JPS6210297A - Formation of coated film of titanium or titanium alloy - Google Patents

Abstract

PURPOSE:To form easily and uniformly a colored coated film having excellent weatherability by carrying out DC electrolysis with titanium or a titanium alloy as the anode in an electrolyte contg. an electrodeposition resin and an acid capable of forming a barrier-type anodized coated film. CONSTITUTION:DC electrolysis is applied to titanium or a titanium alloy with titanium or a titanium alloy as the anode in an electrolyte contg. an electrodeposition resin and an acid capable of forming a barrier-type anodized coated film. A water-soluble or water-dispersible resin such as acrylic, epoxy, urea, melamine, phenolic, alkyd and benzoguanamine resins is used as the electrodeposition resin and the concn. of the resin in the electrolyte is appropriately regulated to about 1-40wt%. Sulfuric acid, phosphoric acid, sulfamic acid, boric acid, monocarboxylic acid, dicarboxylic acid, oxycarboxylic acid, aliphatic or aromatic sulfonic acid, etc., are used as the acid and the concn. is appropriately controlled to about 0.1-2%.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for forming a film on titanium or a titanium alloy (hereinafter referred to as "titanium"). The present invention relates to a method for forming colored coatings, particularly beautiful colored coatings.

[Problems to be solved by conventional technology and invention] Titanium has the advantages of being light, strong, and rust-free, so its demand has increased significantly in recent years, and it is used in many applications such as eyeglass frames, camera bodies, tennis racket golf shafts, etc. Applications are expanding from consumer use to building materials.

Generally, in the case of consumer products that have been used in a later environment, the titanium material itself can withstand use sufficiently due to its own characteristics, but if decorative properties are required, various surface treatments are applied. For example, by chemically treating the titanium surface in a mixed aqueous solution of sodium phosphate, potassium fluoride, hydrogen fluoride, etc.
40% by electrolytic treatment in a solution such as sulfuric acid or phosphoric acid.
A thin film of 0 to 100 colors is formed to produce interference colors such as purple to pink. The thin film formed here works to strengthen the surface of the titanium material, but since it is an interference film, it easily discolors in outdoor environments.

Therefore, when titanium is used in the field of building materials, it is desired to form a coating on the titanium surface that does not easily discolor and has excellent weather resistance. Various methods have been considered for performing such surface treatment, but all of them have drawbacks such as difficulty in controlling color development and complicated treatment steps.

Therefore, the inventors of the present invention have conducted extensive research in order to overcome the drawbacks of the above-mentioned conventional techniques and to develop a method for forming a uniform colored film with excellent weather resistance through simple processing steps.

[Means for solving problems]

As a result, they discovered that by subjecting titanium to direct current electrolysis treatment in a specific electrolytic solution, a uniform colored film with excellent weather resistance and no discoloration could be formed on the surface of titanium. The present invention was completed based on this knowledge.

That is, the present invention performs a DC electrolytic treatment on titanium using the titanium as an anode in an electrolytic solution containing an electrodeposition resin and an acid capable of forming a barrier-type anodic oxide film, thereby forming a barrier-type anodic oxide film and an electrodeposited film. The present invention provides a method for forming a titanium film, which is characterized by simultaneously forming a paint film.

The method of the present invention can be applied to titanium as it is, but it can also be used with foreign substances attached to the surface.

It is also effective to perform pretreatment to remove impurities, altered layers, etc. and condition the base surface. There are many different pre-treatment methods that can be carried out here, and depending on the condition of the titanium surface, operations such as degreasing treatment or immersion treatment in a corrosive aqueous solution such as hydrofluoric acid may be performed depending on the condition of the titanium surface. All you have to do is Such immersion treatment is usually carried out in an aqueous solution containing hydrogen fluoride in an amount of 0.5 to 45% by volume, preferably 1 to 5% by volume, at a temperature of 5 to 80°C, preferably 15 to 30°C, for 10 seconds to The treatment may be carried out for 10 minutes, preferably 30 seconds to 2 minutes.

In the method of the present invention, untreated titanium or titanium pretreated as described above is used as an anode and subjected to direct current electrolysis treatment in an electrolytic solution. Here, the electrolytic solution contains an electrodepositing resin and an acid capable of forming a barrier type anodic oxide film. There are various types of resin for electrodeposition, and there are no particular restrictions, but generally, acrylic resins, epoxy resins, urea resins, melamine resins, phenolic resins, alkyd resins, acrylic-urethane resins, Acrylic-melamine resin, acrylic-alkyd resin, alkyd-melamine resin.

A water-soluble or water-dispersible electrodeposition resin such as an epoxy-melamine resin, a urea-melamine resin, or a benzoguanamine resin is used. The concentration of the electrodepositing resin in the electrolytic solution varies depending on the type of resin and other conditions and cannot be unambiguously determined, but it is usually 1 to 40% by weight, preferably 5 to 15% by weight as a resin solid content. Should.

Further, the electrolytic solution contains an acid capable of forming a barrier type anodic oxide film together with the electrodeposition resin described above. Here, the acid that can form a barrier type anodic oxide film refers to an acid that forms a barrier layer on the oxide film on the surface of titanium when titanium is anodized in an electrolytic solution containing this acid. Various inorganic and organic acids can be mentioned. Specifically, sulfuric acid, phosphoric acid, sulfamic acid, boric acid, monocarboxylic acids such as formic acid, acetic acid, and crotonic acid, dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, fumaric acid, and adipic acid, and malic acid. , tartaric acid,
Oxycarboxylic acids such as citric acid, methanesulfonic acid,
Aliphatic sulfonic acids such as ethanesulfonic acid, sulfosalicylic acid, toluenesulfonic acid, phenolsulfonic acid,
Aromatic sulfonic acids such as dinonylnaphthalenesulfonic acid, dodecylbenzenesulfonic acid, and cresolsulfonic acid can be mentioned. These acids may be used alone or in combination of two or more.

The concentration of the above-mentioned acid in the electrolytic solution may be appropriately selected depending on various situations (although it cannot be determined unambiguously, it is usually 0.1 to 2% by weight, preferably 0.2 to 1% by weight). It may be determined within the range of weight %.

The electrolytic solution used in the method of the present invention contains an acid capable of forming a barrier type anodic oxide film with the electrodepositing resin as described above, but if necessary, ammonia may be added to adjust the pH of the solution. or amines can also be added. In addition,
Some commercially available electrodeposition paints contain the acids mentioned above.
In this case, the solution containing this electrodeposition coating material can be used as the electrolytic solution of the present invention without adding an acid separately.

The electrolytic treatment using the above electrolytic solution is carried out by applying a direct current using titanium as an anode. The electrolytic conditions at this time are not particularly limited and vary depending on the type of electrolytic solution and the desired performance of the film to be formed, but usually the electrolytic temperature is 15 to 35°C, preferably 20 to 23°C, and the voltage is 10 to 35°C. Direct current may be applied at 350V, preferably 100 to 250V, for about 10 seconds to 5 minutes, preferably about 2 minutes to 3 minutes.

In the method of the present invention, a barrier type anodic oxide film and an electrodeposition coating film are simultaneously formed on the titanium surface by the above electrolytic treatment. Both coatings are formed simultaneously on the surface of titanium, but as a result, the barrier type anodic oxide coating is first formed on the titanium surface, and then the electrodeposited coating is formed on top of that. However, in the method of the present invention, since both of the above-mentioned films are formed in one electrolytic treatment, the operation is simple, and the bond between the two wave films to be formed can be formed sequentially in separate electrolytic treatments. It becomes stronger compared to
It forms a film with excellent weather resistance.

After the electrolytic treatment according to the method of the present invention, if necessary, the titanium material is washed with water and then baked and dried to uniformly form a coating with a beautiful color and excellent weather resistance on the titanium surface.

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

Specifically, the baking temperature is 100 to 250°C, preferably 1
10 minutes to 80 minutes at 30 to 220°C, preferably 20 minutes
It is sufficient to process for ~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 of a desired color on a titanium surface with a simple operation, and the formed film has extremely excellent weather resistance. becomes.

Furthermore, since [411,] is extremely simplified, it is an industrially advantageous method.

〔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 a hydrogen fluoride aqueous solution (liquid temperature 20° C.) with a concentration of 3% by volume for 60 seconds.

After thoroughly washing the pretreated titanium with water, add 1% by weight of sulfuric acid and an acrylic anionic electrodeposited resin (solid content: 8% by weight).
Using the titanium as an anode and titanium plated with platinum as a cathode in an electrolytic solution containing
Direct current electrolysis was performed at 20 μm for 3 minutes. After that, wash with water,
When baked and dried at 80° C. for 20 minutes, a uniform light bronze colored film with a coating thickness of 15 μm was formed on the titanium used for the anode.

The physical properties of the film formed on the titanium surface were measured. The results are shown in Table 1.

Example 2 In Example 1, the voltage of DC electrolysis was changed from 120V to 15V.
The same operation as in Example 1 was performed except that the voltage was changed to 0V. As a result, a uniform light bronze colored film with a coating thickness of 18 μm was formed on the titanium used for the anode. Also,
The physical properties of this film are shown in Table 1.

Example 3 In Example 1, the voltage of DC electrolysis was changed from 120V to 13V.
The same operation as in Example 1 was performed except that 0■ was used. As a result, a uniform light bronze-colored film with a coating thickness of 15 μm was formed on the titanium used for the anode. Further, the physical properties of this film are shown in Table 1.

Example 4 After thoroughly washing titanium pretreated in the same manner as in Example 1, 100 ff11 of a 10% by weight boric acid aqueous solution adjusted to pH 8 with aqueous ammonia was added to an acrylic anionic electrodeposition resin liquid (solid content). 8% by weight) 17! Using the above titanium as an anode and titanium plated with platinum as a cathode in an electrolytic solution containing a mixture of
DC electrolysis was performed for 3 minutes. After that, wash with water and 180℃
When dried by baking for 20 minutes, a uniform brownish-purple film with a thickness of 14 μm was formed on the titanium anode.

The physical properties of the film formed on the titanium surface were measured. The results are shown in Table 1.

Comparative Example 1 After sufficiently washing titanium pretreated in the same manner as in Example 1 with water, a sulfuric acid aqueous solution with a concentration of 15% by weight was used as an electrolyte.
In this electrolyte, the titanium was used as an anode and titanium plated with platinum was used as a cathode, and 20V was applied at a liquid temperature of 20°C.
Direct current electrolysis was performed for 1 minute. Thereafter, when thoroughly washed with water and dried, a uniform purple film was formed on the surface of the titanium used for the anode. Table 1 shows the results of measuring the physical properties of this film.

Comparative Example 2 In Comparative Example 1, the voltage of DC electrolysis was changed from 20V to 30V.
The same operation as in Comparative Example 1 was performed except that .

As a result, a uniform light blue film was formed on the surface of the titanium used for the anode.

Table 1 shows the results of measuring the physical properties of this film.

Comparative Example 3 In Comparative Example 1, the voltage of DC electrolysis was changed from 20V to IOV.
The same operation as in Comparative Example 1 was performed except that .

As a result, a uniform gold-colored film was formed on the surface of the titanium used for the anode. Table 1 shows the results of measuring the physical properties of this film.

Comparative Example 4 After performing DC electrolysis under the same conditions as Comparative Example 1, it was thoroughly washed with water, and then spray-painted with urethane paint, and then baked and dried at 130°C for 20 minutes, resulting in a uniform coating on the titanium surface. A purple film with a coating thickness of 10 μm was formed. Table 1 shows the results of measuring the physical properties of this film.

Comparative Example 5 In Comparative Example 4, the voltage of DC electrolysis was changed from 20V to 50V.
The same operation as in Comparative Example 4 was performed except that .

As a result, a light blue-green coating with a uniform coating thickness of 10 μm was formed on the titanium surface. Table 1 shows the results of measuring the physical properties of this film.

Comparative Example 6 In Comparative Example 4, the voltage of DC electrolysis was changed from 20V to 60V.
The same operation as in Comparative Example 4 was performed except that .

As a result, a light yellow film with a uniform coating thickness of 10 μm was formed on the titanium surface. Table 1 shows the results of measuring the physical properties of this film.

Table 1 *1: Sunshine weather test 250 hours (JI
Compliant with SH8602).

*2: Immersed in pure water 98-100"C for 4 hours (JIS
H5400).

Claims (4)

[Claims] (1) Direct current electrolytic treatment is performed on titanium or titanium alloy using the titanium or titanium alloy as an anode in an electrolytic solution containing an electrodepositing resin and an acid capable of forming a barrier-type anodic oxide film, resulting in barrier-type anodization. A method for forming a film on titanium or a titanium alloy, characterized by forming a film and an electrodeposited film at the same time. (2) The electrodepositing resin is an acrylic resin, an epoxy resin, a urea resin, a melamine resin, a phenol resin, an alkyd resin, an acrylic-urethane resin, an acrylic-melamine resin, an acrylic-alkyd resin, Alkyd-melamine resin, epoxy-melamine resin,
The method according to claim 1, wherein the resin is a urea-melamine resin or a benzoguanamine resin. (3) The method according to claim 1, wherein the acid capable of forming a barrier type anodic oxide film is sulfuric acid, phosphoric acid, sulfamic acid, or boric acid. (4) The method according to claim 1, wherein the acid capable of forming a barrier type anodic oxide film is a monocarboxylic acid, a dicarboxylic acid, an oxycarboxylic acid, an aliphatic sulfonic acid, or an aromatic sulfonic acid.