Polyethylene composition for insulating layer

Abstract

The present disclosure relates to a composition. In one embodiment, the composition comprises (A) a base bimodal ethylene / C4-C8 alpha-olefin copolymer. The base bimodal ethylene / C4-C8 alpha-olefin copolymer has (i) a density of from 0.91 g / cc to 0.93 g / cc, (ii) an I21 / I2 of from 90 to 140, (iii) a Mw / Mn of from 7.0 to 15.0, (iv) a Mz of less than 600,000 g / mol, (v) an SHI ([eta] 0.1 / [eta] 100) value of from 5.0 to 30.0, (v) from 0 ppb to 80 ppb boron, and (vii) from 0 ppm to 5 ppm fluorine. The composition is suitable as an insulating layer on a cable.

Description

Background Art

[0001] Due to several favorable characteristics, linear low-density polyethylene (LLDPE) is widely used as a base resin for cable jacketing in telecommunications and power cables. LLDPE has a low dielectric constant, which provides good electrical insulation between conductive elements. LLDPE provides sufficient toughness for these applications and can be compounded with additives such as carbon black to achieve UV stability. It can also be formulated into semiconducting compounds. LLDPE is easily cross-linkable, which provides thermal stability over a wide temperature range beyond its thermoplastic state.

[0002] One disadvantage of LLDPE is that it typically has a narrow molecular weight distribution (MWD), with a polydispersity of less than 5.0, because it is metallocene-catalyzed in a single reactor. When LLDPE is extruded through an annular die at high shear rates, this narrow MWD results in a high degree of shear flow deformation, such as occurs in the production of the jacketing layer of wire or cable. When LLDPE is extruded onto cable at high rates, the high degree of shear flow deformation results in surface roughness of the cable jacket. Surface roughness of the cable jacket results in reduced electrical performance because the surface roughness concentrates the electric field in the cable jacket.

[0003] Chromium-catalyzed olefin polymerization is known to produce LLDPE with broad MWD characterized by high melt flow ratios, and in particular I of 80 or greater. 21 / I2 value. On the other hand, catalysts and activators typically used in solution phase polymerization systems (i.e., based on non-chromium catalysts) produce LLDPE with a narrow molecular weight distribution (polydispersity less than 5.0), which results in a rough surface during extrusion and can cause electrical stress concentrations and interface problems when the cable is jacketed. Furthermore, in wire and / or cable coating applications, LLDPE cable jackets require a smooth surface to maximize electrical performance and provide an aesthetically acceptable consumer end product. Therefore, the art recognizes the need for LLDPE with a broad MWD and high shear thinning (i.e., I 21 Polyethylene compositions, and in particular LLDPE compositions, having an I / I ratio greater than 80, are used for good processability at high extrusion shear rates to form smooth cable jackets for wire and / or cable coatings while providing a mechanically tough coating for cable protection. Summary of the Invention

[0004] The present disclosure relates to a composition. In one embodiment, the composition comprises (A) a base bimodal ethylene / C4-C8 α-olefin copolymer. The base bimodal ethylene / C4-C8 α-olefin copolymer has: (i) a density of 0.91 g / cc to 0.93 g / cc, (ii) an I of 90 to 140 21 / I2, (iii) Mw / Mn of 7.0 to 15.0, (iv) Mz of less than 600,000 g / mol, (v) SHI (η0.1 / η100) value of 5.0 to 30.0, (v) 0 ppb to 80 ppb boron, and (vii) 0 ppm to 5 ppm fluorine.

[0005] The present disclosure relates to a cable. In one embodiment, the cable comprises a conductor and a cable jacket disposed over the conductor. The cable jacket is comprised of a composition comprising: (A) a base bimodal ethylene / C4-C8 α-olefin copolymer having: (i) a density of 0.91 g / cc to 0.93 g / cc, (ii) an I 21 / I2, (iii) Mw / Mn of 7.0 to 15.0, (iv) Mz of less than 600,000 g / mol, (v) SHI (η0.1 / η100) value of 5.0 to 30.0, (vi) 0 ppb to 80 ppb boron, (vii) 0 ppm to 5 ppm fluorine. The cable jacket has a surface roughness Ra value of 5.0 μ-in to 25.0 μ-in. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 is a diagram showing the chemical structures of different types of carbon-carbon double bonds (unsaturated bonds in the polymer chain) of vinylene, trisubstituent, vinyl, and vinylene groups.

[0007] Figure 2 is a schematic representation of a flow diagram of a dual reactor polymerization system according to one embodiment of the present disclosure.

[0008] definition

[0009] Any reference to the Periodic Table of the Elements is to the Periodic Table as published by CRC Press, Inc., 1990-1991. Groups of elements in this table are referred to by a new notation for numbering the groups.

[0010] For purposes of U.S. patent practice, the contents of any referenced patent, patent application, or publication are incorporated by reference in their entirety (or their equivalent U.S. versions are incorporated by reference), particularly with respect to the disclosure of definitions (to the extent not inconsistent with any definitions specifically provided in this disclosure).

[0011] The numerical ranges disclosed herein include all values ​​from the lower limit to the upper limit, and include the lower limit and the upper limit. For ranges containing clear values ​​(e.g., 1 or 2, or 3 to 5, or 6, or 7), any subrange between any two clear values ​​is included (e.g., the above range 1 to 7 includes subranges of 1 to 2; 2 to 6; 5 to 7; 3 to 7; 5 to 6; etc.).

[0012] Unless stated to the contrary, implicit from the context, or customary in the art, all parts and percentages are by weight, and all test methods are current as of the filing date of this disclosure.

[0013] A "bimodal" polyethylene composition contains two polyethylene fractions that have been produced under different polymerization conditions, including differences in any process conditions and / or catalyst system, resulting in the fractions having different molecular weights and / or different comonomer contents. The first polyethylene fraction is a high molecular weight component. The second polyethylene fraction is a low molecular weight component. The bimodal polyethylene is an in-reactor blend of the high molecular weight component and the low molecular weight component, thereby producing one component that is then present in the production of the second component.

[0014] The term "blend" or "polymer blend" as used herein refers to a mixture of two or more polymers. A blend may be miscible or immiscible (not phase separated at the molecular level). A blend may or may not be phase separated. A blend may or may not include one or more domain configurations, as determined by transmission electron spectroscopy, light scattering, x-ray scattering, and other methods known in the art. A blend can be achieved by physically mixing the two or more polymers at a macroscopic level (e.g., melt blending resins or compounding) or a microscopic level (e.g., simultaneously formed in the same reactor).

[0015] The term "composition" refers to a mixture of materials comprising the composition, as well as reaction products and decomposition products formed from the materials of the composition.

[0016] The terms "comprising," "including," "having," and their derivatives are not intended to exclude the presence of any additional components, steps, or procedures, whether or not these are specifically disclosed. For the avoidance of any doubt, all compositions claimed through use of the term "comprising" may include any additional additives, adjuvants, or compounds, whether polymeric or otherwise, unless stated to the contrary. Conversely, the term "consisting essentially of excludes from the scope of any subsequently stated content any other components, steps, or procedures (except those that are not essential to operability). The term "consisting of excludes any component, step, or procedure not specifically recited or listed. Unless otherwise stated, the term "or" refers to the listed members individually and in any combination.

[0017] An "ethylene-based polymer" is a polymer that contains more than 50 mole percent (wt%) polymerized ethylene monomer (based on the total amount of polymerizable monomers) and optionally may contain at least one comonomer. Ethylene-based polymers include ethylene homopolymers and ethylene copolymers (meaning units derived from ethylene and one or more comonomers). The terms "ethylene-based polymer" and "polyethylene" are used interchangeably. Ethylene-based polymers may include ethylene homopolymers and ethylene copolymers (meaning units derived from ethylene and one or more comonomers). 12 α-olefin or C4-C8 α-olefin) copolymerized ethylene.

[0018] As used herein, the term "ethylene monomer" or "ethylene" refers to a chemical unit having two carbon atoms with a double bond therebetween, with each carbon bonded to two hydrogen atoms, wherein the chemical unit is polymerized with other such chemical units to form an ethylene polymer composition.

[0019] A "heteroatom" is an atom other than carbon or hydrogen. A heteroatom can be a non-carbon atom from Groups IV, V, VI, and VII of the periodic table. Non-limiting examples of heteroatoms include: F, N, O, P, B, S, and Si.

[0020] A "hydrocarbon" is a compound containing only hydrogen and carbon atoms. A hydrocarbon may have a linear structure, a cyclic structure, or a branched structure.

[0021] "Linear low density polyethylene" (or "LLDPE") is a linear ethylene / α-olefin copolymer containing a heterogeneous distribution of short chain branching, the copolymer comprising units derived from ethylene and units derived from at least one C3-C 10The LLDPE is characterized in that the long chain branching (if any) is minimal compared to conventional LDPE. The LLDPE has a density of 0.910 g / cc to 0.940 g / cc, or 0.910 g / cc to 0.930 g / cc, or 0.915 g / cc to 0.930 g / cc, or 0.915 g / cc to 0.925 g / cc.

[0022] "Low density polyethylene" (or "LDPE") is composed of ethylene homopolymer or ethylene copolymer with acrylate, vinyl acetate and / or vinyl silane as comonomers, having a density of 0.915 g / cc to 0.940 g / cc and containing long chain branching and a broad molecular weight distribution (MWD). LDPE is typically produced by high pressure free radical polymerization (tubular reactor or autoclave with a free radical initiator). Non-limiting examples of LDPE include PE from Chevron Phillips (MarFlex TM )、LyondellBasell(LUPOLEN TM ), Borealis, Ineos, ExxonMobil, etc.

[0023] An "olefin" is an unsaturated aliphatic hydrocarbon having a carbon-carbon double bond.

[0024] "Olefin-based polymers" (interchangeably referred to as "polyolefins") are polymers that contain a majority weight percent polymerized olefin monomer (based on the total amount of polymerizable monomers) and optionally may contain at least one comonomer. Non-limiting examples of olefin-based polymers include ethylene-based polymers and propylene-based polymers.

[0025] As used herein, the term "polymer" or "polymeric material" refers to a compound prepared by polymerizing monomers, whether of the same or different types, which, in polymerized form, provide the multiple and / or repeating "units" or "monomer units" that make up the polymer. Thus, the general term polymer encompasses the term homopolymer, which is commonly used to refer to polymers prepared from only one type of monomer, and the term copolymer, which is commonly used to refer to polymers prepared from at least two types of monomers. This general term also encompasses all forms of copolymers, such as random copolymers, block copolymers, etc. The terms "ethylene / α-olefin polymer" and "propylene / α-olefin polymer" refer to copolymers prepared by polymerizing ethylene or propylene, respectively, and one or more additional polymerizable α-olefin monomers, as described above. It should be noted that although polymers are often referred to as being "made from" one or more specified monomers, "based on" a specified monomer or monomer type, "containing" a specified monomer content, etc., in this context, the term "monomer" should be understood to refer to the polymerized residue of the specified monomer rather than the unpolymerized material. Generally speaking, polymers herein are referred to as being based on "units" that are the polymerized form of the corresponding monomer.

[0026] "Sheath" when used with respect to a cable includes insulating covering or layer, protective jacket, and the like.

[0027] A "wire" is a single strand of conductive metal (eg, copper or aluminum) or a single strand of optical fiber.

[0028] Test Method

[0029] 13 C NMR . 13 C NMR ( 13 C NMR) was used to determine the type and amount of short chain branching (i.e., comonomer) in the polymer. The C NMR was prepared by adding approximately 3 g of 1,1,2,2-tetrachloroethane (TCE) containing 25 wt% TCE-d2 and 0.025 M Cr(AcAc)3 to approximately 0.10 g of polymer sample in a 10 mm NMR tube. 13 C NMR samples. The samples were dissolved and homogenized by heating the tubes and their contents to 135°C using a heating block and vortex mixer. Each dissolved sample was visually inspected to ensure homogeneity. The samples were thoroughly mixed just before analysis and were not allowed to cool before being inserted into the heated NMR sample holder. All data were collected using a Bruker 600 MHz spectrometer equipped with a 10 mm high temperature freezer. Data were collected at a sample temperature of 120°C using a 7.8 second pulse repetition delay, a 90 degree flip angle, and inverse gated decoupling. 13 C data. All measurements were performed in locked mode on non-rotating samples. The samples were allowed to thermally equilibrate before data acquisition. 13C NMR chemical shifts were internally referenced to the EEE triplet at 30.0 ppm. Compositions were determined using assignments from Liu, W., Rinaldi, PL, McIntosh, LH, and Quirk, RP, Macromolecules, 34, 2001, 4757-4767 (for ethylene-co-octene polymers), and Sahoo, SK et al., Macromolecules 36, 2003, 4017-4028 (for ethylene-co-butene polymers), and the 13 The C NMR spectrum is integrated to solve the vector equation s=fM, where M is a distribution matrix, s is a row vector representation of the spectrum, and f is a mole fraction composition vector. The elements of f are considered to be triplets of E and O or B with all permutations of E and O (octene) or B (butene). The distribution matrix M is created with one row for each triplet in f and one column for each integrated NMR signal. The elements of the matrix are integral values ​​determined with reference to the distribution in (Liu, W., Rinaldi, PL, McIntosh, LH, and Quirk, RP, Macromolecules, 34, 2001, 4757-4767), or Sahoo, SK et al., Macromolecules 36, 2003, 4017-4028. This equation is solved by changing the elements of f as needed to minimize the integral of s and each sample. 13 The error function between the C data was performed using the Solver function in Microsoft Excel.

[0030] 1 H NMR . 1 H NMR ( 1 H NMR) is used to quantify the following types of carbon-carbon double bonds ("unsaturated bonds") in polymers. A "vinylene" is a carbon-carbon double bond having the formula R1-CH=CH-R2, where R1 and R2 are each one or more carbon atoms with attached hydrogen atoms. A "trisubstituent" is a carbon-carbon double bond where the double bond carbon is bonded to a total of three carbon atoms, and where R1, R2, and R3 (in Figure 1 ) are each a carbon atom. A "vinyl" is a carbon-carbon double bond of the formula R-CH=CH2, where R is a carbon atom. A "vinylene" is a carbon-carbon double bond of the formula R1(R2)C=CH2, where R1 and R2 are each one or more carbon atoms with attached hydrogen atoms. "Total unsaturation (or "total")" is the sum of the vinylene, trisubstituent, vinyl, and vinylene groups in the polymer. The chemical structures of vinylene, trisubstituent, vinyl, and vinylene groups are as follows: Figure 1Prepared by adding approximately 3 g of a 50 / 50 mixture of 1,1,2,2-tetrachloroethane (TCE-d2) and perchloroethylene (PCE) containing 0.001 M Cr(AcAc)3 to approximately 0.10 g of polymer sample in a 10 mm NMR tube. 1 H NMR spectra were performed on a Bruker 600 MHz spectrometer equipped with a 10 mm high temperature cryoprobe and a sample temperature of 120 °C. 1 H NMR. Two experiments were run to obtain the spectrum: a control spectrum for quantifying total polymer protons and a double presaturation experiment, which suppresses strong polymer backbone peaks and enables highly sensitive spectra for quantifying end groups. The control was run using a ZG pulse, 16 scans, an AQ of 1.64 s, and a D1 of 14 s. The double presaturation experiment was performed using a modified pulse sequence of 64 scans, an AQ of 1.64 s, a presaturation delay of 2 s, and a relaxation delay of 12 s.

[0031] density Measured according to ASTM D792, Method B. Results are reported in grams per cubic centimeter (g / cc).

[0032] Dynamic mechanical spectroscopy (DMS). DMS is used to measure polymer melt viscosity. Under 25,000 psi pressure, in air, at 350°F for five minutes, the resin is compression molded into a "3 mm thick × 1 inch" circular slab. The sample is then removed from the press and placed on a counter to cool. A constant temperature frequency sweep is performed under a nitrogen purge using a TA Instruments "Advanced Rheological Extension System (ARES)" equipped with 25 mm (diameter) parallel plates. The sample is placed on the plate and melted at 190°C for five minutes. The plates are then brought close to a gap of "2 mm", the sample is trimmed (extra sample extending beyond the periphery of the "25 mm diameter" plate is removed), and the test is then started. A five-minute delay is additionally built into the method to allow temperature equilibrium. The experiment is carried out at 190°C over a frequency range of 0.1 (radian / second) to 100 (radian / second). The strain amplitude is constant at 10%. From these data, the complex viscosity η*, tan(δ) or tan δ, the viscosity at 0.1 rad / s (V0.1), the viscosity at 100 rad / s (V100) and the viscosity ratio (V0.1 / V100) were calculated.

[0033] Measured in hours according to ASTM D1693 using Condition A or Condition B in solutions containing 10% IGEPAL CO-630 or 100% IGEPAL CO-630 Environmental stress crack resistance (ESCR)F0 and F50. ESCR F0 is the number of hours until the first sample cracks. ESCR F50 is the number of hours until half of the samples crack. IGEPAL CO-630 is nonylphenoxypoly(ethyleneoxy)ethanol.

[0034] Elemental analysis. Boron element analysis uses inductively coupled plasma-optical emission spectroscopy (ICP-OES) to determine. By weighing 0.25 grams (nominal) into a 15-mL Teflon test tube and adding 1 milliliter (mL) of deionized water, 2 mL of concentrated nitric acid, and 0.15 mL of hydrofluoric acid, the sample prepared for ICP metal analysis in duplicate. The tube is then placed in a Milestone Ultrawave closed container microwave digestion system and digested at 240°C for 30 minutes. After digestion, the sample is taken out from the microwave and diluted to a final volume of 10 milliliters using deionized water. The sample is transferred to an automatic sampler test tube and prepared for ICP-MS analysis.

[0035] Use Agilent 7900x (Agilent 7900x), use inductively coupled plasma mass spectrometry (ICP-MS) to analyze the solution of preparation.Use 0ng / mL, 0.5ng / mL, 1.0ng / mL, 5.0ng / mL and 10ng / mL calibration standards (SPEX CertiPrep, multi-element standard) prepared in 5% nitric acid and 1.5% hydrofluoric acid to calibrate instrument in the scope of 0ng / mL to 10ng / mL.The instrument operating conditions for this analysis are shown in Table A. Where possible, under no gas mode, hydrogen mode and helium mode, multiple isotopes of monitoring analyte.This is to carry out when there may have been any interference from sample matrix.

[0036] Table A. Agilent 7900x ICP-MS instrument operating conditions .

[0037]

[0038] All other elements were determined using neutron activation analysis ("NAA"). Duplicate samples were prepared by transferring approximately 3.5 g of resin into pre-cleaned 2 dram polyethylene vials. Duplicate fluorine standards were prepared from the NIST fluorine-benzoic acid standard into similar vials. The fluorine standard was diluted to 6 ml with 2-propanol and heat sealed. Similarly, Mg, Al, Ti, Hf, Cr, and Zr standards were prepared from their standard solutions (Certi.pure from SPEX) into 2 dram polyethylene vials. These were diluted to 6 ml with milli-Q pure water and the vials were heat sealed. The samples and standards were then analyzed for these elements using a Dow Mark ITRIGA nuclear reactor according to standard NAA procedure Global-SOP-01101.02. For Mg, Al, Ti, Hf, Cr, and Zr analysis, the samples were transferred to unirradiated vials prior to gamma spectroscopy. For fluorine, background contributions were accounted for by using clean vials and performing multiple runs with different vials. The reactions and experimental conditions for these elements are summarized in Table B. TM Element concentrations were calculated using software and standard comparison techniques.

[0039] Table B. Reactions and experimental conditions for some of the elements during the NAA

[0040]

[0041] Gel Permeation Chromatography. The average molecular weight and molecular weight distribution of ethylene-based polymers were determined using gel permeation chromatography (GPC). The chromatography system consisted of a PolymerChar GPC-IR (Valencia, Spain) high-temperature GPC chromatograph equipped with an internal IR5 infrared detector (IR5) and four capillary viscometers (DV) coupled to a Precision Detectors (now Agilent Technologies) 2-angle laser light scattering (LS) detector model 2040. For all absolute light scattering measurements, a 15-degree angle was used for measurement. The autosampler oven chamber was set to 160 degrees Celsius, and the column and detector chambers were set to 150 degrees Celsius. The columns used were four Agilent "MixedA" 30 cm 20-micron linear mixed-bed columns. The chromatographic solvent used was 1,2,4 trichlorobenzene containing 200 ppm of butylated hydroxytoluene (BHT). The solvent source was nitrogen sparged. The injection volume used was 200 μl and the flow rate was 1.0 ml / min.

[0042] The GPC column set was calibrated using 21 narrow molecular weight distribution polystyrene standards ranging in molecular weight from 580 to 8,400,000, arranged in a cocktail of 6 mixtures with at least ten times the molecular weight between the individual molecular weights. The standards were purchased from Agilent Technologies. For molecular weights equal to or greater than 1,000,000, 0.025 g of polystyrene standards were prepared in 50 ml of solvent, and for molecular weights less than 1,000,000, 0.05 g of polystyrene standards were prepared in 50 ml of solvent. The polystyrene standards were pre-dissolved at 80°C with gentle stirring for 30 minutes, then cooled, and the room temperature solutions were transferred to a 160°C autosampler dissolution oven to cool for 30 minutes. Polystyrene standard peak molecular weights were converted to polyethylene molecular weights using Equation 1 (as described in Williams and Ward, J. Polym. Sci., Polym. Let., 6, 621 (1968)):

[0043] M 聚乙烯 =a×(M 聚苯乙烯 ) B (Equation 1)

[0044] Wherein M is the molecular weight, A has a value of 0.43, and B equals 1.0.

[0045] A fifth-order polynomial was used to fit the calibration points to the corresponding polyethylene equivalents.

[0046] The total plate count for the GPC column set was performed using decane, which was introduced into the blank sample via a micropump controlled by the PolymerChar GPC-IR system. For four Agilent "Mixed A" 30 cm 20 micron linear mixed bed columns, the plate count of the chromatography system should be greater than 18,000.

[0047] The samples were prepared semi-automatically using the PolymerChar "Instrument Control" software, with a target sample weight of 2 mg / ml and solvent (containing 200 ppm BHT) added to a septum-capped vial previously sparged with nitrogen via a PolymerChar high-temperature autosampler. The samples were dissolved at 160 degrees Celsius for 2 hours with "low speed" shaking.

[0048] Based on the GPC results, using the internal IR5 detector (measurement channel) of the PolymerChar GPC-IR spectrometer, according to equations 2-4, the PolymerChar GPCOne TMThe software was used to calculate the Mn using the baseline-subtracted IR chromatogram at each equally spaced data collection point (i) and the polyethylene equivalent molecular weight obtained from the narrow standard calibration curve at point (i) according to Equation 1. (GPC) 、Mw (GPC) and Mz (GPC) Calculation.

[0049]

[0050] To monitor the deviation over time, a flow rate marker (decane) was introduced into each sample via a micropump controlled by the PolymerChar GPC-IR system. This flow rate marker (FM) was used to linearly correct the pump flow rate for each sample (Flow Rate (Nominal)) by comparing the RV of the corresponding decane peak in the sample (RV(FM Sample)) with the RV of the decane peak in the narrow standard calibration (RV(FM Calibrated)). Any change in the decane marker peak time was then assumed to be related to a linear change in flow rate (Flow Rate (Effective)) throughout the run. After calibrating the system based on the flow marker peak, the effective flow rate (relative to the narrow standard calibration) was calculated as Equation 5. TM The software completes the processing of the flow marker peaks.An acceptable flow rate correction is such that the effective flow rate should be within + / - 0.5% of the nominal flow rate.

[0051] Flow rate (effective) = flow rate (nominal) × (RV (FM calibration) / RV (FM sample)) (Equation 5)

[0052] Melt index As used herein, the term "melt index" or "MI" refers to a measure of the ease with which a thermoplastic polymer flows in the molten state. Melt index or "I2" is measured according to ASTM D1238, Method A, Condition 190°C / 2.16 kg, and is reported in grams eluted per 10 minutes (g / 10 min). "I 21 " Values ​​are measured according to ASTM D 1238 Method A, Condition 190°C / 21.6 kg and are reported as grams eluted per 10 minutes (g / 10 min). Melt flow rate is greater than "I 21 / I2" is determined by these individual values ​​by placing I 21 The melt flow rate ratio is calculated by dividing the value by the I2 value. 21The / I2 ratio is an indirect measure of the ratio of viscosities at high and low shear rates and indicates shear thinning behavior, which is related to both the molecular weight distribution (Mw / Mn) and the presence of long chain branches, each of which significantly affects processability. Generally speaking, polyethylene containing long chain branches possesses high melt strength and exhibits low viscosity under high shear rate conditions, allowing high processing rates compared to polyethylene with few or no long chain branches.

[0053] Shear Thinning Index (SHI) Calculated as the ratio of the dynamic viscosity measured at 0.1 rad / s to the dynamic viscosity measured at 100 rad / s and 190°C.

[0054] Surface roughness. The cable jacket surface roughness is evaluated by the average surface roughness Ra as measured using a Mitutoyo Surftest SJ-400 surface roughness tester. The results are reported in microinches or μ-in.

[0055] Tensile properties. The cable jacket of the present invention can be characterized by its tensile strength at break (in megapascals, MPa) and elongation at break (%). Stress at break and elongation at break are measured according to the ASTM D638 test procedure on compression molded specimens prepared according to ASTM D4703. Elongation at break ("TE") (Elongation at break or elongation to break) is the strain at break of the specimen, expressed as a percentage. Aged stress at break and aged elongation at break are each measured after holding the specimen at a temperature of 121° C. for 7 days, and the results are expressed in pounds per square inch (psi). DETAILED DESCRIPTION

[0056] The present disclosure provides a composition. In one embodiment, the composition comprises a bimodal ethylene / C4-C8 α-olefin copolymer. The base bimodal ethylene / C4-C8 α-olefin copolymer has one, some, or all of the following properties: (i) a density of 0.910 g / cc to 0.930 g / cc, (ii) an I of 90 to 140. 21 The base bimodal ethylene / C4-C8 α-olefin copolymer further comprises (vi) 0 ppb to 80 ppb boron, and (vii) 0 ppm to 5 ppm fluorine.

[0057] 1. Bimodal ethylene / C4-C8 α-olefin copolymer

[0058] The composition of the present invention comprises a bimodal ethylene / C4-C8 α-olefin copolymer. As used herein, "base bimodal ethylene / C4-C8 α-olefin copolymer" refers to the ethylene / C4-C8 α-olefin copolymer before the ethylene / C4-C8 α-olefin copolymer is blended or otherwise combined with a carbon black masterbatch.

[0059] The base ethylene / α-olefin copolymer is a bimodal ethylene / α-olefin copolymer. The α-olefin is C3-C 20 Comonomer or C4-C8 comonomer. Non-limiting examples of suitable α-olefin comonomers include butene, hexene, and octene. A "bimodal ethylene / α-olefin copolymer" is an ethylene / C4-C8 α-olefin copolymer having two different populations, which typically exhibit two peaks on the GPC curve. These distributions are observed statistically, that is, they are considered statistical distributions. Therefore, when there is one peak, the distribution has one mode and is unimodal. Two peaks are bimodal. Two or more peaks are multimodal. In one embodiment, the bimodal ethylene / C4-C8 α-olefin copolymer has a high molecular weight portion and a low molecular weight portion, thereby defining a "bimodal molecular weight distribution." The "high molecular weight portion" of the bimodal ethylene / α-olefin copolymer has an Mw of 100,000 g / mol to 1,000,000 g / mol, and the "low molecular weight portion" of the bimodal ethylene / α-olefin copolymer has an Mw of 1,000 g / mol to less than 100,000 g / mol. The bimodal ethylene / α-olefin copolymer has an Mw / Mn of 7.0 to 15.0, or 7.0 to 13.0, or 7.1 to 12.0. In one embodiment, the bimodal ethylene / C4-C8 α-olefin is an ethylene / octene copolymer.

[0060] In one embodiment, the base bimodal ethylene / C4-C8 alpha-olefin copolymer is produced in a solution polymerization process. "Solution polymerization process" refers to one or more continuous solution polymerization reactors operated under polymerization conditions wherein a polymer (e.g., polyethylene) is formed in a liquid polymerization solvent to which monomer (e.g., ethylene) and comonomer (e.g., C3-C8 alpha-olefin) are added. 20 α-olefins or C4-C8 α-olefins) and catalysts / cocatalysts (activators). As used herein, the term "polymerization conditions" refers to the process parameters for copolymerizing ethylene and comonomers in the presence of a catalyst system. Polymerization conditions include, for example, polymerization reactor conditions (reactor type), reactor pressure, reactor temperature, concentrations of reagents and polymers, solvents, supports, residence time and distribution, thereby affecting molecular weight distribution and polymer structure.

[0061] In one embodiment, the base bimodal ethylene / α-olefin copolymer is produced in a dual reactor solution polymerization system whereby the effluent from the first solution polymerization reactor flows into the second solution polymerization reactor. A first catalyst and a cocatalyst (or a first activator) are injected into the first solution polymerization reactor, and a second catalyst and a cocatalyst (or a second activator) are injected into the second solution polymerization reactor. Each of the first catalyst and the second catalyst does not contain or otherwise excludes chromium. Each of the first cocatalyst and the second cocatalyst does not contain or otherwise excludes boron and fluorine.

[0062] In one embodiment, a dual reactor solution polymerization system is used to produce a base bimodal ethylene / α-olefin copolymer that is an ethylene / C4-C8 α-olefin copolymer or an ethylene / octene copolymer having one, some, or all of the following properties:

[0063] (i) a density of 0.910 g / cc to 0.930 g / cc, or 0.915 g / cc to 0.925 g / cc; and / or

[0064] (ii) I of 90 to 140, or 92 to 135, or 93 to 130 21 / I2 ratio; and / or

[0065] (iii) an Mw / Mn of 7.0 to 15.0, or 7.0 to 13.0, or 7.1 to 12.0; and / or

[0066] (iv) an Mz of less than 600,000 g / mol, or from 100,000 g / mol to 500,000 g / mol, or from 200,000 g / mol to 400,000 g / mol, or from 300,000 g / mol to 400,000 g / mol; and / or

[0067] (v) an SHI value (η0.1 / η100) of 5.0 to 30.0, or 7.0 to 28, or 8.0 to 27, or 9.0 to 23.0; and / or

[0068] (vi) 0 parts per billion (ppb), or from greater than 0 ppb to 80 ppb, or from 1 ppb to 50 ppb boron;

[0069] (vii) 0 parts per million (ppm), or from greater than 0 ppm to 5 ppm, or from 1 ppm to 3 ppm fluorine; and / or

[0070] (viii) 0 ppb, or greater than 0 ppb to less than 100 ppb chromium; and / or

[0071] (ix) an I value of from 0.6 g / 10 min to 1.2 g / 10 min, or from 0.7 g / 10 min to 1.1 g / 10 min (hereinafter referred to as Composition 1); in one embodiment, Composition 1, when formed into a 75 mil tensile bar, has:

[0072] (1) Aged rupture stress of 2100 psi to 2900 psi, and / or

[0073] (2) Aged elongation at break of 500% to 700%, or 525% to 680%.

[0074] 2. Carbon black

[0075] In one embodiment, the composition comprises carbon black. The carbon black may or may not be a component of a carbon black masterbatch. When present, the carbon black masterbatch is composed of carbon black and a polyethylene carrier. Suitable polyethylene carriers include LDPE, LLDPE, and combinations thereof. Non-limiting examples of suitable carbon black masterbatches are AXELERON TM GP A-0037BK CPD, the AXELERON TM GP A-0037BK CPD contains carbon black P type or carbon C in LLDPE carrier.

[0076] In one embodiment, the composition contains 3.0 wt% to 10.0 wt%, or 4.0 wt% to 8.0 wt%, or 5.0 wt% to 7.0 wt%, or 5.78 wt% carbon black masterbatch, based on the total weight of the polyethylene composition, and / or 1.3 wt% to 4.5 wt%, or 1.8 wt% to 3.6 wt%, or 2.25 wt% to 3.15 wt%, or 2.6 wt% carbon black, based on the total weight of the polyethylene composition.

[0077] In one embodiment, the carbon black masterbatch is melt blended with the base bimodal ethylene / C4-C8 alpha-olefin copolymer. The melt blending can be performed by batch melt blending (e.g., by a Banbury mixer) or can be performed by continuous melt blending (e.g., by an extruder).

[0078] In one embodiment, the composition comprises

[0079] (A) 90 wt% to 97 wt%, or 92 wt% to 96 wt%, or 93 wt% to 95 wt% of a base bimodal ethylene / C4-C8 α-olefin copolymer, the base bimodal ethylene

[0080] The C4-C8 α-olefin copolymer has one, some or all of the following properties before blending with carbon black:

[0081] (i) a density of 0.910 g / cc to 0.930 g / cc, or 0.915 g / cc to 0.925 g / cc; and

[0082] / or

[0083] (ii) I of 90 to 140, or 92 to 135, or 93 to 130 21 / I2 ratio; and / or

[0084] (iii) an Mw / Mn of 7.0 to 15.0, or 7.0 to 13.0, or 7.1 to 12.0; and / or

[0085] (iv) an Mz of less than 600,000 g / mol, or from 100,000 g / mol to 500,000 g / mol, or from 200,000 g / mol to 400,000 g / mol, or from 300,000 g / mol to 400,000 g / mol; and / or

[0086] (v) an SHI value (η0.1 / η100) of 5.0 to 30.0, or 7.0 to 28, or 8.0 to 27, or 9.0 to 23.0; and / or

[0087] (vi) 0 parts per billion (ppb), or from greater than 0 ppb to 80 ppb, or from 1 ppb to 50 ppb boron;

[0088] (vii) 0 parts per million (ppm), or from greater than 0 ppm to 5 ppm, or from 1 ppm to 3 ppm fluorine; and / or

[0089] (viii) 0 ppb, or greater than 0 ppb to less than 100 ppb chromium; and / or

[0090] (ix) an I2 value of 0.6 g / 10 min to 1.2 g / 10 min, or 0.7 g / 10 min to 1.1 g / 10 min; and

[0091] (B) 1.3 wt% to 4.5 wt%, or 1.8 wt% to 3.6 wt%, or 2.25 wt%

[0092] % or 2.6 wt % of carbon black, the weight percentage of carbon black being based on the total weight of the composition (hereinafter referred to as Composition 2).

[0093] Composition can comprise one or more optional additives.When existing, the non-limiting example of suitable additive comprises antioxidant, tinting agent, corrosion inhibitor, lubricant, moisture curing catalyst, ultraviolet (UV) absorber or stabilizer, anti-caking agent, coupling agent, compatibilizer, plasticizer, filler, processing aid and their combination.When existing, the amount of additive is 0.05 % by weight to 5.0 % by weight of polyethylene composition, or 0.1 % by weight to 1.0 % by weight, or 0.1 % by weight to 0.5 % by weight, wherein % by weight is based on the gross weight of polyethylene composition.

[0094] In one embodiment, the composition comprises

[0095] (A) 90 wt% to 97 wt%, or 92 wt% to 96 wt%, or 93 wt% to 95 wt% of a base bimodal ethylene / C4-C8 α-olefin copolymer, the base bimodal ethylene

[0096] The C4-C8 α-olefin copolymer has one, some or all of the following properties before blending with carbon black:

[0097] (i) a density of 0.910 g / cc to 0.930 g / cc, or 0.915 g / cc to 0.925 g / cc; and

[0098] / or

[0099] (ii) I of 90 to 140, or 92 to 135, or 93 to 130 21 / I2 ratio; and / or

[0100] (iii) an Mw / Mn of 7.0 to 15.0, or 7.0 to 13.0, or 7.1 to 12.0; and / or

[0101] (iv) an Mz of less than 600,000 g / mol, or from 100,000 g / mol to 500,000 g / mol, or from 200,000 g / mol to 400,000 g / mol, or from 300,000 g / mol to 400,000 g / mol; and / or

[0102] (v) an SHI value (η0.1 / η100) of 5.0 to 30.0, or 7.0 to 28, or 8.0 to 27, or 9.0 to 23.0; and / or

[0103] (vi) 0 parts per billion (ppb), or from greater than 0 ppb to 80 ppb, or from 1 ppb to 50 ppb boron; and / or

[0104] (vii) 0 parts per million (ppm), or from greater than 0 ppm to 5 ppm, or from 1 ppm to 3 ppm fluorine; and / or

[0105] (viii) 0 ppb, or greater than 0 ppb to less than 100 ppb chromium; and / or

[0106] (ix) an I2 value of 0.6 g / 10 min to 1.2 g / 10 min, or 0.7 g / 10 min to 1.1 g / 10 min;

[0107] (B) 1.3 wt% to 4.5 wt%, or 1.8 wt% to 3.6 wt%, or 2.25 wt% to 3.15 wt%, or 2.6 wt% carbon black;

[0108] (C) 0.01 to 0.1 wt. % of a sulfur-containing antioxidant (such as, for example, IRGANOX 1035); and / or

[0109] (D) 0.1 to 0.9 wt% of an amine-containing antioxidant (such as, for example, NAUGARD SuperQ); and / or

[0110] (E) 0.01 to 0.9 wt % of a fluorine processing aid (such as, for example, DYNAMAR FX 5912), the component weight percentages being based on the total weight of the composition (hereinafter referred to as Composition 3).

[0111] In one embodiment, the carbon black of composition 3 comes from a carbon black masterbatch, and the composition comprises 1.7 wt% to 5.5 wt% of a second polyethylene (carrier resin of the carbon masterbatch) based on the total weight of composition 3. The second polyethylene is LLDPE, LDPE, and combinations thereof.

[0112] 3. Cable

[0113] The present disclosure provides a cable. In one embodiment, the cable comprises (i) a conductor and (ii) a cable jacket disposed over the conductor. The cable jacket may be an inner layer (non-surface layer) of the cable, or the cable jacket may be the outermost layer (surface layer) of the cable. The "outermost layer" is a layer having an outer surface that is exposed or significantly exposed to the surrounding environment.

[0114] As used herein, a "conductor" is one or more wires or fibers used to conduct heat, light, and / or electricity. The conductor can be a single wire / fiber or multiple wires / fibers and can be in stranded or tubular form. Non-limiting examples of suitable conductors include metals such as silver, gold, copper, carbon, and aluminum. The conductor can also be an optical fiber made of glass or plastic.

[0115] As used herein, a "cable" is at least one wire or optical fiber within a sheath, such as a cable jacket or protective outer sheath. Typically, a cable is two or more wires or two or more optical fibers bundled together, typically in a common cable jacket or covering and / or protective sheath. The individual wires or fibers within the sheath may be bare, covered, or insulated. A combination cable may contain both wires and optical fibers. Cables may be designed for telecommunications applications. Cables may be designed for low voltage, medium voltage, and / or high voltage applications. AC cables may be prepared according to the present disclosure, which may be low voltage, medium voltage, high voltage, or ultra-high voltage cables. Further, DC cables may be prepared according to the present disclosure, which may include high voltage or ultra-high voltage cables. Insulated electric conductors typically include a conductive core covered by a cable jacket. The conductive core may be solid or braided (e.g., a bundle of wires). Some insulated electric conductors may also contain one or more additional elements, such as one (or more) semiconductor layers and / or protective covers (e.g., coiled wires, tape, or sheaths). Examples are coated metallic wires and power cables, including those used for low voltage ("LV", 0 kilovolt (kV) to <5 kilovolt (kV) power distribution / transmission applications), medium voltage ("MV", 5kV to <69kV), high voltage ("HV", 69kV to 230kV), and extra high voltage ("EHV", >230kV). Power cable evaluations can use AEIC / ICEA standards and / or IEC test methods.

[0116] In one embodiment, the coated conductor is selected from the group consisting of fiber optic cables, communication cables (such as telephone cables or local area network (LAN) cables), power cables, wiring for consumer electronic devices, power charging cords for cellular phones and / or computers, computer data cables, power cords, appliance wiring materials, interior house wiring materials, consumer electronic accessory cords, and any combination thereof.

[0117] The cable comprises a conductor and a cable jacket positioned on or otherwise surrounding the conductor. The cable jacket comprises a composition (as previously disclosed herein) consisting of: (A) a base bimodal ethylene / C4-C8 alpha-olefin copolymer and optionally (B) carbon black with optional additives. In one embodiment, the cable jacket (consisting of the inventive composition) is in direct contact with the conductor. The term "direct contact" refers to a layer configuration in which the cable jacket is positioned adjacent to the conductor and there is no intermediate layer or intermediate structure between the conductor and the cable jacket. Alternatively, the cable jacket is in direct contact with the conductor.

[0118] In one embodiment, the cable comprises a conductor and a cable jacket disposed over the conductor. The cable jacket comprises a composition consisting of:

[0119] (A) Bimodal ethylene as the basis for ethylene / C4-C8 α-olefin copolymers or ethylene / octene copolymers

[0120] / α-olefin copolymer, the base bimodal ethylene / α-olefin copolymer has one, some or all of the following properties:

[0121] (i) a density of 0.910 g / cc to 0.930 g / cc, or 0.915 g / cc to 0.925 g / cc; and

[0122] / or

[0123] (ii) I of 90 to 140, or 92 to 135, or 93 to 130 21 / I2 ratio; and / or

[0124] (iii) an Mw / Mn of 7.0 to 15.0, or 7.0 to 13.0, or 7.1 to 12.0; and / or

[0125] (iv) an Mz of less than 600,000 g / mol, or from 100,000 g / mol to 500,000 g / mol, or from 200,000 g / mol to 400,000 g / mol, or from 300,000 g / mol to 400,000 g / mol; and / or

[0126] (v) an SHI value (η0.1 / η100) of 5.0 to 30.0, or 7.0 to 28, or 8.0 to 27, or 9.0 to 23.0; and / or

[0127] (vi) 0 parts per billion (ppb), or from greater than 0 ppb to 80 ppb, or from 1 ppb to 50 ppb boron;

[0128] (vii) 0 parts per million (ppm), or from greater than 0 ppm to 5 ppm, or from 1 ppm to 3 ppm fluorine; and / or

[0129] (viii) 0 ppb, or greater than 0 ppb to less than 100 ppb chromium; and / or

[0130] (ix) an I2 value of 0.6 g / 10 min to 1.2 g / 10 min, or 0.7 g / 10 min to 1.1 g / 10 min

[0131] (Composition 1); The cable sheath has:

[0132] (1) Aged rupture stress of 2100 psi to 2900 psi, and / or

[0133] (2) 500% to 700%, or 525% to 680% of the aged elongation at break, and / or

[0134] (3) Surface roughness Ra value of 5.0 μ-in to 25 μ-in, or 10.0 μ-in to 25 μ-in, or 8.0 μ-in to 24 μ-in. In another embodiment, the cable jacket is an inner layer.

[0135] In one embodiment, a carbon black masterbatch and additives are pre-compounded into an LLDPE resin using a Banbury mixer to completely disperse the carbon black and additives and produce homogeneous pellets composed of the carbon black masterbatch, additives, and LLDPE resin ("pre-compounded pellets"). Pellets of the base bimodal ethylene / C4-C8 α-olefin copolymer are introduced into an extruder for extrusion onto wire (wire extrusion). The pre-compounded pellets are fed directly into the extruder (hereinafter referred to as "BK").

[0136] In one embodiment, pellets of the base bimodal ethylene / C4-C8 α-olefin copolymer are introduced into an extruder for extrusion onto wire (wire extrusion). Additives are delivered directly into the extruder via carbon black masterbatch pellets (hereinafter referred to as "in-line").

[0137] In one embodiment, the cable comprises a conductor and a cable jacket disposed over the conductor. The cable jacket comprises a composition consisting of:

[0138] (A) 90 wt% to 97 wt%, or 92 wt% to 96 wt%, or 93 wt% to 95 wt% of a base bimodal ethylene / C4-C8 α-olefin copolymer having one of the following properties before blending with carbon black:

[0139] Some or all of:

[0140] (i) a density of 0.910 g / cc to 0.930 g / cc, or 0.915 g / cc to 0.925 g / cc; and

[0141] / or

[0142] (ii) I of 90 to 140, or 92 to 135, or 93 to 130 21 / I2 ratio; and / or

[0143] (iii) an Mw / Mn of 7.0 to 15.0, or 7.0 to 13.0, or 7.1 to 12.0; and / or

[0144] (iv) an Mz of less than 600,000 g / mol, or from 100,000 g / mol to 500,000 g / mol, or from 200,000 g / mol to 400,000 g / mol, or from 300,000 g / mol to 400,000 g / mol; and / or

[0145] (v) an SHI value (η0.1 / η100) of 5.0 to 30.0, or 7.0 to 28, or 8.0 to 27, or 9.0 to 23.0; and / or

[0146] (vi) 0 parts per billion (ppb), or from greater than 0 ppb to 80 ppb, or from 1 ppb to 50 ppb boron;

[0147] (vii) 0 parts per million (ppm), or from greater than 0 ppm to 5 ppm, or from 1 ppm to 3 ppm fluorine; and / or

[0148] (viii) 0 ppb, or greater than 0 ppb to less than 100 ppb chromium; and / or

[0149] (ix) an I2 value of 0.6 g / 10 min to 1.2 g / 10 min, or 0.7 g / 10 min to 1.1 g / 10 min;

[0150] (B) 1.3 wt% to 4.5 wt%, or 1.8 wt% to 3.6 wt%, or 2.25 wt% to 3.15 wt%, or 2.6 wt% carbon black;

[0151] (C) 0.01 to 0.1 wt. % of a sulfur-containing antioxidant (such as, for example, IRGANOX 1035); and / or

[0152] (D) 0.1 to 0.9 wt% of an amine-containing antioxidant (such as, for example, NAUGARD SuperQ); and / or

[0153] (E) 0.1 to 0.9 wt% of a fluorine processing aid (such as, for example, DYNAMAR FX 5912), the component weight percentages being based on the total weight of the composition (hereinafter referred to as composition 3). The cable jacket has:

[0154] (1) an aged rupture stress of 3400 psi to 4200 psi, or 3450 psi to 4100 psi, and / or

[0155] (2) an aged elongation at break of 600% to 800%, or 600% to 700%, and / or

[0156] (3) Surface roughness Ra value of 5.0 μ-in to 20 μ-in, or 6.0 μ-in to 19.0 μ-in, or 7.0 μ-in to 18.0 μ-in, or 8.0 μ-in to 17.0 μ-in, or 8.5 μ-in to 16.0 μ-in. In another embodiment, the cable jacket is the outermost layer of the cable.

[0157] In one embodiment, the carbon black of composition 3 comes from a carbon black masterbatch, and the cable jacket comprises 1.7 wt% to 5.5 wt% of a second polyethylene (carrier resin for the carbon black masterbatch) based on the total weight of the cable jacket. The second polyethylene is LLDPE, LDPE, and combinations thereof.

[0158] By way of example and not limitation, some embodiments of the present disclosure will now be described in detail in the following examples.

[0159] Example

[0160] 1. Polymerization of basic bimodal ethylene / C4-C8 α-olefin copolymers

[0161] All raw materials (monomers and comonomers) and process solvents (narrow boiling range high-purity isoparaffin solvent, Isopar-E) were purified with molecular sieves before introduction into the reaction environment. Hydrogen was supplied under pressure as a high-purity grade without further purification. The reactor monomer feed stream was pressurized to a pressure above the reaction pressure via a mechanical compressor. The solvent and comonomer feeds were pressurized to a pressure above the reaction pressure via a pump. Each catalyst component was manually diluted in batches with the purified solvent and pressurized to a pressure above the reaction pressure. All reaction feed streams were measured with mass flow meters and independently controlled using a computer-automated valve control system.

[0162] Two reactor systems are used in a series configuration. The first continuous solution polymerization reactor consists of a non-adiabatic isothermal loop reactor that simulates a continuous stirred tank reactor (CSTR) with heat removal and is filled with liquid. All fresh solvents, monomers, comonomers, hydrogen, and catalyst component feeds can be controlled independently. By passing the feed stream through a heat exchanger, the total fresh feed stream (solvent, ethylene monomer, octene comonomer, and hydrogen) entering the first reactor is temperature-controlled to maintain a single solution phase. The total fresh feed to the first polymerization reactor is injected into the reactor at three locations, wherein the reactor volume between each injection location is roughly equal. The fresh feed is controlled by each injector that receives one-third of the total fresh feed mass flow. The catalyst component is injected into the polymerization reactor at two different locations, wherein the reactor volume between each injection location is similar. A computer controls the main catalyst component feed to maintain the reactor monomer conversion under a specified target. The cocatalyst component is fed to maintain a specified Al concentration in the reactor. Immediately following each reactor feed or catalyst injection location, a static mixing element is used to mix the material flow with the circulating polymerization reactor contents. The contents of the reactor are continuously circulated through a heat exchanger which is responsible for removing the bulk of the heat of reaction and where the temperature on the coolant side is responsible for maintaining an isothermal reaction environment at a specified temperature. Circulation around the reactor loop is provided by a pump.

[0163] The second continuous solution polymerization reactor is composed of a non-adiabatic isothermal circulating loop reactor that is full of liquid and simulates a continuous stirred tank reactor (CSTR) with heat removal. All fresh solvents, ethylene monomer, octene comonomer, hydrogen and catalyst component feeds can be controlled independently. The temperature of the total fresh feed stream (solvent, ethylene monomer, octene comonomer and hydrogen) entering the second reactor is controlled by making the feed stream pass through a heat exchanger. The total fresh feed entering the second polymerization reactor is injected into the reactor at two locations, wherein the reactor volume between each injection location is roughly equal. Half of the total fresh feed mass flow is received by each injector to control the fresh feed. Catalyst component is injected into the polymerization reactor by injecting a needle. Computer control of the main catalyst component feed is to maintain the reactor monomer conversion under a specified target. The cocatalyst component is fed based on the specified molar ratio calculated with the main catalyst component. Immediately after each reactor feed injection location, the stream is mixed with the circulating polymerization reactor content with a static mixing element. The contents of the reactor are continuously circulated through a heat exchanger which is responsible for removing the bulk of the heat of reaction and where the temperature on the coolant side is responsible for maintaining an isothermal reaction environment at the specified temperature. Circulation around the second reactor loop is provided by a pump.

[0164] The effluent from the first polymerization reactor (containing solvent, ethylene monomer, octene comonomer, hydrogen, catalyst components, and polymer) exits the first reactor and is added to the second reactor. After exiting the second reactor loop, the second / final reactor effluent enters the post-reactor insulated pipe, where the total volume is approximately 21.4% of the volume of the two loop reactors combined, where the reaction continues for a period of time before entering the mixing zone, where it is deactivated by adding and reacting with a suitable reagent (water). At this same reactor outlet, other additives are added to stabilize the polymer during production and extrusion, such as tetrakis(methylene(3,5-di-tert-butyl-4-hydroxyhydrocinnamate))methane.

[0165] After catalyst deactivation and additive addition, the reactor effluent enters a devolatilization system where polymer is removed from the non-polymer stream. The separated polymer melt is pelletized and collected. The non-polymer stream passes through various devices that separate the majority of the ethylene removed from the system. Most of the solvent and unreacted comonomer are recycled back to the reactor after passing through a purification system. Small amounts of solvent and comonomer are purged from the process.

[0166] Figure 2 The reactor stream feed data flow is graphically depicted in Table 1A, which corresponds to the values ​​in Table 1A for the production examples. The data is presented so that the complexity of the solvent recycle system can be taken into account, and the reaction system can be more simply handled as a once-through flow diagram. The polymerization conditions are provided in Table 1A below, and the catalyst and cocatalyst components are described in Table 1B below.

[0167] Table 1A below provides polymerization conditions for comparative samples ("CS") and inventive examples ("IE"), ethylene monomer, and octene comonomer. In Table 2A, comparative sample 1 is DFDA-7530NT.

[0168]

[0169] Table 1B: Catalysts used in Table 1

[0170]

[0171] The properties of the base bimodal ethylene / α-olefin C4-C8 α-olefins are provided in Table 2A and Table 2B below.

[0172] Table 2A - CS1 to CS2 and IE 1 to IE Unsaturated properties of 5 .

[0173]

[0174] *Butene comonomer (all other samples octene comonomer)

[0175] $ / 1000C

[0176]

[0177] 2. Carbon black preparations for cable sheathing

[0178] The materials used to produce the cable jacketing with carbon black are provided in Table 3 below.

[0179] Table 3

[0180]

[0181] Wire (conductor) with a nominal diameter of 0.125 in was produced at 350 ft / min and coated with a jacket layer consisting of inventive examples (IE) and comparative samples (CS) using three different formulations: (1) natural (NT) with no carbon black, (2) a black (BK) formulation pre-compounded in a Banbury mixer, and (3) a black formulation added in-line at the extruder (BK in-line).

[0182] The properties of cables having a cable jacket composed of this composition are provided in Table 2 above (without carbon black) and Table 4 below (with carbon black).

[0183]

[0184]

[0185] The molecular weight distribution (Mw / Mn) of each of IE1-NT to IE5-NT (7.03-10.58) is greater than that of CS2-NT (4.52) and comparable to that of the gas-phase LLDPE of CS1-NT (10.35). Therefore, IE1-NT to IE5-NT exhibit beneficial shear thinning, as seen in the following: (i) η 0.1 / η 100 , (9.5-25.8) and (ii) high I for each of IE1-NT to IE5-NT 21 / I2 melt flow ratio (94.8-129.1). I of each of IE1-NT to IE5-NT 21 The melt flow ratio (94.8-129.1) is greater than that of the gas-phase LLDPE of CS1-NT. 21 / I2 melt flow ratio (83.2). The effect of this shear thinning can be seen in the surface roughness of the extruded wire.

[0186] Each of IE1-NT through IE5-NT had a lower surface roughness (Ra) (13.6-23.4) than that of CS2-NT (125 μ-in) and was even lower than the surface roughness of the fumed LLDPE in CS1-NT (26.5 μ-in). In addition to the improved (i.e., lower) surface roughness, each of IE1-NT through IE5-NT exhibited comparable cable jacket performance. Compared to the aged stress at break (1458.6 psi) and elongation at break (733.4%) of CS1-NT, each of IE1-NT through IE5-NT had a higher aged stress at break (2150.2 psi to 2882.2 psi) and had a high or nearly as high aged elongation at break (549.0% to 675.8%). Furthermore, all of the inventive examples exhibited equivalent environmental stress crack resistance (ESCR in Table 4) without failure, demonstrating that IE1-IE5 are suitable for cable jacket applications.

[0187] It is particularly intended that the present disclosure is not limited to the embodiments and descriptions contained herein, but includes modifications of those embodiments including portions of the embodiments and combinations of elements of different embodiments as come within the scope of the following claims.

Claims

1. A composition comprising: (A) a base bimodal ethylene / C4-C8 α-olefin copolymer having (i) a density of 0.91 g / cc to 0.93 g / cc, (ii) I between 90 and 140 21 / I2, (iii) Mw / Mn of 7.0 to 15.0, (iv) an Mz of less than 600,000 g / mol, (v) an SHI (η0.1 / η100) value of 5.0 to 30.0, (vi) 0 ppb to 80 ppb boron; and (vii) 0 ppm to 5 ppm fluorine.

2. The composition according to claim 1, comprising: (A) 90 to 97 wt% of said base bimodal ethylene / C4-C8 α-olefin copolymer; and (B) 1.3 to 4.5 wt% of carbon black.

3. The composition of any one of claims 1 to 2, wherein the base bimodal ethylene / C4-C8 α-olefin copolymer has a melt index I2 of 0.6 g / 10 min to 1.2 g / 10 min.

4. The composition of any one of claims 1 to 3, wherein the composition comprises 0 ppb boron.

5. The composition of any one of claims 1 to 4, wherein the composition comprises 0 ppm fluorine.

6. The composition according to any one of claims 1 to 5, further comprising an additive selected from the group consisting of antioxidants, processing aids, and combinations thereof.

7. The composition according to any one of claims 1 to 6, further comprising (C) 0.01% to 0.1% by weight of a sulfur-containing antioxidant; (D) 0.1 wt. % to 0.9 wt. % of an amine-containing antioxidant; and (E) 0.01 to 0.9 wt% of a fluorine processing aid.

8. The composition according to any one of claims 1 to 7, wherein the composition has a property selected from the group consisting of: (1) 2100psi to 2900psi aged fracture stress, (2) 500% to 700% of the elongation at break after aging, and A combination of them.

9. The composition of any one of claims 1 to 8, wherein the composition comprises 1.7 wt% to 5.5 wt% of the second ethylene-based polymer.

10. A cable, comprising: conductor; and A cable sheath, the cable sheath being located on the conductor, the cable sheath being composed of a composition comprising (A) a base bimodal ethylene / C4-C8 α-olefin copolymer having (i) a density of 0.91 g / cc to 0.93 g / cc, (ii) I between 90 and 140 21 / I2, (iii) Mw / Mn of 7.0 to 15.0, (iv) Mz as small as 600,000 g / mol, (v) an SHI (η0.1 / η100) value of 5.0 to 30.0, (vi) 0 ppb to 80 ppb boron, (vii) 0 ppm to 5 ppm fluorine; and The cable jacket has a surface roughness Ra value of 5.0 μ-in to 25.0 μ-in.

11. The cable according to any one of claims 10 to 11, wherein the base bimodal ethylene / C4-C8 α-olefin copolymer has a melt index I2 of 0.6 to 1.2 g / 10 min.

12. The cable of any one of claims 11 to 12, wherein the cable jacket comprises 0 ppb boron.

13. The cable of any one of claims 10 to 13, wherein the cable jacket comprises 0 ppm fluorine.

14. The cable of any one of claims 10 to 14, wherein the cable jacket has a property selected from the group consisting of: (1) 2100psi to 2900psi aged fracture stress, (2) 500% to 700% of the elongation at break after aging, and A combination of them.

15. The cable of any one of claims 10 to 15, wherein the composition of the cable jacket comprises (A) 90 to 97 wt% of said base bimodal ethylene / C4-C8 α-olefin copolymer; and (B) 1.3 to 4.5 wt% of carbon black.

16. The cable according to any one of claims 10 to 15, wherein the cable jacket further comprises (C) 0.01% to 0.1% by weight of a sulfur-containing antioxidant; (D) 0.1 wt. % to 0.9 wt. % of an amine-containing antioxidant; and (E) 0.01 to 0.9 wt% of a fluorine processing aid.

17. The cable of any one of claims 10 to 16, wherein the cable jacket comprises 1.7 wt% to 5.5 wt% of a second ethylene-based polymer.

18. The cable of any one of claims 15 to 17, wherein the cable jacket has a surface roughness Ra value of 6.0 μ-in to 19.0 μ-in.

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