JPS607714B2 - Surface treatment method for aluminum materials - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for applying electrical treatment to the surface of a molded product such as a plate or an extruded shape made of aluminum or an aluminum alloy (these are referred to as aluminum materials in this specification). This invention relates to a method for forming beautiful wood grain patterns.

As a secondary method, methods for creating patterns such as wood grain patterns on the surface of aluminum materials include: ■ A method of stamping predetermined scoring lines on the surface of aluminum materials using a pressure roll or a press mold.

'B} A method of etching the surface of an aluminum material using photoengraving and engraving the original image.

{C} A method in which the surface of the aluminum material is partially masked with an appropriate protective material, and then sprayed with paint, chemically dyed, or colored with an oxide film.

Plate A method of printing paint or other coloring materials on the surface of aluminum materials by means such as screen printing or transfer printing.

In addition, there is a method in which patterned paper or patterned film on which a wood grain pattern is printed is attached to the surface of the aluminum material.

However, the embossing method used in this example is a method in which the workpiece is compressed while being strongly compressed with a pair of dies or molds, so it can only be applied to flat aluminum materials, and it is also possible to use a pair of dies or molds. The drawback is that it requires a large amount of cost to produce. Also, the etching method of [B-]
The masking method and the rib printing method of 'q not only require time and effort in the masking process and plate making of the wood grain pattern, but also the subsequent secondary treatment is extremely troublesome, and there are problems with the durability of the pattern-forming film. Furthermore, all of these methods, including patterned paper pasting, require special machinery and equipment, which makes processing costs very high, especially for aluminum materials with complex shapes, such as extruded profiles for sashes. It had the disadvantage that it could not be used. The inventors of the present invention have conducted various studies in search of a method for forming wood grain patterns that does not have the drawbacks of the above-mentioned conventional method. As a result, the inventors have conducted various studies to find a method for forming wood grain patterns that does not have the drawbacks of the above-mentioned conventional method. After performing alternating current electrolysis treatment as an electrolytic solution to form a silver-gray white wood grain pattern on the surface of the treated object, this was subjected to a normal anodic oxidation film treatment using an inorganic or organic acid, and then a metal salt was added. When the wood grain pattern is immersed in an inorganic dye or dye or pigment solution, the wood grain pattern is colored darker than other parts, resulting in a clear and beautiful decorative pattern on the surface of the treated object. I found out that it can be done.

The present invention has been made based on the above findings. First, an overview of the method of the present invention will be described. An aluminum material is electrolyzed using an aqueous solution of an alkaline electrolyte or an aqueous solution containing a barrier-type film-forming electrolyte as an electrolyte. Electrolytic treatment under conditions where hydrogen gas is generated on the surface of the aluminum material according to the power waveform (AC electrolysis treatment);
'o - During the above electrolysis, the hydrogen gas bubbles generated on the surface of the object to be processed are caused to rise along the surface of the object to be processed. After carrying out the above electrolysis until a silvery gray-white wood grain pattern is formed, the object to be treated is anodized in an electrolytic solution containing an inorganic acid, an organic acid, or both of these (anodizing treatment); and (b) Metal. The method is characterized by: coloring the surface of the object (coloring treatment) by immersing the object to be treated after the anodic oxidation treatment in a solution of an inorganic colorant, dye, or pigment to which salt has been added.

Hereinafter, the method of the present invention will be explained in detail in the order of steps.

Possible alkaline electrolytes that make up the electrolyte for the initial AC electrolysis treatment include sodium orthosilicate, trisodium phosphate, sodium hydrogen phosphate,
Examples include sodium metashelate, sodium hydroxide, sodium silicate, calcium hydroxide, sodium carbonate, and sodium fluoride, and two or more of these may be used in combination.

Preferred specific examples of the barrier-type film-forming electrolyte which is an optionally added component include phthalic acid, shelf acid, phosphomolybdic acid, and ammonium tartrate. Two or more types of these electrolytes can also be used in combination. Aluminum materials that have been pretreated by conventional methods such as degreasing and etching are subjected to AC electrolysis in an electrolytic solution containing the electrolyte described above under conditions that generate hydrogen gas, and then the hydrogen generated on the surface of the object is electrolyzed. If the gas bubbles are allowed to rise along the surface of the object to be treated, a silvery gray-white wood grain pattern will appear on the surface that extends in the hanging direction (vertical direction) of the object, so the electrolysis is stopped at this stage.

The wood grain pattern appears due to electrolysis when hydrogen gas bubbles of various sizes generated during electrolytic treatment rise from below to the water surface while moving slightly from side to side along the surface of the treated object. There is a large difference in electrolyte between the part of the surface traced by the bubbles and other parts, and the part where the bubbles pass has far more pores than other parts, and the silver This is thought to be because it shines grayish white, and when the surface of aluminum material is actually viewed under a microscope after treatment,
The surface of the area traced by the bubbles is clearly more concave than other areas. AC electrolytic treatment is followed by anodic oxidation treatment in an electrolytic solution containing an inorganic acid, an organic acid, or both of these, and the object to be treated is immersed in an inorganic coloring solution containing a metal salt, or a dye or pigment solution. The process for coloring the surface is not particularly different from the general method of forming a colored oxide film on (unpatterned) aluminum material, which consists of the same processing means, and special acids, metal salts, dyes, and pigments are used. There is no need to use it.

Note that if the object to be treated is lightly etched with an aqueous sodium hydroxide solution prior to the anodizing treatment, a clearer colored pattern can be developed in the subsequent coloring treatment. When anodizing and coloring treatments are applied, the woodgrain pattern, which was silvery gray before these treatments, is colored into a significantly sharper tone by the inorganic metal salts, dyes, or pigments in the coloring agent, and the wood grain pattern is colored to a highly vivid tone. Expressed on the surface.

The colored wood grain pattern is produced by this coloring treatment because many pongee holes are concentrated in the silvery-gray white wood grain pattern formed by AC electrolytic treatment, and metal salts, dyes, and pigments are applied to this area. This is thought to be due to the fact that a much larger amount of coloring components such as these are deposited or adhered to other parts with a smaller pore distribution. In addition, according to the method of the present invention, while developing a colored wood grain pattern, it is also possible to completely eliminate roll marks, scratches, bruises, dice marks, and streaks after anodizing that are found in ordinary processed aluminum materials. I can do it.

As mentioned above, the method of the present invention uses a unique electrochemical treatment to naturally generate a woodgrain pattern on the surface of aluminum material, and the woodgrain area is vividly colored. It is very simple and easy to create a pattern.

Furthermore, the method of the present invention does not require mechanical processing or manual work unlike conventional methods, so it has extremely high productivity. As a result, according to the method of the present invention, it is possible to produce an aluminum material having a colored wood grain pattern at a very low cost. Furthermore, artificial patterns created using conventional methods such as engraving, etching, spraying or phosphorization, and printing tend to feel unnatural due to the repetition of the same pattern. The wood grain pattern formed by the method of the invention is unique and extremely natural, close to true wood grain. Therefore, the surface treatment method of the present invention can be applied to aluminum sashes, fittings, panels of buildings, car bran, household appliances, decorative aluminum materials, etc.
When applied to the treatment of various aluminum materials, which are expected to improve product value by imparting a wood grain pattern, extremely remarkable effects can be achieved. The present invention will be explained below with reference to Examples.

Example 1 An aluminum 606$-T5 profile was pretreated by a conventional method, and sodium metatrate was added 0.2 hol/sodium metatrate/30 t/d.
2. In the middle, stainless steel was used as the counter electrode. sail/
When AC electrolysis was carried out at an electrode density of d, a silvery gray-white wood grain pattern was formed on the surface of the profile.

This formation was then immersed in a sodium hydroxide solution (concentration 30 m/s, temperature 60 q○) for about 1 minute, and after washing with water, the concentration 15
0 evening/sat, in a sulfuric acid bath at a temperature of 20°C, at a current density of 1. secretion/
Anodic oxidation treatment was carried out for 30 minutes at step d to form an anodic oxide film about 10 mm thick on the surface of Katamura. After washing with water, ferric ammonium oxalate was added for 40 minutes/aqueous solution thereof (pH 4.5).
When colored by immersing it in water (temperature 60q○) for 5 minutes, a clear colored wood grain pattern appeared on the surface of the profile. 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 2 An aluminum 606$-Ts profile was pretreated by a conventional method and treated with trisodium phosphate for 30 minutes and sodium fluoride for 8 hours.
Evening: In the bath, a carbon plate was used as the counter electrode, and the alternating current density was 1. When electricity was applied for 2 minutes to pine/d, a silvery gray-white wood grain pattern was formed on the surface of the profile.

Next, this shape was immersed in a sodium hydroxide solution (concentration: 30°C, ordinary temperature: 60°C) for about 1 minute, and after washing with water, Example 1
In the same manner as above, an anodic oxide film with a thickness of about 10 peaks was applied in a sulfuric acid bath. Then, after washing with water, aluminum red (dye manufactured by Gillan, Switzerland) was added for 10 days/6 hours to its aqueous solution (temperature 5000).
After soaking for a minute, a clear colored wood grain pattern appeared on the surface of the profile. Finally, it was sealed by immersing it in boiling water for about 3 minutes to obtain a beautiful aluminum shape with a reddish-brown wood grain pattern.

Example 3 An aluminum material of 110 mm and 14 mm was pretreated by a conventional method, and sodium orthosilicate was heated for 10 hours/day, sodium tartrate was heated for 30 hours/day, and stainless steel was used as the counter electrode.
AC current density 3. When electricity was applied for 15 minutes at Funen/d〆, a silvery gray-white wood grain pattern was formed on the surface of the treated material.

Thereafter, the wood was anodized and colored using the same machine as in Example 1, and a uruminium material with a clear colored wood grain pattern was obtained. Example 4 Aluminum material 606$-T5 was pretreated by a conventional method,
When alternating current was applied for 15 minutes at a current density of 2.0 A/d using stainless steel as the counter electrode in a chamber containing 0.3 hol of trisodium phosphate, a silver-gray wood grain pattern was formed on the surface of the treated material.

Thereafter, the treated material was subjected to sodium hydroxide solution immersion treatment, anodization treatment, and coloring treatment in the same manner as in Example 1, and an aluminum material having a clear colored wood grain pattern was obtained. Example 5 A 1200P aluminum material was pretreated by a conventional method and heated in a sodium hydroxide bath for 2 days, using stainless steel as the counter electrode, and applying alternating current at a current density of 2. When electricity was applied for 20 minutes at M/d, a silver-gray white wood grain pattern was formed on the surface of the treated material.

Thereafter, the treated material was subjected to anodizing treatment and coloring treatment in the same manner as in Example 1, and an aluminum material having a clear colored wood grain pattern was obtained. Example 6
Aluminum material 606$-T5 was pretreated by a conventional method,
Using stainless steel as the counter electrode, alternating current was applied at a current density of 2.0 m in sodium silicate 10 m/m and phthalic acid 5 m/m.
When the current was applied for 5 minutes at 0 A/d, a silvery gray-white wood grain pattern was formed on the surface of the treated material.

Thereafter, the aluminum material was subjected to sodium hydroxide solution immersion treatment, anodization treatment, and coloring treatment in the same manner as in Example 1, and an aluminum material having a clear colored wood grain pattern was obtained. Example 7 An aluminum material of 1050P was pretreated by a conventional method and heated in a sodium hydrogen phosphate bath for 30 minutes, using stainless steel as the counter electrode, and applying alternating current at a current density of 1. When electricity was applied for 10 minutes at anchor/d, a silvery gray-white wood grain pattern was formed on the surface of the treated material.

Thereafter, the treated material was subjected to anodizing treatment and coloring treatment in the same manner as in Example 1, and an aluminum material having a clear colored wood grain pattern was obtained. Example 8
Aluminum material 606$-T5 was pretreated by a conventional method, and an alternating current was applied at a current density of 2.3 m/min using stainless steel as the counter electrode in a calcium hydroxide bath of 0.3 m/min. When the current was applied for 15 minutes at M/d, a silvery gray-white wood grain pattern was formed on the surface of the treated material.

Thereafter, the material to be treated was subjected to anodizing treatment and coloring treatment in the same manner as in Example 1, and an aluminum material having a clear colored wood grain pattern was obtained. Example
9 Pre-treat aluminum material 606$-T5 by a conventional method,
Sodium carbonate 5 days / phthalic acid 5 days / Yunaka,
Using stainless steel as the counter electrode, the AC current density is 2.0A/
When the current was applied for 15 minutes at d, a silvery gray-white wood grain pattern was formed on the surface of the treated material.

Thereafter, the treated material was subjected to sodium hydroxide solution immersion treatment, anodization treatment, and coloring treatment in the same manner as in Example 1, and an aluminum material having a clear colored wood grain pattern was obtained. Example 10 Aluminum material 606$-T5 was pretreated by a conventional method,
Sodium fluoride was heated for 20 minutes in the bath, and a carbon plate was used as the counter electrode to conduct alternating current at a current density of 1. When electricity was applied for 20 minutes using I/D, a silvery gray-white wood grain pattern was formed on the surface of the treated material.

Claims (1)

[Scope of Claims] 1 (a) The aluminum material is made of sodium orthosilicate, trisodium phosphate, sodium hydrogen phosphate, sodium metaborate, sodium hydroxide, sodium silicate, calcium hydroxide, sodium carbonate, and sodium fluoride. An aqueous solution of one or more alkaline electrolytes selected from the group consisting of, or an aqueous solution to which a barrier-type film-forming electrolyte selected from the group consisting of phthalic acid, boric acid, phosphomolybdic acid, and ammonium tartrate is added as an electrolyte, Electrolytic treatment is performed under conditions in which hydrogen gas is generated on the surface of the aluminum using AC or a power waveform having a similar effect; (b) Hydrogen gas bubbles generated on the surface of the object to be treated during the above electrolysis. (c) After carrying out the above electrolysis until a silvery-gray white wood grain pattern is formed on the surface of the workpiece due to the action of the hydrogen gas bubbles, the workpiece is raised along the surface of the workpiece. anodizing in an electrolytic solution containing an inorganic acid, an organic acid, or both; and (d) placing the anodized product in an inorganic coloring bath or a dye or pigment solution containing a metal salt. A method for surface treatment of aluminum material, characterized by: coloring the surface of an object to be treated by immersing the object.