Waterborne Casein-Based Latexes with High Solids Content and Their High-Throughput Coating Optimization

Over the past few years casein-based latexes have attracted increasing interest because of their good film forming properties. This paper investigates the use of acrylic/casein hybrid latexes with a solids content of 35% in a coating application, which involves the evaluation of nonformulated latexes as binders, the high-throughput formulation with different commercial agents (cosolvents, wetting agents, and defoamers) and the formulation optimization using statistic multivariable analysis. Latexes were obtained by emulsifier-free emulsion polymerization of acrylic monomers in the presence of a chemically modified casein containing 10 vinyl bonds per molecule. The optimized clear coats formulated from the hybrid latexes showed a good performance requiring a reduced formulation-agents concentration, which could be an important benefit from an environmental viewpoint. Together the above results demonstrate that the casein biobased latexes represent a promising alternative for the development of a new generation of ecological binders.