| 摘要 |
PROBLEM TO BE SOLVED: To provide a waterproof ventilation film which has a higher degree of air permeability and waterproofness control than convention and is capable of achieving both air permeability and waterproofness for example at a higher level.SOLUTION: A waterproof ventilation film is configured of a polymeric film having through holes extending from one main face to the other main face, where the through hole is a straight hole the center axis of which extends linearly and has the form that the cross section area vertical to a direction of center axis extension increases from one main face to the other main face of the polymeric film with a 80% or less ratio of a/b of an opening diameter (a) of the through hole in the one main face to an opening diameter (b) of the through hole in the other main face.SELECTED DRAWING: Figure 1 |
