Polyethylene composition and film comprising a polyethylene composition

Abstract

Disclosed are polyethylene compositions that can have a density from 0.910 g / cm 3 to 0.924 g / cm 3 and a melt index (I) from 0.1 g / 10 minutes to 0.5 g / 10 minutes and include a first polyethylene fraction area in the temperature range from 45 °C to 80 °C of an elution profile obtained via an improved comonomer composition distribution (iCCD) analysis method; a second polyethylene fraction area in the temperature range from 80 °C to 95 °C of the elution profile and a third polyethylene fraction area in the temperature range from 95 °C to 110 °C of the elution profile. The second polyethylene fraction area can account for at least 5% of the total area of the elution profile. The third polyethylene fraction area can account for at least 25% of the total area of the elution profile. The ratio of the first polyethylene fraction area to the second polyethylene fraction area can be from 6 to 15.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Application Serial No. 63 / 046,386, filed June 30, 2020, which is incorporated herein by reference in its entirety. Technical Field

[0003]

[0014] Embodiments described herein relate generally to polyethylene compositions, and more particularly, to multilayer films comprising the polyethylene compositions. Background Art

[0004] Multilayer films are used in packaging applications, including flexible packaging applications. It is advantageous for single-layer and multilayer polymeric films (which may include blown or cast films) to exhibit sufficient toughness and puncture properties while allowing for reduced material costs, for example, by film downgauging (i.e., using thinner film gauges), or reducing or eliminating relatively expensive materials such as polyamides. Summary of the Invention

[0005] The various polymerization techniques that use different catalyst systems have been used to produce this polyolefin composition that is applicable to packaging applications.Yet, although aspect the composition that is applicable to packaging applications in development, carried out research effort, still need to be applicable to the composition of packaging applications, it realizes good physical property balance under ideal polymer composition density.In addition, in order to realize this balance, conventional method can mix polar materials, and for example polyamide, compares with utilizing other polyolefin, and this can increase process complexity, increases film structure complexity, produces non-recyclable multilayer film, and increases material cost.

[0006] Therefore, it would be beneficial for monolayer and multilayer polymer films (including blown or cast films) to exhibit toughness while allowing for reduced material costs and / or increased recyclability.There is a need for multilayer films that exhibit stiffness and physical properties (such as puncture properties) that meet customer and industry requirements.

[0007] Embodiments of the present disclosure meet those needs by providing polyethylene compositions that, when used in monolayer or multilayer films, can provide a balance of improved stiffness and improved abuse properties (e.g., dart drop, puncture energy, tear). In one or more embodiments, the polyethylene composition can comprise an area of ​​a first polyethylene fraction, an area of ​​a second polyethylene fraction, and an area of ​​a third polyethylene fraction, wherein each fraction has an area within an elution curve as described herein. Use of such polyethylene compositions can allow for suitable puncture properties versus modulus.

[0008] According to one or more embodiments, a polyethylene composition is provided. The polyethylene composition can include a first polyethylene fraction area in a temperature range of 45°C to 80°C of an elution curve obtained by an improved comonomer composition distribution (iCCD) analysis method. A second polyethylene fraction area in a temperature range of 80°C to 95°C of the elution curve obtained by the iCCD analysis method and a third polyethylene fraction area in a temperature range of 95°C to 120°C of the elution curve obtained by the iCCD analysis method. The second polyethylene fraction area can account for at least 5% of a total area of the elution curve. The third polyethylene fraction area can account for at least 25% of the total area of the elution curve. A ratio of the first polyethylene fraction area to the second polyethylene fraction area can be 6 to 15. The polyethylene composition can have a density of 0.910 g / cm 3 to 0.924 g / cm 3 and a melt index (I2) of 0.1 g / 10 min to 0.5 g / 10 min.

[0009] According to one or more embodiments, a polyethylene composition is provided. The polyethylene composition can include a first polyethylene fraction area in a temperature range of 45°C to 80°C of an elution curve obtained by an improved comonomer composition distribution (iCCD) analysis method. A second polyethylene fraction area in a temperature range of 80°C to 95°C of the elution curve obtained by the iCCD analysis method, wherein the second polyethylene fraction area accounts for at least 5% of a total area of the elution curve; and a third polyethylene fraction area in a temperature range of 95°C to 120°C of the elution curve obtained by the iCCD analysis method, wherein the third polyethylene fraction area accounts for at least 25% of the total area of the elution curve. The polyethylene composition can have a density of 0.910 g / cm 3 to 0.924 g / cm 3 , a melt index (I2) of 0.1 g / 10 min to 0.5 g / 10 min, and a molecular weight distribution in a range of 2.0 to 5.0, the molecular weight distribution being expressed as a ratio of weight average molecular weight to number average molecular weight (Mw / Mn).

[0010] According to one or more additional embodiments, a film is provided. The film can be a monolayer film or a multilayer film comprising a polyethylene composition in at least one layer of the film. The polyethylene composition can comprise a first polyethylene fraction area in a temperature range from 45°C to 80°C of an elution curve obtained by an improved comonomer composition distribution (iCCD) analysis method. A second polyethylene fraction area in a temperature range from 80°C to 95°C of the elution curve obtained by the iCCD analysis method and a third polyethylene fraction area in a temperature range from 95°C to 120°C of the elution curve obtained by the iCCD analysis method. The second polyethylene fraction area can comprise at least 5% of the total area of the elution curve. The third polyethylene fraction area can comprise at least 25% of the total area of the elution curve. A ratio of the first polyethylene fraction area to the second polyethylene fraction area can be from 6 to 15. The polyethylene composition can have a density from 0.910 g / cm3to 0.924 g / cm3and a melt index (I2) from 0.1 g / 10 min to 0.5 g / 10 min. 3 3

[0011] These and embodiments are described in more detail in the following detailed description of specific embodiments in conjunction with the following figures. BRIEF DESCRIPTION OF DRAWINGS

[0012] The following detailed description of specific embodiments of the disclosure can best be understood in conjunction with the accompanying drawings, in which like reference numbers refer to like structures throughout the several views and in which:

[0013] Figure 1 elution curve of a polyethylene composition according to one or more embodiments presently described is graphically depicted; and

[0014] Figure 2 a reactor system for producing a polyethylene composition according to one or more embodiments presently described is schematically depicted. DETAILED DESCRIPTION

[0015] Specific embodiments of the application will now be described. These embodiments are provided to make the disclosure thorough and complete, and to convey the scope of the subject matter for which protection is sought to those skilled in the art.

[0016] ​​The term "polymer" refers to polymeric compounds prepared by polymerizing monomers of the same or different type. Thus, the general term polymer encompasses the term "homopolymer," which generally refers to a polymer prepared from only one type of monomer, and "copolymer," which refers to a polymer prepared from two or more different monomers. The term "interpolymer" as used herein means a polymer prepared by polymerizing at least two different types of monomers. Thus, the general term interpolymer includes copolymers or polymers prepared from more than two different types of monomers, such as terpolymers.

[0017] "Polyethylene" or "ethylene-based polymer" shall mean a polymer comprising greater than 50 mole percent of units derived from ethylene monomer. This includes ethylene-based homopolymers or copolymers (meaning units derived from two or more comonomers). Common forms of ethylene-based polymers known in the art include, but are not limited to: low density polyethylene (LDPE); linear low density polyethylene (LLDPE); ultra low density polyethylene (ULDPE); very low density polyethylene (VLDPE); single-site catalyzed linear low density polyethylene, including both linear low density resins and substantially linear low density resins (m-LLDPE); medium density polyethylene (MDPE); and high density polyethylene (HDPE).

[0018] As used herein, the term "composition" refers to mixtures of materials which comprise the composition, as well as reaction products and decomposition products formed from the materials of the composition.

[0019] As used herein, "polypropylene" or "propylene-based polymer" means a polymer comprising greater than 50 mole percent of units derived from propylene monomer in polymerized form. This includes propylene homopolymers, polypropylene random copolymers, impact copolymer polypropylenes, propylene / alpha olefin copolymers, and propylene / alpha olefin copolymers.

[0020] The term "LDPE" can also be referred to as "high pressure ethylene polymer" or "highly branched polyethylene" and is defined to mean that the polymer is partially or completely homopolymerized or copolymerized in autoclave or tubular reactors at pressures above 14,500 psi (100 MPa) using free radical initiators such as peroxides (see, for example, U.S. Patent No. 4,599,392, which is incorporated by reference herein in its entirety). LDPE resins typically have densities in the range of 0.916 g / cm3to 0.940 g / cm3. 3 to 0.940 g / cm3. 3

[0021] ​The term "LLDPE" includes resins made using Ziegler-Natta catalyst systems as well as resins made using single-site catalysts, including but not limited to bis-metallocene catalysts (sometimes referred to as "m-LLDPE"), phosphinimine, constrained geometry catalysts; and resins made using post-metallocene molecular catalysts, including but not limited to bis(biphenylphenyl ether) catalysts (also referred to as polyvalent aryloxy ether catalysts). LLDPE includes linear, substantially linear, or heterogeneous ethylene-based copolymers or homopolymers. LLDPE contains less long chain branching than LDPE and includes substantially linear ethylene polymers, which are further defined in U.S. Patent No. 5,272,236, U.S. Patent No. 5,278,272, U.S. Patent No. 5,582,923, and U.S. Patent No. 5,733,155, each of which is incorporated herein by reference in its entirety; homogeneous branched linear ethylene polymer compositions, such as those described in U.S. Patent No. 3,645,992, incorporated herein by reference in its entirety; heterogeneous branched ethylene polymers, such as those prepared according to the process disclosed in U.S. Patent No. 4,076,698, incorporated herein by reference in its entirety; and blends thereof (such as those disclosed in U.S. Patent No. 3,914,342 and U.S. Patent No. 5,854,045), incorporated herein by reference in their entirety. LLDPE resins can be prepared via gas phase, solution phase, or slurry polymerization, or any combination thereof, using any type of reactor or reactor configuration known in the art.

[0022] The term "HDPE" means a polyethylene having a density greater than 0.935 g / cm 3 and up to 0.980 g / cm 3 which is typically made with Ziegler-Natta catalysts, chromium catalysts, or single-site catalysts, including but not limited to substituted mono- or bis-cyclopentadienyl catalysts (commonly referred to as metallocenes), constrained geometry catalysts, phosphinimine catalysts, and polyvalent catalyst aryloxy ether catalysts (commonly referred to as bisphenylphenoxy).

[0023] The term "ULDPE" means a polyethylene having a density of 0.855 g / cm 3 to 0.912 g / cm 3polyethylenes, which are typically made with Ziegler-Natta catalysts, chromium catalysts, or single-site catalysts, including but not limited to substituted mono- or bis-cyclopentadienyl catalysts (often referred to as metallocenes), geometry-restricted catalysts, phosphinimine catalysts, and polyvalent aryloxyether catalysts (often referred to as bisphenylphenoxy). ULDPEs include, but are not limited to, polyethylene (ethylene-based) plastomers and polyethylene (ethylene-based) elastomers. Polyethylene (ethylene-based) elastomer plastomers typically have a density of 0.855 g / cm3 3 to 0.912 g / cm3 3 .

[0024] “Blends,”“polymer blends,” and like terms mean a composition of two or more polymers. Such blends can or can not be miscible. Such blends can or can not be phase separated. Such blends can or can not contain one or more domain configurations, as determined by transmission electron spectroscopy, light scattering, x-ray scattering, and any other methods known in the art. Blends are not laminates, but one or more layers of a laminate can contain a blend. Such blends can be prepared as dry blends, formed in situ (e.g., in a reactor), melt blended, or using other techniques known to those skilled in the art.

[0025] “Multilayer structure” or“multilayer film” means any structure having more than one layer. For example, a multilayer structure (e.g., film) can have two layers, three layers, four layers, five layers, six layers, seven layers, or more. A multilayer structure can be described as having layers denoted by letters. For example, a three layer structure designated as A / B / C can have a core layer (B) and two outer layers (A) and (C).

[0026] The terms“comprising,”“including,”“having,” and their derivatives, are not intended to exclude any additional component, step or procedure, whether or not the same is specifically disclosed. In order to avoid any doubt, all compositions claimed through use of the term“comprising” can include any additional additive, adjuvant, or compound, whether polymeric or otherwise, that is optional to the claimed composition, unless stated otherwise. Conversely, the term“consisting essentially of’ excludes from the range of equivalents any additional component, step or procedure that (a) materially alters or changes the nature of the composition as described, (b) does not materially advance the progress of the art, or (c) is not otherwise reasonably suggested by the prior art to be an essential element of the claimed invention. The term“consisting of’ excludes any component, step or procedure not specifically recited.

[0027] Multimodal polyethylene compositions and characterization

[0028] As used herein, the polyethylene composition disclosed herein may be referred to as a "multimodal polyethylene composition". In one or more embodiments, the multimodal polyethylene composition is composed of ethylene and a comonomer such as C3-C 12 The polymerization of olefins forms. Contemplated comonomers include C6-C9 olefins, such as 1-octene and 1-hexene. In one or more embodiments, the comonomer is 1-octene.

[0029] In one or more embodiments, the multimodal polyethylene composition may have a density of 0.910 g / cm² when measured according to ASTM D792. 3 to 0.924g / cm 3 In an embodiment, the multimodal polyethylene composition disclosed herein may have a density of 0.910 g / cm2 when measured according to ASTM D792. 3 to 0.922g / cm 3 、0.910g / cm 3 to 0.920g / cm 3 、0.910g / cm 3 to 0.918g / cm 3 、0.910g / cm 3 to 0.916g / cm 3 、0.910g / cm 3 to 0.914g / cm 3 、0.910g / cm 3 to 0.912g / cm 3 , 0.912g / cm 3 to 0.924g / cm 3 , 0.912g / cm 3 to 0.922g / cm 3 , 0.912g / cm 3 to 0.920g / cm 3 , 0.912g / cm 3 to 0.918g / cm 3 , 0.912g / cm 3 to 0.916g / cm 3 , 0.912g / cm 3 to 0.914g / cm 3 , 0.914g / cm 3 to 0.924g / cm 3 , 0.914g / cm 3 to 0.922g / cm 3 , 0.914g / cm 3 to 0.920g / cm 3 , 0.914g / cm3 to 0.918 g / cm 3 , 0.914 g / cm 3 to 0.916 g / cm 3 , 0.916 g / cm 3 to 0.924 g / cm 3 , 0.916 g / cm 3 to 0.922 g / cm 3 , 0.916 g / cm 3 to 0.920 g / cm 3 , 0.916 g / cm 3 to 0.918 g / cm 3 , 0.918 g / cm 3 to 0.924 g / cm 3 , 0.918 g / cm 3 to 0.922 g / cm 3 , 0.918 g / cm 3 to 0.920 g / cm 3 , 0.920 g / cm 3 to 0.924 g / cm 3 , 0.920 g / cm 3 to 0.922 g / cm 3 , 0.922 g / cm 3 to 0.924 g / cm 3 or any combination of these ranges.

[0030] In one or more embodiments, the multimodal polyethylene composition can have a melt index (I2) of 0.1 g / 10 minutes (g / 10 min) to 0.5 g / 10 min when measured according to ASTM D-1238 at 190 °C and 2.16 kg. In embodiments, the multimodal polyethylene composition can have a melt index (I2) of 0.1 g / 10 min to 0.4 g / 10 min, 0.1 g / 10 min to 0.3 g / 10 min, 0.1 g / 10 min to 0.2 g / 10 min, 0.2 g / 10 min to 0.5 g / 10 min, 0.2 g / 10 min to 0.4 g / 10 min, 0.2 g / 10 min to 0.3 g / 10 min, 0.3 g / 10 min to 0.5 g / 10 min, 0.3 g / 10 min to 0.4 g / 10 min, 0.4 g / 10 min to 0.5 g / 10 min, or any combination of these ranges when measured according to ASTM D-1238 at 190 °C and 2.16 kg.

[0031] According to embodiments, the multimodal polyethylene composition can have a molecular weight distribution, expressed as the ratio of weight average molecular weight to number average molecular weight (Mw / Mn), in the range of 2.0 to 5.0. In embodiments, the molecular weight distribution of the multimodal polyethylene composition can be: 2.0 to 4.5, 2.0 to 4.0, 2.0 to 3.5, 2.0 to 3.0, 2.0 to 2.5, 2.5 to 5.0, 2.5 to 4.5, 2.5 to 4.0, 2.5 to 3.5, 2.5 to 3.0, 3.0 to 5.0, 3.0 to 4.5, 3.0 to 4.0, 3.0 to 3.5, 3.5 to 5.0, 3.5 to 4.5, 3.5 to 4.0, 4.0 to 5.0, 4.0 to 4.5, 4.5 to 5.0, or any combination of these ranges. As presently described, the molecular weight distribution can be calculated according to gel permeation chromatography (GPC) techniques as described herein.

[0032] According to one or more embodiments, the multimodal polyethylene composition can have a zero shear viscosity ratio in the range of 3.0 to 6.0. In embodiments, the multimodal polyethylene composition can have a zero shear viscosity ratio in the range of: 3.0 to 5.5, 3.0 to 5.0, 3.0 to 4.5, 3.0 to 4.0, 3.0 to 3.5, 3.5 to 6.0, 3.5 to 5.5, 3.5 to 5.0, 3.5 to 4.5, 3.5 to 4.0, 4.0 to 6.0, 4.0 to 5.5, 4.0 to 5.0, 4.0 to 4.5, 4.5 to 6.0, 4.5 to 5.5, 4.5 to 5.0, 5.0 to 6.0, 5.0 to 5.5, 5.5 to 6.0, or any combination of these ranges.

[0033] According to further embodiments, the multimodal polyethylene composition can have a Dow Rheology Index of less than or equal to 5, for example, less than or equal to 4, less than or equal to 3, less than or equal to 2, or even less than or equal to 1.

[0034] In one or more embodiments, the presently disclosed multimodal polyethylene composition can further comprise additional components, such as one or more additives. Such additives include, but are not limited to, antistatic agents, color enhancers, dyes, lubricants, fillers (such as Ti02or CaC03), opacifiers, nucleating agents, processing aids, pigments, primary antioxidants, secondary antioxidants, UV stabilizers, anticaking agents, slip agents, slip additives, flame retardants, antimicrobials, odor-reducing agents, antifungal agents, and combinations thereof. The multimodal polyethylene composition can comprise 0.1% to 10% of such additives in combined weight, based on the weight of the multimodal polyethylene composition including such additives.

[0035] As described herein, a polyethylene "fraction" refers to a portion of the total composition of a multimodal polyethylene composition. The presently disclosed embodiments include at least a "first polyethylene fraction," a "second polyethylene fraction," and a "third polyethylene fraction." The various fractions included in the multimodal polyethylene composition can be quantified by their temperature ranges in elution profiles obtained via an improved comonomer composition distribution (iCCD) analysis method. Unless otherwise specified, any elution profile referenced herein is an elution profile observed by iCCD. Embodiments of such fractions will be better understood in view of the examples provided herein. Generally, a first fraction can include peaks within a temperature range of the first fraction, a second fraction can include peaks within a temperature range of the second fraction, and a third fraction can include peaks within a temperature range of the third fraction. The multimodal polyethylene compositions described herein can be referred to as "multimodal," meaning that they include at least two peaks in their elution profiles. Some embodiments can be "trimodal," meaning that there are three primary peaks.

[0036] Referring to the described iCCD distribution, Figure 1 A sample iCCD distribution 100 is schematically depicted along with a cumulative weight fraction curve 200. Figure 1 Several features of the iCCD profile are generally depicted, including a fraction 102 and a fraction 106. The fraction 102 has a peak 104, and the fraction 106 has a peak 108. Each fraction has a half-peak width 110 and a half-peak width 112. It should be understood that, Figure 1 The curve of FIG. 2 is not derived from experiment or observation, but is provided for informational purposes to describe certain features of an iCCD elution profile.

[0037] In one or more embodiments, the multimodal polyethylene compositions described herein can have a first polyethylene fraction defined by an area of an elution profile obtained via an improved comonomer composition distribution (iCCD) analysis method within a temperature range of 45 °C to 80 °C. As used herein, in some embodiments, the first polyethylene fraction area can be defined as the area under the monomodal of the first polyethylene fraction between 45 °C and 80 °C in the elution profile. The first polyethylene area fraction can correspond to the total relative mass of that polymer fraction in the multimodal polyethylene composition.

[0038] In embodiments, the first polyethylene fraction can have a single peak in the elution profile obtained by iCCD in the temperature range of 45 °C to 80 °C. As used herein, “single peak” refers to an iCCD in which a particular fraction includes only a single peak. That is, in some embodiments, the iCCD of the first polyethylene fraction includes only an upward sloping region followed by a downward sloping region to form a single peak. In one or more embodiments, the single peak of the first polyethylene fraction can be in the temperature range of 45 °C to 80 °C, such as 40 °C to 75 °C. Without being bound by theory, it is believed that in at least some embodiments of the presently disclosed polyethylene compositions, in which a dual reactor design is used for polymerization, there can be a combination of crystalline domains of higher density and amorphous domains of lower density. Impact strength is primarily controlled by the amorphous regions or the concentration of tie chains connecting adjacent lamellae. When the density is less than 0.910 g / cm3, the relative tie chain concentration is estimated to be relatively large. The peak of the first polymer fraction in the presently disclosed compositions can be in the temperature range of 45 °C to 80 °C, which can provide a greater tie chain concentration to obtain functional benefits such as improved toughness. 3

[0039] It should be understood that the peak in the first polyethylene fraction can not be formed from a local minimum in the respective polyethylene fraction at a defined temperature boundary. That is, the peak must be a peak across the entire spectral range, and not a peak formed by a threshold temperature of the polyethylene fraction. For example, if there is a single peak in the polyethylene fraction followed by a single valley (upward slope followed by a downward slope, followed by an upward slope), then there will only be a single peak in such a polyethylene fraction.

[0040] In one or more embodiments, the first polyethylene fraction area can be at least 40% of the total area of the elution profile (e.g., at least 42%, at least 44%, at least 46%, at least 48%, at least at least 50%, at least 52%, or even at least 54% of the total area of the elution profile). For example, the first polyethylene fraction area can be 40% to 65% of the total area of the elution profile, such as 40% to 60%, 40% to 55%, 40% to 50%, 40% to 45%, 45% to 65%, 45% to 60%, 45% to 55%, 45% to 50%, 50% to 65%, 50% to 60%, 50% to 55%, 55% to 65%, 55% to 60%, or 60% to 65% of the total area of the elution profile.

[0041] ​In one or more embodiments, the first polyethylene fraction can have a weight average molecular weight of less than or equal to 250,000 g / mol, for example, 20,000 g / mol to 250,000 g / mol or 20,000 g / mol to 200,000 g / mol. In embodiments, the first polyethylene fraction can have a weight average molecular weight of 20,000 g / mol to 250,000 g / mol, 20,000 g / mol to 200,000 g / mol, 20,000 g / mol to 150,000 g / mol, 20,000 g / mol to 100,000 g / mol, 20,000 g / mol to 50,000 g / mol, 50,000 g / mol to 250,000 g / mol, 50,000 g / mol to 200,000 g / mol, 50,000 g / mol to 150,000 g / mol, 50,000 g / mol to 100,000 g / mol, 100,000 g / mol to 250,000 g / mol, 100,000 g / mol to 200,000 g / mol, 100,000 g / mol to 150,000 g / mol, 150,000 g / mol to 250,000 g / mol, 150,000 g / mol to 200,000 g / mol, 200,000 g / mol to 250,000 g / mol, or any combination of these ranges. The molecular weight of the polyethylene fraction can be calculated based on GPC results, as described below.

[0042] In one or more embodiments, the multimodal polyethylene composition can have a second polyethylene fraction defined by the area of the elution curve in the temperature range of 80°C to 95°C obtained by the improved comonomer composition distribution (iCCD) analysis method. As used herein, the second polyethylene fraction area can be defined as the area under the monomodal of the second polyethylene fraction in the elution curve between 80°C and 95°C. Without being bound by theory, it is believed that the comonomer distribution in the second polyethylene fraction can contribute to improved properties when the multimodal polyethylene composition is extruded into a film. For example, such improved properties can include improved puncture resistance.

[0043] The second polyethylene area fraction can correspond to the total relative mass of that polymer fraction in the multimodal polyethylene composition. In one or more embodiments, the second polyethylene fraction can include a local minimum in the elution curve. The local minimum can fall between the peak of the first polyethylene fraction and the peak of the third polyethylene fraction.

[0044] According to one or more embodiments, the second polyethylene fraction area can comprise at least 5% (e.g., at least 6%, at least 8%, or even at least 10% of the total area of the elution profile). For example, the first polyethylene fraction area can comprise from 5% to 15%, from 5% to 10%, or from 10% to 15% of the total area of the elution profile.

[0045] According to some embodiments, the ratio of the first polyethylene fraction area to the second polyethylene fraction area can be from 6 to 15, from 6 to 10, from 10 to 15, or any combination of these ranges.

[0046] According to some embodiments, the ratio of the weight average molecular weight of the first polyethylene fraction area to the weight average molecular weight of the second polyethylene fraction area can be from 0.75 to 1.50, from 0.75 to 1.25, from 0.75 to 1.00, from 1.00 to 1.50, from 1.00 to 1.25, from 1.25 to 1.50, or any combination of these ranges.

[0047] In one or more embodiments, the second polyethylene fraction can have a weight average molecular weight from 80,000 g / mol to 200,000 g / mol or from 80,000 g / mol to 150,000 g / mol. In further embodiments, the second polyethylene fraction can have a weight average molecular weight from 80,000 g / mol to 200,000 g / mol, from 80,000 g / mol to 150,000 g / mol, from 80,000 g / mol to 100,000 g / mol, from 100,000 g / mol to 200,000 g / mol, from 100,000 g / mol to 150,000 g / mol, from 150,000 g / mol to 200,000 g / mol, or any combination of these ranges. The molecular weight of the polyethylene fractions can be calculated based on GPC results, as described below.

[0048] In one or more embodiments, the multimodal polyethylene composition can have a third polyethylene fraction defined by the area of the elution profile in the temperature range from 95 °C to 120 °C obtained by the Improved Comonomer Composition Distribution (iCCD) analysis method. As used herein, the third polyethylene fraction area can be defined as the area under the monomodal of the third polyethylene fraction between 95 °C and 120 °C in the elution profile. The first polyethylene area fraction can correspond to the total relative mass of that polymer fraction in the multimodal polyethylene composition.

[0049] In one or more embodiments, the third polyethylene fraction can have a single peak in the elution profile obtained by iCCD in the temperature range of 95 °C and 120 °C. It will be appreciated that the peak in the third polyethylene fraction can not be formed by a local minimum in the respective polyethylene fraction at the defined temperature boundary. That is, the peak must be a peak across the entire spectral range, and not a peak formed by a threshold temperature of the polyethylene fraction. For example, if there is a single peak in the polyethylene fraction, followed by a single valley (an upward slope, followed by a downward slope, followed by an upward slope), then there will only be a single peak in such a polyethylene fraction. The temperature range of 95 °C to 120 °C for the third polyethylene fraction can be desirable because the low molecular weight, high density component at 95 °C and 120 °C can allow the polyethylene to achieve a higher overall density while maintaining a lower density fraction.

[0050] In one or more embodiments, the width of the single peak at 50% peak height for the third polyethylene fraction can be 2 °C to 10 °C, 2 °C to 8 °C, 2 °C to 6 °C, 2 °C to 4 °C, 4 °C to 10 °C, 4 °C to 8 °C, 4 °C to 6 °C, 6 °C to 10 °C, 6 °C to 8 °C, or 8 °C to 10 °C. Generally, a smaller temperature range at 50% peak height corresponds to a “sharper” peak. Without being bound by any particular theory, it is believed that a “sharper” or “narrower” peak is a characteristic caused by the molecular catalyst and indicates minimal comonomer incorporation on the higher density fraction, thereby enabling a higher density separation between the first polyethylene fraction and the third polyethylene fraction.

[0051] According to one or more embodiments, the third polyethylene fraction area can be at least 25% of the total area of the elution profile (e.g., at least 30%, at least 35%, or even at least 40% of the total area of the elution profile). For example, the first polyethylene fraction area can be 25% to 50% of the total area of the elution profile, such as 25% to 45%, 25% to 40%, 25% to 35%, 25% to 30%, 30% to 50%, 30% to 45%, 30% to 40%, 30% to 35%, 35% to 50%, 35% to 45%, 35% to 40%, 40% to 50%, 40% to 45%, or 45% to 50%.

[0052] In one or more embodiments, the third polyethylene fraction can have a weight average molecular weight of less than or equal to 120,000 g / mol, for example, 20,000 g / mol to 120,000 g / mol or 40,000 g / mol to 65,000 g / mol. In further embodiments, the third polyethylene fraction can have a weight average molecular weight of 20,000 g / mol to 40,000 g / mol, 40,000 g / mol to 60,000 g / mol, 60,000 g / mol to 80,000 g / mol, 80,000 g / mol to 100,000 g / mol, 100,000 g / mol to 120,000 g / mol, or any combination of these ranges. The molecular weight of the polyethylene fractions can be calculated based on GPC results, as described below.

[0053] According to one or more embodiments, the difference between the unimodal of the second polyethylene fraction and the unimodal of the first polyethylene fraction can be at least 5°C. For example, the difference between the unimodal of the second polyethylene fraction and the unimodal of the first polyethylene fraction can be at least 6°C, 7°C, 8°C, 9°C, 10°C, 11°C, 12°C, 14°C, 16°C, 18°C, or even at least 20°C.

[0054] Polymerization

[0055] Any conventional polymerization process can be employed to produce the multimodal polyethylene compositions described herein. Such conventional polymerization processes include, but are not limited to, slurry polymerization processes using one or more conventional reactors, for example, loop reactors, isothermal reactors, stirred tank reactors, batch reactors, and / or any combination thereof, in parallel or in series. The multimodal polyethylene compositions can be produced, for example, via solution phase polymerization processes using one or more loop reactors, isothermal reactors, and combinations thereof.

[0056] Generally, the solution phase polymerization processes can be conducted at temperatures in the range of 115°C to 250°C (e.g., 115°C to 210°C) and at pressures in the range of 300 psi to 1,000 psi (e.g., 400 psi to 800 psi) in one or more well-mixed reactors, for example, one or more isothermal loop reactors or one or more adiabatic reactors. In one embodiment, in a dual reactor, the temperature in the first reactor is in the range of 115°C to 190°C (e.g., 160°C to 180°C), while the second reactor temperature is in the range of 150°C to 250°C (e.g., 180°C to 220°C). In embodiments, in a single reactor, the temperature in the reactor is in the range of 115°C to 250°C (e.g., 115°C to 225°C).

[0057] The residence time in the solution phase polymerization process can range from 2 to 30 minutes (e.g., 5 to 25 minutes). Ethylene, solvent, hydrogen, one or more catalyst systems, optionally one or more co-catalysts, and optionally one or more comonomers are continuously fed into one or more reactors. Exemplary solvents include, but are not limited to, isoparaffins. For example, such solvents are commercially available from ExxonMobil Chemical Co., Houston, Texas under the name ISOPAR E. The resulting mixture of the multimodal polyethylene composition and solvent is then removed from the reactor and the multimodal polyethylene composition is isolated. The solvent is typically recovered via a solvent recovery unit (i.e., heat exchanger and vapor-liquid separator drum) and subsequently recycled back into the polymerization system.

[0058] In some embodiments, the multimodal polyethylene composition can be produced via solution polymerization in a dual reactor system (e.g., 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 co-catalysts can be present. In another embodiment, the multimodal polyethylene composition can be produced by solution polymerization in a single reactor system, e.g., a single loop reactor system, where ethylene is polymerized in the presence of two catalyst systems. In some embodiments, only ethylene is polymerized.

[0059] Catalyst system

[0060] Specific embodiments of catalyst systems that can be used in one or more embodiments to produce the multimodal polyethylene compositions described herein will now be described. It should be understood that the catalyst systems of the present disclosure can be embodied in different forms and should not be interpreted as being limited to the specific embodiments set forth in the present disclosure. Rather, the embodiments are provided so that the present disclosure will be thorough and complete, and so that the embodiments will fully convey the scope of the subject matter to those skilled in the art.

[0061] The term "independently selected" is used herein to indicate that the R groups (e.g., R 1 , R 2 , R 3 , R 4 , and R 5 ) can be the same or different (e.g., R 1 , R 2 , R 3 , R 4 , and R 5 may all be substituted alkyl, or R 1 and R 2 may be substituted alkyl and R 3can be aryl, etc.). Use of the singular encompasses use of the plural, and vice versa (e.g., a hexane solvent encompasses a plurality of hexanes). A named R group will generally have an art-recognized structure corresponding to the R group having that name. These definitions are intended to supplement and illustrate, but not to exclude, definitions known to those skilled in the art.

[0062] The term "procatalyst" refers to a compound that has catalytic activity when combined with an activator. The term "activator" refers to a compound that chemically reacts with the procatalyst in a manner that converts the procatalyst into a catalytically active catalyst. As used herein, the terms "procatalyst" and "activator" are interchangeable terms.

[0063] When used to describe certain chemical groups containing carbon atoms, the form "(C x -C y )" means that the unsubstituted form of the chemical group has x to y carbon atoms (inclusive of x and y). For example, (C1-C 40 )alkyl is an alkyl group having 1 to 40 carbon atoms in its unsubstituted form. In some embodiments and general structures, certain chemical groups may be substituted with one or more substituents such as RS. x -C y )" The chemical group defined in brackets is R S The substitution pattern can be based on any group R S The property of containing more than y carbon atoms. For example, " S Substituted (C1-C 40 )alkyl, wherein R S A phenyl group (-C6H5)" may contain from 7 to 46 carbon atoms. Therefore, in general, when the parenthetical phrase "(C x -C y )" is replaced by one or more carbon-containing substituents R S When substituted, both x and y are added to the substituent R from all carbon atoms S The combined sum of the number of carbon atoms is used to determine the minimum and maximum total number of carbon atoms in a chemical group.

[0064] The term "substituted" means that at least one hydrogen atom (-H) bonded to a carbon atom or heteroatom of the corresponding unsubstituted compound or functional group is replaced by a substituent (e.g., R S ) is replaced. The term "persubstituted" means that each hydrogen atom (H) bonded to a carbon atom or heteroatom of the corresponding unsubstituted compound or functional group is replaced by a substituent (e.g., R S) substituted. The term "poly-substituted" means that at least two but fewer than all of the hydrogen atoms bonded to a carbon atom or a heteroatom of the corresponding unsubstituted compound or functional group are replaced with a substituent.

[0065] The term "-H" means a hydrogen or hydrogen group covalently bonded to another atom. "Hydrogen" and "-H" are interchangeable and mean the same thing unless explicitly stated otherwise.

[0066] The term "(C1-C 40 )alkyl" means a saturated straight chain or branched chain hydrocarbon radical of one to forty carbon atoms, and the term "(C1-C 40 )alkylene" means a saturated straight chain or branched chain hydrocarbon diradical of one to forty carbon atoms, wherein each alkyl and each alkylene is aromatic or nonaromatic, saturated or unsaturated, straight-chained or branched, cyclic (including single ring and multiple ring, fused and non-fused multiple ring, including bicyclic; 3 or more carbon atoms) or acyclic, and unsubstituted or substituted with one or more R S substituents.

[0067] In the present disclosure, (C1-C 40 )alkyl is independently 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 foregoing (C1-C 40 )alkyl groups has up to 20 carbon atoms (i.e., (C1-C 20 )alkyl), and in embodiments, up to 12 carbon atoms.

[0068] The terms "(C1-C 40 )alkyl" and "(C1-C 18 )alkyl" mean a saturated straight chain or branched chain hydrocarbon radical of one to forty carbon atoms or one to eighteen carbon atoms, respectively, which is unsubstituted or substituted with one or more R S substituents. Examples of unsubstituted (C1-C 40 )alkyl are unsubstituted (C1-C 20 )alkyl; unsubstituted (C1-C 10 )alkyl; unsubstituted (C1-C5)alkyl; methyl; ethyl; 1 -propyl; 2-propyl; 1 -butyl; 2-butyl; 2-methylpropyl; 1,1 -dimethylethyl; 1 -pentyl; 1 -hexyl; 1 -heptyl; 1 -nonyl; and 1 -decyl. Substituted (C1-C40 Examples of alkyl groups are substituted (Ci-C 20 Examples of alkyl groups are substituted (Ci-C 10 Examples of alkyl groups are substituted (Ci-C 45 ]alkyl groups. The term "[C 45 ]alkyl" (with square brackets) means that up to 45 carbon atoms are present in the group (including substituents), and is for example (C 27 -C 40 )alkyl, which are (Ci-C5)alkyl groups, respectively. Each (Ci-C5)alkyl group can be methyl, trifluoromethyl, ethyl, 1 -propyl, 1 -methylethyl, or 1,1 -dimethylethyl.

[0069] The term "(C6-C 40 )aryl" means a monocyclic, bicyclic, or tricyclic aromatic hydrocarbon group having from 6 to 40 carbon atoms, which is unsubstituted or substituted by one or more R S )groups, wherein at least 6 to 14 carbon atoms are aromatic ring carbon atoms, and the monocyclic-, bicyclic- or tricyclic group contains 1, 2 or 3 rings, respectively. Of the 1 ring is an aromatic ring, and the 2 or 3 rings are independently fused or non-fused, and at least one of the 2 or 3 rings is an aromatic ring. Examples of unsubstituted (C6-C 40 )aryl groups are unsubstituted (C6-C 20 )aryl groups; unsubstituted (C6-C 18 )aryl groups; 2-(Ci-C5)alkyl-phenyl; 2,4-bis(Ci-C5)alkyl-phenyl; phenyl; fluorenyl; tetrahydrofluorenyl; dicyclopentadienyl; hexahydrodicyclopentadienyl; indenyl; dihydroindenyl; naphthyl; tetrahydronaphthyl; and phenanthrene. Examples of substituted (C6-C 40 )aryl groups are substituted (Ci-C 20 )aryl groups; substituted (C6-C 18 )aryl groups; 2,4-bis[(C 20 )alkyl]-phenyl; polyfluorophenyl; pentafluorophenyl; and fluoren-9-one-1 -yl.

[0070] The term "(C3-C 40 )cycloalkyl" means a saturated cyclic hydrocarbon group having from 3 to 40 carbon atoms, which is unsubstituted or substituted by one or more R S groups. Other cycloalkyl groups (e.g., (C x -C y )cycloalkyl) are defined in an analogous manner as having x to y carbon atoms, and being unsubstituted or substituted by one or more R S groups. Examples of unsubstituted (C3-C 40 )cycloalkyl groups are unsubstituted (C3-C20 )cycloalkyl, unsubstituted (C3-C 10 )cycloalkyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl and cyclodecyl. Substituted (C3-C 40 Examples of cycloalkyl groups are substituted (C3-C 20 )cycloalkyl, substituted (C3-C 10 )cycloalkyl, cyclopentanone-2-yl and 1-fluorocyclohexyl.

[0071] (C1-C 40 Examples of the alkylene group include unsubstituted or substituted (C6-C 40 )arylene, (C3-C 40 )cycloalkylene and (C1-C 40 )alkylene (e.g., (C1-C 20 ) alkylene). In some embodiments, the diradicals are located on the same carbon atom (e.g., -CH2-) or on adjacent carbon atoms (i.e., 1,2-diradicals), or are separated by one, two, or more than two intervening carbon atoms (e.g., 1,3-diradicals, 1,4-diradicals, etc.). Some diradicals include α,ω-diradicals. α,ω-diradicals are diradicals with the largest carbon backbone spacing between radical carbons. (C2-C 20 Some examples of alkylene α,ω-diyl groups 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-diyl radicals include phenyl-1,4-diyl, naphthalene-2,6-diyl, or naphthalene-3,7-diyl.

[0072] The term "(C1-C 40 )alkylene" means a group having 1 to 40 carbon atoms which is unsubstituted or substituted with one or more R S Substituted saturated straight or branched chain diradicals (i.e., groups not on ring atoms). Unsubstituted (C1-C 50 Examples of alkylene groups are unsubstituted (C1-C 20 )alkylene, including unsubstituted -CH2CH2-, -(CH2)3-, -(CH2)4-, -(CH2)5-, -(CH2)6-, -(CH2)7-, -(CH2)8-, -CH2C*HCH3, and -(CH2)4C*(H)(CH3), where "C*" represents a carbon atom from which a hydrogen atom is removed to form a secondary or tertiary alkyl group. Substituted (C1-C 50 Examples of alkylene groups are substituted (C1-C 20)alkylene, -CF2-, -C(O)- and -(CH2) 14 C(CH3)2(CH2)5- (i.e., 6,6-dimethyl-substituted n-1,20-eicosene). As mentioned above, the two R S Can form together (C1-C 18 ) alkylene, substituted (C1-C 50 Examples of the alkylene group also include 1,2-bis(methylene)cyclopentane, 1,2-bis(methylene)cyclohexane, 2,3-bis(methylene)-7,7-dimethyl-bicyclo[2.2.1]heptane, and 2,3-bis(methylene)bicyclo[2.2.2]octene.

[0073] The term "(C3-C 40 ) cycloalkylene refers to a cycloalkylene group having 3 to 40 carbon atoms which is unsubstituted or substituted by one or more R S Substituted cyclic diradicals (ie, the radical is on a ring atom).

[0074] The term "heteroatom" refers to an atom other than hydrogen or carbon. Examples of heteroatoms include O, S, S(O), S(O)2, Si(R C )2、P(R P )、N(R N ),-N=C(R C )2、-Ge(R C )2- or -Si(R C )-, where each R C , each R N and each RP is unsubstituted (C1-C 18 )alkyl or -H. The term "heteroalkyl" refers to a molecule or molecular framework in which one or more carbon atoms are replaced by a heteroatom. 40 )heteroalkyl" means a heteroalkyl group having 1 to 40 carbon atoms, and the term "(C1-C 40 ) heteroalkylene" means a heteroalkyl diradical having from 1 to 40 carbon atoms, each heteroalkyl having one or more heteroatoms. The radical of the heteroalkyl group is located on a carbon atom or a heteroatom, and the diradical of the heteroalkyl group can be located on: (1) one or two carbon atoms, (2) one or two heteroatoms, or (3) both carbon atoms and heteroatoms. Each (C1-C 50 ) heteroalkyl and (C1-C 50 ) heteroalkylene may be unsubstituted or substituted with (one or more R S ) substituted, aromatic or non-aromatic, saturated or unsaturated, linear or branched, cyclic (including monocyclic and polycyclic, fused and non-fused polycyclic) or acyclic.

[0075] (C1-C 40) heteroalkyl may be unsubstituted or substituted (C1-C 40 ) heteroalkyl, (C1-C 40 )alkyl-O-, (C1-C 40 )alkyl-S-, (C1-C 40 )alkyl-S(O)-, (C1-C 40 )alkyl-S(O)2-, (C1-C 40 )alkyl-Si(R C )2-、(C1-C 40 )alkyl-N(R N )-、(C1-C 40 )alkyl-P(R P )-、((C2-C 40 )heterocycloalkyl, (C2-C 19 )heterocycloalkyl-(C1-C 20 )alkylene, (C3-C 20 )cycloalkyl-(C1-C 19 )heteroalkylene, (C2-C 19 )heterocycloalkyl-(C1-C 20 )heteroalkylene, (C1-C 40 )heteroaryl, (C1-C 19 )heteroaryl-(C1-C 20 )alkylene, (C6-C 20 )aryl-(C1-C 19 )heteroalkylene, or (C1-C 19 )heteroaryl-(C1-C 20 )heteroalkylene.

[0076] The term "(C4-C 40 ) heteroaryl" means an unsubstituted or substituted (by one or more R S substituted) monocyclic, bicyclic or tricyclic heteroaromatic hydrocarbon groups, and the monocyclic, bicyclic or tricyclic groups contain 1, 2 or 3 rings, respectively, wherein 2 or 3 rings are independently fused or non-fused, and at least one of the 2 or 3 rings is heteroaromatic. Other heteroaryl groups (for example, usually (C x -C y ) heteroaryl, such as (C4-C 12 )heteroaryl) is similarly defined as having x to y carbon atoms (such as 4 to 12 carbon atoms) and being unsubstituted or substituted by one or more than one R SSubstituted. Monocyclic heteroaromatic hydrocarbyl groups are 5- or 6-membered rings. A 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 hydrocarbyl groups are pyrrol-1-yl; piperidin-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. A 6-membered ring has 6 minus h carbon atoms, where h is the number of heteroatoms and can be 1 or 2, and the heteroatoms can be N or P. Examples of 6-membered ring heteroaromatic hydrocarbyl groups are pyridin-2-yl; pyrimidin-2-yl; and pyrazin-2-yl. Bicyclic heteroaromatic hydrocarbyl groups can be fused 5,6- or 6,6-ring systems. Examples of fused 5,6-ring system bicyclic heteroaromatic hydrocarbyl groups are indol-1-yl; and benzimidazol-1-yl. Examples of fused 6,6-ring system bicyclic heteroaromatic hydrocarbyl groups are quinolin-2-yl; and isoquinolin-1-yl. Bicyclic heteroaromatic hydrocarbyl groups can be fused 5,6,5-ring systems; 5,6,6-ring systems; 6,5,6-ring systems; or 6,6,6-ring systems. 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.

[0077] The foregoing heteroalkyl groups can be saturated straight-chained or branched groups containing (C1-C 50 ) carbon atoms, or fewer carbon atoms and one or more heteroatoms. Likewise, heteroalkylene groups can be saturated straight-chained or branched diradicals containing 1 to 50 carbon atoms and one or more than one heteroatom. Heteroatoms as defined above can 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(RN), N, O, OR C , S, SR C , S(O), and S(O)2, where each of the heteroalkyl and heteroalkylene groups is unsubstituted or substituted with one or more R S .

[0078] Unsubstituted (C2-C40 Examples of heterocycloalkyl groups are unsubstituted (C2-C 20 ) heterocycloalkyl, unsubstituted (C2-C 10 ) heterocycloalkyl, aziridin-1-yl, oxetan-2-yl, tetrahydrofuran-3-yl, pyrrolidin-1-yl, tetrahydrothiophen-S,S-dioxy-2-yl, morpholin-4-yl, 1,4-dioxan-2-yl, hexahydroazepin-4-yl, 3-oxa-cyclooctyl, 5-thioxo-cyclononyl and 2-aza-cyclodecyl.

[0079] The term "halogen atom" or "halogen" means a free radical of a fluorine atom (F), a chlorine atom (Cl), a bromine atom (Br), or an iodine atom (I). The term "halide ion" means the anionic form of the following halogen atoms: fluoride ion (F - ), chloride ion (Cl - ), bromide ion (Br - ) or iodide ion (I - ).

[0080] The term "saturated" means free of carbon-carbon double bonds, carbon-carbon triple bonds, and (in heteroatom-containing groups) carbon-nitrogen, carbon-phosphorus, and carbon-silicon double bonds. S In the case of substitution, one or more double bonds and / or triple bonds may or may not be present in the substituent R S The term "unsaturated" means containing one or more carbon-carbon double bonds, carbon-carbon triple bonds and (in heteroatom-containing groups) carbon-nitrogen, carbon-phosphorus and carbon-silicon double bonds, excluding those that may be present in the substituent R S Any such double bonds may be present in the (hetero)aromatic ring (if present) or in the (hetero)aromatic ring (if present).

[0081] According to some embodiments, the catalyst system for producing the polyethylene composition comprises a metal-ligand complex according to formula (I):

[0082]

[0083] In formula (I), M is a metal selected from titanium, zirconium or hafnium, the metal having a formal oxidation state of +2, +3 or +4. n is 0, 1, 2 or 3. When n is 0 and X is absent or for each non-zero n, each X is independently a neutral, monoanionic or dianionic monodentate ligand; or two Xs taken together form a neutral, monoanionic or dianionic bidentate ligand. 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 as a whole is electrically neutral; each Z is independently selected from -O-, -S-, -N(R N )-or-P(RP )-; L is (C1-C 40 )alkylene or (C1-C 40 ) heteroalkylene, wherein (C1-C 40 )alkylene group has a moiety (to which L is bonded) comprising a 1-carbon atom to a 10-carbon atom connecting main chain connecting two Z groups in formula (I), or (C1-C 40 ) heteroalkylene has a moiety comprising a 1-atom to 10-atom connecting backbone linking two Z groups in formula (I), wherein (C1-C 40 ) heteroalkylene groups wherein each of the 1-atom to 10-atom connected backbone atoms is independently a carbon atom or a heteroatom, wherein each heteroatom is independently O, S, S(O), S(O)2, Si(R C )2、Ge(R C )2、P(R C ) or N(R C ), where each R C Independently (C1-C 30 )alkyl or (C1-C 30 ) heteroalkyl; R1 and R8 are independently selected from the group consisting of: -H, (C1-C40)alkyl, (C1-C 40 ) heteroalkyl, -Si(R C )3、-Ge(R C )3、-P(R P )2、-N(R N )2、-OR C 、-SR C 、-NO2、-CN、-CF3、R C S(O)-、R C S(O)2-、(R C )2C=N-、R C C(O)O-、R C OC(O)-、R C C(O)N(R N )-、(R N )2NC(O)-, halogen and groups of formula (II), formula (III) and formula (IV):

[0084]

[0085] In formulas (II), (III) and (IV), R 31-35 、R 41-48 or R 51-59 Each of which is independently selected from (C1-C 40 Hydrocarbon, (C1-C 40 ) heteroalkyl, -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 group having formula (II), formula (III), or formula (IV).

[0086] In formula (I), each of R 2-4 , R 5-7 , and R 9-16 is independently selected from (Ci-C 40 )hydrocarbyl, (Ci-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.

[0087] In some embodiments, the unimodal 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.

[0088] In one exemplary embodiment in which a tandem dual reactor configuration is used, the procatalyst used in the first reactor, such as a continuous stirred tank reactor (CSTR), can comprise a hafnium metal center (M) and is structurally shown in the following structure (V).

[0089]

[0090] In such an embodiment, the procatalyst used in the second reactor, such as a loop reactor, can comprise a hafnium metal center (M) and is structurally shown in the following structure (VI).

[0091]

[0092] Co-catalyst component

[0093] The catalyst system comprising the metal-ligand complex of formula (I) can be rendered catalytically active by any technique known in the art for activating metal-based catalysts for the polymerization of olefins. For example, the system comprising the metal-ligand complex of formula (I) can be rendered catalytically active by contacting the complex with an activating co-catalyst or by combining the complex with an activating co-catalyst. Activating co-catalysts suitable for use herein include alkylaluminums; polymeric or oligomeric aluminoxanes (also known as aluminoxanes); neutral Lewis acids; and non-polymeric, non-coordinating, ion-forming compounds including the use of such compounds under oxidizing conditions. A suitable activation technique is bulk electrolysis. Combinations of one or more of the foregoing activating co-catalysts and techniques are also contemplated. The term "alkylaluminum" means a dihydrogen monoalkylaluminum or dihalogen monoalkylaluminum, a dihydrogen dialkylaluminum or dihalogen dialkylaluminum, or a trialkylaluminum. Examples of polymeric or oligomeric aluminoxanes include methylaluminoxane, methylaluminoxane modified with triisobutylaluminum, and isobutylaluminoxane.

[0094] Lewis acid activators (co-catalysts) include Group 13 metal compounds containing 1 to 3 (Ci-C 20 )hydrocarbyl substituents as described herein. In one embodiment, the Group 13 metal compound is a tri((Ci-C 20 )hydrocarbyl) substituted aluminum or a tri((Ci-C 20 hydrocarbyl)-boron compound. In embodiments, the Group 13 metal compound is a tri(hydrocarbyl) substituted aluminum, a tri((Ci-C 20 )hydrocarbyl)-boron compound, a tri((C6-C 10 )alkyl) aluminum, a tri((C6-C 18 )aryl) boron compound, and halogenated (including perhalogenated) derivatives thereof. In other embodiments, the Group 13 metal compound is a tri(fluoro-substituted phenyl) borane, a tri(pentafluorophenyl) borane. In some embodiments, the activating co-catalyst is a tri((Ci-C20 )alkyl)borate (e.g., trityl tetrafluoroborate) or tri((C1-C 20 )alkyl)ammonium tetra((C1-C 20 )alkyl)borane (e.g., bis(octadecyl)methylammonium tetra(pentafluorophenyl)borane). As used herein, the term “ammonium” means a nitrogen cation which is ((C1-C 20 )alkyl)4N + , ((C1-C 20 )alkyl)3N(H) + , ((C1-C 20 )alkyl)2N(H)2 + , (C1-C 20 )alkylN(H)3 + , or N(H)4 + , where each of the two or more (C1-C 20 )alkyl groups, when present, can be the same or different.

[0095] Combinations of neutral Lewis acid activators (cocatalysts) include mixtures comprising tri((C1-C4)alkyl)aluminum and a halogenated tri((C6-C 18 )aryl)boron compound, especially tris(pentafluorophenyl)borane. Embodiments are combinations of such neutral Lewis acid mixtures with polymeric or oligomeric aluminoxanes and combinations of a single neutral Lewis acid, especially tris(pentafluorophenyl)borane, with polymeric or oligomeric aluminoxanes. The molar ratio of (group 4 metal-ligand complex):(tris(pentafluorophenyl)borane):(aluminoxane) [e.g., (group 4 metal-ligand complex):(tris(pentafluorophenyl)borane):(aluminoxane)] is a ratio of 1:1:1 to 1:10:30, in embodiments 1:1:1.5 to 1:5:10.

[0096] Metal-ligand complex catalyst systems comprising Formula (I) can be activated to form an active catalyst composition by combination with one or more cocatalysts (e.g., 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, but are not limited to, modified methylaluminoxane (MMAO), bis(hydrogenated tallowalkyl)methyl tetra(pentafluorophenyl)borate (1 - )amine, and combinations thereof.

[0097] In some embodiments, one or more of the foregoing activating co-catalysts are used in combination with one another. Especially preferred combinations are mixtures of tri((Ci-C4)hydrocarbyl)aluminum, tri((Ci-C4)hydrocarbyl)borane or ammonium borate with oligomeric or polymeric aluminoxane compounds. The ratio of the total moles of one or more metal-ligand complexes of formula (I) to the total moles of one or more activating co-catalysts is from 1 : 10,000 to 100: 1. In some embodiments, the ratio is at least 1 :5000, in some embodiments, at least 1 : 1000; and 10: 1 or less, and in some embodiments, 1 : 1 or less. When aluminoxane is used alone as the activating co-catalyst, preferably the moles of aluminoxane employed are at least 100 times the moles of metal-ligand complex of formula (I). In some embodiments, when tri(pentafluorophenyl)borane is used alone as the activating co-catalyst, the ratio of the moles of tri(pentafluorophenyl)borane employed to the total moles of one or more metal-ligand complexes of formula (I) is from 0.5: 1 to 10: 1, 1 : 1 to 6: 1, or 1 : 1 to 5: 1. The remaining activating co-catalyst is typically employed in a molar amount approximately equal to the total molar amount of one or more metal-ligand complexes of formula (I).

[0098] Multilayer film

[0099] Reference will now be made to embodiments of the multilayer film described herein.

[0100] The multilayer films of the present disclosure can include at least two layers and up to three, four, five, six, seven, nine, eleven, thirteen, or more layers. The number of layers in the multilayer film can depend on a number of factors including, for example, the composition of each layer in the multilayer film, the desired properties of the multilayer film, the desired end use application of the multilayer film, the manufacturing process of the multilayer film, and the like. As described in greater detail herein, embodiments of the multilayer film can include a first layer as described later in the present disclosure and a second layer as described later in the present disclosure; and one or more sub-skin layers as described later in the present disclosure. The first layer, the second layer, or both can include the multimodal polyethylene composition described herein.

[0101] The multilayer film can be a two layer film designated A / B, where the first layer can be designated (A) and the second layer can be designated (B). As used herein, “direct contact” means that there can be no other layers located between the two layers in direct contact with one another. In embodiments, the first layer (A) can be in direct contact with the second layer (B).

[0102] In embodiments, the multilayer film can be a three-layer film designated as A / B / C, where the first layer can be designated as (A), the second layer can be designated as (B), and the third layer can be designated as (C). In embodiments, the second layer (B) can be positioned between the first layer (A) and the third layer (C), and the second layer (B) can be referred to as the “middle layer” or “core layer.” In embodiments, one or both of the first layer (A) and the third layer (C) can be the outermost layer of the multilayer film, which can be referred to as the “outer layer.” As used herein, the outermost layer of the multilayer film can be understood to mean that no additional layer can be deposited on the outermost layer, such that the outermost layer is in direct contact with the surrounding air. In embodiments, the first layer (A) can be in direct contact with the second layer (B). In embodiments, the second layer (B) can be in direct contact with the third layer (C).

[0103] In embodiments, the multilayer film can include one or more additional layers in addition to the outer layer and the core layer. Such additional layers can include additional layers comprising polyethylene, which can include the multimodal polyethylene composition described herein, and in embodiments can not include the multimodal polyethylene composition described herein. In one or more embodiments, the additional polyethylene layers can include a blend of LLDPE, LDPE, MDPE, HDPE, the multimodal polyethylene composition described herein, and combinations thereof. The various polyethylene components (e.g., LLDPE, LDPE, HDPE, and the multimodal polyethylene composition described herein) can be included in the additional polyethylene layers in any desired amount depending on the properties of the multilayer film to be achieved. Such additional layers can alternatively or additionally include one or more additional tie layers.

[0104] It will be appreciated that any of the foregoing layers can further include one or more additives known to those skilled in the art, such as, for example, plasticizers, stabilizers (including viscosity stabilizers, hydrolysis stabilizers), primary and secondary antioxidants, ultraviolet light absorbers, antistatic agents, dyes, pigments or other colorants, inorganic fillers, flame retardants, lubricants, reinforcing agents (glass fibers and flakes), synthetic (e.g., aramid) fibers or pulp, blowing or foaming agents, processing aids, slip additives, antiblocking agents (such as silica or talc), mold release agents, tackifying resins, or combinations of two or more thereof. Inorganic fillers, such as calcium carbonate and the like, can also be incorporated into one or more of the first layer, the second layer, the third layer, and combinations thereof. In some embodiments, the skin layer, the subsurface layer, the tie layer, the barrier layer, and combinations can each include up to 5 weight percent of such additional additives, based on the total weight of the respective layer. All individual values and subranges of 0 weight percent to 5 weight percent are included herein and disclosed herein; for example, the total amount of additives in the first layer, the second layer, or the third layer can be 0.5 weight percent to 5 weight percent, 0.5 weight percent to 4 weight percent, 0.5 weight percent to 3 weight percent, 0.5 weight percent to 2 weight percent, 0.5 weight percent to 1 weight percent, 1 weight percent to 5 weight percent, 1 weight percent to 4 weight percent, 1 weight percent to 3 weight percent, 1 weight percent to 2 weight percent, 2 weight percent to 5 weight percent, 2 weight percent to 4 weight percent, 2 weight percent to 3 weight percent, 3 weight percent to 5 weight percent, 3 weight percent to 4 weight percent, or 4 weight percent to 5 weight percent, based on the total weight of the respective layer. Incorporation of additives can be performed by any known method, for example, by dry blending, by extruding a mixture of the various ingredients, by conventional masterbatch techniques, and the like.

[0105] The multilayer film of the present disclosure can have a variety of thicknesses. The thickness of the multilayer film can depend on a number of factors, including, for example, the number of layers in the multilayer film, the composition of the layers in the multilayer film, the desired properties of the multilayer film, the desired end-use application of the film, the manufacturing process of the multilayer film, and the like. In embodiments, the multilayer film can have a thickness of less than 205 micrometers (pm or microns). In embodiments, the multilayer film can have a thickness of 15 pm to 205 pm, 20 pm to 180 pm, 15 pm to 180 pm, 15 pm to 160 pm, 15 pm to 140 pm, 15 pm to 120 pm, 15 pm to 100 pm, 15 pm to 80 pm, 15 pm to 60 pm, 15 pm to 40 pm, 20 pm to 160 pm, 20 pm to 140 pm, 20 pm to 120 pm, 20 pm to 100 pm, 20 pm to 80 pm, 20 pm to 60 pm, or 20 pm to 40 pm.

[0106] The multilayer films of the present disclosure can have a total density dependent on a variety of factors, including, for example, the number of layers in the multilayer film, the composition of the layers in the multilayer film, the desired properties of the multilayer film, the desired end-use application of the film, the manufacturing process of the multilayer film, and the like. In embodiments, the multilayer film can have a total density of at least 0.925 grams per cubic centimeter (g / cm 3 ). In embodiments, the multilayer film can have a total density of from 0.925 g / cm 3 to 0.970 g / cm 3 , 0.925 g / cm 3 to 0.940 g / cm 3 , 0.925 g / cm 3 to 0.935 g / cm 3 , 0.925 g / cm 3 to 0.930 g / cm 3 , 0.930 g / cm 3 to 0.940 g / cm 3 , 0.930 g / cm 3 to 0.935 g / cm 3 , 0.935 g / cm 3 to 0.940 g / cm 3 , or 0.935 g / cm 3 to 0.950 g / cm 3 .

[0107] In one or more embodiments, the multilayer films of the present disclosure can have a puncture force of at least 1 Newton per micrometer of film (N / pm) when measured according to ASTM D 5748-95. In embodiments, the multilayer films of the present disclosure can have a puncture force of from 1 N / pm to 1.5 N / pm, 1 N to 1.25 N / pm, or 1.25 N / pm to 1.5 N / pm when measured according to ASTM D 5748-95.

[0108] In one or more embodiments, the multilayer films of the present disclosure can have a puncture resistance of greater than 10 Joules per cubic centimeter (J / cm 3 ) when measured according to ASTM D 5748-95. In embodiments, the multilayer films of the present disclosure can have a puncture resistance of greater than 8 J / cm 3 , or greater than 10 J / cm 3 when measured according to ASTM D 5748-95.

[0109] The multilayer films of the present disclosure can have a puncture elongation of at least 55 millimeters (mm) when measured according to ASTM D 5748-95. In embodiments, the multilayer films of the present disclosure can have a puncture elongation of 55 mm to 150 mm, 55 mm to 100 mm, 55 mm to 80 mm, 55 mm to 60 mm, 60 mm to 150 mm, 60 mm to 100 mm, 60 mm to 80 mm, or 80 mm to 100 mm when measured according to ASTM D 5748-95.

[0110] Outer layer

[0111] As previously mentioned, the multilayer films of the present disclosure can include one or more outer layers. The outermost layer of a multilayer film can be referred to as an “outer layer,” which can be understood to mean that no additional layer can be deposited on the outermost layer, such that the outermost layer is in direct contact with the surrounding air. The outer layer can impart properties to the multilayer film that facilitate stretching, processability, and the like. The outer layer can also be referred to as a skin layer. In embodiments, one or both of the first layer (A) and the third layer (C) can be the outermost layer of the multilayer film, which can be referred to as an “outer layer.”

[0112] The outer layer can include a sealant layer. The sealant layer is typically the outer layer of the film, which can be used to adhere the film to other films, rigid materials (e.g., a tray), or itself. One of ordinary skill in the art will recognize, based on the teachings herein, that a variety of olefin-based polymers can be used as the sealant layer in various embodiments. In some embodiments, to facilitate recyclability, a polyethylene can be the primary component of each sealant layer. According to some embodiments, one non-limiting example of a resin that can be used as a sealant layer is SEALUTION TM 220. Other resins that can be used to form a sealant layer include, but are not limited to, AFFINITY TM , ELITE AT TM , and ELITE TM resins, which are commercially available from The Dow Chemical Company.

[0113] In embodiments, at least one outer layer comprises a multimodal polyethylene composition described herein. In embodiments, an outer layer comprising a multimodal polyethylene composition described herein can be paired with an outer layer having a density of 0.870 g / cm 3 to 0.970 g / cm 3polyethylene blend. In embodiments, the at least one outer layer can comprise greater than 20 wt% of the multimodal polyethylene composition described herein, based on the total weight of the respective layer. In one or more embodiments, each outer layer can comprise greater than 20 wt% of the multimodal polyethylene composition described herein, based on the total weight of the respective layer. In some embodiments, each outer layer can comprise from 0 wt% to 100 wt%, from 30 wt% to 100 wt%, from 50 wt% to 80 wt%, from 50 wt% to 60 wt%, from 60 wt% to 100 wt%, from 60 wt% to 80 wt%, or from 80 wt% to 100 wt% of the multimodal polyethylene composition described herein, based on the total weight of the respective layer. In some embodiments, the outer layer(s) not comprising the multimodal polyethylene composition described herein can comprise a polyethylene having a density from 0.870 g / cm 3 to 0.970 g / cm 3 In embodiments, each outer layer can comprise LLDPE, HDPE, the multimodal polyethylene composition described herein, MDPE, LDPE, and combinations thereof.

[0114] In one or more embodiments, each outer layer can comprise a linear low density polyethylene (LLDPE) having a density from 0.905 g / cm 3 to 0.930 g / cm 3 In another embodiment, the linear low density polyethylene can have a density from 0.905 g / cm 3 to 0.925 g / cm 3 , from 0.905 g / cm 3 to 0.920 g / cm 3 , from 0.905 g / cm 3 to 0.915 g / cm 3 , from 0.905 g / cm 3 to 0.910 g / cm 3 , from 0.910 g / cm 3 to 0.930 g / cm 3 , from 0.910 g / cm 3 to 0.925 g / cm 3 , from 0.910 g / cm 3 to 0.920 g / cm 3 , from 0.910 g / cm 3 to 0.915 g / cm 3 , from 0.915 g / cm 3 to 0.930 g / cm 3 , from 0.915 g / cm 3 to 0.925 g / cm 3 , from 0.915 g / cm3 to 0.920 g / cm 3 , 0.920 g / cm 3 to 0.930 g / cm 3 , 0.920 g / cm 3 to 0.925 g / cm 3 , 0.925 g / cm 3 to 0.930 g / cm 3 .

[0115] In one or more embodiments, each outer layer can include a linear low density polyethylene (LLDPE) having a melt index (I2) from 0.2 grams per 10 minutes (g / 10 min) to 6.0 g / 10 min when measured according to ASTM D1238. It is also contemplated that the melt index (I2) of the linear low density polyethylene can be from 0.2 g / 10 min to 5.5 g / 10 min, 0.2 g / 10 min to 5.0 g / 10 min, or 0.2 g / 10 min to 4.5 g / 10 min, 0.5 g / 10 min to 4.0 g / 10 min, 0.5 g / 10 min to 3.5 g / 10 min, 0.5 g / 10 min to 3.0 g / 10 min, 1.0 g / 10 min to 2.0 g / 10 min, 1.0 g / 10 min to 1.5 g / 10 min, or 1.5 g / 10 min to 2.0 g / 10 min.

[0116] According to embodiments, the linear low density polyethylene can have a molecular weight distribution, expressed as the ratio of weight average molecular weight to number average molecular weight (Mw / Mn), in the range of 3.5 to 5.5. In further embodiments, the linear low density polyethylene can have a molecular weight distribution in the range of 3.5 to 4.5 or 4.5 to 5.5.

[0117] According to one or more further embodiments, the linear low density polyethylene can have a zero shear viscosity ratio from 1.2 to 3.0 when measured according to the test methods described herein. In embodiments, the linear low density polyethylene can have a zero shear viscosity ratio from 1.2 to 2.5, 1.2 to 2.0, 2.0 to 3.0, 2.0 to 2.5, or 2.5 to 3.0.

[0118] Various methods for producing linear low density polyethylene are contemplated. For example, linear low density polyethylene resins can be prepared using Ziegler-Natta catalyst systems, resins prepared using single-site catalysts (including but not limited to dual metallocene catalysts and constrained geometry catalysts), and resins prepared using post-metallocene molecular catalysts. Linear low density polyethylene resins include linear, substantially linear, or heterogeneous polyethylene copolymers or homopolymers. The linear low density polyethylene resin may contain less long chain branching than LDPE and includes substantially linear polyethylene as further defined in U.S. Pat. No. 5,272,236, U.S. Pat. No. 5,278,272, U.S. Pat. No. 5,582,923, and U.S. Pat. No. 5,733,155; a homogeneously branched linear ethylene polymer component such as those in U.S. Pat. No. 3,645,992; a heterogeneously branched ethylene polymer such as those prepared according to the process disclosed in U.S. Pat. No. 4,076,698; and / or blends thereof (such as those disclosed in U.S. Pat. No. 3,914,342 or U.S. Pat. No. 5,854,045). The linear low density polyethylene resin may be prepared via gas phase, solution phase, or slurry polymerization, or any combination thereof, using any type of reactor or reactor configuration known in the art.

[0119] In one or more embodiments, each outer layer may comprise greater than 50 wt% linear low density polyethylene, based on the total weight of the corresponding layer. In some embodiments, the second layer, the third layer, or both may comprise 50 wt% to 100 wt%, 50 wt% to 80 wt%, 50 wt% to 60 wt%, 60 wt% to 100 wt%, 60 wt% to 80 wt%, or 80 wt% to 100 wt% LLDPE, based on the total weight of the corresponding layer.

[0120] In an embodiment, each outer layer may comprise high density polyethylene (HDPE) having a density of 0.935 g / cm² when measured according to ASTM D792. 3 to 0.980g / cm 3 In another embodiment, the density of the high density polyethylene may be 0.935 g / cm 3 to 0.970g / cm 3 , 0.935g / cm 3 to 0.960g / cm 3 , 0.935g / cm 3 to 0.950g / cm 3 , 0.935g / cm 3 to 0.940g / cm 3 、0.940g / cm 3to 0.980 g / cm 3 , 0.940 g / cm 3 to 0.970 g / cm 3 , 0.940 g / cm 3 to 0.960 g / cm 3 , 0.940 g / cm 3 to 0.950 g / cm 3 , 0.950 g / cm 3 to 0.980 g / cm 3 , 0.950 g / cm 3 to 0.970 g / cm 3 , 0.950 g / cm 3 to 0.960 g / cm 3 , 0.960 g / cm 3 to 0.980 g / cm 3 , 0.960 g / cm 3 to 0.970 g / cm 3 , or 0.970 g / cm 3 to 0.980 g / cm 3 .

[0121] In one or more embodiments, each outer layer can include a high density polyethylene having a melt index (I2) of 0.1 grams per 10 minutes (g / 10 min) to 10.0 g / 10 min, when measured according to ASTM D1238 at a load of 2.16 kg and a temperature of 190 °C. It is also contemplated that the melt index (I2) of the high density polyethylene can be 0.1 g / 10 min to 5.0 g / 10 min, 0.1 g / 10 min to 1.0 g / 10 min, or 1.0 g / 10 min to 10.0 g / 10 min, 1.0 g / 10 min to 5.0 g / 10 min, or 5.0 g / 10 min to 10.0 g / 10 min.

[0122] Various methods are contemplated for producing the high density polyethylene. For example, the high density polyethylene resin can be prepared using a Ziegler-Natta catalyst system, a chromium catalyst, or a single-site catalyst, including but not limited to a bis-metallocene catalyst and a shape restricted catalyst.

[0123] In one or more embodiments, each outer layer can include up to 50 weight percent of the high density polyethylene, based on the total weight of the respective layer. In some embodiments, each outer layer can include 0 weight percent to 90 weight percent, 15 weight percent to 80 weight percent, 15 weight percent to 50 weight percent, 20 weight percent to 50 weight percent, 30 weight percent to 40 weight percent, or 35 weight percent to 50 weight percent of the high density polyethylene, based on the total weight of the respective layer.

[0124] In one or more embodiments, each outer layer can include MDPE. The term "MDPE" when used alone refers to a polyethylene having a density of 0.917 to 0.936 g / cm 3 . MDPE is typically made using chromium or Ziegler-Natta catalysts or using single-site catalysts including, but not limited to, substituted mono- or bis-cyclopentadienyl catalysts (often referred to as metallocenes), geometry-restricted catalysts, phosphinimine catalysts, and polyvalent aryloxyether catalysts (often referred to as bisphenylphenoxy). It should be noted that MDPE can be used in one or more outer layers.

[0125] In one or more embodiments, each outer layer can include up to 50 wt% MDPE, based on the total weight of the respective layer. In some embodiments, each outer layer can include from 0 wt% to 90 wt%, from 15 wt% to 80 wt%, from 15 wt% to 50 wt%, from 20 wt% to 50 wt%, from 30 wt% to 40 wt%, or from 35 wt% to 50 wt% MDPE, based on the total weight of the respective layer.

[0126] In embodiments, each outer layer can include a low density polyethylene (LDPE). In one or more embodiments, the low density polyethylene can have a melt index of from 0.1 g / 10 min to 10.0 g / 10 min when measured according to ASTM D1238 at a load of 2.16 kg and a temperature of 190 °C. In embodiments, the low density polyethylene can have a melt index of from 0.1 g / 10 min to 5.0 g / 10 min, or from 0.5 g / 10 min to 5.0 g / 10 min, or from 0.5 g / 10 min to 2.0 g / 10 min. In embodiments, the low density polyethylene can have a density of from 0.916 g / cm 3 to 0.935 g / cm 3 when measured according to ASTM D792. In another embodiment, the low density polyethylene can have a density of from 0.916 g / cm 3 to 0.925 g / cm 3 .

[0127] In one or more embodiments, each outer layer can include less than 50 wt% low density polyethylene, based on the total weight of the respective layer. In some embodiments, each outer layer can include from 0 wt% to 50 wt%, from 0 wt% to 40 wt%, from 0 wt% to 35 wt%, from 5 wt% to 35 wt%, from 10 wt% to 35 wt%, or from 15 wt% to 35 wt% low density polyethylene, based on the total weight of the respective layer.

[0128] In embodiments, the outer layers of the multilayer films of the present disclosure can have a variety of thicknesses. The thickness of each outer layer can depend on a number of factors, including, for example, the composition of each outer layer, the desired processing properties of the multilayer film, and the like. In embodiments, each outer layer can have a thickness from 1 micrometer (pm or micrometer) to 40 pm. In embodiments, the thickness of each outer layer can be from 1 pm to 40 pm, from 1 pm to 30 pm, from 1 pm to 20 pm, from 1 pm to 10 pm, from 10 pm to 40 pm, from 10 pm to 30 pm, from 10 pm to 20 pm, from 20 pm to 40 pm, from 20 pm to 30 pm, or from 30 pm to 40 pm.

[0129] The thickness of each outer layer of the multilayer films disclosed herein can constitute from 5% to 20% of the total thickness of the multilayer film. In some embodiments, the thickness of each outer layer can constitute from 5% to 15%, from 5% to 10%, from 10% to 20%, from 10% to 15%, or from 15% to 20% of the total thickness of the multilayer film.

[0130] Subskin layer

[0131] As previously mentioned, the multilayer films of the present disclosure can include one or more sub-layers. As used herein, a sub-layer can refer to any layer positioned between the outer layers of the multilayer film. As used herein, a central sub-layer of a multilayer film can be referred to as an “intermediate layer” or a “core layer.” In various embodiments, each sub-layer can include one or more materials that impart improved dart and puncture properties to the multilayer film as compared to conventional multilayer films.

[0132] In embodiments including multiple sub-layers, each sub-layer can include the same material, or each sub-layer can include a different material. For example, in a five-layer film designated as A / B / C / D / E, layers (B) and (D) can include the same material or different materials. In a seven-layer film designated as A / B / C / D / E / F / G, one or more of layers (B), (C), (E), and (F) can include the same material or different materials. In a nine-layer film designated as A / B / C / D / E / F / G / H / I, one or more of layers (B), (C), (G), and (H) can include the same material or different materials.

[0133] In embodiments, at least one sub-layer can comprise a multimodal polyethylene composition described herein. In embodiments, a sub-layer comprising a multimodal polyethylene composition described herein can have a density from 0.870 g / cm3to 0.970 g / cm3 3 to 0.970 g / cm3 3polyethylene blend. In embodiments, the at least one subskin layer can include greater than 20 wt% of the multimodal polyethylene composition described herein, based on the total weight of the respective layer. In one or more embodiments, each subskin layer can include greater than 20 wt% of the multimodal polyethylene composition described herein, based on the total weight of the respective layer. In some embodiments, each subskin layer can include 30 wt% to 100 wt%, 50 wt% to 80 wt%, 50 wt% to 60 wt%, 60 wt% to 100 wt%, 60 wt% to 80 wt%, or 80 wt% to 100 wt% of the multimodal polyethylene composition described herein, based on the total weight of the respective layer.

[0134] In embodiments, each subskin layer can include LLDPE, HDPE, the multimodal polyethylene composition described herein, MDPE, LDPE, and combinations thereof. In some embodiments, a subskin layer that does not include the multimodal polyethylene composition described herein can include a polyethylene having a density of 0.870 g / cm 3 to 0.970 g / cm 3 .

[0135] In one or more embodiments, each skin layer can include a linear low density polyethylene (LLDPE) having a density of 0.905 g / cm 3 to 0.930 g / cm 3 . In another embodiment, the linear low density polyethylene can have a density of 0.905 g / cm 3 to 0.925 g / cm 3 , 0.905 g / cm 3 to 0.920 g / cm 3 , 0.905 g / cm 3 to 0.915 g / cm 3 , 0.905 g / cm 3 to 0.910 g / cm 3 , 0.910 g / cm 3 to 0.930 g / cm 3 , 0.910 g / cm 3 to 0.925 g / cm 3 , 0.910 g / cm 3 to 0.920 g / cm 3 , 0.910 g / cm 3 to 0.915 g / cm 3 , 0.915 g / cm 3 to 0.930 g / cm 3 , 0.915 g / cm 3 to 0.925 g / cm3 0.915 g / cm 3 to 0.920 g / cm 3 0.920 g / cm 3 to 0.930 g / cm 3 0.920 g / cm 3 to 0.925 g / cm 3 0.925 g / cm 3 to 0.930 g / cm 3 .

[0136] In one or more embodiments, each skin layer can include a linear low density polyethylene (LLDPE) having a melt index (I2) from 0.2 grams per 10 minutes (g / 10 min) to 6.0 g / 10 min when measured according to ASTM D1238. It is also contemplated that the melt index (I2) of the linear low density polyethylene can be from 0.2 g / 10 min to 5.5 g / 10 min, 0.2 g / 10 min to 5.0 g / 10 min, or 0.2 g / 10 min to 4.5 g / 10 min, 0.5 g / 10 min to 4.0 g / 10 min, 0.5 g / 10 min to 3.5 g / 10 min, 0.5 g / 10 min to 3.0 g / 10 min, 1.0 g / 10 min to 2.0 g / 10 min, 1.0 g / 10 min to 1.5 g / 10 min, or 1.5 g / 10 min to 2.0 g / 10 min.

[0137] According to embodiments, the linear low density polyethylene can have a molecular weight distribution, expressed as the ratio of weight average molecular weight to number average molecular weight (Mw / Mn), in the range of 3.5 to 5.5. In further embodiments, the linear low density polyethylene can have a molecular weight distribution in the range of 3.5 to 4.5 or 4.5 to 5.5.

[0138] According to one or more further embodiments, the linear low density polyethylene can have a zero shear viscosity ratio from 1.2 to 3.0 when measured according to the test methods described herein. In embodiments, the linear low density polyethylene can have a zero shear viscosity ratio from 1.2 to 2.5, 1.2 to 2.0, 2.0 to 3.0, 2.0 to 2.5, or 2.5 to 3.0.

[0139] Various processes for producing linear low density polyethylene are contemplated. For example, linear low density polyethylene resins can be prepared using Ziegler-Natta catalyst systems, resins prepared using single-site catalysts including, but not limited to, bis-metallocene catalysts and constrained geometry catalysts, and resins prepared using post-metallocene molecular catalysts. Linear low density polyethylene resins include linear, substantially linear, or heterogeneous polyethylene-based copolymers or homopolymers. Linear low density polyethylene resins can contain less long chain branching than LDPE and include substantially linear polyethylenes further defined in U.S. Patent No. 5,272,236, U.S. Patent No. 5,278,272, U.S. Patent No. 5,582,923, and U.S. Patent No. 5,733,155; uniformly branched linear ethylene polymer components such as those in U.S. Patent No. 3,645,992; non-uniformly branched ethylene polymers such as those prepared according to the process disclosed in U.S. Patent No. 4,076,698; and / or blends thereof (such as those disclosed in U.S. Patent No. 3,914,342 or U.S. Patent No. 5,854,045). Linear low density polyethylene resins can be prepared via gas phase, solution phase, or slurry polymerization, or any combination thereof, using any type of reactor or reactor configuration known in the art.

[0140] In one or more embodiments, each primary skin layer can include 0 wt.% to 80 wt.%, 0 wt.% to 60 wt.%, 0 wt.% to 40 wt.%, 0 wt.% to 20 wt.%, 20 wt.% to 80 wt.%, 20 wt.% to 60 wt.%, 20 wt.% to 40 wt.%, 40 wt.% to 80 wt.%, 40 wt.% to 60 wt.%, or 60 wt.% to 80 wt.% of LLDPE, based on the total weight of the respective layer.

[0141] In embodiments, each secondary skin layer can include a low density polyethylene (LDPE). In one or more embodiments, the low density polyethylene can have a melt index of 0.1 g / 10 min to 10.0 g / 10 min when measured according to ASTM D1238 at a load of 2.16 kg and a temperature of 190 °C. In embodiments, the low density polyethylene can have a melt index of 0.1 g / 10 min to 5.0 g / 10 min, or 0.5 g / 10 min to 5.0 g / 10 min, or 0.5 g / 10 min to 2.0 g / 10 min. In embodiments, the low density polyethylene can have a density of 0.916 g / cm3to 0.935 g / cm3when measured according to ASTM D792. In another embodiment, the low density polyethylene can have a density of 0.916 g / cm3to 0.925 g / cm3. 3 3 3 to 0.925 g / cm3.​​3 .

[0142] In one or more embodiments, each primary skin layer can include less than 50 wt% of LDPE, based on the total weight of the respective layer. In some embodiments, each secondary skin layer can include from 0 wt% to 50 wt%, from 0 wt% to 40 wt%, from 0 wt% to 35 wt%, from 5 wt% to 35 wt%, from 10 wt% to 35 wt%, or from 15 wt% to 35 wt% of LDPE, based on the total weight of the respective layer.

[0143] In one or more embodiments, each secondary skin layer can include MDPE. “MDPE” is typically prepared using chromium or Ziegler-Natta catalysts or using single-site catalysts, including but not limited to substituted mono- or bis-cyclopentadienyl catalysts (commonly referred to as metallocenes), constrained geometry catalysts, phosphinimine catalysts, and polyvalent catalyst aryloxyether catalysts (commonly referred to as bisphenylphenoxy). It should be noted that MDPE can be used in one or more secondary skin layers.

[0144] In one or more embodiments, each primary skin layer can include greater than 20 wt% of MDPE, based on the total weight of the respective layer. In some embodiments, each secondary skin layer can include from 30 wt% to 100 wt%, from 50 wt% to 80 wt%, from 50 wt% to 60 wt%, from 60 wt% to 100 wt%, from 60 wt% to 80 wt%, or from 80 wt% to 100 wt% of MDPE, based on the total weight of the respective layer.

[0145] In embodiments, each secondary skin layer can include a high density polyethylene (HDPE) having a density from 0.935 g / cm3to 0.980 g / cm3when measured according to ASTM D792. 3 In another embodiment, the HDPE can have a density from 0.935 g / cm3to 0.970 g / cm3. 3 In another embodiment, the HDPE can have a density from 0.935 g / cm3to 0.970 g / cm3. 3 In another embodiment, the HDPE can have a density from 0.935 g / cm3to 0.970 g / cm3. 3 In another embodiment, the HDPE can have a density from 0.935 g / cm3to 0.970 g / cm3. 3 In another embodiment, the HDPE can have a density from 0.935 g / cm3to 0.970 g / cm3. 3 In another embodiment, the HDPE can have a density from 0.935 g / cm3to 0.970 g / cm3. 3 In another embodiment, the HDPE can have a density from 0.935 g / cm3to 0.970 g / cm3. 3 In another embodiment, the HDPE can have a density from 0.935 g / cm3to 0.970 g / cm3. 3 In another embodiment, the HDPE can have a density from 0.935 g / cm3to 0.970 g / cm3. 3 In another embodiment, the HDPE can have a density from 0.935 g / cm3to 0.970 g / cm3. 3 In another embodiment, the HDPE can have a density from 0.935 g / cm3to 0.970 g / cm3. 3 In another embodiment, the HDPE can have a density from 0.935 g / cm3to 0.970 g / cm3. 3 In another embodiment, the HDPE can have a density from 0.935 g / cm3to 0.970 g / cm3. 3 In another embodiment, the HDPE can have a density from 0.935 g / cm3to 0.970 g / cm3. 3 ​3 0.940 g / cm 3 to 0.950 g / cm 3 0.950 g / cm 3 to 0.980 g / cm 3 0.950 g / cm 3 to 0.970 g / cm 3 0.950 g / cm 3 to 0.960 g / cm 3 0.960 g / cm 3 to 0.980 g / cm 3 0.960 g / cm 3 to 0.970 g / cm 3 0.970 g / cm 3 to 0.980 g / cm 3 .

[0146] In one or more embodiments, each primary skin layer can include HDPE having a melt index (I2) of 0.1 grams per 10 minutes (g / 10 min) to 10.0 g / 10 min when measured according to ASTM D1238 at a load of 2.16 kg and a temperature of 190 °C. It is also contemplated that the melt index (I2) of the high density polyethylene can be 0.1 g / 10 min to 5.0 g / 10 min, 0.1 g / 10 min to 1.0 g / 10 min, or 1.0 g / 10 min to 10.0 g / 10 min, 1.0 g / 10 min to 5.0 g / 10 min, or 5.0 g / 10 min to 10.0 g / 10 min.

[0147] Various methods are contemplated for producing the high density polyethylene. For example, the HDPE resin can be prepared using a Ziegler-Natta catalyst system, a chromium catalyst, or a single-site catalyst including, but not limited to, a bis-metallocene catalyst and a shape restricted catalyst.

[0148] In one or more embodiments, each primary skin layer can include up to 50 weight percent of HDPE, based on the total weight of the respective layer. In some embodiments, each secondary skin layer can include 0 weight percent to 90 weight percent, 15 weight percent to 80 weight percent, 15 weight percent to 50 weight percent, 20 weight percent to 50 weight percent, 30 weight percent to 40 weight percent, or 35 weight percent to 50 weight percent of HDPE, based on the total weight of the respective layer.

[0149] In embodiments, each subskin layer of the multilayer film of the present disclosure can have a variety of thicknesses. The thickness of each subskin layer can depend on a number of factors, including, for example, the composition of the subskin layer, the desired overall dart and puncture performance of the multilayer film, and the like. In embodiments, each subskin layer can have a thickness from 1 micrometer, pm, to 85 pm. In embodiments, each outer layer can have a thickness from 1 pm to 80 pm, 1 pm to 60 pm, 1 pm to 40 pm, 1 pm to 20 pm, 20 pm to 80 pm, 20 pm to 60 pm, 20 pm to 40 pm, 40 pm to 80 pm, 40 pm to 60 pm, or 60 pm to 80 pm.

[0150] When subskin layers are present in embodiments of the multilayer film, each subskin layer of the multilayer film disclosed herein can constitute from 5% to 40% of the total thickness of the multilayer film. In some embodiments, each subskin layer can constitute from 5% to 20 wt.%, 5% to 15%, 5% to 10%, 10% to 40%, 10% to 20%, 10% to 15%, 15% to 40%, 15% to 20%, or 20% to 40% of the total thickness of the multilayer film.

[0151] Barrier layer

[0152] In embodiments, the multilayer film can include a barrier layer. As used herein, the term “barrier layer” refers to a layer that reduces the diffusion of vapor or gas into or out of the multilayer film. For example, a barrier layer can reduce the diffusion of aroma, water, or oxygen into or out of the multilayer film.

[0153] In embodiments, the barrier layer can include a polar material. As used herein, the term “polar material” refers to a polymer formed from at least one monomer comprising at least one heteroatom. Some examples of heteroatoms include O, N, P, and S. In various embodiments, the polar material can be selected from an ethylene vinyl alcohol polymer (EVOH) (e.g., Eval H171B sold by Kuraray) or a combination of EVOH and polyamide (PA) (e.g., nylon 6, nylon 66, and nylon 6 / 66 sold by DuPont). In various embodiments, the barrier layer consists of ethylene vinyl alcohol (EVOH). In some embodiments, the barrier layer does not include polyamide or is substantially free of polyamide. As used herein, “substantially free of” can mean that the barrier layer includes less than 1 wt% of polyamide, based on the total weight of the barrier layer. In embodiments, the barrier layer can include less than 0.5 wt% or less than 0.1 wt% of polyamide. It will be appreciated that, in embodiments, the barrier layer including a polar material can include or consist of the polar material. In embodiments where the layer including a polar material includes the polar material, the polar material can be mixed with any polymer, including polyethylene, such as LLDPE, LDPE, ULDPE, MDPE, and the multimodal polyethylene compositions described herein. In various embodiments, the polar material has a melt index (I2) (2.16 kg, 190 °C) of 0.1 g / 10 min to 40 g / 10 min, 0.2 g / 10 min to 20 g / 10 min, or 0.5 g / 10 min to 10 g / 10 min. In various embodiments, the polar material has a density of 1.00 g / cm3to 1.30 g / cm3, or 1.10 g / cm3to 1.20 g / cm3(1 cm = 1 cc). 3 3 3 3 3 (1 cm

[0154] In embodiments, the barrier layer of the multilayer film of the present disclosure can have a variety of thicknesses. The thickness of the barrier layer can depend on a number of factors, including, for example, the composition of the barrier layer, the desired overall recyclability and barrier performance of the multilayer film, and the like. In embodiments, the thickness of the barrier layer can be 0.1 pm to 20 pm, 0.1 pm to 15 pm, 0.1 pm to 10 pm, 0.1 pm to 5 pm, 0.1 pm to 1 pm, 0.1 pm to 0.5 pm, 0.5 pm to 20 pm, 0.5 pm to 15 pm, 0.5 pm to 10 pm, 0.5 pm to 5 pm, 0.5 pm to 1 pm, 1 pm to 20 pm, 1 pm to 15 pm, 1 pm to 10 pm, 1 pm to 5 pm, 5 pm to 20 pm, 5 pm to 15 pm, 5 pm to 10 pm, 10 pm to 20 pm, 10 pm to 15 pm, or 15 pm to 20 pm. ​​​​

[0155] The thickness of the barrier layer of the multilayer film disclosed herein can comprise from 1% to 10%, from 1% to 8%, from 1% to 6%, from 1% to 4%, from 1% to 2%, from 2% to 10%, from 2% to 8%, from 2% to 6%, from 2% to 4%, from 4% to 10%, from 4% to 8%, from 4% to 6%, from 6% to 10%, from 6% to 8%, or from 8% to 10% of the total thickness of the multilayer film.

[0156] Tie layer

[0157] In embodiments, the multilayer film can include one or more tie layers. As used herein, the term “tie layer” refers to a layer that bonds two layers together. For example, a tie layer can bond a polar material to one or more layers that do not include a polar material. For example, a tie layer can be placed adjacent to a layer comprising a polar material to adhere the layer comprising a polar material to a layer comprising polyethylene. In embodiments, a tie layer can be placed adjacent to a barrier layer to adhere the barrier layer comprising a polar material to one or more layers comprising polyethylene, such as one or more subsurface layers or outer layers.

[0158] In embodiments, a variety of polymers known to those skilled in the art based on the teachings herein that can be used to adhere a layer comprising a polar material, such as, for example, EVOH or a polyamide, to a layer comprising polyethylene can be used in the tie layer.

[0159] In embodiments, the tie layer can comprise an ethylene and acid copolymer. In one or more embodiments, the tie layer can comprise an anhydride grafted ethylene / alpha-olefin interpolymer. As used herein, the term “anhydride grafted ethylene / alpha-olefin interpolymer” refers to an ethylene / alpha-olefin interpolymer comprising at least one anhydride group attached via a covalent bond. The anhydride grafted ethylene / alpha-olefin interpolymer can be an ethylene-based polymer to which an anhydride grafted monomer is grafted. Suitable ethylene-based polymers for low-solubility viscosity maleic anhydride grafted polyolefins include, but are not limited to, polyethylene homopolymers and copolymers with alpha-olefins, copolymers of ethylene with vinyl acetate, and copolymers of ethylene with one or more alkyl (meth)acrylates. In particular embodiments, the anhydride grafted ethylene / alpha-olefin interpolymer can comprise a maleic anhydride grafted linear low density polyethylene (LLDPE).

[0160] In one or more embodiments, the anhydride grafted ethylene / a-olefin interpolymer includes up to 10 wt%, up to 5 wt%, or 1 to 4 wt% of maleic anhydride grafted monomers, based on the total weight of the anhydride grafted ethylene / a-olefin interpolymer. The weight percent of the ethylene-based polymer is complementary to the amount of maleic anhydride grafted monomers such that the sum of the weight percent of the ethylene-based polymer and the maleic anhydride grafted monomers is 100 wt%. Thus, the anhydride grafted ethylene / a-olefin interpolymer includes up to 90 wt%, up to 95 wt%, or 96 to 99 wt% of the ethylene-based polymer, based on the total weight of the maleic anhydride grafted polyolefin.

[0161] Examples of anhydride grafting moieties can include, but are not limited to, maleic anhydride, citraconic anhydride, 2-methylmaleic anhydride, 2-chloromaleic anhydride, 2,3-dimethylmaleic anhydride, bicyclo[2,2,1]-5-heptene-2,3-dicarboxylic anhydride, and 4-methyl-4-cyclohexene-1,2-dicarboxylic anhydride, bicyclo(2.2.2)oct-5-ene-2,3-dicarboxylic anhydride, o-octahydronaphthalene-2,3-dicarboxylic anhydride, 2-oxa-1,3-diketospiro(4.4)non-7-ene, bicyclo(2.2.1 )hept-5-ene-2,3-dicarboxylic anhydride, tetrahydrophthalic anhydride, norborn-5-ene-2,3-dicarboxylic anhydride, nadic anhydride, methyl nadic anhydride, norbornenedioic anhydride, methyl norbornenedioic anhydride, and x-methyl-bicyclo(2.2.1 )hept-5-ene-2,3-dicarboxylic anhydride. In one embodiment, the anhydride grafting moiety comprises maleic anhydride.

[0162] In further embodiments, the anhydride grafted ethylene / a-olefin interpolymer has a density of less than 0.940 grams per cubic centimeter (g / cm3), as measured according to ASTM Method No. D792-91, or from 0.855 g / cm3to 0.940 g / cm3. 3 ), or 0.855 g / cm 3 to 0.940 g / cm 3 . Other density ranges can be from 0.855 g / cm 3 to 0.900 g / cm 3 , from 0.855 g / cm 3 to 0.880 g / cm 3 , from 0.855 g / cm 3 to 0.860 g / cm 3 , from 0.860 g / cm 3 to 0.940 g / cm 3 , from 0.860 g / cm 3 to 0.910 g / cm 3 , from 0.860 g / cm 3 to 0.880 g / cm 3 , from 0.880 g / cm 3to 0.910 g / cm 3 , or 0.880 g / cm 3 to 0.900 g / cm 3 .

[0163] In one or more embodiments, the anhydride grafted ethylene / alpha-olefin interpolymer can have a melt index (I2) of 300 grams / 10 minutes (g / 10 min) to 1500 g / 10 min, or 300 g / 10 min to 1000 g / 10 min, 500 a / 10 min to 800 g / 10 min, 500 g / 10 min to 600 g / 10 min, 600 g / 10 min to 1000 g / 10 min, 600 g / 10 min to 800 g / 10 min, or 800 g / 10 min to 1000 g / 10 min, as measured according to ASTM Method D1238 at 190 °C and 2.16 kg.

[0164] In one or more embodiments, the anhydride grafted ethylene / alpha-olefin interpolymer can have a melt viscosity of less than 200,000 cP when measured at 177 °C according to the test method subsequently described in the disclosure. In embodiments, the anhydride grafted ethylene / alpha-olefin interpolymer can have a melt viscosity of 2,000 cP to 200,000 cP, 2,000 cP to 100,000 cP, 2,000 cP to 50,000 cP, 2,000 cP to 10,000 cP, 10,000 cP to 200,000 cP, 10,000 cP to 100,000 cP, 10,000 cP to 50,000 cP, 50,000 cP to 200,000 cP, 50,000 cP to 100,000 cP, or 100,000 cP to 200,000 cP when measured at 177 °C according to the test method subsequently described in the disclosure.

[0165] Various commercial embodiments are considered suitable. For example, suitable anhydride grafted ethylene / alpha-olefin interpolymers are commercially available from The Dow Chemical Company under the trademark DOWLEX®. 41E710.

[0166] Various amounts of the ethylene and acid copolymer or anhydride grafted ethylene / alpha-olefin interpolymer are contemplated as suitable in the tie layer of the multilayer film described herein. In some embodiments, the tie layer can include 20 wt% or less of the ethylene and acid copolymer or anhydride grafted ethylene / alpha-olefin interpolymer, based on the total weight of the tie layer. In some embodiments, the tie layer can include from 5 wt% to 15 wt% or from 10 wt% to 15 wt% of the ethylene and acid copolymer or anhydride grafted ethylene / alpha-olefin interpolymer, based on the total weight of the tie layer. The remainder of the tie layer can be a polyethylene, such as an LDPE, an HDPE, an MDPE, or a multimodal polyethylene composition described herein.

[0167] Without being bound by theory, it is believed that the anhydride grafted ethylene / alpha-olefin interpolymer can be placed adjacent to a layer comprising a polar material to bind the layer comprising a polar material to a non-polar layer. In embodiments, the tie layer can be placed in direct contact with the layer comprising a polar material. In embodiments, the tie layer can be placed between and in direct contact with a layer comprising a polar material and a layer comprising a multimodal polyethylene composition described herein.

[0168] In embodiments, each tie layer of the multilayer film of the present disclosure can have a variety of thicknesses. The thickness of each tie layer can depend on a number of factors, including, for example, the adhesion properties of the tie layer. In embodiments, each tie layer can have a thickness from 0.1 pm to 20 pm. In embodiments, the thickness of each tie layer can be from 0.1 pm to 15 pm, from 0.1 pm to 10 pm, from 0.1 pm to 5 pm, from 0.1 pm to 1 pm, from 0.1 pm to 0.5 pm, from 0.5 pm to 20 pm, from 0.5 pm to 15 pm, from 0.5 pm to 10 pm, from 0.5 pm to 5 pm, from 0.5 pm to 1 pm, from 1 pm to 20 pm, from 1 pm to 15 pm, from 1 pm to 10 pm, from 1 pm to 5 pm, from 5 pm to 20 pm, from 5 pm to 15 pm, from 5 pm to 10 pm, from 10 pm to 20 pm, from 10 pm to 15 pm, or from 15 pm to 20 pm.

[0169] The thickness of each tie layer of the multilayer film disclosed herein can comprise from 1% to 10%, from 1% to 8%, from 1% to 6%, from 1% to 4%, from 1% to 2%, from 2% to 10%, from 2% to 8%, from 2% to 6%, from 2% to 4%, from 4% to 10%, from 4% to 8%, from 4% to 6%, from 6% to 10%, from 6% to 8%, or from 8% to 10% of the total thickness of the multilayer film.

[0170] Method of producing the films described in the present invention

[0171] Various methods are contemplated for producing the multilayer film. In one or more embodiments, the method of manufacturing the multilayer film can include cast film extrusion or blown film extrusion.

[0172] In some embodiments, the method of manufacturing a multilayer film can include forming a blown film bubble. In some embodiments, the blown film bubble can be a multilayer blown film bubble. Further in accordance with this embodiment, the multilayer blown film bubble can include at least two, three, five, seven, nine, or more layers, and the layers can be adhered to one another.

[0173] During embodiments of the blown film process, an extruded film from the extruder die can be formed and pulled up a tower onto a nip. The film can then be wound onto a core. Prior to winding the film onto the core, the ends of the film can be cut and folded using a folding apparatus. This can make it difficult to separate the layers of the film, which can be important for shipping applications (generally) or heavy duty shipping bag applications.

[0174] In other embodiments, the blown film bubble can be formed by a blown film extrusion line having a length to diameter ratio (“L / D”) of 30 to 1. In some embodiments, the extrusion line can have a blow up ratio of 1 to 5, 1 to 3, 2 to 5, or 2 to 3. In some embodiments, the extrusion line can utilize a die having internal bubble cooling. In some embodiments, the die gap can be 1 millimeter (mm) to 5 mm, 1 mm to 3 mm, 2 mm to 5 mm, or 2 mm to 3 mm.

[0175] In some embodiments, the extrusion line can utilize a film thickness gauge. In some embodiments, the multilayer film thickness can be maintained at 15 pm or to 115 pm during the extrusion process. In embodiments, the multilayer film thickness can be maintained at 15 pm to 100 pm, 15 pm to 75 pm, 15 pm to 50 pm, 15 pm to 25 pm, 25 pm to 115 pm, 25 pm to 100 pm, 25 pm to 75 pm, 25 pm to 50 pm, 50 pm to 115 pm, 50 pm to 100 pm, 50 pm to 75 pm, 75 pm to 115 pm, 75 pm to 100 pm, or 100 pm to 115 pm.

[0176] In some embodiments, the forming of the multilayer film blown film bubble step can occur at a temperature of 350°F to 500°F, or 375°F to 475°F. The output speed can be 5 lb / hr / in to 25 lb / hr / in, 5 lb / hr / in to 20 lb / hr / in, 5 lb / hr / in to 15 lb / hr / in, 5 lb / hr / in to 10 lb / hr / in, 10 lb / hr / in to 25 lb / hr / in, 10 lb / hr / in to 20 lb / hr / in, 10 lb / hr / in to 15 lb / hr / in, 15 lb / hr / in to 25 lb / hr / in, 15 lb / hr / in to 20 lb / hr / in, or 20 lb / hr / in to 25 lb / hr / in.

[0177] Article

[0178] Embodiments of the present disclosure also relate to articles, such as packages, formed from the multilayer films of the present disclosure. Such packages can be formed from any of the multilayer films of the present disclosure described herein. The multilayer films of the present disclosure are particularly useful in articles requiring good puncture properties.

[0179] Examples of such articles can include flexible packages, pouches, stand-up pouches, and pre-made packages or pouches.

[0180] Various methods of producing embodiments of articles from the multilayer films disclosed herein will be familiar to one of ordinary skill in the art.

[0181] Test methods

[0182] Test methods include the following:

[0183] Melt index

[0184] Melt indices I2(or I2) and I10of polymer samples 10 (or 110) are measured according to ASTM D-1238 at 190°C and under 2.16 kg and 10 kg loads, respectively. Their values are reported in g / 10 min. The fractions of polymer samples are measured by collecting the product polymer from a reactor that produces a particular fraction or portion of the polymer composition. For example, a first polyethylene fraction can be collected from a reactor, thereby producing a lower density, higher molecular weight component of the polymer composition. The polymer solution is dried under vacuum prior to melt index measurements.

[0185] Density

[0186] Samples for density measurement were prepared according to ASTM D4703. Measurements were made within one hour of pressing the sample according to ASTM D792, Method B.

[0187] ASTM D1709 dart drop

[0188] The Falling Dart Test determines the energy that causes a plastic film to fail under the influence of a freely falling dart under specified impact conditions. The test result is expressed in the weight of the projectile that falls from a specified height that will cause 50% of the samples tested to fail.

[0189] After the film was produced, the film was conditioned at 23°C (+ / - 2°C) and 50% R.H (+ / - 5) for at least 40 hours according to ASTM standards. The standard test conditions were 23°C (+ / - 2°C) and 50% R.H (+ / - 5) according to ASTM standards.

[0190] The test results were reported by Method B, which uses a 2" diameter dart head and a 60" drop height. The sample thickness at the center of the sample was measured and then the sample was clamped by a ring-shaped sample holder with an internal diameter of 5 inches. The dart was loaded above the center of the sample and released by a pneumatic or electromagnetic mechanism.

[0191] The test was performed according to the 'Staircase' method. If the sample failed, a new sample was tested with a known and fixed decrease in the weight of the dart. If the sample did not fail, a new sample was tested with a known increase in the weight of the dart. After 20 samples were tested, the number of failures was determined. If this number was 10, the test was complete. If the number was less than 10, the test continued until 10 failures were recorded. If the number was greater than 10, the test continued until the sum of the non-failures was 10. From these data, the dart impact strength was determined according to ASTM D1709 and expressed as a Type B dart impact in grams.

[0192] Instrumented dart drop impact

[0193] The Instrumented Dart Impact method was measured according to ASTM D7192 using an Instron CEAST 9350 impact tester on plastic film samples. The test was performed using a 12.7 mm diameter round head with a hemispherical head, a 75 mm diameter clamping assembly with rubber faced grips. The instrument was equipped with an environmental chamber for testing at low or high temperatures. The typical specimen size was 125 mm x 125 mm. The standard test speed was 200 m / min. The film thickness was 2 mils.

[0194] Creep zero shear viscosity measurement method

[0195] Zero-shear viscosity was obtained by creep test, which was performed on an AR-G2 stress controlled rheometer (TA Instruments; New Castle, Del) using 25 mm diameter parallel plates at 190 °C. The rheometer oven was set to the test temperature for at least 30 minutes before zeroing the fixtures. At the test temperature, a compression molded sample disk was inserted between the plates and allowed to come to equilibrium for 5 minutes. The upper plate was then lowered to 50 pm above the desired test gap (1.5 mm). Any excess material was trimmed off and the upper plate was lowered to the desired gap. The measurement was conducted under a nitrogen purge at a flow rate of 5 L / min. The default creep time was set to 2 hours.

[0196] A constant low shear stress of 20 Pa was applied to all samples to ensure that the steady state shear rate was low enough to be in the Newtonian region. For the samples in this study, the resulting steady state shear rate was in the range of 10 -3 to 10 -4 s -1 The steady state was determined by linear regression of all data in 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 was greater than 0.97, then steady state was considered to have been reached and the creep test was stopped. In all cases for this study, the slope met the stated criteria within 2 hours. The steady state shear rate was determined from the slope of the linear regression of all data points in the last 10% time window of a plot of e vs. t, where e is the strain. The zero-shear viscosity was determined from the ratio of the applied stress to the steady state shear rate.

[0197] To determine if the sample had degraded during the creep test, a small amplitude oscillatory shear test was performed on the same sample before and after the creep test from 0.1 to 100 rad / s. The complex viscosity values of the two tests were compared. If the difference in viscosity values was greater than 5% at 0.1 rad / s, then the sample was considered to have degraded during the creep test and the results were discarded.

[0198] Gel permeation chromatography (GPC)

[0199] The chromatographic system consisted of a PolymerChar GPC-IR (PolymerChar, Valencia, Spain) high temperature GPC instrument equipped with an internal IR5 infrared detector (IR5). The auto-sampler oven compartment was set to 160 degrees Celsius and the column compartment was set to 150 degrees Celsius. The columns used were 4 Agilent "Mixed A" 30 cm 20-micron linear mixed bed columns and a 20-um pre-column. The chromatographic solvent used was 1,2,4 Trichlorobenzene with 200 ppm of butylated hydroxy toluene (BHT) and was nitrogen sparged. The solvent source was nitrogen sparged. The injection volume used was 200 microliters and the flow rate was 1.0 milliliters / minute.

[0200] The GPC column set was calibrated by using 21 narrow molecular weight distribution polystyrene standards ranged from 580 to 8,400,000 molecular weight and arranged in six "cocktail" mixtures with at least a decade of separation between individual molecular weights. The standards were purchased from Agilent Technologies. For molecular weights equal to or greater than 1,000,000, 0.025 grams of polystyrene standard was prepared in 50 milliliters of solvent and for molecular weights less than 1,000,000, 0.05 grams of polystyrene standard was prepared in 50 milliliters of solvent. The polystyrene standards were dissolved and gently stirred for 30 minutes at 80 degrees Celsius. The polystyrene standard peak molecular weights were converted to polyethylene molecular weights using Equation 1 (as described in Williams and Ward, J. Polym. Sci., Polym. Let., Vol. 6, p. 621 (1968)):

[0201] M 聚乙烯 = A x (M 聚苯乙烯 ) B (EQ 1)

[0202] where M is the molecular weight, A has a value of 0.4315, and B is equal to 1.0.

[0203] A fifth order polynomial was used to fit the calibration points for the corresponding polyethylene equivalent. A small adjustment to A (approximately 0.375 to 0.445) was made to correct for column resolution and band broadening effects so that a linear homopolymer polyethylene standard was obtained at 120,000 Mw.

[0204] The GPC column set was calibrated by using 21 narrow molecular weight distribution polystyrene standards ranged from 580 to 8,400,000 molecular weight and arranged in six "cocktail" mixtures with at least a decade of separation between individual molecular weights. The standards were purchased from Agilent Technologies. For molecular weights equal to or greater than 1,000,000, 0.025 grams of polystyrene standard was prepared in 50 milliliters of solvent and for molecular weights less than 1,000,000, 0.05 grams of polystyrene standard was prepared in 50 milliliters of solvent. The polystyrene standards were dissolved and gently stirred for 30 minutes at 80 degrees Celsius. The polystyrene standard peak molecular weights were converted to polyethylene molecular weights using Equation 1 (as described in Williams and Ward, J. Polym. Sci., Polym. Let., Vol. 6, p. 621 (1968)):

[0205]

[0206] wherein Rvis the retention volume in milliliters, the peak width is in milliliters, the peak maximum is the maximum height of the peak, and the ½ height is the ½ height of the peak maximum.

[0207]

[0208] wherein Rvis the retention volume in milliliters, and the peak width is in milliliters, the peak maximum is the maximum position of the peak, the 10th height is the 1 / 10th height of the peak maximum, and wherein the trailing peak refers to the tail of the peak later than the peak maximum in retention volume, and wherein the leading peak refers to the front of the peak earlier than the peak maximum in retention volume. The plate count of the chromatographic system should be greater than 18,000, and the symmetry should be between 0.98 and 1.22.

[0209] The samples were prepared in a semi-automated fashion using PolymerChar "Instrument Control" software, where the target weight of the sample was set to 2 mg / ml, and the solvent (containing 200 ppm BHT) was added by a PolymerChar high temperature auto-sampler into a septum capped vial that was previously bubbled with nitrogen. The samples were allowed to dissolve at 160 degrees Celsius for 2 hours with "low speed" shaking.

[0210] Based on the GPC results, the Mn, Mw, and Mz TM were calculated using the PolymerChar GPC-One software, the baseline-subtracted IR chromatogram at each equidistant data collection point (i), and the polyethylene equivalent molecular weight from the narrow standard calibration curve at point (i) according to Equations 4-6. (GPC) (GPC) (GPC)

[0211]

[0212]

[0213]

[0214] ​​​To monitor the changing bias over time, a flow rate marker (decane) was introduced into each sample via a micro-pump controlled with the PolymerChar GPC-IR system. This flow rate marker (FM) was used to linearly correct the pump flow rate of each sample (flow rate (nominal)) by comparing the RV of the corresponding decane peak within the sample (RV(FM sample)) to the RV of the alkane peak within the narrow standard calibration (RV(FM calibrated)). Then, any change in the decane marker peak time was assumed to be related to a linear change in the flow rate over the course of the run (flow rate (effective)). To promote the highest accuracy in the RV measurement of the flow marker peak, a least squares fitting routine was used to fit the peak of the flow marker concentration chromatogram into a quadratic equation. Then, the first derivative of the quadratic equation was used to solve for the true peak position. After calibrating the system based on the flow marker peak, the effective flow rate (relative to the narrow standard calibration) was calculated as Equation 7. The processing of the flow marker peak was done by the PolymerChar GPCOne TM software. An acceptable flow rate correction is such that the effective flow rate should be within + / - 0.5% of the nominal flow rate.

[0215] Flow rate (effective) = Flow rate (nominal) * (RV(FM calibrated) / RV(FM sample)) (EQ 7)

[0216] Improved comonomer content analysis method (iCCD)

[0217] An improved method for comonomer content analysis (iCCD) was developed in 2015 (Cong and Parrott et al., WO2017040127A1). The iCCD test was performed with a Crystallization Elution Fractionation instrument (CEF) (PolymerChar, Spain) equipped with an IR-5 detector (PolymerChar, Spain) and a two-angle light scattering detector model 2040 (Precision Detectors, now Agilent Technologies). A 5 cm or 10 cm (length) X ¼” (ID) stainless steel guard column packed with 20-27 micron glass (MoSCi Corporation, USA) was installed just before the IR-5 detector in the detector oven. Ortho-dichlorobenzene (ODCB, 99% anhydrous grade or technical grade) was used. Silica gel 40 (particle size 0.2-0.5 mm, catalog number 10181-3) was obtained from EMD Chemicals (previously used to dry ODCB solvent). The CEF instrument was equipped with an autosampler with N2purge function. ODCB was bubbled with dry nitrogen (N2) for one hour before use. Sample preparation was performed with the autosampler at a concentration of 4 mg / ml (unless otherwise specified) at 160 °C for 1 hour with shaking. The injection volume was 300 μΐ. The temperature profile for iCCD was: crystallization from 105 °C to 30 °C at 3 °C / min, thermal equilibration at 30 °C for 2 minutes (including solubles fraction elution time set to 2 minutes), elution from 30 °C to 140 °C at 3 °C / min. The flow rate during crystallization was 0.0 milliliter / minute. The flow rate during elution was 0.50 ml / min. Data were collected at one data point per second.

[0218] The iCCD column was packed with Bright 7GNM8-NiS (Nippon Chemical Industrial Co.) in a 15 cm (length) X ¼” (ID) stainless steel tube. The column packing and conditioning were performed according to the reference (Cong, R.; Parrott, A.; Hollis, C; Cheatham, M. WO2017040127A1) with slurry method. The final pressure of the TCB slurry packing was 150 bar.

[0219] Column temperature calibration was performed by using a mixture of a reference material linear homopolymer polyethylene (with zero comonomer content, melt index (I2) of 1.0, polydispersity Mw / Mn of about 2.6 by conventional gel permeation chromatography, 1.0 mg / ml) with eicosane (2 mg / ml) in ODCB. The iCCD temperature calibration consisted of four steps: (1) calculation of a delay volume, which was defined as the measured peak elution temperature of eicosane minus a temperature offset between 30.00 °C; (2) subtraction of the temperature offset of the elution temperature from the iCCD raw temperature data. It should be noted that this temperature offset is a function of experimental conditions, such as elution temperature, elution flow rate, etc.; (3) creation of a linear calibration line, converting the elution temperature in the range of 30.00 °C to 140.00 °C such that the linear homopolymer polyethylene reference had a peak temperature at 101.0 °C and eicosane had a peak temperature at 30.0 °C; (4) linear extrapolation of the elution temperature below 30.0 °C according to the reference (Cerk and Cong et al., US 9,688,795) by using an elution heating rate of 3 °C / minute for the soluble fraction measured isothermally at 30 °C.

[0220] A comonomer content versus elution temperature relationship for the iCCD was constructed by using 12 reference materials (ethylene homopolymers and ethylene-octene random copolymers made with single-site metallocene catalysts with ethylene equivalent weight average molecular weights in the range of 35,000 to 128,000). All of these reference materials were analyzed in the same manner as the previously specified 4 mg / mL. The reported elution peak temperatures were linearly fit to the linear equation y = -6.3515x + 101.00, where y represents the elution temperature of the iCCD and x represents the octene mole %, and R 2 was 0.978.

[0221] The molecular weight of the polymer and the molecular weight of the polymer fractions were determined directly from the LS detector (90 degree angle) and the concentration detector (IR-5) according to the Rayleigh-Gans-Debys approximation (Striegel and Yau, Modern Size Exclusion Liquid Chromatogram, pages 242 and 263) by assuming a shape factor of 1 and all virial coefficients equal to zero. The integration window was set to integrate the entire chromatogram in the elution temperature (temperature calibration specified above) range of 23.0 °C to 120 °C.

[0222] The molecular weight (Mw) was calculated from the iCCD including the following four steps:

[0223] (1) Measure the bias between the detectors. Bias is defined as the geometric volume bias between the LS detector relative to the concentration detector. It is calculated as the difference in elution volume (mL) of the polymer peak between the concentration detector and the LS chromatogram. This is converted to a temperature bias by using the elution heating rate and the elution flow rate. Linear high density polyethylene (comonomer content of zero, melt index (I2) of 1.0, polydispersity Mw / Mn of 7.0 by conventional gel permeation chromatography) is used as the reference material. The sample is run at 140 °C. The sample concentration is 1.0 mg / ml. The flow rate during crystallization is 0.0 mL / min. The flow rate during elution is 0.80 mL / min. The elution temperature range is from 140 °C to 142 °C at a rate of 3 °C / min. The elution time is 7 minutes. The sample is run in duplicate. The average of the two runs is used to calculate the bias. w / M n The bias is approximately 2.6 °C. The same experimental conditions as the normal iCCD method described above are used, except for the following parameters: crystallize from 140 °C to 137 °C at 10 °C / min, thermal equilibration at 137 °C for 1 minute as the soluble fraction elution time, soluble fraction (SF) time of 7 minutes, elute from 137 °C to 142 °C at 3 °C / min. The flow rate during crystallization is 0.0 mL / min. The flow rate during elution is 0.80 mL / min. The sample concentration is 1.0 mg / ml.

[0224] (2) Prior to integration, each LS data point in the LS chromatogram is shifted to correct for the inter-detector bias.

[0225] (3) The LS and concentration chromatograms are integrated over the entire elution temperature range with the baseline subtracted from step (1). The MW detector constant is calculated by using known MW HDPE samples in the range of 100,000 to 140,000 Mw and the area ratio of the LS and concentration integrated signals.

[0226] (4) The Mw of the polymer is calculated by using the ratio of the integrated light scattering detector (90 degree angle) to the concentration detector and using the MW detector constant.

[0227] The calculation of the half-height width is defined as the temperature difference between the front temperature and the back temperature at half the maximum peak height, searching forward from 35.0 °C for the front temperature at half the maximum peak and searching backward from 119.0 °C for the back temperature at half the maximum peak.

[0228] Zero shear viscosity ratio (ZSVR)

[0229] ZSVR is defined as the ratio of the zero shear viscosity (ZSV) of the branched polyethylene material to the ZSV of the linear polyethylene material at the equivalent weight average molecular weight (Mw-gpc) according to the following equations (EQ) 8 and 9:

[0230]

[0231]

[0232] ZSV values were obtained from the creep test at 190°C by the method described above. Mw-gpc values were determined from the conventional GPC method (Equation 5 in the Conventional GPC Method Description). A correlation between ZSV and its Mw-gpc for linear polyethylene was established based on a series of linear polyethylene reference materials. A description of the ZSV-Mw relationship can be found in the following literature, ANTEC Conference: Karjala, Teresa P., Sammler, Robert L., Mangnus, Marc A., Hazlitt, Lonnie G., Johnson, Mark S., Hagen, Charles M. Jr., Huang, Joe W. L., Reichek, Kenneth N., "Detection of low levels of long-chain branching in polyolefins," Annual Technical Conference - Society of Plastics Engineers (2008), Vol. 66, pp. 887-891.

[0233] MD tear

[0234] MD tear was measured according to ASTM D-1922. The force in grams required to propagate a tear across a film sample was measured using an Elmendorf tear strength tester. A pendulum, acting through the force of gravity, swings in an arc, thereby tearing the sample from a pre-cut slit. The tear propagates in the cross direction. The samples were conditioned at temperature for at least 40 hours prior to testing

[0235] Dynamic rheology analysis

[0236] To characterize the rheological behavior of substantially linear ethylene polymers, S. Lai and G. W. Knight introduced (ANTEC '93 Proceedings, Insite (TM) Technology Polyolefins (ITP) - New Rules in the Structure / Rheology Relations of Ethylene &-01erin Copolymers, New Orleans, La., May 1993) a new rheological measurement, the Dow Rheology Index (DRI), which represents the "normalized relaxation time of a polymer as a result of long chain branching." S. Lai et al. (ANTEC '94, Dow Rheology Index (DRI) for Insite (TM) Technology Polyolefins (ITP): Unique structure-Processing Relationships, pp. 1814-1815) defined the DRI to the extent that the rheology of ethylene-octene copolymers, which incorporate long chain branches into the polymer backbone, known as ITP (Insite (TM) Technology Polyolefins) deviates from conventional linear homogenous polyethylene, which is reported to have no long chain branching (LCB) by the following normalization equation:

[0237] DRI = [3650000 x (τ0 / η0)1] / 10 (EQ 10)

[0238] where τ0is the characteristic relaxation time of the material, and η0is the zero shear rate complex viscosity of the material. The DRI is calculated by least squares fitting the rheological curve described in U.S. Patent No. 6,114,486 (dynamic complex viscosity η*(ω) versus applied frequency (ω), e.g., 0.01-100 rad / sec) using the following generalized cross equation, i.e.

[0239] η*(ω) = η0 / [1 + (ω·τ0) n ] (EQ 11)

[0240] where n is the power law index of the material, η*(ω) and ω are the measured complex viscosity and applied frequency data, respectively.

[0241] Dynamic rheological measurements were performed in dynamic mode on a dynamic rheometer (e.g., TA Instruments ARES Rheometer) with 25 mm diameter parallel plates under inert atmosphere according to ASTM D4440. For all experiments, the rheometer was thermally stabilized at 190 °C for at least 30 minutes, then the appropriately stabilized (with antioxidant additives) compression molded sample was inserted onto the parallel plates. The plates were then closed with the instrument recording the normal force to ensure good contact. After about 5 minutes at 190 °C, the plates were gently compressed and excess polymer was trimmed from the plate periphery. The thermal stabilization was allowed to continue for an additional 10 minutes and the normal force was decreased back to zero. That is, all measurements were made after the sample was equilibrated at 190 °C for about 15 minutes and run under full nitrogen protection.

[0242] Two strain sweep (SS) experiments were initially performed at 190 °C to determine the linear viscoelastic strain that would produce a torque signal greater than 10% of the lower scale of the sensor over a full frequency (e.g., 0.01 to 100 rad / s) range. The first SS experiment was performed at a low applied frequency of 0.1 rad / s. This test was used to determine the sensitivity of the torque at low frequencies. The second SS experiment was performed at a high applied frequency of 100 rad / s. This ensured that the applied strain chosen was well within the linear viscoelastic region of the polymer so that the oscillatory rheological measurements would not induce structural changes in the polymer during the test. Additionally, a time sweep (TS) experiment was performed at the selected strain (determined from the SS experiments) at a low applied frequency of 0.1 rad / s to check the stability of the sample during the test.

[0243] The values of the storage (or elastic) modulus, loss (or viscous) modulus (G”), complex modulus (G*), complex viscosity (h*), and tan delta (ratio of loss modulus to storage modulus, G’ / G’) were obtained as a function of frequency (w) at a given temperature (e.g., 190 °C).

[0244] ASTM D1922 MD (machine direction) and CD (cross direction) B type Elmendorf tear

[0245] The Elmendorf tear test determines the average force to propagate a tear through a specified length of plastic film or non-rigid sheet after the tear has started using an Elmendorf-type tear tester.

[0246] After the film was produced from the sample to be tested, the film was conditioned at 23 °C (+ / - 2 °C) and 50% R.H (+ / - 5) for at least 40 hours according to ASTM standards. The standard test conditions were 23 °C (+ / - 2 °C) and 50% R.H (+ / - 5) according to ASTM standards.

[0247] The force (in grams) required to propagate a tear across a film or sheet sample was measured using a precisely calibrated pendulum apparatus. In the test, a pendulum swings in an arc under the force of gravity, tearing the sample from a pre-cut slit. One side of the sample is fixed by the pendulum and the other side is fixed by a stationary member. The loss of energy of the pendulum is indicated by a needle or an electronic scale. The scale indicates a function of the force required to tear the sample.

[0248] The sample test geometry used in the Elmendorf tear test is the 'constant radius geometry' specified in ASTM D1922. The test is typically performed on samples cut from films in both the MD and CD directions. The thickness of the film sample is measured at the center of the sample prior to testing. A total of 15 samples are tested in each film direction and the average tear strength and average thickness are reported. The average tear strength is normalized to the average thickness.

[0249] ASTM D882 MD and CD, 1% and 2% secant modulus

[0250] The film MD (machine direction) and CD (cross direction) secant modulus is determined according to ASTM D882. The reported secant modulus values are the average of five measurements.

[0251] Puncture strength

[0252] The puncture test determines the resistance of a film to penetration by a probe at a standard low rate, single test speed. The puncture test method is based on ASTM D5748. After the film is produced, the film is conditioned at 23 °C (+ / - 2 °C) and 50% R.H (+ / - 5) for at least 40 hours in accordance with the ASTM standard. The standard test conditions are 23 °C (+ / - 2 °C) and 50% R.H (+ / - 5) in accordance with the ASTM standard. The puncture is measured on a tensile testing machine. A square sample is cut from the sheet material to be 6 inches by 6 inches in size. The sample is clamped in a 4 inch diameter circular sample holder and the puncture probe is pushed into the center of the clamped film at a crosshead speed of 10 inches / minute. The internal test method follows ASTM D5748 with one modification. It differs from the ASTM D5748 method in that the probe used is a “0.5 inch diameter” polished steel ball on a “0.25 inch” support rod (rather than the 0.75 inch diameter pear shaped probe specified in D5748).

[0253] The maximum travel length is “7.7 inches” to prevent damage to the test fixture. There is no gauge length; the probe should be as close to the sample as possible without touching the sample prior to testing. A single thickness measurement is made at the center of the sample. For each sample, the maximum force, break force, penetration distance, and break energy are determined. A total of five samples are tested to determine the average puncture values. A “Kim-wipe” is used to clean the puncture probe after each sample.

[0254] Examples

[0255] The following examples illustrate features of the present disclosure, but are not intended to limit the scope of the present disclosure. The following experiments analyze the performance of embodiments of the multimodal polyethylene compositions described herein.

[0256] Example 1 : Preparation of multimodal polyethylene composition 1

[0257] The multimodal polyethylene composition 1 described according to one or more embodiments described in detail is prepared by the methods described below and utilizing the catalyst and reactors.

[0258] Ethylene-1-octene bimodal copolymer samples were produced in a tandem dual reactor configuration such as the one depicted in Figure 2 To prepare the samples, the first reactor was a continuous stirred tank reactor (CSTR) and the second reactor was a loop reactor (LR). Each reactor feed included recycled solvent (consisting of Isopar E, ethylene, 1-octene, and hydrogen) as well as fresh ethylene, 1-octene, and hydrogen. Recycled solvent, ethylene, and 1-octene were measured using industrial standard coriolis meter technology and hydrogen flow was measured using industrial standard thermal mass flow meters. Industrial standard rising stem plug valves were used to control the flow of each reactor feed component. A proprietary digital control system (DCS) automatically manipulated the position of each rising stem plug valve to control the mass flow of each reactant at its target value.

[0259] Recycle solvent pressure was delivered to each reactor using single, industry standard, positive displacement pump technology. Recycle solvent was metered into each reactor to maintain the Isopar E to polymer production ratio shown in the table below. Ethylene pressure was delivered using industry standard gas compressor technology. Ethylene feed was supplied to both reactors using a single compressor. Ethylene was metered into each reactor to maintain the Isopar E to ethylene ratio shown in the table below. Ethylene was combined with recycle solvent downstream of the recycle solvent flow meter and 1-octene feed injection point. 1-Octene pressure was delivered using industry standard, positive displacement pump technology. 1-Octene flow into the reactor system was metered to maintain the 1-octene to ethylene ratio shown in Table 1 below. The entire 1-octene reactor system feed was injected into the first reactor feed downstream of the recycle solvent metering system. Fresh 1-octene was not injected with the second reactor feed. Hydrogen supply pressure was delivered by a 1,500 psig gas cylinder. The hydrogen to production ratio target for each reactor was automatically manipulated by the DCS to maintain the target corresponding reactor solution viscosity. The hydrogen to product ratio target was converted to a hydrogen flow and the DCS manipulated the rising stem globe valve position to control the flow at the target value. The hydrogen to production ratio and solution viscosity targets for each reactor are recorded in the table below. Hydrogen was combined with the ethylene gas downstream of the ethylene flow controller. For the first reactor, the combined gas stream was mixed into the recycle solvent with the combined liquid stream downstream of the 1-octene injection point and for the second reactor the combined gas stream was combined with the liquid stream downstream of the recycle solvent flow controller.

[0260] The combined feed stream to each reactor was sent through a separate heat exchanger system to cool the stream to the target feed temperature shown in the table below. The flow from the heat exchanger system was directed to each reactor where it was injected into the polymerization liquid. The feed pressure was not directly controlled. The control point was the reactor pressure. Therefore, for a given total flow rate, the measured feed pressure was the result of the pressure drop in the feed system.

[0261] The pressure required to inject each catalyst component into each reactor was delivered using industry standard, positive displacement pump technology. Flow was measured using a Coriolis mass flow meter. Each component was pumped and metered separately. The catalyst complex and co-catalyst were injected into the reactor separately. Co-catalyst 2 (MMAO) was combined with co-catalyst 1 downstream of the co-catalyst 1 flow meter and the combined stream was injected into the reactor through a second syringe. As a result of this configuration, the catalyst complex for each reactor was activated in the polymerization solution.

[0262] The flow of catalyst complex to each reactor was manipulated by the DCS to control the ethylene conversion to the values shown in Table 1 below. The flow of co-catalyst 1 and co-catalyst 2 was manipulated to maintain constant molar ratios of each component to catalyst, and these values are also recorded in the table. Thus, the control of the target co-catalyst to catalyst ratio resulted in automatic adjustment of each component flow for each adjustment of the catalyst complex flow. The 1-octene conversion was not directly controlled. Rather, it resulted from the selected catalyst complex and its relative reactivity of ethylene to 1-octene for the ethylene conversion set point, and the selected reactor temperature as shown in the table. In addition to the recycle and fresh feed injected into the second reactor, there was also unreacted ethylene, 1-octene, and hydrogen in the first reactor effluent injected into the second reactor.

[0263] Solution viscosity was not directly measured. Rather, the frictional pressure loss was measured and the viscosity of the polymer solution was calculated using the Fanning equation. To calculate the viscosity, the pipe dimensions, total mass flow, density, and pressure drop across a pipe of known dimensions (inside diameter, surface roughness, and length) must be known. The mass flow and density of the reactor effluent were measured using an industry standard Coriolis mass flow meter. The pressure drop across a pipe of known dimensions was measured using an industry standard diaphragm differential pressure transmitter. The viscosity was then calculated by substituting these measurements into the Fanning equation, which is rearranged to solve for viscosity according to the following equation:

[0264]

[0265]

[0266]

[0267]

[0268] where μ = viscosity (lbsm / ft-s), dP = frictional pressure drop (psi), D = pipe inside diameter (ft), f = Fanning friction factor, p = density (lbs / ft 3 ), v = flow velocity (ft / s), L = pipe length (ft), and gc = unit conversion (lbsm-ft / lbsf-s2).

[0269] For each reactor, the hydrogen to production ratio was manipulated by the DCS and converted to a hydrogen flow target to control the solution viscosity to the target shown in Table 1.

[0270] A multimodal polyethylene composition 1 was prepared using a bis-biphenyl phenoxy catalyst as described above. The bis-biphenyl phenoxy catalyst complex having the structure described and shown above can be activated by combination with one or more co-catalysts (e.g., cation-forming co-catalysts, strong Lewis acids, or combinations). Suitable activating co-catalysts include polymeric or oligomeric aluminoxanes (especially methyl aluminoxane) and inert, compatible, non-coordinating, ion-forming compounds. Exemplary suitable co-catalysts include, but are not limited to: modified methyl aluminoxane (MMAO), bis(hydrogenated tallowalkyl)methyl tetra(pentafluorophenyl)borate (1<-1>) amine (i.e., [HNMe(C 18 H 37 )2][B(C6F5)4]) and combinations of both.

[0271] A multimodal polyethylene composition 1 was produced using two different catalyst complexes from the bis-biphenyl phenoxy family. Catalyst A was used to prepare the first reactor fraction, while catalyst B was used to prepare the second reactor fraction. Both catalysts contain hafnium metal centers (M) and have the structures shown below.

[0272]

[0273] The catalysts were activated by contacting the metal-ligand complex with bis(hydrogenated tallowalkyl)methyl tetra(pentafluorophenyl)borate (1<-1>) amine (co-catalyst 1) and MMAO (co-catalyst 2) activating co-catalysts and they have the structures shown below:

[0274]

[0275] For the first reactor, the polymerization exotherm was removed by adiabatic warming of the solvent and reactants from the feed to the reactor temperature. For the second reactor, a portion of the heat was also removed by adiabatic warming of the reactants and solvent from the feed to the reactor temperature. The remaining polymerization heat was removed non-adiabatically from the second reactor using a heat exchanger within the loop reactor. The target temperatures for each reactor are recorded in the table below.

[0276] The polymer split is defined as the weight percent of polymer produced in each reactor. When preparing the multimodal polyethylene composition 1, the polymer split was not directly controlled. Rather, the target polymer split was achieved by controlling the feed rates of the reactants and the ethylene conversion in each reactor to the targets recorded in Table 1. Along with the selected catalyst complex and its reactivity ratio of ethylene to 1-octene, these will determine the amount of polymer produced and the density of that fraction.

[0277] The ratio of 1-octene to ethylene was adjusted slightly to ensure the total polymer density was at the target noted in the table below. To decrease the polymer density, the ratio of 1-octene to ethylene was increased, which resulted in a greater flow of 1-octene to the reactor. To increase the polymer density, the ratio of 1-octene to ethylene was decreased, which resulted in a lower flow of 1-octene to the reactor.

[0278] As previously described, the polymer viscosity was controlled by manipulating the ratio of hydrogen to polymer production. To decrease the polymer viscosity, the ratio of hydrogen to polymer was increased, which resulted in a greater flow of hydrogen to the reactor. To increase the polymer viscosity, the ratio of hydrogen to polymer was decreased, which resulted in a lower flow of hydrogen to the reactor.

[0279] Water was injected into the reactor effluent to terminate the polymerization reaction. A stoichiometric amount of water relative to the total of the three catalyst components was sufficient to neutralize the catalyst and terminate activity, but a 20% or greater molar excess was used to ensure complete hydrolysis and deactivation of the catalyst.

[0280] Antioxidant was injected into the reactor effluent to protect the polymer from oxidation during the devolatilization section of the plant and during storage and subsequent processing at the converter facility. The antioxidant package for each run was mixed with solvent in a mechanically agitated vessel. An industry standard positive displacement pump was used to provide supply pressure to inject the slurry package into the reactor effluent. A Coriolis technology was used to meter the flow rate to produce the antioxidant concentration in the polymer shown in the table below.

[0281] After the reaction was terminated and the protective antioxidant package was added, a stream of steam flowed through a heat exchanger to increase the stream temperature in preparation for polymer separation. An automatically manipulated (by the DCS) rising stem globe valve located downstream of the heat exchanger was used to control the reactor system pressure full of liquid to the values shown in the table below. After passing through the reactor pressure control valve, standard solution polymerization devolatilization / separation techniques were used to separate the solvent and unreacted ethylene, 1-octene, and hydrogen from the polymer.

[0282] After the volatile components were separated from the non-volatile ethylene-1-octene copolymer in the devolatilization system, a standard Coriolis mass flow meter technique was used to measure the mass flow of the stream. A conventional gas chromatograph technique was used to measure the stream composition free of polymer. This stream information was used along with the feed stream information to calculate the conversion of ethylene and 1-octene as shown in the following equation:

[0283]

[0284]

[0285] Polymer plates were prepared for density analysis using ASTM D4703. The density of each polymer sample noted in the table below was measured using ASTM D792. Polymer melt indices and melt flow ratios (I 10 / I2) were measured using ASTM D1238. The 1st reactor and 2nd reactor density and melt index values are model estimates. The overall density, melt index, and melt flow ratio are measured values for the bimodal polymer.

[0286] Table 1. Reaction conditions for producing polyethylene composition 1

[0287]

[0288]

[0289] Polyethylene composition 1 was analyzed by iCCD. Data resulting from the iCCD test of polyethylene composition 1 is provided in Table 2, which depicts the iCCD data to include the area of the respective polyethylene fractions (25°C-35°C, 35°C-70°C, 70°C-85°C, and 85°C-120°C).

[0290] Table 2. iCCD of polyethylene composition 1 .

[0291]

[0292]

[0293] Example 2: Comparative polyethylene composition A

[0294] Comparative polyethylene composition A is a bimodal polyethylene composition that was prepared using the catalyst system and process for preparing the first composition of the invention provided in PCT Publication No. WO 2015 / 200743.

[0295] Example 3: Analysis of polyethylene composition 1 and comparative composition A

[0296] Polyethylene composition 1 of Example 1 and comparative polyethylene composition A were analyzed by iCCD. Data resulting from the iCCD test of both samples (polyethylene composition 1 of Example 1 and comparative polyethylene composition A) is provided in Table 3. Table 3 provides additional data for each sample of comparative polyethylene composition A and polyethylene composition 1, including overall density, melt index, ZSVR, and the ratio of the first fraction molecular weight to the overall molecular weight. These properties were measured based on the test methods described herein.

[0297] Table 3. Comparison of polyethylene composition 1 of Example 1 to comparative polyethylene composition A .

[0298]

[0299] Example 4: Preparation of comparative films A-F and film 1

[0300] Table 4 identifies the commercial polyethylene compositions compared to polyethylene compositions B-E.

[0301] Table 4. Comparative polyethylene compositions used in comparative films A-F

[0302]

[0303] In this example, one film comprising polyethylene composition 1 and six comparative films were prepared, each film having a total thickness of 70 μιη. Layer A of each film was 20% of the total film thickness, each layer B was 60% of the total film thickness, and each layer C was 20% of the total film thickness. The materials used to produce each film sample of Example 4 are provided in Table 5, and the extrusion conditions used to produce comparative films A-F and film 1 are summarized in Table 6.

[0304] Table 5. Layer distribution and composition of film 1 and comparative films A-F .

[0305]

[0306] Table 6. Extrusion conditions for film 1 and comparative films A-F .

[0307]

[0308]

[0309] Example 5: Analysis of comparative films A-F and film 1

[0310] To compare the performance of film 1 and comparative films A-F, the puncture force, puncture resistance, puncture elongation, puncture energy, dart impact, average Elmendorf CD tear, and average Elmendorf MD tear were measured according to the test methods described above. The puncture and dart impact results for film 1 and comparative films A-F are provided in Table 7.

[0311] Table 7. Puncture and dart impact measurements of film 1 and comparative films A-F .

[0312]

[0313] As shown in Table 7, film 1 exhibited superior puncture performance (puncture force, puncture resistance, puncture elongation, and puncture energy) than all other comparative film samples A-F. Film 1 exhibited superior puncture performance as well as dart impact (Method B) for films D and E, which used comparative polyethylene compositions having densities closest to the polyethylene composition of the present disclosure.

[0314] It will be readily apparent that modifications and variations of the present disclosure can be made in light of the above teachings. It is therefore to be understood that this invention can be practiced otherwise than as specifically set forth herein. More specifically, although particular aspects have been described herein, it is not intended to be limited to the precise forms disclosed. Rather, it is to be understood that this disclosure can include widely ranging equivalents.

Claims

1. A multi-modal polyethylene composition formed by polymerization of ethylene and C3 - C 12 olefin comonomer, the multi-modal polyethylene composition comprising: a first polyethylene fraction area of the elution profile obtained by the improved comonomer composition distribution iCCD analysis method in the temperature range of 45°C to 80°C, wherein the first polyethylene fraction area comprises from 45% to 60% of the total area of the elution profile; a second polyethylene fraction area of the elution profile obtained by the iCCD analysis method in the temperature range of 80°C to 95°C, wherein the second polyethylene fraction area comprises from 5% to 15% of the total area of the elution profile; a third polyethylene fraction area of the elution profile obtained by the iCCD analysis method in the temperature range of 95°C to 120°C, wherein the third polyethylene fraction area comprises from 25% to 50% of the total area of the elution profile; wherein the iCCD analysis method is performed using a crystallization elution fractionation instrument equipped with an IR-5 detector and a two-angle light scattering detector model 2040; wherein: the ratio of the first polyethylene fraction area to the second polyethylene fraction area is from 6 to 15; and said multimodal polyethylene composition having a density of 0.910 g / cm3 3 to 0.924 g / cm3 3 and a melt index I2 of 0.1 g / 10 min to 0.5 g / 10 min; wherein the density is measured according to ASTM D792, Method B; and wherein the melt index, I2, is measured according to ASTM D-1238 at 190°C and 2.16 kg.

2. The multimodal polyethylene composition of claim 1, wherein the multimodal polyethylene composition has a molecular weight distribution, expressed as the ratio of weight average molecular weight to number average molecular weight, Mw / Mn, in the range of 2.0 to 5.0; wherein the molecular weight distribution is calculated according to gel permeation chromatography GPC technique.

3. The multimodal polyethylene composition of claim 1, wherein the multimodal polyethylene composition has a zero shear viscosity ratio of 3 to 6; wherein the zero shear viscosity is obtained by a creep test performed on an AR-G2 stress controlled rheometer using 25 mm diameter parallel plates at 190°C.

4. The multimodal polyethylene composition of claim 2, wherein the multimodal polyethylene composition has a zero shear viscosity ratio of 3 to 6; wherein the zero shear viscosity is obtained by a creep test performed on an AR-G2 stress controlled rheometer using 25 mm diameter parallel plates at 190°C.

5. The multimodal polyethylene composition of any one of claims 1 to 4, wherein the ratio of the weight average molecular weight of the first polyethylene fraction to the weight average molecular weight of the second polyethylene fraction is from 0.75 to 1.

50.

6. The multimodal polyethylene composition of any one of claims 1 to 4, wherein the third polyethylene fraction comprises a peak, and the width of the peak at 50% peak height is from 2°C to 10°C.

7. The multimodal polyethylene composition of any one of claims 1 to 4, wherein the multimodal polyethylene composition has a tan delta ratio of 2.0 to 5.0 when measured using the DMS frequency sweep test method at 0.1 radian / second to 500 radian / second.

8. The multimodal polyethylene composition according to any one of claims 1 to 4, wherein the multimodal polyethylene composition has a tan delta of 1.0 to 6.0 when measured using the DMS frequency swap test method at 0.1 rad / s and 190°C.

9. A multimodal polyethylene composition formed by polymerization of ethylene and C3 - C 12 olefin comonomer, the multimodal polyethylene composition comprising: a first polyethylene fraction area in the temperature range of 45°C to 80°C of the elution profile obtained by the improved comonomer composition distribution iCCD analysis method, wherein the first polyethylene fraction area accounts for 45% to 60% of the total area of the elution profile; a second polyethylene fraction area in the temperature range of 80°C to 95°C of the elution profile obtained by the iCCD analysis method, wherein the second polyethylene fraction area accounts for 5% to 15% of the total area of the elution profile; a third polyethylene fraction area in the temperature range of 95°C to 120°C of the elution profile obtained by the iCCD analysis method, wherein the third polyethylene fraction area accounts for 25% to 50% of the total area of the elution profile; and wherein the multimodal polyethylene composition has a density of 0.910 g / cm3 3 to 0.924 g / cm3 3 a melt index, I2, of 0.1 g / 10 min to 0.5 g / 10 min and a molecular weight distribution, expressed as the ratio of weight average molecular weight to number average molecular weight, Mw / Mn, in the range of 2.0 to 5.0; wherein the iCCD analysis method is performed using a crystallization elution fractionation instrument equipped with an IR-5 detector and a two-angle light scattering detector model 2040; wherein the density is measured according to ASTM D792, method B; wherein the melt index I2 is measured according to ASTM D-1238 at 190°C and 2.16 kg; wherein the molecular weight distribution is calculated according to gel permeation chromatography GPC techniques.

10. A film comprising the multimodal polyethylene composition according to any one of claims 1 to 9.

11. The film according to claim 10, wherein the film is a monolayer film.

12. The film according to claim 10, wherein the film is a multilayer film.

13. The film according to claim 12, wherein one or more layers of the multilayer film comprises the multimodal polyethylene composition.

Images