To obtain a copolymer excellent in elastic recovery and transparency, and useful for a stretch film, a shrink film or the like by regulating the molecular weight distribution of a copolymer of an olefin, an alkenyl aromatic hydrocarbon and a diene within a specified range.
This copolymer is the one of (A) an olefin [e.g. ethylene and an α-olefin (e.g. propylene)], (B) an alkenyl aromatic hydrocarbon (e.g. styrene) and (C) a diene (e.g. divinylbenzene), having 1.5-12.0 ratio of the weight average molecular weight to the number average molecular weight. The copolymerizing composition is preferably 1-99 mol%; component B and 0.00001-9 mol% component C. The copolymer is obtained, for example, by carrying out the copolymerization in the presence of an addition polymerization catalyst obtained by contacting a transition metal complex with an aluminum compound and a boron compound.
IZEKI MASAKI
SUZUKI YASUAKI
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