Enhancement of paper dry strength by anionic and cationic polymer combination

A process for making paper to enhance the dry strength of the paper produced without substantially reducing its softness, comprising adding, separately or together, to the pulp stock in the wet end of a paper machine that consists essentially of a bleached pulp furnish, the following additives essentially consisting of (1) an anionic polymeric component selected from the group of polymers consisting of carboxymethyl guar, carboxymethyl bean gum, carboxymethyl hydroxyethyl guar, and a carboxymethyl hydroxypropyl guar, and (2) a cationic polymer selected from the group consisting of a cationic guar, a cationic acrylamide copolymer, a cationic bean gum, a cationic wet strength resin, and both a cationic wet strength resin and at least one of the other of said cationic polymers, the cationic wet strength resin being a polymeric amine-epichlorohydrin resin selected from the group consisting of a polyamide-epichlorohydrin (PAE) resin, a polyalkylenepolyamine-epichlorohydrin (PAPAE) resin, and an amine polymer-epichlorohydrin (APE) resin, in which amine polymer-epichlorohydrin resin amine groups have been alkylated with epichlorohydrin to produce a polyamine-epichlorohydrin resin that has azetidinium or epoxide functionality, the anionic component and the cationic component being added to the pulp furnish, in a total amount of 0.1 to 5 percent based on the dry weight of the pulp, and the ratio of the anionic component to the cationic component being from 1/20 to 10/1.