PREFORM FOR SMALL FLAT CONTAINER AND SMALL FLAT CONTAINER

摘要

To solve the limit of wall-thickness adjustment of a preform for a small fl at container by a flat core by forming the outer side of a step-up-formed large-wall-thickness shell part with reducing wall thickness. A preform 1 fo r a small flat container whose inside diameter is completely circular and restricted to a small value is used. A shell part 12 is step-out-formed from the bounda ry between a neck part 11 and a shell part 12 so that the shell part 12 has a diameter larger than the neck part 11. A difference is provided between wall thickness of forward/backward sides 12a and right/left sides 12b of the shel l part 12 by forming the outer side of the shell part into an ellipse form or the like from the underside of step-out at with reducing wall thickness. A stepped ou t part 14 is left like a disk in the underside of the neck part.