| 摘要 |
PURPOSE:To enable a high quality bottomed parison with thick wall to be molded, and to achieve the mold release at the bast condition by a method in which thermoplasticized resin in fed in a parison mold at low pressure, and further the residual resin in an extruding path is pushed into the parison mold at high pressure. CONSTITUTION:The extruding path 12 between an extruding chamber 11 and the space part 16 in a parison mold is opened or closed by lifting and lowering a pushing plunger 13, thereby controlling the resin flow in the chamber 11. The cross section of the extruding path 12 is enlarged, and the prescribed amount of the resin with high density and high viscosity is quickly supplied into the space part 16 in the parison mold at low pressure and low speed and at the temperature suitable for blow molding. For the shortage of the resin, the residual resin in the extruding path 12 is pushed into the space part 16 in the parison mold at high pressure by the pushing plunger 13, whereby the molding is completed. Consequently, the bottomed parison of desired shape may be easily molded, and since when the resin is extruded from the extruding path 12, the rising of the resin temperature is slight, the mold release is achieved at the best condition suitable for nest process. Thus, blow molding is effectively carried out. |
