Patent ID: 7270727

Claim:
A method of producing sized paper in a paper making machine in which a paper pulp is entered into the wet end of the machine which comprises adding to the pulp, 1) an optical brightener, 2) sizing agent and 3) a water soluble amphoteric promoter resin that is (a) a polymerization reaction product of a monomer comprising at least one polymerizable cationic amine monomer of formula (I) where G is a selected from alkyl, alkenyl, allyl, aryl; heteroatom interrupted alkyl or alkenyl, wherein the heteroatoms are selected from the group N, S, and O; and J, K, and L are selected from hydrogen, alkyl akenyl, allyl, styrenyl, and aryl; heteroatom interrupted alkyl or alkenyl, wherein the heteroatoms are selected from the group N, S, and O; and X is a sizing compatible anion; and (b) at least one polymerizable organic acid of formula (II) where R x , R y , and R z , are hydrogen, alkyl, alkenyl, aryl heteroatom interrupted alkyl or alkenyl, wherein the heteroatoms are selected from the group N, S, and O; and E is an organic substituent selected from the group COO, SO3, HSO4, and H2PO4; and wherein the mole percent of the cationic amine units of formula I constitutes at least 25% of monomers in the amphoteric promoter resin and the mole percent of the organic acid of formula II constitutes at least 25% of monomers in the amphoteric promoter resin, wherein the additives 1), 2), and 3), become distributed throughout the interior of the resulting paper.