METHOD FOR PRODUCING POROUS FILM, AND POROUS FILM

PROBLEM TO BE SOLVED: To provide a method for producing a porous film which has a craze having controlled position and size and suppresses extension of cracks, and to provide a porous film capable of produced by the same.SOLUTION: There are provided a method for producing a porous film includes a shaping step P1 of producing a resin film having a plurality of recesses on at least one surface and a stretching step P2 of applying a tensile stress parallel to a surface direction to the resin film; and a porous film in which a plurality of recesses having V-shaped or U-shaped cross sections are formed on at least one surface and a plurality of holes are formed between the bottom of the recess and a surface in an opposite side to the surface on the side which the recess is formed.SELECTED DRAWING: Figure 1 【課題】 位置および大きさが制御されたクレーズを有しクラックの伸展が抑制される多孔質フィルムを製造する方法、及び、当該方法で製造し得る多孔質フィルムを提供することを目的とする。【解決手段】 少なくとも一方の面に複数の凹部を有する樹脂フィルムを作製する賦形工程Ｐ１と、面方向に平行な引張応力を樹脂フィルムに加える引っ張り工程Ｐ２と、を備える多孔質フィルムを製造する方法、及び、少なくとも一方の面に断面がＶ字状またはＵ字状の複数の凹部が形成され、前記凹部の底と前記凹部が形成される側の面とは反対側の面との間に複数の空孔が形成される多孔質フィルムとする。【選択図】 図１