Patent ID: 8044155

Claim:
A catalyst system obtained by a process comprising: contacting: (i) a support of a partially dealcoholated adduct of formula MgT 2 w R′OH, wherein T is chlorine, bromine, or iodine; R′ is a linear or branched C 1 -C 10 alkyl radical; and w is a non-integer number ranging from 3 to 0.1; with (ii) an organo-aluminium compound of formula H e A1U 3-e or H e A1 2 U 6-e , wherein U, same or different, are hydrogen, halogen, or hydrocarbon radicals comprising from 1 to 20 carbon atoms, and optionally comprise at least one silicon or germanium atom; with the proviso that at least one U is different from halogen; and e is a non-integer number ranging from 0 to 1; to obtain an adduct of formula (I) MgT 2 .y AlQ j (OR″) 3-j (I) wherein y ranges from 1.00 to 0.05; Q, same or different, are hydrocarbon radicals comprising from 1 to 20 carbon atoms, and optionally comprise at least one silicon or germanium atom; R″ is a linear or branched C 1 -C 10 alkyl radical; and j is a non-integer number ranging from 0.01 to 3.00; and contacting the adduct of formula (I) with at least one metallocene compound comprising titanium as a central metal and at least one ligand comprising a cyclopentadienyl skeleton; with the proviso that the metallocene compound has not been previously treated with an organo-aluminium compound of formula H e AlU 3-e or H e Al 2 U 6-e , or an alumoxane.