Granted Patent
Utility
US 5,461,028 · App. 07/955,738
Fluid-drill-hole treatment agents based on carbonic acid diesters
Inventors:
Heinz Mueller, Claus-Peter Herold, Alfred Westfechtel, Stephan von Tapavicza
Patented Case
View Patent ↗
Granted: Oct 24, 1995
Filed: Dec 7, 1992
Inventors
Heinz Mueller
Claus-Peter Herold
Alfred Westfechtel
Stephan von Tapavicza
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.