MICROPORE FORMING AGENT FOR POROUS RESIN FILM, AND COMPOSITION FOR POROUS RESIN FILM CONTAINING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a micropore forming agent for a porous resin film, capable of providing a resin composition which provides the porous resin film suitable for use in electrical applications such as a capacitor and battery separator.SOLUTION: A micropore forming agent for a porous resin film is composed of inorganic particles including at least one metal of alkali earth metal, silicon, titanium and aluminum. The inorganic particles are inorganic particles surface-treated with a surfactant (A) and/or a compound (B) having chelating capability to the metal, and satisfy the relationships of: (a) 0.1≤D50≤1.5 (μm) (D50: average particle diameter of cumulative weight 50% calculated from the large particle side in microtrack FRA); (b) Da≤20 (μm) (Da: maximum particle diameter in microtrack FRA); (c) 3≤Sw≤60 (m/g) (Sw: BET specific surface area by nitrogen adsorption method); and (d) Ir≥1.0×10(&OHgr;cm) (Ir: volume resistivity of hydrochloric acid insoluble content).