Process for the manufacture of quinacridone pigments

Abstract

Abstract Prodn. of pigments (IA), mixed crystal pigments (IB) or pigment formulations (IC) based on linear, (un)substd. quinacridones comprises (a) wet milling the coarsely crystalline crude pigment to the required deg. of fineness in a liquid aq., aq. organic or organic medium in a ball mill with a power of over 2.5 kW/l, which has a stirrer operating at a peripheral velocity of over 12 ms and used milling balls with a dia. of at most 0.9 mm; (b) opt. subjecting the pre-pigment to solvent treatment at 50-200 deg.C; and then (c) isolating the pigment in the usual way.

Inventors

• 👤 Manfred Dipl.-Ing. Urban

Bibliographic Details