POROUS POLYPROPYLENE FILM ROLL

The porous polypropylene film roll of the present invention is a porous polypropylene film roll of which a porous polypropylene film comprising a polypropylene resin and having the average value of the porosities, µave, of 45 to 90% is wound around a core, and the unevenness of the thickness in the film machine direction is not more than 15%. The porous polypropylene film roll of the present invention has not only excellent air permeability and porosity but also excellent thickness uniformity, and therefore a porous polypropylene film roll which can efficiently utilize the performance of an electric storage device and is suitable for a separator for an electric storage device is provided.