Hydrophilic cationic dispersion polymers for improved print quality and water fastness

A method of treating a substrate surface, comprising:

• applying an aqueous solution comprising a hydrophilic cationic dispersion polymer to a surface of a substrate with a size press, wherein the hydrophilic cationic dispersion polymer comprises repeating units derived from a first monomer and a second monomer, wherein:
• the first monomer comprises a nonionic monomer,
• the second monomer is at least one hydrophilic cationic monomer selected from the group consisting of:
• a diallyl-N,N-dimethylammonium halide and a third monomer of the formula I:
• wherein A1 is O or NH;
• B1 is a C2-C4 alkylene or hydroxypropylene;
• R1 is H or CH3;
• R2 and R4 are independently a C1-C2 alkyl;
• R3 is H or a C1-C2 alkyl;
• and X1 is an anionic counterion, and
• the hydrophilic cationic dispersion polymer contains a higher mole % of repeating units derived from hydrophilic cationic monomers than hydrophobic cationic monomers.

A paper composition, comprising:

• a paper substrate;
• a starch;
• a sizing agent;
• and
• 0.02 weight % to 0.7 weight % of a hydrophilic cationic dispersion polymer based on a dry weight of the paper substrate, wherein the hydrophilic cationic dispersion polymer comprises repeating units derived from a first monomer and a second monomer, wherein:
• the first monomer is acrylamide or methacrylamide,
• the second monomer is at least one hydrophilic cationic monomer selected from the group consisting of:
• a diallyl-N,N-dimethylammonium halide and a third monomer of the formula I:
• wherein A1 is O or NH;
• B1 is a C2-C4 alkylene or hydroxypropylene;
• R1 is H or CH3;
• R2 and R4 are independently a C1-C2 alkyl;
• R3 is H or a C1-C2 alkyl;
• and X1 is an anionic counterion selected from the group consisting of:
• a halide ion, a sulfate ion, a phosphate ion, a monohydrogen phosphate ion, and a nitrate ion, and
• the hydrophilic cationic dispersion polymer contains a higher mole % of repeating units derived from hydrophilic cationic monomers than hydrophobic cationic monomers.