Abstract: The present invention relates to the method for the manufacture of graft copolymers by the polymerization of a monomeric mixture comprising at least one aromatic vinyl derivative monomer and at least one acrylic or methacrylic derivative monomer in the presence of a graftable monodimensional elastomer latex, comprising the steps of first carrying out the polymerization under aqueous emulsion polymerization conditions in the presence of an initial amount of a first monodimensional elastomer latex being the major portion of the latex entering into the composition of the graft copolymer until the xy/z ratio is greater than 30%; x being the total parts by weight of said monomers, y the conversion coefficient of said monomers expressed in percent of total amount, and z the total amount of elastomer expressed in parts by weight of dry solids, and thereafter adding the remaining amount of a second monodimensional elastomer latex and completing the polymerization reaction under suspension polymerization conditions.

Abstract: This invention relates to a method of preparing graft polymers by mass polymerizing a mixture of polymerizable vinyl monomers in the presence of an elastomer to which the vinyl monomers are to be grafted, the elastomer being soluble in at least one of the vinyl monomers and also insoluble in at least one of the vinyl monomers, which comprises:A. dissolving an elastomer in at least one monomer in which it is soluble;B. initiating a mass prepolymerization reaction;C.introducing the monomer or monomers in which the elastomer is insoluble during the prepolymerization reaction;D. completing the addition of the monomer or monomers prior to the phase inversion of the reaction medium; andE. completing the polymerization.