Granted Patent
Utility
US 4,920,205 · App. 07/329,647
Process for making azo pigments
Inventors:
Heinrich Rehberg, Hartmut Behringer
Patented Case
View Patent ↗
Granted: Apr 24, 1990
Filed: Mar 28, 1989
Inventors
Heinrich Rehberg
Hartmut Behringer
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.