| 摘要 |
PROBLEM TO BE SOLVED: To provide an air permeable film having a high total light transmittance and a high water vapor permeability, and to provide a method for producing the same. SOLUTION: This porous film stretched in a length of 1.05-5 times at least in a monoaxial direction comprises 100 pts.wt. of the resin mixture of (A) polyethylene with (B) branched low density polyethylene and 10-300 pts.wt. of an inorganic filler. The polyethylene A is polymerized in the presence of a metallocene catalyst and has a relative strength peak in an elusion temperature range of 70-90 deg.C and a relative strength peak in an elusion temperature range of 90-110 deg.C on an elusion curve by the temperature rise elusion fractionation of the polymer. Therein, the component B is contained in the resin mixture in such an amount that a value (addition amount index) obtained by dividing the content of the component B by the cube root of the melt index of the component B is 5-30, and the porous film has a total light transmittance of >=50% and a water moisture permeability of 1,300-5,000 g/m<2> .24 hr. |
