Polymer blends comprising trimodal ethylene-based polymer and PCR

Abstract

The polymer blend may comprise a post consumer recycle (PCR) ethylene-based polymer; and a trimodal ethylene-based polymer, the trimodal ethylene-based polymer comprising a first polymer fraction, a second polymer fraction, and a third polymer fraction, wherein the first polymer fraction, the second polymer fraction, and the third polymer fraction each comprise the polymerization reaction product of an ethylene monomer and optionally a C3-C14 alpha-olefin comonomer, provided that at least one of the first polymer fraction, the second polymer fraction, and the third polymer fraction comprises the polymerization reaction product of an ethylene monomer, a polyene comonomer, and optionally a C3-C14 alpha-olefin comonomer.

Description

[0001] Cross-reference to related applications

[0002] This application claims the benefit of U.S. Provisional Application Serial No. 63 / 579,100, filed on August 28, 2023, the contents of which are incorporated herein by reference in their entirety. Technical Field

[0003] The implementation scheme generally relates to multi-peaked ethylene-based polymers, and particularly to polymer blends comprising tri-peaked ethylene-based polymers and post-consumption recycling (PCR) ethylene-based polymers. Background Technology

[0004] Due to the contamination and excessive thermal history associated with recycling processes, PCR membranes exhibit poorer durability properties compared to most virgin polyethylene membranes. These poorer durability properties make it challenging to upgrade PCR polymers to meaningful PCR concentrations for high-end membrane applications. Instrumented dart impact (IDI) resistance is one durability property in which PCR membranes lag behind virgin membranes.

[0005] Therefore, membranes that meet the desired durability standards (including IDI) are needed while still containing a meaningful amount of PCR to improve sustainability. Summary of the Invention

[0006] The embodiments of this disclosure meet this need by providing polymer blends comprising a PCR-based ethylene polymer and a tri-peaked ethylene-based polymer. Without being theoretically limited, introducing the tri-peaked ethylene-based polymer allows the membrane to contain a meaningful amount of the PCR-based ethylene polymer while still maintaining the desired robust properties (such as instrumented dart impact resistance).

[0007] According to one or more embodiments, a polymer blend comprising a PCR-based ethylene polymer and a trimodal ethylene-based polymer is provided. The trimodal ethylene-based polymer comprises a first polymer fraction, a second polymer fraction, and a third polymer fraction. Each of the first, second, and third polymer fractions comprises an ethylene monomer and optional C3-C... 14 The polymerization product of an α-olefin comonomer, wherein at least one of the first, second, and third polymer fractions comprises an ethylene monomer, a polyene comonomer, and optionally C3-C4. 14 The polymerization product of α-olefin comonomers.

[0008] These and other implementations are described in more detail in the following detailed description. Detailed Implementation

[0009] definition

[0010] The term "polymer" refers to a polymeric compound prepared by polymerizing monomers, whether of the same or different types. Therefore, the general term polymer encompasses the term "homopolymer," which is typically used to refer to a polymer prepared from only one type of monomer; and "copolymer," which refers to a polymer prepared from two or more different types of monomers.

[0011] "Polyethylene" or "ethylene-based polymer" should mean a polymer comprising more than 50% by weight of units derived from ethylene monomers. This includes polyethylene homopolymers or copolymers (meaning units derived from two or more monomer types). Common forms of polyethylene known in the art include low-density polyethylene (LDPE); linear low-density polyethylene (LLDPE); ultra-low-density polyethylene (ULDPE); very low-density polyethylene (VLDPE); single-point catalytic linear low-density polyethylene, including both linear and substantially linear low-density resins (m-LLDPE); medium-density polyethylene (MDPE); and high-density polyethylene (HDPE).

[0012] The term "LDPE" can also be referred to as "high-pressure ethylene polymer" or "highly branched polyethylene," and is defined as meaning that the polymer is partially or fully homopolymerized or copolymerized in an autoclave or tubular reactor at pressures above 14,500 psi (100 MPa) using a free radical initiator, such as a peroxide (see, for example, U.S. Patent No. 4,599,392, which is incorporated herein by reference in its entirety)). LDPE resin typically has a viscosity of 0.916 g / cm³. 3 Up to 0.930 g / cm 3 The density within the range.

[0013] The term "LLDPE" includes: resins produced using Ziegler-Natta catalyst systems and resins produced using single-site catalysts, including but not limited to bismetallocene catalysts (sometimes referred to as "m-LLDPE"), phosphine imides, and geometry-restricted catalysts; and resins produced using post-metallocene molecular catalysts, including but not limited to bis(biphenylphenoxy) catalysts (also known as polyaryloxy ether catalysts). LLDPE includes linear, substantially linear, or heterogeneous ethylene-based copolymers. LLDPE contains fewer long-chain branchings than LDPE and comprises: substantially linear ethylene polymers, which are further defined in U.S. Patent Nos. 5,272,236, 5,278,272, 5,582,923, and 5,733,155, each of which is incorporated herein by reference in its entirety; homogeneous branched linear ethylene polymer compositions, such as those described in U.S. Patent No. 3,645,992, which is incorporated herein by reference in its entirety; heterogeneous branched ethylene polymers, such as those prepared according to the process disclosed in U.S. Patent No. 4,076,698, which is incorporated herein by reference in its entirety; and blends thereof (such as those disclosed in U.S. Patent Nos. 3,914,342 and 5,854,045, which are incorporated herein by reference in their entirety). LLDPE resins can be prepared by gas-phase, solution-phase, or slurry polymerization or any combination thereof, using any type of reactor or reactor configuration known in the art.

[0014] The terms “blend,” “polymer blend,” and similar terms mean a composition of two or more polymers. Such blends may or may not be miscible. Such blends may or may not be phase-separated. Such blends may or may not contain one or more domain configurations, as determined by transmission electron spectroscopy, light scattering, X-ray scattering, and any other methods known in the art. Blends are not laminates, but one or more layers of a laminate may contain blends. Such blends can be prepared as dry blends, in-situ formed (e.g., in a reactor), melt blends, or using other techniques known to those skilled in the art.

[0015] "Multilayer structure" or "multilayer membrane" refers to any structure having more than one layer. For example, a multilayer structure (e.g., a membrane) can have two, three, four, five, six, seven, or more layers. A multilayer structure can be described as having layers represented by letters. For example, a three-layer structure designated A / B / C can have a core layer (B) and two outer layers (A) and (C).

[0016] As used herein, "multimodal" refers to a polymer produced by multiple polymer fractions, each produced by a different catalyst in a different reaction environment. Multimodal polymers can include bimodal polymers with two polymer fractions, trimodal ethylene-based polymers with three polymer fractions, or polymers with more than three polymer fractions.

[0017] As used herein, the term "polyene" refers to a comonomer having at least two double bonds. Polyene encompasses "dienes," which are comonomers having two double bonds.

[0018] The term "defect" refers to a visible defect in the bulk polymer or membrane. Defects can be caused by foreign contamination or polymer degradation. When present, defects reduce the transparency of the membrane.

[0019] The term "long-chain branching" refers to a branch with more than 100 carbon atoms. A "branch" refers to a portion of a polymer that extends from a tertiary or quaternary carbon atom. When a branch extends from a tertiary carbon atom, two other branches exist, which together can be a polymer chain from which the first branch extends. A polymer chain is a linear segment of a polymer, or more specifically a copolymer, which is optionally connected at its ends by branching junctions. For example, a tetrafunctional branching junction connects the ends of four polymer chains, as opposed to a trifunctional branching junction connects the ends of three polymer chains.

[0020] The terms “comprising,” “including,” “having,” and their derivatives are not intended to exclude the presence of any additional components, steps, or procedures, whether or not such components, steps, or procedures are specifically disclosed. For the avoidance of any doubt, unless otherwise stated, all compositions claimed using the term “comprising” may include any additional additives, auxiliaries, or compounds, whether in polymeric or other forms. In contrast, the term “consistently composed of” excludes any other components, steps, or procedures from any subsequently listed scope, except those that are not essential for operability. The term “composed of” excludes any components, steps, or procedures not specifically described or listed.

[0021] "Recycled polymer" refers to a polymer that is incorporated into a product and subsequently remelted to form a recycled polymer. The term "recycled polymer" specifically refers to a mechanically recycled polymer, where the polymer is melted and re-incorporated into a new product. "Recycled polymer" does not include chemically recycled polymers, where the polymer is broken down into constituent monomers and incorporated into a new virgin polymer. The term "recycled polymer" encompasses both pre-consumer recycled polymers and post-consumer recycled polymers. Recycled polymers are defined in ISO 14021 7.8.1.1.

[0022] The terms "pre-consumer recycled polymer" and "post-industrial recycled polymer" refer to polymers including blends of polymers recovered from pre-consumer materials as defined by ISO 14021. Therefore, the general term "pre-consumer recycled polymer" includes blends of polymers recovered from materials transferred from waste streams during the manufacturing process. The general term "pre-consumer recycled polymer" does not include the reuse of materials generated in the process and capable of being recovered in the same process in which they are generated, such as reprocessing, regrinding, or waste. Pre-consumer recycled polymers are defined in ISO 14021 7.8.1.1.

[0023] As used herein, the term "post-consumer recycled" (or "PCR") refers to polymeric materials that include materials previously used in consumer or industrial applications (i.e., pre-consumer recycled polymers and post-industrial recycled polymers). PCRs are typically collected from recycling programs and recycling plants. Ethylene-based polymers in PCRs may include one or more ethylene-based polymers, such as LDPE, LLDPE, HDPE, or polyethylene. PCRs may contain one or more contaminants. Contaminants may be a result of the polymeric material's use prior to reuse. For example, contaminants may include paper, ink, food scraps, or other recycled materials other than polymers that can be generated from the recycling process. PCRs differ from virgin polymeric materials. Virgin polymeric materials, such as virgin polyethylene resins, do not include materials previously used in consumer or industrial applications. Virgin polymeric materials have not undergone, or have not otherwise undergone, a heating or molding process after the initial polymer manufacturing process. PCR resins have different physical, chemical, and flow properties compared to virgin polymeric resins, which in turn may present challenges in incorporating PCRs into commercial-use formulations. Post-consumer resins are defined in ISO 14021 7.8.1.1.

[0024] polymer blends

[0025] Embodiments of this disclosure relate to polymer blends comprising a post-consumption recycling (PCR) ethylene-based polymer and a trimodal ethylene-based polymer. In an embodiment, based on the total weight of the polymer blend, the polymer blend may contain at least 80% by weight, such as at least 90% by weight, at least 95% by weight, at least 99% by weight, or even at least 99.9% by weight of a combined weight of the PCR-based ethylene polymer and the trimodal ethylene-based polymer.

[0026] The polymer blend may contain 20% to 50% by weight of a PCR-based ethylene polymer. In an embodiment, based on the total weight of the polymer blend, the polymer blend may contain 20% to 45% by weight, 20% to 40% by weight, 30% to 50% by weight, 35% to 50% by weight, 40% to 50% by weight, or any subset thereof of a PCR-based ethylene polymer. The remaining portion of the PCR-based ethylene polymer may contain a trimodal ethylene-based polymer.

[0027] PCR-based ethylene polymers

[0028] Based on the total weight of the PCR-based ethylene polymer, the PCR-based ethylene polymer may include at least 51% by weight of post-consumer material, such as at least 75% by weight, at least 80% by weight, at least 85% by weight, at least 90% by weight, at least 95% by weight, or even at least 99% by weight of post-consumer material.

[0029] The PCR-based ethylene polymer may include LDPE, HDPE, LLDPE, or blends thereof. In an embodiment, based on the total weight of the PCR-based ethylene polymer, the PCR-based ethylene polymer resin comprises at least 50% by weight, at least 75% by weight, at least 85% by weight, at least 90% by weight, at least 95% by weight, or even at least 99% by weight of LDPE, HDPE, LLDPE, or blends thereof.

[0030] The PCR-based ethylene polymer may have a density of 0.900 g / cc to 0.930 g / cc. In embodiments, the PCR-based ethylene polymer may have densities of 0.900 g / cc to 0.925 g / cc, 0.900 g / cc to 0.920 g / cc, 0.900 g / cc to 0.915 g / cc, 0.900 g / cc to 0.910 g / cc, 0.905 g / cc to 0.930 g / cc, 0.910 g / cc to 0.930 g / cc, 0.915 g / cc to 0.930 g / cc, 0.920 g / cc to 0.930 g / cc, 0.905 g / cc to 0.925 g / cc, 0.910 g / cc to 0.920 g / cc, or any subset thereof.

[0031] The PCR-based ethylene polymer may have a melt index (I2) of 0.5 dg / min to 3 dg / min. In embodiments, the PCR-based ethylene polymer may have a melt index (I2) of 0.5 dg / min to 2.5 dg / min, 0.5 dg / min to 2.0 dg / min, 0.5 dg / min to 1.5 dg / min, 0.5 dg / min to 1.0 dg / min, 1 dg / min to 3 dg / min, 1.5 dg / min to 3 dg / min, 2 dg / min to 3 dg / min, 2.5 dg / min to 3 dg / min, 1 dg / min to 2.5 dg / min, or any subset thereof.

[0032] Trimodal ethylene-based polymers

[0033] The polymer blends comprised a trimodal ethylene-based polymer. Surprisingly, it has been found that a combination of the trimodal ethylene-based polymer and the PCR-based ethylene polymer improves instrumented dart impact (IDI) resistance at a given PCR concentration.

[0034] The trimodal ethylene-based polymer comprises a first polymer fraction, a second polymer fraction, and a third polymer fraction. Each of the first, second, and third polymer fractions comprises an ethylene monomer and optional C3-C... 14 The polymerization product of an α-olefin comonomer, wherein at least one of the first, second, and third polymer fractions comprises an ethylene monomer, a polyene comonomer, and optionally C3-C4. 14 The polymerization product of α-olefin comonomers.

[0035] In one or more embodiments, the polyene may include acyclic non-conjugated dienes. Acyclic non-conjugated dienes may include one or more of the following: 1,4-pentadiene, 1,5-hexadiene, 1,6-heptadiene, 1,7-octadiene, 1,8-nonadiene, 1,9-decadiene, 1,10-undecadiene, 1,11-dodecadiene, dimethyldivinylsilane, dimethyldiallylsilane, and dimethylallylvinylsilane. The polyene may exclude cyclic or bicyclic polyenes, such as norbornene-based compounds, because these cyclic or bicyclic polyenes cannot be effectively incorporated into the polymer chain to produce long-chain branching.

[0036] C3-C 14 The α-olefin comonomer may include one or more of 1-propylene, 1-butene, 1-hexene, 1-octene, or combinations thereof.

[0037] As described above, the trimodal ethylene-based polymer of the present invention exhibits excellent processability, which can be quantified in part by its melt strength. As further noted above, this processability and melt strength are attributed to the long-chain branching present in the trimodal ethylene-based polymer. In one or more embodiments, the trimodal ethylene-based polymer can have a melt strength (MS) of 4.0 cN to 25.0 cN, where MS is the melt strength in cN (Rheotens apparatus, 190°C, 2.4 mm / s). 2 The distance from the die exit to the wheel center is 120mm, and the extrusion rate is 38.2s. -1 The capillary mold has a length of 30 mm, a diameter of 2 mm, and an entry angle of 180°. In another embodiment, the melt strength (MS) is 4.0 cN to 20.0 cN, 4.0 cN to 15.0 cN, 8.0 cN to 15.0 cN, or 9.0 cN to 14.0 cN.

[0038] Furthermore, the trimodal ethylene-based polymers can have rheological ratios (V) ranging from 4.0 to 12.0. 0.1 / V 100 V 0.1 It is the viscosity of a trimodal ethylene-based polymer at 190°C and an angular frequency of 0.1 radians / second, and V 100 It is the viscosity of the trimodal ethylene-based polymer at 190°C and an angular frequency of 100 radians / second. In another embodiment, the rheological ratio V 0.1 / V 100 The ratio is 4.0 to 8.0 or 4.0 to 6.5. Not limited by theory, the rheological ratio indicates shear thinning, and increased long-chain branching is associated with increased shear thinning. However, in the case of this invention, for example, shear thinning can be controlled in a trimodal ethylene-based polymer by generating one or more fractions other than long-chain branching in the trimodal ethylene-based polymer.

[0039] Trimodal ethylene-based polymers may have a melt index (I2) of 0.3 dg / min to 3 dg / min, such as 0.3 dg / min to 2 dg / min, 0.3 dg / min to 1 dg / min, 0.5 dg / min to 3 dg / min, 0.5 dg / min to 2 dg / min, 0.5 dg / min to 1.0 dg / min, or 0.7 dg / min to 0.9 dg / min, where I2 is measured according to ASTM D1238 (2.16 kg / 190 °C). Trimodal ethylene-based polymers may have an I2 of 5.0 to 15.0 or 5.0 to 10.0. 10 / I2 ratio.

[0040] In one or more embodiments, the trimodal ethylene-based polymer has a density of 0.910 g / cc to 0.930 g / cc, such as 0.910 g / cc to 0.925 g / cc, 0.910 g / cc to 0.920 g / cc, or 0.912 g / cc to 0.920 g / cc.

[0041] In one or more embodiments, as measured by conventional gel permeation chromatography, the trimodal ethylene-based polymer has a molecular weight distribution (MWD) of 3.0 to 5.0, where MWD is defined as Mw / Mn, where Mw is the weight-average molecular weight and Mn is the number-average molecular weight. Furthermore, the trimodal ethylene-based polymer has an Mn of 20.0 kg / mol to 35.0 kg / mol, or 25.0 kg / mol to 35.0 kg / mol. Additionally, the trimodal ethylene-based polymer has an Mw of 100.0 kg / mol to 130.0 kg / mol, or 105.0 kg / mol to 125.0 kg / mol.

[0042] Preparation of trimodal ethylene-based polymers

[0043] Various methods and processing parameters are considered suitable for producing the multimodal and trimodal ethylene-based polymers of this disclosure. In one or more embodiments, a method for producing multimodal ethylene-based polymers (e.g., trimodal ethylene-based polymers) in a reactor system includes a first reactor and a second reactor. The method includes, in the first reactor, reacting ethylene, one or more (C3-C4) catalysts in the presence of a multi-chain catalyst and at least one single-chain catalyst. 14 α-olefin monomers and at least one polyene are polymerized to produce a polyethylene product in a first reactor comprising long-chain branching. The multi-chain catalyst contains multiple polymerization sites, and the long-chain branching occurs during polymerization by concertedly linking two polymer chains of the multi-chain catalyst to the polyene. In a second reactor, ethylene and one or more (C3-C4) polymers are reacted. 14 α-olefin monomers are polymerized in the absence of an initial polyene feed and in the presence of at least one single-chain catalyst to produce polyethylene products in a second reactor. The trimodal ethylene-based polymer comprises polyethylene products from both the first and second reactors.

[0044] The anticipated polymerization reaction may involve solution polymerization, slurry polymerization, or gas-phase polymerization. In specific embodiments, solution polymerization takes place in a first reactor, a second reactor, or both. The first and second reactors may be connected in parallel or in series. Such solution polymerization processes include the use of one or more conventional reactors, such as loop reactors, isothermal reactors, adiabatic reactors, fluidized bed gas-phase reactors, stirred tank reactors, or batch reactors, connected in parallel, in series, or any combination thereof.

[0045] Exemplary solvents used in solution polymerization methods may include, but are not limited to, isoparaffins. For example, such solvents may be named ISOPAR. ™ Purchased from ExxonMobil Chemical by E-commerce platform.

[0046] As described above, one or more single-chain catalysts may be present in the first reactor and the second reactor. In one embodiment, both the first reactor and the single-chain catalyst may contain one type of single-chain catalyst.

[0047] As used herein, a “single-chain catalyst” is a polymerization catalyst having an active polymerization site and / or a reactive metal center and an active polymer chain at that site. Various single-chain catalysts are considered suitable. These may include bis(metallocene) catalysts, phosphine imides, geometry-defined catalysts, post-metallocene catalysts, and single-site molecular catalysts, including but not limited to bis(biphenylphenoxy) catalysts (also known as polyaryloxy ether catalysts).

[0048] In one embodiment, the single-chain catalyst in the first reactor, the second reactor, or both comprises a bis(biphenylphenoxy) catalyst. According to some embodiments, the bis(biphenylphenoxy) catalyst has a structure according to formula (I):

[0049]

[0050] In formula (I), M is a metal selected from titanium, zirconium, or hafnium, in an oxidation state of +2, +3, or +4. (X) n The subscript n is 0, 1, or 2. When the subscript n is 1, X is a monodentate or bidentate ligand, and when the subscript n is 2, each X is selected from monodentate ligands. Each Z is independently selected from -O-, -S-, -N(R) N - or - P(R) P )-;R 1 and R 16 Independently select the group consisting of the following items: –H, (C1-C) 40 ) hydrocarbon group, (C1-C 40 ) heterohydrocarbon group, −Si(R C )3、−Ge(R C )3、−P(RP )2、−N(R N )2、−OR C 、−SR C ,-NO2,-CN,-CF3,R C S(O)−、R C S(O)2−、−N=C(R C )2、R C C(O)O−、R C OC(O)−、R C C(O)N(R)−、(R C )2NC(O)−, halogens, free radicals having formula (II), free radicals having formula (III), and free radicals having formula (IV):

[0051]

[0052] In equations (II), (III), and (IV), R 31–35 R 41–48 and R 51–59 Each of them is independently selected from –H, (C1-C 40 ) hydrocarbon group, (C1-C 40 ) heterohydrocarbon group, −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 C )2NC(O)− or halogen, condition R 1 Or R 16 At least one of them is a group having formula (II), a group having formula (III), or a group having formula (IV).

[0053] In one or more embodiments, each X may be a monodentate ligand, which, independent of any other ligand X, is halogenated and unsubstituted (C1−C1−C2 ... 20 ) hydrocarbon group, unsubstituted (C1−C 20 ) hydrocarbon group C(O)O- or R K R L N-, where RK and R L Each of them is independently unsubstituted (C1-C) 20 ) hydrocarbon group.

[0054] Additional details and examples of bis(biphenylphenoxy) catalysts are provided in PCT publications WO2011 / 146291, WO2018 / 183056, WO2019 / 190925 and U.S. Patent 7060848B2, which are incorporated herein by reference in their entirety.

[0055] In one embodiment, the single-chain catalyst in the first reactor, the second reactor, or both may comprise a phosphonium imide catalyst. The phosphonium imide precatalyst may have the structure of formula (V):

[0056]

[0057] In equation (V), each Q is independently selected from (C1−C) 50 ) hydrocarbon group, (C1−C 50 heteroalkyl groups, -CH2Si(R) C ) 3-Q (OR C ) Q 、−Si(R C ) 3-J (OR C ) J -OSi(R) C ) 3-J (OR C ) J 、−CH2Ge(R C ) 3-J (OR C ) J 、−Ge(R C ) 3-J (OR C ) J 、−P(R C ) 2-W (OR C ) W 、−P(O)(R C ) 2-W (OR C ) W 、−N(R C )2、−NH(R C ),−N(Si(R) C )3)2、−NR C Si(R C )3、−NHSi(R C 3. −OR C 、−SRC ,-NO2,-CN,-CF3,-OCF3,-S(O)R C -S(O)2R C -OS(O)2R C -N=C(R) C )2、−N=CH(R C -N=CH2, -N=P(R) C ) 3、 −OC(O)R C -C(O)OR C 、−N(R C )C(O)R C 、−N(R C )C(O)H、−NHC(O)R C 、−C(O)N(R C )2、−C(O)NHR C 、−C(O)NH2、halogen、B(R Y 4. Al(R) Y )4 or Ga(R Y )4 or monodentate ligands of hydrogen, wherein each R C Independently for (C1−C) 30 ) hydrocarbon group or (C1−C 30 ( ) heterohydrocarbon groups, and each J is 0, 1, 2 or 3, and each W is 0, 1 or 2; each R Y It is -H, (C1−C 30 A hydrocarbon group or halogen atom, wherein two X ligands can be linked to form a metal heterocycle.

[0058] In formula (V), each Y is an independent Lewis base; optionally, Q and Y can be linked to form a ring. Each subscript m is 1 and 2; and each subscript n is 0, 1, and 2. The metal-ligand complex is electrically neutral overall.

[0059] In formula (V), M2 is titanium, zirconium, or hafnium; R 60 R 61 R 62 R 63 and R 64 Independently for (C1-C 50 ) hydrocarbon group, (C1-C 50 ) heterohydrocarbon group, wherein R 61 R 62 R 63 and R 64 Any of the elements in R can be optionally connected to form a ring structure; 65 R 66 and R 67 Independently for (C1-C 20) hydrocarbon group, (C1-C 20 (C6-C) heterohydrocarbon group, (C6-C) 30 )Aryl, (C5-C 30 ) heteroaryl, of which R 65 R 66 and R 67 The two can be arbitrarily connected to form a loop.

[0060] In various implementation schemes, in equation (V), (A) R 60 and R 61 Connect and form a loop, and optionally be connected by one or more R S Replace; or (B) R 52 and R 63 Connect and form a loop, and optionally be connected by one or more R S Substitution; or (C) both (A) and (B). Therefore, when (A), (B), or (C) occurs, the cyclopentadienyl group of formula (V) has a structure selected from the group consisting of:

[0061]

[0062] As described above, multi-chain catalysts produce polymer fractions with long-chain branching. A multi-chain catalyst is a metal-ligand catalyst having at least two polymer chains that promotes the growth of at least two separate polymer chains. Suitable multi-chain catalysts and their mechanisms of action are described in PCT publications WO2020 / 069364, WO2020 / 205585 and WO2021195502A1, which are incorporated herein by reference in their entirety and are briefly summarized herein. At high levels, long-chain branched fractions are produced by adding polyenes, particularly acyclic, non-conjugated dienes, in the presence of a multi-chain catalyst. The polyene is added to the polymer chain in a manner similar to that of an α-olefin, but leaving a side-mounted vinyl group that can be inserted a second time into the polymer chain to produce long-chain branching. As described above, the multi-chain catalyst has at least two independently propagating polymer chains. One olefin in the polyene is incorporated into one polymer chain, and it is believed that a second olefin in the polyene is then rapidly incorporated into a second polymer chain due to the close proximity of the growth sites, thus forming a bridge or ladder. This continuous addition of dienes is called "co-addition" of dienes, as opposed to catalysts without two proximal chains. In this process, diene addition results in a certain concentration of vinyl-containing polymers in the reactor, which then react at subsequent times. Co-addition of polyenes is known as a "ladder" mechanism. The term "ladder" refers to the process where, once a diene is incorporated into two separate polymer chains, the chains are linked together. The first and second polymer chains continue to grow until the polymer is released from the catalyst, the catalyst mold, or another diene is added.

[0063] The embodiments of this disclosure utilize minimal multi-chain and single-chain catalysts in the first reactor. Unbound by theory, the single-chain catalyst will polymerize ethylene and optionally α-olefin comonomers but will not produce a perceptible amount of long-chain branching with the polyene, specifically because the single-chain catalyst does not produce two closely adjacent polymer chains incorporating the polyene. Therefore, the single-chain catalyst will produce a polymer fraction substantially free of long-chain branching, while the multi-chain catalyst produces a long-chain branched polymer fraction in the same reactor without gel formation and reactor fouling. Thus, the polyethylene product from the first reactor comprises a first fraction with long-chain branching and a second fraction substantially free of long-chain branching. As used herein, “substantially free of long-chain branching” means less than 0.01 long-chain branches per 1000 carbon atoms (LCB / 1000C) as measured by NMR. In the following examples, the first reactor is referred to as a high-density reactor because the polyethylene product from the first reactor can have a density greater than 0.930 g / cc and a melt index (I2) greater than 3 dg / min. In one or more embodiments, the trimodal ethylene-based polymer comprises 35% to 55% by weight of a first reactor polyethylene product comprising a first fraction and a second fraction.

[0064] In one or more embodiments, the first fraction, i.e. the long-chain branched fraction, may account for about 2% to 10% by weight of the multi-peaked ethylene-based polymer (e.g., the tri-peaked ethylene-based polymer).

[0065] The second reactor, excluding the initial polyene feed and also excluding the multi-chain catalyst, produces a second reactor polyethylene product that is also substantially free of long-chain branching. In this case, the single-chain catalyst in the second reactor will polymerize ethylene and optionally α-olefin comonomers. In one or more embodiments, the trimodal ethylene-based polymer comprises 45% to 65% by weight of the second reactor polyethylene product, which contains at least a third polymer fraction. In the following examples, the second reactor is referred to as a low-density reactor because the second reactor polyethylene product can have a density of less than 0.910 g / cc, a melt index (I2) of less than 0.8 dg / min, and a MWD of less than 3.0.

[0066] membrane

[0067] Additional embodiments of this disclosure relate to membranes comprising these polymer blends. The membrane may comprise a single-layer membrane or a multilayer membrane. The membranes of this disclosure may have a variety of thicknesses. The thickness of the membrane may depend on many factors, including, for example, the number of layers in the membrane, the composition of the layers in a multilayer membrane, the desired properties of the membrane, the desired end-use application of the membrane, the membrane manufacturing process, etc. In embodiments, the membrane may have a thickness of 0.5 mil to 5 mil, 1 mil to 4 mil, 1 mil to 3 mil, or 1.5 mil to 2.5 mil.

[0068] Various methods are considered for producing the films of this disclosure. In one or more embodiments, the method of manufacturing the film may include cast film extrusion or blown film extrusion.

[0069] additive

[0070] It should be understood that the polymer blends described above, or the films prepared therefrom, may also contain one or more additives as known to those skilled in the art, such as plasticizers, stabilizers (including viscosity stabilizers and hydrolytic stabilizers), primary and secondary antioxidants, ultraviolet absorbers, antistatic agents, dyes, pigments or other colorants, inorganic fillers, flame retardants, lubricants, reinforcing agents (such as glass fibers and sheets), synthetic (e.g., aramid) fibers or pulp, foaming or bubbling agents, processing aids, slip additives, antiblocking agents (such as silica or talc), release agents, tackifying resins, or combinations of two or more of these. Inorganic fillers (such as calcium carbonate) may also be incorporated into the film. In the embodiments, based on the total polymer weight of the blend, the polymer blend may contain 0% to 40% by weight, such as 0% to 15% by weight, 0% to 10% by weight, 0% to 5% by weight, 0.01% to 40% by weight, 0.01% to 15% by weight, 0.01% to 10% by weight, 0.01% to 5% by weight, 0.1% to 40% by weight, 0.1% to 15% by weight, 0.1% to 10% by weight, 0.1% to 5% by weight, 1% to 40% by weight, 1% to 15% by weight, 1% to 10% by weight, 1% to 5% by weight, or any subset thereof, of one or more additives.

[0071] Products

[0072] Embodiments of this disclosure also relate to articles formed from the films of this disclosure, such as packaging. The films of this disclosure are particularly useful in articles requiring good tear strength and dart strength. Examples of such articles may include flexible packaging, pouches, stand-up pouches, and pre-made packaging or pouches. Various methods for producing articles from the embodiments of the films disclosed herein are familiar to those skilled in the art.

[0073] Test methods

[0074] The testing methods include the following:

[0075] Melt index

[0076] The melt indices I2 and I10 of the polymer samples were measured at 190°C and under loads of 2.16 kg and 10 kg, respectively, according to ASTM D-1238 (Method B).

[0077] density

[0078] Samples for density measurement are prepared according to ASTM D4703. According to ASTM D792, Method B involves measuring the sample within one hour of pressing it.

[0079] Instrumented dart impact

[0080] Instrumented dropped dart impact is measured on a 6-inch × 6-inch square sample. The IDI dart test is based on ASTM D7192. The membrane thickness is measured at the center of the sample, and then the membrane is clamped to provide a 3-inch diameter unsupported test area. The membrane is impacted with an impactor at the center of the sample and perpendicular to the plane of the membrane. The impactor consists of a stainless steel plunger rod with a diameter of 12.7 ± 0.13 mm and a hemispherical end of the same diameter, which is polished to a mirror finish. The impactor strikes the membrane sample with sufficient energy at a velocity of 3.3 m / s, such that the velocity reduction at the end of the test is less than 20%. Based on the force-displacement curve, the peak force, peak energy, peak and total displacement, and total energy are reported. Ten repeated measurements are typically performed, and the mean and standard deviation of the results are reported.

[0081] Gel permeation chromatography (SEC) (conventional GPC)

[0082] GPC-SEC (Conventional GPC) measurements were performed according to the test procedures defined in PCT Publication WO2021195502A1.

[0083] Triple detector GPC (TD) (Absolute GPC)

[0084] GPC-TD (Absolute GPC) measurements were performed according to the test procedures defined in PCT Publication WO2021195502A1.

[0085] Dynamic mechanical spectrometry (DMS)

[0086] DMS measurements were performed according to the test procedures defined in PCT Publication WO2019067239A1.

[0087] Melt strength (MS)

[0088] DMS measurements were performed according to the test procedures defined in PCT Publication WO2019067239A1.

[0089] Example

[0090] The following examples illustrate the features of this disclosure, but are not intended to limit the scope of this disclosure. The following experiments analyze the performance of the embodiments of the multilayer films described herein.

[0091] Material

[0092] Trimodal ethylene-based polymers S-1 to S-3 were prepared in a dual-reactor system with a multi-chain catalyst and two single-chain catalysts. Comparative example CS-A is a bimodal ethylene-based polymer prepared in a dual-reactor system with a single-chain catalyst in each reactor but no multi-chain catalyst. The synthesis conditions are described in Table 1.

[0093] All raw materials (monomers and comonomers) and process solvents (narrow-boiling-range, high-purity isoparaffin solvent, Isopar-E) were purified using molecular sieves before being introduced into the reaction environment. Hydrogen was supplied pressurized at a high purity level without further purification. The monomer feed stream to the reactor was pressurized above the reaction pressure using a mechanical compressor. The solvent and comonomer feed streams were pressurized above the reaction pressure via pumps. Each catalyst component was manually diluted in batches with the purified solvent and pressurized above the reaction pressure. All reaction feed streams were measured using mass flow meters and independently controlled by a computer-automated valve control system.

[0094] The reactors used were configured as a parallel dual-reactor system. Each reactor was a non-adiabatic, isothermal, continuously stirred tank reactor (CSTR) filled with liquid and equipped with heat removal. All fresh solvent, monomer, comonomer, diene, hydrogen, and catalyst components could be independently controlled. The total fresh feed stream (solvent, monomer, comonomer, and hydrogen) to each reactor was temperature-controlled by passing the feed stream through a heat exchanger to maintain a single solution phase. The catalyst components were injected directly into the polymerization reactor. The main catalyst component feed was computer-controlled to maintain the monomer conversion of each reactor at a specified target. The co-catalyst component was fed into the main catalyst component based on a calculated specified molar ratio. The reactor feeds are shown in Table 1. The feed stream was continuously mixed with the reactor contents using a reactor agitator. An oil jacket surrounded the reactor to maintain the isothermal reaction environment at the specified temperature.

[0095] In a dual-parallel reactor configuration, the effluent from each polymerization reactor (containing solvent, monomer, comonomer, hydrogen, catalyst components, and polymer) exits the appropriate reactor and is blended. The contents are deactivated by adding isopropanol. At the same reactor outlet location, additional additives are introduced for polymer stabilization (these additives include typical antioxidants suitable for stabilization during extrusion and membrane manufacturing).

[0096] After catalyst deactivation and the addition of additives, the reactor effluent enters a volatilization subsystem where polymers are removed from the non-polymer stream. The polymer melt is granulated and collected. There is no recycling in this method, but recycling is typically achievable.

[0097]

[0098] Cocatalyst A (CoCat A) is bis(hydrogenated tallow alkyl)methylammonium tetra(pentafluorophenyl)borate.

[0099] Cocatalyst B (CoCat B) is MMAO-3A or modified methylaluminoxane.

[0100] The structures of Cat A, Cat B, and Cat C shown in Tables 1A and 1B are provided in Table 2.

[0101]

[0102] The characteristics of CS-A, CS-C and S1-S3 are shown in Table 3.

[0103]

[0104] In addition to the ethylene-based polymers prepared herein, two native ethylene-based polymers (CS-B and CS-C) and a PCR-based ethylene polymer (NATURA PCR-LDPCR-100) were also used in the embodiments of this invention.

[0105] CS-B refers to DOWLEX ™ 2045G, a monophasic LLDPE prepared in a single reactor, has a melt index (I2) of 1 dg / min and a density of 0.92 g / cc, and is commercially available from Dow Inc. Midland MI.

[0106] CS-C refers to a native bimodal ethylene-based polymer prepared in a dual reactor with a melt index (I2) of 0.85 dg / min and a density of 0.918 g / cc, commercially available from Dow Inc. Midland MI.

[0107] AVANGARD ™ NATURA PCR-LDPCR-100, a commercially available PCR (hereinafter referred to as "PCR") from Avangard Innovative LP, Houston, Texas, is a post-consumption recycled ethylene-based polymer with a melt index (I2) of 2 dg / min and a density of 0.914 g / cc.

[0108] Polymer blend production, blown film manufacturing and testing :

[0109] Polymer blends were formed by mixing the native ethylene-based polymer described herein with the PCR-based ethylene polymer in an extruder. The properties of the polymer blends are described in Table 4.

[0110] A single-layer blown film with a target thickness of 2.0 mils was then prepared using a 2" die diameter blown film production line. A gravimetric feeder metered the resin formulation into a Labtech LTE20-32 twin-screw extruder at a rate of 15 lb / h. The resin formulation was then fed from the extruder into a 2" die diameter die with a 1.0 mm gap. The LTE feed throat was set to 193°C, and the remaining barrel, conveyor, and die temperatures were set and maintained at 215°C. To produce the film, the film bubble was inflated to a blow-up ratio of 2.5 using pressurized ambient air, targeting a die circumference of 2.4 lb / hr / in. A double-lip air ring driven by a variable-speed blower was used for all experiments. The freeze line height (FLH) was maintained between 8.9 inches and 10.6 inches. The target film thickness was 2 mils, controlled within ±10% by adjusting the roll speed. The film was then wound into rolls. Prior to testing, the samples were conditioned for at least 40 hours at 23 (+ / -2) °C and 50 (+ / -10) % RH, according to ASTM D618 (Program A).

[0111] Then, as described in the test method, the prepared membrane is subjected to instrumented drop impact (IDI) test.

[0112]

[0113] As can be seen in Table 4, compared with comparative examples CS-A to CS-C, the samples containing three peaks of ethylene-based polymers S-1 to S-3 provided higher IDI for a given PCR content.

[0114] The subject matter of this disclosure has been described in detail and with reference to specific embodiments. It should be noted that the various details disclosed herein should not be construed as implying that such details relate to elements that are essential components of the various embodiments described herein. Furthermore, it will be apparent that modifications and variations may be made without departing from the scope of this disclosure, including but not limited to the embodiments defined in the appended claims.

Claims

1. A polymer blend, said polymer blend comprising: Post-consumption recycling (PCR) ethylene-based polymers; and A trimodal ethylene-based polymer comprising a first polymer fraction, a second polymer fraction, and a third polymer fraction, wherein each of the first, second, and third polymer fractions comprises an ethylene monomer and optional C3-C... 14 The polymerization product of an α-olefin comonomer, provided that at least one of the first polymer fraction, the second polymer fraction, and the third polymer fraction contains an ethylene monomer, a polyene comonomer, and optionally C3-C4. 14 The polymerization product of α-olefin comonomers.

2. The polymer blend of claim 1, wherein the trimodal ethylene-based polymer has a density of 0.910 g / cc to 0.930 g / cc and a melt index (I2) of 0.3 dg / min to 2 dg / min as measured according to ASTM D1238 (190°C, 2.16 kg).

3. The polymer blend according to claim 1 or 2, wherein the trimodal ethylene-based polymer has a melt index (I2) of 0.5 dg / min to 1 dg / min as measured according to ASTM D1238 (190°C, 2.16 kg).

4. The polymer blend according to any one of claims 1 to 3, wherein the PCR-based ethylene polymer has a density of 0.900 g / cc to 0.930 g / cc and a melt index (I2) of 0.5 dg / min to 3 dg / min.

5. The polymer blend according to any one of claims 1 to 4, wherein the polymer blend comprises 20% to 50% by weight of the PCR-based ethylene polymer.

6. The polymer blend according to claim 1 or 5, wherein the polyene comprises an acyclic non-conjugated diene.

7. The polymer blend according to any one of claims 1 to 6, wherein the polyene comonomer comprises 1,4-pentadiene, 1,5-hexadiene, 1,6-heptadiene, 1,7-octadiene, 1,8-nonadiene, 1,9-decadiene, 1,10-undecadiene, 1,11-dodecadiene, dimethyldivinylsilane, dimethyldiallylsilane, and dimethylallylvinylsilane.

8. The polymer blend according to any one of claims 1 to 7, wherein the first fraction has a density of less than 0.925 g / cc, a melt index (I2) of less than 0.5 dg / min, and a MWD of less than 3.

0.

9. The polymer blend according to any one of claims 1 to 8, wherein at least one of the first polymer fraction, the second polymer fraction, and the third polymer fraction is substantially free of long-chain branching.

10. The polymer blend according to any one of claims 1 to 9, wherein the trimodal ethylene-based polymer comprises 45% to 65% by weight of a first fraction and 35% to 55% by weight of a second polymer fraction and the third polymer fraction.

11. A membrane comprising a polymer blend according to any one of claims 1 to 10.

12. The membrane according to claim 11, wherein the membrane is a single-layer membrane or a multilayer membrane.

13. The membrane according to claim 11 or 12, wherein the membrane has an average thickness of 1 mil to 3 mil.

14. The membrane of claim 13, wherein the membrane has an instrumented dart impact (IDI) of at least 0.5 J or preferably at least 2 J.

Images