STRETCH BLOW MOLDING METHOD FOR WIDE-MOUTHED CONTAINER AND BLOW MOLD

摘要

PROBLEM TO BE SOLVED: To prevent the deformation of the large diameter mouth part, which as a double-wall structure consisting of inner and outer peripheral walls, of a wide-mouthed container by supporting the inner peripheral wall by a blow mold at the time of stretch blow molding. SOLUTION: The preform of the wide-mouthed container 1 having the large diameter mouth part 11 having the double-wall structure is injection-molded. A downward stepped part 26 is formed to the outer peripheral surface of the boundary of the inner peripheral wall 23 and body part 22 of the preform at the same position as the lower end of the outer peripheral wall of the preform. The inner end of the receiving shelf 34, which is provided to the opening part 32 of the blow mold 31, is positioned at the downward stepped part 26 by closing the mold. In such a state that the lower side of the inner peripheral wall 23 is supported by the receiving shelf 34, the body part 22 is subjected to stretch blow molding on the same surface from the downward stepped part 26 to the outer peripheral wall 25.