Patent ID: 7109284

Claim:
A low-molecular-weight ethylene polymer obtained by homopolymerizing ethylene or copolymerizing ethylene and an α-olefin of 3 to 10 carbon atoms in the presence of an olefin polymerization catalyst, wherein the ethylene polymer has: (1) a structural unit derived from ethylene in an amount of 81 to 100% by mol, and a structural unit derived from α-olefin in an amount of 0 to 19% by mol, (2) a weight average molecular weight (Mw), as measured in GPC, of less than 7000, (3) a molecular weight distribution (Mw/Mn) satisfying 1.1≦Mw/Mn≦2.2 and (4) a vinyl or vinylidene group at a terminal in the polymer main chain and a content of the groups, as determined by 1 H-NMR, of 90% or more based on all of the terminal, said catalyst comprising a transition metal compound represented by the following formula (I) wherein M is a Group 4 or 5 transition metal atom in the Periodic Table, m is an integer of 1 to 4, R 1 is a linear hydrocarbon group having 1 to 5 carbon atoms defined by the formula C n′ H 2n′+1 where n′=1–5 or hydrogen, R 2 to R 6 , which may be the same as or different from each other, each are hydrogen atom, a halogen atom, hydrocarbon group, heterocyclic compound residue, oxygen-containing group, nitrogen-containing group, boron-containing group, sulfur-containing group, phosphorus-containing group, silicon-containing group, germanium-containing group or tin-containing group, and two or more of them may be bonded to each other to form a ring, with the proviso that R 4 when halogen is chlorine, fluorine or iodine, and when m is 2 or more, two of groups R 2 to R 6 may be bonded to each other, n is a valence of M, X is hydrogen atom, a halogen atom, hydrocarbon group, oxygen-containing group, sulfur-containing group, nitrogen-containing group, boron-containing group, aluminum-containing group, phosphorus-containing group, halogen-containing group, hetero cyclic compound residue, silicon-containing group, germanium-containing group or tin-containing group, and when n is 2 or more, plural groups X may be the same as or different from each other and may be bonded to each other to form a ring.