| abstract |
A foamed body produced by using expandable particles, and having communicating pores has sound absorption characteristics, and can be used as a sound absorptive material. However, a sound absorptive material comprising such a foamed body could not attain a high sound absorbing coefficient in a wide acoustic frequency band. The subject mold body is produced by using resin particles and has sound absorption characteristics, the resin particles having through pores and a porosity in a most densely packed state of 45-80 %. The void ratio of the molded body is 10-60 %, and the bulk density thereof 0.01-0.6 g/cm3. The molded body has not less than 3 continuous central frequency measuring points at which the sound absorbing coefficient is not less than 70 %, and not less than 7 continuous central frequency measuring points at which the sound absorbing coefficient is not less than 50 % in the sound absorbing coefficients at the central frequencies of 250, 315, 400, 500, 630, 800, 1000, 1250, 1600, 2000, 2500 and 3150 (Hz) which are determined by a sound absorbing coefficient measuring method according to the reverberation method under JIS A1409. |