BACKGROUND

[0001] Cables, such as power cables or communication cables, are a type of conductor which include an inner conducting element such as a metal wire ora glass fiber, and one or more outer layers for shielding and protecting purposes. The outermost coating, or outermost layer, of the cable is a protective layer typically referred to as the outer sheath or outer jacket. The coating that directly contacts the inner conducting element is typically referred to as an insulation layer.

[0002] Known is ethylene-based polymer containing fillers for the manufacture of cable jackets and insulation layers to enable good thermal conductivity. However, conventional fillers are generally known to decrease the Alternating Current Breakdown Strength (ACBD) of the layer.

[0003] The art recognizes the need to provide a composition containing ethylene-based polymer for use in cable jacket and cable insulation applications that exhibits suitable ACBD in combination with suitable thermal conductivity.

SUMMARY

[0004] The present disclosure provides a coated conductor. The coated conductor includes a conductor and a coating on the conductor. The coating contains (A) an ethylene-based polymer and (B) from 1.0 wt% to 8 wt% graphene nanoflakes having (i) from 1 to 50 layers and (ii) a surface area less than 500 m2/g.

BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Figure 1 is a cross-sectional view of a coated conductor in accordance with an embodiment of the present disclosure.

DEFINITIONS

[0006] Any reference to the Periodic Table of Elements is that as published by CRC Press, Inc., 1990-1991. Reference to a group of elements in this table is by the new notation for numbering groups.

[0007] 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 its equivalent US version is so incorporated by reference) especially with respect to the disclosure of definitions (to the extent not inconsistent with any definitions specifically provided in this disclosure) and general knowledge in the art. [0008] The numerical ranges disclosed herein include all values from, and including, the lower and upper value. For ranges containing explicit values (e.g., a range from 1, or 2, or 3 to 5, or 6, or 7), any subrange between any two explicit values is included (e.g., the range 1-7 above includes subranges 1 to 2; 2 to 6; 5 to 7; 3 to 7; 5 to 6; etc.).

[0009] Unless stated to the contrary, implicit from the context, or customary in the art, all parts and percents are based on weight and all test methods are current as of the filing date of this disclosure.

[0010] An "all-dielectric self-supporting cable" or "ADSS cable" is an optical fiber cable that is capable of supporting itself between external structures (such as utility poles) without using conductive metal support elements within the cable. ADSS cable may be installed along existing overhead transmission lines, and can share the same external structures as electrical conductors (such as high voltage power lines).

[0011] The terms "blend" or "polymer blend," as used herein, is a blend of two or more polymers. Such a blend may or may not be miscible (not phase separated at molecular level). Such a blend may or may not be phase separated. Such 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.

[0012] The term "block copolymer" or "segmented copolymer" refers to a polymer comprising two or more chemically distinct regions or segments (referred to as "blocks") joined in a linear manner, that is, a polymer comprising chemically differentiated units which are joined (covalently bonded) end-to-end with respect to polymerized functionality, rather than in pendent or grafted fashion. In an embodiment, the blocks differ in the amount or type of comonomer incorporated therein, the density, the amount of crystallinity, the type of crystallinity (e.g. polyethylene versus polypropylene), the crystallite size attributable to a polymer of such composition, the type or degree of tacticity (isotactic or syndiotactic), regio- regularity or regio-irregularity, the amount of branching, including long chain branching or hyper-branching, the homogeneity, or any other chemical or physical property.

[0013] The term "composition" refers to a mixture of materials which comprise the composition, as well as reaction products and decomposition products formed from the materials of the composition.

[0014] The terms "comprising," "including," "having" and their derivatives, are not intended to exclude the presence of any additional component, step or procedure, whether or not the same is specifically disclosed. In order to avoid any doubt, all compositions claimed through 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 succeeding recitation any other component, step, or procedure, excepting 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," unless stated otherwise, refers to the listed members individually as well as in any combination. Use of the singular includes use of the plural and vice versa.

[0015] A "conductor" is one or more wire(s), or one or more fiber(s), for conducting heat, light, and/or electricity. The conductor may be a single-wire/fiber or a multi-wire/fiber and may be in strand form or in tubular form. Non-limiting examples of suitable conductors include carbon and various metals, such as silver, gold, copper, and aluminum. The conductor may also be optical fiber made from either glass or plastic. The conductor may or may not be disposed in a protective sheath. A "cable" is a conductor whereby two or more wires, or two or more optical fibers, are bound together, optionally in a common insulation covering. The individual wires or fibers inside the covering may be bare, covered, or insulated. Typical cable designs are illustrated in USP 5,246,783; 6,496,629; and 6,714,707. Combination cables may contain both electrical wires and optical fibers. The cable can be designed for low, medium, and/or high voltage applications.

[0016] "Crosslinkable" and "curable" indicate that a polymer, before or after shaped into an article, is not cured or crosslinked and has not been subjected or exposed to treatment that has induced substantial crosslinking even though the polymer may comprise additive(s) or functionality that will effectuate substantial crosslinking upon subjection or exposure to such treatment (e.g., exposure to heat). Crosslin kability of a polymer, composition, or coating may be assessed by testing in a Moving Die Rheometer (MDR) at elevated temperatures, and measuring the changes in elastic torque.

[0017] "Crosslinked" and similar terms indicate that a polymer composition or coating, before or after it is shaped into an article, has xylene or decalin extractables of less than or equal to 90 weight percent (i.e., greater than or equal to 10 weight percent gel content).

[0018] "Cured" and similar terms indicate that a polymer, before or after it is shaped into an article, was subjected or exposed to a treatment which induced crosslinking.

[0019] An "ethylene-based polymer" is a polymer that contains more than 50 weight percent polymerized ethylene monomer (based on the total amount of polymerizable monomers) and, optionally, may contain at least one comonomer. Ethylene-based polymer includes ethylene homopolymer, and ethylene copolymer (meaning units derived from ethylene and one or more comonomers). The terms "ethylene-based polymer" and "polyethylene" may be used interchangeably. Nonlimiting examples of ethylene-based polymer (polyethylene) include low density polyethylene (LDPE), medium density polyethylene (MDPE), and linear polyethylene. Nonlimiting examples of linear polyethylene include linear low density polyethylene (LLDPE), ultra low density polyethylene (ULDPE), very low density polyethylene (VLDPE), multi-component ethylene-based copolymer (EPE), ethylene/a-olefin multi-block copolymers (also known as olefin block copolymer (OBC)), single-site catalyzed linear low density polyethylene (m-LLDPE), substantially linear, or linear, plastomers/elastomers, and high density polyethylene (HDPE). Generally, polyethylene may be produced in gas-phase, fluidized bed reactors, liquid phase slurry process reactors, or liquid phase solution process reactors, using a heterogeneous catalyst system, such as Ziegler-Natta catalyst, a homogeneous catalyst system, comprising Group 4 transition metals and ligand structures such as metallocene, non metallocene metal-centered, heteroaryl, heterovalent aryloxyether, phosphinimine, and others. Combinations of heterogeneous and/or homogeneous catalysts also may be used in either single reactor or dual reactor configurations. In an embodiment, the ethylene-based polymer does not contain an aromatic comonomer polymerized therein.

[0020] "Ethylene plastomers/elastomers" are substantially linear, or linear, ethylene/a- olefin copolymers containing homogeneous short-chain branching distribution comprising units derived from ethylene and units derived from at least one C3-C10 a-olefin comonomer, or at least one C4-C8 a-olefin comonomer, or at least one C ₆ -Cs a-olefin comonomer. Ethylene plastomers/elastomers have a density from 0.870 g/cc to 0.917 g/cc. Nonlimiting examples of ethylene plastomers/elastomers include AFFINITY™ plastomers and elastomers (available from The Dow Chemical Company), EXACT™ Plastomers (available from ExxonMobil Chemical), Tafmer™ (available from Mitsui), Nexlene™ (available from SK Chemicals Co.), and Lucene™ (available LG Chem Ltd.).

[0021] "High density polyethylene" (or "HDPE") is an ethylene homopolymer or an ethylene/a-olefin copolymer with at least one C4-C10 a-olefin comonomer, or C4-C8 a-olefin comonomer and a density from greater than 0.94 g/cc to 0.98 g/cc. The HDPE can be a monomodal copolymer or a multimodal copolymer. A "monomodal ethylene copolymer" is an ethylene/C4-Cio a-olefin copolymer that has one distinct peak in a gel permeation chromatography (GPC) showing the molecular weight distribution. A "multimodal ethylene copolymer" is an ethylene/C4-Cio a-olefin copolymer that has at least two distinct peaks in a GPC showing the molecular weight distribution. Multimodal includes copolymer having two peaks (bimodal) as well as copolymer having more than two peaks. Nonlimiting examples of HDPE include DOW™ High Density Polyethylene (HDPE) Resins, ELITE™ Enhanced Polyethylene Resins, and CONTINUUM™ Bimodal Polyethylene Resins, each available from The Dow Chemical Company; LUPOLEN™, available from LyondellBasell; and HDPE products from Borealis, Ineos, and ExxonMobil.

[0022] An "interpolymer" is a polymer prepared by the polymerization of at least two different monomers. This generic term includes copolymers, usually employed to refer to polymers prepared from two different monomers, and polymers prepared from more than two different monomers, e.g., terpolymers, tetrapolymers, etc.

[0023] A "jacket" is a coating on the conductor.

[0024] "Linear low density polyethylene" (or "LLDPE") is a linear ethylene/a-olefin copolymer containing heterogeneous short-chain branching distribution comprising units derived from ethylene and units derived from at least one C3-Cioa-olefin comonomer or at least one C4-C8 a-olefin comonomer, or at least one C ₆ -Cs a-olefin comonomer. LLDPE is characterized by little, if any, long chain branching, in contrast to conventional LDPE. LLDPE has a density from 0.910 g/cc to 0.940 g/cc. Nonlimiting examples of LLDPE include TUFLIN™ linear low density polyethylene resins and DOWLEX™ polyethylene resins, each available from the Dow Chemical Company; and MARLEX™ polyethylene (available from Chevron Phillips).

[0025] "Low density polyethylene" (or "LDPE") consists of ethylene homopolymer, or ethylene/a-olefin copolymer comprising at least one C3-C10 a-olefin, preferably C3-C4 that has a density from 0.915 g/cc to 0.940 g/cc and contains long chain branching with broad MWD. LDPE is typically produced by way of high pressure free radical polymerization (tubular reactor or autoclave with free radical initiator). Nonlimiting examples of LDPE include MarFlex™ (Chevron Phillips), LUPOLEN™ (LyondellBasell), as well as LDPE products from Borealis, Ineos, ExxonMobil, and others.

[0026] "Medium density polyethylene" (or "MDPE") is an ethylene homopolymer, or an ethylene/a-olefin copolymer comprising at least one C3-C10 a-olefin, or a C3-C4 a-olefin, that has a density from 0.926 g/cc to 0.940 g/cc. [0027] "Multi-component ethylene-based copolymer" (or "EPE") comprises units derived from ethylene and units derived from at least one C3-C10 a-olefin comonomer, or at least one C4-C8 a-olefin comonomer, or at least one C ₆ -Cs a-olefin comonomer, such as described in patent references USP 6,111,023; USP 5,677,383; and USP 6,984,695. EPE resins have a density from 0.905 g/cc to 0.962 g/cc. Nonlimiting examples of EPE resins include ELITE™ enhanced polyethylene and ELITE AT™ advanced technology resins, each available from The Dow Chemical Company; SURPASS™ Polyethylene (PE) Resins, available from Nova Chemicals; and SMART™, available from SK Chemicals Co.

[0028] An "olefin-based polymer," as used herein is a polymer that contains more than 50 mole percent polymerized olefin monomer (based on total amount of polymerizable monomers), and optionally, may contain at least one comonomer. Nonlimiting examples of olefin-based polymer include ethylene-based polymer and propylene-based polymer.

[0029] A "polymer" is a compound prepared by polymerizing monomers, whether of the same or a different type, that in polymerized form provide the multiple and/or repeating "units" or "mer units" that make up a polymer. The generic term polymer thus embraces the term homopolymer, usually employed to refer to polymers prepared from only one type of monomer, and the term copolymer, usually employed to refer to polymers prepared from at least two types of monomers. It also embraces all forms of copolymer, e.g., random, block, etc. The terms "ethylene/a-olefin polymer" and "propylene/a-olefin polymer" are indicative of copolymer as described above prepared from polymerizing ethylene or propylene respectively and one or more additional, polymerizable a-olefin monomer. It is noted that although a polymer is often referred to as being "made of" one or more specified monomers, "based on" a specified monomer or monomer type, "containing" a specified monomer content, or the like, in this context the term "monomer" is understood to be referring to the polymerized remnant of the specified monomer and not to the unpolymerized species. In general, polymers herein are referred to as being based on "units" that are the polymerized form of a corresponding monomer.

[0030] 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, optionally, may contain at least one comonomer. Propylene-based polymer includes propylene homopolymer, and propylene copolymer (meaning units derived from propylene and one or more comonomers). The terms "propylene-based polymer" and "polypropylene" may be used interchangeably. A nonlimiting example of a propylene-based polymer (polypropylene) is a propylene/a-olefin copolymer with at least one C2 or C4-C10 a-olefin comonomer.

[0031] "Single-site catalyzed linear low density polyethylenes" (or "m-LLDPE") are linear ethylene/a-olefin copolymers containing homogeneous short-chain branching distribution comprising units derived from ethylene and units derived from at least one C3-C10 a-olefin comonomer, or at least one C4-C8 a-olefin comonomer, or at least one C ₆ -Cs a-olefin comonomer. m-LLDPE has density from 0.913 g/cc to 0.940 g/cc. Nonlimiting examples of m- LLDPE include EXCEED™ metallocene PE (available from ExxonMobil Chemical), LUFLEXEN™ m- LLDPE (available from LyondellBasell), and ELTEX™ PF m-LLDPE (available from Ineos Olefins & Polymers).

[0032] "Ultra low density polyethylene" (or "ULDPE") and "very low density polyethylene" (or "VLDPE") each is a linear ethylene/a-olefin copolymer containing heterogeneous short-chain branching distribution comprising units derived from ethylene and units derived from at least one C3-C10 a-olefin comonomer, or at least one C4-C8 a-olefin comonomer, or at least one Ce- C ₈ a-olefin comonomer. ULDPE and VLDPE each has a density from 0.885 g/cc to 0.915 g/cc. Nonlimiting examples of ULDPE and VLDPE include ATTANE™ ULDPE resins and FLEXOMER™ VLDPE resins, each available from The Dow Chemical Company.

TEST METHODS

[0033] Alternating Current Breakdown Strength (also known as AC breakdown, or ACBD) is measured in accordance with ASTM D149 using a Hipotronics AC Breakdown Tester. Samples are compression molded at 180°C into a 40 mil (1.0 mm) plaque prior to testing.

[0034] Ash content and moisture content of the graphene nanoflakes are measured by thermogravimetric analysis (TGA).

[0035] Carbon content and oxygen content of the graphene nanoflakes are obtained from X-Ray Photoelectron Spectroscopy (XPS) and Energy Dispersive X-ray Spectroscopy (EDS) analysis. The Carbon/Oxygen Ratio is calculated as a ratio using the carbon content and the oxygen content.

[0036] Density of the coating is measured in accordance with ASTM D792, with values reported in grams per cubic centimeter (g/cc or g/cm ³ ). Samples are compression molded at 180°C into plaque discs with a 75 mil (1.9 mm) thickness and a 1 inch (25.4 mm) diameter prior to testing.

[0037] Density of the ethylene-based polymer is measured in accordance with ASTM D792, with values reported in grams per cubic centimeter (g/cc or g/cm ³ ).

[0038] Direct Current Conductivity (DC Conductivity) is measured on a custom designed version of the commercially available TF1000 from AixACCT, Germany. Testing is carried out at a temperature of 70°C and a DC electric stress of 30 kV/mm. DC conductivity is measured 3 hours after the electric stress is applied. The result is reported in femtosiemens per meter (fS/m).

[0039] The number of layers in the graphene nanoflakes are measured using Raman spectroscopy. Raman spectra generated using visible light (e.g., 532 nm wavelength light, or 2.33 eV energy) with peaks around wavenumber 1580 cm ¹ (corresponding to G band), 1300 cm ¹ (corresponding to D band), and 2700 cm ¹ (second order peak, 2D band) are analyzed as discussed in Journal of Raman Spectroscopy 2009, 40, 1931; Physical Review Letters 2006, 97, 187401; and in Journal of Physics: Conference Series 2008, 109, 012008 to characterize the thickness of graphene nanoflakes.

[0040] Melt index is measured at 190°C under a load of 2.16 kg according to ASTM D1238, and is reported in grams eluted per 10 minutes (g/10 min).

[0041] Shore A Hardness is measured in accordance with ASTM D2240 - 05.

[0042] Shore D Hardness is measured in accordance with ASTM D2240 - 05.

[0043] Specific gravity of the graphene nanoflakes is measured in accordance with ASTM D4439, with values reported in grams per cubic centimeter (g/cc or g/cm ³ ).

[0044] Surface area (BET surface area) of the graphene nanoflakes is measured in accordance with ASTM D6556-10.

[0045] Thermal conductivity is measured in accordance with ISO Standard 22007-2 using a Hot Disk TPS 2500 S apparatus. Samples are compression molded at 180°C into a 300 mil (7.6 mm) plaque prior to testing. The hot disk sensor is placed between two samples (in a solid form), such that no air gaps are present between the hot disk sensor and the samples. The apparatus supplies a known amount of energy to the initially isothermal sample via the hot disk sensor, and then measures the resulting temperature increase using the hot disk sensor as a thermometer.

[0046] Vicat softening point is measured in accordance with ASTM D1525.

[0047] Volume resistivity (p) is measured using a Hewlett-Packard 4329A High Resistance Meter and a 16008A Resistivity cell. The materials are compression molded at 180°C into a 50 mil (1.27 mm) plaque and cut into a circle with a 3.5 inch (8.89 cm) diameter. The thickness of the sample (t) is measured prior to conducting electrical testing. Volume resistance (VR) is measured by placing the circular samples between electrodes. A 500 V DC voltage is applied to the specimen for 20 seconds, and then volume resistance is measured after 60 seconds. Volume resistivity is calculated using volume resistance and specimen dimensions using the following Equation (A):

VR p = 19.6 — Equation (A).

Average Width, Average Thickness, and Aspect Ratio

[0048] The average width and the average thickness of the graphene nanoflakes is calculated from the arithmetic average of the measured width and measured thickness values, respectively, often arbitrary crystallites taken from a scanning electron microscope (SEM) photo of the graphene nanoflakes.

[0049] The aspect ratio is calculated in accordance with the following Equation (B):

, . average width _ .

Aspect Ratio = - average thickness Equation (B).

Differential Scanning Calorimetry (DSC)

[0050] Differential Scanning Calorimetry (DSC) can be used to measure the melting, crystallization, and glass transition behavior of a polymer over a wide range of temperature. For example, the TA Instruments Q1000 DSC, equipped with an RCS (refrigerated cooling system) and an autosampler is used to perform this analysis. During testing, a nitrogen purge gas flow of 50 ml/min was used. Each sample is melt pressed into a thin film at 190°C; the melted sample is then air-cooled to room temperature (25°C). A 3-10 mg, 6 mm diameter specimen is extracted from the cooled polymer, weighed, placed in a light aluminum pan (50 mg), and crimped shut. Analysis is then performed to determine its thermal properties.

[0051] The thermal behavior of the sample is determined by ramping the sample temperature up and down to create a heat flow versus temperature profile. First, the sample is rapidly heated to 180°Cand held isothermal for 3 minutes in order to remove its thermal history. Next, the sample is cooled to -80°C at a 10°C/minute cooling rate and held isothermal at -80°C for 3 minutes. The sample is then heated to 180°C (this is the "second heat" ramp) at a 10°C/minute heating rate. The cooling and second heating curves are recorded. The values determined are extrapolated onset of melting, T _m , and extrapolated onset of crystallization, T _c . [0052] Melting point, T _m , is determined from the DSC heating curve by first drawing the baseline between the start and end of the melting transition. A tangent line is then drawn to the data on the low temperature side of the melting peak. Where this line intersects the baseline is the extrapolated onset of melting (T _m ). This is as described in Bernhard Wunderlich, The Basis of Thermal Analysis, in Thermal Characterization of Polymeric Materials 92, 277-278 (Edith A. Turi ed., 2d ed. 1997).

[0053] Crystallization temperature, Tc, is determined from a DSC cooling curve as above except the tangent line is drawn on the high temperature side of the crystallization peak. Where this tangent intersects the baseline is the extrapolated onset of crystallization (Tc).

DETAILED DESCRIPTION

[0054] The present disclosure provides a coated conductor. The coated conductor includes a conductor and a coating on the conductor. The coating includes (A) an ethylene-based polymer and (B) from 1.0 wt% to 8 wt% graphene nanoflakes having (i) from 1 to 50 layers and (ii) a surface area less than 500 m ² /g- i. Conductor

[0055] The coated conductor includes a conductor. The conductor may be a single wire/fiber or a multi-wire/fiber and may be in strand form or in tubular form. Non-limiting examples of suitable conductors include carbon and various metals, such as silver, gold, copper, and aluminum. The conductor may also be optical fiber made from either glass or plastic. The conductor may or may not be disposed in a protective sheath.

[0056] In an embodiment, the conductor is a non-metal conductor. A "non-metal conductor" is a conductor that is void of, or substantially void of, metal. The non-metal conductor may be a single-wire/fiber or a multi-wire/fiber and may be in strand form or in tubular form. Non-limiting examples of suitable non-metal conductors include optical fiber made from either glass or plastic. The non-metal conductor may or may not be disposed in a protective sheath.

[0057] In an embodiment, the conductor is a cable. A "cable" is a conductor whereby two or more wires, or two or more optical fibers, are bound together, optionally in a common insulation covering. The individual wires or fibers inside the covering may be bare, covered, or insulated. Combination cables may contain both electrical wires and optical fibers. The cable can be designed for low, medium, and/or high voltage applications. In an embodiment, the cable, and further the coated conductor, excludes electrical wires.

[0058] The conductor may comprise two or more embodiments disclosed herein. ii. Coating

[0059] The coated conductor includes a coating on the conductor. The coating contains (A) an ethylene-based polymer and (B) from 1.0 wt% to 8 wt% graphene nanoflakes having (i) from 1 to 50 layers and (ii) a surface area less than 500 m ² /g.

A. Ethylene-Based Polymer

[0060] The coating contains an ethylene-based polymer.

[0061] The ethylene-based polymer can be any ethylene-based polymer disclosed herein. [0062] In an embodiment, the ethylene-based polymer is an ethylene/a-olefin copolymer. Nonlimiting examples of suitable ethylene/a-olefin copolymer include LDPE, MDPE, and linear polyethylene. Nonlimiting examples of linear polyethylene include LLDPE, ULDPE, VLDPE, EPE, ethylene/a-olefin multi-block copolymers (also known as OBC), m-LLDPE, substantially linear, or linear, plastomers/elastomers (POP), and combinations thereof.

[0063] In an embodiment, the ethylene-based polymer is selected from MDPE, VLDPE, HDPE, LLDPE, and combinations thereof.

[0064] The ethylene/a-olefin copolymer contains, consists essentially of, or consists of (i) ethylene and (ii) C ₆ -Cs a-olefin comonomer. In an embodiment, the a-olefin comonomer is selected from hexene and octene. In a further embodiment, the a-olefin is octene.

[0065] In an embodiment, the ethylene/a-olefin copolymer contains (i) from greater than 50 wt%, or 60 wt%, or 65 wt% to 80 wt%, or 90 wt% units derived from ethylene; and (ii) a reciprocal amount of units derived from C ₆ -Cs a-olefin comonomer, or from 10 wt%, or 20 wt% to 35 wt%, or 40 wt%, or less than 50 wt% units derived from C ₆ -Cs a-olefin comonomer, based on the total weight of the ethylene/a-olefin copolymer.

[0066] In an embodiment, the ethylene/a-olefin copolymer is a MDPE having one, or both of the following properties: (i) a density from 0.926 g/cc, or 0.930 g/cc to 0.935 g/cc, or 0.940 g/cc; and/or (ii) a melt index from 0.1 g/10 min, or 0.5 g/10 min, or 0.8 g/10 min to 0.9 g/10 min, or 1.0 g/10 min, or 2.0 g/10 min, or 5.0 g/10 min, or 10 g/10 min, or 20 g/10 min.

[0067] In an embodiment, the ethylene/a-olefin copolymer is a VLDPE having one, some, or all of the following properties: (i) a density from 0.885 g/cc, or 0.900 g/cc to 0.905 g/cc, or 0.910 g/cc, or 0.915 g/cc; and/or (ii) a melt index from 0.1 g/10 min, or 0.5 g/10 min to 1.0 g/10 min, or 5.0 g/10 min, or 10 g/10 min, or 20 g/10 min; and/or (iii) a melting temperature, Tm, from 90°C, or 100°C, or 110°C, or 115°C to 120°C, or 125°C, or 130°C; and/or (iv) a Shore A hardness from 80, or 85, or 90 to 95, or 100; and/or (v) a Vicat softening temperature from 75°C, or 80°C, or 85°C to 90°C, or 95°C, or 100°C, or 110°C.

[0068] In an embodiment, the ethylene/a-olefin copolymer is a LLDPE having one, some, or all of the following properties: (i) a density from 0.910 g/cc, or 0.915 g/cc, or 0.920 g/cc to 0.925 g/cc, or 0.930 g/cc, or 0.935 g/cc, or 0.940 g/cc; and/or (ii) a melt index from 1 g/10 min, or 5 g/10 min, or 10 g/10 min, or 15 g/10 min, or 20 g/10 min to 25 g/10 min, or 30 g/10 min, or 40 g/10 min, or 50 g/10 min; and/or (iii) a melting temperature, Tm, from 90°C, or 100°C, or 110°C, or 115°C, or 120°C to 125°C, or 130°C; and/or (iv) a crystallization temperature, Tc, from 80°C, or 90°C, or 100°C, or 105°C to 110°C, or 115°C, or 120°C; and/or (v) a Vicat softening temperature from 80°C, or 85°C, or 90°C to 95°C, or 100°C, or 110°C, or 115°C; and/or (vi) a Shore D hardness from 40, or 45, or 50 to 55, or 60, or 65, or 70.

[0069] In an embodiment, the ethylene/a-olefin copolymer is a HDPE having one, some, or all of the following properties: (i) a density from 0.94 g/cc, or 0.945 g/cc to 0.95 g/cc, or 0.98 g/cc; and/or (ii) a melt index from 0.5 g/10 min, or 0.8 g/10 min, or 1 g/10 min, or 5 g/10 min, or 10 g/10 min to 15 g/10 min, or 20 g/10 min, or 30 g/10 min; and/or (iii) a Vicat softening temperature from 100°C, or 110°C, or 120°C, or 125°Cto 130°C, or 140°C.

[0070] In an embodiment, the ethylene/a-olefin copolymer is a LDPE having one, some, or all of the following properties: (i) a density from 0.915 g/cc, or 0.920 g/cc, or 0.921 g/cc to 0.925 g/cc, or 0.930 g/cc, or 0.940 g/cc; and/or (ii) a melt index from 1 g/10 min, or 10 g/10 min, or 20 g/10 min, or 30 g/10 min, or 35 g/10 min to 38 g/10 min, or 40 g/10 min, or 50 g/10 min; and/or (iii) a Vicat softening temperature from 60°C, or70°C, or80°C, or85°C to 86°C, or90°C, or 100°C; and/or (iv) a Shore D from 30, or 35, or 40, or 41 to 45, or 50, or 55, or 60.

[0071] The ethylene/a-olefin copolymer may be a functionalized ethylene/a-olefin copolymer. A "functionalized ethylene/a-olefin copolymer" is an ethylene/a-olefin copolymer with a carboxylic acid-based moiety bonded to the ethylene/a-olefin copolymer chain (for example, a carboxylic acid-based moiety grafted to an ethylene/a-olefin copolymer chain). A "carboxylic acid-based moiety" is a compound that contains a carboxyl group (— COOH) or a derivative thereof. Nonlimiting examples of suitable carboxylic acid-based moieties include carboxylic acids and carboxylic acid anhydrides. Nonlimiting examples of suitable carboxylic acids and carboxylic acid anhydrides include maleic acid, fumaric acid, itaconic acid, acrylic acid, methacrylic acid, crotonic acid, maleic anhydride, and itaconic anhydride. The base ethylene/a- olefin copolymer of the functionalized ethylene/a-olefin copolymer may be any ethylene/a- olefin copolymer disclosed herein.

[0072] In an embodiment, the ethylene-based polymer is selected from MDPE, VLDPE, LLDPE, HDPE, LDPE, and combinations thereof. [0073] In an embodiment, the ethylene-based polymer is a blend containing, consisting essentially of, or consisting of MDPE, VLDPE, LLDPE, and HDPE.

[0074] In an embodiment, the ethylene-based polymer is a blend containing, consisting essentially of, or consisting of MDPE and LDPE.

[0075] In an embodiment, the ethylene-based polymer is a blend containing, consisting essentially of, or consisting of HDPE and LDPE.

[0076] In an embodiment, the ethylene-based polymer consists of LDPE.

[0077] The ethylene-based polymer may comprise two or more embodiments disclosed herein.

B. Graphene Nanoflakes

[0078] The coating contains from 1.0 wt% to 8 wt% graphene nanoflakes having (i) from 1 to 50 layers and (ii) a surface area less than 500 m ² /g.

[0079] A "graphene nanoflake" is a graphene with from 1 to 50 layers. Graphene nanoflakes may be present as isolated particles or as relatively loosely stacked agglomerates. [0080] "Graphene" is an allotrope of carbon in the form of a two-dimensional, atomic-scale, hexagonal lattice in which one carbon atom forms each vertex. Graphene is structurally distinct from, and excludes, other allotropes of carbon such as diamond, graphite (including expanded graphite and flake graphite), lonsdaleite, buckminsterfullerene, fullerite, amorphous carbon, and carbon nanotubes.

[0081] The graphene nanoflakes have from 1 to 50 layers, or from 1 to 40 layers, or from 1 to 20 layers, or from 1 to 15 layers.

[0082] The graphene nanoflakes have a surface area less than 500 m ² /g; or less than 450 m ² /g; or equal to, or less than 400 m ² /g; or less than 300 m ² /g; or less than 200 m ² /g; or equal to, or less than 150 m ² /g; or less than 50 m ² /g. In an embodiment, the graphene nanoflakes have a surface area from 20 m ² /g, or 25 m ² /g, or 30 m ² /g to 50 m ² /g, or 100 m ² /g, or 150 m ² /g, or 200 m ² /g, or 300 m ² /g, or 400 m ² /g, or 450 m ² /g, or less than 500 m ² /g. In a further embodiment, the graphene nanoflakes have a surface area from 20 m ² /g to less than 500 m ² /g, or from 30 m ² /g to 400 m ² /g, or from 20 m ² /g to 150 m ² /g, or from 20 m ² /g to 50 m ² /g, or from 100 m ² /g to 150 m ² /g, or from 100 m ² /g to 400 m ² /g, or from 300 m ² /g to 500 m ² /g.

[0083] In an embodiment, the graphene nanoflakes have an average thickness from 2 nm, or 3 nm to 6 nm, or 10 nm. In another embodiment, the graphene nanoflakes have an average thickness from 2 nm to 10 nm, or from 3 nm to 6 nm. [0084] In an embodiment, the graphene nanoflakes have an average flake size (also referred to as an average width) from 1 pm, or 3 pm to 38 pm, or 40 pm, or 50 pm, or 80 pm, or 100 pm. In another embodiment, the graphene nanoflakes have an average flake size from 1 pm to 100 pm, or from 1 pm to 50 pm, or from 1 pm to 40 pm, or from 1 pm to 38 pm. [0085] In an embodiment, the graphene nanoflakes have a specific gravity of 2.2 g/cc.

[0086] In an embodiment, the graphene nanoflakes have an aspect ratio from 100:1, or

300:1, or 500:1 to 750:1, or 2,500:1, or 8,000:1, or 13,000:1, or 15,000:1, ,or 20,000:1, or 40,000:1, or 50,000:1. In another embodiment, the graphene nanoflakes have an aspect ratio from 100:1 to 50,000:1, or from 500:1 to 20,000:1, or from 500:1 to 15,000:1, or from 500:1 to 750:1, or from 7,600:1 to 12,667:1, or from 500:1 to 2,500:1.

[0087] In an embodiment, the graphene nanoflakes have one, some, or all, of the following properties: (i) a carbon content from 91 wt%, or 93 wt% to 100 wt%; and/or (ii) an oxygen content from 0 wt% to 4 wt%, or 7 wt%; and/or (iii) an ash content from 0 wt% to 3 wt%, or 7 wt%; and/or (iv) a moisture content from 0 wt% to 0.5 wt%, or 0.7 wt%, based on the total weight of the graphene nanoflakes; and/or (v) a Carbon/Oxygen Ratio greater than 10:1.

[0088] The graphene nanoflakes have from 1 to 50 layers, or from 1 to 40 layers, or from 1 to 20 layers, or from 1 to 15 layers; and a surface area from 20 m ² /g to less than 500 m ² /g, or from 30 m ² /g to 400 m ² /g, or from 20 m ² /g to 150 m ² /g, or from 20 m ² /g to 50 m ² /g, or from 100 m ² /g to 150 m ² /g, or from 100 m ² /g to 400 m ² /g, or from 300 m ² /g to 500 m ² /g. In an embodiment, the graphene nanoflakes have one, some, or all, of the following properties: (i) an average thickness from 2 nm to 10 nm, or from 3 nm to 6 nm; and/or (ii) an average flake size from 1 pm to 100 pm, or from 1 pm to 50 pm, or from 1 pm to 40 pm, or from 1 pm to 38 pm; and/or (iii) a specific gravity of 2.2 g/cc; and/or (iv) an aspect ratio from 100:1 to 50,000:1, or from 500:1 to 20,000:1, or from 500:1 to 15,000:1, or from 500:1 to 750:1, or from 7,600:1 to 12,667:1, or from 500:1 to 2,500:1; and/or (v) a carbon content from 91 wt%, or 93 wt% to 100 wt%; and/or (vi) an oxygen content from 0 wt% to 4 wt%, or 7 wt%; and/or (vii) an ash content from 0 wt% to 3 wt%, or 7 wt%; and/or (viii) a moisture content from 0 wt% to 0.5 wt%, or 0.7 wt%, based on the total weight of the graphene nanoflakes; and/or (ix) a Carbon/Oxygen Ratio greater than 10:1, or greater than 13:1, or greater than 18:1, or greater than 23:1, or greater than 100:1. Nonlimiting examples of suitable graphene nanoflakes include heXo-G V4, heXo-G V20, and GRAPHENEBLACK 3X, each available from NanoXplore.

[0089] The graphene nanoflakes are not surface modified. For example, the graphene nanoflakes are not coated with a fatty acid and/or a silane surface treatment agent.

[0090] The graphene nanoflakes may comprise two or more embodiments disclosed herein.

C. Optional Additive

[0091] In an embodiment, the coating includes (A) the ethylene-based polymer, (B) the graphene nanoflakes, and (C) one or more optional additives.

[0092] Nonlimiting examples of suitable additives include carbon black, antioxidants, colorants, ultra violet (UV) absorbers or stabilizers, heat stabilizers, anti-blocking agents, flame retardants, compatibilizers, plasticizers, fillers, processing aids, crosslinking agents, and combinations thereof.

[0093] In an embodiment, the coating contains carbon black. A nonlimiting example of a suitable carbon black is DFNC-0037 BK, available from The Dow Chemical Company. In an embodiment, the coating contains from 0.9 wt%, or 1 wt%, or 2 wt% to 3 wt%, or 5 wt%, or 7 wt%, or 9 wt%, or 10 wt% carbon black; or from 0.9 wt% to 10 wt%, or from 0.9 wt% to 5.0 wt%, or from 0.9 wt% to 2.6 wt% carbon black, based on the total weight of the coating.

[0094] In an embodiment, the coating is void of, or substantially void of, carbon black.

[0095] In an embodiment, the coating contains an antioxidant. Nonlimiting examples of suitable antioxidants include phenolic antioxidants, thio-based antioxidants, phosphate-based antioxidants, and hydrazine-based metal deactivators. In an embodiment, the coating contains an antioxidant, such as IRGANOX 1010, IRGANOX 1035, IRGANOX 1024, CHIMASSORB 944, CYANOX 2212, and/or 4,4'-thiobis(2-t-butyl-5-methylphenol) (TBM-6) in an amount from 0.05 wt%, or 0.1 wt%, or 0.5 wt%, or 1.0 wt% to 1.5 wt%, or 2.0 wt%, or 3.0 wt%, based on the total weight of the coating.

[0096] In an embodiment, the coating contains a UV stabilizer. A nonlimiting example of a suitable stabilizer is a hindered amine light stabilizer. In an embodiment, the coating contains from 0.1 wt%, or 0.2 wt% to 0.3 wt%, or 0.4 wt%, or 0.5 wt% stabilizer, based on the total weight of the coating.

[0097] In an embodiment, the coating contains a filler. Nonlimiting examples of suitable fillers include zinc oxide, zinc borate, zinc molybdate, zinc sulfide, organo-clay, and combinations thereof. The filler may or may not have flame retardant properties.

[0098] In an embodiment, the coating contains a processing aid. Nonlimiting examples of suitable processing aids include oils, organic acids (such as stearic acid), metal salts of organic acids (such as zinc stearate), and fluorinated polymers. In a further embodiment, the coating contains a processing aid in an amount from 0.01 wt%, or 0.02 wt% to 0.05 wt%, or 0.10 wt%, based on total weight of the coating.

[0099] In an embodiment, the coating contains a compatibilizer. Nonlimiting examples of suitable compatibilizers include ethylene-vinyl acetate (EVA) copolymer, ethylene-ethyl acrylate (EEA) copolymer, functionalized polyolefins, and combination thereof. In an embodiment, the coating contains from 2 wt%, or 3 wt% to 5 wt%, or 8 wt% compatibilizer, based on the total weight of the coating.

[00100] In an embodiment, the coating is void of, or substantially void of, compatibilizer.

[00101] In an embodiment, the coating contains a crosslinking agent. A nonlimiting example of a suitable crosslinking agent is an organic peroxide, such as dicumyl peroxide.

[00102] In an embodiment, the coating contains an additive selected from carbon black, an antioxidant, a stabilizer, a processing aid, a crosslinking agent, and combinations thereof. In another embodiment, the coating contains an additive selected from carbon black, an antioxidant, and combinations thereof. In another embodiment, the coating contains an additive selected from an antioxidant, a crosslinking agent, and combinations thereof.

[00103] In an embodiment, the coating is void of, or substantially void of, diamond, graphite (including expanded graphite and flake graphite), lonsdaleite, buckminsterfullerene, fullerite, amorphous carbon, and/or carbon nanotubes.

[00104] In an embodiment, the coating is void of, or substantially void of, propylene-based polymer.

[00105] In an embodiment, the coating is void of, or substantially void of, functionalized ethylene-based polymer.

[00106] In an embodiment, the coating is void of, or substantially void of, polysiloxane.

[00107] In an embodiment, the coating is void of, or substantially void of, metal hydroxide.

[00108] In an embodiment, the ethylene-based polymer and the antioxidant are the only polymeric compounds present in the coating. In another embodiment, the ethylene-based polymer is the only polymeric compound present in the coating.

[00109] In an embodiment, the ethylene-based polymer is the only compound containing ethylene monomer that is present in the coating.

[00110] The optional additive may comprise two or more embodiments disclosed herein. [00111] In an embodiment, the coating contains, consists essentially of, or consists of (A) the ethylene-based polymer, (B) the graphene nanoflakes, and (C) one or more optional additives. [00112] In an embodiment, the coating contains from 25 wt%, or 50 wt%, or 58 wt%, or 60 wt%, or 65 wt%, or 70 wt%, or 75 wt%, or 80 wt%, or 85 wt%, or 90 wt% to 95 wt%, or 98 wt%, or 99 wt% ethylene-based polymer, based on the total weight of the coating. In another embodiment, the coating contains from 25.0 wt% to 99 wt%, or from 65 wt% to 99 wt%, or from 90 wt% to 99 wt% ethylene-based polymer, based on the total weight of the coating.

[00113] In an embodiment, the coating contains (i) from 30 wt%, or 35 wt%, or 40 wt% to 50 wt%, or 55 wt%, or 65 wt%, or 75 wt% MDPE; (ii) from 5 wt%, or 10 wt%, or 13 wt%, or 15 wt% to 20 wt%, or 25 wt%, or 30 wt% VLDPE; (iii) from 0.5 wt%, or 1 wt%, or 2 wt%, or 3 wt% to 4 wt%, or 5 wt%, or 10 wt% LLDPE; and (iv) from 1 wt%, or 4 wt%, or 5 wt% to 10 wt%, or 15 wt%, or 20 wt%, or 25 wt%, or 30 wt%, or 40 wt% HDPE, based on the total weight of the coating. [00114] In an embodiment, the coating contains (i) from 30 wt%, or 35 wt%, or 40 wt% to 50 wt%, or 55 wt%, or 65 wt%, or 70 wt%, or 80 wt%, or 90 wt%, or 97 wt% MDPE; and (ii) from 1 wt%, or 2 wt%, or 3 wt% to 7 wt%, or 10 wt% LDPE, based on the total weight of the coating. [00115] In an embodiment, the coating contains (i) from 30 wt%, or 35 wt%, or 40 wt% to 50 wt%, or 55 wt%, or 65 wt%, or 70 wt%, or 80 wt%, or 90 wt%, or 97 wt% HDPE; and (ii) from 1 wt%, or 2 wt%, or 3 wt% to 7 wt%, or 10 wt% LDPE, based on the total weight of the coating. [00116] In an embodiment, the coating contains from 30 wt%, or 35 wt%, or 40 wt% to 50 wt%, or 55 wt%, or 65 wt%, or 70 wt%, or 80 wt%, or 90 wt%, or 99 wt% LDPE, based on the total weight of the coating.

[00117] The coating contains from 1 wt% to 8 wt% graphene nanoflakes, based on the total weight of the coating. In an embodiment, the coating contains from 1.0 wt%, or 1.5 wt%, or 2.0 wt% to3.0wt%, or 4.0 wt%, or5.0wt%, or 6.0 wt%, or 7.0 wt%, or 8.0 wt% graphene nanoflakes, based on the total weight of the coating. In another embodiment, the coating contains from 1.5 wt% to 8 wt%, or from 1.5 wt% to 7.0 wt%, or from 1.0 wt% to 7.0 wt%, or from 1.0 wt% to 2.0 wt%, or from 1.5 wt% to 5.0 wt% graphene nanoflakes, based on the total weight of the coating. Not wishing to be bound by any particular theory, it is believed that a graphene nanoflake loading greater than 8 wt% leads to agglomeration of the graphene nanoflakes and/or introduces structural defects such as microvoids in the coating, thereby increasing the electric field locally and resulting in a coating that has a lower AC breakdown strength.

[00118] In an embodiment, the coating contains from 0.4 vol%, or 0.6 vol%, or 0.8 vol% to 1.3 vol%, or 2.1 vol%, or 3.0 vol%, or 3.6 vol% graphene nanoflakes; or from 0.4 vol%to 3.6 vol%, or from 0.4 vol% to 3.0 vol%, or 0.6 vol% to 2.1 vol%, or from 0.4 vol% to 0.8 vol% graphene nanoflakes, based on the total volume of the coating.

[00119] In an embodiment, the coating contains, consists essentially of, or consists of: (A) from 25.0 wt% to 99 wt%, or from 65 wt% to 99 wt%, or from 90 wt% to 99 wt% ethylene- based polymer; (B) from 1.5 wt% to 8 wt%, or from 1.5 wt% to 7.0 wt%, or from 1.0 wt% to 7.0 wt%, or from 1.0 wt% to 2.0 wt%, or from 1.5 wt% to 5.0 wt% graphene nanoflakes; (C) optionally, from 0.9 wt% to 10 wt%, or from 0.9 wt% to 5.0 wt%, or from 0.9 wt% to 2.6 wt% carbon black; and (D) optionally, from 0.05 wt% to 3.0 wt%, or from 1.0 wt% to 2.0 wt% antioxidant, based on the total weight of the coating.

[00120] In an embodiment, the coating has an AC breakdown strength (ACBD) equal to, or greater than, 35 kV/mm; or equal to, or greater than, 42 kV/mm; or equal to, or greater than, 44 kV/mm. In another embodiment, the coating has an ACBD from 35 kV/mm, or 36 kV/mm, or 42 kV/mm, or 44 kV/mm, or 45 kV/mm to 46 kV/mm, or 50 kV/mm, or 60 kV/mm. In another embodiment, the coating has an ACBD from 35 kV/mm to 60 kV/mm, or from 35 kV/mm to 50 kV/mm, or from 36 kV/mm to 40 kV/mm, or from 42 kV/mm to 60 kV/mm, or from 45 kV/mm to 51 kV/mm, or from 44 kV/mm to 60 kV/mm, or from 45 kV/mm to 46 kV/mm.

[00121] In an embodiment, the coating has a volume resistivity greater than, or equal to, 1.0 x 10 ¹⁷ ohm*cm; or greater than, or equal to, 1.5 x 10 ¹⁷ ohm*cm; or greater than, or equal to, 2.0 x 10 ¹⁷ ohm*cm. In another embodiment, the coating has a volume resistivity from 1.0 x 10 ¹⁷ ohm*cm, or 2.5 x 10 ¹⁷ ohm*cm, or 10 x 10 ¹⁷ ohm*cm to 20 x 10 ¹⁷ ohm*cm, or 25 x 10 ¹⁷ ohm*cm, or 30 x 10 ¹⁷ ohm*cm. In a further embodiment, the coating has a volume resistivity from 1.0 x 10 ¹⁷ ohm*cm to 30 x 10 ¹⁷ ohm*cm, or from 2.5 x 10 ¹⁷ ohm*cm to 30 x 10 ¹⁷ ohm*cm. [00122] In an embodiment, the coating has a density from 0.85 g/cc, or 0.90 g/cc, or 0.94 g/cc to 0.980 g/cc, or 0.985 g/cc, or 0.990 g/cc, or 0.995 g/cc, or 1.00 g/cc, or 1.10 g/cc, or 1.15 g/cc, or 1.20 g/cc. In another embodiment, the coating has a density from 0.85 g/cc to 1.20 g/cc, or from 0.94 g/cc to 1.00 g/cc, or from 0.94 g/cc to 0.980 g/cc.

[00123] In an embodiment, the coating has a thermal conductivity greater than 0.40 W-rrr ¹ -K ¹ , or greater than 0.41 W-m ^_1 -K ^_1 , or greater than 0.42 W-m ^_1 ·K ^_1 . In an embodiment, the coating has a thermal conductivity from 0.40 W-m ^_1 -K ^_1 , or 0.41 W-m ^_1 -K ^_1 , or 0.42 W-m ^_1 -K ^_1 , or 0.43 W-m ^_1 -K ¹ to 0.66 W-m ^K ¹ , or 0.70 W-m ^K ¹ , or 0.75 W-m ^K ¹ , or 0.80 W-m ^K ¹ . In an embodiment, the coating has a thermal conductivity from greater than 0.40 W-m ^_1 -K ¹ to 0.80 W-m ^_1 -K ^_1 , or from 0.40 W-m ^_1 -K ¹ to 0.70 W-m ^_1 -K ^_1 , or from 0.40 W-m ^_1 -K ¹ to 0.66 W-m ^_1 -K ^_1 , or from 0.43 W-m ^K ¹ to 0.80 W-m ^K ¹ .

[00124] In an embodiment, the coating has a DC Conductivity from 0.1 fS/m, or 1 fS/m, or 5 fS/m, or 10 fS/m, or 14 fS/m to 54 fS/m, or 55 fS/m, or 56 fS/m, or 58 fS/m. In another embodiment, the coating has a DC Conductivity from 0.1 fS/m to 58 fS/m, or from 1 fS/m to 56 fS/m, or from 5 fS/m to 55 fS/m, or from 14 fS/m to 54 fS/m.

[00125] The (B) graphene nanoflakes are independently and uniformly dispersed throughout the (A) ethylene-based polymer matrix.

[00126] The coating may or may not be crosslinked. In an embodiment, the coating is not crosslinked and/or is not crosslinkable.

[00127] In an embodiment, the coating is crosslinked. In an embodiment, crosslinking of the present coating begins in the extruder, but only to a minimal extent. In another embodiment, crosslinking is delayed until the coating is extruded upon the conductor. Crosslinking of the present coating can be initiated and/or accelerated through the application of heat or radiation. In an embodiment, after extrusion, the coated conductor is conditioned at a temperature from 160°C, or 180°C to 200°C, or 400°C in a continuous vulcanization tube.

[00128] In an embodiment, the coating contains, consists essentially of, or consists of: (A) from 25.0 wt% to 99 wt%, or from 65 wt% to 99 wt%, or from 90 wt% to 99 wt% ethylene- based polymer; (B) from 1.5 wt% to 8 wt%, or from 1.5 wt% to 7.0 wt%, or from 1.0 wt% to 7.0 wt%, or from 1.0 wt% to 2.0 wt%, or from 1.5 wt% to 5.0 wt% graphene nanoflakes; (C) optionally, from 0.9 wt% to 10 wt%, or from 0.9 wt% to 5.0 wt%, or from 0.9 wt% to 2.6 wt% carbon black; and (D) optionally, from 0.05 wt% to 3.0 wt%, or from 1.0 wt% to 2.0 wt% antioxidant, based on the total weight of the coating. The graphene nanoflakes have from 1 to 50 layers, or from 1 to 40 layers, or from 1 to 20 layers, or from 1 to 15 layers; and a surface area from 20 m ² /g to less than 500 m ² /g, or from 20 m ² /g to 400 m ² /g, or from 30 m ² /g to 400 m ² /g, or from 20 m ² /g to 150 m ² /g, or from 20 m ² /g to 50 m ² /g, or from 100 m ² /g to 150 m ² /g, or from 100 m ² /g to 400 m ² /g, or from 300 m ² /g to 500 m ² /g. The coating has one, some, or all of the following properties: (i) contains from 0.4 vol% to 3.6 vol%, or from 0.4 vol% to 3.0 vol%, or 0.6 vol% to 2.1 vol%, or from 0.4 vol% to 0.8 vol% graphene nanoflakes, based on the total volume of the coating; and/or (ii) an ACBD from 35 kV/mm to 60 kV/mm, or from 35 kV/mm to 50 kV/mm, or from 36 kV/mm to 40 kV/mm, or from 42 kV/mm to 60 kV/mm, or from 45 kV/mm to 51 kV/mm, or from 44 kV/mm to 60 kV/mm, or from 45 kV/mm to 46 kV/mm; and/or (iii) a volume resistivity from 1.0 x 10 ¹⁷ ohm*cm to 30 x 10 ¹⁷ ohm*cm, or from 2.0 x 10 ¹⁷ ohm*cm to 30 x 10 ¹⁷ ohm*cm, or from 2.5 x 10 ¹⁷ ohm*cm to 30 x 10 ¹⁷ ohm*cm; and/or (iv) a density from 0.85 g/cc to 1.20 g/cc, or from 0.94 g/cc to 1.00 g/cc, or from 0.94 g/cc to 0.980 g/cc; and/or (v) a thermal conductivity from greater than 0.40 W-m ^_1 ·K ¹ to 0.80 W-rn ^K ¹ , or from 0.40 W-rn ^K ¹ to 0.70 W-rn ^K ¹ , or from 0.40 W-m ^_1 ·K ¹ to 0.66 W-rn ^K ¹ , or from 0.43 W-m ^_1 ·K ¹ to 0.80 W-m ¹ -K ¹ ; and/or (vi) a DC Conductivity from 0.1 fS/m to 58 fS/m, or from 1 fS/m to 56 fS/m, or from 5 fS/m to 55 fS/m, or from 14 fS/m to 54 fS/m.

[00129] It is understood that the sum of the components in each of the coatings disclosed herein, including the foregoing coating, yields 100 wt%.

[00130] The coating may comprise two or more embodiments disclosed herein.

[00131] The coating may be formed by way of melt blending. "Melt blending" is a process whereby at least two components are combined or otherwise mixed together, and at least one of the components is in a melted state. The melt blending may be accomplished by way of batch mixing, extrusion blending, extrusion molding, and any combination thereof.

[00132] In an embodiment, the coating is extruded over the conductor. The extruder has a crosshead die, which provides the desired layer (wall or coating) thickness. A nonlimiting example of an extruder, which can be used is the single screw type modified with a crosshead die, cooling trough and continuous take-up equipment. A typical single screw type extruder can be described as one having a hopper at its upstream end and a die at its downstream end. The hopper feeds into the barrel, which contains a screw. At the downstream end, between the end of the screw and the die are a screen pack and a breaker plate. The screw portion of the extruder is considered to be divided up into three sections, the feed section, the compression section, and the metering section, and multiple heating zones from the rear heating zone to the front heating zone with the multiple sections running from upstream to downstream. The length to diameter ratio of the barrel is in the range of 16:1 to 25:1, or 30:1. Grooved barrel extruders or twin screw extruders can also be employed in the core coating process. The jacketing extrusion process can take place at temperatures in the range from 160°C, or 180°C, or 200°C to 210°C, or 220°C, or 240°C, or 260°C. The crosshead die distributes the coating composition in a flow channel such that the melted coating composition exits with a uniform velocity and is applied to the conductor. In this way, the blending (melt blending) and the extrusion are performed in the same, single extruder. The conductor passes through the center of the crosshead, and as it exits, a uniform layer of the coating is circumferentially applied using either pressure, or semi pressure of tube-on tooling. One or more layers of the coating (or other material) can be applied using a multiple crosshead. The coated conductor is then cooled in a water trough sufficiently to prevent deformation of the applied coating layer on the take-up reel, yielding a coated conductor.

[00133] Melt blending may occur sequentially before the extrusion. Alternatively, melt blending may occur simultaneously, or substantially simultaneously, with the extrusion (i.e., melt blending and extrusion occurring in the same extruder). The carbon black may be added during the melt blending and/or during the extrusion.

[00134] In an embodiment, the coating is an outermost coating on the conductor. An "outermost coating" is a layer with an outer surface that is exposed to, or substantially exposed to, ambient environment. The coating may be the sole component surrounding the conductor. Alternatively, the coating may be the outermost layer of a multilayer jacket or a multilayer sheath encasing the conductor.

[00135] In an embodiment, the coating directly contacts the conductor. The term "directly contacts," as used herein, is a coating configuration whereby the coating is located immediately adjacent to the conductor, the coating touches the conductor, and no intervening layers, no intervening coatings, and/or no intervening structures, are present between the coating and the conductor. In an embodiment, the coating is an insulation layer.

[00136] In another embodiment, the coating indirectly contacts the conductor. The term "indirectly contacts," as used herein, is a coating configuration whereby an intervening layer, an intervening coating, or an intervening structure, is present between the coating and the conductor. Nonlimiting examples of suitable intervening layers, intervening coatings, and intervening structures include insulation layers, moisture barrier layers, buffer tubes, and combinations thereof. In an embodiment, the coating is a jacket layer.

[00137] In an embodiment, an insulation layer directly contacts the conductor, and the outermost coating directly contacts the insulation layer. In other words, the coating directly contacts an insulation layer surrounding the conductor. Nonlimiting examples of suitable insulation layers include foamed insulation layers, thermoplastic insulation layers, crosslinked insulation layers, and combinations thereof.

[00138] In an embodiment, the coated conductor includes a plurality of non-metal conductors that are optical fibers, and the optical fibers are disposed in a buffer tube, the coating surrounding the buffer tube. The optical fibers may be disposed in a single buffer tube, or in a plurality of buffer tubes. [00139] The thickness of the coating depends on the cable application. In an embodiment, the coating has a thickness from 0.10 mm, or 0.25 mm to 0.50 mm, or 1.00 mm, or 2.00 mm, or 3.00 mm, or 4.00 mm, or 5.00 mm; or from 0.10 mm to 5.00 mm.

[00140] Figure l shows a nonlimiting example of a suitable coated conductor 10. The coated conductor 10 includes a conductor 1. An insulation layer 2 surrounds the conductor 1. The insulation layer 2 directly contacts the conductor 1. The conductor 1 extends through the insulation layer 2. An outermost layer 3 surrounds the insulation layer 2. The outermost layer 3 directly contacts the insulation layer 2.

[00141] In an embodiment, the outermost layer 3 contains the present coating.

[00142] In an embodiment, the insulation layer 2 contains the present coating.

[00143] In an embodiment, the coated conductor is void of, or substantially void of, metal.

[00144] In an embodiment, the coated conductor contains, consists essentially of, or consists of: a conductor and an outermost coating on the conductor, the outermost coating containing, consisting essentially of, or consisting of: (A) from 25.0 wt% to 99 wt%, or from 65 wt% to 99 wt%, or from 90 wt% to 99 wt% ethylene-based polymer; (B) from 1.5 wt% to 8 wt%, or from 1.5 wt% to 7.0 wt%, or from 1.0 wt% to 7.0 wt%, or from 1.0 wt% to 2.0 wt%, or from 1.5 wt% to 5.0 wt% graphene nanoflakes; (C) optionally, from 0.9 wt% to 10 wt%, or from 0.9 wt%to 5.0 wt%, or from 0.9 wt% to 2.6 wt% carbon black; and (D) optionally, from 0.05 wt% to 3.0 wt%, or from 1.0 wt% to 2.0 wt% antioxidant, based on the total weight of the coating. The graphene nanoflakes have from 1 to 50 layers, or from 1 to 40 layers, or from 1 to 20 layers, or from 1 to 15 layers; and a surface area from 20 m ² /g to less than 500 m ² /g, or from 30 m ² /g to 400 m ² /g, or from 20 m ² /g to 150 m ² /g, or from 20 m ² /g to 50 m ² /g, or from 100 m ² /g to 150 m ² /g, or from 100 m ² /g to 400 m ² /g, or from 300 m ² /g to 500 m ² /g. The coating has one, some, or all of the following properties: (i) contains from 0.4 vol% to 3.6 vol%, or from 0.4 vol% to 3.0 vol%, or 0.6 vol% to 2.1 vol%, or from 0.4 vol% to 0.8 vol% graphene nanoflakes, based on the total volume of the coating; and/or (ii) an ACBD from 35 kV/mm to 60 kV/mm, or from 35 kV/mm to 50 kV/mm, or from 36 kV/mm to 40 kV/mm; and/or (iii) a volume resistivity from 1.0 x 10 ¹⁷ ohm*cm to 30 x 10 ¹⁷ ohm*cm, or from 2.0 x 10 ¹⁷ ohm*cm to 30 x 10 ¹⁷ ohm*cm, or from 2.5 x 10 ¹⁷ ohm*cm to 30 x 10 ¹⁷ ohm*cm, or from 4.8 x 10 ¹⁷ ohm*cm to 30 x 10 ¹⁷ ohm*cm; and/or (iv) a density from 0.85 g/cc to 1.20 g/cc, or from 0.94 g/cc to 1.00 g/cc, or from 0.94 g/cc to 0.980 g/cc; and/or (v) a thermal conductivity from greater than 0.40 W-m ^_1 -K ¹ to 0.80 W-rrr^K ¹ , or from 0.40 W-m ^_1 -K ¹ to 0.70 W-m ^_1 -K ^_1 , or from 0.40 W-m ^_1 -K ¹ to 0.66 W-m ^_1 -K ^_1 , or from 0.43 W-m ^_1 ·K ¹ to 0.80 W-m ^_1 ·K ^_1 ; and/or (vi) a DC Conductivity from 0.1 fS/m to 58 fS/m, or from 1 fS/m to 56 fS/m, or from 5 fS/m to 55 fS/m, or from 14 fS/m to 54 fS/m. In an embodiment, the outermost coating is a jacket. In a further embodiment, the ethylene-based polymer is selected from MDPE, VLDPE, HDPE, LLDPE, and combinations thereof.

[00145] In an embodiment, the coated conductor contains, consists essentially of, or consists of: a conductor and a coating on the conductor, wherein the coating directly contacts the conductor. The coating is an insulation layer. The coating contains, consists essentially of, or consists of: (A) from 25.0 wt% to 99 wt%, or from 65 wt% to 99 wt%, or from 90 wt% to 99 wt% ethylene-based polymer; (B) from 1.5 wt% to 8 wt%, or from 1.5 wt% to 7.0 wt%, or from 1.0 wt% to 7.0 wt%, or from 1.0 wt% to 2.0 wt%, or from 1.5 wt% to 5.0 wt% graphene nanoflakes; (C) optionally, a crosslinking agent; and (D) optionally, from 0.05 wt% to 3.0 wt%, or from 1.0 wt%to 2.0 wt% antioxidant, based on the total weight of the coating. The graphene nanoflakes have from 1 to 50 layers, or from 1 to 40 layers, or from 1 to 20 layers, or from 1 to 15 layers; and a surface area from 20 m ² /g to less than 500 m ² /g, or from 20 m ² /g to 400 m ² /g, or from 30 m ² /g to 400 m ² /g, or from 20 m ² /g to 150 m ² /g, or from 20 m ² /g to 50 m ² /g, or from 100 m ² /g to 150 m ² /g, or from 100 m ² /g to 400 m ² /g, or from 300 m ² /g to 500 m ² /g. The coating has one, some, or all of the following properties: (i) contains from 0.4 vol% to 3.6 vol%, or from 0.4 vol% to 3.0 vol%, or 0.6 vol% to 2.1 vol%, or from 0.4 vol% to 0.8 vol% graphene nanoflakes, based on the total volume of the coating; and/or (ii) an ACBD from 42 kV/mm to 60 kV/mm, or from 45 kV/mm to 51 kV/mm, or from 44 kV/mm to 60 kV/mm, or from 45 kV/mm to 46 kV/mm; and/or (iii) a volume resistivity from 1.0 x 10 ¹⁷ ohm*cm to 30 x 10 ¹⁷ ohm*cm, or from 2.0 x 10 ¹⁷ ohm*cm to 30 x 10 ¹⁷ ohm*cm, or from 2.5 x 10 ¹⁷ ohm*cm to 30 x 10 ¹⁷ ohm*cm; and/or (iv) a density from 0.85 g/cc to 1.20 g/cc, or from 0.94 g/cc to 1.00 g/cc, or from 0.94 g/cc to 0.980 g/cc; and/or (v) a thermal conductivity from greater than 0.40 W-m ^_1 ·K ¹ to 0.80 W-m ^_1 ·K ^_1 , or from 0.40 W-m ^_1 -K ¹ to 0.70 W-m ^_1 -K ^_1 , or from 0.40 W-m ^_1 -K ¹ to 0.66 W-m ^_1 -K ^_1 , or from 0.43 W-m ^_1 -K ¹ to 0.80 W-m ^_1 -K ^_1 ; and/or (vi) a DC Conductivity from 0.1 fS/m to 58 fS/m, or from 1 fS/m to 56 fS/m, or from 5 fS/m to 55 fS/m, or from 14 fS/m to 54 fS/m. In an embodiment, the coated conductor includes a jacket layer in contact with the insulation layer.

[00146] In an embodiment, the coating that is an insulation layer is not crosslinked. In other words, the coating is void of, or substantially void of, crosslinking agent. The coating has an ACBD from 42 kV/mm to 60 kV/mm, or from 45 kV/mm to 51 kV/mm, or from 44 kV/mm to 60 kV/mm, or from 45 kV/mm to 46 kV/mm. In an embodiment, the ethylene-based polymer is selected from MDPE, HDPE, LDPE, and combinations thereof.

[00147] In an embodiment, the coating that is an insulation layer is crosslinked. In other words, the coating is formed from a composition containing a crosslinking agent (e.g., organic peroxide). The coating has an ACBD from 44 kV/mm to 60 kV/mm, or from 45 kV/mm to 46 kV/mm, or from 45 kV/mm to 51 kV/mm. In an embodiment, the ethylene-based polymer is LDPE.

[00148] In an embodiment, the coated conductor is selected from a fiber optic cable, a communications cable (such as a telephone cable or a local area network (LAN) cable), a power cable, wiring for consumer electronics, a power charger wire for cell phones and/or computers, computer data cords, power cords, appliance wiring material, home interior wiring material, consumer electronic accessory cords, and any combination thereof.

[00149] In an embodiment, the coating is an insulation layer of a high voltage power transmission cable or an extra high voltage power transmission cable.

[00150] In an embodiment, the coated conductor is an all-dielectric self-supporting (ADSS) cable. The ADSS cable is suitable for installation along a high voltage power line (having an operation voltage of at least 150 kV and/or a space potential of at least 4 kV in salty or polluted areas, as measured in accordance with IEEE 1222). The present ADSS cable in which no metal present in the coated conductor can advantageously be installed along a high-voltage power line without powering-down the lines.

[00151] The present coated conductor with a conductor and a coating containing (A) an ethylene-based polymer and (B) from 1.0 wt% to 8 wt% graphene nanoflakes having (i) from 1 to 50 layers and (ii) a surface area less than 500 m ² /g advantageously provides improved ACBD (i.e., at least 35 kV/mm), while maintaining a suitably high volume resistivity (i.e., at least 1.0 x 10 ¹⁷ ohm*cm).

[00152] By way of example, and not limitation, some embodiments of the present disclosure will now be described in detail in the following Examples.

EXAMPLES

[00153] The materials used in the inventive examples and in the comparative samples are provided in Table 1 below. Table 1. Starting materials for coatings [00154] The properties of the graphene nanoflakes used in the inventive examples and in the comparative samples are provided in Table 2 below.

Table 2

[00155] Graphene masterbatches are prepared by combining ethylene-based polymer with the graphene nanoflakes. The composition of each graphene masterbatch is provided in Table 3 below. Amounts in Table 3 are provided in weight percent, based on the total weight of the respective graphene masterbatch.

Table 3

[00156] CS 1 and Ex. 1-4 coating compositions are prepared in a Brabender mixing bowl. The DFH-3580H (MDPE) is first loaded into the bowl at 180°C. After the DFH-3580H is melted, FLEXOMER DFDA-1137 NT 7 (VLDPE) is added, followed by mixing for 3 minutes at a temperature of 180°C. Then, DFNC-0037 BK (carbon black masterbatch), graphene masterbatch, and the AO MB are added to the bowl and mixed for 5 minutes at a temperature of 180°C. The composition is cooled to room temperature (23-25°C), and then cut into pieces for extrusion. The CS 1 and Ex. 1-4 coating composition pieces are loaded into a 25:1 L/D Brabender Extruder equipped with a Maddock mixing screw with the conditions provided below in Table 4. The composition is fed through a 20/30/100/60/20 mesh screen pack at the end of the extruder. After exiting the extruder, the coating composition is cooled to room temperature (23-25°C) and pelletized. Tab e 4. Brabender Extruder Conditions

[00157] CS 2, CS 3 and Ex. 5-7 coating compositions are prepared in a Brabender mixing bowl. The components are loaded into the bowl and mixed for 5 minutes at a temperature of 140°C. The composition is cooled to room temperature (23-25°C).

[00158] Intermediate CS 4-6 and Ex. 9-11 coating compositions are prepared in a 7:1 L/D Brabender Twin Screw Extruder. The DXM-447 (LDPE), V4 LDPE MB (graphene masterbatch), and CYANOX 2212 (as a 3.6 wt% masterbatch in DXM-447) are loaded into the extruder with the conditions provided below in Table 5. The composition is fed through a 20/30/100/60/20 mesh screen pack at the end of the extruder. The composition is cooled to room temperature (23-25°C), and then cut into pellets for peroxide soaking. The intermediate CS 4-6 and Ex. 9- 11 coating composition pellets are preheated in a glass jar at 70°Cfor4 hours. Dicumyl peroxide is heated to 60°C (to a molded state) and sprayed onto the preheated pellets. The dicumyl peroxide is allowed to diffuse into the pellets at 70°C for at least 16 hours to yield the final CS 4- 6 and Ex. 9-11 coating compositions.

Tab e 5. Brabender Extruder Conditions

[00159] The coating composition and properties of each sample coating composition are provided in Table 6 below. Weight percent in Table 6 is based on the total weight of the respective coating composition.

[00160] As shown in Table 6, CS 1 is a coating composition containing (A) ethylene-based polymer (MDPE, VLDPE, and LLDPE), but no graphene nanoflakes. CS 1 exhibits an AC breakdown strength of less than 35 kV/mm (34 kV/mm).

[00161] In contrast, a coating composition (Ex. 1-4) containing (A) ethylene-based polymer (MDPE, VLDPE, and LLDPE) and (B) 1-8 wt% (1-7 wt%) graphene nanoflakes (heXo- G V20, heXo-G V4, or GRAPHENEBLACK 3X) having (i) 1-50 layers (6-40 layers) and (ii) a surface area less than 500 m ² /g (30-400 m ² /g) unexpectedly exhibits the combination of an AC breakdown strength of greater than 35 kV/mm (36-40 kV/mm), a volume resistivity greater than 1.0 x 10 ¹⁷ ohm*cm. Consequently, Ex. 1-4 is suitable for coated conductor applications, and for jacket layers in particular.

[00162] CS 2 and CS 3 are coating compositions containing (A) ethylene-based polymer (MDPE or HDPE), but no graphene nanoflakes. CS 2 and CS 3 each exhibits an AC breakdown strength of less than 42 kV/mm (41 kV/mm and 37 kV/mm, respectively).

[00163] In contrast, a coating composition (Ex. 5-7) containing (A) ethylene-based polymer (LDPE in combination with either MDPE or HDPE) and (B) 1-8 wt% (1-2 wt%) graphene nanoflakes (heXo-G V4) having (i) 1-50 layers (8-12 layers) and (ii) a surface area less than 500 m ² /g (100-150 m ² /g) unexpectedly exhibits the combination of an AC breakdown strength of greater than 42 kV/mm (45-51 kV/mm), a volume resistivity greater than 1.0 x 10 ¹⁷ ohm*cm. Consequently, Ex. 5-7 is suitable for non-crosslinked insulation layer applications, such as in DC cable applications.

Table 6

CS = comparative sample NM = not measured ^# vol% in Table 6 is based on the total volume of the respective coating composition

[00164] CS 4 is a coating composition containing (A) ethylene-based polymer (LDPE), but no graphene nanoflakes. CS 4 is a crosslinked coating composition. CS 4 exhibits an AC breakdown strength of less than 44 kV/mm (42 kV/mm).

[00165] CS 5 is a coating composition containing (A) ethylene-based polymer (LDPE) and (B) less than 1 wt% (0.8 wt%) graphene nanoflakes (heXo-G V4) having (i) 1-50 layers (8-12 layers) and (ii) a surface area less than 500 m ² /g (100-150 m ² /g). CS 5 is a crosslinked coating composition. CS 5 exhibits an AC breakdown strength of less than 44 kV/mm (43 kV/mm). [00166] CS 6 is a coating composition containing (A) ethylene-based polymer (LDPE) and (B) greater than 8 wt% (10 wt%) graphene nanoflakes (heXo-G V4) having (i) 1-50 layers (8- 12 layers) and (ii) a surface area less than 500 m ² /g (100-150 m ² /g). CS 6 is a crosslinked coating composition. CS 6 exhibits an AC breakdown strength of less than 44 kV/mm, and further less than 35 kV/mm (30 kV/mm).

[00167] In contrast, a coating composition (Ex. 9-11) containing (A) ethylene-based polymer (LDPE) and (B) 1-8 wt% (1.5-5.0 wt%) graphene nanoflakes (heXo-G V4) having (i) 1- 50 layers (8-12 layers) and (ii) a surface area less than 500 m ² /g (100-150 m ² /g) unexpectedly exhibits the combination of an AC breakdown strength of greater than 44 kV/mm (45-46 kV/mm), a volume resistivity greater than 1.0 x 10 ¹⁷ ohm»cm. Ex. 9-11 each is a crosslinked coating composition. Consequently, Ex. 9-11 is suitable for crosslinked insulation layer applications, such as AC cable applications.

[00168] It is specifically intended that the present disclosure not be limited to the embodiments and illustrations contained herein, but include modified forms of those embodiments including portions of the embodiments and combinations of elements of different embodiments as come with the scope of the following claims.