Granted Patent
Utility
US 5,755,874 · App. 08/834,725
Process for preparing linear unsubstituted .beta.-phase quinacridone pigments
Inventors:
Manfred Urban, Dieter Schnaitmann
Patented Case
View Patent ↗
Granted: May 26, 1998
Filed: Apr 1, 1997
Inventors
Manfred Urban
Dieter Schnaitmann
Assignee (at issue)
Hoechst GmbH
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.