WATERPROOF VENTILATION FILTER, WATERPROOF VENTILATION MEMBER, AND HOUSING

• Main Author: SAWA EI
• Format: Patent
• Language: English
• Published: 09.10.2008
• Subjects: CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; LAYERED PRODUCTS; LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT ORNON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS; PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; PRINTED CIRCUITS; SEPARATION; TRANSPORTING

PROBLEM TO BE SOLVED: To provide a waterproof ventilation filter which is excellent in ventilation, resistance to water pressure and strength. SOLUTION: In the waterproof ventilation filter 4, a first polytetrafluoroethylene porous film 1 is laminated on one side of a base material 3 such as a nonwoven fabric, and a second polytetrafluoroethylene porous film 2 is laminated on the other side of the base material 3. In this case, the thickness and average pore size of the first polytetrafluoroethylene porous film 1 are larger than those of the second polytetrafluoroethylene porous film 2, respectively. Preferably, the thickness of the first polytetrafluoroethylene porous film 1 is at least 50 μm, and its average pore size is at least 1.0 μm, and the thickness of the second polytetrafluoroethylene porous film 2 is smaller than 50 μm, and its average pore size is smaller than 1.0 μm. COPYRIGHT: (C)2009,JPO&INPIT