Aging-resistant cable and preparation method thereof

Abstract

The present invention relates to the field of cable material technology, and in particular to an aging-resistant cable and a preparation method thereof. The aging-resistant cable of the present invention comprises a sheath and a plurality of cables inserted into the sheath; the sheath is composed of the following raw materials in parts by weight: 90-110 parts of polyethylene, 10-20 parts of maleic anhydride grafted polyethylene, 5-10 parts of modified anti-ultraviolet agents, and 1-5 parts of cross-linking agents; the modified anti-ultraviolet agent is a mixture of double-bonded lignin powder and modified sodium lignin sulfonate powder in a weight ratio of 1-3:5-10. Compared with traditional polyethylene cables, the aging-resistant cable of the present invention has a certain degree of improvement in mechanical properties, insulation properties, and aging resistance, and can be widely used in the field of aging-resistant cables.

Description

Technical Field

[0001] The present invention relates to the technical field of cable materials, and in particular to an aging-resistant cable and a preparation method thereof. Background Art

[0002] The electric power industry is a vital sector crucial to national economy and people's livelihoods, and power transmission is a crucial component. Cables are the primary means of power transmission, making cable protection an essential component. As the first layer of protection against external damage, the performance of cable sheaths is crucial to a range of issues, including power transmission and electrical safety. This requires cable sheaths to possess excellent properties, such as mechanical strength, electrical insulation, and aging resistance, to ensure the successful construction of these high-standard power transmission channels.

[0003] In the wire and cable industry, polymers used as sheath materials include polyethylene (PE), polyvinyl chloride (PVC), polyurethane, thermoplastic elastomers, and thermoplastic polyurethane rubber. Among them, polyethylene, especially high-density polyethylene (HDPE), has become one of the most widely used sheath materials due to its excellent electrical insulation properties, good comprehensive mechanical properties, processing performance, and environmental protection.

[0004] Although HDPE has many advantages when used as a sheathing material, it has some inherent disadvantages that have significantly restricted its development in the cable field. Nanofillers have small size effects, surface and interface effects, macroscopic quantum tunneling effects, and quantum size effects. Currently, nanofillers are commonly used to enhance the mechanical properties of polymer matrix materials, enhance electrical properties, barrier properties, aging resistance, heat resistance, flame retardancy, and other properties.

[0005] Patent technology document CN114933756A discloses an aging-resistant polyethylene material, its preparation method and cable. The aging-resistant polyethylene material of the invention includes the following raw materials: polyethylene, maleic anhydride grafted polyethylene and an organic-inorganic composite agent. The organic-inorganic composite agent is an anti-ultraviolet metal oxide modified with a titanate-organic silicone composition. The cable prepared by the invention has excellent anti-ultraviolet aging performance.

[0006] Patent technical document CN116589778B discloses an aging-resistant cable protective cover, a preparation method thereof, and an aging-resistant cable. The aging-resistant cable protective cover of the invention comprises the following raw materials: a polymer base material, expandable graphite, nano-titanium dioxide, reflective particles, and an organic ultraviolet absorber; the reflective particles comprise nano-calcium carbonate and nano-barium sulfate; the particle size ratio of nano-titanium dioxide: nano-calcium carbonate: nano-barium sulfate is (5-9):(2-3):1; the cable of the invention improves the absorption effect of nano-titanium dioxide on ultraviolet rays, thereby reducing the aging effect of ultraviolet rays on the protective cover.

[0007] However, with the continuous emergence of various application environments, the performance of cables has gradually been unable to meet the needs of daily production and life. Summary of the Invention

[0008] In view of this, the object of the present invention is to provide an aging-resistant cable and a preparation method thereof, and to provide a cable with excellent insulation performance and aging resistance.

[0009] Based on the above purpose, the present invention provides an aging-resistant cable, comprising a sheath and a plurality of cables inserted into the sheath;

[0010] The sheath is composed of the following raw materials in parts by weight: 90-110 parts of polyethylene, 10-20 parts of maleic anhydride grafted polyethylene, 5-10 parts of modified anti-ultraviolet agent and 1-5 parts of cross-linking agent;

[0011] The modified anti-ultraviolet agent is prepared by mixing double-bonded lignin powder and modified sodium lignin sulfonate powder in a weight ratio of 1-3:5-10;

[0012] The preparation steps of the double-bonded lignin powder are as follows:

[0013] S11: adding alkali lignin to anhydrous ethanol and magnetically stirring at room temperature for 2 hours, then adding sodium hydroxide solution and zinc nitrate hexahydrate solution, and then heating the mixture in a water bath at 60-70°C for 30 minutes. After the reaction is completed, centrifuging, washing, and drying, the obtained solid is placed in a tube furnace and calcined at 500-600°C for 2-3 hours under a nitrogen atmosphere, cooled to room temperature, crushed, and sieved to obtain modified lignin powder;

[0014] S12: dissolving the modified lignin powder in a sodium hydroxide solution, adding allyl glycidyl ether, reacting at room temperature for 24 hours, precipitating, washing, and drying to obtain a double-bonded lignin powder;

[0015] The preparation steps of the modified sodium lignin sulfonate powder are as follows:

[0016] S21: Sodium lignin sulfonate, acrylamide, N,N-methylenebis(acrylamide) and deionized water are mixed and dissolved under magnetic stirring to obtain a mixed solution; potassium persulfate is then dissolved in deionized water to obtain a potassium persulfate solution; the mixed solution and the potassium persulfate solution are mixed and shaken thoroughly, and then TEMED is added and reacted at 40-45° C. to obtain a sodium lignin sulfonate hydrogel;

[0017] S22: Soaking the sodium lignin sulfonate hydrogel in deionized water for 12 hours, then soaking the soaked hydrogel in a mixed solution of ferrous sulfate heptahydrate and ferric chloride hexahydrate for 8-10 hours, washing with distilled water after the soaking, then transferring to a sodium hydroxide solution for 7-8 hours, washing until neutral, and soaking in distilled water for 12 hours, dehydrating at room temperature for 2-3 days, drying to constant weight, and crushing to obtain modified sodium lignin sulfonate powder;

[0018] In step S11, the usage ratio of alkali lignin, anhydrous ethanol, sodium hydroxide solution, and zinc nitrate hexahydrate solution is 1-3 g: 40-50 ml: 10-15 ml: 20-25 ml;

[0019] In step S12, the ratio of modified lignin, sodium hydroxide solution, and allyl glycidyl ether is 2-3 g: 50-70 mL: 10-15 mL;

[0020] In step S21, the ratio of sodium lignin sulfonate, acrylamide, N,N-methylenebis(acrylamide), deionized water, potassium persulfate, and TEMED is 3-5 g:10-15 g:0.2-0.3 g:120-180 g:2-2.5 g:0.4-0.6 mL;

[0021] In step 22, the ratio of the sodium lignin sulfonate hydrogel, the mixed solution, and the sodium hydroxide solution is 5-10 g: 50-100 mL: 50 mL;

[0022] The molar ratio of ferrous sulfate heptahydrate to ferric chloride hexahydrate in the mixed solution in step 22 is 1:1.4.

[0023] Preferably, the polyethylene is high-density polyethylene, and its melt index (190° C., 2.16 kg) is 0.8 g / 10 min.

[0024] Preferably, the maleic anhydride grafted polyethylene has a density of 0.92 g / ml (25° C.).

[0025] Preferably, the cross-linking agent is dicumyl peroxide.

[0026] Preferably, the concentration of the sodium hydroxide solution in step S11 is 8 mol / L.

[0027] Preferably, the concentration of the zinc nitrate hexahydrate solution in step S11 is 0.5 mol / L.

[0028] Preferably, the washing in step S12 is performed by washing with deionized water and anhydrous ethanol three times each.

[0029] Preferably, the concentration of the sodium hydroxide solution in step S12 is 2 mol / L.

[0030] Preferably, the concentration of the sodium hydroxide solution in step 22 is 1 mol / L.

[0031] Furthermore, the present invention also provides a method for preparing an aging-resistant cable, and the specific preparation steps are as follows:

[0032] Polyethylene, maleic anhydride grafted polyethylene, modified anti-ultraviolet agent and cross-linking agent are mixed and stirred evenly to obtain a mixture, which is then melt-extruded and formed to obtain a sheath. Four cables are inserted into the sheath to obtain an aging-resistant cable.

[0033] Preferably, the extrusion temperature of the extruder is 150°C in the first section, 155°C in the second section, 160°C in the third section, 160°C in the fourth section, 160°C in the fifth section, 160°C in the sixth section, 160°C in the seventh section, and 160°C in the eighth section, and the screw speed is 120r / min.

[0034] Beneficial effects of the present invention: The aging-resistant cable of the present invention has excellent mechanical strength and bending strength as well as good insulation performance. Most importantly, it has excellent aging resistance and can meet the requirements of use in various harsh environments.

[0035] The aging-resistant cable of the present invention has good UV resistance and insulation performance of lignin and sodium lignin sulfonate themselves, as well as the mutual synergy and promotion between the two, so that the obtained aging-resistant cable is superior to traditional polyethylene cables in terms of mechanical properties, insulation properties and aging resistance.

[0036] The aging-resistant cable of the present invention improves the mechanical properties, insulation properties and aging resistance of the aging-resistant cable to a certain extent by loading zinc oxide nanoparticles on the surface of lignin and Fe3O4 nanoparticles on the surface of sodium lignin sulfonate. DETAILED DESCRIPTION

[0037] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to specific embodiments.

[0038] In the mixed solution of ferrous sulfate heptahydrate and ferric chloride hexahydrate in the present invention, the molar ratio of ferrous sulfate heptahydrate to ferric chloride hexahydrate is 1:1.4.

[0039] Example 1: An aging-resistant cable, the specific preparation steps are as follows:

[0040] (1) 3 g of sodium lignin sulfonate, 10 g of acrylamide, 0.2 g of N,N-methylenebis(acrylamide) and 100 g of deionized water were mixed and dissolved by magnetic stirring to obtain a mixed solution; 2 g of potassium persulfate was then dissolved in 20 g of deionized water to obtain a potassium persulfate solution; the mixed solution and the potassium persulfate solution were mixed and shaken thoroughly, and then 0.4 mL of TEMED was added and reacted at 40°C to obtain a sodium lignin sulfonate hydrogel;

[0041] (2) 5 g of sodium lignin sulfonate hydrogel was immersed in 100 mL of deionized water for 12 h, and then immersed in 50 mL of a mixed solution of ferrous sulfate heptahydrate and ferric chloride hexahydrate for 8 h. After the soaking, it was washed with distilled water, and then transferred to 50 mL of 1 mol / L sodium hydroxide solution for 7 h. After washing until neutral, it was soaked in distilled water for 12 h, dehydrated at room temperature for 2-3 d, dried at 60 ° C to constant weight, and crushed to obtain modified sodium lignin sulfonate powder;

[0042] (3) 1 g of alkali lignin was added to 40 ml of anhydrous ethanol and magnetically stirred at room temperature for 2 h. Subsequently, 10 ml of 8 mol / L sodium hydroxide solution and 20 ml of 0.5 mol / L zinc nitrate hexahydrate solution were added. The mixture was then heated in a water bath at 60 °C for 30 min. After the reaction was completed, the mixture was centrifuged, washed with deionized water and anhydrous ethanol three times each, and dried. The obtained solid was placed in a tube furnace and calcined at 500 °C for 2 h in a nitrogen atmosphere. The solid was cooled to room temperature, crushed, and sieved to obtain modified lignin powder.

[0043] (4) 2 g of modified lignin powder was dissolved in 50 mL of 2 mol / L sodium hydroxide solution, 10 mL of allyl glycidyl ether was added, and the mixture was reacted at room temperature for 24 h. The mixture was precipitated with acetone, and the precipitated product was repeatedly washed with acetone five times and dried in vacuum at 60 °C for 48 h to obtain double-bonded lignin powder;

[0044] (5) 1 g of double-bonded lignin powder and 5 g of modified sodium lignin sulfonate powder were mixed and dispersed evenly to obtain a modified anti-ultraviolet agent;

[0045] (6) 90g of polyethylene, 10g of maleic anhydride grafted polyethylene, 5g of modified anti-ultraviolet agent and 1g of diisopropylbenzene peroxide were mixed and stirred evenly to obtain a mixture, which was then melt-extruded to obtain a sheath, wherein the extruder temperature was: 150°C for the first section, 155°C for the second section, 160°C for the third section, 160°C for the fourth section, 160°C for the fifth section, 160°C for the sixth section, 160°C for the seventh section, 160°C for the eighth section, and the screw speed was 120r / min. Four cables were inserted into the sheath to obtain an aging-resistant cable.

[0046] Example 2: An aging-resistant cable, the specific preparation steps are as follows:

[0047] (1) 4 g of sodium lignin sulfonate, 12.5 g of acrylamide, 0.25 g of N,N-methylenebis(acrylamide) and 130 g of deionized water were mixed and dissolved by magnetic stirring to obtain a mixed solution; 2.3 g of potassium persulfate was then dissolved in 25 g of deionized water to obtain a potassium persulfate solution; the mixed solution and the potassium persulfate solution were mixed and shaken thoroughly, and then 0.5 mL of TEMED was added and reacted at 43° C. to obtain a sodium lignin sulfonate hydrogel;

[0048] (2) 7.5 g of sodium lignin sulfonate hydrogel was immersed in 150 mL of deionized water for 12 h, and then immersed in 80 mL of a mixed solution of ferrous sulfate heptahydrate and ferric chloride hexahydrate for 9 h. After the soaking, it was washed with distilled water and then transferred to 50 mL of 1 mol / L sodium hydroxide solution for 7 h. After washing until neutral, it was soaked in distilled water for 12 h, dehydrated at room temperature for 2 d, dried at 63 ° C to constant weight, and crushed to obtain modified sodium lignin sulfonate powder;

[0049] (3) 2 g of alkali lignin was added to 45 ml of anhydrous ethanol and magnetically stirred at room temperature for 2 h. Subsequently, 13 ml of 8 mol / L sodium hydroxide solution and 23 ml of 0.5 mol / L zinc nitrate hexahydrate solution were added. The mixture was then heated in a water bath at 65 ° C for 30 min. After the reaction was completed, the mixture was centrifuged, washed with deionized water and anhydrous ethanol three times each, and dried. The obtained solid was placed in a tube furnace and calcined at 550 ° C for 3 h under a nitrogen atmosphere. The solid was cooled to room temperature, crushed, and sieved to obtain modified lignin powder.

[0050] (4) 2.5 g of modified lignin powder was dissolved in 60 mL of 2 mol / L sodium hydroxide solution, 13 mL of allyl glycidyl ether was added, and the mixture was reacted at room temperature for 24 h. The mixture was precipitated with acetone, and the precipitated product was repeatedly washed with acetone five times and dried in vacuum at 60 °C for 48 h to obtain double-bonded lignin powder;

[0051] (5) 2 g of double-bonded lignin powder and 8 g of modified sodium lignin sulfonate powder were mixed and dispersed evenly to obtain a modified anti-ultraviolet agent;

[0052] (6) 100 g of polyethylene, 15 g of maleic anhydride grafted polyethylene, 7.5 g of modified anti-UV agent and 3 g of diisopropylbenzene peroxide were mixed and stirred evenly to obtain a mixture, which was then melt-extruded to obtain a sheath, wherein the extruder temperature was: 150°C for the first section, 155°C for the second section, 160°C for the third section, 160°C for the fourth section, 160°C for the fifth section, 160°C for the sixth section, 160°C for the seventh section, 160°C for the eighth section, and the screw speed was 120 r / min. Four cables were inserted into the sheath to obtain an aging-resistant cable.

[0053] Example 3: An aging-resistant cable, the specific preparation steps are as follows:

[0054] (1) 5 g of sodium lignin sulfonate, 15 g of acrylamide, 0.3 g of N,N-methylenebis(acrylamide) and 150 g of deionized water were mixed and dissolved by magnetic stirring to obtain a mixed solution; 2.5 g of potassium persulfate was then dissolved in 30 g of deionized water to obtain a potassium persulfate solution; the mixed solution and the potassium persulfate solution were mixed and shaken thoroughly, and then 0.6 mL of TEMED was added and reacted at 45° C. to obtain a sodium lignin sulfonate hydrogel;

[0055] (2) 10 g of sodium lignin sulfonate hydrogel was immersed in 200 mL of deionized water for 12 h, and then immersed in 100 mL of a mixed solution of ferrous sulfate heptahydrate and ferric chloride hexahydrate for 10 h. After the soaking, it was washed with distilled water and then transferred to 50 mL of 1 mol / L sodium hydroxide solution for 8 h. After washing until neutral, it was soaked in distilled water for 12 h, dehydrated at room temperature for 3 d, dried at 65 ° C to constant weight, and crushed to obtain modified sodium lignin sulfonate powder;

[0056] (3) 3 g of alkali lignin was added to 50 ml of anhydrous ethanol and magnetically stirred at room temperature for 2 h. Subsequently, 15 ml of 8 mol / L sodium hydroxide solution and 25 ml of 0.5 mol / L zinc nitrate hexahydrate solution were added. The mixture was then heated in a water bath at 70 °C for 30 min. After the reaction was completed, the mixture was centrifuged, washed with deionized water and anhydrous ethanol three times each, and dried. The obtained solid was placed in a tube furnace and calcined at 600 °C for 3 h in a nitrogen atmosphere. The solid was cooled to room temperature, crushed, and sieved to obtain modified lignin powder.

[0057] (4) 3 g of modified lignin powder was dissolved in 70 mL of 2 mol / L sodium hydroxide solution, 15 mL of allyl glycidyl ether was added, and the mixture was reacted at room temperature for 24 h. The mixture was precipitated with acetone, and the precipitated product was repeatedly washed with acetone five times and dried in vacuum at 60 °C for 48 h to obtain double-bonded lignin powder;

[0058] (5) 3 g of double-bonded lignin powder and 10 g of modified sodium lignin sulfonate powder were mixed and dispersed evenly to obtain a modified anti-ultraviolet agent;

[0059] (6) 110 g of polyethylene, 20 g of maleic anhydride grafted polyethylene, 10 g of modified anti-UV agent and 5 g of diisopropylbenzene peroxide were mixed and stirred evenly to obtain a mixture, which was then melt-extruded to obtain a sheath, wherein the extruder temperature was: 150°C for the first section, 155°C for the second section, 160°C for the third section, 160°C for the fourth section, 160°C for the fifth section, 160°C for the sixth section, 160°C for the seventh section, and 160°C for the eighth section, and the screw speed was 120 r / min. Four cables were inserted into the sheath to obtain an aging-resistant cable.

[0060] Comparative Example 1: An aging-resistant cable, which differs from Example 2 in that it does not carry Fe3O4 nanoparticles. The specific preparation steps are as follows:

[0061] (1) 4 g of sodium lignin sulfonate, 12.5 g of acrylamide, 0.25 g of N,N-methylenebis(acrylamide) and 130 g of deionized water were mixed and dissolved by magnetic stirring to obtain a mixed solution; 2.3 g of potassium persulfate was then dissolved in 25 g of deionized water to obtain a potassium persulfate solution; the mixed solution and the potassium persulfate solution were mixed and shaken thoroughly, and then 0.5 mL of TEMED was added and reacted at 43° C. to obtain a sodium lignin sulfonate hydrogel, which was washed, dried to constant weight, and crushed to obtain a sodium lignin sulfonate powder;

[0062] (2) 2 g of alkali lignin was added to 45 ml of anhydrous ethanol and magnetically stirred at room temperature for 2 h. Subsequently, 13 ml of 8 mol / L sodium hydroxide solution and 23 ml of 0.5 mol / L zinc nitrate hexahydrate solution were added. The mixture was then heated in a water bath at 65 ° C for 30 min. After the reaction was completed, the mixture was centrifuged, washed with deionized water and anhydrous ethanol three times each, and dried. The obtained solid was placed in a tube furnace and calcined at 550 ° C for 3 h under a nitrogen atmosphere. The solid was cooled to room temperature, crushed, and sieved to obtain modified lignin powder.

[0063] (3) 2.5 g of modified lignin powder was dissolved in 60 mL of 2 mol / L sodium hydroxide solution, 13 mL of allyl glycidyl ether was added, and the mixture was reacted at room temperature for 24 h. The mixture was precipitated with acetone, and the precipitated product was repeatedly washed with acetone five times and dried in vacuum at 60 °C for 48 h to obtain double-bonded lignin powder;

[0064] (4) 2 g of double-bonded lignin powder and 8 g of sodium lignin sulfonate powder were mixed and dispersed evenly to obtain a modified anti-ultraviolet agent;

[0065] (5) 100 g of polyethylene, 15 g of maleic anhydride grafted polyethylene, 7.5 g of modified anti-UV agent and 3 g of diisopropylbenzene peroxide were mixed and stirred evenly to obtain a mixture, which was then melt-extruded to obtain a sheath, wherein the extruder temperature was: 150°C for the first section, 155°C for the second section, 160°C for the third section, 160°C for the fourth section, 160°C for the fifth section, 160°C for the sixth section, 160°C for the seventh section, and 160°C for the eighth section, and the screw speed was 120 r / min. Four cables were inserted into the sheath to obtain an aging-resistant cable.

[0066] Comparative Example 2: An aging-resistant cable, which differs from Example 2 in that the sodium lignin sulfonate hydrogel is crushed into powder and then impregnated. The specific preparation steps are as follows:

[0067] (1) 4 g of sodium lignin sulfonate, 12.5 g of acrylamide, 0.25 g of N,N-methylenebis(acrylamide) and 130 g of deionized water were mixed and dissolved by magnetic stirring to obtain a mixed solution; 2.3 g of potassium persulfate was then dissolved in 25 g of deionized water to obtain a potassium persulfate solution; the mixed solution and the potassium persulfate solution were mixed and shaken thoroughly, and then 0.5 mL of TEMED was added and reacted at 43° C. to obtain a sodium lignin sulfonate hydrogel, which was washed, dried and crushed to obtain a sodium lignin sulfonate powder;

[0068] (2) 7.5 g of sodium lignin sulfonate powder was immersed in 150 mL of deionized water for 12 h, and then immersed in 80 mL of a mixed solution of ferrous sulfate heptahydrate and ferric chloride hexahydrate for 9 h. After the soaking was completed, it was washed with distilled water and then transferred to 50 mL of 1 mol / L sodium hydroxide solution for 7 h. After washing until neutral, it was soaked in distilled water for 12 h, dehydrated at room temperature for 2 d, dried at 63 ° C to constant weight, and crushed to obtain modified sodium lignin sulfonate powder;

[0069] (3) 2 g of alkali lignin was added to 45 ml of anhydrous ethanol and magnetically stirred at room temperature for 2 h. Subsequently, 13 ml of 8 mol / L sodium hydroxide solution and 23 ml of 0.5 mol / L zinc nitrate hexahydrate solution were added. The mixture was then heated in a water bath at 65 ° C for 30 min. After the reaction was completed, the mixture was centrifuged, washed with deionized water and anhydrous ethanol three times each, and dried. The obtained solid was placed in a tube furnace and calcined at 550 ° C for 3 h under a nitrogen atmosphere. The solid was cooled to room temperature, crushed, and sieved to obtain modified lignin powder.

[0070] (4) 2.5 g of modified lignin powder was dissolved in 60 mL of 2 mol / L sodium hydroxide solution, 13 mL of allyl glycidyl ether was added, and the mixture was reacted at room temperature for 24 h. The mixture was precipitated with acetone, and the precipitated product was repeatedly washed with acetone five times and dried in vacuum at 60 °C for 48 h to obtain double-bonded lignin powder;

[0071] (5) 2 g of double-bonded lignin powder and 8 g of modified sodium lignin sulfonate powder were mixed and dispersed evenly to obtain a modified anti-ultraviolet agent;

[0072] (6) 100 g of polyethylene, 15 g of maleic anhydride grafted polyethylene, 7.5 g of modified anti-UV agent and 3 g of diisopropylbenzene peroxide were mixed and stirred evenly to obtain a mixture, which was then melt-extruded to obtain a sheath, wherein the extruder temperature was: 150°C for the first section, 155°C for the second section, 160°C for the third section, 160°C for the fourth section, 160°C for the fifth section, 160°C for the sixth section, 160°C for the seventh section, 160°C for the eighth section, and the screw speed was 120 r / min. Four cables were inserted into the sheath to obtain an aging-resistant cable.

[0073] Comparative Example 3: An aging-resistant cable, which differs from Example 2 in that sodium lignin sulfonate is replaced with lignin. The specific preparation steps are as follows:

[0074] (1) 4 g of lignin, 12.5 g of acrylamide, 0.25 g of N,N-methylenebis(acrylamide) and 130 g of deionized water were mixed and dissolved by magnetic stirring to obtain a mixed solution; 2.3 g of potassium persulfate was then dissolved in 25 g of deionized water to obtain a potassium persulfate solution; the mixed solution and the potassium persulfate solution were mixed and shaken thoroughly, and then 0.5 mL of TEMED was added and reacted at 43°C to obtain a lignin hydrogel;

[0075] (2) 7.5 g of lignin hydrogel was immersed in 150 mL of deionized water for 12 h, then immersed in 80 mL of a mixed solution of ferrous sulfate heptahydrate and ferric chloride hexahydrate for 9 h. After the soaking, it was washed with distilled water and then transferred to 50 mL of a 1 mol / L sodium hydroxide solution for 7 h. After washing until neutral, it was soaked in distilled water for 12 h, dehydrated at room temperature for 2 d, dried at 63 ° C to constant weight, and crushed to obtain modified lignin powder;

[0076] (3) 2 g of alkali lignin was added to 45 ml of anhydrous ethanol and magnetically stirred at room temperature for 2 h. Subsequently, 13 ml of 8 mol / L sodium hydroxide solution and 23 ml of 0.5 mol / L zinc nitrate hexahydrate solution were added. The mixture was then heated in a water bath at 65 ° C for 30 min. After the reaction was completed, the mixture was centrifuged, washed with deionized water and anhydrous ethanol three times each, and dried. The obtained solid was placed in a tube furnace and calcined at 550 ° C for 3 h under a nitrogen atmosphere. The solid was cooled to room temperature, crushed, and sieved to obtain zinc oxide-loaded lignin powder.

[0077] (4) 2.5 g of zinc oxide-loaded lignin powder was dissolved in 60 mL of 2 mol / L sodium hydroxide solution, 13 mL of allyl glycidyl ether was added, and the mixture was reacted at room temperature for 24 h. The mixture was precipitated with acetone, and the precipitated product was repeatedly washed with acetone five times and dried in vacuum at 60 °C for 48 h to obtain double-bonded lignin powder;

[0078] (5) 2 g of double-bonded lignin powder and 8 g of modified lignin powder were mixed and dispersed evenly to obtain a modified anti-ultraviolet agent;

[0079] (6) 100 g of polyethylene, 15 g of maleic anhydride grafted polyethylene, 7.5 g of modified anti-UV agent and 3 g of diisopropylbenzene peroxide were mixed and stirred evenly to obtain a mixture, which was then melt-extruded to obtain a sheath, wherein the extruder temperature was: 150°C for the first section, 155°C for the second section, 160°C for the third section, 160°C for the fourth section, 160°C for the fifth section, 160°C for the sixth section, 160°C for the seventh section, 160°C for the eighth section, and the screw speed was 120 r / min. Four cables were inserted into the sheath to obtain an aging-resistant cable.

[0080] Comparative Example 4: An aging-resistant cable, which differs from Example 2 in that the lignin does not load zinc oxide nanoparticles. The specific preparation steps are as follows:

[0081] (1) 4 g of sodium lignin sulfonate, 12.5 g of acrylamide, 0.25 g of N,N-methylenebis(acrylamide) and 130 g of deionized water were mixed and dissolved by magnetic stirring to obtain a mixed solution; 2.3 g of potassium persulfate was then dissolved in 25 g of deionized water to obtain a potassium persulfate solution; the mixed solution and the potassium persulfate solution were mixed and shaken thoroughly, and then 0.5 mL of TEMED was added and reacted at 43° C. to obtain a sodium lignin sulfonate hydrogel;

[0082] (2) 7.5 g of sodium lignin sulfonate hydrogel was immersed in 150 mL of deionized water for 12 h, and then immersed in 80 mL of a mixed solution of ferrous sulfate heptahydrate and ferric chloride hexahydrate for 9 h. After the soaking, it was washed with distilled water and then transferred to 50 mL of 1 mol / L sodium hydroxide solution for 7 h. After washing until neutral, it was soaked in distilled water for 12 h, dehydrated at room temperature for 2 d, dried at 63 ° C to constant weight, and crushed to obtain modified sodium lignin sulfonate powder;

[0083] (3) 2.5 g of lignin powder was dissolved in 60 mL of 2 mol / L sodium hydroxide solution, 13 mL of allyl glycidyl ether was added, and the mixture was reacted at room temperature for 24 h. The mixture was precipitated with acetone, and the precipitated product was repeatedly washed with acetone five times and dried in vacuum at 60 °C for 48 h to obtain double-bonded lignin powder;

[0084] (4) 2 g of double-bonded lignin powder and 8 g of modified sodium lignin sulfonate powder were mixed and dispersed evenly to obtain a modified anti-ultraviolet agent;

[0085] (5) 100 g of polyethylene, 15 g of maleic anhydride grafted polyethylene, 7.5 g of modified anti-UV agent and 3 g of diisopropylbenzene peroxide were mixed and stirred evenly to obtain a mixture, which was then melt-extruded to obtain a sheath, wherein the extruder temperature was: 150°C for the first section, 155°C for the second section, 160°C for the third section, 160°C for the fourth section, 160°C for the fifth section, 160°C for the sixth section, 160°C for the seventh section, and 160°C for the eighth section, and the screw speed was 120 r / min. Four cables were inserted into the sheath to obtain an aging-resistant cable.

[0086] Comparative Example 5: An aging-resistant cable, which differs from Example 2 in that the lignin is not subjected to double-bonding treatment. The specific preparation steps are as follows:

[0087] (1) 4 g of sodium lignin sulfonate, 12.5 g of acrylamide, 0.25 g of N,N-methylenebis(acrylamide) and 130 g of deionized water were mixed and dissolved by magnetic stirring to obtain a mixed solution; 2.3 g of potassium persulfate was then dissolved in 25 g of deionized water to obtain a potassium persulfate solution; the mixed solution and the potassium persulfate solution were mixed and shaken thoroughly, and then 0.5 mL of TEMED was added and reacted at 43° C. to obtain a sodium lignin sulfonate hydrogel;

[0088] (2) 7.5 g of sodium lignin sulfonate hydrogel was immersed in 150 mL of deionized water for 12 h, and then immersed in 80 mL of a mixed solution of ferrous sulfate heptahydrate and ferric chloride hexahydrate for 9 h. After the soaking, it was washed with distilled water and then transferred to 50 mL of 1 mol / L sodium hydroxide solution for 7 h. After washing until neutral, it was soaked in distilled water for 12 h, dehydrated at room temperature for 2 d, dried at 63 ° C to constant weight, and crushed to obtain modified sodium lignin sulfonate powder;

[0089] (3) 2 g of alkali lignin was added to 45 ml of anhydrous ethanol and magnetically stirred at room temperature for 2 h. Subsequently, 13 ml of 8 mol / L sodium hydroxide solution and 23 ml of 0.5 mol / L zinc nitrate hexahydrate solution were added. The mixture was then heated in a water bath at 65 ° C for 30 min. After the reaction was completed, the mixture was centrifuged, washed with deionized water and anhydrous ethanol three times each, and dried. The obtained solid was placed in a tube furnace and calcined at 550 ° C for 3 h under a nitrogen atmosphere. The solid was cooled to room temperature, crushed, and sieved to obtain modified lignin powder.

[0090] (4) 2 g of modified lignin powder and 8 g of modified sodium lignin sulfonate powder were mixed and dispersed evenly to obtain a modified anti-ultraviolet agent;

[0091] (5) 100 g of polyethylene, 15 g of maleic anhydride grafted polyethylene, 7.5 g of modified anti-UV agent and 3 g of diisopropylbenzene peroxide were mixed and stirred evenly to obtain a mixture, which was then melt-extruded to obtain a sheath, wherein the extruder temperature was: 150°C for the first section, 155°C for the second section, 160°C for the third section, 160°C for the fourth section, 160°C for the fifth section, 160°C for the sixth section, 160°C for the seventh section, and 160°C for the eighth section, and the screw speed was 120 r / min. Four cables were inserted into the sheath to obtain an aging-resistant cable.

[0092] Comparative Example 6: An aging-resistant cable, the specific preparation steps are as follows:

[0093] Mix 100g of polyethylene, 15g of maleic anhydride grafted polyethylene, 7.5g of modified anti-UV agent and 3g of diisopropylbenzene peroxide, stir evenly to obtain a mixture, and then melt-extrude to obtain a sheath, wherein the extruder temperature is: 150°C for the first section, 155°C for the second section, 160°C for the third section, 160°C for the fourth section, 160°C for the fifth section, 160°C for the sixth section, 160°C for the seventh section, 160°C for the eighth section, and the screw speed is 120r / min. Insert four cables into the sheath to obtain an aging-resistant cable.

[0094] Performance Testing

[0095] Mechanical properties test:

[0096] Tensile properties: According to ISO527, the obtained mixture was injection molded into standard dumbbell-shaped specimens, and then tensile tests were performed using a universal material testing machine at a rate of 50 mm / min. The test results are shown in Table 1.

[0097] Bending performance: According to ISO178 standard, the obtained mixture was injection molded into a model with a specimen size of 80mm×10mm×4mm. The support span of the support beam was 64mm, and the left and right sides of the indenter were 32mm each. The bending performance test was carried out at a speed of 5mm / min. The test results are shown in Table 1.

[0098] Volume resistivity: The test was performed using an electrometer. The resulting sheath was cut into 80 mm x 80 mm pieces. The average value of multiple measurements was calculated as the final result. The test results are shown in Table 1.

[0099] Aging test: The test was conducted in accordance with GB / T 2951.12-2008, "General test methods for insulation and sheathing materials of electrical and optical cables - Part 12: General test methods - Thermal aging test methods." The cable specimens were first subjected to a tensile strength test, followed by an aging test. The main steps of the test were as follows: The cable specimens were suspended in the center of an air-heated thermal aging chamber, with each specimen maintaining a minimum spacing of 20 mm from any other specimens and not in contact with the chamber's inner walls, with the exception of metal binding wires. The heating of the aging chamber was then turned on, and the timer began when the temperature reached 100°C. After 240 hours, the specimens were removed and tested for tensile strength. Aging retention = tensile strength after aging / tensile strength before aging × 100%. The test results are shown in Table 1.

[0100] Table 1 Performance test results

[0101]

[0102]

[0103] Data analysis: It can be seen from Examples 1-3 in Table 1 that the aging-resistant cable of the present invention has excellent mechanical strength and bending strength as well as good insulation performance. Most importantly, it has excellent aging resistance and can meet the requirements of use in various harsh environments.

[0104] It can be seen from Example 2 and Comparative Examples 1-6 in Table 1 that the aging-resistant cable prepared in Example 2 of the present invention is superior to the traditional polyethylene cable in Comparative Example 6 in terms of mechanical properties, insulation properties, and aging resistance. This is mainly because zinc oxide, lignin, and sodium lignin sulfonate themselves have good UV resistance and insulation properties, and all three can serve as physical reinforcement phases to improve the mechanical properties of the cable.

[0105] Example 2 and Comparative Example 3 show that the effect of compounding lignin and sodium lignin sulfonate is better than that of using only lignin to prepare the anti-ultraviolet agent. This is mainly because lignin and sodium lignin sulfonate themselves have good insulation and aging resistance. At the same time, due to the polarity advantage of sodium lignin sulfonate and the possibility that lignin itself may exist in the polyethylene cross-linked network, as well as the mutual attraction between the metal nanoparticles respectively loaded by the two, the two have a certain synergy and can promote each other, thereby greatly improving the mechanical properties, insulation and aging resistance of the aging-resistant cable. At the same time, it can promote better compatibility between the modified anti-ultraviolet agent and polyethylene, and more uniform dispersion, thereby avoiding the problem of forming a conductive network between the metal nanoparticles due to agglomeration, thereby reducing the insulation performance of the cable.

[0106] It can be illustrated by Example 2 and Comparative Examples 1 and 2 that the loaded Fe3O4 can be uniformly dispersed in the polyethylene matrix, and the tensile strength and bending strength of the material can be improved through physical entanglement and interfacial stress transfer. At the same time, it has low conductivity and after being wrapped by the insulating sodium lignin sulfonate, it can avoid forming a continuous conductive network, thereby ensuring its insulation performance. Fe3O4 itself has a certain magnetic shielding effect, which can reduce the penetration depth of ultraviolet rays, thereby ensuring its aging resistance. Most importantly, its own magnetism can attract zinc oxide in double-bonded lignin, thereby improving the compatibility between the modified anti-UV agent and the polyethylene matrix, so that the mechanical properties of the aging-resistant cable, the insulation performance or the aging resistance are all improved to a certain extent. Moreover, the use of hydrogel to load Fe3O4 can increase the loading amount of Fe3O4, thereby optimizing the performance of the aging-resistant cable to a certain extent.

[0107] It can be illustrated by Example 2 and Comparative Examples 3 and 4 that the performance of the aging-resistant cable is improved by loading zinc oxide on the surface of lignin and further double-bonding treatment. This may be because during the melt extrusion process, the double-bonded lignin can exist in the cross-linked network of polyethylene. At the same time, the loaded zinc oxide can, on the one hand, improve the mechanical strength, insulation and aging resistance of the aging-resistant cable, and on the other hand, can attract modified sodium lignin sulfonate, so that the double-bonded lignin and the modified sodium sulfonate powder have a certain synergistic effect, which can better exert the aging resistance of the modified anti-UV agent.

[0108] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present invention is limited to these examples. Within the scope of the present invention, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity.

Claims

1. An aging-resistant cable, characterized in that: It includes a sheath and a plurality of cables passing through the sheath; The sheath is composed of the following raw materials in parts by weight: 90-110 parts of polyethylene, 10-20 parts of maleic anhydride grafted polyethylene, 5-10 parts of modified anti-ultraviolet agent and 1-5 parts of cross-linking agent; The modified anti-ultraviolet agent is prepared by mixing double-bonded lignin powder and modified sodium lignin sulfonate powder in a weight ratio of 1-3:5-10; The preparation steps of the double-bonded lignin powder are as follows: S11: adding alkali lignin to anhydrous ethanol, magnetically stirring at room temperature for 2 hours, then adding sodium hydroxide solution and zinc nitrate hexahydrate solution, and then heating the mixture in a water bath at 60-70°C for 30 minutes. After the reaction is completed, centrifuging, washing, and drying, the obtained solid is placed in a tube furnace, calcined at 500-600°C for 2-3 hours in a nitrogen atmosphere, cooled to room temperature, crushed, and sieved to obtain modified lignin powder; S12: dissolving the modified lignin powder in a sodium hydroxide solution, adding allyl glycidyl ether, reacting at room temperature for 24 h, precipitating, washing, and drying to obtain double-bonded lignin; The preparation steps of the modified sodium lignin sulfonate powder are as follows: S21: Sodium lignin sulfonate, acrylamide, N,N-methylenebis(acrylamide), and deionized water are mixed and dissolved under magnetic stirring to obtain a mixed solution; potassium persulfate is then dissolved in deionized water to obtain a potassium persulfate solution; the mixed solution and the potassium persulfate solution are mixed and shaken thoroughly, and then TEMED is added and reacted at 40-45°C to obtain a sodium lignin sulfonate hydrogel; S22: Soaking the sodium lignin sulfonate hydrogel in deionized water for 12 h, then soaking the hydrogel in a mixed solution of ferrous sulfate heptahydrate and ferric chloride hexahydrate for 8-10 h, washing with distilled water after the soaking, then transferring to a sodium hydroxide solution for 7-8 h, washing until neutral, and soaking in distilled water for 12 h, dehydrating at room temperature for 2-3 d, drying to constant weight, and crushing to obtain modified sodium lignin sulfonate powder; In step S11, the usage ratio of alkali lignin, anhydrous ethanol, sodium hydroxide solution, and zinc nitrate hexahydrate solution is 1-3 g: 40-50 ml: 10-15 ml: 20-25 ml; In step S12, the ratio of the modified lignin powder, sodium hydroxide solution, and allyl glycidyl ether is 2-3 g: 50-70 mL: 10-15 mL; In step S21, the ratio of sodium lignin sulfonate, acrylamide, N,N-methylenebis(acrylamide), deionized water, potassium persulfate, and TEMED is 3-5 g:10-15 g:0.2-0.3 g:120-180 g:2-2.5 g:0.4-0.6 mL; In step 22, the ratio of the sodium lignin sulfonate hydrogel, the mixed solution, and the sodium hydroxide solution is 5-10 g: 50-100 mL: 50 mL; The molar ratio of ferrous sulfate heptahydrate to ferric chloride hexahydrate in the mixed solution in step 22 is 1:1.

4.

2. The aging-resistant cable according to claim 1, characterized in that: The polyethylene is high-density polyethylene with a melt index of 0.8 g / 10 min.

3. The aging-resistant cable according to claim 1, characterized in that: The density of the maleic anhydride grafted polyethylene is 0.92 g / ml.

4. The aging-resistant cable according to claim 1, characterized in that: The cross-linking agent is dicumyl peroxide.

5. The aging-resistant cable according to claim 1, characterized in that: The concentration of the sodium hydroxide solution in step S11 is 8 mol / L; the concentration of the zinc nitrate hexahydrate solution in step S11 is 0.5 mol / L.

6. The aging-resistant cable according to claim 1, characterized in that: The concentration of the sodium hydroxide solution in step S12 is 2 mol / L.

7. The aging-resistant cable according to claim 1, characterized in that: The concentration of the sodium hydroxide solution in step 22 is 1 mol / L.

8. A method for preparing an aging-resistant cable according to any one of claims 1 to 7, characterized in that: The specific preparation steps are as follows: Polyethylene, maleic anhydride grafted polyethylene, modified anti-ultraviolet agent and cross-linking agent are mixed and stirred evenly to obtain a mixture, which is then melt-extruded and formed to obtain a sheath. Four cables are inserted into the sheath to obtain an aging-resistant cable.

9. The method for preparing an aging-resistant cable according to claim 8, characterized in that: The extrusion temperature of the extruder is 150°C for the first section, 155°C for the second section, 160°C for the third section, 160°C for the fourth section, 160°C for the fifth section, 160°C for the sixth section, 160°C for the seventh section, and 160°C for the eighth section, and the screw speed is 120r / min.

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