JP2008274419A - Surface treated steel sheet having excellent corrosion resistance, electrodeposition coating adhesion and weldability - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a chromium-free surface treated steel sheet capable of obtaining excellent corrosion resistance, electrodeposition coating adhesion and weldability. <P>SOLUTION: A surface treatment film by a surface treatment composition obtained by compositely adding an organic phosphoric acid compound, a nonionic aqueous bisphenol A type epoxy resin, a vanadate compound, a zirconium fluoride compound and a zirconium carbonate compound in prescribed ratios to a titanium-based aqueous solution obtained by mixing a specified titanium compound with a hydrogen peroxide solution is formed on the surface of a galvanized steel sheet or an aluminum-based plated steel sheet, and preferably, an organic film is formed on the upper layer thereof. The steel sheet has excellent corrosion resistance and weldability, and further has particularly excellent electrodeposition coating adhesion by the addition of the nonionic aqueous bisphenol A type epoxy resin in the surface treatment film. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a surface-treated steel sheet that is optimal for applications such as automobiles, home appliances, and building materials, and particularly relates to an environment-friendly surface-treated steel sheet that does not contain any chromium in the film.

  Conventionally, steel sheets for home appliances, steel sheets for building materials, and steel sheets for automobiles have 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-plated steel sheets. Steel plates subjected to chromate treatment with a treatment liquid containing chromic acid or a salt thereof as a main component are widely used. This chromate treatment is an economical treatment method that is excellent in corrosion resistance and can be performed relatively easily.

  Chromate treatment uses hexavalent chromium, a pollution-controlling substance, but this hexavalent chromium is treated in a closed system in the treatment process, completely reduced and recovered, and is not released to nature. Since the elution of chromium from the chromate film can be made almost zero by the sealing action of the organic film formed on the body, the human body and the environment are not substantially contaminated by hexavalent chromium. However, in view of recent global environmental problems, there is a growing trend to voluntarily reduce the use of heavy metals including hexavalent chromium. In addition, in order to prevent the environment from being polluted when the shredder dust of discarded products is dumped, there has been a movement to minimize the content of heavy metals in the products as much as possible.

For this reason, in order to prevent the occurrence of white rust in galvanized steel sheets, many treatment techniques that do not rely on chromate treatment, so-called chromium-free techniques, have been proposed. For example, there is a method of forming a thin film by a method such as immersion, coating, or electrolytic treatment using an inorganic compound, an organic compound, an organic polymer material, or a solution combining these. As one of them, Patent Document 1 discloses a method of forming a film with a surface treatment liquid comprising a titanium compound, an organic phosphate compound, a water-soluble resin, a vanadate and a zirconium salt.
JP 2006-9121 A

The method of Patent Document 1 is a process in which a mixed liquid in which a specific metal salt is combined with a specific titanium-based aqueous liquid is dried on the surface of the steel sheet, forming a complex salt with the metal ions contained therein, and a titanium oxide-based dense film component. As a result of precipitation, a film having a good corrosion-inhibiting ability is formed. Further, the cohesive force of the film can be improved and the adhesion can be enhanced by the aqueous resin to be added. However, the disclosed water-based resin has a problem in that the adhesion decreases under severe conditions such as immersion in warm water after electrodeposition coating, and the electrodeposition coating peels off. The following points can be considered as the cause.
(I) Acrylic and urethane water-based resins have insufficient adhesion of the resin itself, and the electrodeposition coating tends to peel off under severe conditions such as immersion in warm water.
(Ii) Since the epoxy-based aqueous resin uses a cationized epoxy resin, the alkali at the interface generated during electrodeposition coating reacts with the cation resin, and the adhesion tends to decrease.

  Therefore, an object of the present invention is a surface-treated steel sheet that solves such problems of the prior art and does not contain chromium at all in the film, and that provides excellent corrosion resistance, electrodeposition coating adhesion and weldability. It is to provide a steel sheet.

As a result of intensive studies by the present inventors in order to solve the above-mentioned problems, a bisphenol A type epoxy resin having good adhesion is used as an aqueous resin, and a nonionic system is used instead of a cationic system as a means for making it aqueous. It has been found that electrodeposition coating adhesion can be improved, and particularly excellent electrodeposition coating adhesion can be obtained by setting the molecular weight within a certain range.
The present invention has been made on the basis of such knowledge 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), nonionic aqueous bisphenol with respect to 100 parts by mass of the solid content of a titanium-containing aqueous liquid (A) obtained by mixing a seed titanium compound with hydrogen peroxide water 10 to 2000 parts by mass of A-type epoxy resin (C) in solid content, 1 to 400 parts by mass of vanadic acid compound (D), 1 to 400 parts by mass of zirconium fluoride compound (E), zirconium carbonate compound (F) It is characterized by having a surface treatment film with a film thickness of 0.01 to 1.0 μm formed by applying and drying a surface treatment composition containing 1 to 400 parts by mass of Corrosion, excellent surface-treated steel sheet to electrodeposition coating adhesion and weldability.

[2] In the surface-treated steel sheet according to [1] above, the nonionic aqueous bisphenol A type epoxy resin (C) has a number average molecular weight of 1000 to 8000, and has excellent corrosion resistance, electrodeposition coating adhesion and weldability. Excellent surface-treated steel sheet.
[3] The surface-treated steel sheet according to [1] or [2], wherein the nonionic aqueous bisphenol A type epoxy resin (C) is an aqueous bisphenol A type epoxy resin having a polyoxyalkylene chain, Surface-treated steel sheet with excellent electrodeposition coating adhesion and weldability.
[4] The surface-treated steel sheet according to any one of [1] to [3] above, further having an organic film having a film thickness of 0.1 to 5.0 μm on an upper layer of the surface-treated film. A surface-treated steel sheet with excellent corrosion resistance, electrodeposition coating adhesion and weldability.
[5] In the surface-treated steel sheet according to [4], the main component of the resin composition of the organic coating is a coating-forming organic resin (G) and a hydrazine derivative (I) in which some or all of the compounds have active hydrogen. A surface-treated steel sheet excellent in corrosion resistance, electrodeposition coating adhesion and weldability, characterized by being a reaction product with an active hydrogen-containing compound (H).

[6] In the surface-treated steel sheet according to [4] or [5], the organic coating contains 0.1 to 50 parts by mass of the non-chromium rust preventive additive with respect to 100 parts by mass of the solid content of the resin composition. A surface-treated steel sheet having excellent corrosion resistance, electrodeposition coating adhesion and weldability.
[7] The surface-treated steel sheet of [6], wherein the non-chromium rust preventive additive is at least one selected from the following (a) to (e): corrosion resistance, electrodeposition coating adhesion Surface-treated steel sheet with excellent weldability and weldability.
(A) silicon oxide (b) calcium compound (c) poorly soluble phosphate compound (d) molybdate compound (e) one or more selected from triazoles, thiols, thiadiazoles, thiazoles, thiurams In the surface-treated steel sheet according to any one of the above [4] to [7], the organic coating contains 1 solid lubricant with respect to 100 parts by mass of the solid content of the resin composition. A surface-treated steel sheet excellent in corrosion resistance, electrodeposition coating adhesion and weldability, characterized by containing ~ 30 parts by mass.

[9] 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), nonionic aqueous bisphenol with respect to 100 parts by mass of the solid content of a titanium-containing aqueous liquid (A) obtained by mixing a seed titanium compound with hydrogen peroxide water 10 to 2000 parts by mass of A-type epoxy resin (C) in solid content, 1 to 400 parts by mass of vanadic acid compound (D), 1 to 400 parts by mass of zirconium fluoride compound (E), zirconium carbonate compound (F) The surface treatment composition containing 1 to 400 parts by mass of the material is applied and dried at a final plate temperature of 30 to 200 ° C. to form a surface treatment film having a film thickness of 0.01 to 1.0 μm. Corrosion resistance characterized by Rukoto, electrodeposition coating adhesion and producing method of the excellent surface treatment steel sheet weldability.

[10] At least one selected from hydrolyzable titanium compounds, hydrolyzable titanium compound low condensates, titanium hydroxide, and titanium hydroxide low condensates 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), nonionic aqueous bisphenol with respect to 100 parts by mass of the solid content of a titanium-containing aqueous liquid (A) obtained by mixing a seed titanium compound with hydrogen peroxide water 10 to 2000 parts by mass of A-type epoxy resin (C) in solid content, 1 to 400 parts by mass of vanadic acid compound (D), 1 to 400 parts by mass of zirconium fluoride compound (E), zirconium carbonate compound (F) The surface treatment composition containing 1 to 400 parts by mass of the material is applied and dried at a final plate temperature of 30 to 200 ° C. to form a surface treatment film having a film thickness of 0.01 to 1.0 μm. Then, a coating composition is applied to the upper layer and dried at an ultimate plate temperature of 30 to 300 ° C., thereby forming an organic film having a film thickness of 0.1 to 5.0 μm. A method for producing a surface-treated steel sheet having excellent electrodeposition coating adhesion and weldability.

  The surface-treated steel sheet of the present invention has excellent corrosion resistance despite having no chromium in the coating, and has excellent electrodeposition coating adhesion and weldability.

The details of the present invention and the reasons for limitation will be described below.
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% Al alloy-plated steel sheet, Zn-55% Al alloy-plated steel sheet), Zn-Mg alloy-plated steel sheet, Zn-Al-Mg alloy-plated steel sheet (for example, Zn-6% Al-3) % Mg alloy-plated steel sheet, Zn-11% Al-3% Mg alloy-plated steel sheet), and metal oxides and polymers in the plating film of these plated steel sheets Etc. can be used as dispersed zinc composite-plated steel sheet (for example, Zn-SiO ₂ dispersion plating steel plate).

In addition, among the above-described plating, a multi-layer plated steel sheet in which two or more layers of the same type or different types are plated 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 among an electrolytic method (electrolysis in an aqueous solution or electrolysis in a nonaqueous solvent), a melting method, and a gas phase method can be adopted.
Furthermore, in order to prevent blackening of the plating, about 1 to 2000 ppm of one or more trace elements of Ni, Co, and Fe are deposited in the plating film, or one of Ni, Co, and Fe is deposited on the surface of the plating film. You may make it precipitate these elements by performing the surface adjustment process by the alkaline aqueous solution or acidic aqueous solution containing the above.

Next, the surface treatment film formed as the first layer film and the surface treatment composition for forming this film on the surface of the zinc-based plated steel sheet or the aluminum-based plated steel sheet will be described.
In the surface-treated steel sheet of the present invention, the 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), an organic phosphate compound (B), and a nonionic aqueous bisphenol. By applying and drying a surface treatment composition (X) containing A-type epoxy resin (C), vanadic acid compound (D), zirconium fluoride compound (E) and zirconium carbonate compound (F) as essential components Is formed. This surface treatment film does not contain chromium (except for chromium as an inevitable impurity).
The reason why excellent quality performance is obtained by forming such a surface-treated film is not necessarily clear, but a mixed solution in which a specific metal salt is combined with a specific titanium-based aqueous liquid is combined on the steel sheet surface. In the process of drying, the formation of a complex salt by the metal ions contained and the deposition of a dense titanium oxide-based coating component results in the formation of a coating with a high corrosion-inhibiting ability. By using a nonionic bisphenol A type epoxy resin, it is considered that resistance to the alkali at the interface generated during electrodeposition coating can be imparted and excellent electrodeposition coating adhesion can be obtained.

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. When the condensation degree exceeds 30, a white precipitate is formed when mixed with hydrogen peroxide, and a stable titanium-containing aqueous liquid cannot be obtained.
The hydrolyzable titanium compounds listed above, low-condensates of hydrolyzable 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.

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 a titanic acid (peroxotitanium hydrate) aqueous solution obtained by adding hydrogen peroxide water to a hydrous titanium oxide gel or sol (JP-A 63-35419, JP 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 resulting 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 liquid containing ultrafine particles of crystallized titanium oxide is obtained. When the heat treatment or autoclave treatment is less than 80 ° C., crystallization of titanium oxide does not proceed sufficiently. The titanium oxide dispersion thus produced has an average particle diameter of titanium oxide ultrafine particles of 10 nm or less, preferably about 1 to 6 nm. When the average particle diameter of the titanium oxide ultrafine particles is larger than 10 nm, the film forming property is deteriorated (when the film is dried after coating to form a film, cracking occurs at a film thickness of 1 μm or more), which is not preferable. 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).

By applying and drying the surface treatment composition (X ₀ ) containing the titanium-containing aqueous liquid (A) using the hydrolyzable titanium compound a on the surface of the plated steel sheet (for example, heat drying at a low temperature), the surface treatment composition (X ₀ ) A dense titanium oxide-containing film (surface treatment film) having excellent adhesion can be formed.
The heating temperature after applying the surface treatment composition (X ₀ ) is, for example, preferably 200 ° C. or lower, particularly preferably 150 ° C. or lower. ) Of titanium oxide-containing film can be formed.
Moreover, when the titanium oxide dispersion obtained through the heat treatment or autoclave treatment as described above at 80 ° C. or more is used as the titanium-containing aqueous liquid (A), only the surface treatment composition (X ₀ ) is applied. Since a crystalline titanium oxide-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 (ii), 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 of at least a crystallization temperature of anatase, for example, a temperature of 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 less than 1/99, the effect of adding the titanium oxide sol cannot be sufficiently obtained in terms of stability, photoreactivity, etc. On the other hand, if it exceeds 99/1, the film forming property is inferior. Absent.

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.
In addition, 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).

Like the titanium-containing aqueous liquid (A) using the hydrolyzable titanium compound a described above, the surface treatment composition (X ₀ ) containing the titanium-containing aqueous liquid (A1) is applied to the surface of the plated steel sheet and dried ( For example, by performing heat drying at a low temperature, a dense titanium oxide-containing film (surface treatment film) having excellent adhesion can be formed.
The heating temperature after applying the surface treatment composition (X ₀ ) is, for example, preferably 200 ° C. or less, particularly preferably 150 ° C. or less. By heating and drying at such a temperature, anatase-type titanium oxide containing some hydroxyl groups. A contained film 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 the hydrogen peroxide solution is less than 0.1 parts by mass in terms of hydrogen peroxide, chelate formation is not sufficient and white turbid precipitation occurs. On the other hand, if it exceeds 100 parts by mass, unreacted hydrogen peroxide tends to remain, and dangerous active oxygen is released during storage, which is not preferable.

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, silica, 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 composition (X) is 1 to 100 g / L, preferably 5 to 50 g / L in terms of solid content. It is preferable from the point.

  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 a large effect of improving the storage stability of the titanium-containing aqueous liquid (A). Among them, 1-hydroxyethane-1,1-diphosphonic acid has a particularly large effect. It is particularly preferred to use this.
The compounding amount of the organic phosphoric acid compound (B) is 1 to 400 parts by mass, particularly 20 to 300 parts by mass in terms of the solid content with respect to 100 mass parts of the solid content of the titanium-containing aqueous liquid (A). This is preferable from the viewpoint of water resistance adhesion. When the compounding amount of the organic phosphate 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 is inferior. Since it is inferior, it is not preferable.

The nonionic aqueous bisphenol A type epoxy resin (C) is a nonionic bisphenol A type epoxy resin that can be dissolved or dispersed in water. In the case of a cationized epoxy resin, an alkali at the interface generated during electrodeposition coating reacts with the cation resin, and the adhesion tends to be lowered. Therefore, the epoxy resin needs to be nonionic.
A conventionally known method can be used as a method for making a bisphenol A type epoxy resin water-soluble or water-dispersed in a nonionic system. For example, an epoxy emulsion in which an epoxy resin is dispersed in water in the presence of a nonionic surfactant. The technology for producing such an epoxy resin aqueous dispersion is a known technology. For example, in JP-A-9-510481, (a) 1.0 reaction equivalent of epoxy resin, (b) 0.005 to 0.005 A curable epoxy resin prepared by contacting 0.5 reaction equivalents of an amine-epoxy addition product, and optionally (c) about 0.01 to 1.0 reaction equivalents of a polyhydric phenol, said amine A curable epoxy resin wherein the epoxy addition product is obtained by contacting 1.0 equivalent of an aliphatic polyepoxide with a reaction equivalent of polyoxyalkyleneamine greater than 1.0 but not greater than about 2.5 Discloses a method for producing an aqueous dispersion by mixing with water. Specifically, there are Epiletz water-based epoxy resin series manufactured by Hexion Specialty Chemicals, Inc., Epiletts 6943, 3510W60, 3515W60, 3519W50, 3520WY55, 3522W60, 3540WY55, 5003W55, 6006W70 (all Product name).

The number average molecular weight of the nonionic water-based bisphenol A type epoxy resin (C) is not particularly specified, but from the viewpoint of obtaining particularly excellent electrodeposition coating adhesion, the number average molecular weight is preferably 1000 to 8000, particularly It is desirable to use the one of 2000 to 5000. Although this resin also has a role as a binder for the film, if the number average molecular weight is less than 1000, the adhesion tends to deteriorate, whereas if it exceeds 8000, the film formability decreases and the adhesion tends to decrease. is there.
Two or more nonionic aqueous bisphenol A type epoxy resins may be used in combination.

  The compounding amount of the nonionic aqueous bisphenol A type epoxy resin (C) is 10 to 2000 parts by mass, particularly 100 to 1500 parts by mass in terms of the solid content with respect to 100 parts by mass of the solid content of the titanium-containing aqueous liquid (A). It is preferable from the viewpoints of corrosion resistance after the film is alkali-degritted, electrodeposition coating adhesion, adhesive strength, and the like. When the compounding amount of the nonionic aqueous bisphenol A type epoxy resin (C) is less than 10 parts by mass with respect to 100 parts by mass of the solid content of the titanium-containing aqueous liquid (A), the corrosion resistance deteriorates. Corrosion resistance and adhesion after electrodeposition are deteriorated, which is not preferable.

The vanadate compound (D) improves the anticorrosive property of the film obtained by the surface treatment composition. For example, vanadate, lithium orthovanadate, sodium orthovanadate, lithium metavanadate, potassium metavanadate, Examples thereof include sodium metavanadate, ammonium metavanadate, sodium pyrovanadate, vanadyl chloride, and vanadyl sulfate. 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 amount of the vanadic acid compound (D) is 1 to 400 parts by mass, particularly 10 to 400 parts by mass in terms of the solid content with respect to 100 mass parts of the solid content of the titanium-containing aqueous liquid (A). From the viewpoint of corrosion resistance after alkali degreasing. When the compounding amount of the vanadic acid compound (D) 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 deteriorates. Since corrosion resistance is inferior, it is not preferable.

Examples of the zirconium fluoride compound (E) include salts of zirconium hydrofluoric acid such as sodium, potassium, lithium, and ammonium, and one or more of these can be used. Of these, ammonium zirconium fluoride is preferable from the viewpoint of water-resistant adhesion.
The compounding amount of the zirconium fluoride compound (E) is 1 to 400 parts by weight, particularly 20 to 400 parts by weight, based on the solid content of 100 parts by weight of the titanium-containing aqueous liquid (A). This is preferable from the viewpoint of corrosion resistance after alkali degreasing of the film. If the blending amount of the zirconium fluoride compound (E) 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 deteriorates. This is not preferable because of its poor corrosion resistance.

Examples of the zirconium carbonate compound (F) include salts of zirconium carbonate such as sodium, potassium, lithium, and ammonium, and one or more of these can be used. Of these, ammonium zirconium carbonate is preferable from the viewpoint of water-resistant adhesion.
The coating amount of the zirconium carbonate compound (F) is 1 to 400 parts by mass, particularly 10 to 400 parts by mass in terms of the solid content with respect to 100 mass parts of the solid content of the titanium-containing aqueous liquid (A). From the viewpoint of corrosion resistance after alkali degreasing. When the compounding amount of the zirconium carbonate compound (F) 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 deteriorates. Since corrosion resistance is inferior, it is not preferable.

A silane coupling agent can be further added to the surface treatment composition (X) as necessary. Examples of the silane coupling agent include N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, N- β (N-vinylbenzylaminoethyl) γ-aminopropyltrimethoxysilane hydrochloride, γ-glycidoxypropyltrimethoxysilane, γ-mercaptopyrrolotrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, methyltrimethoxy Silane, vinyltriacetoxysilane, γ-chloropropyltrimethoxysilane, hexamethyldisilazane, γ-anilinopropyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, octadecyldimethyl [3- (trimethoxysilane Yl) propyl] ammonium chloride, trimethylchlorosilane, and the like, and one or more of these may be used.
The compounding amount of the silane coupling agent is 1 to 400 parts by weight, particularly 10 to 400 parts by weight, based on 100 parts by weight of the solid content of the titanium-containing aqueous liquid (A). From the point of view, it is preferable.

If necessary, organic fine particles and / or inorganic fine particles can be further added to the surface treatment composition (X). By adding such fine particles, the transparency of the coating film is lowered, and nitrite (interference color) that is likely to occur in a thin film can be suppressed, making it particularly suitable for applications in which appearance is important. The fine particles preferably have an average particle size of 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 particularly preferable.
The blending 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 the solid content of the surface treatment composition (X) from the viewpoint of corrosion resistance and the like.

If necessary, the surface treatment composition (X) further includes an etching agent such as an inorganic phosphoric acid compound or hydrofluoric acid, a heavy metal compound other than the components specified by the present invention, an aqueous organic polymer compound, a thickener. , Surfactants, rust preventives (tannic acid, phytic acid, benzotriazole, etc.), colored pigments, extender pigments, silica, rust preventive pigments, and the like can be added.
The surface treatment composition (X) is usually diluted with water and used. If necessary, for example, a hydrophilic solvent such as methanol, ethanol, isopropyl alcohol, an ethylene glycol solvent, or a propylene glycol solvent. It may be diluted with.
Since the surface treatment composition (X) becomes a stable liquid in a neutral or acidic region, pH 1 to 7, particularly 1 to 5 is particularly preferable.
The film thickness of the surface treatment film formed by the surface treatment composition (X) is from 0.01 to 1.0 μm, preferably from 0.05 to 0.00 μm, from the viewpoints of economy and coating film performance, particularly corrosion resistance and adhesion. 7 μm. If the film thickness is less than 0.01 μm, sufficient corrosion resistance cannot be obtained. On the other hand, if it exceeds 1.0 μm, weldability and corrosion resistance after alkaline degreasing deteriorate.

The surface-treated steel sheet of the present invention can further improve the corrosion resistance by forming an organic film on the surface-treated film.
This organic film is a film having a film thickness of 0.1 to 5.0 μm and does not contain chromium (however, excluding chromium as an inevitable impurity). There are no particular restrictions on the components of the organic coating, but particularly from the viewpoint of corrosion resistance, the main component of the resin composition is the coating-forming organic resin (G) and a hydrazine derivative in which some or all of the compounds have active hydrogen ( It is preferably formed by applying a coating composition which is a reaction product (= base resin (R)) with the active hydrogen-containing compound (H) comprising I) and drying. Hereinafter, the organic film of this preferred embodiment will be described.

  As the kind of the film-forming organic resin (G), a part or all of the compounds react with the active hydrogen-containing compound (H) comprising the hydrazine derivative (I) having active hydrogen, and the film-forming organic resin contains active hydrogen. There is no particular limitation as long as the compound (H) can be bonded by a reaction such as addition or condensation and can form a film appropriately. Examples of the film-forming organic resin (G) include epoxy resins, modified epoxy resins, polyurethane resins, polyester resins, alkyd resins, acrylic copolymer resins, polybutadiene resins, phenol resins, and adducts of these resins or A condensate etc. can be mentioned, One of these can be used individually or in mixture of 2 or more types.

  The film-forming organic resin (G) is particularly preferably an epoxy group-containing resin (J) containing an epoxy group in the resin from the viewpoints of reactivity, easiness of reaction, anticorrosion, and the like. As this epoxy group-containing resin (J), a part or all of the compounds react with the active hydrogen-containing compound (H) composed of the hydrazine derivative (I) having active hydrogen to form an active hydrogen-containing compound in the film-forming organic resin. There is no particular limitation as long as (H) is a resin that can be bonded by a reaction such as addition or condensation and can form a film appropriately. For example, an acrylic resin copolymerized with an epoxy resin, a modified epoxy resin, or an epoxy group-containing monomer. Examples thereof include copolymer resins, 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 may be used alone or in combination of two or more. It can be used by mixing.

  Of these epoxy group-containing resins (J), epoxy resins and modified epoxy resins are particularly preferred from the viewpoints of adhesion to the plating surface and corrosion resistance. Among them, thermosetting epoxy resins and modified epoxy resins that have excellent barrier properties against corrosion factors such as oxygen are the most suitable, and in particular, the amount of coating to obtain high conductivity and spot weldability. It is particularly advantageous when the level is low.

  As the epoxy resin, polyphenols such as bisphenol A, bisphenol F, and novolac type phenol are reacted with epihalohydrin such as epichlorohydrin to introduce glycidyl groups, or polyphenols are further added to the glycidyl group introduction reaction product. An aromatic epoxy resin obtained by reacting with an aromatic epoxy resin, an aliphatic epoxy resin, an alicyclic epoxy resin, and the like. These may be used alone or in admixture of two or more. Can do. These epoxy resins preferably have a number average molecular weight of 1500 or more, particularly when film formation at low temperatures is required.

Examples of the modified epoxy resin include resins obtained by reacting various modifiers with epoxy groups or hydroxyl groups in the epoxy resin, such as epoxy ester resins reacted with drying oil fatty acids, acrylic acid, methacrylic acid, etc. An epoxy acrylate resin modified with a polymerizable unsaturated monomer component containing styrene, a urethane-modified epoxy resin reacted with an isocyanate compound, and the like can be exemplified.
As the acrylic copolymer resin copolymerized with the epoxy group-containing monomer, an unsaturated monomer having an epoxy group and a polymerizable unsaturated monomer component essentially comprising an acrylic ester or a methacrylic ester, a solution polymerization method, Examples thereof include resins synthesized by an emulsion polymerization method or a suspension polymerization method.

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. .
The acrylic copolymer resin 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.

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、特に好ましくは２〜２０である。
なお、皮膜形成有機樹脂（Ｇ）は、有機溶剤溶解型、有機溶剤分散型、水溶解型、水分散型のいずれであってもよい。 Particularly preferable as the epoxy resin is a resin having a chemical structure represented by the following formula, which is a reaction product of bisphenol A and epihalohydrin, and this epoxy resin is particularly preferable because of its excellent corrosion resistance.

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, Most preferably, it is 2-20.
The film-forming organic resin (G) may be any of an organic solvent dissolution type, an organic solvent dispersion type, a water dissolution type, and a water dispersion type.

The organic film of the present embodiment aims to provide a hydrazine derivative in the molecule of the film-forming organic resin (G), and therefore at least a part (preferably all) of the active hydrogen-containing compound (H) is The hydrazine derivative (I) having active hydrogen is required.
In the case where the film-forming organic resin (G) is an epoxy group-containing resin, examples of the active hydrogen-containing compound (H) that reacts with the epoxy group include those shown below. In this case as well, at least a part (preferably all) of the active hydrogen-containing compound (H) needs to be a hydrazine derivative having active hydrogen.
・ Hydrazine derivatives with active hydrogen ・ Primary or secondary amine compounds with active hydrogen ・ Organic acids such as ammonia and carboxylic acids ・ Halogen halides such as hydrogen chloride ・ Alcohols and thiols ・ Having active hydrogen Quaternary chlorinating agent which is a mixture of hydrazine derivative or tertiary amine and acid

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, dodecanoic acid dihydrazide, isophthalic acid dihydrazide, thiocarbohydrazide, 4,4'-oxybisbenzenesulfonylhydrazide, benzophenone hydrazone, aminopolyacrylamide Hydrazide compounds such as;
(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, 5-amino -3-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 5-amino-2-mercapto-1,3,4-thiadiazole and 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 can be used individually by 1 type or in mixture of 2 or more types.

Typical examples of the amine compound having active hydrogen that can be used as a part of the active hydrogen-containing compound (H) include the following.
(A) 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;
(B) secondary monoamines such as diethylamine, diethanolamine, di-n- or -iso-propanolamine, N-methylethanolamine, N-ethylethanolamine;
(C) a secondary amine-containing compound obtained by adding a monoalkanolamine such as monoethanolamine and a dialkyl (meth) acrylamide by a Michael addition reaction;
(D) 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;

The quaternary chlorinating agent that can be used as a part of the active hydrogen-containing compound (H) is a hydrazine derivative or a tertiary amine that does not have active hydrogen and is not reactive with an epoxy group by itself. In order to be able to react with the acid. 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. Examples of the hydrazine derivative having no active hydrogen used for obtaining a quaternary chlorinating agent include 3,6-dichloropyridazine, and examples of the tertiary amine include dimethylethanolamine, triethylamine, Examples include trimethylamine, triisopropylamine, and methyldiethanolamine.

The reaction product of the film-forming organic resin (G) and the active hydrogen-containing compound (H) composed of the hydrazine derivative (I) in which a part or all of the compounds have active hydrogen is the film-forming organic resin (G) and the active hydrogen. It is obtained by reacting the containing compound (H) 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, and the type 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, cyclohexanone; ethanol, butanol, 2-ethylhexyl alcohol, benzyl alcohol, ethylene glycol, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether , Propylene glycol, propylene glycol monomethyl ether, diethylene glycol, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether and other alcohols and ethers containing hydroxyl groups; ethyl acetate, butyl acetate, ethylene glycol monobutyl ether acetate and other esters; toluene, xylene Aromatic hydrocarbons etc. Illustration can, it is possible to use one 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 film-forming organic resin (G) and the active hydrogen-containing compound (H) composed of a hydrazine derivative (I) in which some or all of the compounds have active hydrogen is a solid content ratio. ) The active hydrogen-containing compound (H) is desirably 0.5 to 20 parts by mass, particularly preferably 1.0 to 10 parts by mass with respect to 100 parts by mass.
When the film-forming organic resin (G) is an epoxy group-containing resin (J), the blending ratio of the epoxy group-containing resin (J) and the active hydrogen-containing compound (H) is determined by the active hydrogen-containing compound (H ) And the number of epoxy groups in the epoxy group-containing resin (J) [number of active hydrogen groups / number of epoxy groups] is 0.01 to 10, more preferably 0.1 to 8, and still more preferably. It is appropriate to set it to 0.2-4 from points, such as corrosion resistance.

  Moreover, the ratio of the hydrazine derivative (I) having active hydrogen in the active hydrogen-containing compound (H) is 10 to 100 mol%, more preferably 30 to 100 mol%, still more preferably 40 to 100 mol%. Is appropriate. If the ratio of the hydrazine derivative (I) having active hydrogen is less than 10 mol%, the organic film cannot be provided with a sufficient anti-rust function, and the resulting anti-rust effect is simply mixing the film-forming organic resin and the hydrazine derivative. It is no different from the case of using it.

In this embodiment, in order to form a dense barrier film, it is desirable to mix a curing agent in the resin composition and heat cure the organic film (upper film).
As a curing method for forming a resin composition film, (1) a curing method using a urethanization reaction between an isocyanate and a hydroxyl group in a base resin, and (2) 1 selected from melamine, urea and benzoguanamine An etherification reaction between an alkyl etherified amino resin obtained by reacting a monohydric alcohol having 1 to 5 carbon atoms with a part or all of a methylol compound obtained by reacting formaldehyde with a seed or more and a hydroxyl group in a base resin. The curing method to be used is suitable, and among these, it is particularly preferable to use a urethanization reaction between isocyanate and a hydroxyl group in the base resin as a main reaction.

The polyisocyanate compound used in the curing method (1) above is composed of an aliphatic, alicyclic (including heterocyclic) or aromatic isocyanate compound having at least two isocyanate groups in one molecule, or many of these compounds. A compound partially reacted with a monohydric alcohol is preferred. Examples of such polyisocyanate compounds include the following.
(I) m- or p-phenylene diisocyanate, 2,4- or 2,6-tolylene diisocyanate, o- or p-xylylene diisocyanate, hexamethylene diisocyanate, dimer acid diisocyanate, isophorone diisocyanate (ii) above (i) Or a mixture thereof and a polyhydric alcohol (dihydric alcohols such as ethylene glycol and propylene glycol; trihydric alcohols such as glycerin and trimethylolpropane; tetrahydric alcohols such as pentaerythritol; sorbitol, dipentaerythritol, etc. A compound of at least two isocyanates in one molecule. These polyisocyanate compounds may be used alone or in combination of two or more. It can be.

Moreover, as a protective agent (blocking agent) of a polyisocyanate compound, for example,
(1) Aliphatic monoalcohols such as methanol, ethanol, propanol, butanol, octyl alcohol (2) Ethylene glycol and / or diethylene glycol monoethers such as methyl, ethyl, propyl (n-, iso), butyl ( n-, iso, sec) monoethers (3) phenols, aromatic alcohols such as cresol (4) oximes such as acetooxime, methyl ethyl ketone oxime, etc., and one or more of these and the polyisocyanate By reacting with the compound, a polyisocyanate compound that is stably protected at least at room temperature can be obtained.

Such a polyisocyanate compound (K) is preferably (R) / (K) = 95/5 to 55/45 (weight ratio of nonvolatile content), more preferably as a curing agent with respect to the base resin (R). It is appropriate to blend at a ratio of (R) / (K) = 90/10 to 65/35. When the blending amount of the polyisocyanate compound (K) is less than (R) / (K) = 95/5, the effect as a curing agent may be insufficient. In addition, since the polyisocyanate compound (K) has water absorption, if it is added more than (R) / (K) = 55/45, the adhesion of the upper layer film is deteriorated, and the upper layer film is further overcoated. When coating is performed, the unreacted polyisocyanate compound moves into the coating film, which causes inhibition of curing of the coating film and poor adhesion.
The base resin (R) is sufficiently crosslinked by the addition of the crosslinking agent (curing agent) as described above, but it is desirable to use a known curing accelerating catalyst in order to further increase the low temperature crosslinking property. Examples of the curing accelerating catalyst include N-ethylmorpholine, dibutyltin dilaurate, cobalt naphthenate, stannous chloride, zinc naphthenate, and bismuth nitrate.
For example, when an epoxy group-containing resin is used for the film-forming organic resin (G), a known acrylic, alkyd, polyester, or other resin is mixed with the epoxy group-containing resin for the purpose of slightly improving physical properties such as adhesion. It can also be used.

The organic coating (coating composition) may contain a non-chromium rust preventive additive as necessary for the purpose of improving the corrosion resistance. By including such a non-chromium rust preventive additive in the organic coating, more excellent anticorrosion performance can be obtained.
In particular, it is preferable to use one or more selected from the following (a) to (e) as the non-chromium-based rust preventive additive.
(A) silicon oxide (b) calcium compound (c) poorly soluble phosphate compound (d) molybdate compound (e) one or more selected from triazoles, thiols, thiadiazoles, thiazoles, thiurams , Organic compounds containing S atoms

The details and anticorrosion mechanism of the non-chromium rust preventive additives (a) to (e) are as follows.
First, as the component (a), colloidal silica or dry silica, which is fine particle silica, can be used. From the viewpoint of corrosion resistance, calcium ion-exchanged silica in which calcium is bonded to the surface is used. Is desirable.
As colloidal silica, for example, SNOWTEX O, 20, 30, 40, C, S (all trade names) manufactured by Nissan Chemical Co., Ltd. can be used, and as fumed silica, Nippon Aerosil ( AEROSIL made by
R971, R812, R811, R974, R202, R805, 130, 200, 300, 300CF (all are trade names) can be used. As calcium ion exchange silica, WRGrace & Co. SHIELDEX C303, SHIELDEX made
AC3, SHIELDEX AC5 (all are trade names), SHIELDEX, SHIELDEX SY710 (all are trade names) manufactured by Fuji Silysia Chemical Co., Ltd., and the like can be used. These silicas contribute to the production of dense and stable zinc corrosion products in a corrosive environment, and the corrosion products are formed densely on the plating surface, thereby suppressing the promotion of corrosion.

In addition, the above components (b) and (c) exhibit particularly excellent anticorrosion performance (self-repairing property) due to precipitation.
The calcium compound as the component (b) 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. In the component (b), base metal is preferentially dissolved in the corrosive environment over zinc and aluminum, which are plating metals, and this seals the defective part as a dense and poorly soluble product with OH ⁻ produced by the cathode reaction. And suppress the corrosion reaction. Moreover, when it mix | blends with the above silicas, a calcium ion adsorb | sucks to the surface and neutralizes a surface charge electrically and aggregates. As a result, a dense and sparingly soluble protective film is formed to block the corrosion and suppress the corrosion reaction.

  Moreover, as a poorly soluble phosphoric acid compound which is said (c), a hardly soluble phosphate can be used. This sparingly soluble phosphate 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 poorly soluble zinc phosphate, magnesium phosphate, calcium phosphate, aluminum phosphate, may be sufficient. 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, orthophosphate may be polyphosphate other than orthophosphate. Includes all condensed phosphates such as salts. By using this poorly soluble phosphorus compound, the plating metal zinc or aluminum eluted by corrosion reacts with the phosphate ions dissociated by hydrolysis to form a dense and sparingly soluble protective film. The corrosion starting point is blocked, and the corrosion reaction is suppressed.

  In addition, as the molybdate compound (d), for example, molybdate can be used. The molybdate 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 a phosphomolybdate etc. are mentioned as a double salt. Molybdate compounds exhibit self-repairing properties due to the passivating effect. That is, by forming a dense oxide on the plating film surface together with dissolved oxygen in a corrosive environment, the corrosion starting point is blocked and the corrosion reaction is suppressed.

  Moreover, as an organic compound of said (e), the following can be mentioned, for example. That is, as triazoles, 1,2,4-triazole, 3-amino-1,2,4-triazole, 3-mercapto-1,2,4-triazole, 5-amino-3-mercapto-1,2 1,4-triazole, 1H-benzotriazole, etc., and as thiols, 1,3,5-triazine-2,4,6-trithiol, 2-mercaptobenzimidazole, etc., and as thiadiazoles, 5- Amino-2-mercapto-1,3,4-thiadiazole, 2,5-dimercapto-1,3,4-thiadiazole and the like, and as thiazoles, 2-N, N-diethylthiobenzothiazole, 2-mercapto Examples include benzothiazoles, and examples of thiurams include tetraethylthiuram disulfide. It is. These organic compounds exhibit self-repairing properties due to the adsorption effect. That is, zinc and aluminum eluted by corrosion are adsorbed on polar groups containing sulfur contained in these organic compounds to form an inert film, thereby blocking the corrosion starting point and suppressing the corrosion reaction.

The compounding amount of the non-chromium rust preventive additive is 0.1 to 50 parts by mass, preferably 0.5 to 30 parts by mass, relative to 100 parts by mass of the solid content of the resin composition for film formation. The part is appropriate. If the blending amount of the non-chromium rust preventive additive is less than 0.1 parts by mass, the effect of improving the corrosion resistance after alkaline degreasing cannot be sufficiently obtained, while if it exceeds 50 parts by mass, the paintability, workability and weldability are increased. Is not preferable because the corrosion resistance is also lowered.
Two or more rust preventive additives (a) to (e) may be added in combination. In this case, since the inherent anticorrosive action is combined, higher corrosion resistance can be obtained. In particular, calcium ion-exchanged silica is used as the component (a), and one or more of the components (c), (d), (e), particularly preferably the components (c) to (e). When all are added in combination, particularly excellent corrosion resistance is obtained.

  In addition to the above rust preventive additive components, other oxide fine particles (for example, aluminum oxide, zirconium oxide, titanium oxide, cerium oxide, antimony oxide) are added to the organic coating (coating composition) as a corrosion inhibitor. ), Phosphomolybdate (eg, aluminum phosphomolybdate), organophosphoric acid and its salts (eg, phytic acid, phytate, phosphonic acid, phosphonate, and metal salts thereof, alkali metal salts, 1 type, or 2 or more types, such as an alkaline-earth metal salt etc.) and organic inhibitors (for example, a hydrazine derivative, a thiol compound, a dithiocarbamate etc.) can be added.

A solid lubricant can be blended in the organic coating (coating composition) for the purpose of improving the workability of the coating, if necessary.
Suitable solid lubricants include, for example, the following, and one or more of these can be used.
(1) Polyolefin wax, paraffin wax: For example, polyethylene wax, synthetic paraffin, natural paraffin, micro wax, chlorinated hydrocarbon, etc. (2) Fluorine resin fine particles: For example, polyfluoroethylene resin (polytetrafluoroethylene resin, etc.) In addition to these, fatty acid amide compounds (for example, stearic acid amide, palmitic acid amide, methylene bisstearamide, ethylene bisstearamide, oleic acid amide, esyl) Acid amides, alkylene bis fatty acid amides), metal soaps (eg, calcium stearate, lead stearate, calcium laurate, calcium palmitate, etc.), metal sulfides (eg, molybdenum disulfide, tungsten disulfide) ), Graphite, fluorinated graphite, boron nitride, polyalkylene glycol, alkali metal sulfate or the like may be used.

Among the above solid lubricants, polyethylene wax and fluororesin fine particles (in particular, polytetrafluoroethylene resin fine particles) are preferable.
Examples of polyethylene waxes include Clariant Japan Co., Ltd. Selidust 9615A, Selidust 3715, Selidust 3620, Selidust 3910 (all trade names), Sanyo Chemical Co., Ltd. Sun Wax 131-P, Sun Wax 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. can be used. .

The fluororesin fine particles are most preferably tetrafluoroethylene fine particles. For example, Lubron L-2 and Lubron L-5 (both trade names) manufactured by Daikin Industries, Ltd., Mitsui DuPont Fluoro Chemical Co., Ltd. MP1100, MP1200 (all are trade names), full-on dispersion AD1, full-on dispersion AD2, full-on L141J, full-on L150J, and full-on L155J (all are trade names) manufactured by Asahi Glass Co., Ltd. are preferable.
Among these, a particularly excellent lubricating effect can be expected by the combined use of polyolefin wax and tetrafluoroethylene fine particles.
As the solid lubricant in the organic film is added in a larger amount, the effect of improving the lubricity is increased. However, it is preferable to add the solid lubricant in a range satisfying other film performance, and the solid content of the resin composition for film formation is 100. It is desirable that the solid content is preferably 1 to 30 parts by mass, more preferably 1 to 10 parts by mass with respect to mass parts. If the blending amount of the solid lubricant is less than 1 part by mass, the effect of improving the lubricity is poor. On the other hand, if the blending amount exceeds 30 parts by mass, the paintability deteriorates, which is not preferable.

  Organic film (coating composition) is a reaction product (resin) of a film-forming organic resin (G) and an active hydrogen-containing compound (H) comprising a hydrazine derivative (I) in which some or all of the compounds have active hydrogen Composition) as a main component, and a curing agent, a non-chromium anticorrosive additive, a solid lubricant and the like are added to the main component as necessary. Further, an organic coloring pigment (for example, an additive) , Condensed polycyclic organic pigments, phthalocyanine organic pigments, etc.), colored dyes (eg, organic solvent-soluble azo dyes, water-soluble azo metal dyes, etc.), inorganic pigments (eg, titanium oxide), chelating agents (eg, , Thiol, etc.), conductive pigment (eg, metal powder such as zinc, aluminum, nickel, etc.), iron phosphide, antimony-doped tin oxide, etc., coupling agent (eg, silane coupling) , Titanium coupling agent) may be added to one or more of melamine-cyanuric acid adduct.

Moreover, the coating composition for film formation containing the said main component and an additional component normally contains a solvent (an organic solvent and / or water), and also a neutralizer etc. are added as needed.
The organic solvent is not particularly limited as long as it can dissolve or disperse the reaction product of the film-forming organic resin (G) and the active hydrogen-containing compound (H) and can be prepared as a coating composition. The various organic solvents exemplified above can be used.
The neutralizing agent is blended as necessary to neutralize the film-forming organic resin (G) to make it water-based. When the film-forming organic resin (G) is a cationic resin, Acids such as acetic acid, lactic acid and formic acid can be used as a neutralizing agent.
The film thickness of the organic film is preferably 0.1 to 5.0 μm, more preferably 0.5 to 2.0 μm. When the film thickness of the organic film is less than 0.1 μm, the effect of improving the corrosion resistance is insufficient. On the other hand, when the film thickness exceeds 5.0 μm, the weldability and electrodeposition coating adhesion deteriorate.

Next, the manufacturing method of the surface treatment steel plate of this invention is demonstrated.
In order to form a surface treatment film on the surface of a zinc-based plated steel sheet or an aluminum-based plated steel sheet, a surface treatment composition (treatment liquid) having the above-described composition is applied to the surface of the plated steel sheet so that the dry film thickness is in the above range. And heat-dried without washing with water.
As a method of coating the surface treatment composition on the surface of the plated steel sheet, any of an application method, a dipping 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. In addition, after the coating process or dipping process using a squeeze coater or the like, or the spray process, 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 coating the surface treatment composition, drying is performed 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. Heat drying is preferably performed in the range of 30 to 200 ° C., more preferably 40 to 140 ° C. at the ultimate plate temperature. If the heating and drying temperature is less than 30 ° C., a large amount of moisture remains in the film, and the corrosion resistance tends to be insufficient. On the other hand, when the heating and drying temperature exceeds 200 ° C., not only is it uneconomical, but defects are generated in the film, and the corrosion resistance tends to decrease.
By forming an organic film as a second layer film on the surface treatment film formed as described above, the remarkably excellent corrosion resistance is exhibited. The coating composition for organic coating is applied to the surface-treated coating surface so as to have the above-described film thickness, and dried by heating. Application | coating of a coating composition should just be performed according to the method used for formation of the surface treatment film mentioned above.

After application of the coating composition, drying is usually performed without washing with water, but a washing process may be performed after application of the coating composition. For the heat drying treatment, 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 30 to 300 ° C., preferably 40 to 140 ° C., at the ultimate plate temperature. If the heating and drying temperature is less than 30 ° C., a large amount of moisture and organic solvent remain in the film, and the corrosion resistance tends to be insufficient. On the other hand, when the heating and drying temperature exceeds 300 ° C., not only is it uneconomical, but defects occur in the film, and the corrosion resistance tends to decrease.
In addition, the film form prescribed by the present invention may be formed on either one side or both sides of the plated steel sheet. As a combination of the film forms on the front and back surfaces of the plated steel sheet, for example, surface treatment film + organic film / no treatment, It can be in any form such as surface treatment film + organic film / surface treatment film, surface treatment film + organic film / surface treatment film + organic film.

[Surface treatment composition for surface treatment film (first layer)]
Titanium-containing aqueous liquids A1 to A7, organic phosphoric acid compounds B1 to B6, aqueous organic resins C1 to C6, vanadic acid compounds D1 to D3, zirconium fluoride compounds E1 to E3, zirconium carbonate compounds F1 to F1 used for the surface treatment composition F3 is shown below. These components were blended in the proportions shown in Tables 1 and 2 to obtain surface treatment compositions P1 to P49.

(1) Production and production example 1 of titanium-containing aqueous liquids A1 to A7
Ammonia water (1: 9) was added dropwise to a solution in which 5 cc of a titanium tetrachloride 60% solution was made 500 cc with distilled water to precipitate titanium hydroxide. After washing with distilled water, 10 cc of a 30% hydrogen peroxide solution was added and stirred to obtain a yellow translucent viscous titanium-containing aqueous liquid A1 containing titanium.
・ Production example 2
A mixture of 10 parts by mass of tetraiso-propoxytitanium and 10 parts by mass of iso-propanol was dropped into a mixture of 10 parts by mass of 30% hydrogen peroxide and 100 parts by mass of deionized water with stirring at 20 ° C. over 1 hour. . Thereafter, the mixture was aged at 25 ° C. for 2 hours to obtain a yellow transparent, slightly viscous titanium-containing aqueous liquid A2.

・ Production Example 3
A titanium-containing aqueous liquid A3 was obtained under the same production conditions as in Production Example 2 except that tetra-n-butoxytitanium was used instead of tetraiso-propoxytitanium used in Production Example 2.
・ Production Example 4
A titanium-containing aqueous liquid A4 was obtained under the same production conditions as in Production Example 2 except that a tetramer of tetraiso-propoxytitanium was used instead of tetraiso-propoxytitanium used in Production Example 2.
・ Production Example 5
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. A5 was obtained.

・ Production Example 6
The titanium-containing aqueous liquid A3 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 A6.
・ Production Example 7
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% hydrogen peroxide solution 10 The mixture was added dropwise to a mixture of parts by mass and 100 parts by mass of deionized water at 10 ° C. with stirring for 1 hour. Thereafter, the mixture was aged at 10 ° C. for 24 hours to obtain a yellow transparent slightly viscous titanium-containing aqueous liquid A7.

(2) Organophosphate compounds B1 to B6
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: 3 -Phosphonobutane-1,2,4-tricarboxylic acid B6: potassium 2-hydroxyphosphonoacetate

(3) Aqueous (water-soluble or water-dispersible) organic resins C1 to C6
C1: “Epiletz 6943” (trade name, manufactured by Hexion Specialty Chemicals, Inc., nonionic aqueous bisphenol A type epoxy resin), number average molecular weight: 370
C2: “Epiletz 3520WY55” (trade name, manufactured by Hexion Specialty Chemicals, Inc., nonionic aqueous bisphenol A type epoxy resin), number average molecular weight: 900
C3: “Epiletz 3540WY55” (trade name, manufactured by Hexion Specialty Chemicals, Inc., nonionic aqueous bisphenol A type epoxy resin), number average molecular weight: 2900
C4: “Adeka Resin EM-0718” (trade name, manufactured by ADEKA Corporation, cationic aqueous epoxy resin)
C5: “Superflex E-2500” (trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., water-based polyurethane resin)
C6: “Vaironal MD-1100” (trade name, manufactured by Toyobo Co., Ltd., water-based polyester resin)

(4) Vanadic acid compounds D1 to D3
D1: ammonium metavanadate D2: sodium metavanadate D3: potassium metavanadate (5) zirconium fluoride compounds E1 to E3
E1: Ammonium zirconium fluoride E2: Sodium zirconium fluoride E3: Zirconium potassium fluoride (6) Zirconium carbonate compounds F1 to F3
F1: Ammonium zirconium carbonate F2: Sodium zirconium carbonate F3: Lithium zirconium carbonate

[Coating composition for organic coating (second layer)]
Base resins R1 to R4, curing agents K1 to K4, curing catalysts N1 to N4, rust preventive additives L1 to L6, and solid lubricants M1 to M3 used in the coating composition for organic coatings are shown below.
Curing agents K1 to K4 and curing catalysts N1 to N4 were appropriately blended with the base resins R1 to R4 to obtain resin compositions S1 to S12 shown in Table 3. S13 and S14 are commercially available organic resins.
For the resin composition shown in Table 3, rust preventive additives L1 to L6 and solid lubricants M1 to M3 are appropriately blended, and stirred for a predetermined time using a paint disperser (sand grinder). Table 4 Coating compositions Q1 to Q32 for forming an organic film as shown in FIG.

(1) Synthesis of base resins R1 to R4 <Synthesis Example 1>
jER828 (Japan Epoxy Resin Co., Ltd., epoxy equivalent 187) 1870 parts by weight, bisphenol A 912 parts by weight, tetraethylammonium bromide 2 parts by weight, methyl isobutyl ketone 300 parts by weight are charged into a four-necked flask and heated to 140 ° C. For 4 hours to obtain an epoxy resin having an epoxy equivalent of 1391 and a solid content of 90%. To this, 1500 parts by mass of ethylene glycol monobutyl ether was added and then 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 resin 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%. This is called base resin R1. This base resin R1 is a reaction product of a film-forming organic resin (G) and an active hydrogen-containing compound (H) containing 50 mol% of a hydrazine derivative (I) having active hydrogen.

<Synthesis Example 2>
jER1007 (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 to 120 ° C. to completely dissolve the epoxy resin in 1 hour. . This was cooled to 100 ° C., 168 parts by mass of 3-amino-1,2,4-triazole (molecular weight 84) was added, and the mixture was allowed to react for 6 hours until the epoxy group disappeared. 540 parts by mass was added to obtain a triazole-modified epoxy resin having a solid content of 60%. This is called base resin R2. This base resin R2 is a reaction product of the film-forming organic resin (G) and the active hydrogen-containing compound (H) containing 100 mol% of the hydrazine derivative (I) having active hydrogen.

<Synthesis Example 3>
A 4-necked flask was charged with 222 parts by mass of isophorone diisocyanate (isocyanate equivalent 111) and 34 parts by mass of methyl isobutyl ketone, maintained at 30 to 40 ° C., and 87 parts by mass of methyl ethyl ketoxime (molecular weight 87) was added dropwise over 3 hours. This was kept at 2 ° C. for 2 hours to obtain a partially blocked isocyanate having an isocyanate equivalent of 309 and a solid content of 90%.
Then, 1496 parts by weight of jER828 (Japan Epoxy Resin Co., Ltd., epoxy equivalent 187), 684 parts by weight of bisphenol A, 1 part by weight of tetraethylammonium bromide, and 241 parts by weight of methyl isobutyl ketone were charged into a four-necked flask and heated to 140 ° C. The mixture was allowed to react for 4 hours to obtain an epoxy resin having an epoxy equivalent of 1090 and a solid content of 90%. To this, 1000 parts by mass of methyl isobutyl ketone was added, and then cooled to 100 ° C., 202 parts by mass of 3-mercapto-1,2,4-triazole (molecular weight 101) was added, and 6 hours until the epoxy group disappeared. After the reaction, 230 parts by mass of the partially blocked isocyanate having a solid content of 90% was added and reacted at 100 ° C. for 3 hours to confirm that the isocyanate group had disappeared. Further, 461 parts by mass of ethylene glycol monobutyl ether was added to obtain a triazole-modified epoxy resin having a solid content of 60%. This is called base resin R3. This base resin R3 is a reaction product of a film-forming organic resin (G) and an active hydrogen-containing compound (H) containing 100 mol% of a hydrazine derivative (I) having active hydrogen.

<Synthesis Example 4>
jER828 (Japan Epoxy Resin Co., Ltd., epoxy equivalent 187) 1870 parts by weight, bisphenol A 912 parts by weight, tetraethylammonium bromide 2 parts by weight, methyl isobutyl ketone 300 parts by weight are charged into a four-necked flask and heated to 140 ° C. For 4 hours to obtain an epoxy resin having an epoxy equivalent of 1391 and a solid content of 90%. After adding 1500 parts by mass of ethylene glycol monobutyl ether to this, cooling to 100 ° C., adding 258 parts by mass of dibutylamine (molecular weight 129), reacting for 6 hours until the epoxy group disappears, and then cooling 225 parts by mass of methyl isobutyl ketone was added to obtain an epoxyamine adduct having a solid content of 60%. This is called base resin R4. This base resin R4 is a reaction product of a film-forming organic resin and an active hydrogen-containing compound that does not contain a hydrazine derivative having active hydrogen.

(2) Curing agents K1 to K4
K1: “Takenate B-870N” (trade name, manufactured by Mitsui Chemicals Polyurethanes, Inc., IPDI MEK oxime block)
K2: “Sumijoule BL3175” (trade name, Sumika Bayer Urethane Co., Ltd., isocinurate type block isocyanate)
K3: “Duranate MF-B80M” (trade name, Asahi Kasei Chemicals, HMDI MEK oxime block)
K4: “Cymel 325” (trade name, manufactured by Nippon Cytec Industries, Inc., imino group type melamine resin)
(3) Curing catalysts N1 to N4
N1: Dibutyltin dilaurate N2: Cobalt naphthenate N3: Stannous chloride N4: N-ethylmorpholine

(4) Rust preventive additives L1 to L6
L1: Calcium ion exchanged silica L2: Colloidal silica L3: Fumed silica L4: Aluminum dihydrogen triphosphate L5: Aluminum phosphomolybdate L6: Detraethyl thiuram disulfide (5) Solid lubricants M1 to M3
M1: “LUVAX1151” (trade name, manufactured by Nippon Seiwa Co., Ltd., polyethylene wax)
M2: “Seridust 3620” (trade name, Clariant Japan Co., Ltd., polyethylene wax)
M3: “MP1100” (trade name, manufactured by Mitsui DuPont Fluorochemical Co., Ltd., tetrafluoroethylene fine particles)

[Manufacture of surface-treated steel sheets]
The plated steel sheet shown in Table 5, which is a plated steel sheet for home appliances, building materials, and automobile parts based on cold-rolled steel sheets, was used as a processing original sheet. In addition, the thing of predetermined | prescribed board thickness was employ | adopted for the board thickness of the steel plate according to the objective of evaluation. After the surface of this plated steel sheet was subjected to alkaline degreasing treatment, washed with water and dried, the surface treatment composition was applied with a roll coater and dried by heating at various temperatures. The film thickness was adjusted by the solid content (heating residue) of the surface treatment composition or coating conditions (rolling force of roll, rotation speed, etc.).
Subsequently, the coating composition for forming an organic film was applied by a roll coater and dried by heating at various temperatures. The film thickness was adjusted by the solid content (heating residue) of the coating composition or the application conditions (roll rolling force, rotational speed, etc.).

Tables 6 to 9 show the results of evaluating the film composition and quality performance (white rust resistance, white rust resistance after alkali degreasing, electrodeposition coating adhesion, weldability) of the obtained surface-treated steel sheet. The quality performance was evaluated as follows.
(1) White rust resistance Each sample was subjected to a salt spray test (JIS-Z-2371), and the single-layer coating was evaluated by the white rust generation area ratio after 200 hours and the double-layer coating after 500 hours. . The evaluation criteria are as follows.
◎: White rust occurrence area ratio less than 5% ○: White rust occurrence area ratio 5% or more and less than 10% ○-: White rust occurrence area ratio 10% or more and less than 250% △: White rust occurrence area ratio 25% or more Less than 50% x: White rust generation area ratio 50% or more

(2) White rust resistance after alkali degreasing After each sample is degreased with alkali treatment liquid "CLN-364S" manufactured by Nihon Parker Lines Co., Ltd. under the conditions of spray treatment at 60 ° C for 2 minutes. Then, a salt spray test (JIS-Z-2371) was performed, and the white rust generation area ratio was evaluated after 100 hours for the single layer film and after 300 hours for the double layer film. The evaluation criteria are as follows.
◎: White rust generation area ratio less than 5% ○: White rust generation area ratio 5% or more and less than 10% ○-: White rust generation area ratio of 10% or more and less than 250% △: White rust generation area ratio of 25% or more Less than 50% x: White rust generation area ratio 50% or more

(3) Electrodeposition adhesion After applying a cationic electrodeposition paint (“GT-10” manufactured by Kansai Paint Co., Ltd.) to a thickness of 30 μm on each sample, baking was performed at 130 ° C. for 30 minutes. It was. The coated sample is immersed in warm water (40 ° C.) for 240 hours, immediately cut into grids (10 × 10, 1 mm interval), and attached and peeled off with adhesive tape. It was measured. The evaluation criteria are as follows.
◎: No peeling ○: Peeling area ratio less than 5% △: Peeling area ratio of 5% or more and less than 20% ×: Peeling area ratio of 20% or more

(4) Weldability For each sample, a welding test with continuous spotting was performed under the conditions of electrode used: CF-type Cr—Cu electrode, applied pressure: 200 kgf, energization time: 10 cycles / 50 Hz, welding current: 10 kA. The score was evaluated. The evaluation criteria are as follows.
◎: 2000 points or more ○: 1000 points or more, less than 2000 points △: 500 points or more, less than 1000 points ×: Less than 500 points

According to Tables 6 to 9, the present invention examples are excellent in white rust resistance and white rust resistance (corrosion resistance) after alkaline degreasing, electrodeposition coating adhesion, and weldability. On the other hand, in the comparative example, at least one of white rust resistance and white rust resistance (corrosion resistance) after alkaline degreasing, electrodeposition coating adhesion, and weldability is inferior to that of the present invention.
In Tables 1 and 2, * 1 to * 7 indicate the following contents.
* 1 Titanium-containing aqueous liquids A1 to A7 described in the main text of the specification
* 2 Organophosphate compounds B1 to B6 described in the specification text
* 3 Water-based organic resins C1 to C6 described in the specification text
* 4 Vanadic acid compounds D1 to D3 described in the specification text
* 5 Zirconium fluoride compounds E1 to E3 described in the specification text
* 6 Zirconium carbonate compounds F1 to F3 described in the specification text
* 7 Mass parts of solid content

In Tables 6 to 9, * 1 to * 3 indicate the following contents.
* 1 Plated steel sheets T1 to T9 listed in Table 5
* 2 Surface treatment compositions P1 to P49 described in Tables 1 and 2
* 3 Coating compositions Q1 to Q32 described in Table 4

Claims (10)

  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 an organic phosphoric acid compound (B), nonionic aqueous bisphenol A type epoxy 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. 10 to 2000 parts by mass of resin (C), 1 to 400 parts by mass of vanadic acid compound (D), 1 to 400 parts by mass of zirconium fluoride compound (E), and 1 to 400 parts of zirconium carbonate compound (F) It has a surface treatment film having a film thickness of 0.01 to 1.0 μm formed by applying and drying a surface treatment composition containing 400 parts by mass. Sex, excellent surface-treated steel sheet to electrodeposition coating adhesion and weldability.   The surface-treated steel sheet excellent in corrosion resistance, electrodeposition coating adhesion and weldability according to claim 1, wherein the nonionic aqueous bisphenol A type epoxy resin (C) has a number average molecular weight of 1000 to 8000.   The nonionic water-based bisphenol A-type epoxy resin (C) is a water-based bisphenol A-type epoxy resin having a polyoxyalkylene chain, and the corrosion resistance, electrodeposition coating adhesion and weldability according to claim 1 or 2 Excellent surface-treated steel sheet.   The corrosion resistance, electrodeposition coating adhesion and welding according to any one of claims 1 to 3, further comprising an organic film having a film thickness of 0.1 to 5.0 µm as an upper layer of the surface treatment film. Surface treated steel plate with excellent properties.   Reaction product of organic resin film composition comprising active film containing organic resin (G) and active hydrogen-containing compound (H) consisting of hydrazine derivative (I) in which some or all compounds have active hydrogen The surface-treated steel sheet excellent in corrosion resistance, electrodeposition coating adhesion and weldability according to claim 4.   6. The corrosion resistance and electrical resistance according to claim 4 or 5, wherein the organic coating contains 0.1 to 50 parts by mass of a non-chromium rust preventive additive with respect to 100 parts by mass of the solid content of the resin composition. Surface-treated steel sheet with excellent adhesion and weldability. The non-chromium rust preventive additive is at least one selected from the following (a) to (e): Excellent corrosion resistance, electrodeposition coating adhesion and weldability according to claim 6 Surface treated steel sheet.
(A) silicon oxide (b) calcium compound (c) poorly soluble phosphate compound (d) molybdate compound (e) one or more selected from triazoles, thiols, thiadiazoles, thiazoles, thiurams , Organic compounds containing S atoms   The corrosion resistance and electrodeposition coating adhesion according to any one of claims 4 to 7, wherein the organic film contains 1 to 30 parts by mass of a solid lubricant with respect to 100 parts by mass of the solid content of the resin composition. Surface-treated steel sheet with excellent weldability and weldability.   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 an organic phosphoric acid compound (B), nonionic aqueous bisphenol A type epoxy 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. 10 to 2000 parts by mass of resin (C), 1 to 400 parts by mass of vanadic acid compound (D), 1 to 400 parts by mass of zirconium fluoride compound (E), and 1 to 400 parts of zirconium carbonate compound (F) A surface treatment composition containing 400 parts by mass is applied and dried at an ultimate plate temperature of 30 to 200 ° C. to form a surface treatment film having a film thickness of 0.01 to 1.0 μm. Corrosion resistance characterized the door, electrodeposition coating adhesion and producing method of the excellent surface treatment steel sheet weldability.   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 an organic phosphoric acid compound (B), nonionic aqueous bisphenol A type epoxy 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. 10 to 2000 parts by mass of resin (C), 1 to 400 parts by mass of vanadic acid compound (D), 1 to 400 parts by mass of zirconium fluoride compound (E), and 1 to 400 parts of zirconium carbonate compound (F) By applying a surface treatment composition containing 400 parts by mass and drying at an ultimate plate temperature of 30 to 200 ° C., a surface treatment film with a film thickness of 0.01 to 1.0 μm is formed, A coating composition is applied to the upper layer and dried at an ultimate plate temperature of 30 to 300 ° C., thereby forming an organic film having a film thickness of 0.1 to 5.0 μm. A method for producing a surface-treated steel sheet having excellent adhesion to adhesion and weldability.