TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Composition: The water content of the coating material is less than or equal to0.7 wt.% as measured by the Karl Fischer method.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Composition: The water content of the coating material is less than or equal to0.7 wt.% as measured by the Karl Fischer method.    TECHNOLOGY FOCUS - POLYMERS - Preferred Component: The porous base is a non-woven fabric or netlike substance comprising polyester, acrylic, polyamide, polyimide, vinylon, polyethylene naphthalate or cellulose, glass, ceramics or metal. The porous base is a microporous resin film (1) that only has through pores (1a) formed in the direction vertical to the film surface in a manner virtually free from any shielding structure between one side of the film and the other side. The resin structure is a porous resin structure. It comprises a resin structure having melting point of less than or equal to145degreesC. The resin composing the resin structure is soluble in amide solvents, ketone solvents or furan solvents. The electronic component is a lithium ion secondary battery, polymer lithium secondary battery, aluminum electrolytic capacitor or electric double-layer capacitor. The porous base is a microporous resin film that has through pores with an average diameter of less than or equal to50 microns running through the film in the direction vertical to its surface in a manner virtually free from any shielding structure and providing an average minimum distance of less than or equal to100 microns between adjacent through pores; a resin structure is provided on one side of and/or inside the film; and filler grains are contained. The microporous resin film has less than or equal to50 g/m2 filler grains contained at its surface and/or on the inside, with the primary average size of said filler grains adjusted to 0.1 to 95% of the diameter of through pores. A porous structure having pores with an average diameter of 0.1-15 microns is formed on one side of the microporous resin film and/or inside through pores. Preferred Property: The filler grains have a melting point of less than or equal to180degreesC or virtually no melting point. A resin film with a peel strength of 0.1-75 (g/20 mm) with respect to the porous resin structure is used as the retainer material. Preferred Material: The resin composing the resin structure is made of polyvinylidene fluoride, vinylidene fluoride copolymer, polyacrylonitrile, acrylonitrile copolymer, poly(methyl methacrylate), methyl methacrylate copolymer, polystyrene, styrene copolymer, polyethylene oxide, ethylene oxide copolymer, polyimide amide, polyphenylsulfone, polyethersulfone, polyether etherketone or PTFE.