Aging-resistant cable and method for its production

Abstract

The present application relates to the technical field of cable, in particular to a kind of anti-aging cable and preparation method thereof.The cable includes conductor, crosslinked polyethylene insulation layer, shielding layer and sheath layer from inside to outside.The sheath layer is prepared by soft polyvinyl chloride resin, butyronitrile rubber, silicon dioxide, silane coupling agent and epoxidized branched modified nano titanium dioxide.Epoxidized branched modified nano titanium dioxide is branched modified nano titanium dioxide by using epoxypropanol and epoxide compound containing naphthalene ring structure, and then modified by epoxidation of epichlorohydrin.Epoxidized branched modified nano titanium dioxide significantly improves the anti-UV aging performance of the cable, reduces the yellowing degree under long-term outdoor exposure conditions, so that the cable has longer service life and higher safety and reliability, and is suitable for various outdoor harsh environments.

Description

Technical Field

[0001] This invention relates to the field of cable technology, and in particular to an aging-resistant cable and its preparation method. Background Technology

[0002] With the development of modern industry and social infrastructure, the performance requirements for cables, as important carriers of energy transmission and information communication, are constantly increasing. Especially in outdoor applications, cables are exposed to harsh conditions such as solar ultraviolet radiation, temperature fluctuations, and rain erosion for extended periods, making them highly susceptible to aging. Cable aging not only manifests as yellowing and cracking, but more seriously, it leads to decreased insulation performance, weakened mechanical strength, and even safety accidents. Therefore, improving the aging resistance of cables, especially their resistance to ultraviolet aging, is of great significance for ensuring the stable operation of power systems and communication networks.

[0003] Traditional cable sheathing materials typically use polymers such as polyethylene and polyvinyl chloride. These materials are prone to photo-oxidation in natural environments, leading to molecular chain breakage, cross-linking, or degradation, which in turn causes material performance deterioration. To address this issue, the industry often uses methods such as adding antioxidants and ultraviolet absorbers to improve the polymer's aging resistance. However, these small-molecule additives often suffer from problems such as migration, volatilization, and precipitation, causing their protective effect to decrease significantly with prolonged use.

[0004] In recent years, nanomaterials, especially nano-titanium dioxide, have attracted widespread attention in the field of cable sheath anti-aging due to their excellent ultraviolet absorption capacity and chemical stability. Nano-titanium dioxide can effectively absorb and scatter ultraviolet light, and theoretically can be used as a highly efficient anti-aging filler. However, in practical applications, nano-titanium dioxide faces key technical challenges such as poor dispersibility and poor interfacial compatibility. Because of the high surface activity of nano-titanium dioxide, particles are prone to agglomeration, leading to uneven dispersion. This not only reduces ultraviolet absorption efficiency but may also cause a decline in the material's mechanical properties. Furthermore, the poor interfacial compatibility between nano-titanium dioxide and the polymer matrix easily forms stress concentration points at the interface, making the material more susceptible to fracture under mechanical loads. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide an aging-resistant cable and its preparation method, so as to improve the aging resistance of the cable, especially its resistance to ultraviolet aging.

[0006] To achieve the above objectives, the present invention provides an aging-resistant cable, comprising, from the inside out, a conductor, an insulation layer, a shielding layer, and a sheath layer.

[0007] The insulating layer is a cross-linked polyethylene layer.

[0008] The shielding layer is a thick aluminum-plastic composite tape with tin-plated copper wire woven on its surface.

[0009] The sheath layer is prepared from the following raw materials in parts by weight: 70-90 parts polyvinyl chloride resin, 4-6 parts nitrile rubber, 4-6 parts silica, 0.5-2 parts silane coupling agent and 15-25 parts epoxidized branched modified nano titanium dioxide.

[0010] The polyvinyl chloride resin is a flexible polyvinyl chloride resin.

[0011] The average particle size of the silica is 5-20 μm.

[0012] The silane coupling agent is silane coupling agent KH-560.

[0013] The preparation steps of the epoxidized branched nano-titanium dioxide are as follows:

[0014] S1: Under a nitrogen atmosphere, nano-titanium dioxide, glycidol and 3-(1-naphthoxy)-1,2-epoxypropane are mixed, heated to 75-85℃, and stirred for 1.5-2.5 h. Then the temperature is raised to 95-105℃ and stirred for 3-5 h. Finally, the temperature is raised to 115-125℃ and stirred for 1.5-2.5 h. The mixture is then cooled to obtain branched modified nano-titanium dioxide.

[0015] S2: Under a nitrogen atmosphere, epichlorohydrin, triethylammonium chloride and branched modified nano-titanium dioxide are mixed, heated to 75-85℃, stirred and reacted for 2-4 hours, then cooled to 55-65℃, and an 8wt%-12wt% sodium hydroxide aqueous solution is added. The reaction continues for 2-4 hours, then cooled, allowed to stand, the precipitate is removed, and rotary evaporated to obtain epoxidized branched modified nano-titanium dioxide.

[0016] The average particle size of the nano-titanium dioxide in step S1 is 10-50 nm.

[0017] In step S1, the weight ratio of nano-titanium dioxide, propylene oxide, and 3-(1-naphthoxy)-1,2-propylene oxide is 10-20:20-40:2-8.

[0018] In step S2, the weight ratio of epichlorohydrin, benzyltriethylammonium chloride, branched modified nano-titanium dioxide, and sodium hydroxide aqueous solution is 100-200:0.3-0.8:40-60:20-30.

[0019] Furthermore, the present invention also provides a method for preparing an aging-resistant cable, comprising the following steps:

[0020] (1) Polyethylene particles containing 2wt%-3wt% dicumyl peroxide crosslinking agent are extruded through an 80-100 mesh screen and wrapped on the surface of the conductor. The extrusion thickness is controlled to be 1-2mm. Then, the material is continuously vulcanized for 40-50min under a pressure of 1-1.5MPa and a temperature of 205-210℃ to obtain an insulation layer.

[0021] (2) A 0.1-0.15mm thick aluminum-plastic composite tape is spirally wrapped around the insulation layer with an overlap rate of 25%-35%. Then, tin-plated copper wire with a diameter of 0.1-0.2mm is woven on the surface with a weaving angle of 45° and a coverage rate of 85%-95% to obtain a shielding layer.

[0022] (3) Add polyvinyl chloride resin, nitrile rubber, silica, silane coupling agent and epoxidized branched nano titanium dioxide into a mixer, heat to 80-90℃, stir at 1100-1300rpm for 20-30min to obtain a mixture, and finally put the mixture into a twin-screw extruder to extrude and wrap it around the surface of the shielding layer to form a sheath layer with a wall thickness of 1.8-2.2mm, thus obtaining an aging-resistant cable.

[0023] In step (3), the temperature of the first zone of the twin-screw extruder is 155-165℃, the temperature of the second zone is 170-180℃, and the temperature of the die head is 180-190℃.

[0024] The beneficial effects of this invention are:

[0025] The aging-resistant cable provided by this invention achieves a significant improvement in overall performance through the innovative application of epoxidized branched nano-titanium dioxide. The cable's sheath material exhibits an excellent balance of mechanical properties, possessing both good tensile strength and extremely high elongation at break, enabling the cable to withstand various mechanical stresses during installation and use without easily being damaged.

[0026] The introduction of epoxidized branched nano-titanium dioxide not only enhances the basic mechanical properties of the cable, but more importantly, endows it with excellent resistance to ultraviolet aging. This modified filler can effectively absorb and scatter ultraviolet radiation, block the photo-oxidative degradation reaction chain, and protect the polymer matrix from ultraviolet damage. Even under long-term outdoor exposure conditions, the cable sheath can maintain extremely low yellowing, preserving its original appearance quality and mechanical properties, which has significant practical application value for outdoor cable products.

[0027] The introduction of the naphthalene ring structure has a multifaceted synergistic effect on improving the performance of the sheath material. First, the rigid structure of the naphthalene ring significantly enhances the stability of the nano-titanium dioxide surface and reduces the tendency of nanoparticles to aggregate. Second, the aromaticity of the naphthalene ring significantly enhances the overall system's ability to absorb ultraviolet light, acting as a highly efficient light stabilizer to prevent photodegradation of the polymer chains. Furthermore, the larger steric hindrance of the naphthalene ring promotes the formation of more open branched structures, further improving the dispersibility of nanoparticles in the polymer matrix. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0029] In the specific embodiments of the present invention, the polyvinyl chloride resin is sourced from Sinopec Qilu Petrochemical Company, model QS-800F; the nano titanium dioxide is purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., with an average particle size of 25nm and product number T104942; and the nitrile rubber is purchased from Saikede (Hengshui) Rubber & Plastics Co., Ltd., brand number LR820. Example

[0030] (1) Under a nitrogen atmosphere, 10g of nano-titanium dioxide, 20g of glycidol and 2g of 3-(1-naphthoxy)-1,2-epoxypropane were mixed, heated to 75°C and stirred for 1.5h, then heated to 95°C and stirred for 3h, and finally heated to 115°C and stirred for 1.5h, and then cooled to obtain branched modified nano-titanium dioxide.

[0031] (2) Under a nitrogen atmosphere, 100g of epichlorohydrin, 0.3g of benzyltriethylammonium chloride and 40g of branched modified nano titanium dioxide were mixed, heated to 75°C, stirred for 2h, then cooled to 55°C, 20g of 8wt% sodium hydroxide aqueous solution was added, and the reaction was continued for 2h. The mixture was then cooled, allowed to stand, the precipitate was removed, and the mixture was rotary evaporated to obtain epoxidized branched modified nano titanium dioxide.

[0032] (3) Polyethylene particles containing 2wt% dicumyl peroxide crosslinking agent are extruded through an 80-mesh filter and wrapped on the surface of the conductor. The extrusion thickness is controlled to be 1mm. Then, the material is continuously vulcanized for 40min under a pressure of 1MPa and a temperature of 205℃ to obtain an insulation layer.

[0033] (4) A 0.1mm thick aluminum-plastic composite tape is spirally wrapped around the insulation layer with an overlap rate of 25%. Then, tin-plated copper wire with a diameter of 0.1mm is woven on the surface with a weaving angle of 45° and a coverage rate of 85% to obtain a shielding layer.

[0034] (5) Add 70g of polyvinyl chloride resin, 4g of nitrile rubber, 4g of silica (average particle size 10μm), 0.5g of silane coupling agent KH-560 and 15g of epoxidized branched nano titanium dioxide into a mixer, heat to 80℃, stir at 1100rpm for 20min to obtain a mixture, and finally put the mixture into a twin-screw extruder, set the temperature of zone one to 155℃, the temperature of zone two to 170℃, and the die temperature to 180℃, and extrude it to wrap the shielding layer surface to form a sheath layer with a wall thickness of 1.8mm, thus obtaining an aging-resistant cable. Example

[0035] (1) Under a nitrogen atmosphere, 15g of nano-titanium dioxide, 30g of glycidol and 5g of 3-(1-naphthoxy)-1,2-epoxypropane were mixed, heated to 80℃ and stirred for 2h, then heated to 100℃ and stirred for 4h, and finally heated to 120℃ and stirred for 2h, and then cooled to obtain branched modified nano-titanium dioxide.

[0036] (2) Under a nitrogen atmosphere, 150g of epichlorohydrin, 0.5g of benzyltriethylammonium chloride and 50g of branched modified nano titanium dioxide were mixed, heated to 80℃, stirred and reacted for 3h, then cooled to 60℃, 25g of 10wt% sodium hydroxide aqueous solution was added, and the reaction was continued for 3h. The mixture was then cooled, allowed to stand, the precipitate was removed, and the mixture was rotary evaporated to obtain epoxidized branched modified nano titanium dioxide.

[0037] (3) Polyethylene particles containing 2.5wt% dicumyl peroxide crosslinking agent were extruded through a 90-mesh filter and wrapped on the surface of the conductor. The extrusion thickness was controlled to be 1.5mm. Then, the material was continuously vulcanized for 45min under a pressure of 1.2MPa and a temperature of 210℃ to obtain an insulation layer.

[0038] (4) A 0.12mm thick aluminum-plastic composite tape is spirally wrapped around the insulation layer with an overlap rate of 30%. Then, tin-plated copper wire with a diameter of 0.15mm is woven on the surface with a weaving angle of 45° and a coverage rate of 90% to obtain a shielding layer.

[0039] (5) Add 80g of polyvinyl chloride resin, 5g of nitrile rubber, 5g of silica (average particle size 10μm), 1g of silane coupling agent KH-560 and 20g of epoxidized branched nano titanium dioxide into a mixer, heat to 85℃, stir at 1200rpm for 25min to obtain a mixture, and finally put the mixture into a twin-screw extruder, set the temperature of zone one to 160℃, the temperature of zone two to 175℃, and the die temperature to 185℃, and extrude it to wrap the shielding layer surface to form a sheath layer with a wall thickness of 2mm, thus obtaining an aging-resistant cable. Example

[0040] (1) Under a nitrogen atmosphere, 20g of nano-titanium dioxide, 40g of glycidol and 8g of 3-(1-naphthoxy)-1,2-epoxypropane were mixed, heated to 85℃ and stirred for 2.5h, then heated to 105℃ and stirred for 5h, and finally heated to 125℃ and stirred for 2.5h, and then cooled to obtain branched modified nano-titanium dioxide;

[0041] (2) Under a nitrogen atmosphere, 200g of epichlorohydrin, 0.8g of benzyltriethylammonium chloride and 60g of branched modified nano titanium dioxide were mixed, heated to 85°C, stirred and reacted for 4h, then cooled to 65°C, 30g of 12wt% sodium hydroxide aqueous solution was added, and the reaction was continued for 4h. The mixture was then cooled, allowed to stand, the precipitate was removed, and the mixture was rotary evaporated to obtain epoxidized branched modified nano titanium dioxide.

[0042] (3) Polyethylene particles containing 3wt% dicumyl peroxide crosslinking agent are extruded through a 100-mesh filter and wrapped on the surface of the conductor. The extrusion thickness is controlled to be 2mm. Then, the material is continuously vulcanized for 50min under a pressure of 1.5MPa and a temperature of 210℃ to obtain an insulation layer.

[0043] (4) A 0.15mm thick aluminum-plastic composite tape is wrapped around the insulation layer in a spiral winding manner with an overlap rate of 35%. Then, tin-plated copper wire with a diameter of 0.2mm is woven on the surface with a weaving angle of 45° and a coverage rate of 95% to obtain a shielding layer.

[0044] (5) Add 90g of polyvinyl chloride resin, 6g of nitrile rubber, 6g of silica (average particle size 10μm), 2g of silane coupling agent KH-560 and 25g of epoxidized branched nano titanium dioxide into a mixer, heat to 90℃, stir at 1300rpm for 30min to obtain a mixture, and finally put the mixture into a twin-screw extruder, set the temperature of zone one to 165℃, the temperature of zone two to 180℃, and the die temperature to 190℃, and extrude it to wrap the shielding layer surface to form a sheath layer with a wall thickness of 2.2mm, thus obtaining an aging-resistant cable.

[0045] Comparative Example 1:

[0046] The difference between Comparative Example 1 and Example 2 is that the 20g of epoxidized branched nano-titanium dioxide in step (5) is replaced with 5g of branched modified nano-titanium dioxide;

[0047] The specific steps are as follows:

[0048] (1) Under a nitrogen atmosphere, 15g of nano-titanium dioxide, 30g of glycidol and 5g of 3-(1-naphthoxy)-1,2-epoxypropane were mixed, heated to 80℃ and stirred for 2h, then heated to 100℃ and stirred for 4h, and finally heated to 120℃ and stirred for 2h, and then cooled to obtain branched modified nano-titanium dioxide.

[0049] (2) Polyethylene particles containing 2.5wt% dicumyl peroxide crosslinking agent were extruded through a 90-mesh filter and wrapped on the surface of the conductor. The extrusion thickness was controlled to be 1.5mm. Then, the material was continuously vulcanized for 45min under a pressure of 1.2MPa and a temperature of 210℃ to obtain an insulating layer.

[0050] (3) A 0.12mm thick aluminum-plastic composite tape is spirally wrapped around the insulation layer with an overlap rate of 30%. Then, tin-plated copper wire with a diameter of 0.15mm is woven on the surface with a weaving angle of 45° and a coverage rate of 90% to obtain a shielding layer.

[0051] (4) Add 80g of polyvinyl chloride resin, 5g of nitrile rubber, 5g of silica (average particle size 10μm), 1g of silane coupling agent KH-560 and 5g of branched modified nano titanium dioxide into a mixer, heat to 85℃, stir at 1200rpm for 25min to obtain a mixture, and finally put the mixture into a twin-screw extruder, set the temperature of zone one to 160℃, the temperature of zone two to 175℃, and the die temperature to 185℃, and extrude it to wrap the shielding layer surface to form a sheath layer with a wall thickness of 2mm, thus obtaining the cable.

[0052] Comparative Example 2:

[0053] The difference between Comparative Example 2 and Example 2 is that 3-(1-naphthoxy)-1,2-epoxypropane in step (1) is replaced with glycidol;

[0054] The specific steps are as follows:

[0055] (1) Under a nitrogen atmosphere, 15g of nano-titanium dioxide and 35g of glycidol were mixed, heated to 80°C, stirred for 2h, then heated to 100°C, stirred for 4h, and finally heated to 120°C, stirred for 2h, and cooled to obtain branched modified nano-titanium dioxide.

[0056] (2) Under a nitrogen atmosphere, 150g of epichlorohydrin, 0.5g of benzyltriethylammonium chloride and 50g of branched modified nano titanium dioxide were mixed, heated to 80℃, stirred and reacted for 3h, then cooled to 60℃, 25g of 10wt% sodium hydroxide aqueous solution was added, and the reaction was continued for 3h. The mixture was then cooled, allowed to stand, the precipitate was removed, and the mixture was rotary evaporated to obtain epoxidized branched modified nano titanium dioxide.

[0057] (3) Polyethylene particles containing 2.5wt% dicumyl peroxide crosslinking agent were extruded through a 90-mesh filter and wrapped on the surface of the conductor. The extrusion thickness was controlled to be 1.5mm. Then, the material was continuously vulcanized for 45min under a pressure of 1.2MPa and a temperature of 210℃ to obtain an insulation layer.

[0058] (4) A 0.12mm thick aluminum-plastic composite tape is spirally wrapped around the insulation layer with an overlap rate of 30%. Then, tin-plated copper wire with a diameter of 0.15mm is woven on the surface with a weaving angle of 45° and a coverage rate of 90% to obtain a shielding layer.

[0059] (5) Add 80g of polyvinyl chloride resin, 5g of nitrile rubber, 5g of silica (average particle size 10μm), 1g of silane coupling agent KH-560 and 20g of epoxidized branched nano titanium dioxide into a mixer, heat to 85℃, stir at 1200rpm for 25min to obtain a mixture, and finally put the mixture into a twin-screw extruder, set the temperature of zone one to 160℃, the temperature of zone two to 175℃, and the die temperature to 185℃, and extrude it to wrap the shielding layer surface to form a sheath layer with a wall thickness of 2mm, thus obtaining the cable.

[0060] Comparative Example 3:

[0061] The difference between Comparative Example 3 and Example 2 is that 3-(1-naphthoxy)-1,2-epoxypropane in step (1) is replaced with naphthalene;

[0062] The specific steps are as follows:

[0063] (1) Under a nitrogen atmosphere, 15g of nano titanium dioxide, 30g of glycidol and 5g of naphthalene were mixed, heated to 80°C and stirred for 2h, then heated to 100°C and stirred for 4h, and finally heated to 120°C and stirred for 2h, and then cooled to obtain branched modified nano titanium dioxide.

[0064] (2) Under a nitrogen atmosphere, 150g of epichlorohydrin, 0.5g of benzyltriethylammonium chloride and 50g of branched modified nano titanium dioxide were mixed, heated to 80℃, stirred and reacted for 3h, then cooled to 60℃, 25g of 10wt% sodium hydroxide aqueous solution was added, and the reaction was continued for 3h. The mixture was then cooled, allowed to stand, the precipitate was removed, and the mixture was rotary evaporated to obtain epoxidized branched modified nano titanium dioxide.

[0065] (3) Polyethylene particles containing 2.5wt% dicumyl peroxide crosslinking agent were extruded through a 90-mesh filter and wrapped on the surface of the conductor. The extrusion thickness was controlled to be 1.5mm. Then, the material was continuously vulcanized for 45min under a pressure of 1.2MPa and a temperature of 210℃ to obtain an insulation layer.

[0066] (4) A 0.12mm thick aluminum-plastic composite tape is spirally wrapped around the insulation layer with an overlap rate of 30%. Then, tin-plated copper wire with a diameter of 0.15mm is woven on the surface with a weaving angle of 45° and a coverage rate of 90% to obtain a shielding layer.

[0067] (5) Add 80g of polyvinyl chloride resin, 5g of nitrile rubber, 5g of silica (average particle size 10μm), 1g of silane coupling agent KH-560 and 20g of epoxidized branched nano titanium dioxide into a mixer, heat to 85℃, stir at 1200rpm for 25min to obtain a mixture, and finally put the mixture into a twin-screw extruder, set the temperature of zone one to 160℃, the temperature of zone two to 175℃, and the die temperature to 185℃, and extrude it to wrap the shielding layer surface to form a sheath layer with a wall thickness of 2mm, thus obtaining the cable.

[0068] Comparative Example 4:

[0069] The difference between Comparative Example 4 and Example 2 is that the 20g of epoxy branched modified nano titanium dioxide in step (5) is replaced with a mixture of 18.5g of branched epoxy resin and 1.5g of nano titanium dioxide;

[0070] The specific steps are as follows:

[0071] (1) Under a nitrogen atmosphere, 30g of glycidol and 5g of 3-(1-naphthoxy)-1,2-epoxypropane were mixed, heated to 80°C, stirred for 2h, then heated to 100°C, stirred for 4h, and finally heated to 120°C, stirred for 2h, and then cooled to obtain branched polyol.

[0072] (2) Under a nitrogen atmosphere, 150g epichlorohydrin, 0.5g benzyltriethylammonium chloride and 35g branched polyol were mixed, heated to 80°C, stirred for 3h, then cooled to 60°C, 25g of 10wt% sodium hydroxide aqueous solution was added, and the reaction continued for 3h. The mixture was then cooled, allowed to stand, the precipitate was removed, and the mixture was rotary evaporated to obtain branched epoxy resin.

[0073] (3) Polyethylene particles containing 2.5wt% dicumyl peroxide crosslinking agent were extruded through a 90-mesh filter and wrapped on the surface of the conductor. The extrusion thickness was controlled to be 1.5mm. Then, the material was continuously vulcanized for 45min under a pressure of 1.2MPa and a temperature of 210℃ to obtain an insulation layer.

[0074] (4) A 0.12mm thick aluminum-plastic composite tape is spirally wrapped around the insulation layer with an overlap rate of 30%. Then, tin-plated copper wire with a diameter of 0.15mm is woven on the surface with a weaving angle of 45° and a coverage rate of 90% to obtain a shielding layer.

[0075] (5) Add 80g of polyvinyl chloride resin, 5g of nitrile rubber, 5g of silica (average particle size 10μm), 1g of silane coupling agent KH-560, 18.5g of branched epoxy resin and 1.5g of nano titanium dioxide to a mixer, heat to 85℃, stir at 1200rpm for 25min to obtain a mixture, and finally put the mixture into a twin-screw extruder, set the temperature of zone one to 160℃, the temperature of zone two to 175℃, and the die temperature to 185℃, and extrude it to wrap the shielding layer surface to form a sheath layer with a wall thickness of 2mm, thus obtaining the cable.

[0076] Performance testing:

[0077] Sample preparation and pretreatment: Take the cable samples prepared in Examples 1-3 and Comparative Examples 1-4, and use a dumbbell-shaped cutter to take samples from the sheath layer according to GB / T2951.11-2008 standard to prepare standard samples with a thickness of 2.0 mm. After adjusting the standard samples in an environment of 23±2℃ and 50±5% relative humidity for 24 h, they are tested.

[0078] Tensile property testing: Tests were conducted using a computer-controlled electronic tensile testing machine according to GB / T 1040.3-2006. The tensile speed was 500 mm / min, and the tensile strength and elongation at break were recorded. The results are shown in Table 1.

[0079] Ultraviolet accelerated aging test: According to GB / T 16422.3-2014, a 21-day cycle test (60℃ illumination for 8 hours / 45℃ condensation for 4 hours) was conducted on dumbbell-shaped samples of cable sheath using a UVA-340 lamp (irradiance 0.76W / m²@340nm). The yellowing index and tensile strength were tested, and the tensile strength retention rate was calculated.

[0080] Table 1 Performance Test Results

[0081] Tensile strength / MPa Elongation at break / % Tensile strength retention rate after light aging / % Yellowing index after photoaging Example 1 18.5 374 90.1 2.8 Example 2 20.3 365 92.5 2.5 Example 3 20.9 338 93.2 2.1 Comparative Example 1 22.3 275 86.3 4.8 Comparative Example 2 18.2 341 78.5 6.2 Comparative Example 3 17.1 315 80.8 5.8 Comparative Example 4 22.0 325 82.7 5.4

[0082] Data Analysis:

[0083] As can be seen from the data in Examples 1-3 of Table 1, the aging-resistant cable prepared by this invention exhibits excellent comprehensive performance. The sheath material of this cable demonstrates good tensile strength and extremely high elongation at break; this combination of mechanical properties indicates that the material possesses both strength and toughness. More notably, it exhibits excellent resistance to ultraviolet aging; the extremely low yellowing index indicates that the material can maintain good appearance quality even under long-term ultraviolet exposure, which is of great significance for cable products used outdoors.

[0084] As can be seen from the data in Table 1 for Example 2 and Comparative Example 1, although the tensile strength of Example 2 is slightly lower than that of Comparative Example 1, the elongation at break is significantly improved, and the performance after photoaging remains superior. This difference may be due to the increased amount of epoxidized branched nano-titanium dioxide and the introduction of epoxidation treatment. The introduction of epoxy groups may have played a certain plasticizing role, resulting in a higher elongation at break in the material.

[0085] As can be seen from the data in Example 2 and Comparative Example 2 in Table 1, the introduction of the naphthalene ring structure may play a key role in several aspects: its rigid structure may enhance the stability of the nano-titanium dioxide surface and reduce the tendency to aggregate; its aromaticity may enhance the absorption capacity of ultraviolet light and play an excellent light stabilizer role; its large steric hindrance may help to form a more open branched structure, improve the dispersibility of nanoparticles; during photoaging, the naphthalene ring structure may work with titanium dioxide to absorb ultraviolet energy and dissipate it through a thermal pathway, avoiding energy transfer to the polymer chain, effectively blocking the photo-oxidative degradation reaction, thereby significantly improving the material's resistance to ultraviolet aging and color stability.

[0086] As can be seen from the data in Example 2 and Comparative Example 3 in Table 1, the 3-(1-naphthoxy)-1,2-epoxypropane component has a positive effect on the modification of the surface structure of nano-titanium dioxide, and makes a significant contribution to improving the mechanical and weather resistance properties of the material. The presence of epoxy groups plays a decisive role in the modification effect, which may be due to the high reactivity of epoxy groups, which can undergo ring-opening reactions with hydroxyl groups in the branched structure to form chemical bonds, thereby achieving a more robust surface modification. In contrast, pure naphthalene molecules may only rely on physical adsorption to adhere to the surface of nanoparticles, with weak binding force, and are easy to fall off during processing and use.

[0087] As can be seen from the data in Table 1 for Example 2 and Comparative Example 4, Example 2 used epoxidized branched modified nano-titanium dioxide, while Comparative Example 4 used a simple mixture of branched epoxy resin and nano-titanium dioxide. Direct branching modification and epoxidation of the nano-titanium dioxide may have formed a chemically bonded organic layer on the particle surface. This structure may be more conducive to preventing the agglomeration of nanoparticles in the polymer matrix, resulting in a more uniform dispersion. In contrast, the simple mixing in Comparative Example 4 may lead to uneven dispersion of nanoparticles, localized agglomeration, and a reduction in the effective area of ​​interfacial interactions. Epoxidation branching modification may have formed flexible molecular chains with multifunctional groups on the nanoparticle surface. These molecular chains can both interact with the polymer matrix and provide a certain plasticizing effect, thereby significantly improving the elongation at break while maintaining the material strength. Furthermore, compared to direct mixing, the titanium dioxide and naphthalene in epoxidized branched modified nano-titanium dioxide have a closer contact, which may play a more effective synergistic role during photoaging, blocking free radical transport and chain degradation reactions, thereby maintaining the mechanical properties of the material and reducing yellowing.

[0088] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity.

Claims

1. An aging-resistant cable, characterized in that, From the inside out, it includes a conductor, an insulating layer, a shielding layer, and a sheath layer; The sheath layer is prepared from the following raw materials in the following weight proportions: 70-90 parts polyvinyl chloride resin, 4-6 parts nitrile rubber, 4-6 parts silica, 0.5-2 parts silane coupling agent and 15-25 parts epoxidized branched modified nano titanium dioxide. The preparation steps of the epoxidized branched nano-titanium dioxide are as follows: S1: Under a nitrogen atmosphere, nano-titanium dioxide, glycidol and 3-(1-naphthoxy)-1,2-epoxypropane are mixed, heated to 75-85℃, and stirred for 1.5-2.5 h. Then the temperature is raised to 95-105℃ and stirred for 3-5 h. Finally, the temperature is raised to 115-125℃ and stirred for 1.5-2.5 h. The mixture is then cooled to obtain branched modified nano-titanium dioxide. S2: Under a nitrogen atmosphere, epichlorohydrin, triethylammonium chloride and branched modified nano-titanium dioxide are mixed, heated to 75-85℃, stirred and reacted for 2-4 hours, then cooled to 55-65℃, and an 8wt%-12wt% sodium hydroxide aqueous solution is added. The reaction continues for 2-4 hours, then cooled, allowed to stand, the precipitate is removed, and rotary evaporated to obtain epoxidized branched modified nano-titanium dioxide. In step S1, the weight ratio of nano-titanium dioxide, glycidol, and 3-(1-naphthoxy)-1,2-epoxypropane is 10-20:20-40:2-8. In step S2, the weight ratio of epichlorohydrin, benzyltriethylammonium chloride, branched modified nano-titanium dioxide, and sodium hydroxide aqueous solution is 100-200:0.3-0.8:40-60:20-30.

2. The aging-resistant cable according to claim 1, characterized in that, The insulating layer is a cross-linked polyethylene layer.

3. The aging-resistant cable according to claim 1, characterized in that, The shielding layer is a thick aluminum-plastic composite tape with tin-plated copper wire woven on its surface.

4. The aging-resistant cable according to claim 1, characterized in that, The polyvinyl chloride resin is a flexible polyvinyl chloride resin.

5. The aging-resistant cable according to claim 1, characterized in that, The average particle size of the silica is 5-20 μm.

6. The aging-resistant cable according to claim 1, characterized in that, The silane coupling agent is silane coupling agent KH-560.

7. A method for preparing an aging-resistant cable according to any one of claims 1-6, characterized in that, Includes the following steps: (1) Polyethylene particles containing 2wt%-3wt% dicumyl peroxide crosslinking agent are extruded through an 80-100 mesh screen and wrapped on the surface of the conductor. The extrusion thickness is controlled to be 1-2mm. Then, the material is continuously vulcanized for 40-50min under a pressure of 1-1.5MPa and a temperature of 205-210℃ to obtain an insulation layer. (2) A 0.1-0.15mm thick aluminum-plastic composite tape is spirally wrapped around the insulation layer with an overlap rate of 25%-35%. Then, tin-plated copper wire with a diameter of 0.1-0.2mm is woven on the surface with a weaving angle of 45° and a coverage rate of 85%-95% to obtain a shielding layer. (3) Add polyvinyl chloride resin, nitrile rubber, silica, silane coupling agent and epoxidized branched nano titanium dioxide into a mixer, heat to 80-90℃, stir at 1100-1300rpm for 20-30min to obtain a mixture, and finally put the mixture into a twin-screw extruder to extrude and wrap it around the surface of the shielding layer to form a sheath layer with a wall thickness of 1.8-2.2mm, thus obtaining an aging-resistant cable.

8. The method for preparing the aging-resistant cable according to claim 7, characterized in that, In step (3), the temperature of the first zone of the twin-screw extruder is 155-165℃, the temperature of the second zone is 170-180℃, and the temperature of the die head is 180-190℃.