JPS6360119B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for coloring aluminum or aluminum alloy (hereinafter simply referred to as aluminum) in a pattern, and its purpose is to color pattern aluminum after an anodic oxide film has been formed. By interposing a unique treatment process between the two coloring processes, a new aluminum pattern is created that creates a patterned colored film on the surface of the aluminum with different tones in the corners and other parts. An object of the present invention is to provide a coloring treatment method.

Conventionally, the method of coloring the anodic oxide film of aluminum in patterns with different tones is to dip-paint aluminum that has been colored by anodizing treatment or electrolytic coloring using a thermosetting coloring paint. A method of forming a patterned colored film with different tones depending on the difference between uneven parts and flat parts (Japanese Patent Application Laid-Open No. 55-54592), or anodizing or further processing of aluminum having edges or corners with a small radius of curvature. There is a known method (Japanese Patent Application Laid-Open No. 55-50491), in which aluminum colored by electrolytic coloring or the like is painted with a thermosetting coloring paint so that the color tone differs between edges, corners, and other flat areas. However, according to these methods, it is possible to form a colored pattern, but the color tone of uneven parts, edges, or flat parts other than corner parts is colored by paint, so In some areas, the resin is worn away and the underlying color tone is exposed, so this has the drawback that it is difficult to use, especially outdoors.

The method of the present invention does not involve coloring by painting as described above, but includes a step of electrolytically coloring the anodic oxide film, followed by dip painting using a transparent synthetic resin paint, and an anodizing process to decolorize the coloring components. By combining it with, only the corners are bleached,
This is a method of recoloring the bleached anodized film on the corners to a different color tone, forming a patterned colored film that does not wear or fade on the colored parts, thereby solving the problems of the conventional method. It was resolved all at once.

In other words, when applying a single paint using the normal dipping method, the thickness of the paint film that adheres to the surface of the object to be coated depends on pure physical properties such as the physical properties of the paint or the rate at which the object is pulled up from the paint. For example, it is widely used as a vertically hanging coating method for long materials of equal cross section such as aluminum extrusion shapes because it can be controlled by various factors. That is, it is well known that the thickness of the coating film is thinner at the corners of the object than at other flat areas. This tendency becomes more pronounced as the radius of curvature of the corner portion becomes smaller, and when it is desired to increase the difference in film thickness, it is necessary to If the radius of curvature R is set to 5 mm or less, a large difference in film thickness distribution can be obtained between the corner portion and other portions.

As mentioned above, the present inventor focused on the fact that in the dip coating method, the film thickness at the corners of the object to be treated is thinner than other parts, and skillfully utilized this phenomenon to apply electrolytic coloring first. By decolorizing the corners of the anodic oxide film treated material and recoloring it after decolorization, we succeeded in obtaining a patterned colored film on the surface of aluminum that differs in color between the corner and other parts. Next, the method of pattern coloring aluminum according to the present invention will be explained in detail. In the method of the present invention, 1. An anodic oxide film is formed on aluminum, and electrolytic coloring (primary coloring) is performed in a metal salt solution. coloring).

2. Paint is applied to the colored material by dip coating, and the paint solvent on the surface of the material is evaporated.

3 Perform anodic electrolysis in an electrolyte solution to elute and decolorize the colored components in the film pores from the corner parts.

4. Perform electrolytic coloring or dyeing treatment to obtain a color tone different from the primary coloring to color only the corner portions (secondary coloring) to obtain a patterned colored film in which the color tone differs between the corner portions and other portions.

Since the processing is performed in the order of , below, the mode of implementation and matters to be kept in mind for each of these steps will be explained in detail in the order of the steps.

(1) Anodic oxide film treatment and electrolytic coloring treatment The anodic oxide film treatment and electrolytic coloring treatment (primary coloring) in this process may be carried out by the commonly used methods. Either the electrolytic coloring method (electrolytic coloring) or the Asada method (AC electrolytic coloring) may be applied.

(2) Painting treatment The painting process after the primary coloring is done by dipping, but the painting in this process has a great effect on the decolorization and secondary coloring of the corners of the treated material that will be applied in the later process. Therefore, it is necessary to carry out the process properly by paying attention to the following points.

(b) The paint used for painting the material to be treated may be any paint used for normal painting, including a solvent type using trichlene as a solvent known as the TFS painting method, as well as paints such as those commonly used for electrodeposition painting. A water-soluble type that uses water as a solvent may also be used.

(b) However, in the next decolorization process using anodic electrolysis, the coating thickness distribution that selectively electrolyzes only the corner areas and does not electrolyze areas other than the corners varies depending on the paint used during painting. Therefore, various conditions such as the paint concentration in the dipping bath and the rate of pulling up the material to be treated must be set appropriately depending on the type of paint used.

For example, when using Toa Toa Paint Co., Ltd.'s TFS paint, Toatri Paint S8001 (AL-2), which is a chlorinated solvent type paint,
It is necessary to set the coating thickness to approximately 2 to 3 μm or less in areas other than the corners of the treated material, and the solid content concentration of the paint bath is 15% at a bath temperature of 80℃.
Below, conditions are required to achieve a low film thickness of 1 m/min or less for the pulling speed of the material to be treated.

On the other hand, when using electrodeposition coating AL-200-50 manufactured by Shinto Paint Co., Ltd., which is a water-soluble type paint,
The effect of the coating film thickness is small, and it can be used sufficiently with a coating thickness of about 10 μm or less, and the solid content concentration of a suitable paint bath that takes workability into consideration is about 20%.
The effect of the pulling speed is also small.
Although the thickness of the coating film on surfaces other than the corner portions varies depending on the properties of the paint used, in the method of the present invention, conditions may be set to such an extent that the corner portions can be decolored by subsequent anodic electrolysis.

(c) It is better to evaporate the solvent from the surface of the treated material that has been pulled out of the paint bath in this way and fully fix the paint resin on the surface of the treated material before decolorizing it, as this will slow down the volatilization of the solvent. When using this type of paint, it is better to heat dry it. However, if the paint bath used is a high-temperature bath or a paint bath that easily evaporates even at room temperature, the solvent will evaporate relatively quickly when the material to be treated is pulled out of the immersion bath, so separate heat drying treatment is required. There is no need to do this. In this case, unless the solvent evaporates to some extent, decolorization due to anodization may extend to areas other than the corner areas.

(d) Also, when fixing the paint film, it is not preferable to perform heat drying treatment at high temperatures. It is best to avoid drying at high temperatures, where the paint performs best, as decolorization becomes difficult.

For example, use the electrocoating paint AL-200-50 mentioned above.
When dried at a temperature of 190°C, the corners of the treated material could not be bleached regardless of the coating thickness. For this reason, decolorization by anodic electrolytic treatment is performed by electrically destroying the coating film at the corner parts under conditions where the coating film is not completely cured, in addition to the thinness of the coating film at the corner parts. considered to be a thing.

(e) As a result of the experiment, in order to selectively decolorize only the corner portion of the material to be treated in the next anodic electrolysis, the radius of curvature of the corner portion should be approximately 5 mmR.
The following is preferable, and depending on the type of paint, the thickness of the paint film, and processing conditions such as drying, the critical radius of curvature may become even smaller. When the radius of curvature of the corner part of the material to be treated becomes large, there is little difference in the film thickness distribution between the corner part and other parts, so uneven decoloring occurs over the entire surface of the material to be treated, and it becomes difficult to decolorize the corner part. I feel relaxed.

(3) Decolorization treatment by anodic electrolysis When the electrolytically colored anodic oxide film is electrolyzed with an aqueous solution of an acid or its salt using the material to be treated as the anode, the metal or metal salt deposited in the pores of the film is removed by the electrolytic solution. It is eluted and decolorized. However, in the method of the present invention, when the material to be treated after electrolytic coloring (primary coloring) is subjected to anodic electrolysis, a coating treatment with high electrical resistance is performed in the previous step,
Since a coating film with a different thickness distribution is formed on the surface of the material to be treated between corner areas and other areas, areas where the coating film is thick other than the corner areas are not electrolyzed, and the corner areas have less paint adhesion. Since the coating film is easily destroyed electrically, only this part is electrolyzed intensively, and as a result, only the corner parts of the material to be treated are selectively decolored.

The electrolytic bath used for the anodic electrolytic treatment in this step is not specified and can be determined as appropriate from the viewpoint of economic efficiency and workability, so the electrolytic bath used for the initial anodic oxide film formation or the primary Although it is possible to use an electrolytic coloring bath that has been used for coloring, an alkaline bath easily dissolves alumite, so an acidic bath to which an acid or salt is added is preferable.

(4) Secondary coloring treatment The material to be treated whose corner portions have been decolored by the above-mentioned anodic electrolysis is then subjected to secondary coloring using a coloring method that provides a color tone different from the primary coloring. While maintaining the color tone of the primary coloring, only the corners are colored in a different tone by secondary coloring. In this case, the electrolytic coloring method may be used for the secondary coloring as in the primary coloring, or it is also possible to use a different coloring method such as a dyeing method.

(5) After forming a patterned colored film with different tones between the corner part and other parts as described above,
If the surface is again subjected to a protective coating treatment using a dipping method or a spraying method, and then a baking drying treatment, a multicolored patterned coating with excellent corrosion resistance and beautiful appearance can be obtained.

Specific examples of the pattern coloring method according to the present invention are listed below, but the present invention is not necessarily limited to these examples.

Example 1 The radius of curvature of the corner of a rectangle with one side of 40 mm
A 6063S-T5 aluminum extrusion shape with a cross section of 0.4 mmR was cut to a length of 200 mm, and after normal pretreatment, it was placed in a bath containing 150 g/l of sulfuric acid, 10 g/l of aluminum ions, and a bath temperature of 20°C. Current density inside
Perform anodizing treatment at 1.2A/ ^dm2 for 30 minutes,
An anodic oxide film of approximately 10μm is formed on the surface of the aluminum profile, and 50g/l of nickel sulfate and boric acid are applied.
40g/l, bath temperature 30℃, using nickel plate as anode
Direct current cathodic electrolysis was carried out at 0.5 A/dm ² for 30 seconds to obtain a uniform bronze coloration.

Next, the colored shape was coated with AL-200-50 from Shinto Paint Co., Ltd.
The shape was immersed in a 15% aqueous solution of resin, pulled up at a pulling speed of 0.6 m/min, and dried at a temperature of 80°C for 5 minutes. This shape was then heated using sulfuric acid.
When anodic electrolytic treatment was performed for 3 minutes at a voltage of 15 V in a bath containing 150 g/l and a bath temperature of 20°C, the bronze color was bleached at each corner, but the bronze color remained in areas other than the corner areas. It was hot.
After the decolorization treatment, the thickness of the coating film other than the corner portions was approximately 7 μm.

The shape with its corner parts bleached is made of selenium dioxide 15g/l, copper sulfate 0.6g/l, zinc sulfate 0.3g/l,
l. When DC cathode electrolysis was performed at a voltage of 13 V for 3 minutes using carbon as an anode in a bath at a bath temperature of 20°C, the corners were colored gold, and the areas other than the corners had a bronze-colored patterned colored film. Obtained.

Example 2 An extruded aluminum material (6063S-T5) having the same shape and dimensions as Example 1 was subjected to the same anodic oxidation coating treatment and electrolytic coloring treatment (primary coloring) as in Example 1.
Then, painting was applied at a pulling speed of 0.5 m/min using the TFS paint Toatri Paint S8001 (AL-2) manufactured by Toa Paint Co., Ltd. and a paint bath with a bath temperature of 80°C and a solid content concentration of 12%. After that, anodic electrolysis treatment was performed for 5 minutes at a voltage of 15 V in the electrolytic bath used to form the anodic oxide film, and only the corner portions were decolored, while the other portions remained bronze-colored.
(The thickness of the coating film other than the corner portions was approximately 1 μm.) The shape after the decolorization treatment was subjected to a cathodic electrolytic coloring treatment (secondary coloring) at a voltage of 12 V for 3 minutes in the same selenium dioxide bath as in Example 1. However, the corners were colored gold.

Example 3 A rectangle with one side of 50 mm and a corner radius of curvature
A 6063S-T5 aluminum extrusion with a cross-sectional shape of 0.5 mmR was cut into lengths of 200 mm, and after normal pretreatment, electrolysis was carried out at 150 g/l of sulfuric acid, 10 g/l of aluminum ions, and a bath temperature of 20°C. Current density in bath
1.2A/dm ² , anodizing for 30 minutes,
Further, cathodic electrolysis treatment was performed in a bath containing 50 g/l of nickel sulfate and 40 g/l of boric acid at a current density of 0.5 A/dm ² for 15 seconds to obtain a uniform colored film of light bronze color on the surface of the treated material. .

Next, this colored shape was painted at a drawing speed of 0.6 m/min in a constant temperature paint bath containing the solvent-based paint Porin AL Clear UN manufactured by Shinto Toyo Co., Ltd. diluted to a resin content of 5%. After drying at ℃ for 5 minutes, anodic electrolysis was performed at a voltage of 15 V for 5 minutes in the same sulfuric acid bath used to form the anodic oxide film, and each corner was bleached, but the others were Each side remained pale bronze in color.

The shape with this part bleached was treated with tin sulfate 5g/l.
When alternating current electrolysis was carried out for 3 minutes at a voltage of 12 V with carbon as the counter electrode in an electrolytic coloring bath containing 7 g/l of sulfuric acid and a bath temperature of 20°C, the decolored corners were colored brown.

Example 4 A 6063S-T5 aluminum extrusion having a cross-sectional shape of a rectangle with a side of 75 mm and a corner radius of curvature of 1 mmR was cut to a length of 200 mm, and after normal pretreatment, 150 g of sulfuric acid/ l, aluminum ion 10g/l, current density in an electrolytic bath with a bath temperature of 20°C
1.2A/dm ² , anodizing for 30 minutes,
Further, alternating current electrolysis was carried out for 2 minutes at a voltage of 12 V using carbon as a counter electrode in an electrolytic bath containing 5 g/l of tin sulfate and 7 g/l of sulfuric acid at a bath temperature of 20° C. to obtain a brown colored film.

Next, apply this colored shape to the coating material used in Example 1.
% aqueous solution in a normal temperature bath at a pulling speed of 1.5 m/min, and after drying for 5 minutes at a temperature of 80°C, apply a voltage of 18 V in a bath containing 100 g/l of sulfuric acid and a bath temperature of 20°C. When anodic electrolysis treatment was carried out for 3 minutes, each corner part was bleached, but the parts other than the corner parts remained brown. (Coating film thickness approx. 2μm) The shape with this corner part bleached is coated with copper sulfate.
When AC electrolytic treatment was carried out for 2 minutes at a voltage of 12 V using a copper plate as a counter electrode in an electrolytic bath containing 10 g/l of sulfuric acid and 20 g/l of sulfuric acid at a bath temperature of 20°C, the corner portions were colored reddish brown.

Example 5 An extruded aluminum material (6063S-T5) having the same shape and dimensions as Example 3 was pretreated under the same conditions as Example 1, anodized, electrolytically colored, and then coated with paint by dipping. After drying at a temperature of 60°C for 5 minutes, the corners were decolorized by anodic electrolysis treatment at a voltage of 15V for 3 minutes in a room-temperature bath containing 50g/l of oxalic acid. When immersed for 10 minutes in a dyeing bath containing iron ammonium 5g/l and a bath temperature of 50°C, a patterned colored film was formed on the surface of the treated material with yellow corners and bronze colored areas other than the corners. Obtained.

As described above, according to the method of the present invention, when applying pattern coloring to aluminum after an anodic oxide film is formed, between the two coloring steps, a simple immersion painting process and an anodizing process in an acidic solution are performed. By using a unique surface treatment method that involves both electrolytic decolorization processes, the surface of the treated material is colored in a pattern with different tones between corners and other areas, without using colored paint as in conventional methods. It is possible to obtain a film, and if this film is applied to the surface treatment of various aluminum materials, including aluminum extrusion shapes for interior fittings, it is possible to easily color multi-colored patterns using existing equipment. It has become possible to realize this method, has high productivity, has excellent corrosion resistance, and can provide a beautiful colored film with a beautiful pattern, making a great contribution to the development of this industry.

Claims (1)

[Claims] 1 After forming an anodized film on the material to be treated made of aluminum or aluminum alloy and applying primary coloring by electrolytic coloring, a transparent synthetic resin coating is applied by dipping to the surface of the material to be treated, and the corners and other parts are colored. A coating film with a different film thickness distribution is formed using the above methods, and then this treated material is subjected to anodic electrolysis in an acidic solution to selectively decolorize only the corners of the treated material, and then the color obtained by primary coloring is applied. Electrolytic coloring or secondary coloring by dyeing that produces a color tone different from the original color is applied to color only the corner parts of the treated material, and the surface of the treated material has a pattern in which the color tone differs between the corner part and other parts. A method for pattern-coloring aluminum or aluminum alloy, the method comprising obtaining a colored film.