Patent ID: 8669329

Claim:
A thermoplastic elastomer composition comprising a propylene-based resin; and an ethylene-α-olefin copolymer rubber; wherein the composition has a crystallization time at 130° C. measured by differential scanning calorimeter (DSC) of from 250 to 1,000 sec, and wherein the propylene-based resin comprises component (A) and component (B), and the ethylene-α-olefin copolymer rubber comprises component (C), component (A): a propylene-based resin comprising 70% to 90% by weight of component (p) and 30% to 10% by weight of component (q) relative to 100% by weight of component (A) and having a melting temperature measured by differential scanning calorimeter of not less than 155° C., component (p): a propylene-based polymer having a propylene-based monomer unit content of from 90% to 100% by weight, component (q): an ethylene-α-olefin copolymer having an ethylene-based monomer unit content of from 20% to 80% by weight; component (B): a crystalline propylene-ethylene copolymer having a propylene-based monomer unit content of from 70% to 97% by weight, an ethylene-based monomer unit content of from 30% to 3% by weight, a melt flow rate measured at 230° C. and 21.18 N of from 1 to 100 g/10 min, and a melting temperature measured by differential scanning calorimeter of from 80° C. to 130° C.; component (C): an ethylene-α-olefin copolymer rubber having an ethylene-based monomer unit content of from 35% to 75% by weight, an α-olefin-based monomer unit content of from 65% to 25% by weight, and a Mooney viscosity ML 1+4 , 125° C. of from 30 to 100, wherein the composition comprises 100 parts by weight of component (A), 10 to 100 parts by weight of component (B), and 50 to 200 parts by weight of component (C), wherein component (A) is a propylene-based resin that does not have a threo-form —CHCH 3 —CHCH 3 — structure, and component (B) is a crystalline propylene-ethylene copolymer that has a threo-form —CHCH 3 —CHCH 3 — structure, and wherein component (A) has the ratio of [ηcxs] to [ηcxis] ([ηcxs]/[ηcxis]) of from 1.8 to 8; [ηcxs]: the intrinsic viscosity measured at 135° C., in tetralin of a xylene-soluble fraction at 20° C., [ηcxis]: the intrinsic viscosity measured at 135° C., in tetralin of a xylene-insoluble fraction at 20° C., and wherein component (A) has a propylene unit content of from 94.8% to 98% by weight.