| 摘要 |
<p>A forgery preventive sheet, in which thread is exposed to window opening portions provided on a surface of the sheet, and which is free of wrinkles even when continuously wound and is excellent in design. The forgery preventive sheet is a two-layer combination paper composed of at least two layers, that is, an outermost paper layer and a paper layer other than the outermost paper layer, the outermost paper layer being provided with spaced window opening portions in a longitudinal direction of the outermost paper layer, the window opening portions being formed therein with watermarks, which include characters or images, the outermost paper layer and the paper layer other than the outermost paper layer having thread interposed therebetween to expose the same in the window opening portions. A ratio between a length (X) of the window opening portions in the longitudinal direction of the sheet and a length (Y) of non-window opening portions positioned between the adjacent window opening portions is made 3:1 to 1:2 whereby wrinkles are surely prevented from generating at the time of winding and the sheet is preferable in design.</p> |
