Granted Patent
Utility
US 6,325,891 · App. 08/553,324
Method of bleaching pulp without using chlorine chemicals in a (QP)Z bleaching sequence
Inventors:
Anders Bergqvist, Lars-Ove Larsson, Erik Nilsson, Petter Tibbling
Patented Case
View Patent ↗
Granted: Dec 4, 2001
Filed: Nov 20, 1995
Inventors
Anders Bergqvist
Lars-Ove Larsson
Erik Nilsson
Petter Tibbling
Assignee (at issue)
Kvaerner Pulping Technologies AB
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.