| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for producing a propylene-based resin microporous film that is excellent in the permeability of an lithium ion and mechanical strength, can constitute a high-performance lithium ion battery and can prevent a short circuit. <P>SOLUTION: The method for producing a propylene-based resin microporous film is characterized in that a propylene-based resin film A extruded from a T-die 2 is conveyed by a first cooling roll 3 having a surface temperature of 100 to 10°C lower than the melting point of the propylene-based resin and having a ratio (R<SB POS="POST">1</SB>/R<SB POS="POST">0</SB>) of the peripheral velocity (R<SB POS="POST">1</SB>) of the first cooling roll 3 to the extrusion velocity (R<SB POS="POST">0</SB>) of the propylene-based resin film of 5 to 80 and thereafter the propylene-based resin film A is further conveyed by a second cooling roll 5 having a surface temperature of 100 to 10°C lower than the melting point of the propylene-based resin and having a ratio (R<SB POS="POST">2</SB>/R<SB POS="POST">1</SB>) of the peripheral velocity (R<SB POS="POST">2</SB>) of the second cooling roll 5 to the peripheral velocity (R<SB POS="POST">1</SB>) of the first cooling roll 3 of 1.01 to 5.00. <P>COPYRIGHT: (C)2013,JPO&INPIT |
