Low-smoke halogen-free flame-retardant cable and preparation method thereof

Abstract

This application relates to the technical field of cables, specifically disclosing a low-smoke halogen-free flame-retardant cable and its preparation method. A low-smoke halogen-free flame-retardant cable includes an outer sheath, a braided layer, and several cable cores. The outer sheath comprises the following raw materials in parts by weight: 25-50 parts of ethylene-butyl acrylate copolymer; 20-40 parts of ethylene propylene diene monomer (EPDM) rubber; 10-30 parts of hydrogenated petroleum resin; 20-40 parts of polyethylene resin; 50-60 parts of aluminum hydroxide; 20-30 parts of magnesium hydroxide; 10-20 parts of synergistic flame retardant; 1-2 parts of paraffin wax; 1-3 parts of imidacloprid; and 2-5 parts of additives. The cable of this application can be used in locations such as nuclear power plants and subway stations, and has advantages such as high flame retardancy, low smoke, and high mechanical strength.

Description

Technical Field

[0001] This application relates to the technical field of cables, and more specifically, to a low-smoke halogen-free flame-retardant cable and a method for its preparation. Background Technology

[0002] Low-smoke halogen-free cables are environmentally friendly cables made from adhesives free of halogens (F, Cl, Br, I, At) and environmentally unfriendly substances such as lead, cadmium, chromium, and mercury. They do not emit toxic fumes when burning. These cables possess superior flame-retardant properties, produce very little smoke during combustion, and release no corrosive gases. They are widely used in nuclear power plants, subway stations, telephone exchanges and computer control centers, high-rise buildings, hotels, radio and television stations, important military facilities, oil platforms, and other locations with high population density and low air density.

[0003] Currently, the main approach to improve the flame retardant effect of cable materials is to add inorganic flame retardant materials. However, adding only inorganic flame retardant materials does not produce good flame retardant effects, and a large amount of inorganic flame retardant materials are unevenly dispersed, which affects the strength and other properties of the cable. Therefore, improvements are needed. Summary of the Invention

[0004] To improve the flame retardant effect and strength of cables, this application provides a low-smoke halogen-free flame-retardant cable and its preparation method, adopting the following technical solution:

[0005] In a first aspect, this application provides a low-smoke halogen-free flame-retardant cable, comprising an outer sheath, a braided layer, and a plurality of cable cores, wherein the outer sheath comprises the following raw materials in parts by weight:

[0006] 25-50 parts of ethylene-butyl acrylate copolymer;

[0007] 20-40 parts of EPDM rubber;

[0008] 10-30 parts of hydrogenated petroleum resin;

[0009] 20-40 parts of polyethylene resin;

[0010] 50-60 parts aluminum hydroxide;

[0011] 20-30 parts magnesium hydroxide;

[0012] Synergistic flame retardant 10-20 parts;

[0013] 1-2 parts paraffin;

[0014] 1-3 parts of insecticide;

[0015] Additives 2-5 parts.

[0016] By adopting the above technical solutions, this application preferably uses ethylene-butyl acrylate copolymer, ethylene propylene diene monomer (EPDM) rubber, hydrogenated petroleum resin, and polyethylene resin to enable the cable material to contain both flexible and rigid materials. The polyethylene resin acts as a skeleton structure in the cable, effectively enhancing the mechanical strength of the cable sheath. Simultaneously, it enables the sheath to achieve better resistance to ultraviolet radiation, corrosion, and high-temperature aging. This application preferably uses aluminum hydroxide, magnesium hydroxide, and synergistic flame retardants for flame retardancy. Aluminum hydroxide and magnesium hydroxide can absorb heat and isolate air. During thermal decomposition, they can release bound water and collect a large amount of latent heat to reduce the surface temperature of the material in the flame. Furthermore, the water vapor released during combustion can also hinder combustion and wet the smoke. After combustion, a ceramicized isolation layer can be formed on the material surface, which can stably improve the flame retardant effect of the cable sheath and reduce smoke.

[0017] This application incorporates terbufotalin into the outer sheath. Terbufotalin, in conjunction with paraffin wax, lubricates and encapsulates aluminum hydroxide, magnesium hydroxide, and synergistic flame retardants, improving the dispersion of flame retardant materials within the outer sheath and resulting in a uniform, low-smoke flame-retardant effect. Terbufotalin is rich in fatty acids, which can undergo a weak plasticizing and cross-linking reaction with EPDM rubber. Furthermore, over time, terbufotalin migrates to the surface; its distinctive odor repels organisms, reducing biological damage to the outer sheath and extending the cable's service life.

[0018] Optionally, the synergistic flame retardant includes an iron-based metal-organic framework.

[0019] By adopting the above technical solutions, metal-organic frameworks (MOFs), as an emerging nano-flame retardant material, have significant advantages in the field of polymer flame retardancy due to their high specific surface area, porous structure, and tunable chemical properties. This is achieved by integrating metal catalysts to promote char layer formation. Iron and its compounds both have catalytic char formation effects and excellent smoke suppression effects, thus improving the smoke suppression effect of the outer sheath. Furthermore, iron-based metal-organic frameworks can combine with aluminum hydroxide and magnesium hydroxide to form a char layer during combustion, consisting of aluminum oxide and magnesium oxide encapsulated and reinforced by the iron-based metal-organic framework. This effectively inhibits the escape of heat and smoke generated during combustion, and the generated water vapor remains inside the cable, reducing the content of combustible gases inside the cable, thereby further improving the flame retardant effect of the cable.

[0020] Optionally, the synergistic flame retardant includes an iron-based metal-organic framework and piperazine pyrophosphate.

[0021] By adopting the above technical solution, piperazine pyrophosphate, as a novel halogen-free phosphorus-based flame retardant, possesses both a gas-phase / condensed-phase dual flame-retardant mechanism and high thermal stability, which can significantly improve the fire resistance of polymers. The iron-based metal-organic framework, after combustion, can form nano-metal oxides that synergistically catalyze the formation of a dense and stable char layer with the phosphate derived from piperazine pyrophosphate, thus further enhancing the flame-retardant effect of cables.

[0022] Optionally, the synergistic flame retardant includes an iron-based metal-organic framework-piperazine pyrophosphate synergistic flame retardant.

[0023] By adopting the above technical solution, loading piperazine pyrophosphate onto the iron-based metal-organic framework can effectively improve the compatibility between piperazine pyrophosphate and the cable substrate, and improve the dispersion effect of piperazine pyrophosphate in the cable substrate. At the same time, a tightly connected structure is formed between the two, which promotes a strong synergistic effect between the iron-based metal-organic framework and piperazine pyrophosphate, thereby further promoting the formation of char in the condensed phase, inhibiting heat release and reducing smoke generation, thus synergistically optimizing the flame retardant and smoke suppression performance of the cable.

[0024] Optionally, the iron-based metal framework-piperazine pyrophosphate synergistic flame retardant is prepared as follows: ferric chloride, 2-aminoterephthalic acid, and N,N-dimethylformamide are mixed, fumaric acid is added, the mixture is reacted, the solid is retained by centrifugation, washed, and dried to obtain an aminated iron-based metal-organic framework; the aminated iron-based metal-organic framework is mixed with acetonitrile, and piperazine pyrophosphate, 1-ethyl-3-(3-dimethylpropylamine)carbodiimide hydrochloride, 4-dimethylaminopyridine, N,N-diisopropylethylamine, and 1-hydroxybenzotriazole are added sequentially, the mixture is reacted continuously, cooled, centrifuged, the solid is retained, washed, and dried to obtain the synergistic flame retardant.

[0025] By adopting the above technical solution, 2-aminoterephthalic acid is used to modify the iron-based metal-organic framework to obtain amino groups. The iron-based metal-organic framework contains both amino and carboxyl groups, which are then connected by chemical bonds to form an effective bond between the aminated iron-based metal framework and piperazine pyrophosphate, thus forming a stable synergistic flame retardant.

[0026] Optionally, the insecticide is black soldier fly larvae ester.

[0027] By adopting the above technical solutions, black soldier flies have a wide range of food sources, low feed costs, relatively simple breeding techniques, low operating costs, and stable composition.

[0028] Optionally, the outer sheath may further include 5-10 parts of filler, the filler comprising halloysite nanotubes and silica.

[0029] By adopting the above technical solution, halloysite nanotubes have a hollow, one-dimensional, multi-layered tubular structure with characteristics such as small diameter, high aspect ratio, and high elastic modulus. They also possess advantages such as high thermal stability, flame retardancy, and easy dispersibility. Using halloysite nanotubes in combination with silica as fillers, a filler network can be constructed within the outer sheath, thereby stabilizing and improving the mechanical strength of the outer sheath. Furthermore, due to the hollow structure of the halloysite nanotubes, they can effectively trap small molecule degradation products within their cavities and insulate against heat, thus hindering combustion and further enhancing the flame retardant effect of the outer sheath.

[0030] Optionally, the silica is supported on the halloysite nanotubes.

[0031] By adopting the above technical solution, loading silica onto halloysite nanotubes can reduce the agglomeration between silica particles and between silica and halloysite nanotubes, thus promoting uniform dispersion of the filler.

[0032] Optionally, the filler is a filler modified with a modifier, including tebufenozide, silane coupling agent, and stearic acid.

[0033] By adopting the above technical solution, the filler is modified by combining terbufotalin, silane coupling agent and stearic acid, which can further improve the dispersion effect of the filler in the cable. Furthermore, due to the presence of terbufotalin, the compatibility between the filler and EPDM rubber can be further improved, thereby enhancing the bonding performance between the filler network and the cable layer and further improving the mechanical strength of the cable.

[0034] Secondly, this application provides a method for preparing a low-smoke halogen-free flame-retardant cable, which adopts the following technical solution:

[0035] A method for preparing a low-smoke halogen-free flame-retardant cable includes the following steps:

[0036] S1. Multiple cable cores are twisted together and pressed against each other;

[0037] S2. Fill the outer circumferential surface of the twisted cable cores with filler material;

[0038] S3. A braided layer is provided on the outer periphery of the filler, and the cable core, filler and braided layer are in close contact.

[0039] S4. An outer sheath layer is extruded outside the braided layer to produce a low-smoke halogen-free flame-retardant cable.

[0040] In summary, this application has the following beneficial effects:

[0041] 1. In this application, aluminum hydroxide and magnesium hydroxide are preferably used together for flame retardancy. Aluminum hydroxide and magnesium hydroxide can absorb heat and isolate air. When heated and decomposed, they can release bound water and collect a large amount of latent heat to reduce the surface temperature of the material in the flame. In addition, the water vapor released during combustion can also hinder combustion and wet the smoke. After combustion, a ceramic isolation layer can be formed on the surface of the material, which can stably improve the flame retardant effect of the cable outer sheath and reduce smoke.

[0042] This application utilizes terbufotalin in combination with paraffin wax to lubricate and encapsulate aluminum hydroxide, magnesium hydroxide, and synergistic flame retardants, improving the dispersion of flame retardant materials within the outer sheath and resulting in a uniform, low-smoke flame-retardant effect. Terbufotalin can migrate to the surface, and its distinctive odor repels organisms, reducing their damage to the outer sheath and extending the cable's service life.

[0043] 2. The iron-based metal-organic framework in this application can work with aluminum hydroxide and magnesium hydroxide to form a carbon layer during combustion, which is wrapped by aluminum oxide and magnesium oxide and reinforced by the iron-based metal-organic framework. This effectively inhibits the heat and smoke generated during combustion from escaping, and the water vapor generated will remain inside the cable, reducing the content of combustible gases inside the cable, thereby further improving the flame retardant effect of the cable.

[0044] 3. This application loads piperazine pyrophosphate onto an iron-based metal-organic framework, which can effectively improve the compatibility between piperazine pyrophosphate and the cable substrate, and improve the dispersion effect of piperazine pyrophosphate in the cable substrate. At the same time, a tightly connected structure is formed between the two, which promotes a strong synergistic effect between the iron-based metal-organic framework and piperazine pyrophosphate, thereby further promoting the formation of char in the condensed phase, inhibiting heat release and reducing smoke generation, thus synergistically optimizing the flame retardant and smoke suppression performance of the cable. Detailed Implementation

[0045] The present application will be further described in detail below with reference to the embodiments.

[0046] Preparation Example

[0047] Example of preparation of iron-based metal framework-piperazine pyrophosphate synergistic flame retardant

[0048] Preparation Example 1

[0049] The preparation is as follows: Ferric chloride, 2-aminoterephthalic acid, and N,N-dimethylformamide are mixed, fumaric acid is added, the mixture is reacted, the solid is retained by centrifugation, washed, and dried to obtain an aminated iron-based metal-organic framework; the aminated iron-based metal-organic framework is mixed with acetonitrile, and piperazine pyrophosphate, 1-ethyl-3-(3-dimethylpropylamine)carbodiimide hydrochloride, 4-dimethylaminopyridine, N,N-diisopropylethylamine, and 1-hydroxybenzotriazole are added sequentially, the mixture is reacted continuously, cooled, centrifuged, the solid is retained, washed, and dried to obtain a synergistic flame retardant.

[0050] Packing preparation example

[0051] Preparation Example 2

[0052] 5 kg of silica and 5 kg of halloysite nanotubes were mixed to obtain filler 1.

[0053] Preparation Example 3

[0054] Ethanol and deionized water were mixed in a volume ratio of 5:1 to form a solution. Then, 4.0 g of silane coupling agent APTES was added and the mixture was stirred and hydrolyzed for 1 h. Then, 1.0 g of halloysite nanotubes was added and the mixture was sonicated for half an hour. Finally, the mixture was refluxed and stirred at 80 °C for 24 h, filtered, washed with ethanol, dried at 60 °C, and ground into powder to obtain modified halloysite nanotubes.

[0055] 1.0 g of halloysite nanotubes were fully dispersed in 44 mL of deionized water and sonicated for 2 h. Then, 17.6 g of anhydrous citric acid was added and sonicated for another 4 h to protonate the halloysite nanotubes. At the same time, 200 mL of water glass and 600 mL of deionized water were mixed evenly by mechanical stirring. The mixture was then heated to 80 °C. After the temperature stabilized, 6.25 mL of ethanol was added dropwise, followed by the slowly added protonated halloysite nanotube dispersion. The pH of the reaction system was adjusted to 6.0 with pre-prepared 2.5 M sulfuric acid. Finally, 400 mL of ethanol was added and the mixture was stirred for 1 h. The reaction was then stopped and allowed to stand overnight. The mixture was centrifuged, washed three times with water and three times with alcohol, dried in a forced-air environment at 60 °C, and sieved through a 100-mesh sieve to obtain the silica-supported halloysite nanotube composite filler 2.

[0056] Example of modified filler preparation

[0057] Preparation Example 4

[0058] Mix 1g of tebufenozide, 1g of silane coupling agent, and 1g of stearic acid to obtain a modifier. Mix the modifier with filler 1 at a mass ratio of 1:100, stir, and modify at 90℃ for 20 minutes to obtain modified filler 1.

[0059] Preparation Example 5

[0060] Take 1g of tebufenozide, 1g of silane coupling agent, and 1g of stearic acid and mix them to obtain a modifier. Mix the modifier with filler 2 at a mass ratio of 1:100, stir, and modify at 90℃ for 20 minutes to obtain modified filler 2.

[0061] Example

[0062] Examples 1-3

[0063] On the one hand, this application provides a low-smoke halogen-free flame-retardant cable, including an outer sheath, a braided layer and several cable cores. The outer sheath includes the following raw materials: ethylene butyl acrylate copolymer, EPDM rubber, hydrogenated petroleum resin, polyethylene resin, aluminum hydroxide, magnesium hydroxide, synergistic flame retardant, paraffin wax, insecticide, and additives.

[0064] The synergistic flame retardant is a metal-organic framework, and the additives include an equal mass of antioxidant (antioxidant 1010), crosslinking agent (triallyl isocyanate), and ultraviolet absorber (titanium dioxide).

[0065] The ethylene-butyl acrylate copolymer has a butyl acrylate monomer molar content of 17%; the EPDM rubber is Exxon 7100N type; the polyethylene resin is Dow HDPE; the hydrogenated petroleum resin is hydrogenated C9 petroleum resin with a softening point of 95-135℃; and the focused piperazine phosphate has a particle size D50≤6.2μm.

[0066] The preparation method of the outer sheath is as follows: EPDM rubber, hydrogenated petroleum resin, antioxidant 1010, titanium dioxide, paraffin wax, insecticide, and triallyl isocyanurate are mixed evenly and then extruded using a twin-screw extruder at temperatures of 125℃, 135℃, 150℃, 160℃, 170℃, 175℃, 175℃, 165℃, and 160℃. After granulation, an intermediate product is obtained. The intermediate product is then combined with ethylene-butyl acrylate copolymer and poly(ethylene-butyl acrylate)... Ethylene resin, aluminum hydroxide, magnesium hydroxide, and synergistic flame retardant are blended and then internally mixed at 165°C for 10 minutes. The mixture is then melt-plasticized and extruded using a two-stage twin-screw-single-screw extruder. The twin-screw temperatures are set to 110°C, 120°C, 130°C, 140°C, 145°C, and 140°C, while the single-screw temperatures are set to 100°C, 110°C, 120°C, 130°C, 120°C, and 120°C. Granulation is then performed to obtain the outer sheath material.

[0067] On the other hand, this application provides a method for preparing a low-smoke halogen-free flame-retardant cable, comprising the following steps: S1, twisting multiple cable cores together in contact with each other;

[0068] S2. Fill the outer circumferential surface of the twisted cable cores with filler material;

[0069] S3. A braided layer is provided on the outer periphery of the filler, and the cable core, filler and braided layer are in close contact.

[0070] S4. An outer sheath layer is extruded outside the braided layer to produce a low-smoke halogen-free flame-retardant cable.

[0071] Table 1 Composition of Examples 1-3

[0072]

[0073] Example 4

[0074] The difference from Example 2 is that the synergistic flame retardant includes an equal mass of iron-based metal framework and piperazine pyrophosphate.

[0075] Example 5

[0076] The difference from Example 2 is that the synergistic flame retardant includes the iron-based metal framework-piperazine pyrophosphate synergistic flame retardant prepared in Preparation Example 1.

[0077] Example 6

[0078] The difference from Example 2 is that the outer sheath also includes 8 kg of filler 1 prepared in Example 2.

[0079] Example 7

[0080] The difference from Example 2 is that the outer sheath also includes 8 kg of filler 2 prepared in Preparation Example 3.

[0081] Example 8

[0082] The difference from Example 2 is that the outer sheath also includes 8 kg of the modified filler 1 prepared in Preparation Example 4.

[0083] Example 9

[0084] The difference from Example 2 is that the outer sheath also includes 8 kg of the modified filler 2 prepared in Preparation Example 5.

[0085] Comparative Example

[0086] Comparative Example 1

[0087] The difference between this comparative example and Example 2 is that no insecticide was added in this comparative example.

[0088] Comparative Example 2

[0089] The difference between this comparative example and Example 3 is that no synergistic flame retardant was added in this comparative example.

[0090] Performance testing

[0091] (1) The outer sheath was tested according to the test method recorded in GB T 32129-2015 "Halogen-free Low-smoke Flame-retardant Cable Material for Wires and Cables". The test indicators were oxygen index, smoke density under flame conditions and tensile strength.

[0092] Table 2 Performance Testing

[0093]

[0094] By comparing the performance test results in Table 2, we can find that:

[0095] 1. A comparison of Examples 1-3 and Comparative Examples 1-2 reveals that the limiting oxygen index, smoke density, and tensile strength of the outer sheaths prepared in Examples 1-3 are reduced. This indicates that the use of insecticides in this application can lubricate and encapsulate aluminum hydroxide, magnesium hydroxide, and synergistic flame retardants in conjunction with paraffin wax, improving the dispersion effect of flame retardant materials in the outer sheath and resulting in a uniform, low-smoke flame-retardant effect. Insecticides are rich in fatty acids, which can undergo a weak plasticizing and cross-linking reaction with EPDM rubber. Furthermore, over time, insecticides can migrate to the surface, and their distinctive odor can repel organisms, reducing biological damage to the outer sheath and extending the cable's service life.

[0096] Iron-based metal-organic frameworks can work with aluminum hydroxide and magnesium hydroxide to form a carbon layer during combustion, which is wrapped by aluminum oxide and magnesium oxide and reinforced by iron-based metal-organic frameworks. This effectively inhibits the heat and smoke generated during combustion from escaping, and the water vapor generated will remain inside the cable, reducing the content of combustible gases inside the cable, thereby further improving the flame retardant effect of the cable.

[0097] 2. A comparison between Examples 4-5 and Example 2 reveals that the cables prepared in Examples 4-5 exhibit improved impact resistance and tensile strength. This indicates that the iron-based metal-organic framework in this application, after combustion, can form nano-metal oxides that synergistically catalyze the formation of a dense and stable carbon layer with piperazine pyrophosphate-derived phosphates, thus further enhancing the flame-retardant effect of the cable. Loading piperazine pyrophosphate onto the iron-based metal-organic framework effectively improves the compatibility between piperazine pyrophosphate and the cable substrate, enhancing the dispersion effect of piperazine pyrophosphate in the cable substrate. Simultaneously, a tightly connected structure is formed between the two, further promoting a strong synergistic effect between the iron-based metal-organic framework and piperazine pyrophosphate, thereby further promoting condensed phase carbonization.

[0098] 3. A comparison between Examples 6-7 and Example 2 reveals that the impact resistance and tensile strength of the cables prepared in Examples 6-7 are improved. This indicates that the use of halloysite nanotubes and silica as fillers in this application can construct a filler network in the outer sheath, thereby stabilizing and improving the mechanical strength of the outer sheath. At the same time, due to the hollow structure of halloysite nanotubes, they can capture a large number of small molecule degradation products and block heat, thus hindering combustion and further improving the flame retardant effect of the outer sheath.

[0099] 4. A comparison between Examples 8-9 and Example 2 reveals that the impact resistance and tensile strength of the cables prepared in Examples 8-9 are improved. This indicates that the modification of the filler using terbufotalin, silane coupling agent, and stearic acid in this application can further improve the dispersion effect of the filler in the cable. Furthermore, the presence of terbufotalin can further improve the compatibility between the filler and EPDM rubber, thereby improving the bonding performance between the filler network and the cable layer, and thus further improving the mechanical strength of the cable.

[0100] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A low-smoke, halogen-free, flame-retardant cable, characterized in that, It includes an outer sheath, a braided layer, and several cable cores, wherein the outer sheath comprises the following raw materials in parts by weight: 25-50 parts of ethylene-butyl acrylate copolymer; 20-40 parts of EPDM rubber; 10-30 parts of hydrogenated petroleum resin; 20-40 parts of polyethylene resin; 50-60 parts aluminum hydroxide; 20-30 parts magnesium hydroxide; Synergistic flame retardant 10-20 parts; 1-2 parts paraffin; 1-3 parts of insecticide; Additives 2-5 parts.

2. The low-smoke halogen-free flame-retardant cable according to claim 1, characterized in that: The synergistic flame retardant includes an iron-based metal-organic framework.

3. The low-smoke halogen-free flame-retardant cable according to claim 2, characterized in that: The synergistic flame retardant comprises an iron-based metal framework and piperazine pyrophosphate.

4. The low-smoke halogen-free flame-retardant cable according to claim 3, characterized in that: The synergistic flame retardant includes an iron-based metal-organic framework-piperazine pyrophosphate synergistic flame retardant.

5. A low-smoke halogen-free flame-retardant cable according to claim 4, characterized in that: The iron-based metal framework-piperazine pyrophosphate synergistic flame retardant is prepared as follows: ferric chloride, 2-aminoterephthalic acid, and N,N-dimethylformamide are mixed, fumaric acid is added, the mixture is reacted, the solid is retained by centrifugation, washed, and dried to obtain an aminated iron-based metal-organic framework; the aminated iron-based metal-organic framework is mixed with acetonitrile, and piperazine pyrophosphate, 1-ethyl-3-(3-dimethylpropylamine)carbodiimide hydrochloride, 4-dimethylaminopyridine, N,N-diisopropylethylamine, and 1-hydroxybenzotriazole are added sequentially, the mixture is reacted continuously, cooled, centrifuged, the solid is retained, washed, and dried to obtain the synergistic flame retardant.

6. The low-smoke halogen-free flame-retardant cable according to claim 1, characterized in that: The insecticide is black soldier fly larvae ester.

7. The low-smoke halogen-free flame-retardant cable according to claim 1, characterized in that: The outer sheath also includes 5-10 parts of filler, which includes halloysite nanotubes and silica.

8. A low-smoke halogen-free flame-retardant cable according to claim 7, characterized in that: The silica is supported on the halloysite nanotubes.

9. A low-smoke halogen-free flame-retardant cable according to claim 8, characterized in that: The filler is a filler that has been modified by a modifier, which includes tebufenozide, silane coupling agent and stearic acid.

10. A method for preparing a low-smoke halogen-free flame-retardant cable according to any one of claims 1-9, characterized in that, Includes the following steps: S1. Multiple cable cores are twisted together and pressed against each other; S2. Fill the outer circumferential surface of the twisted cable cores with filler material; S3. A braided layer is provided on the outer periphery of the filler, and the cable core, filler and braided layer are in close contact. S4. An outer sheath layer is extruded outside the braided layer to produce a low-smoke halogen-free flame-retardant cable.

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