Patent ID: 7744725

Claim:
A method of making paper comprising: mixing a pulp slurry and a polymer emulsion comprising a cationic starch having a nitrogen content (N %) of 0.2 to 0.8 percent (A) and polymer particles (B) having an average particle diameter of 0.2 to 19.4 μm and comprising at least vinyl monomer-derived structural units comprising 94.66 wt. % to 100 wt. % of vinyl acetate units, wherein the polymer particles (B) are obtained by an emulsion polymerization method, suspension polymerization method or dispersion polymerization method in the presence of said cationic starch having a nitrogen content (N %) of 0.2 to 0.8 percent (A) to form a mixture, such that the proportion of (A) is from 10 to 315 parts by weight relative to 100 parts by weight of the polymer particles (B); wherein the polymer emulsion has a solid content of 7.9 to 39% by weight and wherein the glass transition temperature (TG) of (B) is from 32° C. to 59° C.; filtering said mixture on a wire mesh to drain water out to form a paper layer, wherein said polymer emulsion is added to said pulp slurry at the time of papermaking, and wherein the emulsion polymerization method, suspension polymerization method or dispersion polymerization method is carried out in the presence of a surfactant.