PROCESS FOR THE COLORATION OF ALUMINIUM

摘要

The present invention relates to a proces for producing colored oxide layers on aluminum or on aluminum alloys by dyeing in an aqueous dye bath, rinsing with water and sealing, wherein there is used for the dyeing at least one dye of the general formula wherein m is a value from 1 to 8, especially from 1 to 4, n is a value from 0 to 7, especially from 1 to 4, the sum of m and n being less than or equal to 8, A is the radical of a chromophore of the 1-aminoanthraquinone, anthraquinone, anthrapyrimidine, azo, azomethine, benzodifuranone, quinacridone, quinacridonequinone, quinophthalone, diketopyrrolopyrrole, dioxazine, flavanthrone, indanthrone, indigo, isoindoline, isoindolinone, isoviolanthrone, perinone, perylene, phthalocyanine, pyranthrone or thioindigo series, B is a hydrogen atom, a branched or straight-chain C_1-8alkyl, C_2-8alkenyl or C_2-8alkynyl radical, an aryl radical, an N-, O- or S-containing 5- or 6-membered heterocyclic ring, or a C_1-8alkyl-arylene, aryl-C_1-8alkylene or aryl-L-arylene radical, each of which may be substituted by one or more groups -OH, -Ocat, -COOH, -COOcat, -SH, -Scat, -OR¹, -SR², -C(O)OR³, -C(O)R⁴, -NR⁵R⁶, it being possible for the C_1-8alkyl radical to be uninterrupted or interrupted one or more times by -O- or by -S-, R¹, R², R³ and R⁴ are each independently of the others a C_1-8alkyl radical, C_7-11aralkyl radical or C_6-10aryl radical and R⁴ additionally may be a hydrogen atom, L is a bond, is -NR⁷ wherein R⁷ is a hydrogen atom or a C_1-4alkyl radical, or is a -N-N- group, and R⁵ and R⁶ are each independently of the other a hydrogen atom, a C_1-8-alkyl radical, a C_1-4alkoxy-C_1-4alkyl radical, a C_6-10aryl radical, a C_7-11aralkyl radical or a -(CH₂)_oOH radical wherein o is an integer from 2 to 6, X¹ is a hydrogen atom or cat and X² is a hydrogen atom or cat, cat being a cation, and to the colored substrates obtained according to such a process. Compared with commercially available dyes and dyes of formula I in which cat⁺ is an alkali metal, the dyeings obtainable according to the process of the invention have surprisingly high light-fastness properties.