Azo pigments

摘要

The disazo pigments of the formula I <IMAGE> in which R1 denotes a benzolic, naphthalenic or a heterocyclic-aromatic bridging member, each R2, independently of the other, denotes hydrogen, halogen, methyl, ethyl, methoxy, ethoxy, trifluoromethyl or nitro, each R3, independently of the other, denotes hydrogen, halogen or C1-4-alkoxy-carbonyl, each R4 denotes oxygen or -NH-, each R5 and each R'5, independently of one another, denotes C1-5-alkyl, or the two R5s and/or the two R'5s together denote a group of the formula -(CH2)5-, each R6 and each R'6, independently of one another, has one of the meanings of R5, and each R7 denotes hydrogen, C1-8-alkyl or acyl, are outstandingly suitable as pigments for colouring plastics compositions, especially for polypropylene which is processed to give fibres.