PCR Blends and Films

Abstract

The present disclosure provides a composition. In one embodiment, the composition includes: (A) 40% to 70% by weight of a high density polyethylene post-consumer resin (HDPE-PCR); and (B) 60% to 30% by weight of a polyethylene enhancer. The polyethylene enhancer has (i) a density of 0.88 g / cc to 0.90 g / cc, (ii) a melt index of 0.5 g / 10 min to 0.85 g / 10 min, and (iii) an I of 5.5 to 8.0. 10 (C) The composition has (1) a density of 0.910 g / cc to 0.935 g / cc, and (2) a melt index of 0.5 g / 10 min to 0.85 g / 10 min. The present disclosure also provides a film made from the composition. The present disclosure provides a composition. In one embodiment, the composition includes (A) 40 wt% to 70 wt% high density polyethylene post-consumer resin (HDPE-PCR) and (B) 60 wt% to 30 wt% polyethylene enhancer. The polyethylene enhancer has (i) a density of 0.88 g / cc to 0.90 g / cc, (ii) a melt index of 0.5 g / 10 min to 0.85 g / 10 min, and (iii) an I2 value of 5.5 to 8.0. 10 / I2 value. (C) The composition has (1) a density of 0.910 g / cc to 0.935 g / cc, and (2) a melt index of 0.5 g / 10 min to 0.85 g / 10 min. The present disclosure also provides a film made from the composition.

Description

[Technical Field]

[0001] Polyethylene compositions for packaging applications, films, multilayer structures, and packaging articles made therefrom are known. For packaging applications, polyethylene compositions require a combination of toughness while exhibiting good tear strength. Balancing enhanced abuse performance (e.g., dart, puncture, and tear) without sacrificing overall material rigidity remains a common challenge in the field. Materials that can achieve a better balance of packaging performance are increasingly needed as packaging design moves toward single-material structures to support packaging sustainability efforts. [Background technology]

[0002] In an effort to improve recyclability and expand sustainability, the flexible packaging market is moving toward blends of (i) "post-consumer recycled" (PCR) resins (plastic materials that have been used and then recycled) with (ii) virgin plastic resins to produce PCR / blend resins suitable for use in packaging applications. Such efforts reduce the amount of waste plastic sent to landfills.

[0003] However, PCR / virgin blend resins have certain drawbacks. High gel content in films made from conventional PCR / virgin blend resins causes performance degradation and sudden failure in end applications. High gel content also contributes to poor aesthetics in the final packaging. PCR / virgin blend resins also cause bubble stability issues during the blown film extrusion process, limiting the amount of PCR incorporation in the final film formulation.

[0004] The art recognizes a continuing need for plastic formulations in which the percentage of PCR resin in the final PCR / virgin blend resin is ever increasing, and the PCR / virgin blend resin also maintains properties (modulus, and impact and tear resistance) suitable for film and packaging applications. Summary of the Invention

[0005] The present disclosure provides a composition. In one embodiment, the composition includes: (A) 40% to 70% by weight of a high density polyethylene post-consumer resin (HDPE-PCR); and (B) 60% to 30% by weight of a polyethylene enhancer. The polyethylene enhancer has (i) a density of 0.88 g / cc to 0.90 g / cc, (ii) a melt index of 0.5 g / 10 min to 0.85 g / 10 min, and (iii) an I of 5.5 to 8.0. 10 / I2 value. (C) The composition has (1) a density of 0.910 g / cc to 0.935 g / cc, and (2) a melt index of 0.5 g / 10 min to 0.85 g / 10 min. The present disclosure also provides a film made from the composition. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a schematic diagram of a polymerization reactor system according to one embodiment of the present disclosure.

[0007] definition Any references to the Periodic Table of the Elements are to the table as published in 1990-1991 by CRC Press, Inc. References to element groups in this table are to the new notation for numbering groups.

[0008] For purposes of United States patent practice, the contents of any referenced patent, patent application, or publication are incorporated by reference in their entirety (or the equivalent United States version thereof is so incorporated by reference), particularly with respect to the disclosure of definitions (to the extent not inconsistent with any definitions specifically provided in this disclosure).

[0009] Numerical ranges disclosed herein include all values ​​between and including the lower and upper limits. Ranges containing explicit values ​​(e.g., 1 or 2, or 3-5, or 6, or 7) include all subranges between any two explicit values ​​(e.g., the range 1-7 above includes subranges such as 1-2, 2-6, 5-7, 3-7, 5-6, etc.).

[0010] Unless stated to the contrary, implicit from the context, or customary in the art, all parts and percentages are by weight and all test methods are current as of the filing date of this disclosure.

[0011] As used, the terms "blend" or "polymer blend" refer to a mixture of two or more polymers. A blend may or may not be miscible (not phase separated at the molecular level). A blend may or may not be phase separated. A blend may or may not contain one or more domain configurations as determined from transmission electron spectroscopy, light scattering, x-ray scattering, and other methods known in the art. Blending can be achieved by physically mixing two or more polymers at a macro level (e.g., melt blending or compounding of resins) or at a micro level (e.g., co-forming in the same reactor).

[0012] The term "composition" refers to a mixture of materials that comprise the composition, as well as reaction products and decomposition products formed from the materials of the composition.

[0013] The terms "comprising," "including," "having," and their derivatives are not intended to exclude the presence of any additional component, step, or procedure, whether specifically disclosed or not. For the avoidance of doubt, all compositions claimed through the use of the term "comprising" may include any additional additive, adjuvant, or compound, whether polymeric or otherwise, unless stated to the contrary. In contrast, the term "consisting essentially of" excludes from the scope of any preceding description any other component, step, or procedure, except those that are not essential to operability. The term "consisting of" excludes any component, step, or procedure not specifically delineated or listed. The term "or" refers to the listed members individually and in any combination, unless otherwise stated.

[0014] An "ethylene-based polymer" is a polymer that contains greater than 50 mole percent (wt%) polymerized ethylene monomer (based on the total amount of polymerizable monomers), and may optionally contain at least one comonomer. Ethylene-based polymers include ethylene homopolymers and ethylene copolymers (meaning units derived from ethylene and one or more comonomers). The terms "ethylene-based polymer" and "polyethylene" may be used interchangeably. Ethylene-based polymers are polymers that contain α-olefins (e.g., C3-C6 12 It may comprise ethylene copolymerized with an α-olefin, or a C4 to C8 α-olefin) and / or an unsaturated ester.

[0015] As used herein, the terms “ethylene monomer” or “ethylene” refer to a chemical unit having two carbon atoms with a double bond between them, and each carbon bonded to two hydrogen atoms, that can be polymerized with other such chemical units to form an ethylene-based polymer composition.

[0016] A "heteroatom" is an atom other than carbon or hydrogen. Heteroatoms can be non-carbon atoms from Groups IV, V, VI, and VII of the periodic table. Non-limiting examples of heteroatoms include F, N, O, P, B, S, and Si.

[0017] A "hydrocarbon" is a compound containing only hydrogen and carbon atoms. A "hydrocarbonyl" (or "hydrocarbonyl group") is a hydrocarbon having a valency (typically monovalent). The hydrocarbon can have a linear, cyclic, or branched structure.

[0018] "Linear low density polyethylene" (or "LLDPE") is a polymer consisting of units derived from ethylene and at least one C3-C 10 LLDPE is a linear ethylene / α-olefin copolymer containing a heterogeneous short-chain branching distribution, comprising units derived from an α-olefin comonomer, or at least one C4-C8 α-olefin comonomer, or at least one C6-C8 α-olefin comonomer. LLDPE, in contrast to conventional LDPE, is characterized by the presence of little, if any, long-chain branching. LLDPE has a density of 0.910 g / cc, 0.915 g / cc, 0.920 g / cc, or 0.925 g / cc to 0.930 g / cc, 0.935 g / cc, or 0.940 g / cc. Non-limiting examples of LLDPE include TUFLIN™ linear low-density polyethylene resin and DOWLEX™ polyethylene resin, each available from The Dow Chemical Company, and MARLEX™ polyethylene (available from Chevron Phillips).

[0019] "Low density polyethylene" (or "LDPE") consists of ethylene homopolymer or ethylene copolymer with acrylate, vinyl acetate, and / or vinyl silane as comonomers; LDPE has a density of 0.915 g / cc to 0.940 g / cc and contains long chain branching with a broad molecular weight distribution (MWD). LDPE is typically produced by high-pressure free-radical polymerization (tubular reactor or autoclave using a free-radical initiator). Non-limiting examples of LDPE include MarFlex™ (Chevron Phillips), LUPOLEN™ (LyondellBasell), and LDPE products from Borealis, Ineos, ExxonMobil, and others.

[0020] "Medium density polyethylene" (or "MDPE") is an ethylene homopolymer or at least one C3 to C6 copolymer having a density between 0.926 g / cc and 0.940 g / cc. 10 It is an ethylene / α-olefin copolymer containing an α-olefin or a C3-C4 α-olefin.

[0021] An "olefin" is an unsaturated aliphatic hydrocarbon containing a carbon-carbon double bond.

[0022] An "olefin-based polymer" (interchangeably referred to as a "polyolefin") is a polymer that contains a majority weight percent polymerized olefin monomer (based on the total amount of polymerizable monomers), and may optionally contain at least one comonomer. Non-limiting examples of olefin-based polymers include ethylene-based polymers and propylene-based polymers.

[0023] As used herein, the term "polymer" or "polymeric material" refers to a compound prepared by polymerizing monomers, whether of the same or different types, to provide, in polymerized form, the multiple and / or repeating "units" or "mer units" that make up the polymer. Thus, the general term polymer encompasses the term homopolymer, which is commonly used to refer to a polymer prepared from only one type of monomer, and the term copolymer, which is commonly used to refer to a polymer prepared from at least two types of monomer. It also encompasses all forms of copolymers, e.g., random, block, etc. The terms "ethylene / α-olefin polymer" and "propylene / α-olefin polymer" refer to the above-described copolymers prepared by polymerizing ethylene or propylene, respectively, and one or more additional polymerizable α-olefin monomers. While polymers are often referred to as "made of" one or more specified monomers, "based on" specified monomers or types of monomers, "containing" specified monomer content, etc., it should be noted that in this context, the term "monomer" is understood to refer to the polymerized residue of the specified monomer, and not to the unpolymerized species. Generally, polymers herein are referred to as being based on "units" that are the polymerized form of the corresponding monomers.

[0024] A "propylene-based polymer" is a polymer that contains more than 50 mole percent polymerized propylene monomer (based on the total amount of polymerizable monomers) and may optionally contain at least one comonomer. Propylene-based polymers include propylene homopolymers and propylene copolymers (meaning units derived from propylene and one or more comonomers). The terms "propylene-based polymer" and "polypropylene" may be used interchangeably. Non-limiting examples of propylene-based polymers (polypropylenes) include those containing at least one C2 or C4-C 10 It is a propylene / α-olefin copolymer with an α-olefin comonomer.

[0025] Test Method Dart Impact: Dart impact is measured according to ASTM D1709. Results are reported in impact break weight in grams (g).

[0026] Defect count is a measure of defects detected in extruded film using optical imaging techniques in accordance with ASTM D7310-20, "Standard Practice for Defect Detection and Rating of Plastic Film Using Optical Sensors." Defect counts are measured within a series of specified ranges: 400-800 μm, 800-1600 μm, and 24.6 cm2 films with effective circular diameters of 1600 μm or greater. 3 Optical defect area per film (mm 2 ) which is measured by an 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.

[0027] The OCS FSA100 optical imaging system detects defects that obscure the transmission of halogen-based light. The average grayscale was set to 170 with a threshold sensitivity setting of 35%. Additionally, the gain of the CCD system can be adjusted to compensate for film haze. The imaging system creates a composite area for each defect by adding the defect pixels from each subsequent line scan. The system then reports the area of ​​defects that fall within a user-defined size range based on the diameter of a circle with an equivalent area.

[0028] For defect counts, 2-mil thick blown films were produced as follows: A gravimetric feeder fed the resin formulation into a Labtech LTE20-32 twin-screw extruder at a rate of 15 lb / hr. From the extruder, the resin formulation was conveyed to a 2-inch diameter die with a 1.0 mm gap. The LTE feed throat was set at 193°C, and the remaining barrel, conveying section, and die temperatures were set and maintained at 215°C. Pressurized ambient air expanded the film bubble to a blow-up ratio of 2.5. A dual-lip air ring driven by a variable-speed blower was used for all experiments. The frost line height (FLH) was maintained between 8.8 and 10.8 inches. Film thickness was targeted at 2 mils and controlled within ±15% by adjusting the nip roller speed. The film was wound into a roll.

[0029] Density is measured according to ASTM D792, Method B. Results are reported in grams per cubic centimeter (g / cc).

[0030] Limonene Content. Limonene content is measured by headspace gas chromatography. Results are reported in parts per million (or "ppm").

[0031] Melt Index. As used herein, the term "melt index" or "MI" refers to a measure of how easily a thermoplastic polymer flows when in a molten state. Melt index, or MI, is a measure of how easily a thermoplastic polymer flows when in a molten state. Z is determined in accordance with ASTM D 1238, condition 190°C / 2.16 kg, and is reported in grams dissolving per 10 minutes (g / 10 min). I10 is determined in accordance with ASTM D 1238, condition 190°C / 10 kg, and is reported in grams dissolving per 10 minutes (g / 10 min).

[0032] 2% Secant Modulus. Secant modulus was measured as described herein. Film samples were conditioned for at least 40 hours at 23°C (±2°C) and 50% RH (±10%) according to ASTM standards before testing, which was performed at 23°C (±2°C) and 50% RH (±10%) according to ASTM standards. Film strips measuring 1 inch wide by 8 inches long were cut from the film in the desired directions (machine direction (MD) and cross direction (CD)). The specimens were loaded into a tensile test frame using line grip jaws (flat rubber on one side of the jaw and line grips on the other) set at a 4-inch gauge length. The specimens were elongated to a maximum of 5% nominal strain at a crosshead speed of 2 inches / minute. Secant modulus is the ratio of stress at a specific strain to the specific strain, measured at the specific strain and determined from the load-elongation curve. Typically, secant modulus at 1% and 2% strain is calculated. Typically, five replicates are tested for each sample. Secant modulus results are reported in ksi (1000 psi).

[0033] Tear - Machine Direction (MD). The Elmendorf tear test uses an Elmendorf-type tear tester to determine the average force required to propagate a tear through a specified length of plastic film or non-rigid sheeting after the tear has been initiated. The film is conditioned for at least 40 hours at 23°C (+ / - 2°C) and 50% RH (+ / - 10°C) according to ASTM standards. Standard test conditions are 23°C (± 2°C) and 50% RH (± 10°C) according to ASTM standards. The force (grams) required to propagate a tear through a film or sheeting specimen is measured using a precisely calibrated pendulum device. Acting under gravity, the pendulum swings through an arc, tearing the specimen from a pre-cut slit. The specimen is held on one side by the pendulum and on the other side by a fixture. The loss of energy by the pendulum is indicated by a pointer or by an electronic balance. The scale reading is a function of the force required to tear the specimen. The samples used are "constant radius geometry" as specified in ASTM D1922. Testing is performed on samples cut in the MD. Prior to testing, the thickness of the sample is measured at the center of the sample. A total of 15 specimens are tested, and the average tear strength is reported. Samples torn at an angle greater than 60° from the vertical are described as "diagonal" tears, and although such tears should be noted, the strength value is included in the average strength calculation. Tear resistance results are reported in grams force (gf). DETAILED DESCRIPTION OF THE INVENTION

[0034] The present disclosure provides a polyethylene composition. In one embodiment, the polyethylene composition comprises (A) 40 wt% to 70 wt% high density polyethylene post-consumer resin (HDPE-PCR). The polyethylene composition also comprises (B) 60 wt% to 30 wt% polyethylene enhancer, which enhances the polyethylene composition to have (i) a density of 0.88 g / cc to 0.90 g / cc, (ii) a melt index of 0.5 g / 10 min to 0.85 g / 10 min, and an I of 5.5 to 8.0. 10The polyethylene composition (C) includes a polyethylene enhancer having a density of 0.910 g / cc to 0.935 g / cc and a melt index of 0.5 g / 10 min to 0.85 g / 10 min.

[0035] The polyethylene composition comprises (A) 40% to 70% by weight of a high-density polyethylene post-consumer resin. As used herein, "high-density polyethylene" refers to an ethylene / C4 to C8 α-olefin copolymer having a density of 0.95 g / cc to 0.97 g / cc and a melt index of 0.2 g / 10 min to 2.0 g / 10 min.

[0036] In one embodiment, the high density polyethylene is (i) a density between 0.950 g / cc and 0.970 g / cc, or between 0.955 g / cc and 0.970 g / cc; and (ii) has a melt index of 0.2 g / 10 min to 2.0 g / 10 min, or 0.3 g / 10 min to 1.2 g / 10 min.

[0037] High-density polyethylene is high-density polyethylene post-consumer resin, or "HDPE-PCR." The term "post-consumer resin" (or "PCR") refers to polymeric materials previously used as consumer or industrial packaging. In other words, PCR is waste plastic. PCR is typically collected from recycling programs and recycling plants. PCR typically requires additional cleaning and processing before it can be reintroduced into the manufacturing line. PCR may include one or more of the following: ethylene-based polymers, propylene-based polymers, polyesters, poly(vinyl chloride), polystyrene, acrylonitrile butadiene styrene, polyamides, ethylene vinyl alcohol, ethylene vinyl acetate, or polyvinyl chloride. PCR may contain one or more contaminants. Contaminants may be the result of using the polymeric material before it is modified for reuse. In some embodiments, contaminants may include paper, ink, food residue, pigments, dyes, processing aids, stabilizing additives (e.g., antioxidants), fillers, flame retardants, other performance additives, odors (limonene), surface printing, paper labels, label adhesives, dirt, volatile organic compounds, nonvolatile organic compounds, or other recycled materials in addition to polymers, which may result from the recycling process. Contaminants may be particulate (e.g., fillers, dirt, particulate pigments, etc.) or non-particulate (e.g., dyes, odors, surfactants, volatile organic compounds, etc.). It is understood that PCR differs from post-industrial recycled (PIR) resins in that PIR resins have not reached the consumer. It is understood that similar principles described herein for PCR also apply to PIR resins.

[0038] PCR is different from virgin polymeric material. Because PCR has undergone an initial heating and molding process, PCR is not a "virgin" polymeric material. A "virgin polymeric material" is a polymeric material that has not been subjected to or has not been subjected to any heating or molding process other than those associated with the initial production of pellets or granules. The physical, chemical, and flow properties of PCR resins are different compared to virgin polymeric resins.

[0039] PCR is high density polyethylene-PCR ("HDPE-PCR"). Non-limiting examples of sources of HDPE-PCR include rigid HDPE packaging such as bottles (milk jugs, juice containers), and flexible HDPE packaging such as stand-up pouches and T-shirt bags. HDPE-PCR also contains residues from its original use, such as paper, adhesives, ink, ethylene vinyl alcohol (EVOH), polyamide (PA), polyethylene terephthalate (PET), and other odor-causing agents. HDPE-PCR is (i) a density between 0.950 g / cc and 0.970 g / cc, or between 0.955 g / cc and 0.970 g / cc; and (ii) has a melt index of 0.2 g / 10 min to 2.0 g / 10 min, or 0.3 g / 10 min to 1.2 g / 10 min.

[0040] Non-limiting examples of suitable HDPE-PCRs include PCRs sold by Envision Plastics, North Carolina, USA under the names EcoPrime™, PRISMA™, Natural HDPE PCR Resins, Mixed Color and Black HDPE PCR Resins; PCRs sold by KW Plastics, Alabama, USA under the following names: KWR101-150, KWR102-8812 BLK, KWR102, KWR105-7525, KWR-105M2, and KWR105M4.

[0041] The polyethylene composition includes (B) a polyethylene enhancer. As used herein, a "polyethylene enhancer" is an ethylene-based polymer from the group of single-site catalyzed linear low-density polyethylenes, including both linear and substantially linear low-density resins (m-LLDPE), ethylene-based plastomers (POP), and ethylene-based elastomers (POE). The polyethylene enhancer is (i) an ethylene-based polymer having a viscosity of 0.880 g / cm 3 ~0.900g / cm 3 (ii) a melt index of 0.3 g / 10 min to less than 1.0 g / 10 min, or 0.5 g / 10 min to 0.85 g / 10 min, and (iii) an I of 5.5 to 8.0 10 / I2 value.

[0042] The polyethylene composition (interchangeably referred to as the "composition") comprises: (A) 40% by weight to 70% by weight of high-density polyethylene post-consumer resin (HDPE-PCR); (B) 60% to 30% by weight of a polyethylene enhancer, (i) a density between 0.88 g / cc and 0.90 g / cc, and / or (ii) a melt index of 0.5 g / 10 min to 0.85 g / 10 min, and / or (iii) I of 5.5 to 8.0 10 a polyethylene enhancer having a / I value; (C) The polyethylene composition (1) a density between 0.910 g / cc and 0.935 g / cc, and / or (2) A melt index of 0.5 g / 10 min to 0.85 g / 10 min.

[0043] In one embodiment, the polyethylene composition comprises: (A) 40% by weight to 70% by weight, or 42% by weight to 65% by weight, or 42% by weight to 60% by weight of HDPE-PCR, (i) 0.950 g / cm 3~0.970g / cm 3 , or 0.955g / cm 3 ~0.970g / cm 3 density of, and / or (ii) HDPE-PCR having a melt index of 0.2 g / 10 min to 2.0 g / 10 min, or 0.3 g / 10 min to 1.0 g / 10 min; (B) 60% to 30%, or 58% to 35%, or 58% to 40% by weight of a polyethylene enhancer, wherein the polyethylene enhancer is an ethylene / C4-C8 α-olefin copolymer; (i) 0.880 g / cm 3 ~0.900g / cm 3 , or 0.882 g / cm 3 ~0.898g / cm 3 density of, and / or (ii) a melt index of from 0.3 g / 10 min to less than 1.0 g / 10 min, or from 0.5 g / 10 min to 0.85 g / 10 min, and / or (iii) I of 5.5 to 8.0 or 6.0 to 8.0 10 a polyethylene enhancer having a / I value; The polyethylene composition is (1) a density between 0.910 g / cc and 0.935 g / cc, and / or (2) It has a melt index (I2) in the range of 0.5 g / 10 min to 0.85 g / 10 min in units of g / 10 min (hereinafter referred to as composition 1).

[0044] The polyethylene composition is subjected to a devolatilization procedure to reduce or eliminate its limonene content. The polyethylene composition has a limonene content of less than 4 ppm, or 0 ppm, or from greater than 0 ppm to less than 4 ppm, or from 0.1 ppm to 3 ppm, or from 0.5 ppm to 2.5 ppm.

[0045] In one embodiment, Composition 1 has a limonene content of less than 4 ppm, or from 0 ppm to less than 4 ppm, or from 0.1 ppm to less than 3 ppm, or from 0.5 ppm to 2.5 ppm.

[0046] The polyethylene composition may contain one or more optional additives. Non-limiting examples of suitable additives include, but are not limited to, antistatic agents, color enhancers, dyes, lubricants, fillers (e.g., TiO or CaCO), opacifiers, nucleating agents, processing aids, pigments, primary antioxidants, secondary antioxidants, UV stabilizers, antiblocking agents, slip agents, tackifiers, flame retardants, antimicrobial agents, odor reducers, antifungal agents, and combinations thereof. The polyethylene composition may contain 0.001 to 10 weight (wt) percent, or 0.01 wt% to 1 wt%, or 0.1 wt% to 0.5 wt% of such additives, by combined weight, based on the total weight of the polyethylene composition including such additives.

[0047] The present disclosure provides a film. In one embodiment, the film is comprised of a polyethylene composition. The polyethylene composition comprises: (A) 40% to 70% by weight of post-consumer recycled high-density polyethylene (PCR HDPE); (B) 60% to 30% by weight of a polyethylene enhancer, (i) density of 0.88 g / cc to 0.90 g / cc; (ii) a melt index of 0.5 g / 10 min to 0.85 g / 10 min, and (iii) I of 5.5 to 8.0 10 a polyethylene enhancer having an I2 value of (C) The polyethylene composition (1) Density of 0.910 g / cc to 0.935 g / cc, and (2) A melt index of 0.5 g / 10 min to 0.85 g / 10 min.

[0048] In one embodiment, the film is composed of Composition 1.

[0049] The film may be a blown film or a cast film. The film may be a monolayer film or one or more layers of a multilayer film.

[0050] In one embodiment, the film is a monolayer film. In a further embodiment, the film is a monolayer breathable film.

[0051] In one embodiment, the film is a layer of a multilayer film. The multilayer film may have 2, or 3, or 4, or 5, or 6, or 7, or 8, or 9, or 10, or 11 layers.

[0052] The films of the present disclosure can have a variety of thicknesses, hi one embodiment, the film is a breathable film, the breathable film having a thickness of 0.25 mil, or 0.5 mil, or 0.7 mil, or 1.0 mil to 1.75 mil, or 2.0 mil, or 4.0 mil, or 6.0 mil, or 8.0 mil, or 10 mil, or 15 mil.

[0053] It is understood that any of the foregoing films / layers can further comprise one or more additives. Non-limiting examples of suitable additives include antioxidants, UV stabilizers, heat stabilizers, slip agents, antiblocking agents, pigments or colorants, processing aids, crosslinking catalysts, flame retardants, fillers, and blowing agents. In one embodiment, the film comprises 0 wt. % total additives, based on the total weight of the film, or 0 wt. % or more, or 1 wt. % to 1.5 wt. %, or 2 wt. %, or 2.5 wt. %, or 3 wt. % total additives.

[0054] In one embodiment, a film comprises a layer formed from the polyethylene composition laminated to another film.

[0055] The film can be corona treated and / or printed (eg, reverse printed or front printed).

[0056] In one embodiment, the film is oriented uniaxially (eg, in the machine direction) or biaxially (eg, in the machine direction and cross direction).

[0057] In one embodiment, the film has a thickness of from 1.5 mils to 2.5 mils, or from 1.7 mils to 2.3 mils, or 2.0 mils. The film is composed of a polyethylene composition.

[0058] In one embodiment, the film is comprised of a polyethylene composition comprising: (A) 40% by weight to 70% by weight, or 42% by weight to 65% by weight, or 42% by weight to 60% by weight of HDPE-PCR, (i) 0.950 g / cm 3 ~0.970g / cm 3 , or 0.955g / cm 3 ~0.970g / cm 3 density of, and / or (ii) HDPE-PCR having a melt index of 0.2 g / 10 min to 2.0 g / 10 min, or 0.3 g / 10 min to 1.0 g / 10 min; (B) 60% to 30%, or 58% to 35%, or 58% to 40% by weight of a polyethylene enhancer, wherein the polyethylene enhancer is an ethylene / C4-C8 α-olefin copolymer; (i) 0.880 g / cm 3 ~0.900g / cm 3 , or 0.882 g / cm 3 ~0.898g / cm 3 density of, and / or (ii) a melt index of from 0.3 g / 10 min to less than 1.0 g / 10 min, or from 0.5 g / 10 min to 0.85 g / 10 min, and / or (iii) I of 5.5 to 8.0 or 6.0 to 8.0 10 a polyethylene enhancer having a / I value; The polyethylene composition is (1) a density between 0.910 g / cc and 0.935 g / cc, and / or (2) A melt index (I2) in g / 10 min of 0.5 g / 10 min to 0.85 g / 10 min (hereinafter referred to as Composition 1), and the film has the following properties: a machine direction tear strength of 450 gf to 900 gf, or 470 gf to 900 gf, or 480 gf to 900 gf, and / or a machine direction 2% secant modulus of 45,000 psi to 60,000 psi, or 47,000 psi to 60,000 psi, or 48,000 psi to 60,000 psi, and / or Dart impact strength of 600g to 1000g, or 620g to 990g, and / or a limonene content of less than 4 ppm, or 0 ppm, or between 0 ppm and 4 ppm, or between 0.1 ppm and 3 ppm, or between 0.5 ppm and 2.5 ppm; and / or 50.0mm 2 ~120mm 2 , or 55.0 mm 2 ~115mm 2 , or 58.0 mm 2 ~112mm 2 The defect size ranges from 400 μm to 800 μm.

[0059] By way of example, and not limitation, some embodiments of the present disclosure will now be described in detail in the following examples. [Example]

[0060] The materials used in the comparative samples (CS) and inventive examples (IE) are provided in Tables 1A and 1B below.

[0061] [Table 1]

[0062] A. High-density polyethylene-post-consumer resin (HDPE-PCR)

[0063] [Table 2]

[0064] B. Polyethylene Enhancers and Polymerization All raw materials (ethylene and 1-octene) and process solvents (high-purity narrow-boiling range isoparaffinic solvent, Isopar-E) are purified with molecular sieves before being introduced into the reaction environment. Hydrogen is supplied under pressure as a high-purity grade and is not further purified. The monomer feed stream to the reactor is pressurized above the reaction pressure via a mechanical compressor. The solvent and comonomer feeds are pressurized above the reaction pressure via pumps. The individual catalyst components are manually batch diluted with purified solvent and pressurized above the reaction pressure. All reaction feed streams are metered using mass flow meters and independently controlled by computer-automated valve control systems.

[0065] A single reactor system is used for Enhancer 1 and Enhancer A. The continuous solution polymerization reactor consists of a liquid-filled, non-adiabatic, isothermal circulating loop reactor that mimics a continuously stirred tank reactor (CSTR) with heat removal. Independent control of all fresh solvent, monomer, comonomer, hydrogen, and catalyst component feeds is possible. All fresh feed streams to the reactor (solvent, monomer, and hydrogen) are temperature controlled by passing the feed streams through heat exchangers. All fresh feed to the polymerization reactor is injected into the reactor at two locations, with approximately equal reactor volume between each injection location. The fresh feed is controlled with each injector receiving half of the total fresh feed mass flow.

[0066] The catalyst components are injected into the polymerization reactor through an injection stinger. The primary catalyst component feed is computer-controlled to maintain the reactor monomer conversion at a specified target value. The cocatalyst component is fed based on a calculated, specified molar ratio relative to the primary catalyst component. Immediately after the reactor feed injection point, the feed stream is mixed with the contents of a circulating polymerization reactor with static mixing elements. The reactor contents are continuously circulated through a heat exchanger, which serves to remove the majority of the heat of reaction, with the coolant side temperature serving to maintain an isothermal reaction environment at a specified temperature. Circulation around the reactor loop is provided by a pump.

[0067] The reactor effluent enters a zone where it is deactivated by addition and reaction with a suitable reagent (water). At this same reactor exit location, other additives are added for polymer stabilization. The additives are octadecyl 3,5-di-tert-butyl-4-hydroxyhydrocinnamate, tetrakis(methylene(3,5-di-tert-butyl-4-hydroxyhydrocinnamate))methane, and tris(2,4-di-tert-butyl-phenyl)phosphite.

[0068] Following catalyst deactivation and additive addition, the reactor effluent enters a devolatilization system where the ethylene / octene copolymer is removed from the non-polymer stream. The isolated ethylene / octene copolymer melt is pelletized and collected. The non-polymer stream passes through various equipment that separates most of the ethylene removed from the system. Most of the solvent and unreacted comonomer pass through a purification system before being recycled to the reactor. Small amounts of solvent and comonomer are purged from the process. The catalyst components and cocatalysts are provided in Table 2 below. Polymerization conditions for Enhancer 1 and Enhancer A are provided in Table 3 below.

[0069] Enhancer 2, Enhancer 3, Enhancer B, and Enhancer 4 are prepared according to the following process: All raw materials (monomer and comonomer) and process solvent (high-purity narrow-boiling range isoparaffinic solvent, Isopar-E) are purified with molecular sieves before introduction into the reaction environment. Hydrogen is supplied under pressure as a high-purity grade and is not further purified. The monomer feed stream to the reactor is pressurized above the reaction pressure via a mechanical compressor. The solvent feed is pressurized above the reaction pressure via a pump. The comonomer feed is pressurized above the reaction pressure via a pump. The individual catalyst components are manually batch diluted with purified solvent and pressurized above the reaction pressure via individual pumps. All reaction feed streams except the catalyst components are metered using mass flow meters and independently controlled by computer-automated valve control systems. The catalyst components are metered using mass flow meters and independently controlled by computer-automated metering pumps.

[0070] The reactor configuration is either a continuous solution polymerization reactor consisting of a liquid-filled, non-adiabatic, isothermal circulating loop reactor (loop reactor) with heat removal, or a continuous solution polymerization reactor consisting of a liquid-filled, adiabatic, continuous stirred tank reactor (CSTR). The reactor configuration used for Enhancer 2, Enhancer 3, Enhancer B, and Enhancer 4 is shown in Figure 1.

[0071] The loop reactor configuration allows for independent control of all fresh solvent, monomer, comonomer (if present), hydrogen, and catalyst component feeds. All fresh feed streams to each reactor (solvent, monomer, comonomer (if present), and hydrogen) are temperature-controlled, typically between 15 and 50°C, to maintain a single solution phase by passing the feeds through heat exchangers. All fresh feeds are injected into the reactor at two locations, with approximately equal reactor volume between each injection location. Fresh feeds are controlled with each injector receiving half of the total fresh feed mass flow. Catalyst components are injected into the polymerization reactor separately from the other feeds. The primary catalyst component feed is computer-controlled to maintain reactor monomer conversion at a specific value. Cocatalyst components are fed based on a calculated, specified molar ratio relative to the primary catalyst component. Immediately after each feed injection location, the feed streams are mixed with the circulating polymerization reactor contents with static mixing elements. The contents of the loop reactor are continuously circulated through a heat exchanger, which serves to remove most of the heat of reaction, with the coolant side serving to maintain an isothermal reaction environment at a specified temperature. Circulation around the first reactor loop is effected by a pump.

[0072] The CSTR configuration allows for independent control of all fresh solvent, monomer, comonomer (if present), hydrogen, and catalyst component feeds. All fresh feed streams to each reactor (solvent, monomer, comonomer [if present], and hydrogen) are temperature-controlled, typically between 15 and 50°C, to maintain a single solution phase by passing the feeds through heat exchangers. All fresh feeds are injected into the reactor at a single point. Catalyst components are injected into the polymerization reactor separately from the other feeds. Primary catalyst component feed is computer-controlled to maintain reactor monomer conversion at a specific value. Cocatalyst components are fed based on a calculated, specified molar ratio to the primary catalyst component. Agitators within the reactor provide continuous mixing of the reactants. An oil bath provides some fine adjustment of reactor temperature control.

[0073] In both reactor configurations, the reactor effluent enters a zone where it is deactivated by addition and reaction with a suitable reagent (typically water). At the outlet of this same reactor, other additives are added for polymer stabilization (typical antioxidants suitable for stabilization during extrusion and fabrication, such as octadecyl 3,5-di-tert-butyl-4-hydroxyhydrocinnamate, tetrakis(methylene(3,5-di-tert-butyl-4-hydroxyhydrocinnamate))methane, and tris(2,4-di-tert-butyl-phenyl)phosphite, and optionally acid scavengers, such as calcium stearate).

[0074] Following catalyst deactivation and additive addition, the reactor effluent enters a devolatilization system where the polymer is removed from the non-polymer stream. The isolated polymer melt is pelletized and collected. The non-polymer stream is removed from the system.

[0075] The catalyst components and cocatalysts are provided in Table 2 below.

[0076] [Table 3]

[0077] The polymerization conditions for enhancer 1 and enhancer A are provided below in Table 3. The polymerization conditions for enhancer 2, enhancer 3, enhancer B, and enhancer 4 are provided below in Table 3B.

[0078] [Table 4]

[0079] [Table 5]

[0080] The properties of the polyethylene enhancer ("enhancer") are provided in Table 4 below.

[0081] [Table 6]

[0082] C. Polyethylene Composition The individual pellet components were fed into a hopper using a gravimetric feeder. The gravimetric feeder fed the resin formulation into a Labtech LTE20-32 twin-screw extruder at a rate of 15 lb / h. From the extruder, the resin formulation was conveyed to a blown film die. The LTE feed throat was set at 193°C, and the remaining barrel, conveying section, and die temperatures were set and maintained at 215°C. Monolayer blown films with a target thickness of 2 mil were produced from a blown film line with a 2-inch die diameter and a 1.0 mm die gap. To produce the film, an output rate of 2.4 lb / h / in was targeted for the die circumference, using pressurized ambient air to expand the film bubble to a blow-up ratio of 2.5. A dual-lip air ring driven by a variable-speed blower was used for all experiments. The frost line height (FLH) was maintained between 9.3 and 10.3 inches. Film thickness was targeted at 2 mil and controlled within ±10% by adjusting the nip roller speed. The film is wound into a roll. Properties of the inventive and comparative films are provided below in Table 5. The defect counts in Table 5 range from 400 μm to 800 μm. The weight percentages in Table 5 are based on the total weight of the film.

[0083] [Table 7] *ND - Not Detected

[0084] The compositions (IE) IE1, IE2, IE3, and IE4 of the present invention each provide an unexpected balance of mechanical properties (good dart, tear, and secant modulus), low defect counts, and bubble stability suitable for blown film applications. IE1-IE4 each have improved mechanical properties compared to the comparative samples (CS), particularly compared to PCR-containing CS4, CS5, CS6, CS7, CS8, and CS9. IE1-IE4 exhibit dart impact strengths of 630-1044 g compared to PCR-containing CS4-CS6 and CS9 (CS7 and CS8 contain more than 60 wt.% enhancer, based on the total weight of the film), which have dart impact strengths of 194 g-491 g. IE1-IE4 each exhibit a dart impact strength of 1320 mm compared to the CS3 film made from PCR Avangard 100 (1320 mm defect count). 2 ) has a lower number of defects (59.7 mm 2 ~110mm 2 IE1-IE4 each contain PCR-HDPE, and each unexpectedly exhibits a MI of less than 1.0 g / 10 min, which provides good bubble stability for blown films compared to PCR-based stretched films such as Avangard 100 (MI 1.8 g / 10 min).

[0085] The present disclosure is not limited to the embodiments and examples contained herein, but is specifically intended to include portions of the embodiments and modifications of those embodiments, including combinations of elements of different embodiments, to the extent that they fall within the scope of the following claims.

Claims

1. 1. A composition comprising: (A) 40% to 70% by weight of high-density polyethylene post-consumer resin (HDPE-PCR); (B) 60% to 30% by weight of a polyethylene enhancer, (i) a density of 0.88 g / cc to 0.90 g / cc; (ii) a melt index of 0.5 g / 10 min to 0.85 g / 10 min; and (iii) I of 5.5 to 8.0 １０ / I ２ a polyethylene enhancer having a value of (C) the composition is (1) a density of 0.910 g / cc to 0.935 g / cc; and (2) A composition having a melt index of 0.5 g / 10 min to 0.85 g / 10 min.

2. 10. The composition of claim 1, wherein the composition has a limonene content of less than 4 ppm.

3. A film, (A) 40% to 70% by weight of post-consumer recycled high-density polyethylene (PCR HDPE); (B) 60% to 30% by weight of a polyethylene enhancer, (i) a density of 0.88 g / cc to 0.90 g / cc; (ii) a melt index of 0.5 g / 10 min to 0.85 g / 10 min; and (iii) I of 5.5 to 8.0 １０ / I ２ a polyethylene enhancer having a value of (C) the film is (1) a density of 0.0910 g / cc to 0.935 g / cc; and (2) A film having a melt index of 0.5 g / 10 min to 0.85 g / 10 min.

4. 4. The film of claim 3, wherein the film has a limonene content of less than 4 ppm.

5. The film is 50.0 mm ２ ~120mm ２ 5. The film of claim 3, wherein the number of defects is:

6. The film is Machine direction tear strength of 450 gf to 900 gf; a machine direction 2% secant modulus of 45,000 psi to 60,000 psi; Dart impact strength of 600g to 1000g, and 6. The film of claim 3, having a property selected from the group consisting of: , and a combination thereof.

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