JPS642677B2 - - 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. , is a novel method that uses a series of treatment steps including two coloring treatments before and after to obtain a highly durable and beautiful patterned colored film on the surface of the treated material, with different color tones between corners and other areas. The objective is to establish a method for coloring patterns.

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 unevenness and flatness of the surface (Japanese Patent Application Laid-Open No. 55-54592), or anodizing or anodizing aluminum having edges or corners with a small radius of curvature. Furthermore, there is a known method (Japanese Unexamined Patent Publication No. 55-50491) in which aluminum colored by electrolytic coloring or the like is painted with a thermosetting colored paint to make the color tone different between edges, corners, and other flat parts. However, according to these methods, it is possible to form a patterned colored film, but the color tone of flat areas other than uneven areas, edges, or corners is colored by paint, so it is difficult to use paint. Since the resin is worn away and the color tone of the base is exposed, this has the drawback that it is difficult to use it in practice, especially outdoors.

The pattern coloring method of the present invention was developed to solve the problems of the conventional method, and includes:
After forming an anodic oxide film on the aluminum material to be treated and applying primary coloring using electrolytic coloring, dip coating is applied to the surface of the material to be treated to create a coating with different film thickness distribution between corners and other parts. forming a film,
Next, if necessary, the material to be treated is anodically electrolyzed in an acidic aqueous solution to selectively decolorize only the corners of the material, and then secondary coloring by electrolytic coloring or dyeing is applied to the material to be treated. After coloring only the corners of the material to obtain a patterned colored film with different tones between the corners and other parts on the surface of the treated material,
Furthermore, the method is characterized in that the material to be treated is immersed in a bath containing an organic solvent to dissolve the coating film on the surface and then coated again.

Next, the method of coloring aluminum in a pattern according to the present invention will be explained specifically and in detail. In the method of the present invention, 1. An anodic oxide film is formed on the surface of aluminum, and electrolytic coloring (primary coloring) is performed in a metal salt solution. Do the following.

2. After applying the paint to the colored treated material using the dip coating method, the solvent of the paint is evaporated,
To form a coating film on the surface of a material to be treated, which has a different thickness distribution between corner parts and other parts.

3. If necessary, the material to be treated is subjected to anodic electrolysis in an acidic aqueous solution to elute and decolorize the colored components in the film pores from the corner portions.

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.

5. The material to be treated is immersed in a bath containing an organic solvent to dissolve the coating film on the surface and repainted.

Since the processes are 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 After the primary coloring, coating is performed by dipping, but 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 is Since the thickness can be controlled by pure physical factors such as the physical properties of the paint or the rate at which the object to be coated is pulled up from the paint, it is widely used as a vertically suspended coating method for long materials of equal cross section, such as extruded aluminum shapes. It is well known that the state of adhesion of the paint to the surface of the object during painting, that is, the thickness of the paint film, is thinner at the corners of the object than on other flat areas. ing. This tendency becomes more pronounced as the radius of curvature of the corner portion becomes smaller.
When you want to increase the difference in film thickness, change the type of paint,
Although it varies somewhat depending on conditions such as the thickness of the coating film, in the normal case, if the radius of curvature R of the corner portion is set to 5 mm or less, a large film thickness distribution can be obtained between the corner portion and other portions.

The painting process in this process is carried out by skillfully utilizing the phenomenon described above, and when it is carried out, it has a great influence on the subsequent process, so please pay attention to the following points and make sure to do it properly. It is necessary to do so.

(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 and secondary coloring process, the coating film distribution in order to selectively electrolyze or dye only the corner parts so that areas other than the corner parts are not colored is as follows. Since this varies depending on the paint used during painting, 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, approximately 2 to
It is necessary to set the coating thickness to 3 μm or less, and suitable conditions are such that the bath temperature is 80°C, the solid content concentration of the paint bath is 15% or less, and the pulling speed of the material to be treated is 1 m/min or less.

On the other hand, when using electrocoating paint AL-200-50 manufactured by Shinto Toyo Co., Ltd., which is a water-soluble type paint, the effect of coating film thickness is small, and it can be used satisfactorily with a coating thickness of about 10 μm or less. The solids concentration of a suitable paint bath, taking into account workability, is approximately 20% or less, the pulling speed has little effect, and the thickness of the coating on surfaces other than the corner parts depends on the properties of the paint used. Although different, in the method of the present invention, conditions may be set to the extent that the subsequent electrolytic treatment and dyeing treatment can be performed.

(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 decoloring or coloring. When using a type of paint that evaporates slowly, it is better to dry it by heating. 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.

(d) Also, when fixing the paint film, it is not preferable to carry out the heat drying treatment at high temperatures.If the paint is cured more than necessary by high temperature drying, it may be necessary to perform bleaching or coloring by electrolysis in the next process or the final process. It is best to avoid drying at high temperatures, where the paint exhibits its original performance, as this will make it difficult to dissolve the paint film.

For example, the electrodeposition paint AL-200-50 mentioned earlier
When dried at a temperature of 190°C, the corners of the treated material cannot be electrolytically treated for bleaching or coloring, regardless of the thickness of the coating, and it is also difficult to dissolve and repaint the coating in the final process. Summer. For this reason, the electrolytic treatment for decolorizing, coloring, and dissolving the paint film is not only because the paint film is thin at the corner parts, but also because the paint film at the corner parts is not electrically cured under conditions where the paint film is not fully cured. It is thought that this is done by destroying it.

(e) As a result of the experiment, in order to selectively bleach or color only the corners of the material to be treated in the next step,
The radius of curvature of the corner portion is preferably about 5 mmR or less, and the critical radius of curvature may become even smaller depending on the type of paint, the thickness of the paint film, and processing conditions such as drying. When the radius of curvature of the corner part of the material to be treated increases, the difference in film thickness distribution between the corner part and other parts is small, so uneven bleaching or coloring occurs on the entire surface of the material to be treated, or decolorization and uneven coloring of the corner part occur. Coloring may become difficult.

(F) If the coating surface obtained by dip coating in this process goes through the subsequent decolorization process or second coloring process, the coating surface may lack smoothness or become uneven in gloss, and this may be left as is. It is not necessarily necessary to use a transparent coating because it will be melted and repainted in the final step without leaving it as a protective coating.

(3) Decolorization treatment by anodic electrolysis When the electrolytically colored anodic oxide film is electrolyzed in 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 electrolyzed. It is eluted into the liquid 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, and the corner portions are painted on the surface of the material to be treated. Since the coating film is formed with a different thickness distribution between the corners and the other parts, the thicker parts of the coating film other than the corner parts are not electrolyzed, and the coating film in the corner parts where there is less paint adhesion is electrically destroyed. Therefore, only this part is electrolyzed intensively, and as a result, only the corner parts of the material to be treated are selectively decolored.

In the case of the present invention, this decolorization process is a case in which the material to be treated is subjected to the above-mentioned anodic oxidation treatment, primary coloring treatment, and dip coating treatment, then the decolorization treatment of this step is performed, and then the secondary coloring treatment is performed. Similarly, after anodizing treatment, primary coloring treatment, and dip painting treatment, there are cases where secondary coloring treatment is directly applied without performing the decolorization treatment of this step, and when there is a decolorization treatment step,
The corners of the material to be treated are colored with the secondary coloring, and the other parts are colored with the primary coloring, resulting in a strong and noticeable color contrast.In addition, when there is no bleaching process, the corner areas are colored with the primary coloring and the other parts are colored with the primary coloring. The color overlaps with the color of the next coloring, and the other parts appear as the color of the first coloring.

Note that the electrolytic bath used for the anodic electrolytic treatment in this process is not specified and may be determined as appropriate from the viewpoint of economic efficiency and workability. Although it is possible to use an electrolytic coloring bath that has been subjected to coloring, an alkaline bath easily dissolves alumite, so an acidic bath to which an acid or a salt thereof is added is preferable.

(4) Secondary coloring treatment The treated material that has been subjected to each of the above treatments can then be subjected to secondary coloring using a coloring method that provides a different tone from the primary coloring. When it is dissolved and removed, the color tone of the primary coloring is maintained in areas other than the corner areas, and only the corner areas are colored in a different color tone due to the secondary coloring. In this case, the electrolytic coloring method may be used for the secondary coloring as in the primary coloring, or a different coloring method such as a dyeing method may be used.

(5) Paint film dissolution and repainting treatment If the paint film surface by dip coating applied in the painting process of (2) above is subjected to decolorization treatment or secondary coloring treatment in the third and fourth steps, The coating surface may lack smoothness or have uneven gloss, so it is unsuitable for use as a protective coating, either as is or by further baking and drying. This is especially noticeable when used. Therefore, in this step, the material to be treated after undergoing each of the above treatment steps is immersed in a bath containing an organic solvent to dissolve the coating film on the surface, and then painted again to form a protective coating film.

In this case, when dissolving the paint film and repainting in this process, if the material to be treated is immersed in a paint bath containing a solvent with strong paint solubility, such as TFS painting, the previous paint film will be removed by immersion. Since it is dissolved, if it is pulled out of the bath as it is, it becomes possible to paint with a new coating surface, and both the dissolution and painting processes can be performed in the same bath.

The bath conditions used for dissolution will of course vary depending on the type of paint used in step (2) above and the subsequent drying conditions, but generally speaking, it is necessary to determine the bath conditions from the viewpoint of safety such as fire prevention and solubility of the paint film. Solvents such as trichlorethylene, tetrachlorethylene and carbon tetrachloride are particularly preferred.

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 A rectangle with one side of 40 mm and a corner radius of curvature.
An extruded aluminum profile of 6063S-T5 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 10 μm is formed on the surface of the aluminum profile, and 50 g/l of nickel sulfate and 40 g/l of boric acid are added.
DC cathode electrolysis was carried out for 30 seconds at a current density of 0.5 A/dm ² using a nickel plate as an anode at a bath temperature of 30° C. to obtain a uniform bronze coloring.

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. Then, add this shape to 150 ml of sulfuric acid.
When anodic electrolytic treatment was performed for 3 minutes at a voltage of 15 V in a bath with a temperature of 20°C 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 this corner part bleached is selenium dioxide 15g/l, copper sulfate 0.6g/l, zinc sulfate 0.3
When DC cathode electrolysis was performed at a voltage of 13 V for 3 minutes using carbon as an anode in a bath with a temperature of 20°C and a temperature of 20°C, the corners were colored gold.
A bronze-colored colored film was obtained except for the corner portions.

Next, this shape was immersed for 5 minutes in a tetrachlorethylene bath with a bath temperature of 90°C, and then a voltage was Perform anodic electrolysis at 150V for 2 minutes and heat to 190℃.
After baking for 30 minutes at a temperature of
A pattern-colored shape with a beautiful coating surface was obtained.

Example 2 An extruded aluminum material (6063S-T5) having the same shape and dimensions as Example 1 was subjected to the same anodizing treatment and electrolytic coloring treatment (primary coloring) as in Example 1, and then treated with Toa Paint Co., Ltd. After applying the paint using TFS paint Toatri Paint S8001 (AL-2) manufactured by Manufacturer Co., Ltd. at a drawing speed of 0.5 m/min using a paint bath with a bath temperature of 80°C and a solid content concentration of 12%, the formation of an anodized film was When anodic electrolysis treatment was carried out for 5 minutes at a voltage of 15 V in the electrolytic bath used, only the corner portions were bleached, and the other portions remained bronze-colored.
(The coating film thickness other than the corner parts is approximately 1μm).

When the shape after the decolorization treatment was subjected to cathodic electrolytic coloring treatment (secondary coloring) in the same selenium dioxide bath as in Example 1 at a voltage of 12 V for 3 minutes, the corner portions were colored gold.

Next, after immersing the TFS paint Toa Tori Paint S8001 (AL-2) manufactured by Toa Paint Co., Ltd. in a paint bath with a bath temperature of 80°C and a solid content concentration of 20% for 7 minutes,
When the material was pulled up at a speed of 1.8 m/min and baked and dried at 190°C for 30 minutes, a patterned colored shape with a beautiful coating surface was obtained.

Example 3 A rectangle with one side of 50 mm and a corner radius of curvature
A 6063S-T5 aluminum extrusion shape with a cross section of 0.5 mmR was cut into lengths of 200 mm, and after normal pretreatment, it was electrolyzed with 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 60°C for 5 minutes, anodic electrolysis was performed at a voltage of 15V for 5 minutes in the sulfuric acid bath originally used to form the anodic oxide film, and each corner was bleached, but All other surfaces remained pale bronze in color.

The shape with this corner part bleached is tinned with tin sulfate 5
When alternating current electrolysis was carried out for 3 minutes at a voltage of 12 V using 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.

Thereafter, the same melting treatment and painting treatment as in Example 1 were performed, and a patterned colored shape with a beautiful coated surface was obtained.

Example 4 A 6063S-T5 aluminum extrusion section having a rectangular cross-section with a side of 75 mm and a corner radius of curvature of 1 mmR was cut to a length of 200 mm, subjected to normal pretreatment, and then treated with 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,
Furthermore, tin sulfate 5g/l, sulfuric acid 7g/l, bath temperature 20
With carbon as the counter electrode in an electrolytic bath at ℃, voltage 12V,
AC electrolysis was carried out for 2 minutes 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 at a temperature of 80°C for 5 minutes, 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.
2 μm) Copper sulfate 10
When alternating current electrolysis 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 20 g/l of sulfuric acid and a bath temperature of 20°C, the corner portions were colored reddish brown.

Next, the shape was immersed in a trichlorethylene bath with a bath temperature of 80°C for 5 minutes, and then immersed in a bath made by Toa Paint Co., Ltd.
TFS paint, Toatori Paint S8001 (AL-
2) Immerse it in a paint with a bath temperature of 80℃ and a solid content concentration of 20% and pull it up at a speed of 1.8m/min.
After baking and drying for a minute, a patterned colored shape with a beautiful coating surface was obtained.

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 coated with paint by dipping. After that, a drying process was carried out at a temperature of 60℃ for 5 minutes, and then an anodizing process was carried out at a voltage of 15V for 3 minutes in a bath containing 50g/l of oxalic acid for 3 minutes to decolorize the corner parts. When immersed for 10 minutes in a dyeing bath containing 5 g/l iron ammonium 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 outside the corners. Obtained.

Next, the shape was immersed in a trichlorethylene bath at a bath temperature of 80°C for 5 minutes, and then electrostatically coated using Porin AL Clear UN, a solvent-based paint manufactured by Shinto Toyo Co., Ltd., at a temperature of 130°C. After baking and drying for 5 minutes, a patterned colored shape with a beautiful coated surface was obtained.

Example 6 A rectangle with one side of 40 mm and a corner radius of curvature
A 6063S-T5 aluminum extrusion shape with a cross section of 0.4 mmR was cut into 200 mm pieces, 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
Anodizing was performed at 1.2A/ ^dm2 for 30 minutes to form an anodic oxide film of approximately 10μm on the surface of the aluminum profile, and 50g/l of nickel sulfate and 40g/l of boric acid were applied.
l. Using a nickel plate as the anode in a bath with a bath temperature of 30℃.
Direct current cathode electrolysis was carried out at 0.5 A/dm ² for 10 seconds to obtain uniform light brown coloring.

Next, the above-mentioned colored shapes were coated with AL-
200-50 resin content 15% aqueous solution, 0.6m/
The profile was pulled up at a pulling speed of 100 ml, dried at a temperature of 80°C for 5 min, and manganese sulfate 70 g/l was removed.
When DC cathode electrolysis was performed for 30 seconds at a voltage of 60 V using carbon as an anode in a bath containing 20 c.c./l of hydrogen peroxide solution (35%) at a bath temperature of 20°C, the corner part became a dark gold color. A patterned colored film was obtained in which the areas other than the corner portions were light brown.

When this was further subjected to the same melting and painting treatments as in Example 1, a patterned colored shape with a beautiful coated surface was obtained.

As described above, according to the method of the present invention, when applying a pattern coloring to aluminum after an anodic oxide film has been formed, a series of treatment steps including two coloring treatments before and after is performed to form corners on the surface of the material to be treated. It is possible to obtain a colored film with a pattern that differs in color from the other parts. Therefore, if this is applied to the surface treatment of various aluminum materials, including aluminum extrusion shapes for interior fittings, existing equipment can be used. It is now possible to easily create multicolored patterns by using
Its high productivity, excellent durability, and the ability to obtain colored films with beautiful patterns make it 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, dip coating is applied to the surface of the material to be treated to increase the thickness of the film at the corners and other parts. A coating film with a different distribution is formed, and then, if necessary, this treated material is subjected to anodic electrolysis in an acidic aqueous solution to selectively decolorize only the corner portions of the treated material,
After that, secondary coloring by electrolytic coloring or dyeing is applied to color only the corner parts of the material to be treated, and after obtaining a patterned colored film on the surface of the material to be treated with different tones between the corner part and other parts, further organic A method for pattern coloring aluminum or aluminum alloy, which comprises immersing the material to be treated in a bath containing a solvent to dissolve the coating film on the surface and repainting.