| 摘要 |
Disclosed is a polypropylene composition excellent in balance of low temperature impact-strength, rigidity, heat resistance and transparency, which is featured by comprising 20-95% by weight of a polypropylene defined in the following [I] and 5-80% by weight of a propylene-alpha-olefin copolymer defined in the following [II]:[I] a polypropylene featured by having:(1) a ratio of isotactic pentad (mmmm) of 0.900-0.949,(2) the 2,1- and 1,3-propylene units in the polymer chain in the amount of 0-1 mole %,(3) a weight average molecular weight (Mw) of 40,000-1,000,000,(4) a ratio of a weight average molecular weight (Mw) to a number average molecular weight (Mn), i.e. (Mw)/(Mn) of 1.5-3.8, and(5) in case of elevating the temperature of o-dichlorobenzene continuously or stepwise up to given temperatures to measure the amount of eluted polypropylene at each temperature, the position of a main elution peak is 95-110° C. and the amount of components existing in the range of ±10° C. of the main elution peak is at least 90% of the total amounts of components eluted at a temperature higher than 0° C. and[II] a propylene-alpha-olefin copolymer containing 10-90% by weight of a constituent derived from propylene and 10-90% by weight of a constituent derived from alpha-olefin other than propylene.
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