Patent ID: 7569648

Claim:
A process for producing a polymer of ethylene containing from 1.0 to 30% by weight of at least one derived units of alpha-olefins, the process comprising contacting, under polymerization conditions, ethylene and at least one alpha-olefins in the presence of a 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, are hydrogen atoms, halogen atoms, or a R 10 , OR 10 , OR 11 O, OSO 2 CF 3 , OCOR 10 , SR 10 , NR 10 2 , PR 10 2 group, wherein R 10 is a linear or branched, saturated or unsaturated 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 heteroatoms belonging to groups 13-17 of the Periodic Table of the Elements; or two X can optionally form a substituted or unsubstituted butadienyl radical, wherein R 11 is a divalent radical selected from C 1 -C 20 alkylidene, C 6 -C 40 arylidene, C 7 -C 40 alkylarylidene and C 7 -C 40 arylalkylidene radicals; R 8 and R 9 , equal to or different from each other, are hydrogen atoms, halogen atoms, or linear or branched, saturated or unsaturated 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 heteroatoms belonging to groups 13-17 of the Periodic Table of the Elements; two adjacent R 8 and R 9 groups can optionally form a saturated or unsaturated 5 or 6 membered ring, said ring can bear alkyl substituents; R 1 , R 2 , and R 3 , equal to or different from each other, are C 1 -C 10 alkyl radicals; R 4 and R 5 form a condensed aromatic 6 membered ring; R 6 is a hydrogen atom; and R 7 is a hydrogen atom or a methyl radical; b) an alumoxane or a compound that forms an alkyl metallocene cation; and c) an organo aluminum compound, wherein the alpha-olefins are selected from 1-butene, 1-hexene, or 1-octene.