| 摘要 |
PROBLEM TO BE SOLVED: To provide an acoustic material which is attached to the wall surfaces and ceilings of buildings around sound sources or the sound-insulating walls of expressways, etc., and decreases the air-born sounds, solid-born sounds and vibrations generated from outside like traffic vehicles, ships and various kinds of machinery in factories, etc. SOLUTION: This acoustic material 1 is formed by integrally molding and arranging thin-film layers 3 or 4 on the surfaces of an open cell foam 2. A viscoelastic body may be used for this open cell foam or the density of expansion may be inclinatorily varied in a thickness direction. Accordingly, this material has a higher effect of absorbing the sounds of a low frequency below about 500 Hz as compared with the prior art and particularly exhibits the excellent effect even at the low frequency below 100 Hz. Also, the material has a more excellent effect of decreasing the solid-born sounds and vibrations as compared with the prior art.
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