Cationic latex as a multifunctional papermaking wet-end additive

Cationic latex has the potential to be a unique wet-end additive. This addi tive could simultaneously improve the mechanical properties, sizing, and th e retention of fillers. Positively charged latex particles deposit uniforml y on negatively charged fibers suspended in water. After sheet formation an d drying, the particles coalesce into a polymeric film that protects the fi bers against water and acts to bind fibers. Latex particles also link fiber s and negative pigment particles, performing the role of a retention aid. L aboratory results obtained with experimental cationic latexes are compiled, and the factors that affect performance are reviewed.