Patent ID: 8394867

Claim:
Polypropylene resin foamed beads comprising a polypropylene resin having a melting point of 115 to 135° C. and an Olsen flexural modulus of 500 MPa to 780 MPa, wherein a relationship between the Olsen flexural modulus of the polypropylene resin and the melting point of the resin satisfies the formula: (Olsen flexural modulus [MPa]+1400)/15 resin melting point (° C.) (Olsen flexural modulus [MPa]+1750)/20, and wherein an amount of ash on the surfaces of the foamed beads is 3,000 ppm by weight or less (including 0), the foamed beads show one or more endothermic peaks having a peak temperature in a temperature region not higher than the melting point of the resin and one or more endothermic peaks having a peak temperature in a temperature region exceeding the melting point of the resin and not lower than 130° C., in a first DSC curve obtained by heating 1 to 3 mg of polypropylene resin foamed beads when heated from room temperature to 200° C. at a rate of temperature rise of 10° C./min with a heat flux differential scanning calorimeter, and the total calorie of the endothermic peak is in the range of 2 to 12 J/g.