JPS6210299A - Formation of colored coated film for titanium or titanium alloy - Google Patents

Abstract

PURPOSE:To form the titled colored coated film having excellent weatherability and an excellent color tone uniformly, beautifully and easily by forming a colored coated film on titanium or a titanium alloy and then coating a transparent paint. CONSTITUTION:After titanium or a titanium alloy is degreased as required, chemical conversion treatment, anodization, etc., are applied to the titanium material to form a colored coated film. Then the material is washed with water as required and then transparent coating such as spray coating, electrostatic coating, dip coating and electrodeposition coating is carried out. Furthermore, the coat is, if necessary, baked and cured. By such treatment, the desired colored coated film of a vivid elementary color with a metallic feeling and having excellent weatherability is formed on the surface of the titanium, etc. uniformly and beautifully, by comparatively simple operation.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for forming a colored film on titanium or a titanium alloy (hereinafter referred to as "titanium"). By doing
This invention relates to a method for forming a beautiful coating with good weather resistance on a titanium surface.

[Problems to be solved by the conventional technology and invention] More than 20 years have passed since aluminum was used as a building material, and during that time the market for aluminum has rapidly increased due to its excellent workability and weather resistance. It has expanded.

On the other hand, with the recent diversification of living lifestyles, various performances are required of building materials. Moreover, especially the design,
In particular, the demand for color tone has become extremely large.

Conventional methods for coloring aluminum building materials include AC electrolytic coloring, electrolytic coloring, and painting methods, but even with AC electrolytic coloring, which is said to be the most superior in terms of weather resistance and economic efficiency, The fundamental drawback is that only bronze to black color tones can be obtained. In addition, with the electrolytic coloring method, it is possible to color in gray tones in addition to bronze, but it requires the use of a special aluminum alloy and the operation under special conditions.

Furthermore, although painting methods allow for coloring in various tones, the metallic feel is erased and the texture of the material cannot be utilized.

Therefore, the present inventor focused on using titanium material as a building material instead of aluminum material, and conducted extensive research. During the research process, titanium was found to be lightweight, strong, and non-rusting, making it ideal as a building material, and it can also be colored in a variety of colors through chemical conversion and electrolytic treatments. However, this colored film is usually 400 to 1000 people and is very thin.
It was found that it easily discolored or bleached in outdoor environments, making it unsuitable for practical use.

Based on these facts, the inventor of the present invention continued his research and discovered that if a colored film is formed on titanium and then a transparent coating is applied, weather resistance etc. are surprisingly improved significantly. , we have completed the present invention.

[Means for solving problems]

That is, the present invention provides a method for forming a colored film on titanium, which is characterized in that titanium is subjected to a colored film forming process and then a transparent coating process is performed on titanium.

The method of the present invention can be applied to titanium without any surface treatment, but in order to remove foreign matter, impurities, altered layers, etc. attached to the surface and adjust the base surface. It is also effective to perform pretreatment. There are various methods for pretreatment, and there are no particular limitations, such as puff polishing, blast polishing, degreasing, and immersion in a corrosive aqueous solution such as hydrofluoric acid. All you have to do is operate. The immersion treatment as such pretreatment is usually carried out at a temperature of 5% in an aqueous solution containing hydrogen fluoride in an amount of 0.5 to 45% by volume, preferably 1 to 5% by volume.
The treatment may be carried out at ~80°C, preferably 15~30°C, for 10 seconds to 10 minutes, preferably 30 seconds to 2 minutes. At this time, along with the above hydrogen fluoride in the aqueous solution,
Nitric acid, hydrochloric acid.

It is also possible to mix sulfuric acid, oxalic acid, formic acid, etc.

In the method of the present invention, untreated titanium or titanium that has been pretreated as described above is first subjected to a colored film forming treatment. This colored film forming treatment can be performed by various methods, and specific examples include chemical conversion treatment and anodic oxidation treatment. There are various types of chemical conversion treatments, and the conditions can be selected appropriately depending on the desired color tone, but in general, titanium is immersed in an acidic solution, a neutral solution, or an alkaline solution at room temperature or elevated temperature. do it. for example,
Sodium phosphate 1-10% by weight, preferably 4-6% by weight, potassium fluoride 1-5% by weight, preferably 1-2%
% by weight and 1-5% by volume of hydrogen fluoride, preferably 1-5% by volume.
In an aqueous solution containing 2% by volume, at a temperature of 20 to 80°C,
Preferably, titanium may be immersed at 20 to 30°C for 1 to 30 minutes, preferably 1 to 3 minutes.

On the other hand, anodizing treatment can also be carried out under various conditions.
The acids in the electrolyte used here include various non-acids and organic acids. Specifically sulfuric acid.

Phosphoric acid, sulfamic acid, boric acid, and formic acid.

Monocarboxylic acids such as acetic acid and crotonic acid, dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, fumaric acid, and adipic acid, oxycarboxylic acids such as malic acid, tartaric acid, and citric acid, and methanesulfonic acid.

Examples include aliphatic sulfonic acids such as ethanesulfonic acid and sulfamino acid, aromatic sulfonic acids such as sulfosalicylic acid, toluenesulfonic acid, phenolsulfonic acid, dinonylnaphthalenesulfonic acid, dodecylhenzensulfonic acid, and cresolsulfonic acid. . These acids may be used alone (or two or more types may be used in combination).

The concentration of the above-mentioned acid in this electrolytic solution varies depending on the type of acid and cannot be determined uniquely, but it is usually set in the range of 1 to 40 w/v%, preferably 5 to 20 w/v%. The pH of the electrolyte may be adjusted as necessary.
Ammonia and amines can also be added to adjust the

When anodizing using the above electrolytic solution, it is sufficient to use titanium as an anode and apply a direct current, but the electrolytic conditions at this time are usually an electrolytic temperature (solution temperature) of 0 to 60.
°C1 preferably 15~30゛C1 current density 0.1~5
A/dm", 10 seconds under the conditions of voltage 5-250■
Direct current may be applied for 3 minutes, preferably about 30 seconds to 1 minute.

In the method of the present invention, titanium that has been subjected to a colored film forming treatment such as a chemical conversion treatment or an anodizing treatment as described above must be washed with water as necessary, and then further subjected to a transparent coating treatment.

This coating treatment can be performed by various methods.

Among them, electrodeposition coating using water-based electrodeposition paint has the problem of high equipment costs, but it provides a good working environment and the resulting coating film has a uniform thickness and good adhesion. Therefore, it is preferable.

After painting by the method of the present invention, if necessary, wash with water,
Further, by performing a baking hardening treatment, a coating with a beautiful color tone and excellent weather resistance is uniformly formed on the titanium surface.

Note that this baking hardening treatment may be performed under normal conditions.

Specifically, the baking temperature is 100 to 250°C, preferably 1
IO minutes to 80 minutes at 30 to 220°C, preferably 2
What is necessary is to process for 0 to 30 minutes.

〔Effect of the invention〕

As described above, according to the method of the present invention, it is possible to uniformly and beautifully form a colored film in a desired primary color system with a bright metallic tone on a titanium surface with a relatively simple operation, and moreover, it is possible to form a colored film uniformly and beautifully on a titanium surface. The resulting coating has excellent weather resistance.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples.

Example 1 Industrially pure titanium (TIB) was washed with acetone, and then pretreated by immersing it in an aqueous hydrogen fluoride solution (liquid temperature: 25° C.) with a concentration of 5% by volume for 30 seconds.

After thoroughly washing the pretreated titanium with water, the concentration is 10% by weight.
Using the titanium as an anode and platinum-plated titanium as a cathode in an electrolytic solution consisting of an aqueous sulfuric acid solution,
Anodic oxidation treatment was performed by applying direct current at 10 V for 1 minute at a liquid temperature of 0°C.

Next, after washing the anodized titanium with water, it was electrocoated in an electrolytic solution containing acrylic electrocoating paint (solid content: 8% by weight) at 20°C, 120V, and for 3 minutes. .

Thereafter, it was washed with water and further subjected to baking hardening treatment at 180°C for 30 minutes, and a uniform gold-colored film with a metallic tint was formed on the titanium surface with a thickness of 15 μm.

In addition, a sunshine weather test (250 hours, JIS H860) was conducted to measure the weather resistance of this coating.
2), no abnormalities were observed in the coating.

Example 2 The same operation as in Example 1 was performed, except that the electrolyte used in the anodizing treatment was a tartaric acid aqueous solution with a concentration of 5% and the voltage for the anodizing treatment was 30 V. . As a result, a uniform light blue film with a metallic tint was formed on the titanium surface with a film thickness of 15 μm.

Moreover, no abnormalities were observed in the sunshine weather test results of this coating.

Example 3 Titanium pretreated in the same manner as in Example 1 was thoroughly washed with water, and then anodized using an electrolytic solution consisting of an oxalic acid aqueous solution with a concentration of 1% by weight, but under the same conditions as in Example 1. .

Next, after washing the anodized titanium with water, it was electrostatically painted using a urethane paint.

Thereafter, a baking hardening treatment was performed at 130° C. for 30 minutes, and a uniform gold-colored film with a metallic feel was formed on the titanium surface with a thickness of 10 μm. Moreover, no abnormalities were observed in the sunshine weather test results of this coating.

Example 4 In Example 1, the electrolytic solution used for anodizing treatment was a sulfamic acid aqueous solution with a concentration of 5% by weight, the voltage for anodizing treatment was 40 V, and the voltage for electrodeposition coating was 140 ■. Except for this, the same operation as in Example 1 was performed.

As a result, a uniform blue-green coating with a metallic feel was formed on the titanium surface with a thickness of 18 μm. Moreover, no abnormalities were observed in the sunshine weather test results of this coating.

Example 5 After thoroughly cleaning titanium that had been pretreated in the same manner as in Example 1, an anode was prepared under the same conditions as in Example 1 except that an electrolytic solution consisting of a phosphoric acid aqueous solution with a concentration of 10% by weight was used and the voltage was set to 90 V. Oxidation treatment was performed.

Next, the anodized titanium was washed with water and then subjected to dip coating using an acrylic paint.

Thereafter, a baking hardening treatment was performed at 180° C. for 30 minutes, and a uniform orange film with a metallic feel was formed on the titanium surface with a thickness of 8 μm.

Moreover, no abnormalities were observed in the sunshine weather test results of this coating.

Example 6 In Example 1, except that the electrolytic solution used for the anodizing treatment was a formic acid aqueous solution with a concentration of 5%, the voltage for the anodizing treatment was 30 V, and the voltage for the electrodeposition treatment was 100 V. The same operation as in Example 1 was performed.

As a result, a uniform blue film with a metallic feel was formed on the titanium surface with a film thickness of 15 μm.

Moreover, no abnormalities were observed in the sunshine weather test results of this coating.

Example 7 After thoroughly washing titanium pretreated in the same manner as in Example 1, an anode was prepared under the same conditions as in Example 1 except that an electrolytic solution consisting of an aqueous sulfosalicylic acid solution with a concentration of 5% by weight was used and the voltage was set to 20 V. Oxidation treatment was performed.

Thereafter, electrostatic coating treatment and baking hardening treatment were performed in the same manner as in Example 3. As a result, a film thickness of 8 μm was obtained on the titanium surface.
A uniform blue-purple film with a metallic feel was formed. In addition, this coating has sunshine weather protection.
The test results showed no abnormality at all.

Example 8 After thoroughly washing titanium pretreated in the same manner as in Example 1, 5% by weight of sodium phosphate and double % of potassium fluoride were added.
and 13 mjl of 46% hydrofluoric acid! /β was immersed in an aqueous solution (liquid temperature: 20° C.) to perform chemical conversion treatment for 3 minutes.

Next, after washing the chemically treated titanium with water, it was subjected to dip coating using an acrylic paint.

Thereafter, a baking hardening treatment was performed at 180° C. for 30 minutes, and a uniform green-brown film with a metallic feel was formed on the titanium surface with a thickness of 8 μm. Moreover, no abnormalities were observed in the sunshine weather test results of this coating.

Comparative Example 1 After thoroughly cleaning titanium pretreated in the same manner as in Example 1, an anode was prepared under the same conditions as in Example 1 except that an electrolytic solution consisting of an aqueous phosphoric acid solution with a concentration of 10% by weight was used and the voltage was set to 90 V. Oxidation treatment was performed. As a result, an orange film was formed on the titanium surface, but a sunshine weather test of this film showed discoloration or decolorization of the film.

Comparative Example 2 After thoroughly washing titanium pretreated in the same manner as in Example 1, an anode was prepared under the same conditions as in Example 1 except that an electrolytic solution consisting of an aqueous sulfosalicylic acid solution with a concentration of 5% by weight was used and the voltage was set to 20 V. Oxidation treatment was performed. As a result, a blue-purple film was formed on the titanium surface, but a sunshine weather test of this film showed discoloration or decolorization of the film.

Comparative Example 3 After thoroughly washing titanium pretreated in the same manner as in Example 1, anodizing was carried out under the same conditions as in Example 1 except that an electrolyte consisting of an aqueous tartaric acid solution with a concentration of 5% by weight was used and the voltage was set to 30 V. processed. As a result, a blue film was formed on the titanium surface, but a sunshine weather test of this film showed discoloration or decolorization of the film.

Comparative Example 4 Pretreatment and anodic oxidation treatment were performed in the same manner as in Example 1,
A gold-colored film was formed on the titanium surface. When this coating was subjected to a sunshine weather test, discoloration or decolorization of the coating was observed.

Claims (4)

[Claims] (1) A method for forming a colored film on titanium or a titanium alloy, which comprises subjecting titanium or a titanium alloy to a colored film forming process and then applying a transparent coating process. (2) The method according to claim 1, wherein the colored film forming treatment is a chemical conversion treatment. (3) The method according to claim 1, wherein the colored film forming treatment is an anodic oxidation treatment. (4) The method according to claim 1, wherein the coating treatment is a spray coating treatment, an electrostatic coating treatment, a dip coating treatment, or an electrodeposition coating treatment.