| 摘要 |
Provided is a method for manufacturing a high-quality porous film. Here, while the porous film is being manufactured through forming micropores by stretching, a raw film is prevented from slipping on the surfaces of the respective rolls as much as possible even though the raw film includes oil or liquid paraffin as a solvent. The method is for manufacturing a porous film through forming micropores by successive biaxial stretching. A tensile force applied to the raw film F transferring from the longitudinal stretching machine (10) to the transverse stretching machine (50) is set not less than a stretching force necessary for the longitudinal stretching, and thus the raw film is prevented from slipping on a contact surface between the raw film and each roll of the longitudinal stretching machine (10).
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