Granted Patent
Utility
US 4,448,446 · App. 06/452,678
Process for the purification of triphenylmethane compounds and pressure sensitive copysheet containing same
Inventor:
Robert Flores
Patented Case
View Patent ↗
Granted: May 15, 1984
Filed: Dec 23, 1982
Inventor
Robert Flores
Assignee (at issue)
The Sherwin-Williams 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.