| 摘要 |
PROBLEM TO BE SOLVED: To obtain a polypropylene block copolymer having a high impact resistance. SOLUTION: A polypropylene (PP)-ethylene-propylene copolymer rubber(EPR) block copolymer has the following characteristic values of (1)-(7): (1) interface thickness of the PP block and the EPR block: from 20 to 1,000 nm, (2) weight average molecular weight of the PP block: from 10,000 to 1,000,000, (3) mesopentad chain of the PP block: 95% or more, (4) dispersed particle size of the EPR block: from 0.2 to 3μm, (5) weight average molecular weight of the EPR block: from 50,000 to 1,000,000, (6) propylene content of the EPR block: from 20 to 80 mol.%, (7) molecular weight dependence of the EPR block composition: variance within±5%.
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