Granted Patent
Utility
US 5,189,095 · App. 07/808,099
High-impact polystyrene
Inventor:
Richard A. Hall
Patented Case
View Patent ↗
Granted: Feb 23, 1993
Filed: Dec 16, 1991
Inventor
Richard A. Hall
Assignee (at issue)
Amoco 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.