초록 ▼

A preform and container each having a crystallized neck finish and method of making the same, wherein the method involves introducing a first thermoplastic material into a first mold section to form a substantially crystallized neck portion of a preform, and introducing a second thermoplastic materi

A preform and container each having a crystallized neck finish and method of making the same, wherein the method involves introducing a first thermoplastic material into a first mold section to form a substantially crystallized neck portion of a preform, and introducing a second thermoplastic material into a second mold section to form a substantially amorphous body-forming portion of a preform. The first material may have a substantially higher crystallization rate than the second material, and/or the first mold section may be at a higher temperature than the second mold section. In one embodiment, an indexer carrying two core sets is movable between first and second cavity sets for sequentially molding the neck portions on the first core set in the first cavity set, and then transferring the cores and neck portions to the second cavity set for molding the body-forming portions. The method enables cost-effective manufacture of preforms with crystallized neck finishes and enables production of a thermal resistant finish within a close dimensional tolerance.

대표청구항 ▼

[ What is claimed is:] [1.]1. A method of making a preform by molding, the molding steps comprising:introducing at least one first thermoplastic material into a first mold to form during a first molding step while under first molding conditions a substantially crystallized and opaque first portion o

[ What is claimed is:] [1.]1. A method of making a preform by molding, the molding steps comprising:introducing at least one first thermoplastic material into a first mold to form during a first molding step while under first molding conditions a substantially crystallized and opaque first portion of a preform, the first portion being substantially a neck finish of the preform, the first molding conditions including a first melt temperature and a first mold temperature selected to achieve the substantially crystallized and opaque first portion;transferring the first portion of the preform to a second mold; andintroducing at least one second thermoplastic material into the second mold to form by a second molding step while under second molding conditions different from the first molding conditions a substantially amorphous and transparent second portion of the preform, the second portion being substantially a body-forming portion of the preform, the second material having a relatively low crystallization rate compared to the first material, and the second molding conditions including a second melt temperature and a second mold temperature selected to achieve the substantially amorphous and transparent second portion, the second molding conditions further allowing maintenance of compressive forces to bond the first and second portions;wherein during the first molding step a first molding core is positioned in the first mold for forming the first preform portion on the first core, and during the second molding step the first core and first preform portion are transferred to the second mold for forming the second preform portion over the first core; andcooling the second mold to enable solidification and removal of the first and second preform portions from the molds.