Granted Patent
Utility
US 4,245,057 · App. 06/020,961
Impact resistant polystyrene blends
Inventor:
Francis J. Slama
Patented Case
View Patent ↗
Granted: Jan 13, 1981
Filed: Mar 16, 1979
Inventor
Francis J. Slama
Assignee (at issue)
Standard Oil Company (Indiana)
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.