Note: Descriptions are shown in the official language in which they were submitted.
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COMPOSITE CLOSURE WITH BARRIER END PANEL
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S.
Provisional Patent Application No. 60/580,946, filed June 18,
2004.
[0002] The present invention is directed to a composite
closure cap for containers such as, but not limited to, plastic
bottles and jars. The closure cap includes a disc-shaped end
panel that has excellent oxygen barrier properties. Application
of the closure cap results in a hermetic seal between the
container and the cap. More particularly, the present invention
is directed to a composite closure cap with an end panel made
substantially of plastic, having oxygen barrier properties and
providing a hermetic seal between the container and the cap in a
variety of sealing and sterilization environments.
BACKGROUND OF THE INVENTION
[0001] Composite closures are well known in the art.
Composite closures typically include two parts (thus, the word
"composite"), an annular shell or ring with a central opening
and a separate end panel covering the central opening.
Composite closures are often used in products that are either
hot filled or are thermally pasteurized or sterilized after
filling, including products where the entire package (filled
container with sealed closure) is subjected to "retorting"
(i.e., heating the package to a temperature greater than 220 F).
[0002] Most currently available composite closures include a
metal end panel and an annular gasket or ringed liner that
provides a hermetic seal between the closure and the container
finish. The metal end panel of the metal/plastic composite
closure provides a good barrier to oxygen which, if allowed to
freely permeate the package, can result in spoilage of the food
product. More recently, composite closures where the end panel
is made substantially of a non-metal material, such as plastic,
have been introduced. Such "all-plastic" composite closures
have the advantage of the end panel being less susceptible to
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corrosion and are less costly to manufacture.
[0003] Although, many of the known composite closures have
worked satisfactorily, there is a continuing need for composite
closures that (1) effectively limit the ingress of oxygen
through the closure, (2) seal the package to further limit
oxygen ingress at the interface of the container finish and
closure cap, (3) provide evidence of tampering, and (4) reduce
the cost of manufacture.
[0004] Whether the composite closure includes a metal or
plastic end panel, but particularly where the end panel is made
substantially of plastic, maintaining the integrity of the seal
can be particularly problematic in food products packaged in
plastic containers that are subjected to retorting. Plastic
containers and, more. particularly, the plastic container
finishes that are subjected to retort often undergo expansion
and subsequent contraction. The expansion and contraction of
the container finish affects the seal interface between the
container and the closure, thus making it more possible that the
product can spoil. Thus, there is a need for a closure with the
properties previously described that can also be subjected to
retort while maintaining the integrity of the seal. The closure
of the present invention addresses the above-stated needs.
BRIEF DESCRIPTION OF THE FIGURES
[0005] Fig. 1 is a perspective view of one embodiment of the
composite closure fitted onto a container finish;
[0006] Fig. 2 is a perspective view of the composite closure
of Fig. 1 with a section broken away to show the end panel disc
lined with a ring (gasket) of sealant;
[0007] Fig. 3 is a top view of a package with the closure
embodying the present invention;
[0008] Fig. 4 is a partial cross-sectional side view of the
composite closure of Fig. 3 taken along line 4-4;
[0009] Fig. 5 is a partial, cross-sectional side view of the
closure cap of Fig. 1 taken through a vent, with the closure
fitted onto a container finish;
[00010] Fig. 6 is a bottom view of the closure cap shell
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without the end panel disc;
[00011] Fig. 7 is a plan view of the closure cap of Fig. 1
fitted onto a container finish showing the internal threads and
bead on the closure inner surface and the threads on the outer
surface of the container neck (in broken lines);
[00012] Fig. 8 is a perspective view of an alternative
embodiment of the closure cap with a section broken away, with
the closure fitted onto a container finish;
[00013] Fig. 9 partial, cross-sectional side view taken along
9-9 of Fig. 8;
[00014] Fig. 10 is a partial, cross-sectional side view taken
along 10-10 of Fig. 8;
[00015] Fig. 11 is a cross-sectional view of the closure of
Fig. 1 after insertion of the end panel into the shell, but
prior to placement on a container finish; and
[00016] Fig. 12 is an enlarged cross-sectional view of the
closure cap of Fig. 1 fitted onto a container finish.
[00017] Fig. 13 is a perspective view of another embodiment of
the closure cap fitted onto a container finish, the closure cap
including an end panel with a mechanically shaped vacuum
activated button (in the up position);
[00018] Fig. 14 is a perspective view of the closure cap of
Fig. 13 with the vacuum activated button (in the down position);
[00019] Fig. 15 is a top view of the closure of Fig. 13;
[00020] Fig. 16. is a cross-sectional side view of the closure
of Fig. 13 taken along 15-15 of Fig. 15;
[00021] Fig. 17 is a cross-sectional side view of the closure
of Fig. 14 taken along line 16-16 of Fig. 15.
[00022] Fig. 18 is a partial perspective view of another
alternative embodiment of the composite closure.
[00023] Fig. 19 is a partial cross-sectional side view of the
closure cap of Fig. 18 taken along line 19-19, fitted onto a
container finish;
[00024] Fig. 20 is a partial cross-sectional side view of the
closure cap of Fig. 18 taken along line 20-20, fitted onto a
container finish;
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[00025] Fig. 21 is a perspective view of still another
alternative embodiment of the shell 9 of a composite closure;
[00026] Fig. 22 is a partial cross-sectional side view of the
closure cap of Fig. 21 taken along line 22-22, fitted onto a
container;
[00027] Fig. 23 is a partial cross-sectional side view of the
closure cap of Fig. 21 taken along line 23-23, fitted onto a
container;
[00028] Fig. 24 is a perspective view of still another
alternative embodiment of the closure cap with a portion broken
away;
[00029] Fig. 25 is a side view of the closure cap of Fig. 24
with a portion broken away;
[00030] Fig. 26 is a different (bottom) perspective view of
the closure cap of Fig. 24.
[00031] Fig. 27A is a cross-sectional side view of the closure
cap prior to insertion of the end panel into the shell;
[000321 Fig. 27B is a cross-sectional side view of the closure
cap with end panel inserted into the shell but prior to
application of the closure onto the finish of a container;
[00033] Fig. 27C is a cross-sectional side view of the closure
cap as it is being applied onto the finish of a container;
[00034] Fig. 27D is a cross-sectional side view of the closure
cap at a later stage during the application of the closure cap
onto the finish of a container;
[00035] Fig. 27E is a cross-sectional side view of the closure
cap at a still later stage during the application of the closure
cap onto the finish of a container as the finish 'fully engages
the closure.
[00036] Fig. 27F is a cross-sectional side view of the closure
cap at the final fully sealed position relative to the closure
finish;
[00037] Fig. 28 is a perspective view of the end panel with
the gasket applied to the lower panel surface;
[00038] Fig. 29 is a cross-sectional side view of a pre-formed
end panel with the gasket applied to the peripheral portion of
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the lower panel surface;
[00039] Fig. 30 is a cross-sectional side view of a flat end
panel with the gasket applied to the peripheral portion of the
lower panel surface;
[00040] Fig. 31 is a cross-sectional side view of the
preformed disk of Fig. 29 being applied to the shell of the
closure; and
[00041] Fig. 32 is a cross-sectional side view of the closure
of Fig. 31 applied to the finish of a container.
DESCRIPTION OF THE EMBODIMENTS
[00042] With reference to the Figures, closure cap 10 includes
a generally cylindrical shell 12 having a central opening
covered by an end panel 20 held within shell 12. Shell 12 is
preferably molded from a plastic material such as, but not
limited to, polypropylene.
[00043] As shown in the Figures and, in particular, Fig. 2,
shell 12 includes a downwardly extending skirt 14 integrally
formed with an upper radially and inwardly extending flange 18.
Flange includes a top surface 19 and a bottom surface 21. As
best seen in Figs. 4 and 5, top surface 19 of flange 18 is
slightly downwardly sloped in the direction of the closure
center.
[00044] As shown in Figs. 2, 8, 11 and 12, the inner
circumferential surface of skirt 14 is provided with one or more
preformed threads 22. Thread 22 is intended for cooperative
mating engagement with corresponding thread(s) 23 on the
container finish 27, as generally depicted in Fig. 7 and
elsewhere. In a preferred embodiment, thread 22 is a single
lead thread that extends more than 360 on the inner surface of
ring 12. Al,ternatively, thread 22 may also be a multi-lead
thread.
[00045] The inner circumferential surface of skirt 14
includes, preferably, lifting bead 24, which is located above
thread 22 and, more specifically, above the upper terminal end
of thread 22. Lifting bead 24 lifts end panel 20 and releases
it from its sealing contact with the container during the
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opening sequence. In a preferred embodiment, lifting bead 24 is
substantially horizontal (i.e., does not slope). In one
embodiment, bead 24 may extend around the entire circumference
of shell 12 (i.e., 3600). More preferably, bead 24 may extend
less than 360 around shell 12. In one embodiment, lifting bead
24 extends approximately 240 or less around ring 12 and is
continuous (i.e., uninterrupted). However, as shown in Fig. 26,
discussed below, lifting bead may also be non-continuous and be
made up of a series of annular bead segments 24a, 24b, etc.
[00046] Alternatively, shell 12 may be provided without
lifting bead 24. Where bead 24 is absent, release of disc 20
from the container may be achieved by the lifting action of one
of the threads 22. This provides for more distance between disc
20 and the lifting means (i.e., thread 22), thereby maximizing
the travel distance of disc 20 before the primary seal of the
package is broken. This may be advantageous where more
sequential opening is desired.
[00047] Attached to the terminal end of skirt 14 is a tamper
evident band 26. In a preferred embodiment, ~ band 26 may be an
extension of skirt 14 and be attached to skirt 14 by a plurality
of bridges, at a location below a container retaining bead 60.
A continuous or semi-continuous slit 28 or line of weakening
between skirt 14 and band 26 is also provided to allow for
separation of the cap from band 26 during opening. Band 26
further includes an upwardly and annular inwardly extending
retaining member 29 for engagement of bead 60 on the container
finish 27. An example of this type of tamper evident band is
disclosed in U.S. Patent No. 5,685,443, incorporated herein by
reference. Alternatively, band 26 may include a series of
annular ratchets or ratchet segments (not shown) that engage
corresponding ratchets 37 (see Figs. 19-20, 22-23) on the finish
27 of the container. Such ratchet engagement is well known and
will be understood by those of skill in the art.
[00048] In the embodiment of Fig. 11, end panel 20 has an
outside diameter that is less than the inside diameter of ring
12 at the inner surface of skirt 14 between lifting bead 24 and
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the transition portion 43 between skirt 14 and flange 18. In
the embodiment of Fig. 1, as best seen in Fig. 11, the outside
diameter of end panel 20 is slightly greater than the diameter
of lifting bead 24 which allows end panel 20 to rest flat on the
lifting bead 24 when closure 10 is in the assembled state but
prior to placement of the assembled closure on a container
finish. Thus, end panel 20 is free-floating between lifting
bead 24 and the bottom surface of flange 18.
[00049] End panel disc 20 may be made of any suitable plastic
composition and may be provided as a single sheet or layer or,
as described below, a plurality of sheets. In one embodiment,
end panel 20 may be made of one or more layers of polypropylene.
Preferably, however, the disc is made of a material(s) that has
good oxygen barrier properties. One example is a material that
includes a metal component, such as a metal film.
Alternatively, non-metallic, (e.g., plastic) substantially
oxygen impermeant compositions may also be used. In one
embodiment, where oxygen barrier properties are desired, end
panel disc 20 is made of a single layer of one or more plastic
materials, wherein at least one of the materials is an oxygen
barrier.
[00050] In another embodiment, end panel disc 20 may be a
multi-layered disc 20. A multi-layered disc, as shown, for
example, in Figs. 5 and elsewhere, can be made by a variety of
methods. In one embodiment, disc 20 can be made from co-
extruded sheets of multiple sheet.layers. In still another
embodiment, disc 20 can be made by molding, such as by injection
molding.
[00051] As shown in Fig. 5, for example, the multi-layered
disc may include top 32, middle 34 and bottom 36 sheets of a
plastic material, wherein at least one layer includes oxygen
barrier properties. In one embodiment, top layer 32 may be made
of a plastic material such as, but not limited to, a
polypropylene and/or polypropylene co-polymer. Middle layer 34
may be a compound with good oxygen barrier properties. For
example, middle layer 34 may be an ethylene vinyl compound such
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as, but not limited to, EVOH. Bottom layer 36 may be a
polypropylene or a polypropylene co-polymer. Additionally,
where disc 20 is a multi-layer disc 20, it may include adhesive
between the top and middle layers and between the bottom and
middle layers.
[00052] Alternatively, the material having the oxygen barrier
property (e.g., EVOH) may comprise top layer 32. Thus, in this
alternative embodiment, top layer 32 may be an oxygen barrier,
middle layer 24 may be a bonding layer and bottom layer 36 may
be polypropylene, a copolymer thereof or other polymeric
material with insubstantial oxygen barrier properties. Examples
of commercially available films that may be useful in the
manufacture of end panel 20 include Besela films available from
Kureha Chemicals.
[00053] In addition to or as a further alternative to the
above, disc 20 may include an oxygen scavenger. Preferably, the
scavenger will be combined, blended or otherwise incorporated
into a single-layer disc. Where disc 20 is made of multiple
layers, bottom layer 36 may include an oxygen scavenger so as to
reduce head space oxygen levels after sealing of the container.
Examples of suitable scavengers include fine sodium ascorbate
particulate or powder. Other examples of oxygen scavengers
include iron-based compounds, such as ferrous oxide. Using an
oxygen scavenger with one or more layers of an oxygen barrier
provides an active and passive barrier system.
[00054] Although the thickness of panel will depend, in part,
on the size of closure 10, in most of the embodiments described
herein a panel thickness of approximately 0.020 inch is
preferred. An end panel of reduced thickness may be preferred
for purposes of cost reduction and effective heat transfer,
particularly during a retort process. In the embodiment, where
the top and bottom layers are polypropylene or copolymers
thereof with a middle layer of, for example, EVOH in between,
the thickness of the middle layer will preferably be
approximately 1.2 mils.
[00055] Closure cap 10 may also include an annular gasket or
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liner 38 which is sealingly engageable with the end and
preferably inner surfaces of the container finish. Liner 38 may
be a full pad liner that substantially covers the entire bottom
surface of disc 20. Liner or gasket 38 may be applied to the
bottom of end panel disc 20. In a preferred embodiment, sealant
is provided as a ring or gasket 38 around the outer periphery of
disc 20, as best seen in Figs. 2, 4 and S. An example of a
gasket and its method of manufacture and application is provided
in U.S. Patent Application Serial No. 09/634,182, filed August
9, 2000, and U.S. Patent Application Publication No.
2003/0098287 Al, filed January 9, 2003, both of which are
incorporated herein by reference. Gasket 38 provides an
effective seal between end panel disc 20 and container finish
27. Gasket 38 is preferably injection molded onto end panel
disc 20. Suitable compositions for use in the gasket 38 or
liner 38 are any compositions that can provide a hermetic seal
with container finish 27. In one embodiment, the sealant may be
made of polypropylene or copolymer thereof. Other known sealant
compositions that may be used include a SEBS block copolymer.
Thermoplastic elastomers or other compositions which have oxygen
barrier properties to varying degrees may also be used. Such
thermoplastic elastomers are disclosed in U. S. Patent No.
6,677,397 and U.S. Patent Application Serial No. 10/400,304,
filed March 27, 2003, both of which are incorporated herein by
reference. Although any suitable TPE or TPE-based composition
may be used for gasket 38, the preferred plastic compositions
disclosed in Serial No. 10/400,304 are particularly useful in
the closures described herein.
[00056] Composite closures of the present invention provide
further improvement in oxygen barrier properties over more
traditional metal/plastic composite closures (i.e., plastic
fitment ring with metal end panel). In one study, the oxygen
barrier properties of (A) a composite closure including a
polypropylene/EVOH/polypropylene end panel 20, lined with a
gasket made of the preferred sealant composition described in
U.S. Serial No.10/400,304 was compared to (B) a metal/plastic
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composite closure lined with a plastisol composition.
[00057] Using an oxygen permeability measuring apparatus,
Model Ox-Tran2/61, available from MOCONo of Minneapolis,
Minnesota, closures of the present invention (as described
above) exhibited an oxygen ingress rate of typically less than
approximately 0.003 cc/package/day/atm, measured at 65% relative
humidity (and based on a 40 mm closure), and approximately
0.0025 cc/package/day/atm. Plastic/metal composite closures,
lined with plastisol exhibited an oxygen ingress rate of
approximately 0.0041 cc/package/day/atm. (Briefly, equipment of
the type described above measures oxygen ingress by introducing
nitrogen gas into a vessel sealed with a lined closure. The
nitrogen gas flushes any oxygen that may be present, due to
ingress through the closure, within the sealed vessel. The
nitrogen gas exits the vessel through an outlet and the level of
captured oxygen is recorded as an electronic signal and reported
as cubic centimeters (cc) of oxygen permeating into a package
(closure with liner) in a day. The reading is then adjusted to
take into account barrier properties of the container or vessel
to give a more accurate reading.
[00058] As shown in Figs. 1-2, closure cap 10 includes a
'plurality of annularly spaced vents 40 along the bottom surface
21 of flange 18. Vents 40 provide flow channels for draining
liquid (water) used to cool or rinse the package. Vents 40 may
be regularly spaced from each other and separated by portions of
flange 18 identified by reference numeral 42. When the
container is sealed by closure cap 10, portions 42 are in
contact with disc 20, as shown, for example, in Fig. 4.
[00059] The closure 10 of the present invention is
particularly well-suited for use in hot-fill or retort
environments, provided that the container is likewise suitable
for use in retort operations. Further alternative embodiments
of a "retortable" closure for use with more traditional
container materials are also described below.
[00060] Figs. 8-10 depict an alternative version of a closure
cap embodying the present invention. As in the above-described
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preferred embodiment, closure cap 10 includes a fitment ring 12
and an end panel disc 20 within ring 12. Whereas in the
previous embodiment (of Figs. 1-7) flange 18 of shell 12 defines
a central opening, in the embodiment of Figs. 8-10, ring 12
include a further central panel 50 overlying end panel disc 20.
[00061] Preferably, central panel 50 is integral with ring 12
and is made of the same (plastic) material as ring 12 during the
molding process. As shown n Fig. 8, central panel 50 is
attached to flange 18 by the areas 52 of connecting arms 52
radiating from central panel 50. The sides of connecting arms
52, the end wall 54 of central panel 50 and the end wall 43 of
flange define windows 56 through which disc 20 is exposed to the
outside environment. Preferably connecting arms 52 of the web
have a thickness that is about (1/2) of the thickness of flange
18. As in the previously described embodiment, ring 12 includes
a plurality of annularly spaced vents 40 along the bottom
surface of flange 18 separated by portions 42 of flange 18.
Vents 40 may be interrupted by connecting arms 52 of ring 12, as
best seen in Fig. 8.
[00062] In all other respects, closure cap 10, shown in Figs.
8-10, is substantially identical to the previously described
embodiments. Ring 12, such as the one shown in Figs. 8-10 and
described above may be used where a more robust'ring 12 is
desired, (as the central end panel 50 reinforces ring 12.)
Panel 50 also provides a surface that can be used for printing,
embossing or otherwise applying product information thereon.
[00063] Figures 13-17 depict another alternative embodiment or
feature of closure 10 and more specifically, end panel disc 20.
In the embodiments of Figs. 13-17, end panel disc 20 includes a
vacuum activated button. Composite closures with mechanically
formed buttons in the end panel are disclosed in U.S. Patent No.
4,989,740, which is incorporated herein by reference. In the
embodiment of Figs. 13-17, the at least substantially plastic
end panel disc 20 may be mechanically pre-formed to include a
vacuum-activated button. The presence of vacuum in a sealed
container is an indication that the container is sealed. A
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button in a down state can be detected in a filling line at high
speed rates using optical measurement sensors.
[00064] Figs. 18-32 depict additional embodiments of closure
cap 10 of the present invention. In many respects, the closure
cap 10 is similar or identical in structure and materials to
closure cap 10 previously described. Where such similar or
identical features are included in the embodiments of Figs. 18-
32, they will not be described in great detail and, instead, it
will be understood that the previous description of the similar
or identical feature is incorporated by reference. Thus, for
example, while the embodiments of Figs. 18-32 do not show tamper
evident bands attached to the terminal end of skirt 14, as
shown, for example, in Figs. 1-17, it ',vill be understood that
closures shown in Figs. 18-32 will include some tamper
indicating means. The tamper indicating band 26 may include a
retaining member 29, as shown in Figs. 1-17, and previously
described, or may include annular ratchets for engagement with.
the neck of container 33. 1
[00065] Not only do the closure caps 10 of Figs. 18-32 provide
the good barrier to oxygen and evidence of product tampering,
also provided by the previously described embodiment, but they
are also particularly well suited for retorting operations and
'effectively maintain the hermetic seal even after temperature
changes and the bottle expansion and contraction that is
encountered during retort.
One such example of a retortable closure is shown in Figs. 18-
21. As shown in Fig. 18, composite closure 10 includes shell 12
with end panel 20, as previously described. Shell 12 may
typically be made of polypropylene or other suitable plastic
materials. Shell 12 includes a downwardly extending skirt 14
that, as in the previously described embodiments, is integrally
formed with flange 18. Also, as described above, inner surface
of skirt 14 includes one or more threads for cooperative
engagement with the threads of the container 23, as seen in the
cross-sectional view of Fig. 19. Inner surface of skirt 14 of
the embodiments shown in Figs. 18-32 also includes bead 24, as
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generally described above. Bead 24 is located above the upper
terminal end of thread 22 on the inner surface of skirt 14, and
lifts end panel 20 during the opening sequence.
[00066] In one embodiment, shown in Fig. 26, bead 24 extends
360 around the inner surface of skirt 14 and is non-continuous.
For example, bead 26 may be provided as a series of annular bead
segments that extend 360 or less than 360 around the inner
surface of skirt 14 and are separated from one another.
Alternatively, bead 24 may be a continuous bead that extends
less than 360 and, preferably, 240 around the inner surface of
skirt 14, as previously described.
[00067] As in the previous embodiments, shell 12 of the
closure shown in Fig. 18 includes top flange 18 integrally
formed with skirt 14. Flange 18 includes a top surface 19, and
a bottom surface 21. Flange 18 of the closure shown in Fig. 18
differs, however, from the previously described embodiments in
that it has a generally C-shaped cross-section and/or profile,
as best seen in Fig. 19. More specifically, as shown in Figs.
19 and 20, both flange top surface 19 and bottom surface 21 have
a generally C-shaped profile where the top surface 19 and bottom
surface 21 parallel to one another. As shown in Fig. 19, bottom
surface 21 includes a radially inner, downwardly extending
portion 21a, a downwardly extending portion 21c, and a central
curved portion 21b. Similarly, flange top surface 19 may
include a radially inner downwardly extending portion 19a, a
radially outer, downwardly extending portion 19c, and a central
curved portion 19b, as shown variously in Figs. 18-26. In- one
embodiment, only the bottom surface may have a generally C-
shaped profile, while flange top surface 19 may include a
different profile. For example, flange top surface 19 may
include a generally C-shaped profile and provide a relatively
and continuously smooth surface (as shown, for example, in Figs.
24-26). Alternatively, flange top surface 19 may have something
other than a generally C-shaped profile and include, for
example, notch 29 between the top curved and radially outer
portions of flange top surface 19.
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[00068] Shell 12 of composite closure 10, shown in Figs. 18-
32, may also include a plurality of vents 70. Typically, vents
70 are annularly spaced from one another along the entire
circumference of shell 12. As shown in Figs. 18, 21, and 24,
for example; vents 70 open to the outside in flange 18 between
central curved portion 19b and downwardly extending radially
outer portion 19c of flange top surface 19. As shown in Fig.
19, vents 70 provide a flow path 72 between skirt 14 and the
finish 17 of the container 23.
[00069] As shown in Figs. 18-32, composite closure 10 also
includes end panel 20. End panel'20 of the embodiments shown in
Figs. 18-32 is substantially identical to end panel 20
previously described, particularly in terms of its material
composition. That is, in one embodiment, end panel 20,
preferably has oxygen barrier properties. Furthermore, as
previously described, end panel 20 may be made of a single layer
or sheet of one or more plastic materials or, is preferably made
of a plurality of sheets where one or more of the sheets
include(s) an oxygen barrier and/or an oxygen scavenger. As
previously described, in a preferred embodiment, end panel may
be made of three (3) layers or sheets, where the middle sheet
includes an oxygen barrier, such as EVOH, while top and bottom
sheets include polyptopylene or other suitable plastic material.
Adhesives may be used as,necessary, and as previously described.
Of course, where a multi-layer end panel is desired, such end
panel can be made by molding or extrusion, as previously
described.
[00070] As shown in the Figures, end panel 20 includes a top
surface 20a and a lower surface 20b. End panel 20 further
includes a central portion 60 and outer peripheral portion 62.
In a preferred embodiment, end panel 20 may be provided with a
liner (e.g., full pad) or gasket 38 of sealant, as previously
described and shown more particularly in Figs. 28-30.
Preferably, gasket 38 is applied as a ring on the lower surface
20b at least the peripheral portion of end panel 20, as shown in
Fig. 28. The method of manufacture and application of gasket 38
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to end panel 20 is beyond the scope of the present application.
However, methods of manufacture and application of gaskets are
described in U.S. Patent Publication No. 2003/0098287 Al, filed
January 9, 2003, and U.S. Patent Application Serial No.
09/634,182, filed August 9, 2000, both of which have been
previously incorporated by reference.
[00071] End panel 20 may be provided as a flat disc, as shown
in Fig. 30. During application of closure 10 to container
finish 27, disc 20 is substantially conformed to the flange
bottom surface 21. Alternatively, end panel 20 may be provided
as a contoured disc, as shown in Fig. 29, that is preformed to
substantially conform to the profile of flange bottom surface
21. When provided as a flat disc, the overall diameter of disc
20 may be greater than the diameter of the skirt inner surface.
[00072] Figs. 27A-27F show the steps in the assembly of the
composite closure 10 and in the application of the assembled
closure 10 to a container finish 27. During assembly, end panel
20 is introduced through the mouth of shell 12. The end panel
20 is pushed through shell 12 to a point beyond bead 24 in
proximity to flange 18. Because of its greater diameter, end
panel 20 may bend slightly at outer peripheral portion 62 and
adopt a shape generally shown in Fig. 27b.
[00073] Fig. 27c shows the first step in the application of
closure 10 to container finish 27. As shown in Fig. 27c, the
end of the container finish first contacts outer peripheral
portion 62 of disc 20 and gasket 38 at the radially inner most
point thereof. Stated differently, contact by the container
finish 17 to the gasket 38 proceeds from radially inner part of
gasket 38 to radially outer part of gasket 38 or, as depicted in
Fig. 27, from the bottom up.
[00074] As contact between container finish 27 and end panel
20 continues during the application process, outer peripheral
portion 62 conforms to the shape of the flange bottom surface
21, as shown in Fig. 27d. In that regard, it is preferable that
disc 20 be provided with a point of weakening between central
portion 60 and outer peripheral portion 62. The point of
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16
weakening allows the plastic disc to bend at a point between
central portion 60 and outer peripheral portion 62, thereby
allowing end panel to bend and conform in the manner described
above and shown in Figs. 27a-27d. The point of weakening can be
provided as an area where the thickness of end panel disc has
been reduced during, for example, coining or cold-forming end
panel 20 to provide a notch 64 in disc 20.
[00075] Fig. 27e shows the outer peripheral portion of disc 20
conformed to the inner radial and central portions 21a and 21b
of flange bottom surface 21. As closure 10 is further advanced
onto the finish 27 of container 23, gasket 38 is compressed over
the inner and top surfaces of finish 27, thereby providing a
tight seal, as shown in Fig. 27f. The seal may become even
tighter after the expansion and, more importantly, contraction
of container finish 17 that typically occurs du-ring retort
operations.
[00076] Fig. 29 shows an alternative embodiment of end panel
20. In Fig. 29, end panel 20 is not presented as a flat disc.
Instead, end panel 20 is initially flat, but then shaped prior
to its introduction and association with shell 12. End panel 20
is contoured to more closely follow the shape of flange bottom
surface 21 at the inner radial and central portions 21a, 21b
thereof. Thus, end panel 20 may be shaped by, for example,
bending and contouring end panel in the present of heat, i.e.,
thermo-forming. Alternatively, shaped end panel may be provided
by injection or compression molding. As shown in Fig. 29, a
shaped, preformed end panel includes a generally planar central
portion 60. Near the outer peripheral portion 62 of end panel
20, disc slopes slightly downwardly (in the radially outward
direction) before becoming substantially planar again. In the
outer peripheral portion 62, disc 20 slopes upwardly (in the
radially outward direction), as shown in Fig. 29.
[00077] Whether end panel 20 is applied as a flat disc, as
shown in Figs. 27a through 27f, or applied as a preformed and
end panel, as shown in Figs. 31 and 32, composite closure 10 of
the present invention provides suitable sealing to the container
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-17-
finish 17. Unlike other retortable composite closures which
often require both radially inner and radially outer sealing of
the container finish, composite closure 10 of the present
invention, as shown in Figs. 18-32, primarily provides an'inner
and top seal. An effective seal is maintained to the container,
even after subjecting the package to the elevated temperatures
of retort.
[00078] As shown in Fig. 21, the composite closure may also be
provided with an additional central panel 50, as previously
described. Central panel 50 may be integrally formed with shell
12 during the molding process. Central panel 50 includes a web
of connecting members 52 annularly spaced from one another,
thereby exposing at least a portion of the end panel 20 to the
outside environment.
[00079] Figs. 22 and 23 are cross-sectional views of the
embodiment of Fig. 21 taken through a vent portion and a solid
portion of the shell 12, respectively. As seen in Figs. 22 and
23, central panel 50 may be spaced from end panel 20.
Alternatively, central panel 50 may contact top surface 20a of
end panel 20. As described above, central panel 50 provides
additional strength to shell 12. It also provides a surface
that may be embossed with a product name or include a stenciled
product name on the central portion of the central panel 50,
thereby further exposing the end panel 20 to the outside
environment. In all other respects, the contour of the flange
top and bottom surfaces is identical to the corresponding
surfaces described in relation to the embodiments of Figs. 18
and 24.
[00080] While the present invention has been described in
connection with various embodiments, it will be apparent to
those skilled in this art that modifications and variations may
be made therefrom without departing from the spirit and scope of
this invention. Accordingly, this invention is to be construed
and limited only by the scope of the appended claims.
