Patent ID: 7404854

Claim:
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, 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.