Granted Patent
Utility
US 4,290,987 · App. 06/054,050
Process for preparing microporous hollow fibers
Inventors:
John W. Soehngen, John Chu Chen
Patented Case
View Patent ↗
Granted: Sep 22, 1981
Filed: Jul 2, 1979
Inventors
John W. Soehngen
John Chu Chen
Assignee (at issue)
Celanese GmbH
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.