Granted Patent
Utility
US 4,383,948 · App. 06/264,929
Hydrazone derivatives containing a quaternary ammonium group useful as UV absorbers
Inventors:
Beat Muller, Martin Roth
Patented Case
View Patent ↗
Granted: May 17, 1983
Filed: May 18, 1981
Inventors
Beat Muller
Martin Roth
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.