Preparation of core-shell emulsion polymer and optimization of shell composition with respect to opacity of paint film

A series of core-shell latexes comprising a poly(n-butyl acrylate-co-methyl methacrylate-co-methacrylic acid) (PBA/MMA/MAA) core and a poly(styrene-co-acrylonitrile) (PS/AN), poly(butyl acrylate-co-methyl methacrylate) (PBA/MMA) shell were prepared at different shell composition ratios. These core-shell binders were used for preparation of decorative coatings. The latexes were synthesized by a semi-continuous sequential emulsion polymerization and characterized by using transmission electron microscopy (TEM), particle size analyser, viscometry and opacity of paint film. The core-shell emulsion with styrene/acrylonitrile ratio 60/40 as shell composition shows the best optical properties.