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:
Mar. 30, 2004
Filed:
May. 17, 2001
Mohan D. Karve, Memphis, TN (US);
Rosa M. Covarrubias, Bartlett, TN (US);
Gerald M. Dykstra, Bartlett, TN (US);
Saleem Mirza, Bartlett, TN (US);
Buckman Laboratories International, Inc., Memphis, TN (US);
Abstract
Methods of making paper or paperboard are described. According to one of the methods, an acidic aqueous alumina sol is introduced to a papermaking pulp to form a treated pulp having improved retention properties. The acidic aqueous alumina sol preferably has a pH of from about 3 to about 6. The sol preferably contains elongate secondary particles which are elongated from about 50 nm to about 300 nm in only one plane and formed by edge-to-edge coagulation of rectangular plate like primary particles having a length on one side of from about 10 nm to about 30 nm when observed through an electron microscope. The pulp may also be treated with at least one coagulant, at least one flocculant, at least one cationic starch, at least one cellulytic enzyme, at least one biocide, and/or other conventional papermaking pulp additives. The resulting pulp is formed into a sheet of pulp and then drained to form a paper or paperboard. Other papermaking processes are also described as is a papermaking apparatus for carrying out the methods. Paper and paperboard containing dried pulp that has been treated with an acidic aqueous alumina sol are also described. Methods to flocculate particulate materials in a dispersion are also described.