Resin-made container manufacturing method, manufacturing device, and metal mold unit
A manufacturing method of a resin container includes: a first injection molding process for injection-molding a first layer of a preform by using a first resin material, the preform having a bottomed cylindrical shape and including a groove that extends in an axis direction; a second injection molding process for injecting a second resin material into the groove of the first layer, the second resin material having a color that is different from a color of the first resin material, and laminating a second layer on an outer peripheral side or an inner peripheral side of the first layer; and a blow-molding process for blow-molding a preform that includes multiple layers and has been obtained in the second injection molding process in a state where residual heat at a time of injection molding is contained, and manufacturing the resin container having a vertical-striped color pattern formed by using the second layer.
1 . A manufacturing method of a resin container, the manufacturing method comprising:
a first injection molding process for injection-molding a first layer of a preform by using a first resin material, the first layer of the preform having a bottomed cylindrical shape and including a groove that extends in an axis direction;
a second injection molding process for injecting a second resin material into the groove of the first layer, the second resin material having a color that is different from a color of the first resin material, and laminating a second layer on an inner peripheral side of the first layer; and
a blow-molding process for blow-molding a preform that includes multiple layers and has been obtained in the second injection molding process in a state where residual heat at a time of injection molding is contained, and manufacturing the resin container having a vertical-striped color pattern formed by using the second layer,
wherein, in the first injection molding process, a first core mold having a groove formed therein is used to form the groove on the inner peripheral side of the first layer, and
in the second injection molding process, a cavity mold that holds a shape of the first layer is disposed on the outer peripheral side of the first layer, and the second resin material is injected between a second core mold that is different from the first core mold and the groove of the first layer.
2 . The manufacturing method of the resin container according to claim 1 , wherein
in the first injection molding process, a thin film having a small thickness is formed in a portion of the first layer, and
in the second injection molding process, the thin film is broken by injecting the second resin material, and the second resin material is guided to the inner peripheral side of the first layer.
3 . The manufacturing method of the resin container according to claim 1 , wherein
the first resin material and the second resin material are resin materials that have different compositions of colorant and are of an identical type.
4 . A manufacturing apparatus of a resin container, the manufacturing apparatus comprising:
a first injection molding unit configured to injection-molds a first layer of a preform by using a first resin material, the first layer of the preform having a bottomed cylindrical shape and including a groove that extends in an axis direction;
a second injection molding unit configured to inject a second resin material into the groove of the first layer, the second resin material having a color that is different from a color of the first resin material, and laminate a second layer on an inner peripheral side of the first layer; and
a blow-molding unit configured to blow-mold a preform that includes multiple layers and has been obtained in the second injection molding unit in a state where residual heat at a time of injection molding is contained, and manufactures the resin container having a vertical-striped color pattern formed by using the second layer,
wherein, the first injection molding unit uses a first core mold having a groove formed therein to form the groove on the inner peripheral side of the first layer, and
the second injection molding unit disposes a cavity mold that holds a shape of the first layer on the outer peripheral side of the first layer, and injects the second resin material between a second core mold that is different from the first core mold and the groove of the first layer.