Granted Patent
Utility
US 5,597,872 · App. 07/529,304
Hydrogenation of polymers having ketone groups
Inventor:
Carl L. Willis
Patented Case
View Patent ↗
Granted: Jan 28, 1997
Filed: May 29, 1990
Inventor
Carl L. Willis
Assignee (at issue)
SHELL OIL COMPANY
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.