JPS6321760B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention involves depositing a metal oxide into the fine pores of the anodic oxide film, partially attaching a masking substance to the colored aluminum surface, and lightening or decolorizing the areas to which the masking substance is not attached. In particular, the present invention relates to a surface treatment method for generating a pattern based on a difference in color shading or tone between areas to which a masking substance is attached and areas to which a masking substance is not attached. In this specification, aluminum is a general term for aluminum and aluminum alloys. Conventionally, when electrolytic coloring is performed using a bath containing a metal oxyacid or its salt, or a bath containing a metal salt other than a metal oxyacid salt and hydrogen peroxide as a coloring bath, metal is formed in the micropores of the anodic oxide film. On the other hand, when electrolytic coloring is performed using a bath that contains metal salts other than metal oxyacids and does not contain metal oxyacids or hydrogen peroxide, elemental metals are deposited in the micropores of the anodic oxide film. It is speculated that it precipitates. In the latter case, in the case of aluminum colored by precipitating a single metal in the fine pores of the anodic oxide film, after partially attaching a masking substance to the surface, inorganic acid, organic acid, or It is known that areas to which masking substances are not attached can be decolorized by immersing them in a bath containing salt or electrolytically treating them in the bath (Japanese Patent Laid-Open No.
57-149491). However, when partially decolorizing colored aluminum formed by precipitating metal oxides in the micropores of the anodic oxide film, the above-mentioned known decolorizing method is applied to partially mask the colored aluminum, and then the inorganic Even when immersed in a bath containing acids, organic acids, or their salts, it was difficult to decolor or even lighten the color. Furthermore, aluminum that has been colored due to the precipitation of metal oxides can be decolorized by electrolytic treatment in a bath containing the above-mentioned inorganic acids, organic acids, or their salts, but the electrolytic treatment equipment is not suitable. This method is expensive and requires electrical energy for decolorization or lightening, and has the disadvantage that patterned aluminum products cannot be provided at low cost. The method of the present invention was developed in view of the above-mentioned drawbacks, and a masking material can be created by simply immersing aluminum, which has been colored by precipitating metal oxides into the micropores of the anodic oxide film, in an aqueous solution without electrolytic treatment. This is a unique ingenuity designed to decolorize or evenly lighten the non-adherent areas of the skin. That is, in the method of the present invention, a masking substance is deposited in an appropriate pattern on the surface of aluminum on which metal oxide has been precipitated in the fine pores of the anodic oxide film, and then the aluminum with the masking substance still attached is deposited on the surface of the aluminum. It is characterized in that a pattern is created by immersing it in an aqueous solution containing a substance that has a reducing effect to decolor or lighten the area to which the masking substance is not attached. To further explain the present invention in detail, first, the conventional method for forming an anodic oxide film on the surface of aluminum is to pre-treat aluminum, such as degreasing, etching, and removing smut, by treating it with sulfuric acid and oxalic acid. Electrolysis is carried out in a bath that produces a porous oxide film, such as sulfuric acid and oxalic acid mixed acid, using a current waveform having an equivalent effect, such as direct current electrolysis, alternating current electrolysis, or alternating current vertical electrolysis. Next, an electrolytic coloring treatment is performed, but prior to this, an electrolytic treatment that changes the characteristics of the anodic oxide film may be performed. Treatment baths for this purpose include orthophosphoric acid, pyrophosphoric acid, phosphorous acid, chromic acid, sulfuric acid,
It is mainly composed of high concentration sulfuric acid of 40V/V% or more or one or more inorganic acids of these salts, and also contains malic acid, gluconic acid, maleic acid, citric acid, malonic acid, Tartaric acid, cresol sulfonic acid, sulfophthalic acid, sulfosalicylic acid,
Gallic acid, benzoic acid, phthalic acid, carbolic acid, etc.
A bath containing one or more organic acids or salts thereof containing an OH group or a -COOH group is used. Moreover, the above-mentioned inorganic acids and organic acids can be used as a mixture as appropriate. As the current waveform, an alternating current or a similar waveform in which positive and negative polarities are alternately changed, a direct current, or an AC/DC superimposed waveform is used. The treatment voltage is preferably 5 to 50V, and the treatment time is 1 to 10 minutes to obtain a sufficient effect. Due to this electrolytic treatment, the structure of the micropores in the anodic oxide film becomes complicated and different from that of the conventional method, and the characteristics of the anodic oxide film are changed to a state where the pores are difficult to be sealed. As mentioned above, electrolytic coloring treatment is performed after anodizing treatment or further electrolytic treatment that changes the characteristics of the anodic oxide film.
The electrolytic coloring treatment of the method of the present invention is a treatment in which metal oxides are precipitated into the micropores of the anodic oxide film, and the following two baths can be mentioned as main baths for this purpose. A bath containing metal oxyacids or their salts such as molybdenum, selenium, manganese, vanadium, tungsten, and tellurium. scandium, titanium, chromium, manganese,
A bath containing metal salts such as iron, cobalt, nickel, copper, and zinc and hydrogen peroxide. By performing electrolytic treatment in the above coloring bath using an appropriate current waveform such as DC cathode electrolysis, AC electrolysis, AC/DC superimposed electrolysis, or incompletely rectified waveform, metal oxides are precipitated in the micropores of the anodic oxide film and colored. Aluminum is obtained. After this, a masking substance is attached to the surface of the aluminum, but at this time the surface of the aluminum needs to be dry, and hot water washing is preferably performed to accelerate drying and improve production efficiency. If an anodic oxide film or a colored anodic oxide film obtained by a conventional method is simply washed with hot water, it becomes sealed and loses its activity as an anodized film, making subsequent decolorization or lightening difficult. However, if electrolytic treatment is applied to structurally change the micropores of the anodic oxide film as described above, it is possible to change the characteristics of the anodic oxide film to a state where it is difficult to seal, and there is no sealing effect. Can be washed with hot water. Although it is preferable to use pure water as the condition for hot water washing, it is not limited to this, and water containing a surfactant near neutrality or water containing other chemicals as appropriate can also be used. The processing time that enables hot water washing without sealing is 1 to 30 minutes at 50 to 90℃, 90 to 90℃.
The temperature is preferably 1 to 10 minutes at 100°C, and can be freely selected within this range. When the colored anodic oxide film whose properties have been changed as described above is washed with hot water, the colored anodic oxide film is not sealed and quickly dries after being pulled out of the treatment tank for the next process. It is possible to move on to a process of applying a masking substance for patterning. Masking substances include hydrophobic oily substances such as fretate, acetate, ethylene glycol, and higher fatty acid esters, and transparent synthetic resins such as acrylic resins, urethane resins, epoxy resins, and alkyd resins with high-boiling organic solvents added as diluents. Using a commercially available quick-drying offset ink or gravure ink containing a resin or a low-boiling organic solvent as a diluent, these masking substances are directly applied to the aluminum by conventional printing methods such as screen printing and gravure offset printing. It may be attached to the surface in an appropriate pattern. In addition, for aluminum that has a very complicated uneven surface that makes it difficult to directly attach a masking substance to the aluminum surface by printing, the masking substance can be the above-mentioned hydrophobic oil-based substance or synthetic resin with a high boiling point organic solvent as a diluent. These masking substances may be applied to the aluminum surface using the added transparent resin in the following manner. That is, a thin film printed with the above-mentioned masking material in an appropriate design pattern is floated on the liquid surface with the printed side facing up, and then the aluminum is submerged in the liquid while pressing the above-mentioned printed surface, thereby utilizing liquid pressure. The thin film is applied over the entire surface of the aluminum, thereby causing the masking material on the printed surface to adhere to the surface of the aluminum. In this method, after the masking substance is attached to the surface of the aluminum, it is necessary to remove the thin film using various means such as hot water washing. After the patterned masking substance is adhered to the surface of the aluminum in this way, a dipping treatment is performed to decolor or lighten the color. The treatment bath for this purpose is hydrazine sulfate,
An aqueous solution containing one or more substances having a reducing action such as hydroxylamine sulfate, hydroxylamine hydrochloride, stannous chloride, sodium thiosulfate, sodium hydrogen sulfite, potassium hydrogen sulfite, potassium sulfide, and sodium sulfite is used. . In addition, in order to stabilize the above-mentioned reducing substance, inorganic acids such as sulfuric acid, hydrochloric acid, phosphoric acid, pyrophosphoric acid, phosphorous acid, orthophosphoric acid, and organic acids containing -COOH and -OH groups are added to the aqueous solution. acid 1
A species or two or more species may be added. The temperature of the treatment bath can be appropriately selected depending on the desired color tone of the masking substance-free area, but is preferably 10 to 50°C. If the temperature is below 10℃, the decolorizing effect will be insufficient, and if the temperature exceeds 50℃, the above-mentioned reducing substances are often acidic.
Chemical dissolution of the film becomes intense, making it impractical. Furthermore, the treatment time can be appropriately selected depending on the desired color tone, but is preferably 1 to 15 minutes.
If the time is less than 1 minute, a sufficient decolorizing effect cannot be obtained;
Since the color can be completely decolored in about a minute, further immersion is not preferable because it is a waste of time and the chemical dissolution of the film progresses. When aluminum is immersed in the above treatment bath,
Metal oxides precipitated in the micropores of the anodic oxide film in areas where the masking substance is not attached are gradually eluted, becoming lighter in color, and eventually completely eluted and decolored. Generates a pattern based on the difference between the color of the masking substance-attached area obtained by coloring treatment or the color of the masking substance such as offset ink or gravure ink, and the color of the bleached or lightened masking substance-unattached area. It is possible. The aluminum patterned as described above may be further coated. In the method of the present invention, as described above, the aluminum whose masking substance-unattached portions have been bleached or lightened can be further subjected to a second coloring treatment while the masking substance is still attached or after the masking substance has been removed. In the second case of the method of the present invention, in which coloring is performed with the masking substance attached, conventionally known electrolytic coloring, electrolytic coloring, or dyeing can be appropriately employed, and metal oxidation is applied to the fine pores of the anodic oxide film. The color of the masking substance attached area obtained by electrolytic coloring treatment to deposit a substance, or the color of a colored masking substance such as offset ink or gravure ink, and the masking substance obtained by the above secondary coloring treatment. A pattern is generated based on the difference in color of the non-attached portion. The third method of the present invention is to remove the masking substance prior to the above-mentioned secondary coloring treatment, and for this purpose, the aluminum with the masking substance attached after decolorization or lightening is treated with ethyl acetate. , toluene, alcohols, ketones,
The masking substance may be removed by immersing it in various solvents such as halogenated hydrocarbon solvents such as trichlene. In this case, as the coloring treatment, electrolytic coloring treatment or electrolytic coloring treatment can be applied. For example, when performing the secondary electrolytic coloring treatment, the areas where metal oxides have already been precipitated in the micropores of the anodic oxide film (masking Almost no metal or metal oxide is precipitated on areas (to which the substance had adhered), and precipitation occurs concentrated in bleached or lightened areas (areas to which no masking substance had adhered); Even when electrolytic coloring treatment is applied, the area in question develops color intensively, and the pattern is based on the difference in color between the area where metal oxide has already been deposited and the area where metal or metal oxide has newly precipitated or developed color. will be generated. This is because, even when electricity is applied, the metal oxides precipitated in the micropores of the anodic oxide film hardly conduct electricity. This is because the current is concentrated in areas where there is no or has decreased, and new precipitation or coloring occurs in these areas. As mentioned above, in the third case of the method of the present invention, new precipitation or coloring occurs in areas where metal oxides have already precipitated and colored, and a composite color does not result. The part that is
The difference in color between areas where metal or metal oxide has newly precipitated or developed color becomes clear, and a sharp and vivid pattern can be expressed. As described above, the method of the present invention involves attaching a masking substance in an appropriate pattern to colored aluminum, which is made by depositing metal oxides in the micropores of an anodic oxide film, and then simply immersion treatment without electrolytic treatment. Since the masking substance-unattached portions are simply decolored or lightened, equipment costs and electricity costs for electrolytic treatment are unnecessary, and patterned aluminum products can be provided at low cost. In addition, if the color is to be lightened rather than completely bleached, if the method uses electrolytic treatment, it is necessary to strictly control the concentration and temperature of the treatment bath as well as the electrolytic voltage, etc., but with the method of the present invention, If there is, there is no need to manage the electrolytic voltage, and management becomes easy. Examples of the method of the present invention will be described below.

[Example 1] An extruded aluminum alloy A6063S profile was degreased by immersing it in 10wt% nitric acid at a bath temperature of 20℃ for 5 minutes, and then etching treatment was performed by immersing it in a 5wt% sodium hydroxide aqueous solution at 50℃ for 8 minutes. Then, the smut was removed by immersing it in 10 wt% nitric acid at a bath temperature of 20°C. This extruded shape was anodized for 30 minutes in a bath of 150 g of sulfuric acid at a bath temperature of 20°C and a current density of 1 A/dm ² , followed by 150 g of phosphorous acid/
oxalic acid 15g/in a bath, connect the extruded shape to the anode,
Electrolytic treatment was performed to change the characteristics of the anodized film for 1 minute at a bath temperature of 20°C and DC 20V. Next, the extruded shape was connected to the cathode in a bath of 20 g of manganese sulfate/10 ml of hydrogen peroxide solution, and the bath temperature was 15
When electrolytically colored for 1 minute at 30V DC at ℃,
A uniform gold colored film was formed on the surface of the extruded shape. This extruded shape was washed with pure water at 70°C for 10 minutes, and then the surface of the film was dried. Next, a polyvinyl alcohol thin film gravure-printed with a wood grain pattern made of a transparent resin consisting of a mixture of alkyd resin, butyl carbitol acetate, and dibutyl phthalate was floated on the water surface with the printed side facing up, and placed on the extruded shape. The thin film was brought into close contact using water pressure, and the masking material in the wood grain pattern was adhered to the extruded shape, and then the thin film was dissolved and removed using a hot water shower at 40°C. After that, when this extruded shape is immersed in an aqueous solution of 35 g of hydroxylamine sulfate for 4 minutes at a bath temperature of 30°C, the areas to which the masking substance is not attached are bleached to a silver color, and a gold color with a silver base is formed. A wood grain pattern was uniformly formed on the surface of the extruded shape. When this extruded shape was painted with a light beige translucent clear paint, a beautiful white wood-like wood grain was created on the aluminum surface.

[Example 2] After subjecting an aluminum plate A1100P to the same pretreatment and anodic oxidation treatment as in Example 1, sulfuric acid amide 50
Connected to the anode in a bath with a temperature of 20℃,
Electrolytic treatment was performed for 3 minutes at DC20V to change the characteristics of the anodic oxide film. Next, this aluminum plate was placed in a bath containing 10 g of potassium permanganate and 10 g of sulfuric acid at a bath temperature of 20 g.
When electrolyzed for 3 minutes at ℃ and AC15V, a dark yellow colored anodic oxide film was formed. This aluminum plate was washed with pure water at 65°C for 15 minutes, and then the surface of the film was dried. An epoxy resin-based brown screen ink serving as a masking substance was applied to this aluminum plate in a wood grain pattern using screen printing, and then dried at 100°C for 5 minutes.
Next, this aluminum plate was treated with 10 g of stannous chloride/
When the sample was immersed in 100 g of hydrochloric acid/bath for 1 minute at a bath temperature of 20°C, the area to which the masking substance was not attached became pale gold in color. When this aluminum plate was painted with acrylic clear paint, a wood grain pattern consisting of pale gold and brown was created on the aluminum plate.

[Example 3] Example 1 for aluminum alloy A6063S extruded shape
After performing the same pretreatment and anodic oxidation treatment,
It was connected to an anode in a bath of 150 g of phosphorous acid and 20 g of malonic acid, and subjected to electrolytic treatment for 4 minutes at a bath temperature of 25° C. and a DC of 17 V to change the characteristics of the anodic oxide film. Next, the extruded shape was treated with 30 g of selenite/sulfuric acid.
When electrolytic coloring was carried out in 14 g/bath at a bath temperature of 20° C. and AC 16 V for 3 minutes, a uniform dark golden colored film was formed on the surface of the extruded shape. This extruded shape was washed with pure water at 74°C for 5 minutes, and then hot air was blown at 50°C for 10 minutes to dry the surface of the film. This extruded section was then gravure offset printed with a wood grain pattern using a brown commercially available gravure ink containing a maleic acid resin as a vehicle as a masking substance. When this extruded shape is immersed in 10 g of sodium thiosulfate for 2 minutes at a bath temperature of 40°C, the non-inked areas lighten to a lemon gold color, and a bright brown wood grain pattern with a lemon gold base appears. It was generated uniformly on the surface of the aluminum extruded shape.

[Example 4] Example 1 for aluminum alloy A6063S extruded shape
After performing the same pretreatment and anodic oxidation treatment,
Connected to the cathode in a bath containing 20 g of cobalt sulfate and 25 ml of hydrogen peroxide, electrolytic coloring treatment was performed for 50 seconds at a bath temperature of 20°C and DC 33V to create a uniform yellow colored film on the surface of the extruded shape. I let it happen. This extruded shape was heated at 65°C using industrial well water with a pH of 7.
After washing with hot water for 3 minutes, warm air at 60°C was blown for 5 minutes to dry the surface of the film. Next, using a commercially available dark brown gravure ink containing a rosin-modified phenolic resin as a vehicle as a masking substance, a woodgrain pattern was gravure offset printed on the extruded shape. When this aluminum extruded shape was immersed in a bath containing 50 g of hydroxylamine hydrochloride for 2 minutes at a bath temperature of 30°C, the non-inked areas became pale yellow.
A dark brown wood grain pattern with a pale yellow base was uniformly formed on the surface of the aluminum profile.

[Example 5] Example 1 for aluminum alloy A6063S extruded shape
After performing the same pretreatment and anodic oxidation treatment,
100g of pyrophosphoric acid/50g of malic acid/connect the extruded shape to the anode in a bath, bath temperature 20℃, DC 20V
Electrolytic treatment was performed for 2 minutes to change the properties of the anodic oxide film. Next, the extruded shape was treated with sodium molybdate 30g/, sulfuric acid 20g/, boric acid 30g/
When electrolytic coloring treatment was carried out for 4 minutes at a bath temperature of 22°C and AC 12V, a uniform beige colored film was formed on the surface of the extruded shape. This extruded shape was heated at 75°C using industrial well water with a pH of 7.
After washing with hot water for 10 minutes, the surface of the film was dried. Next, a thin film of sodium polyacrylate that had been gravure printed with a wood grain pattern made of a transparent resin made by mixing butyl cellosolve, ethyl alcohol, polyvinyl butyral, and dibutyl phthalate was floated on a water surface with the printed side facing up, and the above-mentioned extrusion process was carried out. The thin film was brought into close contact with the shape using water pressure, and the masking substance of the wood grain pattern was adhered to the extruded shape, and then the thin film was dissolved and removed using a hot water shower at 35°C. After that, this extruded shape was heated to 30% potassium bisulfite.
g/, 2 g of sulfuric acid/ When immersed in a bath at a bath temperature of 25°C for 10 minutes, the areas to which the masking substance is not attached will be bleached to a silver color, and a beige-colored wood grain pattern with a silver base will be uniformly distributed on the extruded shape surface. generated.

[Example 6] After subjecting an aluminum plate A1200P to the same pretreatment and anodizing treatment as in Example 1, chromic acid 100
Connected to the anode in a bath with a temperature of 20℃,
Electrolytic treatment was performed for 4 minutes at DC20V to change the characteristics of the anodic oxide film. This aluminum plate was then treated with 30% ferrous sulfate.
When connected to a cathode in a bath containing 20 ml of hydrogen peroxide solution and electrolytic coloring treatment for 1 minute at a bath temperature of 20° C. and a DC of 40 V, a uniform deep yellow colored film was formed on the surface of the extruded shape. After drying this aluminum plate in an atmosphere of 100°C for 10 minutes, an acrylic paint as a masking substance was spray-painted through a polka-dot masking pattern. Next, this aluminum plate was treated with 5 g of sulfuric acid/
When immersed in 20g of hydrazine sulfate/bath for 3 minutes at a bath temperature of 30°C, the area to which the masking substance is not attached becomes pale yellow, and a dark yellow polka dot pattern with a pale yellow base is uniformly formed on the surface of the aluminum plate. did.

[Example 7] Example 1 for aluminum alloy A6063S extruded shape
After performing the same pretreatment and anodizing treatment, electrolytic coloring is performed in a bath of 30 g of sodium selenite and 20 g of sulfuric acid at a bath temperature of 20°C and 15 VAC for 3 minutes, resulting in a uniform coloring on the surface of the extruded shape. A lemon gold colored film was formed. After drying this extruded shape, a polyvinyl alcohol thin film screen-printed with a wood grain pattern using a transparent resin made of thermosetting acrylic resin, toluene, and butyl carbitol is floated on the water surface with the printed side facing up. , the thin film was adhered to the extruded shape using water pressure, and the masking substance of the wood grain pattern was attached to the extruded shape, and then heated at 40°C.
The thin film was dissolved and removed using a warm water shower. After that, it was dried at 80℃ for 5 minutes, and then the extruded shape was mixed with 5 g of potassium sulfide and 5 g of sulfuric acid.
When immersed in a bath for 2 minutes at a bath temperature of 25°C, the area to which the masking substance is not attached becomes pale orange.
The material changed color, and a lemon gold-colored wood grain pattern with a pale orange base was uniformly formed on the surface of the extruded shape. When this extruded shape was coated with a pale white matte translucent clear paint, a beautiful white wood-like wood grain pattern was uniformly formed on the aluminum surface.

[Example 8] Example 1 for aluminum alloy A6063S extruded shape
After performing the same pretreatment and anodizing treatment as above, the extruded shape was connected to the anode in a bath of 150 g of phosphorous acid and 15 g of oxalic acid, and the characteristics of the anodized film were evaluated for 1 minute at a bath temperature of 20°C and 20 V DC. Electrolytic treatment was performed to change the Next, the extruded shape was connected to the cathode in a bath of 20 g of manganese sulfate/10 ml of hydrogen peroxide solution, and the bath temperature was 15
When electrolytically colored for 1 minute at 30V DC at ℃,
A uniform gold colored film was formed on the surface of the extruded shape. This extruded shape was washed with pure water at 70°C for 10 minutes, and then the surface of the film was dried. Next, a polyvinyl alcohol thin film gravure-printed with a wood grain pattern made of a transparent resin consisting of a mixture of alkyd resin, butyl carbitol acetate, and dibutyl phthalate was floated on the water surface with the printed side facing up, and placed on the extruded shape. The thin film was brought into close contact using water pressure, and the masking material in the wood grain pattern was adhered to the extruded shape, and then the thin film was dissolved and removed using a hot water shower at 40°C. After that, when this extruded shape is immersed in an aqueous solution of 35 g of hydroxylamine sulfate for 4 minutes at a bath temperature of 30°C, the areas to which the masking substance is not attached are bleached to a silver color, and a gold color with a silver base is formed. A wood grain pattern was uniformly formed on the surface of the extruded shape. The extruded shape with this masking substance still attached was placed in a bath of 10 g of stannous sulfate, 10 g of sulfuric acid, and 10 g of sulfosalicylic acid at a bath temperature of 20°C and an AC of 20 V.
When the secondary electrolytic coloring treatment was performed for 2 minutes at , the areas to which the masking substance was not attached were colored bronze, and a wood grain pattern of two colors, bronze and gold, was formed on the surface of the extruded shape.

[Example 9] Example 1 for aluminum alloy A6063S extruded shape
After performing the same pretreatment and anodizing treatment, electrolytic coloring is performed in a bath of 30 g of sodium selenite and 20 g of sulfuric acid at a bath temperature of 20°C and 15 VAC for 3 minutes, resulting in a uniform coating on the surface of the extruded shape. A lemon gold colored film was formed. After drying this extruded shape, a thin film of polyvinyl alcohol screen-printed with a wood grain pattern on a transparent resin consisting of thermosetting acrylic resin, toluene, and butyl carbitol was placed on top of the water surface with the printed side facing up. After floating the thin film on the extruded shape using water pressure and attaching the masking substance of the wood grain pattern to the extruded shape,
The thin film was dissolved and removed using a hot water shower at ℃. After that, it was dried at 80℃ for 5 minutes, and then the extruded shape was mixed with 5 g of potassium sulfide and 5 g of sulfuric acid.
When the sample was immersed in a bath for 2 minutes at a bath temperature of 25°C, the area to which the masking substance was not attached became pale orange, and a lemon-gold wood grain pattern with a pale orange base was formed on the surface of the extruded shape. After immersing this extruded shape in trichlene to remove the masking substance, 30 g of nickel sulfate/
, Boric acid 30g/connected to the cathode in the bath, bath temperature 20
When a secondary electrolytic coloring treatment was performed for 1 minute at ℃ and 25V DC, the pale orange color was colored into a pale bronze color, and a lemon gold-colored wood grain pattern with a pale bronze color as a base was formed on the surface of the extruded shape.

Claims (1)

[Claims] 1. After electrolytically coloring aluminum on which an anodic oxide film has been formed by a conventional method to precipitate metal oxides into the micropores of the anodic oxide film, a masking substance is applied to the surface of the aluminum. The pattern is created by attaching the masking substance in an appropriate pattern, and then immersing the aluminum with the masking substance attached in an aqueous solution containing a substance that has a reducing effect to decolor or lighten the area where the masking substance is not attached. A patterned surface treatment method for aluminum. 2. The method for patterning aluminum according to claim 1, wherein the electrolytic coloring treatment is performed in a bath containing a metal oxyacid or a salt thereof. 3. The method for patterning aluminum according to claim 1, wherein the electrolytic coloring treatment is carried out in a bath containing a metal salt and a hydrogen peroxide solution. 4 After electrolytically coloring aluminum on which an anodic oxide film has been formed by a conventional method to precipitate metal oxides into the micropores of the anodic oxide film, a masking substance is applied to the surface of this aluminum in an appropriate pattern. Then, the aluminum with the masking substance attached was immersed in an aqueous solution containing a substance with a reducing effect to decolor or lighten the area where the masking substance was not attached, and then the masking substance was attached. A patterned surface treatment method for aluminum, characterized in that a pattern is generated by coloring raw aluminum. 5 After electrolytically coloring aluminum on which an anodic oxide film has been formed by a conventional method to precipitate metal oxides into the micropores of the anodic oxide film, a masking substance is applied to the surface of this aluminum in an appropriate pattern. Then, the aluminum with the masking substance attached is immersed in an aqueous solution containing a substance having a reducing action to decolor or lighten the area where the masking substance is not attached, and then, the masking substance is removed, A patterned surface treatment method for aluminum, characterized in that the aluminum is then subjected to an electrolytic coloring treatment or an electrolytic coloring treatment to generate a pattern.