Method of increasing the dry strength of paper products using cationic dispersion polymers

A method for improving the dry strength of a paper product comprising

• a) adding to an aqueous cellulosic papermaking slurry an effective amount of one or more retention and drainage aids and an effective amount of a sole polymeric strength additive, wherein the polymeric strength additive is a cationic dispersion polymer prepared by polymerizing in an aqueous solution of a polyvalent anionic salt in the presence of a dispersant of:
• i. a cationic diallyl-N,N-disubstituted ammonium halide monomer of formula
• (H2C═CHCH2)2N+R1R2X−
• wherein R1 and R2 are independently C1-C20 alkyl, aryl or arylalkyl and X is an anionic counterion and
• ii. an acrylamide monomer of formula
• wherein
• R3 and R4 are independently hydrogen, C1-C10 alkyl, aryl or arylalkyl;
• R5 is hydrogen or methyl and
• R6 and R7 are independently hydrogen or C1-C10 alkyl,
• wherein the cationic dispersion polymer has a reduced specific viscosity of from about 0.5 to about 8 deciliters per gram, measured in 1.0 N ammonium nitrate solution, and a cationic charge of from about 25 mole percent to about 50 mole percent;
• b) draining the slurry to form a sheet;
• and
• c) drying the sheet.