| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing fine porous film which ensures favorable productivity and quality stability in the process of thinning by rolling. SOLUTION: The method for manufacturing fine porous film whose composition ratio between polyolefin resin and mineral fine powder is 20/80 to 60/40 with an average pore diameter of 1 μm or lower, a porosity of 65% or more, and a thickness of 100 μm or lower, has the steps of: melting and kneading a raw material composition which is mainly composed of a polyolefin resin, an oil-like plasticizer, and a mineral fine powder of specific surface area of 100 m<SP>2</SP>/g or more which can carry oil-like plasticizer to extrude a sheet-like object; and turn the sheet-like object into a non-porous film by thinning and formation by rolling resulting in the thickness of 100 μm or lower; after which a part or the whole of the oil-like plasticizer is extracted. As for the polyolefin resin, a low-melting-point polyolefin resin with a melting point of 150°C or lower is mainly used, and a high-melting-point 4-methyl-1-pentene copolymer resin with a melting point of 220°C or more or a vicat softening temperature of 170°C or more is interblended 20 to 50% for mixture. COPYRIGHT: (C)2011,JPO&INPIT |
