Granted Patent
Utility
US 5,223,579 · App. 07/646,024
Solid viscosity index improvers which provide excellant low temperature viscosity
Inventors:
Robert B. Rhodes, Harvey E. Atwood
Patented Case
View Patent ↗
Granted: Jun 29, 1993
Filed: Jan 28, 1991
Inventors
Robert B. Rhodes
Harvey E. Atwood
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.