High-torsion-resistance and low-smoke PVC / TPU composite cable material and preparation method thereof

Abstract

The application belongs to the technical field of cables, and particularly relates to a high-torsion-resistance and low-smoke PVC / TPU composite cable material and a preparation method thereof. The PVC and polyether TPU are used as main components of the cable material, the compatibility of the PVC and the polyether TPU is improved by adding a compatibilization aid, the mechanical strength of the cable material caused by phase separation is inhibited, the aluminum phosphate is uniformly loaded on the surface of nano silicon dioxide, the flame-retardant and smoke-suppressing agent is formed by polymerization of hexachlorocyclotriphosphazene and cyanuric acid to improve the flame-retardant performance of the cable material, the toughening filler is prepared by mixing fumed silica, cerium oxide and modified montmorillonite, the nano sheet structure can effectively block the penetration of water molecules to improve the water resistance of the cable material, and when the cable material is subjected to torsion deformation to generate microcracks, the toughening filler can prevent the rapid expansion of the cracks to improve the torsion resistance of the cable material. The composite cable material prepared by the application has excellent low-temperature resistance and water resistance, and can realize low-temperature torsion without damage.

Description

Technical Field

[0001] This invention belongs to the field of cable technology, specifically relating to a high-torsion, low-smoke PVC / TPU composite cable material and its preparation method. Background Technology

[0002] Polyvinyl chloride (PVC) is inexpensive and possesses advantages such as good insulation properties, high cost-effectiveness, inherent flame retardancy, and long service life, making it one of the main materials for cable materials. Because the processing temperature of PVC is higher than its decomposition temperature, additives are needed to improve its processability. Furthermore, when used alone, PVC is prone to permanent deformation under frequent twisting at low temperatures. Thermoplastic polyurethane (TPU) is a rubber-like elastomer material with excellent mechanical properties and flexibility, but it suffers from high cost, poor aging resistance, and poor flame retardancy. Current technology often blends PVC and TPU to combine the advantages of both in cable materials. However, direct blending of PVC and polyether-type TPU currently presents compatibility issues. Under high-intensity torsion, stress concentration points form at the phase separation interface, causing fatigue cracking of the material. Therefore, a third component is needed to improve the compatibility between PVC and polyether-type TPU.

[0003] Chinese invention patent CN120748827B discloses a torsion-resistant cross-linked polyethylene (XLPE) insulated cable suitable for scenarios involving intermittent winding and static cycles, such as cable logistics warehousing and mobile emergency equipment. Existing technologies, designed for continuous winding, cannot address the residual stress generated by the rigidity of cross-linked polyethylene in intermittent scenarios, nor the aging and crack propagation problems caused by the coupling of residual stress with the environment. This invention incorporates a gradient porous stress-relieving layer outside the conductor, releasing residual stress and strengthening interfacial bonding through modulus transition and chemical adhesion; the XLPE insulation layer is modified with EVA to reduce rigidity and reinforced with nano-silica; and a self-healing layer containing directional microcapsules and carbon nanotubes is added outside the insulation layer to achieve precise crack repair and anti-aging, reducing insulation cracks, conductor breakage, and shielding failure during intermittent winding and static cycles, ensuring the cable's reliability in the target scenarios. However, existing technologies suffer from insufficient mechanical strength due to the direct mixing of polyether-type TPU and PVC. Summary of the Invention

[0004] The purpose of this invention is to provide a high-torsion, low-smoke PVC / TPU composite cable material and its preparation method, which solves the technical problem of insufficient mechanical strength in the prior art when polyether-type TPU and PVC are directly mixed.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A high-torsion, low-smoke PVC / TPU composite cable material comprises the following raw materials in parts by weight: 20-30 parts PVC, 70-80 parts polyether-type TPU, 10-15 parts compatibilizer, 2-6 parts chlorinated polyethylene, 1-5 parts flame retardant and smoke suppressant, 3-10 parts toughening filler, 1-3 parts maleic anhydride-grafted ethylene-vinyl acetate copolymer, 1-10 parts dioctyl phthalate plasticizer, 0.5-2 parts heat stabilizer, 0.5-2 parts antioxidant, and 1-10 parts coloring carbon black;

[0007] The compatibilizer is one or more combinations of ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, and ethylene-butyl acrylate copolymer;

[0008] The heat stabilizer is one or more of zinc stearate, calcium stearate, calcium acetylacetonate and zinc acetylacetonate;

[0009] The antioxidant is one or more of antioxidant 1010, antioxidant 168, and antioxidant 9012.

[0010] Preferably, the preparation method of the flame retardant and smoke suppressant includes the following steps:

[0011] S11. Add 25wt% ammonia solution and deionized water to ethanol, slowly add tetraethyl orthosilicate, stir the reaction, filter to collect the solid, wash and dry to obtain nano-silica. Add nano-silica to 50% ethanol solution, add KH-560, heat and stir to modify, filter to collect the solid, wash and dry to obtain modified nano-silica.

[0012] S12. Modified nano-silica was added to a 50% ethanol aqueous solution, and hydrochloric acid was added to adjust the pH to obtain dispersion A. Phosphoric acid and aluminum hydroxide were added to deionized water to dissolve to obtain solution B. Solution B was slowly added dropwise to dispersion A and stirred to react. 25wt% ammonia aqueous solution was added dropwise for aging. The solid was collected by filtration, washed and dried to obtain nano-template.

[0013] S13. Add hexachlorocyclotriphosphazene and acetonitrile to a reaction vessel, add triethanolamine acid, add nanotemplate and cyanuric acid, heat to react, centrifuge and filter to collect the solid, wash and vacuum dry to obtain flame retardant and smoke suppressant.

[0014] Preferably, the volume ratio of 25wt% ammonia solution, deionized water, ethanol and tetraethyl orthosilicate in S11 is 3~5:7~10:70~80:5~7. The mixture is stirred at 30~40℃ and 500~1000rpm for 30~50min. The solid is collected by filtration, washed with deionized water, and dried at 50~60℃.

[0015] Preferably, the ratio of nano-silica, 50% ethanol aqueous solution and KH-560 in S11 is (1~3) g: (50~60) mL: (5~6) mL. The mixture is heated to 40~60℃ and stirred at 300~500 rpm for 4~6 h. It is then washed with deionized water and dried at 50~60℃.

[0016] Preferably, in S12, the mass ratio of modified nano-silica to 50% ethanol aqueous solution in dispersion A is 5~8:100, and hydrochloric acid is added to adjust the pH to 2~3. The mass ratio of phosphoric acid, aluminum hydroxide, and deionized water in solution B is 40~45:5~8:100, and the mass ratio of solution A to solution B is 10~15:1. The reaction is stirred at 1000~2000 rpm for 20~30 min, and 25wt% ammonia aqueous solution is added dropwise to adjust the pH to 5~6.5. The mixture is then aged for 2~3 h, washed with deionized water, and dried at 50~60℃.

[0017] Preferably, the ratio of hexachlorocyclotriphosphazene, acetonitrile, triethanolamine, nanotemplate, and cyanuric acid in S13 is (0.5~0.8) g : (80~100) mL : (2.5~3) mL : (0.5~0.8) g : (1~1.5) g. The mixture is heated to 40~50℃ and reacted for 3~4 h. It is then centrifuged and filtered at 6000~10000 rpm for 10~15 min, washed sequentially with acetonitrile and deionized water, and vacuum dried at 50~60℃.

[0018] Preferably, the method for preparing the toughening filler includes the following steps:

[0019] S21. Add montmorillonite to deionized water and crush it. Stir at high speed, let it stand to precipitate and take the supernatant. Add hexadecyltrimethylammonium chloride and heat to modify it. Collect the filter cake by suction filtration, dry it under vacuum and grind it to obtain modified montmorillonite.

[0020] S22. A toughening filler is prepared by mixing modified montmorillonite, fumed silica and cerium oxide.

[0021] Preferably, in S21, the mass ratio of montmorillonite to deionized water is 10~15:100, the mixture is stirred at a high speed of 3000~4000 rpm for 30~50 min, the mass ratio of the supernatant to hexadecyltrimethylammonium chloride is 100:2~4, the mixture is heated to 75~85℃ for 1~2 h for modification, and then vacuum dried at 100~110℃.

[0022] Preferably, in S22, the average particle size of fumed silica is 30-50 nm, the average particle size of cerium oxide is 300-500 nm, and the mass ratio of modified montmorillonite, fumed silica and cerium oxide is 3-5:6-8:0.5-1.

[0023] A method for preparing a high-torsion, low-smoke PVC / TPU composite cable material includes the following steps:

[0024] S1. Dry the raw materials to remove moisture and set aside;

[0025] S2. Add polyvinyl chloride resin, polyether thermoplastic polyurethane, and compatibilizer to a mixer and preheat and start mixing. Add flame retardant and smoke suppressant, maleic anhydride grafted ethylene-vinyl acetate copolymer, dioctyl phthalate plasticizer, heat stabilizer, antioxidant and dyeing carbon black, and heat and mix to obtain a mixture.

[0026] S3. The mixture is added to an extruder, heated and melted, and then extruded and cooled to obtain a high-torsion, low-smoke PVC / TPU composite cable material.

[0027] Preferably, in step S2, the temperature is preheated to 50-60°C and started to smelt for 5-15 minutes, and then mixed at 90-110°C for 5-10 minutes.

[0028] Preferably, the process in S3 involves heating to 170~190°C for melt extrusion.

[0029] An application of a high-torsion, low-smoke PVC / TPU composite cable material for use in the outer sheath of cables for charging guns and fans.

[0030] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0031] 1. This invention uses PVC and polyether-type TPU as the main components of cable material. The addition of compatibilizers improves the compatibility of PVC and polyether-type TPU, suppresses the problem of mechanical strength damage to cable material caused by phase separation, and has excellent low temperature resistance and water resistance, and can achieve low temperature torsion without damage.

[0032] 2. In this invention, aluminum phosphate is uniformly loaded onto the surface of nano-silica, and then a flame retardant and smoke suppressant is formed by polymerizing hexachlorocyclotriphosphazene with cyanuric acid. When heated, the outer organic part decomposes to produce non-flammable gas, which dilutes oxygen and flammable gas. The inner aluminum phosphate and silica decompose and absorb heat when heated, forming a dense and solid ceramic layer to block the diffusion of smoke and improve the flame retardant performance of the cable material.

[0033] 3. This invention enhances the dispersibility of montmorillonite in cable materials by modifying it with hexadecyltrimethylammonium chloride. Cerium oxide can absorb ultraviolet light to improve the antioxidant properties of the cable material. Fumed silica, cerium oxide, and modified montmorillonite form a multi-scale reinforcing network in the cable material. Fumed silica and cerium oxide can fill the gaps between the stacked montmorillonite sheets, making the entire filler system more compact. The nanosheet structure of modified montmorillonite can effectively block the penetration of water molecules and gases, improving the water resistance of the cable material. When the cable material is subjected to torsional deformation and microcracks are generated, the toughening filler prevents the rapid propagation of cracks, thereby improving the torsional resistance of the cable material and thus synergistically improving the mechanical strength of the cable material. Detailed Implementation

[0034] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0035] The polyvinyl chloride resin involved in this invention is designated as SG-5, the polyether-type thermoplastic polyurethane as 1175AW, the chlorinated polyethylene as 140C, the maleic anhydride-grafted ethylene-vinyl acetate copolymer as E226, the ethylene-vinyl acetate copolymer as VC590, the ethylene-ethyl acrylate copolymer as AC2116, and the ethylene-butyl acrylate copolymer as E2770.

[0036] Example 1: A high-torsion, low-smoke PVC / TPU composite cable material of this example comprises the following raw materials: 30g of polyvinyl chloride resin, 70g of polyether thermoplastic polyurethane, 10g of compatibilizer, 2g of chlorinated polyethylene, 1g of flame retardant and smoke suppressant, 10g of toughening filler, 3g of maleic anhydride-grafted ethylene-vinyl acetate copolymer, 2g of dioctyl phthalate plasticizer, 0.5g of heat stabilizer, 0.5g of antioxidant, and 10g of dyeing carbon black;

[0037] The compatibilizer is an ethylene-vinyl acetate copolymer;

[0038] The heat stabilizer is prepared by mixing zinc stearate and calcium stearate in a mass ratio of 3:1.

[0039] The antioxidant is prepared by mixing antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1.

[0040] The preparation method of the flame retardant and smoke suppressant in this embodiment includes the following steps:

[0041] S11. Add 3 mL of 25 wt% ammonia solution and 7 mL of deionized water to 70 mL of ethanol, slowly add 5 mL of tetraethyl orthosilicate, stir at 500 rpm for 50 min at 30 °C, filter to collect the solid, wash with deionized water, and dry at 60 °C to obtain nano-silica. Add 3 g of nano-silica to 100 mL of 50% ethanol solution, add 10 mL of KH-560, heat to 40 °C and stir at 300 rpm for 4 h to modify the reaction, filter to collect the solid, wash with deionized water, and dry at 60 °C to obtain modified nano-silica.

[0042] S12. Add 5g of modified nano-silica to 100g of 50% ethanol aqueous solution, then add 37wt% hydrochloric acid to adjust the pH to 2.5 to obtain dispersion A. Add 4.3g of phosphoric acid and 0.7g of aluminum hydroxide to 10g of deionized water and stir to dissolve to obtain solution B. Slowly add solution B dropwise to dispersion A and stir at 1000rpm for 30min. Add 25wt% ammonia aqueous solution to adjust the pH to 5 and age for 2h. Filter to collect the solid, wash with deionized water, and dry at 60℃ to obtain nano-template.

[0043] S13. Add 0.8g of hexachlorocyclotriphosphazene and 100mL of acetonitrile to a reaction vessel, add 2.5mL of triethanolamine var. acetonitrile, 0.8g of nanotemplate and 1g of cyanuric acid, heat to 50℃ and react for 4h, centrifuge at 6000rpm for 10min to collect the solid, wash with acetonitrile and deionized water in sequence, and dry under vacuum at 50℃ to obtain the flame retardant and smoke suppressant.

[0044] The method for preparing the toughening filler in this embodiment includes the following steps:

[0045] S21. Add 100g of montmorillonite to 1000g of deionized water and crush it. Stir at 3000rpm for 50min. After settling, take 100g of the supernatant, add 2g of hexadecyltrimethylammonium chloride and heat to 75℃ for 1h to modify it. Collect the filter cake by suction filtration, dry it under vacuum at 100℃, and grind it to obtain modified montmorillonite.

[0046] S22. A toughening filler is prepared by mixing 5g of modified montmorillonite, 8g of fumed silica with an average particle size of 30nm and 1g of cerium oxide with an average particle size of 400nm.

[0047] The preparation method of a high-torsion-resistance, low-smoke PVC / TPU composite cable material according to this embodiment includes the following steps:

[0048] S1. Dry the raw materials to remove moisture and set aside;

[0049] S2. Add polyvinyl chloride resin, polyether thermoplastic polyurethane, and compatibilizer to a mixer, heat to 60°C and start mixing for 5 minutes. Add flame retardant and smoke suppressant, maleic anhydride grafted ethylene-vinyl acetate copolymer, dioctyl phthalate plasticizer, heat stabilizer, antioxidant and dyeing carbon black, and mix at 110°C for 5 minutes to obtain a mixture.

[0050] S3. Add the mixture to an extruder, heat to 190°C, melt and extrude, and cool to obtain a high-torsion, low-smoke PVC / TPU composite cable material.

[0051] Example 2: A high-torsion, low-smoke PVC / TPU composite cable material of this example includes the following raw materials: 20g of polyvinyl chloride resin, 80g of polyether thermoplastic polyurethane, 13g of compatibilizer, 4g of chlorinated polyethylene, 1g of flame retardant and smoke suppressant, 3g of toughening filler, 3g of maleic anhydride-grafted ethylene-vinyl acetate copolymer, 5g of dioctyl phthalate plasticizer, 2g of heat stabilizer, 2g of antioxidant, and 5g of dyeing carbon black;

[0052] The compatibilizer is an ethylene-ethyl acrylate copolymer;

[0053] The heat stabilizer is prepared by mixing calcium acetylacetonate and zinc acetylacetonate in a mass ratio of 1:3.

[0054] The antioxidant is antioxidant 9012.

[0055] The preparation method of the flame retardant and smoke suppressant in this embodiment includes the following steps:

[0056] S11. Add 4 mL of 25 wt% ammonia solution and 9 mL of deionized water to 80 mL of ethanol, slowly add 7 mL of tetraethyl orthosilicate, stir at 800 rpm for 50 min at 40 °C, filter to collect the solid, wash with deionized water, and dry at 50 °C to obtain nano-silica. Add 4 g of nano-silica to 120 mL of 50% ethanol solution, add 12 mL of KH-560, heat to 60 °C and stir at 500 rpm for 6 h to modify the reaction, filter to collect the solid, wash with deionized water, and dry at 50 °C to obtain modified nano-silica.

[0057] S12. Add 8g of modified nano-silica to 100g of 50% ethanol aqueous solution, then add 37wt% hydrochloric acid to adjust the pH to 2.5 to obtain dispersion A. Add 4.1g of phosphoric acid and 0.5g of aluminum hydroxide to 10g of deionized water and stir to dissolve to obtain solution B. Slowly add solution B dropwise to dispersion A and stir at 1500rpm for 25min. Add 25wt% ammonia aqueous solution to adjust the pH to 6 and age for 2.5h. Filter to collect the solid, wash with deionized water, and dry at 50℃ to obtain nano-template.

[0058] S13. Add 0.7g of hexachlorocyclotriphosphazene and 90mL of acetonitrile to a reaction vessel, add 3mL of triethanolamine acid, 0.6g of nanotemplate and 1.3g of cyanuric acid, heat to 45℃ and react for 4h, centrifuge at 8000rpm for 10min to collect the solid, wash with acetonitrile and deionized water in sequence, and dry under vacuum at 60℃ to obtain the flame retardant and smoke suppressant.

[0059] The method for preparing the toughening filler in this embodiment includes the following steps:

[0060] S21. Add 150g of montmorillonite to 1000g of deionized water and crush it. Stir at 4000rpm for 40min. After settling, take 100g of the supernatant, add 3g of hexadecyltrimethylammonium chloride and heat to 85℃ for 2h to modify it. Collect the filter cake by suction filtration, dry it under vacuum at 110℃, and grind it to obtain modified montmorillonite.

[0061] S22. A toughening filler is prepared by mixing 5g of modified montmorillonite, 8g of fumed silica with an average particle size of 30nm and 0.8g of cerium oxide with an average particle size of 300nm.

[0062] The preparation method of a high-torsion-resistance, low-smoke PVC / TPU composite cable material according to this embodiment includes the following steps:

[0063] S1. Dry the raw materials to remove moisture and set aside;

[0064] S2. Add polyvinyl chloride resin, polyether thermoplastic polyurethane, and compatibilizer to a mixer and heat to 60°C for 10 minutes. Add flame retardant and smoke suppressant, maleic anhydride-grafted ethylene-vinyl acetate copolymer, dioctyl phthalate plasticizer, heat stabilizer, antioxidant and dyeing carbon black, and mix at 100°C for 8 minutes to obtain a mixture.

[0065] S3. Add the mixture to an extruder, heat to 180°C, melt and extrude, and cool to obtain a high-torsion, low-smoke PVC / TPU composite cable material.

[0066] Example 3: A high-torsion, low-smoke PVC / TPU composite cable material of this example includes the following raw materials: 25g of polyvinyl chloride resin, 75g of polyether thermoplastic polyurethane, 15g of compatibilizer, 6g of chlorinated polyethylene, 5g of flame retardant and smoke suppressant, 8g of toughening filler, 3g of maleic anhydride-grafted ethylene-vinyl acetate copolymer, 10g of dioctyl phthalate plasticizer, 1g of heat stabilizer, 1g of antioxidant, and 7g of dyeing carbon black;

[0067] The compatibilizer is an ethylene-butyl acrylate copolymer;

[0068] The heat stabilizer is prepared by mixing calcium stearate and zinc acetylacetonate in a mass ratio of 2:1.

[0069] The antioxidant is prepared by mixing antioxidant 1010 and antioxidant 9012 in a mass ratio of 1:1.

[0070] The preparation method of the flame retardant and smoke suppressant in this embodiment includes the following steps:

[0071] S11. Add 5 mL of 25 wt% ammonia solution and 10 mL of deionized water to 80 mL of ethanol, slowly add 7 mL of tetraethyl orthosilicate, stir at 800 rpm for 40 min at 35 °C, filter to collect the solid, wash with deionized water, and dry at 60 °C to obtain nano-silica. Add 6 g of nano-silica to 100 mL of 50% ethanol solution, add 10 mL of KH-560, heat to 50 °C and stir at 500 rpm for 5 h to modify the reaction, filter to collect the solid, wash with deionized water, and dry at 60 °C to obtain modified nano-silica.

[0072] S12. Add 6g of modified nano-silica to 100g of 50% ethanol aqueous solution, then add 37wt% hydrochloric acid to adjust the pH to 3 to obtain dispersion A. Add 4.5g of phosphoric acid and 0.5~0.8g of aluminum hydroxide to 10g of deionized water and stir to dissolve to obtain solution B. Slowly add solution B dropwise to dispersion A and stir at 1000~2000rpm for 20~30min. Add 25wt% ammonia aqueous solution to adjust the pH to 5~6.5 and age for 3h. Filter to collect the solid, wash with deionized water, and dry at 60℃ to obtain nano-template.

[0073] S13. Add 0.5g of hexachlorocyclotriphosphazene and 80mL of acetonitrile to a reaction vessel, add 2.7mL of triethanolamine acid, 0.5g of nanotemplate and 1.5g of cyanuric acid, heat to 40~50℃ and react for 3~4h, centrifuge at 10000rpm for 15min to collect the solid, wash with acetonitrile and deionized water in sequence, and dry under vacuum at 60℃ to obtain the flame retardant and smoke suppressant.

[0074] The method for preparing the toughening filler in this embodiment includes the following steps:

[0075] S21. Add 100-150g of montmorillonite to 1000g of deionized water and crush it. Stir at a high speed of 3000-4000rpm for 30-50min. After standing and settling, take 100g of the supernatant, add 4g of hexadecyltrimethylammonium chloride, heat to 75-85℃ and modify for 1-2h. Collect the filter cake by suction filtration, dry it under vacuum at 100-110℃, and grind it to obtain modified montmorillonite.

[0076] S22. A toughening filler is prepared by mixing 3-5g of modified montmorillonite, 6-8g of fumed silica with an average particle size of 30-50nm, and 0.5-1g of cerium oxide with an average particle size of 300-500nm.

[0077] The preparation method of a high-torsion-resistance, low-smoke PVC / TPU composite cable material according to this embodiment includes the following steps:

[0078] S1. Dry the raw materials to remove moisture and set aside;

[0079] S2. Add polyvinyl chloride resin, polyether thermoplastic polyurethane, and compatibilizer to a mixer and heat to 50°C for 15 minutes. Add flame retardant and smoke suppressant, maleic anhydride-grafted ethylene-vinyl acetate copolymer, dioctyl phthalate plasticizer, heat stabilizer, antioxidant and dyeing carbon black, and mix at 110°C for 10 minutes to obtain a mixture.

[0080] S3. Add the mixture to an extruder, heat to 170°C, melt and extrude, and cool to obtain a high-torsion, low-smoke PVC / TPU composite cable material.

[0081] Comparative Example 1 differs from Example 1 in that no compatibilizing agent is added.

[0082] Comparative Example 2 differs from Example 1 in that the flame retardant and smoke suppressant is replaced with melamine polyphosphate.

[0083] Comparative Example 3 differs from Example 1 in that the toughening filler is replaced with nano-alumina with an average particle size of 50 nm.

[0084] Performance testing

[0085] According to GB / T 1034-2008 "Determination of Water Absorption of Plastics", the cable materials prepared in each example and comparative example were cut into samples, vacuum dried at 80℃ for 24 hours, and the initial mass was recorded. The samples were then completely immersed in deionized water and soaked at room temperature for 48 hours. After removal and wiping off the surface moisture, the mass after water absorption was recorded. The water absorption rate was calculated according to the following formula:

[0086]

[0087] W represents the water absorption rate;

[0088] m1 is the initial mass, in grams;

[0089] m2 is the mass after water absorption, in grams.

[0090] Cable samples are prepared by extruding cable material and wrapping it around the surface of an aluminum alloy conductor.

[0091] According to the test examples and comparative examples of GB / T 33606-2017 "Twist-resistant flexible cables for wind power generation with rated voltage of 6kV (Um=7.2kV) to 35kV (Um=40.5kV)", 12.5m of cable samples were cut and subjected to 5000 cycles of torsion at -40℃ to check whether cracks appeared on the cable surface.

[0092] According to GB / T 19216.25-2003 "Line Integrity Tests for Cables and Optical Fibers under Flame Conditions - Part 25: Test Procedures and Requirements for Optical Fibers", the cable samples prepared in the examples and comparative examples were tested for power supply by burning in a flame at 830°C for 90 minutes under energized conditions.

[0093] The test results are shown in Table 1 below:

[0094] Table 1 Test Results

[0095] Test Project Water absorption rate (%) Low temperature torsional resistance Flame retardant properties Example 1 0.8 No cracks Power supply is normal Example 2 1.0 No cracks Power supply is normal Example 3 1.2 No cracks Power supply is normal Comparative Example 1 1.6 Cracks Power outage Comparative Example 2 1.4 No cracks Power outage Comparative Example 3 1.3 Cracks Power supply is normal

[0096] As shown in Table 1, the water absorption rate of the cable materials prepared in Examples 1-3 is 0.8-1.2%. The cable samples prepared in Examples 1-3 showed no cracks after 5000 cycles of torsion at -40℃, indicating that the cable materials prepared in this invention have excellent water resistance and low-temperature torsion resistance. The cable samples prepared in Examples 1-3 maintained normal power supply after burning in a flame at 830℃ for 90 minutes, indicating that the outer sheath made from the cable materials of this invention has excellent flame retardant properties.

[0097] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

[0098] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A high-torsion, low-smoke PVC / TPU composite cable material, characterized in that, The raw materials include the following parts by weight: 20-30 parts polyvinyl chloride resin, 70-80 parts polyether thermoplastic polyurethane, 10-15 parts compatibilizer, 2-6 parts chlorinated polyethylene, 1-5 parts flame retardant and smoke suppressant, 3-10 parts toughening filler, 1-3 parts maleic anhydride-grafted ethylene-vinyl acetate copolymer, 1-10 parts dioctyl phthalate plasticizer, 0.5-2 parts heat stabilizer, 0.5-2 parts antioxidant, and 1-10 parts coloring carbon black; The compatibilizer is one or more combinations of ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, and ethylene-butyl acrylate copolymer.

2. The high torsion resistance and low smoke emission PVC / TPU composite cable material according to claim 1, characterized in that, The heat stabilizer is one or more of zinc stearate, calcium stearate, calcium acetylacetonate and zinc acetylacetonate; The antioxidant is one or more of antioxidant 1010, antioxidant 168, and antioxidant 9012.

3. The high torsion resistance and low smoke emission PVC / TPU composite cable material according to claim 1, characterized in that, The preparation method of the flame retardant and smoke suppressant includes the following steps: S11. Add 25wt% ammonia solution and deionized water to ethanol, slowly add tetraethyl orthosilicate, stir the reaction, filter to collect the solid, wash and dry to obtain nano-silica. Add nano-silica to 50% ethanol solution, add KH-560, heat and stir to modify, filter to collect the solid, wash and dry to obtain modified nano-silica. S12. Modified nano-silica was added to a 50% ethanol aqueous solution, and hydrochloric acid was added to adjust the pH to obtain dispersion A. Phosphoric acid and aluminum hydroxide were added to deionized water to dissolve to obtain solution B. Solution B was slowly added dropwise to dispersion A and stirred to react. 25wt% ammonia aqueous solution was added dropwise for aging. The solid was collected by filtration, washed and dried to obtain nano-template. S13. Add hexachlorocyclotriphosphazene and acetonitrile to a reaction vessel, add triethanolamine acid, add nanotemplate and cyanuric acid, heat to react, centrifuge and filter to collect the solid, wash and vacuum dry to obtain flame retardant and smoke suppressant.

4. The high torsion resistance and low smoke emission PVC / TPU composite cable material according to claim 3, characterized in that, The volume ratio of 25wt% ammonia solution, deionized water, ethanol and tetraethyl orthosilicate in S11 is 3~5:7~10:70~80:5~7. The mixture is stirred at 30~40℃ and 500~1000rpm for 30~50min. The solid is collected by filtration, washed with deionized water, and dried at 50~60℃. The ratio of nano-silica, 50% ethanol solution and KH-560 is (1~3)g:(50~60)mL:(5~6)mL. The mixture is heated to 40~60℃ and stirred at 300~500rpm for 4~6h. The mixture is washed with deionized water and dried at 50~60℃.

5. The high torsion resistance and low smoke emission PVC / TPU composite cable material according to claim 3, characterized in that, In the S12 dispersion A, the mass ratio of modified nano-silica to 50% ethanol aqueous solution is 5~8:

100. Hydrochloric acid is added to adjust the pH to 2~3. In solution B, the mass ratio of phosphoric acid, aluminum hydroxide, and deionized water is 40~45:5~8:

100. The mass ratio of solution A to solution B is 10~15:

1. The reaction is stirred at 1000~2000 rpm for 20~30 min. 25wt% ammonia aqueous solution is added dropwise to adjust the pH to 5~6.

5. The mixture is aged for 2~3 h, washed with deionized water, and dried at 50~60℃.

6. The high torsion resistance and low smoke emission PVC / TPU composite cable material according to claim 3, characterized in that, The ratio of hexachlorocyclotriphosphazene, acetonitrile, triethanolamine, nanotemplate, and cyanuric acid in S13 is (0.5~0.8) g : (80~100) mL : (2.5~3) mL : (0.5~0.8) g : (1~1.5) g. The mixture is heated to 40~50℃ and reacted for 3~4 h. It is then centrifuged and filtered at 6000~10000 rpm for 10~15 min, washed sequentially with acetonitrile and deionized water, and dried under vacuum at 50~60℃.

7. The high torsion resistance and low smoke emission PVC / TPU composite cable material according to claim 1, characterized in that, The method for preparing the toughening filler includes the following steps: S21. Add montmorillonite to deionized water and crush it. Stir at high speed, let it stand to precipitate and take the supernatant. Add hexadecyltrimethylammonium chloride and heat to modify it. Collect the filter cake by suction filtration, dry it under vacuum and grind it to obtain modified montmorillonite. S22. A toughening filler is prepared by mixing modified montmorillonite, fumed silica and cerium oxide.

8. The high torsion resistance and low smoke emission PVC / TPU composite cable material according to claim 7, characterized in that, In S21, the mass ratio of montmorillonite to deionized water is 10~15:

100. The mixture is stirred at a high speed of 3000~4000 rpm for 30~50 min. The mass ratio of the supernatant to hexadecyltrimethylammonium chloride is 100:2~4. The mixture is heated to 75~85℃ for 1~2 h for modification and then vacuum dried at 100~110℃. In S22, the average particle size of fumed silica is 30~50 nm, the average particle size of cerium oxide is 300~500 nm, and the mass ratio of modified montmorillonite, fumed silica, and cerium oxide is 3~5:6~8:0.5~1.

9. A method for preparing a high-torsion, low-smoke PVC / TPU composite cable material, characterized in that, Includes the following steps: S1. Dry the raw materials to remove moisture and set aside; S2. Add polyvinyl chloride resin, polyether thermoplastic polyurethane, and compatibilizer to a mixer and preheat and start mixing. Add flame retardant and smoke suppressant, maleic anhydride grafted ethylene-vinyl acetate copolymer, dioctyl phthalate plasticizer, heat stabilizer, antioxidant and dyeing carbon black, and heat and mix to obtain a mixture. S3. The mixture is added to an extruder, heated and melted, and then extruded and cooled to obtain a high-torsion, low-smoke PVC / TPU composite cable material.

10. The method for preparing a high-torsion, low-smoke PVC / TPU composite cable material according to claim 9, characterized in that, In step S2, the temperature is preheated to 50-60℃ and started to be milled for 5-15 minutes, and then mixed at 90-110℃ for 5-10 minutes; in step S3, the temperature is heated to 170-190℃ and then melt-extruded.

Images