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:
Apr. 09, 1996
Filed:
Mar. 31, 1994
James A De Witt, Burnaby, CA;
Donald T Eadie, North Vancouver, CA;
Gordon R Hayes, Powell River, CA;
Robert E Monahan, Powell River, CA;
MacMillan Bloedel Limited, Vancouver, CA;
Abstract
A pulp furnish containing predominantly wood-containing fibers (mechanical) and natural calcium carbonate as a filler is formed into a paper in a paper forming section of a paper machine at a neutral pH in the range of 6.7 to 7.5. Bentonite plus a suitable polymer such as a polyacrylamide produces a pulp stock that has exceptionally high drainage characteristics particularly when used with chalk as the filler. The pH of the stock in the headbox is maintained at the desired level of pH 6.7-7.3 by monitoring the pH in the headbox and adjusting the flow of pH reducing and buffering agent, preferably phosphoric acid, into the pulp prior to the headbox to obtain the desired pH in the stock.