JPH0742599B2 - Method for electrolytically coloring aluminum or aluminum alloy - Google Patents

Description

The present invention relates to a method for electrolytically coloring aluminum or an aluminum alloy (hereinafter referred to as "aluminum"), and more specifically, a bright color tone having excellent weather resistance on the surface of aluminum. The present invention relates to an electrolytic coloring method for forming a film.

[Problems to be Solved by the Related Art and Invention] Generally, when electrolytic coloring treatment is performed on aluminum in an aqueous solution containing a copper compound or a selenium compound, in the case of an ordinary electrolytic solution containing a nickel salt, a cobalt salt, a tin salt, or the like, Unlike the brownish color tone obtained in the above, a bright colored film of green, red and yellow is obtained.

However, since these bright colored films have poor weather resistance, they are not suitable for building material products used outdoors. Therefore, conventionally, in order to improve the weather resistance, after the formation of the colored film, it is necessary to perform a sealing operation for a long time or perform a sealing operation in two steps.

Therefore, the present inventor has conducted earnest studies to develop a method for forming a bright colored film having excellent weather resistance on an aluminum surface by a simple operation.

[Means for solving problems]

As a result, they have found that the object can be achieved by electrolytically coloring anodized aluminum in an aqueous solution containing a copper compound or a selenium compound and then dipping it in a specific aqueous solution.

The present invention has been completed based on such findings.

That is, according to the present invention, anodized aluminum is electrolytically colored in an aqueous solution containing a copper compound and / or a selenium compound, and then immersed in an aqueous solution containing nickel ions and / or cobalt ions and fluorine ions. A method of electrolytically coloring aluminum is provided.

The aluminum used in the method of the present invention is anodized and has an anodized film formed on its surface. The conditions for the anodizing treatment are not particularly limited, and the usual conditions that have been widely used in the past are sufficient. For example, first, pretreatment such as degreasing, etching, and neutralization is performed according to the state of the aluminum surface, and then inorganic acids such as sulfuric acid, chromic acid, and phosphoric acid that form an anodized film, or oxalic acid, tartaric acid, and aromatic sulfone. Electrolysis is performed in an electrolytic bath composed of an aqueous solution containing an organic acid such as an acid. By this treatment, an anodized film is formed on the surface of aluminum.

In the method of the present invention, the anodized aluminum is first subjected to electrolytic coloring treatment. The electrolytic solution used for the electrolytic coloring treatment is an aqueous solution containing a copper compound and / or a selenium compound. As this copper compound,
Copper sulfate, copper nitrate, copper chloride, copper phosphate, copper pyrophosphate, copper acetate, copper formate, etc. are used, and selenium compounds include selenium dioxide, selenious acid, selenic acid and their sodium salts, ammonium salts. , Potassium salt, etc. are used.

The electrolytic solution may contain either a copper compound or a selenium compound, but both may be present together. Further, the concentrations of the copper compound and the selenium compound in this electrolytic solution may be appropriately selected according to the type of aluminum as the material, the state of the anodized film, the desired color tone of the colored film, etc., and should be uniquely determined. However, the concentration of copper is usually 1 to 50 g /, preferably 5 to 20 g /, and the concentration of selenium is 0.1 to 30 g /, preferably
It is 0.5 to 20 g /.

In the method of the present invention, electrolytic coloring treatment is performed using the above-mentioned electrolytic solution, but the conditions of this treatment may be selected according to the AC electrolytic coloring method that has been conventionally performed. Further, in the electrolytic coloring treatment, magnesium, nickel, tin, etc. may be present together with copper or selenium in the electrolytic solution.

Conditions for electrolytic coloring, such as AC voltage to be applied,
The energization time, liquid temperature, etc. may be appropriately selected as in the usual case. Specifically, the anodized aluminum is used as one electrode, and nickel, stainless steel, carbon, or the like is used as a counter electrode, and an alternating current or a waveform current having the same effect as the alternating current (for example, incomplete rectification) is used. .. Electrolysis temperature (bath temperature) is 10-40 ℃, especially 15-30 ℃
Is preferred, and the applied voltage is preferably 5 to 30V, particularly preferably 8 to 20V. Further, the electrolysis time is 0.5 to 30 minutes, preferably 3 to 10
It's a minute.

In the method of the present invention, the aluminum subjected to the above-mentioned electrolytic coloring treatment is washed with water as needed and then subjected to immersion treatment. This immersion treatment is performed by immersing the electrolytically colored aluminum described above in an aqueous solution containing one or both of nickel ions and cobalt ions and fluorine ions. Here, there are various sources of nickel ions, and examples thereof include nickel sulfate, nickel nitrate, nickel acetate, nickel chloride, and the like, and sources of cobalt ions include cobalt sulfate and cobalt nitrate. , Cobalt acetate, cobalt chloride, etc.

On the other hand, hydrofluoric acid,
Fluoride compounds such as sodium fluoride, ammonium fluoride and potassium fluoride and silicofluorides such as hydrosilicofluoric acid, sodium silicofluoride, ammonium silicofluoride and potassium silicofluoride are used.

The concentration of nickel ion, cobalt ion and fluorine ion in the aqueous solution used for the dipping treatment is not particularly limited, but generally nickel ion 0.5 to 10 g /, preferably 1 to 5 g /, cobalt ion 0.1 to 5 g /, Preferably
0.2 to 3 g /, and fluorine ion is 0.05 to 10 g /, preferably 0.1 to 5 g /.

The above-mentioned aqueous solution containing nickel ions and / or cobalt ions and fluorine ions is referred to as a low-temperature sealing agent or a room-temperature sealing agent, and is a hard wall 3 or a hard wall 5 (all manufactured by Nichika Chemical Co., Ltd.). , Anodal
CS-1, Anodal CS-2 (above, Sand Corp.) or
It is marketed under the trade name such as PEL81 (manufactured by Arsan).

In the dipping treatment, it is sufficient to immerse the electrolytically colored aluminum described above in the aqueous solution for a short time. The treatment conditions at this time may be a liquid temperature of 15 to 40 ° C. and a time of 5 to 20 minutes.

〔The invention's effect〕

According to the method of the present invention, a bright colored film having excellent weather resistance, which is based on a copper compound or a selenium compound, can be formed on the aluminum surface. Therefore, the electrolytically colored product of aluminum obtained by the method of the invention is
It can be used outdoors as a building material, etc., and there is no fear of fading for a long time.

〔Example〕

 Next, the present invention will be described in more detail with reference to examples.

Example 1 Electrolytic coloring solution containing 30 g of copper sulphate pentahydrate / 30 g / magnesium sulphate heptahydrate 20 g / and 5 g / sulfuric acid and having a pH of 1.0 was placed in a beaker of 5, and anodized A6063-T. A test piece of aluminum plate material No. ₅ (150 mm × 70 mm × 2 mm) was put in, a carbon plate was used as a counter electrode, an alternating current of 10 V was applied, and electrolytic coloring treatment was performed for 1 minute to obtain a bright red film.

Next, this test piece was used as a low-temperature sealing agent under the trade name "Hard Wall 3" (manufactured by Nichika Chemical Co., Ltd.) in an aqueous solution of 5 g / (including nickel ion of about 1.5 g / and fluorine ion of about 1 g /).
It was immersed therein at 30 ° C. for 15 minutes.

After the immersion, the test piece was placed in a sunshine carbon weather meter and irradiated for 500 hours.

As a result, the color difference before and after irradiation is ΔE = 1.26, which shows almost no change.

Comparative Example 1 The same operation as in Example 1 was carried out except that the test piece was immersed in boiling water (95 ° C.) of demineralized water for 25 minutes instead of being immersed in the aqueous solution of the low-temperature sealing agent. It was As a result, the color difference of the test piece before and after irradiation was large as ΔE = 4.77, and the test piece after irradiation was decolorized in a pale pink color.

Example 2 An electrolytic coloring solution containing 35 g of copper sulphate pentahydrate / 35 g of magnesium sulphate heptahydrate of 20 g / and 20 g of boric acid and having a pH of 4.0 was placed in a beaker of 5, and anodized A6063-T. _Five
Put a test piece of aluminum plate material (150 mm × 70 mm × 2 mm), and use a counter electrode as a carbon plate and apply an alternating current of 10 V for 1.5
An electrolytic coloring treatment was performed for a minute to obtain a young leaf color film.

Next, this test piece was used as a low temperature sealing agent under the trade name "Anodal CS-1" (made by Side Co.) in an aqueous solution of 15 g / (nickel ion: about 2.5 g /, cobalt ion: 400 ppm, fluorine ion:
(Including 600 ppm) at 32 ° C. for 20 minutes.

After the immersion, the test piece was put in a dew panel weather meter and irradiated for 1000 hours.

As a result, the color difference before and after irradiation was ΔE = 2.71 and it was found that there was almost no change.

Comparative Example 2 The same operation as in Example 2 was performed, except that the test piece in Example 2 was immersed in boiling water (95 ° C.) of demineralized water for 25 minutes instead of being immersed in the aqueous solution of the low-temperature sealing agent. It was As a result, the color difference of the test piece before and after irradiation was large as ΔE = 4.32, and the test piece after irradiation was decolored until almost no coloring was observed.

Example 3 An electrolytic coloring solution containing 30 g of copper sulphate pentahydrate / 20 g / magnesium sulphate heptahydrate 20 g / and 5 g / sulfuric acid and having a pH of 1.0 was placed in a beaker of 5, and anodized A6063-T. A test piece of aluminum plate material No. ₅ (150 mm × 70 mm × 2 mm) was put in, a counter electrode was a carbon plate, and 12 V AC was applied to perform electrolytic coloring treatment for 2 minutes to obtain a magenta film.

Then, this test piece was placed in an aqueous solution (including nickel ion approximately 1200 ppm, cobalt ion 350 ppm, and fluorine ion 800 ppm) of 5 g / product name "Hard Wall 5" (manufactured by Nichika Chemical Co., Ltd.), which is a low-temperature sealing agent. It was immersed at 35 ° C for 15 minutes.

After the immersion, the test piece was exposed outdoors for 3 months.

As a result, the color difference before and after irradiation was ΔE = 1.15, which shows almost no change.

Comparative Example 3 The same operation as in Example 3 was carried out except that the test piece was immersed in boiling water (95 ° C.) of demineralized water for 25 minutes instead of being immersed in the aqueous solution of the low-temperature sealing agent. It was As a result, the color difference before and after irradiation of the test piece was large, ΔE = 8.18, and the test piece after irradiation was decolorized in pink.

Example 4 A selenium dioxide 5 g /, magnesium sulfate heptahydrate 20 g / and sulfuric acid 5 g / and a pH 1.5 electrolytic coloring solution were placed in a 5 beaker and anodized A6063-T ₅ aluminum. A test piece of a plate material (150 mm × 70 mm × 2 mm) was put in, a carbon plate was used as a counter electrode, an alternating current of 10 V was applied, and electrolytic coloring treatment was performed for 5 minutes to obtain a leghorn-colored film.

Next, this test piece was used as a low-temperature sealing agent under the trade name "Anodal CS-2" (manufactured by Sand Co.) in an aqueous solution of 5 g / (nickel ion: about 2.4 g /, cobalt ion: 300 ppm, fluorine ion:
(Containing 900 ppm) at 30 ° C. for 15 minutes.

After the immersion, the test piece was put in a dew panel weather meter and irradiated for 1000 hours.

As a result, it can be seen that the color difference before and after irradiation is ΔE = 0.91, which shows almost no change.

Comparative Example 4 The same operation as in Example 4 was performed, except that the test piece in Example 4 was immersed in boiling water (95 ° C.) of demineralized water for 25 minutes instead of being immersed in the aqueous solution of the low-temperature sealing agent. It was As a result, the color difference of the test piece before and after irradiation was large as ΔE = 4.16, and the test piece after irradiation was decolorized to a pale color.

Example 5 Selenium dioxide 2 g /, nickel sulfate hexahydrate 20 g /, magnesium sulfate 20 g / and boric acid 30 g / are contained, and the pH is 4.5.
Put the electrolytic coloring solution of 5 in a beaker of 5 and anodize the aluminum plate material of A6063-T ₅ (150 mm x 70 mm
X 2 mm) test piece, and the counter electrode as a carbon plate,
An alternating current of 10 V was applied and electrolytic coloring treatment was performed for 30 seconds to obtain a reddish purple film.

Next, this test piece was put under the trade name "PEL8" which is a low temperature sealing agent.
1 "(manufactured by Arsan) 200 ml / aqueous solution (nickel ion about 1150 ppm, cobalt ion 300 ppm, fluorine ion about 110)
0 ppm) at 30 ° C. for 15 minutes.

After the immersion, the test piece was exposed outdoors for 3 months.

As a result, it can be seen that the color difference before and after irradiation is ΔE = 2.19, which shows almost no change.

Comparative Example 5 Instead of dipping the test piece in the aqueous solution of the low-temperature sealing agent in Example 5, the boiling water (95 ° C.) containing 7 g / in the trade name “Alumite Sealer LL” (manufactured by Nippon Kagaku Sangyo Co., Ltd.) was used. The same operation as in Example 5 was performed except that the substrate was immersed for 25 minutes. As a result, the color difference before and after irradiation of the test piece was large, ΔE = 5.48, and the test piece after irradiation was yellowed.

Claims (1)

[Claims] 1. An anodized aluminum or aluminum alloy is electrolytically colored in an aqueous solution containing a copper compound and / or a selenium compound, and then converted into an aqueous solution containing nickel ions and / or cobalt ions and fluorine ions. A method for electrolytically coloring aluminum or an aluminum alloy, which comprises immersing and dipping.