Granted Patent
Utility
US 4,877,836 · App. 07/198,542
Viscosity index improver and composition containing same
Inventor:
Robert B. Rhodes
Patented Case
View Patent ↗
Granted: Oct 31, 1989
Filed: May 24, 1988
Inventor
Robert B. Rhodes
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.