JPS5919995B2 - 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.

Conventionally, as a method for forming a pattern such as a wood grain pattern on the surface of an aluminum material, there is a method (4) of stamping predetermined score lines on the surface of the aluminum material using a pressure roll or a press mold.

(B) A method of etching the surface of an aluminum material using a photoengraving method to etch the original image.

(0 A method in which the surface of an aluminum material is partially masked with a suitable protective material, and then sprayed with paint, chemically dyed, or colored with an oxide film.

(g) By means such as screen printing or transfer printing,
A method of printing paint or other colored materials onto the surface of aluminum materials.

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 (4) is a method of compressing the workpiece while strongly pressing it with a pair of dies or molds, so it can only be applied to flat aluminum materials. The disadvantage is that it requires a large amount of money to produce the mold. In addition, the etching method of (day), the masking method of (O), and the printing method of [F] not only require time and effort for masking processing and plate making of the wood grain pattern, but also the subsequent secondary processing is extremely troublesome. There are problems with the durability of the coating.Furthermore, all of these methods, including patterned paper pasting methods, require special machinery and equipment, making processing costs very high, especially on aluminum with complex shapes. The drawback was that it could not be used for wood grains, such as extruded shapes for sash.The inventors of the present invention have conducted various research in search of a method for forming wood grain patterns that does not have the drawbacks of the conventional methods described above. A method of forming a silver-gray wood grain pattern on the surface of a treated material by using hydrogen bubbles generated when wood is subjected to AC electrolysis treatment in an aqueous solution of various electrolytes,
and a method of coloring the wood grain pattern part darker than other parts by subjecting the treated object to a colored oxide film forming treatment to clearly express a beautiful decorative pattern on the surface of the treated object. was first invented and applied for a patent (patent application filed in 1973).
0-136485, etc.).

A pattern forming method similar to this was published in the magazine [Alto Hiryo] in 1930.
It is described in the April issue of 1999, pages 9-13. The present invention enables diversification of pattern expression by the electrochemical pattern formation method described above.

First, an overview of the present invention will be described.
b) Water-soluble protein, water-soluble polyester, etc. are added to a bath capable of forming a barrier film consisting of an aqueous solution of a specific acid or an aqueous solution of an alkali metal, alkaline earth metal, or ammonium hydroxide or salt. Using an electrolytic solution containing at least one compound selected from the group consisting of sugars, water-soluble monosaccharides, water-soluble polymer compounds, and alcohols, using alternating current or a power waveform with a similar effect, Electrolytically treating an aluminum material under conditions that generate hydrogen gas (hereinafter referred to as AC electrolytic treatment); (b) causing bubbles of hydrogen gas generated during the above electrolysis to rise along the surface of the object to be treated; and (c) carrying out the electrolysis until a silver-gray grain pattern is formed on the surface of the object to be treated by the action of the hydrogen gas bubbles (hereinafter referred to as the first invention). ), and a method for surface treatment of an aluminum material (hereinafter referred to as the second invention), which comprises subjecting the aluminum material treated by the above method to an optional colored oxide film forming treatment.

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

Specific examples of inorganic and organic acids that can be used as electrolyte components for AC electrolysis include sulfuric acid, phosphoric acid,
Sulfamic acid, boric acid, chromic acid, pyrophosphoric acid, formic acid, acetic acid, propionic acid, butyric acid, oxalic acid, malonic acid, succinic acid, adipic acid, maleic acid, itaconic acid, glycolic acid, gluconic acid, lactic acid, tungstic acid, Selenite, malic acid, tartaric acid, citric acid, benzenesulfonic acid, phenolsulfonic acid, cresolsulfonic acid, thymolsulfonic acid, sulfosalicylic acid, sulfophthalic acid,
Examples include phosphomolybdic acid, and two or more of these may be used in combination. Preferred examples of hydroxides and salts that can be used in combination with the above acids include sodium hydroxide, potassium hydroxide, calcium hydroxide, lithium hydroxide, barium hydroxide, ammonium hydroxide, and silicates thereof. , carbonates, phosphates, sulfates, acetates, borates,
These include oxalates and nitrates.

It is advantageous to use these electrolytes in relatively low concentrations, preferably less than about 35 g/l, to develop the pattern.

In addition, the type and combination of electrolytes used are
Select so that H is 1 to 12 (needless to say,
Even if an acid is used to prepare the electrolytic solution, if the pH ultimately exceeds at least 7, no free acid is present during electrolysis, but a salt or a salt and an alkali hydroxide are present. Therefore, an electrolytic solution having a composition similar to this may be prepared from a salt or a salt and an alkali hydroxide without using an acid.
) Further, in the present invention, preferred specific examples of the auxiliary components such as the water-soluble protein contained in the electrolyte include gelatin and albumin as the water-soluble protein, and starch, textrin, and the like as the water-soluble polysaccharide. Water-soluble monosaccharides such as hemicellulose include various tetroses (e.g. threose), hexoses (e.g. glucose), etc.
Examples of water-soluble polymer compounds include polyvinyl alcohol, alkyd resins, and acrylic resins, and examples of alcohols include glycerin and cyclohexanol.

Aluminum material that has been pretreated by conventional methods such as degreasing and etching is subjected to alternating current electrolysis in an electrolytic solution containing the above electrolyte and auxiliary components under conditions that generate hydrogen gas, and then If the generated hydrogen gas bubbles are allowed to rise along the surface of the object to be treated, a silver-gray wood grain pattern will appear on the surface that extends in the hanging direction (vertical direction) of the object, so electrolysis is not performed at this stage. stop.

Wood grain patterns appear due to electrolysis when hydrogen gas bubbles of various sizes generated during electrolytic treatment rise to the water surface from below while moving slightly from side to side along the surface of the treated object. There is a large difference in electrolyte between the area traced by the bubbles and other areas of the surface of the processed material, and the area through which the bubbles pass has far more pores than other areas. It is thought that this is because a porous film is formed in the area through which the bubbles pass, and a barrier type film is formed in other areas. When the electrolytic solution for this AC electrolytic treatment contains auxiliary components such as water-soluble proteins, the physical and chemical properties such as viscosity of the electrolytic solution change compared to the case where it does not contain this. The manner in which hydrogen bubbles rise during electrolysis changes depending on the degree of electrolysis. Therefore, according to the present invention, the pattern formed on the surface of the workpiece can be varied in various ways by making the wood grain streak pattern shorter or more blurred than in the case of the conventional electrochemical wood grain pattern formation method. It can be enriched. The aluminum material with a pattern formed on its surface according to the first invention as described above can be used for many purposes simply by coating it with a protective film such as transparent paint, but the clarity of the pattern may be poor. If it is insufficient, the method of the second invention may be adopted, which further performs a colored oxide film forming treatment.

In the second invention, the colored oxide film forming treatment performed subsequent to the AC electrolytic treatment can be performed in the same manner as the well-known colored oxide film forming treatment of a general (patternless) aluminum material.

Typical processing methods include the following. (a) The object to be treated after the AC electrolytic treatment is subjected to AC electrolysis in a colored bath to which a metal salt is added.

(b) The object to be treated after the alternating current electrolytic treatment is immersed in a colored bath containing metal salts or a bath containing dyes or pigments.

(c) The object to be treated after the AC electrolytic treatment is subjected to an electrolytic coloring treatment in an electrolytic solution containing an inorganic acid, an organic acid, or a mixture thereof.

(d) The object to be treated after the AC electrolytic treatment is anodized in an electrolytic solution containing an inorganic acid, an organic acid, or a mixture thereof, and then subjected to an AC electrolytic treatment in a colored bath containing a metal salt.

(E) The object to be treated after AC electrolysis treatment is anodized in an electrolytic solution containing an inorganic acid, an organic acid, or a mixture thereof, and then a coloring bath containing a metal salt or a dye or pigment is added. Immerse in a bath.

When this type of colored oxide film formation treatment is applied, the wood grain pattern, which was silvery gray before the treatment, is colored to a significantly sharper tone by the inorganic metal salts, dyes, or pigments in the coloring bath. Appear on the surface of things.

The colored wood grain pattern is created by this coloring treatment because many pores are concentrated in the silvery gray wood grain pattern formed by the AC electrolytic treatment, and metal salts, dyes, This is thought to be due to the fact that coloring components such as pigments are deposited or adhered in a much larger amount than in other areas with a smaller pore distribution. In addition, according to the method of the second invention, while developing a colored wood grain pattern, it also completely eliminates roll marks, scratches, bruises, dice marks, and streaks after anodizing that are found in ordinary processed aluminum materials. be able to.

As mentioned above, the method of the present invention is based on an electrochemical method that naturally generates a wood grain pattern on the surface of an aluminum material and furthermore clearly colors the wood grain portion, and is an improvement on this method. Therefore, compared to the conventional non-electrochemical wood grain pattern formation method, 1. there is no need to create an original pattern of the wood grain pattern, making it extremely simple and easy to express the pattern; 2. Productivity is extremely high because no processing or manual labor is required; 3. Unlike artificial patterns created by traditional methods such as stamping, etching, spraying or baking, and printing, the same pattern does not repeat. from,
Not only does it have many advantages, such as: it produces an extremely natural wood grain pattern that is close to the true wood grain, but it also has many advantages, such as the electrical conditions of AC electrolysis and the type of electrolyte used, compared to the electrochemical method that was the subject of improvement. Another advantage is that various patterns can be easily formed, including special patterns that would be difficult to form simply by changing the density or the like.

Therefore, the surface treatment method of the present invention can improve product value by imparting wood grain patterns to aluminum sashes, fittings, and panels for buildings, as well as vehicles, household appliances, and decorative aluminum materials. When applied to the treatment of various aluminum materials for which such effects are expected, extremely remarkable effects can be achieved.

The present invention will be explained below with reference to Examples.

Example 1 An aluminum 6063S-T5 profile was pretreated by a conventional method, and boric acid 5g/11 sodium metaborate 30g/1
When AC current was applied at 30 V for 10 minutes using stainless steel as the counter electrode in a bath containing 1 gelatin and 25 g/l, a silver-gray wood grain pattern was formed on the surface of the profile.

This shape was then subjected to AC electrolysis treatment in an inorganic coloring bath containing stannous sulfate, and finally coated with a transparent resin paint, resulting in a beautiful aluminum shape with only the wood grains colored. It was done. For comparison, an aluminum material was treated in the same manner as in the above example except that gelatin was not added to the electrolyte solution in AC electrolytic treatment, and the pattern formed was linear, which was slightly different from that in the above example. There was little change.

Example 2 An aluminum 6063S-T5 profile was pretreated by a conventional method, and subjected to alternating current at 35 V for 10 minutes using stainless steel as the counter electrode in a bath containing 15 g of boric acid/1 g of sodium hydroxide/25 g/l of glucose. When electricity was applied, a silver-gray wood grain pattern was formed on the surface of the profile.

This profile was then washed in an inorganic coloring bath containing stannous sulfate (
70°C) and finally dip-coated with a transparent resin paint, a beautiful aluminum shape with only the wood grains colored was obtained. For comparison, an aluminum material was treated in the same manner as in the above example except that glucose was not added to the electrolyte solution of AC electrolytic treatment.The pattern formed was a repeating linear pattern, and compared to that in the above example. The natural wood grain texture was slightly inferior.

Example 3 An aluminum 6063S-T5 profile was pretreated by a conventional method, and energized at 30 V AC for 10 minutes using a carbon plate as a counter electrode in a bath containing 5 g of boric acid, 14 g of 11 sodium sulfate, and 30 g/l of starch. As a result, a silver-gray wood grain pattern was formed on the surface of the profile.

This profile was then anodized for 40 minutes at 30 V DC in a bath containing 50 g/l of sulfosalicylic acid/50 g/l of 11 maleic acid, and then electrostatically coated, resulting in a bronze-colored pattern. A beautiful aluminum profile was obtained.
For comparison, an aluminum material was treated in the same manner as in the above example except that no starch was added to the electrolyte in the AC electrolytic treatment.The pattern formed was somewhat uniform, and compared to the pattern in the above example, the wood grain It was unnatural.

Example 4 An aluminum 6063S-T5 profile was pretreated in a conventional manner and treated with sulfuric acid (5 g/l) and sodium carbonate (11 g/l).
l) When alternating current was applied at 30 V for 15 minutes using a carbon plate as a counter electrode in a bath containing 30 g/l of glycerin, a silver-gray wood grain pattern was formed on the surface of the profile.

Next, this shape was treated with a sodium carbonate aqueous solution (50 g/l)
40℃) for 2 minutes, washed with water, and then soaked in a sulfuric acid bath for 10μ
After applying an anodized film and washing with water, it was subjected to alternating current electrolysis treatment in an inorganic coloring bath containing nickel sulfate, and finally electrocoated, resulting in a beautiful aluminum shape with a bronze-colored wood grain pattern. Obtained. For comparison, an aluminum material was treated in the same manner as in the above example except that glycerin was not added to the electrolyte in the AC electrolytic treatment. Compared to other examples, it had a strong feel that was different from natural wood.

Example 5 An aluminum 1050P-Hl4 plate material was pretreated by a conventional method and treated with 0.0% phosphoric acid. ! When AC current was applied at 15 V for 15 minutes using carbon acid as the counter electrode in a bath containing 0.2 mO1z of sodium metasilicate (MOl/l) and 20 g/l of glucose, a silver-gray grain pattern was formed on the surface.

Next, this board was coated with a 10μ anodic oxide film in a sulfuric acid bath, then immersed in an inorganic coloring bath (60°C) containing ferric ammonium oxalate, and finally treated with boiling water. An aluminum plate material with a beautiful pattern was obtained. For comparison, an aluminum material was treated in the same manner as in the above example except that glucose was not added to the electrolyte solution in the AC electrolytic treatment. Compared to natural wood, there were fewer changes typical of natural wood.

Claims (1)

[Claims] 1 (a) Sulfuric acid, phosphoric acid, sulfamic acid, boric acid, chromic acid, pyrophosphoric acid, formic acid, acetic acid, propionic acid, butyric acid, oxalic acid, malonic acid, succinic acid, adipic acid, maleic acid , itaconic acid, glycolic acid, gluconic acid, lactic acid,
One type selected from the group consisting of tungstic acid, selenite, malic acid, tartaric acid, citric acid, benzelsulfonic acid, phenolsulfonic acid, cresolsulfonic acid, thymolsulfonic acid, sulfosalicylic acid, sulfophthalic acid, and phosphomolybdic acid. Water-soluble proteins, water-soluble polysaccharides, water-soluble monosaccharides, and water-soluble polymers are added to a bath consisting of an aqueous solution of the above acids or a hydroxide or salt of an alkali metal, alkaline earth metal, or ammonium. Using an electrolytic solution containing at least one compound selected from the group consisting of compounds and alcohols, the aluminum material is heated under conditions where hydrogen gas is generated by alternating current or a power waveform with a similar effect. (b) During the above electrolysis, hydrogen gas bubbles generated rise along the surface of the object to be treated; and (c) A silvery gray color appears on the surface of the object due to the action of the hydrogen gas bubbles. A method for surface treatment of aluminum material, characterized in that the above electrolysis is performed until a wood grain pattern is formed. 2 (a) Sulfuric acid, phosphoric acid, sulfamic acid, boric acid, chromic acid, pyrophosphoric acid, formic acid, acetic acid, propionic acid, butyric acid, oxalic acid, malonic acid, succinic acid, adipic acid, maleic acid, itaconic acid, glycolic acid , gluconic acid, lactic acid,
One or more selected from the group consisting of tungstic acid, selenite, malic acid, tartaric acid, citric acid, benzenesulfonic acid, phenolsulfonic acid, cresolsulfonic acid, thymolsulfonic acid, sulfosalicylic acid, sulfophthalic acid, and phosphomolybdic acid. Water-soluble proteins, water-soluble polysaccharides, water-soluble monosaccharides, and water-soluble polymer compounds are added to a bath consisting of an aqueous solution of an acid or a hydroxide or salt of an alkali metal, alkaline earth metal, or ammonium. Aluminum material is electrolyzed under conditions where hydrogen gas is generated using an electrolytic solution containing at least one compound selected from the group consisting of alcohols and alcohols, using alternating current or a power waveform with a similar effect. (b) During the above electrolysis, hydrogen gas bubbles generated rise along the surface of the object to be treated; (c) Due to the action of the hydrogen gas bubbles, a silver-gray wood grain pattern is formed on the surface of the object to be treated. 1. A method for surface treatment of an aluminum material, comprising: carrying out the above electrolysis until the above electrolytically treated aluminum material is formed; and (d) subjecting the aluminum material after the above electrolytic treatment to a colored oxidation wave film forming treatment.