JP2008000910A - Highly anticorrosive surface treated steel sheet and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a chromium free surface, treated excellent anticorrosive steel sheet. <P>SOLUTION: A surface treatment film is formed on the surface of a galvanized sheet or the like using a composition, which contains an aqueous dispersant of an epoxy resin, which is obtained by adding a hydrazine derivative having active hydrogen to a specific polyalkylene glycol modified epoxy resin, a silane coupling agent and phosphoric acid or a hexafluorometal acid, and an upper layer film is formed on the surface of the surface treatment film using a composition contains an epoxy group-containing resin, a urethane resin and an organometal compound. The especially excellent anticorrosive of a processed part is obtained by the composite action of a specific surface treatment film being a lower layer film and the upper layer film containing the specific organic resin and the organometal compound. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a highly corrosion-resistant surface-treated steel sheet that is particularly suitable for automobile inner and outer plates, and relates to an environment-adaptive surface-treated steel sheet that does not contain chromium at all during the production of the surface-treated steel sheet and the surface-treated film, and a method for producing the same. It is.

  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 galvanized steel sheets or aluminum galvanized 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 has excellent 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 not released into nature. Since the elution of chromium from the chromate film can be made almost zero by the sealing action of the organic film, the environment and the human body are not substantially contaminated by hexavalent chromium. However, due to recent global environmental problems, there is a growing trend to voluntarily reduce the use of heavy metals including hexavalent chromium. In addition, in order not to pollute the environment when the shredder dust of discarded products is dumped, there has been a movement to minimize or reduce the amount of heavy metals contained in the product.

  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.

Specifically, the following methods can be listed as conventional techniques.
(1) A method of forming a film by immersing or applying a treatment liquid in a treatment liquid containing a polyhydric phenol carboxylic acid such as tannic acid and a silane coupling agent (for example, Patent Document 1, Patent Document 2, etc.)
(2) A method of forming a film using a treatment liquid in which a polyhydric phenol carboxylic acid such as tannic acid or a phosphoric acid compound is blended with an organic resin (for example, Patent Document 3 to Patent Document 6)
(3) A method of applying a film containing an organic resin and a silane coupling agent (for example, Patent Document 7 to Patent Document 13)
(4) A method of applying a film in which an organic titanate compound is mixed with an aqueous dispersion resin or a water-soluble resin (for example, Patent Document 14 and Patent Document 15)

JP 7-216268 A Japanese Patent No. 2968959 JP-A-8-325760 JP 2000-34578 A JP 2000-199076 A JP 2000-248380 A JP-A-11-106945 JP 2000-319787 A JP 2000-248384 A Japanese Patent Laid-Open No. 2000-177871 JP 2000-199076 A JP 2000-281946 A Japanese Patent Laid-Open No. 2000-14443 JP 2003-155451 A JP 2003-253464 A

As the method of (1), there is a method of treating with an aqueous solution in which a polyhydric phenol carboxylic acid and a silane coupling agent, and further metal ions are blended. . However, this treatment method has a drawback that satisfactory adhesion cannot be obtained although good adhesion can be obtained.
As the above method (2), for example, Patent Document 3 discloses a method in which treatment is performed with a treatment liquid in which polyhydric phenolcarboxylic acid, an organic resin, and metal ions are blended. Patent Document 4 discloses a method of immersing in a treatment liquid to which an organic resin and a phosphoric acid compound are added or applying a treatment liquid and then drying. However, although the protective film formed by these treatment liquids contributes to a certain degree to the improvement of the corrosion resistance, a high degree of corrosion resistance as in the case of the chromate treatment cannot be obtained.

  As the method (3), for example, Patent Document 8 and Patent Document 9 disclose a method having a film containing an organic resin and a silane coupling agent, and further a thiocarbonyl compound, a phosphate compound, and a vanadium compound. However, the corrosion resistance is not sufficient because the organic resin is polyurethane or acrylic olefin resin. Patent Document 11 has a film made of an acid-modified epoxy resin. Patent Document 10 discloses a resin containing a hydroxyl group / carboxyl group / glycidyl group / phosphate group-containing monomer as a copolymerization component, a silane coupling agent, Although the thing which has the membrane | film | coat which mix | blended the phosphoric acid compound is disclosed, respectively, also about these, corrosion resistance is not enough. Patent Document 7 discloses a film having a film in which an etching agent such as a polyvinylphenol derivative, a silane coupling agent, and phosphoric acid is blended. However, sufficient corrosion resistance cannot be obtained. Patent Document 12 discloses a film having an organic resin blended with an etching agent, and Patent Document 13 discloses a film having a film blended with an organic resin and a silane coupling agent. There is no description and the corrosion resistance is insufficient.

In addition, as a method of the above (4), Patent Document 14 discloses a technique for improving adhesion with a base steel sheet by adding an organic titanate compound to a water-dispersible resin. A technique for improving the adhesion to a base steel sheet by adding a titanium compound and a zirconium compound to a water-soluble resin is shown. However, a water-dispersible resin or a water-soluble resin has a weak barrier property against a corrosion factor and cannot provide sufficient corrosion resistance. Moreover, it does not have sufficient durability against alkaline degreasing. Further, a combination of these with an organic titanate compound, a titanium compound, or a zirconium compound only improves the adhesion, and hardly contributes to the improvement of the barrier property against the corrosion factor.
Accordingly, an object of the present invention is to provide a surface-treated steel sheet that solves such problems of the prior art and does not contain chromium in the film and that provides excellent corrosion resistance.

In order to solve the above-mentioned problems, the present inventors have conducted the following investigation on the principle of corrosion inhibition for inhibiting corrosion of the plated steel sheet.
The corrosion of the zinc-based plated steel sheet on which the surface treatment film is formed proceeds in the following process.
(1) Corrosion factors (oxygen, water, chlorine ions, etc.) infiltrate into the surface treatment film and diffuse to the plating film / surface treatment film interface.
(2) At the plating film / surface treatment film interface, zinc is dissolved by the following oxidation-reduction reaction.
Cathode reaction: 2H ₂ O + O ₂ + 4e ⁻
→ 4OH ⁻
Anode reaction: 2Zn → 2Zn ²⁺ + 4e ⁻

Therefore, to improve the corrosion resistance of the galvanized steel sheet, it is essential to suppress the progress of both reactions (1) and (2).
(A) Advanced barrier layer that acts as a diffusion barrier for corrosion factors (mainly suppresses the cathode reaction)
(B) Reaction layer with plating metal that inactivates the plating film surface layer (mainly acts to suppress the anode reaction)
It is most effective to have a film configuration that has a self-repairing action when a defect occurs in the reaction layer.

  As a result of the study, such a film configuration is not a two-layer film formed by separately coating a barrier layer forming component and a reaction layer forming component as in the prior art, but a single layer formed by a single coating. Realizing in the film, specifically, forming the barrier layer (a) above the film and the reaction layer (b) above the film, more preferably self-repairing action in the film. It has been found that the effect of improving the corrosion resistance can be obtained by synergistic effects by precipitating the substance to be generated. When such a single-layer coating is defined as a pseudo-two-layer coating, the barrier layer and the reaction layer constituting the pseudo-two-layer coating are between the two-layer coating formed by the conventional double coating. There is no clear interface. On the contrary, it is considered that a high degree of corrosion resistance improvement effect that cannot be obtained by the conventional single layer coating can be exhibited by making the both compositions in a gradient composition.

The pseudo two-layer film as described above is prepared by reacting a water-dispersible liquid of a resin obtained by reacting a specific modified epoxy resin with a hydrazine derivative having active hydrogen, and a silane coupling agent and a specific acid component (phosphoric acid). , Hexafluorometal acid, etc.) is applied to the surface of a zinc-based plated steel sheet or an aluminum-based plated steel sheet and dried.
A silane coupling agent is known to have an effect of improving the adhesion between an inorganic compound and an organic compound so far, and can improve the adhesion between a plating metal and a water-dispersible resin. When the above-mentioned specific surface treatment composition is used for the known effects of such a silane coupling agent, the acid component contained in the surface treatment composition activates the plating film surface by etching, It is considered that extremely excellent adhesion between the plating metal and the film-forming resin can be obtained by chemically bonding the silane coupling agent with both the activated plating metal and the film-forming resin. That is, by adding a silane coupling agent and a specific acid component to the surface treatment composition, the adhesion between the plating metal and the film-forming resin is markedly greater than when the silane coupling agent is added alone. As a result, it is considered that the progress of corrosion of the plated metal is effectively suppressed and particularly excellent corrosion resistance can be obtained.

  Although the mechanism by which the pseudo two-layer film having the above-described film structure is formed is not necessarily clear, the reaction between the acid component in the surface treatment composition and the surface of the plating film may be involved in the film formation. On the other hand, the following actions involving a silane coupling agent are also conceivable. That is, since the silane coupling agent hydrolyzed in an aqueous solution has a silanol group (Si—OH), the hydrogen bonding adsorption action of the silane coupling agent on the surface of the plating metal activated by the acid component is promoted. When the silane coupling agent is concentrated on the metal surface and then dried, a dehydration condensation reaction takes place to form a strong chemical bond, thereby inactivating the reaction layer (b) above the coating layer (ie, the plating coating surface layer). (Reaction layer with plating metal) is formed, and the barrier layer of (a) above (that is, a high barrier layer serving as a diffusion barrier for corrosion factors) is formed by the water-dispersible resin concentrated on the upper part of the film. There is also a possibility by the mechanism. In addition, there is a possibility that the above-described action occurs in a composite manner. In addition, in the film formation process as described above, it is considered that a reaction product (compound) between a dissolved plating metal such as zinc and an acid component is deposited in the film.

  Although the anticorrosion mechanism of such a pseudo-bilayer coating is not necessarily clear, the individual anticorrosion mechanism includes a dense organic polymer by adding a hydrazine derivative to a specific modified epoxy resin as the barrier layer of (a) above. A molecular film is formed, which suppresses the permeation of corrosion factors (oxygen, water, chlorine ions, etc.) and effectively suppresses the cathodic reaction that causes corrosion, and also prevents the plating metal ions eluted by the corrosion reaction. The free hydrazine derivative in the film traps to form a stable insoluble chelate compound layer, and the reaction layer in (b) above effectively inactivates the surface layer of the plating film to effectively cause an anodic reaction that causes corrosion. In addition, the precipitated compounds deposited in the film dissolve in a corrosive environment and acid components (phosphate ions, etc.) are generated. A self-repairing action that captures metal ions such as zinc ions eluted from the film (bonds with metal ions to form an insoluble compound), and is a plated metal in which a silane coupling agent is activated by an acid component. It is possible to form a dense film with high adhesion by binding to the surface firmly, suppressing dissolution of the plating metal, and also bonding with the film-forming resin. It is considered that extremely excellent corrosion resistance (white rust resistance) can be obtained.

  Further, by adding a water-soluble phosphate or a non-chromium rust preventive additive to the surface treatment composition, further excellent corrosion resistance can be obtained. In the same way as above, the poorly soluble film exhibits a barrier against corrosion factors, and the phosphate component captures the eluted plating metal ions, forming an insoluble compound with the plating metal ions. It is possible to do. Further, since the non-chromium rust preventive additive forms a protective film at the starting point of corrosion, further excellent anticorrosive performance can be obtained. In practice, these combined effects provide very good anticorrosion performance.

  The above is the anticorrosion mechanism of the surface treatment film obtained by the specific treatment composition, but according to the results of the study by the present inventors, an organic film was simply formed on such a surface treatment film or an upper layer thereof. In the two-layer coating structure, it was found that, particularly when subjected to severe processing such as a wrinkle presser bead in an automobile press die, the processed portion was greatly damaged and its corrosion resistance was considerably inferior. Furthermore, it has been found that the damaged part of the film is damaged by the alkaline degreasing performed to remove the oil after the processing, and the corrosion resistance is further deteriorated. Therefore, as a result of studying the coating composition that is highly satisfactory for the corrosion resistance of the processed part when subjected to such severe processing and further subjected to alkaline degreasing, the second layer film is formed on the surface treatment film as described above, and contains an epoxy group. By forming a film containing a resin (preferably a high molecular weight epoxy group-containing resin having a number average molecular weight of 6000 to 20000), a urethane resin, and an organometallic compound in which a specific metal atom and an organic group are bonded. It has been found that a high degree of anticorrosion effect can be obtained even in the portion subjected to the above severe processing and alkali degreasing. That is, the present invention has been found that by combining the specific surface treatment film (lower film) and the specific upper film, particularly high corrosion resistance of the processed part can be obtained by their combined action.

The present invention has been made on the basis of such findings, and the features thereof are as follows.
[1] The coating thickness formed by applying a surface treatment composition containing the following components (a) to (c) to the surface of a zinc-based plated steel sheet or an aluminum-based plated steel sheet and drying is 0.01 to Having a surface treatment film of 1.0 μm,
(A) a polyalkylene glycol-modified epoxy resin (A) obtained by reacting a polyalkylene glycol having a number average molecular weight of 400 to 20,000, a bisphenol type epoxy resin, an active hydrogen-containing compound and a polyisocyanate compound, and the polyalkylene glycol-modified A resin obtained by reacting an epoxy group-containing resin (B) other than the epoxy resin (A) with an active hydrogen-containing compound comprising a hydrazine derivative (C) in which some or all of the compounds have active hydrogen is used in water. Dispersed aqueous epoxy resin dispersion (b) Silane coupling agent: 1 to 300 parts by mass with respect to 100 parts by mass of the solid content of the aqueous epoxy resin dispersion (c) Phosphoric acid and / or hexafluorometal acid: 0.1 to 80 quality with respect to 100 parts by mass of the solid content of the aqueous epoxy resin dispersion Part The upper layer contains an epoxy group-containing resin (E), a urethane resin (F), and one or more organic metal compounds (G) selected from organic titanium compounds, organic zirconium compounds, and organic aluminum compounds. A highly corrosion-resistant surface-treated steel sheet, characterized by having an upper film having a film thickness of 0.3 to 2.0 μm formed by applying and drying a coating composition for an upper film.

[2] The surface-treated steel sheet according to [1] above, wherein the epoxy group-containing resin (E) contained in the upper layer coating composition is a high molecular weight epoxy group-containing resin having a number average molecular weight of 6000 to 20000. High corrosion resistance surface treated steel sheet.
[3] The surface-treated steel sheet according to [1] or [2], wherein the organometallic compound (G) contained in the upper layer coating composition has an ester bond in its molecular structure. Surface treated steel sheet.
[4] In the surface-treated steel sheet according to any one of the above [1] to [3], the coating composition for the upper layer coating is 100 parts by mass of the total solid content of the epoxy group-containing resin (E) and the urethane resin (F). In contrast, a highly corrosion-resistant surface-treated steel sheet containing 0.1 to 10 parts by mass of the organometallic compound (G).

[5] In the surface-treated steel sheet according to any one of the above [1] to [4], the surface treatment composition for forming a surface treatment film further comprises a water-soluble phosphate, and an aqueous epoxy resin dispersion of component (a) A highly corrosion-resistant surface-treated steel sheet, containing 0.1 to 60 parts by mass of solids with respect to 100 parts by mass of solids.
[6] In the surface-treated steel sheet according to any one of the above [1] to [5], the surface treatment composition for forming the surface treatment film further comprises a non-chromium rust preventive additive and an aqueous epoxy resin as component (a) A highly corrosion-resistant surface-treated steel sheet comprising 0.1 to 50 parts by mass of solids with respect to 100 parts by mass of solids in the dispersion.
[7] In the surface-treated steel sheet according to any one of the above [1] to [6], the coating composition for the upper film further includes a non-chromium rust preventive additive with respect to 100 parts by mass of the resin solid content of the coating composition. A high corrosion resistance surface-treated steel sheet, characterized by containing 0.1 to 50 parts by mass in a solid content ratio.

[8] In the surface-treated steel sheet according to any one of the above [1] to [7], the surface treatment composition for forming the surface treatment film and / or the coating composition for the upper film is used as the non-chromium rust preventive additive, A highly corrosion-resistant surface-treated steel sheet comprising one or more selected from (e1) to (e7).
(E1) Silicon oxide (e2) Calcium compound (e3) Slightly soluble phosphate compound (e4) Molybdate compound (e5) Vanadium compound (e6) Triazoles, thiols, thiadiazoles, thiazoles, thiurams One or more organic compounds containing S atoms (e7) One or more organic compounds containing N atoms selected from hydrazide compounds, pyrazole compounds, triazole compounds, tetrazole compounds, thiadiazole compounds, and pyridazine compounds

[9] In the surface-treated steel sheet according to any one of [1] to [8] above, the coating composition for the upper layer film further comprises a curing agent having a group that crosslinks with a hydroxyl group, an epoxy group-containing resin (E) and a urethane resin. A highly corrosion-resistant surface-treated steel sheet, containing 1 to 50 parts by mass of solid content with respect to 100 parts by mass of the total solid content of (F).
[10] In the surface-treated steel sheet according to [9], the curing agent having a group capable of crosslinking with a hydroxyl group is an amino resin (H) having an average of one or more imino groups in one molecule. Surface treated steel sheet.
[11] The surface-treated steel sheet according to [9], wherein the curing agent having a group that crosslinks with a hydroxyl group is a polyisocyanate compound (I) having an average of 4 or more isocyanate groups in one molecule. Corrosion-resistant surface-treated steel sheet.

[12] The surface-treated steel sheet according to [11], wherein the polyisocyanate compound (I) is obtained by blocking at least a part of isocyanate groups of the polyisocyanate compound with a blocking agent. steel sheet.
[13] The surface-treated steel sheet according to any one of [1] to [12] above, wherein the epoxy group-containing resin (E) contained in the upper layer coating composition is a hydrazine in which some or all of the compounds have active hydrogen. A highly corrosion-resistant surface-treated steel sheet, which is a modified epoxy group-containing resin modified with an active hydrogen-containing compound (J) comprising a derivative (K).
[14] In the surface-treated steel sheet according to any one of [1] to [13], the upper layer coating composition further includes a solid lubricant with a solid content of 100 parts by mass of the resin solid content of the coating composition. A highly corrosion-resistant surface-treated steel sheet containing 1 to 30 parts by mass in a proportion.

[15] A surface treatment composition containing the following components (a) to (c) is applied to the surface of a zinc-based plated steel sheet or an aluminum-based plated steel sheet, and dried at a temperature of 30 to 150 ° C. To form a surface treatment film having a film thickness of 0.01 to 1.0 μm,
(A) a polyalkylene glycol-modified epoxy resin (A) obtained by reacting a polyalkylene glycol having a number average molecular weight of 400 to 20,000, a bisphenol type epoxy resin, an active hydrogen-containing compound and a polyisocyanate compound, and the polyalkylene glycol-modified A resin obtained by reacting an epoxy group-containing resin (B) other than the epoxy resin (A) with an active hydrogen-containing compound comprising a hydrazine derivative (C) in which some or all of the compounds have active hydrogen is used in water. Dispersed aqueous epoxy resin dispersion (b) Silane coupling agent: 1 to 300 parts by mass with respect to 100 parts by mass of the solid content of the aqueous epoxy resin dispersion (c) Phosphoric acid and / or hexafluorometal acid: 0.1 to 80 quality with respect to 100 parts by mass of the solid content of the aqueous epoxy resin dispersion Part The upper layer contains an epoxy group-containing resin (E), a urethane resin (F), and one or more organic metal compounds (G) selected from organic titanium compounds, organic zirconium compounds, and organic aluminum compounds. A high corrosion-resistant surface characterized in that an upper layer film is formed by applying a coating composition for an upper layer film and drying at a temperature of the ultimate plate temperature of 30 to 150 ° C. A method for producing a treated steel sheet.
[16] In the production method of [15] above, the epoxy group-containing resin (E) contained in the upper layer coating composition is a high molecular weight epoxy group-containing resin having a number average molecular weight of 6000 to 20000. A method for producing a highly corrosion-resistant surface-treated steel sheet.

  The surface-treated steel sheet of the present invention has a very excellent flat plate and post-processing corrosion resistance despite the fact that it does not contain chromium in the film, and also has excellent weldability and paintability. For this reason, the surface-treated steel sheet of the present invention is particularly useful for automobile applications.

The details of the present invention and the reasons for limitation will be described below.
Examples of the zinc-based plated steel sheet used as the base of the surface-treated steel sheet of the present invention include galvanized steel sheet, Zn-Ni alloy-plated steel sheet, 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 plating Steel plate (for example, Zn-5% Al alloy-plated steel plate, Zn-55% Al alloy-plated steel plate), Zn-Mg alloy-plated steel plate, Zn-Al-Mg alloy-plated steel plate (for example, Zn-6% Al-3% Mg) Alloy-plated steel sheets, Zn-11% Al-3% Mg alloy-plated steel sheets), and metal oxides, polymers, etc. are dispersed in the plating film of these plated steel sheets Zinc-based composite-plated steel sheet (for example, Zn-SiO ₂ dispersion plating steel plate) was the like 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 non-aqueous 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, Fe are deposited in the plating film, or one of Ni, Co, Fe is deposited on the surface of the plating film. These elements may be deposited by performing a surface conditioning treatment with an alkaline aqueous solution or an 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 applied with a surface treatment composition containing the following components (a) to (c) and dried. It is the surface treatment film | membrane formed by this. This surface treatment film does not contain any chromium.
(A) a polyalkylene glycol-modified epoxy resin (A) obtained by reacting a polyalkylene glycol having a number average molecular weight of 400 to 20,000, a bisphenol type epoxy resin, an active hydrogen-containing compound and a polyisocyanate compound, and the polyalkylene glycol-modified An epoxy group-containing resin (B) other than the epoxy resin (A), a hydrazine derivative (C) having active hydrogen, and an active hydrogen-containing compound (D) other than the hydrazine derivative (C) as necessary. An aqueous epoxy resin dispersion obtained by dispersing the resin obtained by the reaction in water (b) Silane coupling agent: 1 to 300 parts by mass with respect to 100 parts by mass of the solid content of the aqueous epoxy resin dispersion (c) Phosphoric acid and / or hexafluorometal acid: solid content of the aqueous epoxy resin dispersion 10 0.1 to 80 parts by mass per part by mass

The surface treatment composition for forming the surface treatment film needs to be a water-solvent type in order to generate a compound layer (amorphous compound layer) or a precipitated compound as described above, and therefore, as an organic resin A water dispersible resin is used.
First, the aqueous epoxy resin dispersion that is the component (a) will be described.
This aqueous epoxy resin dispersion includes a specific polyalkylene glycol-modified epoxy resin (A), an epoxy group-containing resin (B) other than the polyalkylene glycol-modified epoxy resin (A), and a hydrazine derivative (C ) And, if necessary, a resin obtained by reacting an active hydrogen-containing compound (D) other than the hydrazine derivative (C), is dispersed in water.

The polyalkylene glycol-modified epoxy resin (A) is obtained by reacting a polyalkylene glycol having a number average molecular weight of 400 to 20000, a bisphenol type epoxy resin, an active hydrogen-containing compound, and a polyisocyanate compound. .
As the polyalkylene glycol, for example, polyethylene glycol, polypropylene glycol, polybutylene glycol and the like can be used, and among them, polyethylene glycol is particularly preferable. The number average molecular weight of the polyalkylene glycol is suitably in the range of 400 to 20000, preferably 500 to 10,000, from the viewpoint of water dispersibility and storage properties of the resulting resin.
The bisphenol-type epoxy resin is a bisphenol compound having at least one epoxy group in one molecule, and in particular, a bisphenol diester obtained by a condensation reaction between a bisphenol compound and an epihalohydrin (for example, epichlorohydrin). Glycidyl ether is preferable because a film excellent in flexibility and corrosion resistance can be easily obtained.

Representative examples of bisphenol compounds that can be used for the preparation of bisphenol type epoxy resins include bis (4-hydroxyphenyl) -2,2-propane, bis (4-hydroxyphenyl) -1,1-ethane, and bis. (4-hydroxyphenyl) -methane, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenylsulfone, bis (4-hydroxyphenyl) -1,1-isobutane, bis (4-hydroxy-3-t- Butylphenyl) -2,2-propane and the like. Of the epoxy resins prepared using such bisphenol compounds, bisphenol A type epoxy resins are particularly suitable in that a film excellent in flexibility and anticorrosion properties can be obtained.
The bisphenol-type epoxy resin generally has a number average molecular weight of about 310 to 10,000, particularly preferably about 320 to 2,000, from the viewpoint of production stability at the time of production of the polyalkylene glycol-modified epoxy resin. The epoxy equivalent is preferably in the range of about 155 to 5000, particularly desirably about 160 to 1000.

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

  The polyisocyanate compound is a compound having 2 or more, preferably 2 or 3 isocyanate groups in one molecule, and those generally used for the production of polyurethane resins can be used in the same manner. Such polyisocyanate compounds include aliphatic, alicyclic and aromatic polyisocyanate compounds. Representative examples include aliphatic polyisocyanate compounds such as hexamethylene diisocyanate (HMDI), HMDI biuret compound, HMDI isocyanurate compound; isophorone diisocyanate (IPDI), IPDI biuret compound, IPDI isocyanurate compound, Examples thereof include alicyclic polyisocyanate compounds such as hydrogenated xylylene diisocyanate and hydrogenated 4,4′-diphenylmethane diisocyanate; aromatic polyisocyanate compounds such as tolylene diisocyanate and xylylene diisocyanate.

In general, the blending ratio of each component during the production of the polyalkylene glycol-modified epoxy resin (A) is suitably in the following range.
That is, the equivalent ratio of the hydroxyl group of the polyalkylene glycol to the isocyanate group of the polyisocyanate compound is 1 / 1.2 to 1/10, preferably 1 / 1.5 to 1/5, particularly preferably 1 / 1.5 to A value of 1/3 is appropriate. The equivalent ratio of the hydroxyl group of the active hydrogen-containing compound to the isocyanate group of the polyisocyanate compound is 1/2 to 1/100, preferably 1/3 to 1/50, particularly preferably 1/3 to 1/20. Is appropriate. The equivalent ratio of the total amount of hydroxyl groups of the polyalkylene glycol, the bisphenol type epoxy resin and the active hydrogen-containing compound to the isocyanate group of the polyisocyanate compound is 1 / 1.5 or less, preferably 1 / 0.1 to 1/1. .5, particularly preferably 1 / 0.1 to 1 / 1.1.

The reaction of the polyalkylene glycol, the bisphenol type epoxy resin, the active hydrogen-containing compound and the polyisocyanate compound can be performed by a known method.
The polyalkylene glycol-modified epoxy resin (A) obtained above, an epoxy group-containing resin (B) other than the polyalkylene glycol-modified epoxy resin (A), a hydrazine derivative (C) having active hydrogen, and further necessary Accordingly, by reacting with the active hydrogen-containing compound (D) other than the hydrazine derivative (C), an epoxy resin that can be easily dispersed in water and has good adhesion to the material can be obtained. .

As the epoxy group-containing resin (B) other than the polyalkylene glycol-modified epoxy resin (A), a glycidyl group is introduced by reacting polyphenols such as bisphenol A, bisphenol F, and novolac type phenol with an epihalohydrin such as epichlorohydrin. Or an aromatic epoxy resin obtained by further reacting this glycidyl group-introduced reaction product with a polyphenol to increase the molecular weight; and further, an aliphatic epoxy resin, an alicyclic epoxy resin, etc. One kind can be used alone, or two or more kinds can be mixed and used. 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 epoxy group-containing resin (B) include resins obtained by reacting various modifiers with epoxy groups or hydroxyl groups in the epoxy group-containing resin. For example, epoxy ester resins obtained by reacting a dry oil fatty acid. An epoxy acrylate resin modified with a polymerizable unsaturated monomer component containing acrylic acid or methacrylic acid; a urethane-modified epoxy resin reacted with an isocyanate compound;

Further, as the epoxy group-containing resin (B), an unsaturated monomer having an epoxy group and a polymerizable unsaturated monomer component essentially comprising an acrylic ester or a methacrylic ester are used as a solution polymerization method, emulsion polymerization method or suspension polymerization method. An acrylic copolymer resin copolymerized with an epoxy group-containing monomer synthesized by a method such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl ( Acrylic acid or methacrylic acid such as (meth) acrylate, n-, iso- or tert-butyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, decyl (meth) acrylate, lauryl (meth) acrylate C1-C24 Alkyl ester; acrylic acid, methacrylic acid, styrene, vinyl toluene, acrylamide, acrylonitrile, N-methylol (meth) acrylamide, C1-4 alkyl etherified product of N-methylol (meth) acrylamide; N, N-diethylaminoethyl methacrylate, etc. Can be mentioned. Moreover, as an unsaturated monomer which has an epoxy group, as long as it has an epoxy group and a polymerizable unsaturated group, such as glycidyl methacrylate, glycidyl acrylate, 3,4 epoxycyclohexyl-1-methyl (meth) acrylate, It is not limited.
The acrylic copolymer resin may be a resin modified with a polyester resin, an epoxy resin, a phenol resin, or the like.

上記化学構造式中、ｑは０〜５０の整数、好ましくは１〜４０の整数、特に好ましくは２〜２０の整数である。
このようなビスフェノールＡ型エポキシ樹脂は、当業界において広く知られた製造法により得ることができる。 Particularly preferable as the epoxy group-containing resin (B) is a resin represented by the following chemical structural formula, which is a reaction product of bisphenol A and epiparohydrin, and is particularly preferable because of its excellent corrosion resistance.

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

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

The following can be mentioned as a typical example of the amine compound which has the said activated hydrogen.
(1) a primary amino group of an amine compound containing one secondary amino group and one or more primary amino groups, such as diethylenetriamine, hydroxyethylaminoethylamine, ethylaminoethylamine, methylaminopropylamine, etc .; A compound modified with aldimine, ketimine, oxazoline or imidazoline by heating reaction with aldehyde or carboxylic acid at a temperature of about 100 to 230 ° C., for example;
(2) Secondary monoamines such as diethylamine, diethanolamine, di-n- or -ios-propanolamine, N-methylethanolamine, N-ethylethanolamine;
(3) a secondary amine-containing compound obtained by adding a monoalkanolamine such as monoethanolamine and a dialkyl (meth) acrylamide by a Michael addition reaction;
(4) A compound obtained by modifying a primary amine group of 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 can react with an epoxy group because a hydrazine derivative or a tertiary amine that does not have an active hydrogen is not reactive with an epoxy group by itself. Therefore, it is a mixture with an 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.

It is a hydrazine derivative having active hydrogen that exhibits the most useful and excellent corrosion resistance performance among the active hydrogen-containing compounds.
Specific examples of the hydrazine derivative having active hydrogen include the following.
(A) 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;

(B) pyrazole compounds such as pyrazole, 3,5-dimethylpyrazole, 3-methyl-5-pyrazolone, 3-amino-5-methylpyrazole;
(C) 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;

(D) tetrazole compounds such as 5-phenyl-1,2,3,4-tetrazole and 5-mercapto-1-phenyl-1,2,3,4-tetrazole;
(E) thiadiazole compounds such as 5-amino-2-mercapto-1,3,4-thiadiazole, 2,5-dimercapto-1,3,4-thiadiazole;
(F) 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;
Of 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.

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

  The above 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. Indicates possible, it is possible to use one or more of these. Of these, ketone-based or ether-based solvents are particularly preferable from the viewpoints of solubility with an epoxy resin, film formation, and the like.

The blending ratio of the polyalkylene glycol-modified epoxy resin (A), the epoxy group-containing resin (B) other than the polyalkylene glycol-modified epoxy resin (A), and the hydrazine derivative (C) having active hydrogen is polyalkylene glycol-modified. The equivalent ratio of active hydrogen groups in the hydrazine derivative (C) to the epoxy groups in the epoxy resin (A) and the epoxy group-containing resin (B) is 0.01 to 10, preferably 0.1 to 8, and more preferably 0. 2 to 4 is appropriate from the viewpoints of corrosion resistance and water dispersibility of the resin.
Further, as described above, a part of the hydrazine derivative (C) having active hydrogen can be replaced with the active hydrogen-containing compound (D), but the amount to be replaced (that is, the active hydrogen-containing compound including the hydrazine derivative (C)) The proportion of the active hydrogen-containing compound (D) in the composition is 90 mol% or less, preferably 70 mol% or less, more preferably 10 to 60 mol%, from the viewpoint of corrosion resistance and adhesion. It is.

  Moreover, in order to form a dense barrier film, it is desirable to mix a curing agent in the resin composition and heat cure the film. The curing method for forming a film with the resin composition was selected from (1) a curing method using a urethanization reaction between an isocyanate and a hydroxyl group in a base resin, and (2) melamine, urea, and benzoguanamine. Etherification reaction between an alkyl etherified amino resin obtained by reacting one or more methylol compounds obtained by reacting formaldehyde with one or more monovalent alcohols having 1 to 5 carbon atoms and a hydroxyl group in the base resin. However, it is particularly preferable to use a urethanization reaction between an isocyanate and a hydroxyl group in the base resin as a main reaction.

The polyisocyanate compound as a curing agent that can be used in the curing method (1) is an aliphatic, alicyclic (including heterocyclic) or aromatic isocyanate compound having at least two isocyanate groups in one molecule. Or a compound obtained by partially reacting these compounds with a polyhydric alcohol. Examples of such polyisocyanate compounds include the following.
(A) m- or p-phenylene diisocyanate, 2,4- or 2,6-tolylene diisocyanate, o- or p-xylylene diisocyanate, hexamethylene diisocyanate, dimer acid diisocyanate, isophorone diisocyanate (B) above (A) Or a mixture thereof and polyhydric alcohols (dihydric alcohols such as ethylene glycol and propylene glycol; trihydric alcohols such as glycerin and trimethylolpropane; tetrahydric alcohols such as pentaerythritol; sorbitol, dipentaerythritol, etc. These compounds are reaction products with 6-valent alcohol, etc., and at least two isocyanates remain in one molecule. These polyisocyanate compounds are used alone or in combination of two or more. it can.

Moreover, as a protective agent (blocking agent) of a polyisocyanate compound, for example,
(I) aliphatic monoalcohols such as methanol, ethanol, propanol, butanol, octyl alcohol;
(Ii) ethylene glycol and / or diethylene glycol monoethers, for example, monoethers such as methyl, ethyl, propyl (n-, iso), butyl (n-, iso, sec);
(Iii) aromatic alcohols such as phenol and cresol;
(Iv) oximes such as acetooxime and methyl ethyl ketone oxime;
A polyisocyanate compound that is stably protected at least at room temperature can be obtained by reacting one or more of these with the polyisocyanate compound.

  Such a polyisocyanate compound (a2) has a curing agent of (a) / (a2) = 95/5 to 55/45 (nonvolatile) with respect to the aqueous epoxy resin dispersion (a) (the component (a)). (Mass ratio of minute), preferably (a) / (a2) = 90/10 to 65/35. The polyisocyanate compound has water absorption, and if it is blended in excess of (a) / (a2) = 55/45, the adhesion of the surface treatment film is deteriorated. Furthermore, the unreacted polyisocyanate compound moves into the upper layer film, which causes inhibition of curing of the upper layer film and poor adhesion. From such a viewpoint, the blending amount of the polyisocyanate compound (a2) is preferably (a) / (a2) = 55/45 or less.

The water-dispersible resin 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 the purpose of slightly improving physical properties such as adhesion, a known resin such as acrylic, alkyd, or polyester can be mixed with the epoxy group-containing resin (B).

The reaction product of polyalkylene glycol-modified epoxy resin (A), epoxy group-containing resin (B), and hydrazine derivative (C) having active hydrogen (and active hydrogen-containing compound (D) if necessary) is dispersed in water. For example, the following method can be employed.
(1) A tertiary amine which is a neutralizing agent by reacting an epoxy group of an epoxy group-containing resin (ie, resin (A) or (B)) with a dibasic acid or secondary amine which is an active hydrogen-containing compound. , Neutralization with acetic acid or phosphoric acid, water dispersion (2) Using a modified epoxy resin obtained by reacting an epoxy resin with a terminal hydroxyl group-containing polyalkylene oxide such as polyethylene glycol or polypropylene glycol with an isocyanate, Method of water dispersion (3) Method of using both (1) and (2) above In addition to the specific water-dispersible resin described above, other water-dispersible resins and / or water-soluble resins are included in the surface treatment composition. For example, acrylic resin, urethane resin, polyester resin, epoxy resin, ethylene resin, alkyd resin, phenol resin, One or more fins or the like resin, may be blended as an upper limit of about 15 mass% in a ratio of the total resin solids in the.

Next, the silane coupling agent which is the said component (b) is demonstrated.
Examples of the silane coupling agent include vinyl methoxy silane, vinyl ethoxy silane, vinyl trichloro silane, vinyl trimethoxy silane, vinyl triethoxy silane, β- (3,4 epoxy cyclohexyl) ethyl trimethoxy silane, and γ-glycid. Xylpropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltriethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, N-β (aminoethyl) γ -Aminopropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-me Tacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-mercaptopropylmethyldimethoxysilane, γ-mercaptopropyltrimethoxysilane, p-styryltrimethoxysilane, γ -Acryloxypropyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, γ-chloropropyltrimethoxysilane, bis (triethoxysilylpropyl) tetrasulfide, γ-isocyanatopropyl Triethoxysilane, γ-triethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine, N- (vinylbenzylamine) -β-aminoethyl-γ-aminopropyltri Etc. can be mentioned Tokishishiran, these one may be used alone or in combination of two or more.

In the present invention, the reason described above can be considered to improve the white rust resistance by including the silane coupling agent together with the specific acid component in the surface treatment composition.
Among the silane coupling agents, a silane coupling agent having an amino group as a reactive functional group is particularly preferable from the viewpoint of having a functional group highly reactive with the water-dispersible resin of the component (a). preferable. Examples of such silane coupling agents include N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, and N-β (aminoethyl) γ. -Aminopropyltrimexysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and the like. Specifically, KBM-903, KBE-903, and KBM-603 manufactured by Shin-Etsu Chemical Co., Ltd. , KBE-602, KBE-603 (both are trade names) and the like can be used.

  The compounding quantity of a silane coupling agent is 1-300 mass parts with respect to 100 mass parts of solid content of the aqueous | water-based epoxy resin dispersion which is the said component (a), Preferably it is 5-100 mass parts, More preferably, it is 15-50. The mass part is appropriate. If the amount of the silane coupling agent is less than 1 part by mass, the corrosion resistance is inferior. On the other hand, if it exceeds 300 parts by mass, a sufficient film cannot be formed, so that the effect of improving the adhesion and barrier properties with the water-dispersible resin can be exhibited. Therefore, the corrosion resistance is reduced.

Next, phosphoric acid and / or hexafluorometal acid, which is the component (c), acts on an inactive plating metal surface to activate the plating metal surface. The phosphoric acid and hexafluorometal acid may be used alone or in combination.
The kind of hexafluorometal acid is not particularly limited, but in particular hexafluorometal containing one or more elements selected from Ti, Si, Zr such as fluorinated titanic acid, fluorinated zirconic acid, and fluoric acid. Acids are preferred, and one or more of these can be used.
The total amount of phosphoric acid and / or hexafluorometal acid is 0.1 to 80 parts by mass, preferably 1 to 100 parts by mass of the solid content of the aqueous epoxy resin dispersion as component (a). 60 mass parts, more preferably 5-50 mass parts is suitable. If the blending amount of phosphoric acid and / or hexafluorometal acid is less than 0.1 parts by mass, the corrosion resistance is inferior. On the other hand, if it exceeds 80 parts by mass, the soluble component of the film increases, so that the corrosion resistance decreases.

A water-soluble phosphate can be blended with the surface treatment composition as necessary for the purpose of improving the corrosion resistance. As the water-soluble phosphate, for example, one or more metal salts such as orthophosphoric acid, pyrophosphoric acid, polyphosphoric acid, and metaphosphoric acid can be used. Moreover, you may add 1 or more types of the salt (for example, phytic acid, phytate, phosphonic acid, phosphonate, and these metal salts) of organic phosphoric acid. Of these, the primary phosphate is preferable from the viewpoint of the stability of the surface treatment composition.
There is no particular limitation on the form of phosphate present in the film, and it may be crystal or non-crystalline. There are no particular restrictions on the ionicity and solubility of the phosphate in the film. The reason why the corrosion resistance is improved by adding the water-soluble phosphate is considered that the water-soluble phosphate forms a dense hardly soluble compound at the time of film formation.

  As described above, the silane coupling agent chemically bonds with both the activated plating metal and the film-forming resin, thereby providing excellent adhesion and corrosion resistance between the plating metal and the film-forming resin. There are unavoidably inactive portions on the metal surface, and such an inactive site hardly causes the above-mentioned chemical bond and cannot sufficiently exhibit the rust prevention effect. The water-soluble phosphate forms a dense hardly soluble compound at the time of film formation on such a plated film portion. That is, as the plating film is dissolved by the phosphate ions of the water-soluble phosphate, the pH increases at the plating film / surface treatment composition interface, resulting in the formation of a precipitate film of the water-soluble phosphate, which is corrosion resistant. It contributes to the improvement.

From the viewpoint of obtaining particularly excellent corrosion resistance, Al, Mn, Ni, and Mg are particularly desirable as the cationic species of the water-soluble phosphate, and the water-soluble phosphorus containing one or more elements selected from these is preferred. It is preferable to use an acid salt. Examples of such water-soluble phosphates include primary aluminum phosphate, primary manganese phosphate, primary nickel phosphate, primary magnesium phosphate, and among these, primary aluminum phosphate is particularly preferable. Is most preferred. Moreover, it is preferable that the molar ratio [cation] / [P ₂ O ₅ ] of the cation component and the P ₂ O ₅ component is 0.4 to 1.0. If the molar ratio [cation] / [P ₂ O ₅ ] is less than 0.4, the solubility of the film is impaired by the soluble phosphoric acid, and the corrosion resistance is lowered. On the other hand, if it exceeds 1.0, the stability of the processing solution is remarkably lost, which is not preferable.

  The blending amount of the water-soluble phosphate is 0.1 to 60 parts by mass, preferably 0.00 with respect to 100 parts by mass of the solid content of the aqueous epoxy resin dispersion as the component (a). 5 to 40 parts by mass, more preferably 1 to 30 parts by mass is appropriate. If the blending amount of the water-soluble phosphate is less than 0.1 parts by mass, the effect of improving the corrosion resistance is not sufficient. On the other hand, if it exceeds 60 parts by mass, the soluble components of the film increase, so that the corrosion resistance tends to decrease. Therefore, it is not preferable.

A non-chromium rust preventive additive can be blended with the surface treatment composition as necessary for the purpose of improving the corrosion resistance. By blending such a non-chromium rust preventive additive into the surface treatment composition, particularly excellent anticorrosion performance (self-repairability) can be obtained.
As the non-chromium rust preventive additive, it is particularly preferable to use one or more selected from the following (e1) to (e7).
(E1) silicon oxide (e2) calcium compound (e3) sparingly soluble phosphate compound (e4) molybdate compound (e5) vanadium compound (e6) selected from triazoles, thiols, thiadiazoles, thiazoles, thiurams One or more organic compounds containing an S atom (e7) One or more organic compounds containing an N atom selected from hydrazide compounds, pyrazole compounds, triazole compounds, tetrazole compounds, thiadiazole compounds, and pyridazine compounds The details and anticorrosion mechanism of the non-chromium rust preventive additives (e1) to (e7) are as follows.

First, as the component (e1), colloidal silica or dry silica, which is fine particle silica, can be used. From the viewpoint of corrosion resistance, calcium ion-exchanged silica in which calcium is bound 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 AC3, SHIELDEX AC5 (all are trade names) manufactured by SHIELDEX, SHIELDEX manufactured by Fuji Silysia Chemical Co., Ltd.
SY710 (both are trade names) 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 (e2) and (e3) exhibit particularly excellent anticorrosion performance (self-repairing property) due to precipitation.
The calcium compound as the component (e2) may be any of calcium oxide, calcium hydroxide, and calcium salt, and one or more of these can be used. In addition, there are no particular restrictions on the type of calcium salt. In addition to simple salts containing only calcium as a cation such as calcium silicate, calcium carbonate, and calcium phosphate, calcium and calcium such as calcium phosphate / zinc, calcium phosphate / magnesium, etc. Double salts containing other cations may be used. The components (e2) is baser calcium than zinc and aluminum as the plating metal in a corrosive environment is preferentially dissolved, this OH produced by the cathode reaction ^- sequestering defective portion as a product of dense and poorly soluble 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 generated to block the corrosion and suppress the corrosion reaction.

  Further, as the hardly soluble phosphate compound (e3), 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.

As the molybdate compound (e4), 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 phosphoric acid molybdate 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.
As the vanadium compound (e5), for example, a pentavalent vanadium compound or a tetravalent vanadium compound can be applied. In particular, a tetravalent vanadium compound is preferable from the viewpoint of corrosion resistance.

  Examples of the organic compound (e6) include the following. 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.

  Examples of the organic compound (e7) include the following. That is, hydrazide compounds include carbohydrazide, propionic acid hydrazide, salicylic acid hydrazide, adipic acid dihydrazide, sebacic acid dihydrazide, dodecanoic acid dihydrazide, isophthalic acid dihydrazide, thiocarbohydrazide, 4,4'-oxybisbenzenesulfonylhydrazide, benzophenone. Aminopolyacrylamide and the like, and examples of the pyrazole compound include pyrazole, 3,5-dimethylpyrazole, 3-methyl-5-pyrazolone and 3-amino-5-methylpyrazole, and examples of the triazole compound include 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-mer Pto-1,2,4-triazole, 2,3-dihydro-3-oxo-1,2,4-triazole, 1H-benzotriazole, 1-hydroxybenzotriazole (monohydrate), 6-methyl-8 -Hydroxytriazolopyridazine, 6-phenyl-8-hydroxytriazolopyridazine, 5-hydroxy-7-methyl-1,3,8-triazaindolizine and the like, and tetrazole compounds include 5-phenyl-1 , 2,3,4-tetrazole, 5-mercapto-1-phenyl-1,2,3,4-tetrazole and the like, and as the thiadiazole compound, 5-amino-2-mercapto-1,3,4- Thiadiazole, 2,5-dimercapto-1,3,4-thiadiazole and the like, and pyridazine compounds include maleic acid hydride. Disilazide, 6-methyl-3-pyridazone, 4,5-dichloro-3-pyridazone, 4,5-dibromo-3-pyridazone, such as 6-methyl-4,5-dihydro-3-pyridazone may be mentioned, respectively. Of these, pyrazole compounds and triazole compounds having a 5- or 6-membered ring structure and having a nitrogen atom in the ring structure are particularly suitable.

  The compounding amount of the non-chromium rust preventive additive is 0.1 to 50 parts by mass, preferably 0 with respect to 100 parts by mass of the solid content of the aqueous epoxy resin dispersion as the component (a). It is appropriate that the content is 5 to 30 parts by mass. 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 alkali degreasing cannot be sufficiently obtained. On the other hand, if it exceeds 50 parts by mass, the corrosion resistance tends to decrease. It is not preferable.

Two or more rust preventive additives (e1) to (e7) may be added in combination, and 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 above component (e1), and one or more of the components (e3) to (e7), particularly preferably all of the components (e3) to (e7) are added to this. In particular, excellent corrosion resistance can be obtained.
In the surface treatment film (and surface treatment composition), other oxide fine particles (for example, aluminum oxide, zirconium oxide, titanium oxide, cerium oxide, antimony oxide, etc.), phosphomolybdate as corrosion inhibitors. One or two or more of organic inhibitors (for example, hydrazine and its derivatives, thiol compounds, thiocarbamates, etc.) can be added.

Further, if necessary, in the surface treatment film (and surface treatment composition), as an additive, an organic coloring pigment (for example, condensed polycyclic organic pigment, phthalocyanine organic pigment, etc.), a coloring dye (for example, water-soluble) Azo metal dyes), inorganic pigments (eg, titanium oxide), conductive pigments (eg, metal powders such as zinc, aluminum, nickel, iron phosphide, antimony-doped tin oxide, etc.), coupling agents (eg, 1 type, or 2 or more types, such as a titanium coupling agent) and a melamine cyanuric acid adduct.
The surface treatment film formed by the surface treatment composition containing the above components has a dry film thickness of 0.01 to 1.0 μm, preferably 0.1 to 0.8 μm. When the dry film thickness is less than 0.01 μm, the corrosion resistance is insufficient. On the other hand, when the dry film thickness exceeds 1.0 μm, the conductivity and workability are lowered.

Next, the upper layer film (organic film) formed as the second layer film on the surface treatment film will be described.
This upper layer film comprises an epoxy group-containing resin (E) (preferably a high molecular weight epoxy group-containing resin having a number average molecular weight of 6000 to 20000), a urethane resin (F), an organic titanium compound, an organic zirconium compound, and an organic aluminum. It is a film formed by applying and drying an upper layer coating composition containing at least one organometallic compound (G) selected from the compounds, preferably containing these as the main components. This upper layer film also contains no chromium. By forming the upper layer film containing such a specific component on the upper layer of the specific surface treatment film (lower layer film), particularly high corrosion resistance of the processed part can be obtained by the combined action of both films.

In the present invention, the reason why the epoxy group-containing resin (E) is used for the upper layer film is that the aspects such as reactivity, easiness of reaction, and anticorrosion are superior to those of other resins. Examples of the epoxy group-containing resin (E) include an epoxy resin, a modified epoxy resin, an acrylic copolymer resin copolymerized with an epoxy group-containing monomer, a polybutadiene resin having an epoxy group, a polyurethane resin having an epoxy group, and Examples include adducts or condensates of these resins, and one of these epoxy group-containing resins can be used alone or in admixture of two or more.
Of these epoxy group-containing resins (E), epoxy resins and modified epoxy resins are particularly preferred from the viewpoints of adhesion to the plating surface and corrosion resistance. Of these, thermosetting epoxy resins and modified epoxy resins with excellent barrier properties against corrosive factors such as oxygen are the most suitable, with a particularly low coating level for high spot weldability. This is particularly advantageous.

  As the epoxy group-containing resin (E), a high molecular weight epoxy group-containing resin having a number average molecular weight of 6000 to 20000, preferably 7000 to 12000 is particularly suitable. Of these, bisphenol-type epoxy resins are particularly preferred. Generally used bisphenol type epoxy resins have a number average molecular weight of 5500 or less, but if the number average molecular weight is less than 6000, the processability of the resulting film is not sufficient, especially for automotive press dies. The film damage when subjected to severe processing by a certain wrinkle presser bead is large, and the corrosion resistance of the processed part is inferior. On the other hand, when the number average molecular weight exceeds 20000, it is very difficult to produce an epoxy resin, and it becomes difficult to obtain a product having a stable quality due to gelation or the like.

  Examples of the bisphenol type epoxy resin include a resin obtained by condensing epichlorohydrin and bisphenol up to a high molecular weight in the presence of a catalyst such as an alkali catalyst, if necessary, and epichlorohydrin and bisphenol, if necessary, an alkali catalyst. Any of the resins obtained by condensation in the presence of a catalyst to form a low molecular weight epoxy resin and a polyaddition reaction of this low molecular weight epoxy resin and bisphenol may be used. The latter method is preferred for obtaining the above.

  Examples of the bisphenol include bis (4-hydroxyphenyl) methane [bisphenol F], 1,1-bis (4-hydroxyphenyl) ethane, 2,2-bis (4-hydroxyphenyl) propane [bisphenol A], 2,2-bis (4-hydroxyphenyl) butane [bisphenol B], bis (4-hydroxyphenyl) -1,1-isobutane, bis (4-hydroxy-tert-butyl-phenyl) -2,2-propane, Examples thereof include p- (4-hydroxyphenyl) phenol, oxybis (4-hydroxyphenyl), sulfonylbis (4-hydroxyphenyl), 4,4′-dihydroxybenzophenone, bis (2-hydroxynaphthyl) methane, and the like. Bis (4-hydroxyphenyl) methane Bisphenol F] and 2,2-bis (4-hydroxyphenyl) propane [bisphenol A] is preferable. The said bisphenol can be used individually by 1 type or in mixture of 2 or more types.

上記化学構造式中において、ｑは０〜５０の整数、好ましくは１〜４０の整数、特に好ましくは２〜２０の整数である。
このようなビスフェノールＡ型エポキシ樹脂は、当業界において広く知られた製造法により得ることができる。
ビスフェノール型エポキシ樹脂の市販品としては、例えば、ジャパンエポキシレジン（株）製のエピコート１００４、エピコート１００７、エピコート１０１０、エピコート１２５６、エピコート４２５０、エピコート４２７５（いずれも商品名）などを挙げることができる。 Particularly preferred as the epoxy group-containing resin (E) is a resin represented by the following chemical structural formula, which is a reactive product of bisphenol A and epihalohydrin, and is particularly suitable because of its excellent corrosion resistance.

In said chemical structural formula, q is an integer of 0-50, Preferably it is an integer of 1-40, Most preferably, it is an integer of 2-20.
Such a bisphenol A type epoxy resin can be obtained by a production method widely known in the art.
Examples of commercially available bisphenol-type epoxy resins include Epicoat 1004, Epicoat 1007, Epicoat 1010, Epicoat 1256, Epicoat 4250, Epicoat 4275 (all trade names) manufactured by Japan Epoxy Resin Co., Ltd., and the like.

As said modified | denatured epoxy resin, an acrylic modified epoxy resin, a polyester modified epoxy resin, a urethane modified epoxy resin etc. can be mentioned, for example. Also, a polyalkylene glycol-modified epoxy resin obtained by reacting polyalkylene glycol, polyisocyanate and an epoxy resin, or a modification obtained by reacting an epoxy resin with an active hydrogen-containing compound comprising a hydrazine derivative in which some or all of the compounds have active hydrogen. Epoxy resins (hydrazine derivative-modified epoxy resins) can also be used. Of these, hydrazine derivative-modified epoxy resins are particularly preferred from the standpoint of improving corrosion resistance.
The modified epoxy resin may be one in which various modifiers are reacted with the epoxy group or hydroxyl group in the epoxy resin, and includes, for example, an epoxy ester resin reacted with a dry oil fatty acid, acrylic acid or methacrylic acid, etc. Examples thereof include an epoxy acrylate resin modified with a polymerizable unsaturated monomer component and a urethane-modified epoxy resin reacted with an isocyanate compound.

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. .

  Modified by reacting an active hydrogen-containing compound (J) consisting of a hydrazine derivative (K) in which some or all of the compounds represented by the hydrazine derivative-modified epoxy resin have active hydrogen with an epoxy group-containing resin (E) The epoxy group-containing resin reacts with the hydrazine derivative (K) having active hydrogen to the epoxy group of the epoxy group-containing resin (E), thereby improving the adhesion with the base and forming a film with particularly excellent corrosion resistance. be able to.

Examples of the active hydrogen-containing compound (J) that reacts with the epoxy group of the epoxy group-containing resin (E) include those shown below, and one or more of these can be used. At least a part (preferably all) of the active hydrogen-containing compound (J) needs to be a hydrazine derivative (K) having active hydrogen. That is, among these, a hydrazine derivative (K) having active hydrogen is an essential component, and an active hydrogen-containing compound other than the hydrazine derivative (K) is used as necessary.
・ 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 (K) having active hydrogen include the following.
(A) 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;
(B) pyrazole compounds such as pyrazole, 3,5-dimethylpyrazole, 3-methyl-5-pyrazolone, 3-amino-5-methylpyrazole;

(C) 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;

(D) tetrazole compounds such as 5-phenyl-1,2,3,4-tetrazole and 5-mercapto-1-phenyl-1,2,3,4-tetrazole;
(E) thiadiazole compounds such as 5-amino-2-mercapto-1,3,4-thiadiazole, 2,5-dimercapto-1,3,4-thiadiazole;
(F) 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;
Of 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 part of the active hydrogen-containing compound (J) include the following.
(1) a primary amino group of an amine compound containing one secondary amino group and one or more primary amino groups, such as diethylenetriamine, hydroxyethylaminoethylamine, ethylaminoethylamine, methylaminopropylamine, etc .; A compound modified with aldimine, ketimine, oxazoline or imidazoline by heat reaction with aldehyde or carboxylic acid at a temperature of about 100 to 230 ° C., for example;

(2) Secondary monoamines such as diethylamine, diethanolamine, di-n- or -iso-propanolamine, N-methylethanolamine, N-ethylethanolamine;
(3) a secondary amine-containing compound obtained by adding a monoalkanolamine such as monoethanolamine and a dialkyl (meth) acrylamide by a Michael addition reaction;
(4) A compound obtained by modifying a primary amino group of an alkanolamine such as monoethanolamine, neopentanolamine, 2-aminopropanol, 3-aminopropanol, 2-hydroxy-2 '(aminopropoxy) ethyl ether to ketimine;

The quaternary chlorinating agent that can be used as a part of the active hydrogen-containing compound (J) is a hydrazine derivative or a tertiary amine that does not have active hydrogen and is not reactive with an epoxy group. 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 an epoxy group-containing resin (E) (preferably a high molecular weight epoxy group-containing resin) and an active hydrogen-containing compound (J) comprising a hydrazine derivative (K) in which some or all of the compounds have active hydrogen, It is obtained by reacting the epoxy group-containing resin (E) and the active hydrogen-containing compound (J) at 10 to 300 ° C., preferably 50 to 150 ° C. for about 1 to 8 hours.
This reaction may be performed by adding an organic solvent, 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, film-forming properties, and the like.

The blending ratio of the epoxy group-containing resin (E) (preferably a high molecular weight epoxy group-containing resin) and the active hydrogen-containing compound (J) comprising a hydrazine derivative (K) in which some or all of the compounds have active hydrogen is solid. It is desirable that the active hydrogen-containing compound (J) is 0.5 to 20 parts by mass, particularly preferably 1.0 to 10 parts by mass with respect to 100 parts by mass of the epoxy group-containing resin (E).
The blending ratio of the epoxy group-containing resin (E) and the active hydrogen-containing compound (J) is the number of active hydrogen groups in the active hydrogen-containing compound (J) and the number of epoxy groups in the epoxy group-containing resin (E). The ratio [number of active hydrogen groups / number of epoxy groups] is preferably 0.01 to 10, more preferably 0.1 to 8, and still more preferably 0.2 to 4, from the viewpoint of corrosion resistance.

The proportion of the hydrazine derivative (K) having active hydrogen in the active hydrogen-containing compound (J) is 10 to 100 mol%, more preferably 30 to 100 mol%, and still more preferably 40 to 100 mol%. Is appropriate. If the ratio of the hydrazine derivative (K) having active hydrogen is less than 10 mol%, the upper layer film cannot be provided with a sufficient rust prevention function, and the resulting rust prevention effect is obtained by simply mixing the film-forming organic resin and the hydrazine derivative. It is no different from the case of using it.
The epoxy group-containing resin (E) may be any of an organic solvent dissolution type, an organic solvent dispersion type, a water dissolution type, and a water dispersion type.

The urethane resin (F) contained in the upper layer coating composition is a product obtained by reacting a polyisocyanate compound with a polyhydroxy compound such as polyether diol or polyester diol. By blending the urethane group resin (F) together with the epoxy group-containing resin (E) into the upper layer coating composition, the corrosion resistance after processing can be effectively improved. This is because the film-forming property of the coating composition is improved by blending the urethane resin, so (1) the permeation-inhibiting action of the corrosion factor is improved, and (2) the elution of the anticorrosive additive component in the film is moderate. It is thought that this is because (3) the effect of suppressing cracking of the resin film after processing is obtained, and these contribute to the improvement of corrosion resistance.
The urethane resin is, for example, a polyisocyanate compound and a polyhydroxy compound in an excess of isocyanate groups relative to hydroxyl groups in the presence or absence of a hydrophilic organic solvent that does not have active hydrogen capable of reacting with isocyanate groups in the molecule. It can be easily obtained by reacting, and can be obtained by dissolving in the organic solvent if necessary.

Examples of the polyisocyanate compound include aliphatic diisocyanates such as hexamethylene diisocyanate and trimethylhexamethylene diisocyanate; cyclic aliphatic diisocyanates such as hydrogenated xylylene diisocyanate and isophorone diisocyanate; Examples include organic diisocyanates such as aromatic diisocyanates such as 4'-diphenylmethane diisocyanate, cyclized polymers of the above organic diisocyanates, and isocyanurates / biurets of the above organic diisocyanates.
The blending amount of the urethane resin (F) in the coating composition for the upper layer film is [epoxy group-containing resin (E) / urethane resin (F)] = 95 in terms of a solid mass ratio with the epoxy group-containing resin (E). / 5 to 5/95, preferably 75/25 to 25/75. If the blending amount of the urethane resin (F) is less than the above mass ratio, the effect of improving the post-processing corrosion resistance by blending the urethane resin is not sufficient. On the other hand, exceeding the above mass ratio is not preferable because the corrosion resistance deteriorates.

The coating composition for an upper layer film of the present invention contains an epoxy group-containing resin (E) and a urethane resin (F) as essential components, but reacts with the hydroxyl group in the epoxy group-containing resin and the urethane resin. By containing a curing agent that can be formed, the film is crosslinked at the time of heating and drying after coating, and a film having a dense barrier property with better workability can be formed. As a curing method for forming a resin composition film, a curing method using a urethanization reaction between a polyisocyanate compound (I) and an epoxy group-containing resin and a hydroxyl group in a urethane resin, an amino resin (H) and an epoxy group Preferred examples include a curing method that utilizes an etherification reaction between the containing resin and a hydroxyl group in the urethane resin.
Examples of the amino resin (H) include methylol obtained by reaction of an amino component such as melamine, urea, benzoguanamine, acetoguanamine, steroguanamine, spiroguanamine, and dicyandiamide with an aldehyde component such as formaldehyde, paraformaldehyde, acetaldehyde, and benzaldehyde. An amino acid resin is mentioned. Those obtained by etherifying the methylol group of this methylolated amino resin with a lower alcohol having 1 to 6 carbon atoms are also included in the amino resin.

Further, among the amino resins, a part or all of the methylol group of the methylol melamine resin is a methyl ether melamine resin etherified with methyl alcohol, a butyl ether melamine resin butyl etherified with butyl alcohol, or methyl alcohol. Particularly preferred is a mixed etherified melamine resin of methyl ether and butyl ether etherified with both of butyl alcohol. Among these, by using a methyl etherified melamine resin containing 1 or more, preferably 1.5 or more imino groups in one molecule, an epoxy group-containing resin (E) (preferably a high The low temperature reactivity with the molecular weight epoxy group-containing resin) and the urethane resin (F) is improved, and the toughness of the film can be greatly improved. Specific examples of commercially available products include, for example, Cymel 325, Cymel 327, Cymel 703 (all trade names) manufactured by Mitsui Cytec.
The above amino resins can be used individually by 1 type or in mixture of 2 or more types.

  Examples of the polyisocyanate compound (I) include aliphatic diisocyanates such as hexamethylene diisocyanate and trimethylhexamethylene diisocyanate; cyclic aliphatic diisocyanates such as hydrogenated xylylene diisocyanate and isophorone diisocyanate; Aromatic diisocyanates such as 4,4'-diphenylmethane diisocyanate; triphenylmethane-4,4 ', 4 "-triisocyanate, 1,3,5-triisocyanatobenzene, 2,4,6-tri Organic polyisocyanates such as polyisocyanate compounds having three or more isocyanate groups, such as isocyanatotoluene and 4,4'-dimethyldiphenylmethane-2,2 ', 5,5'-tetraisocyanate Itself, or an adduct of each of these organic polyisocyanates with a polyhydric alcohol, a low molecular weight polyester resin, water, or the like, or a cyclized polymer of each of the above organic polyisocyanates, and further an isocyanate biuret And so on.

  Furthermore, among them, the polyisocyanate compound having 4 or more, particularly preferably 6 to 10 isocyanate groups in one molecule can be used even when the reaction temperature is lowered, the epoxy group-containing resin (E) ( Preferably, a tough film can be formed by close cross-linking with the polymer epoxy group-containing resin), and the processed portion corrosion resistance when subjected to severe processing can be made particularly good. Examples of such a polyisocyanate compound include adducts of 4,4′-dimethyldiphenylmethane-2,2 ′, 5,5′-tetraisocyanate, adducts of hexamethylene diisocyanate, and the like.

The polyisocyanate compound (I) may be obtained by blocking a part or all of the isocyanate groups of the polyisocyanate compound with a blocking agent. Examples of the blocking agent include phenols such as phenol, cresol and xylenol; Lactams such as caprolactam, δ-valerolactam, γ-butyrolactam, β-propiolactam; methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, tert-butyl alcohol, ethylene glycol monoethyl Alcohols such as ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether, benzyl alcohol; formamide Oxime series such as shim, acetoaldoxime, acetoxime, methyl ethyl ketoxime, diacetyl monooxime, benzophenone oxime, cyclohexane oxime; active methylene series such as dimethyl malonate, diethyl malonate, ethyl acetoacetate, methyl acetoacetate, methyl acetoacetate, etc. A blocking agent can be mentioned.
Specific examples of commercial products of polyisocyanate compounds containing 4 or more isocyanate groups in one molecule include, for example, MF-B80M, MF-B60X, MF-K60X, ME20-B80S manufactured by Asahi Kasei Corporation (any Can also be mentioned.

As content of the said hardening | curing agent in the coating composition for upper layer membrane | film | coats, it is 1-50 mass in the ratio of solid content with respect to 100 mass parts of total solid content of epoxy-group-containing resin (E) and urethane resin (F). Part, preferably 5 to 30 parts by weight, is suitable from the viewpoint of curability.
The epoxy group-containing resin (E) 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.
In addition to the specific resin described above, for example, an acrylic resin, a polyester resin, an epoxy resin, an ethylene resin, an alkyd resin, a phenol resin, an olefin resin, etc. You may mix | blend 2 or more types by the ratio in the total resin solid content about 25 mass% as an upper limit.

The organometallic compound (G) contained in the upper layer coating composition is composed of one or more selected from an organic titanium compound, an organic zirconium compound, and an organoaluminum compound. These organometallic compounds are compounds in which organic groups consisting of atoms such as carbon, oxygen, nitrogen, sulfur, and phosphorus are bonded to any metal atom of titanium, zirconium, or aluminum. , (1) alkoxy type, (2) acylate type, and (3) chelate type (also known as coordinate type).
The reason why this organometallic compound (G) improves the corrosion resistance is not necessarily clear, but the barrier property against corrosion promoting factors such as oxygen and chloride ions is improved by increasing the crosslinkability and adhesion of the organic resin. It is thought that. In addition, when a non-chromium rust preventive additive is added in combination, it improves the dispersibility of the rust preventive additive in the film and improves the adhesion between the organic resin and the rust preventive additive. It is considered that the barrier property is further improved and the corrosion resistance is further improved.

As organic titanium compounds, Nippon Soda Co., Ltd. TST (alkoxy type), TBSTA (acylate type), T-60 (chelate type), Ajinomoto Fine Techno Co., Ltd. Preneact KR
TTS (acylate type), KR38S (chelate type), KR44 (chelate type), ORGATIX TA30 (alkoxy type), ORGATICS TPHS (acylate type), ORGATICS TC200 (chelate type) manufactured by Matsumoto Kosho Co., Ltd. ) And the like (all are trade names).

As organic zirconium compounds, Nippon Soda Co., Ltd. ZR-181 (chelate type), Matsumoto Kosho Co., Ltd. Olga Chicks ZA-60 (alkoxy type), Olga Chicks ZB-320 (acylate type), Olgatics ZC-550 (chelate type) and the like are mentioned (all are trade names).
Examples of the organoaluminum compound include Prenact AL-M (chelate type) manufactured by Ajinomoto Fine-Techno Co., Ltd., Olga-Tix AL-80 (acylate type) manufactured by Matsumoto Co., Ltd. Product name).

The structure of the organotitanium compound is as follows: the alkoxy type is Ti (OR) ₄ (R is an organic group), the acylate type is Ti (OR) _4-n (OCOR ′) _n , and the chelate type is Ti (OR) _4-n ( A) _n (A is a chelate compound). The structure of the organozirconium compound is as follows: the alkoxy type is Zr (OR) ₄ (R is an organic group), the acylate type is Zr (OR) _4-n (OCOR ′) _n , and the chelate type is Zr (OR) _{4− n} (A) _n (A is a chelate compound). The structure of the organoaluminum compound is Al (OR) ₃ (R is an organic group) for the alkoxy type, Al (OR) _3-n (OCOR ′) _{n for} the acylate type, and Al (OR) _{3− for the} chelate type. _n (A) _n (A is a chelate compound). Corrosion resistance varies depending on the difference in structure. As a result of examining each structure, it was found that the acylate type having an ester bond (—COO—) in the molecular structure exhibits the most excellent corrosion resistance. The reason why such an ester bond has excellent corrosion resistance is that a transesterification reaction with the hydroxyl group (—OH) of the organic resin is likely to occur, and the crosslinkability of the organic resin is increased compared to other structures, resulting in a barrier property. It is thought to improve.

  The compounding amount of the organometallic compound (G) in the upper layer coating composition is desirably 0.1 to 10 parts by mass with respect to 100 parts by mass of the resin solid content of the coating composition. If the compounding amount of the organometallic compound (G) is less than 0.1 parts by mass, the effect of improving the corrosion resistance is not sufficient. This is not preferable. From the viewpoint of corrosion resistance and composition viscosity, a more preferable blending amount is 0.5 to 5 parts by mass.

The upper layer film (coating composition for the upper layer film) of the present invention may contain a non-chromium rust preventive additive as needed for the purpose of improving the corrosion resistance. By including such a non-chromium-based anticorrosive additive in the upper layer film, more excellent anticorrosion performance can be obtained.
As this non-chromium rust preventive additive, it is particularly preferable to use one or more selected from the following (e1) to (e7).
(E1) Silicon oxide (e2) Calcium compound (e3) Slightly soluble phosphate compound (e4) Molybdate compound (e5) Vanadium compound (e6) Triazoles, thiols, thiadiazoles, thiazoles, thiurams One or more organic compounds containing S atoms (e7) One or more organic compounds containing N atoms selected from hydrazide compounds, pyrazole compounds, triazole compounds, tetrazole compounds, thiadiazole compounds, and pyridazine compounds The details and anticorrosion mechanism of the non-chromium-based anticorrosive additives (e1) to (e7) are as described above for the surface treatment film.

The compounding amount of the non-chromium rust preventive additive is 0.1 to 50 parts by mass, preferably 0.5 to 30 in terms of the solid content with respect to 100 parts by mass of the resin solid content of the coating composition for film formation. The mass part is appropriate. If the blending amount of this non-chromium rust preventive additive is less than 0.1 parts by mass, the effect of improving the corrosion resistance after alkali degreasing cannot be sufficiently obtained. This is not preferable because the corrosion resistance is deteriorated as well as the property.
Two or more rust preventive additives (e1) to (e7) may be added in combination, and 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 above component (e1), and one or more of the components (e3) to (e7), particularly preferably all of the components (e3) to (e7) are added to this. In particular, excellent corrosion resistance can be obtained.

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

In the upper layer coating (upper layer coating composition), if necessary, a solid lubricant can be blended for the purpose of improving the processability of the coating.
Examples of the solid lubricant applicable to the present invention include the following, and one or more of these can be used.
(1) Polyolefin wax, paraffin wax: For example, polyethylene wax, synthetic paraffin, natural paraffin, micro wax, chlorinated hydrocarbon, etc. (2) Fluorine resin fine particles: For example, polyfluoroethylene resin (polytetrafluoroethylene resin, etc.) In addition, fatty acid amide compounds (eg, 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, etc.) Etc.), graphite, fluorinated graphite, boron nitride, polyalkylene glycols may be used alone or in combinations of two or more such alkali metal sulfate.

Among the above solid lubricants, polyethylene wax and fluororesin fine particles (particularly, polytetrafluoroethylene resin fine particles) are preferable.
Examples of polyethylene wax include Hoechst's Celidust 9615A, Celidust 3715, Celidust 3620, Celidust 3910, Sanyo Chemical Co., Ltd. Sun Wax 131-P, Sun Wax 161-P, Mitsui Chemicals Chemipearl. W-100, Chemipearl W-200, Chemipearl W-500, Chemipearl W-800, Chemipearl W-950, etc. can be used (all are trade names).

The fluororesin fine particles are most preferably tetrafluoroethylene fine particles. For example, Lubron L-2 and Lubron L-5 manufactured by Daikin Industries, Ltd., MP1100 and MP1200 manufactured by Mitsui DuPont Co., Ltd., Asahi IC Fluoropolymers Co., Ltd. full-on dispersion AD1, full-on dispersion AD2, full-on L141J, full-on L150J, full-on L155J, etc. are suitable (all are trade names).
Among these, a particularly excellent lubricating effect can be expected by the combined use of polyolefin wax and tetrafluoroethylene fine particles.
The blending amount of the solid lubricant in the upper layer film is 1 to 30 parts by mass, preferably 1 to 10 parts by mass with respect to 100 parts by mass of the resin solid content of the coating composition for film formation. It is appropriate to do. If the blending amount of the solid lubricant is less than 1 part by mass, the lubricating effect is poor.

  The upper film (the upper film coating composition) of the surface-treated steel sheet of the present invention comprises an epoxy group-containing resin (E) (preferably a high molecular weight epoxy group-containing resin), a urethane resin (F), and an organometallic compound (G ) As an essential component, and a curing agent, a non-chromium anticorrosive additive, a solid lubricant, etc. are added to this as necessary. Further, if necessary, an organic color pigment (for example, condensation) is added as an additive. 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, thiols) Etc.), conductive pigments (eg, metal powders such as zinc, aluminum and nickel, iron phosphide, antimony-doped tin oxide, etc.), coupling agents (eg, silane couplings) , 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 epoxy group-containing resin (E) and the urethane resin (F) and can be prepared as a coating composition. Solvents can be used.
The neutralizing agent is blended as necessary to neutralize the epoxy group-containing resin (E) and / or the urethane resin (F) to make it water-based, and the epoxy group-containing resin (E) or When the urethane resin (F) is a cationic resin, an acid such as acetic acid, lactic acid or formic acid can be used as a neutralizing agent.

The dry film thickness of the upper layer film is 0.3 to 2.0 μm, preferably 0.4 to 1.5 μm. When the film thickness of the upper layer film is less than 0.3 μm, the corrosion resistance is insufficient. On the other hand, when the film thickness exceeds 2.0 μm, the weldability and the electrodeposition coating property are degraded.
Further, from the viewpoint of weldability and electrodeposition coating property, the total film thickness of the surface treatment film of the first layer and the upper film of the second layer is preferably 2.0 μm or less.

Next, the manufacturing method of the surface treatment steel plate of this invention is demonstrated.
In order to form the surface treatment film on the surface of the zinc-based plated steel sheet or the aluminum-based plated steel sheet, the 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. Apply and heat dry without rinsing.
As a method for forming the surface treatment composition on the surface of the plated steel sheet, any of a coating 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 150 ° 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 remains in the film, resulting in insufficient corrosion resistance. In addition, when the heating and drying temperature exceeds 150 ° C., not only is it uneconomical, but defects occur in the film and the corrosion resistance decreases. Moreover, since it becomes impossible to apply to a BH steel plate when heat drying temperature exceeds 150 degreeC, it is unpreferable.
An upper layer film (organic resin film) is formed as the second layer film on the upper layer of the surface treatment film formed as described above. The coating composition for the second layer film is applied to the surface-treated film surface so as to have the above-described film thickness, and is 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 150 ° 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 remains in the film, resulting in insufficient corrosion resistance. In addition, when the heating and drying temperature exceeds 150 ° C., not only is it uneconomical, but defects occur in the film and the corrosion resistance decreases. Moreover, since it becomes impossible to apply to a BH steel plate when heat drying temperature exceeds 150 degreeC, it is unpreferable.

Therefore, the manufacturing method of the surface treatment steel plate of this invention and its preferable embodiment are as follows.
[1] Apply a surface treatment composition containing the following components (a) to (c) to the surface of a zinc-based plated steel sheet or an aluminum-based plated steel sheet, and dry at a temperature of 30 to 150 ° C. To form a surface treatment film having a film thickness of 0.01 to 1.0 μm,
(A) a polyalkylene glycol-modified epoxy resin (A) obtained by reacting a polyalkylene glycol having a number average molecular weight of 400 to 20,000, a bisphenol type epoxy resin, an active hydrogen-containing compound and a polyisocyanate compound, and the polyalkylene glycol-modified A resin obtained by reacting an epoxy group-containing resin (B) other than the epoxy resin (A) with an active hydrogen-containing compound comprising a hydrazine derivative (C) in which some or all of the compounds have active hydrogen is used in water. Dispersed aqueous epoxy resin dispersion (b) Silane coupling agent: 1 to 300 parts by mass with respect to 100 parts by mass of the solid content of the aqueous epoxy resin dispersion (c) Phosphoric acid and / or hexafluorometal acid: 0.1 to 80 quality with respect to 100 parts by mass of the solid content of the aqueous epoxy resin dispersion Part The upper layer contains an epoxy group-containing resin (E), a urethane resin (F), and one or more organic metal compounds (G) selected from organic titanium compounds, organic zirconium compounds, and organic aluminum compounds. A high corrosion-resistant surface characterized in that an upper layer film is formed by applying a coating composition for an upper layer film and drying at a temperature of the ultimate plate temperature of 30 to 150 ° C. A method for producing a treated steel sheet.

[2] In the production method of [1] above, the epoxy group-containing resin (E) contained in the upper layer coating composition is a high molecular weight epoxy group-containing resin having a number average molecular weight of 6000 to 20000. A method for producing a highly corrosion-resistant surface-treated steel sheet.
[3] A highly corrosion-resistant surface in which the organometallic compound (G) contained in the coating composition for an upper layer film has an ester bond in its molecular structure in the production method of [1] or [2] A method for producing a treated steel sheet.
[4] In the production method according to any one of [1] to [3] above, the coating composition for the upper film is based on 100 parts by mass of the total solid content of the epoxy group-containing resin (E) and the urethane resin (F). And the manufacturing method of the highly corrosion-resistant surface-treated steel plate characterized by containing 0.1-10 mass parts of organometallic compounds (G).

[5] In the production method according to any one of [1] to [4], the surface treatment composition for forming a surface treatment film further comprises a water-soluble phosphate, and an aqueous epoxy resin dispersion of component (a). The manufacturing method of the highly corrosion-resistant surface-treated steel plate characterized by containing 0.1-60 mass parts of solid content with respect to 100 mass parts of solid content.
[6] In the production method according to any one of [1] to [5], the surface treatment composition for forming a surface treatment film further comprises a non-chromium rust preventive additive, and an aqueous epoxy resin dispersion of component (a) The manufacturing method of the highly corrosion-resistant surface-treated steel plate characterized by containing 0.1-50 mass parts in the ratio of solid content with respect to 100 mass parts of solid content of a liquid.
[7] In the production method according to any one of [1] to [6], the coating composition for the upper film further includes a non-chromium rust preventive additive with respect to 100 parts by mass of the resin solid content of the coating composition. The manufacturing method of the highly corrosion-resistant surface-treated steel plate characterized by containing 0.1-50 mass parts in the ratio of solid content.

[8] In the production method according to any one of [1] to [7], the surface treatment composition for forming the surface treatment film and / or the coating composition for the upper film is used as a non-chromium rust preventive additive as described below ( A method for producing a highly corrosion-resistant surface-treated steel sheet, comprising at least one selected from e1) to (e7).
(E1) Silicon oxide (e2) Calcium compound (e3) Slightly soluble phosphate compound (e4) Molybdate compound (e5) Vanadium compound (e6) Triazoles, thiols, thiadiazoles, thiazoles, thiurams One or more organic compounds containing S atoms (e7) One or more organic compounds containing N atoms selected from hydrazide compounds, pyrazole compounds, triazole compounds, tetrazole compounds, thiadiazole compounds, and pyridazine compounds

[9] In the production method according to any one of [1] to [8] above, the upper layer coating composition further comprises a curing agent having a group capable of crosslinking with a hydroxyl group, an epoxy group-containing resin (E) and a urethane resin ( A method for producing a highly corrosion-resistant surface-treated steel sheet, comprising 1 to 50 parts by mass of the solid content with respect to 100 parts by mass of the total solid content of F).
[10] The highly corrosion-resistant surface according to [9], wherein the curing agent having a group capable of crosslinking with a hydroxyl group is an amino resin (H) having an average of one or more imino groups in one molecule. A method for producing a treated steel sheet.
[11] The high corrosion resistance characterized in that in the production method of [9], the curing agent having a group capable of crosslinking with a hydroxyl group is a polyisocyanate compound (I) having an average of 4 or more isocyanate groups in one molecule. Manufacturing method of surface-treated steel sheet.

[12] A highly corrosion-resistant surface-treated steel sheet characterized in that, in the production method of [11], the polyisocyanate compound (I) is obtained by blocking at least part of isocyanate groups of the polyisocyanate compound with a blocking agent. Manufacturing method.
[13] In the production method of any one of [1] to [12] above, the epoxy group-containing resin (E) contained in the upper layer coating composition is a hydrazine derivative in which some or all of the compounds have active hydrogen. A method for producing a highly corrosion-resistant surface-treated steel sheet, which is a modified epoxy group-containing resin modified with an active hydrogen-containing compound (J) comprising (K).
[14] In the production method of any one of [1] to [13] above, the coating composition for the upper layer film further comprises a solid lubricant in a ratio of the solid content to 100 parts by mass of the resin solid content of the coating composition. The manufacturing method of the highly corrosion-resistant surface-treated steel plate characterized by containing 1-30 mass parts.

  In addition, the surface treatment film and the upper layer film described above 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 + upper layer film / no treatment, The surface treatment film + upper layer film / surface treatment film, surface treatment film + upper layer film / surface treatment film + upper layer film, and the like can be used.

  The surface treatment composition for forming the first layer uses a water-soluble or water-dispersible epoxy resin shown in Table 2 as a resin composition, and a silane coupling agent (Table 3), phosphoric acid or hexafluorometal acid ( Table 4), a water-soluble phosphate (Table 5), and a non-chromium rust preventive additive (Table 6) were appropriately blended, and the mixture was prepared by stirring for a predetermined time using a paint disperser (sand grinder).

The water-soluble or water-dispersible epoxy resin shown in Table 2 was produced as follows.
-Production of polyalkylene glycol-modified epoxy resin <Production Example 1>
To a glass four-necked flask equipped with a thermometer, stirrer and condenser, 1688 g of polyethylene glycol having a number average molecular weight of 4000 and 539 g of methyl ethyl ketone were added and stirred and mixed at 60 ° C., and then 171 g of tolylene diisocyanate was added. In addition, after reacting for 2 hours, Epicote 834X90 (epoxy resin, manufactured by Shell Japan, epoxy equivalent 250) 1121 g, 66 g of diethylene glycol ethyl ether and 1.1 g of 1% dibutyltin dilaurate solution were added, and further reacted for 2 hours. . Thereafter, the temperature was raised to 80 ° C. and reacted for 3 hours to confirm that the isocyanate value was 0.6 or less. Thereafter, the temperature was raised to 90 ° C., and methyl ethyl ketone was removed by distillation under reduced pressure until the solid content concentration reached 81.7%. After removal, 659 g of propylene glycol monomethyl ether and 270 g of deionized water were added and diluted to obtain a polyalkylene glycol-modified epoxy resin solution A1 having a solid concentration of 76%.

・ Production of aqueous epoxy resin dispersion <Production Example 2>
2029 g of EP1004 (epoxy resin, manufactured by Yuka Shell Epoxy Co., Ltd., epoxy equivalent 1000) and 697 g of propylene glycol monobutyl ether were charged into a four-necked flask, heated to 110 ° C., and completely dissolved in 1 hour. After 1180 g of the polyalkylene glycol-modified epoxy resin solution A1 obtained in Production Example 1 and 311.7 g of 3-amino-1,2,4-triazole (molecular weight 84) were added to this product and reacted at 100 ° C. for 5 hours. Then, 719.6 g of propylene glycol monobutyl ether was added to obtain a resin solution D1.
257.6 g of the above resin solution D1 was mixed with 50 g of MF-K60X (isocyanate curing agent, manufactured by Asahi Kasei Kogyo Co., Ltd.) and 0.3 g of Scat24 (curing catalyst), and after stirring well, 692.1 g of water was added dropwise little by little. Mixing and stirring were performed to obtain an aqueous epoxy resin dispersion E1.

<Production Example 3> (Aqueous epoxy resin dispersion containing no hydrazine derivative)
2029 g of EP1004 (epoxy resin, manufactured by Yuka Shell Epoxy Co., Ltd., epoxy equivalent 1000) and 697 g of propylene glycol monobutyl ether were charged into a four-necked flask, heated to 110 ° C., and completely dissolved in 1 hour. To this, 1180 g of the polyalkylene glycol-modified epoxy resin solution A1 obtained in Production Example 1 and 527.0 g of propylene glycol monobutyl ether were added to obtain a resin solution D2.
To 257.6 g of the above resin solution D2, 50 g of MF-K60X (isocyanate curing agent, manufactured by Asahi Kasei Kogyo Co., Ltd.) and 0.3 g of Scat24 (curing catalyst) were mixed and stirred well, and then 692.1 g of water was dropped and mixed little by little. The mixture was stirred to obtain an aqueous epoxy resin dispersion E2.

As the coating composition for forming the second layer, the resin compositions shown in Table 7 and Table 8 are used, and urethane resin (Table 9), organometallic compound (Table 10), and non-chromium rust preventive additive are added thereto. (Table 6) and a solid lubricant (Table 11) were appropriately blended and prepared by stirring for a predetermined time using a paint disperser (sand grinder).
The base resins (reaction products) of the resin compositions shown in Tables 7 and 8 were synthesized as follows.

<Synthesis Example 1>
Epicoat 828 (manufactured by Japan Epoxy Resin Co., Epoxy Equivalent 187), 634 parts of bisphenol A, 366 parts of bisphenol A, 8 parts of 50% tetraethylammonium bromide aqueous solution and 180 parts of cyclohexanone were charged into a four-necked flask and heated to 150 ° C. for 5 hours. After cooling, 300 parts of methyl isobutyl ketone and 1843 parts of cyclohexanone were added while cooling to obtain an epoxy resin solution F1 (resin composition (1)) having a solid content of 30%. The number average molecular weight of this resin was 7600.
<Synthesis Example 2>
347 parts of Epicoat 1256 (manufactured by Japan Epoxy Resin Co., Ltd., epoxy equivalent 7880) and 543 parts of cyclohexanone were charged into a four-necked flask, heated to 130 ° C., and the epoxy resin was completely dissolved in 2 hours. This was cooled to 120 ° C., 3.7 parts of 3-amino-1,2,4-triazole (molecular weight 84) was added and reacted for 6 hours until the epoxy group disappeared. 78 parts of ketone and 197 parts of cyclohexanone were added to obtain a triazole-modified epoxy resin solution F2 (resin composition (2)) having a solid content of 30%. The number average molecular weight of this resin was 10100.

<Synthesis Example 3>
Epicoat 828 (Japan Epoxy Resin, Epoxy Equivalent 187) 637 parts, bisphenol A 363 parts, 50% tetraethylammonium bromide aqueous solution 10 parts and cyclohexanone 175 parts were charged into a four-necked flask, heated to 160 ° C. and reacted for 4 hours. An epoxy resin solution with a solid content of 85% was obtained. To this, 1315 parts of cyclohexanone was added and then cooled to 100 ° C., 9.7 parts of 3,5-dimethylpyrazole and 13 parts of dibutylamine were added and reacted for 6 hours until the epoxy group disappeared, and then cooled. While adding 908 parts of methyl isobutyl ketone, pyrazole-modified epoxy resin solution F3 (resin composition (3)) having a solid content of 30% was obtained. The number average molecular weight of this resin was 6300.
<Synthesis Example 4>
Epicoat 828 (manufactured by Japan Epoxy Resin Co., Epoxy Equivalent 187), 1833 parts, 894 parts of bisphenol A, 1.96 parts of tetraethylammonium bromide and 294 parts of methyl isobutyl ketone were charged into a four-necked flask and heated to 140 ° C. for 4 hours. While reacting, 3795 parts of ethylene glycol monobutyl ether was added while cooling to obtain an epoxy resin solution F4 (resin composition (4)) having an epoxy equivalent of 1388 and a solid content of 40%. The number average molecular weight of this resin was 3100.

The plated steel sheet shown in Table 1, 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 plate | board thickness of the steel plate employ | adopted the thing of predetermined | prescribed plate | board thickness according to the objective of evaluation. After the surface of this plated steel sheet was subjected to alkali degreasing treatment, washed with water and dried, the surface treatment composition for forming the first layer was applied with a roll coater and dried by heating at various temperatures. The film thickness of the film was adjusted by the solid content (heating residue) of the surface treatment composition or coating conditions (roll rolling force, rotational speed, etc.).
Subsequently, the coating composition for forming the second layer was applied by a roll coater and dried by heating at various temperatures. The film thickness of the film was adjusted by the solid content (heating residue) of the coating composition or the coating conditions (rolling force of the roll, rotational speed, etc.).

Tables 12 to 23 show the results of evaluating the film composition and quality performance (corrosion resistance, post-processing corrosion resistance, weldability, electrodeposition coating property) of the obtained surface-treated steel sheet. The quality performance was evaluated as follows.
(1) Corrosion resistance About each sample, the following combined cycle test (CCT) was given, and it evaluated by the white rust generation | occurrence | production area rate and red rust generation | occurrence | production area rate after 63 cycles progress.
Salt spray (based on JIS Z 2371): 4 hours ↓
Dry (60 ° C): 2 hours ↓
Wet (50 ° C., 95% RH): 2 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 30% No red rust occurrence △: Red rust occurrence, red rust occurrence area ratio less than 10% ×: Red rust occurrence area ratio 10% or more

(2) Corrosion resistance after processing For each sample, deformation and sliding were added with a draw bead according to the following conditions, and this sample was used at 45 ° C. for 2 minutes using “FC-4460” manufactured by Nihon Parkerizing Co., Ltd. After degreasing under the conditions, the CCT performed in the above “(1) Corrosion resistance” was performed, and the white rust generation area ratio and the red rust generation area ratio after 45 cycles were evaluated.
Pressing load: 800kgf
Drawing speed: 1000mm / min
Bead shoulder R: Male side 2mmR, Female side 3mmR
Pushing depth: 7mm
Oil used: “Preton R-352L” manufactured by Sugimura Chemical Co., Ltd.
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 30% No red rust occurrence △: Red rust occurrence, red rust occurrence area ratio less than 10% ×: Red rust occurrence area ratio 10% or more

(3) Weldability With respect to each sample, a welding test with continuous spotting was performed under the conditions of using electrode: CF-type Cr—Cu electrode, applied pressure: 200 kgf, energizing time: 10 cycles / 50 Hz, welding current: 10 kA, and continuously hitting. 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 (4) Electrodeposition coating property Cationic electrodeposition paint (manufactured by Kansai Paint Co., Ltd.) After coating “GT-10”) to a film thickness of 30 μm, baking was performed at 130 ° C. for 30 minutes. The coated sample was immersed in boiling water for 2 hours, immediately cut in a grid pattern (10 × 10, 1 mm interval), attached and peeled with an adhesive tape, and the peeled area ratio of the coating film was measured. The evaluation criteria are as follows.
◎: No peeling ○: Peeling area ratio less than 5% △: Peeling area ratio of 5% or more, less than 20% ×: Peeling area ratio of 20% or more

In addition, * 1 to * 12 described in Tables 12 to 23 indicate the following contents.
* 1: No. described in Table 1. (Plated steel plate)
* 2: No. in Table 2 (Water-soluble or water-dispersible epoxy resin)
* 3: No. described in Table 3 (Silane coupling agent)
* 4: No. in Table 4 (Phosphoric acid or hexafluorometal acid)
* 5: No. in Table 5 (Water-soluble phosphate)
* 6: No. in Table 6 (Non-chromium rust preventive additive)
* 7: parts by mass * 8: No. in Table 7 and Table 8 (Resin composition)
* 9: No. in Table 9 (Urethane resin)
* 10: No. in Table 10 (Organic metal compound)
* 11: No. described in Table 11 (Solid lubricant)
* 12: parts by mass

Claims (16)

The film thickness formed by applying and drying a surface treatment composition containing the following components (a) to (c) on the surface of a zinc-based plated steel sheet or an aluminum-based plated steel sheet is 0.01 to 1.0 μm. Has a surface treatment film of
(A) a polyalkylene glycol-modified epoxy resin (A) obtained by reacting a polyalkylene glycol having a number average molecular weight of 400 to 20,000, a bisphenol type epoxy resin, an active hydrogen-containing compound and a polyisocyanate compound, and the polyalkylene glycol-modified A resin obtained by reacting an epoxy group-containing resin (B) other than the epoxy resin (A) with an active hydrogen-containing compound comprising a hydrazine derivative (C) in which some or all of the compounds have active hydrogen is used in water. Dispersed aqueous epoxy resin dispersion (b) Silane coupling agent: 1 to 300 parts by mass with respect to 100 parts by mass of the solid content of the aqueous epoxy resin dispersion (c) Phosphoric acid and / or hexafluorometal acid: 0.1 to 80 quality with respect to 100 parts by mass of the solid content of the aqueous epoxy resin dispersion Part The upper layer contains an epoxy group-containing resin (E), a urethane resin (F), and one or more organic metal compounds (G) selected from organic titanium compounds, organic zirconium compounds, and organic aluminum compounds. A highly corrosion-resistant surface-treated steel sheet, characterized by having an upper film having a film thickness of 0.3 to 2.0 μm formed by applying and drying a coating composition for an upper film.   The highly corrosion-resistant surface-treated steel sheet according to claim 1, wherein the epoxy group-containing resin (E) contained in the coating composition for the upper layer film is a high molecular weight epoxy group-containing resin having a number average molecular weight of 6,000 to 20,000. .   The highly corrosion-resistant surface-treated steel sheet according to claim 1 or 2, wherein the organometallic compound (G) contained in the coating composition for an upper layer film has an ester bond in its molecular structure.   The coating composition for the upper layer film contains 0.1 to 10 parts by mass of the organometallic compound (G) with respect to 100 parts by mass of the total solid content of the epoxy group-containing resin (E) and the urethane resin (F). The highly corrosion-resistant surface-treated steel sheet according to any one of claims 1 to 3.   The surface treatment composition for forming a surface treatment film further contains a water-soluble phosphate in an amount of 0.1 to 60 mass in terms of solid content with respect to 100 mass parts of solid content of the aqueous epoxy resin dispersion of component (a). The highly corrosion-resistant surface-treated steel sheet according to any one of claims 1 to 4, wherein the highly corrosion-resistant surface-treated steel sheet is contained.   The surface treatment composition for forming a surface treatment film further contains a non-chromium anticorrosive additive in a proportion of 0.1 to 100 parts by mass of the solid content of the aqueous epoxy resin dispersion of component (a). The highly corrosion-resistant surface-treated steel sheet according to any one of claims 1 to 5, comprising 50 parts by mass.   The upper layer coating composition further comprises 0.1 to 50 parts by mass of a non-chromium anticorrosive additive in a solid content ratio of 100 parts by mass of the resin solid content of the coating composition. The highly corrosion-resistant surface-treated steel sheet according to any one of claims 1 to 6. The surface treatment composition for forming the surface treatment film and / or the coating composition for the upper layer film contains at least one selected from the following (e1) to (e7) as a non-chromium rust preventive additive. The highly corrosion-resistant surface-treated steel sheet according to any one of claims 1 to 7.
(E1) Silicon oxide (e2) Calcium compound (e3) Slightly soluble phosphate compound (e4) Molybdate compound (e5) Vanadium compound (e6) Triazoles, thiols, thiadiazoles, thiazoles, thiurams One or more organic compounds containing S atoms (e7) One or more organic compounds containing N atoms selected from hydrazide compounds, pyrazole compounds, triazole compounds, tetrazole compounds, thiadiazole compounds, and pyridazine compounds   The coating composition for the upper layer film further contains a curing agent having a group that crosslinks with a hydroxyl group at a solid content ratio of 100 parts by mass of the total solid content of the epoxy group-containing resin (E) and the urethane resin (F). The highly corrosion-resistant surface-treated steel sheet according to any one of claims 1 to 8, wherein the steel sheet contains ~ 50 parts by mass.   The highly corrosion-resistant surface-treated steel sheet according to claim 9, wherein the curing agent having a group that crosslinks with a hydroxyl group is an amino resin (H) having one or more imino groups on average in one molecule.   The highly corrosion-resistant surface-treated steel sheet according to claim 9, wherein the curing agent having a group that crosslinks with a hydroxyl group is a polyisocyanate compound (I) having an average of 4 or more isocyanate groups in one molecule.   The high-corrosion-resistant surface-treated steel sheet according to claim 11, wherein the polyisocyanate compound (I) is obtained by blocking at least a part of isocyanate groups of the polyisocyanate compound with a blocking agent.   Modified epoxy groups in which the epoxy group-containing resin (E) contained in the upper layer coating composition is modified with an active hydrogen-containing compound (J) comprising a hydrazine derivative (K) in which some or all of the compounds have active hydrogen The highly corrosion-resistant surface-treated steel sheet according to any one of claims 1 to 12, which is a resin containing.   The coating composition for an upper film further contains 1 to 30 parts by mass of a solid lubricant in a ratio of solids to 100 parts by mass of resin solids of the coating composition. The high corrosion resistance surface-treated steel sheet according to any one of the above. The coating thickness is obtained by applying a surface treatment composition containing the following components (a) to (c) to the surface of a zinc-based plated steel sheet or an aluminum-based plated steel sheet, and drying at a temperature of an ultimate sheet temperature of 30 to 150 ° C. Forms a surface treatment film of 0.01 to 1.0 μm,
(A) a polyalkylene glycol-modified epoxy resin (A) obtained by reacting a polyalkylene glycol having a number average molecular weight of 400 to 20,000, a bisphenol type epoxy resin, an active hydrogen-containing compound and a polyisocyanate compound, and the polyalkylene glycol-modified A resin obtained by reacting an epoxy group-containing resin (B) other than the epoxy resin (A) with an active hydrogen-containing compound comprising a hydrazine derivative (C) in which some or all of the compounds have active hydrogen is used in water. Dispersed aqueous epoxy resin dispersion (b) Silane coupling agent: 1 to 300 parts by mass with respect to 100 parts by mass of the solid content of the aqueous epoxy resin dispersion (c) Phosphoric acid and / or hexafluorometal acid: 0.1 to 80 quality with respect to 100 parts by mass of the solid content of the aqueous epoxy resin dispersion Part The upper layer contains an epoxy group-containing resin (E), a urethane resin (F), and one or more organic metal compounds (G) selected from organic titanium compounds, organic zirconium compounds, and organic aluminum compounds. A high corrosion-resistant surface characterized in that an upper layer film is formed by applying a coating composition for an upper layer film and drying at a temperature of the ultimate plate temperature of 30 to 150 ° C. A method for producing a treated steel sheet.   The highly corrosion-resistant surface-treated steel sheet according to claim 15, wherein the epoxy group-containing resin (E) contained in the coating composition for the upper layer film is a high molecular weight epoxy group-containing resin having a number average molecular weight of 6000 to 20000. Manufacturing method.