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:
Oct. 14, 2003
Filed:
May. 19, 2000
Applicant:
Inventors:
Jeffrey K. -S. Wan, Kingston, CA;
M. Catherine Depew, Kingston, CA;
Assignee:
Queen's University at Kingston, Kingston, CA;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
D21C 9/16 ;
U.S. Cl.
CPC ...
D21C 9/16 ;
Abstract
A method for bleaching unbleached softwood or hardwood pulps using hydrogen peroxide without added alkali for activation is described. The aqueous hydrogen peroxide solution contains an alkaline earth metal carbonate, preferably magnesium carbonate and can be used at elevated temperatures. Bleached hardwood or softwood mechanical pulps with high brightness, low yellowness (b*) and reduced reversion properties are produced.