Granted Patent
Utility
US 6,042,620 · App. 09/257,713
p-diaminobenzene derivative compounds and dye compositions containing same
Inventors:
Hans-Juergen Braun, Laurent Chassot
Patented Case
View Patent ↗
Granted: Mar 28, 2000
Filed: Feb 25, 1999
Inventors
Hans-Juergen Braun
Laurent Chassot
Assignee (at issue)
Wella GmbH
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.