| 摘要 |
PROBLEM TO BE SOLVED: To stably provide a polypropylene-based resin in-mold foam-molding body, which always has a high sound absorption coefficient of at least 0.7 over a wide frequency range. SOLUTION: By realizing the polypropylene-based resin in-mold foam-molding body having a rate of closed cell of≥50% and≤70%, a vertical incident sound absorption coefficient over all the frequencies≥4,000 Hz and≤6,000 Hz is at least 0.7 when the vertical incident sound absorption coefficcient at a thickness of 40 mm is measured based on ASTM E 1050. COPYRIGHT: (C)2007,JPO&INPIT |
