| abstract |
The present invention relates to an azo dye of formula I, II or III: (formul a I, II or III); wherein R1 and R2 are each independently of the other one or more divalent groups selected from alkylene, arylene, aralkylene and cycloalkylene, which may be interrupted by -0-, -S-, -NH-, -NR8-, -COO-, -CO NH- or -CONR9-, wherein R8 and R9 are alkyl or aryl, X is -O- or -NH-, R3 is -C N or -CONH2, R4 is methyl or trifluoromethyl and R5, R6, R7 and R8 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. |