| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a composite film which is used suitably in an in-vehicle lithium secondary battery or a separator for an electrolytic capacitor, has high heat resistance and sufficient strength and integrity, includes a polyketone porous film having low moisture absorptivity, and has a satisfactory ion permeation velocity. <P>SOLUTION: The composite film is obtained by compositing a porous film with at least one nonwoven fabric. The porous film comprises a polyketone resin having ≥95 mol% of a repeating unit shown by a chemical formula (1). The composite film has a porosity of 30-80% which is shown by a numerical formula (2): the porosity (%)=[1-G/ρ/(t×A)]×100 (where G, ρ, t and A are as defined in the description of this patent), a degree of air permeation resistance of ≤800 seconds/100 ml, and a maximum pore diameter of 0.05-50 μm. <P>COPYRIGHT: (C)2012,JPO&INPIT |
