Anti-ultraviolet aging long-life photovoltaic cable sheath material and photovoltaic cable

Abstract

The invention discloses a photovoltaic cable sheath material with ultraviolet aging resistance and long service life. Comprising the following components in parts by weight: 100 to 120 parts of high-density polyethylene, 0.3 to 0.5 part of a benzotriazole ultraviolet light absorber, 0.5 to 0.8 part of a hindered amine light stabilizer, 0.2 to 0.5 part of an antioxidant, 3 to 5 parts of salicylate intercalated magnesium aluminum hydrotalcite, 0.02 to 0.05 part of cerium acetylacetonate, 2 to 4 parts of rutile type nano titanium dioxide, 3 to 5 parts of a compatilizer and 0.5 to 1 part of a dispersant. The photovoltaic cable is prepared from the anti-ultraviolet aging long-life photovoltaic cable sheath material, an insulating layer material and a conductor, so that the obtained photovoltaic cable sheath material and the photovoltaic cable have excellent anti-ultraviolet capability and thermal aging resistance, and have relatively long service life.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of cable preparation, in particular to an ultraviolet aging resistant long service life photovoltaic cable sheath material and cable. BACKGROUND

[0002] In the field of photovoltaic cable sheaths, the existing technology has formed a multi-layer protection system taking polyolefin base materials as the core. Traditional sheath materials mainly use polyethylene, crosslinked polyethylene and polyvinyl chloride, and construct the basic protection by adding carbon black as an ultraviolet absorber and phenolic and phosphite antioxidant agents. For example, some sheaths use thermoplastic elastomers prepared by a dynamic crosslinking process, polypropylene as a hard segment and ethylene-propylene-diene rubber as a soft segment, and combine silicone masterbatch and phosphorus flame retardants to achieve a balance of high and low temperature resistance, oil resistance and flame retardance.

[0003] However, the existing photovoltaic cables still have deficiencies in terms of ultraviolet resistance and heat aging resistance. The molecular main chain of polyolefin materials has chemical bonds that are easily activated by ultraviolet light, which can cause chain rupture or crosslinking, resulting in material surface powdering and brittle fracture. In order to achieve aging resistance, ultraviolet absorbers and antioxidants are added, which are continuously consumed under long-term or extreme environmental stress. Once depleted, the sheath material will lose protection and the aging process will accelerate rapidly. Moreover, the used additives themselves have poor migration resistance and are easily precipitated from the polymer matrix, leading to rapid degradation of the protective function. SUMMARY

[0004] In order to improve the deficiencies of traditional cable sheath materials in terms of ultraviolet resistance and heat aging resistance, an ultraviolet aging resistant long service life photovoltaic cable sheath material and cable are provided.

[0005] The above invention purpose of the application is realized by the following technical scheme: An ultraviolet aging resistant long service life photovoltaic cable sheath material, comprising the following components by weight: high density polyethylene 100-120 parts, benzotriazole ultraviolet absorber 0.3-0.5 parts, hindered amine light stabilizer 0.5-0.8 parts, antioxidant 0.2-0.5 parts, salicylate intercalated magnesium aluminum hydrotalcite 3-5 parts, rutile type nano titanium dioxide 2-4 parts, acetylacetone cerium 0.02-0.05 parts, compatibility agent 3-5 parts, dispersing agent 0.5-1 part.

[0006] By adopting the technical scheme, the linear molecular structure of high-density polyethylene as a base body provides high crystallinity and mechanical strength; the benzotriazole ultraviolet light absorber absorbs ultraviolet photons and releases harmless heat energy through intramolecular hydrogen bond action after tautomerism, and the specific molecular structure has a strong absorption bandwidth for 280-400 nm ultraviolet light, thereby improving the ultraviolet light resistance of the material; the hindered amine light stabilizer can cyclically capture alkyl radicals by generating nitroxyl radicals, and at the same time, decomposes hydroperoxide to form a synergistic protection with the ultraviolet light absorber; the ultraviolet light absorber preferentially blocks incident ultraviolet light, and the residual ultraviolet-induced radicals are captured by the hindered amine, thereby improving the ultraviolet light resistance of the material; the salicylate ion as an anion is inserted into the interlayer domain of the hydrotalcite through ion exchange action and is arranged in the direction of the layer plate to avoid salicylate precipitation, and the thermal stability is improved; the benzene ring in the molecular structure of the salicylate has a specific ortho-phenolic hydroxyl structure, which makes it an efficient ultraviolet absorption functional group; when irradiated by ultraviolet light, the structure can convert high-energy ultraviolet light energy into low-energy heat energy and release it through the breaking and forming of intramolecular hydrogen bonds, thereby protecting the polyethylene molecular chain from attack and improving the ultraviolet light resistance; the layer plate structure of the hydrotalcite has good thermal stability and can absorb heat and decompose at high temperatures, which is an endothermic reaction and helps to delay the thermal aging of the base material; the layer plate structure can hinder the diffusion and volatilization of small molecular degradation products in the polymer fluid, thereby improving the overall heat resistance and durability of the material; the rutile titanium dioxide has a very high refractive index in the ultraviolet light region, and when light passes through the interface between the two media with a large difference in refractive index, strong scattering occurs; these uniformly dispersed nanoparticles form multiple nanoscale, high-refractive-index scattering zones in the polyethylene base body, causing strong and multiple scattering of ultraviolet light during propagation, deviating the light path from the original direction, and even being reflected out of the material surface, so that the material cannot be penetrated in a straight line to cause damage; this physical shielding method itself does not consume fillers, thereby enhancing the long-term ultraviolet light resistance of the material, and the uniformly dispersed fillers in the base body limit the thermal motion of the polymer chain and delay thermal degradation; the antioxidant terminates thermal oxidation free radicals through a hydrogen-donating mechanism, and forms a high-temperature-ultraviolet double-protection network with the light stabilizer; the cerium acetylacetone can absorb the excited state or free radicals generated by the salicylate after the salicylate absorbs ultraviolet light, and the energy is directly transferred from the excited state of the salicylate to the specific f electron orbit of the cerium ion, thereby preventing the photodegradation of the salicylate and prolonging the durability of the salicylate / hydrotalcite ultraviolet light shielding function and improving the ultraviolet light resistance efficiency; the compatibilizer reduces the surface tension between the polymers, promotes the dispersion of the phases, prevents the coalescence of the dispersed phase, increases the thickness of the interface layer, increases the adhesion between the phases, improves the thermal stability, increases the stress transfer efficiency, enables each component to play a role, and enhances the ultraviolet light resistance and heat resistance and durability; the dispersant enables each component to be fully dispersed and enhances the effect of each component; in summary, the ultraviolet light resistance and aging resistance of the material are improved.

[0007] Optionally, the rutile-type nano-titanium dioxide is treated by a silane coupling agent.

[0008] By using the above technical solution, the hydrolytic group at one end of the silane coupling agent molecule can chemically react with or form a firm hydrogen bond with the hydroxyl group on the surface of the nano-titanium dioxide, and the organic functional group at the other end has good compatibility with the organic matrix such as high-density polyethylene, which improves the interface affinity, effectively reduces the agglomeration of the nano-particles, and enables them to be stably and uniformly dispersed in the matrix in the original particle size or smaller agglomerates, thereby enhancing the effect of the rutile-type nano-titanium dioxide.

[0009] Optionally, the silane coupling agent is an amino silane coupling agent.

[0010] By using the above technical solution, the amino group has high reactivity, can be more firmly combined with the surface of the nano-titanium dioxide, and the electron-rich nitrogen atom can also produce weak interaction with other additives (such as antioxidants) or groups in the matrix, further enhancing the interface adhesion, and when the material is microscopically damaged, the amino functional group can alleviate the expansion of micro-cracks through dynamic reversible hydrogen bonding, thereby improving long-term aging resistance. The treatment of the amino silane coupling agent makes the nano-titanium dioxide more stably dispersed in the matrix and more strongly combined with the interface, thereby making the ultraviolet shielding effect more durable and improving the long-term heat aging resistance of the material.

[0011] Optionally, the antioxidant includes antioxidant 1010 and dilauryl thiodipropionate.

[0012] By using the above technical solution, the two antioxidants play a synergistic chain termination and decomposition prevention role at different aging stages. Antioxidant 1010 is a typical chain termination type donor that can quickly capture alkyl radicals (R·) and alkoxy radicals (RO·) generated during the thermal oxidative aging process of the polymer, inactivates them by providing hydrogen atoms, and interrupts the radical chain reaction. Dilauryl thiodipropionate belongs to a preventive antioxidant, and its main function is to decompose hydroperoxide (ROOH), a key intermediate of thermal oxidative aging, to generate stable alcohol substances, prevent the uniform cleavage of hydroperoxide to generate new free radicals, and reduce the generation of free radicals. The combination of the two forms a double protection mechanism of "front-end prevention and end termination", which improves the long-term thermal oxidative stability of the sheath material and effectively inhibits the polymer chain scission or crosslinking caused by oxidation during the processing and long-term outdoor use of the material, thereby reducing material aging.

[0013] Optionally, the mass ratio of antioxidant 1010 to dilauryl thiodipropionate is 1:(1.5-2).

[0014] By adopting the technical scheme, the decomposition rate of the antioxidant 1010 hydrogen peroxide and the capture rate of the dilauryl thiodipropionate free radical reach a dynamic balance under the ratio, so that the synergistic antioxidant efficiency is maximized.

[0015] Optionally, the compatilizer is polyethylene grafted maleic anhydride.

[0016] By adopting the technical scheme, the polyethylene segment is similar to the high-density polyethylene matrix structure, has good compatibility, can ensure that the compatilizer molecules are embedded in the matrix well, the maleic anhydride anhydride group has high reactivity, can esterify or form strong hydrogen bonds with the hydroxyl groups on the surface of the inorganic fillers such as hydrotalcite and nano titanium dioxide in the processing process, so that the compatilizer molecules are anchored on the surface of the inorganic fillers on one end and entangled and miscible with the polyethylene matrix on the other end, the interfacial tension is reduced, the wettability is improved, high-efficiency compatibility and dispersion are realized, and the components can better play a role, and the maleic anhydride grafted to the polyethylene chain increases the cross-linking degree between polymer molecular chains, which helps to improve the thermal stability and enhance the anti-aging ability and anti-ultraviolet ability of the material.

[0017] Optionally, the dispersant is an oxidized polyethylene wax.

[0018] By adopting the technical scheme, the polar functional groups such as carboxyl and hydroxyl introduced by the oxidized polyethylene wax improve the affinity with the polar inorganic fillers, can be more effectively adsorbed on the surface of the fillers, the long-chain alkane part is compatible with the polyethylene matrix, the interaction force between the filler particles is reduced, the approach and agglomeration of the particles are effectively prevented, the viscosity of the system can be reduced during melt processing, which is beneficial to the dispersion of the fillers, the components can fully play a role, and the heat-resistant durability and anti-ultraviolet ability are improved.

[0019] The above second invention purpose of the application is realized by the following technical scheme: A photovoltaic cable comprises a conductor, an insulation layer and a sheath layer, and the sheath layer is prepared from the above-mentioned anti-ultraviolet aging long-service-life photovoltaic cable sheath material.

[0020] By adopting the technical scheme, the obtained photovoltaic cable has excellent anti-ultraviolet ability and heat aging resistance, and has a long service life.

[0021] In summary, the present application has at least the following beneficial effects: (1) The salicylate ions are inserted into the interlayer of the hydrotalcite and are arranged in a direction, and the ortho-phenolic hydroxyl groups can convert ultraviolet light energy into heat energy, improve the anti-ultraviolet property, and the hydrotalcite layer can also absorb heat and decompose, hinder the diffusion of degradation products, and improve the heat-resistant durability; (2) Rutile titanium dioxide forms high refractive index scattering area in polyethylene, which makes UV light multiple scattering, deviation or reflection, physical shielding enhances the resistance to UV, and also delays the thermal degradation of high molecular chain; (3) The compatibilizer can reduce the surface tension of the polymer, promote dispersion, prevent association, thicken the interface layer, enhance adhesion, improve thermal stability, enhance stress transfer, and enhance resistance to UV and heat durability. BRIEF DESCRIPTION OF DRAWINGS Figure 1 is a cross-sectional view of a photovoltaic cable. DETAILED DESCRIPTION

[0022] Raw materials Rutile nano-titanium dioxide with a particle size of 30-50 nm, purchased from Jiangsu Xianfeng Nanometer Material Technology Co., Ltd.; High-density polyethylene, grade Yanshan Petrochemical HDPE 5200B, purchased from Yanshan Petrochemical Company, Sinopec; Benzotriazole ultraviolet absorber, grade UV-329, purchased from Tianjin Lianlong New Material Co., Ltd.; Hindered amine light stabilizer, grade UV-3853, purchased from Tianjin Lianlong New Material Co., Ltd.; Antioxidant 1010, grade 1010, purchased from Tianjin Lianlong New Material Co., Ltd.; Dilauric acid dilauryl ester, grade DLTP, purchased from Tianjin Lianlong New Material Co., Ltd.; Cerium acetylacetone, purity ≥98%, purchased from Shanghai Maikelin Biochemical Technology Co., Ltd.; Polyethylene grafted maleic anhydride compatibilizer, grafting rate 8%, average molecular weight 5000, purchased from Shanghai Maikelin Biochemical Technology Co., Ltd.; Ethylene-acrylic acid copolymer, grade ESCOR EAA 5050, purchased from Ai Ruofu (Shanghai) New Material Technology Co., Ltd.; Oxidized polyethylene wax, softening point 135-140°C, molecular weight 4000-5000, acid value 20-30 mg KOH / g, purchased from Qingdao Sai Nuo New Material Co., Ltd.; Polyethylene wax, model SN100, softening point 105-110°C, purchased from Qingdao Sai Nuo New Material Co., Ltd.; Zinc stearate, softening point 120-130°C, zinc content 11±0.3wt%, purchased from Qingdao Sai Nuo New Material Co., Ltd.; γ-Aminopropyl triethoxysilane, γ-aminopropyl trimethoxysilane, and γ-glycidyl ether propyl trimethoxysilane, all purchased from Hangzhou Jessica Chemical Co., Ltd. Magnesium nitrate hexahydrate, aluminum nitrate nonahydrate, sodium carbonate, sodium hydroxide, salicylic acid, anhydrous ethanol, ethylene glycol and glacial acetic acid are all commercially available.

[0023] Preparation Example 1 A salicylate intercalated magnesium-aluminum hydrotalcite is prepared as follows: A sodium carbonate solution is prepared by dissolving 2.1 kg of sodium carbonate in 20 L of deionized water, and a magnesium nitrate hexahydrate solution is prepared by dissolving 30.5 kg of magnesium nitrate hexahydrate in 60 L of deionized water. 15 kg of aluminum nitrate nonahydrate is placed in a reaction bottle, 40 L of deionized water is added, and stirring is performed at a speed of 100 rpm for 5 min. The sodium carbonate solution is added, and stirring is performed at a speed of 300 rpm. The magnesium nitrate hexahydrate solution is added dropwise at a rate of 1 L / min while stirring. After the addition is complete, a sodium hydroxide solution is used to adjust the pH to 12±0.1, and the reaction is performed for 2 h. Crystallization is performed at 25℃ for 12 h. The filter cake is obtained by filtration, and water washing is performed until the pH is 7.5±0.2. Drying is performed at 70℃ for 24 h to obtain the magnesium-aluminum LDHs precursor.

[0024] The magnesium-aluminum LDHs precursor is added to 120 kg of ethylene glycol, and stirring is performed at a speed of 500 rpm to disperse it into a slurry. 5.5 kg of salicylic acid is dissolved in 20 kg of ethylene glycol, and the dispersion slurry is added at a rate of 1 L / min. A sodium hydroxide solution is used to adjust the pH to 4.5±0.1, and stirring is performed at 600 rpm and 150℃ under reflux condensation for 4 h. The filter cake is obtained by suction filtration, and the filter membrane has a pore size of 0.45 μm. Ethylene glycol is used to wash the filter cake 3 times, and drying is performed at 70℃ under vacuum for 24 h to obtain the salicylate intercalated magnesium-aluminum hydrotalcite.

[0025] Preparation Example 2 A modified rutile nano-titanium dioxide is prepared as follows: A γ-aminopropyl triethoxysilane coupling agent ethanol aqueous solution is prepared by mixing 1.5 kg of γ-aminopropyl triethoxysilane coupling agent, 3 L of anhydrous ethanol and 1.5 L of deionized water, adding glacial acetic acid to adjust the pH to 4.5±0.1, stirring at a speed of 100 rpm for 5 min, and then standing for 15 min.

[0026] 100 L of anhydrous ethanol is added to a reaction kettle, and stirring is started at a speed of 300 rpm. 10 kg of rutile nano-titanium dioxide powder is added to the reaction kettle in 5 batches, with 2 kg added each time and a 5 min interval between each batch. After all of the powder has been added, a high-speed dispersion machine is started, and the nano-titanium dioxide is dispersed in the ethanol at a speed of 8000 rpm for 45 min to obtain a nano-titanium dioxide ethanol slurry.

[0027] The γ-aminopropyl triethoxysilane coupling agent ethanol aqueous solution was added to the titanium dioxide ethanol slurry at a speed of 0.8 L / min under the condition of 300 rpm in the reaction kettle, and the temperature in the reaction kettle was set to 55°C. After the addition was completed, the reaction was carried out at this temperature for 5 h. After the reaction was completed, the heating was stopped, and the slurry was aged for 24 h. The stirring was stopped, and the titanium dioxide slurry was filtered to obtain a filter cake. The filter cake was washed with anhydrous ethanol for 3 times. The washed filter cake was dried with a vacuum box at a temperature of 80°C and a vacuum degree of -0.095 Mpa for 10 h to obtain the modified rutile type nano titanium dioxide.

[0028] Preparation Example 3 A modified rutile type nano titanium dioxide, which is different from that of Preparation Example 2 in that an equimolar amount of γ-glycidoxypropyl trimethoxysilane is used instead of γ-aminopropyl triethoxysilane, and the rest is the same as that of Preparation Example 2.

[0029] Preparation Example 4 A modified rutile type nano titanium dioxide, which is different from that of Preparation Example 2 in that an equimolar amount of γ-glycidoxypropyl trimethoxysilane is used instead of γ-aminopropyl triethoxysilane, and the rest is the same as that of Preparation Example 2.

[0030] Example 1 An ultraviolet aging resistant long service life photovoltaic cable sheath material was prepared from the following components by weight: high density polyethylene 110 kg, benzotriazole ultraviolet absorber 0.4 kg, hindered amine light stabilizer 0.7 kg, antioxidant 1010 0.105 kg, dilauryl thiodipropionate 0.195 kg, salicylate intercalated magnesium-aluminum hydrotalcite 4 kg, modified rutile type nano titanium dioxide 3 kg, cerium acetylacetonate 0.03 kg, polyethylene grafted maleic anhydride compatibilizer 4 kg, and oxidized polyethylene wax dispersant 0.8 kg. The salicylate intercalated magnesium-aluminum hydrotalcite was derived from Preparation Example 1, and the modified rutile type nano titanium dioxide was derived from Preparation Example 2.

[0031] The preparation method is as follows: S1: The high density polyethylene was added to a mixer and mixed at 500 rpm for 2 min. The oxidized polyethylene wax dispersant was added and mixed for 1 min. The benzotriazole ultraviolet absorber, hindered amine light stabilizer, antioxidant 1010, and dilauryl thiodipropionate were added in sequence, and each was mixed for 1 min. The salicylate intercalated magnesium-aluminum hydrotalcite, cerium acetylacetonate, and modified rutile type nano titanium dioxide were added and mixed for 5 min. The polyethylene grafted maleic anhydride compatibilizer was added and mixed for 5 min to obtain a premix.

[0032] S2: the premix is fed into a twin-screw extruder, extruded through a multi-hole die with a pore diameter of 3 mm, and then sent into a cooling water tank with water at a temperature of 20℃ for 30 min of cooling. After cooling is completed, the material is cut into cylindrical particles with a length of 3 mm to obtain the anti-UV aging long service life photovoltaic cable sheath material. The screw rotation speed of the twin-screw extruder is 80 rpm, and the extruder is divided into a feeding zone, a melting zone, a mixing zone, and a die head. The temperature of the feeding zone is 110℃, the temperature of the melting zone is 120℃, the temperature of the mixing zone is 130℃, and the temperature of the die head is 140℃.

[0033] Comparative Example 1 An anti-UV aging long service life photovoltaic cable sheath material, which is different from Example 1 in that no salicylate intercalated magnesium-aluminum hydrotalcite is added, and the rest is the same as Example 1.

[0034] Comparative Example 2 An anti-UV aging long service life photovoltaic cable sheath material, which is different from Example 1 in that no modified rutile-type nano-titanium dioxide is added, and the rest is the same as Example 1.

[0035] Comparative Example 3 An anti-UV aging long service life photovoltaic cable sheath material, which is different from Example 1 in that no compatibilizer is added, and the rest is the same as Example 1.

[0036] Example 2 An anti-UV aging long service life photovoltaic cable sheath material, which is different from Example 1 in that the modified rutile-type nano-titanium dioxide is derived from Preparation Example 3, and the rest is the same as Example 1.

[0037] Example 3 An anti-UV aging long service life photovoltaic cable sheath material, which is different from Example 1 in that the modified rutile-type nano-titanium dioxide is derived from Preparation Example 4, and the rest is the same as Example 1.

[0038] Example 4 An anti-UV aging long service life photovoltaic cable sheath material, which is different from Example 1 in that rutile-type nano-titanium dioxide is used instead of modified rutile-type nano-titanium dioxide, and the rest is the same as Example 1.

[0039] Example 5 An anti-UV aging long service life photovoltaic cable sheath material, which is different from Example 1 in that no antioxidant 1010 is added, and the rest is the same as Example 1.

[0040] Example 6 An anti-UV aging long service life photovoltaic cable sheath material, which is different from Example 1 in that no dodecyl sulfide is added, and the rest is the same as Example 1.

[0041] Example 7 A UV-aging resistant long-life photovoltaic cable jacket material, which is different from Example 1 in that antioxidant 1010 is 0.12 kg, dilauryl thiodipropionate is 0.18 kg, and the rest is the same as Example 1.

[0042] Example 8 A UV-aging resistant long-life photovoltaic cable jacket material, which is different from Example 1 in that antioxidant 1010 is 0.1 kg, dilauryl thiodipropionate is 0.2 kg, and the rest is the same as Example 1.

[0043] Example 9 A UV-aging resistant long-life photovoltaic cable jacket material, which is different from Example 1 in that antioxidant 1010 is 0.13 kg, dilauryl thiodipropionate is 0.17 kg, and the rest is the same as Example 1.

[0044] Example 10 A UV-aging resistant long-life photovoltaic cable jacket material, which is different from Example 1 in that antioxidant 1010 is 0.08 kg, dilauryl thiodipropionate is 0.22 kg, and the rest is the same as Example 1.

[0045] Example 11 A UV-aging resistant long-life photovoltaic cable jacket material, which is different from Example 1 in that ethylene-acrylic acid copolymer is used instead of polyethylene grafted maleic anhydride, and the rest is the same as Example 1.

[0046] Example 12 A UV-aging resistant long-life photovoltaic cable jacket material, which is different from Example 1 in that zinc stearate is used instead of oxidized polyethylene wax, and the rest is the same as Example 1.

[0047] Example 13 A UV-aging resistant long-life photovoltaic cable jacket material, which is different from Example 1 in that polyethylene wax is used instead of oxidized polyethylene wax, and the rest is the same as Example 1.

[0048] Example 14 A long-life photovoltaic cable sheath material resistant to ultraviolet aging differs from Example 1 in that: 100 kg of high-density polyethylene, 0.3 kg of benzotriazole ultraviolet absorber, 0.5 kg of hindered amine light stabilizer, 0.7 kg of antioxidant 1010, 0.13 kg of didodecyl thiodipropionate, 3 kg of salicylate-intercalated magnesium aluminum hydrotalcite, 2 kg of modified rutile nano-titanium dioxide, 0.02 kg of cerium acetylacetone, 3 kg of polyethylene-grafted maleic anhydride compatibilizer, and 0.5 kg of oxidized polyethylene wax dispersant are used. The remaining components are the same as in Example 1.

[0049] Example 15 A photovoltaic cable sheath material with anti-ultraviolet aging and long lifespan differs from Example 1 in that: 120 kg of high-density polyethylene, 0.5 kg of benzotriazole ultraviolet absorber, 0.8 kg of hindered amine light stabilizer, 0.175 kg of antioxidant 1010, 0.325 kg of didodecyl thiodipropionate, 5 kg of salicylate-intercalated magnesium aluminum hydrotalcite, 4 kg of modified rutile nano-titanium dioxide, 0.05 kg of cerium acetylacetone, 5 kg of polyethylene-grafted maleic anhydride compatibilizer, and 1 kg of oxidized polyethylene wax dispersant are used. The remaining components are the same as in Example 1.

[0050] Example 16 Combined with appendix Figure 1 As shown, a photovoltaic cable includes a conductor 1, an insulation layer 2, and a sheath layer 3. The insulation layer 2 covers the conductor 1, and the three strands of the conductor 1 covered with the insulation layer 2 are wrapped inside the sheath layer 3. The material used for the sheath layer 3 is the photovoltaic cable sheath material obtained in Example 1, and the material used for the insulation layer 2 is polyvinylidene fluoride.

[0051] The preparation method is as follows: The materials for conductor 1 and insulation layer 2 are fed into a twin-screw extruder and extruded at 100°C with a twin-screw extruder speed of 80 rpm. After cooling through a 50°C cooling water tank and a 30°C cooling water tank, the three extruded products and the materials for sheath layer 3 are fed into a twin-screw extruder and extruded at 140°C with a twin-screw extruder speed of 80 rpm. After cooling through a 50°C cooling water tank and a 30°C cooling water tank, a photovoltaic cable is obtained.

[0052] Examples 17-30 A photovoltaic cable differs from Example 16 in that the material used for the sheath layer is different, and the details of the difference are shown in Table 1.

[0053] Table 1. Details of sheathing layer materials in Examples 17-30 Sheathing layer material source Sheathing layer material source Example 17 Example 2 Example 24 Example 9 Example 18 Example 3 Example 25 Example 10 Example 19 Example 4 Example 26 Example 11 Example 20 Example 5 Example 27 Example 12 Example 21 Example 6 Example 28 Example 13 Example 22 Example 7 Example 29 Example 14 Example 23 Example 8 Example 30 Example 15 Comparative Examples 4-6 Table 2. Details of sheathing layer materials in Comparative Examples 4-6 Comparative Example 4 Comparative Example 5 Comparative Example 6 Sheathing layer material source Comparative Example 1 Comparative Example 2 Comparative Example 3 The examples 16-30 and the comparative examples 4-6 were tested, and the testing was as follows: According to GB / T 16422.2-2022 "Plastics-Laboratory light source exposure test methods Part 2: Xenon arc lamps", a xenon lamp weathering chamber was used, the wavelength was 400 nm, the irradiation intensity was 60 W / m 2 , 720 hours (360 cycles), the blackboard temperature was 65±3℃, the relative humidity was 65±5%, water was sprayed for 18 minutes and dried for 102 minutes every cycle, the tensile strength retention rate and the elongation at break retention rate were tested, and the test results were shown in Table 3.

[0054] Table 3: Test results of ultraviolet irradiation According to GB / T 2951.12-2008 "Cables and optical cables Insulation and sheath materials-General test methods Part 12: General test methods-Heat aging test methods", heat aging test was carried out, the aging temperature was 115℃, the aging time was 168h, and the tensile strength retention rate and the elongation at break retention rate were obtained and shown in Table 4.

[0055] Table 4: Test results of heat aging test Combining Table 3 and Table 4, the examples 16-30 and the comparative examples 4-6 were analyzed, and the analysis was as follows: Comparing example 16 and comparative example 4, the tensile strength retention rate and the elongation at break retention rate of example 1 after ultraviolet test were both greater than those of comparative example 4 after ultraviolet test, and the tensile strength retention rate and the elongation at break retention rate of example 16 after heat aging test were both greater than those of comparative example 4 after heat aging test.

[0056] The difference between example 16 and comparative example 4 was that the salicylate intercalated magnesium-aluminum hydrotalcite was added to the cable sheath layer material of example 16; the salicylate was inserted into the interlayer domain of the hydrotalcite to form a special structure, which could convert high-energy ultraviolet light energy into low-energy heat energy and release, improve the ultraviolet resistance, and the layer structure of the hydrotalcite had good thermal stability, which helped to delay the thermal aging of the matrix material, and the layer structure could hinder the diffusion and volatilization of small molecular degradation products in the polymer fluid, and improve the overall heat resistance durability of the material; therefore, it was necessary to add the salicylate intercalated magnesium-aluminum hydrotalcite to the cable sheath layer material.

[0057] Comparative Example 16 and Comparative Example 5, the tensile strength retention rate and the elongation at break retention rate of Example 16 after the ultraviolet test are both greater than those of Comparative Example 5 after the ultraviolet test, and the tensile strength retention rate and the elongation at break retention rate of Example 16 after the heat aging test are both greater than those of Comparative Example 5 after the heat aging test.

[0058] The difference between Example 16 and Comparative Example 5 is that the rutile nano-titanium dioxide is added in the cable sheath layer material of Example 16; the rutile titanium dioxide has a very high refractive index in the ultraviolet region, which causes strong and multiple scattering of the ultraviolet light during propagation, causes straight penetration of the material to cause deep damage, limits the thermal motion of the polymer chain in the matrix, delays thermal degradation, enhances the ultraviolet resistance and durability; therefore, it is necessary to add the rutile nano-titanium dioxide in the cable sheath layer material.

[0059] Comparative Example 16 and Comparative Example 6, the tensile strength retention rate and the elongation at break retention rate of Example 16 after the ultraviolet test are both greater than those of Comparative Example 6 after the ultraviolet test, and the tensile strength retention rate and the elongation at break retention rate of Example 16 after the heat aging test are both greater than those of Comparative Example 6 after the heat aging test.

[0060] The difference between Example 16 and Comparative Example 6 is that the compatibilizer is added in the cable sheath layer material of Example 16; the compatibilizer reduces the surface tension between the polymers, promotes the dispersion of the phases, prevents the coalescence of the dispersed phases, increases the thickness of the interface layer, increases the adhesion between the phases, improves the thermal stability, increases the stress transfer efficiency, makes each component play a role, enhances the ultraviolet resistance and heat resistance and durability; therefore, it is necessary to add the compatibilizer in the cable sheath layer material.

[0061] Comparative Example 16-17 and Example 18-19, the tensile strength retention rate and the elongation at break retention rate of Example 16-17 after the ultraviolet test are both greater than those of Example 18-19 after the ultraviolet test, and the tensile strength retention rate and the elongation at break retention rate of Example 16-17 after the heat aging test are both greater than those of Example 18-19 after the heat aging test; the tensile strength retention rate and the elongation at break retention rate of Example 18 after the ultraviolet test are both greater than those of Example 19 after the ultraviolet test, and the tensile strength retention rate and the elongation at break retention rate of Example 18 after the heat aging test are both greater than those of Example 19 after the heat aging test.

[0062] The difference between Examples 16-17, Example 18 and Example 19 is that the rutile nano-titanium dioxide is modified in the cable sheath layer material of Examples 16-18, and the rutile nano-titanium dioxide is modified by using amino silane coupling agent in the cable sheath layer material of Examples 16-17. The amino has high reactivity, can be more firmly combined with the surface of nano-titanium dioxide, and can alleviate the expansion of micro-cracks when the material is micro-damaged, and improve the long-term aging resistance. Therefore, it is more preferred to use amino silane coupling agent to modify the rutile nano-titanium dioxide in the cable sheath layer material.

[0063] Comparing Comparative Example 16 and Examples 20-21, the tensile strength retention rate and the elongation at break retention rate of Example 16 after the ultraviolet test are both greater than those of Examples 20-21 after the ultraviolet test, and the tensile strength retention rate and the elongation at break retention rate of Example 16 after the heat aging test are both greater than those of Examples 20-21 after the heat aging test.

[0064] The difference between Example 16 and Examples 20-21 is that the antioxidant 1010 and dilauryl thiodipropionate are added in the cable sheath layer material of Example 16. The two antioxidants play a synergistic chain termination and decomposition prevention effect at different aging stages. The antioxidant 1010 is a typical chain termination donor, which interrupts the free radical chain reaction, while the dilauryl thiodipropionate belongs to a preventive antioxidant, which can decompose hydroperoxide (ROOH) to prevent the generation of new free radicals from the uniform cleavage of hydroperoxide, reduce the generation of free radicals, and improve the long-term thermal-oxidative stability of the sheath material. Therefore, it is more preferred to add both antioxidant 1010 and dilauryl thiodipropionate in the cable sheath layer material.

[0065] Comparing Comparative Example 16 and Examples 22-25, the tensile strength retention rate and the elongation at break retention rate of Example 16 and Examples 22-23 after the ultraviolet test are both greater than those of Examples 24-25 after the ultraviolet test, and the tensile strength retention rate and the elongation at break retention rate of Example 16 and Examples 22-23 after the heat aging test are both greater than those of Examples 24-25 after the heat aging test.

[0066] The difference between Examples 16, 22-23, and 24-25 is as follows: In Example 16, the mass ratio of antioxidant 1010 to didodecyl thiodipropionate in the cable sheath material is 1:(1.5-2); the decomposition rate of hydroperoxide and the capture rate of free radicals reach a dynamic balance, thereby maximizing the synergistic antioxidant efficiency; therefore, a mass ratio of antioxidant 1010 to didodecyl thiodipropionate of 1:(1.5-2) in the cable sheath material is preferred.

[0067] Comparing Examples 16 and 26, the tensile strength retention rate and elongation at break retention rate of Example 16 after ultraviolet light testing are both greater than those of Example 26 after ultraviolet light testing. Furthermore, the tensile strength retention rate and elongation at break retention rate of Example 16 after heat aging testing are both greater than those of Example 26 after heat aging testing.

[0068] The difference between Example 16 and Example 26 is that the compatibilizer in the cable sheath material of Example 16 is polyethylene grafted with maleic anhydride. The polyethylene segments have good compatibility with the high-density polyethylene matrix. The maleic anhydride groups can esterify or form strong hydrogen bonds with the hydroxyl groups on the surface of inorganic fillers such as hydrotalcite and nano-titanium dioxide, reducing interfacial tension, improving wettability, and achieving efficient compatibility and dispersion, allowing each component to function better. Furthermore, the grafting of maleic anhydride onto the polyethylene chain increases the degree of cross-linking between polymer molecular chains, which helps improve thermal stability and enhances the material's anti-aging and UV resistance. Therefore, using polyethylene grafted with maleic anhydride as the compatibilizer in the cable sheath material is superior.

[0069] Comparing Examples 16 and 27-28, the tensile strength retention rate and elongation at break retention rate of Example 16 after ultraviolet light testing are both greater than those of Examples 27-28 after ultraviolet light testing. Furthermore, the tensile strength retention rate and elongation at break retention rate of Example 16 after heat aging testing are both greater than those of Examples 27-28 after heat aging testing.

[0070] The difference between Example 16 and Examples 27-28 is that the dispersant in the cable sheath material of Example 16 is oxidized polyethylene wax. Oxidized polyethylene wax can be more effectively adsorbed on the surface of the filler, has good compatibility with the polyethylene matrix, effectively prevents particles from approaching and agglomerating, reduces the viscosity of the system during melt processing, and is conducive to the dispersion of the filler, so that each component can play its role and improve the heat resistance, durability and UV resistance. Therefore, oxidized polyethylene wax is the better dispersant in the cable sheath material.

[0071] Comparing Examples 16 and 29-30, the tensile strength retention rate and elongation at break retention rate of Example 16 after ultraviolet light testing are both greater than those of Examples 29-30 after ultraviolet light testing. Furthermore, the tensile strength retention rate and elongation at break retention rate of Example 16 after heat aging testing are both greater than those of Examples 29-30 after heat aging testing.

[0072] The difference between Examples 16 and Examples 29-30 is that in Example 16, the mass ratio of high-density polyethylene, benzotriazole UV absorber, hindered amine light stabilizer, antioxidant 1010, didodecyl thiodipropionate, salicylate-intercalated magnesium aluminum hydrotalcite, modified rutile nano-titanium dioxide, cerium acetylacetone, polyethylene-grafted maleic anhydride compatibilizer, and oxidized polyethylene wax dispersant in the cable sheath material is 110:0.4:0.7:0.105:0.195:4:3:0 Therefore, the optimal mass ratio of high-density polyethylene, benzotriazole UV absorber, hindered amine light stabilizer, antioxidant 1010, didodecyl thiodipropionate, salicylate-intercalated magnesium aluminum hydrotalcite, modified rutile nano titanium dioxide, cerium acetylacetone, polyethylene-grafted maleic anhydride compatibilizer, and oxidized polyethylene wax dispersant in cable sheathing materials is 110:0.4:0.7:0.105:0.195:4:3:0.03:4:0.8.

[0073] This specific embodiment is merely an explanation of the present invention and is not intended to limit the present invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but as long as they are within the scope of protection claimed by the present invention, they are protected by patent law.

Claims

1. An ultraviolet aging resistant long life photovoltaic cable jacket material characterized in that, The components include the following parts by weight: High-density polyethylene 100~120 parts, Benzotriazole ultraviolet absorber 0.3~0.5 parts, Hindered amine light stabilizer 0.5~0.8 parts, Antioxidant 0.2~0.5 parts, Salicylate intercalation magnesium-aluminum hydrotalcite 3~5 parts, Rutile nano-titanium dioxide 2~4 parts, Acetylacetone cerium 0.02~0.05 parts, Compatibility agent 3~5 parts, Dispersing agent 0.5~1 part.

2. An ultraviolet aging resistant long life photovoltaic cable jacketing material according to claim 1, characterized in that, The rutile nano-titanium dioxide is treated by silane coupling agent.

3. An ultraviolet aging resistant long life photovoltaic cable jacketing material according to claim 2, characterized in that, The silane coupling agent is amino silane coupling agent.

4. An ultraviolet aging resistant long life photovoltaic cable jacketing material according to claim 1, characterized in that, The antioxidant includes antioxidant 1010 and dilauryl thiodipropionate.

5. An ultraviolet aging resistant long life photovoltaic cable jacketing material according to claim 4, characterized in that, The mass ratio of the antioxidant 1010 and dilauryl thiodipropionate is 1:(1.5~2).

6. An ultraviolet aging resistant long life photovoltaic cable jacketing material according to claim 1, characterized in that, The compatibility agent is polyethylene grafted maleic anhydride.

7. An ultraviolet aging resistant long life photovoltaic cable jacketing material according to claim 1, characterized in that, The dispersing agent is oxidized polyethylene wax.

8. A photovoltaic cable, characterized by It comprises a conductor (1), an insulation layer (2) and a sheath layer (3), and the sheath layer (3) is prepared from the anti-UV aging long-life photovoltaic cable sheath material of any one of claims 1~7.

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