Patent ID: 7309747

Claim:
A process for producing a high-fluidity 1-butene-based polymer, comprising: homopolymerizing 1-butene, or copolymerizing 1-butene with ethylene and/or a C 3 to C 20 α-olefin except for 1-butene, in the presence of a polymerization catalyst comprising: (A) a transition metal compound having as a ligand, a double crosslinking type biscyclopentadienyl derivative represented by the following general formula (II): wherein M is a metal element belonging to Groups 3 to 10 or lanthanoid of the Period Table; X 1 is a ligand that forms a σ-bond with the proviso that when a plurality of X 1 groups are present, these X 1 groups may be the same or different from each other, and may be cross-linked with the other X 1 group or Y 1 ; Y 1 is a Lewis base with the proviso that when a plurality of Y 1 groups are present, these Y 1 groups may be the same or different from each other, and may be cross-linked with the other Y 1 group or X 1 ; R 4 and R 5 are independently a hydrogen atom, a halogen atom, a C 1 to C 20 hydrocarbon group, a C 1 to C 20 halogen-containing hydrocarbon group, a silicon-containing group or a hetero atom-containing group, and R 6 and R 7 as well as R 8 and R 9 are bonded to each other to form a ring; A 1 and A 2 are divalent cross-linking groups which may be the same or different from each other, and are independently a C 1 to C 20 halogen-containing hydrocarbon group, a silicon-containing group, a germanium-containing group, a tin-containing group, —O—, —CO—, —S—, —SO 2 —, —Se—, —NR 1 —, —PR 1 —, —P(O)R 1 —, —BR 1 — or —AlR 1 — wherein R 1 is a hydrogen atom, a halogen atom, or a C 1 to C 20 halogen-containing hydrocarbon group; q is an integer of 1 to 5 given by the formula: [(valence of M)−2]; and r is an integer of 0 to 3, and (B) at least one component selected from the group consisting of (B-1) a compound capable of forming an ionic complex by reacting with said transition metal compound (A), and (B-2) aluminoxane.