Injection mold for injection stretch blow molding machine, method for molding preform, preform, method for molding container, and container

Abstract

According to the present invention, in order to improve the productivity of an injection stretch blow molding machine, when a core mold is lifted during mold opening at an injection molding part of the injection stretch blow molding machine, stress is dispersed so as not to concentrate at an area where the thickness changes between a preform opening and a preform body so that the preform body is inhibited from being lifted at a skin layer formed in the area where the thickness changes between the preform opening and the preform body. In a preform () where a skin layer () at the surface has a lower temperature than a middle layer () so as to allow a preform body () and a preform bottom () to expand and deform from the inside of the preform toward the outside of the preform, the skin layer () bridging between the inner surface of the preform body () and the inner surface of the preform opening () is formed in a tapered shape that opens upward at an outward slant with respect to an extension line () of the inner surface of the preform body () extending above the skin layer () so that, during the lifting of the core mold, the stress exerted from the preform body () is dispersed at a stress dispersing plane section () formed with the skin layer ().