Abstract: A catalyst system for the polymerization of olefins comprising the product obtained by contacting: (A) a metallocene complex; (B) an organometallic aluminium compound of formula (II): Al[CH2—C(Ar)R4R5]xHy??(II) wherein Ar is a substituted or unsubstituted aryl group having from 6 to 20 carbon atoms; R4 is a linear or branched, saturated or unsaturated, C1–C10 alkyl, C6–C20 aryl, C7–C20 arylalkyl or C7–C20 alkylaryl; R5 is hydrogen or a linear or branched, saturated or unsaturated, C1–C10 alkyl, C6–C20 aryl, C7–C20 arylalkyl or C7–C13 alkylaryl group; x=2 or 3; y=3-x; and water; the molar ratio (B)/(C) being between 1:1 and 100:1. These catalysts show an improved activity with respect to known catalysts, wherein different aluminium compounds are used.

Abstract: Catalysts for the polymerization of olefins are disclosed, which comprise the product obtained by contacting: (A) a bridged and/or substituted cyclopentadienyl compound of titanium, zirconium or hafnium; (B) an organometallic aluminium compound of the formula: Al(CH2—CR4R5—CR6R7R8)wR9qHz wherein R4 is a C1-C10 alkyl, alkenyl, or arylalkyl group; R5 is hydrogen or a C1-C10 alkyl, alkenyl, or arylalkyl group; R6 and R7 are C1-C10 alkyl, alkenyl, aryl, arylalkyl or alkylaryl groups; R8 is hydrogen or a C1-C10 alkyl, alkenyl, aryl, arylalkyl or alkylaryl group; R9 is a C1-C10 alkyl, alkenyl, or arylalkyl group, a carbon atom in the compound of formula (II) being optionally replaced by a Si or Ge atom; w is 1-3, z is 0 or 1, q=3−w−z, and (C) water; the molar ratio (B)/(C) being comprised between 1:1 and 100:1. These catalysts show an improved activity with respect to known catalysts, wherein different aluminium compounds are used.

Abstract: Catalysts for the polymerization of olefins are disclosed, comprising the product obtainable by contacting: (A) a bridged and/or substituted cyclopentadienyl compound of Ti, Zr or Hf; (B) one or more organometallic aluminium compounds of formula (II): AlR43−zHz wherein the substituents R4, same or different from each other, are linear or branched, saturated or unsaturated C1-C20 alkyl or alkylaryl radicals, optionally containing Si or Ge atoms, wherein at least one of the substituents R4 is different from a straight alkyl group; z is 0 or 1; and (C) water, the molar ratio between the organometallic aluminium compound and water being comprised between 1:1 and 100:1; said catalyst being obtainable by a process comprising the following steps: (i) contacting component (A) with part of component (B) in the absence of component (C); (ii) contacting part of component (B) with component (C) in the absence of component (A) and successively (iii) contacting the products obtained in steps (i) and (ii).

Abstract: Catalysts for the polymerization of olefins are disclosed, comprising the product obtainable by contacting: (A) a bridged and/or substituted cyclopentadienyl compound of Ti, Zr or Hf; (B) one or more organometallic aluminium compounds of formula (II): AlR 43−z Hz wherein the substituents R4, same or different from each other, are linear or branched, saturated or unsaturated C1-C20 alkyl or alkylaryl radicals, optionally containing Si or Ge atoms, wherein at least one of the substituents R4 is different from a straight alkyl group; z is 0 or 1; and (C) water; the molar ratio between the organometallic aluminium compound and water being comprised between 1:1 and 100:1; said catalyst being obtainable by a process comprising the following steps: (i) contacting component (A) with part of component (B) in the absence of component (C), (ii) contacting part of component (B) with component (C) in the absence of component (A) and successively (iii) contacting the products obtained in steps (i) and (ii).