Granted Patent
Utility
US 5,112,892 · App. 07/578,294
Method for the production of an asymmetric semipermeable membrane from a solution of a sulfonated polyarylethersulfone
Inventors:
Peter T. Cardew, David R. Holmes, III, John W. Smith
Patented Case
View Patent ↗
Granted: May 12, 1992
Filed: Sep 6, 1990
Inventors
Peter T. Cardew
David R. Holmes, III
John W. Smith
Assignee (at issue)
IMPERIAL CHEMICAL INDUSTRIES LIMITED
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.