| 摘要 |
PURPOSE:To obtain a porous film having excellent balance of tensile strength and water vapor permeability, high facial strength and excellent tear strength by monoaxial stretching, by combining plural polyethylene materials having specific physical properties, modifying through crosslinking, blending the materials with a filler, molding and drawing under a specific condition. CONSTITUTION:100 pts.wt. total amounts of 50-100 pts.wt. linear polyethylene having <=20/10 minutes melt index, <=70 fluidity ratio and 0.91-0.965 g/cm<3> density and 0-50 pts.wt. branched chain low-density polyethylene having the same melt index, fluidity ratio and density as those of the linear polyethylene is blended with 5-40 pts.wt. ethylene-alpha-olefin copolymer having <0.91 g/cm<3> density, 0.0001-0.1 pt.wt. radical generator and 100-400 pts.wt. filler, molded at 2-8 blow up ratio and at frost line height of 2-50 times ring-shaped slit and stretched at 1.2 ratio to give the objective film having <=90mum thickness, <=50 mm bending resistance in the longitudinal and lateral directions, >=1,500 g/m<2>.24 hr water vapor permeability, >=10 kg/cm<2> Elmendorf tear strength in the longitudinal direction and facial strength shown by the formula. |
