Double container and molding system

A double container, comprising a container body, wherein

• the container body comprises an inner bag and an outer shell arranged to cover the inner bag,
• one of the inner bag and the outer shell comprises a protruding ridge, and the other of the inner bag and the outer shell comprises a groove,
• the protruding ridge and the groove are configured to be engageable by relative rotation of the inner bag and the outer shell in one direction, and to be disengageable by relative rotation of the inner bag and the outer shell in the other direction,
• the protruding ridge and the groove are engaged such that the protruding ridge interferes with a side wall of the groove, and
• assuming that a width of the protruding ridge and a width of the groove in a natural state at a portion where the protruding ridge and the side wall interfere are W1 and W2, respectively, W1>W2 is satisfied.

A molding system, wherein

• the molding system comprises a transfer device, an injection molding device, a preform supply device, a heating device, a blow molding device, and a container take-out device,
• the transfer device is configured to convey a transfer core along a circulation path,
• the preform supply device is configured to supply a preform, which is configured by covering an inner preform with an outer preform, to the transfer core,
• one of the outer preform and the inner preform is injection-molded by the injection molding device, and the other of the outer preform and the inner preform is supplied from an outside,
• the preform supply device, the heating device, the blow molding device, and the take-out device are arranged along the circulation path,
• the heating device is configured to heat the preform,
• the blow molding device is configured to manufacture a container body by biaxially stretch blow molding the heated preform, and
• the take-out device is configured to remove the container body from the transfer core.