Granted Patent
Utility
US 4,904,815 · App. 07/107,920
Phenols and their production
Inventor:
Frederick H. Howell
Patented Case
View Patent ↗
Granted: Feb 27, 1990
Filed: Oct 13, 1987
Inventor
Frederick H. Howell
Assignee (at issue)
Ciba-Geigy
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.