Granted Patent
Utility
US 4,496,472 · App. 06/450,718
Process for bleaching cellulosic fibre materials using oligomers of phosphonic acid esters as stabilizers in alkaline, peroxide-containing bleaching liquors
Inventors:
Paul Schafer, Hans-Ulrich Berendt
Patented Case
View Patent ↗
Granted: Jan 29, 1985
Filed: Dec 17, 1982
Inventors
Paul Schafer
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.