JPS6025518B2 - 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.

BACKGROUND ART Conventionally, various methods have been proposed for generating patterns on the surface of aluminum for building materials having a complicated cross-sectional shape, including immersing 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 pattern created by this method depends exclusively on the upward trajectory of hydrogen gas, only a monotonous line pattern or straight grain pattern can be obtained, and it is not possible to obtain a pattern suitable for the exterior design depending on the use of aluminum. There are inconveniences that cannot be avoided.

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 monotonous line patterns but also free design patterns similar to printing methods, 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 an 10H group or a -COO group, orthophosphoric acid, or pyrophosphoric acid, which causes a structural change in the micropores of the anodic oxide film. , phosphorous acid, chromic acid,
Alternating current or similar waveform current or direct current with alternating positive and negative polarities in a bath 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
After electrolytic treatment with V for 1 minute or more, a primary coloring treatment is performed to produce a colored anodic oxide film, followed by a hot water washing treatment, and a post-process secondary electrolytic coloring treatment is applied to the dried aluminum surface. By depositing the inhibiting substance in an appropriate pattern and then applying a secondary electrolytic coloring treatment to the aluminum with the inhibiting substance attached, the difference in color tone between the area to which the inhibitor is attached and the area to which it is not attached can be determined. It is characterized by generating a pattern based on.

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 remove aluminum that has been pretreated by degreasing, cleaning, etching, removing smut, etc. 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, a process involving color development may be performed. Then, the aluminum anodic oxide film produced in this way is further electrolytically treated to change the properties of the anodic oxide film, but the change in properties means that the structure of the micropores is different from that of the conventional method. For example, make it complicated.

The treatment bath for this purpose mainly contains one or more inorganic acids among orthophosphoric acid, pyrophosphoric acid, phosphorous acid, chromic acid, sulfuric acid, high concentration sulfuric acid of 40 V/V% or more, or their salts. In addition, -O such as malic acid, gluconic acid, maleic acid, citric acid, malonic acid, tartaric acid, cresolsulfonic acid, sulfophthalic acid, sulfosalicylic acid, gallic acid, benzoic acid, phthalic acid, and carbolic acid
A case mainly containing 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 gutter characteristics are alternately converted, a direct current anode, or an AC/DC superimposed current is used.

The processing current is 5 to 50y, 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. Also, if the treatment time exceeds 10 minutes, the abrasion resistance of the anodic oxide film will decrease, so
Preferably within 0 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. After this electrolytic treatment, a primary coloring treatment is performed.

The primary coloring process here is not particularly special, and any conventionally known method can be employed as appropriate. For example, nickel, cobalt, copper, tin, manganese, zinc, chromium, iron,
Coloring compounds containing acids or salts of various metals involved in coloring lead, molybdenum, etc., AC electrolysis, DC cathodic electrolysis or AC Examples include a method of electrolytic treatment using an appropriate current waveform, such as superimposed electrolysis.

Alternatively, it may be colored by dyeing treatment. Through this primary coloring process, the anodized film can be colored not only in traditional colors such as bronze, amber, and black, but also in green, blue, red, yellow, and other colors.
Colored in various tones, including brown.

After this, the colored anodic oxide film is washed with hot water.
This hot water washing treatment is closely linked to the electrolytic treatment for changing the properties, and both steps are essential in the method of the present invention.

That is, in the present invention, a condition for patterning is to attach a substance to aluminum that inhibits the secondary electrolytic coloring treatment in the subsequent process, but in order for this inhibitor to adhere, the aluminum surface must be dry. A state of being is required. Generally, aluminum is washed with water after being energized, but since the surface of aluminum is difficult to dry after washing with water, a scratch washing process is practically optimal in order to increase production efficiency.

However, when an anodic oxide film or a colored anodized film obtained by a conventional method is simply washed with hot water, it becomes sealed and loses its activity as an anodized film, and the coloring does not occur in the subsequent electrolytic coloring process. This means that the metals involved in this cannot be precipitated. Therefore, in the present invention, in order to enable a wound cleaning treatment without such a sealing effect, an electrolytic treatment is required to change the characteristics as described above, and the electrolytic treatment changes the anodic oxide film. Characteristics change to make it difficult to seal.

As a general rule, it is preferable to use pure water as the condition for hot water washing, but it is not necessary to be limited to this, and it is also possible to use water containing a surfactant near neutrality or water containing other chemicals as appropriate.

The processing time that enables hot water washing without sealing is 50 minutes.
-9pi 0 for 1 to 30 minutes, 90 to 10 and ○ for 1 to 10 minutes, and can be freely selected within this range. Note that a primary coloring treatment step is interposed between the electrolytic treatment step for changing the characteristics and the scratch cleaning treatment step, but this treatment step simply adds metal into the micropores of the anodic oxide film whose characteristics have been changed. It only causes precipitation and dyeing, and does not further change the properties of the anodic oxide film, and has no adverse effect on the hot water washing treatment effect in the subsequent process.

When the colored anodic oxide film whose properties have been changed as described above is washed with hot water, the surface condition of the colored anodic oxide film becomes uniform without being sealed. It quickly becomes dry and can be moved to the next step of electrolytic coloring inhibitor deposition treatment 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. . Examples of the former include insulating substances such as kaolin, dibutyl phthalate, acetate, glycerin, ethylene glycol, higher fatty acid esters, resist inks, and various synthetic resins; examples of the latter include sodium ions and potassium ion by hydrolysis. Substances that generate ions, ammonium ions, and nitrate ions are used, and specifically, aqueous solutions such as sodium hydroxide, potassium hydroxide, aqueous ammonia, nitric acid, sodium nitrate, sodium sulfate, ammonium sulfate, and potassium sulfate, and pastes of these are used. I can give you something.

Furthermore, the electrolytic coloring process can be inhibited by using a masking tape.

As a means for attaching the electrolytic coloring inhibitor as described above to the surface of aluminum, various printing methods such as screen printing and offset printing can be used as well as direct coating or pasting on the surface.

In particular, the following method is advantageous for aluminum that has a complex uneven surface.

It uses liquid pressure by floating a thin film printed with the electrolytic coloring inhibitor in a suitable design pattern on the liquid surface with the printed side facing up, and then submerging the aluminum into the liquid while pressing the printed side. This allows the thin film to adhere to the entire surface of the aluminum, thereby causing any inhibitors on the printing surface to adhere to the surface of the aluminum.

In this method, it is necessary to attach the inhibitor to the aluminum surface and then remove the thin film using various means such as hot water washing. After the above-mentioned inhibitory substance is deposited in a pattern on the surface of aluminum in this way, a secondary electrolytic coloring treatment is performed, and this secondary electrolytic coloring treatment method is similar to the above-mentioned primary electrolytic coloring treatment method. It is sufficient to use a conventionally known method without using any special method, but it is possible to adopt as appropriate whether the primary and secondary processing conditions are the same or different.

In the secondary electrolytic coloring treatment, even though hot water washing is performed first, the activity is maintained due to the electrolytic treatment to change the characteristics of the anodic oxide film as a pre-process, so the primary coloring is The anodic oxide film that has been colored by the treatment is further colored.

By the way, as mentioned above, the electrolytic coloring inhibiting substance is attached to the surface of aluminum, but when an insulating substance is attached, the effect of the secondary electrolytic coloring treatment does not reach the attached part. The color tone obtained by the primary coloring process remains the same.

Therefore, a pattern is formed on the surface of the aluminum that covers the difference between the color tone obtained by the primary coloring treatment and the color tone obtained by the secondary electrolytic coloring treatment. In addition, if a substance that inhibits the coloring effect is attached, the secondary electrolytic coloring treatment does not progress much in the attached area, and the degree of coloring is different from the non-adhered area, resulting in a difference between the attached area and the non-adhered area. A colored pattern is generated based on the degree of coloring.

Incidentally, after the secondary electrolytic coloring treatment, the electrolytic coloring inhibiting substance adhering to the surface of the aluminum may be removed or not depending on its properties.

In the case of removal, hot water washing treatment or immersion treatment in an organic solvent is performed. As described above, the present invention generates a pattern by adhering an electrolytic coloring inhibitor, and there is no restriction on the means for this adhesion, and various methods including printing can be used. Not only can you choose the design freely, but you can also reliably and easily reproduce the same pattern.

Examples of the method of the present invention will be described below.

Example 1 Aluminum alloy A606$ was soaked in lOWt% nitric acid for degreasing and cleaning, then immersed in a 5wt% sodium hydroxide solution at 5000 for 10 minutes for etching treatment, and then soaked in lOWt% nitric acid. smut was removed.

This aluminum alloy was mixed with 15 wt% sulfuric acid and 20 qo
After anodizing for 30 minutes at an exposure density of 1.0 A/d, the anode was connected to the anode in a bath of phosphorous acid at a temperature of 100 m/d. C. Electrolytic treatment was performed at 20V for 3 minutes. Subsequently, this aluminum alloy was heated to nickel sulfate for 30 pm/day and shelf acid for 30 pm/day at a temperature of 20 oo.
, A.C. When electrolyzed for a minute at 10 V, the anodic oxide film was colored gray-blue. Next, this aluminum alloy was soaked in 80 qo pure water for 10 minutes and washed with hot water, and then glycerin was adhered to the surface of the dried aluminum alloy in an appropriate pattern. This aluminum alloy is nickel sulfate 30
Evening: So, 30 evenings: Temperature: 20℃, A. C
．． When electrolyzed for 5 minutes at 15 V, the areas other than those to which glycerin was attached were colored dark bronze. After that, pure water 900
When washed with hot water for 0.15 minutes, the glycerin was removed and a patterned colored film consisting of gray-blue and deep bronze colors was formed. Example 2 Aluminum alloy A606$ was subjected to the same pretreatment and anodic oxidation film as in Example 1, and then treated with orthophosphoric acid 20
0 evening/evening, 5 evenings/in the Yuan, temperature 25℃, A. C.
Electrolysis was carried out for 5 minutes at 15V.

Then, in a bath of manganese sulfate for 20 minutes and 20 hours of hydrogen peroxide solution, it was connected to the cathode and heated at a temperature of 20°C. C. 3
When electrolyzed for 1 minute under 0V conditions, it was colored ocher. Then, after soaking in 80 qo pure water for 1 minute and washing with hot water,
A thin film of an aqueous solution printed in a desired pattern with dimethyl phthalate was brought into close contact with the surface of the dried aluminum alloy using water pressure, so that the dimethyl phthalate adhered in the pattern. Continue to pour this aluminum alloy into pure water.
After removing the water-soluble thin film soaked for 20 minutes at 0qo, the dried aluminum alloy was soaked in 20% manganese sulfate.
In the evening, 20 vessels of hydrogen peroxide solution were connected to the cathode in the tank, and the temperature was 20°C. C. When electrolyzed for 2 minutes under the condition of 50V, the parts other than those to which dimethyl phthalate was attached were colored dark brown. This aluminum alloy has a grade of 8000 pure water.
After soaking for 0 minutes to remove dimethyl phthalate, a transparent clear coating was applied, and a beautiful ocher and dark brown patterned colored film was formed on the aluminum alloy surface. Example 3 After subjecting an aluminum plate AI200P to the same pretreatment and anodic oxidation treatment as in Example 1, it was heated in a 50V/V% sulfuric acid bath at a bath temperature of 15qC and D.C. C. (10) Electrolytic treatment was carried out for 7 minutes under the condition of 10V, and then connected to the cathode in a chamber of nickel sulfate at 40 m/s and shelf acid at 40 m/m. C.
When electrolyzed for 1 minute at 20V, the anodic oxide film was colored golden yellow.

After immersion in 10,000 pure water for 5 minutes and washing with hot water, the surface of the dried aluminum plate was screen printed in a desired pattern using a clear paint. Next, this aluminum plate was exposed to stannous sulfate for 10 days and sulfuric acid for 10 days in a bath at a temperature of 20 degrees Celsius. C. 5 under 20V condition
When electrolyzed for a minute, the parts other than those to which the clear paint was attached were colored black.

After that, the aluminum plate was immersed in 80 oo of pure water for 10 minutes, and then the entire plate was coated with a clear coat, producing a colored film with a beautiful pattern of golden yellow and black on the aluminum plate. Example
4 After subjecting aluminum alloy A606$ to the same pretreatment and anodizing treatment as in Example 1, it was connected to the anode in a bath of chromic acid 100 pm/night and sulfuric acid 5 pm/day, and the bath temperature was 26 pm.
0,D. C. Electrolytic treatment was carried out under the conditions of 35 V, and then connected to the cathode in a bath of cobalt sulfate 40 pm/night and shelf acid 30 pm/day, bath temperature 20 qo, D.C. C. When electrolyzed for 3 minutes at 18V, the anodic oxide film was colored yellowish bronze.

After washing the wound by immersing it in 70 oo of pure water for 8 minutes,
A resist ink was partially applied to the surface of a dry aluminum alloy. Next, this aluminum alloy was connected to the cathode in a bath of cobalt sulfate 30 minutes/day and hydrogen peroxide solution 20 minutes/day, and heated at a temperature of 20 degrees Celsius. C. When electrolyzed for 5 minutes under the condition of 40V, the parts other than those to which the resist ink was attached were colored brick-red. Thereafter, when the resist ink was removed with an organic solvent, a colored film with a pattern consisting of yellowish bronze and red was formed on the aluminum alloy. Example 5 After performing the same pretreatment and anodic oxidation treatment as in Example 1, an aluminum plate AIlOOP was treated with sulfuric acid amide at 80 t/h and pyrophosphoric acid at 50 t/m in a room temperature of 20 qo.
A.C. It was electrolyzed for 3 minutes under the condition of 20V, and then immersed in an aqueous solution of ferric ammonium noctilate at 5000V for 1 minute to dye it golden yellow.

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, phosphorous acid, chromic acid, sulfuric acid amide, 4
AC or similar waveform current with alternating positive and negative polarity, DC anode or AC/DC in a bath mainly containing high concentration sulfuric acid of 0v/v% or more or one or more of these salts. After electrolytic treatment using a superimposed current at a voltage of 5 to 50 V for more than 1 minute, a primary coloring treatment is performed to produce a colored anodic oxide film, followed by a hot water washing treatment and a post-treatment on the dry aluminum surface. By attaching a substance that inhibits the secondary electrolytic coloring treatment in the process in an appropriate pattern, and then applying the secondary electrolytic coloring treatment to the aluminum with this inhibitory substance attached, the above-mentioned inhibitory substance-adhered portion is removed. A patterned surface treatment method for aluminum, characterized in that a pattern is generated based on the difference in color tone of a non-adhesive part.