| 摘要 |
PROBLEM TO BE SOLVED: To efficiently obtain the above copolymer narrow in both molecular weight distribution and composition distribution in high polymerization activity by conducting a reaction in the presence of a catalyst composed of a specific transition metal compound and aluminoxane. SOLUTION: This copolymer is obtained by copolymerization between (C) ethylene and (D) anα-olefin at -50 to 200 deg.C in the presence of a catalyst composed of (A) a cycloalkadienyl group-bearing compound of a transition metal selected from zirconium, hafnium and vanadium [e.g. bis(cyclopentadienyl) dimethylzirconium] and (B) aluminoxane. This copolymer has the following characteristics: content of the component C: 20-85wt.%; molecular weight distribution (Mw /Mn ):<=2.5; degree of crystallinity: <=30%; intrinsic viscosity [η]: 1.2-10dl/g; and B-number defined by formula I (PE is molar fraction of the component C; PP is molar fraction of the component D; PEP, is proportion of ethylene-α-olefin chain to the total dyad chain) satisfies formula II if the content of the component C is <=50mo1%, or formula III if >=50mol%.
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