JPS621550B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a surface treatment method for producing a pattern on the surface of aluminum.

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

Conventionally, various methods have been proposed to create patterns on the surface of aluminum, which has a complex cross-sectional shape and is used for various purposes such as building materials and furniture, by immersing the aluminum before anodizing in a certain liquid and treating it with electricity. has been done.

In such a method, hydrogen gas generated on the surface of aluminum by current treatment forms an upward locus on the surface of the aluminum, and this locus forms a pattern. However, the generation of hydrogen gas during the energization process is not constant and is extremely irregular, making it impossible to reproduce a consistent and regular pattern on the surface of aluminum, and it is difficult to reproduce the same pattern on different aluminum surfaces. There are inconveniences that cannot be avoided.

In addition, since the patterns produced by this method depend exclusively on the upward trajectory of hydrogen gas, only monotonous line patterns or straight-grained patterns can be obtained, making it difficult to create patterns suitable for the exterior design of aluminum for various uses. It has disadvantages that cannot be obtained.

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

Therefore, the present invention provides a patterned surface treatment method that can generate not only a monotonous line pattern but also a free design pattern in the same way as a printing method, even on aluminum for building materials having a complicated cross-sectional shape. For this purpose, we have devised our own ingenuity to create a product that uses an ultraviolet curable resin and cures it by irradiating it with ultraviolet rays. This system generates a colored pattern based on the difference between the two colors.

The method of the present invention will be described in detail below.

First, an anodic oxide film is formed on the surface of the aluminum, which is pretreated by conventional methods such as degreasing, cleaning, etching, and removal of smut. In a bath that produces a porous oxide film, electrolytic treatment is performed using direct current electrolysis, alternating current electrolysis, alternating current electrolysis, alternating current electrolysis, or other current waveforms having equivalent effects. Normal anodic oxide film does not produce color, but
Color may be developed during the formation of this anodic oxide film.

In addition, a non-colored anodic oxide film that does not develop color can be made into a colored film by performing the following treatment.

(1) Use appropriate current waveforms such as AC electrolysis, DC cathode electrolysis, or AC/DC superimposed electrolysis in a coloring bath mainly composed of acids or salts of various metals involved in coloring nickel, cobalt, copper, tin, manganese, etc. A method of applying electrolytic coloring treatment.

(2) Baths and apples containing one or more inorganic acids among orthophosphoric acid, pyrophosphoric acid, phosphorous acid, chromic acid, sulfuric acid amide, high concentration sulfuric acid of 40V/V% or more, or salts thereof. acid, maleic acid,
A bath mainly consisting of one or more of various organic acids containing -OH or -COOH groups, such as citric acid, tartaric acid, sulfosalicylic acid, and gallic acid, or their salts, or a mixture of these baths as appropriate. By immersing an aluminum anodic oxide film in a bath and energizing it using direct current, alternating current, a waveform that alternates positive and negative polarity, or an AC/DC superimposed waveform, the fine pores of the anodized film are removed. After changing the structure, electrolytic coloring is performed in a coloring bath in the same way as in (1).

(3) A method of coloring by dipping in dye.

As mentioned above, an ultraviolet curable resin paint is applied to a colored (including coloring) anodic oxide film or to an uncolored anodic oxide film. The main ingredient is a photopolymerizable prepolymer such as mold, urethane type, epoxy type, polyether type, etc., as well as a photopolymerization initiator that absorbs ultraviolet rays and starts the polymerization reaction, a photopolymerizable monomer as a diluent, and pigments. It consists of various additives.

After the ultraviolet curable resin paint is applied uniformly to the entire surface of the aluminum, it is irradiated with ultraviolet rays. A shielding body 4 having a pattern-like transparent part 3 formed thereon is interposed between the aluminum 2 so that only the ultraviolet rays that have passed through the transparent part 3 can be irradiated, and a resin paint 6 is applied according to the shape of the transparent part 3. A method of partially curing the coating film 6a to form a patterned coating film 6a that is in close contact with the anodic oxide film is mentioned.

In this method, the shielding body 4 consists of an ultraviolet transmitting part 3 and an ultraviolet absorbing part 5, and the ultraviolet transmitting part 3 has a content of iron oxide contained as an impurity.
It is made of low alkali borosilicate glass or phosphate lime glass with a content of 0.01%, and the ultraviolet absorbing part 5 is made of glass with an iron oxide content of about 1%, and the absorption property is increased by adding cerium ions. can be increased. Other effective substances that enhance this ultraviolet absorption include quartz, potassium chloride, silica, and lithium fluoride.

In addition, the portions that remain uncured due to the ultraviolet rays being blocked by the shielding member 4 are removed by spraying an appropriate removal liquid such as water, and are adhered to the anodic oxide film in a pattern. Only the cured resin coating layer remains (Figure 2). That is, a pattern with a different color tone is formed between the part where the paint film layer is formed and the part where the paint film layer is not shaped.

Note that 7 in the figure represents a colored film.

In each of the above methods, if the anodic oxide film is in a non-colored state, various pigments may be added to the ultraviolet curable resin paint, or if the anodic oxide film is colored or developed, these methods may be applied. By adding a pigment with a different color tone to the resin paint, it is possible to create a vivid colored pattern.

The above contents can be summarized as follows.

(1) After applying pigment-added ultraviolet curable resin paint to the uncolored anodic oxide film,
Ultraviolet rays are partially irradiated through a shielding plate having an ultraviolet transmitting portion to form a cured coating layer in a pattern according to the transmitting portion.

(2) After applying an ultraviolet curable resin paint containing pigments to the entire colored or developed anodic oxide film, irradiate the area with ultraviolet rays through a shielding plate that has an ultraviolet transmitting area, and then to form a pattern-cured coating layer.

By repeating these methods, as shown in Figure 3, a further cured ultraviolet curable resin coating layer is layered on top of the patterned ultraviolet curable resin coating layer, creating a three-dimensional pattern. It is possible to form an uneven pattern.

In addition, in the present invention, after the ultraviolet ray curable resin coating is irradiated with ultraviolet rays, it can be further subjected to an electrolytic coloring treatment. This electrolytic coloring treatment is carried out by applying electricity in the electrolytic coloring bath described above, but since the cured ultraviolet curable resin coating layer does not conduct electricity, it functions as a masking material and the coating layer is The part where the film layer is formed is not electrolytically colored, and the part where the film layer is not electrolytically colored and the part where the film layer is not formed, that is, the electrolytically colored anodic oxide film part, are colored in different shades or different tones. It is possible to generate patterns.

In this case, the anodic oxide film to which the ultraviolet curable resin paint is attached has been treated as described below.

(a) Non-colored or colored state by the above-mentioned anodic oxidation treatment.

(b) The uncolored anodic oxide film is treated with one or more of orthophosphoric acid, pyrophosphoric acid, phosphorous acid, chromic acid, sulfuric acid, high concentration sulfuric acid of 40V/V% or more, or their salts. Baths based on inorganic acids, -OH group or - of malic acid, maleic acid, citric acid, sulfosalicylic acid, gallic acid, etc.
A state in which the micropore structure of an anodic oxide film is changed by immersion in a bath mainly containing one or more of various organic acids containing COOH groups or their salts and then energized.

(c) A state in which an anodized film is electrolytically treated to form a colored film in a coloring bath containing acids or salts of various metals involved in coloring, such as nickel, cobalt, copper, and manganese.

(d) After changing the micropore structure of the anodic oxide film using the method (b) above, electrolytically color the film using the method (c) above to create a color tone different from that obtained using the method (c) above. Colored state.

Transparent ultraviolet curable resin paints with or without pigments are applied to these anodic oxide films in various states, and the method of irradiating ultraviolet rays to partially cure the adhesive is as described above. .

In the subsequent electrolytic coloring treatment, it is important to decide whether or not to add pigments to the UV-curable resin paint in relation to the color tone produced by the electrolytic coloring treatment, and whether or not the anodic oxide film is colored (colored) before the pigment is attached to the UV-curable resin paint. Various color combinations are possible depending on whether the

Taking this point into consideration, the processing steps are summarized as follows.

(b) A transparent ultraviolet curable resin paint is attached to the anodic oxide film (non-color forming), a coating layer is formed partially by ultraviolet irradiation, and then electrolytic coloring is performed.

At this time, the part where the paint layer is not formed is colored while the non-colored anodic oxide film remains as it is.

(b) After adhering an ultraviolet curable resin paint containing pigments to the anodic oxide film (non-coloring) and partially forming a coating layer by irradiating it with ultraviolet rays, electrolytic coloring treatment is performed. At this time, a colored pattern is formed by the paint layer containing the pigment and other electrolytically colored parts.

(c) A transparent (or pigment-containing) ultraviolet curable resin paint is attached to an anodic oxide film (non-colored) with a change in the micropore structure, and a coating layer is formed partially by ultraviolet irradiation. Afterwards, do electrolytic coloring.
In this case, the areas other than the areas where the coating film layer is formed have a color tone different from that obtained by normal coloring treatment.

(d) After the first electrolytic coloring treatment is applied to the anodic oxide film (non-coloring) in a coloring bath mainly composed of salts of various metals or acids, a transparent ultraviolet curable resin paint is applied. A coating layer is formed partially by ultraviolet irradiation, and then a second electrolytic coloring treatment is performed. In this case, the second electrolytic coloring effect does not reach the part where the coating layer is formed, and the color tone from the first electrolytic coloring is maintained, and the other parts are due to the first and second electrolytic coloring. It becomes a complex color tone.

(e) The anodic oxide film (non-colored) with a change in the micropore structure is subjected to the first electrolytic coloring treatment shown in (d) above to give it a different color tone than the normal coloring treatment, and then it becomes transparent. A UV curable resin paint is applied, a coating layer is formed partially by irradiation with UV rays, and then a second electrolytic coloring treatment is performed. In this case, the effect of the secondary electrolytic coloring treatment does not reach the areas where the paint film layer is formed, and the color tone from the primary electrolytic coloring process is maintained, and the areas where the paint film layer is not formed are affected by the primary and secondary electrolytic coloring treatments. The next step is electrolytic coloring, which results in a complex color tone.

As described above, the present invention skillfully utilizes the characteristics of an ultraviolet-curing resin paint when forming a pattern, and the paint is cured in a short time by ultraviolet irradiation, and the anode Since it is in close contact with the oxide film, the time required for pattern formation can be shortened and the efficiency of surface treatment work can be improved.

Examples of the present invention will be shown below.

Example 1 After degreasing and cleaning an aluminum plate A1200P in a 10Wt% nitric acid bath, it was heated to a 5Wt% sodium hydroxide bath at a bath temperature.
Etching treatment was carried out by immersion at 50°C for 8 minutes, and smut removal was further carried out in a 10 Wt% nitric acid bath. This aluminum plate was heated in a 15Wt% nitric acid bath.
Anodizing was performed for 30 minutes at 20°C and electric density of 1.0A/dm ² . This aluminum plate was placed in a bath of 10 g of ferric ammonium oxalate at a bath temperature of 70°C.
A pale golden dyed film was produced by soaking for a minute. After drying this aluminum plate and coating the entire surface with black ink made of ultraviolet curable resin paint (Daikyure UV Ink SSK type, manufactured by Dainippon Ink Co., Ltd.), it is placed between the aluminum plate and a high-pressure mercury lamp. When ultraviolet rays were irradiated for 1 second through a shielding plate having a polka-dot-shaped ultraviolet-transmissive area, the ultraviolet-curable resin paint cured into a polka-dot pattern and adhered to the anodic oxide film.

Next, when the uncured ultraviolet curable resin paint was washed off with a jet shower, a black polka dot pattern coating layer was formed on the pale golden anodic oxide film.

[Brief explanation of the drawing]

FIG. 1 is a diagram of ultraviolet irradiation using a shielding plate, and FIGS. 2 and 3 are cross-sectional views of aluminum having a coating layer.

Claims (1)

[Scope of Claims] 1 A UV-curable resin coating layer adhered to an anodic oxide film of aluminum is partially irradiated with ultraviolet rays to form a UV-curable resin coating layer that is partially cured in close contact with the anodic oxide film. A patterned surface treatment method for aluminum, characterized in that by forming a pattern, a pattern having a different color tone is formed between the part where the ultraviolet curable resin coating layer is formed and the part where the coating layer is not formed. 2. The patterned surface treatment method for aluminum according to claim 1, which uses a non-colored anodic oxide film of aluminum and an ultraviolet curable resin paint containing a pigment. 3. The patterned surface treatment method for aluminum according to claim 1, which uses a colored anodic oxide film of aluminum and an ultraviolet curable resin paint to which a pigment of a different color tone is added.