Filled wet-crosslinkable polymer composition

Abstract

A polymer composition comprising an ethylene-silane copolymer comprising units derived from an ethylene monomer and a silane monomer wherein the ethylene-silane copolymer has a cosilane content of from 0.40 mol% to 1.00 mol% based on a total molar amount of the ethylene-silane copolymer; a Lewis acid catalyst; and a halogen-free flame retardant selected from the group consisting of a metal hydrate, silica, and combinations thereof.

Description

Background Art Technical Field

[0001] The present disclosure relates to polymer compositions, and more particularly to filled moisture-crosslinkable polymer compositions.

[0002] introduction

[0003] Ethylene-silane copolymers are used to form wet crosslinkable polymer compositions. Such polymer compositions are used to manufacture wires and cables (i.e., coated conductors), including low-voltage cable constructions, and can be used as sheaths or electrical insulation materials in cable constructions. Silane comonomers copolymerized with ethylene to prepare ethylene-silane copolymers promote crosslinking of the polymer composition. Crosslinking of the polymer composition is achieved by "curing" the coated conductor under wet conditions. The copolysilane content of the copolymer can be adjusted according to the desired cure level of the polymer composition. For example, U.S. Patent No. 8,460,770 ("the '770 patent") discloses that ethylene-silane copolymers can contain 0.5 wt % to 5 wt % of silane comonomers.

[0004] In addition to the final level of crosslinking experienced by the polymer composition, the silane content of the copolymer (with a given silane) also affects the cure rate. While higher co-silane levels advantageously accelerate the cure rate of the polymer composition, resulting in an increased degree of final cure (crosslinking) and improved mechanical properties, such as peak tensile stress, other mechanical properties, such as tensile strain at break, are affected as the co-silane content increases. The use of ethylene-silane copolymers having a silane content of 0.4 mol% or more results in tensile strain at break values ​​that are lower than those obtained using comparable ethylene-silane copolymers having a silane content of less than 0.4 mol%. In the case of coated conductors, a tensile strain at break of 20% or greater is measured at a displacement rate of 20 inches per minute in accordance with Underwriter's Laboratory ("UL") 2556, Section 3.5. Tensile properties of extruded tapes or compression molded samples can also be measured in accordance with ASTM D638-14 at a displacement rate of 20 inches per minute (using Type IV dog-bone specimens obtained from the tapes or compression molded samples).

[0005] It is also known that the inclusion of fillers in polymers has a deleterious effect on the tensile strain at break (also known as tensile elongation) of polymer compositions. FIG4 of the Journal of Saudi Chemical Society, Vol. 19, No. 1, January 2015, pp. 88-91, illustrates this phenomenon using polyethylene and various fillers, including calcium carbonate. In the case of wire and cable, representative fillers used to prepare polymer compositions include calcium carbonate, carbon black, halogenated flame retardants, and flame retardant synergists (e.g., antimony trioxide), all of which typically reduce the tensile strain at break of polymer compositions. The inhibitory effect of fillers on the tensile strain at break of cable insulation or jacketing can be controlled by preparing moisture-crosslinkable polymer compositions using ethylene-silane copolymers with a low copolysilane content (typically less than 0.4 mol% silane), but the benefits of faster cure rates and increased cure levels are lost due to the reduced silane content.

[0006] As described above, for a given silane, the silane content of the ethylene-silane copolymer affects the rate and level of cure experienced by the polymer composition. A common measure of the final crosslinking level of a silane-functionalized polymer is to measure the percentage of thermal creep achieved after the polymer composition has been cured in a 90°C water bath for at least 4 hours and up to 72 hours ("final cure") . This can be done before or after conditioning at 23°C and 50% relative humidity for several hours, days, or weeks (from 0 hours to up to 12 weeks). Thermal creep is measured by the aforementioned test method at a specific temperature (200°C or 150°C) under a fixed stress (e.g., 0.2 MPa), based on Section 7.9 of Underwriters Laboratories ("UL") 2556 or the Insulation Cable Engineers Association (ICEA) standard ICEA-T-28-562-2003 for power cable insulation. Ideally, the polymer composition achieves a hot creep after final cure of 175% or less as measured according to UL 2556 Section 7.9 or ICEA-T-28-562-2003.

[0007] In view of the foregoing, it would be surprising to discover a filled, moisture-crosslinkable polymer composition that does not suffer a loss in tensile strain at break (or even exhibits an increased tensile strain at break) compared to polymer compositions using ethylene-silane copolymers having less than 0.4 mol % of copolysilane, and that achieves a hot creep after final cure of 175% or less as measured in accordance with UL 2556, Section 7.9 or ICEA-T-28-562-2003. Summary of the Invention

[0008] The inventors of the present disclosure have surprisingly discovered a filled, moisture-crosslinkable polymer composition that does not suffer a loss in tensile strain at break (or even exhibits an increased tensile strain at break) compared to polymer compositions using ethylene-silane copolymers having less than 0.4 mol % of copolysilane, and that achieves a hot creep after final cure of 175% or less as measured according to UL 2556 Section 7.9 or ICEA-T-28-562-2003.

[0009] The present invention is the result of the discovery that, unlike other filler materials, incorporating a halogen-free, flame-retardant filler comprising a metal hydrate into an ethylene-silane copolymer having a copolysilane content of 0.40 to 1.00 mol% surprisingly enhances the tensile strain at break of a polymer composition. This result is surprising, as other filler types have a suppressive effect on the observed mechanical properties. Without being bound by theory, it is believed that the hydroxide moiety of the metal hydrate filler facilitates compatibilization of the ethylene-silane copolymer with the flame-retardant filler, thereby enhancing the mechanical properties of the polymer composition. In addition to fillers having hydroxide moieties, those with hydroxyl groups on their surfaces, such as silica, are also within the scope of the present invention. Such characteristics are advantageous for providing flame retardancy to polymer compositions while achieving the desired tensile strain at break. Furthermore, the surprising effect of the metal hydrate filler on the mechanical properties of the polymer composition means that ethylene-silane copolymers having a copolysilane content of 0.40 to 1.00 mol% can be used, allowing cables to reach target hot creep values ​​more quickly and achieve a greater final strength. Additionally, relatively larger amounts of non-silane functionalized polymers, such as linear polyethylene, can be incorporated into the formulation to enhance properties, if desired, while still maintaining the desired degree of cross-linking.

[0010] The invention is particularly useful in the manufacture of wire and cable.

[0011] According to a first feature of the present disclosure, a polymer composition includes an ethylene-silane copolymer comprising units derived from an ethylene monomer and a silane monomer, wherein the ethylene-silane copolymer has a copolymerized silane content of 0.40 mol% to 1.00 mol%, based on the total molar amount of the ethylene-silane copolymer; a Lewis acid catalyst; and a halogen-free flame retardant selected from the group consisting of metal hydrates, silica, and combinations thereof.

[0012] According to a second feature of the present disclosure, the Lewis acid catalyst is selected from the group consisting of dibutyltin dilaurate, dioctyltin dilaurate, aluminum chloride, titanium chloride, zinc chloride, dimethylhydroxytin oleate, dioctyltin maleate, di-n-butyltin maleate, dibutyltin diacetate, dibutyltin dioctoate, stannous acetate, stannous octoate, lead naphthenate, zinc octoate and cobalt naphthenate, and combinations thereof.

[0013] According to the third feature of the present disclosure, the metal hydrate is selected from the group consisting of aluminum hydroxide, magnesium hydroxide, brucite, calcium hydroxide, zinc hydroxide, iron hydroxide, copper hydroxide, and combinations thereof.

[0014] According to a fourth feature of the present disclosure, the polymer composition includes 10 to 80 wt % of a halogen-free flame retardant based on the total weight of the polymer composition.

[0015] According to a fifth feature of the present disclosure, the polymer composition includes 10 to 90 wt% of the ethylene-silane copolymer, based on the total weight of the polymer composition.

[0016] According to a sixth feature of the present disclosure, the polymer composition exhibits a filler to catalyst weight ratio of 75 to 1000.

[0017] According to a seventh feature of the present disclosure, the ethylene-silane copolymer exhibits a crystallinity at 23° C. of 40 to 46 weight % as measured according to a Crystallinity Test.

[0018] According to an eighth feature of the present disclosure, the ethylene-silane copolymer has a copolymerized silane content of 0.45 mol % to 0.85 mol %.

[0019] According to a ninth feature of the present disclosure, the polymer composition exhibits one or more of a hot creep of 175% or less after final cure as measured according to ICEA-T-28-562-2003 and a tensile strain at break of 20% or greater as measured according to ASTM D638-14.

[0020] According to a tenth feature of the present disclosure, a coated conductor includes: a conductor; and the polymer composition.

[0021] According to an eleventh feature of the present disclosure, the polymer composition of the coated conductor exhibits one or more of a thermal creep of 175% or less after final cure as measured according to ICEA-T-28-562-2003 and a tensile strain at break of 20% or greater as measured according to UL 2556 Section 3.5. DETAILED DESCRIPTION

[0022] As used herein, the term "and / or," when used in the context of a list of two or more items, means that any one of the listed items may be used alone, or any combination of two or more of the listed items may be used. For example, if a composition is described as containing components A, B, and / or C, the composition may 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.

[0023] Unless otherwise stated, all ranges are inclusive.

[0024] Test methods refer to the most recent test methods as of the priority date of this document, unless the date is expressed as a two-digit hyphenated test method number. Reference to a test method includes reference to both the testing association and the test method number. Test method organizations are referenced by one of the following abbreviations: ASTM refers to ASTM International (formerly the American Society for Testing and Materials); EN refers to European Standard; DIN refers to the German Institute for Standardization; and ISO refers to the International Organization for Standardization.

[0025] "Polymer" means a polymeric material prepared by polymerizing monomers, whether of the same or a different type.The generic term polymer thus encompasses the terms homopolymer, interpolymer, and copolymer.

[0026] "Ethylene polymer" means a polymer containing units derived from ethylene. Ethylene polymers typically contain at least 50% by weight of units derived from ethylene.

[0027] As used herein, unless otherwise indicated, the term weight percent ("wt%") refers to the weight percent of a component based on the total weight of the polymer composition.

[0028] As used herein, "CAS number" is a Chemical Abstracts Registration Number assigned by the Chemical Abstracts Service.

[0029] As used herein, the term "ambient conditions" is an air atmosphere having a temperature of 5°C to 50°C and a relative humidity of 5% to 100%.

[0030] polymer composition

[0031] The present disclosure relates to polymer compositions comprising an ethylene-silane copolymer comprising units derived from an ethylene monomer and a silane monomer, a Lewis acid catalyst, and a halogen-free flame retardant comprising a metal hydrate.

[0032] Ethylene-silane copolymer

[0033] The polymer composition comprises an ethylene-silane copolymer (a form of a silane-functionalized ethylene polymer). The ethylene-silane copolymer comprises units derived from ethylene monomers and silane monomers. "Copolymer" means a macromolecular compound prepared by reacting (i.e., polymerizing) two or more different types of monomers. The ethylene-silane copolymer is prepared by copolymerizing ethylene and silane monomers.

[0034] The polymer composition may comprise 10 wt % or more, or 15 wt % or more, or 20 wt % or more, or 25 wt % or more, or 30 wt % or more, or 35 wt % or more, or 40 wt % or more, or 45 wt % or more, or 50 wt % or more, or 55 wt % or more, or 60 wt % or more, or 65 wt % or more, or 70 wt % or more, or 75 wt % or more, or 80 wt % or more, or 85 wt % or more, based on the total weight of the polymer composition. % or more, while at the same time being 90 wt % or less, or 85 wt % or less, or 80 wt % or less, or 75 wt % or less, or 70 wt % or less, or 65 wt % or less, or 60 wt % or less, or 55 wt % or less, or 50 wt % or less, or 45 wt % or less, or 40 wt % or less, or 35 wt % or less, or 30 wt % or less, or 25 wt % or less, or 20 wt % or less, or 15 wt % or less of ethylene-silane copolymer.

[0035] The ethylene-silane copolymer has a density of 0.910 grams per cubic centimeter ("g / cc") or greater, or 0.915 g / cc or greater, or 0.920 g / cc or greater, or 0.921 g / cc or greater, or 0.922 g / cc or greater, or 0.925 g / cc to 0.930 g / cc or greater, or 0.935 g / cc or greater, while 0.940 g / cc or less, or 0.935 g / cc or less, or 0.930 g / cc or less, or 0.925 g / cc or less, or 0.920 g / cc or less, or 0.915 g / cc or less, as measured by ASTM D792.

[0036] The melt index of the ethylene-silane copolymer is measured according to ASTM D1238 at 190° C. / 2.16 kilogram (kg) weight and is reported in grams eluted per 10 minutes (g / 10 min). The melt index of the ethylene-silane copolymer may be 0.5 g / 10 min or greater, or 1.0 g / 10 min or greater, or 1.5 g / 10 min or greater, or 2.0 g / 10 min or greater, or 2.5 g / 10 min or greater, or 3.0 g / 10 min or greater, or 3.5 g / 10 min or greater, or 4.0 g / 10 min or greater, or 4.5 g / 10 min or greater, while 30.0 g / 10 min or less, or 25.0 g / 10 min or less. , or 20.0g / 10min or less, or 15.0g / 10min or less, or 10.0g / 10min or less, or 5.0g / 10min or less, or 4.5g / 10min or less, or 4.0g / 10min or less, or 3.5g / 10min or less, or 3.0g / 10min or less, or 2.5g / 10min or less, or 2.0g / 10min or less, or 1.5g / 10min or less, or 1.0g / 10min or less.

[0037] The ethylene-silane copolymer comprises 90 wt % or more, or 91 wt % or more, or 92 wt % or more, or 93 wt % or more, or 94 wt % or more, or 95 wt % or more, or 96 wt % or less, or 96.5 wt % or more, or 97 wt % or more, or 97.5 wt % or more, or 98 wt % or more, or 99 wt % or more, while at the same time being 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 of alpha olefins (α-olefins), as measured using Fourier transform infrared (FTIR) spectroscopy. The α-olefins may include C2, or C3 to C4, or C6, or C8, or C 10 , or C 12 , or C 16 , or C 18 , or C 20Alpha-olefins, such as ethylene, propylene, 1-butene, 1-hexene, 4-methyl-1-pentene and 1-octene. Other units of ethylene-silane copolymers can be derived from one or more polymerizable monomers, including but not limited to unsaturated esters (that is, the term "ethylene-silane copolymer" as used herein also encompasses ethylene-silane-unsaturated ester terpolymers). Unsaturated esters can be alkyl acrylates, alkyl methacrylates or vinyl carboxylates. The alkyl group can have 1 to 8 carbon atoms, or 1 to 4 carbon atoms. The carboxylate group can have 2 to 8 carbon atoms, or 2 to 5 carbon atoms. The example of acrylate and methacrylate includes but is not limited to ethyl acrylate, methyl acrylate, methyl methacrylate, tert-butyl acrylate, n-butyl acrylate, n-butyl methacrylate and 2-ethylhexyl acrylate. The example of vinyl carboxylates includes but is not limited to vinyl acetate, vinyl propionate and vinyl butyrate.

[0038] The ethylene-silane copolymer may contain 0.40 mol% to 1.00 mol% of the copolymerized silane. For example, the ethylene-silane copolymer may contain 0.40 mol% or more, or 0.42 mol% or more, or 0.44 mol% or more, or 0.45 mol% or more, or 0.46 mol% or more, or 0.48 mol% or more, or 0.50 mol% or more, or 0.55 mol% or more, or 0.60 mol% or more, or 0.65 mol% or more, or 0.70 mol% or more, or 0.75 mol% or more, or 0.80 mol% or more, or 0.85 mol% or more, or 0.90 mol% or more, or 0.96 mol% or more, or 0.10 mol% or more. % or less, or 0.95 mol % or less, or 0.90 mol % or less, or 0.85 mol % or less, or 0.80 mol % or less, or 0.75 mol % or less, or 0.70 mol % or less, or 0.65 mol % or less, or 0.60 mol % or less, or 0.55 mol % or less, or 0.50 mol % or less, or 0.48 mol % or less, or 0.46 mol % or less, or 0.45 mol % or less, or 0.44 mol % or less, or 0.42 mol % or less of copolysilane. The amount of copolysilane present in the ethylene-silane copolymer is determined by the Silane Test explained in more detail below.

[0039] The silane comonomer used to prepare the ethylene-silane copolymer can be a hydrolyzable silane monomer. A "hydrolyzable silane monomer" is a silane-containing monomer that will effectively copolymerize with an α-olefin (e.g., ethylene) to form an α-olefin / silane copolymer (such as an ethylene-silane copolymer). The hydrolyzable silane monomer has structure (I):

[0040]

[0041] where R 1 is a hydrogen atom or a methyl group; x is 0 or 1; n is an integer from 1 to 4 or 6 or 8 or 10 or 12; and each R 2 are independently hydrolyzable organic groups, such as alkoxy groups having 1 to 12 carbon atoms (e.g., methoxy, ethoxy, butoxy), aryloxy groups (e.g., phenoxy), aralkyloxy groups (e.g., benzyloxy), aliphatic acyloxy groups having 1 to 12 carbon atoms (e.g., formyloxy, acetoxy, propionyloxy), amino or substituted amino groups (e.g., alkylamino, arylamino), or lower alkyl groups having 1 to 6 carbon atoms, provided that the three R 2 No more than one of the groups is an alkyl group. The hydrolyzable silane monomer can be copolymerized with an α-olefin (e.g., ethylene) in a reactor (e.g., a high-pressure process) to form an α-olefin-silane reactor copolymer. In the example where the α-olefin is ethylene, such a copolymer is referred to herein as an ethylene-silane copolymer.

[0042] The hydrolyzable silane monomer may include a silane monomer comprising an ethylenically unsaturated hydrocarbon group such as a vinyl, allyl, isopropenyl, butenyl, cyclohexenyl, or γ-(meth)acryloyloxyallyl group and a hydrolyzable group such as, for example, a hydrocarbonoxy, hydrocarbon acyloxy, or hydrocarbon amino group. The hydrolyzable group may include a methoxy, ethoxy, formyloxy, acetoxy, propionyloxy, and an alkyl or arylamino group. In a specific example, the hydrolyzable silane monomer is an unsaturated alkoxysilane that can be grafted onto a polyolefin or copolymerized with an α-olefin such as ethylene in a reactor. Examples of hydrolyzable silane monomers include vinyltrimethoxysilane ("VTMS"), vinyltriethoxysilane ("VTES"), vinyltriacetoxysilane, and γ-(meth)acryloyloxypropyltrimethoxysilane. In the context of structure (I), for VTMS: x = 0; R 1 = hydrogen; and R 2 = methoxy; for VTES: x = 0; R 1 = hydrogen; and R 2 =ethoxy; and for vinyltriacetoxysilane: x=0; R 1 =H; and R 2 =acetoxy.

[0043] The ethylene-silane copolymer can have a crystallinity at 23° C. of 40% to 46% by weight, as measured according to the Crystallinity Test provided below. For example, the ethylene-silane copolymer can have a crystallinity at 23° C. of 40.0% or more, or 40.5% or more, or 41.0% or more, or 41.5% or more, or 42.0% or more, or 42.5% or more, or 43.0% or more, or 43.5% or more, or 44.0% or more, or 44.5% or more, or 45.0% or more, as measured according to the Crystallinity Test. % or less, or 45.5 wt % or more, while at the same time 46.0 wt % or less, or 45.5 wt % or less, or 45.0 wt % or less, or 44.5 wt % or less, or 44.0 wt % or less, or 43.5 wt % or less, or 43.0 wt % or less, or 42.5 wt % or less, or 42.0 wt % or less, or 41.5 wt % or less, or 41.0 wt % or less, or 40.5 wt % or less.

[0044] Non-silane functionalized ethylene polymers

[0045] The polymer composition may comprise one or more non-silane functionalized ethylene polymers. The non-silane functionalized ethylene polymers may comprise ethylene and one or more C3-C 20 α-olefin comonomers such as propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, and 1-octene. In one embodiment, the ethylene polymer without silane functionalization is a homopolymer. In one embodiment, the ethylene polymer without silane functionalization is an ethylene / α-olefin copolymer. In one embodiment, the ethylene polymer without silane functionalization is an ethylene / unsaturated ester copolymer. The unsaturated ester can be an alkyl acrylate, an alkyl methacrylate, or a vinyl carboxylate. The alkyl group can have 1 to 8 carbon atoms, or 1 to 4 carbon atoms. The carboxylate group can have 2 to 8 carbon atoms, or 2 to 5 carbon atoms. Examples of acrylates and methacrylates include, but are not limited to, ethyl acrylate, methyl acrylate, methyl methacrylate, tert-butyl acrylate, n-butyl acrylate, n-butyl methacrylate, and 2-ethylhexyl acrylate. Examples of vinyl carboxylates include, but are not limited to, vinyl acetate, vinyl propionate, and vinyl butyrate. The non-silane functionalized ethylene polymers can have a unimodal or multimodal molecular weight distribution and can be used alone or in combination with one or more other types of ethylene polymers (e.g., a blend of two or more ethylene polymers that differ from one another in monomer composition and content, catalytic preparation method, molecular weight, molecular weight distribution, density, etc.). If a blend of ethylene polymers is employed, the polymers can be blended by any in-reactor or post-reactor method.

[0046] The non-silane-functionalized ethylene polymer may comprise 50 wt % or more, 60 wt % or more, 70 wt % or more, 80 wt % or more, 85 wt % or more, 90 wt % or more, or 91 wt % or more, or 92 wt % or more, or 93 wt % or more, or 94 wt % or more, or 95 wt % or more, or 96 wt % or more, or 97 wt % or more, or 97.5 wt % or more, or 98 wt % or more, or 99.6 wt % or more, or 10 ... % or less, or 99 wt % or more, while at the same time being 100 wt % or less, or 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. Other units of the ethylene-based polymer may include C3, or C4, or C6, or C8, or C 10 , or C 12 , or C 16 , or C 18 , or C 20 α-Olefins such as propylene, 1-butene, 1-hexene, 4-methyl-1-pentene and 1-octene.

[0047] The polymer composition can comprise from 0% to 60% by weight of the ethylene polymer that is not silane-functionalized. For example, the polymer composition comprises 0% by weight or more, or 5% by weight or more, or 10% by weight or more, or 15% by weight or more, or 20% by weight or more, or 25% by weight or more, or 30% by weight or more, or 35% by weight or more, or 40% by weight or more, or 45% by weight or more, or 50% by weight or more, or 55% by weight or more, while at the same time 60% by weight or less, or 55% by weight or less, or 50% by weight or less, or 45% by weight or less, or 40% by weight or less, or 35% by weight or less, or 30% by weight or less, or 25% by weight or less, or 20% by weight or less, or 15% by weight or less, or 10% by weight or less, or 5% by weight or less of the ethylene polymer that is not silane-functionalized.

[0048] Non-limiting examples of ethylene polymers that are not silane functionalized are low density polyethylene (LDPE), linear low density polyethylene (LLDPE), high density polyethylene (HDPE), ethylene vinyl acetate (EVA) copolymers, ethylene ethyl acrylate (EEA) copolymers, and various elastomers such as ENGAGE ® available from The Dow Chemical Company. TM and INFUSE TM resin).

[0049] Halogen-free flame retardants

[0050] The polymer composition includes a halogen-free flame retardant. The halogen-free flame retardant of the polymer composition can inhibit, curb or delay the generation of flames. As used herein, "halogen-free" and similar terms mean that the flame retardant filler has no or substantially no halogen content as measured by ion chromatography (IC) or similar analytical methods, that is, each kg of flame retardant filler contains less than 10,000 mg of halogen. A halogen content less than this amount is considered to be insignificant to the efficacy of the flame retardant filler in, for example, a coated conductor. Examples of halogen-free flame retardants suitable for polymer compositions include, but are not limited to, metal hydrates (such as aluminum hydroxide, magnesium hydroxide), metal carbonates, red phosphorus, silicon dioxide, aluminum oxide, brucite (mineral form of magnesium hydroxide), titanium oxide, carbon nanotubes, talc, clay, organically modified clay, calcium carbonate, zinc borate, antimony trioxide, wollastonite, mica, ammonium octamolybdate, glass frit, hollow glass microspheres, expansion compounds, expanded graphite, and combinations thereof. In one embodiment, the halogen-free flame retardant is selected from the filler with hydroxide moiety (such as metal hydrate) and / or hydroxyl group (such as silicon dioxide). In one embodiment, the metal hydrate of halogen-free flame retardant can be selected from the group consisting of the following: aluminum hydroxide, magnesium hydroxide, calcium hydroxide, zinc hydroxide, ferric hydroxide, copper hydroxide and their combination. In one embodiment, the halogen-free flame retardant is selected from the group consisting of metal hydrate, silicon dioxide and their combination. Halogen-free flame retardant can optionally be surface treated (coated) with a saturated or unsaturated carboxylic acid or a metal salt of the acid having 8 to 24 carbon atoms or 12 to 18 carbon atoms. Exemplary surface treatment is described in US 4,255,303, US 5,034,442, US 7,514,489, US2008 / 0251273 and WO 2013 / 116283. Alternatively, acid or salt can be added to the composition only in a similar amount without using a surface treatment procedure. Other surface treatments known in the art may also be used, including silanes, titanates, phosphates, and zirconates.

[0051] Examples of commercially available halogen-free flame retardants suitable for use in the polymer composition include, but are not limited to, APYRAL® available from Nabaltec AG. TM 40CD aluminum hydroxide, MAGNIFIN available from Magnifin Magnesiaprodukte GmbH & Co KG TM H5 magnesium hydroxide, Microcarb 95T ultramicronized and treated calcium carbonate available from Reverte, and combinations thereof.

[0052] The polymer composition may contain the polyol at a concentration of 10 wt % or more, or 12 wt % or more, or 14 wt % or more, or 16 wt % or more, or 18 wt % or more, or 20 wt % or more, or 22 wt % or more, or 24 wt % or more, or 26 wt % or more, or 28 wt % or more, or 30 wt % or more, or 32 wt % or more, or 34 wt % or more, or 36 wt % or more, or 38 wt % or more, 40 wt % or more, or 41 wt % or more, or 42 wt % or more, or 43 wt % or more, or 44 wt % or more, or 46 wt % or more, or 47 wt % or more, or 48 wt % or more, or 49 wt % or more, or 50 wt % or more, or 51 wt % or more, or 52 wt % or more, or 53 wt % or more, or 54 wt % or more, or 55 wt % or more, or 56 wt % or more, or 57 wt % or more, or 58 wt % or more, or 59 wt % or more, or 60 wt % or more, or 61 wt % or more, or 62 wt % or more, or 63 wt % or more, or 64 wt % or more, or 65 wt % or more, or 66 wt % or more, or 67 wt % or more, or 68 wt % or more, or 69 wt % or more, or 70 wt % or more, or 71 wt or 42 wt % or more, or 44 wt % or more, or 46 wt % or more, or 48 wt % or more, or 50 wt % or more, or 52 wt % or more, or 54 wt % or more, or 56 wt % or more, or 58 wt % or more, or 60 wt % or more, or 62 wt % or more, or 64 wt % or more, or 66 wt % or more, or 68 wt % or more, or 70 wt % or more, or 72 wt % or more, or 74 wt % or more, or 76 wt % or more, or 78 % or more, while at the same time 80 % or less, or 78 % or less, or 76 % or less, or 74 % or less, or 72 % or less, or 70 % or less, or 68 % or less, or 66 % or less, or 64 % or less, or 62 % or less, or 60 % or less, or 58 % or less, or 56 % or less, or 54 % or less, or 52 % or less, or 50 % or less, or 48 % or less, or 46 % or less. % or less, or 44 wt % or less, or 42 wt % or less, or 40 wt % or less, or 38 wt % or less, or 36 wt % or less, or 34 wt % or less, or 32 wt % or less, or 30 wt % or less, or 28 wt % or less, or 26 wt % or less, or 24 wt % or less, or 22 wt % or less, or 20 wt % or less, or 18 wt % or less, or 16 wt % or less, or 14 wt % or less, or 12 wt % or less of a halogen-free flame retardant.

[0053] The polymer composition may exhibit a filler to catalyst weight ratio of 75 to 1000. For example, the filler to catalyst weight ratio may be 75 or greater, or 100 or greater, or 125 or greater, or 150 or greater, or 1 ... 0 or greater, or 125 or greater, or 150 or greater, or 175 or greater, or 100 or greater, or 125 or greater, or 150 or greater, or 175 or greater, or 100 or greater, or 125 or greater, or 150 or greater, or 175 or greater, or 100 or greater, or 125 or greater, or 150 or greater, or 175 or greater, or 100 or greater, or 125 or greater, or 150 or greater, or 175 or greater 5 or more, while at the same time 1000 or less, or 975 or less, or 950 or less, or 925 or less, or 900 or less, or 875 or less, or 850 or less, or 825 or less, or 800 or less, or 775 or less, or 750 or less, or 725 or less, or 700 or less, or 675 or less, or 650 or less, or 625 or less, or 600 or less, or 575 or less, or less, or 550 or less, or 525 or less, or 500 or less, or 475 or less, or 450 or less, or 425 or less, or 400 or less, or 375 or less, or 350 or less, or 325 or less, or 300 or less, or 275 or less, or 250 or less, or 225 or less, or 200 or less, or 175 or less, or 150 or less, or 125 or less, or 100 or less. The weight ratio of filler to catalyst is calculated by dividing the total weight % of all combined fillers present in the polymer composition by the total weight % of Lewis acid catalyst in the polymer composition.

[0054] additive

[0055] Polymer composition can comprise one or more additives.The non-limiting example of suitable additive comprises antioxidant, moisture scavenger, colorant, corrosion inhibitor, lubricant, silanol condensation catalyst, ultraviolet (UV) absorber or stabilizer, antiblocking agent, flame retardant, coupling agent, compatibilizer, plasticizer, filler, processing aid, propylene polymer (homopolymer and copolymer, comprising polypropylene homopolymer, random copolymer polypropylene and impact copolymer polypropylene) and their combination.The non-limiting example of suitable moisture scavenger comprises alkyl alkoxy silane class and their combination.The non-limiting example of alkyl alkoxy silane class comprises octyl triethoxy silane, octyl trimethoxy silane and hexadecyl trimethoxy silane.In one embodiment, moisture scavenger is octyl triethoxy silane. The moisture scavenger is present in an amount of 0 wt %, or 0.01 wt % or more, or 0.03 wt % or more, or 0.05 wt % or more, or 0.1 wt % or more, or 0.3 wt % or more, or 0.5 wt % to 1.0 wt %, or 1.0 wt % or more, or 2.0 wt % or more, or 3.0 wt % or more, or 4.0 wt % or more, or 5.0 wt % or more, based on the total weight of the polymer composition. In another embodiment, the moisture scavenger is present in an amount of 0 wt %, or 0.01 wt % to 5.0 wt %, or 0.05 wt % to 3.0 wt %, or 0.1 wt % to 2.0 wt %, or 0.3 wt % to 1.0 wt %, based on the total weight of the polymer composition.

[0056] The polymer composition may include an antioxidant. Non-limiting examples of suitable antioxidants include phenolic antioxidants, sulfur antioxidants, phosphate antioxidants, and hydrazine metal passivators. Suitable phenolic antioxidants include high molecular weight hindered phenols, methyl substituted phenols, phenols with primary or secondary carbonyl substituents, and polyfunctional phenols such as sulfur- and phosphorus-containing phenols. Representative hindered phenols include 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene; pentaerythritol tetrakis-3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate; n-octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate; 4,4'-methylenebis(2,6-tert-butyl-phenol); 4,4'-thiobis(6-tert-butyl-o-cresol)2,6-di-tert-butylphenol;

[0057] 6-(4-hydroxyphenoxy)-2,4-bis(n-octyl-thio)-l,3,5-triazine; 3,5-di-tert-butyl-4-hydroxybenzoic acid (di-n-octylthio) ethyl ester; and hexa[3-(3,5-di-tert-butyl-4-hydroxy-phenyl)-propionic acid] sorbitol ester. The polymer composition may include pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, which may be Irganox TM1010 is commercially available from BASF. The non-limiting example of a suitable methyl-substituted phenol is isobutylidene bis (4,6-dimethylphenol). The non-limiting example of a suitable hydrazine-based metal deactivator is oxalyl bis (benzylidene hydrazide). Based on the gross weight of the polymer composition, the polymer composition may include 0 wt %, or 0.001 wt %, or 0.01 wt %, or 0.02 wt %, or 0.05 wt %, or 0.1 wt %, or 0.2 wt %, or 0.3 wt %, or 0.4 wt % to 0.5 wt %, or 0.6 wt %, or 0.7 wt %, or 0.8 wt %, or 1.0 wt %, or 2.0 wt %, or 2.5 wt %, or 3.0 wt % of an antioxidant.

[0058] The polymer composition can include a silanol condensation catalyst, such as a Lewis acid. A "silanol condensation catalyst" promotes the crosslinking of silane-functionalized polyolefins by hydrolysis and condensation reactions. A Lewis acid is a chemical species that can accept an electron pair from a Lewis base. A Lewis base is a chemical species that can accept an electron pair from a Lewis base. Non-limiting examples of suitable Lewis acids include tin carboxylates such as dibutyltin dilaurate (DBTDL), dioctyltin dilaurate, aluminum chloride, titanium chloride, zinc chloride, dimethylhydroxytin oleate, dioctyltin maleate, di-n-butyltin maleate, dibutyltin diacetate, dibutyltin dioctoate, stannous acetate, stannous octoate, and various other organometallic compounds such as lead naphthenate, zinc octoate, and cobalt naphthenate, and combinations thereof. The polymer composition comprises 0 wt %, or 0.001 wt %, or 0.005 wt %, or 0.01 wt %, or 0.02 wt %, or 0.03 wt % to 0.05 wt %, or 0.1 wt %, or 0.2 wt %, or 0.5 wt %, or 1.0 wt %, or 3.0 wt %, or 5.0 wt % or 10 wt % of a silanol condensation catalyst based on the gross weight of the polymer composition. Typically a silanol condensation catalyst is added to a product manufacturing extruder (such as during cable manufacturing) so that it is present in the final melt extrusion process. Therefore, the silane-functionalized polyolefin can undergo a certain degree of crosslinking before leaving the extruder, and crosslinking is typically completed after leaving the extruder when exposed to humidity (e.g., a sauna, hot bath, or cooling bath) and / or the humidity present in the environment of storage, transportation, or use.

[0059] The Lewis acid silanol condensation catalyst may be included in a catalyst masterbatch blend and the catalyst masterbatch is included in the composition. Non-limiting examples of suitable silanol condensation catalyst masterbatches include those sold by The Dow Chemical Company under the trade name SI-LINK TM Those sold, including SI-LINK TM DFDB-5480NT and SI-LINK TMIn one embodiment, the composition comprises from 0 wt%, or 0.001 wt%, or 0.01 wt%, or 0.5 wt%, or 1.0 wt%, or 2.0 wt%, or 3.0 wt%, or 4.0 wt% to 5.0 wt%, or 6.0 wt%, or 7.0 wt%, or 8.0 wt%, or 9.0 wt%, or 10.0 wt%, or 15.0 wt%, or 20.0 wt% of a silanol condensation catalyst masterbatch, based on the total weight of the composition.

[0060] The polymer composition may include an ultraviolet (UV) absorber or stabilizer. Non-limiting examples of suitable UV stabilizers are hindered amine light stabilizers (HALS). Non-limiting examples of suitable HALS are 1,3,5-triazine-2,4,6-triamine, N,N-1,2-ethanediylbis-N-3-4,6-dibutyl(1,2,2,6,6-pentamethyl-4-piperidinyl)amino-1,3,5-triazin-2-ylaminopropyl-N,N-dibutyl-N,N-bis(1,2,2,6,6-pentamethyl-4-piperidinyl)-1,5,8,12-tetrakis[4,6-bis(n-butyl-n-1,2,2,6,6-pentamethyl-4-piperidinylamino)-1,3,5-triazin-2-yl]-1,5,8,12-tetraazadodecane, which is a SABO. TM STAB UV-119 is commercially available from SABO SpA (Levate, Italy). In one embodiment, the composition contains 0 wt%, or 0.001 wt%, or 0.002 wt%, or 0.005 wt%, or 0.006 wt%, or 0.007 wt%, or 0.008 wt%, or 0.009 wt%, or 0.01 wt%, or 0.2 wt%, or 0.3 wt%, or 0.4 wt%, or 0.5 wt%, 1.0 wt%, or 2.0 wt%, or 2.5 wt%, or 3.0 wt% UV absorber or stabilizer, based on the total weight of the composition.

[0061] The composition may include a processing aid. Non-limiting examples of suitable processing aids include oils, organic acids (such as stearic acid) and metal salts of organic acids (such as zinc stearate). In one embodiment, based on the gross weight of the composition, the composition includes 0 wt%, or 0.01 wt%, or 0.02 wt%, or 0.05 wt%, or 0.07 wt%, or 0.1 wt%, or 0.2 wt%, or 0.3 wt%, or 0.4 wt% to 0.5 wt%, or 0.6 wt%, or 0.7 wt%, or 0.8 wt%, or 1.0 wt%, or 2.0 wt%, or 2.5 wt%, or 3.0 wt%, or 5.0 wt%, or 10.0 wt%, or 20.0 wt% of a processing aid.

[0062] The composition can include 0 wt% or more, or 0.001 wt% or more, or 0.002 wt% or more, or 0.005 wt% or more, or 0.006 wt% or more, or 0.008 wt% or more, or 0.009 wt% or more, or 0.01 wt% or more, or 0.2 wt% or more, or 0.3 wt% or more, or 0.4 wt% or more, or 0.5 wt% or more, or 1.0 wt% or more, or 2.0 wt% or more, or 3.0 wt% or more, or 4.0 wt% or more, or 5.0 wt% or more, or 10.0 wt% or more, or 15.0 wt% or more, or 20.0 wt% or more, or 30 wt% or more, or 40 wt% or more, or 50 wt% or more of additives, based on the total weight of the polymer composition.

[0063] Masterbatch

[0064] One or more of the ethylene-silane copolymer, halogen-free flame retardant, and additives can be combined into a premixed masterbatch. Such a masterbatch is typically formed by dispersing the flame retardant and additive into an inert plastic resin. The masterbatch is preferably formed by melt compounding.

[0065] One or more of the components or masterbatches can be dried prior to compounding or extrusion, or the mixture of components or masterbatches can be dried after compounding or extrusion to reduce or eliminate potential scorch (i.e., premature crosslinking during compounding or extrusion) that may be caused by moisture present in or associated with a component, such as a filler. The composition can be prepared in the absence of a silanol condensation catalyst to extend shelf life, and the silanol condensation catalyst can be added as a final step in preparing a cable construction (coated conductor) by an extrusion process. Alternatively, the catalyst can be combined with one or more other components in the form of a masterbatch.

[0066] Coated conductor

[0067] The present disclosure also provides a coated conductor. The coated conductor includes a conductor and a coating on the conductor, the coating comprising a polymer composition. The polymer composition is at least partially disposed around the conductor to produce the coated conductor. The conductor may include a conductive metal and / or an optical waveguide.

[0068] A method for producing a coated conductor comprises mixing and heating a polymer composition in an extruder to at least the melting temperature of the ethylene-silane polymer to form a polymer melt blend, and then applying the polymer melt blend to a conductor. The term "onto" includes direct or indirect contact between the polymer melt blend and the conductor. The polymer melt blend is in an extrudable state.

[0069] The polymer composition is disposed 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 completely or partially cover or otherwise surround or encase the conductor. The coating may be the sole component surrounding the conductor as an insulating material or jacket. Alternatively, the coating may be a layer of a multi-layer jacket or sheath surrounding the conductor. The coating may be in direct contact with the conductor. The coating may be in direct contact with the insulating layer surrounding the conductor.

[0070] The resulting coated conductor is cured under humid conditions for a sufficient period of time to allow the coating to achieve the desired degree of crosslinking. The temperature during curing is typically above 0°C. In one embodiment, curing is performed in a 90°C water bath for at least 4 hours. In one embodiment, curing is performed for up to 200 days under ambient conditions, including an air atmosphere, ambient temperature (e.g., 5°C to 50°C), and ambient relative humidity (e.g., 5% to 100% relative humidity (%RH)).

[0071] In one embodiment, the polymer composition is applied to a 10 American wire gauge ("AWG") conductor (diameter: 2.59 mm) at a thickness of 1.524 mm.

[0072] The polymer composition coating the conductor may exhibit a tensile strain at break of 20% or greater as measured in accordance with UL 2556, Section 3.5. For example, the polymer composition coating the conductor may exhibit a tensile strain at break of 20% or greater, or 25% or greater, or 30% or greater, or 40% or greater, or 50% or greater, or 60% or greater, or 70% or greater, or 80% or greater, or 90% or greater, or 100% or greater, or 150% or greater, or 200% or greater, or 250% or greater, or 300% or greater, or 400% or greater, or 500% or greater, while at the same time being 600% or less, or 500% or less, or 400% or less, or 300% or less, or 250% or less, or 200% or less, or 150% or less, or 100% or less, as measured in accordance with UL 2556, Section 3.5. The conductor-coated polymer composition may exhibit a thermal creep of 175% or less after final cure as measured in accordance with UL 2556, Section 7.9 or ICEA-T-28-562-2003. For example, the conductor-coated polymer composition may exhibit a thermal creep of 175% or less, or 150% or less, or 125% or less, or 100% or less, or 75% or less, or 50% or less, or 25% or less, or 10% or less after final cure as measured in accordance with UL 2556, Section 7.9 or ICEA-T-28-562-2003.

[0073] The polymer composition prepared in the form of extruded tapes or compression molded specimens can have a tensile strain at break as measured according to ASTM D638-14 of 20% or greater. For example, an extruded tape or compression molded specimen made from the polymer composition may exhibit a tensile strain at break of 20% or greater, or 25% or greater, or 30% or greater, or 40% or greater, or 50% or greater, or 60% or greater, or 70% or greater, or 80% or greater, or 90% or greater, or 100% or greater, or 150% or greater, or 200% or greater, or 250% or greater, or 300% or greater, or 400% or greater, or 500% or greater, while at the same time being 600% or less, or 500% or less, or 400% or less, or 300% or less, or 250% or less, or 200% or less, or 150% or less, or 100% or less, as measured according to ASTM D638-14.

[0074] The polymer composition prepared in the form of an extruded tape or a compression molded sample may have a thermal creep of 175% or less after final cure as measured in accordance with UL 2556, Section 7.9 or ICEA-T-28-562-2003. For example, an extruded tape or a compression molded sample made from the polymer composition may exhibit a thermal creep of 175% or less, or 150% or less, or 125% or less, or 100% or less, or 75% or less, or 50% or less, or 25% or less, or 10% or less after final cure as measured in accordance with UL 2556, Section 7.9 or ICEA-T-28-562-2003.

[0075] Example

[0076] Test Method

[0077] Density: Density was measured according to ASTM D792, Method B. Results are reported in grams (g) per cubic centimeter (g / cc).

[0078] Melt Index: Melt index (MI) is measured according to ASTM D1238, Condition 190°C / 2.16 kilogram (kg) weight and is reported in grams eluted per 10 minutes (g / 10 min).

[0079] Silane Test: X-ray fluorescence spectroscopy ("XRF") was used to determine the weight percent (wt%) of the silicon atom (Si) content of the silane comonomer units in the test sample of ethylene-silane copolymer, and then the wt% of the silane comonomer units in the test sample of ethylene-silane copolymer was calculated. The test sample in powder form was pressed at 8.3 megapascals (MPa; 1,200 pounds per square inch (psi)) for 1 minute using a Buehler SimpliMet 300 automatic mounting press preheated at 115.6° C. (240° F.) for 3 minutes to form a plaque having a thickness of approximately 6 mm, and the plaque was cooled to 25° C. The Si atom content of the plaque was analyzed by wavelength dispersive XRF using a wavelength dispersive X-ray fluorescence spectrometer from PANalytical Axios. The Si atom content is determined by comparing its line intensity in the XRF spectrum with a calibration curve for Si atom content, which is established using polymer standards of known Si atom concentration, as independently measured using neutron activation analysis (NAA) or inductively coupled plasma (ICP) methods. The weight percent of hydrolyzable silyl group comonomer units (i.e., the weight percent of hydrolyzable silyl groups) in the ethylene-silane copolymer is calculated using the XRF-measured Si atom weight percent value and the molecular weight of at least one silane comonomer from which the hydrolyzable silyl groups are derived. For hydrolyzable silyl groups derived from vinyltrimethoxysilane (VTMS), a VTMS molecular weight of 148.23 g / mol is used. To calculate the hydrolyzable silyl group content (wt %) of the hydrolyzable silyl group comonomer units in the ethylene-silane copolymer, the Si atom wt % ("C") obtained from XRF and the following formula are used: p = C*(m / 28.086)(1 / 10000 ppmw), where * represents multiplication, / represents division, p is the wt % of hydrolyzable silyl groups in the ethylene-silane copolymer, C is the Si atomic weight (XFR) in parts per million by weight (ppmw), m is the molecular weight in g / mol of the silane comonomer from which the hydrolyzable silyl groups are derived, 28.086 is the atomic weight of silicon atoms, and 10000 ppmw is the number of parts per million by weight representing 1.00 wt %. For example, when XRF shows that the Si atoms in the ethylene-silane copolymer are 379 ppmw and the comonomer used to prepare the ethylene-silane copolymer is VTMS with a molecular weight of 148.23 g / mol, the wt% comonomer content is 0.20 wt%.To calculate the mol% of hydrolyzable silyl group comonomer units in the ethylene-silane copolymer for the silane comonomer used, the calculated weight % of hydrolyzable silyl group comonomer units in the ethylene-silane copolymer and the following formula are used: G = 100*(p / m) / [(p / m) + (100.00 wt% - p) / 28.05 g / mol], where * represents multiplication, G is the mole percent (mol%) of hydrolyzable silyl groups in the ethylene-silane copolymer; p is the weight % of the hydrolyzable silyl groups in the ethylene-silane copolymer, m is the molecular weight in g / mol of the silane comonomer from which the hydrolyzable silyl groups are derived, and 28.05 g / mol is the molecular weight of the monomer ethylene (H2C=CH2). For example, when the comonomer content is 2.0 wt% and the comonomer is VTMS, p = 2.0 wt% and m = 148.23 g / mol, and G = 0.38 mol%. When the comonomer content is 5.0 wt% and the comonomer is VTMS, p = 5.0 wt%, m = 148.23 g / mol, and G = 0.99 mol%. When two or more silane comonomers having different molecular weights are used to prepare an ethylene-silane copolymer, the molecular weight used to calculate the total mol% of all hydrolyzable silyl groups in the ethylene-silane copolymer is the weight-average molecular weight of the comonomers. The weights can be determined by the ratio of the amounts of comonomers fed to the reactor, by measuring the relative amounts of different comonomer units in the ethylene-silane copolymer when each hydrolyzable silyl group is bonded to a different type of carbon atom (e.g., tertiary versus secondary carbon atoms) by NMR spectroscopy, or by calibration using Fourier transform infrared (FT-IR) spectroscopy to provide quantification of the different types of comonomers.

[0080] Crystallinity Test: A differential scanning calorimeter (DSC) instrument, DSC Q1000 (TA Instruments), was used to determine the melting peak and percent (%) or weight percent (wt%) crystallinity of ethylene polymers at 23°C. (A) Baseline calibrate the DSC instrument. Use the software calibration wizard. Obtain a baseline by heating the cell from -80°C to 280°C in an aluminum DSC pan without any sample. Then use a sapphire standard as indicated by the calibration wizard. Analyze 1 milligram (mg) to 2 mg of fresh indium sample by heating the standard sample to 180°C, cooling to 120°C at a cooling rate of 10°C / min, then isothermally holding the standard sample at 120°C for 1 minute, and then heating the standard sample from 120°C to 180°C at a heating rate of 10°C / min. The heat of fusion of the indium standard sample was determined to be 28.71 ± 0.50 joules / gram (J / g) and the onset of melting was determined to be 156.6°C ± 0.5°C. (B) DSC measurement is performed on the test sample using a DSC instrument calibrated with baseline. At a temperature of 160°C, the test sample of the semi-crystalline ethylene polymer is pressed into a film. 5mg to 8mg of the test sample film is weighed in an aluminum DSC pan. The lid is pressed on the pan to seal the pan and ensure a closed atmosphere. The pan sealed with the lid is placed in a DSC cell, the cell is balanced at 30°C, then heated to 190°C at a rate of about 100°C / min, the sample is kept at 190°C for 3 minutes, the sample is cooled to -60°C at a rate of 10°C / min to obtain a cooling curve melting heat (Hf), and isothermally kept at -60°C for 3 minutes. The sample is then heated to 190°C again at a rate of 10°C / min to obtain a second heating curve melting heat (ΔHf). Using the second heating curve, the heat of fusion is measured from -20°C (in ethylene homopolymers, copolymers of ethylene and hydrolyzable silane monomers, and densities greater than or equal to 0.90g / cm 3 of ethylene α-olefin copolymers) or -40°C (in the case of copolymers of ethylene and unsaturated esters, and density less than 0.90 g / cm 3The "total" heat of fusion (J / g) is calculated by integrating the heat of fusion from 23°C (room temperature) to the melting endpoint using the second heating curve by plummeting at 23°C. The "total crystallinity" (calculated from the "total" heat of fusion) and the "crystallinity at room temperature" (calculated from the 23°C heat of fusion) are measured and reported. Crystallinity is measured from the second heating curve heat of fusion (ΔHf) of the test specimen and reported as the percentage (%) or weight percent (wt%) crystallinity of the polymer and normalized to the heat of fusion of 100% crystalline polyethylene, where % crystallinity or wt% crystallinity = (ΔHf*100%) / 292 J / g, where ΔHf is as defined above, * represents mathematical multiplication, / represents mathematical division, and 292 J / g is the literature value for the heat of fusion (ΔHf) of 100% crystalline polyethylene.

[0081] Thermal creep: Thermal creep (also called thermal creep elongation) of the polymer composition is measured after final curing has taken place and is measured according to UL 2556 Section 7.9 or ICEA-T-28-562-2003 at a specified temperature (200°C or 150°C) under a fixed stress (0.2 MPa).

[0082] Tensile Peak Stress and Tensile Strain at Break: In the case of coated conductors, the tensile peak stress (also known as tensile strength) and tensile strain at break (also known as tensile elongation) of the polymer composition are measured in accordance with Underwriters Laboratories ("UL") 2556, Section 3.5, at a displacement rate of 20 inches per minute and at 23° C. and 50% relative humidity. The average of four or five measurements is determined. Each test specimen is prepared by removing the polymer composition coating (insulation material) from a coated conductor that has undergone final curing without damaging it. The tensile properties of extruded tapes or compression molded specimens made from the polymer composition can also be measured in accordance with ASTM D638-14 at a displacement rate of 20 inches per minute (using Type IV dog-bone specimens obtained from the tapes or compression molded specimens).

[0083] Char Length and Filler-Weighted Char Length (FWCL) Values: The FWCL value of a coated conductor is determined by first conducting International Electrotechnical Commission Test 60332-1-2:2004, which specifies a procedure for testing the resistance of a single vertical coated conductor to vertical flame propagation. Test 60332-1-2:2004 measures the length of char formed on the coated conductor during the test ("Char Length"). The FWCL value is calculated by multiplying the char length in centimeters by the weight percent of flame-retardant filler present in the polymer composition used to form the coated conductor and dividing by 100.

[0084] Material

[0085] The materials used in the inventive examples ("IE") and comparative examples ("CE") are provided below.

[0086] ESC1 is an ethylene-silane copolymer ("ESC") characterized by a melt index (I2) of 2.0 g / 10 minutes, a density of 0.922 g / cc, a copolymerized VTMS content of 0.65 mol%, and a crystallinity of 44.58 wt% at 23° C. ESC1 is commercially available from The Dow Chemical Company, Midland, Michigan.

[0087] ESC2 is made by adding a moisture scavenger to ESC1. It has similar melt index (I2), density, copolymerized VTMS content, and crystallinity at 23°C to ESC1 (because the moisture scavenger does not affect these properties). ESC2 is commercially available from The Dow Chemical Company in Midland, Michigan.

[0088] ESC3 is characterized by a melt index (I2) of 1.5 g / 10 minutes, a density of 0.921 g / cc, a copolymerized VTMS content of 0.31 mol%, and a crystallinity of 46.83 wt% at 23° C. ESC3 is commercially available from The Dow Chemical Company, Midland, Michigan.

[0089] ESC4, ESC5, ESC6, and ESC7 were prepared as follows: A mixture of ethylene, VTMS, and propylene used as a chain transfer agent was charged to a stirred autoclave reactor with a capacity of 545 milliliters (mL). An organic peroxide (a 75% by weight solution of t-butyl peroxyacetate in an aliphatic hydrocarbon) was added at a loading of 0.2% by weight based on the total weight of the ethylene, VTMS, propylene, and organic peroxide. The reactor was pressurized to 193 MPa and heated to 250° C. Ethylene, VTMS, and propylene were continuously fed into the reactor, and the prepared ESC was removed from the reactor. The ESC was converted into pellet form via melt extrusion. ESC4, ESC5, ESC6, and ESC7 were prepared under the effective process conditions shown in Table 1 and characterized by the properties shown in Table 2.

[0090] Table 1: Exemplary effective process conditions for preparing ESC4, ESC5, ESC6, and ESC7 .

[0091]

[0092]

[0093] Table 2: Characteristics of ESC4, ESC5, ESC6, and ESC7 .

[0094] Example No. ESC4 ESC5 ESC6 ESC7 <![CDATA[Melt Index (I2) (g / 10 min.)]]> 2.03 1.43 1.17 1.19 density 0.9220 0.9214 0.9211 0.9201 Vinyl groups per 1,000 carbon atoms (NMR) 0.135 0.143 0.164 0.168 Total VTMS content (wt%, by XRF) 4.15 2.92 2.44 1.58 Total VTMS content (mol%, calculated from weight %) 0.81 0.57 0.47 0.30 <![CDATA[M z(abs) / M w(abs) ]]> 18.66 16.28 16.08 17.44 <![CDATA[M w(conv) / M n(conv) ]]> 6.66 6.84 6.78 6.51 <![CDATA[((M z(abs) / M w(abs) ) / (M w(conv) / M n(conv) )]]> 2.80 2.38 2.37 2.68 Crystallinity at 23°C (wt%) 42.46 43.99 Not measured 45.55

[0095] ESC8 is made by adding a moisture scavenger to ESC3. It has similar melt index (I2), density, copolymerized VTMS content, and crystallinity at 23°C to ESC3 (because the moisture scavenger does not affect these properties). ESC8 is available from The Dow Chemical Company in Midland, Michigan.

[0096] Si-g-POE is a silane-grafted polyolefin elastomer characterized by a melt index (I2) of 21.9 g / 10 minutes and a grafted VTMS content of 0.75 mol%. It is prepared from an ethylene polymer (a copolymer of ethylene and 1-octene with 5.6 mol% octene comonomer content) and has a melt index (I2) of 30 g / 10 minutes, a density of 0.902 g / cc, and a crystallinity of 35.7 wt% at 23°C. The preparation of Si-g-POE is described as "Si-g-POE2" sample in World Intellectual Property Organization Publication No. WO / 2021 / 252312.

[0097] Si-g-LDPE is a silane-grafted low-density polyethylene characterized by a melt index (I2) of 1.9 g / 10 min and a grafted VTMS content of 0.57 mol%. It is prepared from a low-density polyethylene (LDPE) having a melt index (I2) of 8 g / 10 min, a density of 0.918 g / cc, and a crystallinity of 47.1 wt% at 23°C. The preparation of Si-g-LDPE is described in World Intellectual Property Organization Publication No. WO / 2021 / 252312 as a "Si-g-LDPE" sample.

[0098] CAT1 MB is a silanol condensation catalyst masterbatch developed for use with moisture-curable ethylene-silane copolymers (a blend of thermoplastic olefinic polymers, antioxidants, and approximately 2% by weight of dibutyltin dilaurate) and can be used with SI-LINK TM DFDB-5480NT is commercially available from The Dow Chemical Company, Midland, MI.

[0099] CAT2 MB is a silanol condensation catalyst masterbatch developed for use with moisture-curable ethylene-silane copolymers (a blend of thermoplastic olefinic polymers, antioxidants, and approximately 3% by weight of dibutyltin dilaurate) and can be SI-LINK TM DFDA-5481NT is commercially available from The Dow Chemical Company, Midland, Michigan.

[0100] OBC is an olefin block copolymer with a density of 0.877 g / cc and a melt index (I2) of 15 g / 10 min. TM9817 was commercially available from The Dow Chemical Company, Midland, Michigan.

[0101] The compatibilizer is maleic anhydride grafted ethylene vinyl acetate copolymer and can be FUSABOND TM C250 is commercially available from The Dow Chemical Company, Midland, MI.

[0102] The filler was magnesium hydroxide (HFFR) and is commercially available as FR-20-100 from Israel Chemicals Ltd., Tel Aviv-Yafo, Israel.

[0103] AO1 is a sterically hindered phenolic antioxidant with the chemical name of pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), which can be used in IRGANOX TM 1010 was commercially available from BASF, Ludwigshafen, Germany.

[0104] AO2 is distearyl thiodipropionate and can be NAUGARD TM DSTDP was commercially available from Addivant, Danbury, CT.

[0105] OBH is oxalylbis(benzylidene)hydrazide and is commercially available from Sigma-Aldrich, St. Louis, MO.

[0106] Silicone is DOWSIL TM Si powder resin modifier 4-7081 and is commercially available from The Dow Chemical Company, Midland, MI.

[0107] OTS is octyltriethoxysilane and can be PROSIL TM 9202 was commercially available from SiVance LLC, a Milliken & Co.

[0108] The carbon black was Vulcan XC72 and is commercially available from Cabot Corporation, Alpharetta, GA.

[0109] The carbon black-containing intermediate compound based on ESC1 consists of 70% by weight of ESC1 and 30% by weight of carbon black. Its preparation has been described previously (see CE6).

[0110] The carbon black-containing intermediate compound based on ESC3 consists of 70 wt% ESC3 and 30 wt% carbon black. Its preparation is described above (see CE7).

[0111] FR MB is a flame retardant masterbatch that is a blend of a thermoplastic olefinic polymer, an antioxidant, a hindered amine stabilizer, and 60 wt% filler (brominated flame retardant and antimony trioxide). FR MB is commercially available from The Dow Chemical Company, Midland, Michigan.

[0112] CB MB is a carbon black masterbatch comprising a blend of a thermoplastic olefinic polymer, an antioxidant, and about 40 wt.% carbon black (filler). CB MB is commercially available from The Dow Chemical Company, Midland, Michigan.

[0113] CA MB is a thermoplastic olefinic polymer comprising a thermoplastic olefinic polymer, an antioxidant and about 3 wt. % of an arylsulfonic acid (Brønsted acid ( CA MB is commercially available from The Dow Chemical Company, Midland, Michigan.

[0114] CC MB is a combined catalyst and carbon black masterbatch comprising a blend of a thermoplastic olefinic polymer, a moisture scavenger, an antioxidant, a stabilizer, about 31 wt% carbon black (filler), and about 1.5 wt% arylsulfonic acid (Brønsted acid). CC MB is commercially available from The Dow Chemical Company, Midland, Michigan.

[0115] HFFR masterbatch is a halogen-free flame retardant masterbatch formed by combining the materials in Table 3. TM HFFR MB was prepared by combining magnesium hydroxide and other ingredients with OBC in a mixer at a rotor speed of 40 revolutions per minute ("RPM") and a jacket (mixing bowl) temperature of 160°C. The OBC was fluxed for 5 minutes, and then the solid additives were added and mixed for an additional 10 minutes. Thereafter, the liquid additives for the HFFR MB were added and mixed for an additional 5 minutes. The HFFR MB mixture was removed and compression molded in a press to produce 75 mil (1.9 mm) plaques (120°C, 3.44 MPa, 5 minutes), cooled, and cut into small pieces ("flakes"). The flakes were fed to a Brabender 19.05 mm single screw extruder (25:1 L / D) operating at 40 RPM with a two-stage mixing screw (3:1 compression ratio) and a set temperature profile of 150°C / 160°C / 170°C / 180°C profile across all zones and head / die (using a 40 / 60 / 40 US mesh screen assembly) and made into strands which were in turn converted into pellets using a pelletizer. The pellets were packaged in sealed foil bags.

[0116] Table 3: Composition of HFFR MB

[0117]

[0118]

[0119] Sample Preparation and Results: IE1, IE2, and CE1

[0120] Wires were prepared using HFFR MB, a silanol condensation catalyst masterbatch (CAT1 MB) and an ethylene-silane copolymer (ESC). Prior to wire preparation, pellets of HFFR MB and CAT1 MB were dried in a vacuum oven at 60° C. for 48 hours or in a 70° C. oven for 16 hours to 24 hours to remove moisture. The wires were prepared by physically blending ESC pellets with pellets of HFFR MB and CAT1 MB in the specific proportions shown in Table 4. The physical blend was then melt-mixed during extrusion to prepare a wire structure on 10 American wire gauge (“AWG”) solid copper with a nominal wall thickness of 1.524 mm. The wire preparation unit included a BRABENDER TM 19.05mm variable speed drive extruder, 25:1L / D mixing screw, BRABENDER TM Crosshead drawing die, laboratory water cooling tank with air wipe, laser micrometer and variable speed wire puller. Wire samples were extruded at 40 RPM screw speed with a temperature profile of 140°C / 155°C / 165°C / 165°C (across zone 1, zone 2, zone 3 and head / die) and a 40 / 40 US mesh screen assembly.

[0121] The wires (coated conductors) were cured in a 90°C water bath for 72 hours to achieve final cure. After further conditioning for several hours at 23°C and 50% relative humidity, the properties of the cured coatings or coated conductors were tested.

[0122] Compared to CE1, IE1 and IE2 exhibit desirable lower hot creep values ​​(indicating increased crosslinking), enhanced flame retardancy (char length and FWCL values), and surprisingly improved tensile properties. The tensile properties results indicate that the compatibilization of the magnesium hydroxide filler is enhanced with increasing co-VTMS content in the ethylene-silane copolymer.

[0123] Table 4: Composition and characteristics of IE1 to IE2 and CE1 .

[0124]

[0125]

[0126] Sample Preparation and Results: IE3-IE6 and CE2-5

[0127] Wires were prepared using the HFFR MB, silanol condensation catalyst masterbatch (CAT1 MB) and ethylene-silane copolymer (ESC) or silane grafted polyolefin elastomer (Si-g-POE) or silane grafted low density polyethylene (Si-g-LDPE) of Table 3. Prior to wire preparation, pellets of HFFR MB and CAT1 MB were dried in a vacuum oven at 60°C for 48 hours or in a 70°C oven for 16 hours to 24 hours to remove moisture. Pellets of ESC, Si-g-POE or Si-g-LDPE were physically blended with pellets of HFFR MB and CAT1 MB in the specific proportions shown in Table 5. The blend was then melt mixed during extrusion to prepare wire construction on 10AWG solid copper with a nominal wall thickness of 1.524 mm. The wire preparation unit included a BRABENDER TM 19.05mm variable speed drive extruder, 25:1L / D mixing screw, BRABENDER TM Crosshead wire drawing die, laboratory water cooling tank with air wipe, laser micrometer and variable speed wire puller. Wire samples were extruded at a screw speed of 40 RPM with a temperature profile of 140°C / 155°C / 165°C / 165°C (across zone 1, zone 2, zone 3 and head / die) and a 40 / 40 US mesh screen assembly. The wire (coated conductor) was cured in a 90°C water bath for two or three days to achieve final cure. After further conditioning for several hours at 23°C and 50% relative humidity, the properties of the cured coating or coated conductor were tested.

[0128] Referring now to Table 5, IE3 through IE6 exhibit desirable lower hot creep values ​​(indicating increased crosslinking), similar flame retardant properties (char length and FWCL values), and surprisingly improved or similar tensile properties compared to CE2 and CE3. The tensile property results indicate that the compatibilization of the magnesium hydroxide filler is enhanced with increasing copolymerized VTMS content in the ethylene-silane copolymer.

[0129] CE4 does exhibit low thermal creep values ​​and good flame retardant and tensile properties. However, the Si-g-POE used in CE4 is not an ethylene-silane copolymer. Furthermore, the Si-g-POE is prepared from an ethylene polymer with a crystallinity of 36 wt% at 23°C. The lower crystallinity of the ethylene polymer used to prepare the Si-g-POE relative to the crystallinity of various ethylene-silane copolymers is undesirable for wear and pinch resistance, as flexibility or softness increases with decreasing crystallinity.

[0130] CE5 also produces a good balance of properties, however, the Si-g-LDPE used in CE5 is not an ethylene-silane copolymer and also has a crystallinity of 47 wt% at 23° C. The higher crystallinity of the ethylene polymer used to make the Si-g-LDPE relative to the crystallinity of the various ethylene-silane copolymers used in the examples of the present invention is undesirable because it excessively increases stiffness.

[0131] Table 5: Composition and characteristics of IE3 to IE6 and CE2 to CE5 .

[0132]

[0133] Sample Preparation and Results: CE6 and CE7

[0134] An intermediate compound containing carbon black based on ESC (ESC1 or ESC3) was prepared as follows: ESC was melt blended with carbon black as a filler (ESC / carbon black ratio of 70 / 30 wt %). A batch weighing approximately 283 grams was prepared using a Brabender mixer equipped with a Banbury blade and a 375 mL bowl volume with a rotor speed of 30 RPM and a set temperature of 150°C (by fluxing the ESC for 5 minutes, then adding the carbon black, and mixing for an additional 5 minutes). The melt-blended composition was removed from the mixing bowl and compression molded into a 75 mil (1.9 mm) thick plaque at 120°C by applying a pressure of 500 psi for 5 minutes. Two batches of each formulation were prepared, resulting in a total of approximately 500 grams, which were cut into strips using a guillotine knife and fed into a pelletizer (pelletizer) to prepare "flakes". Next, the "flakes" were introduced into a Brabender 19.05 mm extruder (25:1 L / D) operating at 40 RPM (using a 40 / 60 / 40 US mesh screen assembly) with a mixing screw (3:1 compression ratio) and a set temperature of 150°C across all zones and head / die and made into strands, which were in turn converted into pellets using a pelletizer. The pellets were packaged in sealed foil bags.

[0135] The intermediate compound containing carbon black based on ESC was melt blended with a silanol condensation catalyst masterbatch (CAT2 MB) in the ratio indicated in Table 6. The catalyst masterbatch was dried in a vacuum oven at 70°C for 16 to 24 hours and then packaged in a vacuum-sealed foil bag until use. Physical blends (in plastic bags) were prepared from pellets and catalyst masterbatch of the intermediate compound, which were then fed into a Brabender 19.05mm extruder equipped with a 25:1 Maddock screw to prepare a tape of approximately 60 mils (1.5mm) thickness. The set temperature distribution across the region was 160°C, 170°C, 180°C, and 185°C at the head / die. A 40 / 60 / 40US mesh screen assembly was used and the screw speed was 40RPM. The tape was cured in a 90°C water bath for 20 hours to achieve final curing. After further conditioning for several hours at 23°C and 50% relative humidity, the properties of the cured tapes were tested.

[0136] CE6 exhibits significantly poorer tensile elongation values ​​compared to CE7. That is, with carbon black as the sole filler in the composition, increasing the copolymerized VTMS content in the ethylene-silane copolymer results in poor tensile elongation (consistent with no significant compatibilization by this filler).

[0137] Table 6: Composition and characteristics of CE6 and CE7 .

[0138]

[0139] Sample preparation and results: CE8-CE13

[0140] CE8-CE13 were prepared by mixing pellets of the components of Table 7 in a fiber drum. Subsequently, the samples were melt mixed during extrusion to form wires on 14 AWG solid copper conductors to prepare coated conductors having a 0.762 mm thick coating of the polymer composition. A 63.5 mm Davis standard extruder with a twin-helix Maddock screw and 20 / 40 / 60 / 20 mesh screens was used to produce wires at the following set temperatures (° C.) across Zone 1 / Zone 2 / Zone 3 / Zone 4 / Zone 5 / Head / Die: 129.4 / 135.0 / 143.3 / 148.9 / 151.7 / 165.6 / 165.6. The length to diameter (L / D) ratio of the screw was 26 (measured from the start of the screw flight to the screw tip) or 24 (measured from the screw position corresponding to the end of the feed housing to the screw tip). Wire configurations were produced at a line speed of 91.44 m / min using the following screw speeds: 38 RPM for CE8 and CE9; 37 RPM for CE10 and CE11; and 39 RPM for CE12 and CE13. The wires (coated conductors) were cured at 23°C and 50% relative humidity (RH) for 3 to 7 weeks, followed by a 20-hour final cure in a 90°C water bath.

[0141] Comparing CE8 with CE9 and CE10 with CE11, increasing the copolymerized VTMS content in the ethylene-silane copolymer resulted in poorer tensile elongation. Specifically, since FR MB contains a halogenated flame retardant and antimony trioxide as fillers, and both CB MB and CC MB contain carbon black as fillers, increasing the copolymerized VTMS content in the ethylene-silane copolymer does not significantly increase the compatibilization of these fillers.

[0142] Comparing CE12 with CE13, both of which do not contain any filler, the increase in the copolymerized VTMS content in the ethylene-silane copolymer leads to poorer tensile elongation.

[0143] Table 7: Composition and characteristics of CE8 to CE13 .

[0144]

[0145] As demonstrated above, the polymer compositions of the present disclosure do not suffer a loss in tensile strain at break (or even exhibit an increased tensile strain at break) compared to polymer compositions using ethylene-silane copolymers having less than 0.4 mol% of the copolysilane, and achieve a hot creep of 175% or less after final cure as measured in accordance with UL 2556 Section 7.9 or ICEA-T-28-562-2003.

[0146] Comparing IE1 and IE2 with CE1, increasing the copolymerized VTMS content in the ethylene-silane copolymer unexpectedly leads to enhanced tensile strength and elongation when magnesium hydroxide is used as a filler (upon crosslinking—using the Lewis acid, dibutyltin dilaurate, as a silanol condensation catalyst). In contrast, the opposite effect on tensile elongation is observed when carbon black is used as a filler (see CE6 and CE7).

[0147] Comparing CE2 and CE3 with IE3 to IE6, which also employed magnesium hydroxide as a filler and dibutyltin dilaurate as a silanol condensation catalyst, improved or similar tensile properties were obtained regardless of the copolymerized VTMS content in the ethylene-silane copolymer used. These results are consistent with those of IE1 and IE2 relative to CE1 and indicate that the compatibilization of the magnesium hydroxide filler is enhanced with increasing copolymerized VTMS content in the ethylene-silane copolymer.

[0148] Although combinations of metal hydrate fillers with silane-grafted ethylene polymers (such as POE and LDPE used for CE4 and CE5) have been disclosed in the prior art, the effect of the grafted VTMS content on the tensile elongation values ​​varies depending on the type of ethylene polymer used, which means that the trends observed when using ethylene-silane copolymers (a completely different class of silane-functionalized polyethylenes) as moisture-curable resins are not as clear.

[0149] The use of halogenated flame retardants and antimony trioxide, as well as carbon black (as a filler) with ethylene-silane copolymers, also resulted in a deterioration in tensile elongation with increasing copolymerized VTMS content in the copolymers (CE8 to CE13). These findings are consistent with those when carbon black was used as the sole filler (CE6 and CE7), i.e., these fillers were not significantly compatibilized by the ethylene-silane copolymers.

Claims

1. A polymer composition comprising: an ethylene-silane copolymer comprising units derived from an ethylene monomer and a silane monomer, wherein the ethylene-silane copolymer has a copolymerized silane content of 0.40 mol% to 1.00 mol% based on the total molar amount of the ethylene-silane copolymer; Lewis acid catalysts; and A halogen-free flame retardant is selected from the group consisting of metal hydrates, silicon dioxide, and combinations thereof.

2. The polymer composition of claim 1 , wherein the Lewis acid catalyst is selected from the group consisting of dibutyltin dilaurate, dioctyltin dilaurate, aluminum chloride, titanium chloride, zinc chloride, dimethylhydroxytin oleate, dioctyltin maleate, di-n-butyltin maleate, dibutyltin diacetate, dibutyltin dioctoate, stannous acetate, stannous octoate, lead naphthenate, zinc octoate, and cobalt naphthenate, and combinations thereof.

3. The polymer composition according to one of claims 1 and 2, wherein the metal hydrate is selected from the group consisting of aluminum hydroxide, magnesium hydroxide, brucite, calcium hydroxide, zinc hydroxide, iron hydroxide, copper hydroxide, and combinations thereof. 4 . The polymer composition according to claim 1 , wherein the polymer composition comprises 10 to 80 wt % of the halogen-free flame retardant, based on the total weight of the polymer composition. 5 . The polymer composition according to claim 1 , wherein the polymer composition comprises 10 to 90 wt % of the ethylene-silane copolymer, based on the total weight of the polymer composition.

6. The polymer composition according to one of claims 1 to 5, wherein the polymer composition exhibits a filler to catalyst weight ratio of 75 to 1000.

7. The polymer composition according to one of claims 1 to 6, wherein the ethylene-silane copolymer exhibits a crystallinity at 23°C as measured according to the Crystallinity Test of 40 to 46 wt%. 8 . The polymer composition according to claim 1 , wherein the ethylene-silane copolymer has a copolymerized silane content of 0.45 mol % to 0.85 mol %.

9. The polymer composition of one of claims 1 to 8, wherein the polymer composition exhibits one or more of a hot creep after final cure as measured according to ICEA-T-28-562-2003 of 175% or less and a tensile strain at break as measured according to ASTM D638-14 of 20% or greater.

10. A coated conductor, comprising: conductors; and The polymer composition according to any one of claims 1 to 9.

11. The coated conductor of claim 10, wherein the polymer composition exhibits one or more of a hot creep after final cure as measured according to ICEA-T-28-562-2003 of 175% or less and a tensile strain at break as measured according to UL 2556, Section 3.5 of 20% or greater.

Images