The present invention is directed to plastic closures for beverage, food, juice, pharmaceutical and like applications, and more particularly to a closure, a package and a method of manufacture that are particularly well suited for high-temperature (e.g., pasteurization, hot fill, asceptic fill and retort) applications.
It has heretofore been proposed to provide a plastic closure for a container, which comprises a plastic cap or shell with an interior liner for sealing engagement with a sealing surface of the container finish. For example, U.S. Pat. No. 4,984,703 discloses a plastic closure that comprises a shell having a base wall with a peripheral skirt and an internal thread for securing the closure to a container finish, and a sealing liner compression molded in situ on the interior of the shell base wall. U.S. Pat. No. 5,451,360 discloses a method and apparatus for compression molding the liner in situ within the closure shell. It has also been proposed to provide plastic resin barrier materials within the sealing liner for resisting transmission of gases (e.g., carbon dioxide and oxygen), water vapor and/or flavorants through the liner. For example, U.S. Pat. No. 6,371,318 discloses a plastic closure and method of manufacture in which the liner is compression molded in situ on the interior surface of the closure base wall, and includes a multiplicity of alternating layers of matrix polymer such as EVA and barrier polymer such as EVOH. U.S. Pat. No. 6,399,170 discloses a plastic closure and method of manufacture in which the liner is compression molded in situ on the interior surface of the closure base wall, and includes a dispersion of barrier polymer platelets, such as EVOH, dispersed within matrix polymer such as EVA.
It is desirable to provide a closure and liner construction, a method of closure manufacture, and a closure and container package that are particularly well adapted for high-temperature applications. Such high-temperature applications include, for example, applications in which the container is filled with product while the product is hot, such as so-called hot fill and asceptic fill applications. High-temperature applications also include applications in which the filled package is subjected to pasteurization or retort after filling. During retort applications, for example, the filled package may be subjected to a temperature of 265° F. for fifteen minutes. High-temperature situations can also occur when a package is filled with a carbonated beverage and subjected to storage under high-temperature conditions, in which the internal pressure within the container can increase dramatically. In all of such high-temperature situations, the container closure is subjected to elevated internal pressure, which tends to distort or dome the closure base wall and lift the sealing liner away from sealing engagement with the container finish.
Copending U.S. application Ser. No. 09/994,554, filed Nov. 27, 2001 and assigned to the assignee of the present application, discloses a plastic closure that has particular utility for such high temperature and retort applications. The closure includes a shell having a base wall and a skirt with one or more internal threads for securing the closure to a container finish. In some embodiments, a plastic disk is loosely captured within the closure shell. An annular ring extends axially from the disk adjacent to but spaced from the periphery of the disk. A resilient liner is molded onto the disk over at least the central portion of the disk and over the ring on the disk. The ring urges the liner into sealing engagement with the radially inner edge and the axial end of the container finish when the closure is secured to the container finish. In some embodiments of the closure disclosed in the copending application, the disk includes an annular rib around the periphery of the disk, with the liner extending around the inner periphery of the rib. The disk thus urges the liner into sealing engagement with the inner and outer edges of the container finish as well as the axial end of the container finish. When a filled package that includes such a closure is subjected to elevated temperatures, during retort applications for example, the liner is maintained in sealing contact with the container finish.
Although the closure, package and method of manufacture disclosed in the noted copending application address and overcome problems theretofore extant in the art, further improvements remain desirable. In particular, in embodiments in which the liner is disposed on a separate disk retained within the closure shell, there are concerns associated with potential accumulation of debris and/or liquid product in the space between the disk and the base wall of the closure shell, which can promote growth of mold or other undesirable matter. It is therefore a general object of the present invention to provide a closure, a closure and container package, and a method of manufacture that include facility for flushing the area between the closure shell and the liner disk after the closure has been assembled to the container.
A plastic closure in accordance with a first aspect of the present invention includes a plastic closure shell having a base wall with a central opening and a skirt with at least one internal thread or bead for securing the closure to a container finish. A plastic disk is retained within the shell parallel to but spaced from the base wall. The disk includes a plurality of axially extending spacer elements around the disk to engage an underside of said base wall and space the disk from the base wall of the shell, and angularly spaced fingers that extend from the disk through the central opening of the base wall to retain the disk within the shell. A resilient liner is disposed on an underside of the disk for sealing engagement with the container finish.
A two-piece plastic closure in accordance with another aspect of the present invention includes a plastic closure shell having a base wall with a central opening and a skirt with at least one internal thread or bead for securing the closure to a container finish. A plastic disk is retained within the shell parallel to but separate from the base wall. The disk includes an axially extending bead composed of a plurality of angularly spaced bead segments around a peripheral portion of the disk to space the disk from the base wall of the shell. A plurality of angularly spaced fingers extend from the disk through the central opening of the base wall concentrically with the bead and retain the disk within the shell. A resilient sealing liner is molded in situ on an underside of the disk for sealing engagement with a container finish.
A closure and container package in accordance with a further aspect of the present invention includes a glass or plastic container having a finish with at least one external thread. A plastic closure includes a closure shell having a base wall with a central opening and a skirt with at least one internal thread engaged with the external thread on the container finish. A disk is disposed within the shell. The disk includes a plurality of angularly spaced axially extending spacer elements around the disk in abutting engagement with the base wall and spacing the disk from the base wall. Angularly spaced fingers extend through the opening in the base wall to retain the disk within the shell when the closure is removed from the container finish. A resilient liner is disposed on an underside of the disk in sealing engagement with the container finish around the periphery of the disk.
A method of making a closure and container package in accordance with yet another aspect of the present invention includes providing a glass or plastic container having a finish with at least one external thread, and a closure that includes a shell with a skirt having at least one internal thread. The closure shell has a base wall with a central opening, and a plastic disk is retained within the shell parallel to but separate from the base wall. The disk includes a plurality of angularly axially extending spacer elements, preferably in the form of an axially extending bead composed of a plurality of spaced bead segments around a peripheral portion of the disk, to space the disk from the base wall of the shell. A plurality of angularly spaced fingers extending from the disk through the central opening of the base wall and retain the disk within the shell. A resilient liner is disposed on an underside of the disk. The container is filled with a fluid product, and the closure is secured to the container with the liner in sealing engagement with the container finish. Fluid is then directed into the central opening of the base wall between the fingers, between the base wall and the disk, through the gaps between the spacer elements on the disk, and then between the closure skirt and the container finish to flush any debris or liquid product that may have entered this area during handling of the closure or filling of the container.
The invention, together with additional objects, features and advantages thereof, will be best understood from the following description, the appended claims and the accompanying drawings in which:
The disclosure of above-noted U.S. application Ser. No. 09/994,554 is incorporated herein by reference.
Disk 30 is disposed within closure shell 28. Disk 30 includes a generally flat disk body 46 having a circular periphery with an axially upwardly extending peripheral bead, which is formed in this embodiment by a plurality of angularly spaced circumferentially aligned bead segments 48, 49, as best seen in FIG. 4. Bead segments 48, 49 are disposed axially to engage the undersurface of closure base wall 34 to space disk body 46 from the base wall. A plurality of angularly spaced flexible resilient spring fingers 50 extend upwardly from the upper surface of disk body 46. As best seen in
Sealing liner 32 preferably is flexible and resilient, and is disposed on the underside or undersurface of disk body 46. Liner 32 preferably is compression molded in situ onto disk 30 while disk 30 is captured within the closure shell. That is, disk 30 is first placed within the closure shell and captured by snap fit of fingers 50 over base wall shoulder 44, and liner 32 is then compression molded in situ onto the disk. Alternatively, but less preferably, the liner may be compression molded onto the disk employing an assembly fixture 60 such as that illustrated in
After container 22 has been filled with material, typically fluid material, closure 26 is secured over the finish of the container. Rotation of closure shell 28 to engage threads 38, 40 pushes disk 30 and liner 32 over the axial end of the container finish. If disk 30 is loosely retained within the shell, as is preferred, disk 30 and liner 32 do not rotate with respect to the container finish after engagement with the finish, but merely are axially pressed onto the container finish as shell 28 is threaded onto the finish. Liner 32 is pressed into sealing engagement against the axial end of the container finish, against the radially inside edge of the container finish by a bead 54 on disk body 46, and against the radially outer edge of the container finish by a ring 56 that extends around the outer periphery of disk body 46. Ring 56 has a wiper bead 58 (
Container 22 (
There have thus been disclosed a plastic closure, a closure and container package, and a method of manufacture that fully satisfy all of the objects and aims previously set forth. The closure and package possess superior sealing capabilities, particularly in high-temperature applications such as hot-fill, asceptic-fill, pasteurization and retort applications. The closure and package are also adapted to be flushed with fluid after filling and application of the closure to remove debris and any excess liquid that may have resulted from the filling operation. The invention has been described in conjunction with a number of aspects and embodiments, and a number of modifications and variations have been discussed. Other modifications and variations will readily suggest themselves to persons of ordinary skill in the art. Disk 30 preferably is loosely retained within the closure so that the disk and sealing liner will remain stationary with respect to the container finish while the closure shell is turned onto and off of the finish. This helps prevent damage to the liner. However, disk 30 could be non-movably secured to the closure shell in accordance with the broadest aspects of the invention as long as a path is provided for flushing fluid between the disk and the shell. The invention is intended to embrace these and all other modifications and variations as fall within the spirit and broad scope of the appended claims.
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Number | Date | Country | |
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20040108294 A1 | Jun 2004 | US |