| 摘要 |
PROBLEM TO BE SOLVED: To provide an olefinic thermoplastic elastomer having high flowability, good flexibility and good balance between tensile fracture point elongation and low temperature impact resistance. SOLUTION: This olefinic thermoplastic elastomer comprises the below- described components A and B, and is obtained by dynamically thermally treating a composition in the presence of an organic peroxide. The composition is obtained by polymerizing the component A and then polymerizing the component B. The component A is propylene homopolymer or a propylene copolymer with the otherα-(2-8C) olefin, having an isotactic index of >=85% in an amount of 10-60 wt.% based on the total amount of the composition. The component B is a propylene-α-(2-8C) olefin copolymer containing propylene and ethylene as essential components, and satisfying the below-described conditions, in an amount of 40-90 wt.% based on the total amount of the composition. The xylene- insoluble fraction of the copolymer at room temperature: 5-10 wt.% based on the total amount of the composition. The xylene-soluble fraction of the copolymer at room temperature: 30-85 wt.% based on the total amount of the copolymer. The ethylene content in the xylene-soluble fraction at room temperature: 40-55 wt.%.
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