| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a microporous film that is thin and has uniform pore diameters, high tensile strength and transmissivity, and an excellent balance in physical properties.SOLUTION: The microporous film has the following characteristics. In a pore diameter distribution curve obtained by pressure changes in air flow volumes in a dry state and in a wet state, when a pore diameter indicating a maximum peak in the pore diameter distribution is represented by Dp (nm), a total value of pores having a pore diameter of 0.9Dp to 1.1Dp in the pore diameter distribution is 75% or more of the whole pores; and the maximum pore diameter is 45 nm or less. The film has tensile strength Sin the MD direction of 1000 to 3500 kgf/cmand a ratio S/Sof 1.1 to 2.5, which is a ratio of the tensile strength Sin the MD direction to tensile strength Sin the TD direction.</p> |
