Disazo pigments having improved heat resistance using lower alkyl and phenyl esters of acetoacetanilide

摘要

A disazo pigment is prepared by coupling the tetrazo compound of 3,3'-dichlorobenzidine with an acetoacetanilide compound which is other than those represented by the below-described general formula (I) and is free of water-soluble groups. In the present invention, about 0.5-50 mole % of the acetoacetanilide compound is replaced by a compound represented by the following general formula (I): <IMAGE> (I) wherein R means a methyl, ethyl, propyl or butyl group or a substituted or unsubstituted phenyl group.