| abstract |
The present invention relates to an azo dye of formula I, II or III: (formula I, II or III); wherein R 1 and R 2 are each independently of the other one or more divalent groups selected from alkylene, arylene, aralkylene and cycloalkylene, which may be interrupted by —O—, —S—, —NH—, —NR 8 —, —COO—, —CONH— or —CONR 9 —, wherein R 8 and R 9 are alkyl or aryl, X is —O— or —NH—, R 3 is —CN or —CONH 2 , R 4 is methyl or trifluoromethyl and R 5 , R 6 , R 7 and R 8 are each independently of the others hydrogen, halogen or —CN, to a process for the preparation thereof and to the use thereof in a method of producing mass-coloured plastics or polymeric colour particles. |