Granted Patent
Utility
US 5,169,992 · App. 07/870,973
Bisphenol A production using acidic clay catalysts
Inventor:
John F. Knifton
Patented Case
View Patent ↗
Granted: Dec 8, 1992
Filed: Apr 20, 1992
Inventor
John F. Knifton
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.