| 摘要 |
PURPOSE:To provide a method of extrusion-molding a thermoplastic resin pipe free from differences between high and low positions in cooling the inner face of a thermoplastic resin pipe, and capable of cooling uniformly the inner surface of the thermoplastic resin pipe, and thus producing no stresses in the pipe wall. CONSTITUTION:This is a method of extrusion-molding a thermoplastic resin pipe by introducing and then cooling thermoplastic resin pipe 21 extruded from an extruding mold 1 to a cooling tank 3, wherein a cooling mandrel 4 is disposed within a thermoplastic resin pipe 21, and the cooling mandrel 4 is composed of a cylindrical elastic material layer 42 with a good heat conductivity on the outer face of a cooling mandrel main body 41 in order to cool the elastic material layer 42 by flowing cooling water within the cooling mandrel main body, so that the inner face of the thermoplastic resin pipe 21 is cooled by permitting it to be in contact with the elastic material layer 42. |
