JPH042678B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for forming a colored coating on titanium or a titanium alloy material, and particularly to a method for forming a multicolored coating on the surface of a titanium or titanium alloy material.

[Conventional technology and its problems]

Titanium and titanium alloy materials (hereinafter referred to as titanium materials) are lightweight, high strength, and have excellent heat resistance and corrosion resistance, so they are used not only in electrical and mechanical parts, but also in decorations such as eyeglass frames and accessories. Demand in the field of products is increasing.

In such fields, coloring treatment is necessary to enhance the sense of luxury and fashionability. Conventionally, as methods for coloring titanium materials, in addition to atmospheric oxidation treatment and chemical conversion treatment, anodic oxidation treatment has been proposed, for example, in Japanese Patent Publication No. 57-43157.

However, atmospheric oxidation treatment is difficult to control the color tone due to the growth of the titanium film at high temperatures, and chemical conversion treatment is a chemical treatment using chemicals, so the color tone that can be obtained is limited. There's a problem. On the other hand, anodic oxidation treatment has the advantage that various color tones can be easily obtained. However, conventional anodizing treatment
Since this method uses a titanium material as an anode and electrolyzes it using an aqueous electrolytic bath, there is a problem that only one color tone can be obtained over the entire surface of the titanium material, and it is not possible to color the titanium material in multiple colors. However, it still could not be said to be sufficient in terms of commercial value.

[Means for solving problems]

The present invention was developed through research to solve the above-mentioned problems, and its purpose is to easily form a multicolored colored film with a clear interface on the surface of a titanium material. The purpose is to provide a method.

In order to achieve the above object, the present invention employs a method of coating a required portion of the surface of a titanium material with a conductive material, subjecting it to anodization treatment, and then removing the conductive material.

The present invention will be explained in detail below.

First, the present invention employs anodic oxidation treatment as a coloring method. As a coloring method, it is possible to use the above-mentioned atmospheric oxidation treatment or chemical conversion treatment, but these are not suitable because they each have the disadvantage of lacking flexibility in color tone control and freedom in color tone.

In the present invention, prior to this anodic oxidation treatment, important parts of the surface of the titanium material are coated with a conductive material of a desired size and shape (including figures, symbols, etc.). This conductive material may be any material such as paint, film, or sheet, and is brought into close contact with the titanium material by coating, pasting, spraying, or other methods depending on the characteristics of each material. Printing methods such as screen printing are also suitable for efficiency.

Next, anodic oxidation treatment is performed to obtain a colored film of any desired color tone. The conditions for the anodizing treatment are not particularly limited, and a titanium material may be used as the anode, an aqueous electrolytic bath equivalent to a conventional anodizing bath such as an aqueous phosphoric acid solution may be used, and a predetermined voltage depending on the desired color may be applied.

After this treatment, the conductive material is removed from the surface of the titanium material. The conductive material plays the role of a mask material in the anodizing treatment, and since the covered portion is not anodized, it is possible to obtain a titanium material product that is divided into at least two colors.

As a means for preventing anodic oxidation, it is also possible to use an electrically insulating material such as acrylic resin. However, in this case, the anodic oxidation bath liquid tends to enter the area around the coating of the acrylic resin, etc., resulting in blurring of the outline of the colored titanium pattern. Furthermore, the application of the anodic oxidation voltage generates heat on the surface of the titanium material, which tends to cause peeling of the acrylic resin and the like, and thereby cause blurring of the outline of the colored titanium pattern.

In the present invention, since a conductive material is used as the mask material, there is a locally narrow gap between the coating (coating material, wallet material, etc.) and the surface of the titanium material, which prevents the anodic oxidation bath solution from penetrating. However, because the current density on the surface of the titanium material in that area is low, anodization does not occur and the outline of the colored titanium pattern does not become blurred. Further, the heat generated between the titanium material and the coating due to energization is small, and the coating does not peel off due to this, so the outline of the colored titanium pattern is less likely to blur.

Therefore, the higher the conductivity of the conductive material, the more suitable it is, and at least the specific resistance is 1×10 ¹⁰ Ω・cm.
The following are preferred. Furthermore, since the anodic oxidation bath is water-soluble, the conductive material must be water resistant.

The above is the basic method of the present invention, but if necessary, after obtaining an arbitrary pattern through the above steps, anodization treatment may be performed again at a lower applied voltage than in the previous and subsequent steps. Thereby, an arbitrary color tone can be formed in the portion masked with the conductive material during the previous anodizing treatment. Therefore, by repeating this operation as many times as desired, it is possible to obtain a titanium material with a complex and varied multicolored pattern.

Furthermore, after the above treatment, the metal alkoxide glass may be subjected to a baking treatment, and since the metal alkoxide glass has little change in refractive index and has a low curing temperature of about 120°, the baking treatment will not damage the anodic oxide film. Therefore, it is possible to obtain a colored titanium material that is multicolored and has excellent durability such as color fastness, weather resistance, and abrasion resistance.

Next, examples of the present invention will be shown.

Example 1 () Alkali-degreased pure titanium plate (40 mml x 40
mmw x 1 mmt) was immersed in a mixed aqueous solution of 3% by weight hydrofluoric acid and 7% by weight hydrogen peroxide at 25°C for 2 minutes to pickle the surface and use it as a sample.

() After applying glass-based conductive paint (resistivity: 1×10 ⁶ Ω・cm) to the surface of the sample by baking a circle with a diameter of 15 mm, anodizing voltage of 110 V was applied in a 1 wt% phosphoric acid aqueous solution. was applied to perform anodic oxidation. When the glass-based conductive paint was then peeled off, a pink colored titanium plate containing uncolored circles with a diameter of 15 mm was obtained.

No color bleeding was observed at the interface between the colored and uncolored parts of this colored titanium plate.

Example 2 Using the blue titanium plate prepared in Example 1, anodization treatment was performed again in a 1% by weight phosphoric acid aqueous solution at an anodization voltage of 20V.

As a result, a pink-blue titanium plate containing blue circles with a diameter of 15 mm was obtained, and no discoloration of the pink portion or bleeding between the pink and blue interface colors was observed.

Example 3 A conductive rubber sheet (thickness:
0.1mm, specific resistance: 1×10 ⁵ Ω・cm) disk (diameter 15
mm), in a 1% by weight phosphoric acid aqueous solution,
Anodic oxidation was performed by applying an anodic oxidation voltage of 110V.
Next, when the conductive rubber sheet was peeled off, it had a diameter of 15 mm.
A pink colored titanium plate containing uncolored circles of mm was obtained.

No color bleeding was observed at the interface between the colored and uncolored parts of this colored titanium plate.

Example 4 Using the blue titanium plate prepared in the third example, 1
Anodization treatment was performed again at an anodic oxidation voltage of 20 V in a wt % phosphoric acid aqueous solution.

As a result, a pink-blue titanium plate containing blue circles with a diameter of 15 mm was obtained, and no discoloration of the pink portion or bleeding between the pink and blue interface colors was observed.

Comparative example Using acrylic resin for the sample of Example 1, the diameter was 15 mm.
After coating in a circular shape of mm, anodization treatment was performed in a 1% by weight phosphoric acid aqueous solution at an anodic oxidation voltage of 110V.
In this case, some peeling of the acrylic resin was observed during the anodizing treatment. When the acrylic resin was peeled off after the anodizing treatment, color bleeding at the old acrylic resin interface and pink coloration were observed in the area that was peeled off during the anodizing treatment.

〔Effect of the invention〕

As explained above, according to the present invention, an excellent effect can be obtained in that a colored titanium or titanium alloy material with a multicolored and clear interfacial contour, which has an excellent sense of luxury and fashionability, can be easily produced.

Claims (1)

[Claims] 1. A method for forming a colored film on a titanium material, which comprises coating a required portion of the surface of a titanium or titanium alloy material with a conductive material, subjecting it to anodization treatment, and then removing the conductive material.