Patent ID: 8273216

Claim:
A process for producing paper which comprises: (i) providing an aqueous suspension comprising cellulosic fibers, (ii) adding to the suspension after all points of high shear: a polymer P1 being a water-soluble cationic acrylamide-based polymer having an average molecular weight of at least about 1,000,000 prepared by polymerizing a composition comprising a monomer mixture comprising one or more cationic monomers represented by the general structural formula (II) wherein R 1 is H or CH 3 ; R 2 and R 3 are each H or a hydrocarbon group having from 1 to 2 carbon atoms; A is O; B is an alkyl or alkylene group having from 2 to 8 carbon atoms; R 4 is H or a hydrocarbon group having from 1 to 2 carbon atoms; and X − is an anionic counterion; a cationic starch having a degree of cationic substitution (DS C ) from 0.01 to 0.5, a charge density of from about 0.05 to about 6.0 meq/g and a weight average molecular weight of above about 1,000,000; and a polymer P2 being an anionic polymer selected from anionic silica-based polymers comprising anionic silica-based particles having an average particle size in the range of from about 1 to about 10 nm, and a specific surface area within the range of from 50 to 1000 m 2 /g; and (iii) dewatering the obtained suspension to form paper.