Granted Patent
Utility
US 4,960,958 · App. 07/410,811
Catalysts for catalytic pyrolysis of phenol distillation residue and process for recovering useful substances by pyrolysis the same
Inventors:
Tetsuo Imamura, Tatsuo Shirahata, Kichiro Shoji
Patented Case
View Patent ↗
Granted: Oct 2, 1990
Filed: Sep 22, 1989
Inventors
Tetsuo Imamura
Tatsuo Shirahata
Kichiro Shoji
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.