Patent Number: 6,309,427

Title: Method of coloring aluminum oxide layers

Abstract: 1:2 chromium complex dyes of the formula ##STR1## in which R signifies C.sub.1-9 -alkyl or a radical of the formula ##STR2## R.sub.1 signifies C.sub.1-4 -alkyl, --COOM, --COOR.sub.5 or --CONH.sub.2, R.sub.2 signifies hydrogen or --SO.sub.3 M, R.sub.3 signifies hydrogen, methyl or methoxy, R.sub.4 signifies hydrogen, methyl, methoxy or chloro, n signifies from 0 to 3, M signifies hydrogen or a non-chromophoric cation and Kat.sup.+ signifies hydrogen or a non-chromophoric cation are suitable for dyeing artificially produced oxide layers on aluminium or aluminium alloys and so give highly lightfast dyeings in orange shades.

Inventors: Korte; Klaus (Ettingen, CH)

Assignee: Clariant Finance (BVI) Limited

International Classification: C09B 45/16 (20060101); C09B 45/00 (20060101); C25D 11/18 (20060101); C25D 11/24 (20060101); C25D 015/00 (); C25D 011/24 (); C09B 045/00 (); C09B 029/00 (); C09C 001/34 ()

Expiration Date: 10/30/2018