A flame-retardant and aging-resistant cable for solar power generation and its preparation method

Abstract

The present invention discloses a flame-retardant and aging-resistant cable for solar power generation and its preparation method, belonging to the technical field of cable preparation, and is used to solve the technical problem that the flame-retardant performance and anti-ultraviolet aging performance of the cable for solar power generation in the prior art need to be further improved; the present invention includes a conductor layer, an insulating layer, a shielding layer and an outer sheath layer. An organic copper framework, copper 1,3,5-benzenetricarboxylate, is prepared by a hydrothermal method, and titanium dioxide, zinc oxide and a double bond structure are modified on its surface to obtain a composite copper framework, which is used as an auxiliary agent for a modified chain extender and participates in the preparation process of modified polyvinylidene fluoride. A high-performance cable for solar power generation is obtained by melt-extruding modified polyvinyl chloride and auxiliary materials and naturally curing them on the surface of the shielding layer.

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, which had poor flame retardancy, released a large amount of toxic gases when burning, were prone to aging and cracking under ultraviolet irradiation, and had 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, reduce the release of smoke and poisonous gases when burning, and at the same time, in view of 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, which includes, by weight: 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 the 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 that can 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 inhibition 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 hard 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 flame retardancy and anti-ultraviolet aging, 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, aiming 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 through 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 1-2 h, then add a modified chain extender into the reaction kettle, keep the temperature 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 conduct 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-butenimine 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] Furthermore, 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-butenimine, 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 conduct vacuum distillation until no liquid is collected, then chain-extended polyvinylidene chloride is obtained.

[0019] Furthermore, 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 conduct vacuum distillation until no liquid is collected, then modified polyvinylidene chloride is obtained.

[0020] Furthermore, 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 then 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 ultraviolet absorber.

[0022] B2. Add the modified ultraviolet absorber, 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, and keep the temperature for reaction for 20 - 30 min. 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 use a saturated sodium hydroxide aqueous solution to adjust the pH of the reaction system to 8 - 10. 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 ultraviolet absorber 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, and finally the composite copper framework is introduced into the interior of the organic chain segment, thus 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, an equal volume of saturated sodium bicarbonate solution is added to the reaction solution, and after stirring for 5 - 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 60 - 80 °C, and after vacuum distillation until no liquid is produced, a modified ultraviolet absorber is obtained;

[0031] Further, in step B2, the dosage ratio of the modified ultraviolet absorber, methylphenylvinyl silicone 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, when the temperature of the reaction kettle is reduced to room temperature, the reaction solution is transferred to a rotary evaporator. The temperature of the rotary evaporator is raised to 60 - 80 °C, and after vacuum distillation until no liquid is produced, a modified chain extender precursor is obtained;

[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, when the temperature of the reaction kettle is reduced to room temperature, the reaction solution is transferred to a rotary evaporator. The temperature of the rotary evaporator is raised to 60 - 80 °C, and after vacuum distillation until no liquid is produced, a modified chain extender is obtained.

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

[0034] C1. Add the trimesic acid dispersion and copper nitrate trihydrate dispersion to an ultrasonic instrument, and after ultrasonic treatment at room temperature for 20 - 30 min, a mixed solution is obtained;

[0035] C2. Add the mixed solution to 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 obtain an organic copper framework after post-treatment;

[0036] C3. Add anhydrous zinc acetate, titanium tetrachloride, the organic copper framework and a mixed solvent to an ultrasonic instrument, perform ultrasonic treatment at room temperature for 20 - 30 min, and during the ultrasonic process, drip dopamine hydrochloride and 3-(methacryloyloxy)propyltrimethoxysilane into the ultrasonic instrument. After the ultrasonic treatment is completed, use saturated sodium hydroxide aqueous solution to adjust the pH of the reaction solution to 8 - 9, and add the reaction solution to 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 obtain the composite copper framework after post-treatment.

[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 groups. These carboxylate groups 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 bonding, π-π stacking, and the coordination of copper ions. At the same time, the adhesiveness of polydopamine enhances the binding stability of the oxidant and titanium dioxide, and the carbon-carbon double bond is modified on the surface of the organic copper framework through the hydrolysis of siloxane. Finally, the composite copper framework is prepared.

[0038] Further, 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] Further, 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 a constant weight to obtain the organic copper framework.

[0040] Further, 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 a 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 a plurality of 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 wire 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 both of tribasic lead sulfate and dibutyltin dilaurate; the lubricant is one or both 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, melt extrusion is carried out on the surface of the conductor layer, and it is naturally cured to obtain an insulating layer with a thickness controlled at 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, melt extrusion is carried out on the surface of the shielding layer, and it is naturally cured to obtain an outer sheath layer with a thickness controlled at 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 a 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 of the siloxane chain segment, 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 of the chain segment to slip. 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, maintain mechanical properties. The hard filler effect of titanium dioxide and zinc oxide and the molecular chain strengthening jointly improve the surface anti-wear ability, extend the service life of the cable in harsh environments, and meet 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, slow down the thermal decomposition rate, and inhibit flame propagation. At the same time, the methylphenylvinylsilicone oil in the modified chain extender introduces a siloxane chain segment, which generates 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. And 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide introduces a phosphorus-containing structure through a phosphine addition reaction, 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 between components, by forming a physical barrier, releasing non-combustible gases, and promoting carbonization, the flame retardant performance 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 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 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 Beiwanda Biotechnology Co., Ltd., and the product number is BK-12341;

[0061] The calcium stearate used in the present invention is purchased from Tianjin Siennes 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 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 trimesic acid dispersion and 240.0 mL of 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. After sealing, the reaction kettle is transferred to 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 for vacuum drying 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. After sealing, 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 for vacuum drying 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 preparing a flame-retardant and aging-resistant cable for solar power generation, including the following steps:

[0075] Step ①: Prepare the 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: Prepare the 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 transferred to 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 the organic copper frame.

[0081] Step ③: Prepare the 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 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 the composite copper frame.

[0084] Example 3

[0085] This embodiment 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:

[0086] Step ①: Prepare the 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 device. After ultrasonic treatment at room temperature for 30 min, a mixed solution is obtained.

[0090] Step ②: Prepare the 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 transferred to 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 the organic copper framework.

[0092] Step ③: Prepare the 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 zinc acetate anhydrous, 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 device. Ultrasonic treatment is carried out 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 device. After the 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 the composite copper framework.

[0095] Example 4

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

[0097] Step Ⅰ: Prepare the 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. After holding the reaction 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 layered, the upper layer liquid is taken, and then an equal volume of absolute ethanol is added to the upper layer liquid. Then the solution is transferred to a rotary evaporator, and the temperature of the rotary evaporator is raised to 60 °C. After vacuum distillation until no liquid is collected, a modified anti-ultraviolet agent is obtained.

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

[0100] Weigh: 80.0 g of the modified anti-ultraviolet agent, 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 holding the reaction for 1 h, 10.0 g of 11-mercaptoundecyltrimethoxysilane is added to the reaction kettle. After holding the reaction 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, and the temperature of the rotary evaporator is raised to 60 °C. After vacuum distillation until no liquid is collected, a modified chain extender precursor is obtained.

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

[0102] Weigh: 120.0 g of the modified chain extender precursor, 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 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, and the temperature of the rotary evaporator is raised to 60 °C. After vacuum distillation until no liquid is collected, a modified chain extender is obtained.

[0103] Example 5

[0104] This example provides a method for preparing 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 a modified anti-ultraviolet agent

[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 introducing nitrogen for protection, 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 vacuum distillation is carried out until no liquid is collected, and a modified ultraviolet absorber is obtained.

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

[0108] Weigh: 100.0 g of modified ultraviolet absorber, 60.0 g of methylphenylvinyl silicone 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 vacuum distillation is carried out until no liquid is collected, and 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 stirring is carried out 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 vacuum distillation is carried out until no liquid is collected, and 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 for solar power generation, including the following steps:

[0113] Step I: Preparation of modified ultraviolet absorber

[0114] Weigh: 67.0 g of 4-(2H-benzotriazol-2-yl)-1,3-benzenediol and 360.0 mL of N,N-dimethylformamide were added to a low-temperature reaction kettle. After purging with nitrogen, the temperature of the reaction kettle was lowered to 3 °C, and 27.0 g of acryloyl chloride was added dropwise to the reaction kettle. After maintaining the temperature for 8 h, after the reaction was completed, an equal volume of saturated sodium bicarbonate solution was added to the reaction solution. After stirring for 6 min, when the solution was layered, the upper layer liquid was taken. Then, an equal volume of absolute ethanol was added to the upper layer liquid, and the 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, obtaining a modified chain extender precursor.

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

[0116] Weigh: 90.0 g of modified UV absorber, 54.0 g of methylphenylvinylsilicone oil and 840.0 mL of N,N-dimethylformamide were added to a reaction kettle. After the temperature of the reaction kettle was raised to 70 °C, 16.0 g of azobisisobutyronitrile was added to the reaction kettle. After maintaining the temperature for 2 h, 16.0 g of 11-mercaptoundecyltrimethoxysilane was added to the reaction kettle. After maintaining the temperature for 24 min, after the reaction was completed, when the temperature of the reaction kettle was lowered 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, obtaining 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 were added to a reaction kettle and stirred. The temperature of the reaction kettle was raised to 70 °C, and the pH of the reaction system was adjusted to 9 using a saturated sodium hydroxide aqueous solution. 21.0 g of the composite copper framework prepared in Example 3 was added to the reaction kettle, and the mixture was stirred and maintained for 50 min. After the reaction was completed, when the temperature of the reaction kettle was lowered 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, obtaining a modified chain extender.

[0119] Example 7

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

[0121] Step (i). Weighing 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 an autoclave. The temperature of the autoclave was raised to 60 °C. After holding the temperature for 1 h, 20.0 g of the modified chain extender prepared in Example 4 was added to the autoclave, and the temperature was held for 30 min. After the reaction was completed, when the temperature of the autoclave 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 vacuum distillation was carried out until no liquid was collected, and then chain-extended polyvinylidene chloride was obtained.

[0123] Step (ii), preparation of 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 reaction kettle. The temperature of the reaction kettle was raised to 40 °C, and the temperature was held for 1 h. After the reaction was completed, when the temperature of the reaction kettle 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 vacuum distillation was carried out until no liquid was collected, and then modified polyvinylidene chloride was obtained.

[0125] Example 8

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

[0127] Step (i), weigh 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 an autoclave. The temperature of the autoclave was raised to 80 °C. After holding the temperature for 2 h, 30.0 g of the modified chain extender prepared in Example 5 was added to the autoclave, and the temperature was held for 40 min. After the reaction was completed, when the temperature of the autoclave 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 vacuum distillation was carried out until no liquid was collected, and then chain-extended polyvinylidene chloride was obtained.

[0129] Step (ii), preparation of 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 maintained for 2 h. After the reaction was completed, when the temperature of the reaction kettle decreased 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 use in the preparation of 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 maintained 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 maintained for 36 min. After the reaction was completed, when the temperature of the reaction kettle decreased 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 maintained for 2 h. After the reaction was completed, when the temperature of the reaction kettle decreased 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 the 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 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 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 strip 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 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 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: 80 parts of modified polyvinylidene chloride, 15 parts of dibutyl phthalate, 5 parts of dibutyltin dilaurate, and 2 parts 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, and 210 °C in sequence. The main machine speed of the twin-screw extruder is 120 rpm, the pressure is 150 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 1.2 mm.

[0153] Step Three: Prepare the shielding layer

[0154] Wrap a copper strip 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: 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 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, and 210 °C in sequence. The main machine speed of the twin-screw extruder is 120 rpm, the pressure is 150 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 1.6 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: 72 parts of modified polyvinylidene chloride, 12 parts of dibutyl phthalate, 3 parts of dibutyltin dilaurate, and 2 parts 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, 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 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.

[0163] Step 3: Prepare the shielding layer

[0164] Wind 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 engine 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, that is, the cable for solar power generation is obtained.

[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 cancelled in the preparation process in Step ③.

[0169] Comparative Example 2

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

[0171] Comparative Example 3

[0172] The difference between this comparative example and Example 12 is that the composite chain extender is cancelled in the preparation process 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 UV 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 burning behaviour by the oxygen index - 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 burning behaviour - 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 specimen

[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, the shielding effectiveness at 30 MHz ≤ f < 230 MHz is 81 dB, the shielding effectiveness at 230 MHz ≤ f < 1 GHz is 70 dB, and the shielding effectiveness at 1 GHz ≤ f < 18 GHz is 60 dB. 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, and its wide-bandgap semiconductor property absorbs ultraviolet energy and converts it into heat energy dissipation to inhibit photo-oxidative degradation. The benzotriazole structure in the modified chain extender efficiently absorbs ultraviolet light through a conjugated system, and the excited-state energy is dissipated through molecular vibration to prevent the generation of free radicals, significantly improving the anti-ultraviolet aging performance. Moreover, the siloxane long chain introduced by methylphenylvinyl silicone oil has a low surface energy and high flexibility of the siloxane chain segment, enhancing the anti-ultraviolet stability of the molecular chain and 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 and maintain the mechanical properties. The hard filler effects of titanium dioxide and zinc oxide and the molecular chain strengthening jointly 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 the heat of combustion and form a heat-insulating layer, slow down the thermal decomposition rate, and inhibit flame propagation. At the same time, the methylphenylvinyl silicone oil in the modified chain extender introduces a siloxane chain segment, which generates a stable siloxane char layer during combustion to block the transfer of oxygen and heat and reduce 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 to dilute the oxygen concentration and interrupt the combustion chain reaction. The benzotriazole structure in the modified anti-ultraviolet agent enhances the thermal stability of the molecular chain and reduces the combustible volatiles generated by high-temperature decomposition. Moreover, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide introduces a phosphorus-containing structure through a phosphine addition reaction, which forms phosphoric acid or polyphosphoric acid during combustion, promotes carbonization, and generates a dense char layer to isolate oxygen and inhibit the flame. By utilizing the synergistic effect among the components, through the formation of a physical barrier, the release of non-combustible gases, and the promotion of carbonization, the flame retardancy of the cable is significantly improved, ensuring the safety and durability in the solar power generation system;

[0185] It is noted that the composite copper framework 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 framework, weaken the penetration of electromagnetic waves, and the methylphenylvinyl silicone oil in the chain extender introduces siloxane segments. Its low dielectric loss characteristic reduces the energy loss of the electrical signal in the polymer matrix and maintains signal integrity. The triazine group and carbon-nitrogen double bond form a highly cross-linked 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. By using 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;

[0186] Finally, the organic copper framework 1,3,5-benzenetricarboxylic acid copper 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. 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 methylphenylvinyl silicone 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 end 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 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is loaded onto the chain-extended polyvinylidene chloride segment by the phosphine-hydrogen addition reaction 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 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 includes a conductor layer (1), an insulating layer (2), a shielding layer (3) and an outer sheath layer (4). Among them, the outer sheath layer (4) is obtained by melt-extruding a composite polyvinylidene chloride material and curing it on the surface of the shielding layer (3); The composite polyvinylidene chloride material comprises raw materials in the following 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-butenimine, azobisisobutyronitrile, polytetrahydrofuran and N,N-dimethylacetamide into a high-pressure reactor. When the temperature of the reactor rises to 60-80 °C and after holding the reaction for 1-2 h, add a modified chain extender into the reactor, hold the reaction for 30-40 min, and perform post-treatment to obtain chain-extended polyvinylidene chloride; A2. Add the chain-extended polyvinylidene chloride, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, aluminum chloride and N,N-dimethylacetamide into a reactor. When the temperature of the reactor rises to 40-60 °C and hold the reaction for 1-2 h, perform post-treatment to obtain modified polyvinylidene chloride; The preparation method of the modified chain extender comprises the following steps: B1. Add 4-(2H-benzotriazol-2-yl)-1,3-benzenediol and N,N-dimethylformamide into a low-temperature reactor. After introducing nitrogen protection, lower the temperature of the reactor to 0-5 °C, and dropwise add acryloyl chloride into the reactor. Hold the reaction for 6-8 h and perform post-treatment to obtain a modified ultraviolet absorber; B2. Add the modified ultraviolet absorber, methylphenylvinylsilicone oil and N,N-dimethylformamide into a reactor. After the temperature of the reactor rises to 60-80 °C, add azobisisobutyronitrile into the reactor. After holding the reaction for 1-2 h, add 11-mercaptoundecyltrimethoxysilane into the reactor. Hold the reaction for 20-30 min and perform post-treatment to obtain a precursor of the modified chain extender; B3. Add the precursor of the modified chain extender, N,N-dimethylformamide and deionized water into a reactor and stir. Raise the temperature of the reactor to 60-80 °C, and use a saturated sodium hydroxide aqueous solution to adjust the pH of the reaction system to 8-10. Add a composite copper framework into the reactor and hold the stirring for 40-60 min. Perform post-treatment to obtain the modified chain extender.

2. The flame-retardant and aging-resistant cable for solar power generation according to claim 1, wherein 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-butenimine, 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; 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.

3. The flame-retardant and aging-resistant cable for solar power generation according to claim 1, wherein 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; in step B2, the dosage ratio of the modified ultraviolet absorber, 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; in step B3, the dosage ratio of the precursor of the modified chain extender, N,N-dimethylformamide, deionized water and the composite copper framework is 12-15 g: 40-60 mL: 10-20 mL: 2-3 g.

4. A flame-retardant and aging-resistant cable for solar power generation according to claim 1, characterized in that, The preparation method of the composite copper framework includes the following steps: C1. Add the trimesic acid dispersion and the copper nitrate trihydrate dispersion into an ultrasonic instrument, and after ultrasonic treatment at room temperature for 20-30 min, a mixed solution is obtained; C2. Add the mixed solution 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; 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, drop 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.

5. A flame-retardant and aging-resistant cable for solar power generation according to claim 4, characterized in that, In step C1, the dosage 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 absolute ethanol according to a dosage 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 according to a dosage ratio of 2.5-2.7 g: 25 mL.

6. A preparation method of a flame-retardant and aging-resistant cable for solar power generation according to any one of claims 1-5, characterized in that, It includes the following steps: S1. Strands of copper wires are stranded to obtain a conductor layer (1); S2. Add the composite polyvinyl fluoride material into a twin-screw extruder, melt and extrude it to coat the surface of the conductor layer (1), and naturally cure to obtain an insulating layer (2); S3. Wrap the copper tape around the surface of the insulating layer (2) to obtain the shielding layer (3). S4. Add the composite polyvinylidene chloride material into a twin-screw extruder, melt and extrude it to coat the surface of the shielding layer (3), and naturally cure it to obtain the outer sheath layer (4).

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