| 摘要 |
PROBLEM TO BE SOLVED: To provide a sound insulating material for a vehicle which is fixed to an indoor side surface of a vehicle body panel, its weight is made light, sound absorbing performance is increased and in particular sound-shielding performance/sound absorbing performance in a low-frequency range is increased. SOLUTION: An insulator instrument panel 10 of an indoor surface of an instrument panel 20 is constructed by a laminated member of a hardlayer 11 with ultra-fine fibers being applied as a base and a porous spring layer 12 having sound-absorbing function. It is fixed to the instrument panel 20 through an air layer 13. In particular, it assures an effective sound-shielding/sound-absorbing performance also against noise in a low-frequency range by adjusting an aeration amount at the hard layer 11 to a value less than 5 cm<SP>3</SP>/(cm<SP>2</SP>sec). COPYRIGHT: (C)2005,JPO&NCIPI
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