JP2000226690A - Production of surface treated metallic sheet for coating substrate and surface treated metallic sheet for coating substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a metallic sheet excellent in corrosion resistance and forming workability by subjecting a metallic sheet to cathodic treatment or anodic treatment in an aq. soln. of specified pH composed of one or more kinds among binding agents composed of inorganic compds. and one or more kinds among metallic ion feeding substances and forming a film composed of sollike hydrated oxide or sollike hydrated oxide and metal on the metallic plate. SOLUTION: One or more kinds among inorganic compds. such as sodium silicate and one or more kinds among metallic ion feeding substances such as aluminum are dissolved into water of 5 to 300 g/l conc., its pH is adjusted to 2 to 11 to form into a treating soln. A metallic sheet such as a cold rolled steel sheet as-rolled or a plated steel sheet plated with zinc or the like is subjected to electrolyzing treatment at 0.1 to 50 A/dm2 current density, at 20 to 50 deg.C for 0.5 to 20 sec to form a film of 0.005 to 1 μm thickness composed of sollike hydrated oxide or sollike hydrated oxide and metal. It is water-washed or is not water-washed and is dried to obtain a surface treated metallic sheet for a coating substrate excellent in adhesion for a coating film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a surface-treated metal sheet for a coating base, and a surface-treated metal sheet for a coating base prepared by using the method. More specifically,
By using a method for producing a surface-treated metal sheet for a coating base, and a method for improving the corrosion resistance, molding workability, and coating film adhesion of a coated metal sheet obtained by applying a coating to a metal sheet, and The present invention relates to a prepared surface-treated metal plate for a coating base.

[0002]

2. Description of the Related Art Metal sheets such as cold-rolled steel sheets and aluminum alloy sheets are inexpensive and have excellent mechanical properties.
When used in the as-rolled state, they are easily rusted and cause many practical problems in corrosion resistance and coating film adhesion when coated. Therefore, the metal plate after rolling is subjected to a surface treatment such as plating or anodizing treatment. Further, in order to obtain sufficient corrosion resistance, a coating is often further applied thereon. In order to improve the adhesion between the coating and the metal plate by this coating, surface treatment such as phosphate treatment or chromate treatment is applied directly on the metal plate or on the plating applied to the metal plate. Is done.

[0003] However, such conventional surface treatments have a number of disadvantages inherent in them, and improvements are required. For example, in the conventional chromate treatment of galvanized steel sheet, zinc reacts with a chemical conversion treatment agent in a treatment tank to generate sludge, and it is necessary to improve work environment conservation and economy. As a remedy, a coating type chromate treatment that does not require a treatment tank has been developed, but it is not satisfactory in characteristics such as environmental protection and moldability, and further improvement is required.

[0004]

SUMMARY OF THE INVENTION In the present invention, in order to solve the above-mentioned drawbacks of the prior art, not only is the work environment preserving excellent, but also the corrosion resistance and the formability of the coated metal sheet are improved.
It is another object of the present invention to provide a method for producing a surface-treated metal plate for a coating base having excellent coating film adhesion, and a surface-treated metal plate for a coating base prepared by using the method.

[0005]

According to the present invention, there is provided a method for producing a surface-treated metal sheet for use as a base material for coating, comprising a step of preparing a surface-treated metal sheet having a pH of 2 or more comprising at least one binder composed of an inorganic compound and at least one metal ion donor. In the aqueous solution of No. 11, a metal plate was subjected to a cathodic treatment or an anodizing treatment to form a sol-like hydrated oxide on the metal plate, or a film composed of the sol-like hydrated oxide and the metal on the metal plate. After that, it is characterized in that it is dried as it is without or after washing with water. Alternatively, pH 2 to 11 comprising at least one kind of a binder comprising an inorganic compound
After subjecting a metal plate to a cathodic treatment or an anodizing treatment in an aqueous solution of the above, after forming a sol-like hydrated oxide on the metal plate or a film composed of the sol-like hydrated oxide and the metal on the metal plate Then, it is dried as it is without or after washing with water. The binder comprising the inorganic compound,
It is preferably any of alkali metal salts, acidic metal salts, colloidal metal oxides, metal alkoxides, metal acylates, and organic / inorganic hybrid resins. The metal ion supply material is aluminum, chromium, molybdenum,
It is preferable that the material is a supply material of ions derived from any of tungsten, titanium, zirconium, vanadium, cerium, zinc, tin, nickel, cobalt, and copper.
In addition, the surface-treated metal sheet for a coating base of the present invention can be obtained by using any one of the above-mentioned methods for producing a surface-treated metal sheet, and forming a sol-like hydrated oxidized film having a thickness of 0.005 to 1 μm on the metal sheet. object,
Alternatively, it is a surface-treated metal plate for a coating base formed by forming a film composed of a sol-like hydrated oxide and a metal.

[0006]

DETAILED DESCRIPTION OF THE INVENTION In the present invention, a binder made of an inorganic compound or a treatment solution to which a metal ion is further added is used to directly or on a plated metal plate. It has been found that the object of the present invention can be achieved by forming a sol-like hydrated oxide or a film composed of a sol-like hydrated oxide and a metal.

Hereinafter, the present invention will be described in detail. First, as a metal sheet applicable to the present invention, in addition to a cold-rolled steel sheet in an as-rolled state, a coated steel sheet such as a hot-dip coated steel sheet, an electroplated steel sheet, a composite plated steel sheet, and a vapor-deposited steel sheet is included. Metals to be plated include zinc, tin, aluminum, nickel, copper, chromium, and alloys thereof. In addition to the cold-rolled steel sheet and the plated steel sheet, an aluminum sheet, an aluminum alloy sheet, a copper sheet, a copper alloy sheet, a stainless steel sheet and the like can be mentioned.

Next, the processing liquid used for forming the pretreatment film will be described. As the binder composed of an inorganic compound contained in the treatment liquid, those generally used as binders for inorganic paints can be applied as they are.
Examples include silicates such as sodium silicate, potassium silicate, and lithium silicate; alkali metal salts such as zirconium salts including alkali zirconium; acidic metal salts such as aluminum phosphate; aluminum, tin, nickel, and cobalt. Metal oxides such as colloidal silica and colloidal alumina, which are oxides of metals that form hydrated oxides such as zinc, vanadium and zirconium; metal alkoxides which are alkoxy metals such as tetrabutyl zirconate and tetrabutyl titanate Silicon acylate including silicon tetraacetate,
Metal acylates such as aluminum stearate, metal acylates such as alkyl metals such as triethylaluminum, organopolysiloxanes such as silicone resins, organoalkoxysilanes such as methyltrimethoxysilane, and tetrabutylzirconate. Organic / inorganic hybrid resins such as zirconia silicon including silicon resin, and acrylic silicate including amine silicate and acrylic resin are exemplified.

[0009] Further, in the treatment liquid, aluminum, chromium, molybdenum, tungsten, titanium, zirconium, vanadium, cerium,
Zinc, tin, nickel, cobalt, copper and the like may be contained. Among them, zinc, tin, nickel, cobalt, copper and the like are present in the treatment liquid as these ions, but depending on the pH of the aqueous solution, they may be present as zincate ions or stannate ions. Metals other than these metals are present in the treatment liquid as chromate ions, molybdate ions, tungstate ions, titanate ions, vanadate ions, or compounds with these ions. The ion supply substance used in the present invention can be applied as long as it can be dissolved in the processing liquid, and is not limited to the above metals. By treating in a treatment solution containing a binder composed of the above-mentioned inorganic compound, or a treatment solution to which these ion supply substances are further added,
A film composed of sol or sol and metal is formed. The addition of metal ions densifies the sol that forms the film, improves the adhesion with the organic / inorganic hybrid film that is formed on the sol, promotes the formation of a strong main treatment film, and improves corrosion resistance, moldability, Improves properties such as coating adhesion.

Next, a method of forming a film will be described.
5 to 300 g / l of one or more binders composed of the above-mentioned inorganic compounds and / or one or more above-mentioned ion donors
Dissolve in water at a concentration of to make a treatment solution. When the concentration is less than 5 g / l, the deposition efficiency of the film is remarkably reduced, and 300 g / l
When the value exceeds 1, the effect of improving characteristics is saturated, and the loss due to drag-out increases, resulting in loss of economy. The pH of the treatment liquid is preferably in the range of 2 to 11, and 3 to 1
More preferably, it is in the range of 0. When the pH is less than 2 or more than 11, the success rate of hydrated oxide formation decreases. The pH is adjusted by adding an acidic solution or an alkaline solution to the treatment solution.

[0011] The ionicity of the binder comprising the above-mentioned inorganic compound may be affected by the pH of the processing solution. For example,
In the treatment liquid having a pH of 4, the hydrated aluminum sol is positively charged, while the silica sol is negatively charged. When both are mixed, they are often positively charged. In these cases, it is preferable to use a cathodic electrolytic treatment for deposition of the film. As described above, in order to select an optimal method for depositing a film, it is necessary to check the ionicity of the binder made of an inorganic compound in advance.

The above-mentioned film can be obtained by immersing the metal plate in the processing solution and then drying and solidifying the metal plate. However, the metal plate is subjected to a cathode treatment or an anodic treatment in the processing solution. Can be obtained by performing the electrolytic treatment described above. The polarity of the electrolytic treatment is appropriately selected based on the ionicity of the binder made of the inorganic compound as described above. The current density is preferably in the range of 0.1 to 50 A / dm ² .
The temperature of the treatment liquid is preferably in the range of 20 to 50C. Although the processing time depends on the thickness of the film, a practical range of 0.5 to 10 seconds is practical. According to the Hull cell test, a sol is easily formed at a low temperature and a high current density of a processing solution, but a brittle sol tends to be formed. Further, since the current density and the processing time are related to the film thickness of the film, it is preferable to select a practical temperature range and current density of the processing solution in consideration of the film thickness of the film to be formed by a Hull cell test in advance. . The thickness of the treated film obtained as described above is
It is preferably 0.005 to 1 μm. 0.005μ
If it is less than m 2, the effect of improving the properties is not recognized, and if it exceeds 1 μm, the moldability will be significantly lower.

After the treatment film is formed on the metal plate as described above, it is dried as it is, or immediately after washing with water. Regarding the presence or absence of water washing after forming the film, when acids or alkalis are added to the treatment liquid for pH adjustment, these acids and alkalis remain in the film and decrease the corrosion resistance and coating film adhesion. Therefore, it is preferable to wash with water.

The surface-treated metal plate obtained by forming the coating of the present invention on the above-mentioned plated steel plate, aluminum alloy plate, stainless steel plate, or copper alloy plate is not only used as a surface-treated plate for a base material for coating, but is not coated. It can be applied to unpainted applications as it is.

[0015]

The present invention will be described in more detail with reference to the following examples. (Example) [Metal plate] As a substrate used for the surface-treated metal plate of the present invention, a metal plate shown in Table 1 having a thickness of 0.3 mm was subjected to buff polishing, followed by electrolytic alkali degreasing treatment and pickling treatment. Used metal plate. In Table 1, the cold-rolled steel sheet is SS,
Each hot-dip coated steel sheet (galvanized steel sheet, Zn-5% Al alloy coated steel sheet, aluminum-coated steel sheet)
n (H), Zn-5% Al (H), Al (H), electroplated steel sheet (galvanized steel sheet, Zn-2% Co-0.5
% Mo alloy-plated steel sheet, nickel-plated steel sheet, tin-plated steel sheet, copper-plated steel sheet, chromium-plated steel sheet), respectively, Zn (E), Zn-2% Co (E), Ni (E)
(E), Cr (E), vacuum-deposited galvanized steel sheet
(V), the aluminum alloy plate is made of AlS, and the copper plate is made of Cu
In S, a stainless steel plate is shown by SUS. These metal plates were buffed before the surface treatment of the present invention, and then subjected to electrolytic alkali degreasing and pickling to clean the surfaces.

A coating was formed on the metal plate whose surface was cleaned as described above using the treatment liquid shown in Table 1 under the conditions shown in Table 1.

[0017]

[Table 1]

[Evaluation of Properties] The corrosion resistance, coating film adhesion, and moldability of the surface-treated metal sheet obtained as described above were evaluated under the following conditions. As comparative materials, commercially available cold-rolled steel sheets subjected to a phosphoric acid treatment and a chromate treatment (comparative material 1), tin-plated steel sheets subjected to a coating-type chromate treatment (comparative material 2), and electric zinc A coated steel sheet subjected to a coating type chromate treatment (Comparative Material 3) was evaluated under the same conditions. Corrosion Resistance An organic solvent-based acrylic resin paint was applied to the surface-treated metal plate so as to have a thickness of 15 μm after baking and curing, and baked. After performing a salt spray test on the coated metal plate in accordance with JIS Z 2371 for 500 hours, the state of occurrence of blisters generated on the surface was visually observed and evaluated by the following rating. ：: No problem in practical use. ×: Blisters of a practically problematic level are observed on the surface.

Coating film adhesion An organic solvent-based acrylic resin was applied to the surface-treated metal plate so that the film thickness after baking and curing became 15 μm, and baked. The coated metal plate was drawn into a cylindrical cup shape at a draw ratio of 2.2, the coating on the side surface of the cup was forcibly peeled off with an adhesive tape, the degree of peeling of the coating was visually observed, and evaluated by the following rating. ：: No problem in practical use. ×: Peeling to a degree that is problematic in practical use is observed.

Formability The organic solvent-based acrylic resin was applied to the surface-treated metal plate so that the film thickness after baking and curing was 15 μm, and baked. The coated metal plate was processed with a Dupont impact tester (shape of impact applied portion: hemisphere having a radius of 1/2 inch, weight of impact applied portion: 500 g, drop height: 50 cm). The coating film was forcibly peeled off with an adhesive tape, and the degree of peeling of the coating film was visually observed and evaluated according to the following rating. ：: No problem in practical use. ×: Peeling to a degree that is problematic in practical use is observed. Table 2 shows the results of the above characteristic evaluation.

[0021]

[Table 2]

As shown in Table 2, the surface-treated metal sheet coated with the treated film of the present invention has excellent corrosion resistance, coating film adhesion, and moldability.

[0023]

The present invention provides a binder comprising an inorganic compound,
Alternatively, using a treatment solution comprising metal ions, a sol-like hydrated oxide or a sol-like hydrated oxide-metal film is formed directly on a metal plate or on a plated metal plate. A method for producing a surface-treated metal sheet for a coating base to be formed, and a surface-treated metal sheet for a coating base obtained by using the method. The production method of the present invention is excellent in work environment preservation, The surface-treated metal sheet for the base of the coating made of is excellent in corrosion resistance, molding workability, and coating film adhesion.

Claims (5)

[Claims] 1. A binder comprising at least one inorganic compound,
Further, the pH 2 comprising at least one kind of metal ion supplying substance
In the aqueous solutions of ~ 11, the metal plate is subjected to a cathodic treatment or an anodizing treatment to form a sol-like hydrated oxide on the metal plate, or a film composed of the sol-like hydrated oxide and the metal on the metal plate. A method for producing a surface-treated metal sheet for a base material for coating, comprising drying after washing, or after washing without or after washing with water. 2. A metal plate is subjected to a cathodic treatment or an anodizing treatment in an aqueous solution of at least one kind of a binder composed of an inorganic compound and having a pH of 2 to 11, and a sol-like hydrated oxide or a metal is formed on the metal plate. A method for producing a surface-treated metal sheet for a coating base, comprising forming a sol-like hydrated oxide and metal film on a sheet, and then drying the sheet after washing with or without washing with water. 3. The method according to claim 1, wherein the binder comprising the inorganic compound is any one of an alkali metal salt, an acidic metal salt, a colloid metal oxide, a metal alkoxide, a metal acylate, and an organic / inorganic hybrid resin. The method for producing the surface-treated metal sheet for a coating base described in the above. 4. The method according to claim 1, wherein the metal ion donor is a source of ions derived from any of aluminum, chromium, molybdenum, tungsten, titanium, zirconium, vanadium, cerium, zinc, tin, nickel, cobalt and copper. Item 4. The method for producing a surface-treated metal sheet for a coating base according to any one of Items 1 to 3. 5. The method for producing a surface-treated metal sheet according to claim 1, wherein 0.005 to 1 μm is formed on the metal sheet.
A surface-treated metal plate for a coating base formed by forming a sol-like hydrated oxide having a thickness of m or a film composed of a sol-like hydrated oxide and a metal.