JPH0128119B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method of coloring an oxide film of aluminum or an aluminum alloy using an organic compound.

(Prior Art) Aluminum or aluminum alloys are often used for scales, rulers, front plates, etc. In this case, the homogeneity and porosity of the artificially obtained oxide film are usually utilized. That is, the pores can encapsulate the dye, and the homogeneity ensures a beautiful and uniform appearance of the colored oxide coating. The pore openings can be closed (sealed) by simple post-treatment.
In this case, the oxide film is treated, for example, with boiling water.
During this treatment, aluminum oxide usually incorporates water molecules into its crystal lattice, increasing its volume.
As a result, the pores are closed. This process is generally irreversible, so if the dye is encapsulated in the pores, it is well protected.

To color an oxide film, it is generally contacted with a solution of the appropriate dye to deposit the dye. Other methods use, for example, colored metal oxides obtained in the coating during or after the oxidation of aluminum. It is also known, for example, to deposit a dye onto a coating.

There are a variety of methods reported for obtaining designs in coatings, such as those commonly employed in retsutel. Generally, they can be divided into two groups. namely, the direct method and the indirect method.

In direct methods, dyes, often coagulated by colloids, are applied directly onto the oxide coating, for example by offset printing or screen printing.

Indirect methods generally place a pattern on the oxide film that covers areas that are not to be treated. At that time, in principle, processing can be carried out by a positive method or a negative method. That is, by covering the areas that are not to be colored and then applying the dye, or by first staining the entire coating and covering the areas where the coloring should remain;
The remaining areas are decolorized, for example by etching or by destroying the dye. Patterns can likewise be applied, for example by offset printing or screen printing.

By repeating the operating process, polychromatic effects can also normally be obtained using both methods (direct and indirect). A combination of both methods is generally also possible.

Generally, the application of dyes or patterns is done using mechanical printing means. However, since the latter often require screens, offset printing plates, dies, etc., which are expensive to manufacture, photographic printing methods are usually preferred for small series.

Indirect methods use, for example, photographic varnishes whose solubility changes under the action of light in certain solvents.
For example, if an anodized aluminum plate coated with this is exposed under a negative or positive light and then washed with a suitable solvent, the washed out areas will be blank and can be colored. For example, the direct method utilizes the properties of silver salts, which are exposed to light and then reduced with specific chemicals to form silver images. For example, methods using other photosensitive metal salts are also known.

It is also known, for example, that various azo dyes are suitable for coloring artificial oxide coatings on aluminum. Azo dyes are generally produced when a diazo compound is reacted with a suitable organic compound (a so-called coupler).

(Problems to be Solved by the Invention) In contrast, the concept of the present invention for obtaining this dye is novel. That is, the present invention supplies a diazo compound as a dye raw material onto an oxide film of aluminum or aluminum alloy, places an appropriate pattern there, irradiates electromagnetic waves, and dyes only the non-exposed areas directly on the film. The present invention provides a method for obtaining a colored oxide film in a pattern without using a metal plate printing machine.

In conventional methods for forming a patterned colored layer on an aluminum substrate, special operations such as printing and etching have been required, whether it is a direct method or an indirect method, as described above. In particular, printing on aluminum metal plates required large-scale equipment, and it was difficult for companies that did not have metal plate printing machines or etching equipment to create colored layers with complex patterns on aluminum substrates. .

In order to solve this problem, the present invention provides a method for providing a patterned colored layer on an aluminum substrate without using expensive equipment.

(Means for Solving the Problems) The present inventor has proposed a method of coloring an oxide film of aluminum or an aluminum alloy using an organic compound, the method comprising:
characterized in that a species of diazo compound is introduced and reacted with the formation of a dye by external action or with at least one other organic compound introduced into the pores before or after said diazo compound. I found a way. In the method of the present invention, it is preferable to obtain the oxide film artificially. The oxide coating thus treated can then be further cleaned and/or sealed.

It is also possible to change the dye-forming ability of at least one of the diazo compounds in the oxide coating by treatment with electromagnetic radiation whose wavelength corresponds to or is shorter than the infrared region before forming the dye. can. Irradiation is carried out using electromagnetic radiation, especially in the UV range.

Irradiation is usually carried out after the introduction of at least one diazo compound, but before the start of the reaction.

Excellent artificial oxide coatings of aluminum or aluminum alloys can be obtained by known methods. An excellent method is the direct current sulfuric acid method, the so-called GS method. However, other methods such as sulfuric acid AC method, chromic acid method, Ematal method,
This oxide thin layer can also be obtained by a currentless method or the like.

In the method of the present invention, commercially available aluminum alloys or commercially available aluminum can be used.

However, it is better to use a material with a quality suitable for anodic oxidation.

Examples of diazo compounds which can be used in the process of the invention and which can react by themselves, i.e. by external effects, such as increased temperature, irradiation, changes in the pH value, the action of gases, etc., and which form dyes in the process, are: It is a diazo compound of 1-amino-8-naphthol-3,6-disulfonic acid, so-called H acid.

However, diazo compounds which are transformed to form dyes while being applied to the oxide coating can also be used in the method of the invention.

The invention also encompasses the possibility that at least one diazo compound introduced into the oxide film reacts with a so-called coupler, forming a dye in the process. Suitable diazo compounds are products A, C, HC-1, Y, etc. from Carre, Wiesbaden.

Examples of suitable couplers are products 1, 5, 13, 38 from Carre (Wiesbaden).

Any diazo compound and any so-called coupler can be used in the method of the invention.

Typically, commercially available diazo salts, such as those used for diazo types, are reacted with suitable commercially available couplers.

For example, there is no limit to the concentration of the diazo compound and coupler in the form of an aqueous solution. The concentration chosen is
It usually depends on the solubility of the diazo compound or coupler, the desired purity of the color of the resulting dye, cost factors, etc.

In the case of photosensitive diazo compounds, it is advantageous to work with weak light that does not change the diazo compound.

Generally, the diazo compound is first introduced into the oxide coating, followed by the coupler. However, the reverse order is usually also possible.

It is therefore possible to introduce one of the above-mentioned components into the oxide film and to act on the other component from the outside as a solution or gas, thereby forming an azo dye in the oxide film.

Since coupling of both components often occurs only within a certain PH range, both components can also be introduced into the coating with care such that the PH value is outside the coupling range.

In this case, the dye is formed as soon as the pH value is brought back within the coupling range by an external action, such as an atmosphere of ammonia, hydrogen chloride, etc. Coupling usually occurs in the alkaline range. Reactions within the pores usually proceed instantaneously, but in some cases may extend over a relatively long period of time.

The operation for applying the components is performed, for example, as follows. That is, coating with a cotton ball, immersion in a solution, spraying with a spray gun, injection with a syringe, rolling with a rotary press, etc.

The process of the invention is normally carried out at atmospheric pressure and ambient temperature, although higher or lower temperatures may optionally be employed.

Additionally, as previously mentioned, the treated oxide coating may be further cleaned. This has the advantage that soluble components, which generally do not form dyes, are washed away, thereby avoiding subsequent reactions such as darkening and decomposition of the dye.

Also, as previously mentioned, the treated oxide coating can be further sealed. The advantage of sealing is that the pores are generally closed, making the surface less susceptible to contamination and preventing the dye from being washed away. The seal may be, for example, waxed, varnished (i.e. with varnish protection),
This can be carried out by impregnation with a water repellent such as silicone, treatment with boiling water, treatment with at least one aqueous solution of an appropriate compound such as nickel acetate or cobalt acetate, and the like. It is advantageous to carry out the sealing by treatment with boiling water.

An advantage of the invention is that the oxide film can be coated with one component and different colors can be obtained by selecting the second component.

Another advantage is that insoluble azo dyes (pigments) can be obtained in the oxide coating, which proves to be a great advantage during subsequent processing. For example, it is water resistant and does not bleed when sealed.

Many diazo salts are generally photosensitive. That is, they lose their ability to form azo dyes together with couplers by the action of light. This principle has been used for some time, for example in diazotypes.

Paper coated with a photosensitive diazo salt is usually irradiated under a positive light and then reacted with a coupler.

Furthermore, as previously mentioned, the dye-forming ability of at least one diazo compound in the oxide coating can be altered by irradiation with electromagnetic waves.

In accordance with the invention, a suitable diazo salt is introduced into the oxide coating, fully or partially irradiated under the positive, and reacted with the coupler, usually producing a colored positive copy. This is because the diazo salt at the irradiated site decomposes and loses its ability to form an azo dye with the coupler.

For irradiation, UV light is especially considered. In particular, for the irradiation, actinic radiation tubes, quartz lamps, arc lamps, xenon lamps or sunlight are used as light sources.

There is generally no limit to the possible combinations between diazo compounds, couplers and irradiation. for example,
The diazo compound is first applied to the oxide coating, which is modified by irradiation in the desired type and manner, and the compound thus obtained can then be reacted with the coupler. However, it is also possible to introduce both components into the oxide film and then irradiate it.
Moreover, as mentioned earlier, many other combination possibilities can still be employed to form dyes in the method of the invention.

(Effects of the Invention) According to the method of the present invention, a patterned colored layer can be formed on an aluminum substrate by photolithography without using an expensive printing machine or etching device.

By irradiating the diazo compound applied to the oxide coating, designs, patterns or images can be obtained, for example. The products created in this way can be used as retstel, front plate, ruler, power distribution image (Schaltbilder), etc.
It can be used as a traffic sign, identification card, etc.

The stability of these products produced by the method of the invention corresponds to a minimum extent to that of ordinary anodized aluminum reticle, but is usually much better.

The invention can be explained in detail by the following examples.

Example 1 A pre-chemically matted aluminum sheet or aluminum alloy sheet suitable for decorative anodizing was anodized by a conventional direct current sulfuric acid method under the following conditions.

Electrolyte sulfuric acid 180g/Electrolyte aluminum 5~15g/Electrolyte temperature 19~22℃ Current density 1.5A/dm ² hours 30 minutes After oxidation, the thin plate was post-treated in 15~20% nitric acid for 5 minutes and washed. and dried.

A solution consisting of 10 g of Fast Blue Salt BB (diazotized 4-3mino-2,5-diethoxy-benzanilide zinc double salt), 100 ml of acetic acid (approximately 90%) and eggplant was applied onto the oxide film with a cotton ball. Next, it was left to dry and then dried with a hot air oven. A positive was placed on a thin plate and exposed for 30 seconds using a quartz lamp from a distance of 60 cm.

The exposed sheet was immersed in a solution consisting of 5 g of phloroglucin, 100 ml of distilled water, ammonia solution (25%) PH10 and eggplant. The image immediately appeared dark brown on the bright substrate. The sheets were then thoroughly cleaned and conventionally sealed using hot water at 96-100°C for 30 minutes.

Example 2 A thin plate was treated as in Example 1, except that after exposure it was immersed in the solution described below.

2,3-naphthoic acid morpholinopropylamide (Carre, Wiesbaden: Kappler 38)
3 g distilled water 100 ml and ammonia solution (25%) at PH 10 Immediately a purple image appeared, which after subsequent water washing and sealing lost its reddish color and became more blue.

Example 3 A sheet anodized according to Example 1 was coated with the following solution.

4-Diazo-dimethylaniline zinc chloride (Carre, Wiesbaden: Diazo A) 5 g Hexylresorcinol 5 g Acetic acid (about 90%) 30 g Methyl alcohol Make about 100 ml After 30 seconds, rub the thin plate with a dry cotton ball until dry. Ivy. Exposure was carried out under positive light as described in Example 1. The exposed thin plate was covered with blotter paper that had been impregnated with the solution described below and thoroughly dried.

Ammonium bicarbonate 10 g Polyvinyl alcohol (M4/88 Hoechst) (as a 10% solution in ethanol) 1 ml Ammonia solution (25%) 20 ml Distilled water 100 ml On a hot plate heated to about 120°C for about 20 seconds. (e.g. with an iron). The image developed a dark brown color, but upon subsequent washing it took on a khaki-brown color, which was retained after sealing.

Example 4 A thin plate, pretreated and anodized as in Example 1, was poured with the following solution.

2,4,2',4'-tetraoxy-diphenyl sulfide (Carre, Wiesbaden: Kappler 2)
4g 4-diaz-2-methyl-phenyl-pyrrolidine
ZnCl ₂ (Carre, Wiesbaden: Diazo Y) 6 g Thiourea 4 g Acetic acid (approximately 90%) 5 ml NaHSO ₃ solution (in saturated methanol) 5 ml Butyl glycol 15 ml Methanol 100 ml After drying, exposed as in Example 1 did. However, the exposure time was 1 minute instead of 30 seconds. The exposed thin plate was then heated at 140°C for 1 minute.
A dark brown image appeared, which did not change with subsequent washing and sealing.

Example 5 An anodized, unsealed sheet metal plate (oxide film thickness of at least 18 μm) was sprayed with the following solution.

4-Diazo-2,5-diethoxy-phenylmorpholine 1/2ZnCl ₂ (Carre, Wiesbaden: Diazo HC) 10 g Distilled water 100 ml After drying, an acetate foil was placed on top. This was done by pouring the following solution onto the thin plate side and then drying it.

β-Naphthylamine 5g Urea 10g Ethylcellulose solution (10% in ethanol) 15ml Butyl glycol 15ml Methanol 100ml Place on a hot plate (e.g. iron) heated to 120°C.
By pressing for 20 seconds, an orange color appeared in the coating, which did not change upon subsequent cleaning and sealing.

Example 6 An anodized, unsealed thin plate (oxide film thickness of at least 15 μm) was smeared (cotton ball) with the following solution for 1 minute.

4-Diazo-diethylaniline ZnCl ₂ (Carre, Wiesbaden: Diazo C) 10 g Urea 5 g Distilled water 100 g Eggplant The mixture was then scraped off with a sharpened rubber doctor and dried. After exposure, the thin plate was covered with acetate foil. This was adjusted on the side facing the thin plate as follows. That is, the following solution: 5 g of 1,8-naphthylenediamine, 15 ml of ethyl cellulose solution (10% in ethanol), 10 ml of butyl glycol, and 100 ml of methanol are poured over the eggplant and thoroughly dried. 130 on this foil
A hot plate (for example, an iron) heated to ℃ was pressed for 20 seconds. The image appeared red in areas that were not exposed. The color remained unchanged upon subsequent washing and sealing.

Example 7 The same procedure as in Example 6 was carried out, except that the foil used in Example 5 (not yet heat treated) was used instead of the foil of Example 6. An orange image was formed, which withstood all heat treatments intact.

Example 8 A solution having the following composition was applied for 1 minute to a thin plate that had been pretreated and anodized in the same manner as in Example 1.

4-Diazo-diethylaniline ZnCl ₂ 10g 2,5-dimethyl-4-dimethylaminoethylphenol. HCl (Carre, Wiesbaden: Katsupla-13)
6g adipic acid 1g distilled water 100ml and eggplant Next, rub with a dry cotton ball until dry.
After exposure under positive light (as in Example 1), the sheets were placed in a closed container where the 25% ammonia solution was evaporated in an open shear chamber. The evaporated ammonia gas shifted the PH value of the diazo coupler mixture into the coupling range (from acidic to alkaline). A positive yellow copy was created in a short time. 5
After minutes, the slats were removed from the container, cleaned, and sealed.

Example 9 An anodized, unsealed sheet metal (oxide film thickness of at least 15 μm) was smeared with the following solution for at least 1 minute.

4-Diazo-dimethylaniline zinc double salt (Carre, Wiesbaden: Diazo A) 2 g 2,7-dioxynaphthalene-3,6-disulfonic acid sodium salt (Carre, Kappler 5) 4 g Distilled water 100 ml and eggplant It was then scraped off with a sharp rubber doctor and allowed to dry. It was exposed and developed in the same manner as in Example 8.

After developing in an ammonia atmosphere, the positive copy was blue, and after sealing it became purple.

Example 10 The sheet was treated as in Example 8, but without sealing at the end, it was recoated and processed as in Example 9. In this case, the retsutel was in three colors. After sealing, the colors were yellow (solution of Example 8), purple (Example 9) and light brown (where both colors overlap).

coloring the oxide coating of aluminum or an aluminum alloy with an organic compound, introducing at least one diazo compound into the pores of the oxide coating and reacting with the formation of a dye by external action;
Alternatively, the diazo compound is reacted with at least one other organic compound introduced into the pores before or after the diazo compound.

By exposing the diazo compound introduced into the oxide coating, designs, patterns or images can be obtained, for example. Products created in this way can be used as labels, front plates, measuring sticks, power distribution images, traffic signs, identification cards, etc.

[Brief description of the invention]

coloring the oxide coating of aluminum or an aluminum alloy with an organic compound, introducing at least one diazo compound into the pores of the oxide coating and reacting with the formation of a dye by external action;
Alternatively, the diazo compound is reacted with at least one other organic compound introduced into the pores before or after the diazo compound.

By exposing the diazo compound introduced into the oxide coating, designs, patterns or images can be obtained, for example. Products created in this way can be used as labels, front plates, measuring sticks, power distribution images, traffic signs, identification cards, etc.

Claims (1)

[Scope of Claims] 1. A method for coloring an oxide film of aluminum or an aluminum alloy using an organic compound, which method involves introducing at least one kind of diazo compound into the pores of the oxide film, and dyeing by an external action. A process characterized in that it is reacted with at least one other organic compound introduced into the pores before or after the diazo compound. 2. The method according to claim 1, characterized in that the oxide film is obtained artificially. 3. A method according to claim 1, characterized in that the oxide coating treated by the method is then cleaned and/or sealed. 4. The method according to claim 1, in which the dye is treated with electromagnetic waves whose wavelength corresponds to or shorter than the infrared region before forming the dye. A method characterized by changing at least one dye-forming ability of the diazo compound. 5. The method according to claim 4, characterized in that the irradiation is carried out in the UV range. 6. The method according to claim 4, characterized in that the irradiation is carried out after the introduction of at least one diazo compound, but before the initiation of the reaction.