Polymer composition with reduced shrinkage

Abstract

A polymer composition includes from 20 wt% to 70 wt%, based on the total weight of the polymer composition, of a first ethylene-based polymer, where the first ethylene-based polymer has a density from 0.93 g / cc to 0.970 g / cc, as measured according to ASTM D792; from 5 wt% to 35 wt%, based on the total weight of the polymer composition, of a second ethylene-based polymer, where the second ethylene-based polymer has a density from 0.885 g / cc to 0.93 g / cc, as measured according to ASTM D792; and from 1 wt% to 55 wt%, based on the total weight of the polymer composition, of a polymer shrink additive, where the polymer shrink additive has a melting peak temperature or a glass transition temperature greater than the melting peak temperature of the first ethylene-based polymer and the second ethylene-based polymer.

Description

Background Technology Technical Field

[0001] This disclosure relates to polymer compositions, and more particularly to polymer compositions with reduced shrinkage. Background Technology

[0002] With the rise of 5G networks, the demand for broadband connecting data centers, office spaces, and homes is constantly increasing. Because fiber optics offer the highest data transmission efficiency and reliability, the broadband industry is shifting towards using fiber optics to replace traditional copper wires. Accompanying this shift in fiber optic usage is fiber densification, which involves increasing the number of optical fibers present in data cables.

[0003] To accommodate more optical fibers per cable, the sheath on each fiber is typically made thinner. This reduction in fiber sheath thickness has previously been associated with increased sheath shrinkage. In some polymer applications, shrinkage is a desirable quality. For example, U.S. Patent No. 11,441,023 discloses a shrink-wrapped polymer composition comprising a cyclic olefin copolymer and a polyethylene-based material. See also U.S. Patent No. 11,541,646, which explains that “large shrinkage potential can be obtained, for example, by polymer compounds such as cyclic olefin copolymers…”. In other applications, shrinkage is undesirable. Polypropylene is known to have low shrinkage (e.g., about 0.5% or less), but a high weight percentage loading (e.g., greater than 50% by volume) in the polymer composition is often required to achieve shrinkage properties close to those of polypropylene.

[0004] Compared to other polymer applications, shrinkage of the polymer sheath on optical fibers is undesirable. When exposed to mechanical stress, optical fibers may suffer from data transmission quality loss and / or signal attenuation. For example, shrinkage of the sheath positioned on and around the optical fiber can cause mechanical stress that leads to signal attenuation. Shrinkage may occur shortly after extrusion (i.e., “post-extrusion shrinkage”) and when the sheath undergoes temperature cycling during its use (i.e., “cyclic shrinkage”). Typical cyclic shrinkage values ​​are approximately 2.5% or greater. To reduce stress in the optical fiber, the polymer composition forming the sheath should exhibit a post-extrusion shrinkage value of 0.5% or less, as measured according to the PES test provided below. Furthermore, the polymer composition should exhibit cyclic shrinkage of 2.20% or less.

[0005] Given the foregoing, it is surprising to find a polymer composition that can exhibit post-extrusion shrinkage of 0.5% or less and cyclic shrinkage of 2.20% or less. Summary of the Invention

[0006] The inventors of this application have discovered a polymer composition that can exhibit a post-extrusion shrinkage value of 0.5% or less and a cyclic shrinkage of 2.20% or less.

[0007] This invention relates to the discovery that polymer shrinkage additives containing a melt peak temperature or glass transition temperature higher than that of the olefinic component of the polymer composition can reduce post-extrusion shrinkage and cyclic shrinkage. Unbound by theory, it is believed that during the extrusion of the polymer composition, high shear stress stretches and oriented the polyethylene chains, which are then frozen in place by a water bath. When the polymer composition is subsequently exposed to elevated temperatures during use, the aligned polymer chains acquire sufficient mobility to relax, resulting in macroscopic shrinkage. It is believed that the polymer shrinkage additive functions similarly to a filler that holds different phases within the polymer composition. The different phases of the shrinkage additive resist the relaxation of the polymer chains and thus reduce shrinkage because the higher melt peak temperature or glass transition temperature of the polymer shrinkage additive means that its polymer chains are immobile, while the chains of the olefinic component are mobile.

[0008] According to a first feature of this disclosure, the polymer composition comprises 20% to 70% by weight of a first ethylene-based polymer based on the total weight of the polymer composition, wherein the first ethylene-based polymer has a density of 0.93 g / cc to 0.970 g / cc, as measured according to ASTM D792; 5% to 35% by weight of a second ethylene-based polymer based on the total weight of the polymer composition, wherein the second ethylene-based polymer has a density of 0.885 g / cc to 0.93 g / cc, as measured according to ASTM D792; and 1% to 55% by weight of a polymer shrinkage additive based on the total weight of the polymer composition, wherein the peak melting temperature or glass transition temperature of the polymer shrinkage additive is greater than the peak melting temperatures of the first ethylene-based polymer and the second ethylene-based polymer.

[0009] According to a second feature of this disclosure, the polymer composition has any one of features (i) to (vi): (i) the first ethylene-based polymer is bimodal; (ii) the first ethylene-based polymer has a density of 0.950 g / cc to 0.970 g / cc, as measured according to ASTM D792; (iii) the first ethylene-based polymer has a melting peak temperature of 125°C to 200°C, as measured according to differential scanning calorimetry; (iv) the first ethylene-based polymer is a copolymer of ethylene and hexene; (v) the first ethylene-based polymer has a melt index of 1.0 g / 10 min to 2.5 g / 10 min, as measured according to ASTM D1238; and (vi) any combination of two or more of features (i) to (iv).

[0010] According to a third feature of this disclosure, the polymer composition has any one of features (i) to (vi): (i) the second ethylene-based polymer is linear or substantially linear; (ii) the second ethylene-based polymer has a density of 0.91 g / cc to 0.93 g / cc, as measured according to ASTM D792; (iii) the second ethylene-based polymer has a melting peak temperature of 110°C to 130°C, as measured according to differential scanning calorimetry; (iv) the second ethylene-based polymer is a copolymer of ethylene and butene; (v) the second ethylene-based polymer has a melt index of 0.3 g / 10 min to 1.0 g / 10 min, as measured according to ASTM D1238; and (vi) any combination of two or more of features (i) to (v).

[0011] According to the fourth feature of this disclosure, the polymer composition, wherein the polymer shrinkage additive is selected from any of the following (i) to (iii): (i) cyclic olefin copolymers; (ii) polypropylene-based polymers; and (iii) combinations of (i) and (ii).

[0012] According to the fifth feature of this disclosure, the polymer shrinkage additive is a cyclic polyolefin copolymer and has any of the features (i) to (v): (i) the cyclic polyolefin copolymer is a copolymer of ethylene and norbornene; (ii) the cyclic polyolefin copolymer is a copolymer of ethylene and 50% to 90% by weight of cyclic comonomers based on the total weight of the cyclic polyolefin; (iii) the cyclic polyolefin copolymer has a glass transition temperature of 135°C to 200°C, as measured by differential scanning calorimetry; (iv) the cyclic polyolefin copolymer has a density of 0.95 g / cc to 1.10 g / cc, as measured according to ASTM D792; and (v) any combination of two or more of the features (i) to (iv).

[0013] According to the sixth feature of this disclosure, the polymer shrinkage additive is a polypropylene-based polymer and has any of the features (i) to (iii): (i) the polypropylene-based polymer is 90% by weight or more of propylene based on the total weight of the polypropylene-based polymer; (ii) the polypropylene-based polymer has a melt peak temperature of 135°C to 200°C, as measured by differential scanning calorimetry; (iii) the polypropylene-based polymer has a density of 0.89 g / cc to 0.92 g / cc, as measured by ASTM D792; and (iv) any combination of two or more of the features (i) to (iii).

[0014] According to the seventh feature of this disclosure, the polymer composition further comprises 0.5% to 15% by weight of a compatibilizer based on the total weight of the polymer composition.

[0015] According to the eighth feature of this disclosure, the polymer composition comprises 20% to 50% by weight of a polymer shrinkage additive based on the total weight of the polymer composition.

[0016] According to the ninth feature of this disclosure, the polymer composition has any one of features (i) to (vi): (i) post-extrusion shrinkage of 0.50 or less, as measured according to the PES test; (ii) cyclic shrinkage of 2.2 or less, as measured according to the CS test; (iii) density of 0.94 g / cc to 0.98 g / cc, as measured according to ASTM D792; (iv) melt index of 0.5 g / 10 min to 2.0 g / 10 min; (v) ESCR of 2000 hours or longer, as measured according to ASTM D1693-15 in 10% Igepal; and (vi) any combination of any two of (i) to (iv).

[0017] According to the tenth feature of this disclosure, the cable includes a conductor; and a polymer composition positioned around the conductor. Detailed Implementation

[0018] As used herein, the term “and / or” when used in a list of two or more items means that any one of the listed items may be used alone, or any combination of two or more of the listed items may be used. For example, if a composition is described as containing components A, B, and / or C, the composition may contain A alone; contain B alone; contain C alone; contain A and B in combination; contain A and C in combination; contain B and C in combination; or contain A, B, and C in combination.

[0019] Unless otherwise stated, all ranges include the endpoints.

[0020] A test method refers to the most recent test method as of the priority date of this document, unless the date is indicated by a two-digit test method number with a hyphen. References to test methods include references to both the testing association and the test method number. Test method organizations are referenced by one of the following abbreviations: ASTM refers to ASTM International (formerly known as the American Society for Testing and Materials); IEC refers to the International Electrotechnical Commission; EN refers to European Standards; DIN refers to the German Institute for Standardization; and ISO refers to the International Organization for Standardization.

[0021] As used herein, unless otherwise stated, the term weight percentage (“wt%”) means the weight percentage of a component relative to the total weight of the polymer composition.

[0022] The melt index (I2) values ​​in this article refer to those measured according to ASTM method D1238 at 190 degrees Celsius (°C) and 2.16 kilograms (kg) and are provided in grams eluted per ten minutes (“g / 10min”).

[0023] The density values ​​in this document refer to those determined according to ASTM D792 at 23°C and are provided in grams per cubic centimeter (“g / cc”).

[0024] As used herein, the Chemical Abstracts Service Registry Number (“CAS#”) refers to a unique numerical identifier recently assigned to a chemical compound by the Chemical Abstracts Service from the priority date of this document.

[0025] polymer composition

[0026] This disclosure relates to polymer compositions. The polymer compositions comprise a first ethylene-based polymer, a second ethylene-based polymer, and a shrinkage additive.

[0027] The polymer composition may exhibit one or more of the following characteristics (i) to (vi): (i) post-extrusion shrinkage of 0.50 or less, as measured according to the PES test; (ii) cyclic shrinkage of 2.20 or less, as measured according to the CS test; (iii) density of 0.94 g / cc to 0.98 g / cc, as measured according to ASTM D792; (iv) melt index (I2) of 0.5 g / 10 min to 2.0 g / 10 min; (v) environmental stress cracking resistance (“ESCR”) of 2000 hours or longer, as measured according to ASTM D1693-15 in 10% Igepal; and (vi) any combination of two of (i) to (v).

[0028] The polymer composition may exhibit post-extrusion shrinkage of 0.50 or less, as measured by PES testing. For example, the polymer composition may exhibit post-extrusion shrinkage of 0.50 or less, or 0.45 or less, or 0.40 or less, or 0.35 or less, or 0.30 or less, or 0.25 or less, or 0.20 or less, or 0.15 or less, or 0.11 or less, while simultaneously exhibiting post-extrusion shrinkage of 0.10 or greater, or 0.20 or greater, or 0.30 or greater, or 0.40 or greater, as measured by PES testing.

[0029] The polymer composition may exhibit a cycle shrinkage of 2.20 or less, as measured by the CS test. For example, the polymer composition may exhibit a cyclic shrinkage of 2.20 or less, or 2.10 or less, or 2.00 or less, or 1.90 or less, or 1.80 or less, or 1.70 or less, or 1.60 or less, or 1.50 or less, or 1.40 or less, or 1.30 or less, or 1.20 or less, or 1.10 or less, or 1.80 or less, or 1.00 or less, or 0.90 or less, or 0.80 or less, or 0.70 or less, or 0.60 or less, or 0.50 or less, or 0.40 or less, or 0.30 or less, while simultaneously exhibiting a cyclic shrinkage of 0.20 or greater, or 0.50 or greater, or 1.00 or greater, or 1.50 or greater, or 2.00 or greater, as measured by a CS test.

[0030] The polymer composition may exhibit a density from 0.94 g / cc to 0.98 g / cc, as measured according to ASTM D792. For example, the polymer composition may have a density of 0.940 g / cc or greater, or 0.945 g / cc or greater, or 0.950 g / cc or greater, or 0.955 g / cc or greater, or 0.960 g / cc or greater, or 0.965 g / cc or greater, or 0.970 g / cc or greater, or 0.975 g / cc or greater, while simultaneously having a density of 0.980 g / cc or less, or 0.975 g / cc or less, or 0.970 g / cc or less, or 0.965 g / cc or less, or 0.960 g / cc or less, or 0.955 g / cc or less, or 0.950 g / cc or less, or 0.945 g / cc or less, as measured according to ASTM D792.

[0031] The polymer composition may have a melt index (I2) of 0.5 g / 10 min to 2.0 g / 10 min, as measured according to ASTM D1238. For example, the first ethylene-based polymer may have a melt index (I2) of 0.5 g / 10 min or greater, or 0.6 g / 10 min or greater, or 0.7 g / 10 min or greater, or 0.8 g / 10 min or greater, or 0.9 g / 10 min or greater, or 1.0 g / 10 min or greater, or 1.1 g / 10 min or greater, or 1.2 g / 10 min or greater, or 1.3 g / 10 min or greater, or 1.4 g / 10 min or greater, or 1.5 g / 10 min or greater, or 1.6 g / 10 min or greater, or 1.7 g / 10 min or greater, or 1.8 g / 10 min or greater, or 1.9 g / 10 min or greater, while Simultaneously, a melt index (I2) of 2.0 g / 10 min or less, or 1.9 g / 10 min or less, or 1.8 g / 10 min or less, or 1.7 g / 10 min or less, or 1.6 g / 10 min or less, or 1.5 g / 10 min or less, or 1.4 g / 10 min or less, or 1.3 g / 10 min or less, or 1.2 g / 10 min or less, or 1.1 g / 10 min or less, or 1.0 g / 10 min or less, or 0.9 g / 10 min or less, or 0.8 g / 10 min or less, or 0.7 g / 10 min or less, or 0.6 g / 10 min or less, as measured according to ASTM D1238.

[0032] The polymer composition may have an ESCR of 2000 hours or longer, as measured in 10% Igepal according to ASTM D1693-15. For example, the polymer composition may have an ESCR of 2000 hours or longer, or 2500 hours or longer, or 3000 hours or longer, or 3500 hours or longer, or 4000 hours or longer, or 4500 hours or longer, or 5000 hours or longer, as measured in 10% Igepal according to ASTM D1693-15.

[0033] The first ethylene-based polymer

[0034] As described above, the composition may comprise a first ethylene-based polymer. The first ethylene-based polymer may have any of the characteristics (i) to (vi): (i) the first ethylene-based polymer is bimodal; (ii) the first ethylene-based polymer has a density of 0.950 g / cc to 0.970 g / cc, as measured according to ASTM D792; (iii) the first ethylene-based polymer has a melting peak temperature of 125°C to 200°C, as measured according to differential scanning calorimetry; (iv) the first ethylene-based polymer is a copolymer of ethylene and hexene; (v) the first ethylene-based polymer has a melt index of 1.0 g / 10 min to 2.5 g / 10 min, as measured according to ASTM D1238; and (vi) any combination of two or more of the characteristics (i) to (v).

[0035] As used herein, "ethylene-based" polymers are polymers in which more than 50% by weight of the monomers are ethylene, but other comonomers may also be used. Ethylene-based polymers include ethylene and one or more C3-C... 20 α-Olefin comonomers, such as propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, and 1-octene. In a specific example, the first ethylene-based polymer is a copolymer of ethylene and hexene. In another example, the second ethylene-based polymer may be a copolymer of ethylene and butene.

[0036] Ethylene-based polymers may contain 50% or more, 60% or more, 70% or more, 80% or more, 85% or more, 90% or more, or 91% or more, or 92% or more, or 93% or more, or 94% or more, or 95% or more, or 96% or more, or 97% or more, or 97.5% or more, or 98% or more, or 99% or more, while simultaneously, 99.5% or more Less, or 99% by weight or less, or 98% by weight or less, or 97% by weight or less, or 96% by weight or less, or 95% by weight or less, or 94% by weight or less, or 93% by weight or less, or 92% by weight or less, or 91% by weight or less, or 90% by weight or less, or 85% by weight or less, or 80% by weight or less, or 70% by weight or less, or 60% by weight or less ethylene monomer, as measured using nuclear magnetic resonance (NMR) or Fourier transform infrared (FTIR) spectroscopy.

[0037] Other units of ethylene-based polymers can be derived from one or more polymerizable monomers, including but not limited to polar monomers such as unsaturated esters. Unsaturated esters (i.e., polar monomers) can be alkyl acrylates, alkyl methacrylates, or vinyl carboxylate esters. Alkyl groups can have 1 to 8 carbon atoms, or 1 to 4 carbon atoms. Carboxylate ester groups can have 2 to 8 carbon atoms, or 2 to 5 carbon atoms. Examples of acrylates and methacrylates include, but are not limited to, ethyl acrylate, methyl acrylate, methyl methacrylate, tert-butyl acrylate, n-butyl acrylate, n-butyl methacrylate, and 2-ethylhexyl acrylate. Examples of vinyl carboxylate esters include, but are not limited to, vinyl acetate, vinyl propionate, and vinyl butyrate. Ethylene-based polymers may have a polar comonomer content of 40% or less, or 35% or less, or 30% or less, or 25% or less, or 20% or less, 15% or 10% or less, or 5% or less, or 3% or less, or 1% or less, or 0% as measured by nuclear magnetic resonance (NMR) or Fourier transform infrared (FTIR) spectroscopy.

[0038] Ethylene-based polymers can have unimodal or multimodal molecular weight distributions and can be used alone or in combination with one or more other types of ethylene-based polymers (e.g., blends of two or more ethylene-based polymers that differ from each other in monomer composition and content, catalytic preparation method, molecular weight, molecular weight distribution, density, etc.). If blends of ethylene-based polymers are used, the polymers can be blended by any in-reactor or post-reactor method. The term "multimodal polymer" refers to a polymer characterized by having at least two distinct peaks in a gel permeation chromatography (GPC) chromatogram depicting the molecular weight distribution of the composition. Therefore, the general term multimodal polymer includes bimodal polymers having two main fractions: a first fraction, which may be a low molecular weight fraction and / or component; and a second fraction, which may be a high molecular weight fraction and / or component.

[0039] The polymer composition may comprise 20% to 70% by weight of a first ethylene-based polymer based on the total weight of the polymer composition. For example, the polymer composition may comprise 20% or more, or 25% or more, or 30% or more, or 35% or more, or 40% or more, or 45% or more, or 50% or more, or 55% or more, or 60% or more, or 65% or more, while simultaneously comprising 70% or less, or 65% or less, or 60% or less, or 55% or less, or 50% or less, or 45% or less, or 40% or less, or 35% or less, or 30% or less, or 25% or less of a first ethylene-based polymer based on the total weight of the polymer composition.

[0040] The density of the first ethylene-based polymer is 0.93 g / cc to 0.97 g / cc, as measured according to ASTM D792. For example, the density of the first ethylene-based polymer is 0.930 g / cc or greater, or 0.935 g / cc or greater, or 0.940 g / cc or greater, or 0.945 g / cc or greater, or 0.950 g / cc or greater, or 0.955 g / cc or greater, or 0.960 g / cc or greater, or 0.965 g / cc or greater, while simultaneously being 0.970 g / cc or less, or 0.965 g / cc or less, or 0.960 g / cc or less, or 0.955 g / cc or less, or 0.950 g / cc or less, or 0.945 g / cc or less, or 0.940 g / cc or less, or 0.935 g / cc or less, as measured according to ASTM D792. Typically, ethylene-based polymers with a density of 0.94 g / cc to 0.97 g / cc are referred to as "high-density polyethylene" or "HDPE".

[0041] The first ethylene-based polymer has a peak melting temperature of 125°C to 200°C, as measured by differential scanning calorimetry. For example, the first ethylene-based polymer has a peak melting temperature of 125°C or higher, or 130°C or higher, or 135°C or higher, or 140°C or higher, 145°C or higher, or 140°C or higher, 145°C or higher, or 140°C or higher, 145°C or higher, or 140°C or higher, 145°C or higher, or 140°C or higher, 145°C or higher, while simultaneously reaching 200°C or higher. The melting peak temperature is lower, or 195°C or lower, or 190°C or lower, or 185°C or lower, or 180°C or lower, or 175°C or lower, or 170°C or lower, or 165°C or lower, or 160°C or lower, or 155°C or lower, or 150°C or lower, or 145°C or lower, or 140°C or lower, or 135°C or lower, or 130°C or lower, as measured by differential scanning calorimetry.

[0042] The first ethylene-based polymer may have a melt index (I2) of 1.0 g / 10 min to 2.5 g / 10 min, as measured according to ASTM D1238. For example, the first ethylene-based polymer may have a melt index (I2) of 1.0 g / 10 min or greater, or 1.1 g / 10 min or greater, or 1.2 g / 10 min or greater, or 1.3 g / 10 min or greater, or 1.4 g / 10 min or greater, or 1.5 g / 10 min or greater, or 1.6 g / 10 min or greater, or 1.7 g / 10 min or greater, or 1.8 g / 10 min or greater, or 1.9 g / 10 min or greater, or 2.0 g / 10 min or greater, or 2.1 g / 10 min or greater, or 2.2 g / 10 min or greater, or 2.3 g / 10 min or greater, or 2.4 g / 10 min or greater, while Simultaneously, a melt index (I2) of 2.5 g / 10 min or less, or 2.4 g / 10 min or less, or 2.3 g / 10 min or less, or 2.2 g / 10 min or less, or 2.1 g / 10 min or less, or 2.0 g / 10 min or less, or 1.9 g / 10 min or less, or 1.8 g / 10 min or less, or 1.7 g / 10 min or less, or 1.6 g / 10 min or less, or 1.5 g / 10 min or less, or 1.4 g / 10 min or less, or 1.3 g / 10 min or less, or 1.2 g / 10 min or less, or 1.1 g / 10 min or less, as measured according to ASTM D1238.

[0043] Second ethylene-based polymer

[0044] As described above, the composition may comprise a second ethylene-based polymer. The second ethylene-based polymer may have any of the characteristics (i) to (vi): (i) the second ethylene-based polymer is linear or substantially linear; (ii) the second ethylene-based polymer has a density of 0.950 g / cc or less, as measured according to ASTM D792; (iii) the second ethylene-based polymer has a melting peak temperature of 110°C to 130°C, as measured according to differential scanning calorimetry; (iv) the second ethylene-based polymer is a copolymer of ethylene and butene; (v) the second ethylene-based polymer has a melt index of 0.3 g / 10 min to 1.0 g / 10 min; and (vi) any combination of two or more of the characteristics (i) to (v).

[0045] The polymer composition may contain 5% to 35% by weight of a second ethylene-based polymer based on the total weight of the polymer composition. For example, the polymer composition may contain 5% or more, or 10% or more, or 15% or more, or 20% or more, or 25% or more, or 30% or more, based on the total weight of the polymer composition, while simultaneously containing 35% or less, or 30% or less, or 25% or less, or 20% or less, or 15% or less, or 10% or less of a second ethylene-based polymer based on the total weight of the polymer composition.

[0046] The second ethylene-based polymer may have short-chain branching and thus can be classified as linear or substantially linear. As used herein, “substantially linear” means that the bulk polymer is on average replaced by about 0.01 long branches / 1000 total carbons (including main chain and branched carbons) to about 3 long branches / 1000 total carbons, preferably about 0.01 long branches / 1000 total carbons to about 1 long branch / 1000 total carbons, more preferably about 0.05 long branches / 1000 total carbons to about 1 long branch / 1000 total carbons, and especially about 0.3 long branches / 1000 total carbons to about 1 long branch / 1000 total carbons. "Long branched" or "long-chain branched" (LCB) means that the chain length is at least one (1) fewer carbons than the number of carbons in the comonomer, while "short branched" or "short-chain branched" (SCB) means that the chain length is two (2) fewer carbons than the number of carbons in the comonomer. For example, a substantially linear polymer of ethylene / 1-octene has a long branched backbone with a length of at least seven (7) carbons, but it also has short branches with a length of only six (6) carbons, while a substantially linear polymer of ethylene / 1-hexene has a long branched backbone with a length of at least five (5) carbons, but it also has short branches with a length of only four (4) carbons. By using 1312C nuclear magnetic resonance (NMR) spectroscopy can distinguish LCBs from SCBs, and to a limited extent, for example, for ethylene homopolymers, it can be quantified using Randall's method (Rev. Macromol. Chem. Phys.), C29 (2&3). pp. 285-297. However, in practice, existing methods... 13 C10 NMR spectroscopy cannot determine the length of long branches exceeding about six (6) carbon atoms; therefore, this analytical technique cannot distinguish between branches with seven (7) carbon atoms and those with seventy (70) carbon atoms. LCBs can be approximately the same length as the polymer backbone.

[0047] The second ethylene-based polymer has a density of 0.885 g / cc to 0.93 g / cc, as measured according to ASTM D792. For example, the second ethylene-based polymer has a density of 0.885 g / cc or greater, or 0.89 g / cc or greater, or 0.90 g / cc or greater, or 0.91 g / cc or greater, or 0.92 g / cc or greater, while simultaneously having a density of 0.93 g / cc or less, or 0.92 g / cc or less, or 0.91 g / cc or less, or 0.90 g / cc or less, or 0.89 g / cc or less, as measured according to ASTM D792.

[0048] The second ethylene-based polymer has a melting peak temperature of 110°C to 130°C, as measured by differential scanning calorimetry. For example, the second ethylene-based polymer has a melting peak temperature of 110°C or higher, or 112°C or higher, or 114°C or higher, 116°C or higher, or 118°C or higher, 120°C or higher, or 122°C or higher, 124°C or higher, or 126°C or higher, or 128°C or higher, while simultaneously having a melting peak temperature of 130°C or lower, or 128°C or lower, or 126°C or lower, or 124°C or lower, or 122°C or lower, or 120°C or lower, or 118°C or lower, or 116°C or lower, or 114°C or lower, or 112°C or lower, as measured by differential scanning calorimetry.

[0049] The second ethylene-based polymer may have a melt index (I2) of 0.3 g / 10 min to 1.0 g / 10 min, as measured according to ASTM D1238. For example, the second ethylene-based polymer may have a melt index (I2) of 0.3 g / 10 min or greater, or 0.4 g / 10 min or greater, or 0.5 g / 10 min or greater, or 0.6 g / 10 min or greater, or 0.7 g / 10 min or greater, or 0.8 g / 10 min or greater, or 0.9 g / 10 min or greater, while simultaneously having a melt index (I2) of 1.0 g / 10 min or less, or 0.9 g / 10 min or less, or 0.8 g / 10 min or less, or 0.7 g / 10 min or less, or 0.6 g / 10 min or less, or 0.5 g / 10 min or less, or 0.4 g / 10 min or less, or 0.3 g / 10 min or less, or 0.2 g / 10 min or less, as measured according to ASTM D1238.

[0050] Polymer shrinkage additives

[0051] The polymer composition contains a polymer shrinkage additive. The addition of the polymer shrinkage additive causes the polymer composition to exhibit lower post-extrusion shrinkage and lower cyclic shrinkage. According to various examples, the melt peak temperature or glass transition temperature of the polymer shrinkage additive is greater than the melt peak temperature of the first ethylene-based polymer alone or in combination with that of the second ethylene-based polymer.

[0052] The polymer composition comprises 1% to 55% by weight of a polymer shrinkage additive based on the total weight of the polymer composition. For example, the polymer composition comprises 1% or more, or 5% or more, or 10% or more, or 15% or more, or 20% or more, or 25% or more, or 30% or more, or 35% or more, or 40% or more, or 45% or more, or 50% or more, while simultaneously comprising 55% or less, or 50% or less, or 45% or less, or 40% or less, or 35% or less, or 30% or less, or 25% or less, or 20% or less, or 15% or less, or 10% or less, or 5% or less, or 2% or less. In a specific example, the polymer composition comprises 20% to 50% by weight of a polymer shrinkage additive based on the total weight of the polymer composition.

[0053] The polymer shrinkage additive is selected from cyclic polyolefin copolymers, polypropylene-based polymers, and combinations thereof. In an example where the polymer shrinkage additive is a cyclic polyolefin copolymer, the cyclic polyolefin copolymer may have any of the characteristics (i) to (v): (i) the cyclic polyolefin copolymer is a copolymer of ethylene and a cyclic comonomer such as norbornene; (ii) the cyclic polyolefin copolymer is a copolymer of ethylene and 50% to 90% by weight of a cyclic comonomer based on the total weight of the cyclic polyolefin copolymer; (iii) the cyclic polyolefin has a glass transition temperature of 135°C to 200°C, as measured by differential scanning calorimetry; (iv) the cyclic polyolefin copolymer has a density of 0.95 g / cc to 1.10 g / cc, as measured according to ASTM D792; and (v) any combination of two or more of the characteristics (i) to (iv).

[0054] Examples of cyclic polyolefin copolymers are copolymers of olefins and one or more cyclic moieties. For example, a cyclic polyolefin copolymer may comprise an olefin (e.g., ethylene, propylene, butene, hexene, octene, etc.) and cyclic comonomers such as norbornene, cyclopentene, other cyclic comonomers, and combinations thereof. A cyclic polyolefin copolymer may contain 50% or more, 60% or more, 70% or more, 80% or more, 85% or more, and simultaneously 90% or less, or 85% or less, or 80% or less, or 70% or less, or 60% or less of cyclic comonomers, as measured using nuclear magnetic resonance (NMR) or Fourier transform infrared (FTIR) spectroscopy.

[0055] In the cyclic olefin copolymer example, the glass transition temperature of the shrinkage additive will be greater than the peak melting temperatures of the first and second ethylene-based polymers. Cyclic polyolefin copolymers can have glass transition temperatures ranging from 135°C to 200°C, as measured by differential scanning calorimetry. For example, cyclic polyolefin copolymers may have glass transition temperatures of 135°C or higher, or 140°C or higher, or 145°C or higher, 150°C or higher, or 155°C or higher, or 160°C or higher, or 165°C or higher, or 170°C or higher, or 175°C or higher, or 180°C or higher, or 185°C or higher, or 190°C or higher, or 195°C or higher, while simultaneously 200°C or lower, or 195°C or lower, or 190°C or lower, or 185°C or lower, or 180°C or lower, or 175°C or lower, or 170°C or lower, or 165°C or lower, or 160°C or lower, or 155°C or lower, or 150°C or lower, or 145°C or lower, or 140°C or lower, as measured by differential scanning calorimetry.

[0056] Cyclic polyolefin copolymers can have densities ranging from 0.95 g / cc to 1.10 g / cc, as measured according to ASTM D792. For example, cyclic polyolefin copolymers can have densities of 0.95 g / cc or greater, or 0.96 g / cc or greater, or 0.97 g / cc or greater, or 0.98 g / cc or greater, or 0.99 g / cc or greater, or 1.00 g / cc or greater, or 1.01 g / cc or greater, or 1.02 g / cc or greater, or 1.03 g / cc or greater, or 1.04 g / cc or greater, or 1.05 g / cc or greater, or 1.06 g / cc or greater, or 1.07 g / cc or greater, or 1.08 g / cc or greater, or 1.09 g / cc or greater. Meanwhile, the densities are 1.10 g / cc or less, or 1.09 g / cc or less, or 1.08 g / cc or less, or 1.07 g / cc or less, or 1.06 g / cc or less, or 1.05 g / cc or less, or 1.04 g / cc or less, or 1.03 g / cc or less, or 1.02 g / cc or less, or 1.01 g / cc or less, or 1.00 g / cc or less, or 0.99 g / cc or less, or 0.98 g / cc or less, or 0.97 g / cc or less, or 0.96 g / cc or less, as measured according to ASTM D792.

[0057] The polymer shrinkage additive may additionally or alternatively be based on a polypropylene polymer. In the polypropylene-based polymer, the peak melt temperature of the shrinkage additive will be higher than that of the first ethylene-based polymer and the second ethylene-based polymer. As used herein, a "propylene-based" polymer is a polymer in which more than 50% by weight of the monomer is propylene, but other comonomers may also be used. Propylene-based polymers include ethylene and one or more C3-C... 20α-olefin comonomers, such as ethylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, and 1-octene. Propylene-based polymers may contain 50% or more, 60% or more, 70% or more, 80% or more, 85% or more, 90% or more, or 91% or more, or 92% or more, or 93% or more, or 94% or more, or 95% or more, or 96% or more, or 97% or more, or 97.5% or more, or 98% or more, or 99% or more, while simultaneously containing 99.5% or less. 99% or less, or 98% or less, or 97% or less, or 96% or less, or 95% or less, or 94% or less, or 93% or less, or 92% or less, or 91% or less, or 90% or less, or 85% or less, or 80% or less, or 70% or less, or 60% or less propylene monomer, as measured using nuclear magnetic resonance (NMR) or Fourier transform infrared (FTIR) spectroscopy.

[0058] The propylene-based polymer may have any of the characteristics (i) to (iv): (i) the polypropylene-based polymer contains 90% by weight or more propylene based on the total weight of the polypropylene-based polymer; (ii) the polypropylene-based polymer has a melting peak temperature of 160°C to 200°C, as measured by differential scanning calorimetry; (iii) the polypropylene-based polymer has a density of 0.89 g / cc to 0.92 g / cc, as measured by ASTM D792; and (iv) any combination of two or more of the characteristics (i) to (iii).

[0059] Polypropylene-based polymers have a melting peak temperature of 135°C to 200°C, as measured by differential scanning calorimetry. For example, a polypropylene-based polymer has a melting peak temperature of 135°C or higher, or 140°C or higher, or 145°C or higher, or 150°C or higher, or 155°C or higher, or 160°C or higher, or 165°C or higher, or 170°C or higher, or 175°C or higher, or 180°C or higher, or 185°C or higher, or 190°C or higher, or 195°C or higher, while simultaneously 200°C or lower, or 195°C or lower, or 190°C or lower, or 185°C or lower, or 180°C or lower, or 175°C or lower, or 170°C or lower, or 165°C or lower, or 160°C or lower, or 155°C or lower, or 150°C or lower, or 145°C or lower, or 140°C or lower, as measured by differential scanning calorimetry.

[0060] Polypropylene-based polymers can have densities ranging from 0.89 g / cc to 0.92 g / cc, as measured according to ASTM D792. Cyclic polyolefins, for example, can have densities of 0.890 g / cc or greater, or 0.895 g / cc or greater, or 0.900 g / cc or greater, or 0.905 g / cc or greater, or 0.910 g / cc or greater, or 0.915 g / cc or greater, while simultaneously having densities of 0.920 g / cc or less, or 0.915 g / cc or less, or 0.910 g / cc or less, or 0.905 g / cc or less, or 0.900 g / cc or less, or 0.895 g / cc or less, as measured according to ASTM D792.

[0061] Compatibilizer

[0062] The polymer composition may contain a compatibilizer. The compatibilizer may be a random copolymer, block copolymer, or a combination thereof. The compatibilizer may contain ethylene and one or more monomers, such as α-olefins (e.g., C3–C). 20 α-olefin comonomers, such as propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, and 1-octene, as well as polar comonomers. Where applicable, the monomers of the compatibilizer may be isotactic, syndiotactic, atactic, or a combination thereof throughout the polymer chain. The compatibilizer may be from 5% by weight of ethylene to 95% by weight of ethylene based on the total weight of the compatibilizer, with the balance being one or more comonomers. For example, a compatibilizer may contain 5% or more by weight, or 10% or more by weight, or 20% or more by weight, or 30% or more by weight, or 40% or more by weight, or 50% or more by weight, or 60% or more by weight, or 70% or more by weight, or 80% or more by weight, or 85% or more by weight, or 90% or more by weight, while simultaneously containing 95% or less by weight, or 90% or less by weight, or 80% or less by weight, or 70% or less by weight, or 60% or less by weight, or 50% or less by weight, or 40% or less by weight, or 30% or less by weight, or 20% or less by weight, or 10% or less by weight, of ethylene monomer, as measured using nuclear magnetic resonance (NMR) or Fourier transform infrared (FTIR) spectroscopy, with the balance being one or more comonomers.

[0063] The polymer composition may contain 0% to 15% compatibilizer based on the total weight of the polymer composition. For example, the polymer composition may contain 0% or more, or 1% or more, or 2% or more, or 3% or more, or 4% or more, or 5% or more, or 6% or more, or 7% or more, or 8% or more, or 9% or more, or 10% or more, or 11% or more, or 12% or more, or 13% or more, or 14% or more, while simultaneously 15% or less, or 14% or less, or 13% or less, or 12% or less, or 11% or less, or 10% or less, or 9% or less, or 8% or less, or 7% or less, or 6% or less, or 5% or less, or 4% or less, or 3% or less, or 2% or less, or 1% or less compatibilizer based on the total weight of the polymer composition.

[0064] additive

[0065] The polymer composition may contain additional additives in the following forms: antioxidants, crosslinking aids, curing accelerators and scorch inhibitors, processing aids, coupling agents, ultraviolet stabilizers (including UV absorbers), antistatic agents, additional nucleating agents, slip agents (i.e., silicone rubber), lubricants, viscosity control agents, tackifiers, antiblocking agents, surfactants, bulking agents, deacidifiers, anti-dripping agents (e.g., ethylene vinyl acetate), and metal deactivators. The polymer composition may contain 0.01% to 20% by weight of one or more additional additives.

[0066] UV light stabilizers can contain hindered amine light stabilizers (“HALS”) and UV light absorbers (“UVA”) additives. Representative UVA additives include benzotriazole types, such as TINUVIN326, commercially available from BASF, Inc. ™ Light stabilizer and TINUVIN 328 ™ Light stabilizers. Blends of HAL and UVA additives are also effective.

[0067] Antioxidants can include hindered phenols, such as tetra[methylene(3,5-di-tert-butyl-4-hydroxycinnamate)]methane; bis[(β-(3,5-di-tert-butyl-4-hydroxybenzyl)methylcarboxyethyl)]-sulfides, 4,4'-thiobis(2-methyl-6-tert-butylphenol), 4,4'-thiobis(2-tert-butyl-5-methylphenol), 2,2'-thiobis(4-methyl-6-tert-butylphenol), and thiodiethylenebis(3,5-di-tert-butyl-4-hydroxy)-hydrogenated cinnamate; phosphites and phosphonites. Such as tris(2,4-di-tert-butylphenyl) phosphites and di-tert-butylphenyl phosphites; thiolated compounds such as dilauryl thiodipropionate, dimyristyl thiodipropionate and distearate thiodipropionate; various siloxanes; polymerized 2,2,4-trimethyl-1,2-dihydroquinoline, n,n'-bis(1,4-dimethylpentyl-p-phenylenediamine), alkylated diphenylamine, 4,4'-bis(α,α-dimethylbenzyl)diphenylamine, diphenyl-p-phenylenediamine, mixed diaryl-p-phenylenediamines and other hindered amine degradation inhibitors or stabilizers.

[0068] Processing aids may include metal salts of carboxylic acids, such as zinc stearate or calcium stearate; fatty acids, such as stearic acid, oleic acid, or erucic acid; fatty amides, such as stearamide, oleamide, erucic acid, or N,N'-ethylenebis-stearamide; polyethylene wax; oxidized polyethylene wax; polymers of ethylene oxide; copolymers of ethylene oxide and propylene oxide; vegetable waxes; petroleum waxes; nonionic surfactants; silicone fluids, polysiloxanes, fluoropolymers, and / or fluoroelastomers.

[0069] Mixing

[0070] Components of the polymer composition can be added to a batch or continuous mixer for melt blending. Components can be added in any order, or one or more masterbatches can be prepared first for blending with other components. Melt blending can be carried out at a temperature above the maximum blending temperature of the highest melt polymer but below 285°C. The melt-blended composition can then be fed into an extruder or injection molding machine, or molded through a die into the desired article, or converted into granules, tapes, strips, films, or some other form for storage or preparation of material to be supplied to the next forming or processing step. Optionally, if formed into granules or some similar configuration, the granules, etc., can be coated with an anti-sticking agent to facilitate handling during storage.

[0071] Examples of compounding equipment that can be used include internal batch mixers, continuous single or twin screw mixers, or kneading continuous extruders. The type of mixer used and the operating conditions of the mixer will affect the properties of the composition, such as viscosity, volume resistivity, and the surface smoothness of the extrusion.

[0072] cable

[0073] The polymer composition can be used in cables. In some examples, the cable may be a coated conductor. In other examples, the cable may be an optical fiber cable. In the example of a coated conductor, the coated conductor includes a conductor and a coating on the conductor, the coating comprising the polymer composition. The polymer composition is at least partially positioned around the conductor to create the coated conductor. The conductor may include a conductive metal or an optically transparent structure.

[0074] In the example of a fiber optic cable, the cable includes a conductor, and a polymer composition is positioned around the conductor. The polymer composition may be in the form of a buffer tube, one or more sheath layers on the cable, and / or as other components in the cable. The conductor may include optical fibers or other transmission components.

[0075] Example

[0076] Material

[0077] The following materials are used to form the embodiments (“IE”) and comparative examples (“CE”) of the present invention.

[0078] HDPE is a single-peaked high-density polyethylene with a hexene comonomer. Its density, as measured by ASTM D792, is 0.955 g / cc, its peak melt temperature, as measured by differential scanning calorimetry, is 130°C, and its melt index (I2) is 1.5 g / 10 min. HDPE is commercially available from Dow Chemical Company, Midland, Michigan.

[0079] LLDPE is a linear low-density polyethylene with butene comonomers, having a density of 0.92 g / cc as measured by ASTM D792, a peak melt temperature of 120°C as measured by differential scanning calorimetry, and a melt index (I2) of 0.65 g / 10 min. LLDPE is commercially available from Dow Chemical Company, Midland, Michigan.

[0080] SILG is an organosilicone compound consisting of 35% by weight of a blend of polydimethylsiloxane, which is dimethylvinylsiloxy-terminated and has a Mw of 696,000 g / mol as measured by gel permeation chromatography, with the remainder being EP2. PDMS of Si Gum is available from Dow Chemical Company, Midland, Michigan.

[0081] CBMB is a carbon black masterbatch consisting of carbon black dispersed in linear low-density polyethylene and is commercially available from Dow Chemical Company in Midland, Michigan.

[0082] MDPE is a medium-density polyethylene with a density of 0.935 g / cc as measured according to ASTM D792. MDPE is commercially available from Dow Chemical Company, Midland, Michigan.

[0083] PEG is polyethylene glycol with a molecular weight of 20,000 g / mol as measured by gel permeation chromatography, and is commercially available from Clariant, Muttenz, Switzerland.

[0084] AO is a mixture of 50% by weight CAS No. 6683-19-8 and 50% by weight CAS No. 31570-04-4, which is usually marketed under the trade name IRGANOX. ™ B225 is sold by BASF in Ludwigshafen, Germany.

[0085] HA10 is a polymeric UV stabilizer with CAS registration number 136504-96-6 and a weight-average molecular weight of approximately 10,000 as measured by component GPC. HA10 can be traded under the name UVASORB. ™ HA10 was purchased from 3V Sigma Corporation in Georgetown, South Carolina, USA.

[0086] HA88 is an oligomeric UV stabilizer with CAS registration number 136504-96-6 and a weight-average molecular weight of approximately 3,000 as measured by component GPC. HA88 can be traded under the name UVASORB. ™ HA88 was purchased from 3V Sigma Corporation in Georgetown, South Carolina, USA.

[0087] The elastomer is a polyethylene elastomer with a density of 0.868 g / cc as measured according to ASTM D792, and can be used as a VERSIFY elastomer. ™ 4301 was purchased from Dow Chemical Company in Midland, Michigan.

[0088] COCP is a cyclic olefin copolymer of ethylene and norbornene. COCP has a glass transition temperature of 180°C as measured by differential scanning calorimetry and a density of 1.02 g / cc as measured by ASTM D792. COCP can be used as a TOPAS... ™6017S04 was purchased from Topas GmbH, Raunheim, Hessen, Germany.

[0089] PROP is a propylene homopolymer with a peak melting temperature of 167°C, a density of 0.90 g / cc as measured according to ASTM D792, and is available from LyondellBasell, Houston, Texas.

[0090] COMP is a 50 wt% ethylene and 50 wt% isotactic propylene olefin block copolymer with a density of 0.904 g / cc as measured according to ASTM D792, and is commercially available from Dow Chemical Company, Midland, Michigan.

[0091] Sample preparation

[0092] For each embodiment, each sample was prepared by combing all the materials listed in Table 1 into the mixing bowl of a Brabender mixer with a Banbury blade. The mixer was turned on and the materials were mixed at a temperature of 190°C to 220°C at 40 to 50 rpm. The compound was granulated and extruded using Brabender microwires onto a copper conductor with a diameter of 1.651 mm and a wall thickness of 0.762 mm.

[0093] Test methods

[0094] Differential Scanning Calorimetry (“DSC”): Differential scanning calorimetry (“DSC”) was performed on a TA Instruments Q2000 DSC using a 5 mg sample that had been pressed into a film. DSC was performed according to the following steps: equilibration at 30.00 °C; ramping up to 140.00 °C at 10.00 °C / min; holding the temperature constant for 1.00 min; ramping down to 0.00 °C at 10.00 °C / min; holding the temperature constant for 3.00 min; and ramping up to 180.00 °C at 10.00 °C / min. The melting peak temperature was reported as the temperature at which the peak enthalpy was reached.

[0095] PES Testing: The extruded wire was first conditioned at room temperature for one day. A 122 cm long test sample was prepared by stretching the copper conductor and removing the polymer sheath in single pieces. Twenty-four hours after removing the cable sheath from the conductor, the post-extrusion shrinkage was measured on the cable sheath. The sample length was measured using calipers with a resolution of + / - 0.0005 inches. Shrinkage was measured as the total shrinkage rate of the sample length. The reported value is the average of five individual samples.

[0096] CS Test: Following the post-extrusion shrinkage test, cyclic shrinkage is measured on the same cable sheath as in the post-extrusion test. The CS test is performed by placing the sheath in a 40°C oven and allowing it to equilibrate for 20 minutes. The temperature is then increased to 100°C at a rate of 0.5°C / min. Once 100°C is reached, the sheath is allowed to equilibrate for 1 hour. The temperature is then decreased back to 40°C at a rate of 0.5°C / min. This process of equilibration at 40°C, increasing the temperature, equilibrating at 100°C, and then cooling is repeated four more times. The reported shrinkage data is the average of five individual measurements, each performed on a different sheath.

[0097] result

[0098] Table 1 provides the composition (wt%) and shrinkage properties of CE1-CE3 and IE1-IE8. In Table 1, the term "NM" indicates that the value was not measured.

[0099] Table 1

[0100]

[0101] Referring now to Table 1, CE1 indicates that conventional polymer compositions for cables do not meet the target characteristics of 0.5% or less post-extrusion shrinkage and 2.20% or less cyclic shrinkage. CE2 indicates that even the addition of an elastomer to conventional compositions does not enable the polymer composition to achieve the target characteristics. CE3 indicates that HDPE itself cannot achieve the target shrinkage characteristics. IE1-IE4 surprisingly show that, although the use of cyclic copolymers to prepare shrink films is known, the addition of cyclic copolymers as shrinkage additives reduces post-extrusion shrinkage and cyclic shrinkage. Similarly, IE5-IE8 also surprisingly show that the addition of polypropylene-based polymers enables the polymer composition to achieve the target shrinkage characteristics.

Claims

1. A polymer composition comprising: Based on the total weight of the polymer composition, the first ethylene-based polymer comprises 20% to 70% by weight, wherein the first ethylene-based polymer has a density of 0.93 g / cc to 0.970 g / cc, as measured according to ASTM D792. Based on the total weight of the polymer composition, a second ethylene-based polymer comprises 5% to 35% by weight, wherein the second ethylene-based polymer has a density of 0.885 g / cc to 0.93 g / cc, as measured according to ASTM D792; and Based on the total weight of the polymer composition, there is 1% to 55% by weight of a polymer shrinkage additive, wherein the peak melting temperature or glass transition temperature of the polymer shrinkage additive is greater than the peak melting temperature of the first ethylene-based polymer and the second ethylene-based polymer.

2. The polymer composition according to claim 1, wherein the polymer composition has any one of characteristics (i) to (vi): (i) The first ethylene-based polymer is bimodal; (ii) The first ethylene-based polymer has a density of 0.950 g / cc to 0.970 g / cc, as measured according to ASTM D792; (iii) The first ethylene-based polymer has a melting peak temperature of 125°C to 200°C, as measured by differential scanning calorimetry; (iv) The first ethylene-based polymer is a copolymer of ethylene and hexene; (v) The first ethylene-based polymer has a melt index of 1.0 g / 10 min to 2.5 g / 10 min, as measured according to ASTM D1238; and (vi) Any combination of two or more of the features (i) to (v).

3. The polymer composition according to any one of claims 1 and 2, wherein the polymer composition has any one of characteristics (i) to (vi): (i) The second ethylene-based polymer is linear or substantially linear; (ii) The second ethylene-based polymer has a density of 0.91 g / cc to 0.93 g / cc, as measured according to ASTM D792; (iii) The second ethylene-based polymer has a melting peak temperature of 110°C to 130°C, as measured by differential scanning calorimetry; (iv) The second ethylene-based polymer is a copolymer of ethylene and butene; (v) The second ethylene-based polymer has a melt index of 0.3 g / 10 min to 1.0 g / 10 min, as measured according to ASTM D1238; and (vi) Any combination of two or more of the features (i) to (v).

4. The polymer composition according to any one of claims 1 to 3, wherein the polymer shrinkage additive is selected from any one of (i) to (iii): (i) Cyclic olefin copolymers; (ii) Polypropylene-based polymers; and Combinations of (iii), (i), and (ii).

5. The polymer composition according to claim 4, wherein the polymer shrinkage additive is the cyclic polyolefin copolymer and has any one of characteristics (i) to (v): (i) The cyclic polyolefin copolymer is a copolymer of ethylene and norbornene; (ii) The cyclic polyolefin copolymer is a copolymer of ethylene and 50% to 90% by weight of cyclic comonomers based on the total weight of the cyclic polyolefin copolymer; (iii) The cyclic polyolefin copolymer has a glass transition temperature of 135°C to 200°C, as measured by differential scanning calorimetry; (iv) The cyclic polyolefin copolymer has a density of 0.95 g / cc to 1.10 g / cc, as measured according to ASTM D792; and (v) Any combination of two or more of the features (i) to (iv).

6. The polymer composition according to claim 4, wherein the polymer shrinkage additive is the polypropylene-based polymer and has any one of characteristics (i) to (iii): (i) The polypropylene-based polymer is 90% by weight or more of propylene based on the total weight of the polypropylene-based polymer; (ii) The polypropylene-based polymer has a melting peak temperature of 135°C to 200°C, as measured by differential scanning calorimetry. (iii) The polypropylene-based polymer has a density of 0.89 g / cc to 0.92 g / cc, as measured according to ASTM D792; and (iv) Any combination of two or more of the features (i) to (iii).

7. The polymer composition according to claim 6, wherein the polymer composition further comprises: Compatibilizer, ranging from 0.5% to 15% by weight based on the total weight of the polymer composition.

8. The polymer composition according to any one of claims 1 to 7, wherein the polymer composition comprises 20% to 50% by weight of the polymer shrinkage additive based on the total weight of the polymer composition.

9. The polymer composition according to any one of claims 1 to 9, wherein the polymer composition has any one of characteristics (i) to (vi): (i) Post-extrusion shrinkage of 0.50 or less, as measured by PES testing; (ii) 2.2 or less of cyclic contraction, as measured according to the CS test; (iii) Density of 0.94 g / cc to 0.98 g / cc, as measured according to ASTM D792; (iv) Melt index from 0.5 g / 10 min to 2.0 g / 10 min; (v) ESCR of 2000 hours or longer, as measured in 10% Igepal according to ASTM D1693-15; and Any combination of any two of (vi)(i) to (iv).

10. A cable, the cable comprising: conductor; and The polymer composition according to any one of claims 1 to 9 is positioned around the conductor.

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