METHOD FOR MANUFACTURING MULTI-LAYER SEPARATOR

One aspect of the present invention provides a method of manufacturing a multi-layer separator, which includes (a) extruding a first composition including a first polyolefin and a first pore forming agent to obtain a first sheet; (b) extruding a second composition including a second polyolefin and a second pore forming agent to obtain a second sheet; (c) stretching each of the first sheet and the second sheet in the machine direction (MD) to obtain a first precursor film and a second precursor film; (d) laminating the first precursor film and the second precursor film to obtain a stacked structure; and (e) stretching the stacked structure in the transverse direction (TD), and then removing the first pore forming agent and the second pore forming agent from the stacked structure.