Abstract: A method of making a plastic container having a threaded wide-mouth finish includes providing a preform having at least an exterior surface of molded polyester construction. The preform is placed in a mold cavity having a first portion for forming a container body, a second portion adjacent to the first portion for forming a cylindrical finish wall without threads, and a third portion adjacent to the second portion for forming a trim dome or moil. The preform is expanded within the mold cavity to form a one-piece intermediate product that includes a body, a cylindrical wide-mouth finish wall and a moil. After removing the intermediate product from the cavity, the moil is severed from the end of the finish wall. At least one thread is then formed on the finish wall by engaging the finish wall with at least one thread-forming tool, which may be heated to facilitate the forming operation.

Abstract: A method of making a preform assembly including providing a finish ring of plastic construction, placing the finish ring onto a core pin, introducing a preform polymer into a mold cavity that includes the core pin, and compression molding the preform polymer to the finish ring. A resulting preform assembly, and container assembly blow-molded from the preform assembly, are also disclosed.

Abstract: A method of producing preforms for blow molding containers includes producing polyester polymer by melt phase polymerization and compression molding preforms of the polyester polymer without solidifying the polyester polymer prior to compression molding the preforms. This process has the advantage of eliminating the conventional intermediate steps of solidifying the polymer in the form of pellets, shipping the pellets to the preform manufacturer and then remelting the polymer. Furthermore, because the preforms are produced directly from melt phase polymer, the polymer can have a low intrinsic viscosity of 0.65 or less, which is particularly useful for blow molding containers for low pressure, low temperature applications.