STRATEGIES TO SYNTHESIZE HIGH SOLIDS CONTENT/ LOW VISCOSITY LATEXES: APLICATIONS IN PAINTFORMULATIONS

摘要

A strategy to synthesize high solids content latexes with low viscosity by seeded semi-continuous emulsion polymerization has been developed. The proposed process is carried out in two steps. In the first step a seed polymer latex is loaded in the reactor and grown under monomer starved conditions until a given particle size. At a certain point during the feed a fraction of the seed latex is gently added to the reactor and the feed is continued until the desired particle size distribution and solids content is achieved. Following this technology it was possible to obtain latexes with solids content up to 70wt% and particle size bellow 350 nm. Thus, the performance of water-borne paints formulated with high solids content acrylic (BA/MMA) latexes with different particle size distributions was investigated. It was found that the water-borne paints formulated with the bimodal latex with particle sizes below 350 nm provided the best application properties in terms of drying time under ambient conditions, gloss and mechanical properties of the paints.