Granted Patent
Utility
US 5,387,355 · App. 08/184,723
Use of anionic surfactant/dispersant blends for the deinking of groundwood newsprint
Inventor:
Mary Beth Letscher
Patented Case
View Patent ↗
Granted: Feb 7, 1995
Filed: Jan 21, 1994
Inventor
Mary Beth Letscher
Assignee (at issue)
Betz Laboratories, 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.