Halftone gravure printing inks containing pyridone azo dyestuffs

Claim 1

A dyestuff which is obtained by reacting a pyridone azo dyestuffs of the formula ##STR52## in which D denotes the radical of a diazo component, T 1 denotes alkyl, aryl or --COOT 4 , T 2 denotes H, --CN, --COOT 4 or --CONH--T 5 (OH) n , T 4 denotes hydrogen or alkyl, if n is 0, T 3 and T 5 each independently represent C 1 -C 22 -alkyl, C 2 -C 22 -alkenyl, C 3 -C 7 -cycloalkyl, benzyl, phenethyl, C 2 -C 18 -alkoxyalkyl, phenoxy-C 1 -C 22 -alkyl or phenoxy-C 2 -C 18 -alkoxy? alkyl and if n is 1, 2, 3 or 4,T 3 and T 5 each independently represent a C 2 -C 18 -alkyl or C 2 -C 18 -alkyl which is interrupted by 1-6 oxygen atoms and m and n denote 0, 1, 2, 3 or 4, subject to the proviso that the sum of m+n is 1, 2, 3 or 4, with oxalic acid or a carboxylic acid of the formula [G']-(COOH).sub.a in which G' denotes an aliphatic or aromatic hydrocarbon radical having 1-51 carbon atoms and a denotes 2, 3 or 4 or a carboxylic acid of the formula [G"]-(OCH.sub.2 CH.sub.2 -COOH).sub.a ' in which G" denotes a saturated or unsaturated hydrocarbon radical having 2 to 20 carbon atoms or a saturated or unsaturated hydrocarbon radical in which the carbon chain can be interrupted by 1-9 non-adjacent oxygen atoms and a' denotes 2, 3, 4 or 5 to form an ester linkage between at least two identical or different pyridone azo dyestuffs.