Granted Patent
Utility
US 4,952,277 · App. 07/354,982
Process for producing kraft pulp for paper using nonionic surface active agents to improve pulp yield
Inventors:
Cheng-I Chen, Theresa D. Hancock
Patented Case
View Patent ↗
Granted: Aug 28, 1990
Filed: May 19, 1989
Inventors
Cheng-I Chen
Theresa D. Hancock
Assignee (at issue)
Bet PaperChem, Inc.
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.