| 摘要 |
PURPOSE:To efficiently prepare a stable product generating no release at all by obstructing the hard resin of an inner layer subjected to co-extrusion in the extrusion molding stage of a tubular body to mold the same into a string state (ridge) and forming the string body into a spiral shape on the inside surface of an outer layer by the straightly advancing tubular body and the rotation of a barrier plate molding a string body to integrally weld the same. CONSTITUTION:The two-layer extrusion of an inside hard synthetic resin and an outside soft synthetic resin is performed by respectively supplying a hard synthetic resin (a) and a soft synthetic resin (b) to material supply ports 8, 9 and longitudinal yarn 23 is inserted in the intermediate part of the outside soft synthetic resin (b) to perform extrusion. Since a barrier plate 25 is rotated in the close contact state with the front end surface of the die of an extruder, the inside hard synthetic resin (a) in an extruded tubular body becomes a state possible to emit only in the notch part provided to the barrier plate 25 to be emitted and molded into to a string shape and, since the barrier plate 25 is rotated, the emitted and molded string is spirally provided to the inside surface of the straightly advancing tubular body. Since two notch parts are formed to the barrier plate 25, the two strings are emitted and two ridges are provided to the inside surface of the tubular body in a screw shape. |
