| abstract |
In the present invention, (S1) a polyolefin, a diluent, an initiator, a hydrocarbon-based crosslinking agent containing at least one alkoxy group and at least one vinyl group, and a crosslinking catalyst are introduced into and mixed with an extruder, and then extruded to graf the alkoxy-containing hydrocarbon system. Preparing a polyolefin composition; (S2) forming and stretching the extruded alkoxy-containing hydrocarbon-based grafted polyolefin composition into a sheet form; (S3) extracting a diluent from the stretched sheet to prepare a porous membrane; (S4) heat-setting the porous membrane; And (S4) cross-linking the heat-set porous membrane. |