Catalysts for the polymerization of olefins

Claim 1

A catalyst for the polymerization of olefins comprising the product obtained by contacting the following components: (A) a cyclopentadienyl compound of the formula (I): (C₅R¹ x-m H 5-x) R² m (C₅R¹ y-m H 5-y ) n MQ 3-n (I) wherein M is a metal selected from the group consisting of Ti, Zr and Hf; C₅R¹ x-m H 5-x and C₅R¹ y-m H 5-y are equally or differently substituted cyclopentadienyl rings; the substituents R¹, same or different from each other, are alkyl, alkenyl, aryl, alkylaryl or arylalkyl radicals containing from 1 to 20 carbon atoms, which may also contain Si or Ge atoms, or groups Si(CH₃)₃, or two or four substituents R¹ of the same cyclopentadienyl group can form one or two rings having from 4 to 6 carbon atoms; R² is a bridging group which links the two cyclopentadienyl rings and is selected among CR³², C₂R³₄, SiR³₂, Si₂R³₄, GeR³², Ge₂R³⁴, R³₂SiCR³₂, NR¹ or PR¹, wherein the substituents R³, same or different from each other, are R¹ or hydrogen, or two or four substituents R³ can form one or two rings having from 3 to 6 carbon atoms; the substituents Q, same or different from each other, are hydrogen, halogen atoms, OH, SH, R¹, OR¹, SR¹, NR¹₂ or PR¹₂; m can be O or 1; n can be O or 1, being 1 when m=1; x is an integer comprised between m+1 and 5, preferably between (m+2) and 5; y is an integer comprised between m and 5; (B) an organometallic aluminium compound of the formula (II): AlR⁴ 3-z H z (II) wherein the substituents R⁴, same or different from each other, are alkyl, alkenyl or alkylaryl radicals containing from 1 to 10 carbon atoms, which may also contain Si or Ge atoms, at least one of the substituents R⁴ being different from a straight alkyl group; z can be O or 1; and (C) water; the molar ratio between the organometallic aluminium compound and water being comprised between 1:1 and 100:1, with the proviso that at least part of the aluminium is present in a form different from an alumoxane compound of formula (III): wherein the substituents R⁴, same or different from each other, are as defined above.