a polyalkylene glycol having a number average molecular weight of 400 to 20,000, a bisphenol type epoxy resin, an active hydrogen-containing compound and a polyisocyanate compound. It is a thing. As the polyalkylene glycol, for example, polyethylene glycol, polypropylene glycol, polybutylene glycol, etc. can be used, and among them, polyethylene glycol is particularly preferable. The number average molecular weight of the polyalkylene glycol is suitably in the range of 400 to 20,000, preferably 500 to 10,000, from the viewpoint of the water dispersibility of the resulting resin, storability and the like. The bisphenol-type epoxy resin is a bisphenol-based compound having at least one epoxy group in one molecule, and in particular, a bisphenol diene compound obtained by a condensation reaction between a bisphenol-based compound and epihalohydrin (eg, epichlorohydrin). Glycidyl ether is preferable because a film excellent in flexibility and anticorrosion can be easily obtained.

Representative examples of the bisphenol compound that can be used for preparing the bisphenol type epoxy resin are bis (4-hydroxyphenyl) -2,2-propane and bis (4-hydroxyphenyl) -1,1-. Ethane, bis (4-hydroxyphenyl) -methane, 4,
4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenyl sulfone, bis (4-hydroxyphenyl) -1,1-isobutane, bis (4-hydroxy-3-t-butylphenyl) -2,2-propane, etc. Can be mentioned. Among the epoxy resins prepared using such bisphenol compounds, bisphenol A
The type epoxy resin is particularly preferable in that a film excellent in flexibility and corrosion resistance can be obtained. Further, the bisphenol type epoxy resin is generally about 310 to 10,000, particularly preferably about 3 from the viewpoint of production stability during production of the polyalkylene glycol-modified epoxy resin.
It preferably has a number average molecular weight of from 20 to 2000, and an epoxy equivalent weight in the range of from about 155 to 5000, particularly preferably from about 160 to 1000.

The active hydrogen-containing compound is used for blocking the isocyanate group in the polyalkylene glycol-modified epoxy resin (A). Typical examples thereof include monohydric alcohols such as methanol, ethanol and diethylene glycol monobutyl ether; monovalent carboxylic acids such as acetic acid and propionic acid; and monovalent thiols such as ethyl mercaptan. Other blocking agents (active hydrogen-containing compounds) include secondary amines such as diethylamine; one secondary amino group or hydroxyl group such as diethylenetriamine and monoethanolamine, and one or more primary groups. A compound in which the primary amino group of an amine compound containing an amino group is modified into an aldimine, ketimine, oxazoline or imidazoline by heating reaction with a ketone, aldehyde or carboxylic acid at a temperature of, for example, 100 to 230 ° C; methylethylketoxime And oximes; phenols such as phenol and nonylphenol, and the like. It is preferred that these compounds generally have a number average molecular weight in the range of 30 to 2000, particularly preferably 30 to 200.

The above-mentioned polyisocyanate compound is a compound having two or more, preferably two or three, isocyanate groups in one molecule, and those generally used in the production of polyurethane resins can be similarly used. Such polyisocyanate compounds include aliphatic, alicyclic and aromatic polyisocyanate compounds. Typical examples are hexamethylene diisocyanate (HMDI), HMDI biuret compound,
Aliphatic polyisocyanate compounds such as isocyanurate compounds of HMDI; isophorone diisocyanate (IPDI), biuret compounds of IPDI, IPDI
And an alicyclic polyisocyanate compound such as hydrogenated xylylene diisocyanate and hydrogenated 4,4′-diphenylmethane diisocyanate; and an aromatic polyisocyanate compound such as tolylene diisocyanate and xylylene diisocyanate.

The mixing ratio of each component during the production of the polyalkylene glycol-modified epoxy resin (A) is generally appropriate within the following range. That is, the equivalent ratio of the hydroxyl group of the polyalkylene glycol to the isocyanate group of the polyisocyanate compound is 1 / 1.2-1 to 1/1.
0, preferably 1 / 1.5 to 1/5, particularly preferably 1
It is suitable to set it to /1.5 to 1/3. The equivalent ratio of the hydroxyl group of the active hydrogen-containing compound to the isocyanate group of the polyisocyanate compound is 1/2 to 1/100, preferably 1/3 to 1/50, particularly preferably 1/3 to 1 /.
A value of 20 is suitable. The equivalent ratio of the total amount of the hydroxyl groups of the polyalkylene glycol, the bisphenol type epoxy resin and the active hydrogen-containing compound to the isocyanate group of the polyisocyanate compound is 1 / 1.5 or less, preferably 1 / 0.1 to 1/1. .5, particularly preferably 1 /
It is suitable to be 0.1 to 1 / 1.1.

The reaction of the above polyalkylene glycol, bisphenol type epoxy resin, active hydrogen containing compound and polyisocyanate compound can be carried out by a known method. The polyalkylene glycol-modified epoxy resin (A) obtained above, an epoxy group-containing resin (B) other than the polyalkylene glycol-modified epoxy resin (A), and a hydrazine derivative (C) having active hydrogen.
And an active hydrogen-containing compound (D) other than the hydrazine derivative (C), if necessary, can be easily dispersed in water and have good adhesion to the material. The dispersion liquid (X) can be obtained.

As the epoxy group-containing resin (B) other than the above polyalkylene glycol-modified epoxy resin (A), polyphenols such as bisphenol A, bisphenol F and novolac type phenol are reacted with epihalohydrin such as epichlorohydrin to form a glycidyl group. Or an aromatic epoxy resin obtained by further reacting this glycidyl group-introduced reaction product with a polyphenol to increase the molecular weight; and further, an aliphatic epoxy resin, an alicyclic epoxy resin and the like. One of these may be used alone, or two or more thereof may be mixed and used. These epoxy resins have a number average molecular weight of 150, especially when film forming properties at low temperatures are required.
It is preferably 0 or more. Examples of the epoxy group-containing resin (B) include resins obtained by reacting various modifying agents with the epoxy groups or hydroxyl groups in the epoxy group-containing resin, for example, epoxy ester resin obtained by reacting a drying oil fatty acid. An epoxy acrylate resin modified with a polymerizable unsaturated monomer component containing acrylic acid or methacrylic acid; and a urethane modified epoxy resin reacted with an isocyanate compound.

Further, as the epoxy group-containing resin (B), an unsaturated monomer having an epoxy group and a polymerizable unsaturated monomer component essentially containing acrylic acid ester or methacrylic acid ester are used in a solution polymerization method, an emulsion polymerization method or a suspension polymerization method. An acrylic copolymer resin copolymerized with an epoxy group-containing monomer synthesized by a turbid polymerization method or the like can be mentioned, and as the polymerizable unsaturated monomer component,
For example, methyl (meth) acrylate, ethyl (meth)
Acrylate, propyl (meth) acrylate, n-,
C1-C24 alkyl ester of acrylic acid or methacrylic acid such as iso- or tert-butyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, decyl (meth) acrylate and lauryl (meth) acrylate. Acrylic acid, methacrylic acid, styrene, vinyltoluene,
Acrylonitrile, acrylonitrile, N-methylol (meth) acrylamide, C1-4 alkyl ether compound of N-methylol (meth) acrylamide; N, N-
Examples thereof include diethylaminoethyl methacrylate. In addition, as the unsaturated monomer having an epoxy group, glycidyl methacrylate, glycidyl acrylate, 3,4 epoxycyclohexyl-1-methyl (meth) acrylate, etc. are particularly preferable as long as they have an epoxy group and a polymerizable unsaturated group. It is not limited. The acrylic copolymer resin is a polyester resin,
A resin modified with an epoxy resin, a phenol resin, or the like can also be used.

Particularly preferable as the epoxy group-containing resin (B) is a resin represented by the following chemical structural formula, which is a reaction product of bisphenol A and epiparohydrin, and is particularly preferable because it has excellent corrosion resistance. .

[Chemical 2] In the above chemical structural formula, q is an integer of 0 to 50, preferably 1
It is an integer of -40, Most preferably, it is an integer of 2-20.
Such a bisphenol A type epoxy resin can be obtained by a production method widely known in the art.

Examples of the active hydrogen-containing compound that reacts with the epoxy group of the epoxy group-containing resin (B) include the following, and the details thereof are as described above. -Hydrazine derivatives having active hydrogen-Primary or secondary amine compounds having active hydrogen-Organic acids such as ammonia and carboxylic acids-Hydrogen halides such as hydrogen chloride-Alcohols, thiols-Active hydrogen Quaternary chlorinating agent which is a mixture of a hydrazine derivative or a tertiary amine and an acid which does not have: When preparing the above aqueous epoxy resin dispersion (X),
One or more of these may be used, but in order to obtain excellent corrosion resistance, at least a part (preferably all) of the active hydrogen-containing compound needs to be a hydrazine derivative having active hydrogen. That is, among these, the hydrazine derivative (C) having active hydrogen is used as an essential component, and the active hydrogen-containing compound (D) other than the hydrazine derivative (C) is used as necessary.

The polyalkylene glycol-modified epoxy resin (A) as described above, the epoxy group-containing resin (B) other than the polyalkylene glycol-modified epoxy resin (A), and the hydrazine derivative (C) having active hydrogen.
And optionally an active hydrogen-containing compound (D) other than the hydrazine derivative (C), preferably 10 to
About 1 at a temperature of 300 ° C, more preferably 50-150 ° C.
The aqueous epoxy resin dispersion (X) described above can be obtained by reacting for ~ 8 hours and dispersing the resin thus obtained in water.

The above reaction may be carried out by adding an organic solvent, and the type of organic solvent used is not particularly limited. For example, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, dibutyl ketone, and cyclohexanone; ethanol, butanol, 2-ethylhexyl alcohol, benzyl alcohol, ethylene glycol,
Ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, propylene glycol, propylene glycol monomethyl ether, diethylene glycol, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, and other hydroxyl group-containing alcohols and ethers; ethyl acetate, Examples thereof include esters such as butyl acetate and ethylene glycol monobutyl ether acetate; aromatic hydrocarbons such as toluene and xylene. One or more of these can be used. Of these, ketone-based or ether-based solvents are particularly preferable from the viewpoint of solubility with epoxy resin, film forming property, and the like.

The mixing ratio of the polyalkylene glycol-modified epoxy resin (A), the epoxy group-containing resin (B) other than the polyalkylene glycol-modified epoxy resin (A), and the hydrazine derivative (C) having active hydrogen is The equivalent ratio of the active hydrogen groups in the hydrazine derivative (C) to the epoxy groups in the alkylene glycol-modified epoxy resin (A) and the epoxy group-containing resin (B) is 0.01 to.
10, preferably 0.1-8, more preferably 0.2
It is suitable to set it to 4 from the viewpoint of corrosion resistance and water dispersibility of the resin. Further, a part of the hydrazine derivative (C) having active hydrogen can be replaced with the active hydrogen-containing compound (D), but the replacement amount is 90 mol% or less, preferably 70 mol% or less, more preferably 10 to From the viewpoint of anticorrosion property and adhesiveness, it is suitable to set the content within the range of 60 mol%.

Further, in order to form a dense barrier film, it is desirable to mix a curing agent in the aqueous epoxy resin dispersion liquid (X) and heat-cure the film. As a curing method for forming a film of the resin composition, (1) a curing method utilizing a urethane-forming reaction between an isocyanate and a hydroxyl group in the base resin, (2) selected from melamine, urea and benzoguanamine Etherification reaction between an alkyl etherified amino resin obtained by reacting a part or all of a methylol compound obtained by reacting one or more kinds of formaldehyde with a monohydric alcohol having 1 to 5 carbon atoms and a hydroxyl group in a base resin Although a curing method utilizing the above is suitable, it is particularly preferable to make the urethane reaction of isocyanate and the hydroxyl group in the base resin the main reaction.

The polyisocyanate compound as a curing agent that can be used in the curing method (1) above is an aliphatic compound having at least two isocyanate groups in one molecule,
It is an alicyclic (including heterocyclic) or aromatic isocyanate compound, or a compound obtained by partially reacting these compounds with a polyhydric alcohol. Specific examples of such a polyisocyanate compound are as described above, and one kind of these polyisocyanate compounds can be used alone or two or more kinds can be mixed and used. Further, specific examples of the protective agent (blocking agent) for the polyisocyanate compound are also as described above, and by reacting one or more of them with the polyisocyanate compound, stable at least at room temperature. It is possible to obtain a polyisocyanate compound as a protected curing agent.

Such a polyisocyanate compound (a
2) is a reaction product (a1) of the components (A), (B) and (C) (and optionally the component (D)) (ie, water which is the component (a)). (A1) / (a2) = 95 / as a curing agent for the dispersible resin)
5 to 55/45 (mass ratio of nonvolatile content), preferably (a
It is suitable to mix in the ratio of 1) / (a2) = 90/10 to 65/35. The polyisocyanate compound has water absorption property, and if it is mixed in excess of (a1) / (a2) = 55/45, the adhesion of the surface-treated film will be deteriorated. Furthermore, when topcoating is performed on the surface-treated film, the unreacted polyisocyanate compound migrates into the coating film, causing inhibition of curing of the coating film and poor adhesion. From this point of view, the polyisocyanate compound (a2)
It is preferable that the compounding amount of (a1) / (a2) = 55/45 or less.

The water-dispersible resin, which is a reaction product of the above-mentioned components (A), (B) and (C) (and optionally the above-mentioned component (D)), contains the above-mentioned crosslinking agent. Although it is sufficiently crosslinked by the addition of (curing agent), it is desirable to use a known curing accelerating catalyst in order to further increase the low temperature crosslinking property. Examples of this curing acceleration catalyst include N-
Ethylmorpholine, dibutyltin dilaurate, cobalt naphthenate, stannous chloride, zinc naphthenate, bismuth nitrate and the like can be used. Further, for the purpose of slightly improving the physical properties such as the adhesiveness, a known resin such as acryl, alkyd or polyester may be mixed and used together with the epoxy group-containing resin.

Next, the silane coupling agent which is the component (b) will be described. Examples of the silane coupling agent include vinylmethoxysilane, vinylethoxysilane, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, and β- (3.
4 epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ
-Glycidoxypropylmethyldiethoxysilane, γ-
Glycidoxypropyltriethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethylamine Excisilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane,
γ-methacryloxypropylmethyldimethoxysilane,
γ-methacryloxypropyltrimethoxysilane, γ-
Methacryloxypropylmethyldiethoxysilane, γ-
Methacryloxypropyltriethoxysilane, γ-mercaptopropylmethyldimethoxysilane, γ-mercaptopropyltrimethoxysilane, p-styryltrimethoxysilane, γ-acryloxypropyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane , Γ-ureidopropyltriethoxysilane, γ
-Chloropropyltrimethoxysilane, bis (triethoxysilylpropyl) tetrasulfide, γ-isocyanatopropyltriethoxysilane, γ-triethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine, N- (vinylbenzyl) Amine) -β-aminoethyl-γ-aminopropyltrimethoxysilane and the like, and one of these may be used alone, or two or more thereof may be used in combination.

In the present invention, the reason as described above is considered that the white rust resistance is improved by the surface treatment composition containing the silane coupling agent together with the specific acid component. Further, among the above silane coupling agents,
From the viewpoint of having a functional group having high reactivity with the water-dispersible resin and / or the water-soluble resin (a), a silane coupling agent having an amino group as a reactive functional group is particularly preferable. As such a silane coupling agent,
For example, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropyltrimexisilane, γ-amino Examples thereof include propyltrimethoxysilane and γ-aminopropyltriethoxysilane. Specifically, Shin-Etsu Chemical Co., Ltd.'s KBM-903, KBE-903, and KBM.
-603, KBE-602, KBE-603 (all are trade names) and the like can be used.

The compounding amount of the silane coupling agent is 1 to 300 parts by weight based on 100 parts by weight of the solid content of the water-dispersible resin and / or the water-soluble resin which is the component (a).
Preferably 5 to 100 parts by weight, more preferably 15 to
50 parts by weight is suitable. If the compounding amount of the silane coupling agent is less than 1 part by weight, the corrosion resistance is poor, while 3
If it exceeds 100 parts by weight, a sufficient film cannot be formed,
The effect of enhancing the adhesiveness and the barrier property with the water-dispersible resin and / or the water-soluble resin cannot be exhibited, and the corrosion resistance decreases.

Next, phosphoric acid and / or hexafluorometallic acid, which is the component (c), has an action of acting on the inactive plated metal surface to activate the plated metal surface. The phosphoric acid and hexafluorometal acid may be used alone or in combination. The type of hexafluorometal acid is not particularly limited, but especially T such as fluorotitanic acid, fluorozirconic acid, and silicofluoric acid is used.
Hexafluorometalic acid containing one or more elements selected from i, Si and Zr is preferable, and one or more of these can be used.

The compounding amount of phosphoric acid and / or hexafluorometalic acid is 0.1 in total with respect to 100 parts by weight of the solid content of the water-dispersible resin and / or water-soluble resin as the component (a). It is suitable to be -80 parts by weight, preferably 1-60 parts by weight, more preferably 5-50 parts by weight. If the amount of phosphoric acid and / or hexafluorometallic acid is less than 0.1 parts by weight, the corrosion resistance is poor, while 8
If the amount exceeds 0 part by weight, uneven appearance after the film formation is likely to occur.

If necessary, a water-soluble phosphate may be added to the surface treatment composition for the purpose of improving corrosion resistance. As this water-soluble phosphate, for example, one or more metal salts such as orthophosphoric acid, pyrophosphoric acid, polyphosphoric acid, and metaphosphoric acid can be used. Further, one or more salts of organic phosphoric acid (eg, phytic acid, phytate, phosphonic acid, phosphonate and metal salts thereof) may be added. Further, among them, the primary phosphate is preferable in terms of stability of the surface treatment composition. There is no particular limitation on the form of phosphate present in the film, and it does not matter whether it is crystalline or amorphous. In addition, there are no particular restrictions on the ionicity or solubility of the phosphate in the film. It is considered that the reason why the corrosion resistance is improved by adding the water-soluble phosphate is that the water-soluble phosphate forms a dense and sparingly soluble compound during film formation.

As described above, the silane coupling agent chemically bonds with both the activated plating metal and the film-forming resin to obtain excellent adhesion and corrosion resistance between the plating metal and the film-forming resin. However, the surface of the plated metal inevitably has an inactive portion, and at such an inactive site, the above chemical bond is less likely to occur and the rust preventive effect cannot be sufficiently exhibited. The water-soluble phosphate forms a dense and sparingly soluble compound in the portion of such a plating film when the film is formed.
That is, when the plating film is dissolved by the phosphate ion of the water-soluble phosphate, p at the plating film / surface treatment composition interface
H increases, and as a result, a water-soluble phosphate precipitate film is formed, which contributes to the improvement of corrosion resistance.

From the viewpoint of obtaining particularly excellent corrosion resistance, Al is used as the cation species of the water-soluble phosphate.
Mn, Ni, and Mg are particularly desirable, and it is preferable to use a water-soluble phosphate containing one or more elements selected from these. Examples of such water-soluble phosphates include aluminum monophosphate, manganese monophosphate, nickel monophosphate, and magnesium monophosphate. Of these, aluminum monophosphate is particularly preferable. Is most preferred. The molar ratio of the cationic component and _P 2 _{O 5} component [cation] _{/ [P} 2 _{O 5]} is preferably from 0.4 to 1.0. Molar ratio [cation] / [P
₂ O ₅ ] of less than 0.4 is not preferable because the soluble phosphoric acid impairs the poor solubility of the film and reduces the corrosion resistance. On the other hand, when it exceeds 1.0, the stability of the treatment liquid is significantly lost, which is not preferable.

The content of the water-soluble phosphate is 0.1 to 100 parts by weight of the solid content of the water-dispersible resin and / or the water-soluble resin as the component (a).
It is suitable that the amount is 60 parts by weight, preferably 0.5 to 40 parts by weight, and more preferably 1 to 30 parts by weight. If the amount of the water-soluble phosphate compounded is less than 0.1 part by weight, the effect of improving the corrosion resistance is not sufficient, while if it exceeds 60 parts by weight, the pH of the treatment liquid decreases and the reactivity becomes strong, resulting in uneven appearance. It tends to occur.

The surface treatment composition may optionally contain a non-chromium type rust preventive additive for the purpose of improving corrosion resistance. By incorporating such a non-chromium-based anticorrosive additive in the surface treatment composition, particularly excellent anticorrosion performance (self-repairing property) can be obtained. It is preferable to use one or more selected from the following groups (e1) to (e5) as the non-chromium rust preventive additive. (E1) Silicon oxide (e2) Calcium or calcium compound (e3) Slightly soluble phosphoric acid compound (e4) Molybdic acid compound (e5) One selected from triazoles, thiols, thiadiazoles, thiazoles and thiurams The details and the anticorrosion mechanism of these non-chromium rust preventive additives (e1) to (e5) of organic compounds containing S atom are as follows.

First, as the component (e1), colloidal silica or dry silica which is fine particle silica can be used. From the viewpoint of corrosion resistance, calcium ion exchange silica having calcium bonded to its surface is particularly preferable. It is preferable to use. Examples of the colloidal silica include Snowtex O, 20, 3 manufactured by Nissan Chemical Industries, Ltd.
0, 40, C, S (all are trade names) can be used, and as fumed silica, AEROSIL R971, R812, R8 manufactured by Nippon Aerosil Co., Ltd.
11, R974, R202, R805, 130, 20
It is possible to use 0, 300, and 300CF (all are trade names). Further, as the calcium ion exchange silica, WR Grace & Co. SHIELDEX C303, manufactured by
SHIELDEX AC3, SHIELDEX AC5
(Both are trade names), SH manufactured by Fuji Silysia Chemical Ltd.
IELDEX, SHIELDEX SY710 (both are trade names) or the like can be used. These silicas contribute to the production of a dense and stable corrosion product of zinc in a corrosive environment, and the corrosion product is formed densely on the plating surface, thereby suppressing the promotion of corrosion.

The components (e2) and (e3) exhibit particularly excellent anticorrosion performance (self-repairing property) due to the precipitation effect. The calcium compound which is the component of (e2) above is
Any of calcium oxide, calcium hydroxide and calcium salt may be used, and one or more of these may be used. The type of calcium salt is not particularly limited, and single salts containing only calcium as a cation such as calcium silicate, calcium carbonate, and calcium phosphate, and calcium and calcium such as calcium / zinc phosphate and calcium / magnesium phosphate. You may use the double salt containing cations other than. In the component (e2), base metal calcium preferentially dissolves over zinc and aluminum, which are plating metals, in a corrosive environment, and this seals the defective portion as OH ⁻ generated by the cathode reaction and a dense and hardly soluble product. And suppresses the corrosion reaction. When it is mixed with silica as described above, calcium ions are adsorbed on the surface, electrically neutralize the surface charge and aggregate. As a result, a dense and sparingly soluble protective film is formed to block the corrosion and suppress the corrosion reaction.

As the sparingly soluble phosphoric acid compound (e3), a sparingly soluble phosphate can be used.
The sparingly soluble phosphate includes all kinds of salts such as simple salts and double salts. Further, the metal cation constituting it is not limited, and any metal cation such as sparingly soluble zinc phosphate, magnesium phosphate, calcium phosphate, and aluminum phosphate may be used. Further, there is no limitation on the skeleton or the degree of condensation of the phosphate ion, and it may be any of a normal salt, a dihydrogen salt, a monohydrogen salt or a phosphite, and the normal salt may be an orthophosphate or a polyphosphate. Includes all condensed phosphates such as salts. This sparingly soluble phosphorus compound, zinc or aluminum of the plating metal eluted by corrosion, forms a dense and sparingly soluble protective film by a complex formation reaction with phosphate ions dissociated by hydrolysis, blocking the corrosion starting point, Suppresses corrosion reaction.

As the molybdic acid compound (e4), for example, molybdate can be used. There is no limitation on the skeleton and the degree of condensation of the molybdate, and examples thereof include orthomolybdate, paramolybdate, and metamolybdate. Further, it includes all salts such as single salt and double salt, and examples of the double salt include molybdate phosphate. The molybdic acid compound exhibits self-repairing property due to the passivating effect. That is, in a corrosive environment, a dense oxide is formed on the surface of the plating film together with dissolved oxygen to block the corrosion starting point and suppress the corrosion reaction.

Examples of the organic compound (e5) include the following compounds.
That is, as triazoles, 1,2,4-triazole, 3-amino-1,2,4-triazole, 3
-Mercapto-1,2,4-triazole, 5-amino-3-mercapto-1,2,4-triazole, 1H-
Benzotriazole and the like, and as thiols,
1,3,5-triazine-2,4,6-trithiol,
2-Mercaptobenzimidazole and the like, and as thiadiazoles, 5-amino-2-mercapto-
1,3,4-thiadiazole, 2,5-dimercapto-
1,3,4-thiadiazole and the like, thiazoles such as 2-N, N-diethylthiobenzothiazole and 2-mercaptobenzothiazoles, and thiurams such as tetraethylthiuram disulfide. To be These organic compounds exhibit self-repairing properties due to the adsorption effect. That is, zinc or aluminum eluted by corrosion is adsorbed to a polar group containing sulfur contained in these organic compounds to form an inactive film, thereby blocking the corrosion starting point and suppressing the corrosion reaction.

The amount of the non-chromium rust preventive additive added is 0.1 to 10 parts by weight based on 100 parts by weight of the solid content of the water-dispersible resin and / or the water-soluble resin as the component (a).
It is suitable to be 50 parts by weight, preferably 0.5 to 30 parts by weight, more preferably 1 to 20 parts by weight. If the compounding amount of this non-chromium rust preventive additive is less than 0.1 part by weight,
The effect of improving corrosion resistance after alkali degreasing is not sufficiently obtained,
On the other hand, if it exceeds 50 parts by weight, not only the coatability and workability are deteriorated, but also the corrosion resistance is deteriorated, which is not preferable. It should be noted that two or more kinds of the above-mentioned rust preventive additives (e1) to (e5) may be added in combination, and in this case, a unique anticorrosive action is combined, so that higher corrosion resistance can be obtained. In particular, calcium ion-exchanged silica is used as the component (e1), and one or more of the components (e3), (e4), and (e5) are used, and particularly preferably the components (e3) to (e5) are used. Particularly excellent corrosion resistance is obtained when all of them are added together.

If necessary, a solid lubricant may be added to the surface treatment composition for the purpose of improving the processability of the coating. Examples of the solid lubricant include the following. (1) Polyolefin wax, paraffin wax: for example, polyethylene wax, synthetic paraffin, natural paraffin, microwax, chlorinated hydrocarbon, etc. (2) Fluororesin fine particles: For example, polyfluoroethylene resin (polytetrafluoroethylene resin, etc.) , Polyvinyl fluoride resin, polyvinylidene fluoride resin, etc.

In addition to these, fatty acid amide compounds (eg stearic acid amide, palmitic acid amide, methylene bis stearamide, ethylene bis stearamide,
Oleic acid amide, esyl acid amide, alkylene bis fatty acid amide, etc.), metallic soaps (eg, calcium stearate, lead stearate, calcium laurate, calcium palmitate, etc.), metallic sulfides (eg, molybdenum disulfide, tungsten disulfide). Etc.), graphite, fluorinated graphite, boron nitride, polyalkylene glycol, alkali metal sulfate, etc. may be used.

Among the above solid lubricants, polyethylene wax and fluororesin compounds (among others, polytetrafluoroethylene resin fine particles) are preferable. As polyethylene wax, Ceridust 96 manufactured by Hoechst
15A, 3715, 3620, 3910 (all are trade names), Sun Wax 131-P, 1 manufactured by Sanyo Kasei Co., Ltd.
61-P (all are trade names), Chemipearl W-100, W-200, W-500, W- manufactured by Mitsui Petrochemical Co., Ltd.
800, W-950 (both are trade names) or the like can be used.

As the fluororesin fine particles, tetrafluoroethylene fine particles are particularly preferable, and Daikin Industries, Ltd.
Lubron L-2 and L-5 (both are trade names), MP1100 and 1200 (both are trade names) manufactured by Mitsui DuPont, and full-on dispersions AD1 and AD2 manufactured by Asahi IC Eye Fluoropolymers Co., Ltd. Full on L1
40J, L150J, L155J (all are trade names) and the like are suitable. Further, among these, a particularly excellent lubricating effect can be expected by the combined use of polyolefin wax and tetrafluoroethylene. The blending amount of solid lubricant is
The solid content is 1 to 100 parts by weight of the solid content of the water-dispersible resin and / or the water-soluble resin as the component (a).
Amounts of 50 parts by weight, preferably 3 to 30 parts by weight are suitable. If the blending amount of the lubricant as the component (a) is less than 1 part by weight, the lubricating effect is poor, while if it exceeds 80 parts by weight, the coating property is deteriorated.

In the surface treatment film (and the surface treatment composition), other oxide fine particles (eg, aluminum oxide, zirconium oxide, titanium oxide, cerium oxide, antimony oxide) and phosphorus are used as corrosion inhibitors. Molybdates (eg, aluminum phosphomolybdate), organic phosphoric acids and their salts (eg, phytic acid,
Phytates, phosphonic acids, phosphonates and their metal salts, alkali metal salts, alkaline earth metal salts, etc.), organic inhibitors (eg hydrazine and its derivatives, thiol compounds, thiocarbamate salts, etc.)
One or two or more of the above can be added.

Further, if necessary, an organic color pigment (for example, a condensed polycyclic organic pigment, a phthalocyanine organic pigment, etc.), a color dye (for example, a pigment) may be added as an additive in the surface treatment film (and the surface treatment composition). , Water-soluble azo metal dyes, etc.), inorganic pigments (eg titanium oxide etc.), conductive pigments (eg metal powders of zinc, aluminum, nickel etc., iron phosphide, antimony doped tin oxide etc.),
One or two coupling agents (eg, titanium coupling agents), melamine / cyanuric acid adducts, etc.
More than one species can be added.

The surface treatment film formed by the surface treatment composition containing the above components has a dry film thickness of 0.02 to 0.02.
The thickness is 5 μm, preferably 0.05 to 5 μm, more preferably 0.3 to 3 μm, and further preferably 0.5 to 2 μm. If the dry film thickness is less than 0.02 μm, the corrosion resistance is insufficient, while if it exceeds 5 μm, the conductivity and workability are deteriorated. Further, an organic resin film can be formed as a second layer film on the upper layer of the surface treatment film described above. In this case, the film thickness of the organic resin film which is the second layer film is 0.0
2 μm or more and less than 5 μm, preferably 0.05 μm or more 5
The thickness of the surface treatment film, which is the first layer film, is 0.02 μm or more and less than 5 μm, preferably 0.05 μm or more and less than 5 μm, and the total thickness of both films does not exceed 5 μm. It is preferable.

Next, the specific film structure of the above-mentioned surface-treated film will be described. In the present invention, the film structure of the surface treatment film formed on the surface of the zinc-based plated steel sheet or the aluminum-based plated steel sheet has an amorphous compound layer containing P, Zn or / and Al, and O, and hydrazine as the upper layer. An organic resin matrix layer having a derivative-modified epoxy group-containing resin as a matrix, preferably P, Zn or / and Al in a film (amorphous compound layer and / or organic resin matrix layer). And a precipitation compound containing O, more preferably P, Zn or / and a precipitation compound containing Al, Si and O. This surface treatment film is C
r is not included at all.

In order to impart excellent corrosion resistance (white rust resistance) to a base plated steel sheet such as a zinc-based plated steel sheet by a chromium-free film, as described above, the organic resin serves as a diffusion barrier of corrosion factors. It forms an advanced barrier layer and suppresses the cathode reaction. A dense inert layer (reaction layer) is formed on the plating film surface layer by the reaction between the surface treatment composition and the plating film surface layer,
The anode reaction is suppressed by the inactivating action of the surface of the plating film by this inactive layer. Is more effective, and more preferably, it reacts with the defective portion (or damaged portion) of the above-mentioned inactive layer to repair it, and traps / makes insoluble the metal ions such as zinc ions that are to be eluted from that portion. Has a self-repairing substance (that is, has self-repairing properties). Is effective.

According to the above surface-treated film of the surface-treated steel sheet of the present invention, the organic resin matrix layer on the upper layer side imparts a high degree of barrier property (the above-mentioned action), and the amorphous compound layer on the lower layer side is provided. The surface of the plating film is inactivated by the above action (the above action), and
The self-repairing property (the above-mentioned action) is preferably imparted by the precipitation compound contained in the film, and a high degree of corrosion resistance is imparted to the surface-treated steel sheet by the combined action of these. The amorphous compound layer is a concentrated layer or film of an amorphous compound produced by the reaction of the surface treatment composition and the surface layer of the plating film, and is a plating film component Z.
It is composed of a compound containing Zn and / or Al derived from n and Al. When the plated steel sheet is a zinc-based plated steel sheet, the compositional characteristics of the amorphous compound are Zn
And P are equimolar, and more specifically, the molar ratio [Zn] / [P] of Zn and P is 0.9 to 1.4. This compound is a diphosphate-based compound (for example, Z
nHPO ₄ .2H ₂ O).

By forming such an amorphous compound layer, excellent white rust resistance can be obtained, as described above, because the amorphous compound layer inactivates the plating layer surface layer. It is considered that this is because even if the corrosion factor penetrates the upper barrier layer (organic resin matrix layer) and reaches the surface of the plating film, the anode reaction related to the generation of white rust is suppressed. The thickness of the amorphous compound layer is preferably 10 nm or more from the viewpoint of corrosion resistance. In order to positively form the amorphous compound layer, it is preferable to perform the heat treatment after applying the surface treatment composition by an induction heating method (induction heating furnace). This is because in the heating by the induction heating method, the reaction between the plating film and the surface treatment composition is promoted because the heating is performed from the steel sheet side, which is a condition advantageous for the formation of the amorphous compound layer.

The surface treatment film usually contains a silane compound derived from the silane coupling agent contained in the surface treatment composition. It should be noted that this silane compound also includes a case where it is contained in a composition as a silane coupling agent. Further, in order to impart a high degree of white rust resistance to the surface-treated film, it is preferable that the surface-treated film contains a specific precipitation compound. This precipitation compound is an amorphous precipitation compound containing P, Zn or / and Al, and O, and when this precipitation compound further contains Si, the white rust resistance improving effect is further enhanced. Zn and Al contained in this precipitation compound are Zn and A which are plating film components.
1, and Si is derived from the silane coupling agent contained in the surface treatment composition.

The above-mentioned precipitation compound is considered to be a reaction product (compound) of the plating metal dissolved from the plating film and mainly the acid component in the surface treatment composition, and an appropriate amount of acid component (compound) in the surface treatment composition ( It can be generated (precipitated) in the film by including phosphoric acid. Further, among the deposits, the depositing compound containing Si is one in which the silane coupling agent component in the surface treatment composition is incorporated into the compound, and such a depositing compound also exists in the surface treatment composition. It is possible to generate (precipitate) in the film by optimizing the addition amount of the silane coupling agent (making the addition amount relatively large).

The reason why the white rust resistance is improved by the inclusion of the above-mentioned precipitation compound in the surface treatment film is not necessarily clear, but the acid component such as phosphate ion eluted from the precipitation compound causes plating during the corrosion process. It is presumed that this is because an insoluble compound is formed by combining with metal ions such as zinc ions eluted from the film to form a stable precipitation protective film and suppress corrosion (execute self-repairability). Further, although it is not always clear why the deposition compound contains Si, more excellent white rust resistance is obtained, but the inclusion of Si increases the solubility of the deposition compound in a corrosive environment. It is conceivable that, by incorporating Si in the amorphous compound layer, the reaction product with metal ions such as zinc ions eluted from the plating film during the corrosion process becomes more stable. When the plated steel sheet is a zinc-based plated steel sheet, the precipitation compound contained in the surface treatment film usually contains Zn and P in equimolar amounts. More specifically, the molar ratio of Zn and P [Zn] /
[P] is 0.9 to 1.4, and this compound is presumed to be a diphosphate compound (for example, ZnHPO ₄ .2H ₂ O).

On the other hand, the molar ratio of Zn and P in the surface treatment film
When a precipitation compound having a [Zn] / [P] of less than 1.0 is deposited, the white rust resistance is more improved than when a precipitation compound containing equimolar amounts of Zn and P is deposited. The precipitated compound having a molar ratio [Zn] / [P] of less than 1.0 is a water-soluble primary phosphate (for example, Zn (H ₂ PO ₄ ) ₂ ·.
It is presumed that the compound is mainly H ₂ O). The reason why particularly excellent white rust resistance can be obtained by precipitating such a compound is not always clear, but this precipitating compound is a metal such as zinc ion which is to be eluted from the defective portion of the amorphous compound layer. It is presumed that this is because it reacts with ions to form a sparingly soluble dibasic phosphate (for example, dibasic zinc phosphate), thereby fulfilling a high function as a self-repairing substance.

The thickness of the surface treatment film described above is 0.02 to 5 μm, preferably 0.05 to 5 μm, as described above.
It is 5 μm, more preferably 0.3 to 3 μm, still more preferably 0.5 to 2 μm. Further, the surface-treated film may contain a non-chromium-based anticorrosive additive, a solid lubricant, etc., as described above. Further, the surface treatment composition for forming the surface treatment film needs to be of a water-solvent type in order to generate the compound layer (amorphous compound layer) and the precipitation compound as described above, and therefore, the organic solvent As the resin, a water-dispersible resin and / or a water-soluble resin is used.

Next, details of the method for measuring the film composition of the above-mentioned surface-treated film will be described. The quantitative value of the local composition of the coating cross section obtained by the transmission electron microscope and the energy dispersive X-ray analyzer, which are widely used at present, is the method of preparing the cross section sample, the measurement condition of the data, the data processing method, the quantitative correction calculation. The reality is that it changes depending on the law. This is because it is virtually impossible to successively prepare a standard sample for elemental analysis suitable for an unknown sample that can be observed with a transmission electron microscope, and therefore quantitative calculation based on theoretical calculation without using a standard sample must be adopted. The reason is that various calculation models have not been obtained, and the method for quantitatively calculating the relative concentration of the heavy element of Na or more to the light element of Na or less has not been established in the world. In addition to such a situation, how to handle the characteristic X-rays from other than the measurement target portion due to the shape of the cross-section sample, the support of the cross-section sample, and the like greatly influences the quantitative result.

Therefore, in the present invention, the following method was used to measure the above film composition. First, in order to prepare a cross-sectional sample for a transmission electron microscope, a focused ion beam processing device (Focused Ion Beam: FIB) FB200 manufactured by Hitachi, Ltd.
A microsampling mechanism attached to OA was used. Prior to the FIB processing, the surface of the sample piece of the surface-treated steel sheet for forming a cross-section sample was coated with a protective film of C for 200 n in order to protect it from damage due to ion beam irradiation.
Flash deposition was performed around m, and a protective film of Au was further sputter coated thereon to a thickness of about 100 nm. The surface of the cross-section sample cut-out portion of the sample material introduced into the FIB processing apparatus is further covered with a C protective film of about 500 nm by using the chemical vapor deposition (CVD) mechanism of the FIB processing apparatus, and then the cross-section sample is cut out. Processed. The cross-section sample taken out by using the micro sampling mechanism was fixed on the linear portion of the meniscus-shaped special mesh made of Mo using the CVD mechanism, and then finished to a film thickness suitable for transmission electron microscope observation. For the composition analysis of the cross-section sample created in this way,
A transmission electron microscope CM20FEG manufactured by Philips equipped with a field emission electron gun and an energy dispersive X-ray analyzer Phoenix manufactured by EDAX equipped with a Super-UTW type detector attached thereto were used. The accelerating voltage during microscopic image observation and elemental analysis was 200 kV.

The compositions of the amorphous compound layer and the precipitated compound were determined by performing background removal, peak separation, and quantitative correction calculation from the spectral data collected from these positions. At that time, if the background processing is automatically performed, the net intensity (net intensity) in the light element region may not be calculated appropriately. Therefore, manually specify the energy position where the peak does not appear, and connect it to the manual background. It was processed (removed) by the ground method. For peak separation, Mo mesh or A used as a support for cross-section samples
Characteristic X-rays such as Mo and Au due to the protective layer of u and Ga due to FIB processing were also considered. Quantitative calculation was performed using the characteristic X-rays of the K series of each element contained in the chemical conversion coating. The correction calculation was performed by thin film approximation, and the Zaluzec model was used as the correction factor (so-called K _AB factor). The amorphous compound layer of the surface-treated film and the molar ratio of Zn and P in the deposited compound are Zn and P thus obtained.
It can be obtained as a ratio of atomic concentrations of.

Next, a method for manufacturing the surface-treated steel sheet of the present invention will be described. In order to form the surface treatment film on the surface of a zinc-based plated steel sheet or an aluminum-based plated steel sheet, a surface treatment composition (treatment solution) having the above-mentioned composition is applied to the plated steel sheet surface so that the dry film thickness falls within the above range. Apply and heat dry without washing with water. It is desirable that the surface treatment composition (treatment liquid) is adjusted to pH 0.5 to 6, preferably 2 to 4. When the pH of the surface treatment composition is less than 0.5, the reactivity of the treatment liquid is too strong, which causes uneven appearance.
On the other hand, when the pH exceeds 6, the reactivity of the treatment liquid becomes low,
The bond between the plated metal and the coating becomes insufficient, and corrosion resistance decreases.

The surface treatment composition may be formed on the surface of the plated steel sheet by any of a coating method, a dipping method and a spraying method. As a coating treatment method, any method such as a roll coater (3 roll system, 2 roll system, etc.), a squeeze coater, a die coater or the like may be used. It is also possible to adjust the coating amount, make the appearance uniform, and make the film thickness uniform by an air knife method or a roll squeezing method after the coating or dipping treatment using a squeeze coater or the like, and the spray treatment.

After coating the surface treatment composition,
Heat drying without washing with water. As the heating / drying means, a dryer, a hot air oven, a high frequency induction heating oven, an infrared oven or the like can be used. Heat drying is 30 at the ultimate plate temperature
To 300 ° C, preferably 50 to 300 ° C, more preferably 60 ° C to 250. If the heating and drying temperature is lower than 30 ° C., a large amount of water remains in the film, resulting in insufficient corrosion resistance. On the other hand, if it exceeds 300 ° C, not only is it uneconomical, but also the coating film has defects and the corrosion resistance decreases. Further, when an organic resin film is formed as a second layer film on the upper layer of the surface treatment film formed as described above, the treatment composition for the second layer film is formed to have the above-mentioned film thickness. Apply on the surface of the treated film and heat dry. The application of the treatment composition and the heat drying may be performed according to the method used for forming the surface treatment film described above.

Therefore, the manufacturing method of the present invention and its preferred embodiments are as follows. [1] On the surface of a zinc-based plated steel sheet or an aluminum-plated steel sheet, (a) a reaction product of an epoxy group-containing resin and an active hydrogen-containing compound, and part or all of the active hydrogen-containing compound is active. A water-dispersible resin and / or a water-soluble resin which is a hydrazine derivative having hydrogen,
(B) silane coupling agent, (c) phosphoric acid and /
Or it contains hexafluorometal acid and has a pH of 0.5-
6. The surface treatment composition prepared in No. 6 is applied and heated and dried at an ultimate plate temperature of 50 ° C. to 300 ° C. without washing with water to form a surface treated film having a film thickness of 0.02 to 5 μm. A method for producing a surface-treated steel sheet having excellent white rust resistance.

[2] In the production method of the above-mentioned [1], the surface treatment composition contains the silane coupling agent in an amount of 1 per 100 parts by weight of the solid content of the water-dispersible resin and / or the water-soluble resin.
To 300 parts by weight, 0.1 to 80 parts by weight of phosphoric acid and / or hexafluorometalic acid with respect to 100 parts by weight of the solid content of the water-dispersible resin and / or the water-soluble resin. A method for producing a surface-treated steel sheet having excellent rust properties. [3] In the production method of the above-mentioned [1] or [2], the surface treatment composition further comprises a water-soluble phosphate as a solid based on 100 parts by weight of the solid content of the water-dispersible resin and / or the water-soluble resin. The method for producing a surface-treated steel sheet having excellent white rust resistance, which comprises 0.1 to 60 parts by weight per minute.

[4] In the production method of the above-mentioned [3], the surface treatment composition is a water-soluble phosphate, and the cation component and P ₂
The molar ratio [cation] / [P ₂ O ₅ ] of the O ₅ component is 0.4.
To 1.0 and the cationic species are Mn, Mg, A
1. A method for producing a surface-treated steel sheet having excellent white rust resistance, which comprises at least one water-soluble phosphate selected from Ni and Ni. [5] In the production method of any of the above-mentioned [1]-[4], the surface treatment composition further comprises a non-chromium-based rust preventive additive, and the solid content of the water-dispersible resin and / or the water-soluble resin is 100% by weight. A method for producing a surface-treated steel sheet having excellent white rust resistance, characterized in that 0.1 to 50 parts by weight of solid content is contained with respect to parts.

[6] In the production method of the above-mentioned [5], the surface treatment composition is used as a non-chromium rust preventive additive,
1) A method for producing a surface-treated steel sheet having excellent white rust resistance, comprising one or more rust preventive additives selected from the group of (e5). (E1) silicon oxide (e2) calcium and / or calcium compound (e3) sparingly soluble phosphoric acid compound (e4) molybdic acid compound (e5) selected from triazoles, thiols, thiadiazoles, thiazoles and thiurams One or more S-containing organic compounds

[7] In the manufacturing method according to any one of the above [1] to [6], the surface treatment composition further comprises a solid lubricant, and the solid content of the water-dispersible resin and / or the water-soluble resin is 100 parts by weight. The method for producing a surface-treated steel sheet having excellent white rust resistance, characterized in that the solid content is 1 to 50 parts by weight. [8] In the production method according to any one of the above [1] to [7], the surface treatment composition contains, as a silane coupling agent, at least one silane coupling agent having an amino group as a reactive functional group. A method for producing a surface-treated steel sheet having excellent white rust resistance, which comprises:

[9] In the manufacturing method according to any one of the above [1] to [8], the surface treatment composition contains one or more elements selected from Ti, Si and Zr as a hexafluorometal acid. A method for producing a surface-treated steel sheet having excellent white rust resistance, which comprises at least one kind of hexafluorometal acid. [10] In the manufacturing method according to any one of the above [5] to [9], the surface treatment composition has a white rust resistance characterized by containing calcium ion-exchanged silica as a non-chromium rust preventive additive. Excellent surface-treated steel sheet manufacturing method.

[11] In the production method of any of the above-mentioned [1] to [10], the surface treatment composition contains a water-dispersible resin as the component (a), and the water-dispersible resin is A polyalkylene glycol-modified epoxy resin (A) obtained by reacting a polyalkylene glycol having an average molecular weight of 400 to 20000, a bisphenol type epoxy resin, an active hydrogen-containing compound and a polyisocyanate compound, and the polyalkylene glycol-modified epoxy resin (A Other than the epoxy group-containing resin (B) and a hydrazine derivative (C) having active hydrogen, which is an aqueous epoxy resin dispersion obtained by reacting the surface treatment with excellent white rust resistance. Steel plate manufacturing method.

[12] In the production method of any of the above-mentioned [1] to [10], the surface treatment composition contains a water-dispersible resin as the component (a), and the water-dispersible resin is A polyalkylene glycol modified epoxy resin (A) obtained by reacting a polyalkylene glycol having an average molecular weight of 400 to 20,000, a bisphenol type epoxy resin, an active hydrogen-containing compound and a polyisocyanate compound, and the polyalkylene glycol modified epoxy resin (A Other than the epoxy group-containing resin (B), a hydrazine derivative (C) having active hydrogen, and an active hydrogen-containing compound (D) other than the hydrazine derivative (C) are reacted to obtain an aqueous epoxy resin dispersion. A method for producing a surface-treated steel sheet having excellent white rust resistance, which is a liquid.

[13] In the production method of the above [11] or [12], the epoxy group-containing resin (B) has a number average molecular weight of 15
A method for producing a surface-treated steel sheet excellent in white rust resistance, which is a bisphenol A type epoxy resin having an epoxy equivalent of 00 to 10000 and an epoxy equivalent of 150 to 5000. [14] In the manufacturing method according to any one of the above [11] to [13],
A method for producing a surface-treated steel sheet having excellent white rust resistance, characterized in that the aqueous epoxy resin dispersion further contains a curing agent having a group that crosslinks with a hydroxyl group. [15] In the manufacturing method according to any one of the above [1] to [14],
A method for producing a surface-treated steel sheet having excellent white rust resistance, which comprises forming a surface-treated film having a film thickness of 0.05 to 5 μm.

[16] The coating thickness of the surface-treated steel sheet obtained by the production method according to any one of the above [1] to [14] is 0.02 μm.
An organic resin coating having a coating thickness of 0.02 μm or more and less than 5 μm is formed on the upper layer of the surface treatment coating having a thickness of 5 μm or less so that the total thickness of the surface treatment coating and the surface treatment coating is 5 μm or less. A method for producing a surface-treated steel sheet having excellent white rust resistance. [17] An organic resin film having a film thickness of 0.05 μm or more and less than 5 μm is formed on the upper surface of the surface-treated film having the film thickness of the surface-treated steel sheet obtained by the production method of [15] above, which is 0.05 μm or more and less than 5 μm. A method for producing a surface-treated steel sheet excellent in white rust resistance, which is characterized in that the total thickness of the surface-treated coating and the coating is 5 μm or less.

The above-mentioned surface treatment film may be formed on one side or both sides of the plated steel sheet, and the combination of the coating forms on the front and back surfaces of the plated steel sheet is, for example, a single layer coating (surface treatment coating) / no coating. Treated, two-layer coating (surface treatment coating + organic resin coating) / untreated, single-layer coating (surface treatment coating)
/ Two-layer coating (surface treatment coating + organic resin coating), two-layer coating (surface treatment coating + organic resin coating) / two-layer coating (surface treatment coating + organic resin coating), etc.

[0125]

Examples [Example 1] As a resin composition for a surface treatment composition, the water-dispersible resin shown in Table 2 was used, and a silane coupling agent (Table 3), phosphoric acid or hexafluorometal acid (Table 4), water-soluble phosphate (Table 5), non-chromium rust preventive additive (Table 6), and solid lubricant (Table 7) are appropriately blended, and a paint disperser (sand grinder) is used for a predetermined time. The mixture was stirred to prepare a surface treatment composition.

The plated steel sheets shown in Table 1, which are plated steel sheets for cold-rolled steel sheets for home electric appliances, building materials, and automobile parts, were used as the original treatment plates. The plate thickness of the steel plate used was a predetermined plate thickness according to the purpose of evaluation. The surface of this plated steel sheet was subjected to an alkali degreasing treatment, washed with water and dried, and then the surface treatment composition was applied with a roll coater and heated and dried at various temperatures. The film thickness of the film was adjusted by the solid content (heating residue) of the surface treatment composition or the coating conditions (roll rolling force, rotation speed, etc.). Tables 8 to 19 show the results of evaluating the film composition and quality performance (film appearance, white rust resistance, conductivity, paint adhesion) of the obtained surface-treated steel sheet. The quality performance was evaluated as follows.

(1) Appearance of coating film Each sample was visually evaluated for uniformity of coating appearance (with or without unevenness). The evaluation criteria are as follows. ◯: Uniform appearance with no unevenness Δ: Appearance with slight unevenness X: Appearance with unevenness (2) White rust resistance For each sample, salt spray test (JIS-Z-23
71) was applied, and the white rust area ratio after 120 hours was evaluated. The evaluation criteria are as follows. ◎: White rust area ratio less than 5% ○: White rust area ratio 5% or more and less than 10% ○-: White rust area ratio 10% or more and less than 25% △: White rust area ratio 25% or more, less than 50% × : White rust area ratio 50% or more

(3) Conductivity The interlayer insulation resistance value was measured according to JIS C 2550.
The evaluation criteria are as follows. ○: 3Ω · cm less than ² / sheets △: 3~5Ω · cm ² / sheet ×: 5Ω · cm ² / sheet exceeded (4) for the paint adhesion each sample paint baking paint melamine (thickness 30 [mu] m) After that, it was dipped in boiling water for 2 hours, immediately cut in a grid pattern (10 × 10 pieces, at 1 mm intervals), attached and peeled with an adhesive tape, and the peeled area ratio of the coating film was measured. The evaluation criteria are as follows. ◎: No peeling ○: Peeling area ratio less than 5% △: Peeling area ratio 5% or more, less than 20% ×: Peeling area ratio 20% or more

[0129]

[Table 1]

[0130]

[Table 2]

[0131]

[Table 3]

[0132]

[Table 4]

[0133]

[Table 5]

[0134]

[Table 6]

[0135]

[Table 7]

Note that * 1 to * 8 described in Tables 8 to 19
Indicates the following contents. * 1: No. described in Table 1. (Plated steel sheet) * 2: No. (Water-dispersible resin) * 3: No. (Silane coupling agent) * 4: No. (Phosphoric acid and / or hexafluorometal acid) * 5: No. (Water-soluble phosphate) * 6: No. (Rust preventive additive) * 7: No. (Solid lubricant) * 8: Parts by weight based on 100 parts by weight of the solid content of the water-dispersible resin and / or the water-soluble resin

[0137]

[Table 8]

[0138]

[Table 9]

[0139]

[Table 10]

[0140]

[Table 11]

[0141]

[Table 12]

[0142]

[Table 13]

[0143]

[Table 14]

[0144]

[Table 15]

[0145]

[Table 16]

[0146]

[Table 17]

[0147]

[Table 18]

[0148]

[Table 19]

Example 2 An aqueous epoxy resin dispersion shown in Table 20 was used as a resin composition for a surface treatment composition, and a silane coupling agent (Table 3), phosphoric acid or hexafluorometal acid (Table 3) was used. 4), water-soluble phosphate (Table 2
1), a chromium-free rust preventive additive (Table 6), and a solid lubricant (Table 7) are appropriately blended, and ammonia water, nitric acid, acetic acid,
Adjust the pH to 0.5 with sulfuric acid, phosphoric acid, hexafluorometal acid, etc.
After adjusting to ~ 6, the mixture was stirred for a predetermined time using a paint disperser (sand grinder) to prepare a surface treatment composition.

The plated steel sheet shown in Table 1, which is a plated steel sheet for home electric appliances, building materials and automobile parts, which is based on the cold rolled steel sheet, was used as a treated original sheet. The plate thickness of the steel plate used was a predetermined plate thickness according to the purpose of evaluation. The surface of this plated steel sheet was subjected to an alkali degreasing treatment, washed with water and dried, and then the surface treatment composition was applied with a roll coater and heated and dried at various temperatures. The film thickness of the film was adjusted by the solid content (heating residue) of the surface treatment composition or the coating conditions (roll rolling force, rotation speed, etc.). Tables 22 to 33 show the results of evaluating the film composition and quality performance (film appearance, white rust resistance, conductivity, paint adhesion) of the obtained surface-treated steel sheet. In addition,
The quality performance was evaluated in the same manner as in [Example 1], but the white rust resistance was evaluated by the white rust area ratio after 168 hours had elapsed.

Production examples of the aqueous epoxy resin dispersion shown in Table 20 are shown below. -Production Production Example 1 of Polyalkylene Glycol-Modified Epoxy Resin To a glass 4-necked flask equipped with a thermometer, a stirrer, and a cooling tube, 1688 g of polyethylene glycol having a number average molecular weight of 4000 and 539 g of methyl ethyl ketone were added, and the temperature was 60 ° C.
After stirring and mixing to make it uniform and transparent, 171 g of tolylene diisocyanate was added and reacted for 2 hours, and then Epicoat 834X90 (epoxy resin, manufactured by Shell Japan,
1121 g of epoxy equivalent 250), 66 g of diethylene glycol ethyl ether and 1.1 g of 1% dibutyltin dilaurate solution were added and the reaction was continued for 2 hours. After that, the temperature was raised to 80 ° C. and the reaction was carried out for 3 hours, and it was confirmed that the isocyanate value was 0.6 or less. After that, the temperature is raised to 90 ° C. and the solid content concentration is reduced to 8 by vacuum distillation.
Methyl ethyl ketone was removed to 1.7%. After removal, propylene glycol monomethyl ether 659
g, deionized water (270 g) was added to dilute, and the solid content was 7
A 6% polyalkylene glycol-modified epoxy resin solution A1 was obtained.

Production of Aqueous Epoxy Resin Dispersion Production Example 2 2029 g of EP1004 (epoxy resin, manufactured by Yuka Shell Epoxy Co., Ltd., epoxy equivalent 1000) and 697 g of propylene glycol monobutyl ether were charged in a four-necked flask and heated to 110 ° C. Then, the epoxy resin was completely dissolved in 1 hour. To this, 118 polyalkylene glycol-modified epoxy resin solution A1 obtained in Production Example 1 was added.
0 g and 311.7 g of 3-amino-1,2,4-triazole (molecular weight 84) were added and reacted at 100 ° C. for 5 hours, and then propylene glycol monobutyl ether 71
A resin solution D1 was obtained by adding 9.6 g. Resin solution D
257.6 g of MF-1 was mixed with 50 g of MF-K60X (isocyanate curing agent, manufactured by Asahi Kasei Kogyo Co., Ltd.) and 0.3 g of Scat24 (curing catalyst), and after stirring well, water 69
2.1 g of the solution was added little by little and mixed and stirred to obtain an aqueous epoxy resin dispersion E1.

Production Example 3 (Aqueous epoxy resin dispersion containing no hydrazine derivative) 20100 g of EP1004 (epoxy resin, manufactured by Yuka Shell Epoxy Co., Ltd., epoxy equivalent 1000) and 697 g of propylene glycol monobutyl ether were charged in a four-necked flask, and 110 The temperature was raised to 0 ° C. and the epoxy resin was completely dissolved in 1 hour. To this, 118 polyalkylene glycol-modified epoxy resin solution A1 obtained in Production Example 1 was added.
0 g and propylene glycol monobutyl ether 5
27.0 g was added to obtain a resin solution D2. 257.6 g of the above resin solution D2 was mixed with 50 g of MF-K60X (isocyanate curing agent, manufactured by Asahi Kasei Kogyo Co., Ltd.) and 0.3 g of Scat24 (curing catalyst) and stirred well, and then water 692.
1 g little by little was added dropwise and mixed and stirred to obtain an aqueous epoxy resin dispersion E2.

[0154]

[Table 20]

[0155]

[Table 21]

Note that * 1 to * described in Tables 22 to 33
8 indicates the following contents. * 1: No. described in Table 1. (Plated steel sheet) * 2: No. (Water-dispersible resin) * 3: No. (Silane coupling agent) * 4: No. (Phosphoric acid and / or hexafluorometallic acid) * 5: No. (Water-soluble phosphate) * 6: No. (Rust preventive additive) * 7: No. (Solid lubricant) * 8: Parts by weight based on 100 parts by weight of the solid content of the water-dispersible resin

[0157]

[Table 22]

[0158]

[Table 23]

[0159]

[Table 24]

[0160]

[Table 25]

[0161]

[Table 26]

[0162]

[Table 27]

[0163]

[Table 28]

[0164]

[Table 29]

[0165]

[Table 30]

[0166]

[Table 31]

[0167]

[Table 32]

[0168]

[Table 33]

[Example 3] In Examples 1 to 3 of the present invention, Nos. 1 of the aqueous epoxy resin dispersion, N of Table 3
o. The surface treatment composition containing the silane coupling agent of No. 1 and phosphoric acid was used. Further, in Comparative Example, No.
The surface treatment composition consisting of the aqueous epoxy resin dispersion liquid 1 was used. These surface treatment compositions were subjected to alkaline degreasing treatment on the surface, washed with water, and dried, and were subjected to No. 1 in Table 1. The coated steel sheet of No. 1 was coated with a roll coater and dried by heating at 140 ° C. to form a surface-treated coating having a thickness of 0.5 μm.

A salt spray test (JIS Z 2371) was conducted on the obtained surface-treated steel sheet, and the white rust resistance was evaluated according to the following evaluation criteria based on the time until the white rust area occurrence rate became 5%. evaluated. The results are shown in Table 34 together with the constitution of the surface treatment composition. ◎: 168 hours or more ○: 96 hours or more, less than 168 hours ○-: 72 hours or more, less than 96 hours Δ: 24 hours or more, less than 72 hours ×: less than 24 hours

The results of investigating the film structures of the surface-treated steel sheets of Examples 1 to 3 of the present invention and Comparative Example are shown below. The samples were prepared and measured under the conditions described above. Comparative Example FIG. 1 shows an electron micrograph (bright field image) of a cross section of the surface-treated film of the comparative example. Since the surface-treated film of the comparative example is composed of only the organic resin barrier layer, the white rust resistance is insufficient as shown in Table 34.

Inventive Example 1 FIG. 2 is an electron micrograph (bright field image) of a cross section of the surface-treated coating of Inventive Example 1, and FIG. 3 is a composition analysis result of the coating cross section (line analysis: vertical axis represents atomic concentration). The description is omitted because most of the C concentration is overscaled. The same applies to FIGS. 5 and 7 described later). According to these, a surface treatment film is formed in which the lower layer portion is a compound layer (amorphous compound layer) containing P, Zn and O and equimolar amounts of Zn and P, and the upper layer portion is an organic resin matrix layer. It is understood that there is. According to the electron diffraction pattern,
The compound layer is amorphous. In FIG. 3 (the same applies to FIGS. 5 and 7 described later), Z in the compound layer
The reason why n and P deviate from the equimolar amount to the Zn rich side on the galvanized film side is that the electron beam probe diameter has a finite size (the galvanized layer itself and the compound layer are at the compound layer / plated layer interface). At the same time, the effect of being included in the probe diameter). As shown in Table 34, the invention example 1 has a corrosion resistance that is three times or more that of the comparative example in white rust generation time.

Inventive Example 2 FIG. 4 is an electron micrograph (bright-field image of a cross-section of the surface-treated coating of Inventive Example 2. The arrow in FIG. 4 indicates a precipitated compound,
The diagonal broken line corresponds to the line analysis position in FIG.
The results of composition analysis of the cross section of the coating (the downward arrows in the graph correspond to the positions of the precipitated compounds) are shown in each. According to these, a compound layer (amorphous compound layer) containing P, Zn, and O and equimolar amounts of Zn and P was formed in the lower layer portion of the surface-treated film, as in Example 1 of the present invention. There is. Furthermore, in this Inventive Example 2, P and Zn were contained in the surface treatment film.
And a compound containing O is precipitated. According to the electron diffraction pattern, the compound layer and the deposited compound are amorphous. As shown in Table 34, the invention example 2 has a corrosion resistance that is four times or more that of the comparative example in terms of white rust generation time.

Inventive Example 3 FIG. 6 is an electron micrograph (bright-field image of the cross section of the surface-treated coating of Inventive Example 3. The arrow in FIG. 6 indicates a precipitated compound,
The diagonal broken line corresponds to the line analysis position in FIG. 7.
The results of composition analysis of the cross section of the coating (the downward arrows in the graph correspond to the positions of the precipitated compounds) are shown in each. According to these, similarly to the invention examples 1 and 2, a compound layer (amorphous compound layer) containing P, Zn, and O and equimolar amounts of Zn and P is formed in the lower layer portion of the surface treatment film. Has been done. Furthermore, in this Inventive Example 3, Z was added to the surface treatment film.
A compound containing n, P, Si and O is deposited. In addition, these precipitation compounds have a molar ratio [Zn] of Zn and P.
/ [P] is less than 1.0. According to the electron diffraction pattern, the compound layer and the deposited compound are amorphous.
As shown in Table 34, the invention example 3 has a corrosion resistance that is 7 times or more that of the comparative example in white rust generation time.

[0175]

[Table 34]

In addition, * 1 to * 4 described in Table 34 indicate the following contents. * 1: No. described in Table 20. (Water-dispersible resin) * 2: No. (Silane coupling agent) * 3: No. (Phosphoric acid and / or hexafluorometalic acid) * 4: parts by weight based on 100 parts by weight of the solid content of the water-dispersible resin

[0177]

As described above, the surface-treated steel sheet of the present invention has very excellent corrosion resistance even though it does not contain chromium, and also has excellent characteristics in terms of film appearance and paint adhesion. have.

[Brief description of drawings]

FIG. 1 is an electron microscopic enlarged photograph of the cross-sectional structure of the surface-treated coating of Comparative Example.

FIG. 2 is an electron microscopic enlarged photograph of the cross-sectional structure of the surface-treated coating of Inventive Example 1.

FIG. 3 is a graph showing the composition analysis result of the cross section of the surface-treated film of Inventive Example 1.

FIG. 4 is an electron microscopic enlarged photograph of the cross-sectional structure of the surface-treated coating of Inventive Example 2.

FIG. 5 is a graph showing the composition analysis results of the cross section of the surface-treated film of Inventive Example 2.

FIG. 6 is an electron microscopic enlarged photograph of the cross-sectional structure of the surface-treated coating of Inventive Example 3.

FIG. 7 is a graph showing the composition analysis results of the cross section of the surface-treated film of Inventive Example 3.

Continued front page    (72) Inventor Akira Matsuzaki             1-2-1, Marunouchi, Chiyoda-ku, Tokyo             Main Steel Pipe Co., Ltd. (72) Inventor Naoto Yoshimi             1-2-1, Marunouchi, Chiyoda-ku, Tokyo             Main Steel Pipe Co., Ltd. (72) Inventor Takahiro Kubota             1-2-1, Marunouchi, Chiyoda-ku, Tokyo             Main Steel Pipe Co., Ltd. (72) Inventor Masaaki Yamashita             1-2-1, Marunouchi, Chiyoda-ku, Tokyo             Main Steel Pipe Co., Ltd. (72) Inventor Hisato Noro             1-2-1, Marunouchi, Chiyoda-ku, Tokyo             Main Steel Pipe Co., Ltd. (72) Inventor Jiro Nakamichi             1-2-1, Marunouchi, Chiyoda-ku, Tokyo             Main Steel Pipe Co., Ltd. (72) Inventor Kaoru Sato             1-2-1, Marunouchi, Chiyoda-ku, Tokyo             Main Steel Pipe Co., Ltd. (72) Inventor Hiroyasu Matsuki             Seki, 4-17-1, Higashi-Hachiman, Hiratsuka City, Kanagawa Prefecture             West Paint Co., Ltd. (72) Inventor Reijiro Nishida             Seki, 4-17-1, Higashi-Hachiman, Hiratsuka City, Kanagawa Prefecture             West Paint Co., Ltd. (72) Inventor Masahiro Murata             Seki, 4-17-1, Higashi-Hachiman, Hiratsuka City, Kanagawa Prefecture             West Paint Co., Ltd. F term (reference) 4K026 AA02 AA07 AA09 AA11 AA12                       AA13 BA03 BB01 BB08 CA13                       CA23 CA26 CA27 CA29 CA37                       CA38 DA02 DA03 DA06 DA11                       EA11 EB11                 4K044 AA02 AA06 AB02 BA02 BA04                       BA06 BA10 BA14 BA17 BA19                       BA20 BA21 BB04 BB05 BC02                       BC03 BC09 CA11 CA16 CA17                       CA53 CA62

Claims (28)

[Claims] 1. A reaction product of (a) an epoxy group-containing resin and an active hydrogen-containing compound on the surface of a zinc-based plated steel sheet or an aluminum-based plated steel sheet, and part or all of the active hydrogen-containing compound. A water-dispersible resin and / or a water-soluble resin, in which is a hydrazine derivative having active hydrogen, (b) a silane coupling agent, and (c) a phosphoric acid and / or a hexafluorometal acid. A surface-treated steel sheet having excellent white rust resistance, which has a surface-treated film having a film thickness of 0.02 to 5 μm formed by coating and drying. 2. The surface treatment composition comprises a silane coupling agent, a water-dispersible resin and / or a water-soluble resin having a solid content of 1.
1 to 300 parts by weight with respect to 00 parts by weight, phosphoric acid and /
Alternatively, hexafluoro metal acid is added in an amount of 0.1 to 100 parts by weight of the solid content of the water-dispersible resin and / or the water-soluble resin.
80 weight part is contained, The surface-treated steel sheet excellent in white rust resistance of Claim 1 characterized by the above-mentioned. 3. The surface treatment composition further contains a water-soluble phosphate in an amount of 0.1 to 60 parts by weight based on 100 parts by weight of the solid content of the water-dispersible resin and / or the water-soluble resin. The surface-treated steel sheet having excellent white rust resistance according to claim 1 or 2. 4. The surface treatment composition is a water-soluble phosphate salt.
And cation component and P_TwoO ₅Molar ratio of components [cation]
/ [P_TwoO₅] Is 0.4 to 1.0, and Catio
1 or more selected from Mn, Mg, Al and Ni
A contract characterized by containing the above water-soluble phosphate
A surface-treated steel sheet having excellent white rust resistance according to claim 3. 5. The surface treatment composition further comprises a chromium-free rust preventive additive in an amount of 0.1 to 50 parts by weight based on 100 parts by weight of the water-dispersible resin and / or the water-soluble resin. It contains, Claim 1, 2, 3 or 4 characterized by the above-mentioned.
Surface-treated steel sheet with excellent white rust resistance as described in. 6. The surface treatment composition is selected from the following groups (e1) to (e5) as a chromium-free rust preventive additive:
The surface-treated steel sheet having excellent white rust resistance according to claim 5, which contains one or more rust preventive additives. (E1) silicon oxide (e2) calcium and / or calcium compound (e3) sparingly soluble phosphoric acid compound (e4) molybdic acid compound (e5) selected from triazoles, thiols, thiadiazoles, thiazoles and thiurams One or more S-containing organic compounds 7. The surface treatment composition further comprises a solid lubricant, solid content 1 of the water-dispersible resin and / or the water-soluble resin.
The surface-treated steel sheet excellent in white rust resistance according to claim 1, 2, 3, 4, 5 or 6, wherein the solid content is 1 to 50 parts by weight with respect to 00 parts by weight. 8. The surface treatment composition contains, as the silane coupling agent, at least one silane coupling agent having an amino group as a reactive functional group. The surface-treated steel sheet having excellent white rust resistance according to 4, 5, 6 or 7. 9. The surface treatment composition contains at least one hexafluorometal acid containing one or more elements selected from Ti, Si and Zr as the hexafluorometal acid. Items 1, 2, 3, 4, 5,
The surface-treated steel sheet excellent in white rust resistance according to 6, 7, or 8. 10. The white rust resistance according to claim 5, 6, 7, 8 or 9, wherein the surface treatment composition contains calcium ion exchange silica as a non-chromium rust preventive additive. Excellent surface-treated steel sheet. 11. The surface treatment composition contains a water-dispersible resin as a component (a), and the water-dispersible resin is a polyalkylene glycol having a number average molecular weight of 400 to 20,000,
A polyalkylene glycol-modified epoxy resin (A) obtained by reacting a bisphenol type epoxy resin, an active hydrogen-containing compound and a polyisocyanate compound, and an epoxy group-containing resin (B) other than the polyalkylene glycol-modified epoxy resin (A) An aqueous epoxy resin dispersion obtained by reacting a hydrazine derivative (C) having active hydrogen with each other.
The surface-treated steel sheet excellent in white rust resistance according to 4, 5, 6, 7, 8, 9 or 10. 12. The surface treatment composition contains a water-dispersible resin as a component (a), and the water-dispersible resin is a polyalkylene glycol having a number average molecular weight of 400 to 20,000,
A polyalkylene glycol-modified epoxy resin (A) obtained by reacting a bisphenol type epoxy resin, an active hydrogen-containing compound and a polyisocyanate compound, and an epoxy group-containing resin (B) other than the polyalkylene glycol-modified epoxy resin (A) An aqueous epoxy resin dispersion obtained by reacting a hydrazine derivative (C) having active hydrogen with an active hydrogen-containing compound (D) other than the hydrazine derivative (C). 1,
The surface-treated steel sheet excellent in white rust resistance according to 2, 3, 4, 5, 6, 7, 8, 9, or 10. 13. The epoxy group-containing resin (B) has a number average molecular weight of 1500 to 10,000 and an epoxy equivalent of 150 to 5.
000 of bisphenol A type epoxy resin, The surface-treated steel sheet excellent in white rust resistance according to claim 11 or 12. 14. The surface-treated steel sheet excellent in white rust resistance according to claim 11, 12 or 13, wherein the aqueous epoxy resin dispersion liquid further contains a curing agent having a group capable of crosslinking with a hydroxyl group. . 15. P, Zn or / and Al, on the surface of a zinc-based plated steel sheet or an aluminum-based plated steel sheet,
A surface-treated film having a film thickness of 0.02 to 5 μm, which is composed of an amorphous compound layer containing and O and an organic resin matrix layer having an epoxy group-containing resin modified with a hydrazine derivative as a matrix thereabove. A surface-treated steel sheet having excellent white rust resistance, which is characterized by having: 16. The surface-treated steel sheet excellent in white rust resistance according to claim 15, wherein the surface-treated film further contains a silane compound. 17. The surface-treated steel sheet excellent in white rust resistance according to claim 15 or 16, wherein the surface-treated coating contains a precipitation compound containing P, Zn or / and Al, and O. . 18. The surface-treated coating contains a precipitation compound containing P, Zn or / and Al, Si and O, and is excellent in white rust resistance according to claim 15, 16 or 17. Surface treated steel sheet. 19. A surface-treated steel sheet having a surface-treated coating on the surface of a zinc-based plated steel sheet, wherein the molar ratio [Zn] / [P] of Zn and P in the amorphous compound layer is 0.9 to 1. .4.
Surface-treated steel sheet with excellent white rust resistance as described in. 20. A surface-treated steel sheet having a surface-treated coating on the surface of a zinc-based plated steel sheet, wherein the molar ratio [Zn] / [P] of Zn and P in the precipitation compound contained in the surface-treated coating is 0. 18. The method according to claim 17, wherein the value is 9 to 1.4.
The surface-treated steel sheet having excellent white rust resistance according to 8 or 19. 21. A surface-treated steel sheet having a surface-treated coating on the surface of a zinc-based plated steel sheet, wherein the molar ratio [Zn] / [P] of Zn and P in the precipitation compound contained in the surface-treated coating is 1. It is less than 0, The surface-treated steel sheet excellent in white rust resistance according to claim 17, 18 or 19. 22. The surface-treated film further contains a non-chromium rust preventive additive in an amount of 0.1 to 50 parts by weight based on 100 parts by weight of the solid content of the organic resin. The surface-treated steel sheet excellent in white rust resistance according to 15, 16, 17, 18, 19, 20, or 21. 23. The surface-treated film is selected from the following groups (e1) to (e5) as a chromium-free rust preventive additive:
The surface-treated steel sheet having excellent white rust resistance according to claim 22, characterized by containing one or more rust preventive additives. (E1) silicon oxide (e2) calcium and / or calcium compound (e3) sparingly soluble phosphoric acid compound (e4) molybdic acid compound (e5) selected from triazoles, thiols, thiadiazoles, thiazoles and thiurams One or more S-containing organic compounds 24. The surface-treated steel sheet excellent in white rust resistance according to claim 23, wherein the surface-treated coating contains calcium ion-exchanged silica as a non-chromium rust preventive additive. 25. The surface-treated film further comprises a solid lubricant in a solid content of 1 part based on 100 parts by weight of the solid content of the organic resin.
16. 50 parts by weight are contained.
The surface-treated steel sheet excellent in white rust resistance according to 6, 17, 18, 19, 20, 21, 22, 23, or 24. 26. Claims 1, 2, 3, 4, 5, 6, 7,
8, 9, 10, 11, 12, 13, 14, 15, 16,
The surface-treated steel sheet according to 17, 18, 19, 20, 21, 22, 23, 24, or 25 has a coating thickness of 0.02 μm or more and less than 5 μm, and further has a coating thickness of 0.02 μm or more. A surface-treated steel sheet having excellent white rust resistance, which has an organic resin film of less than 5 μm and has a total film thickness of 5 μm or less of the organic resin film and the surface-treated film. 27. Claims 1, 2, 3, 4, 5, 6, 7,
8, 9, 10, 11, 12, 13, 14, 15, 16,
A method for manufacturing a surface-treated steel sheet according to 17, 18, 19, 20, 21, 22, 23, 24, or 25, comprising: (a) an epoxy group-containing resin on the surface of a zinc-based plated steel sheet or an aluminum-based plated steel sheet. A water-dispersible resin and / or a water-soluble resin, which is a reaction product of an active hydrogen-containing compound with a part or all of the active hydrogen-containing compound being a hydrazine derivative having active hydrogen, and (b) silane A surface treatment composition containing a coupling agent and (c) phosphoric acid and / or hexafluorometal acid and having a pH adjusted to 0.5 to 6 is applied, and the surface treatment composition is heated to 50 ° C to 300 ° C without washing with water. A method for producing a surface-treated steel sheet having excellent white rust resistance, which comprises heat-drying at an ultimate plate temperature to form a surface-treated film having a film thickness of 0.02 to 5 μm. 28. The surface-treated steel sheet obtained by the manufacturing method according to claim 27 has a coating thickness of 0.02 μm or more and 5 μm or more.
The thickness of the surface treatment film is less than 0.02μ
A method for producing a surface-treated steel sheet having excellent white rust resistance, comprising forming an organic resin film having a thickness of m or more and less than 5 μm so that a total film thickness including the surface-treatment film thickness is 5 μm or less.