A. Cationic Latexes Having Particles with Styrene-Butadiene Core and Cationic Groups Chemically Bound on Surface
U.S. Pat. No. 4,189,345 to Foster et al, issued Feb. 19, 1980, describes a fibrous product containing papermaking pulp, a structured-particle latex having pH independent cationic groups bound at or near the particle surface and a co-additive. The structured-particle latex has a copolymer core of styrene and butadiene, and an encapsulating layer of styrene, butadiene and vinylbenzyl chloride which is reacted with 2-(dimethyl amino) ethanol to form quaternary ammonium groups. The co-additive can be a hydrolyzed polyacrylamide having a degree of polymerization of 5500 and is used to enhance deposition of the cationic latex on the pulp fibers. In making the fibrous product, the structure-particle latex and an aqueous solution of the co-additive are added to an aqueous slurry of the pulp, which is then dewatered and dried by heating.
U.S. Pat. No. 3,926,890 to Huang et al, issued Dec. 16, 1975, discloses a process for preparing a "stable" cationic latex which is described as having "excellent adsorption" (only about 69% absorption of latex based on Example 5) onto substrates such as pulp, paper and the like. The Haung et al cationic latexes are prepared by emulsion polymerization of a haloalkyl ester of acrylic or methylcrylic acid with another monosaturated compound (e.g., butadiene) in the presence of a nonionic or preferably cationic surface active agent, and then reacting a basic nitrogen-containing compound with this copolymer to form the respective ammonium salt.