Granted Patent
Utility
US 5,223,550 · App. 07/888,935
Fine polybenzimidazole-containing particles
Inventors:
O. Richard Hughes, Dieter Kurschus
Patented Case
View Patent ↗
Granted: Jun 29, 1993
Filed: May 26, 1992
Inventors
O. Richard Hughes
Dieter Kurschus
Assignee (at issue)
Hoechst Celanese Corporation
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.