Preparation of a Styrene-acrylic Emulsion for Waterborne Paint and Its Film Properties

A waterborne styrene-acrylic dispersion emulsion with core-shell structure was prepared by semi-continuous solution and phase inversion emulsion polymerization using methacrylic acid (MAA) as hydrophilic monomer, hydroxypropyl methacrylate (HPMA) as crosslinking monomer, styrene (St), methyl methacrylate (MMA) and butyl acrylate (BA) as monomers. Subsequently, the styrene-acrylic emulsion film was further prepared. The effects of the MAA core-shell mass ratio, the amount of monomers such as MAA, St and HPMA on the properties of waterborne styrene-acrylic dispersion emulsion and film were discussed. The structure and thermal stability of the emulsion film were characterized by FTIR and TGA. The size and morphology of the styrene-acrylic emulsion particles were characterized by DLS and TEM. The results showed that when the mass ratio of MAA in the core shell was 2:8, the mass fraction of MAA was 7% (based on the mass of all monomers, the same below), the mass fraction of HPMA was 10%, and the mass ratio of St to MMA was 3:1, the prepared copolymer emulsion had excellent properties, with a particle size of 259.65 nm, viscosity of 349.1 mPa∙s, filming hardness of 72.4°, tensile strength of 1.422 MPa, and elongation at break 59.355%. The film water resistance time could approach 90 h, and the adhesion level was 1. © 2019, Editorial Office of FINE CHEMICALS. All right reserved.