| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing a biaxially oriented thermoplastic resin pipe, by which a biaxially oriented molding process can be smoothly started and a finished product showing an outstanding strength in the axial and the peripheral direction can be continuously obtained. SOLUTION: This method for manufacturing a biaxially oriented thermoplastic resin pipe comprises the steps to adjust the temperature of a thermoplastic resin pipe 21 extruded from a mold 12 of an extruder 11 to a specified orientation temperature level, to expand the diameter of the pipe 21 by making it pass over a diameter expansion mold 17 connected to the mold 12, and to orientate/mold the diameter-expanded pipe 21 while taking it up with the help of at take-up unit. The diameter expansion mold 17 is of such as structure that headless conical parts 171 and 173 with diameter gradually expanded in a direction where the pipe 21 proceeds are separately formed in a multi-stepped fashion. In addition, the headless conical parts 171 and 173 are connected to each other by an intermediate columnar part 172 which maintains the same diameter in the direction where the pipe 21 proceeds. |
