BACKGROUND

Field of the invention

[0001] The present disclosure generally relates polymeric compositions and more specifically to ultraviolet stabilized polymeric compositions.

Introduction

[0002] Submarine fiber optic cables are used in the transmission of data over long distances. Greater than 98 percent of data transmitted between continents is facilitated by the use of submarine fiber optic cables (“cables”). Cables physically link separate continents by being laid down on a seabed between the continents. Given the long distances between continents, the strength of signals passed through the cables would be diminished beyond recognition without the use of one or more repeaters. A cable repeater uses electrical energy to amplify the signal to mitigate signal loss. Typically, direct current power in the range of 10 kilovolts to 12 kilovolts is provided through an insulated and/or jacketed conductor within the cable, but there is a desire to increase this voltage to 15 kilovolts to 20 kilovolts to increase the distance between repeaters.

[0003] The manufacturing, installation and use environments provide a varied set of extreme conditions to which the cable is exposed to. For example, cables are often exposed to hot and humid conditions during outdoor storage after manufacturing, also on ship decks during transport as well as extreme conditions under the sea. The coiling and uncoiling during transport and installation of the cables also imposes mechanical stresses. Given these environmental, handling and use conditions, a chief concern of cable manufacturers is the prevention of environmental stress cracking (“ESCR”). ESCR is the unexpected brittle failure of thermoplastic polymers caused by tensile stresses less than the polymer’s short-term mechanical strength. For example, World Intellectual Property Organization Publication number W02002086916A2 (“the ‘916 publication”) utilizes a multimodal resin to address the ESCR concern as unimodal resins -are known to exhibit relatively lower ESCR as the polymer density is increased. The ‘916 publication explains that “the multimodal polyolefin preferably has the following ESCR properties: F10 > 1500 h, more preferably > 8000 h; FI > 700 h, more preferably > 3000 h” as measured according to ASTM D1693-15 measured in 10% Igepal.

[0004] Polymeric compositions functioning as an insulation and/or jacketing of the cable must have a dielectric breakdown strength able to handle the electric current used to power the repeaters. There is a desire to increase the voltage powering the repeaters up to 20 kilovolts to expand the spacing of repeaters, but often the dielectric breakdown strength of the polymeric composition is too low to accommodate such voltages. A dielectric breakdown strength of greater than 400 kV/mm as measured according to ASTM D149 would allow current power up to 20 kilovolts greatly increasing the spacing of repeaters. The ‘916 publication describes the filtering of the multimodal polyolefin through 40 micrometer (“um “) to 250 um filter openings to form a material free from particles with a dimension larger than 0.5 mm in a 1 kg of material sample. The ‘916 publication explains that the removal of particulates is important because a “high cleanliness contributes to good electric properties of the combined insulation/jacket such that it can withstand a high operating stress in terms of electric field before electrical breakdown occurs.”

[0005] With the increased production of cables to improve data connectivity around the world, the cables and their subassemblies are spending longer periods of time exposed to ultraviolet radiation from the sun as they are stored in manufacturing yards next to production facilities. Conventional polymeric compositions used for insulation on cable conductors include no additives to abate ultraviolet exposure because, as highlighted above, even minor contaminants may drastically reduce the dielectric breakdown strength. Accordingly, conventional polymeric compositions used in cable insulation applications are unable to retain greater than 50% of the tensile elongation after 1500 hours of accelerated ultraviolet (“UV”) aging according to ASTM G151 which is typically required to mitigate outdoor exposure conditions. The decreased tensile elongation properties of conventional cable resins after exposure to UV light increase the risk of damage to the cable during outdoor storage, installation and use.

[0006] In view of the foregoing competing interests, it would be surprising to discover a unimodal polymeric composition that achieves an ESCR (F0) greater than 1,000 hours measured in 10% Igepal according to ASTM D1693-15, a dielectric breakdown strength of greater than 400 kV/mm as measured according to ASTM D149 and retains greater than 50% of the tensile elongation after 1500 hours of accelerated UV aging according to ASTM G151.

SUMMARY OF THE DISCLOSURE

[0007] The present disclosure provides a unimodal polymeric composition that can composition that achieves an ESCR (F0) greater than 1,000 hours measured in 10% Igepal according to ASTM D 1693- 15, a dielectric breakdown strength of greater than 400 kV/mm as measured according to ASTM D149 and retains greater than 50% of the tensile elongation after 1500 hours of accelerated UV aging according to ASTM G151 while still being suitable for the use of insulation and jacketing used in cables.

[0008] The inventors have discovered that despite contamination introduced to the polymeric composition by addition of ultraviolet light stabilizers, the dielectric breakdown strength of the polymeric composition can be maintained at a sufficient level while also providing sufficient tensile elongation retention after UV aging. Further, the inventors have recognized that incorporation of a unimodal resin is beneficial to the balancing of the properties. For example, unimodal resins typically contain less contaminants than bimodal resins, but also typically exhibit relatively decreased ESCR properties. By trading off the addition of the ultraviolet stabilizer with the use of the unimodal resin, the dielectric breakdown strength of the polymeric composition is preserved. Further, by utilizing a unimodal resin having a density of 0.93 g/cc to 0.94 g/cc, the ESCR value can be kept above the minimum desired value thereby mitigating the risk of damage to the cable. Accordingly, a polymeric composition that exhibits balanced properties and is still suitable for submarine fiber optic cables is provided.

[0009] According to a first feature of the present disclosure, a polymeric composition comprises an ethylene-based polymer having one and only one peak in a range from log(MW) 2.5 to log(MW) 7.0 in a plot of dW/dLog(MW) on the y-axis versus Log(MW) on the x-axis to give a Gel Permeation Chromatograph (GPC) chromatogram, wherein Log(MW) and dW/dLog(MW) are as defined herein and are measured by Gel Permeation Chromatograph (GPC) Test Method of the description, wherein the ethylene-based polymer has a density of 0.93 g/cc to 0.94 g/cc as measured according to ASTM D792; and an ultraviolet light stabilizer, wherein the polymeric composition is free of contaminants having an average particle size of 0.70 millimeters or greater as measured according to Contaminant Measurement Testing.

[0010] According to a second feature of the present disclosure, the polymeric composition comprises from 0.1 wt% to 0.7 wt% of the ultraviolet light stabilizer based on a total weight of the polymeric composition.

[0011] According to a third feature of the present disclosure, the ethylene-based polymer exhibits a melt index (E) of 0.1 g/lOmin to 1 g/lOmin as measured according to ASTM D1238. [0012] According to a fourth feature of the present disclosure, the ethylene-based polymer is a copolymer of ethylene and 1-hexene.

[0013] According to a fifth feature of the present disclosure, the polymeric composition exhibits: (i) a direct current (DC) electrical breakdown strength greater than 400 kilovolts per millimeter (kV/mm) as measured according to ASTM D149; (ii) a DC electrical endurance of greater than 1 ,000 seconds measured at 300 kV/mm according to ASTM DI 49; and (iii) a DC electrical endurance of greater than 300 seconds measured at 400 kV/mm according to ASTM D149.

[0014] According to a sixth feature of the present disclosure, the polymeric composition exhibits an environmental stress cracking resistance (ESCR, F0) greater than 1,000 hours, measured in 10% Igepal according to ASTM D1693-15.

[0015] According to a seventh feature of the present disclosure, the polymeric composition exhibits an elongation at break (initial) greater than 600%, as measured according to ASTM D638 and an aging elongation retention of greater than 40% after 1 ,500 hours exposure to ultraviolet (UV) light aging conditions according to ASTM G151.

[0016] According to an eighth feature of the present disclosure, the polymeric composition has less than 100 contaminants/kg in the range of 0.1778 mm to 0.406 mm as measured according to Contaminant Measurement Testing.

[0017] According to a ninth feature of the present disclosure, the polymeric composition has less than 5 contaminants/kg in the range of 0.178 mm to 0.406 mm and less than 5 contaminants/kg in the range of 0.406 mm to 0.699 mm as measured according to Contaminant Measurement Testing. [0018] According to a tenth feature of the present disclosure, a coated conductor comprises a conductor; and the polymeric composition of any one of features 1-9 disposed around the conductor.

BRIEF DESCRIPTION OF THE DRAWING

[0019] Reference is made to the accompanying drawings in which: [0020] FIG. 1 shows a graph of direct current ageing performance.

DETAILED DESCRIPTION

[0021] As used herein, the term “and/or,” when used in a list of two or more items, means that any one of the listed items can be employed by itself, or any combination of two or more of the listed items can be employed. For example, if a composition is described as containing components A, B, and/or C, the composition can contain A alone; B alone; C alone; A and B in combination; A and C in combination; B and C in combination; or A, B, and C in combination.

[0022] All ranges include endpoints unless otherwise stated.

[0023] Test methods refer to the most recent test method as of the priority date of this document unless a date is indicated with the test method number as a hyphenated two-digit number. References to test methods contain both a reference to the testing society and the test method number. Test method organizations are referenced by one of the following abbreviations: ASTM refers to ASTM International (formerly known as American Society for Testing and Materials); IEC refers to International Electrotechnical Commission; EN refers to European Norm; DIN refers to Deutsches Institut fur Normung; and ISO refers to International Organization for Standards.

[0024] As used herein, the term weight percent (“wt%”) designates the percentage by weight a component is of a total weight of the polymeric composition unless otherwise specified.

[0025] Melt index (h) values herein refer to values determined according to ASTM method DI 238 at 190 degrees Celsius (°C) with 2.16 Kilogram (Kg) mass and are provided in units of grams eluted per ten minutes (“g/10 min”).

[0026] Density values herein refer to values determined according to ASTM D792 at 23 °C and are provided in units of grams per cubic centimeter (“g/cc”).

[0027] As used herein, Chemical Abstract Services registration numbers (“CAS#”) refer to the unique numeric identifier as most recently assigned as of the priority date of this document to a chemical compound by the Chemical Abstracts Service.

Polymeric Composition

[0028] The present invention comprises an ethylene polymer and an ultraviolet light stabilizer. The polymeric composition is free of contaminants having particle size of 0.70 millimeters (“mm”) or greater as measured according to Contaminant Measurement Testing as described in greater detail below. As used herein, the term “free of’ is defined to mean that the polymeric composition has no detected material, according to the appropriate testing method, that the polymeric composition is free of. As provided herein, the term “contaminant” means a discrete particle disposed within the continuous polymeric composition phase that is not intentionally added. Examples of contaminants include dust, hair, grease, grease, degraded material, antioxidant agglomerations, metal pieces, fibers, etc. The polymeric composition has less than 100 contaminants/kg in the range of 0.1778 mm to 0.406 mm as measured according to Contaminant Measurement Testing. For example, the polymeric composition has 100 contaminants/kg or less, or 90 contaminants/kg or less, or 80 contaminants/kg or less, or 70 contaminants/kg or less, or 60 contaminants/kg or less, or 50 contaminants/kg or less, or 40 contaminants/kg or less, or 30 contaminants/kg or less, or 20 contaminants/kg or less, or 10 contaminants/kg or less, or 5 contaminants/kg or less, or 1 contaminant/kg or less in the range of 0.1778 mm to 0.406 as measured according to Contaminant Measurement Testing.

[0029] The polymeric composition comprises 100 contaminants/kg or less in the range of 0.406 mm to 0.699 mm. For example, the polymeric composition has 100 contaminants/kg or less, or 90 contaminants/kg or less, or 80 contaminants/kg or less, or 70 contaminants/kg or less, or 60 contaminants/kg or less, or 50 contaminants/kg or less, or 40 contaminants/kg or less, or 30 contaminants/kg or less, or 20 contaminants/kg or less, or 10 contaminants/kg or less, or 5 contaminants/kg or less, or 1 contaminant/kg or less in the range of 0.406 mm to 0.699 mm as measured according to Contaminant Measurement Testing.

Ethylene-based Polymer

[0030] As noted above, the polymeric composition comprises the ethylene-based polymer. As used herein, “ethylene-based” polymers are polymers in which greater than 50 wt% of the monomers are ethylene though other co-monomers may also be employed. The ethylene-based polymer can include ethylene and one or more C3-C20 a-olefin comonomers such as propylene, 1-butene, 1 pentene, 4-methyl-l -pentene, 1-hexene, and 1-octene. The ethylene-based be used alone or in combination with one or more other types of ethylene-based polymers (e.g., a blend of two or more ethylene-based polymers that differ from one another by monomer composition and content, catalytic method of preparation, molecular weight, molecular weight distributions, densities, etc.). If a blend of ethylene-based polymers is employed, the polymers can be blended by any in-reactor or post-reactor process.

[0031] The ethylene-based polymer may comprise 50 wt% or greater, 60 wt% or greater, 70 wt% or greater, 80 wt% or greater, 85 wt% or greater, 90 wt% or greater, or 91 wt% or greater, or 92 wt% or greater, or 93 wt% or greater, or 94 wt% or greater, or 95 wt% or greater, or 96 wt% or greater, or 97 wt% or greater, or 97.5 wt% or greater, or 98 wt% or greater, or 99 wt% or greater, while at the same time, 99.5 wt% or less, or 99 wt% or less, or 98 wt% or less, or 97 wt% or less, or 96 wt% or less, or 95 wt% or less, or 94 wt% or less, or 93 wt% or less, or 92 wt% or less, or 91 wt% or less, or 90 wt% or less, or 85 wt% or less, or 80 wt% or less, or 70 wt% or less, or 60 wt% or less of ethylene as measured using Nuclear Magnetic Resonance (NMR) or Fourier- Transform Infrared (FTIR) Spectroscopy. Other units of the ethylene-based polymer may include C3, or C4, or Ce, or Cs, or C10, or C12, or Ci6, or Cis, or C20 a-olefins, such as propylene, 1-butene, 1 -hexene, 4-methyl-1 -pentene, and 1 -octene. Tn a specific example, the ethylene-based polymer is a copolymer of ethylene and 1 -hexene.

[0032] The polymeric composition may comprise from 80 wt% to 99.9 wt% of the ethylene-based polymer based on the total weight of the polymeric composition. For example, the polymeric composition comprises 80 wt% or greater, or 85 wt% or greater, or 90 wt% or greater, or 95 wt% or greater, or 99 wt% or greater, or 99.8 wt% or greater, while at the same time, 99.9 wt% or less, or 99.8 wt% or less, or 95 wt% or less, or 90 wt% or less, or 85 wt% or less of the ethylene-based polymer based on the total weight of the polymeric composition.

[0033] The ethylene-based polymer has a density of 0.930 g/cc or greater, or 0.931 g/cc or greater, or 0.932g/cc or greater, or 0.933 g/cc or greater, or 0.934 g/cc or greater, or 0.935 g/cc or greater, or 0.936 g/cc or greater, or 0.937 g/cc or greater, or 0.938 g/cc or greater, or 0.939 g/cc or greater, while at the same time, 0.940 g/cc or less, or 0.939 g/cc or less, or 0.938 g/cc or less, or 0.937 g/cc or less, or 0.936 g/cc or less, or 0.935 g/cc or less, or 0.934 g/cc or less, or 0.933 g/cc or less, or 0.932 g/cc or less, or 0.931 g/cc or less as measured by ASTM D792.

[0034] The ethylene-based polymer has a melt index (I2) of 0.1 g/lOmin to 1 g/lOmin as measured according to ASTM D1238. For example, the ethylene-based polymer may have a melt index (I2) of 0.1 g/lOmin or greater, or 0.2 g/lOmin or greater, or 0.3 g/lOmin or greater, or 0.4 g/lOmin or greater, or 0.5 g/lOmin or greater, or 0.6 g/lOmin or greater, or 0.7 g/lOmin or greater, or 0.8 g/lOmin or greater, or 0.9 g/lOmin or greater, while at the same time, 1.0 g/lOmin or less, or 0.9 g/lOmin or less, or 0.8 g/lOmin or less, or 0.7 g/lOmin or less, or 0.6 g/lOmin or less, or 0.5 g/lOmin or less, or 0.4 g/lOmin or less, or 0.3 g/lOmin or less, or 0.2 g/lOmin or less as measured according to ASTM D1238.

[0035] The ethylene-based polymer is a unimodal polymer as determined by the Unimodal Test Method provided below. As a unimodal polymer, the ethylene-based polymer has one and only one peak in a range from log(MW) 2.5 to log(MW) 7.0 in a plot of dW/dLog(MW) on the y-axis versus Log(MW) on the x-axis to give a Gel Permeation Chromatograph (GPC) chromatogram, wherein Log(MW) and dW/dLog(MW) are as defined herein and are measured by Gel Permeation Chromatograph (GPC) Test Method as provided in greater detail below. Ultraviolet Light Stabilizer

[0036] The ultraviolet light stabilizer included in the polymeric composition may include hindered amine light stabilizers (“HALS”) and/or UV light absorber (“UVA”) additives. Representative UVA additives include triazine based UVAs, oligomeric UVAs, polymeric UVAs, benzophenonebased UVAs, salicylate-based UVAs and/or acrylonitrile-based UVAs. UVAs are available under the commercial tradenames TINUVIN™ 234, TINUVIN™ 326, TINUVTN™ 328, TINUVIN™ 329, TINUVIN™ 400, TINUVIN™ 405, TINUVIN™ 460, TINUVIN™ 479, TINUVIN™ 900, TINUVIN™ 928, and TINUVIN™ 1130, all manufactured by BASF, Ludwigshafen, Germany. Additional commercial examples include UVASORB™ HA88 from 3V Sigma USA, Georgetown, South Carolina, USA and CYASORB™ THT 4801, THT 7001, and THT 6460 (each commercially available from Solvay Corp., Brussels, Belgium.).

[0037] The polymeric composition may comprise one or more HALS. The HALS may include one or more of poly(4-hydroxy-2,2,6,6-tetramethyl-l-piperidineethanol-alt-l ,4-butanedioic acid) (CAS# 65447-77-0); bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate (CAS# 52829-07-9); di- (l,2,2,6,6-pentamethyl-4-piperidyl)-2-butyl-2-(3,5-di-tert-b utyl-4-hydroxybenzyl)malonate (CAS# 63843-89-0); bis(l-octyloxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate (CAS# 129757-67- 1); poly[[6-[(l,l,3,3-tetramethylbutyl)amino]-s-triazine-2,4-diy l]-[(2,2,6,6-tetramethyl-4- piperidyl)imino]-hexamethylene-[(2,2,6,6-tetramethyl-4-piper idyl)imino] (CAS# 71878-19-8); l,3,5-Triazine-2,4,6-triamine, N,N"'-l,2-ethanediylbis[N-[3-[[4,6-bis[butyl(l,2,2,6,6- pentamethyl-4-piperidinyl)amino]-l,3,5-triazin-2-yl]amino]pr opyl]-N',N"-dibutyl-N',N"- bis(l,2,2,6,6-pentamethyl-4-piperidinyl)- (CAS# 106990-43-6); 1,6-Hexanediamine, N,N'- bis(2,2,6,6-tetramethyl-4-piperidinyl)-, polymer with 2,4,6-trichloro-l,3,5-triazine, reaction products with, N-butyl-l-butanamine and N-butyl-2,2,6,6-tetramethyl-4-piperidinamine (CAS# 192268-64-7). Examples of the HALS are commercially available under the tradenames TINUVIN™ 622 and CHIMASSORB™ 944 from BASF, Ludwigshafen, Germany.

[0038] The polymeric composition may comprise from 0.1 wt% to 1.0 wt% of the ultraviolet light stabilizer based on the total weight of the polymeric composition. For example, the polymeric composition may comprise 0.1 wt% or greater, or 0.2 wt% or greater, or 0.3 wt% or greater, or 0.4 wt% or greater, or 0.5 wt% or greater, or 0.6 wt% or greater, or 0.7 wt% or greater, or 0.8 wt% or greater, or 0.9 wt% or greater, while at the same time, 1.0 wt% or less, or 0.9 wt% or less, or 0.8 wt% or less, or 0.7 wt% or less, or 0.6 wt% or less, or 0.5 wt% or less, or 0.4 wt% or less, or 0.3 wt% or less, or 0.2 wt% or less of the ultraviolet light stabilizer based on the total weight of the polymeric composition. Mechanical Properties

[0039] The polymeric composition may exhibit a non-UV aged or UV aged maximum tensile strength of 20.0 megapascals (MPa) to 35.0 MPa as measured according to ASTM D638. For example the polymeric composition may exhibit a maximum tensile strength of 20.0 MPa or greater, or 20.5 MPa or greater, or 21.0 MPa or greater, or 21.5 MPa or greater, or 22.0 MPa or greater, or 22.5 MPa or greater, or 23.0 MPa or greater, or 23.5 MPa or greater, or 24.0 MPa or greater, or 24.5 MPa or greater, or 25.0 MPa or greater, or 25.5 MPa or greater, or 26.0 MPa or greater, or 26.5 MPa or greater, or 27.0 MPa or greater, or 27.5 MPa or greater, or 28.0 MPa or greater, or 28.5 MPa or greater, or 29.0 MPa or greater, or 29.5 MPa or greater, or 30.0 MPa or greater, or 30.5 MPa or greater, or 31.0 MPa or greater, or 31.5 MPa or greater, or 32.0 MPa or greater, or 32.5 MPa or greater, or 33.0 MPa or greater, or 33.5 MPa or greater, or 34.0 MPa or greater, or 34.5 MPa or greater, while at the same time, 35.0 MPa or less, or 34.5 MPa or less, or 34.0 MPa or less, or 33.5 MPa or less, or 33.0 MPa or less, or 32.5 MPa or less, or 32.0 MPa or less, or 31.5 MPa or less, or 31.0 MPa or less, or 30.5 MPa or less, or 30.0 MPa or less, or 29.5 MPa or less, or 29.0 MPa or less, or 28.5 MPa or less, or 28.0 MPa or less, or 27.5 MPa or less, or 27.0 MPa or less, or 26.5 MPa or less, or 26.0 MPa or less, or 25.5 MPa or less, or 25.0 MPa or less, or 24.5 MPa or less, or 24.0 MPa or less, or 23.5 MPa or less, or 23.0 MPa or less, or 22.5 MPa or less, or 22.0 MPa or less, or 21.5 MPa or less, or 21.0 MPa or less, or 20.5 MPa or less.

[0040] The polymeric composition may exhibit a non-UV aged elongation at break or UV aged elongation at break of 600% to 1000% as measured according to ASTM D638. For example the polymeric composition may exhibit an elongation at break of 600% or greater, or 610% or greater, or 620% or greater, or 630% or greater, or 640% or greater, or 650% or greater, or 660% or greater, or 670% or greater, or 680% or greater, or 690% or greater, or 700% or greater, or 710% or greater, or 720% or greater, or 730% or greater, or 740% or greater, or 750% or greater, or 760% or greater, or 770% or greater, or 780% or greater, or 790% or greater, or 800% or greater, or 810% or greater, or 820% or greater, or 830% or greater, or 840% or greater, or 850% or greater, or 860% or greater, or 870% or greater, or 880% or greater, or 890% or greater, or 900% or greater, or 910% or greater, or 920% or greater, or 930% or greater, or 940% or greater, or 950% or greater, or 960% or greater, or 970% or greater, or 980% or greater, or 990% or greater, while at the same time, 1000% or less, or 990% or less, or 980% or less, or 970% or less, or 960% or less, or 950% or less, or 940% or less, or 930% or less, or 920% or less, or 910% or less, or 900% or less, or 890% or less, or 880% or less, or 870% or less, or 860% or less, or 850% or less, or 840% or less, or 830% or less, or 820% or less, or 810% or less, or 800% or less, or 790% or less, or 780% or less, or 770% or less, or 760% or less, or 750% or less, or 740% or less, or 730% or less, or 720% or less, or 710% or less, or 700% or less, or 690% or less, or 680% or less, or 670% or less, or 660% or less, or 650% or less, or 640% or less, or 630% or less, or 620% or less, or 610% or less as measured according to ASTM D638.

[0041] The polymeric composition may have a retained maximum tensile strength and/or a retained elongation at break (both measured by dividing the UV aged value by the non-UV aged value) of 40% or greater, or 45% or greater, or 50% or greater, 55% or greater, or 60% or greater, or 65% or greater, or 70% or greater, or 75% or greater, or 80% or greater, or 85% or greater, or 90% or greater, or 95% or greater, while at the same time, 100% or less, or 95% or less, or 90% or less, or 85% or less, or 80% or less, or 75% or less, or 70% or less, or 65% or less, or 60% or less, or 55% or less, or 50% or less, or 45% or less.

[0042] The polymeric composition may exhibit an ESCR (F0) of greater than 1000 hours as measured in 10% Igepal according to ASTM D1693-15. For example, the polymeric composition may exhibit an ESCR (F0) of 1000 hours or greater, or 1100 hours or greater, or 1200 hours or greater, or 1300 hours or greater, or 1400 hours or greater, or 1500 hours or greater, or 1600 hours or greater, or 1700 hours or greater, or 1800 hours or greater, or 1900 hours or greater, while at the same time, 2000 hours or less, or 1900 hours or less, or 1800 hours or less, or 1700 hours or less, or 1600 hours or less, or 1500 hours or less, or 1400 hours or less, or 1300 hours or less, or 1200 hours or less, or 1100 hours or less, as measured in 10% Igepal according to ASTM D1693- 15.

Electrical Properties

[0043] The polymeric composition may exhibit a direct current (DC) electrical breakdown strength greater than 400 kilovolts per millimeter (kV/mm) as measured according to ASTM D149. For example, the polymeric composition may exhibit a DC electrical breakdown strength of 401 kV/mm or greater, or 410 kV/mm or greater, or 420 kV/mm or greater, or 430 kV/mm or greater, or 440 kV/mm or greater, or 450 kV/mm or greater, or 460 kV/mm or greater, or 470 kV/mm or greater, or 480 kV/mm or greater, or 490 kV/mm or greater, while at the same time, 500 kV/mm or less, or 490 kV/mm or less, or 480 kV/mm or less, or 470 kV/mm or less, or 460 kV/mm or less, or 450 kV/mm or less, or 440 kV/mm or less, or 430 kV/mm or less, or 420 kV/mm or less, or 410 kV/mm or less as measured according to ASTM D149.

[0044] The polymeric composition may exhibit a DC electrical endurance of greater than 1,000 seconds measured at 300 kV/mm according to ASTM D149. For example, the polymeric composition may exhibit a DC electrical endurance of 1,001 seconds or greater, or 1500 seconds of greater, or 2000 seconds or greater, or 2500 seconds or greater, or 3000 seconds or greater, or 3500 seconds or greater, or 4000 seconds or greater, or 4500 seconds or greater, or 5000 seconds or greater, or 5500 seconds or greater, or 6000 seconds or greater, or 6500 seconds or greater, or 7000 seconds or greater, or 7500 seconds or greater, or 8000 seconds or greater, or 8500 seconds or greater, or 9000 seconds or greater, or 9500 seconds or greater as measured at 300 kV/mm according to ASTM DI 49.

[0045] The polymeric composition may exhibit a DC electrical endurance of greater than 300 seconds measured at 400 kV/mm according to ASTM D149. For example, the polymeric composition may exhibit a DC electrical endurance of 301 seconds or greater, or 350 seconds of greater, or 450 seconds or greater, or 500 seconds or greater, or 550 seconds or greater, or 600 seconds or greater, or 650 seconds or greater, or 700 seconds or greater, or 750 seconds or greater, or 800 seconds or greater, or 850 seconds or greater, or 900 seconds or greater, or 950 seconds or greater as measured at 400 kV/mm according to ASTM D149.

Coated Conductor

[0046] The present disclosure also provides a coated conductor. The coated conductor includes a conductor and a coating on the conductor, the coating including the polymeric composition. The polymeric composition is at least partially disposed around the conductor to produce the coated conductor. The conductor may comprise a conductive metal.

[0047] The process for producing a coated conductor includes mixing and heating the polymeric composition to at least the melting temperature of the polymeric components in an extmder to form a polymeric melt blend, and then coating the polymeric melt blend onto the conductor. The term "onto" includes direct contact or indirect contact between the polymeric melt blend and the conductor. The polymeric melt blend is in an extrudable state.

[0048] The polymeric composition is disposed around on and/or around the conductor to form a coating. The coating may be one or more inner layers such as an insulating layer. The coating may wholly or partially cover or otherwise surround or encase the conductor. The coating may be the sole component surrounding the conductor. Alternatively, the coating may be one layer of a multilayer jacket or sheath encasing the conductor. The coating may directly contact the conductor. The coating may directly contact an insulation layer surrounding the conductor. Examples

Materials

[0049] The following materials are employed in the Examples, below.

[0050] Resin is an ethylene-based polymer that is unimodal as measured according to the Unimodal Test Method provided below. The Resin is comprised of an ethylene/ 1 -hexene copolymer and has a density of 0.935 g/cc and a melt index of 0.70 g/10 min, which is available from The Dow Chemical Company, Midland, MI, USA.

[0051] Stabilizer a hindered amine light stabilizer (CAS# 70624-18-9) having the chemical name poly [[6-[(l, 1,3, 3-tetramethylbutyl)amino]-l, 3, 5-triazine-2,4-diyl] [(2,2,6, 6-tetramethyl-4- piperidinyl)imino]-l,6 hexanediyl[(2,2,6,6-tetramethyl-4- piperidinyl)imino]]), and is commercially available as CHIMASSORB™ 944 from BASF, Ludwigshafen, Germany.

[0052] Comparative is a UV stabilized resin sold commercially as K-3364 from Eneos NUC Group, Kawasaki Kanagawa, Japan.

Sample Preparation

[0053] Samples were prepared by mixing the pelleted polymer resin and the Stabilizer in a FARREL™ Banbury internal mixer at 155°C. The rotor speed of the mixer was set to 30 revolutions per minute (“RPM”). The mixture was then dropped at 155°C into a melt-fed, singlescrew extruder. The extruder was a FARREL™ 4.5 inch screw with a 14: 1 length to diameter ratio. The melt was then passed through a KREYENBOURG™ dual-bolt, continuous screen changer (with screen pack of 20-400-200-100-20 mesh) and pelletized utilizing a GALA™ underwater pelletizer.

[0054] To form plaques for mechanical and electrical testing, the materials from the pelletizer were compression molded using a WABASH™ Genesis Steam Press (with quench cooling capability) operated in manual mode. 20.3 centimeter by 20.3 centimeter plaques with thickness of either 0.0254 cm or 0.19 cm were prepared for each sample and cut into proper sizes for testing. The press was preheated to 160°C. The pellets were placed between the mold assembly made up of polyethylene terephthalate film and aluminum sheets. The filled mold was then placed into the press at 0.35 MPa for 5 minutes to pre-heat and melt the compounds. The press was switched to high pressure mode and pressure was increased to 19.3 MPa for another 3 minutes for forming the plaques. Afterwards, the sample was quench-cooled to 40°C at 19.3 MPa before the plaque sample was taken out.

[0055] To form tape extrusions for Contaminant Testing, a BRABENDER™ extruder was used to make tapes with thickness of 0.1 cm and a width of 10.2 cm. The extrusion temperature profile of the extruder was set at 140/150/160/170°C (the die), and screw speed was 30 revolutions per minute. Prior to loading the pellets, the hopper, screw, die, and other parts of the extruder that contact the polymeric composition were well cleaned. At the beginning of the run, the extruder was purged for 30 minutes to remove any possible contaminations in the extruder. One kilogram of each sample was collected and evaluated for cleanliness.

Test Methods

[0056] Contaminant Measurement Testing: The prepared tape samples were placed on a lighted viewing table and were wiped with cheesecloth before examination to remove surface contamination. The tapes were examined using an illuminated magnifying glass. The size of contaminants detected were determined by the longest length dimension of the contaminant.

[0057] Tensile strength maximum and tensile elongation at break of the samples was performed in accordance with ASTM D638 on a 5565 tensile testing machine from Instron Calibration Lab. [0058] The DC dielectric breakdown strength and DC aging test were performed using a PSD- 10010DC6 tester from by High Voltage Inc in accordance with ASTM D149. The 0.0254 cm thick plaques were used for DC dielectric breakdown strength and DC aging tests.

[0059] Ultraviolet aging testing was performed according to ASTM G151 using the following exposure conditions: 20 hours of exposure to UVA-340 fluorescent lamps with uninsulated black panel temperature maintained at the control point at 70 ± 3°C followed by 4 hour darkness with condensation at an uninsulated black panel temperature maintained at the control point at 55 ± 3°C. Irradiance at the control point was maintained at 0.70 + 0.02 W/(m.nm) at 340 nm when using the irradiance controlled apparatus. The 0.19 cm thick samples were used for ultraviolet aging testing.

[0060] Gel permeation chromatography (GPC) Method: Weight- Average Molecular Weight Test Method: determine weight average molecular weight (M _w ), number average molecular weight (M _n ), and M _w /M _n using chromatograms obtained on a High Temperature Gel Permeation Chromatography instrument (HTGPC, Polymer Laboratories). The HTGPC is equipped with transfer lines, a differential refractive index detector (DRI), and three Polymer Laboratories PLgel 10pm Mixed-B columns, all contained in an oven maintained at 160° C. Method uses a solvent composed of BHT-treated TCB at nominal flow rate of 1.0 milliliter per minute (mL/min.) and a nominal injection volume of 300 microliters (pL). Prepare the solvent by dissolving 6 grams of butylated hydroxytoluene (BHT, antioxidant) in 4 liters (L) of reagent grade 1,2,4- trichlorobenzene (TCB), and filtering the resulting solution through a 0.1 micrometer (pm) Teflon filter to give the solvent. Degas the solvent with an inline degasser before it enters the HTGPC instrument. Calibrate the columns with a series of monodispersed polystyrene (PS) standards. Separately, prepare known concentrations of test polymer dissolved in solvent by heating known amounts thereof in known volumes of solvent at 160° C. with continuous shaking for 2 hours to give solutions. (Measure all quantities gravimetric ally.) Target solution concentrations, c, of test polymer of from 0.5 to 2.0 milligrams polymer per milliliter solution (mg/mL), with lower concentrations, c, being used for higher molecular weight polymers. Prior to running each sample, purge the DRI detector. Then increase flow rate in the apparatus to 1.0 mL/min/, and allow the DRI detector to stabilize for 8 hours before injecting the first sample. Calculate M _w and M _n using universal calibration relationships with the column calibrations. Calculate MW at each elution volume with following equation:

, , log A

•> where subscript “X” stands for the test sample, subscript “PS” stands for PS standards, a _PS =0.67 , K _ps =0.000175, and a _x and K _x are obtained from published literature. For polyethylenes, a _x /K _x = 0.695/0.000579. For polypropylenes a _x K _x = 0.705/0.0002288. At each point in the resulting chromatogram, calculate concentration, c, from a baseline-subtracted DRI signal, I D R | , using the following equation: c = Kp)R[Ip)R[/(dn/dc). wherein X^/ is a constant determined by calibrating the DRI, / indicates division, and dn/dc is the refractive index increment for the polymer. For polyethylene, dn/dc = 0.109. Calculate mass recovery of polymer from the ratio of the integrated area of the chromatogram of concentration chromatography over elution volume and the injection mass which is equal to the pre-determined concentration multiplied by injection loop volume. Report all molecular weights in grams per mole (g/mol) unless otherwise noted. Further details regarding methods of determining Mw, Mn, MWD are described in US 2006/0173123 page 24-25, paragraphs [0334] to [0341], Plot of dW/dLog(MW) on the y-axis versus Log(MW) on the x-axis to give a GPC chromatogram, wherein Log(MW) and dW/dLog(MW) are as defined above.

[0061] Unimodal Test Method: presence or absence of unimodality was determined by plotting dWf/dLogM (mass detector response) on y-axis versus LogM on the x-axis to obtain a GPC chromatogram curve containing local maxima log(MW) values for LMW and HMW polyethylene component peaks, and observing the presence or absence of a local minimum between the LMW and HMW polyethylene component peaks. The dWf is change in weight fraction, dLogM is also referred to as dLog(MW) and is change in logarithm of molecular weight, and LogM is also referred to as Log(MW) and is logarithm of molecular weight.

[0062] ESCR (F0) was measured according to ASTM DI 693- 15 in 10% Tgepal.

Results

[0063] Table 1 provides the composition and tested properties of comparative examples 1 and 2 (“CE1” and “CE2”) as well as those for inventive examples 1 and 2 (“IE1” and “IE2”).

Table 1

Referring now to Table 1 and FIG. 1, it can be seen that CE1, which has the same base resin as IE1 and IE2 does not meet all of the established criteria. For example, despite passing the desired ESCR and DC breakdown strength values, it is clear that ultraviolet aging of CE1 has left an unacceptably low tensile elongation retention. Such a low tensile elongation retention could result in cracks and other damage occurring to a cable using this composition after sun exposure. CE2 similarly fails to meet all of the desired properties including the lack of tensile elongation retention. Unlike the comparative examples, IE1 and IE2 are each able to achieve an ESCR greater than 1 ,000 hours measured in 10% Tgepal according to ASTM D1693-15, a dielectric breakdown strength of greater than 400 kV/mm as measured according to ASTM D149 and retains greater than 50% of the tensile elongation after 1500 hours of accelerated UV aging according to ASTM G151 as desired. Such a result is surprising in that despite the addition of the ultraviolet light stabilizer, the DC breakdown strength remains sufficiently high. Additionally, the addition of the ultraviolet light stabilizer provides sufficient protection to the polymeric composition to retain 40% or greater of the tensile elongation at break thereby reducing the risk of damage after prolonged sun exposure. Further, from the trend lines provided in FIG. 1, it can be seen that IE1 would be expected to exhibit a DC electrical endurance of greater than 1 ,000 seconds measured at 300 kV/mm according to ASTM D149 while CE1 would not be expected to meet this value.