Flame retardant polymer composition

Abstract

The polymer composition includes an ethylene-based polymer, one or more of an ionomer and an acid copolymer, a flame retardant filler, and a maleic anhydride functionalized polyolefin. The polymer composition has an MAH product of 3 or greater.

Description

[Technical field]

[0001] The present disclosure relates to polymer compositions, and more particularly, to flame retardant polymer compositions.

[0002] Introduction Cables typically use polymer compositions around one or more conductors (i.e., photoconductors and / or conductors). In such cables, flame retardancy may not be an important property considered for a particular element of the cable, and thus the incorporation of flame retardant materials into the elements has been limited. Recently, however, flame retardancy standards have been refocused on target properties for the cable as a whole, rather than individual components. Such changes have placed a new emphasis on flame retardancy of cable components. For example, a buffer tube containing a conventional unfilled polyolefin or other buffer tube without flame retardant additives could result in flame retardancy-related failure of the entire cable, even if other components, such as the jacket, are flame retardant. Thus, to meet the new standards, the polymer compositions of these components must have a flame retardancy of 141 kilowatts per square meter ("kW / m") as measured according to ASTM E1354. 2 ") must demonstrate a cone calorific value of less than 100%.

[0003] The traditional method of adding flame retardancy to a polymer composition involves selecting a flexible base polyolefin (i.e., one with a low flexural modulus) and a flame-retardant filler for incorporation into the polyolefin. Utilizing this approach in certain applications is a challenging task for a variety of reasons. First, the flexural modulus of the cable components may be important, and incorporation of polyolefins with the typical low flexural modulus (e.g., 100 MPa to 200 MPa) used in flame-retardant polyolefins would result in components with inadequately low flexural modulus. Second, the cable components need to process well at high extrusion rates. However, halogen-free flame-retardant fillers ("HFFRs") are typically included at 60 wt. % or more, which reduces processability and final mechanical properties. Third, simply incorporating a flame-retardant filler is not sufficient to impart flame retardancy. If not properly compatibilized, the flame-retardant filler may aggregate within the polymer composition, resulting in minimal flame retardancy and reduced mechanical properties. Fourth, the incorporation of HFFR often reduces the tensile elongation properties of the polymer composition, although the percentage of elongation can also vary based on the base resin used. Typically, elongations greater than 20% are preferred for applications offered by high density polyethylene based polymer compositions, such as buffer tubes, and elongations greater than 175% are preferred for applications offered by ethylene-vinyl acetate based polymer compositions, such as jacketing.

[0004] The combination of ionomer and maleic anhydride grafted polymer is known in the art. For example, U.S. Patent No. 6,569,947(B1) ("'947 Patent") discloses a maleic anhydride modified ethylene polymer / ionomer / high density polyethylene blend useful in high impact resistance materials. However, such blends are only considered to be beneficial for improving impact properties, and no effect on flame retardancy was known.

[0005] In view of the above, 141 kW / m when measured according to ASTM E1354 2It is surprising to find polymer compositions that exhibit an elongation of less than 20% for high density polyethylene or greater than 175% for ethylene-vinyl acetate based compositions as measured according to cone calorimetry measurements ASTM D638, and exhibit no breaks or cracks when subjected to mandrel bend testing. Summary of the Invention

[0006] The inventors of the present application have reported a power output of 141 kW / m when measured according to ASTM E1354. 2 We have found polymer compositions that exhibit an elongation of greater than 20% for high density polyethylene or greater than 175% for ethylene-vinyl acetate based compositions as measured according to cone calorimetry, ASTM D638, and do not exhibit fracture when subjected to mandrel bend testing.

[0007] The present invention is the result of the discovery that the above properties can be achieved with a polymer composition comprising an ethylene-based polymer, a maleic anhydride functionalized polyolefin, one or more of an ionomer and an acid copolymer, and a flame retardant filler, and a MAH product of 3 or more of the polymer composition. Without being bound by theory, it is believed that the use of both the maleic anhydride functionalized polyolefin and one or more of an ionomer and an acid copolymer provides better dispersion of the metal hydroxide within the ethylene-based polymer, improving the flame retardant properties (i.e., a cone calorimetry of 141 kW / m 2 It is believed that the flame retardant filler bonds to the ethylene-based polymer such that the composition can withstand mandrel bending while the elongation (less than 20%) remains at 20% or greater than 175%. This result is surprising because the addition of fillers typically reduces the mechanical properties of a polymer composition, but the polymer compositions of the present disclosure can retain these properties as well as exhibit flame retardancy.

[0008] The present disclosure is particularly useful in forming components for use in fiber optic cables.

[0009] According to a first aspect of the present disclosure, a polymer composition includes an ethylene-based polymer, one or more of an ionomer and an acid copolymer, a flame retardant filler, and a maleic anhydride functionalized polyolefin, the polymer composition having a MAH product of 3 or greater.

[0010] According to a second aspect of the present disclosure, the polymer composition comprises 4 wt% to 16 wt% of a maleic anhydride functionalized polyolefin, based on the total weight of the polymer composition.

[0011] According to a third aspect of the present disclosure, the maleic anhydride-functionalized polyolefin comprises greater than or equal to 0.4 wt. % maleic anhydride, based on the total weight of the maleic anhydride-functionalized polyolefin.

[0012] According to a fourth aspect of the present disclosure, the maleic anhydride functionalized polyolefin has a density of 0.90 g / cc to 0.920 g / cc as measured according to ASTM D792.

[0013] According to a fifth aspect of the disclosure, the ethylene-based polymer has a bimodal molecular weight distribution, has a melt flow ratio greater than or equal to 70.0, and has a density greater than or equal to 0.945 g / cc, as measured according to ASTM D792.

[0014] According to a sixth embodiment of the present disclosure, the polymer composition comprises 18% to 50% by weight of an ethylene-based polymer, based on the total weight of the polymer composition.

[0015] According to a seventh aspect of the present disclosure, the polymer composition comprises 0.1 wt % to 10 wt % of an ionomer or an acid copolymer, based on the total weight of the polymer composition.

[0016] According to an eighth embodiment of the present disclosure, the polymer composition comprises 10 wt% to 80 wt% of a flame-retardant filler, based on the total weight of the polymer composition.

[0017] According to a ninth aspect of the present disclosure, the polymer composition comprises an ionomer, the ionomer being neutralized with one or more metal ions selected from the group consisting of Na, Zn, Li, K, Mg, and combinations thereof.

[0018] According to a tenth aspect of the present disclosure, a cable includes a conductor and a buffer tube disposed around the conductor, the buffer tube including the polymer composition according to any one of the first to ninth aspects. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] As used herein, the term "and / or," when used with a list of two or more items, means that any one of the listed items can be used by itself, or any combination of two or more of the listed items can be used. For example, if a composition is described as containing components A, B, and / or C, the composition can contain A alone, B alone, C alone, A and B in combination, A and C in combination, B and C in combination, or A, B, and C in combination.

[0020] Unless otherwise stated, all ranges are inclusive of the endpoints.

[0021] Test methods refer to the most current test method as of the priority date of this document unless a date is indicated with a two-digit number with a hyphen in the test method number. References to test methods include both a reference to the testing society and the test method number. Test method organizations are referred to 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 Norm, DIN refers to the Deutsches Institut fur Normung, and ISO refers to the International Organization for Standards.

[0022] As used herein, the term weight percent ("wt %"), unless otherwise specified, refers to the weight percentage that a component represents of the total weight of the polymer composition.

[0023] Melt index (I2) values ​​herein refer to values ​​determined according to ASTM method D1238 at 190 degrees Celsius (°C) using a mass of 2.16 kilograms (Kg) and are given in units of grams dissolved per 10 minutes ("g / 10 min").

[0024] Density values ​​herein refer to values ​​determined in accordance with ASTM D792 at 23° C. and are given in units of grams per cubic centimeter ("g / cc"). As used herein, Chemical Abstract Services Registry Number ("CAS#") refers to the unique identification number assigned to chemical compounds by the Chemical Abstract Service as of the priority date of this document.

[0025] Polymer Composition The present disclosure relates to a polymer composition. The polymer composition includes an ethylene-based polymer, one or more of an ionomer and an acid copolymer, a flame retardant filler, and a maleic anhydride-functionalized polyolefin. The polymer composition has an MAH product of 3 or more. As defined herein, the term "MAH product" is the weight percent of maleic anhydride-functionalized polyolefin (based on the total weight of the polymer composition) multiplied by the weight percent of maleic anhydride functionalization of the polyolefin (based on the total weight of the maleic anhydride-functionalized polyolefin). For example, if the polymer composition includes 10 wt% maleic anhydride-functionalized polyolefin and the polyolefin has 0.5 wt% maleic anhydride functionalization, the MAH product is 5. For example, the polymer composition may have an MAH product of 3 or more, or 3.5 or more, or 4.0 or more, or 4.5 or more, or 5.0 or more, or 10 or more, or 15 or more, or 20 or more, or 30 or more, or 40 or more, while simultaneously being 50 or less, or 40 or less, or 30 or less, or 20 or less, or 15 or less, or 10 or less, or 5.0 or less, or 4.5 or less, or 4.0 or less, or 3.5 or less.

[0026] The polymeric composition has a compressibility of 900 MPa or more, or 1,000 MPa or more, or 1,100 MPa or more, or 1,200 MPa or more, or 1,300 MPa or more, or 1,400 MPa or more, or 1,500 MPa or more, or 1,600 MPa or more, or 1,700 MPa or more, or 1,800 MPa or more, or 1,900 MPa or more, or 2,000 MPa or more, or 2,100 MPa or more, or 2,200 MPa or more, or 2,300 MPa or more, or 2,400 MPa or more, or 2,500 MPa or more, or 2,600 MPa or more, or 2,700 MPa or more, or 2,800 MPa or more, or 2,900 MPa or more, when measured in accordance with ASTM D790; At the same time, it may exhibit a flexural modulus of 3,000 MPa or less, or 2,900 MPa or less, or 2,800 MPa or less, or 2,700 MPa or less, or 2,600 MPa or less, or 2,500 MPa or less, or 2,400 MPa or less, or 2,300 MPa or less, or 2,200 MPa or less, or 2,100 MPa or less, or 2,000 MPa or less, or 1,900 MPa or less, or 1,800 MPa or less, or 1,700 MPa or less, or 1,600 MPa or less, or 1,500 MPa or less, or 1,400 MPa or less, or 1,300 MPa or less, or 1,200 MPa or less, or 1,100 MPa or less, or 1,000 MPa or less.

[0027] The polymer composition has a power output of 141 kW / m 2 For example, the polymer composition may exhibit a cone calorimetry of less than 140 kW / m 2 or less than 125kW / m 2 or less than 120kW / m 2 or less than 115kW / m 2 or less than 110kW / m 2 or less than 100kW / m 2 or less than 90kW / m 2 or less than 80kW / m 2 The following cone calorimetry measurements may be shown:

[0028] The polymeric composition may exhibit an elongation at break of greater than 20% when measured according to ASTM D638. For example, the polymeric composition may exhibit an elongation at break of 21% or more, or 22% or more, or 23% or more, or 24% or more, or 25% or more, or 26% or more, or 27% or more, or 28% or more, or 29% or more, or 30% or more, or 40% or more, or 50% or more, or 75% or more, or 100% or more, or 175% or more, or 180% or more, or 190% or more, or 200% or more, or 225% or more, or 250% or more, or 275% or more, or 300% or more, while simultaneously 350% or less, or 300% or less, or 250% or less, or 200% or less, or 150% or less, or 100% or less, or 50% or less, or 30% or less, when measured according to ASTM D638.

[0029] Ethylene-Based Polymers As noted above, the composition may include an ethylene-based polymer. As used herein, an "ethylene-based" polymer is a polymer in which greater than 50% by weight of the monomers are ethylene, although other comonomers may be used. An ethylene-based polymer is a polymer in which ethylene and one or more C3-C6 olefins, such as propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, and 1-octene, are copolymers of ethylene and one or more C3-C6 olefins, such as propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, and 1-octene. 20and an α-olefin comonomer. Other units of the ethylene-based polymer may be derived from one or more polymerizable monomers, including but not limited to polar monomers such as unsaturated esters. The unsaturated esters (i.e., polar monomers) may be alkyl acrylates, alkyl methacrylates, or vinyl carboxylates. The alkyl groups may have 1-8 carbon atoms or 1-4 carbon atoms. The carboxylate groups may have 2-8 carbon atoms or 2-5 carbon atoms. Examples of acrylates and methacrylates include, but are not limited to, ethyl acrylate, methyl acrylate, methyl methacrylate, t-butyl acrylate, n-butyl acrylate, n-butyl methacrylate, and 2-ethylhexyl acrylate. Examples of vinyl carboxylates include, but are not limited to, vinyl acetate, vinyl propionate, and vinyl butanoate. The ethylene-based polymer can 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, or 15% or 10% or less, or 5% or less, or 3% or less, or 1% or less, or 0% by weight, based on the total weight of the ethylene-based polymer, as measured using Nuclear Magnetic Resonance (NMR) or Fourier-Transform Infrared (FTIR) spectroscopy.

[0030] The ethylene-based polymer may have a monomodal or multimodal molecular weight distribution and may be used alone or in combination with one or more other types of ethylene-based polymers (e.g., a blend of two or more ethylene-based polymers differing from each other in monomer composition and content, catalyst preparation, molecular weight, molecular weight distribution, density, etc.). When a blend of ethylene-based polymers is used, the polymers may be blended by any in-reactor or post-reactor process. The term "multimodal polymer" refers to a polymer characterized by having at least two distinct peaks in a gel permeation chromatography (GPC) chromatogram showing the molecular weight distribution of the composition. Thus, the generic term multimodal polymer includes bimodal polymers having two major 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.

[0031] The ethylene-based polymer has an ethylene content of 50% by weight or more, 60% by weight or more, 70% by weight or more, 80% by weight or more, 85% by weight or more, 90% by weight or more, or 91% by weight or more, or 92% by weight or more, or 93% by weight or more, or 94% by weight or more, or 95% by weight or more, or 96% by weight or more, or 97% by weight or more, or 97.5% by weight or more, or 98% by weight or more, as measured using nuclear magnetic resonance (NMR) or Fourier transform infrared (FTIR) spectroscopy. % or more, or 99% or more, while at the same time comprising 99.5% or less, or 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 by weight of ethylene monomer.

[0032] The polymer composition may comprise 18% to 50% by weight of the ethylene-based polymer. For example, the polymer composition comprises 18% 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 by weight, and at the same time 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 by weight of the ethylene-based polymer, based on the total weight of the polymer composition.

[0033] The ethylene-based polymer has a melt flow ratio ("MFR") of 70.0 or greater. The term "melt flow ratio" refers to the ratio of the melt index of a polymer, and is defined as the ratio of the high load metal index (IFR) of a polymer, as measured at 190°C according to ASTM D1238-10. 21 ) divided by the melt index (I2) of the polymer. The MFR of the ethylene-based polymer can be 70 or more, or 80 or more, or 90 or more, or 100 or more, or 110 or more, or 120 or more, while simultaneously being 130 or less, or 120 or less, or 110 or less, or 100 or less, or 90 or less, or 80 or less.

[0034] The density of the ethylene polymer, as measured by ASTM D792, is 0.910 g / cc or greater, or 0.915 g / cc or greater, or 0.920 g / cc or greater, or 0.925 g / cc or greater, or 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. , while at the same time being 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, or 0.930 g / cc or less, or 0.925 g / cc or less, or 0.920 g / cc or less, or 0.915 g / cc or less. Generally, ethylene-based polymers having a density between 0.93 g / cc and 0.97 g / cc are referred to as "high density polyethylene" or "HDPE".

[0035] For example, the ethylene-based polymer can have a weight average molecular weight of 100,000 grams / mole ("g / mol") or more, or 125,000 g / mol or more, or 150,000 g / mol or more, or 175,000 g / mol or more, or 200,000 g / mol or more, or 225,000 g / mol or more, while simultaneously being 250,000 g / mol or less, or 225,000 g / mol or less, or 200,000 g / mol or less, or 175,000 g / mol or less, or 150,000 g / mol or less, or 125,000 g / mol or less, as measured by gel permeation chromatography.

[0036] In a bimodal example, the ethylene-based polymer comprises a low molecular weight fraction and a high molecular weight fraction. In such an example, the ethylene-based polymer may comprise a high molecular weight fraction in an amount of 40 wt% or more, or 42 wt% or more, or 44 wt% or more, or 46 wt% or more, or 47 wt% or more, or 50 wt% or more, or 52 wt% or more, or 54 wt% or more, or 56 wt% or more, or 58 wt% or more, while at the same time, 60 wt% or less, or 58 wt% or less, or 56 wt% or less, or 54 wt% or less, or 52 wt% or less, or 50 wt% or less, or 48 wt% or less, or 46 wt% or less, or 44 wt% or less, or 42 wt% or less, based on the total weight of the ethylene-based polymer. It is understood that the low molecular weight fraction is present in the ethylene-based polymer in the opposite weight % to the high molecular weight fraction.

[0037] The high molecular weight fraction of the ethylene-based polymer has a density of 0.917 g / cc to 0.929 g / cc. For example, the high molecular weight fraction can have a density of 0.917 g / cc or more, or 0.919 g / cc or more, or 0.921 g / cc or more, or 0.923 g / cc or more, or 0.925 g / cc or more, while at the same time having a density of 0.927 g / cc or less, or 0.925 g / cc or less, or 0.923 g / cc or less, or 0.921 g / cc or less, or 0.919 g / cc or less, as measured according to ASTM D792.

[0038] The high molecular weight fraction of ethylene-based polymers has a high load melt index (I 21 For example, the high molecular weight component has a molecular weight of 0.85 dg / min or more, or 0.90 dg / min or more, or 1.00 dg / min or more, or 1.20 dg / min or more, or 1.40 dg / min or more, or 1.60 dg / min or more, or 1.80 dg / min or more, or 2.00 dg / min or more, or 2.20 dg / min or more, or 2.40 dg / min or more, or 2.60 dg / min or more, or 2.80 dg / min or more, or 3.00 dg / min or more, or 3.20 dg / min or more, or 3.40 dg / min or more, or 3.60 dg / min or more, or 3.80 dg / min or more, while and at the same time a high load melt index (I ) of 4.00 dg / min or less, or 3.80 dg / min or less, or 3.60 dg / min or less, or 3.40 dg / min or less, or 3.20 dg / min or less, or 3.00 dg / min or less, or 2.80 dg / min or less, or 2.60 dg / min or less, or 2.40 dg / min or less, or 2.20 dg / min or less, or 2.00 dg / min or less, or 1.80 dg / min or less, or 1.60 dg / min or less, or 1.40 dg / min or less, or 1.20 dg / min or less, or 1.00 dg / min or less, or 0.90 dg / min or less. 21 ).

[0039] The high molecular weight component of the ethylene-based polymer has a weight average molecular weight of 200,000 g / mol or more, or 225,000 g / mol or more, or 250,000 g / mol or more, or 275,000 g / mol or more, or 300,000 g / mol or more, or 325,000 g / mol or more, or 350,000 g / mol or more, or 375,000 g / mol or more, while simultaneously being 400,000 g / mol or less, or 375,000 g / mol or less, or 350,000 g / mol or less, or 325,000 g / mol or less, or 300,000 g / mol or less, or 275,000 g / mol or less, or 250,000 g / mol or less, or 225,000 g / mol or less, as measured by gel permeation chromatography.

[0040] Ionomers and Acid Copolymers The polymer composition includes one or more of an ionomer and an acid copolymer. As used herein, the term "ionomer" refers to a partially or fully neutralized acid copolymer. As used herein, the term "acid copolymer" refers to a copolymer including repeat units derived from ethylene and 1% to 50% by weight of an acidic comonomer, such as acrylic acid, methacrylic acid, ethacrylic acid, or a combination thereof, based on the total weight of the acid copolymer. For example, the acid copolymer may comprise 0.5% or more, or 1% or more, or 2% or more, or 3% or more, or 4% or more, or 5% or more, or 10% or more, or 20% or more, or 30% or more, or 40% or more, while simultaneously comprising 50% or less, or 40% or less, or 30% or less, or 20% or less, or 10% or less, or 5% or less, or 4% or less, or 3% or less, or 2% or less, or 1% or less by weight of acidic comonomer, based on the total weight of the acid copolymer.

[0041] The ionomers may contain up to 35% by weight of optional comonomers, based on the total weight of the ionomer. Potential comonomers include carbon monoxide, sulfur dioxide, acrylonitrile, maleic anhydride, maleic acid diesters, maleic acid, maleic acid monoesters, itaconic acid, fumaric acid, fumaric acid monoesters, salts of these acids, glycidyl acrylate, glycidyl methacrylate, and glycidyl vinyl ether, methyl acrylate, ethyl acrylate, isopropyl acrylate, butyl acrylate, pentyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, and butyl methacrylate, pentyl methacrylate, or combinations thereof, where the alkyl groups may be linear or branched.

[0042] Ionomers may have a wide range of neutralization degrees. For example, ionomers may be neutralized 0.1% or more, or 1% or more, or 10% or more, or 15% by weight or more, or 20% or more, or 30% or more, or 40% or more, or 50% or more, or 60% or more, or 70% or more, or 80% or more, or 90% or more, while simultaneously 100% or less, or 90% or less, or 80% or less, or 70% or less, or 60% or less, or 50% or less, or 40% or less, or 30% or less, or 20% or less, or 15% by weight or less, or 10% or less, or 5% or less, based on the total acid content. Ionomers may be neutralized using one or more metal ions. The metal ions may be monovalent, divalent, trivalent, multivalent, or combinations thereof. Examples of suitable metal ions include Li, Na, Ag, Hg, Cu, Be, Mg, Ca, Sr, Ba, Cd, Sn, Pb, Fe, Co, Zn, Ni, Al, Sc, Hf, Ti, Zr, Ce, K, Na, and combinations thereof. When the metal ion is multivalent, complexing agents such as stearate, oleate, salicylate, and phenolate radicals can be included.

[0043] The ionomer may be a blend of an ionomer having greater than 20% neutralization with, for example, a second ethylene acid copolymer to achieve a desired degree of neutralization. For example, the ionomer may comprise 1% to 50% by weight of the acid copolymer disclosed above.

[0044] Examples of commercially available ionomers include SURLYN™ ionomers available from The Dow Chemical Company, Midland, MI, USA. Examples of commercially available acid copolymers include NUCREL™ 0411HS acid copolymers from Dow Chemical, Midland, Michigan.

[0045] The polymer composition comprises 1 wt% to 10 wt% of an ionomer, based on the total weight of the polymer composition. For example, the polymer composition comprises 1 wt% or more, or 2 wt% or more, or 3 wt% or more, or 4 wt% or more, or 5 wt% or more, or 6 wt% or more, or 7 wt% or more, or 8 wt% or more, or 9 wt% or more, while simultaneously comprising 10 wt% or less, or 9 wt% or less, or 8 wt% or less, or 7 wt% or less, or 6 wt% or less, or 5 wt% or less, or 4 wt% or less, or 3 wt% or less, or 2 wt% or less of one or more ionomers, based on the total weight of the polymer composition.

[0046] The polymer composition comprises 1 wt% to 10 wt% of the acid copolymer, based on the total weight of the polymer composition. For example, the polymer composition comprises 1 wt% or more, or 2 wt% or more, or 3 wt% or more, or 4 wt% or more, or 5 wt% or more, or 6 wt% or more, or 7 wt% or more, or 8 wt% or more, or 9 wt% or more, while simultaneously comprising 10 wt% or less, or 9 wt% or less, or 8 wt% or less, or 7 wt% or less, or 6 wt% or less, or 5 wt% or less, or 4 wt% or less, or 3 wt% or less, or 2 wt% or less of one or more acid copolymers, based on the total weight of the polymer composition.

[0047] Maleic Anhydride Functionalized Polyolefins The polymer composition comprises a maleic anhydride functionalized polyolefin. As used herein, the term "maleic anhydride functionalized" refers to a polyolefin that has been modified to incorporate maleic anhydride monomer. The maleic anhydride functionalized polyolefin may be formed by copolymerizing maleic anhydride monomer with ethylene and other monomers, if present, to prepare an interpolymer having maleic anhydride incorporated into the polymer backbone. Additionally or alternatively, the maleic anhydride may be graft polymerized onto the polyolefin. The maleic anhydride functionalized polyolefin may be any of the ethylene-based polymers described above.

[0048] The maleic anhydride functionalized polyolefin may have a density of 0.87 g / cc or more, or 0.88 g / cc or more, or 0.89 g / cc or more, or 0.90 g / cc or more, or 0.91 g / cc or more, or 0.92 g / cc or more, or 0.93 g / cc or more, or 0.94 g / cc or more, or 0.95 g / cc or more, 0.96 g / cc or more, while simultaneously being 0.97 g / cc or less, or 0.965 g / cc or less, or 0.96 g / cc or less, or 0.95 g / cc or less, or 0.94 g / cc or less, or 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, or 0.88 g / cc or less, or 0.87 g / cc or less, as measured by ASTM D792.

[0049] The maleic anhydride functionalized polyolefin may have a viscosity of 1 g / 10 min or more, or 2 g / 10 min or more, or 3 g / 10 min or more, or 4 g / 10 min or more, or 5 g / 10 min or more, or 6 g / 10 min or more, or 7 g / 10 min or more, or 8 g / 10 min or more, or 9 g / 10 min or more, or 10 g / 10 min or more, or 11 g / 10 min or more, or 12 g / 10 min or more, or 13 g / 10 min or more, or 14 g / 10 min or more, or 15 g / 10 min or more, or 16 g / 10 min or more, or 17 g / 10 min or more, or 18 g / 10 min or more, or 19 g / 10 min or more, while simultaneously being 20 g / 10 min or less, or has a melt flow index of 19 g / 10 min or less, or 18 g / 10 min or less, or 17 g / 10 min or less, or 16 g / 10 min or less, or 15 g / 10 min or less, or 14 g / 10 min or less, or 13 g / 10 min or less, or 12 g / 10 min or less, or 11 g / 10 min or less, or 10 g / 10 min or less, or 9 g / 10 min or less, or 8 g / 10 min or less, or 7 g / 10 min or less, or 6 g / 10 min or less, or 5 g / 10 min or less, or 4 g / 10 min or less, or 3 g / 10 min or less, or 2 g / 10 min or less. Melt index is measured at 190° C. and 2.16 kg according to ASTM D1238.

[0050] The maleic anhydride functionalized polyolefin may have a maleic anhydride content of 0.25 wt% or more, or 0.50 wt% or more, or 0.75 wt% or more, or 1.00 wt% or more, or 1.25 wt% or more, or 1.50 wt% or more, or 1.75 wt% or more, or 2.00 wt% or more, or 2.25 wt% or more, or 2.50 wt% or more, or 2.75 wt% or more, while simultaneously being 3.00 wt% or less, 2.75 wt% or less, or 2.50 wt% or less, or 2.25 wt% or less, or 2.00 wt% or less, or 1.75 wt% or less, or 1.50 wt% or less, or 1.25 wt% or less, or 1.00 wt% or less, or 0.75 wt% or less, or 0.5 wt% or less, based on the total weight of the maleic anhydride functionalized polyolefin. The maleic anhydride concentration is determined by titration analysis. Titration analysis is performed by utilizing the dried resin and titrating with 0.02N KOH to determine the amount of maleic anhydride. The dried polymer is titrated by dissolving 0.3-0.5 grams of maleic anhydride functionalized polyolefin in approximately 150 mL of refluxing xylene. After complete dissolution, deionized water (4 drops) is added to the solution and the solution is refluxed for 1 hour. 1% thymol blue (a few drops) is then added to the solution and the solution is titrated with 0.02N KOH in ethanol as indicated by the formation of a purple color. The solution is then back titrated with a solution of 0.05N HCl in isopropanol to a yellow endpoint.

[0051] The polymer composition may comprise 4 wt% or more, or 5 wt% or more, or 6 wt% or more, or 7 wt% or more, or 8 wt% or more, or 9 wt% or more, or 10 wt% or more, or 11 wt% or more, or 12 wt% or more, or 13 wt% or more, or 14 wt% or more, or 15 wt% or more, or 16 wt% or more, or 17 wt% or more, while simultaneously 18 wt% or less, or 17 wt% or less, or 16 wt% or less, or 15 wt% or less, or 14 wt% or less, or 13 wt% or less, or 12 wt% or less, or 11 wt% or less, or 10 wt% or less, or 9 wt% or less, or 8 wt% or less, or 7 wt% or less, or 6 wt% or less, or 5 wt% or less, or 4 wt% or less of maleic anhydride functionalized polyolefin, based on the total weight of the polymer composition.

[0052] An example of a suitable commercially available maleic anhydride functionalized polyolefin is AMPLIFY™ GR208, available from The Dow Chemical Company, Midland, Mich., USA.

[0053] Flame retardant filler The polymer composition includes a flame retardant filler. The flame retardant of the polymer composition may inhibit, suppress, or delay the development of a flame. Examples of flame retardants suitable for use in the polymer composition include, but are not limited to, metal hydroxides, metal carbonates, red phosphorus, silica, alumina, aluminum trihydroxide, magnesium hydroxide, titanium oxide, carbon nanotubes, talc, clay, organically modified clay, calcium carbonate, zinc borate, antimony trioxide, wollastonite, mica, ammonium octamolybdate, frit, hollow glass microspheres, expandable compounds, expandable graphite, and combinations thereof. Specifically, the halogen-free flame retardant may be selected from the group consisting of aluminum hydroxide, magnesium hydroxide, calcium carbonate, and combinations thereof. The flame retardant may optionally be surface-treated (coated) with a saturated or unsaturated carboxylic acid having 8 to 24 carbon atoms or 12 to 18 carbon atoms, or a metal salt of the acid. Exemplary surface treatments are described in U.S. Patent No. 4,255,303, U.S. Patent No. 5,034,442, U.S. Patent No. 7,514,489, U.S. Patent Application Publication No. 2008 / 0251273, and WO 2013 / 116283. Alternatively, the acid or salt can simply be added to the composition in a similar amount, rather than using a surface treatment procedure. Other surface treatments known in the art, including silanes, titanates, phosphates, and zirconates, can also be used.

[0054] Examples of commercially available flame retardants suitable for use in the polymer composition include, but are not limited to, APYRAL™ 40 CD aluminum hydroxide available from Nabaltec AG, MAGNIFIN™ H5 magnesium hydroxide available from Magnifin Magnesiprodukte GmbH&Co KG, Microcarb 95T ultramicronized and treated calcium carbonate available from Reverte, and combinations thereof.

[0055] The polymer composition may comprise 10 wt% or more, or 20 wt% or more, or 22 wt% or more, or 24 wt% or more, or 26 wt% or more, or 28% or more, or 30 wt% or more, or 32 wt% or more, or 34 wt% or more, or 36 wt% or more, or 38% or more, or 40 wt% or more, or 42 wt% or more, or 44 wt% or more, or 46 wt% or more, or 48% or more, or 50 wt% or more, or 52 wt% or more, or 54 wt% or more, or 56 wt% or more, or 58% or more, or 60 wt% or more, or 62 wt% or more, or 64 wt% or more, or 66 wt% or more, or 68% or more, or 70 wt% or more, or 72 wt% or more, or 74 wt% or more, or 76 wt% or more, or 78% or more, while the same Sometimes, it may contain a flame retardant filler in a concentration by weight of 80% or less, or 78% or less, or 76% or less, or 74% or less, or 72% or less, or 70% or less, or 68% or less, or 66% or less, or 64% or less, or 62% or less, or 60% or less, or 58% or less, or 56% or less, or 54% or less, or 52% or less, or 50% or less, or 48% or less, or 46% or less, or 44% or less, or 42% or less, or 40% or less, or 38% or less, or 36% or less, or 34% or less, or 32% or less, or 30% or less, or 28% or less, or 26% or less, or 24% or less, or 22% or less, or 20% or less.

[0056] Additives The polymeric composition may include additional additives in the form of antioxidants, crosslinking coagents, cure accelerators and char retarders, processing aids, coupling agents, ultraviolet stabilizers (including UV absorbers), antistatic agents, additional nucleating agents, slip agents, lubricants, viscosity modifiers, tackifiers, antiblocking agents, surfactants, extender oils, acid scavengers, anti-drip agents (e.g., ethylene vinyl acetate), and metal deactivators. The polymeric composition may include 0.01% to 20% by weight of one or more of the additional additives.

[0057] UV light stabilizers may include hindered amine light stabilizers (HALS) and UV light absorber (UVA) additives. Exemplary UVA additives include benzotriazole types such as TINUVIN 326™ and TINUVIN 328™ light stabilizers available from Ciba, Inc. Blends of HAL's and UVA additives are also effective.

[0058] Antioxidants include hindered phenols such as tetrakis[methylene(3,5-di-tert-butyl-4-hydroxyhydro-cinnamate)]methane; bis[(beta-(3,5-di-tert-butyl-4-hydroxybenzyl)methylcarboxyethyl)]-sulfide, 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)-hydrocinnamate; tris(2,4-di-tert-butylphenyl)phosphatase. phosphites and phosphonites such as sphite and di-tert-butylphenyl-phosphonite; thio compounds such as dilauryl thiodipropionate, dimyristyl thiodipropionate, and distearyl thiodipropionate; various siloxanes; polymeric 2,2,4-trimethyl-1,2-dihydroquinoline, n,n'-bis(1,4-dimethylpentyl-p-phenylenediamine), alkylated diphenylamines, 4,4'-bis(alpha,alpha-dimethylbenzyl)diphenylamine, diphenyl-p-phenylenediamine, mixed di-aryl-p-phenylenediamines, and other hindered amine antidegradants or stabilizers.

[0059] 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, erucamide, or N,N'-ethylene bis-stearamide; polyethylene waxes; oxidized polyethylene waxes; polymers of ethylene oxide; copolymers of ethylene oxide and propylene oxide; vegetable waxes; petroleum waxes; non-ionic surfactants; silicone fluids, polysiloxanes, fluoropolymers, and / or fluoroelastomers.

[0060] combination The polymer composition can be added to a batch or continuous mixer for melt blending. The components can be added in any order or by first preparing one or more masterbatches to blend with the other components. The melt blending can be done at a temperature higher than the highest melting point polymer but lower than the maximum compounding temperature of 285°C. The melt blended composition can then be delivered to an extruder or injection molding machine, passed through a die to be formed into the desired article, or converted to pellets, tape, strip or film, or other forms for storage or preparation of the material to feed the next molding or processing step. Optionally, if formed into pellets or some similar configuration, the pellets or the like can be coated with an anti-blocking agent to facilitate handling during storage.

[0061] Examples of compounding equipment that can be used include an internal batch mixer, a continuous single or twin screw mixer, or a kneading continuous extruder. The type of mixer utilized and the operating conditions of the mixer affect the properties of the composition, such as viscosity, volume resistivity, and extrusion surface smoothness.

[0062] cable The polymer composition may be utilized in a cable. In some examples, the cable may be a coated conductor. In other examples, the cable may be a fiber optic cable. In an example of a coated conductor, the coated conductor includes a conductor and a coating on the conductor, the coating including the polymer composition. The polymer composition is disposed at least partially around the conductor to produce the coated conductor. The conductor may comprise a conductive metal or an optically transparent structure.

[0063] In the example of a fiber optic cable, the cable includes a conductor and the polymer composition is disposed around the conductor. The polymer composition may be in the form of a buffer tube, one or more jacket layers on the cable, and / or other components in the cable. The conductor may include optical fibers or other transparent components. The fiber optic cable may be a "loose buffer tube" design where the buffer tube is radially disposed around a central strength member while rotating helically relative to the buffer tube along the axial length of the optical fibers. One or more conductors may be disposed within the buffer tube such that the buffer tube is disposed around the conductor. The buffer tube may comprise, consist of, or consist essentially of the polymer composition. Thus, the buffer tube may be a polymer tube. The buffer tube is optionally filled with an optical cable grease or gel. Gel and grease compounds may include hydrocarbon-based greases incorporating hydrocarbon oils and / or polymer-based greases using low viscosity polymers formulated with hydrocarbon oils. EXAMPLES

[0064] material The following materials were used in the examples:

[0065] EVA is an ethylene vinyl acetate ("EVA") copolymer having 28% by weight vinyl acetate based on the total weight of the copolymer and is commercially available from The Dow Chemical Company (Midland, Mich., USA).

[0066] ATH is aluminum trihydroxide commercially available as APYRAL™ 40 CD from Brenntag, Essen, Germany.

[0067] MDH is magnesium hydroxide having a density of 2.36 g / cc and is commercially available as MAGNIFIN™ H5 from Magnifin Magnesiprodukte GmbH & Co KG (Austria).

[0068] HDPE1 is UNIPOL™ II bimodal polyethylene with hexene comonomer, density of 0.95 g / cc, and melt index (I2) of 0.5 g / 10 min at 190° C. manufactured by The Dow Chemical Company (Midland, MI, USA).

[0069] HDPE2 is a bimodal polyethylene with hexane comonomer, a density of 0.955 g / cc, and a melt index (I2) of 0.3 g / 10 min at 190° C., commercially available as DGDA-1310NT™ from The Dow Chemical Company, Midland, MI, USA.

[0070] MAH-g-LLDPE (1) is a maleic anhydride grafted plastomer having a density of 0.902 g / cc, a melt index of 3.3 g / 10 min, and a maleic anhydride content of 0.45 wt. %, commercially available from The Dow Chemical Company (Midland, MI, USA).

[0071] MAH-g-POE is a maleic anhydride grafted LLDPE having a density of 0.875 g / cc, a melt index of 1.3 g / 10 min, and a maleic anhydride content of 0.90 wt. %, commercially available from The Dow Chemical Company (Midland, MI, USA).

[0072] MAH-g-HDPE is a maleic anhydride grafted HDPE having a density of 0.958 g / cc, a melt index of 2.0 g / 10 min, and a maleic anhydride content of 1.35 wt %, commercially available from The Dow Chemical Company (Midland, MI, USA).

[0073] MAH-g-LLDPE (2) is commercially available from The Dow Chemical Company (Midland, MI, USA) and has a viscosity of 0.912 g / cm3 The maleic anhydride grafted LLDPE has a density of 2.2 g / 10 min, a melt index of 2.1 g / 10 min, and a maleic anhydride content of 2.4 wt. %.

[0074] MAA Ionomer 1 is a Zn-neutralized methacrylic acid-ethylene copolymer having 15 wt. % methacrylic acid units, a density of 0.952 g / cc, and a melt index of 14 g / 10 min, commercially available from The Dow Chemical Company (Midland, MI, USA).

[0075] MAA Ionomer 2 is a Mg-neutralized methacrylic acid-ethylene copolymer having 19 wt% methacrylic acid units, a density of 0.952 g / cc, and a melt index of 6 g / 10 min manufactured by The Dow Chemical Company (Midland, MI, USA).

[0076] PDMS is a polydimethylsiloxane oil with a density of 0.977 g / cc, a viscosity of 60,000 centistokes, and is commercially available from The Dow Chemical Company (Midland, Mich., USA).

[0077] AO1 is a sterically hindered phenolic antioxidant having the chemical name pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), commercially available as IRGANOX 1010™ from BASF, Ludwigshafen, Germany.

[0078] AO2 is dioctadecyl 3,3'-thiodipropionate, commercially available as NAUGARD™ DSTDP from Addivant (Danbury, CT, USA).

[0079] DFDA is a halogen-free, flame retardant filled polyolefin material having a density of 1.50 g / cc and is commercially available as UNIGARD™ DFDA-1638NT from The Dow Chemical Company (Midland, Mich., USA).

[0080] The VLDPE is an ethylene-butene copolymer having a density of 0.901 g / cc and a melt index of 5.2 g / 10 min, commercially available as FLEXOMER™ DFDB-9042NT from The Dow Chemical Company, Midland, Mich., USA.

[0081] The ACP is an acid copolymer having 4% by weight methacrylic acid units, a melt index (I2) of 11 g / 10 min, and is commercially available from Dow Chemical (Midland, Michigan) as NUCREL™ 0411 HS acid copolymer.

[0082] Sample preparation Samples were prepared by melt blending in a BRABENDER™ mixer. All samples (except commercial samples) were mixed in a lab-scale 250 gram BRABENDER™ mixing bowl with a 250 gm capacity using a BANBURY™ type mixing blade with the settings shown in Table 1. After melt mixing, the molten material was removed and placed between biaxially oriented polyethylene terephthalate sheets and pressed into a sheet at 23° C. using a WABASH™ compression molding press. The material was then cut into strips so that it could be pelletized using a BERLYN™ pelletizing unit.

[0083] The pellets from each sample were then used to make tape samples using a BRABENDER™ tape extruder at the conditions shown in Table 2. The tapes had dimensions of 1.58 mm thickness and approximately 51 mm width. Type 4a dogbone samples were die cut in the machine direction for tensile and elongation measurements according to ASTM D638. [Table 1] [Table 2]

[0084] Test Method Tensile and Elongation Five Type 4 dogbone specimens for each sample were die cut in the machine direction from the tape samples. Tensile and elongation were completed on an INSTRON™ 4201 tensile tester using a 100 lb load cell at a strain rate of 2 in / min according to ASTM D638.

[0085] Flexural modulus Plaques for flexural modulus were compression molded in a 3.18 mm, 20 cm x 20 cm steel mold at 180° C. Samples were die cut to dimensions of approximately 3 cm x 1 cm. Testing was performed according to ASTM D790 at a crosshead speed of 1.27 mm / min and a support span of 51 mm.

[0086] Cone Calorimetry Samples for cone calorimetry testing were prepared by compression molding and then die cutting to a size of 100 mm x 100 mm x 3 mm. 2 Testing was completed in accordance with ASTM E1354 with the heat flux set at 0.5°C. Samples were tested without a grid and values ​​reported are the average of 2-3 samples. Calorimetric results are expressed as Peak Heat Release Rate ("PHRR").

[0087] Combustion Test The flame tests were carried out according to Underwriter's Laboratory standard 94, standard for the safety of flammability of plastic materials for parts of equipment and instruments. Vertical burning was measured according to the test standard on samples of 125 mm x 13 mm cut from plaques of 3.175 mm thickness. According to the test, V-2 indicates that the vertical sample stops burning within 30 seconds and dripping of burning particles is expected. V-0 indicates that burning stops within 10 seconds on the vertical specimens and dripping of particles is expected unless they are flared up.

[0088] Extruded Tape / Mandrel Bend Test The tape samples were wrapped completely around a mandrel having a diameter of about 7.7 mm and held in that position for a minimum of 10 seconds. Any kinks or breaks were recorded for each sample.

[0089] result Table 3 shows the compositions of Comparative Examples ("CE") 1-13, and Table 4 shows the mechanical properties and combustion performance data for each of the Comparative Examples. Table 5 shows the Examples of the Invention ("IE") and the mechanical properties and combustion performance data for each. In Tables 3-5, the term "NM" stands for not measured. [Table 3] [Table 4] [Table 5]

[0090] Referring now to Tables 3 and 4, CE1-3 suggest that the incorporation of MAH-g-POE or ionomer alone is not sufficient to produce a polymer composition with the desired mechanical and burn properties. For example, CE2 exceeds the elongation at break of an EVA-based composition. CE4 represents a typical commercial HFFR jacket compound with no ionomer and a low MAH product. CE5, CE6, and CE8-11 all demonstrate that the polymer composition cannot meet the minimum property requirements when the MAH product is less than 3 despite including maleic anhydride functionalized polyolefin and an ionomer or acid copolymer. CE12 demonstrates that a composition with a MAH product of 0 does not meet the required properties. CE13 demonstrates that the polymer composition cannot meet the minimum requirements when it does not include both an ionomer and a maleic anhydride functionalized polyolefin.

[0091] Referring now to Table 5, IE1-10 demonstrate that a polymer composition comprising an ethylene-based polymer, one or more of an ionomer and an acid copolymer, a flame retardant filler, and a maleic anhydride functionalized polyolefin, exhibiting a MAH product of 3 or greater, can meet all of the desired properties. As can be seen, the calorific values ​​of IE1-IE8 are all greater than 141 kW / m 2 The IE6 and IE7 achieved a V-0 flammability rating, which is 141 kW / m 2 It is suggested that the PHRR of the polymer composition can be achieved with a wide variety of different maleic anhydride functionalized polyolefins, flame retardant fillers, ionomers, and ethylene-based polymers and still achieve the desired properties. Furthermore, IE1-9 demonstrate that the mechanical properties are met regardless of whether the polymer composition has an HDPE-based or EVA-based composition. IE10 demonstrates that the desired properties can also be achieved in the polymer composition using an acid copolymer rather than an ionomer.

Claims

1. A polymer composition comprising: an ethylene-based polymer; one or more of an ionomer and an acid copolymer; a flame retardant filler; a maleic anhydride-functionalized polyolefin, and having a MAH product of 3 or more.

2. The polymer composition according to claim 1, comprising 4% to 16% by weight of the maleic anhydride-functionalized polyolefin based on the total weight of the polymer composition.

3. The polymer composition according to claim 1 or 2, wherein the maleic anhydride-functionalized polyolefin contains 0.4% by weight or more of maleic anhydride based on the total weight of the maleic anhydride-functionalized polyolefin.

4. The polymer composition according to claim 1 or 2, wherein the maleic anhydride-functionalized polyolefin has a density of 0.90 g / cc to 0.920 g / cc as measured according to ASTM D792.

5. The polymer composition according to claim 1 or 2, wherein the ethylene-based polymer has a bimodal molecular weight distribution, a melt flow ratio of 70.0 or more, and a density of 0.945 g / cc or more as measured according to ASTM D792.

6. The polymer composition according to claim 1 or 2, comprising 18% to 50% by weight of the ethylene-based polymer based on the total weight of the polymer composition.

7. The polymer composition according to claim 1 or 2, comprising 0.1% to 10% by weight of the ionomer or acid copolymer based on the total weight of the polymer composition.

8. The polymer composition according to claim 7, comprising 10% to 80% by weight of the flame retardant filler based on the total weight of the polymer composition.

9. The polymer composition according to claim 8, comprising the ionomer, wherein the ionomer is neutralized with one or more metal ions selected from the group consisting of Na, Zn, Li, K, Mg, and combinations thereof.

10. A cable comprising: a conductor; a buffer tube disposed around the conductor and comprising the polymer composition according to claim 1 or 2. A cable comprising the above.