Patent Application
20120005994
The present invention relates to packaging and more particularly to thermoformed packages with tamper evident seals.
Thermoformed packages are used in a wide variety of applications. Typical thermoformed packages are relatively inexpensive to manufacture and provide sturdy, aesthetically pleasing packaging. Also, thermoformed packages are typically transparent, thereby allowing consumers to visually inspect the packaged goods. This makes thermoformed packages particularly well suited for use in point of sale packaging. Thermoformed packages are often manufactured from a clamshell with top and bottom parts that are joined by a hinge. This keeps the top and bottom parts together facilitating manufacture and packaging, and making it easier for consumers to repeatedly open and close the package.
Thermoformed packages are often sealed around the peripheral edges to prevent access to the package. In clamshell packages, the seal may be formed only along the edge opposite the hinge. This can help to reduce theft and damage to the packaged goods. Although providing a level of security, these seals are often essentially permanent and can make it difficult for the end consumer to open the package. To address this issue, thermoformed packages have been provided with tear strips and/or removable components that allow access to the contents of the package without requiring that the permanent seal be broken. Tear strips and removable components can provide the added benefit of providing a tamper-evident seal. For example, a cu
A variety of thermoformed packages with tamper evident seals are available in the market. In one conventional construction, a clamshell package includes top and bottom parts that are joined along a hinge. The package is sealed by forming a permanent seal that joins the top part to the bottom part along the edge opposite the hinge. The permanent seal may be formed by ultrasonic welding, heat staking or stitch welding. The package includes a tear strip that can be pulled up through a perforation line in the top part to create a break that allows the package to be opened without separating the permanent seal. This package has a variety of benefits, but suffers in that the equipment required to create the permanent seal is expensive and the process of feeding packages through sealing equipment after filling is time consuming and labor intensive. These issues make it a practical impossibility for many small to medium sized companies to use this type of packaging because they cannot afford to obtain, maintain and operate the necessary sealing equipment.
Accordingly, there is a longfelt and unmet need for a tamper-evident package that is simple and effective, and that can be used by those that cannot afford expensive sealing equipment.
The aforementioned problems are overcome by the present invention wherein a thermoformed clamshell package is provided with a pair of closing flanges and a double-sided adhesive for joining the closing flanges to seal the package. In one embodiment, the package includes a carrier flange that carries the double-sided adhesive prior to sealing and a sealing flange that is brought into contact with the double-sided adhesive to seal the package. In one embodiment, the double-sided adhesive is double-sided tape disposed along the carrier flange of the package. The double-sided tape may have sufficient adhesive strength to make it unlikely for the closing flanges to be separated from one another without causing damage that is evident through visual inspection of the package.
In one embodiment, the closing flanges may include a frangible portion for gaining access to the contents of the package after it has been sealed. The frangible portion may be defined by perforations in one or both of the closing flanges. In one embodiment, the frangible portion is defined by a pair of perforations extending along one of the closing flanges inwardly from the adhesive seal. In this embodiment, the region contained between the perforations may be removed to allow the package to be opened. In another embodiment, perforations may be formed in both closing flanges inwardly from the adhesive seal. In this embodiment, the edge of both closing flanges may be removed together to allow the package to be opened.
In one embodiment, the carrier flange includes a channel for seating the double-sided adhesive. The channel may be of sufficient depth to fully recess the double-sided adhesive. The sealing flange may also include a channel that is configured to fit inside the channel of the carrier flange during sealing.
In one embodiment, the package includes a display strip disposed in the flange region. In one embodiment, the display strip is adhesively secured to a surface of either the carrier flange or the sealing flange. In one embodiment, the package includes two display strips that cooperatively provide hidden content that becomes accessible after the package is opened. For example, a first display strip may be disposed along the frangible portion so that it is removed with the frangible portion. A second display strip may be disposed on the opposite flange. The second display strip may include content on the surface facing the first display strip. In use, the content is hidden when the package is sealed and only becomes visible again when the frangible portion (and consequently the first display strip) is removed.
The present invention also provides method for packaging articles in a package with a tamper-evident seal. The method includes the general steps of: (a) producing a thermoformed package with a carrier flange and a sealing flange, (b) applying a double-sided tape to the carrier flange, (c) removing the release liner from the double-sided tape to expose the free side of the double-sided tape, (d) filling the package with the desired contents and (e) closing the package by bringing the sealing flange into contact with the free side of the double-sided tape. The method may also include the steps of: (a) providing the package with a denesting feature, and (b) nesting the open packages in a shipping container after the release liner has been removed with the denesting features maintaining separation between the exposed double-sided tape and the adjacent nested package. In one embodiment, the step of providing the package with a denesting feature is further defined as forming a channel in the carrier flange and the step of applying the double-sided tape is further defined as applying the double-sided tape to the carrier flange within the channel.
The present invention also provides a method for manufacturing a package with a tamper-evident seal. The method may includes the general steps of: (a) forming a package having an adhesive channel on the sealing flange; (b) providing a double-sided tape with an adhesive portion that is narrower than the channel and a release liner that is wider than the channel; (c) applying the double-sided tape to the carrier flange within the adhesive channel by pressing the double-sided tape into the adhesive channel, wherein the release liner engages the walls of the adhesive channel and is retained outside the channel; and (d) removing the release liner from the double-sided tape. The double-sided tape may be pressed into the channel with a roller having a width substantially lesser than the width of the channel to allow the release liner to bow outside the width of the roller. The method may further include the step of supporting the package on a shoe having an alignment channel that closely receives the adhesive channel to assist in aligning the double-sided tape with the adhesive channel.
The present invention provides a simple and effective tamper-evident seal that can be used without expensive sealing equipment and without specially trained equipment operators. The use of double-sided adhesive allows the package to be securely sealed with minimal effort and limited expertise. The package can be provided with or without a release liner on the double-sided adhesive. When the release liner is removed before the packages are shipped from the manufacturing facility, the packaging of goods can be even easy because the release liner does not need to be removed and there is no need to deal with scrap release liner at the point of packaging. This can be particularly beneficial when packaging fresh fruit and vegetables in the field where dealing with scrap release liner can be particularly burdensome. In applications in which the package will be provided without a release liner, the package can be provided with denesting lugs that help to reduce the possibility of the exposed adhesive causing adjacent packages to stick together. In some applications, the package may include an adhesive channel that can help to protect adjacent packages from sticking together when nested for shipping and storage, and may also be helpful in aligning the double-sided adhesive and package during manufacture.
These and other objects, advantages, and features of the invention will be more fully understood and appreciated by reference to the description of the current embodiment and the drawings.
A thermoformed package in accordance with an embodiment of the present invention is shown in
The illustrated package 10 is designed to hold and display articles at the point of sale. For example, the package 10 is well-suited for use in packaging consumer goods that might benefit from a tamper-evident seal, but do not necessarily require a tamper-proof seal, such as bakery goods, fresh fruits and fresh vegetables. The present invention is not, however, limited to point-of-sale packaging and may instead be used in essentially any packaging application. Although the present invention is described in connection with a clamshell package, it may be incorporated into other types of thermoformed packages. For example, the present invention may be incorporated into a package with separate top and bottom parts. In packages with separate top and bottom parts, at least one edge of the package is sealed by a double-sided adhesive. Any other edges that are to be sealed may be sealed by double-sided adhesive or by other sealing methods, such as RF sealing, ultrasonic welding, heat staking and stitch welding. The package 10 shown in the drawings is merely exemplary and the package can be virtually any desired size and shape depending on the article to be packaged and on aesthetic considerations.
Directional terms, such as “vertical,” “horizontal,” “top,” “bottom,” “upper,” “lower,” “inner,” “inwardly,” “outer” and “outwardly,” are used to assist in describing the invention based on the orientation of the embodiments shown in the illustrations. The use of directional terms should not be interpreted to limit the invention to packages of any specific orientation(s).
As noted above, the illustrated package 10 is a clamshell package having a top part 12 and a bottom part 14 joined along a living hinge 16. The top part 12, bottom part 14 and hinge 16 are integrally formed from a single sheet of the appropriate stock material. The hinge 16 facilitates movement of the package 10 between the open position (See
The top part 12 and the bottom part 14 each include a pocket 26, 28, respectively, and a lip 40, 42, respectively, extending around the periphery of the pocket 26, 28. The hinge 16 may extend from or be part of the lips 40, 42. When the package 10 is pivoted or folded about the hinge 16 into a closed position, the pockets 26, 28 close together cooperatively forming an internal cavity for containing the packaged good(s). The size, shape and configuration of the pockets 26, 28 may vary from application to application. For example, the pockets 26, 28 may be contoured to correspond in shape with the article (or articles) to be packaged. The pockets 26, 28 may be of the same depth or they vary in depth. For example, pocket 28 may be deeper than pocket 26 as shown in
The top part 12 includes a sealing flange 18 that extends outwardly from the lip 40 opposite the hinge 16. The sealing flange 18 may be an extension of the lip 40. Similarly, the bottom part 14 includes a carrier flange 20 that extends outwardly from the lip 42 opposite the hinge 16. The carrier flange 20 may be an extension of the lip 42. The package 10 is configured so that the flanges 18, 20 come together when the package 10 is closed. The size, shape and configuration of the flanges 18, 20 may vary from application to application as desired. In the illustrated embodiment, the flanges have a width of approximately 0.75″, which provides sufficient space for both the double-sided adhesive 22 and the frangible portion 24. As shown, both flanges extend along approximately the full length of the one side of the package 10. The width and length of the flanges 18 may vary from application to application, as desired. Further, the sealing flange and the carrier flange need not be coextensive with one another. Although both flanges 18, 20 are shown as being continuous, one or both of the flanges 18, 20 could be discontinuous, formed by a plurality of flange segments.
The hinge 16 can be any suitable type of connection that allows the top part 12 and bottom part 14 to move with respect to each other. In the illustrated embodiment, the hinge 16 is formed by a series of contours in the material joining the top part 12 and the bottom part 14. The contours are configured so that the hinge 16 undergoes the deformation needed to move the top and bottom parts 12, 14 into closed engagement. If desired, the hinge 16 may be defined by or include a line of weakening in the clamshell material, such as a fold line, a line of reduced thickness or a line of perforations. In other applications, the hinge may be formed by joining together edge portions of separate top and bottom parts (not shown).
As perhaps best shown in
The package 10 includes a frangible portion 24 that that can allow the package 10 to be opened after it has been sealed (See
In this embodiment, the frangible portion 24 is incorporated into the sealing flange 18, and is defined by a pair of perforation lines 46, 48 that extend along the full length of the sealing flange 18. The perforation lines 46, 48 extend generally parallel to one another to create a removable strip of material running across the sealing flange 18. In this embodiment, the perforation lines 46, 48 are spaced roughly 0.24″ apart—although the spacing may vary from application to application as desired. For example, the spacing is typically selected to provide the frangible portion 23 with sufficient width so that it is unlikely to break during removal. Accordingly, the spacing may be dependent on the strength of the sheet stock and the amount of force required to tear the material along the perforation lines. Once removed, the frangible portion 24 of this embodiment separates the top half 12 from the sealed portion of the flanges, thereby allowing the top half 12 to open without breaking the adhesive seal. The perforation lines 46, 48 may be configured to define pull tabs 50, 52 on one or both ends of the removable strip. For example, in the illustrated embodiment, the perforation lines 46, 48 may curve outwardly at opposite ends to form enlarged portions of material that can function as pull tabs. If desired, the pull tabs 50, 52 can be embossed with content, such as printed words (e.g. “PULL”) or other desired graphics. As can be seen in the drawings, the lead in to the pull tabs 50, 52 can be cut to provide clear separation between the tabs 50, 52 and the adjacent flange material. For purposes of this disclosure, the term “perforations” is used to refer to essentially any feature used to weaken the thermoformed material, whether produced during molding or in subsequent processing of the package, including cut score lines, spaced-apart cuts and regions of reduced material thickness. For example, in the illustrated embodiment, each line of perforations includes 0.1466″ cuts spaced apart by 0.012″. The configuration of the perforations may vary from application to application to provide the desired removal force. With thicker sheet stock, it may be desirable to have longer cuts and/or shorter spaces between the cuts. Although frangible portion 24 is disposed on the sealing flange 18, it can alternatively be incorporated into the carrier flange 20 or into both flanges 18, 20 (as described below).
In the illustrated embodiment, the frangible portion 24 is removable from the package 10. In other applications, the frangible portion may provide a single break in the package that separates either the top or bottom part from the sealed regions of the flanges. For example, the sealing flange 18 may include a single perforation line disposed inwardly from the seal. This single perforation line may be broken to separate the sealed portion of the carrier flange 18 from the rest of the top part, thereby allowing the top part to be opened without breaking the seal created by the double-sided adhesive 22. To facilitate use of a single perforation line, a tear strip (not shown) that can be pulled up through the perforation line may be disposed on the bottom of the sealing flange 18 or the top of the carrier flange 20.
The top part 12 and bottom part 14 may be configured to include a releasable closure for selectively maintaining the package 10 in the closed position independently of the double-sided adhesive 22. For example, in the package 10 of
In the illustrated embodiment, the pocket 28 of the bottom part 14 includes a channel 32 that extends around the periphery of the pocket 28 to provide a space to contain a certain amount of juice or other liquids that might run off of the packages goods. For example, in the context of packaging fruit, such as watermelon, it is possible that fruit juice will seep from the packaged fruit. The channel 32 provides an area in which the juice may accumulate so that it is less likely to be in contact with the packaged fruit. Although the illustrated embodiment includes a single continuous channel 32 that extends around the periphery of the bottom part 14, the bottom part 14 may include a network of channels or a plurality of channel segments that collectively provide a place to contain liquids away from the packaged goods.
The package 10 may also include denesting features that help to maintain separation between adjacent packages when the packages are nested for storage and shipping. This optional feature is particularly useful when packages are nested for storage/shipping without a release liner 80 on the upper surface of the double-sided adhesive 22. Without this feature, there is an increased risk that the exposed adhesive on the upper surface of the double-sided adhesive 22 will engage and stick to the bottom surface of the above-stacked package. In the embodiment of
The package 10 may also include a display strip 60 disposed in the flange region. The display strip 60 may provide a visual indication of the removable strip and/or may include advertising content. For example, the display strip 60 may be a highly visible color and may include words or other graphic content that instruct a user on how to open the sealed package 10. In the embodiment of
Referring now to
The double-sided adhesive 22 and display strip(s) 60 may be applied to the flanges in various combinations and configurations. The present invention is intended to encompass essentially any combination and configuration. By way of illustration,
The package 10 of the illustrated embodiment is thermoformed, but packages in accordance with the present invention may be manufactured in other ways, such as injection molding, blow molding, rotational molding and other plastic processing methods. The package 10 is typically constructed from polyvinyl chloride (PVC) or polyethylene terephthalate (PET) or some other polymer, such as high impact polystyrene (HIPS), polycarbonate, acrylonitrile butadiene styrene (ABS) or biodegradable plastics. Although the present invention typically involves the use of thermoplastic polymers, it may alternatively incorporate thermosetting polymers. The package stock is typically transparent, translucent or clear, but the stock may alternatively be opaque, clouded or tinted any suitable color in some applications. The package will vary in thickness from application to application. For standard point-of-sale packaging applications, the package 10 is likely to have a thickness ranging between 12 and 30 gauge (i.e., 12 to 30 thousands of an inch). However, in other applications, the thickness of the material may be outside of that range.
As discussed above, the package 10 may be provided with denesting lugs 70 to maintain the desired separation between adjacent packages during nesting. As an alternative to (or in addition to) the denesting lugs, 70, the package 310 may include channels 376, 378 in the sealing flange 318 and the carrier flange 320, respectively (See
In another aspect, the present invention discloses an apparatus and method for producing a package with double-side tape with the release liner removed from the double-sided tape. More specifically, this aspect of the present invention is directed to an apparatus and method for applying the double-sided tape to the package and removing the release liner. As noted above, it may be a disadvantage in some applications for the package to be provided with the release liner on the double-sided tape. For example, this could result in the need for manual labor at the point of packaging to remove the release liner. It may also produce scrap (i.e. the removed release liner) at the point of packaging that would need to be handled, such as collected and recycled. In this aspect, the present invention provides a tape applicator station 500 that cooperates with features built into the package and the double-sided tape to produce a package in which the release liner is easily removed (See
Referring now to
In the illustrated embodiment, the double-sided adhesive 22 is a double-sided tape that is mounted on a release liner 80 that is wider than the width of the sealing flange channel 378. When the double-sided tape 22 is pushed down into the channel 378, the release liner 80 (which is wider than the channel 378) engages the top surface of the sealing flange 320. This interaction causes the edges of the release liner 80 to stay above the channel and, in some cases, may also cause the release liner 80 to begin to peel away from the double-sided tape 22. The characteristics of the double-sided tape 22, the release liner 80, the roller 504 and the channel 378 are balanced to provide this function and may need to be tuned from application to application. For example, the flexibility of the tape substrate, the adhesive strength of the tape adhesive, the flexibility of the release liner substrate, the characteristics of the release coating of the release liner, the depth and width of the channel, the width of the roller and the downward force applied to the tape by the roller may all be tuned to facilitate this function.
Because the edges of the release liner 80 remain outside the channel 378, the release liner 80 may be more easily removed. For example, the release liner 80 may be removed using automation equipment, such as the suction line 560 shown in phantom lines in
The above description is that of current embodiments of the invention. Various alterations and changes can be made without departing from the spirit and broader aspects of the invention as defined in the appended claims, which are to be interpreted in accordance with the principles of patent law including the doctrine of equivalents. This disclosure is presented for illustrative purposes and should not be interpreted as an exhaustive description of all embodiments of the invention or to limit the scope of the claims to the specific elements illustrated or described in connection with these embodiments. For example, and without limitation, any individual element(s) of the described invention may be replaced by alternative elements that provide substantially similar functionality or otherwise provide adequate operation. This includes, for example, presently known alternative elements, such as those that might be currently known to one skilled in the art, and alternative elements that may be developed in the future, such as those that one skilled in the art might, upon development, recognize as an alternative. Further, the disclosed embodiments include a plurality of features that are described in concert and that might cooperatively provide a collection of benefits. The present invention is not limited to only those embodiments that include all of these features or that provide all of the stated benefits, except to the extent otherwise expressly set forth in the issued claims. Any reference to claim elements in the singular, for example, using the articles “a,” “an,” “the” or “said,” is not to be construed as limiting the element to the singular.
