JPS6014118B2 - Surface treatment method for aluminum or aluminum alloy - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel surface treatment method for producing a film with a beautiful pattern on the surface of aluminum or an aluminum alloy (hereinafter simply referred to as aluminum) by an electrochemical method.

This kind of pattern forming method using electrochemical surface treatment is described in Tokugan Sho 50-1136485 and Patent Application Sho 51-2755, which the present inventors previously developed and successfully put into practical use.
If this invention is applied to the surface treatment of aluminum, a pattern can be created on the surface of the treated material using conventional embossing methods, printing methods, etching methods using partial masking, or photoetching methods. Unlike the case where aluminum is exposed to aluminum, vertical striped patterns can be formed on the surface of aluminum using ordinary electrochemical processing equipment, without requiring special equipment or mechanical equipment such as molds or plates. This method is attracting attention as a promising and innovative method for producing decorative aluminum materials, as it is simple and allows for cost savings, and the film has excellent weather resistance. The method of the invention includes: Pre-treatment step: First, oil and dirt adhering to the surface of the object to be treated are removed.

[Raw pattern forming process: Next, an inert material is formed in an electrolytic bath consisting of an aqueous solution to which an alkali or alkaline metal hydroxide or a salt thereof, or an organic or inorganic acid that tends to form a barrier film is added thereto. AC electrolysis is carried out using the material as a counter electrode, and a film with a vertical striped pattern is formed on the surface of the object by the action of bubbles generated during AC electrolysis.

Shiichi Pattern coloring process: The above process (.

) can be clearly colored by a known metal salt bath alternating current electrolytic coloring method or a coloring treatment using dyes or pigments, or a protective film can be formed by anodization treatment beforehand. After improving the corrosion resistance and abrasion resistance, the above-mentioned coloring treatment is applied to clearly color the striped pattern. In addition, when performing anodizing treatment prior to pattern coloring, lightly etching the object to be treated with an aqueous solution of sodium hydroxide or sodium carbonate before treatment will result in a more vivid colored pattern in the subsequent coloring treatment. can be done.

W Post-treatment process: Finally, sealing with steam or heated water or coating with transparent resin is performed. It consists of the above-mentioned steps, and all of the steps are comprised of electrochemical steps such as immersion in a treatment medium, energization, and heating.

The most important step among these is the pattern formation step (o) by AC electrolysis, and the reaction mechanism for the appearance of the pattern is estimated from observation of the cross section of the film using an electron microscope. A part of the mold film is destroyed and many bubbles rise from this part along the surface of the object to be treated and rise above the electrolyte surface. A large difference in electrolytic action occurs between the area traced by the air bubbles and other areas, and many pores are generated in the area where the air bubbles pass, and the electrolytic action after the initial stage of electrolysis is concentrated in the area where the air bubbles pass. This is thought to be for the purpose of

In other words, the part where the air bubbles pass becomes the "streak" part with a cotton pattern, but if the electrolyte is processed while it is stationary without making too many borders, it will be formed on the surface of the object to be processed. A cotton pattern appears as a vertical striped pattern that continues intermittently in the vertical direction, with the "streaks" being almost straight lines, such as the pattern shown in Figure 7. If you ignore the color, you can see this. The shape of the pattern formed during the process determines the decorative effect of the final product. As mentioned above, the combination of linear "streak" patterns has an excellent decorative effect and has an aesthetic appearance that can be used for practical purposes, but moreover, the composition of the pattern is relatively Due to its simplicity, it lacks variety, and it cannot be denied that it is somewhat boring. Therefore, as a result of intensive research on this point, the inventors of the present invention have found that in the pattern forming process, there is no effect on the upward path of bubbles on the surface of the treated object during AC electrolysis for pattern formation. By providing this obstacle and bending or blurring the upward path of the bubbles, we can create various changes in patterns consisting of combinations of simple straight lines, and change the surface of the treated object. We succeeded in creating a completely new fluid pattern and significantly improving the design and decorative effect of the product.

Hereinafter, embodiments of the present invention will be explained in detail with reference to the drawings. As the obstacle 1 in the pattern forming step, for example, chemical-resistant silk (not limited to netting, cloth, etc.) as shown in FIG. 1 may be used. After the pretreatment, the material is spread over the surface of the object to be treated 2 as shown in the figure, and then immersed in an electrolytic bath (not shown) for pattern-forming AC electrolytic treatment. After applying, take it out from the tank, wash it with water, and remove obstruction 1.
If you remove it and then apply the normal coloring treatment or protective film coloring treatment mentioned above, the surface of the object to be treated 2 will have a 6th layer.
Colored pattern film 3 including fluid curves as shown in the figure
is obtained. Furthermore, FIGS. 3 to 5 show typical embodiments of the method of the present invention, and the silk that becomes the obstacle 1 is made of chemical-resistant material so that it can be easily attached and detached during the treatment process. It is extremely convenient for the work if suction cups 4 made of rubber are arranged and attached at key points and the obstacles 1 such as a net are attached and fixed to the surface of the object 2 to be treated using the suction cups 4. Note that when the suction cups 4 are used, traces as shown in FIG. 5 are left on the surface of the product 5, so if these are arranged regularly and the obstacles 1 are fixed on the surface of the object 2 to be treated, the above-mentioned Together with the change in pattern caused by the obstacles 1, this serves to further enhance the decorative effect of the design of the product 5. Next, typical examples of the surface treatment method according to the present invention and comparative examples thereof will be listed.

Example 1 An aluminum profile 606$-T5 was pretreated by a conventional method, and then a net was placed on the surface of the object 2 to be treated as shown in FIG. Sodium shelf acid 0.3 mol/〆 and shelf acid 0.1 mol/immersed in the aqueous solution, using a stainless steel plate as the counter electrode, frequency 60
When the HZ alternating current was applied for one cycle at 30 y, a wood grain pattern appeared on the surface of the aluminum profile.

After removing the net, 450g/40g of the same was immersed in a sodium carbonate aqueous solution for 2 minutes, and then 150g/of the same was anodized in a sulfuric acid solution at 16V for 3 minutes, and then an aqueous solution containing stannous sulfate. When the alternating current electrolytic coloring treatment is applied in the interior, the surface of the profile 5 shown in FIG. 2 has an amber flowing wood grain pattern in which the "streaks" of the wood grain are darkly colored, as shown in FIG. 6. An aluminum profile with a coating 3 was obtained, which was finally treated with a mist coat of transparent resin. Example 2 An aluminum profile 606$-T5 was pretreated by a conventional method, and then a net with suction cups 4 serving as an obstacle 1 was stretched over the surface of the object 2 to be treated as shown in FIG. Sodium chloride 0.3 mol/dip was immersed in an aqueous solution of 0.1 mol/sodium acid, and a stainless steel plate was used as a counter electrode at a frequency of 60.
When a 30 V HZ alternating current was applied to the product, a wood grain pattern appeared on the surface of the aluminum profile.

After removing the net, 450g/40g' of the same was immersed in an aqueous sodium carbonate solution for 2 minutes, and then anodized in a sulfuric acid solution of 150g/16V for 30 minutes, and then immersed in an aqueous solution containing stannous sulfate. When the alternating current electrolytic coloring treatment is applied to the surface of the profile 5, a wood grain pattern coating 3 as shown in FIG.
An aluminum profile with a . Example 3 A 606$-T5 aluminum profile was pretreated by a conventional method, and then placed in a bath containing 15 g of boric acid and 1 g of sodium hydroxide, with an obstacle attached as shown in Figure 1, to the counter electrode. When an AC current of 35 V was applied to stainless steel for one minute, a gray wood grain pattern was formed on the surface of the profile.

This profile is then treated with an inorganic colored oxide containing stannous sulfate (
7000) and finally coated with a concentrated transparent resin paint, a beautiful aluminum shape with a wood grain pattern as shown in Figure 6 with only the wood grain part colored was obtained.
Example 4 After pre-treating aluminum 606$-T5 using a conventional method, stainless steel was placed on the opposite electrode in a 0.3 hol/room of trisodium phosphate with an obstacle attached as shown in Figure 1. When an alternating current was applied for 15 minutes at a current density of 2.0 A/d, a silver-gray wood grain pattern was formed on the surface of the building material.

Next, this shape was soaked in a sodium hydroxide solution (30g'),
After washing with water, soak in a sulfuric acid bath at a temperature of 20°C and a current density of 1. secretion/d mede3
The powder was anodized to form an anodized film about 1 sail thick on the surface of the shape. After washing with water, it was immersed in an aqueous solution of ferric ammonium oxalate at a concentration of 40 g for 5 minutes for coloring, and a colored wood grain pattern as shown in FIG. 6 was developed on the surface of the shape. Finally, it was immersed in boiling water for about 3 minutes to perform a pore-sealing treatment to obtain a beautiful aluminum profile with a pale yellow plain wood-like pattern.

Example 5 An aluminum profile 606$-T5 was pretreated by a conventional method, and then, in a bath of 0.3 g of calcium hydroxide, with an obstacle attached as shown in Figure 1, a stainless steel material was placed on the opposite electrode. When an alternating current was applied for 15 minutes at a current density of 2.0 A/d, a silvery-gray white wood grain pattern was formed on the surface of the treated material.

Thereafter, the material to be treated was anodized and colored in the same manner as in Example 4, and an aluminum material having a clear colored wood grain pattern as shown in FIG. 6 was obtained. Comparative Example Aluminum profile 606$-T5 was pretreated by a conventional method and treated with 0.3 hol of sodium metashelate and 0.1 m of shelate acid.
When an alternating current with a frequency of 60 Hz was applied at 30 V for 15 minutes using a stainless steel plate as a counter electrode in an aqueous solution thereof, a wood grain pattern appeared on the surface of the aluminum profile.

Next, this was immersed in 45° C. in a sodium carbonate aqueous solution, and then immersed in 150 g of sulfuric acid solution at 16 V, 30
When the anodizing treatment was performed for 1 minute, and then the AC electrolytic coloring treatment was performed in an aqueous solution containing stannous sulfate, the "streaks" of the wood grain were darkly colored on the surface of the object 2, as shown in Figure 7. An aluminum profile having a woodgrain pattern film 3 consisting of a combination of straight lines was obtained, and finally, a transparent resin was coated with a mist coating to complete the process.

As described above, in the aluminum surface treatment method according to the present invention, when a colored film with excellent film characteristics and a beautiful cotton pattern is generated on the surface of the object to be treated using an electrochemical method, after the pretreatment process is completed, An obstacle is provided on the surface of the workpiece to change the upward path of bubbles during AC electrolysis, and the presence of this obstacle changes the upward path of bubbles generated during AC electrolysis in the next vertical stripe pattern formation step. change into form,
Since it is possible to obtain not only a simple vertical striped pattern but also various patterns on the surface of the treated object, this can be applied to aluminum sashes, fittings, and panels for buildings, as well as car steel, household appliances, and decorative aluminum materials. It has optimal utility value when applied to the production of products such as.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an object to be treated to which an obstacle is attached, which is used in the pattern forming step of the surface treatment method according to the present invention;
Fig. 2 is a perspective view showing a product after forming a cotton-patterned film, Fig. 3 is a perspective view showing a workpiece to which an obstacle is attached according to another embodiment, and Fig. 4 is a perspective view showing the object to be treated with obstacles attached to it according to another embodiment. FIG. 5 is a perspective view showing the structure of the attached suction cup, FIG. 5 is a perspective view showing the product after forming the patterned film obtained by the embodiment shown in FIG. 3, and FIG. 6 is the film formed on the surface of the product by the method of the present invention. FIG. 7 is a front view replicating the pattern of a film formed on the surface of a product according to a comparative example of the present invention. 1... Obstacle, 2... Nuclear processing material, 3... Film, 4...
・Sucker, 5...product, 6...trace. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7

Claims (1)

[Claims] 1. In an electrolytic bath consisting of an aqueous solution in which an alkali or alkaline earth metal hydroxide or a salt thereof, or an organic or inorganic acid that tends to form a barrier film is added to a workpiece made of aluminum or an aluminum alloy. AC electrolysis is applied to the surface of the object to be treated to form a film with a vertical striped pattern due to the action of bubbles generated during AC electrolysis, and then this film is subjected to AC electrolysis treatment in a bath containing metal salts or dye, Either a coloring treatment is performed by dipping in pigment, or a protective film is applied to the surface of the vertical striped pattern film by anodizing treatment before that, and then the above-mentioned coloring treatment is performed to make the pattern clearer and the object to be treated is In a series of treatment steps to generate a beautiful striped colored film on the surface, obstacles are provided on the surface of the object to be treated after the pretreatment step to change the bubble upward path during AC electrolysis, Due to the presence of this obstacle, the ascending path of the bubbles generated during AC electrolysis in the next vertical stripe pattern forming step is changed to a desired shape, and the surface of the processed object is not only a simple vertical stripe pattern, but also various patterns. A method for surface treatment of aluminum or aluminum alloy, characterized in that: