Patent ID: 7569647

Claim:
A process for producing a polymer of ethylene containing from 5% to 40% by mol of derived units of at least one alpha-olefin of formula CH 2 ═CHA, wherein A is a C 2 -C 20 alkyl radical and optionally up to 5% by mol polyene, comprising contacting, under polymerization conditions, ethylene, said at least one alpha-olefin and optionally said polyene, in the presence of a non-supported catalyst system obtained by contacting: a) a metallocene compound of formula (I): wherein M is zirconium, titanium or hafnium; X, equal to or different from each other, is a hydrogen atom, a halogen atom, a R, OR, OSO 2 CF 3 , OCOR, SR, NR 2 or PR 2 group, wherein the R substituents are linear or branched, C 1 -C 20 -alkyl, C 3 -C 20 -cycloalkyl, C 6 -C 20 -aryl, C 7 -C 20 -alkylaryl or C 7 -C 20 -arylalkyl radicals, optionally containing at least one heteroatom belonging to groups 13-17 of the Periodic Table of the Elements; and the R′ substituent is a C 1 -C 40 -alkylidene, C 6 -C 40 -arylidene, C 7 -C 40 -alkylarylidene or C 7 -C 40 -arylalkylidene; R 1 , equal to or different from each other, are a linear or branched C 1 -C 20 -alkyl radical; R 2 , equal to or different from each other, is a hydrogen atom or a linear or branched, C 1 -C 20 -alkyl radical; R 3 and R 4 , equal to or different from each other, are hydrogen atoms or linear or branched, C 1 -C 20 -alkyl, C 3 -C 20 -cycloalkyl, C 6 -C 20 -aryl, C 7 -C 20 -alkylaryl or C 7 -C 20 -arylalkyl radicals, optionally containing at least one heteroatom belonging to groups 13-17 of the Periodic Table of the Elements; or they can form together a condensed saturated or unsaturated 5 or 6 membered ring, optionally containing at least one heteroatom belonging to groups 13-16 of the Periodic Table of the Elements, said ring optionally bearing at least one substituent; R 5 and R 6 , equal to or different from each other, are hydrogen atoms or linear or branched, C 1 -C 20 -alkyl, C 3 -C 20 -cycloalkyl, C 6 -C 20 -aryl, C 7 -C 20 -alkylaryl or C 7 -C 20 -arylalkyl radicals, optionally containing at least one heteroatom belonging to groups 13-17 of the Periodic Table of the Elements; or they can form together a condensed saturated or unsaturated 5 or 6 membered ring, optionally containing at least one heteroatom belonging to groups 13-16 of the Periodic Table of the Elements, said ring optionally bearing at least one substituent; Q is a radical of formula (IIa) which is bonded to the indenyl at the position marked by the symbol *; wherein R 9 is a group of formula C(R 12 ) 3 wherein R 12 , same or different, is a linear or branched, C 1 -C 6 -alkyl radical, and the metallocene compound of formula (I) is in the racemic form; and b) an alumoxane.