Granted Patent
Utility
US 5,264,636 · App. 08/039,726
Process for producing highly pure phenol
Inventors:
Tatsuo Shirahata, Tetsuo Imamura
Patented Case
View Patent ↗
Granted: Nov 23, 1993
Filed: Mar 30, 1993
Inventors
Tatsuo Shirahata
Tetsuo Imamura
Assignee (at issue)
Mitsui Petrochemical Industries, Ltd.
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.