EP2969834A1 - Sheet material capable of being formed into a resealable package - Google Patents

Abstract

A package includes a sheet of flexible material that has a first configuration of a generally flat configuration and a second configuration of a folded and sealed configuration. In the flat configuration, both prior to and after sealing, a user can utilize the sheet as a working surface. The flexible material includes a foldable portion and sealing areas disposed on first and second package portions on opposite sides of the foldable portion. When a sealed package is desired, a user can fold the sheet generally about the foldable portion so that the sealing areas generally align with one another. The user can then compress the aligned and abutting sealing areas to ensure sealing. To access the sealed contents, a user can simply pull the folded flexible material portions generally apart from one another to separate the engaged sealing areas.

Description

SHEET MATERIAL CAPABLE OF BEING FORMED

INTO A RESEALABLE PACKAGE

Cross-Reference to Related Applications

[0001] This application claims the benefit of U.S. 61/794,029, filed March 15, 2013, which is hereby incorporated by reference herein in its entirety.

Field

[0002] This application relates generally to sheet material capable of being formed into flexible packaging, and more particularly to sheet material capable of being folded into resealable flexible packaging.

Background

[0003] One type of package known in the art is a pouch or bag, which is generally constructed of a flexible plastic or film. The package of this type is generally rectangular and sealed on three sides, so that the package has an open mouth to provide access to the interior of the package. In one form, the package uses a flap of material extending from one side of the mouth and a pouch on the other side of the mouth to receive the flap for closure, similar to an envelope. In another form, the package includes a slider or press-to-close zipper closure across the mouth that is configured to seal the package.

[0004] While satisfactory for many purposes, these packages can be difficult to load with contents, such as sandwiches, that are large and unwieldy relative to the mouth. This is especially true for contents that are messy or sloppy. In one illustrative example, to store a peanut butter and jelly sandwich, a user has to create the sandwich and then load the sandwich into the package. In order to keep the sandwich together, a user grips the sandwich on both sides and reaches into the package to place the sandwich therein. If the sandwich leaks out of one of its sides, the peanut butter and/or jelly can smear across the inside of the package or around the mouth, causing an undesirable mess. Summary

[0005] A package including a sheet of flexible material is disclosed herein that has a first configuration of a generally flat configuration and a second configuration of a folded and sealed configuration. In the flat configuration, both prior to and after use, a user can use the sheet to prepare contents, as a working surface, or a placemat. Then, when a sealed package is desired, the user can fold the sheet about desired contents to seal the contents therein. Advantageously, the flexible material includes a foldable portion or fold line, whether pre-crimped, marked by indicia, or imaginary, and sealing areas disposed on opposite sides of the fold line. Thus, when the sealed package of the folded configuration is desired, a user can fold the sheet generally about the foldable portion so that the sealing areas generally align with one another. The user can then compress the aligned and abutting sealing areas to ensure sealing. To access the sealed contents, a user can simply pull the folded flexible material portions generally apart from one another to separate the sealing areas. The user can then advantageously lay the sheet flat after opening for a working surface or placemat.

[0006] In a first form, a package includes a sheet of flexible material that includes edges, an interior face, and an exterior face. A foldable portion is disposed across the sheet between the edges and divides the sheet into first and second flexible panels. Cohesive strips are disposed on the interior face of the sheet along the side edges thereof and end cohesive strips are disposed on the interior face of the sheet along the edges thereof. The cohesive strips include first and second cohesive opposing strip portions disposed on the first and second panels respectively which are configured to respectively align and be engaged to form a sealed package in response to the first and second flexible panels of the sheet being folded together about the foldable portion. The package further includes one or more opposed unsealed outer edge flaps of the interior faces of the folded sheet disposed along each side of the sealed package between the edges of the sheet and the cohesive strips, the opposed unsealed outer edge flaps being configured to be gripped and pulled apart to separate the first and second cohesive strip portions to separate the engaged cohesive strips along the edges.

[0007] The package can further include one or more intermediate cohesive strips that extend between at least one of the side cohesive strips and the end cohesive strips. The one or more intermediate cohesive strips are configured sealingly engage and provide a user the ability to divide the sealed package interior into a plurality of sealed package interiors. [0008] In a second form, a package includes a sheet of the flexible material and a low tack cohesive. The sheet has edges and a foldable portion thereacross. The foldable portion divides the sheet into first and second flexible panels and low tack cohesive is disposed on the sheet interior face along edges of the first and second flexible panels. The cohesive is configured to align and be engaged together in response to the first and second panels of the sheet being folded together about the foldable portion. Accordingly, to form a sealed package of the second configuration, the user can fold the sheet about the foldable portion to generally align the low tack cohesive disposed on the first and second flexible panels and compress to seal the sheet about contents therein. The low tack cohesive can have properties and compositions as described herein.

[0009] In a third form, a package includes a sheet of flexible material, complementary coupling components, such as interlocking strips, and a resealable cohesive. The sheet has end edges, side edges, an interior face, and an exterior face. A foldable portion is disposed across the sheet to divide the sheet into first and second panels. In this form, the symmetric sealing areas each include one of the complementary coupling components and resealable cohesive. A first coupling component is mounted to the sheet adjacent to one end edge and a second coupling component is mounted to the sheet adjacent to the other end edge. Thus, the first and second coupling components are on opposite sides of the sheet on either side of the fold line with the sheet in the flat configuration. The resealable cohesive includes opposing side strips disposed on the interior face of the sheet that extend between the first and second coupling components adjacent to side edges of the sheet. Accordingly, to form a sealed package, the user can fold the sheet about the fold line to generally align the first and second mating portions and generally align the resealable cohesive. The package further includes opposed unsealed outer edge flaps of the interior faces of the folded sheet disposed along each side and the end of the sealed package between the side edges and the cohesive strips and the end edges and the coupling components respectively. The opposed unsealed outer edge flaps are configured to be gripped and pulled apart to separate the first and second cohesive strip portions to separate the engaged cohesive strips along the side edges and engaged coupling components along the end edges.

[0010] By another approach, the resealable cohesive of the forms described above can be a low tack cohesive composed as described in greater detail below. The low tack cohesive has a greater affinity for itself than other surfaces or materials. As such, the low tack cohesive in the sealing areas can retain sealing properties even if the cohesive comes into contact with the contents of the package.

Brief Description of the Drawings

[0011] FIG. 1 is a perspective view of a first form of a resealable package with a flexible sheet in a flat configuration with resealable cohesive adjacent to edges thereof;

[0012] FIG. 1A is a perspective view of a second form of a resealable package with a flexible sheet in a flat configuration with resealable cohesive adjacent to edges thereof and intermediate resealable cohesive strips;

[0013] FIG. 2 is a perspective view of the resealable package of FIG. 1 with the sheet in a folded and sealed configuration;

[0014] FIG. 3 is a perspective view of a roll of flexible material separated into sheets for the resealable package of FIG. 1 by frangible portions extending transversely across the flexible material;

[0015] FIG. 4 is a perspective view of a third form of a resealable package with a flexible sheet in a flat configuration with mating closure portions on opposite ends thereof and resealable extending between the closure portions on sides thereof;

[0016] FIG. 4 A is a perspective view of a fourth form of a resealable package with a flexible sheet in a flat configuration with resealable cohesive adjacent to side edges thereof, complementary coupling components adjacent to end edges thereof, and intermediate resealable cohesive strips;

[0017] FIG. 5 is a perspective view of the resealable package of FIG. 4 with the sheet in a folded and sealed configuration;

[0018] FIG. 6 is a perspective view of a fifth form of a resealable package with a flexible sheet in a flat configuration with resealable cohesive adjacent to edges thereof;

[0019] FIG. 7 is a perspective view of the resealable package of FIG. 6 with the sheet in a folded and sealed configuration; and

[0020] FIG. 8 is a perspective view of a roll of flexible material separated into sheets for the resealable package of FIG. 6 by frangible portions extending transversely across the flexible material. Detailed Description

[0021] Generally speaking, pursuant to these various approaches, apparatus and methods as provided herein describe a reclosable package configured for transition between a first, flat and open configuration and a second, folded and sealed configuration, various forms of which are illustrated in FIGS. 1-8. The exemplary forms described herein can advantageously utilize a cohesive, a mating closure, or combinations thereof along outer edges of a web of film to open and close between the first and second configurations.

[0022] Turning now to details of a first exemplary form, as shown in FIGS. 1 and 2. A resealable package 10 includes a sheet 12 shown in the first, generally flattened or laid open configuration. The package of this form utilizes a flexible packaging film or plastic sheet material. The package sheet material can be a flexible single or multi-ply film, sheet, or other material, including such materials as polyethylene terephthalate (PET), polypropylene (PP), which may or may not be single or bi-axially oriented, linear low-density polyethylene (LLDPE), ethylene vinyl alcohol (EVOH), and/or polyethylene (PE) to suggest a few examples. The sheet 12 is separated into a first sheet portion 14 and a second sheet portion 16, in some approaches, by a fold line 18 extending transversely across the sheet 12. In other approaches, the sheet is divided into portions 14, 16 by a foldable area or portion 18. The optional fold line 18 can be pre-crimped into the sheet 12, such as by mechanical folding, scoring, either continuous or broken, and/or can have an indication, such as printing, labeling, or the like, on the sheet 12 so as to clearly display its location. So configured, the package 10 is capable of being folded about the fold line or foldable portion 18 so that the first and second portions 14, 16 are brought into contact with one another or adjacent to one another.

[0023] In one approach, the sheet 12 includes first and second end edges 20, 22 and first and second opposing side edges 24, 26. The first opposing side edges 24 define the side edges of sheet portion 14 and connect to the second opposing side edges 26, which define the side edges of sheet portion 16, at the fold line or foldable portion 18, so that the side edges 24, 26 extend continuously between the end edges 20, 22. It will be appreciated that the exemplary shape shown in the figures provides but one example of the resealable package 10 and sheet 12. Other sizes, shapes, and configurations are also possible.

[0024] In the first illustrated form of FIGS. 1 and 2, the package 10 further includes first and second cohesive zones 28, 30 disposed about a periphery or circumference of the first and second package portions or panels 14, 16, respectively. As discussed herein, the cohesive can be deposited or printed on the sheet 12 in any suitable manner. The first and second cohesive zones 28, 30 are generally symmetrical about the fold line or foldable portion 18 so that the zones 28, 30 generally align as the first and second package portions 14, 16 are pivoted or folded together. More specifically, each of the first and second cohesive zones 28, 30 can include an end cohesive portion 32 extending adjacent to the end edges 20, 22 and opposing side cohesive portions 34 extending adjacent to the first and second opposing side edges 24, 26. In one form, the cohesive zones 28, 30 have a generally uniform width about the periphery of the sheet 12 that is between about 0.25 inch to about 1 inch, and in some approaches about 0.5 inch.

[0025] As shown, the opposing side portions 34 of the first and second cohesive zones 28, 30 connect to one another over the fold line or foldable portion 18 and connect to their respective end cohesive portion 32, so that the first and second cohesive zones 28, 30 provide an unbroken closed cohesive border about a periphery of the sheet 12 and that also provides a generally cohesive-free interior surface 36 that spans across both sheet portions 14, 16. In the flat configuration of FIG. 1, the interior surface 36 can be utilized as a work surface. For example, the interior surface 36 can be used as a staging surface to create a sandwich or the like or be used as a placemat during dining.

[0026] If desired, the cohesive zones 28, 30 can include scalloped edges or broken portions, i.e. strips of non-cohesive, outward portions, so that it is easier to separate the cohesive zones 28, 30 when they are sealed together. These scallops, strips, etc. can extend the length of the cohesive zones 28, 30, be limited to one or both of the side portions 34 or one or both of the end portions 32, select portions thereof, or one or both of the corners connecting the side and end portions 34, 32.

[0027] Although the sheet 12 is shown as generally rectangular and configured to fold into a generally rectangular sealed package, other suitable shapes can be utilized as mentioned above. For example, the sheet 12 can be configured to fold into a triangular sealed package, with corresponding cohesive zones, the sheet can also be generally circular or oval, or other symmetrical shapes.

[0028] So configured, a user can prepare the package contents, if necessary, lay the contents on the interior surface 36 in either the first or second portion thereof. Then, the user can fold the opposite portion about the fold line or foldable portion 18, generally align the first and second cohesive zones 28, 30 and compress the aligned zones 28, 30 to seal the first and second package portions 24, 26 together to form a sealed interior 38 and, thus, form or construct a sealed pouch or package as generally shown in FIG. 2. When the user desires to open the package, the first and second portions 14, 16 can be pulled generally apart at any edge other than the fold 18 to gain access to the contents and/or to use the unfolded interior surface 36 as a placemat or the like.

[0029] In one form, the cohesive zones 28, 30 are spaced from the adjacent edges 20, 22, 24, 26 of the sheet 12 so that there are outward cohesive-free portions, flanges, or flaps 40 about all edges of the sealed pouch or package except the folded edge 18 as shown in FIGS. 1 and 2. These cohesive-free portions 40 provide non-adhered gripping surfaces for a user to grip and separate the first and second cohesive zones 28, 30 when they are sealed together. Advantageously, the user can select any adhered edge to open and the user is not constrained to open a single mouth as in prior flexible packaging. Indeed, the user can even open 2 or more edges at the same time via the portions 40. Alternatively, only the end cohesive portions 32 can be spaced from the end edges 20, 22, or only portions of the end and side cohesive portions 32, 34 can be recessed or have a non-cohesive gripping portion.

[0030] As shown in FIGS. 1 and 2, the first and second package portions 14, 16 are generally symmetrical. This need not be the case, however, as only the first and second cohesive zones 28, 30 are generally symmetrical so that they seal when the first and second portions 14, 16 are folded about the fold line 18. Thus, as shown in FIGS. 6-8, one of the first and second portions can be longer so that there is a more easily grippable and longer flap 40 extending away from the sealed configuration. Moreover, the first and second portions can take a variety of shapes and sizes to provide uniqueness and attract consumer attention. The non-cohesive portions, flaps, or flanges 40 can have any size relative to the width of the cohesive strips or zones 28, 30. In some approaches, the width of the portions 40 range from about 1/16 inch to about 1/4 inch and a ratio of the width of the cohesive 28, 30 to the width of the portions 40 may be about 1 : 1 to about 16: 1. In other approaches, the portions 40 can be up to about 1 inch and the portions 40 can be wider than the cohesive 28, 30.

[0031] As shown in FIG. 1A, an alternative form of sheet 12 is shown which is similar to the sheet of FIG. 1 and, thus, shares the same reference numbers for common components. In this approach, the sheet 12 can further have one or more strips 42 of cohesive disposed on the interior surface 36 and extending between the end cohesive portions 32; one or more symmetric pairs of strips 44 of cohesive/cohesive disposed on the interior surface and extending between the side cohesive portions 34; or any combinations thereof. These strips 42, 44 allow a user to divide the sealed interior 38 into a plurality of smaller sealed interiors 36A by aligning and compressing the desired strips 42, 44 with folding of the sheet 12. This would advantageously allow a user to separately store different contents within the same package within individually sealed area, zones, or pouches. As shown, the strips 42, 44 extend generally perpendicular to each other and the cohesive strips 28, 30, 32; however, these strips 42, 44 may also extend inclined to each other, such as diagonally across the sheet surface 36.

[0032] In a second form shown in FIGS. 4, 4A, and 5, a package 50 is shown having many similarities to the package shown in FIGS. 1, 1A, and 2. Thus, similar reference characters will be utilized for similar features for ease of explanation. The package 50 of this form includes the sheet 12 shown in a generally flattened or laid open configuration. The sheet 12 is separated into the first portion 14 and the second portion 16 by the fold line or foldable portion 18 extending transversely thereacross. As shown, the sheet 12 includes the first and second end edges 20, 22, and the first and second opposing side edges 24, 26. The first opposing side edges 24 connect to the second opposing side edges 26 at the fold line 18, so that the side edges 24, 26 extend between the end edges 20, 22.

[0033] The package 50 of this form includes first and second cohesive zones 52, 54 disposed on the first and second package portions 14, 16, respectively. The first and second cohesive zones 52, 54 are generally symmetrical about the fold line 18 so that the zones 52, 54 generally align as the first and second package portions 14, 16 are pivoted together. More specifically, each of the first and second cohesive zones 52, 54 include opposing side cohesive portions 56 extending adjacent to the first and second opposing side edges 24, 26. In the illustrated form, the cohesive zones 52, 54 have a generally uniform width that is between about 0.25 inch to about 1 inch, and more preferably about 0.5 inch.

[0034] The package 50 further includes first and second non-cohesive complementary coupling components 58, 60 extending adjacent to the package end edges 20, 22 respectively. The non-cohesive coupling components 58, 60 are configured to sealingly mate, couple, or engage when pressed together. In one approach, the non-cohesive coupling components may be tongue and groove, Velcro, snapping, and slider zipper type fasteners to suggest a few. As shown, the opposing side cohesive portions 56 extend between ends 62 of the coupling components 58, 60 and the fold line 18 so that the there is a continuous unbroken length of cohesive between the corresponding ends 62 of the coupling components 58, 60. Then, when the first and second portions 14, 16 are pivoted or folded together about the fold line or foldable portion 18, the first and second cohesive zones 52, 54 and the coupling components 58, 60 align, respectively. A user can then apply compressive pressure on the cohesive zones 52, 54 and coupling components 58, 60, respectively to seal the package into the sealed configuration shown in FIG. 5. By a further approach, the coupling components 58, 60 can be sealed together with the use of a zipper member or the like.

[0035] As shown, the mating members 58, 60 and the first and second cohesive zones 52, 54 connect to provide an unbroken closed sealing border defining an interior surface 64. In the flat configuration, the interior surface 64 can be utilized as a work surface. For example, the interior surface 64 can be used as a staging surface to create a sandwich or the like or a placemat.

[0036] So configured, a user can prepare the package contents, if necessary, lay the contents on the interior surface 64 in either the first or second portion thereof. Then, the user can fold the opposite portion about the fold line 18, generally align the first and second cohesive zones 52, 54 and the mating members 58, 60 and press to seal the first and second package portions 14, 16 together to form a sealed interior 66. Turning to FIG. 4A, the package 50 of this form can further have the one or more optional strips 42 of cohesive disposed on the interior surface and extending between the coupling components 58, 60; the one or more symmetric pairs of optional strips 44 of cohesive disposed on the interior surface and extending between the side cohesive portions 56; or combinations thereof, as shown in FIG. 1 A.

[0037] In one form, the coupling components 58, 60 are spaced from the adjacent end edges 20, 22 of the sheet 12 so that there are gripping surfaces 68 for a user to separate the first and second mating members 58, 60 when they are sealed together. The user can then continue pulling the first and second portions 14, 16 generally away from each other about the fold line 18 to separate the first and second cohesive zones 52, 54. Additionally, the side cohesive portions 56 can be spaced from the side edges 24, 26, or portions of the side cohesive portions 56 can be recessed or have non-cohesive gripping portions 70 to provide a flange, flap, or gripping surface similar to that of FIGS. 1, 1A, and 2.

[0038] As shown in FIGS. 4, 4A, and 5, the first and second package portions 14, 16 are generally symmetrical. This need not be the case, however, as only the first and second cohesive zones 52, 54 and the first and second mating members 58, 60 are generally symmetrical about the fold line 18. Thus, one of the first and second portions can be longer so that there is a more easily grippable flap extending away from the sealed configuration. Moreover, the first and second portions can take a variety of shapes and sizes to provide novelty and attract consumer attention.

[0039] In a further form, the cohesive suitable for the sheets or packages herein can be a low tack cohesive as generally described in U.S. Application Serial Number 13/035,399, which is incorporated by reference herein in its entirety. More details of a particular low tack cohesive are set forth below.

[0040] In one aspect, the low tack cohesive for the cohesive zones 28, 30, 52, 54 and sheet 12 are generally constructed or have a composition to minimize the adhesion of the cohesive to undesired surfaces or foodstuffs and still function at the same time as an effective reclosable fastener. That is, the cohesive has a unique formulation or construction to achieve select tack and peel values so that the cohesive-based fastener can be opened and closed multiple times to seal the contents in the package 10, 50 during use by a consumer, but at the same time not delaminate from the film substrate forming the opposing inner surfaces of the sheet 12.

[0041] To this end, the cohesive can be a UV-cured cohesive with relatively low tack levels to minimize adhesion to the unwanted surfaces, a selected bonding or opening peel strength sufficient to enable secure reclosure of the package 10, 50, and a peel strength robust enough to enable repeated opening and reclosing of the package 10, 50. At the same time, the cohesive also has a strong bond to the film substrate of the sheet 12 so that the cohesive does not delaminate upon opening of the package 10, 50. By one approach, the cohesive may include specific blends of a UV-curable acrylic oligomer and a tack control agent. In other approaches, the cohesive may include specific blends of the UV-curable acrylic oligomer, the tack control agent, and an elastomer (rubber) component.

[0042] Preferably, the cohesive is a UV-cured pressure sensitive cohesive (PSA) exhibiting cohesive properties and low tack, but, despite the low tack, still forms a strong bond to the film substrate forming the opposing inner surfaces of the sheet 12. As generally understood, a cohesive-based material typically adheres more readily to like materials (i.e., self-adhesion) rather than to non-like materials. Suitable cohesive materials used herein generally exhibit a relatively low tack to undesired surfaces, but at the same time still exhibit a good bond strength to desired surfaces (such as no delaminating from the flexible front and back panels), and relatively good cohesive or self adhesion bond strength to like surfaces to hold a flexible package or pouch closed, but still permit the package to be openable or peelable by hand. The selected cohesive-based materials also permit debonding or peeling from such like materials so that the cohesive layers may be repeatedly peeled apart without substantial damage to the cohesive material and/or any underlying substrate. When the cohesive material is debonded or peeled apart, the selected cohesive materials has sufficient internal integrity and generally peels apart at an cohesive bonding interface substantially cleanly without substantial material picking, stringiness, delamination from the substrate, and/or other substantial disfigurations of the material (i.e., globbing, pilling, etc.). Advantageously, the cohesive -based fasteners herein maintain a peel adhesion where opposing cohesive strips contact each other with an average initial peel adhesion greater than about 80 grams per linear inch (gpli) and, preferably, between about 80 and about 900 gpli. Moreover, in some instances, the cohesive-based fasteners 14 retain greater than about 80 gpli and/or at least about 30 to about 200% of the average initial peel adhesion after five repeated seal and unseal operations.

[0043] In another aspect, the package 10, 50 and cohesive are also constructed to interact with each other so that the bond or peel strength of the cohesive to the inner surface of the sheet 12 is generally greater than the opening peel strength between the layers of the cohesive itself. In this manner, the cohesive generally remains adhered to the inner surfaces of the sheet 12 and does not substantially pick, string, or delaminate from the inner surfaces of the sheet 12 when the package 10, 50 is opened by a consumer as the cohesive is peeled open. For example and in one approach, the bond or peel strength of the cohesive to the package film substrate is greater than about 900 gpli and is capable of withstanding multiple peel and re-seal cycles without detachment from the film substrate. In addition, the cohesive is cured so that it is capable of withstanding more than 100 double rubs with methyl ethyl ketone (MEK) solvent (ASTM D5402-06).

[0044] Preferably, the cohesive is UV-cured, and more preferably a UV-cured PSA cohesive exhibiting cohesive properties and low tack, but forms a strong bond to the film substrate of the sheet 12. As generally understood, a cohesive-based material typically adheres more readily to like materials (i.e., self-adhesion) rather than to non-like materials. Suitable cohesive materials used herein generally exhibit a relatively low tack to undesired surfaces, a good bond strength to desired surfaces (such as no delaminating from the flexible first and second panels), and relatively good cohesive or self adhesion bond strength to like surfaces to hold a flexible package or pouch closed, but still openable or peelable by hand. The selected cohesive-based materials also permit debonding or peeling from such like materials so that the cohesive layers may be repeatedly peeled apart without substantial damage to the cohesive material and/or any underlying substrate. When the cohesive material is debonded or peeled apart, the selected cohesive materials has sufficient internal integrity and generally peels apart at a cohesive bonding interface substantially cleanly without substantial material picking, stringiness, delamination from the substrate, and/or other substantial disfigurations of the material (i.e., globbing, pilling, etc.).

[0045] The first component of the cohesive is one or more UV-curable acrylate or acrylic oligomers. For instance, the UV-curable acrylic oligomer may be an acrylic or methacrylic acid ester having multiple reactive or functional groups (i.e., acrylic or methacrylic oligomers). In general, a functional group includes one UV reactive site. UV reactive sites are most commonly carbon-carbon double bonds conjugated to another unsaturated site such as an ester carbonyl group. By one approach, the UV-curable acrylic oligomer is an acrylic or methacrylic acid ester of a multifunctional alcohol, which means the oligomer has more than one acrylated or methacrylated hydroxyl group on a hydrocarbon backbone of the oligomer. By one approach, the cohesive may include about 1 to about 90% by weight of the UV-curable acrylic oligomers and with functionalities of about 1.2 to about 6.0. In another approach, the UV-curable acrylic oligomers may have a functionality of about 2.0 to about 3.0, and/or be provided in the cohesive in an amount of about 20 to about 70% by weight.

[0046] In one form, the multifunctional UV-curable acrylic acid ester is an acrylic acid ester of a vegetable oil having a reactive functionality of 2.0 or greater. In another aspect, the UV-curable acrylic oligomer can comprise an epoxidized soybean oil acrylate. In general, the amount of the UV-curable acrylic oligomers used, based on a preferred cohesive component ratio (ACR) (to be discussed herein), can impact the properties of the final cohesive. For instance, where the amount of the UV-curable acrylic oligomer is too low, based on the preferred ACR, the cure rate of the final cohesive is too slow. On the other hand, where the amount of the UV- curable acrylic oligomer is too high, based on the preferred ACR, the final cohesive may be adequately cured but can have inadequate self adhesion properties to seal and reseal.

[0047] The second component of the cohesive is a tack control agent. By one approach, the cohesive may include about 1 to about 65% by weight of the tack control agent. In another approach, the tack control agent can be present in amounts from about 20 to about 65%. The tack control agent can include a tackifying resin or a curable polymer/monomer combination that when cured can produce the desired levels of tack and self-adhering properties appropriate for the reclosable fastener. In one aspect, the tack control agent can comprise an aliphatic urethane acrylated oligomer. Many other types of tack control agents suitable for UV-curable PSA cohesives may also be used in the reclosable cohesive system.

[0048] An optional third component of the cohesive is an elastomeric or rubber component. By one approach, the elastomeric component may include at least one curable acrylated (i.e., acrylic modified) or methacrylated esters of a hydroxy-terminated elastomeric polymer (i.e., an elastomeric polyol). This elastomeric component can include acrylic-modified polybutadiene, a saturated polybutadiene and/or a flexible polyurethane. In one aspect, a methacrylated polybutadiene can be provided. The elastomeric material can be provided in amounts of about 0 to about 20% when used in the cohesive. In one aspect, the elastomeric material is provided in amounts of about 5 to about 15%>. Satisfactory cohesives can be made with the desired low tack, resealable properties as described herein without the elastomer component; however, it is believed that the elastomeric component aids in achieving an optimal coating performance. The optimal cohesive performance can be defined by properties such as self-adhesion, tack, viscosity, and cure rate, just to name a few. The elastomeric component is useful for adjusting peel strength properties, substrate adhesion strength, increasing flexibility, viscosity control, and cure rate modulation.

[0049] The average initial peel strength of a properly cured cohesive can be in the range of about 80 gpli to about 900 gpli and, in particular, about 280 gpli to about 800 gpli, as measured by ASTM D3330/D3330M - 04 method F. The cohesive is also designed to retain its average peel after repeated open and close operations (i.e., adhesion retention). Preferably, the cured cohesive can retain its average initial peel adhesion between about 280 and about 800 gpli up to at least five repeated peel-reseal cycles. Preferably, the adhesion retention value upon peeling- resealing-peeling can be between about 30 to about 200% retention of the initial value. Upon contaminating the cohesive with crackers, the adhesion retention value can be between about 30% to about 150% of the initial value, where the cracker contamination test method is as described herein.

[0050] In another approach, at least a portion of the sheet 12, and in some cases an outer layer that contacts the cohesive, may include a polymer coating, layer, filler and/or sealant layer to enhance interfacial bonding between the cohesive and the package substrate of the sheet 12. In one form, the polymer coating may be selected from ethylene vinyl acetate (EVA), a polyolefin (such as polyethylene), or blends thereof. If used, the polymer layer may include the adhesion promoting filler particles. In one form, the filler may be micro- or nano-sized fillers of clay, calcium carbonate, montmorillonite, microcrystalline silica, dolmite, talc, mica, oxides, (silicon oxides, aluminum oxides, titanium oxides, and the like) and other additives and/or combinations thereof, into or onto at least the polymer coating, the first and/or second panels 14, 16, a sealant layer hereon, or a surface layer(s) of the package substrate of the sheet 12 to enhance the bonding of the fastener cohesive to the sheet 12.

[0051] In particular, an organoclay filler may be used, and in one aspect the organoclay filler is organically modified montmorillonite. Organoclay is an organically modified natural clay such as a montmorillonite clay that is processed or treated with surfactants such as quaternary ammonium salts. Montmorillonite is a phyllosilicate group of minerals that typically comprises a hydrated sodium calcium aluminum magnesium silicate hydroxide. While not wishing to be limited by theory, the organoclay-filled substrate can have the ability to aid in producing operable and reclosable cohesive-based closures because the filler helps form a strong bond between the low tack cohesive and the package substrate so that the cohesive does not delaminate from the package substrate of the sheet 12 when the package 10, 50 is opened.

[0052] Effectively dispersing the clay or other filler in polyethylene and EVA that may be used for a sealant layer or other coating of the package substrate of the sheet 12 can be a challenge due to incompatibility of clay fillers and certain polymers. Thus, supplying the filler using a filler composition including the filler blended with a compatible carrier helps aid in the mixing and dispersing of the filler into the sealant layer. By one approach, the clay filler can be supplied in a maleic anhydride grafted linear low density polyethylene carrier (MA-LLDPE) used in the coating or applied to the substrate. While not wishing to be limited by theory, the maleic anhydride portion of the carrier has an affinity for the clay filler and the polyethylene portion of the carrier mixes well with other polymers of the sealant layer. Exemplary clay filler compositions may be obtained from PolyOne Corporation (Avon Lake, Ohio). Without wishing to be bound by theory, it is believed that the organically modified clay particles, which may be highly polar, and/or the maleic anhydride grafted linear low density polyethylene (MA-LLDPE) carrier resin present with the clay fillers serve to promote adhesion of the cured cohesive coating to the substrate surface by increasing the surface energy of the substrate layer.

[0053] Additionally, it is also believed that on a microscopic level the clay or other filler additive(s) may impart surface roughness to the substrate, positively affecting the coefficient of friction of the substrate and increasing the available contact area between the substrate and the coating, thereby providing more sites for chemical and/or mechanical bonding to occur. By one approach, approximately 0.5% to about 20% by weight of the filler composition in the sealant layer is expected to have a beneficial impact on bond strength of the cohesive to the package substrate of the sheet 12 so that the bond to the substrate is greater than the peel adhesion between the cohesive portions such that engaged sealing zones 28, 30, 52, 54 do not delaminate upon opening. Additionally, the filler may roughen the surface of the substrate enabling it to slide freely over metal surfaces of packaging equipment without binding, thus enabling the reduction or elimination of a migratory slip additive in the polymer coating or layer.

[0054] In some instances, an optional component of the polymer layer on the substrate of the sheet 12 can include a migratory slip additive, which helps to decrease coefficient of friction between the substrate and other surfaces, allowing the substrate to slide freely over metal surfaces or itself. In one aspect, an erucamide slip additive (i.e., an unsaturated fatty primary amide) can be provided. Slip additives ranging from 2000 ppm to 7000 ppm have been used; however, it has been discovered that at these high levels it is difficult for the cohesive to bond to the low energy surface of the substrate because the slip additive blocks surface sites where adhesion can take place. However, the addition of the filler allows for a much lower level of the slip additive to be used, such as less than about 1000 ppm. In other cases, the substrate has less than about 700 ppm of the slip additive or in yet other cases no slip additive. Since the use of the filler reduces the coefficient of friction between the substrate and other surfaces, an effect that was previously achieved with addition of the migratory slip additive, this allows for the migratory slip additive concentration to be lowered or eliminated. A lower migratory slip additive level than typically used can also help to increase the bonding of the cured coating to the substrate both initially and over time because there is less of the additive to interfere with the bonding of the coating to the substrate. While not wishing to be limited by theory, it is believed that the fatty acid amides in slip additives, which are low molecular weight components, can migrate or bloom to the surface of the polymer layer affecting the strength of the bond between the sheet 12 and the cohesive. While corona treating or flame treating may initially burn off any fatty acid amides on the surface of the polymer layer resulting in an initial good bond strength of the cohesive. Over time additional fatty acid amides can migrate or bloom to the polymer layer surface, which results in a reduced bond strength over an extended shelf life.

[0055] Additionally, prior to applying the cohesive to the package substrate, in some instances, the substrate can undergo a surface pretreatment to increase the surface energy, and/or application of a primer coat. For example, possible surface treatments may include corona treating, plasma treating, flame treating, and the like or chemical coatings, such as primers or adhesion promoters may also be used. A corona treatment can increase the surface energy of the substrate which improves the coating's ability to bond and remain bonded to the substrate. A corona pretreatment can include a cloud of ions that oxidize the surface and make the surface receptive to the coating. The corona pretreatment basically oxidizes reactive sites on the polymer substrates. If corona treating, ideally the surface energy after treatment should be about 40 dynes or greater.

[0056] Without wishing to be bound by theory, in some cases, it is believed that the corona treatment of the substrate surface helps to provide for a strong bond between the coating layer and the substrate surface due to the increased surface energy of the substrate surface. In addition to the corona treatment, the combination of the pretreatment with a low concentration of a slip additive and the incorporation of a filler composition within the substrate together result in a strong bond between the reclosable fastener and the substrate.

[0057] To achieve the balanced peel, tack, and bond to the package substrate as described herein, it was determined that the amounts of the three cohesive components need to fall within a specific cohesive component ratio (i.e., ACR) of the acrylate oligomer relative to the elastomeric and tack components. Preferably, the ACR for the cohesive is:

(Wt % of acrylate oligomer) = 0.5 to 1.5.

(Wt % of elastomeric material + Wt % of tack control agent)

In a another approach, the ACR can be in the range of about 0.8 to about 1.5. [0058] The range for the ACR of the three components in the formulation has been found to provide a unique cohesive formulation with the low tack property to non-like substances (i.e., machine components, crumbs, particulate, food pieces, and the like), yet can seal to itself with sufficient bond or peel strength to maintain a seal therebetween as well as resist contamination. The cohesive in this specific ACR also provides for a resealable function that does not significantly reduce or lose its seal-peel-reseal qualities upon being subjected to repeated open and close operations. An ACR value below about 0.5 is generally undesired because the cohesive would require significantly large amounts of UV energy to cure. If the ACR is above about 1.5, the cohesive would cure quickly, but it would also have low (or no) peel strength, unacceptable for the cohesive closure herein. In addition to the desired range of the ACR, a satisfactory cohesive formulation in some cases may also have certain other parameters such as mixture-stability of the components, a certain viscosity of the formulation, a certain cure rate, and/or a certain peel strength.

[0059] Not only is the ACR of the cohesive components desired, but the cohesive components must also be compatible with each other such that they form a stable flowable liquid mixture. As used herein, the cohesive is considered stable when it (at a minimum the two or three main components) remains a homogeneous liquid, i.e., there is no visible phase separation of the components and no gel formation, while being held at room temperature (about 70°F- 75 °F) for up to three days.

[0060] In addition, the cohesive formulation can have a viscosity in the range of about 10,000 to about 50,000 centipoise (cPs) or less when at room temperature, or about 2000 cPs or less at about 160°F (7FC) and in some cases about 200 cPs or less at 160°F (71°C). This viscosity range provides for applying the cohesive to a film substrate using conventional printing, roll coating, or slot-die application techniques.

[0061] To produce a sufficiently cured cohesive layer on the substrate, the cohesive can be cured using UV light sources capable of delivering energy in the range of about 100 mJ/cm² to about 800 mJ/cm². This in turn helps to ensure that the cohesive has sufficiently cured as determined by an MEK rub resistance test value (ASTM D5402-06) of about 100 double rubs or more (to be discussed in further detail herein).

[0062] By one alternative approach, the first peel adhesion between the engaged end strips of cohesive 32 is less than the first peel adhesion between the engaged side strips of cohesive 34. For example, the first peel adhesion of the end strips of cohesive 32 can be between about 100 gpli and 200 gpli; and the first peel adhesion of the side strips of cohesive 34 can be between about 300 gpli and about 900 gpli. In other words, the peel adhesion of engaged side strips 34 of cohesive may be about 3 times to about 9 times stronger than the peel adhesion of engaged end strips 32 of cohesive.

[0063] By an alternative approach, by utilizing a low tack cohesive, such as having a composition as discussed above, the first and second cohesive zones can have a wider range than that discussed above, or can cover a majority, or the entirety, of the first and second package portions 14, 16. The low tack properties would allow the sheet 12 to still be used as a work surface because the cohesive would not substantially adhere to the contents of the package 10, 50. For example, completely covering the sheet 12 would enable consumers to customize the size of the sheet 12 and, therefore, the resulting package. This can provide added longevity for perishable contents of the package by better conforming to the contents and minimizing headspace around the contents.

[0064] The low tack can also advantageously be utilized to store the package in a continuous roll 100 of sheets 12, as illustrated in FIGS. 3 and 8. Because the low tack cohesive does not substantially adhere to other surfaces, it tends not to adhere to the exterior surfaces of adjacent sheets 12 in the roll 100, so that sequentially unrolling and removing sheets 12 as needed would not require overcoming the cohesive force of normal cohesives. In one approach, the individual sheets 12 can be separated by a score or perforation pattern 102, either by mechanical or laser methods. This allows a user to remove a sheet 12 from the roll 100 as desired, similar to the operation of a roll of paper towels. Moreover, using the roll 100 of sheets as a storage system advantageously reduces packaging materials, i.e. fitting more packages within a smaller area and can package the roll in a shrink or flow wrap rather than a packaging carton. Alternatively, the sheets 12 can be individually wrapped on the roll 100 as separate sheets in which a user simply unrolls to remove an already pre-cut sheet. In yet another approach, the sheets 12 can be stacked or folded together in a dispenser where a user can peel, pull, or otherwise remove a sheet 12 for use.

[0065] In the approach of covering a majority, or the entirety, of the first and second package portions 14, 16, the sheets 12 can be provided as a continuous roll, which would allow a consumer to cut a sheet of desired size. As such, the sheets 12 would have a functionality similar to plastic wrap, but without the tendency of plastic wrap to fold onto itself and stick.

[0066] By an alternative approach, the sheets 12 can be stored in the roll 100 in the second, folded configuration. With this approach, the sheets 12 are pre-folded and the cohesive zones 28, 30 are sealed together while detachably secured to adjacent sheets 12. As such, a user can pull and detach a sheet 12 from the roll 100. The user would then pull the first and second portions 14, 16 generally apart to open the package, insert desired contents, and reseal the package 10.

EXAMPLES

[0067] Example 1

[0068] Various blends of acrylic oligomers, tack control agents and elastomeric materials were tested for compatibility and storage stability (stability being defined as a mixture that does not form gels or visibly separate after storing for up to 3 days at room temperature). Table 1 below shows the combinations tested and the formulation levels used.

[0069] Table 1 : Cohesive Formulations Tested for Stability

% Component Provided in Final Cohesive Formulation

Cohesive

Acrylic Tack Tack Tack Component Storage Stability

Elastomer Elastomer

Oligomer Agent Agent Agent Ratio of Liquid Blend

(ACR)

Observation after

Sample No. A B C D E F - 3 days incompatible

Unstable,

4 because phases

- - 45 15 40 - 0

(Comparative) separated and

ACR too low

Stable, no visible

5

40 15 25 - - 20 0.67 gels, no phase

(Inventive)

separation

Unstable, because phases

6

40 15 - - - 45 0.67 separated;

(Comparative)

components were incompatible

Unstable,

7

60 - - - - 40 1.5 because phases

(Comparative)

separated

Unstable, gel-like

8

- - - - 60 40 0 structure formed

(Comparative)

and ACR too low

The components are identified as follows:

A = acrylated epoxidized soybean oil (CN 111 US, Sartomer Company, Exton, PA).

B = methacrylated polybutadiene (Ricacryl^® 3500, Sartomer Company).

C = tackified aliphatic acrylate oligomer (CN 3001, Sartomer Company). This component comprises a blend of an aliphatic urethane acrylate and hydrocarbon tackifier resins.

D = polybutadiene styrene copolymer (Ricon 184, Sartomer Company).

E = tackified aliphatic urethane acrylate oligomer (CN 3211, Sartomer Company). F = tackifier concentrate made with a light colored, low odor aromatic resin (PRO 11236, Sartomer Company).

Cohesive = (wt% Acrylic Oligomer)

Ratio (ACR) (wt% Elastomer + wt% Tackifier)

[0070] Stability or compatibility of these cohesive components may be a factor for manufacture, shipping, in-plant storage, and use of the liquid coating mixture. The stability was judged visually by appearance and consistency of the observed formulation after storage over a period of 3 days (about 72 hours). It was observed that Samples 1, 2 and 5 in Table 1 provided visually satisfactory blends of the various cohesive components that after 3 days remained homogeneous, i.e., the components did not visibly separate or form gels. Although Sample 2 resulted in a stable formulation, this cohesive component had an undesired ACR and did not cure well (i.e., this can be seen from the MEK Rub Cure test in Table 3 below, for similarly formulated Sample 10). However, Samples 1 and 5 provided stable cohesive blends that cured well and also had a desired ACR in the range of 0.5 to 1.5. The other sample blends either separated, became too viscous and/or gelled (i.e., Sample 8 became gel-like after 3 days). Sample 8 formed a gel, which indicated that the composition formed by the aliphatic acrylate, or component E, combined with the tackifier component F was not compatible.

[0071] Thus, to achieve a stable cohesive that is appropriate for use as disclosed herein, the stable cohesive generally needs to have one of the following and, in some cases, more than one of the following, and in other cases, all of the following factors: compatible components, curable, desired ACR, and all three component parts present (i.e., acrylic oligomer, elastomer, and a tack control agent).

[0072] Example 2

[0073] Based on the initial cohesive compatibility results for the stable formulations from Example 1, these formulations were further refined to produce five formulations of cohesive coatings that were all stable for at least 24 hours as a blend of the components indicated in Table 2. [0074] Table 2: Revised Cohesive Formulations

[0075] The components A through F are as indicated above in Example 1. Samples 9 and 10 correlate to Samples 1 and 2, respectively, from Example 1. Sample 11 is a variation of Sample 5 from Example 1. The remaining sample formulations were new.

[0076] After the five cohesive formulations exhibited good compatibility for at least one day, the five samples were all combined with about 1% of a photoinitiator (Esacure® KTO 46, Lamberti Spa, Italy) and then tested further. The photoinitiator was comprised of a liquid mixture of trimethylbenzoyldiphenyl phosphine oxide, a-hydroxyketones and benzophenone derivatives. The samples were then coated onto film substrates comprising ethylene vinyl acetate copolymer (EVA), Metallocene low linear density polyethylene (LLDPE) and about 12 percent of an organoclay composition (about 57-63% organically modified clay and maleic anhydride grafted linear low density polyethylene carrier, PolyOne Corporation, McHenry, IL). In particular, the substrate had about 77 wt% (EVA), about 10 wt% Metallocene LLDPE, and about 13 wt% organoclay composition. The samples were then cured after being coated onto the film substrates, where the curing was effected by application of UV radiation with three passes under a "D" bulb, which is a mercury with iron halide bulb. A single pass under a D bulb was approximately equivalent to 75 mJ/cm2 to 100 mJ/cm2. After the coating was cured, the cured cohesive layer was evaluated for the degree of cure and effectiveness to bond to the film. [0077] The degree of cure of the cohesive was tested using a solvent rub resistance test referred to as a methyl ethyl ketone (MEK) rub test, as per ASTM D5204. Good cure results were shown by an MEK rub value of 100 double rubs or more, which indicated that the cohesive was cured well and thus showed a resistance to the MEK rubbed over it. Poorly cured cohesives did not show much resistance to the MEK (e.g., 10 double rubs or less). MEK rub test results can be seen in Table 3 below.

[0078] Tack and initial peel of the cohesives were also observed, and reported subjectively. The tackiness of the cohesive layer was observed upon touching and the level of tack was evaluated on a scale of Low (L), Medium (M), and High (H). Similarly, the subjective force required to peel apart the samples by hand was also evaluated on a scale of L, M, and H. These test results can be seen in Table 3.

[0079] Table 3: Test Results for Cure and Preliminary Adhesion for Table 2 Formulations.

[0080] All of the samples had at least moderate tackiness and peel strength. Sample 10 had the highest subjective tack and peel but the poorest cure, as evidenced by an MEK rub test of about 10, which showed that after about 10 rubs of MEK the cohesive was removed from the substrate. Samples 12 and 13 had a haziness upon performing the MEK rub test, most likely due to component D, the polybutadiene styrene copolymer, rising to the surface when rubbed with MEK. Therefore, although Samples 12 and 13 fall within the desired cohesive ratio range, component D does not appear to be compatible with the other two components and thus is not a satisfactory cohesive compound. It was desirable to find an cohesive with a subjective tack result of medium or lower, subjective peel force of medium or higher and an MEK rub test of 100 double rubs or greater without haze formation, which at a minimum, Samples 9 and 11 exhibited.

[0081] Example 3

[0082] The curing effectiveness of three different variations of an cohesive formulation were tested by applying the cohesive to the same film substrate as described in Example 2 and then curing in three different manners; a UV-curing step ("UV Cure") performed on commercial equipment, an electron beam (EB) curing step ("EB Cure") performed on a similar commercial system as the UV-cure but utilizing electron beam technology, and an EB cure performed on laboratory equipment ("EB Lab Cure"). Table 4 below shows the formulation of the three cohesives tested. The commercial EB system and lab EB system are both compared due to the varying energy levels supplied by each. The acrylic oligomer is CN 111 US, the elastomer is Ricacryl® 3500 and the tackifier is CN 3001 as described in Example 1.

[0083] Table 4: Sample Cohesive Formulation

[0084] The "UV Cure" comprised passing the coated sample under a UV-lamp at about 25 ft/min in air and with about 2 to 4 passes, such that the sample was passed under the length of the UV-lamps 2 to 4 times. The energy provided by 1-pass of the UV lamp at 25 ft/min was equivalent to about 100 mJ/cm2. The "EB Cure" on a commercial system (Faustel Corporation, Germantown, WI) was performed under nitrogen gas at about 125 ft/min to about 250 ft/min with only one pass and at about 2 Mrad to about 2.4 Mrad, and the "EB Lab Cure" was also performed under nitrogen requiring about 6 to 8 passes under the lab EB system, which operated at about 10 ft/min. Total cumulative dose for 6-8 passes through the lab EB unit was about 2 Mrad to about 4 Mrad. It is appreciated that a smooth surface finish of the cohesive fastener is desired in some cases for a good cohesive to cohesive peel strength. If the surface of the cohesive is lumpy, such as having a consistency of an orange peel, the cohesive fasteners tend not to adhere together well. It was observed that all cured coating samples had comparably smooth and level surface finishes. After curing all of the samples, the peel strengths were tested per ASTM D3330/D3330M-04 method F, these results are shown in Table 5 below.

[0085] Table 5: Peel Strength Results for Different Cure Processes (UV vs. E-beam)

[0086] Surprisingly, it was found that an ultraviolet curing treatment (UV Cure) outperformed both of the EB cures. The EB Cure performed on the commercial line had no adhesion at all, i.e., peel strength of 0 gpli. The EB Lab Cure had some adhesion, but the UV- cured samples had the best adhesion overall.

[0087] In terms of the UV Cure results, Samples 15 and 16 had acceptable ranges of peel strengths (i.e., 480 gpli and 680 gpli, respectively) whereas Sample 14 had a lower peel strength (i.e., 200 gpli). The lower peel strength seen in Sample 14 is likely due to the cohesive formulation used with Sample 14, which did not fall within the desired range of 0.5 to 1.5 (i.e., it had a ratio of 2.2). [0088] While not wishing to be limited by theory, it is believed that a UV-radiation cure in ambient air (about 21% oxygen) provides a cure from the bottom of the sample up toward its surface due to the oxygen inhibition of free radical curing in cohesive portions adjacent or near the surface. The tacky components are more aliphatic in nature and therefore are lower in surface energy than, for example, the ester or urethane components. In some cases, chemical systems self-organize to the lowest possible energy state if allowed sufficient time. In the present case, it is believed that the slower cure rate of the UV process allows sufficient time for the tacky components of the coating to migrate toward the surface. In contrast, the EB curing process results in a much faster reaction cure rate, thus providing a more random arrangement of the polymer where it sets up cross-links within the growing polymer network too quickly for significant surface-energy driven self-ordering to develop. Thus, the EB cure may have an opposite cure pattern than the UV-radiation process, where EB curing commonly takes place in a nitrogen-purged environment and may cure faster at the surface and slower near the substrate. This can result in a completely different cohesive behavior based solely on the different cure methods. Ordinarily, such a rapid cure would be desirable, however, when curing the coating disclosed herein, such a fast cure is a disadvantage because it does not allow sufficient time to transpire in the process for the cohesive components to become fully organized.

[0089] While not wishing to be limited by theory, it is further believed that the slower cure time of the UV radiation curing allows for the growing polymer units to arrange themselves, such that polar units of the polymer favor the substrate and non-polar units favor the surface, where having the non-polar units near the surface of the substrate allows the cohesive coating to bond and stick to itself. This allows the cohesive components that are most compatible with the film substrate to congregate at the cohesive/substrate interface, thus enhancing the substrate adhesion, which may be one factor that aids in the absence of delamination from the substrate film.

[0090] Example 4

[0091] Two inventive cohesive-based reclosable fasteners, Samples 17 and 18, were prepared as indicated in Table 6. The two sample cohesives were compared to a standard pressure sensitive cohesive fastener (PSA-control, Sample 19) obtained from a commercial Nabisco Chips Ahoy Snack 'n Seal® package using a standard PSA (Fasson 5700, Avery Dennison Corp., Pasadena, CA). [0092] Table 6: Cohesive -based Fastener Formulations

[0093] The substrate that was coated comprised about 77.2% EVA, about 10%> metallocene LLDPE, and about 12.8% organoclay filler composition PolyOne 231-615 masterbatch. The masterbatch comprises about 57% to about 63% organically modified clay and a carrier that contains MA-LLDPE and polyethylene. Sample 17 was cured at a UV-curing station having an average light energy of about 730 mJ/cm2 and an average line speed of about 100 ft/min at an average oven temperature of 130°F. Sample 18 was cured at the UV-curing station having a light energy of about 700 mJ/cm2 with a line speed of about 100 ft/min at an oven temperature of 160°F. The standard cohesive, PSA-control, was already provided in a final form adhered to a cookie package (Kraft Foods).

[0094] A crumb contamination test was performed on all three packages to see if the food particles would negatively impact the sealing of its respective cohesive. The crumb test procedure comprised the following steps: first, Triscuit® crackers were obtained and crushed using a bottom of a glass jar. The breaking of the crackers in this fashion created small particles that would be consistent with what would be found in the bottom of a bag. Next, a 2 inch diameter ring fixture was placed onto the cohesive of the sample to be tested. Approximately 5 grams of crumbs were placed into the ring on the sample. The sample and ring were gently agitated back and forth to settle the crumbs onto the cohesive surface of the reclosable fastener. The ring was removed from the sample and the crumbs were gently shaken off of the sample and disposed. The ring was replaced back on the substrate in its original position and the area exposed to the crumbs was visually rated for the quantity of crumbs retained. A visual rating scale of zero to 100 was used, where zero meant no visible retained crumbs and 100 meant the total surface was covered with adhering crumbs. The results of the cracker crumb test are shown in Table 7.

[0095] Additionally, the peel strength of the cohesives was tested after contaminating with cracker crumbs. The peel strength was measured using a standard testing procedure, ASTM D3330/D3330M-04 method F, where the strength of the cohesive bond was tested by peeling one side away from the other and measuring the peel strength that was required. An initial peel strength, a subsequent peel strength after an initial contamination with cracker crumbs, and a second peel strength after a second round of contamination with cracker crumbs, where the sample was contaminated using the same procedure as the initial contamination, were measured. The results for the samples are presented in Table 7.

[0096] Table 7: Crumb Contamination Test Results

[0097] It can be seen from the results that the adhesivity (i.e., peel strength) of the PSA- control, as measured per ASTM test D3330/D3330M-04 method F, dropped to about 5% of its initial peel force value (i.e., from about 500 gpli to about 25 gpli) after only two cracker crumb exposures. In contrast, both of the cohesive -based Samples 17 and 18 retained at least about 41% of its initial peel force value after two exposures to the cracker crumbs, with Sample 18 actually showing an increase in peel force after contamination and after repeated closures and openings. Additionally, the visual crumb contamination ratings for the cohesive-based samples were 0 to 10, compared to values of 60 to 80 for the PSA-control.

[0098] A rolling ball tack test was also performed on uncontaminated Samples 17, 18, and 19, which was a modified version of ASTM D3121 and followed the test method parameters of ASTM D3121, unless otherwise specified. The modified test measured how strong the surface of the coating adhered to non-like materials, such as the polar surface of a rolling glass ball. [0099] The rolling ball method included: releasing a glass ball which was placed two inches up the standard incline specified in the ASTM method and allowing the ball to accelerate down the incline and roll across a horizontal surface of the pressure sensitive cohesive sample. The modified test version included using a glass ball instead of a metal ball, the glass ball having a diameter of about 1/8 inch, and using a shortened release point off of the incline (i.e., as indicated above, two inches up the incline). The relative tack was determined by measuring the distance the ball traveled across the cohesive before stopping, beginning from the end of the ramp. A longer rolling ball travel distance indicated lower tack to the polar surface of the glass ball, and indicated that the coating has a lower tendency to stick to rollers and metal surfaces on packaging machines, compared to coatings with a shorter rolling ball travel distance which indicated a higher tack level. A longer rolling ball travel distance may also correlate to a lower tendency to adhere to food crumbs. In this measurement, the measurement was limited to a maximum of 4 inches because the maximum sample size available for testing was 4.0 inches x 4.0 inches. Results from the rolling ball tack test are shown at Table 8.

[00100] Table 8: Rolling Ball Tack Test Results

[00101] From the results, it can be seen that the two inventive Samples 17 and 18 had lower surface tack than the control, as evidenced by the glass ball easily rolling across the surface of the reclosable fastener and off of the 4 inch long sample. On the contrary, the glass ball stuck to the PSA-control almost immediately upon contacting the PSA-control surface, which was indicative of a high tack surface of the coating.

[00102] Example 5

[00103] A peel repetition test was performed to test the reseal and peel ability over multiple repetitions. Approximately twenty samples were made; Samples 20 to 35 were made using the cohesive formulation of Sample 17 from Example 4, and Samples 36 to 38 were made using the cohesive formulation of Sample 18 from Example 4. Samples were produced on a commercial scale pilot coating line via the flexographic coating process. The liquid cohesive coating system was preheated to 160°F (71°C) and circulated through a chambered doctor blade which was mounted to an engraved chromium oxide ceramic roll. The engraved roll (which was also temperature-controlled to 160°F (71°C)) transferred the liquid cohesive coating to a patterned rubber roll. The patterned rubber roll in turn transferred the patterned coating to the moving substrate film (i.e., the process illustrated in FIG. 6). After exiting the coating station, the film traveled through a 60 ft. long oven section. A UV treater, consisting of 3 banks of UV lamps, was located at the oven exit. The line configuration with the UV zone located at the exit end of the oven resulted in the maximum path length between the coating station where the material was applied and the UV curing station, which maximized the amount of time available for the liquid cohesive coating to flow-out and level, prior to being cured into a cross-linked polymer network. It is believed that, in some cases, a smooth and level coating surface helps to achieve the desired cohesive to cohesive peel force in the fully cured cohesive.

[00104] A series of experimental coating runs were performed. Line speed, oven temperature, and the number of UV lamp banks were varied. The experimental design and experimental observations are summarized in Table 9 below. Visual surface roughness, MEK resistance, and separation of cohesive along the cohesive-to-cohesive bond line of the sample prior to testing were determined. In general, samples produced at 300 ft./min. to 500 ft./min. line speed had a rough surface appearance and low or no subjective peel force. Instrumented peel force measurement of these samples was for the most part not possible because the joined samples separated on their own accord before further tests could be carried out. Samples produced at 100 ft./min. had a smooth surface appearance and moderate cohesive to cohesive peel force. These samples were further characterized using instrumented peel force testing as summarized in Tables 10 and 11 to follow. Only the samples that did not separate on their own, as shown in Table 9, were tested in the repeated peel-reseal tests. These were Samples, 21, 22, 29, 30, 31, 32, 35, 36 and 38. [00105] Table 9: Experimental Design Used to Produce Samples for Peel Repetition Testing

Line Visual MEK Rub

Cohesive- Oven Joined

Sample Speed No. of UV cohesive Test (# of

Based Temperature samples

No. (ft/min) lamp banks surface double

Sample No. (°F) separated appearance rubs)

37 18 (Ex. 4) 500 160 3 Rough 100 Yes

38 18 (Ex. 4) 300 160 3 Rough 100 No

[00106] The first set of peel tests were performed using short intervals between peels, i.e., about three minutes between a peel-reseal cycle. Table 10 includes results for this test, where the averages of two samples tested per condition are provided. These results are compared to Sample 19, the PSA-control from Example 4.

[00107] Table 10: 3-Minute Delay Peel-Reseal Test Results

[00108] The second set of peel tests were performed using a longer duration interval between peels, i.e., about 24 hours between peel-reseal cycles, in order to understand the impact of longer cohesive-cohesive contact time, with the first peel taking place about one week after the samples were prepared. The test results for the extended delay peel-reseal samples are shown at Table 11. [00109] Table 11 : 24-Hour Delay Peel-Reseal Test Results

[00110] The results show that the samples including cohesive formulation of Sample 17 from Example 4 do not exhibit as pronounced of a decrease in peel force that typically occur with repeated peels when the duration between peels was 24 hours (i.e., Samples 21, 22, 29, 30, 31, 32, and 35 in this example). When the cohesive Sample 17 was allowed to remain in contact with itself for about 24 hours between peels, the cohesive recovered up to about 85% of its original peel force value, even after five peel-reseal cycles. Sample 30 had significantly lower average peel force values compared to the other test samples. Even though the joined samples did not separate on their own accord, it had poor surface smoothness due to the higher line speed of 300 ft/min.

[00111] Furthermore, it was surprising to find that the samples including cohesive formulations of Sample 18 from Example 4 actually increased in peel force value (i.e., Sample 36 in this example) with repeated peels at both the short and long time intervals between peel test cycles, similar to its contamination peel test results in Table 7, evidence of a full recovery of peel force after resealing. Only Sample 36 showed an increase in peel force value. Sample 36 was the sample cured using the slower line speed, which may have helped to provide a level and smooth sample surface (see Table 9). Sample 38 was made at a higher line speed than Sample 36 resulting in a rougher surface, which may be why there was a decrease in peel force value, as well as a low initial peel force value. [00112] In comparison, the PSA-control showed recovery behavior only when the interval between peels was long, i.e., 24 hours. At the shorter time interval, the control actually dropped in peel force, by about 40%.

[00113] Overall, for both peel-reseal tests, the best performers were Samples 22, 32, 35 and 36. These four samples all correlated to cohesives made with similar processing conditions. For example, all four samples had slow line speeds of 100 ft/min, with at least two or more banks of UV lamps turned on. The cohesives that failed the peel-reseal tests likely did not have sufficient time to flow out and level prior to UV curing.

[00114] Example 6

[00115] An aging study was conducted using the cohesive Samples 17 and 18 of Example 4, Table 6 in order to understand the effects of longer cohesive to cohesive contact time on peel performance. Various properties of the cohesive were tested over a seven-week period including subjective initial peel force (i.e., low, medium, high), visual appearance after peeling, subjective tack or tendency to stick to fingers (i.e., none, low, medium, high), coating durability (i.e., MEK solvent resistance test ASTM D5204), and instrumented peel (i.e., 5 consecutive peels repeated on same sample at intervals of about 3 minutes using ASTM D3330/D3330M-04 method F; two samples were tested and averaged together) all at various cohesive to cohesive contact times. The cohesives were coated onto the same film substrates that were used in Example 2. Table 12 below shows the aging results for Sample 17. Table 13 below shows the aging results for Sample 18.

[00116] Table 12: Summary of Aging Study of Sample 17

[00117] Table 13: Effect of Cohesive/Cohesive Contact Time on Repeat

Peel Performance (Sample 18)

[00118] It should be noted that the average peel strength value was an average of five repeated peels on the same sample that were consecutively peeled at intervals of approximately three minutes. Therefore, the first peel was determined and the peel strength value recorded, and the reclosable fastener sample was resealed. After three minutes had passed, the reclosable fastener was peeled apart again and the peel force strength was recorded. The process was repeated until five peels were performed. [00119] The subjective peel force, subjective tack and MEK rub test results were all good for both Samples 17 and 18 regardless of the duration of the cohesive to cohesive contact. The peel force values (i.e., initial and subsequent peels on the same sample) remained consistent for Sample 17 regardless of the duration of cohesive to cohesive contact for the range of zero days to 7 weeks. Sample 17 showed a much more consistent peel-reseal cycle than Sample 18. After the initial peel of Sample 17, the loss in cohesive to cohesive bond strength as represented by the loss in peel force upon subsequent peels was generally less than about 10% per subsequent peel, and was consistent regardless of the cohesive to cohesive contact time.

[00120] Beginning in week 3, there was a visible change in both Samples 17 and 18 (i.e., noticeable whitening and increase in opacity) upon peeling the aged samples. It is believed that this visible change is evidence of microscopic surface deformation of the cohesive due to forces acting on the cohesive surface during manual or instrumented peeling. The surface deformation did not affect the critical performance attributes of the cohesive (i.e., tack or peel strength). In the end, Sample 17 held up slightly better, with its peel strength either increasing over time, i.e., recovering peel strength, or generally maintaining about a 10% peel loss between subsequent peels.

[00121] Example 7

[00122] The inventive cohesive-based reclosable fastener Sample 17, from Example 4, was compared to three other inventive cohesive-based reclosable fasteners, Samples 39 to 41, having the formulations as indicated in Table 14.

[00123] Table 14: Cohesive-based Fastener Formulations

[00124] Component BR 144 is identified as an acrylic oligomer (BR 144, Bomar Specialties Company, Torrington, CT). Component CN 2302 is also identified as an acrylic oligomer (CN 2302, Sartomer Company). All three Samples, 39 to 41 , have incorporated the acrylic oligomer BR 144, with Samples 39 and 40 having two acrylic oligomers and Sample 41 having three acrylic oligomers present in the formulation.

[00125] The cohesives were coated onto the same film substrates that were used in Example 2. Samples 39 to 41 were cured at a UV-curing station having an average line speed of about 25 ft/min and three passes under the UV lamps totaling about 400 mJ/cm2 to about 600 mJ/cm2.

[00126] Coating durability of the four cohesives was tested (i.e., MEK solvent resistance test ASTM D5204) as well as initial peel strength using ASTM D3330/ D3330M-04 method F. A rolling ball tack test was also performed, which was a modified version of ASTM D3121 as described in Example 4, except the sample size available for testing was about 2.5 inches wide by about 7 inches long. These results are indicated in Table 15. [00127] Table 15: Test Results for Cure and Adhesion using Table 14 Formulations.

[00128] The initial peel strength, i.e., initial peel performed under laboratory conditions, increased for the new formulations by about 30%-300% compared to Sample 17, having only one acrylic oligomer component. The rolling ball tack distance increased for the new formulations by more than 300% compared to Sample 17.

[00129] From the results, it can be seen that the new formulations having two or more acrylic oligomers had an overall improved performance compared to Sample 17, as evidenced by the rolling ball test and the peel strength test. All samples had excellent cure rates, evidenced by the MEK rub test. In particular, all of the new sample formulations, i.e., Samples 39 to 41, had lower surface tack than Sample 17 and, in particular, Samples 40 and 41 had an even better low surface tack as evidenced by the glass ball easily rolling across the surface of the reclosable fastener and off of the 7 inch long sample.

[00130] Example 8

[00131] The four inventive cohesive-based reclosable fasteners of Example 7 were tested for various repeat peel tests. The samples were initially peeled apart and opened, the peel force was measured in grams per linear inch (gpli) using ASTM test method D3330/D3330M-04 method F, then resealed for three minutes, and the peel repeated. This seal-reseal was repeated every three minutes until ten data points were obtained. The results are presented below in Table 16. [00132] Table 16: Three Minute Peel Delay Test

[00133] Example 9

[00134] A 24-hour delay repeat test was performed using the same four inventive samples from Example 7. The samples were initially peeled apart and opened, the peel force required being measured. Then the samples are resealed and allowed to sit for 24 hours in a controlled environment, i.e., 72F and 50% relative humidity (RH), until they were repeeled and opened again. This is repeated until a total of five data points have been gathered, or for a period of five days. The results are presented below in Table 17.

[00135] Table 17: 24-Hour Peel Delay Test

[00136] All four of the samples maintain their peel performance throughout the five day test period, without any sample falling below 400 gpli on any of the test days. Samples 39 and 41 actually increase in peel force and recover the initial peel force or increase in peel force during the test period. Thus, allowing these samples to remain sealed for a period of at least 24 hours allows these samples to recover or increase in adhesivity.

[00137] Example 10

[00138] In Example 10, a similar test to Example 9 was performed using the four samples described in Example 7; however, after each peel opening the cohesive area was contacted with whole coffee beans, resealed, and allowed to remain closed for 24 hours, and repeeled.

[00139] After each peel opening, whole coffee beans were placed on the cohesive surface and removed in less than five minutes. The samples were resealed and allowed to sit for 24 hours in a controlled environment, i.e., 72°F and 50% RH, until they were repeeled and opened again. This is repeated until a total of five data points have been gathered, or for a period of five days. The results are presented below in Table 18. [00140] Table 18 : 24-Hour Peel Delay Test After Coffee Bean Contamination

[00141] Although the data shows a slight decrease in peel strength, the peel values still exceed 200 gpli after five peel/contamination cycles with whole coffee beans.

[00142] Example 11

[00143] A rolling ball tack test as described in Example 4 was performed on film with no cohesive for comparison to the tack values of the low tack cohesive. The results are provided below in Table 18. Roll #3 from Sample 1 took a fairly sharp turn shortly after contacting the film.

[00144] Table 18: Rolling Ball Tack Test On Uncoated Film

[00145] Those skilled in the art will recognize that a wide variety of modifications, alterations, and combinations can be made with respect to the above described embodiments without departing from the spirit and scope of the invention, and that such modifications, alterations, and combinations are to be viewed as being within the ambit of the inventive concept.

Claims

Claims Claims:

1. A sheet configured to be folded into a reclosable package, the sheet comprising:

a sheet of flexible material having edges, an interior face, and an exterior face;

a foldable portion disposed across the sheet, the foldable portion dividing the sheet into first and second panels that are configured to be folded with respect to one another about the foldable portion;

cohesive zones on the interior face of the sheet along the edges thereof, the cohesive zones having first and second cohesive opposing zone portions on the first and second panels respectively;

the first and second cohesive zone portions configured to be engaged to form a sealed package when the first and second panels of the sheet are folded together about the foldable portion; and

opposed unsealed outer edge flaps of the interior faces along each edge of the sealed package between the edges of the sheet and the cohesive zones, the opposed unsealed outer edge flaps configured to be gripped and pulled apart to separate the first and second cohesive zone portions.

2. The sheet of claim 1 wherein the sheet includes opposing end edges and opposing side edges, and further comprising complementary coupling components disposed on the interior face of the sheet along the end edges thereof, one of the complementary coupling components along one of the opposing end edges and the other of the complementary coupling components along the other opposing end edge; wherein the cohesive zones extend between the complementary coupling components and the foldable portion along each of the opposing side edges.

3. The sheet of claim 2 wherein the opposed unsealed outer edge flaps of the interior faces of the folded sheet are further disposed between each end edge of the sheet and the respective complementary coupling component.

4. The sheet of claim 2 wherein the complementary coupling components are interlocking strips.

5. The sheet of claim 4 wherein the interlocking strips fasten together with the use of a zipper member.

6. The sheet of claim 1 further comprising one or more intermediate cohesive zones extending between the cohesive zones on the interior face of the sheet along the edges thereof.

7. The sheet of claim 1 wherein the foldable portion is a fold line.

8. The sheet of claim 7 wherein the fold line is marked with indicia disposed either on the exterior face or the interior face.

9. The sheet of claim 7 wherein the fold line is pre-crimped.

10. The sheet of claim 1 wherein the opposed unsealed outer edge flaps comprise first and second flaps and at least a portion of the first flap is larger than a portion of the second flap.

11. A sheet configured to be folded into a reclosable package, the sheet comprising:

a sheet of flexible material having edges, an interior face, and an exterior face;

a foldable portion disposed across the sheet between the edges, the foldable portion dividing the sheet into first and second flexible panels that are configured to be folded with respect to one another about the foldable portion;

a cohesive material disposed on the sheet interior face along edges of the first and second flexible panels;

the cohesive material configured to align and be engaged together in response to the first and second panels of the sheet being folded together about the foldable portion;

the cohesive material including a UV-cured pressure sensitive material including at least one UV-curable acrylic oligomer, at least one tack control component, and optionally at least one elastomeric material;

an cohesive component ratio (ACR) of the UV-cured pressure sensitive cohesive defined by formula (A) where the weight percent of the UV-curable acrylic oligomer relative to the sum of the weight percents of the tack control component and the optional at least one elastomeric material is about 0.5 to about 1.5 (wt% UV-curable acrylic oligomer) (A);

(wt% tack control component + wt% elastomeric material) the ACR effective so that the reclosable UV-cured cohesive-based fastener has a first peel adhesion between the engaged cohesive of about 100 grams per linear inch (gpli) to about 900 gpli and up to five subsequent peel adhesions between the engaged cohesive each about 30 percent to about 200 percent of the first peel adhesion; and

wherein the ACR and the package walls are effective to form a bond strength of the UV- cured pressure sensitive cohesive to the sheet interior face greater than the first peel adhesion and the subsequent peel adhesions between the cohesive so that the first and second panels can be repeatedly peeled open without delaminating the opposing cohesive layers from the sheet interior face.

12. The sheet of claim 11 wherein the sheet is detachably secured to a plurality of sheets in a rolled configuration.

13. The sheet of claim 12 wherein the plurality of sheets are rolled in a folded configuration.

14. The sheet of claim 11 further comprising one or more intermediate cohesive zones extending between the cohesive disposed on the interior face of the sheet along the edges thereof.

15. The sheet of claim 11 wherein the foldable portion is a fold line.

16. The sheet of claim 15 wherein the fold line is pre-crimped.

17. The sheet of claim 11 wherein:

the sheet has side edges and end edges;

the foldable portion is disposed across the sheet between the side edges; and the cohesive material disposed on the sheet interior face includes side strips of cohesive material disposed along the side edges and end strips of cohesive material disposed along the end edges of the first and second flexible panels.

18. The sheet of claim 17 wherein the strips of cohesive material disposed along the edges of the first and second flexible panels are spaced therefrom to provide cohesive-free gripping areas.

19. The sheet of claim 17 wherein a first peel force between the engaged end strips of cohesive material is less than a first peel force between the engaged side strips of cohesive material.

20. The sheet of claim 19 wherein the first peel force of the end strips of cohesive material is between about 100 gpli and 200 gpli; and the first peel force of the side strips of cohesive material is between about 300 gpli and about 900 gpli.

21. The sheet of claim 17 wherein a corner region of the end and side strips of cohesive material is scalloped.

22. The sheet of claim 17 wherein outer portions of at least one of the end and side strips of cohesive material is scalloped to provide easier opening when the strips of cohesive material are engaged.

23. The sheet of claim 11 wherein the cohesive material is disposed across a majority of the interior face of the sheet.

24. The sheet of claim 23 wherein the cohesive material is disposed across the entire interior face of the sheet.

25. A sheet configured to be folded into a reclosable package, the sheet comprising:

a sheet of flexible material having end edges, side edges, an interior face, and an exterior face; a foldable portion disposed across the sheet, the foldable portion dividing the sheet into first and second flexible panels that are configured to be folded with respect to one another about the foldable portion;

complementary coupling components disposed on the interior face of the sheet along end edges thereof, one component along one of the opposing end edges and the complementary component along the other end edge;

opposing cohesive strips disposed on the interior face of the sheet along each of the side edges thereof;

a foldable portion disposed across the sheet between the side edges, the foldable portion dividing the sheet into first and second fiexible panels that are configured to be folded with respect to one another about the foldable portion to align and sealingly engage the complementary coupling components and the cohesive strips to form a sealed interior; and

opposed unsealed outer edge flaps of the interior faces of the folded sheet disposed along each side and the end of the sealed package between the side edges and the cohesive strips and the end edges and the coupling components, the opposed unsealed outer edge flaps configured to be gripped and pulled apart to separate the first and second cohesive strip portions to separate engaged cohesive strips along the side edges and engaged coupling components along the end edges.

26. The sheet of claim 25 wherein the foldable portion is a fold line.

27. The sheet of claim 26 wherein the fold line is pre-crimped.

28. The sheet of claim 25 wherein the coupling components are interlocking strips.

29. The sheet of claim 28 wherein the interlocking strips fasten together with the use of a zipper member.

30. The sheet of claim 25 further comprising one or more intermediate cohesive strips extending between at least one of the side cohesive strips and the coupling components; wherein the one or more intermediate cohesive strips are configured to align with folding of the sheet to provide the ability to divide the sealed interior into a plurality of sealed interiors.