Granted Patent
Utility
US 5,223,091 · App. 07/796,951
Method of brightening mechanical pulp using silicate-free peroxide bleaching
Inventors:
Bernard H. Hetzler, Donald T. Eadie, James K. Turnbull
Patented Case
View Patent ↗
Granted: Jun 29, 1993
Filed: Nov 25, 1991
Inventors
Bernard H. Hetzler
Donald T. Eadie
James K. Turnbull
Assignee (at issue)
MacMillan Bloedel Limited
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.