| 摘要 |
PURPOSE:To produce a bottle free from thermal shrinkage at high speed of production by a method wherein a heat-treating step and a cooling step for a PET bottle are incorporated in a stretching step for the bottle and are carried out in such a condition that the outside peripheral surface of the bottle being stretched in a mold is maintained in close contact with the inside wall surface of the mold. CONSTITUTION:While projecting a stretching rod 3 into a parison P, a pressurized fluid (5-30kg/cm<2>) is injected through a nozzle port 21 to form a bottle B. The bottle B is heat-treated for a predetermined period of time while maintaining an internal pressure applied to the bottle B in the mold which is being heated to 80- 250 deg.C by a medium flowing through passage holes 11 provided in the wall of the mold. The heat treatment is preferably conducted for a period of time and at a temperature which is selected in accordance with the degree of surface orientation of the bottle, that is, the bottleneck and bottom parts having a degree of surface orientation DELTAp of not higher than 90-10<-3> are heat-treated at 80-120 deg.C, while the trunk part having a DELTAP of at least 90-10<-3> is heat-treated at 120-250 deg.C. After heat-treating for several seconds, the bottle is solidified through cooling by jetting a cooling liquid while maintaining a slight internal pressure. |
