Method for manufacturing resin container and apparatus for manufacturing same
A manufacturing method of a resin container having a light-transmitting region and a non-light-transmitting region extending in an axial direction includes: a first injection molding step of injection-molding a first layer of a preform having a convex portion extending in the axial direction using a first resin material having a light-transmitting property; a second injection molding step of injecting a colored second resin material on a surface side on which the convex portion of the first layer is formed and laminating a colored second layer in a region excluding the convex portion of the first layer while exposing the convex portion in the axial direction; and a blow molding step of blow-molding the preform in a state of having residual heat from injection molding.
1 . A manufacturing method of a resin container, the manufacturing method comprising:
injection-molding a first layer of a preform having a convex portion extending in an axial direction on an inner peripheral surface or an outer peripheral surface as a first injection molding, the preform being formed in a bottomed cylindrical shape, using a first resin material having a light-transmitting property;
injecting a colored second resin material on a surface side on which the convex portion of the first layer is formed and laminating a colored second layer in a region excluding the convex portion of the first layer while exposing the convex portion in the axial direction as a second injection molding;
arranging a heating member extending in the axial direction within the preform obtained in the second injection molding to adjust a temperature of a preform as a temperature adjustment; and
blow-molding the preform after the temperature adjustment a state of having residual heat from injection molding to manufacture the resin container,
wherein the resin container has a light-transmitting region extending in the axial direction by shaping the convex portion and a non-light-transmitting region by shaping the second layer, and
in the temperature adjustment, a first distance between the heating member and the convex portion in the radial direction of preform is set to be shorter than a second distance between the heating member and portions other than the convex portion, and at least a position of the convex portion in the circumferential direction of the preform is locally heated.
2 . The manufacturing method of a resin container according to claim 1 , wherein
in the first injection molding, the convex portion is formed on the inner peripheral surface of the first layer, and
in the second injection molding, the second resin material is injected between the inner peripheral surface of the first layer and a mold disposed on an inner peripheral side of the first layer, and the second layer is laminated on the inner peripheral side of the first layer while the convex portion is exposed on the inner peripheral surface of the preform.
3 . The manufacturing method of a resin container according to claim 1 , wherein
in the first injection molding, the convex portion is formed on the outer peripheral surface of the first layer, and
in the second injection molding, the second resin material is injected between the outer peripheral surface of the first layer and a mold disposed on an outer peripheral side of the first layer, and the second layer is laminated on the outer peripheral side of the first layer while the convex portion is exposed on the outer peripheral surface of the preform.
4 . The manufacturing method of a resin container according to claim 1 , wherein
a radial dimension of the convex portion in the first layer obtained in the first injection molding is larger than a thickness of the second layer, and
in the second injection molding, a tip of the convex portion is pressed against a mold of the second layer facing in the radial direction.