MANUFACTURE OF SELF-STANDING CONTAINER EXCELLENT IN HEAT AND PRESSURE RESISTANCE

摘要

PROBLEM TO BE SOLVED: To sufficiently secure transparent and wall thickness in a foot end part by making a heating contraction part a tertiary molding of a form containing a bottom-shoulder part close to the valley surface of the final container and the final container by doing secondary blow molding in a mold. SOLUTION: To attain the preferable bottom shape and heating temperature state of a tertiary molding 8, the bottom part 36 and part of a barrel part 35 connected with the bottom part of a secondary molding 6 are heated to be contracted in the height direction and in the circumferential direction. In secondary blow molding, the bottom-shoulder part 40 and its vicinity of a tertiary molding 8 come to a foot end part. Accordingly, it is important to make the part 40 approach the valley part and foot end part of a secondary blow bottom mold as close as possible and to make expansion easy by increasing the temperature of the bottom part 36 sandwiching the part 40 and a cylinder or truncated cone part. Thus, preferable moldability in secondary blow molding can be secured. In this process, it is preferable to make the size of the diameter D1 of the part 40 of the tertiary molding 8 0.3-0.8 time as large as the diameter D0 of a barrel part connected with the bottom part of the final container.