Suppressing gel in the continuous solution polymerization of a conjugated diene with a monovinyl aromatic compound

Claim 1

A continuous process for preparing a rubbery substantially random copolymer in continuous reactor means wherein monomers comprising at least one polymerizable conjugated diene and at least one copolymerizable monovinyl-substituted aromatic compound are polymerized under solution polymerization conditions of diluent, temperature, and pressure, employing an organolithium initiator, and at least one randomizing agent in an amount sufficient to substantially randomize the copolymerization of said conjugated diene and said monovinyl-substituted aromatic compound, wherein said continuous reactor means comprises a first polymerization reactor means, optionally at least one second polymerization reactor means, and a terminating reactor means, and wherein said conjugated diene, said monovinylaromatic compound, said organolithium initiator, said randomizing agent, diluent, and at least one silicon polyhalide are added to said first polymerization reactor means, and the resulting polymerization reaction mixture moves substantially continuously through said continuous reactor means wherein the polymerization is substantially completed when the reaction mixture reaches said terminating reactor means, and said copolymer is withdrawn from said terminating reactor means, employing said silicon polyhalide in an amount effective to substantially suppress the formation of gel in said first polymerization reactor means and wherein said silicon polyhalide is a di-, tri-, or tetra-halide.