Effect of acrylic binder type and calcium carbonate filler amount on the properties of paint-like blends

The aim of this work has been to study the factors affecting the interaction between calcium carbonate (CaCO3) filler and acrylic binders in waterborne coatings. Therefore, the minimum amount of additives has been used in order to isolate the interaction between the filler and the binder, while the production of an applicable coating was assured. In this paper we report the preparation of CaCO3/poly(methyl methacrylate-co-butyl acrylate) P(MMA/BA) latex blends using only sodium polyacrylate as dispersing agent as additive. Paint-like blends were prepared with latexes of different nature in terms of particle size (120 nm-600 nm) and functional monomer (acrylic acid) and at different pigment volume concentration (PVC) values of 30, 40, 45 and 50. The effect of these variables has been investigated on the film properties (water uptake, gloss, mechanical properties and scrub resistance). Higher gloss values, more elastic mechanical properties and higher scrub resistances were observed for blends prepared with the latex of 120 nm particle size. The use of acrylic acid functional monomer led to slightly better properties. Therefore, this study overall demonstrated that better interaction is obtained when using the latexes with small particle size and with the acrylic acid functional monomer, leading to blends with CaCO3 weight loadings of 70% without the complete loosing of the cohesive properties.