JP2006176845A - Surface-treated steel sheet and manufacturing method thereof - Google Patents

Abstract

A surface-treated steel sheet excellent in corrosion resistance and blackening resistance is provided.
A first layer has a film containing an aqueous resin, a phosphoric acid compound, and a silane coupling agent on the surface of a zinc-based plated steel sheet and an aluminum-based plated steel sheet, and a second layer on the first layer forms a film. Reaction product (X) of organic resin (A) and active hydrogen-containing compound (B) comprising hydrazine derivative (C) in which some or all of the compounds have active hydrogen, ((a) phosphate, ( b) one or more organic compounds selected from Ca ion-exchanged silica, (c) molybdate, (d) silicon oxide, (e) triazoles, thiols, thiadiazoles, thiazoles, thiurams) Including one or more rust preventive additive components (Y) selected from the above, and the total content of the rust preventive additive components (Y) is 1 to 100 parts by mass (solid content) of the reaction product (X). 100 parts by mass (solid content) It has a certain film, the total thickness of the first layer and the second layer is 0.1 to 5 [mu] m.
[Selection figure] None

Description

  The present invention relates to a non-chromium-type surface-treated steel sheet for use in automobiles, home appliances, and building materials having white rust resistance and blackening resistance equivalent to hexavalent chromium without containing any harmful substances such as hexavalent chromium, and a method for producing the same. Is.

  Steel plates for home appliances, steel plates for building materials, and steel plates for automobiles have traditionally been made with chromic acid, for the purpose of improving corrosion resistance (white rust resistance, red rust resistance) on the surface of zinc-plated steel sheets or aluminum-plated steel sheets. Steel plates subjected to chromate treatment with a treatment liquid containing hexavalent chromium containing dichromic 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.

  However, since the chromate-treated coating contains hexavalent chromium, which is a pollution-controlling substance, it is stipulated that the use and release of hexavalent chromium is restricted, and there is a movement to reduce the use and emission of hexavalent chromium. Accelerating.

For this reason, many chromate-free treatment techniques have been proposed in place of the chromate treatment in order to prevent the occurrence of white rust in zinc-based plated steel sheets. For example, there is a method of forming a thin film by a method such as dipping, coating, or electrolytic treatment using an inorganic compound, an organic compound, an organic polymer material, or a solution combining these.
In particular,
(1) A method of forming a film with a treatment liquid containing an organic resin and a silane coupling agent (for example, Patent Document 1)
(2) A method in which an organic resin film containing a self-repairing rust preventive pigment is formed on the upper layer of the two-layer film, aiming at a protective film formation effect at the same corrosion starting point as hexavalent chromium (for example, Patent Document 2)
(3) Method of forming phosphoric acid and / or phosphoric acid compound film containing oxide in lower layer and organic resin film containing self-repairing rust preventive pigment on upper layer (for example, Patent Document 3 and Patent Document 4)
(4) A method of forming an organic resin film containing fine particle silica as an upper layer using a film containing an aqueous resin, a silane coupling agent and a phosphoric acid compound as a lower layer component (for example, Patent Document 5 and Patent Document 6)
JP-A-11-106945 Japanese Patent No. 3412538 JP 2002-53979 A JP 2002-53980 A JP 11-276987 A Japanese Patent No. 3477174

  However, these conventional techniques have the following problems.

Since the method (1) is a single layer film, it has a barrier effect in a chromate film: a barrier against corrosion factors (water, oxygen, chlorine, etc.) due to a trivalent chromium-based poorly soluble compound (hydrated oxide) Effect and self-repair effect: Since both effects of forming a protective film at the corrosion starting point due to hexavalent chromium cannot be fully exhibited, the same corrosion resistance as a chromate film cannot be obtained.

  The method (2) has an effect on the corrosion resistance by forming a two-layer film and adding a specific self-repairing substance to the upper layer, but the corrosion resistance is not sufficient only by the self-repair effect of the upper film. Yes, it is necessary to exhibit the barrier effect of the lower layer film.

  Further, in the method (3), as in the case (2), the corrosion resistance is improved to some extent by adding a specific self-repairing substance to the upper layer, but the adhesion between the lower complex oxide film and the upper film is improved. Therefore, the barrier effect of the corrosive factor is inferior, and a high degree of corrosion resistance cannot be obtained.

  The method (4) is inferior in corrosion resistance because it does not have a self-repairing effect, and is inferior in blackening resistance because the lower layer is treated with a highly reactive chemical.

  Blackening is a kind of initial corrosion of plated metal and is a phenomenon in which the entire steel sheet is blackened in a hot and humid environment. Suppression of change phenomenon) is required.

  Accordingly, an object of the present invention is to solve such problems of the prior art and provide a surface-treated steel sheet excellent in corrosion resistance and blackening resistance without containing a pollution control substance such as hexavalent chromium in the film. It is in.

As a result of intensive studies by the present inventors in order to solve the above problems, in order to develop corrosion resistance and blackening resistance equivalent to the chromate film, a plating metal in which the surface of the plating film is inactivated on the first layer and It was found that a two-layer structure comprising a high barrier layer serving as a diffusion barrier for corrosion factors in the reaction layer and the second layer is most effective. Furthermore, the first layer film is composed of a water-based resin, a phosphoric acid compound, and a silane coupling agent in a ratio within a specific range, and a specific chelate forming resin film is formed on the second layer film. ^It has excellent corrosion resistance by blending an appropriate amount of a specific self-repair developing substance instead of ⁶⁺ , and at the same time, by blending a metal compound of Co in the first layer film, especially corrosion resistance and black resistance after alkali degreasing. We found an excellent effect on denaturation.

The present invention has been made on the basis of such findings, and the features thereof are as follows.
[1] On the surface of a zinc-based plated steel sheet and an aluminum-based plated steel sheet, the first layer has a film containing an aqueous resin, a phosphoric acid compound, and a silane coupling agent, and the second layer on the first layer is a film-forming organic material A reaction product (X) of a resin (A) and an active hydrogen-containing compound (B) comprising a hydrazine derivative (C) in which some or all of the compounds have active hydrogen, and the following (a) to (e) 1 or more rust preventive additive component (Y) selected from the above, and the total content of the rust preventive additive component (Y) is 1 with respect to 100 parts by mass (solid content) of the reaction product (X). A surface-treated steel sheet having a film of ˜100 parts by mass (solid content), wherein the total thickness of the first layer and the second layer is 0.1 to 5 μm.

(A) Phosphate (b) Ca ion exchange silica (c) Molybdate (d) Silicon oxide (e) One or more kinds selected from triazoles, thiols, thiadiazoles, thiazoles, thiurams Organic compounds
[2] The first layer film contains 1 to 300 parts by mass of a silane coupling agent and 0.1 to 50 parts by mass of a phosphoric acid compound with respect to 100 parts by mass of the solid content of the aqueous resin. Surface treated steel sheet.
[3] The surface-treated steel sheet, wherein the first layer coating further contains 0.01 to 50 parts by mass of a Co metal compound with respect to 100 parts by mass of the solid content of the aqueous resin.
[4] A surface-treated steel sheet, wherein the reactive functional group of the silane coupling agent is an amino group.

[5] The surface-treated steel sheet, wherein the aqueous resin contains at least an epoxy resin.
[6] The surface-treated steel sheet, wherein the zinc-based plated steel sheet has a Ni content in the plating film of 20 to 1000 ppm or less.
[7] On the surface of the zinc-based plated steel sheet and the aluminum-based plated steel sheet, 1 to 300 parts by mass of the silane coupling agent and 0.1 to 0.1 parts of the phosphoric acid compound with respect to 100 parts by mass of the aqueous resin solid content as the first layer. By applying the surface treatment composition containing 50 parts by mass and drying at a temperature of the ultimate plate temperature of 30 to 300 ° C., a surface treatment film having a film thickness of 0.01 μm or more and less than 5 μm is formed,
On top of that, as a second layer, a reaction product (X) of a film-forming organic resin (A) and an active hydrogen-containing compound (B) comprising a hydrazine derivative (C) in which some or all of the compounds have active hydrogen And one or more rust preventive additive components (Y) selected from the following (a) to (e), and the total content of the rust preventive additive components (Y) is the reaction product (X ) By applying a surface treatment composition containing 1 to 100 parts by mass (solid content) to 100 parts by mass (solid content), and drying at a temperature of the ultimate plate temperature of 50 to 350 ° C., the film thickness is 0 Forming an organic film of 0.01 μm or more and less than 5 μm,
And the manufacturing method of the surface treatment steel plate characterized by the total film thickness of the said 1st layer and the said 2nd layer being 0.1-5 micrometers.

(A) Phosphate (b) Ca ion exchange silica (c) Molybdate (d) Silicon oxide (e) One or more kinds selected from triazoles, thiols, thiadiazoles, thiazoles, thiurams Organic compound [8] In the above [7], in the surface treatment composition applied when forming the first layer, a Co metal compound is further added in an amount of 0.01 to 100 parts by mass of the solid content of the aqueous resin. The manufacturing method of the surface-treated steel plate characterized by containing -50 mass parts.

  According to the present invention, it is possible to provide a surface-treated steel sheet excellent in corrosion resistance and blackening resistance, that is, a zinc-based plated steel sheet and an aluminum-based plated steel sheet. In addition, since the surface-treated steel sheet of the present invention does not contain pollution-controlling substances such as hexavalent chromium in the film, there is no environmental problem, and it is industrially used as a steel sheet for home appliances, a steel sheet for building materials, a steel sheet for automobiles, etc. It is beneficial.

  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 a galvanized steel sheet, a Zn-Ni plated steel sheet, a Zn-Fe plated steel sheet (electroplating, alloyed hot dip galvanizing), a Zn-Cr plated steel sheet, Zn -Mn plated steel sheet, Zn-Co plated steel sheet, Zn-Co-Cr alloy plated steel sheet, Zn-Cr-Ni plated steel sheet, Zn-Cr-Fe plated steel sheet, Zn-Al-Mg plated steel sheet (for example, Zn-6% Al -3% Mg alloy-plated steel sheet, Zn-11% Al-3% Mg alloy-plated steel sheet), Zn-Al plated steel sheet (for example, Zn-5% Al alloy-plated steel sheet, Zn-55% Al alloy-plated steel sheet) is used. It is possible. Further, these plated layers contain a small amount of different metal elements or impurities, such as nickel, cobalt, manganese, iron, molybdenum, tungsten, titanium, chromium, aluminum, magnesium, lead, antimony, tin, and copper, and / or silica. It is also possible to use a plated steel sheet (for example, a Zn—SiO 2 dispersion plated steel sheet) in which a metal oxide such as a polymer or a polymer is dispersed.

  Moreover, the multilayer plating steel plate which plated two or more layers of the same kind or different kind among the above plating can be used.

  As the aluminum-based plated steel sheet serving as the base of the surface-treated steel sheet of the present invention, an aluminum-plated steel sheet or an Al-Si plated steel sheet can be used.

  Moreover, as a plated steel plate, the steel plate surface may be plated in advance with a thin plate such as Ni, and the above-described various types of plating may be performed thereon.

  As a plating method, any feasible method among an electrolytic method (electrolysis in an aqueous solution, electrolysis in a non-aqueous solvent), a melting method, and a gas phase method can be employed.

  In addition, when the surface treatment film is formed on the surface of the plating film, alkali degreasing, solvent degreasing, surface adjustment treatment (alkaline surface adjustment) is performed on the plating film surface in advance as necessary so that film defects and unevenness do not occur. Treatment, acidic surface conditioning treatment) and the like can be performed. In addition, iron group metal ions (Ni ions, Co ions, Fe ions) are applied to the plating surface in advance as necessary to prevent blackening (a kind of oxidation phenomenon on the plating surface) under the usage environment of the organic coated steel sheet. Surface conditioning treatment with an acidic or alkaline aqueous solution containing can also be performed. When electrogalvanized steel sheet is used as the base steel sheet, iron group metal ions (Ni ions, Co ions, Fe ions) are added to the electroplating bath for the purpose of preventing blackening, and these metals are included in the plating film. Can be contained in an amount of 1 ppm or more. In this case, there is no particular limitation on the upper limit of the iron group metal concentration in the plating film.

  Next, the surface treatment film formed on the surface of the galvanized steel sheet will be described.

  In the surface-treated steel sheet of the present invention, the first layer 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 an aqueous resin, a phosphoric acid compound, and a silane coupling agent, It is a surface treatment film formed by drying.

  Here, the water-based resin includes a water-dispersible resin in which a water-insoluble resin such as an emulsion or a dispersion is dispersed in water in addition to a water-soluble resin. Examples of such a resin include an epoxy resin, a urethane resin, and an acrylic resin. Resin, acrylic silicon resin, acrylic-ethylene copolymer, acrylic-styrene copolymer, alkyd resin, polyester resin, ethylene resin, fluororesin, and the like can be used, and there is no particular limitation. However, from the viewpoint of corrosion resistance, it is preferable to use an organic polymer resin having an OH group and / or a COOH group, and among them, the epoxy resin can remarkably improve the adhesion between the base metal and the upper layer film, preferable.

  Next, the silane coupling agent will be described. 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 2 kinds or more. The reason why the film containing these silane coupling agents is excellent in corrosion resistance is that silanol groups (Si-OH) generated by hydrolysis of the silane coupling agent in the aqueous solution hydrogen bond with the surface of the plating film. It can be considered that excellent adhesion is imparted by a dehydration condensation reaction.

  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 having high adsorptivity with a plating metal. Examples of such silane coupling agents include N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ. -Aminopropyltrimexysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and the like, specifically, “KBM-903”, “KBE-903” manufactured by Shin-Etsu Chemical Co., Ltd., "KBM-603", "KBE-602", "KBE-603", etc. can be used.

  The amount of the silane coupling agent is preferably 1 to 300 parts by mass, more preferably 5 to 100 parts by mass, and still more preferably 15 to 50 parts by mass with respect to 100 parts by mass of the solid content of the aqueous resin. Is appropriate. If the blending 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 the effect of improving the adhesion and barrier properties with the water-dispersible resin cannot be exhibited. Corrosion resistance decreases.

Next, as the phosphoric acid compound, there is no limitation on the skeleton of the phosphate ion, the degree of condensation, etc., and hypophosphorous acid, phosphorous acid, orthophosphoric acid, polyphosphoric acid and salts thereof can be used. This phosphoric acid compound has an action of activating the metal surface by acting on the surface of the inactive plating film. And as a result of improving the adhesiveness of the plating metal surface activated in this way and film forming resin remarkably through a silane coupling agent, corrosion resistance is remarkably improved.
The amount of the phosphoric acid compound is preferably 0.1 to 50 parts by mass, more preferably 1 to 40 parts by mass, and even more preferably 5 to 30 parts by mass with respect to 100 parts by mass of the total solid content of the aqueous resin. Is appropriate. If the phosphoric acid compound is less than 0.1 parts by mass, the corrosion resistance is inferior. On the other hand, if it exceeds 50 parts by mass, the appearance unevenness after film formation tends to occur.

  For the purpose of improving the corrosion resistance after alkali degreasing and blackening resistance, the surface treatment composition for the first layer film is preferably further blended with a metal compound, more preferably Co. Examples of the Co supply source include Co nitrate, Co sulfate, and Co chloride, and one or more of these can be used. The reason why the corrosion resistance after alkali degreasing is improved by adding Co is considered to be because elution of the phosphoric acid compound as a component in the lower layer film is suppressed during alkali degreasing. In the corrosive environment, the phosphoric acid compound in the film becomes a phosphate ion and forms a protective film by causing a complex formation reaction with the eluted metal, thereby suppressing the elution of the phosphoric acid compound after alkaline degreasing, Excellent corrosion resistance even after alkaline degreasing.

  When blending Co, the blending amount of Co is 0.01 to 50 parts by weight, preferably 0.5 to 40 parts by weight, more preferably 1 to 100 parts by weight of the solid content of the aqueous resin. 30 parts by mass is appropriate. If the blending amount of Co is less than 0.01 parts by mass, the effect of improving the corrosion resistance is not sufficient. On the other hand, if it exceeds 50 parts by mass, the reactivity with the treatment liquid becomes strong and appearance unevenness tends to occur.

  Next, the organic film formed as the second layer film on the surface treatment film will be described.

  The organic film formed on the upper part of the first layer film is a reaction between the film-forming organic resin (A) and an active hydrogen-containing compound (B) composed of a hydrazine derivative (C) in which some or all of the compounds have active hydrogen. The product (X) and one or more rust preventive additives (Y) selected from the following (a) to (e) which are self-repairing substances are included (preferably, included as a main component) Is.

(A) Phosphate (b) Ca ion exchange silica (c) Molybdate (d) Silicon oxide (e) One or more kinds selected from triazoles, thiols, thiadiazoles, thiazoles, thiurams Organic compound As the type of the film-forming organic resin (A), a part or all of the compounds react with the active hydrogen-containing compound (B) comprising the hydrazine derivative (C) having active hydrogen, and are active on the film-forming organic resin. There is no particular limitation as long as the hydrogen-containing compound (B) is a resin that can be bonded by a reaction such as addition or condensation and can form a film appropriately. Examples of the film-forming organic resin (A) include epoxy resins, modified epoxy resins, polyurethane resins, polyester resins, alkyd resins, acrylic copolymer resins, polybutadiene resins, phenol resins, and adducts of these resins or A condensate etc. can be mentioned, One of these can be used individually or in mixture of 2 or more types.

  The film-forming organic resin (A) is particularly preferably an epoxy group-containing resin (D) containing an epoxy group in the resin from the viewpoints of reactivity, easiness of reaction, anticorrosion, and the like. As the epoxy group-containing resin (D), a part or all of the compounds react with the active hydrogen-containing compound (B) composed of the hydrazine derivative (C) having active hydrogen to form an active hydrogen-containing compound in the film-forming organic resin. There is no special limitation as long as (B) is a resin that can be bonded by a reaction such as addition or condensation and can form a film appropriately. For example, an acrylic resin copolymerized with an epoxy resin, a modified epoxy resin, an epoxy group-containing monomer Examples include copolymer resins, polybutadiene resins having an epoxy group, polyurethane resins having an epoxy group, and adducts or condensates of these resins. One of these epoxy group-containing resins may be used alone or in combination of two or more. Can be mixed and used.

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

  The epoxy resin is formed by introducing a glycidyl group by reacting a polyphenol such as bisphenol A, bisphenol F, or novolak type phenol with an epihalohydrin such as epichlorohydrin, or further adding a polyphenol to the glycidyl group-introduced reaction product. An aromatic epoxy resin obtained by reacting with an aromatic epoxy resin, an aliphatic epoxy resin, an alicyclic epoxy resin, and the like. These may be used alone or in admixture of two or more. Can do. These epoxy resins preferably have a number average molecular weight of 1500 or more, particularly when film formation at low temperatures is required.

  Examples of the modified epoxy resin include resins obtained by reacting various modifiers with epoxy groups or hydroxyl groups in the epoxy resin, such as epoxy ester resins, acrylic acid or methacrylic acid obtained by reacting a dry oil fatty acid. An epoxy acrylate resin modified with a polymerizable unsaturated monomer component containing styrene, a urethane-modified epoxy resin reacted with an isocyanate compound, and the like can be exemplified.

  As the acrylic copolymer resin copolymerized with the epoxy group-containing monomer, an unsaturated monomer having an epoxy group and a polymerizable unsaturated monomer component essentially comprising an acrylic ester or a methacrylic ester, a solution polymerization method, Examples thereof include resins synthesized by an emulsion polymerization method or a suspension polymerization method.

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

  The unsaturated monomer having an epoxy group is not particularly limited as long as it has an epoxy group and a polymerizable unsaturated group, such as glycidyl methacrylate, glycidyl acrylate, and 3,4-epoxycyclohexylmethyl (meth) acrylate. .

  The acrylic copolymer resin copolymerized with the epoxy group-containing monomer may be a resin modified with a polyester resin, an epoxy resin, a phenol resin, or the like.

  Particularly preferred as the epoxy resin is a resin having a chemical structure represented by the following formula (1), which is a reaction product of bisphenol A and epihalohydrin, and this epoxy resin is particularly preferable because of its excellent corrosion resistance.

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

  The film-forming organic resin (A) may be any of an organic solvent dissolution type, an organic solvent dispersion type, a water dissolution type, and a water dispersion type.

  The present invention aims to provide a hydrazine derivative in the molecule of the film-forming organic resin (A). Therefore, at least part (preferably all) of the active hydrogen-containing compound (B) is hydrazine having active hydrogen. It must be a derivative (C).

  In the case where the film-forming organic resin (A) is an epoxy group-containing resin, examples of the active hydrogen-containing compound (B) that reacts with the epoxy group include those shown below. In this case as well, at least a part (preferably all) of the active hydrogen-containing compound (B) needs to be a hydrazine derivative having active hydrogen.

・ Hydrazine derivatives with active hydrogen ・ Primary or secondary amine compounds with active hydrogen ・ Organic acids such as ammonia and carboxylic acids ・ Halogen halides such as hydrogen chloride ・ Alcohols and thiols ・ Having active hydrogen A hydrazine derivative or a quaternary chlorinating agent that is a mixture of a tertiary amine and an acid. Examples of the hydrazine derivative (C) having active hydrogen include the following.

(1) Carbohydrazide, propionic acid hydrazide, salicylic acid hydrazide, adipic acid dihydrazide, sebacic acid dihydrazide, dodecanoic acid dihydrazide, isophthalic acid dihydrazide, thiocarbohydrazide, 4,4'-oxybisbenzenesulfonyl hydrazide, benzophenone hydrazone, aminopolyacrylamide Hydrazide compounds such as;
(2) pyrazole compounds such as pyrazole, 3,5-dimethylpyrazole, 3-methyl-5-pyrazolone, 3-amino-5-methylpyrazole;
(3) 1,2,4-triazole, 3-amino-1,2,4-triazole, 4-amino-1,2,4-triazole, 3-mercapto-1,2,4-triazole, 5-amino -3-mercapto-1,2,4-triazole, 2,3-dihydro-3-oxo-1,2,4-triazole, 1H-benzotriazole, 1-hydroxybenzotriazole (monohydrate), 6- Triazole compounds such as methyl-8-hydroxytriazolopyridazine, 6-phenyl-8-hydroxytriazolopyridazine, 5-hydroxy-7-methyl-1,3,8-triazaindolizine;
(4) tetrazole compounds such as 5-phenyl-1,2,3,4-tetrazole and 5-mercapto-1-phenyl-1,2,3,4-tetrazole;
(5) thiadiazole compounds such as 5-amino-2-mercapto-1,3,4-thiadiazole and 2,5-dimercapto-1,3,4-thiadiazole;
(6) Maleic hydrazide, 6-methyl-3-pyridazone, 4,5-dichloro-3-pyridazone, 4,5-dibromo-3-pyridazone, 6-methyl-4,5-dihydro-3-pyridazone, etc. Pyridazine compounds Among these, pyrazole compounds and triazole compounds having a 5-membered or 6-membered ring structure and having a nitrogen atom in the ring structure are particularly suitable.

  These hydrazine derivatives can be used individually by 1 type or in mixture of 2 or more types.

  Typical examples of the amine compound having active hydrogen that can be used as part of the active hydrogen-containing compound (B) include the following.

(1) A primary amino group of an amine compound containing one secondary amino group and one or more primary amino groups, such as diethylenetriamine, hydroxyethylaminoethylamine, ethylaminoethylamine, and methylaminopropylamine, A compound modified with aldimine, ketimine, oxazoline or imidazoline by heat reaction with aldehyde or carboxylic acid at a temperature of about 100 to 230 ° C., for example;
(2) Secondary monoamines such as diethylamine, diethanolamine, di-n- or -iso-propanolamine, N-methylethanolamine, N-ethylethanolamine;
(3) a secondary amine-containing compound obtained by adding a monoalkanolamine such as monoethanolamine and a dialkyl (meth) acrylamide by a Michael addition reaction;
(4) A compound obtained by modifying the 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 (B) is a hydrazine derivative or a tertiary amine that does not have active hydrogen and is not reactive with an epoxy group by itself. In order to be able to react with the acid. A quaternary chlorinating agent reacts with an epoxy group in the presence of water as necessary to form a quaternary salt with an 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 (X) of the film-forming organic resin (A) and the active hydrogen-containing compound (B) composed of a hydrazine derivative (C) in which some or all of the compounds have active hydrogen is used as the film-forming organic resin (A). And an active hydrogen-containing compound (B) are obtained by reacting 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. 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-forming properties, and the like.

  The blending ratio between the film-forming organic resin (A) and the active hydrogen-containing compound (B) composed of a hydrazine derivative (C) in which some or all of the compounds have active hydrogen is a solid content ratio. ) The active hydrogen-containing compound (B) is preferably 0.5 to 20 parts by mass, particularly preferably 1.0 to 10 parts by mass with respect to 100 parts by mass.

  When the film-forming organic resin (A) is an epoxy group-containing resin (D), the blending ratio of the epoxy group-containing resin (D) and the active hydrogen-containing compound (B) is the active hydrogen-containing compound (B ) And the number of epoxy groups in the epoxy group-containing resin (D) [number of active hydrogen groups / number of epoxy groups] is 0.01 to 10, more preferably 0.1 to 8, and still more preferably. It is appropriate to set it to 0.2-4 from points, such as corrosion resistance.

  The proportion of the hydrazine derivative (C) having active hydrogen in the active hydrogen-containing compound (B) 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 (C) having active hydrogen is less than 10 mol%, the organic 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.

  In the present invention, in order to form a dense barrier film, it is desirable to mix a curing agent in the resin composition and heat cure the organic film.

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

  The polyisocyanate compound used in the curing method of (1) above is an aliphatic, alicyclic (including heterocyclic), or aromatic isocyanate compound having at least two isocyanate groups in one molecule, or many of these compounds. It is a compound that has been partially reacted with a monohydric alcohol. Examples of such polyisocyanate compounds include the following.

(i) m- or p-phenylene diisocyanate, 2,4- or 2,6-tolylene diisocyanate, o- or p-xylylene diisocyanate, hexamethylene diisocyanate, dimer acid diisocyanate, isophorone diisocyanate
(ii) The above compound (i) alone or a mixture thereof and a polyhydric alcohol (dihydric alcohols such as ethylene glycol and propylene glycol; trihydric alcohols such as glycerin and trimethylolpropane; tetrahydric alcohols such as pentaerythritol; A compound obtained by reaction with a hexahydric alcohol such as sorbitol and dipentaerythritol), in which at least two isocyanates remain in one molecule. These polyisocyanate compounds may be used alone or in combination of two or more. Can be used in combination.

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

  Such a polyisocyanate compound (E) is (A) / (E) = 95/5 to 55/45 (weight ratio of non-volatile content) with respect to the film-forming organic resin (A) as a curing agent, preferably ( It is suitable to mix | blend in the ratio of A) / (E) = 90 / 10-65 / 35. The polyisocyanate compound has water absorption, and if it is blended exceeding (A) / (E) = 55/45, the adhesion of the organic film may be deteriorated. Furthermore, when an overcoating is performed on the organic film, the unreacted polyisocyanate compound may move into the coating film, which may cause inhibition of curing of the coating film or poor adhesion. From such a viewpoint, the blending amount of the polyisocyanate compound (E) is preferably (A) / (E) = 55/45 or less.

  The film-forming organic resin (A) is sufficiently crosslinked by the addition of the crosslinking agent (curing agent) as described above, but it is desirable to use a known curing accelerating catalyst in order to further increase the low temperature crosslinking property. Examples of the curing accelerating catalyst include N-ethylmorpholine, dibutyltin dilaurate, cobalt naphthenate, stannous chloride, zinc naphthenate, and bismuth nitrate.

  For example, when an epoxy group-containing resin is used for the film-forming organic resin (A), a known acrylic, alkyd, polyester, or the like is mixed with the epoxy group-containing resin for the purpose of improving some physical properties such as adhesion. It can also be used.

  Next, the antirust additive component (Y) that is a self-repairing substance will be described.

  The phosphate which is the said component (a) contains all kinds of salts, such as a single salt and a double salt. Moreover, there is no limitation in the metal cation which comprises it, and any metal cation, such as zinc phosphate, magnesium phosphate, calcium phosphate, and aluminum phosphate, may be used. Further, there is no limitation on the skeleton or the degree of condensation of phosphate ions, and any of normal salt, dihydrogen salt, monohydrogen salt or phosphite may be used. In addition, orthophosphate may be polyphosphate other than orthophosphate. Includes all condensed phosphates such as salts.

  Moreover, corrosion resistance can further be improved by adding a calcium compound together with the phosphate which is the said component (a). The calcium compound may be any of calcium oxide, calcium hydroxide, and calcium salt, and one or more of these can be used. In addition, there are no particular restrictions on the type of calcium salt. In addition to simple salts containing only calcium as a cation such as calcium silicate, calcium carbonate, and calcium phosphate, calcium and calcium such as calcium phosphate / zinc, calcium phosphate / magnesium, etc. Double salts containing other cations may be used.

  Moreover, the Ca ion exchange silica which is said component (b) is what fixed the calcium ion on the surface of the porous silica gel powder, Ca ion is discharge | released in a corrosive environment, and forms a precipitation film | membrane.

  Any Ca ion-exchanged silica can be used, but those having an average particle size of 6 μm or less, preferably 4 μm or less are preferable, and for example, those having an average particle size of 2 to 4 μm can be used. When the average particle size of the Ca ion exchange silica exceeds 6 μm, the corrosion resistance is lowered and the dispersion stability in the coating composition is lowered.

  The Ca concentration in the Ca ion-exchanged silica is 1 wt% or more, desirably 2 to 8 wt%. When the Ca concentration is less than 1 wt%, the rust prevention effect due to Ca release cannot be sufficiently obtained. The surface area, pH, and oil absorption amount of the Ca ion exchange silica are not particularly limited.

  As the Ca ion exchange silica as described above, W.R.Grace & Co. SHIELDEX C303 (average particle size: 2.5 to 3.5 μm, Ca concentration: 3 wt%), SHIELDEX AC3 (average particle size: 2.3 to 3.1 μm, Ca concentration: 6 wt%), SHIELDEX AC5 (average particle size: 3. 8 to 5.2 μm, Ca concentration 6 wt%) (all are trade names), SHIELDEX (average particle diameter 3 μm, Ca concentration 6 to 8 wt%) manufactured by Fuji Silysia Chemical Ltd., SHIELDEX SY710 (average particle diameter 2) 0.2 to 2.5 μm, Ca concentration of 6.6 to 7.5 wt%) (all are trade names) and the like can be used.

  The molybdate that is the component (c) 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.

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

  In addition, when the solvent-based film forming resin is used as a base, for example, organosilica sol MA-ST-M, organosilica sol IPA-ST, organosilica sol EG-ST, organosilica sol E-ST manufactured by Nissan Chemical Industries, Ltd. -ZL, organosilica sol NPC-ST, organosilica sol DMAC-ST, organosilica sol DMAC-ST-ZL, organosilica sol XBA-ST, organosilica sol MIBK-ST (all are trade names), manufactured by Catalyst Kasei Kogyo Co., Ltd. OSCAL-1132, OSCAL-1232, OSCAL-1332, OSCAL-1432, OSCAL-1532, OSCAL-1632, OSCAL-1722 (all of which are trade names) can be used.

  In particular, the organic solvent-dispersed silica sol is excellent in dispersibility and superior in corrosion resistance than fumed silica.

  Examples of the fumed silica include AEROSIL R971, AEROSIL R812, AEROSIL R811, AEROSIL R974, AEROSIL R202, AEROSIL R805, AEROSIL 130, AEROSIL 200, AEROSIL 300, and more from AEROSIL 300CF manufactured by Nippon Aerosil Co., Ltd. Can also be used.

  The fine-particle silica contributes to the formation of a dense and stable zinc corrosion product in a corrosive environment, and the corrosion product is considered to be able to suppress the promotion of corrosion by being densely formed on the plating surface. It has been.

  From the viewpoint of corrosion resistance, it is preferable to use fine silica particles having a particle diameter of 5 to 50 nm, desirably 5 to 20 nm, more preferably 5 to 15 nm.

  Among the organic compounds of the component (e), triazoles include 1,2,4-triazole, 3-amino-1,2,4-triazole, 3-mercapto-1,2,4-triazole, 5- Amino-3-mercapto-1,2,4-triazole, 1H-benzotriazole, etc., and thiols include 1,3,5-triazine-2,4,6-trithiol, 2-mercaptobenzimidazole, etc. The thiadiazoles include 5-amino-2-mercapto-1,3,4-thiadiazole, 2,5-dimercapto-1,3,4-thiadiazole, and the thiazoles include 2-N, N -Diethylthiobenzothiazole, 2-mercaptobenzothiazole, etc., and thiurams include tetraethylthiuramdisulfur Such as soil, and the like, respectively.

  The total amount of the antirust additive component (Y) in the organic film (the total amount of one or more self-repairing substances selected from the components (a) to (e)) is: 1 to 100 parts by mass (solid content), preferably 5 to 80 parts by mass (solid content), more preferably 10 to 50 masses per 100 parts by mass (solid content) of the base resin (reaction product (X)) Parts (solid content). If the blending amount of the antirust additive component (Y) is less than 1 part by mass, the effect of improving corrosion resistance is small. On the other hand, if the blending amount exceeds 100 parts by mass, the corrosion resistance decreases, which is not preferable.

  The anticorrosion mechanism of the organic film that is the second layer film described above is considered as follows.

  In other words, by adding a hydrazine derivative to a film-forming organic resin rather than a simple low molecular weight chelating agent, (1) an effect of blocking corrosion factors such as oxygen and chlorine ions with a dense organic polymer film can be obtained. (2) The hydrazine derivative can be stably and firmly bonded to the surface of the first layer film to form a passivating layer. (3) Zinc ions eluted by the corrosion reaction can be removed by free hydrazine derivative groups in the film. In order to trap and form a stable insoluble chelate compound layer, the formation of an ion conductive layer at the interface is suppressed and the progress of corrosion is suppressed. It is considered that excellent corrosion resistance can be obtained.

  Further, when an epoxy group-containing resin is used as the film-forming organic resin (A), a dense barrier film is formed by the reaction between the epoxy group-containing resin and the crosslinking agent. It is excellent in the ability to suppress the permeation of factors, and an excellent bonding resistance to the substrate can be obtained by the hydroxyl group in the molecule, so that particularly excellent corrosion resistance (barrier property) can be obtained. Further, by using a pyrazole compound having active hydrogen or / and a triazole compound having active hydrogen as the hydrazine derivative (C) having active hydrogen, better corrosion resistance (barrier properties) can be obtained.

  As a conventional technique, a method of using a composition in which a hydrazine derivative is mixed with a film-forming organic resin is known. However, simply by mixing a hydrazine derivative with a film-forming organic resin as in this conventional technique, the effect of improving corrosion inhibition is achieved. Is almost unacceptable. The reason is considered to be that although the hydrazine derivative not incorporated in the molecule of the film-forming organic resin forms a chelate compound, the chelate compound does not form a dense barrier layer because of its low molecular weight. On the other hand, by incorporating a hydrazine derivative into the molecule of the film-forming organic resin as in the present invention, a remarkably excellent corrosion inhibiting effect can be obtained.

In the present invention, in the organic film composed of the specific organic polymer resin as described above,
(A) Phosphate (b) Ca ion exchange silica (c) Molybdate (d) Silicon oxide (e) One or more kinds selected from triazoles, thiols, thiadiazoles, thiazoles, thiurams A particularly excellent anticorrosion performance (self-healing effect) can be obtained by blending an appropriate amount of at least one rust-preventing additive (Y) (self-repairing substance) selected from organic compounds. The anticorrosion mechanism obtained by blending the components (a) to (e) in the specific organic film is considered as follows.

  First, the component (a) dissociates into phosphate ions by hydrolysis in a corrosive environment, and forms a protective film by causing a complexing reaction with the eluted metal.

In the case of the component (b), when a cation such as Na ion enters in a corrosive environment, Ca ions on the silica surface are released by an ion exchange action, and further, OH ions are generated by a cathodic reaction in the corrosive environment. When the pH in the vicinity of the plating interface increases and Ca ions released from the Ca ion exchange silica precipitate as Ca (OH) _{2 in the} vicinity of the plating interface, sealing defects as a dense and poorly soluble product, Inhibits corrosion reactions. Moreover, the eluted zinc ion is exchanged with Ca ion and the effect fixed on the silica surface is also considered.

  The component (c) exhibits self-repairing properties due to a passivating effect. That is, a dense oxide is formed on the surface of the plating film together with dissolved oxygen in a corrosive environment, and this inhibits the corrosion reaction by blocking the corrosion starting point.

  In addition, the component (d) contributes to the formation of a dense and stable zinc corrosion product in a corrosive environment, and the corrosion product is formed densely on the plating surface, thereby suppressing the promotion of corrosion. To do.

  The component (e) exhibits self-repairing properties due to the adsorption effect. That is, zinc and aluminum eluted by corrosion adsorb to the polar group containing nitrogen and sulfur contained in the component (e) to form an inactive film, which inhibits the corrosion reaction by blocking the corrosion starting point. .

  Even when the components (a) to (e) are blended in a general organic film, a certain degree of anticorrosion effect can be obtained, but an organic material having excellent barrier properties made of a specific organic polymer resin as in the present invention. By blending the above self-repairing substances (a) to (e) into the film, both effects (barrier property and self-repairing property) are combined, thereby exhibiting an extremely excellent anticorrosion effect. it is conceivable that.

  In addition, when a calcium compound is added together with the component (a) above, the calcium compound elutes preferentially over the plated metal in a corrosive environment, so that the phosphoric acid is not triggered by the elution of the plated metal. It causes a complexing reaction with ions to form a dense and sparingly soluble protective film to suppress the corrosion reaction.

  In addition, if two or more of the above-described components (a) to (e) are added in combination, the corrosion inhibiting action by each component is combined, so that more excellent corrosion resistance can be obtained.

  In addition to the above rust preventive additives, the organic film contains other oxide fine particles (eg, aluminum oxide, zirconium oxide, titanium oxide, cerium oxide, antimony oxide), phosphomolybdic acid as a corrosion inhibitor. Salts (for example, aluminum phosphomolybdate), organic phosphoric acid and its salts (for example, phytic acid, phytate, phosphonic acid, phosphonate, and metal salts thereof, alkali metal salts, alkaline earth metal salts, etc.) ), Organic inhibitors (for example, hydrazine derivatives, thiol compounds, dithiocarbamates, etc.) can be added.

  In the organic film, a solid lubricant (d) can be blended as necessary in order to improve the workability (scratch resistance) and continuous wear resistance of the film as required. As this lubricant, for example, fatty acid ester wax which is an esterified product of a polyol compound and a fatty acid, silicone wax, fluorine wax, polyolefin wax such as polyethylene, lanolin wax, montan wax, microcrystalline wax, carnauba wax, etc. There is no particular limitation. The lubricant can be used alone or in combination of two or more.

  The blending amount of the solid lubricant (d) in the organic film is a reaction product (film forming organic resin (A) and a hydrazine derivative in which some or all of the compounds have active hydrogen). (Reaction product with active hydrogen-containing compound (B) comprising (C)) 100 parts by weight (solid content), 1 to 80 parts by weight (solid content), preferably 3 to 40 parts by weight (solid content) And If the blending amount of the solid lubricant (d) is less than 1 part by weight, the lubricating effect is poor. On the other hand, if the blending amount exceeds 80 parts by weight, the paintability is unfavorable.

  The surface treatment film of the first layer formed of the surface treatment composition as described above has a dry film thickness of 0.01 μm to 5 μm, preferably 0.1 to 3 μm, more preferably 0.3 to 2 μm. Further, an organic resin film having a film thickness of 0.01 μm or more and less than 5 μm is formed as the second layer film on the upper layer of the surface treatment film described above. And the total film thickness of a 1st layer and a 2nd layer shall be 0.1-5 micrometers. If the total film thickness is less than 0.1 μm, the corrosion resistance is insufficient, while if it exceeds 5 μm, the conductivity decreases.

  Next, the manufacturing method of the surface treatment steel plate of this invention is demonstrated.

  The surface-treated steel sheet of the present invention treats the surface of a zinc-based plated steel sheet or an aluminum-based plated steel sheet with a treatment liquid containing the above-described aqueous resin, phosphoric acid compound, and silane coupling agent (applying the treatment liquid), and then heat-dried. Then, the reaction product (X) of the above-mentioned film-forming organic resin (A) and the active hydrogen-containing compound (B) comprising a hydrazine derivative (C) in which a part or all of the compounds have active hydrogen is formed thereon. And a rust preventive additive component (Y) (preferably as a main component), and further, a coating composition to which a solid lubricant or the like is added as necessary is applied and dried by heating.

  In addition, the surface of the plated steel sheet can be subjected to an alkali degreasing treatment as necessary before applying the treatment liquid, and further subjected to a pretreatment such as a surface adjustment treatment in order to improve adhesion and corrosion resistance.

  In order to form the first layer of the surface treatment film on the surface of the zinc-based plated steel sheet or the aluminum-based plated steel sheet, a treatment liquid having the above-described composition is applied to the plated steel sheet so that the dry film thickness is in the above range, and washed with water. Dry without heating.

  It is appropriate to adjust the surface treatment composition (treatment liquid) to pH 0.5-6, preferably 1-4. If the pH of the surface treatment composition is less than 0.5, the reactivity of the treatment solution is too strong, resulting in uneven appearance. Becomes insufficient, and the corrosion resistance decreases.

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 with a squeeze coater or the like, the dipping process, and 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, it is dried by heating without washing with water. As the heating and drying means, a dryer, a hot air furnace, a high frequency induction heating furnace, an infrared furnace or the like can be used. It is appropriate to perform the heat treatment in the range of 30 ° C. to 300 ° C., preferably 40 ° C. to 250 ° C., at the ultimate plate temperature. If this heating temperature is less than 30 ° C., a large amount of moisture remains in the film, resulting in insufficient corrosion resistance. Moreover, if it exceeds 300 degreeC, it will not only be uneconomical, but a defect will arise in a membrane | film | coat and corrosion resistance will fall.

  As described above, after the first layer of the surface treatment film is formed on the surface of the zinc-based plated steel sheet or the aluminum-based plated steel sheet, the treatment liquid for forming the organic film is applied to the upper layer. As a method for applying the coating composition, any method such as an application method, a dipping method, a spray method, or the like can be adopted. As a coating 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, dipping process or spraying process using a squeeze coater or the like, 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 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. The heat treatment is desirably performed in the range of 50 to 350 ° C., preferably 80 to 250 ° C., at the ultimate plate temperature. If the heating temperature is less than 50 ° C., a large amount of moisture remains in the film, resulting in insufficient corrosion resistance. Further, if the heating temperature exceeds 350 ° C., not only is it uneconomical, but there is a possibility that defects occur in the film and the corrosion resistance decreases.

  The above-mentioned surface treatment film may be formed on either one side or both sides of the plated steel sheet. As a combination of film formation on the front and back surfaces of the plated steel sheet, for example, a two-layer film (surface treatment film + organic resin film) / No treatment, two-layer coating (surface treatment coating + organic resin coating) / two-layer coating (surface treatment coating + organic resin coating), etc.

  Next, the present invention will be specifically described with reference to examples and comparative examples. In the following, “%” is based on mass.

  For forming the first layer film, a treatment liquid (aqueous solution) was prepared by appropriately blending the aqueous resin shown in Table 1, the silane coupling agent shown in Table 2, the phosphoric acid compound shown in Table 3, and the metal compound shown in Table 4. . Moreover, the coating composition which mix | blended suitably the antirust additive shown in Table 6 with base resin (1), (2) (Table 5) synthesize | combined as follows was prepared for 2nd layer membrane | film | coat formation.

[Synthesis Example 1]
EP828 (manufactured by Yuka Shell Epoxy Co., Epoxy Equivalent 187) 1870 parts, bisphenol A 912 parts, tetraethylammonium bromide 2 parts, methyl isobutyl ketone 300 parts are charged into a four-necked flask and heated to 140 ° C. and reacted for 4 hours. An epoxy resin having an epoxy equivalent of 1391 and a solid content of 90% was obtained. To this was added 1500 parts of ethylene glycol monobutyl ether and cooled to 100 ° C., 96 parts of 3,5-dimethylpyrazole (molecular weight 96) and 129 parts of dibutylamine (molecular weight 129) were added, and the epoxy group disappeared. After reacting for 6 hours, 205 parts of methyl isobutyl ketone was added while cooling to obtain a pyrazole-modified epoxy resin having a solid content of 60%. This is designated as base resin (1). This base resin (1) is a product of a film-forming organic resin (A) and an active hydrogen-containing compound containing 50 mol% of a hydrazine derivative (C) having active hydrogen.
[Synthesis Example 2]
4000 parts of EP1007 (manufactured by Yuka Shell Epoxy Co., Ltd., epoxy equivalent 2000) and 2239 parts of ethylene glycol monobutyl ether were charged into a four-necked flask and heated to 120 ° C. to completely dissolve the epoxy resin in 1 hour. This was cooled to 100 ° C., 168 parts of 3-amino-1,2,4-triazole (molecular weight 84) was added and reacted for 6 hours until the epoxy group disappeared, and then methyl isobutyl ketone 540 while cooling. A triazole-modified epoxy resin having a solid content of 60% was obtained. This is designated as base resin (2). This base resin (2) is a product of a film-forming organic resin (A) and an active hydrogen-containing compound containing 100 mol% of a hydrazine derivative (C) having active hydrogen.

  Using various plated steel sheets shown in Table 7 as the processing original plate, the surface of the plated steel sheet is treated with alkali degreasing, washed with water and dried, then treated (coated) with the treatment liquid for forming the first layer film, and dried at various temperatures. It was. Next, the coating composition for forming the second layer film was applied to the upper portion and dried at various temperatures to obtain surface-treated steel sheets of invention examples and comparative examples. In addition, the film thickness of the 1st layer and the 2nd layer membrane | film | coat was adjusted with the solid content (heating residue), processing time, etc. of the membrane | film | coat composition.

  The results of evaluating the quality performance (blackening resistance, corrosion resistance, conductivity) of the obtained surface-treated steel sheet are shown in Table 8 together with the test conditions and the film configuration. In addition, the measurement and evaluation method of each quality performance is as follows.

(1) Blackening resistance After each sample was allowed to stand for 1 day in an environment of 80 ° C. × 98% RH, it was evaluated by a color change ΔL (“L value after test” − “L value before test”). . The evaluation criteria are as follows.

A: ΔL ≧ −1
○: −1> ΔL ≧ −2
Δ: −2> ΔL ≧ −3
×: ΔL <−3
(2) White rust resistance About each sample, the salt spray test (JIS-Z-2371) was given and it evaluated by the white rust area rate after progress for 120 hours and 240 hours.
The evaluation criteria are as follows.

◎: White rust area ratio less than 5% ○: White rust area ratio 5% or more and less than 10% ○-: White rust area ratio 10% or more and less than 25% △: White rust area ratio 25% or more and less than 50% × : White rust area ratio 50% or more, 100% or less (3) White rust resistance after alkaline degreasing Each sample was subjected to a salt spray test (JIS-Z-2371) after alkaline degreasing, and white rust after 72 hours The area ratio was evaluated.
The evaluation criteria are as follows.

◎: White rust area ratio less than 5% ○: White rust area ratio 5% or more and less than 10% ○-: White rust area ratio 10% or more and less than 25% △: White rust area ratio 25% or more and less than 50% × : White rust area ratio 50% or more, 100% or less (4) Conductivity The interlayer insulation resistance value was measured according to JIS C2550. The evaluation criteria are as follows.

○: 3 Ω · cm 2 / sheet or less △: 3-5 Ω · cm 2 / sheet ×: 5 Ω · cm 2 / sheet Exceeded (5) Paint secondary adhesion Each sample was coated with a melamine-based baking paint (film thickness 30 μm). Then, it was immersed in boiling water for 2 hours, immediately cut a grid (10 × 10 pieces, 1 mm interval), attached and peeled with an adhesive tape, and measured the peeled area ratio of the coating film. The evaluation criteria are as follows.

◎: No peeling ○: Peeling area rate of less than 5% △: Peeling area rate of 5% or more and less than 20% X: Peeling area rate of 20% or more From Table 8, in the present invention example, blackening resistance, white rust resistance, The surface-treated steel sheet having excellent white corrosion resistance, electrical conductivity and paint secondary adhesion after alkali degreasing and excellent corrosion resistance and blackening resistance is obtained.

  On the other hand, in the comparative example, any one or more of blackening resistance, white rust resistance, white rust resistance after alkali degreasing, conductivity, and paint secondary adhesion is inferior.

  It is suitable for applications requiring excellent corrosion resistance and blackening resistance, mainly for steel sheets for home appliances, steel sheets for building materials, and steel sheets for automobiles.

Claims (8)

On the surface of galvanized steel sheet and aluminum-based galvanized steel sheet,
The first layer has a film containing an aqueous resin, a phosphoric acid compound, and a silane coupling agent, and the upper second layer has a film-forming organic resin (A) and some or all of the compounds have active hydrogen. A reaction product (X) with an active hydrogen-containing compound (B) comprising a hydrazine derivative (C), and one or more rust preventive additives (Y) selected from the following (a) to (e): Including a film having a total content of the anticorrosive additive (Y) of 1 to 100 parts by mass (solid content) with respect to 100 parts by mass (solid content) of the reaction product (X), The surface-treated steel sheet, wherein the total thickness of the first layer and the second layer is 0.1 to 5 μm.
(A) Phosphate (b) Ca ion exchange silica (c) Molybdate (d) Silicon oxide (e) One or more kinds selected from triazoles, thiols, thiadiazoles, thiazoles, thiurams Organic compounds   The said 1st layer membrane | film | coat contains 1-300 mass parts of silane coupling agents, and 0.1-50 mass parts of phosphoric acid compounds with respect to 100 mass parts of solid content of aqueous resin. The surface-treated steel sheet described in 1.   The surface-treated steel sheet according to claim 1 or 2, wherein the first layer film further contains 0.01 to 50 parts by mass of a Co metal compound with respect to 100 parts by mass of the solid content of the aqueous resin. .   The surface-treated steel sheet according to any one of claims 1 to 3, wherein the reactive functional group of the silane coupling agent is an amino group. The surface-treated steel sheet according to any one of claims 1 to 4, wherein the aqueous resin contains at least an epoxy resin.   The surface-treated steel sheet according to any one of claims 1 to 5, wherein the zinc-based plated steel sheet has a Ni content in the plating film of 20 to 1000 ppm or less. On the surface of galvanized steel sheet and aluminum-based galvanized steel sheet,
As the first layer, a surface treatment composition containing 1 to 300 parts by mass of the silane coupling agent and 0.1 to 50 parts by mass of the phosphoric acid compound is applied to 100 parts by mass of the solid content of the aqueous resin. By drying at a temperature at which the plate temperature becomes 30 to 300 ° C., a surface treatment film having a film thickness of 0.01 μm or more and less than 5 μm is formed,
On top of that, as a second layer, a reaction product (X) of a film-forming organic resin (A) and an active hydrogen-containing compound (B) comprising a hydrazine derivative (C) in which some or all of the compounds have active hydrogen And one or more rust preventive additive components (Y) selected from the following (a) to (e), and the total content of the rust preventive additive components (Y) is the reaction product (X ) Applying a surface treatment composition containing 1 to 100 parts by mass (solid content) to 100 parts by mass (solid content), and drying at a temperature at which the ultimate plate temperature is 50 to 350 ° C. Forming an organic film of 0.01 μm or more and less than 5 μm,
And the manufacturing method of the surface treatment steel plate characterized by the total film thickness of the said 1st layer and the said 2nd layer being 0.1-5 micrometers.
(A) Phosphate (b) Ca ion exchange silica (c) Molybdate (d) Silicon oxide (e) One or more kinds selected from triazoles, thiols, thiadiazoles, thiazoles, thiurams Organic compounds   The surface treatment composition to be applied when forming the surface treatment film as the first layer further contains a Co metal compound in an amount of 0.01 to 50 parts by mass with respect to 100 parts by mass of the solid content of the aqueous resin. The method for producing a surface-treated steel sheet according to claim 7.