JPH0718461A - Surface treatment of zinc-aluminum alloy plated steel sheet, finishing agent and surfacetreated zinc-aluminum alloy plated steel sheet - Google Patents

Abstract

(57) [Summary] [Structure] The surface treatment method of the present invention comprises: an aqueous resin, a silicon compound represented by the following general formula; The surface treatment agent of the present invention containing a salt is applied to the surface of a zinc-aluminum alloy plated steel sheet. [Chemical 1] However, in the formula, R ¹ represents a hydroxyl group or a linear alkyl group having 1 to 10 carbon atoms, R ² and R ³ are hydrogen atoms,
It represents a hydroxyl group, an aryl group or a linear alkyl group having 1 to 10 carbon atoms, R ² and R ³ may be the same or different, and m represents 1 to 1,000. According to the present invention, an industrially advantageous zinc-aluminum alloy capable of preventing blackening of a zinc-aluminum alloy plated steel sheet, improving corrosion resistance and workability, and preventing leaching of chromium. A surface treatment method for a plated steel sheet and a surface treatment agent can be provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface treatment method for a zinc-aluminum alloy-plated steel sheet, a surface treatment agent and a surface-treated zinc-aluminum alloy-plated steel sheet. Can improve the corrosion resistance and workability,
Moreover, industrially advantageous surface treatment method of zinc-aluminum alloy plated steel sheet capable of preventing pollution, surface treatment agent used in the method, and using the surface treatment agent, by applying the surface treatment method, The present invention relates to a surface-treated zinc-aluminum alloy-plated steel sheet that does not cause blackening, does not easily rust, and does not easily cause desorption of a surface-treated film even when processed.

[0002]

2. Description of the Related Art In recent years, in a wide range of fields such as building materials such as roofing materials and wall materials, civil engineering materials such as soundproof walls, automobiles, home appliances and industrial equipment, corrosion resistance, especially The use of zinc-aluminum alloy-plated steel sheets, which have excellent corrosion resistance against salt damage, has been studied. This zinc-aluminum alloy-plated steel sheet is obtained by hot-dip-plating a zinc-aluminum alloy on the surface of the steel sheet. When this is used for a building member, for example, it is necessary to process it into a desired shape in advance.

However, the zinc-aluminum alloy-plated steel sheet contains aluminum, zinc, silicon, magnesium,
Since it has a plating layer consisting of trace components such as manganese and iron on the surface, it has poor surface lubricity and high hardness.

Therefore, when the zinc-aluminum alloy-plated steel sheet is subjected to roll forming, press working, etc., the forming roll and the press die are brought into contact with the plating layer under a high friction coefficient, so that the plating layer is destroyed. Sometimes. In this case, the plating powder adheres firmly to the molding roll and press die, causing flaws and abrasion on the molded product.
Occurs. Furthermore, if such molded products are stored,
There is a problem that the blackening progresses from the flaw portion and the commercial value decreases.

In the past, in order to solve these problems, a lubricant such as a lubricating oil or a wax is applied to the surface of a plating layer and a molding roll or a press die that comes into contact with the plating layer at the time of molding. It was

However, in this case, since the lubricant must be removed from the surface of the plated layer in the molded product after the molding process, the process becomes complicated.

Therefore, a surface treatment method or a surface treatment agent for a zinc-aluminum alloy-plated steel sheet, which can impart lubricity to the surface of the plating layer without applying a lubricant to the surface of the plating layer, is disclosed in, for example, Japanese Patent Laid-Open Publication No. 60-145383,
And JP-A-60-197881.

In JP-A-60-145383, an aqueous solution containing chromic acid or chromate or both of them and a water-soluble resin or emulsion resin or both of them is directly applied onto an aluminum-zinc composite plated steel sheet. And then dried to form a resin film having a film thickness after drying of 0.5 to 4 μm and a chromium content in the film of 5 to 50 mg / cm ^3. A post-treatment method for zinc composite plated steel sheet has been proposed.

However, this technique cannot obtain corrosion resistance unless a large amount of chromium is contained in the coating, and under conditions where good corrosion resistance can be obtained, the property installed on the roof or the like is not exposed to water due to rain or the like. In this case, chromium elutes from the property and the surface condition of the property deteriorates significantly.

Japanese Unexamined Patent Publication (Kokai) No. 60-197881 proposes a technique of applying a resin solution prepared by mixing a water-soluble resin or an emulsion resin with hexavalent chromium onto an aluminum-zinc alloy plated steel sheet.

However, even in this technique, unless a large amount of chromium is contained in the coating, the corrosion resistance cannot be obtained, and under the condition that good corrosion resistance can be obtained, the property installed on the roof or the like cannot be wetted by rain or the like. When this happens, chromium elutes from the property and the surface condition of the property deteriorates significantly.

The present invention solves the above problems, minimizes the content of hexavalent chromium, prevents blackening of zinc-aluminum alloy plated steel sheet, and improves corrosion resistance and workability. The surface treatment method of the above advantageous zinc-aluminum alloy plated steel sheet, the surface treatment agent suitably used for the surface treatment method, and the surface-treated zinc-aluminum alloy plated steel sheet obtained by such a surface treatment method. The purpose is to provide.

[0013]

The invention as set forth in claim 1 for solving the above-mentioned problems is characterized in that chromium is contained in an amount of 10 to 1 with respect to an aqueous resin, a silicon compound represented by the following general formula and the aqueous resin. A zinc-characterized by applying a surface treatment agent containing a hexavalent chromium salt in an amount of 500 ppm to the surface of a zinc-aluminum alloy-plated steel sheet.
It is a surface treatment method of an aluminum alloy plated steel sheet.

[0014]

[Chemical 1]

In the formula, R ¹ represents a hydroxyl group or a linear alkyl group having 1 to 10 carbon atoms, and R ² and R ³
Represents a hydroxyl group, an aryl group or a linear alkyl group having 1 to 10 carbon atoms, R ² and R ³ may be the same or different, and m represents 1 to 1,000.

The invention according to claim 2 is the surface treatment agent according to claim 1.

The invention according to claim 3 comprises an aqueous resin, a silicon compound represented by the following general formula, and a hexavalent chromium salt in an amount such that the ratio of chromium to the aqueous resin is 10 to 1,500 ppm. A surface-treated zinc-aluminum alloy-plated steel sheet, characterized in that the surface treatment agent is applied to the surface and dried.

In the surface treatment method for a zinc-aluminum alloy plated steel sheet according to the present invention, the surface treatment agent according to the present invention is applied to the surface of the zinc-aluminum alloy plated steel sheet.

The surface treatment agent according to the present invention contains chromium in an amount of 10 to 1 with respect to the aqueous resin, the silicon compound and the aqueous resin.
Hexavalent chromium salt is contained in an amount of 500 ppm.

Examples of the water-based resin include a water-soluble resin, a resin dispersed in water as an emulsion, and a resin suspended in water. Specific examples of the water-based resin include acrylic resin, polyester resin, polyethylene resin, polyvinyl resin, epoxy resin,
Butadiene-based resins, melamine-based resins, alkyd-based resins, phenol-based resins, and the like. Among these, acrylic resin can be mentioned as a preferable water-soluble resin.

Further, as the water-soluble resin, it is possible to use a coating containing any one of the above-mentioned various resins alone, or a coating containing any two or more of them. A preferred paint is an acrylic paint. By treating with the surface treatment agent of the present invention using an acrylic paint, a dense and uniform resin film can be formed on the surface of a zinc-aluminum alloy plated steel sheet, and as a result, for example, hexavalent chromium contained in this resin film. It is possible to prevent elution of ions, prevent contact between the zinc-aluminum alloy-plated steel sheet and the outside air, and improve corrosion resistance, blackening resistance, and lubricity.

This acrylic coating material is, for example, a methacrylic acid ester as a main component, and a thermoplastic acrylic resin obtained by copolymerizing this with various acrylic and vinyl monomers is dissolved in a solvent. Thermosetting acrylic paints prepared by dissolving a thermosetting acrylic resin obtained by reacting a plastic acrylic paint, acrylic acid ester, styrene, acrylamide, etc. with high heat and binding an aldehyde to the amide in this polymer in a solvent. be able to. Specific examples of the thermoplastic acrylic paint include solvent type thermoplastic acrylic resin paint, emulsion type acrylic resin paint, acrylic modified alkyd resin paint and the like.

The content of the aqueous resin in the acrylic paint is usually 20 to 60% by weight, preferably 25 to 50% by weight, more preferably 30 to 45% by weight. When the content of the water-based resin is within the above range, the surface treatment agent using an acrylic coating retains an appropriate viscosity and is excellent in coating workability.

The silicon compound in the surface treatment agent of the present invention is represented by the following general formula.

[0025]

[Chemical 1]

In the formula, R ¹ represents a hydroxyl group or a linear alkyl group having 1 to 10 carbon atoms, and R ² and R ³
Represents a hydroxyl group, an aryl group or a linear alkyl group having 1 to 10 carbon atoms, R ² and R ³ may be the same or different, and m represents 1 to 1,000.

Among the silicon compounds included in the above general formula, the silicon compounds represented by the following general formula are preferable.

[0028]

[Chemical 2]

However, R ⁴ represents a linear alkyl group having 1 to 10 carbon atoms, R ⁵ and R ⁶ represent a hydrogen atom, a methyl group or a phenyl group, and R ⁵ and R ⁶ are the same. May be different, and p and q are each 1 to
Represents 500.

The number average molecular weight of the silicon compound represented by the above general formula is preferably in the range of 500 to 150,000, and 2,000 to 100,000.
It is particularly preferable that it is within the range.

Examples of the silicone compound preferably used in the present invention include dimethyl silicone oil (number average molecular weight of about 5,000), dimethyl silicone oil (number average molecular weight of about 80,000) and methylphenyl silicone oil (number average molecular weight). Examples thereof include a molecular weight of about 8,000) and an alkyl-modified silicone oil (number average molecular weight of about 15,000).

The content of the silicon compound in this surface treatment agent is usually 1 to 10,000 with respect to the aqueous resin.
It is 0 ppm, preferably 10 to 5,000 ppm.
If the content of the silicon compound is less than 1 ppm, the effect of improving the corrosion resistance may be reduced.

The hexavalent chromium salt in the surface treating agent of the present invention is not particularly limited, and known compounds can be used, for example, chromic anhydride, strontium chromate, zinc chromate, sodium chromate,
Examples thereof include sodium dichromate, potassium chromate, potassium dichromate, calcium chromate, strontium chromate, ammonium chromate, ammonium dichromate and the like. Among these, sodium chromate and the like are preferable.

The content ratio of the hexavalent chromium salt is 1,500 ppm or less with respect to the aqueous resin, and 1
0-1,500 ppm is preferable, and further 20-1,2
00 ppm is preferred. The content ratio is 1,500 p
If it exceeds pm, the amount of hexavalent chromium ions to be eluted increases, which may adversely affect the environment.

The surface treatment agent according to the present invention is prepared by mixing the above-mentioned aqueous resin, the above-mentioned silicon compound and hexavalent chromium salt by a known method, for example, using a high speed stirrer, a sand grind mill, a ball mill or the like. It can be prepared.

In the surface treatment method for a zinc-aluminum alloy-plated steel sheet of the present invention, the surface-treating agent for the zinc-aluminum alloy-plated steel sheet obtained as described above is applied to the surface of the zinc-aluminum alloy-plated steel sheet, dry.

The zinc-aluminum alloy-plated steel sheet is not particularly limited in size, shape, etc., and one known per se can be used. The composition of the plating layer in the zinc-aluminum alloy plated steel sheet is usually 4-75% by weight of aluminum, most of the remainder is zinc, and preferably a material containing a small amount of silicon, magnesium, cerium, etc. You can

The coating can be carried out by a method known per se, for example, brush coating, tampo coating, spray coating, hot spray coating, air spray coating, electrostatic coating, roller coating, curtain flow coating, flow coating, dipping coating, electrodeposition. It can be performed by painting, spatula coating, or the like. In the present invention, it is preferable to remove stains such as fats and oils on the surface of the zinc-aluminum alloy plated steel sheet before the coating.

The thickness of the surface treatment agent applied to the surface of the plating layer of the zinc-aluminum alloy-plated steel sheet is preferably 0.5 to 4 μm, more preferably 1.0 to 4 μm.
3.0 μm is preferable. When the thickness exceeds 4 μm, corrosion resistance, blackening resistance, lubricity, etc. are improved, but weldability, solderability, etc. are deteriorated, which may be disadvantageous in terms of cost. On the other hand, if the thickness is less than 0.5 μm, no matter how the wettability of the surface treatment agent is improved, the surface treatment agent cannot be uniformly coated on the surface of the zinc-aluminum alloy plated steel sheet, resulting in corrosion resistance and blackening resistance. It may not be possible to improve.

The above-mentioned drying is performed by a device, an instrument, a device known per se,
For example, it can be performed using a dryer, a dryer, or the like. The drying temperature is a controlled plate temperature of 60 to 13
It is within the range of 0 ° C. The drying time is usually 3 seconds to 10 seconds.

The surface-treated zinc-aluminum alloy plated steel sheet of the present invention can be obtained by applying the above-mentioned surface treatment method to a zinc-aluminum alloy plated steel sheet. A coating film containing an aqueous resin, a silicon compound, and a hexavalent chromium salt constituting the surface treatment agent is formed in a thickness of 0.5 to 4 μm.

The surface-treated zinc-aluminum alloy-plated steel sheet of the present invention has a greatly reduced surface tension, has improved wettability, improved lubricity, and improved workability. In addition, the resin coating formed by the surface treatment agent of the present invention can reduce the amount of hexavalent chromium salt used and can significantly reduce the amount of hexavalent chromium ion eluted, which adversely affects the environment. There is no fear. Moreover, the resin film prevents the zinc-aluminum alloy plated steel sheet from coming into contact with outside air and moisture in the outside air, so that effectively prevents blackening of the zinc-aluminum alloy coated steel sheet and improves corrosion resistance. be able to.

According to the present invention, there is provided an industrially advantageous surface treatment method for a zinc-aluminum alloy plated steel sheet, a surface treatment agent, and a surface-treated zinc-aluminum alloy coated steel sheet, which have the above-mentioned excellent technical effects. You can

[0044]

【Example】

(Examples 1 to 16 and Comparative Examples 1 to 6) Various Al-Zn alloy plated steel sheets having different plating compositions were coated with the treatment liquid having the composition shown in Table 1 and then dried to obtain products.

The symbols in Table 1 have the following meanings.

<Material> GF: 5% Al-Zn alloy plated steel sheet GL: 55% Al-Zn alloy plated steel sheet <Type of silicone compound> A: Dimethyl silicone oil (average molecular weight: about 8, 000) B ... Dimethyl silicone oil (average molecular weight; about 5,000) C ... Diethyl silicone oil (average molecular weight; about 1,000) D ... Alkyl-modified silicone oil (average molecular weight;
About 15,000) <Type of hexavalent chromium compound> a ... Ammonium chromate b ... Ammonium dichromate c ... Astrontium chromate Corrosion resistance test, blackening resistance test, roll of the obtained product Moldability and direct paintability tests were conducted.

<Corrosion Resistance Test> A salt spray test was conducted in accordance with JIS Z2371. The size of the test piece is 70 ×
It was 150 mm and the test time was 240 hours. The test results were evaluated on the basis of the degree of white rust generation area by the following criteria and visually evaluated by 5 grades.

Evaluation value 5 ... White rust occurrence area 0% Evaluation value 4 ... White rust occurrence area 1 to 5% Evaluation value 3 ... White rust occurrence area 6 to 20% Evaluation value 2 ... White Rust generation area 21 to 30% Evaluation value 1 ... White rust generation area 30% or more.

<Black Deterioration Test> After cooling two test pieces to 5 ° C., they are placed in a room at 20 ° C. and 80% humidity to cause dew condensation on the surface of the test pieces, and immediately after that, two test pieces are tested. Wrap with vinyl-coated wrapping paper with the pieces facing each other and at 50 ° C while applying a pressure of 50 kgf / cm ^2.
The test was carried out for 240 hours on a wet tester having a humidity of 98%.

The judgment was evaluated by the change ΔL in the L value before and after the test. If ΔL is 5 or more, a problem occurs in practice, and the smaller ΔL is, the better the performance is.

<Blocking Test> Two test pieces (size: 10 × 10 cm) were put together in a constant temperature bath at 50 ° C. and 50
After testing a pressure of kg / cm ² for 48 hours, 2
The test pieces were peeled off and the degree of adhesion was evaluated according to the following criteria.

◯: No abnormality at all Δ: Test piece adheres easily and peels off ×: Test piece adheres and peels off, and a part of the film peels off.

<Roll Formability> A folded plate having a sectional shape shown in FIG. 1 was processed. The processing speed was 30 m / min and a test of 100 m was performed. The judgment was made based on the presence or absence of discoloration of the roll contact portion of the molded product and the presence or absence of adhesion of the plated metal to the roll.

Appearance of molded product ○ ・ ・ ・ No discoloration at roll contact part △ ・ ・ ・ Slight discoloration at roll contact part × ・ ・ ・ Clear discoloration at roll contact part Roll surface appearance ○ ・ ・ ・ No adhesion of plated metal Δ: Some adhesion of plating metal x: Plating metal seizes.

<Direct Paintability> An acrylic normally dry coating (Acryte No500, manufactured by NOF CORPORATION) was spray-coated on the test piece to a film thickness of 20 μm, and dried at room temperature for 49 hours. A cross-cut tape peeling test was performed and evaluated. The cross-cut tape peel test
100 squares of 1 mm square reaching the substrate were formed on the test piece with a cutter knife, and an adhesive tape (trade name: cellophane tape) was pressure-bonded to the surface, and evaluated by the number of coating films remaining after peeling.

<Chromium Elution Test> A test piece was cut into a 10 mm square, a surface area of 400 cm ² was immersed in 200 ml of pure water, heated to 60 ° C., and chromium was eluted for 2 hours. After that, the test piece was taken out, the solution was made acidic with hydrochloric acid, and one drop of a 1% diphenylcarbazide solution was dropped to examine the presence or absence of chromium. When the solution turns yellow, hexavalent chromium is present. It was judged according to the following criteria.

◯: No color developed at all Δ: Slight yellow color developed ×: Clear yellow color recognized

[0058]

[Table 1]

[0059]

[Table 2]

From the results of the above-mentioned tests, the surface treatment method of the Al--Zn alloy plated steel sheet according to the present invention has the conventional problems of corrosion resistance, blackening resistance and lubricity without leaching of chromium. This is a significantly improved technology.

[0061]

According to the present invention, an industrially advantageous zinc-aluminum alloy capable of preventing blackening of a zinc-aluminum alloy-plated steel sheet, improving corrosion resistance and workability, and preventing leaching of chromium. A surface treatment method for a plated steel sheet, a surface treatment agent, and a surface-treated zinc-aluminum alloy plated steel sheet can be provided.

[Brief description of drawings]

FIG. 1 is a sectional view showing a sectional shape of a folded plate obtained by processing a folded plate.

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] July 8, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0046

[Correction method] Change

[Correction content]

<Material> GF: 5% Al-Zn alloy plated steel sheet GL: 55% Al-Zn alloy plated steel sheet <Type of silicone compound> A: Dimethyl silicone oil (average molecular weight: about 8, 000) B ... Dimethyl silicone oil (average molecular weight; about 5,000) C ... Diethyl silicone oil (average molecular weight; about 1,000) D ... Alkyl-modified silicone oil (average molecular weight;
Approximately 15,000) <Type of hexavalent chromium compound> a ... Ammonium chromate b ... Ammonium dichromate c ... Strontium chromate Corrosion resistance test, blackening resistance test, roll forming And direct paintability were tested. ─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] January 19, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 1

[Correction method] Change

[Correction content]

[Chemical 1] However, in the formula, R ¹ represents a hydroxyl group or a linear alkyl group having 1 to 10 carbon atoms, R ² and R ³ are hydrogen atoms,
It represents a hydroxyl group, an aryl group or a linear alkyl group having 1 to 10 carbon atoms, R ² and R ³ may be the same or different, and m represents 1 to 1,000.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 3

[Correction method] Change

[Correction content]

[Chemical 1] However, in the formula, R ¹ is a hydroxyl group or has 1 to 10 carbon atoms.
Represents a straight chain alkyl group, R ² and R ³ are hydrogen atoms,
Hydroxyl group, aryl group or linear alkyl group having 1 to 10 carbon atoms
And R ² and R ³ are the same as each other.
Also, they may be different, and m represents 1 to 1,000.
You

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction content]

[0014]

[Chemical 1]

[Procedure amendment 4]

[Document name to be amended] Statement

[Name of item to be corrected] 0015

[Correction method] Change

[Correction content]

In the formula, R ¹ represents a hydroxyl group or a linear alkyl group having 1 to 10 carbon atoms, and R ² and R ³
Is a hydrogen atom, a hydroxyl group, an aryl group or 1 to 10 carbon atoms
And R ² and R ³ may be the same or different from each other, and m is 1 to 1,0.
Represents 00.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction content]

The invention according to claim 3 comprises an aqueous resin, a silicon compound represented by the following general formula, and a hexavalent chromium salt in an amount such that the ratio of chromium to the aqueous resin is 10 to 1,500 ppm. A surface-treated zinc-aluminum alloy-plated steel sheet, characterized in that the surface treatment agent is applied to the surface and dried.

[Chemical 1] However, in the formula, R ¹ is a hydroxyl group or has 1 to 10 carbon atoms.
Represents a straight chain alkyl group, R ² and R ³ are hydrogen atoms,
Hydroxyl group, aryl group or linear alkyl group having 1 to 10 carbon atoms
And R ² and R ³ are the same as each other.
Also, they may be different, and m represents 1 to 1,000.
You

[Procedure correction 6]

[Document name to be amended] Statement

[Name of item to be corrected] 0025

[Correction method] Change

[Correction content]

[0025]

[Chemical 1]

[Procedure Amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0026

[Correction method] Change

[Correction content]

In the formula, R ¹ represents a hydroxyl group or a linear alkyl group having 1 to 10 carbon atoms, and R ² and R ³
Is a hydrogen atom, a hydroxyl group, an aryl group or 1 to 10 carbon atoms
And R ² and R ³ may be the same or different from each other, and m is 1 to 1,0.
Represents 00.

[Procedure Amendment 8]

[Document name to be amended] Statement

[Name of item to be corrected] 0029

[Correction method] Change

[Correction content]

However, R ⁴ is a hydroxyl group and has 1 to 10 carbon atoms.
R ⁵ and R ⁶ each represent a hydrogen atom, a hydroxyl group, a methyl group or a phenyl group, R ⁵ and R ⁶ may be the same or different, and p and q are Each represents 1 to 500.

[Procedure Amendment 9]

[Document name to be amended] Statement

[Correction target item name] 0046

[Correction method] Change

[Correction content]

<Material> GF: 5% Al-Zn alloy plated steel sheet GL: 55% Al-Zn alloy plated steel sheet <Type of silicone compound> A: Dimethyl silicone oil (average molecular weight: about 8, 000) B ... Dimethyl silicone oil (average molecular weight; about 5,000) C ... Diethyl silicone oil (average molecular weight; about 1,000) D ... Alkyl-modified silicone oil (average molecular weight;
Approximately 15,000) <Type of hexavalent chromium compound> a ... Ammonium chromate b ... Ammonium dichromate c ... Strontium chromate

[Procedure Amendment 10]

[Document name to be amended] Statement

[Correction target item name] 0056

[Correction method] Change

[Correction content]

<Chromium Elution Test> A test piece was cut into a 10 mm square, a surface area of 400 cm ² was immersed in 200 ml of pure water, heated to 60 ° C., and chromium was eluted for 2 hours. After that, the test piece was taken out, the solution was made acidic with hydrochloric acid, and one drop of a 1% diphenylcarbazide solution was dropped to examine the presence or absence of chromium. Hexavalent chromium is present when the solution develops a yellow color. It was judged according to the following criteria.

Front Page Continuation (72) Inventor Anhei Sakamoto 202-3 Kitanoyukiya, Togane-shi, Chiba Prefecture (72) Inventor Tetsuya Watanabe 2-2-26-206 Fujigaoka, Fujisawa-shi, Kanagawa Prefecture (72) Ichiro Fukushima Miura, Kanagawa Prefecture 1079-59 Shimomiyata, Hatsunecho, Iwate

Claims (3)

[Claims] 1. A chromium content of 10 to 1,500 relative to an aqueous resin, a silicon compound represented by the following general formula, and the aqueous resin.
A surface treatment method for a zinc-aluminum alloy plated steel sheet, which comprises applying a surface treatment agent containing a hexavalent chromium salt in an amount of ppm to the surface of the zinc-aluminum alloy plated steel sheet. [Chemical 1] However, in the formula, R ¹ represents a hydroxyl group or a linear alkyl group having 1 to 10 carbon atoms, R ² and R ³ represent a hydroxyl group, an aryl group or a linear alkyl group having 1 to 10 carbon atoms, and R ² And R ³ may be the same as or different from each other, and m represents 1 to 1,000. 2. The surface treatment agent according to claim 1. 3. A chromium content of 10 to 1,500 relative to the water-based resin, the silicon compound represented by the following general formula, and the water-based resin.
A surface-treated zinc-aluminum alloy-plated steel sheet, which is obtained by applying a surface treatment agent containing a hexavalent chromium salt in an amount of ppm to the surface and drying it.