| 摘要 |
PURPOSE: A polypropylene block-copolymer resin is provided, which exhibits a higher melt tension with better moldability and is superior in the balance between the stiffness and the impact resistance and which is obtainable in an easier manner and can be molded by a high speed molding into a large-sized molded article exhibiting a better appearance with difficultly deformable nature. CONSTITUTION: A polypropylene block-copolymer resin comprises (A) 10-50% by weight of a higher molecular weight polypropylene having an intrinsic viscosity£η|, determined in decalin at 135°C of 6-13 dl/g, (B) 10-89% by weight of a lower molecular polypropylene having an intrinsic viscosity A eta U, determined in decalin at 135°C, of lower than 6 dl/g and (C) 1-40% by weight of an ethylene/ alpha -olefin copolymer having an intrinsic viscosity£η|, determined in decalin at 135°C, of 0.1-13 dl/g, wherein the block-copolymer resin has, when subjected to a dissolution fractionation with paraxylene, contents of constituent components of (X) 2-39% by weight of a component soluble in paraxylene at 23°C and (Y) 61-98% by weight of a component soluble in paraxylene at 135°C but insoluble in paraxylene at 23°C and exhibits the following characteristic features (1) and (2), namely, (1) a melt flow rate (MFR), determined at 230°C under a load of 2.16 kg, of 0.01-5 g/10 min. and (2) a molecular weight distribution expressed as Mw/Mn, determined by gel permeation chromatography (GPC), of 6-20 and an Mz/Mw value of at least 3.5.
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