| 摘要 |
PURPOSE:To form a striped pattern around a cylindrical base by a method wherein, when molten resin is deposited over the periphery of the cylindrical base while the base is being moved out from a through hole by the use of a die having an annular resin extrusion port around the through hole, the void where the cylindrical base contacts the molten resin is periodically reduced in pressure. CONSTITUTION:A die D includes a first sleeve 5 with a guide hole 2 and a second sleeve 6 with a through hole 3, in which a die body 7 encircles the sleeve 6 and an annular extrusion port 9 is formed around the hole 3. The internal diameter of the hole 2 is approximately equal to the outside diameter of a cylindrical base 1. The internal diameter of the hole 3 is made grater than the outside diameter of the base 1 and the hole 3 is connected to a vacuum pump P. As the base 1, an aluminum lamination tube, etc., can be employed. If resin is extruded, while the base is being moved through the holes 2 and 3, a resin layer 20 is formed over the base 1. If the vacuum pump is turned on/off periodically, thickness of the molten resin layer changes, so that striped pattern is formed. By providing two units of such devices in series, resin layers 20a, 20b can be formed over the outside surface of the base 1. |
