Granted Patent
Utility
US 4,423,252 · App. 06/279,692
Process for preparing bisphenols
Inventors:
Takao Maki, Tetsuo Masuyama, Toshiharu Yokoyama, Yoshiko Fujiyama
Patented Case
View Patent ↗
Granted: Dec 27, 1983
Filed: Jul 2, 1981
Inventors
Takao Maki
Tetsuo Masuyama
Toshiharu Yokoyama
Yoshiko Fujiyama
Assignee (at issue)
Mitsubishi Chemical 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.