Granted Patent
Utility
US 5,338,407 · App. 07/812,534
Enhancement of paper dry strength by anionic and cationic guar combination
Inventor:
Sunil P. Dasgupta
Patented Case
View Patent ↗
Granted: Aug 16, 1994
Filed: Dec 23, 1991
Inventor
Sunil P. Dasgupta
Assignee (at issue)
HERCULES LLC
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.