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Abstract

Disclosed is a polypropylene composition comprising (A) polypropylene and (B) a specific propylene-1-butene random copolymer in a specific amount ratio. The propylene-1-butene random copolymer (B) is characterized in that: (1) the copolymer contains 50 to 95% by mol of constituent units from propylene and 50 to 5% by mol of constituent units from 1-butene, (2) the intrinsic viscosity, as measured in decahydronaphthalene at 135.degree. C., is in the range of 0.1 to 12 dl/g, (3) the molecular weight distribution (Mw/Mn), as determined measured by GPC, is not more than 3, and (4) the parameter B value indicating randomness of the copolymerized monomer sequence distribution is in the range of 1.0 to 1.5. Also disclosed is a polypropylene composite film comprising (I) a crystalline polypropylene layer and (II) a layer formed from the polypropylene composition, which is laminated on at least one surface of the crystalline polypropylene layer (I). The polypropylene composition is excellent in heat resistance and low-temperature heat-sealing properties as well as in flexibility and impact resistance. The polypropylene composite film is excellent in not only heat-sealing properties, particularly low-temperature heat-sealing properties, but also transparency, scratch resistance and blocking resistance.

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