Polyolefin microporous membrane and its production method, laminated polyolefin microporous membrane, roll and polyolefin microporous membrane evaluation method

摘要

Provided is a polyolefin microporous membrane having excellent winding property and coatability. A polyolefin microporous membrane in which the ratio of the orientation parameter corresponding to the 45° direction and the orientation parameter corresponding to the 135° direction, obtained from values measured by Raman spectroscopy in a 45° direction forming an angle of 45° with respect to the lengthwise direction during film production in a plane parallel to the film surface and a 135° direction forming an angle of 135° in the same direction as the 45° direction, is higher than 0.91 and lower than 1.10.