| abstract |
A shock-absorbing material composed of an expansion-molded article of polypropylene resin particles is excellent in shock-absorbing property and impact resilience compared with shock-absorbing materials composed of other resin materials, but has not been said to be satisfactory in stiffness and energy absorption efficiency. The present invention relates to a shock-absorbing material composed of an expansion-molded article produced by using foamed particles comprising, as a base resin, a polypropylene homopolymer obtained by using a metallocene polymerization catalyst. The base resin has a tensile modulus of at least 15,000 kgf/cm2, and the expansion-molded article has a crystal structure that an inherent peak a and a high-temperature peak b appear as endothermic peaks on a DSC curve obtained by the differential scanning calorimetry of the molded article. The high-temperature peak b is a peak appeared on the temperature side higher than a temperature corresponding to the inherent peak a, and the quantity of heat at the high-temperature peak is at least 25 J/g. |