Preparation of conjugated diene polymers modified with an organo-tin or germanium halide

Abstract

A process for producing a modified conjugated diene polymer which comprises the steps of (I) polymerizing a conjugated diene in an inert organic solvent in the presence of a catalyst comprising (a) a lanthanum series rare earth element compound, (b) an organoaluminum compound represented by the general formula, AlR.sup.1 R.sup.2 R.sup.3 (wherein R.sup.1, R.sup.2 and R.sup.3 which may be same or different, are hydrogen atoms or hydrocarbon groups of 1 to 8 carbon atoms and at least one of R.sup.1, R.sup.2 and R.sup.3 is said hydrocarbon group) and, if necessary, at least one member selected from the group consisting of (c) a Lewis acid and/or (d) a Lewis base, and then (II) modifying the resulting reactive polymer with a modifying compound of the general formula, R.sup.4.sub.n MX.sub.4-n (wherein R.sup.4 is an alkyl group of 1 to 20 carbon atoms or an aryl group, M is a tin atom, X is a halogen atom, and n is an integer of 1 to 3).

Dependencies are inferred from the claim text.