| 摘要 |
PURPOSE:To obtain an inexpensive pipe whose periphery is provided with an uneven surface by a method in which a thermoplastic resin pipe is molded while offering a resistance to the pipy resin immediately after being extruded through a die in such a way as to regulate the movement of the resin from its inside to the extruding direction. CONSTITUTION:A resistance is offered to a pipy resin immediately after being extruded through a die from a flange material 78 in such a way as to regulate its movement toward the extruding direction. After passing through the die 72, the pipy resin is temporarily stopped between the die 72 and the flange material and expanded cylindrically there. Since a slight turning force is given to the resin being extruded through the die 72 by the rotation of a screw 34, a spiral uneven shape is formed on the periphery of the resin passing through the flange material 78. If the rotation of the molten resin is controlled, a pipe whose periphery is provided with a circularly uneven shape can be molded. |
