Granted Patent
Utility
US 4,490,562 · App. 06/462,258
Process for the preparation of a very pure commercial form of 4,2',4'-trichloro-2-hydroxydiphenyl ether
Inventors:
Werner Schreiber, Michael Marky
Patented Case
View Patent ↗
Granted: Dec 25, 1984
Filed: Jan 31, 1983
Inventors
Werner Schreiber
Michael Marky
Assignee (at issue)
Ciba-Geigy
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.