A robust method for the production of an emulsion polymer based on styrene-acrylic acid-acrylic ester was developed to give enhanced physical properties and/or reduced envhonmental impact. Replacing the methyl methacrylate content with n-butyl acrylate, tert-butyl acrylate and ethyl acrylate all gave stable polymer emulsions. Replacing methyl methacrylate with fatty acid based monomer containing no more than one polymerisable acrylate group per molecule also led to the production of a stable emulsion, with the fatty acid based monomer also acting as a self-emulsifying agent if having sufficient amphiphilic character. All stable emulsions were successfully used to produce composite materials.