| abstract |
It is intended to provide a porous PVDF film, which has a high water permeability and such a high durability to chemicals such as washing chemicals that can be hardly achieved by the existing porous polymer films and can be used over a prolonged period of time, a method of producing the same and so on. Namely, a porous film wherein the degree of crystallization of a PVDF resin is 50% or more but not more than 90%, and the product of the degree of crystallization of the PVDF resin and the specific surface area of the film is 300 (%·m2/g) or more but not more than 2000 (%·m2/g). A method of producing a porous film comprising extruding a film-forming solution, which at least comprises a hydrophobic polymer component having a PVDF resin as the main component, a hydrophilic polymer component and a common solvent for both of the hydrophobic and hydrophilic components, from a molding nozzle, and solidifying the same in a solution comprising water as the main component to thereby produce a porous film having the PVDF resin as the main component, wherein polyethylene glycol having a weight-average molecular weight of 20,000 or more but not more than 150,000 is used as the hydrophilic polymer component. |