A study of the preparation and mechanism of the ambient temperature curing of acrylic latex with epoxy resins

A method for the ambient temperature curing of acrylic emulsions with epoxy resins has been developed. The results show that an acrylic resin can be effectively cured at room temperature through the addition of between 5 and 20 wt% of epoxy resin to the acrylic monomers. The resulting cured polymers have a degree of reticulation of the order of 75 %. It is shown that the tensile strength, and water and alkali resistance are greatly increased compared to those of uncured resins, while the elongation rate decreases sharply. The reticulation reaction was demonstrated to be a result of a reaction between epoxy and carboxyl groups, and was favoured when the amine concentration (curing agent) was low with respect to the concentration of epoxy groups, and when the amine was carboxylated by the acrylic monomers. It was also found that a grafting reaction took place between the acrylic monomers and the epoxy resins via an esterification of the carboxyl groups during the emulsion polymerization step. (C) 1997 Elsevier Science Ltd.