Granted Patent
Utility
US 4,439,478 · App. 06/368,598
Heat sealable, multi-ply polypropylene film
Inventors:
Daniel F. Ferguson, Frederick D. Stringer, Michael D. Esakov
Patented Case
View Patent ↗
Granted: Mar 27, 1984
Filed: Apr 15, 1982
Inventors
Daniel F. Ferguson
Frederick D. Stringer
Michael D. Esakov
Assignee (at issue)
W. R. Grace & Co., Cryovac Division
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.