Peelable/resealable package with absorbent strip

The present invention is directed to flexible peelable/reseatable packages uniquely well suited for packaging convenience foods such as processed meats, cheeses and the like. The packages include a peelable/resealable interface formed from a pressure sensitive adhesive (PSA) which permit the packages to be re-sealed after their initial opening. There is also an absorbent non-woven strip which is inserted between the first and second wall panels near the PSA interface. During the opening of the package when the wall panels are forced apart in opposite directions, the absorbent non-woven strip cohesively ruptures and at least a portion of the strip remains bonded to each wall panel after the package has been opened. The absorbent non-woven strip absorbs water and/or fats, grease and oils from the food products before these materials can contaminate the PSA interface.

BACKGROUND OF THE INVENTION

The present invention relates generally to primary packaging and more particularly, to flexible peelable/resealable packages uniquely well suited for packaging convenience foods such as processed meats, cheeses and the like.

Packages which combine an easy-open feature with reclosability provide consumers with a convenient means to open a package without the use of scissors, knives or other cutting implements, and a reliable manner to re-close the package as often as needed. Various methods have been used to provide both these features which include, for example, mechanical strips, such as interlocking fasteners or zippers, and adhesives positioned on an exterior film surface or within the film structure. These methods are known in the art and have been disclosed in U.S. Pat. Nos. 5,063,644; 5,301,394; 5,442,837; 5,445,838; 5,882,789; 5,964,532; 6,409,384; 6,439,770; 6,524,002; 6,527,444; 6,609,827; 6,616,333; 6,632,021; 6,663,283; 6,666,580; 6,679,027; and 7,927,679.

One widely used means of providing package reclosability is to employ zippers compatible with flexible packages of plastic film construction. Product packaging having zipper reclose mechanisms are often employed for packaging products in situations where the consumer may wish to remove only a portion of the product and to reclose the package. One problem with such zippers is that application of zippers to a film roll makes the film roll bulky and more difficult to handle. Although packaging zippers can be applied in high speed in-line form-fill-seal operations, the equipment requirements for application of zippers and the expense of the zipper materials can be significant. While mechanical closures can be applied in form-fill-seal operations, it often requires complex manufacturing steps to apply, interconnect, and align the mechanical fastening features of each structure. Therefore, mechanical reclosable fasteners often add undue complexity, cost, and expense into the flexible packaging manufacture. In addition, zippers may not provide hermetic seals when desired. Also, some consumers have difficulty operating and manipulating zipper closures.

One method of providing easy-open and reclosability to a package which can be hermetically sealed is the use of films or film laminates having a layer of pressure sensitive adhesive (PSA). The consumer may readily open the package by cohesively rupturing the PSA layer and reseal the package along the exposed PSA interface. When the package is opened in this manner, PSA is exposed on the interior surface of each wall of the package. However, care must be taken to prevent contamination of the PSA by the contents of the package. Any matter or debris failing onto the exposed PSA surface can reduce the re tack adhesion at of the PSA interface.

A particular challenging problem encountered with packages having an exposed PSA interface is contamination of the adhesive by water and/or fats, grease and oils from processed meat and cheese products. During the manufacture of such products, significant amounts of water and/or fat may be added to the food product mixture. With some processed meat products such as sliced luncheon meats, as much as 35% to 75% by weight of the total product is water and at least 5% by weight animal or vegetable fat. When the consumer opens the package and removes an individual slice of meat or cheese, the product typically contacts the exposed PSA interface as it is drawn out of the package. Water and/or grease can be absorbed by the adhesive and/or react with the adhesive components. These interactions can often change the adhesive properties of the adhesive which then affect the resealability performance of the package. Eventually, with repeated water/grease interactions, the reseal integrity of the package may be lost. Those skilled in the art have recognized this as a potential weakness of peelable/resealable PSA interfaces in re-closable packages for processed meat and cheese products.

Accordingly, a solution to this long-felt but hitherto unresolved problem is desired which is simple and economical yet reliable, and durable.

SUMMARY OF THE INVENTION

The present invention is directed to peelable/resealable packages having particular application for packaging of processed foods, such as, but not limited to luncheon meats and cheeses. The packaging of the present invention includes a top end and a bottom end generally opposite the top end, a first side edge and a second side edge generally opposite the first side edge. These packages further include a first wall panel having an interior surface and an exterior surface, a second wall panel having an interior surface and an exterior surface, a first side heat seal located adjacent to the first side edge which extends from the top end to the bottom end, and a second side heat seal located adjacent to the second side edge which extends from the top end to the bottom end.

One important aspect of the packages of the present invention is that they include an absorbent non-woven strip located generally near the top end which is inserted between the first and second wall panels. The absorbent non-woven strip may be adhesively adhered or heat sealed to each wall panel or adhesively attached to one wall panel and heat sealed to the other wall panel. The absorbent non-woven strip may include, but is not limited to any paper-based material, cellulose material or non-woven cellulose-base and synthetic fibers or combinations thereof which are capable of absorbing water and/or grease, oil or fat. The absorbent non-woven strip is bonded to each wall panel such that the adhesion between the strip and each wall panel is greater than the cohesive strength of the non-woven strip material. During the opening of the package when the wall panels are forced apart in opposite directions, the absorbent non-woven strip cohesively ruptures and at least a portion of the strip remains bonded to each wall panel after the package has been opened. In one preferred embodiment, the absorbent non-woven strip includes a mono-layer of absorbent material which can be heat sealed between two film layers or two wall panels of the package. In another preferred embodiment, the absorbent non-woven strip includes at least two layers: a first layer comprising, an absorbent material and a second layer comprising a heat sealable material. In another preferred embodiment, the absorbent non-woven strip includes three layers: an exterior first layer comprising pressure sensitive adhesive (PSA), an interior second layer comprising an absorbent material, and an exterior third layer comprising pressure sensitive adhesive (PSA). Alternatively, the absorbent non-woven strip may include an exterior first layer comprising a heat sealable material, an interior second layer comprising an absorbent material, and an exterior third layer comprising a heat sealable material. In still another preferred embodiment, the absorbent non-woven strip includes at least four layers: an exterior first layer comprising heat sealable material, an interior second layer comprising an absorbent material, an interior third layer comprising an oriented thermoplastic material, and an exterior fourth layer of pressure sensitive adhesive (PSA). In yet another preferred embodiment, the absorbent non-woven strip comprises an exterior first layer of non-woven absorbent material, an interior second layer comprising a polyolefin, an interior third layer comprising an oriented thermoplastic material, and an exterior fourth layer of pressure sensitive adhesive (PSA).

Another important aspect of the packages of the present invention is that they have an initial closed position comprising a first peelable/resealable transverse heat seal located generally near the top end and extending between the first side edge and the second side edge which joins the interior surface of the first wall panel to the interior surface of the second wall panel. The first peelable/resealable transverse heat seal will include a cross-sectional portion of the first wall portion having an integrally formed pressure sensitive adhesive (PSA) film layer or a cross-sectional portion of the package having an inserted pressure sensitive adhesive (PSA) strip. In one preferred embodiment, the first peelable/resealable transverse heat seal is placed superimposed laterally over the integrally formed pressure sensitive adhesive (PSA) film layer or inserted pressure sensitive adhesive (PSA) strip. The first peelable/resealable transverse heat seal is positioned such that the cross-sectional area of the wall panel under the heat seal includes at least part of the non-woven absorbent strip and either the integrally formed pressure sensitive adhesive (PSA) film layer or the inserted pressure sensitive adhesive (PSA) strip. Alternatively, in another preferred embodiment, the first peelable/resealable transverse heat seal is placed offset laterally between the non-woven absorbent strip and the top end. In this offset position, the first peelable/resealable transverse heat seal will include either a cross-sectional portion of the first wall portion having an integrally formed pressure sensitive adhesive (PSA) film layer or a cross-sectional portion of the package having an inserted pressure sensitive adhesive (PSA) strip.

In another preferred embodiment, the packages of the present invention may further include a second peelable/resealable transverse heat seal placed below the non-woven absorbent strip and the first peelable/resealable transverse heat seal. The second peelable/resealable transverse heat seal extends between the first side edge and the second side edge and joins the interior surface of the first wall panel to the interior surface of the second wall panel.

Another important aspect of the packages of the present invention is that they include an open position where the first wall panel and the second wall panel are separated at the first peelable/resealable transverse heat seal. This open position comprises an exposed first section of the interior surface of the first wall panel comprising pressure sensitive adhesive (PSA), an exposed second section of the interior surface of the first wall panel comprising the non-woven absorbent material, an exposed first section of the interior surface of the second wall panel comprising pressure sensitive adhesive (PSA), and an exposed second section of the interior surface of the second wall panel comprising the non-woven absorbent material. In one preferred embodiment, the exposed sections of pressure sensitive adhesive (PSA) and non-woven absorbent material on each wall panel are adjacent to each other. In another preferred embodiment, the exposed sections of pressure sensitive adhesive (PSA) and non-woven absorbent material on each wall panel are offset away from each other.

As used herein, the terms “heat seal” and the like refer to a first portion of a film surface (i.e., formed from a single layer or multiple layers) which is capable of forming a hermetic fusion bond to a second portion of a film surface typically under heat and pressure. A heat-seal layer is capable of fusion bonding by conventional indirect heating means which generate sufficient heat on at least one film contact surface for conduction to the contiguous film contact surface and formation of a bond interface therebetween without loss of the film integrity. It should be recognized that heat sealing can be performed by any one or more of a wide variety of manners, such as using a heat seal technique (e.g., melt-bead sealing, thermal sealing, impulse sealing, ultrasonic sealing, hot air, hot wire, infrared radiation, etc.).

Packages of the present invention incorporate a seal area having a peelable/resealable film interface which provide an easy means to both open the package without having to tear the packaging material and re-close the package as often as needed. In general, these peelable/resealable film interfaces are formed when two film surfaces are bonded or sealed together during the package fabrication process. This seal area or bond is considered “peelable” if the consumer simply grasps a portion of the wall panel and pulls or “peels” it away from a second wall panel. The initial force needed to separate the wall panels is relatively strong before the package is opened in order for the seal area to withstand the expected abuse during the packaging operation, distribution, and storage. By contrast, after the package has been initially opened, the peeling force required to break the seal and re-open the package is relatively weak thereafter. Moreover, the package is considered “resealable” if the consumer simply engages the two wall panel surfaces together. Generally, the force required to affect either an adhesive or a cohesive failure between wall panel surfaces may be measured by its “peel strength” in accordance with ASTM F-904 test methods. A peelable package structure is adapted to remain secure and unbroken during package fabrication, distribution and storage, and yet may be relatively easily ruptured. Accordingly, a peelable package structure may include a frangible layer such as a pressure sensitive adhesive having a peel strength of between 500 gram-force/inch (87.6 Newton/meter) and 5000 gram-force/inch (875.5 Newton/meter) as measured in accordance with ASTM F-904 test method. As used herein, the term “resealable” refers to an interface adapted to re-adhere to itself after separation. The force required to “reseal” these pressure sensitive adhesive interfaces is proportional to the manual pressure exerted on the film. Consequently, a peelable and resealable pressure sensitive adhesive interface will exhibit a first interfacial peel strength and a second interfacial (or re-tack) peel strength. The peelable, resealable seals which incorporate an pressure sensitive adhesive interface have a first peel strength of between 500 gram-force/inch (87.6 Newton/meter) and 3000 gram-force/inch (525.3 Newton/meter) and a second peel strength of between 350 gram-force/inch (61.3 Newton/meter) and 1000 gram-force/inch (175.1 Newton/meter) as measured in accordance with ASTM F-904 test method. In contrast, a permanent pressure sensitive adhesive interface cannot be readily manually peeled apart and has a peel strength greater than 2500 gram-force/inch (437.8 Newton/meter).

DETAILED DESCRIPTION OF THE INVENTION

Shown inFIGS. 1a-1care preferred embodiments of the flexible peelable/resealable package10of the present invention. Each of these embodiments includes a top end11, an opposing bottom end12, a first side edge13and a second side edge14generally opposite the first side edge, a first wall panel21and a second wall panel22. The first and second wall panels each have an interior surface,21aand22a, and an exterior surface,21band22b, respectively. In one preferred embodiment, the first wall panel and the second wall panel may comprises the same thermoplastic film and each may be rigid or flexible. Alternatively, in another preferred embodiment, the first wall panel may include a rigid or flexible non-thermoformed multilayer thermoplastic film and the second wall panel may include a rigid or flexible thermoformed multilayer thermoplastic film.

It is within the scope of the present invention for the peelable/resealable package to include any number of seals or heat seals as needed for a particular packaging application. In the preferred embodiments of the present invention, there are a first longitudinal side seal71positioned proximal to the first side edge13extending from the top end11to the bottom end12, and a second longitudinal side seal72positioned proximal to the second side edge14extending from the top end to the bottom end. The first and second longitudinal side seals may be formed by a cold seal material or an adhesive material, fusion heat sealing, or a combination of a cold seal material or an adhesive material and fusion heat sealing. In each of these embodiments, the packages further include a transverse end seal73positioned proximal to bottom end12which extends across the package from first side edge13to second side edge14.

The packages of the present invention also include an absorbent non-woven strip62located generally near the top end11which is inserted between the first and second wall panels21and22, and a first peelable/resealable heat seal60(indicated by cross-hatching) also located near top end11of the package which extends from the first side edge13to the second side edge14. Absorbent non-woven strip62may be inserted between the first and second wall panels using an in-line packaging processes similar to that used for inserting conventional zipper closures during the form-fill-seal operation which is well-known in the art. In one embodiment, the absorbent non-woven strip may be a monolayer of paper or cellulose-like material joined to each wall panel by application of heat and pressure such that a portion of the heat sealable material of the interior surfaces21aand22aof the first and second wall panels flows into and becomes intertwined with the fibers of the absorbent non-woven strip. In other embodiments, absorbent non-woven strip62may include one or more heat sealable or adhesive layers to assist with adhering each side of the strip to the wall panels. For example, in one preferred embodiment, the absorbent non-woven strip is a three-layer structure which includes a first heat sealable layer of ethylene vinyl acetate copolymer (EVA) or polyethylene (PE), a central layer of absorbent non-woven cellulose, and a second heat sealable layer of ethylene vinyl acetate copolymer (EVA) or polyethylene (PE). Positioning of the absorbent non-woven strip62in the package is generally near the top end11of the package. In one preferred embodiment, the inserted absorbent non-woven strip62is disposed adjacent to the inserted pressure sensitive adhesive (PSA) strip61as shown inFIGS. 2aand 3a. In another preferred embodiment, the inserted absorbent non-woven strip62is disposed laterally offset away from the inserted pressure sensitive adhesive (PSA) strip61as illustrated inFIGS. 2band3b.

As shown in the preferred embodiments ofFIGS. 1a, 1b, 1c, 2a, 2band 2c, the packages have an initial closed position comprising a first peelable/resealable transverse heat seal50located generally near the top end11and extending between the first side edge13and the second side edge14which joins the interior surface21aof the first wall panel21to the interior surface22aof the second wall panel22.FIGS. 2aand 2cillustrate preferred embodiments of the present invention with the first peelable/resealable transverse heat seal50placed superimposed over the non-woven absorbent strip62. WhileFIG. 2bdepicts another preferred embodiment of the present invention with the first peelable/resealable transverse heat seal50positioned laterally offset between the non-woven absorbent strip62and the top end11.FIG. 2balso illustrates a package according to the present invention having a second peelable/resealable transverse heat seal51which is positioned laterally offset away from non-woven absorbent strip62and first peelable/resealable transverse heat seal50.

The packages of the present invention are designed such that when a consumer wishes to access the contents of the packages of the present invention, the unsealed portions of the first and second wall panels above the first peelable/resealable transverse heat seal50may be grasped and the wall panels pulled away from each other, rupturing the pressure sensitive adhesive layer which thereby creates an open position where the wall panels are separated proximal to the top end of the package as indicated inFIGS. 3aand 3b. This open position comprises sections of the interior surface21aof the first wall panel21comprising exposed pressure sensitive adhesive (PSA)61aand exposed non-woven absorbent material62a, and sections of the interior surface22aof the second wall panel22comprising exposed pressure sensitive adhesive (PSA)61band exposed non-woven absorbent material62b. It should be noted that the exposed sections of pressure sensitive adhesive (PSA)61aand61bmay be formed from an integrally formed pressure sensitive adhesive (PSA) film layer of a multilayer film used to create first wall panel21or a pressure sensitive adhesive (PSA) strip inserted between first wall panel21and second wall panel22. It should also be noted here that integrally formed pressure sensitive adhesive (PSA) film layer or pressure sensitive adhesive (PSA) strip was vertically aligned underneath the peelable/resealable transverse heat seal50. During the opening of the package when the wall panels are forced apart in opposite directions at peelable/resealable transverse heat seal50, the pressure sensitive adhesive (PSA) layer61and absorbent non-woven strip62both cohesively rupture and at least a portion of each, i.e., pressure sensitive adhesive (PSA) sections61aand61band absorbent non-woven strip62aand62bsections remain bonded to each wall panel after the package has been opened. These exposed sections absorbent non-woven strip62aand62bare thus positioned to absorb water and/or fats, grease and oils from the food products before these materials can contaminate the exposed pressure sensitive adhesive (PSA) sections61aand61b.

When the consumer wishes to re-close the package after its initial opening depicted inFIGS. 3aand 3b, the exposed pressure sensitive adhesive (PSA) sections61aand61bmay be pressed together to re-seal the adhesive interface. This creates second closed position comprising an adhesive seal between the first and second wall panels at the pressure sensitive adhesive (PSA) interface. Thus, it should be evident to those skilled in the art that the packages of the present invention are peelable and resealable.

Film Examples

Referring now toFIG. 4, there is illustrated preferred embodiments of a multilayer thermoplastic film1000suitable for use as a first wall panel21, a multilayer thermoplastic film2000suitable for use as an inserted pressure sensitive adhesive (PSA) strip61, an inserted multilayer film3000suitable for use as a non-woven absorbent strip62, and a multilayer thermoplastic film4000suitable for use as a second wall panel22in the construction of the present invention. In this embodiment, film1000was produced using blown film coextrusion techniques and equipment which is well-known in the art. Film1000may have any number film layers and film layer compositions as desired depending upon the particular packaging requirements for a given product. In this example, a first wall panel21was formed from film1000having an exterior abuse first layer1001which may comprise any conventional abuse material known in the art such as, but not limited to, oriented polyethylene terephthalate (OPET), nylon, biaxially oriented nylon (BON), polypropylene and biaxially oriented polypropylene (BOPP), a permanent adhesive second layer1002such as, but not limited to, any conventional polyurethane-based adhesive, a polyolefin third layer1003such as, but not limited to, polyethylene (PE), ethylene vinyl acetate copolymer (EVA) and combinations thereof, a conventional tie material fourth layer1004such as, but not limited to, polyolefins, anhydride-modified polyolefins and mixtures thereof, an oxygen barrier fifth layer1005, which may comprise any conventional oxygen gas barrier material such as, but not limited to, ethylene vinyl alcohol copolymer (EVOH) and nylon, another conventional tie material sixth layer1006, and finally another exterior seventh layer1007which may comprise a heat sealable polyolefin such as, but not limited to polyethylene (PE), ethylene vinyl acetate copolymer (EVA) and mixtures thereof. Seventh layer1007should be heat sealable to at least one of layers2001and2013of film2000, layers3001and3003of film3000, and layer4001of film4000. The total thickness of film1000is generally from about 19.1 μm (0.75 mil) to about 254 μm (10 mil), most typically about 63.5 μm (2.5 mil).

Multilayer film2000may have any number film layers with the proviso that there is at least one layer of pressure sensitive adhesive which can cohesively delaminate from itself. In this particular example, an inserted pressure sensitive adhesive (PSA) strip61is formed from a multilayer film2000having a first layer2001which is an exterior layer comprising a material which is heat sealable to at least one of layer1007of film1000or layer4001of film4000. As such, layer2001may comprise a polyolefin such as, but not limited to polyethylene (PE), ethylene vinyl acetate copolymer (EVA) and mixtures thereof. Film2000also includes a second layer2002which is a tie layer that may include any conventional tie material such as, but not limited to, polyolefins, anhydride-modified polyolefins and mixtures thereof, a third layer2003which may include nylon such as, but not limited to, nylon 6 and blends thereof, a fourth layer2004which may comprise any conventional oxygen gas barrier material such as, but not limited to, ethylene vinyl alcohol copolymer (EVOH) and nylon, a fifth layer2005which is another nylon layer that may include nylon 6 and blends thereof, a sixth layer2006which is a tie layer comprising any conventional tie material such as, but not limited to, polyolefins, anhydride-modified polyolefins and mixtures thereof, finally, a seventh layer2007comprising any heat sealable material such as, but not limited to polyethylene (PE), ethylene vinyl acetate copolymer (EVA) and mixtures thereof, eighth layer2008comprising any heat sealable material such as, but not limited to polyethylene (PE), ethylene vinyl acetate copolymer (EVA) and mixtures thereof, a ninth layer2009which is a tie layer comprising any conventional tie material such as, but not limited to, polyolefins, anhydride-modified polyolefins and mixtures thereof, a tenth layer2010may comprise any conventional oxygen gas barrier material such as, but not limited to, ethylene vinyl alcohol copolymer (EVOH) and nylon, an eleventh layer2011that may include any conventional tie material such as, but not limited to, polyolefins, anhydride-modified polyolefins and mixtures thereof, a twelfth layer2012which is a layer comprising a pressure sensitive adhesive (PSA), and finally, a thirteenth layer2013which is an exterior layer comprising any heat sealable material such as, but not limited to polyethylene (PE), ethylene vinyl acetate copolymer (EVA) and mixtures thereof which is heat sealable to either layer1007of film1000or layer4001of film4000. The total thickness of film1000is generally from about 19.1 μm (0.75 mil) to about 254 μm (10 mil), most typically about 127 μm (5 mil).

In this particular embodiment, an absorbent non-woven strip62is formed from a multilayer film3000which includes a first exterior layer3001which may comprise any heat sealable material such as, but not limited to, polyethylene (PE), ethylene vinyl acetate copolymers (EVA) and combinations thereof, a central layer3002comprising any conventional non-woven cellulose material, and a second exterior layer3003which may comprise any heat sealable material such as, but not limited to, polyethylene (PE), ethylene vinyl acetate copolymers (EVA) and combinations thereof. Layers3001and3003are heat sealable to at least one of layer1007of film1000or layer4001of film4000.

The second wall panel22was formed from a second multilayer film4000. Film4000may have any number of layers and film layer compositions as desired depending upon the packaging requirements of a given product. In this example, film4000has a first layer4001is an exterior layer comprising any heat sealable material such as, but not limited to polyethylene (PE), ethylene vinyl acetate copolymer (EVA) and mixtures thereof which is heat sealable to at least one of layer1007of film1000, layers2001and2013of film2000, and layer3001and3003of film3000. Film4000also includes a second layer4002comprising any conventional tie material such as, but not limited to, polyolefins, anhydride-modified polyolefins and mixtures thereof, a third layer4003which may include any nylon such as, but not limited to, nylon 6 and blends thereof, a fourth layer4004which includes any conventional oxygen gas barrier material such as, but not limited to, ethylene vinyl alcohol copolymer (EVOH) and nylon, a fifth layer4005which is another nylon layer comprising nylon 6 and blends thereof, a sixth layer4006comprising any conventional tie material such as, but not limited to, polyolefins, anhydride-modified polyolefins and mixtures thereof, and finally, a seventh layer4007which is an exterior abuse layer comprising any conventional abuse material known in the art such as, but not limited to, oriented polyethylene terephthalate (OPET), nylon and biaxially oriented nylon (BON) polypropylene and biaxially oriented polypropylene (BOPP).

Referring now toFIG. 5, there is illustrated an alternative preferred embodiment of a multilayer thermoplastic film5000which is suitable as a first wall panel21having an integrally formed pressure sensitive adhesive (PSA) film layer. As is illustrated, multilayer films3000and4000as described above are used as the inserted non-woven absorbent strip62and the second wall panel22, respectively, in combination with multilayer film5000to construct the packages of the present invention. Film5000was produced using blown film coextrusion techniques and equipment which is well-known in the art and may have any number layers and layer compositions as desired depending upon the packaging requirements of a given product. In this particular example, film5000includes an exterior abuse first layer5001which may comprise any conventional abuse material known in the art such as, but not limited to, oriented polyethylene terephthalate (OPET), nylon, biaxially oriented nylon (BON), polypropylene and biaxially oriented polypropylene (BOPP), a permanent adhesive second layer5002such as, but not limited to, any conventional polyurethane-based adhesive, a polyolefin third layer5003such as, but not limited to, polyethylene (PE), ethylene vinyl acetate copolymer (EVA) and combinations thereof, a conventional tie material fourth layer5004such as, but not limited to, polyolefins, anhydride-modified polyolefins and mixtures thereof, an oxygen barrier fifth layer5005, which may comprise any conventional oxygen gas barrier material such as, but not limited to, ethylene vinyl alcohol copolymer (EVOH) and nylon, a sixth layer5006which is a tie layer comprising any conventional tie material such as, but not limited to, polyolefins, anhydride-modified polyolefins and mixtures thereof, finally, a seventh layer5007comprising any pressure sensitive adhesive (PSA), and an eighth layer5008which is an exterior layer comprising any heat sealable material such as, but not limited to polyethylene (PE), ethylene vinyl acetate copolymer (EVA) and mixtures thereof which is heat sealable to at least one of layers3001or3003and layer4001of film4000. The total thickness of film5000is generally from about 19.1 μm (0.75 mil) to about 254 μm (10 mil), most typically about 101.6 μm (4 mil).

The above description and examples illustrate certain embodiments of the present invention and are not to be interpreted as limiting. Selection of particular embodiments, combinations thereof, modifications, and adaptations of the various embodiments, conditions and parameters normally encountered in the art will be apparent to those skilled in the art and are deemed to be within the spirit and scope of the present invention.