Patent ID: 8030421

Claim:
A process for polymerizing 1-butene carried out in a liquid phase of monomer comprising the step of contacting, under polymerization conditions, 1-butene and optionally from 0 to 20% by mol of ethylene, propylene and/or an alpha olefins of formula CH 2 ═CHZ wherein Z is a C 3 -C 10 alkyl group, with a catalyst system obtained by contacting: a) a racemic or racemic-like bridged metallocene compound of formula (I) wherein R 1 , same or different, is hydrogen, 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, C 7 -C 20 -arylalkyl radical, optionally containing heteroatoms belonging to groups 13-17 of the Periodic Table of the Elements; A, same or different, is a carbon atom, a germanium atom or a silicon atom; m is 1 or 2, with the proviso that when m is 1, A is not a carbon atom; R 2 , same or different, is hydrogen, 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, C 7 -C 20 -arylalkyl radical, optionally containing heteroatoms belonging to groups 13-17 of the Periodic Table of the Elements; M is a transition metal atom selected from those belonging to group 4 of the Periodic Table of the Elements; X, same or different, is a hydrogen atom, a halogen atom, or a R, OR, OSO 2 CF 3 , OCOR, SR, NR 2 or PR 2 group, wherein R 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 radical, 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 or a OR 11 O group 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; L, same or different, is a moiety of formula (IIb) wherein R 3 and R 4 , same or different, are hydrogen, 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, C 7 -C 20 -arylalkyl radicals, optionally containing heteroatoms belonging to groups 13-17 of the Periodic Table of the Elements, or R 3 and R 4 can form a saturated or unsaturated condensed 5 or 6 membered ring optionally containing heteroatoms belonging to groups 13-16 of the Periodic Table of the Elements; b) an alumoxane; and c) optionally an organo aluminum compound.