JPS6011118B2 - Surface treatment method for aluminum or aluminum alloy - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a novel surface that produces a film with a beautiful striped pattern on the surface of aluminum or aluminum alloy (hereinafter simply referred to as aluminum) using a flea chemistry method. Regarding processing method.

This type of pattern forming method using electrochemical surface treatment is based on Tokugan No. 85, 1985, and Tokbuta No. 51-27,556, which the present inventors had previously developed and successfully put into practical use. If there is an invention and this invention is applied to the surface treatment of aluminum, it will be possible to create a pattern on the surface of the object to be treated using the conventional empos method, printing method, etching method using partial masking, photoetching method, etc. Unlike conventional methods, vertical striped patterns can be formed on the surface of aluminum using ordinary electrical and mechanical processing equipment without the need for 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 because it is simple and allows for cost savings, and the film has excellent anti-aging properties.

The method of the invention is as follows: Pre-treatment step: First, oil and dirt adhering to the surface of the object to be treated are removed.

‘.

'Pattern forming process: Next, an inert material is mixed in an electrolytic bath consisting of an aqueous solution containing an alkali or alkali metal hydroxide or a salt thereof, or an organic acid or inorganic acid that tends to form a barrier film. AC electrolysis is performed 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. 1. Pattern coloring process: The striped pattern film in step 'o' above is vividly colored by a known metal salt bath alternating current electrolytic coloring method or coloring treatment by immersion in dyes or pigments, or it is colored with an anode before that. After forming a protective film by oxidation treatment and improving the corrosion resistance and abrasion resistance of the film, the above-mentioned coloring treatment is performed to vividly color the striped pattern.

6 Post-treatment process: Finally, sealing with steam or heated water, or coating with transparent resin.

It consists of the above-mentioned steps, all of which consist of electrochemical steps such as immersion into the treatment chamber, energization, and heating.

The most important process among these is the pattern formation process by AC electrolysis.The reaction mechanism for the pattern appearance is estimated from observation of the cross section of the film using an electron microscope. A part of the mold film is destroyed and a large number of bubbles rise from this part along the surface of the workpiece to the electrolyte surface. A large difference in electrolytic action is created between the traced part by the bubbles and other parts, and many pores are generated in the part where the bubbles pass, and the electrolytic action after the initial stage of electrolysis is concentrated in the part where the bubbles pass. This is thought to be due to the fact that the areas through which these bubbles pass are colored darker and more vividly than other areas in a later process, resulting in a ``streak'' pattern that is intermittent in the vertical direction.

The elements that determine the physical design of the pattern formed on the surface of the workpiece through each of the above steps include the shape of the "streak" part of the striped pattern, such as the inside, length, depth, etc. In addition, the density of "streaks" on the surface to be treated, and "
These factors include the contrast between the shading of the coloring between the "streaked" part and the non-streaked part (surface part), and the surface condition of the "face" part, that is, surface roughness and gloss. Of these, the shape and density of the "streaks" depend on the processing history of the workpiece, such as melting, casting, heating, rolling, and extrusion, before pretreatment, and all processing conditions from pretreatment to electrolysis and coloring. The shading and contrast of the coloring are mainly determined by the electrolytic and coloring treatment conditions after pretreatment, and the surface condition of the "face" part is determined by the surface roughness or gloss at the end of the pretreatment. .

The present inventors have noticed that, among the above-mentioned factors, the surface condition of the treated object at the end of the pre-treatment process has an extremely large influence on the design effect of the pattern formation of the final product. In the pretreatment process of the workpiece, in addition to the process of removing dirt such as oil and buffing with ordinary detergents and organic solvents and combining it with alkaline etching, we also newly roughen the surface of the workpiece. Through this experiment, we succeeded in obtaining a product with a colored pattern film that has a variety of decorative effects that are completely unseen in conventional products.

That is, in the method of the present invention, when forming a striped colored film on the surface of aluminum, first, as a pretreatment, the surface is roughened by mechanical, chemical, or electrochemical matte treatment or milky white treatment. processing, and then subjecting it to alternating current electrolysis in an electrolytic bath consisting of an aqueous solution containing an alkali or alkaline earth metal hydroxide or a salt thereof, or an organic or inorganic acid that tends to form a barrier film thereon,
A film with a vertical striped pattern is formed on the surface of the object to be treated by 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 by immersion in dyes and pigments. Either a coloring treatment is applied or, before that, a protective film is applied to the surface of the vertical striped pattern film by anodic oxidation treatment, and then the above coloring treatment is applied to clarify the pattern and create a beautiful cotton pattern on the surface of the treated object. It is characterized by obtaining a patterned colored film.

In this case, the sandblasting method and the liquid honing method are used for mechanical roughening of the surface of the treated object, and when applying the sandblasting method, coarse abrasives are used for the roughening process. If you spray it on the surface of an object with compressed air, you can get a rough polished surface, but if you use fine-grained abrasives (#100 or higher), the sandblasting method generates a lot of dust, making the work difficult. Therefore, a liquid honing method in which a mixture of an abrasive and a liquid is sprayed onto the treated surface using compressed air is suitable, and in this case, a satin polished surface with a fine texture with a fine unevenness distribution is obtained.

In addition, for chemical satin treatment, various organic acids, inorganic acids, or their salts are added to chemicals such as caustic soda, hydrofluoric acid, and hydrochloric acid for the purpose of adjusting the roughness of the satin finish, stabilizing the bath, and preventing the generation of harmful gases. is used. Furthermore, there are two types of electrochemical satin finish treatment: the direct current method, in which electrolytic treatment is carried out using the material to be treated as an anode, and the alternating current method, in which electrolytic treatment is carried out by applying alternating current to a counter electrode. Either of these methods may be used. Of these, the alternating current method is particularly suitable for milky white processing. These treatment grades include, for example, sulfuric acid grade, sulfuric acid-hydrochloric acid grade, caustic soda/gluconate sodium chloride, and the like. In addition, when anodizing is performed prior to pattern coloring, lightly etching the treated material with an aqueous solution of sodium hydroxide or sodium carbonate before anodizing will help create a more clearly colored pattern in the subsequent coloring process. can be expressed.

As described above, the present invention is applicable to mechanical, chemical, or electrochemical processes in the pretreatment process when producing a film with a beautiful striped pattern with excellent film properties on an aluminum material using an electrochemical method. The surface condition of the object to be treated is adjusted by roughening the surface with satin finish or milky white treatment, thereby making the surface after treatment matte as a whole and forming the striped pattern ``stripes''. By freely changing the contrast between the image and the rest of the image, it is also possible to intentionally blur the outline of the striped pattern and create subtle fluctuations.

Therefore, according to the present invention, it is possible to obtain a patterned aluminum material with a very wide variety and excellent decorative effect, and it can be used for aluminum sashes, fittings, and panels of buildings, as well as for military and home use. If it is applied to the production of household appliances, decorative aluminum materials, etc., it will have an optimal utility value. Some specific examples showing embodiments of the method of the present invention are listed below.

Example 1 An aluminum plate material 105 and 14 days old were degreased by a conventional method, and cinnabar sand with a particle size of 30 to 60 mesh was coated on the surface of the aluminum plate material 9.
19 stages/at an angle of 45o (distance from the nozzle to the surface 3 degrees) using a 4K9' air pressure from a 5-bar diameter nozzle.
d) Spray to obtain a pear-like surface.

This was washed with a 3% phosphoric acid aqueous solution, and then an alternating current of 60 Hz frequency was applied at 30 V for 18 minutes using a stainless steel plate as a counter electrode in the aqueous solution containing 0.3 hol/sodium metachloride/so and 0.1 mol of phosphoric acid. Then, a wood grain pattern appeared on the surface of the object to be treated. This was further concentrated for 2 minutes in the sodium carbonate aqueous solution at 45°C for 40 evenings, and then 1
When the anodizing treatment was carried out for 30 minutes at 16 V in a sulfuric acid bath for 50 evenings, and then the alternating current decoloring treatment was carried out in an aqueous solution containing nickel sulfate, the "streaks" of the wood grain pattern were darkly colored. A beautiful aluminum plate with a satin finish on the sides other than the lines was bound. Finally, a transparent resin was applied to the fins to complete the process. Example 2 Aluminum plate material 105 Misakihichi 14 was degreased by a conventional method and treated with a commercially available chemical satin finish treatment agent Dipsol AI.
-70480 Yu/So, 3 When treated in ○○ for 2 minutes and washed with water, a pear surface is obtained.

Next, sodium metaside acid 0.3 hoi/〆, shelf acid 0.1
mol/When a stainless steel plate is used as the counter electrode in the aqueous solution and AC with a frequency of 60Hz is applied at 30V to each powder,
A wood grain pattern appeared on the surface of the treated object. Add this to 45
qC, 40 ta' in the sodium carbonate aqueous solution for 2 minutes, then 150 ta' in the sulfuric acid bath at 16 V,
When anodic oxidation treatment is performed for 30 minutes and then AC electrolytic coloring treatment is performed in an aqueous solution containing stannous sulfate, the "streaks" of the wood grain pattern become darkly colored, and the "surfaces" other than the "streaks" become dark. A beautiful aluminum plate material with a satin finish was obtained. Finally, the process was completed by painting the transparent resin with military uniform. Example 3 Aluminum plate material 1050P-14 was degreased by a conventional method and treated with 5 mol of caustic soda and 2 mol of it.
Electrolytic satin polishing is performed in an aqueous solution of sodium gluconate (5 mm) using the steel plate as a cathode at a rate of 20 to 3 ships/day for 8 minutes to obtain a satin finish.

After washing this with water, sodium metashelate 0.3 hol/〆,
When alternating current at a frequency of 60 Hz was applied to each powder in three layers using a stainless steel plate as a counter electrode in an aqueous solution containing 0.1 mol of shelf acid, a wood grain pattern appeared on the surface of the object to be treated. This was further concentrated at 45°C for 2 minutes in the sodium carbonate aqueous solution for 40 evenings, and then immersed at 16V in the sulfuric acid bath for 150 evenings.
After 30 minutes of anodic oxidation treatment, and then AC electrolytic coloring treatment with nickel sulfate, a wood grain pattern with "streaks" is created.
A beautiful aluminum plate material was obtained in which the ``stripe'' portion was darkly colored and the ``surface'' portion other than the ``streak'' had a satin finish. Finally, the process was completed by coating with transparent resin. Example 4 Aluminum plates 105 and 14 were degreased by a conventional method, and treated with 15% antimony sulfate and 14% sulfamic acid.
0% aqueous solution (7 pi○) with the stainless steel plate as the counter electrode, electrolytic polishing was performed by alternating sand between 20 and 3 ships/day, followed by 50 days/day of caustic soda and 50 nights/day of phosphorus. Wash in an aqueous solution of acid soda for three times.

As a result of the above treatment, the surface of the aluminum to be treated becomes a milky-white film-like satin surface, which is then washed with water and then treated with 0.3 mol of sodium metabalate and 0.1 mol of shelactic acid as a counter electrode. Frequency 60H using stainless steel plate
When an alternating current of Z was applied for 15 minutes at 30 y, a wood grain pattern appeared on the surface of the object to be treated. Further, this was heated at 45℃ for 40 evenings/
It is soaked in the sodium carbonate aqueous solution for 2 minutes, and then anodized for 30 minutes at 16V in the sulfuric acid bath for 150 minutes. Next, when subjected to AC electrolytic coloring treatment using stannous sulfuric acid, the "streaks" of the wood grain pattern are darkly colored, and the "surfaces" other than the r-stripes are a beautiful aluminum plate with a milky white satin finish. was gotten. Finally, the process was completed by painting the transparent resin with military uniform. Example 5 Aluminum profile 6066-T5 was processed into a sludge in the same manner as in Example 1, and then treated with boric acid 15 days/Z and sodium hydroxide 1 day/in a bath, using stainless steel as the counter electrode. When AC was applied for 10 minutes at 35 V, a silver-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 (
70°C) and finally coated with a concentrated transparent resin paint, a beautiful aluminum shape with only the wood grains colored was obtained. Example 6 Aluminum material 60
After roughening the surface of 6$-T5 using the same machine as in Example 1, 0.3 mol of trisodium phosphate was added in the solution.
Using stainless steel as the counter electrode, the alternating current density is 2. Mountain A
When electricity was applied for 15 minutes at /d, a silver-gray wood grain pattern was formed on the surface of the treated material.

Next, this profile was soaked in sodium hydroxide solution (30 tsp, 6 tsp).
After soaking in water for about 1 minute and rinsing with water, soak at a concentration of 150 ml.
In a sulfuric acid bath at a temperature of 20°C, the current density is 1. secretion/d mede 30
Anodic oxidation treatment was performed for a minute to form an anodic oxide film with a thickness of about 10 μm on the surface of the profile. After washing with water, it was immersed in an aqueous solution of ferric ammonium oxalate at a concentration of 40 μm for 5 minutes to be colored, and a clear colored wood grain pattern was developed on the surface of the shape. Finally, the material was immersed in boiling water for about 3 minutes for pore sealing, resulting in a beautiful aluminum mold with a pale yellow, white wood-like pattern. Example 7 An aluminum profile 606$-T5 was roughened in the same manner as in Example 1, and then treated with 0.3% calcium hydroxide.
In the evening, when alternating current was applied for 15 minutes at a current density of 2.0 A/d using stainless steel as the counter electrode, a silver-gray white wood grain pattern was formed on the surface of the treated material.

Claims (1)

[Claims] 1. A workpiece made of aluminum or an aluminum alloy is first subjected to surface roughening by mechanical, chemical, or electrochemical satin treatment or milky white treatment as a pretreatment, and then treated with an alkali or alkaline earth metal. AC electrolysis is performed in an electrolytic bath consisting of an aqueous solution containing hydroxides, their salts, or an organic or inorganic acid that tends to form a barrier type film. A film with a vertical striped pattern is formed by the action of Aluminum or aluminum characterized in that a protective film is formed on the surface of the vertical striped film by treatment, and then the above coloring treatment is applied to sharpen the pattern to obtain a beautiful striped colored film on the surface of the object to be treated. Alloy surface treatment method.