| 摘要 |
PURPOSE:To contrive to prevent a laminated sheet from being warped by a method in which the surface-plastic layer of the laminated sheet in which prescribed plastic sheets are laminated on both surfaces of a prescribed plastic sheet, is heated and softened by high frequency wave, and said plastic layer is pressed with a creasing, mold, whereby the crease depth reaches substantially its laminate-interface, is provided. CONSTITUTION:A creasing mold 5 is brought in contact with the laminated sheet 6 in which the plastic sheets 6-2 having the dielectric constant of 2.7 or more are laminated on both surfaces of the plastic sheet 6-1 having fold resistance and the dielectric constant of 2.5 or less. When the creasing mold presses said sheet, the pressed part of the plastic sheet 6-2 having the dielectric constant of 2.7 or more is softened and removed by the internal exothermic reaction due to high frequency wave, whereby a crease 10 is formed there. Then, the lower surface of the sheet is changed in some degree, but this improves foldable property and is rather favorable. In this case, since the inserting depth of the creasing mold 5 is regulated so that said inserting depth reaches substantially the laminate interface of the plastic sheet 6-1 having the dielectric constant of 2.5 or less, the crease is not formed on the plastic sheet 6-1 having fold resistance and the dielectric constant of 2.5 or less, and the sheet 6-1 is kept in an original shape. |
