Polyethylene composition and articles made therefrom

Abstract

The invention provides an ethylene-based composition comprising a blend of: an ultra-high molecular weight polyethylene having an intrinsic viscosity of 5 to 50 deciliters / gram; a thermoplastic polyolefin elastomer having a density of 0.850 to 0.910 g / cc; and, optionally, a fluoropolymer.

Description

Technical Field

[0001] The embodiments of this disclosure generally relate to polyethylene compositions and the application of polyethylene compositions in the manufacture of molded articles, such as geomembranes, pipes or tubes, pipe coatings, pipe linings, pipe fittings, and environmental pool linings. Background Technology

[0002] Geomembranes, pipes, tubes, pipe coatings, pipe liners, or environmental pool liners made of polyolefins (e.g., polyethylene resin) are relatively lightweight, easy to handle, and non-corrosive. Existing polyolefin materials offer relatively high rigidity and flexibility, making them suitable for use in or on the ground when forming geomembranes, pipes, tubes, pipe coatings, pipe liners, or environmental pool liners. However, existing geomembranes, pipes, tubes, pipe coatings, pipe liners, or environmental pool liners can withstand significant abrasion during installation and contact with slurries or other abrasive materials during use. In some applications, existing geomembranes, pipes, tubes, pipe coatings, pipe liners, or environmental pool liners may not be sufficient to handle routine contact with slurries or abrasive materials. For example, geomembranes or environmental pool liners may be used to prevent contaminants from entering the ground or groundwater; however, these products may typically come into contact with concrete or other abrasive surfaces during use. To provide another example where existing technologies may be insufficient to handle contact with slurry or abrasive materials, HDPE pipes, pipe linings, pipe coatings, or pipe fittings may not be able to transport gravel-based slurries, such as mining slurries, petroleum-based slurries, and / or solvent-based slurries. Therefore, these diverse applications may require products with high abrasion resistance.

[0003] Therefore, there is a need for alternative polyethylene compositions with good grinding properties and good processability. Summary of the Invention

[0004] The embodiments herein disclose ethylene compositions comprising blends of ultra-high molecular weight polyethylene with an intrinsic viscosity of 5 to 50 dL / g, thermoplastic polyolefin elastomers with a density of 0.850 to 0.910 g / cc, and optionally, fluoropolymers. Molded articles, such as geomembranes, comprising at least one component formed from the ethylene compositions described herein are also disclosed herein.

[0005] Additional features and advantages of the embodiments will be set forth in the detailed description below, and will be recognized in part by those skilled in the art from the description or by practice of the embodiments described herein (including the detailed description below, the claims and the drawings).

[0006] It should be understood that the above and the following descriptions describe various embodiments and are intended to provide an overview or framework for understanding the nature and characteristics of the claimed subject matter. Detailed Implementation

[0007] Reference will now be made in detail to examples of ethylene-based compositions comprising blends of ultra-high molecular weight polyethylene, thermoplastic polyolefin elastomers, and optionally fluoropolymers. As used herein, an ethylene-based composition refers to a composition in which, by weight of the total polymers present in the composition, the polyethylene resin present in the composition comprises at least 60%, at least 70%, or at least 80%. “Polyethylene” includes ethylene homopolymers and copolymers of ethylene and one or more comonomers, wherein ethylene is the major component of the copolymer. The compositions described herein are suitable for use in geomembrane, pipe or tube, pipe coating, pipe lining, pipe fitting, and environmental pool lining applications. However, it should be noted that these are merely illustrative embodiments of the examples disclosed herein. The examples are applicable to other techniques susceptible to problems similar to those discussed above. For example, the compositions described herein can be used in drip irrigation tapes and tubes, membranes, sheets, tapes, fibers, caps and closures, and articles molded by molding methods, including blow molding, compression molding, and injection molding (e.g., injection molding of pipe fittings), all of which are within the scope of this embodiment of the invention.

[0008] The compositions described herein may comprise 30 wt% to 70 wt% of ultra-high molecular weight polyethylene. All individual values ​​and subranges of 30 wt% to 70 wt% are included and disclosed herein. For example, the compositions may comprise the lower limit of 30 wt%, 35 wt%, 40 wt%, 45 wt%, or 50 wt% to the upper limit of 70 wt%, 65 wt%, 60 wt%, 55 wt%, or 50 wt% of ultra-high molecular weight polyethylene. In some embodiments, the compositions comprise 35 wt% to 70 wt%, 35 wt% to 65 wt%, or 40 wt% to 65 wt% of ultra-high molecular weight polyethylene. In addition to the amount of ultra-high molecular weight polyethylene, the compositions may further comprise 30 wt% to 70 wt% of thermoplastic polyolefin elastomer. All individual values ​​and subranges of 30 wt% to 70 wt% are included and disclosed herein. For example, the composition may comprise 30 wt%, 35 wt%, 40 wt%, 45 wt%, or 50 wt% to 70 wt%, 65 wt%, 60 wt%, 55 wt%, or 50 wt% of thermoplastic polyolefin elastomer. In some embodiments, the composition comprises 30 wt% to 65 wt%, 30 wt% to 60 wt%, or 35 wt% to 60 wt% of thermoplastic polyolefin elastomer.

[0009] Ultra-high molecular weight polyethylene

[0010] The ultra-high molecular weight polyethylene described in this article can be either a polyethylene homopolymer or an ethylene / α-olefin copolymer, each possessing an ultra-high molecular weight. This can be determined by the melt index (I2), high-load melt index (I... 21 Viscosity measurements (e.g., intrinsic or melt viscosity) and / or GPC are used to indicate this. Suitable copolymers may include α-olefins having 3 to 10 carbon atoms, or in some embodiments, α-olefins having 3 to 5 carbon atoms. In some embodiments, the ethylene / α-olefin copolymer may contain up to about 5 mol% α-olefin comonomer, up to about 2 mol% α-olefin comonomer, or up to about 1 mol% α-olefin comonomer. Suitable ultra-high molecular weight polyethylene may include, but is not limited to, products available from Ticona Engineering Polymers. 4050 polymer and available from Braskem Polymer 6540 or 6541.

[0011] In the embodiments described herein, the intrinsic viscosity of ultra-high molecular weight polyethylene (UHMWPE) is 5 to 50 dL / g. All individual values ​​and sub-ranges of 5 to 50 dL / g are disclosed and included herein. For example, the intrinsic viscosity of UHMWPE may range from a lower limit of 5, 7, 10, 12, 15, or 20 dL / g to an upper limit of 50, 45, 40, 35, 30, or 25 dL / g. In some embodiments, the intrinsic viscosity of UHMWPE is 5 to 50 dL / g, 5 to 40 dL / g, 7 to 40 dL / g, or 10 to 30 dL / g. The intrinsic viscosity may be determined according to ASTM D 4020.

[0012] In the embodiments described herein, the average particle size D50 of ultra-high molecular weight polyethylene (UHMWPE) is 100-220 micrometers. All values ​​and subranges are included herein. For example, in some embodiments, the average particle size D50 of UHMWPE is 180-220 micrometers. In other embodiments, the average particle size D50 of UHMWPE is 120-140 micrometers. The average particle size D50 can be determined according to ASTM D1921.

[0013] In the embodiments described herein, the melt temperature of ultra-high molecular weight polyethylene (UHMWPE) is 125°C to 140°C. All values ​​and sub-ranges are included herein. For example, in some embodiments, the melt temperature of UHMWPE is 125°C to 140°C. In other embodiments, the melt temperature of UHMWPE is 128°C to 138°C. In still other embodiments, the melt temperature of UHMWPE is 130°C to 135°C. The melt temperature can be determined using differential scanning calorimetry (DSC) according to ASTM D3418.

[0014] In the embodiments described herein, the weight-average molecular weight of ultra-high molecular weight polyethylene (UHMWPE) may be greater than or equal to 1,000,000 g / mol. In some embodiments, the weight-average molecular weight of UHMWPE may be greater than or equal to 2,000,000 g / mol or greater than or equal to 3,000,000 g / mol. In other embodiments, the weight-average molecular weight of UHMWPE may be greater than or equal to 1,000,000 g / mol and less than or equal to 10,000,000 g / mol, greater than or equal to 2,000,000 g / mol and less than or equal to 10,000,000 g / mol, greater than or equal to 3,000,000 g / mol and less than or equal to 9,000,000 g / mol, or greater than or equal to 3,000,000 g / mol and less than or equal to 8,000,000 g / mol. The weight-average molecular weight can be determined by GPC or light scattering.

[0015] In the embodiments described herein, the density of ultra-high molecular weight polyethylene (UHMWPE) may be from 0.915 to 0.950 g / cc. All values ​​and subranges are included herein. For example, in some embodiments, the density of UHMWPE may be from 0.920 to 0.945 g / cc, 0.920 to 0.940 g / cc, 0.920 to 0.935 g / cc, 0.920 to 0.930 g / cc, or 0.921 to 0.928 g / cc. The density may be determined according to ASTM D792.

[0016] thermoplastic polyolefin elastomer

[0017] Thermoplastic polyolefin elastomers (TPEs) are (1) polyolefins that have the properties of an elastomer, i.e., can be stretched beyond their original length and retract to substantially their original length when released, and (2) can be processed like thermoplastics, i.e., soften when exposed to heat and return to substantially their original conditions when cooled to room temperature. In the examples herein, the density of the TPE is from 0.850 to 0.910 g / cc. All individual values ​​and subranges are included and disclosed herein. For example, the density of TPE can range from a lower limit of 0.850, 0.852, 0.855, 0.860, 0.862, 0.865, 0.870, 0.875, or 0.880 g / cc to an upper limit of 0.910, 0.908, 0.905, 0.902, 0.900, 0.898, 0.895, 0.890, 0.885, or 0.880 g / cc. In some embodiments, the density of TPE is from 0.852 to 0.910 g / cc, from 0.855 to 0.900 g / cc, or from 0.855 to 0.895 g / cc.

[0018] In exemplary embodiments of the compositions disclosed herein, the TPE component comprises an ethylene / α-olefin interpolymer and / or an ethylene / α-olefin multiblock interpolymer. Suitable ethylene / α-olefin interpolymers may include ENGAGE, available from The Dow Chemical Company (Midland, MI). TM and AFFINITY TM Elastomers and plasmons, and suitable ethylene / α-olefin multiblock interpolymers (OBCs) may include INFUSE, available from Dow Chemical Company (Midland, Michigan). TM Resin.

[0019] Ethylene / α-olefin interpolymer

[0020] Ethylene / α-olefin interpolymers are ethylene and at least one C3-C 20 Copolymers of α-olefins. Examples of suitable comonomers include C3-C4. 20 α-Olefins, such as propylene, isobutene, 1-butene, 1-hexene, 1-pentene, 4-methyl-1-pentene, 1-heptene, 1-octene, 1-nonene, 1-decene, etc. In some embodiments, the comonomer is 1-butene or 1-octene. The ethylene / α-olefin interpolymer has more than 50% ethylene based on the total amount of polymerizable monomers.

[0021] Ethylene / α-olefin interpolymers can be homogeneously branched linear or homogeneously branched substantially linear ethylene / α-olefin interpolymers. Methods for preparing homogeneous polymers are disclosed in U.S. Patent 5,206,075; U.S. Patent 5,241,031; and PCT International Application WO 93 / 03093; each of these patents is incorporated herein by reference in its entirety. Further details regarding the production of homogeneous ethylene / α-olefin copolymers are disclosed in U.S. Patent 5,206,075; U.S. Patent 5,241,031; PCT International Publication No. WO 93 / 03093; and PCT International Publication No. WO 90 / 03414; all four patents are incorporated herein by reference in their entirety.

[0022] The terms "homogeneous" and "homogeneously branched" are used to refer to ethylene / α-olefin polymers (or interpolymers) in which one or more comonomers are randomly distributed within a given polymer molecule, and substantially all polymer molecules have the same ethylene to one or more comonomer ratio. Homogeneously branched ethylene interpolymers include linear ethylene interpolymers and substantially linear ethylene interpolymers.

[0023] Included in uniformly branched linear ethylene interpolymers are ethylene interpolymers that have no long-chain branches, but do have short-chain branches derived from the comonomers that polymerize into the interpolymer, and which are uniformly distributed within the same polymer chain and between different polymer chains. That is, uniformly branched linear ethylene interpolymers have no long-chain branches, as is the case for linear low-density polyethylene polymers or linear high-density polyethylene polymers produced using uniform branching polymerization processes (such as those described, for example, by Elston in U.S. Patent 3,645,992).

[0024] The substantially linear ethylene interpolymers used in this invention are described in U.S. Patent Nos. 5,272,236 and 5,278,272; the entire contents of each are herein. As discussed above, a substantially linear ethylene interpolymer is one in which the comonomers are randomly distributed within a given interpolymer molecule and wherein substantially all interpolymer molecules have the same ethylene / comonomer ratio within the interpolymer. The substantially linear ethylene interpolymers are prepared using a defined geometry catalyst. Examples of defined geometry catalysts and such formulations are described in U.S. Patent Nos. 5,272,236 and 5,278,272.

[0025] Furthermore, substantially linear ethylene interpolymers are uniformly branched ethylene polymers with long-chain branches. The long-chain branches have a comonomer distribution approximately the same as the polymer backbone and may have a length approximately the same as the polymer backbone. As discussed above, "substantially linear" generally refers to polymers with an average substitution of 0.01 long-chain branches per 1000 total carbon atoms (including both main chain and branched carbon atoms) to 3 long-chain branches per 1000 total carbon atoms. Commercial examples of substantially linear polymers include ENGAGE. TM Polymers (Dow Chemical Company) and AFFINITY TM Polymer (Dow Chemical Company).

[0026] In some embodiments, the molecular weight distribution (Mw / Mn or weight-average molecular weight / number-average molecular weight) of the ethylene / α-olefin interpolymer is 1 to 5, 1.5 to 4, or 2 to 3. All individual values ​​and subranges of 1 to 5 are included and disclosed herein. Weight-average molecular weight and number-average molecular weight can be determined using gel permeation chromatography.

[0027] In some embodiments, the density of the ethylene / α-olefin interpolymer is greater than or equal to 0.850 g / cc, greater than or equal to 0.855 g / cc, or greater than or equal to 0.860 g / cc, according to ASTM D792 or ISO 1183-187.

[0028] In some embodiments, the density of the ethylene / α-olefin interpolymer is less than or equal to 0.910 g / cc, less than or equal to 0.900 g / cc, or less than or equal to 0.880 g / cc, according to ASTM D792 or ISO 1183-187.

[0029] In some embodiments, the density of the ethylene / α-olefin interpolymer is 0.850 to 0.910 g / cc, 0.850 to 0.880 g / cc, or 0.860 to 0.880 g / cc, according to ASTM D792 or ISO 1183-187. All individual values ​​and subranges of 0.850 to 0.910 g / cc are included herein and disclosed herein.

[0030] In some embodiments, the melt index I2 (190°C / 2.16 kg) of the ethylene / α-olefin interpolymer is greater than or equal to 0.05 g / 10 min, greater than or equal to 0.1 g / 10 min, or greater than or equal to 0.2 g / 10 min, according to ASTM D1238 or ISO 1133.

[0031] In some embodiments, according to ASTM D1238 or ISO 1133, the melt index I2 (190°C / 2.16 kg) of the ethylene / α-olefin interpolymer is less than or equal to 50 g / 10 min, less than or equal to 25 g / 10 min, less than or equal to 10 g / 10 min, less than or equal to 5 g / 10 min, and / or less than or equal to 2 g / 10 min.

[0032] In some embodiments, the melt index I2 (190°C / 2.16 kg) of the ethylene / α-olefin interpolymer is 0.05 to 50 g / 10 min, 0.1 to 25 g / 10 min, and / or 0.2 to 10 g / 10 min, according to ASTM D1238 or ISO 1133. All individual values ​​and subranges of 0.05 to 50 g / 10 min are included herein and disclosed herein.

[0033] In some embodiments, the number-average molecular weight (Mn) of the ethylene / α-olefin interpolymer is from 40,000 g / mol to 200,000 g / mol, 50,000 g / mol to 150,000 g / mol, or 60,000 g / mol to 100,000 g / mol. All individual values ​​and subranges from 40,000 g / mol to 200,000 g / mol are included herein and disclosed herein.

[0034] In some embodiments, the weight-average molecular weight (Mw) of the ethylene / α-olefin interpolymer is from 80,000 g / mol to 400,000 g / mol, from 100,000 g / mol to 300,000 g / mol, or from 120,000 g / mol to 200,000 g / mol. All individual values ​​and subranges of 80,000 g / mol to 400,000 g / mol are included herein and disclosed herein.

[0035] In some embodiments, the Tg of the ethylene / α-olefin interpolymer is less than -30°C, less than -40°C, or less than -50°C.

[0036] The ethylene / α-olefin interpolymers disclosed herein can be produced by any method or means known to those skilled in the art.

[0037] In some embodiments, the TPE component may comprise more than one ethylene / α-olefin block copolymer or ethylene / α-olefin multiblock copolymer as described herein.

[0038] In some embodiments, the thermoplastic polyolefin elastomer component includes an ethylene / α-olefin multiblock interpolymer as described below.

[0039] Ethylene / α-olefin multiblock interpolymer

[0040] In some embodiments, at least one thermoplastic polyolefin elastomer is an ethylene / α-olefin multiblock copolymer. The term "olefin block copolymer" or "OBC" means (and is interchangeable with) "ethylene / α-olefin multiblock copolymer" and includes ethylene in polymeric form and one or more copolymerizable α-olefin comonomers, characterized in that the multiple blocks or segments of the two or more polymeric monomer units have different chemical and physical properties. The term "ethylene / α-olefin multiblock copolymer" includes block copolymers having two blocks (diblock) and more than two blocks (multiblock). The terms "polymer" and "copolymer" are used interchangeably herein. When the amount of "ethylene" or "comonomer" is mentioned in "polymer," it should be understood that this refers to its polymeric unit. In some embodiments, the ethylene / α-olefin copolymer is an ethylene / α-olefin multiblock copolymer. In some embodiments, the ethylene / α-olefin multiblock copolymer may be represented by the following formula:

[0041] (AB) n ,

[0042] Where n is at least 1, preferably an integer greater than 1, such as 2, 3, 4, 5, 10, 15, 20, 30, 40, 50, 60, 70, 80, 90, 100 or higher, "A" represents a hard block or segment and "B" represents a soft block or segment. Preferably, A and B are linked or covalently bonded in a substantially linear or linear manner relative to a substantially branched or substantially star-shaped configuration. In other embodiments, the A and B blocks are randomly distributed along the polymer chain. In other words, the block copolymer typically does not have the following structure:

[0043] AAA-AA-BBB-BB.

[0044] Ethylene comprises the majority molar fraction of the entire block copolymer, i.e., ethylene comprises at least 50 mol% of the entire polymer. More preferably, ethylene comprises at least 60 mol%, at least 70 mol%, or at least 80 mol%, wherein the substantially remaining portion of the entire polymer comprises at least one other comonomer, preferably an α-olefin having 3 or more carbon atoms, or 4 or more carbon atoms. In some embodiments, the ethylene / α-olefin multiblock copolymer may comprise 50 mol% to 90 mol% ethylene, or 60 mol% to 85 mol% ethylene, or 65 mol% to 80 mol% ethylene. For various ethylene / octene multiblock copolymers, the composition comprises an ethylene content greater than 80 mol% of the entire polymer and an octene content of 10 mol% to 15 mol%, or 15 mol% to 20 mol% of the entire polymer.

[0045] Ethylene / α-olefin multiblock copolymers comprise various amounts of "hard" segments and "soft" segments. A "hard" segment is a block in which, by weight of the polymer, the presence of ethylene is greater than 90 wt%, or 95 wt%, or greater than 95 wt%, or greater than 98 wt%, and up to 100 wt% of the polymeric units. In other words, by weight of the polymer, the comonomer content (the content of monomers other than ethylene) in the hard segment is less than 10 wt%, or 5 wt%, or less than 5 wt%, or less than 2 wt%, and can be as low as zero. In some embodiments, the hard segment comprises all or substantially all units derived from ethylene. A "soft" segment is a block in which, by weight of the polymer, the comonomer content (the content of monomers other than ethylene) is greater than 5 wt%, or greater than 8 wt%, greater than 10 wt%, or greater than 15 wt% of the polymeric units. In some embodiments, the comonomer content in the soft segment may be greater than 20% by weight, greater than 25% by weight, greater than 30% by weight, greater than 35% by weight, greater than 40% by weight, greater than 45% by weight, greater than 50% by weight, or greater than 60% by weight, and may be up to 100% by weight.

[0046] Soft segments may be present in ethylene / α-olefin polyblock copolymers at 1% to 99% by weight of the total weight, or at 5% to 95%, 10% to 90%, 15% to 85%, 20% to 80%, 25% to 75%, 30% to 70%, 35% to 65%, 40% to 60%, or 45% to 55% by weight of the total weight. Conversely, hard segments may be present in similar ranges. The weight percentages of soft and hard segments can be calculated based on data obtained from DSC or NMR. Such methods and calculations are disclosed in, for example, U.S. Patent No. 7,608,668, entitled "Ethylene / α-Olefin Block Interpolymers," filed March 15, 2006, in the name of Colin LPShan, Lonnie Hazlitt, et al., and assigned to Dow Global Technologies Inc., the disclosure of which is incorporated herein by reference in its entirety. Specifically, the weight percentages of hard and soft segments and the content of comonomers can be determined as described in columns 57 through 63 of US 7,608,668.

[0047] Ethylene / α-olefin multiblock copolymers are polymers comprising two or more chemically distinct regions or segments (referred to as “blocks”) preferably joined (or covalently bonded) in a linear manner; that is, polymers comprising chemically differentiated units joined end-to-end with respect to the functional group of the polymeric olefin rather than joined in a side-joining or grafting manner. In one embodiment, the blocks differ in the amount or type of comonomers incorporated, density, crystallinity, crystallite size of the polymer attributable to such compositions, type or degree of stereoisomerism (isosteryl or syndiotactic), regioregularity or regioirorality, amount of branching (including long-chain branching or hyperbranching), homogeneity, or any other chemical or physical property. Compared to existing block copolymers, including those produced by continuous monomer addition, stereochemical catalysts, or anionic polymerization, the ethylene / α-olefin multiblock copolymers of the present invention are characterized by a unique distribution of polymer polydispersity (PDI or Mw / Mn or MWD), polydisperse block length distribution, and / or polydisperse block number distribution, which in one embodiment is due to the effect of one or more shuttle agents used in their preparation combined with a variety of catalysts.

[0048] In one embodiment, the ethylene / α-olefin multiblock copolymer is produced in a continuous process and has a polydispersity index (Mw / Mn) of 1.7 to 3.5, or 1.8 to 3, or 1.8 to 2.5, or 1.8 to 2.2. When produced in a batch or semi-batch process, the ethylene / α-olefin multiblock copolymer has a Mw / Mn of 1.0 to 3.5, or 1.3 to 3, or 1.4 to 2.5, or 1.4 to 2.

[0049] In another embodiment, the ethylene / α-olefin multiblock copolymer is defined as having:

[0050] (A) Mw / Mn of about 1.7 to about 3.5, at least one melting point Tm in degrees Celsius and density d in grams per cubic centimeter, wherein the values ​​of Tm and d correspond to the following relationship:

[0051] Tm>-2002.9+4538.5(d)-2422.2(d) 2 , and / or

[0052] (B) Mw / Mn of about 1.7 to about 3.5, and characterized by a heat of fusion ΔH in J / g and a Δt in degrees Celsius, defined as the temperature difference between the highest DSC peak and the highest crystallization fraction (“CRYSTAF”) peak, wherein the values ​​of ΔT and ΔH have the following relationship:

[0053] For a ΔH greater than zero and at most 130 J / g, ΔT > -0.1299(H) + 62.81

[0054] For ΔH greater than 130 J / g, ΔT ≥ 48℃

[0055] The CRYSTAF peak is determined using at least 5% of the cumulative polymer, and if less than 5% of the polymer has an identifiable CRYSTAF peak, then the CRYSTAF temperature is 30°C; and / or

[0056] (C) Elastic recovery Re, measured as a percentage, of an ethylene / α-olefin interpolymer film compressed under 300% strain and one cycle, and having a density d in grams per cubic centimeter, wherein the values ​​of Re and d satisfy the following relationship when the ethylene / α-olefin interpolymer is substantially free of crosslinking phase:

[0057] Re>1481-1629(d); and / or

[0058] (D) A molecular weight fraction eluted between 40°C and 130°C when fractionated using TREF, characterized in that the fraction has a molar comonomer content of at least 5% higher than that of a comparable random ethylene interpolymer fraction eluted between the same temperatures, wherein the comparable random ethylene interpolymer has the same (one or more) comonomers and the melt index, density, and molar comonomer content (based on the whole polymer) are within 10% of that of the ethylene / α-olefin interpolymer; and / or

[0059] (E) has a storage modulus G'(25°C) at 25°C and a storage modulus G'(100°C) at 100°C, wherein the ratio of G'(25°C) to G'(100°C) is in the range of about 1:1 to about 9:1.

[0060] Ethylene / α-olefin multiblock copolymers may also have:

[0061] (F) Molecular fractions eluted between 40°C and 130°C when using TREF fractionation, characterized in that the fractions have a block index of at least 0.5 and at most about 1 and a molecular weight distribution Mw / Mn greater than about 1.3; and / or

[0062] (G) A mean block index greater than zero and at most about 1.0 and a molecular weight distribution Mw / Mn greater than about 1.3.

[0063] It should be understood that ethylene / α-olefin multiblock copolymers may have one, some, all, or any combination of properties (A)-(G). The block index can be determined as described in detail in U.S. Patent No. 7,608,668, which is incorporated herein by reference for the purposes described herein. Analytical methods for determining properties (A) to (G) are disclosed, for example, in column 31, lines 26 through 35, lines 44 of U.S. Patent No. 7,608,668, which is incorporated herein by reference for the purposes described herein.

[0064] Olefin block copolymers can be produced via chain shuttle methods, as described, for example, in U.S. Patent No. 7,858,706, which is incorporated herein by reference. Specifically, suitable chain shuttle agents and related information are listed in column 16, line 39 through column 19, line 44. Suitable catalysts are described in column 19, line 45 through column 46, line 19, and suitable co-catalysts are described in column 46, line 20 through column 51, line 28. The method is described throughout the document, but particularly in column 51, line 29 through column 54, line 56. The method is also described, for example, in: U.S. Patent Nos. 7,608,668; 7,893,166; and 7,947,793. Another exemplary catalytic method includes those disclosed in U.S. Patent No. 8,785,554, which is incorporated herein by reference.

[0065] In some embodiments, the density of the ethylene / α-olefin multiblock interpolymer is greater than 0.850 g / cc, further greater than 0.860 g / cc, and further greater than 0.865 g / cc. The density may be, for example, from 0.850 g / cc to 0.910 g / cc, from 0.860 g / cc to 0.905 g / cc, and from 0.860 to 0.900 g / cc. The density is measured using procedures according to ASTM D-792 or ISO 1183.

[0066] In some embodiments, the ethylene / α-olefin multiblock interpolymer and other copolymers have melting points greater than 90°C and further greater than 100°C. Melting points are measured by differential scanning calorimetry (DSC) as described in U.S. Publication 2006 / 0199930 (WO 2005 / 090427), which is incorporated herein by reference.

[0067] In some embodiments, the melt index (I2) of the ethylene / α-olefin multiblock interpolymer and other copolymers is greater than or equal to 0.1 g / 10 min, and further greater than or equal to 0.5 g / 10 min, and less than or equal to 50 g / 10 min, further less than or equal to 20 g / 10 min, and further less than or equal to 10 g / 10 min, as determined using ASTM D-1238 or ISO 1133 (190°C, 2.16 kg load).

[0068] Composition

[0069] In the embodiments described herein, the high-load melt index (I21) of the composition is from 0.1 to 40 g / 10 min. All individual values ​​and sub-ranges of 0.1 to 40 g / 10 min are included and disclosed herein. For example, in some embodiments, the high-load melt index (I21) of the composition is from 0.1 to 20 g / 10 min. In other embodiments, the high-load melt index (I21) of the composition is from 0.3 to 18 g / 10 min. In still other embodiments, the high-load melt index (I21) of the composition is from 0.5 to 15 g / 10 min.

[0070] In addition to a high melt index, the composition may have a density in the range of 0.890-0.930 g / cc (or 0.890-0.926 g / cc), a weight-average molecular weight (Mw) of 250,000 to 2,000,000 g / mol (or 400,000 to 1,600,000 g / mol), a molecular weight distribution (ratio of weight-average molecular weight to number-average molecular weight, Mw / Mn) of 7 to 40 (or 5 to 20), and / or Eta 0.1 The range is 75,000 to 3,500,000 Pa-sec (or 100,000 to 3,000,000 Pa-sec).

[0071] In the embodiments described herein, as measured by mortar tank testing, the composition may exhibit a mass loss of less than 3.5% (or less than 2.5% in some embodiments).

[0072] The compositions described herein may contain one or more optional additives. Additives include, but are not limited to, processing aids, acid neutralizers, UV stabilizers, hydrogen peroxide decomposers, alkyl scavengers, hindered amine stabilizers, multifunctional stabilizers, phosphites, antioxidants, processing stabilizers, metal deactivators, additives that improve oxidation or chlorine resistance, pigments or colorants, nucleating agents, fatty acid stearates, fluoroelastomers, fillers, and combinations thereof.

[0073] In the embodiments described herein, the compositions may contain one or more processing aids. In some embodiments, the processing aids may comprise one or more fluoropolymers. Without being bound by theory, it is believed that including one or more fluoropolymers in the compositions described herein improves the processability of the composition by reducing buildup at the extrusion die and lowering the apparent melt viscosity of the composition. Furthermore, including one or more fluoropolymers in the compositions described herein does not adversely affect the mechanical properties of the composition. Suitable fluoropolymers include, but are not limited to, vinylidene fluoride, hexafluoropropylene, trifluorochloroethylene, tetrafluoroethylene, perfluoroalkyl perfluorovinyl ethers, 1-hydrogenated pentafluoropropylene, 2-hydrogenated pentafluoropropylene, and combinations thereof. Other examples of suitable fluoropolymers include, but are not limited to, copolymers of vinylidene fluoride and one or more comonomers selected from hexafluoropropylene, trifluorochloroethylene, 1-hydrogenated pentafluoropropylene, and 2-hydrogenated pentafluoropropylene. Further examples of suitable fluoropolymers include, but are not limited to, copolymers of tetrafluoroethylene and one or more comonomers selected from hexafluoropropylene and vinylidene fluoride. In some instances, the fluoropolymer may be further blended with olefins (e.g., propylene) or polyethers (e.g., polyethylene oxide). In some embodiments, the fluoropolymer is selected from the group consisting of: vinylidene fluoride / hexafluoropropylene, vinylidene fluoride / hexafluoropropylene / tetrafluoroethylene, tetrafluoroethylene, tetrafluoroethylene / propylene, tetrafluoroethylene / propylene / vinylidene fluoride, or vinylidene fluoride / hexafluoropropylene / polyethylene oxide. In other embodiments, the fluoropolymer is selected from the group consisting of: vinylidene fluoride / hexafluoropropylene, vinylidene fluoride / hexafluoropropylene / tetrafluoroethylene, tetrafluoroethylene / propylene / vinylidene fluoride, or vinylidene fluoride / hexafluoropropylene / polyethylene oxide. In still other embodiments, the fluoropolymer is vinylidene fluoride / hexafluoropropylene / tetrafluoroethylene.

[0074] The fluoropolymers described herein may also possess one or more other properties. In some embodiments, the melting point of the fluoropolymer used in the compositions described herein may be from 100°C to 135°C, as measured by differential scanning calorimetry (DSC) according to ASTM D4591-07. In some embodiments, the density of the fluoropolymer used in the compositions described herein may be from 1.80 to 2.20 g / cc. The density may be determined according to ASTM D792. In some embodiments, the melt flow index (265°C; 5 kg) of the fluoropolymer used in the compositions described herein may be from 2.0 to 20.0 g / 10 min. The melt flow index (MFI) may be determined according to ASTM D1238 at 265°C, 5.0 kg. One or more fluoropolymers may be used in the composition such that the total fluoropolymer content is 50 to 5000 ppm, 100 to 3000 ppm, 150 to 2000 ppm, or 250 to 1000 ppm. Without being bound by theory, it is believed that incorporating one or more fluoropolymers into the compositions described herein can contribute to a more homogeneous blend during compounding and also contribute to better abrasion resistance by reducing the coefficient of friction at the surfaces of the compositions described herein.

[0075] The compositions described herein can be prepared by any suitable mixing means known in the art, including melt or dry / physical blending of the individual components. It should be understood that other suitable methods for blending the components may be used together. In some embodiments herein, the components may be blended under high shear conditions. For example, the components may be blended at shear rates greater than or equal to 5 / s, greater than or equal to 10 / s, greater than or equal to 20 / s, or greater than or equal to 50 / s. In other embodiments, the components may be blended at shear rates greater than or equal to 5 / s to less than or equal to 1000 / s. All individual values ​​and subranges greater than or equal to 5 / s and less than or equal to 1000 / s are included and disclosed herein. It should be understood that various combinations of shear rates may also be used (e.g., a shear rate of 5 / s for a period of time, and then a shear rate of 50 / s for another period of time).

[0076] The compositions described herein can be used to manufacture molded articles or one or more components thereof. Such articles can be single-layer or multi-layer articles, which can be obtained by using known conversion techniques suitable for obtaining the desired article, applying heat, pressure, or combinations thereof. Examples of suitable conversion techniques may include, for example, blow molding, co-extrusion blow molding, injection molding, injection stretch blow molding, compression molding, extrusion, pultrusion, calendering, and thermoforming. Molded articles may include, for example, pipes, pipe liners, pipe coatings (e.g., steel pipe coatings), blow-molded articles, injection-molded articles, compression-molded articles, drip irrigation tapes and tubes, films, sheets, fibers, profiles, and molded articles.

[0077] In some embodiments, the compositions described herein are particularly suitable for manufacturing durable pipes. The pipes may include single-layer pipes and multi-layer pipes, including multi-layer composite pipes. Pipes formed from the compositions described herein may also contain a suitable combination of additives and / or fillers designed for pipe applications. In other embodiments, the compositions described herein are highly suitable for manufacturing pipe linings.

[0078] The embodiments described herein can be further illustrated by the following non-limiting examples.

[0079] Test methods

[0080] Unless otherwise stated, use the following testing method.

[0081] density

[0082] The density of ethylene polymers was determined according to ASTM D792.

[0083] Melt Flow Index

[0084] The melt index, or I2, of ethylene polymers is determined according to ASTM D1238 at 190°C and 2.16 kg. The high-load melt index, or I21, of ethylene polymers is determined according to ASTM D1238 at 190°C and 21.6 kg.

[0085] Gel permeation chromatography

[0086] The chromatographic system consisted of a PolymerChar GPC-IR (Valencia, Spain) high-temperature GPC chromatograph equipped with a 4-capillary differential viscometer detector and an IR5 multi-fixed-wavelength infrared detector. A precision detector (Agilent 2-angle laser scattering detector, model 2040) was added to the system. A 15-degree angle of the light scattering detector was used for computational purposes. Data collection was performed using PolymerChar's "GPC One" software. The system was equipped with an online solvent degassing unit from Agilent.

[0087] The disc conveyor chamber and column chamber were operated at 150°C. Four Agilent “Mixed A” 30 cm 20-micron columns were used. The chromatographic solvent used was 1,2,4-trichlorobenzene containing 200 ppm of butylated hydroxytoluene (BHT). The solvent source was bubbled with nitrogen. The injection volume was 200 μL, and the flow rate was 1.0 mL / min.

[0088] For conventional molecular weight measurements, GPC column assemblies are calibrated using at least 20 narrow molecular weight distribution polystyrene standards (Agilent), wherein the molecular weights of these standards range from 580 to 8,400,000, and are arranged in a mixture of six “mixtures” with at least ten-fold intervals between individual molecular weights. Polystyrene standards are prepared by using 0.025 g in 50 mL of solvent for molecular weights equal to or greater than 1,000,000, and 0.05 g in 50 mL of solvent for molecular weights less than 1,000,000. The polystyrene standards are dissolved by gentle stirring at 80°C for 30 minutes. The peak molecular weights of the polystyrene standards are converted to polyethylene molecular weights using the following equation (as described in Williams and Ward, *Journal of Polymer Science*, *Polymer Letters*, 6,621 (1968)):

[0089] M 聚乙烯 =A×(M) 聚苯乙烯 ) B

[0090] Where M is the molecular weight, and for conventional GPC and three-detector main chain MW calculations, the value of A is approximately 0.41 (referencing the A value for SRM NBS1475, which yields a Mw of 52,000) and B equals 1.0. A third-order multi-top equation was used to fit the corresponding polyethylene equivalent calibration point. Data calculations were performed using GPC One software from Perimocha.

[0091] Dynamic mechanical spectrum (DMS)

[0092] The resin was compressed and molded into 25×3mm circular sheets at 20,000 lbs, in air, and at 190°C for six and a half minutes. The samples were then removed from the press and placed on a counter to cool.

[0093] Isothermal frequency scanning was performed using a TA Instruments Advanced Rheological Extension System (ARES) equipped with a 25 mm (diameter) parallel plate under nitrogen purging. The sample was placed on the plate and allowed to melt at 190 °C for five minutes. The plate was then closed to a 2 mm gap, the sample was trimmed (removing any excess sample extending beyond the circumference of the 25 mm diameter plate), and testing commenced. The method incorporates a built-in additional five-minute delay to allow for temperature equilibration. Experiments were performed at 190 °C in the frequency range of 0.1 to 100 rad / s. The strain amplitude was kept constant at 10%. At 0.1 rad / s (Eta... 0.1 The viscosity at this point can be calculated from this data and reported in Pa-sec.

[0094] Abrasion resistance test (mortar test)

[0095] A sand slurry test rig, similar to the one described in ISO-15527, was used for abrasion testing. The rig was 11 inches (depth) × 9 inches (inner diameter). It contained 10.2 kg of Alox 16 alumina gravel and 6.2 kg of water, filling the bottom 8 inches of the container. A 6-inch L × 6-inch W × 10 mm thick compression-molded sheet was cut into test pieces measuring 3.875 ft. (preferential) L × 1.25 inch W × 10 mm. The test pieces were attached to the bottom of a 10-inch long drive shaft, which rotated the test pieces 2 inches above the bottom of the rig at approximately 1,500 rpm. At least three samples were tested at room temperature for 90 minutes at 1,500 rpm. The test produced a noticeable but reproducible loss of mass on the test pieces. Fresh gravel and water were used for each test. The weight of each test piece was measured before and after the abrasion test. Perform the following calculations: Weight loss per test piece g = [Weight before grinding, g] - [Weight after grinding, g]; Average weight loss = [∑Weight loss per test piece, g] / [Number of measurements]; Weight loss % per test piece = [Weight loss per test piece (g) / Weight before grinding (g)] × 100%; Average weight loss % = [∑Weight loss %] / [Number of measurements]. The endpoints of the loss range are selected from the lowest and highest weight loss values.

[0096] Example

[0097] The following compositions are used in the examples described below.

[0098] Invention Example 1

[0099] Ultra-high molecular weight polyethylene (UHMWPE) has a weight-average molecular weight of 8,000,000 g / mol, a density of 0.925 g / cc, an intrinsic viscosity of 28 dL / g, and an average particle size D50 of 150 μm (UTEC). TM 6541, available from Braskem, Brazil, and thermoplastic polyolefin elastomers (INFUSE). TM9010 (density = 0.877 g / cc, melt flow index I2 = 0.5 g / 10 min, Mw / Mn = 2.6, available from Dow Chemical Company, USA) was blended at a weight ratio of 65:35 to form a composition. The composition was then compounded with 600 ppm of a fluoropolymer processing aid (melt flow index (265°C, 5 kg) of 10 g / 10 min (Dynamar FX5911, available from 3M Company, Inc., USA)) using a LabTech 26 mm twin-screw mixer at the following processing parameters to produce uniform pellets:

[0100] Barrel temperature: 275℃ flat temperature profile

[0101] Mold temperature: 280℃; flat temperature profile

[0102] Screw RPM: 130; Torque: 80%; Melting temperature: 280℃.

[0103] The properties of the composition (granules) are shown in Table 1 below. The composition was compressed and molded into 6" × 6" sheets (10 mm thick) and then cut into 3.875" × 1.25" test pieces for abrasion testing. Details of the compression molding procedure are described in ASTM D4703.

[0104] Invention Example 2

[0105] Ultra-high molecular weight polyethylene (UHMWPE) has a weight-average molecular weight of 8,000,000 g / mol, a density of 0.925 g / cc, an intrinsic viscosity of 28 dL / g, and an average particle size D50 of 150 μm (UTEC). TM 6541 (available from Blasco, Brazil), and thermoplastic polyolefin elastomers (INFUSE) TM 9010, density = 0.877 g / cc, melt flow index I2 = 0.5 g / 10 min, Mw / Mn = 2.6, available from Dow Chemical Company, USA, was blended at a weight ratio of 55:45 to form a composition. The composition was then mixed with 600 ppm of a fluoropolymer processing aid (melt flow index (265°C, 5 kg) of 10 g / 10 min (Dynamar FX5911, available from 3M Company, USA)) using a LabTech 26 mm twin-screw mixer at the following processing parameters to produce uniform pellets:

[0106] Barrel temperature: 275℃ flat temperature profile

[0107] Mold temperature: 280℃; flat temperature profile

[0108] Screw RPM: 130; Torque: 80%; Melting temperature: 280℃.

[0109] The properties of the composition (granules) are shown in Table 1 below. The composition was compressed and molded into 6" × 6" sheets (10 mm thick) and then cut into 3.875" × 1.25" test pieces for abrasion testing. Details of the compression molding procedure are described in ASTM D4703.

[0110] Invention Example 3

[0111] Ultra-high molecular weight polyethylene (UHMWPE) has a weight-average molecular weight of 8,000,000 g / mol, a density of 0.925 g / cc, an intrinsic viscosity of 28 dL / g, and an average particle size D50 of 150 μm (UTEC). TM 6541 (available from Blasco, Brazil), and thermoplastic polyolefin elastomers (INFUSE) TM 9010, density = 0.877 g / cc, melt flow index I2 = 0.5 g / 10 min, Mw / Mn = 2.6, available from Dow Chemical Company, USA, was blended at a weight ratio of 40:60 to form a composition. The composition was then mixed with 600 ppm of a fluoropolymer processing aid (melt flow index (265°C, 5 kg) of 10 g / 10 min (Dynamar FX5911, available from 3M Company, USA)) using a LabTech 26 mm twin-screw mixer at the following processing parameters to produce uniform pellets:

[0112] Barrel temperature: 275℃ flat temperature profile

[0113] Mold temperature: 280℃; flat temperature profile

[0114] Screw RPM: 130; Torque: 80%; Melting temperature: 280℃.

[0115] The properties of the composition (granules) are shown in Table 1 below. The composition was compressed and molded into 6" × 6" sheets (10 mm thick) and then cut into 3.875" × 1.25" test pieces for abrasion testing. Details of the compression molding procedure are described in ASTM D4703.

[0116] Invention Example 4

[0117] Ultra-high molecular weight polyethylene (UHMWPE) has a weight-average molecular weight of 8,000,000 g / mol, a density of 0.925 g / cc, an intrinsic viscosity of 28 dL / g, and an average particle size D50 of 150 μm (UTEC). TM 6541 (available from Blasco, Brazil), and thermoplastic polyolefin elastomers (ENGAGE) TM7280, density = 0.884 g / cc, melt flow index I2 = 0.50 g / 10 min, available from Dow Chemical Company, USA, was blended at a weight ratio of 65:35 to form a composition. The composition was then mixed with 600 ppm of a fluoropolymer processing aid (melt flow index (265°C, 5 kg) of 10 g / 10 min (Dynamar FX5911, available from 3M Company, USA)) using a LabTech 30 mm twin-screw mixer at the following processing parameters to produce uniform pellets:

[0118] Barrel temperature: 275℃ flat temperature profile

[0119] Mold temperature: 280℃; flat temperature profile

[0120] Screw RPM: 130; Torque: 80%; Melting temperature: 280℃.

[0121] The properties of the composition (granules) are shown in Table 1 below. The composition was compressed and molded into 6" × 6" sheets (10 mm thick) and then cut into 3.875" × 1.25" test pieces for abrasion testing. Details of the compression molding procedure are described in ASTM D4703.

[0122] Invention Example 5

[0123] Ultra-high molecular weight polyethylene (UHMWPE) has a weight-average molecular weight of 8,000,000 g / mol, a density of 0.925 g / cc, an intrinsic viscosity of 28 dL / g, and an average particle size D50 of 150 μm (UTEC). TM 6541 (available from Blasco, Brazil), and thermoplastic polyolefin elastomers (ENGAGE) TM 7387, density = 0.870 g / cc, melt flow index I2 = 0.50 g / 10 min, available from Dow Chemical Company, USA, was blended at a weight ratio of 65:35 to form a composition. The composition was then mixed with 600 ppm of a fluoropolymer processing aid (melt flow index (265°C, 5 kg) of 10 g / 10 min (Dynamar FX5911, available from 3M Company, USA)) using a LabTech 26 mm twin-screw mixer at the following processing parameters to produce uniform pellets:

[0124] Barrel temperature: 275℃ flat temperature profile

[0125] Mold temperature: 280℃; flat temperature profile

[0126] Screw RPM: 130; Torque: 80%; Melting temperature: 280℃.

[0127] The properties of the composition (granules) are shown in Table 1 below. The composition was compressed and molded into 6" × 6" sheets (10 mm thick) and then cut into 3.875" × 1.25" test pieces for abrasion testing. Details of the compression molding procedure are described in ASTM D4703.

[0128] Table 1: Composition Properties

[0129]

[0130] Comparison Examples

[0131] Comparison Example 1

[0132] Ultra-high molecular weight polyethylene (UHMWPE) has a weight-average molecular weight of 8,000,000 g / mol, a density of 0.925 g / cc, an intrinsic viscosity of 28 dL / g, and an average particle size D50 of 150 μm (UTEC). TM 6541 (available from Blasco, Brazil). The composition is compressed and molded into 6"×6" sheets (10mm thick), and then cut into 3.875"×1.25" test pieces for abrasion testing.

[0133] Table 2: Abrasion resistance and HLMI (or I21) test results

[0134] <![CDATA[ Loss characteristics in water at room temperature ]]> <![CDATA[ Material ]]> <![CDATA[HLMI or I 21 (g / 10 min)]]> Average weight loss (%) Invention Example 1 2.09 1.61 Invention Example 2 -- 1.35 Invention Example 3 -- 0.97 Invention Example 4 -- 1.48 Invention Example 5 -- 1.23 Comparison Example 1 0.00 2.31

[0135] As shown in Table 2, when compared with Comparative Example 1, the Invention Example exhibits higher abrasion resistance (i.e., lower average weight loss %). Furthermore, when compared separately with Comparative Example 1, the HLMI of Invention Example 1 shows improved processability due to its higher HLMI value.

Claims

1. An ethylene composition comprising a blend of the following: Ultra-high molecular weight polyethylene with an inherent viscosity of 5 to 50 dL / g. A thermoplastic polyolefin elastomer with a density of 0.850 to 0.900 g / cc, wherein the thermoplastic polyolefin elastomer comprises an ethylene / α-olefin multiblock copolymer, wherein the molecular weight distribution Mw / Mn of the ethylene / α-olefin multiblock copolymer is 1.0 to 3.5, and Optionally, fluoropolymers, The ethylene composition comprises 40 wt% to 65 wt% of ultra-high molecular weight polyethylene and 35 wt% to 60 wt% of thermoplastic polyolefin elastomer.

2. The composition according to claim 1, wherein the density of the ultra-high molecular weight polyethylene is 0.915 to 0.940 g / cc.

3. The composition according to any one of claims 1 to 2, wherein the ultra-high molecular weight polyethylene has a weight-average molecular weight greater than 1,000,000 g / mol.

4. The composition according to any one of claims 1 to 2, wherein the high-load melt index I21 of the blend is 0.1 to 40 g / 10 min.

5. The composition according to any one of claims 1 to 2, wherein the high-load melt index I21 of the blend is 0.1 to 20 g / 10 min.

6. The composition according to any one of claims 1 to 2, wherein the blend further comprises a fluoropolymer with a melt flow index of 2.0 to 20.0 g / 10 min, wherein the melt flow index is determined according to ASTM D1238 at 265°C and 5.0 kg.

7. The composition according to any one of claims 1 to 2, wherein the blend further comprises a fluoropolymer present in an amount of 50 to 5,000 ppm by weight of the composition.

8. A molded article comprising at least one component formed from the composition according to any one of claims 1 to 7.

9. The article according to claim 8, wherein the shaped article is a geomembrane.

Images