Granted Patent
Utility
US 5,209,849 · App. 07/874,480
Hydrophilic microporous polyolefin membrane
Inventors:
Hopin Hu, Zhihua Cai
Patented Case
View Patent ↗
Granted: May 11, 1993
Filed: Apr 24, 1992
Inventors
Hopin Hu
Zhihua Cai
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.