Granted Patent
Utility
US 4,374,232 · App. 06/263,222
Graft copolymer membrane and processes of manufacturing and using the same
Inventor:
William John Davis
Patented Case
View Patent ↗
Granted: Feb 15, 1983
Filed: May 13, 1981
Inventor
William John Davis
Assignee (at issue)
Gelman Sciences
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.