| abstract |
The invention is directed to a method or use of 2,9-dichloro-quinacridone as an alpha crystal phase inhibitor and optionally, 4,11-dichloroquinacridone during the beta-quinacridone or gamma-quinacridone crude pigment particle size reduction processes. The invention is also directed to solid solutions of quinacridone comprising about 98 to about 80 weight % gamma or beta-quinacridone, about 0.1 to about 10 weight % 2,9-dichloroquinacridone and about 0.1 to about 10 weight % 4,11-dichloroquinacridone. |