MANUFACTURING METHOD OF POROUS FILM

PROBLEM TO BE SOLVED: To provide a manufacturing method of a porous film capable of stably obtaining the porous film with a high porosity by coagulating a solvent contained in the porous film and to provide a manufacturing method of a separator for a battery. SOLUTION: In the manufacturing method of the porous film comprising a step for removing a low molecular weight material from the porous film containing the low molecular weight material after film formation by using a cleaning solvent, a step for substituting the cleaning solvent contained in the porous film from which the low molecular weight material is removed for a solvent with a higher melting temperature than that of the solvent before used, a step for coagulating the solvent with the higher melting temperature contained in the porous film after the substitution and a step for evaporating and drying the solvent with the high melting temperature at a coagulated state or after liquified, are contained. COPYRIGHT: (C)2007,JPO&INPIT