Patent ID: 9616607
Date: 2017-04-11
CPC Classifications: B01D,B29C,B29K,B29L,H01M,Y02E

Claim:
1. A method for manufacturing a polyolefin microporous film, comprising: (a) a step for melt-kneading a composition containing at least a polyolefin resin and a plasticizer, extruding the kneaded composition from a die, and molding a resulting extrudate into a film form; (b) a step for stretching the obtained film in at least one direction after the extruding and molding; (c) a step for extraction by using a solvent to extract and thereby remove the plasticizer from the film after the stretching; and (d) a step for drying the film after the step for extraction, the method for manufacturing the polyolefin microporous film being characterized in that: after the step for extraction and before the step for drying, the film is brought into close contact with a roll that is set to a temperature lower than a boiling point of the solvent; and a liquid lacking an affinity for polyolefin and being of a temperature equal to or greater than the boiling point of the solvent is brought into contact with the film while the film remains in close contact with the roll, whereby the film is heated and dried.