| 摘要 |
PURPOSE:To make it possible to form monolithically a spiral uneven stripe on the inside of a tube under the extruded condition, by pulling the tube extruded from an extrusion molding machine in the axial direction, allowing a forming roll to bite, inside the tube moving in the axial direction, into the thickness in a specified depth and rotating eccentrically the forming roll. CONSTITUTION:Each molten resin is respectively supplied into a molten resin supplying hole 7 for forming an inner tube (a) and a molten resin supplying hole 9 for forming an outer tube (b) and extruded from nozzles 6' and 8' respectively and both tubes are laminated to form a laminated tube. The laminated tube is kept in a cylindrical shape by a compressed air sent from an air supplying path 28 and passed through a cooling water bath to cool and solidify the tube, which is successively pulled out by a take up machine and wound on a winding roll. A forming roll 15 rotating eccentrically inside the molten tube laminated at the outlet of the extrusion molding machine is contacted under pressure on its inside of the laminated molten tube. The concave part 29 formed by pressing the forming roll 15 becomes spiral because the formed tube moves straight. A round or polygonal stripe can be thereby spirally formed monolithically inside of the tube at the stage when the tube is extruded from the extrusion molding machine. |
