Granted Patent
Utility
US 5,721,201 · App. 08/746,824
Polymeric flow improver additives
Inventors:
Henricus P. M. Tomassen, Christinus Cornelis van de Kamp, Marinus Johannes Reynhout, Jian Lin
Patented Case
View Patent ↗
Granted: Feb 24, 1998
Filed: Nov 18, 1996
Inventors
Henricus P. M. Tomassen
Christinus Cornelis van de Kamp
Marinus Johannes Reynhout
Jian Lin
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.