Manufacture of rubber modified copolymers in an extruder type reactor

Abstract

A process for the impact modification of a plastic with a rubbery polymer to form a thermoplastic resin in a reactor extruder is provided. The process includes the steps of dissolving a rubbery polymer in at least one ethylenically unsaturated monomer to form a feed solution, introducing the feed solution into the feed section of a twin screw reactor extruder, heating the feed solution under pressure to a temperature sufficient for polymerization to begin, shearing the feed solution until the solids content formed is equal to at least about twice the rubber content in the feed solution so as to produce a phase inversion product wherein discrete particles of rubber become encapsulated in a continuous phase of plastic polymer formed from the ethylenically unsaturated monomer, thereafter reacting the phase inversion product until at least about 70 weight percent of the feed solution has been converted to a thermoplastic resin, and extruding the said thermoplastic resin through a die. A novel thermoplastic resin is also provided having a uniform distribution of rubber particles dispersed within the plastic phase of the resin, the rubber particles ranging in size of from about 0.01 to 0.50 microns. The process is particularly useful for the preparation of high nitrile and ABS type resins.