| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a PTFE porous film that can obtain the PTFE porous film in which air permeability and water pressure resistance are highly balanced. <P>SOLUTION: In the method of manufacturing the PTFE porous film in which an uncalcined sheet consisting of PTFE is drawn to a first direction, and then is drawn to a second direction, the treatment at the crystal melting point or higher of PTFE is not performed to the uncalcined sheet before drawing of the second direction, and the drawing of the second direction is performed at the crystal melting point or higher of PTFE. As a result, the PTFE porous film can be obtained whose quantity of airflow measured in accordance with JIS P 8117(1998) is 1.0 second/100 mL or less, and whose water resistance pressure measured in accordance with JIS L1092-B (high water pressure method) is 100 kPa or more. <P>COPYRIGHT: (C)2013,JPO&INPIT |
