Process for producing polyolefin microporous stretched film with cellulose nanofiber, polyolefin microporous stretched film with cellulose nanofiber, and separator for non-aqueous secondary battery

摘要

The present invention provides a production method and the like of a microporous stretched film having a high puncture strength and the like. The method includes: a first step of melt-kneading a cellulose nanofiber and a polyolefin resin to thereby disperse the nanofiber in the resin; a second step of removing water from a kneaded mixture obtained in the first step; a third step of mixing a plasticizer in the nanofiber and the resin and melt-kneading them to prepare a polyolefin resin composition; a fourth step of extrusion-molding the polyolefin resin composition; a fifth step of stretching an extrusion-molded article obtained in the fourth step to form a film; and a sixth step of extracting the plasticizer from the film.