JPH01149966A - Manufacture of colored stainless steel sheet excellent in resistance to wear, heat, and fingerprint - Google Patents

Abstract

PURPOSE:To manufacture a colored steel sheet excellent in wear resistance, heat resistance, and fingerprint resistance by subjecting a stainless steel sheet to immersion treatment in a mixed aqueous solution of chromic acid and sulfuric acid, applying an alcohol solution of alcoxide, etc., to the above sheet, and then heating the above. CONSTITUTION:A stainless steel sheet is subjected to immersion treatment in a mixed aqueous solution of chromic acid and sulfuric acid, by which a colored oxide film is formed on the steel sheet surface. Subsequently, an alcohol solution containing >=0.05% of at least one kind among the alcoxides of Si, Al, Ti, and Zr, acetylacetonate complexes, and the metallic salts of octylic acid is applied to the surface of the above colored oxide film. It is suitable that the coverage is regulated so that the thickness of the metal-oxide film obtained by heating is about 0.01mum, preferably about 0.01-0.6mum. By heating the above coated surface at 200-500 deg.C, the film of the above metal oxide can be formed with superior adhesive strength.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention provides Si,
The present invention relates to a method for manufacturing a colored stainless steel sheet with improved wear resistance, heat resistance, fingerprint resistance, etc. by forming an oxide film of Al, Ti, Zr, etc.

[Conventional technology and problems]

Colored stainless steel sheets have a better design than uncolored stainless steel sheets, and are therefore becoming more widely used as building materials. Various methods have been proposed and implemented for coloring stainless steel.

Among these methods, the method of coloring stainless steel by immersing it in a sulfuric acid-chromic acid mixture can change the hue (color tone) only by changing the treatment time. This is an excellent coloring method that does not cause fading compared to other methods. However, the colored oxide film made of chromium hydroxide formed by immersion in a mixed aqueous solution of chromic acid and sulfuric acid has a problem in wear resistance because it is porous.

Conventionally, in order to overcome this drawback, after forming the above-mentioned colored film, further electrolytic chromic acid treatment is performed to harden the film by electrodepositing metallic chromium on the surface of the colored film, or the above-mentioned method is used. A method is being used to improve wear resistance by applying a clear coat to the surface layer of the colored oxide film. However, the electrolytic chromic acid treatment method has disadvantages such as poor heat resistance and high concentration of chromic acid in the treatment liquid, which increases waste liquid treatment cost and causes a large pollution problem. The clear coating method has the problem that it not only reduces the vividness of the color of the colored film but also reduces its heat resistance and weather resistance. Therefore, there has been a demand for the development of a method for improving the abrasion resistance, etc. of colored oxide films instead of these.

[Knowledge for solving good luck]

The present inventor has discovered that Si on a colored film formed by immersing stainless steel in a chromic acid-sulfuric acid mixed aqueous solution,
If a metal oxide film is formed using an alkoxide of Al, Ti, Zr, etc., a film with excellent adhesion can be obtained, and as the colored film is protected by the oxide film, wear resistance is improved. It was discovered that a colored stainless steel sheet with excellent properties such as hardness and heat resistance can be produced, and that it does not cause any problems when disposing of waste liquid.

[Structure of the invention]

According to the present invention, a stainless steel plate is immersed in a mixed aqueous solution of chromic acid and sulfuric acid to form a colored film on the surface of the steel plate, and then Si and AI are applied to the surface of the film.

At least one of Ti, Zr alkoxide, acetylacetonate complex, or octylate metal salt is added to 0.
2 by applying an alcohol solution containing 0.05% by weight or more.
Provided is a method for producing a colored stainless steel sheet with excellent wear resistance, heat resistance, and fingerprint resistance, which is characterized by forming an oxide film of the metal by heating at 00°C to 5006°C.

The method of the present invention includes the steps of forming a colored film on the surface of a stainless steel plate, and adding Si, Al, and Ti on the colored film.

and forming a Zr metal oxide film.

In the step of forming the colored film, the stainless steel plate is immersed in a mixed aqueous solution of chromic acid and sulfuric acid, and a chromium-rich colored oxide film layer is formed on the surface of the stainless steel plate by the immersion treatment.3. Details are explained in Japanese Patent Application Laid-Open No. 11243/1983.

After forming the colored oxide film, an alcohol solution containing at least one of Si, Al, Ti, and Zr alkoxides, acetylacetonate complexes, or octylic acid metal salts is applied, and further A heat treatment is performed to form an oxide film of the metal. Alkoxides of Si, AΩ, Ti, Zn, etc. are used because their oxides have excellent heat resistance, wear resistance, etc.

SL, Al, Ti, Zr alkoxide or acetylacetonate complex or octylic acid metal salt, specifically, ethyl silicate, methyl silicate,
Monomethyltriethoxysilane, monomethyltrimethoxysilane, aluminum isopropoxide, titanium isopropoxide, zirconium isopropoxide, aluminum acetylacetonate, titanium acetylacetonate, zirconium octylate, aluminum octylate, and the like are used.

The alcohol solvent is not particularly limited as long as it can uniformly disperse the above compound. For example, methanol, ethanol, butanol, etc. can be used.

The content of octylic acid metal salt in the alkoxide and acetylacetonate armor body λ is required to be 0.05% by weight or more. The reason why the content is 0.05% by weight or more is 0.05% by weight or more.
This is because if the amount is less than 0.5% by weight, the metal oxide film formed by this etc. will become thin, making it impossible to obtain sufficient wear resistance, heat resistance, etc.

It is also possible to add an acid such as hydrochloric acid, nitric acid, or an organic acid as a catalyst to the solution in order to promote the hydrolysis of the metal alkoxide, acetylacetonate complex, or octylate metal salt.

The solution may be applied to the stainless steel plate by any method that can uniformly apply the solution, such as a dipping method, a spray method, a roll coating method, or a spin method.

The coating amount of the above solution is such that the thickness of the metal oxide film after heating is 0.01 μm or more, preferably 0.01 μm to 0.6 μm.
The thickness is adjusted to .mu.m, more preferably 0.2 to 0.3 .mu.m. If the film thickness is less than 0.01 μm, the wear resistance, heat resistance, and finger squeeze resistance will be poor, and if it is thicker than 0.6 μm,
The flexibility of the film decreases and cracks are more likely to occur.

The alkoxide, acetylacetonate tank body, and octylic acid metal salt are hydrolyzed in an alcohol solution to form a hydroxide, and by heat treatment, the hydroxide is dehydrated and condensed to form an oxide film. . Heating temperature is 200
~500°C.

The reason why the heating temperature is set to 200 to 500°C is that 200°C
If it is less than 500°C, the dehydration condensation of SL, Al, Ti, Zr alkoxides, acetylacetonate complexes, and their octylic acid metal salts will not proceed sufficiently, and the metal oxide film will become non-uniform. This is because if the temperature exceeds 100%, the alcohol will evaporate rapidly and pinholes will occur in the film.

〔Effect of the invention〕

According to the method of the present invention, gold fF, which has excellent wear resistance, heat resistance, and corrosion resistance, is added to the surface f of the colored film! Since an oxide film is formed, a colored stainless steel sheet with excellent properties can be obtained. Further, the metal oxide film does not leave fingerprint marks and has excellent finger squeeze resistance.

Furthermore, the metal oxide film has excellent adhesion. The reason for this is that the hydroxyl group of chromium hydroxide remaining in the colored oxide film and the 5i-OH, Al-OH, Ti-0H1Zr-OH present in the alcohol solution of the above alkoxide, etc.
This is because a dehydration condensation reaction progresses and a chemical bond is formed between the hydroxyl group and the like.

[Examples and comparative examples]

0.4mm thick stainless steel plate (SUS304.5US
430) in a mixed aqueous solution of chromic acid and sulfuric acid to color it blue, gold, and green, it was immersed in a solution with the composition shown in Table 1, and pulled up at a constant speed of 3 mm/sec.
The solution was uniformly applied to the surface of the stainless steel plate. After that, these rigid plates were placed in an electric oven at 300°C for 1 minute.
It was heated to form an oxide film. On the right side of Table 1, the obtained colored stainless steel sheets are shown below. On the other hand, after the stainless steel plate was treated in a mixed aqueous solution of chromic acid and sulfuric acid to form a colored film, there were samples with no protective film applied thereon (Nα13-16) and samples with electrolytic chromate treatment (Nα17°). 18) Tests on abrasion resistance, etc. were performed on samples coated with acrylic resin (Nα19, 20) and samples coated with ethyl silicate to form a metal oxide film (Null) after being colored by oxidation in the air. I did it. The results are summarized in Table 1 as a comparative example. Furthermore, Table 2 shows the results of testing the adhesion of the film for the above Examples and Comparative Examples.

■L Gloss Emperor Grain Capsule (A) Test method Abrasive paper [Namamugi 3M wrapping film (abrasive grain A1□
0. )] using a flat abrasion tester with a load of 300 kg.
The surface of the test piece was polished under the following conditions: f, reciprocating length of 30 mm, and number of wears of 300 times.

(Please) Evaluation criteria O: Surface scratches are not noticeable at all.

△: Surface scratches are slightly noticeable.

×: Surface scratches are extremely noticeable.

Test method A test piece was heated for 2 hours in an electric furnace at 800°C, and discoloration before and after heating was evaluated.

(ff) Evaluation criteria 0: No discoloration at all.

Δ: Slight discoloration.

X: Significant discoloration.

■m 玖简presentMeng (a) Test method: Apply artificial fingerprint liquid to a rubber stopper, and apply it to the surface of the test piece for a certain period of time at a pressure of 1 kg/m.

(0) Evaluation criteria ◎: No fingerprints attached.

○: Very slight fingerprint adhesion.

△: 50% of fingerprints adhered.

X: The entire fingerprint is attached.

U support ■ Yukasa 1 (a) Test method After testing the following items, turn the film side outward,
A taping test of cellophane adhesion and peeling was conducted on the test area, and the degree of peeling of the film was observed and evaluated.

(A) DuPont impact test (B) Erichsen extrusion test (4mm extrusion) (C)
90 degree bending test (bending radius: 8 mm) (b) Evaluation criteria ○: No peeling at all.

△Partial peeling.

X: Fully peeled off.

Claims (1)

[Claims] After a stainless steel plate is immersed in a mixed aqueous solution of chromic acid and sulfuric acid to form a colored oxide film on the surface of the steel plate, alkoxides of Si, Al, Ti, and Zr, acetylacetonate complexes, or octylic acid are applied to the surface of the film. Wear resistance characterized by forming an oxide film of the metal by applying an alcohol solution containing 0.05% by weight or more of at least one metal salt and heating at 200°C to 500°C.・Production method of colored stainless steel plate with excellent heat resistance and fingerprint resistance.