Fremgangsmåde til fremstilling af kobberphthalocyaninpigmentpræparater i alfa-fasen

摘要

Copper phthalocyanine pigments and pigment preparations in the (alpha) phase are prepared with phase conversion from copper phthalocyanine crude pigments of the (beta) phase in an environmentally safe and economical manner by a) first wet milling a copper phthalocyanine pigment, which is predominantly present in the (beta) phase, in an aqueous, preferably neutral to alkaline medium in a stirred ball mill which is operated at a power density of more than 2.5 kW 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-converting 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.