| 摘要 |
A technical problem to be solved by this invention is to create, in a synthetic resin bottle, a bottom plate structure that enables the bottom to perform a satisfactory vacuum-absorbing function when a bottom plate draws upward in a manner fully capable of restoring to its original state, to prevent foldlines effectively from extending to peripheral foot, and to secure the self-standing capability for the bottle, even if the foldlines have to develop from the upward drawing deformation of the bottom plate. A primary means of solving this technical problem is a biaxially stretched, blow molded synthetic resin bottle with a bottom comprising a sunken bottom portion, which is formed by contouring and concaving the bottom plate upward in a direction of bottle inside, starting from an inner edge of a ground contact portion disposed along the peripheral foot, the sunken bottom portion being capable of drawing upward in a reversible manner, when internal pressure goes down. This sunken bottom portion comprises an inner peripheral wall portion standing from near an inner edge of the ground contact portion disposed along the peripheral foot, a central concave portion disposed at a center of the bottom, a reversible wall portion in a flat ring shape, which is reversibly deformable into an upward drawing state and which connects an upper end of the inner peripheral wall to the base of the central concave portion, and a circular rib wall portion disposed at a connection between the reversible wall portion and the upper end of the inner peripheral wall portion so as to perform the function as a peripheral rib. |
