Granted Patent
Utility
US 4,606,943 · App. 06/674,486
Method for preparation of semipermeable composite membrane
Inventors:
Stanley F. Rak, Kenneth Ward
Patented Case
View Patent ↗
Granted: Aug 19, 1986
Filed: Nov 26, 1984
Inventors
Stanley F. Rak
Kenneth Ward
Assignee (at issue)
CULLIGAN INTERNATIONAL COMPANY
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.