A nano-modified polyethylene optical cable sheath material and its preparation method

Abstract

This invention relates to the field of optical cable material preparation technology, and discloses a nano-modified polyethylene optical cable sheath material and its preparation method. The nano-modified polyethylene optical cable sheath material comprises the following raw materials in parts by weight: 80-100 parts of high-density polyethylene, 25-40 parts of EVA resin, 10-15 parts of modified nylon fiber, 5-8 parts of composite flame retardant, 0.1-1 parts of antioxidant, 0.1-2 parts of coupling agent, and 0.5-5 parts of lubricant. The modified nylon fiber is modified molybdenum disulfide reinforced polyamide 6 fiber. The modified molybdenum disulfide is molybdenum disulfide surface modified with dopamine and then grafted with nano-silica. The composite flame retardant is a core-shell flame retardant with magnesium aluminum hydroxide as the core, maleic anhydride grafted with styrene-ethylene-butadiene-styrene block copolymer as the shell, and P-N flame retardant distributed in the core and shell. This invention, by adding modified nylon fiber and composite flame retardant, endows the polyethylene optical cable sheath material with good mechanical properties and flame retardant properties.

Description

Technical Field

[0001] This invention belongs to the field of optical cable material preparation technology, specifically relating to a nano-modified polyethylene optical cable sheath material and its preparation method. Background Technology

[0002] In recent years, the communications industry has developed rapidly, and the demand for optical cables has gradually increased. However, communication optical cables are usually in a humid environment, which can easily cause oxidation and corrosion of the metal tape protective layer and distortion of the optical fiber signal. In order to improve the reliability of the optical fiber signal and its service life, the upper and lower surfaces of the metal tape are usually heated and bonded with hot melt adhesive to form a metal-plastic composite tape for armoring and shielding, and then protected with an outer protective layer (sheath material).

[0003] The sheath material, serving as the outer protective layer of optical cables, significantly impacts the service life of both the cable and the metal-plastic shielding layer. The performance requirements for the protective layer vary depending on the installation location. For optical fibers laid underground or in ducts, the sheath must possess excellent mechanical properties and be easy to install to ensure normal fiber signal transmission. However, for optical fibers and overhead cables installed indoors in high-rise buildings, not only good mechanical properties but also fire resistance and flame retardancy are necessary. Therefore, optical cable manufacturers and users should thoroughly understand the functional and manufacturing differences of various sheath materials.

[0004] Polyethylene (PE) and polyvinyl chloride (PVC) are the most widely used in flame-retardant optical cable sheathing materials. PVC is inexpensive and easy to process, and is often used in fireproof insulation and flame-retardant sheathing materials for overhead optical cables. However, PVC sheathing materials release toxic gases and dense smoke when exposed to natural fires, endangering health and safety. Polyethylene (PE) has seen rapid development in the insulation and sheathing materials of communication optical fiber cables due to its good chemical stability, non-toxicity, low dielectric loss, and high dielectric strength. However, PE is flammable, and in the event of a fire, optical fiber cables installed indoors can cause secondary fires, threatening people's lives and property. Furthermore, its incompatibility with inorganic fillers limits its application. Therefore, improving the compatibility of inorganic flame retardants with organic matrices and enhancing the strength of cable materials are necessary prerequisites for developing high-performance PE-based cable sheathing materials. Summary of the Invention

[0005] To address the shortcomings mentioned in the background art, the present invention aims to provide a nano-modified polyethylene optical cable sheath material and its preparation method, which, by adding modified nylon fibers and composite flame retardants, endows the material with good mechanical and flame retardant properties.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A nano-modified polyethylene optical cable sheath material comprises the following raw materials in parts by weight: 80-100 parts high-density polyethylene, 25-40 parts EVA resin, 10-15 parts modified nylon fiber, 5-8 parts composite flame retardant, 0.1-1 part antioxidant, 0.1-2 parts coupling agent, and 0.5-5 parts lubricant.

[0008] The modified nylon fiber is a modified molybdenum disulfide reinforced polyamide 6 fiber, wherein the modified molybdenum disulfide is molybdenum disulfide surface modified with dopamine and then grafted with nano-silica.

[0009] The composite flame retardant is a core-shell flame retardant with magnesium aluminum hydroxide as the core, maleic anhydride-grafted styrene-ethylene-butadiene-styrene block copolymer as the shell, and PN flame retardant distributed within the core and shell.

[0010] More preferably, the method for preparing the modified nylon fiber includes the following steps:

[0011] (1) Dissolve tris(hydroxymethyl)aminomethane in deionized water, add 0.1 mol / L hydrochloric acid to adjust the pH to 8-9, then add dopamine hydrochloride to the above solution and stir to mix evenly, then add molybdenum disulfide powder, stir and mix, then sonicate for 2-4 h, and react at 60℃ for 24 h, centrifuge, wash, filter and dry the product to obtain polydopamine modified molybdenum disulfide;

[0012] (2) Add nano silica powder to a mixture of anhydrous ethanol and deionized water in a volume ratio of 10:1, stir evenly and then ultrasonically disperse for 1-2 hours to obtain nano silica dispersion. Then add 3-aminopropyltrimethoxysilane to the dispersion, stir and heat to 80°C for 3-5 hours, centrifuge, wash, filter and dry to obtain silane-modified nano silica.

[0013] (3) Add polydopamine-modified molybdenum disulfide to N,N-dimethylformamide and sonicate for 20-40 min to form a uniform suspension. Then add the silane-modified nano silica obtained in step S2 to the above suspension and sonicate again for 20-40 min. Then heat to 100-110℃ and stir for 4-6 h. After centrifugation, washing, filtration and drying, the modified molybdenum disulfide is obtained.

[0014] (4) Blend with polyamide 6 chips in proportion and prepare modified nylon fiber in one step on a high-speed spinning machine. The melting and spinning temperature is 260~280℃, the draw ratio is 1.25, and the winding speed is 4500m / min.

[0015] More preferably, in step (1), the mass ratio of dopamine hydrochloride to molybdenum disulfide is 1:10~15.

[0016] More preferably, in step (2), the mass ratio of nano-silica powder to 3-aminopropyltrimethoxysilane is 12~15:1.

[0017] More preferably, in step (3), the mass ratio of polydopamine-modified molybdenum disulfide to silane-modified nano-silica is 3~5:1.

[0018] More preferably, the preparation method of the composite flame retardant includes the following steps:

[0019] A. Dissolve magnesium nitrate powder and aluminum nitrate powder in deionized water, add 1.5 mol / L sodium hydroxide solution and stir rapidly until a white precipitate is formed. Then react at room temperature for 1 hour. Then add toluene to the solution and sonicate for 1 hour. Then add concentrated hydrochloric acid and 3-aminopropyltriethoxysilane, sonicate for 1 hour and transfer to a water bath. React at 90°C for 24 hours. Cool to room temperature, wash three times with ethanol by sonication, filter, and dry at 60°C for 16-20 hours to obtain magnesium-aluminum layered double hydroxide.

[0020] B. Dissolve PEG in anhydrous ethanol at a mass ratio of 1:5 to obtain a PEG ethanol solution. Then mix the magnesium-aluminum layered double hydroxide powder and the PEG ethanol solution for 20-30 minutes, filter, wash and dry to obtain PEG-treated magnesium-aluminum layered double hydroxide.

[0021] C. The maleic anhydride-grafted styrene-ethylene-butadiene-styrene block copolymer is melted in a two-roll mill, and PEG-treated magnesium aluminum layered double hydroxide, ammonium polyphosphate, pentaerythritol, and melamine are added. The mixture is melt-mixed at 185~195℃ for 5~10 min to obtain the core-shell flame retardant.

[0022] More preferably, the molar ratio of magnesium nitrate to aluminum nitrate in step A is 2:1.

[0023] More preferably, in step B, the solid-liquid ratio of the magnesium-aluminum layered double hydroxide powder and the PEG ethanol solution is 1:5~8.

[0024] More preferably, in step C, the mass ratio of maleic anhydride-grafted styrene-ethylene-butadiene-styrene block copolymer, PEG-treated magnesium aluminum layered double hydroxide, ammonium polyphosphate, pentaerythritol and melamine is 4:1:0.5:0.2:0.2.

[0025] A method for preparing a nano-modified polyethylene optical cable sheath material includes the following steps:

[0026] S1. Add high-density polyethylene, EVA resin, antioxidant, coupling agent and lubricant to a high-speed mixing pot and mix thoroughly for 10-20 minutes. Then melt, plasticize and blend the mixture through a twin-screw extruder, and extrude and granulate to obtain polymer particles.

[0027] S2. Polymer particles, modified nylon fibers, and composite flame retardants are added to a high-speed mixing pot for premixing. The mixture is then melted and blended in a twin-screw extruder, extruded and granulated, and dried to obtain nano-modified polyethylene optical cable sheath material.

[0028] The beneficial effects of this invention are:

[0029] This invention modifies the surface of molybdenum disulfide with dopamine and then grafts nano-silica onto it. The modified molybdenum disulfide is then used to reinforce polyamide 6, resulting in modified nylon fibers. This improves the strength and abrasion resistance of the nylon fibers. Adding this to polyethylene materials significantly enhances the tensile strength and impact resistance of the material. The composite flame retardant of this invention uses maleic anhydride-grafted styrene-ethylene-butadiene-styrene block copolymer to coat magnesium aluminum double hydroxide, forming a core-shell structure. This improves the dispersion of the inorganic flame retardant in the polymer matrix. Simultaneously, the PN flame retardant is blended into the shell of the maleic anhydride-grafted styrene-ethylene-butadiene-styrene block copolymer, enabling synergistic flame retardancy with the inorganic flame retardant and mutually promoting each other, thus imparting excellent flame retardant properties to the material. Detailed Implementation

[0030] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0031] It should be noted that all raw materials used in this sub-example are commercially available reagents. Among them, the antioxidant is one or more of antioxidant 300, antioxidant 168, and antioxidant 1010; the coupling agent is one or more of silane coupling agent KH550, silane coupling agent KH560, silane coupling agent Si-69, titanate coupling agent NDZ-201, and titanate coupling agent JTW-311; and the lubricant is one or more of stearate, paraffin wax, and polyethylene wax. Example

[0032] A method for preparing modified nylon fibers includes the following steps:

[0033] (1) Dissolve 6.0g of tris(hydroxymethyl)aminomethane in 50ml of deionized water, add 0.1mol / L hydrochloric acid to adjust the pH to 8-9, then add 2.5g of dopamine hydrochloride to the above solution and stir to mix evenly, then add 30.5g of molybdenum disulfide powder, stir and mix, then sonicate for 3h, and react at 60℃ for 24h. Centrifuge, wash, filter and dry the product to obtain polydopamine modified molybdenum disulfide;

[0034] (2) 7.5g of nano silica powder was added to a mixture of 50ml of anhydrous ethanol and deionized water in a volume ratio of 10:1. After stirring evenly, the mixture was ultrasonically dispersed for 1.5h to obtain a nano silica dispersion. Then, 0.5g of 3-aminopropyltrimethoxysilane was added to the dispersion, stirred and heated to 80℃ for 4h, centrifuged, washed, filtered and dried to obtain silane-modified nano silica.

[0035] (3) Add 4.0g of polydopamine-modified molybdenum disulfide to 50ml of N,N-dimethylformamide and sonicate for 20-40min to form a uniform suspension. Then add 1.2g of silane-modified nano silica obtained in step S2 to the above suspension and sonicate again for 30min. Then heat to 105℃ and stir for 5h. After centrifugation, washing, filtration and drying, the modified molybdenum disulfide is obtained.

[0036] (4) Blend with polyamide 6 chips in proportion and prepare modified nylon fiber in one step on a high-speed spinning machine. The melting and spinning temperature is 260~280℃, the draw ratio is 1.25, and the winding speed is 4500m / min. Example

[0037] A method for preparing a composite flame retardant includes the following steps:

[0038] A. Dissolve 10.5g magnesium nitrate powder and 5.3g aluminum nitrate powder in 80ml deionized water, add 50ml 1.5mol / L sodium hydroxide solution and stir rapidly until a white precipitate is formed. Then react at room temperature for 1h. Then add toluene to the solution and sonicate for 1h. Then add 5ml concentrated hydrochloric acid and 2.5g 3-aminopropyltriethoxysilane, sonicate for 1h and then transfer to a water bath. React at 90℃ for 24h. Cool to room temperature, wash three times with ethanol by sonication, filter, and dry at 60℃ for 18h to obtain magnesium-aluminum layered double hydroxide.

[0039] B. Dissolve PEG in anhydrous ethanol at a mass ratio of 1:5 to obtain a PEG ethanol solution. Then mix 4.5g of magnesium aluminum layered double hydroxide powder with 30ml of PEG ethanol solution for 20-30min, filter, wash and dry to obtain PEG-treated magnesium aluminum layered double hydroxide.

[0040] C. 40g of maleic anhydride-grafted styrene-ethylene-butadiene-styrene block copolymer was melted in a two-roll mill, and 10g of PEG-treated magnesium aluminum layered double hydroxide, 5g of ammonium polyphosphate, 2g of pentaerythritol, and 2g of melamine were added. The mixture was melted and mixed at 190°C for 8 minutes to obtain the core-shell flame retardant. Example

[0041] A nano-modified polyethylene optical cable sheath material comprises the following raw materials in parts by weight: 80 parts high-density polyethylene, 40 parts EVA resin, 10 parts modified nylon fiber, 8 parts composite flame retardant, 0.1 parts antioxidant 1010, 0.05 parts silane coupling agent KH550, 0.05 parts titanate coupling agent NDZ-201, and 5 parts stearate.

[0042] The modified nylon fiber is the modified molybdenum disulfide reinforced polyamide 6 fiber prepared in Example 1; the composite flame retardant is the core-shell flame retardant prepared in Example 2, which has magnesium aluminum double hydroxide as the core, maleic anhydride-grafted styrene-ethylene-butadiene-styrene block copolymer as the shell, and PN flame retardant distributed in the core and shell.

[0043] The preparation method of the above-mentioned nano-modified polyethylene optical cable sheath material includes the following steps:

[0044] S1. High-density polyethylene, EVA resin, antioxidant 1010, silane coupling agent KH550, titanate coupling agent NDZ-201, and stearate are added to a high-speed mixing pot and mixed thoroughly for 15 minutes. Then, the mixture is melted, plasticized, and blended through a twin-screw extruder, and extruded and granulated to obtain polymer particles.

[0045] S2. Polymer particles, modified nylon fibers, and composite flame retardants are added to a high-speed mixing pot for premixing. The mixture is then melted and blended in a twin-screw extruder, extruded and granulated, and dried to obtain nano-modified polyethylene optical cable sheath material. Example

[0046] A nano-modified polyethylene optical cable sheath material comprises the following raw materials in parts by weight: 100 parts high-density polyethylene, 25 parts EVA resin, 15 parts modified nylon fiber, 5 parts composite flame retardant, 1 part antioxidant 300, 1 part silane coupling agent KH560, 1 part titanate coupling agent JTW-311, and 0.5 parts paraffin wax;

[0047] The modified nylon fiber is the modified molybdenum disulfide reinforced polyamide 6 fiber prepared in Example 1; the composite flame retardant is the core-shell flame retardant prepared in Example 2, which has magnesium aluminum double hydroxide as the core, maleic anhydride-grafted styrene-ethylene-butadiene-styrene block copolymer as the shell, and PN flame retardant distributed in the core and shell.

[0048] The preparation method of the above-mentioned nano-modified polyethylene optical cable sheath material includes the following steps:

[0049] S1. High-density polyethylene, EVA resin, antioxidant 300, silane coupling agent KH560, titanate coupling agent JTW-311, and paraffin are added to a high-temperature mixing pot and mixed thoroughly for 10 minutes. Then, the mixture is melted, plasticized, and blended through a twin-screw extruder, and extruded and granulated to obtain polymer particles.

[0050] S2. Polymer particles, modified nylon fibers, and composite flame retardants are added to a high-speed mixing pot for premixing. The mixture is then melted and blended in a twin-screw extruder, extruded and granulated, and dried to obtain nano-modified polyethylene optical cable sheath material. Example

[0051] A nano-modified polyethylene optical cable sheath material comprises the following raw materials in parts by weight: 90 parts high-density polyethylene, 32 parts EVA resin, 13 parts modified nylon fiber, 6 parts composite flame retardant, 0.5 parts antioxidant 168, 0.5 parts silane coupling agent KH550, 0.5 parts silane coupling agent Si-69, and 3 parts polyethylene wax.

[0052] The modified nylon fiber is the modified molybdenum disulfide reinforced polyamide 6 fiber prepared in Example 1; the composite flame retardant is the core-shell flame retardant prepared in Example 2, which has magnesium aluminum double hydroxide as the core, maleic anhydride-grafted styrene-ethylene-butadiene-styrene block copolymer as the shell, and PN flame retardant distributed in the core and shell.

[0053] The preparation method of the above-mentioned nano-modified polyethylene optical cable sheath material includes the following steps:

[0054] S1. High-density polyethylene, EVA resin, antioxidant 168, silane coupling agent KH550, silane coupling agent Si-69 parts, and polyethylene wax are added to a high-temperature mixing pot and mixed thoroughly for min. Then, the mixture is melted, plasticized, and blended through a twin-screw extruder, and extruded and granulated to obtain polymer particles.

[0055] S2. Polymer particles, modified nylon fibers, and composite flame retardants are added to a high-speed mixing pot for premixing. The mixture is then melted and blended in a twin-screw extruder, extruded and granulated, and dried to obtain nano-modified polyethylene optical cable sheath material.

[0056] Comparative Example 1

[0057] A nano-modified polyethylene optical cable sheath material comprises the following raw materials in parts by weight: 90 parts high-density polyethylene, 32 parts EVA resin, 6 parts composite flame retardant, 0.5 parts antioxidant 168, 0.5 parts silane coupling agent KH550, 0.5 parts silane coupling agent Si-69, and 3 parts polyethylene wax.

[0058] The composite flame retardant is the core-shell flame retardant prepared in Example 2, which has a magnesium aluminum double hydroxide as the core, maleic anhydride-grafted styrene-ethylene-butadiene-styrene block copolymer as the shell, and PN flame retardant distributed within the core and shell.

[0059] The preparation method of the above-mentioned nano-modified polyethylene optical cable sheath material includes the following steps:

[0060] S1. High-density polyethylene, EVA resin, antioxidant 168, silane coupling agent KH550, silane coupling agent Si-69 parts, and polyethylene wax are added to a high-temperature mixing pot and mixed thoroughly for min. Then, the mixture is melted, plasticized, and blended through a twin-screw extruder, and extruded and granulated to obtain polymer particles.

[0061] S2. The polymer particles and composite flame retardant are added to a high-speed mixing pot for premixing. The mixture is then melted and blended in a twin-screw extruder, extruded and granulated, and dried to obtain nano-modified polyethylene optical cable sheath material.

[0062] Comparative Example 2

[0063] A nano-modified polyethylene optical cable sheath material comprises the following raw materials in parts by weight: 90 parts high-density polyethylene, 32 parts EVA resin, 13 parts modified nylon fiber, 0.5 parts antioxidant 168, 0.5 parts silane coupling agent KH550, 0.5 parts silane coupling agent Si-69, and 3 parts polyethylene wax.

[0064] The modified nylon fiber is the modified molybdenum disulfide reinforced polyamide 6 fiber prepared in Example 1.

[0065] The preparation method of the above-mentioned nano-modified polyethylene optical cable sheath material includes the following steps:

[0066] S1. High-density polyethylene, EVA resin, antioxidant 168, silane coupling agent KH550, silane coupling agent Si-69 parts, and polyethylene wax are added to a high-temperature mixing pot and mixed thoroughly for min. Then, the mixture is melted, plasticized, and blended through a twin-screw extruder, and extruded and granulated to obtain polymer particles.

[0067] S2. The polymer particles and modified nylon fibers are added to a high-speed mixing pot for premixing. The mixture is then melted and blended in a twin-screw extruder, extruded and granulated, and dried to obtain nano-modified polyethylene optical cable sheath material.

[0068] Performance testing

[0069] I. Mechanical property testing

[0070] The nano-modified polyethylene optical cable sheath materials from Examples 3-5 and Comparative Examples 1-2 were cut into test specimens, and their mechanical properties were tested using a universal testing machine. Referring to GB / T 528-2009, the molded specimens were cut into dumbbell-shaped tensile strips of 25 mm × 4 mm, with a tensile rate of 20 mm / min. The test results are shown in Table 2.

[0071] Table 1. Test results of mechanical properties of nano-modified polyethylene optical cable sheath material

[0072]

[0073] As can be seen from the data in Table 1, the mechanical properties of the material prepared in Comparative Example 1 are worse than those of other groups. In this invention, after modifying the surface of molybdenum disulfide with dopamine and grafting nano-silica, the polyamide 6 is reinforced by modified molybdenum disulfide to obtain modified nylon fiber, which improves the strength and wear resistance of nylon fiber. When added to polyethylene material, it can significantly improve the tensile strength and impact strength of the material.

[0074] II. Flame retardant performance test

[0075] The nano-modified polyethylene optical cable sheath materials from Examples 3-5 and Comparative Examples 1-2 were made into standard specimens of 127×12.7×3.2mm. Horizontal and vertical (UL-94) combustion tests were conducted according to ASTM D3801-1996 standard, and oxygen index (LOI) tests were conducted according to ASTM D2863-70 standard. The data are shown in Table 2 below.

[0076] Table 2. Test results of flame retardant properties of nano-modified polyethylene optical cable sheath material.

[0077]

[0078] As can be seen from the data in Table 2, the flame retardant performance of the cable sheath material prepared in Comparative Example 2 is worse than that of other groups. No composite flame retardant was added in Comparative Example 3. The composite flame retardant of this invention uses maleic anhydride-grafted styrene-ethylene-butadiene-styrene block copolymer to coat magnesium aluminum double hydroxide to form a core-shell structure, which improves the dispersion effect of inorganic flame retardant in polymer matrix. At the same time, PN flame retardant is incorporated into the shell of maleic anhydride-grafted styrene-ethylene-butadiene-styrene block copolymer through blending, which can synergistically promote flame retardancy with inorganic flame retardant and give the material good flame retardant performance.

[0079] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A nanomodified polyethylene cable jacket material characterized by, The raw materials include the following components by weight: high-density polyethylene 80~100 parts, EVA resin 25~40 parts, modified nylon fiber 10~15 parts, composite flame retardant 5~8 parts, antioxidant 0.1~1 part, coupling agent 0.1~2 parts, lubricant 0.5~5 parts; The modified nylon fiber is modified molybdenum disulfide reinforced polyamide 6 fiber, and the modified molybdenum disulfide is molybdenum disulfide surface modified by dopamine and then grafted with nano-silicon dioxide; The composite flame retardant is a core-shell flame retardant with magnesium-aluminum double hydroxide as the core, maleic anhydride grafted styrene-ethylene-butadiene-styrene block copolymer as the shell, and P-N flame retardant distributed in the core-shell. The preparation method of the modified nylon fiber comprises the following steps: (1) Dissolve tris(hydroxymethyl)aminomethane in deionized water, add 0.1 mol / L hydrochloric acid to adjust the pH to 8~9, then add dopamine hydrochloride to the above solution and stir to mix uniformly, then add molybdenum disulfide powder, stir and mix, then ultrasonic treatment for 2~4h, and reaction at 60℃ for 24h, centrifugal washing, filtration and drying to obtain polydopamine modified molybdenum disulfide; (2) Add nano-silicon dioxide powder to a mixture of anhydrous ethanol and deionized water in a volume ratio of 10:1, stir uniformly, then ultrasonic dispersion for 1~2h to obtain a nano-silicon dioxide dispersion, then add 3-aminopropyltrimethoxysilane to the dispersion, stir and heat to 80℃ for reaction for 3~5h, centrifugal washing, filtration and drying to obtain silane modified nano-silicon dioxide; (3) Add polydopamine modified molybdenum disulfide to N,N-dimethylformamide and ultrasonic treatment for 20~40min to form a uniform suspension, then add the silane modified nano-silicon dioxide obtained in step S2 to the suspension, ultrasonic treatment for 20~40min again, then heat to 100~110℃, stir and react for 4~6h, centrifugal washing, filtration and drying of the product to obtain the modified molybdenum disulfide; (4) Blend with polyamide 6 chips in proportion, and prepare the modified nylon fiber by one-step method on a high-speed spinning machine, with a melting and spinning temperature of 260~280℃, a draw ratio of 1.25, and a winding speed of 4500m / min.

2. The nanomodified polyethylene cable jacket material of claim 1, wherein, The mass ratio of dopamine hydrochloride to molybdenum disulfide in step (1) is 1:10~15.

3. The nanomodified polyethylene cable jacket material of claim 1, wherein, The mass ratio of nano-silicon dioxide powder to 3-aminopropyltrimethoxysilane in step (2) is 12~15:

1.

4. The nanomodified polyethylene cable jacket material of claim 1, wherein, The mass ratio of polydopamine modified molybdenum disulfide to silane modified nano-silicon dioxide in step (3) is 3~5:

1.

5. The nanomodified polyethylene cable jacket material of claim 1, wherein, The preparation method of the composite flame retardant comprises the following steps: A. Dissolve magnesium nitrate powder and aluminum nitrate powder in deionized water, add 1.5 mol / L sodium hydroxide solution and stir quickly until white precipitate is generated, then react at room temperature for 1h, then add toluene and ultrasonic for 1h, then add concentrated hydrochloric acid and 3-aminopropyltriethoxysilane, ultrasonic stirring for 1h, then transfer to a water bath, react at 90℃ for 24h, cool to room temperature, ultrasonic washing with ethanol for three times, suction filtration, and drying at 60℃ for 16~20h to obtain magnesium-aluminum layered double hydroxide; B. dissolving PEG in anhydrous ethanol according to a mass ratio of 1:5 to obtain a PEG ethanol solution, then mixing the magnesium-aluminum layered double hydroxide powder and the PEG ethanol solution for 20-30 min, filtering, washing, drying to obtain the PEG-treated magnesium-aluminum layered double hydroxide; C. melting the maleic anhydride grafted styrene-ethylene-butadiene-styrene block copolymer in an open mill, adding the PEG-treated magnesium-aluminum layered double hydroxide, ammonium polyphosphate, pentaerythritol, melamine, and melting and mixing at 185-195℃ for 5-10 min to obtain the core-shell flame retardant.

6. The nanomodified polyethylene cable jacket material of claim 5, wherein, The molar ratio of magnesium nitrate to aluminum nitrate in step A is 2:

1.

7. The nanomodified polyethylene cable jacket material of claim 5, wherein, The solid-liquid ratio of the magnesium-aluminum layered double hydroxide powder to the PEG ethanol solution in step B is 1:5-8.

8. The nanomodified polyethylene cable jacket material of claim 5, wherein, The mass ratio of the maleic anhydride grafted styrene-ethylene-butadiene-styrene block copolymer, the PEG-treated magnesium-aluminum layered double hydroxide, ammonium polyphosphate, pentaerythritol, and melamine in step C is 4:1:0.5:0.2:0.

2.

9. A method of preparing a nanoreinforced polyethylene cable jacket material according to any one of claims 1 to 8, characterized in that, The method comprises the following steps: S1. adding high-density polyethylene, EVA resin, antioxidant, coupling agent, and lubricant into a high-mixing pot and mixing thoroughly for 10-20 min, then melting, plasticizing, and blending the mixture through a double-screw extruder to obtain polymer particles by extruding and granulating; S2. adding the polymer particles and modified nylon fiber and composite flame retardant into a high-mixing pot for premixing, then melting and blending the mixture through a double-screw extruder to extrude and granulate, and drying to obtain the nano-modified polyethylene optical cable sheath material.

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