| 摘要 |
PROBLEM TO BE SOLVED: To provide a polypropylene resin composition excellent in impact resistance without using a specific polypropylene composition system, a method for molding the resin composition and a bumper for automobiles. SOLUTION: This polypropylene resin composition is composed of a ternary polypropylene-based material and comprises an ethylene-propylene rubber having 1-3μm average particle diameter in the range from the outer surface to 10μm. The resin composition is obtained by compounding a crystalline PP resin having 60,000 to 90,000 average molecular weight with an EPM having 200,000 to 300,000 average molecular weight and inorganic filler in a composition ratio of (50-70%)/(10-30%)/(10-20%). This method for molding the PP resin composition comprises carrying out injection molding for a prescribed injection time and retention time at a prescribed temperature under a prescribed injection pressure and retention pressure. This bumper for automobiles is obtained by processing the PP resin composition in a prescribed shape and applying coating to the resultant processed product. |
