Granted Patent
Utility
US 4,463,167 · App. 06/477,093
Two stage high molecular weight polybenzimidazole production with phosphorus containing catalyst
Inventors:
Eui W. Choe, Anthony B. Conciatori, Bennett C. Ward
Patented Case
View Patent ↗
Granted: Jul 31, 1984
Filed: Mar 21, 1983
Inventors
Eui W. Choe
Anthony B. Conciatori
Bennett C. Ward
Assignee (at issue)
Celanese 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.