| 摘要 |
PURPOSE:To obtain a corrugated sheet material, which is fully flexible in the repeating direction of corrugations and favorably air-permeable, by a structure wherein each corrugation is cut in pieces by channels, which run normal to the corrugation, and an opening is provided at the side face of the cut corrugation. CONSTITUTION:The corrugated plastic film or sheet concerned is substantially made in the form of a corrugated sheet or film having the thickness of from several millimeters to several ten micromillimeters out of all the film-making thermoplastic resin such as polyethylene, polypropylene or the like by injection molding or other means. Stock resin may well contain additives such as plasticizer and the like, when necessary. As essential constitution, channels, which run so as to meet corrugations, are equipped. The channels run as a rule from the end of the sheet to the end so as to pass through the sheet. However, as the case may be, the channels can arbitrary be cut halfway. In the extreme case, the corrugations and the channels are cut each other by the half pitch of the corrugations, resulting in showing the rhombiform external appearance. A through hole is formed at the edge face of each corrugation cut by each channel or at one side face or both side faces, which are parallel to the channel, of the corrugation. The corrugations 2, 2... constituting a thermoplastic sheet 1A produce a large number of independent roof-like parts 2a, 2a..., each of which is cut in a piece by the channels 3, 3... traversing perpendicular to the corrugation. At the same time, through holes 4, 4... are bored at the edge face on this side of the figure of the respective independent roof-like parts. In this case, the depth of the bottom part (the through part) 2b of the corrugation (the distance from the crest of the wave to the bottom of the wave) is equal to the depth of the channel 3. |
