Air bag housing cover

An air bag housing cover comprising:

• (A) 100 parts by weight of an olefin-based thermoplastic elastomer comprising (A1) a propylene homopolymer having an isotactic index of not less than 90%, and (A2) a copolymer of propylene and a C2 to C8 α-olefin other than propylene, said propylene homopolymer (A1) and said copolymer (A2) being present in amounts of 30 to 60% by weight and 70 to 40% by weight, respectively, based on a total amount of the components (A1) and (A2), and said copolymer having propylene unit and ethylene unit as essential constituting units,
• said olefin-based thermoplastic elastomer (A) being obtained by producing the component (A2) by polymerization subsequent to the production of the component (A1) by polymerization, and having a 0° C. eluate content of 30 to 60% by weight based on a total eluate content as measured at a temperature between 0° C. and 140° C. by a temperature rising elution fractionation using o-dichlorobenzene as a solvent;
• (B) 10 to 150 parts by weight of a propylene-based polymer;
• and
• (D) 15 to 180 parts by weight of an ethylene-α-olefin copolymer,
• the composition comprising said components (A), (B) and (D) having a bending modulus of 150 to 500 MPa.

An air bag housing cover comprising:

• (A) 100 parts by weight of an olefin-based thermoplastic elastomer comprising (A1) a propylene homopolymer having an isotactic index of not less than 90%, and (A2) a copolymer of propylene and a C2 to C8 α-olefin other than propylene, said propylene homopolymer (A1) and said copolymer (A2) being present in amounts of 30 to 60% by weight and 70 to 40% by weight, respectively, based on a total amount of the components (A1) and (A2), and said copolymer having propylene unit and ethylene unit as essential constituting units,
• said olefin-based thermoplastic elastomer (A) being obtained by producing the component (A2) by polymerization subsequent to the production of the component (A1) by polymerization, and having a 0° C. eluate content of 30 to 60% by weight based on a total eluate content as measured at a temperature between 0° C. and 140° C. by a temperature rising elution fractionation using o-dichlorobenzene as a solvent;
• (B) 10 to 150 parts by weight of a propylene-based polymer;
• and
• (D) 15 to 180 parts by weight of an ethylene-α-olefin copolymer,
• the composition comprising said components (A), (B) and (D) having a bending modulus of 150 to 500 Mpa,
• said air bag housing cover having at least one groove portion for destruction and having a morphology of island-like phase of a rubber component dispersed in a matrix of polypropylene;
• the circle-corresponding diameter of the rubber component phase being not more than 2 μm;
• and
• the average acicularity of rubber component phase represented by a ratio a/b wherein a and b represent a major axis diameter and minor axis diameter, respectively, being 2 to 10.