TECHNICAL FIELD
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
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.
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.
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.
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.
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
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.
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.
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
FIG. 1A is a perspective view, illustrating a prior art thermoformed container having a resealable lid.
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.
FIG. 2 is an exploded view, illustrating an embodiment of the present invention.
FIG. 3 is a perspective view, illustrating the embodiment of FIG. 2 in an assembled state.
FIG. 4A is a perspective view, illustrating the embodiment of FIG. 3 with the resealable cover peeled back to an open position.
FIG. 4B is a section view, illustrating the embodiment of FIG. 4A.
FIG. 5A is a perspective view, illustrating an embodiment of the present invention.
FIG. 5B is a perspective view, illustrating the embodiment of FIG. 5A with the resealable cover moved to the open position.
FIG. 6A is a perspective view, illustrating a layer of the cover of an embodiment of the present invention.
FIG. 6B is a perspective view, illustrating an embodiment of the present invention employing the layer of FIG. 6A.
FIG. 6C is a perspective view, illustrating an embodiment of the present invention.
FIG. 6D is a perspective view, illustrating the embodiment of FIG. 6C with the resealable cover moved to the open position.
FIG. 7 is a perspective view, illustrating an embodiment of the present invention.
FIG. 8 is a perspective view, illustrating the embodiment of FIG. 7 after heat sealing.
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.
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.
FIG. 10 is a perspective view, illustrating an embodiment of the present invention.
FIG. 11 is a top view, illustrating the embodiment of FIG. 10 after heat sealing.
FIG. 12 is a perspective view, illustrating the embodiment of FIG. 11, with the resealable cover portion moved to the opened position.
FIG. 13 is a perspective view, illustrating part of a manufacturing process for making an embodiment of the present invention.
FIG. 14 is a side view, illustrating part of a manufacturing process for making an embodiment of the present invention.
DETAILED DESCRIPTION OF EMBODIMENTS
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.
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.
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.
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.
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.
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.
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.
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 ¼ 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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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 in2/24 hrs, or more preferably less than 10 cc/100 in2/24 hrs, or most preferably less than 0.1 cc/100 in2/24 hrs.
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.
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.
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.
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.
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.
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.
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.
Patent Application
20100172604
