FR2489849A1 - PROCESS FOR COLORING ALUMINUM OXIDE OR ALUMINUM ALLOY LAYERS USING ORGANIC COMPOUNDS - Google Patents

Abstract

THE INVENTION RELATES TO A PROCESS FOR COLORING ALUMINUM OR ALUMINUM ALLOY OXIDE LAYERS WITH ORGANIC COMPOUNDS. IN THE PORES OF THE OXIDE LAYER, AT LEAST ONE DIAZOIC COMPOUND IS INTRODUCED AND IT IS REACTED, WITH THE FORMATION OF A COLORANT, UNDER THE EFFECT OF EXTERNAL INFLUENCES OR WITH AT LEAST ONE OTHER ORGANIC COMPOUND, WHICH HAS BEEN INTRODUCED INTO PORES BEFORE OR AFTER DIAZOIC COMPOUND. IRRADIATION OF DIAZOIC COMPOUNDS INTRODUCED IN THE OXIDE LAYER MAKES DRAWINGS, SIGNS OR IMAGES BEING OBTAINED. APPLICATION TO THE MANUFACTURE OF SIGNAGE PLATES, FRONT PANELS, LADDERS, ETC.

Description

Process for coloring aluminum oxide layers or

  of aluminum alloys using organic compounds.

  The present invention relates to a method for coloring aluminum oxide or aluminum alloy layers with organic compounds.

  Aluminum or aluminum alloys are often used

  to make nameplates, ladders,

  the, front panels, etc. For this purpose, the homogeneity and porosity of the artificially produced oxide layers is generally used. We can introduce materials

  dyes in the pores and homogeneity guarantees a

  this unitary clean of the colored oxide layer. A simple after-treatment called "sealing" makes it possible to close the openings of the pores. For this purpose, for example, the oxide layer is treated with boiling water. During this treatment, aluminum oxide

  normally absorbs water molecules in its crystal network

  tallin and its volume increases, which causes the closing of pores. Since, in general, this process is irreversible, the coloring material that may be housed in the pores is

perfectly protected.

  To color an oxide layer, it is generally brought into contact with a solution of the desired colorant and allowed to absorb. Other processes use, for example, colored metal oxides which are formed either during the oxidation of aluminum or subsequently in the layer. However, for example, methods are also known; depositing dyestuffs by evaporation

in the layer.

  There are many ways to form a drawing in

  the layer, as is generally necessary for

  signs. Basically we can separate them into two groups:

  the direct method and the indirect method.

  In the indirect method, a cache is generally placed on the oxide layer which covers the places not to be treated. We can then proceed fundamentally according to the positive or negative process, that is to say, to cover the places not to be colored and then to deposit the color, or to color the whole layer first and to cover the places that must remain colored and remove the color of the

  remain, for example by chemical attack or destruction of the

  coloring matter. The setting up of the cache can also be

  do, for example, by the method of flexography or

  graphy. The repetition of these operating phases makes it possible with both direct and indirect methods to obtain normal

  effects of several colors. Combinations of both methods

are usually possible.

  In general, the color or the cover is placed using mechanical auxiliary means. However, since most of the time these require a 4'impjession organ,

  such as a screen printing screen, a printing plate,

  offsett, a hallmark, etc., the manufacture of which is very

  costly, for small series we generally prefer the

surrendered photographic printing.

  For the indirect method is used for example a photolaque whose solubility in specific solvents is changed under the action of light. If, for example, an anodically oxidized aluminum plate covered by this oxide is illuminated, with the interposition of a positive or a negative, and then washed with an appropriate solvent, the places where the lacquer has disappeared are free. and can be colored. For the direct method, for example, the property of salts of ageert to be reduced by certain agents and after the action of its light, and thus to provide an imaginary, is also known. other methods with, for example, other

photosensitive metal salts.

  It is also known to use, for example, various azo dyes for coloring artificial aluminum oxide layers. In general, azo dyes are obtained by

  reacting diazo compounds with organic compounds

  appropriate, called copulants.

  The invention aims at a new way of forming these

dyes.

  The invention relates to a process for coloring aluminum oxide or aluminum alloy layers with organic compounds, which is characterized in that in the pores of the oxide layer, introduces at least one diazo compound and reacts it with formation of a dye,

  under the influence of external influences or with at least one

  organic compound, which has been introduced into the pores before or after the diazo compound. Preferably, the layers

  in the process according to the invention are formed by

  cially. The oxide layers thus treated can still

  then be washed and / or densified.

  Prior to dye formation, the ability of at least one diazo compound to be formed in the dye oxide layer can be modified by irradiation using electromagnetic waves whose corresponding wavelengths

  are shorter than those in the infrared range.

  The irradiation is preferably carried out with waves of

range of ultraviolet.

  In the usual way, the irradiation takes place after the introduction

  duction of at least one diazo compound but before the start of

the reaction.

  The layers of aluminum oxide or aluminum alloys

  Preferred artificial materials can be formed by

  surrendered known. The sulfuric acid process is preferred in

  continuous stream, that is to say the so-called GS process. However, in

  neral it is also possible to form these oxide layers in another way, for example according to the acid process

  sulfuric acid, the chromic acid process

  that the so-called "Ematal" process or a process without electricity, etc. According to the process of the invention it is possible to use aluminum alloys or aluminum alloys available in the

trade.

  However, preferably the appropriate quality is used.

anodic oxidation.

  An example of disazo compounds that can be used

  in the process according to the invention and which can be

  react with themselves, that is, under the influence of

  such externalities as temperature increase, irradiation, pH change, action of a gas, etc., which thereby form a dye, is the diazo compound of 1-amino acid. However, according to the process of the invention, it is also possible to use diazo compounds which change during their deposition on the oxide layer and form a dye. The present invention, however, also includes the possibility of reacting at least one diazo compound

  introduced into the oxide layer with a compound

  lant, which forms a dye. Examples of suitable diazo compounds are the products "A, C, HC-1,4",

  etc. of the Kalle Company, Wiesbaden.

  Examples of suitable couplers are the products

  so-called "1, 5, 13, 38", etc. of the Kalle Company, Wiesbaden.

  According to the process of the invention it is possible to use any diazo compound and any coupler. Normally, commercially available diazo salts, such as those used, for example, in diazotype, are reacted with the appropriate couplers sold in the process.

trade.

  No limit is imposed on the concentration of the diazo compounds and couplers, for example in the form of aqueous solutions. Usually, the

  concentration chosen depends on the solubility of the diazol

  that and respectively the coupler, the desired color intensity, the dye formed, the cost factor, etc. In the case of photosensitive diazo compounds, it is generally advantageous to work with filtered light

  so that the diazo compounds are not modified.

  In general, the diazo compound and then the coupler are first introduced into the oxide layer; normally

  however, it is possible to proceed inversely.

  Therefore, one of the two

  in the oxide layer and let the other component, for example in the form of a solution or a gas, act from the outside, the azo dye forming then

in the oxide layer.

  Since the reaction between the two components often takes place only in certain pH ranges, the two components can also be introduced into the layer if their pH is not in the reaction range. . In this case, the dye is formed as soon as the pH is

  brought into the reaction range under the influence of external influences.

  with, for example, an atmosphere of ammonia or hydrochloric gas. Usually the reaction proceeds in the alkaline range. Normally the reaction in the pores LQ- is carried out instantaneously; however in some cases she

  t. X may unwind over a longer time interval.

  The deposit of components can for example be made

  following ways, using a cotton wool pad, immers-

  in solutions, spraying with a spray gun

  sprayer, pouring with a pouring device, application

  roll with an applicator, etc. Normally the method according to the invention is set

  work at atmospheric pressure and at room temperature.

  However, it is also possible to use higher temperatures

  higher or lower depending on the case.

  As seen above, the treated oxide layer can also be washed. This in general has the advantage that the soluble constituents, which do not form the dye, are removed by washing and can be avoided.

  this way a further reaction, such as a darkening

  the dye, etc. As also seen above, the oxide layer

  treated can also be densified. The advantage of densification

  cation is generally that the surface is insensitive to

  dirt and is protected from color or color removal when washed, as the pores are closed. Densification can be done by

  example by applying wax, lacquering, that is to say, protecting

  by lacquer, impregnation with a hydrophobic product, for example silicone, treatment with boiling water, treatment with at least one aqueous solution of suitable chemical compounds, for example nickel acetate, cobalt acetate, etc. Preferably the densification is

done in hot water.

  An advantage of the present invention lies in the fact that the oxide layers of a component can be covered

  and obtain different colors by choosing the second

  we apply. Another advantage lies in the possibility of forming insoluble azo dyes in the oxide layer.

  (pigments), which can be very advantageous when

  later, for example for weather resistance, dye migration during sealing, etc. - -Noubreui sea '4-azo. . And so are the generalities, that is to say that under action: from your light

  - their ability to form eagle water with p - -

  This application is being applied from $ to $ exepl_

  ": '' $ 5; o, -. 'Tpl,". AT:.'-......: '. - :.

  Paper coated with photosensitive diazolic salt

  is usually lit up with the interposition of a positive -, -

  then it is reacted with a coupler.

  As already seen above, the irradiation using electromagnetic waves makes it possible to modify the aptitude

  at least one compound -diazoIque- in the oxide layer - form-- -X-

dyes.

  If, according to the present invention, a diazo salt

  is introduced into the partially illuminated oxide layer.

  completely or completely with the interposition of a slide, and

  reacted with a copulant, it usually appears as a reproduction

  coloring of the slide, because in lit places the diazo salt has been destroyed and has lost its ability

  to form azo dyes with couplers.

  For irradiation, preference is

  ultraviolet light. For irradiation, preference is

  as a light source for actinic tubes, quartz lamps, arc lamps, xenon lamps or

of the day.

  No limit is imposed on the possibilities of combinations between diazo compounds, couplers and irradiation; it is thus possible, for example, first to introduce the diazo compound into the oxide layer, to modify it in a desired manner with the aid of the irradiation,

  then allowing the compound thus obtained to react with the coupler.

  However, it is also possible to introduce the two

  in the oxide layer and then irradiate them. As men-

  As mentioned above, many other combination possibilities can be used to obtain the following coloring.

the process of the invention.

  The irradiation of the diazo compounds introduced into the oxide layer makes it possible to form, for example, drawings, signs or images. The products thus manufactured can be

  used as nameplates, front panels,

  the, connection diagrams, road signs, identity cards, etc. The durability of these products manufactured with the process according to the invention corresponds at least to that of a quality

  anodized for nameplates, but the exceeding

is often from far away.

  The present invention will be better understood by means of

  the following description of the following non-limiting examples.

EXAMPLE 1

  A sheet of aluminum or aluminum alloy,

  made by chemical means, which is suitable for the oxidation of

  decorative anodic dation, is oxidized anodically according to the conventional dc sulfuric acid process, under the following conditions: - Electrolyte Sulfuric acid 180 g / l electrolyte Aluminum 5-15 g / l electrolyte - Temperature 19- 22aC - Current density 1.5 A / dm2

- Duration 30 minutes.

  After the oxidation the sheet was treated 5 minutes in

  15.20% nitric acid, washed and dried.

  With the aid of a cotton ball, a solution consisting of - solid blue salt BB (double salt

of 4-amino-2,5-diethoxybenza-

  nilide and diazotized zinc) 10 g - about 90% acetic acid up to 100 ml, for 1 minute on the oxide layer. We then leave

  dry and complete the drying with a hot air apparatus.

  Put a slide on the sheet and light up

  60 cm with a quartz lamp for 30 seconds.

  The lit sheet is immersed in a constitutional solution

  killed by - phloroglucine 5 g - distilled water up to 100 ml

  - 25% ammonia solution up to pH 10.

  The image is immediately formed in dark brown on a light background.

  The sheet is then carefully washed with water and subjected to the usual densification ("sealing") with hot water to

96-100 C, for 30 minutes.

EXAMPLE 2

  A treated sheet is dipped according to Example 1, but after being illuminated, into the following solution: morpholinopropylamide 3 g of 2,3-naphthoic acid (Kalle Company, Wiesbaden: coupling agent 38) - distilled water 100 ml

  - 25% ammonia solution up to pH 10.

  It immediately appears a purple image which, after the passage to the water and the "sealing", loses some of its red color

in favor of blue.

EXAMPLE 3

  Anodically oxidized sheet according to Example 1 is coated with the following solution: - zinc chloride and 4-diazo-demethylaniline ("Diazo A" Kalle Company, Wiesbaden) 5 g - hexyl resorcinol 5 g - acetic acid about 90% 30 g

  methyl alcohol up to about 100 ml.

  After 30 seconds the sheet is rubbed with a buffer

  dry cotton wool to dry. Illumination is done with interpolation

  The illuminated plate is covered with a blotting paper impregnated with the following solution: ammonium carbonate 10 g - polyvinyl alcohol ("M4 / 88") Hoechst) in the form of 10% solution in ethanol 1 ml - 25% ammonia solution 20 ml - distilled water up to 100 ml,

then well dried.

  Everything is pressed for 20 seconds with a plate

  Heating up to about 120 ° C (for example, a meal-iron

  ser). The image develops dark brown, but it takes

  in a khaki-brown color after washing, which is

also after the "sealing".

EXAMPLE 4

  It is poured onto anodized and pre-oxidized

  treated in accordance with Example 1, the following solution:

2,4,2 ', 4'-tetraoxydesulfide

  diphenyl ("Copolymer 2" from Kalle Company, Wiesbaden) 4 g

- Zn chloride and 4-diazo

  methyl-phenyl-pyrrolidine ("Diazo 4 from Kalle, Wiesbaden) 6 g - thiourea 4 g - about 90% acetic acid 5 ml - solution of NaHSO3 in saturated methanol 5 ml - butyl glycol 15 ml

- methanol up to 100 ml.

  After drying, the sheet is illuminated as in the example

  ple 1, but for a duration of 1 minute instead of 30 seconds.

  Then the lit sheet is subjected to a heat treatment of one minute at 140 C. A dark brown image appears which does not

  does not change during washing and "sealing".

EXAMPLE 5

  An anodically oxidized, non-densified sheet with an oxide layer of at least 18 w, is spray-dried with the following solution: if -> V: A - -Z), a-qZtc- t '<G

-: --- - -

4-diazo-2,5-diethoxy

  phenylmorpholine-1/2 ZnCl 2 ("Diazo HCI from Kalle, Wiesbaden) 10o g - distilled water up to 100 ml After drying, an acetate sheet is placed thereon

  on the side of the sheet, the following solution was

  before drying it: - e-naphthylamine 5 g - urea 10 g - 10% ethylcellulose solution in ethanol 15 ml - butyl glycol 15 ml

- methanol up to 100 ml.

  Pressing with a hot plate raised to 120 C

  (for example an iron) for 20 seconds, it will

  lopped an orange color in the layer, which does not change

  during subsequent washing and sealing.

EXAMPLE 6

  An anodically oxidized non-densified sheet with an oxide layer of at least 15% is coated for one minute (with a cotton ball) with the following solution:

- - Zn chloride and 4-diazo

  diethylaniline ("Diazo C" from the company Kalle, Wiesbaden) 10 g - urea 5 g

distilled water up to 100 ml.

  Then scrape with a sharp rubber squeegee and dry. After illumination the sheet is covered with an acetate sheet whose side facing the sheet has been prepared by pouring on the following solution: - 1,8-naphthylenediamine 5 g - solution of ethylcellulose at 10% in ethanol 15 ml - butyl glycol 10 ml - methanol - up to 100 ml, and allowed to dry well. On the sheet is pressed for seconds a heating plate heated to 130 C (for example an iron). The image grows red in unlit areas. This color does not change after washing

and subsequent "sealing".

EXAMPLE 7

  A sheet is treated as in example 6 but instead of the sheet of example 6 is used a piece of the

  sheet of example 5, which has not yet been submitted to

  thermal energy. It appears an orange image that supports all

  subsequent treatments without deterioration.

EXAMPLE 8

  An anodically oxidized sheet previously treated as in Example 1 is coated for 1 minute with the following solution:

- Zn chloride and 4-diazo

diethylaniline 10 g

2,5-dimethyl-4-dimethylamino

  methylphenol-HCl ("Copolymer 13" from Kalle, Wiesbaden) 6 g adipic acid 1 g - distilled water up to 100 ml,

  then rub it to dry with a dry cotton ball.

  After illumination with interposition of a slide (

  In Example 1, the sheet is placed in a closed vessel in which a 25% ammonia solution placed in a dish is evaporated. The ammonia gas that evaporates shifts the pH of the diazo-couplant mixture to the reaction range (from acid to alkali). It appears in a short time a yellow reproduction of the slide. After 5 minutes, the sheet is removed

  of the container, washed and subjected to "sealing".

EXAMPLE 9

  An anodically undensified oxidized sheet with an oxide layer of at least 15% is coated at least 1 minute with the following solution:

- double salt of zinc and 4-

  diazo-dimethylaniline ("Diazo A" from Kalle, Wiesbaden) 2 g

12 2489849

- sodium salt of 2,7-

  3,6-dioxynaphthalene disulfonic acid ("Copolymer 5" from the company Kalle, Wiesbaden) 4 g - distilled water up to 100 ml, then scraped with a sharp rubber squeegee and dried. The sheet is illuminated and developed according to Example 8. After development in the ammonia atmosphere, the reproduction of the image is blue, after the "sealing" it is purple.

EXAMPLE 10

  A sheet is treated according to Example 8 but at the end instead of the "sealing" according to Example 9, it is coated and

  treats again. The image obtained is of three colors.

  After the "sealing" the colors are yellow (solution of the example

  ple 8), violet (example 9) and light brown (in places o

the two colors are superimposed.

  Of course, the invention is not limited to the embodiments of the examples described, it is capable of numerous variants accessible to those skilled in the art, depending on the intended applications and without departing from the scope

of the invention.

-: <t f 0 ---:

Claims (6)

  1. Process for coloring aluminum oxide layers   or aluminum alloys using organic compounds,   characterized in that, in the pores of the oxide layer, at least one diazo compound is introduced and reacted,   with dye formation, under the influence of external influences   with at least one other organic compound, which has been   introduced into the pores before or after the diazo compound.   2. Method according to claim 1, characterized in   that the oxide layers are artificially formed.   3. Process according to claim 1, characterized in that the oxide layer thus treated is then washed and / or densified. 4. Process according to claim 1, characterized in that prior to the formation of the dye by irradiation using   electromagnetic waves, whose corresponding wavelengths   or shorter than those in the infrared range.   the ability of at least one diazo compound to change   in the oxide layer to form dyes.   5. Process according to claim 4, characterized in   that the irradiation is done in the range of ultraviolet.   6. Process according to claim 4, characterized in that the irradiation takes place after the introduction of at least   a diazo compound, but before the start of the reaction.