Granted Patent
Utility
US 6,806,235 · App. 09/856,082
Lubricants for drilling fluids
Inventors:
Heinz Mueller, Claus-Peter Herold, Frank Bongardt, Nadja Herzog, Stephan von Tapavicza
Patented Case
View Patent ↗
Granted: Oct 19, 2004
Filed: Aug 24, 2001
Inventors
Heinz Mueller
Claus-Peter Herold
Frank Bongardt
Nadja Herzog
Stephan von Tapavicza
Assignee (at issue)
Cognis Deutschland GmbH & Co. KG
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.