PROPYLENE-ETHYLENE BLOCK COPOLYMER, RESIN COMPOSITION, AND BLOW-MOLDED ARTICLE

摘要

Provided are a propylene-ethylene block copolymer having MFR of from 0.01 to 1.0 g/10 min and comprised of (A) from 85 to 97 % by weight a 25.degree.C xylene-insoluble fraction and (B) from 3 to 15 % by weight of a 25.degree.C xylene-soluble fraction, wherein the fraction (A) is such that its stereospecificity index measured through 13C-NMR is at least 98. 0 %, its intrinsic viscosity [.pi.] falls between 2.5 and 5.5 dl/g, and its weight-average molecular weight, Mw, measured through GPC and the content, S, of the fraction having a molecular weight of at most 10 4.5 therein satisfy S (wt. %) ~ -5.3 x 10-6Mw + 7.58, and the fraction (B) is such that its ethylene unit content measured through 13C-NMR falls between 30 and 70 % by weight, and its intrinsic viscosity [.pi.] falls between 2.5 and 9.0 dl/g; and its blow-molded articles. The copolymer has good heat resistance, high rigidity, good impact resistance and good drawdown resistance, and its blow-molded articles have well-balanced rigidity and low-temperature barrier resistance.