Granted Patent
Utility
US 4,518,643 · App. 06/516,657
Plastic film
Inventor:
Michael A. Francis
Patented Case
View Patent ↗
Granted: May 21, 1985
Filed: Jul 25, 1983
Inventor
Michael A. Francis
Assignee (at issue)
Ethyl 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.