Granted Patent
Utility
US 4,478,956 · App. 06/520,214
Process for preparing bisphenols using pyridinealkanethiol derivatized sulphonated cation exchange resins
Inventors:
Takao Maki, Tetsuo Masuyama, Toshiharu Yokoyama, Yoshiko Fujiyama
Patented Case
View Patent ↗
Granted: Oct 23, 1984
Filed: Aug 4, 1983
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.