Patent ID: 8263701

Claim:
A polypropylene resin composition comprising from 50 to 94% by weight of a polypropylene resin (A), from 1 to 25% by weight of an ethylene-α-olefin copolymer rubber (B) comprising an ethylene-α-olefin copolymer rubber (B-1) comprising a C4 to C12 α-olefin and ethylene and having a density of from 0.85 to 0.91 g/cm 3 and a melt flow rate of from 0.9 to 20 g/10 min as measured at a temperature of 190° C. and a load of 2.16 kgf and/or an ethylene-α-olefin copolymer rubber (B-2) comprising a C5 to C12 α-olefin and ethylene and having a density of from 0.85 to 0.91 g/cm 3 and a melt flow rate of not less than 0.01 but less than 0.9 g/10 min as measured at a temperature of 190° C. and a load of 2.16 kgf, and from 5 to 25% by weight of an inorganic filler (C), where the amounts of (A), (B) and (C) are each based on the total weight of the polypropylene-based resin composition, wherein the polypropylene resin (A) is a crystalline propylene-ethylene block copolymer (A-1) satisfying the following requirements (1), (2), (3) and (4), or a polymer mixture (A-3) comprising the block copolymer (A-1) and a crystalline propylene homopolymer (A-2), requirement (1): the block copolymer (A-1) is a crystalline propylene-ethylene block copolymer comprising from 55 to 85% by weight, based on the total weight of the block copolymer (A-1), of a crystalline polypropylene portion and from 15 to 45% by weight, based on the total weight of the block copolymer (A-1), of a propylene-ethylene random copolymer portion, requirement (2): the crystalline polypropylene portion in the block copolymer (A-1) is a propylene homopolymer or a copolymer of propylene with 1 mol% or less, based on the total amount of all monomers in the copolymer, of ethylene or α-olefin having 4 or more carbon atoms, requirement (3): the weight ratio of propylene to ethylene contained in the propylene-ethylene random copolymer portion of the block copolymer (A-1) is from 75/25 to 40/60, requirement (4): the propylene-ethylene random copolymer portion of the block copolymer (A-1) comprises a propylene-ethylene random copolymer component (EP-A) and a propylene-ethylene random copolymer component (EP-B), the copolymer component (EP-A) having an intrinsic viscosity [ηl] EP-A of more than 6 dl/g but not more than 9 dl/g and an ethylene content [(C2′) EP-A ] of not less than 20% by weight but less than 50% by weight, and the copolymer component (EP-B) having an intrinsic viscosity [η] EP-B of not less than 0.5 dl/g but less than 3.5 dl/g and an ethylene content [(C2′) EP-B ] of from 30% by weight to 60% by weight.