Granted Patent
Utility
US 5,219,491 · App. 07/514,628
Stable aqueous formulations of pyrazoline fluorescent whitening agents
Inventor:
Eickhard Kuhl
Patented Case
View Patent ↗
Granted: Jun 15, 1993
Filed: Apr 25, 1990
Inventor
Eickhard Kuhl
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.