Granted Patent
Utility
US 4,622,199 · App. 06/743,444
Process for extruding high molecular weight, high density linear ethylene polymers to form heavy tubular members
Inventor:
Michael Hirschberger
Patented Case
View Patent ↗
Granted: Nov 11, 1986
Filed: Jun 11, 1985
Inventor
Michael Hirschberger
Assignee (at issue)
Owens-Illinois Inc.
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.