Polymeric compositions comprising homoconjugated acid catalysts

Abstract

A polymeric composition includes a silane functionalized polyolefin and a catalyst comprising a homoconjugated acid.

Description

[0001] POLYMERIC COMPOSITIONS COMPRISING HOMOCONJUGATED ACID CATALYSTS

[0002] BACKGROUND

[0003] Field of the disclosure

[0004] The present disclosure relates to polymeric compositions, and more specifically, to polymeric compositions that comprise homoconjugated acid catalysts.

[0005] Introduction

[0006] Silane functionalized ethylene-based polymers are used in the formation of moisture- crosslinkable polymeric compositions. Such polymeric compositions are used to fabricate wires and cables including low-voltage cable constructions and may be utilized as either a jacket for the cable or as electrical insulation. The silane group may be grafted onto the ethylene-based polymer or copolymerized with ethylene to form the silane functionalized ethylene-based polymers. The silane facilitates crosslinking of the polymeric composition. The crosslinking of the polymeric composition is often referred to as “curing.” Such a curing is accomplished with the formation of siloxane bonds via hydrolysis and condensation reactions aided by moisture cure catalysts. In practice, curing takes place in a water or steam bath at elevated temperatures such that the water may penetrate the polymeric composition and react with the silane-functionalization in the presence of the moisture cure catalyst. An effective moisture catalyst is one that is sufficiently active in the presence of moisture to hydrolyze alkoxysilane to silanol, exhibits good hydrolysis activity, exhibits good condensation activity while remaining active to condensation after the hydrolysis to silanol, and is compatible with the polyolefin phase even in the presence of water vapor in order to crosslink the polyolefin.

[0007] The measure of a moisture cure catalyst is often its ability to cure the polymeric composition to a specific mechanical property within a set period of time. A polymeric composition is sufficiently cured if it exhibits a hot creep of 175% or less with four hours of curing. Hot creep is measured at a temperature of 150°C under a fixed stress (e.g., 0.2 MPa) by the test method described ahead, based on Insulated Cable Engineers Association (ICEA) standard for power cable insulation materials, ICEA-T-28-562-2003.

[0008] Traditional catalysts for moisture cure reactions include tin-based moisture catalysts. For the tin-based catalysts, the most used catalyst is Dibutyltin dilaurate (“DBTDL”). Such tin- based moisture catalysts are under enhanced regulatory scrutiny and alternatives with comparable performance and enhanced EH&S profile are desired. Others have attempted to create tin- free catalyst solutions. For example, United States Patent number 10,640,641 B2 discloses silanol condensation cure catalysts having a mixture of one or more metal amidine complexes and one or more amine carboxylate salts. Similarly, United States Patent number 10,030,084 B2 discloses the use of 2-ethylhexanoic acid as a condensation cure catalyst crosslinking polymeric systems including alkoxysilane.

[0009] Acids may undergo a process called homoconjugation. Homoconjugation is the process that occurs when an acid and its conjugate base form a hydrogen bond between one another. Homoconjugation may also be known as homoassociation. Homoconjugation increases the acidity of the underlying acid by stabilizing the conjugate bases thereby lowering the effective acid dissociation constant (pKa) of the acid. The pKa measurements are made on pure samples under idealized conditions as the effect of homoconjugation is reduced in aqueous solutions because water forms stronger hydrogen bonds to the conjugate base than does the acid. United States Patent number 11,136,436 B2 discloses the use of homoconjugated acids for condensation polymerization of hydroxy 1-terminated polydiorganosiloxanes in non-aqueous or water comprising system. For example, the ‘436 patent may include method steps of removing water.

[0010] In view of the foregoing, it would be surprising to discover a moisture cure catalyst comprising a homoconjugated acid that can achieve a cure sufficient to produce a hot creep of 175% or less after four hours of curing in a polymeric composition.

[0011] SUMMARY OF THE DISCLOSURE

[0012] The inventors of the present application have discovered a moisture cure catalyst comprising a homoconjugated acid that can achieve a cure sufficient to produce a hot creep of 175% or less after four hours of curing in a polymeric composition.

[0013] The invention is the result of discovering that despite the presence of water and other compounds in a formulated polymeric composition, homoconjugated acids can persist and function as moisture cure catalysts. Such a feature is surprising because despite the large amount of water present during curing, the acid of the catalyst appears to remain homoconjugated as demonstrated by the hot creep performance data.

[0014] According to a feature of the present disclosure, a polymeric composition, comprises a silane functionalized polyolefin and a catalyst comprising a homoconjugated acid. According to another feature of the present disclosure, the homoconjugated acid is in an ionic bond with a cation.

[0015] According to another feature of the present disclosure, the cation is selected from the group consisting of guanidines, 1,8-Bis(dimethylamino)naphthalene, pyridine, piperidine, morpholine, trialkylamine, dialkylamine, alkylamine, l,4-diazabicyclo[2.2.2]octane (DABCO).

[0016] According to another feature of the present disclosure, the catalyst consists essentially of the homoconjugated acid and the cation.

[0017] According to another feature of the present disclosure, the catalyst is free of a metal complex.

[0018] According to another feature of the present disclosure, a pKa of a conjugate acid of the homoconjugated acid is 3 to 16 as measured according to Potentiometric Titration.

[0019] According to another feature of the present disclosure, the homocongugated acid is an organic acid.

[0020] According to another feature of the present disclosure, the homocongugated acid is a carboxylic acid.

[0021] According to another feature of the present disclosure, the homoconjugated acid is selected from the group consisting of 2-ethylhexanoic acid, neodecanoic acid, naphthenic acid, a carboxylic acid comprising 8 or more carbons and combinations thereof.

[0022] According to another feature of the present disclosure, a coated conductor, comprises a conductor, and the polymeric composition.

[0023] DETAILED DESCRIPTION

[0024] 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.

[0025] All ranges include endpoints unless otherwise stated.

[0026] 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); EN refers to European Norm; DIN refers to Deutsches Institut fur Normung; and ISO refers to International Organization for Standards.

[0027] Polymeric Composition

[0028] The present disclosure is directed to a polymeric composition. The polymeric composition comprises a silane functionalized ethylene-based polymer and a catalyst comprising a homoconjugated acid. After moisture curing, the polymeric composition may exhibit a hot creep of 175% or less at 150°C after four hours of curing according to Hot Creep Testing. For example, the polymeric composition may exhibit a hot 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 after four hours of curing according to Hot Creep Testing.

[0029] Silane-Functionalized Polyole fin

[0030] A “silane-functionalized polyolefin” is a polymer that contains silane and equal to or greater than 50 wt %, or a majority amount, of polymerized a-olefin, based on the total weight of the silane-functionalized polyolefin. “Polymer” means a macromolecular compound prepared by reacting (i.e., polymerizing) monomers of the same or different type. As noted above, the polymeric composition comprises the silane-functionalized polyolefin. The polyolefin comprises polymerized a-olefins and optionally unsaturated esters.

[0031] The silane-functionalized polyolefin may include an a-olefin and silane copolymer (i.e., a-olefin / silane copolymer), a silane-grafted polyolefin, and / or combinations thereof. An “a- olefin and silane copolymer” is formed from the copolymerization of an a-olefin (such as ethylene) and a hydrolyzable silane monomer (such as a vinyl silane monomer) such that the hydrolyzable silane monomer is incorporated into the backbone of the polymer chain prior to the polymer's incorporation into the polymeric composition. A “silane-grafted polyolefin” or “Si-g-PO” may be formed by the Sioplas process in which a hydrolyzable silane monomer is grafted onto the backbone of a base polyolefin by a process such as extrusion, prior to the polymer's incorporation into the polymeric composition.

[0032] In examples where the silane-functionalized polyolefin is an a-olefin / silane copolymer, the silane-functionalized polyolefin is prepared by the copolymerization of at least one a-olefin and a hydrolyzable silane monomer. In examples where the silane-functionalized polyolefin is a silane grafted polyolefin, the silane-functionalized polyolefin is prepared by grafting one or more hydrolyzable silane monomers on to the a-olefin backbone. The silane-functionalized polyolefin comprises 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 98.5 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 of a-olefin and optional unsaturated ester based on a total weight of the silane functionalized polyolefin as measured using Fourier- Transform Infrared (FTIR) Spectroscopy. The a-olefin may include C2, or C3 to C4, or Ce, or Cs, or C10, or C12, or Ci6, or Cis, or C20 a-olefins, such as ethylene, propylene, 1-butene, 1- hexene, 4-methyl-l -pentene, and 1 -octene. The unsaturated ester can be an alkyl acrylate, alkyl methacrylate, or vinyl carboxylate.

[0033] The silane-functionalized polyolefin may comprise from 0.1 wt%, or 0.3 wt%, or 0.5 wt%, or 0.8 wt%, or 1.0 wt%, or 1.2 wt%, or 1.5 wt%, or 1.6 wt% to 1.8 wt%, or 2.0 wt%, or 2.3 wt%, or 2.5 wt%, or 3.0 wt%, or 3.5 wt%, or 4.0 wt%, or 4.5 wt%, while at the same time, 5.0 wt% or less, or 4.5 wt% or less, or 4.0 wt% or less, or 3.5 wt% or less, or 3.0 wt% or less, or 2.5 wt% or less, or 2.4 wt% or less, or 2.3 wt% or less, or 2.0 wt% or less, or 1.8 wt% or less, or 1.6 wt% or less, or 1 .4 wt% or less, or 1 .2 wt% or less, or 1.0 wt% or less, or 0.8 wt%, or 0.6 wt% or less of silane based on a total weight of the silane functionalized polyolefin as measured using FTIR Spectroscopy.

[0034] The silane-functionalized polyolefin has a density from 0.850 g / cc, or 0.860 g / cc, or 0.875 g / cc, or 0.880, or 0.890 g / cc to 0.900 g / cc, or 0.910 g / cc, or 0.915 g / cc, or 0.920 g / cc, or 0.930 g / cc, or 0.940 g / cc, or 0.950 g / cc or 0.960 g / cc, or 0.965 g / cc, while at the same time, 0.970 g / cc or less, or 0.960 g / cc or less, or 0.950 g / cc or less, or 0.940 g / cc or less, or 0.930 g / cc or less, or 0.920 g / cc or less, or 0.910 g / cc or less, or 0.900 g / cc or less, or 0.890 g / cc or less, or 0.880 g / cc or less, or 0.870 g / cc or less, or 0.860 g / cc or less as measured by ASTM D792.

[0035] The silane-functionalized polyolefin may have a melt index as measured according to ASTM D1238 under the conditions of 190°C / 2.16 kilogram (kg) weight and is reported in grams eluted per 10 minutes (g / 10 min). The melt index of the silane-functionalized polyolefin 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 at the same time, 50.0 g / 10 min or less, or 45.0 g / 10 min or less, or 40.0 g / 10 min or less, or 35.0 g / 10 min or less, or 30.0 g / 10 min or less, or 25.0 g / 10 min or less, or 20.0 g / 10 min or less, or 15.0 g / 10 min or less, or 10.0 g / 10 min or less, or 5.0 g / 10 min or less, or 4.5 g / 10 min or less, or 4.0 g / 10 min or less, or 3.5 g / 10 min or less, or 3.0 g / 10 min or less, or 2.5 g / 10 min or less, or 2.0 g / 10 min or less, or 1.5 g / 10 min or less, or 1.0 g / 10 min or less.

[0036] A “hydrolyzable silane monomer” is a silane-containing monomer that will effectively copolymerize with an a-olefin (e.g., ethylene) to form an a-olefin / silane copolymer (such as an ethylene / silane copolymer), or graft to an a-olefin polymer (i.e., a polyolefin) to form a Si- g-PO, thus enabling subsequent crosslinking of the silane-functionalized polyolefin. A representative, but not limiting, example of a hydrolyzable silane monomer has structure (I): Structure (I) in which R1is a hydrogen atom or 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 R2independently is a hydrolyzable organic group such as an alkoxy group having from 1 to 12 carbon atoms (e.g., methoxy, ethoxy, butoxy), an aryloxy group (e.g., phenoxy), an araloxy group (e.g., benzyloxy), an aliphatic acyloxy group having from 1 to 12 carbon atoms (e.g., formyloxy, acetyloxy, propanoyloxy), an amino or substituted amino group (e.g., alkylamino, arylamino), or a lower-alkyl group having 1 to 6 carbon atoms, with the proviso that not more than one of the three R2groups is an alkyl. The hydrolyzable silane monomer may be copolymerized with an a-olefin (such as ethylene) in a reactor, such as a high-pressure process to form an a-olefin-silane copolymer (“i.e., a reactor copolymer”). In examples where the a-olefin is ethylene, such a copolymer is referred to herein as an ethylenesilane copolymer. The hydrolyzable silane monomer may also be grafted to a polyolefin (such as a polyethylene) by the use of an organic peroxide, such as 2,5-bis(tert-butylperoxy)-2,5- dimethylhexane, to form a Si-g-PO or an in-situ Si-g-PO. The in-situ Si-g-PO is formed by a process such as the MONOSIL™ process, in which a hydrolyzable silane monomer is grafted onto the backbone of a polyolefin during the extrusion of the present composition to form a coated conductor, as described, for example, in USP 4,574,133.

[0037] The hydrolyzable silane monomer may include silane monomers that comprise an ethylenically unsaturated hydrocarbyl group, such as a vinyl, allyl, isopropenyl, butenyl, cyclohexenyl or gamma (meth)acryloxy allyl group, and a hydrolyzable group, such as, for example, a hydrocarbyloxy, hydrocarbonyloxy, or hydrocarbylamino group. Hydrolyzable groups may include methoxy, ethoxy, formyloxy, acetoxy, proprionyloxy, and alkyl or arylamino groups. In a specific example, the hydrolyzable silane monomer is an unsaturated alkoxy silane, which can be grafted onto the polyolefin or copolymerized in-reactor with an a- olefin (such as ethylene). Examples of hydrolyzable silane monomers include vinyltrimethoxysilane (VTMS), vinyltriethoxysilane (VTES), vinyltriacetoxysilane, and gamma-(meth)acryloxy propyl trimethoxy silane. In context to Structure (I), for VTMS: x = 0; R1= hydrogen; and R2= methoxy; for VTES: x = 0 R1= hydrogen; and R2= ethoxy; and for vinyltriacetoxysilane: x = 0; R1= H; and R2= acetoxy.

[0038] Examples of suitable ethylene-silane copolymers are commercially available as SI- LINK™ DFDA-5451 NT and SI-LINK™ AC DFDB-5451 NT, each available from The Dow Chemical Company, Midland, Mich.

[0039] The polymeric composition may comprise from 10 wt% to 99 wt% of the silane- functionalized polyolefin. For example, the polymeric composition comprises 10 wt% or greater, or 15 wt% or greater, or 20 wt% or greater, or 25 wt% or greater, or 30 wt% or greater, or 35 wt% or greater, or 40 wt% or greater, or 45 wt% or greater, or 50 wt% or greater, or 55 wt% or greater, or 60 wt% or greater, or 65 wt% or greater, or 70 wt% or greater, or 75 wt% or greater, or 80 wt% or greater, or 85 wt% or greater, or 90 wt% or greater, or 95 wt% or greater, or 98 wt% or greater, while at the same time, 99 wt% or less, or 95 wt% or less, or 93 wt% or less, or 90 wt% or less, 85 wt% or less, or 80 wt% or less, 75 wt% or less, or 70 wt% or less, 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 of the silane-functionalized polyolefin based on the total weight of the polymeric composition.

[0040] Ethylene-based polymer

[0041] The polyolefin of the silane functionalized polyolefin may be an ethylene-based polymer. Additionally, the ethylene-based polymer may not be silane functionalized and it may be used as a blend component in the formulation. The ethylene-based polymer may be a nonpolar or polar ethylene-based polymer. As used herein, the term “non-polar” when used in connection with a polymer means that it comprises 0.1 wt% or less of a polar monomer or comonomer as measured using Nuclear Magnetic Resonance (“NMR”) or Fourier-Transform Infrared (“FTIR”) Spectroscopy or X-ray Fluorescence (XRF) techniques. 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. Descriptions of “ethylene-based” polymers (both polar and non-polar) can be found in Patel, R., “Types and Basics of Polyethylene”, In: Mark A. Spalding and Ananda M. Chatteqee (eds.), Handbook of Industrial Polyethylene and Technology, Chapter 4. Scrivener, 2017. pp. 105-138. The polar ethylenebased polymer can include ethylene and one or more unsaturated ester (such as an alkyl acrylate, alkyl methacrylate, or vinyl carboxylate). The non-polar 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 polymer can have a unimodal or a multimodal molecular weight distribution and can 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 weights, 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. The term “multimodal” refers to polymers that are characterized by having at least two distinct peaks in a gel permeation chromatography (GPC) chromatogram depicting the molecular weight distribution of the composition. Accordingly, the generic term multimodal polymer includes bimodal polymers, which have two primary fractions: a first fraction, which may be a low molecular weight fraction and / or component, and a second fraction, which may be a high molecular weight fraction and / or component.

[0042] 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 98.5 wt% or greater, or 99 wt% or greater, or 99.5 wt% or greater, while at the same time, 100 wt% or less, or 99.5 wt% or less, or 99 wt% or less, or 98.5 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 based on the total weight of the ethylene-based polymer as measured using NMR or FTIR Spectroscopy or XRF. Other units of the ethylene-based polymer may include unsaturated ester (such as an alkyl acrylate, alkyl methacrylate, or vinyl carboxylate) or a-olefins (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-l -pentene, and 1 -octene).

[0043] The ethylene -based polymer may be a polar ethylene-based polymer. As used herein, the term “polar” when used in connection with a polymer means that it comprises 0.1 wt% or more of a polar monomer or comonomer as measured using NMR or FTIR Spectroscopy or XRF techniques. Units other than ethylene of the polar ethylene-based polymer may be derived from one or more polymerizable monomers including, but not limited to, acids and unsaturated esters. The acids may be acrylic acid and methacrylic acid. The unsaturated esters may be alkyl acrylates, alkyl methacrylates, or vinyl carboxylates. The alkyl groups can have from 1 to 8 carbon atoms, or from 1 to 4 carbon atoms. The carboxylate groups can have from 2 to 8 carbon atoms, or from 2 to 5 carbon atoms. Examples of acrylates and methacrylates include, but are not limited to, ethyl acrylate, methyl acrylate, methyl methacrylate, t-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 butanoate. The polar ethylene-based polymer typically has a high level of long chain branching.

[0044] Catalyst

[0045] The polymeric composition also comprises the catalyst. The catalyst may be a moisture cure catalyst meaning that the catalyst catalyzes silanol condensation and hydrolysis reactions in the presence of water. The catalyst comprises one or more homoconjugated acids. As explained above, homoconjugation is the process that occurs when an acid and its conjugate base form a hydrogen bond between one another thereby increasing the acidity of the underlying acid by stabilizing the conjugate bases. The homoconjugated acid may be a Brpnsted acid. A Brpnsted acid includes any acid which is a molecule or ion that is able to lose, or “donate’- a hydrogen cation (proton, H+).

[0046] The acid of the homocongugated acid may be a variety of different acids. For example, the acid may be an organic acid, a carboxylic acid, an alkylsulfonic acid, an arylsulfonic acid, an alkylarylsulfonic acid, or an arylalkylsulfonic acid, 2-ethylhexanoic acid, 3 -ethanehexanoic acid, 4-ethanehexanoic acid, 5-ethanehexanoic acid, 2-octenoic acid, 3-octenoic acid, 4- octenoic acid, 5-octenoic acid, neodecanoic acid, naphthenic acid, a carboxylic acid comprising 8 or more carbons, octanoic acid, benzene- 1 ,2-dicarboxylic acid, benzene- 1 ,3 -dicarboxylic acid, 2-methylheptanoic acid, 3-methylheptanoic acid, 4-methylheptanoic acid, 5- methylheptanoic acid, and combinations thereof.

[0047] The homocongugated acid of the catalyst may have a charge and therefore may be ionically bound with another ion. For example, the homocongugated acid may be in an ionic bond with a cation. The cation may be selected the group consisting of guanidines, 1,8- Bis(dimethylamino)naphthalene, pyridine, piperidine, morpholine, trialkylamine, dialkylamine, alkylamine, l,4-diazabicyclo[2.2.2]octane (DABCO). ApKa of a conjugate acid of the homoconjugated acid may be from 3 to 16 as measured according to Potentiometric Titration. For example, the pKa of the conjugate acid of the homoconjugated acid may be 3 or greater, or 4 or greater, or 5 or greater, or 6 or greater, or 7 or greater, or 8 or greater, or 9 or greater, or 10 or greater, or 11 or greater, or 12 or greater, or 13 or greater, or 14 or greater, or 15 or greater, while at the same time, 16 or less, or 15 or less, or 14 or less, or 13 or less, or 12 or less, or 11 or less, or 10 or less, or 9 or less, or 8 or less, or 7 or less, or 6 or less, or 5 or less, or 4 or less as measured according to Potentiometric Titration.

[0048] The catalyst may consist essentially of the homoconjugated acid and the cation. The catalyst may be free of a metal complex. As used herein, the phrase “free of a metal complex” means that the catalyst comprises 1 wt% or less of a metal complex based on the total weight of the catalyst. Exemplary metals of the metal complexes include tin, titanium, lead, nickel, chromium, copper, bismuth and the like. The catalyst may comprise 1 wt% or greater, or 10 wt% or greater, or 25 wt% or greater, or 50 wt% or greater, or 75 wt% or greater, or 90 wt% or greater, 99 wt% or greater, or 100 wt% of the homoconjugated acid based on the total weight of the catalyst.

[0049] The polymeric composition may comprise 0.001 wt% or greater, or 0. 1 wt% or greater, or 1 wt% or greater, or 2 wt% or greater, or 3 wt% or greater, or 4 wt% or greater, while at the same time, 5 wt% or less, or 4 wt% or less, or 3 wt% or less, or 2 wt% or less, or 1 wt% or less, or 0.1 wt% or less of the catalyst based on the total weight of the polymeric composition.

[0050] Additives

[0051] The polymeric composition may include one or more additives. Nonlimiting examples of suitable additives include antioxidants, colorants, carbon black, corrosion inhibitors, lubricants, ultraviolet (UV) absorbers or stabilizers, anti-blocking agents, flame-retardants, coupling agents, compatibilizers, plasticizers, fillers, processing aids, and combinations thereof.

[0052] The polymeric composition may include an antioxidant. Nonlimiting examples of suitable antioxidants include phenolic antioxidants, thio-based antioxidants, phosphate-based antioxidants, and hydrazine-based metal deactivators. Suitable phenolic antioxidants include high molecular weight hindered phenols, methyl-substituted phenol, phenols having substituents with primary or secondary carbonyls, and multifunctional phenols such as sulfur and phosphorous-containing phenol. Representative hindered phenols include 1,3,5-trimethyl- 2,4,6-tris-(3,5-di-tert-butyl-4-hydroxybenzyl)-benzene; pentaerythrityl 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-tertbutylphenol;6-(4-hydroxyphenoxy)-2,4-bis(n-octyl-thio)-l,3,5 triazine; di-n- octylthio)ethyl 3,5-di-tert-butyl-4-hydroxy-benzoate; and sorbitol hexa[3-(3,5-di-tert-butyl-4- hydroxy-phenyl)-propionate]. The polymeric composition may include pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), commercially available as Irganox™ 1010 from BASF A nonlimiting example of a suitable methyl-substituted phenol is isobutylidenebis(4,6-dimethylphenol). A nonlimiting example of a suitable hydrazine-based metal deactivator is oxalyl bis(benzylidiene hydrazide). The masterbatch may contain from 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% antioxidant, based on total weight of the masterbatch.

[0053] The polymeric composition may include a processing aid. Nonlimiting examples of suitable processing aids include oils, organic acids (such as stearic acid), and metal salts of organic acids (such as zinc stearate). In an embodiment, the composition contains from 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% processing aid, based on total weight of the masterbatch.

[0054] The polymeric composition may contain from 0 wt% or greater, or 0.001 wt% or greater, or 0.002 wt% or greater, or 0.005 wt% or greater, or 0.006 wt% or greater, or 0.008 wt% or greater, or 0.009 wt% or greater, or 0.01 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 1.0 wt% or greater, or 2.0 wt% or greater, or 3.0 wt% or greater, or 4.0 wt% or greater, or 5.0 wt% or greater, or 10.0 wt% or greater, or 15.0 wt% or greater, or 20.0 wt% or greater, or 30 wt% or greater, or 40 wt% or greater, or 50 wt% or greater additive, based on the total weight of the masterbatch.

[0055] Coated Conductor

[0056] The present disclosure also provides a coated conductor. The coated conductor includes a conductor and a coating on the conductor, the coating including the masterbatch. The polymeric composition is at least partially disposed around the conductor to produce the coated conductor. The conductor may comprise a conductive metal or an optically transparent structure.

[0057] The process for producing a coated conductor includes mixing and heating the masterbatch to at least the melting temperature of the polymeric components in an extruder 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.

[0058] The polymeric 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 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.

[0059] Examples

[0060] Materials

[0061] The following materials were used in the formation of the inventive examples (IE) and comparative examples (CE).

[0062] HCA1 is tetramethyl guanidine and homoconjugated ethyl hexanoic acid. HCA1 was prepared by adding 2.00 g of 1,1,3,3-tetramethylguanidine to a 20 mL scintillation vial. Ethyl hexanoic acid (5.01 g) was added dropwise and the mixture was vortexed until a clear homogenous fluid formed. The mixture was allowed to rest for 24 hours before using. The tetramethyl guanidine and ethyl hexanoic acid were obtained from Sigma Aldrich, St. Louis, MO.

[0063] HCA2 is tetramethyl guanidine and homoconjugated neodecanoic acid. HCA2 was prepared by adding 2.00 g of 1,1,3,3-tetramethylguanidine to a 20 mL scintillation vial. Neodecanoic acid (5.98 g) was added dropwise, and the mixture was vortexed until a clear homogenous fluid formed. The mixture was allowed to rest for 1 day before using. The neodecanoic acid was obtained from Sigma Aldrich, St. Louis, MO.

[0064] SiEP is an ethylene-silane copolymer having a density of 0.922 g / cc, a crystallinity at 23°C of 46.9 wt% and a melt index of 1.5 g / 10 min (190°C / 2.16 kg), an alkoxy silane content of 1.3 wt% to 1.7 wt%. and is commercially available as SI-LINK™ DFDA-5451 NT from The Dow Chemical Company, Midland, Michigan.

[0065] DBTDL is dibutyl tin dilaurate and is commercially available from Sigma- Aldrich, St. Louis, MO.

[0066] LLDPE is an ethylene-based polymer having a density of 0.92 g / cc as measured according to ASTMD D792 and a melt index of 0.65 g / 10 min as measured according to ASTM D1238 and is commercially available as DFH-2065 from the from The Dow Chemical Company, Midland, Michigan.

[0067] Test Methods

[0068] Silane Testing: Use x-ray fluorescence spectroscopy (“XRF”) to determine weight percent (wt%) of silicon atom (Si) content of, and then calculate silane comonomeric unit wt% in, test samples of the ethylene-silane copolymer. Using a Buehler SimpliMet 300 automatic mounting press that is preheated for 3 minutes at 115.6° C. (240 degrees Fahrenheit (° F.)), press a powdered form of test sample for 1 minute under 8.3 megapascals (MPa; 1,200 pounds per square inch (psi)) to form a plaque having a thickness of about 6 mm, and cool the plaque to 25° C. Analyze the Si atom content of the plaque by wavelength dispersive XRF using a wavelength dispersive X-ray fluorescence spectrometer from PANalytical Axios. Determine Si atom content by comparing its line intensity in the XRF spectrum to a calibration curve for Si atom content that is established using polymer standards of known Si atom concentrations as independently measured using Neutron Activation Analysis (NAA) or Inductively Coupled Plasma (1CP) methods. Use the XRF measured Si atom wt% value, and the molecular weight(s) of the at least one silane comonomer from which the hydrolyzable silyl groups were derived, to calculate hydrolyzable silyl group comonomeric unit wt% (i.e., wt% of the hydrolyzable silyl groups) in the ethylene-silane copolymer. For hydrolyzable silyl groups derived from vinyltrimethoxysilane (VTMS), use the VTMS molecular weight of 148.23 g / mol. To calculate hydrolyzable silyl group content of (wt% of hydrolyzable silyl group comonomeric units in) the ethylene-silane copolymer, use the XRF obtained Si atom wt% (“C”) and the following formula: p = C * (m / 28.086)(l / 10000ppmw), wherein * means multiplication, / means division, p is wt% hydrolyzable silyl groups in ethylene-silane copolymer, C is the Si atom amount (XFR) in weight parts per million (ppmw), m is the molecular weight in g / mol of the silane comonomer from which the hydrolysable silyl groups are derived, 28.086 is the atomic weight of a silicon atom, and 10000 ppmw is the number of weight parts per million in 1.00 wt%. For example, when XRF shows 379 ppmw of Si atom in ethylene-silane copolymer and the comonomer used to make the ethylene-silane copolymer is VTMS having a molecular weight of 148.23 g / mol, the wt% comonomeric content is 0.20 wt%. To calculate mol% of hydrolyzable silyl group comonomeric units in the ethylene-silane copolymer of the silane comonomer used, use the calculated wt% of the hydrolyzable silyl group comonomeric units in ethylene-silane copolymer and the following equation: G = 100 * (p / m) / [(p / m) + (100.00 wt% - p) / 28.05 g / mol], wherein * means multiplication, G is mole percent (mol%) of hydrolyzable silyl groups in the ethylene- silane copolymer; p is wt% of hydrolyzable silyl groups in ethylene-silane copolymer, m is 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 monomer ethylene (H2C=CH2). For example, when comonomeric 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 comonomeric content is 5.0 wt% and the comonomer is VTMS, p = 5.0 wt% and m = 148.23 g / mol, and G = 0.99 mol%. When two or more silane comonomers having different molecular weights are used to make ethylene-silane copolymer, the molecular weight used in the calculation of the total mol% of all hydrolyzable silyl groups in ethylene-silane copolymer is a weighted average molecular weight of the comonomers. The weighting may be determined by the proportion of the amounts of the comonomers fed into the reactor; alternatively by NMR spectroscopy on the ethylene-silane copolymer to determine the relative amounts of the different comonomeric units in the ethylene-silane copolymer when the respective hydrolyzable silyl groups are bonded to different types of carbon atoms (e.g., tertiary versus secondary carbon atoms); alternatively by Fourier Transform Infrared (FT-IR) spectroscopy calibrated to provide quantitation of the different types comonomers.

[0069] Hot Creep Testing: Hot creep is measured according to UL 2556, but modified for slab specimens. Samples were run in triplicate. Sample bars were removed from a curing water bath, dried, and allowed to cool. The samples were then marked with benchmarks 25 + / - 2.5 mm apart (perpendicular to pulling) with a Sharpie pen. Each specimen was completely at rest when marked. The thickness and width were measured to calculate cross-sectional area in mm2. A weight proportional to the cross-sectional area of sample was applied according to equation

[0070] (2):

[0071] Weight (g) = width (mm) * thickness (mm) * 20.4 g / mm2Eq. (2)

[0072] The weight included all components clamped on the bottom side of specimen and was within 2 g from calculated value. A weight clamp was placed approximately 10 mm from the benchmark. The sample and weight clamp were placed in a recirculating air oven set at 150°C for 15 minutes. At the end of the test, the benchmarks were measured in place without cooling or relaxing specimen. The hot creep elongation value was then calculated according to equation

[0073] (3):

[0074] Hot creep elongation [%] = 100*(Dfmai-Dmitiai) / Dinitiai Eq. (3) Oscillatory Shear Rheology Testing: Oscillatory shear rheology was measured on a TA DHR-3 rheometer with ETC environmental control oven and an 8 mm parallel plate geometry. Samples were tested after curing for 0, 2 and 4 hours. Testing was performed at 130°C under a nitrogen atmosphere. Discs were loaded and several Newtons (N) of normal force applied to achieve good contact before backing off to 0.5-1 N. A strain sweep was first performed at 1 rad / s to determine LVR strain range. Ultimately, all frequency sweeps were performed at 0.1% strain (within LVE). Frequency sweeps were collected between 100-0.025 rad / s. The value of the storage modulus (G’) at 0.025 rad / s was extracted for reporting and taken to be proportional to the crosslink density. The frequency value was chosen to emphasize the effect of covalent crosslinks and give a better dynamic range than at higher frequencies where entanglements and other effects have a large influence on G’.

[0075] Potentiometric Titration: In a potentiometric titration, a sample is titrated with acid or base using a pH electrode to monitor the course of titration. The pKa value is calculated from the change in shape of the titration curve compared with that of a blank titration, i.e. without a sample present.

[0076] Sample Preparation

[0077] To begin, the homoconjugated catalysts were compounded into a masterbatch before introduction into the ethylene-based polymer. Masterbatch compounding was performed on a Rheometer Services Inc. rs7500 drive unit with a Techmix 6 bowl with roller-type rotors. A nitrogen purge was used throughout when possible. The LLDPE was fluxed in the bowl at 130°C and at a rotor speed of 40 revolutions per minute. Once melted, a nitrogen purged line was placed in the headspace and the polymer allowed to flux for 2 additional minutes. Catalyst was added dropwise from a tared syringe, while maintaining nitrogen flow. Fluxing was continued for 2 minutes after the catalyst addition was complete. The masterbatch was quickly removed from the mixer and allow to cool in a canister under nitrogen flow before storing in a moisture proof bag with desiccant. Table 1 provides the amount of each catalyst and EEDPE used to form the masterbatches. Table 1

[0078] After the formation of the masterbatches, each was mixed with the SiEP. 13.0 g of SiEP was compounded with 0.68 g (5 wt%) of catalyst masterbatch (MB) in a 15 cc XPLORE™ microcompounder with nitrogen purge. The barrel of the microcompounder was first heated to 135°C and its speed was set to 40 revolutions per minute. Under recirculation, the SiEP was added as pellets via a plunger and allowed to flux for 2 minutes. The relevant masterbatch was then added via plunger and the polymeric composition was allowed to compound for another 4 minutes. The polymeric composition was then extruded. The relative mixtures of SiEP and masterbatch are provided in Table 2.

[0079] Table 2

[0080] A slab (7-8 g) was pressed in a heated carver press (75 x 75 mm chase) at 150°C. Bars for hot creep were punched using a 11 x 60 mm custom die on a clicker press prior to curing and discs for rheology were manually punched using an 8 mm steel die after curing. Specimens were placed in a temperature-controlled water bath with lid set at 90°C. Samples were removed at 2 hours for rheology testing. Finally, samples were removed at 4 hours for both hot creep and rheology testing.

[0081] Results

[0082] Table 3 provides the results of the hot creep and rheology testing on the inventive and comparative examples. Table 3

[0083] Referring now to Table 3, CE1 demonstrates that neodecanoic acid, in a nonhomoconjugated state, is incapable of sufficiently curing the polymeric composition as demonstrated by the fact it broke during hot creep testing. With respect to CE2, DBTDL is a well-known and used catalyst, so it is expected that it would adequately cure the polymeric composition. Referring now to IE1 and IE2, it can been seen that the homoconjugated catalysts demonstrate superior performance in the hot creep testing as compared to both CE1 and CE2. While the storage modulus of IE1 and IE2 are not as high as CE2 comprising DBTDL, both were greater than CE1 and IE2 achieved comparable storage modulus values with CE2.

Claims

CLAIMSWhat is claimed is1. A polymeric composition, comprising: a silane functionalized polyolefin; and a catalyst comprising a homoconjugated acid.

2. The polymeric composition of claim 1 , wherein the homoconjugated acid is in an ionic bond with a cation.

3. The polymeric composition of claim 2, wherein the cation is selected from the group consisting of guanidines, 1,8-Bis(dimethylamino)naphthalene, pyridine, piperidine, morpholine, trialkylamine, dialkylamine, alkylamine, l,4-diazabicyclo[2.2.2]octane (DABCO).

4. The polymeric composition of any one of claims 2 and 3, wherein the catalyst consists essentially of the homoconjugated acid and the cation.

5. The polymeric composition of any one of claims 1-4, wherein the catalyst is free of a metal complex.

6. The polymeric composition of any one of claims 1 -5 , wherein a pKa of a conjugate acid of the homoconjugated acid is 3 to 16 as measured according to Potentiometric Titration.

7. The polymeric composition of any one of claims 1-6, wherein the homocongugated acid is an organic acid.

8. The polymeric composition of any one of claims 1-7, wherein the homocongugated acid is a carboxylic acid.

9. The polymeric composition of any one of claims 1 -8, wherein the homoconjugated acid is selected from the group consisting of 2-ethylhexanoic acid, neodecanoic acid, naphthenic acid, a carboxylic acid comprising 8 or more carbons and combinations thereof.

10. A coated conductor, comprising: a conductor; and the polymeric composition of any one of claims 1-9.

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