High durability PVDF porous membrane, method for producing the same, and cleaning method and filtration method using the same

摘要

The present invention provides a PVDF porous film, which has high water permeability and high chemical resistance to washing chemicals and the like that has been difficult to realize with conventional polymer porous films, and which can be used over a prolonged period of time; and a method of producing the same and the like. Namely, the present invention provides a porous film in which the degree of crystallization of the 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 (% · m 2 /g) or more but not more than 2000 (% · m 2 /g). In addition, the present invention provides a method for producing a porous film comprising: producing a porous film having a PVDF resin as a main component thereof by extruding, from a molding nozzle, a film-forming solution which at least comprises a hydrophobic polymer component having a PVDF resin as a main component thereof, a hydrophilic polymer component and a common solvent for both the hydrophobic and hydrophilic polymer components, and solidifying the film-forming solution in a solution having water as a main component thereof, 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.