Patent ID: 7078466
Filing Date: 2006-07-18
Classification: C08F

Abstract:
1. A process for the preparation of a polydiene which comprises the polymerization of a conjugated diene in the presence of a catalytic system which essentially consists in components (a) to (d), wherein: component (a): compound containing a rare-earth element having an atomic number from 57 to 71 in the Periodic Table, or a product obtained by reacting the above compound with a Lewis base; component (b): an organo aluminum derivative containing at least one halogen atom; component (c): an alumoxane; component (d): an organometallic compound of aluminum represented by general formula (I) AlR wherein R (i) essentially isothermal conditions at a temperature ranging from 70° C. to 140° C.; (ii) essentially adiabatic conditions with an initial temperature ranging from 50° C. to 90° C. and a final temperature ranging from 100° C. to 150° C.; the above process being continued under conditions (i) or (ii) until a polydiene is obtained, having branching index values (measured with the GPC-MALLS technique) lower than 0.90 and α parameter values (also measured with the GPC-MALLS technique) ranging from 0.53 to 0.30.