The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 14, 1989
Filed:
Mar. 15, 1988
Applicant:
Inventors:
Norman Liebergott, Laval, CA;
Cyril Heitner, Pierrefonds, CA;
Assignee:
Pulp and Paper Research Institute of Canada, Pointe Claire, CA;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
D21C / ; D21C / ;
U.S. Cl.
CPC ...
162 70 ; 162 71 ; 162 72 ; 162 78 ; 162 80 ; 162 83 ; 162 84 ;
Abstract
A multistage process for bleaching high-yield and ultra high-yield pulps is described whereby the pulp is treated sequentially with a peroxygen compound, a reducing compound and a final peroxygen compound to achieve higher brightness levels.