Oriented polyethylene film and an article containing the same

Abstract

The present invention relates to an oriented multilayer polyethylene film. In one embodiment, the biaxially oriented multilayer polyethylene film comprises at least one inner layer, the inner layer comprising: (1) a polyethylene-based composition, (a) at least 97% of the polyethylene-based composition having a viscosity of 0.926 g / cm, based on the total weight of the polyethylene-based composition; 3 ~0.970g / cm 3 and a melt index (I2) of 0.1 to 10 g / 10 min; and (b) 20 to 5000 ppm, based on the total weight of the polyethylene-based composition, of a sorbitol acetal derivative comprising a structure of formula (I), wherein R1 to R5 comprise the same or different moieties selected from hydrogen and C1 to C3 alkyl. [Case 1] JPEG2023506722000025.jpg98170

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.

[0002] Introduction section 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 from 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 that cannot be achieved 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 everything is polyethylene) to improve the recyclability profile. For example, in the case of a structure where everything is polyethylene, certain performance metrics (e.g., mechanical properties) need to be enhanced to maintain the performance levels expected of these structures when formed from different polymeric materials while improving recyclability. Therefore, 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 films are formed by cast extrusion and then oriented in the machine direction (MD) and subsequently in the transverse direction (TD) with a tenter frame. Alternatively, this process may 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 a new polyethylene-based composition having good processability into a biaxially oriented polyethylene film, as well as a new biaxially oriented polyethylene film having desired and / or improved properties. It would also be desirable to have a new polyethylene-based composition having good processability into a uniaxially oriented (e.g., longitudinally oriented) polyethylene film, as well as a new uniaxially oriented polyethylene film having desired and / or improved properties. SUMMARY OF THE INVENTION

[0005] The present invention provides a biaxially oriented multilayer polyethylene film, as well as 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, in some embodiments, can advantageously expand the processing window for stretching the film to provide a biaxially oriented polyethylene film. 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 optics (e.g., higher transparency and lower haze), improved barrier performance of metallized biaxially oriented polyethylene films, and, more generally, improved processability for larger and wider tenter frames, but are not limited thereto. The present invention also provides a uniaxially oriented (e.g., longitudinally oriented) multilayer polyethylene film, as well as 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 includes at least one inner layer, the inner layer being (1) a polyethylene-based composition, wherein (a) at least 97% based on the total weight of the polyethylene-based composition, 0.926 g / cm 3 ~0.970 g / cm3 one or more polyethylenes having a density of and (b) a sorbitol acetal derivative containing the structure of formula (I) in an amount of 20 to 5000 ppm based on the total weight of the polyethylene-based composition, the polyethylene-based composition comprising

Chemical formula

[0007] In another aspect, the present invention relates to articles such as food packaging. In one aspect, the article comprises any of the biaxially oriented multilayer polyethylene films disclosed herein.

[0008] In another aspect, the present invention relates to laminates and articles formed from such laminates. In some embodiments, the laminate comprises a first film comprising 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, the first film being laminated to the multilayer polyethylene film. In one aspect, the article comprises any of the laminates disclosed herein.

[0009] These and other embodiments are described in more detail in the mode for carrying out the invention.

Mode for Carrying Out the Invention

[0010] Unless there is no conflicting description, no indication implicitly from the context, or not customary 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 the present disclosure.

[0011] As used herein, the term "composition" refers to a mixture of materials that includes a composition, as well as reaction products and decomposition products formed from the materials of the composition.

[0012] "Polymer" means a polymeric compound prepared by polymerizing monomers, whether of the same kind or different kinds. Thus, the generic term polymer includes the term homopolymer as defined below, and the term interpolymer as defined below. Trace amounts of impurities (e.g., catalyst residues) may be incorporated in and / or within the polymer. The polymer can be a polymer mixture including a single polymer, a polymer blend, or a mixture of polymers formed in situ during polymerization.

[0013] As used herein, the term "homopolymer" refers to a polymer prepared from only one type of monomer, understanding that trace amounts of impurities can be incorporated into the polymer structure.

[0014] As used herein, the term "interpolymer" refers to a polymer prepared by the polymerization of at least two different monomers. Thus, the generic term interpolymer includes copolymers (used to refer to polymers prepared from two different monomers), and polymers prepared from three or more different monomers.

[0015] As used herein, the term "olefin-based polymer" or "polyolefin" refers to a polymer that includes (based on the weight of the polymer) a majority amount of an olefin monomer in polymerized form, such as ethylene or propylene, and optionally can include one or more comonomers.

[0016] As used herein, the term "ethylene / α-olefin interpolymer" refers to an interpolymer in polymeric form that contains units derived from more than half (> 50 mol%) of ethylene monomers and units derived from one or more remaining α-olefins. Typical α-olefins used in the formation of ethylene / α-olefin interpolymers are C3 - C 10 alkenes.

[0017] As used herein, the term "ethylene / α-olefin copolymer" refers to a copolymer in polymeric form that contains, as only two types of monomers, more than half (> 50 mol%) of ethylene monomers and an α-olefin.

[0018] As used herein, the term "α-olefin" refers to an alkene having a double bond at the first or alpha (α) position.

[0019] "Polyethylene" or "ethylene-based polymer" shall mean a polymer containing units derived from more than half (> 50 mol%) of ethylene monomers. This includes polyethylene homopolymers or copolymers (meaning units derived from two or more comonomers). General forms of polyethylene known in the art include low density polyethylene (LDPE), linear low density polyethylene (LLDPE), ultra 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 plastomers (POP) and ethylene-based elastomers (POE), medium density polyethylene (MDPE), and high density polyethylene (HDPE). These polyethylene materials are generally known in the art, but the following description may be useful in understanding some of the differences among these different polyethylene resins.

[0020] The term "LDPE" may also be referred to as "high pressure ethylene polymer" or "highly branched polyethylene", and is defined to mean that the polymer is homopolymerized or copolymerized, in part or completely, 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 to 0.935 g / cm 3 within the range of.

[0021] The term "LLDPE" includes both resins made using single site catalysts including, but not limited to, traditional Ziegler-Natta catalyst systems and chromium-based catalysts, as well as mono- or bis-cyclopentadienyl catalysts (typically referred to as metallocenes) and constrained geometry catalysts, phosphinimine and polyaryloxy ether catalysts (typically referred to as bisphenol phenoxy), and includes linear, substantially linear, or heterogeneous polyethylene copolymers or homopolymers. LLDPE contains shorter chain branches than LDPE and includes substantially linear ethylene polymers further defined in US Patent No. 5,272,236, US Patent No. 5,278,272, US Patent No. 5,582,923, and US Patent No. 5,733,155, uniformly branched linear ethylene polymer compositions such as those in US Patent No. 3,645,992, heterogeneously branched ethylene polymers prepared according to the process disclosed in US Patent No. 4,076,698, and / or blends thereof (such as those disclosed in US 3,914,342 or US 5,854,045). LLDPE can be made by gas phase, liquid phase, or slurry polymerization, or any combination thereof, using any type of reactor or reactor configuration known in the art.

[0022] The term "MDPE" refers to a density in the range of 0.926 to 0.935 g / cm 3refers to polyethylene having a density of. "MDPE" is typically produced using a chromium or Ziegler-Natta catalyst or a single-site catalyst including, but not limited to, a substituted mono- or bis-cyclopentadienyl catalyst (typically referred to as a metallocene), a constrained geometry catalyst, a phosphinimine catalyst, and a polyvalent aryloxy ether catalyst (typically referred to as bisphenol phenoxy), and typically has a molecular weight distribution ("MWD") greater than 2.5.

[0023] The term "HDPE" generally refers to polyethylene having a density of about 0.935 g / cm 3 to a maximum of about 0.980 g / cm 3 prepared using a Ziegler-Natta catalyst, a chromium catalyst, or a single-site catalyst including, but not limited to, a substituted mono- or bis-cyclopentadienyl catalyst (typically referred to as a metallocene), a constrained geometry catalyst, a phosphinimine catalyst, and a polyvalent aryloxy ether catalyst (typically referred to as bisphenol phenoxy).

[0024] The term "ULDPE" generally refers to polyethylene having a density of 0.855 - 0.912 g / cm 3 prepared using a Ziegler-Natta catalyst, a chromium catalyst, or a single-site catalyst including, but not limited to, a substituted mono- or bis-cyclopentadienyl catalyst (typically referred to as a metallocene), a constrained geometry catalyst, a phosphinimine catalyst, and a polyvalent aryloxy ether catalyst (typically referred to as bisphenol phenoxy). ULDPE includes, but is not limited to, polyethylene (ethylene-based) plastomers and polyethylene (ethylene-based) elastomers. Polyethylene (ethylene-based) elastomer plastomers generally have a density of 0.855 - 0.912 g / cm 3 having a density of.

[0025] The terms "blend", "polymer blend", etc. 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 configurations determined from transmission electron spectroscopy, light scattering, X-ray scattering, and any other methods known in the art. A blend is not a laminate, but one or more layers of a laminate may contain a blend. Such blends can be prepared as dry blends or formed in situ (e.g., in a reactor) as melt blends or using other techniques known to those skilled in the art.

[0026] All ranges disclosed herein include endpoints, and the endpoints are independently combinable with each other (e.g., "up to 25 wt%, or more specifically, 5 wt% to 20 wt%" includes the endpoints and all intermediate values of the range "5 wt% to 25 wt%", etc.). Further, ranges can be formed by combining the upper and lower limits described (e.g., "at least 1 or at least 2 weight percent" and "up to 10 or 5 weight percent" can be combined as the range "1 to 10 weight percent", or "1 to 5 weight percent", or "2 to 10 weight percent", or "2 to 5 weight percent").

[0027] The terms "comprising", "including", "having", and their derivatives are not intended to exclude the presence of any additional component, step, or procedure, 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 compounds or not, unless there is a conflicting description. In contrast, the term "consisting essentially of" excludes any other component, step, or procedure from the scope of any subsequent description, except for those that are not operationally essential. The term "consisting of" excludes any component, step, or procedure not specifically specified or enumerated.

[0028] The present invention generally relates to oriented multilayer polyethylene films. In some embodiments, such films are biaxially oriented. In some embodiments, such films are biaxially oriented using a tenter frame. In some embodiments, such films are uniaxially oriented in the longitudinal direction. The oriented multilayer polyethylene film utilizes a polyethylene-based composition in at least one inner 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.

[0029] In one aspect, the biaxially oriented multilayer polyethylene film includes at least one inner layer, which (1) is a polyethylene-based composition, (a) at least 97% based on the total weight of the polyethylene-based composition, of 0.926 g / cm 3 ~0.970 g / cm 3one or more polyethylenes having a density of and a melt index (I2) of 0.1 to 10 g / 10 min; (b) a sorbitol acetal derivative containing the structure of formula (I) in an amount of 20 to 5000 ppm based on the total weight of the polyethylene-based composition, and a polyethylene-based composition containing the same; [Chemical formula] wherein R1 to R5 contain the same or different moieties selected from hydrogen and C1-C3 alkyl. In some embodiments, the polyethylene-based composition contains 20 to 2000 ppm of the sorbitol acetal derivative based on the total weight of the polyethylene-based composition.

[0030] In some embodiments, the biaxially oriented film is oriented longitudinally at a draw ratio of 2:1 to 9:1 and laterally at a draw ratio of 2:1 to 11:1. In some embodiments, the biaxially oriented film is oriented longitudinally at a draw ratio of 2:1 to 6:1 and laterally at a draw ratio of 2:1 to 9:1. In some embodiments, the biaxially oriented film is oriented longitudinally at a draw ratio of 4:1 to 6:1 and laterally at a draw ratio of 6:1 to 9:1.

[0031] In some embodiments, the biaxially oriented multilayer polyethylene film further comprises a second polyethylene composition, the second polyethylene composition showing at least two local peaks in the comonomer distribution measured by crystallization elution fractionation, excluding the soluble fraction, and one of the peaks being between 40°C and 95°C. In some embodiments, the second polyethylene composition shows at least two local peaks in the comonomer distribution measured by crystallization elution fractionation, excluding the soluble fraction, and one of the peaks being between 40°C and 90°C. In some embodiments, the second polyethylene composition shows at least two local peaks in the comonomer distribution measured by crystallization elution fractionation, excluding the soluble fraction, and one of the peaks being between 40°C and 87°C. In some embodiments, the second polyethylene composition has a density of 0.928 to 0.940 g / cm3 It has a density. In some embodiments, the inner layer comprising a polyethylene-based composition further comprises a second polyethylene composition.

[0032] In some embodiments, the overall density of the biaxially oriented multilayer film is 0.931 to 0.975 g / cm 3 .

[0033] In some embodiments, the biaxially oriented multilayer film has a thickness of 5 to 50 microns.

[0034] The biaxially oriented multilayer film further comprises, in some embodiments, a layer comprising polyamide or ethylene vinyl alcohol.

[0035] In some embodiments, the biaxially oriented multilayer film further comprises an outer layer that is a sealant layer.

[0036] In some embodiments, the biaxially 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.

[0037] In another aspect, the present invention relates to an article such as food packaging. In one aspect, the article comprises any one of the biaxially oriented multilayer polyethylene films of the present invention disclosed herein.

[0038] 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 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 comprises any of the laminates disclosed herein.

[0039] In another aspect, the present invention is a uniaxially oriented multilayer polyethylene film, comprising at least one inner layer, the inner layer being (1) a polyethylene-based composition comprising (a) at least 97% based on the total weight of the polyethylene-based composition, one or more polyethylenes having a density of 0.926 g / cm 3 to 0.970 g / cm 3 and a melt index (I2) of 0.1 to 10 g / 10 min, and (b) 20 to 5000 ppm based on the total weight of the polyethylene-based composition, a sorbitol acetal derivative containing the structure of formula (I), and a polyethylene-based composition, [Chemical formula] wherein R1 to R5 are the same or different moieties selected from hydrogen and C1-C3 alkyl, and relates to a uniaxially oriented multilayer polyethylene film. In some embodiments, the film is oriented in the longitudinal direction.

[0040] In some embodiments, the uniaxially oriented film is oriented in the longitudinal direction at a draw ratio of 2:1 to 9:1. In some embodiments, the uniaxially oriented film is oriented in the longitudinal direction at a draw ratio of 2:1 to 6:1. In some embodiments, the uniaxially oriented film is oriented in the longitudinal direction at a draw ratio of 4:1 to 6:1.

[0041] 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, excluding the soluble fraction, in the comonomer distribution measured by crystallization elution fractionation, and one of the peaks is between 40°C and 95°C. In some embodiments, 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 between 40°C and 90°C. In some embodiments, 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 between 40°C and 87°C. In some embodiments, the second polyethylene composition has a density of 0.928 - 0.940 g / cm 3 ³. In some embodiments, the inner layer comprising the polyethylene-based composition further comprises the second polyethylene composition.

[0042] In some embodiments, the overall density of the uniaxially oriented multilayer film is 0.931 - 0.975 g / cm 3 ³.

[0043] In some embodiments, the uniaxially oriented multilayer film has a thickness of 5 - 50 microns.

[0044] In some embodiments, the uniaxially oriented multilayer film further comprises a layer containing polyamide or ethylene vinyl alcohol.

[0045] In some embodiments, the uniaxially oriented multilayer film further comprises an outer layer that is a sealant layer.

[0046] 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 includes Al, Zn, Au, Ag, Cu, Ni, Cr, Ge, Se, Ti, Sn, Si, Mg, or their oxides.

[0047] 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.

[0048] 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 one of the laminates disclosed herein.

[0049] Polyethylene used in polyethylene-based compositions As discussed above, the biaxially oriented (or uniaxially oriented) multilayer film of the present invention comprises at least one inner layer comprising a polyethylene-based composition having certain properties. The polyethylene-based composition comprises at least 97% based on the total weight of the polyethylene-based composition of one or more polyethylenes having a density of 0.926 g / cm 3 ~0.970 g / cm 3 and a melt index (I2) of 0.1 to 10 g / 10 min, and a sorbitol acetal derivative (discussed in more detail below).

[0050] In one or more embodiments described herein, the one or more polyethylenes have a density of 0.926 g / cm 3 ~0.970 g / cm 3 The density of 0.926 g / cm 3 ~0.970 g / cm 3All individual values and sub-ranges thereof are included in and disclosed in this specification. For example, in some embodiments, the polyethylene composition has a density of 0.926, 0.928, 0.930, 0.932, 0.934, 0.936, 0.938, 0.940, 0.942, 0.944, 0.946, 0.948, 0.950, 0.952, 0.954, 0.956, or 0.958 g / cm 3 from a lower limit of, and a density in the range of an upper limit of 0.940, 0.942, 0.944, 0.946, 0.948, 0.950, 0.952, 0.954, 0.956, 0.958, 0.960, 0.962, 0.964, 0.966, 0.968, or 0.970 g / cm 3 In various embodiments, the polyethylene composition has a density of 0.926 to 0.934 g / cm 3 0.926 to 0.940 g / cm 3 0.935 to 0.960 g / cm 3 0.940 to 0.955 g / cm 3 0.930 to 0.940 g / cm 3 0.960 to 0.970 g / cm 3 0.930 to 0.960 g / cm 3 or 0.952 to 0.958 g / cm 3 One or more polyethylenes can include low density polyethylene, linear low density polyethylene, medium density polyethylene, high density polyethylene, reinforced polyethylene, and / or other polyethylenes having a density from 0.926 g / cm

[0051] to 0.970 g / cm, as well as blends of any of the foregoing. 3 and 3 can include blends of any of the foregoing.

[0052] One or more polyethylenes used in the polyethylene-based composition may have a melt index (I2) of 0.1 g / 10 min to 10 g / 10 min. All individual values and sub-ranges from 0.1 g / 10 min to 10 g / 10 min are included and disclosed herein. For example, in some embodiments, the polyethylene composition has a melt index (I2) in the range from a lower limit of 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 2.0, 3.0, 4.0, or 5.0 g / 10 min to an upper limit of 0.9, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, or 10 g / 10 min. In various embodiments, the polyethylene composition may have a melt index (I2) of 0.1 g / 10 min to 0.5 g / 10 min, or 0.5 to 2.5 g / 10 min, or 0.5 g / 10 min to 2.0 g / 10 min, or 2.0 g / 10 min to 8.0 g / 10 min, or 1.0 g / 10 min to 4.0 g / 10 min.

[0053] In some embodiments of the present invention, various commercially available polyethylenes are contemplated for use as polyolefins. Examples of commercially available LDPE that can be used in embodiments of the present invention include those available from The Dow Chemical Company under the names DOW LDPE™ and AGILITY™. Examples of commercially available LLDPE that can be used in embodiments of the present invention include DOWLEX™ linear low density polyethylene commercially available from The Dow Chemical Company. Examples of commercially available HDPE that can be used in embodiments of the present invention include those commercially available from The Dow Chemical Company under the name Dow HOPE™. Those that can be used in some embodiments, 0.926 to 0.970 g / cm 3Examples of other commercially available polyethylenes having the density include those available from The Dow Chemical Company under the names ELITE™, ELITE™ AT, and INNATE™ (e.g., INNATE™ XUS 59910.08). Blends of such polyethylenes can also be used in the inner layer according to some embodiments.

[0054] In some embodiments, one or more polyethylenes used in the polyethylene-based composition are (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, and the polyethylene composition 13 has less than 0.10 branches per 1,000 carbon atoms as 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.

[0055] In some embodiments, the polyethylene-based composition has a melt index (I2) of 2.5 g / 10 min or less.

[0056] In some embodiments, the polyethylene composition has a first polyethylene fraction of 25 to 37 weight percent having a density in the range of 0.940 to 0.947 g / cm 3 and a second polyethylene fraction of 63 to 75 weight percent having a density of 0.970 g / cm 3 or greater.

[0057] The polyethylene composition can include a combination of two or more of the embodiments described herein.

[0058] 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 at most 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 can range from a lower limit of 0.965 or 0.967 g / cm 3 to an upper limit of 0.970, 0.972, 0.975, or 0.976 g / cm 3 .

[0059] 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) can range from 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 to 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) in the range 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.

[0060] In some embodiments, the polyethylene composition has a melt index ratio (I 10 / I2) of 10 or more. In some embodiments, the polyethylene composition has a melt index ratio (I 10 / I2) of at most 17. In some embodiments, the polyethylene composition has a melt index ratio (I 10 / I2) in the range of 10 to 17. In some embodiments, the polyethylene composition has a melt index ratio (I10 It has ( / I2).

[0061] The polyethylene composition has a low level of branching. In some embodiments, the polyethylene composition 13 When measured using 13C NMR, it has less than 0.10 branches per 1,000 carbon atoms. In some embodiments, the polyethylene composition 13 When measured using 13C NMR, it has less than 0.07 branches per 1,000 carbon atoms. In some embodiments, the polyethylene composition 13 When 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.

[0062] 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. In some embodiments, the polyethylene composition 1 When measured using 1H NMR, it has less than 20 non-vinyl unsaturations per 1 million carbon atoms.

[0063] Without wishing to be bound by theory, the combination of low levels of branching and low levels 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.

[0064] 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.

[0065] In one embodiment, the polyethylene composition has a ratio of weight-average molecular weight to number-average molecular weight (Mw / M n When expressed as (measured by conventional GPC), it has a molecular weight distribution in the range of 8.0 to 14.0. For example, the molecular weight distribution (M w / M n ) can be from a lower limit of 8.0, 8.5, 9.0, or 9.5 to 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.

[0066] In one embodiment, the polyethylene composition has a number average molecular weight (M n , determined by conventional GPC) in the range of 8,000 to 20,000 g / mol. For example, the number average molecular weight can be from a lower limit of 8,000, 9,000, 10,000, or 11,000 g / mol to an upper limit of 12,000, 13,000, 15,000, or 20,000 g / mol.

[0067] 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 can be from a lower limit of 100,000, 105,000, or 110,000 g / mol to an upper limit of 115,000, 120,000, or 124,000 g / mol.

[0068] 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, such as in the range of 350,000 to 600,000 g / mol. For example, the z-average molecular weight can be from a lower limit of 350,000, 375,000, 400,000, 405,000, or 410,000 g / mol to an upper limit of 420,000, 425,000, 450,000, 475,000, 500,000, 550,000, or 600,000 g / mol.

[0069] In one embodiment, the polyethylene composition has an Mw / Mn ratio (each determined by conventional GPC) greater than 3.0. In some embodiments, the polyethylene composition has an Mw / Mn ratio (each determined by conventional GPC) greater than 3.5. The Mw / Mn 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. z / Mn w In one embodiment, the polyethylene composition has a ZSVR of less than 2.0 and an Mw / Mn ratio (each determined by conventional GPC) greater than 3.0. In another embodiment, the polyethylene composition has a ZSVR of less than 2.0 and an Mw / Mn ratio (each determined by conventional GPC) greater than 3.5. z / Mn w The polyethylene composition preferably comprises an ethylene-based polymer formed in the absence of a comonomer. In some embodiments, the polyethylene composition comprises at least 99 wt% of an ethylene-based polymer formed in the absence of a comonomer. In some embodiments, the polyethylene composition comprises at least 99 wt% of a polymer comprising a majority (>99 mol%) of units derived from ethylene monomer. z / Mn w

[0070] In one embodiment, the polyethylene composition has a ZSVR of less than 2.0 and an Mw / Mn ratio (each determined by conventional GPC) greater than 3.0. In another embodiment, the polyethylene composition has a ZSVR of less than 2.0 and an Mw / Mn ratio (each determined by conventional GPC) greater than 3.5. z / Mn w In one embodiment, the polyethylene composition has a ZSVR of less than 2.0 and an Mw / Mn ratio (each determined by conventional GPC) greater than 3.0. In another embodiment, the polyethylene composition has a ZSVR of less than 2.0 and an Mw / Mn ratio (each determined by conventional GPC) greater than 3.5. z / Mn w

[0071] The polyethylene composition preferably comprises an ethylene-based polymer formed in the absence of a comonomer. In some embodiments, the polyethylene composition comprises at least 99 wt% of an ethylene-based polymer formed in the absence of a comonomer. In some embodiments, the polyethylene composition comprises at least 99 wt% of a polymer comprising a majority (>99 mol%) of units derived from ethylene monomer.

[0072] The polyethylene composition used in the polyethylene-based composition of the present invention comprises two fractions of polyethylene.

[0073] 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 ​​has a density. 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.

[0074] 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 3 or more. 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 10,000 g / 10 min or more. The second polyethylene fraction has a melt index (I2) of at least 100 g / 10 min and up to 10,000 g / 10 min. The second polyethylene fraction has a melt index (I2) of at least 100 g / 10 min and up to 1,000 g / 10 min.

[0075] 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.

[0076] The polyethylene composition comprises, based on the total weight of the polyethylene composition, 25 to 37 weight percent of a first polyethylene fraction and 63 to 75 weight percent of a second polyethylene fraction. In some embodiments, the polyethylene composition comprises, based on the total weight of the polyethylene composition, 30 to 37 weight percent of a first polyethylene fraction and 63 to 70 weight percent of a second polyethylene fraction.

[0077] The polyethylene-based composition comprises at least 97 weight % of a 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 a 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 a polyethylene composition, based on the total weight of the polyethylene-based composition.

[0078] The following discussion focuses on the preparation of polyethylene compositions for use in embodiments of the present invention.

[0079] Polymerization The polyethylene composition can be produced using any conventional polymerization process. Such conventional polymerization processes include slurry polymerization processes, solution polymerization processes using one or more conventional reactors, such as loop reactors, isothermal reactors, stirred tank reactors, simultaneous, continuous batch reactors, and / or any combination thereof, but are not limited thereto. The polyethylene composition can be produced, for example, by a solution phase polymerization process using one or more loop reactors, isothermal reactors, and combinations thereof.

[0080] Generally, the solution phase polymerization process is carried out 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.

[0081] The residence time in the solution phase polymerization process is 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 to one or more reactors. Exemplary solvents include, but are not limited to, isoparaffins. For example, such a solvent is commercially available under the name ISOPAR E from ExxonMobil Chemical Co., Houston, Texas. The 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 vapor-liquid separation drum, and then recycled to the polymerization system.

[0082] 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.

[0083] Catalyst system Certain embodiments of a catalyst system 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 this disclosure will be thorough and complete and will fully convey the scope of the subject matter to those skilled in the art.

[0084] The term "independently selected" means that R 1 , R 2 , R 3 , R 4 , and R 5 groups such as can be the same or different (e.g., R 1 , R 2 , R 3 , R 4 , and R 5 can all be substituted alkyl, or R 1 and R 2 can be substituted alkyl, R 3 can 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 in the art as corresponding to the R groups having that name. These definitions are intended to supplement and exemplify, not exclude, definitions known to those skilled in the art.

[0085] The term "pre-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 a pre-catalyst to convert the pre-catalyst into a catalytically active catalyst. As used herein, the terms "cocatalyst" and "activator" are interchangeable terms.

[0086] When used to describe a chemical group containing a particular carbon atom, "(C x ~C yA parenthesized expression having the form “(Cx to Cy)” 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 . A substituted version of a chemical group defined using the parenthesized “(C x ~C y )” may contain more than y carbon atoms depending on the identity of any group R S . For example, “(C1~C S )alkyl substituted by exactly one group R S where R S is phenyl (-C6H5)” may contain from 7 to 46 carbon atoms. Thus, generally, when a chemical group defined using the parenthesized “(C 40 ~C x )” is substituted by a substituent R y containing one or more carbon atoms, the minimum and maximum total number of carbon atoms of the chemical group is determined by adding to both x and y the sum of the carbon atoms derived from all substituents R S containing carbon atoms. S

[0087] 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 ). The term “over-substituted” means that all hydrogen atoms (H) bonded to a carbon atom or heteroatom of the corresponding unsubstituted compound or functional group are replaced by a substituent (e.g., R S ). The term “multi-substituted” means that at least two, but less than all, of the hydrogen atoms bonded to a carbon atom or heteroatom of the corresponding unsubstituted compound or functional group are replaced by a substituent.

[0088] The term "-H" means a hydrogen or hydrogen radical that is covalently bonded to another atom. The terms "hydrogen" and "-H" are interchangeable and, unless otherwise specified, mean the same thing.

[0089] The term "(C1-C 40 )hydrocarbyl" means a hydrocarbon radical having from 1 to 40 carbon atoms, and the term "(C1-C 40 )hydrocarbylene" means a hydrocarbon diradical having from 1 to 40 carbon atoms, each hydrocarbon radical and each hydrocarbon diradical being aromatic or non-aromatic, saturated or unsaturated, straight-chain or branched-chain, cyclic (monocyclic and polycyclic, including fused and non-fused polycyclic containing bicyclic and having 3 or more carbon atoms) or acyclic, unsubstituted or substituted by one or more R S .

[0090] 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 above (C1-C 40 )hydrocarbyl groups has a maximum of 20 carbon atoms (i.e., (C1-C 20 )hydrocarbyl), and in other embodiments, has a maximum of 12 carbon atoms.

[0091] The terms "(C1-C 40 )alkyl" and "(C1-C 18 )alkyl" each mean a saturated straight-chain or branched hydrocarbon group having from 1 to 40 carbon atoms or from 1 to 18 carbon atoms, the radical being unsubstituted or substituted by one or more RS. Examples of unsubstituted (C1-C 40 )alkyl are unsubstituted (C1-C20 ) Alkyl, unsubstituted (C1-C 10 ) Alkyl, unsubstituted (C1-C5) alkyl, methyl, ethyl, 1-propyl, 2-propyl, 1-butyl, 2-butyl, 2-methylpropyl, 1,1-dimethylethyl, 1-pentyl, 1-hexyl, 1-heptyl, 1-nonyl, and 1-decyl. Substituted (C1-C 40 ) Examples of alkyl are substituted (C1-C 20 ) Alkyl, substituted (C1-C 10 ) Alkyl, trifluoromethyl, and [C 45 Alkyl. The term "[C 45 Alkyl" (in square brackets) means that there are up to 45 carbon atoms in the radical including substituents. For example, one R S each of which is (C1-C5) alkyl, substituted (C 27 -C 40 ) alkyl. Each (C1-C5) alkyl can be methyl, trifluoromethyl, ethyl, 1-propyl, 1-methylethyl, or 1,1-dimethylethyl.

[0092] The term "(C6-C 40 ) aryl" means an unsubstituted or substituted (by one or more R S ) monocyclic, bicyclic, or tricyclic aromatic hydrocarbon radical having 6 to 40 carbon atoms, at least 6 to 14 of which are aromatic ring carbon atoms. The monocyclic, bicyclic, or tricyclic radical contains 1, 2, or 3 rings respectively, one ring is aromatic, the 2 or 3 rings are independently fused or unfused, and at least one of the 2 or 3 rings is aromatic. Examples of unsubstituted (C6-C 40 ) aryl are unsubstituted (C6-C 20 ) aryl, unsubstituted (C6-C 18)Aryl, 2-(C1-C5)alkyl-phenyl, 2,4-bis(C1-C5)alkyl-phenyl, phenyl, fluorenyl, tetrahydrofluorenyl, indacenyl, hexahydroindacenyl, indenyl, dihydroindenyl, naphthyl, tetrahydronaphthyl, and phenanthrene. Substituted (C6-C 40 )Examples of aryl are 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.

[0093] 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 as having x to y carbon atoms and being either unsubstituted or substituted with one or more R S . Examples of unsubstituted (C3-C 40 )cycloalkyl are unsubstituted (C3-C 20 )cycloalkyl, unsubstituted (C3-C 10 )cycloalkyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, and cyclodecyl. Examples of substituted (C3-C 40 )cycloalkyl are substituted (C3-C 20 )cycloalkyl, substituted (C3-C 10 )cycloalkyl, cyclopentanone-2-yl, and 1-fluorocyclohexyl.

[0094] (C1-C 40 )Examples of hydrocarbylene include unsubstituted or substituted (C6-C 40 )arylene, (C3-C 40)Cycloalkylene, and (C1-C 40 )alkylene (e.g., (C1-C 20 )alkylene) are included. 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 is separated by one, two, or more intervening carbon atoms (e.g., 1,3-diradical, 1,4-diradical, etc., respectively). Some diradicals include α,ω-diradicals. An α,ω-diradical is a diradical having the largest carbon skeleton spacing between the radical carbons. (C2-C 20 )Some examples of 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-). (C6-C 50 )Some examples of arylene α,ω-diradicals include phenyl-1,4-diyl, naphthalene-2,6-diyl, or naphthalene-3,7-diyl.

[0095] The term “(C1-C 40 )alkylene” means a saturated straight-chain or branched-chain diradical of 1 to 40 carbon atoms that is unsubstituted or substituted by one or more R S (i.e., the radical is not on a ring atom). Examples of unsubstituted (C1-C 50 )alkylene are unsubstituted (C1-C 20 )alkylene and include unsubstituted -CH2CH2-, -(CH2)3-, -(CH2)4-, -(CH2)5-, -(CH2)6-, -(CH2)7-, -(CH2)8-, -CH2C*HCH3, and -(CH2)4C*(H)CH3, where “C*” represents a carbon atom from which a hydrogen atom has been removed to form a secondary or tertiary alkyl radical. Examples of substituted (C1-C 50 )alkylene are substituted (C1-C 20 )alkylene, -CF2-, -C(O)-, and -(CH2) 14It is C(CH3)2(CH2)5- (that is, 6,6-dimethyl-substituted normal-1,20-eicosylene). As described above, the two Rs S together can form (C1-C 18 ) alkylene. Examples of substituted (C1-C 50 ) alkylene 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.

[0096] The term “(C3-C 40 ) cycloalkylene” means an unsubstituted or one or more Rs S substituted cyclic diradical (that is, the radical is on the ring atom) of 3 to 40 carbon atoms.

[0097] 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 R P is an unsubstituted (C1-C 18 ) hydrocarbyl or -H. The term “heterohydrocarbon” refers to a molecule or molecular skeleton 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 “(C1-C 40) The term "heterohydrocarbylene" means a heterohydrocarbon diradical having from 1 to 40 carbon atoms, each heterohydrocarbon having one or more heteroatoms. The radicals of the heterohydrocarbyl are present on carbon atoms or heteroatoms, and the diradicals of the heterohydrocarbyl may 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 may be unsubstituted or substituted (by one or more R S ), aromatic or non-aromatic, saturated or unsaturated, straight-chain or branched-chain, cyclic (including monocyclic and polycyclic, fused polycyclic and non-fused polycyclic) or acyclic.

[0098] (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 ) hydrocarbyl-N(R N )-, (C1-C 40 ) hydrocarbyl-P(R P )-, (C2-C 40 ) heterocycloalkyl, (C2-C 19 ) heterocycloalkyl-(C1-C 20 ) alkylene, (C3-C 20 ) cycloalkyl-(C1-C 19 ) heteroalkylene, (C2-C 19 ) heterocycloalkyl-(C1-C 20 ) heteroalkylene, (C1-C 40 ) heteroaryl, (C1-C 19 ) heteroaryl-(C1-C20 ) alkylene, (C6 - C 20 ) aryl-(C1 - C 19 ) heteroalkylene, or (C1 - C 19 ) heteroaryl-(C1 - C 20 ) heteroalkylene may also be used.

[0099] “(C4 - C 40 ) heteroaryl” means an unsubstituted or substituted (by one or more R S ) monocyclic, bicyclic, or tricyclic heteroaromatic hydrocarbon radical having a total of 4 to 40 carbon atoms and 1 to 10 heteroatoms, and 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 heteroaromatic. Other heteroaryl groups (e.g., (C4 - C 12 ) heteroaryl, etc., (C x - C y ) heteroaryl in general) have x to y carbon atoms (such as 4 to 12 carbon atoms) and are unsubstituted or substituted by one or more R SIt is defined in a similar manner as being 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 are pyridin-2-yl, pyrimidin-2-yl, and pyrazin-2-yl. The bicyclic heteroaromatic hydrocarbon radical 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 radicals include quinolin-2-yl and isoquinolin-1-yl. The tricyclic heteroaromatic hydrocarbon radical 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.

[0100] The aforementioned heteroalkyl is (C1-C 50) can be a saturated straight-chain or branched-chain radical containing a carbon atom or fewer carbon atoms than that and one or more heteroatoms. Similarly, heteroalkylene can be a saturated straight-chain or branched-chain diradical containing 1 to 50 carbon atoms and one or two or more heteroatoms. The heteroatoms as defined above include 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 .

[0101] Examples of unsubstituted (C2-C 40 ) heterocycloalkyl include unsubstituted (C2-C 20 ) heterocycloalkyl, unsubstituted (C2-C 10 ) heterocycloalkyl, 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.

[0102] 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 carbon-carbon double bonds, carbon-carbon triple bonds, and carbon-nitrogen, carbon-phosphorus, and carbon-silicon double bonds (in heteroatom-containing groups). When a saturated chemical group is substituted with one or more substituents R S one or more double and / or triple bonds may or may not be present in the substituents R S at will. 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 substituents R S or, if present, in the (hetero)aromatic ring are not included if they can be present in the substituents R

[0103] According to some embodiments, the catalyst system for producing the polyethylene composition comprises a metal-ligand complex according to formula (I).

Chemical formula

[0104] 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 and is the same or different, the metal-ligand complex is electrically neutral as a whole, 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 containing a linker backbone of 1 to 10 carbon atoms that connects two Z groups of formula (I) to which L is attached, or the (C1-C 40) The hetero hydrocarbylene has a moiety containing a 1- to 10-atom linker skeleton that connects two Z groups of formula (I), (C1-C 40 ) Each of the 1 to 10 atoms of the 1- to 10-atom linker skeleton of the hetero hydrocarbylene is independently a carbon atom or a hetero atom, and each hetero atom 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 the following formula (II), formula (III), or formula (IV) selected from the group consisting of.

Chemical formula

[0105] In formula (II), (III), and (IV), each of R 31~35 , R 41~48 , or R 51~59 is independently (C1-C 40 ) hydrocarbyl, (C1-C40 )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 N )2NC(O)-, halogen, or -H, provided that at least one of R 1 or R 8 is a radical having formula (II), formula (III), or formula (IV).

[0106] 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.

[0107] 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.

[0108] In an exemplary embodiment where a dual-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-, and has the chemical formula C 86 H 128 F2GeO4Zr and has the following structure.

Chemical formula

[0109] In such an embodiment, the procatalyst used in the second loop is zirconium, [[2,2’’’-[1,3-propanediylbis(oxy-κO)]bis[3-[2,7-bis(1,1-dimethylethyl)-9H-carbazol-9-yl]]-5’-(dimethyloctylsilyl)-3’-methyl-5-(1,1,3,3-tetramethylbutyl)[1,1]-biphenyl]-2-olato-κO]](2-)]dimethyl, and has the chemical formula C 107 H 154 N2O4Si2Zr and has the following structure.

Chemical formula

[0110] 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 in the present invention 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 aluminoxane or oligomeric aluminoxane include methylaluminoxane, triisobutylaluminum-modified methylaluminoxane, and isobutylaluminoxane.

[0111] The Lewis acid activator (cocatalyst) includes a Group 13 metal compound 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 a tri((C1-C 20 ) hydrocarbyl)-boron compound. In other embodiments, the Group 13 metal compound is a tri(hydrocarbyl)-substituted aluminum, a tri((C1-C 20 ) hydrocarbyl)-boron compound, a tri((C1-C 10 ) alkyl) aluminum, a tri((C6-C 18)They are aryl boron compounds and their halogenated (including perhalogenated) derivatives. In further embodiments, 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 (e.g., trityl tetrafluoroborate) or tri((C1-C 20 )hydrocarbyl)ammonium tetra((C1-C 20 )hydrocarbyl)borane (e.g., 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, when more than one is present, can be the same or different.

[0112] Combinations of neutral Lewis acid activators (cocatalysts) include tri((C1-C4)alkyl)aluminum and tri((C6-C 18) A mixture comprising an aryl boron compound, especially a combination with tris(pentafluorophenyl)borane, is mentioned. Other embodiments are combinations of such neutral Lewis acid mixtures with polymers or oligomeric aluminoxanes, and combinations of a single neutral Lewis acid, especially tris(pentafluorophenyl)borane, with polymers 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.

[0113] An active catalyst composition can be formed by activating a catalyst system comprising a metal-ligand complex of formula (I) and combining one or more cocatalysts, such as cation-forming cocatalysts, strong Lewis acids, or combinations thereof. Suitable activating cocatalysts include polymeric or oligomeric aluminoxanes, especially methylaluminoxane, and inert, compatible, non-coordinating, ion-forming compounds. Exemplary suitable cocatalysts include modified methylaluminoxane (MMAO), bis(hydrogenated tallow alkyl)methyl, tetrakis(pentafluorophenyl)borate(1 - ) amine, and combinations thereof, but are not limited thereto.

[0114] 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 aluminoxane 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 10:1 or less, and in still some other embodiments, 1:1 or less. When using an aluminoxane alone as the activating cocatalyst, preferably, the number of moles of the aluminoxane used is 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 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).

[0115] Sorbitol acetal derivative The polyethylene-based composition used in at least one inner layer of the oriented multilayer film of the present invention further comprises a sorbitol acetal derivative having the structure of formula (I),

Chemical formula

[0116] In some embodiments, R1 to R5 are hydrogen such that the sorbitol acetal derivative is 2,4-dibenzylidene sorbitol (“DBS”). In some embodiments, R1, R4, and R5 are hydrogen and R2 and R3 are methyl groups such that the sorbitol acetal derivative is 1,3:2,4-di-p-methyldibenzylidene-D-sorbitol (“MDBS”). In some embodiments, R1 to R4 are methyl groups and R5 is hydrogen such that the sorbitol acetal derivative is 1,3:2,4-bis(3,4-dimethylenebenzylidene)sorbitol (“DMDBS”). In some embodiments, R2, R3, and R5 are propyl groups (—CH2—CH2—CH3) and R1 and R4 are hydrogen such that the sorbitol acetal derivative is 1,2,3-trideoxy-4,6:5,7-bis-O-(4-propylphenylmethylene)nonitol (“TBPMN”). Additional information regarding such sorbitol acetal derivatives can be found, for example, in International Application PCT Publication No. WO2007 / 127067, and U.S. Patent No. 5,049,605.

[0117] When these sorbitol acetal derivatives are used in appropriate amounts and in combination with the polyethylene described herein, they are thought to provide 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, subsequently, as a result, a larger processing window during orientation of the film formed from the polyethylene-based composition, while also providing one or more other improvements (e.g., stiffness, barrier, and / or optical) to the resulting film.

[0118] The amount of the sorbitol acetal derivative of formula (I) used in the polyethylene-based composition is important in providing the desired performance. The polyethylene-based composition contains 20 to 5000 ppm of the sorbitol acetal derivative of formula (I) based on the total weight of the polyethylene-based composition. In some embodiments, the polyethylene-based composition contains 20 to 2000 ppm of the sorbitol acetal derivative of formula (I) based on the total weight of the polyethylene-based composition. In some embodiments, the polyethylene-based composition contains 250 to 5000 ppm of the sorbitol acetal derivative of formula (I) based on the total weight of the polyethylene-based composition.

[0119] Examples of the sorbitol acetal derivative of formula (I) that can be used in the polyethylene-based composition for embodiments of the present invention include those commercially available from Milliken Chemical under the name Millad, such as Millad 3988 (DMDBS) and Millad NX8000, and those commercially available from Roquette, such as Disorbene 3.

[0120] In some embodiments, the sorbitol acetal derivative of formula (I) can be provided as a masterbatch by blending it with a carrier resin before 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 sorbitol acetal derivative of formula (I) is provided as a masterbatch, the masterbatch contains 2 to 4 weight percent of the sorbitol acetal derivative of formula (I) 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.

[0121] Silica In some embodiments, the polyethylene composition further comprises silica. Silica has been found to reduce the level of dusting in films formed from polyethylene-based compositions when used in appropriate amounts in combination with the polyethylene compositions described herein.

[0122] The amount of silica used in the polyethylene-based composition can 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 contains 75 to 800 ppm of silica based on the total weight of the polyethylene-based composition. In some embodiments, the polyethylene-based composition contains 100 to 500 ppm of silica based on the total weight of the polyethylene-based composition.

[0123] 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.

[0124] In some embodiments, talc can be used in addition to or as an alternative to silica.

[0125] In some embodiments, silica can be provided as a masterbatch by blending it with a carrier resin, a calcium salt of 1,2-cyclohexanedicarboxylic acid (or a sodium salt of 4-[(4-chlorobenzoyl)amino]benzoic acid), and zinc stearate / zinc palmitate prior to combining it with the polyethylene composition described herein. The masterbatch can be as described above in relation to the calcium salt of 1,2-cyclohexanedicarboxylic acid (or the sodium salt of 4-[(4-chlorobenzoyl)amino]benzoic acid) and zinc stearate / zinc palmitate. The amount of silica in the masterbatch can be based on the target silica in the entire polyethylene-based composition.

[0126] Oriented multilayer film The oriented (uniaxial or biaxial) polyethylene films of the present invention are multilayer films. As previously shown, such films include at least one inner layer comprising the polyethylene-based composition described herein.

[0127] In some embodiments of the multilayer films of the present invention, the multilayer film can include 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 used for the films of the present invention can depend 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.

[0128] The number of layers in the film can depend 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 of the film, the end use of the film, the equipment available for manufacturing the film, etc. For example, a multilayer film can further include other layers typically included in a multilayer film depending on the application, which can include, for example, a sealant layer, a barrier layer, a tie layer, a structural layer, etc. Multilayer inflation films can be composed of up to 2, 3, 4, 5, 6, 7, 8, 9, 10, or 11 layers in various embodiments.

[0129] In various embodiments, the other layers within the multilayer film of the present invention include polymers selected from the following: polyethylene-based compositions 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, ionomers of any of the foregoing, or combinations thereof.

[0130] In some embodiments, in addition to the polyethylene-based composition, the oriented multilayer polyethylene film further includes a second polyethylene composition, and 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. In some embodiments, 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 87°C. In some embodiments, the density of the second polyethylene composition is 0.928 to 0.940 g / cm 3It is. 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 includes such a second composition, the amount and location (i.e., layer) of the second composition to be used can depend 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 one or more inner layers of the film having the polyethylene-based composition described herein.

[0131] It should be understood that in some embodiments, any of the layers within the film may further include one or more additives known to those of skill 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).

[0132] 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 mainly composed of polyethylene, if not substantially or completely, in order to provide more easily recyclable films and articles. For example, films mainly containing polyethylene have 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. Based on the total weight of the multilayer film, in some embodiments, the multilayer film may contain 90 wt% ethylene-based polymer, or in some embodiments 95 wt% ethylene-based polymer, or in some embodiments 99 wt% ethylene-based polymer, or in some embodiments 99.9 wt% ethylene-based polymer, or in some embodiments 100 wt% ethylene-based polymer.

[0133] Prior to orientation, the multilayer film can have various thicknesses depending on, for example, the number of layers, the intended use of the film, and other factors. Such polyethylene films, in some embodiments, have a thickness of 320 - 3200 microns (typically 640 - 1920 microns) prior to orientation.

[0134] Prior to biaxial orientation, the polyethylene film can be formed using techniques known to those skilled in the art based on the teachings herein. 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 herein.

[0135] In various embodiments, the polyethylene film can be uniaxially or biaxially oriented using techniques known to those skilled in the art.

[0136] In some embodiments where the film is biaxially oriented in two layers, 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 herein. Generally, in a tenter frame sequential biaxial orientation process, the tenter frame is incorporated as part of a multilayer coextrusion line. After extrusion from a flat die, the film is cooled on a cooling roll and immersed in a water bath filled with water at room temperature. Then, longitudinal stretching is achieved by passing the cast film through a series of rollers with different rotational speeds. There are several pairs of rollers in the MD stretching segment of the production line, and all of them 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 longitudinal stretching, the film web is passed through a tenter frame hot air oven with a heating zone to perform transverse stretching. The first several zones are for preheating, followed by stretching zones, and then the final zone for annealing.

[0137] In some embodiments, the polyethylene film can be longitudinally oriented at a draw ratio of 2:1 to 9:1, or alternatively, at a draw ratio of 2:1 to 6:1, or alternatively, at a draw ratio of 4:1 to 6:1. The polyethylene film can be transversely oriented at a draw ratio of 2:1 to 11:1, or alternatively, at a draw ratio of 2:1 to 9:1, or alternatively, at a draw ratio of 6:1 to 9:1 in some embodiments. In some embodiments, the polyethylene film is longitudinally oriented at a draw ratio of 2:1 to 9:1 and transversely oriented at a draw ratio of 2:1 to 11:1. The polyethylene film is longitudinally oriented at a draw ratio of 2:1 to 6:1 and transversely oriented at a draw ratio of 2:1 to 9:1 in some embodiments. In some embodiments, the polyethylene film is longitudinally oriented at a draw ratio of 4:1 to 6:1 and transversely oriented at a draw ratio of 6:1 to 9:1.

[0138] In some embodiments, after orientation, the biaxially oriented film has a thickness of 5 to 50 microns. In some embodiments, the biaxially oriented film has a thickness of 15 to 40 microns.

[0139] 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.

[0140] In some embodiments, after orientation, the longitudinally oriented film has a thickness of 5 to 50 microns. In some embodiments, the longitudinally oriented film has a thickness of 15 to 40 microns.

[0141] 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.

[0142] 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, the uniaxially oriented (e.g., longitudinally oriented) multilayer polyethylene film according to embodiments of the present invention can be laminated to another film.

[0143] Other films in such embodiments include polyethylene sealant films, polyethylene terephthalate, polypropylene, or polyamide. The polyethylene sealant film can be a single-layer or multi-layer film substantially formed from polyethylene (e.g., including an ethylene-based polymer of more than 90 weight percent, or an ethylene-based polymer of more than 95 weight percent, or an ethylene-based polymer of more than 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. Based on the teachings herein, any polyethylene sealant film known to those skilled in the art can be used. 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. One skilled in the art can select a film containing polyethylene terephthalate, polypropylene, or polyamide for use in such embodiments based on the teachings herein.

[0144] Laminates according to embodiments of the present invention can be formed using techniques known to those skilled in the art based on the teachings herein. For example, an oriented multi-layer polyethylene film can be laminated to another film using an adhesive. Various adhesive compositions are considered suitable for the adhesives used in the laminate. These can include polyurethanes, epoxies, acrylates, etc. In one embodiment, the laminate can include an adhesive layer containing a polyurethane adhesive. The polyurethane adhesive can be solventless, water-based, or solvent-based. Further, the polyurethane adhesive can be a two-component formulation. The weight or thickness of the adhesive layer can depend on many factors, including, for example, the desired thickness of the multi-layer 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 - 4.0 g / m 2 , or 2.0 - 3.0 g / m2 It is applied with

[0145] According to some embodiments of the present invention, the laminate can also be formed by extrusion lamination.

[0146] Article Embodiments of the present invention also relate to articles such as packaging that are formed from (or incorporate) the oriented multilayer polyethylene film of the present invention. Such packaging can be formed from any of the films or laminates described herein.

[0147] Examples of such articles include flexible packaging, pouches, stand-up pouches, and off-the-shelf packaging or pouches. In some embodiments, the 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 can be formed using techniques known to those skilled in the art based on the teachings herein and based on the specific use of the packaging (e.g., type of food, amount of food, etc.).

[0148] Test method Unless otherwise indicated herein, the following analytical methods are used in the description of aspects of the present invention.

[0149] 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. Those values are reported in units of g / 10 min.

[0150] Density Samples for density measurement were prepared according to ASTM D4703. The measurement was performed according to ASTM D792, Method B within 1 hour of sample pressurization.

[0151] Conventional Gel Permeation Chromatography (Conventional GPC) The GPC-IR high-temperature chromatography system from PolymerChar (Valencia, Spain) is equipped with a 2-angle laser light scattering detector model 2040 from Precision Detectors (Amherst, MA), both a PolymerChar IR5 infrared detector and a 4-capillary viscometer. Data collection was carried out using PolymerChar Instrument Control software and a data collection interface. This system is equipped with an online solvent degassing device and a pump system from Agilent Technologies (Santa Clara, CA).

[0152] The injection temperature is controlled at 150 degrees Celsius. The columns used are three 10-micron "Mixed-B" columns from 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 contain "200 ppm of butylated hydroxytoluene (BHT)". Both solvent sources are nitrogen sparged. The ethylene-based polymer sample is gently stirred at 160 degrees Celsius 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 is at least 10 apart between individual molecular weights. The standard mixtures are 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.

[0153] Dissolve the polystyrene standard at 80 °C with gentle stirring for 30 minutes. Run the narrow standard mixture first in the order of decreasing the highest molecular weight component to minimize degradation. Convert the polystyrene standard peak molecular weight to polyethylene molecular weight using Equation 1 (as described in Williams and Ward, J. Sci., Polym. Letters, 6, 621 (1968)).

[0154] Mpolyethylene = A × (Mpolystyrene) B Convert to polyethylene molecular weight using (Equation 1), where M is the molecular weight, A is equal to 0.4316, and B is equal to 1.0.

[0155] Calculate the number average molecular weight (Mn (conventional gpc)), weight average molecular weight (Mw - conventional gpc), and z average molecular weight (Mz (conventional gpc)) according to the following Equations 2 - 4.

Number

[0156] In Equations 2 - 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. Data calculations are performed using PolymerChar's "GPC One software (version 2.013H)".

[0157] Creep zero shear viscosity measurement method The zero shear viscosity is obtained via a creep test conducted on an AR G2 stress-controlled rheometer (TA Instruments, New Castle, Del) using parallel plates with a diameter of 25 mm at 190 °C. 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 to 50 μm (instrument setting) above the desired test gap (1.5 mm). Trim and remove excess material and lower the upper plate to the desired gap. Measurements are made under a nitrogen purge at a flow rate of 5 L / min. The default creep time is set to 2 hours. Each sample is compression-molded into a circular plaque with a thickness of 2 mm × diameter of 25 mm at 177 °C for 5 minutes under a pressure of 10 MPa in air. Then, remove the sample from the press, place it on a counter, and cool it.

[0158] To ensure that the steady-state shear rate is low enough to be in the Newtonian regime, apply a constant low shear stress of 20 Pa to all of the samples. The resulting steady-state shear rate ranges from 10 -3 ~10 -4 s -1 for the samples in this test. The steady state is determined by taking a linear regression for all data within the last 10% time window of a plot of log(J(t)) vs. log(t), 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, it is considered that the steady state has been reached, and then the creep test is stopped. 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 data points in the last 10% time window of a plot of “ε vs. t” (where ε is the strain). The creep zero shear viscosity is determined from the ratio of the applied stress to the steady-state shear rate.

[0159] To determine whether the sample is deteriorating during the creep test, a small amplitude oscillatory shear test is performed on the same sample at 0.1 to 100 radians per second before and after the creep test. 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.

[0160] 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 )

[0161] 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 of linear polyethylene and its molecular weight was established based on a series of linear polyethylene reference samples. A lower ZSVR indicates a lower level of long chain branching.

[0162] 13 Branching 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 Norell 1001-7 10 mm NMR tube. The tube is purged with N2 for 1 minute to remove oxygen. 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 ensure homogeneity. A fully mixed sample cannot be cooled before insertion into a heated NMR sample changer and / or NMR probe.

[0163] Data acquisition parameters The 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 s, 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 prior to data acquisition. 13 The 13C NMR chemical shifts are referenced internally to the EEE triad at 30.0 ppm. The data is processed into spectra, appropriate peaks are integrated (to quantify the branches), and then either one or more peak integration values are used, or averaged against total branches / 1000C. If no branches are detected, the detection limit of the spectrum is calculated using the integration values of peaks such as those due to chain ends and the signal-to-noise ratio.

[0164] 1 Unsaturation measurement 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 stock solution is either a mixture of tetrachloroethane-d2 (TCE) and perchloroethylene (50:50, w:w) with 0.001 M Cr 3+ or 100% TCE with 0.001 M Cr 3+ The solution in the tube is purged with N2 for 5 minutes to reduce the oxygen content. The sample is dissolved at 120 - 140 °C while vortex mixing periodically. Each 1 1H NMR analysis is performed on a Bruker AVANCE 600 MHz spectrometer at 120 °C using a 10 mm cryoprobe.

[0165] Two experiments are performed to measure the unsaturation, one is a control experiment and one is a double presaturation 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 integration value (I) in the range of approximately -0.5 to 3 ppm合計 ) is used as the signal from all polymers 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).

[0166] In the double pre-saturation experiment, the data is processed with an exponential window function having a line broadening of 0.7 Hz, and the baseline is corrected to about 7 - 4 ppm. The residual 1 signal from the H of TCE is set to 100, and the corresponding integrals for unsaturation (I ビニレン , I 三置換 , I ビニル , and I ビニリデン ) are integrated. It is known to use NMR spectroscopy to determine polyethylene unsaturation. See, for example, Busico, V., et al., Macromolecules, 2005, 38, 6988. The number of unsaturated units of vinylene, trisubstituted, vinyl, and vinylidene is calculated as follows. N ビニレン = I ビニレン / 2 (Equation 2A), N 三置換 = I 三置換 (Equation 3A), N ビニル = I ビニル / 2 (Equation 4A), N ビニリデン = I ビニリデン / 2 (Equation 5A)

[0167] The number of unsaturated units per 1,000 total carbons, i.e., all polymer carbons including the main chain and branches, is calculated as follows. N ビニレン / 1,000C = (N ビニレン / NC) * 1,000 (Equation 6A), N 三置換 / 1,000C = (N 三置換 / NC) * 1,000 (Equation 7A), N ビニル / 1,000C = (N ビニル / NCH2) * 1,000 (Equation 8A), N ビニリデン / 1,000C = (Nビニリデン / NC)*1,000 (Equation 9A).

[0168] From the residual protons from TCE-d2 1 Set the chemical shift reference to 6.0 ppm for the H signal. The control is executed with a ZG pulse, NS = 16, DS = 2, AQ = 1.82 s, D1 = 14 s (D1 is the relaxation delay). The double pre-saturation experiment is executed with O1P = 1.354 ppm, O2P = 0.960 ppm, NS = 50, AQ = 1.82 s, D1 = 1 s (D1 is the pre-saturation time), D13 = 13 s (D13 is the relaxation delay) with a modified pulse sequence.

[0169] Crystallization elution fractionation Crystallization elution fractionation (CEF) is described in Monrabal et al, Macromol. Symp. 257, 71-79 (2007). This instrument 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 compositional mode with two filters, C006 and B057. A 50×4.6 mm, 10 micron guard column (such as those commercially available from PolymerLabs) is installed in front of the IR-4 detector in the detector oven. Obtain orthodichlorobenzene (ODCB, 99% anhydrous grade) and 2,5-di-tert-butyl-4-methylphenol (BHT) (such as those commercially available from Sigma-Aldrich). Also obtain silica gel 40 (particle size 0.2 - 0.5 mm) (such as those commercially available from EMD Chemicals). The silica gel is dried in a vacuum oven at 160 °C for approximately 2 hours before use. Add 800 milligrams of BHT and 5 grams of silica gel to 2 liters of ODCB. Here, "ODCB containing BHT and silica gel" is 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 3 °C / min from 110 °C to 30 °C, thermal equilibrium at 30 °C for 5 minutes (including the soluble fraction elution time set to 2 minutes), and elution at 3 °C / min from 30 °C to 140 °C. The flow rate during crystallization is 0.052 ml / min. The flow rate during elution is 0.50 ml / min. Data is collected at 1 data point / second.

[0170] Using a 1 / 8-inch stainless steel tube according to US2011 / 0015346(A1), fill the 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 NIST standard reference materials, linear polyethylene 1475a (1.0 mg / ml) and eicosane (2 mg / ml) in ODCB. The calibration consists of four steps: (1) Calculating the delay volume defined as the temperature offset obtained by subtracting 30.00 °C from the measured peak elution temperature of 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 calibration straight line by converting the elution temperature over the range of 30.00 °C to 140.00 °C such that the NIST linear polyethylene 1475a has a peak temperature of 101.00 °C and eicosane has a peak temperature of 30.00 °C, and (4) Linearly extrapolating the elution temperature by using an elution heating rate of 3 °C / min for the soluble fraction measured at an isotherm of 30 °C. Obtain the reported elution peak temperature such that the observed comonomer content calibration curve matches that previously reported in US8,372,931.

[0171] Calculate the linear baseline by selecting two data points: one before the polymer elutes (usually at a temperature of 26 °C), and the other after the polymer elutes (usually at 118 °C). For each data point, subtract the baseline from the detector signal before integration.

[0172] Secant modulus (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.

[0173] Haze Haze is measured in accordance with ASTM D 1003. For the test, Hazegard Plus (BYK-Gardner USA, Columbia, MD) was used. For each test, five samples were examined and the average was reported. The sample size was “6 inches × 6 inches”.

[0174] Gloss Gloss is measured in accordance with ASTM D2457 using a BYK Gardner Glossmeter Microgloss 45°.

[0175] Here, some embodiments of the present invention will be described in detail in the following examples.

Example

[0176] 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 was prepared according to the following process and based on the reaction conditions reported in Table 1.

[0177] 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 with molecular sieves. Hydrogen is supplied pressurized as a high-purity grade and is not further purified. The reactor monomer feed stream is pressurized to a pressure higher than the reaction pressure via a mechanical compressor. The solvent feed is pressurized to a pressure higher than the reaction pressure by a pump. Each catalyst component is manually batch diluted to a specified component concentration 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.

[0178] 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 fresh 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 approximately 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 unused feed mass flow rate to the second reactor.

[0179] 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 a contact time prior to the reactor. The main catalyst component is computer-controlled to maintain the 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.

[0180] 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-, with the chemical formula C 86 H 128 F2GeO4Zr and has the following structure (“Catalyst 1”).

Chemical formula

[0181] The catalyst used in the second reactor is dimethyl [[2,2’’’-[1,3-propanediylbis(oxy-κO)]bis[3-[2,7-bis(1,1-dimethylethyl)-9H-carbazol-9-yl]]-5’-(dimethyloctylsilyl)-3’-methyl-5-(1,1,3,3-tetramethylbutyl)[1,1]-biphenyl]-2-olato-κO]](2-)]zirconium, with the chemical formula C 107 H 154 N2O4Si2Zr and has the following structure (“Catalyst 2”).

Chemical formula

[0182] 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.

[0183] 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.

[0184] Following catalyst deactivation and additive addition, the reactor effluent enters a devolatilization system where the polymer is removed from the non-polymer stream. The isolated polymer melt is pelletized and collected. 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) of stabilizer.

[0185] 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.

[0186] Polyethylene composition 2 is prepared using the same catalyst system as polyethylene composition 1 and the same process under equivalent reaction conditions.

[0187] Additional properties of polyethylene composition 1 and polyethylene composition 2 are measured using the test methods described above and 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.

Table 1

Table 2

[0188] The density of the first polyethylene fraction of polyethylene composition 1, the overall polyethylene composition 1, and the overall polyethylene composition 2 is measured as described in the test methods section. The density of the first polyethylene fraction of polyethylene composition 2 is the target value. The density of the second polyethylene fraction is calculated using the following blending rule.

Equation

[0189] The additional properties of polyethylene composition 1 and polyethylene composition 2 are evaluated and reported in Table 3. [Table 3]

[0190] Polyethylene composition 1 can be dry blended with the sorbitol acetal derivative of formula (I) provided in the masterbatch (e.g., Millad NX 8000 manufactured by Milliken Chemical) to target different final loadings of the sorbitol acetal derivative. An example of a masterbatch containing Millad NX 8000 includes 5 weight percent Millad NX 8000 and 95 weight percent carrier resin (e.g., INNATE™ XUS 59910.08).

[0191] Example 1 Using the resins in Table 1 below, single-layer films of Examples 1 to 3 are produced. [Table 4]

[0192] Comparative Film A is a single-layer film composed entirely of polyethylene 1. Film 1 of the present invention is a single-layer film composed of 96 weight percent polyethylene 1 and 4 weight percent sorbitol acetal derivative masterbatch.

[0193] Comparative Film A and Film 1 of the present invention are produced using a Dr. Collin cast film extruder under the following conditions. Throughput rate = approximately 9 kg / h Melting temperature = 180 °C Cast roll speed = 94 rpm Cooling roll temperature = 28 °C Gap = 1.5 inches Die gap = 55 mils.

[0194] The film has a nominal thickness of 50 mils.

[0195] The film is then drawn on an Accupull biaxial film stretcher (Inventure Laboratories, Inc.) under the following conditions: Specimen size = 48 mm x 48 mm (fixed) Temperature of upper and lower plates = 115 °C Immersion time = 20 - 40 seconds Heating time = 90 - 95 seconds (+ / - 5 °C) Drawing speed = 92 mm / second (or a strain rate of approximately 200%) Drawing temperature = approximately 115 - 120 °C.

[0196] The drawability of Comparative Film A and Film 1 of the present invention is evaluated at different temperatures and different draw ratios. The results are shown in Tables 2 and 3.

Table 5

Table 6

[0197] The region indicated by "+" indicates a region of good drawability. The region indicated by "-" means that the film is heated and tears during drawing. The region indicated by "X" indicates overheating and the film melts during heating. Comparing Table 2 and Table 3, the drawability window expands by approximately 2 °C (centered around approximately 123 °C) - 6 °C (centered around approximately 121 °C) due to the addition of the sorbitol acetal derivative.

[0198] In addition, several properties are measured to evaluate the effect of the sorbitol acetal derivative on performance. The 2% secant modulus in the longitudinal direction, total haze, and gloss are the measurement items. Table 4 shows the results.

Table 7

[0199] Example 2 In this example, a three-layer biaxially oriented polyethylene film is produced using a Bruckner V.5100-510 pilot film stretch line with a final film width of 1.1 meters. The film is produced via coextrusion using a five-layer die having a die gap of 3.1 mm and casting onto a cooling drum using a high-pressure air knife. The film is stretched longitudinally at a draw ratio of 4.6:1 through a series of heated differential speed rolls and subsequently stretched transversely at a draw ratio of 6.1:1. Additional information regarding the production of these films is provided below.

[0200] A multilayer coextrusion film having a width of 25 mm is coextruded through a die at a processing temperature of about 225°C to 260°C and cast onto a cooling drum with a surface temperature controlled to 30°C to 40°C to solidify an unoriented laminate sheet at a casting speed of about 4 to 10 meters per minute. The unoriented film is preheated for longitudinal orientation at about 90°C to 120°C and stretched longitudinally at about 95°C to 110°C at a draw ratio of about 4.6 times the original length. The resulting stretched film is annealed at about 20°C to 95°C to reduce thermal shrinkage and obtain a uniaxially oriented laminate film. The uniaxially oriented film is introduced into a tenter at a line speed of about 25 to 50 meters per minute, preheated at about 130°C to 145°C, stretched transversely at about 125°C to 130°C at a draw ratio of about 6.1 times the original width, and then heat set or annealed at about 105°C to 125°C to reduce internal stress due to orientation and minimize the thermal shrinkage of the final film, obtaining a relatively thermally stable biaxially oriented film. After biaxial orientation, the total thickness of the coextrusion film is nominally 20 microns. The outer layers are each 5 micrometers. The film is heat set or annealed in the final zone of the tenter oven to reduce internal stress and minimize the thermal shrinkage of the film, maintaining a dimensionally stable biaxially oriented film. The side of skin layer A on the core layer facing the seal skin layer is treated via a corona discharge treatment method after orientation. The biaxially oriented multilayer film is wound in a roll and is being wound.

[0201] The film has the following structure A / B / C, which has thicknesses of 5 microns / 10 microns / 5 microns respectively. Layer B is the core layer, and layers A and C include both the skin layer and the sub-skin layer of a 5-layer film stretching line. The final width is 0.8 m. Optionally, in order to improve processability, layer C may contain 2 - 4% anti-adhesive agent and slip masterbatch.

[0202] Comparative films B and C and film 2 of the present invention are shown in Table 5 along with the characteristic evaluation of processability.

Table 8

[0203] Example 3 The following are additional examples of the oriented multilayer polyethylene film of the present invention that can be manufactured according to embodiments of the present invention. In these examples, a 3-layer oriented polyethylene film can be manufactured using a 3-layer 2.1-meter-wide Biax pilot line. The film can be manufactured using a 3-layer die with a die gap of 3.1 mm, which is cast onto a cooling drum using an air knife pinner. The film can be stretched longitudinally at a draw ratio of 6:1 through a series of heated differential speed rolls, followed by stretching transversely at a draw ratio of 8:1. Additional information regarding the manufacture of these films is provided below.

[0204] 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 and cast onto a cooling drum whose surface temperature can be controlled to 25°C to 50°C to solidify the non-oriented film at a casting speed of about 4 to 6 meters per minute. The non-oriented film is preheated longitudinally during stretching at about 75°C to 145°C and stretched longitudinally at about 100°C to 145°C at a draw ratio of about 6 times the original length. The obtained stretched sheet is annealed at about 20°C to 95°C to reduce heat shrinkage and obtain a uniaxially oriented film. The uniaxially oriented film is introduced into a tenter at a line speed of about 25 to 30 meters per minute, preheated at about 115°C to 130°C, stretched transversely at about 110°C to 145°C at a draw ratio of about 8 times the original width, and then heat-set or annealed at about 105°C to 140°C to reduce internal stress due to orientation and minimize heat shrinkage of the final film, and a relatively thermally stable biaxially oriented film can be obtained. After biaxial orientation, the total thickness of the co-extruded film is nominally 18 microns. The outer layers are each 3.5 micrometers. The biaxially oriented multilayer film may be wound in a roll. The longitudinal orientation relaxation rate can be 3 to 5%, and the transverse orientation relaxation rate can be 3 to 6%.

[0205] The film has the following structure A / B / C, which has a thickness of 3.5 microns / 11 microns / 3.5 microns respectively. Layer B is the core layer, and layers A and C include both the skin layer and the sub-skin layer of the 5-layer film stretching line. The final width is 1.1 meters.

[0206] Films 3 to 10 of the present invention are shown in Table 6.

Table 9

[0207] AFFINITY (trademark) 1880 is commercially available from The Dow Chemical Company, 0.902 g / cm 3It is a polyolefin plastomer having a density and a melt index (I2) of 1 g / 10 minutes. Generally, those skilled in the art can identify various anti-blocking agents and slip agents that can be used in layer C based on the teachings herein. An example of an anti-blocking agent that can be used is CON-X AB 601 PE commercially available from Kafrit Group. An example of a slip agent that can be used is CON-X SL 504 PE commercially available from Kafrit Group. The present invention includes the following aspects. Item 1. A biaxially oriented multilayer polyethylene film, comprising at least one inner layer, wherein the inner layer (1) is a polyethylene-based composition, (a) at least 97% based on the total weight of the polyethylene-based composition, of 0.926 g / cm 3 ~0.970 g / cm 3 having a density and a melt index (I2) of 0.1 to 10 g / 10 minutes of one or more polyethylenes, and (b) 20 to 5000 ppm based on the total weight of the polyethylene-based composition, of a sorbitol acetal derivative containing the structure of formula (I), and comprising a polyethylene-based composition, [Chemical formula] wherein R1 to R5 are the same or different moieties selected from hydrogen and C1-C3 alkyl, a biaxially oriented multilayer polyethylene film. Item 2. The film according to Item 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. Item 3. A uniaxially oriented multilayer polyethylene film, comprising at least one inner layer, wherein the inner layer (1) is a polyethylene-based composition, (a) At least 97% based on the total weight of the polyethylene-based composition, having a density of 0.926 g / cm 3 ~0.970 g / cm 3 and a melt index (I2) of 0.1 to 10 g / 10 min, one or more polyethylenes, and (b) 20 to 5000 ppm based on the total weight of the polyethylene-based composition, a sorbitol acetal derivative containing the structure of formula (I), a polyethylene-based composition comprising [Chemical formula] In the formula, R1 to R5 are the same or different moieties selected from hydrogen and C1 to C3 alkyl, a uniaxially oriented multilayer polyethylene film. Item 4. The film according to item 3, wherein the film is oriented in the longitudinal direction at a draw ratio of 2:1 to 9:1. Item 5. Further comprising a second polyethylene composition, the second polyethylene composition showing at least two local peaks in the comonomer distribution measured by crystallization elution fractionation, excluding the soluble fraction, and one of the peaks being 40°C to 95°C, the film according to any one of items 1 to 4. Item 6. The film according to item 5, wherein the layer containing the polyethylene-based composition further comprises the second polyethylene composition. Item 7. The overall density is 0.931 to 0.975 g / cm 3 , the film according to any one of items 1 to 6. Item 8. The film according to any one of items 1 to 7, wherein the film has a thickness of 5 to 50 microns. Item 9. The film according to any one of items 1 to 8, further comprising a layer containing polyamide, ethylene vinyl alcohol, or a copolymer of ethylene and carboxylic acid. Item 10. The film according to any one of items 1 to 9, wherein the outer layer is a sealant layer. Item 11. The film according to any one of Items 1 to 10, further comprising a layer containing a metal deposited on the outer layer of the film, wherein the metal contains Al, Zn, Au, Ag, Cu, Ni, Cr, Ge, Se, Ti, Sn, Si, or an oxide thereof. Item 12. An article comprising the film according to any one of Items 1 to 11. Item 13. A laminate comprising: a first film containing a polyethylene sealant film, polyethylene terephthalate, polypropylene, or polyamide; and the multilayer polyethylene film according to any one of Items 1 to 11, wherein the first film is laminated on the multilayer polyethylene film. Item 14. An article comprising the laminate according to Item 13.

Claims

1. A biaxially oriented multilayer polyethylene film, comprising: at least one inner layer, wherein the inner layer is: (1) a polyethylene-based composition, comprising: (a) at least 97% based on the total weight of the polyethylene-based composition, one or more polyethylenes having a density of 0.926 g / cm ３ to 0.970 g / cm ３ and a melt index (I2) of 0.1 to 10 g / 10 min; and (b) 20 to 5000 ppm based on the total weight of the polyethylene-based composition, a sorbitol acetal derivative containing the structure of formula (I); 【Chemical Formula 1】 wherein R1 to R5 are the same or different moieties selected from hydrogen and C １ to C ３ alkyl; The film is oriented longitudinally at a draw ratio of 2:1 to 9:1 and transversely at a draw ratio of 6:1 to 9:

1. A biaxially oriented multilayer polyethylene film.

2. A uniaxially oriented multilayer polyethylene film, comprising: at least one inner layer, wherein the inner layer is: (1) a polyethylene-based composition, comprising: (a) at least 97% based on the total weight of the polyethylene-based composition, one or more polyethylenes having a density of 0.926 g / cm ３ to 0.970 g / cm ３ and a melt index (I2) of 0.1 to 10 g / 10 min; and (b) 20 to 5000 ppm based on the total weight of the polyethylene-based composition, a sorbitol acetal derivative containing the structure of formula (I); 【Chemical Formula 2】 wherein R1 to R5 are the same or different moieties selected from hydrogen and C １ to C ３ comprising the same or different moieties selected from alkyl, a uniaxially oriented multilayer polyethylene film, wherein the film is oriented in the longitudinal direction at a draw ratio of 2:1 to 9:

1. **Claim 3** 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, the film according to claim 1 or 2. **Claim 4** the film according to claim 3, wherein the layer comprising the polyethylene-based composition further comprises the second polyethylene composition. **Claim 5** having an overall density of 0.931 to 0.975 g / cm ３ the film according to any one of claims 1 to 4. **Claim 6** further comprising a layer containing a metal deposited on the outer layer of the film, wherein the metal comprises Al, Zn, Au, Ag, Cu, Ni, Cr, Ge, Se, Ti, Sn, Si, or oxides thereof, the film according to any one of claims 1 to 5. **Claim 7** An article comprising the film according to any one of claims 1 to 6. **Claim 8** a laminate, a first film comprising a polyethylene sealant film, polyethylene terephthalate, polypropylene, or polyamide, and the multilayer polyethylene film according to any one of claims 1 to 6, wherein the first film is laminated to the multilayer polyethylene film.

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