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, 2006
Filed:
Nov. 27, 2001
Applicants:
Xujun Hua, Kirkland, CA;
Makhlouf Laleg, Pointe Claire, CA;
Inventors:
Xujun Hua, Kirkland, CA;
Makhlouf Laleg, Pointe Claire, CA;
Assignee:
Pulp and Paper Research Institute of Canada, Pointe Claire, CA;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
D21C 3/04 (2006.01); D21C 3/06 (2006.01); D21C 3/12 (2006.01); D21H 13/48 (2006.01); D21H 11/06 (2006.01);
U.S. Cl.
CPC ...
Abstract
A method is disclosed for reducing or inhibiting alkaline darkening of mechanical pulp caused by the presence of calcium carbonate filler during production; the method comprises adding a sulfite, or sulfur-containing reducing agent, especially a sulfite to the mechanical pulp and the filler; the method is usefully applied in the production of mechanical pulp and paper in which calcium carbonate is used as a filler and also in the production of paper at neutral or mildly alkaline conditions.