Heat-stable dyes of 2,6-diamino-pyridine series - for dyeing thermoplastics in the melt

摘要

Thermoplastics are coloured with dyes of formula (I): where A' is a gp. A or a gp. (II) D is the residue of a diazo component, R is H, alkyl or (methyl)phenyl, X is H, carbamoyl or CN, Z is a (cyclo) alkylene, aralkylene or arylene gp., where the alkylene gp. may be interrupted by O, S or N-substd. imino, and A is H, (substd.) (cyclo)alkyl, aralkyl, phenyl or acyl or may together form a 5-7 membered heterocyclic ring with N. (I) are used for dyeing thermoplastics in bulk at is not 300 degrees C, e.g polystyrene, hard PVC, polyethylene, polyamides, polyesters, polycarbonates, styrene-butadiene copolymers and ABS copolymers. (I) are stable to heat. They have up to 3.5 x the colour strength of dyes normally used for dyeing in bulk.