| abstract |
A base material for a separator for a nonaqueous electrolyte secondary battery or a laminate separator for a nonaqueous electrolyte secondary battery, which comprises a polyolefin resin as a main component and a porous film containing a phosphate ester in an amount of 5 ppm or more and 700 ppm or less in a mass ratio with respect to the mass of the whole porous film The nonaqueous electrolyte secondary battery is excellent in rate property retention. |