JP2007009232A - Surface-treated steel sheet and manufacturing method thereof - Google Patents

Abstract

A surface-treated steel sheet excellent in corrosion resistance, water resistance, and scratch resistance and a method for producing the same are provided.
The surface of the steel sheet has a first layer film formed from a surface treatment composition containing an aqueous resin, a silane coupling agent having a mercapto group, and a phosphoric acid compound. Reaction product (X) of A) with an active hydrogen-containing compound (B) comprising a hydrazine derivative (C) in which some or all of the compounds have active hydrogen, (a) phosphate, (b) Ca Anti-rust additive (Y) selected from ion-exchange silica, (c) molybdate, (d) silicon oxide, (e) organic compounds selected from triazoles, thiols, and the like, and lubricant (Z) and a second layer film formed from a coating composition, and the particle diameter of the lubricant (Z) and the thickness of the second layer film are lubricant particle diameter / second layer film thickness. = 1.5 to 15 satisfied, the total of the first layer coating and the second layer coating Thickness, surface treated steel sheet is 0.1 to 5 [mu] m.
[Selection figure] None

Description

  The present invention is a non-chromium type surface-treated steel sheet having white rust resistance, water resistance and scratch resistance, which contains no harmful substances such as hexavalent chromium, and is suitable for applications such as automobiles, home appliances, and building materials. It relates to a manufacturing method.

  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-based 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, a film formed by chromate treatment is not preferable because it contains hexavalent chromium, which is a pollution control substance, and a surface-treated steel sheet that does not use hexavalent chromium is desired.

Furthermore, many of the surface-treated steel sheets are often processed and alkali degreased after processing and used as they are or after painting. Under such circumstances, recently, a method of omitting alkaline degreasing has been studied for the purpose of simplifying the process and reducing the cost. For example, as a steel sheet that can omit this degreasing step, a steel sheet having an organic resin film with good lubricity and wear resistance, and a steel sheet in which wax is added to the organic resin film have been developed and put to practical use. .
In particular,
(1) A method of forming a film in which a wax is dispersed in a urethane-based, acrylic-based, or polyester-based resin (Patent Document 1), or a water-based metal surface treatment that includes a urethane resin, a curing agent, silica, and a polyolefin wax. Method of forming a film with composition (Patent Document 2)
(2) A method of forming a film in which a polyvinylphenol derivative, a silane coupling agent, and a wax are blended (Patent Document 3)
(3) A method of forming an organic resin film containing a polyolefin wax dispersion 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 (Patent Document 4)
(4) 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 (Patent Document 5, Patent Document 6)
Is disclosed.
JP 2000-52478 A JP 2000-239690 A JP 2001-234350 A Japanese Patent No. 3464652 JP 2002-53979 A JP 2002-53980 A

However, the above prior art has the following problems.
Although the methods described in Patent Documents 1 and 2 (above (1)) have an effect on scratch resistance, they are steel sheets having a chromate treatment on the galvanized surface, so that they do not contain hexavalent chromium. The purpose of is not reached. Moreover, in the steel plate which carried out the zinc phosphate process on the zinc plating, although hexavalent chromium is not contained, corrosion resistance is inferior only by forming the said film | membrane on a zinc phosphate film | membrane.

  In the method described in Patent Literature 3 (above (2)), the film-forming resin is a phenolic resin, and the flexibility of the film is low. There is no description limiting the particle diameter of the wax added to the film, or the relationship between the softening point of the wax and the film drying temperature.

  The method described in Patent Document 4 (above (3)) has a great effect on scratch resistance by using a urethane resin having excellent abrasion resistance in addition to the polyolefin wax. Rust prevention effect by polyolefin wax is hardly seen, and it cannot be said that corrosion resistance is sufficient. Although it is a technique for obtaining corrosion resistance with the lower layer film, the phosphoric acid component necessary for obtaining corrosion resistance equivalent to the chromate film increases, and the phosphoric acid component remaining in the film absorbs water in a humid environment, so that the film becomes white. Water resistance is poor.

  Although the methods described in Patent Documents 5 and 6 (above (4)) add a specific self-repairing substance to the upper layer, they contribute to corrosion resistance in both the lower layer and the upper layer film, and are excellent in corrosion resistance. When the self-repairing substance-expressing particles protrude from the surface of the film, the scratch resistance is poor. Further, when the content is increased due to the influence of the lower phosphoric acid compound, the film is whitened, and the water resistance is not sufficient.

  In view of the above circumstances, the present invention provides a surface-treated steel sheet capable of achieving both corrosion resistance, water resistance, and scratch resistance without containing a pollution control substance such as hexavalent chromium in the film, and a method for producing the same. With the goal.

  As a result of intensive studies by the present inventors on the means for solving the above-mentioned problems, in order to achieve both excellent corrosion resistance, water resistance and wrinkle resistance, the surface layer of the plating film is deactivated on the first layer. An organic / inorganic composite layer, an organic film having strong adhesion to the first layer on the second layer, a rust preventive additive having self-repairability, and a two-layer film structure having lubricity are most effective. I found out. That is, the first layer film is formed of a surface treatment composition containing an aqueous resin, a phosphoric acid compound, and a silane coupling agent, and the second layer film is formed of an organic resin, a self-repairing substance, and a lubricant at a specific ratio. By forming the coating composition containing, and further controlling the particle diameter of the lubricant contained in the second layer film in the range of lubricant particle diameter / second layer film thickness = 1.5-15, It was found that the composite function as described above was exhibited, and excellent corrosion resistance, water resistance and wrinkle resistance were obtained. It has also been found that by adding a Co metal compound to the first layer coating, the corrosion resistance is further improved, and at the same time, blackening in a wet environment (a kind of oxidation phenomenon on the plating surface) is suppressed.

The present invention has been made based on such findings, and the features thereof are as follows.
[1] The surface of a zinc-based plated steel sheet or aluminum-based plated steel sheet contains an aqueous resin (I), a silane coupling agent (II) having a mercapto group, and a phosphoric acid compound (III), and the solid content of (I) The first layer film formed by applying and drying a surface treatment composition in which (II) is 1 to 300 parts by mass and (III) is 0.1 to 50 parts by mass with respect to 100 parts by mass. Furthermore, the reaction between the 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 on the first layer film. A product (X), one or more rust preventive additives (Y) selected from the following (a) to (e), and a lubricant (Z), wherein the reaction product (X) The total content of the rust preventive additive (Y) is 1 to 10 with respect to 100 parts by mass of the solid content. A second layer film formed by applying a coating composition having a content of 0.1 to 15 parts by mass and a lubricant (Z), and drying; and the lubricant (Z ) Satisfies the following formula, and the total film thickness of the first layer film and the second layer film is 0.1 to 5 μm. Surface treated steel sheet.

(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 lubricant particle diameter / second layer film thickness = 1.5-15
[2] In the above [1], the surface treatment composition for forming the first layer film further contains a Co 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. A surface-treated steel sheet.
[3] The surface-treated steel sheet according to any one of [1] or [2], wherein the aqueous resin contains an epoxy resin.
[4] The surface-treated steel sheet according to any one of [1] to [3], wherein the Ni content in the plating film is 20 to 1000 ppm or less.
[5] The surface of a zinc-based plated steel sheet or an aluminum-based plated steel sheet contains an aqueous resin (I), a silane coupling agent (II) having a mercapto group, and a phosphoric acid compound (III). The surface treatment composition (II) is 1 to 300 parts by mass and (III) is 0.1 to 50 parts by mass with respect to 100 parts by mass, and the first layer film is applied to the surface of the steel sheet by drying. And then, on top of the first layer film, a film-forming organic resin (A) and an active hydrogen-containing compound (B) consisting of a hydrazine derivative (C) in which some or all of the compounds have active hydrogen The reaction product (X) includes a reaction product (X), one or more rust preventive additives (Y) selected from the following (a) to (e), and a lubricant (Z). The total content of the anticorrosive additive (Y) is 1 to 100 parts by mass of the solid content of A second layer film formed by applying a coating composition having 00 parts by mass and a lubricant (Z) content of 0.1 to 15 parts by mass and drying at a temperature below the softening point of the lubricant. And the first layer coating and the second layer coating are formed so that the total thickness of the first layer coating and the second layer coating is 0.1 to 5 μm. A method of manufacturing a steel sheet.

(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

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the surface treatment steel plate excellent in corrosion resistance, water resistance, and wrinkle resistance. Further, the surface-treated steel sheet of the present invention has the above-mentioned performance and does not contain any harmful substances such as hexavalent chromium, so it can be said that it is an excellent material from the viewpoint of environment.

  The details of the present invention and the reasons for limitation will be described below.

The steel sheet used as the base of the surface-treated steel sheet of the present invention is a zinc-based plated steel sheet or an aluminum-based plated steel sheet.
As zinc-based plated steel sheets, galvanized steel sheets, Zn-Ni plated steel sheets, Zn-Fe plated steel sheets (electroplating, alloyed hot dip galvanizing), Zn-Cr plated steel sheets, Zn-Mn plated steel sheets, Zn-Co plated steel sheets 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). In addition, these plating layers contain one or more kinds of nickel, cobalt, manganese, iron, molybdenum, tungsten, titanium, chromium, aluminum, magnesium, lead, antimony, tin, and copper as small amounts of different metal elements or impurities. It is also possible to use a plated steel sheet and / or a plated steel sheet in which a metal oxide such as silica, a polymer, or the like is dispersed (for example, a Zn—SiO 2 dispersion plated steel sheet).
In addition, among the above-described plating, a multi-layer plated steel sheet in which two or more layers of the same type or different types are plated can also be used.

  Further, the galvanized steel sheet desirably contains 20 to 1000 ppm or less, more preferably about 25 to 800 ppm of Ni. Here, when the Ni content is 20 ppm or less, the blackening resistance is not sufficient. On the other hand, when the Ni content exceeds 1000 ppm, the color tone (L value) after the formation of the first layer and the second layer film is lowered, so that it is used without coating. If you do, it will not be suitable.

  Examples of the aluminum-based plated steel sheet include an aluminum-plated steel sheet and an Al—Si plated steel sheet.

  Moreover, as a plated steel plate, the steel plate surface may be pre-plated with light-weight plating such as Ni and the above-described various plating may be performed thereon. As a plating method, any feasible method among an electrolytic method (electrolysis in an aqueous solution, electrolysis in a non-aqueous solvent), a melting method, and a gas phase method can be employed.

  In addition, when the chemical conversion treatment film is formed on the surface of the plating film, in order to prevent film defects and unevenness, alkali degreasing, solvent degreasing, surface conditioning treatment (alkaline surface conditioning) is performed on the plating film surface in advance as necessary. It is also possible to perform a treatment such as a treatment or an acidic surface conditioning treatment. In addition, in order to prevent blackening (a kind of oxidation phenomenon of the plating surface) in the environment where the surface-treated steel sheet is used, iron group metal ions (Ni ions, Co ions, Fe ions) are applied to the plating surface in advance as necessary. Surface conditioning treatment with an acidic or alkaline aqueous solution containing one or more) can also be performed. When electrogalvanized steel sheet is used as the base steel sheet, iron group metal ions (one or more of Ni ions, Co ions, Fe ions) are added to the electroplating bath for the purpose of preventing blackening in the plating film. These metals 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 (first layer film) formed on the surface of the zinc-based plated steel sheet or the aluminum-based plated steel sheet and the surface treatment composition for forming this film will be described.
In the surface-treated steel sheet according to 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 a surface treatment composition containing a water-based resin, a silane coupling agent having a mercapto group, and a phosphate compound It is a surface treatment film formed by applying and drying.

Here, first, the aqueous resin will be described.
The aqueous resin includes a water-dispersible resin in which a water-insoluble resin is dispersed in water, such as an emulsion or a dispersion, in addition to a water-soluble resin. There are no particular restrictions on the water-based resin that can be used. For example, epoxy resin, urethane resin, acrylic resin, acrylic silicon resin, acrylic-ethylene copolymer, acrylic-styrene copolymer, alkyd resin, polyester resin, ethylene resin, fluorine resin Etc., and there are no special restrictions. 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, a silane coupling agent having a mercapto group will be described. Other silane coupling agents have functional groups such as a glycidyl group, an amino group, and a mercapto group. In terms of corrosion resistance, although any silane coupling agent is effective, a silane coupling agent having a mercapto group is particularly preferable from the viewpoint of having excellent water resistance. The reason why the corrosion resistance is excellent is that the silanol group (Si-OH) generated by the hydrolysis of the silane coupling agent in the aqueous solution can form hydrogen bonds with the surface of the plating film to give excellent adhesion. The effect of functional groups is small. However, in terms of water resistance, the influence of the functional group responsible for bonding with the resin is large, and a mercapto group having a higher binding strength is most excellent in water resistance. Examples of such silane coupling agents include γ-mercaptopropylmethyldimethoxysilane, γ-mercaptopropyltrimethoxysilane, and the like. Specifically, “KBM-802”, “Shin-Etsu Chemical Co., Ltd.” KBM-803 "or the like can be used. Moreover, these 1 type can be used individually or in mixture of 2 types, and it is also possible to use together with the silane coupling agent which has another functional group.

  The compounding amount of the silane coupling agent is 1 to 300 parts by mass, preferably 5 to 100 parts by mass, and more preferably 15 to 50 parts by mass with respect to 100 parts by mass of the total solid content of the aqueous resin. When the amount of the silane coupling agent is less than 1 part by mass, the water resistance is inferior. On the other hand, when the amount 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. Corrosion resistance decreases.

  Next, the phosphoric acid compound (d) will be described. As the phosphoric acid compound (d), there is no limitation on the skeleton of the phosphate ion or the degree of condensation, 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 improves notably.

  The compounding quantity of a phosphoric acid compound shall be 0.1-50 mass parts with respect to 100 mass parts of total solid of an aqueous resin, Preferably it is 1-40 mass parts, More preferably, you may be 5-30 mass parts. 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.

  Furthermore, in the present invention, it is preferable to add a Co compound to the surface treatment composition for the purpose of improving the corrosion resistance after alkali degreasing and the blackening resistance. 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.

  The blending amount of Co is 0.01 to 50 parts by mass, preferably 0.5 to 40 parts by mass, and more preferably 1 to 30 parts by mass with respect to 100 parts by mass of the solid content of the aqueous resin. 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 first layer film (surface treatment film) will be described.
The second layer film is a reaction product (X) of a 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, One or more rust preventive additive components (Y) selected from the following (a) to (e) and a lubricant (Z), and 100 parts by mass of the solid content of the reaction product (X) By applying a coating composition in which the total content of the anticorrosive additive component (Y) is 1 to 100 parts by mass and the content of the lubricant (Z) is 0.1 to 15 parts by mass and drying the coating composition It is an organic film to be formed.
(A) Phosphate (b) Ca ion exchange silica (c) Molybdate (d) Silicon oxide (e) One or more 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.

  In particular, as the film-forming organic resin (A), an epoxy group-containing resin (D) containing an epoxy group in the resin is particularly preferable from the viewpoints of reactivity, easiness of reaction, corrosion resistance, and the like. For example, 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 an adduct or condensate of these resins 1 type of these epoxy group containing resin can be used individually or in mixture of 2 or more types. Further, among these epoxy group-containing resins (D), epoxy resins and modified epoxy resins are particularly suitable from the viewpoints of adhesion to the plating surface and corrosion resistance. Thermosetting epoxy resins and modified epoxy resins that have excellent barrier properties against corrosion factors such as oxygen are optimal, and in particular, the coating amount is low to obtain high conductivity and spot weldability. This is particularly advantageous.

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

  Examples of the modified epoxy resin include resins obtained by reacting various modifiers with epoxy groups or hydroxyl groups in the epoxy resin, such as epoxy ester resins, 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.

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ている製造法を用いて製造することができる。また、上記化学構造式において、ｑは０〜５０、好ましくは１〜４０、特に好ましくは２〜２０である。

Such a bisphenol A type epoxy resin can be produced using a production method 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.

  In this invention, it aims at providing a hydrazine derivative in the molecule | numerator of film forming organic resin (A), and for this purpose, at least a part of the active hydrogen containing compound (B) reacted with the film forming organic resin (A) ( All preferably) are hydrazine derivatives (C) having active hydrogen.

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 acid ・ Halogen halides such as hydrogen chloride ・ Alcohols, Thiols ・ Active hydrogen A quaternary chlorinating agent that is a mixture of a hydrazine derivative or a tertiary amine and an acid that does not act. 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'-oxybisbenzenesulfonylhydrazide, benzophenone hydrazone, aminopolyacrylamide Hydrazide compounds such as
(2) Pyrazole compounds such as pyrazole, 3,5-dimethylpyrazole, 3-methyl-5-pyrazolone, 3-amino-5-methylpyrazole
(3) 1,2,4-triazole, 3-amino-1,2,4-triazole, 4-amino-1,2,4-triazole, 3-mercapto-1,2,4-triazole, 5-amino -3-mercapto-1,2,4-triazole, 2,3-dihydro-3-oxo-1,2,4-triazole, 1H-benzotriazole, 1-hydroxybenzotriazole (monohydrate), 6- Triazole compounds such as methyl-8-hydroxytriazolopyridazine, 6-phenyl-8-hydroxytriazolopyridazine, 5-hydroxy-7-methyl-1,3,8-triazaindolizine
(4) Tetrazole compounds such as 5-phenyl-1,2,3,4-tetrazole and 5-mercapto-1-phenyl-1,2,3,4-tetrazole
(5) Thiadiazole compounds such as 5-amino-2-mercapto-1,3,4-thiadiazole and 2,5-dimercapto-1,3,4-thiadiazole
(6) maleic hydrazide, 6-methyl-3-pyridazone, 4,5-dichloro-3-pyridazone, 4,5-dibromo-3-pyridazone, 6-methyl-4,5-dihydro-3-pyridazone, etc. Pyridazine compounds Among these, pyrazole compounds and triazole compounds having a 5-membered or 6-membered ring structure and having a nitrogen atom in the ring structure are particularly suitable.

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

Typical examples of the amine compound having active hydrogen that can be used as 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, Compound modified with aldemine, ketimine, oxazoline or imidazoline by heating reaction with aldehyde or carboxylic acid at a temperature of about 100 to 230 ° C.
(2) Secondary monoamines such as diethylamine, diethanolamine, di-n- or -iso-propanolamine, N-methylethanolamine, N-ethylethanolamine
(3) Secondary amine-containing compounds obtained by adding monoalkanolamines such as monoethanolamine and dialkyl (meth) acrylamides by Michael addition reaction
(4) Compounds obtained by modifying primary amino groups of alkanolamines such as monoethanolamine, neopentanolamine, 2-aminopropanol, 3-aminopropanol, 2-hydroxy-2 '(aminopropoxy) ethyl ether to ketimines As the quaternary chlorinating agent that can be used as a part of the hydrogen-containing compound (B), hydrazine derivatives or tertiary amines that do not have active hydrogen are not reactive with epoxy groups by themselves. 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 (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 converted into a film-forming organic resin (A ) And the active hydrogen-containing compound (B) 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, esters such as ethylene glycol monobutyl ether acetate, 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 (a dihydric alcohol such as ethylene glycol or propylene glycol, a trihydric alcohol such as glycerin or trimethylolpropane, a tetrahydric alcohol 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, octyl alcohol
(2) Ethylene glycol and / or diethylene glycol monoethers, for example, monoethers such as methyl, ethyl, propyl (n-, iso), butyl (n-, iso, sec)
(3) Aromatic alcohols such as phenol and cresol
(4) An oxime such as acetooxime or methyl ethyl ketone oxime can be used, and by reacting one or more of these with the polyisocyanate compound, a polyisocyanate compound that is 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 (mass ratio of non-volatile content), preferably (to the film-forming organic resin (A) as a curing agent. 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 antirust additive component (Y) is at least one selected from the following (a) to (e).
(A) Phosphate (b) Ca ion exchange silica (c) Molybdate (d) Silicon oxide (e) One or more selected from triazoles, thiols, thiadiazoles, thiazoles, thiurams Organic compound 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.

  The component (b), Ca ion-exchanged silica, is obtained by fixing calcium ions on the surface of the porous silica gel powder, and Ca ions are released in a corrosive environment to form a precipitated film.

  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: It is 1-100 mass parts with respect to 100 mass parts of solid content of base resin (reaction product (X)), Preferably it is 5-80 mass parts, More preferably, it is 10-50 mass parts. 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.

Furthermore, in the present invention, in the organic film composed of the specific organic polymer resin as described above,
A particularly excellent anticorrosion performance (self-healing effect) can be obtained by blending an appropriate amount of the above rust-preventing additive component (Y) (self-repairing substance). And the anticorrosion mechanism obtained by mix | blending the antirust addition component (Y) (self-repairable expression substance) in this specific organic membrane 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 cations such as Na ions enter in a corrosive environment, Ca ions on the surface of the silica 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 rises, Ca ions released from the Ca ion exchange silica precipitate as Ca (OH) ₂ near the plating interface, block defects as a dense and poorly soluble product, and cause a corrosion reaction. Suppress. Moreover, the eluted zinc ion is exchanged with Ca ion, and the effect fixed to 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.

  Further, in addition to the above-mentioned anticorrosive additives, other oxide fine particles (for example, aluminum oxide, zirconium oxide, titanium oxide, cerium oxide, antimony oxide, etc.), phosphomolybdic acid, and the like are added to the organic film 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 also be added.

Next, the lubricant (Z) added to improve the scratch resistance (workability) of the film will be described.
Examples of the lubricant (Z) include, for example, fatty acid ester waxes which are esterified products of polyol compounds and fatty acids, silicone waxes, fluorine waxes, polyolefin waxes such as polyethylene, lanolin waxes, montan waxes, microcrystalline waxes and carna Uba wax and the like can be mentioned. These lubricants (Z) can be used alone or in combination of two or more. The blending amount of the lubricant (Z) is 0.1 to 15 parts by mass, preferably 1 to 5 parts by mass with respect to 100 parts by mass of the solid content of the base resin (reaction product (X)). If the blending amount is less than 0.1 parts by mass, the scratch resistance (workability) is poor. On the other hand, if the blending amount exceeds 15 parts by mass, the paint adhesion decreases, which is not preferable.
Further, the particle diameter of the lubricant / the film thickness of the second layer = within a range of 1.5 to 15. When the particle diameter of the lubricant / the film thickness of the second layer exceeds 15, the lubricant peels off from the film when the film slides. If it is less than 1.5, the lubricant does not sufficiently protrude from the surface of the second layer film, so that the scratch resistance is lowered.
The softening point of the lubricant is preferably not less than the film drying temperature. When the softening point is lower than the film drying temperature, the lubricant melts and the original lubricity is not exhibited, so that the scratch resistance is lowered.

  The dry film thickness of the surface treatment film (first layer film) formed from the surface treatment composition obtained as described above is 0.01 μm to 5 μm, preferably 0.1 to 3 μm, more preferably 0.3 to 2 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 5 μm, the conductivity and workability deteriorate. The film thickness of the organic film (second layer film) is 0.01 μm or more and less than 5 μm, preferably 0.2 to 3 μm, more preferably 0.4 to 2 μm. If the film thickness is less than 0.01 μm, the lubricant is easily peeled off from the surface of the second layer film, so that the scratch resistance is insufficient. On the other hand, if it exceeds 5 μm, the conductivity decreases. Furthermore, the total of both coatings is preferably in the range of 0.1 to 5 μm from the viewpoint of conductivity.

Next, the manufacturing method of the surface treatment steel plate of this invention is demonstrated.
The surface-treated steel sheet of the present invention first forms a first layer film by applying and drying a surface treatment composition for forming a first layer film on the surface of a zinc-based plated steel sheet or an aluminum-based plated steel sheet, Next, a coating composition for forming the second layer film is applied to the upper portion, and the second layer film can be formed by drying at a temperature lower than the softening point of the lubricant. At this time, the surface treatment composition and the coating composition are applied so that the total film thickness of the first layer film and the second layer film is 0.1 to 5 μm.

  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.

  Thus, in order to form the first layer on the surface of the zinc-based plated steel sheet or the aluminum-based plated steel sheet, the 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 heated. dry. At this time, the surface treatment composition (treatment liquid) is preferably adjusted to pH 0.5 to 6, preferably 1 to 4. If the pH of the surface treatment composition is less than 0.5, the reactivity of the treatment liquid is too strong, resulting in uneven appearance. On the other hand, if the pH exceeds 6, the reactivity of the treatment liquid becomes low, and the bonding between the plating metal and the film is reduced. 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 using a squeeze coater or the like, the immersion 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, 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. The heat treatment is preferably 30 ° C to 300 ° C at the ultimate plate temperature. More preferably, it is 40 degreeC-250 degreeC. If it is less than 30 degreeC, the water | moisture content in a film | membrane will remain abundantly and corrosion resistance may become inadequate. Further, if it exceeds 300 ° C., it is not only uneconomical, but also defects may occur in the film, resulting in a decrease in corrosion resistance.

  After forming the surface treatment film (first layer film) on the surface of the zinc-based plated steel sheet or the aluminum-based plated steel sheet as described above, the coating composition for forming the second layer 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 performed at a temperature below the softening point of the lubricant. If the heating temperature exceeds the softening point of the lubricant, not only is it uneconomical, but there is a risk that the coating film will be defective and corrosion resistance will be reduced.

  Thus, the surface-treated steel sheet of the present invention is obtained. The first layer + second layer coating described above may be formed only on one side of the plated steel sheet or on both sides.

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 surface treatment composition was prepared by appropriately blending an aqueous resin shown in Table 1, a silane coupling agent shown in Table 2, a phosphoric acid compound shown in Table 3, and a metal compound shown in Table 4. For forming the second layer film, the base resins (1) and (2) (Table 5) synthesized as follows were appropriately blended with the rust preventive additive shown in Table 6 and the lubricant shown in Table 7. A coating composition was prepared.

［合成例１］
ＥＰ８２８（油化シェルエポキシ社製、エポキシ当量１８７）１８７０部とビスフェノールＡ９１２部、テトラエチルアンモニウムブロマイド２部、メチルイソブチルケトン３００部を四つ口フラスコに仕込み、１４０℃まで昇温して４時間反応させ、エポキシ当量１３９１、固形分９０％のエポキシ樹脂を得た。得られたエポキシ樹脂に対して、エチレングリコールモノブチルエーテル１５００部を加えてから１００℃に冷却し、３，５−ジメチルピラゾール（分子量９６）を９６部とジブチルアミン（分子量１２９）を１２９部加えて、エポキシ基が消失するまで６時間反応させた後、冷却しながらメチルイソブチルケトン２０５部を加えて、固形分６０％のピラゾール変性エポキシ樹脂を得た。これを基体樹脂（１）とする。この基体樹脂（１）は、皮膜形成有機樹脂（Ａ）と、活性水素を有するヒドラジン誘導体（Ｃ）を５０ｍｏｌ％含む活性水素含有化合物との生成物である。

[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 the obtained epoxy resin, 1500 parts of ethylene glycol monobutyl ether was added and then cooled to 100 ° C., 96 parts of 3,5-dimethylpyrazole (molecular weight 96) and 129 parts of dibutylamine (molecular weight 129) were added. The reaction was continued for 6 hours until the epoxy group disappeared, and then 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.
Next, using various plated steel sheets shown in Table 8 as the processing original plate, the surface of the plated steel sheet was subjected to alkaline degreasing treatment, washing with water and drying, and then the surface treatment composition for forming the first layer film was applied 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.

以上により得られた表面処理鋼板に対して品質性能（耐白錆性、耐黒変性、耐水性、耐疵つき性、塗料二次密着性）の各試験を行った。結果を表９に示す。なお、品質性能の試験条件及び評価基準は、以下の通りである。

Each test of quality performance (white rust resistance, blackening resistance, water resistance, scratch resistance, paint secondary adhesion) was performed on the surface-treated steel sheet obtained as described above. The results are shown in Table 9. The test conditions and evaluation criteria for quality performance are as follows.

(1) 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

(2) White rust resistance after alkaline degreasing For each sample, an alkaline degreasing material CLN-364S (manufactured by Nihon Parkerizing Co., Ltd.) was dissolved in pure water at a concentration of 20 g / l and heated to 60 ° C, and 1 kgf / After spraying for 2 minutes at a pressure of cm 2, a salt spray test (JIS-Z-2371) was performed, and the white rust area ratio after 120 hours 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

(3) Blackening resistance Each sample was allowed to stand for 1 day in an environment of 80 ° C. × 98% RH, and then 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

(4) Water resistance Each sample was immersed in pure water heated to 60 ° C. for 30 seconds in contact with the filter paper, and after taking out, the wet filter paper was left in contact with the steel plate for 90 seconds. Thereafter, the paper was removed, the moisture was wiped off, the sample surface was visually observed and evaluated according to the following criteria.
○: No whitening
Δ: Whitening that can be confirmed when viewed from an angle ×: Clear whitening (can be confirmed without viewing from an angle)

(5) After rubbing the test piece with corrugated cardboard using a rubbing resistance rubbing tester (produced by Taihei Rika Kogyo Co., Ltd.), the surface of the test piece was visually observed and evaluated according to the following evaluation. The test was performed at 500 g, a sliding distance of 60 mm, a speed of 120 mm / s, and a rubbing number of 1000 times.
◎: The number of cocoons is 0. ○: The number of cocoons is 1-2. △: The number of cocoons is 3-10. X: The number of cocoons is 11 or more.

(6) Paint secondary adhesion For each sample, after applying a melamine-based baking paint (film thickness 30 μm), it was immersed in boiling water for 2 hours, and immediately cut into a grid (10 × 10, 1 mm interval) The film was attached and peeled off 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 rate less than 5% △: Peeling area rate of 5% or more, less than 20%

表９より、本発明例はいずれの性能も優れていることがわかる。発明例３、７〜１５はベースめっき種を変更した結果であるが、いずれにおいても上記効果が得られており、特に、発明例３、１６〜１９は、下層皮膜の樹脂種を変更した結果であるが、この場合も同様に上記効果が得られている。また、発明例３、３３〜４０は上層樹脂種、防錆添加剤種を変更した結果であるが、いずれも優れた耐食性および耐水性、耐疵つき性が得られている。また、発明例３、２４〜２９では、下層皮膜の金属化合物の添加することによって、耐黒変性、アルカリ脱脂後耐白錆性に効果が見られ、特にＣｏを添加した場合にその効果が大きいことを示している。

From Table 9, it can be seen that the performance of the present invention is excellent. Invention Examples 3 and 7 to 15 are the results of changing the base plating type, but the above effects are obtained in all cases. In particular, Invention Examples 3 and 16 to 19 are the results of changing the resin type of the lower layer film. However, the above effect is obtained in this case as well. Inventive Examples 3, 33 to 40 are the results of changing the upper-layer resin type and the rust-preventive additive type, and all have excellent corrosion resistance, water resistance, and scratch resistance. In Invention Examples 3 and 24 to 29, the addition of the metal compound of the lower layer film is effective in blackening resistance and white rust resistance after alkaline degreasing, and particularly when Co is added. It is shown that.

  On the other hand, Comparative Examples 1, 9, and 10 are inferior in white rust resistance because any one of the lower layer aqueous resin, silane coupling agent, and phosphoric acid compound is not added.

  In Comparative Examples 3 to 8, water resistance is inferior because another silane coupling agent is used without using a silane coupling agent having a mercapto group within the scope of the present invention.

  In Comparative Examples 2 and 11, since the silane coupling agent or the phosphoric acid compound is excessively added outside the scope of the present invention, white rust resistance and water resistance are lowered.

  In Comparative Examples 13 and 14, since the rust preventive additive in the upper film is excessively added outside the scope of the present invention, the white rust resistance is lowered.

Inventive Examples 43 to 47 are the results of changing the type and particle size of the lubricant in the upper film, and all have excellent scratch resistance. On the other hand, in Comparative Examples 14 and 15 which are less than the lower limit and exceeds the upper limit of Formula A, the wrinkle resistance is lowered.
“Lubricant particle diameter / second layer film thickness = 1.5 to 15 Formula A
In Comparative Examples 20 and 21, since the addition amount of the lubricant is outside the range of the present invention, the scratch resistance and paint adhesion are deteriorated.

  In Comparative Examples 22 and 23, the film thickness of the upper layer or the lower layer is 0, that is, the film does not have a film, and therefore, corrosion resistance and wrinkle resistance are not compatible. That is, Invention Examples 3, 47 to 49 show the total film thickness effect of the lower layer and the upper layer, and as the total film thickness is larger, the corrosion resistance and the scratch resistance are improved. Further, it can be seen that the lower layer single film and the upper layer single film cannot achieve both corrosion resistance and scratch resistance, and it is important to use a two-layer film.

  Since the surface-treated steel sheet of the present invention is excellent in white rust resistance, blackening resistance, water resistance, scratch resistance, and paint adhesion, it is optimal as a steel sheet for home appliances, a steel sheet for building materials, and a steel sheet for automobiles. Of course, in addition to these, it can be used for applications where the steel sheet characteristics are required.

Claims (5)

On the surface of galvanized steel plate or aluminum galvanized steel plate,
The aqueous resin (I), the silane coupling agent (II) having a mercapto group (II), and the phosphoric acid compound (III) are contained, and (II) is 1 to 300 parts by mass relative to 100 parts by mass of (I) solid content, (III) It has the 1st layer membrane formed by applying and drying the surface treatment composition which is 0.1-50 mass parts,
Furthermore, on top of the first layer coating,
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;
One or more rust preventive additives (Y) selected from the following (a) to (e);
A lubricant (Z),
The total content of the rust preventive additive (Y) is 1 to 100 parts by mass and the content of the lubricant (Z) is 0.1 to 15 parts per 100 parts by mass of the solid content of the reaction product (X). Having a second layer film formed by applying and drying a coating composition that is part by mass;
And the relationship between the particle diameter of the lubricant (Z) and the thickness of the second layer film satisfies the following formula:
The surface-treated steel sheet, wherein a total film thickness of the first layer film and the second layer film 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 compound lubricant particle diameter / second layer film thickness = 1.5-15   2. The surface treatment composition for forming a first layer film further contains a Co 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. Surface treated steel sheet.   The surface-treated steel sheet according to claim 1, wherein the aqueous resin contains an epoxy resin.   The surface-treated steel sheet according to any one of claims 1 to 3, 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 plate or aluminum galvanized steel plate,
The aqueous resin (I), the silane coupling agent (II) having a mercapto group (II), and the phosphoric acid compound (III) are contained, and (II) is 1 to 300 parts by mass relative to 100 parts by mass of (I) solid content, (III) is applied to the surface treatment composition 0.1 to 50 parts by weight, and dried to form a first layer film on the surface of the steel sheet,
Next, on top of the first layer coating,
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;
One or more rust preventive additives (Y) selected from the following (a) to (e);
A lubricant (Z),
The total content of the anticorrosive additive (Y) is 1 to 100 parts by mass and the content of the lubricant (Z) is 0.1 to 15 with respect to 100 parts by mass of the solid content of the reaction product (X). Having a second layer film formed by applying a coating composition that is part by mass and drying at a temperature below the softening point of the lubricant;
And the 1st layer film and the 2nd layer film are formed so that the total film thickness of the 1st layer film and the 2nd layer film may be set to 0.1-5 micrometers, Manufacture of the surface treatment steel plate characterized by the above-mentioned Method.
(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