Multimodal ethylene copolymer composition and process for producing it

Abstract

A process for producing a multimodal ethylene copolymer. This process includes adding ethylene, at least one olefin monomer, at least a first catalyst system, and less than 0.3 mol% hydrogen gas to a solution polymerization reactor to produce an effluent feed at a reactor temperature of 100°C or higher. The effluent feed and the second catalyst system are supplied to a second reactor in the absence of fresh feed and hydrogen gas. At least one of the first and second catalyst systems has a chain transfer constant of 0.005 to 1.0. The multimodal ethylene copolymer contains a high molecular weight fraction (meaning a molecular weight fraction greater than 500,000 g / mol) of 8% to 50% based on the total percentage of the multimodal ethylene copolymer.

Description

[Technical Field]

[0001] (Cross-reference of related applications) This application claims the benefits of U.S. Provisional Application No. 63 / 510,779, filed on 28 June 2023, which is incorporated herein by reference in its entirety.

[0002] Embodiments of this disclosure generally relate to polymer compositions, and more specifically to multimodal ethylene copolymer compositions and processes for producing them. [Background technology]

[0003] The use of polyolefin compositions in industries such as packaging is generally known. Various conventional methods can be used to produce such polyolefin compositions. Various polymerization techniques using different catalyst systems have been employed to produce such polyolefin compositions suitable for packaging applications. However, in some embodiments, despite research efforts in developing compositions suitable for packaging applications, there remains a need for improved polyethylene compositions suitable for packaging applications that can have a good balance between physical properties and melt strength at a desired polymer composition density. [Overview of the Initiative]

[0004] Melt strength and processability are correlated properties of polyethylene resin. Generally, higher melt strength provides polyethylene resin with improved processability.

[0005] In addition, conventional polyethylene resins produced by conventional processes typically exhibit a trade-off between the resin's mechanical properties and melt strength. For example, conventional radical processes, which are known to be hazardous, typically produce low-density polyethylenes (LDPE) that exhibit high melt strength but have insufficient mechanical properties. In contrast, linear low-density polyethylenes (LLDPE), produced via solution or gas-phase processes, typically have insufficient melt strength but excellent mechanical properties.

[0006] Therefore, to increase processability and improve the processability and melt strength of LLDPE resin, some amount of LDPE can typically be blended with LLDPE. Unfortunately, the addition of LDPE results in a decrease in the mechanical properties of the resulting blend compared to pure LLDPE resin.

[0007] Therefore, there is a need for a solution polymerization process that can produce polyethylene resins with melt strength comparable to those produced via radical processes. Specifically, there is a need for a solution polymerization process that can produce polyethylene resins with melt strength comparable to those produced via radical processes. Therefore, in order to produce multimodal ethylene copolymers, it is necessary to produce high molecular weight (HMW) polyethylene copolymers and low molecular weight (LMW) polyethylene copolymers. These multimodal ethylene copolymers having an HMW ethylene copolymer component have higher melt strength than polyethylenes with similar melt index that do not have this HMW polyethylene component.

[0008] Embodiments of this disclosure satisfy these requirements by providing a multimodal ethylene copolymer comprising a bulk low molecular weight (LMW) ethylene component produced by one or more catalysts and a high molecular weight (HMW) ethylene component produced by different or more catalysts. The multimodal ethylene copolymers described herein, together with the HMW ethylene component, may have long-chain branching that enables the achievement of melt strengths comparable to or higher than those of various LDPEs produced by conventional processes. As a result, the multimodal ethylene copolymers described herein can be used as blend components with LLDPE in amounts less than those required for conventional LDPE resins, thereby resulting in improved mechanical properties of the resulting LLDPE blend compared to the mechanical properties of conventional LLDPE / LDPE blends. In embodiments, the multimodal ethylene copolymers are produced by a solution polymerization process.

[0009] Embodiments of this disclosure include processes that utilize the use of low H2 levels. By controlling the level of H2 in the reactor, it may be possible to adjust the molecular weight of the ethylene copolymer. If the H2 level is too high, the molecular weight difference between the polymers produced by the two catalysts may decrease to a point where no HMW ethylene copolymer component is present (and both catalysts would produce LMW PE), and no improvement in melt strength is obtained.

[0010] Embodiments of the present disclosure include a process for producing a multimodal ethylene copolymer. In embodiments, the process includes adding ethylene, at least one olefin monomer, at least a first catalyst system, and less than 0.3 mol% of hydrogen gas to a solution polymerization reactor to produce an effluent feed at a reactor temperature of 150°C or higher, and supplying the effluent feed and a second catalyst system to a second reactor in the absence of fresh feed and hydrogen gas, wherein the first catalyst system comprises a first procatalyst and a first activator, the second catalyst system comprises a second procatalyst and optionally a second activator, and at least one of the first and second catalyst systems has a chain transfer constant of 0.005 to 1.0. The multimodal ethylene copolymer further contains a high molecular weight fraction of 8-50%, based on the total percentage of the multimodal ethylene copolymer, calculated by measuring the area fraction of the molecular weight chromatogram obtained from the absolute molecular weight obtained from low-angle light scattering exceeding 500,000 g / mol. [Modes for carrying out the invention]

[0011] Embodiments of multimodal ethylene copolymer compositions and processes for producing them are described herein. Ethylene-based polymers of ethylene and one or more comonomers, such as α-olefins, may contain at least 50 mole percent (mol%) of monomer units derived from ethylene. All individual values ​​and sub-ranges encompassed by “at least 50 mole percent” are disclosed herein as separate embodiments. For example, an ethylene-based polymer may contain at least 60 mole percent of monomer units derived from ethylene, at least 70 mole percent of monomer units derived from ethylene, at least 80 mole percent of monomer units derived from ethylene, or 50 to 100 mole percent of monomer units derived from ethylene, or 80 to 100 mole percent of monomer units derived from ethylene.

[0012] process Embodiments of the present disclosure include a process for producing a multimodal ethylene copolymer. In embodiments, the process includes adding ethylene, at least one olefin monomer, at least a first catalyst system, and less than 0.3 mol% of hydrogen gas to a solution polymerization reactor to produce an effluent feed at a reactor temperature of 150°C or higher, and supplying the effluent feed and a second catalyst system to a second reactor in the absence of fresh feed and hydrogen gas, wherein the first catalyst system comprises a first procatalyst and a first activator, the second catalyst system comprises a second procatalyst and optionally a second activator, and at least one of the first and second catalyst systems has a chain transfer constant of 0.005 to 1.0. The multimodal ethylene copolymer further contains a high molecular weight fraction of 8-50%, based on the total percentage of the multimodal ethylene copolymer, calculated by measuring the area fraction of the molecular weight chromatogram obtained from the absolute molecular weight obtained from low-angle light scattering exceeding 500,000 g / mol.

[0013] In embodiments, multimodal ethylene copolymer compositions may be produced via a solution polymerization process. In embodiments, the process for producing a multimodal ethylene copolymer may involve contacting at least two olefin monomers in a solution polymerization reactor system in the presence of a catalyst system comprising at least one low molecular weight catalyst and at least one high molecular weight catalyst.

[0014] In embodiments, the solution polymerization reactor system may include one or more reactors. In embodiments, the solution polymerization reactor system may be a single-reactor system. In embodiments, the solution polymerization reactor system may be a double-reactor system. In embodiments including a double-reactor system, the solution polymerization reactor system may include a first reactor and a second reactor. Such a solution polymerization process may involve using, for example, one or more conventional reactors, such as loop reactors, isothermal reactors, adiabatic reactors, fluidized bed gas-phase reactors, stirred-tank reactors (e.g., continuous stirred-tank reactors), and batch reactors, for example, in parallel, in series, or in any combination thereof.

[0015] In one or more embodiments, the process includes adding less than 0.3 mol% of hydrogen gas to a solution polymerization reactor to produce an effluent feed. In one or more embodiments, the hydrogen gas feed is 0-0.27 mol%, 0-0.25 mol%, 0-0.23 mol%, 0-0.22 mol%, 0-0.20 mol%, 0-0.18 mol%, 0-0.15 mol%, 0-0.12 mol%, or 0-0.10 mol%.

[0016] In embodiments, ethylene and at least one olefin monomer can be polymerized in the presence of a catalyst to produce a multimodal ethylene copolymer composition as described herein. The olefin monomer may be an α-olefin comonomer. Typically, an α-olefin monomer has 20 or fewer carbon atoms. For example, an α-olefin copolymer monomer may have 3 to 10 carbon atoms or 3 to 8 carbon atoms. Exemplary α-olefin copolymer monomers include, but are not limited to, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, and 4-methyl-1-pentene. For example, one or more α-olefin comonomers may be selected from the group consisting of propylene, 1-butene, 1-hexene, and 1-octene, or alternatively, from the group consisting of 1-hexene and 1-octene. In some embodiments, the α-olefin comonomer and process solvent may be purified using molecular sieves before being introduced into the solution polymerization reactor system. The solvent, monomer, comonomer, and hydrogen may be combined and supplied to the solution polymerization reactor system. Exemplary solvents include, but are not limited to, isoparaffins. For example, such solvents are commercially available from ExxonMobil Chemical under the name ISOPAR(trademark)E. In some embodiments, the combined feed may be at a controlled temperature of 5°C to 50°C, 5°C to 25°C, 5°C to 10°C, 10°C to 50°C, 10°C to 25°C, or 25°C to 50°C.

[0017] In some embodiments, the reactor temperature is 150°C or higher. In some embodiments, the reactor temperature is 150°C to 300°C. In one or more embodiments, the reactor temperature is 150°C to 200°C.

[0018] The catalyst systems, which will be described in more detail in subsequent sections, are used in the polymerization of olefins to produce the multimodal ethylene copolymer compositions described herein. As previously stated, the catalyst system in the solution polymerization reactor system may include at least one first catalyst that produces bulk low molecular weight (LMW) ethylene components and at least one second catalyst that produces high molecular weight (HMW) ethylene components.

[0019] In one embodiment, a multimodal ethylene copolymer composition may be produced via a solution polymerization process, where ethylene and optionally one or more α-olefins are polymerized in the presence of a first catalyst to produce a bulk low molecular weight (LMW) ethylene component. As used herein, "bulk" may refer to a component that constitutes more than 50% of the composition based on the total weight of the composition. In one or more embodiments, the first catalyst may have a first catalytic efficiency of 1,000 kg polymer / g metal to 30,000 kg polymer / g metal. In further embodiments, the first catalyst is 1,000 kg polymer / g metal to 25,000 kg polymer / g metal, 1,000 kg polymer / g metal to 20,000 kg polymer / g metal, 1,000 kg polymer / g metal to 15,000 kg polymer / g metal, 1,000 kg polymer / g metal to 10,000 kg polymer / g metal, 1,000 kg polymer / g metal to 5,000 kg polymer / g metal, 5,000 kg polymer / g metal to 25,000 kg polymer / g metal, 5,000 kg polymer / g metal to 20,000 kg polymer / g metal, 5,000 kg polymer / g metal to 15, It may have low molecular weight catalytic efficiencies of 000 kg polymer / g metal, 5,000 kg polymer / g metal to 10,000 kg polymer / g metal, 10,000 kg polymer / g metal to 25,000 kg polymer / g metal, 10,000 kg polymer / g metal to 20,000 kg polymer / g metal, 10,000 kg polymer / g metal to 15,000 kg polymer / g metal, 15,000 kg polymer / g metal to 25,000 kg polymer / g metal, 15,000 kg polymer / g metal to 20,000 kg polymer / g metal, or 1,000 kg polymer / g metal to 25,000 kg polymer / g metal.

[0020] In one embodiment, a multimodal ethylene copolymer composition may be produced via a solution polymerization process, where ethylene and optionally one or more α-olefins are polymerized in the presence of a second catalyst to produce a high molecular weight (HMW) ethylene-based component. In one or more embodiments, the second catalyst may have a second efficiency of 1,000 kg polymer / g metal to 100,000 kg polymer / g metal. In further embodiments, the second catalyst may have a second efficiency of 1,000 kg polymer / g metal to 75,000 kg polymer / g metal, 1,000 kg polymer / g metal to 50,000 kg polymer / g metal, or 1,000 kg polymer / g metal to 25,000 kg polymer / g metal. In further embodiments, the second catalyst is 1,000 kg polymer / g metal to 25,000 kg polymer / g metal, 1,000 kg polymer / g metal to 20,000 kg polymer / g metal, 1,000 kg polymer / g metal to 15,000 kg polymer / g metal, 1,000 kg polymer / g metal to 10,000 kg polymer / g metal, 1,000 kg polymer / g metal to 5,000 kg polymer / g metal, 5,000 kg polymer / g metal to 25,000 kg polymer / g metal, 5,000 kg polymer / g metal to 20,000 kg polymer / g metal, 5,000 kg polymer / g metal to 1 The second catalyst may have a second efficiency of 5,000 kg polymer / g metal, 5,000 kg polymer / g metal to 10,000 kg polymer / g metal, 10,000 kg polymer / g metal to 25,000 kg polymer / g metal, 10,000 kg polymer / g metal to 20,000 kg polymer / g metal, 10,000 kg polymer / g metal to 15,000 kg polymer / g metal, 15,000 kg polymer / g metal to 25,000 kg polymer / g metal, 15,000 kg polymer / g metal to 20,000 kg polymer / g metal, or 1,000 kg polymer / g metal to 25,000 kg polymer / g metal. In one or more embodiments, the second catalyst may exhibit a second reactivity ratio of less than 20. In further embodiments, the second catalyst may exhibit a second reactivity ratio of less than 20, less than 15, or less than 10. In further embodiments, the second catalyst may exhibit a first reactivity ratio of 10-20, 10-15, or 15-20.

[0021] In some embodiments, the multimodal ethylene copolymer composition may be produced via a solution polymerization process in a double reactor system, such as a double-loop reactor system, where ethylene and optionally one or more α-olefins are polymerized in a first reactor in the presence of a low molecular weight catalyst system to produce bulk low molecular weight (LMW) ethylene components and ethylene, and optionally one or more α-olefins are polymerized in a second reactor in the presence of a high molecular weight catalyst system to produce high molecular weight (HMW) ethylene components. In addition, one or more co-catalysts may be present.

[0022] In some embodiments, multimodal ethylene copolymer compositions may be produced via a solution polymerization process in a dual reactor system, where the first reactor is a continuous stirred reactor and the second polymerization reactor is a non-stirred polymerization reactor, such as a non-stirred tank reactor or a tubular reactor. In one or more embodiments, the non-stirred reactor is a plug-flow reactor or a piston-flow reactor. The term "non-stirred reactor" refers to a reactor that does not involve mechanical stirring, such as stirring by a stirrer, mixer, or kneader. Examples of non-stirred reactors include plug-flow reactors, tank reactors, and loop reactors, all of which do not have stirrers, mixers, or the like.

[0023] In embodiments, the solution polymerization reactor system may include one or more reactors operating at temperatures above 150°C. In embodiments, the solution polymerization reactor system may include one or more reactors operating at temperatures of 160°C to 200°C, 160°C to 190°C, 160°C to 180°C, 160°C to 170°C, 170°C to 200°C, 170°C to 190°C, 170°C to 180°C, 180°C to 200°C, 180°C to 190°C, or 190°C to 200°C. Operating the solution polymerization reactor at high reactor temperatures (>150°C) can increase the production rate and reduce energy consumption while still producing polyethylene products with acceptable catalytic efficiency and process control.

[0024] The reactor monomer feed (ethylene) stream is pressurized to a pressure higher than the reaction pressure of 525 psig via a mechanical compressor. The solvent and comonomer (1-octene) feeds are pressurized to a pressure higher than the reaction pressure of 525 psig via a mechanical positive displacement pump.

[0025] Immediately after each fresh injection point, the supply stream is mixed with the contents of the circulating polymerization reactor using static mixing elements. The effluent from the polymerization reactor (containing solvent, monomer, comonomer, hydrogen, catalyst components, and molten polymer) is exited through the first reactor loop and passed through a control valve (which maintains the pressure of the first reactor at a specified target). As the stream exits the reactor, it is brought into contact with water to halt the reaction. In addition, various additives such as antioxidants may be added at this point. The stream is then passed through another set of static mixing elements to uniformly disperse catalyst killers and additives.

[0026] Following the addition of additives, the effluent (containing solvent, monomers, copolymer monomers, hydrogen, catalyst components, and molten polymer) passed through a heat exchanger to raise the stream temperature in preparation for the separation of the polymer from other lower-boiling point reaction components. The stream was then placed into a two-stage separation and defoliation system, where the polymer was separated from the solvent, hydrogen, and unreacted monomers and copolymer monomers. The separated and defoliated polymer molten material was pumped through a die specially designed for underwater pelletization, cut into uniform solid pellets, dried, and transferred to storage boxes.

[0027] Catalyst system In one or more embodiments, specific embodiments of catalyst systems that can be used to produce the multimodal ethylene copolymer compositions described herein are described here. 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.

[0028] The term "independently selected" means that the R , R 2 , R 3 , R 4 , and R 5 groups, such as, can be the same or different (e.g., R 1 , R 2 , R 3 , R 4 , and R 5 are all substituted alkyl, or R 1 and R 2 are substituted alkyl and R 3 can be aryl, etc.). It is used herein to indicate such. The use of the singular includes the use of the plural and vice versa (e.g., a hexane solvent includes multiple hexanes). The named R groups will generally have a structure that is recognized to correspond to the R groups having that name in the art. These definitions are intended to supplement and illustrate, not exclude, definitions known to those skilled in the art.

[0029] The term "precursor catalyst" refers to a compound that has catalytic activity when combined with an activator. The term "activator" refers to a compound that chemically reacts with the precursor catalyst to convert it into a catalytically active catalyst. As used herein, the terms "cocatalyst" and "activator" are interchangeable terms.

[0030] When used to describe a chemical group containing a particular carbon atom, the bracketed expression in the form of "(C x ~C y )" means that the unsubstituted form of the chemical group has from x to y carbon atoms including x and y. For example, (C1~C 40 ) alkyl is an alkyl group having 1 to 40 carbon atoms in its unsubstituted form. In some embodiments and general structures, a particular chemical group may be substituted by one or more substituents such as R S . The bracketed "(C x-C y The chemical group R is defined using ) S The substitution version is any base R S Depending on the identity, it may contain more than y carbon atoms. For example, "R S Strictly speaking, one group R 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 substituent R, defined using ")", contains one or more carbon atoms in the chemical group. S When substituted by, the minimum and maximum total number of carbon atoms in the chemical group is such that both x and y contain all carbon atoms of substituent R. S This is determined by adding up the total number of carbon atoms from which they originate.

[0031] The term "substitution" means that at least one hydrogen atom (-H) bonded to a carbon or heteroatom or functional group of the corresponding unsubstituted compound is a substituent (e.g., R S The term "oversubstituted" means that all hydrogen atoms (H) bonded to the carbon or heteroatom of the corresponding unsubstituted compound or functional group are replaced 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.

[0032] The term "-H" refers to hydrogen or a hydrogen radical covalently bonded to another atom. "Hydrogen" and "-H" are interchangeable and mean the same thing unless otherwise specified.

[0033] "halogen atom", "halogen", "halide", "saturated", "unsaturated", "(C1~C 50 )) Hydrocarbyl", (C1~C 50 )alkyl", (C1~C 18)alkyl", (C6~C 50 )Arial," (C3~C 50 )Cycloalkyl", (C1~C 50 )alkylene, heteroatom, and C1~C 50 The term "heteroalkyl" is defined in the patent application with publication number WO2020185494A1.

[0034] According to some embodiments, the catalyst system for producing a multimodal ethylene copolymer composition comprises a metal-ligand complex according to formula (I).

[0035] [ka]

[0036] In formula (I), M is a metal selected from scandium, titanium, zirconium, hafnium, or lanthanide metals, 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 ligand or a bidentate ligand, if n is 2, each X is a monodentate ligand, and they are 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 40Each 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 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).

[0037] [ka]

[0038] In equations (II), (III), and (IV), R 31~35 , R 41~48 , or R 51~59 Each of these is independent of (C1~C 40 ) Hydrocarbyl, (C1~C 40 ) Heterohydrocarbyl, -Si(R C )3, -Ge(RC )3, -P(R P )2, -N(R N )2, -N=CHR C , -OR C , -SR C , -NO2, -CN, -CF3, R C S(O)-, R C S(O)2-, (R C )2C=N-, R C C(O)O-, R C OC(O)-, R C C(O)N(R N )-, (R N )2NC(O)-, halogen, or -H, provided that at least one of R 1 or R 8 is a radical having formula (II), formula (III), or formula (IV). ​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​In some embodiments, the multimodal ethylene copolymer 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.

[0041] In one or more embodiments, the first or second catalyst system can produce polymers having a natural molecular weight greater than 100,000 g / mol. In some embodiments, the other of the first or second catalyst system (which cannot produce polymers greater than 100,000 g / mol) can produce polymers having a natural molecular weight less than 80,000 g / mol. The natural molecular weight of the polymer is measured in a single 1-Gal reactor at a reactor temperature of at least 160°C, using ethylene pressure of 320 psi, 60 g of 1-octene, and 0 H2 in the presence of 1250 g of ISOPAR-E. The term "natural molecular weight" refers to the weight-average molecular weight of the polymer produced by the catalyst in the absence of hydrogen.

[0042] In various embodiments, a first catalyst system can produce a first polymer having a natural molecular weight, and a second catalyst system can produce a second polymer having a natural molecular weight having a difference of at least 80,000 g / mol from the natural molecular weight of the first polymer. In some embodiments, the difference in molecular weight between the first and second polymers is 80,000 g / mol to 2,000,000 g / mol. In some embodiments, the difference in molecular weight between the first and second polymers is at least 90,000 g / mol, at least 100,000 g / mol, at least 120,000 g / mol, or at least 150,000 g / mol. The natural molecular weight of the polymers is measured in a single 1 Gal reactor in the presence of 1250 grams of ISOPAR-E, at an ethylene pressure of 320 psi, 60 g of 1-octene, 0 H2, and a reactor temperature of at least 160°C.

[0043] cocatalyst component A catalyst system comprising the metal-ligand complex of formula (I) may be catalytically activated by any technique well known in the art for activating metal catalysts in olefin polymerization reactions. For example, a system comprising the metal-ligand complex of formula (I) may 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 alumoxanes (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.

[0044] Lewis acid activators (co-catalysts) are as described herein, comprising 1 to 3 (C1 to C 20 )Includes a group 13 metal compound containing a hydrocarbyl substituent.In one embodiment, the group 13 metal compound is tri((C1~C 20 )hydrocarbyl) substituted aluminum or tri((C1~C 20 The compound is a tri(hydrocarbyl)-boron compound. In the embodiment, the group 13 metal compound is tri((C1~C 20 )hydrocarbyl)-boron compounds, tri((C1~C 10 )Alkyl) Aluminum, Tri((C6~C 18The aryl)boron compounds and their halogenated (including perhalated) derivatives. In further embodiments, the Group 13 metal compound is tris(fluorosubstituted phenyl)borane, 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 in the formula, each (C1~C 20 ) If two or more hydrocarbyl molecules are present, they may be the same or different.

[0045] A combination of neutral Lewis acid activators (co-catalysts) is tri((C1~C4)alkyl)aluminum and halogenated tri((C6~C 18Examples include mixtures containing aryl)boron compounds, particularly combinations with tris(pentafluorophenyl)borane. Embodiments include combinations of such neutral Lewis acid mixtures with polymers or oligomeric almoxanes, and combinations of a single neutral Lewis acid, particularly tris(pentafluorophenyl)borane, with polymers or oligomeric almoxanes. The molar ratio of (metal-ligand complex):(tris(pentafluorophenylborane):(almoxane) [e.g., Group 4 metal-ligand complex):(tris(pentafluorophenylborane):(almoxane)] is 1:1:1 to 1:10:30, and in embodiments, 1:1:1.5 to 1:5:10.

[0046] A catalyst system containing a metal-ligand complex of formula (I) can be activated to form an activated catalyst composition in combination with one or more co-catalysts, such as a cation-forming co-catalyst, a strong Lewis acid, or a combination thereof. Suitable activation 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 methylaluminoxane (MMAO), bis(hydrogenated tulose alkyl)methyl, and tetrakis(pentafluorophenyl)borate (1 - Examples include, but are not limited to, amines and combinations thereof.

[0047] In some embodiments, one or more of the aforementioned activation co-catalysts are used in combination with each other. Particularly preferred combinations are tri((C1-C4)hydrocarbyl)aluminum, tri((C1-C4)hydrocarbyl)borane, or a mixture of ammonium borate with an oligomer or polymer-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 activation co-catalysts is 1:10,000 to 100:1. In some embodiments, this ratio is at least 1:5000, in some embodiments at least 1:1000 and 10:1 or less, and in some embodiments 1:1 or less. When an almoxane is used alone as an activation co-catalyst, the number of moles of the 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 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).

[0048] composition It has been found that by carrying out the processes described above, a multimodal ethylene copolymer composition having improved melt strength can be produced. The properties of the multimodal ethylene copolymer composition according to the embodiments disclosed and described herein are provided hereby. It should be understood that by changing the various process conditions described in the embodiments above, a multimodal ethylene copolymer composition having different and desirable properties can be produced. The properties listed below are described in separate paragraphs, but it should be understood that by changing the various process conditions considered above, the properties in any of the following paragraphs can be combined with the properties in any of the following paragraphs. Thus, a multimodal ethylene copolymer composition having any combination of the various properties listed below can be envisioned and produced according to the embodiments.

[0049] In one or more embodiments, the multimodal ethylene copolymer composition is 0.900 g / cm³ 3 ~0.940g / cm 3 It may have a density of 0.900 g / cm³. For example, embodiments of the multimodal ethylene copolymer compositions of this disclosure have a density of 0.900 g / cm³. 3 ~0.925g / cm 3 , 0.900 g / cm³ 3 ~0.920g / cm 3 , 0.900 g / cm³ 3 ~0.918 g / cm³ 3 , 0.900 g / cm³ 3 ~0.916 g / cm³ 3 , 0.900 g / cm³ 3 ~0.914 g / cm³ 3 , 0.900 g / cm³ 3 ~0.912 g / cm³ 3 , 0.900 g / cm³ 3 ~0.910 g / cm³ 3 , 0.900 g / cm³ 3 ~0.908 g / cm³ 3 , 0.900 g / cm³ 3 ~0.906 g / cm³ 3 , 0.900 g / cm³ 3~0.904g / cm 3 、0.900g / cm 3 ~0.902g / cm 3 、0.902g / cm 3 ~0.920g / cm 3 、0.902g / cm 3 ~0.918g / cm 3 、0.902g / cm 3 ~0.916g / cm 3 、0.902g / cm 3 ~0.914g / cm 3 、0.902g / cm 3 ~0.912g / cm 3 、0.902g / cm 3 ~0.910g / cm 3 、0.902g / cm 3 ~0.908g / cm 3 、0.902g / cm 3 ~0.906g / cm 3 、0.902g / cm 3 ~0.904g / cm 3 、0.904g / cm 3 ~0.920g / cm 3 、0.904g / cm 3 ~0.918g / cm 3 、0.904g / cm 3 ~0.916g / cm 3 、0.904g / cm 3 ~0.914g / cm 3 、0.904g / cm 3 ~0.912g / cm 3 、0.904g / cm 3 ~0.910g / cm 3 、0.904g / cm 3 ~0.908g / cm 3 、0.904g / cm 3 ~0.906g / cm 3 、0.906g / cm 3 ~0.920g / cm 3 、0.906g / cm 3 ~0.918g / cm 3 、0.906g / cm 3 ~0.916g / cm 3 、0.906g / cm3 ~0.914g / cm 3 、0.906g / cm 3 ~0.912g / cm 3 、0.906g / cm 3 ~0.910g / cm 3 、0.906g / cm 3 ~0.908g / cm 3 、0.908g / cm 3 ~0.920g / cm 3 、0.908g / cm 3 ~0.918g / cm 3 、0.908g / cm 3 ~0.916g / cm 3 、0.908g / cm 3 ~0.914g / cm 3 、0.908g / cm 3 ~0.912g / cm 3 、0.908g / cm 3 ~0.910g / cm 3 、0.910g / cm 3 ~0.920g / cm 3 、0.910g / cm 3 ~0.918g / cm 3 、0.910g / cm 3 ~0.916g / cm 3 、0.910g / cm 3 ~0.914g / cm 3 、0.910g / cm 3 ~0.912g / cm 3 、0.912g / cm 3 ~0.920g / cm 3 、0.912g / cm 3 ~0.918g / cm 3 、0.912g / cm 3 ~0.916g / cm 3 、0.912g / cm 3 ~0.914g / cm 3 、0.914g / cm 3 ~0.920g / cm 3 、0.914g / cm 3 ~0.918g / cm 3 、0.914g / cm 3 ~0.916g / cm 3, 0.916 g / cm³ 3 ~0.920g / cm 3 , 0.916 g / cm³ 3 ~0.918 g / cm³ 3 , 0.918 g / cm³ 3 ~0.920g / cm 3 , or the density may be any combination of these ranges.

[0050] In one or more embodiments, the multimodal ethylene copolymer composition may have a melt index (I2) of 0.50 g / 10 min (g / 10 min) to 10.0 g / 10 min when measured at 190°C and 2.16 kg in accordance with ASTM D-1238. When measured according to D-1238, the following ranges apply: 0.5g / 10 min to 10.0g / 10 min, 0.5g / 10 min to 9.0g / 10 min, 0.5g / 10 min to 8.0g / 10 min, 0.5g / 10 min to 7.0g / 10 min, 0.5g / 10 min to 6.0g / 10 min, 0.5g / 10 min to 5.0g / 10 min, 0.5g / 10 min to 4.0g / 10 min, 0.5g / 10 min to 3.0g / 10 min, 0.5g / 10 min to 2.0g / 10 min, 0.5g / 10 min to 1.0g / 10 min, 1.0g / 10 min~10.0g / 10min, 1.0g / 10min~9.0g / 10min, 1.0g / 10min~8.0g / 10min, 1.0g / 10min~7.0g / 10min, 1.0g / 10min~6.0g / 10min, 1.0g / 10min~5.0g / 10min, 1 .0g / 10min~4.0g / 10min, 1.0g / 10min~3.0g / 10min, 1.0g / 10min~2.0g / 10min, 2.0g / 10min~10.0g / 10min, 2.0g / 10min~9.0g / 10min, 2.0g / 10min~8.0g / 10 minutes, 2.0g / 10 minutes ~ 7.0g / 10 minutes, 2.0g / 10 minutes ~ 6.0g / 10 minutes, 2.0g / 10 minutes ~ 5.0g / 10 minutes, 2.0g / 10 minutes ~ 4.0g / 10 minutes, 2.0g / 10 minutes ~ 3.0g / 10 minutes, 3.0g / 10 minutes ~ 10.0g / 10min, 3.0g / 10min~9.0g / 10min, 3.0g / 10min~8.0g / 10min, 3.0g / 10min~7.0g / 10min, 3.0g / 10min~6.0g / 10min, 3.0g / 10min~5.0g / 10min, 3.0g / 10 minutes~4.0g / 10 minutes, 4.0g / 10 minutes~10.0g / 10 minutes, 4.0g / 10 minutes~9.0g / 10 minutes, 4.0g / 10 minutes~8.0g / 10 minutes, 4.0g / 10 minutes~7.0g / 10 minutes, 4.0g / 10 minutes~6.0g / 10 min, 4.0g / 10min~5.0g / 10min, 5.0g / 10min~10.0g / 10min, 5.0g / 10min~9.0g / 10min, 5.0g / 10min~8.0g / 10min, 5.0g / 10min~7.0g / 10min, 5.0g / 10min~6.The melt index (I2) may be 0g / 10 min, 6.0g / 10 min to 10.0g / 10 min, 6.0g / 10 min to 9.0g / 10 min, 6.0g / 10 min to 8.0g / 10 min, 6.0g / 10 min to 7.0g / 10 min, 7.0g / 10 min to 10.0g / 10 min, 7.0g / 10 min to 9.0g / 10 min, 7.0g / 10 min to 8.0g / 10 min, 8.0g / 10 min to 10.0g / 10 min, 8.0g / 10 min to 9.0g / 10 min, 9.0g / 10 min to 10.0g / 10 min, or any combination of these ranges.

[0051] According to the embodiment, the multimodal ethylene copolymer composition may have a molecular weight distribution in the range of 2.0 to 6.0 (expressed as the ratio of weight-average molecular weight to number-average molecular weight (Mw / Mn)). For example, the multimodal ethylene copolymer composition may have a molecular weight distribution in the range of 2.0 to 5.5, 2.0 to 5.0, 2.0 to 4.5, 2.0 to 4.0, 2.0 to 3.5, 2.0 to 2.5, 2.5 to 6.0, 3.0 to 5.5, 3.0 to 5.0, 3.0 to 4.5, 3.0 to 4.0, 3.0 to 3.5, 3.5 to 6.0, 3.5 The molecular weight distribution may be ~5.5, 3.5~5.0, 3.5~4.5, 3.5~4.0, 4.0~6.0, 4.0~5.5, 4.0~5.0, 4.0~4.5, 4.5~6.0, 4.5~5.5, 4.5~5.0, 5.0~6.0, 5.0~5.5, or 5.5~6.0, or any combination of these ranges. As described herein, the molecular weight distribution may be calculated according to gel permeation chromatography (GPC) techniques as described herein.

[0052] According to the embodiment, a multimodal ethylene copolymer composition may have an activation energy (Ea) exceeding 30 kJ / mol, as determined by dynamic mechanical analysis. The activation energy is calculated from rheological time-temperature superposition viscosity data obtained from melt rheological frequency sweeps. These measurements were performed using a TA Instruments Advanced Rheometric Expansion System (ARES) equipped with 25 mm parallel plates and using pure nitrogen. Linear viscoelastic responses were measured at three different temperatures of 150°C, 190°C, and 230°C, using frequencies of 0.1–500 rad / s, 0.1–100 rad / s, and 0.01–100 rad / s, respectively. Strain was modified based on the torque output of the transducer to ensure that the torque remained within acceptable limits. The stress response was analyzed in terms of amplitude and phase, from which the storage modulus and loss modulus, as well as the dynamic melt viscosity, were calculated. The temperature dependence of a linear viscoelastic curve can be predicted by shifting the modulus curve across the frequency axis (X-axis) relative to a reference using a set of shift coefficients. This concept is generally known as time-temperature superposition. This technique involves shifting curves at different temperatures so that they overlap and form a single curve, also known as the master curve. The shift coefficients were generated using RepTate software. The reference temperature was selected as 190°C. The Arrhenius equation relates the horizontal shift coefficients to the activation energy and reference temperature according to the following equation:

[0053]

number

[0054] In further embodiments, the multimodal ethylene copolymer composition may have an activation energy (Ea) of 30 kJ / mol to 60 kJ / mol, 30 kJ / mol to 50 kJ / mol, 30 kJ / mol to 40 kJ / mol, 40 kJ / mol to 60 kJ / mol, 40 kJ / mol to 50 kJ / mol, or 50 kJ / mol to 60 kJ / mol, as determined by dynamic mechanical analysis.

[0055] According to the embodiment, the multimodal ethylene copolymer composition may have a melt strength (MS) satisfying the following formula 1:

[0056]

number

[0057] In Equation 2, x is 15 or greater, y is 1 or greater, and I2 is the melt index of the copolymer measured in accordance with ASTM 1238 at 2.16 kg and 190°C. According to one or more embodiments, the multimodal ethylene copolymer composition may have a melt strength of at least 5 centinewtons (cN). Further embodiments include multimodal ethylene copolymer compositions with concentrations of 5cN to 50cN, 5cN to 45cN, 5cN to 40cN, 5cN to 35cN, 5cN to 30cN, 5cN to 25cN, 5cN to 20cN, 5cN to 15cN, 5cN to 10cN, 10cN to 50cN, 10cN to 45cN, 10cN to 40cN, 10cN to 35cN, 10cN to 30cN, 10cN to 25cN, 10cN to 20cN, 10cN to 15cN, 15cN to 50cN, 15cN to 45cN, 15cN to 40cN, 15cN to 35cN, and 15cN to 30cN. It had a melt strength of 15cN~25cN, 15cN~20cN, 20cN~50cN, 20cN~45cN, 20cN~40cN, 20cN~35cN, 20cN~30cN, 20cN~25cN, 25cN~50cN, 25cN~45cN, 25cN~40cN, 25cN~35cN, 25cN~30cN, 30cN~50cN, 30cN~45cN, 30cN~40cN, 30cN~35cN, 35cN~50cN, 35cN~45cN, 35cN~40cN, 40cN~50cN, 40cN~45cN, or 45cN~50cN.

[0058] In some embodiments, a multimodal ethylene copolymer composition may have a ratio (V0.1 / V100) greater than 5 between the viscosity measured at 0.1 radians / second and 190°C and the viscosity measured at 100 radians / second and 190°C, as determined by dynamic mechanical analysis. In further embodiments, a multimodal ethylene copolymer composition may have a ratio (V0.1 / V100) of 5-30, 5-25, 5-20, 5-15, 5-10, 10-30, 10-25, 10-20, 10-15, 15-30, 15-25, 15-20, 20-30, 20-25, or 25-30, as determined by dynamic mechanical analysis.

[0059] In the embodiment, cumulative distribution fractions (CDF) of light scattering analysis are obtained for molecular weights exceeding 500,000 g / mol. LS ) is 8% or more. In one or more embodiments, the molecular weight exceeding 500,000 g / mol is 8% to 50%, 10% to 50%, 20% to 50%, 30% to 50%, or 20% to 40%, based on the total percentage of the multimodal ethylene copolymer.

[0060] In the embodiment, the multimodal ethylene copolymer composition may have a high molecular weight fraction of 8% to 50%, calculated by measuring the area fraction of a low-angle light scattering (LALLS) detector chromatogram exceeding 500,000 g / mol. In the embodiment, the high molecular weight fraction calculated by measuring the area fraction of a low-angle light scattering (LALLS) detector chromatogram exceeding 500,000 g / mol may be 8% to 40%, 8% to 30%, 10% to 50%, 10% to 40%, 10% to 30%, 20% to 50%, 20% to 40%, 20% to 30%, 30% to 50%, 30% to 40%, or 40% to 50%.

[0061] In embodiments, the multimodal ethylene copolymer composition may have a low molecular weight fraction greater than 50%, calculated by measuring the area fraction of a low-angle light scattering (LALLS) detector chromatogram of less than 500,000 g / mol. In embodiments, the low molecular weight fraction calculated by measuring the area fraction of a low-angle light scattering (LALLS) detector chromatogram of less than 500,000 g / mol may be 50%~92%, 50%~90%, 50%~80%, 50%~70%, 50%~60%, 60%~92%, 60%~90%, 60%~80%, 60%~70%, 70%~92%, 70%~90%, 70%~80%, 80%~92%, 80%~90%, or 90%~92%. Conventionally, it was considered ideal to have as much high molecular weight material as possible, as high molecular weight leads to a higher level of entanglement, which improves the properties of LLDPE. Therefore, low molecular weight material was kept to a minimum. However, the multimodal ethylene copolymer compositions according to the embodiments disclosed and described herein exhibit unique and unexpected properties compared to commercially available LDPE products when the high molecular weight fraction, calculated by measuring the area fraction of the low-angle light scattering (LALLS) detector chromatogram above 500,000 g / mol, is between 8% and 50%.

[0062] A multimodal ethylene copolymer composition may further contain one or more additives. Such additives include, but are not limited to, antistatic agents, color enhancers, dyes, lubricants, pigments, primary antioxidants, secondary antioxidants, processing aids, UV stabilizers, and combinations thereof. A multimodal ethylene copolymer composition may contain any amount of additives. Based on the total weight of the multimodal ethylene copolymer composition, such additives may constitute about 0 to about 10 percent by combined weight. A multimodal ethylene copolymer composition may further contain fillers, which may include, but are not limited to, organic or inorganic fillers. Based on the total weight of the multimodal ethylene copolymer composition, such fillers may constitute about 0 to about 20 percent by weight, for example, calcium carbonate, talc, or Mg(OH)2. A multimodal ethylene copolymer composition may be further blended with one or more polymers to form a blend.

[0063] Test method Unless otherwise specified herein, the following analytical methods are used in describing aspects of this disclosure.

[0064] Melt Index Melt index I2 (or I2) and I 10 (or I10) were measured at 190°C and under loads of 2.16 kg and 10 kg, respectively, according to ASTM D-1238 (Method B). The values ​​were reported in g / 10 min.

[0065] density Samples for density measurement were prepared according to ASTM D4703. Within one hour of sample pressurization, measurements were performed according to ASTM D792, Method B.

[0066] Triple-detector 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), and a 4-capillary viscometer (DV) coupled to a Precision Detectors (now Agilent Technologies) Model 2040 2-angle laser scattering (LS) detector. For all absolute light scattering measurements, a 15-degree angle was used. The autosampler oven compartment was set to 160°C, and the column and detector compartments were set to 150°C. The columns used were four Agilent "Mixed A" 30 cm, 20 micron 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 milliliter / minute.

[0067] The total plate count of the GPC column set was performed using decane introduced into blank samples via a micropump controlled by the PolymerChar GPC-IR system. The plate count of the chromatography system should be greater than 18,000 for four Agilent "Mixed A" 30 cm² 20 micron linear mixed-bed columns.

[0068] The sample was prepared semi-automatically using PolymerChar's "Instrument Control" software, with a target weight of 2 mg / mL. The solvent (containing 200 ppm BHT) was added to a vial with a pre-nitrogen-spurged septum cap via a PolymerChar high-temperature autosampler. The sample was dissolved at 160°C for 2 hours under "low-speed" shaking.

[0069] 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 calibrate the pump flow rate (nominal flow rate) for each sample by RV matching each decane peak in the sample (RV(FM sample)) with the decane peak in a narrow standard calibration (RV(FM calibrated)). It was then assumed that any change in the decane marker peak over time would correspond to a linear shift in the flow rate (effective flow rate) over the entire run. After calibrating the system based on the flow rate marker peaks, the effective flow rate (relative to the narrow standard calibration) was calculated as shown in Equation 3. Processing of the flow rate marker peaks was performed via PolymerChar GPCOne® software. An acceptable flow rate correction should be such that the effective flow rate is within ±0.5% of the nominal flow rate. Effective flow rate = Apparent flow rate * (RV(FM calibrated) / RV(FM sample)) (Equation 3)

[0070] Regarding the determination of viscometer and light scattering detector offsets from an IR5 detector, a systematic method for determining multiple detector offsets was developed by Balke, Mourey et al. (Mourey and Balke, Chromatography Polym. Chpt 12, (1992)) (Balke, Thitiratsakul, Lew, Cheung, Mourey, Chromatography Polym. Chpt 13, (1992)). Using PolymerChar GPCOne™ software, the results of triple detector log(MW and IV) obtained from linear homopolymer polyethylene standard materials (3.5>Mw / Mn>2.2) with molecular weights in the range of 115,000 to 125,000 g / mol were optimized to the results of narrow standard column calibration obtained from a narrow standard material calibration curve.

[0071] Absolute molecular weight data was obtained using PolymerChar GPCOne® software in a format consistent with that published by Zimm (Zimm, BH, J. Chem. Phys., 16, 1099 (1948)) and Kratochvil (Kratochvil, P., Classical Light Scattering from Polymer Solutions, Elsevier, Oxford, NY (1987)). The total injection concentration used in determining the molecular weight was obtained from the mass detector area and mass detector constant derived from one of the following: a suitable linear polyethylene homopolymer or a polyethylene standard material with a known weight-average molecular weight. The molecular weight calculated (using GPCOne®) was obtained using the light scattering constant derived from one or more of the polyethylene standards described below, and the refractive index concentration coefficient, dn / dc, of -0.104. Generally, the mass detector response (IR5) and light scattering constant (determined using GPCOne®) should be determined from linear reference materials having a molecular weight greater than approximately 50,000 g / mol. Calibration of the viscometer (determined using GPCOne®) can be achieved using the method described by the manufacturer, or alternatively, by using published values ​​of a suitable linear reference material such as Standard Reference Material (SRM) 1475 (available from the National Institute of Standards and Technology (NIST)). The specific viscosity area (DV) and injected mass for the calibration standard are used to calculate the viscometer constant (obtained using GPCOne®) related to its intrinsic viscosity. The chromatographic concentration is assumed to be low enough to eliminate the second viral coefficient effect (concentration effect on molecular weight).

[0072] Absolute weight average molecular weight (MW) (Abs)) is obtained (using GPCOne®) from a light scattering (LS) area integrated chromatogram (factored by the light scattering constant) divided by the mass reconstructed from the mass constant and mass detector (IR5) area. The molecular weight and intrinsic viscosity response are linearly extrapolated (using GPCOne®) at the edge of the chromatography where signal-to-noise is low. Other respective moments are Mn (Abs) and Mz (Abs) This is calculated according to equations 4-6 below.

[0073]

number

[0074] CDF calculation method Cumulative detector fraction (CDF) of low-angle laser light scattering (LALLS) detectors LS The calculation of ) is performed using the peak height (H) obtained by subtracting the baseline of the absolute molecular weight chromatogram. These values ​​are summed up across the entire chromatogram from high molecular weight to low molecular weight (from low retention volume to high retention volume, RV) in each data slice (j), essentially integrating the area of ​​the chromatogram. The proportion of the entire molecular weight chromatogram (or percentage if multiplied by 100) is obtained by ratio values ​​of 500,000 g / mol or greater to the lowest RV compared to the entire chromatogram, Equation 7.

[0075]

number

[0076] Procedure for NMR end-group analysis, including vinyl number determination. To determine the vinyl count, approximately 7 mg of polymer sample was packed into a 5 mm NMR tube with 0.6 mL of tetrachloroethane-d2 and 0.008 M chromium(III) acetylacetonate. The tube was purged with N2 and the cap was secured with Teflon tape. The prepared sample tube was heated in a heating block set to 125°C and repeatedly vortexed until a homogeneous solution was achieved, as evidenced by a consistent flow when the tube was tilted horizontally. The completed sample was inserted into a Bruker AVANCE 600 MHz system equipped with a 10 mm high-temperature cryoprobe set to 120°C. 1 The acquisition parameters for the 1H NMR spectrum were a 90-degree pulse, an acquisition time of 1.8 seconds, a relaxation delay of 10 seconds, a spectral center set to 2 ppm, a spectral width of 20 ppm, and 128 scans for signal averaging. The obtained source FIDs were exponentially multiplied, Fourier transformed, phase-aligned, baseline corrected, and integrated using MNOVA software.

[0077] Melt strength Melt strength tests were performed using either a Rheotester 2000 or Rheograph 25 capillary rheometer paired with a Rheotens model 71.97, all manufactured by Gottfert. The dies used in the tests had a diameter of 2 mm, a length of 30 mm, and an entry angle of 180 degrees. Each test was generally performed isothermally at 190°C.

[0078] During the test, pelletized samples were loaded into a capillary barrel and equilibrated at the test temperature for 10 minutes. A piston in the barrel then applied a constant force to the molten sample to achieve an apparent wall shear rate of 38.16 s⁻¹, and the molten material was extruded through the die at an exit velocity of approximately 9.7 mm / s. Located 100 mm below the die exit, the extruded material was guided through a pair of rheotense wheels, both accelerating at a constant velocity of 2.4 mm / s², and the response of the extruded material to the applied tensile force was measured. Note that the pair of rheotense wheels were serrated and spaced 0.4 mm apart. The results of this test were recorded using the RtensEvaluations2007 Excel macro to plot force against rheotense wheel velocity. For analysis, the force at which fracture occurred in the molten material was referred to as the molten strength of the material, and the corresponding rheotense wheel velocity at fracture was considered the tensile limit.

[0079] DMS frequency sweep For preparation, the test specimen was first placed in a 3.10 mm thick, 1.5 inch diameter chase and compressed using a Carver Hydraulic Press (Model #4095.4NE2003) at a pressure of 25,000 pounds at 190°C for 6.5 minutes. After cooling to room temperature, the specimen was removed and awaited rheological testing.

[0080] Dynamic Mechanical Spectroscopy (DMS) frequency sweeps are performed using 25 mm parallel plates at frequencies in the ranges of 0.01 to -100 rad / s, 0.1 to 100 rad / s, and 0.1 to 500 rad / s at 150°C, 190°C, and 230°C, respectively. The test gap separating the plates is 1.8 mm, and a strain satisfying linear viscoelastic conditions, typically 10%, is used. Each test is performed under nitrogen atmosphere and isothermal conditions. To begin the DMS test, the rheometer oven is first equilibrated at the desired test temperature for at least 30 minutes, after which the sample is loaded into the test shape. The sample is then equilibrated in the closed oven for 1 minute. Next, the test gap is set to 1.8 mm, and the sample is allocated 5 minutes to relax the resulting normal force. The oven is then quickly opened, and the sample is trimmed to ensure no bulging is present. The oven is then closed again, and the DMS measurement is started. During the test, the shear modulus (G'), viscosity coefficient (G"), and complex viscosity are measured.

[0081] All DMS frequency tests are performed using either an ARES-G2 or DHR-3 rheometer (both manufactured by TA Instruments). Data analysis is performed using TA Instruments TRIOS software.

[0082] Procedure for polymerization in a continuous reactor: Setup 1 The raw materials (ethylene, 1-octene) and process solvent (high-purity isoparaffin solvents with a narrow boiling point range, commercially available from Shell and ExxonMobil Corporation under the trademarks SBP 100-140 or Isopar-E) were purified using molecular sieves before being introduced into the reaction environment. Hydrogen was supplied into the pressurized cylinder as high-purity grade and not further purified. The reactor monomer feed (ethylene) stream was pressurized to a pressure higher than the reaction pressure via a mechanical compressor. The solvent and comonomer (1-octene) feeds were pressurized to a pressure higher than the reaction pressure via a mechanical positive displacement pump. Noryon's MMAO-3A or MMAO-7 were used as impurity scavengers and / or catalyst activators. Individual catalyst components (pre-catalysts or co-catalysts) were manually batch diluted to specific component concentrations using the purified solvent (Isopar E or SBP 100-140) and pressurized to a pressure higher than the reaction pressure. The co-catalyst is [HNMe(C)], which is commercially available from Boulder Scientific. 18 H 37 The compound is )2[B(C6F5)4], and unless otherwise specified, it is used in a ratio of 1.2 to the catalyst metal. All reaction feed flows were measured with a mass flow meter and independently controlled by a computer-controlled automatic valve control system.

[0083] Continuous solution polymerization was carried out in one or more of the following reactors: CSTR, loop, and / or plug-flow reactors. CSTR and loop reactors have independent control of all fresh solvent, monomer, comonomer, hydrogen, and catalyst component feeds. A fresh feed to a second reactor is optional (i.e., fresh solvent, monomer, comonomer, and hydrogen are not added to the second reactor). Plug-flow reactors have independent control of catalyst component feeds. The combined feed of solvent, monomer, copolymer monomer, and hydrogen to the reactor is temperature-controlled somewhere between 5°C and 50°C, typically 25°C. A fresh copolymer monomer feed to the polymerization reactor is supplied together with the solvent feed. The fresh solvent feed is typically controlled by each injector receiving half of the total fresh feed volume flow rate. The co-catalyst is supplied to the pro-catalyst based on a calculated specified molar ratio. Immediately after each fresh injection point, the feed stream is mixed with the contents of the circulating polymerization reactor using a static mixing element. The ratio of catalyst feed is adjusted to obtain the desired polymer MI, density, and melt strength. The effluent (containing solvent, monomer, copolymer monomer, hydrogen, catalyst components, and molten polymer) exits the polymerization reactor system and passes through a control valve (which maintains the reactor system pressure at a specified target). As the stream exits the reactor, it is brought into contact with water to stop the reaction. Various additives, such as antioxidants, could be added at this point. Next, the stream is passed through another set of static mixing elements to uniformly disperse catalyst killers and additives.

[0084] Following the addition of additives, the effluent (containing solvent, monomers, copolymer monomers, hydrogen, catalyst components, and molten polymer) passed through a heat exchanger to raise the stream temperature in preparation for the separation of the polymer from other low-boiling point reaction components. The stream was then placed into a two-stage separation and defoliation system, where the polymer was separated from the solvent, hydrogen, and unreacted monomers and copolymer monomers. The separated and defoliated polymer molten material was pumped through a die specially designed for underwater pelletization, cut into uniform solid pellets, dried, and transferred to storage boxes.

[0085] Procedure for polymerization in a continuous reactor: Setting 2 Before introducing them into the reaction environment, all raw materials (monomers and comonomers) and the process solvent (high-purity isoparaffin solvent with a narrow boiling point range, Isopar-E) are purified using molecular sieves. Hydrogen is supplied under pressure as a high-purity grade and is not purified further. The monomer feed stream to the reactor is pressurized to exceed the reaction pressure via a mechanical compressor. The solvent and comonomer feed streams are pumped to a pressure higher than 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 a mass flow meter and controlled independently by a computer-automated valve control system.

[0086] Two reactor systems are used in a series configuration. The first reactor is a continuous solution polymerization reactor consisting of a liquid-filled, adiabatic, continuously stirred tank reactor (CSTR). All fresh solvent, monomers, comonomers, hydrogen, and catalyst component feeds can be independently controlled. All fresh supply flows to the second reactor (solvent, monomers, comonomers, and hydrogen) are temperature-controlled to maintain a single solution phase by passing the feed flow through a heat exchanger. All fresh supplies to the second polymerization reactor are injected into the reactor at a single location. Catalyst components are injected into the second polymerization reactor separately from the fresh supplies. The supply of primary catalyst components is computer-controlled to maintain monomer conversion in the reactor at a specific value. Co-catalyst components are supplied based on their molar ratio to the primary catalyst component. Mixing in the second reactor can be provided by a stirrer. The effluent from the first polymerization reactor (containing solvent, monomer, comonomer, hydrogen, catalyst components, and polymer) flows out of the first reactor loop and is added to the second reactor separately from the catalyst components from an optional fresh feed.

[0087] The second reactor is a continuous solution polymerization reactor consisting of a liquid-filled, non-adiabatic, isothermal, circulating, loop reactor that mimics a continuous stirred-tank reactor (CSTR) for heat removal. All fresh solvent, monomer, comonomer, hydrogen, and catalyst component feeds are independently controlled. All fresh supply flows to the first reactor (solvent, monomer, comonomer, and hydrogen) are temperature-controlled to maintain a single solution phase by passing the feed flow through a heat exchanger. All fresh feeds to the first polymerization reactor are injected into the reactor at two locations, with approximately equal reactor volumes between each injection point. Fresh feed is controlled by each injector, receiving half of the total mass flow of fresh feed. Catalyst components are injected into the polymerization reactor separately from the fresh feed when fresh feed is added. The primary catalyst component feed is computer-controlled to maintain the reactor monomer conversion rate at a specific value and to produce polymers with the desired MI, density, and melt strength. Co-catalyst components are supplied based on their molar ratio to the primary catalyst component. Immediately after the injection point of each first reactor feed, the feed stream is mixed with the contents of a circulating polymerization reactor having a static mixing element. The contents of the first reactor are continuously circulated through a heat exchanger, which plays a role in removing most of the reaction heat, at the temperature of the coolant side, which plays a role in maintaining an isothermal reaction environment at a specific temperature. The circulation around the first reactor loop is provided by a pump.

[0088] The second reactor effluent enters a zone where a suitable reagent (water) is added and reacts with it to deactivate the effluent. The addition of antioxidants may also occur at this same point. 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 collected. The non-polymer stream passes through various devices that separate most of the ethylene removed from the system. Most of the solvent and unreacted comonomers are recycled back into the reactor after passing through a purification system. Small amounts of solvent and comonomers are purged from the process.

[0089] Reactor flow feed data flow corresponding to the values ​​in Table 2. The data is presented to take into account the complexity of the solvent recycling system and to allow for easier processing of the reaction system as a through-flow diagram.

[0090] Chain transfer constant calculation The chain transfer constant is calculated using the version of the Meioh equation shown in Equation 7, where Mn0 is Mn without hydrogen added to the reactor, and H2 and ethylene concentrations are the liquid phase concentrations. CTH This is the ratio of the hydrocracking rate constant to the rate constant of the chain transfer reaction. The reactor volume is 3.414 L, and the liquid phase ethylene concentration is estimated to be 0.539 M. The estimated hydrogen concentrations are 1.17 mM, 2.31 mM, 4.53 mM, 8.74 mM, and 16.3 mM for 10, 20, 40, 80, and 160 mmol of H2, respectively. The Mn value was calculated for each hydrogen load using Equation 8. Using the Solver function in MS Excel, c CTH By varying the value of , we minimized the sum of the squared deviations between the calculated Mn value and the experimental Mn value for all hydrogenation amounts simultaneously.

[0091]

number

[0092] One or more features of this disclosure are illustrated by the following embodiments.

[0093] The following catalysts were used in one or more of the examples described in more detail below.

[0094] [ka]

[0095] [ka]

[0096] Example 1: Preparation of compositions 1-8 Multimodal ethylene copolymer compositions 1 to 8, described according to one or more embodiments of "Modes for Carrying Out the Invention," were prepared by processes utilizing the catalysts and reactors described below. The reactor and supply conditions for the synthesis of composition 1 are provided in Table 1, for composition 2 in Table 2, and for compositions 3 to 7 in Table 3.

[0097] [Table 1]

[0098] [Table 2]

[0099] [Table 3]

[0100] Example 2: Preparation of comparative compositions C1-C3 Comparative compositions C1 to C3 were prepared by processes utilizing the catalysts and reactors described below.

[0101] 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) were purified using molecular sieves. Hydrogen was supplied under pressure as a high-purity grade and no further purification was performed. The reactor monomer feed stream was pressurized to a pressure exceeding the reaction pressure via a mechanical compressor. The solvent and comonomer feed streams were pumped to a pressure higher than the reaction pressure. Individual catalyst components were manually batch diluted with purified solvent and pressurized to exceed the above reaction pressure. All reaction feed streams were measured with mass flow meters and independently controlled by a computer-controlled automatic valve control system. Reactor and feed conditions for the synthesis of comparative compositions C1-C3 are provided in Table 5.

[0102] [Table 4]

[0103] Example 3: Comparative compositions C4-C8 Comparative compositions C4 and C5 are ethylene-based polymers produced via a high-pressure free-radical polymerization process. Comparative composition C6 is an ethylene-based polymer produced in a single reactor using a single catalyst. Comparative compositions C7 and C8 are bimodal ethylene-based polymers produced in a double reactor system with a single catalyst in each reactor.

[0104] Example 4: Preparation of comparative compositions C9-C19 Comparative compositions 9 to 19 were prepared by processes utilizing the catalysts and reactors described below.

[0105] [Table 5]

[0106] [Table 6]

[0107] Conditions: Run at 160°C: 320 psi ethylene, 60 g 1-octene, 0 H2, 1250 mL of Isopar E solvent. Run at 190°C: 410 psi ethylene, 65 g 1-octene, 0 H2, 1250 mL of Isopar E solvent. All runs: Mole fraction of ethylene in solution = 0.709.

[0108] * The reactivity ratio r1 is the reactivity ratio for monomer insertion after ethylene, and is calculated using the Mayo-Lewis equation.

[0109]

number

[0110] In Equation 9, r2 is the reactivity ratio for monomer insertion after comonomer (in this case, 1-octene), f1 is the mole fraction of ethylene in the feed, f2 is the mole fraction of comonomer (1-octene) in the feed, and F1 is the mole fraction of ethylene in the polymer. F1=1-F2 (formula 10)

[0111] In Equation 10, F2 is the mole fraction of 1-octene in the polymer. This value can be obtained experimentally by GPC analysis of the polymer.

[0112] The Mayo-Lewis equation can be solved using the GRG nonlinear solution method available in Microsoft Excel to find the r1 and r2 values ​​that give the best fit.

[0113] Example 5: Analysis of compositions 1-6 and comparative compositions 1-19. In Example 5, multimodal ethylene polymer compositions 1 to 6 and comparative compositions 1 to 19 were tested for the properties listed in Tables 8 to 10 according to the test methods described herein.

[0114] [Table 7] * Values ​​from absolute GPC analysis ** Values ​​from conventional GPC analysis

[0115] [Table 8]

[0116] [Table 9]

[0117] [Table 10]

[0118] As shown in Tables 7-9, Comparative Examples C1-C3 are produced using a single biphenylphenol (BPP) catalyst A. The resulting polymers have a high vinyl content, but the lack of high molecular weight components produced by the second catalyst results in low melt strength.

[0119] Comparative Examples C16-C19 were prepared using two BPP catalysts A and C in a series-configured double reactor. The level of hydrogen used in the reactor with BPP catalyst C (0.43-1.33 mol%) was considerably high. This level of H2 limited the ability of the BPP catalyst to build molecular weight, as seen in the CDF LS500,000 g / mol cutoff data, which ranged from 2.12-5.18%.

[0120] Examples 1-6 of the present invention were produced using two BPP catalysts in various reactor configurations, including single-reactor and double-reactor series, with reactors selected from CSTR, loop, and plug-flow reactor types. The hydrogen levels used to produce the examples of the present invention were much lower than those used to produce Comparative Examples 16-19.

[0121] For example, Example 2 of the present invention used hydrogen levels in the range of 0.03 to 0.3 mol%. Depending on the example of the present invention, when the hydrogen level is low, BPP catalyst C or D can produce a higher molecular weight polymer. This is reflected in the CDF LS 500,000 g / mol cutoff data, where these values ​​are in the range of 13 to 31%, which is considerably higher than Examples 16 to 19 of the present invention, which used higher levels of hydrogen.

[0122] Furthermore, while Examples 1-6 of the present invention exhibit improved rheological properties and a high melt strength of 36 cN, the melt strengths of Comparative Examples 1-3 and 16-19 were 6.2 cN or less, and these values ​​were achieved with polymers with lower MI (MI = 0.77 g / 10 min).

Claims

1. A process for producing multimodal ethylene copolymers, The process involves adding ethylene, at least one olefin monomer, at least a first catalyst system, and less than 0.3 mol% hydrogen gas to a solution polymerization reactor to produce an effluent feed at a reactor temperature of 150°C or higher, wherein the mol% hydrogen is based on the moles of ethylene in the feed. This includes supplying the effluent feed and the second catalyst system to the second reactor in the absence of fresh feed and hydrogen gas, The first catalyst system comprises a first procatalyst and a first activator, and the second catalyst system comprises a second procatalyst and optionally a second activator. At least one of the first catalyst system and the second catalyst system has a chain transfer constant of 0.005 to 1.

0. A process further comprising a high molecular weight fraction of the multimodal ethylene copolymer, which is 8-50% based on the total percentage of the multimodal ethylene copolymer, calculated by measuring the area fraction of a molecular weight chromatogram obtained from the absolute molecular weight by low-angle light scattering exceeding 500,000 g / mol.

2. Either the first catalyst system or the second catalyst system can produce a polymer having a natural molecular weight exceeding 100,000 g / mol, wherein the natural molecular weight of the polymer is obtained in a single 1 Gal reactor in the presence of 1250 g of ISOPAR-E, at an ethylene pressure of 320 psi, with an amount of 60 g of 1-octene, and 0 H ２ The process according to claim 1, and measured at a reactor temperature of at least 150°C.

3. The other of the first catalyst system and the second catalyst system can produce a polymer having a natural molecular weight of less than 150,000 g / mol, wherein the natural molecular weight of the polymer is obtained in a single 1 Gal reactor in the presence of 1250 g of ISOPAR-E, at an ethylene pressure of 320 psi, with an amount of 60 g of 1-octene, and 0 H ２ The process according to claim 2, and measured at a reactor temperature of at least 160°C.

4. The process according to claim 1, wherein the first catalyst system can produce a first polymer having a natural molecular weight, and the second catalyst system can produce a second polymer having a natural molecular weight having a difference of at least 80,000 g / mol from the natural molecular weight of the first polymer.

5. The process according to any one of claims 1 to 4, wherein the solution polymerization reactor is a continuous stirred tank reactor, a loop reactor, or a plug flow reactor.

6. The process according to any one of claims 1 to 5, wherein the second polymerization reactor includes a non-stirred reactor.

7. The process according to claim 4, wherein the non-stirred reactor is a plug-flow reactor.

8. The process according to any one of claims 1 to 7, wherein at least one of the first catalyst and the second catalyst has a reactivity ratio of less than 20, and the reactivity ratio of the catalyst is measured using only the catalyst system in a single 1-Gal reactor at a reactor temperature of at least 150°C, in the presence of 1250 grams of ISOPAR-E, with a mole fraction of ethylene in a solution of 0.709 and 60 g of 1-octene.

9. The process according to any one of claims 1 to 8, wherein the multimodal ethylene copolymer further comprises a low molecular weight fraction of 50% or more based on the total percentage of the multimodal ethylene copolymer, calculated by measuring the area fraction of a molecular weight chromatogram obtained from the absolute molecular weight obtained from low-angle light scattering of less than 500,000 g / mol.

10. The process according to any one of claims 1 to 9, wherein the multimodal ethylene copolymer further comprises a high molecular weight fraction of 10% to 50% based on the total percentage of the multimodal ethylene copolymer, calculated by measuring the area fraction of a molecular weight chromatogram obtained from the absolute molecular weight obtained from low-angle light scattering of more than 500,000 g / mol.

11. The process according to any one of claims 1 to 10, wherein the multimodal ethylene copolymer further comprises a high molecular weight fraction of 20 to 50%, based on the total percentage of the multimodal ethylene copolymer, calculated by measuring the area fraction of a molecular weight chromatogram obtained from the absolute molecular weight obtained from low-angle light scattering of more than 500,000.

12. The process according to any one of claims 1 to 11, wherein the multimodal ethylene copolymer has a density of 0.900 g / cc to 0.940 g / cc as measured in accordance with ASTM D792.

13. The multimodal ethylene copolymer was measured at 2.16 kg and 190°C in accordance with ASTM 1238, exhibiting a melt strength of at least 5 cN and a melt index (I) of at least 0.5 g / 10 min. ２ The process according to any one of claims 1 to 12, comprising:

14. The multimodal ethylene copolymer has a melt strength (MS) that satisfies the following formula, [Math 1] In the equation, x is equal to 15, y is equal to 1, and I ２ The process according to any one of claims 1 to 13, wherein the melt index of the copolymer is measured in accordance with ASTM 1238 at 2.16 kg and 190°C.

15. V ０．１ / V １００ The process according to any one of claims 1 to 14, wherein the value is greater than 10 when determined by dynamic mechanical analysis.

16. The process according to any one of claims 1 to 15, wherein the temperature of the first reactor is 160°C to 200°C.

17. The first catalyst is as follows: 【Chemistry 1】 A process according to any one of claims 1 to 16, selected from one of the following.

18. The second catalyst mentioned above is as follows: 【Chemistry 2】 A process according to any one of claims 1 to 17, selected from one of the following.

19. The process according to any one of claims 1 to 18, wherein the process further comprises a third catalyst system.

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