JP2937963B2 - Colored aluminum or aluminum alloy - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a colored body of aluminum or an aluminum alloy (hereinafter referred to as "aluminum"), and more particularly, to an organic pigment or carbon black deposited deep in pores of an anodized aluminum film. And a technique for forming a robust and vivid colored oxide film.

[0002]

2. Description of the Related Art Conventionally, as a method for coloring an anodized aluminum film, an electrolytic coloring method using a bath of various metal salts, an immersion coloring method using a bath of an inorganic compound or a bath of an organic dye, and the like have been known. Many methods are known. However, in the electrolytic coloring method, it is difficult to obtain a desired color easily, the kind of color is limited, and in the coloring method, although coloring operation is possible, the obtained colored oxide film has low durability such as low durability. It is very difficult to obtain a vivid primary color colored oxide film having specifications satisfying various durability required for building exterior materials and the like.

As one measure for solving such a problem, Japanese Patent Publication No. 52-5010 and Japanese Patent Publication No.
JP-A-35177 proposes a method of anodizing aluminum in a phosphoric acid aqueous solution and coloring the aluminum by immersion or further energization in an aqueous organic pigment fine dispersion bath. Incidentally, each of the above publications describes that a pigment fine dispersion having a pigment particle size of about 1 μ (1000 nm), preferably 0.5 μ (500 nm) or less is used. Currently commercially available pigment aqueous dispersions having an average particle diameter of about 200 to 300 nm. On the other hand, the anodic oxide film to which this is applied generally has a pore diameter of about 50 nm or less. Therefore, since most of the pigment particles are larger than the pore diameter, in coloring aluminum, the pigment is colored in the form of layered adsorption and lamination on the pore openings of the anodized film and on the film surface. Therefore, there is a problem that the friction / fastness of the coloring / sealing body is low, and there is a problem that detachment of the pigment is apt to occur, and further, it is impossible to form a robust coloring body without resin coating as described in each of the above publications There is a disadvantage that.

[0004]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-mentioned problems of the prior art, and to deposit and fill a pigment deep into the pores of a porous anodic oxide film of aluminum. It is an object of the present invention to provide an aluminum colored body having a colored oxide film of a desired hue that is robust and has a vivid color without discoloration or fading, while satisfying various durability required for an exterior material and the like.

[0005]

According to the present invention, in order to achieve the above object, particles are formed from the opening of the pores of a porous anodic oxide film having a pore diameter of 50 to 200 nm formed on aluminum to the bottom of the pores. An aluminum colored body having a colored oxide film formed by depositing an organic pigment or carbon black having a diameter of 3 to 150 nm is provided. According to the present invention, such an aluminum colored body is, as a first method,
Anodizing aluminum at a high voltage in an aqueous solution of one or more acids of a mineral acid or an organic acid, and forming a porous anodic oxide film having a pore diameter larger than a normal pore diameter of about 50 nm or less on the surface of the aluminum. After formation, the organic pigment or carbon black is obtained by electrophoresis from an aqueous dispersion of an organic pigment or carbon black finely divided to a size of 3 to 150 nm in the pores of the coating. Can be Further, as a second method, aluminum is anodized in an aqueous solution of one or more acids of a mineral acid or an organic acid to form a porous anodized film on the surface of the aluminum, and then phosphoric acid, sulfuric acid, or the like. By performing a treatment of immersing in one or two or more acid aqueous solutions of oxalic acid and sulfamic acid, or a treatment of repeating the immersion and AC electrolysis in a constant cycle, the porous anodic oxide film is subjected to a pore enlargement treatment, and the pore diameter is increased. Is set to 50 to 200 nm, and 3 to 15
It can be obtained by a method in which an organic pigment or carbon black is electrophoresed and precipitated by electrophoresis from an aqueous dispersion of an organic pigment or carbon black fined to a size of 0 nm.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present inventors have found that in order to obtain a robust and vivid aluminum colored oxide film having excellent properties such as light resistance, weather resistance and heat resistance, no detachment of the pigment, and Considering that it is necessary for the pigment to be deposited as deeply as possible into the pores of the porous anodic oxide film, the pigment particles are made finer and dispersed in water, and the anodic oxide film pores that can deposit and fill the pigment are formed. Researches on the adjustment (pore diameter enlargement treatment) and the method of depositing the pigment deep into the pores have been advanced, and the colored body of the present invention has been obtained. That is, according to the present invention, an aqueous dispersion of an organic pigment or carbon black finely divided to a size of 3 to 150 nm is used, and an anodic oxide film having a pore size larger than a normal pore size is formed on the aluminum surface. And the above-mentioned organic pigment or carbon black is electrophoresed and deposited in the pores of the film by electrophoresis to obtain an aluminum-colored oxide film having the above-mentioned excellent properties.
Here, as described above, the method of forming an anodic oxide film having a pore diameter larger than the ordinary pore diameter is as follows. In the first method, aluminum is converted into one or more of a mineral acid or an organic acid.
It is performed by performing anodizing treatment at a high voltage in an aqueous solution of at least one kind of acid, while in the second method, after forming a porous anodized film on the surface of aluminum, phosphoric acid, sulfuric acid, oxalic acid, It is performed by expanding the pores of the porous anodic oxide film by a process of dipping in one or more kinds of aqueous solutions of sulfamic acid or a process of repeating dipping and alternating current electrolysis in a fixed cycle. It should be noted that the expansion of the pore diameter of the anodic oxide film should be stopped to such an extent that there is no problem in properties such as strength.

Hereinafter, the present invention will be described in detail. First, a high-grade organic pigment used as a coloring agent is a pigment which has been remarkably advanced in recent years, and is a high-grade pigment excellent in durability such as coloring property, light resistance, weather resistance, heat resistance and solvent resistance. Condensed azo-based pigments, phthalocyanine-based pigments, and perylene-based, perinone-based, quinacridone-based pigments,
Condensed polycyclic pigments such as thioindigo, dioxazine, isoindolinone, isoindoline, quinophthalone, metal complex and the like. In these pigment particles, generally, primary particles having a size of 10 to 500 nm are aggregated to form an aggregate, and it is very difficult to disperse the aggregate to the size of the original primary particles. further,
These pigments have a small surface polarity, and it is particularly difficult to disperse them in a stable state in a polar solvent such as water.
The size of the primary particles of these pigments is equal to or larger than the pore size of the aluminum anodic oxide film obtained by a usual method, or much larger. Therefore,
It is necessary to refine and disperse these pigment particles.

[0008] The pigment particles are made finer and dispersed by using an anionic polymer activator such as a formalin condensate of naphthalene sulfonic acid, polystyrene sulfonic acid salt or polyacrylic acid salt as a dispersing agent. It was found that a stable aqueous dispersion could be obtained by dispersing in water. Further, if the pigment is previously subjected to a surface treatment such as a plasma treatment before being dispersed by a sand mill, a more excellent aqueous dispersion can be obtained. Furthermore, since most of these higher organic pigments dissolve in concentrated sulfuric acid, these pigments are dissolved in concentrated sulfuric acid once, added to water, and precipitated as finer pigment particles. Can also be used together. By such a method, the particle diameter is 3 to 15
A stable aqueous dispersion of the pigment of 0 nm, preferably 3 to 100 nm, is prepared.

Next, as an aluminum anodic oxide film having a pore diameter capable of depositing a pigment, 50 to 200 nm,
Preferably, it is necessary to have an anodized film having a pore diameter of 50 to 150 nm. As the anodizing bath, a mineral acid or an organic acid such as sulfuric acid, phosphoric acid, oxalic acid, malonic acid, one or two or more acid aqueous solutions of maleic acid can be used, and preferably an oxalic acid aqueous solution is mainly used. Bath is desirable. In the first method of the present invention, aluminum is anodized at a high voltage of about 130 V or more in an aqueous solution of one or more of the above-mentioned mineral acids or organic acids, and a normal pore size is formed on the surface of the aluminum. Form a larger porous anodic oxide film. As described above, since the pore diameter of the anodic oxide film obtained by the ordinary anodic oxidation treatment is 50 nm or less, the deposition of the pigment in the pores depends on the average particle diameter of the pigment. Although it is generally difficult, when anodizing is generally performed at a high voltage of 150 to 200 V DC, an anodic oxide film having a pore diameter of 120 nm or more is obtained. Can be deposited. That is, if the voltage of the anodic oxidation treatment is lower than the above-mentioned voltage, it is difficult to obtain pores large enough for the deposition of the pigment, which is not preferable. It is not preferable because it has an adverse effect.

In the second method of the present invention, aluminum is first anodized in an aqueous solution of one or more of the above-mentioned mineral acids or organic acids to form a porous anodized film on the surface of the aluminum. . As the electrolysis conditions, 35 V or more,
An anodic oxide film having a large cell size and a large pore diameter is obtained by high-voltage electrolysis of preferably 50 to 160 V. Then
The film pores are expanded by immersing in one or more aqueous acid solutions of phosphoric acid, sulfuric acid, oxalic acid, and sulfamic acid, preferably in an aqueous solution of 3 to 10 W / V% phosphoric acid. The anodic oxide film suitable for coloring of the present invention is obtained by adjusting the pore size to 200 nm, preferably 50 nm to 150 nm. Further, in order to shorten the time required for the process of expanding the pores of the film, the immersion and alternating current electrolysis are alternately repeated at short intervals in an aqueous solution of phosphoric acid of 3 to 10 W / V%.
The process of expanding the film pores can be performed in a relatively short time.

In the coloring treatment, the dispersed pigment is induced and deposited to the deep part of the pores of the film by electrophoresis in an aqueous dispersion of a high-quality organic pigment or carbon black using the aluminum material having the anodic oxide film as an anode. And a vivid colored film can be obtained. As the electrophoresis method, a DC voltage scanning method in which a DC voltage is scanned from a low voltage to a high voltage at a constant step-up speed until a desired color is obtained, and a DC voltage scanning method in which the time until the desired color is obtained at a constant voltage is performed. A coloring process is performed by a voltage method or the like. The aluminum colored body thus obtained can be subjected to a sealing treatment or a clear coating, if necessary.

[0012]

The coloring pigment in the oxide film colored by the method of the present invention is deposited on the deepest portion of the oxide film pores, as can be seen from the carbon wire obtained by the line analysis by EPMA shown in FIG. I have. For this reason, the pigment of the colored body does not easily come off due to friction or the like, and it is possible to obtain a strong and durable bright colored film. In addition, by selecting a pigment, it can be colored in various desired colors such as red, black, and blue, and can sufficiently meet the needs for multicolor aluminum. Conventionally, a method of coloring aluminum using a pigment has not been put to practical use, but the present invention makes it possible and can be said to be of great value in practical use.

[0013]

The present invention will be specifically described below with reference to examples. Example 1 Industrial pure aluminum plate (JIS A1050P-H2)
4, 50 × 20 mm) was pretreated according to a conventional method, and then subjected to constant voltage electrolysis at 30 ° C. in a 5% oxalic acid bath at 160 V DC for 5 minutes to form an anodized film having a film thickness of 10 μm. Then, using the aluminum plate as an anode, 2
DC 60 in a 10% carbon black aqueous dispersion bath at 5 ° C.
The electrophoresis treatment was carried out for 1 minute at V to produce an aluminum anodic oxide film that was brightly colored black. The same size carbon electrode was used as the cathode. The obtained colored oxide film was robust and excellent in durability. The aqueous carbon black dispersion was obtained by dispersing a 1 L solution of water in which 5 g of a solid content was added to 100 g of carbon black using sodium polyacrylate as a dispersant for 5 hours with a sand mill, and the average particle diameter was 60 nm. is there.

Example 2 After pretreatment of the industrial pure aluminum plate according to a conventional method, constant voltage electrolysis was performed for 6 minutes at 20 ° C. in a 0.3% oxalic acid bath at DC 150 V for anodizing with a film thickness of 10 μm. A film was formed. Next, this aluminum plate was immersed in a 5% phosphoric acid solution for 0 to 300 minutes to perform a process of enlarging the film pore diameter. Thereafter, the aluminum plate was used as an anode to perform an electrophoresis treatment in the aqueous 10% carbon black dispersion bath at 25 ° C. used in Example 1 to form an aluminum anodic oxide film colored black. The same size carbon electrode was used as the cathode. Table 1 shows the results. In addition, FIG. 1 shows a line analysis diagram of carbon in the colored oxide film by EPMA when the above-mentioned coating pore diameter dip treatment was performed for 100 minutes.

[0015]

[Table 1]

Example 3 After pretreatment of an aluminum alloy 63S plate in accordance with a conventional method, constant voltage electrolysis was performed in a 0.3% oxalic acid bath at 20 ° C. for 6 minutes at 150 V DC to obtain an anodic oxide film having a film thickness of 10 μm. Is formed and then placed in a 5% phosphoric acid aqueous solution at 30 ° C.
The film was immersed for 20 minutes to perform a process of enlarging the film pore diameter. Next, this was placed in a 1 L bath of an aqueous dispersion of 10% dioxazine violet at 25 ° C., using the aluminum plate as an anode, for 8 hours.
Electrophoresis was performed at a constant voltage of 0 V to obtain a purple-colored film. The aqueous dispersion of dioxazine violet is obtained by adding a 1% aqueous solution of sodium polystyrene sulfonate to 100 g of dioxazine violet to make a total volume of 1 L, and dispersing the mixture for 10 hours using a sand mill. Is 55 nm.

Example 4 After pretreatment of an aluminum alloy 63S plate according to a conventional method, formation of an anodic oxide film and enlargement of the hole diameter were performed in the same manner as in Example 2. Next, in an aqueous dispersion of 50 g / L copper phthalocyanine blue at 30 ° C., the aluminum plate was used as an anode and subjected to electrophoresis at a voltage of DC 80 V to obtain an anodized film colored blue. The cathode was a carbon electrode, and the electrophoresis time was 2 minutes. The aqueous dispersion of the pigment was prepared by dissolving 50 g of copper phthalocyanine blue in 600 mL of 98% sulfuric acid, and stirring it with 0.5%.
Was added to 5 L of aqueous sodium polyacrylate solution to precipitate phthalocyanine particles, washed with water until the sulfate group disappeared, adjusted to pH 9 with sodium hydroxide, and added with 0.5% aqueous sodium acrylate solution so that the total amount became 1 L. Then, the mixture is dispersed in a sand mill to obtain a particle diameter of 50.
An aqueous dispersion of copper phthalocyanine blue having a thickness of nm was obtained.

Example 5 An aluminum oxide 63S plate was pretreated according to a conventional method, and then subjected to constant voltage electrolysis in a 0.3% oxalic acid bath at 20 ° C. for 6 minutes at 150 V DC to form an anodic oxide film having a film thickness of 10 μm. Is formed, and A is added in an aqueous 8% phosphoric acid solution at 25 ° C.
A repetitive treatment of C8V electrolysis for 1 minute and AC0V for 2 minutes was performed for 30 minutes to perform a process of enlarging film pores. Next, in an aqueous dispersion of 50 g / L copper phthalocyanine blue at 30 ° C. prepared by the method of Example 4, the aluminum plate was used as an anode, and the cathode was made of carbon, followed by electrophoresis at a constant voltage of 80 V DC for 2 minutes. Thus, a blue-colored anodized film was obtained.

Example 6 A red anodic oxide film was obtained by treating an aluminum alloy 63S plate in exactly the same manner as in Example 4 except that 50 g / L of quinacridone red was used instead of the copper phthalocyanine blue of Example 4. The average particle size of the aqueous quinacridone red dispersion was 70 nm.

Example 7 An aluminum alloy 63S plate was used instead of copper phthalocyanine blue of Example 4, and a highly chlorinated copper phthalocyanine green was used. In place of sodium polyacrylate as a dispersant, sodium naphthalene sulfonate formalin condensate was used. In the same manner as in Example 4, a green anodic oxide film was obtained.

[Brief description of the drawings]

FIG. 1 is a line analysis diagram of carbon in a colored oxide film obtained in Example 2 by EPMA.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) C25D 11/20-11/22 302

Claims (1)

(57) [Claims] 1. A particle diameter of 3 to 150 nm from the opening to the bottom of a pore of a porous anodic oxide film having a pore diameter of 50 to 200 nm formed on aluminum or an aluminum alloy.
Aluminum or aluminum alloy having a colored oxide film formed by depositing an organic pigment or carbon black.