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:
Jun. 10, 2008
Filed:
Dec. 09, 2003
Yasuyuki Kamijo, Tokyo, JP;
Isao Onodera, Tokyo, JP;
Keigo Watanabe, Tokyo, JP;
Takanori Miyanishi, Tokyo, JP;
Yasuyuki Kamijo, Tokyo, JP;
Isao Onodera, Tokyo, JP;
Keigo Watanabe, Tokyo, JP;
Takanori Miyanishi, Tokyo, JP;
Nippon Paper Industries Co., Ltd., Tokyo, JP;
Abstract
Wood chips having low bleachability are impregnated with a chemical liquor at a pH range of 7-12 in aqueous solution and the chemical liquor from the impregnated chips is drained, whereby extractives contained in the chips and consuming bleaching agents can be removed to improve the effect of bleaching agents in a subsequent bleaching step. Bleached mechanical pulp is prepared by defibration by primary refining—bleaching—beating by secondary refining wherein pulp fibers are washed after defibrating wood chips having low bleachability and before bleaching the pulp fibers, whereby the amount of bleaching agents used can be reduced and bleached mechanical pulp having a Hunter brightness of 45-65% after secondary refining can be obtained.