Granted Patent
Utility
US 5,403,822 · App. 08/068,563
Esters of carboxylic acids of medium chain-length as a component of the oil phase in invert drilling muds
Inventors:
Heinz Mueller, Claus-Peter Herold, Stephan von Tapavicza, Michael Neuss, Wolfgang Zoellner, Frank Burbach
Patented Case
View Patent ↗
Granted: Apr 4, 1995
Filed: May 27, 1993
Inventors
Heinz Mueller
Claus-Peter Herold
Stephan von Tapavicza
Michael Neuss
Wolfgang Zoellner
Frank Burbach
Assignee (at issue)
Henkel Kommanditgesellschaft auf Aktien
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.