Protective colloid-stabilized latex particles for modifying cement- or plastic-bonded systems, e.g. mortar or adhesives, comprise outer and inner phases of vinyl acetate polymer, with ethylene in at least one phase

摘要

Protective colloid-stabilized copolymer latex particles (CLP) with a heterogeneous morphology and an ethylene (E) content of less than 30 wt.%, comprising outer and inner phases each consisting of a polymer of vinyl acetate (VAC) with 0-40 wt.% (E) and possibly other monomers, in which at least one of the two phases contains (E). An Independent claim is also included for a process for the production of aqueous dispersions of CLP by: (1) emulsion polymerization of VAC in presence of protective colloids, initiators and optionally surfactants, and optionally in presence of E (in which case the ethylene pressure is less than 50 bar) and (2) continued polymerization with vinyl acetate by (a) addition of sufficient ethylene to increase the ethylene pressure to above about 60 bar or (b) addition of ionic monomer(s) and optionally ethylene.