Low residual monomer alpha -methylstyrene-acrylonitrile copolymers and ABS blends therefrom

摘要

A process for preparing a thermoplastic resin having high heat resistance by emulsion polymerization of an alpha -alkylstyrene compound of the formula: <IMAGE> wherein R1 is C1-C3 alkyl and R2 is hydrogen, C1-C3 alkyl or halo(C1-C3)alkyl and an unsaturated nitrile in a weight proportion of 65:35 to 80:20 in the presence of a radical initiator, characterized in that the whole amount of the alpha -alkylstyrene compound and 10 to 99% by weight of the unsaturated nitrile on the basis of its total amount are first subjected to polymerization and, after the polymerization, the remaining portion of the unsaturated nitrile is added to the reaction mixture and the resultant mixture is subjected to further polymerization until the polymerization is substantially completed.