| 摘要 |
<p>PURPOSE: To enhance the heat and pressure resistance of a container by a method wherein two or more legs are radially blow-formed on the bottom of the container, the central part of the bottom is crystallized and the angle of the legs after sterilizing process is kept within a specified range. CONSTITUTION: To obtain a self-supporting container that is blow-formed of biaxially-oriented synthetic resin, two or more legs 6 are radially blow-formed around the central part of a bottom 5 of the container and trough line parts 9 are formed between the legs 6. At least the central part of the bottom 5, the circumference of the central part and parts of the trough line parts 9 near the central part of the bottom 5 are heated by an infrared heater to crystallize them. In addition, an angle 14 of the peripheral part of the central part of the bottom 5 to a part that stretches from the inner edge of the leg 6 toward a ground contact face 13 is at 2-80 deg., most preferably at 4-60 deg., after hot-water treatment of content for heat-sterilization. Thereby, creep-deformation of the container is restrained after the heat-sterilization and the self-supporting stability is ensured.</p> |
