PIGMENTARY SYNTHESIS OF QUINACRIDONE SOLID SOLUTIONS

摘要

Pigmentary synthesis of quinacridone solid solutions A general method for the direct preparation of pigmentary quinacridone solid solutions is disclosed. The disclosed process comprises oxidizing a mixture of dihydroquinacridones directly to a pigmentary quinacridone solid solution wherein the oxidation is carried out by heating a reaction mixture comprising the dihydroquinacridone mixture, an alkali metal hydroxide, a water miscible organic solvent, water and effective amounts of an oxidizing agent and a particle growth inhibitor. In addition, an analogous process useful for the direct pigmentary synthesis of .alpha.-quinacridone is disclosed. The pigments prepared by the disclosed processes do not require additional particle-size reducing aftertreatments in order to be useful as pigments.