A method of producing a resin container includes injection-molding a resin intermediate molded body of bottomed cylindrical shape as a first injection-molding, injection-molding a resin material outside the intermediate molded body as a second injection-molding, to produce a multilayer preform in which a resin layer is layered on an outer peripheral side of the intermediate molded body, and blow-molding the preform in a state of containing residual heat from injection-molding to produce a resin container having a bottom portion thicker in wall thickness than a body portion. A portion of the inner peripheral side of the intermediate molded body, the portion reaching a bottom portion of the intermediate molded body, has a tapered region in which the wall thickness increases toward the bottom portion.

A preform manufacturing apparatus includes an injection molding unit, a post-cooling unit, and a taking-out unit. The post-cooling unit includes a first mold which accommodates the preform inside and which contacts the outer surface of the preform; and a second mold which is inserted into the preform and which is provided with at least a cooling rod having an internal flow path for compressed air and a tip piece which is attached to a tip side of the cooling rod. The tip piece has a shape corresponding to a bottom of the preform and includes a mold surface that receives the bottom, and an opening formed on a base end side of the mold surface and communicating with the flow path of the compressed air. The post-cooling unit cools the bottom of the preform while pressing the bottom of the preform against the first mold with the mold surface of the tip piece, and cools a body portion of the preform while pressing the body portion against the first mold with the compressed air passing through the opening.

A manufacturing apparatus for manufacturing a resin container, the manufacturing apparatus includes an injection molding part, a temperature adjustment part, a blow molding part, a take-out part, and a rotation plate. The temperature adjustment part includes a first temperature adjustment mold into which the preform is inserted, the first temperature adjustment mold being configured to cool the preform from an outer surface of the preform, a second temperature adjustment mold into which the preform is inserted, the second temperature adjustment mold being configured to cool the preform from an inner surface of the preform, and wherein, in the temperature adjustment part, the preform is cooled so that at least the outer surface temperature of the preform is lowered within a temperature range from 10 C. to 50 C. as compared to the outer surface temperature of the preform when the preform is carried into the temperature adjustment part.

A container treatment system includes a production machine for preforms, a blow molding machine and at least one heat exchange device. The production machine and the blow molding machine are interlocked with one another, and the at least one heat exchange device is configured for heat exchange between the production machine and at least one component of the container treatment system.