Process for the production of pigment preparations based on phythalocyanine pigments

Abstract

Phthalocyanine pigments and phthalocyanine pigment preparations in the .alpha. phase and in the .beta. phase are prepared with phase conservation in an environmentally safe and economical manner by a) first wet milling a phthalocyanine pigment in an inert liquid medium in a stirred ball mill which is operated at a power density of more than 2.5 kill per liter of milling space and a peripheral speed of the stirrer of more than 12 m/s with exposure to a grinding medium having a diameter of less than 1 mm under phase-conserving conditions, then b) subjecting the prepigment composition obtained by a) either b1) in the form of the mill base suspension thus obtained, or b2) after addition of an organic solvent to the mill base suspension obtained by a), or b3) in the case where the prepigment intermediate or the prepigment composition intermediate is isolated, after first taking it up in an organic solvent, to a finishing treatment at elevated temperature, and c) then isolating the resulting pigment or pigment preparation.

Dependencies are inferred from the claim text.