Granted Patent
Utility
US 4,956,049 · App. 07/372,217
Process for sizing paper with anionic hydrophobic sizing agents and cationic retention aids
Inventors:
Michael Bernheim, Dieter Strasilla, Bernardo de Sousa, Peter Rohringer
Patented Case
View Patent ↗
Granted: Sep 11, 1990
Filed: Jun 23, 1989
Inventors
Michael Bernheim
Dieter Strasilla
Bernardo de Sousa
Peter Rohringer
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.