NL8103906A - METHOD FOR DYEING OXIDE LAYERS OF ALUMINUM OR ALUMINUM ALLOYS WITH ORGANIC COMPOUNDS - Google Patents

Description

r * i

Donate & Co. in Zug, Switzerland.

Process for painting oxide layers of aluminum or aluminum alloys with organic compounds.

The present invention relates to a method of dyeing oxide layers of aluminum or aluminum alloys with organic compounds.

Alumi-5 enum or aluminum alloys are often used for shields »shells» front plates, etc. · As a rule, the homogeneity and porosity of the artificially produced oxide layers are used. Dyes can be stored in the pores and the homogeneity guarantees a pure homogeneous appearance of the oxide layer. The pore openings can be closed by simple after-treatment (sealing). In addition, the oxide layer is treated, for example, with boiling water. In this treatment, the aluminum oxide usually absorbs water molecules in the crystal lattice and increases in volume, leading to closure of the pores. Since this process is generally irreversible, any dye stored in the pores is excellently protected.

To dye an oxide layer, it is generally contacted with the solution of the desired suitable dye and the latter allowed to settle. Other processes use, for example, colored metal oxides which are generated either during the oxidation of the aluminum or afterwards in the layer. However, methods are also known, for example, for evaporating the dyes in the layer.

Frequently, the paths being treated are to produce patterns in the layer, such as are generally used for shields. In general, two groups can be distinguished: the direct and the indirect method.

In the direct method, the dye usually thickened with a colloid is applied directly to the oxide layer, for example according to the offset or screen printing.

In the indirect method, as a rule, a scale is applied to the oxide layer, which covers the places not to be treated. In principle, one can proceed according to the positive or negative method, ie either cover the non-paintable areas and then apply the dye, or first color the entire layer and cover the areas to be colored and decolorize the rest. for example, by etching or destroying the dye. The application of the slabs 8103906 2 * * \ can also take place according to the offset * or screen printing *

By repeating the work flow, both methods - the direct as well as the Indirect, usually also multi-colored effects can be achieved. Combinations of both methods are generally possible.

Generally, the application of the dye or scabones is done by mechanical printing aids. However, since the latter usually require a printing form, such as, for example, a screen, offset printing plate, stamp, etc., the manufacture of which is quite expensive, the smaller photographic printing process is generally preferred.

For the indirect method, for example, a photoresist is used, the solubility of which is changed by the influence of light in certain solvents. For example, if an anodically oxidized aluminum plate coated therewith is exposed under a negative or positive and then washed with a suitable solvent, the washed places are exposed and can be colored. For the direct method, for example, the property of silver salts is used, after the action of light to be reduced by certain chemicals, and thus to provide a silver image. For example, methods are also known with other photosensitive metal salts.

For example, it is also known that various azo dyes are suitable for dyeing artificial oxide layers of aluminum. Azo-25 dyes generally form when diazo compounds are reacted with suitable organic compounds, so-called coupling agents.

On the other hand, the idea according to the invention is to produce these dyes.

A process has now been found for painting oxide layers of aluminum or aluminum alloys with organic compounds, characterized in that at least one diazo compound is introduced into pores of the oxide layer, which is introduced into the pores before or after the diazo compound to form a dye by external influences or with at least one other organic compound is reacted. Preferably, the oxide layers are produced artificially in the process of the invention. The oxide layers thus treated can subsequently be rinsed and / or post-compacted.

40 For the formation of the dye, the ability of at least one diazo compound in the oxide layer to form dyes can be formed by irradiation with electro-8103906 * Λ t 3 magnetic waves, the wavelength of which corresponds to or is shorter than the infrared range. be changed. The irradiation preferably takes place with waves from the UV range.

Usually, the irradiation takes place after the introduction of at least one diazo compound, but before the initiation of the reaction.

The preferred artificial oxide layers of aluminum or aluminum alloys can be produced by known methods. The direct current sulfuric acid process is preferred; 10 ie the so-called GS process. Generally, however, it is also possible to produce these oxide layers in other ways, such as, for example, with the sulfuric acid alternating process, the chromic acid process, the Ematal process or also an electroless process, etc.

Commercially available aluminum alloys or commercially available aluminum can be used in the process of the invention. Preferably, however, the quality suitable for anodic oxidation is used.

An example of diazo compounds which are used in the method according to the invention and which can be reacted with themselves, ie by external influences such as temperature increase, irradiation, change of the ρΞ value, action of a gas etc. and thereby a dye is the diazo compound of 1-amino-naphthol-3,6-disulfonic acid, the so-called H-acid.

However, it is also possible to use diazo compounds in the process according to the invention, which are changed during application on the oxide layer and form a dye.

However, the present invention also includes the possibility that at least one diazo compound introduced into the oxide layer is reacted with a so-called coupling agent to form a dye. Examples of suitable diazo compounds are products A, G, HC-1, Y, etc. from Kalle, Wiesbaden.

Examples of suitable coupling agents are products 1, 5, 13, 38 etc. from Kalle, Wiesbaden.

Any diazo compound and any so-called coupling agent can be used in the method according to the invention. Typically, commercially available diazo salts, such as those of the diazo type, for example, are reacted with the appropriate coupling agents for sale.

No limits are imposed on the concentrations of the diazo compounds and the coupling agents, for example in the form of aqueous solutions. Usually the selected concentration depends on the solubility of the diazo compound, respectively on the coupling agent, the desired color intensity, the resulting dye, the cost factor, etc.

In the case of photosensitive diazo compounds, it is generally advantageous to use dim light so that the diazo compounds are not changed.

Generally, the diazo compound is first introduced and then the coupling agent into the oxide layer; however, the reverse order is usually also possible.

Therefore, one of the two aforementioned components can be introduced into the oxide layer and the other component, for example as solution or gas, allowed to act from the outside, whereby the azo dye is then formed in the oxide layer.

Since coupling of the two components often takes place only in a certain pH range, it is also possible to layer both components if it is ensured that their pH value is outside the coupling range.

In this case, the dye is formed as soon as the pH value enters the coupling range due to external influences, for example an ammonia or hydrogen chloride atmosphere, etc. Usually the coupling takes place in the alkaline range. The reaction in the pores is usually instantaneous; however, in some cases the reaction may extend over a longer period of time.

For example, application of the components can be accomplished in the following manner. Apply with a cotton pad, immerse in solutions, spray on with spray guns, pour on with an infusion machine, roll up with a roller mill, etc.

Usually the process according to the invention is carried out at atmospheric pressure and ambient temperature. However, higher or lower temperatures can also be used.

* As indicated above, the treated oxide layer can also be rinsed. This generally has the advantage that the soluble constituents, which do not form the dye, are washed out and a subsequent reaction, such as darkening afterwards, or decomposition of the dye, etc., can be carried out therewith. be avoided.

As indicated above, the treated oxide layer can also be post-compacted. The advantage of a recompression generally consists in that the surface becomes insensitive to contamination and is protected against washing out of the color or colors 8103906> * i "5, because the gates are closed. can be achieved by introducing a wax, lacquering, ie by coating, impregnation with a water-repellent agent, for example a polysiloxane, treatment with boiling water, treatment with at least an aqueous solution of suitable chemical compounds, such as, for example, nickel acetate, cobalt acetate etc. Preferably the recompression takes place by treatment with boiling water.

An advantage of the present invention is that it is possible to coat the oxide layers with a component and by choosing the two-component it is possible to produce different colors in hand.

Another advantage is the possibility of producing insoluble ao dyes (pigments) in the oxide layer, which can prove to be a great advantage during further processing, for example resistance to weather influences, bleeding during sealing, etc.

Many diazo salts are generally photosensitive, i.e. they lose their ability to form azo dyes with coupling agents. This principle has long been applied, for example, in the diaoztypie.

A paper coated with a photosensitive diazo salt is usually exposed under a positive light and then reacted with a coupling agent.

As mentioned above, the ability of at least one diazo compound to form dyes in the oxide layer by irradiation with electromagnetic waves can be changed.

According to the present invention, if a suitable diazo salt is introduced into the oxide layer, exposed in full or in part to a positive and reacted with a coupling agent, then as a rule a colored image of the positive is produced, because in the exposed places the diazo salt is destroyed. and loses its ability to form azo dyes with coupling agents.

UV light is preferably used for the irradiation. Preferably, the irradiation uses actinic tubes, quartz lamps, arc lamps, xenon lamps or daylight as light sources.

There are usually no limits to the combination possibilities between the diazo compounds, the coupling agents and the irradiation; for example, it is possible to first store the diazo compound in the oxide layer, to change it with the irradiation in the desired manner and subsequently to react the compound thus obtained with the coupling agent. However, it is also possible to couple both 8103906

* A V

* 1 * 6 letting components into the oxide layer and then performing the irradiation * As mentioned above, many other color formation combination possibilities can be used in the process of the invention.

By irradiating the diazo compounds stored in the oxide layer, for example, patterns, signs or images can be produced. The products thus produced can be used as shields, front plates, trays, circuit diagrams, traffic signs, identity cards, etc.

The shelf life of these products manufactured by the method according to the invention corresponds at least with a normal Eloxal shield quality, but as a rule far exceeds this.

The present invention can be further illustrated by the following examples.

15 Example 1.

A pre-chemically matted aluminum or aluminum alloy plate suitable for decorative anodic oxidation was anodically oxidized according to the usual DC sulfuric acid process under the following conditions: 20 Electrolyte Sulfuric acid 180 g / l electrolyte

Aluminum 5-15 g / 1 electrolyte

Temperature 19-22 ° C

Current density 1.5 A / dm ^

Duration 30 min.

After the oxidation, the plate was post-treated in 15 to 20% nitric acid for 5 minutes, rinsed and dried.

A solution of real blue salt BB (diazotized 4-amino-2,5-diethoxy-benzanilide zinc double salt) was applied with a water drop. 10 g of acetic acid about 90% at 100 ml for one minute on the oxide layer. It was then allowed to dry and dried with a warm air apparatus. A positive was placed on the plate and exposed from a distance of 60 cm with a quartz lamp for 30 seconds.

The exposed plate was dissolved in a solution of Floroglucinol 5 g

Distilled water at 100 ml

Dip ammonia solution 25% at pH 10. The image immediately appeared as black-brown on light under-40 ground. The plate was then rinsed thoroughly with water and subjected to the conventional sealing with water of 96 to 100 ° C for 30 minutes.

Example 2.

A plate was treated according to example 1, but after exposure it was immersed in the following solution: 2,3-Naphthoic acid morpholinopropylamide 3 g (Kalle, Wiesbaden: coupling agent 38)

Water distilled at 100 ml

Ammonia solution 25% at pH 10.

10 A violet image immediately appeared, which after the subsequent water treatment and recompression slightly lost its red hue in favor of blue.

Example 3.

A plate anodically oxidized according to example 1 was coated with the following solution: • 4-Diazodimethylaniline zinc chloride 5 g (Firma Kalle, Wiesbaden: diazo A)

Hexyl resorcinol 5 g

Acetic acid approx. 90% 30 g 20 Methanol at approx. 100 ml.

After 30 seconds, the plate was rubbed dry with a dry water drop. The exposure took place under a positive as described in example 1. The exposed plate was covered with blotting paper impregnated with the following solution and then dried well.

Ammonium hydrogen carbonate 10 g

Polyvinyl alcohol (M4 / 88 Hoechst) as 10% ethanol solution 1 ml 30 Ammonia solution 25% 20 ml

Distilled water at 100 ml.

The whole was compressed for 20 seconds with a heating plate heated to about 120 ° C (for example iron). The image was developed dark brown, however, upon subsequent rinsing, it took on a khaki brown color, which it retained even after post-densification.

Example 4.

A plate pre-treated and anodically oxidized according to example 1 was poured with the following solution: 8103906 KV # 8 2,4,2 ', 4'-Tetraoxydiphenyl sulfide 4 g (Firma Kalle, Wiesbaden: coupling agent 2) 4-diazo-2-methylphenylpyrrolidone ZnCl2 6 g (Firma Kalle, Wiesbaden: Diazo Y) 5 Thiourea 4 g

Acetic acid approx. 90% 5 ml

NaHS03 “Solution in methanol saturated 5 ml

Butylglycol 15 ml

Methanol at 100 ml.

After drying, exposure was done as in example 1, but the exposure time was 1 minute instead of 30 seconds. Then the exposed plate was subjected to a heat treatment of 140 ° C for 1 minute. A dark brown image was created, which was also not changed by the subsequent rinsing and post-compaction.

15 Example 5.

An anodically oxidized, unsealed plate with an oxide layer thickness of at least 18 µm was sprayed with the following solution: 4-Diazo-2,5-diethoxyphenylmorpholine \ ZnCl2 10 g (Firma Kalle, Wiesbaden: Diazo HC) 20 distilled water at 100 ml.

After drying, an acetate foil was placed on it, which was poured onto the plate side with the following solution and then dried: β-Naphthylamine 5 g 25 Urea 10 g

Ethyl cellulose solution 10% in ethanol 15 ml

Butylglycol 15 ml

Methanol at 100 ml

Compression with a heating plate 30 (for example iron) heated to 120 ° C for 20 seconds resulted in an orange color in the layer, which also remained unchanged during subsequent rinsing and post-compaction.

Example 6.

An anodically oxidized, unsealed plate with an oxide layer thickness of at least 15 µm was covered with the following solution for 1 minute (water drop): 4-Diazo-diethylaniline ZnCl2 10 g (Firma Kalle, Wiesbaden: Diazo C)

Urea 5 g 40 Distilled water at 100 ml.

8103906 ·. ^ 0 9

Then it was leveled with a sharp sharpened rubber scraper and dried. After the exposure, the plate was covered with an acetate foil, which was prepared on the side facing the plate in the following manner: 5 poured with the following solution: 1,8-Naphthylenediamine 5 g

Ethyl cellulose solution 10% in ethanol 15 ml

Butylglycol 10 ml

Methanol at 1100 ml 10 and dried well. A 130 ° C hot heating plate (e.g. iron) was pressed on the foil for 20 seconds. The image developed red in the unexposed places. This color also remained unchanged during the subsequent rinsing with water and the recompression.

15 Example 7.

A plate was treated as in Example 6, however, instead of the film of Example 6, a piece of film from Example 5 was used which had not yet been subjected to the heat treatment. An orange image arose, that all after-treatments survived undamaged.

Example 8.

A plate pretreated and anodically oxidized according to Example 1 was covered with a solution of the following composition for 1 minute: 4-Diazodiethylaniline ZnCl 10 g 2,5-Dimethyl-4-dimethylaminomethylphenol-HCl (Firma Kalle, Wiesbaden: coupling agent 13) 6 g

Adipic acid 1 g

Distilled water at 100 ml 30 and then rubbed dry with a dry water drop. After exposure under a positive (according to example 1), the plate was placed in a closed reservoir, in which a 25% ammonia solution evaporated in an open dish. The evaporated ammonia gas shifted the pH value of the diazo coupling agent mixture to the coupling range (from acid 35 to alkaline). A yellow copy of the positive appeared in a short time. After 5 minutes, the plate was taken out of the reservoir, rinsed and sealed.

Example 9.

An anodically oxidized, unsealed sheet with an oxide layer-40 thickness of at least 15 µm was added at least 1,8103906 w with the following solution.

<V

10 minutes covered: 4-Diazodimethylaniline zinc double salt 2 g (Firma Kalle, Wiesbaden: Diazo A)

Sodium salt of 2,7-dioxynaphthalene-3,6-dlsulfonic acid 4 g 5 (Firma Kalle, coupling agent 5)

Distilled water at 100 ml and then leveled with a sharp rubber scraper and dried. According to example 8, exposure and development were performed.

After developing in the ammonia atmosphere, the copy of the 10 was positive blue; after sealing violet.

Example 10.

The sheet was treated according to Example 8, but again coated and processed at the end instead of the seal of Example 9. The shield was then tricolor. After sealing, the colors were yellow (solution of example 8), violet (example 9) and light brown (in those places where the two colors overlapped).

8103906

Claims (6)

Method for painting oxide layers of aluminum or aluminum alloys with organic compounds, characterized in that at least one diazo compound is introduced into the pores of the oxide layer and this is formed by a dye by external influences or with at least another organic compound introduced into the pores before or after the diazo compound. 2. Process according to claim 1, characterized in that the oxide layers are created artificially. Process according to claim 1, characterized in that the oxide layer thus treated is subsequently rinsed and / or post-compacted (sealing). 4. A method according to claim 1, characterized in that for the formation of the dye by irradiation with electromagnetic waves, the wavelengths of which correspond to the infrared range or are shorter, the ability of at least one diazo compound in the oxide layer is to dyes changes. Method according to claim 4, characterized in that the irradiation is carried out in the UV range. Process according to claim 4, characterized in that the irradiation is carried out after the addition of at least one diazo compound, but before the initiation of the reaction. 8103906