Patent ID: 6759465
Filing Date: 2004-07-06
Classification: C08L

Abstract:
A thermoplastic resin composition which is obtained by melt-kneading a mixture comprising (1) 55-75% by weight of a crystalline polypropylene-based resin, (2) 10-30% by weight of an elastomer comprising a vinyl aromatic compound-containing rubber and an ethylene-&agr;-olefin random copolymer rubber, the ethylene-&agr;-olefin random copolymer rubber comprising an ethylene-octene random copolymer rubber and (3) 15-25% by weight of talc having an average particle diameter of not more than 3 &mgr;m and which satisfies the following conditions (a)-(e):(a) when the crystalline polypropylene-based resin (1) has been melt-kneaded with the elastomer (2) comprising a vinyl aromatic compound-containing rubber and an ethylene-&agr;-olefin random copolymer rubber, the ethylene-&agr;-olefin random copolymer rubber comprising an ethylene-octene random copolymer rubber, the long period obtained by small angle X-ray scattering attributable to the vinyl aromatic compound-containing rubber is 12-24 nm, (b) when the crystalline polypropylene-based resin (1) has been melt-kneaded with the elastomer (2) comprising a vinyl aromatic compound-containing rubber and an ethylene-&agr;-olefin random copolymer rubber, the ethylene-&agr;-olefin random copolymer rubber comprising an ethylene-octene random copolymer rubber, elastomer particles which undergo micro phase separation to have the form of particle, and are present in the vicinity of the interface between particles of the elastomer and the crystalline polypropylene-based resin as matrix, have a particle diameter of not more than 30 nm, and (c) the difference (&Dgr;Tg=Tg1âˆ’Tg2) between the glass transition point (Tg1) assigned to the crystalline propylene homopolymer portion of the crystalline polypropylene-based resin (1) and the glass transition point (Tg2) assigned to the crystalline propylene homopolymer portion of a composition obtained by melt-kneading the crystalline polypropylene-based resin (1) with the elastomer (2) comprising a vinyl aromatic compound-containing rubber and an ethylene-&agr;-olefin random copolymer, the ethylene-&agr;-olefin random copolymer rubber comprising an ethylene=octane random rubber, and talc (3) is 4.0-7.0Â° C.