Granted Patent
Utility
US 6,214,891 · App. 09/171,756
Process for producing a cation-exchanging polymer electrolyte membrane (PEM)
Inventors:
Arnold Schneller, Helmut Witteler
Patented Case
View Patent ↗
Granted: Apr 10, 2001
Filed: Dec 22, 1998
Inventors
Arnold Schneller
Helmut Witteler
Assignee (at issue)
Hoechst Research & Technology Deutschland GmbH & Co. KG
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.