Oriented polyethylene film and articles containing the same

Abstract

The present invention relates to an oriented multilayer polyethylene film. In one aspect, the biaxially oriented multilayer polyethylene film comprises: at least one layer, the layer comprising: (1) A polyethylene-based composition, (a) at least 97 wt. % of a polyethylene composition, based on the total weight of the polyethylene-based composition; (i) 0.935 to 0.947 g / cm 3 and a melt index (I2) of less than 0.1 g / 10 minutes; and (ii) 63 to 75 weight percent of a second polyethylene fraction; The polyethylene composition is 13 and a density of at least 0.965 g / cm3, as measured using C NMR. 3 The melt index (I2) of the polyethylene-based composition is 0.5 to 10 g / 10 min.

Description

Technical Field

[0001] The present invention relates to an oriented multilayer polyethylene film, a laminate including such a film, and an article including such a film and laminate.

Background Art

[0002] Introduction As the global interest in reducing packaging waste and making flexible packaging more sustainable becomes more certain, increasing efforts are being made to develop materials and technologies to enhance the sustainability of flexible packaging. Flexible packaging film structures are often formed of multiple types of polymeric materials, including, for example, polyethylene, polypropylene, ethylene vinyl alcohol, polyethylene terephthalate, polyamide, and the like. Such materials are typically combined to achieve a balance of properties not achievable with a single type of material. However, due to the differences in these materials, the final packaging is typically not easily recyclable. Thus, there is also a movement towards single-component structures (e.g., structures where all is polyethylene) to improve the recyclability profile. For example, in the case of a structure where all is polyethylene, certain performance metrics (e.g., mechanical properties) need to be enhanced in order to maintain the performance levels expected of these structures when formed from different polymeric materials while improving recyclability. Thus, new resins and processing technologies are needed to overcome the performance deficiencies of polyethylene compared to other types of materials.

[0003] One such relatively new material technology on the processing side is biaxially oriented polyethylene (BOPE) film. Such BOPE film is formed by cast extrusion and then oriented in the machine direction (MD), followed by orientation in the transverse direction (TD) with a tenter. Alternatively, this process may also be carried out simultaneously. Due to the molecular structure, microstructure, and crystallization kinetics of polyethylene, it is often difficult to biaxially orient conventional polyethylene.

[0004] It would be desirable to have new polyethylene-based compositions with good processability into biaxially oriented polyethylene films, as well as new biaxially oriented polyethylene films having desired and / or improved properties. It is also considered desirable to have new polyethylene-based compositions with good processability into uniaxially oriented (e.g., machine direction oriented) polyethylene films, as well as new uniaxially oriented polyethylene films having desired and / or improved properties. SUMMARY OF THE INVENTION

[0005] The present invention provides a biaxially oriented multilayer polyethylene film and a polyethylene-based composition suitable for processing into a biaxially oriented multilayer polyethylene film having desired and / or improved properties. Such a polyethylene-based composition can advantageously expand the processing window for stretching the film to provide a biaxially oriented polyethylene film in some embodiments. For example, by expanding the processing window for biaxial orientation, higher density polyethylene can be oriented, which can result in improved film rigidity. Other advantages include better film conversion and printability, improved optical properties (e.g., higher transparency and lower haze), improved barrier performance of metallized biaxially oriented polyethylene films, and, more generally, improved processability for wider and larger width extruders, but are not limited thereto. The present invention also provides a uniaxially oriented (e.g., longitudinally oriented) multilayer polyethylene film and a polyethylene-based composition suitable for processing into a uniaxially oriented multilayer polyethylene film having desired and / or improved properties.

[0006] In one aspect, the biaxially oriented multilayer polyethylene film comprises at least one layer, which layer (1) is a polyethylene-based composition, (a) is a polyethylene composition that is at least 97% by weight, based on the total weight of the polyethylene-based composition, (i) and comprises 25 to 37 weight percent of a first polyethylene fraction having a density in the range of 0.935 to 0.947 g / cm 3 and a melt index (I2) of less than 0.1 g / 10 min, and (ii) 63 to 75 weight percent of a second polyethylene fraction, and contains a polyethylene-based composition containing a polyethylene composition, the polyethylene composition of which 13 has less than 0.10 branches per 1,000 carbon atoms when measured using 13C NMR, and the density of the polyethylene-based composition is at least 0.965 g / cm 3and the melt index (I2) of the polyethylene-based composition is 0.5 to 10 g / 10 min.

[0007] In some embodiments, the polyethylene-based composition comprises at least 99 wt% of a polyethylene composition, based on the total weight of the polyethylene-based composition, and is substantially free of any nucleating agent. In some embodiments, the polyethylene-based composition contains 0 to 19 ppm of all nucleating agents combined. In some embodiments, the polyethylene-based composition is free of nucleating agents.

[0008] In some embodiments, the polyethylene-based composition further comprises 20 to 5000 ppm of a nucleating agent, based on the total weight of the polyethylene-based composition, and the nucleating agent comprises a calcium salt of 1,2-cyclohexanedicarboxylic acid or sodium 4-[(4-chlorobenzoyl)amino]benzoate.

[0009] In another aspect, the present invention relates to an article such as a food package. In one aspect, the article comprises any of the biaxially oriented multilayer polyethylene films disclosed herein.

[0010] In another aspect, the present invention relates to a laminate and an article formed from such a laminate. In some embodiments, the laminate comprises a first film comprising a polyethylene-based sealant film, polyethylene terephthalate, polypropylene, or polyamide, and an oriented multilayer polyethylene film according to any of the embodiments disclosed herein, and the first film is laminated to the multilayer polyethylene film. In one aspect, the article comprises any of the laminates disclosed herein.

[0011] These and other embodiments are described in more detail in the "Detailed Description of the Invention".

Detailed Description of the Invention

[0012] Unless there are conflicting statements, implied by context, or not conventional in the art, all parts and percentages are by weight, all temperatures are in °C, and all test methods are the latest as of the filing date of this disclosure.

[0013] As used herein, the term "composition" refers to a mixture of the materials that make up the composition, as well as reaction products and decomposition products formed from the materials of the composition.

[0014] "Polymer" means a polymeric compound prepared by polymerizing monomers, whether of the same or different types. Thus, the general term polymer encompasses the term homopolymer defined below and the term interpolymer defined below. Trace amounts of impurities (e.g., catalyst residues) may be incorporated into and / or within the polymer. A polymer can be a single polymer, a polymer blend, or a polymer mixture containing mixtures of polymers formed in situ during polymerization.

[0015] As used herein, the term "homopolymer" refers to a polymer prepared from only one type of monomer, with the understanding that trace amounts of impurities may be incorporated into the polymer structure.

[0016] As used herein, the term "interpolymer" refers to a polymer prepared by the polymerization of at least two different types of monomers. Thus, the general term interpolymer includes copolymers (used to refer to polymers prepared from two different types of monomers) and polymers prepared from three or more different types of monomers.

[0017] As used herein, the term "olefin-based polymer" or "polyolefin" refers to a polymer that contains, in polymerized form (based on the weight of the polymer), a majority amount of an olefin monomer, such as ethylene or propylene, and optionally may contain one or more comonomers.

[0018] As used herein, the term "ethylene / α-olefin interpolymer" refers to an interpolymer in polymerized form that contains, in a majority amount (more than 50 mol %), units derived from ethylene monomers and, in the remaining amount, units derived from one or more α-olefins. Typical α-olefins used in the formation of ethylene / α-olefin interpolymers are C3-C 10 alkenes.

[0019] As used herein, the term "ethylene / α-olefin copolymer" refers to a copolymer in polymerized form that contains, as only two types of monomers, a majority amount (more than 50 mol %) of ethylene monomers and an α-olefin.

[0020] As used herein, the term "α-olefin" refers to an alkene having a double bond at the primary or alpha (α) position.

[0021] "Polyethylene" or "ethylene-based polymer" shall mean a polymer containing a majority (more than 50 mol%) of units derived from ethylene monomers. This includes polyethylene homopolymers or copolymers (meaning units derived from two or more comonomers). Common forms of polyethylene known in the art include low density polyethylene (LDPE), linear low density polyethylene (LLDPE), ultra (extremely) low density polyethylene (ULDPE), very low density polyethylene (VLDPE), single-site catalyst linear low density polyethylene (m-LLDPE) including both linear and substantially linear low density resins, ethylene-based plastomer (POP) and ethylene-based elastomer (POE), medium density polyethylene (MDPE), and high density polyethylene (HDPE). These polyethylene materials are generally known in the art. However, the following description may help in understanding the differences among some of these different polyethylene resins.

[0022] The term "LDPE" may also be referred to as "high pressure ethylene polymer" or "highly branched polyethylene", but is defined to mean that the polymer is partially or completely homopolymerized or copolymerized in an autoclave or tubular reactor at a pressure above 14,500 psi (100 MPa) using a free radical initiator such as a peroxide (see, for example, US 4,599,392, which is incorporated by reference). LDPE resins typically have a density in the range of 0.916 - 0.935 g / cm 3 within the range.

[0023] The term "LLDPE" includes both resins made using single-site catalysts including, but not limited to, traditional Ziegler-Natta and chromium-based catalysts, and mono- or bis-cyclopentadienyl catalysts (typically referred to as metallocenes) and geometrically constrained catalysts, phosphine imine catalysts, and polyvalent aryloxy ether catalysts (typically referred to as bisphenol phenoxy), and includes linear, substantially linear, or heterogeneous polyethylene copolymers or homopolymers. LLDPE contains fewer long-chain branches than LDPE and is further defined in U.S. Patent No. 5,272,236, U.S. Patent No. 5,278,272, U.S. Patent No. 5,582,923, and U.S. Patent No. 5,733,155 as substantially linear ethylene polymers, homogeneous branched linear ethylene polymer compositions such as those of U.S. Patent No. 3,645,992, heterogeneous branched ethylene polymers prepared according to the process disclosed in U.S. Patent No. 4,076,698, and / or blends thereof (such as those disclosed in U.S. Patent No. 3,914,342 or U.S. Patent No. 5,854,045). LLDPE can be made via gas phase, solution phase, or slurry polymerization, or any combination thereof, using any type of reactor or reactor configuration known in the art.

[0024] The term "MDPE" refers to polyethylene having a density of 0.926 to 0.935 g / cm 3 ³. "MDPE" is typically manufactured using a chromium or Ziegler-Natta catalyst or using a single-site catalyst including, but not limited to, substituted mono- or bis-cyclopentadienyl catalysts (typically referred to as metallocenes), constrained geometry catalysts, phosphine imine catalysts, and polyvalent aryloxy ether catalysts (typically referred to as bisphenol phenoxy) and typically has a molecular weight distribution ("MWD") greater than 2.5.

[0025] The term "HDPE" refers to polyethylene prepared using single-site catalysts including, but not limited to, Ziegler-Natta catalysts, chromium catalysts, or substituted mono- or bis-cyclopentadienyl catalysts (typically referred to as metallocenes), geometrically constrained catalysts, phosphine imine catalysts, and polyvalent aryloxy ether catalysts (typically referred to as bisphenol phenoxy) and having a density of about 0.935 g / cm 3 to a maximum of about 0.980 g / cm 3 .

[0026] The term "ULDPE" refers to polyethylene prepared using single-site catalysts including, but not limited to, Ziegler-Natta catalysts, chromium catalysts, or substituted mono- or bis-cyclopentadienyl catalysts (typically referred to as metallocenes), geometrically constrained catalysts, phosphine imine catalysts, and polyvalent aryloxy ether catalysts (typically referred to as bisphenol phenoxy) and having a density of 0.855 - 0.912 g / cm 3 . ULDPE includes, but is not limited to, polyethylene (ethylene-based) plastomers and polyethylene (ethylene-based) elastomers. Polyethylene (ethylene-based) elastomers and plastomers generally have a density of 0.855 - 0.912 g / cm 3 .

[0027] The terms "blend", "polymer blend", and similar terms mean a composition of two or more polymers. Such blends may or may not be miscible. Such blends may or may not be phase-separated. Such blends may or may not contain one or more domain structures as determined by transmission electron spectroscopy, light scattering, X-ray scattering, and any other method known in the art. A blend is not a laminate, but one or more layers of a laminate may contain a blend. Such blends may be prepared as dry blends or in situ (e.g., in a reactor) as melt blends or formed using other techniques known to those skilled in the art.

[0028] The terms "comprising", "including", "having" and their derivatives are not intended to exclude the presence of any additional components, steps or procedures, whether or not specifically disclosed. To avoid any doubt, all compositions claimed through the use of the term "comprising" may include any additional additives, adjuvants or compounds, whether polymeric or otherwise, unless there is a contradictory description. In contrast, the term "consisting essentially of" excludes any other components, steps or procedures from the scope of any subsequent description, except those that are not essential for operation. The term "consisting of" excludes any component, step or procedure not specifically depicted or listed.

[0029] The present invention generally relates to an oriented multilayer polyethylene film. In some embodiments, such a film is biaxially oriented. In some embodiments, such a film is biaxially oriented using a tenter. In some embodiments, such a film is uniaxially oriented in the longitudinal direction. The oriented multilayer polyethylene film utilizes a polyethylene-based composition in at least one layer that can advantageously expand the processing window for stretching the film. For example, by expanding the processing window for biaxial orientation, higher density polyethylene can be oriented, which can also result in improved film rigidity. The oriented multilayer polyethylene film can be used for packaging applications in some embodiments.

[0030] In one aspect, the biaxially oriented multilayer polyethylene film comprises at least one layer, which (1) is a polyethylene-based composition, (a) is at least 97 wt% polyethylene composition based on the total weight of the polyethylene-based composition, (i) 0.935 - 0.947 g / cm 3a polyethylene-based composition comprising a polyethylene composition having a density in the range of and a melt index (I2) of less than 0.1 g / 10 min, and (ii) a second polyethylene fraction of 63 to 75 weight percent, the polyethylene composition, 13 when measured using 13C NMR, has less than 0.10 branches per 1,000 carbon atoms, and the density of the polyethylene-based composition is at least 0.965 g / cm 3 and the melt index (I2) of the polyethylene-based composition is 0.5 to 10 g / 10 min. In some embodiments, the polyethylene-based composition consists of 100 weight % of the polyethylene composition. In some embodiments, the polyethylene-based composition consists essentially of at least 99 weight % of the polyethylene composition.

[0031] In some embodiments, the polyethylene-based composition comprises at least 99 weight % of the polyethylene composition, based on the total weight of the polyethylene-based composition, and is substantially free of any nucleating agent.

[0032] In some embodiments, the polyethylene-based composition is substantially free of any nucleating agent. The amount of nucleating agent present in the polyethylene-based composition can be detected by elemental analysis using X-ray fluorescence (XRF), using techniques known to those skilled in the art. As used herein, in embodiments where the polyethylene-based composition is substantially free of any nucleating agent, the polyethylene-based composition contains less than 0-19 ppm of all nucleating agents combined. In some embodiments, the polyethylene-based composition is free of any nucleating agent. In some embodiments, the polyethylene-based composition contains calcium salt of 1,2-cyclohexanedicarboxylic acid or sodium 4-[(4-chlorobenzoyl)amino]benzoate in an amount of less than 0-19 ppm. In some embodiments, the polyethylene-based composition is free of any calcium salt of 1,2-cyclohexanedicarboxylic acid or sodium 4-[(4-chlorobenzoyl)amino]benzoate.

[0033] The absence or substantial absence of a nucleating agent in the polyethylene-based composition has been found to provide beneficial results after film orientation. However, in some embodiments, one or more nucleating agents can be provided in the polyethylene-based composition. In some embodiments, the polyethylene-based composition contains 20-2000 ppm of a nucleating agent, based on the total weight of the polyethylene-based composition.

[0034] In one aspect, the biaxially oriented multilayer polyethylene film comprises at least one layer, which layer is (1) a polyethylene-based composition, wherein (a) at least 97 wt% of a polyethylene composition, based on the total weight of the polyethylene-based composition, wherein (i) having a density in the range of 0.935-0.947 g / cm 3 and a melt index (I2) of less than 0.1 g / 10 min, 25-37 weight percent of a first polyethylene fraction, and (ii) a polyethylene composition comprising 63 to 75 weight percent of a second polyethylene fraction, and (b) a polyethylene-based composition comprising, based on the total weight of the polyethylene-based composition, 20 to 5000 ppm of a nucleating agent comprising a calcium salt of 1,2-cyclohexanedicarboxylic acid or sodium 4-[(4-chlorobenzoyl)amino]benzoate, The polyethylene composition 13 has less than 0.10 branches per 1000 carbon atoms when measured using 13C NMR, and the density of the polyethylene-based composition is at least 0.965 g / cm 3 and the melt index (I2) of the polyethylene-based composition is 0.5 to 10 g / 10 min.

[0035] In another aspect, the biaxially oriented multilayer polyethylene film comprises at least one layer, and this layer (1) is a polyethylene-based composition, (a) at least 97 weight percent of a polyethylene composition based on the total weight of the polyethylene-based composition, (i) a first polyethylene fraction having a density in the range of 0.935 to 0.947 g / cm 3 and a melt index (I2) of less than 0.1 g / 10 min, 25 to 37 weight percent, (ii) a second polyethylene fraction of 63 to 75 weight percent, and (b) a polyethylene-based composition comprising, based on the total weight of the polyethylene-based composition, 20 to 5000 ppm of a nucleating agent comprising sodium 4-[(4-chlorobenzoyl)amino]benzoate, The polyethylene composition 13 has less than 0.10 branches per 1000 carbon atoms when measured using 13C NMR, and the density of the polyethylene-based composition is at least 0.965 g / cm 3 and the melt index (I2) of the polyethylene-based composition is 0.5 to 10 g / 10 min.

[0036] In another aspect, the biaxially oriented multilayer polyethylene film comprises at least one layer, and this layer is (1) a polyethylene-based composition, (a) a polyethylene composition that is at least 97 wt% based on the total weight of the polyethylene-based composition, (i) 25 to 37 weight percent of a first polyethylene fraction having a density in the range of 0.935 to 0.947 g / cm 3 and a melt index (I2) of less than 0.1 g / 10 min, and (ii) 63 to 75 weight percent of a second polyethylene fraction, and a polyethylene composition containing the same, (b) a nucleating agent that is 20 to 5000 ppm based on the total weight of the polyethylene-based composition, and a nucleating agent containing a calcium salt of 1,2-cyclohexanedicarboxylic acid, and a polyethylene-based composition containing the same, The polyethylene composition 13 has less than 0.10 branches per 1000 carbon atoms as measured using 13C NMR, the density of the polyethylene-based composition is at least 0.965 g / cm 3 and the melt index (I2) of the polyethylene-based composition is 0.5 to 10 g / 10 min.

[0037] In some embodiments, the biaxially oriented film according to any of the embodiments described herein is oriented in the longitudinal direction at a draw ratio of 2:1 to 9:1 and in the transverse direction at a draw ratio of 2:1 to 11:1. In some embodiments, the biaxially oriented film is oriented in the longitudinal direction at a draw ratio of 2:1 to 6:1 and in the transverse direction at a draw ratio of 2:1 to 9:1. In some embodiments, the biaxially oriented film is oriented in the longitudinal direction at a draw ratio of 4:1 to 6:1 and in the transverse direction at a draw ratio of 6:1 to 9:1.

[0038] In some embodiments, the biaxially oriented multilayer polyethylene film further comprises a second polyethylene composition, and the second polyethylene composition exhibits at least two local peaks in the comonomer distribution measured by crystallization elution fractionation, excluding the soluble fraction, and one of those peaks is at 40°C to 95°C. In some embodiments, the second polyethylene composition exhibits at least two local peaks in the comonomer distribution measured by crystallization elution fractionation, excluding the soluble fraction, and one of those peaks is at 40°C to 90°C. In some embodiments, the second polyethylene composition exhibits at least two local peaks in the comonomer distribution measured by crystallization elution fractionation, excluding the soluble fraction, and one of those peaks is at 40°C to 87°C. The second polyethylene composition has a density of 0.928 to 0.940 g / cm 3 in some embodiments. In some embodiments, the layer containing the polyethylene-based composition further comprises the second polyethylene composition.

[0039] In some embodiments, the overall density of the biaxially oriented multilayer film is 0.931 to 0.975 g / cm 3 .

[0040] In some embodiments, the biaxially oriented multilayer film has a thickness of 5 to 50 μm.

[0041] In some embodiments, the biaxially oriented multilayer film further comprises a layer containing polyamide or ethylene vinyl alcohol.

[0042] In some embodiments, the biaxially oriented multilayer film further comprises an outer layer that is a sealant layer.

[0043] In some embodiments, the biaxially oriented multilayer film further includes an outer layer that provides a matte surface. In such embodiments, the outer layer has a glossiness of less than 50% when measured according to ASTM D2457 and at an angle of 45°. To provide a matte surface, the outer layer can include 20 to 80 wt% of an ethylene-based polymer and 80 to 20 wt% of a propylene-based polymer, as described in International Publication No. WO 2020 / 001191, which is incorporated herein by reference. For example, in some embodiments, the outer layer includes a blend of linear low density polyethylene and a propylene random copolymer.

[0044] In some embodiments, the biaxially oriented multilayer film further includes a layer containing a metal deposited on the outer layer of the film, and the metal includes Al, Zn, Au, Ag, Cu, Ni, Cr, Ge, Se, Ti, Sn, Si, Mg, or oxides thereof.

[0045] In another aspect, the present invention relates to an article such as food packaging. In one aspect, the article includes any one of the biaxially oriented multilayer polyethylene films of the present invention disclosed herein.

[0046] In another aspect, the present invention relates to a laminate and an article formed from such a laminate. In some embodiments, the laminate includes a first film including a polyethylene-based sealant film, polyethylene terephthalate, polypropylene, or polyamide, and a biaxially oriented multilayer polyethylene film according to any of the embodiments disclosed herein, and the first film is laminated to the multilayer polyethylene film. In one aspect, the article includes any of the laminates disclosed herein.

[0047] In another aspect, the present invention is a uniaxially oriented multilayer polyethylene film, including at least one layer, and the layer is (1) a polyethylene-based composition, (a) A polyethylene-based composition comprising at least 97% by weight of a polyethylene composition, based on the total weight of the polyethylene-based composition, (i) 25 to 37 weight percent of a first polyethylene fraction having a density in the range of 0.935 to 0.947 g / cm 3 and a melt index (I2) of less than 0.1 g / 10 min, and (ii) 63 to 75 weight percent of a second polyethylene fraction, wherein the polyethylene composition has, when measured using 13 C NMR, less than 0.10 branches per 1,000 carbon atoms, and the density of the polyethylene-based composition is at least 0.965 g / cm 3 and the melt index (I2) of the polyethylene-based composition is 0.5 to 10 g / 10 min. In some embodiments, the film is oriented in the longitudinal direction. In some embodiments, the polyethylene-based composition consists of 100% by weight of the polyethylene composition. In some embodiments, the polyethylene-based composition consists essentially of at least 99% by weight of the polyethylene composition.

[0048] In some embodiments, the polyethylene-based composition comprises at least 99% by weight of the polyethylene composition, based on the total weight of the polyethylene-based composition, and is substantially free of any nucleating agent.

[0049] In some embodiments, the polyethylene-based composition is substantially free of any nucleating agent. As used herein, in embodiments where the polyethylene-based composition is substantially free of any nucleating agent, the polyethylene-based composition contains from 0 to 19 ppm of all nucleating agents combined. In some embodiments, the polyethylene-based composition is free of any nucleating agent. In some embodiments, the polyethylene-based composition contains calcium salt of 1,2-cyclohexanedicarboxylic acid or 4-[(4-chlorobenzoyl)amino]benzoic acid in an amount less than 0 to 19 ppm. In some embodiments, the polyethylene-based composition is free of any calcium salt of 1,2-cyclohexanedicarboxylic acid or sodium 4-[(4-chlorobenzoyl)amino]benzoate.

[0050] The absence or substantial absence of a nucleating agent in the polyethylene-based composition has been found to provide beneficial results after film orientation. However, in some embodiments, one or more nucleating agents can be provided in the polyethylene-based composition. In some embodiments, the polyethylene-based composition contains from 20 to 2000 ppm of a nucleating agent, based on the total weight of the polyethylene-based composition.

[0051] In another aspect, the present invention is a uniaxially oriented multilayer polyethylene film, comprising at least one layer, the layer being (1) a polyethylene-based composition, (a) a polyethylene composition comprising at least 97 wt% of a polyethylene composition, based on the total weight of the polyethylene-based composition, (i) a first polyethylene fraction having a density in the range of 0.935 to 0.947 g / cm 3 and a melt index (I2) of less than 0.1 g / 10 min, and (ii) a second polyethylene fraction of 63 to 75 wt%, (b) A polyethylene-based composition comprising a nucleating agent in an amount of 20 to 5000 ppm based on the total weight of the polyethylene-based composition, the nucleating agent comprising a calcium salt of 1,2-cyclohexanedicarboxylic acid or sodium 4-[(4-chlorobenzoyl)amino]benzoate, The polyethylene composition is 13 When measured using 13C NMR, it has less than 0.10 branches per 1000 carbon atoms, and the density of the polyethylene-based composition is at least 0.965 g / cm 3 and the melt index (I2) of the polyethylene-based composition is 0.5 to 10 g / 10 min. In some embodiments, the film is oriented in the longitudinal direction.

[0052] In another aspect, the present invention is a uniaxially oriented multilayer polyethylene film comprising at least one layer, the layer being (1) a polyethylene-based composition comprising (a) a polyethylene composition of at least 97% by weight based on the total weight of the polyethylene-based composition, the polyethylene composition comprising (i) a first polyethylene fraction of 25 to 37 weight percent having a density in the range of 0.935 to 0.947 g / cm 3 and a melt index (I2) of less than 0.1 g / 10 min, and (ii) a second polyethylene fraction of 63 to 75 weight percent, (b) a polyethylene-based composition comprising a nucleating agent in an amount of 20 to 5000 ppm based on the total weight of the polyethylene-based composition, the nucleating agent comprising a calcium salt of 1,2-cyclohexanedicarboxylic acid, The polyethylene composition is 13 When measured using 13C NMR, it has less than 0.10 branches per 1000 carbon atoms, and the density of the polyethylene-based composition is at least 0.965 g / cm 3and the melt index (I2) of the polyethylene-based composition is 0.5 to 10 g / 10 min. In some embodiments, the film is oriented in the longitudinal direction.

[0053] In another aspect, the present invention is a uniaxially oriented multilayer polyethylene film, comprising at least one layer, the layer being (1) a polyethylene-based composition, (a) a polyethylene composition that is at least 97 wt% based on the total weight of the polyethylene-based composition, (i) 25 to 37 weight percent of a first polyethylene fraction having a density in the range of 0.935 to 0.947 g / cm 3 and a melt index (I2) of less than 0.1 g / 10 min, and (ii) 63 to 75 weight percent of a second polyethylene fraction, and (b) a nucleating agent that is 20 to 5000 ppm based on the total weight of the polyethylene-based composition, the nucleating agent comprising sodium 4-[(4-chlorobenzoyl)amino]benzoate, the polyethylene composition 13 has less than 0.10 branches per 1000 carbon atoms as measured using 13C NMR, and the density of the polyethylene-based composition is at least 0.965 g / cm 3and the melt index (I2) of the polyethylene-based composition is from 0.5 to 10 g / 10 min. In some embodiments, the film is oriented in the longitudinal direction. In some embodiments, the uniaxially oriented film is oriented in the longitudinal direction with a draw ratio of from 4:1 to 20:1. In some embodiments, the uniaxially oriented film is oriented in the longitudinal direction with a draw ratio of from 4:1 to 16:1. In some embodiments, the uniaxially oriented film is oriented in the longitudinal direction with a draw ratio of from 4:1 to 12:1. In some embodiments, the uniaxially oriented film is oriented in the longitudinal direction with a draw ratio of from 4:1 to 10:1. In some embodiments, the uniaxially oriented film is oriented in the longitudinal direction with a draw ratio of from 4:1 to 9:1.

[0054] In some embodiments, the uniaxially oriented multilayer polyethylene film further comprises a second polyethylene composition, and the second polyethylene composition exhibits at least two local peaks in the comonomer distribution measured by crystallization elution fractionation, excluding the soluble fraction, and one of those peaks is from 40 °C to 95 °C. In some embodiments, the fraction forming the peak from 40 °C to 95 °C is up to 50 weight percent of the composition when measured by crystallization elution fractionation. The second polyethylene composition, in some embodiments, exhibits at least two local peaks in the comonomer distribution measured by crystallization elution fractionation, excluding the soluble fraction, and one of those peaks is from 40 °C to 90 °C. In some embodiments, the second polyethylene composition exhibits at least two local peaks in the comonomer distribution measured by crystallization elution fractionation, excluding the soluble fraction, and one of those peaks is from 40 °C to 87 °C. The second polyethylene composition, in some embodiments, has a density of from 0.928 to 0.940 g / cm 3 In some embodiments, the layer comprising the polyethylene-based composition further comprises the second polyethylene composition.

[0055] In some embodiments, the overall density of the uniaxially oriented multilayer film is from 0.931 to 0.975 g / cm 3 is.

[0056] In some embodiments, the uniaxially oriented multilayer film has a thickness of 5 to 50 μm.

[0057] The uniaxially oriented multilayer film further comprises, in some embodiments, a layer comprising polyamide or ethylene vinyl alcohol.

[0058] In some embodiments, the uniaxially oriented multilayer film further comprises an outer layer that is a sealant layer.

[0059] In some embodiments, the uniaxially oriented multilayer film further comprises a layer containing a metal deposited on the outer layer of the film, and the metal comprises Al, Zn, Au, Ag, Cu, Ni, Cr, Ge, Se, Ti, Sn, Si, Mg, or oxides thereof.

[0060] In another aspect, the present invention relates to an article such as a food package. In one aspect, the article comprises any one of the uniaxially oriented multilayer polyethylene films of the present invention disclosed herein.

[0061] In another aspect, the present invention relates to a laminate and an article formed from such a laminate. In some embodiments, the laminate comprises a first film comprising a polyethylene-based sealant film, polyethylene terephthalate, polypropylene, or polyamide, and a uniaxially oriented multilayer polyethylene film according to any of the embodiments disclosed herein, and the first film is laminated to the multilayer polyethylene film. In one aspect, the article comprises any of the laminates disclosed herein.

[0062] Polyethylene composition As discussed above, the biaxially oriented (or uniaxially oriented) multilayer film of the present invention comprises at least one layer comprising a polyethylene-based composition having certain properties. The polyethylene-based composition used in the embodiments of the present invention has a density of (i) 0.935 to 0.947 g / cm 3A polyethylene composition comprising: (i) a first polyethylene fraction of 25 to 37 weight percent having a density in the range of and a melt index (I2) of less than 0.1 g / 10 min; and (ii) a second polyethylene fraction of 63 to 75 weight percent. The polyethylene composition, 13 when measured using 13C NMR, has less than 0.10 branches per 1,000 carbon atoms, and the density of the polyethylene-based composition is at least 0.965 g / cm 3 and the melt index (I2) of the polyethylene-based composition is 0.5 to 10 g / 10 min.

[0063] In some embodiments, the polyethylene-based composition has a melt index (I2) of 2.5 g / 10 min or less.

[0064] In some embodiments, the polyethylene composition has a density in the range of 0.940 to 0.947 g / cm 3 and comprises a first polyethylene fraction of 25 to 37 weight percent having a density in the range of and a second polyethylene fraction of 63 to 75 weight percent having a density of 0.970 g / cm 3 or more.

[0065] The polyethylene composition may comprise a combination of two or more of the embodiments described herein.

[0066] In one embodiment, the polyethylene composition has a density of at least 0.965 g / cm 3 In some embodiments, the polyethylene composition has a density of at least 0.968 g / cm 3 In some embodiments, the polyethylene composition has a density of up to 0.976 g / cm 3 In some embodiments, the polyethylene composition has a density in the range of 0.965 to 0.976 g / cm 3 , for example, 0.965 to 0.970, or 0.967 to 0.969, or 0.965 to 0.970 g / cm 3 For example, the density has a lower limit of 0.965 or 0.967 g / cm3 and its upper limit is 0.970, 0.972, 0.975, or 0.976 g / cm 3 and can be.

[0067] The polyethylene composition has a melt index (I2 or I2 at 190 °C / 2.16 kg) of 0.5 to 10 g / 10 min. For example, the melt index (I2 or I2 at 190 °C / 2.16 kg) has a lower limit of 0.5, 0.7, 0.9, 1.0, 1.1, 1.2, 1.5, 2, 3, 4, or 5 g / 10 min and an upper limit of 1.5, 2, 2.5, 3, 4, 5, 6, 7, 8, 9, or 10 g / 10 min. In some embodiments, the polyethylene composition has a melt index (I2) of 0.5 to 5 g / 10 min, or 0.5 to 2.5 g / 10 min, or 0.7 to 3 g / 10 min, or 1.0 to 2.0 g / 10 min, or 1.0 to 1.5 g / 10 min.

[0068] In some embodiments, the polyethylene composition has a melt index ratio (I 10 / I2) of 10 or more. The polyethylene composition, in some embodiments, has a melt index ratio (I 10 / I2) of up to 17. In some embodiments, the polyethylene composition has a melt index ratio (I 10 / I2) of 10 to 17. The polyethylene composition, in some embodiments, has a melt index ratio (I 10 / I2) of 12 to 17.

[0069] The polyethylene composition has a low level of branching. The polyethylene composition, in some embodiments, 13 has less than 0.10 branches per 1,000 carbon atoms when measured using 13C NMR. The polyethylene composition, in some embodiments, 13 has less than 0.07 branches per 1,000 carbon atoms when measured using 13C NMR. The polyethylene composition, in some embodiments, 13When measured using 13C NMR, it has less than 0.05 branches per 1,000 carbon atoms. In some embodiments, the polyethylene composition 13 When measured using 13C NMR, it has less than 0.03 branches per 1,000 carbon atoms.

[0070] In some embodiments, the polyethylene composition has a low level of non-vinyl unsaturation. In some embodiments, the polyethylene composition 1 When measured using 1H NMR, it has less than 25 non-vinyl unsaturations per 1 million carbon atoms. The polyethylene composition, in some embodiments 1 When measured using 1H NMR, it has less than 20 non-vinyl unsaturations per 1 million carbon atoms.

[0071] Without wishing to be bound by theory, the combination of a low level of branching and a low level of non-vinyl unsaturation in the polyethylene composition is thought to provide a greater amount of crystallinity in the polyethylene composition, thereby improving its barrier properties when formed into a film.

[0072] In one embodiment, the polyethylene composition has a ZSVR value of less than 2.0, or from 1.0 to 2.0, or from 1.2 to 1.8, or from 1.3 to 1.7.

[0073] In one embodiment, the polyethylene composition has a value represented as the molecular weight distribution, i.e., the ratio of the weight average molecular weight to the number average molecular weight (M w / M n , determined by conventional GPC) within the range of 8.0 to 14.0. For example, the molecular weight distribution (M w / M n ) can have a lower limit of 8.0, 8.5, 9.0, or 9.5 and an upper limit of 10.0, 11.0, 11.5, 12.0, 12.5, 13.0, 13.5, or 14.0. In some embodiments, M w / M n is from 10.0 to 12.0.

[0074] In one embodiment, the number average molecular weight (M n , determined by conventional GPC) of the polyethylene composition is in the range of 8,000 to 20,000 g / mol. For example, the number average molecular weight may have a lower limit of 8,000, 9,000, 10,000, or 11,000 g / mol and an upper limit of 12,000, 13,000, 15,000, or 20,000 g / mol.

[0075] In one embodiment, the polyethylene composition has a weight average molecular weight (M w , determined by conventional GPC) in the range of 100,000 to 125,000 g / mol. For example, the weight average molecular weight may have a lower limit of 100,000, 105,000, or 110,000 g / mol and an upper limit of 115,000, 120,000, or 124,000 g / mol.

[0076] In one embodiment, the polyethylene composition has a z-average molecular weight (M Z , determined by conventional GPC) of at least 350,000 g / mol, for example in the range of 350,000 to 600,000 g / mol or the like. For example, the z-average molecular weight may have a lower limit of 350,000, 375,000, 400,000, 405,000, or 410,000 g / mol and an upper limit of 420,000, 425,000, 450,000, 475,000, 500,000, 550,000, or 600,000 g / mol.

[0077] In one embodiment, the polyethylene composition has an M z / M w ratio (each determined by conventional GPC) that is greater than 3.0. The polyethylene composition has an M z / M w ratio (each determined by conventional GPC) that is greater than 3.5 in some embodiments. M z / M w can be 3.0 to 4.0 in some embodiments, or 3.5 to 4.5 in some embodiments, or 3.5 to 4.0 in some embodiments.

[0078] In one embodiment, the polyethylene composition has a ZSVR of less than 2.0 and an M z / M w ratio (each determined by conventional GPC) of greater than 3.0. In another embodiment, the polyethylene composition has a ZSVR of less than 2.0 and an M z / M w ratio (each determined by conventional GPC) of greater than 3.5.

[0079] The polyethylene composition used in the polyethylene-based composition of the present invention comprises two fractions of polyethylene.

[0080] The first polyethylene fraction has a density of 0.935 to 0.947 g / cm 3 In some embodiments, the first polyethylene fraction has a density of 0.940 to 0.947 g / cm 3 The first polyethylene fraction has a melt index (I2) of less than 0.1 g / 10 min. In some embodiments, the first polyethylene fraction has a melt index (I2) of 0.01 g / 10 min or more. In some embodiments, the first polyethylene fraction has a melt index of 0.05 to 0.1 g / 10 min. In some embodiments, the first polyethylene fraction has 13 less than 0.10 branches per 1,000 carbon atoms when measured using 13C NMR.

[0081] In some embodiments, the second polyethylene fraction has a density of 0.970 g / cm 3 In some embodiments, the first polyethylene fraction has a density of 0.940 to 0.947 g / cm 3 and the second polyethylene fraction has a density of 0.970 g / cm 3It has the above density. In some embodiments, the second polyethylene fraction has a melt index (I2) of at least 100 g / 10 min. In some embodiments, the second polyethylene fraction has a melt index (I2) of at least 100 g / 10 min and up to and including 10,000 g / 10 min. The second polyethylene fraction has a melt index (I2) of at least 100 g / 10 min and up to and including 10,000 g / 10 min. The second polyethylene fraction has a melt index (I2) of at least 100 g / 10 min and up to and including 1,000 g / 10 min.

[0082] In some embodiments, the ratio of the melt index (I2) of the second polyethylene fraction to the melt index (I2) of the first polyethylene fraction is at least 1,000.

[0083] The polyethylene composition comprises 25 to 37 weight percent of a first polyethylene fraction and 63 to 75 weight percent of a second polyethylene fraction, based on the total weight of the polyethylene composition. In some embodiments, the polyethylene composition comprises 30 to 37 weight percent of a first polyethylene fraction and 63 to 70 weight percent of a second polyethylene fraction, based on the total weight of the polyethylene composition.

[0084] The polyethylene-based composition comprises at least 97 weight % of the polyethylene composition, based on the total weight of the polyethylene-based composition. In some embodiments, the polyethylene-based composition comprises up to 99 weight % of the polyethylene composition, based on the total weight of the polyethylene-based composition. In some embodiments, the polyethylene-based composition comprises 97 weight % to 98 weight % of the polyethylene composition, based on the total weight of the polyethylene-based composition.

[0085] The following discussion focuses on the preparation of the polyethylene composition for use in embodiments of the present invention.

[0086] Polymerization A polyethylene composition can be produced using any conventional polymerization process. Such conventional polymerization processes include slurry polymerization processes, solution polymerization processes that use one or more conventional reactors, such as loop reactors, isothermal reactors, stirred tank reactors, parallel, continuous batch reactors, and / or any combination thereof, but are not limited thereto. The polyethylene composition can be produced, for example, via a solution phase polymerization process that uses one or more loop reactors, isothermal reactors, and combinations thereof.

[0087] Generally, the solution phase polymerization process can occur in one or more well-stirred reactors, such as one or more isothermal loop reactors or one or more adiabatic reactors, at a temperature in the range of 115 to 250 °C, for example, 115 to 200 °C, and a pressure in the range of 300 to 1,000 psi, for example, 400 to 750 psi. In some embodiments, the temperature of the first reactor is in the range of 115 to 190 °C, for example, 115 to 175 °C, and the temperature of the second reactor is in the range of 150 to 250 °C, for example, 130 to 165 °C. In other embodiments, in a single reactor, the temperature of the reactor is in the range of 115 to 250 °C, for example, 115 to 225 °C.

[0088] The residence time in the solution phase polymerization process can be in the range of 2 to 30 minutes, for example, 10 to 20 minutes. Ethylene, a solvent, hydrogen, one or more catalyst systems, optionally one or more cocatalysts, and optionally one or more comonomers are continuously fed into one or more reactors. Exemplary solvents include, but are not limited to, isoparaffin. For example, such a solvent is commercially available from ExxonMobil Chemical Co. (Houston, Texas) under the name ISOPAR E. The resulting mixture of the polyethylene composition and the solvent is then removed from the reactor, and the polyethylene composition is isolated. The solvent is typically recovered via a solvent recovery unit, i.e., a heat exchanger and a gas-liquid separation drum, and then recycled to the polymerization system.

[0089] In one embodiment, the polyethylene composition can be produced by solution polymerization in a dual reactor system, such as a dual loop reactor system, where ethylene is polymerized in the presence of one or more catalyst systems. In some embodiments, only ethylene is polymerized. Additionally, one or more cocatalysts may be present. In another embodiment, the polyethylene composition can be produced by solution polymerization in a single reactor system, such as a single loop reactor system, where ethylene is polymerized in the presence of two catalyst systems. In some embodiments, only ethylene is polymerized.

[0090] Catalyst system Specific embodiments of catalyst systems that can be used to produce the polyethylene compositions described herein are described herein. It should be understood that the catalyst systems of the present disclosure may be implemented in different forms and should not be construed as limited to the specific embodiments described in the present disclosure. Rather, the embodiments are provided so that the present disclosure will be thorough and complete and will fully convey the scope of the subject matter to those skilled in the art.

[0091] The term "independently selected" means that R 1 , R 2 , R 3 , R 4 , and R 5 such R groups may be the same or different (e.g., R 1 , R 2 , R 3 , R 4 , and R 5 are all substituted alkyl, or R 1 and R 2 are substituted alkyl and R 3 may be aryl, etc.). The use of the singular includes the use of the plural and vice versa (e.g., a hexane solvent includes multiple hexanes). The named R groups will generally have structures recognized as corresponding to R groups having that name in the art. These definitions are intended to supplement and exemplify, not exclude, definitions known to those skilled in the art.

[0092] The term "precursor catalyst" 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 precursor catalyst to convert it into a catalytically active catalyst. As used herein, the terms "promoter" and "activator" are interchangeable terms.

[0093] When used to describe a particular carbon atom-containing chemical group, the expression within parentheses having 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 from 1 to 40 carbon atoms in its unsubstituted form. In some embodiments and general structures, a particular chemical group may be substituted by one or more substituents such as R S . The R x -substituted form of a chemical group defined using parentheses of the form "(C y )" may contain more than y carbon atoms, depending on the identity of any group R S . For example, "(C1~C S ) alkyl, where R S is phenyl (-C6H5) and is substituted by exactly one group R S " may contain from 7 to 46 carbon atoms. Thus, generally, when a chemical group defined using parentheses of the form "(C 40 )" is substituted by one or more carbon atom-containing substituents R x ~C y , the minimum and maximum total number of carbon atoms of the chemical group is determined by adding to both x and y the total number of carbon atoms from all carbon atom-containing substituents R S . S

[0094] The term "substituted" means that at least one 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 ​is meant to be replaced by. The term "over-substituted" means that all hydrogen atoms (H) bonded to the carbon or heteroatom of the corresponding unsubstituted compound or functional group are replaced by a substituent (e.g., R S ) is meant to be replaced by. The term "multi-substituted" means that at least two, but less than all, of the hydrogen atoms bonded to the carbon or heteroatom of the corresponding unsubstituted compound or functional group are replaced by a substituent.

[0095] The term "-H" means hydrogen or a hydrogen group covalently bonded to another atom. "Hydrogen" and "-H" are interchangeable and mean the same thing unless otherwise specified.

[0096] "(C1-C 40 ) hydrocarbyl" means a hydrocarbon radical having 1 to 40 carbon atoms, and the term "(C1-C 40 ) hydrocarbylene" means a hydrocarbon diradical having 1 to 40 carbon atoms, and each hydrocarbon radical and each hydrocarbon diradical is aromatic or non-aromatic, saturated or unsaturated, straight-chain or branched-chain, cyclic (including monocyclic and polycyclic, including fused and non-fused polycyclic containing bicyclic and containing 3 or more carbon atoms) or acyclic, unsubstituted or substituted by one or more R S .

[0097] In the present disclosure, (C1-C 40 ) hydrocarbyl can 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 ) alkylene. In some embodiments, each of the aforementioned (C1-C 40 ) hydrocarbyl groups has a maximum of 20 carbon atoms (i.e., (C1-C 20In other embodiments, it has up to 12 carbon atoms.

[0098] “(C1-C 40 )alkyl” and “(C1-C 18 )alkyl” each mean a saturated straight-chain or branched-chain hydrocarbon radical of 1 to 40 carbon atoms or 1 to 18 carbon atoms, which is unsubstituted or substituted by one or more R 40 )alkyl. Examples of unsubstituted (C1-C 20 )alkyl are unsubstituted (C1-C 10 )alkyl, unsubstituted (C1-C 40 )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. Examples of substituted (C1-C 20 )alkyl include substituted (C1-C 10 )alkyl, substituted (C1-C 45 )alkyl, trifluoromethyl, and [C 45 alkyl. The term “[C S alkyl (in square brackets)” means that there are up to 45 carbon atoms in the radical including substituents. For example, (C 27 -C 40 )alkyl substituted by one R

[0099] “(C6-C 40 )aryl” means an unsubstituted or substituted (by one or more R Smeans a monocyclic, bicyclic, or tricyclic aromatic hydrocarbon radical, wherein at least 6 to 14 carbon atoms are aromatic ring carbon atoms, and the monocyclic, bicyclic, or tricyclic radical contains 1, 2, or 3 rings respectively. In the formula, one ring is aromatic, and 2 or 3 rings are independently fused or unfused, and at least one of the 2 or 3 rings is an aromatic ring. Unsubstituted (C6-C 40 ) aryl examples include 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, indacenyl, hexahydroindacenyl, indenyl, dihydroindenyl, naphthyl, tetrahydronaphthyl, and phenanthrene. Substituted (C6-C 40 ) aryl examples include substituted (C1-C 20 ) aryl, substituted (C6-C 18 ) aryl, 2,4-bis[(C 20 ) alkyl]-phenyl, polyfluorophenyl, pentafluorophenyl, and fluoren-9-one-1-yl.

[0100] The term “(C3-C 40 ) cycloalkyl” means a saturated cyclic hydrocarbon radical of 3 to 40 carbon atoms that is unsubstituted or substituted with one or more R S . Other cycloalkyl groups (e.g., (C x -C y ) cycloalkyl) are defined in a similar manner, either having x to y carbon atoms and being unsubstituted or substituted with one or more R S . Examples of unsubstituted (C3-C 40 ) cycloalkyl include unsubstituted (C3-C 20 ) cycloalkyl, unsubstituted (C3-C 10 ) cycloalkyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, and cyclodecyl. Substituted (C3-C 40)Examples of cycloalkyl include substituted (C3-C 20 )cycloalkyl, substituted (C3-C 10 )cycloalkyl, cyclopentanone-2-yl, and 1-fluorocyclohexyl.

[0101] (Examples of (C1-C 40 )hydrocarbylene include substituted or unsubstituted (C6-C 40 )arylene, (C3-C 40 )cycloalkylene, (C1-C 40 )alkylene (e.g., (C1-C 20 )alkylene). In some embodiments, the diradical is on the same carbon atom (e.g., -CH2-), or on adjacent carbon atoms (i.e., 1,2-diradical), or separated by one, two, or more intervening carbon atoms (e.g., each 1,3-diradical, 1,4-diradical, etc.). Some diradicals include α,ω-diradicals. An α,ω-diradical is a diradical having the maximum carbon backbone spacing between the radical carbons. Some examples of (C2-C 20 )alkylene α,ω-diradicals include ethane-1,2-diyl (i.e., -CH2CH2-), propane-1,3-diyl (i.e., -CH2CH2CH2-), 2-methylpropane-1,3-diyl (i.e., -CH2CH(CH3)CH2-). Some examples of (C6-C 50 )arylene α,ω-diradicals include phenyl-1,4-diyl, naphthalene-2,6-diyl, or naphthalene-3,7-diyl.

[0102] The term “(C1-C 40) alkylene” means an unsubstituted or one or more R S substituted saturated straight-chain or branched-chain diradical of 1 to 40 carbon atoms (i.e., the radical is not on a ring atom). Unsubstituted (C1-C 50)Examples of alkylene are unsubstituted -CH2CH2-, -(CH2)3-, -(CH2)4-, -(CH2)5-, -(CH2)6-, -(CH2)7-, -(CH2)8-, -CH2C * HCH3, and -(CH2)4C * (H)(CH3), which are unsubstituted (C1-C 20 ) alkylene, where the "C * " represents a carbon atom from which a hydrogen atom has been removed to form a secondary or tertiary alkyl group. Examples of substituted (C1-C 50 ) alkylene are substituted (C1-C 20 ) alkylene, -CF2-, -C(O)-, and -(CH2) 14 C(CH3)2(CH2)5- (i.e., 6,6-dimethyl-substituted normal-1,20-eicosylene). As described above, since the two R S s can together form a (C1-C 18 ) alkylene, examples of substituted (C1-C 50 ) alkylene 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.

[0103] The term "(C3-C 40 ) cycloalkylene" means an unsubstituted or substituted cyclic diradical (i.e., the radical is on a ring atom) of 3 to 40 carbon atoms. S

[0104] 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 ), and each R C , each R N , and each RP is unsubstituted (C1-C 18 ), or -H. The term "heterohydrocarbon" refers to a molecule or molecular backbone in which one or more carbon atoms are substituted with heteroatoms. The term "(C1-C 40 ) heterohydrocarbyl" means a heterohydrocarbon radical of 1 to 40 carbon atoms, and the term "(C1-C 40 ) heterohydrocarbylene" means a heterohydrocarbon diradical of 1 to 40 carbon atoms, each heterohydrocarbon having one or more heteroatoms. The radical of the heterohydrocarbyl is present on a carbon atom or a heteroatom, and the diradical of the heterohydrocarbyl can be present on (1) one or two carbon atoms, (2) one or two heteroatoms, or (3) one carbon atom and one heteroatom. Each (C1-C 50 ) heterohydrocarbyl and (C1-C 50 ) heterohydrocarbylene can be unsubstituted or substituted (by one or more R S ) and can be aromatic or non-aromatic, saturated or unsaturated, straight-chain or branched-chain, cyclic (including monocyclic and polycyclic, fused and non-fused polycyclic) or acyclic.

[0105] (C1-C 40 ) heterohydrocarbyl is unsubstituted or substituted (C1-C 40 ) heteroalkyl, (C1-C 40 ) hydrocarbyl-O-, (C1-C 40 ) hydrocarbyl-S-, (C1-C 40 ) hydrocarbyl-S(O)-, (C1-C 40 ) hydrocarbyl-S(O)2-, (C1-C 40 ) hydrocarbyl-Si(R C )2-, (C1-C 40 ) hydrocarbylN(R N )-, (C1-C 40 ) hydrocarbyl-P(R P )-, (C2-C 40 ) heterocycloalkyl, (C2-C 19 ) heterocycloalkyl-(C1-C 20 ) alkylene, (C3-C20 )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 may be.

[0106] “(C4-C 40 )heteroaryl” means an unsubstituted or substituted (by one or more R S ) monocyclic, bicyclic, or tricyclic heteroaromatic hydrocarbon radical having 4 to 40 total carbon atoms and 1 to 10 heteroatoms, where the monocyclic, bicyclic, or tricyclic radical contains 1, 2, or 3 rings respectively, and 2 or 3 rings are independently fused or unfused, and at least one of the 2 or 3 rings is a heteroaromatic ring. Other heteroaryl groups (e.g., generally, (C4-C 12 )heteroaryl such as (C x -C y )heteroaryl) have x to y carbon atoms (e.g., 4 to 12 carbon atoms, etc.) and are unsubstituted or substituted by one or more R SIt is defined in a manner similar to that replaced by. The monocyclic heteroaromatic hydrocarbon radical 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 ring heteroaromatic hydrocarbon radicals include pyrrol-1-yl, pyrrol-2-yl, furan-3-yl, thiophen-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 heteroatom can be N or P. Examples of 6-membered ring heteroaromatic hydrocarbon radicals include pyridin-2-yl, pyrimidin-2-yl, and pyrazin-2-yl. The bicyclic heteroaromatic hydrocarbon group can be a fused 5,6- or 6,6-ring system. Examples of fused 5,6-ring system bicyclic heteroaromatic hydrocarbon radicals include indol-1-yl and benzimidazol-1-yl. Examples of fused 6,6-ring system bicyclic heteroaromatic hydrocarbon groups include quinolin-2-yl and isoquinolin-1-yl. The tricyclic heteroaromatic hydrocarbon group can be a fused 5,6,5-, 5,6,6-, 6,5,6-, or 6,6,6-ring system. An example of a fused 5,6,5-ring system is 1,7-dihydropyrrolo[3,2-f]indol-1-yl. An example of a fused 5,6,6-ring system is 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.

[0107] The aforementioned heteroalkyl is (C1 to C 50It may be a saturated straight-chain or branched radical containing a carbon atom of or less and one or more heteroatoms. Similarly, heteroalkylene may be a saturated straight-chain or branched diradical containing 1 to 50 carbon atoms and one or two or more heteroatoms. The heteroatoms as defined above are Si(R C )3, Ge(R C )3, Si(R C )2, Ge(R C )2, P(R P )2, P(R P ), N(R N )2, N(R N ), N, O, OR C , S, SR C , S(O), and S(O)2 may be included, and each of the heteroalkyl group and the heteroalkylene group is unsubstituted or substituted by one or more R S .

[0108] Examples of unsubstituted (C2-C 40 ) hetero-cycloalkyl include unsubstituted (C2-C 20 ) hetero-cycloalkyl, unsubstituted (C2-C 10 ) hetero-cycloalkyl, aziridin-1-yl, oxetan-2-yl, tetrahydrofuran-3-yl, pyrrolidin-1-yl, tetrahydrothiophene-S,S-dioxide-2-yl, morpholin-4-yl, 1,4-dioxan-2-yl, hexahydroazepin-4-yl, 3-oxa-cyclooctyl, 5-thia-cyclononyl, and 2-aza-cyclodecyl.

[0109] The term "halogen atom" or "halogen" means a radical of a fluorine atom (F), a chlorine atom (Cl), a bromine atom (Br), or an iodine atom (I). The term "halide" means an anionic form of a halogen atom such as fluoride (F - ), chloride (Cl - ), bromide (Br - ), or iodide (I - ). The term "saturated" means lacking a carbon-carbon double bond, a carbon-carbon triple bond, and carbon-nitrogen, carbon-phosphorus, and carbon-silicon double bonds (in heteroatom-containing groups). When a saturated chemical group is substituted by one or more substituents R S one or more double and / or triple bonds may or may not be present optionally in the substituent R S . The term "unsaturated" means containing one or more carbon-carbon double bonds, carbon-carbon triple bonds, and carbon-nitrogen, carbon-phosphorus, and carbon-silicon double bonds (in heteroatom-containing groups), provided that any double bonds that may be present in the substituent R S or, if present, in the (hetero)aromatic ring are not included if they can be present in the substituent R

[0110] According to some embodiments, a catalyst system for producing a polyethylene composition comprises a metal-ligand complex according to formula (I).

[0111]

Chemical formula

[0112] In formula (I), M is a metal selected from titanium, zirconium, or hafnium, the metal is in a formal oxidation state of +2, +3, or +4, n is 0, 1, or 2, when n is 1, X is a monodentate ligand or a bidentate ligand, when n is 2, each X is a monodentate ligand, which may be the same or different, the metal-ligand complex is overall charge-neutral, each Z is independently selected from -O-, -S-, -N(R N ), or -P(R P ), L is a (C1-C 40 ) hydrocarbylene or a (C1-C 40 ) heterohydrocarbylene, the (C1-C 40 ) hydrocarbylene has a moiety (to which L is attached) containing a linker backbone of 1 to 10 carbon atoms connecting two Z groups in formula (I), or the (C1-C 40)The hetero hydrocarbylene has a moiety containing a linker backbone of 1 to 10 atoms connecting two Z groups in formula (I), (C1-C 40 )Each of the 1 to 10 atoms of the 1 to 10-atom linker backbone of the hetero hydrocarbylene is independently a carbon atom or a heteroatom, and each heteroatom is independently O, S, S(O), S(O)2, Si(R C )2, Ge(R C )2, P(R C ), or N(R C ), and each R C is independently (C1-C 30 )hydrocarbyl or (C1-C 30 )hetero hydrocarbyl, and R 1 and R 8 are independently -H, (C1-C 40 )hydrocarbyl, (C1-C 40 )hetero hydrocarbyl, -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 N ), (R N )2NC(O)-, halogen, and a radical having formula (II), formula (III), or formula (IV).

[0113]

Chemical formula

[0114] In formula (I), each of R 2~4 , R 5~7 , and R 9~16 is independently (C1-C 40 )hydrocarbyl, (C1-C 40 )heterohydrocarbyl, -Si(R C )3, -Ge(R C )3, -P(R P )2, -N(R N )2, -N=CHR C , -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 N )-, (R C )2NC(O)-, halogen, and -H.

[0115] In some embodiments, the polyethylene composition is formed using a first catalyst according to formula (I) in a first reactor and a different catalyst according to formula (I) in a second reactor.

[0116] In one exemplary embodiment where a double-loop reactor is used, the procatalyst used in the first loop is zirconium, [[2,2’’’-[bis[1-methylethyl]germylene]bis(methyleneoxy-κO)]bis[3’’,5,5’’-tris(1,1-dimethylethyl)-5’-octyl[1,1’:3’,1’’-terphenyl]-2’-olato-κO]](2-)]dimethyl, which has the chemical formula C 86 H 128 F2GeO4Zr and has the following structure (V):

[0117]

Chemical formula

[0118]

Chemical formula

[0119] Cocatalyst component The catalyst system containing the metal-ligand complex of formula (I) can be catalytically activated by any technique known in the art for activating metal-based catalysts for olefin polymerization reactions. For example, a system containing the metal-ligand complex of formula (I) can be catalytically activated by contacting the complex with an activating cocatalyst or by combining the complex with an activating cocatalyst. Suitable activating cocatalysts for use herein include alkylaluminum; polymeric or oligomeric aluminoxane (also known as aluminoxane); neutral Lewis acid; and non-polymeric, non-coordinating, ion-forming compounds (including the use of such compounds under oxidizing conditions). A preferred activating technique is bulk electrolysis. Combinations of one or more of the foregoing activating cocatalysts and techniques are also contemplated. The term "alkylaluminum" means monoalkylaluminum dihydride or monoalkylaluminum dihalide, dialkylaluminum hydride or dialkylaluminum halide, or trialkylaluminum. Examples of polymeric or oligomeric aluminoxanes include methylaluminoxane, triisobutylaluminum-modified methylaluminoxane, and isobutylaluminoxane.

[0120] Examples of Lewis acid activators (cocatalysts) include Group 13 metal compounds containing 1 to 3 (C1-C 20 ) hydrocarbyl substituents as described herein. In one embodiment, the Group 13 metal compound is a tri((C1-C 20 ) hydrocarbyl)-substituted-aluminum or tri((C1-C 20 ) hydrocarbyl)-boron compound. In other embodiments, the Group 13 metal compound is a tri(hydrocarbyl)-substituted aluminum, tri((C1-C 20 ) hydrocarbyl)-boron compound, tri((C1-C 10 ) alkyl)aluminum, tri((C6-C 18)They are aryl boron compounds and their halogenated (including perhalogenated) derivatives. In a further embodiment, the Group 13 metal compound is tris(fluorosubstituted phenyl)borane, tris(pentafluorophenyl)borane. In some embodiments, the activating cocatalyst is tris((C1-C 20 )hydrocarbyl borate (such as trityl tetrafluoroborate) or tri((C1-C 20 )hydrocarbyl)ammonium tetra((C1-C 20 )hydrocarbyl)borane (such as bis(octadecyl)methylammonium tetrakis(pentafluorophenyl)borane). As used herein, the term "ammonium" means a nitrogen cation that is ((C1-C 20 )hydrocarbyl)4N + , ((C1-C 20 )hydrocarbyl)3N(H) + , ((C1-C 20 )hydrocarbyl)2N(H)2 + , (C1-C 20 )hydrocarbylN(H)3 + , or N(H)4 + , and each (C1-C 20 )hydrocarbyl may be the same or different if more than one is present.

[0121] Examples of combinations of neutral Lewis acid activators (cocatalysts) include tri((C1-C4)alkyl)aluminum and tri((C6-C 18)Mixtures including an aryl boron compound, especially in combination with tris(pentafluorophenyl)borane, are included. Other embodiments 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. The molar ratio of (metal-ligand complex):(tris(pentafluoro-phenyl)borane):(aluminoxane) [e.g., (Group 4 metal-ligand complex):(tris(pentafluoro-phenyl)borane):(aluminoxane)] is from 1:1:1 to 1:10:30, and in other embodiments, from 1:1:1.5 to 1:5:10.

[0122] The catalyst system containing the metal-ligand complex of formula (I) can be activated by combination with one or more cocatalysts, such as cation-forming cocatalysts, strong Lewis acids, or combinations thereof, to form an active catalyst composition. Suitable activating cocatalysts include polymeric or oligomeric aluminoxanes, especially methylaluminoxane, and inert, compatible, non-coordinating, ion-forming compounds. Examples of suitable cocatalysts include modified methyl aluminoxane (MMAO), bis(hydrogenated tallow alkyl)methyl, tetrakis(pentafluorophenyl)borate(1 - )amine, and combinations thereof, but are not limited thereto.

[0123] In some embodiments, one or more of the foregoing activating cocatalysts are used in combination with each other. Particularly preferred combinations are tri((C1-C4)hydrocarbyl)aluminum, tri((C1-C4)hydrocarbyl)borane, or a mixture of ammonium borate and an oligomeric or polymeric alumoxane compound. The ratio of the total number of moles of one or more metal-ligand complexes of formula (I) to the total number of moles of one or more activating cocatalysts is from 1:10,000 to 100:1. In some embodiments, this ratio is at least 1:5000, in some other embodiments, at least 1:1000 and not more than 10:1, and in some other embodiments, not more than 1:1. When using alumoxane alone as the activating cocatalyst, the number of moles of alumoxane used is preferably at least 100 times the number of moles of the metal-ligand complex of formula (I). When using tris(pentafluorophenyl)borane alone as the activating cocatalyst, in some other embodiments, the number of moles of tris(pentafluorophenyl)borane used relative to the total number of moles of one or more metal-ligand complexes of formula (I) is from 0.5:1 to 10:1, 1:1 to 6:1, or 1:1 to 5:1. The remaining activating cocatalysts are generally used in a molar amount approximately equal to the total molar amount of one or more metal-ligand complexes of formula (I).

[0124] Nucleating agent The polyethylene-based composition used in the oriented multilayer film of the present invention may, in embodiments, further comprise one or more nucleating agents. In some embodiments, the polyethylene-based composition used in the oriented multilayer film of the present invention further comprises a nucleating agent that is a calcium salt of 1,2-cyclohexanedicarboxylic acid or sodium 4-[(4-chlorobenzoyl)amino]benzoate. These nucleating agents, when used in appropriate amounts and in combination with the polyethylene compositions described herein, in some embodiments provide one or more other improvements (e.g., stiffness, barrier, and / or optics) to the resulting film while providing a more uniform crystal distribution and crystal size in the polyethylene film, a more uniform melt behavior of the resulting polyethylene-based composition and the film formed from the polyethylene-based composition, and a larger processing window during the orientation of the film formed from the polyethylene-based composition.

[0125] However, in some embodiments, the polyethylene-based composition is substantially free of any nucleating agent. In other words, in such embodiments, the polyethylene-based composition can provide the desired properties in the oriented multilayer film of the present invention as further described herein. As used herein, in embodiments where the polyethylene-based composition is substantially free of any nucleating agent, the polyethylene-based composition contains from 0 to 19 ppm of all nucleating agents combined. In some embodiments, the polyethylene-based composition is free of any nucleating agent. In some embodiments, the polyethylene-based composition contains from 0 to less than 19 ppm of the calcium salt of 1,2-cyclohexanedicarboxylic acid or sodium 4-[(4-chlorobenzoyl)amino]benzoate. In some embodiments, the polyethylene-based composition is free of any calcium salt of 1,2-cyclohexanedicarboxylic acid or sodium 4-[(4-chlorobenzoyl)amino]benzoate.

[0126] In some embodiments, the nucleating agent is the calcium salt of 1,2 - cyclohexanedicarboxylic acid. In some embodiments, the nucleating agent is sodium 4 - [(4 - chlorobenzoyl)amino]benzoate. In some embodiments, the polyethylene - based composition comprises both the calcium salt of 1,2 - cyclohexanedicarboxylic acid and sodium 4 - [(4 - chlorobenzoyl)amino]benzoate.

[0127] Nucleating agents such as the calcium salt of 1,2 - cyclohexanedicarboxylic acid or sodium 4 - [(4 - chlorobenzoyl)amino]benzoate are heterogeneous nucleating agents. The amount and type of the heterogeneous nucleating agent are important for providing the desired performance. In some embodiments, the polyethylene - based composition comprises 20 - 5000 ppm of a heterogeneous nucleating agent in the form of the calcium salt of 1,2 - cyclohexanedicarboxylic acid or sodium 4 - [(4 - chlorobenzoyl)amino]benzoate, based on the total weight of the polyethylene - based composition. In some embodiments, the polyethylene - based composition comprises 20 - 2000 ppm of the calcium salt of 1,2 - cyclohexanedicarboxylic acid or sodium 4 - [(4 - chlorobenzoyl)amino]benzoate, based on the total weight of the polyethylene - based composition. In some embodiments, the polyethylene - based composition comprises 500 - 2000 ppm of the calcium salt of 1,2 - cyclohexanedicarboxylic acid or sodium 4 - [(4 - chlorobenzoyl)amino]benzoate, based on the total weight of the polyethylene - based composition.

[0128] In some embodiments, the heterogeneous nucleating agent can be provided together with fatty acid metal salts such as zinc stearate, zinc palmitate, and mixtures thereof. Based on how commercially available zinc stearate is prepared, since commercially available stearic acid often contains a significant amount of palmitic acid, some zinc palmitate may also be present. In some such embodiments, the polyethylene-based composition contains at least one of zinc stearate and zinc palmitate in an amount of 45 to 1000 ppm based on the total weight of the polyethylene-based composition. In some embodiments, the polyethylene-based composition contains zinc stearate and / or zinc palmitate in an amount of 50 to 700 ppm based on the total weight of the polyethylene-based composition. In some embodiments, the polyethylene-based composition contains zinc stearate and / or zinc palmitate in an amount of 85 to 600 ppm based on the total weight of the polyethylene-based composition.

[0129] A non-limiting example of the calcium salt of 1,2-cyclohexanedicarboxylic acid that can be used in embodiments of the present invention is Hyperform HPN-20E manufactured by Milliken Chemical of Spartanburg, South Carolina. Hyperform HPN-20E contains 60 to 70 weight percent of the calcium salt of 1,2-cyclohexanedicarboxylic acid and 30 to 40 weight percent of zinc stearate / zinc palmitate. In some embodiments, the polyethylene-based composition contains Hyperform HPN-20E in an amount of 20 to 5000 ppm based on the total weight of the polyethylene-based composition. In some embodiments, the polyethylene-based composition contains Hyperform HPN-20E in an amount of 20 to 2000 ppm based on the total weight of the polyethylene-based composition.

[0130] A non-limiting example of sodium 4-[(4-chlorobenzoyl)amino]benzoate that can be used in embodiments of the present invention is Hyperform HPN 210M manufactured by Milliken Chemical of Spartanburg, South Carolina.

[0131] In some embodiments, the calcium salt of 1,2 - cyclohexanedicarboxylic acid or sodium 4 - [(4 - chlorobenzoyl)amino]benzoate (and when also including fatty acid metal salts (e.g., zinc stearate and / or zinc palmitate)) can be provided as a masterbatch by blending it with a carrier resin prior to combining it with the polyethylene composition described herein. In some such embodiments, the carrier resin is polyethylene having a melt index (I2) of 1 to 12 g / 10 min. In some embodiments where the calcium salt of 1,2 - cyclohexanedicarboxylic acid and zinc stearate / zinc palmitate are provided as a masterbatch, the masterbatch contains 2 to 4 weight percent of the calcium salt of 1,2 - cyclohexanedicarboxylic acid and zinc stearate / zinc palmitate based on the total weight of the masterbatch. In one embodiment, the carrier resin is a narrow molecular weight distribution high - density polyethylene homopolymer having a density of 0.965 and a melt index (I2) of 8 to 9 g / 10 min. In some embodiments, the masterbatch can also contain other additives. Depending on the total amount of additives included, the masterbatch can contain 85 to 98 weight percent of the carrier resin based on the total weight of the masterbatch.

[0132] Other nucleating agents that can be used in some embodiments of the present invention include those disclosed in U.S. Patent Application Publication Nos. 2015 / 0087758, 2015 / 0087759, and 2015 / 0086736, which are incorporated herein by reference. In some embodiments, the polyethylene - based composition contains 20 to 5000 ppm of the nucleating agent as described above based on the total weight of the polyethylene - based composition. In some embodiments, the polyethylene - based composition contains 20 to 2000 ppm of the nucleating agent as described above based on the total weight of the polyethylene - based composition.

[0133] Silica In some embodiments, the polyethylene-based composition further comprises silica. Silica, when used in appropriate amounts in combination with the polyethylene compositions described herein, has been found to reduce the level of dusting in films formed from the polyethylene-based composition.

[0134] The amount of silica used in the polyethylene-based composition may be important for reducing the level of dusting when the polyethylene-based composition is incorporated into the surface layer of the film. In some embodiments, the polyethylene-based composition comprises 75 to 800 ppm of silica, based on the total weight of the polyethylene-based composition. In some embodiments, the polyethylene-based composition comprises 100 to 500 ppm of silica, based on the total weight of the polyethylene-based composition.

[0135] One non-limiting example of silica that can be used in embodiments of the present invention is Sylobloc 45, commercially available from Grace Davison Company.

[0136] In some embodiments, talc can be used in addition to or as an alternative to silica.

[0137] In some embodiments, silica can be provided as a masterbatch by blending it, prior to combination with the polyethylene compositions described herein, with a carrier resin, a calcium salt of 1,2-cyclohexanedicarboxylic acid or a similar nucleating agent, and zinc stearate / zinc palmitate. The masterbatch can be as described above in relation to the calcium salt of 1,2-cyclohexanedicarboxylic acid and zinc stearate / zinc palmitate. The amount of silica in the masterbatch can be based on the target silica for the entire polyethylene-based composition.

[0138] Oriented multilayer film The oriented (uniaxial or biaxial) polyethylene film of the present invention is a multilayer film. As previously shown, such a film comprises at least one layer comprising a polyethylene-based composition as described herein.

[0139] In some embodiments of the multilayer film of the present invention, the multilayer film can comprise the described polyethylene-based composition in two or more layers, and in other embodiments, such a polyethylene-based composition is provided in a single layer. The amount of the polyethylene-based composition for use in the film of the present invention can vary depending on a number of factors including, for example, other layers in the film, the desired properties of the film, the end use of the film, and the like.

[0140] The number of layers in the film can vary depending on a number of factors including, for example, the desired properties of the film, the desired thickness of the film, the content of other layers in the film, the end use of the film, the equipment available for manufacturing the film, and the like. For example, the multilayer film can further comprise other layers typically included in multilayer films depending on the application, which can include, for example, sealant layers, barrier layers, tie layers, structural layers, and the like. Multilayer inflation films or cast films can be composed of up to 2, 3, 4, 5, 6, 7, 8, 9, 10, or 11 layers in various embodiments.

[0141] The other layers within the multilayer film of the present invention can, in various embodiments, comprise polymers selected from the following: polyethylene-based compositions as described herein, LLDPE, VLDPE (very low density polyethylene), MDPE, LDPE, HDPE, HMWHDPE (high molecular weight HDPE), propylene-based polymers, polyolefin plastomers (POP), polyolefin elastomers (POE), olefin block copolymers (OBC), ethylene vinyl acetate, ethylene acrylic acid, ethylene methacrylic acid, ethylene methyl acrylate, ethylene ethyl acrylate, ethylene butyl acrylate, isobutylene, maleic anhydride grafted polyolefin, any of the aforementioned ionomers, or combinations thereof.

[0142] In some embodiments, in addition to the polyethylene-based composition, the oriented multilayer polyethylene film further comprises a second polyethylene composition, and the second polyethylene composition exhibits at least two local peaks in the comonomer distribution measured by crystallization elution fractionation, excluding the soluble fraction, and one of those peaks is between 40°C and 95°C. In some embodiments, the fraction forming the peak between 40°C and 95°C is at most 50 weight percent of the composition, as measured by crystallization elution fractionation. In some embodiments, the second polyethylene composition exhibits at least two local peaks in the comonomer distribution measured by crystallization elution fractionation, excluding the soluble fraction, and one of those peaks is between 40°C and 87°C. In some embodiments, the fraction forming the peak between 40°C and 87°C is at most 50 weight percent of the composition, as measured by crystallization elution fractionation. In some embodiments, the density of the second polyethylene composition is 0.928 to 0.940 g / cm 3 3. Examples of polyethylene compositions that can be used as the second polyethylene composition include the linear low density polyethylene resin described in U.S. Patent No. 10,363,700, which is incorporated herein by reference, and the following commercially available resins: DOWLEX™ 2750ST, ELITE™ 5940G, and ELITE™ 5960G, manufactured by The Dow Chemical Company. In embodiments where the film comprises such a second composition, the amount and location (i.e., layer) of the second composition to be used can vary depending on a number of factors, including, for example, other layers in the film, the desired properties of the film, the end use of the film, and the like. In some embodiments, the second composition is provided in a layer of the film having the polyethylene-based composition described herein.

[0143] In some embodiments, it should be understood that any of the layers within the film may further include one or more additives known to those skilled in the art, such as antioxidants, UV stabilizers, heat stabilizers, slip agents, anti-blocking agents, pigments or colorants, processing aids, crosslinking catalysts, flame retardants, fillers, and foaming agents (in addition to those described above for the polyethylene-based composition).

[0144] Due to being polyethylene-based, according to some embodiments of the present invention, the oriented multilayer polyethylene film can be incorporated into multilayer films and articles that are substantially or not completely, but mainly composed of polyethylene, in order to provide more easily recyclable films and articles. For example, a film mainly containing polyethylene has an improved recyclability profile in addition to other advantages that the use of such polymers can provide. For example, in some embodiments, the multilayer film is composed entirely of ethylene-based polymers except for additives. In some embodiments, the multilayer film may contain 90 wt% ethylene-based polymer, in some embodiments 95 wt% ethylene-based polymer, in some embodiments 99 wt% ethylene-based polymer, in some embodiments 99.9 wt% ethylene-based polymer, or in some embodiments 100 wt% ethylene-based polymer, based on the total weight of the multilayer film.

[0145] The multilayer film may have various thicknesses prior to orientation, depending on, for example, the number of layers, the intended use of the film, and other factors. In some embodiments, such a polyethylene film has a thickness of 320 - 3200 μm (typically 640 - 1920 μm) prior to orientation.

[0146] Prior to compounding, the polyethylene film can be formed using techniques known to those skilled in the art based on the teachings of this specification. For example, the film can be prepared as an inflation film (e.g., a water-quenched inflation film) or a cast film. For example, in the case of a multilayer polyethylene film, for the layers that can be coextruded, such layers can be coextruded as an inflation film or a cast film using techniques known to those skilled in the art based on the teachings of this specification.

[0147] In various embodiments, the polyethylene film can be uniaxially or biaxially oriented using techniques known to those skilled in the art.

[0148] In some embodiments where the film is bilayer oriented, the polyethylene film is biaxially oriented using a tenter frame sequential biaxial orientation process. Such techniques are generally known to those skilled in the art. In other embodiments, the polyethylene film can be biaxially oriented using other techniques known to those skilled in the art, such as a double bubble orientation process, based on the teachings of this specification. Generally, in a tenter frame sequential biaxial orientation process, the tenter frame is incorporated as part of a multilayer coextrusion line. After being extruded from a flat die, the film is cooled on a cooling roll and immersed in a water bath filled with water at room temperature. The cast film is then passed over a series of rollers having different rotational speeds to achieve stretching in the longitudinal direction. There are several pairs of rollers in the MD stretching segment of the production line, all of which are oil-heated. The pairs of rollers operate sequentially as preheating rollers, stretching rollers, and relaxation and annealing rollers. The temperature of each pair of rollers is controlled separately. After stretching in the longitudinal direction, the film web is passed through a tenter frame hot air oven having a heating zone to perform stretching in the transverse direction. The first several zones are for preheating, followed by stretching zones, and then a final zone for annealing.

[0149] In some embodiments, the polyethylene film can be oriented longitudinally at a draw ratio of from 2:1 to 9:1, or alternatively, at a draw ratio of from 2:1 to 6:1, or alternatively, at a draw ratio of from 4:1 to 6:1. In some embodiments, the polyethylene film can be oriented transversely at a draw ratio of from 2:1 to 11:1, or alternatively, at a draw ratio of from 2:1 to 9:1, or alternatively, at a draw ratio of from 6:1 to 9:1. In some embodiments, the polyethylene film is oriented longitudinally at a draw ratio of from 2:1 to 9:1 and transversely at a draw ratio of from 2:1 to 11:1. In some embodiments, the polyethylene film is oriented longitudinally at a draw ratio of from 2:1 to 6:1 and transversely at a draw ratio of from 2:1 to 9:1. In some embodiments, the polyethylene film is oriented longitudinally at a draw ratio of from 4:1 to 6:1 and transversely at a draw ratio of from 6:1 to 9:1.

[0150] In some embodiments, after orientation, the biaxially oriented film has a thickness of from 5 to 50 μm. In some embodiments, the biaxially oriented film has a thickness of from 15 to 40 μm.

[0151] In some embodiments, the biaxially oriented multilayer film of the present invention can exhibit more desirable properties, including, for example, haze and a 2% secant modulus in the longitudinal and transverse directions.

[0152] In some embodiments, the biaxially oriented multilayer film of the present invention exhibits a haze of less than 30%, in some embodiments less than 25%, in some embodiments less than 20%, in some embodiments less than 15%, or in some embodiments less than 10%. The biaxially oriented multilayer film of the present invention can exhibit a secant modulus of 2% in the longitudinal direction of at least 700 MPa, or in some embodiments at least 800 MPa, in some embodiments. The biaxially oriented multilayer film of the present invention exhibits a 2% secant modulus in the transverse direction of at least 900 MPa, in some embodiments at least 1000 MPa, or in some embodiments at least 1100 MPa. In some embodiments, the biaxially oriented film of the present invention exhibits a haze of less than 25%, a 2% secant modulus in the longitudinal direction of at least 700 MPa, and a 2% secant modulus in the transverse direction of at least 1000 MPa. In some embodiments, the biaxially oriented film of the present invention exhibits a haze of less than 10%, a 2% secant modulus in the longitudinal direction of at least 800 MPa, and a 2% secant modulus in the transverse direction of at least 1100 MPa.

[0153] In some embodiments, when the multilayer film is uniaxially oriented, the film is oriented only in the longitudinal direction. Various processing parameters are considered suitable for longitudinal stretching, as known to those skilled in the art based on the teachings herein. For example, the uniaxially oriented multilayer film can be oriented in the longitudinal direction at a draw ratio of greater than 1:1 and less than 8:1, or at a draw ratio of 4:1 to 8:1.

[0154] In some embodiments, after orientation, the longitudinally oriented film has a thickness of 5 to 50 μm. In some embodiments, the longitudinally oriented film has a thickness of 15 to 40 μm.

[0155] In some embodiments, for example depending on the end use, the oriented polyethylene film can be corona treated, plasma treated, or printed using techniques known to those skilled in the art. In some embodiments, the oriented multilayer film can be surface coated with aluminum, silicon oxide, aluminum oxide, or other metals known to those skilled in the art based on the teachings herein.

[0156] Laminate Embodiments of the present invention also include laminates incorporating an oriented multilayer polyethylene film. In some embodiments, the biaxially oriented multilayer polyethylene film according to embodiments of the present invention can be laminated to another film. In some embodiments, a uniaxially oriented (e.g., longitudinally oriented) multilayer polyethylene film according to embodiments of the present invention can be laminated to another film.

[0157] Other films in such embodiments include polyethylene sealant film, polyethylene terephthalate, polypropylene, or polyamide. The polyethylene sealant film can be a single-layer or multilayer film substantially formed from polyethylene (e.g., containing an ethylene-based polymer in excess of 90 weight percent, or an ethylene-based polymer in excess of 95 weight percent, or an ethylene-based property in excess of 99 weight percent), which can seal the laminate to another film, to another laminate, or to itself when heated as part of a laminate structure. Any polyethylene sealant film known to those skilled in the art can be used based on the teachings herein. When the other film includes polyethylene terephthalate, polypropylene, or polyamide, the entire film can be formed from polyethylene terephthalate, polypropylene, or polyamide, or the film can include at least one layer containing polyethylene terephthalate, polypropylene, or polyamide. Those skilled in the art can select a film containing polyethylene terephthalate, polypropylene, or polyamide for use in such embodiments based on the teachings herein.

[0158] The laminate according to an embodiment of the present invention can be formed using techniques known to those skilled in the art based on the teachings of this specification. For example, an oriented multilayer polyethylene film can be laminated to other films using an adhesive. Various adhesive compositions are considered suitable for the adhesive used in the laminate. These may include polyurethane, epoxy, acrylic, and the like. In one embodiment, the laminate may include an adhesive layer containing a polyurethane adhesive. The polyurethane adhesive can be solventless, aqueous, or solvent-based. Further, the polyurethane adhesive can be a two-component formulation. The weight or thickness of the adhesive layer can vary depending on many factors, including, for example, the desired thickness of the multilayer structure, the type of adhesive used, and other factors. In some embodiments, the adhesive layer is up to 5.0 grams / m 2 , or 1.0 to 4.0 g / m 2 , or 2.0 to 3.0 g / m 2 and is applied.

[0159] The laminate according to some embodiments of the present invention can also be formed by extrusion lamination.

[0160] Article Embodiments of the present invention also relate to articles such as packaging formed from (or incorporating) the oriented multilayer polyethylene film of the present invention. Such packaging can be formed from any of the films or laminates described herein.

[0161] Examples of such articles include flexible packaging materials, pouches, stand-up pouches, and ready-made packaging materials or ready-made pouches. In some embodiments, the oriented multilayer film or laminate of the present invention can be used for food packaging. Examples of foods that can be included in such packaging include meat, cheese, cereal, nuts, juice, sauce, and the like. Such packaging materials can be formed using techniques known to those skilled in the art based on the teachings of this specification and based on the specific use of the packaging material (e.g., type of food, amount of food, etc.).

[0162] Test method Unless otherwise indicated in this specification, the following analytical methods are used in the description of the embodiments of the present invention.

[0163] Melt index Melt index I2 (or I2) and I 10 (or I10) were measured according to ASTM D-1238 (Method B) at 190 °C with loads of 2.16 kg and 10 kg, respectively. These values are reported in g / 10 min.

[0164] Density Samples for density measurement were prepared according to ASTM D4703. The measurement was carried out according to ASTM D792, Method B within 1 hour of sample pressurization.

[0165] Conventional gel permeation chromatography (conventional GPC) The GPC-IR high-temperature chromatography system of PolymerChar (Valencia, Spain) is equipped with a 2-angle laser light scattering detector model 2040 manufactured by Precision Detectors (Amherst, Massachusetts), an IR5 infrared detector and a 4-capillary viscometer, both manufactured by PolymerChar. Data collection was carried out using PolymerChar's Instrument Control software and data collection interface. This system is equipped with an online solvent degassing device and a pump system manufactured by Agilent Technologies (Santa Clara, CA).

[0166] The injection temperature is controlled at 150 °C. The columns used are three 10-μm "Mixed-B" columns manufactured by Polymer Laboratories (Shropshire, UK). The solvent used is 1,2,4-trichlorobenzene. The sample is prepared at a concentration of "0.1 gram of polymer in 50 milliliters of solvent". The chromatography solvent and the sample preparation solvent each contained "200 ppm of butylated hydroxytoluene (BHT)". Both solvent sources were nitrogen sparged. The ethylene-based polymer sample is gently stirred at 160 °C for 3 hours. The injection volume is "200 microliters" and the flow rate is "1 milliliter / minute". The GPC column set is calibrated by running 21 "narrow molecular weight distribution" polystyrene standards. The molecular weight ("MW") of the standards ranges from 580 to 8,400,000 g / mol and the standards are contained in six "cocktail" mixtures. Each standard mixture has at least a 10-fold interval between individual molecular weights. The standard mixture is purchased from Polymer Laboratories. The polystyrene standards are prepared at "0.025 g in 50 mL of solvent" for molecular weights of 1,000,000 g / mol and above and at "0.050 g in 50 mL of solvent" for molecular weights below 1,000,000 g / mol.

[0167] The polystyrene standards are dissolved for 30 minutes with gentle stirring at 80 °C. The narrow standard mixtures are run first in the order in which the "highest molecular weight component" gradually decreases to minimize degradation. The polystyrene standard peak molecular weights are converted to polyethylene molecular weights using Equation 1 (as described in Williams and Ward, J. Polym. Sci., Polym. Letters, 6, 621 (1968)): M polyethylene = A × (M polystyrene) B (Equation 1), (where M is the molecular weight, A is equal to 0.4316, and B is equal to 1.0).

[0168] The number average molecular weight (Mn (conventional GPC)), weight average molecular weight (Mw (conventional GPC)), and z average molecular weight (Mz (conventional GPC)) are calculated according to the following equations 2 to 4.

[0169]

Number

[0170] In equations 2 to 4, RV is the column retention volume (linearly spaced) collected at "1 point per second", IR is the baseline-subtracted IR detector signal in volts from the IR5 measurement channel of the GPC instrument, and M PE is the polyethylene equivalent MW determined from equation 1. The data calculation is performed using PolymerChar's "GPC One software (version 2.013H)".

[0171] Creep zero shear viscosity measurement method The zero shear viscosity is obtained via a creep test performed at 190 °C using a parallel plate of "25 mm in diameter" with an AR G2 stress-controlled rheometer (TA Instruments; New Castle, Del). Before zeroing the mounting fixture, set the rheometer oven to the test temperature for at least 30 minutes. At that test temperature, insert the compression-molded sample disk between the plates and equilibrate for 5 minutes. Then, lower the upper plate 50 μm (instrument setting) above the desired test gap (1.5 mm). Trim and remove the excess material and lower the upper plate to the desired gap. The measurement is performed under a nitrogen purge at a flow rate of 5 L / min. Set the default creep time to 2 hours. Each sample is compression-molded into a circular plaque of "2 mm thick × 25 mm in diameter" at 177 °C for 5 minutes under a pressure of 10 MPa in air. Then, remove the sample from the compression machine, place it on a counter, and let it cool.

[0172] To ensure that the shear rate in the steady state is low enough to be in the Newtonian region, a constant low shear stress of 20 Pa is applied to all of the samples. The resulting steady-state shear rate is in the range of 10 -3 ~10 -4 s -1 for the samples in this test. The steady state is determined by taking a linear regression for all the data within the last 10% time window of the "log(J(t)) vs. log(t)" plot, where J(t) is the creep compliance and t is the creep time. If the slope of the linear regression is greater than 0.97, the creep test is stopped considering that the steady state has been reached. In all cases in this test, the slope meets the criterion within 1 hour. The steady-state shear rate is determined from the slope of the linear regression of all the data points within the last 10% time window of the "ε vs. t" (where ε is the strain) plot. The creep zero-shear viscosity is determined from the ratio of the applied stress to the steady-state shear rate.

[0173] To determine whether the sample is deteriorating during the creep test, a small amplitude oscillatory shear test is performed before and after the creep test on the same sample at 0.1 - 100 radians per second. The complex viscosity values of the two tests are compared. If the difference in the viscosity values at 0.1 radians per second is greater than 5%, the sample is considered to have deteriorated during the creep test and the results are discarded.

[0174] Zero-Shear Viscosity Ratio (ZSVR) The zero-shear viscosity ratio (ZSVR) is defined as the ratio of the zero-shear viscosity (ZSV) of a branched polyethylene material at the equivalent average molecular weight to the ZSV of a linear polyethylene material according to the following equation: ZSVR = η 0B / η 0L = η 0B / (2.29 -15 × Mwt 3.65 ) The ZSV value is obtained from a creep test at 190 °C via the method described above. Mwt is determined using gel permeation chromatography as described above. The correlation between the ZSV and the molecular weight of linear polyethylene was established based on a series of linear polyethylene reference samples. A lower ZSVR indicates a lower level of long-chain branching.

[0175] 13 Branch measurement using 13C NMR Sample preparation Samples are prepared by adding approximately 2.7 g of a 50 / 50 mixture of tetrachloroethane-d2 / orthodichlorobenzene containing 0.025 M Cr(AcAc)3 as a retarder to 0.20 - 0.30 g of the sample in a 10 mm NMR tube, product number 1001-7 from Norell. Oxygen is removed by purging the tube with N2 for 1 minute. The sample is dissolved and homogenized by heating the tube and its contents to 120 - 140 °C using a heating block and a vortex mixer. Each sample is visually inspected to confirm homogeneity. A fully mixed sample cannot be cooled before insertion into a heated NMR sample changer and / or NMR probe.

[0176] Data acquisition parameters Data is collected using a Bruker 600 MHz spectrometer equipped with a Bruker 10 mm multinuclear high-temperature CryoProbe. The data is acquired at a sample temperature of 120 °C using 1280 transients per data file, a pulse repetition delay of 7.8 seconds, a flip angle of 90 degrees, and inverse-gated decoupling. All measurements are performed on a non-rotating sample in lock mode. The sample is thermally equilibrated before data acquisition. 13 The 13C NMR chemical shift is referenced internally to the EEE triad at 30.0 ppm. The data is processed in the spectrum, appropriate peaks are integrated (to quantify branches), and then one or more peak integral values are used or averaged against total branches / 1000C. If no branches are detected, the detection limit of the spectrum is calculated using the integral value of peaks such as those due to chain ends and the signal-to-noise ratio.

[0177] 1 Measurement of Unsaturation Using 1H NMR The stock solution (3.26 g) is added to a polymer sample of 0.10 - 0.13 g in a 10 mm NMR tube. The above stock solution is a mixed solution of tetrachloroethane-d2 (TCE) and perchloroethylene (50:50, w:w), and contains 0.001 M Cr 3+ or a 100% TCE solution containing 0.001 M Cr 3+ The solution in the tube is purged with N2 for 5 minutes to reduce the amount of oxygen. The sample is dissolved at 120 - 140 °C while vortex mixing periodically. Each 1 1H NMR analysis is performed using a Bruker AVANCE 600 MHz spectrometer at 120 °C with a 10 mm cryoprobe.

[0178] Two experiments are carried out to measure the unsaturation, one is a control experiment and the other is a double pre-saturation experiment. In the control experiment, the data is processed with an exponential window function with a line broadening of 0.7 Hz. The signal from the residual 1 1H of TCE is set to 100, and the integral value (I 合計 ) in the range of about -0.5 - 3 ppm is used as the signal from the total polymer in the control experiment. The total number of carbon atoms NC in the polymer is calculated as follows by Equation 1A: NC = I 合計 / 2 (Equation 1A).

[0179] In the double pre-saturation experiment, the data is processed with an exponential window function with a line broadening of 0.7 Hz, and the baseline is corrected to about 7 - 4 ppm. The signal from the residual 1 1H of TCE is set to 100, and the corresponding integral values (I ビニレン , I 三置換 , I ビニル , and I ビニリデン) is integrated. The use of NMR spectroscopy to determine polyethylenic unsaturation is well known, see for example Busico, V., et al., Macromolecules, 2005, 38, 6988. The number of vinylene, trisubstituted, vinyl, and vinylidene unsaturated units is calculated as follows: N ビニレン =I ビニレン / 2 (formula 2A), N 三置換 =I 三置換 (Formula 3A), N ビニル =I ビニル / 2 (formula 4A), N ビニリデン =I ビニリデン / 2 (Equation 5A).

[0180] The unsaturated units per 1,000 total carbons, i.e., all polymer carbons including the main chain and branches, are calculated as follows: N ビニレン / 1,000C=(N ビニレン / NC) * 1,000 (Formula 6A), N 三置換 / 1,000C=(N 三置換 / NC) * 1000 (formula 7A), N ビニル / 1000C=(N ビニル / NCH2) * 1000 (formula 8A), N ビニリデン / 1000C=(N ビニリデン / NC) * 1000 (Formula 9A).

[0181] From the residual protons from TCE-d2 1 For H signal, the chemical shift standard is set at 6.0 ppm. A control is performed with a ZG pulse, NS=16, DS=2, AQ=1.82 s, D1=14 s (D1 is the relaxation delay). A double presaturation experiment is performed with a modified pulse sequence with O1P=1.354 ppm, O2P=0.960 ppm, NS=50, AQ=1.82 s, D1=1 s (D1 is the presaturation time), D13=13 s (D13 is the relaxation delay).

[0182] Crystallization elution fractionation method The crystallization elution fractionation method (CEF) is described in Monrabal et al, Macromol. Symp. 257, 71-79 (2007). The equipment is equipped with an IR-4 detector (such as those commercially available from PolymerChar, Spain) and a two-angle light scattering detector model 2040 (such as those commercially available from Precision Detectors). The IR-4 detector operates in a composition mode with two filters, C006 and B057. A 10 μm guard column of 50×4.6 mm (such as those commercially available from PolymerLabs) is installed in front of the IR-4 detector in the detector furnace. Ortho-dichlorobenzene (ODCB, 99% anhydrous grade) and 2,5-di-tert-butyl-4-methylphenol (BHT) (such as those commercially available from Sigma-Aldrich) are obtained. Silica gel 40 (particle size 0.2 - 0.5 mm) (such as those commercially available from EMD Chemicals) is also obtained. The silica gel is dried in a vacuum oven at 160 °C for about 2 hours before use. 800 mg of BHT and 5 g of silica gel are added to 2 L of ODCB. Here, the ODCB containing BHT and silica gel will simply be referred to as "ODCB". The ODBC is sparged with dry nitrogen (N2) for 1 hour before use. The dry nitrogen is obtained by passing nitrogen at less than 90 psig through CaCO3 and a 5 Å molecular sieve. Sample preparation is carried out using an autosampler at 4 mg / mL while shaking at 160 °C for 2 hours. The injection volume is 300 μL. The temperature profile of CEF is crystallization at 110 °C to 30 °C at 3 °C / min, thermal equilibrium at 30 °C for 5 minutes (including the soluble fraction elution time set at 2 minutes), and elution at 30 °C to 140 °C at 3 °C / min. The flow rate during crystallization is 0.052 mL / min. The flow rate during elution is 0.50 mL / min. The data is collected at 1 data point / second.

[0183] According to U.S. Patent Application Publication No. 2011 / 0015346 (A1), a 1 / 8-inch stainless steel tube is used to fill a CEF column with glass beads (such as those commercially available from MO-SCI Specialty Products) at 125 μm ± 6%. The internal liquid volume of the CEF column is 2.1 - 2.3 mL. Temperature calibration is performed by using a mixture of linear polyethylene 1475a (1.0 mg / mL) and eicosane (2 mg / mL) of NIST standard reference materials in ODCB. The calibration consists of the following four steps: (1) Calculating the delay volume, defined as the temperature offset, by subtracting 30.00 °C from the peak elution temperature of the measured eicosane. (2) Subtracting the temperature offset of the elution temperature from the CEF raw temperature data. Note that this temperature offset is a function of experimental conditions such as elution temperature and elution flow rate. (3) Creating a linear calibration line to convert the elution temperature over the range of 30.00 °C and 140.00 °C so that NIST linear polyethylene 1475a has a peak temperature of 101.00 °C and eicosane has a peak temperature of 30.00 °C. (4) Linearly extrapolating the elution temperature for the soluble fraction measured isothermally at 30 °C by using an elution heating rate of 3 °C / min. The reported elution peak temperature is obtained such that the observed comonomer content calibration curve matches that previously reported in U.S. Patent No. 8,372,931.

[0184] A linear baseline is calculated by selecting two data points, one before the polymer elutes (usually obtained at a temperature of 26 °C) and the other after the polymer elutes (usually obtained at 118 °C). For each data point, the detector signal is subtracted from the baseline before integration.

[0185] Turbidity Turbidity was measured using a Haze-gard from BYK Gardner in accordance with ASTM D1003.

[0186] Secant modulus of 2% The secant modulus at 2% strain is measured in the machine direction (MD) and cross direction (CD) using an Instron Universal testing machine according to ASTM D882-12, with a gauge length of 4 inches and a crosshead speed of 2 inches / minute.

[0187] Here, several embodiments of the present invention will be described in detail in the following examples.

Example

[0188] Polyethylene composition 1 The following are examples of polyethylene-based compositions that can be used in embodiments of the biaxially oriented multilayer polyethylene film of the present invention, as well as embodiments of the uniaxially oriented multilayer polyethylene film of the present invention. Embodiments of the polyethylene-based compositions described in the following examples utilize Polyethylene Composition 1 and Polyethylene Composition 2. Polyethylene Composition 1 is prepared according to the following process and based on the reaction conditions reported in Table 1.

[0189] Before introducing into the reaction environment, all raw materials (ethylene monomer) and process solvent (high-purity isoparaffin solvent with a narrow boiling range, Isopar-E) are purified by molecular sieving. Hydrogen is supplied pressurized as a high-purity grade and is not further purified. The monomer feed stream to the reactor is pressurized to a pressure higher than the reaction pressure by a mechanical compressor. The solvent feed is pressurized to a pressure higher than the reaction pressure by a pump. The individual catalyst components are manually batch diluted to the specified component concentrations using the purified solvent and pressurized to a pressure higher than the reaction pressure. All reaction feed streams are measured using mass flow meters and independently controlled by a valve control system automated by a computer.

[0190] The continuous solution polymerization reactor consists of two liquid-filled non-insulated isothermal circulation loop reactors similar to continuous stirred tank reactors (CSTRs) with heat removal. Independent control of all unused solvent, monomer, hydrogen, and catalyst component feeds to each reactor is possible. The entire unused feed stream (solvent, monomer, and hydrogen) to each reactor is temperature-controlled by passing the feed stream through a heat exchanger. The entire unused feed to each polymerization reactor is injected into the reactor at two positions per reactor with approximately equal reactor volumes between each injection location. The unused feed to the first reactor is typically controlled such that each injector receives half of the total mass flow rate of the unused feed. The unused feed to the second reactor in series is typically controlled to maintain half of the total ethylene mass flow rate near each injector, and since the unreacted ethylene from the first reactor enters the second reactor adjacent to the low-pressure unused feed, this injector typically has less than half of the total mass flow rate of the unused feed to the second reactor.

[0191] The catalyst / cocatalyst components for each injector are injected into the polymerization reactor through specially designed injection stingers. Each catalyst / cocatalyst component is injected separately at the same relative position within the reactor without pre-reactor contact time. The main catalyst component is computer-controlled to maintain individual reaction monomer conversion at a specific target value. The cocatalyst component is supplied based on a calculated specific molar ratio to the main catalyst component.

[0192] The catalyst used in the first reactor is zirconium, [[2,2’’’-[[bis[1-methylethyl]germylene]bis(methyleneoxy-κO)]bis[3’’,5,5’’-tris(1,1-dimethylethyl)-5’-octyl[1,1’:3’,1’’-terphenyl]-2’-olato-κO]](2-)]dimethyl-, which has the chemical formula C 86 H 128 F2GeO4Zr, and has the following structure (“Catalyst 1”):

[0193]

Chemical formula

[0194]

Chemical Structure

[0195] Immediately after the injection location of each reactor feed, the feed stream is mixed with the contents of a circulating polymerization reactor having static mixing elements. The contents of each reactor are passed through a heat exchanger that serves to remove most of the heat of reaction and continuously circulated at the coolant-side temperature that serves to maintain an isothermal reaction environment at a specific reaction temperature. The circulation around each reactor loop is provided by a pump.

[0196] The effluent from the first polymerization reactor (containing solvent, monomer, hydrogen, catalyst components, and molten polymer) exits the first reactor loop, passes through a control valve (which serves to maintain the pressure of the first reactor at a specific target value), and is injected into a second polymerization reactor of similar design. The final effluent from the second polymerization reactor enters a zone where the effluent is deactivated by the addition and reaction with a suitable reagent (water). At this same reactor outlet location, other additives are added for polymer stabilization. This final effluent stream passes through another set of static mixing elements to facilitate catalyst deactivation and additive dispersion.

[0197] Following the deactivation of the catalyst and the addition of the additive, the reactor effluent enters a devolatilization system where the polymer is removed from the non-polymer stream. The isolated polymer melt is pelletized and recovered. The non-polymer stream passes through various equipment that separates most of the ethylene removed from the system. Most of the solvent is recycled to the reactor after passing through the purification system. A small amount of solvent is purged from the process. Polyethylene composition 1 was stabilized with a small amount (ppm level) of stabilizer.

[0198] The polymerization conditions for polyethylene composition 1 are reported in Table 1. As seen in Table 1, cocatalyst 1 (bis(hydrogenated tallow alkyl)methyl, tetrakis(pentafluorophenyl)borate(1-)amine); and cocatalyst 2 (modified methylaluminoxane (MMAO)) are used as cocatalysts for catalyst 1 and catalyst 2, respectively.

[0199] Polyethylene composition 2 is prepared using the same catalyst system as polyethylene composition 1 and the same process under equivalent reaction conditions.

[0200] Additional properties of polyethylene composition 1 and polyethylene composition 2 were measured using the test methods described above and are reported in Table 2. The first polyethylene fraction refers to the polyethylene component from the first reactor, and the second polyethylene fraction refers to the polyethylene fraction from the second reactor.

[0201]

Table 1

[0202]

Table 2

[0203]

Number

[0204] Additional properties of polyethylene composition 1 and polyethylene composition 2 are evaluated and reported in Table 3.

[0205]

Table 3

[0206] Polyethylene composition 1 can be dry blended with the Hyperform HPN-20E nucleating agent (Milliken Chemical) provided in the masterbatch to target different final loadings of the HPN-20E nucleating agent (「HPN-20E」). An example of a masterbatch having HPN-20E contains 3 wt% HPN-20E, 1.5 wt% silica, 0.5 wt% hydrotalcite, 5 wt% antioxidant, and 90 wt% carrier resin. The carrier resin can be a narrow molecular weight distribution high density polyethylene homopolymer having a density of 0.965 g / cm 3 and a melt index (I2) of 8.0 g / 10 min. Hyperform HPN-20E contains about 66 wt% calcium salt of 1,2-cyclohexanedicarboxylic acid and about 34 wt% zinc stearate / zinc palmitate. In subsequent examples, this masterbatch formed with the Hyperform HPN-20E nucleating agent is referred to as 「nucleating agent masterbatch 1」.

[0207] The second masterbatch is also formed using Hyperform HPN-20E. The second masterbatch contains 10 weight percent HPN-20E and 90 weight percent XUS59910.08 (obtained from The Dow Chemical Company) as the carrier resin. In subsequent examples, this is referred to as "nucleating agent masterbatch 2".

[0208] As discussed below, some of the films of the present invention incorporate one or more nucleating agents, while others do not.

[0209] Example 1 In these examples, three-layer oriented polyethylene films are produced using a three-layer 2.1 meter wide pilot line from Biax. The films are produced using a three-layer die with a 3.1 mm die gap and are cast onto a cooling drum using an air knife finisher. The films are stretched longitudinally at a draw ratio of 5.75:1 through a series of heated differential speed rolls, followed by stretching transversely at a draw ratio of 7.5:1. Additional information regarding the production of these films is provided below.

[0210] A multilayer film having a width of 250 to 260 mm and a thickness of 0.8 to 1.2 mm is co-extruded through a three-layer die at a processing temperature of about 225°C to 260°C, cast onto a cooling drum whose surface temperature is controlled at 25°C to 50°C, and solidified into an unoriented film at a casting speed of about 4 to 6 meters per minute. The unoriented film is preheated longitudinally during stretching at about 75°C to 125°C and stretched longitudinally at a stretching ratio of about six times the original length at about 100°C to 145°C. The obtained stretched sheet is annealed at about 20°C to 110°C to reduce thermal shrinkage and obtain a uniaxially oriented film. The uniaxially oriented film is introduced into a width expander at a line speed of about 25 to 30 meters per minute, preheated at about 115°C to 145°C, stretched transversely at a stretching ratio of about eight times the original width at about 110°C to 145°C, and then heat-fixed or annealed at about 105°C to 135°C to reduce internal stress due to orientation, minimize thermal shrinkage of the final film, and obtain a biaxially oriented film with relatively high thermal stability. After biaxial orientation, the total thickness of the co-extruded film is nominally 18 μm, and its outer layers are each 3.5 μm. The biaxially oriented multilayer film may be wound in a roll. The longitudinal orientation relaxation rate may be 3 to 5%, and the transverse orientation relaxation rate may be 3 to 6%.

[0211] The film has the following structure A / B / C, which has thicknesses of 3.5 μm / 11 μm / 3.5 μm respectively. Layer B is the core layer, and layers A and C include both the skin layer and the sub-skin layer of a five-layer film stretching line. The final width is 1.1 m.

[0212] Films 1 to 4 of the present invention are shown in Table 3.

[0213]

Table 4

[0214] The haze, 2% secant modulus in the longitudinal direction, and 2% secant modulus in the transverse direction were measured, and the results are shown in Table 4.

[0215]

Table 5

[0216] Example 2 The following are examples of the oriented multilayer polyethylene films of the present invention that can be manufactured according to embodiments of the present invention.

[0217] In these examples, a three-layer, 2.1-meter-wide pilot line from Biaxs can be used to produce a three-layer oriented polyethylene film. The film can be produced using a three-layer die having a die gap of 3.1 mm and can be cast onto a cooling drum using an air knife pinna. The film can be stretched longitudinally at a draw ratio of 6:1 through a series of heated differential speed rolls and subsequently stretched transversely at a draw ratio of 8:1. Additional information regarding the production of these films is provided below.

[0218] A multilayer film having a width of 25 mm is co-extruded through a three-layer die at a processing temperature of about 225°C to 260°C, cast onto a cooling drum whose surface temperature can be controlled to 25°C to 50°C, and solidified into an unoriented film at a casting speed of about 4 to 6 meters per minute. The unoriented film is preheated longitudinally during stretching at about 75°C to 125°C and stretched longitudinally at about 100°C to 145°C with a stretch ratio of about six times the original length. The resulting stretched sheet is annealed at about 20°C to 110°C to reduce thermal shrinkage and obtain a uniaxially oriented film. The uniaxially oriented film is introduced into a width expander at a line speed of about 25 to 30 meters per minute, preheated at about 115°C to 145°C, stretched transversely at about 110°C to 145°C with a stretch ratio of about eight times the original width, and then heat-fixed or annealed at about 105°C to 135°C to reduce internal stress due to orientation, minimize thermal shrinkage of the final film, and obtain a relatively thermally stable biaxially oriented film. After biaxial orientation, the total thickness of the co-extruded film is nominally 18 μm, and its outer layers are each 3.5 μm. The biaxially oriented multilayer film may be wound in a roll. The longitudinal orientation relaxation rate may be 3 to 5%, and the transverse orientation relaxation rate may be 3 to 6%.

[0219] The film has the following structure A / B / C, which has thicknesses of 3.5 μm / 11 μm / 3.5 μm respectively. Layer B is the core layer, and layers A and C include both the skin layer and the sub-skin layer of the five-layer film stretching line. The final width is 1.1 m.

[0220] Films 5 to 13 of the present invention are shown in Table 5.

[0221]

Table 6

[0222] In some embodiments, after extrusion, rather than biaxially oriented, the film can be oriented only in the longitudinal direction to provide a uniaxially oriented film. For example, the film can be oriented in the longitudinal direction at the following temperatures using a MDO film stretching unit manufactured by Windmoeller & Hoelscher: preheating at 75°C to 115°C (preheating 1 at 75°C, preheating 2 at 115°C), stretching and shrinking at 125 to 145°C; annealing at 105°C; cooling at 45 to 75°C (e.g., 70°C). The longitudinal stretching ratio can be a stretching ratio of 4:1 to 20:1 (e.g., 4:1 to 16:1, or 4:1 to 12:1, or 4:1 to 10:1, or 4:1 to 9:1).

Claims

1. A biaxially oriented multilayer polyethylene film, comprising at least one layer, (1) a polyethylene-based composition, (a) a polyethylene composition of at least 97% by weight based on the total weight of the polyethylene-based composition, (i) A density in the range of 0.935 to 0.947 g / cm ３ and a melt index (I ２ ) of less than 0.1 g / 10 min, a first polyethylene fraction of 25 to 37 weight percent, (ii) a polyethylene composition comprising a second polyethylene fraction of 63 to 75 weight percent, and The polyethylene composition １３ has less than 0.10 branches per 1,000 carbon atoms when measured using C NMR, and the density of the polyethylene-based composition is at least 0.965 g / cm ３ and the melt index (I ２ ) of the polyethylene-based composition is 0.5 to 10 g / 10 min, a film.

2. The film according to claim 1, wherein the film is oriented in the longitudinal direction at a draw ratio of 2:1 to 9:1 and in the transverse direction at a draw ratio of 2:1 to 11:

1.

3. The film according to claim 1 or claim 2, wherein the polyethylene-based composition comprises at least 99% by weight of the polyethylene composition based on the total weight of the polyethylene-based composition and substantially does not contain any nucleating agent.

4. The film according to claim 1 or claim 2, wherein the polyethylene-based composition further comprises 20 to 5000 ppm of a nucleating agent based on the total weight of the polyethylene-based composition, and the nucleating agent comprises a calcium salt of 1,2-cyclohexanedicarboxylic acid or sodium 4-[(4-chlorobenzoyl)amino]benzoate.

5. The film according to any one of claims 1 to 4, further comprising a second polyethylene composition, wherein the second polyethylene composition exhibits at least two local peaks excluding the soluble fraction in the comonomer distribution measured by crystallization elution fractionation, and one of the peaks is at 40°C to 95°C.

6. The film according to claim 5, wherein the layer comprising the polyethylene-based composition further comprises the second polyethylene composition.

7. The overall density is 0.931 to 0.975 g / cm ３ The film according to any one of claims 1 to 6, which is such.

8. A uniaxially oriented multilayer polyethylene film, comprising at least one layer, (1) a polyethylene-based composition, (a) a polyethylene composition of at least 97% by weight based on the total weight of the polyethylene-based composition, (i) A density in the range of 0.935 to 0.947 g / cm ３ and a melt index (I ２ ) of less than 0.1 g / 10 min, a 25 to 37 weight percent first polyethylene fraction, and (ii) a polyethylene composition comprising a second polyethylene fraction of 63 to 75 weight percent, and The polyethylene composition １３ has less than 0.10 branches per 1,000 carbon atoms when measured using C NMR, and the density of the polyethylene-based composition is at least 0.965 g / cm ３ and the melt index (I ２ ) of the polyethylene-based composition is 0.5 to 10 g / 10 min, a film.

9. The film according to claim 8, wherein the polyethylene-based composition contains at least 99% by weight of the polyethylene composition based on the total weight of the polyethylene-based composition and substantially does not contain any nucleating agent.

10. A laminate comprising: a first film comprising a polyethylene sealant film, polyethylene terephthalate, polypropylene, or polyamide; and the oriented multilayer polyethylene film according to any one of claims 1 to 9, wherein the first film is laminated to the multilayer polyethylene film.

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