GB1200414A - Production of graft polymers - Google Patents

Abstract

1,200,414. Graft polymers. MONSANTO CO. 12 Jan., 1968 [12 Jan., 1967], No. 1993/68. Heading C3G. A graft polymer is produced by a process comprising (1) polymerizing to at least 60% by weight conversion an aqueous emulsion containing at least one conjugated diene monomer, alone or together with not more than an equal weight of one or more monoethylenically unsaturated monomers, a water-soluble freeradical forming polymerization catalyst and such an amount of emulsifying agent as will produce and maintain particles having a number average diameter of substantially 0À06 to 0À20 micron in the disperse phase of the emulsion and (2) gradually introducing into the resulting diene polymer latex at least one polymerizable monoethylenically unsaturated aromatic hydrocarbon or halohydrocarbon monomer alone or together with at least one copolymerizable monomer, a molecular weight regulator and a water-soluble polymerization catalyst, the rate of introduction of the monomer or monomers into the latex being such as to ensure that the amount of unpolymerized monomer or monomers present therein does not exceed 10% of the weight of the diene polymer during the graft polymerization of the first 50% of the monomer or monomers being introduced and does not exceed 20% of the same weight during polymerization of the second 50% of the monomer or monomers being introduced, the amount of catalyst present in the polymerizing mixture during introduction of the first 50% of monomer or monomers being in excess of that required for polymerization of the monomer or monomers introduced, and the introduction of any emulsifying agent other than that used in the production of the diene polymer latex being deferred until at least 30% of the monomer or monomers has or have been added to the latex. In the examples, a butadiene-acrylonitrile copolymer latex is produced and grafted with styrene and acrylonitrile.