JPH08246191A - Formation of blue-gray colored composite film of aluminum material and aluminum alloy material - Google Patents

Abstract

PURPOSE: To produce a blue-gray colored film by coloring an anodically oxidized film into a black and thereafter forming a penetratable white film by electrolyzing treatment. CONSTITUTION: The surface of an aluminum or aluminum alloy material 1 is subjected to anodic oxidation treatment to form an oxidize film 10, and after that, it is colored into black by electrolytic pigmenting treatment. Next, it is subjected to electrolytic treatment in a soln. of electrodeposition coating material contg. 0.01 to 0.5wt.% white pigment 31 having 0.3 to 10μm grain size to form a penetratable white coating film 30 on a black anodically oxidized film 10. As the black pigmenting method for the anodically oxidized film 10, an electrolytic pigmenting method in which electrolytic treatment is executed in an electrolytic pigmenting bath contg. the metallic salt of Ni, Co, Sn, Cu or the like to largely precipitate the metallic salt in the fine pores 11 of the anodically oxidized film 10 is preferable from the points of the cost, quality and productivity. Furthermore, as the white coating film 30, white pigment such as zinc oxide and white ceramics such as alumina, zirconia and baron nitride are preferably used in the kneading with varnishes and surfactants.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite film forming method for forming a bluish gray composite film on an aluminum material and an aluminum alloy material. Especially, it is used for the production of building materials and exterior products.

[0002]

2. Description of the Related Art Building materials such as curtain walls, interior and exterior materials, and exterior products such as gates and fences produced from aluminum materials or aluminum alloy materials (hereinafter, abbreviated as "aluminum materials") With the widespread spread of, the diversification of the color tone is strongly requested.

As a method of coloring an aluminum material, for example, an alloy coloring method, an electrolytic coloring method and the like are known, and the color tone thereof can be selectively colored in various chromatic colors. However, individualization and diversification do not cease, so demand for achromatic colors has increased.

As a coloring method with an achromatic color as a target color,
Alloy coloring method (JP-A-2-254129), secondary electrolysis method (JP-A-61-143593), coating method, anodizing method utilizing current recovery phenomenon (JP-A-1-212796).
No.), a method for obtaining a composite film by performing electrodeposition coating containing a chromatic pigment on a bronze-colored anodic oxide film (JP-A-3-18).
No. 3798) and the like are known.

[0005] Here, when the practical productivity such as the thickness control of the anodic oxide film and the bath stability is compared and weighed, the above-mentioned JP-A-3-
It is presumed that the composite film forming method disclosed in 183798 is superior. In this method, an aluminum material is subjected to anodization treatment, then electrolytically colored to a bronze-based color, and then a gray tone composite film is obtained by electrodeposition coating containing a chromatic color pigment.

Among the gray tones, as described in the table in the lower right column on page 7 of the above-mentioned publication, light gray, gray, dark gray, dark grayish,
Includes grayish. However, since the electrolytically colored film is light bronze, bronze, or dark bronze, it is reddish gray or yellowish gray. That is, C
According to the IE-1976 (L ^* , a ^* , b ^* ) color space color system, both indices a ^* and b ^* are on the plus (+) side, and their absolute values are achromatic values of "1 or less". It is a value far exceeding "(for example," 4.6 "). In other words, this is a method of obtaining a gray chromatic color in which reddishness or yellowishness is relatively strongly felt.

[0007] Incidentally, in [Comparative Example 2] described on page 7, upper right column, line 13 to left lower column, line 4 of the same publication, a bronze-colored electrolytically colored film is formed on an aluminum material, It is specified that when a coating film was formed in a blue pigment-containing electrodeposition coating solution, a blue-based composite film was obtained, and a gray-based composite film could not be obtained. The use of blue pigment seems to be a natural result. This is because, for example, if a red pigment is used, the color becomes red.

[0008]

As described above, even if any of the above-mentioned conventional methods can obtain a gray chromatic color, an achromatic color whose absolute value of the indices a ^* and b ^* is "1" or less ( Gray) cannot be obtained.

Here, a third electrolytic coloring method (Japanese Patent Laid-Open No. 53-2 / 53) is used.
2834), it was confirmed that a bluish gray color was obtained. In addition, with several samples with different lightness (L ^* ) of this blue-based gray color and the achromatic color (gray) applied to the aluminum material by the spray coating method, the average engineer and general consumer in the building industry According to the result of marketing to the target, the bluish-gray color, which is bluish, is overwhelmingly favored than the completely achromatic color. Further, in comparison with the conventional gray-based chromatic colors other than the blue-based chromatic colors according to the above-mentioned publication, the novelty and the superiority or hobby from the viewpoint of mass color or stable color were supported.

However, since the above-mentioned tertiary electrolytic coloring method utilizes the interference effect of light, the color tone changes due to a slight structural change relating to the thickness, quality, etc. of the anodic oxide film, so it is very unstable and reproducible. The problem is that the yield is poor because of low cost, resulting in high cost and slow production.

The present invention has been made in view of the above circumstances, and an object thereof is an aluminum material and an aluminum alloy capable of stably forming a blue-gray composite coating with high reproducibility and at low cost. To provide a method for forming a blue-based gray color composite film of a material.

[0012]

With the formation of an achromatic composite film in mind, it is conceptually extremely difficult to achromaticize using a bronze chromatic color as a base. Here, since the achromatic color has only lightness, the applicant has conducted a test study on a combination of black and white based on the general color tone principle.

That is, the aluminum material 1 shown in FIG. 1 is anodized to form an anodized film 10, and the film 1
0 is colored black. Here, the black range is CIE-
The value of L ^{* in} the 1976 (L ^* , a ^* , b ^* ) color space color system is 2
It is preferably 6 or less. This is based on the relationship with the white coating film 30 described later.
As a coloring method, electrolytic treatment is performed in an electrolytic coloring bath containing a metal salt such as Ni, Co, Sn, or Cu, and a large amount of the metal salt 20 is deposited in the fine pores 11 of the anodized film 10 to produce a black color. I tried an electrolytic coloring method and a dyeing method of coloring black with a black dye, but the former was selected as an advantage in terms of cost, quality and production.

On the basis of this selection, the validity of the anodizing treatment was examined. As a result, each anodizing was carried out by a conventional method in a mineral acid such as sulfuric acid and phosphoric acid, an organic acid such as oxalic acid and sulfosalicylic acid, or an aqueous solution of these mixed acids. When the treatment was carried out, there was no difference in carrying out the subsequent electrolytic coloring step. However, it was confirmed that the thickness of the anodic oxide coating 10 is preferably 6 to 15 μm for black electrolytic coloring.

Next, as a method for applying the white paint to the black anodic oxide coating (10, 20), there are electrostatic coating, dip coating and electrodeposition coating. In this case as well, cost, quality,
Electro-deposition coating was selected as an advantage due to the reality of productivity.

As the white pigment constituting the electrodeposition liquid composition for electrodeposition coating, white inorganic pigments such as titanium white, lead white and zinc white, and white ceramics such as alumina, zirconia and boron nitride are used. To use. The white pigment 31 is preferably kneaded with a varnish and a surfactant in order to improve dispersibility in the electrodeposition bath. The concentration of the white pigment 31 is 0.
If it is 01 to 0.5 w% and is less than this range, the white coating film 30 cannot be obtained with a practical coating thickness, and if it is more than this range, a observable white coating film 30 cannot be obtained. Preferably, 0.
The range of 05-0.3w% is good.

Further, the particle size of the white pigment 31 is 0.5.
10 μm is suitable. If the particle size is too small, the coating film 3
Not only is the whitening of 0 inferior and the white pigment 31 of a specified concentration or more is required, but also the dispersibility of the white pigment is deteriorated and the corrosion resistance of the coating film is deteriorated. On the contrary, when the particle size is too large, sedimentation of the white pigment is accelerated, which causes a problem in bath stability.
The resin component is made of acrylic resin or fluororesin and melamine resin, and the heating residue is adjusted to a range of 5 to 15 w% before use.

The electrodeposition coating treatment conditions are a bath temperature of 15 to 25 ° C.
A DC voltage of 100 to 300 V is applied with the black anodic oxide film formed aluminum as an anode. Thereby, the white coating film 30 having a coating film thickness of 6 to 30 μm and capable of seeing through the underlying layer can be formed. A thick coating film gives a gray color having a high lightness, and a thin coating film gives a gray color having a low lightness. In this way, the brightness of the bluish gray color can be controlled by adjusting the thickness of the coating film. It is also possible to adjust the brightness by adjusting the density of the white pigment 31.

Black anodized film (10, 20)
It is preferable to perform washing (washing with hot water) in warm water of about 70 ° C. to remove foreign ions before electrodeposition coating. Further, after the electrodeposition coating treatment, it is preferable to remove the undeposited white pigment 31 and the resin component by a water washing treatment. Finally, this is 150-25
The coating film is baked and dried in an atmosphere of 0 ° C.

By the combination of the anodizing treatment, the black electrolytic coloring treatment and the white electrodeposition coating treatment using the white pigment 31, the lightness index L ^* is, for example, 30 to 42 and the red to green index a ^* tends to be green. (For example, -0.5 to -1.0) and yellow to
It is possible to form a blue-based gray-colored composite film having a blue index b ^* that tends to be blue (for example, -1.2 to -3.5). That is, it is possible to obtain a bluish gray color that is as close as possible to an achromatic color. The gloss of the composite coating can also be adjusted by changing the resin component of the electrodeposition paint to a high gloss type or a low gloss type.

That is, according to the method for forming a blue-based gray color composite coating film of an aluminum material and an aluminum alloy material according to the present invention, the aluminum material or the aluminum alloy material is subjected to anodizing treatment to form an anodized coating, and then electrolytically colored. The anodic oxide coating is treated to give a black color, and then blackened by electrolytic treatment in an electrodeposition coating solution having a particle size of 0.5 to 10 μm and containing 0.01 to 0.5 w% of a white pigment. A white coating film is formed on the anodic acid coating so that the black anodic oxide coating can be seen through.

[0022]

In the case of the present invention having the above construction, the aluminum material is anodized to form a positive oxide film. Next, electrolytic coloring treatment is performed to color the anodized film black. Further, on the black anodic oxide film, the particle size is 0.5 to 10
Electrolytic treatment is performed in an electrodeposition coating solution containing 0.01 to 0.5 w% of a white pigment in μm to form a transparent white coating film on the black anodized film.

In the composite film thus obtained, part of the daylight A shown in FIG. 1 is reflected on the surface of the outermost white coating film 30. The amount of reflected light B1 determines the gloss. Then
The other part is dispersed in the coating film and reflected by the white pigment 31 (B
2) and a white color appearance is exhibited. Further, the remaining part is a metal 2 deposited in the fine pores 11 of the anodic oxide film 10.
It is reflected (B3) on the surface of No. 0 and appears black in appearance. There is also a small amount of reflected light (B4) from the aluminum material 1.

Thus, if the reflected light from the composite film reflects the entire spectrum of the daylight light A, it becomes an achromatic gray color, but the relationship between the particle size of the white pigment 31 and the spectrum of the daylight low wavelength part is mainly. Therefore, it becomes a gray color with a slight bluish tint.

The brightness of the bluish gray color is determined by the ratio of the amount of reflected light between the black coating (10, 20) and the white coating 30. Therefore, the white pigment 31 in the white coating film 30
When the absolute amount of is large, the amount of reflected light from the black film (10, 20) is small, and the brightness is high.

[0026]

Embodiments of the present invention will be described below. (First Example) After performing an ordinary pretreatment on an aluminum material, that is, an aluminum extruded shape material (A6063), 150 g /
20 ℃ in 1-H ₂ SO ₄ aqueous solution, current density 120A /
The m ² was anodized for 30 minutes to form a 10 μm anodized film. Next, stannous sulfate 10 g /
An alternating current of 15 V was applied in an electrolytic coloring solution containing 1 and electrolytic treatment was performed for 10 minutes to obtain a black anodized film having an L ^* value of "26" or less. Next, a direct current of 180 V was applied in an electrodeposition coating liquid containing 0.1% by weight of titanium white having a resin solid content of 10% by weight and a particle size of 5 μm to perform an electrolytic treatment for 2 minutes.
A μm electrodeposition coating film was formed. Finally, it was baked and dried at 180 ° C. for 30 minutes to obtain a bluish gray-colored and glossy composite film.

A colorimeter (CR200 manufactured by Minolta)
The following results were obtained by measuring the color with a (type). L ^* = 35.2 a ^* = − 0.9 b ^* = − 1.7

Here, the red-green index a ^* is the green tendency "-".
0.9 "and within the achromatic color (" 1 or less ") range, and the yellow-blue index b ^* is" -1.7 "which slightly deviates from the achromatic color (" 1 or less ") range. It is understood to be an excellent bluish gray color that is as close to achromatic as possible.

Further, in comparison with the gray bronze color shown in the following (Comparative Example 2), it has a new color tone, is full of a sense of mass, and has a low color, and also has excellent corrosion resistance and weather resistance as a composite film. I was able to confirm that Furthermore, 5
Even if repeated 0 times, the same bluish gray color could be obtained with high stability and high reproducibility in each time.

(Second Embodiment) Aluminum plate (A110)
0) was subjected to normal pretreatment, and then 150 g / 1-H ₂ S
Anodizing treatment was performed in an O ₄ aqueous solution at 20 ° C. at a current density of 120 A / m ² for 45 minutes to form a 15 μm thick anodic oxide film as compared with the case of the first embodiment. Next, in an electrolytic coloring solution containing 100 g / 1 of nickel sulfate, alternating current 1
6 V was applied and electrolytic treatment was performed for 10 minutes to obtain a black anodized film having an L ^* value of "26" or less. Next, microgel type resin solid content 10w%, particle size 5μm
0.2w% of 1-10μm alumina with maximum distribution in
A direct current of 180 V was applied in the contained electrodeposition coating liquid to carry out electrolytic treatment for 2 minutes to form a 15 μm electrodeposition coating film. Finally, it was baked and dried at 180 ° C. for 30 minutes to obtain a bluish gray gray low gloss composite film.

This was color-measured with the same colorimeter and the following results were obtained. L ^* = 31.2, a ^* =-0.5 b ^* =-2.7

Compared with the case of the first embodiment, by increasing the thickness of the anodized film (15 μm) and increasing the content of white alumina in the electrodeposition coating solution to 0.2 w%, the yellow to The blue index b ^* was "-2.7", and the blueness could be further increased.

(Third Example) Aluminum extruded profile (A
6063) after the usual pretreatment, 150g / 1-
20 ℃ in H ₂ SO ₄ aqueous solution, current density 120A / m ²
Then, an anodic oxidation treatment was performed for 30 minutes to form a 10 μm anodic oxide film. Next, an alternating current of 15 V was applied in an electrolytic coloring solution containing stannous sulfate of 10 g / 1 to perform electrolytic treatment for 10 minutes to obtain a black anodized film similar to that in the first example. Next, resin solid content 10w%, particle size 5μm
DC in an electrodeposition coating solution containing 0.1% by weight of titanium white
80 V was applied and electrolysis was performed for 3 minutes to form an electrodeposition coating film of 20 μm thicker than in the first embodiment. Finally, it was baked and dried at 180 ° C. for 30 minutes to obtain a bluish gray-colored and glossy composite film.

This was color-measured with the same colorimeter and the following results were obtained. L ^* = 41.9, a ^* =-1.0 b ^* =-3.5

As compared with the case of the first embodiment, by increasing the thickness of the white coating film, the index b ^* becomes "-3.
It was possible to obtain a gray color in which the bluish color was further emphasized, which is 5.

(Comparative Example 1) Aluminum extruded profile (A6
063) after the usual pretreatment,
Anodizing treatment was performed in a ₂ SO ₄ aqueous solution at 20 ° C. and a current density of 120 A / m ² for 30 minutes to form a 10 μm anodic oxide film. Next, 100 g / 1 of nickel sulfate
An alternating current of 16 V was applied in the contained electrolytic coloring solution to perform electrolytic treatment for 10 minutes to obtain a black anodized film having an L ^* value of "26" or less. Next, a direct current of 180 V was applied in an electrodeposition coating solution containing 10% by weight of resin solids and 0.5% by weight of alumina having a particle size of 0.05 μm, and electrolysis treatment was performed for 3 minutes to obtain an electrodeposition coating film of 20 μm. Was formed. Finally, 180 ℃
After baking and drying for 30 minutes, a composite film having a gloss very similar to black rather than gray was obtained.

The color was measured with the same colorimeter and the following results were obtained. L ^* = 27.1, a ^* = 0.05 b ^* = − 0.29

Therefore, the white pigment (alumina) is added to the second
As in the case of the examples, even if the electrodeposition coating is carried out at the same voltage and for the same time in the electrodeposition coating liquid containing 0.5% by weight, the particle diameter is 0.5.
When the thickness is 0.05 μm or less, the white coating film does not have a substantial effect. That is, it can be seen that the color of the black anodic oxide film itself is the achromatic color but the bluish gray color cannot be obtained.

(Comparative Example 2) Aluminum extruded profile (A6
063) after the usual pretreatment,
Anodizing treatment was performed in a ₂ SO ₄ aqueous solution at 20 ° C. and a current density of 120 A / m ² for 30 minutes to form an anodized film having the same thickness of 10 μm as in the first embodiment. Next, in an electrolytic coloring solution containing 100 g / 1 of nickel sulfate, alternating current 15
V was applied and electrolysis was carried out for 2 minutes to obtain a bronze anodized film. Next, as in the case of the first embodiment, 0.1% of titanium white having a resin solid content of 10 w% and a particle diameter of 5 μm is added.
A direct current of 180 V was applied in an electrodeposition coating liquid containing w% and electrolysis was performed for 2 minutes to form a 15 μm electrodeposition coating film. Finally, it was baked and dried at 180 ° C. for 30 minutes to obtain a gray bronze-colored glossy composite film.

This was color-measured with the same colorimeter and the following results were obtained. L ^* = 48.7, a ^* = 1.9 b ^* = 4.6

Comparing this with the case of the first embodiment, an electrodeposition coating composition containing 0.1% by weight of titanium white having a particle size of 5 μm in a bronze-colored anodized film having an L ^* value of more than “27”. Electrolyzed for the same 2 minutes in the same, and the same 15
Even if an electrodeposition coating film of μm is formed, the color influence of the base (a bronze color anodized film) is strong and the index a ^* tends to be red.
In the case of 9 ", the index b ^* is" 4.6 "which tends to be yellow, so that only a light gray bronze color is obtained.

[0042]

According to the present invention, an aluminum material or an aluminum alloy material is anodized to form an anodized film, and then electrolytically colored to give the anodized film a black color. Particle size is 0.5-10 μm
Composite film for forming a white coating film on the black anodic acid coating through which electrolysis is performed in an electrodeposition coating solution containing 0.01 to 0.5 w% of a white pigment. Since it is a forming method, it is possible to form a blue-gray composite film close to an achromatic color with high reproducibility and stably. Therefore, it is possible to provide a blue-colored gray building material, an exterior product, or the like, which has a new color and is rich in mass and has excellent corrosion resistance and weather resistance, at low cost.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a method for forming a composite film of the present invention.

[Explanation of symbols]

 1 Aluminum Material 10 Anodized Film (Black Anodized Film) 11 Micropores 20 Precipitated Metal (Black Anodized Film) 30 White Coating 31 White Pigment

Claims (1)

[Claims] 1. An aluminum material or an aluminum alloy material is anodized to form an anodized film, and then electrolytically colored to color the anodized film black, after which the particle size is 0.5. 0.01 to 10 μm
Aluminum, which is characterized in that it is subjected to an electrolytic treatment in an electrodeposition coating solution containing 0.5 w% of a white pigment to form a white coating film on the black anodic acid coating through which the black anodic oxide coating can be seen. Method for forming blue-based gray composite film of aluminum and aluminum alloy materials.