Note: Descriptions are shown in the official language in which they were submitted.
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PLASTIC CLOSURE, CLOSURE AND CONTAINER PACKAGE,
AND METHOD OF MANUFACTURE
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.
Background and Obiects of the Invention
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. Patent 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. Patent 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 andlor flavorants through the liner. For example, U.S.
Patent 6,371,318
~ 5 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. Patent
6,399,170
discloses a plastic closure and method of manufacture m which the liner is
compression molded in
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situ on the interior surface of the closure base wall, and includes a
dispersion of barner 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-
S temperature applications. Such high-temperature applications include, for
example, applications
in which the container is filled with product while the product is hat, 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 ftlling. During
retort applications, for
example, the filled package may be subjected to a temperature of 26S °,
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.
IS Copending U.S. application Serial No. 09/994,SS4, filed November 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 zing
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
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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.
Summarv of the Invention
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
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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.
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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
forgers 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
I S area during handling of the closure or filling of the container.
Brief Description of the Drawings
The invention, together with additional objects, features and advantages
thereof, will
he best understood from the following description, the appended claims and the
accompanying
drawings in which:
FIG. 1 is a partially sectioned fragmentary elevational view of a closure and
container
package in accordance with one exemplary preferred embodiment of the
invention;
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FIG. 2 is a fragmentary sectional view on an enlarged scale of the portion of
FIG. 1
within the area 2;
FIG. 3 is a top plan view of the closure shell in the package of FIGS. 1-2;
FIG. 4 is a top plan view of the liner disk in the package of FIGS. 1-2;
FIG. 5 is a sectional view taken substantially along the line 5-5 in FIG. 4;
FIG. 6 is a fragmentary sectional view on an enlarged scale of the portion of
FIG. 5
within the area 6;
FIG. 7 is a fragmentary sectional view on an enlarged scale of the portion of
FIG. 6
within the area 7;
FIG. 8 is a top plan view of a closure disk, similar to that of FIG. 4 but
illustrating
an exemplary modified embodiment, of the invention;
FIG. 9 is a top plan view of a closure disk in accordance with another
exemplary
embodiment of the invention;
FIG. 10 is a fragmentary sectional view that is similar to a portion of FIG. 2
but
illustrates another exemplary embodiment of the invention;
FIG. 11 is a sectional view that diametrically bisects a fixture for molding a
liner on
a closure disk in accordance with an exemplary embodiment of the invention;
FIG. 12 is a fragmentary sectional view that illustrates a modification to the
embodiment of FIG. 10;
FIG. 13 is a fragmentary sectional view that illustrates a modification to the
embodiment of FIG. 2; and
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FIG. 14 is a fragmentary sectional view that illustrates a further embodiment
of the
invention.
Detailed Description of Preferred Embodiments
FIGS. 1-2 illustrate a closure and container package 20 in accordance with one
presently preferred but exemplary embodiment of the invention as comprising a
container 22 having
a cylindrical finish 24. A closure 26 is externally secured to container
finish 24. Closure 26 is an
assembly that includes a closure shell 28, a liner disk 30 and a sealing liner
32. Closure shell 28
includes a base wall 34 and a peripheral skirt 36 having one or more internal
threads 38 for
engagement with one or more external threads 40 on container finish 24.
Closure skirt 36 and
container finish 24 alternatively may include one or more beads for securement
of the closure to the
container, although engaging threads are currently preferred. It is also
contemplated that closure
shell 28 may comprise a dual-wall shell that has an inner wall or skirt with
internal threads 38 and
an outer wall or skirt to coordinate with the sidewall ofthe container.
Closure shell 28 also may
include a tamper-indicating band connected by frangible bridges or a frangible
web to the lower
I S edge of the skirt. (Directional words such as "upper" and "lower" are
employed by way of
description and not limitation with respect to the upright orientation of the
package illustrated in
FIGS. 1 and 2. Directional words such as "axial" and "radial" are employed by
way of description
and not limitation with respect to the axis of the container finish or the
closure skirt, as applicable. )
Closure base wall 34 has a central through-opening 42 (FIGS. 1-3) that is
coaxial with skirt 36.
Opening 42 is surrounded by an axially outwardly or upwardly facing ledge 44
that is recessed from
the upper surface of base wall 34.
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Disk 30 is disposed within closure shell 2~. 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 FIG. 4, each finger 50 is radially aligned with an
associated bead segment
49, which in turn is spaced from the opposed ends of adjacent bead segments 48
by a pair of gaps
51. Bead segments 49 preferably are of shorter circumferential dimension than
are fingers 50, so
that each finger 50 is also radially aligned with an associated pair of gaps
51. Each spring forger
50 extends upwardly from the upper surface of disk body 46, and then radially
outwardly in the form
of a rounded bead 52. In assembly, beads 52 of fingers 50 are received by snap
fit over shoulder 44
on shell base wall 34 to retain the disk in assembly with the shell. This
retention of the disk
preferably is a loose retention (before assembly to a container), allowing
disk 30 to rotate with
respect to the surrounding shell. The ends of the fingers and the beads
preferably are flush with or
beneath the upper surface of base wall 34 when the closure is secured to the
container finish, as best
seen in FIGS. 1 and 2.
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
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compression molded onto the disk employing an assembly fixture 60 such as that
illustrated in FIG.
11, and the disk/liner subassembly then assembled to the closure shell. As
another alternative, the
liner may be formed separately, such as by stamping from a sheet of liner
material, and then secured
to the undersurface of the disk by adhesive or other suitable means. Liner 32
may be of any suitable
material construction. In accordance with the preferred embodiments of the
invention, liner 32 is
of resin construction, and most preferably includes a barrier material to
resist permeation of gases,
water vapor and/or flavorants through the liner. The liner most preferably is
provided in accordance
with the disclosure of one of the U.S. Patents 6,371,318 and 6,399,170 noted
above, the disclosures
of which are incorporated herein by reference. Other suitable barrier liners
or non-barrier liners
alternatively may be employed. Closure shell 28 and disk 30 preferably are of
molded plastic
construction, such as polypropylene. Container 22 may be of glass or plastic
construction.
After container 22 has been filled with material, typically fluid material,
closure 26
is secured over the finzsh 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
I5 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 ftnish by a ring 56
that extends around the
outer periphery of disk body 46. Ring 56 has a wiper bead 58 (FIGS. 6 and 7)
that slidably engages
the outside edge container finish to align disk 30 and liner 32 with the edge
of the container ftnish.
Disposition of disk bead 48 around the periphery of the disk places the bead
in approximate axial
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alignment with the end of the container finish, so that compression of the
liner and the disk as the
closure is secured to the container does not tend to bend or distort the body
of the disk. After the
closlue is secured to the container, flushing fluid, such as air or water, may
be directed into opening
42 of closure base wall 34 and between disk fingers 50 into the area between
the upper surface of
disk body 46 and the lower surface of closure base wall 34. This flushing
fluid travels radially
outwardly through this area between the disk and the closure base wall,
through gaps 51 between
disk peripheral bead segments 48, 49, and then downwardly between the inside
surface of skirt 36
and the outside surface of finish 24. Disposition of fingers 50 in alignment
with gaps 51 between
bead segments 48, 49 (FIG. 4) ensures that the flushing fluid traverses the
entire area between the
disk and the closure base wall.
FIG. 8 illustrates a modified liner disk 30a in which, as compared with disk
30 in
FIG. 4, bead segments 49 are eliminated, and gaps S I a between opposed ends
of bead segments 48
are correspondingly enlarged. Liner disk 30 of FIG. 4 is preferred because
bead segments 49
provide support between the disk periphery and the underside of the closure
shell base wall against
I S forces applied to the disk by tightening of the closure onto a container
finish. FIG. 9 illustrates
anather modified liner disk 30b, in which bead segments 48, 49 of FIG. 4, or
bead segments 48 of
FIG. 8, are replaced by a circumferential array of angularly spaced nubs or
lugs 48b. This
circumferential array of nubs is disposed adjacent to the periphery of disk
body 46 to provide
support against the forces incurred as the closure is applied to the container
finish. FIG. 10
illustrates a modified closure assembly in which liner disk 30c terminates at
bead segments 48 - i.e.,
does not include ring 46 and wiper bead 48 of the embodiment in FIGS. 2 and 5-
6. Liner 32c
terminates at the periphery of disk 30c, and does not extend around the
radially outer edge of the
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container finish. FIG. 12 illustrates a modification to the embodiment of FIG.
10 in which disk 30d
and liner 32d are flat in the sealing area - i.e., the disk bead 54 (FIG. 2)
has been deleted.
FIG. 13 illuslxates a modifl.cation to the embodiment of FIG. 2, in which a
tamper
indicating band 62 is frangibly secured to the lower edge of closure skirt 36.
A circumferentially
continuous or segmented stop flange 64 extends from band 62 to engage a stop
bead 66 on container
finish 24. In an embodiment of the invention having a tamper indicating band
(FIGS. 13 and 14),
the dimensional relationships preferably are such that, when the closure is
unthreaded from the
container, the tamper indicating band is severed from the closure skirt before
the seal is broken at
the upper end of the container finish.
FIG. 14 illustrates a closure and container package 70 in accordance with
another
embodiment of the invention. A molded plastic container 72 has a finish 74
that terminates in a
flange 7C, which is a vestige of a trimming operation after molding. A closure
78 has a skirt 80 with
a tamper indicating band 82 connected thereto by frangible bridges. A disk 84
is secured to the base
wall 86 of closure 78 as previously described, and a liner 88 is mounted on
the underside of disk 84.
Liner 88 engages finish flange 76 to seal the package. As previously noted in
connection with FIG.
13, the dimensional relationships of the closure and container, and the
flexibility of flange 76,
preferably are such that tamper indicating band 82 is ruptured from skirt 80
before the seal is broken
at liner 88.
Container 22 (FIGS. 1-2, 10 and 12-13) may be of glass or plastic
construction.
Container 72 (FTG. 14) preferably is of blow molded plastic construction.
Closure shells 28 and 78,
disks 30, 30a, 30b, 30c, 30d, and 84 may be of any suitable plastic
construction, such as
polypropylene.
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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
I S modifications and variations as fall within the spirit and broad scope of
the appended claims.
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