Patent ID: 6730744
Filing Date: 2004-05-04
Classification: C08F

Abstract:
A method of preparing block copolymers, comprising the steps of polymerizing a first monomer consisting of an alpha-olefin containing from 3 to 20 carbon atoms into a first, isotactic block, using a catalyst, then polymerizing at least one second monomer,said catalyst being in the form of a hydride complex of a trivalent metal from the rare earth group, having the formula I: â€ƒin which: Cp is a cyclopentadienyl radical; R1, identical or different at each occurrence, is a substituent of the cyclopentadienyl group and is an alkyl radical or a silicon-containing hydrocarbon radical, unsubstituted and containing from 1 to 6 carbon atoms; j, identical or different at each occurrence, is 1, 2 or 3; X is a divalent alkylene radical containing from 1 to 20 carbon atoms or Si(R)2 in which R is an alkyl radical having from 1 to 4 carbon atoms; y is 1 or 2; Ln is Y or Sm.