Granted Patent
Utility
US 4,440,954 · App. 06/251,461
Process for the purification of p-aminophenol
Inventors:
William Rex CLINGAN, Edward L. Derrenbacker, Thomas J. Dunn
Patented Case
View Patent ↗
Granted: Apr 3, 1984
Filed: Apr 20, 1981
Inventors
William Rex CLINGAN
Edward L. Derrenbacker
Thomas J. Dunn
Assignee (at issue)
MALLINCKRODT LLC
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.