PURPOSE: To improve the acoustical absorptivity in a low frequency region without increasing the thickness of the material by incorporating flakes at a specified weight ratio into the foamed body of a high-polymer material.
CONSTITUTION: The acoustic material is formed by incorporating and dispersing 50 to 300pts.wt. flakes of mica or the like into 100pts.wt. high-polymer material in the production process of the foamed body of the high-polymer material, such as urethane. The flakes 3 having about the same grain sizes as the grain sizes of holes 4 are selected. The flakes 3 project into the holes 4 and constitute the intricately nested shapes when the foamed body 2 is formed and, therefore, the energy of propagating sound waves is easily absorbed and since the flakes are oscillated by the sound waves, the sound waves are converted to mechanical energy. The acoustical absorbing effect is eventually enhanced. The acoustical material having the sufficient acoustical absorptivity in the low-frequency region is obtd. in this way without increasing the thickness of the material.
| JP3209661 | RESONANCE-TYPE SOUND-ABSORBING PLATE |
| JP2018084054 | NON-INFLAMMABLE SOUND ABSORPTIVE MATERIAL |
UMEOKA KAZUAKI
KURIHARA YOSHITAKA
OKUZAWA MASAYUKI
MAEDA FUTOSHI
NAKAGAWA MASAHIRO
