Granted Patent
Utility
US 4,410,331 · App. 06/292,546
Condensation products containing sulphonic acid groups: additives for dyeing synthetic polyamide
Inventors:
Albert Wurmli, Hans-Ulrich Berendt
Patented Case
View Patent ↗
Granted: Oct 18, 1983
Filed: Aug 13, 1981
Inventors
Albert Wurmli
Hans-Ulrich Berendt
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.