Ketene dimer paper sizing compositions

As an improved paper sizing composition, a ketene dimer dispersion consisting essentially of said dimer, an anionic dispersing agent selected from the group consisting of sodium lignin sulfonate, the condensation product of formaldehyde and sodium naphthalene sulfonate and mixtures thereof, a cationic resin which is the reaction product of epichlorohydrin with a polymer selected from the group consisting of (a) an aminopolyamide derived from a dicarboxylic acid and a polyalkylene polyamine having two primary amine groups and at least one secondary or tertiary amine group or (b) a condensate of cyanamide or dicyandiamide with a polyalkylene polyamine having the formula H.sub.2 N(C.sub.n H.sub.2n NH).sub.x H, wherein n is an integer 2 through 8 and x is an integer 2 or more, and water.