Lightweight anti-aging cable sheath material based on expanded microspheres and preparation method of lightweight anti-aging cable sheath material

Abstract

The invention relates to a lightweight aging-resistant cable sheath material based on expanded microspheres and a preparation method thereof. The lightweight aging-resistant cable sheath material comprises the following raw materials in parts by weight: 63-75 parts of ethylene propylene diene monomer, 22-32 parts of chlorinated polyethylene, 13-21 parts of expanded microspheres, 6-8 parts of a processing aid, 5-7 parts of zinc oxide, 2-4 parts of a vulcanizing agent and 0.3-0.5 part of an assistant crosslinker. The ethylene propylene diene monomer is used as a main body, so that the material is endowed with excellent anti-aging performance; wherein the chlorinated polyethylene can enhance the aging resistance of the material; wherein the expansion microspheres can enable the sheath material to be light and improve the aging resistance of the material; the modified boron nitride containing various functional groups is added into the expanded microspheres as one of the raw materials, so that the mechanical property and the aging resistance of the material are remarkably enhanced, and the performance is stable; the light anti-aging plastic has the advantages of being good in anti-aging performance, high in aging resistance, light in weight and capable of reducing the agglomeration phenomenon.

Description

Technical Field

[0001] The present invention belongs to the technical field of cable materials, and particularly relates to a lightweight anti-aging cable sheath material based on expandable microspheres and a preparation method thereof. Background Art

[0002] With the rapid development of modern industry and technology, cables, as important carriers for power transmission and signal transmission, play an indispensable role in various fields. A cable generally consists of a conductor, insulating material, and a cable sheath. Among them, the cable sheath has the greatest impact on the performance of the cable. Traditional cable sheath materials mostly use polymer materials such as polyvinyl chloride (PVC), polyethylene (PE), or cross-linked polyethylene (XLPE). These materials are widely used due to their good insulation, processability, and cost advantages. However, traditional materials are prone to performance degradation during long-term service, and their anti-aging performance is insufficient. Expandable microspheres, as a new type of functional filler, have shown great application potential in the field of lightweight composite materials in recent years. However, the current application research on expandable microspheres in cable sheath materials is still in its initial stage, and there are still some key problems to be solved. First, the commonly used polymer matrices for expandable microspheres include acrylic resin, phenolic resin, styrene and vinylidene chloride copolymer, etc. These polymer matrices generally have poor mechanical properties. Therefore, it is urgent to solve the above problems to meet the higher requirements of the cable material technology field. Therefore, it is very necessary to provide a lightweight anti-aging cable sheath material based on expandable microspheres and a preparation method thereof, which has good anti-aging performance, strong anti-aging property, lightweight, and reduced agglomeration phenomenon. Summary of the Invention

[0003] (I) Technical Problems In view of the above-mentioned current situation of the prior art, the present application mainly addresses the following technical problems: 1. Traditional cable sheath materials are prone to performance degradation during long-term service, and their anti-aging performance is insufficient. 2. Although the new type of functional filler expandable microspheres has great application potential, its application in cable sheath materials is in the initial research stage, and there are some key problems to be solved. 3. The commonly used polymer matrices for expandable microspheres generally have poor mechanical properties and cannot meet the higher requirements of cable materials.

[0004] (II) Technical Solutions The purpose of the present invention is to overcome the deficiencies of the prior art and provide a lightweight anti-aging cable sheath material based on expandable microspheres and a preparation method thereof, which has good anti-aging performance, strong anti-aging property, lightweight, and reduced agglomeration phenomenon.

[0005] The object of the present invention is achieved as follows: A lightweight and aging-resistant cable sheath material based on expandable microspheres and a preparation method thereof, comprising the following raw materials in parts by weight: 63-75 parts of ethylene propylene diene monomer (EPDM), 22-32 parts of chlorinated polyethylene, 13-21 parts of expandable microspheres, 6-8 parts of processing aids, 5-7 parts of zinc oxide, 2-4 parts of vulcanizing agent, 0.3-0.5 part of co-crosslinking agent.

[0006] A preparation method of a lightweight and aging-resistant cable sheath material based on expandable microspheres, comprising the following steps: Add EPDM and chlorinated polyethylene into an open mill, after primary mixing, then add expandable microspheres, processing aids, zinc oxide, vulcanizing agent and co-crosslinking agent, conduct secondary mixing, and after the mixing is completed, vulcanize to obtain a lightweight and aging-resistant cable sheath material based on expandable microspheres.

[0007] Further, the vulcanizing agent is dicumyl peroxide; the co-crosslinking agent is one of triallyl cyanurate and triallyl isocyanurate; the processing aid is one of zinc stearate, white paraffin wax, stearic acid and polyethylene wax.

[0008] Further, the time for both the primary mixing and the secondary mixing is 5-10 min.

[0009] In the present invention, EPDM is used as the main raw material of the material. EPDM has excellent ozone and ultraviolet resistance, endowing the material with excellent aging resistance; chlorinated polyethylene is added to the raw materials, which has good compatibility with EPDM, and their vulcanization properties are similar, which can further enhance the aging resistance of the material; adding zinc oxide to the raw materials can improve the crosslinking density of the finished product and promote vulcanization.

[0010] The raw materials of the expandable microspheres are as follows in parts by weight: 23-31 parts of methyl methacrylate, 19-25 parts of butyl acrylate, 20-28 parts of methacrylic acid, 4-6 parts of emulsifier, 80-100 parts of deionized water, 8-16 parts of modified boron nitride, 0.2-0.4 part of potassium persulfate.

[0011] Further, the expandable microspheres are prepared through the following steps: A1: Add methyl methacrylate, butyl acrylate, methacrylic acid and emulsifier into deionized water, mix and stir evenly, then add modified boron nitride, mechanically stir for 20-30 min and then place in an ice bath tank for ultrasonic treatment for 10-20 min to form an emulsion; A2: Add potassium persulfate (initiator) to the emulsion, and introduce nitrogen as a protective gas. In a water bath at 60-80 °C, mechanically stir and react for 12-24 h to obtain a product. After centrifuging the product, wash and dry to obtain expandable microspheres.

[0012] Further, the emulsifier is one of alkylphenol polyoxyethylene ether and sodium dodecyl sulfate.

[0013] In the present invention, Pickering emulsion polymerization is used to prepare expandable microspheres with a core-shell structure. After heat treatment, the expandable microspheres with this core-shell structure will expand internally to form a hollow microsphere structure. This structure can not only lighten the sheath material but also block oxygen in the external environment, improving the anti-aging performance.

[0014] The modified boron nitride is prepared through the following steps: Step 1: Mix γ-aminopropyltriethoxysilane (silane coupling agent KH-550) with an ethanol aqueous solution (volume ratio of ethanol / water is 4:1), add acetic acid solution (mass fraction 10%) to adjust the pH of the system to 4-5, stir at room temperature for 20 min to fully hydrolyze γ-aminopropyltriethoxysilane; then add boron nitride, and stir and react in a constant temperature water bath at 60 °C for 6 h. After the reaction is completed, centrifuge and separate, wash with anhydrous ethanol multiple times, dry under vacuum, and grind to obtain silane-modified boron nitride; In the present invention, boron nitride is modified with γ-aminopropyltriethoxysilane to introduce amino groups for subsequent reactions, obtaining silane-modified boron nitride.

[0015] Step 2: Add pentaerythritol and toluene into a three-necked flask equipped with a thermometer, electromagnetic stirrer, spherical condenser and tail gas treatment device. Slowly drip phosphorus trichloride into the flask with a constant pressure dropping funnel. After the dripping is completed, heat the device. When the temperature reaches 78 °C, keep the temperature constant and reflux for 3 h. After the reaction is completed, remove the solvent benzene and excess phosphorus trichloride by vacuum distillation to obtain intermediate product 1; In the present invention, pentaerythritol and phosphorus trichloride react. By adjusting the molar ratio of pentaerythritol to phosphorus trichloride to be close to 1:2 (phosphorus trichloride is slightly in excess), intermediate product 1 is obtained; the specific reaction is as Figure 1 shown.

[0016] Step 3: Add intermediate product 1 and acetone into a three-necked flask equipped with a magnetic stirrer, condenser and thermometer. Dissolve 2,4-dihydroxybenzophenone and sodium hydroxide in acetone and distilled water respectively. After stirring and mixing evenly, add them into the flask in sequence. Heat the device. When the temperature reaches 60 °C, keep the temperature constant and reflux for 4 h. After the reaction is completed, filter by suction, and wash the filter residue with distilled water and ethanol multiple times to obtain intermediate product 2; In the present invention, sodium hydroxide can react with the hydroxyl group at the para position in the 2,4-dihydroxybenzophenone molecule to form a phenolate with stronger nucleophilicity. The phenolate can attack the carbon atom connected to the chlorine atom on intermediate 1 to generate an ether bond. By adjusting the molar ratio of 2,4-dihydroxybenzophenone to intermediate 1 to be close to 1:1 (with intermediate 1 being slightly in excess), it can ensure that only one chlorine atom in the intermediate 1 molecule undergoes a substitution reaction, thereby generating intermediate 2. The specific reaction process is as Figure 2 shown.

[0017] Step 4: Mix the silane-modified boron nitride and N,N-dimethylformamide, and ultrasonically treat to make the silane-modified boron nitride evenly dispersed. Then add intermediate 2 and triethylamine. At room temperature, magnetically stir for 4 h, and then in a water bath at 55 °C, ultrasonically treat for 4 h. Then remove the water bath and magnetically stir at room temperature for 6 h. After the reaction is completed, perform suction filtration, take the filter residue, wash it multiple times with absolute ethanol, dry it, grind it to obtain modified boron nitride.

[0018] In the present invention, the chlorine group in the intermediate 2 molecule undergoes a nucleophilic substitution reaction with the amino group on the silane-modified boron nitride, and triethylamine acts as an acid-binding agent to catalyze the reaction to obtain modified boron nitride.

[0019] Furthermore, the dosage ratio of γ-aminopropyltriethoxysilane, ethanol aqueous solution, and boron nitride in step 1 is 9.6 g:50 mL:1 g.

[0020] Furthermore, the dosage ratio of pentaerythritol, toluene, and phosphorus trichloride in step 2 is 13.6 g:100 mL:29.2 g.

[0021] Furthermore, the dosage ratio of intermediate 1, acetone, 2,4-dihydroxybenzophenone, sodium hydroxide, and distilled water in step 3 is 28.3 g:100 mL:21.5 g:3.9 g:20 mL.

[0022] Furthermore, the dosage ratio of silane-modified boron nitride, N,N-dimethylformamide, intermediate 2, and triethylamine in step 4 is 1 g:100 mL:8.6 g:4.2 g.

[0023] In the present invention, boron nitride is formed by alternating boron and nitrogen atoms to form a hexagonal lattice, having excellent thermal stability and mechanical properties. Through co-modification with a silane coupling agent and intermediate 2, the hydrophobicity of boron nitride is greatly improved, promoting its dispersion in the matrix and reducing the agglomeration phenomenon. Therefore, the performance of the modified boron nitride is more easily exerted, enhancing the mechanical properties and heat aging resistance of the matrix. By modifying boron nitride, the migration resistance of the small molecule intermediate 2 is also improved; In addition, the modified boron nitride molecules also contain phosphite, benzophenone and pentaerythritol structures. Among them, phosphite is a type of auxiliary antioxidant that can play an antioxidant role by decomposing peroxides and chelating metal ions, thereby protecting the polymer material from thermal-oxidative aging during processing and use; In addition, benzophenone contains a carbonyl (C=O) functional group. It can not only absorb ultraviolet light with a wavelength range of 280 - 380 nm, but also undergo energy transfer with the excited-state molecules in the polymer material, converting them into stable ground-state molecules, and can play a synergistic role with phosphite, greatly enhancing the anti-aging performance of the matrix; Finally, the molecule contains a pentaerythritol skeleton, and this unique chemical structure can improve the thermal stability of the matrix.

[0024] (III) Beneficial Effects 1. The sheath material prepared by the present invention uses ethylene-propylene-diene monomer rubber as the main raw material, endowing the material with excellent anti-aging performance; 2. Chlorinated polyethylene is added to the raw materials to further enhance the aging resistance of the material; 3. The self-made expandable microspheres are added to the raw materials, which can not only lighten the weight of the sheath material, but also improve the aging resistance of the material; 4. Modified boron nitride containing multiple functional groups is added to the self-made expandable microspheres as one of the raw materials. Compared with ordinary boron nitride, it is more easily dispersed, the agglomeration phenomenon is reduced, and the modified boron nitride also contains multiple functional groups, significantly enhancing the mechanical properties and aging resistance of the material, and the performance is stable.

[0025] In summary, the sheath material prepared by the present invention has stable and efficient aging resistance and mechanical properties, and has important application value in the field of cable material technology; the present invention has the advantages of good anti-aging performance, strong aging resistance, light weight, and reduced agglomeration phenomenon. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a chemical reaction schematic diagram of Intermediate Product 1 of the present invention.

[0027] Figure 2 It is a chemical reaction schematic diagram of Intermediate Product 2 of the present invention.

[0028] Figure 3 It is a graph of the relevant performance test results of the examples and comparative examples of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0029] Expansion microspheres are thermoplastic polymer microspheres containing volatile substances inside. When heated to a certain temperature, the gas inside the microspheres expands, causing its volume to increase rapidly and form a closed-cell structure. This structure can block oxygen, moisture, and other corrosive media in the external environment, helping to delay the aging process of materials and extend the service life of cables. In addition, introducing expansion microspheres into cable sheath materials can also effectively reduce the weight of the materials and make the cables lightweight.

[0030] The present invention will be further described below in conjunction with embodiments and / or drawings. Example 1

[0031] As Figures 1-3 shown, prepare modified boron nitride: Step 1: Mix 9.6 g of γ-aminopropyltriethoxysilane with 50 mL of an ethanol aqueous solution (volume ratio of ethanol / water is 4:1), add acetic acid solution (mass fraction 10%) to adjust the pH of the system to 4, stir at room temperature for 20 min to fully hydrolyze γ-aminopropyltriethoxysilane; then add 1 g of boron nitride, and stir and react in a constant temperature water bath at 60 °C for 6 h. After the reaction is completed, centrifuge and separate, wash with anhydrous ethanol multiple times, dry under vacuum, and grind to obtain silane-modified boron nitride; Step 2: Add 13.6 g of pentaerythritol and 100 mL of toluene into a three-necked flask equipped with a thermometer, an electromagnetic stirrer, a spherical condenser, and a tail gas treatment device. Slowly drip 29.2 g of phosphorus trichloride into the flask using a constant pressure dropping funnel. After the dropping is completed, heat the device. When the temperature reaches 78 °C, keep the temperature constant and reflux for 3 h. After the reaction is completed, distill off the solvent benzene and excess phosphorus trichloride under reduced pressure to obtain intermediate product 1; Step 3: Add 28.3 g of intermediate product 1 and 50 mL of acetone into a three-necked flask equipped with a magnetic stirrer, a condenser, and a thermometer. Dissolve 21.5 g of 2,4-dihydroxybenzophenone and 3.9 g of sodium hydroxide in 50 mL of acetone and 20 mL of distilled water respectively, stir and mix evenly, and then add them into the flask in sequence. Heat the device. When the temperature reaches 60 °C, keep the temperature constant and reflux for 4 h. After the reaction is completed, filter by suction, and wash the filter residue with distilled water and ethanol multiple times to obtain intermediate product 2; Step 4: Mix 1 g of silane-modified boron nitride with 100 mL of N,N-dimethylformamide, and ultrasonically treat to make the silane-modified boron nitride disperse evenly. Then add 8.6 g of intermediate product 2 and 4.2 g of triethylamine. Stir magnetically at room temperature for 4 h, then ultrasonically at 55 °C in a water bath for 4 h, and then remove the water bath and stir magnetically at room temperature for 6 h. After the reaction is completed, filter by suction, take the filter residue, wash with anhydrous ethanol multiple times, dry, and grind to obtain modified boron nitride. Example 2

[0032] Preparation of Expanded Microspheres: A1: Add 23 g of methyl methacrylate, 19 g of butyl acrylate, 20 g of methacrylic acid and 4 g of sodium dodecyl sulfate to 80 g of deionized water, mix and stir evenly, then add 8 g of the modified boron nitride prepared in Example 1, mechanically stir for 20 min and then place in an ice bath for ultrasonic treatment for 10 min to form an emulsion; A2: Add 0.2 g of potassium persulfate to the emulsion, and introduce nitrogen as a protective gas. In a water bath at 60 °C, mechanically stir and react for 12 h to obtain a product. After centrifuging the product, wash it with pure water and ethanol several times in sequence, and dry it to obtain expanded microspheres. Example 3

[0033] Preparation of Expanded Microspheres: A1: Add 31 g of methyl methacrylate, 25 g of butyl acrylate, 28 g of methacrylic acid and 6 g of alkylphenol polyoxyethylene ether to 100 g of deionized water, mix and stir evenly, then add 16 g of the modified boron nitride prepared in Example 1, mechanically stir for 30 min and then place in an ice bath for ultrasonic treatment for 20 min to form an emulsion; A2: Add 0.4 g of potassium persulfate to the emulsion, and introduce nitrogen as a protective gas. In a water bath at 80 °C, mechanically stir and react for 24 h to obtain a product. After centrifuging the product, wash it with pure water and ethanol several times in sequence, and dry it to obtain expanded microspheres. Example 4

[0034] Preparation of Lightweight and Aging-Resistant Cable Sheath Material Based on Expanded Microspheres: Add 63 g of ethylene propylene diene monomer rubber and 22 g of chlorinated polyethylene to an open mill, conduct a primary mixing for 5 min at 100 °C, then add 13 g of the expanded microspheres prepared in Example 2, 6 g of zinc stearate, 5 g of zinc oxide, 2 g of dicumyl peroxide and 0.3 g of triallyl cyanurate, conduct a secondary mixing for 5 min at 140 °C. After the mixing is completed, a mixed rubber is obtained. Vulcanize the mixed rubber in a flat vulcanizer to obtain a lightweight and aging-resistant cable sheath material based on expanded microspheres. Example 5

[0035] Preparation of Lightweight and Aging-Resistant Cable Sheath Material Based on Expanded Microspheres: Add 69 g of ethylene propylene diene monomer rubber and 27 g of chlorinated polyethylene to an open mill, conduct a primary mixing for 10 min at 110 °C, then add 17 g of the expanded microspheres prepared in Example 2, 7 g of white paraffin wax, 6 g of zinc oxide, 3 g of dicumyl peroxide and 0.4 g of triallyl isocyanurate, conduct a secondary mixing for 10 min at 150 °C. After the mixing is completed, a mixed rubber is obtained. Vulcanize the mixed rubber in a flat vulcanizer to obtain a lightweight and aging-resistant cable sheath material based on expanded microspheres. Example 6

[0036] Prepare a lightweight and aging-resistant cable sheath material based on expandable microspheres: Add 75 g of ethylene propylene diene monomer rubber and 32 g of chlorinated polyethylene into an open mill. At 120 °C, conduct the first mixing for 10 min, then add 21 g of expandable microspheres prepared in Example 2, 8 g of polyethylene wax, 7 g of zinc oxide, 4 g of dicumyl peroxide, and 0.5 g of triallyl isocyanurate. At 160 °C, conduct the second mixing for 10 min. After the mixing is completed, obtain the mixed rubber. Vulcanize the mixed rubber in a flat vulcanizer to obtain a lightweight and aging-resistant cable sheath material based on expandable microspheres.

[0037] Comparative Example 1 Use commercially available anti-aging agents of the same mass to replace the modified boron nitride in Example 3. Keep the remaining steps unchanged. First, prepare expandable microspheres. Take the expandable microspheres of the same mass and replace the expandable microspheres in Example 6. Keep the remaining steps unchanged to prepare the material.

[0038] Comparative Example 2 Use ordinary boron nitride of the same mass to replace the modified boron nitride in Example 3. Keep the remaining steps unchanged. First, prepare expandable microspheres. Take the expandable microspheres of the same mass and replace the expandable microspheres in Example 6. Keep the remaining steps unchanged to prepare the material.

[0039] Comparative Example 3 Use commercially available ethylene propylene diene monomer cable material.

[0040] Comparative experiment analysis: Make the samples of Example 4, 5, 6 and Comparative Example 1, 2, 3 into corresponding shapes according to different test standards, and conduct the following performance tests: ① Measure the tensile strength by using the national standard GB / T 528-2009 "Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber"; ② Measure the tensile strength of the aged sample (GB / T 528-2009) by using the national standard GB / T 16585 "Test method for artificial weathering (fluorescent ultraviolet lamp) of vulcanized rubber", and calculate the tensile strength retention rate; Tensile strength retention rate = tensile strength after testing / tensile strength before testing × 100%; Measure the tensile strength (GB / T 528-2009) after placing the sample in an environment of 160 °C for 48 h of hot air oxidation, and calculate the tensile strength retention rate; ③ Measure the oxidation induction time by using the national standard GB / T 19466.6-2009; The measured results are as Figure 3 shown; From Figure 3It can be seen that the sheath material prepared in the embodiment of the present invention has better performance than the comparative example due to the addition of the expandable microspheres. Therefore, the present invention has important application value in the technical field of cable materials.

[0041] In the description of the specification, the description with reference to terms such as "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0042] The above content is only an example and illustration of the present invention. Those skilled in the art of the present technology can make various modifications or supplements to the described specific embodiments or use similar methods to replace them. As long as they do not deviate from the invention or exceed the scope defined by the claims of the present invention, they should all belong to the protection scope of the present invention.

Claims

1. A lightweight, aging-resistant cable sheath material based on expanded microspheres, characterized in that: The method comprises the following raw materials in parts by weight: 63-75 parts of ethylene propylene diene monomer rubber, 22-32 parts of chlorinated polyethylene, 13-21 parts of expanded microspheres, 6-8 parts of processing aids, 5-7 parts of zinc oxide, 2-4 parts of vulcanizing agents, and 0.3-0.5 parts of cross-linking aids; The raw materials of the expanded microspheres are calculated in parts by weight as follows: 23-31 parts of methyl methacrylate, 19-25 parts of butyl acrylate, 20-28 parts of methacrylic acid, 4-6 parts of emulsifier, 80-100 parts of deionized water, 8-16 parts of modified boron nitride, and 0.2-0.4 parts of potassium persulfate.

2. A lightweight, aging-resistant cable sheath material based on expanded microspheres as claimed in claim 1, characterized in that: The expanded microspheres are prepared by the following steps: A1: Add methyl methacrylate, butyl acrylate, methacrylic acid and emulsifier into deionized water and mix well, then add modified boron nitride, stir mechanically for 20-30 minutes, and then place in an ice bath for ultrasonication for 10-20 minutes to form an emulsion; A2: Potassium persulfate is added to the emulsion, and nitrogen is introduced as a protective gas. The reaction is carried out in a water bath at 60-80°C with mechanical stirring for 12-24 hours to obtain a product. The product is centrifuged, washed, and dried to obtain expanded microspheres.

3. A lightweight, aging-resistant cable sheath material based on expanded microspheres as claimed in claim 2, characterized in that: The modified boron nitride is prepared by the following steps: Step 1: Mix γ-aminopropyltriethoxysilane with ethanol aqueous solution, adjust the pH of the system to 4-5, stir at room temperature for 20 minutes, then add boron nitride, stir and react at 60°C for 6 hours, and the reaction is completed to obtain silane-modified boron nitride; Step 2: Pentaerythritol and toluene are added into a flask, and phosphorus trichloride is added dropwise into the flask. After the addition is complete, the mixture is refluxed at 78° C. for 3 h. After the reaction is complete, the mixture is distilled under reduced pressure to obtain an intermediate product 1. Step 3: Add the intermediate product 1 and acetone into a flask, then dissolve 2,4-dihydroxybenzophenone and sodium hydroxide in acetone and distilled water respectively, stir and mix, then add them into the flask in sequence, and reflux at 60° C. for 4 hours. The reaction is completed to obtain the intermediate product 2; Step 4: Mix the silane-modified boron nitride and N,N-dimethylformamide, and then add the intermediate 2 and triethylamine. Then, stir magnetically for 4 h at room temperature. After ultrasonic treatment at 55°C for 4 h, stir at room temperature for 6 h. The reaction is completed to obtain modified boron nitride.

4. A lightweight, aging-resistant cable sheath material based on expanded microspheres as claimed in claim 3, characterized in that: The ratio of the amount of γ-aminopropyltriethoxysilane, ethanol aqueous solution and boron nitride in step 1 is 9.6 g:50 mL:1 g.

5. A lightweight, aging-resistant cable sheath material based on expanded microspheres as claimed in claim 3, characterized in that: The ratio of pentaerythritol, toluene and phosphorus trichloride used in step 2 is 13.6 g:100 mL:29.2 g.

6. A lightweight, aging-resistant cable sheath material based on expanded microspheres as claimed in claim 3, characterized in that: The ratio of the intermediate product 1, acetone, 2,4-dihydroxybenzophenone, sodium hydroxide and distilled water in step 3 is 28.3 g:100 mL:21.5 g:3.9 g:20 mL.

7. A lightweight, aging-resistant cable sheath material based on expanded microspheres as claimed in claim 3, characterized in that: In the step 4, the ratio of the amount of silane-modified boron nitride, N,N-dimethylformamide, intermediate product 2, and triethylamine is 1 g:100 mL:8.6 g:4.2 g.

8. A method for preparing a lightweight, aging-resistant cable sheath material based on expanded microspheres according to any one of claims 1 to 7, characterized in that: The following steps are involved: EPDM rubber and chlorinated polyethylene are added to an open mill for primary mixing, and then expanded microspheres, a processing aid, zinc oxide, a vulcanizing agent and a cross-linking agent are added for secondary mixing. After the mixing is completed, vulcanization is performed to obtain a lightweight, aging-resistant cable sheath material based on expanded microspheres.

9. The method for preparing a lightweight, aging-resistant cable sheath material based on expanded microspheres according to claim 8, characterized in that: The vulcanizing agent is dicumyl peroxide; the auxiliary cross-linking agent is one of triallyl cyanurate and triallyl isocyanurate; and the processing aid is one of zinc stearate, white paraffin, stearic acid and polyethylene wax.

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