High density polyethylene composition having long chain branching

Abstract

This document provides a polyethylene composition having a combination of properties including: a density ranging from about 0.930 to 0.975 g / cm 3 ; a broad molecular weight distribution (Mw / Mn ≥ 10 and / or Mz / Mn ≥ 80) and a highly branched structure (e.g., g' LCB less than or equal to 0.85, preferably less than or equal to 0.75). These polyethylene compositions may further have a low molecular weight fraction (LMWF) and a high molecular weight fraction (HMWF) such that the wt% of the LMWF in these compositions is greater than the wt% of the HMWF. These polyethylene compositions are suitable for manufacturing films, particularly oriented films such as uniaxially (longitudinally oriented) or biaxially oriented films, and particularly all-PE films.

Description

[0001] Related Applications

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 199,128, filed on December 8, 2020, entitled “High Density Polyethylene Compositions With Long Chain Branching,” which is incorporated herein by reference in its entirety. Technical Field

[0003] The present disclosure relates to polyolefin compositions, and in particular polyethylene compositions, and articles comprising or made from these compositions. Background Art

[0004] Polyolefins (such as polyethylene) with high molecular weight generally have improved mechanical properties compared to their lower molecular weight counterparts. However, high molecular weight polyolefins may be difficult to process and have high production costs. Polyolefins with lower molecular weight generally have improved processing characteristics. Polyolefins with bimodal and / or wide molecular weight distribution, with high molecular weight fraction (HMWF) and low molecular weight fraction (LMWF) may be desirable because they can combine the favorable mechanical properties of HMWF with the improved processing characteristics of LMWF.

[0005] It may be desirable to be able to produce multimodal and / or broad molecular weight distribution (MWD) polyolefins, such as multimodal high density polyethylene (HDPE) compositions, for applications including films, pressure pipes, corrugated pipes and blow molding. Ideally, the multimodal and / or broad MWD polyolefins should have excellent processing properties, as evidenced by high melt strength and high specific throughput for extrusion at low head pressures, as well as good mechanical properties.

[0006] However, even with the combination of strength and processing of bimodal HDPE, there are still challenges in incorporating such polyolefins into various applications (such as film applications) of increasing interest. One example is highly oriented films, such as biaxially oriented polyethylene (BOPE) films, which can be used to make all-PE films for greater recyclability (replacing other biaxially oriented films that are not suitable for recycling, such as biaxially oriented polypropylene, polyethylene terephthalate, and polyamide (BOPP, BOPET, and BOPA films)). However, improved polyethylene resins are needed to make BOPE films competitive with BOPP, BOPET, and BOPA films in terms of performance (e.g., stiffness, heat resistance, etc.). And while some bimodal HDPE resins can provide the strength properties required in this area, HDPE resins are generally difficult to incorporate into BOPE films because of their relatively poor orientation (oriented in the machine direction (MD) and transverse direction (TD)) and narrow acceptable operating windows (specific and limited stretch ratios, stretching temperature ranges, line speeds, etc.) required for processing.

[0007]

[0006] Therefore, there is a need for new polyolefin compositions, and in particular new polyethylene compositions, which provide suitable strength and other performance properties while still being easily processable, including in highly oriented film structures such as BOPE.

[0008] References that may be of interest in this regard include: EP 3293208 A1; EP 1330490 B1; US ​​2001 / 0014724 A1; EP 2275483 B1; US ​​6,562,905 B1; US ​​6,185,349; US 9,068,033; US 10,604,643; US 10,047,176; US Patent Publication No. 2016 / 0031191; WIPO Publication Nos. WO 2015 / 154253, WO 2017 / 127808, WO 2017 / 184633, WO 2018 / 109112, WO 2019 / 156733, WO 2020 / 001191, WO 2020 / 167498, WO 2020 / 133248; and “Biaxially oriented polyethylene films made using a combination of high density polyethylene and low density polyethylene resins,” IP.com (IPCOM000260974D), January 13, 2020; Chen, Q. et al. (2019) “Structure Evolution of Polyethylene in Sequential Biaxial Stretching along the First Tensile Direction,” Ind. Eng. Chem. Res., 58, 12419-12430. Summary of the invention

[0009] The present disclosure relates to polyolefin compositions and articles comprising these polyolefin compositions.

[0010] In some embodiments, the polyolefin composition is a high density polyethylene (HDPE) composition having a molecular weight of from about 0.930 or 0.935 to about 0.970 or 0.975 g / cm 3The polyethylene composition may have a density of 1000 g / mol, a rather broad molecular weight distribution (e.g., Mw / Mn ≥ 10 and / or Mz / Mn ≥ 80) and a highly branched structure (e.g., a g' index (LCB index) less than or equal to 0.85, preferably less than or equal to 0.75 or even 0.70, such as in the range of from 0.5 or 0.6 to 0.70, 0.75, or 0.85). The polyethylene composition may further have a melt index (MI or I) in the range of from 0.1 to 5.0 (e.g., 0.2 to 1.0). 2.16 , measured at 190° C., 2.16 kg). The polyethylene composition may also comprise 80 wt % to 99.9 wt % ethylene content and 20 wt % to 0.1 wt % C3 to C 40 α-olefin comonomer content.

[0011] Also contemplated herein are polyethylene compositions having the above-mentioned densities and further characterized by a specific relationship between their melt rheology and molecular characteristics, embodied in a "LOW ratio" as defined by the relationship below (Equation 1), so termed because it embodies the relationship between (a) low rate, low weight rheology and (b) microstructure of the polyethylene composition:

[0012]

[0013] where MI is the melt index, and g' LCB is the long chain branching index (both as defined above), η 628 is the complex viscosity at 628 rad / s (this can also be called η 低 , because at such high shear rates, the viscosity is relatively low), and Mn is the number average molecular weight. The polyethylene compositions of various embodiments may have a "low ratio" of at least 0.020 or at least 0.030, or preferably greater than 0.030, such as in the range of from 0.031 to 0.060, more preferably 0.033 to 0.050.

[0014] The polyethylene compositions of the present disclosure may additionally or alternatively be characterized by a "Broad-High Ratio" characterized across the molecular weight breadth using Mz / Mn and high load, high viscosity rheology, as defined in (Equation 2):

[0015]

[0016] The polyethylene composition according to the above and / or other embodiments may additionally or alternatively have two different fractions: a high molecular weight fraction (HMWF) and a low molecular weight fraction (LMWF). The HMWF of such embodiments may account for 40 wt% to 50 wt%; and the LMWF of such embodiments may account for 50 wt% to 60 wt%, such as from 52 wt% or 55 wt% to 60 wt% LMWF and from 40 wt% to 45 wt% or 48 wt% HMWF, such as about 55 wt% LMWF and about 45 wt% HMWF.

[0017] Still further embodiments provide articles, and particularly highly oriented articles (eg, films, such as biaxially oriented polyethylene (BOPE) films) made from the polyethylene compositions according to various embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIG. 1 a reports the small amplitude oscillatory shear (SAOS) profiles of some examples of polyethylene compositions according to the present disclosure, as well as the SAOS profiles of comparative resins CE1 and CE2.

[0019] Figure 1 b reports the SAOS profiles of the same examples of polyethylene compositions, as well as the SAOS profiles of comparative resins CE3, CE4 and CE5.

[0020] FIG. 2 a reports the gel permeation chromatography (GPC) profile of an exemplary polyethylene composition according to the present disclosure, as well as the GPC profiles of comparative resins CE1 and CE2.

[0021] FIG. 2 b reports the GPC profile of the same exemplary polyethylene composition, as well as the GPC profiles of comparative resins CE3, CE4 and CE5. DETAILED DESCRIPTION

[0022] The present disclosure relates to polyolefin compositions and articles including these polyolefin compositions. The polyolefin compositions of various embodiments are high density polyethylene (HDPE) compositions, which exhibit a unique combination of molecular structure and mechanical characteristics, which makes them particularly useful for manufacturing highly oriented applications, such as oriented films, such as MDO and BOPE films. The polyethylene composition enables excellent processing, such as by widening the acceptable operating window (temperature, line speed, etc.) of the oriented film production using the polyethylene composition. The polyethylene composition according to some embodiments may be characterized by their wide molecular weight distribution and highly branched structure. Additionally or alternatively, the features of these compositions may be low ratios (defined in the above formula 1) in the range of from 0.031 to 0.060, such as 0.033 to 0.060, preferably 0.033 to 0.045, embodying their unique rheological behavior (low viscosity at high shear rates) and a combination of long chain branched molecular structures. The increase of any one or both of these features is reflected in a higher "low ratio" (g' LCB The width-to-height ratio (defined in Equation 2 above) can be used to characterize the polyethylene composition in addition to or in lieu of the low ratio to reflect the combined Mz and g'. LCB quantification (embodying both the LCB and high molecular weight chain populations of the polyethylene composition). According to yet another aspect of the present disclosure, the polyethylene composition can be characterized additionally or alternatively by its different high molecular weight fractions and low molecular weight fractions (HMWF and LMWF). In addition, in specific embodiments, all of the above (or a subset of the above) can be used in combination to characterize the polyethylene compositions of various embodiments: For example, the polyethylene compositions of some embodiments can exhibit: (1) asymmetric bimodality. Each of these aspects is discussed in turn below (following some relevant definitions used herein).

[0023] definition

[0024] The term "polyethylene" refers to a polymer having at least 50 wt% ethylene-derived units, such as at least 70 wt% ethylene-derived units, such as at least 80 wt% ethylene-derived units, such as at least 90 wt% ethylene-derived units, or at least 95 wt% ethylene-derived units, or 100 wt% ethylene-derived units. Thus, the polyethylene can be a homopolymer or a copolymer having one or more other monomeric units, including a terpolymer. The polyethylene described herein can, for example, include at least one or more other olefins and / or comonomers.

[0025] "Olefins", alternatively referred to as "alkenes", are linear, branched, or cyclic compounds of carbon and hydrogen with at least one double bond. For the purposes of this specification and the appended claims, when a polymer or copolymer is referred to as comprising an olefin, the olefin present in such a polymer or copolymer is the polymerized form of the olefin. For example, when a copolymer is said to have an "ethylene" content of 50 wt% to 55 wt%, based on the weight of the copolymer, it is understood that the monomer units in the copolymer are derived from ethylene in the polymerization reaction, and the derived units are present at 50 wt% to 55 wt%. A "polymer" has two or more identical or different monomer units. A "homopolymer" is a polymer having identical monomer units. A "copolymer" is a polymer having two or more monomer units that are different from each other. A "terpolymer" is a polymer having three monomer units that are different from each other. Therefore, as used herein, the definition of copolymer includes terpolymers, etc. "Different" as used to refer to monomer units indicates that the monomer units differ from each other by at least one atom or are isomerically different.

[0026] The term "alpha-olefin" refers to an olefin having a terminal carbon-carbon double bond in its structure. 1 R 2 C=CH2, where R 1 and R 2 can be independently hydrogen or any hydrocarbon group; such as R 1 is hydrogen, and R 2 A "linear alpha-olefin" is one in which R 1 is hydrogen and R 2 It is hydrogen or a linear alkyl alpha-olefin.

[0027] For purposes of this disclosure, ethylene shall be considered an alpha-olefin.

[0028] When a polymer or copolymer is referred to herein as containing alpha-olefins (alpha-olefin or α-olefin) (including but not limited to ethylene, 1-butene and 1-hexene), the olefin present in such polymer or copolymer is the polymerized form of the olefin. For example, based on the weight of the ethylene content plus the comonomer content, when a polymer is said to have an "ethylene content" or "ethylene monomer content" of 80 wt% to 99.9 wt% or contain 80 wt% to 99.9 wt% "ethylene-derived units", it is understood that the monomer units in the copolymer are derived from ethylene in the polymerization reaction, and the derived units are present at 80 wt% to 99.9 wt%.

[0029] As used herein and unless otherwise indicated, the term “ n ” means a hydrocarbon having n carbon atoms per molecule, where n is a positive integer.

[0030] Polyethylene composition

[0031] The polyethylene composition of the present disclosure may include C2 to C 40 Olefins with one, two, three or more different C2 to C 40 In a particular embodiment, the polyethylene composition comprises a majority of units derived from polyethylene, and units derived from one or more C3 to C 40 Comonomers, preferably C3 to C 20 α-olefin comonomer (e.g., propylene, 1-butene, 1-hexene, 1-octene, 1-decene, 1-dodecene, preferably propylene, 1-butene, 1-hexene, 1-octene, or a mixture thereof; more preferably 1-butene and / or 1-hexene, and in some cases, most preferably 1-butene).

[0032] The polyethylene composition can contain at least 80 wt%, or 85 wt%, preferably at least 90 wt%, 95 wt%, 96 wt%, 97 wt%, 98 wt%, 98.5 wt% or 99 wt% (e.g., at a low end of 80 wt%, 85 wt%, 90 wt%, 95 wt%, 98 wt%, 98.5 wt%, 98.7 wt%, 99.0 wt%, 99.1 wt%, 99.2 wt%, 99.3 wt%, or 99.4 wt% to 96 wt%, 97 wt%, 98.1 wt%, 98 wt%, 98.5 wt%, 98.7 wt%, 99.0 wt%, 99.1 wt%, 99.2 wt%, 99.3 wt%, or 99.4 wt%). %, 98.2 wt%, 98.3 wt%, 98.4 wt%, 98.5 wt%, 98.6 wt%, 98.7 wt%, 98.8 wt%, 98.9 wt%, 99.0 wt%, 99.1 wt%, 99.2 wt%, 99.3 wt%, 99.4 wt%, 99.5 wt%, 99.6 wt%, 99.7 wt%, 99.8 wt%, or 99.9 wt% in the range of the upper values, wherein ranges from any of the foregoing lower values ​​to any of the foregoing higher values ​​are contemplated with the proviso that the higher value is greater than the lower value). For example, the polyethylene composition may contain 95 wt%, 98 wt%, 98.5 wt%, 98.7 wt%, or 99 wt% to 99.4 wt%, 99.5 wt%, or 99.6 wt% ethylene derived units. %, 1.4 wt%, 1.5 wt%, 1.6 wt%, 1.7 wt%, 1.8 wt%, 1.9 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 10 wt%, 15 wt%, or 20 wt% (wherein ranges from any of the foregoing lower values ​​to any of the foregoing higher values ​​are contemplated with the proviso that the higher value is greater than the lower value) of comonomer units (e.g., C2 to C4). 20 α-olefin derived units, such as units derived from butene, hexene and / or octane). For example, the polyethylene composition may contain from 0.4 wt% or 0.5 wt% to 1.0 wt%, 1.3 wt%, 1.5 wt%, 2.0 wt%, or 5.0 wt% comonomer units.

[0033] Although several suitable comonomers have been indicated in various examples, other α-olefin comonomers are contemplated. For example, the α-olefin comonomers may be linear or branched, and two or more comonomers may be used if desired. Examples of suitable comonomers include linear C3-C 20 α-olefins (butene, hexene, octane as already indicated), and α-olefins with one or more C1-C3 alkyl branches or aromatic groups. Specific examples include propylene; 3-methyl-1-butene; 3,3-dimethyl-1-butene; 1-pentene; 1-pentene with one or more methyl, ethyl or propyl substituents; 1-hexene with one or more methyl, ethyl or propyl substituents; 1-heptene with one or more methyl, ethyl or propyl substituents; 1-octene with one or more methyl, ethyl or propyl substituents; 1-nonene with one or more methyl, ethyl or propyl substituents; 1-decene substituted with ethyl, methyl or dimethyl; 1-dodecene; and styrene. It should be understood that the above list of comonomers is merely exemplary and not intended to be limiting. In some embodiments, comonomers include propylene, 1-butene, 1-pentene, 4-methyl-l-pentene, 1-hexene, 1-octene and styrene.

[0034] The polyethylene composition according to various embodiments may have a molecular weight of 0.930 to 0.975 g / cm 3 , such as 0.938 to 0.965 g / cm 3 For example, the ethylene polymer may have a density of from 0.935, 0.940, 0.945, 0.950, 0.953, 0.955, 0.956, or 0.957 g / cm 3 The lower end value is 0.960, 0.961, 0.962, 0.963, 0.964, 0.965, 0.966, 0.970 or 0.975 g / cm 3 The density of the high end value is 0.953 to 0.965 g / cm2, wherein the range of various embodiments includes any combination of any upper or lower limits disclosed herein (wherein 0.953 to 0.965 g / cm2 is of particular interest in some embodiments) 3 , such as 0.955 to 0.963 g / cm 3 Density of ). Density herein is measured on a plaque using a density gradient column according to ASTM D1505-19 (gradient density). The plaque is molded according to ASTM D4703-10a, Procedure C, and the plaque is conditioned at 23° C. for at least 40 hours according to ASTM D618-08 to achieve equilibrium crystallinity.

[0035] Polyethylene composition - microstructure (molecular characteristics)

[0036] In various embodiments, the polyethylene composition has one or more, two or more, or preferably all of the following molecular weight characteristics:

[0037] The weight average molecular weight (Mw) is generally in the range of from 100,000 to 250,000 g / mol; and specifically in the range of from any of the low end values ​​of 100,000, 110,000, 120,000, or 130,000 g / mol to any of the high end values ​​of 170,000, 175,000, 180,000, 190,000, 200,000, 225,000, or 250,000 g / mol, wherein ranges from any of the foregoing lower end values ​​to any of the foregoing higher end values ​​are contemplated (e.g., 120,000 or 130,000 g / mol to 180,000 or 200,000 g / mol).

[0038] The number average molecular weight (Mn) is typically in the range of from 5,000 to 30,000, such as from a low end of any of 5,000, 6,000, 7,000, 8,000, or 9,000 g / mol to a high end of any of 11,000, 12,000, 13,000, 14,000, 15,000, 20,000, 25,000, or 30,000 g / mol, wherein ranges from any of the foregoing lower values ​​to any of the foregoing higher values ​​are contemplated (e.g., 8,000 or 9,000 g / mol to 11,000 or 15,000 g / mol).

[0039] The Z-average molecular weight (Mz) is typically in the range of from 700,000 to 2,000,000 g / mol; and specifically in the range of from the low end of any of 700,000, 750,000, 800,000, 850,000, and 900,000 g / mol to the high end of any of 1.2 M, 1.3 M, 1.4 M, 1.5 M, 1.6 M, 1.7 M, 1.8 M, 1.9 M, or 2.0 M g / mol, wherein ranges from any of the foregoing low end values ​​to any of the foregoing high end values ​​are contemplated (e.g., 700,000 g / mol to 1.5 M g / mol, such as 800,000 g / mol to 1.2 M g / mol). In certain embodiments, the Mz can be at least 700,000 g / mol, such as 800,000 g / mol or greater, 850,000 g / mol or greater, or 900,000 g / mol or greater, with no upper limit necessarily contemplated or required.

[0040] The polyethylene compositions according to various embodiments of the present invention preferably include a high molecular weight fraction and a low molecular weight fraction, and can exhibit a multimodal (e.g., bimodal) distribution in a GPC analysis of the molecular weight distribution, which means that there are multiple (e.g., 2, 3 or more; preferably 2) distinguishable peaks in the molecular weight distribution curve of the composition (as determined using gel permeation chromatography (GPC) or other recognized analytical techniques, noting that if there is any conflict between analytical techniques, the molecular weight distribution determined by GPC as described below shall prevail). Examples of "unimodal" molecular weight distributions can be found in U.S. Pat. No. 8,691,715, Figure 6 of the patent, which is incorporated herein by reference. This is in contrast to a "multimodal" molecular weight distribution (again, as determined by GPC or any other recognized analytical technique, if there is any conflict, GPC shall prevail). For example, if there are two distinguishable peaks in the molecular weight distribution curve, such a composition can be referred to as a bimodal composition. For example, in the '715 patent, Figures 1-5 of the patent show representative bimodal molecular weight distribution curves. In these figures, there are valleys between the peaks, and the peaks can be separated or deconvoluted.

[0041] Taking into account such peak morphology, the polyethylene compositions of various embodiments may exhibit a Mw / Mn ratio (sometimes referred to as a polydispersity index (PDI), or a quantification of the molecular weight distribution (MWD)) in the range of 10 or greater, preferably 12 or greater, such as from 10, 11, or 12 to 15, 16, 17, 20, 22, or 25, with ranges from any of the foregoing lower values ​​to any of the foregoing higher values ​​also contemplated (e.g., 11 to 20 or 12 to 17). The Mz / Mn ratio (indicating the breadth of the overall distribution of molecular weights between chains within a polymer by considering two characteristic values ​​of very high molecular weight chains (Mz) and very low molecular weight chains (Mn)) is at least 70, such as 75 or greater, or more preferably 85 or greater. In certain embodiments, the Mz / Mn can range from a low of any of 70, 75, 80, 81, 82, 83, 84, or 85 to a high of any of 100, 105, 110, 115, 120, 125, or 130, with ranges from any low to any high being contemplated (e.g., 75 to 110, or 80 to 100). Additionally, the polyethylene composition can have an Mz / Mw in the range of from 4, 5, or 6 to 8, 9, 10, 12, or 15 (with ranges from any low to any high being contemplated).

[0042] The polyethylene compositions according to various embodiments also exhibit a significant degree of long chain branching and thus may have a g' value (also referred to as g'vis, g' LCB, branching index, or long chain branching (LCB) index). For example, g' LCB It can range from a low end value of any of 0.50, 0.55, 0.60 or 0.65 to a high end value of 0.69, 0.70, 0.71, 0.73, 0.75, 0.80, or 0.85 (wherein ranges from any of the foregoing low end values ​​to any of the foregoing high end values, such as 0.50 to 0.80 or 0.55 to 0.75 are contemplated).

[0043] The distribution and moment of molecular weight (Mw, Mn, Mz, Mw / Mn, Mz / Mn, etc.), monomer / comonomer content (C2, C4, C6 and / or C8, and / or other, etc.) and long chain branching index (g') were determined by using a high temperature gel permeation chromatography (PolymerChar GPC-IR) equipped with an infrared detector IR5 based on a multi-channel bandpass filter, an 18-angle light scattering detector and a viscometer. Three Agilent PLgel 10 μm Mixed-B LS columns were used to provide polymer separation.

[0044] The detailed analytical principles and methods for molecular weight determination are described in paragraphs

[0044] -

[0051] of PCT Publication WO 2019 / 246069A1, which is incorporated herein by reference (note that the formula c= / / / mentioned in paragraph

[0044] for the concentration (c) at each point in the chromatogram is c=βI, where β is the mass constant and I is the IR5 broadband signal intensity (I) minus the baseline). Unless otherwise noted, all molecular weight moments used or referred to in this disclosure are determined according to conventional molecular weight (IR molecular weight) determination methods (e.g., as referred to in paragraphs

[0044] -

[0045] of the just-noted publication), noting that for the formula in this paragraph

[0044] , a=0.695 and K=0.000579 (1-0.75 Wt) are used, where Wt is the weight fraction of the hexane comonomer, and further noting that the comonomer composition is determined by the ratio of the IR5 detector intensities corresponding to the CH2 and CH3 channels calibrated with a series of PE and PP homopolymer / copolymer standards, the nominal values ​​of which are predetermined by NMR or FTIR (providing the number of methyl groups per 1000 total carbons (CH3 / 1000TC)), as noted in paragraph

[0045] of the just-noted PCT publication).

[0045] On the other hand, the branching index g' is determined using light scattering (LS) according to the method described in paragraphs

[0048] -

[0051] of PCT publication WO 2019 / 246069 A1 LCB (also known as g' vis), the following clarification is made: When the optical constant K is determined according to paragraph

[0048] of the reference o When, for any ethylene copolymer other than ethylene-butene, ethylene-hexene, and ethylene-octene copolymers, dn / dc=0.1048 ml / mg and A2=0.0015; in addition, M v (used to determine g' according to paragraph

[0051] of WO'069 disclosure LCB ) is the viscosity average molecular weight determined by LS analysis; and finally, also in g' LCB In the determination, K = 0.0005 and α = 0.695 for all ethylene copolymers except for ethylene-butene, ethylene-hexene, and ethylene-octene copolymers specifically noted in the WO '069 disclosure. It is also noted that Mn is sensitive to the low molecular weight tail affected by smaller molecules such as oligomers. On the other hand, the sensitivity of Mw and Mz is significantly lower. However, for all samples, the GPC range is selected between 2.6-2.7 LogMW (g / mol) (low molecular weight limit) and 6.9-7.0 LogMW (high molecular weight limit).

[0046] Rheological properties

[0047] In various embodiments, the polyethylene composition has a melt index (MI, also referred to as I2 or I3) in the range of from 0.1 g / 10 min to 5 g / 10 min, such as from a low end of any one of 0.1, 0.3, 0.5, and 0.6 g / 10 min to a high end of any one of 0.85, 0.90, 0.95, 1.0, 1.5, 2.0, 3.0, 4.0, or 5.0 g / 10 min. 2.16 , recognizing that a 2.16 kg load is used in the test) (ranges from any of the foregoing lower values ​​to any of the foregoing higher values ​​are contemplated herein) (e.g., 0.1 to 1.0 g / 10 min, such as 0.6 to 0.9 g / 10 min). In addition, the polyethylene compositions of various embodiments can have a high load melt index (HLMI) (also referred to as I ) ranging from a low end value of 25, 30, 35, 40, 45, 46, 47, 48, 49, or 50 g / 10 min to a high end value of any of 60, 65, 70, 75, 80, 85, or 90 g / 10 min. 21 or I 21.6 , recognizing that a 21.6 kg load was used in the test), wherein ranges from any of the foregoing lower end values ​​to any of the foregoing higher end values ​​(e.g., 40 to 80 g / 10 min, such as 45 to 65 g / 10 min) are contemplated herein.

[0048] The polyethylene composition according to various embodiments can have a melt index ratio (MIR, defined as I IR) ranging from a low end value of any of 30, 35, 40, 45, 50, 55, 60, 65, 66, 67, 68, 69, or 70 to a high end value of any of 80, 81, 82, 83, 84, 85, 90, 95, 100, 110, 120, 130, 140, or 150. 21.6 / I 2.16 or HLMI / MI), wherein ranges from any of the foregoing lower values ​​to any of the foregoing higher values ​​(e.g., 30 to 140, 50 to 100, 65 to 90, 70 to 85, etc.) are contemplated herein.

[0049] Melt index (2.16 kg) and high load melt index (HLMI, 21.6 kg) values ​​can be determined according to ASTM D1238-13 Procedure B, such as by using a Gottfert MI-2 series melt flow indexer. For the MI, HLMI and MIR values ​​reported herein, the test conditions were set at 190°C and 2.16 kg (MI) and 21.6 kg (HMLI) loads.

[0050] In various embodiments, the polyethylene composition exhibits shear-thinning rheology, which means that as the shear rate increases, the viscosity decreases. This rheology indicates good processing properties of the polyethylene composition according to such embodiments (as long as the shear rate simulates the viscosity that the composition may exhibit when processed in an extruder or similar equipment). Therefore, the polyethylene composition according to various embodiments may exhibit one or more, preferably two or more, or even all of the following rheological properties:

[0051] The shear thinning degree DST ranges from a low end value of 0.920, 0.925, 0.930, 0.935, or 0.940 to a high end value of 0.950, 0.955, 0.960, 0.965, 0.970, 0.980, 0.985, or 0.990, wherein ranges from any of the foregoing low end values ​​to any of the foregoing high end values ​​(e.g., 0.920 to 0.970, such as 0.940 to 0.960) are contemplated herein. DST is a measure of shear thinning rheological behavior (viscosity decreases with increasing shear rate) and is defined as DST = [η*(0.01 rad / s) - η*(100 rad / s)] / η*(0.01 rad / s), where η*(0.01 rad / s) and η*(100 rad / s) are the complex viscosities at 0.01 rad / s and 100 rad / s, respectively.

[0052] · Complex viscosity (at 628 rad / s, 190°C) is 800, 700, 600, 500, 450, or 400 Pa*s or less; such as in the range of from a low end value of 200, 250, 300, 325, or 350 Pa*s to a high end value of 400, 450, 500, 550, 600, 650, 700, 750, or 800 Pa*s, wherein in various embodiments a range from any of the foregoing low end values ​​to any of the foregoing high end values ​​(provided that the high end value is greater than the low end value) is contemplated. (e.g., 200 to 400 Pa*s, such as 300 to 400 Pa*s).

[0053] · Complex viscosity (at 100 rad / s, 190°C) is 3,000 Pa*s or less, such as 2,000 Pa*s or less; such as within a range from a low end value of any of 700, 800, 900, 1000, or 1,100 Pa*s to a high end value of any of 1,200, 1,300, 1,400, 1,500, 1,600, 1,700, 1,800, 1,900, or 2,000 Pa*s, wherein ranges from any of the foregoing low end values ​​to any of the foregoing high end values ​​are contemplated (e.g., 700 to 2,000 Pa*s, such as 1,000 to 1,300 Pa*s).

[0054] The complex viscosity (at 0.01 rad / s, 190° C.) is 50,000 Pa*s or less, such as 40,000 Pa*s or less, or 35,000 Pa*s or less; or in some cases within a range from a low end value of 10,000, 15,000, 20,000, or 25,000 Pa*s to a high end value of 30,000, 35,000, 40,000, 45,000, or 50,000 Pa*s, wherein ranges from any low end value to any high end value are contemplated herein (e.g., 10,000 to 50,000 Pa*s, such as 15,000 to 40,000 Pa*s, or 20,000 to 35,000 Pa*s).

[0055] Rheological data (such as complex viscosity) are determined using SAOS (small amplitude oscillatory shear) testing. SAOS experiments are performed at 190°C using 25 mm parallel plates configured on an ARES-G2 (TA Instruments). Sample test discs (25 mm in diameter, 2 mm in thickness) are made at 190°C using a Carver laboratory press. The samples are allowed to stand for approximately 3 minutes without pressure in order to melt, and then typically held for 3 minutes under pressure to compression mold the samples. The disc-shaped samples are first balanced between the parallel plates of the rheometer at 190°C for approximately 5 minutes to eliminate any previous thermal and crystallization history. Next, an angular frequency sweep was performed using a typical measurement gap of 1.5 mm, from 628 rad / s to 0.01 rad / s angular frequency, using 5 points / order of magnitude, and strain values ​​in the linear viscoelastic region determined by strain sweep experiments (see CW Macosko, Rheology Principles, Measurements and Applications, Wiley-VCH Press, New York, 1994). All experiments were performed in a nitrogen atmosphere to minimize any degradation of the sample during rheological testing.

[0056] In addition, the polyethylene composition may additionally or alternatively have a tan (δ) value indicative of medium long chain branching (LCB); and particularly a tan (δ) in the range of from a low value of 1.5, 2, 3, 3.5, or 4.0 to a high value of 4.5, 5.0, 5.5, 6.0, or 6.5 (wherein a range from any low value to any high value is contemplated). As used herein, tan (δ) is measured using dynamic shear rheometry, wherein discrete data points are taken at a frequency of 0.01585 rad / s, and the test conditions are: temperature 190° C., and stress amplitude 200 Pa.

[0057] Microstructure and rheology relationship

[0058] As previously noted, polyethylene compositions according to various embodiments may exhibit one or more of the above-mentioned properties, and in particular one or more of the microstructural properties and one or more of the rheological properties. In addition, the characteristics of such polyethylene compositions may be a combination of microstructure and rheology by any of a variety of means.

[0059] For example, the polyethylene compositions of various embodiments exhibit a "low ratio" as defined by the following relationship in (Equation 1), so stated because it embodies the relationship between (1) the low speed, low weight rheology and (2) the microstructure of the polyethylene composition:

[0060]

[0061] Where MI is the melt index (I at 190°C) 2.16 , in g / 10min) and g' LCB is the long-chain branching index (unitless), η 628 is the complex viscosity in Pa*s at 628 rad / s (this can also be called η 低 , because the polyethylene composition shows relatively low viscosity under such high shear rate), and Mn is the number average molecular weight in g / mol. As defined ratio should be considered to be similar to an index, and therefore unitless for the purpose of present disclosure. The " low ratio " that the polyethylene composition of various embodiments has can be at least 0.02 or at least 0.03, preferably greater than 0.030, such as from any low end value in 0.031, 0.032 or 0.033 to any high end value in 0.050, 0.10, 0.20, 0.30, 0.40, 0.50 or 0.60, wherein also contemplates the scope from any aforementioned low end value to any aforementioned high end value (for example, from 0.030, 0.031 or 0.032 low end value to 0.050 or 0.50 or 0.60 high end value in the range).

[0062] Additionally or alternatively, by using Mz / Mn and high load, high viscosity rheological profiles, the concept can be extended to reflect profiles across the entire molecular weight breadth by defining the "width-height ratio" as follows:

[0063]

[0064] Wherein Mz and Mn are z-average molecular weight and number average molecular weight (g / mol); HLMI is high load melt index (I 21.6 , at 190°C); η 0.01 is the complex viscosity at 0.01 rad / s (in Pa*s); and g' LCB It is LCB index (unitless). Like " low ratio ", final value is considered to be similar to index, and therefore is unitless for the purpose of present disclosure.The polyethylene composition of various embodiments can have such " width-height ratio ", and it is at least 0.15, preferably at least 0.20, as in the range of any high end value from any low end value in 0.15, 0.20 or 0.21 to 0.40, 0.45, 0.50, 0.60, 0.70, 1.0, 2.0, 3.0, 4.0, 5.0, 5.5 or 6.0 (wherein envisioning the scope from any aforementioned low end value to any aforementioned high end value, such as 0.20 to 0.70, 1.0, 2.0, 3.0 or 6.0).This can be used as the low ratio value previously indicated to substitute or preferably as the supplement of the low ratio value previously indicated.

[0065] Polyethylene composition fractions

[0066] The polyethylene composition according to any of the various embodiments herein may have a low molecular weight fraction LMWF and a high molecular weight fraction HMWF. For example, the polyethylene composition may contain from 0.1 wt% to 99.9 wt% LMWF, the balance being made up of HMWF (wherein wt% is based on the total polymer, such that LMWF+HMWF=100%). For example, the polyethylene composition may contain from 30 wt% to 70 wt% LMWF, such as from 40 wt% to 60 wt% LMWF, or 40 wt% to 50 wt% or even 45 wt% to 55 wt% LMWF (wherein HMWF forms the balance in each case).

[0067] In some preferred embodiments, the polyethylene composition may include more LMWF than HMWF. For example, the amount of HMWF that the polyethylene composition may include is in the range of from about 40wt%, 41wt%, 42wt% or 43wt% low end value to 47wt%, 48wt%, 49wt%, or 49.9wt% high end value (wherein the scope from any of the aforementioned low end value to any of the aforementioned high end value is contemplated herein), and the balance is LMWF. For example, some embodiments may include 40wt%-49.9wt%, 41wt%-49wt%, or 42wt%-47wt% HMWF, and correspondingly 50.1wt%-60wt%, 51wt%-59wt%, or 53wt%-58wt% LMWF.

[0068] As discussed below, many embodiments include polyethylene compositions prepared in multiple (according to some embodiments 2 or more, preferably 2) series polymerization reaction zones. In particular, in these embodiments, LMWF is prepared in a first series reaction zone, and then LMWF is introduced into a second series reaction zone downstream of the first series reaction zone to produce a polyethylene composition (including HMWF formed in the second reaction zone and existing (e.g., remaining unreacted) LMWF). For such embodiments, the characteristics of LMWF can be directly determined (e.g., by sampling some parts of the polymer product taken from the first reactor, and / or separating from the final product). One or more characteristics of the polyethylene composition can also be directly determined.

[0069] Alternatively, in embodiments where the LMWF and HMWF are produced in parallel reactors and then post-reactor blended, the properties of both the LMWF and HMWF (and the final post-blending polymer composition) can be determined directly.

[0070] In certain embodiments, the LMWF may be an ethylene homopolymer (e.g., the LMWF may be obtained by polymerizing ethylene in a first reaction zone without adding a comonomer), and the HMWF may be a copolymer, such as an ethylene-butene or ethylene-hexene copolymer. In such embodiments, the HMWF may be a polymerization product obtained by feeding a comonomer with ethylene and / or a LMWF product (in a tandem reaction embodiment) at a comonomer / ethylene ratio (based on moles of comonomer / moles of ethylene, such that 2.5% means 2.5 moles of comonomer per 100 moles of ethylene) in a range from 0.25% or 0.5% to 2.0% or 2.5%.

[0071] Thus, in some embodiments, the HMWF of the polyethylene composition has a lower density than the LMWF of the polyethylene composition. In other words, the LMWF of the polyethylene composition can have a higher density than the HMWF of the polyethylene composition.

[0072] Method for preparing polyethylene composition

[0073] In some embodiments, a single site catalyst may be fed into a staged reactor. Ethylene and optional α-olefin comonomers (e.g., C3-C 10 The density of the polyethylene composition can be adjusted by adding a plurality of α-olefins (such as 1-butene) to the polyethylene composition. The polyethylene composition can be produced using a gas phase reactor, a slurry loop reactor, a solution process or a CSTR in series or any combination thereof. HMWF can be produced in the first reactor or the second reactor. Similarly, LMWF can be produced in the first reactor or the second reactor, wherein LMWF is produced in a reactor different from HMWF. Any suitable Ziegler-Natta catalyst can be used to produce LMWF and / or HMWF. In some specific embodiments, LMWF is produced in the first series reactor, and HMWF is produced in the second series reactor downstream of the first series reactor.

[0074] As a more specific example, in some embodiments, LMWF is formed in the first reactor (in a series of reactors). LMWF, catalyst, unreacted monomer, diluent and hydrogen are fed to a flash tank from the outlet of the first reactor, and hydrogen and unreacted monomer are removed in the flash tank. The LMWF particles containing the active catalyst are fed to the second series reactor from the flash tank. Monomer and hydrogen (optional comonomer) and solvent are added to the second reactor. In some embodiments, it is not necessary to feed new catalyst into the second reactor.

[0075] In general, any suitable polymerization method can be used to obtain the polyethylene composition according to various embodiments. For example, U.S. Pat. Nos. 10,604,643 and 10,047,176 describe a series of cascaded slurry loop polymerization reactors for producing bimodal HDPE; such methods are generally suitable for producing the polyethylene composition of the present disclosure, however, it is noted that according to embodiments of the present disclosure, particularly high pressures (e.g., 8-9 bar) in the first series reactor are used to produce LMWF. It may be preferred. In addition, in the context of such series slurry loop polymerization, hydrogen can be used in the two series reactors, for example, to control the molecular weight. According to specific embodiments of the present invention, the first reactor (in a specific embodiment, a LMWF reactor) can be provided with hydrogen so that the ratio of hydrogen to ethylene as measured in the reactor is in the range of from 2 to 7 mol hydrogen / mol ethylene (e.g., 2 to 5 mol H2 / mol ethylene, or 3 to 4 mol H2 / mol ethylene). The second reactor (in a particular embodiment, a HMWF reactor) can be provided with hydrogen such that the ratio of hydrogen to ethylene as measured in the reactor is in the range of from 0.05 to 1 mol hydrogen / mol ethylene (e.g., 0.1 to 0.5 mol H2 / mol ethylene, or 0.1 to 0.3 mol H2 / mol ethylene). In addition, according to certain embodiments, it is preferred to use 2 reactors in series (not 3 or more). Finally, the branching content is preferably controlled at least in part by post-reactor modification of the polyethylene particles recovered from the polymerization reaction, such as post-reactor air and / or oxygen injection (e.g., air is injected into a mixer with solid polyethylene product at a flow rate such that about 0.1 to 0.5 lb of air is injected per lb of solid polyethylene product).

[0076] Other potentially suitable tandem reaction processes are described, for example, in U.S. Pat. No. 6,185,349, where polymerization is described as a slurry loop polymerization in series followed by a gas phase polymerization reaction, although it is noted in this regard that US 6,185,349 describes a significantly lower H2 feed to the LMWF (1st series) reactor than the embodiments contemplated herein (e.g., 200-800 mol H2 / 1000 mol ethylene, or a molar ratio of 0.2 to 0.8).

[0077] Generally, unless otherwise specifically noted, a first "reactor" and a second "reactor" referred to herein may equally mean a "reaction zone" (e.g., a discrete portion within a reactor vessel), such that a single reactor vessel may include multiple reactor zones. Similarly, a "reactor" or reaction zone may in principle include multiple reactor vessels in parallel (e.g., such that instead of the "first reactor" being a single vessel, it may equally include two, three or more parallel reactors into which polymerization feed components are diverted, and polymerization is conducted under the same conditions). The products (including LMWF) may be combined together and fed to a second series reactor or reaction zone (which itself may include multiple parallel reactor vessels operating under substantially similar conditions); alternatively, the products may be maintained in parallel and fed to respective second reactor vessels operating under substantially the same conditions, with the final products from the multiple second reactor vessels being combined.

[0078] After the polymerization process, suitable post-treatment processes as known can be used. For example, in a slurry process, the resulting slurry is separated from the diluent and dried. From this, the polymer is sent to a post-treatment section. When the particles are post-treated into a final granular form, antioxidants and neutralizing additives can be added to the product.

[0079] Alternatively, the LMWF and HMWF are formed in parallel reactors or reaction zones followed by post-reactor blending of the LMWF and HMWF in any suitable post-reactor blending process. Preferably, however, the LMWF and HMWF are formed in series reactors as described above.

[0080] The polymerization may be carried out using a catalyst system comprising a Ziegler-Natta catalyst, a cocatalyst and optionally a support material.

[0081] Ziegler-Natta catalyst

[0082] The catalyst may include, for example, any Ziegler-Natta (ZN) transition metal catalyst, such as Ziegler Catalysts 363-386 (G. Fink, R. Mulhaupt and HH Braintzinger, eds., Springer-Verlag 1995); or those disclosed in EP 103120; EP 102 503; EP 0 231 102; EP 0 703 246; RE 33,683; U.S. Pat. Nos. 4,302,565; 5,518,973; 5,525,678; 5,288,933; 5,290,745; 5,093,415 and 6,562,905. Other examples of ZN catalysts are discussed in U.S. Pat. Nos. 4,115,639, 4,077,904, 4,482,687, 4,564,605, 4,721,763, 4,879,359, and 4,960,741. Typically, the ZN catalyst comprises a transition metal compound from Groups 3 to 17, or Groups 4 to 12, or Groups 4 to 6 of the Periodic Table of the Elements. As used herein, reference to the Periodic Table of the Elements and its Groups is to the NEW NOTATION as published in Hawley's Condensed Chemical Dictionary, Thirteenth Edition, John Wiley & Sons, Inc., (1997), unless reference is made to the previous IUPAC form (also presented in the same form) represented by Roman numerals, or unless otherwise indicated. Examples of such catalysts include those comprising Group 4, 5 or 6 transition metal oxides, alkoxides and halides, or oxides, alkoxides and halide compounds of titanium, zirconium or vanadium; optionally in combination with a magnesium compound, internal and / or external electron donors (alcohols, ethers, siloxanes, etc.), alkylaluminum or alkylboron and alkyl halides, and an inorganic oxide support.

[0083] The ZN catalyst can be represented by the formula: MRx, wherein M is a metal from Groups 3 to 17, such as Groups 4 to 6, such as Group 4, such as titanium; R is a halogen or a hydrocarbyl group; and x is the valence of the metal M. Non-limiting examples of R include alkoxy, phenoxy, bromo, chloro, and fluoro.

[0084] In one class of embodiments, the ZN catalyst may include at least one catalyst having the formula Ti(OR) a X b A titanium compound wherein R is a substituted or unsubstituted hydrocarbon group, such as C1 to C 25 an aliphatic or aromatic group; X is selected from Cl, Br, I, and combinations thereof; a is selected from 0, 1, and 2; b is selected from 1, 2, 3, and 4; and a+b=3 or 4. As used herein, "hydrocarbyl" refers to a moiety comprising hydrogen and carbon atoms.

[0085] Non-limiting examples where M is titanium include TiCl3, TiCl4, TiBr4, Ti(OCH3)Cl3, Ti(OC2H5)3Cl, Ti(C2H5)Cl3, Ti(OC4H9)3Cl, Ti(OC3H7)2Cl2, Ti(OC2H5)2Br2, Ti(OC6H5)Cl2, Ti(OCOCH3)Cl3, Ti(OCOC6H5)Cl3, TiCl3 / 3AlCl3, Ti(OC 12 H 25 )Cl3 and combinations thereof.

[0086] In one class of embodiments, the ZN catalyst may include at least one magnesium compound. The at least one magnesium compound may have the formula MgX2, wherein X is selected from the group consisting of Cl, Br, I, and combinations thereof. The at least one magnesium compound may be selected from: MgCl2, MgBr2, and MgI2. ZN catalysts based on magnesium / titanium electron-donor complexes are described, for example, in U.S. Pat. Nos. 4,302,565 and 4,302,566. ZN catalysts derived from Mg / Ti / Cl / THF are also contemplated.

[0087] In at least one embodiment, the ZN catalyst is titanium chloride on a magnesium chloride support. In addition, according to known polymerization catalysis techniques, a cocatalyst (also known as an activator or modifier, such as an alkyl aluminum compound) can be used together with the ZN catalyst to form a catalyst system. The catalyst system can also be further loaded according to known techniques. Commercial supports include ES70 and ES757 silica families obtained from PQ Corporation, Malvern, Pa. Other commercial supports include Sylopol TM Silica supports, including 955 silica and 2408 silica, are available from Grace Catalyst Technologies, Columbia, Md.

[0088] Still other suitable ZN catalysts and cocatalysts for use therewith are disclosed in U.S. Pat. Nos. 4,124,532, 4,302,565, 4,302,566, 4,376,062, 4,379,758, 5,066,737, 5,763,723, 5,849,655, 5,852,144, 5,854,164, and 5,869,585; and published in EP-A2 0 416 815 A2 and EP-A1 0 420 436. Additional cocatalysts may be found in U.S. Pat. Nos. 3,221,002 and 5,093,415. Additionally, examples of supported catalyst systems are described in U.S. Pat. Nos. 4,701,432, 4,808,561, 4,912,075, 4,925,821, 4,937,217, 5,008,228, 5,238,892, 5,240,894, 5,332,706, 5,346,925, 5,422,325, and PCT Publication Nos. WO 95 / 32995, WO 95 / 14044, WO 96 / 06187, and WO 97 / 02297.

[0089] Polymer blends

[0090] In another embodiment, the polyethylene composition produced herein is combined with one or more additional polymers in the form of a blend and then formed into a film, molded part, or other article. As used herein, "blend" can refer to a dry or extruder blend of two or more different polymers, as well as an in-reactor blend, including blends produced by using multiple or mixed catalyst systems in a single reactor zone, and blends produced by using one or more catalysts in one or more reactors under the same or different conditions (e.g., blends produced by series reactors (same or different) each operating under different conditions and / or having different catalysts).

[0091] The one or more additional polymers may include polyethylene, isotactic polypropylene, highly isotactic polypropylene, syndiotactic polypropylene, random copolymers of propylene and ethylene, and / or butene, and / or hexene, polybutene, ethylene vinyl acetate, low density polyethylene (LDPE), linear low density polyethylene (LLDPE), high density polyethylene (HDPE), ethylene vinyl acetate, ethylene methyl acrylate, copolymers of acrylic acid, polymethyl methacrylate or any other polymer polymerizable by a high pressure free radical process, polyvinyl chloride, polybutene-1, isotactic polybutene, ABS resin, ethylene propylene rubber (EPR), sulfurized EPR, ethylene propylene diene monomer (EPDM) polymers, block copolymers, styrenic block copolymers, polyamides, polycarbonates, PET resins, cross-linked polyethylene, copolymers of ethylene and vinyl alcohol (EVOH), polymers of aromatic monomers such as polystyrene, poly-1 esters, polyacetals, polyvinylidene fluoride, polyethylene glycol, and / or polyisobutylene.

[0092] In some embodiments, one or more additional polymers are present in the above blend at from 0.1 wt % to 99 wt %, such as 0.1 wt % to 60 wt %, such as 0.1 wt % to 50 wt %, such as 1 wt % to 40 wt %, such as 1 wt % to 30 wt %, such as 1 wt % to 20 wt %, such as 1 wt % to 10 wt %, based on the weight of the polymer in the blend, and the rest is the polyethylene composition according to the above description.

[0093] The blends described above can be produced by mixing the polyethylene composition with one or more additional polymers (such as described immediately above), by connecting reactors together in series to prepare a reactor blend, or by using more than one catalyst in the same reactor to produce multiple polymers. The polymers can additionally or alternatively be mixed together as a post-reactor blend, for example, before being placed in an extruder, or can be mixed in an extruder.

[0094] The blends can be formed using conventional equipment and processes, such as by dry blending the individual components and then melt mixing in a mixer, or by mixing the components directly together in a mixer, such as, for example, a Banbury mixer, a Haake mixer, a Brabender internal mixer, or a single or twin screw extruder, which may include compounding extruders and side arm extruders used directly downstream of the polymerization process, which may include blending powders or pellets of the resin at the hopper of a film extruder.

[0095] additive

[0096] As desired, additives may be included in the polyethylene composition and / or blends comprising the polyethylene composition (such as those described above), one or more components of the blend, and / or products (such as films) formed from the polyethylene composition and / or blend. Such additives may include, for example: fillers; neutralizers (e.g., zinc oxide); antioxidants (e.g., hindered phenols such as IRGANOX available from Ciba-Geigy); TM 1010 or IRGANOX TM 1076); phosphites (e.g., IRGAFOS available from Ciba-Geigy TM 168); acid scavengers; processing oils (or other solvents); compatibilizers; lubricants (e.g., oleamide); anti-cling additives; tackifiers such as polybutene, terpene resins, aliphatic and aromatic hydrocarbon resins, alkali metal and stearyl glycerides, and hydrogenated resins; UV stabilizers; heat stabilizers; antiblocking agents; mold release agents; antistatic agents; pigments; colorants; dyes; waxes; silica; fillers; talc; etc.

[0097] The polyethylene compositions of the present disclosure may include additives such that the additives (e.g., fillers present in the composition) have an average aggregate size of less than 50 microns, such as less than 40 microns, such as less than 30 microns, such as less than 20 microns, such as less than 10 microns, such as less than 5 microns, such as less than 1 micron, such as less than 0.5 microns, such as less than 0.1 microns based on a 1 cm×1 cm cross-section of the cyclic polymer composition as observed using scanning electron microscopy.

[0098] In at least one embodiment, the polyethylene composition may include fillers and colorants. Exemplary materials include inorganic fillers, such as calcium carbonate, clay, silica, talc, titanium dioxide, or carbon black. Any suitable type of carbon black may be used, such as channel black, furnace black, thermal black, acetylene black, lamp black, etc.

[0099] In at least one embodiment, the polyethylene composition may include a flame retardant, such as calcium carbonate, an inorganic clay containing hydration water, such as aluminum trihydroxide ("ATH"), or magnesium hydroxide.

[0100] In at least one embodiment, the polyethylene composition may include a UV stabilizer, such as titanium dioxide or XT-850. The UV stabilizer can be introduced into the roofing composition as part of a masterbatch. For example, the UV stabilizer can be pre-blended into a masterbatch with a thermoplastic resin such as polypropylene or polyethylene (such as linear low density polyethylene).

[0101] Still other additives may include antioxidants and / or thermal stabilizers. In at least one embodiment, the processing and / or field thermal stabilizer may include the BASF-available B-225 and / or 1010.

[0102] In at least one embodiment, the polyethylene composition may include a polymer processing additive. The processing additive may be a polymer resin with a very high melt flow index. These polymer resins may include linear and / or branched polymers, which may have a melt flow rate of about 500 dg / min or greater, such as about 750 dg / min or greater, such as about 1000 dg / min or greater, such as about 1200 dg / min or greater, such as about 1500 dg / min or greater. A mixture of various side chains or various linear polymer processing additives, and a mixture of linear and branched polymer processing additives may be used. Unless otherwise indicated, the polymer processing additives mentioned may include both linear and branched additives. A linear polymer processing additive may include a polypropylene homopolymer, and a branched polymer processing additive may include a diene-modified polypropylene polymer. Similar processing additives are disclosed in U.S. Patent No. 6,451,915, which is incorporated herein by reference.

[0103] In some embodiments, fillers (such as calcium carbonate, clay, silica, talc, titanium dioxide, carbon black, nucleating agents, mica, wood flour, etc., and blends thereof, as well as inorganic and organic nanoscale fillers) may be present in the polyethylene composition in an amount from about 0.1 wt% to about 10 wt%, such as from about 1 wt% to about 7 wt%, such as from about 2 wt% to about 5 wt%, based on the total weight of the polyethylene composition. The amount of filler that can be used may depend at least in part on the type of filler and the amount of extender oil used.

[0104] In some embodiments, and when used, the polyethylene composition can include a processing additive (eg, a polymer processing additive) in an amount from about 0.1 wt% to about 20 wt%, based on the total weight of the polyethylene composition.

[0105] Membranes and their end uses

[0106] The polyethylene composition of the present disclosure can be used for forming operations such as film, sheet and fiber extrusion and coextrusion and blow molding, injection molding and rotational molding. Film includes blow molding or cast film formed by coextrusion or by lamination, which can be used as shrink film, cling film (cling film), stretch film, sealing film, oriented film, snack packaging, heavy-duty bags, grocery bags, baking and frozen food packaging, medical packaging, industrial lining, diaphragm (membrane) etc. in food contact and non-food contact applications. Fiber includes melt spinning, solution spinning and melt-blown fiber operations for weaving or nonwoven forms to manufacture filters, diaper fabrics, medical clothing, geotextiles etc. Extruded products include medical tubing, wire and cable coatings, pipelines, geomembranes and pond liners. Molded products include single-layer and multilayer structures in the form of bottles, cans, large hollow products, rigid food containers and toys.

[0107] The polyethylene composition can form a monolayer or multilayer film. These films can be formed by any conventional techniques, including extrusion, coextrusion, extrusion coating, lamination, blow molding and casting. The film can be obtained by a flat film or tubular process, which can then be oriented in the film plane in a uniaxial direction or in two mutually perpendicular directions. One or more layers of the film can be oriented in the horizontal and / or longitudinal directions to the same or different degrees. This orientation can occur before or after the individual layers are brought together.

[0108] As noted, the polyethylene compositions of the present disclosure can be particularly useful for making oriented PE film structures, such as uniaxially oriented (machine direction oriented, MDO) films and biaxially oriented PE (BOPE) films. Given their favorable strength and other properties, such films can be advantageously prepared using all-PE structures and formulations (e.g., without PET and other components that are difficult to recycle).

[0109] A method for producing a biaxially oriented polyethylene film may include: producing a polymer melt comprising the polyethylene composition described herein; extruding a film from the polymer melt; stretching the film in the machine direction at a temperature below the melting temperature of the polyethylene to produce a machine direction oriented (MDO) polyethylene film; and stretching the MDO polyethylene film in the transverse direction to produce a biaxially oriented polyethylene film.

[0110] The longitudinal stretching can be achieved by passing the film through a series of rollers, wherein the temperature and speed of a single roller are controlled to achieve the desired film thickness and the stretch ratio of MD stretching. Typically, this series of rollers is referred to as a part of the MDO section of MDO rollers or film production. Examples of MDO may include, but are not limited to, preheating rollers, various stretching sections with or without annealing rollers between sections, one or more conditioning and annealing rollers, and one or more cooling rollers. Film stretching in the MDO section is achieved by causing a speed difference between two or more adjacent rollers.

[0111] The stretch ratio of MD stretching can be used to describe the degree of stretching of the film. The stretch ratio is the speed of the fast roller divided by the speed of the slow roller. For example, stretching a film using an apparatus in which the slow roller speed is 1 m / min and the fast roller speed is 7 m / min means a stretch ratio of 7 (also referred to herein as 7 times or 7x). The physical quantity of film stretching is close to, but not exactly, the stretch ratio, because relaxation of the film occurs after stretching.

[0112] A larger stretch ratio for MD stretching results in a thinner film with greater orientation in the MD. The machine direction stretch ratio can be 1x to 10x (or 3x to 7x, or 5x to 9x, or 7x to 10x). One skilled in the art can determine, without undue experimentation, the appropriate temperature and roll speed for each roll in a given MDO stage of film production to produce the desired stretch ratio.

[0113] Transverse stretching can be achieved by pulling the film from the edges in a tenter, which is a series of moving clamps, as the film passes through the stretching zone of the TDO section oven. A TDO section oven typically has three zones: (1) a preheat zone to soften the film, (2) a stretch zone to stretch the film in the transverse direction, and (3) an annealing zone in which the stretched film is cooled and relaxed.

[0114] The stretch ratio of TD stretching can be used to describe the degree of film stretching performed using a tenter (compared to the roller speed when stretching along MD). The stretch ratio of TD stretching is the increase in the tenter width from the beginning to the end of stretching, and is calculated as the tenter width at the end of stretching divided by the initial tenter width, and can be reported as a number or multiple or multiple numbers, as in the case of MD stretching. The larger the stretch ratio of TD stretching, the thinner the film with greater orientation in TD. When the polyethylene film described herein is stretched in the transverse direction, the stretch ratio can be 1x to 12x (or 3x to 7x, or 5x to 9x, or 8x to 12x). Those skilled in the art can determine the appropriate temperature and tenter operating parameters in a given TDO section of film production without too much experimentation to produce the desired stretch ratio.

[0115] Polyethylene compositions according to those described herein can be stretched in the transverse and / or longitudinal directions over a wide temperature range. For example, the polyethylene can be stretched in the longitudinal direction over a temperature range of at least 3°C, preferably at least 6°C, preferably at least 7°C, preferably at least 8°C, preferably at least 10°C, preferably at least 12°C, alternatively from 3°C to 20°C, alternatively from 5°C to 15°C.

[0116] Likewise, the polyethylene composition can be stretched in the transverse direction in a temperature range of at least 3°C, at least 5°C, preferably at least 6°C, preferably at least 7°C, preferably at least 8°C, preferably at least 10°C, preferably at least 12°C, alternatively from 3°C to 20°C, alternatively from 3°C to 15°C, alternatively from 3°C to 10°C, alternatively from 3°C to 6°C.

[0117] Preferably, the film can be stretched in the transverse direction without tearing the web and without producing film thickness unevenness in a temperature range of at least 3°C, at least 5°C, preferably at least 6°C, preferably at least 7°C, preferably at least 8°C, preferably at least 10°C, preferably at least 12°C, alternatively from 3°C to 20°C, alternatively from 3°C to 15°C, alternatively from 3°C to 10°C, alternatively from 3°C to 6°C.

[0118] Preferably, the film can be stretched in the machine direction without web instabilities and large film thickness variations in a temperature range of at least 3° C., preferably at least 6° C., preferably at least 7° C., preferably at least 8° C., preferably at least 10° C., preferably at least 12° C., alternatively from 3° C. to 20° C., alternatively from 5° C. to 15° C. A wider stretching temperature range in both the MD and TD sections allows more flexibility in operating the machine in terms of achievable line speeds and stretch ratios.

[0119] The oriented (e.g., biaxially oriented) polyethylene films described herein can be used as a monolayer film or as one or more layers of a multilayer film. Examples of other layers include, but are not limited to, unstretched polymer films, MDO polymer films, and other oriented polymer films of polymers such as polyethylene, polypropylene, polyethylene terephthalate, polystyrene, polyamide, etc.

[0120] Similarly, the polyethylene composition according to any of the various embodiments can be used as part of a monolayer film of different types, or as one or more layers of a multilayer film (e.g., a non-BOPE film or even a non-oriented film). Any monolayer film (or any one or more layers of a multilayer film) can be formed from the polyethylene composition or a blend comprising the polyethylene composition, optionally with other formulation components (additives, other polymer materials, hydrocarbon resins, etc., as known in the art).

[0121] Specific end-use films include, for example, blown films, cast films, stretch films, stretch / cast films, stretch cling film, stretch hand wrap film, machine stretch wrap, shrink film, shrink wrap film, greenhouse film, laminates, and laminated films. Exemplary films are prepared by any conventional technique known to those skilled in the art, such as, for example, techniques for preparing blown, extruded, and / or cast stretch and / or shrink films (including shrink-to-shrink applications).

[0122] The oriented polyethylene films described herein (alone or as part of a multilayer film) and / or other films made from the polyethylene compositions described herein are useful end-use applications including, but not limited to, film-based products, shrink films, cling film, stretch film, sealing films, snack packaging, heavy-duty bags, grocery bags, baked and frozen food packaging, diaper backs, household wraps, medical packaging (e.g., medical films and intravenous (IV) bags), industrial liners, diaphragms, and the like.

[0123] These films may be further embossed, or produced or processed according to other known film processes. These films may be tailored for specific applications by adjusting the thickness, materials, and sequence of the various layers, as well as the additives or modifiers applied to each layer.

[0124] The thickness of the film can vary according to the intended application; however, films with a thickness of from 1 μm to 250 μm are generally suitable. The thickness of films intended for packaging is typically from 10 to 60 microns. The thickness of the sealing layer is typically from 0.2 μm to 50 μm. There can be a sealing layer on both the inner and outer surfaces of the film, or the sealing layer can be present only on the inner or outer surface. The thickness of films intended for heavier load applications (such as geomembranes) can be from 25 μm to 260 μm, such as from 25 μm to 130 μm, preferably from 50 μm to 110 μm.

[0125] In another embodiment, one or more layers may be modified by corona treatment, electron beam irradiation, gamma irradiation, or microwave irradiation.

[0126] Other products

[0127] Other examples of the desired articles made by the compositions of the present disclosure can include one or more of the following: sheets, fibers, weaving and nonwoven fabrics, automotive parts, furniture, sports equipment, food storage containers, transparent and translucent products, toys, tubing and pipelines, sheets, packaging, bags (bags), bags (sacks), coatings, lids, closures, crates, pallets, cups, non-food containers, barrels, insulating materials, and / or medical devices. Other examples include automotive parts, wire and cable sheaths, pipelines, agricultural films, geomembranes, toys, sports equipment, medical devices, casting and blowing of packaging films, extrusion of tubing, pipelines and profiles, outdoor furniture (e.g., garden furniture), playground equipment, boats and watercraft parts, and other such products. In particular, these compositions are suitable for automotive parts, such as bumpers, grilles, decorative parts, dashboards, instrument panels, outer doors and hood parts, spoilers, windshields, hubcaps, mirror housings, body panels, protective side moldings, and other interior and exterior parts relevant to automobiles, trucks, boats and other vehicles.

[0128] Other useful articles and items may include: crates, containers, packages, laboratory equipment such as roller bottles and media bottles for culture growth, office floor mats, instrument sample holders and sample windows; liquid storage containers such as bags, pouches and bottles for blood or solution storage and intravenous infusion; packaging materials, including those for medical devices or drugs, including unit dose or other blister or bubble packaging, and those for wrapping or containing foods preserved by irradiation. Other useful items include medical tubing and valves for any medical device (such medical devices include infusion sets, catheters and respiratory therapy devices), and packaging materials (including trays) for irradiated medical devices or foods, and stored liquid (such as water, milk or juice) containers (including unit portion and bulk storage containers), and transfer devices such as tubing and tubing.

[0129] Extrusion coating

[0130] Polyethylene compositions can be used in extrusion coating methods and applications. Extrusion coating is a plastic manufacturing method in which molten polymer is extruded and applied to a non-plastic carrier or substrate (such as paper or aluminum) to obtain a multi-material composite structure. This composite structure typically combines the toughness, sealing and impedance characteristics of a polymer formulation with the barrier, stiffness or aesthetic attributes of a non-polymer substrate. In this method, when polymer is extruded from a slot die, typically substrate is fed into the molten polymer from a roller, which is similar to the cast film method. The resulting structure is typically cooled with one or more chill rolls, and will become a finished product roll.

[0131] Extrusion coated materials are typically used in the manufacture of food and non-food packaging, pharmaceutical packaging, and articles for use in construction (insulation elements) and the photographic industry (paper).

[0132] Examples

[0133] Three exemplary ethylene-butene copolymers (IE1-3) of the present invention were prepared using ZN catalysts using two series slurry loop reactors according to the present disclosure to obtain polyethylene compositions IE1, IE2 and IE3, each having 55% LMWF (prepared in the first series reactor) and 45% HMWF (prepared in the second series reactor). After the polymerization process, the resulting slurry was separated from the diluent and dried. From there, the polymer was sent to the post-processing section. In this last section, the branching content was adjusted by post-reactor modification of the particles, and air was injected into the mixer (ZSK380 Kobe mixer with MaagGear Pump) at an air to production rate flow ratio of 0.21 lb air / lb PE (+ / - 50% range variation) and an orifice gate temperature of about 440±5°F. In addition, antioxidants and neutralizing additives were added to the product when the particles were post-processed into the final granular form.

[0134] Table 1 below provides the structural properties of IE1, IE2 and IE3 and comparative examples CE1, CE2, CE3, CE4 and CE5, wherein CE1, 4 and 5 are bimodal high density PE compositions, and CE2 and CE3 are unimodal high density PE compositions.

[0135] Table 1. Exemplary Polyethylene Composition Properties

[0136]

[0137]

[0138] As shown in Table 1, g' LCB It can be seen from the values ​​that IE1-3 all have a significantly higher degree of long-chain branching structure than the comparative resin, while also exhibiting an overall lower viscosity at higher shear rates, showing significant advantages in processing. Note that although the DST of IE1-3 is lower than some comparative examples, this is generally due to having a lower viscosity at the beginning at a low shear rate. And in any case, the favorable low viscosity of IE1-3 at high shear rates (e.g., 628 rad / s) is closer to the viscosity that may be encountered during extrusion and other processing. The favorable lower viscosity is also shown in Figures 1a and 1b. Each of those figures shows the complex viscosity of IE1-3 relative to frequency, wherein Figure 1a also shows comparative examples CE1 and CE2; and Figure 1b also shows comparative examples CE3, CE4 and CE5.

[0139] The unique combination of properties that lead to the superior processing of the inventive IE1-3 is further highlighted in the low ratios and width-to-height ratios reported in Table 1, where IE1-3 has significantly higher values ​​for each ratio than all other comparative examples. The meaning of each ratio is explained in the detailed description above.

[0140] Finally, in Figures 2a and 2b, we also report the molecular weight distribution of all samples, as determined by GPC according to the above specific embodiments. Figure 2a shows the inventive examples compared to CE1 and CE2; Figure 2b shows the inventive examples compared to CE3, CE4 and CE5. IE1-IE3 exhibit a fairly broad distribution with two discernible peaks, illustrating the multimodal nature of these polyethylene compositions. The significantly broader properties compared to CE1-CE5 also illustrate the excellent processing properties that can be expected from the inventive polyethylene compositions.

[0141] The examples of the present invention exhibit an excellent combination of properties, especially their Mz, g' LCB , Mz / Mn, Mw / Mn and the combination of viscosity under 628rad / s, confirm the good characteristics in terms of stiffness, heat resistance, etc., while providing a high degree of orientation (MD / TD stretch ratio) with uniform film thickness and a good degree of extrudability under low head pressure and competitive production line output. In short, they successfully balance the desired final film properties with excellent processing properties, and are therefore expected to be excellent candidates for applications such as BOPE films; in addition, considering their high-density properties and unique molecular design, they will provide significantly superior mechanical strength properties compared to their counterparts. It is unexpected and highly advantageous to achieve such good processing properties in such high-density, high-strength polyethylene compositions. The BOPE films made from such polyethylene compositions have opened up several favorable possibilities in the field of film making, wherein a specific example is a full PE film, which can replace the existing solutions using PP or PET and other materials, while maintaining the strength and barrier properties required for these films for end uses (such as food and other packaging applications).

[0142] Unless otherwise indicated, the phrases "consists essentially of" and "consisting essentially of" do not exclude the presence of other steps, elements, or materials, whether or not specifically mentioned in the specification, as long as such steps, elements, or materials do not affect the basic and novel characteristics of the disclosure, and further, they do not exclude impurities and differences normally associated with the elements and materials used.

[0143] For the sake of brevity, only certain ranges are explicitly disclosed herein. However, the range from any lower limit can be combined with any upper limit to list a range that is not explicitly listed, and the range from any lower limit can be combined with any other lower limit to list a range that is not explicitly listed, and in the same way, the range from any upper limit can be combined with any other upper limit to list a range that is not explicitly listed. In addition, each point or single value between its endpoints is included in a range, even if it is not explicitly listed. Therefore, each point or single value can be combined as its own lower limit or upper limit with any other point or single value or any other lower limit or upper limit to list a range that is not explicitly listed.

[0144] All documents described herein are incorporated herein by reference, including any priority documents and or test procedures, as long as they are not contrary to this article. As is apparent from the above general description and specific embodiments, although the form of the present disclosure has been illustrated and described, various modifications can be made without departing from the spirit and scope of the present disclosure. Therefore, it is not intended to limit the present disclosure thereby. Similarly, with respect to U.S. law, the term "comprising" is considered to be synonymous with the term "including". Similarly, whenever there is a transitional phrase "comprising" before a composition, an element or an element group, it should be understood that we have also contemplated the same composition or element group with a transitional phrase "essentially consisting of...", "consisting of...", "selected from a group consisting of...", or "is", and vice versa before the narration of the composition, one or more elements.

[0145] While the disclosure has been described with respect to a number of embodiments and examples, it will be appreciated by those skilled in the art, having benefit of this disclosure, that other embodiments can be devised which do not depart from the scope and spirit of the disclosure.

Claims

1. A polyethylene composition comprising: 80 wt% to 99.9 wt% ethylene content based on ethylene content plus comonomer content; 20 wt% to 0.1 wt% based on ethylene content plus comonomer content C3 to C 40 α-olefin comonomer content, wherein the C3 to C 40 The α-olefin comonomer is selected from 1-butene, 1-hexene, 1-octene, and combinations thereof; and wherein the polyethylene composition has the following characteristics: From 0.930 g / cm 3 Up to 0.975 g / cm 3 Density within the range of Mw / Mn of 10 or more; Mz of 800,000 g / mol or greater; Mz / Mn of 70 or greater; 0.75 or less g' LCB ; A low ratio greater than 0.03; and A width-to-height ratio greater than or equal to 0.2; The low ratio is defined as: where MI is the melt index (g / 10 min, at 2.16 kg, 190 °C); η 628 is the complex viscosity at 628 rad / s (in Pa*s); Mn is the number average molecular weight (g / mol); and g' LCB is the long-chain branching index; The aspect-to-height ratio is defined as: where Mz and Mn are the z-average molecular weight and number-average molecular weight (g / mol), respectively; HLMI is the high load melt index (g / 10 min at 21.6 kg and 190 °C); η 0.01 is the complex viscosity at 0.01 rad / s (in Pa*s); and g' LCB is the long-chain branching index; And wherein the polyethylene composition exhibits a bimodal molecular weight distribution as determined by GPC.

2. The polyethylene composition of claim 1, wherein: Density from 0.935 to 0.970 g / cm 3 within the scope of Mw / Mn is 12 or greater; Mz is 900,000 g / mol or greater; Mz / Mn is 85 or greater; and g' LCB is 0.70 or less.

3. The polyethylene composition of claim 1 or claim 2, further having the following characteristics: Mw in the range from 120,000 to 180,000 g / mol; and Mn in the range from 8,000 to 15,000 g / mol.

4. The polyethylene composition of claim 1 or claim 3, further having the following characteristics: MI (2.16 kg, 190 °C) in the range from 0.5 to 1.0 g / 10 min; HLMI (21.6 kg, 190°C) in the range from 30 to 70 g / 10 min; MIR (HLMI / MI) in the range from 30 to 140.

5. The polyethylene composition of claim 1 or claim 3, further having the following characteristics: Degree of shear thinning (DST) in the range from 0.930 to 0.970; complex viscosity at 628 rad / s in the range from 300 to 400 Pa*s; and Complex viscosity at 0.01 rad / s in the range from 20,000 to 35,000 Pa*s.

6. The polyethylene composition of claim 1, having a low ratio ranging from 0.031 to 0.

6.

7. The polyethylene composition of claim 1, having a width-to-height ratio in the range of from 0.20 to 6.

0.

8. The polyethylene composition according to claim 1 or claim 2, wherein: The polyethylene composition comprises from 50.1 wt% to 59 wt% of a low molecular weight fraction (LMWF) and from 41 wt% to 49.9 wt% of a high molecular weight fraction (HMWF), wherein the LMWF has a higher density than the HMWF.

9. A polyethylene composition having a molecular weight of from 0.930 g / cm 3 Up to 0.975 g / cm 3 and comprising from 98 wt% to 99.9 wt% of units derived from ethylene and the balance derived from units of a comonomer selected from 1-butene, 1-hexene and 1-octene, the wt% being based on the ethylene content plus the comonomer content; Further wherein the polyethylene composition has the following characteristics: (a) a low ratio greater than 0.03, wherein the low ratio is defined as: where MI is the melt index (g / 10 min, at 2.16 kg, 190 °C); η 628 is the complex viscosity at 628 rad / s (in Pa*s); Mn is the number average molecular weight (g / mol); and g' LCB is the long chain branching index; and (b) an aspect ratio greater than or equal to 0.2, wherein the aspect ratio is defined as: where Mz and Mn are the z-average molecular weight and number-average molecular weight (g / mol), respectively; HLMI is the high load melt index (g / 10 min at 21.6 kg and 190 °C); η 0.01 is the complex viscosity at 0.01 rad / s (in Pa*s); and g' LCB is the long-chain branching index; And wherein the polyethylene composition exhibits a bimodal molecular weight distribution as determined by GPC.

10. The polyethylene composition of claim 9 having both a low ratio in the range of from 0.031 to 0.05 and a width-to-height ratio in the range of from 0.20 to 6.

0.

11. The polyethylene composition of claim 9 or claim 10, further having one or more of the following characteristics: (a) Mw in the range of from 120,000 to 180,000 g / mol; (b) Mn in the range from 8,000 to 15,000 g / mol; (c) MI (2.16 kg, 190 °C) in the range from 0.5 to 1.0 g / 10 min; (d) HLMI (21.6 kg, 190 °C) in the range from 30 to 70 g / 10 min; (e) MIR (HLMI / MI) in the range of 30 to 140; and (f) Degree of shear thinning (DST) in the range from 0.930 to 0.

970.

12. The polyethylene composition of claim 11 having all of the properties (a) to (f).

13. A film comprising the polyethylene composition of claim 1 or claim 9.

14. The film of claim 13, wherein The film is a uniaxially or biaxially oriented polyethylene film.

15. The film of claim 14, wherein The film is a multilayer film.

16. The film of claim 13, wherein The film is a multilayer film and at least one layer comprises a biaxially oriented polyethylene film layer comprising the polyethylene composition.

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