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Sommaire du brevet 2662268 

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Disponibilité de l'Abrégé et des Revendications

L'apparition de différences dans le texte et l'image des Revendications et de l'Abrégé dépend du moment auquel le document est publié. Les textes des Revendications et de l'Abrégé sont affichés :

  • lorsque la demande peut être examinée par le public;
  • lorsque le brevet est émis (délivrance).
(12) Demande de brevet: (11) CA 2662268
(54) Titre français: JOINT DE RECIPIENT A LANGUETTE ET PROCEDE DE FABRICATION
(54) Titre anglais: TABBED CONTAINER SEAL AND METHOD OF MANUFACTURE
Statut: Morte
Données bibliographiques
(51) Classification internationale des brevets (CIB):
  • B65D 55/02 (2006.01)
  • B32B 15/08 (2006.01)
  • B32B 37/00 (2006.01)
  • B65D 39/00 (2006.01)
(72) Inventeurs :
  • YOUSIF, PAUL E. (Etats-Unis d'Amérique)
(73) Titulaires :
  • TECH-SEAL PRODUCTS, INC. (Etats-Unis d'Amérique)
(71) Demandeurs :
  • TECH-SEAL PRODUCTS, INC. (Etats-Unis d'Amérique)
(74) Agent: RIDOUT & MAYBEE LLP
(74) Co-agent:
(45) Délivré:
(86) Date de dépôt PCT: 2007-09-20
(87) Mise à la disponibilité du public: 2008-04-03
Licence disponible: S.O.
(25) Langue des documents déposés: Anglais

Traité de coopération en matière de brevets (PCT): Oui
(86) Numéro de la demande PCT: PCT/US2007/020387
(87) Numéro de publication internationale PCT: WO2008/039350
(85) Entrée nationale: 2009-03-02

(30) Données de priorité de la demande:
Numéro de la demande Pays / territoire Date
11/527,668 Etats-Unis d'Amérique 2006-09-25

Abrégés

Abrégé français

L'invention concerne un joint de récipient amélioré comprenant au moins un élément de languette sans métal. Ce joint de récipient comprend une feuille de protection flexible sans métal et une feuille d'étanchéité flexible. La feuille de protection comprend au moins une couche de matériau en feuille flexible et inclut une partie de corps dont la dimension et la forme peuvent recouvrir au moins une finition de récipient, et comprend au moins une partie formant languette sans métal s'étendant depuis la périphérie de la partie de corps. La feuille d'étanchéité flexible comprend une couche de surface d'étanchéité thermoplastique, une couche de surface interne et une couche de film métallique. La feuille d'étanchéité flexible est de la même dimension et de la même forme que la partie de corps de la feuille de protection. La surface interne de la feuille d'étanchéité et la surface interne de la partie de corps de la feuille de protection sont collées ensemble en contact congruent opposé l'une avec l'autre. L'invention concerne également un procédé de fabrication de joint de récipient.


Abrégé anglais

An improved container seal including at least one metal-free tab member is provided. The container seal comprises a flexible, metal-free cover sheet and a flexible sealant sheet. The cover sheet comprises at least one layer of a flexible sheet material and includes a body portion that is sized and shaped to at least cover a container finish and has at least one metal-free tab portion extending from the periphery of the body portion. The flexible sealant sheet comprises a thermoplastic sealing surface layer, an inner surface layer and a layer of metal foil. The flexible sealant sheet is of the same size and shape as the body portion of the cover sheet. The inner surface of the sealant sheet and the inner surface of the body portion of the cover sheet are bonded together in opposed, congruent contact with each other.

Revendications

Note : Les revendications sont présentées dans la langue officielle dans laquelle elles ont été soumises.



-28-

I CLAIM:
1. A tabbed container seal comprising:
(a) a flexible, metal-free cover sheet having an outer surface and an
inner surface and comprising at least one layer of a flexible sheet material,
the cover
sheet including a body portion and at least one metal-free tab portion
extending
from the periphery of the body portion, the body portion being sized and
shaped to
at least cover a container finish,; and
(b) a flexible sealant sheet having an inner surface and a sealing
surface and comprising a thermoplastic sealing surface layer and a layer of
metal
foil, the flexible sealant sheet being of the same size and shape as the body
portion
of the cover sheet;
the inner surface of the sealant sheet and the inner surface of the
body portion of the cover sheet being bonded together in opposed, congruent
contact with each other.
2. The container seal of claim 1 wherein the sealant sheet
includes a polymeric barrier layer at the inner surface thereof.
3. The container seal of claim 2 wherein the polymeric barrier
layer is selected from the group consisting of an oxygen barrier film, a
moisture
barrier film, a solvent barrier film, and a combination thereof.
4. The container seal of claim 1 wherein the layer of metal foil
is bonded between the thermoplastic sealing surface layer and a polymeric
film.
5. The container seal of claim 1 wherein the inner surface of the
sealant sheet is the layer of metal foil.
6. The container seal of claim 5 further comprising a polymeric
barrier layer bonded between the layer of metal foil and the thermoplastic
sealing
surface layer.
7. The container seal of claim 6 wherein the polymeric barrier
layer is selected from the group consisting of an oxygen barrier film, a
moisture
barrier film, a solvent barrier film, and a combination thereof.


-29-

8. The container seal of claim 1 wherein the cover sheet
comprises a polymeric film, a polymeric foam, or a combination thereof.
9. The container seal of claim 1 wherein the cover sheet is a
multilayer laminate and the inner surface thereof comprises a layer of
polymeric
material.
10. The container seal of claim 9 wherein the outer surface of the
cover sheet comprises layer of paper or synthetic fabric.
11. The container seal of claim 1 wherein the outer surface of the
cover sheet comprises a layer of paper or synthetic fabric.
12. The container seal of claim 1 wherein the inner surface of the
cover sheet is directly bonded to the inner surface of the sealant sheet.
13. The container seal of claim 1 wherein the inner surface of the
cover sheet is bonded to the inner surface of the sealant sheet by a layer of
adhesive.
14. The container seal of claim 1 wherein the cover sheet
includes two opposed tab members extending from the periphery of the body
portion.
15. A method of manufacturing a tabbed container seal
comprising:
(a) bonding a first moving web of at least one band of a metal-
containing sealant sheet material to a second moving web of metal-free cover
sheet
material to form a moving composite web, the at least one band of metal-
containing
sealant material being narrower than the second web of metal-free cover sheet
material, and positioned relative to the second moving web so as to form a
band of
metal-containing sealing material comprising the sealant sheet material bonded
to
the cover sheet material, and at least one metal-free strip of cover sheet
material
adjacent thereto; and
(b) cutting a tabbed a container seal from the composite web in a
manner such that a tab portion of the container seal is formed from the at
least one
metal-free strip of cover sheet material and the remainder of the container
seal is
formed from the band of metal-containing sealing material.


-30-

16. The method of claim 15 wherein the at least one band of
sealant sheet material is positioned relative to the second moving web of
cover
sheet material so as to form a metal-free strip of cover sheet material on
both sides
of the band of metal-containing sealing material.
17. The method of claim 16 wherein the tabbed container seal
comprises two opposed tabs, each tab being formed from a metal-free strip of
cover
sheet material on opposite sides of the band of metal-containing sealing
material.
18. The method of claim 15 wherein the first moving web
comprises at least two bands of metal containing sealing sheet material
separated
from one another a strip of uncovered cover sheet material.
19. A composite web of container sealing material formed by the
process of claim 15.
20. A sealed container comprising:
(a) a container portion including an access opening and a rim
surrounding the access opening; and
(b) a container seal of claim 1 sized and shaped to fit over the rim of
the access opening, a peripheral portion of the sealing surface of the
container seal
being bound to the rim, and the metal-free tab portion of the container seal
being
freely graspable for removing the seal from the container.

Description

Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.



CA 02662268 2009-03-02
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TABBED CONTAINER SEAL AND METHOD OF MANUFACTURE
FIELD OF THE INVENTION
The invention relates to improved container sealing materials and
methods of manufacture thereof. More particularly, the invention relates to
improved container seals having a tab portion, and methods of manufacturing
the
tabbed container seals.
BACKGROUND OF THE INVENTION
It is common practice to seal a container with a sheet material, such
as paper, a polymeric film, aluminum foil, or a laminate of paper, polymeric
film
and/or aluminum foil. The use of such seals, in many cases, has been imposed
on
the packaging industry by FDA regulations, as a protection against product
tampering. Such seals can provide evidence of product tampering, since they
are
typically destroyed by the process of removing the seal. It is also common to
line
the inner surface of container closures with a moderately compressible
material,
such as a polymeric material, pulp board, or a multilayer laminated
combination
thereof. When a closure containing the liner material is secured to the finish
of a
container, such as by applying a torque force to a threaded closure that is
engaged
with a threaded container finish, the resulting pressure exerted by the
closure onto
the liner, which is interposed between the closure and the container finish,
produces
a substantially liquid and/or gas-tight seal. When the closure is removed from
the
container, the liner remains within the closure. Re-engaging the closure with
the
container finish reestablishes the seal. Liner materials can utilize a pulp or
paper
substrate, polymeric materials, such as polyolefin foams, laminated
znultilayer.
lining materials comprising a combination of pulp and/or a polymeric foam
along
with a polymeric film, metal foil, and the like.
In a typical application, closures for containers are lined with a
laminated material having a layer of pulp mounted to a layer of aluminum foil
by an
intermediate wax layer. Such laminated materials also frequently contain a
layer of
polymer, such as a polyester film, fixed by an adhesive to the foil, and a
layer of
heat-sealable polymer fixed by an adhesive to the polyester film. The laminate
is


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produced and shipped in roll form, which is then cut to the required shape and
size,
and mounted in a closure with an adhesive or by friction.
In use, the resulting lined closure is torqued onto a container, such as
a bottle or jar, which has been filled with a fluid or solid product. Next,
the capped
container is passed through a high frequency induction heating unit. During
induction heating, radio frequency energy heats the aluminum foil to a
temperature
in excess of about 65 C, generally about 150 C or greater. The resulting
heat
melts the wax in the layer between the pulp and aluminum foil. The melted wax
is
absorbed by the pulp, causing the pulp to separate from the remainder of the
material. The sealing material typically is a thermoplastic material selected
to
match the material of construction of the container, and is heat-welded (i.e.,
heat-
sealed) to the finish of the container (i.e., the rim around the access
opening of the
container) utilizing the heat.generated from the induction heating of the
aluminum
foil. Alternatively, the seal can be affixed over the access opening of a
container by
an adhesive, in which case the sealing material need not be a heat-sealable
thermoplastic polymer, and the container is sealed without recourse to
induction
heating. When a consumer removes the closure from the container, the pulp
layer
remains in the closure as a liner, leaving the laminated combination of foil,
polymer
film, and sealing material over the access opening of the container as seal,
to
provide evidence of tampering and/or to prevent leakage and contamination of
the
container contents during storage and shipment. To access the contents of the
container, the consumer must pierce the seal to remove it from the container.
Other conventional container seals have a die-cut tab extending
beyond the limits of the container finish, so that a consumer can grasp the
tab and
pull the seal off of the container. When a closure is included over the seal,
the tab
typically is folded over the side of the container finish, between the threads
of the
closure and of the container finish. When such tabs are induction sealable,
they
include a metal foil layer and have a heat-sealable polymer layer on their
underside.
During the induction sealing process the tab can become sealed to the threaded
side
of the container finish, which is generally undesirable. Alternatively, such
tabs can
be folded up over the seal so that the tab is sandwiched between the closure
and the


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seal. In this arrangement, the tab can become sealed to the closure, which is
also
undesirable. In addition, the shape of the tab can adversely influence the
induction
sealing of the seal to a container finish. For example, Wllliam Zito, in the
article
entitled "Does Frequency Matter? Comparing Efficiency of Induction Sealers" in
Food and Drug Packaging, 1986, reports that the bond between the container
finish
and the seal is generally weaker in the area where the tab is present relative
to the
seal along the remainder of the finish. The variability in bonding strength of
the
seal around the container finish can lead to leakage problems at the weaker
point
near the tab. An example of a die-cut tabbed container seal is described in
U.S.
Patent No. 4,778,698 to Ou-Yang.
Other container seals include a tab element constructed from one or
more folds in one of the layers of the laminated seal. Such folded-tab or" z-
tab"
structures are produced by laminating a sheet material having pleats or folds
onto a
flat sheet of material, so that the folded portion can act as a tab when a
container
seal is cut from the material in register with the folds. The folded portion
of the
seal is considerably thicker than the remainder of the seal, leading to uneven
pressure on the seal at the container finish (i.e., higher pressure at the
folds and
lower pressure at the unfolded portions). This can lead to uneven bonding and
possible seal failure. More even seals can be obtained when the folded layer
is kept
as thin as possible, however thin folds have a tendency to tear away from the
seal
upon removal. An example of such a folded tab seal is described in U.S. Patent
No.
4,934,544 to Han. Folded tab structures are complicated to manufacture and
have
not been readily accepted in the marketplace.
The tabbed container seals of the present invention overcome the
deficiencies of the conventional tabbed seals by providing a container seal
having a
tab portion that does not include a metal foil. The seals of the present
invention
provide for a uniform bonding strength between the seal and a container finish
during an induction sealing process.
SUMMARY OF THE INVENTION
The present invention provides an improved container seal including
at least one metal-free tab member. The container seal comprises a flexible,
metal-


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free cover sheet and a flexible sealant sheet. The cover sheet comprises at
least one
layer of a flexible sheet material and includes a body portion that is sized
and
shaped to at least cover a container finish and has at least one metal-free
tab portion
extending from the periphery of the body portion. The flexible sealant sheet
comprises a thermoplastic sealing surface layer and a layer of metal foil. The
flexible sealant sheet is of the same shape and size as the body portion of
the cover
sheet. The inner surface of the sealant sheet and the inner surface of the
body
portion of the cover sheet are bonded together in opposed, congruent contact
with
each other.
In some preferred embodiments the inner surface of the sealant sheet
comprises a polymeric barrier layer and the layer of metal foil is bonded
between
the thermoplastic sealing surface layer and the polymeric barrier layer. In
other
preferred embodiments the inner surface of the sealant sheet is the layer of
metal
foil. A polymeric barrier layer can be bonded between the metal foil and the
thermoplastic sealing surface layer, if desired. The polymeric barrier layer
can be,
for example, an oxygen barrier film, a moisture barrier film, a solvent
barrier film,
or a combination thereof.
The cover sheet can comprise a single layer of material or can be a
multilayer structure. The cover sheet can comprise a polymeric film or
coating, a
polymeric foam, a layer of paper, a layer of synthetic fabric, or a
combination
thereof. The polymeric film or coating can be a polymeric barrier such as an
oxygen barrier, a moisture barrier, a solvent barrier, or a combination
thereof.
The inner surface of the cover sheet can be directly bonded to the
inner surface of the sealant sheet or can be bonded to the inner surface of
the sealant
sheet by a layer of adhesive.
In some embodiments, the cover sheet includes a single tab portion,
while in other embodiments the cover sheet includes two opposed tab members
extending from the periphery of the body portion.
In use, a tabbed container seal of the invention is sealed over the
access opening of a container by thennally sealing (i.e., by conduction or
induction)
the sealing surface layer of the sealant sheet onto the container finish
(i.e., onto the


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rim surrounding the access opening) to seal the opening. The tab member, being
metal-free, does not interfere with the thermal sealing process and does not
adhere
to any portion of the container finish or to the top of the seal after the
container seal
has been bonded to the container finish. The tab portion is freely accessible
so that
a consumer can readily grasp the tab and pull the seal off of the container
opening
to access the contents of the container. The container seals of the present
invention
provide-a seal that is simple to manufacture, and which provides a more
reliable and
consistent seal than conventional tabbed induction seals.
The present invention also provides a method of manufacturing the
tabbed container seals of the invention. The method comprises bonding a first
moving web of at least one band of a metal-containing sealant sheet material
to a
second moving web of metal-free cover sheet material to form a moving
composite
web. The at least one band of metal-containing sealant sheet material is
narrower
than the second web of metal-free cover sheet material and is positioned
relative to
the second moving web so as to form a metal-containing band comprising the
sealant sheet material bonded- to the cover sheet material, with at least one
metal-
free strip of cover sheet material adjacent thereto. A tabbed container seal
is then
cut from the composite web in a manner such that a tab portion of the
container seal
is formed from the at least one metal-free strip of cover sheet material and
the
remainder of the container seal is formed from the metal-containing band.
ERIEF DESCRIPTION OF THE DRAWINGS
In the Drawings, Figure 1, Panel A shows the induction heating
pattern of a conventional container seal 10a having extended tabs, while Panel
B
shows the induction heating pattern of conventional container seal lOb having
tabs
folded over the top of the seal.
Figure 2, Panel A shows the induction heating pattern of a container
seal 12 of the invention having extended tabs, while Panel B shows the
induction
heating pattern of container seal 12 having its tabs folded over the top of
the seal.
Figure 3 shows a cross-sectional view of a conventional multilayer
container seal 14 bound to a container finish.


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Figure 4 shows a cross-sectional view of a multilayer container seal
16 of the invention bound to a container finish.
Figure 5 is a plan view of container sea120 of the invention.
Figure 6 is a plan view of container seal 22 of the invention.
Figure 7 is a plan view of container seal 24 of the invention.
Figure 8 is a plan view of container seal 26 of the invention.
Figure 9 is a plan view of container seal 28 of the invention.
Figure 10 is a plan view of container sea130 of the invention.
Figure 11 is a plan view of container seal 32 of the invention.
Figure 12 is a plan view of container seal 34 of the invention.
Figure 13 is a plan view of container sea136 of the invention.
Figure 14 is a plan view of container seal 38 of the invention.
Figure 15 is a cross-sectional view of container seal 40 of the
invention.
Figure 16 is a cross-sectional view of container seal 42 of the
invention.
Figure 17 is a cross-sectional view of container sea144 of the
invention.
Figure 18 is a cross-sectional view of container seal 46 of the
invention.
Figure 19 is a cross-sectional view of container seal 48 of the
invention.
Figure 20 is a cross-sectional view of container seal 50 of the
invention.
Figure 21 is a plan view of a composite web for manufacturing a
container seal of the invention.
Figure 22 is a plan view of a composite web for manufacturing a
container seal of the invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
As used herein and in the appended claims, the term "closure" and
grammatical variations thereof, refers to a lid or cap, such as a threaded
cap, a lug-


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type cap, a snap-cap, and the like, that is designed to be repeatedly secured
to and
removed from a container finish, such that when the cap or lid is secured to
the
container finish, a seal is formed that protects the contents of the container
from
contamination and leakage.
The terms "lining material" and "liner" refer to a sheet material that
is compressible and preferably semirigid, and is suitable for use within a
closure to
provide a resealable seal between the closure and a container finish. The term
"liner" also refers to a section of lining material that has been cut to fit
snugly
within a closure against the upper inside surface thereof.
The term "seal", when used as a noun, refers to a film or multilayer
laminate material that is adhesively secured or heat-sealed over the finish of
a
container to provide an air and/or fluid tight seal. To access the contents of
the
container, the seal must be broken. A seal can provide evidence of product
tampering, for example, when removal of the seal leaves a residue on the
finish of
the container. A container typically is fitted with a closure over a container
seal.
The closure protects the integrity of the seal during shipping and storage.
Closures
may include a liner, so that after the container seal is removed, the closure
can be
put back on the container to protect the contents that may remain in the
container.
When used as a verb, the term "seal" and grammatical variations thereof,
refers to a
process of covering the access opening of a container (e.g., ajar) with a
sheet of
flexible material bonded to the finish of the container.
The term "wax", as used herein, is not limited to natural waxes and
paraffins, but also encompasses materials commonly referred to as waxes in the
packaging and converting industries, such as microcrystalline wax,
polyethylene
wax, polyisobutylene resins, and so-called synthetic waxes (e.g., amide
waxes), as
well as mixtures thereof.
As used herein, the term "thermoplastic" refers to a flexible
polymeric material that reversibly softens and flows upon application of heat
and
pressure to the material. Two thermoplastic materials in contact with one
another
can be directly bonded together without the use of an adhesive by application
of
heat and pressure to the two materials.


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The term "directly bonded" and grammatical variations thereof, as
used herein and in the appended claims refers to a physical or chemical bond
between two sheet materials, which is achieved without the use of an adhesive.
For
example, a coating of one polymeric material onto a polymeric film web is a
directly bonded laminate.
As used herein as a noun, the term "laminate" refers to a composite
sheet material comprising at least two layers of individual sheets, films or
coatings.
The layers can be adhesively secured to one another, directly bonded to one
another,
or can be secured to one another by any combination of adhesive and direct
bonding. When used as a verb, the term "laminate" and grammatical variations
thereof, refers to the process of bonding sheet materials together in a stack
(i.e.,
lamination).
For convenience, the term "sheet material" and grammatical
variations thereof, is used herein to refer to any flexible material, which
has a
thickness that is substantially smaller in comparison to its length and
breadth, and
encompasses multilayer materials, as well as individual layers of sheets,
films,
coatings, foils, and the like, regardless of their thickness, and regardless
of whether
the layer was formed in situ by a coating process or was a preformed sheet or
film.
A container seal of the invention includes at least one metal-free tab
member. The container seal comprises a flexible, metal-free cover sheet and a
flexible sealant sheet. The cover sheet comprises at least one layer of a
flexible
sheet material and includes a body portion that is sized and shaped to at
least cover
a container finish and has at least one metal-free tab portion extending from
the
periphery of the body portion. In some preferred embodiments, the cover sheet
includes two opposed tab portions extending from the periphery of the body
portion. The flexible sealant sheet comprises a thermoplastic sealing surface
layer,
an inner surface and a layer of metal foil. The inner surface can be a
polymeric
fiim, such as a barrier film, or can be the layer of metal foil. The flexible
sealant
sheet is of the same shape and size as the body portion of the cover sheet.
The inner
surface of the sealant sheet and the inner surface of the body portion of the
cover


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sheet are bonded together in opposed, congruent contact with each other, while
the
tab portion of the cover sheet remains free and unbonded.
Optionally, a compressible sheet of lining material of the same size
and shape as the body portion of the cover sheet can be tacked to the outer
surface
of the cover sheet by a layer of releasable adhesive, such as a layer of wax
or like
expedient. The resulting integrated liner and container seal can be utilized
to seal a
container and line a closure for the container, as well.
In use, the sealing surface of the container seal is bound to the finish
of a container over the access opening of the container. The tab portion is
freely
graspable and not bound to the container finish. A consumer can grasp the tab
and
pull the container seal off of the container to access the contents sealed
therein.
In another aspect, the present invention provides a method of
manufacturing a tabbed container seal. The method comprises bonding a first
moving web of at least one band of metal-containing sealant sheet material to
a
surface of a second moving web of metal-free cover sheet material to form a
moving web of composite material. The sealant sheet material comprises a
thermoplastic surface layer, a layer of metal foil, and an inner surface. The
inner
surface of the sheet material is bound to a surface of the second web of cover
sheet
material directly or by means of an adhesive layer. The cover sheet material
is
metal-free and comprises at least one layer of a flexible material such as a
polymeric film, a synthetic fabric, or similar material. The at least one band
of
metal-containing sealant sheet material is narrower than the second web and is
positioned relative to the second moving web so as to form a band of metal-
containing sealing material comprising the sealant sheet bonded to the cover
sheet,
leaving at least one exposed metal-free strip of cover sheet material adjacent
to the
metal-containing band. A tabbed container seal is then cut from the composite
web
in a manner such that a tab portion of the container seal is formed from the
at least
one metal-free strip and the remainder of the container seal is formed from
the
metal-containing band portion of the composite web.
The sealant sheet, the cover sheet, and the liner, if present, can each
independently comprise one or more layers of material, such as cellulose pulp,


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paper, a synthetic fabric, a polymer film, a polymer foam, and the like, or
any
combination thereof, the layers being stacked and bound together to form a
laminate
material. The sealant sheet includes a layer of metal foil, such as aluminum
foil.
The sealing surface of the sealant sheet preferably comprises a thermoplastic
polymer film or coating (collectively referred to herein as a "thermoplastic
polymer
layer") for heat-bonding to a container finish.
A sealed container of the present invention comprises a container
having an access opening surrounded by a container finish. The sealed
container
includes a container seal of the invention bonded over its access opening. The
sealing surface of the container seal is bound to the finish over the access
opening
of the container along the periphery of the sealing surface of the container
seal. The
metal-free tab portion of the container seal is not bound to the finish of the
container and provides a mechanism for removing the seal from the container.
In one embodiment, the sealed container also comprises a closure
secured to the container finish over the cover sheet of the container seal.
Preferably, the closure includes a liner in contact with the cover sheet. The
liner
can be adhesively secured within the closure, if desired. In some embodiments
the
liner is tacked to the outer surface of the cover sheet by a layer of
releasable
adhesive. When a consumer removes the closure from the container, the liner,
which is secured within the closure, shears away from the tab sheet, breaking
the
adhesive bond between the liner and the cover sheet. The cover sheet remains
intact and bound to the sealant sheet. The consumer can then remove the seal
from
the container by grasping the tab portion and pulling the seal away from the
container finish. In some embodiments, a visible residue or portion of the
sealing
sheet remains bound to the rim of the container finish providing an indication
that a
seal was once bound over the access opening, for example as evidence of
tampering
(i.e., if the seal is removed prior to purchase of the container by the
consumer). The
liner and container seal can be applied to the sealed container as a single
integrated
unit by tacking the liner to the tab sheet of the container seal, if desired.
Typically, a container seal has peripheral dimensions slightly larger
than the peripheral dimensions of the container rim (finish). It is desirable
for


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inducti.on-heated container seals to seal evenly around the entire finish.
Induction
heating of a metallic layer in a container seal tends to result in the highest
temperature region being located around the periphery of the sealing surface
of the
container seal. When the seal includes metal-containing tabs, as in
conventional
container seals, the higher temperature periphery does not strictly follow the
shape
of the container finish. This can lead to sealing problems.
The following examples, depicted in the drawings, are provided to
further illustrate preferred embodiments of the present invention. The
embodiments
shown in the drawings, and the descriptions thereof, and are not to be
interpreted as
limiting the scope of the present invention.
Referring now to the drawings, wherein similar reference-numbers
refer to correspondingly similar components, Figure 1, Panel A schematically
illustrates a conventional tabbed container seal l0a including a metal-
containing tab
102a. Conventional container seal l0a is inductively heat-sealed over a
container
finish 104a (dotted lines). Shaded area 106a along the periphery of seal l0a
indicates a high temperature zone where the induction heating is most
concentrated.
High temperature zone 106a corresponds to the area where the most effective
bonding of seal 10a to finish 104a can occur. As can be seen in the drawing,
high
temperature zone 106a is located away from finish 104a in region 108a adjacent
to
tab 102a. This can lead to inefficient bonding and even seal failure.
Similarly, Panel B of figure 1 schematically illustrates a
conventional tabbed container seal lOb including a metal-containing tab 102b,
folded over top 103b of seal 10b. Conventional container seal lOb is
inductively
heat-sealed over a container finish 104b (dotted lines). Shaded area 106b
along the
periphery of seal lOb indicates a high temperature zone where the induction
heating
is most concentrated. High temperature zone 106b corresponds to the area where
the most effective bonding of seal lOb to finish 104b can occur. As can be
seen in
the drawing, high temperature zone 106b is located away from finish 104b
toward
the interior of seal lOb in region 108b adjacent to tab 102b, which can also
lead to
potential seal failure.


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Figure 2 shows an improved tabbed container seal of the invention,
i.e., seal 12. Seal 12 includes metal-free tab members 122, and is inductively
bound
to container finish 124 (dotted lines). Panel A shows tabs 122 extended
outwardly
from container finish 124, while Panel B shows tabs 122 folded up over the top
of
seal 12. Shaded area 126 along the periphery of seal 12 indicates a high
temperature zone where the induction heating is most concentrated. High
temperature zone 126 corresponds to the area where the most effective bonding
of
seal 12 to finish 124 occurs. As can be seen in the drawing, high temperature
zone
126 is evenly distributed in seal 12 over the area of finish 124, providing a
uniform
seal on the container finish. This is due to the absence of metal in tabs 122.
In
contrast, metal-containing tabs, as in conventional seals l0a and lOb in
Figure 1,
can lead to an uneven seal, as described above, since the high temperature
zones
106a and 106b follow the periphery of the seal including the periphery of the
tab
portions 102a and 102b.
Figure 3 illustrates a cross-sectional view of a conventional tabbed
container seal 14 bound over finish 141 of container 143. Tab portion 142 of
seal
14 is indicated by the portion to the right of the imaginary dotted line 145
in the
drawing, while body portion 144 is to the left of dotted line 145. Tab portion
142
and body portion 144 are made up of the same layers 146, 148, 150, 152 and
154.
At least one of layers 146-152 is a layer metal foil, and layer 154 comprises
a
thermoplastic material to make seal 14 inductively sealable. Induction heating
of
seal 14 results in heating of the periphery of tab 142 as well as the
periphery of
body portion 146.
In contrast, Figure 4 shows container seal 16 of the invention bound
over finish 161 of container 163. Tab portions 162 of seal 16 are located in
opposed positions adjacent to body portion 164, which are delineated from one
another by imaginary lines 165 and 167. Tab portions 162 comprise only two of
layers of material (166 and 168, while body portion 164 comprises layers 166,
168,
170, 172 and 174. At least one of layers 170 and 172 is a layer metal foil,
and layer
174 comprises a thermoplastic material. Layers 166 and 168 are metal-free,
making
tabs 162 metal-free, as well. Induction heating of seal 16 results in heating
of the


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periphery of metal-containing body portion 164, but not of metal-free tab
portions
162.
Figures 5-14 shows a number of tab configurations possible with
container seals of the invention. In Figure 5, seal 20 includes two metal-free
tab
portions 202 having a substantially trapezoidal shape. In Figure 6, seal 22
includes
two metal-free tab portions 222 having a substantially semicircular shape. In
Figure
7, seal 24 includes two extended metal-free tab portions 242 having blunt,
rounded
ends. In Figure 8, sea126 includes two metal-free tab portions 262 having a
substantially rectangular shape. In Figure 9, seal 28 includes two metal-free
tab
portions 282 having a skewed tear shape. In Figure 10, seal 30 includes two
metal-
free tab portions 302 in the form of rings. In Figure 11, seal 32 includes two
metal-
free tab portions 322 in the form of semicircles tangent to the seal. In
Figure 12,
seal 34 includes a single metal-free tab portion 342 that is substantially
semicircular
in shape. In Figure 13, seal 36 includes a single metal-free tab portion 362
that is
substantially rectangular in shape. In Figure 14, seal 38 includes a single
metal-free
tab portion 382 that is in the form of a ring.
Figures 15-20 provide schematic cross-sectional views of a number
of illustrative container seals of the invention having two opposed tab
members.
The view in each of Figures 15-20 is a cross-section through a plane
perpendicular
to the cover sheet of the seal, passing through each tab member thereof.
In Figure 15, sea140 comprises metal-free cover sheet 401 and
metal-containing sealant sheet 403 bound to a central portion of cover sheet
401.
Sea140 includes two tab portions 405 formed from regions of cover sheet 401
that
are not bound to sealant sheet 403. Cover sheet 401 comprises a single layer
of
sheet materia1402, which preferably is a polymeric film, a sheet of polymeric
foam,
or a sheet of synthetic fabric material. Sealant sheet 403 comprises a
laminate
composed of three layers, i.e., backing layer 404, metallic layer 406, and
sealant
layer 408. Backing layer 404 can be a tie layer directly bound to sheet
material 402
and metallic layer 406, or can be a layer of adhesive. Metallic layer 406
preferably
comprises a layer of metallic foil, such as aluminum foil. Sealant layer 408
comprises a thermoplastic film or coating directly bound to metallic layer
406.


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In Figure 16, seal 42 comprises metal-free cover sheet 421 and
metal-containing sealant sheet 423 bound to a central portion of cover sheet
421.
Seal 42 includes two tab portions 425 formed from regions of cover sheet 421
that
are not bound to sealant sheet 423. Cover sheet 421 comprises a single layer
of
sheet material 422, which preferably is a polymeric film, a sheet of polymeric
foam,
or a sheet of synthetic fabric material. Sealant sheet 423 comprises a
laminate
composed of five layers, i.e., backing layer 424, which is directly bound to
sheet
materia1422, nietallic layer 426 directly bound to backing layer 424, barrier
layer
430 bound to metallic layer 426 by layer of adhesive 428, and sealant layer
432
directly bound to barrier layer 430.
Backing layer 424 can be a polymeric tie layer directly bound to
sheet material 402 or can be a layer of adhesive. Metallic layer 426
preferably
comprises a layer of metallic foil, such as aluminum foil. Barrier layer 430
preferably comprises a polymeric barrier film, such as a moisture barri.er
film or an
oxygen barrier film. Sealant layer 432 comprises a thermoplastic film or
coating.
In Figure 17, seal 44 comprises metal-free cover sheet 441 and
metal-containing sealant sheet 443 bound to a central portion of cover sheet
441.
Sea144 includes two tab portions 445 formed from regions of cover sheet 441
that
are not bound to sealant sheet 443. Cover sheet 441 comprises a laminate
composed of three layers of material, i.e., outer layer 442 bound to first
backing
layer 446 by adhesive layer 444. Sealant sheet 443 comprises a laminate
composed
of three layers, i.e., second backing layer 448, which is directly bound to
sheet
material first backing layer 446, metallic layer 450 directly bound to second
backing
layer 448, and sealant layer 452 directly bound metallic layer 450.
Outer layer 442 preferably is a layer of polymeric film, a layer of
paper, a layer of polymeric foam, a layer of paper, or a layer of synthetic
fabric.
First backing layer 446 preferably is a polymeric film or layer of polymeric
foam.
Alternatively, layer 444 can be a polymeric film, a layer of paper, or a layer
of
synthetic fabric, which is directly bound to layers 442 and 446. For exarnple
cover
sheet 441 can be a polymer coated paper in which layer 442 is a polymer
coating,
layer 444 is a paper, and layer 446 is a second polymeric coating.


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Second backing layer 448 can be a polymeric tie layer directly bound
to sheet material first backing layer 446 or can be a layer of adhesive.
Metallic
layer 450 preferably comprises a layer of metallic foil, such as aluminum
foil.
Sealant layer 452 comprises a thermoplastic film or coating.
In Figure 18, seal 46 comprises metal-free cover sheet 461 and
metal-containing sealant sheet 463 bound to a central portion of cover sheet
461.
Seal 46 includes two tab portions 465 formed from regions of cover sheet 461
that
are not bound to sealant sheet 463. Cover sheet 461 comprises a laminate
composed of three layers of material, i.e., outer layer 462 bound to first
backing
layer 466 by first adhesive layer 464. Sealant sheet 463 comprises a laminate
composed of five layers, i.e., second backing layer 468, which is directly
bound to
first backing layer 466, metallic layer 470 directly bound to second backing
layer
468, barrier layer 474 bound to metallic layer 470 by second layer of adhesive
472,
and sealant layer 476 directly bound to barrier layer 474.
Outer layer 462 preferably is a layer of polymeric film, a layer of
paper, a layer of polymeric foam or a layer of synthetic fabric. First backing
layer
466 preferably is a polymeric film or layer of polymeric foam. Alternatively,
layer
464 can be a polymeric film, a layer of paper, or a layer of synthetic fabric,
which is
directly bound to layers 462 and 466. For example cover sheet 461 can be a
polymer coated paper in which layer 462 is a polymer coating, layer 464 is a
paper,
and layer 466 is a second polymeric coating.
Second backing layer 468 can be a polymeric tie layer directly bound
to first backing layer 466, or can be a layer of adhesive. Metallic layer 470
preferably comprises a layer of metallic foil, such as aluminum foil. Barrier
layer
472 preferably comprises a polymeric barrier film, such as a moisture barrier
film or
an oxygen barrier film. Sealant layer 476 comprises a thermoplastic film or
coating.
In Figure 19, seal 48 comprises metal-free cover sheet 481 and
metal-containing sealant sheet 483 bound to a central portion of cover sheet
481.
Seal 48 includes two tab portions 485 formed from regions of cover sheet 481
that
are not bound to sealant sheet 483. Cover sheet 481 comprises a laminate


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composed of five layers of material, i.e., outer layer 482 bound to first
backing layer
486 by first adhesive layer 484, and second backing layer 490 bound to first
backing
layer 486 by second layer of adhesive 488. Sealant sheet 483 comprises a
laminate
composed of three layers, i.e., third backing layer 492, which is bound to
second
backing layer 490, metallic layer 494 directly bound to third backing layer
492, and
sealant layer 496 directly bound to metallic layer 494.
Outer layer 482 preferably is a layer of polymeric film, a layer of
paper, a layer of polymeric foam or a layer of synthetic fabric. Each of first
and
second backing layers 486 and 490 preferably is a polymeric film or layer of
polymeric foam. Third backing layer 492 can be a polymeric tie layer directly
bound to second backing layer 490, or can be a layer of adhesive. Metallic
layer
494 preferably comprises a layer of metallic foil, such as aluminum foil.
Sealant
layer 496 comprises a thermoplastic film or coating.
In Figure 20, seal 50 comprises metal-free cover sheet 501 and
metal-containing sealant sheet 503 bound to a central portion of cover sheet
501.
Sea150 includes two tab portions 505 formed from regions of cover sheet 501
that
are not bound to sealant sheet 503. Cover sheet 501 comprises a laminate
composed of five layers of material, i.e., outer layer 502 bound to first
backing layer
506 by first adhesive layer 504, and second backing layer 510 bound to first
backing
layer 506 by second layer of adhesive 508. Sealant sheet 503 comprises a
laminate
composed of five layers, i.e., third backing layer 512, which is bound to
second
backing layer 510, metallic layer 514 bound to third backing layer 512,
barrier layer
518 bound to metallic layer 514 by second layer of adhesive 516, and sealant
layer
520 directly bound to barrier layer 518.
Outer layer 502 preferably is a layer of polymeric film, a layer of
paper, a layer of polymeric foam or a layer of synthetic fabric. Each of first
and
second backing layers 506 and 510 preferably is a polymeric film or layer of
polymeric foam. Third backing layer 512 can be a polymeric tie layer directly
bound to second backing layer 510, or can be a layer of adhesive. Metallic
layer
514 preferably comprises a layer of inetallic foil, such as aluminum foil.
Barrier
layer 518 preferably comprises a polymeric barrier film, such as a moisture
barrier


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film or an oxygen barrier film. Sealant layer 520 comprises a thermoplastic
film or
coating.
Figure 21 illustrates a layout for manufacturing a tabbed container
seal of the invention, such as container seals 20, 22, 24, 26, 28, 30, 32, 34,
36, 38,
40, 42, 44, 46, 48 and 50, described above. Composite web 70 comprises metal-
free cover sheet web 701 and two bands of metal containing sealant sheet
material
702 and 704 bonded to cover sheet web 701. Metal-containing bands 702 and 704
are separated from each other by strip 706 comprising metal-free web 701. In
addition, metal-free strips 708 and 710 flank bands 702 and 704, respectively.
Container seals 712 and 714 are die-cut from composite web 70. Sea1712
includes
a body portion 716 cut from the section of composite web 70 that includes
metal-
containing band 702. Tab portions 718 and 720 of seal 712 are cut from metal-
free
strips 706 and 708, respectively. Similarly, sea1714 includes a body portion
722
cut from the section of composite web 70 that includes metal-containing band
704.
Tab portions 724 and 726 of seal 714 are cut from metal-free strips 706 and
710,
respectively.
Figure 22 illustrates a wide composite web 74 which comprises a
-base web 741 of metal-free cover sheet material having spaced bands 742, 744,
746,
748, 750, and 752 of metal-containing sealant sheet material bound thereto.
Bands
742, 744, 746, 748, 750, and 752 are separated from each other by metal-free
strips
754, 756, 758, 760, and 762. The edges of web 74 include metal-free strips 764
and
766. Composite web 74 cab be slit into three narrower portions, like the web
shown in Figure 21, by cutting along imaginary dotted lines 767 and 769.
Container seals of the invention can be die-cut from the narrower webs in the
manner described for Figure 21, above.
The container seals of the present invention can include any
combination of single-layer or multilayer sealant sheet, cover sheet, and
liner, as
described above. Multilayer sealant sheets, cover sheets, and liners
preferably are
two-layer, three-layer, four-layer or five-layer structures. Multilayer
structures
generally comprise sheets of cellulose pulp, paper, synthetic fabric, polymer
film,
polymer foam, metal foil, and the like, or any combination thereof, adhesively


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bonded together, thermally fused, extruded or coated, to form a unitary
structure, as
is well known in the materials converting and laminating arts. In the
container seals
of the present invention, the cover sheet is metal-free.
In one illustrative use, a container seal of the invention can be die-
cut to an appropriate size and shape and conveniently placed within a
container
closure (e.g., a cap) as a single unit. The container seal is sized and shaped
to fit
securely within the closure and is placed in the closure with its sealing
surface
facing outward. When the container seal includes a liner portion, the liner
preferably is bound to the inside top of the closure by an adhesive, such as a
hot-
melt adhesive. The closure is then secured to the finish of a container (e.g.,
a bottle
or a jar), for example, by torquing a threaded closure onto a threaded finish
of a
container after the container has been filled with a product. Heat is then
applied to
the container seal to bond the sealing surface to the container finish.
Heat can be applied to the container seal inductively or conductively.
In the inductive heating process, a filled container having a container seal
of the
invention secured over its access opening is passed through an induction-
sealing
device in which radio frequency (rf) energy inductively heats the metal foil
layer,
preferably to a temperature in the range of about 65 to about 150 C. For a
container seal having a heat-releasable liner, the heat from metal foil also
liquefies a
layer of wax that tacks the liner to the cover sheet. The wax is then absorbed
by a
wax-absorbent material in contact with the wax layer, causing the liner to
release
and separate from cover sheet. The wax layer that binds the liner to the cover
sheet
preferably is selected to have a melting point in the range of about 65 to
about 150
C.
Upon removal of the closure by a consumer, the liner, if present,
remains in the closure, while the container seal, with its integral tab
portion,
remains bound to the finish of the container as a protective seal. The seal is
peelably removable by a consumer by grasping the tab and pulling the seal off
of
the container finish after the closure is removed.
Liner components preferably include compressible materials, such as
a cellulose pulp material, a polymeric foam, or a polymeric film. Preferred


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polymeric foams include a polyolefin foam, a substituted polyolefin foam, or a
polyurethane foam. Suitable polyolefin foams include foams of polyethylene,
polypropylene, ethylene propylene copolymers, and blends thereof. Non-limiting
examples of suitable substituted polyolefins include polystyrene foam,
polyvinyl
chloride foam, and foam rubber. Preferably, the polyolefin foam is a
polyethylene
foam, more preferably a low-density polyethylene foam.
The liner, when present, preferably has a thickness in the range of
about 15 to about 60 mils (thousandths of an inch), and more preferably about
20 to
about 40 mils.
Cellulose pulp-based substrates, which are commonly used in
closure liners and container seals, can be laminated to other materials such
as a
metal foil, a polymer film, or to a foil/film laminate using conventional
lamination
techniques that are well known in the art.
Polymeric foams useful in the container seals of the present
invention can be secured to other layers of material, such as a metal foil,
paper,
synthetic fabric, or polymer film, by lamination or by extruding the foam
directly
onto a web of the other material, or by extruding a polymeric resin onto a web
of
the polymeric foam, for example. Methods of extruding polymeric foams are well
known in the polymer art. For example, methods of producing polymeric foams
are
described in A. Brent Strong, Plastics Materials and Processing, 2nd Ed.,
Prentice
Hall Inc., Upper Saddle River, NJ, Chapter 17, pp. 589-614 (2000), the
disclosure
of which is incorporated herein by reference. The polymeric foams can be
manufactured using any known foaming process, e.g. by mechanical foaming,
chemical foaming, physical foaming, and the like. Preferably, the polymeric
foam
is formed by chemical foaming with a blowing agent, or gas injection foaming
with
a nucleating agent including passive nucleating agents (e.g., particulate
materials
such as talc) or active nucleating agents (e.g., foaming agents). Blowing
agents are
well known in the polymer arts.
Non-limiting examples of suitable blowing agents include the
following chemicals designated by the U.S. Environmental Protection Agency as
suitable replacements for chlorofluorocarbons (CFC's) and


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hydrochlorofluorocarbons (HCFCs) for Lise as blowing agents in polyolefin
foams:
methylene chloride (dichloromethane); 1,1,1,2-tetrafluoroethane (HFC-134a);
1,1,-difluoroethane (HFC-152a); 1,1,1-trifluoro 2,2-dichloroethane (HCFC-123);
1,1,1-trifluoroethane (HFC-143a); 1,1,1,3,3-pentafluoropropane (HFC-245fa);
saturated light hydrocarbons (C3-C6 hydrocarbons); water; and carbon dioxide.
Other suitable blowing agents include chemical blowing agents such
as carbonate and azo type compounds. Such compounds include, without being
limited thereto, ammonium carbonate, ammonium bicarbonate, potassium
bicarbonate, sodium bicarbonate, diazoaminobenzene, diazoaminotoluene,
azodicarbonamide, diazoisobutyronitrile, and the like.
Metal foils useful in the container seals of the present invention can
comprise any metal that is suitable for use in a closure liner or container
seal, for
example, steel foil (including stainless steel foil), tin foil, aluminum foil
(including
aluminum alloy foils), and the like. Choice of a particular metal will depend
on the
nature of the material to be included in the container to be sealed by the
container
seal of the invention, although aluminum foil is the most common conventional
metal foil used for induction dealing purposes, and is particularly preferred.
Preferably, the metal foil is aluminum foil having a thickness in the range of
about
0.35 mil to about 2 mils.
Materials suitable for use as a polymer film in the container seals of
the invention include, for example, polyolefins such as polyethylene or
polypropylene, polyesters such as PET, functionalized polyolefins such as
ethylene
vinyl alcohol (EVOH) or ethylene vinyl acetate (EVA) polymers, halogenated
polyolefins such as polyvinyl chloride (PVC) or polyvinylidene chloride
(PVdC),
acrylonitrile methacrylate copolymer films (e.g., BAREX film, BP Chemicals,
Inc., Cleveland, OH), and the like. The polymer film can be a single layer of
polymer, or a multilayer structure comprising two or more layers of polymer
bound
together. A particularly preferred polymer film is PET film. Preferably, the
polymer film has a thickness in the range of about 0.5 to about 2 mils.
Adhesives suitable for permanently securing various layers of the
container seals of the invention to one another include epoxy adhesives,
solvent-


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based cements containing synthetic rubber or a phenolic resin, acrylic
adhesives,
urethane adhesives, waxes or any other suitable adhesive, or a tie-layer. Tie-
layers
are often used to provide adhesion between a nonpolar polymer, such as
polyethylene, and a polar polymer such as ethylene vinyl alcohol (EVOH).
Typically, tie-layers are functionalized polyolefins such as ethylene acrylic
acid
copolymers, ethylene vinyl acetate copolymers (EVA), and the like, as is well
known in the art.
One preferred form of adhesive is a solventless adhesive system,
such as MOR-FREE(D 403A/C 117, available from Rohm & Haas Corp.,
Springhouse, PA). Another preferred adhesive is the two part adhesive
available
under the trade name ADCOTE 503 adhesive, from Rohm & Haas Corp, which is
a polyester resin used in combination with a curing agent such as Coreactant
F, also
available from Rohm & Haas Corp. Another suitable adhesive is Airflex 426,
available from Air Products, Inc. Other preferred adhesives include , for
example,
solventless adhesive systems, which are available from Rohm & Haas, and H. B.
Fuller (e.g., Fuller WD4120 and WD4122). Adhesives useful in a variety of
applications are discussed in detail in Arthur H. Landrock, Adhesives
Technology
Handbook, Noyes Publications, Park Ridge, NJ, (1985), incorporated herein by
reference (hereinafter "Landrock").
Releasable adhesives useful for tacking a liner to the cover sheet
include weakly bonding adhesives, such as pressure-sensitive adhesives, wax
and
wax-based adhesives, and the like. Intermittent layers of permanent adhesives
can
also be utilized.
Pressure sensitive adhesives are discussed at pages 174-175 of
Landrock. Such pressure sensitive adhesives include natural rubber adhesives,
natural rubber/styrene-butadiene rubber adhesives, polyisobutylene adhesives,
butyl
rubber adhesives, as well as mixtures of natural rubber with tackifying resins
such
as rosins, petroleum, and terpenes. Other pressure sensitive adhesives include
ethylene/vinyl acetate copolymers tackified with resins or softeners, vinyl
ether
polymers, silicone rubber and silicone resin adhesives, and the like.


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When a pressure sensitive adhesive is used, one surface in contact
with the adhesive can include a release coating, so that the adhesive will
have a
greater affinity for one surface that the other surface with which it is in
contact.
Release coatings include acrylic acid esters of long-chain fatty alcohols,
polyurethanes incorporating long aliphatic chains, cellulose esters,
polytetrafluoroethylene, and the like.
If an adhesive is utilized to bond a polymeric foam and/or a
polymeric film to another layer of material, the bonding surfaces of the
polymer
foam or film can be surface-treated to improve adhesion. Non-limiting examples
of
suitable surface treatments include chromic acid etching, corona treatment,
oxidizing flame treatment, gas plasma treatment, and the like.
Wax-absorbent materials useful in the present invention include
paper, cellulose pulp (e.g., pulp board), or an absorbent synthetic fabric,
such as a
nonwoven fabric, an absorbent polymeric foam, a porous polymeric film, and the
like. The wax-absorbent material can be a single layer of absorbent material,
or a
multilayer structure comprising two or more layers of absorbent material bound
together (e.g, by an adhesive). In any event, the wax-absorbent material is
selected
to be capable of absorbing a sufficient quantity of the wax to cause the liner
to
release from the cover sheet.
The thickness of a wax-absorbent material is selected so that the
material will absorb a sufficient amount of a wax layer to allow the liner to
release
from the cover sheet when the wax is melted. Preferably, the wax absorbent
material has a thickness in the range of about I mil to about 12 mils, more
preferably about 2 mils to about 10 mils, and most preferably about 2.5 mils
to
about 6 mils.
Paper, cellulose pulp, and synthetic fabric materials are useful
components of the container seals of the invention even when a wax layer is
not
utilized. In particular, paper and synthetic fabric materials can be used as a
facing
for a liner or as a facing for the outer surface of the cover sheet. Printed
matter can
be present on the facing to provide product identification information,
product


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promotion information, instructions for use of the container contents, and the
like, if
desired.
Suitable paper and cellulose pulp materials for use in the container
seals of the invention include bleached or unbleached Kraft paper, single-
layer or
multilayer glassine paper, bleached or unbleached cellulose pulp, clay-coated
papers, or any other paper or cellulose sheet material commonly used in
container
seals or-liners in the packaging industry.
Synthetic fabrics that are useful in the container seals of the
invention include nonwoven polyolefin fabrics and nonwoven polyester fabrics.
Suitable nonwoven polyolefin fabrics include nonwoven polyethylene materials,
such as a microporous polyethylene f~ilm or spunbonded high density
polyethylene ,
as well as nonwoven polypropylene, nonwoven ethylene-propylene copolymer, and
nonwoven blends thereof. Suitable nonwoven polyester fabrics include nonwoven
polyethylene terephthalate fabrics and spunlaced DACRON polyester-based
fabrics available from E.I. DuPont de Nemours & Co., Inc. of Wilmington, DE
(Dupont), under the trade name SONTARA . Preferably, the synthetic fabric is
an
absorbent polyethylene non-woven fabric such as TYVEK non-woven fabric,
available from DuPont, or a microporous polyethylene film sold under the trade
name TESLIN by PPG Industries, Inc., Pittsburgh, PA.
A wax layer for tacking a liner to a cover sheet preferably comprises
paraffin, a microcrystalline wax, a polyethylene wax, a polyisobutylene resin,
a
butyl rubber resin, a synthetic wax such as an amide wax (e.g., a stearamide,
an
oleamide, or erucauiide), or any combination thereof. More preferably the wax
layer comprises paraffin, a microcrystalline wax, or a combination thereof.
Most
preferably the wax layer comprises a microcrystalline wax. A wax layer can be
deposited utilizing an emulsion of a wax material, as described above,
suspended in
an aqueous medium. A wax layer, when present preferably has a melting point in
the range of about 65 to about 150 C. Preferably, a wax layer has a thickness
of
about 0.2 to about 2 mils, more preferably about 0.5 to about 0.75 mils.
A barrier film, when present, preferably comprises a polymeric
material having oxygen barrier, moisture barrier, solvent barrier, or
toughness (i.e,


CA 02662268 2009-03-02
WO 2008/039350 PCT/US2007/020387
-24-
puncture resistance) properties, as desired, based on the type of contents
that will be
included within a container sealed by the container seal of the invention. The
barrier film can be a single layer of polymer, or a multilayer structure
comprising
two or more layers of polymer either directly bound to one another or
adhesively
secured to each other. Non-limiting examples of materials that can be used as
a
moisture barrier film include vinyl chloride/vinylidene chloride copolymer
(i.e.,
PVC-PVdC) films marketed by Dow Chemical Company under the trademark
SARAN , polyethylene, oriented polypropylene (OPP), OPP/polyvinyl chloride
(PVC) laminates, and OPP/PVC-PVdC laminates. Non-limiting examples of
materials that can be used as an oxygen barrier film include PVC-PVdC, PET,
PVC-PVdC/PET laminates, acrylonitrile methacrylate copolymer films, PVdC, and
OPP/PVC-PVdC laminates. Non-limiting examples of solvent resistant films
include PET and polyethylene. Non-limiting examples of puncture resistant
films
include PET and PVC. Preferred barrier films are PET, PVdC, and acrylonitrile
methacrylate copolymer films. Preferably the barrier film has a thickness in
the
range of about 0.5 to about 3 mils.
The thermoplastic heat-sealable film or coating at the sealing surface
of the sealant sheet is a thermoplastic material that will soften and bond to
a
container finish with which it is in contact when heated at temperatures
achieved
during typical induction or conduction sealing operations, under the pressure
exerted by the closure on the container seal between the closure and the
container
finish. Typically the pressure on the container seal is achieved by torquing a
closure over the container seal onto a container finish with a torque in the
range of
about 15 inch-pounds to about 90 inch-pounds.
Non-limiting examples of materials that can be used as sealing
surface layer include low-density polyethylene (LDPE), medium density
polyethylene (MDPE), polypropylene (PP), ethylene vinyl acetate (EVA), ionomer
films, and amorphous PET, including heat-sealable polymeric hot melt coatings,
such as an EVA copolymer, a styrene-isoprene-styrene (SIS) copolymer, a
styrene-butadiene-styrene (SBS) copolymer, an ethylene ethyl acrylate
copolymer
(EEA), a polyurethane reactive (PUR) copolymer, and the like. Typically the


CA 02662268 2009-03-02
WO 2008/039350 PCT/US2007/020387
-25-
sealing surface layer is selected to be of the same material as the container
finish or
of a material that is compatible with the container finish. Accordingly, a
polyethylene film would be selected as a heat-sealable film to seal a high-
density
polyethylene container finish. Similarly, a PET film can be used as the heat-
sealable film to seal a PET container finish. Preferably, the heat-sealable
film is
medium density polyethylene, polypropylene, EVA copolymer, or PET. When a
relatively strong, puncture-resistant sealant sheet is desired, a tough
barrier film can
be included over the heat-sealable film.
Thermoplastic materials, many of which are commodity materials
are well known in the art. Non-limiting Examples of thermoplastic materials
are
described in chapter 6 of A. Brent Strong (ed.) Plastics Materials and
Processing,
Second Edition, Prentice-Hall, Inc., Upper Saddle River, NJ (2000), chapter 6
of
which is incorporated herein by reference.
The selection of appropriate shape and dimensions for a container
seal to be used with a particular closure and container combination is routine
for
one of ordinary skill in the packaging art. Typically, the dimensions of the
container seal are chosen to be substantially equal to the inside dimensions
of the
upper surface of the closure, so that the upper surface of the container seal
will fit
snugly within the closure. The thickness of the container seal is selected
based on
the clearance between the upper inside surface of the closure and the finish
of a
complementary container. Preferably, the thickness of the container seal is
selected
so that the container seal is slightly compressed when the material is sealed
between
the closure and a container finish. Such compression aids in forming a fluid
and/or
air-tight seal. Container closures are selected to match container finishes of
complementary dimensions and design, as is well known in the packaging art.
Preferably, the container seal of the invention has an overall
thickness in the range of about 8 to about 85 mils, more preferably about 20
to
about 40 mils. It is preferred that a liner, when present, have a thickness in
the
range of about 5 to about 40 mils. Preferably, the sealant sheet portion has a
total
thickness in the range of about 0.5 to about 10 mils, more preferably about
0.5 to
about 5 mils.


CA 02662268 2009-03-02
WO 2008/039350 PCT/US2007/020387
-26-
The container seals of the present invention can be manufactured
using standard coating and lamination techniques that are well known in the
art.
For example, a web of substrate material (e.g., a polymeric film) and a
thermoplastic film can be laminated to a sheet of metal foil using one or more
conventional adhesives to form a sealant sheet. A surface of the sealant sheet
material can be bonded, in zones (bands), to a metal-free cover sheet
comprising,
for example, a layer of paper laminated to a polymeric barrier film, to form a
multilayer sheet material having strips of metal-free cover sheet material
alternating
with bands of metal-containing, multilayer material comprising both the cover
sheet
and the sealant sheet material. The resulting roll of composite material can
then be
die-cut in register with the metal-containing bands and metal-free strips to
form
container seals of the invention, such that the tab portion of the container
seal is
formed from a metal-free strip and the remainder of the seal is formed from a
metal-
containing band.
In preferred embodiments, the composite web comprises a strip of
metal-free cover sheet material on each side of each band of metal-containing
sealing material. Preferably, the composite web comprises a plurality (e.g.,
two or
more) of metal-containing bands separated from one another by metal-free
strips of
cover sheet material.
The container seals of the present invention can be manufactured to
full machine width in a master roll form, utilizing standard roll coating and
laminating equipment, which are well known in the materi als converting an
processing arts. Typically, the master roll of sheet material is slit to a
desired width
and shipped to a closure manufacturer. The closure manufacturer, in turn, die-
cuts
the slit roll in register with the metal-containing bands and metal-free
strips to the
desired size and shape for use in particular container closures. The die-cut
container seals are then inserted or pressed into the closure and sealed to a
filled
container as described above.
Any common closure design suitable for use with a liner or
container seal can be used in conjunction with the container seals of the
present
invention. Preferred closures include standard, continuous threaded (CT)
closures,


CA 02662268 2009-03-02
WO 2008/039350 PCT/US2007/020387
- 27 -

which are well known in the art. Such closures are described, for example J.
L.
Heid and Maynard A. Joslyn, Eds. Fundamentals of Food Processing Operations
Ingredients, Methods, and Packaging, The AVI Publishing Company, Inc.,
Westport, Connecticut (1967), pp. 649-655.
Numerous variations and modifications of the embodiments
described above may be effected without departing from the spirit and scope of
the
novel features of the invention. No limitations with respect to the specific
embodiments illustrated herein are intended or should be inferred.

Dessin représentatif
Une figure unique qui représente un dessin illustrant l'invention.
États administratifs

Pour une meilleure compréhension de l'état de la demande ou brevet qui figure sur cette page, la rubrique Mise en garde , et les descriptions de Brevet , États administratifs , Taxes périodiques et Historique des paiements devraient être consultées.

États administratifs

Titre Date
Date de délivrance prévu Non disponible
(86) Date de dépôt PCT 2007-09-20
(87) Date de publication PCT 2008-04-03
(85) Entrée nationale 2009-03-02
Demande morte 2011-09-20

Historique d'abandonnement

Date d'abandonnement Raison Reinstatement Date
2010-09-20 Taxe périodique sur la demande impayée

Historique des paiements

Type de taxes Anniversaire Échéance Montant payé Date payée
Le dépôt d'une demande de brevet 200,00 $ 2009-03-02
Taxe de maintien en état - Demande - nouvelle loi 2 2009-09-21 50,00 $ 2009-03-02
Titulaires au dossier

Les titulaires actuels et antérieures au dossier sont affichés en ordre alphabétique.

Titulaires actuels au dossier
TECH-SEAL PRODUCTS, INC.
Titulaires antérieures au dossier
YOUSIF, PAUL E.
Les propriétaires antérieurs qui ne figurent pas dans la liste des « Propriétaires au dossier » apparaîtront dans d'autres documents au dossier.
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Description du
Document 
Date
(yyyy-mm-dd) 
Nombre de pages   Taille de l'image (Ko) 
Abrégé 2009-03-02 1 68
Revendications 2009-03-02 3 125
Dessins 2009-03-02 5 173
Description 2009-03-02 27 1 495
Dessins représentatifs 2009-07-03 1 13
Page couverture 2009-07-03 1 49
PCT 2009-03-02 1 46
Cession 2009-03-02 6 148