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 method for manufacturing a resin container includes: performing injection molding on a resin preform; adjusting a temperature of the preform manufactured in the performing injection molding; and performing blow molding on the temperature-adjusted preform to manufacture the resin container. In the performing injection molding, injection molds are opened after completion of filling and pressure holding of a resin material, and the preform is taken out without being cooled in the injection molds after the completion of filling and pressure holding. In addition, in the adjusting the temperature, a refrigerant is introduced into the preform to cool the preform.

A method for heating a preform (1) comprising a body portion (4) extending along a longitudinal axis (A1). The method comprises the following steps: introducing the preform (1) into a heating apparatus (5) comprising an array of infrared emitters (50) arranged in multiple columns (Cj) and rows (Ri); setting power levels of the infrared emitters (50) so as to divide said array into subsets of columns (SCn); andheating the preform while translating it in a direction parallel to the rows (Ri), and simultaneously rotating it around its longitudinal axis, the rotation and translation speeds, and the power levels of the infrared emitters (50) being set so that the power levels of the subsets of columns (SCn) facing zones (42) of the body portion extending longitudinally are different from the power levels of the subsets of columns facing the rest of the body portion, said zones extending relative to one another in a polygonal array.

Provided is a method of producing a container by deforming a heated preform. The method includes: determining at least two formed zones along the container axis in the body, said formed zones being produced using a different quantity of material, each formed zone corresponding to at least one heated zone of a body of the preform; heating the body of the preform using at least two heating elements that each heat one of the heated zones of the body of the preform; deforming the heated preform to form the container; and before the step of heating the body of the preform, adjusting a heating power of each heating element wherein the heating power of each heating element is adjusted as a function of the quantity of material in the formed zone of the body of the container corresponding to the zone heated by each heating element.

A heat treatment device for a PET bottle preform with an integral handle includes an air-cooling knife, a heating furnace, and a transport mechanism. The air-cooling knife is disposed on an outlet side of the heating furnace, the bottle preform is transported into the heating furnace through the transport mechanism, heated in the heating furnace, and transported to the air-cooling knife, and the air-cooling knife jets airflow to and cools a lower end of a handle of the bottle preform, appropriately reducing the temperature at junction of the lower end of the handle and a bottle body so that a gentle transition between the temperature of the bottle body and the temperature of the handle is achieved, and the handle is not easily deformed after the bottle preform is blown, thereby effectively improving the quality of the bottle preform after blown.

A bottle having good mechanical properties and lightness due to its bottom design includes a bottom, a body, and a neck. The bottom has a dome, a coronal arch, an annular seat, a side wall, six main radial grooves, five secondary radial grooves situated between the main grooves, each having an end Ev in the arch, and a peripheral end Ep in the side wall. The bottom is such that the ratio Mf/Vuf, wherein Mf is the weight of the bottom and Vuf is the useful volume of the bottom, is less than or equal to 0.050 g/mL and the ratio .sup.do/H.sup.do, wherein .sup.do is the diameter of the dome at its base and H.sup.do is its apex height along an axis Z, is greater than or equal to 4.4. The invention also relates to a manufacturing method and a mold for the bottle.