| 摘要 |
PROBLEM TO BE SOLVED: To provide a microporous film roll capable of reducing occurrence of curvature and sag on a taken-out olefin-based resin microporous film.SOLUTION: Provided is a microporous film roll which is formed by winding an olefin-based resin microporous film around a lead body, in which difference of adjacent outer peripheral lengths is equal to or less than 1.5 mm on outer peripheral length of the microporous film roll measured for 10 mm interval from one end to the other end, difference between maximum outer peripheral length and minimum outer peripheral length is equal to or less than 3 mm, and the microporous film roll satisfies the formula (1): [(D/2-d/2)/w]×[(h-h)/t]<200. (In the formula, D is average outer diameter (mm) of the microporous film roll, d is average outer diameter (mm) of the lead body, w is average width (mm) of the olefin-based resin microporous film, his maximum outer peripheral length of the microporous film roll, his minimum outer peripheral length of the microporous film roll, and t is average thickness (mm) of the olefin-based resin microporous film).SELECTED DRAWING: Figure 1 |
