Patent ID: 7018430

Claim:
A method of mass-colouring synthetic materials, which comprises incorporating at least one pigment dye of formula wherein R and R 1 together form a heteroaryl radical of formula wherein X is —O—, —S—, —NR 6 — and R 6 is hydrogen, C 1 –C 12 alkyl, or phenyl that is unsubstituted or substituted by hydroxy, halogen, C 1 –C 4 alkyl and/or by C 1 –C 4 alkoxy and R 2 is hydrogen, or R 1 and R 2 together form a phenyl or heteroaryl radical of formula 2 and R is hydrogen, and the rings A and B may each independently of the other be substituted by C 1 –C 4 alkyl, C 1 –C 4 alkoxy, halogen, —COOR 3 , —CONHR 4 and/or by —SR 5 , wherein R 3 , R 4 and R 5 are each independently of the others hydrogen, C 1 –C 4 alkyl, C 6 –C 12 aryl or heteroaryl.