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:
May. 09, 2000
Filed:
Sep. 23, 1997
Applicant:
Inventors:
Jeffrey K-S. Wan, Kingston, CA;
M Catherine Depew, Kingston, CA;
Assignee:
Queen's University at Kingston, Kingston, CA;
Attorneys:
Primary Examiner:
Int. Cl.
CPC ...
D21C / ; D21C / ;
U.S. Cl.
CPC ...
162 72 ; 162 90 ;
Abstract
A method for reducing brightness reversion and yellowness (b*) of bleached mechanical wood pulps. The pulp is digested in an aqueous formaldehyde solution containing carbonate, preferably in an amount up to 30% by weight of pulp. Paper made from the digested pulp can be further improved by treating with a reversion inhibitor such as a polyethylene glycol bisthiol.