Granted Patent
Utility
US 4,634,530 · App. 06/395,648
Chemical modification of preformed polybenzimidazole semipermeable membrane
Inventors:
James E. Kuder, John Chu Chen
Patented Case
View Patent ↗
Granted: Jan 6, 1987
Filed: Jul 6, 1982
Inventors
James E. Kuder
John Chu Chen
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.