Thermoplastic resin composition and injection-molded object thereof

摘要

A thermoplastic composition which is obtained by melt-kneading (1) 55 to 75 wt. % crystalline polypropylene resin together with (2) 10 to 30 wt. % elastomer comprising either a rubber containing a vinyl aromatic compound or a mixture thereof with an ethylene/alpha-olefin random copolymer rubber and (3) 15 to 25 wt. % talc having an average particle diameter of 3 mum or smaller. The composition satisfies specific requirements with respect to: the long period obtained by X-ray small-angle scattering attributable to the vinyl aromatic-containing rubber in a blend obtained by melt-kneading the ingredients (1) and (2); the shape and diameter of the elastomer particles present near the polypropylene/elastomer interface in the blend; and the difference between the glass transition point of the ingredient (1) and that of the composition attributable to the crystalline polypropylene homopolymer parts. The composition has a satisfactory balance between impact resistance and rigidity and has excellent injection moldability.