WO2011065581A1 - Surface-treating composition, and surface-treated steel sheet - Google Patents

Abstract

Disclosed is a surface-treating composition having excellent corrosion resistance, thermal discoloration resistance, blackening resistance, scratch resistance, and post-processing adhesion to an organic resin layer that is formed thereon. The surface-treating composition comprises (A) an aqueous titanium-containing solution produced by mixing at least one titanium compound selected from a hydrolysable titanium compound, a low-condensed product of a hydrolysable titanium compound, titanium hydroxide and a low-condensed product of titanium hydroxide with aqueous hydrogen peroxide, (B) a zirconium carbonate compound, (C) an organic phosphoric acid compound, (D) a metal phosphate salt, (E) silicon oxide, and (F) a water-soluble organic resin and/or a water-dispersible organic resin at a specified proportion.

Description

Surface treatment composition and surface treated steel sheet

The present invention is a surface treatment composition and a surface-treated steel sheet suitable for use in automobiles, home appliances, and building materials, and uses an environment-adaptive surface treatment composition that does not contain any hexavalent chromium in the composition or coating film. The present invention relates to a surface-treated steel sheet.

Conventionally, steel plates for home appliances, steel plates for building materials, and steel plates 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.

The chromate treatment uses hexavalent chromium which is a pollution control substance. This hexavalent chromium is treated in a closed system in the treatment process, and the sealing action by the organic film formed on the upper layer causes the chromate film to contain Since the elution of chromium from can be made almost zero, the human body and the environment are not substantially polluted by hexavalent chromium. However, with increasing interest in global environmental issues in recent years, not only laws and regulations that emphasize the conventional work environment and wastewater treatment, but also laws and regulations that emphasize environmental load and environmental harmony are beginning. In addition, with the background of the times when manufacturers are evaluated by their degree of environmental contribution, there is an increasing trend to reduce the use of heavy metals including hexavalent chromium.

Against this background, a number of white rust suppression technologies (chromate-free technologies) for zinc-based plated steel sheets that do not use hexavalent chromium have been proposed. For example, Patent Documents 1 and 2 propose a surface treatment agent containing Al, a phosphoric acid compound, silica, and a water-based organic resin emulsion, and a metal material coated therewith. Patent Document 3 proposes a galvanized steel sheet in which an organic coating layer is formed after an amorphous film is formed by applying and drying a mixed aqueous solution of polyphosphate primary phosphate and metal oxide sol. Has been. Further, in Patent Documents 4 and 5, a composite oxide film layer containing oxide fine particles, phosphoric acid and / or a phosphoric acid compound, and one or more metals selected from Mg, Mn, and Al is used as a lower layer. A steel sheet having an organic film formed thereon is proposed.

There are not a few parts that are heated in the temperature range above the melting point of zinc (about 500 to 600 ° C) among the applications where zinc-based plated steel sheets are applied. For example, in a heat exchanger in an air conditioner outdoor unit, when brazing a copper pipe and an aluminum evaporator, a zinc-based plated steel sheet is placed between the copper pipe and the evaporator to prevent melting of the aluminum by heating using a gas burner. Thus, the flame of the burner is prevented from touching the aluminum directly. When the above-described surface-treated steel sheet according to the prior art is applied to such a use, it is a film mainly composed of an organic resin, so that it is discolored to yellow or brown by thermal decomposition, resulting in poor appearance. For this reason, it is almost impossible to apply the surface-treated steel sheet of the prior art.

In order to solve such problems, a chromate-free technology with excellent heat discoloration has been proposed. For example, Patent Documents 6 and 7 propose an inorganic rich film mainly composed of Mg-phosphate, colloidal silica, and a phosphonic acid compound. Patent Document 8 proposes a two-layer coating in which an inorganic rich coating mainly composed of primary phosphate and colloidal silica is disposed as a lower layer, and a silicate coating and / or a silicon resin is disposed as an upper layer. Patent Document 9 discloses that at least one titanium compound selected from hydrolyzable titanium compounds, low-condensates of hydrolyzable titanium compounds, titanium hydroxide, and low-condensates of titanium hydroxide is hydrogen peroxide. Disclosed is a surface treatment composition containing a titanium-containing aqueous liquid obtained by mixing with water, an organic phosphoric acid, a water-soluble or water-dispersible organic resin, a vanadic acid compound, a zirconium fluoride compound, and a zirconium carbonate compound. .

Japanese Patent Laid-Open No. 11-350157 JP 2000-26980 A JP 2000-129460 A JP 2002-53979 A JP 2002-53980 A JP 2000-79370 A JP 2001-348672 A JP 2004-91826 A Japanese Patent Laid-Open No. 2006-9121

However, the inorganic rich coatings of Patent Documents 6 and 7 have extremely low corrosion resistance levels and are difficult to apply as chromate coating substitutes. On the other hand, the two-layer coating of Patent Document 8 has a corrosion resistance level applicable as a chromate coating substitute, but has a problem in terms of cost because it uses expensive silicate or silicon resin. In addition, the coatings produced by these technologies are subject to a phenomenon of black discoloration (black discoloration) in a humid environment, making it difficult to apply to heat exchangers that are subject to dew condensation, and the storage environment during product transportation. Are also impractical and impractical. Further, the surface treatment composition of Patent Document 9 improves the adhesion resistance when the fluoride contained therein improves the water-resistant adhesion and the corrosion resistance after alkaline degreasing, but has a relatively thick organic resin layer on the upper layer. I will invite you.

In addition, in organic resin-coated steel sheets such as coated steel sheets and laminated steel sheets, the adhesion of the organic resin layer is an important performance, but the conventional phosphating treatment that is performed as a base treatment has a crystalline film. Crystals are destroyed by strict processing, and the adhesion of the organic resin layer tends to be lowered. In particular, in the case of a coated steel sheet or a laminated steel sheet in which the thickness of the organic resin layer is 100 μm or more, the phosphate film is destroyed when the steel sheet is processed, and the organic resin layer is easily peeled off starting from this portion.
In order to deal with such problems, for example, in Patent Documents 3 to 5 listed above, the plating metal on the substrate reacts with the treatment liquid to form a very thin, insoluble phosphate to prevent corrosion resistance and paint adhesion. However, even when such a surface-treated steel sheet is used for an organic resin-coated steel sheet, the adhesion and corrosion resistance when processed are likely to deteriorate. In particular, in the case of an organic resin-coated steel sheet having an organic resin layer with a thickness of 100 μm or more, since the film strength is high, a strong shearing force acts on the interface between the organic resin layer and its base during deformation, and the organic resin layer Peeling easily occurs.

In view of the problems of the prior art as described above, the present applicants have excellent corrosion resistance, heat discoloration resistance and blackening resistance, and excellent adhesion to the organic resin layer formed on the surface treatment film. In particular, Japanese Patent Application No. 2008-335387 has proposed a surface treatment composition capable of obtaining excellent adhesion properties, particularly when a thick organic resin layer having a thickness of 100 μm or more is deformed. This surface treatment composition comprises at least one titanium compound selected from hydrolyzable titanium compounds, low-condensates of hydrolysable titanium compounds, titanium hydroxide, and low-condensates of titanium hydroxide with a hydrogen peroxide solution. A titanium-containing aqueous liquid obtained by mixing with a zirconium carbonate compound, an organic phosphoric acid compound, a metal phosphate, and silicon oxide in a specific ratio.
However, as a result of subsequent studies by the present inventors, the film formed from the above-mentioned surface treatment composition has a relatively brittle nature. It was found that there was a problem that the film was scratched and the corrosion resistance was likely to be lowered.

Accordingly, the object of the present invention is to solve the above-mentioned problems, and does not contain hexavalent chromium at all, and provides excellent corrosion resistance, heat discoloration resistance and blackening resistance, and contact with a metal roll after forming a surface treatment film. Excellent adhesion to the organic resin layer formed on the upper layer of the surface treatment film, particularly a thick organic resin layer having a thickness of 100 μm or more is formed, and is severely processed. An object of the present invention is to provide a surface-treated composition and a surface-treated steel sheet that can obtain excellent adhesion even when added.
Another object of the present invention is to provide an organic resin-coated steel sheet using such a surface-treated steel sheet.

The inventors of the present invention have studied a film composition that can solve the above-described problems, and as a result, on the surface of a metal material (preferably a zinc-based plated steel sheet or an aluminum-based plated steel sheet), a specific titanium-containing aqueous liquid. Forming a surface treatment film by a surface treatment composition in which a zirconium carbonate compound, an organic phosphate compound, a metal phosphate, silicon oxide, and a water-soluble organic resin and / or a water-dispersible organic resin are added in a predetermined ratio. Provides excellent corrosion resistance, heat discoloration resistance and blackening resistance, and excellent scratch resistance when contacting with a metal roll after the surface treatment film is formed. It has been found that a thick organic resin layer having a thickness of 100 μm or more is formed, and excellent adhesion can be obtained even when severe processing is applied.

Since this invention was made | formed based on such knowledge, it makes the following a summary.
[1] Mixing at least one titanium compound selected from hydrolyzable titanium compounds, hydrolyzable titanium compound low-condensates, titanium hydroxide, and titanium hydroxide low-condensates with hydrogen peroxide. 10 to 300 parts by mass of the zirconium carbonate compound (B) and 50 to 200 parts by mass of the organic phosphate compound (C) with respect to 100 parts by mass of the solid content of the resulting titanium-containing aqueous liquid (A), 5 to 20 mass% of metal phosphate (D) in the total solid content of the surface treatment composition, 32 to 40 mass% of silicon oxide (E) in the total solid content of the surface treatment composition, A surface treatment composition comprising 2 to 10 mass% of a water-soluble organic resin and / or a water-dispersible organic resin (F) in a proportion in the total solid content of the surface treatment composition.

[2] The surface treatment composition according to the above [1], wherein the silicon oxide (E) is vapor phase silica produced by a dry method.
[3] The surface treatment composition according to the above [2], wherein the bulk specific gravity of the vapor phase silica is 40 g / L or less.
[4] The surface treatment composition according to any one of the above [1] to [3], wherein the pH is 7 to 12.
[5] The coating amount formed by applying the surface treatment composition of any one of [1] to [4] above to the surface of a zinc-based plated steel sheet or an aluminum-based plated steel sheet and drying is 0.03. A surface-treated steel sheet having a surface-treated film of ˜0.5 g / m ² .
[6] An organic resin-coated steel sheet having an organic resin layer on the surface-treated film of the surface-treated steel sheet of [5].

Since the surface treatment film formed by the surface treatment composition of the present invention has a high level of barrier properties by being composed of a specific inorganic component, it has excellent corrosion resistance and blackening resistance comparable to a chromate film, In addition, it has excellent heat discoloration that hardly causes coloration or discoloration by heating. Furthermore, the scratch resistance when a metal roll or the like comes into contact after the surface treatment film is formed, and an organic resin layer, particularly a thick organic resin layer having a thickness of 100 μm or more is formed on the surface treatment film, Excellent adhesion is obtained even when harsh processing is applied.
In addition, the surface-treated steel sheet and the organic resin-coated steel sheet of the present invention are excellent in corrosion resistance, blackening resistance, heat discoloration resistance and scratch resistance, and are thick enough to have adhesion of the organic resin layer, particularly 100 μm or more. Excellent adhesion of organic resin layer.

The surface treatment composition of the present invention comprises a titanium-containing aqueous liquid (A), a zirconium carbonate compound (B), an organic phosphate compound (C), a metal phosphate (D), silicon oxide (E), and a water-soluble organic resin. And / or a water-dispersible organic resin (F). This surface treatment composition does not contain hexavalent chromium (except for hexavalent chromium as an inevitable impurity).
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 group having 1 to 5 carbon atoms). Tetraalkoxy titanium is preferred. Examples of the alkyl group having 1 to 5 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a sec-butyl group, and a tert-butyl group. Can be mentioned.
Typical examples of the hydrolyzable titanium compound having a group capable of forming a salt with titanium as a hydrolyzable group include titanium chloride and titanium sulfate.

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

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

As the titanium-containing aqueous liquid (A), any conventionally known liquid can be used without particular limitation as long as it is an aqueous liquid containing titanium obtained by mixing the above-described titanium compound and hydrogen peroxide solution. Specifically, the following can be mentioned.
(I) A titanyl ion hydrogen peroxide complex or an aqueous solution of titanic acid (peroxotitanium hydrate) obtained by adding hydrogen peroxide to a hydrous titanium oxide gel or sol (JP 63-35419 A, 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 this titania film forming liquid is obtained, titanium hydroxide gel called ortho titanic 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 a peroxotitanium hydrate, and then the solution obtained by adding a basic substance is allowed to stand or be heated. A titanium oxide forming solution obtained by forming a precipitate of a titanium hydrate polymer, and then removing hydrogen and other dissolved components derived from at least a titanium-containing raw material solution (Japanese Patent Application Laid-Open 2000-247638, JP-A-2000-247639).

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

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

The surface treatment composition (H) containing the titanium-containing aqueous liquid (A) using the hydrolyzable titanium compound a is applied to the surface of the plated steel plate and dried (for example, heat-dried at a low temperature), thereby adhering to itself. A dense titanium oxide-containing film (surface treatment film) having excellent properties can be formed.
The heating temperature of the steel sheet after the application of the surface treatment composition (H) is, for example, preferably 200 ° C. or lower, particularly preferably 150 ° C. or lower. Amorphous) titanium oxide-containing film can be formed.
In addition, 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), the crystal can be obtained by simply applying the surface treatment composition (H). 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), (iii) Titanium oxide aggregates obtained by hydrolyzing or neutralizing titanium halide solutions such as titanium tetrachloride, etc. An amorphous titania sol dispersed in water, or a sol in which the titanium oxide aggregates are calcined to form anatase-type titanium fine particles and this is dispersed in water can be used.

In the firing of the amorphous titania, the amorphous titania can be converted to anatase titania by firing at a temperature at least higher than the crystallization temperature of anatase, for example, at a temperature of 400 ° C. to 500 ° C. or higher. Examples of the aqueous sol of titanium oxide include, for example, TKS-201 (trade name, manufactured by Teika, anatase crystal form, average particle diameter 6 nm), TA-15 (trade name, manufactured by Nissan Chemical Co., anatase crystal form). STS-11 (trade name, manufactured by Ishihara Sangyo Co., Ltd., anatase crystal form).
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 / The range of 99 to 99/1, preferably about 10/90 to 90/10 is appropriate. If the mass ratio x / y is 1/99 or more, the effect of adding the titanium oxide sol is sufficiently obtained in terms of stability, photoreactivity, and the like, and if it is 99/1 or less, excellent film formation is achieved. It is preferable because of its property.

The titanium-containing aqueous liquid (A1) can be obtained by reacting the hydrolyzable titanium compound a with hydrogen peroxide at a reaction temperature of 1 to 70 ° C. for about 10 minutes to 20 hours in the presence of a titanium oxide sol.
The production form and characteristics of the titanium-containing aqueous liquid (A1) are the same as those of the titanium-containing aqueous liquid (A) using the hydrolyzable titanium compound a described above, but in particular, by using a titanium oxide sol. , It is possible to suppress a partial condensation reaction during the synthesis to increase the viscosity. The reason is considered to be that the condensation reaction product is adsorbed on the surface of the titanium oxide sol, and polymerization in a solution state is suppressed.
Further, when the titanium-containing aqueous liquid (A1) is heated or autoclaved at 80 ° C. or higher, a titanium oxide dispersion containing ultrafine particles of crystallized titanium oxide is obtained. The titanium-containing aqueous liquid (A) using the hydrolyzable titanium compound a described above also describes the temperature conditions for obtaining this titanium oxide dispersion, the particle diameter of the crystallized titanium oxide ultrafine particles, the appearance of the dispersion, etc. It is the same. Such a titanium oxide dispersion can also be used as the titanium-containing aqueous liquid (A1).

Similar to the titanium-containing aqueous liquid (A) using the hydrolyzable titanium compound a described above, the surface treatment composition (G) containing the titanium-containing aqueous liquid (A1) is applied to the surface of the plated steel sheet and dried (for example, By heating and drying at a low temperature, it is possible to form a dense titanium oxide-containing film (surface-treated film) having excellent adhesion by itself.
The heating temperature of the steel sheet after the application of the surface treatment composition (G) is, for example, 200 ° C. or less, particularly preferably 150 ° C. or less. By heating and drying at such a temperature, anatase-type oxidation containing some hydroxyl groups. A titanium-containing 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, more preferably 1 to 20 parts by mass in terms of hydrogen peroxide with respect to 10 parts by mass. If the blending ratio of hydrogen peroxide water is 0.1 parts by mass or more in terms of hydrogen peroxide, chelate formation is sufficient so that no cloudy precipitation occurs. On the other hand, if it is 100 parts by mass or less, unreacted This is preferable because no hydrogen peroxide remains, and no active oxygen is released during storage.
The hydrogen peroxide concentration in the hydrogen peroxide solution is not particularly limited, but it is preferably about 3 to 30 mass% from the viewpoint of ease of handling and the solid content of the produced liquid related to the coating workability.

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

The surface treatment composition of the present invention further improves the corrosion resistance by adding the zirconium carbonate compound (B) to the titanium-containing aqueous liquid (A), and an organic resin layer (an organic resin layer formed by lamination or coating). The corrosion resistance after coating with the organic resin layer is significantly improved. In addition, the organophosphate compound (C) increases the reactivity with the steel sheet to improve the corrosion resistance, and also improves the storage stability of the surface treatment composition. Furthermore, by adding metal phosphate (D) and silicon oxide (E), an organic resin layer formed as an upper layer, particularly a thick organic resin layer having a thickness of 100 μm or more (for example, formed by lamination). The adhesion of the organic resin layer) during deformation of the steel sheet is improved. Furthermore, by adding a water-soluble organic resin and / or water-dispersible organic resin (F), the scratch resistance of the surface treatment film is improved, and even when roll contact occurs after the surface treatment film is formed, excellent corrosion resistance is achieved. It expresses.

As the zirconium carbonate compound (B), ammonium zirconium carbonate, zirconium oxycarbonate and the like are suitable, and improvement of corrosion resistance can be achieved by using at least one of these. The compounding amount of the zirconium carbonate compound (B) is 10 to 300 parts by mass, preferably 50 to 100 parts by mass with respect to 100 parts by mass of the solid content of the titanium-containing aqueous liquid (A). When the blending amount of the zirconium carbonate compound (B) 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 effect of improving the corrosion resistance is small. Tend to deteriorate.

Examples of the organic phosphoric acid compound (C) include hydroxyl groups such as 1-hydroxymethane-1,1-diphosphonic acid, 1-hydroxyethane-1,1-diphosphonic acid, and 1-hydroxypropane-1,1-diphosphonic acid. Group-containing organic phosphorous acid; carboxyl group-containing organic phosphorous acid such as 2-hydroxyphosphonoacetic acid and 2-phosphonobutane-1,2,4-tricarboxylic acid, and salts thereof are preferred. 1 type (s) or 2 or more types can be used.

The organic phosphoric acid compound (C) has the effect of improving the corrosion resistance and the storage stability of the titanium-containing aqueous liquid (A). Among them, 1-hydroxyethane-1,1-diphosphonic acid is particularly effective. Therefore, it is particularly preferable to use this.
The compounding amount of the organic phosphoric acid compound (C) is 50 to 200 parts by mass, particularly 70 to 150 parts by mass with respect to 100 parts by mass of the solid content of the titanium-containing aqueous liquid (A). It is preferable from the point. When the compounding amount of the organic phosphoric acid compound (C) is less than 50 parts by mass with respect to 100 parts by mass of the solid content of the titanium-containing aqueous liquid (A), the storage stability of the surface treatment composition is inferior and the corrosion resistance is reduced. It is done. On the other hand, when it exceeds 200 mass parts, water-resistant adhesiveness is inferior.

Metal phosphate (D) and silicon oxide (E) are blended in order to improve adhesion to an organic resin layer formed as an upper layer by laminating or the like, particularly a thick organic resin layer having a thickness of 100 μm or more. It is something to be made. Examples of silicon oxide (E) include amorphous silica such as liquid phase silica produced by a liquid phase reaction method and gas phase silica produced by a dry method, and one or more of these are used. be able to. Specifically, as liquid phase silica, SNOWTEX (registered trademark) O, N, 20, 30, 40, C, S manufactured by Nissan Chemical Industries, Ltd., as gas phase silica, Nippon Aerosil Co., Ltd. AEROSIL (registered trademark) 130, 200, 200V, 200CF, 300, 300CF, etc. manufactured by the company can be used.
Among these, vapor-phase silica produced by a dry method is very preferable from the viewpoint of adhesion to the organic resin layer, and good performance can be obtained.

Also, there are no special restrictions on the type of metal phosphate (D), but among them, aluminum salts, magnesium salts, and manganese salts are effective. In particular, in the case of an aluminum salt, there is an advantage that the solubility of the phosphate is lowered and the effect in a humid environment is sustained. 1 type (s) or 2 or more types can be used for said metal phosphate. Further, as the metal phosphate (D), it is preferable to apply a commercially available aqueous solution in which the phosphoric acid / metal cation component ratio is rich in phosphoric acid in advance so that it can exist as an aqueous solution.

In order to add (compound) the metal phosphate (D) and the silicon oxide (E) in the surface treatment composition, the metal phosphate (D) and the silicon oxide (E) are mixed in advance, It is preferable to add in the form of this mixture. More excellent adhesion and corrosion resistance can be obtained when added in a premixed state than when added separately. Although this reason is not necessarily clear, it is thought that it is because the cohesive force of the film obtained by the surface treatment composition is increased by the effect of the phosphoric acid component. Moreover, the storage stability of the surface treatment composition is improved by mixing by this method.
When silica (gas phase silica) produced by a dry method is used as silicon oxide (E), the metal phosphate aqueous solution is obtained by adding the gas phase silica to the metal phosphate aqueous solution and stirring vigorously. A silicon oxide dispersion liquid in which vapor phase silica is dispersed may be prepared in advance and mixed with other components. Alternatively, the surface treatment composition may be prepared by vigorously stirring the vapor phase silica and the metal phosphate aqueous solution together with other compounding components and water.

Further, when vapor phase silica is dispersed in the surface treatment composition with a sand mill or the like, aggregation occurs in about one week to several weeks, and a precipitate is generated. Although the detailed mechanism is not clear, it has been found that it is effective to use gas phase silica having a low bulk specific gravity in order to prevent such aggregation and improve storage stability (chemical solution stability). It was. Specifically, it is preferable to use gas phase silica having a bulk specific gravity of 40 g / L or less. The bulk specific gravity of the vapor phase silica can be adjusted by controlling the deaeration conditions after the production by the dry method, whereby a vapor phase silica having a small bulk specific gravity can be obtained.

The adhesion of the organic resin layer is improved by blending the metal phosphate (D) and the silicon oxide (E). The surface polarity of the surface treatment film is changed by blending the silicon oxide and the metal phosphate. It is thought that this is because it acts on the adhesiveness advantageously. Since silicon oxide increases the polarity, it has the effect of increasing the adhesion with the resin layer and the adhesive layer when the organic resin layer is directly applied to the upper layer or when the organic resin film is brought into close contact with the adhesive. On the other hand, if the polarity is too high, it becomes easy to take in moisture in a humid environment, which is disadvantageous for swelling. On the other hand, by blending nonpolar phosphoric acid (metal phosphate), it is possible to realize an appropriate surface polarity that can achieve both adhesion and stability when wet. Furthermore, secondary aggregation of silicon oxide forms surface irregularities on the order of submicrons, and the formation of such surface irregularities increases the effective area at the adhesion interface, thus effectively acting on adhesion. It is considered a thing. Although the influence on the texture due to the incorporation of the metal phosphate is not sufficiently clear, it is considered that the texture is affected by acting on the secondary aggregation of silicon oxide.

The compounding amount of the metal phosphate (D) is 5 to 20 mass% as a ratio in the total solid content of the surface treatment composition, and the compounding amount of silicon oxide (E) is in the total solid content of the surface treatment composition. The ratio is 32 to 40 mass%.
When the blending amount of the metal phosphate (D) is less than 5 mass% in the ratio of the total solid content of the surface treatment composition, the effect is not exhibited and the adhesion to the steel sheet becomes insufficient. On the other hand, when it exceeds 20 mass% and it adds excessively, it becomes a factor which deteriorates performance, such as blackening at the time of storage until it coat | covers an organic resin layer.

If the blending amount of silicon oxide (E) is less than 32 mass% in the total solid content of the surface treatment composition, formation of irregularities on the order of submicron is insufficient, and the upper organic resin layer and Sufficient adhesion cannot be obtained. On the other hand, if it exceeds 40 mass%, good adhesion can be obtained, but the surface treatment film becomes brittle, so the film is scratched by roll contact etc., and of course the bare corrosion resistance as well as the scratched part after coating with organic resin Corrosion progresses and blistering occurs.

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

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

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

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

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

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

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

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

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

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

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

The blending amount of the water-soluble organic resin and / or the water-dispersible organic resin (F) is 2 to 10 mass% as a ratio in the total solid content of the surface treatment composition. If the blending amount of the water-soluble organic resin and / or water-dispersible organic resin (F) is less than 2 mass% in the total solid content of the surface treatment composition, the brittleness of the surface treatment film cannot be improved and the surface treatment is performed. The film is scratched by contact with the roll after the film is formed, and the corrosion starts from the scratched part after the organic resin coating as well as the bare corrosion resistance. On the other hand, if it exceeds 10 mass%, the heat discoloration and post-processing adhesion will be reduced.
The pH of the surface treatment composition is preferably adjusted to 7-12. If the pH is less than 7 or more than 12, aggregation of the surface treatment composition occurs with time, and a film cannot be formed.

If necessary, the surface treatment composition of the present invention may further include, for example, an etching agent such as a silane coupling agent, resin fine particles, and an inorganic phosphate compound, a heavy metal compound other than the components specified by the present invention, a thickener, A surfactant, a lubricity-imparting agent (polyethylene wax, fluorine-based wax, carnauba wax, etc.), a rust inhibitor, a color pigment, an extender pigment, a rust preventive pigment, and a dye can be contained. In particular, in order to improve the adhesion with the organic resin layer, it is preferable to contain a silane coupling agent.
Moreover, the surface treatment composition of this invention can be diluted with hydrophilic solvents, such as methanol, ethanol, isopropyl alcohol, an ethylene glycol type solvent, a propylene glycol type solvent, for example as needed, and can be used.
The surface treatment composition of the present invention preferably has a solid content of about 2 to 10 mass% from the viewpoint of storage stability and stability during coating.
The surface treatment composition of the present invention can be used as a surface treatment agent for various metal materials, but is particularly suitable as a surface treatment agent for zinc-based plated steel sheets and aluminum-based plated steel sheets described later.

The surface-treated steel sheet of the present invention has a surface-treated composition as described above, that is, a titanium-containing aqueous liquid (A), a zirconium carbonate compound (B), and an organic phosphate compound on the surface of a zinc-based plated steel sheet or an aluminum-based plated steel sheet. Formed by applying and drying a surface treatment composition containing (C), metal phosphate (D), silicon oxide (E), and water-soluble organic resin or / and water-dispersible organic resin (F) And having a surface-treated film having a predetermined coating amount. This surface-treated film does not contain hexavalent chromium (except for hexavalent chromium as an inevitable impurity).
Further, the titanium-containing aqueous liquid (A) and the surface treatment composition may further contain other additive components as mentioned above, if necessary.

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 sheets (for example, Zn-5 mass% Al alloy-plated steel sheets, Zn-55 mass% Al alloy-plated steel sheets), Zn-Mg alloy-plated steel sheets, Zn-Al-Mg alloy-plated steel sheets, and plating of these plated steel sheets Zinc-based composite plated steel sheet (for example, Zn-SiO2 dispersion plated steel sheet) in which metal oxide, polymer, etc. are dispersed in the coating Etc. can be used. Moreover, the multilayer plating steel plate which plated two or more layers of the same kind or different kind among the above plating can also be used.

Moreover, as an aluminum system plated steel plate used as the base of the surface treatment steel plate of this invention, an aluminum plating steel plate, an Al-Si alloy plating steel plate, etc. can be used.
Moreover, as a plated steel plate, the steel plate surface may be previously plated with lightness such as Ni, and various plating as described above 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.
In addition, when the surface treatment film is formed on the surface of the plating film, alkali degreasing, solvent degreasing, surface conditioning treatment (alkaline surface conditioning) is performed on the surface of the plating film as necessary in order to prevent film defects and unevenness from occurring. Treatment or acidic surface conditioning treatment) can be performed.

In addition, for the purpose of preventing blackening in the usage environment (a kind of oxidation phenomenon on the plating surface), an iron group metal ion (one or more of Ni ion, Co ion, Fe ion) is previously applied to the plating surface as necessary. Surface adjustment treatment with an acidic or alkaline aqueous solution containing can also be performed.
When using an electrogalvanized steel sheet as the base steel sheet, iron group metal ions (one or more of Ni ions, Co ions, Fe ions) are added to the electroplating bath for the purpose of preventing blackening, and the plating film These metals can be contained in an amount of 1 mass ppm or more. In this case, there is no particular limitation on the upper limit of the iron group metal concentration in the plating film.
The adhesion amount of the surface treatment film formed by the surface treatment composition is 0.03 to 0.5 g / m ² . If the coating amount is less than 0.03 g / m ² , the corrosion resistance is inferior. On the other hand, if it exceeds 0.5 g / m ² , the coating tends to break, and the adhesion during severe processing after coating with an organic resin is reduced.

In order to produce the surface-treated steel sheet of the present invention, the surface treatment composition as described above, that is, the titanium-containing aqueous liquid (A), the zirconium carbonate compound (B), on the surface of the zinc-based plated steel sheet or the aluminum-based plated steel sheet, Application of a surface treatment composition (treatment liquid) containing an organic phosphate compound (C), metal phosphate (D), silicon oxide (E) and a water-soluble organic resin or / and a water-dispersible organic resin (F) Then, it is dried without washing with water.
Further, the titanium-containing aqueous liquid (A) and the surface treatment composition may further contain other additive components as mentioned above, if necessary.

The means for applying the surface treatment composition (treatment liquid) is optional, for example, spray + roll squeezing, roll coater, etc. Also, the drying method after application is also, for example, a hot air method, induction heating method, electric furnace method, etc. Is optional.
The drying temperature (steel plate temperature) of the applied surface treatment composition (treatment liquid) is preferably about 60 to 200 ° C. When the drying temperature is 60 ° C. or higher, film formation is sufficient and a film having excellent corrosion resistance and the like is obtained. On the other hand, if the drying temperature is 200 ° C. or less, cracks are not generated in the film due to heat, so that a sufficient effect of improving corrosion resistance is obtained. A more preferable drying temperature is 60 to 140 ° C., and a further preferable temperature is 60 to 100 ° C.

The organic resin-coated steel sheet of the present invention is obtained by forming an organic resin layer on the surface-treated film of the surface-treated steel sheet as described above. The method for forming the organic resin layer is arbitrary, and for example, a method of applying and drying a coating composition, a method of laminating an organic resin film, and the like can be applied.
Moreover, since the surface treatment film of the present invention is particularly excellent in adhesion of a thick organic resin layer having a thickness of 100 μm or more, the organic resin-coated steel sheet of the present invention has an organic resin layer thickness of 100 μm or more. Is particularly useful.
The organic resin layer may contain various additives including non-chromium rust preventive additives, solid lubricants, color pigments and the like.

The titanium-containing aqueous liquid (A) and components (B) to (F) used in the surface treatment composition are shown below. [Production of titanium-containing aqueous liquid (A)]
Production Example 1 (Titanium-containing aqueous liquid T1)
Ammonia water (1: 9 = ammonia: water mass ratio) was added dropwise to a solution of 5 cc of titanium tetrachloride 60 mass% in 500 cc of distilled water to precipitate a low condensation product of titanium hydroxide. After washing with distilled water, 10 cc of a 30 mass% hydrogen peroxide solution was added and mixed to obtain a yellow translucent viscous titanium-containing aqueous liquid T1 containing titanium.

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

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

Production Example 6 (Titanium-containing aqueous liquid T6)
The titanium-containing aqueous liquid T3 produced in Production Example 3 was further heat-treated at 95 ° C. for 6 hours to obtain a white yellow translucent titanium-containing aqueous liquid T6.
Production Example 7 (Titanium-containing aqueous liquid T7)
A mixture of 10 parts by mass of tetraiso-propoxytitanium and 10 parts by mass of iso-propanol was mixed with 5 parts by mass (solid content) of “TKS-203” (trade name, manufactured by Teika Co., Ltd.), 10 mass% 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 T7.

[Zirconium compound (B)]
B1: Ammonium zirconium carbonate B2: Zirconium oxycarbonate B3: Zircon ammonium fluoride [Organic phosphate compound (C)]
C1: 1-hydroxymethane-1,1-diphosphonic acid C2: 1-hydroxyethane-1,1-diphosphonic acid

[Mixture of metal phosphate (D) and silicon oxide (E)]
Silicon oxide (E) is added to the aqueous solution of metal phosphate (D) at the solid content blending ratio shown in Table 3, Table 5, Table 7, and Table 9 and stirred vigorously, and silicon oxide is added to the metal phosphate aqueous solution. A dispersed mixture was obtained. In Tables 7 and 8, No. 77 comparative examples contain only silicon oxide E4.
・ Metal phosphate (D)
D1: primary aluminum phosphate D2: primary magnesium phosphate D3: primary manganese phosphate / silicon oxide (E)
E1: Aerosil 300 (trade name, manufactured by Nippon Aerosil Co., Ltd., vapor phase silica, bulk specific gravity; 50 g / L)
E2: Aerosil 200 (trade name, manufactured by Nippon Aerosil Co., Ltd., vapor phase silica, bulk specific gravity; 35 g / L)
E3: Snowtex O (trade name, manufactured by Nissan Chemical Industries, colloidal silica)
E4: Aerosil 300CF (trade name, manufactured by Nippon Aerosil Co., Ltd., vapor phase silica, bulk specific gravity; 35 g / L)

[Water-soluble or water-dispersible organic resin (F)]
Of the water-soluble or water-dispersible organic resins, water-dispersible acrylic resins F1 to F5 were produced according to Production Examples 8 to 12 shown below, and commercially available products were used for F6 to F13. In the following production examples, “part” and “%” are based on mass.
Production Example 8 (Water-dispersible acrylic resin F1)
265 parts deionized water, 9 parts Aqualon RN-50 (Note 1), Aqualon RN-2025 (Note 2) 87 in a 2-liter four-necked flask equipped with a reflux condenser, stirrer, thermometer, and dropping funnel 5% (28.9 parts) of a pre-emulsion obtained by forcibly emulsifying monomer mixture liquid 1 (first stage) having the following composition was added, and the temperature was raised after nitrogen substitution.
<< Monomer mixture 1 >>
Deionized water 166.5 parts Aqualon RN-50 6.6 parts Aqualon RN-2025 53 parts Styrene 35 parts Methyl methacrylate 163.5 parts 2-Ethylhexyl acrylate 105 parts 2-Hydroxyethyl methacrylate 5 parts Methacrylic acid 3 parts Acrylonitrile 38. 5 parts Tertiary decanethiol 1 part When the temperature reaches 55 ° C or higher, 5% (4.43 parts) of an oxidizing agent aqueous solution obtained by dissolving 5 parts of perbutyl H (Note 3) in 83.5 parts of deionized water and sodium 5% (4.3 parts) of a reducing agent aqueous solution prepared by dissolving 2.5 parts of formaldehyde sulfoxylate in 83.5 parts of deionized water was added, and the temperature was further raised and maintained at 60 ° C. 15 minutes after the addition, the remaining pre-emulsion was added dropwise over 1.5 hours, the oxidizing agent aqueous solution for 3.5 hours, and the reducing agent aqueous solution over 3.5 hours. While the dropping of the oxidizing agent aqueous solution and the reducing agent aqueous solution was continued, the monomer mixed solution 2 (second stage) having the following composition was dropped over 1 hour from the end of dropping of the first stage pre-emulsion.
<< Monomer mixture 2 >>
Styrene 15 parts Methyl methacrylate 84.5 parts 2-Ethylhexyl acrylate 22.5 parts 2-hydroxyethyl methacrylate 4.25 parts Methacrylic acid 6 parts Acrylonitrile 15 parts γ-Methacryloxypropyltrimethoxysilane 2.75 parts The temperature is kept at 60 ° C. for 1 hour, and then the temperature is lowered to 40 ° C. or less. 3.35 parts of 25% aqueous ammonia, 0.35 parts of Suraoff EX (Note 4), 2,2,4-trimethyl-1 , 3-pentanediol monoisobutyrate 83.5 parts was added to obtain a water-dispersible acrylic resin F1 having a pH of 8.0 and a non-volatile content of 31%.
(Note 1) Aqualon RN-50: trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., nonionic emulsifier, solid content 60%
(Note 2) Aqualon RN-2025: trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., nonionic emulsifier, solid content 25%
(Note 3) Perbutyl H: trade name, manufactured by NOF Corporation, t-butylhydroxyperoxide, 69% active ingredient
(Note 4) Sura-off EX: trade name, manufactured by Nippon Enviro Chemicals, Inc., preservative

・ Production examples 9 to 12 (water-dispersible acrylic resins F2 to F5)
In Production Example 8, water-dispersible acrylic resins F2 to F5 were obtained in the same manner as in Production Example 8, except that the monomer composition of the first and second stages was changed to the blending ratio shown in Table 2.
Table 2 also shows the characteristic values of each water-dispersible acrylic resin.

F6: Superflex E-2500 (trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., aqueous polyurethane resin)
F7: Superflex 150 (trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., water-based polyurethane resin)
F8: Superflex 420 (trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., water-based polyurethane resin)
F9: Superflex 300 (trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., water-based polyurethane resin)
F10: Bironal MD-1100 (trade name, manufactured by Toyobo Co., Ltd., water-based polyester resin)
F11: Adeka Resin EM-0718 (trade name, manufactured by ADEKA, water-based epoxy resin)
F12: MODEPICS 303 (trade name, manufactured by Arakawa Chemical Industries, Ltd., water-based epoxy resin)
F13: Watersol S-370 (trade name, manufactured by Dainippon Ink and Chemicals, water-based epoxy resin)

As the base steel plate of the surface-treated steel plate, the plated steel plate shown in Table 1 was used.
Surface treatment composition in which components (B) to (F) and distilled water are appropriately blended and mixed with the titanium-containing aqueous liquid (A) described above, and the solid content is adjusted to 2 to 10 mass% and the pH is adjusted to 8. The product was applied to the surface of the plated steel sheet and dried after 5 seconds so as to reach a predetermined drying temperature (maximum plate temperature) to prepare a surface-treated steel sheet. The surface-treated steel sheet thus obtained is wound with a paper roll wrapped around a rubber roll (48 mmφ × 205 mm) and scratched on the surface of the coating once without rotating the roll with a load of 690 g (including the roll's own weight). It processed and it was set as the test material 1. In addition, as described in Table 5 and Table 6, The comparative example 46 does not perform the scratching process.

These test materials 1 were evaluated for heat discoloration resistance, water adhesion resistance, corrosion resistance, and blackening resistance by the following test methods (1) to (4).
Furthermore, after applying a general adhesive for a polyvinyl chloride film to the test material 1 so that the dry film thickness becomes 3 μm, the furnace temperature is heated in a heating furnace having a temperature of 100 ° C., and then a polyvinyl chloride film having a film thickness of 250 μm. Is pressed against the surface of the test material with a roll so that the steel plate temperature becomes 230 ° C., and a polyvinyl chloride film (organic resin layer) is adhered by thermocompression bonding, and an organic resin-coated steel plate (this is “test material 2”). And). With respect to the specimen 2 thus produced, the post-processing adhesion and corrosion resistance were evaluated by the following test methods (5) and (6).
Furthermore, the storage stability of the surface treatment composition was evaluated by the following test methods (7) and (8).
The above results are shown in Tables 3 to 10 together with the composition of the surface treatment composition applied to each specimen and the coating conditions.

(1) Heat-resistant discoloration The specimen 1 was heated to a plate temperature of 500 ° C. in 30 seconds in an infrared image furnace, held for 30 seconds, and then visually observed on the surface appearance when naturally cooled to room temperature. The evaluation criteria are as follows.
○: No color change Δ: Color change to pale yellow ×: Color change from yellow to brown (2) Water-resistant adhesion Surface appearance when 1 mL of pure water is dropped on the test material 1 and dried in an oven at 100 ° C. for 10 minutes. Was visually observed. The evaluation criteria are as follows.
◎: No change ○: Almost no change △: Only the outline of the dropping part is observed ×: The whole dropping part is discolored

(3) Corrosion resistance Using a test piece of 50 mm × 100 mm cut out from the test material 1, the end and the back of the test piece are sealed, a salt spray test of JIS-Z-2371-2000 is performed, and white rust is obtained. The test time at which the generation area ratio was 5% was measured. The evaluation criteria are as follows.
◎: 36 hours or more ○: 24 hours or more, less than 36 hours Δ: 12 hours or more, less than 24 hours ×: Less than 12 hours (4) Blackening resistance The test material 1 is controlled to an atmosphere of 80 ° C. and 95% relative humidity. The change in whiteness (L value) when left in a constant temperature and humidity chamber for 24 hours was calculated as ΔL (L value after test−L value before test). The evaluation criteria are as follows.
○: ΔL ≧ −5.0
Δ: −5.0> ΔL ≧ −10.0
×: −10.0> ΔL

(5) Adhesion after processing (peeling strength after processing)
Using a test piece of 30 mm × 120 mm cut out from the specimen 2, draw a double line at 50 mm intervals perpendicular to the length direction at the center of the test piece in the length direction. Both ends in the vertical direction were grasped with a clamp of a tensile tester, and stretched in a uniaxial direction until the distance between the two lines reached 60 mm. Using the stretched test piece as a sample, the organic resin layer between the spread two wires was provided with a cut reaching the steel plate so as to have a width of 20 mm. One end of the organic resin layer provided with this incision is forcibly peeled off, the end of the peeled organic resin layer is gripped by one clamp of a tensile tester, a steel plate is gripped by the other clamp of the tensile tester, and the peeling speed is 50 mm. A peel test was performed under the conditions of / min. In this peeling test, the organic resin layer peeled in the direction of 180 degrees (opposite direction) from the steel sheet surface, and the maximum strength (= peeling strength) at the time of peeling was measured. The higher the peel strength, the harder the organic resin layer is peeled from the metal plate, and the better the adhesion after bending or drawing. Based on the measured peel strength, the post-processing adhesion was evaluated according to the following criteria.
A: Peel strength is 40 N / 20 mm width or more B: Peel strength is 30 N / 20 mm width or more and less than 40 N / 20 mm width X: Peel strength is less than 30 N / 20 mm width

(6) Corrosion resistance (scratch resistance)
A 50 mm × 100 mm test piece cut out from the test material 2 was used, a cross cut was made on the surface of the test piece, and a salt spray test was conducted for 1000 hours in accordance with the provisions of JIS-Z-2371-2000. The one-sided corrosion width from the crosscut was measured. The evaluation criteria are as follows.
A: The average corrosion width from the cut portion is less than 5 mm. O: The average corrosion width from the cut portion is 5 mm or more and less than 10 mm. X: The average corrosion width from the cut portion is 10 mm or more. The film formed on the surface of the surface-treated steel sheet. If the scratch resistance is inferior, the coating is scraped off and a large number of scratches reaching the plated surface are formed. Since there is no film in the scratched part, the adhesion with the organic resin layer is poor, and water easily enters. Therefore, salt water that has entered from the cross cut portion penetrates into the scratch portion, and corrosion progresses. As a result, when the scratch resistance is inferior, the corrosion width from the cross cut portion increases. Therefore, the evaluation of the one-sided average corrosion width from the cross cut is an evaluation of scratch resistance.

(7) Storage stability (I)
The surface treatment composition having a solid content of 8 mass% was aged at 40 ° C. for 2 weeks, and the precipitation state and viscosity of the solid content were visually evaluated. The evaluation criteria are as follows.
◎: No solid content precipitation and no change in viscosity ○: Slight solid content precipitation or small viscosity change △: Many solid content precipitations or large viscosity change ×: Many solid content precipitations Large change in viscosity (8) Storage stability (II)
The surface treatment composition having a solid content of 8 mass% was maintained at 30 ° C., and the solid precipitation state was visually evaluated every week. The evaluation criteria are as follows.
◎: No precipitation after 4 weeks ○: Precipitation occurs after 4 weeks △: Precipitation occurs after 2 to 3 weeks ×: Precipitation occurs after 1 week

In Table 3, Table 5, Table 7, and Table 9, * 1 to * 9 indicate the following contents.
* 1 Plated steel plate No. 1-No. 9
* 2 Titanium-containing aqueous liquids T1 to T7 described in the main text of the specification
* 3 Zirconium compounds B1 to B3 described in the specification text
* 4 Organophosphate compounds C1, C2 described in the main text of the specification
* 5 Metal phosphates D1 to D3 described in the specification text
* 6 Silicon oxides E1 to E4 described in the specification text
* 7 Water-soluble or water-dispersible organic resins F1 to F13 described in the main text of the specification
* 8 Solid content mass (g) in 1 liter of surface treatment composition (aqueous treatment liquid)
* 9 Ratio of the surface treatment composition (aqueous treatment liquid) in the total solid content (mass%)

Claims (6)

1. Titanium obtained by mixing at least one titanium compound selected from hydrolyzable titanium compounds, low-condensates of hydrolyzable titanium compounds, titanium hydroxide, and low-condensates of titanium hydroxide with hydrogen peroxide water 10 to 300 parts by mass of the zirconium carbonate compound (B) and 50 to 200 parts by mass of the organic phosphoric acid compound (C) with respect to 100 parts by mass of the solid content of the aqueous solution (A). 5 to 20 mass% of salt (D) in the total solid content of the surface treatment composition, and 32 to 40 mass% of silicon oxide (E) in the total solid content of the surface treatment composition, water-soluble organic A surface treatment composition comprising 2 to 10 mass% of a resin and / or a water-dispersible organic resin (F) in a proportion in the total solid content of the surface treatment composition.
2. The surface treatment composition according to claim 1, wherein the silicon oxide (E) is vapor phase silica produced by a dry method.
3. The surface treatment composition according to claim 2, wherein the bulk specific gravity of the vapor phase silica is 40 g / L or less.
4. The surface treatment composition according to any one of claims 1 to 3, wherein the pH is 7 to 12.
5. A coating amount formed by applying the surface treatment composition according to any one of claims 1 to 4 to the surface of a zinc-based plated steel sheet or an aluminum-based plated steel sheet and drying the film is 0.03-0. A surface-treated steel sheet having a surface-treated film of 0.5 g / m ² .
6. An organic resin-coated steel sheet comprising an organic resin layer on the surface-treated film of the surface-treated steel sheet according to claim 5.