Granted Patent
Utility
US 4,863,564 · App. 07/136,975
Method of bleaching high yield pulp by using dithionite ion and excluding oxygen
Inventors:
S. Allen Grimsley, James C. Robinson, Mark Schroeder
Patented Case
View Patent ↗
Granted: Sep 5, 1989
Filed: Dec 23, 1987
Inventors
S. Allen Grimsley
James C. Robinson
Mark Schroeder
Assignee (at issue)
Virginia Chemicals 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.