Finish and closure for plastic pasteurizable container

Abstract

Plastic containers subjected to pasteurization processes with a closure having an annular finish support ring that supports an inner surface of the neck finish of the container from inward deformation during pasteurization. The finish support ring can be integral with the closure or can extend from a closure liner. Also disclosed are closures for products that require pasteurization, as well as modified finish threads to provide a surface contact between the finish and closure threads.

Description

FIELD OF THE INVENTION[0001]The present invention relates to plastic container finish and closure systems that are subjected to pasteurization processes.BACKGROUND OF THE INVENTION[0002]Many products require pasteurization to reduce the number of microorganisms that may be present in the product (e.g., food or beverage) during packaging and that can degrade the product. One known pasteurization process is performed after the containers are filled with product and sealed, and involves gradually elevating the temperature of the filled and sealed containers to a desired temperature (e.g., 140° F. for beer), where it is held for a period of time. The container and its contents are then cooled to ambient temperatures where the containers can be labeled, packaged, and stored. Products that are typically pasteurized include fruit juices, milk, and beer.[0003]Although products such as beer have historically been pasteurized in glass bottles, it would be desirable to use plastic containers, ...

AI Technical Summary

Benefits of technology

[0005]In accordance with various embodiments of the invention disclosed herein, there is provided a plastic closure for supporting an amorphous neck finish of a pasteurizable plastic container against deformation. This closure can be used to minimize the finish distortions which normally occur at the high temperatures and pressures involved in the pasteurization process, and as a result, prevent any significant loss of pressure and / or product leakage.

[0006]In further embodiments, the closure can be provided with a liner to enhance seal integrity. Still further, the one or more threads on the container neck finish can be modified to increase the surface contact between the container thread and closure thread, for example, by providing complementary planar thread profiles on the container and closure threads, which provide surface contact and support features. Alternatively, or in addition, one can modify the angle and / or depth of a thread for a greater resistance to deformation. Still further, the container thread may be thickened to further prevent deformation. For example, an increased depth of the container thread, or contact at a region that takes advantage of the greater thread thickness closer to the neck finish wall can be used to withstand the conditions of pasteurization without loss of seal integrity.

[0007]In a further embodiment, a nonvented closure thread is provided so as to prevent nonuniform deformation of the container thread during pasteurization.

[0022]wherein the nonvented closure thread has a planar surface that contacts a planar surface of the vented container thread to provide substantially planar surface contact between the closure thread and the container thread and to support the container thread against deformation during pasteurization.

[0026]wherein the container thread contacts the closure thread at a distance of at least 50% of the radial depth of the thread, as measured from the tip of the thread to a wall of the neck finish, to support the container thread against deformation during pasteurization.

Problems solved by technology

Because a container experiences a range of temperatures during pasteurization, these conditions can cause a plastic container to undergo permanent, uncontrolled deformation.

However, there is a significant increase in cost involved in crystallizing the finish in order to prevent distortion.

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