DE2052727A1 - Process for coloring anodized aluminum - Google Patents

Description

PATENT ANWXtTE

DR.-INQ. H. FINCKE
DIPL.-INQ. H. BOHR
DIPL.-1NG. S. STAEGER 2052727

fmr no «Ii * Ϊ6« 0 40

Folder 22413 - Dr. K
Case MD.22289

Imperial Chemical Industries Limited, London, Great Britain

"Process for coloring anodized aluminum ¹ *

Priority: October 27, 1969 - Great Britain

The invention relates to a method for dyeing anodi «. sized aluminum.

It is well known that aluminum, for example as Construction material used for buildings is intended to be treated to produce a layer of aluminum oxide on the aluminum surface, and then to color the aluminum to improve the appearance. A common method for producing the aluminum oxide rail is to use the aluminum as the anode in an electrolytic direct current cell, in particular in one in which the electrolyte is made up of dilute sulfuric acid or chromic acid, lead or steel being used as the cathode. Another electrolytic method of manufacture The aluminum oxide layer consists in using the aluminum as an anode in one electrolytically ««! Cell to use in which the electrolyte Oxalic acid, where the cathode is carbon, iron,

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Bid or stainless steel is used. The latter electrolytic Cells can be operated using direct current or alternating current.

The material made by the above electrolytic processes is commonly referred to as anodized aluminum. This designation is also chosen here.

The dyeing of anodized aluminum is normally carried out immediately after the anodizing treatment and consists in immersing the anodized aluminum in an aqueous dye bath at a temperature of up to 100 ° C. without drying it beforehand; however, the temperature is usually 50 to 65 ^° C. The dyeing process is brought to an end by bringing the anodized aluminum into contact with steam or in boiling water, in a heated solution of one or more metal salts, such as nickel acetate or cobalt acetate. or immersed in a solution of lanolin. These treatments have the effect of sealing the surface of the anodized aluminum.

However, the dyes with the best colors and lightfastness properties are not sufficiently soluble in water to be applied by this method. It was therefore proposed in Recently Tent to color anodized aluminum with acetone-soluble dyes from an acetone-based dye bath and not water-based, so that water-insoluble dyes can be used which have a high degree of weatherability . In this acetone-based dyeing process, the dyebath is used at room temperature and, preferably, a subsequent treatment is also used to seal the surface of the anodized aluminum.

It has now been found that freshly anodized aluminum can be effectively colored from a dye bath containing a halogenated ββ and preferably chlorinated hydrocarbon solvent. ΐν :;

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Oeaäfi of the invention is "omit a process for coloring anodized" Proposed aluminum, which is carried out by immersing freshly anodized aluminum in a dye bath, which consists of a boiling solution or dispersion of a dye consists in a halogenated hydrocarbon solvent.

Dyes insoluble in Ib halogenated hydrocarbon solvents can be dispersed in the solvent, and in particular an aqueous solution of the dye in the solvent dispersed (or emulsified). So not only dyes can be used that are in the halogenated hydrocarbon solvent are soluble, but also those that are in the halogenated hydrocarbon solvent are insoluble. All dyes can be used that are common to the usual aqueous dyeing process are useful (although the concentration of the dye is appropriate the dye used in each case may be different), which also applies to all dyes that are used in the known dyeing process Acetone base can be used and which are at least partially soluble in the halogenated hydrocarbon solvent.

The anodized aluminum freshly removed from the anodizing treatment is rinsed with water after the anodizing treatment and preferably also dried before or at the same time as the dyeing process according to the invention. Drying can be done as with the known ones Acetone-based processes can be carried out with the aid of dry warm air, but one particularly has been found to be Appropriate drying process for joint use with the dyeing process according to the invention from a drying process consists, in which a drying agent based on a halogenated Hydrocarbon solvent is used - examples for drying agents based on halogenated hydrocarbons solvents that can be used are solutions of cationic surfactants in trichlorethylene, as described in British Patent 835-0-2. alternative Desiccant based on halogenated carbon

109819/1782 _ h .

Hydrogen solvents are solutions of a sodium, ammonium or Amine salt of a monosulfonic acid derivative of a diester of a Succinic acid in a fluorochlorohydrocarbon solvent, as described in British Patent 1,157,190 is; Solutions of an amine salt of undecyl or tridecyl benzene sulfonic acid in a fluorochlorohydrocarbon solvent, as described in German patent application P 19 37 272 “6 is; Solutions of a metal, ammonium or amine salt of the monosulfonic acid derivative of a diester of a succinic acid in a chlorohydrocarbon solvent, as in the German one Patent application P 20 21 I06.7 is described; and solutions of a metal, ammonium or amine salt of an alkylbenzene sulfonic acid, wherein the alkyl group contains 7 to 14 carbon atoms, as described in the German patent application

According to the invention, a method for coloring anodized aluminum is also proposed in which.

freshly anodized aluminum is dried in that it is immersed in a desiccant containing a halogenated tea hydrocarbon solvent. Appropriate catfish is the halogenated hydrocarbon solvent of the drying composition the same solvent as the halogenated hydrocarbon solvent the dye composition.

The drying treatment according to the invention can be carried out as a separate step between the anodizing treatment and the coloring treatment be switched on. However, it has all been found particularly advantageous the freshly anodized aluminum after rinsing into a drying composition based on a halogenated hydrocarbon Solvent, in which the dye is incorporated has been immersed.

Thus, according to the invention, there is still a method of dyeing proposed by anodized aluminum, which

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is performed by dipping freshly anodized and rinsed aluminum in a composition comprising a halogenated-tss hydrocarbon solvent, a surface active agent and a Contains dye.

The amount of the dye may depend on whether the dyeing treatment and the drying treatment are carried out separately or together. In the case where the coloring treatment is carried out as a separate treatment following a drying process, the amount of dye is usually 0.01 to 5 »0 wt -.% And in particular about 0.1 wt -.%, Based on the halogenated hydrocarbon solvents. In dem.Fall, in which the dyeing treatment leads out simultaneously with the Trocknungsbshandlung is, the amount of dye wLederum is 0.01 BLS $, 0 wt -.%, Based on the halogenated hydrocarbon solvent, amount, but in this case, is the preferred gräfler amount than 0.1 wt. -I and it is especially approximately 0.2 wt .- # "in the case in which an emulsion of the dye used in the halogenlerten hydrocarbon solvent, the colorant easily causes a separation of the phases of the emulsion, and for this reason it is preferred to use low concentrations of the dye, such as about 0.2 wt.%, in such emulsions. In the event that the powder bath is also to be used to dry the anodized aluminum, the amount of surfactant in the dye bath is usually only low, such as about 0.02 wt. #, But larger amounts of this agent such as e.g. up to 2, wt .- #, be present. It has been found that the surfactant competes with the dye for the active sites on the anodized aluminum, and for this reason it is preferred to use the minimum amount of surfactant that still allows sufficient emulsification of the dye and effective drying (if appropriate ) of the anodized aluminum.

.. 6-109819/1782

The halogenated hydrocarbon solvent boils at least when used in a hot tub. Frichloroafchylori or perchloroethylene are preferred solvents, although the present invention is not limited with respect to the halogenated hydrocarbon solvents that can be used. Examples of other solvents that can be used are 1,1,1-trichloroethane, 1, 1, 2-trichloro-1, 2 _p 2, -trifluoroethane and methylene chloride. The solvent will usually contain stabilizing additives to inhibit its degradation.

The time during which the anodized aluminum is immersed in the dye baa is not critical, but is usually at least 10 minutes. In the case of a certain anodizing aiurriiiiujn, the depth of hue obtained generally increases with the time of immersion in the dyebath. Other criteria that affect the depth of the dye are the concentration of the dye in the dye bath and the thickness of the aluminum oxide layer and the amount of surfactant .

After the anodized aluminum has been colored in accordance with the invention, it is usually rinsed in a boiling halogenated hydrocarbon solvent (which is usually the same solvent as was used in the dye bath). For example, immersing the colored material in boiling solvent for 10 minutes is sufficient to seal the surface and it has been found that there is no need to subsequently immerse the colored material in boiling water or steam, although such treatment may of course be included can be.

The dyeing process according to the invention has the advantage over conventional aqueous dyeing processes that it is application of both water-insoluble dyes and water-soluble dyes allowed on anodized aluminum (where the same the weathering properties of the colored material

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be sert) and that there is the need for a subsequent sealing treatment with, for example, boiling water or avoids using steam. The process has the advantage over the known acetone-based dyeing process that a non-flammable solvent with low toxicity is used, and that in the preferred embodiment there is also a need for a separate drying stage. Here too will avoiding the need for a sealing treatment in hot water or steam "was usually present in one process Acetone base is carried out.

Anodized aluminum is produced by the method according to the invention colored in uniform shades, and the color is opposite to rubbing and washing in hot and cold water, acetone or boiling trichlorethylene resistant. The colored material can be in used in any case where anodized aluminum is commonly used is used.

The invention is illustrated in more detail by the following examples.

Example 1

A plate made of essentially pure aluminum with the dimensions 50 χ 100 mm was connected as an anode in an electrolytic DC cell which had a lead cathode and contained 15% (V / V) sulfuric acid as the electrolyte. The cell was kept at 20 ⁰ C, and a voltage of 15 volts was applied to the electrodes during a tent space of 40 minutes.

The resulting anodized aluminum plate was then placed in clean « rinsed with cold water, whereupon it was dried by placing it in a boiling solution of cetylpyridinium bromide in triohlorolthylen was immersed. After drying, the plate was 10 minutes in a boiling solution (0.1 * j (w / w)) of waxoline Red 0 Dyestuff (CI. 26105) in a commercially available stabilizing

109619M782 ' ⁸ '

ten trichlorethylene immersed. The colored anodized aluminum was finally rinsed in clean boiling trichlorethylene for 10 minutes to remove excess non-adsorbed dye remove.

The anodized aluminum was an even orange Dyed hue and was completely free of stains and streaks. By rubbing the colored plate with various solvents, such as hot and cold water, acetone and trichlorethylene, the orange color could neither be removed nor the hue to be changed.

Example 2

A plate of essentially pure aluminum was anodized as in Example 1 and then rinsed in clean cold water. The resulting wet anodized aluminum was immersed for 10 minutes in a boiling solution containing 0.075 % (w / w) Ce ty 1 -pyridinium- br omid and 0.2 <jd (w / w) Waxoline Red 0 Dyestuff in a commercially available stabilized trichlorethylene. The water on the anodized aluminum was removed in the form of a constant boiling mixture with trichlorethylene. The vapors obtained were condensed and the condensate was separated in a heavy weight separator to recover the trichlorethylene. The colored anodized aluminum was then rinsed in clean boiling trichlorethylene for 10 minutes to remove any residual traces of cetyl pyridinium bromide and any unadsorbed dye. The results were identical to the results of Example 1.

Example 3

The procedure of Example 2 was repeated, with the difference that 0.1 % (w / w) sodium di (methylamyl) "sulfosuccinate was used instead of the 0.075 % " 0 / w) cetylpyridinium bromide and that the The concentration of waxoline Red 0 was reduced to 0.1 t {Q / g) .

The results were the same as in Example 1.

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Examples 4 - 26

The procedure of Example 2 was used to prepare freshly anodized To dye aluminum using the dye baths given in Table 1 below. Every time it tried, it became Aluminum is colored to a uniform shade by rubbing not changed with hot or cold water, hot or cold acetone, or hot or cold halogenated hydrocarbons could be.

Table 1

Ex.
No. solvent *
dye
(0.2 #, G / G) C. Color
index - surfaces
active participation
tel (0.03 *,
G / G) 4th Trichlorethylene I. - A. 5 M. I. C. .61565 B. 6th ti Waxoline
Green G C. I. - A. 7th It II C. 26105 A. 8th ti Vaxoline
Red 0 C. I. 26105 A. 9 M. waxoline
Red 0 I. 21240 B. 10 M. Lithofor
Yellow A I. 21240 A. 11 H Lithofor
Yellow A I. - B. 12th M. III - A. M. III C. - B. 14th Il IV A. 15th 11 IV a 6 ίο 5 B. 16 1,1,1-Tr U; hioro-
ethane fc'axoline
Red 0 I. H

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- 10 -

~ 10 -

Table 1

(Continuation)

Belsp.
Mr. solvent *
dye
(0.2 & G / G) Color - * <■
surfaces
active participation
tel (0.05 %,
G / G) 17th 1,1,1-trichloro-
ethane Lithofor
Ymllmi A C.I.21240 B. 18th Methylene world: B. 19th Ii V'axollne
Purple A c, 1.60725 B. 20th IJ IV A. 21st 1,1,2-trichloro- ^]
1,2,2-trifluoroethane 'I. - B. 22nd t «M II c-; ■ 23 W It Wajcoline
Sect 0: c.ι.26105 C. 24 Perehloroethylene I. ■ *
B. 25th H : II C. 26th W. I ' ^: iii'''' • · - β ■ -.- τ;

The dye in the table with elij # r Pmuafr be ^ eiohii®fc # n were the following:

I '. «1,4-Bis (pn-butylakLlino): - 5, S-dihydroxy-anthrachinoia ^l

II «1,4-bis (isopropyliaralnQ) -a.nthraquinone '.

III «l- ^ Amlno-4-hydroiyanthrachlnon

IV "l-AmIno-2-methyl-anthraquinone"

The surfactants are the

A - Cetyl-pyrldlnlum-broraid (Pixanol C) B - Matrlum di (raethylarayl) suirosucainate (Ksnoxol MA) C - a lauryl derivative of a cyclic amine (imidrol LC).

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It wj.tüb a clear solution nn.t 'learn the following approach;

Trichlorethylene surface-active !? Medium { B) Viasser

Dye (see table 2)

The dyes rare the following

Parts by weight ^

97.8 ι ι

0.2

ϊ ? ba 1 1 s 2

Example Hr 27 28

Dye

Sapon Fast Orange G Methasol Feist- Red 3B Zapon Fast Yellcw C, G, G.

Color index

15 A

16260 & 45170 18820

Freshly anoed and poured aluminum was made in accordance with the example! it is removed and immersed for 10 minutes in an emulsion ctes obi-

the

gen approach, / 3yut the color stovi; not rinsed, rinsed.

The aluminum was immersed in boiling titanium oxide for ten minutes flushed.

In every attempt v / was there ?? anodized Aluminiurr _r colored in sineti gleiehniäßigen hue could not be gcJindert by Roiben with cold or hot VtasKer ^ with hot or cold acetone and with hot or cold Tz ⁱ ^ ichlo c.äthylen.

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BATH ORIGINAL

Claims (21)

Claim (IJ a process for coloring anodized aluminum, characterized in that freshly anodized aluminum is immersed in a dye bath containing a boiling solution or dispersion of a dye in a halogenated hydrocarbon solvent. 2. The method according to claim 1, characterized in that the dye bath a solution of the dye in the halogenated hydrocarbon solvent contains. ■ 3 · The method according to claim 1 or 2, characterized in that the dye bath contains a surface-active agent, ■ ' ■ · 4. The method according to claim ^ ₁ , characterized in that the dyebath contains an emulsion of an aqueous solution of the dye in the halogenated hydrocarbon solvent. 5 «Method according to one of claims 1 to 4, characterized in that the freshly anodized aluminum is dried prior to immersion in the dye bath ''' 6. The method according to claim 5 *, characterized in that 'the freshly anodized aluminum. by immersion in a desiccant which is a halogenated hydrochloric solvent contains »- 7. The method according to claim 6, characterized in that the erts / solvents in the drying treatment and; is used in the dye bath. - "·..> ■ 8. The method according to claims 6 or 7j, characterized in that; the drying bag! a solution of a surfactant » in the .halogenii / ^ jQit ^ öiö ^ nwasserst off contains solvents. BAD ORlQlNAL 9 · Method according to one of the preceding claims, characterized characterized in that following drying, the anodized aluminum is rinsed with a boiling hydrocarbon solvent will" " 10. The method of claim 9 * ₃ characterized in that the anodized aluminum is rinsed by immersion in the boiling halogenier "te hydrocarbon solvent. 11. The method according to claim 9 or 10, characterized in that that the halogenated hydrocarbon solvent used to rinse the anodized aluminum is the same solvent is how it is used in the dye bath, 12. The method according to any one of the preceding claims, characterized * that the amount of dye 0.01 to 5 * 0 wt .- #, based on the halogenated © hydrocarbon solvent. 12. The method according to claim 12, characterized in that the freshly anodized aluminum is dried before immersion in the dyebath and that the amount of dye is approximately 0.1 % by weight, based on the halogenated hydrocarbon solvent. 14. The method according to claim 12, characterized in that the freshly anodized aluminum is immersed in the dye bath while it is still wet, and that the amount of the dye is about 0.2 wt. ~%, Based on the halogenated hydrocarbon solvent. 15. The method according to any one of claims J5 to 14, characterized in that that the dyebath is a surfactant in one Amount up to 3% by weight, based on the halogenated hydrocarbon solvent, contains. - 14 BAO 081GINAL 109819/1782 16. The method according to any one of the preceding claims, characterized marked * that as halogenated hydrocarbon off iosi «i &; äisi '; ~ tel a chlorinated aliphatic agent vKahlenwasgorefcoff is used. 17. The method according to spoke .16 * 'thereby: gesfe ^ indicates ,. that as. halogenated hydrocarbonsitofilosuiigsinmittel Trlehloroäthyien ver " . is used ». '. ". 18. The method according to any one of claims 1 to 15 *, characterized in that that as a halogenated hydrocarbon solvent Cblorofluorofcohlene hydrogenation agent is used. ' 19 = method according to claim! \ 6 ää '& r 17 * - dadxiroh that as a superfi ^ oneftktjivee Mitts ©! betyl-p ^ rldiniura-bromide uses: · ■ '* ■ ■ 20 * The method according to claims 17 or 18, characterized in that: as a surface-active agent a sulfosucei has det \ 21. The method according to claims · 20 * thereby gekenhaeichöß-t ,. φ ^ 3 as SuIfosuccinat Matrium-di (iHeth | flaniy.l}; ™ sulfbsueaiiaat vei? »& 8g &&' will«