Thermoplastic low-temperature-resistant high-flame-retardant low-smoke halogen-free cable material as well as preparation method and application thereof

Abstract

The invention provides a thermoplastic low-temperature-resistant high-flame-retardant low-smoke halogen-free cable material as well as a preparation method and application thereof, and the thermoplastic low-temperature-resistant high-flame-retardant low-smoke halogen-free cable material comprises the following components in parts by weight: 25-45 parts of linear low-density polyethylene; 25 to 45 parts of an ethylene-butyl acrylate copolymer; 15-25 parts of a polyolefin elastomer; 8-15 parts of a compatilizer; 4-8 parts of carbon black master batch; 160 to 260 parts of a flame retardant; 1-2 parts of an antioxidant; and 2-5 parts of a lubricant. The cable material provided by the invention comprises the linear low-density polyethylene, the ethylene-butyl acrylate copolymer, the polyolefin elastomer, the compatilizer, the flame retardant and other inorganic fillers, all the components are cooperated, and especially the ethylene-butyl acrylate copolymer is introduced, so that the cable material has relatively good low-temperature resistance, and the cable material can be widely applied to the field of cable materials. Excellent impact resistance and flexibility can be kept at-50 DEG C; in addition, the cable material provided by the invention also has relatively good flame retardant property.

Description

Technical Field

[0001] This invention belongs to the field of cable material technology, and relates to a thermoplastic, low-temperature resistant, high flame-retardant, low-smoke, halogen-free cable material, its preparation method, and its application. Background Technology

[0002] With increasing demands for fire safety and environmental protection, low-smoke halogen-free cable materials are widely used in important facilities such as nuclear power plants, subway stations, high-rise buildings, and hospitals due to their unique advantages of low smoke, low toxicity, and halogen-free environmental friendliness. In recent years, various industries have continuously increased their requirements for the multi-functionality of cable performance, and cable material companies have placed greater emphasis on the development of high-performance special materials, such as ultra-high flame retardancy, high temperature resistance, low temperature resistance, and chemical corrosion resistance. However, few companies have developed high flame retardant and low-temperature resistant cable materials. It is well known that high flame retardant, low-smoke halogen-free cable materials contain a large amount of inorganic flame retardant, which significantly reduces their low-temperature performance; the higher the amount of inorganic flame retardant added, the worse the low-temperature performance. The national standard GB / T 32129-2015 "Halogen-free Low-smoke Flame-retardant Cable Material for Wires and Cables" only requires that the performance of low-smoke halogen-free flame-retardant thermoplastic polyolefin sheathing material meet the requirement that the number of sample failures be ≤15 / 30 at -25℃. However, it does not specify the requirements for the low-temperature tensile strength of the sheathing material. Moreover, the market currently requires thermoplastic low-temperature resistant and high flame-retardant cable material to further meet the higher requirement of -50℃, but there are few products that meet the requirements.

[0003] Given the limited development of thermoplastic low-temperature resistant and flame-retardant cable materials in the industry, the purpose of this invention is to prepare a high flame-retardant cable material that can withstand temperatures as low as -50°C, for use in harsh environments such as subways, power transmission in cold regions, and underground substations, ensuring that the cable can transmit power normally in an environment of -50°C while reducing the risk of fire. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a thermoplastic, low-temperature resistant, high flame-retardant, low-smoke, halogen-free cable material, its preparation method, and its application.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] In a first aspect, the present invention provides a thermoplastic low-temperature resistant, high flame-retardant, low-smoke, halogen-free cable material, wherein the thermoplastic low-temperature resistant, high flame-retardant, low-smoke, halogen-free cable material comprises the following components by weight:

[0007]

[0008] The cable material provided by this invention includes linear low-density polyethylene, ethylene-butyl acrylate copolymer, polyolefin elastomer, compatibilizer, and inorganic fillers such as flame retardant. The components work synergistically, especially the introduction of ethylene-butyl acrylate copolymer, which gives the cable material good low-temperature resistance. It can maintain excellent impact resistance and flexibility at -50℃. In addition, the cable material provided by this invention also has good flame retardant properties.

[0009] The thermoplastic low-temperature resistant, high flame retardant, low-smoke halogen-free cable material of the present invention, wherein low-temperature resistant means that the cable material can pass the low-temperature tensile test and the low-temperature impact embrittlement test at -50℃, high flame retardant means that the finished cable can pass the bundled burning test, and low smoke means that the smoke density of the finished cable is above 60%.

[0010] In this invention, the amount of linear low-density polyethylene used in the thermoplastic low-temperature resistant, high flame-retardant, low-smoke, halogen-free cable material can be 25 parts, 26 parts, 28 parts, 30 parts, 32 parts, 34 parts, 35 parts, 36 parts, 38 parts, 40 parts, 42 parts, 44 parts, 45 parts, etc., by weight.

[0011] In this invention, the amount of ethylene-butyl acrylate copolymer in the thermoplastic low-temperature resistant, high flame-retardant, low-smoke, halogen-free cable material can be 25 parts, 26 parts, 28 parts, 30 parts, 32 parts, 34 parts, 35 parts, 36 parts, 38 parts, 40 parts, 42 parts, 44 parts, 45 parts, etc., by weight.

[0012] In this invention, the amount of polyolefin elastomer in the thermoplastic low-temperature resistant, high flame-retardant, low-smoke, halogen-free cable material can be 15 parts, 16 parts, 18 parts, 20 parts, 22 parts, 24 parts, 25 parts, etc., by weight.

[0013] In this invention, the amount of compatibilizer used in the thermoplastic low-temperature resistant, high flame-retardant, low-smoke halogen-free cable material can be 8 parts, 9 parts, 10 parts, 12 parts, 14 parts, 15 parts, etc., by weight.

[0014] In this invention, the amount of carbon black masterbatch used in the thermoplastic low-temperature resistant, high flame-retardant, low-smoke halogen-free cable material can be 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, etc., by weight.

[0015] In this invention, the amount of flame retardant in the thermoplastic low-temperature resistant, high flame retardant, low-smoke halogen-free cable material can be 160 parts, 170 parts, 180 parts, 190 parts, 200 parts, 210 parts, 220 parts, 230 parts, 240 parts, 250 parts, 260 parts, etc., by weight.

[0016] In this invention, the amount of antioxidant used in the thermoplastic low-temperature resistant, high flame-retardant, low-smoke halogen-free cable material can be 1 part, 1.5 parts, 2 parts, etc., by weight.

[0017] In this invention, the amount of lubricant used in the thermoplastic low-temperature resistant, high flame-retardant, low-smoke, halogen-free cable material can be 2 parts, 3 parts, 4 parts, 5 parts, etc., by weight.

[0018] Preferably, the linear low-density polyethylene has a bimodal molecular weight distribution. Typically, the embrittlement temperature of linear low-density polyethylene is lower than that of low-density polyethylene and high-density polyethylene, allowing it to withstand even lower temperatures. The bimodal molecular weight distribution of linear low-density polyethylene can suppress the rigidification of molecular chains at low temperatures, maintaining flexibility and thus preserving the material's mechanical properties.

[0019] Preferably, the melt flow rate index of the linear low-density polyethylene at 190°C and 2.16 kg is 0.2 to 0.5 g / 10 min, such as 0.2 g / 10 min, 0.3 g / 10 min, 0.4 g / 10 min, 0.5 g / 10 min, etc.

[0020] Preferably, the melt flow rate index of the ethylene-butyl acrylate copolymer at 190°C and 2.16 kg is 1 to 5 g / 10 min, such as 1 g / 10 min, 1.5 g / 10 min, 2 g / 10 min, 2.5 g / 10 min, 3 g / 10 min, 3.5 g / 10 min, 4 g / 10 min, 4.5 g / 10 min, 5 g / 10 min, etc.

[0021] Preferably, the melting temperature of the ethylene-butyl acrylate copolymer is 90-100°C, such as 90°C, 92°C, 94°C, 95°C, 96°C, 98°C, 100°C, etc.

[0022] Ethylene-butyl acrylate copolymer exhibits excellent low-temperature performance, maintaining good toughness and flexibility at low temperatures and resisting embrittlement, hardening, and cracking. It can maintain material performance over a wide low-temperature range. Furthermore, ethylene-butyl acrylate copolymer has high polarity; at the same monomer acid content, its polarity is approximately twice that of ethylene-vinyl acetate copolymer. This higher polarity results in stronger interaction between the ethylene-butyl acrylate copolymer and the inorganic filler.

[0023] Preferably, the polyolefin elastomer is a metallocene-catalyzed polyolefin elastomer (i.e., a polyolefin elastomer synthesized using a metallocene catalyst). Metallocene-catalyzed polyolefin elastomers have a narrower molecular weight distribution, which is more conducive to synergistic motion in low-temperature environments, thereby improving the low-temperature performance of the material.

[0024] Preferably, the molecular weight distribution index of the polyolefin elastomer is between 1.2 and 2, such as 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, etc.

[0025] Preferably, the compatibilizer includes PE-g-MAH and / or POE-g-MAH.

[0026] Preferably, the compatibilizer comprises a mixture of PE-g-MAH and POE-g-MAH in a mass ratio of 1:(0.8–1.2) (e.g., 1:0.8, 1:0.9, 1:1, 1:1.1, 1:1.2, etc.). This type of compatibilizer contains both polar and non-polar groups, and can act as an interfacial bonding agent between the matrix resin and the additive, playing a bridging role and improving the mechanical properties and low-temperature tensile properties of the cable material to a certain extent.

[0027] Preferably, the carbon black masterbatch uses polyethylene as a carrier and has a carbon black content of 40% to 50%, such as 40%, 42%, 44%, 45%, 46%, 48%, 50%, etc.

[0028] Preferably, the flame retardant comprises aluminum hydroxide with a surface modified by a coupling agent and / or magnesium hydroxide with a surface modified by a coupling agent.

[0029] Preferably, the coupling agent comprises vinylsilane.

[0030] Using the coupling agent vinylsilane to modify the surface of aluminum hydroxide and magnesium hydroxide can improve the compatibility between the flame retardant and the base material, reduce agglomeration, and thus further improve the flame retardant performance of the cable material.

[0031] Preferably, the aluminum hydroxide with the surface modified by the coupling agent has a coupling agent content of 1% to 2% based on 100% of the mass of unmodified aluminum hydroxide, such as 1%, 1.2%, 1.4%, 1.5%, 1.6%, 1.8%, 2%, etc.

[0032] Preferably, the magnesium hydroxide with surface modified by coupling agent has a coupling agent content of 1% to 2% based on 100% of the mass of unmodified magnesium hydroxide, such as 1%, 1.2%, 1.4%, 1.5%, 1.6%, 1.8%, 2%, etc.

[0033] Preferably, the particle size of the aluminum hydroxide and magnesium hydroxide with the surface modified by the coupling agent is independently 1 to 10 micrometers, for example, 1 micrometer, 2 micrometer, 3 micrometer, 4 micrometer, 5 micrometer, 6 micrometer, 7 micrometer, 8 micrometer, 9 micrometer, 10 micrometer, etc.

[0034] Preferably, the flame retardant comprises 60-110 parts (e.g., 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, etc.) of aluminum hydroxide with surface modified by a coupling agent and 100-150 parts (e.g., 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, etc.) of magnesium hydroxide with surface modified by a coupling agent.

[0035] This invention does not specifically limit the preparation methods of the surface-modified aluminum hydroxide and surface-modified magnesium hydroxide, which can be produced by chemical synthesis. Taking surface-modified aluminum hydroxide as an example, it can be prepared by the following method:

[0036] Aluminum hydroxide and a coupling agent are mixed and stirred under heating conditions to obtain aluminum hydroxide with a surface modified by the coupling agent.

[0037] Preferably, the heating is to a temperature of 90-110°C, such as 90°C, 95°C, 100°C, 105°C, 110°C, etc.

[0038] Preferably, the stirring time is 30 to 40 minutes, for example, 30 minutes, 35 minutes, 40 minutes, etc.

[0039] Magnesium hydroxide with surface-modified coupling agent can also be prepared using the above method, and will not be described in detail here.

[0040] Preferably, the antioxidant includes any one or a combination of at least two of amine antioxidants, phosphite antioxidants, and thioester antioxidants, and more preferably a mixture of amine antioxidants, phosphite antioxidants, and thioester antioxidants.

[0041] Preferably, the lubricant comprises silicone masterbatch.

[0042] In a second aspect, the present invention provides a method for preparing the thermoplastic low-temperature resistant, high flame-retardant, low-smoke, halogen-free cable material as described in the first aspect, the method comprising the following steps:

[0043] First, linear low-density polyethylene, ethylene-butyl acrylate copolymer, polyolefin elastomer, and compatibilizer are prepared into powders with a D50 particle size of 40-100 micrometers (e.g., 40 micrometers, 45 micrometers, 50 micrometers, 55 micrometers, 60 micrometers, 65 micrometers, 70 micrometers, 75 micrometers, 80 micrometers, 85 micrometers, 90 micrometers, 95 micrometers, 100 micrometers, etc.). Then, the powder is mixed with carbon black masterbatch, flame retardant, antioxidant, and lubricant. After uniform mixing, the mixture is extruded and granulated to obtain the thermoplastic low-temperature resistant, high flame-retardant, low-smoke, halogen-free cable material.

[0044] Preferably, the step of preparing linear low-density polyethylene, ethylene-butyl acrylate copolymer, polyolefin elastomer and compatibilizer into powder with a D50 particle size of 40-100 micrometers specifically includes: preparing linear low-density polyethylene, ethylene-butyl acrylate copolymer, polyolefin elastomer and compatibilizer into powder with a D50 particle size of 40-100 micrometers by passing them through an air jet mill.

[0045] Preferably, the mixing is carried out in a high-speed mixer.

[0046] Preferably, the extrusion granulation is carried out in a twin-screw extruder.

[0047] Preferably, the feed temperature of the twin-screw extruder is controlled between 130 and 160°C (e.g., 130°C, 135°C, 140°C, 145°C, 150°C, 155°C, 160°C, etc.).

[0048] In the preparation method provided by the present invention, linear low-density polyethylene, ethylene-butyl acrylate copolymer, polyolefin elastomer and compatibilizer are first prepared into powder with a D50 particle size of 40-100 micrometers by air jet mill. This allows the powder additives to be more uniformly dispersed in the above powdered raw materials, thereby improving the flame retardant performance and low-temperature performance of the cable material.

[0049] Thirdly, the present invention provides an application of the thermoplastic low-temperature resistant, high flame-retardant, low-smoke halogen-free cable material as described in the first aspect in subways, power transmission in cold regions, and underground substations.

[0050] Compared with the prior art, the present invention has at least the following beneficial effects:

[0051] Compared to commercially available thermoplastic, low-temperature resistant, and highly flame-retardant cable materials using ethylene-vinyl acetate copolymer as the matrix resin, this invention introduces ethylene-butyl acrylate copolymer as the matrix resin. Its molecular chain contains longer, flexible segments, which lower the glass transition temperature, allowing the cable material to maintain excellent impact resistance and flexibility even at -50°C. Furthermore, the processing technology employed in this invention involves first preparing linear low-density polyethylene, ethylene-butyl acrylate copolymer, polyolefin elastomer, and compatibilizer into powder with a D50 particle size of 40–100 micrometers using an air-jet mill. Then, the powder is uniformly mixed with inorganic fillers, and finally, the mixture is extruded using a twin-screw extruder. This process facilitates the uniform dispersion of inorganic fillers in the powdered raw materials, thereby optimizing the flame-retardant and low-temperature performance of the material. Detailed Implementation

[0052] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0053] Preparation Example 1

[0054] This preparation example provides aluminum hydroxide with a surface modified by a coupling agent. The preparation method includes the following steps:

[0055] Aluminum hydroxide (particle size of 5 micrometers) and coupling agent (vinylsilane) were added to a high-speed mixer and stirred at 100°C for 30 min to obtain aluminum hydroxide with surface modified by coupling agent.

[0056] The coupling agent content is 1%, based on the mass of unmodified aluminum hydroxide as 100%.

[0057] Preparation Example 2

[0058] This preparation example provides magnesium hydroxide with a surface modified by a coupling agent. The preparation method includes the following steps:

[0059] Magnesium hydroxide (particle size of 5 micrometers) and coupling agent (vinylsilane) were added to a high-speed mixer and stirred at 100°C for 30 min to obtain magnesium hydroxide with surface modified by coupling agent.

[0060] The coupling agent content is 1%, calculated based on 100% of the mass of unmodified magnesium hydroxide.

[0061] Unless otherwise specified, the information on some raw materials used in the following embodiments and comparative examples of the present invention is shown in Table 1 below:

[0062] Table 1

[0063]

[0064]

[0065] Example 1

[0066] This embodiment provides a thermoplastic low-temperature resistant, high flame-retardant, low-smoke, halogen-free cable material, which, by weight, comprises the following components:

[0067] 45 parts linear low-density polyethylene, 25 parts ethylene-butyl acrylate copolymer, 15 parts metallocene-catalyzed polyolefin elastomer, 10 parts compatibilizer, 5 parts carbon black masterbatch, 90 parts aluminum hydroxide with surface-modified coupling agent, 120 parts magnesium hydroxide with surface-modified coupling agent, 0.5 parts antioxidant 1010, 0.5 parts antioxidant 168, 1 part antioxidant DLTP, and 4 parts silicone masterbatch AL-60.

[0068] The preparation method includes the following steps:

[0069] First, linear low-density polyethylene, ethylene-butyl acrylate copolymer, metallocene-catalyzed polyolefin elastomer, and compatibilizer are prepared into powder with a D50 particle size of 40-100 micrometers using an air jet mill. Then, the above powder is mixed with carbon black masterbatch, aluminum hydroxide with surface-modified coupling agent, magnesium hydroxide with surface-modified coupling agent, antioxidant 1010, antioxidant 168, antioxidant DLTP, and silicone masterbatch in a high-speed mixer. After uniform mixing, the mixture is extruded and granulated through a twin-screw extruder, wherein the material temperature of the twin-screw extruder is controlled at 160°C, to obtain the thermoplastic low-temperature resistant, high flame-retardant, low-smoke halogen-free cable material.

[0070] Example 2

[0071] This embodiment provides a thermoplastic low-temperature resistant, high flame-retardant, low-smoke, halogen-free cable material, which, by weight, comprises the following components:

[0072] 35 parts linear low-density polyethylene, 35 parts ethylene-butyl acrylate copolymer, 15 parts metallocene-catalyzed polyolefin elastomer, 10 parts compatibilizer, 5 parts carbon black masterbatch, 90 parts aluminum hydroxide with surface-modified coupling agent, 120 parts magnesium hydroxide with surface-modified coupling agent, 0.5 parts antioxidant 1010, 0.5 parts antioxidant 168, 1 part antioxidant DLTP, and 4 parts silicone masterbatch AL-60.

[0073] The preparation method is the same as in Example 1.

[0074] Example 3

[0075] This embodiment provides a thermoplastic low-temperature resistant, high flame-retardant, low-smoke, halogen-free cable material, which, by weight, comprises the following components:

[0076] 25 parts linear low-density polyethylene, 45 parts ethylene-butyl acrylate copolymer, 15 parts metallocene-catalyzed polyolefin elastomer, 10 parts compatibilizer, 5 parts carbon black masterbatch, 90 parts aluminum hydroxide with surface-modified coupling agent, 120 parts magnesium hydroxide with surface-modified coupling agent, 0.5 parts antioxidant 1010, 0.5 parts antioxidant 168, 1 part antioxidant DLTP, and 4 parts silicone masterbatch AL-60.

[0077] The preparation method is the same as in Example 1.

[0078] Example 4

[0079] This embodiment provides a thermoplastic low-temperature resistant, high flame-retardant, low-smoke, halogen-free cable material, which, by weight, comprises the following components:

[0080] 25 parts linear low-density polyethylene, 35 parts ethylene-butyl acrylate copolymer, 25 parts metallocene-catalyzed polyolefin elastomer, 15 parts compatibilizer, 5 parts carbon black masterbatch, 110 parts aluminum hydroxide with surface-modified coupling agent, 120 parts magnesium hydroxide with surface-modified coupling agent, 0.5 parts antioxidant 1010, 0.5 parts antioxidant 168, 1 part antioxidant DLTP, and 4 parts silicone masterbatch AL-60.

[0081] The preparation method is the same as in Example 1.

[0082] Example 5

[0083] This embodiment provides a thermoplastic low-temperature resistant, high flame-retardant, low-smoke, halogen-free cable material, which, by weight, comprises the following components:

[0084] 25 parts linear low-density polyethylene, 35 parts ethylene-butyl acrylate copolymer, 25 parts metallocene-catalyzed polyolefin elastomer, 15 parts compatibilizer, 5 parts carbon black masterbatch, 85 parts aluminum hydroxide with surface-modified coupling agent, 125 parts magnesium hydroxide with surface-modified coupling agent, 0.5 parts antioxidant 1010, 0.5 parts antioxidant 168, 1 part antioxidant DLTP, and 4 parts silicone masterbatch AL-60.

[0085] The preparation method is the same as in Example 1.

[0086] Example 6

[0087] The only difference between this embodiment and Embodiment 1 is that linear low-density polyethylene FB2230 is replaced with an equal weight proportion of linear low-density polyethylene 218WJ (which does not have a bimodal molecular weight distribution).

[0088] Example 7

[0089] The only difference between this embodiment and Example 1 is that the metallocene-catalyzed polyolefin elastomer C0570D is replaced with an equal weight proportion of polyolefin elastomer EPDM.

[0090] Comparative Example 1

[0091] This comparative example provides a thermoplastic high flame retardant low smoke halogen-free cable material, which comprises the following components by weight:

[0092] 45 parts linear low-density polyethylene, 25 parts ethylene-vinyl acetate copolymer, 15 parts metallocene-catalyzed polyolefin elastomer, 10 parts compatibilizer, 5 parts carbon black masterbatch, 90 parts aluminum hydroxide with surface-modified coupling agent, 120 parts magnesium hydroxide with surface-modified coupling agent, 0.5 parts antioxidant 1010, 0.5 parts antioxidant 168, 1 part antioxidant DLTP, and 4 parts silicone masterbatch.

[0093] The preparation method includes the following steps:

[0094] First, linear low-density polyethylene, ethylene-vinyl acetate copolymer, metallocene-catalyzed polyolefin elastomer, and compatibilizer are prepared into powder with a D50 particle size of 40-100 micrometers using an air jet mill. Then, the above powder is mixed with carbon black masterbatch, aluminum hydroxide with surface-modified coupling agent, magnesium hydroxide with surface-modified coupling agent, antioxidant 1010, antioxidant 168, antioxidant DLTP, and silicone masterbatch in a high-speed mixer. After uniform mixing, the mixture is extruded and granulated using a twin-screw extruder, wherein the material temperature of the twin-screw extruder is controlled at 160°C, to obtain the thermoplastic high flame retardant low smoke halogen-free cable material.

[0095] Comparative Example 2

[0096] This comparative example provides a thermoplastic high flame retardant low smoke halogen-free cable material, which comprises the following components by weight:

[0097] 45 parts linear low-density polyethylene, 25 parts ethylene-butyl acrylate copolymer, 15 parts metallocene-catalyzed polyolefin elastomer, 10 parts compatibilizer, 5 parts carbon black masterbatch, 90 parts aluminum hydroxide with surface-modified coupling agent, 120 parts magnesium hydroxide with surface-modified coupling agent, 0.5 parts antioxidant 1010, 0.5 parts antioxidant 168, 1 part antioxidant DLTP, and 4 parts silicone masterbatch.

[0098] The preparation method includes the following steps:

[0099] Linear low-density polyethylene, ethylene-butyl acrylate copolymer, metallocene-catalyzed polyolefin elastomer, compatibilizer, carbon black masterbatch, surface-modified aluminum hydroxide, surface-modified magnesium hydroxide, antioxidant 1010, antioxidant 168, antioxidant DLTP, and silicone masterbatch are mixed in a high-speed mixer. After uniform mixing, the mixture is extruded and granulated through a twin-screw extruder. The material temperature of the twin-screw extruder is controlled at 160°C to obtain the thermoplastic high flame retardant low smoke halogen-free cable material.

[0100] The cable materials provided in the embodiments and comparative examples were subjected to performance tests, and the test methods are as follows:

[0101] (1) Tensile strength and elongation at break: in accordance with GB / T 2951.11-2008;

[0102] (2) Elongation at break under low temperature conditions of -50℃: in accordance with GB / T 2951.14-2008;

[0103] (3) Impact embrittlement at -50℃: Performed in accordance with GB / T 2951.14-2008;

[0104] (4) Vertical flame spread test for bundled wires and cables installed vertically: Performed in accordance with GB / T 18380.33;

[0105] (5) Test for smoke density of burning wires and cables: Performed in accordance with GB / T 17651.2.

[0106] The performance test results are shown in Table 2.

[0107] Table 2

[0108]

[0109]

[0110] As can be seen from Table 2, the cable materials provided in Examples 1 to 5 of the present invention all have good low-temperature resistance (elongation at break under -50℃ conditions: 20% to 47%; all can pass the impact embrittlement test under -50℃ conditions), as well as high flame retardancy (charring height in bundled burning test: 0.9 to 1.5 m) and low smoke (smoke density: 88% to 98%).

[0111] Compared with Example 1, the linear low-density polyethylene in Example 6 does not have a bimodal molecular weight distribution, resulting in a decrease in the low-temperature resistance of the cable material. The polyolefin elastomer in Example 7 is not a metallocene-catalyzed polyolefin elastomer, resulting in a decrease in the low-temperature resistance and flame retardancy of the cable material.

[0112] Compared with Example 1, the cable material provided in Comparative Example 1 showed a significant decrease in elongation at break under low temperature conditions of -50°C and failed the impact embrittlement test under low temperature conditions of -50°C; the cable material provided in Comparative Example 2 showed a significant decrease in elongation at break under low temperature conditions of -50°C.

[0113] The applicant declares that this invention illustrates the thermoplastic low-temperature resistant, high flame-retardant, low-smoke halogen-free cable material, its preparation method, and its application through the above embodiments. However, this invention is not limited to the above embodiments, meaning that this invention does not necessarily rely on the above embodiments for implementation. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of raw materials, additions of auxiliary components, and selection of specific methods, etc., all fall within the protection and disclosure scope of this invention.

Claims

1. A thermoplastic, low-temperature resistant, high flame-retardant, low-smoke, halogen-free cable material, characterized in that, The thermoplastic low-temperature resistant, high flame-retardant, low-smoke halogen-free cable material comprises the following components by weight:

2. The thermoplastic low-temperature resistant, high flame-retardant, low-smoke halogen-free cable material according to claim 1, characterized in that, The linear low-density polyethylene has a bimodal molecular weight distribution. Preferably, the linear low-density polyethylene has a melt flow rate index of 0.2 to 0.5 g / 10 min at 190°C and 2.16 kg.

3. The thermoplastic low-temperature resistant, high flame-retardant, low-smoke halogen-free cable material according to claim 1 or 2, characterized in that, The melt flow rate index of the ethylene-butyl acrylate copolymer at 190°C and 2.16 kg is 1-5 g / 10 min. Preferably, the melting temperature of the ethylene-butyl acrylate copolymer is 90–100°C.

4. The thermoplastic low-temperature resistant, high flame-retardant, low-smoke halogen-free cable material according to any one of claims 1-3, characterized in that, The polyolefin elastomer is a metallocene-catalyzed polyolefin elastomer; Preferably, the molecular weight distribution index of the polyolefin elastomer is between 1.2 and 2.

5. The thermoplastic low-temperature resistant, high flame-retardant, low-smoke halogen-free cable material according to any one of claims 1-4, characterized in that, The compatibilizer includes PE-g-MAH and / or POE-g-MAH; Preferably, the compatibilizer comprises a mixture of PE-g-MAH and POE-g-MAH in a mass ratio of 1:(0.8-1.2); Preferably, the carbon black masterbatch uses polyethylene as a carrier and has a carbon black content of 40% to 50%.

6. The thermoplastic low-temperature resistant, high flame-retardant, low-smoke halogen-free cable material according to any one of claims 1-5, characterized in that, The flame retardant includes aluminum hydroxide with a surface modified by a coupling agent and / or magnesium hydroxide with a surface modified by a coupling agent; Preferably, the coupling agent comprises vinylsilane; Preferably, the coupling agent content of the aluminum hydroxide with surface modified by coupling agent is 1% to 2% based on 100% of the mass of unmodified aluminum hydroxide; Preferably, the magnesium hydroxide with the surface modified by the coupling agent has a coupling agent content of 1% to 2% based on 100% of the mass of unmodified magnesium hydroxide; Preferably, the flame retardant comprises 60-110 parts of aluminum hydroxide with a surface modified by a coupling agent and 100-150 parts of magnesium hydroxide with a surface modified by a coupling agent.

7. The thermoplastic low-temperature resistant, high flame-retardant, low-smoke halogen-free cable material according to any one of claims 1-6, characterized in that, The antioxidant includes any one or a combination of at least two of amine antioxidants, phosphite antioxidants, and thioester antioxidants, preferably a mixture of amine antioxidants, phosphite antioxidants, and thioester antioxidants; Preferably, the lubricant comprises silicone masterbatch.

8. A method for preparing a thermoplastic, low-temperature resistant, high flame-retardant, low-smoke, halogen-free cable material as described in any one of claims 1-7, characterized in that, The preparation method includes the following steps: First, linear low-density polyethylene, ethylene-butyl acrylate copolymer, polyolefin elastomer and compatibilizer are prepared into powder with a D50 particle size of 40-100 micrometers. Then, the powder is mixed with carbon black masterbatch, flame retardant, antioxidant and lubricant, and then extruded and granulated to obtain the thermoplastic low-temperature resistant, high flame retardant, low smoke halogen-free cable material.

9. The preparation method according to claim 8, characterized in that, The process of preparing linear low-density polyethylene, ethylene-butyl acrylate copolymer, polyolefin elastomer and compatibilizer into powder with a D50 particle size of 40-100 micrometers specifically includes: preparing linear low-density polyethylene, ethylene-butyl acrylate copolymer, polyolefin elastomer and compatibilizer into powder with a D50 particle size of 40-100 micrometers by passing them through an air jet mill. Preferably, the mixing is carried out in a high-speed mixer; Preferably, the extrusion granulation is carried out in a twin-screw extruder; Preferably, the material temperature of the twin-screw extruder is controlled between 130 and 160°C.

10. The application of a thermoplastic, low-temperature resistant, high flame-retardant, low-smoke, halogen-free cable material as described in any one of claims 1-7 in subways, power transmission in cold regions, and underground substations.

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