Granted Patent
Utility
US 5,015,412 · App. 07/452,572
Alkaline tolerant sulfobetaine amphoteric surfactants
Inventor:
William J. Zeman
Patented Case
View Patent ↗
Granted: May 14, 1991
Filed: Dec 18, 1989
Inventor
William J. Zeman
Assignee (at issue)
Sherex Chemical Co., 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.