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. 21, 1997
Filed:
Jan. 19, 1995
M C Matthew, Morris Plains, NJ (US);
Sanjay Patnaik, Westwood, NJ (US);
Paul Hart, Surfside Beach, SC (US);
Thomas Amidon, Highland Mills, NY (US);
International Paper Company, Purchase, NY (US);
Abstract
A method for enhancing the deposition and retention of particulate filler on papermaking fibers. In a first vessel, there is formed a slurry of papermaking fibers and in a second vessel there is formed a slurry of lime or its equivalent. The fiber slurry is at a consistency of not greater than about 5%. These separately formed slurries are thereafter combined with a gaseous precipitant in a flow reactor and under conditions whereby the gaseous precipitant is subjected to rapid shear and calcium carbonate is deposited in situ on the fibers. Unexpectedly, the reaction time for the formation and deposition of the calcium carbonate filler is very rapid. Control over the pH of the reactants in the reactor is achieved through the sequence of introduction of the reactants to the reactor. Also, through selection of the molar ratio of the gaseous precipitant and lime, the morphology of the calcium carbonate crystals may be controlled.