Method for producing hollow molded article and injection stretch blow molding machine

An injection stretch blow molding machine comprising:

• an injection molding section in which an injection molding mold combines an upper mold, a lower mold, a rotary plate, and a lip mold, for use in injection molding a preform, the lip mold having a first portion and a second portion, the first portion of the lip mold being secured to the rotary plate and the second portion of the lip mold sized to be received within the lower mold,
• a blow molding section that includes a stretching rod configured to stretch the preform which has been injection molded by the injection molding section, where a blow molding mold that combines a blow mold and the lip mold for blow molding a hollow molded article is disposed,
• an ejection section configured to eject the hollow molded body molded in the blow molding section from the lip mold and discharging it outside the machine, wherein
• the injection molding section, the blow molding section and the ejection section are arranged on a base, and
• the hollow molded article manufacturing processes are performed simultaneously,
• the injection molding section is a section configured to perform
• an injection cooling process of allowing the preform to be brought into contact with the injection molding mold to solidify a surface layer of the preform, and
• a preform conveyance process of releasing the preform, cooled by the injection cooling process, from the injection molding mold and conveying the preform, to the blow molding mold with the preform being in a state in which the surface layer of the preform is softened by receiving heat from an inner layer of the preform,
• the blow molding section is a section configured such that the preform released from the injection molding mold is disposed in the blow molding mold with the preform being in a state in which the surface layer of the preform is softened by receiving heat from an inner layer of the preform, and
• the stretching rod includes a cooling unit configured to cool a tip of the stretching rod, which is allowed to be in contact with a bottom of the preform, at a temperature ranging from 50° ° C. to 90° C. with the preform being conveyed from the injection molding mold to the blow molding mold in a softened state in which a temperature of the surface layer of the preform is raised by receiving the heat from an inner layer of the preform.