Laked pyrazolone azo pigment, process for its preparation and its use

摘要

The invention relates to a yellow monoazo pigment which is obtained by diazotization of 2-amino-4-chloro-5-methylbenzene-1-sulfonic acid, coupling of the diazonium compound with 1-(3'-sulfophenyl)-3-methyl-5-pyrazolone and subsequent laking of the coupling product to the calcium salt. The new pigment has excellent heat stability and bleeding fastness and good light stability. It is particularly suitable for the pigmenting of polymeric plastics in the mass.