| 摘要 |
PROBLEM TO BE SOLVED: To obtain a novel propylene/ethylene block copolymer having improved crystallinity, consequent improved rigidity and surface hardness, high impact resistance and high hardness and also excellent in fatigue resistance, abrasion resistance, dimensional stability, chemical resistance, moldability, etc. SOLUTION: This copolymer satisfies the relationship: 100>=IPF>=95.0-6.788×log[η] (IPF is the isotactic pentad fraction, and [η]is the intrinsic viscosity) and satisfies the relationship: (tanδarea/weight fraction of cold-xylene solubles)>=0.6 (the tanδarea is the tanδarea of the propylene/ ethylene copolymer (at -30 deg.C or below).
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