| 摘要 |
PROBLEM TO BE SOLVED: To provide a lightweight and inexpensive sound absorbing material capable of improving sound absorptivity at about 1 to 3 KHz without increasing the thickness. SOLUTION: The sound absorbing material comprises a base material 11 which has a plurality of recesses and projections formed by profile processing on a surface of a flat plate type porous elastic foamed body made of polyurethane foam etc., and a film 21 which is extended between peak parts 15a of the projections 15 and joined with the peak parts 15a of the projections 15. The film 21 is a plastic film of 10 to 1,000μm in thickness which is made of a polyurethane film etc., intervals of the projections 15 being preferably 5 to 200μmm and height differences between projections and recesses being 3 to 70 mm. COPYRIGHT: (C)2006,JPO&NCIPI
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