WATER-PROOF SOUND-TRANSMITTING MEMBRANE, METHOD FOR PRODUCTION OF WATER-PROOF SOUND-TRANSMITTING MEMBRANE, AND ELECTRICAL APPLIANCE USING THE MEMBRANE

摘要

PROBLEM TO BE SOLVED: To further improve waterproofness of a water-proof sound-transmitting membrane using a porous polytetrafluoroethylene film, without reducing sound transmissivity as further as possible. SOLUTION: A water-proof sound-transmitting membrane 10 comprises a porous polytetrafluoroethylene film 1 having a surface density of 1 to 20 g/m2. The porous polytetrafluoroethylene film 1 comprises: a first porous layer 1a; and a second porous layer 1b which is laminated on and integrated into the first porous layer 1a by means of the binding force acting between the polytetrafluoroethylene matrices. COPYRIGHT: (C)2009,JPO&INPIT