Process for the preparation of novel rubber-modified thermoplastic resin compositions using multiple feed streams

Abstract

A process for the preparation of rubber-modified thermoplastic compositions having high temperature stability includes the steps of dissolving a rubber polymer in a solvent selected from the group consisting of monovinyl aromatic monomers, olefinically unsaturated nitriles and mixtures thereof to form a feed solution, introducing the feed solution into a reactor capable of intimately mixing multiple immiscible phases, introducing into the reactor a separate liquid monomer feed stream containing monomers selected from the group consisting of unsaturated dicarboxylic acid anhydrides, olefinically unsaturated nitriles and mixtures thereof, heating the feed solution and feed stream under pressure to a temperature sufficient for polymerization to begin and intimately mixing and polymerizing the monomers around the rubber polymer in the reactor to form a thermoplastic resin composition. The rubber-modified thermoplastic resins produced by this process are novel and are characterized by having a high content of either olefinically unsaturated nitriles or unsaturated dicarboxylic acid anhydrides and high heat distortion temperatures. These thermoplastic resins generally comprise from about 45 to about 75 parts by weight of a monovinyl aromatic monomer, from about 10 to about 35 parts by weight of an olefinically unsaturated nitrile monomer and from about five to about 45 parts by weight of an unsaturated dicarboxylic acid anhydride monomer, providing 100 parts of a thermoplastic copolymer, and from about two to about 30 parts by weight of rubber polymer per 100 parts of the thermoplastic copolymer.

Dependencies are inferred from the claim text.