Oil-resistant weather-resistant cable sheath material and preparation method thereof

Abstract

The invention relates to the field of cable sheath materials, in particular to an oil-resistant and weather-resistant cable sheath material and a preparation method thereof. The cable sheath material comprises the following raw materials in parts by weight: 80-90 parts of polyvinyl chloride resin, 25-30 parts of nitrile rubber, 20-30 parts of a filler, 40-55 parts of a plasticizer, 10-12 parts of chlorinated polyethylene CPE, 5-15 parts of a flame retardant, 3-10 parts of modified carbon nanotubes, 3-8 parts of a stabilizer, 0.5-1 part of carbon black and 0.3-1 part of a lubricant. The cable sheath material has excellent weather resistance, flame retardance and mechanical strength.

Description

Technical Field

[0001] This invention relates to the field of cable sheath materials, and more particularly to an oil-resistant and weather-resistant cable sheath material and its preparation method. Background Technology

[0002] With the deepening of energy conservation and emission reduction efforts, the wind power new energy industry has ushered in a period of rapid development. The unique environment of wind farms places higher demands on the performance of cable sheath materials. Although polyvinyl chloride (PVC) resin is widely used as a cable sheath substrate due to its low cost and corrosion resistance, its insufficient oil resistance limits its application. Nitrile rubber, with its polar cyano groups and unsaturated double bond structure in its molecular chain, can significantly improve the oil resistance and mechanical strength of composite materials, providing an effective way to enhance the performance of PVC cable sheath materials.

[0003] Furthermore, wind power cable sheath materials are exposed to complex and harsh outdoor environments for extended periods, continuously withstanding the effects of ultraviolet radiation, temperature fluctuations, and wind and rain erosion. Therefore, they must possess excellent weather resistance to ensure long-term reliability. Simultaneously, considering that wind power cables are often densely laid in large wind farms, a fire caused by an electrical fault or external ignition source could easily spread rapidly along the cable, leading to a major safety accident. Therefore, excellent flame retardancy is also indispensable. In summary, to meet the multiple performance requirements of oil resistance, weather resistance, and flame retardancy, it is necessary to optimize the formula to improve the overall performance of the cable sheath material. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, one of the objectives of this invention is to provide an oil-resistant and weather-resistant cable sheath material with excellent oil resistance, weather resistance and flame retardancy.

[0005] The second objective of this invention is to provide a method for preparing an oil-resistant and weather-resistant cable sheath material that is easy to operate.

[0006] One of the objectives of this invention is achieved through the following technical solution: An oil-resistant and weather-resistant cable sheath material, by weight, comprises the following raw materials: 80-90 parts of polyvinyl chloride resin, 25-30 parts of nitrile rubber, 20-30 parts of filler, 40-55 parts of plasticizer, 10-12 parts of chlorinated polyethylene (CPE), 5-15 parts of flame retardant, 3-10 parts of modified carbon nanotubes, 3-8 parts of stabilizer, 0.5-1 part of carbon black, and 0.3-1 part of lubricant.

[0007] Furthermore, the preparation process of the flame retardant is as follows: (1) Add 2-amino-1,3,5-triazine and formaldehyde solution to ethanol, stir, add 4-ethynylcyclohexane-1-one, adjust pH and react, purify after reaction to obtain intermediate 1; The structural formula of intermediate 1 is: (2) The intermediates 1, 1,3,5-triazidobenzene, triethylamine and cuprous chloride were added to N,N-dimethylformamide and irradiated. After the reaction was completed, the mixture was purified to obtain the flame retardant. The structural formula of the flame retardant is: .

[0008] This invention obtains intermediate 1 by a Mannich reaction of 4-ethynylcyclohexane-1-one, 2-amino-1,3,5-triazine and formaldehyde, and further utilizes the alkynyl group of intermediate 1 and 1,3,5-triazidobenzene to conduct a click chemical reaction to prepare a flame retardant.

[0009] Furthermore, the molar ratio of 4-ethynylcyclohexane-1-one, 2-amino-1,3,5-triazine, and formaldehyde in step (1) is 1:(2-2.2):(2.4-2.8).

[0010] Furthermore, in step (1), the concentration of the formaldehyde solution is 37 wt%; the pH is adjusted to 3.5-4; the stirring temperature is 60-65℃ and the time is 45-60 min; the reaction temperature is 70-80℃ and the time is 8-12 h.

[0011] Furthermore, in step (2), the ratio of 1,3,5-triazidobenzene, intermediate 1, triethylamine, and cuprous chloride is 1:(5-6):(4.5-5):(0.027-0.032); the irradiation reaction time is 10-30 min.

[0012] Furthermore, the preparation process of the modified carbon nanotubes is as follows: (a) Perfluoropentanal hydrate was added to ethanol, followed by the addition of aminated carbon nanotubes. The mixture was then dispersed by ultrasonication and reacted. After the reaction was completed, the mixture was purified to obtain Schiff base carbon nanotubes. (b) 2,6-Di-tert-butyl-4-chlorophenol was added to diethyl ether, and a hexane solution of n-butyllithium was added at -78°C and stirred. Schiff base carbon nanotubes were added and the reaction continued. After the reaction was completed, the modified carbon nanotubes were purified to obtain the modified carbon nanotubes.

[0013] This invention generates Schiff base carbon nanotubes by reacting perfluoropentanal hydrate and aminated carbon nanotubes, and then obtains modified carbon nanotubes by reacting 2,6-di-tert-butyl-4-chlorophenol with Schiff base.

[0014] Furthermore, in step (a), the mass ratio of the aminated carbon nanotubes to the perfluoropentanal hydrate is 1:(1.3-2.6); the ultrasonic dispersion time is 10-20 min; the reaction temperature is 30-50℃ and the reaction time is 2-4 h.

[0015] Furthermore, in step (b), the mass ratio of Schiff base carbon nanotubes, 2,6-di-tert-butyl-4-chlorophenol, and n-butyllithium is 1:(2.4-4.8):(0.6-1.2); the concentration of the hexane solution of n-butyllithium is 2.5 mol / L; the stirring time is 30-45 min; and the reaction continues for 3-5 h.

[0016] Furthermore, the filler is composed of calcium carbonate and kaolin in a mass ratio of 2:1; the plasticizer is purified terephthalic acid; the stabilizer is calcium-zinc composite stabilizer 90224; and the lubricant is selected from polyethylene wax, zinc stearate, and calcium stearate.

[0017] Furthermore, the polyvinyl chloride resin is PVC resin S-70; the nitrile rubber is nitrile P83; and the lubricant is polyethylene wax.

[0018] The second objective of this invention is achieved by the following technical solution: The preparation method of the above-mentioned oil-resistant and weather-resistant cable sheath material includes the following steps: Mix the raw materials according to the stated weight proportions at 100-110℃ for 10-30 minutes, then melt extrude and granulate.

[0019] Furthermore, the temperature range of each zone of the twin-screw extruder during melt extrusion is 100-150°C.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The oil-resistant and weather-resistant cable sheath material of the present invention uses polyvinyl chloride resin and nitrile rubber as the main raw materials, which has both excellent mechanical strength and oil resistance, as well as excellent weather resistance and flame retardancy.

[0021] 2. The flame retardant of this invention can improve the flame retardant performance and UV aging resistance of materials. The mechanism of action of the flame retardant is as follows: On the one hand, the benzene ring in the flame retardant molecule is structurally stable at high temperatures and can serve as the core skeleton for char formation; the triazine ring and triazole ring can undergo self-crosslinking and catalytic crosslinking reactions when heated, promoting the formation of a continuous and dense char layer in the polymer matrix; the ketone group and imine group can form additional char precursors during pyrolysis, improving the quality of the char layer. This dense char layer can effectively block heat transfer to the interior of the material and isolate oxygen from contact with internal combustible substances, thereby inhibiting the continued combustion. On the other hand, the triazine ring and triazole ring in the flame retardant molecule are rich in nitrogen, which releases a large amount of inert gases such as ammonia and nitrogen during thermal decomposition, diluting the concentration of oxygen and combustible gases in the combustion zone and inhibiting the combustion process. At the same time, the released nitrogen-containing free radicals (such as ·NH2, ·N3) can capture active free radicals such as ·H and ·OH in the combustion chain reaction, interrupting the chain transmission of oxidation reaction and further enhancing the flame retardant effect. In addition, the triazole ring contained in this flame retardant has a strong UV absorption and conversion ability, which can significantly improve the weather resistance of the material by synergistic modification of carbon nanotubes; while the ketone group, -NH- and nitrogen-containing heterocycles can form polar interactions or hydrogen bonds with the chlorine atoms of polyvinyl chloride and the nitrile groups of nitrile rubber, thereby improving its compatibility and dispersibility.

[0022] 3. The modified carbon nanotubes of this invention can improve the mechanical strength and weather resistance of materials. Specifically, this invention, through modification, simultaneously introduces fluoroalkyl chains and hindered phenolic structures onto the surface of carbon nanotubes, constructing a multi-layered weather protection system: the fluoroalkyl chains and the carbon nanotubes themselves have excellent light reflection / scattering capabilities, which can block most ultraviolet rays at the material surface. At the same time, the carbon nanotubes can efficiently convert the absorbed ultraviolet light into heat energy dissipation, avoiding photo-oxidative degradation of polymer chains; the strong hydrophobicity and low surface energy of the fluoroalkyl chains can form a dense physical barrier on the material surface, effectively hindering the penetration of oxygen, moisture, and corrosive ions, and inhibiting the synergistic effect of thermo-oxidative aging and photo-oxidative aging under high temperature and high humidity conditions. The two-dimensional sheet structure of the carbon nanotubes further extends the diffusion path and strengthens the barrier effect; the hindered phenolic structure acts as a highly efficient free radical scavenger, preferentially scavenging alkyl free radicals and peroxy free radicals generated by photo / thermal aging, blocking the oxidation chain reaction. The three work synergistically to form a closed-loop protection network of "shielding-blocking-scavenging", significantly improving the aging resistance of the material. In addition, the polarity of the fluoroalkyl chains on the surface of the modified carbon nanotubes is similar to that of polyvinyl chloride (PVC), which can generate strong van der Waals forces with PVC segments, thereby helping to improve its interfacial compatibility and dispersibility. At the same time, the fluoroalkyl chains are oleophobic, further improving the oil resistance of the material, and the nano-reinforcing effect of the carbon nanotubes also helps to improve the mechanical strength of the material. Attached Figure Description

[0023] Figure 1This is the infrared spectrum of the modified carbon nanotubes prepared in Example 4. Detailed Implementation

[0024] The present invention will now be further described with reference to the accompanying drawings and specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments. Specific conditions not specified in the embodiments are performed according to conventional conditions or conditions recommended by the manufacturer. Unless otherwise specified, all reagents or instruments used are conventional products obtained through commercial channels.

[0025] The filler of this invention is composed of calcium carbonate and kaolin in a mass ratio of 2:1; the plasticizer is purified terephthalic acid; the stabilizer is calcium-zinc composite stabilizer 90224; the lubricant is polyethylene wax; the polyvinyl chloride resin is PVC resin S-70; and the nitrile rubber is nitrile P83.

[0026] (a) Preparation example Preparation Example 1 This preparation example provides a flame retardant, and the preparation process is as follows: (1) Using 4-ethynylcyclohexane-1-one, 2-amino-1,3,5-triazine, formaldehyde, and ethanol in a ratio of 0.01 mol: 0.021 mol: 0.025 mol: 90 mL, 2-amino-1,3,5-triazine and a 37 wt% formaldehyde solution were added to ethanol. After stirring at 63 °C for 50 min, 4-ethynylcyclohexane-1-one was added. The pH was adjusted to 3.7 using 1 mol / L hydrochloric acid solution, and then the temperature was raised to 75 °C and reacted for 10 h. After the reaction was completed, the reaction solution was cooled to room temperature, filtered, and the solid product was washed with ethanol and dried under vacuum to obtain intermediate 1. The NMR and mass spectrometry results of intermediate 1 are as follows: 1 HNMR: (C 16 H 18 ON8, 400MHz, DMSO-d6) δ: 1.78-1.82 (m, 2H), 2.04-2.08 (m, 2H), 2.27-2.33 (m, 3H), 2 .62-2.66 (m, 1H), 2.83-2.87 (m, 2H), 3.08-3.12 (m, 2H), 7.01 (s, 2H), 9.28 (s, 4H); MS (ESI) m / z=338.16 [M].

[0027] (2) The ratio of 1,3,5-triazidobenzene, intermediate 1, triethylamine, cuprous chloride, and DMF was 1 mmol: 5.5 mmol: 4.6 mmol: 0.03 mmol: 14 mL. 1,3,5-triazidobenzene (CAS: 13556-15-5), intermediate 1, triethylamine, and cuprous chloride were added to N,N-dimethylformamide (DMF) and mixed evenly. The mixture was then irradiated with microwave at 400 W for 20 min. After the reaction was completed, the reaction solution was extracted with ethyl acetate, the organic layer was washed with saturated brine, dried over anhydrous sodium sulfate, concentrated by rotary evaporation, and purified by column chromatography to obtain the flame retardant. The NMR and mass spectrometry results of the flame retardant are as follows: 1 HNMR: (C 54 H 57 O3N 33 , 400MHz, DMSO-d6) δ: 2.04-2.08 (m, 6H), 2.11-2.15 (m, 6H), 2.27-2.33 (m, 6H), 2.83-2 .90 (m, 9H), 3.08-3.12 (m, 6H), 7.01 (s, 6H), 7.33 (s, 3H), 8.08 (s, 3H), 9.28 (s, 12H); MS (ESI) m / z=1215.53 [M].

[0028] Preparation Example 2 This preparation example provides a flame retardant, and the preparation process is as follows: (1) The ratio of 4-ethynylcyclohexane-1-one, 2-amino-1,3,5-triazine, formaldehyde and ethanol was 0.01 mol: 0.022 mol: 0.028 mol: 100 mL. 2-amino-1,3,5-triazine and 37 wt% formaldehyde solution were added to ethanol. After stirring at 65 °C for 45 min, 4-ethynylcyclohexane-1-one was added. The pH was adjusted to 4 with 1 mol / L hydrochloric acid solution. Then the temperature was raised to 80 °C and reacted for 8 h. After the reaction was completed, the reaction solution was cooled to room temperature, filtered, and the solid product was washed with ethanol and dried under vacuum to obtain intermediate 1. The NMR and mass spectrometry results of intermediate 1 were the same as those of preparation example 1. (2) The ratio of 1,3,5-triazidobenzene, intermediate 1, triethylamine, cuprous chloride, and DMF was 1 mmol: 6 mmol: 5 mmol: 0.032 mmol: 20 mL. 1,3,5-triazidobenzene, intermediate 1, triethylamine, and cuprous chloride were added to DMF and mixed evenly. The mixture was irradiated with microwave at 400 W for 30 min. After the reaction was completed, the reaction solution was extracted with ethyl acetate, the organic layer was washed with saturated brine, dried with anhydrous sodium sulfate, concentrated by rotary evaporation, and purified by column chromatography to obtain the flame retardant. The NMR and mass spectrometry results of the flame retardant were the same as those in Preparation Example 1.

[0029] Preparation Example 3 This preparation example provides a flame retardant, and the preparation process is as follows: (1) The ratio of 4-ethynylcyclohexane-1-one, 2-amino-1,3,5-triazine, formaldehyde and ethanol was 0.01mol:0.02mol:0.024mol:80mL. 2-amino-1,3,5-triazine and formaldehyde solution with a concentration of 37wt% were added to ethanol. After stirring at 60℃ for 60min, 4-ethynylcyclohexane-1-one was added. The pH was adjusted to 3.5 with 1mol / L hydrochloric acid solution. Then the temperature was raised to 70℃ and reacted for 12h. After the reaction was completed, the reaction solution was cooled to room temperature, filtered, and the solid product was washed with ethanol and dried under vacuum to obtain intermediate 1. The NMR and mass spectrometry results of intermediate 1 were the same as those of preparation example 1. (2) The ratio of 1,3,5-triazidobenzene, intermediate 1, triethylamine, cuprous chloride, and DMF was 1 mmol: 5 mmol: 4.5 mmol: 0.027 mmol: 10 mL. 1,3,5-triazidobenzene, intermediate 1, triethylamine, and cuprous chloride were added to DMF and mixed evenly. The mixture was irradiated with microwave at 400 W for 10 min. After the reaction was completed, the reaction solution was extracted with ethyl acetate, the organic layer was washed with saturated brine, dried with anhydrous sodium sulfate, concentrated by rotary evaporation, and purified by column chromatography to obtain the flame retardant. The NMR and mass spectrometry results of the flame retardant were the same as those in Preparation Example 1.

[0030] Preparation Example 4 This preparation example provides a modified carbon nanotube, and the preparation process is as follows: (a) With the amounts of aminated carbon nanotubes, perfluoropentaldehyde hydrate, and ethanol being 1 g: 2 g: 50 mL, the perfluoropentaldehyde hydrate was dissolved in ethanol, the aminated carbon nanotubes were added, ultrasonically dispersed for 15 min, and reacted at 40 °C for 3 h. After the reaction was completed, the mixture was filtered, washed successively with ethanol and deionized water, and vacuum dried to obtain Schiff base carbon nanotubes. (b) The modified carbon nanotubes were prepared by using Schiff base carbon nanotubes, 2,6-di-tert-butyl-4-chlorophenol, n-butyllithium, and diethyl ether in a ratio of 1 g: 3 g: 1 g: 60 mL. 2,6-di-tert-butyl-4-chlorophenol was dissolved in diethyl ether, and a hexane solution of n-butyllithium with a concentration of 2.5 mol / L was added at -78 °C. After stirring for 35 min, Schiff base carbon nanotubes were added and dispersed evenly. The reaction was continued for 4 h. The reaction was quenched by adding saturated ammonium chloride aqueous solution. The mixture was filtered, washed with diethyl ether and deionized water, and dried under vacuum to obtain the modified carbon nanotubes.

[0031] Preparation Example 5 This preparation example provides a modified carbon nanotube, and the preparation process is as follows: (a) With the amounts of aminated carbon nanotubes, perfluoropentaldehyde hydrate, and ethanol being 1 g: 2.6 g: 60 mL, the perfluoropentaldehyde hydrate was dissolved in ethanol, the aminated carbon nanotubes were added, ultrasonically dispersed for 20 min, and reacted at 50 °C for 2 h. After the reaction was completed, the mixture was filtered, washed successively with ethanol and deionized water, and vacuum dried to obtain Schiff base carbon nanotubes. (b) The modified carbon nanotubes were prepared by using Schiff base carbon nanotubes, 2,6-di-tert-butyl-4-chlorophenol, n-butyllithium, and diethyl ether in a ratio of 1 g: 4.8 g: 1.2 g: 80 mL. 2,6-di-tert-butyl-4-chlorophenol was dissolved in diethyl ether, and a hexane solution of n-butyllithium with a concentration of 2.5 mol / L was added at -78 °C. After stirring for 45 min, Schiff base carbon nanotubes were added and dispersed evenly. The reaction was continued for 5 h, and the reaction was quenched by adding saturated ammonium chloride aqueous solution. The mixture was filtered, washed with diethyl ether and deionized water, and dried under vacuum to obtain the modified carbon nanotubes.

[0032] Preparation Example 6 This preparation example provides a modified carbon nanotube, and the preparation process is as follows: (a) With the amounts of aminated carbon nanotubes, perfluoropentaldehyde hydrate, and ethanol being 1 g: 1.3 g: 40 mL, the perfluoropentaldehyde hydrate was dissolved in ethanol, the aminated carbon nanotubes were added, ultrasonically dispersed for 10 min, and reacted at 30 °C for 4 h. After the reaction was completed, the mixture was filtered, washed successively with ethanol and deionized water, and vacuum dried to obtain Schiff base carbon nanotubes. (b) The modified carbon nanotubes were prepared by using Schiff base carbon nanotubes, 2,6-di-tert-butyl-4-chlorophenol, n-butyllithium, and diethyl ether in a ratio of 1 g: 2.4 g: 0.6 g: 50 mL. 2,6-di-tert-butyl-4-chlorophenol was dissolved in diethyl ether, and a hexane solution of n-butyllithium with a concentration of 2.5 mol / L was added at -78 °C. After stirring for 30 min, Schiff base carbon nanotubes were added and dispersed evenly. The reaction was continued for 3 h, and the reaction was quenched by adding saturated ammonium chloride aqueous solution. The mixture was filtered, washed with diethyl ether and deionized water, and dried under vacuum to obtain the modified carbon nanotubes.

[0033] (II) Implementation Examples Example 1 This embodiment provides an oil-resistant and weather-resistant cable sheath material, which, by weight, comprises the following raw materials: 84 parts of polyvinyl chloride resin, 29 parts of nitrile rubber, 25 parts of filler, 50 parts of plasticizer, 11 parts of chlorinated polyethylene (CPE), 10 parts of flame retardant from Preparation Example 1, 7 parts of modified carbon nanotubes from Preparation Example 4, 6 parts of stabilizer, 0.8 parts of carbon black, and 0.5 parts of lubricant.

[0034] This embodiment also provides a method for preparing the above-mentioned oil-resistant and weather-resistant cable sheath material, including the following steps: Weigh each raw material according to the stated weight proportions, mix them at 105°C for 20 minutes, transfer them to a twin-screw extruder, adjust the temperature range of each zone to 100-150°C, melt extrude and then granulate.

[0035] Example 2 This embodiment provides an oil-resistant and weather-resistant cable sheath material, which, by weight, comprises the following raw materials: 80 parts of polyvinyl chloride resin, 25 parts of nitrile rubber, 20 parts of filler, 40 parts of plasticizer, 10 parts of chlorinated polyethylene (CPE), 5 parts of flame retardant from Preparation Example 2, 3 parts of modified carbon nanotubes from Preparation Example 5, 3 parts of stabilizer, 0.5 parts of carbon black, and 0.3 parts of lubricant.

[0036] This embodiment also provides a method for preparing the above-mentioned oil-resistant and weather-resistant cable sheath material, including the following steps: Weigh each raw material according to the stated weight proportions, mix them at 100°C for 30 minutes, transfer them to a twin-screw extruder, adjust the temperature range of each zone to 100-150°C, melt extrude and then granulate.

[0037] Example 3 This embodiment provides an oil-resistant and weather-resistant cable sheath material, which, by weight, includes the following raw materials: 90 parts of polyvinyl chloride resin, 30 parts of nitrile rubber, 30 parts of filler, 55 parts of plasticizer, 12 parts of chlorinated polyethylene (CPE), 15 parts of flame retardant (Preparation Example 3), 10 parts of modified carbon nanotubes (Preparation Example 6), 8 parts of stabilizer, 1 part of carbon black, and 1 part of lubricant.

[0038] This embodiment also provides a method for preparing the above-mentioned oil-resistant and weather-resistant cable sheath material, including the following steps: Weigh each raw material according to the stated weight proportions, mix them at 110°C for 10 minutes, transfer them to a twin-screw extruder, adjust the temperature range of each zone to 100-150°C, melt extrude and then granulate.

[0039] (III) Comparative Example Comparative Example 1 The difference between this comparative example and Example 1 is that the flame retardant used in Example 1 is omitted.

[0040] Comparative Example 2 The difference between this comparative example and Example 1 is that the modified carbon nanotubes in Preparation Example 4 were replaced with carbon nanotubes.

[0041] (iv) Experimental Examples The modified carbon nanotubes prepared in Example 4 were analyzed by Fourier transform infrared spectroscopy (FT-IR), and the results are as follows: Figure 1 As shown.

[0042] Figure 1The images show the infrared spectra of the modified carbon nanotubes prepared in Example 4. Curve 1 is the spectrum of the aminated carbon nanotubes; curve 2 is the spectrum of the Schiff base carbon nanotubes; and curve 3 is the spectrum of the modified carbon nanotubes. (Observation) Figure 1 It is known that, compared to aminated carbon nanotubes, Schiff base carbon nanotubes have a higher growth rate at 3500 cm⁻¹. -1 The characteristic absorption peak of the amino group around the 1643 cm⁻¹ decreases, and then decreases to around 1643 cm⁻¹. -1 The presence of a characteristic C=N absorption peak at 3500 cm⁻¹ indicates the successful preparation of Schiff base carbon nanotubes. Compared to Schiff base carbon nanotubes, the modified carbon nanotubes exhibit a higher absorption peak at 3500 cm⁻¹ due to the introduction of hydroxyl groups from the 2,6-di-tert-butyl-4-chlorophenol molecule. -1 The characteristic absorption peaks on the left and right sides are enhanced, especially at 3000 cm⁻¹. -1 and 1508 cm -1 The characteristic absorption peaks of the methyl and benzene ring skeleton in the 2,6-di-tert-butyl-4-chlorophenol molecule appear at 1643 cm⁻¹. -1 The disappearance of the characteristic absorption peak at C=N indicates that the modified carbon nanotubes were successfully prepared.

[0043] (v) Examples of Results The performance of the materials prepared according to the embodiments and comparative examples of the present invention is tested in the following details: Oxygen index: Tested according to GB / T 2406.1-2008, the results are shown in Table 1; Tensile strength: Tested according to GB / T 1040.1-2018, the results are shown in Table 1; Heat resistance: Tested according to GB / T 3512-2014, the test conditions were: 120℃, time was 240 h, and the heat resistance was measured by the retention rate of elongation at break. The results are shown in Table 1. UV aging resistance: Tested according to GB / T 16585-1996, the test conditions were: time was 70 days, and the retention rate of elongation at break was used to measure UV aging resistance. The results are shown in Table 1. Seawater resistance: Tested according to GB / T 1690-2010, the test conditions are: artificial seawater, 60℃, time is 240h, and the seawater resistance is measured by the retention rate of elongation at break. The results are shown in Table 1. Oil resistance: Tested according to GB / T 2951.21-2008, the test conditions were: IRM902 oil, 100℃, time was 24h, and the oil resistance was measured by the retention rate of elongation at break. The results are shown in Table 1.

[0044] As shown in Table 1, the material prepared in Example 1 has excellent oil resistance, weather resistance, flame retardancy and mechanical strength.

[0045] Compared to Example 1, the flame retardant performance and UV aging resistance of the material obtained by omitting the flame retardant in Comparative Example 1 are reduced. This experimental result demonstrates that the flame retardant of the present invention can improve the flame retardant performance and UV aging resistance of the material. The mechanism of action of the flame retardant of the present invention is as follows: On the one hand, the benzene ring in the flame retardant molecule is structurally stable at high temperatures and can serve as the core framework for char formation; the triazine ring and triazole ring can undergo self-crosslinking and catalytic crosslinking reactions when heated, promoting the formation of a continuous and dense char layer in the polymer matrix; the ketone group and imine group can form additional char precursors during pyrolysis, improving the quality of the char layer. This dense char layer can effectively block heat transfer to the interior of the material and isolate oxygen from contact with the internal combustible substances, thereby inhibiting the continued combustion. On the other hand, the triazine ring and triazole ring in the flame retardant molecule are rich in nitrogen, which releases a large amount of inert gases such as ammonia and nitrogen during thermal decomposition, diluting the concentration of oxygen and combustible gases in the combustion zone and inhibiting the combustion process. Meanwhile, the released nitrogen-containing free radicals (such as ·NH2 and ·N3) can capture active free radicals such as ·H and ·OH in the combustion chain reaction, interrupt the chain transmission of the oxidation reaction, and further enhance the flame retardant effect.

[0046] In addition, the triazole ring contained in this flame retardant has a strong UV absorption and conversion ability, which can significantly improve the weather resistance of the material by synergistic modification of carbon nanotubes; while the ketone group, -NH- and nitrogen-containing heterocycles can form polar interactions or hydrogen bonds with the chlorine atoms of polyvinyl chloride and the nitrile groups of nitrile rubber, thereby improving its compatibility and dispersibility.

[0047] Compared to Example 1, the material obtained using carbon nanotubes in Comparative Example 2 showed significantly reduced mechanical strength and weather resistance. This experimental result demonstrates that the modified carbon nanotubes of the present invention can improve the mechanical strength and weather resistance of materials. Specifically, the present invention, through modification, simultaneously introduces fluoroalkyl chains and hindered phenolic structures onto the surface of carbon nanotubes, constructing a multi-layered weather protection system: the fluoroalkyl chains and the carbon nanotubes themselves possess excellent light reflection / scattering capabilities, which can block most ultraviolet rays at the material surface. At the same time, the carbon nanotubes can efficiently convert absorbed ultraviolet light into heat energy dissipation, avoiding photo-oxidative degradation of polymer chains; the strong hydrophobicity and low surface energy of the fluoroalkyl chains can form a dense physical barrier on the material surface, effectively hindering the penetration of oxygen, moisture, and corrosive ions, and suppressing the synergistic effect of thermo-oxidative aging and photo-oxidative aging under high temperature and high humidity conditions. The two-dimensional layered structure of the carbon nanotubes further extends the diffusion path and strengthens the barrier effect; the hindered phenolic structure acts as a highly efficient free radical scavenger, preferentially scavenging alkyl free radicals and peroxy free radicals generated by photo / thermal aging, blocking the oxidation chain reaction. The three elements work together to form a closed-loop protection network of "shielding-blocking-removal", which significantly improves the aging resistance of the material.

[0048] In addition, the polarity of the fluoroalkyl chains on the surface of the modified carbon nanotubes is similar to that of polyvinyl chloride (PVC), which can generate strong van der Waals forces with PVC segments, thereby helping to improve its interfacial compatibility and dispersibility. At the same time, the fluoroalkyl chains are oleophobic, further improving the oil resistance of the material, and the nano-reinforcing effect of the carbon nanotubes also helps to improve the mechanical strength of the material.

[0049] The above embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. An oil-resistant and weather-resistant cable sheath material, characterized in that, The raw materials include: polyvinyl chloride resin, nitrile rubber, filler, plasticizer, chlorinated polyethylene (CPE), flame retardant, modified carbon nanotubes, stabilizer, carbon black, and lubricant.

2. The oil-resistant and weather-resistant cable sheath material according to claim 1, characterized in that, By weight, it includes the following raw materials: 80-90 parts polyvinyl chloride resin, 25-30 parts nitrile rubber, 20-30 parts filler, 40-55 parts plasticizer, 10-12 parts chlorinated polyethylene (CPE), 5-15 parts flame retardant, 3-10 parts modified carbon nanotubes, 3-8 parts stabilizer, 0.5-1 part carbon black, and 0.3-1 part lubricant.

3. The oil-resistant and weather-resistant cable sheath material according to claim 1 or 2, characterized in that, The preparation process of the flame retardant is as follows: (1) Add 2-amino-1,3,5-triazine and formaldehyde solution to ethanol, stir, add 4-ethynylcyclohexane-1-one, adjust pH and react, purify after reaction to obtain intermediate 1; The structural formula of intermediate 1 is: (2) The intermediates 1, 1,3,5-triazidobenzene, triethylamine and cuprous chloride were added to N,N-dimethylformamide and irradiated. After the reaction was completed, the mixture was purified to obtain the flame retardant. The structural formula of the flame retardant is: 。 4. The oil-resistant and weather-resistant cable sheath material according to claim 3, characterized in that, In step (1), the molar ratio of 4-ethynylcyclohexane-1-one, 2-amino-1,3,5-triazine, and formaldehyde is 1:(2-2.2):(2.4-2.8); the concentration of the formaldehyde solution is 37wt%; the pH is adjusted to 3.5-4; the stirring temperature is 60-65℃ and the time is 45-60min; the reaction temperature is 70-80℃ and the time is 8-12h.

5. The oil-resistant and weather-resistant cable sheath material according to claim 3, characterized in that, In step (2), the ratio of 1,3,5-triazidobenzene, intermediate 1, triethylamine, and cuprous chloride is 1:(5-6):(4.5-5):(0.027-0.032); the irradiation reaction time is 10-30 min.

6. The oil-resistant and weather-resistant cable sheath material according to claim 1 or 2, characterized in that, The preparation process of the modified carbon nanotubes is as follows: (a) Perfluoropentanal hydrate was added to ethanol, followed by the addition of aminated carbon nanotubes. The mixture was then dispersed by ultrasonication and reacted. After the reaction was completed, the mixture was purified to obtain Schiff base carbon nanotubes. (b) 2,6-Di-tert-butyl-4-chlorophenol was added to diethyl ether, and a hexane solution of n-butyllithium was added at -78°C and stirred. Schiff base carbon nanotubes were added and the reaction continued. After the reaction was completed, the modified carbon nanotubes were purified to obtain the modified carbon nanotubes.

7. The oil-resistant and weather-resistant cable sheath material according to claim 6, characterized in that, In step (a), the mass ratio of aminated carbon nanotubes to perfluoropentanal hydrate is 1:(1.3-2.6); the ultrasonic dispersion time is 10-20 min; the reaction temperature is 30-50℃ and the reaction time is 2-4 h.

8. The oil-resistant and weather-resistant cable sheath material according to claim 6, characterized in that, In step (b), the mass ratio of Schiff base carbon nanotubes, 2,6-di-tert-butyl-4-chlorophenol, and n-butyllithium is 1:(2.4-4.8):(0.6-1.2); the concentration of the hexane solution of n-butyllithium is 2.5 mol / L; the stirring time is 30-45 min; and the reaction continues for 3-5 h.

9. The oil-resistant and weather-resistant cable sheath material according to claim 1, characterized in that, The filler is composed of calcium carbonate and kaolin in a mass ratio of 2:1; the plasticizer is purified terephthalic acid; the stabilizer is calcium-zinc composite stabilizer 90224; and the lubricant is selected from polyethylene wax, zinc stearate, and calcium stearate.

10. A method for preparing an oil-resistant and weather-resistant cable sheath material as described in any one of claims 1-9, characterized in that, Includes the following steps: Mix the raw materials according to the stated weight proportions at 100-110℃ for 10-30 minutes, then melt extrude and granulate.

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