Granted Patent
Utility
US 4,933,506 · App. 07/274,901
Process for the production of dihydric phenols
Inventors:
Takao Ogino, Shunji Arita, Masayuki Takeda, Masaru Kaya
Patented Case
View Patent ↗
Granted: Jun 12, 1990
Filed: Nov 22, 1988
Inventors
Takao Ogino
Shunji Arita
Masayuki Takeda
Masaru Kaya
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.