Polyethylene compositions suitable for use in cast stretched films

Abstract

Provided are polyethylene compositions and cast-oriented films comprising the polyethylene compositions. The cast-oriented films can exhibit improved tear strength and palletizing benefits while maintaining other properties. The cast-oriented films can also be fully compatible with polyethylene recycle streams and can be polypropylene-free.

Description

[Technical Field]

[0001] Embodiments of this disclosure generally relate to polyethylene compositions, and more specifically, polyethylene compositions suitable for use in cast stretched films.

[0002] Introduction Cast-stretched films are highly transparent films used to protect and integrate manufactured goods or items for transport and storage. It is highly desirable for cast-stretched films to have high transverse tear strength to minimize catastrophic damage during wrapping on pallets. To increase transverse tear strength, cast-stretched films are often formed from polyolefins, including a mixture of polypropylene and polyethylene, with polypropylene added, for example, to improve tear performance. Such films are difficult to manufacture and, due to the different mixtures of incompatible recyclable materials (i.e., polypropylene and polyethylene), recycling them together can be difficult, if not impossible. As the demand for sustainable and recyclable materials continues to grow, there remains a strong need for polyethylene compositions that can form cast-stretched films with improved tear strength while maintaining other properties such as stretchability and puncture resistance. [Overview of the project]

[0003] Embodiments of the present disclosure satisfy the aforementioned requirements by providing a polyethylene composition that can be used to form a cast-stretched film that is fully recyclable in a polyethylene recycling stream and exhibits improved tear strength characteristics. The performance of the film of the present invention may be better than that of other cast-stretched films, such as cast-stretched films containing polyethylene, and can offer better advantages, for example, on pallets.

[0004] This specification discloses polyethylene compositions. In embodiments, the polyethylene composition is characterized by having the following: (a) 0.910 to 0.945 g / cm³ 3 (b) density of 0.5–7.0 g / 10 min melt index (I2), (c) a first polyethylene fraction having a single peak in the temperature range of 40°C–85°C in the elution profile by improved comonomer composition distribution (iCCD) analysis, (d) a second polyethylene fraction having a single peak in the temperature range of 90°C–115°C in the elution profile by iCCD analysis, wherein the second polyethylene area fraction is the area of ​​the elution profile directly below the peak of the second polyethylene fraction in the 90°C–115°C range, the second polyethylene area fraction constitutes at least 30% of the total area of ​​the elution profile, and the width at the 50 percent peak height of the peak of the second polyethylene fraction is less than 4.0°C, and (e) molecular weight comonomer distribution index (MWCDI) value less than 0.

[0005] Furthermore, cast stretched films are also disclosed herein. In embodiments, the cast stretched film comprises a polyethylene composition characterized by having the following: (a) 0.910 to 0.945 g / cm 3 (b) density of 0.5 to 7 g / 10 min melt index (I2), (c) a first polyethylene fraction having a single peak in the temperature range of 40°C to 85°C in the elution profile by improved comonomer composition distribution (iCCD) analysis, (d) a second polyethylene fraction having at least one peak in the temperature range of 90°C to 115°C in the elution profile by iCCD analysis, wherein the second polyethylene area fraction is the area of ​​the elution profile directly below the peak of the second polyethylene fraction in the 90°C to 115°C range, and the second polyethylene area fraction constitutes at least 30% of the total area of ​​the elution profile, and (e) MWCDI value less than 0.

[0006] These and other embodiments are described in more detail in “Modes for Carrying Out the Invention.” [Brief explanation of the drawing]

[0007] [Figure 1] A schematic representation of the iCCD elution profile is shown. [Figure 2] This is a diagram illustrating the data flow of a dual parallel reactor. [Figure 3] This is a diagram illustrating the data flow of a double series reactor. [Figure 4] This is the iCCD elution profile of Poly.1 in the example. [Figure 5] This is the GPC overlay for Poly.1 in the example. [Modes for carrying out the invention]

[0008] Herein, specific embodiments of this application are described. However, this disclosure may be embodied in different forms and should not be construed as being limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure may be thorough and complete and so as to convey the scope of the subject matter to those skilled in the art.

[0009] Stretched films are a name given to polyolefin films that can be cold-stretched longitudinally and / or transversely without the application of heat, and that can maintain tension for extended periods when stretched around a load. Cast stretched films can be distinguished from inflation stretched films by their manufacturing method. The main differences between cast films and inflation stretched films relate to the cooling method, film orientation, line speed, and gauge control. Cast films typically exhibit better optical properties and a much higher degree of mechanical orientation compared to inflation stretched films. The novel cast stretched films and film structures described herein can be manufactured using conventional cast film manufacturing techniques.

[0010] As used herein, the term “polymer” means a polymer compound prepared by polymerizing monomers, whether of the same or different types. Thus, the general term “polymer” encompasses the terms homopolymer (used to refer to a polymer prepared from only one type of monomer) and copolymer or interpolymer. Trace amounts of impurities (e.g., catalyst residue) may be introduced into and / or within the polymer. A polymer may be a single polymer, a polymer blend, or a polymer mixture containing a mixture of polymers formed in situ during polymerization.

[0011] As used herein, the terms “polyethylene” or “ethylene-based polymer” shall mean a polymer containing units derived from a majority (>50 mol%) of ethylene monomers. This includes polyethylene homopolymers or copolymers (meaning units derived from two or more comonomers).

[0012] The terms “comprising,” “including,” and “having,” and their derivatives, are not intended to exclude the presence of any additional components, processes, or procedures, whether or not they are specifically disclosed. To avoid any doubt, all compositions claimed through the use of the term “comprising” may include any additional additives, adjuvants, or compounds, whether polymeric or otherwise, unless otherwise stated. In contrast, the term “consisting essentially of” excludes any other components, processes, or procedures from the scope of any subsequent description, except those not essential to operability. The term “consisting of” excludes any components, processes, or procedures not specifically described or listed.

[0013] Polyethylene composition This specification discloses a polyethylene composition. In an embodiment, the polyethylene composition is characterized by having a density of 0.910 to 0.945 g / cm 3 All individual values and sub-ranges of 0.910 to 0.945 g / cm 3 are disclosed and included herein. For example, the polyethylene composition can have a density of 0.910 to 0.940 g / cm 3 0.910 to 0.935 g / cm 3 0.910 to 0.930 g / cm 3 0.910 to 0.925 g / cm 3 0.915 to 0.945 g / cm 3 0.915 to 0.940 g / cm 3 0.915 to 0.935 g / cm 3 0.915 to 0.930 g / cm 3 0.915 to 0.925 g / cm 3 or 0.915 to 0.920 g / cm 3 .

[0014] In an embodiment, the polyethylene composition is also characterized by having a melt index (I2) of 0.5 to 7.0 g / 10 min. All individual values and sub-ranges of 0.5 to 7.0 g / 10 min are disclosed and included herein. For example, the polyethylene composition can have a melt index (I2) of 0.5 to 6.0 g / 10 min, 0.5 to 4.0 g / 10 min, 0.5 to 2.0 g / 10 min, 0.8 to 6.0 g / 10 min, 0.8 to 4.0 g / 10 min, 0.8 to 2.0 g / 10 min, 0.8 to 1.8 g / 10 min, 1.0 to 7.0 g / 10 min, 1.0 to 6.0 g / 10 min, 1.0 to 4.0 g / 10 min, or 1.0 to 2.0 g / 10 min.

[0015] In embodiments, the polyethylene composition is also characterized by having a first polyethylene fraction and a second polyethylene fraction. As described herein, polyethylene “fraction” refers to a portion of the overall composition of the polyethylene composition. Embodiments disclosed herein include at least a “first polyethylene fraction” and a “second polyethylene fraction.” Fractions contained in the polyethylene composition can be quantified by their temperature range in the elution profile by improved comonomer composition distribution (iCCD) analysis. Unless otherwise specified, any elution profiles referred to herein are elution profiles observed by iCCD. Examples of such fractions will be better understood by considering the examples provided herein. Generally, the first fraction may contain a single peak in the temperature range of the first fraction, and the second fraction may contain a single peak in the temperature range of the second fraction. The polyethylene compositions described herein may be referred to as “multimodal,” meaning that the polyethylene composition contains at least two peaks in their elution profile. Some embodiments may be “bimodal,” meaning that there are two main peaks.

[0016] Referring to the iCCD distribution described herein, Figure 1 schematically shows the iCCD distribution 100 of a sample, along with a cumulative weight fraction curve 200. Figure 1 shows some features of the iCCD profile of the polyethylene composition described herein, such as the first fraction, the second fraction, and the half-peak width, which are generally discussed in detail herein. Thus, Figure 1 can be used as a reference with respect to disclosures relating to the iCCD profile provided herein. Specifically, the first fraction 102 and the second fraction 106 are illustrated. The first fraction 102 has a peak 104, and the second fraction 106 has a peak 108. Each fraction has half-peak widths (i.e., width at 50 percent peak height) 110 and 112. It should be understood that the profiles in Figure 1 are not derived from experiments or observations, but are instead provided for informational purposes to describe certain features of the iCCD elution profile.

[0017] In some embodiments, the polyethylene composition is characterized by having a first polyethylene fraction. The first polyethylene fraction may have a single peak in the temperature range of 40°C to 85°C in the elution profile obtained by iCCD analysis. As used herein, “single peak” refers to an iCCD in which a particular fraction contains only a single peak. That is, in some embodiments, the iCCDs of the first and second polyethylene fractions contain only a downward slope region following an upward slope region in order to form a single peak. It should be understood that the peak in the first or second polyethylene fraction may not be formed by a local minimum in each polyethylene fraction at a defined temperature boundary. In other words, the peak must be a peak in terms of its entire range, not a peak formed by the threshold temperature of the polyethylene fraction. For example, if a polyethylene fraction has a single peak followed by a single trough (upward slope followed by downward slope followed by upward slope), then such a polyethylene fraction will have only a single peak.

[0018] In embodiments, the polyethylene composition is characterized by having a second polyethylene fraction. The second polyethylene fraction may have a single peak in the temperature range of 90°C to 115°C in the elution profile by iCCD analysis. In embodiments, the width at the 50 percent peak height of the single peak of the second polyethylene fraction may be less than 4.0°C, less than 3.5°C, less than 3.0°C, or even less than 2.5°C. Generally, a smaller temperature range at the 50 percent peak height corresponds to a "sharper" peak. While not bound by any particular theory, "sharper" or "narrower" peaks are thought to be features produced by molecular catalysis, indicating minimal comonomer incorporation in a higher density fraction and allowing for higher density separation between the two fractions.

[0019] In this embodiment, the first polyethylene area fraction is the area of ​​the elution profile directly below the single peak of the first polyethylene fraction at 40°C to 85°C. Similarly, the second polyethylene area fraction is the area of ​​the elution profile directly below the single peak of the second polyethylene fraction at 90°C to 115°C. The first and second polyethylene area fractions may each correspond to the total relative mass of each polymer fraction in the polyethylene composition. In this embodiment, the second polyethylene area fraction constitutes at least 30% of the total area of ​​the elution profile. For example, the second polyethylene area fraction may constitute at least 30%, at least 32%, at least 33%, at least 35%, at least 40%, at least 45%, at least 50%, at least 55%, or even at least 60% of the total area of ​​the iCCD elution profile, or it may constitute 30% to 65%, 30% to 60%, 30% to 55%, 30% to 50%, 35% to 65%, 35% to 50%, 40% to 65%, or 40% to 60% of the total area of ​​the elution profile.

[0020] In embodiments, the second polyethylene fraction of the polyethylene composition may have a weight-average molecular weight (Mw) of at least 95,000 g / mol. All individual values ​​and subranges of at least 95,000 g / mol are disclosed and included herein. For example, the second polyethylene fraction may have a weight-average molecular weight (Mw) of at least 95,000 g / mol, at least 100,000 g / mol, at least 120,000 g / mol, at least 160,000 g / mol, or at least 200,000 g / mol, or a weight-average molecular weight (Mw) in the range of 95,000 g / mol to 260,000 g / mol, 100,000 g / mol to 250,000 g / mol, or 100,000 g / mol to 220,000 g / mol. The molecular weight of the polyethylene fraction can be calculated based on GPC results, as described later herein.

[0021] In embodiments, the polyethylene composition is also characterized by having a molecular weight comonomer distribution index (MWCDI) of less than 0. All individual values ​​and subranges less than 0 are disclosed and incorporated herein. For example, a polyethylene composition may have an MWCDI of less than 0, less than -1, less than -2, less than -3, less than -4, less than -5, or less than -6, or an MWCDI in the range of 0 to -15, -1 to -12, -2 to -10, or -3 to -8, and the MWCDI may be measured according to the test methods described below.

[0022] In embodiments, the polyethylene composition may further be characterized by having a molecular weight distribution in the range of 2.0 to 8.0, expressed as the ratio of weight-average molecular weight to number-average molecular weight (Mw / Mn). In further embodiments, the molecular weight distribution (Mw / Mn) may be 2.0 to 7.0, 2.0 to 6.0, 2.0 to 5.0, 2.5 to 7.0, 2.5 to 6.0, or 2.5 to 5.0. The molecular weight distribution (Mw / Mn) of the polyethylene composition can be calculated based on GPC as described later herein.

[0023] In embodiments, the polyethylene composition may be further characterized by having a zero shear viscosity ratio (ZSVR) of less than 3.0. For example, the polyethylene composition may have a zero shear viscosity ratio of less than 2.9, less than 2.8, less than 2.7, less than 2.6, less than 2.5, less than 2.4, less than 2.3, less than 2.2, less than 2.1, less than 2.0, less than 1.9, less than 1.8, less than 1.7, less than 1.6, less than 1.5, less than 1.4, less than 1.3, less than 1.2, or even less than 1.1. In one or more embodiments, the polyethylene composition may have a zero shear viscosity ratio of at least 1.0. The ZSVR of the polyethylene composition can be measured according to the test methods described later herein.

[0024] A blend or mixture of the polyethylene composition with other polyolefins may be formed. Suitable polymers for blending with the polyethylene composition of the present invention include thermoplastic and non-thermoplastic polymers, including natural and synthetic polymers. Exemplary polymers for blending include polypropylene (both impact-modified polypropylene, isotactic polypropylene, atactic polypropylene, and random ethylene / propylene copolymers), various types of polyethylene (PE), such as high-pressure free-radical low-density polyethylene (LDPE), Ziegranata linear low-density polyethylene (LLDPE), and metallocene PE including multiple reactor PE ("in-reactor" blends of Ziegranata PE and metallocene PE, e.g., U.S. Patent No. 6,545,088 (Kolthammer et al.), U.S. Patent No. 6,538,070 (Cardwell et al.), U.S. Patent No. 6,566,446 (Parikh et al.), U.S. Patent No. 5,844,045 (Kolthammer et al.), U.S. Patent Examples of products disclosed in U.S. Patent No. 5,869,575 (Kolthammer et al.) and U.S. Patent No. 6,448,341 (Kolthammer et al.) include ethylene-vinyl acetate (EVA), ethylene / vinyl alcohol copolymers, polystyrene, impact-modified polystyrene, acrylonitrile-butadiene-styrene (ABS), styrene / butadiene block copolymers and their hydrogenated derivatives (styrene-butadiene-styrene (SBS) and styrene-ethylene-butadiene-styrene (SEBS)), and thermoplastic polyurethanes. Homogeneous polymers, such as olefin plastomers and elastomers, and ethylene-propylene copolymers (e.g., polymers available under trade names such as VERSIFY® Plastoms & Elastomers (The Dow Chemical Company), SURPASS® (Nova Chemicals), and VISTAMAXX® (ExxonMobil Chemical Co.)) may also be useful as components in blends containing the polyethylene compositions of the present invention.Suitable polymers for mixing with the polyethylene compositions disclosed herein include, in embodiments, LDPE and LLDPE such as AGILITY 1200 (manufactured by The Dow Chemical Company).

[0025] In embodiments, the polyethylene compositions of the present disclosure may further include 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 TiO2 or CaCO3, opacifiers, nucleating agents, processing aids, pigments, primary antioxidants, secondary antioxidants, UV stabilizers, antiblocking agents, slip agents, tackifiers, flame retardants, antimicrobial agents, odor reducers, antifungal agents, and combinations thereof. Based on the weight of the polyethylene composition containing such additives, the polyethylene composition may contain such additives in an amount of about 0.1 to about 10 weight percent by total weight.

[0026] In some embodiments, the first polyethylene fraction of the polyethylene composition may be formed in the presence of a first molecular catalyst, and the second polyethylene fraction of the polyethylene composition may be formed in the presence of a second molecular catalyst. The first and second molecular catalysts may be the same catalyst or different catalysts. In other embodiments, the first polyethylene fraction of the polyethylene composition may be formed in the presence of a molecular catalyst, and the second polyethylene fraction of the polyethylene composition may be formed in the presence of a Ziegranata catalyst. Polymerization and catalyst systems for forming polyethylene compositions according to the embodiments disclosed herein are described in more detail below. Generally, the molecular catalyst is a homogeneous polymerization catalyst comprising (a) a transition metal, (b) one or more unsubstituted or substituted cyclopentadienyl ligands, and / or (c) one or more ligands containing at least one heteroatom such as oxygen, nitrogen, phosphorus, and / or sulfur. The molecular catalyst can be immobilized on an inorganic support such as silica, alumina, or MgCl2.

[0027] polymerization Any conventional polymerization process may be used to produce the polyethylene compositions described herein. Such conventional polymerization processes include, but are not limited to, slurry polymerization processes and solution polymerization processes using one or more conventional reactors, such as loop reactors, isothermal reactors, stirred-tank reactors, parallel or continuous batch reactors, and / or any combination thereof. Polyethylene compositions may be produced, for example, via a solution-phase polymerization process using one or more loop reactors, isothermal reactors, and combinations thereof.

[0028] Generally, solution-phase polymerization processes can be carried out in one or more well-agitated reactors, such as one or more isothermal loop reactors or one or more adiabatic reactors, at temperatures in the range of 115–250°C (e.g., 115–210°C) and pressures in the range of 300–1,000 psi (e.g., 400–800 psi). In some embodiments, in a double reactor, the temperature in the first reactor is in the range of 115–190°C (e.g., 160–180°C), and the temperature in the second reactor is in the range of 150–250°C (e.g., 180–220°C). In other embodiments, in a single reactor, the reactor temperature is in the range of 115–250°C (e.g., 115–225°C).

[0029] The residence time in the solution-phase polymerization process can be in the range of 2 to 30 minutes (e.g., 5 to 25 minutes). Ethylene, solvent, hydrogen, one or more catalyst systems, optionally one or more co-catalysts, and optionally one or more comonomers are continuously supplied to one or more reactors. Examples of 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 polyethylene composition and solvent is then removed from the reactor, and the polyethylene composition is isolated. The solvent is typically recovered via a solvent recovery unit, such as a heat exchanger and a gas-liquid separator drum, and then recycled back into the polymerization system.

[0030] In some embodiments, the polyethylene composition may be produced by solution polymerization in a double reactor system, such as a double-loop reactor system, in the presence of one or more catalyst systems. In some embodiments, only ethylene is polymerized. In addition, one or more co-catalysts may be present. In another embodiment, the polyethylene composition may be produced by solution polymerization in a single reactor system, such as a single-loop reactor system, where ethylene is polymerized in the presence of two catalyst systems. In some embodiments, only ethylene is polymerized.

[0031] Catalyst system Herein, specific embodiments of catalyst systems that may be used in one or more embodiments to produce the polyethylene compositions described herein are described. It should be understood that the catalyst systems of this disclosure may be embodied in different forms and should not be construed as being limited to the specific embodiments described herein. Rather, the embodiments are provided so that this disclosure is thorough and complete and fully conveys the scope of the subject matter to those skilled in the art.

[0032] The term "independently selected" is used in R 1 , R 2 , R 3 , R 4 , and R 5 The R groups, such as R, may be the same or different (for example, R 1 , R 2 , R 3 , R 4 , and R 5 However, all are substituted alkyls, or R 1 and R 2 However, it is a substituted alkyl, and R 3 The term R is used herein to indicate that, for example, it may be an aryl group. The use of the singular form includes the use of the plural form, and vice versa (for example, hexane solvent contains multiple hexanes). A named R group will generally have a structure that is recognized in the art as corresponding to the R group bearing that name. These definitions are intended to supplement and illustrate, and not to exclude, definitions known to those skilled in the art.

[0033] The term "procatalyst" refers to a compound that exhibits catalytic activity when combined with an activator. The term "activator" refers to a compound that chemically reacts with a procatalyst to convert it into a catalytically active catalyst. As used herein, the terms "co-catalyst" and "activator" are interchangeable.

[0034] When used to describe a specific carbon-carbon-containing chemical group, "(C x ~C y The parenthetical expression in the form of ")" means that the unsubstituted form of the chemical group has x carbon atoms to y carbon atoms, including x and y. For example, (C1~C 40 ) Alkyl is an alkyl group having 1 to 40 carbon atoms in its unsubstituted form. In some embodiments and general structures, certain chemical groups are R S It can be replaced by one or more substituents such as (C x ~C y The chemical group R defined using ) S The substitution version is based on any base R S Depending on what it is, it may contain more than y carbon atoms. For example, "R S The group R is exactly one group, which is phenyl (-C6H5). S Replaced with (C1~C 40 )alkyl can contain 7 to 46 carbon atoms. Therefore, generally, the parenthetical "(C x ~C y A chemical group defined using ) is a substituent containing one or more carbon atoms R S When substituted by, the minimum and maximum total number of carbon atoms in the chemical group is, for both x and y, all carbon-carbon-containing substituents R S It is determined by adding up the total number of carbon atoms from which it originates.

[0035] The term "substituted" means that at least one hydrogen atom (-H) bonded to a carbon or heteroatom of the corresponding unsubstituted compound or functional group is a substituent (e.g., R SThis means that all hydrogen atoms (H) bonded to the carbon or heteroatom of the corresponding unsubstituted compound or functional group are substituted by substituents (e.g., R S This means that the atoms are replaced by the substituents. The term "polysubstituted" means that at least two, but fewer than all, hydrogen atoms bonded to the carbon or heteroatom of the corresponding unsubstituted compound or functional group are replaced by the substituents.

[0036] The term "-H" refers to hydrogen or a hydrogen radical covalently bonded to another atom. "Hydrogen" and "-H" are interchangeable and refer to the same thing unless otherwise specified.

[0037] (C1~C 40 The term "hydrocarbyl" refers to a hydrocarbon radical consisting of 1 to 40 carbon atoms. 40 The term "hydrocarbylene" means a hydrocarbon diradical having 1 to 40 carbon atoms, and each hydrocarbon radical and each hydrocarbon diradical is aromatic or non-aromatic, saturated or unsaturated, linear or branched, cyclic (monocyclic and polycyclic, condensed and non-condensed polycyclic including bicyclic, with 3 or more carbon atoms) or acyclic, unsubstituted or with one or more R S It has been replaced by.

[0038] In this disclosure, (C1~C 40 Hydrocarbyl is either unsubstituted or substituted (C1~C 40 ) alkyl, (C3~C 40 )Cycloalkyl, (C3~C 20 )Cycloalkyl-(C1~C 20 ) Alkilen, (C6~C 40 )aryl, or (C6~C 20 )Aaryl-(C1~C 20 ) may be alkylene. In some embodiments, the above (C1~C 40 Each of the hydrocarbyl groups has up to 20 carbon atoms (i.e., (C1~C 20(Hydrocarbyl), in other embodiments, having up to 12 carbon atoms.

[0039] (C1~C 40 )alkyl" and "(C1~C 18 The term "alkyl" means that each is either unsubstituted or has one or more R S This refers to saturated linear or branched hydrocarbon radicals consisting of 1 to 40 carbon atoms or 1 to 18 carbon atoms substituted by (C1-C). 40 Examples of alkyl groups include 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~C 40 Examples of alkyl groups include substitutions (C1~C 20 ) alkyl, substituted (C1~C 10 ) alkyl, trifluoromethyl, and [C 45 It is alkyl. [C 45 The term ]alkyl (in square brackets) means that there are up to 45 carbon atoms in the radical, including substituents, for example, one R is (C1-C5)alkyl. S Replaced by (C 27 ~C 40 Each (C1-C5) alkyl group may be methyl, trifluoromethyl, ethyl, 1-propyl, 1-methylethyl, or 1,1-dimethylethyl.

[0040] (C6~C 40 The term "aryl" refers to a group of 6 to 40 carbon atoms that are either unsubstituted or substituted (one or more R) S(by) means monocyclic, bicyclic, or tricyclic aromatic hydrocarbon radicals, of which at least 6 to 14 carbon atoms are aromatic ring carbon atoms, and monocyclic, bicyclic, or tricyclic radicals each contain 1, 2, or 3 rings, where the monocyclic ring is aromatic, and the 2 or 3 rings are independently condensed or uncondensed, and at least one of the 2 or 3 rings is aromatic. Unsubstituted (C6~C 40 Examples of aryls include unsubstituted (C6~C 20 ) Aryl, unsubstituted (C6~C 18 Examples include aryl, 2-(C1~C5)alkylphenyl, 2,4-bis(C1~C5)alkylphenyl, phenyl, fluorenyl, tetrahydrofluorenyl, indacenyl, hexahydroindacenyl, indenyl, dihydroindenyl, naphthyl, tetrahydronaphthyl, and phenanthrene. Substitutions (C6~C 40 ) An example of an aryl substitution is (C1~C 20 ) Aryl, substitution (C6~C 18 )aryl, 2,4-bis[(C 20 Examples include alkyl-phenyl, polyfluorophenyl, pentafluorophenyl, and fluoren-9-on-1-yl.

[0041] (C3~C 40 The term "cycloalkyl" refers to unsubstituted or one or more R S This refers to saturated cyclic hydrocarbon radicals of 3 to 40 carbon atoms substituted with (C). Other cycloalkyl groups (e.g., (C) x ~C y A cycloalkyl group has x to y carbon atoms and is either unsubstituted or has one or more R atoms. S Defined in a similar manner as either being replaced by (C3~C). Non-replaced (C3~C 40 Examples of cycloalkyl groups include unsubstituted (C3~C) 20 )Cycloalkyl, unsubstituted (C3~C 10 These are cycloalkyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, and cyclodecyl. Substitutions (C3~C 40)Examples of cycloalkyl include substituted (C3 - C 20 )cycloalkyl, substituted (C3 - C 10 )cycloalkyl, cyclopentanone - 2 - yl, and 1 - fluorocyclohexyl.

[0042] (Examples of (C1 - C 40 )hydrocarbylene 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 diradical is on the same carbon atom (e.g., -CH2-), or on adjacent carbon atoms (i.e., 1,2 - diradical), or separated by one, two, or more intervening carbon atoms (e.g., each 1,3 - diradical, 1,4 - diradical, etc.). Some diradicals include α,ω - diradicals. An α,ω - diradical is a diradical having the maximum carbon skeleton spacing between the radical carbons. Some examples of (C2 - C 20 )alkylene α,ω - diradicals include ethane - 1,2 - diyl (i.e., -CH2CH2-), propane - 1,3 - diyl (i.e., -CH2CH2CH2-), 2 - methylpropane - 1,3 - diyl (i.e., -CH2CH(CH3)CH2-). Some examples of (C6 - C<00,00098>)arylene α,ω - diradicals include phenyl - 1,4 - diyl, naphthalene - 2,6 - diyl, or naphthalene - 3,7 - diyl.

[0043] The term “(C1 - C 40 )alkylene” means an unsubstituted or one or more R S substituted saturated straight - chain or branched - chain diradical of 1 to 40 carbon atoms (i.e., the radicals are not on ring atoms). Unsubstituted (C1 - C 50Examples of alkylenes include unsubstituted -CH2CH2-, -(CH2)3-, -(CH2)4-, -(CH2)5-, -(CH2)6-, -(CH2)7-, -(CH2)8-, and -CH2C. * HCH3 and -(CH2)4C * (H)(CH3) and unsubstituted (C1~C 20 ) is an alkylene, and in the formula, "C * " indicates a carbon atom from which a hydrogen atom has been removed, forming a secondary or tertiary alkyl radical. Substitution (C1~C 50 ) An example of alkylene is substitution (C1~C 20 ) Alkylene, -CF2-, -C(O)-, and -(CH2) 14 It is C(CH3)2(CH2)5- (i.e., 6,6-dimethyl-substituted n-1,20-eicosylene). As mentioned above, there are two R S Together, (C1~C 18 ) Because alkylenes can be formed, substitution (C1~C 50 Examples of alkylenes include 1,2-bis(methylene)cyclopentane, 1,2-bis(methylene)cyclohexane, 2,3-bis(methylene)-7,7-dimethyl-bicyclo[2.2.1]heptane, and 2,3-bis(methylene)bicyclo[2.2.2]octane.

[0044] (C3~C 40 The term "cycloalkylene" refers to an unsubstituted or one or more R S This refers to a cyclic diradical of 3 to 40 carbon atoms substituted by (i.e., the radical lies on the ring atom).

[0045] The term "heteroatom" refers to an atom other than hydrogen or carbon. Examples of heteroatoms include O, S, S(O), S(O)2, and Si(R). C )2, P(R P ), N(R N ), -N=C(R C )2, -Ge(R C )2-, or -Si(R C )- are listed, and each R C , each R N , and each RP is non-substitutable (C1~C 18 ) Hydrocarbyl or -H. The term "heterohydrocarbon" refers to a molecule or molecular skeleton in which one or more carbon atoms are replaced by heteroatoms. (C1~C 40 The term "heterohydrocarbyl" refers to a heterohydrocarbon radical consisting of 1 to 40 carbon atoms. 40 The term "heterohydrocarbile" refers to a heterohydrocarbon diradical having 1 to 40 carbon atoms, where each heterohydrocarbon has one or more heteroatoms. Heterohydrocarbile radicals reside on carbon atoms or heteroatoms, and heterohydrocarbile diradicals may reside on (1) one or two carbon atoms, (2) one or two heteroatoms, or (3) one carbon atom and one heteroatom. Each (C1~C 50 )heterohydrocarbyl and (C1~C 50 ) Heterohydrocarbylene is unsubstituted or (one or more R S It can be substituted by, but may be aromatic or non-aromatic, saturated or unsaturated, linear or branched, cyclic (including monocyclic and polycyclic, condensed and non-condensed polycyclic) or acyclic.

[0046] (C1~C 40 ) Heterohydrocarbyls are either unsubstituted or substituted (C1~C 40 ) Heteroalkyl, (C1~C 40 ) Hydrocarbyl-O-, (C1~C 40 ) Hydrocarbyl-S-, (C1~C 40 ) Hydrocarbyl-S(O)-, (C1~C 40 )hydrocarbyl-S(O)2-, (C1~C 40 ) Hydrocarbyl-Si(R C )2-, (C1~C 40 ) Hydrocarbyl-N(R N )-, (C1~C 40 ) Hydrocarbil-P(R P )-, (C2~C 40 ) Heterocycloalkyl, (C2~C 19 ) Heterocycloalkyl-(C1~C 20 ) Alkilen, (C3~C20 )Cycloalkyl-(C1~C 19 ) Heteroalkylene, (C2~C 19 ) Heterocycloalkyl-(C1~C 20 ) Heteroalkylene, (C1~C 40 ) Heteroaryl, (C1~C 19 ) Heteroaryl-(C1~C 20 ) Alkilen, (C6~C 20 )Aaryl-(C1~C 19 ) Heteroalkylene, or (C1~C 19 ) Heteroaryl-(C1~C 20 ) It may be a heteroalkylene.

[0047] (C4~C 40 The term "heteroaryl" refers to a compound with 4 to 40 total carbon atoms and 1 to 10 heteroatoms, either unsubstituted or substituted (one or more R) atoms. S (by) means monocyclic, bicyclic, or tricyclic heteroaromatic hydrocarbon radicals, where a monocyclic, bicyclic, or tricyclic radical contains 1, 2, or 3 rings, respectively, where 2 or 3 rings are independently condensed or uncondensed, and at least one of the 2 or 3 rings is heteroaromatic. Other heteroaryl groups (e.g., (C4~C) 12 ) such as heteroaryls (C x ~C y Heteroaryl compounds (in general) have x to y carbon atoms (such as 4 to 12 carbon atoms) and are either unsubstituted or have one or two or more R atoms. SIt is defined in a similar manner as being substituted by . Monocyclic heteroaromatic hydrocarbon radicals are five-membered or six-membered rings. A five-membered ring has 5 minus h carbon atoms, where h is the number of heteroatoms, which may be 1, 2, or 3, and each heteroatom may be O, S, N, or P. Examples of five-membered heteroaromatic hydrocarbon radicals include pyrrole-1-yl, pyrrole-2-yl, furan-3-yl, thiophen-2-yl, pyrazole-1-yl, isoxazole-2-yl, isothiazol-5-yl, imidazole-2-yl, oxazole-4-yl, thiazol-2-yl, 1,2,4-triazole-1-yl, 1,3,4-oxadiazole-2-yl, 1,3,4-thiadiazole-2-yl, tetrazole-1-yl, tetrazole-2-yl, and tetrazole-5-yl. A six-membered ring has 6 minus h carbon atoms, where h is the number of heteroatoms, which may be 1 or 2, and the heteroatoms may be N or P. Examples of six-membered ring heteroaromatic hydrocarbon radicals include pyridine-2-yl, pyrimidine-2-yl, and pyrazine-2-yl. Bicyclic heteroaromatic hydrocarbon radicals may be condensed 5,6- or 6,6-ring systems. Examples of condensed 5,6-ring bicyclic heteroaromatic hydrocarbon radicals are indole-1-yl and benzimidazole-1-yl. Examples of condensed 6,6-ring bicyclic heteroaromatic hydrocarbon radicals are quinoline-2-yl and isoquinoline-1-yl. Tricyclic heteroaromatic hydrocarbon radicals may be condensed 5,6,5-, 5,6,6-, 6,5,6-, or 6,6,6-ring systems. An example of a condensed 5,6,5-ring system is 1,7-dihydropyrrolo[3,2-f]indole-1-yl. An example of a condensed 5,6,6-ring system is 1H-benzo[f]indole-1-yl. An example of a condensed 6,5,6-ring system is 9H-carbazole-9-yl. An example of a condensed 6,5,6-ring system is 9H-carbazole-9-yl. An example of a condensed 6,6,6-ring system is acridine-9-yl.

[0048] The aforementioned heteroalkyls are (C1~C 50A heteroalkylene may be a saturated linear or branched radical containing 1 to 50 carbon atoms and one or more heteroatoms. Similarly, a heteroalkylene may be a saturated linear or branched diradical containing 1 to 50 carbon atoms and one or more heteroatoms. Heteroatoms as defined above include Si(R C )3, Ge(R C )3, Si(R C )2, Ge(R C )2, P(R P )2, P(R P ), N(R N )2, N(R N ), N, O, OR C S, SR C It may also contain S(O) and S(O)2, and each of the heteroalkyl group and heteroalkylene group is unsubstituted or has one or more R S It is replaced by.

[0049] Unsubstituted (C2~C 40 Examples of heterocycloalkyls include unsubstituted (C2~C 20 ) Heterocycloalkyl, unsubstituted (C2~C 10 These include heterocycloalkyl compounds, aziridin-1-yl, oxetan-2-yl, tetrahydrofuran-3-yl, pyrrolidine-1-yl, tetrahydrothiophen-S,S-dioxide-2-yl, morpholine-4-yl, 1,4-dioxan-2-yl, hexahydroazepine-4-yl, 3-oxacyclooctyl, 5-thiocyclononyl, and 2-azacyclodecyl.

[0050] The terms "halogen atom" or "halogen" refer to radicals of fluorine (F), chlorine (Cl), bromine (Br), or iodine (I). The term "halogen" refers to fluoride (F) - ), chloride (Cl - ), bromide (Br - ), or iodide (I - This refers to the anionic form of halogen atoms, such as ).

[0051] The term "saturated" means lacking carbon-carbon double bonds, carbon-carbon triple bonds, and (in heteroatom-containing groups) carbon-nitrogen, carbon-phosphorus, and carbon-silicon double bonds. A saturated chemical group has one or more substituents R S If substituted by, one or more double and / or triple bonds may optionally be substituted by substituent R S It may or may not be present. The term "unsaturated" means containing one or more carbon-carbon double bonds, carbon-carbon triple bonds, and carbon-nitrogen, carbon-phosphorus, and carbon-silicon double bonds (in heteroatom-containing groups), provided that substituent R is present if present. S This means that it does not include any double bonds that may or may be present in a (hetero)aromatic ring.

[0052] According to some embodiments, the catalyst system for producing the polyethylene composition comprises a metal-ligand complex according to the following formula (I).

[0053] [ka]

[0054] In formula (I), M is a metal selected from titanium, zirconium, or hafnium, the metal is in a formal oxidation state of +2, +3, or +4, n is 0, 1, or 2, if n is 1, X is a monodentate or bidentate ligand, if n is 2, each X is a monodentate ligand, the same or different, the metal-ligand complex is charge-neutral overall, and each Z is independently -O-, -S-, or -N(R) N )-, or -P(R P )- is selected from, and L is (C1~C 40 ) Hydrocarbylene or (C1~C 40 ) is a heterohydrocarbylene, (C1~C 40 Hydrocarbylene has a portion containing a linker skeleton of 1 to 10 carbon atoms that connects the two Z groups in formula (I) (to which L is bonded), or (C1 to C 40) Heterohydrocarbylene has a portion containing a linker skeleton of 1 to 10 atoms that connects the two Z groups in formula (I), (C1 to C 40 Each of the 1 to 10 atoms in the linker skeleton of heterohydrocarbylene is independently a carbon atom or a heteroatom, and each heteroatom is independently O, S, S(O), S(O)2, Si(R) C )2, Ge(R C )2, P(R C ), or N(R C ) and independently, each R C (C1~C 30 ) Hydrocarbyl or (C1~C 30 ) is a heterohydrocarbyl, R 1 and R 8 These are independently -H, (C1~C 40 ) Hydrocarbyl, (C1~C 40 ) Heterohydrocarbyl, -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 ) Selected from the group consisting of 2NC(O)-, halogens, and radicals having formula (II), formula (III), or formula (IV).

[0055] [ka]

[0056] In equations (II), (III), and (IV), R 31~35 , R 41~48 , or R 51~59 Each of these is independent of (C1~C40 ) Hydrocarbyl, (C1~C 40 ) Heterohydrocarbyl, -Si(R C )3, -Ge(R C )3, -P(R P )2, -N(R N )2, N=CHR C , -OR C , -SR C -NO2, -CN, -CF3, R C S(O)-, R C S(O)2-, (R C )2C=N-, R C C(O)O-, R C OC(O)-, R C C(O)N(R N )-, (R N ) Selected from 2NC(O)-, halogen, or -H, however, R 1 or R 8 The condition is that at least one of them is a radical having formula (II), formula (III), or formula (IV).

[0057] In equation (I), R 2~4 , R 5~7 , and R 9~16 Each of these is independent of (C1~C 40 ) Hydrocarbyl, (C1~C 40 ) Heterohydrocarbyl, -Si(R C )3, -Ge(R C )3, -P(R P )2, -N(R N )2, -N=CHR C , -OR C , -SR C -NO2, -CN, -CF3, R C S(O)-, R C S(O)2-, (R C )2C=N-, R C C(O)O-, R C OC(O)-, R C C(O)N(R N )-, (R C ) Selected from 2NC(O)-, halogen, and -H.

[0058] In some embodiments, the polyethylene composition is formed using a first catalyst according to formula (I) in a first reactor and a different catalyst according to formula (I) in a second reactor.

[0059] In one exemplary embodiment in which a double-loop reactor is used, the pro-catalyst used in the first loop is zirconium,[[2,2' ' '-[[bis[1-methylethyl]germylene]bis(methyleneoxy-κO)]bis[3' ',5,5' '-tris(1,1-dimethylethyl)-5'-octyl[1,1':3',1''-terphenyl]-2'-orato-κO]](2-)]dimethyl-, with chemical formula C 86 H 128 F2GeO4Zr has the following structure (V):

[0060] [ka]

[0061] In such embodiments, the procatalyst used in the second loop is zirconium,[[2,2'''-[1,3-propanediylbis(oxy-κO)]bis[3-[2,7-bis(1,1-dimethylethyl)-9H-carbazole-9-yl]]-5'-(dimethyloctylsilyl)-3'-methyl-5-(1,1,3,3-tetramethylbutyl)[1,1]-biphenyl]-2-orato-κO]](2-)]dimethyl, with chemical formula C 107 H 154 N2O4Si2Zr has the following structure (VI):

[0062] [ka]

[0063] In another embodiment, the procatalyst used in the second loop is hafnium,[[2,2'''-[1,3-propanediylbis(oxy-κO)]bis[3-[2,7-bis(1,1-dimethylethyl)-9H-carbazole-9-yl]]-5'-(dimethyloctylsilyl)-3'-methyl-5-(1,1,3,3-tetramethylbutyl)[1,1]-biphenyl]-2-orato-κO]](2-)]dimethyl, which has the chemical formula C107H154N2O4Si2Zr and the following structure (VII).

[0064] [ka]

[0065] cocatalyst component A catalyst system comprising the metal-ligand complex of formula (I) can be catalytically activated by any technique known in the art for activating metal catalysts in olefin polymerization reactions. For example, a system comprising the metal-ligand complex of formula (I) can be catalytically activated by contacting the complex with an activating co-catalyst or by combining the complex with an activating co-catalyst. Suitable activating co-catalysts for use herein include alkylaluminum, polymers or oligomeric aluminoxanes (also known as aluminoxanes), neutral Lewis acids, and nonpolymers, non-coordinating, ion-forming compounds (including the use of such compounds under oxidizing conditions). A preferred activation technique is bulk electrolysis. Combinations of one or more of the aforementioned activating co-catalysts and techniques are also contemplated. The term "alkylaluminum" means monoalkylaluminum dihydride or monoalkylaluminum dihalide, dialkylaluminum hydride or dialkylaluminum halide, or trialkylaluminum. Examples of polymeric or oligomeric almoxanes include methyl almoxane, triisobutylaluminum-modified methyl almoxane, and isobutyl almoxane.

[0066] Lewis acid activators (co-catalysts) include 1 to 3 (C1 to C) as described herein.20 Examples include group 13 metal compounds containing hydrocarbyl substituents. In one embodiment, the group 13 metal compound is tri((C1~C 20 )hydrocarbyl)-substituted-aluminum or tri((C1~C 20 The (hydrocarbyl)-boron compound is a tri(hydrocarbyl)-substituted aluminum, tri((C1~C 20 (hydrocarbyl)-boron compounds, tri((C1~C 10 )Alkyl) Aluminum, Tri((C6~C 18 These are tris((C1-C))boron compounds and halogenated (including perhalated) derivatives thereof. In further embodiments, the Group 13 metal compounds are tris(fluorosubstituted phenyl)borane and tris(pentafluorophenyl)borane. In some embodiments, the activation co-catalyst is tris((C1-C) 20 ) Hydrocarbyl borate (e.g., trityltetrafluoroborate) or tri((C1~C 20 ) Hydrocarbyl) Ammonium tetra((C1~C 20 (Hydrocarbyl)borane (e.g., bis(octadecyl)methylammoniumtetrakis(pentafluorophenyl)borane). As used herein, the term "ammonium" means ((C1-C 20 ) Hydrocarbyl 4N + , ((C1~C 20 ) Hydrocarbyl 3N(H) + , ((C1~C 20 )hydrocarbyl)2N(H)2 + , (C1~C 20 ) Hydrocarbyl N(H)3 + , or N(H)4 + This refers to nitrogen cations, and each (C1~C 20 If two or more hydrocarbyl molecules are present, they may be the same or different.

[0067] As for combinations of neutral Lewis acid activators (co-catalysts), tri((C1~C4)alkyl)aluminum and halogenated tri((C6~C 18Examples include mixtures containing aryl)boron compounds, particularly combinations with tris(pentafluorophenyl)borane. Other embodiments include combinations of such neutral Lewis acid mixtures with polymer or oligomeric almoxanes, and combinations of a single neutral Lewis acid, particularly tris(pentafluorophenyl)borane, with polymer or oligomeric almoxanes.

[0068] An activated catalyst composition can be formed by activating a catalyst system containing a metal-ligand complex of formula (I) and combining it with one or more co-catalysts, such as a cation-forming co-catalyst, a strong Lewis acid, or a combination thereof. Suitable activating co-catalysts include polymers or oligomers of aluminoxanes, particularly methylaluminoxanes, and inert, miscible, non-coordinating, and ion-forming compounds. Examples of suitable co-catalysts include modified methyl aluminoxane (MMAO), bis(hydrolyzyl hydride), and tetrakis(pentafluorophenyl)borate (1 - Examples include, but are not limited to, amines and combinations thereof.

[0069] In some embodiments, one or more of the aforementioned activated cocatalysts are used in combination with each other. Particularly preferred combinations are mixtures of tri((C1-C4)hydrocarbyl)aluminum, tri((C1-C4)hydrocarbyl)borane, or ammonium borate with an oligomer or polymer of an almoxane compound. The ratio of the total number of moles of one or more metal-ligand complexes of formula (I) to the total number of moles of one or more activated cocatalysts is 1:10,000 to 100:1. In some embodiments, this ratio is at least 1:5000, in some other embodiments it is at least 1:1000 and 10:1 or less, and in some other embodiments it is 1:1 or less. When an almoxane is used alone as an activated cocatalyst, the number of moles of almoxane used is preferably at least 100 times the number of moles of the metal-ligand complex of formula (I). When tris(pentafluorophenyl)borane is used alone as an activation co-catalyst, in some other embodiments, the number of moles of tris(pentafluorophenyl)borane used relative to the total number of moles of one or more metal-ligand complexes of formula (I) is 0.5:1 to 10:1, 1:1 to 6:1, or 1:1 to 5:1. The remaining activation co-catalyst is generally used in a molar amount approximately equal to the total number of moles of one or more metal-ligand complexes of formula (I).

[0070] Cast stretched film Also disclosed is a cast stretched film comprising a polyethylene composition characterized by having the following: (a) 0.910~0.945 g / cm² 3(b) density of 0.5 to 7 g / 10 min melt index (I2), (c) a first polyethylene fraction having a single peak in the temperature range of 40°C to 85°C in the elution profile by improved comonomer composition distribution (iCCD) analysis, (d) a second polyethylene fraction having at least one peak in the temperature range of 90°C to 115°C in the elution profile by iCCD analysis, wherein the second polyethylene area fraction is the area of ​​the elution profile directly below the peak of the second polyethylene fraction in the 90°C to 115°C range, and the second polyethylene area fraction constitutes at least 30% of the total area of ​​the elution profile, and (e) MWCDI value less than 0. In embodiments, the cast-stretched film may be formed from the same or similar polyethylene compositions described above and herein (for example, the polyethylene composition of the cast-stretched film may have the same properties as the polyethylene compositions described above, or not be limited thereto, for example, it may not necessarily have only a “single peak” in the second polyethylene fraction, or it may not necessarily have a width at the 50 percent peak height of the peak of the second polyethylene fraction below 4.0°C).

[0071] Cast-stretched films according to embodiments disclosed herein can be formed by any conventional process known in the art. Generally, cast-stretched films can be formed by a cast film extrusion process, in which a polyethylene composition is melted through a slot or flat die to form a thin molten sheet or film. This film can then be fixed to the surface of a cooling roll (typically water-cooled and chrome-plated) by air blown from an air knife or vacuum box. The film is rapidly quenched and may have slits at the ends before being wound up. The film can be cold-stretched longitudinally and / or transversely without heat and can maintain tension for a long period of time when stretched around a load.

[0072] In some embodiments, the cast-stretched film is a single-layer film. In other embodiments, the cast-stretched film is a multilayer film. In some embodiments of the multilayer film comprising the polyethylene composition of the Disclosure, the multilayer film may also contain the polyethylene composition of the Disclosure in the inner and / or surface layers. The amount of polyethylene composition used in the cast-stretched film of this embodiment may depend on several factors, including, for example, whether the film is a single-layer film or a multilayer film, other layers in the film if it is a multilayer film, and the end use of the film.

[0073] The cast-stretched films of this disclosure may have a variety of thicknesses. The thickness of the cast-stretched film may depend on several factors, including, for example, whether the film is a single-layer film or a multilayer film, and if it is a multilayer film, other layers in the film, the desired properties of the film, the end use of the film, and the equipment available for manufacturing the film. In some embodiments, the cast-stretched films of this disclosure have a maximum thickness of 10 mils. For example, the cast-stretched films may have a minimum thickness of 0.2 mils, 0.5 mils, 0.7 mils, 1.0 mils, 1.75 mils, or 2.0 mils to a maximum thickness of 4.0 mils, 6.0 mils, 8.0 mils, or 10 mils.

[0074] In embodiments where the cast-stretched film is a multilayer film, the number of layers in the film may depend on several factors, including, for example, the desired properties of the film, the desired thickness of the film, the content of other layers in the film, the end use of the film, and the equipment available for manufacturing the film. In various embodiments, the cast-stretched film may contain up to 2, 3, 4, 5, 6, 7, 8, 9, 10, or 11 layers.

[0075] In embodiments where the cast-stretched film is a multilayer film, the cast-stretched film may include other layers such as a surface layer, an adhesion layer, and / or a release layer. For example, the cast-stretched film according to the embodiments disclosed herein may further include, depending on the application, other layers typically found in a cast-stretched film structure, such as other surface layers, adhesion layers, release layers, barrier layers, sealant layers, tie layers, polyethylene layers, and / or polypropylene layers. In further embodiments, a printing layer, which may be an ink layer for displaying product details and other packaging information in various colors, may be included.

[0076] The polyethylene compositions of this disclosure may be incorporated into cast-stretched films and articles, which are substantially or not entirely but primarily made of polyethylene, according to several embodiments, in order to provide films and articles that are more easily recyclable. For example, a cast-stretched film, in which the film is primarily made of polyethylene, has an improved recyclability profile in addition to other advantages that the use of such polymers may provide. In some embodiments, the cast-stretched film contains 95% by weight or more of polyethylene, based on the total weight of the film. In other embodiments, the film contains 96% by weight or more, 97% by weight or more, 98% by weight or more, or 99% by weight or more of polyethylene, based on the total weight of the film. In further embodiments, the cast-stretched film does not contain polypropylene.

[0077] Here, exemplary properties of cast-stretched films containing polyethylene compositions produced according to embodiments disclosed and described herein are provided. The molecular composition of the polyethylene composition may affect the properties of the cast-stretched film. The properties of the cast films disclosed herein can be arbitrarily combined within the scope of this disclosure. The following film properties were measured on cast-stretched films having a thickness of about 0.6 mil, produced without mixing the polyethylene composition with another polymer as disclosed above.

[0078] In embodiments, a cast-stretched film has an average ultimate stretch in the range of 200% to 500% at 0.6 mil and a film width of 20 inches. All individual values ​​and partial ranges of 200% to 500% are disclosed and included herein. For example, a cast-stretched film may have an average ultimate stretch of 200% to 500%, 200% to 475%, 200% to 450%, 250% to 500%, 250% to 475%, 250% to 450%, 300% to 500%, 300% to 475%, 300% to 450%, 325% to 500%, 325% to 475%, or 325% to 450%, and the average ultimate stretch can be measured according to the test methods described below.

[0079] In embodiments, a cast stretched film has an average break time of at least 5 seconds at a thickness of 0.6 mils and a film width of 20 inches. All individual values ​​and partial ranges of at least 5 seconds (s) are disclosed and included herein. For example, a cast stretched film may have an average break time (ESTL tear) of at least 5 seconds, at least 6 seconds, at least 7 seconds, at least 8 seconds, at least 9 seconds, or at least 10 seconds, measured at a thickness of 0.6 mils and a film width of 20 inches, or an average break time (ESTL tear) in the range of 5 seconds to 30 seconds, 7 seconds to 30 seconds, 8 seconds to 30 seconds, 9 seconds to 30 seconds, 5 seconds to 25 seconds, 6 seconds to 25 seconds, 7 seconds to 25 seconds, 8 seconds to 25 seconds, 9 seconds to 25 seconds, or 10 seconds to 25 seconds, measured at a thickness of 0.6 mils and a film width of 20 inches. The break time (ESTL tear) may be measured according to the test methods described below.

[0080] In embodiments, a cast-stretched film has an average pallet tear (OPT) of 10.0 to 20.0 pounds, measured at a thickness of 0.6 mils and a film width of 20 inches. All individual values ​​and subranges of 10.0 to 20 pounds are disclosed and included herein. For example, a cast-stretched film may have an average pallet tear (OPT) of 10.0 to 18 pounds, 10.0 to 16 pounds, 10 to 14 pounds, 11 to 20 pounds, 11 to 18 pounds, 11 to 16 pounds, 11 to 14 pounds, 12 to 20 pounds, 12 to 18 pounds, or 12 to 16 pounds, measured at a thickness of 0.6 mils and a film width of 20 inches. Pallet tear (OPT) can be measured according to the test methods described below herein.

[0081] The cast stretched film of the embodiment has an average pallet puncture (OPP) of 10.0 lbs to 15.0 lbs, e.g., 10.5 lbs to 15.0 lbs, 11.0 lbs to 14.0 lbs, 10.5 lbs to 13.0 lbs, 11.0 lbs to 15.0 lbs, 11.0 lbs to 14.0 lbs, or 11.0 lbs to 13.0 lbs, measured at a thickness of 0.6 mils and a film width of 20 inches using a Type A load test. Pallet punctures using a Type A load test can be measured according to the test method described below.

[0082] Test method density Density was measured according to ASTM D792, in grams / cm³. 3 (g / cm 3 It is represented as ).

[0083] Melt Index (I2) The melt index (I2) is measured at 190°C using 2.16 kg according to ASTM D-1238. The value is reported as g / 10 min, corresponding to the grams eluted per 10 minutes.

[0084] Conventional gel permeation chromatography (GPC) The chromatography system consisted of a PolymerChar GPC-IR (Valencia, Spain) high-temperature GPC chromatograph equipped with an internal IR5 infrared detector (IR5). The autosampler's oven compartment was set to 160°C, and the column compartment to 150°C. The columns used were four Agilent "Mixed A" 30 cm, 20 micrometer linear mixed-bed columns. The chromatography solvent used was 1,2,4-trichlorobenzene containing 200 ppm butylated hydroxytoluene (BHT). The solvent source was spurged with nitrogen. The injection volume used was 200 microliters, and the flow rate was 1.0 ml / min.

[0085] Calibration of the GPC column set was performed using at least 20 polystyrene standards with narrow molecular weight distributions ranging from 580 to 8,400,000 g / mol, with the standards placed in six "cocktail" mixtures with at least 10 intervals between individual molecular weights. The standards were purchased from Agilent Technologies. Polystyrene standards were prepared at a concentration of 0.025 g per 50 ml of solvent for molecular weights of 1,000,000 g / mol or greater, and 0.05 g per 50 ml of solvent for molecular weights less than 1,000,000 g / mol. The polystyrene standards were dissolved at 80°C for 30 minutes with gentle stirring. The peak molecular weights of the polystyrene standards were converted to ethylene polymer molecular weights using Equation 5 (as described in Williams and Ward, J. Polym. Sci., Polym. Let., 6, 621 (1968)).

[0086]

number

[0087] A fifth-order polynomial was used to fit the equivalent calibration points of each ethylene-based polymer. A slight adjustment to A (approximately 0.375–0.440) was made using homopolymer polyethylene standards with a molecular weight of 120,000 g / mol to compensate for column resolution and band broadening effects.

[0088] The total plate count of the GPC column set was calculated using decane (prepared at 0.04 g in 50 ml of TCB and dissolved for 20 minutes with gentle stirring). Plate count (Equation 2) and symmetry (Equation 3) were measured using 200 microliter injections according to the following formulas.

[0089]

number

[0090]

number

[0091] The sample was prepared semi-automatically using PolymerChar "Instrument Control" software, with a target weight of 2 mg / ml. The solvent (containing 200 ppm BHT) was added to a pre-spurged nitrogen-filled vial with a septum cap via a PolymerChar high-temperature autosampler. The sample was dissolved at 160°C for 3 hours with "low-speed" shaking.

[0092] M n(GPC) M w(GPC) , and M z(GPC) The calculation is performed using PolymerChar GPCOne™ software, with each equally spaced data acquisition point i(IR i The IR chromatogram obtained by subtracting the baseline, and the ethylene polymer equivalent molecular weight (in g / mol units) obtained from the narrow standard calibration curve of point i from Equation 1. ポリエチレン,i Based on the GPC results using the built-in IR5 detector (measurement channel) of the PolymerChar GPC-IR chromatograph according to equations 3-6, the results were obtained using ).

[0093] Number average molecular weight M n(GPC) , weight average molecular weight M w(GPC) and z average molecular weight M z(GPC) It can be calculated as follows:

[0094]

number

[0095] To monitor deviations over time, a flow rate marker (decane) was introduced into each sample via a micropump controlled by the PolymerChar GPC-IR system. This flow rate marker (FM) was used to linearly correct the pump flow rate (nominal flow rate) for each sample by matching the RV of each decane peak in the sample (RV(FM sample)) with the RV of the decane peak in the narrow standard calibration (RV(FM calibrated)). Subsequently, it was assumed that any change in the decane marker peak over time was related to a linear shift in the flow rate (effective flow rate) throughout the experiment. To facilitate the highest accuracy of RV measurement of the flow rate marker peak, a least-squares fitting routine was used to fit the peaks of the flow rate marker concentration chromatogram to a quadratic equation. The true peak position was then solved using the first derivative of the quadratic equation. After calibrating the system based on the flow rate marker peak, the effective flow rate (with respect to the narrow standard calibration) was calculated as shown in Equation 7. The processing of the flow rate marker peak was performed via PolymerChar GPCOne® software. The acceptable flow rate is adjusted so that the effective flow rate is within 0.5% of the nominal flow rate.

[0096]

number

[0097] Improved Comonomer Composition Distribution (iCCD) Analysis Method The improved comonomer content analysis method (iCCD) was developed in 2015 (Cong and Parrott et al., International Publication No. 2017040127(A1)). The iCCD test was performed using a Crystallization Elution Fractionation (CEF) instrument (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 guard column made of stainless steel packed with 20-27 micron glass (MoSCi Corporation, USA), measuring 5 cm or 10 cm (length) × 1 / 4 inch (ID), was placed directly in front of the IR-5 detector in the detector oven. Ortho-dichlorobenzene (ODCB, 99% anhydrous or technical grade) was used. Silica gel 40 (particle size 0.2-0.5 mm, catalog number 10181-3) was obtained from EMD Chemicals (it can be used to dry the ODCB solvent beforehand). The dried silica was packed into three empty HT-GPC columns, and the ODCB was further purified as the eluent. The CEF instrument is equipped with an autosampler with N2 purging capability. Before use, the ODCB was spurged with dry nitrogen (N2) for 1 hour. Sample preparation was performed using the autosampler at 4 mg / mL (unless otherwise specified) with shaking at 160°C for 1 hour. The injection volume was 300 μL. The iCCD temperature profile was crystallization from 105°C to 30°C at 3°C / min, thermal equilibrium at 30°C for 2 minutes (including setting the soluble fraction elution time to 2 minutes), and elution from 30°C to 140°C at 3°C / min. The flow rate during crystallization was 0.0 mL / min. The flow rate during elution was 0.50 mL / min. Data is collected at a rate of 1 data point per second.

[0098] The iCCD column was packed with gold-plated nickel particles (Bright 7GNM8-NiS, Nippon Chemical Industrial Co.) in a 15 cm (length) x 1 / 4 inch (ID) stainless steel tube. Column packing and preparation were performed using the slurry method described in the reference (Cong, R.; Parrott, A.; Hollis, C.; Cheatham, M. International Publication No. 2017040127(A1)). The final pressure using TCB slurry packing was 150 bar.

[0099] Column temperature calibration is performed using a linear homopolymer polyethylene (CO2) reference material in the ODCB (comonomer content zero, melt index (I2) 1.0, polydispersity M) w / M n Conventional gel permeation chromatography was performed using a mixture of approximately 2.6 mg / mL (1.0 mg / mL) and eicosane (2 mg / mL). iCCD temperature calibration consisted of the following four steps: (1) calculating the delay volume, which is defined as the temperature offset between the measured peak elution temperatures of eicosane minus 30.00°C; and (2) subtracting 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 and elution flow rate. (3) A step of creating a linear calibration curve that converts the elution temperature over the range of 30.00°C to 140.00°C such that the linear homopolymer polyethylene reference material has a peak temperature of 101.0°C and eicosane has a peak temperature of 30.0°C. (4) A step of linearly extrapolating the elution temperature below 30.0°C for the soluble fraction measured isothermally at 30°C by using an elution heating rate of 3°C / min in accordance with the reference (Cerk and Cong et al., U.S. Patent No. 9,688,795).

[0100] The comonomer content versus iCCD elution temperature was constructed using 12 reference materials (ethylene homopolymers and ethylene-octene random copolymers prepared with single-site metallocene catalysts, with ethylene equivalent weight-average molecular weights ranging from 35,000 to 128,000). All of these reference materials were analyzed at 4 mg / mL using the same method as previously specified. The reported elution peak temperature was 0.9842 R 2 In this study, we followed the graph of mol% octene against iCCD elution temperature (Graph 1).

[0101] [Table 1]

[0102] The molecular weights of the polymer and the polymer fraction were determined directly from an LS detector (90-degree angle) and a concentration detector (IR-5) according to the Rayleigh-Gans-Debys approximation (Striegel and Yau, "Modern Size Exclusion Liquid Chromatogram," pp. 242 and 263), by assuming a form factor of 1 and zero virial coefficients. 23.0~120 Set an integration window to integrate all chromatograms at elution temperatures within the range of °C (temperature calibration specified above).

[0103] Calculating the molecular weight (Mw) from an iCCD involves the following four steps: 1) Measure the inter-detector offset. The offset is defined as the geometric volume offset between the LS detectors relative to the concentration detector. This is calculated as the difference in the elution volume (mL) of the polymer peak between the concentration detector and the LS chromatogram. This is converted to a temperature offset by using the elution thermal rate and elution flow rate. Linear high-density polyethylene (comonomer content zero, melt index (I2) 1.0, polydispersity M w / M n2) Conventional gel permeation chromatography is used, approximately 2.6). The same experimental conditions as the above standard iCCD method are used, except for the following parameters: crystallization from 140°C to 137°C at 10°C / min, thermal equilibrium at 137°C for 1 minute as the soluble fraction elution time, soluble fraction (SF) time of 7 minutes, and elution 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. 2) Each LS data point of the LS chromatogram is shifted to correct for inter-detector offset before integration. 3) The baseline-subtracted LS and concentration chromatograms are integrated over the entire elution temperature range of step 1). The MW detector constant is calculated using HDPE samples with known MW in the range of 100,000 to 140,000 Mw, and the area ratio of the LS to the concentration integrated signal. 4) The Mw of the polymer was calculated using the ratio of the integrated light scattering detector (90-degree angle) and the concentration detector, and the MW detector constant.

[0104] The width at the 50 percent peak height of the second fraction's peak (also known as the full width at half maximum) is calculated for the second elution peak from 35.0°C to 119.0°C using iCCD. The width at the 50 percent peak height of the second fraction's peak is determined by taking half of the peak temperature elution maximum of the second elution peak and calculating the temperature difference between the forward and backward temperatures at half the total height of the second elution peak.

[0105] Molecular Weight Comonomer Distribution Index (MWCDI) The PolymerChar (Valencia, Spain) GPC-IR high-temperature chromatography system included a precision detector (Amherst, MA), a two-angle laser light scattering detector Model 2040, an IR5 infrared detector (GPC-IR), and a four-capacity viscometer (all from PolymerChar). A "15-degree angle" of the light scattering detector was used for calculation purposes. Data acquisition was performed using PolymerChar Instrument Control software and data acquisition interface. The system also included an online solvent degassing device and pump system from Agilent Technologies (Santa Clara, CA).

[0106] The injection temperature was controlled to 150°C. The columns used were four 20-micrometer "PLGel Mixed-A" light scattering columns from Agilent Technologies. The solvent was 1,2,4-trichlorobenzene. The samples were prepared as described in the conventional GPC section of this report. The chromatography solvent and sample preparation solvent each contained "200 ppm butylated hydroxytoluene (BHT)". Both solvent sources were spurged with nitrogen. The ethylene polymer samples were gently stirred at 160°C for 3 hours. The injection volume was "200 microliters" and the flow rate was "1 milliliter / minute".

[0107] Calibration of the GPC column set was performed using 21 polystyrene standards with a "narrow molecular weight distribution" ranging in molecular weight from 580 to 8,400,000 g / mol. These standards were placed in six "cocktail" mixtures with an interval of at least 10 between individual molecular weights. The standards were purchased from Polymer Laboratories (Shropshire, UK). Polystyrene standards were prepared at a rate of "0.025 g in 50 ml of solvent" for molecular weights greater than 1,000,000 g / mol, and at a rate of "0.050 g in 50 ml of solvent" for molecular weights less than 1,000,000 g / mol. The polystyrene standards were dissolved at 80 degrees Celsius for 30 minutes with gentle stirring. The narrow standard mixtures were run first, in an order where the "highest molecular weight component" gradually decreased, to minimize degradation. The peak molecular weight of the polystyrene standard was converted to the polyethylene molecular weight using Equation 8 (as described in Williams and Ward, J. Polym. Sci., Polym. Let., 6, 621 (1968)). M polyethylene = A × (M polystyrene) B (Equation 8), In the formula, M is the molecular weight, A has a value of approximately 0.4315, and B is equal to 1.0. The value of A was adjusted between 0.375 and 0.444 so that the weight-average molecular weight of linear polyethylene corresponds to 120,000 g / mol calculated by the following formula 10 (depending on the specific column set efficiency):

[0108]

number

[0109] In equations 9 and 10, RV is the column-held volume (linearly spaced) collected at "one point per second". IR is the baseline subtracted IR detector signal (in volts) from the measurement channel of the GPC instrument, and LogM PE This is the polyethylene equivalent in MW determined from Equation 8. Data calculations were performed using "GPC One software" from PolymerChar.

[0110] Calibration of the IR5 detector quantification is performed using known short-chain branching (SCB) frequencies in the range of homopolymers (0 SCB / 1000 total carbon atoms) to approximately 50 SCB / 1000 total carbon atoms (where total carbon atoms = carbon atoms in the main chain + carbon atoms in the branches). 13 The study was conducted using at least 10 ethylene-based polymer standards (polyethylene homopolymers and ethylene / octen copolymers) measured by 13C NMR. Each standard had a weight-average molecular weight ranging from 36,000 g / mol to 126,000 g / mol, as determined by the GPC-LALS treatment method described above. Each standard had a molecular weight distribution (Mw / Mn) ranging from 2.0 to 2.5, as determined by the GPC-LALS treatment method described above.

[0111] "IR5 region ratio (or "IR5") of "Baseline subtraction region response of IR5 methyl channel sensor" to "Baseline subtraction region response of IR5 measurement channel sensor" メチルチャネル領域 / IR5 測定チャネル領域 The "SCB" standard was calculated for each of the "SCB" standards (standard filters and filter wheels supplied by PolymerChar: Part Number IR5_FWM01, which was included as part of the GPC-IR instrument). A linear approximation of the SCB frequency versus the "IR5 area ratio" was constructed in the form of Equation 11 below. SCB / Total carbon number 1000 = A0 + [A1 × (IR5 メチルチャネル面積 / IR5 測定チャネル面積 )](Equation 11), where A0 is the intercept of "SCB / total carbon number 1000" at zero "IR5 area ratio", and A1 is the slope of "SCB / total carbon number 1000" versus "IR5 area ratio", representing the increase of "SCB / total carbon number 1000" as a function of "IR5 area ratio".

[0112] A series of "linear baseline subtractive chromatogram heights" from chromatograms generated by the "IR5 methyl channel sensor" were established as a function of column elution volume to generate a baseline-corrected chromatogram (methyl channel). A series of "linear baseline subtractive chromatogram heights" from chromatograms generated by the "IR5 measurement channel" were established as a function of column elution volume to generate a baseline-corrected chromatogram (measurement channel).

[0113] The "IR5 height ratio" of the "baseline-corrected chromatogram (methyl channel)" to the "baseline-corrected chromatogram (measurement channel)" was calculated across the sample integration boundary using the column elution volume index (each equally spaced index representing 1 data point per second with elution of 1 mL / min). The "IR5 height ratio" was multiplied by coefficient A1, and coefficient A0 was added to this result to generate the predicted SCB frequency for the sample. The results were converted to mole percent comonomers as shown in Equation 12 below. Mole percent comonomer = {SCB f / [SCB f +((1000-SCB f * (length of comonomer) / 2) * 100 (Equation 12), where “SCB f " is the "SBC per 1000 total carbon atoms" and the "length of the comonomer" = 8 for octene, 6 for hexene, etc.

[0114] Using the Williams and Ward method (EQ8, as described above), each elution volume index is converted to the molecular weight (Mw i Converted to ). "Mole percent comonomer (y axis)" is Log(Mw i The plot is shown as a function of ), and the slope is Mw for 50,000 g / mol i ~750,000g / mol Mw i The calculation was performed using (corrections for terminal groups relative to the chain ends were omitted for this calculation). Using Excel linear regression, Mw was calculated for the range of 50,000 to 750,000 g / mol (including boundary values). iThe slope was calculated. This slope is defined as the Molecular Weighted Comonomer Distribution Index (MWCDI).

[0115] Typical measurements of the MWCDI of a composition are provided in U.S. Patent No. 1,0138362 (B2), which is incorporated herein by reference in its entirety.

[0116] Zero-shear viscosity ratio (ZSVR) ZSVR is defined as the ratio of the zero shear viscosity (ZSV) of a branched polyethylene material to the ZSV of a linear polyethylene material at the equivalent weight-average molecular weight (Mw-gpc), according to the following equations 13 and 14.

[0117]

number

[0118]

number

[0119] The ZSV value was obtained from a creep test at 190°C using the method described above. The Mw-gpc value was determined by the conventional GPC method (Equation 5 in the explanation of the conventional GPC method). The correlation between the ZSV of linear polyethylene and its Mw-gpc was established based on a series of linear polyethylene reference materials. An explanation of the ZSV-Mw relationship can be found in the ANTEC abstract: Karjala, Teresa P., Sammler, Robert L., Mangnus, Marc A., Hazlitt, Lonnie G., Johnson, Mark S., Hagen, Charles M.Jr., Huang, Joe WL, Reichek, Kenneth N., "Detection of low levels of long-chain branching in polyolefins", Annual Technical Conference-Society of Plastics Engineers (2008), 66th, 887-891.

[0120] Stretched film test The stretching technology is characterized by the use of application-specific tests to predict field performance. A key component of the application tests is testing the film in a stretched state, thereby simulating its performance during stretched wrapping. For all film tests, samples with a thickness of 0.6 mil and a film width of 20 inches are tested. Two types of stretch tests are performed on the produced films in the stretching laboratory. One involves the use of an ESTL film performance tester, which was developed to provide stretched film tests under representative conditions. The ESTL film performance tester is used to measure the ultimate stretch, which represents the maximum level of stretch that can be applied during pallet wrapping. The tester is also used to perform tear propagation tests to analyze the tear performance of the stretched film.

[0121] The second test set simulates pallet wrapping using a Lantech stretch wrapper with a 44-inch x 35-inch x 60-inch metal frame housed within a housing. Tests conducted in this setup capture the film's mechanical or abuse properties, as well as its ability to unitize loads and its adhesion values.

[0122] Extreme stretching (US) The ultimate stretch is measured using an ESTL (ESTL, Deerlijk, Belgium)-FPT-750 Film Property Tester. The ultimate stretch test is selected from the test menu, and then the W-wrap method is selected. Table A shows the instrument settings used in this method. Unwinding force, winding force, peeling force, stretching force, peeling angle, and noise level are measured as a function of pre-stretch. The pre-stretch is increased up to the breaking point. The winding speed during the test is kept constant at 360 feet / min. The test is repeated three times, and the average ultimate stretch (US) is reported as a percentage of the ultimate stretch (%).

[0123] [Table 2]

[0124] Pallet-mounted puncture - Type A loading (OPP-A) This test uses the Bruceton staircase method to determine the maximum load force that a film can pass over a test probe for three wraps without breaking. Insert the test probe into the test stand at the desired protrusion distance. Type A loads are tested with a 3-inch probe. Type B loads are tested with a 6-inch probe, and Type C loads are tested with a 12-inch probe. Position the film so that the test probe aligns with the center of the film. Mount the film on the test stand and start the wrapper. When the wrapper reaches a preliminary stretch of 250%, the film is able to pass over the probe for up to three wraps. Wrap the film three times, starting with a low F2 force of 7 pounds. If the film is not punctured by the probe, repeat the test with an F2 force increased in 0.5-pound increments until it breaks. After every 0.5-pound increment, manually press the film against the probe and test a new set of film. If the film breaks during any of the wraps, the load setting at that force is considered a failure. Depending on the film's performance (i.e., pass-through or breakage) at the load setting, the load force is adjusted up or down, and the test is repeated with the new load setting. This test is continued until the maximum force at which breakage exceeds 50% is found. The F2 force at which breakage occurs represents the puncture value of the film on the pallet, and generally, the standard deviation is not reported unless the test is repeated more than twice, starting at 7 pounds. The significance of the data is considered to be + / - 1 pound, and the highest pass-through F2 force is reported. Type A load testing is commonly used in pallet packing, and those skilled in the art should understand that its meaning is recognized when used herein. Table B shows the equipment and settings used in this method.

[0125] [Table 3]

[0126] Pallet-mounted puncture - Type B loading (OPP-B) When a unitized pallet is not uniform in shape and exhibits limited irregularity, it is defined as a Type "B-load". This test uses the Bruceton staircase method to determine the maximum load force that the film can pass over the test probe for three wraps without breaking. The test probe is inserted into the test stand at the desired protrusion distance. All films were tested with a 2-inch x 2-inch blunt metal probe extending 6 inches outward. The film is positioned so that the test probe aligns with the center of the film. The film is mounted on the test stand and the wrapper is initiated. When the wrapper reaches a pre-stretch of 250%, the film is able to pass over the probe for up to three wraps. The film is wrapped three times, starting at a post-stretch film tension / load force (F2) of 7 pounds. If the film is not punctured by the probe, the test is repeated with an F2 force increasing in 0.5-pound increments until it breaks. If the film breaks during any of the wraps, the load setting at that force is considered a failure. The test is repeated six times at a single force setting once the F2 force reaches the point where breakage begins. If the film passes four out of the six tests, the F2 force of the film is increased. If the film breaks four out of the six tests, the test is stopped, and this is considered the point of breakage of the film. Depending on the performance of the film at each load setting (i.e., pass or break), the load force is increased / decreased, and the test is repeated with a new load setting. This test is continued until a maximum force is found at which breakage exceeds 50%. The highest passing F2 force is reported as the pallet pinch (OPP) value. A typical variation in this test is observed to be + / - 1 pound. The Type B load test is commonly used in pallet packing, and those skilled in the art should understand that its meaning is recognized when used herein. Table C below shows the equipment and settings used in this method.

[0127] [Table 4]

[0128] Tearing on pallet (OPT) This test uses the Bruseton step method to determine the maximum load force that a film can withstand before passing through a test probe fixed to a blade to initiate a puncture. The test probe is inserted into the test stand at the desired protrusion distance. The film is positioned so that the test probe aligns with the center of the film. The film is mounted on the test stand and the wrapper is started. When the wrapper reaches a preliminary stretch of 250%, the film is passed through the probe, and a single layer of film is tested in this test. The film tension (F2 force) is increased in 0.5-pound increments from an initial low value of approximately 7 pounds until the film is completely torn in the cross direction (CD) or transverse direction (TD). The tear value on the pallet is recorded as the maximum F2 force at which the initial puncture propagates across the entire width of the film and does not result in breakage. Table D shows the equipment and settings used in this method.

[0129] [Table 5]

[0130] Tear propagation / break time (ESTL tear) Tear propagation / break time is measured using the ESTL Film Property Tester (ESTL, Deerlijk, Belgium) - FPT-750 Film Property Tester. Select "Tear Propagation" from the test menu, then select the W-wrap method. Table E shows the parameters selected by the instrument to measure the break time (ESTL tear). A cast stretched film sample is pre-stretched, and then the film is clamped. A small "spear-shaped knife" is used to create a small vertical cut in the film. After this cut is made, the canvas releases the clamp on the film. After 1 second, the winding spindle begins to pull the film at a constant speed. The other shafts are blocked. This creates tensile force on the film after the initial cut. The FPT-750 Film Property Tester monitors the time and force required to cut through the entire height of the film. The test is repeated three times, and the average break time is reported in seconds (s).

[0131] [Table 6] [Examples]

[0132] Preparation of polyethylene compositions of the present invention (Poly.1 and Poly.2) The polyethylene compositions of the present invention ("Poly.1" and "Poly.2") are prepared according to the following process and table.

[0133] Before introducing them into the reaction environment, all raw materials (monomers and comonomers) and process solvent (high-purity isoparaffinic solvent with a narrow boiling point range, Isopar-E) are purified using molecular sieves. High-purity hydrogen is supplied via a shared pipeline and dried using molecular sieves. The monomer feed stream to the reactor is pressurized to a pressure higher than the reaction pressure by a mechanical compressor. The solvent feed is pressurized to a pressure higher than the reaction pressure by a pump. The comonomer feed is pressurized via a pump until it exceeds the reaction pressure. Individual catalyst components are manually batch-diluted with the purified solvent and pressurized to exceed the reaction pressure. All reaction feed streams are measured using mass flowmeters and independently controlled by computer-automated metering pumps.

[0134] The reactor configuration is either a double parallel reactor operation or a double series reactor operation, as specified in Table G.

[0135] Either a single reactor system, two reactor systems in parallel, or two reactor systems in series is used. Each reactor is a continuous solution polymerization reactor consisting of a liquid-filled, adiabatic, continuously stirred tank reactor (CSTR). All fresh solvent, monomers, comonomers (if present), hydrogen, and catalyst component feeds can be independently controlled. The entire fresh feed stream to each reactor (solvent, monomer, comonomers [if present], and hydrogen) is temperature-controlled, typically between 15 and 50°C, to maintain a single solution phase by passing the feed stream through a heat exchanger. All fresh feeds to each polymerization reactor are injected into the reactor at a single point. The fresh feed is controlled so that each injector receives half of the total fresh feed flow rate. Catalyst components are injected into the polymerization reactor separately from the other feeds. The supply of the primary catalyst component is computer-controlled to maintain reactor monomer conversion at a specific value. Co-catalyst components (one or more) are supplied to the primary catalyst component based on a calculated specific molar ratio. The agitator in the reactor is responsible for the continuous mixing of the reactants. The oil bath provides some fine-tuning of the reactor temperature control.

[0136] In a dual parallel reactor configuration, the effluent flows from the first and second polymerization reactors are aligned before any additional processing.

[0137] In a double series reactor configuration, the effluent from the first polymerization reactor (containing solvent, monomer, comonomer [if present], hydrogen, catalyst components, and polymer) flows out of the first reactor loop and is added to the second reactor separately from other feeds to the second reactor.

[0138] In all reactor configurations, the final reactor effluent (second reactor effluent in the case of a double series configuration, combined effluent in the case of a double parallel configuration, or single reactor effluent) enters a zone where it is deactivated by the addition and reaction with a suitable reagent (usually water). At this same reactor outlet location, other additives are added for polymer stabilization (typical antioxidants suitable for stabilization during extrusion and fabrication, such as octadecyl 3,5-di-Tert-butyl-4-hydroxyhydrocinnamate, tetrakis(methylene(3,5-di-Tert-butyl-4-hydroxyhydrocinnamate))methane, and tris(2,4-di-Tert-butyl-phenyl)phosphite, as well as acid scavengers such as calcium stearate as needed).

[0139] Following catalyst deactivation and additive addition, the reactor effluent enters a devolving system where the polymer is removed from the non-polymer stream. The isolated polymer molten material is pelletized and recovered. The non-polymer stream is removed from the system.

[0140] Figures 2 and 3 schematically show the reactor flow feed data flow corresponding to the values ​​and information in Tables F and G used to produce polyethylene compositions (Poly.1 and Poly.2).

[0141] [Table 7]

[0142] [Table 8]

[0143] Commercial polyethylene compositions Poly.3 is INNATE® XUS.59910.08, a linear low-density polyethylene composition commercially available from The Dow Chemical Company (Midland, MI).

[0144] Poly.4 is DOWLEX™ 2045, a linear low density polyethylene composition commercially available from The Dow Chemical Company (Midland, MI).

[0145] Poly.5 is INNATE™ ST50, a polyethylene composition commercially available from The Dow Chemical Company (Midland, MI).

[0146] Preparation of Developed Polyethylene Compositions (Poly.6, Poly.7, Poly.8, and Poly.9) Developed polyethylene compositions (“Poly.6”, “Poly.7”, “Poly.8”, and “Poly.9”) are prepared according to the following process and table.

[0147] Before introducing into the reaction environment, all raw materials (monomers and comonomers) and the process solvent (a high purity isoparaffin solvent with a narrow boiling range, Isopar-E) are purified with molecular sieves. High purity hydrogen is supplied by a common pipeline and dried with a molecular sieve. The monomer feed stream to the reactor is pressurized by a mechanical compressor to a pressure higher than the reaction pressure. The solvent feed is pressurized by a pump to a pressure higher than the reaction pressure. The comonomer feed is pressurized via a pump until it exceeds the reaction pressure. Each catalyst component is manually batch diluted with the purified solvent and pressurized until it exceeds the reaction pressure. All reaction feed streams are measured using mass flow meters and independently controlled by an automated metering pump by a computer.

[0148] Two reactor systems are used in a series configuration. Each continuous solution polymerization reactor consists of a liquid-filled, non-adiabatic isothermal circulating loop reactor that replicates a continuous stirred tank reactor (CSTR) for heat removal. All fresh solvent, monomer, comonomer (if present), hydrogen, and catalyst component feeds are independently controlled. The entire fresh feed stream to each reactor (solvent, monomer, comonomer [if present], and hydrogen) is temperature-controlled, typically between 15 and 50°C, to maintain a single solution phase by passing the feed stream through a heat exchanger. The entire fresh feed to each polymerization reactor is injected into the reactor at two locations, with approximately equal reactor volumes between each injection point. The fresh feed is controlled so that each injector accepts half of the total fresh feed flow rate. Catalyst components are injected into the polymerization reactor through specially designed injection needles. The supply of the primary catalyst component is computer-controlled to maintain reactor monomer conversion at a specific value. Co-catalyst components (one or more) are supplied to the primary catalyst component based on a calculated specific molar ratio. Immediately after the injection point of each reactor feed, the feed stream is mixed with the contents of a circulating polymerization reactor having a static mixing element. The contents of each reactor are passed through a heat exchanger, which plays a role in removing most of the reaction heat, and the coolant side temperature plays a role in maintaining an isothermal reaction environment at a specific temperature, and the reactor is continuously circulated. Circulation around each reactor loop is provided by a pump.

[0149] The effluent from the first polymerization reactor (containing solvent, monomer, comonomer [if present], hydrogen, catalyst components, and polymer) flows out of the first reactor loop and is added to the second reactor separately from other feeds to the second reactor.

[0150] The final reactor effluent (the effluent of the second reactor in the case of a double series configuration) enters a zone where it is deactivated by the addition of a suitable reagent (water) and reaction. At the outlet of this same reactor, other additives are added for polymer stabilization (typical antioxidants suitable for stabilization during extrusion and fabrication such as octadecyl 3,5 - di - tert - butyl - 4 - hydroxyhydrocinnamate, tetrakis(methylene(3,5 - di - tert - butyl - 4 - hydroxyhydrocinnamate))methane, and tris(2,4 - di - tert - butyl - phenyl)phosphite, and optionally an acid scavenger such as calcium stearate).

[0151] Following catalyst deactivation and additive addition, the reactor effluent enters a devolatilization system where the polymer is removed from the non - polymer stream. The isolated polymer melt is pelletized and recovered. The non - polymer stream passes through various equipment that separates most of the ethylene removed from the system. Most of the solvent and unreacted comonomer are recycled to the reactor after passing through a purification system. A small amount of solvent and comonomer is purged from the process.

[0152] The reactor stream feed data flow corresponding to the values and information in Tables H and I is used to produce polyethylene compositions (Poly.6, Poly.7, Poly.8, and Poly.9) and is schematically shown in Figure 3. The data is presented with the complexity of the solvent recycle system considered and the reaction system presented in a more easily processed form as a flow - through flow diagram.

[0153]

Table 9

[0154]

Table 10

[0155] Analysis of Polyethylene Samples Poly.1 to Poly.9 were analyzed by iCCD and GPC. The density, melt index (I2), MWCDI, and zero shear viscosity ratio (ZSVR) of the compositions were also measured. The data obtained from the analysis and testing are reported in Tables 1 and 1A. As an example, the iCCD elution profile and GPC overlay of Poly.1 are shown in Figures 4 and 5, respectively.

[0156] [Table 11] * Not measured (NM)

[0157] [Table 12] * Not measured (NM)

[0158] Three-ply and five-ply cast stretched films are manufactured on a five-ply Egan Davis Standard co-extrusion cast film line. The cast line consists of three air-cooled 2-1 / 2-inch and two 2-inch 30:1 L / D Egan Davis Standard MAC extruders. All extruders have DSB (Davis Standard Barrier) type screws for moderate operation. A microprocessor monitors and controls the operation. The extrusion process is monitored by pressure transducers located before and after the breaker plate, as well as four heating zones on each barrel, one each on the adapter and block, and two zones on the die. The microprocessor also tracks the extruder's RPM, %FLA, HP, rate, line speed, stretch %, primary and secondary cooling roll temperatures, gauge deviation, layer ratio, rate / RPM, and the melting temperature of each extruder.

[0159] The machine specifications include a Cloeren 5-layer dual-plane feed block and a Cloeren 36-inch Epoch III automatic gauge 5.1 die. The primary cooling roll is mirror-finished, 40 inches in outer diameter x 40 inches in length, and has a surface finish of 30 - 40 RMS for improved peel characteristics. The secondary cooling roll is 20 inches in outer diameter x 40 inches in length and has a surface of 2 - 4 RMS for improved web tracking. Cooling water circulates through both the primary and secondary cooling rolls for rapid cooling. There is an X-ray gauge sensor from Scantech for gauge thickness and automatic gauge control as required. The speed is measured by five Barron metering hoppers equipped with load cells for each hopper for weight control. The sample ends on a 3-inch ID core with a 2-position single turret Horizon winder with a center wind automatic roll changeover and a slitter station. The maximum line throughput speed is 600 pounds per hour and the maximum line speed is 1200 feet per minute.

[0160] The conditions for sample preparation are as shown in Table 2.

[0161]

Table 13

[0162] In addition to Poly.1 - Poly.9, the following materials are also used in the formulation of the films of the present invention and the comparative films.

[0163] DR376_01 ("PP"), a polypropylene commercially available from Braskem (Sao Paulo, Brazil).

[0164] ATTANE (trademark) 4404G, an ultra-low density polyethylene copolymer commercially available from The Dow Chemical Company (Midland, MI).

[0165] ELITE (trademark) 5230G is a modified polyethylene resin commercially available from The Dow Chemical Company (Midland, MI).

[0166] Three-layer and five-layer cast-stretched films are formed and referred to as the film of the present invention and the comparative film. In each three-layer film, ATTANE™ 4404G is used for the outer layer (layer 1), ELITE™ 5230G is used for the other outer layer (layer 3), and PP or Poly.1 to Poly.5 is used for the inner layer (layer 2). Tables 3, 4, and 5 below show the formulations of the three-layer comparative examples and the examples of the present invention. In comparative films 2 to 4 and film 1 of the present invention, PP or Poly.3 to 5 constitute 20% of the total film composition.

[0167] [Table 14]

[0168] [Table 15]

[0169] [Table 16]

[0170] In each 5-layer film, ATTANE® 4404G is used for the outer layer (layer 1), ELITE® 5230G is used for the other outer layer (layer 5) and the core layer (layer 3), and Poly.1 to Poly.9 are used for the sub-inner layers (layers 2 and 4). Tables 6, 7, and 7A below show the formulations of the 5-layer comparative examples and the examples of the present invention. In comparative films 5 to 6 and films 2 to 4 of the present invention, Poly.1 to 9 constitute 30% of the total film formulation (i.e., 15% in layer 2 and 15% in layer 4).

[0171] [Table 17]

[0172] [Table 18]

[0173] [Table 19]

[0174] The properties of the film of the present invention and the comparative films were measured according to the test methods disclosed herein and are shown in Tables 8, 9, and 9A. As can be seen from the results, film 1 of the present invention has remarkably high pallet tear and break time (ESTL tear) compared with comparative films 3 and 4. Similarly, films 2-8 of the present invention have remarkably high pallet tear and break time (ESTL tear) compared with comparative films 5 and 6.

[0175] [Table 20] * Not measured

[0176] [Table 21] * Not measured

[0177] [Table 22] * Not measured

[0178] All documents cited herein, including any cross-referenced or related patents or applications, and any patent applications or patents to which this application claims priority or benefit, are incorporated herein by reference in their entirety unless expressly excluded or otherwise limited. No reference to any document constitutes prior art relating to any invention disclosed or claimed herein, nor does it teach, suggest or disclose such invention, either alone or in any combination with any other reference. Furthermore, if any meaning or definition of a term in this document conflicts with any meaning or definition of the same term in any document incorporated by reference, the meaning or definition assigned to that term in this document shall prevail.

[0179] While specific embodiments of the present invention have been illustrated and described, it will be apparent to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. Therefore, the appended claims are intended to encompass all such changes and modifications that fall within the scope of the invention. The present specification includes the following embodiments. Section 1: A polyethylene composition, (a) 0.910~0.945 g / cm³ 3 The density and (b) Melt index (I2) of 0.5-7.0 g / 10 min, (c) The first polyethylene fraction having a single peak in the temperature range of 40°C to 85°C in the elution profile by improved comonomer composition distribution (iCCD) analysis, (d) A second polyethylene fraction having a single peak in the temperature range of 90°C to 115°C in the elution profile obtained by iCCD analysis, wherein the second polyethylene area fraction is the area of ​​the elution profile directly below the peak of the second polyethylene fraction at 90°C to 115°C, the second polyethylene area fraction constitutes at least 30% of the total area of ​​the elution profile, and the width at the 50 percent peak height of the peak of the second polyethylene fraction is less than 4.0°C, (e) A polyethylene composition characterized by having a molecular weight comonomer distribution index (MWCDI) value of less than 0. Section 2: The polyethylene composition according to item 1, wherein the MWCDI value is less than -3. Section 3: The polyethylene composition according to claim 1 or 2, wherein the second polyethylene fraction has a weight-average molecular weight (Mw) of at least 95,000 g / mol. Section 4: The polyethylene composition according to any one of claims 1 to 3, further characterized in that the polyethylene composition has a molecular weight distribution in the range of 2.0 to 8.0, expressed as the ratio of weight-average molecular weight to number-average molecular weight (Mw / Mn). Section 5: The polyethylene composition according to any one of claims 1 to 4, further characterized in that the polyethylene composition has a zero shear viscosity ratio (ZSVR) of less than 3.0. Item 6: The polyethylene composition according to any one of claims 1 to 5, wherein the first polyethylene fraction of the polyethylene composition is formed in the presence of a first molecular catalyst, and the second polyethylene fraction of the polyethylene composition is formed in the presence of a second molecular catalyst. Section 7: It is a cast stretched film, (a) 0.910~0.945 g / cm³ 3 The density and (b) Melt index (I2) of 0.5-7g / 10 min, (c) The first polyethylene fraction having a single peak in the temperature range of 40°C to 85°C in the elution profile by improved comonomer composition distribution (iCCD) analysis, (d) A second polyethylene fraction having at least one peak in the temperature range of 90°C to 115°C in the elution profile obtained by iCCD analysis, wherein the second polyethylene area fraction is the area of ​​the elution profile directly below the peak of the second polyethylene fraction at 90°C to 115°C, and the second polyethylene area fraction constitutes at least 30% of the total area of ​​the elution profile, (e) A cast stretched film comprising a polyethylene composition characterized by having a MWCDI value of less than 0. Section 8: The cast stretched film according to item 7, wherein the width at the 50 percent peak height of the peak of the second polyethylene fraction is less than 4.0°C. Section 9: The cast-stretched film according to item 7 or 8, wherein the cast-stretched film has a pallet tear of 4535.9237 to 9071.8474 g (10.0 to 20.0 pounds) at a thickness of 15.24 μm (0.6 mil) and a film width of 50.8 cm (20 inches). Section 10: The cast stretched film according to any one of claims 7 to 9, wherein the cast stretched film has an average break time of at least 5 seconds.

Claims

1. A polyethylene composition, (a) 0.910-0.945g / cm ３ The density and (b) Melt index (I) of 0.5-7.0 g / 10 min ２ )and, (c) A first polyethylene fraction having a single peak in the temperature range of 40°C to 85°C in the elution profile by improved comonomer composition distribution (iCCD) analysis, (d) A second polyethylene fraction having a single peak in the temperature range of 90°C to 115°C in the elution profile obtained by iCCD analysis, wherein the second polyethylene area fraction is the area of ​​the elution profile directly below the peak of the second polyethylene fraction in the 90°C to 115°C range, the second polyethylene area fraction constitutes at least 30% of the total area of ​​the elution profile, and the width at the 50 percent peak height of the peak of the second polyethylene fraction is less than 4.0°C, (e) A polyethylene composition characterized by having a molecular weight comonomer distribution index (MWCDI) value of less than 0.

2. The polyethylene composition according to claim 1, wherein the MWCDI value is less than -3.

3. The polyethylene composition according to claim 1 or 2, wherein the second polyethylene fraction has a weight-average molecular weight (Mw) of at least 95,000 g / mol.

4. The polyethylene composition according to any one of claims 1 to 3, further characterized in that the polyethylene composition has a molecular weight distribution in the range of 2.0 to 8.0, expressed as the ratio of weight-average molecular weight to number-average molecular weight (Mw / Mn).

5. The polyethylene composition according to any one of claims 1 to 4, further characterized in that the polyethylene composition has a zero shear viscosity ratio (ZSVR) of less than 3.

0.

6. The polyethylene composition according to any one of claims 1 to 5, wherein the first polyethylene fraction of the polyethylene composition is formed in the presence of a first molecular catalyst, and the second polyethylene fraction of the polyethylene composition is formed in the presence of a second molecular catalyst.

7. It is a cast stretched film, (a) 0.910-0.945g / cm ３ The density and (b) Melt index (I) 0.5-7 g / 10 min ２ )and, (c) A first polyethylene fraction having a single peak in the temperature range of 40°C to 85°C in the elution profile by improved comonomer composition distribution (iCCD) analysis, (d) A second polyethylene fraction having at least one peak in the temperature range of 90°C to 115°C in the elution profile obtained by iCCD analysis, wherein the second polyethylene area fraction is the area of ​​the elution profile directly below the peak of the second polyethylene fraction in the 90°C to 115°C range, and the second polyethylene area fraction constitutes at least 30% of the total area of ​​the elution profile, (e) A cast stretched film comprising a polyethylene composition having an MWCDI value of less than 0.

8. The cast stretched film according to claim 7, wherein the width at the 50 percent peak height of the peak of the second polyethylene fraction is less than 4.0°C.

9. The cast-stretched film according to claim 7 or 8, wherein the cast-stretched film has a pallet tear of 4535.9237 to 9071.8474 g (10.0 to 20.0 pounds) at a thickness of 15.24 μm (0.6 mil) and a film width of 50.8 cm (20 inches).

10. The cast stretched film according to any one of claims 7 to 9, wherein the cast stretched film has an average break time of at least 5 seconds.

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