Breathable biaxially oriented polyethylene film

Abstract

Disclosed is a biaxially oriented polyethylene film comprising: from 25 wt% to 60 wt% of an ethylene-alpha-olefin copolymer comprising an ethylene monomer and a 1-octene or 1-hexene comonomer, and at least 50% of the amount of copolymer eluted between 65.0 DEG C and 95.0 DEG C in an elution curve obtained via iCCD and a molecular weight greater than 90,000 g / mol between 65.0 DEG C and 95.0 DEG C in the elution curve; and 40% to 75% by weight of a filler. The biaxially oriented film has a water vapor transmission rate of greater than 300 g / m2 / day at 40.0 DEG C and a relative humidity of 60%, and has an elongation at break of less than 200% in the machine direction and the transverse direction. Articles comprising the biaxially oriented polyethylene film are also disclosed.

Description

Technical Field

[0001] The present disclosure generally relates to biaxially oriented polyethylene films, and articles comprising the biaxially oriented polyethylene films.

[0002] introduction

[0003] Breathable films are used in a wide variety of applications, including fresh produce packaging, baby diapers, adult incontinence products, surgical gowns, and other hygiene and medical applications. Breathable films have a microporous morphology (i.e., micropores) to provide a water vapor transmission rate ("WVTR") that helps allow water vapor to pass through and eliminate condensation of water droplets. Breathability or WVTR is an important property of many breathable films because the film can act as a liquid barrier while allowing water vapor to pass through to provide benefits such as protection or comfort. For example, a breathable film used in plastic food packaging for fruit can help prevent water droplets from condensing on the fruit (causing fungal growth).

[0004] Breathable films are usually prepared in the following manner: fillers (e.g., CaCO3) are incorporated into polyolefin resins such as polyethylene or polypropylene, cast or blown films are prepared, and the cast or blown films are stretched or oriented by longitudinal orientation rollers via tentering or via meshing gears, thereby ring rolling or incrementally stretching the film in one or both of the longitudinal or transverse directions at a temperature below the melting point of the polyolefin resin. The generation of micropores is partly due to the addition of fillers to the polyolefin of the film. Post-extrusion processes, such as longitudinal orientation or the use of interdigitating, also help to produce micropores in the film by generating cavitation around filler particles at the interface of filler and polyolefin. The longitudinal tensile strength of the films currently produced is acceptable, but the transverse or cross-direction tensile strength may be weaker. This is the main obstacle to reducing the thickness of the film. The film with reduced thickness uses less plastic and has less impact on the environment. Therefore, there is a need for a film with improved transverse tensile strength and desired properties such as water vapor transmission rate, hydrostatic head and longitudinal tensile strength.

[0005] In the processing of breathable films, a relatively new material technology is biaxially oriented polyethylene (BOPE) film. Such BOPE films are formed by cast extrusion, then oriented in the machine direction (MD) in a tenter frame, and then oriented in the transverse direction (TD). Alternatively, this process can also be performed simultaneously. Summary of the invention

[0006] The present disclosure satisfies the aforementioned needs by providing biaxially oriented films having desirable and / or improved properties, including, for example, transverse tensile strength, longitudinal tensile strength, water vapor transmission rate, and hydrostatic head. In some aspects, the biaxially oriented films of the present disclosure can exhibit such improved and / or desirable properties when compared to existing film structures while also being able to reduce film thickness during processing.

[0007] A biaxially oriented film is disclosed herein. The biaxially oriented film comprises: a. 25 wt% to 60 wt% of an ethylene-α-olefin copolymer, which comprises i) ethylene monomer and 1-octene or 1-hexene comonomer, ii) at least 50 wt% of the copolymer amount eluted between 65.0°C and 95.0°C in an elution curve obtained by an improved comonomer composition distribution (iCCD) analysis method, and iii) a molecular weight (Mw) greater than 90,000 g / mol between 65.0°C and 95.0°C in an elution curve obtained by an improved comonomer composition distribution (iCCD) analysis method; and b. 40 wt% to 75 wt% of a filler; and wherein the film has a relative humidity of greater than 300 g / m at 40°C and 60%. 2 / day water vapor transmission rate, and has a breaking elongation of less than 200% in the longitudinal and transverse directions.

[0008] Also disclosed herein are articles.An article may comprise a biaxially oriented polyethylene film according to embodiments disclosed herein.

[0009] The present disclosure is described in more detail in the detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 The elution profiles of certain example polymers via iCCD are schematically depicted.

[0011] Figure 2 is in R 2 The relationship between the octene mol% and the elution temperature of the iCCD when the concentration of octene is 0.978. DETAILED DESCRIPTION

[0012] Breathable films can have a wide variety of applications, including, for example, fresh produce packaging, baby diapers, adult incontinence products, surgical gowns, and other hygiene and medical applications. However, the present disclosure can be implemented in different forms and should not be construed as being limited to the embodiments set forth in the present disclosure. Rather, these embodiments are provided to make the present disclosure comprehensive and complete and to fully convey the scope of the subject matter to those skilled in the art.

[0013] As used herein, the term "polymer" means a polymeric compound prepared by polymerizing monomers of the same or different types. The generic term polymer thus encompasses the term homopolymer (used to refer to polymers prepared from only one type of monomer) and the terms copolymer or interpolymer. Trace amounts of impurities (e.g., catalyst residues) may be incorporated into and / or within the polymer. The polymer may be a single polymer, a polymer blend, or a polymer mixture, including a mixture of polymers formed in situ during polymerization.

[0014] As used herein, the term "polyolefin" refers to polymers that comprise, in polymerized form, a majority amount of olefin monomer (eg, ethylene or propylene) (based on the weight of the polymer) and optionally may comprise one or more comonomers.

[0015] As used herein, the term "polyethylene" refers to a polymer comprising a major amount (>50 mol%) of units derived from ethylene monomers.

[0016] As used herein, the term "copolymer" refers to any polymer having two or more monomers.

[0017] The terms "comprising," "including," "having," and derivatives thereof are not intended to exclude the presence of any additional components, steps, or procedures, whether or not specifically disclosed. For the avoidance of any doubt, all compositions claimed through use of the term "comprising" may include any additional additives, adjuvants, or compounds, whether polymeric or otherwise, unless stated to the contrary. In contrast, the term "consisting essentially of excludes from the scope of any subsequently recited component, step, or procedure, except those that are not essential to operability. The term "consisting of excludes any ingredient, step, or procedure not specifically recited or listed.

[0018] Based on the gross weight of the biaxially oriented polyethylene film, the biaxially oriented polyethylene film may include 25% to 60% by weight (wt%) of ethylene-α-olefin copolymer and 40% to 75% by weight of filler. All individual values ​​and subranges of 25% to 60% by weight are disclosed and included herein. For example, based on the gross weight of the biaxially oriented polyethylene film, the biaxially oriented polyethylene film may include 25% to 55% by weight, 28% to 32% by weight, 30% to 50% by weight, 38% to 42% by weight, 35% to 55% by weight, 40% to 50% by weight, or 30% to 40% and 48% to 52% by weight of ethylene-α-olefin copolymer. All individual values ​​of 40% to 75% by weight of filler are also disclosed and included herein. For example, the biaxially oriented polyethylene film can comprise 40 wt % to 75 wt %, 45 wt % to 70 wt %, 45 wt % to 75 wt %, 68 wt % to 72 wt %, 58 wt % to 62 wt %, 48 wt % to 52 wt %, 50 wt % to 70 wt %, 50 wt % to 60 wt %, or 60 wt % to 70 wt % filler, based on the total weight of the biaxially oriented polyethylene film.

[0019] Biaxially oriented polyethylene film of ethylene-α-olefin copolymer

[0020] The biaxially oriented polyethylene film disclosed herein comprises an ethylene-α-olefin copolymer. The ethylene-α-olefin copolymer comprises an ethylene monomer and a 1-octene or 1-hexene comonomer. The ethylene / α-olefin copolymer can be an ethylene / 1-octene copolymer. The ethylene-α-olefin copolymer can be an ethylene / 1-hexene copolymer.

[0021] Based on the gross weight of ethylene-alpha-olefin copolymer, ethylene-alpha-copolymer can include 60 wt % to 95 wt % ethylene monomer and 5 wt % to 45 wt % 1-octene or 1-hexene comonomer.All individual values ​​and sub-ranges are disclosed and included.For example, based on the gross weight of ethylene-alpha-olefin copolymer, ethylene-alpha-copolymer can include 80 wt % to 97 wt % ethylene monomer and 3 wt % to 20 wt % 1-octene or 1-hexene comonomer.Ethylene-alpha-copolymer can include 85 wt % to 96 wt % ethylene monomer and 4 wt % to 15 wt % 1-octene or 1-hexene comonomer.Ethylene-alpha-copolymer can include 88 wt % to 98 wt % ethylene monomer and 2 wt % to 12 wt % 1-octene or 1-hexene comonomer. Ethylene-alpha-copolymer can comprise 86 wt % to 90 wt % ethylene monomer and 14 wt % to 10 wt % 1-octene or 1-hexene comonomer. Ethylene-alpha-copolymer can comprise 90 wt % to 94 wt % ethylene monomer and 6 wt % to 10 wt % 1-octene or 1-hexene comonomer. Ethylene-alpha-copolymer can comprise 91 wt % to 95 wt % ethylene monomer and 5 wt % to 9 wt % 1-octene or 1-hexene comonomer. Ethylene-alpha-copolymer can comprise 93 wt % to 97 wt % ethylene monomer and 3 wt % to 7 wt % 1-octene or 1-hexene comonomer.

[0022] In the elution curve obtained via the improved comonomer composition distribution (iCCD) analysis method, the ethylene-α-olefin copolymer contains at least 50 weight % of the copolymer eluted between 65.0° C. and 95.0° C. based on the total area of ​​the ethylene-α-olefin copolymer eluted during the iCCD analysis. In the elution curve obtained via the iCCD analysis method, the copolymer amount or weight percentage eluted between 65.0° C. and 95.0° C. is calculated based on the following test method. The elution curve obtained via iCCD can be found in Figure 1. The weight fraction of the material eluted between 65.0°C and 95.0°C can be directly calculated. It is obvious that the embodiments of the present invention have high weight % materials with extremely large Mw eluted between 65.0°C and 95.0°C (see Table 4). All individual values ​​and subranges of at least 50 weight % are disclosed and included herein. For example, in the elution curve obtained via an improved comonomer composition distribution (iCCD) analysis method, based on the total area of ​​the ethylene-α-olefin copolymer eluted during the iCCD analysis, the ethylene-α-olefin copolymer may contain at least 55 weight %, at least 60 weight %, at least 70 weight %, at least 80 weight % or at least 90 weight % of the copolymer amount eluted between 65.0°C and 95.0°C. In the elution curve obtained via an improved comonomer composition distribution (iCCD) analysis method, based on the total area of ​​the ethylene-α-olefin copolymer eluted during the iCCD analysis, the ethylene-α-olefin copolymer may include a copolymer amount eluted between 65.0°C and 95.0°C between 50% by weight and 95% by weight. All individual values ​​and subranges between 50% by weight and 90% by weight are disclosed and included herein. For example, in the elution curve obtained via an improved comonomer composition distribution (iCCD) analysis method, based on the total area of ​​the ethylene-α-olefin copolymer eluted during the iCCD analysis, the ethylene-α-olefin copolymer may include a copolymer amount eluted between 65.0°C and 95.0°C between 60% by weight and 85% by weight, 70% by weight and 80% by weight, 70% by weight and 74% by weight, 73% by weight and 77% by weight, 80% by weight and 84% by weight, or 88% by weight and 92% by weight.

[0023] Ethylene-alpha-olefin copolymer can be quantified by its temperature range in the elution curve obtained via improved comonomer composition distribution (iCCD) analysis method. Unless otherwise stated, any elution curve mentioned herein is an elution curve observed via iCCD. Ethylene-alpha-olefin copolymer can be "multimodal", meaning that they include at least two peaks in its elution curve. Some copolymers can be "bimodal", meaning that there are two main peaks. Ethylene-alpha-olefin copolymer can have a single peak between 65.0°C and 95.0°C. Based on the total area of ​​the ethylene-alpha-olefin copolymer eluted during the iCCD analysis, the copolymer eluted between 65.0°C and 95.0°C in the elution curve can include at least 50% by weight of ethylene-alpha-olefin copolymer. Based on the total area of ​​the ethylene-alpha-olefin copolymer eluted during the iCCD analysis, the copolymer eluted between 65.0°C and 95.0°C in the elution curve can include at least 60% by weight of ethylene-alpha-olefin copolymer. Based on the total area of ​​ethylene-α-olefin copolymers eluted during iCCD analysis, the copolymer eluted between 65.0°C and 95.0°C in the elution curve may contain at least 70% by weight of ethylene-α-olefin copolymers. Based on the total area of ​​ethylene-α-olefin copolymers eluted during iCCD analysis, the copolymer eluted between 65.0°C and 95.0°C in the elution curve may contain at least 80% by weight of ethylene-α-olefin copolymers. Based on the total area of ​​ethylene-α-olefin copolymers eluted during iCCD analysis, the copolymer eluted between 65.0°C and 95.0°C in the elution curve may contain no more than 99% by weight of ethylene-α-olefin copolymers.

[0024] In the elution curve obtained via the improved comonomer composition distribution (iCCD) analysis method, the ethylene-alpha-olefin copolymer can have a molecular weight (Mw) greater than 90,000 g / mol between 65.0°C and 95.0°C. The molecular weight (Mw) of the copolymer eluted between 65.0°C and 95.0°C in the iCCD elution curve is calculated using the following test method. All individual values ​​and subranges greater than 90,000 g / mol are disclosed and included herein. For example, in the elution curve obtained via the improved comonomer composition distribution (iCCD) analysis method, the ethylene-alpha-olefin copolymer can have a molecular weight (Mw) greater than 95,000 g / mol or greater than 100,000 g / mol between 65.0°C and 95.0°C. For example, in the elution curve obtained via the improved comonomer composition distribution (iCCD) analysis method, the ethylene-α-olefin copolymer may have a molecular weight (Mw) of less than 250,000 g / mol between 65.0° C. and 95.0° C. In the elution curve obtained via the improved comonomer composition distribution (iCCD) analysis method, the ethylene-α-olefin copolymer may have a molecular weight (Mw) of 90,000 g / mol to 250,000 g / mol between 65.0° C. and 95.0° C. All individual values ​​and subranges between 90,000 g / mol and 250,000 g / mol are included and disclosed. For example, in an elution curve obtained via an improved comonomer composition distribution (iCCD) analysis method, the ethylene-α-olefin copolymer may have a molecular weight (Mw) of 95,000 to 200,000 g / mol; 100,000 to 150,000 g / mol; or 102,000 to 120,000 g / mol between 65.0°C and 95.0°C.

[0025] The ethylene-α-olefin copolymer may have a 3 Up to 0.940g / cm 3 All individual values ​​and subranges are included herein. For example, an ethylene-α-olefin copolymer may have a density of 0.912 g / cm 3 Up to 0.935g / cm 3 , 0.914g / cm 3 Up to 0.930g / cm 3 , 0.916g / cm 3 Up to 0.930g / cm 3 、0.910g / cm 3 Up to 0.920g / cm 3 , 0.920g / cm 3 Up to 0.930g / cm 3 , 0.916g / cm3 Up to 0.920g / cm 3 , 0.917g / cm 3 To 0.921g / cm 3 、0.918g / cm 3 Up to 0.922g / cm 3 , 0.924g / cm 3 Up to 0.928g / cm 3 or 0.925g / cm 3 Up to 0.929g / cm 3 density.

[0026] Based on ASTM D-1238, the ethylene-α-olefin copolymer may have a melt index (I2) of less than 6.0 g / 10 min, less than 5.0 g / 10 min, less than 4.0 g / 10 min, less than 3.0 g / 10 min, or less than 2.0 g / 10 min or less than 1.5 g / 10 min. In an embodiment, the melt index (I2) of the ethylene-α-olefin copolymer is less than 6.0 g / 10 min and greater than 0.5 g / 10 min, wherein the melt index (I2) is measured at 190 ° C and 2.16 kg load according to ASTM D 1238. The melt index (I2) of the ethylene-α-olefin copolymer may be 0.5 g / 10 min to 6.0 g / 10 min. The melt index (I2) of the ethylene-α-olefin copolymer may be 0.5 g / 10 min to 5.5 g / 10 min. The melt index (I2) of the ethylene-α-olefin copolymer may be 0.5 g / 10 min to 5.0 g / 10 min. The melt index (I2) of the ethylene-α-olefin copolymer may be 0.5 g / 10 min to 4.5 g / 10 min. The melt index (I2) of the ethylene-α-olefin copolymer may be 0.5 g / 10 min to 4.0 g / 10 min. The melt index (I2) of the ethylene-α-olefin copolymer may be 0.5 g / 10 min to 3.5 g / 10 min. The melt index (I2) of the ethylene-α-olefin copolymer may be 0.5 g / 10 min to 3.0 g / 10 min. The melt index (I2) of the ethylene-α-olefin copolymer may be 0.5 g / 10 min to 2.5 g / 10 min. The melt index (I2) of the ethylene-α-olefin copolymer may be 0.5 g / 10 min to 2.0 g / 10 min. The melt index (I2) of the ethylene-α-olefin copolymer may be 0.05 g / 10 min to 1.5 g / 10 min. The melt index (I2) of the ethylene-α-olefin copolymer may be 0.08 g / 10 min to 1.2 g / 10 min. The melt index (I2) of the ethylene-α-olefin copolymer may be 1.1 g / 10 min to 1.5 g / 10 min. The melt index (I2) of the ethylene-α-olefin copolymer may be 1.5 g / 10 min to 1.9 g / 10 min.

[0027] Commercially available examples of ethylene-α-olefin copolymers suitable for use in the present disclosure include, but are not limited to, those sold under the trade name DOWLEX TM and ELITE TM (such as DOWLEX TM) available from The Dow Chemical Company (Midland, MI), and copolymers available from Exxon Mobil under the trade name Exceed (such as Exceed 1018).

[0028] In addition to the ethylene-α-olefin copolymer, the biaxially oriented polyethylene film according to the embodiments disclosed herein may further comprise one or more additional polymers, such as propylene-based plastomers or elastomers, polyvinylidene chloride (PVDC), polyethylene terephthalate (PET), oriented polypropylene (OPP), polyacrylimide, butyl acrylate, peroxides (such as peroxidized polymers, for example, peroxidized olefins), silanes (e.g., epoxy silanes), reactive polystyrene, chlorinated polyethylene, olefin block copolymers, propylene copolymers, ionomers, and graft-modified polymers (e.g., maleic anhydride grafted polyethylene). The one or more additional polymers may be present in an amount less than or equal to 25 wt%, 20 wt%, 15 wt%, 12 wt%, 10 wt%, 8 wt%, 5 wt%, 3 wt%, 2 wt%, 1 wt%, or 0.5 wt%, based on the total weight of the biaxially oriented polyethylene film.

[0029] The biaxially oriented polyethylene film may include additional components, such as one or more additives. Such additives include, but are not limited to, antistatic agents, color enhancers, dyes, lubricants, opacifiers, nucleators, processing aids, pigments, primary antioxidants, secondary antioxidants, UV stabilizers, heat stabilizers, biocides, antimicrobial agents, colorants, antistatic agents, anti-caking agents, slip agents, tackifiers, flame retardants, clarifying agents / nucleators, odor reducers, antifungal agents, and combinations thereof. Based on the gross weight of the biaxially oriented polyethylene film including such additives, the biaxially oriented polyethylene film may include 0.1% to 10% of the combined weight of such additives.

[0030] polymerization

[0031] Any conventional polymerization process may be employed to produce the ethylene-α-olefin copolymers described herein. Such conventional polymerization processes include, but are not limited to, slurry polymerization processes, solution polymerization processes, gas phase polymerization processes using one or more conventional reactors such as loop reactors in parallel or in series, isothermal reactors, stirred tank reactors, batch reactors, and / or any combination thereof. Ethylene-α-olefin copolymers may be produced, for example, via a solution phase polymerization process using one or more loop reactors, isothermal reactors, and combinations thereof.

[0032] Typically, the solution phase polymerization process can be carried out at a temperature in the range of 115.0°C to 250.0°C (e.g., 115.0°C to 210.0°C) and at a pressure in the range of 300 psi to 1,000 psi (e.g., 400 psi to 800 psi) in one or more well-mixed reactors, such as one or more isothermal loop reactors or one or more adiabatic reactors. In a dual reactor, the temperature in the first reactor is in the range of 115.0°C to 190.0°C (e.g., 160.0°C to 180.0°C), while the second reactor temperature is in the range of 150.0°C to 250.0°C (e.g., 180.0°C to 220.0°C). In a single reactor, the temperature in the reactor is in the range of 115.0°C to 250.0°C (e.g., 115.0°C to 225.0°C).

[0033] The residence time in the solution phase polymerization process can be in the range of 2 to 30 minutes (e.g., 5 to 25 minutes). Ethylene, solvent, hydrogen, one or more catalyst systems, optionally one or more cocatalysts, and one or more comonomers are continuously fed to one or more reactors. Exemplary solvents include, but are not limited to, isoparaffins. For example, such solvents can be obtained under the trade name ISOPAR TM E is commercially available from ExxonMobil Chemical Co., Houston, Texas. The resulting mixture of the polyethylene composition and the solvent is then removed from the reactor and the polyethylene composition is separated. The solvent is typically recovered via a solvent recovery unit (i.e., a heat exchanger and a vapor liquid separator drum) and subsequently recycled back into the polymerization system.

[0034] Ethylene-α-olefin copolymers can be produced by solution polymerization in a dual reactor system, such as a dual loop reactor system, wherein ethylene is polymerized in the presence of one or more catalyst systems. One or more cocatalysts may be present. Ethylene-α-olefin copolymers can be produced by solution polymerization in a single reactor system, such as a single loop reactor system, wherein ethylene is polymerized in the presence of two catalyst systems.

[0035] Catalyst system

[0036] The term "independently selected" is used herein to refer to R groups (such as R 1 , R 2 , R 3 , R 4 and R 5 ) can be the same or different (e.g., R 1 , R 2 , R 3 , R 4 and R 5can be substituted alkyl, or R 1 and R 2 may be a substituted alkyl group and R 3 The use of the singular encompasses the use of the plural, and vice versa (e.g., a hexane solvent encompasses a plurality of hexanes). A named R group will generally have an art-recognized structure corresponding to the R group having that name. These definitions are intended to supplement and illustrate, but not to exclude, definitions known to those skilled in the art.

[0037] The term "procatalyst" refers to a compound that has catalytic activity when combined with an activator. The term "activator" refers to a compound that chemically reacts with the procatalyst in a manner that converts the procatalyst into a catalytically active catalyst. As used herein, the terms "cocatalyst" and "activator" are interchangeable terms.

[0038] When used to describe certain chemical groups containing carbon atoms, it has the form "(C x -C y )" means that the unsubstituted form of the chemical group has from x to y carbon atoms, including x and y. For example, (C1-C 40 ) Alkyl is an alkyl group having 1 to 40 carbon atoms in unsubstituted form. In some general structures, certain chemical groups may be substituted by one or more substituents such as R S Replace. Use the parenthetical term "(C x -C y )" defined by R S Substituted versions may contain more than y carbon atoms, depending on the number of any group R S For example, "is only one group R S Substituted (C1-C 40 ) alkyl (where R S is a phenyl group (-C6H5)") can contain from 7 to 46 carbon atoms. Therefore, in general, when the parenthetical term "(C x -C y )" is replaced by one or more substituents R containing carbon atoms. S When substituted, both x and y are added to the substituents R from all carbon atoms containing S The combined sum of the number of carbon atoms is used to determine the minimum and maximum total number of carbon atoms in a chemical group.

[0039] The term "substituted" means that at least one hydrogen atom (-H) bonded to a carbon atom or heteroatom of a corresponding unsubstituted compound or functional group is replaced by a substituent (e.g., R S) is replaced. The term "fully substituted" means that each hydrogen atom (H) bonded to a carbon atom or heteroatom of the corresponding unsubstituted compound or functional group is replaced by a substituent (e.g., R S The term "polysubstituted" means that at least two but less than all hydrogen atoms bonded to carbon atoms or heteroatoms of the corresponding unsubstituted compound or functional group are replaced by substituents.

[0040] The term "-H" means a hydrogen or a hydrogen radical covalently bonded to another atom. "Hydrogen" and "-H" are interchangeable and have the same meaning unless expressly specified otherwise.

[0041] Term "(C1-C 40 )alkyl" means a hydrocarbon group having 1 to 40 carbon atoms, and the term "(C1-C 40 )alkylene" means a hydrocarbon diradical having 1 to 40 carbon atoms, wherein each hydrocarbon radical and each hydrocarbon diradical is aromatic or non-aromatic, saturated or unsaturated, straight chain or branched, cyclic (including monocyclic and polycyclic, fused and non-fused polycyclic, including bicyclic; 3 or more carbon atoms) or acyclic, and is unsubstituted or replaced by one or more R S replace.

[0042] In the present disclosure, (C1-C 40 The hydrocarbon group may be unsubstituted or substituted (C1-C 40 )alkyl, (C3-C 40 )cycloalkyl, (C3-C 20 )cycloalkyl-(C1-C 20 ) alkylene, (C6-C 40 )aryl or (C6-C 20 )aryl-(C1-C 20 In some systems, the aforementioned (C1-C 40 ) Each of the alkyl groups has up to 20 carbon atoms (i.e., (C1-C 20 )hydrocarbyl), and in other systems, has a maximum of 12 carbon atoms.

[0043] Term "(C1-C 40 )alkyl" and"(C1-C 18 ) alkyl" means a saturated straight or branched hydrocarbon group having 1 to 40 carbon atoms or 1 to 18 carbon atoms, respectively, which hydrocarbon group is unsubstituted or substituted by one or more R S Substituted. Unsubstituted (C1-C 40 Examples of alkyl groups are unsubstituted (C1-C 20 ) alkyl; unsubstituted (C1-C 10)alkyl; unsubstituted (C1-C5)alkyl; methyl; ethyl; 1-propyl; 2-propyl; 1-butyl; 2-butyl; 2-methylpropyl; 1,1-dimethylethyl; 1-pentyl; 1-hexyl; 1-heptyl; 1-nonyl; and 1-decyl. Substituted (C1-C5)alkyl 40 Examples of alkyl groups are substituted (C1-C 20 ) alkyl, substituted (C1-C 10 ) alkyl, trifluoromethyl and [C 45 ] alkyl. The term "[C 45 ] alkyl" (with square brackets) means that there are up to 45 carbon atoms in the group (including substituents) and are, for example, substituted with one RS (C 27 -C 40 )alkyl, the RS is (C1-C5)alkyl. Each (C1-C5)alkyl may be methyl, trifluoromethyl, ethyl, 1-propyl, 1-methylethyl or 1,1-dimethylethyl.

[0044] The term "(C6-C 40 ) aryl" means an unsubstituted or substituted aryl having 6 to 40 carbon atoms (one or more R S )-substituted monocyclic, bicyclic or tricyclic aromatic hydrocarbon groups, at least 6 to 14 of the carbon atoms of the aromatic hydrocarbon group are aromatic ring carbon atoms, and the monocyclic, bicyclic or tricyclic groups include 1, 2 or 3 rings, respectively; wherein 1 ring is an aromatic ring, and 2 or 3 rings are independently condensed rings or non-condensed rings, and at least one of the 2 or 3 rings is an aromatic ring. Unsubstituted (C6-C 40 Examples of aryl groups are unsubstituted (C6-C 20 )aryl; unsubstituted (C6-C 18 )aryl; 2-(C1-C5)alkyl-phenyl; 2,4-bis(C1-C5)alkyl-phenyl; phenyl; fluorenyl; tetrahydrofluorenyl; dicyclopentadienylphenyl; hexahydrodicyclopentadienylphenyl; indenyl; dihydroindenyl; naphthyl; tetrahydronaphthyl; and phenanthrene. Substituted (C6-C 40 Examples of aryl groups are substituted (C1-C 20 ) aryl; substituted (C6-C 18 )aryl; 2,4-bis[(C 20 )alkyl]-phenyl; polyfluorophenyl; pentafluorophenyl; and fluoren-9-on-1-yl.

[0045] The term "(C3-C 40 )Cycloalkyl refers to a cycloalkyl having 3 to 40 carbon atoms which is unsubstituted or substituted with one or more R S Substituted saturated cyclic hydrocarbon groups. Other cycloalkyl groups (e.g., (C x -Cy )cycloalkyl) is defined in a similar manner as having x to y carbon atoms and being unsubstituted or substituted with one or more R S Substituted. Unsubstituted (C3-C 40 Examples of cycloalkyl groups are unsubstituted (C3-C 20 )cycloalkyl, unsubstituted (C3-C 10 )cycloalkyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl and cyclodecyl. 40 Examples of cycloalkyl groups are substituted (C3-C 20 )cycloalkyl, substituted (C3-C 10 )cycloalkyl, cyclopentanone-2-yl and 1-fluorocyclohexyl.

[0046] The term "(C1-C 40 ) Alkylene means an unsubstituted or substituted group having 1 to 40 carbon atoms. S Substituted saturated straight or branched chain divalent radical (i.e., the divalent radical is not on a ring atom). Unsubstituted (C1-C 50 Examples of alkylene groups are unsubstituted (C1-C 20 )alkylene, including unsubstituted -CH2CH2-, -(CH2)3-, -(CH2)4-, -(CH2)5-, -(CH2)6-, -(CH2)7-, -(CH2)8-, -CH2C*HCH3, and -(CH2)4C*(H)(CH3), wherein "C*" represents a carbon atom from which a hydrogen atom is removed to form a secondary or tertiary alkyl group. Substituted (C1-C 50 Examples of alkylene groups are substituted (C1-C 20 )alkylene, -CF2-, -C(O)- and -(CH2) 14 C(CH3)2(CH2)5- (i.e., 6,6-dimethyl-substituted n-1,20-eicosene). As mentioned previously, the two R S can be combined to form (C1-C 18 ) alkylene, substituted (C1-C 50 Examples of the alkylene group also include 1,2-bis(methylene)cyclopentane, 1,2-bis(methylene)cyclohexane, 2,3-bis(methylene)-7,7-dimethyl-bicyclo[2.2.1]heptane, and 2,3-bis(methylene)bicyclo[2.2.2]octane.

[0047] The term "(C3-C 40 ) Cycloalkylene means a cycloalkylene group having 3 to 40 carbon atoms which is unsubstituted or substituted with one or more R SSubstituted cyclic diradicals (ie, the diradical is on a ring atom).

[0048] The term "heteroatom" refers to an atom other than hydrogen or carbon. Examples of heteroatoms include O, S, S(O), S(O)2, Si(R C 2. P(R P )、N(R N )、-N=C(R C )2、-Ge(R C )2- or -Si(R C )-, where each R C , each R N and each R P is unsubstituted (C1-C 18 )alkyl or -H.

[0049] The term "heterohydrocarbon" refers to molecules or molecular backbones in which one or more carbon atoms are replaced by heteroatoms.

[0050] The term "(C1-C 40 )heteroalkyl" means a heteroalkyl group having 1 to 40 carbon atoms, and the term "(C1-C 40 The term "heteroalkylene" means a heteroalkyl diradical having from 1 to 40 carbon atoms, each of which has one or more heteroatoms. The radical of the heteroalkyl group is located on a carbon atom or a heteroatom, and the diradical of the heteroalkyl group can be located on: (1) one or two carbon atoms, (2) one or two heteroatoms, or (3) both carbon atoms and heteroatoms. Each (C1-C 50 ) heteroalkyl and (C1-C 50 ) The heteroalkylene group may be unsubstituted or (substituted by one or more R S ) substituted, aromatic or non-aromatic, saturated or unsaturated, linear or branched, cyclic (including mono- and polycyclic, fused and non-fused polycyclic) or acyclic.

[0051] (C1-C 40 ) heteroalkyl may be unsubstituted or substituted (C1-C 40 ) heteroalkyl, (C1-C 40 )alkyl-O-, (C1-C 40 )alkyl-S-, (C1-C 40 )alkyl-S(O)-, (C1-C 40 )alkyl-S(O)2-, (C1-C 40 )alkyl-Si(R C )2-、(C1-C 40 )alkyl-N(R N )-、(C1-C 40 )alkyl-P(R P)-、(C2-C 40 )heterocycloalkyl, (C2-C 19 )heterocycloalkyl-(C1-C 20 ) alkylene, (C3-C 20 )cycloalkyl-(C1-C 19 )heteroalkylene, (C2-C 19 )heterocycloalkyl-(C1-C 20 )heteroalkylene, (C1-C 40 )heteroaryl, (C1-C 19 )heteroaryl-(C1-C 20 ) alkylene, (C6-C 20 )aryl-(C1-C 19 )heteroalkylene or (C1-C 19 )heteroaryl-(C1-C 20 ) heteroalkylene.

[0052] The term "(C4-C 40 ") heteroaryl" means a monocyclic, bicyclic or tricyclic heteroaromatic hydrocarbon group having a total of 4 to 40 carbon atoms and a total of 1 to 10 heteroatoms, which is unsubstituted or substituted with (one or more RS), and the monocyclic, bicyclic or tricyclic group includes 1, 2 or 3 rings, respectively; wherein 2 or 3 rings are independently fused or non-fused, and at least one of the 2 or 3 rings is heteroaromatic. Other heteroaryl groups (e.g., typically (C x -C y ) heteroaryl, such as (C4-C 12 ) heteroaryl) is defined in a similar manner as having x to y carbon atoms (e.g. 4 to 12 carbon atoms) and being unsubstituted or substituted with one or more than one R Ssubstituted. The monocyclic heteroaromatic hydrocarbon group is a 5-membered or 6-membered ring. The 5-membered ring has 5 minus h carbon atoms, where h is the number of heteroatoms and can be 1, 2 or 3; and each heteroatom can be O, S, N or P. Examples of 5-membered heteroaromatic hydrocarbon groups are pyrrol-1-yl; piperidin-2-yl; furan-3-yl; thien-2-yl; pyrazol-1-yl; isoxazol-2-yl; isothiazol-5-yl; imidazol-2-yl; oxazol-4-yl; thiazol-2-yl; 1,2,4-triazol-1-yl; 1,3,4-oxadiazol-2-yl; 1,3,4-thiadiazol-2-yl; tetrazol-1-yl; tetrazol-2-yl; and tetrazol-5-yl. The 6-membered ring has 6 minus h carbon atoms, where h is the number of heteroatoms and can be 1 or 2, and the heteroatoms can be N or P. Examples of 6-membered ring heteroaromatic hydrocarbon groups are pyridin-2-yl; pyrimidin-2-yl; and pyrazin-2-yl. Bicyclic heteroaromatic hydrocarbon groups can be fused 5,6- or 6,6-ring systems. Examples of fused 5,6-ring system bicyclic heteroaromatic hydrocarbon groups are indol-1-yl; and benzimidazol-1-yl. Examples of fused 6,6-ring system bicyclic heteroaromatic hydrocarbon groups are quinolin-2-yl; and isoquinolin-1-yl. Bicyclic heteroaromatic hydrocarbon groups can be fused 5,6,5-ring systems; 5,6,6-ring systems; 6,5,6-ring systems; or 6,6,6-ring systems. Examples of fused 5,6,5-ring systems are 1,7-dihydropyrrolo[3,2-f]indol-1-yl. Examples of fused 5,6,6-ring systems are 1H-benzo[f]indol-1-yl. An example of a fused 6,5,6-ring system is 9H-carbazol-9-yl. An example of a fused 6,5,6-ring system is 9H-carbazol-9-yl. An example of a fused 6,6,6-ring system is acridin-9-yl.

[0053] The disclosed ethylene-α-olefin compositions can be produced by a variety of different catalyst systems. The following examples are intended to fully convey the scope of the present disclosure to those skilled in the art. The ethylene-α-olefin composition can be polymerized using a catalyst system comprising a metal-ligand complex of Structure I to form a first ethylene-based polymer; and in the presence of a catalyst system comprising a Ziegler / Natta catalyst, ethylene and a comonomer are polymerized to form a second ethylene-based polymer; and wherein Structure 1 is as follows:

[0054]

[0055] in:

[0056] M is titanium, zirconium or hafnium, each independently in a formal oxidation state of +2, +3 or +4; and n is an integer from 0 to 3, and wherein when n is 0, X is absent; and each X is independently a neutral, monoanionic or dianionic monodentate ligand; or two Xs taken together form a neutral, monoanionic or dianionic bidentate ligand; and X and n are selected in such a way that the metal-ligand complex of formula (I) is neutral overall; and each Z is independently O, S, N (C1-C 40 ) alkyl or P(C1-C 40 ) alkyl; and wherein the ZLZ fragment comprises formula (1):

[0057]

[0058] R 1 To R 16 are each independently selected from the group consisting of: substituted or unsubstituted (C1-C 40 )alkyl, substituted or unsubstituted (C1-C 40 ) heteroalkyl, Si(R C )3、Ge(R C )3. P(R P )2、N(R N )-2, OR C , SR C 、NO2、CN、CF3、R C S(O)-、R C S(O)2-、(R C )2C=N-、R C C(O)O-、R C OC(O)-、R C C(O)N(R)-、(R C )2NC(O)-, a halogen atom, a hydrogen atom; and wherein each R C are independently (C1-C30) hydrocarbon groups; R P is a (C1-C30) hydrocarbon group; and R N is a (C1-C30) hydrocarbon group; and wherein optionally two or more R groups (R 1 To R 16 ) may be combined together into one or more ring structures, such ring structures each independently having from 3 to 50 atoms in the ring excluding any hydrogen atoms. 9 To R 13 or R 4 To R 8 Two or more R groups in may be combined into one or more ring structures, wherein such ring structures each independently have from 3 to 50 atoms in the ring excluding any hydrogen atoms. 1 and R16 They can be shown as formula 2:

[0059]

[0060] Aryl, heteroaryl, alkyl, heteroalkyl, Si(R C )3、Ge(R C )3、P(RP)2、N(R N )-2, OR C , SR C , R C S(O)-、R C S(O)2-、(R C )2C=N-、R C C(O)O-、R C OC(O)-、R C C(O)N(R)-、(R C Each of )2NC(O)-, alkylene and heteroalkylene is independently unsubstituted or substituted with one or more R S Substituents; and each R S are independently halogen atoms, polyfluorinated, perfluorinated, unsubstituted (C1-C 18 )alkyl, F3C-, FCH2O-, F2HCO-, F3CO-, R3Si-, R3Ge-, RO-, RS-, RS(O)-, RS(O)2-, R2P-, R2N-, R2C=N-, NC-, RC(O)O-, ROC(O)-, RC(O)N(R)- or R2NC(O)-, or two R S Together they form an unsubstituted (C1-C 18 )alkylene, wherein each R is independently an unsubstituted (C1-C 18 )alkyl.

[0061] The catalyst for producing the ethylene / α-olefin interpolymer may be embodied as a catalyst system comprising bis((2-oxo-3-(dibenzo-1H-pyrrol-1-yl)-5-(methyl)phenyl)-2-phenoxymethyl)-methylene-1,2-cyclohexanediylhafnium(IV)dimethyl, represented by the following structure IA:

[0062]

[0063] Ziegler / Natta catalysts suitable for use in the present disclosure are typical supported Ziegler-type catalysts that are particularly useful at the high polymerization temperatures of the solution process. Examples of such compositions are compositions derived from organomagnesium compounds, alkyl halides or aluminum halides or hydrogen chloride and transition metal compounds. Examples of such catalysts are described in U.S. Pat. Nos. 4,612,300, 4,314,912, and 4,547,475, the teachings of which are incorporated herein by reference.

[0064] Particularly suitable organomagnesium compounds include, for example, hydrocarbon-soluble dihydrocarbylmagnesiums, such as dialkylmagnesiums and diarylmagnesiums. Exemplary suitable dialkylmagnesiums specifically include n-butyl-sec-butylmagnesium, diisopropylmagnesium, di-n-hexylmagnesium, isopropyl-n-butylmagnesium, ethyl-n-hexylmagnesium, ethyl-n-butylmagnesium, di-n-octylmagnesium, etc., wherein the alkyl group has 1 to 20 carbon atoms. Exemplary suitable diarylmagnesiums include diphenylmagnesium, dibenzylmagnesium and ditolylmagnesium. Suitable organomagnesium compounds include alkoxides and phenolates of alkylmagnesiums and arylmagnesiums and halides of arylmagnesiums and alkylmagnesiums, more preferably halogen-free organomagnesium compounds.

[0065] Halide sources include active non-metallic halides, metal halides and hydrogen chloride. Suitable non-metallic halides are represented by the formula R'X, wherein R' is hydrogen or an active monovalent organic group, and X is a halogen. Particularly suitable non-metallic halides include, for example, hydrogen halides and active organic halides, such as tertiary alkyl halides, allyl halides, benzyl halides and other active hydrocarbyl halides. By active organic halides is meant a hydrocarbyl halide containing an unstable halogen, the unstable halogen being at least as active as the halogen of sec-butyl chloride, i.e., easily lost to another compound, preferably as active as tert-butyl chloride. In addition to organic monohalides, it should be understood that organic dihalides, trihalides and other polyhalides having the activity defined above may also be suitably employed. Examples of preferred active non-metal halides include hydrogen chloride, hydrogen bromide, tert-butyl chloride, tert-amyl bromide, allyl chloride, benzyl chloride, butenyl chloride, methylvinylcarbinylchloride, α-phenylethyl bromide, benzhydryl chloride, etc. Most preferred are hydrogen chloride, tert-butyl chloride, allyl chloride and benzyl chloride.

[0066] Suitable metal halides include those represented by the formula MRy-aXa, wherein: M is a metal of Group IIB, Group IIIA or Group IVA in Mendeleev's periodic Table of Elements; R is a monovalent organic group; X is a halogen; the value of y corresponds to the valence of M; and the value of "a" is 1 to y. Preferred metal halides are of the formula AlR 3-a X aAluminum halides, wherein each R is independently a hydrocarbon group, such as an alkyl group; X is a halogen; and "a" is a number from 1 to 3. Most preferred are alkylaluminum halides, such as ethylaluminum sesquichloride, diethylaluminum chloride, ethylaluminum dichloride, and diethylaluminum bromide, with ethylaluminum dichloride being particularly preferred. Alternatively, a metal halide, such as aluminum trichloride or a combination of aluminum trichloride and an alkylaluminum halide or a trialkylaluminum compound may be suitably employed.

[0067] Any of the conventional Ziegler-Natta transition metal compounds can be usefully used as the transition metal component in preparing the supported catalyst component. Typically, the transition metal component is a compound of a Group IVB, Group VB, or Group VIB metal. The transition metal component is typically represented by the formula: TrX′ 4-q (OR1)q、TrX′ 4-q (R2)q, VOX′3 and VO(OR)3.

[0068] Tr is a Group IVB, Group VB or Group VIB metal, preferably a Group IVB or Group VB metal, preferably titanium, vanadium or zirconium; q is 0 or a number equal to or less than 4; X′ is a halogen, and R1 is an alkyl group, an aryl group or a cycloalkyl group having 1 to 20 carbon atoms; and R2 is an alkyl group, an aryl group, an aralkyl group, a substituted aralkyl group, etc.

[0069] Aryl, aralkyl and substituted aralkyl contain 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms. When the transition metal compound contains a hydrocarbyl R2, the hydrocarbyl is an alkyl, cycloalkyl, aryl or aralkyl group, and the hydrocarbyl group will preferably not contain an H atom in the position β to the metal carbon bond. Illustrative but non-limiting examples of aralkyl groups are methyl, neopentyl, 2,2-dimethylbutyl, 2,2-dimethylhexyl; aryl groups such as benzyl; cycloalkyl groups such as 1-norbornyl. If desired, mixtures of these transition metal compounds can be used.

[0070] Illustrative examples of transition metal compounds include TiCl4, TiBr4, Ti(OC2H5)3Cl, Ti(OC2H5)Cl3, Ti(OC4H9)3Cl, Ti(OC3H7)2Cl2, Ti(OC6H 13 )2Cl2、Ti(OC8H 17 )2Br2 and Ti(OC 12 H 25)Cl3, Ti(O-iC3H7)4, and Ti(O-nC4H9)4. Illustrative examples of vanadium compounds include VCl4, VOCl3, VO(OC2H5)3, and VO(OC4H9)3. Illustrative examples of zirconium compounds include ZrCl4, ZrCl3(OC2H5), ZrCl2(OC2H5)2, ZrCl(OC2H5)3, Zr(OC2H5)4, ZrCl3(OC4H9), ZrCl2(OC4H9)2, and ZrCl(OC4H9)3.

[0071] Inorganic oxide supports can be used in the preparation of the catalyst, and the support can be any particulate oxide or mixed oxide that has been thermally or chemically dehydrated so that it is substantially free of adsorbed moisture. See U.S. Pat. Nos. 4,612,300; 4,314,912; and 4,547,475; the teachings of which are incorporated herein by reference.

[0072] The catalyst system described above can be rendered catalytically active by contacting it with an activating cocatalyst, or by combining it with an activating cocatalyst, or by using an activation technique, such as an activation technique known in the art for metal-based olefin polymerization reactions. Activating cocatalysts suitable for use herein include alkylaluminums; polymeric or oligomeric aluminoxanes (also known as aluminoxanes); neutral Lewis acids; and non-polymeric, non-coordinating, ion-forming compounds (including the use of such compounds under oxidizing conditions). A suitable activation technique is bulk electrolysis. Combinations of one or more of the foregoing activating cocatalysts and techniques are also contemplated. The term "alkylaluminum" means a monoalkylaluminum dihydride or monoalkylaluminum dihalide, a dialkylaluminum hydride or dialkylaluminum halide, or a trialkylaluminum. Aluminoxanes and their preparation are known, for example, in U.S. Pat. No. 6,103,657. Examples of preferred polymeric or oligomeric aluminoxanes are methylaluminoxane, triisobutylaluminum-modified methylaluminoxane, and isobutylaluminoxane.

[0073] Exemplary Lewis acid activating cocatalysts are Group 13 metal compounds containing 1 to 3 hydrocarbyl substituents as described herein. Exemplary Group 13 metal compounds are tri(hydrocarbyl) substituted aluminum compounds or tri(hydrocarbyl)-boron compounds. Exemplary Group 13 metal compounds also include tri(hydrocarbyl) substituted aluminum or tri(hydrocarbyl)-boron compounds, which are tri((C1-C 10 )alkyl)aluminum or tri((C6-C 18 ) aryl) boron compounds and halogenated (including perhalogenated) derivatives thereof. Exemplary Group 13 metal compounds are tri(fluoro-substituted phenyl) borane or tri(pentafluorophenyl) borane. The activating cocatalyst may be tri((C1-C 20 ) alkyl borate (e.g. trityl tetrafluoroborate) or tris((C1-C 20)alkyl)tetra((C1-C 20 As used herein, the term "ammonium" refers to a nitrogen cation that is ((C1-C 20 )alkyl)4N + 、((C1-C 20 )alkyl)3N(H) + 、((C1-C 20 )alkyl)2N(H)2 + 、(C1-C 20 )Hydrocarbon N(H)3 + or N(H)4 + , where (C1-C 20 ) The hydrocarbon groups may be the same or different.

[0074] Exemplary combinations of neutral Lewis acid activating cocatalysts include those comprising tri((C1-C4)alkyl)aluminum and tri((C6-C 18 )aryl)boron compounds, especially tris(pentafluorophenyl)borane. Other examples are combinations of such neutral Lewis acid mixtures with polymeric or oligomeric aluminoxanes, and combinations of a single neutral Lewis acid, especially tris(pentafluorophenyl)borane, with polymeric or oligomeric aluminoxanes. Exemplary molar ratios of (metal-ligand complex):(tris(pentafluorophenylborane):(aluminoxane) [e.g., (Group 4 metal-ligand complex):(tris(pentafluorophenylborane):(aluminoxane)] are 1:1:1 to 1:10:30, or 1:1:1.5 to 1:5:10.

[0075] Many activating cocatalysts and activation techniques have been previously taught in the following U.S. patents for different metal-ligand complexes: U.S. Pat. Nos. 5,064,802, 5,153,157, 5,296,433, 5,321,106, 5,350,723, 5,425,872, 5,625,087, 5,721,185, 5,783,512, 5,883,204, 5,919,983, 6,696,379, and 7,163,907. Examples of suitable hydrocarbyl oxides are disclosed in U.S. Pat. No. 5,296,433. Examples of Bronsted acid salts suitable for use as addition polymerization catalysts are disclosed in US 5,064,802, US 5,919,983, and US 5,783,512. Examples of suitable salts of cationic oxidants and non-coordinating compatible anions as activating cocatalysts for addition polymerization catalysts are disclosed in US 5,321,106. Examples of carbon ion salts suitable for use as activating cocatalysts for addition polymerization catalysts are disclosed in US 5,350,723. Examples of silyl salts suitable for use as activating cocatalysts for addition polymerization catalysts are disclosed in US 5,625,087. Examples of suitable complexes of alcohols, thiols, silanols, and oximes with tris(pentafluorophenyl)borane are disclosed in US 5,296,433. Some of these catalysts are also described in a portion of US 6,515,155 Bl starting at column 50, line 39 through column 56, line 55, only the portion described therein being incorporated herein by reference.

[0076] The catalyst system described above can be activated to form an active catalyst composition by combining with one or more cocatalysts (such as cation-forming cocatalysts, strong Lewis acids, or combinations thereof). Suitable cocatalysts include polymeric or oligomeric aluminoxanes, especially methylaluminoxane, and inert compatible non-coordinating ion-forming compounds. Exemplary suitable cocatalysts include, but are not limited to, modified methylaluminoxane (MMAO), bis(hydrogenated tallow alkyl)methyl, tetrakis(pentafluorophenyl)borate (1-)amine, triethylaluminum (TEA), and any combination thereof.

[0077] One or more of the aforementioned activating cocatalysts may be used in combination with one another. A combination of a mixture of tri((C1-C4)hydrocarbyl)aluminum, tri((C1-C4)hydrocarbyl)borane or ammonium borate and an oligomeric or polymeric aluminoxane compound may be used.

[0078] filler

[0079] The biaxially oriented polyethylene film may comprise from 40% to 75% by weight of filler, based on the gross weight of the film. All individual values ​​of from 40% to 75% by weight of filler are also disclosed and incorporated herein. For example, the biaxially oriented polyethylene film may comprise from 40% to 75% by weight, from 45% to 70% by weight, from 45% to 75% by weight, from 68% to 72% by weight, from 58% to 62% by weight, from 48% to 52% by weight, from 50% to 70% by weight, from 50% to 60% by weight, or from 60% to 70% by weight of filler, based on the gross weight of the biaxially oriented polyethylene film.

[0080] The filler used in the biaxially oriented polyethylene film can be, but is not limited to, calcium carbonate, magnesium carbonate, barium sulfate, magnesium sulfate, aluminum sulfate, magnesium oxide, aluminum oxide, mica, talc, silica, clay, glass spheres, titanium dioxide, aluminum hydroxide, zeolite, or a combination thereof. For example, the filler can be calcium carbonate. In an embodiment, the filler includes calcium carbonate.

[0081] Biaxially oriented polyethylene films, laminates and articles

[0082] The biaxially oriented polyethylene film can have a relative humidity of greater than 300 g / m 2 The water vapor transmission rate (WVTR) of the biaxially oriented polyethylene film at 40.0°C and 60% relative humidity may be greater than 400 g / m 2 The biaxially oriented polyethylene film may have a water vapor transmission rate (WVTR) of greater than 800 g / m at 40.0°C and 60% relative humidity. 2 The biaxially oriented polyethylene film may have a water vapor transmission rate (WVTR) of greater than 1000 g / m at 40.0°C and 60% relative humidity. 2 The biaxially oriented polyethylene film may have a water vapor transmission rate (WVTR) of greater than 2000 g / m at 40.0°C and 60% relative humidity. 2 / day water vapor transmission rate (WVTR). The biaxially oriented polyethylene film can have a water vapor transmission rate of 300 g / m at 40.0°C and 60% relative humidity. 2 / day to 3000g / m 2 Water Vapor Transmission Rate (WVTR) / day. All individual values ​​and subranges from 300 to 3000 are disclosed and included herein. For example, a biaxially oriented polyethylene film may have a water vapor transmission rate of 400 g / m at 40.0°C and 60% relative humidity. 2 / day to 2500g / m 2 / day or 1,000g / m 2 / day to 2500g / m 2Water vapor transmission rate (WVTR) of 100% / day. The biaxially oriented polyethylene film can have an elongation at break of less than 200% in both the longitudinal and transverse directions, wherein the elongation can be measured according to the following test method. The biaxially oriented polyethylene film can have an elongation at break of less than 100% in both the longitudinal and transverse directions, wherein the elongation can be measured according to the following test method. The biaxially oriented polyethylene film can have an elongation at break of less than 60% in both the longitudinal and transverse directions, wherein the elongation can be measured according to the following test method. The biaxially oriented polyethylene film can have an elongation at break of 60% to 200% in both the longitudinal and transverse directions, wherein the elongation can be measured according to the following test method. All individual values ​​from 60% to 200% are included and disclosed. For example, the biaxially oriented polyethylene film can have an elongation at break of 60% to 100% in both the longitudinal and transverse directions, wherein the elongation can be measured according to the following test method.

[0083] The basis weight of the biaxially oriented polyethylene film is not particularly limited, but can be 3gsm to 65gsm. The basis weight of the biaxially oriented polyethylene film can depend on several factors, including the desired properties of the film, the end-use application of the film, the equipment that can be used to make the film, the cost allowed by the application, and other factors. All individual values ​​and subranges of 3gsm to 65gsm are included and disclosed herein. For example, the biaxially oriented polyethylene film can have a basis weight of 5gsm to 60gsm, 10gsm to 50gsm, 15gsm to 40gsm, 15gsm to 35gsm, 15gsm to 30gsm, 15gsm to 20gsm, or 20gsm to 25gsm.

[0084] When measured using the following procedure, the film may have a transverse tensile strength greater than 0.3N / in / gsm. When measured using the following procedure, the film may have a transverse tensile strength greater than 0.4N / in / gsm. When measured using the following procedure, the film may have a transverse tensile strength greater than 0.5N / in / gsm. When measured using the following procedure, the film may have a transverse tensile strength greater than 0.6N / in / gsm. When measured using the following procedure, the film may have a transverse tensile strength greater than 0.8N / in / gsm. When measured using the following procedure, the film may have a transverse tensile strength greater than 1.5N / in / gsm. When measured using the following procedure, the film may have a transverse tensile strength of 0.3N / in / gsm to 1.8N / in / gsm. All individual values ​​of 0.3N / in / gsm to 1.8N / in / gsm are included and disclosed. For example, the film can have a transverse tensile strength of 0.4 N / in / gsm to 1.7 N / in / gsm when measured using the procedure described below.

[0085] When measured using the following procedure, the film may have a longitudinal tensile strength greater than 0.3N / in / gsm. When measured using the following procedure, the film may have a longitudinal tensile strength greater than 0.4N / in / gsm. When measured using the following procedure, the film may have a longitudinal tensile strength greater than 0.8N / in / gsm. When measured using the following procedure, the film may have a longitudinal tensile strength greater than 1.0N / in / gsm. When measured using the following procedure, the film may have a longitudinal tensile strength greater than 1.5N / in / gsm. When measured using the following procedure, the film may have a longitudinal tensile strength of 0.3N / in / gsm to 1.8N / in / gsm. All individual values ​​and subranges of 0.3N / in / gsm to 1.8N / in / gsm are included and disclosed. For example, when measured using the following procedure, the film may have a longitudinal tensile strength of 0.4N / in / gsm to 1.7N / in / gsm.

[0086] The biaxially oriented polyethylene film can be prepared by methods known to those skilled in the art. The biaxially oriented film can be prepared by a double bubble process. The biaxially oriented film can be a tenter biaxially oriented polyethylene film.

[0087] The disclosed biaxially oriented polyethylene film can be incorporated into a laminate such as a film / nonwoven laminate. The typical nonwoven fabric for this type of laminate can be a spun web, an air-laid web, a carded web or their composite material. Typical nonwoven composite materials for laminates with breathable films of the present disclosure include three beams of spunbond (e.g., S / S / S), spunbond / meltblown / spunbond composite materials (e.g., S / M / S) etc. The common method for bonding film to nonwoven fabrics includes, for example, bonding hot melt adhesive lamination, ultrasonic bonding and the thermal bonding achieved by calender or nip roll.

[0088] The disclosed film can be biaxially oriented using a tenter sequential biaxial orientation process or a double bubble orientation process. Typically, a tenter sequential biaxial orientation process is used, with the tenter incorporated as part of the extrusion line. After extrusion from the flat die, the film is cooled on a cooling roll and immersed in a water bath. The cast film is then transferred to a series of rollers with different rotation speeds to achieve stretching in the longitudinal direction. There are several pairs of rollers in the MD stretching section of the production line, and the several pairs of rollers are oil heated. Pairs of rollers are used sequentially as preheating rollers, stretching rollers, and rollers for relaxation and annealing. The temperature of each pair of rollers is controlled separately. After longitudinal stretching, the film web is transferred to a tenter hot air oven with heating zones for transverse stretching. The first several zones are used for preheating, the subsequent zones are used for stretching, and then the final zone is used for annealing.

[0089] Typically, in the double bubble orientation process, a thick wall tube is extruded using a circular die. The tube is simultaneously inflated, pulled down, and deflated. Inflation orients the film in the transverse direction, while the downward pull and deflation orient the film in the machine direction. Since similar machine and transverse orientation is achieved, a balanced film is produced.

[0090] The biaxially oriented polyethylene film can be oriented in the machine direction at a stretch ratio of 2:1 to 9:1, 3:1 to 9:1, 2:1 to 6:1, 5:1 to 6:1, 5:5 to 6:6, or any ratio therebetween, and in the transverse direction at a stretch ratio of 2:1 to 9:1, 3:1 to 9:1, 2:1 to 6:1, 5:1 to 6:1, 5:5 to 6:6, or any ratio therebetween.

[0091] The biaxially oriented polyethylene film disclosed in the present invention can be incorporated into various articles, such as diapers, training pants, feminine hygiene products, adult incontinence products, medical drapes, medical gowns, surgical gowns, etc. The biaxially oriented polyethylene film can be referred to as a breathable film. In articles such as diapers, training pants, feminine hygiene products, and adult incontinence products, breathable biaxially oriented polyethylene films are also often referred to as backsheets. In medical products, breathable films are often referred to as "barrier layers" because breathable films can prevent contamination of patients by health care workers, and vice versa. Breathable films can be incorporated into such articles using techniques known to those skilled in the art based on the teachings herein.

[0092] Test Method

[0093] density

[0094] Density is measured according to ASTM D792 and is expressed in grams / cm 3 (g / cm 3 )express.

[0095] Melt index (I2)

[0096] Melt index (I2) is measured according to ASTM D-1238 at 190°C and 2.16 kg. Values ​​are reported in g / 10 min, which corresponds to grams eluted per 10 min.

[0097] Basis Weight

[0098] Cut the sample into 100 cm 2 The sample is weighed on a balance. The weight is then multiplied by 100 to convert the measurement to grams per square meter (gsm).

[0099] Water Vapor Transmission Rate (WVTR)

[0100] Water vapor transmission rate (WVTR) is measured based on the standard cup method of ASTM E96-16 and GB / T 12704.2 (2009). 10 ml of distilled water is filled into the test dish. The specimen is attached to the test dish and the dish is sealed with a gasket and a ring cap. The weight of the dish assembly is recorded as the mass (Wa). The dish assembly is placed in a control room with constant temperature (40.0°C) and humidity (60%). After four (4) hours, the dish assembly is removed from the control room and weighed, where the mass is recorded as (Wb). WVTR is calculated by the following equation:

[0101]

[0102] WVTR: Water vapor transmission rate, [g / m 2 *sky]

[0103] Wa: The mass of the test dish assembly before testing, [g]

[0104] Wb: The mass of the test dish assembly after testing, [g]

[0105] S: Test area = 0.0032m 2 ,[m 2 ]

[0106] T: test time = 4 hours, [h]

[0107] Tensile strength and elongation at break

[0108] The longitudinal and transverse tensile strength and elongation at break of the film were measured according to ASTM D882. The measurement was performed using an Instron 5965. The sample was cut into 25.4 mm*50 mm pieces by a flat clamping jar. The test speed was 500 mm / min. The tensile strength and elongation at break were measured by stretching a 1 inch wide film while recording the load until the film broke.

[0109] Hydrostatic Head

[0110] The hydrostatic head was measured in a hydrostatic head tester model M018 from SDLATLAS according to ISO 811. A circular 100 cm 2 Breathe sample. Pressure is gradually increased at a rate of 60 cm H2O / min. The water pressure required to cause 3 or more failure locations is recorded. Results are reported as water column height (cm). Higher values ​​indicate better penetration resistance.

[0111] Improved Comonomer Composition Distribution (iCCD)

[0112] An improved method for comonomer content analysis (iCCD) was developed in 2015 (Cong and Parrott et al., WO2017040127A1). iCCD testing was performed using a crystallization elution fractionation instrument (CEF) (PolymerChar, Spain) equipped with an IR-5 detector (PolymerChar, Spain) and a two-angle light scattering 2040 detector (Precision Detectors, now Agilent Technologies). Ortho-dichlorobenzene (ODCB, 99% anhydrous or technical grade) was used. Silica gel 40 (particle size 0.2 mm to 0.5 mm, catalog number 10181-3) was obtained from EMD Chemicals and used to fill the column to dry 1,2-dichlorobenzene (ODCB) solvent. The ODCB solvent drying column was installed at the inlet of the solvent delivery system (pump). The CEF instrument was equipped with an autosampler with N2 sweep function. ODCB was purged with dry nitrogen (N2) for one hour before use. Sample preparation was performed with an autosampler at 4 mg / ml (unless otherwise specified) at 160.0°C for 1 hour with shaking. The injection volume was 300 μl. The temperature profile of the iCCD was: crystallization from 105.0°C to 30.0°C at 3.0°C / min, thermal equilibrium at 30.0°C for 2 minutes (including the soluble fraction elution time set to 2 minutes), elution from 30.0°C to 140.0°C at 3.0°C / min. The flow rate during crystallization was 0.0 ml / min. The flow rate during elution was 0.50 ml / min. Data were collected at one data point per second.

[0113] The iCCD column was filled with gold-plated nickel particles (Bright7GNM8-NiS, Nippon Chemical Industrial Co.) in a stainless steel tube of 15 cm (length) X 1 / 4" (ID). The column was filled and conditioned according to references (Cong, R.; Parrott, A.; Hollis, C.; Cheatham, M. WO2017040127A1). The final pressure of 1,2,4-trichlorobenzene (TCB) slurry filling was 150 bar.

[0114] The column temperature was calibrated by using a reference material linear homopolymer polyethylene (with zero comonomer content, melt index (I2) of 1.0, polydispersity Mw / Mn of approximately 2.6 by conventional gel permeation chromatography, 1.0 mg / ml) and a mixture of eicosane (2 mg / ml) in 1,2-dichlorobenzene (ODCB). The iCCD temperature calibration consisted of four steps: (1) calculation of the delay volume, which was defined as the temperature offset between the measured peak elution temperature of eicosane minus 30.00 °C; (2) subtraction of the temperature offset of the elution temperature from the iCCD raw temperature data. It should be noted that this temperature bias is a function of experimental conditions, such as elution temperature, elution flow rate, etc.; (3) Create a linear calibration line that converts elution temperature in the range of 30.00°C and 140.00°C, so that the linear homopolymer polyethylene reference has a peak temperature at 101.0°C and eicosane has a peak temperature at 30.0°C; (4) For the soluble fraction measured isothermally at 30.0°C, according to reference (Cerk and Cong et al., US9,688,795), the elution temperature below 30.0°C is linearly extrapolated by using an elution heating rate of 3.0°C / min.

[0115] The relationship between comonomer content and elution temperature of iCCD was constructed by using 12 reference materials (ethylene homopolymers and ethylene-octene random copolymers made with single-site metallocene catalysts with ethylene equivalent weight average molecular weights ranging from 35,000 to 128,000. Cong et al., Macromolecules 2011, 44, 3062). The octene content of the reference materials was analyzed by 13C NMR. All of these reference materials were analyzed at 4 mg / mL in the same manner as previously specified. The elution peak temperatures reported are shown in Figure 2 .

[0116] The molecular weight of the polymer and the molecular weight of the polymer fractions were determined directly from the LS detector (90 degree angle) and the concentration detector (IR-5) by assuming a shape factor of 1 and all virial coefficients equal to zero according to the Rayleigh-Gans-Debys approximation (Striegel and Yau, Modern Size Exclusion Liquid Chromatogram, pp. 242 and 263). The baselines were subtracted from the LS and concentration detector chromatograms. The integration window was set to integrate the entire chromatogram over the elution temperature (temperature calibration specified above) range of 23.0°C to 120.0°C.

[0117] The weight % of copolymer eluting between 65.0°C and 95.0°C in the iCCD was calculated as the integrated area of ​​the iCCD elution curve between 65.0°C and 95.0°C minus baseline divided by the total integrated area of ​​the iCCD minus baseline, times 100%.

[0118] Calculation of molecular weight (Mw) from iCCD involves the following steps:

[0119] (1) Measure the inter-detector offset: This offset is defined as the geometric volume offset between the LS detector and the concentration detector. It is calculated as the difference in elution volume (mL) of the polymer peak between the concentration detector and the LS chromatogram. This is converted to a temperature offset by using the elution heat rate and the elution flow rate. A linear high-density polyethylene (comonomer content zero, melt index (I2) of 1.0, polydispersity M by conventional gel permeation chromatography) was used. w / M n The same experimental conditions as the normal iCCD method described above were used, except for the following parameters: crystallization from 140.0°C to 137.0°C at 10.0°C / min, thermal equilibrium at 137.0°C for 1 minute as the soluble fraction elution time, soluble fraction (SF) time of 7 minutes, elution from 137.0°C to 142.0°C at 3.0°C / min. The flow rate during crystallization was 0.0 ml / min. The flow rate during elution was 0.80 ml / min. The sample concentration was 1.0 mg / ml.

[0120] (2) Prior to integration, each LS data point in the LS chromatogram was shifted to correct for inter-detector offset.

[0121] (3) Subtract the baseline and integrate the LS and concentration chromatograms over the entire elution temperature range of step (1). The MW detector constant is calculated by using a known MW HDPE sample (I2 of 1.0, Mw / Mn ~ 2.6) and the area ratio of the LS and concentration integrated signals.

[0122] (4) The molecular weight of the polymer was calculated by using the ratio of the integrated light scattering detector (90 degree angle) to the concentration detector and using the MW detector constant. Using the measured MW detector constant, NIST NBS 1475a analyzed using the same method as specified in (1) above gave a molecular weight of 58,000.

[0123] The molecular weight (Mw) of the copolymer eluting between 65.0°C and 95.0°C in the iCCD was calculated by dividing the total integrated area of ​​the light scattering detector results by the total area of ​​the IR-5 concentration detector results and the IR-5 concentration detector constant.

[0124] Triple Detector Gel Permeation Chromatography (GPC)

[0125] The composition of polymer resins and blends was tested using PolymerChar GPC-IR high temperature GPC. The GPC system consisted of a 150.0°C high temperature chromatograph equipped with an infrared detector, a light scattering detector, and a viscometer. Four PL mixed A columns were installed in series before the IR-5 detector in the detector oven. 1,2,4-Trichlorobenzene was used as the liquid phase. The GPC was calibrated using a series of narrow molecular weight (Mw) polystyrene standards. The Mw of the polystyrene standards ranged from 580 g / mol to 9,835,000 g / mol. A fifth-order polynomial was used to fit the corresponding polystyrene calibration points. The polystyrene standard peak molecular weight was converted to polyethylene molecular weight using a conversion factor of 0.43. Sample preparation was performed with an automatic sampler at 2 mg / mL at 160.0°C for 3 hours. The injection volume was 200 ml. The temperature of the GPC was 150.0°C, and the flow rate was 1 mL / min.

[0126] NMR

[0127] The sample was dissolved in TCE-d2 at 120.0°C for 6 hours to obtain a homogeneous solution. 13 All NMR data were acquired on a Bruker AVANCE II 400 MHz spectrometer operating at the C resonance frequency. A 10 mm BBO probe was used. Chemical shifts are given in ppm (parts per million) relative to TCE-d2. Zgig was used as the pulse program for the C NMR, and the observation pulse was 90 degrees. The recycle delay was set to 6 seconds. (See Cong et al., Macromolecules 2011) Monomer weight % has an error limit of + / - 0.3%.

[0128] Example

[0129] The following examples are provided to further illustrate the present disclosure in detail but should not be construed as limiting the scope of the claims.

[0130] The raw materials used in the examples of the present invention (Inv.Ex.) and comparative examples (Comp.Ex.) are explained in Table 1 as follows:

[0131] Table 1 Raw materials

[0132]

[0133]

[0134] Experimental and comparative films were produced using a twin screw extrusion compounding line. The compounding formula for the comparative examples and the examples of the present invention was about 30 to 50 wt% of a polymer (e.g., ethylene-α-olefin copolymer), 50 to 70 wt% of CaCO3, and 2000 ppm of IRGANOX B900. The composition was extruded using a Coperion ZSK 40McPlus twin screw extruder at a screw speed of 250 rpm, with barrel 1 at 120.0°C, barrels 2-15 at 180.0°C, and a die at 180.0°C. The output was 40 kg / h, with 100% CaCO3 side feed.

[0135] After compounding, 400um single layer cast sheets were prepared on a Davis-Standard casting line using 3 single screw extruders. The screw diameter was 32mm and the L / D was 30:1. Zone 1 was set to 210.0°C, Zone 2 was set to 230.0°C, Zone 3 was set to 250.0°C, and Zone 4 was set to 250.0°C. A T-die with a die width of 500mm and a die gap of 1mm was used. The output was set to 20kg / h. The resulting sheet was biaxially oriented on a Brückner Karo IV laboratory stretcher. The structure of the resulting film is listed in Table 2 below.

[0136] Table 2 Structures of the membranes of the present invention and comparative membranes

[0137]

[0138]

[0139] Comparative Example 1 was prepared by a cast MDO process. The compounded composition was extruded using a Dr. Collin casting line with one 30 mm extruder and three 25 mm extruders to produce the samples. All extruders ran the same composition so that the films produced in each case were conceptually equivalent to monolayer films. Zone 1 was set to 190.0°C, Zone 2 was set to 210.0°C, Zone 3 was set to 220.0°C, and Zones 4 to 6 were set to 230°.0C. After extrusion, the film was reheated, stretched, annealed, cooled and wound onto a roll. The sample film was oriented in the longitudinal direction with a stretch ratio of 5:1 under the following processing conditions.

[0140] Table 3: Longitudinal orientation processing parameters

[0141]

[0142] 400um single layer cast sheets were stretched at different temperatures and stretch ratios (5×5, 6×6). The biaxial stretching results are summarized in Table 4. Sheets that can be biaxially stretched without rupture or holes are marked as Y. If after stretching, the resulting film is ruptured or has holes, it is marked as N.

[0143] Table 4 Resin properties and biaxial stretching results

[0144]

[0145]

[0146] According to the test method described above, the film of the present invention and the comparative film were tested. The test results are shown in the following Table 5:

[0147] Table 5 Film Characteristics

[0148]

[0149]

[0150] As can be seen above, all of the inventive samples show higher transverse direction (TD) tensile strength even at lower basis weights than the comparative examples. In the inventive examples, a tensile strength of at least 0.43 N / inch / gsm is achieved even at 70 wt% CaCO loading. In a typical breathable backsheet, the CaCO loading is less than 55 wt% to maintain TD tensile strength.

Claims

1. A biaxially oriented polyethylene film, comprising: a. 25 wt% to 60 wt% of an ethylene-α-olefin copolymer, the ethylene-α-olefin copolymer comprising i) ethylene monomer and 1-octene or 1-hexene comonomer, ii) at least 50 wt% of the copolymer amount eluted between 65.0°C and 95.0°C in an elution curve obtained via an improved comonomer composition distribution (iCCD) analysis method, and iii) a molecular weight (Mw) greater than 90,000 g / mol between 65.0°C and 95.0°C in the elution curve obtained via an improved comonomer composition distribution (iCCD) analysis method; and b. 40% to 70% by weight of filler; And wherein the film has a relative humidity of greater than 300 g / m 2 / day water vapor transmission rate, and has a breaking elongation of less than 200% in the longitudinal and transverse directions.

2. The membrane according to any one of the preceding claims, wherein the ethylene-α-olefin copolymer has a molecular weight (Mw) of less than 250,000 g / mol between 65.0°C and 95.0°C in the elution curve obtained via an improved comonomer composition distribution (iCCD) analysis method.

3. The film of any one of the preceding claims, wherein the film is a tenter frame biaxially oriented polyethylene film.

4. The film of any one of the preceding claims, wherein the filler comprises calcium carbonate.

5. The film of any one of the preceding claims, wherein the film has a transverse tensile strength greater than 0.3 N / in / gsm.

6. The film of any preceding claim, wherein the film has transverse and longitudinal tensile strengths greater than 0.3 N / in / gsm.

7. The membrane according to any one of the preceding claims, wherein the membrane is produced by a double bubble process.

8. The film according to any one of the preceding claims, wherein the melt index (I2) of the ethylene-α-olefin copolymer is less than 6.0 g / 10 min and greater than 0.5 g / 10 min, wherein the melt index (I2) is measured according to ASTM D 1238 at 190°C and 2.16 kg load.

9. The film according to any one of the preceding claims, wherein the ethylene / α-olefin copolymer has a density of 0.910 g / cm 3 Up to 0.940g / cm 3 .

10. The film according to any one of the preceding claims, wherein the ethylene-α-olefin copolymer comprises 80 to 97 wt% ethylene monomer and 3 to 20 wt% 1-octene or 1-hexene comonomer, based on the total weight of the ethylene-α-olefin copolymer.

11. The film of any preceding claim, wherein the film has a basis weight of from 5 gsm to 60 gsm.

12. The film of any one of the preceding claims, wherein the film is oriented in the machine direction at a stretch ratio of 3:1 to 9:1 and in the transverse direction at a stretch ratio of 3:1 to 9:

1.

13. An article comprising: a biaxially oriented polyethylene film according to any one of the preceding claims.

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