Granted Patent
Utility
US 5,558,809 · App. 08/540,507
Polymer electrets with improved charge stability
Inventors:
Werner Groh, Hans-Tobias Macholdt, Baylor D. Gibson, James Robert Walden, Clinton D. Felton
Patented Case
View Patent ↗
Granted: Sep 24, 1996
Filed: Oct 10, 1995
Inventors
Werner Groh
Hans-Tobias Macholdt
Baylor D. Gibson
James Robert Walden
Clinton D. Felton
Assignee (at issue)
Hoechst Celanese Corporation
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.