JP4612658B2 - Aluminum coloring method - Google Patents

Description

  The present invention relates to a method for coloring aluminum using a mixture of two different metal complex dyes.

  Conventionally, the coloring of aluminum is performed by energizing aluminum as an anode in an electrolytic solution containing water and an appropriate acid to form a porous aluminum oxide layer on the aluminum surface (hereinafter abbreviated as anodizing treatment), a metal complex dye, It has been carried out by using acid dyes, direct dyes and the like as colorants. For example, examples of the metal complex dye include dyes described in JP-B 61-60869 and JP-A 60-235867. In recent years, when anodized aluminum is colored black, with the diversification of demand, the stability of the color of the processed material and the continued use of the treatment bath are required in terms of running cost and wastewater problems.

  However, the black coloration of anodized aluminum using a colorant that has been conventionally used has a problem that the color of the processed product is not sufficiently stable due to the repeated use of the treatment bath for many times. It was.

  The present inventors completed the present invention as a result of intensive studies to solve the above-mentioned problems. That is, the present invention provides the following general formula (1)

と次の一般式（２）

And the following general formula (2)

｛一般式（１）及び一般式（２）の式中、ｍは１又は２であり、Ｘは、水素、ナトリウム、カリウム又はアンモニウムを表わし、Ｍは、クロム、コバルト又は鉄を表わす。｝で表わされる金属錯塩染料とを、７０〜９０重量部対３０〜１０重量部配合した染料組成物を用いることを特徴とする陽極酸化処理アルミニウムの着色方法である。

{In the formulas (1) and (2), m is 1 or 2, X represents hydrogen, sodium, potassium, or ammonium, and M represents chromium, cobalt, or iron. Is a coloring method of anodized aluminum characterized by using a dye composition containing 70 to 90 parts by weight and 30 to 10 parts by weight of a metal complex dye represented by the following formula.

  The aluminum coloring method of the present invention is sufficiently colored black even if a substance having dissolved aluminum or sulfate radicals accumulates in the dyeing bath. Therefore, the dyeing bath can be used many times, and labor and energy can be saved.

  Of the above general formula (1), chromium complex dyes are those known in JP-A-55-97492, etc., and among the above general formula (2), chromium complex dyes are those described in the Dye Handbook. However, when these dyes were used alone for the black coloring of anodized aluminum, a phenomenon was observed in which the initial black color of the treated product gradually changed to gray when the treatment bath was repeatedly used.

  The cause of this is not always obvious, but if the treatment bath (immersion bath) is used repeatedly, the immersion bath contains dissolved aluminum adhering to the anodized aluminum, substances having sulfate radicals, other metal salts, oils and fats, etc. These contaminants impede the coloration of the anodized aluminum, and the anodized aluminum coloration is considered to be a certain black color, resulting in poor appearance.

In the present invention, by using the metal complex dye represented by the general formula (1) and the general formula (2) in a ratio of 70 to 90 parts by weight to 30 to 10 parts by weight, continuous use of several tens of treatment baths is possible. However, when the compounding usage ratio of the metal complex dye represented by the general formula (1) is less than 70 parts, that is, when the compounding usage ratio of the metal complex dye represented by the general formula (2) is 30 parts or more. This is not preferable because the elution of the dye represented by the general formula (2) into the treatment bath (a discharge phenomenon) occurs.
If the dye of the general formula (1) is used in an amount exceeding 90 parts, that is, if the dye of the general formula (2) is used in an amount of less than 10 parts, a stable black colored product cannot be obtained.

Hereinafter, the present invention will be described in more detail by way of examples. In the text, parts and% mean parts by weight and% by weight.
Example 1
The following structural formula

で表わされるクロム錯塩染料（以下、クロム錯塩染料Ｎｏ．１という。）７０部と次の構造式

70 parts of a chromium complex dye represented by the following formula (hereinafter referred to as chromium complex dye No. 1) and the following structural formula

で表わされるクロム錯塩染料（以下、クロム錯塩染料Ｎｏ．２という。）３０部とを１リットルのボールミルに加え、約５時間混合し粉砕して染料組成物を得た（以下、染料組成物Ｎｏ．１という）。

30 parts of a chromium complex dye represented by the formula (hereinafter referred to as chromium complex dye No. 2) was added to a 1 liter ball mill, mixed for about 5 hours and pulverized to obtain a dye composition (hereinafter referred to as dye composition No. 2). .1).

Comparative Example 1
The chromium complex dye No. 1 used in Example 1 was used. 1,100 parts were treated in exactly the same manner as in Example 1 to obtain a dye powder (hereinafter referred to as Comparative Dye No. 1).

Example 2
The following structural formula

で表わされるクロム錯塩染料（以下、クロム錯塩染料Ｎｏ．３という）８０部と、実施例１で用いたクロム錯塩染料Ｎｏ．２、２０部とを１リットルのボールミルに加え、実施例１と同様に処理して染料組成物（染料組成物Ｎｏ．２）を得た。

80 parts of a chromium complex dye (hereinafter referred to as “chromium complex dye No. 3”) and the chromium complex dye No. 3 used in Example 1. 2, 20 parts were added to a 1 liter ball mill and treated in the same manner as in Example 1 to obtain a dye composition (dye composition No. 2).

Comparative Example 2
The chromium complex dye No. 2 used in Example 2 was used. 3, 100 parts were treated exactly the same as in Example 2 to obtain a dye powder (Comparative Dye No. 2).

Example 3
Using the dye compositions obtained in Examples 1 and 2 and Comparative Examples 1 and 2 and the comparative dye, the anodized aluminum was repeatedly colored in an immersion bath. Express the result.

In addition, the colored product of the anodized aluminum test piece was obtained as follows. A 3 mm thick piece of aluminum (purity 99.85%) was anodized in a 20% sulfuric acid aqueous solution at a temperature of 20 ° C., 10 dm ² / А, and 14 V for 45 minutes. An aluminum piece having an oxide film layer was obtained. Separately, using the dyes obtained in Examples 1 and 2 and Comparative Examples 1 and 2, 1.0% dye baths were prepared, and the above aluminum pieces were immersed in these dye baths, pH 5.5, Coloring was performed at a temperature of 60 ° C. for 15 minutes. In the second and subsequent coloring, the coloring operation was repeated by adjusting the dye concentration in the dyeing bath to 1.0%. Therefore, 150 dm ^{2 in} Table 1 means that this coloring operation was repeated 15 times.

  In the table, the light fastness value was determined using a fade scale for color fading after irradiating a colored aluminum test piece for 256 hours with a fadeometer (light source, carbon arc lamp). The heat resistance value was determined on a gray scale after a colored aluminum test piece was treated at 200 ° C. for 5 hours.

  As is apparent from the table, the dye composition No. 1, no. When No. 2 was used, even if it was repeatedly colored a number of times (15 times), it exhibited an excellent black color and was also excellent in light resistance and heat resistance. In comparison, comparative dye no. 1, no. In the case of 2, when the coloring was repeated 5 to 10 times, the hue did not become gray and black, and the light resistance and heat resistance also decreased, which was practically inferior to the colorant according to the present invention.

  In addition, the accumulated amount of dissolved aluminum and sulfate radicals in the dyeing bath during repeated use was measured. The results are shown in Table 2.

Claims (4)

The following general formula (1)

And the following general formula (2)

{In the formulas (1) and (2), m is 1 or 2, X represents hydrogen, sodium, potassium, or ammonium, and M represents chromium, cobalt, or iron. } The coloring method of the anodized aluminum characterized by using the dye composition which mix | blended 70-90 weight part vs. 30-10 weight part with the metal complex salt dye represented by these.   2. The method for coloring anodized aluminum according to claim 1, wherein M in the general formulas (1) and (2) is chromium.   2. The method for coloring anodized aluminum according to claim 1, wherein M in the general formulas (1) and (2) is cobalt.   2. The method for coloring anodized aluminum according to claim 1, wherein M in the general formulas (1) and (2) is iron.