U.S. patent application number 12/348980 was filed with the patent office on 2010-07-08 for reclosable container with resealable flexible cover and method for manufacturing the same.
This patent application is currently assigned to PRINTPACK ILLINOIS, INC.. Invention is credited to Anthony J. Alvarez, Thomas Andersson, Edward J. Cigallio, Ronald W. Komro.
Application Number | 20100172604 12/348980 |
Document ID | / |
Family ID | 42077705 |
Filed Date | 2010-07-08 |
United States Patent
Application |
20100172604 |
Kind Code |
A1 |
Andersson; Thomas ; et
al. |
July 8, 2010 |
Reclosable Container with Resealable Flexible Cover and Method for
Manufacturing the Same
Abstract
A reclosable container with a resealable, flexible cover portion
that is easy to use and a method of manufacturing the same. The
reclosable container comprises a container body having a storage
space and an opening providing access to the storage space. The
container body includes a base portion and a resealable cover
portion having an inner layer, an outer layer, and a
pressure-sensitive adhesive affixing the inner layer to the outer
layer. The inner layer of the resealable cover portion is heat
sealed to the base portion about the opening thereby forming a
heat-sealed region where the inner layer contacts and is heat
sealed to the base portion. The inner layer of the resealable cover
portion has a cut inside the heat-sealed region such that when the
resealable cover portion is pulled apart from the base portion, the
inner layer, the outer layer, and the pressure-sensitive adhesive
are together lifted away from the opening, but the inner layer
remains attached to the base portion in and adjacent to the
heat-sealed region such that the pressure-sensitive adhesive
contacting the inner layer in and adjacent to the heat-sealed
region is exposed.
Inventors: |
Andersson; Thomas;
(Helsingborg, SE) ; Cigallio; Edward J.;
(Douglasville, GA) ; Alvarez; Anthony J.;
(Atlanta, GA) ; Komro; Ronald W.; (Smyrna,
GA) |
Correspondence
Address: |
SUTHERLAND ASBILL & BRENNAN LLP
999 PEACHTREE STREET, N.E.
ATLANTA
GA
30309
US
|
Assignee: |
PRINTPACK ILLINOIS, INC.
Elgin
IL
|
Family ID: |
42077705 |
Appl. No.: |
12/348980 |
Filed: |
January 6, 2009 |
Current U.S.
Class: |
383/211 |
Current CPC
Class: |
B65D 2575/365 20130101;
B65D 2575/368 20130101; B65D 75/366 20130101; B65D 75/5838
20130101 |
Class at
Publication: |
383/211 |
International
Class: |
B65D 33/00 20060101
B65D033/00 |
Claims
1. A reclosable container comprising: a container body having a
storage space and an opening providing access to said storage
space, the container body comprising a base portion and a
resealable cover portion having an inner layer, an outer layer, and
a pressure-sensitive adhesive affixing said inner layer to said
outer layer; wherein said inner layer of said resealable cover
portion is heat sealed to said base portion about said opening
thereby forming a heat-sealed region where said inner layer
contacts and is heat sealed to said base portion, said inner layer
of said resealable cover portion having a cut inside said
heat-sealed region such that when said resealable cover portion is
pulled apart from said base portion, said inner layer, said outer
layer, and said pressure-sensitive adhesive are together lifted
away from said opening, but said inner layer remains attached to
said base portion in and adjacent to said heat-sealed region such
that said pressure-sensitive adhesive contacting said inner layer
in and adjacent to said heat-sealed region is exposed.
2. The reclosable container of claim 1, wherein said resealable
cover portion is a flexible laminate in which said inner layer,
said outer layer, and said pressure-sensitive adhesive are
continuous across said resealable cover portion.
3. The reclosable container of claim 1, said resealable cover
portion further comprising a pull tab, said pull tab formed by a
second cut in said inner layer of said resealable cover portion,
said second cut located outside of said heat sealed region.
4. The reclosable container of claim 1, said resealable cover
portion further comprising a pull tab, said pull tab formed by a
second cut in said inner layer of said resealable cover portion and
said container body, said second cut passing through a portion of
said heat sealed region
5. The reclosable container of claim 1, said inner layer comprising
a thermoplastic material.
6. The reclosable container of claim 1, said outer layer comprising
a thermoplastic material.
7. The reclosable container of claim 1, wherein said cut has an
open geometry.
8. The reclosable container of claim 1, wherein said inner layer
has a gas permeability of less than 0.1 cc/100 in.sup.2/24 hrs.
9. The reclosable container of claim 1, wherein the inner layer
comprises ethylene vinyl alcohol.
10. The reclosable container of claim 1, wherein said base portion
comprises a substantially rigid material and said resealable cover
portion comprises a flexible material.
11. The reclosable container of claim 1, wherein said base portion
and said resealable cover portion comprise a flexible material.
12. A reclosable container comprising: a container body having a
storage space and an opening providing access to said storage
space, said container body comprising a base portion and a
resealable cover portion having an inner layer, an outer layer, and
a pressure-sensitive adhesive affixing said inner layer to said
outer layer, said resealable cover portion being a flexible
laminate in which said inner layer, said outer layer, and said
pressure-sensitive adhesive are continuous across said resealable
cover portion; said inner layer being sealed to said base portion
along a sealed region about said opening of said container body;
said resealable cover portion configured to separate, exposing said
pressure-sensitive adhesive in and adjacent to said sealed region
while covering said pressure-sensitive adhesive facing said opening
with said inner layer when said resealable cover portion is lifted
away from said base portion.
13. The reclosable container of claim 12, said inner layer of said
resealable cover portion having a cut inside said heat-sealed
region.
14. The reclosable container of claim 13, said resealable cover
portion further comprising a pull tab, said pull tab formed by a
second cut in said inner layer of said resealable cover portion,
said second cut located outside of said heat sealed region.
15. The reclosable container of claim 13, said resealable cover
portion further comprising a pull tab, said pull tab formed by a
second cut in said inner layer of said resealable cover portion and
said base portion, said second cut passing through a portion of
said heat sealed region
16. The reclosable container of claim 12, said inner layer
comprising a thermoplastic material.
17. The reclosable container of claim 12, said outer layer
comprising a thermoplastic material.
18. The reclosable container of claim 12, wherein said inner layer
is heat-sealed to said base portion along a sealed region about
said opening of said container body.
19. The reclosable container of claim 13, wherein said cut has an
open geometry.
20. A method of manufacturing a reclosable container comprising:
providing a container body having a storage space and an opening
providing access to said storage space; loading a product into said
storage space; providing a flexible laminate having an inner layer,
an outer layer, and a pressure-sensitive adhesive affixing said
inner layer to said outer layer; cutting said inner layer of said
flexible laminate to form a separating cut, said separating cut
passing through said inner layer but not through said outer layer;
and sealing said flexible laminate to said container body about
said opening along a sealed region such that at least a portion of
said separating cut lies inside said sealed region after said
product is loaded into said storage space and said separating cut
is cut into said inner layer.
21. The method of claim 20, said inner layer comprising a
thermoplastic material.
22. The method of claim 20, said outer layer comprising a
thermoplastic material.
23. The method of claim 20, wherein said inner layer is sealed to
said container body by a heat-sealing process.
24. The method of claim 20, further comprising cutting said inner
layer of said flexible laminate to form a second separating cut to
form a pull tab, said second separating cut passing through said
inner layer but not through said outer layer.
25. The method of claim 20, wherein said separating cut has an open
geometry.
26. The method of claim 20, wherein said separating cut faces said
container body inside said sealed region.
Description
TECHNICAL FIELD
[0001] This invention relates to product packaging. More
particularly, this invention relates to a reclosable container with
a resealable, flexible cover and a method for manufacturing the
same.
BACKGROUND OF THE INVENTION
[0002] Flexible packaging materials are formed into vessels to
encapsulate many different products. Many of these products are
packaged in bulk so as to allow the user to open the package and
use what is needed at that time. The opened package will then
contain some unused portion of the product. The packaging industry
has developed several means to allow reclosure of the opened
package to prevent spoilage, spillage, or inadvertent use of the
remaining product. Zippers, fitments, adhesive patches, and other
fasteners have been used on different products, but each mechanism
is best-suited for only a narrow range of products.
[0003] It has become increasingly popular to package products using
thermoforming processes. These processes involve drawing a heated
thermoforming film into a cavity by vacuum and then cooling the
film to a semi-rigid vessel. The container is then filled with
product and a top layer of film is used to seal the top of the
container. The top layer is typically heat sealed to the
thermoformed bottom. While such a process is a cost-effective
method of sealing the product, opening the vessel destroys the seal
between the top layer and the thermoformed bottom. Thus, the user
cannot reseal the vessel without adding a new adhesive between the
top layer and the thermoformed bottom.
[0004] Other packaging systems have since been developed to address
the problem of resealing thermoformed vessels. One example of such
a packaging system is illustrated in FIGS. 1A and 1B. As shown in
FIG. 1A, a container 10, a thermoformed vessel, includes a
resealable cover 12 having an integrated pull tab 14. Turning to
FIG. 1B, the viewer will note that pulling the pull tab 14 causes
the cover 12 to peel off of a top layer 24 of the container 10.
This reveals an opening 21 in the top layer 24 and provides access
to the contents stored in an interior 20. A cover footprint 18
indicates the region of the top layer 24 that was covered by the
cover 12 when it is positioned in the closed position of FIG. 1A. A
pressure-sensitive adhesive 16 is provided around the bottom
perimeter of the cover 12. The pressure-sensitive adhesive 16
adheres to the top layer 24 in the region of the cover footprint 18
when the cover 12 is returned to the closed position, thereby
hermetically sealing the interior 20.
[0005] As illustrated in FIG. 1B, the container 10 has a
thermoformed bottom 22 with an interior 20. The top layer 24
includes an opening 28. The opening 28 is typically die cut into
the top layer 24 before the top layer 24 is heat sealed to the rim
of the thermoformed bottom 22. The pressure-sensitive adhesive 16
is affixed to the bottom of the cover 12. The cover 12 is typically
affixed to the top layer 24 with the pressure-sensitive adhesive 16
before the top layer 24 is heat sealed to the thermoformed bottom
22.
[0006] Although such a packaging assembly achieves the objective of
resealability, the packaging assembly is needlessly complex and
expensive to manufacture. Such a packaging design is also overly
cumbersome to open and close for some demographic groups. Even
more, such a design allows the cover 12 to be inadvertently removed
from the top layer 24. Once the cover 12 is removed from the top
layer 24 it is particularly difficult to realign the cover 12 with
the opening 21 of the top layer 24. In some cases, the cover 12 may
even be misplaced or lost. Such a design also limits the size of
the opening 21 providing access to the interior 20 of the
container. Also, it is not uncommon for air to be entrapped between
the cover 12 and top layer 24 around the opening 21. The entrapped
air bubbles often appear as "blisters" on cover 12 which may lead
the consumer to doubt the hermetic seal of the packaging.
SUMMARY OF THE INVENTION
[0007] This invention solves the above-described problems in the
prior art by providing a reclosable container with a resealable,
flexible cover portion that may be efficient to manufacture and/or
easy to use. The reclosable container comprises a container body
having a storage space and an opening providing access to the
storage space. The container body includes a base portion and a
resealable cover portion having an inner layer, an outer layer, and
a pressure-sensitive adhesive affixing the inner layer to the outer
layer. The inner layer of the resealable cover portion is heat
sealed to the base portion about the opening thereby forming a
heat-sealed region where the inner layer contacts and is heat
sealed to the base portion. The inner layer of the resealable cover
portion has a cut inside the heat-sealed region such that when the
resealable cover portion is pulled apart from the base portion, the
inner layer, the outer layer, and the pressure-sensitive adhesive
are together lifted away from the opening, but the inner layer
remains attached to the base portion in and adjacent to the
heat-sealed region such that the pressure-sensitive adhesive
contacting the inner layer in and adjacent to the heat-sealed
region is exposed.
[0008] In another aspect, the present invention comprises a method
of manufacturing a reclosable container comprising (1) providing a
container body having a storage space and an opening providing
access to the storage space, (2) loading a product into the storage
space, (3) providing a flexible laminate having an inner layer, an
outer layer, and a pressure-sensitive adhesive affixing the inner
layer to the outer layer, (4) cutting the inner layer of the
flexible laminate to form a separating cut, the separating cut
passing through the inner layer but not through the outer layer;
and (5) sealing the flexible laminate to the container body about
the opening along a sealed region such that at least a portion of
said separating cut lies inside said sealed region after the
product is loaded into the storage space.
[0009] Other objects, features and advantages of this invention
will be apparent from the following detailed description of
embodiments, claims, and drawings.
BRIEF DESCRIPTION OF DRAWINGS
[0010] FIG. 1A is a perspective view, illustrating a prior art
thermoformed container having a resealable lid.
[0011] FIG. 1B is a perspective view, illustrating the prior art
thermoformed container of FIG. 1A with the resealable cover peeled
back to an open position.
[0012] FIG. 2 is an exploded view, illustrating an embodiment of
the present invention.
[0013] FIG. 3 is a perspective view, illustrating the embodiment of
FIG. 2 in an assembled state.
[0014] FIG. 4A is a perspective view, illustrating the embodiment
of FIG. 3 with the resealable cover peeled back to an open
position.
[0015] FIG. 4B is a section view, illustrating the embodiment of
FIG. 4A.
[0016] FIG. 5A is a perspective view, illustrating an embodiment of
the present invention.
[0017] FIG. 5B is a perspective view, illustrating the embodiment
of FIG. 5A with the resealable cover moved to the open
position.
[0018] FIG. 6A is a perspective view, illustrating a layer of the
cover of an embodiment of the present invention.
[0019] FIG. 6B is a perspective view, illustrating an embodiment of
the present invention employing the layer of FIG. 6A.
[0020] FIG. 6C is a perspective view, illustrating an embodiment of
the present invention.
[0021] FIG. 6D is a perspective view, illustrating the embodiment
of FIG. 6C with the resealable cover moved to the open
position.
[0022] FIG. 7 is a perspective view, illustrating an embodiment of
the present invention.
[0023] FIG. 8 is a perspective view, illustrating the embodiment of
FIG. 7 after heat sealing.
[0024] FIG. 9A is a partial section view, illustrating the top
portion of the embodiment of FIG. 8 with the resealable cover
portion in the closed position.
[0025] FIG. 9B is a partial section view, illustrating the top
portion of the embodiment of FIG. 8 with the resealable cover
portion in the opened position.
[0026] FIG. 10 is a perspective view, illustrating an embodiment of
the present invention.
[0027] FIG. 11 is a top view, illustrating the embodiment of FIG.
10 after heat sealing.
[0028] FIG. 12 is a perspective view, illustrating the embodiment
of FIG. 11, with the resealable cover portion moved to the opened
position.
[0029] FIG. 13 is a perspective view, illustrating part of a
manufacturing process for making an embodiment of the present
invention.
[0030] FIG. 14 is a side view, illustrating part of a manufacturing
process for making an embodiment of the present invention.
DETAILED DESCRIPTION OF EMBODIMENTS
[0031] As summarized above, this invention encompasses a reclosable
container with a resealable, flexible cover that is easy to
manufacture and use. This invention also encompasses a method for
manufacturing such a reclosable container.
[0032] FIG. 2 is an exploded view of one embodiment of the present
invention illustrating the components of a container 31. The
container 31 includes four layers--a container bottom 32 (also
referred to as a base portion) and a resealable cover portion 34
which includes an inner layer 40, a pressure-sensitive adhesive
layer 42, and an outer layer 44. The container bottom 32, which may
be a thermoformed structure, has a storage space 38 which is
dimensioned to contain a specific amount of a bulk product. An
opening 36 is provided in the top of the container bottom 32 to
provide access to the contents of the storage space 38. A rim 37 is
provided around the perimeter of the opening 36 to provide a
contact surface for heat sealing the inner layer 40 to the base
portion 32 as will be described in greater detail subsequently.
[0033] The term "layer" as used herein generally refers to a depth
of material of a laminated structure. It should be noted that a
single layer may comprise multiple sub-layers. For example, the
inner layer 40 may comprise multiple films or sub-layers that are
co-extruded or otherwise laminated together.
[0034] The inner layer 40 and the outer layer 44 may be sheets of
thermoplastic film which are adhesively affixed together by the
pressure-sensitive adhesive layer 42. The inner layer 40 includes a
cut 35 which passes entirely through the inner layer 40 but not
through the outer layer 44. The cut 35 may optionally pass through
the pressure-sensitive adhesive layer 42. Although the cut 35 is
illustrated as a dashed line, it is preferred that the cut 35 form
a continuous U-shaped cut of the inner layer 40. A perforated cut
pattern may also be used depending on the adhesive strength of the
pressure-sensitive adhesive layer 42 and the shear strength of the
inner layer 40. For reasons that will soon be more apparent, the
cut 35 faces the storage space 38 and lies inside the opening 36
when the inner layer 40 is sealed to the container bottom 32. As
such, the cut 35 lies entirely inside the region of the inner layer
40 that is heat sealed to the rim 37. A second cut 48 is provided
near one end of the resealable cover portion. As with the cut 35,
the second cut 48 passes through the entirety of the inner layer 40
but does not pass through the outer layer 44. The cut 48 lies
outside of the heat-sealed region.
[0035] FIG. 3 illustrates the embodiment of FIG. 2 in the assembled
state. The resealable cover portion 34, which is a continuous
laminate structure comprising the inner layer 40, the
pressure-sensitive adhesive layer 42, and the outer layer 44,
extends across the top of the container, hermetically sealing the
product contained in the container bottom 32 from the
atmosphere.
[0036] Turning to FIG. 4A, the viewer will see that lifting the
resealable cover portion 34 from the container bottom 32 causes the
inner layer 40 to separate along the aforementioned cut 35 and the
second cut 48 of FIG. 2. As illustrated in FIG. 4A, the portion of
the inner layer 40 remaining along the edge of the resealable cover
adheres to the pressure-sensitive adhesive 42 and forms a pull tab.
An exposed region 50, a portion of the container bottom 32, faces
the pull tab when the pull tab is in the closed position. This
separation exposes the pressure-sensitive adhesive layer 42, which
may remain affixed to the outer layer 44, along the portion of the
outer layer 44 which normally mates with the heat-sealed region of
the inner layer 40 when the container is in the closed position of
FIG. 2. The pressure-sensitive adhesive layer 42 may also remain
affixed to the inner layer 40. Referring back to FIG. 4A, an
opening 46 is formed along the cut 35, and the portion of the inner
layer 40 facing the storage space 38 through the opening 46 remains
affixed to the outer layer 44 by the pressure-sensitive adhesive
42. If the present U-shaped cut pattern is employed, the uncut
portion of the inner layer 40 lying along the heat-sealed portion
of the inner layer 40 prevents the resealable cover portion from
being inadvertently detached from the container bottom 32. The
reader should appreciate that the cut 35 may assume many different
shapes than the illustrated U-shape cut pattern. Any open
geometrical cut pattern would restrict the resealable cover from
being inadvertently detached. The term "open geometry" or "open
geometrical" as used herein refers to and consists of all open
polygonal and open curvilinear shapes.
[0037] Once the user removes the desired amount of product from the
storage space 38 through the opening 46, the container may be
resealed by returning the resealable cover portion 34 to the closed
position of FIG. 3 and applying pressure to the top layer 44 along
the heat-sealed region. This causes the pressure-sensitive adhesive
layer 42 to reaffix the outer layer 44 to the inner layer 40.
[0038] FIG. 4B illustrates in greater detail how a portion 49 of
the inner layer 40 remains affixed to the container bottom 32
adjacent to the heat-sealed portion 47 of the inner layer 40 when
the inner layer 40 separates along the cut 35. This provides
additional contact area for resealing the container. Such a feature
is particularly beneficial in comparison to "resealable" containers
which rely on the frangibility of the inner layer at the heat seal
to open the container, since a conventional 1/4 inch heat seal bead
typically does not provide sufficient contact area for effective
resealing. Similarly, the cut 35 provides for a clean separation of
the inner layer 40 at the cut 35 and a smoother reseal than
embodiments which require the user to tear the inner layer at the
heat seal. Furthermore, die cutting the inner layer allows for more
design flexibility when selecting a material for the inner layer 40
or a thickness for the inner layer 40. Otherwise, the barrier
properties of the inner layer 40 and the "ease of opening" are
competing design concerns in which one design criteria must be
sacrificed in order to improve performance for the other design
criteria.
[0039] As an alternative to the previous embodiment, it should be
noted that the exposed region 50 may also be heat sealed to the
inner layer 40. Such an embodiment is illustrated in FIGS. 5A and
5B. In this embodiment, an additional cut 80 is provided in the
container bottom 32 adjacent to the cut 48. It should be noted that
a similar result could be accomplished by making a single cut that
passes through both the container bottom 32 and the inner layer 40
after the resealable lid is heat sealed to the container bottom 32.
It would be further preferable to use a perforated cut pattern for
this cut, since such a cut pattern would allow the user to easily
snap off a portion 82 of the container bottom 32 (the portion
corresponding to the exposed region 50 in FIG. 4A) when lifting the
cover from the container bottom 32 the first time. FIG. 5B
illustrates how the portion 82 remains attached to the resealable
cover and acts as a pull tab when snapped off of the container
bottom 32.
[0040] Another embodiment of the present invention is illustrated
in FIGS. 6A and 6B. In this embodiment, a second cut 52 is provided
near one end of the resealable cover at the corner. As with the cut
35, the second cut 52 passes through the entirety of the inner
layer 40 but does not pass through the top layer 44. The cut 52
lies outside of the heat-sealed region. As shown in FIG. 6B, the
cut 52 causes the inner layer 40 to separate along the cut 52 when
the resealable cover is lifted from the container bottom 32. The
portion of the inner layer 40 remaining at the corner of the
resealable cover adheres to the pressure-sensitive adhesive 44 and
forms a pull tab. An exposed region 54, a portion of the container
bottom 32, faces the pull tab when the pull tab is in the closed
position.
[0041] It should be noted that, like the embodiment of FIG. 5B, the
embodiment of FIG. 6B may also be modified by heat sealing the
inner layer 40 to the exposed region 54. Such an embodiment is
illustrated in FIGS. 6C and 6D. In this embodiment, a further cut
84 is provided in the container bottom 32 adjacent to the cut 52. A
similar result could be accomplished by making a single cut that
passes through both the container bottom 32 and the inner layer 40
after the resealable cover portion is heat sealed to the container
bottom 32. FIG. 6D illustrates how a portion 86 remains attached to
the resealable cover and acts as a pull tab when snapped off of the
container bottom 32.
[0042] Yet another embodiment of the present invention is
illustrated in FIGS. 7, 8, 9A, and 9B. In this embodiment, a
container 101 is produced from a single laminate sheet 103 as
illustrated in FIG. 7. The laminate sheet 103 includes an inner
layer 40 which is affixed to an outer layer 44 by a
pressure-sensitive adhesive layer 42. A die cut 88 is provided
through the inner layer 40 as before. In this embodiment, a closed
geometrical pattern, such as a rectangle with rounded corners, is
used. The laminate sheet 103 is preferably substantially
rectangular in shape having a top 104, a bottom 102, a first end 98
and a second end 100. The die cut 88 is preferably positioned near
the top 104 of the laminate sheet.
[0043] Turning to FIG. 8, the first end 98 and the second end 100
are then affixed together to form a fin seal 90. A heat seal 96 is
then created at the bottom 102 of laminate 103. A second heat seal
94 is provided near the top of the container 101 passing through
the region bounded by the die cut 88. The container 101 is
preferably filled with a bulk product before the second heat seal
94 is formed. A portion of the container 101 above the heat seal 94
may optionally be left unsealed to provide a top opening 92 as
shown.
[0044] FIGS. 9A and 9B are section views of the region around the
heat seal 94. As shown in FIG. 9A, when the first end and second
end of the laminate sheet are joined and the bottom is heat sealed,
the container 101 generally forms a bag having a front portion 106
and a back portion 108. The inner layer 40 of the front portion 106
faces the inner layer 40 of the back portion 106. Thus, the heat
seal 94 lying within the region of the die cut 88 joins the two
parts of the inner layer 40 together. FIG. 9A shows the container
101 in the closed position.
[0045] As shown in FIG. 9B, to open the container 101, the front
portion 106 and the back portion 108 are pulled apart causing a
portion of the inner layer 40 lying within the die cut to separate
from the pressure-sensitive adhesive layer 42. This allows the user
to access the contents of the container 101 through the top opening
92. The container 101 may then be reclosed by pressing the portion
of inner layer 40 removed from the die cut 88 back against the
pressure-sensitive adhesive layer 42.
[0046] Yet another embodiment of the present invention is
illustrated in FIGS. 10-12. As shown in FIG. 10, a container 111
comprises a laminate sheet 115 having an inner layer 40 affixed to
an outer layer 44 by a pressure-sensitive adhesive layer 42. The
laminate sheet 115 has a top portion 116 and a bottom portion 118.
Two die cuts 110 and 112 are provided in the top portion 116 of the
laminate sheet 115. The die cuts 110 and 112 pass through the inner
layer 40 but not the outer layer 44. The die cut 112 extends across
the width of the laminate sheet 115. The die cut 110 forms an open
geometrical shape having two ends which turn back towards the die
cut 112 before terminating. These "hook" shapes restrict the extent
that the resealable cover portion of the container 111 can be
opened and prevents the user from inadvertently tearing the inner
layer 40 when opening the container 111.
[0047] Turning to FIG. 11, the container 111 is formed by folding
the top portion of the laminate sheet on top of the bottom potion
of the laminate sheet and the two portion are heat sealed together
to form a heat seal 114 along two sides of the perimeter of the
container 111 and across the width of the container 111 between the
die cuts 112 and 110 as shown.
[0048] As shown in FIG. 12, the container 111 is opened by pulling
the outer edge 126 of the top portion 116 away from the outer edge
126 of the bottom portion 118. This causes the inner layer 40 of
the top portion 116 to separate at the die cuts 110 and 112. The
heat sealed portion 122 of the inner layer 40 of top portion 116
remains affixed to the inner layer 40 of the bottom portion 118.
The portion of the inner layer 40 of the top portion 116 lying
inside the die cut 110 remains affixed to the top portion 116 due
to the pressure-sensitive adhesive layer. This separation of the
inner layer 40 of the top portion 116 provides access to an opening
120 for accessing the contents stored in the container 111. To
reseal the container 111, the top portion 116 is laid back on top
of the bottom portion 118 and pressure is applied along the heat
sealed portion 122 to cause the heat sealed portion 122 to reaffix
to the pressure-sensitive adhesive layer of the top portion
116.
[0049] Various materials may be used for the different portions and
layers of the various container configurations shown and described
herein. The inner layer 40 and the outer layer 44 may comprise the
same or different material, but in some embodiments, both layers
may comprise a thermoplastic polymer material. In some embodiments,
the inner layer 40 comprise an oxygen barrier material such as
ethylene vinyl alcohol (EVOH). In a certain embodiment, the inner
layer may have a gas permeability of less than 100 cc/100
in.sup.2/24 hrs, or more preferably less than 10 cc/100 in.sup.2/24
hrs, or most preferably less than 0.1 cc/100 in.sup.2/24 hrs.
[0050] The reader will note that in the embodiments of the
invention illustrated and described herein, both the inner layer 40
and the outer layer 44 extend across the container opening when the
container is resealed. This is particularly beneficial when using
the containers to store food and other products which are
susceptible to spoiling since the gas barrier material (the inner
layer 40) is substantially continuous across the opening.
[0051] Although there are many other advantages that may be
realized using such container configurations, one advantage is that
many embodiments of the present invention may be easily
manufactured using a fully-automated assembly line process. Several
of the stages of such a process are illustrated in FIGS. 13 and
14.
[0052] As illustrated in FIG. 13, a laminated sheet 62 which
includes the inner layer 40, the pressure-sensitive adhesive layer
42 and the outer layer 44 passes through a die cutting device 60
with the inner layer 40 facing the cutting tool. The die cutting
device 60 includes a cutting die which cuts through the laminated
sheet 62 to a designated depth. As noted previously, the laminated
sheet 62 should be cut to such a depth that the cut pattern passes
entirely through the inner layer 40 but not through the outer layer
44. The die cutting device 60 cuts a plurality of cuts 35 into the
laminated sheet 62 at a time as the laminated sheet 62 is fed
through the die cutting device 60 along a direction of feed. It
should also be noted that other cutting tools may be used to
provide the cuts 35 in the laminated sheet 62. For example, a laser
cutting tool may be used in place of a cutting die.
[0053] As illustrated in FIG. 14, the laminated sheet 62, being
precut with the cuts 35, is fed together with a bottom sheet 64 to
a heat sealer 66. In the present embodiment, the bottom sheet 64
comprises a continuous sheet of thermoformed container bottoms 32.
Each container bottom 32 is filled with an amount of bulk product
at a previous stage in the automated assembly process. When passing
through the heat sealer 66, a heat-sealing process is used to seal
the laminated sheet 62 to the bottom sheet 64, thereby sealing the
bulk product in the containers. Each cut 35 is aligned with one of
the container bottoms 32 in accordance with the previously
described container configuration. After passing through the heat
sealer 66, a sealed container sheet 74, containing a continuous
sheet of heat-sealed containers, is fed to a die cutter 68 which
separates sealed the container sheet 74 into individual cut
containers 72. The cut containers 72 fall into a hopper 70 where
they are collected and sent to a sorting and/or packaging
stage.
[0054] The foregoing process may be easily modified to add a pull
tab to each container. If employing a pull tab shown in the
embodiment of FIG. 2, an additional cut would be provided across
the width of the laminated sheet 62 (transverse to the feed
direction of the laminated sheet 62) ahead of each row of cuts 35.
If employing a pull tab shown in the embodiment of FIG. 6B an
additional angled cut would be provided ahead of each cut 35. If
"snap off" type pull tabs are to be used, the additional perforated
cut could be provided by the die cutter 68.
[0055] Those that are skilled in the art by now will appreciate
that the foregoing manufacturing process can also be easily
modified to produce the embodiments of the present invention
illustrated in FIGS. 7-12 which comprise a single laminate sheet
without a thermoformed bottom. The modified process would still
utilize a die cutting stage, but would also include additional
folding and heat sealing stages before the container is filled with
the bulk product.
[0056] The invention being thus described, it will be obvious that
the same may be varied in many ways. Such variations are not to be
regarded as a departure from the spirit and scope of the invention,
and all such modifications as would be obvious to one skilled in
the art are intended to be included within the scope of the
following claims.
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