Kenneth Charles Weber

US Patent:

49649558, Oct 23, 1990

Filed:

Dec 21, 1988

Appl. No.:

7/287866

Inventors:

Richard S. Lamar - Littleton CO
William E. Pratt - Englewood CO
Kenneth E. Weber - North Hollywood CA
Robert E. Roeder - Parker CO

Assignee:

Cyprus Mines Corporation - Englewood CO

International Classification:

D21H 1745
D21H 1754

US Classification:

1621646

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.