Granted Patent
Utility
US 4,627,889 · App. 06/497,307
Process for sizing paper with anionic hydrophobic sizing agents and cationic retention aids
Inventors:
Michael Bernheim, Hubert Meindl, Peter Rohringer, Hans Wegmuller, Dieter Werthemann
Patented Case
View Patent ↗
Granted: Dec 9, 1986
Filed: May 23, 1983
Inventors
Michael Bernheim
Hubert Meindl
Peter Rohringer
Hans Wegmuller
Dieter Werthemann
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.