Tamper-Evident, Tear-Open Resealable Package

Abstract

A tamper-evident package utilizes a transparent resealable adhesive structure such as a tape or a label to cover the portal opening. When the package is first opened, frangible portions of the package between adjacent arcuate cuts and slits that define the portal are torn and distorted so that re-registration of the opposing laterally-extending edges of the portal upon reclosing is not possible. This results in a package which is visually tamper-evident. The tamper-evident condition can be enhanced by graphics or other printing on the front of the package in the area of the arcuate cuts and the center of the portal to make the misalignment of a resealed portal viewed through the transparent reseal structure more visually apparent. In one embodiment of the invention, a series of arcuate cuts are centered laterally and are flanked on the right and left sides by two continuous wavy slits, which together form the portal.

Description

FIELD OF THE INVENTION

The present invention relates to flexible packaging. More specifically it relates to tear-open bags or pouches which have tamper-evident resealable closures.

BACKGROUND OF THE INVENTION

Most often consumer food packages are made in such a way that for the consumer to access the product a tear strip at the top of the pack above the usual zipper or slider has to be torn off and thrown away. Because of the way these packages are made the bag material often tears unreliably and not straight. Sometimes it only tears part of the way and the leftover edges of film get in the way of the zipper or slider reclosing easily. Furthermore, consumers prefer not to be left holding a part of the package in their hands that requires disposal. The construction of these packages requires a heavier, thicker film material which adds to their cost.

While these packages have the advantage of being tamper evident because access can only be made after part of the bag has been permanently destroyed, the noted disadvantages are problems that the packaging industry still faces. Tear-open packages provide a solution because the torn material is visible, but when employed with more desirable lighter weight material they are most susceptible to tearing in unwanted directions. This is especially true when the tear force is initiated from the center of the package front downward which is the preferred opening location and direction.

Resealable packages that are not the tear-open type are not necessarily tamper evident because the parts of the package which are separated upon opening can be repositioned in registration with their original position so that a prior opening is not evident. An example of this construction is shown in U.S. Pat. No. 9,090,383 and is presented here as FIGS. 1 and 2. As seen in these figures a transparent tape 11 seals over a straight lateral opening slit 13. As the tape is pulled away, a package opening 17 occurs along the slit. A portion 15 of the tape 11 wraps around the sides of the package. When resealed the opposing edges of the opening realign so that tampering is not evident.

Other prior art packaging relevant to the present invention includes the following US patent documents: U.S. Pat. Nos. 3,570,751; 4,787,517; 5,746,369; 3,708,108; 2014/0216969; 2008/0240628; 2015/0266626 and 6,659,644.

There is therefore a need in the packaging arts for a resealable tamper-evident package of light weight film that has a central closure which tears open in a controlled, predictable manner and thus avoids the problems of the prior art cited above. It is further desired to devise such a package which is less expensive, easy to manufacture and which functions reliably.

SUMMARY OF THE INVENTION

A package in accordance with preferred embodiments of the invention is described in more detail below. The package solves many of the problems in consumer packaging as discussed above. One embodiment of the invention is a package having a front, a back, and top and bottom edges defining upward and downward longitudinal directions. The direction from one side edge to the other defines a lateral direction.

A tear-open portal having open and closed positions is located along a lateral portal axis “B” for providing access to contents within the package through the portal when in the open position. In a preferred embodiment, the portal comprises two laterally-extending, longitudinally-spaced rows of individual arcuate cuts and frangible portions located between adjacent cuts. Each cut is defined by a continuous arc with an apex and two free ends. A facing direction of each of the cuts is defined by the pointing direction of its apex. The cuts of one row all face in one vertical direction opposite the facing direction of all the cuts of the other row. The rows are longitudinally staggered thereby defining a series of laterally-extending, alternating upward-pointing and then downward-pointing unconnected cuts. In one embodiment, the free ends of the cuts in one row overlap laterally with the free ends in the other row. The free ends of all the cuts may intercept the lateral portal axis “B”.

The package of the invention can be made resealable by using a transparent pressure sensitive adhesive tape or label to cover the portal when closed. When the package is first opened, frangible portions of the package between the adjacent arcuate cuts are torn and distorted so that re-registration of the opposed, laterally-extending edges of the portal is not possible upon resealing. This results in a package which is tamper-evident. The tamper-evident condition can be enhanced by graphics or other printing on the front of the package in the area of the arcuate cuts to make the misalignment of a resealed portal viewed through the tape or label more visually apparent. In one embodiment of the invention, the series of cuts are centered laterally and are flanked on the right and left sides by two continuous wavy slits, which form side portions of the portal. In one preferred embodiment, each of the wavy slits extends laterally to the package side edges along the opening axis from the series of arcuate cuts which occupy the central area of the portal.

The pressure sensitive adhesive tape or label is comprised of a backing and an adhesive on one side of the backing. Tape structures are commonly wound upon themselves placing the adhesive in contact with the reverse or uncoated side of the tape backing or silicone coated release paper and films to enable unwind and dispensing. Tape structures that do not use release liners commonly use differentials in surface energy and or chemical treatment to enable unwind and dispensing into the application. Examples include but are not limited to differentials in surface energy achieved through either flame or corona energy surface treatment or the application of release coatings such as the Escoat Product line of Mayzo Incorporated (Swanee Georgia, USA) based on polyvinyl octadecyl carbamate (PVODC) and polyvinyl stearyl carbamate (PVSC) chemistries. Labels are typically comprised of a silicone release liner which could be either filmic or paper, a working pressure sensitive adhesive surface which as adhered to a backing substrate, a backing film or paper and optionally a topcoat or surface treatment is applied to the backing on the opposite side of the pressure sensitive adhesive to enable printing and other similar finishing steps.

The backing material used in accordance with the inventive tamper evident reseal system comprises any known backing materials that are capable of being blown or cast into a transparent or semi-transparent continuous film. The backing material is substantially a two-dimensional object having a first and second side. By substantially two-dimensional, it is meant an object having a significantly large size measurement in two dimensions compared to a significantly small size measurement in the third dimension. Some particularly suitable backing materials include polymers, including, but not limited to polyethylene terephthalate, polyethylene, polypropylene; copolymers such as poly ethylene-propylene, polyethylene-octene, olefinic block copolymers and poly styrene films. The thickness of the backing will vary according to the particular application. The polymer backing may have a matte or glossy finish as well as a smooth or irregular (e.g., embossed) surface depending on the package it is being applied to. The film backing materials may be prepared utilizing either a single layer or multiple layer comprised of different compositions of the above backing listed polymers. Examples of multi-layer and compositional blends are disclosed in European Patent Number 2 049 333 B1, US Patent 20120060997 A1 and U.S. Pat. No. 5,585,193 A and are hereby incorporated as reference in their entirety as additional suitable backing substrates. Highlighted in U.S. Pat. No. 9,676,532 and in these reference patents are the advantages imparted by Machine Direction Oriented films (MDO) which can be utilized as the backing material for the reseal label structure of this invention. Similarly, as described specifically in the above-referenced patent (U.S. Pat. No. 9,676,532) MDO films could be more advantageous over conventional films in this novel reclose package as the opening feature described below is opened directionally from the reseal label tab in the same machine direction of the film making it less likely to propagate a film tear upon opening and on repeated use in this novel tamper evident resealable package.

The adhesive used in the pressure sensitive coating may comprise any known adhesive. Preferred pressure-sensitive adhesives include formulated hot melt block copolymer adhesives, aqueous acrylic adhesives, solvent acrylic and rubber adhesives, and silicone adhesives. The adhesive can be applied as a continuous layer, or a discontinuous pattern on the backing. When the adhesive is applied as a coating, the coating weight of the adhesive will depend on such factors as the adhesive used, the backing material used, and the end application. Those skilled in the art will readily be able to determine a coating and coat weight.

In accordance with the present invention, the adhesive is generally chosen such that after initial opening at the pull tab location a greater force is required to remove the reseal structure from the package than is required to tear the package along the portal to create the opening to the package contents. In addition, the adhesive must reseal onto the package surface multiple times while not leaving any adhesive residues on the surface of the package to which it is separated from and reapplied to the package. Those skilled in the art will readily be able to determine a suitable pressure sensitive adhesive based on the packaging film and package contents in accordance with the end use application. Suitable examples of pressure sensitive adhesives for use in this novel reclose are disclosed in U.S. Pat. No. 9,676,532 and can be used in both dry and moist package contents. The reseal adhesive does not necessarily have to be resistant to alcohol, but can be depending on the package content.

To best utilize the novel series of arcuate cuts of the invention, a central pull-tab portion at the top of the resealable tape or label is adhesively deadened to facilitate manual grasping by the user so that the covering resealable pressure sensitive tape or label can be pulled downward. Although this grasp point creates radial lines of force on the package front away from the central grasp point, the arcuate cuts transfer these forces more directly to the frangible areas between the cuts so that uncontrollable tearing of the package is avoided. This is not the case with a simple series of linear dotted or dashed slits or perforations. Those types of cuts are only useable when the opening force is applied in the direction of the slits.

By the above package construction, even a light weight, inexpensive, polypropylene material can be used which has been treated with a pressure sensitive adhesive coating. The resealable feature can even be supplied by a simple wrap-around covering resealable transparent adhesive tape which makes the manufacture of the package, usually a flexible pouch or bag, very easy and inexpensive.

It is therefore an object of the invention to devise a tamper-evident package of light weight material that has a central tear-open portal, which tears controllably. Other objects and advantages will be apparent from the following drawings and description of one embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 and 2 are top right front isometric views of prior art packaging;

FIG. 3 is a top right front view of a preconstruction layout of one embodiment of the invention;

FIG. 4 is a close-up view of the tear-open cut pattern;

FIGS. 5 and 6 are top right front isometric views showing a package of the invention before and after the first package opening; and,

FIGS. 7 and 8 are right side sectional views of a package of the invention in the closed and open positions, respectively.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

As defined herein the terms “upward”, “downward” and “longitudinal” define the direction between the top and bottom edges of the package and the terms “lateral” and “laterally” define the direction extending between the opposing sides of the package. Referring now to FIG. 3, a pre-construction layout of the elements of one embodiment of the invention is shown. The film 31 has a piece of transparent, pressure-sensitive-adhesive reseal structure 33 affixed across it extending laterally. The adhesive structure includes a pull tab 35 that projects upward from the main body of the reseal structure 33. The adhesive on the backside of the pull tab 35 is deadened so that it may be easily grasped by the user. The reseal structure 33 extends laterally beyond fold lines 36 which define the sides of the package when constructed so that end portions 34 of the reseal structure 33 wrap around the sides of the package and the side of the structure which is coated with a pressure sensitive adhesive attaches to the back when fully formed for stronger attachment. The reseal structure 33 may be a label or a tape composed of a polymeric backing and a pressure sensitive adhesive on either side of the backing.

Beneath the adhesive reseal structure 33 in the center of the film between the side fold lines 36 a series of slits 37 and cuts 41 define a portal 32, which seals the package's contents when the portal is closed as shown in FIG. 7, and provides access to the package's contents when the portal is opened as shown in FIG. 8. As described in greater detail below, the portal 32 is opened by separating portions of the package front along the slits 37 and cuts 41. The portal 32 comprises right and left side wavy slits 37 and a series of arcuate cuts 41 in the center. For reasons later described, the film preferably has a printed-on graphic such as the word “OPEN” in the area of the arcuate cuts as shown in FIGS. 3, 5 and 6.

FIG. 4 shows the pattern of the series of arcuate cuts 41 that lies in the center of the portal 32 and in the area of the printed word “OPEN”. In a preferred embodiment, the series of cuts 41 comprises two laterally-extending, longitudinally-spaced, opposite facing rows of individual identical arcuate cuts 40, 42. Here we see that each arcuate cut 40, 42 has a facing direction defined by the pointing direction of its apex. The cuts are longitudinally staggered and alternate in upward and then downward pointing directions of their respective apexes. One exemplary longitudinal axis of cut 42 is shown as A-A in FIG. 4. The cuts in the series 41 are substantially identical and are geometrically symmetrical about their axis. Frangible portions 44 of the package front are located between adjacent cuts.

FIGS. 5 and 6 show a package constructed from the layout shown in FIG. 3. FIG. 5 shows the package before the portal 32 has ever been opened, while FIG. 6 shows the package after the portal 32 has been opened and then closed by re-applying the reseal structure 33 over the portal 32. The package has top and bottom edges 51, 52 and a front 75 and a back 76. To open the package for the first time, the user pulls the tab 35 downwardly and away from the package, thereby tearing the package material 44 that resides between adjacent cuts of the centrally located series of arcuate cuts 41. The attachment of the adhesive reseal structure 33 is strengthened by portions 34 which wrap around to the back side of the package 76 as more clearly seen in FIGS. 7 and 8. Other portions of the package front are non-destructively separated along the continuous wavy slits 37 on either side of the arcuate cut series 41. Once opened, the package has the configuration shown in FIG. 8, which provides access to its contents. As shown in FIG. 8, the reseal structure 33 remains adhered to the front 75 of the package along the lower boundary of the portal 32 and the lateral axis B-B.

FIG. 6 shows the package reclosed and resealed. In this configuration, the manually frangible portions 44 of the package are torn apart around and through the printed word “OPEN”. When the reseal structure 33 is reapplied over the portal 32, the word “OPEN” is distorted so that the act of prior package opening is visibly evident through the transparent reseal structure 33. Because only a small portion of the portal needs to be forcibly torn, only a relatively small force is needed. Even without the word “OPEN” or other graphics overlaying the portal, tearing of the frangible portions 44 of the package creates distortion on the front of the package that is visible once the package is resealed by reapplying the reseal structure 33 over the portal 32. As best seen in FIG. 8, distortion is evident at and above the portal 32 where the reseal structure 33 was peeled away from the front 75 of the package. This, in combination with the novel shape of the cuts, permits the desirable use of a lighter gage film material and a package that is easier to open.

The opening process is further depicted in FIGS. 7 and 8. As seen in FIG. 7, the constructed package forms front and back panels 75 and 76. Pull tab 35 has deadening material 71 applied to its back surface to allow manual grasping. With the portal 32 in the closed configuration, the main body of the adhesive structure 33 covers the various closure slits 37 and series of arcuate cuts 41, shown here as cut 73. Side portions 34 of the reseal structure 33 wrap around and are adhered to the back 76 of the package 70. As the tab is grasped and pulled downward the adhesive structure 33 starts to peel from the front panel 75. When the separation point of the peel crosses the above described series of arcuate cuts, the adherence of the reseal structure either a tape or pressure sensitive label to the panel just below the cuts is sufficient to tear the panel material between the cuts 44 to create a package opening through which its contents can be removed. FIG. 8 shows the package of FIGS. 3-7 in its open configuration with the portal moved to the open position. Here we see the material of the package front panel 75 destructively torn apart at the mouth of the opening 77 formed between separated parts of the front panel.

From the above description of the invention it can readily be seen that the objects of the invention have been achieved. While only one embodiment of the invention is depicted in the drawings and described above there can be variations in dimension and proportionality. Furthermore the means of production can be any suitable means available to the art at that time.

Many modifications to the preferred embodiment may be possible without departing from the scope and spirit of the invention which shall be defined only by the following claims and their legal equivalents.

Claims

1. A tamper-evident, resealable package having a front and a back, top and bottom edges, left and right edges, a lateral dimension extending between the side edges, a longitudinal dimension extending between the top and bottom edges, and a laterally-extending, tear-open, reclosable portal moveable from an open position to a closed position for providing access to contents within the package through the portal when open, comprising: a) a series of arcuate cuts through the front of the package comprising laterally-extending, longitudinally-spaced rows of individual, unconnected arcuate cuts, each cut defining a continuous arc with an apex and two free ends;b) laterally-extending slits through the front of the package on either lateral side of said series of arcuate cuts; and,c) a transparent, adhesive reseal structure applied over said portal for holding the portal in the closed position; wherein the package becomes distorted in the area of said arcuate cuts when the package is initially opened to provide visually evidence of prior opening when the package is re-closed with the reseal structure.

2. The package of claim 1, wherein the area above the portal becomes distorted compared to the area below the portal so that re-registration of the areas above and below the portal is not possible upon resealing.

3. The package of claim 1 having manually frangible portions of the package front located between adjacent arcuate cuts which rupture and distort when the package is first opened.

4. The package of claim 1, wherein a facing direction of each of said arcuate cuts is defined by the pointing direction of its apex and wherein the cuts of one row all point in one longitudinal direction opposite the pointing direction of all the arcuate cuts of the other row, said rows being longitudinally staggered thereby defining a series of laterally-extending, alternating upward-pointing and then downward-pointing, unconnected cuts.

5. The package of claim 1, wherein the ends of longitudinally adjacent cuts overlap.

6. The package of claim 1, wherein the ends of said arcuate cuts intercept the lateral closure axis.

7. The package of claim 1, wherein the series of cuts are centered between opposite sides of the package.

8. The package of claim 1, wherein a central, longitudinally-extending tab portion of said reseal structure is adhesively deadened to facilitate its manual grasping.

9. The package of claim 1, further including graphics printed on the front of the package in the area of the series of arcuate cuts to enhance the visual evidence of a prior opening of said portal.

10. The package of claim 1, wherein said adhesive, reseal structure is located across the package front, wraps around the sides of the package, and is adhered to the backs side of the package.

11. The package of claim 1, wherein said arcuate cuts are substantially identical except for their orientation.

12. The package of claim 1, wherein each of said arcuate cuts each has a longitudinal axis, which are parallel to one another.

13. The package of claim 12, wherein each arcuate cut is symmetrical about its longitudinal axis.

14. The package of claim 1, wherein said adhesive, reseal structure comprises either a tape or label having a polymer backing and a pressure-sensitive adhesive on either side of said polymeric backing.

15. The package of claim 1, wherein the pressure-sensitive adhesive is selected such that a greater force is required to remove the reseal structure from the package than is required to tear the package along the portal to create the opening to the package contents.

16. The package of claim 14, wherein the adhesive structure is adapted to function equally well with either moist or dry package contents.