Patent ID: 6143833
Filing Date: 2000-11-07
Classification: C08F,C08L

Abstract:
A method for making a rubber-modified monovinyl aromatic polymer wherein the rubber is polybutadiene, the method comprising the steps of:introducing materials comprising butadiene, a preheated hydrocarbon solvent, and a polymerization catalyst into a continuous-stirred tank reactor;controlling the temperature and reaction conditions to initiate polymerization of the butadiene to polybutadiene within the mixture;polymerizing the butadiene until reaching a polybutadiene concentration of from about 9 to about 15 weight percent by weight of the mixture;diluting the mixture containing the polybutadiene by introducing a monovinyl aromatic monomer;heating the diluted mixture and flashing off the hydrocarbon solvent and unreacted butadiene monomer to produce a solution of polybutadiene in the monovinyl aromatic monomer;forming a polymerizable mixture comprising the solution of polybutadiene in the monovinyl aromatic monomer;controlling the temperature to polymerize the monovinyl aromatic monomer, thereby producing a monovinyl aromatic polymer containing grafted polybutadiene.