Granted Patent
Utility
US 4,907,609 · App. 07/236,477
Method of increasing the hardness of cigarette filter elements
Inventors:
Richmond R. Cohen, Jimmie D. McCarty
Patented Case
View Patent ↗
Granted: Mar 13, 1990
Filed: Aug 24, 1988
Inventors
Richmond R. Cohen
Jimmie D. McCarty
Assignee (at issue)
HERCULES LLC
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.