Patent ID: 8608908

Claim:
A method for inhibiting deposits of multivalent C 16 or higher fatty acid salts on paper surface sizing equipment when treating at least one surface of a paper substrate with a cooked paper surface sizing solution and a solution of multivalent cations, comprising the following steps of: (a) to a cooked paper surface sizing composition comprising above about 10% cooked surface sizing starch solids and no more than about 300 ppm C 16 or higher saturated fatty acids, wherein the cooked surface sizing starch solids comprise from 0 to about 95% high fatty acid surface sizing starch and from about 5 to 100% low fatty acid surface sizing starch, adding a monovalent hydroxide to thereby neutralize and convert the total fatty acids to monovalent fatty acid salts to thereby provide a cooked and neutralized paper surface sizing solution; (b) treating at least one surface of a paper substrate with the cooked and neutralized paper surface sizing solution to thereby, provide a surface sizing coating on the at least one surface; and (c) in the presence of the cooked and neutralized paper surface sizing solution of step (b), adding a solution of multivalent cations comprising a level of at least about 1000 ppm of the multivalent cations to thereby treat the at least one surface with the multivalent cations.