Granted Patent
Utility
US 6,380,139 · App. 08/451,378
Bisdithiophosphoric acid derivatives as lubricant additives
Inventors:
Horst Zinke, Rolf Schumacher
Patented Case
View Patent ↗
Granted: Apr 30, 2002
Filed: May 26, 1995
Inventors
Horst Zinke
Rolf Schumacher
Assignee (at issue)
Ciba Specialty Chemicals Corporation
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.