JPH115061A - Surface treated steel sheet excellent in corrosion resistance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a surface treated steel sheet excellent in corrosion resistance in a pollution-free state without treating with chromate treating solution harmful to environment and human body by forming a coating film of a high molecular chelating agent having a chelate forming group on the surface of a galvanized steel sheet or aluminum base plated steel sheet. SOLUTION: The surface treated steel sheet excellent in corrosion resistance is obtained by forming the high molecular chelating agent coating film having the chelate forming group in a high molecular matrix on the surface of the galvanized steel sheet or the aluminum base plated steel sheet. In such a case, the high molecular chelating agent coating film having the chelate forming group in the high molecular matrix having number average molecular weight of 300 is preferably formed in 0.01-5 μm thickness. And the coating film is suitably formed from a composition of 100 pts.wt. high molecular chelating agent having the chelate forming group in the high molecular matrix and 1-100 pts.wt. one kind selected from polyphosphates, phosphates, molybudates and the like in total.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface-treated steel sheet most suitable for use in automobiles, home appliances, and building materials. Environmentally-friendly surface treatment that does not contain any heavy metals such as chromium, lead, cadmium, and mercury that are harmful to the environment and the human body during manufacturing and in products in order to adapt to environmental issues such as volatilization and elution of harmful substances from products. It relates to a steel plate.

[0002]

2. Description of the Related Art Steel sheets for home appliances, building materials, and automobiles have been used to improve the corrosion resistance (white rust resistance, red rust resistance) on the surface of a zinc-based or aluminum-based steel sheet. A steel sheet which has been subjected to chromate treatment with a treatment liquid containing chromic acid, bichromic acid or salts thereof as a main component is widely used. This chromate treatment is an economical treatment method that has excellent corrosion resistance and can be performed relatively easily.

[0003] However, the chromate treatment uses hexavalent chromium, which is a pollutant-controlling substance. In the treatment process, the chromate salt has an adverse effect on the human body, and it is difficult to dispose of chromium sludge after wastewater treatment. In addition, there are various problems that the hexavalent chromium may be eluted from the product after the chromate treatment. Therefore, the use control standards for chromic acids have become stricter, and at the same time, problems such as management of a chromate treatment plant, wastewater treatment, and secondary contamination by chromate-treated products have been advanced. At present, each factory is taking measures to prevent pollution by preventing the discharge of chromium ions to the outside by closing the drainage system. In addition, rust-preventive oil for chromate-treated steel sheets,
In the press oil degreasing step, when an alkaline degreasing solution is used, particularly chromium is considerably eluted, and a dechroming treatment in the degreasing solution is required.

[0004] In view of the above, a number of pollution-free treatment techniques which do not rely on chromate treatment to prevent the generation of white rust on galvanized steel sheets have been proposed. For example, there is a method in which a thin film is formed by a method such as immersion, coating, or electrolytic treatment using an inorganic compound, an organic compound, an organic polymer material, or a solution in which these are combined.

Specifically, (1) a method using an oxide of a metal such as molybdenum and tungsten (for example, JP-A-57-5875); (2) a method using tannic acid (for example, 51-
(3) Pollution-free chromate treatment method containing trivalent chromium and containing no hexavalent chromium (see, for example, JP-A-61-587).
Publication).

[0006]

However, in the above method (1), the stable region against corrosion of metal oxides such as molybdenum and tungsten is narrower than that of chromium, and it is difficult to obtain the same corrosion resistance as chromate. Met.

In the method (2), a nonuniform colored film having uneven appearance is obtained.

Further, the method (3) does not basically meet the need for chromium-free because soluble chromium is used.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a surface-treated steel sheet which is safe during use and has excellent corrosion resistance.

[0010]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies in order to solve the above-mentioned problems, and as a result, have found that a polymer chelate having a chelate-forming group on the surface of a galvanized steel sheet or an aluminum-plated steel sheet. By forming a coating of the agent, we succeeded in obtaining a pollution-free and highly corrosion-resistant surface-treated steel sheet without using a chromate treatment solution that is harmful to the environment and the human body. That is, the surface-treated steel sheet of the present invention has the following configuration.

1. A surface treated steel sheet having excellent corrosion resistance, characterized in that a polymer chelating agent film having a chelating group in a polymer matrix is formed on a surface of a zinc-based plated steel sheet or an aluminum-based plated steel sheet.

2. A polymer chelating agent film having a chelating group in a polymer matrix having a number average molecular weight of 300 or more and having a chelating group is formed on a surface of a zinc-based plated steel sheet or an aluminum-based plated steel sheet in a thickness of 0.01 to 5 μm after drying. Surface treated steel sheet with excellent corrosion resistance.

3. 3. The surface-treated steel sheet having excellent corrosion resistance according to the above 1 or 2, wherein a film containing the following components is formed on the surface of the zinc-based plated steel sheet or the aluminum-based plated steel sheet.

(1) 100 parts by weight of a polymer chelating agent having a chelating group in a polymer matrix, (2)
Silica, polyphosphate, phosphate, molybdate,
A total of 1 to 100 parts by weight of at least one selected from phytic acid, phytate, phosphonic acid, and phosphonate.

4. 3. The surface-treated steel sheet having excellent corrosion resistance as described in 1 or 2 above, wherein a film containing the following components is formed on the surface of the zinc-based steel sheet or the aluminum-based steel sheet.

(1) 100 parts by weight of a polymer chelating agent having a chelating group in a polymer matrix, (2)
At least one solid lubricant selected from hydrocarbon compounds such as polyolefin wax, fluororesin compounds, fatty acid amide compounds, molybdenum disulfide, metallic soap, graphite fluoride, boron nitride and polyalkylene glycol 1 to 80 parts by weight in total.

5. 3. The surface-treated steel sheet having excellent corrosion resistance according to the above 1 or 2, wherein a film containing the following components is formed on the surface of the zinc-based plated steel sheet or the aluminum-based plated steel sheet.

(1) 100 parts by weight of a polymer chelating agent having a chelating group in a polymer matrix, (2)
Silica, polyphosphate, phosphate, molybdate,
(3) a total of 1 to 100 parts by weight of at least one selected from phytate, phosphonic acid and phosphonate;
At least one solid lubricant selected from hydrocarbon compounds such as polyolefin wax, fluororesin compounds, fatty acid amide compounds, molybdenum disulfide, metallic soap, graphite fluoride, boron nitride and polyalkylene glycol 1 to 80 parts by weight in total.

6. The chelating group imparted to the polymer matrix includes an amino acid group, a carboxyl group, a thiothiocarbamate, a polyamino group, a thiol group, a xanthate group, a thioureido group, a dithioic acid group, a β-diketone group, a hydroxamic oxime group, and Wherein the at least one selected from the salts of
The surface-treated steel sheet having excellent corrosion resistance according to 3, 4, or 5.

[7] FIG. The polymer matrix having a chelating group is polyethylene, polyvinyl alcohol, polyethylene glycol, polyethyleneimine, polyamino compound, polyvinyl chloride, polyacrylic acid, epoxy resin, phenol resin, styrene-divinylbenzene resin, acrylic resin, starch. 1, 2, 3, 4, 5 characterized in that it is at least one selected from the group consisting of:
Or a surface-treated steel sheet excellent in corrosion resistance according to 6.

Conventionally, a method for preventing corrosion of a metal surface by a chemical adsorption method using a corrosion inhibitor (inhibitor) has been known for a long time. Cooling water systems, boiler systems, water supply / hot water supply systems are mainly used as corrosion prevention methods for iron. For example, a method of adding an amine-based or phosphate-based adsorbent to water in an environment where water and metal are in constant contact with each other has been put to practical use.

The purpose of the present invention is to prevent corrosion of steel pipes for building materials, home appliances, automobiles and the like, as well as the purpose and application of the present invention, in addition to the corrosion prevention of plumbing systems around water. However, there has been almost no practical application of a coating mainly composed of a compound having a chelate-forming group for the purpose of these rust-proof steel sheets. The reasons are as follows: (1) the adsorption ability differs depending on the type of metal, and it is difficult to obtain a stable and dense adsorption film from a zinc-based plated steel sheet and an aluminum-based plated steel sheet; Due to the molecular weight, it is difficult to form a continuous film such as a polymer resin for coatings, and a sufficient anticorrosion function cannot be obtained because of such reasons.

As a result of intensive studies conducted by the present inventors to overcome the above-mentioned problems, they have found that a polymer chelating agent having a chelating group added to a polymer matrix has an excellent anticorrosive effect. is there. The features of the present invention are:
Instead of applying a low molecular weight chelating agent such as EDTA known in the art for rust prevention, a polymer chelating agent having a chelating group added to an organic polymer matrix is applied to a zinc-based plated steel sheet or aluminum. In that it is applied to system-plated steel sheets. It is a further feature of the present invention that the chelating group is desirably selected from a particular class. Further, it is desirable to select a specific type of organic polymer matrix.

Although the anticorrosion mechanism is not always clear,
(1) An organic film such as a coating resin can be formed by using a polymer chelating agent mainly composed of an organic polymer instead of a conventional low molecular weight chelating agent. (2) A specific chelating group Forms a stable and strong adsorption / reaction film with the surface of galvanized steel sheet or aluminum-coated steel sheet. (3) The chelation-forming group traps metal ions eluted during film formation to form a complex structure film. (4) By employing a polymer chelating agent having a polymer as a matrix instead of the conventional low molecular weight chelating agent, the chelating group traps metal ions eluted during film formation to form a complex. When a structural film is formed, a film having a three-dimensional polymer complex structure is formed, and a dense and stable three-dimensional ionic cross-linked structure film can be formed.
(5) When the steel sheet having the formed film is exposed to a corrosive environment, the metal ion eluted by dissolving the anode is supplemented by the chelate-forming group, and the electrically neutralized polymer complex structure similar to the above 4 It is considered that the generation of the sulfide suppresses the progress of corrosion.

The film containing a polymer chelating agent formed on the surface of a galvanized steel sheet or an aluminum-plated steel sheet has not only the effect that the polymer matrix forms a film in the same manner as the organic resin but also suppresses corrosion. The chelating group forms a dense protective film layer by adsorption or reaction on the surface of the plating film, and the chelating group traps zinc ions eluted during film formation to form a complex structure, forming a dense barrier layer. Can exhibit a rust prevention effect. Even when placed in a corrosive environment,
The free chelate-forming groups in the film trap zinc ions generated by the corrosion, and form a stable metal complex structure, thereby exhibiting the effect of suppressing the promotion of corrosion. Due to these multiple anti-corrosion effects, excellent corrosion resistance can be provided for the first time without using chromium.
Further, if necessary, a rust preventive additive and a solid lubricant are added so that more excellent corrosion resistance and lubricity can be imparted.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention and the reasons for limiting the same will be described below.

[0027] As the base zinc-coated steel sheet,
Galvanized steel sheet, Zn-Ni plated steel sheet, Zn-Fe plated steel sheet (electroplating, galvannealed), Zn-
Cr plated steel sheet, Zn-Mn plated steel sheet, Zn-Co plated steel sheet, Zn-Co-Cr alloy plated steel sheet, Zn-C
r-Ni plated steel sheet, Zn-Cr-Fe plated steel sheet, Z
n-Al plated steel sheet (for example, Zn-5% Al alloy plated steel sheet, Zn-55% Al alloy plated steel sheet), and further, zinc-based composite plated steel sheet (for example, Zn-SiO ₂ dispersion plating) can be used. Further, among the above platings, a multi-layer plated steel sheet obtained by plating two or more layers of the same or different types can be used. Aluminum-plated steel sheet, aluminum-plated steel sheet, Al-S
An i-plated steel sheet can be used. Further, between the above plating and the steel plate, a thin plating such as Ni may be applied in advance. As a plating method, any practicable method among an electrolysis method (electrolysis in an aqueous solution, electrolysis in a non-aqueous solvent), a melting method, and a gas phase method can be adopted.

Before applying the polymer chelating agent, the surface of the plated steel sheet may be subjected to pretreatment such as alkali degreasing treatment, if necessary, and surface conditioning treatment to improve adhesion and corrosion resistance.

Next, a polymer chelating agent having a specific chelate-forming group formed on the surface of the galvanized steel sheet or the aluminum alloy sheet will be described.

The chelate-forming group has a rust-preventing effect by chemically adsorbing on the plating metal surface, and further reacts with metal ions eluted from the plating at the time of film formation to form an insoluble dense chelate complex on the plating surface. It has.

The chelating groups provided to the organic polymer matrix include amino acid groups, carboxyl groups, thiocarbamic acid groups, polyamino groups, thiol groups, xanthate groups, thioureido groups, dithioic acid groups, β-diketone groups,
Hydroxam oxime groups and the like are used. The above chelating group may be in the form of a salt such as a Na salt, a K salt, an ammonium salt, and a Li salt. Examples of the amino acid group include a glycine group, a β-alanine group, and an iminodiacetic acid group.
Preferred chelating groups are dithiocarbamic acid groups, thiol groups and their Na, K, ammonium salts,
It is a salt such as a Li salt.

Examples of the organic polymer matrix into which the chelating group is introduced include polyethylene, polyvinyl alcohol, polyethylene glycol, polyethylene imine,
Polyamino compounds, polyvinyl chloride, polyacrylic acid,
Epoxy resins, phenolic resins, styrene-divinylbenzene resins, starch and the like are preferred. Preferred organic polymer matrices are polyamino compounds, polyethylene,
Polyethylene imine, polyvinyl chloride, polyacrylic acid, epoxy resin and the like.

The molecular weight of the organic polymer matrix may be arbitrary, but is 300 or more, preferably 1,000 or more, more preferably 10,000 or more, and particularly preferably 50,000 or more. When the molecular weight is 1,000 or less, the effect of improving corrosion resistance is small. On the other hand, if the molecular weight is too large, problems such as gelation of the coating composition may occur.
It is below 10,000.

As an example of the above-described polymer chelating agent, a heavy metal collecting agent industrialized for collecting heavy metals in wastewater treatment and heavy metals in fly ash can be applied. For example, Miyoshi Oil & Fats Co., Ltd. Epofloc L-1, Epofloc L-2, Kurita Kogyo Co., Ltd. Welklin K-100, Welklin K-200, etc. can be applied. Of course, synthetic products other than the above may be used.

For the purpose of further suppressing corrosion, silica, polyphosphate, phosphate, molybdate, phytate,
One or more of phosphonic acids and phosphonates can be blended.

The silica may be either colloidal silica or fumed silica. As colloidal silica, for example, Snowtex O, N, 20, 30, 40,
C and S (all manufactured by Nissan Chemical Industries, Ltd.) can be used.
As fumed silica, AEROSIL®
971, R812, R811, R974, R202, R
805, 130, 200, 300, 300 CF (or more,
Nippon Aerosil). These silicas contribute to the generation of dense and stable zinc corrosion products in a corrosive environment, and it is thought that the corrosion products can be formed densely on the plating surface, thereby suppressing the promotion of corrosion. Have been.

The amount of silica is 1 to 100 parts by weight (weight of silica solids) based on 100 parts by weight of the polymer chelating agent. If the amount is less than 1 part by weight, the effect of improving corrosion resistance after alkali degreasing is small. On the other hand, if it exceeds 100 parts by weight, paintability and workability are undesirably reduced.
Preferably, 5 to 80 parts by weight is appropriate.

Known corrosion inhibitors other than silica include known polyphosphates (for example, aluminum polyphosphate: Teika KW)
HITE80, 84, 105, G105, 90 (or more,
Teika Co., Ltd.)), phosphates (eg, zinc phosphate, aluminum dihydrogen phosphate, zinc phosphite, etc.), molybdate, phosphomolybdate (aluminum phosphomolybdate), phytic acid, phytate , A phosphonic acid or a phosphonate may be added.

The amount of the corrosion inhibitor other than silica (solid content of silica) is 1 to 100 parts by weight, preferably 5 to 8 parts by weight, based on 100 parts by weight of the polymer chelating agent.
0 parts by weight is appropriate, and when silica and a corrosion inhibitor other than the above-mentioned silica are used in combination, the above-mentioned compounding amount is the total amount obtained by further adding silica.

Further, for the purpose of improving the workability of the film, a solid lubricant can be blended if necessary.
Examples of the solid lubricant applicable to the present invention include the following.

(1) Hydrocarbon compounds such as polyolefin wax: for example, polyethylene wax, synthetic paraffin, natural paraffin, micro wax, chlorinated hydrocarbon and the like. (2) Fluororesin compound: For example, polyfluoroethylene resin (polytetrafluoroethylene resin, etc.), polyvinyl fluoride resin, polyvinylidene fluoride resin, etc. (3) Fatty acid amide compound: For example, stearamide, palmitic acid Amide, methylene bis-stearamide, ethylene bis-stearamide, oleic amide,
Esylamide, alkylenebisfatty acid amide and the like. (4) Metal soaps: for example, calcium stearate, lead stearate, calcium laurate, calcium palmitate and the like. (5) Metal sulfides: molybdenum disulfide and tungsten disulfide. (6) Others: For example, graphite, fluorinated graphite, boron nitride, polyalkylene glycol, alkali metal sulfate and the like.

Among the above solid lubricants, polyethylene wax and fluororesin-based compounds (particularly polytetrafluoroethylene resin fine particles) are preferred. Examples of polyethylene wax include Hoechst Cellidust 9615A, 371
5, 3620, 3910, sun wax 13 manufactured by Sanyo Kasei
1-P, 161-P, Chemipearl W manufactured by Mitsui Petrochemical Co., Ltd.
-100, W-200, W-500, W-800, W-
950 or the like can be used.

As the fluororesin, tetrafluoroethylene fine particles are preferable, and Lubron L-
2, L-5, MP1100, 120 manufactured by DuPont Mitsui
0, Fluon Dispersion AD1, AD2, Fluon L140, manufactured by Asahi ICI Fluoropolymers Co., Ltd.
J, L150J, L155J, etc. can be used. An excellent lubrication effect can be exhibited by using a combination of polyolefin wax and tetrafluoroethylene.

It is appropriate that the amount of these lubricants is 1 to 80 parts by weight based on 100 parts by weight of the polymer chelating agent in total. If the amount is less than 1 part by weight, the lubricating effect is poor, and if it is more than 80 parts by weight, the paintability deteriorates. Preferably 3
４０40 parts by weight.

Further, as other additives, coloring dyes (eg, organic solvent-soluble azo dyes, water-soluble azo metal dyes, etc.) and organic coloring pigments (eg, condensed polycyclic organic pigments, phthalocyanine organic pigments, etc.) ), Inorganic pigments (titanium oxide), chelating agents (thiols, etc.), conductive pigments (eg, metal powders such as zinc, aluminum, nickel, iron phosphide, antimony-doped tin oxide, etc.), coupling agents (eg, Silane coupling agents, titanium coupling agents, etc.), melamine / cyanuric acid adducts, and the like.

The polymer chelating agent is applied in a solution state. When the polymer chelating agent is water-soluble, the solvent may be an aqueous solution, and the concentration may be about 1 to 40% (% by weight).

The above-mentioned polymer chelating agent film is applied to the surface of a galvanized steel sheet or an aluminum-plated steel sheet without performing a chromate treatment. The film thickness after drying may be any thickness, but is preferably 0.0
1 to 5 μm. If the thickness is less than 0.01 μm, the corrosion resistance is insufficient.
If it exceeds, weldability will decrease. More preferably 0.05
To 3 μm, and more preferably 0.1 to 2 μm.

As a method of forming the coating composition containing the above-mentioned polymer chelating agent on the surface of a zinc-based steel sheet or an aluminum-based steel sheet, any of coating, dipping and spraying may be used. As a coating treatment method, any method such as a roll coater (three-roll method, two-roll method, etc.), a squeeze coater, a die coater and the like may be used. Also,
After the application treatment with a squeeze coater or the like, or the dipping treatment or the spray treatment, the application 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 these coatings, heating and drying are performed without washing with water. However, since the polymer chelate film of the present invention is bonded to the underlying zinc-based plated steel sheet or aluminum-based plated steel sheet by chemical adsorption or reaction, it is also possible to carry out a washing step after coating.

As the heating and drying method, a dryer,
A hot blast furnace, a high-frequency induction heating furnace, an infrared furnace, or the like can be used. The heat treatment is desirably performed at a temperature of the ultimate plate temperature of 50 to 300C, preferably 80 to 250C. If the heating temperature is lower than 50 ° C., a large amount of water in the film remains, and the corrosion resistance becomes insufficient. On the other hand, when the temperature exceeds 300 ° C., it is not only uneconomical, but also a defect occurs in the film and the corrosion resistance is lowered.

The present invention includes a steel sheet having the above-described coating on both sides or one side. Examples of the form of the steel sheet of the present invention include the following.

(1) One side: plating film-polymer chelating agent film, one surface: plating film (2) Direction: plating film-polymer chelating agent film, one surface: known phosphate treatment film, etc. (3) Both sides: plating film-polymer chelating agent film

[0053]

EXAMPLE As a surface-treated steel sheet for home appliances, building materials, and automobile parts, the surface of a zinc-based plated steel sheet or an aluminum-based plated steel sheet (Table 1) is subjected to alkali degreasing treatment, washed with water and dried, and then subjected to various types of matrices. Coating consisting of high molecular weight chelating agent consisting of various chelating groups (Table 2), silica (Table 3), rust preventive additives other than silica (Table 4), solid lubricant (Table 5) if necessary The composition (Table 6) was applied by a roll coater and dried by heating at various temperatures.

As the polymer chelating agent, for example, Table 2
As shown in Example 1, Miyoshi Oil & Fats Co., Ltd. Epofloc L-1 (molecular weight: 80,000 to 120,000, chelate forming groups: Na base dithiocarbamate and Na base thiol) were used. Further, for example, as shown in Table 14, a combination of various matrices and chelating groups was used.

The thickness of the film was adjusted by the solid content concentration of the coating composition (residual residue after heating) or the application conditions (roll rolling force, rotation speed, etc.). Tables 7 to 13 show the results of tests of the obtained surface-treated steel sheet, which were performed on corrosion resistance, paint adhesion, and workability. The manufacturing conditions and the quality performance evaluation method of this example are as follows.

(1) Plated Steel Sheet A cold-rolled steel sheet having a thickness of 0.8 mm and a surface thickness (Ra) of 1.0 mm was subjected to various types of zinc plating or aluminum plating to be used as a base plate for treatment (see Table 1).

(2) A coating composition containing a polymer chelating agent as a main component The following polymer chelating agent aqueous solution is used as a main component, and if necessary, a rust preventive additive and a solid lubricant are added to a coating nutrient acidizer ( Using a sand grinder), the mixture was dispersed for a required time to obtain a coating composition.

(2-1) Polymer Chelating Agent An aqueous polymer chelating agent solution comprising an organic polymer matrix and a chelating group shown in Table 2 was used. In addition, as a comparative example, a tannic acid aqueous solution conventionally known as a rust inhibitor and EDT which is a low molecular weight chelating agent are used.
A (ethylenediaminetetraacetic acid) aqueous solution was used. (2-2) Rust prevention additives Silica shown in Table 3 and polyphosphate, phosphate, molybdate, phytic acid, phytate, phosphonic acid and phosphonate shown in Table 4 were used. (2-3) Solid lubricant A solid lubricant shown in Table 5 was used.

[Evaluation Method of Quality Performance] (1) Coating Appearance Each sample was visually evaluated for uniformity of coating appearance (with or without unevenness). The evaluation criteria are as follows. ：: uniform appearance without any unevenness △: appearance with some unevenness ×: appearance with unevenness

(2) White rust resistance For each sample, salt spray test (JIS-Z-23)
71) and evaluated by the area ratio of white rust after a predetermined time.
The film containing no silica was evaluated by white rust resistance after 48 hours, and the film containing a rust-preventive additive (silica, a rust-preventive additive other than silica) was treated in 48 hours by the rust-preventive effect of silica. More severe 72
Time later evaluated. The determination method is 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) Coating Adhesion For each sample, a melamine-based baked coating (thickness: 30 μm) was applied, immersed in boiling water for 2 hours, and immediately cut in a grid (10 × 10, 1 mm interval). , And peeled off with a cellophane tape. The criteria are as follows. ：: No peeling ○: Peeling area rate less than 5% △: Peeling area rate 5% or more, less than 20% ×: Peeling area rate 20% or more

(4) Workability Deep drawing was performed with a blank diameter of φ120 mm and a die diameter of φ50 mm (without oiling), and evaluated by the molding height until cracks occurred. The evaluation criteria are as follows. ◎: Draw-out ○: Molding height 30 mm or more △: Molding height 20 mm or more, less than 30 mm ×: Molding height less than 20 mm

[0063]

[Table 1]

[0064]

[Table 2]

[0065]

[Table 3]

[0066]

[Table 4]

[0067]

[Table 5]

[0068]

[Table 6]

[0069]

[Table 7]

[0070]

[Table 8]

[0071]

[Table 9]

[0072]

[Table 10]

[0073]

[Table 11]

[0074]

[Table 12]

[0075]

[Table 13]

[0076]

[Table 14]

[0077]

[Table 15]

[0078]

According to the present invention, a surface-treated steel sheet having excellent corrosion resistance can be provided without using chromium.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Masaru Sagiyama 1-2-1 Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd.

Claims (7)

[Claims] An excellent corrosion resistance characterized in that a polymer chelating agent film having a chelating group in a polymer matrix is formed on the surface of a zinc-based plated steel sheet or an aluminum-based plated steel sheet. Surface treated steel sheet 2. The polymer chelating agent has a number average molecular weight of 30.
0 or more having a chelate forming group in a polymer matrix, and the film has a thickness of 0.01 to
The surface-treated steel sheet having excellent corrosion resistance according to claim 1, wherein the thickness is 5 μm. 3. A polymer chelating agent film containing 100 parts by weight of a polymer chelating agent, silica, polyphosphate, phosphate, molybdate, phytic acid, phytate, phosphonic acid, phosphonate. At least one selected from
The surface-treated steel sheet having excellent corrosion resistance according to claim 1 or 2, wherein the total amount of the seed is 1 to 100 parts by weight. 4. A polymer chelating agent film wherein a hydrocarbon compound such as polyolefin wax, a fluororesin compound, a fatty acid amide compound, molybdenum disulfide, metal soap, fluorinated compound is used per 100 parts by weight of the polymer chelating agent. A total of at least one solid lubricant selected from graphite, boron nitride and polyalkylene glycol is 1 to 8
4. The surface-treated steel sheet having excellent corrosion resistance according to claim 1, wherein the steel sheet contains 0 parts by weight. 5. The polymer chelating agent film further comprises a hydrocarbon-based compound such as polyolefin wax, a fluororesin-based compound, a fatty acid amide-based compound, molybdenum disulfide, a metallic soap, a fluorine-containing compound, based on 100 parts by weight of the polymer chelating agent. A total of at least one solid lubricant selected from graphite graphite, boron nitride and polyalkylene glycol;
The surface-treated steel sheet having excellent corrosion resistance according to claim 3 or 4, wherein the surface-treated steel sheet comprises -80 parts by weight. 6. The chelating group includes an amino acid group, a carboxyl group, a thiothiocarbamic acid group, a polyamino group, a thiol group, a xanthate group, a thioureido group, a dithioic acid group,
The surface-treated steel sheet having excellent corrosion resistance according to claim 1, which is at least one selected from a β-diketone group, a hydroxam oxime group, and a salt thereof. 7. A polymer matrix comprising polyethylene,
Polyvinyl alcohol, polyethylene glycol, polyethylene imine, polyamino compound, polyvinyl chloride,
7. The method according to claim 1, wherein the resin is at least one selected from polyacrylic acid, epoxy resin, phenol resin, styrene-divinylbenzene resin, acrylic resin, and starch. Treated steel sheet with excellent corrosion resistance