Patent application number | Description | Published |
20090277141 | POROUS POLYTETRAFLUOROETHYLENE MEMBRANE AND METHOD OF PRODUCING THE SAME, AND FILTER MEDIUM - First, a mixture of a polytetrafluoroethylene fine powder and a liquid lubricant into a sheet-form body extending in a first direction. Next, the liquid lubricant is removed from the sheet-form body. Then, the sheet-form body is stretched by a factor of 40 to 250 in the longitudinal direction at a temperature equal to or higher than a melting point of polytetrafluoroethylene, and the stretched sheet-form body is further stretched by a factor of 3 to 40 in the width direction. Thus, a highly air-permeable porous polytetrafluoroethylene membrane is obtained. | 11-12-2009 |
20110143114 | WATER-PROOF SOUND-TRANSMITTING MEMBRANE, METHOD FOR PRODUCING THE WATER-PROOF SOUND-TRANSMITTING MEMBRANE, AND ELECTRICAL APPLIANCE INCLUDING THE WATER-PROOF SOUND-TRANSMITTING MEMBRANE - The present invention provides a water-proof sound-transmitting membrane including a polytetrafluoroethylene (PTFE) porous membrane, in which the waterproofness is enhanced further with little lowering of the sound transmittance. The water-proof sound-transmitting membrane includes the PTFE porous membrane. The PTFE porous membrane includes a first porous layer, and a second porous layer stacked on and integrated with the first porous layer by a binding force acting between PTFE matrices. The first porous layer and the second porous layer each are composed of PTFE with a number-average molecular weight of 5.0×10 | 06-16-2011 |
20110255728 | SOUND-TRANSMITTING MEMBRANE FOR MICROPHONE, SOUND-TRANSMITTING MEMBRANE MEMBER FOR MICROPHONE PROVIDED WITH THE MEMBRANE, MICROPHONE, AND ELECTRONIC DEVICE PROVIDED WITH MICROPHONE - The present invention provides a sound-transmitting membrane for a microphone, to be disposed to a sound-collecting opening of the microphone so as to allow sound to transmit through the membrane while preventing a foreign matter from entering into the microphone through the opening. This membrane for a microphone prevents the entry of a foreign matter, such as fine dust and water vapor, that is difficult for conventional sound-transmitting membranes to block, and ensures the microphone performance. This membrane for a microphone is composed of a nonporous film or a multilayer membrane including a nonporous film, has a surface density of 30 g/m | 10-20-2011 |