Granted Patent
Utility
US 4,889,655 · App. 07/280,107
Mixtures of fluorescent whitening agents
Inventors:
Heinz Hefti, Klaus Artz, Kurt Weber, Kurt Burdeska, Dieter Reinehr
Patented Case
View Patent ↗
Granted: Dec 26, 1989
Filed: Dec 5, 1988
Inventors
Heinz Hefti
Klaus Artz
Kurt Weber
Kurt Burdeska
Dieter Reinehr
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.