Packaging films

Abstract

A packaging film and method for sealing packaging films with the packaging film being made from recyclable materials and having a high barrier to water vapor and gasses such as oxygen. The packaging film being made of a plastic and the packaging film being recyclable and suitable for high speed commercial packaging.

Description

TITLEPACKAGING FILMSCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and the benefit of U.S. Provisional Patent Application No. 63 / 623,998, titled “PACKAGING FILMS,” filed on January 23, 2024, the disclosure of which is incorporated herein by references in its entirety.TECHNICAL FIELD

[0002] The present disclosure relates to films suitable as packaging films, packages employing such films, and methods for making the same. In particular, the present disclosure relates to packaging films comprising a polymer film layer having a single polymer film, a heat seal layer, and a heat-resistant layer. In embodiments, the packaging film is recyclable.BACKGROUND

[0003] Packaging films are used to package and protect food products. Packaging films provide a barrier between the environment and the interior of a sealed package. Food products are often packaged using techniques such as “flow wrapping”. Flow wrapping involves forming a cover or an entire package container to cover and encapsulate a product, e.g., a food product. Flow wrapping typically involves (i) wrapping or covering a product with a packaging film, and (ii) heat sealing the packaging film around the product in preparation for selling the film- protected product, where steps (i) and (ii) are conducted at relatively high speeds suitable to quickly produce large quantities of packaged material.

[0004] The package is formed by sealing portions of the film to either a container (in the case where the film is provided as a cover layer) or to itself where the packaging film itself forms the package. Sealing is typically accomplished via heat sealing. For production to be run at scale, there are short time frames to accomplish sealing of the packaging film. Typical packaging films are multi-layer constructions where the film is constructed such that the sealing properties are built into the film to accomplish sealing. In particular, many films employ polymers with high melting points that can withstand higher temperatures to quickly effect sealing the package.

[0005] As sustainability initiatives become more prevalent, there is a trend to provide packaging films that are recyclable. Polyolefin films, e.g., polyethylene, are of particular interest as they are particularly suitable to being recycled. Polyolefins such as polyethylene, however, have lower melting points than many films, such as polyester films, commonly used in packaging films. As such, the use of polyolefins in packaging films is a challenge, particularly for heat sealing applications, because it is difficult to provide films that can transfer heat through the film to the heat sealing layer without damaging the film. Pre-heating polyolefin films is also a challenge because such films can become tacky' making them difficult to unwind during processing.SUMMARY OF THE INSTANT DISCLOSURE

[0006] The following summary' of this disclosure provides a basic understanding of aspects of the instant packaging film and packaging method. This summary' is intended to neither identify key or critical elements nor define any claim limitations or limitations to embodiments. Furthermore, this summary' may provide a simplified overview of some aspects that may be described in greater detail in other portions of this disclosure.

[0007] Provided is a packaging film and method that is suitable for forming a package from such packaging film. In accordance with one aspect, there is provided a packaging film comprising a single polymer film, a heat seal layer disposed about a first surface of the singlepolymer film, and a heat-resistant coating layer disposed about a second surface of the polymer film layer.

[0008] In embodiments, the single polymer film is a recyclable polymer film. In embodiments, the single polymer film is a polyolefin film such as, for example, polyethylene. The packaging film with a single polymer film layer in conjunction with the heat-resistant coating has been found to provide a construction that is suitable for forming a package using heat sealing techniques without damaging the packaging film. The construction allows for providing a package with a recyclable polymer such as, for example, polyethylene.

[0009] A packaging material comprising a single polymer film has been found to allow for quick transfer of heat to allow for sealing at a relatively high rate or line speed in forming a sealed package or sealing the packaging material to an article. The packaging material comprising a single polymer film can provide improved processing compared to conventional laminated packaging material structures. Additionally, the employing a single polymer film provides for a smaller overall quantity of polymeric material, which may be of interest for sustainability initiatives.

[0010] In one aspect, provided is a A packaging film, comprising: (a) a single polymer film having a first surface and an opposing second surface; (b) a seal layer disposed on the first surface of the single layer polymer film layer; and (c) a heat-resistant layer disposed about the second surface of the single layer polymer film layer

[0011] In one embodiment, the single polymer film comprises a polyolefin.

[0012] In one embodiment, the polyolefin is selected from polyethylene.

[0013] In one embodiment, the polyolefin is selected from high density polyethylene.

[0014] In one embodiment in accordance with any of the previous aspects or embodiments, the single polymer film is biaxially oriented.

[0015] In one embodiment in accordance with any of the previous aspects or embodiments, the single polymer film is machine direction oriented.

[0016] In one embodiment in accordance with any of the previous aspects or embodiments, the packaging film comprises a barrier layer. In one embodiment, the barrier layer is disposed between the single polymer film and the heat-resistant layer.

[0017] In one embodiment, the barrier layer comprises a metal, an oxide, a nanoclay, or a polymeric material.

[0018] In one embodiment in accordance with any of the previous aspects or embodiments, the heat-resistant coating is selected from a lacquer.

[0019] In one embodiment in accordance with any of the previous aspects or embodiments, the heat-resistant coating is selected from a radiation curable polymer.

[0020] In one embodiment in accordance with any of the previous aspects or embodiments, the single layer polymer film layer has a thickness of from about 18pm to about 56pm.

[0021] In one embodiment in accordance with any of the previous aspects or embodiments, the seal layer has a seal initiation temperature of about 110 °C or lower.

[0022] In one embodiment in accordance with any of the previous aspects or embodiments, the seal layer has a seal initiation temperature of from about 60 °C to about 110 °C.

[0023] In one embodiment in accordance with any of the previous aspects or embodiments, the packaging film is recyclable.

[0024] In another aspect, provided is a package comprising the packaging film in accordance with any of the previous aspects or embodiments,.

[0025] In one embodiment, the package is formed from packaging film.

[0026] In one embodiment, the package comprises a container and a cover, the container having a bottom member, one or more side walls extending from the bottom member and defining a package interior and an opening adjacent an upper end of the one or more side walls, and wherein the cover is disposed along the upper end of the one or more side walls, and the cover is formed from the packaging film.

[0027] In one embodiment in accordance with any of the previous aspects or embodiments, the package comprises a food product disposed within the package.

[0028] The following description and the drawings disclose various illustrative aspects. Some improvements and novel aspects may be expressly identified, while others may be apparent from the description and drawings.BRIEF DESCRIPTION OF THE DRAWINGS

[0001] The accompanying drawings illustrate embodiments of the disclosure in accordance with various aspects, in which:

[0029] FIG. 1 is a top view of a packaging film in accordance with an embodiment of the present technology;

[0030] FIG. 2 is a cross-sectional view of the package from line A- A in FIG. 1,;

[0031] FIG. 3 is a cross-sectional view of a packaging film in accordance with an embodiment of the present technology;

[0032] FIG. 4 is a cross-sectional view' of a packaging film in accordance with an embodiment of the present technology;

[0033] FIG. 5 is a cross-sectional view' of a packaging film in accordance with an embodiment of the present technology;

[0034] FIG. 6 is a cross-sectional view of a package formed from a packaging film in accordance with the present technology;

[0035] FIG. 7 is a graph showing the sealing range of various films; and

[0036] FIG. 8 is a graph showing the sealing range of various films.

[0037] The invention may be embodied in several forms without departing from its spirit or essential characteristics. The scope of the invention is defined in the appended claims, rather than in the specific description preceding them. All embodiments that fall within the meaning and range of equivalency of the claims are therefore intended to be embraced by the claims.DETAILED DESCRIPTION

[0038] Reference will now be made in detail to exemplary embodiments of the present invention. It is to be understood that other embodiments may be utilized, and structural and functional changes may be made without departing from the respective scope of the invention. Moreover, features of the various embodiments may be combined or altered without departing from the scope of the invention. As such, the following description is presented by way of illustration only and should not limit in any way the various alternatives and modifications that may be made to the illustrated embodiments and still be within the spirit and scope of the invention.

[0039] As used herein, the words "example" and “exemplary” mean an instance, or illustration. The words “example” or “exemplary” do not indicate a key or preferred aspect or embodiment. The word “or” is intended to be inclusive rather an exclusive, unless context suggests otherwise. As an example, the phrase “A employs B or C,” includes any inclusive permutation (e.g, A employs B; A employs C; or A employs both B and C). As another matter, the articles “a” and “an” are generally intended to mean “one or more” unless context suggests otherwise.

[0040] As used herein, the word “comprise” and variations such as “comprising” or “comprises” will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

[0041] As used herein, the words “substantially,” “predominantly,” “about,” and variations thereof are intended to note that the described features are equal or approximately equal to a value or characteristic, as desired, reflecting tolerances, conversion factors, rounding off, measurement error and the like, and other factors. For example, the term “substantially rectangular” is intended to denote structure that is rectangular or approximately rectangular. As another example, the terms “substantially,” “predominately,” “about,” and variations thereof can denote values or characteristics that are exact or within 15% of exact, for example within 10% of exact, or within 3% of exact.

[0042] Provided is a packaging film comprising a single polymer film, a heat sealing coating disposed on one side of the polymer film, and a heat-resistant coating disposed on a second side of the polymer film opposite the first side. In embodiments, the single polymer film is formed from a recyclable polymeric material. The present construction provides a packaging film that can be employed to form a package. In embodiments, the single polymer film is formed from a recyclable polymeric material and still allow for the packaging film to be processed to form a package via heat sealing techniques, such as. for example, in flow wrapping processing.

[0043] Referring to Figures 1 and 2, a packaging film 100 is shown. The packaging film 100 includes a polymer film layer 110, a seal coating 120 disposed on a first side of the polymer film layer 110, and a heat-resistant coating 130 disposed about a second side of the polymer film layer 110. The heat-resistant coating 130 is provided on a side of the polymer film layer that will form the outer surface of a package. The packaging film can optionally include a print layer 140 disposed about the polymer film layer 110 and is ty pically disposed between the polymer film layer 110 and the heat-resistant layer 130.

[0044] The polymer film layer 110 is formed from a single polymer film. The polymer film layer 110 is anon-laminated construction that only includes one polymer film. In embodiments the polymer film layer 110 consists of a single polymer film The material employed to form the polymer lay er 110 is not particularly limited and can be selected from a polymeric as desired for a particular purpose or intended application. Examples of suitable polymeric materials to form the polymer film layer 110 include, but are not limited to, a polyolefin, a polyester, a polyamide, and the like.

[0045] Examples of suitable polyolefins include, but are not limited to polyethylene, polypropylene, polybutylene, and the like. In one embodiment, the polyolefin is selected from polyethylene. The polyethylene is not particularly limited and can be selected from various types of polyethylene include, for example, a high density polyethylene, a medium densitypolyethylene, or a low density polyethylene. It will be appreciated that the polymer film layer can be formed from a blend of polymers, e.g., a blend of different polyolefins, a blend of a particular polyolefin (e.g., a blend of different polyethylenes), and the like.

[0046] Within the polyethylene family, the selection of materials for their thermal transfer properties has a large impact on the ability to successfully seal flexible materials, especially at short dwell times. Properties such as bulk density, specific heat and thermal conductivity determine the final diffusivity of the polymer. The degree of crystallinity plays a role, as the increased orientation of the polymer chains help to transfer heat through the film.

[0047] In one embodiment, the single polymer film comprises high density polyethylene. “High density” polyethylene (HDPE) refers to both (a) homopolymers of densities between about 0.960 to 0.970 g / cm and (b) copolymers of ethylene and an a-olefm (usually 1 -butene or 1-hexene) which have densities between 0.940 and 0.958 g / cnf. High density polyethylene film exhibits high thermal diffusivity, due in part to its increased crystallinity. HDPE, however, tends to not exhibit desirable sealing properties due to its higher melting point. Employing a heat seal coating as opposed to a seal layer of a coextruded film has been found to allow for the entire film to be designed using polymers with superior heat transfer properties.

[0048] Examples of suitable polyester materials include, but are not limited to, polyethylene terephthalate (PET), polyethylene terephthalate glycol (PETG), poly but l one terephthalate (PBT), polyethylene naphthalate (PEN), polyethylene isophthalate (PEI), poly cycloterephthalate (PCT), polytriethylene terephthalate (PT), and the like.

[0049] It will be appreciated that the single polymer film may be a monolayer film or a multilayer film comprising two or more layers. A multi-layer single polymer film may be formed, for example, by co-extrusion of one or more polymeric materials, which may be the same or different from one another. A single polymer film may comprise, in one embodiment, from 1 to 10 layers. The packaging material comprises a single film and does not include two or more, separate films laminated together.

[0050] In one embodiment, the polymer film layer 110 is formed from a recyclable polymeric material. In one embodiment, the polymer film layer 1 10 is formed from a polyolefin material. The polyolefin material can be selected from, for example, the polyolefins descnbed above. In embodiments, the polymer film layer 110 comprises a polyethylene. In one embodiment, the polymer film layer 110 is formed from polyethylene.

[0051] The thickness of the polymer film layer 110 can be selected as desired for a particular purpose or intended application. In embodiments, the polymer film layer 110 has a thickness of from about 18 pm to about 56 pm, from about 20 pm to about 55 pm (from about 0.9 mil to about 2 mil), from about 25 pm to about 45 pm (from about 1 mil to about 1.7 mil), or from about 30 pm to about 40 pm (from about 1.2 mil to about 1.5 mil). In applications employing a polyolefin for the polymer film layer 110, thicknesses on this order may be needed to allow for sufficient heating of the packaging film in a relatively short amount of time without damaging the film.

[0052] The polymer film can be uniaxially machine orientated (MDO) or biaxially oriented. In one embodiment, the polymer film is uniaxially oriented in the machine direction. In one embodiment, the polymer film is biaxially oriented. The degree of stretching, whether uniaxially or biaxially oriented can be selected as desired. In embodiments, a uniaxially stretched film is stretched lx, 1.5x, 2x, 2.5x, 3x, 4x, or 5x. In one embodiment, the polymer film is biaxially oriented and is stretched 1-5 times in the machine direction and 1-5 times in the transverse direction. In one embodiment of a biaxially oriented film, the film is stretched to a greater degree in the transverse direction than in the machine direction. In one embodiment, polymer film is biaxially oriented and is stretched 2-3x in the machine direction and 4-5x in the transverse direction.

[0053] It will be appreciated that the use of oriented polymeric films may provide some level of barrier functionality to the packaging film. Thus the degree of orientation may be useful to build barrier properties into the packaging film structure.

[0054] In still other embodiments, the polymer film may be a non-oriented film. In embodiments the polymer film can be a cast or blown film.

[0055] The seal coating 120 can be provided by any suitable material that allows the packaging film to be bonded to itself or another packaging component (e.g., a separate container) to form a package. The seal coating material may be selected to form sealing bond by any suitable means including heat, pressure, or a combination of heat and pressure.

[0056] Examples of suitable materials for the seal coating include, but are not limited to, heat seal films or heat seal coatings. Examples of heat seal coatings include, but are not limited to, polyester based materials, vinyl / acrylic copolymer based materials, polyolefin based materials, and the like. Some examples of suitable heat sealing materials include, but are not limited to, ethylene vinyl acetate copolymers, low density’ polyethylenes, ionomers, and the like.

[0057] The material for the seal coating may generally be selected such that the seal initiation temperature is below the melting point of the material employed for the polymer layer. The material for the seal layer is selected such that the seal initiation temperature is about 110 °C or lower. In embodiments, the seal layer has a seal initiation temperature of from about 60 °C to about 110 °C, from about 65 °C to about 100 °C, from about 70 °C to about 95 °C, or from about 75 °C to about 90 °C. In one embodiment, the polymer film layer is formed from a polyolefin such as polyethylene or polypropylene.

[0058] The seal coating can be disposed as a continuous layer or discontinuous layer. A discontinuous layer may also be referred to as a patterned layer. The continuous layer may cover substantially the entire surface of the polymer film. In embodiments of a discontinuous seal layer, the seal layer may be disposed in specific regions of the polymer film that will become the seal regions.

[0059] In Figures 1 and 2, the seal coating 120 is provided as a discontinuous layer and is disposed in a pattern such that the seal coating is only provided in those regions of the film that will form the seal. In embodiments where the packaging film is provided as cover layer for acontainer, the heat seal layer may be formed in a pattern corresponding to the shape of the container. In embodiments, where the packaging film is itself employed to form the package, the pattern may generally be such as that shown in Figure 1, where the seal coating is formed in register with the outer edges of the packaging film.

[0060] The seal coating can be applied as a wet layer and then dried. The seal coaitng can be applied by any suitable method including, but not limited to, rotogravure printing.

[0061] The seal coating can be applied in any suitable coat weight so as to provide a suitable seal upon heating. In embodiments, the heat seal layer can be applied in an amount of from about 2 pounds per ream (Ib / R) to about 5 pounds per ream (about 3.2 grams per square meter (GSM) to about 8.2 GSM), from about 2.5 pounds per ream to about 4.5 pounds per ream (about 4 GSM to about 7.3 GSM), or from about 3 pounds per ream to about 4 pounds per ream (about 4.8 GSM to about 6.5 GSM). The levels of sealing material employed in the packaging film are such that the packaging film is still capable of being recycled.

[0062] The seal coating may also be such that the seal provided is a “peelable” seal, i.e., a seal that can be separated manually by a consumer or user, by hand, without the need for a tool.

[0063] The heat-resistant coating 130 allows for heat to be applied to the packaging film without damaging the polymer film layer and provide sufficient heat transfer through the structure to effectuate sealing. At the temperatures employed for heating the heat seal coating, the heat-resistant coating does not melt or get sticky such that the packaging film can still be processed in the package forming operation.

[0064] The heat-resistant coating may be provided by a cross-linked polymer coating, or an over lacquer.

[0065] In one embodiment, the heat-resistant coating may be formed from a lacquer. The lacquer may be selected from one or more polyolefins, polyamides, polyesters, polyester copolymers, polyurethanes, polysulfones, polyvinylidine chloride, styrene-maleic anhydride copolymers, styrene-acrylonitrile copolymers, ionomers based on sodium or zinc salts orethylene methacrylic acid, polymethyl methacrylates, acrylic polymers and copolymers, polycarbonates, polyacrylonitriles, ethylene-vinyl acetate copolymers, and mixtures of two or more thereof. The lacquer can also comprise a diluent or solvent. Examples of suitable solvents / diluents include, but are not limited to. alcohols such as ethanol, isopropanol and butanol; esters such as ethyl acetate, propyl acetate and butyl acetate; aromatic hydrocarbons such as toluene and xylene; ketones such as acetone and methyl ethyl ketone; aliphatic hydrocarbons such as heptane; and mixtures thereof.

[0066] The heat-resistant coating may be radiation curable. The heat-resistant coating may be applied wet, and a solid coating is provided as the material is cured and the solvent is flashed off.

[0067] In one embodiment, the heat-resistant coating may be provided by a radiation curable polymer coating. In embodiments, the radiation curable coating may be cured via electron beam. The radiation curing may provide a crosslinked coating layer. In one embodiment, the heat-resistant layer may be provided by a composition comprising a mixture of oligomers and monomers. The radiation curable polymer coating generally comprises an ethylenically unsaturated compound comprising one or more double bonds. In embodiments, the ethylenically unsaturated compound comprises at least two double bonds. Examples of ethylenically unsaturated compounds include, but are not limited to, ethylenically unsaturated monomer, ethylenically unsaturated oligomer, ethylenically unsaturated polymer, or mixtures of two or more thereof. Examples of ethylenically unsaturated compounds include, but are not limited to, an acrylate, a methacrylate, an epoxy, a rosin ester, a hydrocarbon resin, a vinyl compound, a polyvinyl pyrrolidone compound, a polyvinyl pyrrolidone containing copolymer, a styrene maleic anhydride compound, a urethane compound, or combinations thereof. Examples of particularly suitable compounds include, but are not limited to, epoxy acrylates, polyether acrylates, polyurethane acry lates, polyester acrylates, and ethoxylated or propoxylated di- or multi-functional acry lates; polyesters of ethylenically unsaturated acidssuch as acrylic acid and methacrylic acid and a polyhydric alcohol. Examples of polyfunctional compounds include, but are not limited to, the polyacrylates and polymethacrylates of trimethylolpropane, pentaerythritol, dipentaerythritol, ethylene glycol, triethylene glycol, propylene glycol, glycerin, sorbitol, neopentylglycol. 1,6-hexanediol and hydroxy-terminated polyesters, hydroxy-terminated epoxy resins, and hydroxy-terminated polyurethanes. Examples of suitable terminally unsaturated organic compounds include, but are not limited to, polyallyl and polyvinyl compounds such as diallyl phthalate and tetraallyloxy ethane and divinyl adipate, butane di vinyl ether and divinylbenzene. Further examples include, but are not limited to, acrylates of primary or polyhydric alcohol or oligoacrylates such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, hydroxyethyl acrylate, 2-ethylhexyl acrylate, ethylene glycol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, epoxy acrylates, oligoester acrylates, urethane acrylates, and the like. Still further examples include, but are not limited to, methacrylates of primary or polyhydric alcohol such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, hydroxyethyl methacrylate, 2-ethylhexyl methacrylate, diethylene glycol di methacryl ate. trimethylolpropane trimethacrylate, and the like, or allyl alcohol, diallyl ether, diallyl adipate, dially 1 phthalate, both end diallylates of low molecular weight polyurethane, and the like. In one embodiment, the radiation curable polymer coating comprises an epoxy acry late oligomer and an acry late monomer.

[0068] Additional additives can be incorporated into the formulation to improve qualities such as the gloss, COF, scuff resistance, heat resistance, modulus, and processing.

[0069] The electron beam coating is cured using a suitable electron beam source. The amount of energy7absorbed, also known as the dose, is measured in units of MegaRads (MR or Mrad) or kiloGrays (kGy). One Mrad is equal to 10 kGy, and one kGy' is equal to 1,000 Joules per kilogram. In embodiments, the radiation curable heat-resistant coating is cured by' exposing the composition to an electron beam dose within the range of from about 10 kGy to about 40 kGy.

[0070] The heat-resistant coating 130 can be provided at a coating weight of from about 0.5 Ib / R to about 2.5 Ib / R (about 0.8 GSM to about 4 GSM), from about 0.75 Ib / R to about 2 Ib / R (about 1.2 GSM to about 3.3 GSM), or from about 1 Ib / R to about 1.5 Ib / R (from about 1.6 GSM to about 2.4 GSM).

[0071] The packaging film may optionally include a barrier layer. The barrier layer may be employed to function as a barrier to moisture (to reduce the moisture vapor transmission rate) and / or as a barrier to a diffusive species (e.g.. a gas such as. for example, oxygen, carbon dioxide, an aroma, etc.). The term "‘diffusive species” is used interchangeable with the term “gas”. The barrier layer can be selected as desired for a particular purpose or intended use. For example, intended applications of a film may require or beneficially have low moisture vapor transmission rates and / or low diffusion rates of a diffusive species.

[0072] The barrier layer may be disposed on either side of the polymer film layer. That is, the barrier layer may be disposed toward the exterior of the package formed from the packaging film or the interior of the package formed from the packaging film. Depending on the type of material used for the barrier layer, it may be desirable to have the barrier layer disposed about a surface of the polymer film layer that will become the exterior of the package formed from the packaging film. In particular, it may be desirable to not have the barrier layer exposed to or in potential contact wi th the products to be contained within the package.

[0073] The thickness of the barrier layer may be selected as desired, in conjunction with the material selected, to provide the desired barrier properties. In embodiments, the barrier layer may have a thickness of from about 100 angstroms to about 50 pm, from about 250 angtroms to about 25 pm, from about 500 angstroms to about 10 pm, or from about 1000 angstroms to about 1 pm.

[0074] The barrier layer can be selected from any suitable material for functioning as a moisture barrier and / or a gas barrier. Examples of suitable materials to form the barrier layer include, but are not limited to, a metal (e.g., a metal coating), an oxide layer, a nanoclay, apolymeric barrier layer, and the like. The barrier layer can be provided as a single layer or may be provided with multiple layers of barrier material(s). In one a multi-layer barrier layer, the respective barrier layers may be formed from the same or different materials. For example, the barrier layer may include a metal layer and a metal oxide layer; a metal layer and layer of polymeric material; a metal layer and a nanoclay layer; etc. The combinations may be selected to provide a particular barrier property, e.g., moisture barrier, gas barrier, or combination thereof.

[0075] In one embodiment, the barrier layer comprises a metal layer. A metal layer can be provided as a layer of thin metal on the polymer film layer. The metal can be selected as desired. Examples of suitable metals include, but are not limited to, aluminum, nickel, chromium, and the like. In embodiments, the metal layer is provided at a thickness of less than 1 micron, less than 0.75 micron, less than 0.5 micron. In embodiments, the metal layer is provided at a thickness of from about 0. 1 micron to about 0.5 micron. Where the packaging film is to be provided as a recyclable package, the amount of metal in the packaging film may need to be kept relatively low concentration.

[0076] The metal coating layer can be provided in any suitable manner. In one embodiment, the metal coating layer can be provided as a foil and bonded or adhered to the polymer film layer. In another embodiment, the metal coating layer can be deposited on the polymer film layer via any suitable method such as, but not limited to, sputtering, vacuum deposition, and the like.

[0077] In another embodiment, the barrier layer is selected from an oxide coating layer. Examples of suitable materials for the oxide coating include, but are not limited to, an aluminum oxide, a silicon oxide, a mixed metal oxide, and the like. Examples of suitable mixed metal oxides include, but are not limited to, metal-silicon-oxides, where the metal is selected from aluminum, titanium, zinc, and the like. Oxide coatings may be particularly useful inpackages that are to be recyclable and / or in larger packages (e.g., packages having a surface area of over 100 in2.

[0078] In embodiments, the barrier layer comprises a nanoclay. Examples of suitable nanoclays include, but are not limited to. montmorillonites, bentonite, vermiculite platelets, hallosite, cloisite, smectite, or a combination of two or more thereof.

[0079] Polymeric material suitable for the barrier layer include, but are not limited to, polyethylene terephthalate (PET), amorphous polyethylene terephthalate (APET), oriented polyethylene terephthalate (OPET), polyamide (PA), amorphous polyamide (APA). oriented polyamide (OP A), ethylene vinyl alcohol copolymer (EV OH), polyvinyl alcohol (PVOH), or combinations of two or more thereof. In one embodiment, the barrier layer comprises a polymeric material selected from EVOH, PVOH, or a combination thereof.

[0080] In configuring the packaging film, the barrier layer may be disposed adjacent to the polymer film layer. The barrier layer can be disposed on the upper side of the polymer film (i.e., oriented toward what will be the exterior of the packaging film) or on the lower side of the polymeric film (i.e., oriented toward what will be the interior of the packaging film when formed into a package).

[0081] Figure 3 is an example of an embodiment where the packaging film 200 contains a barrier layer 150 disposed on a surface of the polymer film 110. The print layer / indicia can be printed onto the barrier layer 140, and the heat-resistant layer 130 is disposed over the print layer. In one embodiment, the barrier layer is a metal layer. In another embodiment, the barrier layer is an oxide coating layer.

[0082] Figure 4 is an embodiment of a packaging film 300 comprising a polymer film layer 110, a heat-resistant coating layer 130, a print layer 140, and a heat seal layer 120. The heat seal layer 120 is disposed as a continuous layer on the underside of the polymer film layer 110. The film 300 further comprises a barrier layer 150 disposed between the surface of the polymer film 110 and the heat seal layer 120.

[0083] Figure 5 is an embodiment of a packaging film 400 comprising a polymer film layer 110, a heat seal layer 120, a heat-resistant coating 130, a print layer 140, and a barner layer 150. The barrier layer 150 is a multi-layer barrier layer having layers 152 and 154. Barrier layers 152 and 154 can be formed from different materials. In one embodiment, layer 154 is a polymeric barrier material, and layer 152 is a metal layer. In one embodiment, layer 154 is formed from EV OH. PV OH, or a combination thereof.

[0084] In one embodiment, the packaging film consists essentially of or consists of a single layer of a polymer film, a heat sealing layer disposed on one side of the polymer film, a heat- resistant layer disposed on a second side of the polymer film opposite the first side, and an optional print layer. In embodiments, the polymer film is polyethylene.

[0085] In one embodiment, the packaging film consists essentially of or consists of a single layer of a polymer film, a heat sealing layer disposed on one side of the polymer film, a heat- resistant layer disposed on a second side of the polymer film opposite the first side, an optional print layer, and a barrier layer disposed between the heat-resistant layer and the polymer film.

[0086]

[0087] The packaging films can be employed to form a package product or can be employed as a component (e.g., a cover or lid) of a package product. The packaging film may be used in any sort of package form such as, but not limited to, a pouch, a bag, flow wrap, tray / lid, chub, bulk bag, blister pack, and the like. In embodiments, the packaging film may be used to form a package in a horizontal flow wrapping operation. In one embodiment, the packaging film may be employed in a vertical form fill seal bagging operation. Packaging films in accordance with the present technology that include a non-oriented single polymer film may be suitable for use in vertical form fill seal bagging operations.

[0088] In one embodiment, the packaging film can be sealed to itself to form a package. Referring to Figure 1 , for example, the vertical edges may be brought together to form a “spine” such as with a fin seal and define a tube or interior cavity surrounding an item to be housed inthe package. The ends of the package are then each crimped together to seal the ends and form the package.

[0089] In one embodiment, the packaging film is employed as a cover or hd for a container. The container may be, for example, a tray, cup, or the like. The container material is not particularly limited and can be selected as desired. The container material may be. for example, flexible, semi-rigid, or rigid. Examples of suitable materials for a container include, but are not limited to. polyester, polyolefin (e.g., polyethylene, polypropylene, etc.), polystyrene, polyvinyl chloride, paper, metal, glass, ceramic, and the like. The container will typically have an upper surface, and the package film is sealed to the upper surface of the container. The package film is sealed to the container such that the package film can be peeled away from the container body to expose the contents of the container.

[0090] In one embodiment, the packaging film can be employed to form a bag, pouch, or sachet. Such configurations are generally formed from multiple sheets of packaging film brought together to form the w alls of the package. A pouch or bag may be sealed in a fin seal or lap seal configuration. A sachet may have side seals and end seals. Fitments or other closures may be sealed to any part of the recyclable film. The packaging can be formed from any suitable now known or later discovered packaging method. Examples of suitable methods for forming packaging include, but are not limited to, vertical form / fill / seal (VFFS), horizontal form / fill / seal (HFFS), thermoforming / lidstock, and continuous horizontal packaging. It will be appreciated that those skilled in the art will be capable of employing the present packaging film to provide the necessary conditions to form the shape of the packaging and effect sealing.

[0091] Figure 6 is an embodiment of package formed from a packaging film 100 where edges of the film have been j oined to form a luminal space 118 in w hich a product can be stored and protected from the elements after the two packaging films are sealed together at the seal layer 120, forming a package. The luminal space 118 can also be filled with an inert gas such as nitrogen, or a liquid.

[0092] The packaging film can be used to package any type of product. Examples of suitable products include, but are not limited to, foods, beverages, pharmaceuticals, nutraceuticals, cosmetics, medical products, electronic devices and products, wipes, etc. Examples of food products that can be packaged using the packaging films include, but are not limited, dry foods, frozen foods, fresh foods, refrigerated foods, and the like. Examples of food products include but are not limited to, cereals, chips, pretzels, bars (e.g., candy bars, protein bars, granola bars, etc.), nuts, raisins, pizzas, tortillas, gum. popcorn, a grain, a seasoning, popsicles, a frozen bar, ready-to-bake dough, pet food, vegetables, fruits, meats, cheese, sugar and powders, candy, and the like.

[0093] Examples

[0094] Lamination Versus Single Film

[0095] The sealing performance of films employing a single layer film in accordance with embodiments and aspects of the present technology were compared to films employing conventional multi-layer laminate polymer films. Trials were conducted on a vertical bagger with a short dwell time of 50ms. Seal windows were established by determining the minimum temperature at which the material would seal (the bottom end of the seal window) and the maximum temperature at which the material could be sealed (the top end of the seal window) without degrading the material, sticking to the seal jaws, etc. The widths of the seal windows were then compared. The comparative examples employed conventional traditional allpolyethylene laminations, a high performance all-polyethylene lamination, and the inventive examples employed two single film (non-laminated) embodiments with an over print varnish (lacquer).

[0096] The films can be identified as follows:

[0097] Comparative Example 1 : 90ga MDOPE 1 / 1.25 mil HDPE-EVA (Vendor 1 MDOPELamination 1)

[0098] Comparative Example 2: 90ga MDOPE 2 / 1 mil HDPE-metallocene (Vendor 1 MDOPE Lamination 2)

[0099] Comparative Example 3: 90ga MDOPE 2 / 1.25 mil HDPE-EVA (Vendor 1 MDOPE Lamination 3)

[0100] Comparative Example 4: 1.0 mil High Performance MDOPE / adh / 1.25 mil White HDPE-EVA (Vendor 2 MDOPE Lamination)

[0101] Comparative Example 5: 0.75mil MDOPE / ink / adh / 1.25mil white HDPE-mLLDPE Coex

[0102] Example 1 : OPV / ink / 96ga BOPE / HSC

[0103] Example 2: OPV / ink / 150ga MDOPE 1 / HSC

[0104] The films were tested and compared against the estimated seal window needed, indicated as the seal window target on the chart in FIG. 7. The summary of the results is shown in Table 1.

[0105] Table 1

[0106] The single film materials outperformed all laminations in this test. FIG. 7 includes an entry for a PET film. It is noted that the PET lamination used on the product in question was not tested and the seal window shown is an estimate.

[0107] E-Beam Coated Films

[0108] This trial was conducted on a horizontal flow wrapper at a rate of 400 packages / minute. Two polyethylene materials were compared: one with a lacquer conventionally cured, and one with an E-beam lacquer. The maximum temperature which each material could withstand was measured. Failure was determined by excess material deformation, melting of the material, cut through of the material and / or sticking to the seal jaws.

[0109] Table 2 and FIG. 8 shows the results of the trial.

[0110] Table 2

[0111] The film with the convention lacquer provides good heat resistance. The material utilizing the E-beam lacquer (Example 4) performed even better demonstrated by the 15 degrees Celsius increase in heat resistance compared to Example 3.

[0112] What has been described above includes examples of the present specification. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the present specification, but one of ordinary skill in the art may recognize that many further combinations and permutations of the present specification are possible. Accordingly, the present specification is intended to embrace all such alterations, modifications and variations that fall within the spirit and scope of the appended claims. Furthermore, to the extent that the term “includes” is used in either the detailed description or the claims, such term is intended to be inclusive in a manner similar to the term “comprising” as “comprising” is interpreted when employed as a transitional word in a claim.

[0113] The foregoing description identifies various, non-limiting embodiments of a packaging film, methods of making a packaging film, and packaging and packaged products employing such packaging films. Modifications may occur to those skilled in the art and to those who may make and use the invention. The disclosed embodiments are merely for illustrative purposes and not intended to limit the scope of the invention or the subject matter set forth in the claims.

Claims

CLAIMSWhat is claimed is:

1. A packaging film, comprising:(a) a single polymer film having a first surface and an opposing second surface;(b) a seal layer disposed on the first surface of the single layer polymer film layer; and(c) a heat-resistant layer disposed about the second surface of the single layer polymer film layer2. The packaging film of claim 1, wherein the single polymer film comprises a polyolefin.

3. The packaging film of claim 2, wherein the polyolefin is selected from polyethylene.

4. The packaging film of claim 2 or 3, wherein the polyolefin is selected from high density polyethylene.

5. The packaging film of any of claims 1 to 4, wherein the single polymer film is biaxially oriented.

6. The packaging film of any of claims 1 to 4, wherein the single polymer film is machine direction oriented.

7. The packaging film of any of claims 1 to 6 further comprising a barrier layer.

8. The packaging film of claim 7, wherein the barrier layer is disposed between the single polymer film and the heat-resistant layer.

9. The packaging film of claims 7 or 8, wherein the barrier layer comprises a metal, an oxide, a nanoclay, or a polymeric material.

10. The packaging film of any of claims 1 to 9, wherein the heat-resistant coating is selected from a lacquer.

11. The packaging film of any of claims 1 to 9, wherein the heat-resistant coating is selected from a radiation curable polymer.

12. The packaging film of any of claims 1 to 9. wherein the single layer polymer film layer has a thickness of from about 18pm to about 56pm.

13. The packaging film of any of claims 1-12, wherein the seal layer has a seal initiation temperature of about 110 °C or lower.

14. The packaging film of any of claims 1 to 12, wherein the seal layer has a seal initiation temperature of from about 60 °C to about 110 °C.

15. The packaging film of any of claims 1 to 14, wherein the packaging film is recyclable.

16. A package comprising the packaging film of any of claims 1 to 15.

17. The package of claim 16, wherein the package is formed from packaging film.18 The package of claim 16 comprising a container and a cover, the container having a bottom member, one or more side walls extending from the bottom member and defining a package interior and an opening adjacent an upper end of the one or more side walls, and wherein the cover is disposed along the upper end of the one or more side w alls, and the cover is formed from the packaging film.

19. The package of any of claims 16 to 18 comprising a food product disposed within the package.