Flame-retardant aging-resistant cable for solar power generation and preparation method thereof

Abstract

The invention discloses a flame-retardant aging-resistant cable for solar power generation and a preparation method thereof, belongs to the technical field of cable preparation, and aims to solve the technical problem that the flame retardance and ultraviolet aging resistance of a cable for solar power generation in the prior art need to be further improved. The cable comprises a conductor layer, an insulating layer, a shielding layer and an outer sheath layer, an organic copper frame copper 1, 3, 5-trimesic tricarboxylate is prepared through a hydrothermal method, titanium dioxide, zinc oxide and a double-bond structure are modified on the surface of the organic copper frame copper 1, 3, 5-trimesic tricarboxylate to obtain a composite copper frame, and the composite copper frame serves as an auxiliary agent of a modified chain extender and participates in the preparation process of modified polyvinylidene fluoride. Modified polyvinylidene chloride and auxiliary materials are subjected to melt extrusion and are naturally cured on the surface of the shielding layer to obtain the high-performance cable for solar power generation.

Description

Technical Field

[0001] The present invention relates to the technical field of cable preparation, and particularly relates to a flame-retardant and aging-resistant cable for solar power generation and a preparation method thereof. Background Art

[0002] In the early days, polyvinyl chloride materials were mostly used for solar power generation cables, with poor flame retardancy, releasing a large amount of toxic gases when burning, being prone to aging and cracking under ultraviolet irradiation, and having a short lifespan. Subsequently, the industry turned to low-smoke and halogen-free materials, such as cross-linked polyethylene, to improve thermal stability and flame retardancy through electron beam cross-linking technology, reducing the release of smoke and poisonous gases when burning. At the same time, for the problem of ultraviolet aging, ultraviolet stabilizers and anti-ultraviolet additives, such as benzotriazole compounds, were introduced to enhance the anti-photooxidation ability of the material molecular structure and extend the service life of the cable in outdoor environments. In recent years, the application of composite materials and nanotechnology, such as adding inorganic filler components, has further improved the anti-ultraviolet and flame retardant properties of the cable, ensuring its stability and safety in extreme climates and meeting the high reliability requirements of modern solar power generation systems.

[0003] For example, the prior art CN116478488B discloses an anti-aging photovoltaic cable and a preparation method thereof. A layer of anti-aging protective sleeve is extruded on the surface of the cable. By weight, it includes: 100 parts of PVC resin, 10 - 20 parts of linear low-density polyethylene, 10 - 20 parts of ethylene-octene copolymer, 2 - 5 parts of masterbatch, 5.5 - 9 parts of composite anti-aging agent, 3 - 4 parts of calcium-zinc stabilizer, 4 - 7 parts of calcium carbonate, 2 - 3 parts of stearic acid, 5 - 8 parts of epoxidized soybean oil, and 1.2 - 1.6 parts of flame retardant; the composite anti-aging agent uses a porous material composite carrier containing zinc-titanium oxide, uses a silane coupling agent as a bridging material, grafts a compound b containing an ortho-hydroxybenzophenone structure onto the surface of the composite carrier, plays a dual role of ultraviolet shielding and conversion in the PVC matrix, and at the same time fixes the compound b to achieve a long-term anti-ultraviolet aging effect.

[0004] However, the above process only uses a silane coupling agent as a bridging material to graft a compound b containing an ortho-hydroxybenzophenone structure onto the surface of the composite carrier to improve the anti-aging performance of the photovoltaic cable. However, the flame retardant mechanism of this link relies on the release of halogen radicals to interrupt combustion, lacking components to form a dense carbon layer or release non-combustible gases, resulting in difficulty in effectively isolating oxygen and heat, and limited combustion inhibition effect;

[0005] Meanwhile, the composite anti-aging agent is prepared by modifying 2,2'-dihydroxybenzophenone. Although the benzophenone structure can absorb ultraviolet energy, it does not introduce low surface energy or wide bandgap materials to enhance the inhibitory ability of photooxidative degradation. The molecular chain is easily broken by ultraviolet rays. In addition, the material system does not strengthen the molecular chain stability through a highly crosslinked network or rigid fillers, resulting in insufficient light oxidation resistance and easy aging and cracking under long-term exposure. These factors jointly limit the performance of the cable in terms of flame retardancy and anti-ultraviolet aging performance, and it is difficult to meet the usage requirements in harsh environments. Summary of the Invention

[0006] The purpose of the present invention is to provide a flame-retardant and aging-resistant cable for solar power generation and its preparation method, which is used to solve the technical problem that the flame retardancy and anti-ultraviolet aging performance of the cable for solar power generation in the prior art need to be further improved.

[0007] The purpose of the present invention can be achieved by the following technical solutions: A flame-retardant and aging-resistant cable for solar power generation, comprising a conductor layer, an insulating layer, a shielding layer, and an outer sheath layer;

[0008] Among them, the conductor layer is composed of a plurality of copper wires stranded together; the insulating layer is obtained by melt-extruding a composite polyvinyl fluoride material and curing it on the surface of the conductor layer; the shielding layer is obtained by winding a copper tape around the insulating layer; the outer sheath layer is obtained by melt-extruding a composite polyvinylidene chloride material and curing it on the surface of the shielding layer;

[0009] The composite polyvinylidene chloride material comprises the following raw materials in parts by weight: 70-80 parts of modified polyvinylidene chloride, 15-20 parts of plasticizer, 2-5 parts of stabilizer, 1-2 parts of lubricant, and 1-2 parts of antioxidant.

[0010] Further, the plasticizer is phthalic acid diester; the stabilizer is one or both of tribasic lead sulfate and dibutyltin dilaurate; the lubricant is one or both of calcium stearate and zinc stearate; the antioxidant is one or more of triphosphate ester and 2,6-di-tert-butyl-p-cresol.

[0011] Further, the preparation method of the modified polyvinylidene chloride comprises the following steps:

[0012] A1. Add trans-1,2-dichloroethylene, 2-vinyl-4,6-diamino-1,3,5-triazine, 4-trimethylsilyl-N-tert-butyl-2-buteneimine, azobisisobutyronitrile, polytetrahydrofuran, and N,N-dimethylacetamide into a high-pressure reaction kettle. Raise the temperature of the reaction kettle to 60-80 °C, keep the temperature for reaction for 1-2 h, then add a modified chain extender into the reaction kettle, keep the temperature for reaction for 30-40 min, and perform post-treatment to obtain chain-extended polyvinylidene chloride;

[0013] A2. Add chain-extended polyvinylidene chloride, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, aluminum chloride, and N,N-dimethylacetamide into a reaction kettle. Raise the temperature of the reaction kettle to 40 - 60 °C, hold the temperature for reaction for 1 - 2 h, and perform post-treatment to obtain modified polyvinylidene chloride.

[0014] The reaction equation for preparing modified polyvinylidene chloride is:

[0015]

[0016] In the formula: ; ; ; .

[0017] The reaction principle for preparing modified polyvinylidene chloride is as follows: Under the promotion of a catalyst and heating conditions, trans-1,2-dichloroethylene, 2-vinyl-4,6-diamino-1,3,5-triazine, and 4-trimethylsilyl-N-tert-butyl-2-buteneimine undergo a radical addition reaction, and the chain is extended through the double-bond structure modified on the composite copper framework in the modified chain extender to obtain chain-extended polyvinylidene chloride. Finally, through the addition of phosphoric acid, the imine structure in the modified chain extender is added to obtain modified polyvinylidene chloride.

[0018] Further, in step A1, the dosage ratio of trans-1,2-dichloroethylene, 2-vinyl-4,6-diamino-1,3,5-triazine, 4-trimethylsilyl-N-tert-butyl-2-buteneimine, azobisisobutyronitrile, polytetrahydrofuran, N,N-dimethylacetamide, and the modified chain extender is 4.5 - 5.5 g: 3.6 - 4.4 g: 4.5 - 5.5 g: 1 - 2 g: 16 - 20 mL: 30 - 36 mL: 2 - 3 g. The post-treatment includes: After the reaction is completed, wait for the temperature of the reaction kettle to drop to room temperature, transfer the reaction solution to a rotary evaporator, raise the temperature of the rotary evaporator to 60 - 80 °C, and perform vacuum distillation until no liquid is collected to obtain chain-extended polyvinylidene chloride;

[0019] Further, in step A2, the dosage ratio of the chain-extended polyvinylidene chloride, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, aluminum chloride, and N,N-dimethylacetamide is 13 - 15 g: 4.5 - 5.5 g: 1 - 2 g: 80 - 90 mL. The post-treatment includes: After the reaction is completed, wait for the temperature of the reaction kettle to drop to room temperature, transfer the reaction solution to a rotary evaporator, raise the temperature of the rotary evaporator to 60 - 80 °C, and perform vacuum distillation until no liquid is collected to obtain modified polyvinylidene chloride.

[0020] Further, the preparation method of the modified chain extender includes the following steps:

[0021] B1. Add 4-(2H-benzotriazol-2-yl)-1,3-benzenediol and N,N-dimethylformamide into a low-temperature reaction kettle. After introducing nitrogen for protection, lower the temperature of the reaction kettle to 0 - 5 °C, and dropwise add acryloyl chloride into the reaction kettle. Keep the temperature for reaction for 6 - 8 h, and perform post-treatment to obtain a modified anti-ultraviolet agent.

[0022] B2. Add the modified anti-ultraviolet agent, methylphenylvinyl silicone oil and N,N-dimethylformamide into a reaction kettle. After raising the temperature of the reaction kettle to 60 - 80 °C, add azobisisobutyronitrile into the reaction kettle. After keeping the temperature for reaction for 1 - 2 h, add 11-mercaptoundecyltrimethoxysilane into the reaction kettle. Keep the temperature for reaction for 20 - 30 min, and perform post-treatment to obtain a precursor of a modified chain extender.

[0023] B3. Add the precursor of the modified chain extender, N,N-dimethylformamide and deionized water into a reaction kettle and stir. Raise the temperature of the reaction kettle to 60 - 80 °C, and adjust the pH of the reaction system to 8 - 10 using a saturated sodium hydroxide aqueous solution. Add a composite copper framework into the reaction kettle, keep the temperature and stir for 40 - 60 min, and perform post-treatment to obtain a modified chain extender.

[0024] The reaction equation for preparing the modified chain extender is:

[0025]

[0026] In the formula:

[0027] ; ;

[0028] ; “ ” represents the composite copper framework.

[0029] The reaction principle for preparing the modified chain extender is as follows: The phenolic hydroxyl group of 4-(2H-benzotriazol-2-yl)-1,3-benzenediol has nucleophilicity and attacks the carbonyl carbon of the acyl chloride to form an ester bond, thereby preparing a modified anti-ultraviolet agent with a double bond structure. It further undergoes a radical addition reaction with methylphenylvinyl silicone oil to form a long-chain structure, and is capped by 11-mercaptoundecyltrimethoxysilane to obtain a modified chain extender precursor with siloxane modification. Through hydrolysis, silanol groups are formed, which react with the active sites on the surface of the composite copper framework, ultimately introducing the composite copper framework into the interior of the organic chain segment, thereby obtaining the modified chain extender.

[0030] Further, in step B1, the dosage ratio of 4-(2H-benzotriazol-2-yl)-1,3-benzenediol, N,N-dimethylformamide and acryloyl chloride is 6.0 - 7.5 g : 36 - 40 mL : 2.4 - 3.0 g. The post-treatment includes: after the reaction is completed, add an equal volume of saturated sodium bicarbonate solution to the reaction solution, stir for 5 - 6 min, and after the solution is layered, take the upper layer liquid. Then add an equal volume of absolute ethanol to the upper layer liquid, transfer the solution to a rotary evaporator, raise the temperature of the rotary evaporator to 60 - 80 °C, and distill under reduced pressure until no liquid is collected, to obtain the modified anti-ultraviolet agent;

[0031] Further, in step B2, the dosage ratio of the modified anti-ultraviolet agent, methylphenylvinylsilicone oil, N,N-dimethylformamide, azobisisobutyronitrile and 11-mercaptoundecyltrimethoxysilane is 8 - 10 g : 5 - 6 g : 80 - 90 mL : 1 - 2 g : 1 - 2 g. The post-treatment includes: after the reaction is completed, wait for the temperature of the reaction kettle to drop to room temperature, transfer the reaction solution to a rotary evaporator, raise the temperature of the rotary evaporator to 60 - 80 °C, and distill under reduced pressure until no liquid is collected, to obtain the modified chain extender precursor;

[0032] Further, the dosage ratio of the modified chain extender precursor, N,N-dimethylformamide, deionized water and the composite copper framework is 12 - 15 g : 40 - 60 mL : 10 - 20 mL : 2 - 3 g. The post-treatment includes: after the reaction is completed, wait for the temperature of the reaction kettle to drop to room temperature, transfer the reaction solution to a rotary evaporator, raise the temperature of the rotary evaporator to 60 - 80 °C, and distill under reduced pressure until no liquid is collected, to obtain the modified chain extender.

[0033] Further, the preparation method of the composite copper framework includes the following steps:

[0034] C1. Add the trimesic acid dispersion liquid and copper nitrate trihydrate dispersion liquid into an ultrasonic instrument, and ultrasonically treat at room temperature for 20 - 30 min to obtain a mixed liquid;

[0035] C2. Add the mixed liquid into a polytetrafluoroethylene reaction kettle, seal it, and then transfer the reaction kettle to an oven at a temperature of 110 - 120 °C for hydrothermal reaction for 12 h, and perform post-treatment to obtain an organic copper framework;

[0036] C3. Add anhydrous zinc acetate, titanium tetrachloride, the organic copper framework and a mixed solvent into an ultrasonic instrument, ultrasonically treat at room temperature for 20 - 30 min, and during the ultrasonic treatment, dropwise add dopamine hydrochloride and 3-(methacryloyloxy)propyltrimethoxysilane into the ultrasonic instrument. After the ultrasonic treatment is completed, adjust the pH of the reaction solution to 8 - 9 with saturated sodium hydroxide aqueous solution, and add the reaction solution into a polytetrafluoroethylene reaction kettle, seal it, and then transfer the reaction kettle to an oven at a temperature of 120 - 130 °C for hydrothermal reaction for 24 h, and perform post-treatment to obtain the composite copper framework.

[0037] The reaction principle for preparing the composite copper framework is as follows: Trimesic acid molecules contain three carboxyl groups. Under hydrothermal conditions, some of them dissociate into carboxylate ions. These carboxylate ions act as ligands and coordinate with copper ions released after copper nitrate dissolves in water to form a metal-organic framework structure, obtaining an organic copper framework. In an alkaline hydrothermal environment, zinc acetate anhydrous dissociates to generate zinc ions, which react with hydroxyl groups to form zinc hydroxide precipitate. Subsequently, it is transformed into zinc oxide nanoparticles under high temperature and pressure and adheres to the surface through van der Waals forces or coordination. Titanium tetrachloride hydrolyzes in water to form titanium dioxide, and the alkaline condition promotes its condensation into titanium dioxide nanoparticles, which are anchored by the coordination of carboxyl groups or copper ions on the surface of the organic copper framework. Moreover, dopamine hydrochloride dissociates into dopamine under alkaline conditions, and its catechol groups are easily oxidized to form polydopamine, which is firmly adsorbed on the surface of the organic copper framework through hydrogen bonds, π-π stacking, and the coordination of copper ions. At the same time, the adhesiveness of polydopamine enhances the binding stability between the oxidant and titanium dioxide, and carbon-carbon double bonds are modified on the surface of the organic copper framework through siloxane hydrolysis, finally obtaining the composite copper framework.

[0038] Furthermore, in step C1, the dosage ratio of the trimesic acid dispersion liquid to the copper nitrate trihydrate dispersion liquid is 1 mL:1 mL. Among them, the trimesic acid dispersion liquid is obtained by mixing trimesic acid and absolute ethanol in a dosage ratio of 2.0 - 2.4 g:25 mL, and the copper nitrate trihydrate dispersion liquid is obtained by mixing copper nitrate trihydrate and deionized water in a dosage ratio of 2.5 - 2.7 g:25 mL.

[0039] Furthermore, in step C2, the post-treatment is as follows: After the reaction is completed, the reaction solution is filtered by suction to collect the precipitate. After washing the precipitate 3 - 5 times with absolute ethanol and deionized water, the precipitate is transferred to a vacuum drying oven at a temperature of 60 - 80 °C and vacuum dried to constant weight to obtain the organic copper framework.

[0040] Furthermore, in step C3, the ultrasonic frequency of the ultrasonic instrument is 20 - 30 kHz, and the dosage ratio of zinc acetate anhydrous, titanium tetrachloride, organic copper framework, mixed solvent, dopamine hydrochloride, and 3-(methacryloyloxy)propyltrimethoxysilane is 3.6 - 3.8 g:1.9 - 2.0 g:16 - 18 g:100 - 120 mL:0.1 - 0.2 g:1 - 2 g. Among them, the mixed solvent is obtained by mixing absolute ethanol and deionized water in a dosage ratio of 1 mL:1 mL. The post-treatment is as follows: After the reaction is completed, the reaction solution is filtered by suction to collect the precipitate. After washing the precipitate 3 - 5 times with absolute ethanol and deionized water, the precipitate is transferred to a vacuum drying oven at a temperature of 60 - 80 °C and vacuum dried to constant weight to obtain the composite copper framework.

[0041] The present invention also provides a method for preparing a flame-retardant and aging-resistant cable for solar power generation, comprising the following steps:

[0042] S1. Stranding several copper wires to obtain a conductor layer;

[0043] S2. Adding a composite polyvinyl fluoride material into a twin-screw extruder, melting and extruding it to coat the surface of the conductor layer, and naturally curing to obtain an insulating layer;

[0044] S3. Wrapping a copper tape around the surface of the insulating layer to obtain a shielding layer;

[0045] S4. Adding a composite polyvinylidene chloride material into a twin-screw extruder, melting and extruding it to coat the surface of the shielding layer, and naturally curing to obtain an outer sheath layer.

[0046] Further, in step S1, the diameter of the copper wires used is 0.5 mm;

[0047] Further, in step S2, the composite polyvinyl fluoride material comprises the following raw materials by weight: 60 - 80 parts of modified polyvinylidene chloride, 10 - 15 parts of plasticizer, 2 - 5 parts of stabilizer, and 1 - 2 parts of lubricant. Among them, the plasticizer is phthalic acid diester; the stabilizer is one or two of tribasic lead sulfate and dibutyltin dilaurate; the lubricant is one or two of calcium stearate and zinc stearate.

[0048] Further, in step S2, the temperatures of the eight temperature zones of the twin-screw extruder from the feed port to the discharge port are 180 °C, 185 °C, 185 °C, 190 °C, 195 °C, 200 °C, 210 °C, 210 °C in sequence. The main machine speed of the twin-screw extruder is 80 - 120 rpm, the pressure is 100 - 150 bar. Melting and extruding it to the surface of the conductor layer, and naturally curing to obtain an insulating layer, with the thickness controlled to be 1.0 - 1.2 mm;

[0049] Further, in step S2, the thickness of the copper tape is 0.08 - 0.10 mm, and the number of wrapping layers is 1 layer;

[0050] Further, in step S4, the temperatures of the eight temperature zones of the twin-screw extruder from the feed port to the discharge port are 180 °C, 185 °C, 185 °C, 190 °C, 195 °C, 200 °C, 210 °C, 210 °C in sequence. The main machine speed of the twin-screw extruder is 80 - 120 rpm, the pressure is 100 - 150 bar. Melting and extruding it to the surface of the shielding layer, and naturally curing to obtain an outer sheath layer, with the thickness controlled to be 1.5 - 1.6 mm.

[0051] The present invention has the following beneficial effects:

[0052] 1. The titanium dioxide modified on the surface of the composite copper frame in the present invention has high hardness and chemical stability, enhances the mechanical strength of the polymer matrix, reduces surface damage during wear, and its wide-bandgap semiconductor property absorbs ultraviolet energy and converts it into heat energy dissipation, inhibiting photo-oxidative degradation. The benzotriazole structure in the modified chain extender efficiently absorbs ultraviolet light through the conjugated system, and the excited-state energy is dissipated through molecular vibration, preventing the generation of free radicals, significantly improving the anti-ultraviolet aging performance. Moreover, the siloxane long chain introduced by methylphenylvinylsilicone oil has a low surface energy and high flexibility, enhancing the anti-ultraviolet stability of the molecular chain, reducing photo-initiated chain scission. The triazine group and carbon-nitrogen double bond are introduced into the polymer chain through double-bond polymerization, increasing the crosslinking density and chain rigidity, and improving the resistance to chain segment slippage. The zinc oxide component further enhances the hardness of the matrix and the wear resistance. The siloxane chain segment, modified anti-ultraviolet agent, and titanium dioxide synergistically inhibit ultraviolet degradation, maintaining the mechanical properties. The hard filler effect of titanium dioxide and zinc oxide and the molecular chain strengthening jointly improve the surface anti-wear ability, prolonging the service life of the cable in harsh environments and meeting the requirements of solar power generation.

[0053] 2. The titanium dioxide and zinc oxide modified on the surface of the composite copper frame in the present invention have high thermal stability, absorb combustion heat and form a heat-insulating layer, slowing down the thermal decomposition rate and inhibiting flame propagation. At the same time, the methylphenylvinylsilicone oil in the modified chain extender introduces siloxane chain segments, which generate a stable siloxane char layer during combustion, blocking the transfer of oxygen and heat, reducing the release of combustible gases. The triazine group is incorporated into the polymer chain through double-bond polymerization, and its nitrogen-containing structure releases non-combustible gases such as nitrogen at high temperatures, diluting the oxygen concentration and interrupting the combustion chain reaction. The benzotriazole structure in the modified anti-ultraviolet agent enhances the thermal stability of the molecular chain, reducing the combustible volatiles generated by high-temperature decomposition. Moreover, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide introduces a phosphorus-containing structure through phosphorus-hydrogen addition, forming phosphoric acid or polyphosphoric acid during combustion, promoting carbonization and generating a dense char layer, isolating oxygen and inhibiting the flame. By utilizing the synergistic effect among the components, through forming a physical barrier, releasing non-combustible gases, and promoting carbonization, the flame retardancy of the cable is significantly improved, ensuring safety and durability in the solar power generation system.

[0054] 3. The composite copper frame prepared by the present invention has 1,3,5-benzenetricarboxylic acid copper as the core. Its metal copper ions have good electrical conductivity, can effectively shield external electromagnetic waves, form the Faraday cage effect, reduce the influence of electromagnetic interference on the cable transmission signal. At the same time, the surface-modified titanium dioxide and zinc oxide, as high dielectric constant materials, further enhance the electromagnetic wave absorption and scattering ability of the composite copper frame, weaken the electromagnetic wave penetration. And the methylphenylvinyl silicone oil in the chain extender introduces siloxane segments, and its low dielectric loss characteristic reduces the energy loss of the electrical signal in the polymer matrix, maintaining signal integrity. The triazine groups and carbon-nitrogen double bonds form a highly crosslinked polymer network through double bond polymerization, enhancing the overall structural stability of the material, thereby reducing the molecular polarization effect under the action of the electromagnetic field and reducing the dielectric loss. The benzotriazole structure in the modified ultraviolet absorber stabilizes the electron cloud distribution through the conjugated system, reduces the electron migration caused by the electromagnetic field. Utilizing the synergistic effect between components, through conductive shielding, electromagnetic wave absorption and low dielectric loss, the electromagnetic interference resistance performance of the cable is significantly improved, ensuring the stability and reliability of signal transmission in the solar power generation system. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0056] Figure 1 It is a schematic structural diagram of the cable for solar power generation prepared by the present invention.

[0057] In the figure: 1. Conductor layer; 2. Insulating layer; 3. Shielding layer; 4. Outer sheath layer. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0058] The following will clearly and completely describe the technical solutions of the present invention in combination with the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0059] The methylphenylvinyl silicone oil used in the present invention is purchased from Anhui Mingyi Silicone Oil Co., Ltd., and the product number is MY252;

[0060] The polyvinyl fluoride used in the present invention is purchased from Shanghai Bevanta Biotechnology Co., Ltd., and the product number is BK-12341;

[0061] The calcium stearate used in the present invention was purchased from Tianjin Siyanshi Biochemical Technology Co., Ltd., and the product number is C-08652+500g.

[0062] Example 1

[0063] This example provides a preparation method of a composite copper frame for preparing a flame-retardant and aging-resistant cable for solar power generation, including the following steps:

[0064] Step ①, prepare the mixed solution

[0065] Weigh: 20.0 g of trimesic acid and 250.0 mL of absolute ethanol are mixed to obtain a trimesic acid dispersion;

[0066] Weigh: 25.0 g of copper nitrate trihydrate and 250.0 mL of deionized water are mixed to obtain a copper nitrate trihydrate dispersion;

[0067] Weigh: 240.0 mL of the trimesic acid dispersion and 240.0 mL of the copper nitrate trihydrate dispersion are added to an ultrasonic instrument, and after ultrasonic treatment at room temperature for 20 min, a mixed solution is obtained.

[0068] Step ②, prepare the organic copper frame

[0069] Weigh: 450.0 mL of the mixed solution is added to a polytetrafluoroethylene reaction kettle, sealed, and then the reaction kettle is placed in an oven at a temperature of 100 °C for hydrothermal reaction for 12 h. After the reaction is completed, the reaction solution is filtered by suction to collect the precipitate. After washing the precipitate 3 times with absolute ethanol and deionized water, the precipitate is transferred to a vacuum drying oven at a temperature of 60 °C and vacuum dried to constant weight to obtain the organic copper frame.

[0070] Step ③, prepare the composite copper frame

[0071] Weigh: 60.0 mL of absolute ethanol and 60.0 mL of deionized water are mixed to obtain a mixed solvent;

[0072] Weigh: 3.6 g of zinc acetate anhydrous, 1.9 g of titanium tetrachloride, 16.0 g of the organic copper frame and 100.0 mL of the mixed solvent are added to an ultrasonic instrument, and ultrasonic treatment is carried out at room temperature for 20 min. During the ultrasonic process, 0.1 g of dopamine hydrochloride and 1.0 g of 3-(methacryloyloxy)propyltrimethoxysilane are added dropwise to the ultrasonic instrument. After the ultrasonic treatment is completed, the pH of the reaction solution is adjusted to 8 with a saturated sodium hydroxide aqueous solution, and the reaction solution is added to a polytetrafluoroethylene reaction kettle, sealed, and then the reaction kettle is transferred to an oven at a temperature of 120 °C for hydrothermal reaction for 24 h. After the reaction is completed, the reaction solution is filtered by suction to collect the precipitate. After washing the precipitate 3 times with absolute ethanol and deionized water, the precipitate is transferred to a vacuum drying oven at a temperature of 60 °C and vacuum dried to constant weight to obtain the composite copper frame.

[0073] Example 2

[0074] This embodiment provides a preparation method of a composite copper frame for a flame-retardant and aging-resistant cable used in solar power generation, including the following steps:

[0075] Step ①, preparing a mixed solution

[0076] Weigh: 24.0 g of trimellitic acid and 250.0 mL of absolute ethanol are mixed to obtain a trimellitic acid dispersion;

[0077] Weigh: 27.0 g of copper nitrate trihydrate and 250.0 mL of deionized water are mixed to obtain a copper nitrate trihydrate dispersion;

[0078] Weigh: 480.0 mL of the trimellitic acid dispersion and the copper nitrate trihydrate dispersion are added to an ultrasonic instrument. After ultrasonic treatment at room temperature for 30 min, a mixed solution is obtained.

[0079] Step ②, preparing an organic copper frame

[0080] Weigh: 450.0 mL of the mixed solution is added to a polytetrafluoroethylene reaction kettle. After sealing, the reaction kettle is placed in an oven at a temperature of 120 °C for hydrothermal reaction for 12 h. After the reaction is completed, the reaction solution is filtered by suction to collect the precipitate. After washing the precipitate 5 times with absolute ethanol and deionized water, the precipitate is transferred to a vacuum drying oven at a temperature of 80 °C for vacuum drying to constant weight to obtain an organic copper frame.

[0081] Step ③, preparing a composite copper frame

[0082] Weigh: 60.0 mL of absolute ethanol and 60.0 mL of deionized water are mixed to obtain a mixed solvent;

[0083] Weigh: 3.8 g of zinc acetate anhydrous, 2.0 g of titanium tetrachloride, 18.0 g of the organic copper frame and 100.0 mL of the mixed solvent are added to an ultrasonic instrument. Ultrasonic treatment is carried out at room temperature for 30 min. During the ultrasonic process, 0.2 g of dopamine hydrochloride and 2.0 g of 3-(methacryloyloxy)propyltrimethoxysilane are added dropwise to the ultrasonic instrument. After ultrasonic treatment is completed, the pH of the reaction solution is adjusted to 9 with a saturated sodium hydroxide aqueous solution, and the reaction solution is added to a polytetrafluoroethylene reaction kettle. After sealing, the reaction kettle is transferred to an oven at a temperature of 130 °C for hydrothermal reaction for 24 h. After the reaction is completed, the reaction solution is filtered by suction to collect the precipitate. After washing the precipitate 5 times with absolute ethanol and deionized water, the precipitate is transferred to a vacuum drying oven at a temperature of 80 °C for vacuum drying to constant weight to obtain a composite copper frame.

[0084] Example 3

[0085] This embodiment provides a preparation method of a composite copper frame for a flame-retardant and aging-resistant cable used in solar power generation, including the following steps:

[0086] Step ①, preparing a mixed solution

[0087] Weigh: 21.0 g of trimesic acid and 250.0 mL of absolute ethanol are mixed to obtain a trimesic acid dispersion;

[0088] Weigh: 26.0 g of copper nitrate trihydrate and 250.0 mL of deionized water are mixed to obtain a copper nitrate trihydrate dispersion;

[0089] Weigh: 480.0 mL of the trimesic acid dispersion and the copper nitrate trihydrate dispersion are added to an ultrasonic instrument. After ultrasonic treatment at room temperature for 30 min, a mixed solution is obtained.

[0090] Step ②, Preparation of organic copper framework

[0091] Weigh: 450.0 mL of the mixed solution is added to a polytetrafluoroethylene reaction kettle. After sealing, the reaction kettle is placed in an oven at a temperature of 120 °C for hydrothermal reaction for 12 h. After the reaction is completed, the reaction solution is filtered by suction to collect the precipitate. After washing the precipitate 4 times with absolute ethanol and deionized water, the precipitate is transferred to a vacuum drying oven at a temperature of 70 °C for vacuum drying to constant weight to obtain an organic copper framework.

[0092] Step ③, Preparation of composite copper framework

[0093] Weigh: 60.0 mL of absolute ethanol and 60.0 mL of deionized water are mixed to obtain a mixed solvent;

[0094] Weigh: 3.7 g of anhydrous zinc acetate, 2.0 g of titanium tetrachloride, 18.0 g of the organic copper framework and 100.0 mL of the mixed solvent are added to an ultrasonic instrument. Ultrasonic at room temperature for 25 min. During the ultrasonic process, 0.2 g of dopamine hydrochloride and 2.0 g of 3-(methacryloyloxy)propyltrimethoxysilane are added dropwise to the ultrasonic instrument. After ultrasonic treatment is completed, the pH of the reaction solution is adjusted to 9 with saturated sodium hydroxide aqueous solution, and the reaction solution is added to a polytetrafluoroethylene reaction kettle. After sealing, the reaction kettle is transferred to an oven at a temperature of 130 °C for hydrothermal reaction for 24 h. After the reaction is completed, the reaction solution is filtered by suction to collect the precipitate. After washing the precipitate 4 times with absolute ethanol and deionized water, the precipitate is transferred to a vacuum drying oven at a temperature of 70 °C for vacuum drying to constant weight to obtain a composite copper framework.

[0095] Example 4

[0096] This example provides a preparation method of a modified chain extender for preparing a flame-retardant and aging-resistant cable for solar power generation, including the following steps:

[0097] Step Ⅰ, Preparation of modified ultraviolet absorber

[0098] Weigh: 60.0 g of 4-(2H-benzotriazol-2-yl)-1,3-benzenediol and 360.0 mL of N,N-dimethylformamide are added to a low-temperature reaction kettle. After purging with nitrogen, the temperature of the reaction kettle is lowered to 5 °C, and 24.0 g of acryloyl chloride is added dropwise to the reaction kettle. The reaction is carried out at a constant temperature for 6 h. After the reaction is completed, an equal volume of saturated sodium bicarbonate solution is added to the reaction solution. After stirring for 5 min, when the solution is stratified, the upper layer liquid is taken. Then, an equal volume of absolute ethanol is added to the upper layer liquid, and the solution is transferred to a rotary evaporator. The temperature of the rotary evaporator is raised to 60 °C, and the solution is distilled under reduced pressure until no more liquid is collected, obtaining a modified ultraviolet absorber.

[0099] Step II: Preparation of the precursor of the modified chain extender

[0100] Weigh: 80.0 g of the modified ultraviolet absorber, 50.0 g of methylphenylvinyl silicone oil, and 800.0 mL of N,N-dimethylformamide are added to a reaction kettle. After the temperature of the reaction kettle is raised to 60 °C, 10.0 g of azobisisobutyronitrile is added to the reaction kettle. After reacting at a constant temperature for 1 h, 10.0 g of 11-mercaptoundecyltrimethoxysilane is added to the reaction kettle, and the reaction is carried out at a constant temperature for 20 min. After the reaction is completed, when the temperature of the reaction kettle is lowered to room temperature, the reaction solution is transferred to a rotary evaporator. The temperature of the rotary evaporator is raised to 60 °C, and the solution is distilled under reduced pressure until no more liquid is collected, obtaining the precursor of the modified chain extender.

[0101] Step III: Preparation of the modified chain extender

[0102] Weigh: 120.0 g of the precursor of the modified chain extender, 400.0 mL of N,N-dimethylformamide, and 100.0 mL of deionized water are added to a reaction kettle and stirred. The temperature of the reaction kettle is raised to 60 °C, and the pH of the reaction system is adjusted to 8 using a saturated sodium hydroxide aqueous solution. 20.0 g of the composite copper framework prepared in Example 1 is added to the reaction kettle, and the mixture is stirred at a constant temperature for 40 min. After the reaction is completed, when the temperature of the reaction kettle is lowered to room temperature, the reaction solution is transferred to a rotary evaporator. The temperature of the rotary evaporator is raised to 60 °C, and the solution is distilled under reduced pressure until no more liquid is collected, obtaining the modified chain extender.

[0103] Example 5

[0104] This example provides a preparation method of a modified chain extender for a flame-retardant and aging-resistant cable used in solar power generation, including the following steps:

[0105] Step I: Preparation of the modified ultraviolet absorber

[0106] Weigh: 75.0 g of 4-(2H-benzotriazol-2-yl)-1,3-benzenediol and 400.0 mL of N,N-dimethylformamide are added to a low-temperature reaction kettle. After purging with nitrogen, the temperature of the reaction kettle is lowered to 0 °C, and 30.0 g of acryloyl chloride is added dropwise to the reaction kettle. After maintaining the temperature for 8 h, after the reaction is completed, an equal volume of saturated sodium bicarbonate solution is added to the reaction solution. After stirring for 6 min, when the solution is layered, the upper layer liquid is taken. Then, an equal volume of absolute ethanol is added to the upper layer liquid, and the solution is transferred to a rotary evaporator. The temperature of the rotary evaporator is raised to 80 °C, and under reduced pressure distillation until no liquid is collected, a modified anti-ultraviolet agent is obtained.

[0107] Step II: Preparation of modified chain extender precursor

[0108] Weigh: 100.0 g of modified anti-ultraviolet agent, 60.0 g of methylphenylvinylsilicone oil and 900.0 mL of N,N-dimethylformamide are added to a reaction kettle. After the temperature of the reaction kettle is raised to 80 °C, 20.0 g of azobisisobutyronitrile is added to the reaction kettle. After maintaining the temperature for 2 h, 20.0 g of 11-mercaptoundecyltrimethoxysilane is added to the reaction kettle. After maintaining the temperature for 30 min, after the reaction is completed, when the temperature of the reaction kettle is lowered to room temperature, the reaction solution is transferred to a rotary evaporator. The temperature of the rotary evaporator is raised to 80 °C, and under reduced pressure distillation until no liquid is collected, a modified chain extender precursor is obtained.

[0109] Step III: Preparation of modified chain extender

[0110] Weigh: 150.0 g of modified chain extender precursor, 600.0 mL of N,N-dimethylformamide and 200.0 mL of deionized water are added to a reaction kettle and stirred. The temperature of the reaction kettle is raised to 80 °C, and the pH of the reaction system is adjusted to 10 using a saturated sodium hydroxide aqueous solution. 24.0 g of the composite copper framework prepared in Example 2 is added to the reaction kettle, and the mixture is stirred for 60 min. After the reaction is completed, when the temperature of the reaction kettle is lowered to room temperature, the reaction solution is transferred to a rotary evaporator. The temperature of the rotary evaporator is raised to 80 °C, and under reduced pressure distillation until no liquid is collected, a modified chain extender is obtained.

[0111] Example 6

[0112] This example provides a preparation method of a modified chain extender for a flame-retardant and aging-resistant cable used in solar power generation, including the following steps:

[0113] Step I: Preparation of modified anti-ultraviolet agent

[0114] Weigh: 67.0 g of 4-(2H-benzotriazol-2-yl)-1,3-benzenediol and 360.0 mL of N,N-dimethylformamide and add them to a low-temperature reaction kettle. After introducing nitrogen for protection, the temperature of the reaction kettle is reduced to 3 °C, and 27.0 g of acryloyl chloride is added dropwise to the reaction kettle. Keep the temperature for reaction for 8 h. After the reaction is completed, add an equal volume of saturated sodium bicarbonate solution to the reaction solution, stir for 6 min, and after the solution is layered, take the upper liquid. Then add an equal volume of anhydrous ethanol to the upper liquid, transfer the solution to a rotary evaporator, raise the temperature of the rotary evaporator to 80 °C, and distill under reduced pressure until no liquid is collected, to obtain a modified chain extender precursor.

[0115] Step II: Preparation of modified chain extender precursor

[0116] Weigh: 90.0 g of modified anti-ultraviolet agent, 54.0 g of methylphenylvinyl silicone oil and 840.0 mL of N,N-dimethylformamide and add them to a reaction kettle. After the temperature of the reaction kettle is raised to 70 °C, 16.0 g of azobisisobutyronitrile is added to the reaction kettle. Keep the temperature for reaction for 2 h, then add 16.0 g of 11-mercaptoundecyltrimethoxysilane to the reaction kettle, and keep the temperature for reaction for 24 min. After the reaction is completed, wait for the temperature of the reaction kettle to drop to room temperature, transfer the reaction solution to a rotary evaporator, raise the temperature of the rotary evaporator to 70 °C, and distill under reduced pressure until no liquid is collected, to obtain a modified chain extender precursor.

[0117] Step III: Preparation of modified chain extender

[0118] Weigh: 136.0 g of modified chain extender precursor, 500.0 mL of N,N-dimethylformamide and 160.0 mL of deionized water and add them to a reaction kettle for stirring. Raise the temperature of the reaction kettle to 70 °C, and use a saturated sodium hydroxide aqueous solution to adjust the pH of the reaction system to 9. Add 21.0 g of the composite copper framework prepared in Example 3 to the reaction kettle, and stir for 50 min. After the reaction is completed, wait for the temperature of the reaction kettle to drop to room temperature, transfer the reaction solution to a rotary evaporator, raise the temperature of the rotary evaporator to 70 °C, and distill under reduced pressure until no liquid is collected, to obtain a modified chain extender.

[0119] Example 7

[0120] This example provides a preparation method of modified polyvinylidene chloride for a flame-retardant and aging-resistant cable used in solar power generation, including the following steps:

[0121] Step (i): Weigh chain-extended polyvinylidene chloride

[0122] Weigh: 45.0 g of trans-1,2-dichloroethylene, 36.0 g of 2-vinyl-4,6-diamino-1,3,5-triazine, 45.0 g of 4-trimethylsilyl-N-tert-butyl-2-butenimine, 10.0 g of azobisisobutyronitrile, 160.0 mL of polytetrahydrofuran and 300.0 mL of N,N-dimethylacetamide were added to a high-pressure reactor. The temperature of the reactor was raised to 60 °C. After holding the reaction for 1 h, 20.0 g of the modified chain extender prepared in Example 4 was added to the reactor, and the reaction was continued for 30 min while maintaining the temperature. After the reaction was completed, when the temperature of the reactor was lowered to room temperature, the reaction solution was transferred to a rotary evaporator. The temperature of the rotary evaporator was raised to 60 °C, and the solution was distilled under reduced pressure until no more liquid was collected, obtaining chain-extended polyvinylidene chloride.

[0123] Step (ii), preparing modified polyvinylidene chloride

[0124] Weigh: 130.0 g of chain-extended polyvinylidene chloride, 45.0 g of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10.0 g of aluminum chloride and 800.0 mL of N,N-dimethylacetamide were added to a reactor. The temperature of the reactor was raised to 40 °C, and the reaction was held for 1 h. After the reaction was completed, when the temperature of the reactor was lowered to room temperature, the reaction solution was transferred to a rotary evaporator. The temperature of the rotary evaporator was raised to 60 °C, and the solution was distilled under reduced pressure until no more liquid was collected, obtaining modified polyvinylidene chloride.

[0125] Example 8

[0126] This example provides a method for preparing modified polyvinylidene chloride for use in a flame-retardant and aging-resistant cable for solar power generation, including the following steps:

[0127] Step (i), weighing chain-extended polyvinylidene chloride

[0128] Weigh: 55.0 g of trans-1,2-dichloroethylene, 44.0 g of 2-vinyl-4,6-diamino-1,3,5-triazine, 55.0 g of 4-trimethylsilyl-N-tert-butyl-2-butenimine, 20.0 g of azobisisobutyronitrile, 200.0 mL of polytetrahydrofuran and 360.0 mL of N,N-dimethylacetamide were added to a high-pressure reactor. The temperature of the reactor was raised to 80 °C. After holding the reaction for 2 h, 30.0 g of the modified chain extender prepared in Example 5 was added to the reactor, and the reaction was continued for 40 min while maintaining the temperature. After the reaction was completed, when the temperature of the reactor was lowered to room temperature, the reaction solution was transferred to a rotary evaporator. The temperature of the rotary evaporator was raised to 80 °C, and the solution was distilled under reduced pressure until no more liquid was collected, obtaining chain-extended polyvinylidene chloride.

[0129] Step (ii), preparing modified polyvinylidene chloride

[0130] Weigh: 150.0 g of chain-extended polyvinylidene chloride, 55.0 g of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 20.0 g of aluminum chloride and 900.0 mL of N,N-dimethylacetamide were added to a reaction kettle. The temperature of the reaction kettle was raised to 60 °C and kept for reaction for 2 h. After the reaction was completed, when the temperature of the reaction kettle dropped to room temperature, the reaction solution was transferred to a rotary evaporator. The temperature of the rotary evaporator was raised to 80 °C, and vacuum distillation was carried out until no liquid was collected, and then modified polyvinylidene chloride was obtained.

[0131] Example 9

[0132] This example provides a preparation method of modified polyvinylidene chloride for preparing a flame-retardant and aging-resistant cable for solar power generation, including the following steps:

[0133] Step (i), weigh chain-extended polyvinylidene chloride

[0134] Weigh: 50.0 g of trans-1,2-dichloroethylene, 40.0 g of 2-vinyl-4,6-diamino-1,3,5-triazine, 50.0 g of 4-trimethylsilyl-N-tert-butyl-2-buteneimine, 16.0 g of azobisisobutyronitrile, 180.0 mL of polytetrahydrofuran and 320.0 mL of N,N-dimethylacetamide were added to a high-pressure reaction kettle. The temperature of the reaction kettle was raised to 70 °C and kept for reaction for 2 h. Then, 24.0 g of the modified chain extender prepared in Example 6 was added to the reaction kettle, and the reaction was kept for 36 min. After the reaction was completed, when the temperature of the reaction kettle dropped to room temperature, the reaction solution was transferred to a rotary evaporator. The temperature of the rotary evaporator was raised to 70 °C, and vacuum distillation was carried out until no liquid was collected, and then chain-extended polyvinylidene chloride was obtained.

[0135] Step (ii), prepare modified polyvinylidene chloride

[0136] Weigh: 140.0 g of chain-extended polyvinylidene chloride, 50.0 g of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 16.0 g of aluminum chloride and 880.0 mL of N,N-dimethylacetamide were added to a reaction kettle. The temperature of the reaction kettle was raised to 50 °C and kept for reaction for 2 h. After the reaction was completed, when the temperature of the reaction kettle dropped to room temperature, the reaction solution was transferred to a rotary evaporator. The temperature of the rotary evaporator was raised to 70 °C, and vacuum distillation was carried out until no liquid was collected, and then modified polyvinylidene chloride was obtained.

[0137] Example 10

[0138] This example provides a preparation method of a flame-retardant and aging-resistant cable for solar power generation, including the following steps:

[0139] Step one, prepare a conductor layer

[0140] Three copper wires with a diameter of 0.5 mm were stranded to obtain conductor layer 1.

[0141] Step 2: Prepare the insulating layer

[0142] Weigh: 60 parts of modified polyvinylidene chloride, 10 parts of dibutyl phthalate, 2 parts of dibutyltin dilaurate and 1 part of calcium stearate and add them to a twin-screw extruder. The temperatures of the eight temperature zones of the twin-screw extruder from the feed inlet to the discharge outlet are 180°C, 185°C, 185°C, 190°C, 195°C, 200°C, 210°C, 210°C in sequence. The main machine speed of the twin-screw extruder is 80 rpm, the pressure is 100 bar, and it is melt-extruded onto the surface of the conductor layer and naturally cured to obtain the insulating layer 2, and the thickness of the insulating layer is controlled to be 1.0 mm.

[0143] Step 3: Prepare the shielding layer

[0144] Wind a copper tape with a thickness of 0.08 mm around the surface of the insulating layer for one layer to obtain the shielding layer 3.

[0145] Step 4: Prepare the cable for solar power generation

[0146] Weigh: 70 parts of the modified polyvinylidene chloride prepared in Example 7, 15 parts of dibutyl phthalate, 2 parts of dibutyltin dilaurate, 1 part of calcium stearate and 1 part of 2,6-di-tert-butyl-p-cresol and add them to a twin-screw extruder. The temperatures of the eight temperature zones of the twin-screw extruder from the feed inlet to the discharge outlet are 180°C, 185°C, 185°C, 190°C, 195°C, 200°C, 210°C, 210°C in sequence. The main machine speed of the twin-screw extruder is 80 rpm, the pressure is 100 bar, and it is melt-extruded onto the surface of the shielding layer and naturally cured to obtain the outer sheath layer 4, and the thickness is controlled to be 1.5 mm, thus obtaining the cable for solar power generation.

[0147] Example 11

[0148] This example provides a method for preparing a flame-retardant and aging-resistant cable for solar power generation, including the following steps:

[0149] Step 1: Prepare the conductor layer

[0150] Strand 3 copper wires with a diameter of 0.5 mm to obtain the conductor layer 1.

[0151] Step 2: Prepare the insulating layer

[0152] Weigh: Add 80 parts of modified polyvinylidene chloride, 15 parts of dibutyl phthalate, 5 parts of dibutyltin dilaurate, and 2 parts of calcium stearate into a twin-screw extruder. The temperatures of the eight temperature zones of the twin-screw extruder from the feed inlet to the discharge outlet are 180 °C, 185 °C, 185 °C, 190 °C, 195 °C, 200 °C, 210 °C, and 210 °C in sequence. The main machine speed of the twin-screw extruder is 120 rpm, and the pressure is 150 bar. Melt and extrude it onto the surface of the conductor layer, and naturally cure to obtain the insulating layer 2. The thickness of the insulating layer is controlled to be 1.2 mm.

[0153] Step Three: Prepare the shielding layer

[0154] Wind a copper tape with a thickness of 0.10 mm around the surface of the insulating layer for one layer to obtain the shielding layer 3.

[0155] Step Four: Prepare the cable for solar power generation

[0156] Weigh: Add 80 parts of the modified polyvinylidene chloride prepared in Example 8, 20 parts of dibutyl phthalate, 5 parts of dibutyltin dilaurate, 2 parts of calcium stearate, and 2 parts of 2,6-di-tert-butyl-p-cresol into a twin-screw extruder. The temperatures of the eight temperature zones of the twin-screw extruder from the feed inlet to the discharge outlet are 180 °C, 185 °C, 185 °C, 190 °C, 195 °C, 200 °C, 210 °C, and 210 °C in sequence. The main machine speed of the twin-screw extruder is 120 rpm, and the pressure is 150 bar. Melt and extrude it onto the surface of the shielding layer, and naturally cure to obtain the outer sheath layer 4 with a thickness controlled to be 1.6 mm, thus obtaining the cable for solar power generation.

[0157] Example 12

[0158] This example provides a method for preparing a flame-retardant and aging-resistant cable for solar power generation, including the following steps:

[0159] Step One: Prepare the conductor layer

[0160] Strand 3 copper wires with a diameter of 0.5 mm to obtain the conductor layer 1.

[0161] Step Two: Prepare the insulating layer

[0162] Weigh: Add 72 parts of modified polyvinylidene chloride, 12 parts of dibutyl phthalate, 3 parts of dibutyltin dilaurate, and 2 parts of calcium stearate into a twin-screw extruder. The temperatures of the eight temperature zones of the twin-screw extruder from the feed inlet to the discharge outlet are 180 °C, 185 °C, 185 °C, 190 °C, 195 °C, 200 °C, 210 °C, and 210 °C in sequence. The main machine speed of the twin-screw extruder is 100 rpm, and the pressure is 120 bar. Melt and extrude it onto the surface of the conductor layer, and naturally cure to obtain the insulating layer 2. The thickness of the insulating layer is controlled to be 1.0 mm.

[0163] Step 3: Prepare the shielding layer

[0164] Wrap a copper strip with a thickness of 0.09 mm around the surface of the insulating layer for one layer to obtain the shielding layer 3.

[0165] Step 4: Prepare the cable for solar power generation

[0166] Weigh: 72 parts of the modified polyvinylidene chloride prepared in Example 9, 18 parts of dibutyl phthalate, 3 parts of dibutyltin dilaurate, 2 parts of calcium stearate, and 2 parts of 2,6-di-tert-butyl-p-cresol and add them to a twin-screw extruder. The temperatures of the eight temperature zones of the twin-screw extruder from the feed port to the discharge port are 180 °C, 185 °C, 185 °C, 190 °C, 195 °C, 200 °C, 210 °C, and 210 °C in sequence. The main machine speed of the twin-screw extruder is 100 rpm, the pressure is 120 bar, and it is melt-extruded onto the surface of the shielding layer and naturally cured to obtain the outer sheath layer 4 with a thickness controlled to be 1.6 mm, thus obtaining the cable for solar power generation.

[0167] Comparative Example 1

[0168] The difference between this comparative example and Example 12 is that in the modified chain extender used in the preparation of the modified polyvinylidene chloride used in Step 4, the composite copper frame used is prepared without Step ③.

[0169] Comparative Example 2

[0170] The difference between this comparative example and Example 12 is that in the modified chain extender used in the preparation of the modified polyvinylidene chloride used in Step 4, the use of the composite copper frame is cancelled during the preparation.

[0171] Comparative Example 3

[0172] The difference between this comparative example and Example 12 is that the use of the composite chain extender is cancelled during the preparation of the modified polyvinylidene chloride used in Step 4.

[0173] Performance test:

[0174] Refer to the standard GB / T 9867-2008 "Determination of Abrasion Resistance of Vulcanized Rubber or Thermoplastic Rubber (Rotating Drum Abrasion Machine Method)" to test the volume abrasion of the cables for solar power generation prepared in Examples 10-12 and Comparative Examples 1-3;

[0175] The ultraviolet aging test was carried out on the cables for solar power generation prepared in Examples 10-12 and Comparative Examples 1-3 with reference to the standard GB / T 16422.3-2022 "Plastics - Methods of exposure to laboratory light sources - Part 3: Fluorescent ultraviolet lamps". With reference to the standard GB / T 9867-2008, the change rate of volume abrasion of the cables for solar power generation after ultraviolet aging was calculated;

[0176] The limiting oxygen index of the cables for solar power generation prepared in Examples 10-12 and Comparative Examples 1-3 was tested with reference to the standard GB / T 26526-2011 "Plastics - Determination of combustion behavior by the oxygen index method - Part 2: Room temperature test";

[0177] The vertical burning grade of the cables for solar power generation prepared in Examples 10-12 and Comparative Examples 1-3 was tested with reference to the standard GB / T 2408-2021 "Plastics - Determination of flammability - Horizontal and vertical methods";

[0178] The electromagnetic interference resistance effectiveness of the cables for solar power generation prepared in Examples 10-12 and Comparative Examples 1-3 was tested with reference to the standard GB / T 32511-2016 "General technical requirements for electromagnetic shielding plastics". The specific data are shown in Table 1.

[0179] Table 1 - Performance test data table of each sample

[0180]

[0181] Data analysis:

[0182] By comparing and analyzing the data in Table 1, it can be found that the volume abrasion of the cable for solar power generation prepared by the present invention is 27 mm 3 , the change rate of volume abrasion is 101.2%, the limiting oxygen index is 42%, the vertical burning grade is V-0, and the shielding effectiveness is 81 dB for 30 MHz ≤ f < 230 MHz, 70 dB for 230 MHz ≤ f < 1 GHz, and 60 dB for 1 GHz ≤ f < 18 GHz. All the data are better than those of the comparative examples;

[0183] It is noted that the titanium dioxide modified on the surface of the composite copper frame in the present invention has high hardness and chemical stability, enhances the mechanical strength of the polymer matrix, reduces surface damage during wear, absorbs ultraviolet energy with its wide-bandgap semiconductor characteristics, converts it into heat energy dissipation, inhibits photooxidative degradation, the benzotriazole structure in the modified chain extender efficiently absorbs ultraviolet light through the conjugated system, and the excited state energy is dissipated through molecular vibration, preventing the generation of free radicals, significantly improving the anti-ultraviolet aging performance. Moreover, the silicone long chain introduced by methylphenylvinyl silicone oil has a low surface energy and high flexibility, enhancing the anti-ultraviolet stability of the molecular chain, reducing photo-initiated chain scission. The triazine group and the carbon-nitrogen double bond are introduced into the polymer chain through double bond polymerization, increasing the crosslinking density and chain rigidity, and improving the resistance to chain segment slippage. The zinc oxide component further enhances the hardness of the matrix and the wear resistance. The silicone chain segment, the modified anti-ultraviolet agent and titanium dioxide synergistically inhibit ultraviolet degradation, maintain the mechanical properties. The hard filler effect of titanium dioxide and zinc oxide and the molecular chain strengthening together improve the surface anti-wear ability, extend the service life of the cable in harsh environments, and meet the requirements of solar power generation;

[0184] It is noted that the titanium dioxide and zinc oxide modified on the surface of the composite copper frame in the present invention have high thermal stability, absorb combustion heat and form a heat insulation layer, slow down the thermal decomposition rate, inhibit flame propagation. At the same time, the methylphenylvinyl silicone oil in the modified chain extender introduces silicone chain segments, which generate a stable silicone char layer during combustion, blocking the transfer of oxygen and heat, reducing the release of combustible gases. The triazine group is incorporated into the polymer chain through double bond polymerization, and its nitrogen-containing structure releases non-combustible gases such as nitrogen at high temperatures, diluting the oxygen concentration and interrupting the combustion chain reaction. The benzotriazole structure in the modified anti-ultraviolet agent enhances the thermal stability of the molecular chain, reducing the combustible volatiles generated by high-temperature decomposition. Moreover, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide introduces a phosphorus-containing structure through phosphorus-hydrogen addition, forming phosphoric acid or polyphosphoric acid during combustion, promoting carbonization and generating a dense carbon layer, isolating oxygen and inhibiting the flame. Utilizing the synergistic effect among components, by forming a physical barrier, releasing non-combustible gases and promoting carbonization, the flame retardancy of the cable is significantly improved, ensuring safety and durability in the solar power generation system;

[0185] It is noted that the composite copper framework prepared by the present invention uses copper 1,3,5-benzenetricarboxylate as the core. Its metal copper ions have good electrical conductivity, can effectively shield external electromagnetic waves, form the Faraday cage effect, reduce the influence of electromagnetic interference on the cable transmission signal. At the same time, the surface-modified titanium dioxide and zinc oxide as high dielectric constant materials further enhance the electromagnetic wave absorption and scattering ability of the composite copper framework, weaken the electromagnetic wave penetration. And the methylphenylvinylsilicone oil in the chain extender introduces siloxane segments, and its low dielectric loss characteristic reduces the energy loss of the electrical signal in the polymer matrix, maintaining signal integrity. The triazine group and the carbon-nitrogen double bond form a highly crosslinked polymer network through double bond polymerization, enhancing the overall structural stability of the material, thereby reducing the molecular polarization effect under the action of the electromagnetic field and reducing the dielectric loss. The benzotriazole structure in the modified ultraviolet absorber stabilizes the electron cloud distribution through the conjugated system, reducing the electron migration caused by the electromagnetic field. By utilizing the synergistic effect among the components, through conductive shielding, electromagnetic wave absorption and low dielectric loss, the electromagnetic interference resistance performance of the cable is significantly improved, ensuring the stability and reliability of signal transmission in the solar power generation system;

[0186] Finally, the organic copper framework copper 1,3,5-benzenetricarboxylate is prepared by the hydrothermal method in the present invention, and the surface is modified with titanium dioxide, zinc oxide and double bond structure to obtain the composite copper framework. And the double bond is introduced into the ultraviolet absorber 4-(2H-benzotriazol-2-yl)-1,3-benzenediol by the acyl chlorination reaction to obtain the modified ultraviolet absorber, and the modified ultraviolet absorber and methylphenylvinylsilicone oil are polymerized to form a long-chain structure through the radical addition reaction, and then the composite copper framework is introduced into the long-chain structure through the capping group to obtain the modified chain extender;

[0187] And through the selection of monomers, the modified chain extender is introduced into the reaction kettle system during the double bond polymerization process. Through the double bond chain extension on the surface of the internal composite copper framework, the chain-extended polyvinylidene chloride with triazine groups and carbon-nitrogen double bonds is obtained. And by using the hydrophosphination reaction, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is loaded onto the chain-extended polyvinylidene chloride segment to obtain the modified polyvinylidene chloride. Finally, the modified polyvinylidene chloride and auxiliary materials are melt-extruded and naturally cured on the surface of the shielding layer to obtain a high-performance cable for solar power generation.

[0188] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor limit the invention to only the specific implementation manners. Obviously, according to the content of this specification, many modifications and changes can be made. These embodiments are selected and specifically described in this specification to better explain the principle and practical application of the present invention, so that those skilled in the art in the technical field can well understand and utilize the present invention. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. A flame-retardant and aging-resistant cable for solar power generation, characterized in that: It comprises a conductor layer (1), an insulating layer (2), a shielding layer (3) and an outer sheath layer (4), wherein the outer sheath layer (4) is obtained by melt-extruding a composite polyvinylidene chloride material, coating it on the surface of the shielding layer (3) and solidifying it; The composite polyvinylidene chloride material comprises the following raw materials in parts by weight: 70-80 parts of modified polyvinylidene chloride, 15-20 parts of plasticizer, 2-5 parts of stabilizer, 1-2 parts of lubricant and 1-2 parts of antioxidant; The preparation method of the modified polyvinylidene chloride comprises the following steps: A1. Add trans-1,2-dichloroethylene, 2-vinyl-4,6-diamino-1,3,5-triazine, 4-trimethylsilyl-N-tert-butyl-2-buteneimine, azobisisobutyronitrile, polytetrahydrofuran and N,N-dimethylacetamide into a high-pressure reactor, raise the temperature of the reactor to 60-80° C., keep the temperature for reaction for 1-2 hours, add a modified chain extender into the reactor, keep the temperature for reaction for 30-40 minutes, and perform post-treatment to obtain chain-extended polyvinylidene chloride; A2. Add chain-extended polyvinylidene chloride, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, aluminum chloride and N,N-dimethylacetamide into a reactor, raise the temperature of the reactor to 40-60° C., keep the reaction temperature for 1-2 hours, and perform post-treatment to obtain modified polyvinylidene chloride.

2. A flame-retardant and aging-resistant cable for solar power generation according to claim 1, characterized in that: In step A1, the amount ratio of the trans-1,2-dichloroethylene, 2-vinyl-4,6-diamino-1,3,5-triazine, 4-trimethylsilyl-N-tert-butyl-2-buteneimine, azobisisobutyronitrile, polytetrahydrofuran, N,N-dimethylacetamide and modified chain extender is 4.5-5.5g:3.6-4.4g:4.5-5.5g:1-2g:16-20mL:30-36mL:2-3g; in step A2, the amount ratio of the chain-extended polyvinylidene chloride, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, aluminum chloride and N,N-dimethylacetamide is 13-15g:4.5-5.5g:1-2g:80-90mL.

3. The flame-retardant and aging-resistant cable for solar power generation according to claim 1, characterized in that: The preparation method of the modified chain extender comprises the following steps: B1. Add 4-(2H-benzotriazole-2-yl)-1,3-benzenediol and N,N-dimethylformamide into a low-temperature reactor, introduce nitrogen protection, lower the temperature of the reactor to 0-5°C, and drop acryloyl chloride into the reactor, keep the temperature for 6-8h, and post-treat to obtain a modified anti-ultraviolet agent; B2, adding modified UV inhibitor, methylphenyl vinyl silicone oil and N,N-dimethylformamide into a reactor, and after the temperature of the reactor is raised to 60-80°C, adding azobisisobutyronitrile into the reactor, and keeping the temperature for reaction for 1-2h, adding 11-mercaptoundecyltrimethoxysilane into the reactor, and keeping the temperature for reaction for 20-30min, and post-treating to obtain a modified chain extender precursor; B3. Add the modified chain extender precursor, N,N-dimethylformamide and deionized water into the reactor and stir. The temperature of the reactor is increased to 60-80°C. A saturated sodium hydroxide aqueous solution is used to adjust the pH of the reaction system to 8-10. Add the composite copper frame into the reactor, keep warm and stir for 40-60 minutes, and post-treat to obtain the modified chain extender.

4. A flame-retardant and aging-resistant cable for solar power generation according to claim 3, characterized in that: In step B1, the amount ratio of the 4-(2H-benzotriazole-2-yl)-1,3-benzenediol, N,N-dimethylformamide and acryloyl chloride is 6.0-7.5g:36-40mL:2.4-3.0g; in step B2, the amount ratio of the modified UV inhibitor, methylphenyl vinyl silicone oil, N,N-dimethylformamide, azobisisobutyronitrile and 11-mercaptoundecyltrimethoxysilane is 8-10g:5-6g:80-90mL:1-2g:1-2g; in step B3, the amount ratio of the modified chain extender precursor, N,N-dimethylformamide, deionized water and composite copper framework is 12-15g:40-60mL:10-20mL:2-3g.

5. The flame-retardant and aging-resistant cable for solar power generation according to claim 3, characterized in that: The preparation method of the composite copper frame comprises the following steps: C1. Add the trimesic acid dispersion and the copper nitrate trihydrate dispersion into an ultrasonic instrument, and perform ultrasonic treatment at room temperature for 20-30 minutes to obtain a mixed solution; C2, adding the mixed solution into a polytetrafluoroethylene reactor, sealing the reactor and then placing it in an oven at a temperature of 110-120° C., hydrothermally reacting for 12 hours, and post-processing to obtain an organic copper framework; C3. Add anhydrous zinc acetate, titanium tetrachloride, organic copper framework and mixed solvent into an ultrasonic instrument, and perform ultrasonic treatment at room temperature for 20-30 minutes. During the ultrasonic treatment, add dopamine hydrochloride and 3-(methacryloyloxy)propyltrimethoxysilane dropwise into the ultrasonic instrument. After the ultrasonic treatment, adjust the pH value of the reaction solution to 8-9 with saturated sodium hydroxide aqueous solution, and add the reaction solution into a polytetrafluoroethylene reactor. After sealing, transfer the reactor to an oven at a temperature of 120-130°C, perform hydrothermal reaction for 24 hours, and obtain a composite copper framework by post-treatment.

6. A flame-retardant and aging-resistant cable for solar power generation according to claim 5, characterized in that: In step C1, the amount ratio of the trimesic acid dispersion and the copper nitrate trihydrate dispersion is 1 mL:1 mL, wherein the trimesic acid dispersion is obtained by mixing trimesic acid and anhydrous ethanol at a ratio of 2.0-2.4 g:25 mL, and the copper nitrate trihydrate dispersion is obtained by mixing copper nitrate trihydrate and deionized water at a ratio of 2.5-2.7 g:25 mL.

7. A method for preparing a flame-retardant and aging-resistant cable for solar power generation according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1, twisting a plurality of copper wires to obtain a conductor layer (1); S2, adding the composite polyvinyl fluoride material into a twin-screw extruder, melting and extruding it to coat the surface of the conductor layer (1), and naturally curing it to obtain the insulating layer (2); S3, wrapping the copper tape around the surface of the insulating layer (2) to obtain a shielding layer (3); S4, adding the composite polyvinylidene chloride material into a twin-screw extruder, melting and extruding it to coat the surface of the shielding layer (3), and naturally curing it to obtain an outer sheath layer (4).

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