Packages and methods of manufacture are described herein and, in particular, methods of forming flexible film packages using a cold-sealed pressure sensitive adhesive to form at least a portion of the package.
Flexible, semi-rigid and rigid packages are known in the art for use in containing discrete consumer products. For example, such packages may be used to contain comestible consumer products such as crackers, chocolate, cookies, cheese, sandwiches, biscuits, candy, meat products, nuts, dried fruits and vegetables, and the like, and other consumable products such as chewing gum.
Flexible film packages have numerous advantages. For example, they can be manufactured at substantially lower cost than rigid containers, are lightweight (resulting in lower transportation costs), and can reduce space required for storage. Flexible packaging can include flow-wrap type packages, which may employ a continuous film or web to envelop a product during assembly or formation of the package. Flow-wrap packages can be, for example: horizontal or vertical fin seal or lap seal, end seal wrap, horizontal bagged and pillow-pouch packaging. In a typical flow-wrap package configuration a flexible film (such as polyethylene (PP), oriented polypropylene (OPP), metalized oriented polypropylene (MET OPP), polyethylene terephthalate (PET) or polypropylene) is positioned adjacent to a product, then wrapped around the product. Next, the product is sealed within the flexible film by a package contents cavity. This cavity can be formed by seals to the flexible film defining package ends or film edges. These seals may be permanent and also may even provide some structural integrity to the package. The film seals are typically formed by heat activation of the film. A disadvantage of using heat activation is that some products in such packages may be deformed and/or damaged by the heat.
Some attempts to use a cold-seal pressure sensitive adhesive (PSA) to seal some types of packages are known. U.S. Pat. No. 3,630,346 to Burnside discloses a flexible closure film layer to cover an opening of a blister pack. The film layer has a protective backing portion of its liner stripped away to expose peripheral PSA for sealing the blister opening. Portions of cut outs of the liner remain so that PSA is not exposed to the package interior.
US Pub. 2010/0172604 to Anderson describes the use of PSA applied to a flexible film to form a reclosable thermoformed container. Specifically, a PSA layer is used to reseal a flexible cover portion onto a rigid thermoformed container bottom.
In the art, reclose features may optionally be included on flexible film packages to provide users with an easy and efficient manner of preserving product for later consumption. The reclose feature may provide product containment or even a barrier to moisture and gas. A disadvantage of packages such as described in Burnside and Anderson is that flexible film packaging embodiments are not possible and could not be formed in processes such as vertical flow wrap assembly.
An exemplary embodiment of a cold seal package forming device is provided, which may have a scoring device configured to score a continuous film laminate, the film laminate comprising a pressure sensitive adhesive (PSA) layer disposed between a first film layer and a second film layer; a stripping device configured to strip at least a portion of the second film layer to expose the PSA; a forming device configured to form the film laminate into a package having an interior; a feeding device configured to feed a product into the package interior; a sealing device configured to seal the product within the package interior via adherence of the exposed PSA on a portion of a package periphery; and a separating device configured to singulate the package from a continuous web of the film laminate.
In one exemplary embodiment, the stripping device is configured to strip the second film layer to expose the PSA corresponding to the portion of a package periphery to form longitudinal seals and end seals. Optionally, the stripping device can be configured to strip the second film layer to expose the PSA to form one or more gussets.
In one exemplary embodiment, the sealing device may further comprise one or more package end sealers, wherein the package end sealers are heated end sealers.
An exemplary method is provided for producing a flexible package from a continuous film laminate having a pressure sensitive adhesive (PSA) layer disposed between a first film layer and a second film layer. The method may comprise scoring the second film layer of the film laminate corresponding to at least a portion of the periphery of the package to be formed; stripping predetermined portions of the scored second film layer to expose the PSA; forming a package interior by sealing the exposed PSA to the at least a portion of the periphery of the package; feeding a product into the package interior; sealing the product within the package interior; and separating individual packages from the continuous film laminate.
In one exemplary method the step of scoring the second layer of the film laminate can optionally comprises scoring the second layer of the film laminate offline of the package production.
In one exemplary method the step of forming the package interior may optionally include wrapping the film laminate around a vertical form filling tube, and the step of stripping the predetermined portions of the second film layer from the film laminate can occur prior to the wrapping of the film laminate around the vertical form filling tube.
In one exemplary method the step of scoring the second layer of the film laminate comprises scoring a portion of the edges of the continuous film laminate, and wherein the step of stripping the predetermined portions of the second film layer exposes the PSA to allow formation of a longitudinal seal.
In one exemplary method the step of scoring the second layer of the film laminate may optionally provide a PSA layer disposed between the first film layer and the second film layer with scores to allow exposure of the PSA to form gussets.
In one exemplary method the step of sealing the product within the package interior further comprises joining the exposed PSA to the film laminate.
In one exemplary method the step of the step of scoring the second layer of the film laminate may optionally have the step of scoring the second layer of the film laminate corresponding to an entire periphery of the package.
In one exemplary embodiment, a flexible package for containment of discrete products, the package may have a flexible film laminate having a first film layer, a second film layer, and a pressure sensitive adhesive (PSA) layer disposed between the first film layer and the second film layer; wherein the second film layer covers a portion of the first film layer and a portion of the PSA is exposed; a package interior formed by portions of the flexible film laminate adhesively laminated to one another by the exposed PSA; and an outer flap portion formed by an outer score line through the first film layer; an inner flap portion formed by an inner score line through the second film layer; wherein the inner score line is displaced from the outer score line so as to form therebetween a marginal region of the outer flap portion that extends beyond an edge of the inner flap portion; wherein the inner score line is configured to provide an opening into the package interior when the inner and outer flap portions are peeled back; wherein the outer score line is configured to penetrate through an outer surface of the laminate but not through an inner surface of the laminate; and wherein the inner score line is configured to penetrate through an inner surface of the laminate but not an outer surface of the laminate.
Packages and methods of manufacture are described herein and, in particular, methods of forming flexible film packages using a cold-sealed pressure sensitive adhesive to form at least a portion of the package. The present embodiments allow for flexible film package forming in a variety of ways not presently known in the art.
For example, according to one approach, a single laminated film layer may be used to form a flexible flow wrap package by either vertical or horizontal methods. The laminate may include a film layer/matrix layer, a pressure sensitive adhesive (PSA) layer and a liner layer to cover the PSA layer. In this instance, portions of the liner layer may be stripped to expose film portions to allow seals to be formed adjacent to other portions of the film layer configured to form a package interior configured to retain package contents (e.g., comestible or other consumable products). Thus, as will be shown herein in the exemplary embodiments, vertical or horizontal package formation is possible subsequent to stripping the liner layer.
In some embodiments, additional liner may also be removed from the laminated film layer to form optional package features, such as pleats, pouches, reclose flaps, and the like and combinations thereof. For example, a reclose feature can include a preconfigured “bottom cut” to the liner layer of film laminate (i.e., just through an interior side of the laminate film layer directed to the package interior) to define a package opening and a “top cut” (i.e., just through an exterior side of the laminate film layer directed to the package exterior) to score an opening flap. Another optional package feature may be provided by cutting additional liner layer to expose a portion of the PSA adjacent to the product within the package interior to hold it in place. Yet another optional package feature may be provided by cutting additional film layer to expose a portion of the PSA on the package exterior to allow adjacent packages to be held (stacked) together.
In another exemplary approach, a package may be generally formed by two film layers laminated together by the exposed PSA oriented along or adjacent to (i.e., within 3 cm of the film edge, and preferably between 1 mm to 1 cm) the edges of one or both of the film layers. In this instance, at least one of the two film layers may be a laminated film having, as described above, at least the film layer, the PSA layer, and the liner layer. In this approach, a portion of the liner layer may be stripped away following a predetermined bottom cut to expose the laminate film's PSA to seal/join to the second film layer. Optionally, the package may be formed to provide a pull tab extending past the portion of the exposed PSA to allow a user to pull the two film layers apart to expose the package interior. This feature could also be included in the single film laminate approach described above.
It is noted that although the exemplary embodiments are described herein as using a film laminate, film layers without a liner may also be used. In some embodiments, the PSA may be pattern applied along (or adjacent to) the peripheral edges of one of the film layers plus wherever else the PSA is desired. In another embodiment, the PSA may be extruded onto the package. In still other embodiments, the laminate may have a PSA layer across the entire film surface, but then have deadened zones formed by over printing, UV light, and the like.
It is also noted that as described herein, a PSA seal is a “cold” seal formed under ambient temperatures such that heat activation is not required to form a seal. For example, ambient temperature may be in the range between about 20° C. and about 26° C. (about 68° F. and about 79° F.). Thus, heat is not applied to the film during package formation and the film is otherwise not heat activated to form a seal. This does not mean though that heat activation is precluded to form some portions of the package of the present embodiment. Heat-activated film may be used with an applied PSA so that that package may optionally use heat activation to form a portion of the package. Thus, the present embodiments allow for package formation without using a heat seal, though a heat seal may optionally be used to form a portion of the package.
The cold seal-formed packages according to the present embodiments described herein provide several advantages. For example, use of a cold seal allows for packaging products subject to low melting points, such as chocolate, ice cream, other confections, and the like. With the elimination of a heat sealing step, production speed can be increased. The time needed to heat the film and form the seal is eliminated for that portion of the package formation. Further, as mentioned above, using PSA laminated films, a PSA reclosure flap may be formed either on-line (i.e., contemporary with package formation) or off-line (i.e., prior to package formation). Also, where a PSA is used to form a package seal, the thickness of the film, the composition of the film, and optional laminate layers are not as critical compared to the use of heat-activated film. For example, the film can be thicker with a cold seal package formation since heat penetration through the thickness of the film is not a facture. Thus, time, pressure and heat variables as a function of film thickness are removed and/or coposition. Additionally, employing a cold-seal PSA reduces energy needed to seal a package of the present embodiments since the energy needed to heat the film is not present.
The present embodiments allow for a variety of manufacturing options such as dual film, dual/multiple lane, vertical and horizontal package formation, blister pack, flow-wrap, therma-formed packages, and the like and combinations thereof. Trays to contain product can also be included during package formation. As described above, a bottom die cut on the liner layer of a film laminate may be used in the formation of a cold seal formed package. In some embodiments, the liner layer can be cut off-line. The liner may also be removed off-line. In some embodiments, due to the narrowed diameter of the film roll where the liner layer has been removed and the PSA is exposed, a release layer may be used to allow the PSA to separate from the film layer as it is unrolled during package formation. In others methods, the liner layer may be stripped off just prior to enveloping the product since the thickness of the film laminate will be thinner where the liner layer is removed. A recessed die cut can be difficult to execute in a vertical bagging application given the unevenness of the roll, but leaving a portion of the liner layer in place after stripping the portion of the liner layer to expose PSA provides an advantage. By leaving the liner layer in place for the non-PSA surfaces, the film laminate can slide, e.g., over forming tubes, during package formation. This is possible because the PSA is recessed from the surface of the forming tube by the thickness of the liner. The liner layer can be, for example, from about 40 gauge (about 0.40 mils, about 0.0101 mm) to about 200 gauge (about 2 mils, about 0.0508 mm).
Thus, the current embodiments allow cold seal package formation on vertical (and even horizontal) form/fill applications. In one approach, the liner layer is removed and the PSA is exposed just before reaching the forming tube where it can be applied to the film to form a seal on at least a portion of the package. This type of seal can be used to form, in a variety of combinations, an end seal or seals, a fin seal, pleats, pouches, opening flaps, and the like. Stripping the liner layer close to the addition of product minimizes the need for modifications to equipment to address the offset of the film landscape (e.g., unevenness) caused by removal of a portion of the liner layer. With the film roll even (i.e., no liner removed), the film can have a longer shelf life. For example, metal lined layer the metal barrier may be stripped away, therefore not having a barrier layer everywhere. Alternately, with a recessed PSA where the liner layer has been removed off-line, a release layer is not needed on the top surface of a roll of film, therefore a stronger adhesive can be used.
In vertical form filling package devices 100 of
Other advantages of removing a portion of the liner layer 38 until it reaches the forming tube 109 is that the PSA 36 has a longer shelf life when it is not exposed to ambient air for long periods of time. Also, on preformed rolls, the roll can be unbalanced after the liner portions have been removed since the film has two thicknesses. Thus, in this approach it is preferred that the liner layer 37 is stripped as late in the forming process as possible, for example, just before the forming tube 109 is reached. The package forming device 100 may include an optional gussetting device 140 that may utilize a cold seal or hot seal, depending on whether the liner layer 37 has been stripped. The gusseting device 140 can be positioned upstream of the forming tube 109 (
example: horizontal or vertical fin seal or lap seal, end seal wrap, horizontal bagged and pillow-pouch packaging. In a typical flow-wrap package configuration a flexible film (such as polyethylene (PP), oriented polypropylene (OPP), metalized oriented polypropylene (MET OPP), polyethylene terephthalate (PET) or polypropylene) is positioned adjacent to a product, then wrapped around the product. Next, the product is sealed within the flexible film by a package contents cavity.
Exemplary packages 30, as illustrated herein, can be formed by a continuous flexible film web 37 having a width and a longitudinal axis along the length of the package formed therefrom. Flexible film web 37, as suggested above, may be a laminate with several layers of material. Such layers may include, for example, a PET layer, an OPP layer, a polyethylene (PE) layer, a MET OPP layer, a polypropylene (PP) layer, and/or a polylactic (PLA) layer, to note a few options. These layers may be joined by one or more adhesives or by an extrusion process. Alternatively, the flexible film web 37 may be a single layer polymer or a mono-web. Since the flexible film web 37 is at least partially hermetically sealed, the flexible film web 37 preferably provides a gas and moisture barrier. By one approach, the flexible film web 37 may be about 1 mil to about 5 mil (about 100 to about 500 gauge; about 0.0254 to about 0.127 mm) in thickness. By another approach, such as that employed with an optional extrusion lamination, the flexible film web may be about 0.47 mil to about 0.98 mil (about 47 to about 98 gauge; about 0.012 mm to about 0.025 mm) in thickness. In one illustrative embodiment employed with extrusion lamination, the flexible film web 37 may be about 0.67 mil to about 0.71 mil (about 67 to about 71 gauge; about 0.017 mm to about 0.018 mm) in thickness. For the above extrusion lamination examples, the extrudate also will add about 0.4 mil to about 1.2 mil (about 40 to about 120 gauge; about 0.01 to about 0.03 mm) of additional thickness to the flexible film 37. The thickness of the flexible film web 37 may be a function of the desired barrier to gas, moisture, and light, along with the level of desired structural integrity, the desired depth of score line, and the available manufacturing equipment. As noted above, the packages according to the present embodiments may be formed of a film that is thicker than previously employed in packages formed using heat seals.
Optional lamination layers can include heat activation laminates, metalized layers, coatings, glazes, printing and the like. In optional embodiments where a heat seal may be employed to form at least a portion of the package 30, the flexible film web 37 may include a lamination on the surface of the film directed to the interior of the package 30 that includes a heat sealable copolymer. In some configurations, the heat sealable polymer forms a seal at temperatures between, for example, about 50 and about 300° C. In some embodiments, flexible film 37 also may be a pressure sealing film. For example, the pressure sealing film may form a seal between, for example, a pressure of about 0.7 to about 7.0 kg/cm. By one approach, the pressure sealing film may form a seal at about 5.6 kg/cm.
A sealant layer may be also be included in the film lamination when a heat seal is employed. The sealant layer may be formed from a variety of polymer sealants, such as a heat activated polymer sealant layer like ethylene vinyl acetate (EVA), ionomer plastic (such as that sold under the trade name SURLYN by DuPont), metallocene, and organoclay, among others. In one example, seals, such as fin seals, can be formed using a heat activated sealant layer. In addition, cold sealant and pressure sealants also may be used with the configurations disclosed herein. It will be appreciated that food grade sealants would be employed when the products within the flexible overwrap film are food products.
In addition to the various laminate layers mentioned above, additional laminate layers such as, stiffeners, ink, release layers, also may be incorporated into the laminate structure of the flexible film 37. In one configuration, stiffeners may be added to flexible film 37 to increase the stiffness of the flexible film 37. These stiffeners may be in addition to the stiffness adjustments that may be made by changing the thicknesses or densities of the previously mentioned laminate layers. These stiffeners may be added as a component of the extruded film or as a separate layer. For example, a laminate layer such as a polyamide polymer (e.g., nylon) may be included in the laminate film structure of flexible film. By one approach, nylon may be added as a laminate layer that is held to the remainder of the film structure by an adhesive. Further, in one configuration, the nylon layer may be positioned between other layers such that the other flexible film layers are attached on each side of the nylon layer (i.e., a tie layer). In one configuration, a film structure having a thickness of about 2 mil, may include a nylon layer of about 6-10 percent of the film thickness or about 0.003 mm to about 0.005 mm. By yet another approach, the nylon layer may be about 0.004 mm. In one approach, the nylon layer comprises about 8 percent of the total thickness of the flexible film 37.
As noted, an ink layer may be formed in the laminate as an additional laminate layer. For example, one specific laminate may include ink and a primer disposed between other film layers such as a PET layer and an OPP layer. Alternatively, the ink may be a surface printed layer with a release over-lacquer such as that used for a mono-web. Other additional layers may include a metalized layer, as noted above.
Preferably, flexible film 37 has a PSA lamination 36. A PSA as described herein is an adhesive typically based on an elastomer with a suitable ‘tackifier’. The resultant adhesive forms a bond when pressure is applied to join the adhered surfaces. No other activation steps are required to form the adhesive bond, but it will be appreciated that adhesive bonds formed using activation steps may also be used. As shown, for example in
PSA 36 preferably maintains adhesiveness after initial separation. PSA 36 is preferably neutral or non-reactive to the product to be packaged in the package 30. By one approach, PSA 36 may include, for example, a cold formed adhesive, a hot melt adhesive, a cold seal adhesive, a natural or synthetic latex adhesive, a low tack adhesive, ethylene vinyl acetate (EVA), an acrylic adhesive (such as a water-based or solvent acrylic adhesive), a styrene block copolymer adhesive, a butyl rubber adhesive, a silicone rubber adhesive, a natural rubber adhesive, a nitriles adhesive, an acrylic emulsion adhesive, and combinations thereof. Further, the PSA 36 may be extruded, coextruded, printed, or combinations thereof onto film layer 37. In one configuration, the PSA 36 can be an acrylic water-based adhesive. PSA 36 may be a variety of thicknesses. By one approach, the PSA 36 may be about 0.5 to about 1.5 mil (about 50 to about 150 gauge; about 0.0127 to about 0.0381 mm) in thickness. The PSA 36 may be suitable for reclosing in a variety of conditions, such as ambient and refrigerated conditions, to note but a few.
In some configurations, the PSA 36 may provide a substantially hermetic seal even under refrigerated conditions (i.e., the pressure sensitive adhesive can be operable in a temperature range of about −10° C. to about 90° C.; and preferably in the range of about 2° C. to about 7° C.). The PSA 36 may be applied directly to the flexible film 37, but also may be applied to ink or another coating on the flexible film 37. By one approach, the PSA 36 remains attached to the flexible film 36, even after repeated separation, such as when an optional package opening is employed. In some embodiments, the PSA exhibits a greater bond strength to desired surfaces (such as not delaminating from the flexible film) than to the liner 38. Again, if the products within the flexible overwrap film are food products, then a food grade PSA would be employed.
Exemplary packages formed by the present embodiment devices and methods are illustrated in
Scoring device 78, as described herein and shown, for example, in
Film scores 40 and 48 can be developed for a variety of configurations and function and the present embodiments show but of a few of the possible embodiments. For example, in addition to scoring the liner layer 38 to allow removal of the liner layer 38 to form package seals and/or pleats, film score 40 may also form a flap upon opening of the package 30. Other configurations for film scores are possible within the scope of the present embodiments and may depend on the products being packaged, whether a structural support is being incorporated into the flexible film package 30, and the manufacturing equipment available, among other factors. In one approach, film score 40 and 48 may define a package opening 31 that permits access to at least 70 percent of the products within the flexible overwrap upon initial opening of the package 30. By yet another approach, film score 40 and 48 defines a package opening 31 that permits access to up to 90 percent of the product within the package. In another configuration, film score 40 and 48 may define a package opening 31 permitting access to at least 50 percent of the product within the package 30.
Package 30b may be formed by device 106 of
As shown in
Additional package configurations according to other approaches are shown in
Variations of package 30, as shown and described herein, have been shown in the form of a generally rectangular shape. However, it is within the contemplation of the present embodiments that the package could be formed in a variety of shapes, and the embodiments are not restricted to the shapes which are shown. For example,
In other embodiments, package assembly devices of
Accordingly,
Again, it is noted that other configurations are possible to vary when and where the gussets are formed, if any, when the film is scored (off-line and on-line) and which of the end seals, fin seal, and gussets are cold seals.
While preferred embodiments have been described in detail, variations and modifications can be effected within the scope of the present embodiments. Throughout this specification and the drawings and figures associated with this specification, numerical labels of previously shown or discussed features may be reused in another drawing figure to indicate similar features.
Filing Document | Filing Date | Country | Kind |
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PCT/US2016/067483 | 12/19/2016 | WO | 00 |
Number | Date | Country | |
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62273277 | Dec 2015 | US |