Polymer blend containing post-consumer recycled (PCR) ethylene polymers

Abstract

The polymer blend consists of post-consumer recycled (PCR) ethylene polymers, ethylene monomers, and C3-C3 polymers. 14 A virgin ethylene-based polymer comprising polymerization reaction products of α-olefin comonomers and polyene comonomers, having a melt strength (MS) greater than 9 cN, where MS is the melt strength in cN units (Rheotens apparatus, 190°C, 2.4 mm / s). 2 120mm from die exit to wheel center, extrusion speed 38.2s -1 The capillary die may have a length of 30 mm, a diameter of 2 mm, and an inlet angle of 180°, and may contain a virgin ethylene-based polymer.

Description

[Technical Field]

[0001] (Cross-reference of related applications) This application claims the benefits of U.S. Provisional Patent Application No. 63 / 579,102, filed on 28 August 2023, the entirety of which is incorporated herein by reference.

[0002] (Field of invention) The embodiments generally relate to polymer blends, and more particularly to polymer blends comprising virgin ethylene polymers and post-consumer recycled (PCR) ethylene polymers. [Background technology]

[0003] PCR films have inferior optical properties compared to most unused polyethylene films due to contamination associated with the recycling process and excessive thermal history. These inferior optical properties are thought to be caused by a higher incidence of external contamination and / or polymer degradation (measured as defect count) in typical PCR films compared to typical virgin polyethylene films. These inferior properties make it difficult to incorporate PCR polymers into high-performance film applications at PCR concentrations meaningful for improving sustainability.

[0004] Therefore, a film is needed that incorporates a significant amount of PCR while still meeting optical standards. [Overview of the project]

[0005] Embodiments of this disclosure satisfy this need by providing a film comprising a blend of a PCR ethylene polymer and a virgin ethylene polymer containing a polyencomonomer. Although not limited by theory, the polyencomonomer promotes long-chain branching, thereby increasing the melt strength of the virgin ethylene polymer (e.g., a melt strength greater than 9 cN). Surprisingly, this increased melt strength has been found to reduce the number of defects when the polymer blend is formed.

[0006] According to one or more embodiments, the polymer blend comprises ethylene monomer, C3-C3 14 A virgin ethylene-based polymer comprising the polymerization reaction product of α-olefin comonomers and polyene comonomers, having a melt strength (MS) greater than 9 cN, where MS is the melt strength in cN units (Rheotens apparatus, 190°C, 2.4 mm / s). 2 120mm from die exit to wheel center, extrusion speed 38.2s -1 The capillary die (30 mm in length, 2 mm in diameter, and 180° inlet angle) may contain a virgin ethylene polymer and a post-consumer recycled (PCR) ethylene polymer.

[0007] These embodiments and other embodiments are described in more detail in the following "Modes for Carrying Out the Invention". [Modes for carrying out the invention]

[0008] definition The term "polymer" refers to polymer compounds prepared by polymerizing monomers, whether of the same or different types. Therefore, the general term polymer encompasses the term "homopolymer," which is commonly used to refer to polymers prepared from only one type of monomer, and "copolymer," which similarly refers to polymers prepared from two or more different monomer types.

[0009] "Polyethylene" or "ethylene-based polymer" means a polymer containing units derived from ethylene monomers at a rate of more than 50% by weight. 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-site catalyst linear low-density polyethylene (m-LLDPE) including both linear low-density resins and substantially linear low-density resins, medium-density polyethylene (MDPE), and high-density polyethylene (HDPE).

[0010] The term "LDPE" is also sometimes referred to as "high-pressure ethylene polymer" or "highly branched polyethylene," and is defined as a polymer that is partially or completely homopolymerized or copolymerized in an autoclave or tubular reactor at a pressure exceeding 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 resins typically have a viscosity of 0.916 g / cm³. 3 ~0.930g / cm 3 It has a density within the range.

[0011] The term "LLDPE" includes resins produced using a Ziegler-Natta catalyst system, as well as resins produced using single-site catalysts including, but not limited to, bismetallocene catalysts (sometimes also referred to as "m-LLDPE"), phosphinimine, and geometrically constrained catalysts, and resins produced using post-metallocene molecular catalysts including, but not limited to, bis(biphenylphenoxy) catalysts (also referred to as polyvalent aryloxyether catalysts). LLDPE includes linear, substantially linear, or heterogeneous ethylene-based copolymers. LLDPE contains fewer long chain branches than LDPE, and includes substantially linear ethylene polymers as 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; uniformly 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; heterogeneously 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, each of which is incorporated herein by reference in its entirety). LLDPE resins can be produced by gas phase, solution phase, or slurry polymerization, or any combination thereof, using any type of reactor or reactor configuration known in the art.

[0012] Terms such as "blend" and "polymer blend" mean a composition of two or more types of polymers. Such a blend may or may not be miscible. Such a blend may or may not be phase-separated. Such a blend may or may not contain one or more domain structures as determined by transmission electron spectroscopy, light scattering, X-ray scattering, and any other method known in the art. A blend is not a laminate, but one or more layers of the laminate may contain the blend. Such a blend can be prepared as a dry blend, and can be formed in situ (for example, in a reactor), as a melt blend, or using other techniques known to those skilled in the art.

[0013] "Multilayer structure" or "multilayer film" means any structure having more than one layer. For example, a multilayer structure (e.g., a film) may have 2, 3, 4, 5, 6, 7, or more layers. A multilayer structure may be described as having layers designated by letters. For example, a three-layer structure designated as A / B / C may have a core layer (B), and two outer layers (A) and (C).

[0014] As used herein, "multimodal" refers to a polymer produced from a plurality of polymer fractions, each polymer fraction being produced by different catalysts in different reaction environments. Multimodal may include a bimodal polymer having two polymer fractions, a trimodal ethylene-based polymer having three polymer fractions, or a polymer having more than three polymer fractions.

[0015] As used herein, the term "polyene" refers to a comonomer having at least two double bonds. Polyene includes "diene", which is a comonomer having two double bonds.

[0016] The term "defect" refers to a visible defect in a bulk polymer or film. Defects may arise from external contamination or degraded polymer. When defects are present, they reduce the transparency of the film.

[0017] The term "long-chain branching" refers to a branch having more than 100 carbon atoms. "Branching" refers to a portion of a polymer extending from a tertiary or quaternary carbon atom. If a branch extends from a tertiary carbon atom, there are two other branches, which collectively may be the polymer strand to which the branch extends. A polymer strand is a linear segment of a polymer, or more specifically, a copolymer, which is optionally joined at its ends by branching junctions. For example, a tetrafunctional branching junction joins the ends of four polymer strands, in contrast to a trifunctional branching junction which joins the ends of three polymer strands.

[0018] The terms “comprising,” “including,” and “having,” and their derivatives, are not intended to exclude the presence of any additional components, processes, or procedures, whether or not they are specifically disclosed. To avoid any doubt, all compositions claimed through the use of the term “comprising” may, unless otherwise stated, include any additional additives, adjuvants, or compounds, whether polymeric or not. In contrast, the term “consisting essentially of” excludes any other components, processes, or procedures from the scope of any subsequent description, except those not essential to operability. The term “consisting of” excludes any components, processes, or procedures that are not specifically described or enumerated.

[0019] "Recycled polymer" refers to a polymer that has been incorporated into a product and subsequently remelted to form a recycled polymer. The term "recycled polymer" refers to a mechanically recycled polymer in which the polymer is melted and reincorporated into a new product. "Recycled polymer" does not include a chemically recycled polymer in which 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.

[0020] The terms “pre-consumer recycled polymer” and “post-industrial recycled polymer” refer to polymers that include blends of polymers recovered from pre-consumer materials, as defined by ISO 14021. Therefore, the collective term “pre-consumer recycled polymer” includes blends of polymers recovered from materials separated from waste streams during the manufacturing process. The collective term “pre-consumer recycled polymer” excludes the reuse of materials that are produced in a process and can be reused within the same process that produced them, such as reprocessing, re-grinding, or scrap. Pre-consumer recycled polymer is defined in ISO 14021 7.8.1.1.

[0021] As used herein, the term “post-consumer recycled” (or “PCR”) refers to polymer materials containing materials previously used in consumer or industrial applications (i.e., pre-consumer recycled polymers and post-industrial recycled polymers). PCRs are typically recovered from recycling programs and recycling plants. PCR ethylene polymers may contain one or more ethylene polymers such as LDPE, LLDPE, HDPE, or polyethylene. PCRs may contain one or more contaminants. Contaminants may be the result of the use of the polymer material before any modifications were made for reuse. For example, contaminants may include paper, ink, food residue, or other recycled materials, in addition to polymers that may result from the recycling process. PCRs are different from virgin polymer materials. Virgin polymer materials (such as virgin polyethylene resin) do not contain materials previously used in consumer or industrial applications. Virgin polymer materials have not undergone or been subjected to heating or molding processes after the initial polymer manufacturing process. The physical, chemical, and flow properties of PCR resins differ from those of unused polymer resins, which can present challenges to incorporating PCR into formulations for commercial use. Post-consumer resins are defined in ISO 14021 7.8.1.1.

[0022] Polymer blend Embodiments of this disclosure relate to polymer blends comprising post-consumer recycled (PCR) ethylene polymers and virgin ethylene polymers. In embodiments, the polymer blend may contain, based on the total weight of the polymer blend, at least 80% by weight, for example, at least 90% by weight, at least 95% by weight, at least 99% by weight, or even at least 99.9% by weight of the combined weight of the PCR ethylene polymers and virgin ethylene polymers.

[0023] The polymer blend may contain 10 to 90% by weight of PCR ethylene polymers. In embodiments, the polymer blend may contain 10 to 85% by weight, 10 to 80% by weight, 20 to 90% by weight, 30 to 90% by weight, 40 to 90% by weight, 50 to 90% by weight, 60 to 90% by weight, 70 to 90% by weight, 35 to 85% by weight, 40 to 80% by weight, 30 to 50% by weight, or any subset thereof of PCR ethylene polymers.

[0024] Virgin ethylene polymer Virgin ethylene polymers consist of ethylene monomers and C3-C3 polymers. 14 It contains polymerization reaction products of α-olefin comonomers and polyene comonomers.

[0025] The virgin ethylene polymer may be monomodal or multimodal. In an embodiment, the virgin ethylene polymer may be monomodal, bimodal, or trimodal.

[0026] Polyene comonomers may include acyclic non-conjugated dienes. In embodiments, the acyclic non-conjugated dienes may include one or more of 1,4-pentadiene, 1,5-hexadiene, 1,6-heptadiene, 1,7-octadiene, 1,8-nonadien, 1,9-decadien, 1,10-undecadien, 1,11-dodecadien, dimethyldivinylsilane, dimethyldiallylsilane, and dimethylallylvinylsilane. Polyenes may not include cyclic or bicyclic polyenes, such as norbornene compounds, because these cyclic or bicyclic polyenes do not effectively incorporate into polymer chains to produce long-chain branching. C3~C 14 The α-olefin comonomer may contain one or more of 1-propylene, 1-butene, 1-hexene, 1-octene, or a combination thereof.

[0027] The virgin ethylene-based polymer may have a melt index (I2), when measured in accordance with ASTM D1238 (190°C, 2.16 Kg), of 0.3 to 3 dg / min, such as 0.3 to 2 dg / min, 0.3 to 1 dg / min, 0.5 to 3 dg / min, 1 to 3 dg / min, 2 to 3 dg / min, 1 to 2 dg / min, or any subrange thereof.

[0028] The virgin ethylene-based polymer may have a density of 0.910 to 0.930 g / cc, such as 0.910 to 0.925 g / cc, 0.910 to 0.920 g / cc, or 0.912 to 0.920 g / cc.

[0029] The virgin ethylene-based polymer may have an average g' greater than 0.860, greater than 0.880, or greater than 0.900. This average g' is an intrinsic viscosity ratio determined by gel permeation chromatography using a triple detector.

[0030] As noted above, the virgin ethylene-based polymer has excellent processability, which can be partially quantified by its melt strength. Further as noted above, the reduction in the number of defects when the blend is incorporated into a film is attributed to higher melt strength in the virgin ethylene-based polymer (e.g., melt strength greater than 9 cN). In one or more embodiments, the virgin ethylene-based polymer can have a melt strength (MS) of at least 9 cN, where MS is melt strength in units of cN (measured on a Rheotens apparatus, at 190°C, at 2.4 mm / s 2 , 120 mm from the die exit to the center of the wheel, an extrusion rate of 38.2 s -1 , a capillary die length of 30 mm, a diameter of 2 mm, and an inflow angle of 180°). In further embodiments, the melt strength (MS) of the virgin ethylene-based polymer is at least 10 cN, at least 12 cN, at least 13 cN, at least 20 cN, 9 cN to 35 cN, 10 cN to 35 cN, 12 cN to 35 cN, 20 cN to 35 cN, or any subrange thereof.

[0031] Methods for producing virgin ethylene-based polymers suitable for use in this polymer blend (including types of monomers, catalysts, and reactors) are disclosed, for example, in U.S. Publications 2022 / 0033547, 2022 / 0227905, and 2023 / 0128663, and U.S. Provisional Patent Application 63 / 510,769, which are incorporated herein by reference in their entirety.

[0032] A monomodal virgin ethylene-based polymer suitable for use in this polymer blend may be produced by a double-chain catalyst, as described in U.S. Publication No. 2022 / 0033547, which is incorporated herein in whole. Multimodal virgin resins (e.g., bimodal and trimodal) can be produced by at least one double-chain catalyst and at least one single-chain catalyst.

[0033] In one or more embodiments, single-chain catalysts may include, but are not limited to, Ziegler-Natta catalysts, chromium catalysts, metallocene catalysts, post-metallocene catalysts, constrained geometry complex (CGC) catalysts, phosphineimine catalysts, or bis(phenylphenoxy) catalysts. Details and examples of CGC catalysts are described in U.S. Patents 5,272,236, 5,278,272, 6,812,289, and International Publication WO93 / 08221, all of which are incorporated herein by reference in their entirety. Details and examples of bis(biphenylphenoxy) catalysts are described in U.S. Patents 6,869,904, 7,030,256, 8,101,696, 8,058,373, and 9,029,487, all of which are incorporated herein by reference in their entirety.

[0034] PCR ethylene polymer The PCR ethylene polymer may contain at least 51% by weight of post-consumer material, based on the total weight of the PCR ethylene polymer, for example, 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.

[0035] The PCR ethylene polymer may include LDPE, HDPE, LLDPE, or a blend thereof. In embodiments, the PCR ethylene polymer resin contains 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 a blend thereof, based on the total weight of the PCR ethylene polymer.

[0036] PCR ethylene polymers may have densities of 0.900 to 0.930 g / cc. In embodiments, PCR ethylene polymers may have densities of 0.900 to 0.925 g / cc, 0.900 to 0.920 g / cc, 0.900 to 0.915 g / cc, 0.900 to 0.910 g / cc, 0.905 to 0.930 g / cc, 0.910 to 0.930 g / cc, 0.915 to 0.930 g / cc, 0.920 to 0.930 g / cc, 0.905 to 0.925 g / cc, 0.910 to 0.920 g / cc, or any subset thereof.

[0037] PCR ethylene polymers may have a melt index (I2) of 0.3 to 3 dg / min. In embodiments, PCR ethylene polymers may have a melt index (I2) of 0.3 to 2.5 dg / min, 0.3 to 2.0 dg / min, 0.3 to 1.5 dg / min, 0.3 to 1.0 dg / min, 0.5 to 3 dg / min, 1 to 3 dg / min, 1.5 to 3 dg / min, 2 to 3 dg / min, 1 to 2.5 dg / min, 1.5 to 2.5 dg / min, or any subset thereof.

[0038] When processed into film, PCR ethylene-based polymers are 24.6 cm 3at least 10 mm per unit volume of film 2 The defect area, for example, 24.6 cm². 3 at least 25 mm per unit of film volume 2 Defect area: 24.6 cm² 3 At least 50 mm per unit of film volume 2 Defect area: 24.6 cm² 3 at least 100 mm per unit of film volume 2 Defect area: 24.6 cm² 3 at least 250 mm per unit of film volume 2 Defect area: 24.6 cm² 3 at least 500 mm per unit of film volume 2 Defect area: 24.6 cm² 3 at least 1000 mm per unit of film volume 2 Defect area: 24.6 cm² 3 At least 1500 mm per unit of film volume 2 Defect area: 24.6 cm² 3 At least 2000 mm per unit of film volume 2 Defect area: 24.6 cm² 3 at least 2500 mm per unit of film volume 2 Defect area: 24.6 cm² 3 10mm per unit of film volume 2 From the defect area, 24.6 cm 3 5000 mm per unit of film volume 2 Up to the defect area, 24.6 cm 3 10mm per unit of film volume 2 From the defect area, 24.6 cm 3 10,000 mm per unit of film volume 2 It may have up to the defect area of, or any subset thereof, the number of GI400 defects.

[0039] Suitable PCR ethylene polymers include AVANGARD® NATURA PCR-LDPCR-100 ("AVANGARD® 100") and AVANGARD® NATURA PCR-LDPCR-150 ("AVANGARD® 150") (PCR is commercially available from Avangard Innovative LP (Houston, Texas)).

[0040] film Additional embodiments of this disclosure relate to films. Films may comprise polymer blends as described herein. In embodiments, films may comprise at least 80% by weight, at least 90% by weight, at least 95% by weight, or at least 99% by weight of polymer blends as described herein. In embodiments, films may substantially contain no other polymer components.

[0041] The film may be a single-layer film or a multilayer film, for example, a film having 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or 11 layers. The films of this disclosure can have a variety of thicknesses. The thickness of the film may depend on a number of factors, including, for example, the number of layers in the film, the composition of the layers in a multilayer film, the desired properties of the film, the desired end use of the film, and the manufacturing process of the film. In embodiments, the film may have a thickness of 0.5 to 5 mils, 1 to 4 mils, 1 to 3 mils, or 1.5 to 2.5 mils.

[0042] The film is GI400 (24.6cm). 3 mm per unit volume of film 2The number of defects may be less than 2000 when measured according to the defect area. In embodiments, the film may have a number of defects less than 1950, less than 1900, less than 1800, less than 1600, less than 1400, less than 1200, less than 1000, less than 950, less than 900, less than 800, less than 700, less than 600, less than 500, less than 400, less than 300, less than 200, less than 100, or even less than 50. In embodiments, the film may have a number of defects less than 2000 when the polymer blend contains at least 40% by weight of a PCR ethylene polymer, for example, at least 80% by weight of a PCR ethylene polymer.

[0043] Various methodologies are contemplated for producing the films of this disclosure. In one or more embodiments, the process for producing the film may include extrusion of a cast film or extrusion of an inflated film.

[0044] additives It should be understood that the above-mentioned PCR ethylene polymers, virgin ethylene polymers, or films produced therefrom may further contain one or more additives known to those skilled in the art, such as plasticizers, stabilizers including viscosity stabilizers, hydrolysis stabilizers, primary and secondary antioxidants, UV absorbers, antistatic agents, dyes, pigments, or other colorants, inorganic fillers, flame retardants, lubricants, reinforcing agents such as glass fibers and flakes, synthetic (e.g., aramid) fibers or pulp, forming agents or foaming agents, processing aids, slip additives, anti-tack agents such as silica or talc, release agents, tackifying resins, or two or more combinations thereof. Inorganic fillers such as calcium carbonate may also be incorporated into the film. In embodiments, the polymer blend may contain 0 to 40% by weight of additives, for example, 0 to 30% by weight, 0 to 20% by weight, 0 to 10% by weight, 1 to 40% by weight, 1 to 30% by weight, 1 to 20% by weight, or 1 to 10% by weight.

[0045] Goods Embodiments of this disclosure also relate to articles such as packages formed from the films of this disclosure. The films of this disclosure are particularly useful in articles where good tear strength and dirt strength are desired. Examples of such articles include flexible packages, pouches, self-standing pouches, and ready-made packages or ready-made pouches. Various methods for manufacturing embodiments of articles from the films disclosed herein will be well known to those skilled in the art.

[0046] Test method GI400 polymer defect count The GI400 polymer defect count is a measure of defects detected in extruded films using optical imaging techniques in accordance with ASTM D7310-20, "Standard Practice for Defect Detection and Rating of Plastic Film Using Optical Sensors." The defect count is measured within a defined range, namely, the ranges of 400–800 μm, 800–1600 μm, and 24.6 cm² with an effective circle diameter of 1600 μm or more. 3 Area of ​​optical defects per film (mm²) 2 This is reported as [value]. This is measured by the Optical Control Systems Film Surface Analyzer FSA100 (OCS FSA100) optical imaging system. The OCS FSA100 optical imaging system consists of an illumination unit, a CCD line scan camera, and a computer with image / data analysis software version 10.4.1.7.

[0047] The OCS FSA100 optical imaging system detects defects that obscure the transmission of light from halogen light sources. The average grayscale was set to 170 with a threshold sensitivity setting of 35%. Furthermore, the gain of the CCD system can be adjusted to compensate for film haze. The imaging system creates a composite region of each defect by adding defect pixels from each subsequent line scan. The system then reports the area of ​​the defects that were within a user-defined size range based on the diameter of a circle with an equivalent area.

[0048] Film production Due to the defect rate, a 2-mil thick blow-molded film was manufactured as follows: A gravimetric feeder fed the resin mixture into a Labtech LTE20-32 twin-screw extruder at a rate of 15 pounds / hour. From the extruder, the resin mixture was transported to a 2-inch diameter die with a 1.0 mm gap. The LTE feed throat was set to 193°C, and the remaining barrel, transport section, and die temperatures were set and maintained at 215°C. Pressurized ambient air inflated the film bubbles to a blow-up ratio of 2.5. A dual-lip air ring driven by a variable-speed blower was used in all experiments. The frost line height (FLH) was maintained between 8.8 and 10.8 inches. The film thickness was targeted at 2 mils and controlled within ±15% by adjusting the nip roller speed. The film was wound onto rolls.

[0049] Melt Index Melt indices I2 and I of polymer samples 10 These were measured at 190°C and under loads of 2.16 kg and 10 kg, respectively, according to ASTM D-1238 (Method B).

[0050] 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.

[0051] Gel Penetration Chromatography (GPC) Size Exclusion Chromatography (SEC) (Conventional GPC)

[0052] GPC-SEC (conventional GPC) measurements were performed according to the test procedures defined in International Publication No. WO2021195502(A1).

[0053] Triple Detector GPC (TD) (Absolute GPC) GPC-TD (absolute GPC) measurements were performed according to the test procedures defined in International Publication No. WO2021195502(A1).

[0054] Dynamic mechanical spectroscopy (DMS) DMS measurements were performed according to the test procedures defined in International Publication No. WO2019067239(A1).

[0055] Melt strength (MS) DMS measurements were performed according to the test procedures defined in International Publication No. WO2019067239(A1). [Examples]

[0056] The following examples illustrate the features of the present disclosure, but are not intended to limit the scope of the present disclosure. The performance of embodiments of the multilayer films described herein was analyzed in the following experiments.

[0057] material: A series of virgin ethylene-based polymers were prepared as follows.

[0058] Bimodal ethylene polymers S-2 to S-6 were produced in a single reactor containing a multi-chain catalyst and a single-chain catalyst. Trimodal ethylene polymer S-1 was produced in a double reactor containing a multi-chain catalyst and two single-chain catalysts. Comparative Examples CS-A to CS-C were trimodal ethylene polymers produced in a double reactor system containing a multi-chain catalyst and two single-chain catalysts. Comparative Example CS-D was a bimodal ethylene polymer produced in a double reactor system containing two single-chain catalysts. Comparative Example CS-E was a bimodal ethylene polymer produced in a single reactor system containing a single-chain catalyst and a multi-chain catalyst.

[0059] Before introducing them into the reaction environment, all raw materials (monomers and comonomers) and process solvent (high-purity isoparaffin 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 also pressurized to a pressure exceeding the reaction pressure using pumps. Individual catalyst components were manually batch diluted with purified solvents and pressurized to a pressure exceeding 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.

[0060] Two different reactor configurations were used: a single-reactor system and a parallel-mode dual-reactor system. Each continuous solution polymerization reactor consisted of a liquid-filled, non-adiabatic, isothermal continuously stirred tank reactor (CSTR) that removed heat. Independent control of all fresh solvents, monomers, comonomers, dienes, hydrogen, and catalyst components was possible. All fresh feed streams to each reactor (solvent, monomers, comonomers, dienes, and hydrogen) were temperature-controlled to maintain a single solution phase by passing the feed streams through a heat exchanger. Catalyst components were injected directly into the polymerization reactor. The supply of the main catalyst component was computer-controlled to maintain monomer conversion in each reactor at a specified target. Co-catalyst components were supplied based on a calculated, specified molar ratio to the main catalyst component. The reactor feeds are shown in Table 1. The feed streams were continuously mixed with the reactor contents using a reactor agitator. The reactors had oil jackets around them, which played a role in maintaining an isothermal reaction environment at a specified temperature.

[0061] In the double series reactor configuration, the effluent from each polymerization reactor (containing solvent, monomer, comonomer, hydrogen, catalyst components, and polymer) was blended after exiting the appropriate reactor. In both the single and double reactor configurations, the contents were deactivated by the addition of isopropanol. Other additives were added at this same reactor outlet location to stabilize the polymer (typical antioxidants suitable for stabilization during extrusion and film processing).

[0062] Following catalyst deactivation and additive addition, the reactor effluent entered a devolving system where the polymer was removed from the non-polymer stream. The isolated polymer molten material was pelletized and collected. Recycling was not performed in this process, but it is generally possible to recycle such materials.

[0063] [Table 1]

[0064] [Table 2]

[0065] Co-catalyst A (CoCat A is bis(talualkyl hydride)methylammonium tetrakis(pentafluorophenyl) borate) Co-catalyst B (CoCat B) is MMAO-3A or modified methylaluminoxane. The structures of Cat A, Cat B, Cat C, and Cat D, as described in Tables 1A and 1B, are provided in Table 2 below.

[0066] [Table 3]

[0067] Details of the generated polymer are shown in Table 3.

[0068] [Table 4]

[0069] [Table 5]

[0070] CS-F refers to DOWLEX® 2045G, a monomodal LLDPE commercially available from Dow Inc. (Midland MI), produced in a single reactor, with a melt index (I2) of 1 dg / min and a density of 0.92 g / cc.

[0071] CS-G refers to a virgin bimodal ethylene polymer produced in a double reactor, commercially available from Dow Inc. (Midland MI), with a melt index (I2) of 0.85 dg / min and a density of 0.918 g / cc.

[0072] AVANGARD® NATURA PCR-LDPCR-100 (hereinafter referred to as "PCR"), a PCR commercially available from Avangard Innovative LP (Houston, Texas), is a post-consumer recycled ethylene polymer with a melt index (I2) of 2 dg / min and a density of 0.914 g / cc. The film of 100% PCR, when determined by the measurement system and inflation film formation specified above, is 24.6 cm². 3 2750 mm per unit of film volume 2 It has a defect area and a GI400 defect count.

[0073] Manufacturing of polymer blends, manufacturing of inflation films, and testing: The polymer blends were formed by mixing the virgin ethylene-based polymers described herein with PCR-based ethylene-based polymers in an extruder. The properties of the polymer blends are shown in Table 4.

[0074] Next, the polymer blend was processed into a single-layer inflation film with a target thickness of 2.0 mil, manufactured using an inflation film line with a 2-inch die diameter. A gravimetric feeder fed the resin compound into a Labtech LTE20-32 twin-screw extruder at a rate of 15 lbs / hour. The resin compound was transported from the extruder to a 2-inch diameter die with a 1.0 mm gap. The LTE feed throat was set to 193°C, and the remaining barrel, transport section, and die temperatures were set and maintained at 215°C. To manufacture the film, a target die circumference of 2.4 lb / hour / in was achieved using pressurized ambient air to inflate the film bubbles to a blow-up ratio of 2.5. A dual-lip air ring driven by a variable-speed blower was used in all experiments. The frost line height (FLH) was maintained at 8.9–10.6 inches. The film thickness was targeted at 2 mil and controlled within ±10% by adjusting the nip roller speed. The film is wound onto a roll. Before testing, the sample is conditioned at 23 (±2) °C and 50 (±10) % RH for a minimum of 40 hours according to ASTM D618 (Procedure A).

[0075] Next, the manufactured films were subjected to a polymer defect count test as described in the test method. The results are shown in Table 4.

[0076] [Table 6]

[0077] As can be seen from Table 4, comparative samples CS-A to CS-G had a substantially larger number of GI400 defects than samples S-1 to S-6, which had a melt strength greater than 9 cN, in both 40% and 80% PCR.

Claims

1. It is a polymer blend, A virgin ethylene polymer, comprising ethylene monomer, C ３ ~C １４ The product comprises a polymerization reaction product of α-olefin comonomers and polyene comonomers, and has a melt strength (MS) greater than 9 cN, where the MS is the melt strength in cN units (Rheotens apparatus, 190°C, 2.4 mm / s). ２ 120 mm from die exit to wheel center, extrusion speed 38.2 s －１ (Capillary die length 30 mm, diameter 2 mm, and inlet angle 180°), virgin ethylene-based polymer, A polymer blend containing post-consumer recycled (PCR) ethylene-based polymers.

2. The PCR ethylene polymer has a density of 0.900 to 0.930 g / cc and a melt index (I) of 0.3 to 33 dg / min. ２ The polymer blend according to claim 1, having )

3. The virgin ethylene polymer has a density of 0.910 to 0.930 g / cc and a melt index (I) of 0.3 to 3 d g / min when measured according to ASTM D1238 (190°C, 2.16 kg). ２ The polymer blend according to claim 1 or 2, having )

4. The polymer blend according to claim 1 or 3, wherein the MS of the virgin ethylene-based polymer is at least 9 cN.

5. The polymer blend according to any one of claims 1 to 4, wherein the polyene comprises an acyclic non-conjugated diene.

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

7. The polymer blend according to any one of claims 1 to 6, wherein the polymer blend comprises 10 to 90% by weight of the PCR ethylene-based polymer.

8. The polymer blend according to any one of claims 1 to 7, wherein the virgin ethylene polymer is monomodal or multimodal.

9. A film comprising the polymer blend according to any one of claims 1 to 8.

10. The film according to claim 9, wherein the film is a single-layer film or a multi-layer film.

11. The film according to claim 9 or 10, wherein the film has an average thickness of 1 to 3 mils.

12. The aforementioned film is GI400 (24.6cm ３ mm per unit volume of film ２ The film according to any one of claims 9 to 11, having a defect count of less than 1,000 when measured according to the defect area.

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