| 摘要 |
PROBLEM TO BE SOLVED: To provide a fine punch sheet of such a form that can control breathability and penetration of raindrops. SOLUTION: A fine punch sheet and a method of punching are provided comprising punches of 'a cut punched form' without absence of a sheet material at the punch, only by making a cut on the sheet material instead of making a holes by a punch, a drill or the like. Thus, the fine punch sheet serving as a restraint valve which can make air permeability from a rear to a front of the sheet smaller than that from the front to the rear in an air flow with the sheet as a border is obtained. In addition, when the sheet is used to cover agricultural soil or the like, it serves to appropriately restrain rain from penetrating without losing an exchanging function between air in the soil and the open air.
|
