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. 23, 1990
Filed:
Dec. 21, 1988
Richard S Lamar, Littleton, CO (US);
William E Pratt, Englewood, CO (US);
Kenneth E Weber, North Hollywood, CA (US);
Robert E Roeder, Parker, CO (US);
Cyprus Mines Corporation, Englewood, CO (US);
Abstract
A method of and substances for reducing pitch in pulping and papermaking operations, particularly in furnishes made by mechanical pulping processes containing wood pulp in amounts greater than about 10% by weight, are disclosed. The method comprises adding to a pitch-containing furnish a stable, water dispersible particulate composite substance prepared by irreversibly adsorbing a water soluble cationic polymer, e.g., a poly(diallyldimethylammonium chloride), onto an essentially water insoluble particulate substrate, e.g., kaolin, thereby rendering the cationic polymer insoluble and immobile, the cationic polymer being sufficiently electropositive so that the particulate composite pitch control substance exhibits a zeta potential of at least about +30 mV, and preferably from about +60 mV to about +80 mV, the amount of the composite substance added to the furnish being effective to finely disperse pitch for removal as finely-dispersed pitch-containing aggregates in a paper sheet produced from said furnish. Further improvements in pitch control can be achieved using these particulate composite pitch control substances together with alum and/or relatively high molecular weight alkylene oxide polymers, and other desirable effects, including improved fines retention, better drainage and lower waste treatment costs are also obtained when practicing this method.