Granted Patent
Utility
US 4,927,973 · App. 07/285,254
Process for continuous purification of bisphenols
Inventors:
Walter Dong, Paul V. Shaw, James Laurel Buechele
Patented Case
View Patent ↗
Granted: May 22, 1990
Filed: Dec 16, 1988
Inventors
Walter Dong
Paul V. Shaw
James Laurel Buechele
Assignee (at issue)
SHELL OIL COMPANY
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.