Granted Patent
Utility
US 4,188,441 · App. 05/658,549
Flexible packaging films of high density polyethylene capable of forming easily openable heatseals
Inventor:
Stephen Cook
Patented Case
View Patent ↗
Granted: Feb 12, 1980
Filed: Feb 17, 1976
Inventor
Stephen Cook
Assignee (at issue)
Crown Zellerbach 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.