Patent ID: 6331229
Filing Date: 2001-12-18
Classification: D21H

Abstract:
A method of increasing retention and drainage in a papermaking furnish comprising adding to the furnish from about 0.02 lbs polymer/ton to about 20 lbs polymer/ton of a high molecular weight water-soluble dispersion polymer wherein the dispersion polymer has a bulk Brookfield viscosity of from about 10 to about 25,000 cps at 25.degree. C. and comprises from about 5 to about 50 weight percent of a water-soluble polymer prepared by polymerizing under free radical forming conditions at a pH of from above 5 to about 8 in an aqueous solution of a water-soluble salt in the presence of a stabilizer:i. 0 to about 30 mole percent of acrylic acid or methacrylic acid or the alkali metal, alkaline earth metal or ammonium salts thereof, and,ii. 100 to about 70 mole percent of acrylamide;wherein the stabilizer is an anionic water-soluble copolymer of acrylic acid or methacrylic acid and 2-acrylamido-2-methyl-1-propanesulfonic acid having an intrinsic viscosity in 1M NaNO.sub.3 of from about 0.1-10 dl/g and comprises from about 0.1 to about 5 weight percent based on the total weight of the dispersion, and the water-soluble salt is selected from the group consisting of ammonium, alkali metal and alkaline earth metal halides, sulfates, and phosphates and comprises from about 5 to about 40 weight percent based on the weight of the dispersion.