WO2025029615A1 - Multilayer films containing post-consumer recycled (pcr) with higher tear resistance - Google Patents

Abstract

In one aspect, a multilayer film includes a first outer layer, a second outer layer, and at least one core layer positioned between the first outer layer and the second outer layer, where the at least one core layer includes post-consumer recycled (PCR) polyethylene resin having a density of 0.930 to 0.950 g/cc as determined according to ASTM D792, a melt index (I2) of 1.0 to 3.0 dg/min as determined according to ASTM D1238 (2.16 kg, 190 °C), and a molecular weight distribution (MWD=Mw/Mn) of 5 to 12, and the first outer layer and the second outer layer comprise ethylene-based polymer, propylene-based polymer, or combinations thereof.

Description

85477-WO-PCT/DOW 85477 WO MULTILAYER FILMS CONTAINING POST-CONSUMER RECYCLED (PCR) WITH HIGHER TEAR RESISTANCE CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims the benefit of U.S. Provisional Application Serial No. 63/517,027 filed August 1, 2023, the entirety of which is incorporated by referenced herein. TECHNICAL FIELD [0002] Embodiments described herein generally relate to multilayer films and, more specifically, to multilayer films including recycled resins. BACKGROUND [0003] There is a growing trend in the marketplace towards the use of Post-Consumer Recycled (PCR) material in low and high-performance stretch films for unitization purposes, ensuring suitable unit load stability, integrity, safety, and delivering a sustainable solution at the same time. [0004] New challenges arose in the past few years due to new legislation and/or brand- owner commitments to reach a certain content of PCR in their packages for future years. Based on this new market requirement, many companies are working to replace part of virgin resins by post-consumer resins. [0005] Currently, the usage of a suitable PCR in stretch film is limited due to possible contaminants (e.g., cellulosic impurities from labels), low and/or variable mechanical properties of the recycled resins, and degradation that can generate processing inconveniences, such as unstable pressures or breakages on the molten web. [0006] PCRs could also impact the performance of the film since this may reduce the maximum elongation the film can reach (ultimate stretch) and other mechanical properties such as puncture and tear resistance. [0007] As a result, a PCR with minimum contaminants that keeps or even enhances abuse properties, such as tear resistance, is a continual need. BRIEF SUMMARY 85477-WO-PCT/DOW 85477 WO [0008] Embodiments of the present disclosure meet this need for sustainability while maintaining or improving the abuse properties. [0009] In one aspect, a multilayer film includes a first outer layer, a second outer layer, and at least one core layer positioned between the first outer layer and the second outer layer, where the at least one core layer includes post-consumer recycled (PCR) polyethylene resin having a density of 0.930 to 0.950 grams per cubic centimeter (g/cc) as determined according to ASTM D792, a melt index (I₂) of 1.0 to 3.0 decigram per minute (dg/min) as determined according to ASTM D1238 (2.16 kg, 190 °C), and a molecular weight distribution (MWD=Mw/Mn) of 5 to 12, and the first outer layer and the second outer layer comprise ethylene-based polymer, propylene-based polymer, or combinations thereof. [0010] Additional features and advantages will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the embodiments described herein, including the detailed description which follows and the claims. [0011] It is to be understood that both the foregoing general description and the following detailed description describe various embodiments and are intended to provide an overview or framework for understanding the nature and character of the claimed subject matter. BRIEF DESCRIPTION OF THE DRAWING [0012] FIG. 1 illustrates a schematic view of one embodiment of the present multilayer film. DETAILED DESCRIPTION [0013] DEFINITIONS [0014] "Polymer" refers to a polymeric compound prepared by polymerizing monomers, whether of the same or a different type. The term polymer thus embraces the term homopolymer (employed to refer to polymers prepared from only one type of monomer, with the understanding that trace amounts of impurities can be incorporated into the polymer structure), and the term copolymer or interpolymer. Trace amounts of impurities (for example, catalyst residues) may be incorporated into and/or within the polymer. A polymer may be a single polymer or a polymer blend. 85477-WO-PCT/DOW 85477 WO [0015] As used herein, the term “copolymer” means a polymer formed by the polymerization reaction of at least two structurally different monomers. The term “copolymer” is inclusive of terpolymers. For example, ethylene copolymers, such as ethylene-propylene copolymers, include at least two structurally different monomers (e.g., ethylene-propylene copolymer includes copolymerized units of at least ethylene monomer and propylene monomer) and can optionally include additional monomers or functional materials or modifiers, such as acid, acrylate, or anhydride functional groups. Put another way, the copolymers described herein comprise at least two structurally different monomers, and although the copolymers may consist of only two structurally different monomers, they do not necessarily consist of only two structurally different monomers and may include additional monomers or functional materials or modifiers. [0016] "Multilayer film" refers to any structure having more than one layer. For example, the multilayer structure may have five or more layers, such as 6, 7, 89, 10, or 11 layers. In embodiments, the multilayer film may have an odd number of layers, such as 5, 6, 9, or 11 layers. [0017] “Polyethylene” as used herein, refers to "ethylene-based polymer" shall mean polymers comprising greater than 50% by weight of units which have been derived from ethylene monomer. This includes polyethylene homopolymers or copolymers (meaning units derived from two or more comonomers). 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 catalyzed Linear Low Density Polyethylene, including both linear and substantially linear low density resins (m-LLDPE); Medium Density Polyethylene (MDPE); and High Density Polyethylene (HDPE). [0018] "Ethylene-propylene copolymer" refers to ethylene-based polymers with propylene comonomers. The ethylene-propylene copolymers of the present disclosure may comprise a majority (greater than 50 wt.%) of the residues of ethylene monomers, based on the total polymer weight of the ethylene-propylene copolymer. The remainder of the polymer weight of the ethylene-propylene copolymer may comprise the residues of propylene monomers. [0019] "Polypropylene" or “propylene-based polymers” shall mean polymers comprising greater than 50% by weight of units derived from propylene monomer. This includes polypropylene homopolymers or copolymers (meaning units derived from comonomer, such 85477-WO-PCT/DOW 85477 WO as ethylene). Common forms of polypropylene known in the art include homopolymer polypropylene (hPP), random copolymer polypropylene (rcPP), impact copolymer polypropylene (hPP + at least one elastomeric impact modifier) (ICPP) or high impact polypropylene (HIPP), high melt strength polypropylene (HMS-PP), isotactic polypropylene (iPP), syndiotactic polypropylene (sPP), and combinations thereof. [0020] “Residues” refers to the portion of a polymer derived from a specific monomer. [0021] The term “LDPE” may also be referred to as “high pressure ethylene polymer” or “highly branched polyethylene” and is defined to mean that the polymer is partly or entirely homopolymerized or copolymerized in autoclave or tubular reactors at pressures above 14,500 psi (100 MPa) with the use of free-radical initiators, such as peroxides (see for example U.S. Pat. No. 4,599,392, incorporated herein by reference). [0022] The term “LLDPE”, includes resins made using the traditional Ziegler-Natta catalyst systems as well as single-site catalysts such as metallocenes (sometimes referred to as “m- LLDPE”). LLDPEs contain less long chain branching than LDPEs and include the substantially linear ethylene polymers which are further defined in U.S. Pat. No. 5,272,236, U.S. Pat. No. 5,278,272, U.S. Pat. No. 5,582,923 and U.S. Pat. No. 5,733,155; the homogeneously branched linear ethylene polymer compositions such as those in U.S. Pat. No. 3,645,992; the heterogeneously branched ethylene polymers such as those prepared according to the process disclosed in U.S. Pat. No. 4,076,698; and/or blends thereof (such as those disclosed in U.S. Pat. No. 3,914,342 or U.S. Pat. No. 5,854,045). The LLDPE can be made via gas-phase, solution-phase or slurry polymerization or any combination thereof, using any type of reactor or reactor configuration known in the art, including, but not limited to, gas and solution phase reactors. [0023] “Recycled resins” refers to resins, which were incorporated into products and subsequently re-melted to form a recycled resin. The term “recycled resins” refers to mechanically recycled resins, where the resin is melted and reincorporated into a new product. “Recycled resins” does not include chemically recycled resins, where the polymer is broken down into constituent monomers and incorporated into a new virgin polymer. The term “recycled resins” embraces both pre-consumer recycled polymer and post-consumer resin. [0024] The terms “pre-consumer recycled polymer” and “post-industrial recycled polymer” refer to polymers, including blends of polymers, recovered from pre-consumer material, as 85477-WO-PCT/DOW 85477 WO defined by ISO-14021. The generic term pre-consumer recycled polymer thus includes blends of polymers recovered from materials diverted from the waste stream during a manufacturing process. The generic term pre-consumer recycled polymer excludes the reutilization of materials, such as rework, regrind, or scrap, generated in a process and capable of being reclaimed within the same process that generated it. [0025] The term “post-consumer resin” (or “PCR”), as used herein, refers to a polymeric material that includes materials previously used in a consumer or industry application i.e., pre-consumer recycled polymer and post-industrial recycled polymer. PCR is typically collected from recycling programs and recycling plants. The PCR may include one or more of an ethylene-based polymer, such as LDPE, LLDPE, polyethylene, a polypropylene, a polyester, a poly(vinyl chloride), a polystyrene, an acrylonitrile butadiene styrene, a polyamide, an ethylene vinyl alcohol, an ethylene vinyl acetate, or a poly-vinyl chloride. The PCR may include one or more contaminants. The contaminants may be the result of the polymeric material’s use prior to being repurposed for reuse. For example, contaminants may include paper, ink, food residue, or other recycled materials in addition to the polymer, which may result from the recycling process. PCR is distinct from virgin polymeric material. A virgin polymeric material (such as a virgin polyethylene resin) does not include materials previously used in a consumer or industry application. Virgin polymeric material has not undergone, or otherwise has not been subject to, a heat process or a molding process, after the initial polymer manufacturing process. The physical, chemical, and flow properties of PCR polyethylene resins differ when compared to virgin polymeric resin, which in turn can present challenges to incorporating PCR into formulations for commercial use. [0026] EMBODIMENTS [0027] As depicted in FIG. 1, a multilayer film 100 may comprise a first outer layer 102, a second outer layer 104, and a core layer 106. The core layer 106 may be positioned between the first outer layer 102 and the second outer layer 104. In one or more embodiments, the multilayer film may also include one core layer or a plurality of core layers, for example, three core layers. Whether including one or more core layers, one or more of the core layers may comprise PCR polyethylene resin. [0028] Core Layer(s) [0029] The core layer(s) 106 may include post-consumer recycled (PCR) polyethylene resin having a density of 0.930 to 0.950 g/cc as determined according to ASTM D792, a melt index 85477-WO-PCT/DOW 85477 WO (I₂) of 1.0 to 3.0 dg/min as determined according to ASTM D1238 (2.16 kg, 190 °C), and a molecular weight distribution (MWD=Mw/Mn) of 5 to 12, as measured by conventional gel permeation chromatography (GPC), where MWD is defined as Mw/Mn with Mw being a weight-average molecular weight and M_n being a number-average molecular weight. [0030] In further embodiments, the PCR polyethylene resin may have a density of from 0.935 g/cc to 0.950 g/cc, from 0.935 g/cc to 0.945 g/cc, from 0.930 g/cc to 0.945 g/cc, from 0.930 g/cc to 0.940 g/cc, from 0.940 g/cc to 0.950 g/cc, or any subset thereof. [0031] In other embodiments, the PCR polyethylene resin may have a melt index (I₂) of from 1 dg/min to 2.5 dg/min, from 1 dg/min to 2 dg/min, from 1.5 dg/min to 3 dg/min, from 1.5 dg/min to 2.5 dg/min, from 1.5 dg/min to 2.5 dg/min, or any subset thereof. [0032] In other embodiments, the PCR polyethylene resin may have an MWD of from 6 to 12, from 7 to 12, from 7 to 11, from 7 to 10, or any subset thereof. [0033] The PCR polyethylene resin may include a gel level (GI200) of 15 to 125, which is a count of defect with an equivalent circular diameter in the range of 200-400 µm (per 24.6 cm³ of film). In further embodiments, the PCR polyethylene resin may have a gel level of 15 to 100. A typical virgin resin has a gel level of less than 10. [0034] In some embodiments, the PCR polyethylene resin may optional include some additional polyolefin PCR materials, such as propylene-based PCR resin or additional ethylene-based PCR resins. [0035] While the core layer(s) may only include PCR polyethylene resin, the core layer(s) 106 may include blends of PCR polyethylene resin and virgin ethylene-based polymer. In one or more embodiments, the core layer may include 5 to 100 wt.%, 5 to 50 wt.%, 10 to 40 wt.%, 20 to 40 wt.% of the PCR polyethylene resin. Conversely, the core layer may include 0 to 95 wt.%, 50 to 95 wt.%, 60 to 90 wt.%, 60 to 80 wt.% of the virgin ethylene-based polymer. [0036] The core layer(s) 106 may also include virgin ethylene-based polymer having a density 0.900 g/cc to 0.968 g/cc and a melt index (I2) of 0.2 to 5 dg/min. In one embodiment, the virgin ethylene-based polymer may comprise LLDPE. [0037] The LLDPE may have a melt index (I₂) from 0.2 dg/min to 5 dg/min, from 0.5 dg/min to 4 dg/min, from 0.5 dg/min to 3 dg/min, from 2 dg/min to 5 dg/min, from 3 dg/min to 6 dg/min, or any subset thereof. In embodiments, the multilayer film 100 may be a cast stretch film and the LLDPE may have a melt index (I₂) of from 2 dg/min to 5 dg/min. In 85477-WO-PCT/DOW 85477 WO embodiments, the multilayer film 100 may be a blown film and LLDPE may have a melt index (I2) of from 0.5 dg/min to 3 dg/min. [0038] The LLDPE may have a density of from 0.916 g/cc to 0.935 g/cc. In embodiments, the LLDPE have a density of from 0.916 g/cc to 0.930 g/cc, from 0.916 g/cc to 0.925 g/cc, from 0.916 g/cc to 0.920 g/cc, from 0.925 g/cc to 0.935 g/cc, from 0.920 g/cc to 0.930 g/cc, or any subset thereof. [0039] In further embodiments, the core layer(s) 106 may comprise an LDPE. The LDPE can have a melt index (I₂) in the range of from 1 dg/min to 50 dg/min. All individual values and subranges of from 1 dg/min to 50 dg/min are disclosed and included herein. For example, the LDPE can have a melt index (I2) in the range of from 1 dg/min to 20 dg/min, from 2 dg/min to 10 dg/min, from 2 dg/min to 8 dg/min, or any subset thereof. [0040] Outer Layers [0041] Referring again to FIG. 1, the first outer layer 102 and the second outer layer 104 comprise ethylene-based polymer, propylene-based polymer, or combinations thereof. While the disclosed embodiments focus on virgin ethylene-based polymer or virgin propylene-based polymer in the first outer layer 102 and the second outer layer 104, it is contemplated that the first outer layer 102 and the second outer layer 104 may include PCR polyethylene resin. [0042] In one embodiment, the first outer layer 102 may serve as a release layer. A release layer, for example, may have non-cling characteristics or may exhibit lower cling characteristics than a cling layer. The first outer layer 102 may comprise any material suitable for use as a release layer. The second outer layer 104 may be a cling layer. Cling layers, for example, may enable the multilayer film 100 to cling to itself when the film is wrapped on a load. The second outer layer 104 may comprise any material suitable for use as a cling layer. [0043] The first outer layer 102, the second outer layer 104, or both may comprise ethylene- based polymer, such LLDPE, which has the density and melt index (I2) ranges. In embodiments, the first outer layer 102 may comprise at least 50 wt.%, such as at least 60 wt.%, at least 70 wt.%, at least 80 wt.%, at least 90 wt.%, or even at least 99 wt.% of LLDPE. [0044] In some embodiments, the first outer layer 102 and/or the second outer layer 104 may comprise an LDPE. The LDPE can have a melt index (I2) in the range of from 1 dg/min to 50 dg/min. All individual values and subranges of from 1 dg/min to 50 dg/min are disclosed and included herein. For example, the LDPE can have a melt index (I₂) in the range of from 85477-WO-PCT/DOW 85477 WO 1 dg/min to 20 dg/min, from 2 dg/min to 10 dg/min, from 2 dg/min to 8 dg/min, or any subset thereof. [0045] In some embodiments, the ethylene-based polymer of first outer layer 102, and/or the second outer layer 104 can independently comprise from 0 wt.% to 30 wt.% of the LDPE, based on the total weight of the respective layer. All individual values of 0 wt.% to 30 wt.% are disclosed and included herein. For example, the multilayer film 100 can comprise from 0 wt.% to 25 wt.%, from 0 wt.% to 20 wt.%, from 0 wt.% to 10 wt.%, from 0 wt.% to 5 wt.%, from 5 wt.% to 30 wt.%, from 5 wt.% to 20 wt.%, or any subset thereof, based on the total polymer weight of the respective layer. [0046] The first outer layer 102, the second outer layer 104, or both may comprise propylene-based polymer. The polypropylene may comprise polypropylene homopolymer or random copolymer. The polypropylene may have been catalyzed by a Ziegler–Natta catalyst, a single site/metallocene catalyst or a post-metallocene catalyst. [0047] The polypropylene may comprise at least 51 wt.% of the propylene monomer, based on the total polymer weight of the polypropylene. In embodiments, the polypropylene may comprise at least 50 wt.%, at least 60 wt.%, at least 70 wt.%, at least 75 wt.%, at least 80 wt.%, at least 85 wt.%, at least 90 wt.%, at least 95 wt.%, at least 99 wt.%, at least 99.9 wt.%, or even 100 wt.% of the propylene monomer, based on the total polymer weight of the polypropylene. [0048] In one embodiment, the propylene based polymer is a polypropylene plastomer. The polypropylene plastomer may have a density of from 0.850 g/cc to 0.910 g/cc. In embodiments, the polypropylene plastomer may have a density of from 0.860 g/cc to 0.890 g/cc, from 0.860 g/cc to 0.880 g/cc, from 0.860 g/cc to 0.875 g/cc, from 0.860 g/cc to 0.870 g/cc, from 0.865 g/cc to 0.870 g/cc, or any subset thereof. [0049] The polypropylene plastomer may have a melt flow rate (MFR) of from 2 dg/min to 50.0 dg/min. In embodiments, the polypropylene plastomer may have an MFR of from 5 dg/min to 25 dg/min, from 6 dg/min to 15 dg/min, from 7 dg/min to 10 dg/min, from 7.5 dg/min to 8.5 dg/min, or any subset thereof. [0050] While the first outer layer 102, the second outer layer 104, or both may be monomaterial and solely comprise ethylene-based polymer or propylene-based polymer, the first outer layer 102, the second outer layer 104, or both may include blends of ethylene- 85477-WO-PCT/DOW 85477 WO based polymer or propylene-based polymer. In one or more embodiments, the first outer layer 102, the second outer layer 104, or both may include an amount of ethylene-based polymer ranging from a lower limit 0, 10, 20, 30, 40, 50, 60, 70, 80 or 90 wt.% to an upper limit of 100, 90, 80, 70, 60, 50, 40, 30, 20, or 10 wt.%. Conversely, the first outer layer 102, the second outer layer 104, or both may include an amount of propylene-based polymer ranging from a lower limit 0, 10, 20, 30, 40, 50, 60, 70, 80 or 90 wt.% to an upper limit of 100, 90, 80, 70, 60, 50, 40, 30, 20, or 10 wt.%. [0051] Intermediate Layers [0052] Optionally, there may be intermediate layers (not shown) disposed between the core layer 106 and the first outer layer 102 and the second outer layer 104. Similar to the first outer layer 102 and the second outer layer 104, the intermediate layers may include ethylene- based polymer, propylene-based polymer, or combinations thereof. [0053] The intermediate layers may be monomaterial and solely comprise ethylene-based polymer or propylene-based polymer; however, these layers may also include blends of ethylene-based polymer or propylene-based polymer. In one or more embodiments, the intermediate layers may include an amount of ethylene-based polymer ranging from a lower limit 0, 10, 20, 30, 40, 50, 60, 70, 80 or 90 wt.% to an upper limit of 100, 90, 80, 70, 60, 50, 40, 30, 20, or 10 wt.%. Conversely, the intermediate layers may include an amount of propylene-based polymer ranging from a lower limit 0, 10, 20, 30, 40, 50, 60, 70, 80 or 90 wt.% to an upper limit of 100, 90, 80, 70, 60, 50, 40, 30, 20, or 10 wt.%. [0054] Additives [0055] It should be understood that any of the foregoing layers can further comprise one or more additives as known to those of skill in the art such as, for example, antioxidants, ultraviolet light stabilizers, thermal stabilizers, slip agents, antiblock agents, antistatic agents, pigments or colorants, processing aids, crosslinking catalysts, flame retardants, fillers and foaming agents. The layer may contain any amounts of such additives, such as from 0 wt.% to 10 wt.%, from 0 wt.% to 5 wt.%, from 0 wt.% to 1 wt.%, from 0 wt.% to 0.1 wt.%, from 0 wt.% to 0.001 wt.%, or any subset thereof, based on a weight of the layer. [0056] The Multilayer Film [0057] The multilayer film 100, 200 may have a thickness of less than 70 µm. As described previously, it is desired to create multilayer films, which can meet the required mechanical 85477-WO-PCT/DOW 85477 WO properties while minimizing the thickness of the film. In embodiments, the multilayer film 100, 200 may have a thickness of less than 60 µm, less than 50 µm, less than 40 µm, less than 30 µm, less than 25 µm, less than 23 µm, less than 19 µm, from 10 µm to 70 µm, from 10 µm to 50 µm, from 10 µm to 30 µm, from 10 µm to 25 µm, from 10 µm to 20 µm, from 15 µm to 70 µm, from 15 µm to 50 µm, from 15 µm to 30 µm, from 15 µm to 25 µm, from 15 µm to 20 µm, or any subset thereof. [0058] It should be understood that the multilayer film 100 may comprise 3 or more layers. In embodiments, the multilayer film may comprise more than 5 layers, such as 5, 7, 9, or 11 layers. The multilayer film 100 may be a blown film or a cast film. In one embodiment, the cast film is a stretch film. In stretch film embodiments, the multilayer film has an ESTL tear resistance greater than 7 seconds, ESTL puncture greater than 5.5 lb. and Ultimate Stretch higher than 200%. [0059] TEST METHODS [0060] Density [0061] Density is measured in accordance with ASTM D792, and expressed in grams/cc (g/cc). [0062] Melt Index (I2) [0063] Melt Index (I₂) is measured in accordance with ASTM D 1238-10 at 190 °C and 2.16 kg, Method B, and is expressed in dg/min eluted. [0064] Melt Flow Rate (MFR) [0065] Melt Flow Rate is measured in accordance with ASTM D 1238-10 at 230 °C and 2.16 kg, Method B, and is expressed in dg/min eluted. [0066] Conventional GPC (Mw, Mn, Mw/Mn) [0067] Details of the GPC method can be found in U.S. Patent Application Number 17/632598, which is incorporated by reference herein. [0068] Gel Level (GI200) Defect Count [0069] The Defect Count is a measure of defects that are detected in an extruded film using optical imaging technology according to the practices and guidance in ASTM D7310-20 “Standard Practice for Defect Detection and Rating of Plastic Film Using Optical Sensors.” The Defect Count is reported as the number of optical defects per 24.6 cm³ with an effective circular diameter within defined series of ranges: 200-400 µm, 400-800 µm, 800-1600 µm, 85477-WO-PCT/DOW 85477 WO 1600µm and above. It is measured by an Optical Control Systems Film Surface Analyzer FSA100 (OCS FSA100) optical imaging system. The OCS FSA100 optical imaging system consists of a lighting unit, a Charge Coupled Device (CCD) line scan camera, and a computer with image/data analysis software version 5.0.4.6. [0070] The OCS FSA100 optical imaging system detects defects as they obscure the transmission of halogen-based source light. Average greyscale was set to 170 with a threshold sensitivity setting of 35%. Additionally, the gain of the CCD system may be adjusted to compensate for film haziness. The imaging system creates a composite area of each defect by adding the defective pixels from each subsequent line scan. The system then reports the number of defects which were in user defined size ranges, based on the diameter of circles having equivalent areas. [0071] Film fabrication is accomplished by an OCS ME19 cast film extrusion system equipped with a fixed lip coat hanger die. Die gap is 500 µm by 15 cm. It is a single screw extruder equipped with a 19 mm screw provided by OCS. The screw design is a 3:1 L/D compression ratio with a pineapple mixing tip. Total extrusion system mass output is 10 ± 5 kg / hour. Film thickness was 38 µm, which was achieved via adjustment of the chill roll. A nitrogen purge was used at the feed throat of the extruder. Temperature profiles ranged from 135 °C - 190 °C to achieve a target extrusion pressure of 220-240 Bar. [0072] The PCR resin was analyzed by diluting it (50/50 wt.%) with virgin polyethylene in a dry blend prior to extrusion. The virgin polyethylene used for dilution was LDPE 132I (with a density of 0.921 g/cm3 and a melt index of 0.25 dg/min measured at 190 degrees Celsius and 2.16 kg), commercially available from The Dow Chemical Company. [0073] ESTL Ultimate stretch [0074] This test was executed on ESTL FPT-750 equipment. The test includes incrementally stretching of the film until it breaks with rollers at different speeds, similar to the mechanisms of pallet wrappers. This test reports the forces in the unwind section, forces on the wind drum, forces required to stretch the film, peel-off angle, peel-off force and unwind noise. [0075] Highlight Ultimate Stretch [0076] This test was also executed in ESTL FPT-750 equipment. The test includes incrementally stretching of the film until it breaks with rollers at different speeds, similar to 85477-WO-PCT/DOW 85477 WO the mechanisms of pallet wrappers. This test reports maximum elongation when the film breaks due to stretching. [0077] ESTL Puncture [0078] This test was executed on ESTL FPT-750 equipment. The film is stretched to a certain pre-defined pre-stretch level (250%), and then there is a 10 second pause. Next the film is clamped with a frame and counter frame, so a sharp puncture probe can travel with a fixed pre-defined speed until it reaches the film. This test reports the maximum force, displacement and energy to puncture the film. [0079] ESTL Tear propagation [0080] This test was executed on ESTL FPT-750 equipment. The film is stretched to a certain pre-defined pre-stretch level (250%). Next the film is clamped with a frame and counter frame, so a sharp blade can travel with a fixed pre-defined speed until it reaches the film. After the incision is made, the clamp is opened and the forces in the film are monitored. If the tear does not propagate, the wind drum will start to slowly pull until the film completely breaks. [0081] EXAMPLES Table 1 – Commercial Resins

85477-WO-PCT/DOW 85477 WO

[0082] ELITE™ 5230G, DOWLEX™ 2047G, and DOWLEX™ 2247G, which are produced from Dow™ Inc., Midland, MI, are Linear Low-Density Polyethylenes (LLDPE) comprising octene comonomer. [0083] VERSIFY™ 3300 is a polypropylene elastomer produced from Dow™ Inc., Midland, MI. [0084] PCR HDPE 94020 is a post-consumer recycle polyethylene with a low level of gels compared to post-consumer recycle resins made from stretch films. PCR HDPE 94020 is produced by Enka Company, Colombia. The gel level has been analyzed according to GI200 and the value is between 19 and 100. PCR is obtained from a mechanical recycling process wherein HDPE is obtained as a sub-product from the recycling process. The PCR is washed and then the PE is separated from the other materials by density to obtain a full PE stream. This stream is then washed again, dried and fed to the extruder to produce the final PCR composition, which is provided in Table 2 below. Table 2 – PCR HDPE 94020 Composition

85477-WO-PCT/DOW 85477 WO [0085] PCR #2 and PCR #3 are post-consumer recycle LLDPE resins made from recovered stretch films. [0086] Films were extruded on a 5-Layer Egan Davis Standard cast line, using the film structures provided in Tables 3-4 as follows and the process conditions of Table 4 as follows. All cast films were produced with a thickness of 20 µm. Table 3 – Compositions for Comparative 5 Layer Films

85477-WO-PCT/DOW 85477 WO Table 4 – Compositions for Inventive 5 Layer Films

85477-WO-PCT/DOW 85477 WO Table 5 – Processing Conditions for 5 Layer Films

85477-WO-PCT/DOW 85477 WO

[0087] 3 Layer Cast Films were extruded on a Egan Davis Standard cast line, using the film structures provided in Table 6 as follows and the process conditions of Table 7 as follows. All cast films were produced with a thickness of 20 µm. Table 6 – Compositions for 3 Layer Films

85477-WO-PCT/DOW 85477 WO

Table 7 – Processing Conditions for 3 Layer Films

85477-WO-PCT/DOW 85477 WO Table 8 – Stretch Properties for 5 Layer Films

Table 9 – Stretch Properties for 3 Layer Films

[0088] Referring to Table 8, 5-Layer Inventive Examples 1-4 all delivered a higher tear resistance compared to the 5-Layer Comparative Example 1, which did not include PCR resin. Furthermore, Inventive Examples 1-4 all delivered a higher tear resistance compared to Comparative Example 2, which included PCR LLDPE. Moreover, the 5-Layer Inventive 85477-WO-PCT/DOW 85477 WO Example 1 demonstrated an improved ultimate stretch using a simulated 3-layer core with PCR in each layer. [0089] Inventive Example 4, a 5-layer solution showed improved tear resistance compared to a simulated 3-film like Inventive Example 1 by the inclusion of intermediate layers without PCR between the core and cling/release layers. Moreover, Inventive Example 4 had better processing parameters such as lower pressure compared to Comparative Example 2 and process stability compared to Comparative Example 3, which was not stable enough to run the cast extrusion line. These Examples demonstrate that the PCR can be used to produce a more sustainable high-quality stretch film with minimum reduction in ultimate stretch and puncture, while improving tear resistance. [0090] Referring to Table 9, Inventive Examples 5 and 6, which are three layers films, provide sustainability while still maintaining excellent ESTL Ultimate Stretch. While there may be a slight drop off in ESTL Ultimate Stretch, this drop still more than meets stretch wrap specifications, which tend to require ESTL Ultimate Stretch of 250-300%. [0091] While particular embodiments of the present disclosure have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the disclosure. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this disclosure.

Claims

85477-WO-PCT/DOW 85477 WO CLAIMS 1. A multilayer film comprising a first outer layer, a second outer layer, and at least one core layer positioned between the first outer layer and the second outer layer, wherein: the at least one core layer comprises post-consumer recycled (PCR) polyethylene resin having a density of 0.930 to 0.950 g/cc as determined according to ASTM D792, a melt index (I2) of 1.0 to 3.0 dg/min as determined according to ASTM D1238 (2.16 kg, 190 °C), and a molecular weight distribution (MWD=Mw/Mn) of 5 to 12; and the first outer layer and the second outer layer comprise ethylene-based polymer, propylene-based polymer, or combinations thereof. 2. The multilayer film of claim 1, wherein the at least one core layer further comprises virgin ethylene-based polymer having a density 0.900 g/cc to 0.968 g/cc and a melt index (I2) of 0.2 to 5 dg/min. 3. The multilayer film of claim 1 or 2, wherein the at least one core layer comprises a plurality of core layers, wherein one or more of the plurality of core layers comprise the PCR polyethylene resin. 4. The multilayer film of any one of claims 1 to 3, wherein the ethylene-based polymer of the first outer layer and/or the second outer layer comprise linear low-density polyethylene (LLDPE). 5. The multilayer film of any one of claims 1 to 4, wherein the propylene-based polymer of the first outer layer and/or the second outer layer comprise polypropylene plastomer. 6. The multilayer film of any one of claims 1 to 5, wherein the at least one core layer comprises 5 to 100 wt.% of the PCR polyethylene resin. 7. The multilayer film of any one of claims 1 to 6, wherein the multilayer film comprises 5 to 50 wt.% of the PCR polyethylene resin, preferably 10 to 40 wt.% of the PCR polyethylene resin, more preferably 20 to 40 wt.% of the PCR polyethylene resin. 8. The multilayer film of any one of claims 1 to 7, wherein the PCR polyethylene resin comprises a gel level (G1200) of 15 to 125. 85477-WO-PCT/DOW 85477 WO 9. The multilayer film of any one of claims 1 to 8, wherein the multilayer film has ESTL tear resistance greater than 7 seconds, ESTL puncture greater than 5.5 lb. and ESTL Ultimate Stretch higher than 200%. 10. The multilayer film of any one of claims 1 to 9, wherein the multilayer film is a stretch film.