Granted Patent
Utility
US 4,970,034 · App. 07/248,880
Process for preparing isotropic microporous polysulfone membranes
Inventors:
Ann L. Ly, Chaokang Chu, Thanh Duc Nguyen
Patented Case
View Patent ↗
Granted: Nov 13, 1990
Filed: Sep 23, 1988
Inventors
Ann L. Ly
Chaokang Chu
Thanh Duc Nguyen
Assignee (at issue)
W.R. Grace & Co. Conn.
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.