Patent ID: 8163133

Claim:
Aqueous dispersion useful for internal sizing or surface sizing in the production of paper, comprising at least one cellulose reactive sizing agent selected from the group consisting of ketene dimers and multimers, at least one cellulose non-reactive sizing agent selected from the group consisting of copolymers of styrene or substituted styrene with at least one other kind of ethylenically unsaturated monomers, at least one emulsifier selected from the group consisting of oxyalkylene phosphate esters and salts thereof, at least one cationic organic compound having a weight average molecular weight less than about 10000 and a condensated naphthalene sulfonate anionic stabilizer, wherein the cationic organic compound is a surfactant selected from the group consisting compounds having the general formula R 4 N + X − , where each R group, independently of each other, is hydrogen or a hydrocarbon group having from 1 to 30 carbon atoms, and X is an anion, and wherein the dispersion is predominantly anionic, and wherein said at least one emulsifier is present in an amount from 0.01 to 5 wt %, said surfactant is present in an amount from 0.1 to 0.55 wt % and said anionic stabilizer is present in an amount from 0.185 to 3 wt %, based on the dispersion, and wherein said anionic stabilizer is present in an amount greater than said surfactant, and wherein the oxyalkylene phosphate esters are of the formula: R 3 -A 1 -O-Q-R 4 where R 4 is —OH or —O-A 2 -R 5 ; A 1 and A 2 , independently of each other, are oxyalkylene chains with from 2 to 100 oxyalkylene units; Q is PO(OH); and, R 3 and R 5 , independently of each other, are hydrocarbon groups having from 3 to 50 carbon atoms.