| abstract |
A process for obtaining 1-butene polymers optionally containing up to 30% by mol of ethylene, propylene or an alpha-olefin of formula CH 2 ═CHZ, wherein Z is a C 3 -C 10 alkyl group s, comprising the step of contacting under polymerization conditions 1-butene and optionally ethylene, propylene or said alpha-olefin, in the presence of a catalyst system obtainable by contacting: a) a metallocene compound of formula (I): R 3 R 2 R 4 0R˜RsMXpLLR 6 R 5 R′OR 2 R 4 (I) wherein: M is an atom of a transition metal belonging to group 3, 4, 5, 6 or to the lanthanide or actinide groups in the Periodic Table of the Elements; p is an integer from 0 to 3; X, is a hydrogen atom, a halogen atom, or a hydrocarbon group; R 1 is a hydrocarbon group; RZ, R 3 and R 6 are hydrogen atoms or hydrocarbon groups; R 4 and R 5 join to form a condensed saturated or unsaturaded 4-7 membered ring; and L is a divalent bridging group; and b) an alumoxane or a compound able to form an alkylmetallocene cation. |