JP5577781B2 - Surface-treated steel sheet - Google Patents

Description

  The present invention relates to an environment-adaptive surface-treated steel sheet that does not contain chromium in a film suitable for applications such as automobiles, home appliances, and building materials, and in particular, prevents electromagnetic wave leakage (EMI) such as electrical / electronic equipment. The present invention relates to a surface-treated steel sheet that is suitable for a required application and has excellent electromagnetic shielding properties and corrosion resistance.

For steel plates for automobiles, steel plates for household appliances, and steel plates for building materials, hexavalent chromium has been used for the purpose of improving corrosion resistance (white rust resistance, red rust resistance) on the surface of zinc-plated steel sheets or aluminum-based plated steel sheets. Steel plates that have been subjected to chromate treatment with a treatment liquid containing as a main component have been widely used. However, since chromate treatment uses hexavalent chromium, which is a pollution-controlling substance, a surface-treated steel sheet with a treatment film that does not use hexavalent chromium at all has been recently proposed in place of the conventionally used chromate treatment. ing. Among these, several techniques using an organic compound or an organic resin have been proposed, and examples include the following.
(1) Technology for forming an organic composite coating comprising a phosphoric acid and / or phosphoric acid compound film containing an oxide in the lower layer and a resin film on the upper layer (for example, Patent Documents 1 and 2).
(2) Technology using a mixed composition in which an organic phosphoric acid compound is blended with a specific titanium-containing aqueous liquid (for example, Patent Document 3)

JP 2002-53980 A JP 2002-53979 A Japanese Patent Laid-Open No. 2006-9121

Since electromagnetic waves generated by electric / electronic devices have various effects on the surrounding environment, an electromagnetic wave shield for preventing electromagnetic leakage (EMI) to the outside is necessary. In recent years, electromagnetic shielding properties have been required for surface-treated steel sheets used for chassis and bottom plates of OA / AV devices. In order to improve the electromagnetic shielding performance, it is necessary to improve the shielding effect of the joints and joints of the chassis and bottom plate. From this viewpoint, the conductivity of the applied steel sheet surface is better than ever. It has come to be required to.
In particular, a member called a gasket is used for the joint portion and joint portion of the steel plate to ensure electromagnetic shielding properties. However, the contact portion between the steel plate surface and the gasket is usually low in contact pressure, so it can be used at low loads. It is necessary to increase conductivity.

On the other hand, the conductivity of the surface-treated steel sheet surface depends on the film thickness of the insulating film coated on the surface. Therefore, the conductivity can be improved by reducing the film thickness of the insulating film. For example, Patent Documents 1 and 2 show that when the adhesion amount of the organic film is 0.5 g / m ² or less, the conductivity is lowered, that is, the electromagnetic wave shielding property is improved. However, as described in Patent Documents 1 and 2, since the corrosion resistance is reduced when the film thickness is reduced, it is difficult to obtain a surface-treated steel sheet having excellent conductivity and corrosion resistance.

Moreover, in patent document 3, a titanium oxide type | system | group of a titanium oxide type | system | group is mix | blended by mix | blending an organic phosphate compound and water-soluble or water-dispersible organic resin with the titanium containing aqueous liquid obtained by mixing a specific titanium compound with hydrogen peroxide water. Precipitation of a dense film component is deposited, and a vanadium acid compound, zirconium fluoride compound, and zirconium carbonate compound are further added to form a composite salt of vanadium and zirconium metal ions, and 0.2 g / m Good corrosion resistance is exhibited even with an adhesion amount of about ² . However, in this technique, zirconium fluoride, which is an essential component for developing corrosion resistance, forms a passive film while dissolving the galvanized crystal, and this passive film covers the conductive part of the plating surface. The electroconductivity under severe conditions where electromagnetic shielding properties are required is insufficient.

  Accordingly, an object of the present invention is to solve such problems of the prior art, and to provide a surface-treated steel sheet that does not contain chromium in the film and has both excellent conductivity and corrosion resistance.

  As a result of intensive studies by the present inventors to solve the above-mentioned problems, a specific titanium compound is obtained as a first layer film on the surface of a zinc-based plated steel sheet or an aluminum-based plated steel sheet by mixing with a hydrogen peroxide solution. The organic phosphoric acid compound, vanadic acid compound, zirconium carbonate compound and silane coupling agent are added in a specific ratio to the titanium-containing aqueous liquid, and water-soluble or water-dispersible organic resin is specified as necessary. A surface-treated steel sheet that combines excellent electrical conductivity and corrosion resistance by forming a film with a surface treatment liquid added at a ratio of 2 and forming a film with a surface treatment liquid containing an organic resin as a second layer film on the upper layer. It was found that can be obtained.

The present invention has been made on the basis of such findings and has the following gist.
[1] At least one selected from a hydrolyzable titanium compound, a hydrolyzable titanium compound low condensate, titanium hydroxide, and a titanium hydroxide low condensate on the surface of a zinc-based plated steel sheet or an aluminum-based plated steel sheet 1 to 400 parts by mass of an organic phosphate compound (B) and a vanadic acid compound (100 parts by mass) with respect to 100 parts by mass of a solid content of a titanium-containing aqueous liquid (A) obtained by mixing a seed titanium compound with hydrogen peroxide. 1) to 500 parts by mass of C), more than 400 parts by mass and 1000 parts by mass or less of the zirconium carbonate compound (D), and 5% of the silane coupling agent (E) in the total solid content of the surface treatment liquid. It has a first layer film formed by applying and drying a surface treatment liquid (α) containing ˜50 mass% ( excluding a surface treatment liquid containing a zirconium fluoride compound) , and in the upper layer, The first layer coating and the second layer coating have a second layer coating formed by applying a surface treatment liquid (β) containing an organic resin (G) to the surface of the first layer coating and drying it. A surface-treated steel sheet having a total film thickness of 0.1 to 2.0 μm per side.
[2] In the surface-treated steel sheet according to [1], the surface treatment liquid (α) further contains a water-soluble organic resin and / or a water-dispersible organic resin (F) in a solid content 100 of the titanium-containing aqueous liquid (A). A surface-treated steel sheet containing 10 to 2000 parts by mass with respect to parts by mass.

[3] In the surface-treated steel sheet according to [1] or [2], the organophosphate compound (B) contained in the surface treatment liquid (α) is 1-hydroxyethane-1,1-diphosphonic acid. A surface-treated steel sheet.
[4] The surface-treated steel sheet according to any one of [1] to [3], wherein the vanadate compound (C) contained in the surface treatment liquid (α) is ammonium metavanadate. .
[5] The surface-treated steel sheet according to any one of [1] to [4], wherein the zirconium carbonate compound (D) contained in the surface treatment liquid (α) is ammonium zirconium carbonate. .
[6] The surface-treated steel sheet according to any one of [1] to [5], wherein the silane coupling agent (E) contained in the surface treatment liquid (α) has a glycidyl group.
[7] In the surface-treated steel sheet according to any one of [2] to [6], the water-soluble organic resin and / or water-dispersible organic resin (F) contained in the surface treatment liquid (α) is a water-soluble urethane resin. Or / and a surface-treated steel sheet, which is a water-dispersible urethane resin.

[8] In the surface-treated steel sheet according to any one of [1] to [7], at least a part of the organic resin (G) contained in the surface treatment liquid (β) has an OH group and / or a COOH group. A surface-treated steel sheet which is a resin (H).
[9] In the surface-treated steel sheet according to any one of [1] to [7], at least a part of the organic resin (G) contained in the surface treatment liquid (β) is a hydrazine-modified organic resin (K). A surface-treated steel sheet characterized by
[10] The surface-treated steel sheet according to any one of [1] to [9], wherein the surface treatment liquid (β) further contains a rust preventive additive (L).
[11] In the surface-treated steel sheet according to [10], the rust additive (L) is the following (a) and / or (b), and the content of the rust additive (L) is a solid content ratio. The surface-treated steel sheet is 1 to 100 parts by mass with respect to 100 parts by mass of the organic resin in the surface treatment liquid (β).
(A) Ca ion exchange silica (b) Silicon oxide [12] In the surface-treated steel sheet according to any one of [1] to [11], the surface treatment liquid (β) further contains a lubricant (M). A surface-treated steel sheet characterized by that.

  The surface-treated steel sheet of the present invention is an organic phosphoric acid in a titanium-containing aqueous liquid obtained by mixing a specific titanium compound with a hydrogen peroxide solution as a first layer film on the surface of a zinc-based plated steel sheet or an aluminum-based plated steel sheet. Compound, vanadic acid compound, zirconium carbonate compound, and silane coupling agent are added in a specific ratio, and if necessary, corrosion resistance and surface treatment liquid to which water-soluble or water-dispersible organic resin is added in a specific ratio. By forming a film with excellent electrical conductivity and forming a film with a surface treatment liquid containing an organic resin as a second layer film on the upper layer, suppressing excessive elution of the first layer film component, it is chromate-free. Excellent corrosion resistance comparable to chromate film is obtained, and excellent conductivity is obtained even under severe conditions where electromagnetic wave shielding is required. .

The details of the present invention and the reasons for limitation will be described below.
[Base plated steel sheet]
Examples of the galvanized steel sheet used as the base of the surface-treated steel sheet of the present invention include a galvanized steel sheet, a Zn—Ni alloy plated steel sheet, a Zn—Fe alloy plated steel sheet (electroplated steel sheet, galvannealed steel sheet), Zn -Cr alloy plated steel sheet, Zn-Mn alloy plated steel sheet, Zn-Co 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, Zn-5 mass% Al alloy-plated steel sheet, Zn-55 mass% Al alloy-plated steel sheet), Zn-Mg alloy-plated steel sheet, Zn-Al-Mg alloy-plated steel sheet (for example, Zn-6 mass%) Al-3 mass% Mg alloy-plated steel sheet, Zn-11 mass% Al-3 mass% Mg alloy-plated steel sheet), and plating films of these plated steel sheets Metal oxides, dispersed zinc composite-plated steel sheet such as a polymer (e.g., Zn-SiO ₂ dispersion plating steel plate) or the like can be used to.

Moreover, the multilayer plating steel plate which plated two or more layers of the same kind or different kind among the above plating can also be used.
Moreover, as an aluminum system plated steel plate used as the base of the surface treatment steel plate of this invention, an aluminum plating steel plate, an Al-Si alloy plating steel plate, etc. can be used.
Moreover, as a plated steel plate, the steel plate surface may be plated in advance with thinning such as Ni, and the above-described various plating may be performed thereon.
As a plating method, any feasible method such as an electrolytic method (electrolysis in an aqueous solution or electrolysis in a non-aqueous solvent), a melting method, a gas phase method, or the like may be adopted.
Furthermore, in order to prevent blackening of the plating, about 1 to 2000 mass ppm of one or more trace elements of Ni, Co, and Fe are deposited in the plating film, or Ni, Co, and Fe are deposited on the surface of the plating film. You may make it surface-treat with the alkaline aqueous solution or acidic aqueous solution containing 1 or more types, and to precipitate these elements.

The surface-treated steel sheet of the present invention has a first layer film formed by the surface treatment liquid (α) on the surface of the zinc-based plated steel sheet or the aluminum-based plated steel sheet as described above, and the surface treatment liquid is formed thereon. It has a second layer film formed by (β).
[First layer coating]
Hereinafter, the first layer film formed on the surface of the zinc-based plated steel sheet or the aluminum-based plated steel sheet and the surface treatment liquid (α) for forming the film will be described.
In the surface-treated steel sheet of the present invention, the first layer film (surface-treated film) formed on the surface of the zinc-based plated steel sheet or the aluminum-based plated steel sheet is composed of a specific titanium-containing aqueous liquid (A) and an organic phosphate compound ( B), a vanadic acid compound (C), a zirconium carbonate compound (D), and a silane coupling agent (E) are contained in a predetermined ratio, and if necessary, a water-soluble organic resin and / or water dispersibility. It is formed by applying and drying a surface treatment liquid (α) containing an organic resin (F). This surface treatment film does not contain hexavalent chromium (however, excluding chromium as an inevitable impurity).

  Excellent corrosion resistance and conductivity can be obtained by the surface treatment film as described above. The titanium-containing aqueous liquid (A) obtained by mixing a specific titanium compound with a hydrogen peroxide solution is added to an organic phosphate compound (B). ), And if necessary, a water-soluble organic resin and / or water-dispersible organic resin (F) can be added to form a tough film with excellent adhesion to the plated steel sheet. Furthermore, by blending vanadic acid compound (C), zirconium carbonate compound (D), and silane coupling agent (F) at specific ratios, the rust-preventing power is greatly improved even in a thin film, and it is further conductive at low load. This is thought to be due to the improvement in performance.

・ Titanium-containing aqueous liquid (A)
The titanium-containing aqueous liquid (A) contains at least one titanium compound selected from hydrolyzable titanium compounds, hydrolyzable titanium compound low condensates, titanium hydroxide and titanium hydroxide low condensates. It is an aqueous liquid containing titanium obtained by mixing with hydrogen oxide water.
The hydrolyzable titanium compound is a titanium compound having a hydrolyzable group directly bonded to titanium, and generates titanium hydroxide by reacting with water such as water or water vapor. The hydrolyzable titanium compound may be one in which all of the groups bonded to titanium are hydrolyzable groups, or a part of the groups bonded to titanium may be hydrolyzable groups.
The hydrolyzable group is not particularly limited as long as it generates titanium hydroxide by reacting with moisture as described above. For example, a lower alkoxyl group or a group that forms a salt with titanium (for example, Halogen atoms such as chlorine, hydrogen atoms, sulfate ions, etc.).

The hydrolyzable titanium compound containing a lower alkoxyl group as the hydrolyzable group is particularly represented by the general formula Ti (OR) ₄ (wherein R represents the same or different alkyl groups having 1 to 5 carbon atoms). Tetraalkoxy titanium is preferred. Examples of the alkyl group having 1 to 5 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a sec-butyl group, and a tert-butyl group. Can be mentioned.
Typical examples of the hydrolyzable titanium compound having a group capable of forming a salt with titanium as a hydrolyzable group include titanium chloride and titanium sulfate.

Moreover, the low condensate of a hydrolysable titanium compound is a low condensate of the above-mentioned hydrolysable titanium compounds. The low condensate may be one in which all of the groups bonded to titanium are hydrolyzable groups, or a part of the groups bonded to titanium may be hydrolyzable.
For hydrolyzable titanium compounds whose hydrolyzable group forms a salt with titanium (for example, titanium chloride, titanium sulfate, etc.), an aqueous solution of the hydrolyzable titanium compound and an alkaline solution such as ammonia or caustic soda are used. Orthotitanic acid (titanium hydroxide gel) obtained by the reaction can also be used as a low condensate.

As the low condensate of the hydrolyzable titanium compound and the low condensate of titanium hydroxide, a compound having a condensation degree of 2 to 30 can be used, and a compound having a condensation degree of 2 to 10 is particularly preferable. If the degree of condensation is 30 or less, a stable titanium-containing aqueous liquid can be obtained by mixing with hydrogen peroxide.
The hydrolyzable titanium compounds, low condensates of hydrolysable titanium compounds, titanium hydroxide, and low condensates of titanium hydroxide can be used alone or in combination of two or more thereof. Tetraalkoxy titanium which is a hydrolyzable titanium compound represented by the formula is particularly preferable. The reason for this is that tetraalkoxytitanium does not affect the film performance such as corrosion resistance because the alcohol produced when hydrolyzed volatilizes in the process of drying the surface treatment liquid, and particularly excellent film performance is obtained. Because it is.

As the titanium-containing aqueous liquid (A), any conventionally known liquid can be used without particular limitation as long as it is an aqueous liquid containing titanium obtained by mixing the above-described titanium compound and hydrogen peroxide solution. Specifically, the following can be mentioned.
(I) A titanyl ion hydrogen peroxide complex or an aqueous solution of titanic acid (peroxotitanium hydrate) obtained by adding hydrogen peroxide to a hydrous titanium oxide gel or sol (JP-A 63-35419, JP-A 1-2224220 gazette).

(Ii) A liquid for forming a titania film obtained by synthesizing a titanium hydroxide gel produced from an aqueous solution of titanium chloride or titanium sulfate and a basic solution with a hydrogen peroxide solution (Japanese Patent Laid-Open No. 9-71418, (See Kaihei 10-67516).
When obtaining this titania film-forming liquid, titanium hydroxide gel called orthotitanic acid is precipitated by reacting an aqueous solution of titanium chloride or titanium sulfate having a salt-forming group with titanium and an alkaline solution such as ammonia or caustic soda. Let Next, the titanium hydroxide gel is separated by decantation with water, washed thoroughly with water, further added with hydrogen peroxide water, and excess hydrogen peroxide is decomposed and removed, whereby a yellow transparent viscous liquid can be obtained.

The precipitated orthotitanic acid is in a gel state polymerized by polymerization of OH or hydrogen bonds, and cannot be used as an aqueous liquid containing titanium as it is. When hydrogen peroxide solution is added to this gel, a part of OH is in a peroxidized state, dissolved as a peroxotitanate ion or in a kind of sol state in which the polymer chain is divided into low molecules, and excess hydrogen peroxide Is decomposed into water and oxygen, and can be used as an aqueous liquid containing titanium for forming an inorganic film.
Since this sol contains only oxygen and hydrogen atoms in addition to titanium atoms, when it is changed to titanium oxide by drying or firing, only water and oxygen are generated, so carbon components necessary for thermal decomposition such as sol-gel method and sulfate Further, it is not necessary to remove the halogen component, and a titanium oxide film having a relatively high density can be formed even at a low temperature.

(Iii) Hydrogen peroxide is added to an aqueous solution of an inorganic titanium compound such as titanium chloride or titanium sulfate to form peroxotitanium hydrate, and then the solution obtained by adding a basic substance is allowed to stand or be heated. A titanium oxide forming solution obtained by forming a precipitate of a titanium hydrate polymer, and then removing hydrogen and other dissolved components derived from at least a titanium-containing raw material solution (Japanese Patent Application Laid-Open 2000-247638, JP-A-2000-247639).

The titanium-containing aqueous liquid (A) using a hydrolyzable titanium compound and / or a low condensate thereof as a titanium compound (hereinafter referred to as “hydrolyzable titanium compound a” for convenience of explanation) contains hydrolyzable titanium compound a. It can be obtained by reacting with hydrogen oxide water at a reaction temperature of 1 to 70 ° C. for about 10 minutes to 20 hours.
In the titanium-containing aqueous liquid (A) using the hydrolyzable titanium compound a, the hydrolyzable titanium compound a is hydrolyzed with water by reacting the hydrolyzable titanium compound a with hydrogen peroxide. A product obtained by producing a hydroxyl group-containing titanium compound and then coordinating hydrogen peroxide to this hydroxyl group-containing titanium compound, and this hydrolysis reaction and coordination by hydrogen peroxide occur simultaneously. It produces a chelate solution that is extremely stable at room temperature and can withstand long-term storage. The titanium hydroxide gel used in the conventional manufacturing method is partially three-dimensionalized by Ti—O—Ti bonds, and the titanium-containing aqueous liquid (A) obtained by reacting this gel with hydrogen peroxide is composition and stable. Sex is essentially different.

  Further, when the titanium-containing aqueous liquid (A) using the hydrolyzable titanium compound a is heated or autoclaved at 80 ° C. or higher, a titanium oxide dispersion containing ultrafine particles of crystallized titanium oxide is obtained. If the heat treatment or autoclave treatment is performed at 80 ° C. or higher, the crystallization of titanium oxide can be sufficiently advanced. The average particle diameter of the titanium oxide ultrafine particles of the titanium oxide dispersion produced in this manner is 10 nm or less, preferably about 1 to 6 nm. When the average particle diameter of the titanium oxide ultrafine particles is 10 nm or less, the film-forming property is excellent (when the film is dried after coating to form a film, cracking does not occur when the film thickness is 1 μm or more). Moreover, it is preferable if the average particle diameter of the titanium oxide ultrafine particles is 1 nm or more because the surface treatment liquid can be maintained in a state where the viscosity does not increase. The appearance of this titanium oxide dispersion is translucent. Such a titanium oxide dispersion can also be used as the titanium-containing aqueous liquid (A).

The surface treatment liquid containing the titanium-containing aqueous liquid (A) using the hydrolyzable titanium compound a is coated and dried on the surface of the plated steel sheet (for example, heat-dried at a low temperature), thereby providing excellent adhesion by itself. A dense titanium oxide-containing film (surface treatment film) can be formed.
The heating temperature of the steel sheet after applying the surface treatment liquid is preferably, for example, 200 ° C. or less, particularly 150 ° C. or less. By heating and drying at such a temperature, an amorphous (amorphous) oxidation slightly containing hydroxyl groups is performed. A titanium-containing film can be formed.
In addition, when the titanium oxide dispersion obtained through the heat treatment at 80 ° C. or higher as described above or the autoclave treatment is used as the titanium-containing aqueous liquid (A), the crystalline titanium oxide can be obtained simply by applying the surface treatment liquid. Since a containing film can be formed, it is useful as a coating material for materials that cannot be heat-treated.

Further, as the titanium-containing aqueous liquid (A), a titanium-containing aqueous liquid (A1) obtained by reacting the hydrolyzable titanium compound a with hydrogen peroxide in the presence of a titanium oxide sol can also be used. .
The titanium oxide sol is a sol in which amorphous titania fine particles and / or anatase type titania fine particles are dispersed in water (for example, an aqueous organic solvent such as an alcohol or alcohol ether may be added if necessary). As this titanium oxide sol, conventionally known ones can be used. For example, (i) a titanium oxide aggregate obtained by hydrolyzing a titanium-containing solution such as titanium sulfate or titanyl sulfate, (ii) titanium alkoxide, etc. Titanium oxide aggregates obtained by hydrolyzing organic titanium compounds of the above, (iii) Titanium oxide aggregates obtained by hydrolyzing or neutralizing titanium halide solutions such as titanium tetrachloride, etc. An amorphous titania sol dispersed in water, or a sol in which the titanium oxide aggregates are calcined to form anatase-type titanium fine particles and this is dispersed in water can be used.

  In the firing of the amorphous titania, the amorphous titania can be converted into anatase titania by firing at a temperature at least higher than the crystallization temperature of anatase, for example, 400 ° C. to 500 ° C. or more. Examples of the aqueous sol of titanium oxide include, for example, TKS-201 (trade name, manufactured by TEIKA CORPORATION, anatase crystal form, average particle diameter 6 nm), TA-15 (trade name, manufactured by NISSAN CHEMICAL CO., LTD., Anatase crystal form). STS-11 (trade name, manufactured by Ishihara Sangyo Co., Ltd., anatase type crystal form) and the like.

  In the titanium-containing aqueous liquid (A1), the mass ratio x / y between the titanium oxide sol x and the titanium hydrogen peroxide reactant y (reaction product of the hydrolyzable titanium compound a and hydrogen peroxide solution) is 1 / A range of 99 to 99/1, preferably about 10/90 to 90/10 is suitable. If the mass ratio x / y is 1/99 or more, the effect of adding the titanium oxide sol is sufficiently obtained in terms of stability, photoreactivity, and the like, and if it is 99/1 or less, excellent film formation is achieved. It is preferable because of its property.

The titanium-containing aqueous liquid (A1) can be obtained by reacting the hydrolyzable titanium compound a with hydrogen peroxide at a reaction temperature of 1 to 70 ° C. for about 10 minutes to 20 hours in the presence of a titanium oxide sol.
The production form and characteristics of the titanium-containing aqueous liquid (A1) are the same as those of the titanium-containing aqueous liquid (A) using the hydrolyzable titanium compound a described above, but in particular, by using a titanium oxide sol. , It is possible to suppress a partial condensation reaction during the synthesis to increase the viscosity. The reason is considered to be that the condensation reaction product is adsorbed on the surface of the titanium oxide sol, and polymerization in a solution state is suppressed.

  Further, when the titanium-containing aqueous liquid (A1) is heated or autoclaved at 80 ° C. or higher, a titanium oxide dispersion containing ultrafine particles of crystallized titanium oxide is obtained. The titanium-containing aqueous liquid (A) using the hydrolyzable titanium compound a described above also describes the temperature conditions for obtaining this titanium oxide dispersion, the particle diameter of the crystallized titanium oxide ultrafine particles, the appearance of the dispersion, etc. It is the same. Such a titanium oxide dispersion can also be used as the titanium-containing aqueous liquid (A1).

Similar to the titanium-containing aqueous liquid (A) using the hydrolyzable titanium compound a described above, the surface treatment liquid containing the titanium-containing aqueous liquid (A1) is applied to the surface of the plated steel sheet and dried (for example, heated at a low temperature). By drying, it is possible to form a dense titanium oxide-containing film (surface treatment film) excellent in adhesion by itself.
The heating temperature of the steel sheet after applying the surface treatment liquid is preferably, for example, 200 ° C. or less, particularly 150 ° C. or less. By heating and drying at such a temperature, an anatase-type titanium oxide-containing film containing some hydroxyl groups can be obtained. Can be formed.
As described above, of the titanium-containing aqueous liquid (A), the titanium-containing aqueous liquid (A) and the titanium-containing aqueous liquid (A1) using the hydrolyzable titanium compound a are excellent in storage stability, corrosion resistance, and the like. It is particularly preferable to use these in the present invention.

The compounding ratio of hydrogen peroxide water to at least one titanium compound selected from hydrolyzable titanium compounds, hydrolyzable titanium compound low condensates, titanium hydroxide, titanium hydroxide low condensates is titanium compounds It is preferably 0.1 to 100 parts by mass, preferably 1 to 20 parts by mass in terms of hydrogen peroxide with respect to 10 parts by mass. If the blending ratio of hydrogen peroxide water is 0.1 parts by mass or more in terms of hydrogen peroxide, chelate formation is sufficient so that no cloudy precipitation occurs. On the other hand, if it is 100 parts by mass or less, unreacted This is preferable because no hydrogen peroxide remains, and no active oxygen is released during storage.
The hydrogen peroxide concentration of the hydrogen peroxide solution is not particularly limited, but it is preferably about 3 to 30% by mass from the viewpoint of ease of handling and the solid content of the product liquid related to coating workability.

Other sols and pigments can be added and dispersed in the titanium-containing aqueous liquid (A) as necessary. Examples of the additive include commercially available titanium oxide sol, titanium oxide powder, mica, talc, barita, clay, and the like, and one or more of these can be added.
The content of the titanium-containing aqueous liquid (A) in the surface treatment liquid is preferably 1 to 100 g / L, preferably 5 to 50 g / L in terms of solid content, from the viewpoint of the stability of the treatment liquid.

・ Organic phosphate compounds (B)
Examples of the organic phosphate compound (B) include 1-hydroxymethane-1,1-diphosphonic acid, 1-hydroxyethane-1,1-diphosphonic acid, 1-hydroxypropane-1,1-diphosphonic acid, and the like. Suitable examples include hydroxyl group-containing organic phosphorous acid; carboxyl group-containing organic phosphorous acid such as 2-hydroxyphosphonoacetic acid, 2-phosphonobutane-1,2,4-tricarboxylic acid, and salts thereof. These 1 type (s) or 2 or more types can be used.

The organic phosphoric acid compound (B) has an effect of improving the corrosion resistance and the storage stability of the titanium-containing aqueous liquid (A). Among them, 1-hydroxyethane-1,1-diphosphonic acid has a particularly large effect. Therefore, it is particularly preferable to use this.
The compounding amount of the organic phosphoric acid compound (B) is 1 to 400 parts by mass, preferably 20 to 350 parts by mass with respect to 100 parts by mass of the solid content of the titanium-containing aqueous liquid (A). When the compounding amount of the organic phosphoric acid compound (B) is less than 1 part by mass with respect to 100 parts by mass of the solid content of the titanium-containing aqueous liquid (A), the corrosion resistance and adhesion are inferior. On the other hand, when it exceeds 400 parts by mass, the water-resistant adhesion is inferior.

・ Vanadic acid compound (C)
The vanadate compound (C) is to improve the anticorrosive property of the film formed by the surface treatment liquid, for example, vanadate, lithium orthovanadate, sodium orthovanadate, lithium metavanadate, potassium metavanadate, Examples include sodium metavanadate, ammonium metavanadate, sodium pyrovanadate, vanadyl chloride, and vanadyl sulfate, and one or more of these can be used. Among these, metavanadate having a large effect on corrosion resistance is preferable, and ammonium metavanadate is particularly preferable.

  The compounding amount of the vanadic acid compound (C) is 1 to 500 parts by mass, preferably 10 to 10 parts by mass with respect to 100 parts by mass of the solid content of the titanium-containing aqueous liquid (A) from the viewpoint of corrosion resistance after alkaline degreasing of the film. 400 parts by mass. When the compounding amount of the vanadic acid compound (C) is less than 1 part by mass with respect to 100 parts by mass of the solid content of the titanium-containing aqueous liquid (A), the corrosion resistance after alkali degreasing is poor. On the other hand, when it exceeds 500 mass parts, since V exists excessively, sufficient corrosion resistance cannot be expressed.

・ Zirconium carbonate compound (D)
Examples of the zirconium carbonate compound (D) include salts of zirconium carbonate such as sodium, potassium, lithium and ammonium (for example, ammonium zirconium carbonate, sodium zirconium carbonate, lithium zirconium carbonate), and one or more of these. Can be used. Of these, ammonium zirconium carbonate is preferable from the viewpoint of water-resistant adhesion.
The compounding amount of the zirconium carbonate compound (D) is preferably more than 400 parts by mass and not more than 1000 parts by mass with respect to 100 parts by mass of the solid content of the titanium-containing aqueous liquid (A), from the viewpoint of corrosion resistance after alkaline degreasing of the film. Is 450 to 900 parts by mass. When the compounding amount of the zirconium carbonate compound (D) is 400 parts by mass or less with respect to 100 parts by mass of the solid content of the titanium-containing aqueous liquid (A), the corrosion resistance after alkali degreasing is poor. On the other hand, when it exceeds 1000 parts by mass, Zr is excessively present and sufficient corrosion resistance cannot be expressed.

・ Silane coupling agent (E)
Examples of the silane coupling agent (E) include N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, and γ-methacryloxypropyltrimethoxy. Silane, N-β (N-vinylbenzylaminoethyl) γ-aminopropyltrimethoxysilane-hydrochloride, γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, Methyltrimethoxysilane, vinyliritriacetoxysilane, γ-chloropropyltrimethoxysilane, hexamethyldisilazane, γ-anilinopropyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, octadecyldimethyl [3- (to Trimethoxysilyl) propyl] ammonium chloride, etc. trimethylchlorosilane and the like, can be used alone or in combination of two or more thereof. Among them, by using a coupling agent having a glycidyl group such as γ-glycidoxypropyltrimethoxysilane, an organic component (for example, organic phosphoric acid) -inorganic component (for example, titanium-containing aqueous liquid in the film). The adhesion of the derived titanium compound is increased and the corrosion resistance is further improved.

  The blending amount of the silane coupling agent (E) is 5 to 50% by mass, preferably 10 to 40% by mass in terms of the total solid content of the surface treatment liquid, from the viewpoint of corrosion resistance after the film is alkali degreased. And When the amount of the silane coupling agent (E) is less than 5% by mass in the total solid content of the surface treatment liquid, the corrosion resistance after alkali degreasing is poor. On the other hand, if it exceeds 50% by mass, the liquid stability is lowered and the cost is increased.

・ Water-soluble organic resin and / or water-dispersible organic resin (F)
If necessary, the surface treatment liquid (α) used in the present invention may further contain a water-soluble organic resin and / or a water-dispersible organic resin (F). This water-soluble organic resin and / or water-dispersible organic resin (F) is an organic resin that can be dissolved or dispersed in water, and a method for water-solubilizing or dispersing the organic resin in water is conventionally known. The method can be applied. Specifically, the organic resin contains a functional group (for example, a hydroxyl group, a polyoxyalkylene group, a carboxyl group, an amino (imino) group, a sulfide group, a phosphine group, etc.) that can be water-soluble or water-dispersed independently. , And if necessary, part or all of these functional groups are amine compounds such as ethanolamine and triethylamine if acidic resin (carboxyl group-containing resin, etc.); ammonia water; lithium hydroxide, sodium hydroxide, water Neutralized with alkali metal hydroxides such as potassium oxide, and fatty acids such as acetic acid and lactic acid for basic resins (amino group-containing resins); those neutralized with mineral acids such as phosphoric acid Can be used.

Examples of water-soluble or water-dispersible organic resins include epoxy resins, phenolic resins, acrylic resins, urethane resins, olefin-carboxylic acid resins, nylon resins, resins having a polyoxyalkylene chain, and polyvinyl alcohol. , Polyglycerin, carboxymethylcellulose, hydroxymethylcellulose, hydroxyethylcellulose and the like. The said organic resin can use 1 type (s) or 2 or more types.
Among these, it is particularly preferable from the viewpoint of the storage stability of the surface treatment liquid to use at least one organic resin selected from water-soluble or water-dispersible acrylic resins, urethane resins and epoxy resins. In particular, it is preferable to use a water-soluble or water-dispersible acrylic resin as a main component from the viewpoint of the balance between the storage stability of the surface treatment liquid and the coating film performance.

A water-soluble or water-dispersible acrylic resin is prepared by a conventionally known method, for example, an emulsion polymerization method, a suspension polymerization method, a polymer having a hydrophilic group by solution polymerization, and neutralized or made aqueous if necessary. Or the like.
The polymer having a hydrophilic group includes, for example, an unsaturated monomer having a hydrophilic group such as a carboxyl group, an amino group, a hydroxyl group, and a polyoxyalkylene group, and, if necessary, other unsaturated monomers. It can be obtained by polymerizing the monomer.
The water-soluble or water-dispersible acrylic resin is preferably one obtained by copolymerizing styrene from the viewpoint of corrosion resistance, and the amount of styrene in the total unsaturated monomer is 10 to 60% by mass, particularly 15 to 50% by mass. It is preferable that Moreover, it is preferable from points, such as toughness of the film obtained, that Tg (glass transition point) of the acrylic resin obtained by copolymerization is 30-80 degreeC, especially 35-70 degreeC.

Examples of the carboxyl group-containing unsaturated monomer include acrylic acid, methacrylic acid, maleic acid, maleic anhydride, crotonic acid, and itaconic acid.
Examples of the nitrogen-containing unsaturated monomer such as the amino group-containing unsaturated monomer include N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, Nt- Nitrogen-containing alkyl (meth) acrylates such as butylaminoethyl (meth) acrylate; acrylamide, methacrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-methylol (meth) acrylamide, N-methoxymethyl Polymerization of (meth) acrylamide, N-butoxymethyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, N, N-dimethylaminoethyl (meth) acrylamide, etc. Amides; 2-vinylpyridine, - vinyl-2-pyrrolidone, aromatic nitrogen-containing monomers such as 4-vinylpyridine; and allylamine and the like.

  Examples of the hydroxyl group-containing unsaturated monomer include 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, 2,3-dihydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, polyethylene glycol mono Monoesterified product of polyhydric alcohol such as (meth) acrylate, polypropylene glycol mono (meth) acrylate and acrylic acid or methacrylic acid; ε-caprolactone is opened to monoesterified product of polyhydric alcohol and acrylic acid or methacrylic acid. Examples include a ring-polymerized compound.

Other unsaturated monomers include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, 1 carbon number such as tert-butyl (meth) acrylate, 2-ethylhexyl acrylate, n-octyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, octadecyl (meth) acrylate, isostearyl (meth) acrylate -24 alkyl (meth) acrylates; vinyl acetate and the like.
The unsaturated monomer mentioned above can use 1 type (s) or 2 or more types. In the description of the present application, “(meth) acrylate” means “acrylate or methacrylate”.

  Examples of the urethane-based resin include a chain extender which is a low molecular weight compound having two or more active hydrogens such as a diol and a diamine as needed, and a polyurethane composed of a polyol and a diisocyanate such as polyester polyol and polyether polyol. Those which are chain-extended in the presence and stably dispersed or dissolved in water can be suitably used, and conventionally known ones can be widely used (for example, Japanese Patent Publication No. 42-24192, Japanese Patent Publication No. 42-24194, (See JP-B-42-5118, JP-B-49-986, JP-B-49-33104, JP-B-50-15027, JP-B-53-29175).

As a method for stably dispersing or dissolving the polyurethane resin in water, for example, the following method can be used.
(1) A method of imparting hydrophilicity by introducing an ionic group such as a hydroxyl group, an amino group or a carboxyl group into the side chain or terminal of a polyurethane polymer, and dispersing or dissolving in water by self-emulsification.
(2) A polyurethane polymer whose reaction has been completed or a polyurethane polymer whose terminal isocyanate group has been blocked with a blocking agent such as oxime, alcohol, phenol, mercaptan, amine, sodium bisulfite, etc. is forcibly submerged in water using an emulsifier and mechanical shearing force. How to disperse. Further, a method in which a urethane polymer having a terminal isocyanate group is mixed with water, an emulsifier and a chain extender, and dispersion and high molecular weight are simultaneously performed using mechanical shearing force.
(3) A method in which a water-soluble polyol such as polyethylene glycol is used as a polyol as a main polyurethane material, and is dispersed or dissolved in water as a water-soluble polyurethane.
In addition, what was obtained by the different method among the dispersion | distribution or melt | dissolution methods mentioned above can also mix and use a polyurethane-type resin.

Examples of the diisocyanate that can be used for the synthesis of the polyurethane resin include aromatic, alicyclic or aliphatic diisocyanates. Specifically, hexamethylene diisocyanate, tetramethylene diisocyanate, 3,3′-dimethoxy-4, 4'-biphenylene diisocyanate, p-xylylene diisocyanate, m-xylylene diisocyanate, 1,3- (diisocyanatomethyl) cyclohexanone, 1,4- (diisocyanatomethyl) cyclohexanone, 4,4'-diisocyanato Cyclohexanone, 4,4'-methylenebis (cyclohexyl isocyanate), isophorone diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, p-phenylene diisocyanate, diphenylmethane di Isocyanate, m- phenylene diisocyanate, 2,4-naphthalene diisocyanate, 3,3'-dimethyl-4,4'-biphenylene diisocyanate, 4,4'-biphenylene diisocyanate and the like. Among these, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate are particularly preferable.
Examples of commercially available polyurethane resins include Hydran HW-330, HW-340, HW-350 (both trade names, manufactured by Dainippon Ink and Chemicals), Superflex 100, 150, E-2500, F-3438D (all are trade names, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.).

  As the epoxy resin, a cationic epoxy resin obtained by adding an amine to an epoxy resin; a modified epoxy resin such as an acrylic modification or a urethane modification can be preferably used. Examples of cationic epoxy resins include adducts of epoxy compounds with primary mono- or polyamines, secondary mono- or polyamines, and primary and secondary mixed polyamines (see, for example, US Pat. No. 3,984,299). An adduct of an epoxy compound and a secondary mono- or polyamine having a ketiminated primary amino group (see, for example, US Pat. No. 4,017,438); an epoxy compound having a ketiminated primary amino group Examples include etherification reaction products with hydroxyl compounds (see, for example, JP-A-59-43013).

  As the epoxy resin, those having a number average molecular weight of 400 to 4000, particularly 800 to 2000, and an epoxy equivalent of 190 to 2000, particularly 400 to 1000 are preferable. Such an epoxy resin can be obtained, for example, by a reaction between a polyphenol compound and epirulhydrin, and examples of the polyphenol compound include bis (4-hydroxyphenyl) -2,2-propane, 4,4. -Dihydroxybenzophenone, bis (4-hydroxyphenyl) -1,1-ethane, bis (4-hydroxyphenyl) -1,1-isobutane, bis (4-hydroxy-tert-butylphenyl) -2,2-propane, Bis (2-hydroxynaphthyl) methane, 1,5-dihydroxynaphthalene, bis (2,4-dihydroxyphenyl) methane, tetra (4-hydroxyphenyl) -1,1,2,2-ethane, 4,4-dihydroxy Diphenylsulfone, phenol novolak, cresol novolak, etc. That.

  The compounding quantity of water-soluble organic resin or / and water-dispersible organic resin (F) is 10-2000 mass parts with respect to 100 mass parts of solid content of a titanium containing aqueous liquid (A), especially 100-1500 weight parts. It is preferable from the viewpoint of corrosion resistance after alkali degreasing the film. That is, when the blending amount of the water-soluble organic resin and / or water-dispersible organic resin (F) is 10 parts by mass or more with respect to 100 parts by mass of the solid content of the titanium-containing aqueous liquid (A), In addition, the effect of improving the corrosion resistance after alkaline degreasing by adding the water-dispersible organic resin (F) is sufficiently obtained. On the other hand, when the amount is 2000 parts by mass or less, the heat discoloration and adhesion after processing can be secured.

If necessary, organic fine particles and / or inorganic fine particles can be further added to the surface treatment liquid (α). By adding such fine particles, the transparency of the coating film is lowered, and nitrite (interference color) that tends to occur in the thin film can be suppressed, and thus a surface-treated film suitable for applications in which appearance is important can be obtained. The average particle diameter of the fine particles is preferably 3 to 1000 nm, particularly 3 to 500 nm, from the viewpoint of sedimentation stability and corrosion resistance of the particles.
Examples of the organic fine particles include resin fine particles such as acrylic, polyurethane, nylon, and polyethylene glycol. Examples of the inorganic fine particles include silica, titanium dioxide, barium sulfate, and calcium carbonate. From the viewpoint of cost, silica, titanium dioxide, barium sulfate and the like are preferable.
The addition amount of the organic fine particles and / or inorganic fine particles is preferably 1 to 30% by mass, particularly 1 to 20% by mass in terms of the total solid content of the surface treatment liquid, from the viewpoint of corrosion resistance and the like.

If necessary, the surface treatment liquid (α) may contain, in addition to the above-described components, for example, heavy metal compounds other than the components of the present invention, aqueous organic polymer compounds, thickeners, surfactants, rust inhibitors (tannins). Acid, phytic acid, benzotriazole, etc.), color pigments, extender pigments, silica, rust preventive pigments and the like.
Since the surface treatment liquid (α) becomes a stable liquid in a neutral or acidic region, the pH is preferably 1 to 7, and particularly preferably 1 to 5.
The surface treatment liquid (α) is usually diluted with water and used, but if necessary, it is diluted with a hydrophilic solvent such as methanol, ethanol, isopropyl alcohol, ethylene glycol, or propylene glycol. May be.
The film thickness (dry film thickness) of the first layer film formed by the surface treatment liquid (α) as described above is 0 in order to achieve both economic efficiency and coating film performance, particularly corrosion resistance and conductivity at a high level. 0.01 to 1.5 μm, desirably 0.05 to 1.0 μm is preferable.

[Second layer coating]
Hereinafter, the second layer coating formed on the surface of the first layer coating and the surface treatment liquid (β) for forming the coating will be described.
Although the first layer coating can give good corrosion resistance to galvanized steel plates or aluminum-based plated steel plates, the rust-preventive component is excessively eluted in the single-layer coating, satisfying the required corrosion resistance depending on the application. It is also assumed that it is difficult to do. Therefore, in the present invention, the surface treatment liquid (β) is applied to the surface of the first layer coating and dried to form the second layer coating. The second layer coating derived from the surface treatment liquid (β) is an organic resin layer. In the present invention, excessive component elution from the first layer coating is reduced, and the corrosion resistance (chemical resistance, mold resistance) of the surface treated steel sheet is reduced. It plays a role of reinforcing galling, fingerprint resistance, design, etc.). A 2nd layer membrane | film | coat is formed by adjusting to the film thickness of the grade which does not impair the electroconductivity of a surface treatment steel plate, and, thereby, the surface treatment steel plate provided with the outstanding electroconductivity and corrosion resistance in a good balance is obtained.

  The surface treatment liquid (β) preferably contains an organic resin (G) as a main component. Various organic resins (G) can be used. For example, epoxy resin, modified epoxy resin, urethane resin, alkyd resin, acrylic resin, ethylene resin (polyolefin resin), polyester resin, polybutadiene resin, amino resin The type of phenol resin, fluorine resin, silicon resin, etc. is not limited. In addition, about 50-90 mass% is suitable for content of organic resin (G) in the ratio in the total solid of surface treatment liquid ((beta)).

As described above, in order to impart corrosion resistance to the surface-treated steel sheet, it is effective to reduce excessive component elution from the first layer coating. Therefore, in the present invention, regardless of the type of organic resin (G) contained in the surface treatment liquid (β), the second layer film is formed to protect the first layer film and reinforce the corrosion resistance of the surface treated steel sheet. To do.
Here, as the organic resin (G) to be included in the surface treatment liquid (β), an organic resin (H) having an OH group and / or a COOH group, or a hydrazine-modified organic resin (K) as shown below is used. It is particularly suitable, and by using these, a second layer film having particularly excellent performance can be obtained.

.Organic resin having OH group and / or COOH group (H)
In the present invention, by using a surface treatment liquid (β) containing an organic resin (H) having an OH group and / or a COOH group (hereinafter sometimes simply referred to as “organic resin (H)”), Excellent adhesion between the first layer coating and the second layer coating is obtained, and as a result, a surface-treated steel sheet having particularly excellent corrosion resistance can be obtained.
Examples of the organic resin (H) having an OH group and / or a COOH group include an epoxy resin (H1), a modified epoxy resin (H2), a polyhydroxy polyether resin (H3), and a urethane resin (H4) as shown below. ), Alkyd resin (H5), acrylic resin (H6), ethylene copolymer (H7), acrylic silicon resin (H8), fluororesin copolymer (H9), and the like.

  Examples of the epoxy resin (H1) include epoxy resins obtained by glycidyl etherification of bisphenol A, bisphenol F, novolac, etc., epoxy resins obtained by adding propylene oxide, ethylene oxide or polyalkylene glycol to bisphenol A, and further, Aliphatic epoxy resins, alicyclic epoxy resins, polyether epoxy resins, and the like can be used. In addition, when forming a second layer film by heating and drying a surface treatment solution containing an epoxy resin, particularly when a film formation in a low temperature region is required, an epoxy resin having a number average molecular weight of 1500 or more is desirable. In addition, the said epoxy resin can also be used individually or in mixture of a different kind.

  Examples of the modified epoxy resin (H2) include resins obtained by reacting various modifiers with the epoxy group or hydroxyl group in the epoxy resin, and specifically, a dry oil fatty acid on the epoxy group or hydroxyl group. An epoxy ester resin obtained by reacting a carboxyl group therein, an epoxy acrylate resin obtained by reacting acrylic acid or methacrylic acid with the epoxy group or hydroxyl group, a urethane-modified epoxy resin obtained by reacting an isocyanate compound with the epoxy group or hydroxyl group, Examples thereof include an amine-added urethane-modified epoxy resin obtained by adding an alkanolamine to a urethane-modified epoxy resin obtained by reacting an epoxy compound with an isocyanate compound.

The polyhydroxy polyether resin (H3) comprises a mononuclear or binuclear dihydric phenol or a mixed dihydric phenol of mononuclear and binuclear types in the presence of an alkali catalyst in an approximately equimolar amount of epihalohydrin. It is a polymer obtained by polycondensation. Representative examples of mononuclear dihydric phenols include resorcin, hydroquinone, and catechol, and representative examples of binuclear phenols include bisphenol A. These may be used alone or in combination of two or more.
Examples of the urethane resin (H4) include an oil-modified polyurethane resin, an alkyd polyurethane resin, a polyester polyurethane resin, a polyether urethane resin, and a polycarbonate polyurethane resin.
Examples of the alkyd resin (H5) include oil-modified alkyd resins, rosin-modified alkyd resins, phenol-modified alkyd resins, styrenated alkyd resins, silicon-modified alkyd resins, acrylic-modified alkyd resins, oil-free alkyd resins, and high molecular weight oil-free resins. An alkyd resin etc. can be mentioned.

Examples of the acrylic resin (H6) include polyacrylic acid and its copolymer, polyacrylic acid ester and its copolymer, polymethacrylic acid and its copolymer, polymethacrylic acid ester and its copolymer, Examples include urethane-acrylic acid copolymers (or urethane-modified acrylic resins), styrene-acrylic acid copolymers, etc., and further using resins obtained by modifying these resins with other alkyd resins, epoxy resins, phenol resins, etc. May be.
Examples of the ethylene copolymer (H7) include ethylene copolymers such as ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, carboxyl-modified polyolefin resin, and ethylene-unsaturated carboxylic acid copolymer. Examples of the resin include ethylene ionomers, and resins obtained by modifying these resins with other alkyd resins, epoxy resins, phenol resins, or the like.

Examples of the acrylic silicon resin (H8) include those containing a hydrolyzable alkoxysilyl group as a main agent in the side chain or terminal of an acrylic copolymer and added with a curing agent. When these acrylic silicon resins are used, excellent weather resistance can be expected.
Examples of the fluororesin copolymer (H9) include fluoroolefin copolymers, which include, for example, alkyl vinyl ether, cycloalkyl vinyl ether, carboxylic acid-modified vinyl ester, hydroxyalkyl allyl ether, tetrafluoropropyl as monomers. There is a copolymer obtained by copolymerizing vinyl ether or the like with a fluorine monomer (fluoroolefin). When these fluororesin-based copolymers are used, excellent weather resistance and excellent hydrophobicity can be expected.

  The organic resin (H) is preferably a thermosetting resin, and among them, a thermosetting epoxy resin or a modified epoxy resin having an excellent blocking property against a corrosion factor such as oxygen is optimal. When the second layer film is formed using the surface treatment liquid (β) containing these organic resins (H), a surface-treated steel sheet having desired corrosion resistance can be obtained even if the film thickness is thin. Therefore, it is particularly advantageous when emphasizing the conductivity and spot weldability of the surface-treated steel sheet and suppressing the amount of coating film to a low level.

  From the viewpoint of corrosion resistance, workability, and paintability, among the organic resins (H) described above, epoxy resin (H1), modified epoxy resin (H2), and ethylene-based copolymer (H7) are used. Particularly preferred are thermosetting epoxy resins and modified epoxy resins having excellent blocking properties against corrosion factors such as enzymes. These thermosetting resins include thermosetting epoxy resins, thermosetting modified epoxy resins, acrylic copolymer resins copolymerized with epoxy group-containing monomers, polybutadiene resins having epoxy groups, and polyurethane resins having epoxy groups. , And adducts or condensates of these resins. One of these epoxy group-containing resins can be used alone or in admixture of two or more.

Besides the above (H1) to (H9), as the organic resin (G), polybutadiene resin, phenol resin, polyamine resin, polyphenylene resin, or the like can be used. Also, a mixture or addition polymer obtained by mixing two or more of the resins described above can be used.
In addition, for the purpose of lowering the heat drying temperature of the resin, a core-shell type water-dispersible resin made of a resin having a different resin type or a resin having a different glass transition temperature can be used in the core part and the shell part of the resin particle. .
In addition, by using a water-dispersible resin having self-crosslinkability, for example, by adding an alkoxysilane group to the resin particles, silanol groups are generated by hydrolysis of the alkoxysilane when the resin is heated and dried, and silanol groups between the resin particles Interparticle cross-linking utilizing the dehydration condensation reaction can be used.

Further, as the organic resin (G), an organic composite silicate in which an organic resin is combined with silica through a silane coupling agent is also suitable.
In addition, from the viewpoint of improving the corrosion resistance and workability of the second layer coating, as described above, the thermosetting resin is particularly preferable as the organic resin (H). However, when this is used, the organic resin (H ), Hardeners such as urea resins (butylated urea resins, etc.), melamine resins (butylated melamine resins, etc.), butylated urea / melamine resins, benzoguanamine resins, etc., blocked isocyanates, oxazoline compounds, phenol resins, etc. It can also be blended.

  When the second layer film is formed using the surface treatment liquid (β) containing the organic resin (H) described above, the adhesion between the first layer film and the second layer film is improved, and as a result, the first layer Excess elution of the film components is suppressed, and a surface-treated steel sheet having further excellent corrosion resistance can be obtained. The reason why such an effect is obtained is not necessarily clear, but the organic resin (H) having an OH group and / or a COOH group (preferably a thermosetting resin, more preferably an epoxy resin and / or a modified epoxy resin) is used. It is presumed that a dense barrier film is formed by reaction with a curing agent (crosslinking agent), and this barrier film expresses an excellent permeation suppressing ability against corrosion factors such as oxygen. In addition, since this barrier film is firmly bonded to the titanium compound and / or the organic phosphate compound that is the first layer film component, the OH group or COOH group in the molecule is formed between the first layer film and the second layer film. It is presumed that it will greatly contribute to the improvement of adhesion.

・ Hydrazine modified organic resin (K)
In the present invention, by using a surface treatment liquid (β) containing a hydrazine-modified organic resin (K), a surface-treated steel sheet having extremely good corrosion resistance can be obtained while minimizing the decrease in conductivity.
The hydrazine-modified organic resin (K) is produced by a reaction between a predetermined organic resin (X) and an active hydrogen-containing compound (J) made of a hydrazine derivative (I) partly or entirely having active hydrogen. As the kind of the organic resin (X), a part or all of the active hydrogen-containing compound reacts with the active hydrogen-containing compound (J) which is the hydrazine derivative (I) having active hydrogen, and the active hydrogen is added to the organic resin. There is no particular limitation as long as the containing compound (J) can be bonded by a reaction such as addition or condensation and can form a film appropriately. Examples of the organic resin (X) include epoxy resins, modified epoxy resins, polyurethane resins, polyester resins, alkyd resins, acrylic copolymer resins, polybutadiene resins, phenol resins, and adducts or condensates of these resins. One of these can be used alone, or two or more can be used in combination.

  The organic resin (X) is particularly preferably an epoxy group-containing resin (X1) containing an epoxy group in the resin from the viewpoints of reactivity, ease of reaction, corrosion resistance, and the like. As such an epoxy group-containing resin (X1), in addition to the epoxy resin (X1-1) and the modified epoxy resin (X1-2), for example, an acrylic copolymer resin (X1) copolymerized with an epoxy group-containing monomer -3), polybutadiene resins having an epoxy group, polyurethane resins having an epoxy group, and adducts or condensates of these resins. One of these epoxy group-containing resins can be used alone or two or more of them can be used. It can be used by mixing.

  Of these epoxy group-containing resins (X1), epoxy resin (X1-1) and modified epoxy resin (X1-2) are particularly suitable from the viewpoints of adhesion to the surface of the first layer film and corrosion resistance. Of these, thermosetting epoxy resins and modified epoxy resins having excellent barrier properties against corrosive factors such as oxygen are most suitable, and some or all of these epoxy group-containing resins (X1). A second layer film is formed using a surface treatment liquid (β) containing a hydrazine-modified organic resin (K) produced by a reaction with an active hydrogen-containing compound (J) comprising hydrazine derivative (I) having active hydrogen. By doing so, a surface-treated steel sheet with extremely good corrosion resistance can be obtained even if the film thickness is thin. Therefore, it is particularly advantageous when importance is attached to the conductivity and spot weldability of the surface-treated steel sheet and it is desired to suppress the coating amount to a low level.

  The epoxy resin (X1-1) is formed by reacting a polyphenol such as bisphenol A, bisphenol F, or novolak type phenol with an epihalohydrin such as epichlorohydrin to introduce a glycidyl group, or this glycidyl group introduction reaction product. Examples include aromatic epoxy resins obtained by further reacting polyphenols with the product to increase the molecular weight, and aliphatic epoxy resins and alicyclic epoxy resins. One of these may be used alone, or two or more may be mixed. Can be used. Moreover, the hydrazine modified organic resin (K) produced | generated by reaction with an epoxy resin (X1-1) and the active hydrogen containing compound (J) which a part or all compound consists of hydrazine derivative (I) which has active hydrogen. When the surface treatment liquid (β) containing is heated and dried to form the second film, particularly when it is necessary to form a film in a low temperature range, an epoxy resin (X1-1) having a number average molecular weight of 1500 or more is obtained. Is preferred.

このようなビスフェノールＡ型エポキシ樹脂の製造法は当業界において広く知られている。また、上記化学構造式において、qは０〜５０、好ましくは１〜４０、より好ましくは２〜２０である。 Particularly preferable as the epoxy resin (X1-1) is a resin having a chemical structure represented by the following formula (1), which is a reaction product of bisphenol A and epihalohydrin, and this epoxy resin is particularly excellent in corrosion resistance. Therefore, it is preferable.

A method for producing such a bisphenol A type epoxy resin is widely known in the art. Moreover, in the said chemical structural formula, q is 0-50, Preferably it is 1-40, More preferably, it is 2-20.

Examples of the modified epoxy resin (X1-2) include resins obtained by reacting various modifiers with epoxy groups or hydroxyl groups in the epoxy resin (X1-1). For example, a dry oil fatty acid is reacted. Examples thereof include an epoxy ester resin, 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.
Moreover, as the acrylic copolymer resin (X1-3) copolymerized with the epoxy group-containing monomer, an unsaturated monomer component having an epoxy group and an acrylic acid ester or a methacrylic acid ester are essential. And a resin synthesized by a solution polymerization method, an emulsion polymerization method, a suspension polymerization method, or the like.

  Examples of the polymerizable unsaturated monomer component include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-, iso- or tert-butyl (meth) acrylate, hexyl (meth) acrylate, C1-24 alkyl ester of acrylic acid or methacrylic acid such as 2-ethylhexyl (meth) acrylate, decyl (meth) acrylate, lauryl (meth) acrylate; acrylic acid, methacrylic acid, styrene, vinyltoluene, acrylamide, acrylonitrile, N- Examples thereof include methylol (meth) acrylamide, C1-4 alkyl etherified product of N-methylol (meth) acrylamide; N, N-diethylaminoethyl methacrylate and the like.

The unsaturated monomer having an epoxy group is not particularly limited as long as it has an epoxy group and a polymerizable unsaturated group, such as glycidyl methacrylate, glycidyl acrylate, and 3,4-epoxycyclohexylmethyl (meth) acrylate. .
Furthermore, the acrylic copolymer resin (X1-3) copolymerized with the epoxy group-containing monomer may be a resin modified with a polyester resin, an epoxy resin, a phenol resin, or the like.
The organic resin (X) may be any of an organic solvent dissolved type, an organic solvent dispersed type, a water soluble type, and a water dispersed type.

The hydrazine-modified organic resin (K) aims to give the hydrazine derivative (I) to the molecule of the organic resin (X), and therefore, at least a part of the active hydrogen-containing compound (J) (preferably All) must be hydrazine derivatives (I) having active hydrogen.
When the organic resin (X) is an epoxy group-containing resin (X1), examples of the active hydrogen-containing compound (J) that reacts with the epoxy group include the following, and one or more of these may be Can be used. Also in this case, at least a part (preferably all) of the active hydrogen-containing compound (J) needs to be the hydrazine derivative (J1) having active hydrogen (that is, the hydrazine derivative (I) described above).
・ Hydrazine derivative (J1) having active hydrogen (= hydrazine derivative (I))
.Primary or secondary amine compounds having active hydrogen (J2)
・ Organic acids such as ammonia and carboxylic acids (J3)
・ Hydrogen halides such as hydrogen chloride (J4)
・ Alcohols and thiols (J5)
・ A quaternary chlorinating agent (J6) which is a hydrazine derivative or a mixture of a tertiary amine and an acid having no active hydrogen

Examples of the hydrazine derivative (I) having active hydrogen include the following.
(1) Carbohydrazide, propionic acid hydrazide, salicylic acid hydrazide, adipic acid dihydrazide, sebacic acid dihydrazide, dodecanedioic acid dihydrazide, isophthalic acid dihydrazide, thiocarbohydrazide, 4,4'-oxybisbenzenesulfonyl hydrazide, N-benzophenone hydrazone Hydrazide compounds such as aminopolyacrylamide;
(2) pyrazole compounds such as pyrazole, 3,5-dimethylpyrazole, 3-methyl-5-pyrazolone, 3-amino-5-methylpyrazole;

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

(4) tetrazole compounds such as 5-phenyl-1,2,3,4-tetrazole and 5-mercapto-1-phenyl-1,2,3,4-tetrazole;
(5) thiadiazole compounds such as 2-amino-5-mercapto-1,3,4-thiadiazole, 2,5-dimercapto-1,3,4-thiadiazole;
(6) Maleic hydrazide, 6-methyl-3-pyridazone, 4,5-dichloro-3-pyridazone, 4,5-dibromo-3-pyridazone, 6-methyl-4,5-dihydro-3-pyridazone, etc. Pyridazine compounds Among these, pyrazole compounds and triazole compounds having a 5-membered or 6-membered ring structure and having a nitrogen atom in the ring structure are particularly suitable.
These hydrazine derivatives (I) can be used alone or in combination of two or more.

Typical examples of the amine compound (J2) having the active hydrogen that can be used as a part of the active hydrogen-containing compound (J) include the following.
(1) A primary amino group of an amine compound containing one secondary amino group and one or more primary amino groups, such as diethylenetriamine, hydroxyethylaminoethylamine, ethylaminoethylamine, and methylaminopropylamine, A compound modified with aldimine, ketimine, oxazoline or imidazoline by heat reaction with aldehyde or carboxylic acid at a temperature of about 100 to 230 ° C., for example;

(2) Secondary monoamines such as diethylamine, diethanolamine, di-n- or -iso-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) A compound obtained by modifying a primary amino group of an alkanolamine such as monoethanolamine, neopentanolamine, 2-aminopropanol, 3-aminopropanol, 2-hydroxy-2 ′ (aminopropoxy) ethyl ether to ketimine;

Examples of the organic acid (J3) that can be used as a part of the active hydrogen-containing compound (J) include formic acid, acetic acid, propionic acid, butyric acid, caproic acid, lauric acid, palmitic acid, stearic acid, oleic acid, linolenic acid, and shu Examples include acid, malonic acid, succinic acid, glutaric acid, benzoic acid, phthalic acid, gallic acid, terephthalic acid, isophthalic acid, salicylic acid, lactic acid, citric acid, maleic acid, and adipic acid.
Examples of the hydrogen halide (J4) that can be used as part of the active hydrogen-containing compound (J) include hydrogen fluoride, hydrogen bromide, and hydrogen iodide.
Examples of the alcohols and thiols (J5) that can be used as part of the active hydrogen-containing compound (J) include methanol, ethanol, propanol, propan-2-ol, butanol, phenylmethanol, propane-1,2-diol, Examples include ethanethiol, butane-2,3-dithiol, and 3-mercapto-2-butanol.

The quaternary chlorinating agent (J6), which can be used as a part of the active hydrogen-containing compound (J), is a hydrazine derivative or tertiary amine that does not have active hydrogen, because it itself has no reactivity with an epoxy group. In order to be able to react with the epoxy group. The quaternary chlorinating agent reacts with an epoxy group in the presence of water as 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.
In addition, as a hydrazine derivative having no active hydrogen used for obtaining a quaternary chlorinating agent, for example, 3,6-dichloropyridazine and the like, and as a tertiary amine, for example, dimethylethanolamine, triethylamine, Examples include trimethylamine, triisopropylamine, and methyldiethanolamine.

  The hydrazine-modified organic resin (K) produced by the reaction between the organic resin (X) and the active hydrogen-containing compound (J) composed of a hydrazine derivative (I) partially or entirely having active hydrogen is an organic resin (X ) And the active hydrogen-containing compound (J) at 10 to 300 ° C., preferably 50 to 150 ° C., for about 1 to 8 hours. This reaction may be performed by adding an organic solvent. The kind of the organic solvent to be 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 Alcohols and ethers containing hydroxyl groups such as 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; ethyl acetate, butyl acetate, ethylene Esters such as glycol monobutyl ether acetate; Ene, can be exemplified aromatic hydrocarbons such as such as xylene, can be used one or two or more of these. Of these, ketone-based or ether-based solvents are particularly preferred from the standpoints of solubility with an epoxy resin and film-forming properties.

  The compounding ratio of the organic resin (X) and the active hydrogen-containing compound (J) composed of the hydrazine derivative (I) partly or entirely having active hydrogen is 100 parts by mass of the organic resin (X) in terms of solid content. On the other hand, it is desirable that the active hydrogen-containing compound (J) is 0.5 to 20 parts by mass, particularly preferably 1.0 to 10 parts by mass. Moreover, when organic resin (X) is epoxy group containing resin (X1), the compounding ratio of epoxy group containing resin (X1) and active hydrogen containing compound (J) is the active hydrogen containing compound (J). The ratio of the number of active hydrogen groups to the number of epoxy groups in the epoxy group-containing resin (X1) [number of active hydrogen groups / number of epoxy groups] is 0.01 to 10, more preferably 0.1 to 8, still more preferably 0.8. 2 to 4 is appropriate from the viewpoint of corrosion resistance and the like.

  The proportion of the hydrazine derivative (I) having active hydrogen in the active hydrogen-containing compound (J) is preferably 10 to 100 mol%, more preferably 30 to 100 mol%, and even more preferably 40 to 100 mol%. More preferred. If the ratio of the hydrazine derivative (I) having active hydrogen is less than 10 mol%, the second layer film (organic resin film) cannot be provided with a sufficient rust preventive function, and the resulting rust preventive effect is a film-forming organic resin. There is no significant difference from the case where the hydrazine derivative is simply mixed and used.

The anticorrosion mechanism of the second layer film (organic resin film) described above can be considered as follows.
That is, by providing the organic resin (X) with a hydrazine derivative (I) having active hydrogen, the hydrazine derivative is incorporated into the molecule of the organic resin (X),
(1) A dense second layer film is formed, and the second layer film exhibits the effect of blocking corrosion factors such as oxygen and chlorine ions.
(2) the hydrazine derivative (I) is stably and firmly bonded to the surface of the first layer film to form a passivating layer;

(3) Zinc and other metal ions eluted by the corrosion reaction are trapped by the free hydrazine derivative group in the second layer film, and a stable insoluble chelate compound layer is formed, so at the interface between the first layer film and the plating layer. The formation of the ion conductive layer is suppressed and the progress of corrosion is suppressed,
(4) The excessive elution of the first layer coating component is suppressed by the barrier effect of the second layer coating,
It is considered that the progress of corrosion is effectively suppressed by the action effects and the like, and excellent corrosion resistance is obtained.

  Further, when an epoxy group-containing resin (X1) is used as the organic resin (X), a dense barrier film is formed by a reaction between the epoxy group-containing resin (X1) and a curing agent (crosslinking agent), This barrier film exhibits an excellent permeation suppressing ability against corrosion factors such as oxygen. Moreover, since the outstanding bond strength with a 1st layer membrane | film | coat is obtained with the hydroxyl group in a molecule | numerator, especially outstanding corrosion resistance (barrier property) is obtained. Further, by using a pyrazole compound having active hydrogen or / and a triazole compound having active hydrogen as the hydrazine derivative (I) having active hydrogen, more excellent corrosion resistance (barrier properties) can be obtained.

  As a conventional technique, a method of using a composition in which a hydrazine derivative is mixed with a film-forming organic resin is known. However, simply by mixing a hydrazine derivative with a film-forming organic resin as in this conventional technique, the corrosion suppression is improved. Little effect is observed. This is because, in the prior art, hydrazine derivatives are not incorporated into the molecules of the film-forming organic resin. Hydrazine derivatives not incorporated in the molecule of the film-forming organic resin form a chelate compound with the metal in the first layer film, but the chelate compound is presumed not to be a dense barrier layer due to its low molecular weight. The On the other hand, by incorporating a hydrazine derivative into the molecule of the film-forming organic resin, a much superior corrosion inhibition effect can be obtained. Therefore, even when the film thickness of the second layer film, which is an organic resin film, is reduced in order to ensure the conductivity of the surface-treated steel sheet, the surface treatment liquid (β) containing the hydrazine-modified organic resin (K) is used. If it is the 2nd layer membrane | film | coat formed in this way, desired corrosion resistance can be provided to a surface-treated steel plate.

・ Anti-rust additive (L)
In this invention, a rust preventive additive (L) can be further contained in the surface treatment liquid (β) containing the organic resin (G).
In the present invention, when the second layer film is formed using the surface treatment liquid (β), it is as described above that a surface-treated steel sheet having extremely good corrosion resistance can be obtained. In order to further increase the corrosion resistance of the steel sheet, it is effective to add an antirust additive (L).
The type of the anticorrosive additive (L) is not particularly limited, and any of the anticorrosive additives such as a known anticorrosive agent can sufficiently exhibit the above effect, but is a self-repairable substance described below. It is particularly preferable to use one or more of (a) and (b).
(A) Ca ion exchange silica (b) Silicon oxide

The component (a), Ca ion-exchanged silica, is obtained by fixing calcium ions on the surface of the porous silica gel powder. This Ca ion exchange silica exhibits a rust prevention effect by releasing Ca ions in a corrosive environment to form a precipitated film.
Although arbitrary things can be used as Ca ion exchange silica, an average particle diameter is 6 micrometers or less, More preferably, it is 4 micrometers or less, For example, an average particle diameter of 2-4 micrometers can be used conveniently. . When the average particle diameter of the Ca ion exchange silica exceeds 6 μm, there is a concern that the corrosion resistance is lowered and the dispersion stability in the surface treatment liquid (β) is lowered.
The Ca concentration in the Ca ion exchange silica is preferably 1% by mass or more, and more preferably 2 to 8% by mass. If the Ca concentration is less than 1% by mass, the rust prevention effect due to Ca release may be insufficient. The surface area, pH, oil absorption, etc. of the Ca ion exchange silica are not particularly limited.

As Ca ion exchange silica as described above, SHIELDEX C303 (average particle size: 2.5 to 3.5 μm, Ca concentration: 3 mass%) manufactured by WRGrace & Co., SHIELDEX AC3 (average particle size: 2.3 to 3) .1μm, Ca concentration: 6% by mass), SHIELDEX
AC5 (average particle size: 3.8 to 5.2 μm, Ca concentration: 6% by mass) (all are trade names), SHIELDEX manufactured by Fuji Silysia Chemical Ltd. (average particle size: 3 μm, Ca concentration: 6) ~ 8 mass%), SHIELDEX
SY710 (average particle size: 2.2 to 2.5 μm, Ca concentration: 6.6 to 7.5 mass%) (all are trade names) can be used.

  The silicon oxide as the component (b) may be either colloidal silica or dry silica. When the water-based film-forming resin is used as a base, colloidal silica is, for example, manufactured by Nissan Chemical Industries, Ltd. Snowtex O, Snowtex N, Snowtex 20, Snowtex 30, Snowtex 40, Snowtex C, Snowtex S (all are trade names), Cataloid S, Cataloid SI-350, Catalloid SI-40, Cataloid SA, Cataloid SN (all are trade names) manufactured by Catalytic Kasei Kogyo Co., Ltd. Adelite AT-20 to 50, Adelite AT-20N, Adelite AT-300, Adelite AT-300S, Adelite AT20Q (all of which are trade names) manufactured by ADEKA can be used.

Further, when the solvent-based film-forming resin is used as a base, colloidal silica may be, for example, an organosilica sol MA-ST-MS, an organosilica sol IPA-ST, an organosilica sol EG-ST, an organosilica manufactured by Nissan Chemical Industries, Ltd. Silica sol IPA-ST-ZL, organosilica sol NPC-ST-30, organosilica sol DMAC-ST, organosilica sol MEK-ST-L, organosilica sol XBA-ST, organosilica sol MIBK-ST (all are trade names), catalyst OSCAL-1132, OSCAL-1232, OSCAL-1332, OSCAL-1432, OSCAL-1532, OSCAL-1632, OSCAL-1722 (all are trade names) manufactured by Kasei Kogyo Co., Ltd. can be used.
In particular, the organic solvent-dispersed silica sol is excellent in dispersibility and excellent in corrosion resistance than fumed silica (dry silica).

Moreover, as fumed silica (dry silica), for example, AEROSIL R812, AEROSIL R974, AEROSIL R202, AEROSIL R805, AEROSIL 130, AEROSIL 200, AEROSIL 300 (all are trade names) manufactured by Nippon Aerosil Co., Ltd. Can be used.
The fine particle silica as described above contributes to the formation of a dense and stable zinc corrosion product in a corrosive environment, and this corrosion product is densely formed on the plating surface, thereby suppressing the promotion of corrosion. It is thought that you can.
From the viewpoint of corrosion resistance, the particle diameter of the fine particle silica is preferably 5 to 50 nm, more preferably 5 to 20 nm, and even more preferably 5 to 15 nm.

Further, in addition to the above components (a) and (b), even when one or more of the following self-repairing substances are used as the anticorrosive additive (L), the same as the above components (a) and (b) An effect is obtained.
(C) Phosphate (d) Molybdate (e) One or more organic compounds selected from triazoles, thiols, thiadiazoles, thiazoles, thiurams The phosphate as the component (c) Includes all types of salts such as simple salts and double salts. Moreover, there is no limitation in the metal cation which comprises it, and any metal cation, such as 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 phosphate ions, and any of normal salt, dihydrogen salt, monohydrogen salt or phosphite may be used. In addition to orthophosphate, the normal salt may be polyphosphate. Includes all condensed phosphates such as salts.

Moreover, corrosion resistance can be further improved by adding a calcium compound together with the phosphate which is the said component (c). The calcium compound may be any of calcium oxide, calcium hydroxide, and calcium salt, and one or more of these can be used. In addition, there are no particular restrictions on the type of calcium salt. In addition to simple salts containing only calcium as a cation such as calcium silicate, calcium carbonate, and calcium phosphate, calcium and calcium such as calcium phosphate / zinc, calcium phosphate / magnesium, etc. Double salts containing other cations may be used.
The molybdate that is the component (d) is not limited in its skeleton and degree of condensation, and examples thereof include orthomolybdate, paramolybdate, and metamolybdate. Moreover, all salts, such as a single salt and a double salt, are included, and phosphoric acid molybdate etc. are mentioned as a double salt.

  Among the organic compounds of the component (e), triazoles include 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, etc., and thiols include 1,3,5-triazine-2,4,6-trithiol, 2-mercaptobenzimidazole, etc. The thiadiazoles include 5-amino-2-mercapto-1,3,4-thiadiazole, 2,5-dimercapto-1,3,4-thiadiazole, and the thiazoles include 2-N, N -Diethylthiobenzothiazole, 2-mercaptobenzothiazole, etc., and thiurams include tetraethylthiuram disulfi And so on.

  The total amount of the rust preventive additive (L) (the total amount of one or more self-repairing substances selected from the components (a) to (e)) is a surface treatment liquid (β ) Is preferably 1 to 100 parts by mass (solid content), more preferably 5 to 80 parts by mass (solid content), and further 10 to 50 parts by mass (solid content). More preferably). When the compounding quantity of a rust preventive additive (L) is less than 1 mass part or more than 100 mass parts, corrosion resistance may fall and it is unpreferable.

In the present invention, a particularly excellent anticorrosion performance (by incorporating an appropriate amount of one or more of the self-repairing substances (a) to (e) described above as the anticorrosive additive (L) in the second layer coating ( Self-healing effect). The anticorrosion mechanism obtained by blending the anticorrosive additive (L) in the second layer film is considered as follows.
When the component (a) of the anticorrosive additive (L) is blended in the second layer coating, if cations such as Na ions enter the second layer coating in a corrosive environment, the ion exchange action Ca ions on the silica surface are released, and OH ions are generated by the cathode reaction in a corrosive environment. When the pH in the vicinity of the plating interface rises along with this, Ca ions released from the Ca ion exchange silica precipitate as Ca (OH) ₂ near the plating interface, block defects as a dense and poorly soluble product, and corrode. Suppresses the reaction. In addition, it is conceivable that the eluted metal ions such as zinc are exchanged with Ca ions and fixed on the silica surface.
In addition, the component (b) contributes to the formation of a dense and stable corrosion product of a metal (such as zinc) in a corrosive environment, and the corrosion product is formed on the plating surface to cause corrosion. Suppresses the promotion of

The component (c) dissociates into phosphate ions by hydrolysis in a corrosive environment, and forms a protective film by causing a complex formation reaction with the eluted metal.
The component (d) exhibits self-repairing properties due to the passivating effect. That is, a dense oxide is formed on the surface of the plating film together with dissolved oxygen in a corrosive environment, and this inhibits the corrosion reaction by blocking the corrosion starting point.
The component (e) exhibits self-repairing properties due to the adsorption effect. That is, zinc and aluminum eluted by corrosion adsorb to the polar group containing nitrogen and sulfur contained in the component (e) to form an inactive film, which inhibits the corrosion reaction by blocking the corrosion starting point. .

  In the present invention, even when one or more selected from the above (a) to (e) are blended in a general organic film, a certain degree of anticorrosive effect can be obtained, but a specific organic polymer resin In the 2nd layer membrane | film | coat excellent in the barrier property containing (Organic resin (H) which has OH group and / or COOH group, or hydrazine modified | denatured organic resin (X)), from said (a)-(e) When one or more selected self-repairing substances are blended, it is considered that both effects (barrier property and self-repairing property) are combined and a very excellent anticorrosion effect is exhibited.

Furthermore, when a calcium compound is added in combination with the component (c) above, the calcium compound elutes preferentially over the plated metal in a corrosive environment, so that the dissolution of the plated metal is not triggered. It causes a complexing reaction with ions to form a dense and sparingly soluble protective film to suppress the corrosion reaction.
Further, in the surface treatment liquid (β), in addition to the above rust preventive additive components, as a corrosion inhibitor, one kind of other oxide fine particles, phosphomolybdate, organic phosphoric acid and its salt, organic inhibitor, etc. Or 2 or more types can be added.

・ Lubricant (M)
Moreover, in this invention, a lubricant (M) can be mix | blended with surface treatment liquid ((beta)) for the purpose of improving the workability of a film | membrane further as needed. Examples of the lubricant (M) that can be applied to the present invention include the following, and one or more of these can be used.
(1) Polyolefin wax, paraffin wax: For example, polyethylene wax (2) Synthetic paraffin, natural paraffin, micro wax, chlorinated hydrocarbon, etc. (3) Fluororesin fine particles: For example, polyfluoroethylene resin (polytetrafluoroethylene resin) Etc.), polyvinyl fluoride resin, polyvinylidene fluoride resin, etc.

  In addition to the above, fatty acid amide compounds (eg, stearic acid amide, palmitic acid amide, methylene bisstearoamide, ethylene bisstearoamide, oleic acid amide, esylic acid amide, alkylene bis fatty acid amide), metal Soaps (eg, calcium stearate, lead stearate, calcium laurate, calcium palmitate, etc.), metal sulfides (eg, molybdenum disulfide, tungsten disulfide, etc.), graphite, graphite fluoride, boron nitride, polyalkylene glycol, You may use 1 type, or 2 or more types, such as an alkali metal sulfate.

Among the above lubricants, polyethylene wax, fluororesin fine particles, particularly polytetrafluoroethylene resin fine particles are particularly suitable.
Examples of polyethylene wax include Clariant Japan Co., Ltd.'s Celidust 9615A, Celidust 3715, Celidust 3620, Celidust 3910 (all are trade names), Sanyo Chemical Co., Ltd. Sunwax 131-P, Sunwax 161 -P (all are trade names), Chemipearl W-100, Chemipearl W-200, Chemipearl W-500, Chemipearl W-800, Chemipearl W-950 (all are trade names) manufactured by Mitsui Chemicals, Inc. Etc. can be used.

As the fluororesin fine particles, tetrafluoroethylene fine particles are most preferable. For example, Lubron L-2, Lubron L-5 (all are trade names) manufactured by Daikin Industries, Ltd., MP1100 manufactured by Mitsui DuPont Co., Ltd. , MP1200 (all are trade names), Fullon Dispersion AD1, Fullon Dispersion AD2, Fullon L141J, Fullon L150J, Fullon L155J (all are trade names) manufactured by Asahi IC Fluoropolymers Co., Ltd. are suitable. It is.
Among these, a particularly excellent lubricating effect can be expected by the combined use of polyolefin wax and tetrafluoroethylene fine particles.
The blending amount of the lubricant (M) is preferably 1 to 80 parts by mass (solid content) with respect to 100 parts by mass (solid content) of the organic resin (G) in the surface treatment liquid (β). It is more preferable to set it to -40 mass parts (solid content). When the blending amount of the lubricant (M) is 1 part by mass or more, the lubrication effect is sufficient. On the other hand, when the blending amount is 80 parts by mass or less, there is no concern about a decrease in paintability.

Furthermore, in the present invention, for the purpose of forming the second layer film as a dense barrier film, a curing agent may be blended in the surface treatment liquid (β) and the second layer film may be cured by heating.
When the second layer film is formed as a dense barrier film, the curing method includes (1) a curing method using a urethanization reaction between isocyanate and a hydroxyl group in the base resin, and (2) an alkyl etherated amino resin and the base. Curing method using etherification reaction with hydroxyl group in resin (alkyl etherified amino resin is a part of methylol compound obtained by reacting formaldehyde with one or more selected from melamine, urea and benzoguanamine or (All obtained by reacting a monohydric alcohol having 1 to 5 carbon atoms) is suitable, but among these, it is particularly preferred that the main reaction is a urethanization reaction between an isocyanate and a hydroxyl group in the base resin. is there.

  In the present invention, an organic coloring pigment (for example, a condensed polycyclic organic pigment, a phthalocyanine organic pigment, etc.), a coloring dye (for example, an organic solvent-soluble azo dye, Water-soluble azo metal dyes), inorganic pigments (eg, titanium oxide), chelating agents (eg, thiols), conductive pigments (eg, metal powders such as zinc, aluminum, nickel, iron phosphide, antimony dope) Type tin oxide), a coupling agent (for example, a silane coupling agent, a titanium coupling agent, etc.), or one or more of melamine / cyanuric acid adducts can be added.

In the present invention, by using a surface treatment liquid (β) containing an organic resin (H) having an OH group and / or a COOH group or a hydrazine-modified organic resin (K), a surface treatment particularly excellent in adhesion and conductivity. The steel plate is obtained as described above. On the other hand, for example, when importance is attached to the workability of the surface-treated steel sheet, the organic resin (G) is a water-soluble urethane-modified acrylic resin and / or a water-dispersible urethane-modified acrylic resin (N) (hereinafter, for convenience of description "Aqueous urethane-modified acrylic resin (N)") and a specific proportion of this aqueous urethane-modified acrylic resin (N), curing agent (O), silicon oxide (b), and lubricant (M). It is recommended to use the surface treatment liquid (β) contained in
The water-based urethane-modified acrylic resin (N) may be either a water-soluble resin or a water-dispersible resin, or both may be used in combination. Further, the method for modifying the acrylic resin with urethane is not particularly limited. In the aqueous urethane-modified acrylic resin (N), the solid content ratio of the urethane component in the resin solid content is preferably 10 to 50% by mass, and more preferably 10 to 30% by mass.

The curing agent (O) is added in order to sufficiently crosslink the film, and excellent corrosion resistance and solvent resistance can be obtained by the crosslinking. There are no particular restrictions on the type of curing agent to be used, but there are epoxy groups and oxazolines that are not hydrophilic groups, such as amines having a hydrophilic group such as amino groups, hydroxyl groups, and carboxyl groups, polyhydric alcohols and polybasic acids. It is particularly preferable to use a compound having at least one functional group selected from a group, an isocyanate group, and an aziridinyl group.
The silicon oxide (b) is added to improve the corrosion resistance. There is no restriction | limiting in particular in the kind of silicon oxide (b), For example, 1 or more types, such as the colloidal silica mentioned above and a fumed silica, can be used. The particle size and type of silica are not particularly limited.

The lubricant (M) improves the scratch resistance as a lubricating component. There are no particular restrictions on the type of lubricant (M). For example, carnauba wax, rice wax, lanolin wax, montan wax, paraffin wax, microcrystalline wax, fatty acid ester wax, fatty acid amide wax, or a partially saponified product thereof, polyethylene Wax, polyolefin wax, chlorinated hydrocarbon, fluorinated hydrocarbon, ethylene acrylic copolymer wax, and the like can be used, and one or more of these can be used.
The average particle size of the lubricant (M) is preferably 0.05 to 3.0 μm. The melting point of the lubricant (M) is preferably 50 to 160 ° C. As the shape of the lubricant particles, a spherical shape is more preferable in order to obtain a high workability.

Total solid content mass of water-based urethane-modified acrylic resin (N) + curing agent (O) + silicon oxide (b) + lubricant (M) (hereinafter, “(N) + (O) + (b) + (M)” The solid content ratio of the water-based urethane-modified acrylic resin (N) and the curing agent (O) is preferably 50 to 95% by mass, and preferably 55 to 75% by mass. More preferred.
It is preferable to mix | blend a hardening | curing agent (O) so that solid content mass ratio with aqueous | water-based urethane modified acrylic resin (N) may be (N) / (O) = 4-49.
It is preferable that the compounding quantity of a silicon oxide (b) shall be 3-40 mass% in the solid content ratio with respect to (N) + (O) + (b) + (M).
The blending amount of the lubricant (M) is preferably 2 to 20% by mass, and preferably 5 to 15% by mass in terms of the solid content ratio with respect to (N) + (O) + (b) + (M). More preferred.

The surface treatment liquid (β) for the second layer film used in the present invention improves the surfactant, thickener, and conductivity called a wettability improver for forming a uniform film on the coated surface. A conductive material for the purpose, a color pigment for improving the designability, a solvent for improving the film forming property, and the like may be added as necessary.
The film thickness (dry film thickness) of the second layer film formed by the surface treatment liquid (β) is 0.05 μm or more and less than 1.5 μm, preferably 0.1 to 1.0 μm. If the film thickness is 0.05 μm or more, the corrosion resistance and fingerprint resistance are sufficient, while if it is less than 1.5 μm, there is no concern of a decrease in conductivity.
In addition, when the hydrazine-modified organic resin (K) is used as the organic resin (G) for the second layer film, a uniform and excellent corrosion resistance film can be obtained even if the film thickness is thin. It is advantageous for improving the conductivity without incurring a decrease.

  In the surface-treated steel sheet of the present invention, the total film thickness (dry film thickness) per side of the first layer film and the second layer film is 0.1 to 2.0 μm, preferably 0.1 to 1.0 μm. If the total film thickness is less than 0.1 μm, the corrosion resistance is insufficient, while if it exceeds 2.0 μm, the conductivity is lowered. In order to achieve both corrosion resistance and conductivity, it is preferable that the thickness of the first layer coating is 0.05 μm or more and the thickness of the second layer coating is 1.0 μm or less.

The present invention includes a surface-treated steel sheet having a coating as described above on both sides or one side. Therefore, examples of the form of the surface-treated steel sheet according to the present invention include the following.
(1) One side: plating layer-first layer coating-second layer coating, one side: plating layer (2) One side: plating layer-first layer coating-second layer coating, one side: plating layer-known phosphate Treatment film, etc. (3) Both sides: Plating layer-First layer coating-Second layer coating (4) Single side: Plating layer-First layer coating-Second layer coating, Single side: Plating layer-First layer coating (5) One side: plating layer-first layer coating-second layer coating, one side: plating layer-second layer coating

  The surface-treated steel sheet of the present invention as described above has excellent performance such as corrosion resistance and adhesion, and excellent conductivity even under severe conditions where the steel sheet is contacted at a low pressure without particularly reducing the corrosion resistance. Have sex. Such a surface-treated steel sheet of the present invention can be applied to various uses, and is suitably used for materials used in various fields such as architecture, electricity, and automobiles.

Next, the manufacturing method of the surface treatment steel plate of this invention is demonstrated.
In order to produce the surface-treated steel sheet of the present invention, the surface treatment liquid (α) having the above-described composition is applied to the surface of the zinc-based plated steel sheet or the aluminum-based plated steel sheet so as to have a predetermined film thickness, and is dried. Then, the first layer film is formed, and the surface treatment liquid (β) having the above-described composition is applied to the surface of the first layer film so as to have a predetermined film thickness, and dried to form the second layer film. Let it form.
As a method for applying the surface treatment liquid (α) for the first layer film to the plated steel sheet surface, any of an application method, an immersion method, and a spray method may be used. As a coating treatment method, any method such as a roll coater (3-roll method, 2-roll method, etc.), a squeeze coater, or a die coater may be used. Further, after the coating treatment or dipping treatment using a squeeze coater or the like and the spraying treatment, the coating amount can be adjusted, the appearance can be made uniform, and the film thickness can be made uniform by an air knife method or a roll drawing method.

  After the surface treatment liquid (α) is applied, it is usually heated and dried without washing with water. As the heating and drying means, a dryer, a hot air furnace, a high frequency induction heating furnace, an infrared furnace or the like can be used. It is desirable that the heat drying is carried out in the range of 30 to 200 ° C., preferably 40 to 140 ° C., at the ultimate plate temperature. If the heating and drying temperature is 30 ° C. or higher, no moisture remains in the first layer coating, and if the heating temperature is 200 ° C. or lower, the occurrence of defects in the first layer coating is suppressed. There is no problem such as a decrease in corrosion resistance.

The method for applying the surface treatment liquid (β) for the second layer film may be any of an application method, a dipping method, and a spray method, and the specific method is the same as that of the surface treatment liquid (α). After application of the treatment liquid (β), heating and drying are usually performed without washing with water, but washing with water may be performed after application of the surface treatment liquid (β). As the heating and drying means, a dryer, a hot air furnace, a high frequency induction heating furnace, an infrared furnace or the like can be used. Heat drying is preferably performed in the range of 50 to 350 ° C., preferably 80 to 250 ° C., at the ultimate plate temperature. If the heating and drying temperature is 50 ° C. or higher, no solvent remains in the second layer coating, and if the heating temperature is 350 ° C. or lower, the generation of cracks in the second layer coating is suppressed. There is no problem such as a decrease in corrosion resistance. The heating time is appropriately selected according to the type of plated steel sheet used. From the viewpoint of productivity and the like, about 0.1 to 60 seconds is preferable, and about 1 to 30 seconds is more preferable.

<Preparation of surface treatment liquid for first layer coating>
Treatment agents P1 to P63 (surface treatment liquids) shown in Tables 2 and 3 were prepared by appropriately blending the titanium-containing aqueous liquid (A) and the components (B) to (F). The titanium-containing aqueous liquid (A) and components (B) to (F) used for the treating agent are shown below.
[Production of titanium-containing aqueous liquid (A)]
Production Example 1 (Titanium-containing aqueous liquid T1)
Ammonia water (1: 9 = ammonia: water mass ratio) was added dropwise to a solution in which 5 cc of a titanium tetrachloride 60 mass% solution was made 500 cc with distilled water to precipitate a low condensation product of titanium hydroxide. After washing with distilled water, 10 cc of a 30% by mass hydrogen peroxide solution was added and stirred to obtain a yellow translucent viscous titanium-containing aqueous liquid T1 containing titanium.

Production Example 2 (Titanium-containing aqueous liquid T2)
A mixture of 10 parts by mass of tetraiso-propoxytitanium and 10 parts by mass of iso-propanol was dropped into a mixture of 30 parts by mass of 10 parts by mass of hydrogen peroxide and 100 parts by mass of deionized water with stirring at 20 ° C. over 1 hour. did. Thereafter, aging was carried out at 25 ° C. for 2 hours to obtain a yellow transparent, slightly viscous titanium-containing aqueous liquid T2.
Production Example 3 (Titanium-containing aqueous liquid T3)
A titanium-containing aqueous liquid T3 was obtained under the same production conditions as in Production Example 2 except that tetra-n-butoxy titanium was used instead of tetraiso-propoxy titanium used in Production Example 2.

Production Example 4 (Titanium-containing aqueous liquid T4)
In the same production conditions as in Production Example 2, except that a tetramer of tetraiso-propoxytitanium (low condensation product of tetraiso-propoxytitanium) was used instead of tetraiso-propoxytitanium used in Production Example 2, titanium was used. A contained aqueous liquid T4 was obtained.
Production Example 5 (Titanium-containing aqueous liquid T5)
A titanium-containing aqueous liquid was produced under the same production conditions as in Production Example 2, except that hydrogen peroxide was used in 3 times the amount of Production Example 2, dropped at 50 ° C over 1 hour, and further aged at 60 ° C for 3 hours. T5 was obtained.

Production Example 6 (Titanium-containing aqueous liquid T6)
The titanium-containing aqueous liquid T3 produced in Production Example 3 was further heat-treated at 95 ° C. for 6 hours to obtain a white yellow translucent titanium-containing aqueous liquid T6.
Production Example 7 (Titanium-containing aqueous liquid T7)
A mixture of 10 parts by mass of tetraiso-propoxytitanium and 10 parts by mass of iso-propanol, 5 parts by mass (solid content) of “TKS-203” (trade name, manufactured by Teika Co., Ltd.), 30% by mass hydrogen peroxide solution The mixture was added dropwise to a mixture of 10 parts by mass and 100 parts by mass of deionized water with stirring at 10 ° C. over 1 hour. Thereafter, the mixture was aged at 10 ° C. for 24 hours to obtain a yellow transparent, slightly viscous titanium-containing aqueous liquid T7.

[Organic Phosphate Compound (B)]
B1: 1-hydroxymethane-1,1-diphosphonic acid B2: 1-hydroxyethane-1,1-diphosphonic acid B3: 1-hydroxypropane-1,1-diphosphonic acid B4: 2-hydroxyphosphonoacetic acid B5: 2 -Phosphonobutane-1,2,4-tricarboxylic acid B6: Potassium 2-hydroxyphosphonoacetate [vanadic acid compound (C)]
C1: ammonium metavanadate C2: sodium metavanadate C3: potassium metavanadate [zirconium carbonate compound (D)]
D1: Ammonium zirconium carbonate D2: Sodium zirconium carbonate D3: Lithium zirconium carbonate

[Silane coupling agent (E)]
E1: γ-glycidoxypropyltrimethoxysilane E2: N-β (aminoethyl) γ-aminopropyltrimethoxysilane [water-soluble or water-dispersible organic resin (F)]
F1: Epiretz 6943 (trade name, manufactured by Japan Epoxy Resin, nonionic water-based epoxy resin)
F2: Epiletz 3520WY55 (trade name, manufactured by Japan Epoxy Resin, Nonionic water-based epoxy resin)
F3: Epiretz 3540WY55 (trade name, manufactured by Japan Epoxy Resin, Nonionic water-based epoxy resin)
F4: Adeka Resin EM-0718 (trade name, manufactured by Asahi Denka Kogyo Co., Ltd., cationic aqueous epoxy resin)
F5: Superflex E-2500 (trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., water-based polyurethane resin)
F6: Bironal MD-1100 (trade name, manufactured by Toyobo Co., Ltd., water-based polyester resin)

<Preparation of surface treatment liquid for second layer coating>
Treatment agents Q1 to Q38 (surface treatment solutions) shown in Table 4 were prepared by appropriately blending an organic resin (G) with a rust inhibitor and a lubricant. The organic resin (G), rust preventive additive and lubricant used for the treating agent are shown below.
[Organic resin: Organic resin having no OH group and / or COOH group]
G1: Polyolefin resin (manufactured by Toho Chemical Co., Ltd., trade name: HYTEC
S-3121)
G2: Fluororesin (Asahi Glass Co., Ltd., trade name: Lumiflon LF552)
[Organic resin: Organic resin (H) having OH group and / or COOH group]
G3: Epoxy resin (made by Japan Epoxy Resin Co., Ltd., trade name: jER1009)
G4: Urethane resin (Daiichi Kogyo Seiyaku Co., Ltd., trade name: Superflex E-2000)
G5: Alkyd resin (manufactured by Hitachi Chemical Co., Ltd., trade name: Phthalkid W2343)

[Organic resin: hydrazine-modified organic resin (K)]
G6: [Synthesis Example 1]
EP828 (epoxy resin, manufactured by Yuka Shell Epoxy Co., Ltd., epoxy equivalent 187): 1870 parts by mass, bisphenol A91: 2 parts by mass, tetraethylammonium bromide: 2 parts by mass, methyl isobutyl ketone: 300 parts by mass The mixture was heated to 140 ° C. and reacted for 4 hours to obtain an epoxy resin having an epoxy equivalent of 1391 and a solid content of 90% by mass. To this, ethylene glycol monobutyl ether: 1500 parts by mass was cooled to 100 ° C., 96 parts by mass of 3,5-dimethylpyrazole (molecular weight 96) and 129 parts by mass of dibutylamine (molecular weight 129) were added, and epoxy was added. After reacting for 6 hours until the group disappeared, 205 parts by mass of methyl isobutyl ketone was added while cooling to obtain a pyrazole-modified epoxy resin having a solid content of 60% by mass. This is designated as organic resin (G6). This organic resin (G6) is a reaction product of the organic resin (X) and the active hydrogen-containing compound (J) containing 50 mol% of the hydrazine derivative (I) having active hydrogen.

G7: [Synthesis Example 2]
EP1007 (epoxy resin, manufactured by Japan Epoxy Resin Co., Ltd., epoxy equivalent 2000): 4000 parts by mass and ethylene glycol monobutyl ether: 2239 parts by mass were charged into a four-necked flask and heated up to 120 ° C to complete in 1 hour. The epoxy resin was dissolved. This was cooled to 100 ° C., 168 parts by mass of 3-amino-1,2,4-triazole (molecular weight 84) was added and reacted for 6 hours until the epoxy group disappeared, and then methyl isobutyl ketone 540 while cooling. By adding part by mass, a triazole-modified epoxy resin having a solid content of 60% by mass was obtained. This is designated as organic resin (G7). This organic resin (G7) is a reaction product of the organic resin (X) and the active hydrogen-containing compound (J) containing 100 mol% of the hydrazine derivative (I) having active hydrogen.

[Ca ion exchange silica (a)]
a1: Ca ion exchange silica (manufactured by WRGrace & Co., trade name: SHIELDEX C303)
[Silicon oxide (b)]
b1: Fumed silica (manufactured by Nippon Aerosil Co., Ltd., trade name: AEROSIL 200)
b2: Organosilica sol (manufactured by Nissan Chemical Industries, Ltd., trade name: Organosilica sol MA-ST-MS)
b3: Colloidal silica (manufactured by Nissan Chemical Industries, Ltd., trade name: Snowtex 30)
[Phosphate (c)]
c1: Zinc phosphate [molybdate (d)]
d1: Aluminum molybdate [lubricant (M)]
M1: Polyethylene wax (manufactured by Clariant Japan Co., Ltd., trade name: Celidust 3620)

<Manufacture and performance evaluation of surface-treated steel sheets>
Using the various plated steel sheets shown in Table 1 as the processing original plate, the surface of the plated steel sheet was subjected to alkaline degreasing treatment, washed with water and dried, and then applied with a treatment agent (surface treatment liquid) for the first layer film shown in Table 2 and Table 3. Then, it was dried at various temperatures, and then a treatment agent (surface treatment liquid) for the second layer film shown in Table 4 was applied and dried at various temperatures to obtain surface-treated steel sheets of invention examples and comparative examples. In addition, the film thickness of the film was adjusted by the solid content (heating residue) of the surface treatment liquid.
The results of evaluating the quality performance (corrosion resistance, paint adhesion, conductivity) of the obtained surface-treated steel sheet are shown in Tables 5 to 11 together with the production conditions. In addition, the measurement and evaluation method of each quality performance is as follows.

(1) White rust resistance A test piece having a size of 70 × 150 mm was cut out from each test plate, and the back and end portions were sealed with vinyl tape. A salt spray test (SST) based on JIS-Z-2371-2000 was performed on this test piece, and the white rust generation area ratio after 192 hours of SST was visually confirmed and evaluated according to the following evaluation criteria. .
◎: White rust occurrence area ratio less than 5% ○: White rust occurrence area ratio 5% or more, less than 20% ○-: White rust occurrence area ratio 20% or more, less than 40% △: White rust occurrence area ratio 40% or more Less than 70% x: White rust generation area ratio 70% or more

(2) White rust resistance after alkali degreasing A test piece having a size of 70 × 150 mm was cut out from each test plate, and an alkali treatment solution “CLN-364S” manufactured by Nihon Parker Rising Co., Ltd. (60 ° C., spray 2 minutes) After degreasing with alkali, the back and end portions were sealed with vinyl tape. A salt spray test (SST) based on JIS-Z-2371-2000 was carried out on this test piece, the white rust generation area ratio after 120 hours of SST was confirmed visually, and evaluated according to the following evaluation criteria. .
◎: White rust occurrence area ratio less than 5% ○: White rust occurrence area ratio 5% or more, less than 20% ○-: White rust occurrence area ratio 20% or more, less than 40% △: White rust occurrence area ratio 40% or more Less than 70% x: White rust generation area ratio 70% or more

(3) Paint adhesion (top coatability)
A test piece having a size of 70 × 150 mm was cut out from each test plate, and a commercially available melamine alkyd paint was applied to the surface of the test piece so as to have a coating thickness of 30 μm, followed by baking at 140 ° C. for 30 minutes. Next, after immersing in boiling water for 2 hours, the test piece was cut into the base steel with an NT cutter to form 100 1 mm square grids. Next, after extruding 5 mm with an Erichsen extruder so that the incised part is on the outside (front) side, the adhesive tape is applied to the part (the incised part) and a peeling test is performed. Based on the area ratio from which peeling occurred, the following evaluation criteria were used. The Eriksen extrusion conditions were JIS-Z-2247-2006 (Erichsen value symbol: IE), punch diameter: 20 mm, die diameter: 27 mm, and drawing width: 27 mm.
A: Peeling area ratio less than 5% and no peeling B: Peeling area ratio of 5% or more and less than 10% Δ: Peeling area ratio of 10% or more and less than 20% ×: Peeling area ratio of 20% or more

(4) Conductivity The test plate was evaluated by measuring the surface resistance value using “Loresta GP, ESP terminal” manufactured by Mitsubishi Chemical Analytech Co., Ltd. The surface resistance value was measured by increasing the load applied to the terminal at a pitch of 50 g, and evaluated according to the following evaluation criteria with the minimum load that could achieve 10 ⁻⁴ Ω or less.
◎: Average load of 10 point measurement is less than 500 g ○: Average load of 10 point measurement is 500 g or more and less than 650 g ○ −: Average load of 10 point measurement is 650 g or more and less than 800 g Δ: Average load of 10 point measurement is 800 g Above, less than 950 g x: Average load of 10-point measurement is 950 g or more

  According to Tables 5 to 11, the present invention examples are excellent in white rust resistance and white rust resistance (corrosion resistance) after alkali degreasing, paint adhesion, and conductivity. On the other hand, in the comparative example, any one or more of white rust resistance, white rust resistance after alkali degreasing, paint adhesion, and conductivity is inferior to the examples of the present invention.

In Tables 2 and 3, * 1 to * 8 indicate the following contents.
* 1 Titanium-containing aqueous liquids T1 to T7 described in the main text of the specification
* 2 Organophosphate compounds B1 to B6 described in the specification text
* 3 Vanadic acid compounds C1 to C3 described in the specification text
* 4 Zirconium carbonate compounds D1 to D3 described in the specification text
* 5 Silane coupling agents E1, E2 described in the main text of the specification
* 6 Water-soluble or water-dispersible organic resins F1 to F6 described in the main text of the specification
* 7 Mass of solids in 1 liter of surface treatment solution (g)
* 8 Mass% of solid content in the surface treatment solution

In Table 4, * 1 to * 4 indicate the following contents.
* 1 Organic resins G1 to G7 described in the specification text
* 2 Rust preventive additives a1, b1 to b3, c1, d1 described in the main text of the specification
* 3 Lubricant M1 in the description text
* 4 Mass part of solid content
* 5 Mixing ratio (mass ratio) of two or more rust preventive additives

In Tables 5 to 11, * 1 to * 3 indicate the following contents.
* 1 Plated steel plates X1 to X9 listed in Table 1
* 2 Treatment agents P1 to P63 listed in Tables 2 and 3
* 3 Treatment agents Q1 to Q38 listed in Table 4

Claims (12)

At least one titanium selected from a hydrolyzable titanium compound, a hydrolyzable titanium compound low-condensate, titanium hydroxide, and a titanium hydroxide low-condensate on the surface of a zinc-based plated steel sheet or an aluminum-based plated steel sheet 1 to 400 parts by mass of the organic phosphoric acid compound (B) and vanadate compound (C) with respect to 100 parts by mass of the solid content of the titanium-containing aqueous liquid (A) obtained by mixing the compound with hydrogen peroxide. 1 to 500 parts by mass, zirconium carbonate compound (D) is contained in excess of 400 parts by mass and 1000 parts by mass or less, and silane coupling agent (E) is contained in a ratio of 5 to 50 parts by mass in the total solid content of the surface treatment liquid. % containing a surface treatment solution (alpha) (excluding the surface treatment solution containing zirconium fluoride compound) was applied to have a first layer coating formed by drying, to its upper layer, first It has a second layer film formed by applying a surface treatment liquid (β) containing an organic resin (G) to the surface of the film and drying it, and is a total film of the first layer film and the second layer film A surface-treated steel sheet having a thickness of 0.1 to 2.0 μm per side.   The surface treatment liquid (α) further contains a water-soluble organic resin and / or a water-dispersible organic resin (F) in an amount of 10 to 2000 parts by mass with respect to 100 parts by mass of the solid content of the titanium-containing aqueous liquid (A). The surface-treated steel sheet according to claim 1.   The surface-treated steel sheet according to claim 1 or 2, wherein the organophosphate compound (B) contained in the surface treatment liquid (α) is 1-hydroxyethane-1,1-diphosphonic acid.   The surface-treated steel sheet according to any one of claims 1 to 3, wherein the vanadic acid compound (C) contained in the surface treatment liquid (α) is ammonium metavanadate.   The surface-treated steel sheet according to any one of claims 1 to 4, wherein the zirconium carbonate compound (D) contained in the surface treatment liquid (α) is ammonium zirconium carbonate.   The surface-treated steel sheet according to any one of claims 1 to 5, wherein the silane coupling agent (E) contained in the surface treatment liquid (α) has a glycidyl group.   The water-soluble organic resin and / or water-dispersible organic resin (F) contained in the surface treatment liquid (α) is a water-soluble urethane resin or / and a water-dispersible urethane resin. The surface-treated steel sheet according to any one of the above.   At least a part of the organic resin (G) contained in the surface treatment liquid (β) is an organic resin (H) having an OH group and / or a COOH group. The surface-treated steel sheet according to item.   The surface-treated steel sheet according to any one of claims 1 to 7, wherein at least a part of the organic resin (G) contained in the surface treatment liquid (β) is a hydrazine-modified organic resin (K). .   The surface-treated steel sheet according to any one of claims 1 to 9, wherein the surface treatment liquid (β) further contains a rust preventive additive (L). The rust preventive additive (L) is the following (a) and / or (b), and the content of the rust preventive additive (L) is a solid content ratio, and the organic resin 100 in the surface treatment liquid (β) It is 1-100 mass parts with respect to a mass part, The surface-treated steel plate of Claim 10 characterized by the above-mentioned.
(A) Ca ion exchange silica (b) Silicon oxide   The surface-treated steel sheet according to any one of claims 1 to 11, wherein the surface treatment liquid (β) further contains a lubricant (M).