| 摘要 |
PROBLEM TO BE SOLVED: To provide a material having waterproof properties for effectively absorbing wideband noise of the frequency band ranging from a low frequency to a high frequency. SOLUTION: The waterproof sound absorbing material comprises a foam layer 1 disposed on the sound source side, a first porous material layer 2a laminated on the sound source side of the foam layer 1, and a second porous material layer 2b laminated on the rigid wall 3 side of the foam layer 1. The first and second porus material layers 2a and 2b are composed of the same substance, and formed of a water-repellent porous substance, specifically, glasswool with water-repellency (for example, floating wool formed by sticking water-resistant cloth on one surface of water-resistant glass wool), and the like. The foam layer 1 is formed of a foam consisting of respective components of first diol of 500 to 5,000 in molecular weight, second diol of≤500 in molecular weight, an inorganic filler, water as a foaming agent, and isocyanate as raw material components. COPYRIGHT: (C)2008,JPO&INPIT
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