JPH09302256A - Dye composition and method for coloring aluminum using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a dye compsn. which can offer a stable hue in black coloring of anodized aluminum and enables repeated use of a dyeing bath by comprising two different metal complex salt dyes. SOLUTION: Metal complex salt dyes represented by formulae I and II [(m) is 1 or 2; X represents H, sodium, potassium, or ammonium; M represents chromium, cobalt, or iron] are mixed together in respective amts. of 70 to 90 pts.wt. and 30 to 10 pts.wt. to prepare a dye compsn. This dye compsn. is used to color anodized aluminum black. The dye compsn. can offer satisfactory black coloring even when dissolved aluminum and a material having a sulfate group are accumulated, making it possible to repeatedly use a dyeing bath a plurality of times, which contributes to labor saving and energy saving.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for coloring aluminum which is used by blending two different kinds of metal complex salt dyes.

[0002]

2. Description of the Related Art Conventionally, for coloring aluminum, electricity is applied in an electrolytic solution containing water and a suitable acid by using aluminum as an anode to form a porous aluminum oxide layer on the surface of aluminum (hereinafter referred to as anodizing treatment). ) It has been carried out by using a metal complex salt dye, an acid dye, a direct dye or the like as a colorant. Examples of the metal complex salt dye include dyes described in JP-B-61-60869 and JP-A-60-235867. In recent years, when anodized aluminum is colored black, the stability of the color of the treated material and the continuous use of the treatment bath are required from the viewpoints of running cost and waste water problems, as the demand diversifies.

[0003]

However, in the black coloring of anodized aluminum using a coloring agent that has been conventionally used, the coloring of the treated product is sufficient because the treatment bath is repeatedly used many times. There was a problem that it was not stable.

The present inventors have completed the present invention as a result of earnest research to solve the above problems. That is, the present invention provides the following general formula (1)

[0005]

Embedded image And the following general formula (2)

[0006]

[Chemical 6] {In the formulas (1) and (2), m is 1 or 2
And X represents hydrogen, sodium, potassium or ammonium, and M represents chromium, cobalt or iron. } And a metal complex salt dye represented by the following formula: 70 to 90 parts by weight vs. 30 to 10 parts by weight, and an anodized aluminum characterized by using this dye composition. Is a coloring method.

Among the general formula (1), the chromium complex salt dye is known in JP-A-55-97492, and the chromium complex salt dye in the general formula (2) is described in Dye Handbook or the like. However, when these dyes were used alone to color black 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 is not always clear, but when the treatment bath (immersion bath) is repeatedly used many times, dissolved aluminum adhering to anodized aluminum in the immersion bath, a substance having a sulfate group, and other metal salts. It is considered that oils and fats and the like are mixed in, and these mixed substances hinder the coloring of the anodized aluminum, and the anodized aluminum colored material does not become a certain black color and a poor appearance occurs.

In the present invention, the general formula (1) and the general formula (2)
70 to 90 parts by weight of the metal complex dye represented by
By blending in a proportion of 10 parts by weight, the treatment bath can be continuously used for several tens of times, but when the blending proportion of the metal complex salt dye represented by the general formula (1) is less than 70 parts, that is, in general When the compounding ratio of the metal complex salt dye represented by the formula (2) is 30 parts or more, the dye represented by the general formula (2) elutes into the treatment bath (a bleeding phenomenon), which is not preferable. If the dye of the general formula (1) is used in excess of 90 parts, that is, if the dye of the general formula (2) is used in less than 10 parts, a stable black colored product cannot be obtained.

[0010]

EXAMPLES The present invention will be described in more detail with reference to examples below, where “parts” and “%” mean “parts by weight” and “% by weight”. Example 1 The following structural formula

[0011]

[Chemical 7] Chromium complex salt dye represented by
o. 1 ) 70 parts and the following structural formula

[0012]

Embedded image Chromium complex salt dye represented by
o. Two. ) 30 parts were 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. 1).

Comparative Example 1 Chromium complex salt dye No. 1 used in Example 1 Dye powder was obtained by treating 1,100 parts in exactly the same manner as in Example 1 (hereinafter,
Comparative dye No. 1).

Example 2 The following structural formula

[0015]

Embedded image Chromium complex salt dye represented by
o. 80 parts) and the chromium complex salt dye No. 3 used in Example 1. 2 and 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 salt dye No. 1 used in Example 2 was used. 3, 100 parts were treated in exactly the same manner as in Example 2 to obtain a dye powder (Comparative Dye N
o. 2) was obtained.

Example 3 Dye compositions obtained in Examples 1-2 and Comparative Examples 1-2,
Anodized aluminum was dipped in the immersion bath using the comparative dye a number of times. Describe the result.

[0018]

[Table 1]

The colored product of the anodized aluminum test piece was obtained as follows. A piece of aluminum (purity 99.85%) with a thickness of 3 mm was placed in a 20% aqueous solution of sulfuric acid at a temperature of 20 ° C., 10 dm ² / А, and 14 V.
Anodizing for 45 minutes, oxide film thickness, 15
An aluminum piece having a μ oxide layer was obtained. Separately, the dyes obtained in Examples 1 and 2 and Comparative Examples 1 and 2 were used to prepare 1.0% dyeing baths, and the aluminum pieces were immersed in these dyeing baths to give a pH of 5.5. Coloring was performed under the conditions of a temperature of 60 ° C. and a time of 15 minutes. The second and subsequent colorings were adjusted so that the dye concentration in the dyeing bath was 1.0%, and the coloring operation was repeated. Therefore, in Table 1, 150d
m ² means that this coloring operation was repeated 15 times.

In the table, the light resistance value was measured using a colored aluminum test piece with a fade odometer (light source, carbon arc lamp) 25.
After irradiation for 6 hours, the color was evaluated by the color change and proof scale. The heat resistance value was evaluated on a gray scale after treating a colored aluminum test piece for 5 hours at 200 ° C.

As is apparent from the table, the dye composition No. 1 of the present invention was used. 1, No. If 2 is used, a large number of times (1
(5 times) Even after repeated coloring, it exhibits an excellent black color,
Furthermore, it was excellent in light resistance and heat resistance. In comparison, comparative dye No. 1, No. In the case of 2, when it was repeatedly colored 5 to 10 times, the hue was gray and did not become black, and further the light resistance and heat resistance were lowered, which was inferior to the colorant according to the present invention in practical use.

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

[0023]

[Table 2]

[0024]

EFFECTS OF THE INVENTION The dye composition of the present invention is colored sufficiently black even if a substance having dissolved aluminum or a sulfate group is accumulated in the dye bath. Therefore, the dyeing bath can be used many times, which enables labor saving and energy saving.

[Table-1]

[Table-2]

Claims (4)

[Claims] 1. The following general formula (1): And the following general formula (2) {In the formulas (1) and (2), m is 1 or 2
And X represents hydrogen, sodium, potassium or ammonium, and M represents chromium, cobalt or iron. } And a metal complex salt dye represented by the following formula: 70 to 90 parts by weight vs. 30 to 10 parts by weight. 2. The dye composition according to claim 1, wherein M in the general formula (1) and the general formula (2) in claim 1 is chromium. 3. The following general formula (1): And the following general formula (2) {In the formulas (1) and (2), m is 1 or 2
And X represents hydrogen, sodium, potassium or ammonium, and M represents chromium, cobalt or iron. } The dyeing composition which mix | blended 70-90 weight part with 30-10 weight part of the metal complex dye represented by these is used, The coloring method of the anodized aluminum. 4. The method for coloring anodized aluminum according to claim 3, wherein the compounded dye composition is a chromium complex salt dye.