PRESSURE-RESISTANT THIN SYNTHETIC RESIN CONTAINER AND METHOD OF MOLDING THE SAME

摘要

PURPOSE:To prevent a lowering of falling strength caused by the non-uniformity of wall thickness distribution by providing a step part to the boundary with an outer peripheral wall part to stretch the whole of a bottom surface from the outside of an annular earth surface of the central part of a bottom wall so as to obtain an almost equal wall thickness. CONSTITUTION:The body part 2 of a container 1 is subjected to stretch and blow molding so as to be reduced in its wall thickness up to the outer peripheral wall part 31 of a bottom part 3. The bottom part 3 of the container 1 is constituted of an inner peripheral wall part 32 formed so as to be folded back to the inside from the lower end of the outer peripheral wall part 31 successively reduced in its diameter to become a curved surface, the circular arc annular earth surface 33 generated at the folded-back part of the outer peripheral wall part 31 and the inner peripheral wall part 32 and the bottom wall central part 34 formed almost horizontally so as to be continued to the upper part of the inner peripheral wall part 32. The inner peripheral wall part 32 is formed in a state folded obliquely from the upper end of the annular earth surface 33 and the bottom surface from the outside of the annular earth surface 33 to the central part 34 of the bottom wall is made almost equal as a whole by providing a step part 35 to the boundary with the outer peripheral wall part 31 and formed so as to have a wall thickness almost 4 times that of the outer peripheral wall part.