Method for pigmenting semi-crystalline plastics with phthalocyanine pigments in a non-warping manner

A process for warpage-free pigmentation of a partly crystalline plastic comprising the step of pigmenting the partly crystalline plastic with a phthalocyanine pigment which was heated to not less than 80° C. as a suspension in an organic solvent in the presence of a carboxylic acid containing 2, 3 or 4 carboxyl groups or a salt of the carboxylic acid containing 2, 3 or 4 carboxyl groups, wherein the carboxylic acid is in the form of an alkali metal salt or an alkaline earth metal salt.

A process for preparing a phthalocyanine pigment, comprising the step of heating the phthalocyanine pigment to a temperature of not less than 80° C. as a suspension in an organic solvent in the presence of a carboxylic acid containing 2, 3 or 4 carboxyl groups or a salt of the carboxylic acid containing 2, 3 or 4 carboxyl groups, and wherein the organic solvent is selected from the group consisting of aliphatic acid amides, cyclic carboxamides, alcohols having 1 to 20 carbon atoms, glycols, ethers, glycol ethers, aromatic hydrocarbons, aromatic halohydrocarbons, nitrobenzene, sulfoxides, sulfones and mixtures thereof.