| abstract |
PURPOSE:To provide the titled flexible composition, outstanding in, esp. low- temperature impact resistance, optimum for bumpers, etc., comprising polypropylene resin, ethylene-alpha-olefin copolymer rubber and ethylene-alpha-olefin copolymer of low molecular weight in specified proportion. CONSTITUTION:The objective composition comprising (A) 50-90pts.wt. of polypropylene resin [pref., with a melt flow rate of 1.2-50g/10min (at 230 deg.C)], (B) 5-45pts.wt. of an ethylene-alpha-olefin copolymer rubber with a Mooney viscosity (ML1+4, at 100 deg.C) of 10-150 and (C) 5-45pts.wt. of an ethylene-alpha-olefin copolymer of low molecular weight with a weight-average molecular weight (Mw) of 5,000-50,000, ratio of weight-average molecular weight (Mw) to number- average molecular weight (Mn): (Mw/Mn) of 2-5 and alpha-olefin content of 30-75wt.% totaling 100pts.wt. For the component B, the alpha-olefin is pref. propylene and/or butene-1, the alpha-olefin content being pref. 15-80wt.%. |