The present disclosure is directed to an ultra-high solids emulsion comprising a plurality of multiphase polymer particles, in which the multiphase particles comprises an acrylic-based copolymer derived from monomers comprising an alkyl methacrylate; an alkyl acrylate; a hydroxyalkyl acrylate; at least one or more acids; a vinyl aromatic compound; and a vinyl ester or vinyl lactam, a copolymerizable surfactant, at least one or more alkylphenol ethoxylate (APE) free nonionic surfactants, and at least one or more APE free anionic surfactants in aqueous medium in the presence of an initiator and a buffer. Additionally, methods for preparing such ultra-high solids emulsion and applications of such emulsion in coatings and adhesives are disclosed.