Polyolefin compositions with improved volume resistivity

Abstract

The present disclosure relates to a curable composition comprising: (A) a polyolefin; (B) diatomaceous earth; (C) a crosslinker; (D) a crosslinking coagent; and optionally, (E) an additive component, wherein the curable composition exhibits improved electrical properties. The present disclosure also relates to a crosslinked polymer composition, which is the reaction product of the curable composition, wherein the crosslinked polymer composition also exhibits improved electrical properties.

Description

Background Art

[0001] Polyolefins require good electrical properties in a variety of applications, such as wire and cable, automotive weather stripping, hoses, and electrical accessories. These applications require polyolefins with high volume resistivity (VR) because high VR is generally believed to help improve resistance to electrochemical degradation (ECD).

[0002] Polyolefins can be produced via different catalyst systems, such as Ziegler-Natta (ZN) catalyst systems or non-Ziegler-Natta (non-ZN) catalyst systems. ZN catalyst systems are conventional technologies, and the catalyst efficiency is low, so a high-load catalyst and a deashing step are required for purification. Non-ZN catalyst systems have higher efficiency and do not require deashing, thereby significantly improving productivity and greatly reducing production costs. In addition, polyolefins produced by non-ZN catalysts have a more uniform composition and improved performance.

[0003] However, ZN-catalyzed polyolefins may be superior to non-ZN-catalyzed polyolefins with respect to electrical properties. For example, ZN-catalyzed EPDM is significantly superior to EPDM produced using non-ZN catalysts with respect to VR. Therefore, there is a need to improve the VR of non-ZN-catalyzed polyolefin compositions for electrical applications so that the advantages of non-ZN catalyst systems can be brought to such applications. Summary of the Invention

[0004] In certain embodiments, the present disclosure relates to a curable composition comprising: (A) a polyolefin, (B) diatomaceous earth, (C) a crosslinking agent, and (D) a crosslinking coagent. Optionally, the curable composition may further comprise (E) an additive component. The additive component (E) may comprise a metal oxide and / or an antioxidant.

[0005] In further embodiments, the present disclosure is directed to a crosslinked polymer composition that is the reaction product of a curable composition comprising: (A) a polyolefin, (B) diatomaceous earth, (C) a crosslinking agent, (D) a crosslinking coagent, and optionally, (E) an additive component comprising a metal oxide and an antioxidant.

[0006] definition

[0007] All references herein to the Periodic Table of the Elements shall be to the Periodic Table published and copyrighted by CRC Press, Inc. in 2003. Furthermore, any reference to one or more Groups shall be to the Group or Groups reflected in such Periodic Table using the IUPAC system for numbering Groups.

[0008] For purposes of U.S. patent practice, the contents of any cited 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 disclosure of definitions (to the extent not inconsistent with any definitions specifically provided in this disclosure) and common knowledge in the art.

[0009] 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 explicit values (e.g., 1 or 2 or 3 to 5 or 6 or 7), any subrange between any two explicit values is included (e.g., 1 to 2; 2 to 6; 5 to 7; 3 to 7; 5 to 6; etc.).

[0010] 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.

[0011] As used herein, the term "composition" refers to a mixture comprising the materials of the composition, as well as reaction products and decomposition products formed from the materials of the composition.

[0012] The terms "comprises," "including," "having," and their derivatives are not intended to exclude the presence of any additional components, steps, or procedures, whether or not 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 otherwise stated. In contrast, the term "consisting essentially of excludes from the scope of any subsequent recitation any other components, steps, or procedures, except those that are not essential for operability. The term "consisting of excludes any component, step, or procedure not specifically depicted or listed. Unless otherwise stated, the term "or" refers to the listed members individually and in any combination. Use of the singular includes use of the plural, and vice versa.

[0013] The term "polymer" refers to a material prepared by reacting (i.e., polymerizing) a set of monomers, where the set of monomers is either a homogeneous (i.e., only one type) set of monomers or a heterogeneous (i.e., more than one type) set of monomers. The term polymer as used herein includes the term "homopolymer," which refers to a polymer prepared from a homogeneous set of monomers, and the term "interpolymer," as defined below.

[0014] The term "interpolymer" refers to a polymer prepared by polymerizing at least two different types of monomers. This term includes both "copolymers," i.e., polymers prepared from two different types of monomers, and polymers prepared from more than two different types of monomers, such as terpolymers, tetrapolymers, etc. This term also encompasses all forms of interpolymers, such as random, block, homogeneous, heterogeneous, etc.

[0015] As used herein, the term "ethylene / α-olefin interpolymer" refers to a polymer that comprises, in polymerized form, a majority weight percent of ethylene (based on the weight of the interpolymer) and at least one comonomer that is an α-olefin. The ethylene / α-olefin interpolymer can be a random or block interpolymer. The terms "ethylene / α-olefin copolymer" and "ethylene / α-olefin multi-block interpolymer" are encompassed by the term "ethylene / α-olefin interpolymer."

[0016] As used herein, the term "ethylene / α-olefin copolymer" refers to a copolymer comprising, in polymerized form, a majority weight percent of ethylene (based on the weight of the copolymer) and an α-olefin as a comonomer, wherein ethylene and the α-olefin are the only two monomer types. The ethylene / α-olefin copolymer can be a random or block copolymer.

[0017] The term "ethylene / α-olefin multi-block interpolymer" or "olefin block copolymer" refers to an interpolymer comprising, in polymerized form, ethylene and one or more copolymerizable α-olefin comonomers, characterized by multiple blocks or segments of two or more (preferably three or more) polymerized monomer units that differ in chemical or physical properties. Specifically, this term refers to polymers that contain two or more (preferably three or more) chemically distinct regions or segments (referred to as "blocks") joined in a linear manner, rather than in a pendant or grafted manner, i.e., polymers that contain chemically distinct units joined end-to-end (covalently bonded) with respect to polymerized functionality. The blocks differ in the amount or type of comonomer incorporated therein, density, amount of crystallinity, type of crystallinity (e.g., polyethylene versus polypropylene), crystallite size attributable to the polymer of such composition, type or degree of tacticity (isotactic or syndiotactic), regioregularity or regioirregularity, amount of branching (including long chain branching or hyperbranching), uniformity, and / or any other chemical or physical property. Block copolymers are characterized by unique distributions of both polymer polydispersity (PDI or Mw / Mn) and block length distribution, for example, based on the effect of one or more shuttling agents used in combination with the catalyst system. Non-limiting examples of the presently disclosed olefin block copolymers and methods for making the same are disclosed in U.S. Pat. Nos. 7,858,706 B2, 8,198,374 B2, 8,318,864 B2, 8,609,779 B2, 8,710,143 B2, 8,785,551 B2, and 9,243,090 B2, all of which are incorporated herein by reference in their entirety.

[0018] As used herein, the term "ethylene / α-olefin / diene interpolymer" refers to a polymer comprising ethylene, an α-olefin, and a diene in polymerized form. In one embodiment, the "ethylene / α-olefin / diene interpolymer" comprises a majority weight percent ethylene (based on the weight of the interpolymer).

[0019] As used herein, the term "propylene / α-olefin interpolymer" refers to a polymer that comprises, in polymerized form, a majority weight percent propylene (based on the weight of the interpolymer) and at least one comonomer that is an α-olefin (wherein ethylene is considered an α-olefin). The propylene / α-olefin interpolymer can be a random or block interpolymer. The term "propylene / α-olefin interpolymer" includes the term "propylene / α-olefin copolymer."

[0020] As used herein, the term "propylene / α-olefin copolymer" refers to a copolymer comprising, in polymerized form, a majority weight percent of propylene (based on the weight of the copolymer) and an α-olefin as a comonomer, with propylene and the α-olefin as the only two monomer types. The propylene / α-olefin copolymer can be a random or block copolymer.

[0021] "Polyolefin" refers to a polymer produced by the polymerization of olefins as monomers, wherein the olefin monomer is a linear, branched, or cyclic compound of carbon and hydrogen having at least one double bond. Thus, as used herein, the term "polyolefin" includes and encompasses the terms "ethylene / α-olefin interpolymer," "ethylene / α-olefin copolymer," "ethylene / α-olefin multi-block interpolymer," "ethylene / α-olefin olefin / diene interpolymer," "propylene / α-olefin interpolymer," and "propylene / α-olefin copolymer."

[0022] As used herein, the term "Ziegler Natta catalyst" refers to a vanadium-based catalyst. As used herein, "Ziegler Natta catalyzed polymer" or similar terms refers to a polymer having a vanadium content greater than 0.4 ppm according to the methods disclosed herein or similar methods.

[0023] As used herein, the term "non-Ziegler Natta catalyst" refers to a Group 4 metal-based catalyst, including catalysts known in the art as metallocene catalysts, constrained geometry complex (CGC) catalysts, post-metallocene catalysts, molecular catalysts, and advanced molecular catalysts. As used herein, "non-Ziegler Natta-catalyzed polymers" and similar terms refer to polymers having a Group 4 metal content of 0.3 ppm or greater according to the methods disclosed herein or similar methods. "Non-Ziegler Natta-catalyzed polymers" may also have a vanadium content of less than or equal to 0.4 ppm according to the methods disclosed herein or similar methods.

[0024] Test Method

[0025] Each feature described in this disclosure is according to the following method.

[0026] Mooney viscosity test: Mooney viscosity was measured in a Mooney shear disc viscometer according to ASTM 1646. The instrument was an Alpha Technologies Mooney Viscometer 2000. The torque of the rotor was measured at 2 rpm by a torque transducer. After the platen was closed, the sample was preheated for 1 minute (min). The motor was then started and the torque was recorded over a 4-minute period. The results were reported in Mooney units (MU) as "ML (1+4) at 125°C". The term "ML" means that a large rotor, "Mooney Large", was used in the viscosity test, where the large rotor is a standard size rotor. The Mooney viscosity (MV) measures the resistance to flow of a polymer at relatively low shear rates and indicates the fluidity of the polymer.

[0027] density: Density is measured according to ASTM D792, Method B. The results are expressed in grams per cubic centimeter (g / cc or g / cm 3 )Record.

[0028] Monomer content: The ethylene and propylene contents of the interpolymers are determined as weight percent by Fourier transform infrared (FTIR) analysis according to ASTM D3900. The diene (ENB) content of the interpolymers is determined as weight percent by Fourier transform infrared (FTIR) analysis according to ASTM D6047.

[0029] Residual Elemental Analysis: Residual elemental analysis was performed using inductively coupled plasma-atomic emission spectroscopy (ICP-AES) to determine the metal content of the interpolymer (e.g., vanadium content, Group 4 metal content, titanium content, hafnium content, and / or zirconium content). For ICP-AES analysis, the sample was weighed into a quartz tube, and 1 mL of water and 3 mL of nitric acid were added to the sample. The sample was placed in a heat block at 115°C for 30 minutes. The sample was then placed in an UltraWave microwave oven, where it was digested at 250°C. Following microwave digestion, the sample was diluted and analyzed by Perkin Elmer ICP for aluminum, calcium, chromium, titanium, and vanadium. Results are reported in parts per million (ppm).

[0030] Gel Permeation Chromatography ("GPC"): The chromatographic system consisted of a PolymerChar GPC-IR (Valencia, Spain) high temperature GPC chromatograph equipped with an internal IR5 infrared detector (IR5). The autosampler oven chamber was set to 160°C, and the column chamber was set to 150°C. The columns used were four Agilent "Mixed A" 30 cm 20 micron linear mixed bed columns and a 20 μm pre-column. The chromatographic solvent used was 1,2,4 trichlorobenzene and contained 200 ppm of butylated hydroxytoluene (BHT). The solvent source was sparged with nitrogen. The injection volume used was 200 microliters, and the flow rate was 1.0 ml / min.

[0031] The GPC column set was calibrated using 21 narrow molecular weight distribution polystyrene standards with molecular weights ranging from 580 to 8,400,000 and arranged in 6 "cocktail" mixtures with at least ten times the molecular weight between the individual molecular weights. Standards were purchased from Agilent Technologies. Polystyrene standards were prepared in an amount of 0.025 grams in 50 ml of solvent with a molecular weight equal to or greater than 1,000,000, and in an amount of 0.05 grams in 50 ml of solvent with a molecular weight less than 1,000,000. The polystyrene standards were gently stirred at 80°C for 30 minutes to dissolve the polystyrene standards. The polystyrene standard peak molecular weight was converted to polyethylene molecular weight using equation 1 (as described by Williams and Ward, J. Polym. Sci., Polym. Let., 6, 621 (1968)):

[0032] M 聚乙烯 =A×(M 聚苯乙烯 ) B (EQ1)

[0033] Wherein M is the molecular weight, A has a value of 0.4315 and B equals 1.0.

[0034] A fifth-order polynomial was used to fit the corresponding polyethylene equivalent calibration points. Small adjustments to A (approximately 0.375 to 0.445) were made to correct for column resolution and band broadening effects, resulting in a linear homopolymer polyethylene standard at 120,000 Mw.

[0035] Total plate counts were performed on the GPC column set using decane (prepared at 0.04 g in 50 mL TCB and dissolved under gentle agitation for 20 minutes). Plate counts (Equation 2) and symmetry (Equation 3) were measured with a 200 μL injection according to the following equations:

[0036]

[0037] Where RV is the retention volume in milliliters, peak width is in milliliters, peak maximum is the maximum height of the peak, and 1 / 2 height is 1 / 2 the height of the peak maximum.

[0038]

[0039] Where RV is the retention volume in milliliters, and peak width is in milliliters, peak maximum is the maximum peak position, tenth height is 1 / 10 the height of the peak maximum, and where post-peak refers to the tail of the peak at a later retention volume than the peak maximum, and where pre-peak refers to the front of the peak at an earlier retention volume than the peak maximum. The plate count of the chromatography system should be greater than 18,000, and the symmetry should be between 0.98 and 1.22.

[0040] 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.

[0041] Based on the GPC results, the internal IR5 detector (measurement channel) of the PolymerChar GPC-IR spectrometer was used, according to Equations 4-6, using the PolymerChar GPCOne TM The software calculates Mn, Mw, and Mz from the baseline-subtracted IR chromatogram at each equidistant data collection point (i) and the polyethylene equivalent molecular weight obtained from the narrow standard calibration curve at point (i) according to Equation 1.

[0042]

[0043]

[0044]

[0045] 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)). It was then assumed that any change in the decane marker peak time was related to a linear change in flow rate (Flow Rate (Effective)) throughout the run. To facilitate the highest accuracy in measuring the RV of the flow marker peak, a least squares fitting procedure was used to fit the peak of the flow marker concentration chromatogram to a quadratic equation. The first derivative of the quadratic equation was then used to solve for the true peak position. After calibrating the system based on the flow marker peak, the effective flow rate (relative to the narrow standard calibration) was calculated as Equation 7. By PolymerChar GPCOne 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 + / - 1% of the nominal flow rate.

[0046] Effective flow rate = effective flow rate * (RV (FM calibration) / RV (FM sample) (EQ7)

[0047] Moving Die Rheometer (MDR): Cure characteristics at 180°C were measured using a Prescott Rheo-line MDR according to ASTM D5289-15. The torque versus time curve for each sample was recorded at given time intervals. The maximum torque applied by the MDR during a 25-minute test interval (MH) was recorded in deciNewton meters (dNm). The MH generally corresponds to the maximum torque applied at 25 minutes. The time required for the torque to reach x% of the MH (t x ) is recorded in minutes. x It is a standardized measurement used to understand the curing kinetics of each resin. The time to reach 90% of the MH (t 90 ).

[0048] Volume resistivity: Volume resistivity was determined using the following method based on ASTM D257. Volume resistivity was determined using a Keithley 6517B electrometer in combination with a Keithley 8009 test fixture. The Keithley 8009 test chamber was located within a forced-air oven capable of operating at high temperatures (maximum temperature 80°C). The leakage current was recorded from the instrument via software, and the volume resistivity (VR) was calculated using the following equation:

[0049]

[0050] Where ρ is the volume resistivity in ohm.cm, V is the applied voltage in volts, and A is the electrode contact area in cm 2 , I is the leakage current in amperes recorded after 10 minutes of applied voltage, and t is the thickness of the sample. The thickness of the compression molded film was measured before testing. Five points on the film were measured to obtain the average thickness for use in the calculations. Testing was performed at room temperature and 500 volts. Two compression molded films were tested, and the reported VR is the average of the two measurements. Results are reported in ohm-centimeters (ohm.cm). DETAILED DESCRIPTION

[0051] polyolefins

[0052] The (A) polyolefin of the present disclosure can be any interpolymer in which an olefin is the main monomer. That is, the polyolefin can be an interpolymer comprising a majority of polymerized units derived from an olefin monomer, wherein the interpolymer further comprises units derived from a comonomer that is different from the olefin monomer and is a C2-C30 linear, branched, or cyclic α-olefin. For the purposes of this disclosure, ethylene is an α-olefin. Non-limiting examples of C2-C30 α-olefins used as comonomers include ethylene, propylene, 1-butene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, and 1-octadecene.

[0053] In certain embodiments, the polyolefin is an ethylene / α-olefin interpolymer. Non-limiting examples of ethylene / α-olefin interpolymers include interpolymers of ethylene and C3-C8 α-olefins or C4-C8 α-olefins, such as ethylene / propylene interpolymers, ethylene / 1-butene interpolymers, ethylene / 1-hexene interpolymers, ethylene / 1-octene interpolymers, and combinations thereof.

[0054] In certain embodiments, the polyolefin is an ethylene / α-olefin copolymer. Non-limiting examples of ethylene / α-olefin copolymers include copolymers of ethylene and C3-C8 α-olefins or C4-C8 α-olefins, such as ethylene / propylene copolymers, ethylene / 1-butene copolymers, ethylene / 1-hexene copolymers, ethylene / 1-octene copolymers, and combinations thereof.

[0055] In certain embodiments, the polyolefin is an ethylene / α-olefin / diene interpolymer, as discussed further below.

[0056] In further embodiments, the polyolefin is an ethylene / α-olefin multi-block interpolymer or an olefin block copolymer as defined herein.

[0057] In certain embodiments, the polyolefin is a propylene / α-olefin interpolymer. Non-limiting examples of propylene / α-olefin interpolymers include propylene / ethylene interpolymers, propylene / 1-butene interpolymers, propylene / 1-hexene interpolymers, propylene / 1-octene interpolymers, and combinations thereof. In further embodiments, the polyolefin is a propylene / α-olefin copolymer. Non-limiting examples of propylene / α-olefin copolymers include propylene / ethylene copolymers, propylene / 1-butene copolymers, propylene / 1-hexene copolymers, propylene / 1-octene copolymers, and combinations thereof.

[0058] In certain embodiments, the polyolefin is free of heteroatoms. As used herein, the term "heteroatom" refers to an atom other than carbon or hydrogen. A heteroatom can be a non-carbon atom of Groups IV, V, VI, and VII of the Periodic Table of the Elements. Non-limiting examples of heteroatoms include: F, N, O, P, B, S, and Si.

[0059] In certain embodiments, the polyolefin according to the methods disclosed herein or similar methods has a vanadium content of (or includes vanadium in an amount of) less than or equal to 0.4 ppm or less than or equal to 0.3 ppm. In further embodiments, the polyolefin according to the methods disclosed herein or similar methods has a Group 4 metal content of (or includes a Group 4 metal in an amount of) greater than or equal to 0.3 ppm, or greater than or equal to 0.4 ppm, or greater than or equal to 0.5 ppm, or greater than or equal to 0.6 ppm. In further embodiments, the polyolefin has a vanadium content of (or includes vanadium in an amount of) less than or equal to 0.4 ppm or less than or equal to 0.3 ppm and / or a Group 4 metal content of (or includes a Group 4 metal in an amount of) greater than or equal to 0.3 ppm, or greater than or equal to 0.4 ppm, or greater than or equal to 0.5 ppm, or greater than or equal to 0.6 ppm.

[0060] In further embodiments, the polyolefin has one, some, or all of the following: a Mooney viscosity (ML 1+4 at 125°C) from greater than zero to 100 MU, or from 5 to 100 MU, according to ASTM D1646; a density from 0.850 g / cc to 0.920 g / cc, according to ASTM D792, Method B; from 40 wt% to 80 wt%, or from 50 wt% to 80 wt% polymerized ethylene; from zero to 10 wt% polymerized diene; and a molecular weight distribution (MWD or Mw / Mn) from 1 to 7, or from 1 to 5, or from 2 to 4.

[0061] Suitable polyolefins include, but are not limited to, those sold under the trade name NORDEL TM ENGAGE TM 、INFUSE TM and Versify TMAvailable from The Dow Chemical Company under the trade name Exact TM and Vistamaxx TM Available from ExxonMobil Chemical Company and under the trade name LUCENE TM Those purchased from LG Chem.

[0062] The polyolefin can have any combination of the embodiments described herein.

[0063] Ethylene / α-olefin / diene interpolymer

[0064] In embodiments where (A) the polyolefin of the present disclosure is an ethylene / α-olefin / diene interpolymer, the ethylene / α-olefin / diene interpolymer comprises ethylene, an α-olefin, and a diene in polymerized form. The diene may be conjugated or non-conjugated. Suitable examples of α-olefins include C3-C20 α-olefins or C3-C10 α-olefins. Suitable examples of dienes include C4-C40 non-conjugated dienes.

[0065] The α-olefin can be an aliphatic or aromatic compound. In some embodiments, the α-olefin is a C3-C10 aliphatic α-olefin. In some embodiments, the α-olefin is selected from the group consisting of propylene, 1-butene, 1-hexene, and 1-octene. In certain embodiments, the α-olefin is propylene.

[0066] In certain embodiments, the diene is an acyclic or cyclic non-conjugated diene. Non-limiting examples of non-conjugated dienes include linear acyclic dienes such as 1,4-hexadiene, 1,5-heptadiene, and 1,9-decadiene; branched acyclic dienes such as 5-methyl-1,4-hexadiene, 2-methyl-1,5-hexadiene, 6-methyl-1,5-heptadiene, 7-methyl-1,6-octadiene, 3,7-dimethyl-1,6-octadiene, 3,7-dimethyl-1,7-octadiene, 5,7-dimethyl-1,7-octadiene, and mixed isomers of dihydromyrcene; monocyclic ali ...7-octadiene, 5,7-dimethyl-1,7-octadiene, and mixed isomers of -cyclohexadiene, 1,5-cyclooctadiene, and 1,5-cyclododecadiene; polycyclic alicyclic fused and bridged cyclic dienes such as tetrahydroindene and methyltetrahydroindene; alkenyl, alkylene, cycloalkenyl, and cycloalkylene norbornenes such as 5-methylene-2-norbornene (MNB), 5-ethylidene-2-norbornene (ENB), 5-vinyl-2-norbornene, 5-propenyl-2-norbornene, 5-isopropylidene-2-norbornene, 5-(4-cyclopentenyl)-2-norbornene, and 5-cyclohexylidene-2-norbornene. In further embodiments, the diene is a non-conjugated diene selected from the group consisting of ENB, dicyclopentadiene, 1,4-hexadiene, and 7-methyl-1,6-octadiene. In further embodiments, the diene is ENB.

[0067] In some embodiments, the ethylene / α-olefin / diene interpolymer is an ethylene / propylene / diene (EPDM) interpolymer. In further embodiments, the ethylene / α-olefin / diene interpolymer is an ethylene / propylene / diene (EPDM) interpolymer wherein the diene is ENB.

[0068] In some embodiments, the ethylene / α-olefin / diene interpolymer is prepared using a non-Ziegler-Natta catalyst, such as a CGC catalyst, an advanced molecular catalyst, or a post-metallocene catalyst. Examples of such catalysts include, but are not limited to, those disclosed in U.S. Patent Nos. 5,272,236; 5,278,272; and 8,101,696, as well as publications US 2005 / 0164872 and WO 2007 / 136494, each of which is incorporated herein by reference in its entirety.

[0069] In some embodiments, the ethylene / α-olefin / diene interpolymer has a Mooney viscosity (ML 1+4 at 125°C) of from greater than 0 to 100 MU, or from 5 to 100 MU, according to ASTM D 1646. In certain embodiments, the ethylene / α-olefin diene interpolymer has a Mooney viscosity (ML 1+4 at 125°C) of from 5 MU, or 10 MU, or 15 MU, or 18 MU, or 20 MU, or 25 MU, or 30 MU, or 35 MU to 40 MU, or 45 MU, or 50 MU, or 55 MU, or 60 MU, or 65 MU, or 70 MU, or 75 MU, or 80 MU, or 85 MU, or 90 MU, or 99 MU, or 100 MU, according to ASTM D 1646.

[0070] In further embodiments, the ethylene / α-olefin diene interpolymer has a Mooney viscosity (ML 1+4 at 125°C) from greater than 0 to 100 MU, or from 5 MU to 100 MU, or from 15 MU to 100 MU, or from 15 MU to 99 MU, or from 15 MU to 90 MU, or from 15 MU to 80 MU, or from 15 MU to 70 MU, or from 15 MU to 60 MU, or from 15 MU to 50 MU, or from 18 MU to 45 MU, or from 18 MU to 40 MU, according to ASTM D1646.

[0071] In certain embodiments, the ethylene / α-olefin diene interpolymer has a density from 0.850 g / cc, or 0.860 g / cc, or from 0.870 g / cc to 0.880 g / cc, or 0.890 g / cc, or 0.900 g / cc, or 0.910 g / cc, or 0.920 g / cc according to ASTM D792, Method B. In further embodiments, the ethylene / α-olefin diene interpolymer has a density from 0.850 g / cc to 0.920 g / cc, or from 0.860 g / cc to 0.910 g / cc, or from 0.860 g / cc to 0.900 g / cc, or from 0.860 g / cc to 0.890 g / cc, or from 0.860 g / cc to 0.880 g / cc according to ASTM D792, Method B.

[0072] In some embodiments, the ethylene / α-olefin / diene interpolymer comprises a majority amount of polymerized ethylene, based on the weight of the interpolymer. In certain embodiments, the ethylene / α-olefin / diene interpolymer comprises from 40 wt%, or 45 wt%, or 50 wt%, or 55 wt%, or 60 wt%, or 68 wt% to 70 wt%, or 71 wt%, or 75 wt%, or 80 wt%, or 85 wt% polymerized ethylene. In further embodiments, the ethylene / α-olefin / diene interpolymer comprises from 40 wt% to 80 wt%, or from 50 wt% to 80 wt%, or from 55 wt% to 70 wt% polymerized ethylene.

[0073] In certain embodiments, the ethylene / α-olefin / diene interpolymer comprises from greater than 0 wt%, or 0.5 wt%, or 1 wt%, or 2 wt%, or 3 wt%, or 3.5 wt%, or 4 wt%, or 4.5 wt%, or 4.7 wt% to 4.9 wt%, or 5 wt%, or 6 wt%, or 7 wt%, or 7.5 wt%, or 8 wt%, or 8.5 wt%, or 9 wt%, or 10 wt% polymerized diene, based on the weight of the interpolymer. In further embodiments, the ethylene / α-olefin / diene interpolymer comprises from greater than zero to 10 wt%, or from 0.5 wt% to 9 wt%, or from 0.5 wt% to 8.5 wt% polymerized diene, such as polymerized ENB.

[0074] In some embodiments, the ethylene / α-olefin / diene interpolymers have a molecular weight distribution (MWD or Mw / Mn) from 1 to 7, or from 1 to 5, or from 1.5 to 5, or from 2 to 4.

[0075] According to the methods disclosed herein or similar methods, the ethylene / α-olefin / diene interpolymers can have the following metal contents: In certain embodiments, the ethylene / α-olefin / diene interpolymers have a vanadium content (or include vanadium in an amount) less than or equal to 0.4 ppm, or less than or equal to 0.3 ppm.

[0076] In certain embodiments, the ethylene / α-olefin / diene interpolymer has a titanium content (or comprises titanium in an amount of) greater than, or equal to, 0.3 ppm, or greater than, or equal to, 0.4 ppm, or greater than, or equal to, 0.5 ppm, or greater than, or equal to, 0.6 ppm.

[0077] In certain embodiments, the ethylene / α-olefin / diene interpolymer has a zirconium content (or comprises zirconium in an amount of) greater than, or equal to, 0.3 ppm, or greater than, or equal to, 0.4 ppm, or greater than, or equal to, 0.5 ppm, or greater than, or equal to, 0.6 ppm.

[0078] In certain embodiments, the ethylene / α-olefin / diene interpolymer has a hafnium content (or comprises hafnium in an amount of) greater than, or equal to, 0.3 ppm, or greater than, or equal to, 0.4 ppm, or greater than, or equal to, 0.5 ppm.

[0079] In certain embodiments, the ethylene / α-olefin / diene interpolymer has a Group 4 metal content (including the Group 4 metal in an amount of) greater than, or equal to, 0.3 ppm, or greater than, or equal to, 0.4 ppm, or greater than, or equal to, 0.5 ppm, or greater than, or equal to, 0.6 ppm.

[0080] In certain embodiments, the ethylene / α-olefin / diene interpolymer comprises titanium, zirconium, and / or hafnium in an amount greater than, or equal to, 0.3 ppm, or greater than, or equal to, 0.4 ppm, or greater than, or equal to, 0.5 ppm, or greater than, or equal to, 0.6 ppm.

[0081] In certain embodiments, the ethylene / α-olefin / diene interpolymer has a vanadium content less than, or equal to, 0.4 ppm, or less than, or equal to, 0.3 ppm, or a Group 4 metal content greater than, or equal to, 0.3 ppm, or greater than, or equal to, 0.4 ppm, or greater than, or equal to, 0.5 ppm, or greater than, or equal to, 0.6 ppm.

[0082] In certain embodiments, the ethylene / α-olefin / diene interpolymers are free of heteroatoms. As used herein, the term "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 of the Elements. Non-limiting examples of heteroatoms include: F, N, O, P, B, S, and Si.

[0083] The ethylene / α-olefin / diene interpolymers of the present disclosure may comprise two or more embodiments as described herein, or may be any combination of the embodiments described herein.

[0084] diatomite

[0085] The curable composition of the present disclosure further comprises (B) diatomaceous earth. In certain embodiments, the diatomaceous earth of the present disclosure is a natural combination of classic Neuburg diatomaceous earth, micronized Neuburg silica, and layered kaolinite: a loose mixture that cannot be separated by physical means.

[0086] In further embodiments, the diatomaceous earth of the present disclosure is classic Neuburg diatomaceous earth having a particle size distribution (D50) of 1.5 to 4 based on Fraunhofer analysis of diffraction spectra performed with a Matersizer 3000 laser device from Malvern Instruments.

[0087] In certain embodiments, the diatomaceous earth of the present disclosure is classic Neuburg diatomaceous earth, which is commercially available from Hoffman Mineral GmbH under the name Sillitin. In certain embodiments, the diatomaceous earth of the present disclosure is classic Neuburg diatomaceous earth, which is commercially available from Hoffman Mineral GmbH as Sillitin N 85 or Sillitin Z 86.

[0088] The diatomaceous earth can be a blend of two or more classic Neuburg diatomaceous earths.The diatomaceous earth can be any combination of the embodiments disclosed herein.

[0089] crosslinking agent

[0090] The curable composition of the present disclosure can be cured to form a cross-linked polymer composition. The cross-linked polymer composition is the reaction product of the curable composition resulting from curing. Therefore, in certain embodiments, the curable composition further comprises (C) a cross-linking agent.

[0091] Non-limiting examples of suitable crosslinking agents include peroxides; phenols; azides; aldehyde-amine reaction products; substituted ureas; substituted guanidines; substituted xanthates; substituted dithiocarbamates; sulfur-containing compounds such as thiazoles, sulfenamides, thiuram disulfides, p-quinonedioxime, dibenzop-quinonedioxime, sulfur; imidazoles; silanes; metal oxides such as zinc, magnesium and lead oxides; dinitroso compounds such as p-quinonedioxime and p,p'-dibenzoylquinonedioxime; and phenol-formaldehyde resins containing hydroxymethyl or halomethyl functional groups, and combinations thereof.

[0092] Suitable cross-linking agents include sulfur-based cross-linking agents, such as elemental sulfur. When sulfur-based curing agents are used, accelerators and cure activators such as amines, disulfides, guanidines, thioureas, thiazoles, thiurams, sulfenamides, dithiocarbamates, xanthates, 4,4'-dimorpholinedithioate, thiuram disulfides and polysulfides, alkylphenol disulfides and 2-morpholino-dithiobenzothiazole, tetramethylthiuram disulfide (TMTD), dipentamethylenethiuram tetrasulfide (DPTT), 2-mercaptobenzothiazole (MBT), 2-mercaptobenzothiazole disulfide (MBTS), zinc 2-mercaptobenzothiazole (ZMBT), zinc diethyldithiocarbamate (ZDEC), zinc dibutyldithiocarbamate (ZDBC), dipentamethylenethiuram tetrasulfide (DPTT), N-tert-butylbenzothiazole-2-sulfonamide (TBBS), and mixtures thereof may also be used.

[0093] Additional crosslinking agents include, but are not limited to, phenolic resins, azides, aldehyde-amine reaction products, vinyl silanes, hydrosilylation agents, substituted ureas, substituted guanidines, substituted xanthates, substituted dithiocarbamates, and combinations thereof. The crosslinking agent can be a phenolic curing agent or a peroxide curing agent, with an optional coagent, or a hydrosilylation crosslinking agent with a hydrosilylation catalyst, or dibutyltin dilaurate ("DBTDL"), with an optional coagent alumina trihydrate ("ATH"). Popular industrial catalysts are "Speier's catalyst," H2PtCl6, and Karstedt's catalyst, an olefin-stabilized platinum(0) catalyst.

[0094] In a preferred embodiment, the crosslinking agent may be one or more organic peroxides, including but not limited to alkyl peroxides, aryl peroxides, peroxyesters, peroxycarbonates, diacyl peroxides, peroxyketals, cyclic peroxides, dialkyl peroxides, peroxyesters, peroxydicarbonates, or a combination of two or more thereof. Examples of peroxides include but are not limited to di-tert-butyl peroxide, dicumyl peroxide, di(3,3,5-trimethylhexanoyl)peroxide, tert-butyl peroxypivalate, tert-butyl peroxyneodecanoate, di(sec-butyl)peroxydicarbonate, tert-amyl peroxyneodecanoate, 1,1-di-tert-butylperoxy-3,3,5-trimethylcyclohexane, tert-butyl-cumyl peroxide, 2,5-dimethyl-2,5-di(tert-butyl-peroxy)hexane, 1,3-bis(tert-butyl-peroxy-isopropyl)benzene, or a combination thereof. An exemplary crosslinking agent is available from Arkema under the trade name or available from Akzo Nobel under the trade name Dicumyl peroxide is commercially available. Additional exemplary cross-linking agents are available from Vanderbilt Chemicals. DBPH-50. When the crosslinking agent is a peroxide, certain processing aids and curing activators such as stearic acid and ZnO can also be used.

[0095] Non-limiting examples of suitable organic peroxides include dicumyl peroxide; lauryl peroxide; benzoyl peroxide; tert-butyl perbenzoate; di(tert-butyl peroxide); cumene hydroperoxide; 2,5-dimethyl-2,5-di(tert-butyl-peroxy)hexyne-3; 2,5-dimethyl-2,5-di(tert-butyl-peroxy)hexane; tert-butyl hydroperoxide; isopropyl percarbonate; α,α′-bis(tert-butyl)peroxy tert-Butylperoxy)diisopropylbenzene, tert-Butylperoxy-2-ethylhexyl monocarbonate; 1,1-bis(tert-butylperoxy)-3,5,5-trimethylcyclohexane; 2,5-dimethyl-2,5-dihydroxyperoxide; tert-Butylperoxycumyl; α,α'-bis(tert-butylperoxy)-p-diisopropylbenzene; bis(1,1-dimethylethyl)peroxide; bis(1,1-dimethylpropyl)peroxide;

[0096] 2,5-Dimethyl-2,5-bis(1,1-dimethylethylperoxy)hexane; 2,5-dimethyl-2,5-bis(1,1-

[0097] dimethylethylperoxy)hexyne; 4,4-bis(1,1-dimethylethylperoxy)valeric acid; butyl ester; 1,1-

[0098] Bis(1,1-dimethylethylperoxy)-3,3,5-trimethylcyclohexane; Benzoyl peroxide; Tert-butyl

[0099] Peroxybenzoates; di-tert-amyl peroxide ("DTAP"); bis(α-tert-butylperoxyisopropyl)benzene ("BIPB"); isopropylcumyl tert-butyl peroxide; tert-butylcumyl peroxide; di-tert-butyl peroxide; 2,5-bis(tert-butylperoxy)-2,5-dimethylhexane; 2,5-bis(tert-butylperoxy)-2,5-dimethylhexyne-3,1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane; 2,5-bis(tert-amylperoxy)-2, 5-dimethylhexane; isopropylcumyl peroxide; butyl 4,4-di(tert-butylperoxy)valerate; di(isopropylcumyl) peroxide; 2,5-di(tert-butylperoxy)-2,5-diphenylhexane; bis(α-methylbenzyl) peroxide; benzoyl peroxide; tert-butyl perbenzoate; 3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxane; bis(tert-butylperoxy)-diisopropylbenzene; di-2-tert-butylperoxyisopropylbenzene; and combinations thereof.

[0100] Non-limiting examples of suitable commercially available organic peroxides include those sold under the trade names Those available from AkzoNobel, and those sold under the trade names like F40P are those available from Arkema.

[0101] As discussed further below, when peroxide-based curing agents are used, a co-activator or adjuvant may be used in combination therewith. Suitable co-activators include, but are not limited to, trimethylolpropane triacrylate (TMPTA), trimethylolpropane trimethacrylate (TMPTMA), triallyl cyanurate (TAC), triallyl isocyanurate (TAIC), and 1,4-phenylenedimaleimide (available from TCI Chemicals).

[0102] When a crosslinking agent is used, crosslinking can be induced by activating the crosslinking agent in the curable composition. The crosslinking agent can be activated by exposing it to a temperature above its decomposition temperature. The temperature range is 50°C to 300°C, such as 80°C to 275°C. The time can be determined by one of ordinary skill in the art based on the selected polymer and curing component.

[0103] Alternatively, the crosslinking agent can be activated by exposing it to radiation that causes the generation of free radicals from the crosslinking agent. Non-limiting examples of suitable radiation include UV or visible radiation, electron beams or beta rays, gamma rays, X-rays or neutron rays. It is believed that radiation activates crosslinking by generating free radicals in the polymer, which can then be combined and crosslinked. The radiation dose depends on many factors and can be determined by those skilled in the art. When the crosslinking agent is a peroxide photoinitiator, such as dibenzoyl peroxide, cumene hydroperoxide, di-tert-butyl peroxide, diacetyl peroxide, hydrogen peroxide, peroxodisulfate and 2,2-bis (tert-butyl peroxy) -2,5-dimethylhexane, UV or visible radiation activation can occur.

[0104] In some embodiments, dual-cure systems comprising at least two activation methods, such as a combination selected from heat, moisture cure, and radiation, can be effectively used. For example, it may be desirable to employ a peroxide crosslinker in combination with a silane crosslinker, a peroxide crosslinker in combination with radiation, a sulfur-containing crosslinker in combination with a silane crosslinker, and the like. One skilled in the art will readily be able to select the amount of crosslinker based on the desired level of crosslinking, the characteristics of the polymer (e.g., molecular weight, molecular weight distribution, comonomer content), the presence of crosslinking enhancing coagents, other additives, and the like.

[0105] Crosslinking aids

[0106] In certain embodiments where the curable composition of the present disclosure includes a peroxide crosslinker, the curable composition may further include (D) a crosslinking aid. The crosslinking aid may be any one or a mixture of the following: an ester, an ether, a ketone, a cyanurate, an isocyanurate, a phosphate, an orthoformates, an aliphatic or aromatic ether containing at least two and preferably three unsaturated groups, such as an allyl group, a vinyl group, or an acrylate. The number of carbon atoms in the aid may range from 9 to 40 or more, and preferably from 9 to 20.

[0107] Specific examples of adjuvants include, but are not limited to, trimethylolpropane trimethacrylate (TRIM); triallyl cyanurate (TAC); triallyl-1,3,5-triazine-2,4,6(1H,3H,5H)-trione also known as triallyl isocyanurate (TAIC); hexaallyl melamine; triallyl phosphate (TAP); triallyl orthoformate; tetraallyloxyethane; triallyl benzene-1,3,5-tricarboxylate; diallyl phthalate; zinc dimethacrylate; ethoxylated bisphenol A dimethacrylate; methacrylate-terminated monomers having an average chain length of C14 or C15; pentaerythritol tetraacrylate; pentaerythritol pentaacrylate; pentaerythritol triacrylate; dimethylolpropane tetraacrylate; ethoxylated trimethylolpropane triacrylate; trimethylolpropane triacrylate; 2,4,6-triallyl-1,3,5-trione; 2,4-diphenyl-4-methyl-1-pentene; triallyl trimellitate (TATM); 3,9-divinyl-2,4,8,10-tetraoxaspiro[5.5]undecane (DVS); and α-methylstyrene dimer (AMSD); 1,2-polybutadiene; divinylbenzene; trimethylolpropane trimethacrylate; polyethylene glycol dimethacrylate; ethylene glycol dimethacrylate; allyl methacrylate; NN'-m-phenylene bismaleimide; toluene bismaleimide-p-quinonedioxime; nitrobenzene; diphenylguanidine; and combinations thereof.

[0108] In certain embodiments, the cross-linking co-agent may be selected from the group consisting of TRIM, TAIC, TAC, TAP, vinyl cyclic siloxane, and combinations thereof.

[0109] Additive components

[0110] The compositions of the present disclosure may include one or more additives. Therefore, the curable compositions and cross-linked polymer compositions of the present disclosure may include (E) additive components. Suitable additives that may include additive components include, but are not limited to, metal oxides, antioxidants, fillers, UV stabilizers, flame retardants, plasticizers or oils, colorants or pigments, tackifiers, reinforcing agents, fatty acids and their salts, flame retardant additives, scorch inhibitors, stabilizers, foaming agents, lubricants, processing aids, extrusion aids, nucleating agents, scavengers, waxes, curing additives, accelerators, and combinations thereof.

[0111] Metal oxides include, but are not limited to, silicon oxide, calcium oxide, zinc oxide, iron oxide, titanium oxide, and aluminum oxide. Fillers include, but are not limited to, carbon black; aluminum silicate, magnesium silicate, calcium silicate, sodium silicate, potassium silicate, and mixtures thereof; calcium carbonate, magnesium carbonate, and mixtures thereof; calcium sulfate, barium sulfate, and lead sulfate; aluminum oxide trihydrate; magnesium hydroxide; phenol-formaldehyde, polystyrene, and poly(α-methyl)-styrene resins, natural fibers, synthetic fibers, and the like.

[0112] Plasticizers or oils include, but are not limited to, petroleum oils, such as aromatic and naphthenic oils; polyalkylbenzene oils; organic acid monoesters, such as alkyl and alkoxyalkyl oleates and stearates; organic acid diesters, such as dialkyl, dialkoxyalkyl, and alkylaryl phthalates, terephthalates, sebacates, adipates, and glutarates; glycol diesters, such as tri-, tetra-, and polyethylene glycol dialkanoates; trialkyl trimellitates; trialkyl, trialkoxyalkyl, alkyldiaryl, and triaryl phosphates; chlorinated paraffin oils; coumarone-indene resins; pine tar oil; vegetable oils, such as castor, tall, rapeseed, and soybean oils and esters and epoxidized derivatives thereof; and the like.

[0113] Antioxidants and antiozonants include, but are not limited to, hindered phenols, bisphenols, and thiobisphenols; substituted hydroquinones; tris(alkylphenyl)phosphites; dialkylthiodipropionates; phenylnaphthylamines; substituted diphenylamines; dialkyl, alkylaryl, and diaryl substituted p-phenylenediamines; monomeric and polymeric dihydroquinolines; 2-(4-hydroxy-3,5-tert-butylanilino)-4,6-bis(octylthio)1,3,5-triazine, hexahydro-1,3,5- Tris-β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl-s-triazine, 2,4,6-tris(n-1,4-dimethylpentylphenylene-diamino)-1,3,5-triazine, tris-(3,5-di-tert-butyl-4-hydroxybenzyl)-isocyanurate, nickel dibutyldithiocarbamate, 2-mercaptotolylimidazole and its zinc salt, petroleum wax, 2,2,4-trimethyl-1,2-dihydroquinoline, etc.

[0114] UV stabilizers include, but are not limited to, hindered phenols, phosphites, hindered amine light stabilizers (HALS), UV absorbers, hindered benzoates, and combinations thereof. Suitable UV stabilizers include, but are not limited to, T770 available from TCI; UV 531 available from TCI; Cynergy A400, A430, and R350; Cyasorb UV-3529; Cyasorb UV-3346; Cyasorb UV-3583; Hostavin N30; Univil 4050; Univin 5050; Chimassorb UV-119; Chimassorb 944LD; Tinuvin 622LD; benzophenones, benzotriazoles, triazines, and combinations thereof, such as Tinuvin 328 or Cyasorb UV-1164; and the like.

[0115] In certain embodiments, the (E) additive component comprises a metal oxide and an antioxidant.

[0116] Curable composition

[0117] The present disclosure relates to a curable composition comprising: (A) a polyolefin; (B) diatomaceous earth; (C) a crosslinking agent; (D) a crosslinking coagent; and optionally, (E) an additive component. The (E) additive component may include an antioxidant and a metal oxide.

[0118] The (A) polyolefin may be present in the curable composition in an amount of 30 wt% to 95 wt%, or 40 wt% to 95 wt%, or 50 wt% to 85 wt%, or 55 wt% to 75 wt%, based on the total weight of the curable composition.

[0119] (B) diatomaceous earth may be present in the curable composition in an amount of 0.1 wt % to 55 wt %, or 1 wt % to 50 wt %, or 10 wt % to 40 wt %, or 15 wt % to 35 wt %, or 20 wt % to 35 wt %, based on the total weight of the curable composition.

[0120] The (C) crosslinking agent may be present in the curable composition in an amount of 0.01 wt % to 10 wt %, or 0.1 wt % to 10 wt %, or 0.5 wt % to 8 wt %, or 1 wt % to 5 wt %, or 2 wt % to 4 wt %, based on the total weight of the curable composition.

[0121] The (D) crosslinking aid may be present in the curable composition in an amount of 0.01 wt % to 5 wt %, or 0.05 wt % to 3 wt %, or 0.1 wt % to 1 wt %, based on the total weight of the curable composition.

[0122] The (E) additive component may be present in the curable composition in an amount of 0 wt % to 20 wt %, or 0.01 wt % to 20 wt %, or 0.01 wt % to 15 wt %, or 0.01 wt % to 10 wt %, or 0.1 wt % to 10 wt %, or 1 wt % to 10 wt %, or 1 wt % to 8 wt %, or 2 wt % to 6 wt %, based on the total weight of the curable composition.

[0123] In certain embodiments, the ratio of (A) polyolefin to (B) diatomaceous earth in the curable composition is from 100:5 to 100:120 or from 100:20 to 100:80, based on the total weight of (A) polyolefin and (B) diatomaceous earth.

[0124] Polyolefins can be blended with one or more polymers. Thus, the curable compositions of the present disclosure (and crosslinked polymer compositions comprising the reaction products of the curable compositions) can also comprise one or more polymers, including but not limited to unsaturated polyolefins (another EPDM, polybutadiene, etc.), saturated polyolefins (PE, PP, ethylene / α-olefin interpolymers, propylene / α-olefin interpolymers, olefin block copolymers, etc.), other elastomers (SBC, PVC, EVA, etc.), and other engineering thermoplastics (styrenes, polyamides, polyesters, etc.).

[0125] In certain embodiments, the polyolefin is not blended with other polymers.In certain embodiments, the curable composition is absent (or does not include) any polymer other than (A) the polyolefin.

[0126] The curable composition of the present disclosure can be cured to form a crosslinked polymer composition.The crosslinked polymer composition of the present disclosure is the reaction product of the curable composition.

[0127] The curable composition or cross-linked polymer composition according to the methods disclosed herein or similar methods can have the following properties, wherein the volume resistivity is at room temperature. In certain embodiments, the volume resistivity of the curable composition or the cross-linked polymer composition is greater than 1.0E+15 ohm.cm, or greater than or equal to 3.0E+15 ohm.cm, or greater than or equal to 5.0E+15 ohm.cm, or greater than or equal to 7.0E+15 ohm.cm, or greater than or equal to 1.0E+16 ohm.cm, or greater than or equal to 2.0E+16 ohm.cm, or greater than or equal to 4.0E+16 ohm.cm, or greater than or equal to 5.0E+16 ohm.cm, or greater than or equal to 7.0E+16 ohm.cm, or greater than or equal to 1.0E+17 ohm.cm, or greater than or equal to 5.0E+17 ohm.cm, or greater than or equal to 1.0E+18 ohm.cm, or greater than or equal to 1.0E+19 ohm.cm.

[0128] In certain embodiments, the volume resistivity of the curable composition or the cross-linked polymer composition is greater than 1.0E+15 ohm.cm to 1.0E+19 ohm.cm, or greater than 1.0E+15 ohm.cm to 5.0E+18 ohm.cm, or greater than 1.0E+15 ohm.cm to 1.0E+18 ohm.cm, or greater than 1.0E+15 ohm.cm to 5.0E+17 ohm.cm, or greater than 3.0E+15 ohm.cm to 5.0E+17 ohm.cm, or greater than 3.0E+15 ohm.cm to 2.0E+17 ohm.cm.

[0129] Each of the curable composition and the crosslinked polymer composition can have any combination of the embodiments described herein.

[0130] Products and Applications

[0131] The curable compositions or cross-linked polymer compositions disclosed herein can be used to prepare articles by any of a variety of conventional methods and equipment. Illustrative methods include, but are not limited to, extrusion, calendaring, compression molding, and other typical thermosetting material forming methods. For example, articles can be prepared by extrusion, extrusion followed by additional heat treatment, low pressure molding, compression molding, and the like.

[0132] Articles prepared using the curable compositions or cross-linked polymer compositions of the present disclosure include, but are not limited to, sheets, films, molded articles, fibers, and extruded parts. Additional articles include, but are not limited to, soft-touch articles, automotive parts, adhesives, pipes, seals, belts, hoses, building profiles, wire and cable sheathing and assemblies, flooring materials, gaskets and profiles, tires and tire components, computer components, building materials, coatings, woodworking, photovoltaic products, and footwear components. One of ordinary skill in the art can readily expand this list without undue experimentation.

[0133] According to the methods disclosed herein and similar methods, articles may have the following VR properties. In certain embodiments, the volume resistivity of an article comprising (or made from) a curable composition or a cross-linked polymer composition is greater than 1.0E+15 ohm.cm, or greater than or equal to 3.0E+15 ohm.cm, or greater than or equal to 3.45E+15 ohm.cm, or greater than or equal to 5.0E+15 ohm.cm, or greater than or equal to 7.0E+15 ohm.cm, or greater than or equal to 1.0E+16 ohm.cm, or greater than or equal to 2.0E+16 ohm.cm, or greater than or equal to 1.0E+16 ohm.cm. Greater than or equal to 4.0E+16ohm.cm, or greater than or equal to 5.0E+16ohm.cm, or greater than or equal to 7.0E+16ohm.cm, or greater than or equal to 1.0E+17ohm.cm, or greater than or equal to 1.25E+17ohm.cm, or greater than or equal to 5.0E+17ohm.cm, or greater than or equal to 1.0E+18ohm.cm, or greater than or equal to 5.0E+18ohm.cm, or greater than or equal to 1.0E+19ohm.cm.

[0134] In certain embodiments, the volume resistivity of an article comprising (or made from) the curable composition or the cross-linked polymer composition is greater than 1.0E+15 ohm.cm to 1.0E+19 ohm.cm, or greater than 1.0E+15 ohm.cm to 5.0E+18 ohm.cm, or greater than 1.0E+15 ohm.cm to 1.0E+18 ohm.cm, or greater than 1.0E+15 ohm.cm to 5.0E+17 ohm.cm, or greater than 3.0E+15 ohm.cm to 5.0E+17 ohm.cm, or greater than 3.0E+15 ohm.cm to 2.0E+17 ohm.cm.

[0135] An article comprising (or made from) the curable composition or crosslinked polymer composition can be any combination of the embodiments disclosed herein.

[0136] Specific embodiments of the present disclosure include but are not limited to the following:

[0137] 1. A curable composition comprising: (A) a polyolefin; (B) diatomaceous earth; (C) a crosslinking agent; (D) a crosslinking aid; and optionally, (E) an additive component comprising a metal oxide and an antioxidant.

[0138] 2. The curable composition according to embodiment 1, comprising:

[0139] (A) 30 wt % to 95 wt %, or 40 wt % to 95 wt %, or 50 wt % to 85 wt %, or 55 wt % to 75 wt % of a polyolefin, based on the total weight of the curable composition;

[0140] (B) 0.1 wt% to 55 wt% or 1 wt% to 50 wt%, or 10 wt% to 40 wt% or 15 wt% to 35 wt%, or 20 wt% to 35 wt% of diatomaceous earth, based on the total weight of the curable composition;

[0141] (C) 0.01 wt % to 10 wt % or 0.1 wt % to 10 wt %, or 0.5 wt % to 8 wt %, or 1 wt % to 5 wt % or 2 wt % to 4 wt % of a crosslinker, based on the total weight of the curable composition;

[0142] (D) 0.01 wt % to 5 wt %, or 0.05 wt % to 3 wt %, or 0.1 wt % to 1 wt % of a crosslinking aid, based on the total weight of the curable composition; and

[0143] (E) 0 wt % to 20 wt %, or 0.01 wt % to 20 wt %, or 0.01 wt % to 15 wt %, or 0.01 wt % to 10 wt %, or 0.1 wt % to 10 wt %, or 1 wt % to 10 wt %, or 1 wt % to 8 wt %, or 2 wt % to 6 wt % of additive components, based on the total weight of the curable composition.

[0144] 3. The curable composition of embodiment 1 or 2, wherein the polyolefin is selected from the group consisting of ethylene / α-olefin / diene interpolymers, ethylene / α-olefin copolymers, propylene / α-olefin copolymers, and ethylene / α-olefin multi-block interpolymers.

[0145] 4. The curable composition of any preceding embodiment, wherein the α-olefin is selected from the group consisting of ethylene, propylene, 1-butene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, and 1-octadecene.

[0146] 5. The curable composition of any preceding embodiment, wherein the polyolefin is an ethylene / α-olefin / diene interpolymer.

[0147] 6. The curable composition of any preceding embodiment, wherein the polyolefin is an ethylene / propylene / diene interpolymer.

[0148] 7. The curable composition of any preceding embodiment, wherein the polyolefin is an ethylene / propylene / ENB interpolymer.

[0149] 8. The curable composition of any preceding embodiment, wherein the polyolefin comprises vanadium in an amount of less than or equal to 0.4 ppm or less than or equal to 0.3 ppm.

[0150] 9. The curable composition of any preceding embodiment, wherein the polyolefin comprises a Group 4 metal in an amount greater than or equal to 0.3 ppm, or greater than or equal to 0.4 ppm, or greater than or equal to 0.5 ppm, or greater than or equal to 0.6 ppm.

[0151] 10. The curable composition of any preceding embodiment, wherein the polyolefin comprises titanium in an amount greater than or equal to 0.3 ppm, or greater than or equal to 0.4 ppm, or greater than or equal to 0.5 ppm, or greater than or equal to 0.6 ppm.

[0152] 11. The curable composition of any preceding embodiment, wherein the polyolefin comprises zirconium in an amount greater than or equal to 0.3 ppm, or greater than or equal to 0.4 ppm, or greater than or equal to 0.5 ppm, or greater than or equal to 0.6 ppm.

[0153] 12. The curable composition of any preceding embodiment, wherein the polyolefin comprises hafnium in an amount greater than or equal to 0.3 ppm, or greater than or equal to 0.4 ppm, or greater than or equal to 0.5 ppm, or greater than or equal to 0.6 ppm.

[0154] 13. The curable composition of any preceding embodiment, wherein the polyolefin comprises titanium, zirconium, and / or hafnium in an amount greater than or equal to 0.3 ppm, or greater than or equal to 0.4 ppm, or greater than or equal to 0.5 ppm, or greater than or equal to 0.6 ppm.

[0155] 14. The curable composition of any preceding embodiment, wherein the polyolefin has a Mooney viscosity (ML 1+4 at 125°C) of greater than 0 to 100 MU, or 5 to 100 MU, or 15 to 100 MU, or 15 to 99 MU, or 15 to 90 MU, or 15 to 80 MU, or 15 to 70 MU, or 15 to 60 MU, or 15 to 50 MU, or 18 to 45 MU, or 18 to 40 MU, according to ASTM D1646.

[0156] 15. The curable composition of any preceding embodiment, wherein the ethylene / α-olefin / diene interpolymer has a density according to ASTM D792, Method B, from 0.850 g / cc to 0.920 g / cc, or from 0.860 g / cc to 0.910 g / cc, or from 0.860 g / cc to 0.900 g / cc, or from 0.860 g / cc to 0.890 g / cc, or from 0.860 g / cc to 0.880 g / cc, or from 0.870 to 0.880 g / cc.

[0157] 16. The curable composition of any preceding embodiment, wherein the polyolefin comprises 40 wt% to 80 wt%, or 50 wt% to 80 wt%, or 55 wt% to 70 wt% polymerized ethylene.

[0158] 17. The curable composition of any preceding embodiment wherein the polyolefin comprises zero to 10 wt%, or 0.5 wt% to 9 wt%, or 0.5 wt% to 8.5 wt% polymerized diene.

[0159] 18. The curable composition of any preceding embodiment wherein the polyolefin has a molecular weight distribution (MWD or Mw / Mn) of 1 to 7, or 1 to 5, or 1.5 to 5, or 2 to 4.

[0160] 19. The curable composition of any preceding embodiment, wherein the diatomaceous earth is classic Neuburg diatomaceous earth.

[0161] 20. The curable composition of embodiment 19, wherein the diatomaceous earth has a particle size distribution (D50) of 1.5 to 4.

[0162] 21. The curable composition of any preceding embodiment wherein the crosslinker is an organic peroxide.

[0163] 22. The curable composition of embodiment 21, wherein the organic peroxide is selected from the group consisting of di-2-tert-butylperoxyisopropylbenzene, tert-butylperoxy-2-ethylhexyl carbonate, dicumyl peroxide, lauryl peroxide, benzoyl peroxide, tert-butyl perbenzoate, di(tert-butyl peroxide), cumene hydroperoxide, 2,5-dimethyl-2,5-di(tert-butyl-peroxy)hexyne-3, 2,-5-dimethyl-2,5-di(tert-butylperoxy)hexane, tert-butyl hydroperoxide, isopropyl percarbonate, α,α′-bis(tert-butylperoxy)diisopropylbenzene, 1,1-bis(tert-butylperoxy)-3,5,5-trimethylcyclohexane, 2,5-dimethyl-2,5-dihydroxyperoxide, tert-butylcumyl peroxide, α,α′-bis(tert-butylperoxy)-p-diisopropylbenzene, and combinations thereof.

[0164] 23. The curable composition of any preceding embodiment, wherein the crosslinking aid is selected from the group consisting of triallyl cyanurate, triaryl cyanurate, triallyl phosphate, trimethylolpropane trimethacrylate, and combinations thereof.

[0165] 24. The curable composition of any preceding embodiment, wherein the additive component comprises a metal oxide and an antioxidant.

[0166] 25. The curable composition of any preceding embodiment, wherein the volume resistivity of the curable composition is greater than 1.0E+15 ohm.cm, or greater than or equal to 3.0E+15 ohm.cm, or greater than or equal to 5.0E+15 ohm.cm, or greater than or equal to 7.0E+15 ohm.cm, or greater than or equal to 1.0E+16 ohm.cm, or greater than or equal to 2.0E+16 ohm.cm, or greater than or equal to 4.0E+16 ohm.cm, or greater than or equal to 5.0E+16 ohm.cm, or greater than or equal to 7.0E+16 ohm.cm, or greater than or equal to 1.0E+17 ohm.cm, or greater than or equal to 5.0E+17 ohm.cm, or greater than or equal to 1.0E+18 ohm.cm, or greater than or equal to 5.0E+18 ohm.cm, or greater than or equal to 1.0E+19 ohm.cm.

[0167] 26. The curable composition of any preceding embodiment, wherein the volume resistivity of the curable composition is greater than 1.0E+15 ohm.cm to 1.0E+19 ohm.cm, or greater than 1.0E+15 ohm.cm to 5.0E+18 ohm.cm, or greater than 1.0E+15 ohm.cm to 1.0E+18 ohm.cm, or greater than 1.0E+15 ohm.cm to 5.0E+17 ohm.cm, or greater than 3.0E+15 ohm.cm to 5.0E+17 ohm.cm, or greater than or equal to 3.0E+15 ohm.cm to 3.0E+17 ohm.cm, or greater than or equal to 3.0E+15 ohm.cm to 2.0E+17 ohm.cm.

[0168] 27. A cross-linked polymer composition comprising the curable composition of any preceding embodiment.

[0169] 28. A crosslinked polymer composition which is the reaction product of the curable composition of any one of embodiments 1 to 26.

[0170] 29. A crosslinked polymer composition comprising the reaction product of the curable composition of any one of embodiments 1 to 26.

[0171] 30. The crosslinked polymer composition of any of embodiments 27 to 29, wherein the crosslinked polymer composition has a volume resistivity greater than 1.0E+15 ohm.cm, or greater than or equal to 3.0E+15 ohm.cm, or greater than or equal to 5.0E+15 ohm.cm, or greater than or equal to 7.0E+15 ohm.cm, or greater than or equal to 1.0E+16 ohm.cm, or greater than or equal to 2.0E+16 ohm.cm, or greater than or equal to 4.0E+16 ohm.cm, or greater than or equal to 5.0E+16 ohm.cm, or greater than or equal to 7.0E+16 ohm.cm, or greater than or equal to 1.0E+17 ohm.cm, or greater than or equal to 5.0E+17 ohm.cm, or greater than or equal to 1.0E+18 ohm.cm, or greater than or equal to 5.0E+18 ohm.cm, or greater than or equal to 1.0E+19 ohm.cm.

[0172] 31. The cross-linked polymer composition of any of embodiments 27 to 30, wherein the cross-linked polymer composition has a volume resistivity of greater than 1.0E+15 ohm.cm to 1.0E+19 ohm.cm, or greater than 1.0E+15 ohm.cm to 5.0E+18 ohm.cm, or greater than 1.0E+15 ohm.cm to 1.0E+18 ohm.cm, or greater than 1.0E+15 ohm.cm to 5.0E+17 ohm.cm, or greater than 3.0E+15 ohm.cm to 5.0E+17 ohm.cm, or greater than or equal to 3.0E+15 ohm.cm to 3.0E+17 ohm.cm, or greater than or equal to 3.0E+15 ohm.cm to 2.0E+17 ohm.cm.

[0173] 32. An article comprising the curable composition of any one of embodiments 1 to 26.

[0174] 33. An article made from the curable composition of any one of embodiments 1 to 26.

[0175] 34. An article comprising the crosslinked polymer composition of any one of embodiments 27 to 31.

[0176] 35. An article made from the crosslinked polymer composition of any one of embodiments 27 to 31.

[0177] 36. The article of any of embodiments 31 to 35, wherein the volume resistivity of the article is greater than 1.0E+15 ohm.cm, or greater than or equal to 3.0E+15 ohm.cm, or greater than or equal to 5.0E+15 ohm.cm, or greater than or equal to 7.0E+15 ohm.cm, or greater than or equal to 1.0E+16 ohm.cm, or greater than or equal to 2.0E+16 ohm.cm, or greater than or equal to 4.0E+16 ohm.cm, or greater than or equal to 5.0E+16 ohm.cm, or greater than or equal to 7.0E+16 ohm.cm, or greater than or equal to 1.0E+17 ohm.cm, or greater than or equal to 5.0E+17 ohm.cm, or greater than or equal to 1.0E+18 ohm.cm, or greater than or equal to 5.0E+18 ohm.cm, or greater than or equal to 1.0E+19 ohm.cm.

[0178] 37. The article of any of Embodiments 31 to 36, wherein the volume resistivity of the article is greater than 1.0E+15 ohm.cm to 1.0E+19 ohm.cm, or greater than 1.0E+15 ohm.cm to 5.0E+18 ohm.cm, or greater than 1.0E+15 ohm.cm to 1.0E+18 ohm.cm, or greater than 1.0E+15 ohm.cm to 5.0E+17 ohm.cm, or greater than 3.0E+15 ohm.cm to 5.0E+17 ohm.cm, or greater than or equal to 3.0E+15 ohm.cm to 3.0E+17 ohm.cm, or greater than or equal to 3.0E+15 ohm.cm to 2.0E+17 ohm.cm.

[0179] 38. The article of any of embodiments 31 to 37, wherein the article is a film.

[0180] Examples

[0181] Material

[0182] The materials used in the following examples are described below.

[0183] NORDEL TM 3720P ("EPDM 1"): an ethylene propylene diene interpolymer (made via a non-ZN catalyst) commercially available from The Dow Chemical Company: density 0.880 g / cc (ASTM D792); Mooney viscosity (ML 1+4 at 125°C) 20 MU (ASTM D1646); ethylene content 70 wt% (ASTM D3900); and ENB content 0.6 wt% (ASTM D6047).

[0184] NORDEL TM 3722P ("EPDM 2"): an ethylene propylene diene interpolymer (made via a non-ZN catalyst) commercially available from The Dow Chemical Company: density 0.880 g / cc (ASTM D792); Mooney viscosity (ML 1+4 at 125°C) 18 MU (ASTM D1646); ethylene content 71 wt% (ASTM D3900); and ENB content 0.5 wt% (ASTM D6047).

[0185] NORDEL TM4725P ("EPDM 3"): an ethylene propylene diene interpolymer (made via a non-ZN catalyst) commercially available from The Dow Chemical Company: density 0.880 g / cc (ASTM D792); Mooney viscosity (ML 1+4 at 125°C) 25 MU (ASTM D1646); ethylene content 70 wt% (ASTM D3900); and ENB content 4.9 wt% (ASTM D6047).

[0186] EPT TM 2060M ("EPDM 4"): ethylene propylene diene interpolymer available from Mitsui Chemicals (made via a non-ZN catalyst): Mooney viscosity (ML 1+4 at 125°C) of 40 MU (ASTM D1646); ethylene content of 55 wt% (ASTM D3900); and ENB content of 2.3 wt% (ASTM D6047).

[0187] 210 ("EPDM A"): a Ziegler-Natta catalyzed ethylene propylene diene interpolymer available from Kumho Polychem: density 0.860 g / cc (ASTM D792); Mooney viscosity (ML 1+4 at 125°C) 23 MU (ASTM D1646); ethylene content 65 wt% (ASTM D3900); and ENB content 5.7% (ASTM D6047).

[0188] Vistalon TM 2504 ("EPDM B"): a Ziegler-Natta catalyzed ethylene propylene diene interpolymer available from ExxonMobil Chemical Company: Mooney viscosity (ML 1+4 at 125°C) of 25 MU (ASTM D1646); ethylene content of 58 wt% (ASTM D3900); and ENB content of 4.7 wt% (ASTM D6047).

[0189] F40P ("peroxide"): di-2-tert-butylperoxyisopropylbenzene (40% active content in calcium carbonate) available from Arkema.

[0190] SR 350NS ("adjuvant"): trimethylolpropane trimethacrylate available from Sartomer Arkema Group.

[0191] Sillitin N85 ("Diatomaceous Earth 1"): Classic Neuburg diatomaceous earth available from Hofmann Minerals, Inc. Natural combination of fine-grained Neuburg silica and layered kaolinite: a loose mixture that cannot be separated by physical means; D50 = 4.0 μm.

[0192] Sillitin Z86 ("Diatomaceous Earth 2"): Classic Neuburg diatomaceous earth available from Hofmann Minerals, Inc. Natural combination of fine-grained Neuburg silica and layered kaolinite: a loose mixture that cannot be separated by physical means; D50 = 1.9 μm.

[0193] 622LS ("silicon dioxide"): precipitated silica with a particle size D50 of 4.5 μm available from Evonik Industries AG.

[0194] Resin ("Antioxidant"): polymeric 1,2-dihydro-2,2,4-trimethylquinoline available from Vanderbilt Chemicals, LLC.

[0195] Zinc oxide ("ZnO") was purchased from Sinopharm Chemical Reagent Co., Ltd.

[0196] The VR and residual metal contents of neat resins of EPDMs 1 to 4 and EPDMs A and B were measured according to the methods described herein and are shown in Table 1. "ND" means "not detectable," indicating that the measured values were below the detection limits of the metals (0.3 ppm for Zr, 0.4 ppm for V, and 0.8 ppm for Ti).

[0197] Table 1.

[0198] EPDM 1 EPDM 2 EPDM 3 EPDM 4 EPDM A EPDM B VR at room temperature (ohm.cm) 5.75E+14 1.86E+15 1.30E+14 1.54E+14 2.55E+17 9.52E+16 Vanadium (ppm) ND ND ND ND 13.6 1.93 Zirconium (ppm) ND 0.522 0.364 ND ND ND

[0199] Sample preparation

[0200] Each of the comparative examples (CE1 to CE7) and inventive examples (IE1 to IE7) was prepared as described below and according to the formulations of Tables 2 and 3.

[0201] EPDM was fed into a Brabender mixer at a set temperature of 100°C and a rotor speed of 30 rpm. After approximately 2 minutes, the EPDM was uniformly heated / melted. All other components, including diatomaceous earth, were weighed and then gradually added to the chamber. A further 3 minutes at 50 rpm were used to disperse the filler and various other additives. The final mix was run for 6 minutes at the set temperature and a rotor speed of 40 rpm, using a lower rotor speed to control the rapid increase in melt temperature and avoid scorching. The compound was collected and pressed into flat cakes for later use.

[0202] Preparation of cured films: The compound mixed from Brabender was compression molded into 0.5 mm films. The samples were pre-compressed and then degassed before a T90+6 minute press process at 180°C to ensure complete curing of the samples before ramping down to room temperature.

[0203] Preparation of uncured film: The compound mixed from Brabender was preheated at 120° C. for 5 minutes and then degassed, followed by a pressing process at 120° C. for 1 minute and then ramped down to room temperature. The film thickness was also 0.5 mm.

[0204] VR and cure characteristics were measured and are shown in Tables 2 and 3.

[0205] Table 2.

[0206]

[0207] Table 3:

[0208]

[0209] As seen in Table 1, the ZN-catalyzed polyolefins (EPDM A and B) have much higher VR (2-3 orders of magnitude) relative to the polyolefins made with non-ZN catalysts (EPDM 1-4).

[0210] As seen in Inventive Examples IE1 to IE7, the compositions of the present disclosure that include diatomaceous earth unexpectedly and surprisingly significantly improve VR. In fact, in each of Inventive Examples 1-7, VR improved by more than one order of magnitude, and even by as much as two orders of magnitude. In contrast, as seen in CE1 to CE5, the addition of the same diatomaceous earth to ZN-catalyzed polyolefins primarily reduced the VR of the polyolefin compositions. Furthermore, as seen in Examples CE6 and CE7, the addition of silica was shown to reduce the VR of the polyolefin compositions.

[0211] Furthermore, the curing characteristics of Examples 1-7 of the present invention demonstrate that the addition of diatomaceous earth to improve VR does not negatively impact the curing characteristics. In summary, the compositions of the present disclosure can significantly improve the electrical properties (higher VR) of polyolefins, such as non-ZN-catalyzed EPDM, without compromising the curing characteristics, thereby enabling the use of such polyolefins in electrical applications. Furthermore, such improvements cannot be achieved with ZN-catalyzed polyolefins that also incorporate diatomaceous earth.

Claims

1. A curable composition comprising: 50 wt% to 95 wt% of (A) a non-Ziegler-Natta catalyzed polyolefin having a Mooney viscosity ML 1+4 of 5 MU to 50 MU at 125°C according to ASTM D1646; 20 wt% to 50 wt% of (B) diatomaceous earth; (C) a crosslinking agent; (D) a crosslinking coagent; and 0 wt% to 10 wt% of (E) an additive component, wherein the (A) non-Ziegler-Natta catalyzed polyolefin is an ethylene / propylene / ENB interpolymer, wherein the sum of the weight percentages of all components in the curable composition is 100 wt%.

2. The curable composition of claim 1, wherein the additive component comprises a metal oxide and an antioxidant.

3. The curable composition according to claim 1, comprising, based on the total weight of the curable composition: 50 wt% to 85 wt% of said non-Ziegler-Natta catalyzed polyolefin; 20 wt% to 40 wt% of the diatomaceous earth; 0.01 wt % to 8 wt % of the cross-linking agent; 0.01 wt% to 5 wt% of the crosslinking aid; and 1 wt% to 8 wt% of said additive component, The total weight percentage of all components in the curable composition is 100 wt %.

4. The curable composition of any one of claims 1 to 3, wherein the non-Ziegler-Natta catalyzed polyolefin comprises vanadium in an amount of 0.4 ppm or less.

5. The curable composition of any one of claims 1 to 3, wherein the non-Ziegler-Natta catalyzed polyolefin comprises a Group 4 metal in an amount of 0.3 ppm or greater.

6. The curable composition of any one of claims 1 to 3, wherein the non-Ziegler-Natta catalyzed polyolefin has a Mooney viscosity ML 1+4 at 125°C according to ASTM D1646 of 10 MU to 40 MU.

7. The curable composition of any one of claims 1 to 3, wherein the volume resistivity of the curable composition is greater than 3.0E+15 ohm.cm.

8. A cross-linked polymer composition comprising the reaction product of the curable composition according to any one of claims 1 to 7.

9. The cross-linked polymer composition of claim 8, wherein the cross-linked polymer composition has a volume resistivity greater than 3.0E+15 ohm.cm.

10. An article comprising the curable composition according to any one of claims 1 to 7.

11. An article comprising the cross-linked polymer composition according to claim 8 or 9.

12. The article of claim 10 or 11, wherein the volume resistivity of the article is greater than 3.0E+15 ohm.cm.

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