Granted Patent
Utility
US 5,041,664 · App. 07/556,686
Continuous process for preparing quaternary ammonium salts
Inventor:
Wei-Yang Su
Patented Case
View Patent ↗
Granted: Aug 20, 1991
Filed: Jul 23, 1990
Inventor
Wei-Yang Su
Assignee (at issue)
Texaco Chemical Inc.
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.