Catalysts for the polymerization of olefins

Claim 1

A catalyst for the polymerization of olefins comprising the product of the reaction between: A a zirconocenic compound of the formula (Cs R' n H 5-n )R" p (C 5 R' m H 5-m )ZrXq in which (C 5 R' n H 5-n ) and (C 5 R' m H 5-m ) are cyclopentadienyl groups, which may also be identical, and in which R is an alkyl, alkenyl, aryl, alkylaryl or arylalkyl radical containing from 1 to 20 C-atoms or else a CR 2 SiR 3 group or SiR 3 group with R defined similarly to R', or else, two or four R substituents of the same cyclopentadienyl group form rings having from 4 to 6C-atoms; R is a bivalent radical chosen from an optionally substituted alkenyl group containing from 1 to 8 C-atoms, a SiR 2 , PR or NR group with R defined similarly to R', said R forming a connecting bridge between two cyclopentadienyl groups; X stands for hydrogen, halogen, -OH, -OZr(C 5 R' n H 5-n )(C 5 R' m H 5-m ), -OR with R defined similarly to R', or a hydrocarbon radical having the meaning of R'; when q is equal to 2, the X substituents may also differ from each other; q is 1 if Zr is trivalent and it is 2 if Zr is tetravalent; p is 0 or 1 and n, m are integers from 0 to 5; (n + m) is ≧5 in the case where R is a hydrocarbon radical and p = 0; if p = 1, (n + m) is ≧3; when R is a -SiR 3 or -CR 2 SiR 3 group (n+m) is ≧1 if p = 0 or if p = 1 and R is an alkylenic group; (n+m) is ≧0 if p 1 and R" is SiR 2 , PR or NR. B ) a trialkyl-Al compound or an alkyl-Al monohydride of the formula: AIR 3-z H z in which R is an alkyl, alkenyl or alkylaryl radical with 1-10 C-atoms and z = 0 or 1.