| 摘要 |
PROBLEM TO BE SOLVED: To provide a film having perforation arranged in high density with an exact shape.SOLUTION: A micro-perforated polymeric film comprises: (i) opposed first and second surfaces separated by a first prescribed distance; and (ii) a plurality of channels perpendicular to the first and second surfaces. In the micro-perforated polymeric film, a first opening of each channel intersects the first surface and a second opening of each channel intersects the second surface, a diameter of the first opening is larger than a diameter of the second opening, and the second openings on the second surface are spaced apart by a second prescribed distance for each other, ratio of the first prescribed distance to the second prescribed distance is at least 0.25, and further the second surface has an open area of at least 10%. |
