Multilayer packaging film with polypropylene and polyethylene

Abstract

A packaging film is disclosed that includes an oriented polypropylene film coupled to a polyethylene film. The polyethylene film includes a compatibilizer selected from the group including a propylene / ethylene copolymer, a 1-butene / ethylene plastomer rich in 1-butene, a polypropylene heterophasic olefin copolymer, an olefin block copolymer, a hydrogenated styrene-butadiene-styrene block copolymer, an ethylene propylene rubber, a terpolymer ethylene propylene rubber, or a combination thereof; or a stabilizer selected from the group including a homogeneously branched linear ethylene polymer, a heterogeneously branched linear ethylene polymer, or a combination thereof; or both.

Description

Technical Field

[0001] This application relates to packaging films and packaging products made therefrom. The packaging films contain structures and compositions designed for easy recycling. Background Technology

[0002] Previous approaches to packaging films involved combining various types of materials to achieve desired properties such as strength, flexibility, and barrier properties. For example, polypropylene (PP) films are commonly used in packaging applications due to their excellent mechanical properties and heat resistance. However, PP films alone may lack certain properties crucial for packaging applications, such as sealability and impact resistance. To address these limitations, polyethylene (PE) films have been incorporated into packaging structures to enhance sealability and impact resistance. In packaging applications, combinations of PP and PE films have been explored to leverage the individual advantages of each material. Summary of the Invention

[0003] In one aspect, a packaging film includes an oriented polypropylene film coupled to a polyethylene film, wherein the polyethylene film comprises at least one of a) a compatibilizer and b) a stabilizer, the compatibilizer being selected from the group consisting substantially of: propylene / ethylene copolymers, 1-butene-rich 1-butene / ethylene plastomers, polypropylene multiphase olefin copolymers, olefin block copolymers, hydrogenated styrene-butadiene-styrene block copolymers, ethylene propylene rubber, EPDM rubber, and combinations thereof, and the stabilizer being selected from the group consisting substantially of: homogeneous branched linear ethylene polymers, heterogeneous branched linear ethylene polymers, and combinations thereof. A packaged product includes a packaging film and a product, wherein the packaging film is sealed to form a package, and the product is encapsulated within the package.

[0004] In another aspect, a packaging film suitable for recycling in a polyolefin recycling stream comprises: an oriented film comprising 80% to 100% polypropylene by weight; a multilayer film comprising 50% to 100% polyethylene by weight; and an adhesive layer linking the oriented film to the multilayer film, wherein the multilayer film comprises at least one of a compatibilizer and a stabilizer, wherein the compatibilizer is selected from the group consisting substantially of: propylene / ethylene copolymers, 1-butene-rich 1-butene / ethylene plastomers, polypropylene multiphase olefin copolymers, olefin block copolymers, hydrogenated styrene-butadiene-styrene block copolymers, ethylene propylene rubber, EPDM rubber, and combinations thereof. Suitable packaging films also comprise stabilizers selected from the group consisting substantially of: homogeneous branched linear ethylene polymers, heterogeneous branched linear ethylene polymers, and combinations thereof.

[0005] In another aspect, a packaging film suitable for recycling in a polyolefin recycling stream comprises a biaxially oriented polypropylene film coupled to a multilayer polyethylene film; wherein the multilayer polyethylene film comprises at least one of a compatibilizer and a stabilizer, and wherein the compatibilizer is selected from the group consisting substantially of: propylene / ethylene copolymers, 1-butene-rich 1-butene / ethylene plastomers, polypropylene multiphase olefin copolymers, olefin block copolymers, hydrogenated styrene-butadiene-styrene block copolymers, ethylene propylene rubber, EPDM rubber, and combinations thereof, wherein the stabilizer is selected from the group consisting substantially of: homogeneous branched linear ethylene polymers, heterogeneous branched linear ethylene polymers, and combinations thereof, wherein the packaging film comprises at least one of a compatibilizer and a stabilizer in the range of 10% to 35% by weight.

[0006] Other technical features will be obvious to those skilled in the art based on the following drawings, description and claims. Attached Figure Description

[0007] This disclosure can be more fully understood by considering the following detailed description of various embodiments of the disclosure in conjunction with the accompanying drawings, wherein: Figure 1 A cross-sectional view of an embodiment of a packaging film including an oriented polypropylene film coupled to a polyethylene film.

[0008] Figure 2 A cross-sectional view of an embodiment of a packaging film including an oriented film connected to a multilayer film via an adhesive layer.

[0009] Figure 3 A cross-sectional view of an embodiment of a packaging film including a biaxially oriented polypropylene film coupled to a multilayer polyethylene film.

[0010] Figure 4 A perspective view of an embodiment of a packaged product including a packaging film.

[0011] The accompanying drawings illustrate some, but not all, of the embodiments. The elements depicted in the drawings are illustrative and not necessarily drawn to scale, and throughout the drawings, the same (or similar) reference numerals denote the same (or similar) features. Detailed Implementation

[0012] The following detailed description includes reference to the accompanying drawings, which form part of the detailed description. The drawings schematically illustrate specific embodiments in which the invention can be practiced. These embodiments, also referred to herein as “examples,” are described in sufficient detail to enable those skilled in the art to practice the invention. Combinations of embodiments may be made, other embodiments may be adopted, or structural and logical changes may be made without departing from the scope of the invention. Therefore, the following detailed description should not be construed as limiting. However, before such detailed description of the invention, it should be understood that the invention is not limited to the specific variations set forth, and changes are certainly possible.

[0013] Various changes may be made to the described invention without departing from its true spirit and scope, and equivalents may be substituted. Furthermore, numerous modifications may be made to adapt particular circumstances, materials, composition, processes, process actions, or steps to the objectives, spirit, or scope of the invention. All such modifications are intended to fall within the scope of this disclosure.

[0014] Unless otherwise stated, the words and phrases appearing in this document have their ordinary meanings as understood by those skilled in the art. Such ordinary meanings can be obtained by referring to their usage in the art and by consulting general and scientific dictionaries.

[0015] The use of "one embodiment" in the specification indicates that the described embodiment may include a specific feature, structure, or characteristic, but not every embodiment necessarily includes that specific feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment.

[0016] Furthermore, when describing a particular feature, structure, or characteristic in conjunction with an implementation scheme, it should be assumed that the influence of such feature, structure, or characteristic on other implementation schemes is within the knowledge of a person skilled in the art, whether or not it is explicitly described.

[0017] The following explanations of certain terms are intended to be illustrative rather than exhaustive. These terms have their common meaning as given by their usage in this field, and the following explanations are also included.

[0018] As used herein, the term “and / or” means any one item, any combination of items, or all items associated with the term.

[0019] As used herein, unless the context clearly indicates otherwise, the singular forms “a”, “an”, and “the” include plural references.

[0020] As used herein, the terms “comprising,” “for example,” “such as,” etc., are used illustratively and are not intended to limit the invention.

[0021] As used herein, the terms "preferred" and "ideally" refer to embodiments of the invention that provide certain benefits in certain circumstances. However, other embodiments may also be preferred in the same or other circumstances.

[0022] Furthermore, the description of one or more preferred embodiments does not imply that other embodiments are unavailable, and is not intended to exclude other embodiments from the scope of the invention.

[0023] It should be understood that although the terms first, second, etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used only to distinguish one element from another. For example, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element, without departing from the teachings of this disclosure.

[0024] This disclosure includes a packaging film design comprising a polyethylene-based sealing film that facilitates the recycling of the OPP / PE sealing structure into the polyethylene recycling stream. When laminated with a suitably designed sealing film containing a compatibilizer, a stabilizer, or both, OPP can be compatible and recycled in the polyethylene recycling stream. When the sealing film contains a stabilizer, the resulting recycled polypropylene / polyethylene blend can be used for high-performance film extrusion.

[0025] The packaging films described in this article contain a significant proportion ( Right now The packaging film may contain more than 20%, 25%, 30%, 40%, 50%, or 60% polypropylene. The remainder of the packaging film may be polyethylene, or may be primarily polyethylene with other materials such as inks, adhesives, and barrier materials. Right now Polypropylene (EPO), polyamide, SiOx, etc., are immiscible with polyethylene and are therefore generally unacceptable in polyolefin recycling streams, including those containing melted and blended polymer materials. The inventors' research has yielded a surprising effect: by introducing specific compatibilizers into the structure, packaging film structures containing a significant proportion of polypropylene can be recycled in polyolefin recycling streams.

[0026] The properties of immiscible polymer blends depend on factors such as the droplet size of the dispersed (minor) phase and interfacial adhesion. Larger droplet sizes result in reduced light scattering, decreasing the blend's transparency. Low interfacial adhesion reduces strength properties and promotes cavitation during deformation operations such as thermoforming and uniaxial or biaxial stretching. Immiscible polymers can lead to less than ideal appearance and / or mechanical properties in articles made from such blends. To improve transparency and strength, it is generally desirable to maintain a stable distribution of small droplets within the multiphase polymer blend.

[0027] When thermodynamically immiscible polymers are blended in a mixing device and the elongation stress exceeds the elastic limit of the secondary polymer fractions, these secondary fractions break down into droplets, which become the dispersed phase of the multiphase system. The mixing device can utilize moving elements (…). For example (extruder), or it can be a stationary type (extruder). For example (Static mixer).

[0028] The deformation and breakup of viscous droplets in a flow field are controlled by the capillary number (Ca). The capillary number compares the relative strength of viscous stress (which tends to cause droplet elongation) and interfacial stress (the surface tension effect that tends to cause droplet spherical shape). When the capillary number reaches a critical value, viscous stress dominates, and the interfacial stress is not large enough to prevent droplet breakup. That is, surface tension is no longer able to maintain a spherical droplet, so the droplet elongates and eventually breaks up into smaller units.

[0029] Because smaller droplets create more interfaces, increasing the interfacial area, droplet breakup increases the system's free energy. As the polymer blend leaves the strongly mixed zone of the mixing apparatus (i.e., entering a region of lower elongation stress), droplet collisions lead to coalescence, reducing the total interfacial area and consequently lowering the system energy. Therefore, some of the transparency and strength benefits provided by strong mixing are lost. To minimize coalescence and maintain small droplets, compatibilizers are used to influence polymer interactions at the phase interfaces. Successful compatibilizers exhibit affinity for both phases. These affinityes can be chemical (…). For example Maleic anhydride-modified compatibilizer reacts with amine functional groups in polymer droplets ( For example Dow Retain 3000 used in PE / polyamide systems), or physical ( For example The compatibilizer chain becomes entangled with the droplet and / or the continuous phase ( For example (PE / PP block copolymers used in PE / PP systems). Ideally, compatibilizers prevent the aggregation of dispersed droplets and maintain a stable multiphase polymer system.

[0030] As used herein, the term "recyclable" is intended to indicate that the film can be transformed into a new, useful article by means of reprocessing in a polyolefin recycling stream. Reprocessing may involve washing, separation, melting, and molding, as well as many other steps. Typically, when plastic packaging is reprocessed, the material is mechanically shredded into small pieces and then melted to be reshaped into a new product. If multiple incompatible materials are present in the packaging, interactions occur during reprocessing, resulting in gels, brittle materials, poor appearance, and products that are generally unusable or of poor quality. The use of the term "recyclable" indicates that these disadvantages are generally not present. Qualification for recyclable materials is not regulated by any particular agency but may be obtained from specific groups such as the Association of Plastic Recyclers (APR) in the United States and Canada and How2Recycle™. The recyclable films disclosed herein are suitable for "store drop-off" recycling streams common in the United States, Canada, and the United Kingdom. These streams accept: 100% polyethylene bags, wraps, and films; very close to 100% polyethylene bags, wraps, and How2Recycle-approved polyethylene-based carrier packaging (with or without compatibilizer technology). Introducing recyclable membranes into any of these recycling pathways through reprocessing should not require additional compatibilizers. As used herein, the term "polyolefin recycling stream" refers to an industrial process of reprocessing from which the resulting product can be reformulated into a new product. Polyolefin recycling streams can be specifically used for polyethylene (PE). Right now polyethylene recycling stream), polypropylene ( Right now , a blend of polypropylene recycled stream or polyolefin.

[0031] The packaging film disclosed herein may be free of materials that contaminate polyolefin recycled streams. In particular, the packaging film may be free of polyamide (PA), ethylene vinyl alcohol copolymer (EVOH), and / or metal foil (…). Right now (Aluminum foil with a thickness greater than 5 micrometers). In some packaging films, polymers (such as PA and EVOH) may be present, but at low levels, such as less than 5% by weight of the entire packaging film.

[0032] Figure 1 An embodiment of a packaging film 100 including an oriented polypropylene film 10 coupled to a polyethylene film 12 is shown.

[0033] As used herein, the term "packaging film" refers to a film capable of being shaped into packaging. Packaging films can be flexible. Flexible packaging films can be bent or flexed into a shape and then bonded to themselves or other packaging components to form a cavity and substantially maintain its shape. A product can be contained within said cavity. Packaging films can form an airtight seal and provide oxygen and / or moisture barrier properties. Packaging films have two outer surfaces defined by length and width. Packaging films can have a thickness ranging from 15 micrometers to 200 micrometers or any range thereof.

[0034] Oriented polypropylene (OPP) films can be uniaxially or biaxially oriented. Oriented POP films can be of any standard type, including but not limited to transparent, white, cavitated, heat-sealable, matte, glossy, and treated on one or both sides. Oriented POP films can have a thickness ranging from 5 micrometers to 50 micrometers or any range thereof. Oriented POP films can have a propylene content ranging from 50% to 100% or 80% to 100% by weight. Oriented POP films can have a propylene content of 100% by weight. Oriented POP films can have a core comprising homopolymer polypropylene and a polypropylene copolymer surface layer.

[0035] Oriented polypropylene films can be printed so that ink is present on one or both surfaces. Ink can be located on the surface of the oriented polypropylene film between the oriented polypropylene film and the polyethylene film.

[0036] As used herein, the term "membrane" refers to a web constructed of one or more layers and / or membranes, all of which are adjacent to and connected to each other. A membrane can be described as having a thickness that is insignificant compared to its length and width. A membrane has two main surfaces whose areas are defined by its length and width. As used herein, the term "layer" refers to a building block of a membrane. As used herein, 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. A layer may be continuous with the membrane, or it may be discontinuous or patterned. A layer has a thickness (z direction) that is insignificant compared to its length and width (xy direction), and is therefore defined as having two main surfaces whose areas are defined by the length and width of the layer.

[0037] As used herein, "polyethylene film" can be a single-layer or multi-layer film having a composition of at least 50%, at least 70%, or at least 90% polyethylene by weight. The polyethylene film can be unoriented and produced by blown film or cast film processes. The polyethylene film can be uniaxially oriented (MDOPE). The polyethylene film can be biaxially oriented (BOPE). The polyethylene film can have a thickness ranging from 25 micrometers to 200 micrometers or any range thereof. The polyethylene film can be transparent or white. The polyethylene film can be heat-sealed.

[0038] As described herein, films can be oriented. Orientation can be the result of uniaxial orientation (longitudinal or transverse) or biaxial orientation (longitudinal and transverse) stretching of the film, thereby increasing the longitudinal and / or transverse dimensions and subsequently reducing the thickness of the material. Biaxial orientation can be imparted to the film simultaneously or continuously. The film is stretched in either or both directions at a temperature just below the melting temperature of the polymer in the film. In this way, stretching “orients” the polymer chains, thereby altering the physical properties of the film. Simultaneously, stretching thins the film. The resulting oriented film is thinner and can exhibit significant changes in mechanical properties such as toughness, heat resistance, stiffness, tear strength, and barrier properties. Orientation is typically achieved through double-bubble or triple-bubble processes, through tenter frame processes, or through MDO processes using heated rollers. Typical blown film processes or cast film processes do impart some stretch to the film, but not enough to be considered oriented as described herein. Oriented films can be heat-set after orientation ( Right now Annealing) allows it to transform during the cooking of the membrane composite ( Right now During printing or lamination or the use of the laminate ( Right now The dimensions are relatively stable under elevated temperature conditions that may be experienced during heat sealing or retort sterilization. As used herein, the term "unoriented" or the phrase "non-oriented" refers to a single-layer or multi-layer film, sheet, or web that is substantially not oriented after extrusion. A film is non-oriented if a layer that is part of a film or each of the layers in the film is substantially not oriented after extrusion.

[0039] The polyethylene film may contain a compatibilizer selected from the group consisting essentially of: propylene / ethylene copolymers, 1-butene-rich 1-butene / ethylene plastomers, polypropylene multiphase olefin copolymers, olefin block copolymers, hydrogenated styrene-butadiene-styrene block copolymers, ethylene propylene rubber, EPDM rubber, and combinations thereof; or a stabilizer selected from the group consisting essentially of: homogeneous branched linear ethylene polymers, heterogeneous branched linear ethylene polymers, and combinations thereof. The polyethylene film may contain both a compatibilizer and a stabilizer.

[0040] The compatibilizer may be selected from the group consisting essentially of: propylene / ethylene copolymers, polypropylene multiphase olefin copolymers, ethylene propylene rubber, ethylene propylene diene monomer (EPDM) rubber, and combinations thereof. The compatibilizer may be a propylene-rich propylene / ethylene copolymer. The compatibilizer may be a propylene / α-olefin copolymer. The stabilizer may be a homogeneous branched linear ethylene polymer. The stabilizer may be an ethylene / hexene copolymer or an ethylene / octene copolymer. As used herein, the polymer layer comprises at least one compatibilizer selected from the list of propylene / ethylene copolymers, 1-butene-rich 1-butene / ethylene plastomers, polypropylene multiphase olefin copolymers, olefin block copolymers, hydrogenated styrene-butadiene-styrene block copolymers, ethylene propylene rubber, ethylene propylene diene monomer (EPDM) rubber, and combinations thereof.

[0041] Preferably, the compatibilizer has a composition comprising both propylene and ethylene. In some embodiments of the packaging film, the polymer layer comprises at least one compatibilizer selected from the list of propylene / ethylene copolymers, polypropylene multiphase olefin copolymers, ethylene propylene rubber, EPDM rubber, and combinations thereof. In some embodiments of the packaging film, the polymer layer comprises at least one compatibilizer selected from propylene / ethylene copolymers and polypropylene multiphase olefin copolymers. In some embodiments, the compatibilizer may be a propylene-rich copolymer (… Right now (More than 50% of the bonds are propylene).

[0042] Propylene / ethylene copolymers can be propylene / α-olefin copolymers. Examples of propylene-rich propylene / ethylene copolymers include elastomers (such as Dow Versify™ 3401 or 3300 and ExxonMobil Vistamaxx 6102 and 6202) and plasmons (such as Dow Versify™ 3000).

[0043] Propylene-ethylene copolymers can be propylene-rich propylene / ethylene / butene terpolymers. Examples of propylene-rich propylene / ethylene / butene terpolymers include Lyondell Bassell Adsyl 5C 30F and 7416 XCP.

[0044] Examples of 1-butene-rich 1-butene / ethylene copolymers include Mitsui TAFMER BL3110 or BL3450.

[0045] The polypropylene multiphase olefin copolymers described herein preferably have a polypropylene matrix (55% to 90% by weight) and an elastomer (10% to 45% by weight), such as ethylene / propylene copolymers or C4 to C10 α-olefin copolymers.

[0046] Olefin block copolymers can be polypropylene-based olefin block copolymers, such as Dow INTUNE™, or can have alternating blocks with rigid and elastomeric segments, such as Dow INFUSE™.

[0047] Olefin block copolymers can be triblock or multiblock.

[0048] Examples of hydrogenated styrene-butadiene-styrene block copolymers (SEBS) include resins available in the Kraton CirKular+™ product line.

[0049] Ethylene propylene rubber (EPR) as described herein preferably has a polyethylene component (50% to 80% by weight) and a polypropylene component (20% to 50% by weight), such as a random rubber copolymer of ethylene and propylene.

[0050] Examples of ethylene propylene diene monomer (EPDM) rubber include ExxonMobil Vistalon™ and Dow NORDEL™.

[0051] The packaging film composition may contain more than 6%, 8%, 10%, 12%, or 14% compatibilizer by weight. The packaging film composition may contain less than 40%, 35%, or 30% compatibilizer by weight. For example, the packaging film composition may contain compatibilizer in the range of 10% to 35% by weight.

[0052] The theoretical function of stabilizers is to counteract the negative impacts of incompatibility in blends of mixed olefins (polyethylene and polypropylene). Stabilizers can “build back” or otherwise improve the physical properties of blends to produce higher quality films containing recycled blends. As used herein, “stabilizer” refers to a homogeneous branched linear ethylene polymer or a heterogeneous branched linear ethylene polymer. Stabilizers can be homogeneous branched linear ethylene / α-olefin copolymers, such as ethylene / hexene copolymers or ethylene / octene copolymers.

[0053] Examples of polymers that can be used as stabilizers include C6-mLLDPE, C6-LLDPE, C8-LLDPE, C8-ULDPE, and C8 plastomers. Examples of homogeneous branched linear ethylene polymers include ENGAGE™ grades 8100, 8180, and 8200 (C8 elastomers) available from Dow; Exact™ 0210 (C8 plastomer) from ExxonMobil; TAFMER® grades from Mitsui; and Queo® grades from Borealis. Examples of heterogeneous branched linear ethylene polymers include DOWLEX 3010 and ATTANE grades available from Dow.

[0054] As used in this article, the phrase "homogeneous polymer" refers to polymerization products with significant variations in both molecular weight and compositional distribution. Right now Typical polymers, for example, are prepared using conventional Ziegler-Natta catalysts. Heterogeneous polymers can be used in the various layers of the membranes used in this invention. Although there are a few exceptions (such as the TAFMER™ linear homogeneous ethylene and α-olefin copolymer produced by Mitsui using a Ziegler-Natta catalyst), heterogeneous polymers generally contain a relatively wide variety of chain lengths and comonomer percentages.

[0055] As used herein, the phrase "homogeneous polymer" refers to a polymerization product with a relatively narrow molecular weight distribution and a relatively narrow compositional distribution. Homogeneous polymers differ structurally from heterogeneous polymers because they exhibit a relatively uniform sequence of comonomers within the chain, a mirror image of the sequence distribution across all chains, and a similarity in chain length. Right now Narrower molecular weight distribution. Furthermore, homogeneous polymers are typically prepared using metallocene or other single-site type catalysts instead of Ziegler-Natta catalysts.

[0056] More specifically, homogeneous ethylene and α-olefin copolymers can be characterized by one or more methods known to those skilled in the art, such as molecular weight distribution (Mw / Mn), compositional distribution width index (CDBI), narrow melting point range, and single melting point behavior. Molecular weight distribution (Mw / Mn), also known as polydispersity, can be determined by gel permeation chromatography. The homogeneous ethylene and α-olefin copolymers (Mw / Mn) used in this invention typically have a Mw / Mn of less than 2.7; preferably from about 1.9 to about 2.5; more preferably from about 1.9 to about 2.3. The compositional distribution width index (CDBI) of such homogeneous ethylene and α-olefin copolymers will typically be greater than about 70%. CDBI is defined as the comonomer content being 50% of the median total molar comonomer content (…). Right now The composition distribution width index (CDBI) is the weight percentage of copolymer molecules within the copolymer (10% of the comonomer or oriented polypropylene film). Linear polyethylene without comonomers is defined as 100%. The composition distribution width index (CDBI) is determined via temperature elution fractionation (TREF) technology. CDBI determination clearly distinguishes between homogeneous copolymers used in this invention (e.g., narrow composition distributions assessed by CDBI values ​​typically greater than 70%) and commercially available VLDPEs typically having wide composition distributions assessed by CDBI values ​​typically less than 55%. The CDBI of the copolymer can be readily calculated from data obtained using techniques known in the art (e.g., temperature elution fractionation as described, for example, in Wild et al., J. Poly. Sci. Poly. Phys. Ed., Vol. 20, p.441 (1982)). Preferably, the homogeneous ethylene and α-olefin copolymer has a CDBI greater than about 70%. Right now CDBI is approximately 70% to 99%. Typically, it is associated with "homogeneous copolymers" (…). Right nowCompared to polymers with a CDBI of less than 55%, the homogeneous ethylene and α-olefin copolymers in the multilayer films of the present invention also exhibit a relatively narrow melting point range. Preferably, the homogeneous ethylene and α-olefin copolymers exhibit substantially single melting point characteristics, having a peak melting point (Tm) of about 60°C to about 110°C, as determined by differential scanning calorimetry (DSC). Preferably, the homogeneous copolymer has a DSC peak Tm of about 80°C to about 105°C. As used herein, the phrase "substantially single melting point" means that, as determined by DSC analysis, at least about 80% by weight of the material corresponds to a single Tm peak at a temperature in the range of about 60°C to about 110°C, and substantially no substantial fraction of the material has a peak melting point exceeding about 115°C. The reported melting information is second melting data. Right now The sample was heated to a temperature below its critical range at a programmed rate of 10°C / min. The sample was then reheated at a programmed rate of 10°C / min (second melting). The presence of a higher melting peak is detrimental to film properties such as haze and reduces the chance of a meaningful reduction in the final film's sealing temperature.

[0057] Homogeneous ethylene and α-olefin copolymers can typically be prepared by copolymerizing ethylene with any one or more α-olefins. Preferably, the α-olefin is a C4-C2 α-monoolefin, more preferably a C4-C8 α-monoolefin. Even more preferably, the α-olefin comprises at least one member selected from butene-1, hexene-1, and octene-1. Right now 1-Butene, 1-hexene, and 1-octene, respectively. Most preferably, the α-olefin comprises octene-1 and / or a blend of hexene-1 and butene-1.

[0058] The polyethylene film can be a single layer having a homogeneous composition comprising a compatibilizer and / or a stabilizer. The polyethylene film can also be a multilayer film having one or more layers comprising a compatibilizer and / or one or more layers comprising a stabilizer. Any one or more layers of the polyethylene film may contain both a compatibilizer and a stabilizer.

[0059] As used herein, the phrase "ethylene and α-olefin copolymer" refers to heterogeneous materials such as linear low-density polyethylene (LLDPE), linear medium-density polyethylene (LMDPE), and very low-density and ultra-low-density polyethylene (VLDPE and ULDPE); and homogeneous polymers such as metallocene-catalyzed EXACT™ linear homogeneous ethylene and α-olefin copolymer resins available from Exxon, unit-point AFFFNITY™ linear homogeneous ethylene and α-olefin copolymer resins available from Dow, and TAFMER™ linear homogeneous ethylene and α-olefin copolymer resins available from Mitsui. All these materials typically comprise copolymers of ethylene with one or more comonomers selected from C4 to C10 α-olefins (such as butene-1, hexene-1, octene-1, etc.), wherein the molecules of said copolymers contain long chains with relatively few side-chain branches or crosslinking structures. Heterogeneous ethylene and α-olefin copolymers, commonly referred to as LLDPE, typically have a density of about 0.915 g / cm³. 3 Approximately 0.930 g / cm³ 3 Within this range, heterogeneous ethylene and α-olefin copolymers, commonly referred to as LMDPE, typically have a density of about 0.930 g / cm³. 3 To approximately 0.945 g / cm 3 Within this range, while those copolymers typically identified as VLDPE or ULDPE have a density of less than about 0.915 g / cm³. 3 .

[0060] The packaging film may have a composition comprising 15% to 75%, 20% to 60%, or 20% to 50% polypropylene by weight. The packaging film may have a composition comprising 10% to 35% compatibilizer and / or stabilizer by weight. The packaging film may have a composition comprising 80% to 99% polyolefin by weight.

[0061] Figure 2 An embodiment of packaging film 200 is shown, which includes an alignment film 20, a multilayer film 22, and an adhesive layer 24 connecting the alignment film 20 to the multilayer film 22. The packaging film 200 of this embodiment is similar to... Figure 1 The packaging film 100 of the embodiment shown in the figure is for... Figure 1 The options and features described for packaging film 100 also apply to packaging film 200. The orientation film 20 of this embodiment is similar to… Figure 1 The oriented polypropylene film 10 of the embodiment shown is illustrated, and the options and features described for the oriented polypropylene film 10 also apply to the oriented film 20. Similarly, the multilayer film 22 of this embodiment is similar to... Figure 1 The polyethylene film 12 of the embodiment shown in the figure, and the options and features described for the polyethylene film 12 also apply to the multilayer film 22.

[0062] As used herein, the term "joint" refers to two components directly or indirectly connected to each other. The term "adhesive layer" refers to a layer or material placed on one or more layers or films to facilitate adhesion between that layer and another surface. Preferably, the adhesive layer is positioned between two layers of a multilayer film to hold the two layers in place relative to each other and prevent undesirable delamination. Unless otherwise stated, the adhesive layer may have any suitable composition that provides a desired level of adhesion to one or more surfaces in contact with the adhesive layer material. The adhesive layer may be an adhesive applied by a lamination process (…). Right now (Single-component, two-component, solvent-free, solvent-based, water-based or energy-curing adhesives), or polyethylene laminates applied by an extrusion lamination process.

[0063] Figure 3 An embodiment of a packaging film 300 comprising a biaxially oriented polypropylene film 30 and a multilayer polyethylene film 32 is shown. The packaging film 300 of this embodiment is similar to... Figure 1 The packaging film 100 of the embodiment shown in the figure is for... Figure 1 The options and features described for packaging film 100 also apply to packaging film 300. The biaxially oriented polypropylene film 30 of this embodiment is similar to… Figure 1 The oriented polypropylene film 10 of the embodiment shown is illustrated, and the options and features described for the oriented polypropylene film 10 also apply to the biaxially oriented polypropylene film 30. Similarly, the multilayer polyethylene film 32 of this embodiment is similar to... Figure 1 The polyethylene film 12 of the embodiment shown herein, and the options and features described for the polyethylene film 12 also apply to the multilayer polyethylene film 32.

[0064] Figure 4 An embodiment of a packaged product 1000 is shown, comprising a packaging film 400 formed into a package and a product (not shown) enclosed within the package. The package can take any form, such as a stand-up pouch or tray / lid, and may include other packaging components in addition to the packaging film. The product enclosed within the package made of the packaging film is not limited. The product can be of a type that benefits from moisture, oxygen, or light protection provided by the packaging film. Examples of products include food items such as potato chips, crackers, snacks, cereals, dry powders, sweets, candies, or nut butters. Examples of products include cosmetics such as loose powder, facial tissues, or detergents. Examples of products include household / industrial products such as cleaning wipes, powdered cleaners, or pet food.

[0065] Any packaging film implementation may also include a barrier layer, such as, but not limited to, EVOH, a metallized layer, or an inorganic oxide layer. The packaging film may also include other layers or materials, provided that the introduction of such materials does not impede the recyclability of the packaging film.

[0066] Predictive Packaging Film Examples The inventors have conceived various embodiments of the packaging film, including but not limited to: OPP / ink / adhesive layer / PE sealant; OPP / ink / polyethylene laminate / PE sealant; OPP / Ink / Adhesive Layer / PE-EVOH-PE Sealant; OPP / ink / polyethylene laminate / PE-EVOH-PE sealant; OPP / ink / adhesive layer / MDOPE sealant; and BOPE / adhesive layer / metallized OPP / adhesive layer / PE sealant.

[0067] Here, OPP refers to standard biaxially oriented polypropylene film that has been printed with ink, and the listed sealant contains compatibilizers and / or stabilizers as defined herein.

[0068] Packaging film examples and data Several layered compounds were prepared for testing.

[0069] Multilayer sealed films were prepared using a blown film process, each film comprising either sealant A or sealant B. Sealant A contained 46% C4-LLDPE, 28% MDPE, 17.6% C6-mLLDPE, and 8.4% LDPE. Sealant B contained 56% C6-LLDPE, 22% C8-LLDPE, 11.5% C6-mLLDPE, 9% C8-plasticizer, and 1.5% LDPE.

[0070] Control membrane: An all-polyethylene membrane was prepared for comparison. This type of membrane structure is recyclable in the polyethylene recycling stream but does not possess the performance properties of membranes containing oriented polypropylene. The control membrane has the structure of 1.0 mil MDO PE membrane / ink / adhesive / 1.5 mil sealant B. The control membrane has a composition containing 0% polypropylene.

[0071] Membrane 1: The structure of membrane 1 is 70 g a (17.8 microns) BOPP / ink / adhesive / 2 mil sealant A. Membrane 1 has a composition containing approximately 25% polypropylene by weight.

[0072] Membrane 2: The structure of membrane 2 is 70 g a BOPP / ink / adhesive / 2 mil sealant B. Membrane 2 has a composition containing approximately 25% polypropylene by weight.

[0073] Membrane 3: The structure of membrane 3 is 70 g a BOPP / ink / adhesive / 1.5 mil sealant B. Membrane 3 has a composition containing approximately 30% polypropylene by weight.

[0074] The BOPP membrane used has a homopolymer polypropylene core and a polypropylene copolymer surface layer.

[0075] Apply the ink to the BOPP film using 3% dry ink solids at a rate slightly above 2 lbs / ream.

[0076] A recycling suitability assessment was conducted according to the standard APR (Association of Plastic Recyclers) protocol. The assessment included both a 50 / 50 blend of the tested membrane and a control material (reprocessed C4-LLDPE, MI=1, density=0.918) and a 100% test membrane. Testing included the preparation of the membrane from the blend / recycled materials and physical testing of the resulting membranes. A baseline for the test results was generated using the control membrane, and the results are shown as the difference compared to the control. APR guidance states that the physical properties of the membrane should not decrease by more than 25% relative to the control membrane.

[0077] Impact strength is measured as dart impact strength using ASTM D7192 with a 0.75-inch radius probe, a velocity of 10.63 ± 0.02 ft / sec, and a weight of 10.55 lbs. MD and TD tear data are Elmendorf tear strengths, measured according to ASTM D1922 with MD using a 200 g pendulum and TD using a 1,600 g pendulum.

[0078] Table 1 below compares membrane 1 and membrane 2. We observe that the negative impact of polypropylene content in sealant A is significantly greater than that in sealant B, especially when polypropylene is contained at a higher ratio. Specifically, using the lower-performance sealant A results in a significant reduction in MD and TD tear strength, as well as impact strength.

[0079] Table 1: Changes in membrane properties relative to the control, values ​​are percentage changes relative to the control membrane. Table 2 below compares membrane 2 and membrane 3. We see that the physical properties decrease with increasing polypropylene content. However, in some cases, membrane 3 can be considered recyclable because the reduction in performance properties is greater than 25% only in tests using 100% of this membrane.

[0080] Table 2: Changes in membrane properties relative to the control, values ​​are percentage changes relative to the control membrane. Implementation Scheme 1: A packaging film comprising: an oriented polypropylene film coupled to a polyethylene film; wherein the polyethylene film comprises at least one of a) a compatibilizer and b) a stabilizer, the compatibilizer being selected from the group consisting essentially of: propylene / ethylene copolymers, 1-butene-rich 1-butene / ethylene plastomers, polypropylene multiphase olefin copolymers, olefin block copolymers, hydrogenated styrene-butadiene-styrene block copolymers, ethylene propylene rubber, EPDM rubber, and combinations thereof, and the stabilizer being selected from the group consisting essentially of: homogeneous branched linear ethylene polymers, heterogeneous branched linear ethylene polymers, and combinations thereof.

[0081] Implementation Scheme 2: The packaging film of Implementation Scheme 1, wherein the oriented polypropylene film is uniaxially oriented.

[0082] Implementation Scheme 3: The packaging film of Implementation Scheme 1, wherein the oriented polypropylene film is biaxially oriented.

[0083] Implementation Scheme 4: The packaging film of any one of Implementation Schemes 1 to 3, wherein the polyethylene film comprises at least one compatibilizer and at least one stabilizer.

[0084] Implementation Scheme 5: A packaging film of any one of Implementation Schemes 1 to 4, further comprising a composition comprising polypropylene in the range of 15% to 75% by weight.

[0085] Implementation Scheme 6: The packaging film of any one of Implementation Schemes 1 to 5 further has a thickness in the range of 15 micrometers to 100 micrometers.

[0086] Implementation Scheme 7: The packaging film of any one of Implementation Schemes 1 to 6, wherein the polyethylene film comprises one or more layers.

[0087] Implementation Scheme 8: The packaging film of any one of Implementation Schemes 1 to 7, wherein the polyethylene film is oriented.

[0088] Implementation Scheme 9: The packaging film of any one of Implementation Schemes 1 to 7, wherein the polyethylene film is non-oriented.

[0089] Implementation Scheme 10: The packaging film of any one of Implementation Schemes 1 to 9, wherein the compatibilizer is a propylene-rich propylene / ethylene copolymer.

[0090] Implementation Scheme 11: A packaging film of any one of Implementation Schemes 1 to 10, wherein the compatibilizer is a propylene / α-olefin copolymer.

[0091] Implementation Scheme 12: A packaging film of any one of Implementation Schemes 1 to 11, wherein the stabilizer is a homogeneous branched linear ethylene polymer.

[0092] Implementation Scheme 13: The packaging film of Implementation Scheme 12, wherein the stabilizer is an ethylene / hexene copolymer or an ethylene / octene copolymer.

[0093] Implementation Scheme 14: A packaging film suitable for recycling in a polyolefin recycling stream, comprising: an oriented film comprising 80% to 100% polypropylene by weight; a multilayer film comprising 50% to 100% polyethylene by weight; and an adhesive layer connecting the oriented film to the multilayer film; wherein the multilayer film comprises at least one of a compatibilizer and a stabilizer; wherein the compatibilizer is selected from the group consisting substantially of: propylene / ethylene copolymers, 1-butene-rich 1-butene / ethylene plastomers, polypropylene multiphase olefin copolymers, olefin block copolymers, hydrogenated styrene-butadiene-styrene block copolymers, ethylene propylene rubber, EPDM rubber, and combinations thereof; and the stabilizer is selected from the group consisting substantially of: homogeneous branched linear ethylene polymers, heterogeneous branched linear ethylene polymers, and combinations thereof.

[0094] Implementation Scheme 15: The packaging film of Implementation Scheme 14, further comprising a composition comprising the compatibilizer in the range of 10% to 35% by weight.

[0095] Implementation Scheme 16: The packaging film of Implementation Scheme 14 or 15, wherein the multilayer film is oriented.

[0096] Implementation Scheme 17: The packaging film of Implementation Scheme 14 or 15, wherein the multilayer film is non-oriented.

[0097] Implementation Scheme 18: A packaging film of any one of Implementation Schemes 14 to 17, further comprising a second adhesive layer that connects a biaxially oriented polyethylene film to the oriented film opposite the multilayer film, and the packaging film having a thickness in the range of 25 micrometers to 250 micrometers.

[0098] Implementation Scheme 19: The packaging film of any one of Implementation Schemes 14 to 18, further comprising ink attached to the orientation film.

[0099] Implementation Scheme 20: The packaging film of any one of Implementation Schemes 1-17 or 19, further having a thickness in the range of 15 to 100 micrometers.

[0100] Implementation Scheme 21: A packaging film of any one of Implementation Schemes 1 to 20, wherein the film composition comprises polyolefin in the range of 80% to 99% by weight.

[0101] Implementation Scheme 22: A packaging film suitable for recycling in a polyolefin recovery stream, comprising a biaxially oriented polypropylene film coupled to a multilayer polyethylene film; wherein the multilayer polyethylene film comprises at least one of a compatibilizer and a stabilizer; and wherein the compatibilizer is selected from the group consisting substantially of: propylene / ethylene copolymers, 1-butene-rich 1-butene / ethylene plastomers, polypropylene multiphase olefin copolymers, olefin block copolymers, hydrogenated styrene-butadiene-styrene block copolymers, ethylene propylene rubber, EPDM rubber, and combinations thereof; wherein the stabilizer is selected from the group consisting substantially of: homogeneous branched linear ethylene polymers, heterogeneous branched linear ethylene polymers, and combinations thereof; wherein the packaging film comprises a composition comprising at least one of a compatibilizer and a stabilizer in the range of 10% to 35% by weight.

[0102] Implementation Scheme 23: The packaging film of any one of Implementation Schemes 1 to 22, wherein the packaging film is recyclable in the polyethylene recycling stream.

[0103] Implementation Scheme 24: A packaging film of any one of Implementation Schemes 1 to 23, wherein the compatibilizer is selected from the group consisting substantially of: propylene / ethylene copolymers, polypropylene multiphase olefin copolymers, ethylene propylene rubber, EPDM rubber, and combinations thereof.

[0104] Implementation Scheme 25: A packaged product comprising: a packaging film of any one of Implementation Schemes 1 to 24, and a product; wherein the packaging film is sealed to form a package, and the product is enclosed within the package.

Claims

1. A packaging film comprising: Oriented polypropylene film attached to polyethylene film; The polyethylene film therein comprises at least one of a) a compatibilizer and b) a stabilizer, wherein the compatibilizer is selected from the group consisting essentially of: propylene / ethylene copolymers, 1-butene-rich 1-butene / ethylene plastomers, polypropylene multiphase olefin copolymers, olefin block copolymers, hydrogenated styrene-butadiene-styrene block copolymers, ethylene propylene rubber, EPDM rubber, and combinations thereof, and the stabilizer is selected from the group consisting essentially of: homogeneous branched linear ethylene polymers, heterogeneous branched linear ethylene polymers, and combinations thereof.

2. The packaging film according to claim 1, wherein the oriented polypropylene film is uniaxially oriented.

3. The packaging film according to claim 1, wherein the oriented polypropylene film is biaxially oriented.

4. The packaging film according to claim 1, wherein the polyethylene film comprises at least one compatibilizer and at least one stabilizer.

5. The packaging film of claim 1, further comprising a composition comprising polypropylene in the range of 15% to 75% by weight.

6. The packaging film according to claim 1, further comprising a thickness in the range of 15 micrometers to 100 micrometers.

7. The packaging film according to claim 1, wherein the polyethylene film comprises one or more layers.

8. The packaging film according to claim 1, wherein the polyethylene film is oriented.

9. The packaging film according to claim 1, wherein the polyethylene film is non-oriented.

10. The packaging film according to claim 1, wherein the compatibilizer is a propylene-rich propylene / ethylene copolymer.

11. The packaging film according to claim 1, wherein the compatibilizer is a propylene / α-olefin copolymer.

12. The packaging film according to claim 1, wherein the stabilizer is a homogeneous branched linear ethylene polymer.

13. The packaging film according to claim 12, wherein the stabilizer is an ethylene / hexene copolymer or an ethylene / octene copolymer.

14. A packaging film suitable for recycling in a polyolefin recycling stream, comprising: An orientation film comprising polypropylene in the range of 80% to 100% by weight; A multilayer film comprising, by weight, 50% to 100% polyethylene; and The alignment film is attached to the adhesive layer of the multilayer film; The multilayer film comprises at least one of a compatibilizer and a stabilizer; The compatibilizer is selected from the group consisting essentially of: propylene / ethylene copolymers, 1-butene-rich 1-butene / ethylene plastomers, polypropylene multiphase olefin copolymers, olefin block copolymers, hydrogenated styrene-butadiene-styrene block copolymers, ethylene propylene rubber, EPDM rubber, and combinations thereof; and The stabilizer is selected from the group consisting essentially of homogeneous branched linear ethylene polymers, heterogeneous branched linear ethylene polymers, and combinations thereof.

15. The packaging film of claim 14, further comprising a composition comprising the compatibilizer in the range of 10% to 35% by weight.

16. The packaging film of claim 14, wherein the multilayer film is oriented.

17. The packaging film of claim 14, wherein the multilayer film is non-oriented.

18. The packaging film of claim 14, further comprising a second adhesive layer that bonds the biaxially oriented polyethylene film to the oriented film opposite the multilayer film, and the packaging film having a thickness in the range of 25 micrometers to 250 micrometers.

19. The packaging film of claim 14, further comprising ink coupled to the orientation film.

20. The packaging film according to claim 14, further comprising a thickness in the range of 15 to 100 micrometers.

21. The packaging film of claim 14, wherein the film composition comprises 80% to 99% polyolefin by weight.

22. A packaging film suitable for recycling in a polyolefin recycling stream, comprising a biaxially oriented polypropylene film coupled to a multilayer polyethylene film; The multilayer polyethylene film contains at least one of a compatibilizer and a stabilizer; and The compatibilizer is selected from the group consisting essentially of: propylene / ethylene copolymers, 1-butene-rich 1-butene / ethylene plasmons, polypropylene multiphase olefin copolymers, olefin block copolymers, hydrogenated styrene-butadiene-styrene block copolymers, ethylene propylene rubber, EPDM rubber, and combinations thereof. The stabilizer is selected from the group consisting essentially of homogeneous branched linear ethylene polymers, heterogeneous branched linear ethylene polymers, and combinations thereof. The packaging film comprises a composition comprising at least one of a compatibilizer and a stabilizer in the range of 10% to 35% by weight.

23. The packaging film of claim 1, wherein the packaging film is recyclable in the polyethylene recycling stream.

24. The packaging film of claim 1, wherein the compatibilizer is selected from the group consisting substantially of: propylene / ethylene copolymers, polypropylene multiphase olefin copolymers, ethylene propylene rubber, EPDM rubber, and combinations thereof.

25. A packaged product comprising: The packaging film according to claim 1, and the product; The packaging film is sealed to form a package, and the product is encapsulated within the package.

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