Being mixed union with the production mannered null multiple minute

摘要

PROBLEM TO BE SOLVED: To provide an acoustic adjustable material that decreases the density and obtains a small sound speed.;SOLUTION: A plurality of very small particles and a surface active agent are mixed, the mixture is foamed by using the very small particles for a skeleton 2, and heated at a temperature of melting the very small particles and then solidified. The density of the acoustic material 1 is decreased by using air gaps 3 caused at foaming and sound propagation paths are elongated by wising a complicated shape obtained at foaming to slow down the sound speed.;COPYRIGHT: (C)2002,JPO