Patent ID: 8916644

Claim:
A polypropylene resin composition for use in the formation of a microporous membrane comprising an ultra-high-molecular-weight propylene homopolymer (A) that satisfies the following requirements (1) to (4): (1) the intrinsic viscosity [η] measured with a decalin solution is 7 dl/g or more and less than 25 dl/g; (2) the mesopentad fraction as measured by 13 C-NMR (nuclear magnetic resonance) ranges from 90.0% to 99.5%; (3) the melting point as measured with a differential scanning calorimeter (DSC) ranges from 153° C. to 167° C.; and (4) in an elution temperature-elution volume curve measured by temperature-rising elution fractionation (TREF) using o-dichlorobenzene, the maximum peak has a peak top temperature in the range of 116° C. to 125° C. and a half-width of 7.0° C. or less.