| abstract |
Adding and mixing a polyolefin and a diluent into an extruder and then extruding to prepare a polyolefin composition; Forming a sheet form by passing the extruded polyolefin composition through a die and a cooling casting roll; Stretching the molded sheet; Extracting a diluent from the stretched sheet; And heat setting the sheet from which the diluent is extracted. Including, the heat setting step is performed at -15 ℃ to -2 ℃ compared to the melting point (Tm) of the polyolefin, the heat setting step, the speed of the sheet introduced into the heat setting step in the machine direction of the sheet After increasing the speed up to 20 to 60% of the sheet, it is carried out under conditions of decelerating to 0 to 30%, and after stretching to 20 to 180% of the width of the sheet introduced into the heat setting step in the transverse direction of the sheet, 0 A method of manufacturing a polyolefin separator, a polyolefin separator, and a secondary battery including the same are provided, which is implemented in a mode of reducing to 50%. |