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WO2025188673A1 - Film d'emballage multicouche à couche polymère compatibilisée - Google Patents

Film d'emballage multicouche à couche polymère compatibilisée

Info

Publication number
WO2025188673A1
WO2025188673A1 PCT/US2025/018222 US2025018222W WO2025188673A1 WO 2025188673 A1 WO2025188673 A1 WO 2025188673A1 US 2025018222 W US2025018222 W US 2025018222W WO 2025188673 A1 WO2025188673 A1 WO 2025188673A1
Authority
WO
WIPO (PCT)
Prior art keywords
film
packaging film
ethylene
outer film
layer
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/US2025/018222
Other languages
English (en)
Other versions
WO2025188673A8 (fr
Inventor
Otacilio T. Berbert
Brett P. Bobko
Jeremy C. REEDY
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Amcor Flexibles North America Inc
Original Assignee
Amcor Flexibles North America Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Amcor Flexibles North America Inc filed Critical Amcor Flexibles North America Inc
Publication of WO2025188673A1 publication Critical patent/WO2025188673A1/fr
Publication of WO2025188673A8 publication Critical patent/WO2025188673A8/fr
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
    • B32B27/08—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/28—Layered products comprising a layer of synthetic resin comprising synthetic resins not wholly covered by any one of the sub-groups B32B27/30 - B32B27/42
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/30—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers
    • B32B27/302—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers comprising aromatic vinyl (co)polymers, e.g. styrenic (co)polymers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/32—Layered products comprising a layer of synthetic resin comprising polyolefins
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D65/00—Wrappers or flexible covers; Packaging materials of special type or form
    • B65D65/38—Packaging materials of special type or form
    • B65D65/40—Applications of laminates for particular packaging purposes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2255/00—Coating on the layer surface
    • B32B2255/10—Coating on the layer surface on synthetic resin layer or on natural or synthetic rubber layer
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2255/00—Coating on the layer surface
    • B32B2255/20—Inorganic coating
    • B32B2255/205—Metallic coating
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/50—Properties of the layers or laminate having particular mechanical properties
    • B32B2307/514—Oriented
    • B32B2307/516—Oriented mono-axially
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/50—Properties of the layers or laminate having particular mechanical properties
    • B32B2307/514—Oriented
    • B32B2307/518—Oriented bi-axially
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/70—Other properties
    • B32B2307/732—Dimensional properties
    • B32B2307/737—Dimensions, e.g. volume or area
    • B32B2307/7375—Linear, e.g. length, distance or width
    • B32B2307/7376—Thickness
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2439/00—Containers; Receptacles

Definitions

  • the present application relates to packaging films and packaged products made therefrom.
  • the packaging film comprises a structure and composition aimed at recycling ease.
  • Packaging films are widely used in various industries for the purpose of protecting and preserving goods during storage and transportation. These films are typically composed of multiple layers to provide the desired properties such as strength, flexibility, and barrier properties.
  • One common approach in the prior art has been to use polypropylene as the main material for the outer films of the packaging film.
  • Polypropylene is known for its excellent mechanical properties, including high tensile strength and impact resistance, making it suitable for packaging applications.
  • Typical snack packaging consists of oriented polypropylene (OPP) based packaging films.
  • OPP oriented polypropylene
  • the packaging films are very thin, having high gloss graphics for retail attraction, and excellent sealing properties. These films provide protection to snack foods over the storage and distribution cycle. Additionally, the films are capable of running extremely fast on packaging lines.
  • a polymer layer is typically utilized.
  • Previous approaches have utilized various types of polymers for this purpose.
  • some prior art packaging films have used polyethylene as the polymer layer, as it can provide good adhesion between the polypropylene outer films.
  • the present disclosure includes descriptions of packaging films and the use of these packaging films to make packages for packaged products.
  • the techniques described herein relate to a packaging film including: a first outer film including polypropylene; a second outer film including polypropylene; and a polymer layer connecting the first outer film and the second outer film; wherein the polymer layer includes a compatibilizer selected from a group consisting essentially of a propylene/ethylene copolymer, a 1 -butene rich 1-butene/ethylene plastomer, a polypropylene heterophasic olefin copolymer, an olefin block copolymer, a hydrogenated styrene-butadiene- styrene block copolymer, an ethylene propylene rubber, an ethylene propylene diene monomer and a combination thereof.
  • a compatibilizer selected from a group consisting essentially of a propylene/ethylene copolymer, a 1 -butene rich 1-butene/ethylene plastomer, a polypropylene heterophasic olefin cop
  • the polymer layer further includes a stabilizer selected from a group consisting essentially of a homogeneously branched linear ethylene polymer, a heterogeneously branched linear ethylene polymer and a combination thereof.
  • the techniques described herein relate to a packaging film, wherein each of the first outer film and the second outer film are independently biaxially oriented or monoaxially oriented.
  • the techniques described herein relate to a packaging film, wherein the first outer film has a first outer film composition including polypropylene in a range of from 80% to 100%, by weight, and a thickness in a range of from 5 microns to 35 microns.
  • the techniques described herein relate to a packaging film, wherein the second outer film has a second outer film composition including polypropylene in a range of from 80% to 100%, by weight, and a thickness in a range of from 5 microns to 35 microns.
  • the techniques described herein relate to a packaging film, wherein the packaging film has a packaging film composition including polypropylene in a range of from 30% to 90%, by weight.
  • the techniques described herein relate to a packaging film, wherein the polymer layer further includes low-density polyethylene.
  • the techniques described herein relate to a packaging film, wherein the polymer layer includes a first sub-layer, a second sub-layer, and a third sub-layer, and the second sub-layer is located between the first sub-layer and the third sub-layer.
  • the first sub-layer is adjacent to the first outer film
  • the third sub-layer is adjacent to the second outer film
  • at least one of the first sub-layer and the third sub-layer include at least one of low-density polyethylene and non-neutralized ethylene acid copolymer.
  • the second sub-layer includes the compatibilizer.
  • the techniques described herein relate to a packaging film, wherein the packaging film has a packaging film composition including compatibilizer in a range of from 10% to 35%, by weight.
  • the compatibilizer is a propylene-rich propylene/ethylene copolymer.
  • the compatibilizer is a propylene/alpha-olefin copolymer.
  • the techniques described herein relate to a packaging film, wherein the stabilizer is a homogeneously branched linear ethylene polymer.
  • the stabilizer is an ethylene/hexene copolymer or an ethylene/octene copolymer.
  • the techniques described herein relate to a packaging film having a thickness in a range of from 15 micron to 100 micron.
  • the techniques described herein relate to a packaging film adapted for recycling in a polyolefin recycling stream, the packaging film including: a first outer film including at least 80% polypropylene, by weight; a second outer film including at least 80% polypropylene, by weight; and a polymer layer connecting the first outer film and the second outer film; wherein the polymer layer includes a compatibilizer selected from a group consisting essentially of a propylene/ethylene copolymer, a 1 -butene rich 1-butene/ethylene plastomer, a polypropylene heterophasic olefin copolymer, an olefin block copolymer, a hydrogenated sty rene-butadiene- styrene block copolymer, an ethylene propylene rubber, ethylene propylene diene monomer rubber, and a combination thereof; wherein the polymer layer includes a stabilizer selected from the group consisting essentially of a homo
  • the techniques described herein relate to a packaging film, further including a metallization layer located on a surface of the second outer film.
  • the packaging film includes ink located between the first outer film and the polymer layer.
  • the packaging film has a thickness in a range of from 15 micron to 100 micron.
  • the techniques described herein relate to a packaging film, the packaging film composition includes the first outer film and the second outer film in a range of from 30% to 80%, by weight.
  • the techniques described herein relate to a packaging film adapted for recycling in a polyolefin recycling stream
  • the packaging film including: a first outer film including a biaxially oriented polypropylene film; a second outer film including a biaxially oriented polypropylene film; a polymer layer connecting the first outer film and the second outer film; and a metallization layer located on a surface of the second outer film, the metallization layer located between the second outer film and the polymer layer; wherein the polymer layer includes at least one of a compatibilizer and a stabilizer; and wherein the compatibilizer is selected from a group consisting essentially of a propylene/ethylene copolymer, a 1 -butene rich 1-butene/ethylene plastomer, a polypropylene heterophasic olefin copolymer, an olefin block copolymer, a hydrogenated styrene-butadiene-styrene block copoly
  • the techniques described herein relate to a packaging film wherein the packaging film is recyclable in a polyethylene recycle stream by having comparable physical properties when blended 50/50% with control PE such as tear, impact, and tensile & elongation (according to APR Critical Guidance test protocol).
  • control PE such as tear, impact, and tensile & elongation
  • Examples include snacks and confectionary packaging typically commercialized as bags, pillow packs, pouches or flow-wraps.
  • the techniques described herein relate to a packaging film, wherein the compatibilizer is selected from a group consisting essentially of a propylene/ethylene copolymer, a polypropylene heterophasic olefin copolymer, an ethylene propylene rubber, an ethylene propylene diene monomer and a combination thereof.
  • the techniques described herein relate to a packaged product including: a packaging film, and a product; wherein the packaging film is sealed to form a package and the product is enclosed within the package.
  • the techniques described herein relate to a packaged product including: a packaging film sealed to form a package and a product enclosed within the package, the packaging film including: a first outer film including polypropylene; a second outer film including polypropylene; and a polymer layer connecting the first outer film and the second outer film; wherein the polymer layer includes a compatibilizer selected from a group consisting essentially of a propylene/ethylene copolymer, a 1 -butene rich 1-butene/ethylene plastomer, a polypropylene heterophasic olefin copolymer, an olefin block copolymer, a hydrogenated styrene-butadiene- styrene block copolymer, an ethylene propylene
  • the techniques described herein relate to a packaged product wherein the package is in the form of a pillow pack including two end seals and a seam, the seam formed as a fin seal or as a lap seal.
  • FIG. 1 is a cross-sectional view of an embodiment of a packaging film as described herein.
  • FIG. 2 is a cross-sectional view of an embodiment of a polymer layer of a packaging film as described herein.
  • FIG. 3 is a cross-sectional view of an embodiment of a packaging film as described herein.
  • FIG. 4 is a perspective view of an embodiment of a packaged product as described herein.
  • the present disclosure includes descriptions of packaging films and the use of these packaging films to make packages for packaged products.
  • the unique film structures and formulas discussed herein the inventors have surprisingly found that the common BOPP/BOPP laminate structure used as an economical solution for snack packaging can be made recyclable in the polyolefin recycling stream.
  • the new structures have strategically improved recyclability while maintaining appearance, barrier performance, low cost, production ease and packaging line speeds.
  • snack packaging that utilizes oriented polypropylene laminates has the distinct problem of end-of-life processing.
  • the current structure is not recyclable into the preferred polyethylene recycling stream and efforts to move the structure into a compostable/biodegradable solution have been unsuccessful.
  • the end-of-life option for the current structures is typically a waste stream.
  • Other structure options that might avoid the waste stream, such as those made using compostable materials, have not achieved adequate performance and/or cost to make these solutions feasible to the packaging industry.
  • a ground-breaking solution including a structure with nearly identical performance to current solutions, but now including the ability to be accepted into a widely available polyethylene recycling stream.
  • the inclusion of a polymer layer containing a compatibilizer and optionally a stabilizer, as will be fully discussed herein, allows for the advancement of this packaging type that was previously unknown.
  • the packaging films described herein include significant proportions (z.e., greater than 30%, 40%, 50% or 60%) of polypropylene.
  • Polypropylene is immiscible in polyethylene and therefore is generally not acceptable to add into the polyolefin recycling stream which includes melting and blending the incoming polymer materials.
  • Development by the inventors resulted in the surprising effect that packaging film structures including significant proportions of polypropylene can be rendered recyclable in the polyolefin recycling stream (i.e., both the polyethylene and polypropylene recycling streams) by including specific compatibilizers into the structure.
  • immiscible polymer blends depend on factors like the droplet sizes of the dispersed (minor) phase and interfacial adhesion. When droplet sizes are large, resultant light scatter can reduce the transparency of the blend. Low interfacial adhesion can reduce strength properties and promote cavitation during deformation operations like thermoforming and uniaxial or biaxial stretching.
  • An immiscible polymer can cause the articles made from the polymer blend to have less desirable appearance and/or mechanical properties. To improve transparency and strength, it is often desirable to maintain a stabilized distribution of small droplets in a multiphase polymer blend.
  • thermodynamically immiscible polymers are blended in a mixing device and elongational stresses exceed the elastic limits of the minor polymer fractions, those minor fractions break into droplets which become the dispersed phase of the multiphase system.
  • the mixing device can utilize moving elements (e.g. , extruder) or it can be stationary (e.g., static mixer).
  • the deformation and break-up of viscous droplets in a flow field are governed by the capillary number (C a ).
  • the capillary number compares the relative strengths of the viscous stress (tends to cause droplet elongation) and the interfacial stress (a surface tension effect which tends to make the droplet spherical).
  • the capillary number reaches a critical value, the viscous stress dominates, and the interfacial stress is insufficiently large to prohibit droplet break-up. That is, surface tension can no longer maintain a spherical droplet, so the droplet elongates and eventually ruptures into smaller units.
  • a compatibilizer prevents coalescence of dispersed droplets and maintains a stable, multi-phase polymer system.
  • the term “recyclable” is meant to indicate that the film can be converted into a new useful item by means of reprocessing in a polyolefin recycling stream. Reprocessing may entail washing, separating, melting and forming, among many other steps. Typically, when plastic packaging is reprocessed, the material is mechanically chopped into small pieces and then melted to be reformed into the new product. If multiple incompatible materials are present in the packaging, interactions occur during reprocessing causing gels, brittle material, poor appearance and generally un-usable or poor-quality products. Using the term “recyclable” indicates that these drawbacks are generally not present.
  • Recyclable films disclosed herein may be suitable for “Store Drop-off” recycling streams. These streams may accept the following: 100% polyethylene bags, wraps, and films; very close to 100% polyethylene bags, wraps, and How2Recycle-approved polyethylene-based carrier packing with or without compatiblizer technology. Introduction of a recyclable film into any of these recycling-by-reprocessing avenues should not require additional compatibilizer.
  • polyolefin recycling stream refers to an industrial process of reprocessing resulting in a product that can be reformed into a new product.
  • a polyolefin recycling stream may be dedicated to polyethylene (z.e., a polyethylene recycling stream), polypropylene (z.e., a polypropylene recycling stream) or blends of polyolefins.
  • the packaging films disclosed herein may be free from materials that contaminate the polyolefin recycling stream.
  • the packaging films may be free from polyamide (PA), ethylene vinyl alcohol copolymer (EVOH) and/or metal foils (z.e., aluminum foil having thickness above 5 micron).
  • PA polyamide
  • EVOH ethylene vinyl alcohol copolymer
  • metal foils z.e., aluminum foil having thickness above 5 micron.
  • PA and EVOH may be present but at a low level, such as below 5%, by weight of the entire packaging film.
  • the term "film” refers to a web built of one or more layers and/or films, all of which are directly adjacent to and connected to each other.
  • a film can be described as having a thickness that is insignificant as compared to the length and width of the film.
  • a film has two major surfaces, the area of which are defined by the length and width of the film.
  • the term "layer” refers to refers to a building block of a film.
  • a polymer layer may have a composition that is a single material type or a homogeneous blend of materials.
  • a layer may be a single polymer, a blend of materials within a single polymer type or a blend of various polymers, may contain metallic materials and may have additives.
  • Layers may be continuous with the film or may be discontinuous or patterned.
  • a layer has an insignificant thickness (z direction) as compared to the length and width (x-y direction), and therefore is defined to have two major surfaces, the area of which are defined by the length and width of the layer.
  • An exterior layer is one that is connected to another layer at only one of the major surfaces. In other words, one major surface of an exterior layer is exposed.
  • An interior layer is one that is connected to another layer at both major surfaces. In other words, an interior layer is between two other layers.
  • a layer may have sub-layers. As used herein, the term "sublayer" refers to homogeneous layer within a layer.
  • the term "packaging film” refers to a film capable of being formed into a package.
  • the packaging film may be flexible.
  • a flexible packaging film may be bent or flexed into a shape and then bonded to itself or other packaging components such that a cavity is formed and generally retains the shape.
  • a product may be contained in the cavity.
  • a packaging film may be capable of forming hermetic seals and may provide oxygen and/or moisture barrier properties.
  • a packaging film has two exterior surfaces defined by a length and a width.
  • Figure 1 shows a cross-sectional view of an embodiment of a packaging film 102 including a first outer film 104, a second outer film 106 and a polymer layer 108 connecting the first outer film 104 to the second outer film 106.
  • the polymer layer 108 is between the first outer film 104 and the second outer film 106.
  • the polymer layer 108 may be in direct contact with the first outer film 104.
  • the polymer layers 108 may be in direct contact with the second outer film 106.
  • the first outer film 104, the second outer film 106 and the polymer layer 108 may be fully coextensive with each other.
  • a thin primer may be applied to the surface of the first outer film to aid in the adhesion of the polymer layer to the first outer film.
  • the first outer film may be an outer layer of the packaging film and may be an exterior layer of the packaging film.
  • outer layer refers to one or more layers of a film that are on either major surface of the film, i.e., the layers that are not between two other layers of that film.
  • the term “exterior” is used to describe a film, layer or surface that is located in an outer layer position such that it is at or near the surrounding environment when the film is used in a packaging application.
  • the second outer film may be an outer layer of the packaging film and may be an interior layer of the packaging film.
  • the term “interior” is used to describe a film, layer or surface that is located in an outer layer position such that it is at or near the packaged product when the film is used in a packaging application.
  • Each of the first outer film and the second outer film may comprise polypropylene.
  • the composition of the first outer film and the second outer film may independently be in the range of from 50% to 100% polypropylene, from 60% to 100%, from 70% to 100%, from 80% to 100% or from 90% to 100%, by weight.
  • the first outer film may comprise at least 80% or at least 90% polypropylene.
  • the second outer film may comprise at least 80% or at least 90% polypropylene.
  • a composition of polypropylene is understood to include the weight of any polymer or copolymer that includes greater than 50% propylene linkages (i.e., propylene-rich copolymers or terpolymers). For example, included in the polypropylene weight would be homopolymer polypropylene and random polypropylene copolymers.
  • the remaining portion may be a polyolefin such as polyethylene.
  • the composition of the first outer film and/or the second outer film may include one or more of the compatibilizers disclosed herein.
  • the composition of the first outer film and/or the second outer film may include one or more of the stabilizers disclosed herein.
  • the first outer film and/or the second outer film may be transparent or opaque.
  • the first outer film and/or the second outer film may be white due to an added pigment, such as titanium dioxide particles, or cavitation.
  • the first and second outer films may be oriented.
  • Orientation may be the result of monoaxially oriented (machine direction or transverse direction), or biaxially oriented (machine direction and transverse direction) stretching of the film, increasing the machine direction and/or transverse direction dimension and subsequently decreasing the thickness of the material.
  • Biaxial orientation may be imparted to the film simultaneously or successively. Stretching in either or both directions is subjected to the film in the at a temperature just below the melt temperature of the polymers in the film. In this manner, the stretching causes the polymer chains to “orient”, changing the physical properties of the film. At the same time, the stretching thins the film.
  • the resulting oriented films are thinner and can have significant changes in mechanical properties such as toughness, heat resistance, stiffness, tear strength and barrier.
  • Orientation is typically accomplished by a double- or triple-bubble process, by a tenter-frame process or an MDO process using heated rolls.
  • a typical blown film process does impart some stretching of the film, but not enough to be considered oriented as described herein.
  • An oriented film may be heat set (z.e. annealed) after orientation, such that it is relatively dimensionally stable under elevated temperature conditions that might be experienced during further conversion of the film (z.e. printing or laminating) or during the use of the laminate or packaging film (i.e. heat sealing).
  • the first outer film is biaxially oriented. In some embodiments of the packaging film, the first outer film is monoaxially oriented. In some embodiments of the packaging film, the first outer film is a biaxially oriented polypropylene film. In some embodiments of the packaging film, the second outer film outer film is biaxially oriented. In some embodiments of the packaging film, the second outer film is monoaxially oriented. In some embodiments of the packaging film, the second outer film is a biaxially oriented polypropylene film. In some embodiments of the packaging film, both the first outer film and the second outer film are biaxially oriented polypropylene film.
  • the second outer film may have a second outer film thickness 106T in a range of from 5 microns to 35 microns.
  • the combined thickness of the first outer film and the second outer film (first outer film thickness 104T plus second outer film thickness 106T) may be greater than 50%, 60%, 70% or 80% of the thickness of the packaging film.
  • the first outer film and/or the second outer film may include a surface that is suitable for printing.
  • the surface may include ethylene content (z.e., by way of an ethylene polymer blended into the polypropylene or by way of a propylene ethylene copolymer) and may be corona treated in order to ease the application of printed indicia (i.e., inks).
  • the surface of the film that is printed may be oriented toward the polymer layer or toward the exposed surface of the packaging film.
  • the film upon which an ink is applied should have good dimensional stability under elevated temperatures and tension.
  • the first outer film and/or the second outer film may include a surface that is heat sealable.
  • the surface of the film may contain a C4/C3/C2 terpolymer having a low seal initiation temperature and excellent sealing characteristics.
  • the surface of the film intended for heat sealing is ideally oriented to be exposed at the surface of the packaging film. During heat sealing, the heat sealable surface may be sealed to itself or another surface.
  • the first outer film and/or the second outer film may include a surface that has a cold-seal adhesive applied in a pattern that coordinates with the seals to be formed in a final packaged product.
  • cold-seal adhesive refers to materials that possess the capability of forming a strong bond to themselves when pressure is applied yet are also capable of being applied to a substrate and reeled as a dried film for storage without effecting such a bond. Accordingly, the adhesive must be sufficiently deformable to form a bond under the application of pressure alone, yet sufficiently hard to resist bonding to a substrate during storage. Such adhesives are well known and are used in a variety of applications including as envelope sealants and in food packaging where the application of heat to bond is undesirable.
  • the film to which the cold-seal adhesive is applied may be formulated to adhere well to the adhesive while the film on the opposite side of the packaging film may be formulated to resist adhesion (i.e., by release additives or coatings).
  • the total composition of the packaging film includes very high levels of polypropylene.
  • the packaging film composition may include greater than 30%, 40%, 50% or 60% polypropylene, by weight.
  • the packaging film composition may include less than 90% or 80% polypropylene, by weight.
  • the packaging film composition may include polypropylene in a range of from 30% to 90%, by weight.
  • the packaging film may still be suitable for recycling in a polyolefin recycling stream, due to the composition of the polymer layer as will be described herein.
  • the packaging film may still be suitable for recycling in a polyethylene recycling stream, due to the composition of the polymer layer as will be described herein.
  • the polymer layer is an inner layer and includes a compatibilizer.
  • a compatibilizer is any material that, when added to a multiphase polymer blend, reduces the tendency for the blend’s dispersed phase to coalesce.
  • the average dispersed phase droplet size in a blend that comprises a compatibilizer will be less than the droplet size in a blend that does not comprise a compatibilizer.
  • the theoretical function of the compatibilizer as used in the currently described system is to allow the polypropylene components to blend into the polyethylene matrix more easily during the melting and mixing of the recycling process. During melting and blending of the polymers the polypropylene distributes more evenly, forming smaller sized portions, such that the resulting blend has little to no defects such as gels upon thin film extrusion.
  • the compatibilizer minimizes the effects that the entrained polypropylene has on the physical properties of the polyethylene matrix and resulting thin film.
  • the polymer layer includes at least one compatibilizer selected from the list of a propylene/ethylene copolymer, a 1 -butene rich 1-butene/ethylene plastomer, a polypropylene heterophasic olefin copolymer, an olefin block copolymer, a hydrogenated styrene-butadiene- styrene block copolymer, an ethylene propylene rubber, an ethylene propylene diene monomer and a combination thereof.
  • a compatibilizer selected from the list of a propylene/ethylene copolymer, a 1 -butene rich 1-butene/ethylene plastomer, a polypropylene heterophasic olefin copolymer, an olefin block copolymer, a hydrogenated styrene-butadiene- styrene block copolymer, an ethylene propylene rubber, an ethylene propylene diene monomer
  • the compatibilizer has a composition that includes both propylene and ethylene.
  • the polymer layer includes at least one compatibilizer selected from the list of a propylene/ethylene copolymer (including terpolymers), a polypropylene heterophasic olefin copolymer, an ethylene propylene rubber, an ethylene propylene diene monomer and a combination thereof.
  • the polymer layer includes at least one compatibilizer that is selected from a propylene/ethylene copolymer and a polypropylene heterophasic olefin copolymer.
  • the compatibilizer may be a propylene-rich copolymer (i.e., more than 50% of the linkages are propylene).
  • a propylene/ethylene copolymer may be a propylene/alpha-olefin copolymer.
  • a propylene-rich propylene/ethylene copolymer include elastomers such as Dow VersifyTM 3401 or 3300 and ExxonMobil Vistamaxx 6102 and 6202, and plastomcrs such as Dow VersifyTM 3000.
  • a propylene ethylene copolymer may be a propylene-rich propylene/ethylene/butene terpolymer.
  • Examples of a propylene-rich propylene/ethylene/butene terpolymer include LyondellBassell Adsyl 5 C 30 F and 7416 XCP.
  • Examples of 1 -butene-rich 1-butene/ethylene copolymer include Mitsui TAFMER BL3110 or BL3450.
  • a polypropylene heterophasic olefin copolymer as noted herein preferably has a polypropylene matrix (55 to 90 %, by weight) and an elastomer (10 to 45 %, by weight), such as an ethylene/propylene copolymer or a C4 to CIO alpha-olefin copolymer.
  • An olefin block copolymers may be a polypropylene-based olefin block copolymer such as Dow INTUNETM or may have alternating blocks of rigid and elastomeric segments, such as Dow INFUSETM.
  • An olefin block copolymers may be a triblock or multiblock.
  • SEBS hydrogenated styrene-butadiene-styrene block copolymer
  • An ethylene propylene rubber (EPR) as noted herein preferably has a polyethylene component (50 to 80 %, by weight) and a polypropylene (20% to 50%, by weight), such as a random rubber copolymer of ethylene and propylene.
  • EPR ethylene propylene rubber
  • examples of ethylene propylene rubber (EPR) include Versalis Dutral® CO 034 or CO 038.
  • EPDM ethylene propylene diene monomer
  • the packaging film composition may include greater than 6%, 8%, 10%, 12% or 14% compatibilizer, by weight.
  • the packaging film composition may include less than 40%, 35% or 30% compatibilizer, by weight.
  • the packaging film composition may include compatibilizer in a range of from 10% to 35%, by weight.
  • the polymer layer may also include a stabilizer.
  • the theoretical function of the stabilizer is to offset the negative effects of the incompatibility of the mixed olefin (polyethylene and polypropylene) blend.
  • the stabilizer may “build back” or otherwise improve the physical properties of the blend to result in higher quality films containing the recycled blend.
  • the “stabilizer” is a homogeneously branched linear ethylene polymer or a heterogeneously branched linear ethylene polymer.
  • the stabilizer may be a homogeneously branched linear cthylcnc/alpha olefin copolymer, such as an cthylcnc/hcxcnc copolymer or an ethylene/octene copolymer.
  • Examples of polymers that may be used as a stabilizer include C6-mLLDPE, C6- LLDPE, C8-LLDPE, C8-ULDPE, and C8 plastomer.
  • Examples of homogeneously branched linear ethylene polymers include ENGAGE(TM) grades 8100, 8180 and 8200 (C8 elastomers), available from Dow, Exact(TM) 0210 (C8 plastomer) from ExxonMobil, TAFMER(R) grades from Mitsui, and Queo(R) grades from Borealis.
  • Examples of heterogeneously branched linear ethylene polymers include DOWLEX 3010 available from Dow and ATTANE grades available from Dow.
  • heterogeneous polymer refers to polymerization reaction products of relatively wide variation in molecular weight and relatively wide variation in composition distribution, i.e., typical polymers prepared, for example, using conventional Ziegler-Natta catalysts. Heterogeneous polymers are useful in various layers of the film used in the present invention. Although there are a few exceptions (such as TAFMERTM linear homogeneous ethylene- and alpha-olefin copolymers produced by Mitsui, using Ziegler-Natta catalysts), heterogeneous polymers typically contain a relatively wide variety of chain lengths and co-monomer percentages.
  • homogeneous polymer refers to polymerization reaction products of relatively narrow molecular weight distribution and relatively narrow composition distribution.
  • homogeneous polymers are structurally different from heterogeneous polymers, in that homogeneous polymers exhibit a relatively even sequencing of co-monomers within a chain, a mirroring of sequence distribution in all chains, and a similarity of length of all chains, i.e., a narrower molecular weight distribution.
  • homogeneous polymers arc typically prepared using metallocene, or other single-site type catalysts, rather than using Ziegler Natta catalysts.
  • homogeneous ethylene- and alpha-olefin copolymers may be characterized by one or more methods known to those of skill in the art, such as molecular weight distribution (M W /M n ) composition distribution breadth index (CDBI), and narrow melting point range and single melt point behavior.
  • M W /M n composition distribution breadth index
  • the molecular weight distribution (M W /M n ) also known as polydispersity, may be determined by gel permeation chromatography.
  • the homogeneous ethylene- and alpha-olefin copolymers useful in this invention generally have (M W /M n ) of less than 2.7; preferably from about 1.9 to about 2.5; more preferably, from about 1.9 to about 2.3.
  • composition distribution breadth index (CDBI) of such homogeneous ethylene- and alpha-olefin copolymers will generally be greater than about 70 percent.
  • the CDBI is defined as the weight percent of the copolymer molecules having a co-monomer content within 50 percent (i.e., plus or minus 50 percent) of the median total molar comonomer content.
  • the CDBI of linear polyethylene, which does not contain a co-monomer, is defined to be 100 percent.
  • the Composition Distribution Breadth Index (CDBI) is determined via the technique of Temperature Rising Elution Fractionation (TREF).
  • CDBI determination clearly distinguishes the homogeneous copolymers used in the present invention (narrow composition distribution as assessed by CDBI values generally above 70 percent) from VLDPEs available commercially which generally have a broad composition distribution as assessed by CDBI values generally less than 55 percent.
  • the CDBI of a copolymer is readily calculated from data obtained from techniques known in the art, such as, for example, temperature rising elution fractionation as described, for example, in Wild et. al., J. Poly. Sci. Poly. Phys. Ed., Vol. 20, p.441 (1982).
  • the homogeneous ethylene- and alpha-olefin co-polymers have a CDBI greater than about 70 percent, i.e., a CDBI of from about 70 percent to about 99 percent.
  • the homogeneous ethylene- and alpha-olefin co-polymers in the multi-layer films of the present invention also exhibit a relatively narrow melting point range, in comparison with “heterogeneous copolymers”, i.e., polymers having a CDBI of less than 55 percent.
  • the homogeneous ethylene- and alpha-olefin copolymers exhibit an essentially singular melting point characteristic, with a peak melting point (T m ), as determined by Differential Scanning Calorimetry (DSC), of from about 60 degrees centigrade to about 110 degrees centigrade
  • the homogeneous copolymer has a DSC peak T m of from about 80 degrees centigrade to about 105 degrees centigrade
  • the phrase “essentially single melting point” means that at least about 80 percent, by weight, of the material corresponds to a single T m peak at a temperature within the range of from about 60 degrees centigrade to about 110 degrees centigrade, and essentially no substantial fraction of the material has a peak melting point in excess of about 115 degrees centigrade, as determined by DSC analysis.
  • Melting information reported are second melting data, i.e., the sample is heated at a programmed rate of 10 degrees centigrade /min. to a temperature below its critical range. The sample is then reheated (2nd melting) at a programmed rate of 10 degrees centigrade /min.
  • 2nd melting a programmed rate of 10 degrees centigrade /min.
  • the presence of higher melting peaks is detrimental to film properties such as haze, and compromises the chances for meaningful reduction in the seal initiation temperature of the final film.
  • a homogeneous ethylene- and alpha-olefin copolymer can, in general, be prepared by the co-polymerization of ethylene and any one or more and alpha-olefins.
  • the alphaolefin is a C 4 -C 2 and alpha-mono-olefin, still more preferably, a C 4 -C 8 and alpha-mono- olefin.
  • the alpha-olefin comprises at least one member selected from the group consisting of butene- 1, hexene- 1, and octene- 1, i.e., 1 -butene, 1 -hexene, and 1 -octene, respectively.
  • the alpha-olefin comprises octene-1, and/or a blend of hexene- 1 and butene- 1.
  • ethylene- and alpha-olefin copolymer refer to such heterogeneous materials as linear low density polyethylene (LLDPE), linear medium density polyethylene (LMDPE) and very low and ultra low density polyethylene (VLDPE and ULDPE); and homogeneous polymers such as metallocene-catalyzed EXACTTM linear homogeneous ethylene- and alpha-olefin copolymer resins obtainable from Exxon, single- site AFFFNITYTM linear homogeneous ethylene- and alpha-olefin copolymer resins obtainable from Dow, and TAFMERTM linear homogeneous ethylene- and alpha-olefin copolymer resins obtainable from Mitsui.
  • All these materials generally include co-polymers of ethylene with one or more co-monomers selected from C4 to C10 and alpha-olefin such as butene- 1, hexene- 1, octene- 1, etc. in which the molecules of the copolymers comprise long chains with relatively few side chain branches or cross-linked structures.
  • the heterogeneous ethylene- and alphaolefin co-polymer commonly known as LLDPE has a density usually in the range of from about 0.915 g/cm 3 to about 0.930 g/cm 3
  • that commonly known as LMDPE has a density usually in the range of from about 0.930 g/cm 3 to about 0.945 g/cm 3
  • those commonly identified as VLDPE or ULDPE have a density lower than about 0.915 g/cm 3 .
  • the polymer layer may be a single layer having a homogeneous composition including the compatibilizer and optionally, the stabilizer. In this case the polymer layer would have one major surface coupled to the first outer film and the other major surface coupled to the second outer film.
  • the polymer layer may include two or more sub-layers and the compatibilizer and the stabilizer (if present) may be present in any one or more sub-layer.
  • the polymer layer may have 2, 3, 4, 5, 6, 7, 8, 9 or 10 sub-layers.
  • the polymer layer may contain an odd number of sub-layers and the composition and thickness of those sub-layers may form a palindromic sequence, such as ABA, ABCBA, or ABCDCBA where each letter represents a layer of the same composition and thickness.
  • Polymer layer 208 includes a first sub-layer 210, a second sub-layer 212 and a third sub-layer 214.
  • Second sub-layer 212 is located between and directly adjacent to first sub-layer 210 and third sub-layer 214. In other embodiments of the polymer layer, there may be intervening layers between the second sub-layer 212 and either or both of first sub-layer 210 and third sub-layer 214.
  • the first sub-layer of the polymer layer may be coupled to the first outer film and may include a composition to enhance adhesion thereto.
  • the first sub-layer may include low-density polyethylene (LDPE) or non-neutralized ethylene acid copolymer or other adhesion enhancing polymers such as ethylene methyl acrylate copolymer (EMA).
  • LDPE low-density polyethylene
  • EMA ethylene methyl acrylate copolymer
  • the third sublayer of the polymer layer may be coupled to the first outer film and may include a composition to enhance adhesion thereto.
  • the third sub-layer may include low-density polyethylene (LDPE) or non-neutralized ethylene acid copolymer or other adhesion enhancing polymers such as ethylene methyl acrylate copolymer (EMA).
  • low density polyethylene or “LDPE” is used to denominate branched homopolymers having densities between 0.915 and 0.930 grams per cubic centimeter. LDPEs typically contain long branches off the main chain (often termed “backbone") with alkyl substituents of 2 to 8 carbon atoms.
  • non-neutralized ethylene acid copolymer may include ethylenically unsaturated carboxylic acids and ethylenically unsaturated anhydrides. Ethylenically unsaturated carboxylic acids may be categorized as monobasic or dibasic.
  • Non-limiting examples of monobasic ethylenically unsaturated carboxylic acids include ethylene acrylic acid (EAA), ethylene methacrylic acid (EMAA), ethylene crotonic acid, and may also include corresponding partial esters.
  • Non-limiting examples of dibasic ethylenically unsaturated carboxylic acids include fumaric acid, maleic acid, itaconic acid, and may also include corresponding partial esters.
  • Non-limiting examples of ethylenically unsaturated anhydrides include maleic anhydride, phthalic anhydride, hydrolyzed maleic anhydride, hydrolyzed phthalic anhydride, and may also include corresponding partial esters.
  • ethylene acid copolymers may include terpolymers formed from the aforementioned ethylenically unsaturated carboxylic acids or anhydrides and ethylene or the following comonomers 1) vinyl acetate, 2) acrylates (methyl, ethyl, n-butyl, ethyl hexyl, etc.), 3) methacrylates, 4) glycidyl methacrylate, or 5) carbon monoxide.
  • the non-neutralized ethylene acid copolymer may include any of the aforementioned copolymers or blends thereof that do not include partially neutralized ethylene acid copolymers.
  • the packaging film may be assembled by any known series of converting operations including but not limited to blown film extrusion, cast film extrusion, orientation, metallization, printing, lamination, extrusion lamination, and slitting.
  • the polymer layer may be an extrusion laminated between the first outer film and the second outer film.
  • FIG. 3 shows an embodiment of the packaging film 302 including a first outer film 304, a second outer film 306, polymer layer 308, an ink 316 located on the surface of the first outer film 304 and a metallization layer 318 located on the surface of the second outer film 306.
  • “ink” is referring to printed indicia applied to the surface of a film (z.e. , the first outer film) by a common converting process such as flexographic or rotogravure printing, although the process by which it is applied is not limited.
  • Ink 316 has a polymeric base and pigments for color.
  • the ink is typically pattern applied in various colors in order to produce graphics and/or information on the packaging film.
  • the ink 316 is reverse printed on the inner surface of the first outer film 304 and can be viewed through the first outer film 304.
  • the ink may be applied on the outer surface of the first outer film, at the exterior surface of the packaging film.
  • the ink may be applied on the inner surface of the second outer film.
  • the term "metallization layer”, “metallized” or “metal coating” refers to a coating that may be applied to one or both surfaces of a film by any known method such as sputtering, vacuum deposition or electroplating (all of which fall within the definition of "metallizing” the film and involve some act or method of "depositing” a continuous metal, metal oxide or metal alloy layer onto the surface of a polymer substrate).
  • the metal used can vary, though aluminum, zinc, gold, silver or appropriate alloys of such are preferred, with aluminum or aluminum-containing alloys being particularly preferred.
  • the metal coating predominantly consists of the identified metal (such as aluminum)
  • amounts of other additives may be present to improve assorted physical and optical properties of the deposited metal layer.
  • pure aluminum or the metal of choice
  • Other additives maybe used in minor amounts such that aluminum (or the metal of choice) is the major component.
  • Vacuum deposition is a preferred method of metallization in trends of processing and cost.
  • Preferred values for the average thickness of the metal coating layer are within the range of about 1.0 to 100 nanometers, with the preferred average thickness being within the range of about 3 to 25 nanometers. (1 micron equals 10. sup. -7 meters, and 1 nanometer equals 10. sup.
  • the metal coating preferably has a thickness less than the polymer substrate on which it is deposited, preferably substantially less than said substrate.
  • the packaging films may include other barrier materials such as, but not limited to SiOx, AlOx, EVOH, and PVOH. These materials may be included at a level that the recyclability of the packaging film is not diminished.
  • the packaging film may have a packaging film thickness 102T (see Figure 1) greater than 15, 20 or 25 micron.
  • the packaging film may have a packaging film thickness 102T less than 150, 125, 100 or 90 micron.
  • the packaging film may have a packaging film thickness 102T in a range of from 15 micron to 100 micron.
  • the packaging film may be used to form a packaged product.
  • packaged product refers to the one or more packaging components (i.e., the packaging film, two packaging films, a tray, a zipper, etc.) forming a hermetically sealed package and the product therein.
  • hermetically sealed refers to a seal or sealed package that is completely closed and essentially airtight.
  • Hermetically sealed packages generally have a need for storage and package integrity over a period that is greater than a few days.
  • Package integrity includes a consistent appearance, maintenance of barrier properties, maintenance of lamination bonds, and maintenance of seals.
  • the term "package” refers to an article formed of packaging components, such as packaging film, having a cavity capable of holding a product.
  • the package may be hermetically sealed and may provide protection for the product during storage and distribution.
  • the inside surface of the packaging film z.e., the second outer film or the interior layer
  • the outside surface z.e., the first outer film or the exterior layer
  • the package may take any form and the packaging film may form the entire package or may be combined with other packaging components to form the package.
  • Packaged product 420 is a package formed entirely of packaging film 402, containing a product (not shown), the package in the form of a pillow pack.
  • the packaging film 402 is wrapped around the product in roughly a tube configuration with the longitudinal edges sealed to each other in a seam 424 running the length of the package.
  • the seam 424 may be a fin seal or a lap seal.
  • fin seal refers to a seam that includes bonding the interior surface of the packaging film to itself. A fin seal generally protrudes from the package, although it may be folded over to be flat against the exterior of the package.
  • lap seal refers to a seam that includes bonding the interior surface (z'.e., the interior layer, the second outer film) of one edge of the packaging film to the exterior surface (i.e., the exterior layer, the first outer oriented film) of another edge of the packaging film.
  • the edges of the packaging film overlap and are bonded together.
  • End seals 422 close each end of the tube, creating the cavity in which the product is held.
  • end seals refers to a seal bonding the inside surface of the packaging film to itself, located at the end of a package, traversing from one side to the other side of the package.
  • the end seals are placed in a transverse direction (i.e., perpendicular to machine direction) between packages, and the single packages are usually cut apart at or near the end seals such that a finished package has an end seal at each end.
  • the end seals 422 may be formed by heat seals that bond the interior surface (i.e., the interior layer, the second outer film) to itself.
  • the product enclosed within the package made of the packaging film is not limited.
  • the product may be of the type that benefits from protection from moisture, oxygen or light, as may be provided by the packaging film.
  • Examples of products include food, such as chips, crackers, snacks, grains, dry powders, confectionary, candy or nut butters.
  • Examples of products include cosmetic items such as loose powder, facial wipes or lotions.
  • Examples of products include home/industrial products such as cleaning wipes, powdered cleaner or pet food.
  • the first outer film is a transparent biaxially oriented polypropylene film having a thickness of about 18 micron.
  • the first outer film is printed resulting in an ink located on a surface of the first outer film.
  • the second outer film is a white opaque biaxially oriented polypropylene film that is heat sealable and has a thickness of about 18 micron.
  • the second outer film is metallized.
  • the first outer film and second outer film are coupled by formation of a polymer layer by coextrusion lamination resulting in a structure of: first outer film I ink I first sub-layer / second sub-layer / third sublayer / metallization layer / second outer film.
  • the first sub-layer and the third sub-layer each include a non-neutralized ethylene acid copolymer and the second sub-layer includes a compatibilizer and a stabilizer.
  • the first outer film is a transparent biaxially oriented polypropylene film having a thickness of about 18 micron.
  • the first outer film is printed resulting in an ink located on a surface of the first outer film.
  • the second outer film is a transparent biaxially oriented polypropylene film that is heat sealable and has a thickness of about 18 micron.
  • the second outer film is metallized.
  • the first outer film and second outer film are coupled by formation of a polymer layer by coextrusion lamination resulting in a structure of: first outer film I ink I first sub-layer I second sub-layer I third sublayer / metallization layer I second outer film.
  • the first sub-layer and the third sub-layer each include a non-neutralized ethylene acid copolymer and the second sub-layer includes a compatibilizer and a white pigment.
  • the first outer film is a transparent biaxially oriented polypropylene film having a thickness of about 18 micron.
  • the first outer film is printed resulting in an ink located on a surface of the first outer film.
  • the second outer film is a white opaque biaxially oriented polypropylene film that is heat scalable and has a thickness of about 18 micron.
  • the first outer film and second outer film are coupled by formation of a polymer layer by coextrusion lamination resulting in a structure of: first outer film / ink / first sub-layer / second sub-layer / third sub-layer / metallization layer / second outer film.
  • the first sub-layer and the third sub-layer each include a non-neutralized ethylene acid copolymer and the second sub-layer includes a compatibilizer and a stabilizer.
  • the first outer film is a transparent biaxially oriented polypropylene film having a matte appearance and a thickness of about 18 micron.
  • the first outer film is printed resulting in an ink located on a surface of the first outer film.
  • the second outer film is a white opaque biaxially oriented polypropylene film that is heat sealable and has a thickness of about 27.5 micron.
  • the first outer film and second outer film are coupled by formation of a polymer layer having a basis weight of approximately 5 Ib/ream, by coextrusion lamination resulting in a structure of: first outer film / ink / first sub-layer / second sub-layer / third sub-layer / metallization layer / second outer film.
  • the first sub-layer and the third sub-layer each include a polyethylene and the second sub-layer includes a compatibilizer.
  • the first prophetic example of a packaging film is formed into a pillow pack and filled with potato chips, using vertical form fill seal machine.
  • the package has a lap seal style seal running the length of the package and an end seal at each end.
  • the package upon opening and emptying (i.e., by a consumer), can be recycled in an in-store drop off stream intended for polyethylene bags and similar items.
  • Two films, Comparative film 1 and Example film 2 were simulated to test the effects of the inclusion of a compatibilizer in the polymer layer of a packaging film.
  • the simulation of the films was done by producing each of the components of the film separately and then processing the combination of those films for the recycling test described below.
  • the simulated films had a target structure of polyethylene extrusion lamination of two standard 18 micron BOPP films.
  • the standard BOPP films had a core layer of homopolymer polypropylene (80% by volume of the BOPP) and a skin layer on each side of the core of copolymer polypropylene (10% by volume in each skin).
  • the polyethylene extrusion lamination layer was simulated by an extruded film having a thickness of 10 pounds per ream (Ib/rm) and including three sublayers.
  • the two outer sub-layers comprised 100% LDPE for Comparative film 1 and Example film 2.
  • the films differed by the center sub-layer of the polymer layer (z.e., the simulated polyethylene extrusion lamination layer).
  • Comparative film 1 had a center sub-layer of LLDPE and LDPE and Example film 2 had a center sub-layer of a blend of LLDPE, LDPE and 50% polypropylene/polyethylene elastomer, Vistamaxx 6202FL.
  • Comparative film 1 and Example film 2 each contained 66% polypropylene by weight.
  • each of the BOPP films and the extrusion lamination simulating film were produced and separately shredded, then combined in the correct proportion, melted, mixed and pelletized.
  • the pellets from the films were then blended at a 50:50 ratio with pellets similarly obtained from a control polyethylene film (65 wt% MDPE, 20 wt% HDPE, 15 wt% LDPE). These blended pellets were then made into a 2 mil thick film in a blown film process.
  • Test film 3 was made using Comparative film 1 and Test film 4 was made using Example film 2.
  • An additional Test film 5 was produced by using 100% of the control polyethylene film through the melt-mixing, pelletizing and film production.
  • Test film 3 and Test film 4 were then tested to compare physical properties of the films. The results of these tests are shown in Table 1.
  • Impact strength is Dart Drop measured using ASTM D7192 implementing a 0.75 in radius probe, 10.63 +/- 0.02 ft/sec velocity and 10.55 pound weight.
  • MD and TD tear data is Elmendorf Tear measured according to ASTM DI 922 using a 200 g pendulum for the MD measurements and a 1 ,600 g pendulum for the TD measurements. TABLE 1: Recyclability Analysis on the Addition of Compatibilizer
  • Test film 5 By comparing the data of Test film 5 to Test film 3, it is evident that the addition of the standard BOPP films to the packaging film is detrimental, lowering impact strength, MD tear and TD tear significantly.
  • the addition of the compatibilizer to the packaging film shows a further slight reduction in impact strength, but clear improvement in the MD tear and TD tear.
  • the reduced reduction of tear properties of Test film 4 indicate an easier to recycle film (Example film 2).
  • the films were simulated as described in the previous example films.
  • the simulated films were to be an extrusion lamination of a standard BOPP film, as described above, to a monoaxially oriented polypropylene film (MDOPP).
  • the MDOPP of Comparative film 6 and Example film 7 had a core layer of standard polyethylene (no compatibilizer or stabilizer) and a skin layer on each side of the core of homopolymer polypropylene.
  • the MDOPP of Example film 8 had stabilizer in the core.
  • the oriented films were bonded by a polymer layer applied at a thickness of 10 pounds per ream (Ib/rm) comprised of polyethylene.
  • Comparative film 6 contained no compatibilizer or stabilizer
  • Example film 7 contained 50% Vistamaxx 6202FL compatibilizer and no stabilizer
  • Example film 8 contained 50% Vistamaxx 6202FL compatibilizer in the polymer layer and 25% FP120 C8 LLDPE stabilizer in the MDOPP film.
  • Example film 7 and Example film 8 had a polypropylene content of 33% by weight.
  • the films were processed through a process of shredding the films, melt-mixing and pelletizing them, and finally dry mixing the pellets at a 50:50 ratio with a similarly pelletized control polyethylene film (65 wt% MDPE, 20 wt% HDPE, 15 wt% LDPE). These pellets were blended and extruded into a 2 mil thick film in a blown film process.
  • Test film 9 was made using Comparative film 6
  • Test film 10 was made using Example film 7
  • Test film 11 was made using Example film 8.
  • Test film 5 was produced by using 100% of the control polyethylene film through the melt-mixing, pelletizing and film production.
  • Test films 5, 9, 10 and 11 were then tested to compare physical properties of the films. The results of these tests are shown in Table 2.
  • Impact strength is Dart Drop measured using ASTM D7192 implementing a 0.75 in radius probe, 10.63 +/- 0.02 ft/sec velocity and 10.55 pound weight.
  • MD and TD tear data is Elmendorf Tear measured according to ASTM DI 922 using a 200 g pendulum for the MD measurements and a 1 ,600 g pendulum for the TD measurements.
  • Test film 9 By comparing the data of Test film 9 to Test film 3, it is evident that the addition of the polypropylene to the packaging film is detrimental, lowering impact strength, MD tear and TD tear.
  • the addition of the compatibilizer to the packaging film shows a further slight reduction in impact strength, but clear improvement in the MD tear and TD tear.
  • Further addition of a stabilizer to the packaging film shows that a portion of the impact strength can be regained.
  • the reduced reduction of impact strength and tear properties of Test films 10 and 11 indicate an easier to recycle film (Example films 7 and 8, respectively).
  • references in the specification to “one embodiment” or “one aspect” indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment.
  • the term “and/or” refers to any one of the items, any combination of the items, or all of the items with which this term is associated.
  • the singular forms “a,” “an,” and “the” include plural reference unless the context clearly dictates otherwise.
  • the terms “include,” “for example,” “such as,” and the like are used illustratively and are not intended to limit the present invention.
  • the terms “preferred” and “preferably” refer to embodiments of the invention that may afford certain benefits, under certain circumstances. However, other embodiments may also be preferred, under the same or other circumstances.
  • the recitation of one or more preferred embodiments does not imply that other embodiments are not useful and is not intended to exclude other embodiments from the scope of the invention.
  • Embodiment 1 A packaging film comprising: a first outer film comprising polypropylene; a second outer film comprising polypropylene; and a polymer layer connecting the first outer film and the second outer film; wherein the polymer layer comprises a compatibilizer selected from a group consisting essentially of a propylene/ethylene copolymer, a 1 -butene rich 1-butene/ethylene plastomer, a polypropylene heterophasic olefin copolymer, an olefin block copolymer, a hydrogenated styrene-butadiene-styrene block copolymer, an ethylene propylene rubber, an ethylene propylene diene monomer and a combination thereof.
  • a compatibilizer selected from a group consisting essentially of a propylene/ethylene copolymer, a 1 -butene rich 1-butene/ethylene plastomer, a polypropylene heterophasic olefin copo
  • Embodiment 2 The packaging film of embodiment 1, wherein the polymer layer further comprises a stabilizer selected from a group consisting essentially of a homogeneously branched linear ethylene polymer, a heterogeneously branched linear ethylene polymer and a combination thereof.
  • a stabilizer selected from a group consisting essentially of a homogeneously branched linear ethylene polymer, a heterogeneously branched linear ethylene polymer and a combination thereof.
  • Embodiment 3 The packaging film of embodiment 1 or 2, wherein each of the first outer film and the second outer film are independently biaxially oriented or monoaxially oriented.
  • Embodiment 4 The packaging film of any one of embodiments 1 to 3, wherein the first outer film comprises a first outer film composition comprising polypropylene in a range of from 80% to 100%, by weight, and a thickness in a range of from 5 microns to 35 microns.
  • Embodiment 5 The packaging film of embodiment 4, wherein the second outer film comprises a second outer film composition comprising polypropylene in a range of from 80% to 100%, by weight, and a thickness in a range of from 5 microns to 35 microns.
  • Embodiment 6 The packaging film of any one of embodiments 1 to 5, wherein the packaging film comprises a packaging film composition comprising polypropylene in a range of from 30% to 90%, by weight.
  • Embodiment 7 The packaging film of any one of embodiments 1 to 6, wherein the polymer layer comprises a first sub-layer, a second sub-layer, and a third sub-layer, and the second sub-layer is located between the first sub-layer and the third sub-layer.
  • Embodiment 8 The packaging film of embodiment 7, wherein the first sub-layer is adjacent to the first outer film, the third sub-layer is adjacent to the second outer film, and at least one of the first sub-layer and the third sub-layer comprise at least one of low-density polyethylene and non-neutralized ethylene acid copolymer.
  • Embodiment 9 The packaging film of embodiment 7 or 8, wherein the second sublayer comprises the compatibilizer.
  • Embodiment 10 The packaging film of any one of embodiments 1 to 9, wherein the packaging film has a packaging film composition comprising the compatibilizer in a range of from 10% to 35%, by weight.
  • Embodiment 11 The packaging film of any one of embodiments 1 to 10, wherein the compatibilizer is a propylene-rich propylene/ethylene copolymer.
  • Embodiment 12 The packaging film of any one of embodiments 1 to 11, wherein the compatibilizer is a propylene/alpha-olefin copolymer.
  • Embodiment 13 The packaging film of embodiment 2, wherein the stabilizer is a homogeneously branched linear ethylene polymer.
  • Embodiment 14 The packaging film of embodiment 13, wherein the stabilizer is an ethylene/hexene copolymer or an ethylene/octene copolymer.
  • Embodiment 15 A packaging film adapted for recycling in a polyolefin recycling stream, the packaging film comprising: a first outer film comprising at least 80% polypropylene, by weight; a second outer film comprising at least 80% polypropylene, by weight; and a polymer layer connecting the first outer film and the second outer film; wherein the polymer layer comprises a compatibilizer selected from a group consisting essentially of a propylene/ethylene copolymer, a 1 -butene rich 1 -butene/ethylene plastomer, a polypropylene hctcrophasic olefin copolymer, an olefin block copolymer, a hydrogenated styrcnc-butadicnc- styrene block copolymer, an ethylene propylene rubber, ethylene propylene diene monomer rubber, and a combination thereof; wherein the polymer layer comprises a stabilizer selected from the group consisting
  • Embodiment 16 The packaging film of any one of embodiments 1 to 15, further comprising a metallization layer located on a surface of the second outer film.
  • Embodiment 17 The packaging film of any one of embodiments 1 to 16, further comprising ink located between the first outer film and the polymer layer.
  • Embodiment 18 The packaging film of any one of embodiments 1 to 17, further comprising a thickness in a range of from 15 micron to 100 micron.
  • Embodiment 19 The packaging film of any one of embodiments 15 to 18, wherein the packaging film composition comprises in a range of from 30% to 80%, by weight, of the first outer film and the second outer film.
  • Embodiment 20 A packaging film adapted for recycling in a polyolefin recycling stream, the packaging film comprising: a first outer film comprising a biaxially oriented polypropylene film; a second outer film comprising a biaxially oriented polypropylene film; a polymer layer connecting the first outer film and the second outer film; and a metallization layer located on a surface of the second outer film, the metallization layer located between the second outer film and the polymer layer; wherein the polymer layer comprises at least one of a compatibilizer and a stabilizer; and wherein the compatibilizer is selected from a group consisting essentially of a propylene/ethylene copolymer, a 1 -butene rich 1-butene/ethylene plastomer, a polypropylene heterophasic olefin copolymer, an olefin block copolymer, a hydrogenated styrene-butadiene- styrene block copolymer,
  • Embodiment 21 The packaging film of any one of embodiments 1 to 20 wherein the packaging film comprises a barrier layer.
  • Embodiment 22 The packaging film of any one of embodiments 1 to 21, wherein the compatibilizer is selected from a group consisting essentially of a propylene/ethylene copolymer, a polypropylene heterophasic olefin copolymer, an ethylene propylene rubber, an ethylene propylene diene monomer and a combination thereof.
  • the compatibilizer is selected from a group consisting essentially of a propylene/ethylene copolymer, a polypropylene heterophasic olefin copolymer, an ethylene propylene rubber, an ethylene propylene diene monomer and a combination thereof.
  • Embodiment 23 A packaged product comprising: a packaging film of any one of embodiments 1 to 22, and a product; wherein the packaging film is sealed to form a package and the product is enclosed within the package.
  • Embodiment 24 A packaged product comprising: a packaging film sealed to form a package and a product enclosed within the package, the packaging film comprising: a first outer film comprising polypropylene; a second outer film comprising polypropylene; and a polymer layer connecting the first outer film and the second outer film; wherein the polymer layer comprises a compatibilizer selected from a group consisting essentially of a propylene/ethylene copolymer, a 1 -butene rich 1-butene/ethylene plastomer, a polypropylene heterophasic olefin copolymer, an olefin block copolymer, a hydrogenated styrene-butadiene- styrene block copolymer, an ethylene propy
  • a compatibilizer selected
  • Embodiment 25 The packaged product of embodiment 23 or 24, wherein the package is in the form of a pillow pack comprising two end seals and a seam, the seam formed as a fin seal or as a lap seal.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Laminated Bodies (AREA)
  • Wrappers (AREA)

Abstract

La présente invention concerne un film d'emballage comprenant un premier film externe et un second film externe, tous deux constitués de polypropylène, et une couche polymère qui relie les premier et second films externes. La couche de polymère comprend un agent de compatibilité choisi dans un groupe constitué essentiellement d'un copolymère de propylène/éthylène, d'un plastomère de 1-butène/éthylène riche en 1-butène, d'un copolymère d'oléfine hétérophasique de polypropylène, d'un copolymère séquencé d'oléfine, d'un copolymère séquencé de styrène-butadiène-styrène hydrogéné, d'un caoutchouc d'éthylène-propylène, d'un monomère d'éthylène-propylène-diène et d'une combinaison de ceux-ci. Le film d'emballage assure une compatibilité améliorée entre les couches de polypropylène, ce qui permet d'obtenir une aptitude au recyclage améliorée et des propriétés mécaniques améliorées.
PCT/US2025/018222 2024-03-04 2025-03-03 Film d'emballage multicouche à couche polymère compatibilisée Pending WO2025188673A1 (fr)

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5885703A (en) * 1996-08-19 1999-03-23 Aep Industries, Inc. Biaxially oriented polypropylene aroma barrier film
US20050282025A1 (en) * 2004-06-21 2005-12-22 Brown Michael J Article comprising polyester multilayer film
US20160185085A1 (en) * 2013-05-16 2016-06-30 Cryovac, Inc. Blend and film exhibiting resistance to ink abrasion
US20210347148A1 (en) * 2018-08-31 2021-11-11 Dai Nippon Printing Co., Ltd. Heat-sealable laminate, laminated substrate, laminate for gas barrier intermediate layer, laminate for packaging material, and packaging material
US20230364891A1 (en) * 2020-10-30 2023-11-16 Amcor Flexibles North America, Inc. Oriented film containing recycled polyamide
US20240010404A1 (en) * 2020-09-11 2024-01-11 Toyo Seikan Group Holdings, Ltd. Layered body for packaging

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5885703A (en) * 1996-08-19 1999-03-23 Aep Industries, Inc. Biaxially oriented polypropylene aroma barrier film
US20050282025A1 (en) * 2004-06-21 2005-12-22 Brown Michael J Article comprising polyester multilayer film
US20160185085A1 (en) * 2013-05-16 2016-06-30 Cryovac, Inc. Blend and film exhibiting resistance to ink abrasion
US20210347148A1 (en) * 2018-08-31 2021-11-11 Dai Nippon Printing Co., Ltd. Heat-sealable laminate, laminated substrate, laminate for gas barrier intermediate layer, laminate for packaging material, and packaging material
US20240010404A1 (en) * 2020-09-11 2024-01-11 Toyo Seikan Group Holdings, Ltd. Layered body for packaging
US20230364891A1 (en) * 2020-10-30 2023-11-16 Amcor Flexibles North America, Inc. Oriented film containing recycled polyamide

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