Patent ID: 7459511

Claim:
A process for polymerizing 1-butene carrier out in liquid monomer, wherein the liquid monomer comprises liquid 1-butene, the process 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, or 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; with the proviso that when m is 1, A is not a carbon atom; m is 1 or 2; 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, or 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 or C 7 -C 40 arylalkylidene radicals; L, same or different, is a moiety of formula (IIa) wherein in the moiety of formula (IIa), T bonds to the cyclopentadienyl group in position 5; T is an oxygen (O) atom, a sulphur (S) atom, or a CH 2 group; R 3 is 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, or C 7 -C 20 -arylalkyl radicals, optionally containing heteroatoms belonging to groups 13-17 of the Periodic Table of the Elements; b) an alumoxane or a compound of formula D + E − , wherein D + is a Brønsted acid that donates a proton and to react irreversibly with a substituent X of the metallocene of formula (I) and E − is a compatible anion which stabilizes the active catalytic species originating from the reaction of the two compounds, and which is sufficiently labile to be removed by an olefinic monomer; and c) optionally an organo aluminum compound, wherein the process produces a polymer comprising more isotactic triads (mm) than syndiotactic triads (rr) and having an intrinsic viscosity higher than 1.0 dL/g.