JPS6361978B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel 1:2 type chromium complex salt compound and a method for coloring aluminum using the compound. Conventionally, aluminum has been colored using an acid dye, an acid mordant, and the like, after forming a fine porous aluminum oxide film by applying electricity to an aluminum anode in an aqueous solution containing an appropriate acid (hereinafter abbreviated as anodizing treatment). This was done by immersing anodized aluminum in an aqueous solution of dyes, direct dyes, oil-soluble dyes, metal complex dyes, etc. at an appropriate temperature, pH, and time. However, in the anodizing treatment using these conventional colorants, it has not been found that the hue, light resistance, heat resistance, elution (weeping) of the colorant during hot water washing after coloring, or elution (weeping) of the colorant during sealing are sufficiently satisfactory. do not have. The present inventors completed the present invention as a result of extensive research into colorants, particularly black colorants, that can satisfactorily satisfy these various performances. That is, the present invention is based on the following general formula {In the formula, A is a phenyl group or a naphthalene group having the following structure.

[expression] or

[Formula] (Here, X ₁ , X ₂ , X ₃ and X ₄ represent a hydrogen atom or a sulfonic acid group.) Z represents hydrogen, sodium, potassium or ammonium ion, and n represents an integer. } A 1:2 type chromium complex salt compound represented by the following and a method for coloring aluminum using the compound. The symmetrical 1:2 type chromium complex salt compound represented by the above general formula (1) can be obtained by diazotizing sulfanilic acid, for example, and diazotizing the corresponding aminonaphtholsulfonic acid (J
A monoazo dye was synthesized by coupling 4,6 with a weakly acidic acid, and then diazotized with a weakly alkaline solution.
A disazo mordant is synthesized by coupling with -dinitro-2-aminophenol (picramic acid), and this is complexed with a chromium-imparting agent such as chromium acetate or chromium sulfate by a conventionally known method, and after the reaction is completed, acetic acid is added. The desired product can be obtained by salting out with sodium etc., filtering and drying. Coloring of anodized aluminum using this 1:2 type chromium complex compound is carried out by a conventionally known method. For example, the above in water and organic solvents such as alcohol, ethylene glycol, etc.
Although the anodized aluminum can be colored by dissolving the 1:2 type chromium complex compound of formula (1) and applying or spraying, a particularly preferred coloring method is to dissolve the 1:2 type chromium complex compound of formula (1). This method involves immersing anodized aluminum in an aqueous solution. This coloring method by dipping can be carried out at a temperature ranging from room temperature to the boiling point, but a temperature range of 40° C. to 70° C. is particularly preferable, and it is desirable that the pH of the dipping bath is maintained at 5.0 to 6.0. The immersion time varies depending on the intended coloring density and the thickness of the aluminum anodized film, but is generally 1 to 30 minutes, preferably 15 to 20 minutes. In this case, the aluminum referred to in the present invention includes not only pure aluminum but also Al-Mg, Al-Si, Al-Mg-
Si, Al―Zn―Mg, Al―Cu―Mg, and Al―
It is an alloy of aluminum and various metals such as Zn-Mg-Cu, which means that it can be anodized in the same way as pure aluminum. As the acid used in this anodic oxidation treatment of aluminum, known acids such as oxalic acid, sulfuric acid, or a mixed acid thereof can be used. When the chromium complex compound represented by the general formula (1) of the present invention is used alone to color anodized aluminum, a highly concentrated black colored product is obtained. Various performances such as bleeding during washing with hot water and bleeding during sealing are very excellent as detailed in the following examples. Traditionally, the black coloring of aluminum was yellow,
This was done by combining red and blue dyes, but in such cases, the disadvantage is that the hue tends to blur due to the difference in dyeing speed of each dye, and furthermore, the repeated use of the dipping bath also causes the hue to change. This was impossible because it would cause turbulence. In the method for coloring aluminum of the present invention, the above general formula (1) is used.
Since a single chromium complex salt compound represented by is used, there was no problem of color blurring, and the dipping bath could be used many times. The present invention will be explained in more detail with reference to Examples below. In addition, "part" and "%" in the text mean parts by weight and weight %. Example 1 An aqueous solution of 47.8 parts of 6-amino-1-naphthol-4-sulfonic acid (J acid) dissolved in pH 6 was heated at 5°C.
34.6 parts of diazotized P-sulfoaniline (sulfanilic acid) was added at once to this solution. Next, the pH was adjusted to 3 to 4 with sodium acetate, and coupling was performed. After coupling, add 44.2 parts of 4,6-dinitro to the reaction solution at 5°C or below.
Add diazotized product of 2-aminophenol (sodium picramate), then adjust the pH to 8~8 with caustic soda.
I adjusted it to 9.5 and did some coupling. After coupling, salt out with sodium chloride,
Disperse the resulting wet cake in water and add 22.9
of chromium acetate was added. After adjusting the pH to around 5
The temperature was raised to 100°C, and the mixture was reacted for 10 hours to form a complex salt. After the reaction was completed, salting out with sodium acetate and filtration was performed, and the resulting wet cake was dried at 80°C to obtain the following structural formula. 133 parts of a 1:2 type chromium complex salt compound represented by: When the absorbance curve of a 0.003% aqueous solution of this compound was measured, it had maximum peaks at wavelengths of 470 mμ and 590 mμ, and their absorbances (-logT) were 0.50 and 0.92, respectively. Example 2 27.3 parts of J acid is dissolved in a solution of 9.2 parts of caustic soda in 200 parts of water, and 7.2 parts of acetic acid is added to form a fine dispersion. In this solution 24.5 parts of 4
After diazotized sodium -amino-1-naphthalenesulfonate (sodium naphthionate) was added at 10°C or lower, 20 parts of sodium acetate was added to perform coupling at pH 3.4. After coupling, remove insoluble matter and add 15 parts of caustic soda to the solution.
10.6 parts of soda ash were added. Add 30.5 parts of diazotized sodium picramate to this solution at 10°C.
In addition below, coupling was performed with PH9. After filtration, the wet cake was dispersed in water, 29.4 parts of chromium acetate was added, and the mixture was reacted at 100°C for 10 hours while keeping the pH around 5 to form a complex salt. By concentrating the reaction solution to dryness, the following structural formula is obtained. 60 parts of a 1:2 type chromium complex salt compound represented by the formula was obtained. When the absorption curve of a 0.003% aqueous solution of this compound was measured, it had a maximum peak at a wavelength of 590 mμ, and the absorbance (-logT) at that wavelength was 0.83. Example 3 An aluminum test piece that had been anodized using the 1:2 type chromium complex salt compound obtained in Examples 1 and 2 was colored by immersion. The coloring conditions and coloring results are summarized below.

【table】

[Table] As is clear from the table, the 1:2 type chromium complex salt compound of the present invention is sufficiently colored black even with an oxide film thickness of about 10μ, and has various properties such as light resistance, heat resistance, and weeping when washed with hot water. was also excellent. A commercially available black coloring agent, which is a 1:2 type chromium complex dye containing a sulfonic acid group, was used to color the product under the same conditions as in this example, and its various performances were examined. The heat resistance value was 2 to 2. It was low in grade 3, and it also caused weeping when washed with hot water, and was inferior in practical terms to the colored product according to the present invention.

Claims (1)

[Claims] 1. General formula {In the formula, A is a phenyl group or a naphthalene group having the following structure. [Formula] or [Formula] (Here, X ₁ , X ₂ , X ₃ , and X ₄ represent a hydrogen atom or a sulfonic acid group.) Z represents hydrogen, sodium, potassium, or ammonium ion, and n represents an integer. } A 1:2 type chromium complex salt compound represented by: 2 General formula {In the formula, A is a phenyl group or a naphthalene group having the following structure. [Formula] or [Formula] (Here, X ₁ , X ₂ , X ₃ , and X ₄ represent a hydrogen atom or a sulfonic acid group.) Z represents hydrogen, sodium, potassium, or ammonium ion, and n represents an integer. } A method for coloring aluminum, characterized by using a 1:2 type chromium complex salt compound represented by: