Granted Patent
Utility
US 4,311,567 · App. 06/207,595
Treatment of permionic membrane
Inventor:
Preston S. White
Patented Case
View Patent ↗
Granted: Jan 19, 1982
Filed: Nov 17, 1980
Inventor
Preston S. White
Assignee (at issue)
PPG Industries, Inc.
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.