Abstract: 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.

Abstract: Pressurized plastic container having the appearance of ribs but with substantially reduced creep and without delamination, i.e., having an enhanced shelf life compared to prior art ribbed containers. In multilayer containers, the scribe lines reduce delamination of the layer structure so as to avoid loss of transparency and/or barrier properties. The reduction in creep is particularly useful for smaller volume containers having a greater surface area to volume ratio.

Abstract: A method of forming a multi-layer polyester preform and container, particularly suitable for refillable PET carbonated beverage bottles, having an interior layer of high copolymer polyester material which resists hazing in the preform injection stage, and at least one exterior layer of a polyester to achieve enhanced strain-induced crystallization in the exterior layer during blow molding. The container can withstand higher caustic wash temperatures and exhibits reduced flavor carryover from one product to another.

Abstract: A method of reducing uncontrolled flow of a molten polymer during the packing and cooling stage of an injection molding cycle. A plurality of polymers are injected between a mold cavity and core for making a multilayer plastic article such as a preform, having an exterior layer of a first polymer and an interior layer of a second polymer. In a tapered region of the mold, a minimum width of the tapered region is selected to prevent the second polymer from developing an enhanced leading/trailing edge effect which causes the second polymer to reverse flow during the packing and cooling stage. The method is particularly useful for making preforms for blow molded containers, such as a ketchup container, having a relatively long and thin neck profile. In addition, the method maintains the interior (barrier) layer a minimum distance from the top sealing surface of the preform, in order to prevent defective heat-bonded seals.

Abstract: A preform and container design for a pressurized refillable plastic container, such as a PET carbonated beverage container, having a base section with increased resistance to sprue cracking. Sprue cracking, which may be a problem in warmer climates, is believed to be caused in prior designs by an entrapment of material between the stretch rod tip and the blow mold base during blow molding of the container, which entrapment causes surface defects in the container adjacent the sprue. These surface defects expand during flexing of the container dome, caused by alternating cycles of thermal shrinkage and expansion during container cleaning and filling. Sprue cracking can be reduced by eliminating a depressed dish adjacent the sprue in prior known refillable containers, and may further be reduced by modifications to the preform and container wall thickness ratios and base clearance height.