Abstract: A crosslinked resin composition obtained by crosslinking a composition comprising (A) 95-10 wt. % of a propylene polymer and (B) 5-90 wt. % of an ethylene/.alpha.-olefin copolymer having the following properties (I) to (iv) and prepared by copolymerizing ethylene with an .alpha.-olefin having 3 to 12 carbon atoms in the presence of a catalyst, said catalyst comprising a solid component and an organoaluminum compound, said solid component containing at least magnesium and titanium:______________________________________ (i) Melt index 0.01-100 g/10 min (ii) Density 0.860-0.910 g/cm.sup.3 (iii) Maximum peak temperature not lower than 100.degree. C. measured according to a differential scanning calorimetry (DSC) (iv) Insolubles in boiling not less than 10 wt.

Abstract: This invention provides a thermoplastic elastomer composition obtained by blending (A) a hard segment comprising a low-density ethylene-.alpha.-olefin copolymer formed by copolymerizing ethylene with an .alpha.-olefin by the use of a specific catalyst and characterized by specifically defined properties and (B) a soft segment comprising an ethylene-.alpha.-olefin copolymer rubber, or obtained by partial cross-linking of the resulting blend.This elastomer composition has characteristic features such as high flexibility, good fluidity, excellent tensile properties, good thermal resistance and oil resistance and low permanent strain.