JPS6025517B2 - Patterned surface treatment method for aluminum - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a surface treatment method for freely creating various patterns on the surface of aluminum.

In this specification, aluminum is a general term for aluminum and aluminum alloys.

Conventionally, various methods have been proposed for creating patterns on the surface of aluminum used for lotuses, which have a complicated cross-sectional shape, such as immersing the aluminum before anodizing treatment in a certain liquid and energizing it. In this method, hydrogen gas generated on the surface of aluminum by current treatment creates an upward locus on the surface of the aluminum.

However, the generation of hydrogen gas during the energization process is not always constant and is extremely irregular, making it impossible to produce a consistent and regular pattern on the surface of aluminum, and also making it impossible to reproduce the same pattern. It has some inconveniences. In addition, since the patterns created by this method depend exclusively on the upward trajectory of hydrogen gas, only monotonous line patterns or straight-grained patterns can be obtained, and it is not possible to create patterns that are suitable for the exterior design depending on the use of aluminum. It has disadvantages that cannot be obtained.

On the other hand, there is nothing better than a general printing method when trying to generate a free design pattern, but it has a problem that it cannot be applied to aluminum for building materials, which has a complicated cross-sectional shape.

Therefore, the present invention provides a patterned surface treatment method that can generate not only a monotonous edge pattern but also a free design pattern similar to the printing method even on aluminum for building materials having a complicated cross-sectional shape. For the purpose of
It is a product of unique ingenuity.

That is, in the method of the present invention, aluminum having an anodic oxide film formed thereon by a conventional method is treated with an organic acid containing -OH group or one COO group, orthophosphoric acid, pyrophosphoric acid, orthophosphoric acid, orthophosphoric acid, pyrophosphoric acid, phosphorous acid, chromic acid,
Alternating current or similar waveform current or direct current with alternating positive and negative polarities in a chamber containing sulfuric acid amide, high concentration sulfuric acid of 40 V/V% or more, or one or more of these salts. Voltage 5-50 using anode or AC/DC superimposed current
Electrolytic treatment is performed with V for more than 1 minute, followed by hot water washing treatment, and substances that inhibit or promote electrolytic coloring in the subsequent process are adhered to the dried aluminum surface in an appropriate pattern. Then, by electrolytically coloring the aluminum to which the inhibitor or promoter is attached, a pattern is created based on the difference between the area to which the inhibitor or promoter is attached and the area to which it is not attached. It is characterized by:

To further explain the method of 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, cleaning, etching, and removing smut, by subjecting it to sulfuric acid, oxidation It is an electrolytic treatment using DC electrolysis, AC electrolysis, AC/DC superimposed electrolysis, or other current waveforms having equivalent effects in a bath that produces a porous oxide film, such as sulfuric acid/oxoacid mixed acid.

At this time, it is permissible to involve color development. Then, the aluminum anodic oxide film produced in this way is further electrolytically treated to change the properties of the anodic oxide film, and the change in properties includes complex changes in the structure of the micropores, etc. It is.

Treatments for this purpose include chromic acid, orthophosphoric acid,
It is mainly composed of one or more inorganic acids among pyrophosphoric acid, phosphorous acid, sulfuric acid amide, high concentration sulfuric acid of 40V/V% or more, or their salts, and also malic acid, gluconic acid. , maleic acid, citric acid, malonic acid, tartaric acid, cresolsulfonic acid, sulfophthalic acid, sulfosalicylic acid, gallic acid, benzoic acid, phthalic acid, carbolic acid, etc.
A case mainly consisting of one or more organic acids or salts thereof containing an H group or a -COO group is used.

Moreover, the above-mentioned inorganic acids and organic acids can be used in an appropriate mixture. As the current waveform, an alternating current or a similar waveform in which positive and negative polarities are alternately changed, a direct current anode, or an AC/DC superimposed current is used.

The processing voltage is 5 to 50V and the processing time is 1 minute or more. If the treatment time is less than 1 minute, the characteristics of the anodic oxide film cannot be sufficiently changed. In addition, if the treatment time exceeds 10 minutes, the abrasion resistance of the anodic oxide film decreases, so the treatment time exceeds 10 minutes.
Preferably within minutes. When alternating current is used in this electrolytic treatment, the change in characteristics that occurs in the previously applied anodic oxide film can be made larger than when direct current is used. On the other hand, although direct current can be said to have a narrower range of changes in the anodic oxide film than alternating current, it has the effect of suppressing the current density during electrolytic treatment, and the performance of the colored film is better than that of alternating current. It will be good. Such an electrolytic treatment step is closely linked to the next hot water washing step, and both treatment steps are essential steps in the method of the present invention.

In other words, as described below, the condition for patterning is that a substance that inhibits or accelerates electrolytic coloring is attached to aluminum, but in order for this inhibiting or accelerating substance to attach, the surface of the aluminum must be dry. state is required. Generally, aluminum is washed with water after being energized, but since the surface is difficult to dry after washing with water, hot water washing is practically optimal in order to increase production efficiency. However, when an anodic oxide film obtained by a conventional method is simply washed with hot water, the anodic oxide film becomes pore-sealed and loses its activity, and metals involved in coloring are precipitated during electrolytic coloring in the subsequent process. I ended up not being able to color it at all.

Therefore, in the present invention, in order to enable a wound cleaning treatment without such a sealing action, an electrolytic treatment is required to change the characteristics as described above. On the other hand, if electrolytic treatment is performed to change the properties mentioned above, but electrolytic coloring is performed without performing scratch cleaning treatment, the anodic oxide film will of course be colored, but the coverage during coloring will not be good. It has the disadvantage that a uniform and beautiful colored anodic oxide film cannot be obtained, and hot water washing is required to obtain a practical film.

By carrying out this scratch cleaning treatment, the activity of the anodic oxide film whose characteristics have been changed is made uniform over the entire aluminum surface, thereby ensuring that there is no variation in metal deposition during the subsequent electrolytic coloring treatment. be.

As a general rule, it is preferable to use pure water as the condition for cleaning wounds, but it is not necessary to be limited to this, and a water containing a surfactant near neutrality may also be used.

The anodic oxide film is in a state where it is difficult to be sealed by the above electrolytic treatment, but in order to enable hot water washing without pore sealing, the treatment time is 1 to 3 minutes when the temperature is 50 to 9,000. , 90 to 10 pi, the preferred time is 1 to 15 minutes, and can be freely selected within this range.

Therefore, when the anodic oxide film whose characteristics have been changed as described above is subjected to scratch cleaning treatment, the surface condition of the anodic oxide film becomes uniform without being sealed. The material quickly becomes dry and can be moved to the next process of depositing an electrolytic coloring inhibiting substance or an electrolytic coloring promoting substance for patterning.

Substances that inhibit electrolytic coloring are those that do not conduct electricity during the process, or those that inhibit the coloring action itself due to the nature of the substance, making it difficult for metals etc. to be deposited in the micropores of the anodic oxide film. .

The former substances include insulating substances such as kaolin, dibutyl phthalate, acetate, glycerin, ethylene glycol, higher fatty acid esters, resist tinctures, and various synthetic resins, and the latter substances include sodium ions, potassium ions, and ammonium by hydrolysis. Substances that generate ions and nitrate ions are used, such as aqueous solutions of sodium hydroxide, potassium hydroxide, aqueous ammonia, nitric acid, sodium nitrate, sodium sulfate, ammonium sulfate, potassium sulfate, and pastes thereof. As a substance that accelerates the electrolytic coloring treatment, an aqueous solution of concentrated sulfuric acid, phosphoric acid, phosphorous acid, sulfuric acid amide, carboxylic acid, or oxycarboxylic acid, or a paste thereof is used.

Further, by using a mannequin tape, the electrolytic coloring treatment can be inhibited.

The above-mentioned electrolytic coloring inhibiting substances and electrolytic coloring promoting substances can be attached to the surface of aluminum by not only applying or pasting them directly on the surface, but also using various printing methods such as screen printing and offset printing. can do.

The following method is especially advantageous for aluminum having a complicated uneven surface. This involves floating a thin film on which the electrolytic coloring inhibiting substance or electrolytic coloring accelerating substance is printed in an appropriate design pattern on a liquid with the printed side facing up.
By pressing the aluminum against the printing surface and submerging it in the liquid, the liquid pressure is used to tightly adhere the thin film to the entire surface of the aluminum, thereby attaching inhibitors or promoters of the printing surface to the aluminum surface. This is a method of fixing it.

In this method, it is necessary to remove the thin film after the inhibitor or promoter has been deposited on the aluminum surface, and various means such as scratch cleaning are used for this purpose.

After the above-mentioned inhibiting substance or promoting substance is deposited in a pattern on the aluminum surface in this way, an electrolytic coloring treatment is performed.There are no particular limitations on the electrolytic coloring treatment conditions, and conventionally known methods can be adopted as appropriate. be able to.

For example, acids or salts of various metals involved in coloring, such as nickel, cobalt, copper, tin, manganese, zinc, chromium, iron, lead, and molybdenum. Examples include a method of performing electrolytic treatment in a colored bath containing hydrogen water using an appropriate current waveform such as AC electrolysis, DC cathode electrolysis, or AC/DC superimposed electrolysis.

When this type of electrolytic coloring treatment is performed, even though hot water washing is performed, electrolytic treatment is performed to change the characteristics of the anodic oxide film as a pre-process, so the anodic oxide film becomes bronze, amber, or black. Naturally, they are colored in various tones such as green, blue, red, yellow, and brown.

By the way, the part where the electrolytic coloring inhibitor is fixed is not colored, so it remains the base color of aluminum, and in the end,
A pattern is generated using the ground color and the coloring. In addition,
If the anodizing treatment involves color development, a colored pattern is drawn based on the difference between the color tone caused by the color development and the color tone caused by electrolytic coloring.

On the other hand, when an electrolytic coloring promoting substance is fixed, the degree of coloring of the fixed part is promoted more than other parts, and the color tone becomes purulent or a different hue, and the coloring is based on the difference between the concerned color tone and the other color tone. A pattern is drawn.

In addition, in the method of the present invention, although electrolytic treatment is performed to change the characteristics of the anodic oxide film, the activity of the film is made uniform by the hot water washing treatment in the next step, so that the electrolytic coloring process can be improved. The coloring has good coverage and is uniformly colored over the entire uneven surface.

Incidentally, after the electrolytic coloring treatment, the electrolytic coloring inhibiting substances or promoting substances that are adhered and fixed on the surface of the aluminum may be removed or not depending on their properties.

For removal, hot water washing or immersion in an organic solvent is performed. Examples of the method of the invention are as follows.

Example 1 Aluminum alloy A606$ was immersed in 1 skin t% nitric acid for 5 minutes, degreased and washed, and then immersed in 5 wt% sodium hydroxide at 50q○ for 8 minutes to perform etching treatment.
Smut is removed by soaking in 1 t% nitric acid.

Next, this aluminum alloy was heated in 15M% sulfuric acid at a bath temperature of 2
After anodizing for 3 minutes at 0°C and electrolysis of 1.0 A/ground, anodizing was carried out in a phosphorous acid bath of 100 m/d at ambient temperature of 20 m/d. C. Electrolyze for 4 minutes at 10V. Furthermore, this aluminum alloy was immersed in 80 oo of pure water for 1 minute and washed with hot water. After drying the surface of the aluminum alloy, a thin film printed in a desired pattern with grease was brought into close contact with water pressure, and the grease was applied. was attached to the surface of the aluminum alloy according to the pattern. This aluminum alloy was immersed in 60 ml of pure water for 15 minutes to remove the water-soluble thin film, and then immersed in stannous sulfuric acid for 10 min., sulfuric acid for 10 min. C. When electrolysis was carried out between four current sands under the condition of 25V, the parts other than those to which the grease was attached were colored green. When the aluminum alloy was soaked in boiling water for about 5 minutes to remove the grease, a patterned colored film consisting of the silvery gray and green of the fabric was formed on the aluminum alloy surface. Example 2 After subjecting an aluminum plate AI20 Misaki to the same pretreatment and anodizing treatment as in Example 1, it was connected to an anode with a sulfuric acid rating of 55V/V%, and was heated at a normal temperature of 20°C and 20V. Electrolytic treatment was performed for 7 minutes.

Next, this aluminum plate was immersed in pure water at 85°C for 5 minutes, washed with hot water, and the surface of the aluminum plate was dried and partially covered with masking tape. When the acid is connected to the cathode in the chamber for 40 minutes and electrolyzed between three mice and sand at a bath temperature of 20℃ and 15V, the area other than the area where the masking tape was attached becomes lemon gold, and when the masking tape is removed, the area is colored lemon gold. A beautiful colored film with a pattern consisting of the silvery gray and monogold colors of the fabric was formed on the aluminum slope. Example 3 Aluminum alloy A606$ was pretreated and anodized in the same manner as in Example 1, and then sulfuric acid amide 1502/〆, pyrophosphoric acid 5
0 evening/The normal temperature in the bath was 25℃, D. C. Electrolyze for 5 minutes at 15V. Next, a mixture of dibutyl acetate and petrolatum was applied in a desired pattern to the surface of the aluminum alloy, which had been immersed in 70 qo of pure water for 3 minutes, washed and dried, and then the aluminum alloy was soaked in manganese sulfate. When connected to the cathode in a bath of 10% hydrogen peroxide and electrolyzed for 90 minutes at a temperature of 20°C and 40V, the area other than the areas where dibutyl acetate and vaseline were attached turned brick red. It was done. Next, pure water 100
When the adhered substances were removed by immersion in qo for 5 minutes, a patterned colored film of silver gray and brick red of the fabric was formed on the surface of the aluminum alloy. Example 4 After subjecting an aluminum plate AIO cape to the same pretreatment and anodizing treatment as in Example 1, it was connected to an anode in the immersion of phosphoric acid 150 pm/night and tartaric acid 30 pm/day, and the bath temperature was 20°C. ,
D. C. Electrolyze for 2 minutes at 15V.

Next, a resist ink was applied to the surface of the aluminum plate, which had been immersed in pure water at 80°C for 4 minutes, washed with hot water, and dried, by screen printing to form a desired pattern. 5th evening / Temperature 2 pi○, electrolytic 2.0A in the Yuro
When anodic oxidized for 20 minutes under the conditions of /c ra, it was colored greenish amber. When the resist ink on this aluminum plate was removed with an organic solvent, a patterned colored film consisting of the silvery gray and greenish amber color of the fabric was formed. Example 5 Aluminum alloy A606 was subjected to the same pretreatment and anodic oxidation treatment as in Example 1, and then treated with ammonium phosphate for 50 t/day and chromic acid for 50 t/d at a temperature of 15 oo.
, A.C. Electrolysis was carried out for 6 minutes at 25V.

Next, after drying the surface of the aluminum alloy which has been immersed in 90 qo of pure water for 3 minutes and subjected to moat cleaning treatment, a clear paint is applied according to a desired pattern. Then sulfuric acid steel 30
9/〆, sulfuric acid 5 nights/In the bath, the temperature is 25℃, AC. 20
When electromagnetic was applied for 2 minutes under the condition of V, the parts other than those to which the clear paint was attached were colored coppery red. When the entire structure was coated with clear paint, a beautiful patterned colored film consisting of the silvery gray and coppery colors of the fabric was formed on the aluminum alloy surface. Example 6 Aluminum alloy A606$ was subjected to the same pretreatment and anodizing treatment as in Example 1, and then heated to a temperature of 2 p.m. in phosphorous acid at a temperature of 2 p.m. C. 3 under 30V condition
Electrolyzed for minutes.

Claims (1)

[Claims] 1 Aluminum with an anodic oxide film formed by a conventional method is subjected to structural changes in the micropores of the anodic oxide film.
Organic acids containing OH or -COOH groups, orthophosphoric acid, pyrophosphoric acid, chromic acid, phosphorous acid, sulfuric acid, 4
AC in a bath mainly containing high concentration sulfuric acid with a concentration of 0V/V% or more or one or more of these salts, or a current with a waveform that alternates between positive and negative polarity, a DC anode, or an AC/DC current. Electrolytic treatment is performed using a superimposed current at a voltage of 5 to 50 V for 1 minute or more, followed by hot water washing treatment, and the dried surface of the aluminum is treated with substances that inhibit the electrolytic coloring treatment in the subsequent process or which promotes the electrolytic coloring treatment. By depositing the substance in an appropriate pattern and then electrolytically coloring the aluminum with the inhibitor or promoter still attached, the difference between the area to which the inhibitor or promoter is attached and the area to which it is not attached is determined. A patterned surface treatment method for aluminum, characterized by generating a pattern based on.