Granted Patent
Utility
US 4,964,952 · App. 07/187,628
Method of controlling pitch using a cationically modified tannin
Inventors:
John J. Bennison, Richard P. Clifford
Patented Case
View Patent ↗
Granted: Oct 23, 1990
Filed: Apr 28, 1988
Inventors
John J. Bennison
Richard P. Clifford
Assignee (at issue)
W.R. Grace & Co. Conn.
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.