Lightweight airtight cable and processing method thereof

Abstract

The present application belongs to the technical field of light-weight cable, and particularly relates to a light-weight air-tight cable and a processing method thereof. The conductor of the present application adopts a tinned (bare) tight-press structure, but the load current remains unchanged, thereby reducing the overall outer diameter and overall weight of the cable. The cross-linking modified insulating polyolefin prepared by grafting a voltage stabilizer to polyethylene maintains the cross-linking degree of the cross-linking polyolefin while reducing the amount of cross-linking agent and inhibiting the migration of the voltage stabilizer, thereby improving the insulating performance of the insulating layer. The surface of the filling rope is modified by using an acetone solution of silicone rubber, so that the surface corrosion resistance and toughness of the filling rope are enhanced. The filling rope formed by blowing is not open net, and the stacking degree is more compact, thereby improving the air-tightness of the filling layer. The modified nano-magnesium hydroxide can decompose and absorb heat when the cable burns, and the flame retardant additive can catalyze the resin to form a carbon layer to block air, thereby having the performance of flame retardation and smoke suppression. The cable prepared by the present application has excellent air-tightness, insulation, fire resistance and flame retardation performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of lightweight cables, and in particular relates to a lightweight airtight cable and a processing method thereof. Background Art

[0002] Marine cables are a crucial component of a ship's electrical system, connecting key equipment such as generators, transformers, and switchboards. Ships experience vibrations and shocks during operation, and these mechanical stresses can damage cables. Therefore, cables must possess high mechanical strength to withstand the mechanical stresses of vibration, shock, and stretching during ship operation. Furthermore, cables must be lightweight to reduce the ship's load and improve its navigation efficiency and fuel economy. Cables are used in offshore floating production, storage, and offloading (FPSO) systems. When hazardous gases are present in unsafe areas, cables must be longitudinally airtight to prevent them from spreading from unsafe areas to safe areas through the cables.

[0003] Chinese invention patent publication number CN119181535B proposes a marine salt spray corrosion-resistant rubber-sheathed cable. The cable comprises, from the inside out, a conductor, a fire-resistant layer, an insulation layer, a flame-retardant layer, an armor layer, and a sheath layer. The sheath layer comprises the following components by weight: 100 parts EPDM rubber, 15-20 parts modifier-modified kaolin, 60-80 parts flame retardant, 1-3 parts antioxidant, 1-5 parts crosslinking agent, and 3-5 parts accelerator. The modifier-modified kaolin comprises a first modifier-modified kaolin and a second modifier-modified kaolin in a mass ratio of 1:9-9:1. The first modifier in the first modifier-modified kaolin is a silane coupling agent, and the second modifier in the second modifier-modified kaolin is an organic amine. This technical solution addresses the poor salt spray corrosion resistance of existing marine rubber-sheathed cables. The Chinese invention patent with publication number CN116230298B discloses a halogen-free flame-retardant lightweight ship cable, comprising a conductor, the conductor being externally wrapped with a low-smoke halogen-free sheath, the low-smoke halogen-free sheath being externally wrapped with a mica tape layer, the mica tape layer being externally wrapped with an armor layer, the armor layer being externally wrapped with a protective layer, the low-smoke halogen-free sheath being internally provided with a protective bracket, the protective bracket being fixedly mounted to the conductor. In this halogen-free flame-retardant lightweight ship cable and its low-smoke halogen-free sheath processing technology, the metal wire is externally wrapped with two layers of insulation made of different materials. The two layers cooperate to ensure the electrical performance of the cable and improve the flame retardancy of the cable. The mica tape layer provided can form a dense oxygen-isolating layer in the event of a fire, further improving the flame retardancy of the cable. The low-smoke halogen-free sheath used is lightweight and has excellent flame retardancy, effectively reducing the overall weight of the cable while providing excellent flame retardancy. However, the prior art has a technical problem of not further improving the composition of the insulating layer and the airtightness of the filler to enhance the insulation and airtightness of the cable. Summary of the Invention

[0004] The object of the present invention is to provide a lightweight airtight cable and a processing method thereof, so as to solve the technical problem in the prior art that the insulation and airtightness of the cable are not improved by further improving the airtightness of the composition of the insulating layer and the filler.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A lightweight, airtight cable comprising, from the inside out, a conductive core, an inner sheath, an armor layer, and an outer sheath. A ring array of 3 to 20 conductive cores is distributed within the inner sheath, and a filler is filled between the conductive core and the inner sheath.

[0007] The conductive core comprises a conductor, a fire-resistant layer and an insulating layer from the inside out. The outer diameter of the conductor is 9-14 mm, the outer diameter of the insulating layer is 1.1-1.5 mm, and the outer diameter of the conductive core is 11-16.5 mm.

[0008] Optionally, the conductive core further includes an insulating shielding layer and a metal shielding layer outside the insulating layer.

[0009] The insulating shielding layer material is a mixture of ethylene-ethyl acrylate resin and conductive carbon black, the added amount of conductive carbon black is 40-45% of the mass of the ethylene-ethyl acrylate resin, and the metal shielding layer material is copper foil.

[0010] The fire-resistant layer is a calcined mica tape; the insulating layer is a cross-linked modified insulating polyolefin; the filler is a non-open mesh filling rope with an outer diameter of 0.03 to 0.04 mm; the inner sheath layer is a low-smoke halogen-free flame-retardant polyolefin sheath, model SHF2; the armor layer is made of tinned copper wire; the outer sheath layer is a low-smoke halogen-free flame-retardant and oil-resistant cross-linked polyolefin material.

[0011] A method for processing a lightweight airtight cable comprises the following steps:

[0012] S1. Circular copper rods are drawn using a wire drawing machine. After annealing and tinning, qualified copper monofilaments are obtained through testing. The copper monofilaments are arranged and then twisted and compressed using a twisting machine using a compression die to produce a conductor.

[0013] S2, wrapping the mica tape around the conductor at a wrapping angle of 45 to 65 degrees to form a fire-resistant layer, and evenly coating the conductor with molten cross-linked modified insulating polyolefin through an extruder, and air-cooling and shaping to form a conductive core;

[0014] S3, twisting 3 to 20 single conductive cores into a cable, and filling with fillers in a spiral winding manner;

[0015] S4, the melted low-smoke halogen-free flame-retardant polyolefin sheath is uniformly coated on the periphery of the filler by an extruder, an inner sheath layer is prepared by air cooling and shaping, a braided layer is prepared by using tinned copper wire, the melted low-smoke halogen-free flame-retardant oil-resistant cross-linked polyolefin material is uniformly coated on the periphery of the braided layer by an extruder, an outer sheath layer is prepared by air cooling and shaping, and the light-weight airtight cable is obtained after the cable performance is detected and qualified and then packaged.

[0016] As preferred, the wire drawing die in S1 is selected from Z-shaped wire drawing die and circular wire drawing die, and the conductor is prepared by tightly pressing the Z-shaped copper single wire around the cylindrical copper single wire.

[0017] As preferred, the overlapping rate of the mica tape in S2 is between 30% and 40%.

[0018] As preferred, the braiding density of the braided layer in S4 is greater than 90%.

[0019] The preparation method of the cross-linked modified insulating polyolefin, comprising the following steps:

[0020] S11, according to mass parts, 0.2-0.3 parts of N, N-dimethyl-1, 2-ethylenediamine and 0.1-0.2 parts of cuprous iodide are added to 50-100 parts of deionized water, 3-5 parts of 3, 4'-dichlorobenzophenone is added to the system under stirring, nitrogen is introduced, the temperature is raised to 90-100℃, 2-3 parts of 4-methyl-3-pyrroline-2-ketone is added, and the condensation reaction is carried out at 100-105℃ for 24h, then activated carbon is added after filtration for dehydration for 10-12h, the product is separated by chromatography, and the grafting voltage stabilizer is obtained by rotary evaporation;

[0021] S12, according to mass parts, 95-100 parts of polyethylene resin, 1-2 parts of nano zinc oxide, 0.5-2 parts of antioxidant and 2-4 parts of grafting voltage stabilizer are added to a mixer and mixed for 5-10min, 0.5-2 parts of cross-linking agent is added, then the temperature is raised to 105-110℃ and stirred for 5-10min to prepare a cross-linked mixture, the cross-linked mixture is added to an extruder to extrude a hot melt, the hot melt is placed in a vulcanizing machine, the temperature is raised to 130-160℃, and the cross-linking is carried out at a pressure of 5-15Mpa for 20-40min, then the cross-linked product is cooled and placed in a vacuum environment at 70-80℃ for degassing to prepare the cross-linked modified insulating polyolefin.

[0022] As preferred, the synthesis principle of the grafting voltage stabilizer is as follows:

[0023]

[0024] The mass spectrum detection result of the grafting voltage stabilizer is as follows: m / z: 372.15 (100.0%), 373.15 (25.2%), 374.15 (3.8%).

[0025] As preferred, the cross-linking agent in S12 is any one of dicumyl peroxide, di-tert-butyl peroxide, 2,5 dimethyl-2,5-di(t-butylperoxy)hexane.

[0026] As preferred, the polyethylene resin in S12 is any one of 2426H, 19N430, HMA016, and the antioxidant is one or more combinations of 1010, 168, 1076.

[0027] As preferred, the feeding port temperature of the extruder in S12 is 110-120℃, and the discharging port temperature is 130-160℃.

[0028] The preparation method of the non-net filling rope comprises the following steps:

[0029] S21, by mass parts, 5-6 parts of nano zinc oxide powder is added into 50-60 parts of anhydrous ethanol, heated to 30-40℃, and 50-60 parts of a mixed solution of deionized water and anhydrous ethanol of vinyl silane coupling agent is added dropwise under stirring, after dropwise addition, reaction for 3-4h, heated to 70-80℃, 8-9 parts of acrylic acid, 1-2 parts of styrene, 1-1.5 parts of methyl acrylate, 1-2 parts of vinyl imidazole and 0.1-0.3 parts of azobisisobutyronitrile are added into 30-40 parts of anhydrous ethanol and added into the system, reacted at 70-80℃ for 4-6h, the solid is collected by suction filtration, washed with anhydrous ethanol, and dried at 70-80℃ to obtain modified nano zinc oxide powder;

[0030] S22, by mass parts, 95-100 parts of polypropylene, 5-6 parts of modified nano zinc oxide powder, 0.2-0.3 parts of nucleating agent and 0.5-2 parts of zinc stearate are mixed for 5-10min, added into the extruder to extrude to prepare a melt for blow molding, the melt is placed into a mold to extrude to prepare a hollow tube embryo, inflated and shaped, after cooling, immersed in a modified liquid for 1-2h, dried at room temperature for 12-24h, cut and rolled to prepare a non-net filling rope.

[0031] As preferred, the vinyl silane coupling agent in S21 is any one of A-151, A-152, A-173, the mass ratio of nano zinc oxide powder and vinyl silane coupling agent is 5-6:1-2, and the mass ratio of deionized water and anhydrous ethanol in the mixed solution of deionized water and anhydrous ethanol is 1:9.

[0032] Preferably, the model of the polypropylene resin in S22 is any one of HM550H, HM03, and F401, and the nucleating agent is prepared by mixing an α-type nucleating agent and a β-type nucleating agent in a mass ratio of 2 to 3:1, the α-type nucleating agent is any one of a sorbitol nucleating agent and a phosphate metal salt nucleating agent, and the β-type nucleating agent is any one of an aromatic amide nucleating agent and a rare earth nucleating agent.

[0033] Preferably, the extrusion rate of the melt for blow molding in S22 is 20-30 r / min, and the blow ratio of blow molding is 0.8-1.

[0034] Preferably, the modifying liquid in S22 is an acetone solution containing 5-8 wt% silicone rubber, and the silicone rubber is any one of KE-347 and SE 6035.

[0035] The preparation method of the low-smoke, halogen-free, flame-retardant, and oil-resistant cross-linked polyolefin material comprises the following steps:

[0036] S31. Add 5 to 6 parts of 4A zeolite powder to 500 to 1000 parts of deionized water by mass, ultrasonicate for 30 to 40 minutes, add 0.5 to 0.8 parts of copper chloride and 5 to 6 parts of dopamine hydrochloride, stir at a speed of 300 to 500 r / min for 10 to 20 minutes, then add 65 to 125 parts of tris(hydroxymethyl)aminomethane, adjust the pH to 8.5 with hydrochloric acid and ammonia water, stir at 30 to 40° C. for 10 to 12 hours, collect the solid by suction, wash with deionized water, and dry at 50 to 60° C. to prepare a flame retardant additive;

[0037] S32, by mass, 5 to 6 parts of nano magnesium hydroxide were added to 200 to 300 parts of anhydrous ethanol, ultrasonicated for 20 to 30 minutes to obtain a suspension, and then added to 200 to 300 parts of a 1 to 2 wt% carboxymethyl chitosan solution, stirred at a speed of 500 to 800 r / min and heated to 120 to 130 ° C., condensed and refluxed for 4 to 6 hours, and the solid was collected by centrifugation, washed with deionized water and anhydrous ethanol, and freeze-dried at 0 to 5 ° C. and ground to obtain modified nano magnesium hydroxide;

[0038] S33. Put 20-30 parts of polyethylene resin, 70-80 parts of ethylene vinyl acetate, 3-5 parts of polyolefin elastomer, 0.5-2 parts of dicumyl peroxide, 0.5-2 parts of zinc stearate and 0.5-2 parts of polyethylene wax into a mixer, crosslink at a speed of 1000-2000 r / min for 5-10 minutes, then add 3-5 parts of modified nano magnesium hydroxide, 1-3 parts of flame retardant additives and 1-2 parts of antioxidant, mix at a speed of 2000-3000 r / min for 5-10 minutes to prepare a mixture, put the mixture into an open mill, mix and roll at 100-110°C for 5-10 minutes, then add it into a vacuum vulcanizer, heat to 120-150°C, crosslink at a pressure of 8-10 MPa for 10-20 minutes to prepare a low-smoke, halogen-free, flame-retardant and oil-resistant cross-linked polyolefin material.

[0039] Preferably, the model of the polyethylene resin in S33 is any one of 2426H, 19N430, and HMA016, the model of ethylene vinyl acetate is any one of 7470M, EV180, and EV210ETR, the polyolefin elastomer is any one of C1070D, E226, and C5070D, and the antioxidant is one or more combinations of 1010, 168, and 1076.

[0040] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0041] 1. The conductor of the present invention adopts a tinned (bare) compact structure, the number of conductors is reduced, the outer diameter of the conductor is reduced, but the current carrying capacity remains unchanged, the overall outer diameter and overall weight of the cable are reduced, and the cable can be used in a narrow laying environment to improve space utilization; the cross-linked modified insulating polyolefin prepared by grafting a voltage stabilizer onto polyethylene maintains the cross-linking degree of the cross-linked polyolefin while reducing the amount of the cross-linking agent, and inhibiting the migration of the voltage stabilizer, thereby improving the insulation performance of the insulating layer; polypropylene and modified zinc oxide are prepared by a blowing process to prepare a filling rope, and then the filling rope is slurried with an acetone solution of silicone rubber. The surface modification of the rope enhances the surface corrosion resistance and toughness of the filling rope. The filling rope formed by blowing does not open the mesh and is stacked more tightly, thereby improving the air tightness of the filling layer. The low-smoke, halogen-free, flame-retardant, and oil-resistant cross-linked polyolefin material prepared from polyethylene resin, ethylene-vinyl acetate, polyolefin elastomer, modified nano-magnesium hydroxide, and flame retardant additives has excellent oil-resistance and flame retardant properties. When the cable burns, the modified nano-magnesium hydroxide can decompose and absorb heat, and the flame retardant additive can catalyze the resin to form a carbon layer to block air, thereby having flame retardant and smoke suppression properties. The cable prepared by the present invention has excellent air tightness, insulation, fire resistance, and flame retardant properties.

[0042] 2. The grafted voltage stabilizer obtained by the grafting reaction of 3,4'-dichlorobenzophenone and 4-methyl-3-pyrroline-2-one has a benzophenone structure, which can absorb high-energy electrons. The conjugated aromatic ring structure can uniformly distribute the electric field and inhibit partial discharge. The grafted voltage stabilizer is cross-linked and grafted onto polyethylene to improve the stabilizer's migration resistance. The obtained cross-linked modified insulating polyolefin has excellent voltage stability.

[0043] 3. The modified nano-zinc oxide powder prepared by grafting nano-zinc oxide with a vinyl silane coupling agent and then grafting acrylic acid, styrene, methyl acrylate and vinyl imidazole has excellent antioxidant properties and dispersibility; the cyclic structures contained in the grafted styrene and vinyl imidazole improve the wear resistance of the polypropylene filling rope; the surface of the filling rope is modified by an acetone solution of silicone rubber to enhance the surface corrosion resistance and toughness of the filling rope, thereby improving the tensile strength and antioxidant properties of the polypropylene filling rope.

[0044] 4. The low-smoke, halogen-free, flame-retardant and oil-resistant cross-linked polyolefin material prepared from polyethylene resin, ethylene-vinyl acetate, polyolefin elastomer, modified nano-magnesium hydroxide and flame retardant additives has excellent oil resistance and flame retardant properties. The cross-linked polyolefin prepared from polyethylene resin, ethylene-vinyl acetate and polyolefin elastomer has excellent oil resistance; when the cable burns, the modified nano-magnesium hydroxide can decompose and absorb heat, and the flame retardant additive can catalyze the resin to form a carbon layer to block the air, and has fire resistance and flame retardant and smoke suppression properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0046] Figure 1 It is a cross-sectional schematic diagram of a lightweight airtight cable of the present invention;

[0047] Figure 2 is a cross-sectional schematic diagram of another lightweight airtight cable of the present invention;

[0048] Figure 3 This is a schematic diagram of a first conductor structure of a lightweight airtight cable of the present invention;

[0049] Figure 4 This is a schematic diagram of a second conductor structure of a lightweight airtight cable of the present invention;

[0050] Figure 5 This is a schematic diagram of a third conductor structure of a lightweight airtight cable of the present invention;

[0051] Figure 6 This is a first physical diagram of a lightweight airtight cable of the present invention;

[0052] Figure 7 This is a second physical picture of a lightweight airtight cable of the present invention.

[0053] Reference numerals: 1-1 conductor, 1-2 fire-resistant layer, 1-3 insulation layer, 1-4 insulation shielding layer, 1-5 metal shielding layer, 1 conductive core, 2 filler, 3 inner sheath layer, 4 armor layer and 5 outer sheath layer. DETAILED DESCRIPTION

[0054] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0055] Example 1, see Figure 1 、 Figure 6 As shown, a lightweight airtight cable of this embodiment includes, from the inside out, a conductive core 1, an inner sheath layer 3, an armor layer 4, and an outer sheath layer 5. 19 conductive cores are arranged in a circular array around the inner sheath layer, and a filler 2 is filled between the conductive core and the inner sheath layer.

[0056] The conductive core comprises a conductor 1-1, a fire-resistant layer 1-2 and an insulating layer 1-3 from the inside out. The outer diameter of the conductor is 9 mm, the insulating layer is 1.1 mm, and the outer diameter of the conductive core is 11.5 mm.

[0057] The fire-resistant layer is a calcined mica tape; the insulating layer is a cross-linked modified insulating polyolefin; the filler is a non-open mesh filling rope with an outer diameter of 0.04 mm; the inner sheath layer is a low-smoke halogen-free flame-retardant polyolefin sheath, model SHF2; the armor layer is made of tinned copper wire; the outer sheath layer is a low-smoke halogen-free flame-retardant and oil-resistant cross-linked polyolefin material.

[0058] Example 2, see Figure 2 、 Figure 7 As shown, a lightweight airtight cable of this embodiment differs from that of embodiment 1 in that, from the inside out, it comprises a conductive core 1, an inner sheath layer 3, an armor layer 4, and an outer sheath layer 5, three conductive cores are arranged in a circular array around the inner sheath layer, and a filler 2 is filled between the conductive core and the inner sheath layer;

[0059] The conductive core comprises a conductor 1-1, a fire-resistant layer 1-2, an insulating layer 1-3, an insulating shielding layer 1-4 and a metal shielding layer 1-5 from the inside out. The outer diameter of the conductor is 11 mm, the insulating layer is 1.1 mm, and the outer diameter of the conductive core is 13.2 mm.

[0060] The insulating shielding layer material is a mixture of ethylene-ethyl acrylate resin and conductive carbon black, the added amount of conductive carbon black is 40% of the total weight of the ethylene-ethyl acrylate resin, and the metal shielding layer material is copper foil.

[0061] The fire-resistant layer is a calcined mica tape; the insulating layer is a cross-linked modified insulating polyolefin; the filler is a non-open mesh filling rope with an outer diameter of 0.03 mm; the inner sheath layer is a low-smoke halogen-free flame-retardant polyolefin sheath, model SHF2; the armor layer is made of tinned copper wire; the outer sheath layer is a low-smoke halogen-free flame-retardant and oil-resistant cross-linked polyolefin material.

[0062] Example 3: A method for processing a lightweight airtight cable according to this embodiment includes the following steps:

[0063] S1. Circular copper rods are drawn using a wire drawing machine. After annealing and tinning, qualified copper monofilaments are obtained through testing. The copper monofilaments are arranged and then twisted and compressed using a twisting machine using a compression die to produce a conductor.

[0064] S2. Wrapping a mica tape around a conductor at a wrapping angle of 45° to form a fire-resistant layer, with an overlap ratio of 35%; extruding molten cross-linked modified insulating polyolefin through an extruder; uniformly coating the conductor with the molten cross-linked modified insulating polyolefin; and air-cooling and shaping the conductor to form a conductive core;

[0065] S3, twisting 19 single conductive cores into a cable, and filling with fillers in a spiral winding manner;

[0066] S4. The molten low-smoke, halogen-free, flame-retardant polyolefin sheath is evenly coated on the periphery of the filler through an extruder, and air-cooled and shaped to obtain an inner sheath layer. Tinned copper wire is used to weave an armor layer with a weaving density greater than 90%. The molten low-smoke, halogen-free, flame-retardant, and oil-resistant cross-linked polyolefin material is evenly coated on the periphery of the armor layer through an extruder, and air-cooled and shaped to obtain an outer sheath layer. After the cable performance is tested and found to be qualified, it is packaged and shipped out to obtain a lightweight airtight cable.

[0067] The preparation method of the cross-linked modified insulating polyolefin of this embodiment comprises the following steps:

[0068] S11. Add 2 g of N,N-dimethyl-1,2-ethylenediamine and 1 g of cuprous iodide to 500 g of deionized water by mass, add 20 g of 3,4'-dichlorobenzophenone to the system while stirring, introduce nitrogen, raise the temperature to 100°C, add 10 g of 4-methyl-3-pyrrolidone-2-one, and condense the mixture at 105°C for 24 h. After filtering, add activated carbon for dehydration for 12 h, separate the product by chromatography, and rotary evaporate to obtain a grafted voltage stabilizer;

[0069] S12. According to mass, add 950g of 2426H polyethylene resin, 10g of nano zinc oxide, 10g of 1010 antioxidant and 20g of grafted voltage stabilizer into a mixer and mix for 10 minutes. After adding 20g of diisopropylbenzene peroxide cross-linking agent, heat up to 110°C and stir and cross-link for 10 minutes to obtain a cross-linked mixture. Add the cross-linked mixture into an extruder and extrude to obtain a hot melt. The feed port temperature of the extruder is 110°C, and the discharge port temperature is 130°C. Put the hot melt into a vulcanizer, heat up to 130°C, and hot-press and cross-link at a pressure of 10Mpa for 20 minutes. After cooling, put it into a vacuum environment at 80°C for degassing to obtain a cross-linked modified insulating polyolefin.

[0070] The method for preparing the non-opening filling rope of this embodiment comprises the following steps:

[0071] S21. By mass, 5 g of nano zinc oxide powder was added to 50 g of anhydrous ethanol, and the temperature was raised to 30°C. 50 g of a mixed solution prepared by dissolving 1 g of A-151 vinyl silane coupling agent in deionized water and anhydrous ethanol at a mass ratio of 1:9 was added dropwise under stirring. After the addition was complete, the mixture was reacted for 4 h. The temperature was raised to 80°C. 8 g of acrylic acid, 1 g of styrene, 1.5 g of methyl acrylate, 2 g of vinylimidazole and 0.3 g of azobisisobutyronitrile were added to 40 g of anhydrous ethanol and then added to the system. The mixture was reacted at 80°C for 4 h. The solid was collected by filtration, washed with anhydrous ethanol, and dried at 70°C to obtain modified nano zinc oxide powder.

[0072] S22. According to mass, 960g of F401 polypropylene, 50g of modified nano zinc oxide powder, 3g of nucleating agent and 5g of zinc stearate are mixed for 5 minutes. The nucleating agent is prepared by mixing NA-88 sorbitol α-type nucleating agent and WBG-Ⅱ rare earth β-type nucleating agent in a mass ratio of 2:1. The mixture is added to an extruder and extruded at an extrusion rate of 25r / min to obtain a melt for blow molding. The melt is placed in a mold and extruded to obtain a hollow tube embryo. The tube is blown to shape with a blowing ratio of 1. After cooling, it is immersed in a modifying liquid for 2h. The modifying liquid is an acetone solution containing 5wt% KE-347 silicone rubber. The tube is dried at room temperature for 24h, cut and rolled to obtain a non-open mesh filling rope.

[0073] The preparation method of the low-smoke, halogen-free, flame-retardant, and oil-resistant cross-linked polyolefin material of this embodiment comprises the following steps:

[0074] S31. Add 5 g of 4A zeolite powder to 500 g of deionized water by mass, ultrasonicate for 30 min, add 0.5 g of copper chloride and 5 g of dopamine hydrochloride, stir at 500 r / min for 20 min, add 65 g of tris(hydroxymethyl)aminomethane, adjust the pH to 8.5 with hydrochloric acid and ammonia water, stir at 40°C for 12 h, collect the solid by filtration, wash with deionized water, and dry at 60°C to obtain a flame retardant additive;

[0075] S32, by mass, 5.5g of nano magnesium hydroxide was added to 200g of anhydrous ethanol, ultrasonicated for 20min to obtain a suspension, and then added to 200g of 1wt% carboxymethyl chitosan solution, stirred at a speed of 500r / min and heated to 120°C for 6h, condensed and refluxed, and the solid was collected by centrifugation, washed with deionized water and anhydrous ethanol, and freeze-dried at 0°C. The modified nano magnesium hydroxide was ground;

[0076] S33. According to mass, 200g of 2426H polyethylene resin, 800g of 7470M ethylene vinyl acetate, 30g of C1070D polyolefin elastomer, 5g of dicumyl peroxide, 5g of zinc stearate and 10g of polyethylene wax are put into a mixer, cross-linked at a speed of 1000r / min for 5min, and then 30g of modified nano magnesium hydroxide, 15g of flame retardant additive and 15g of 1010 antioxidant are added and mixed at a speed of 2000r / min for 5min to obtain a mixture. The mixture is put into an open mill, mixed and rolled at 110°C for 10min, and then added into a vacuum vulcanizer, heated to 120°C, and cross-linked at a pressure of 10MPa for 20min to obtain a low-smoke, halogen-free, flame-retardant and oil-resistant cross-linked polyolefin material.

[0077] Example 4: A method for processing a lightweight airtight cable according to this embodiment includes the following steps:

[0078] S1. Circular copper rods are drawn using a wire drawing machine. After annealing and tinning, qualified copper monofilaments are obtained through testing. The copper monofilaments are arranged and then twisted and compressed using a twisting machine using a compression die to produce a conductor.

[0079] S2. Wrapping a mica tape around a conductor at a wrapping angle of 50° to form a fire-resistant layer, with a wrapping overlap ratio of 40%, extruding molten cross-linked modified insulating polyolefin through an extruder, and evenly coating the conductor with the molten cross-linked modified insulating polyolefin, followed by air cooling and shaping to form a conductive core;

[0080] S3, twisting three single conductive cores into a cable, and filling with fillers in a spiral winding manner;

[0081] S4. The molten low-smoke, halogen-free, flame-retardant polyolefin sheath is evenly coated on the periphery of the filler through an extruder, and air-cooled and shaped to obtain an inner sheath layer. Tinned copper wire is used to weave an armor layer with a weaving density greater than 90%. The molten low-smoke, halogen-free, flame-retardant, and oil-resistant cross-linked polyolefin material is evenly coated on the periphery of the armor layer through an extruder, and air-cooled and shaped to obtain an outer sheath layer. After the cable performance is tested and found to be qualified, it is packaged and shipped out to obtain a lightweight airtight cable.

[0082] The cross-linked modified insulating polyolefin of this embodiment differs from that of embodiment 3 in that the model of the polyethylene resin is replaced by HMA016, and the oxidant is replaced by 1010 and 168 mixed in a mass ratio of 1:1.

[0083] The preparation methods of the non-open mesh filling rope and the low-smoke, halogen-free, flame-retardant, and oil-resistant cross-linked polyolefin material of this embodiment are the same as those of Example 3.

[0084] Example 5: A method for processing a lightweight airtight cable according to this embodiment includes the following steps:

[0085] S1. Circular copper rods are drawn using a wire drawing machine. After annealing and tinning, qualified copper monofilaments are obtained through testing. The copper monofilaments are arranged and then twisted and compressed using a twisting machine using a compression die to produce a conductor.

[0086] S2. Wrapping a mica tape around a conductor at a wrapping angle of 60° to form a fire-resistant layer, with an overlap ratio of 33%; extruding molten cross-linked modified insulating polyolefin through an extruder; uniformly coating the conductor with the molten cross-linked modified insulating polyolefin; and air-cooling and shaping the conductor to form a conductive core;

[0087] S3, twisting 19 single conductive cores into a cable, and filling with fillers in a spiral winding manner;

[0088] S4. The molten low-smoke, halogen-free, flame-retardant polyolefin sheath is evenly coated on the periphery of the filler through an extruder, and air-cooled and shaped to obtain an inner sheath layer. Tinned copper wire is used to weave an armor layer with a weaving density greater than 90%. The molten low-smoke, halogen-free, flame-retardant, and oil-resistant cross-linked polyolefin material is evenly coated on the periphery of the armor layer through an extruder, and air-cooled and shaped to obtain an outer sheath layer. After the cable performance is tested and found to be qualified, it is packaged and shipped out to obtain a lightweight airtight cable.

[0089] The difference between the non-open mesh filling rope of this embodiment and that of embodiment 3 is that the nucleating agent is prepared by mixing NA-21 phosphate metal salt nucleating agent and TMB-5 aromatic amide nucleating agent in a mass ratio of 2:1.

[0090] The preparation method of the cross-linked modified insulating polyolefin and the low-smoke halogen-free flame-retardant and oil-resistant cross-linked polyolefin material in this embodiment is the same as that in Example 3.

[0091] Example 6: A method for processing a lightweight airtight cable according to this embodiment includes the following steps:

[0092] S1. Circular copper rods are drawn using a wire drawing machine. After annealing and tinning, qualified copper monofilaments are obtained through testing. The copper monofilaments are arranged and then twisted and compressed using a twisting machine using a compression die to produce a conductor.

[0093] S2. Wrapping a mica tape around a conductor at a wrapping angle of 65° to form a fire-resistant layer, with a double-layer overlap ratio of 30%; extruding molten cross-linked modified insulating polyolefin through an extruder; uniformly coating the conductor with the molten cross-linked modified insulating polyolefin; and air-cooling and shaping the conductor to form a conductive core;

[0094] S3, twisting 20 single conductive cores into a cable, and filling with fillers in a spiral winding manner;

[0095] S4. The molten low-smoke, halogen-free, flame-retardant polyolefin sheath is evenly coated on the periphery of the filler through an extruder, and air-cooled and shaped to obtain an inner sheath layer. Tinned copper wire is used to weave an armor layer with a weaving density greater than 90%. The molten low-smoke, halogen-free, flame-retardant, and oil-resistant cross-linked polyolefin material is evenly coated on the periphery of the armor layer through an extruder, and air-cooled and shaped to obtain an outer sheath layer. After the cable performance is tested and found to be qualified, it is packaged and shipped out to obtain a lightweight airtight cable.

[0096] The low-smoke, halogen-free, flame-retardant, and oil-resistant cross-linked polyolefin material of this embodiment differs from that of Example 3 in that the model of the polyethylene resin is replaced by 19N430, and the model of the ethylene vinyl acetate is replaced by EV180.

[0097] The cross-linked modified insulating polyolefin and the non-open mesh filling rope of this embodiment are prepared in the same manner as in Example 3.

[0098] Comparative Example 1: This comparative example differs from Example 3 in that the grafted voltage stabilizer of the cross-linked modified insulating polyolefin is replaced with 4,4'-dihydroxybenzil.

[0099] Comparative Example 2: The difference between this comparative example and Example 3 is that the non-open-net filling rope is replaced by an open-net filling rope.

[0100] Comparative Example 3: The difference between this comparative example and Example 3 is that the low-smoke, halogen-free, flame-retardant, and oil-resistant cross-linked polyolefin material is replaced by a cross-linked polyethylene material.

[0101] Performance Testing

[0102] The conductors obtained in Example 3 and conventional conductor structures are shown in FIG. Figure 3-5 As shown, the conductor outer diameter, insulation layer thickness and approximate outer diameter of the conductor prepared in Example 3 and the conventional conductor were tested. The test results are shown in Table 1:

[0103] Table 1 Conductor structure

[0104]

[0105]

[0106] According to IEC60079-14 standard, 0.5 m of the lightweight airtight cables prepared in Examples 3 to 6 and Comparative Examples 1 to 3 were cut, compressed air exceeding atmospheric pressure by 0.3 kPa was applied to one end, and the rate of decrease of the overpressure value within 5 s was measured.

[0107] According to the IEC60331 standard, as shown in Table 2 below, the lightweight airtight cables prepared in Examples 3 to 6 and Comparative Examples 1 to 3 were tested for fuse blowing within 120 minutes (accumulated 36 times of impact vibration) under 830°C flame burning and impact vibration (impact vibration interval does not exceed 5 minutes).

[0108] Table 2 IEC60331 standard

[0109]

[0110] According to IEC60092-350 standard, the lightweight airtight cables prepared in Examples 3 to 6 and Comparative Examples 1 to 3 were aged at 100° C. for 24 h using IRM902 mineral oil and IRM903 fuel oil, and the change rates of tensile strength and elongation at break were tested.

[0111] The test results are shown in Table 3 below:

[0112] Table 3 Test results

[0113]

[0114]

[0115] It can be seen from the data in Table 1 that the outer diameter and approximate outer diameter of the conductor in Example 3 are both smaller than those of conventional conductors, indicating that the lightweight airtight cable produced by the present invention reduces the overall outer diameter of the cable and can improve space utilization.

[0116] It can be seen from the data in Table 2 that the overvoltage value reduction rate of the lightweight airtight cables of Examples 3 to 6 of the present invention is between 13% and 16%. The non-open mesh filling rope of Comparative Example 2 is replaced by an open mesh filling rope, which leads to a decrease in the airtightness of the filler. Therefore, its overvoltage value reduction rate is 28%, which is much larger than the overvoltage value reduction rate of Examples 3 to 6, indicating that the lightweight airtight cable prepared by the present invention has excellent airtightness; the electrical conductivity of Examples 3 to 6 is good under 830°C flame burning and impact vibration (the impact vibration interval does not exceed 5 minutes), and the fuse does not melt within 120 minutes (accumulated impact vibration 36 times), indicating that the lightweight airtight cable prepared by the present invention has excellent fire resistance, flame retardant and insulation properties; after aging treatment, the tensile strength change rate of the lightweight airtight cables of Examples 3 to 6 of the present invention is 17-20%, and the elongation at break change rate is 20-22%, indicating that the lightweight airtight cable prepared by the present invention has excellent anti-oil performance.

[0117] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

[0118] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to specific embodiments. Obviously, many modifications and variations are possible based on the contents of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A lightweight airtight cable, characterized in that: From the inside out, it includes a conductive core, an inner sheath layer, an armor layer, and an outer sheath layer. Multiple conductive cores are distributed in a circular array around the inner sheath layer, and fillers are filled between the conductive core and the inner sheath layer. The conductive core comprises a conductor, a fire-resistant layer and an insulating layer from the inside out, the outer diameter of the conductor is 9-14 mm, the outer diameter of the insulating layer is 1.1-1.5 mm, and the outer diameter of the conductive core is 11-16.5 mm; The conductive core also includes an insulating shielding layer and a metal shielding layer outside the insulating layer. The insulating shielding layer material is a mixture of ethylene-ethyl acrylate resin and conductive carbon black, and the conductive carbon black addition amount is 40-45% of the mass of the ethylene-ethyl acrylate resin. The metal shielding layer material is copper foil; the fire-resistant layer is calcined mica tape; the insulating layer is cross-linked modified insulating polyolefin; the filler is a non-open mesh filling rope with an outer diameter of 0.03-0.04mm; the inner sheath layer is a low-smoke halogen-free flame-retardant polyolefin sheath; the armor layer is woven from tinned copper wire; the outer sheath layer is a low-smoke halogen-free flame-retardant and oil-resistant cross-linked polyolefin material; The method for preparing the insulating layer material of the cross-linked modified insulating polyolefin comprises the following steps: S11. Add 0.2-0.3 parts of N,N-dimethyl-1,2-ethylenediamine and 0.1-0.2 parts of cuprous iodide to 50-100 parts of deionized water, add 3-5 parts of 3,4'-dichlorobenzophenone to the system under stirring, introduce nitrogen, raise the temperature to 90-100°C, add 2-3 parts of 4-methyl-3-pyrrolidone, and condense the reaction at 100-105°C for 24 hours. After filtering, add activated carbon for dehydration for 10-12 hours, separate the product by chromatography, and rotary evaporate to obtain a graft voltage stabilizer; S12. Add 95-100 parts of polyethylene resin, 1-2 parts of nano zinc oxide, 0.5-2 parts of antioxidant and 2-4 parts of grafted voltage stabilizer into a mixer and mix for 5-10 minutes. After adding 0.5-2 parts of a cross-linking agent, heat up to 105-110°C and stir and cross-link for 5-10 minutes to obtain a cross-linked mixture. Add the cross-linked mixture into an extruder and extrude to obtain a hot melt. Put the hot melt into a vulcanizer, heat up to 130-160°C, and hot-press and cross-link at a pressure of 5-15 MPa for 20-40 minutes. After cooling, put it into a vacuum environment of 70-80°C for degassing to obtain a cross-linked modified insulating polyolefin.

2. A lightweight airtight cable according to claim 1, characterized in that: The crosslinking agent in S12 is any one of diisopropylbenzene peroxide, di-tert-butyl peroxide, and 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane; the antioxidant is one or more combinations of 1010, 168, and 1076; the feed port temperature of the extruder is 110-120°C, and the discharge port temperature is 130-160°C.

3. A lightweight airtight cable according to claim 1, characterized in that: The method for preparing the non-opening mesh filling rope comprises the following steps: S21. Add 5 to 6 parts of nano zinc oxide powder to 50 to 60 parts of anhydrous ethanol by mass, raise the temperature to 30 to 40° C., add 50 to 60 parts of a mixed solution of deionized water and anhydrous ethanol of a vinyl silane coupling agent dropwise under stirring, react for 3 to 4 hours after the addition is complete, raise the temperature to 70 to 80° C., add 8 to 9 parts of acrylic acid, 1 to 2 parts of styrene, 1 to 1.5 parts of methyl acrylate, 1 to 2 parts of vinylimidazole and 0.1 to 0.3 parts of azobisisobutyronitrile to 30 to 40 parts of anhydrous ethanol and then add the mixture to the system, react at 70 to 80° C. for 4 to 6 hours, collect the solid by suction, wash with anhydrous ethanol, and dry at 70 to 80° C. to obtain modified nano zinc oxide powder; S22. Mix 95-100 parts of polypropylene, 5-6 parts of modified nano zinc oxide powder, 0.2-0.3 parts of nucleating agent and 0.5-2 parts of zinc stearate by mass for 5-10 minutes, add the mixture into an extruder and extrude to obtain a melt for blow molding, put the melt into a mold and extrude to obtain a hollow tube embryo, blow and shape it, soak it in a modifying liquid for 1-2 hours after cooling, dry it at room temperature for 12-24 hours, cut it into pieces and roll it up to obtain a non-open mesh filling rope.

4. A lightweight airtight cable according to claim 3, characterized in that: The mass ratio of nano zinc oxide powder and vinyl silane coupling agent in S21 is 5-6:1-2, and the mass ratio of deionized water and anhydrous ethanol in the mixed solution of deionized water and anhydrous ethanol is 1:9; the nucleating agent in S22 is prepared by mixing an α-type nucleating agent and a β-type nucleating agent in a mass ratio of 2-3:1, the α-type nucleating agent is any one of a sorbitol nucleating agent and a phosphate metal salt nucleating agent, and the β-type nucleating agent is any one of an aromatic amide nucleating agent and a rare earth nucleating agent. The extrusion rate of the melt for blow molding is 20-30 r / min, the blow ratio of blow molding is 0.8-1, and the modifying liquid is an acetone solution containing 5-8wt% silicone rubber.

5. The lightweight airtight cable according to claim 1, characterized in that: The preparation method of the low-smoke, halogen-free, flame-retardant, and oil-resistant cross-linked polyolefin material comprises the following steps: S31. Add 5 to 6 parts of 4A zeolite powder to 500 to 1000 parts of deionized water, ultrasonically treat for 30 to 40 minutes, add 0.5 to 0.8 parts of copper chloride and 5 to 6 parts of dopamine hydrochloride, stir at a speed of 300 to 500 r / min for 10 to 20 minutes, then add 65 to 125 parts of tris (hydroxymethyl)aminomethane, adjust the pH to 8.5 with hydrochloric acid and ammonia water, stir at 30 to 40°C for 10 to 12 hours, collect the solid by suction, wash with deionized water, and dry at 50 to 60°C to prepare a flame retardant additive; S32, by mass, 5 to 6 parts of nano magnesium hydroxide were added to 200 to 300 parts of anhydrous ethanol, and then added to 200 to 300 parts of 1 to 2 wt% carboxymethyl chitosan solution after ultrasonication for 20 to 30 minutes. The mixture was stirred at a speed of 500 to 800 r / min and heated to 120 to 130 ° C. and refluxed for 4 to 6 hours. The solid was collected by centrifugation, washed with deionized water and anhydrous ethanol, and then freeze-dried at 0 to 5 ° C. and ground to obtain modified nano magnesium hydroxide; S33. Put 20-30 parts of polyethylene resin, 70-80 parts of ethylene vinyl acetate, 3-5 parts of polyolefin elastomer, 0.5-2 parts of diisopropyl benzene peroxide, 0.5-2 parts of zinc stearate and 0.5-2 parts of polyethylene wax into a mixer, crosslink for 5-10 minutes, then add 3-5 parts of modified nano magnesium hydroxide, 1-3 parts of flame retardant additive and 1-2 parts of antioxidant, mix for 5-10 minutes to prepare a mixture, put the mixture into an open mill, mix and roll at 100-110°C for 5-10 minutes, then add it into a vacuum vulcanizer, heat to 120-150°C, crosslink at a pressure of 8-10 MPa for 10-20 minutes to prepare a low-smoke, halogen-free, flame-retardant and oil-resistant cross-linked polyolefin material.

6. A lightweight airtight cable according to claim 5, characterized in that: The antioxidant in S33 is one or more combinations of 1010, 168, and 1076.

7. A method for processing a lightweight airtight cable according to any one of claims 1 to 6, characterized in that: The steps include: S1. Circular copper rods are drawn using a wire drawing machine. After annealing and tinning, qualified copper monofilaments are obtained through testing. The copper monofilaments are arranged and then twisted and compressed using a twisting machine using a compression die to produce a conductor. S2, wrapping the mica tape around the conductor at a wrapping angle of 45 to 65 degrees to form a fire-resistant layer, and evenly coating the conductor with molten cross-linked modified insulating polyolefin through an extruder, and air-cooling and shaping to form a conductive core; S3, twisting multiple single conductive cores into a cable, and filling with fillers in a spiral winding manner; S4. The molten low-smoke, halogen-free, flame-retardant polyolefin sheath is evenly coated on the periphery of the filler through an extruder, and air-cooled and shaped to obtain an inner sheath layer. Tinned copper wire is used to weave an armor layer. The molten low-smoke, halogen-free, flame-retardant, and oil-resistant cross-linked polyolefin material is evenly coated on the periphery of the armor layer through an extruder, and air-cooled and shaped to obtain an outer sheath layer. After the cable performance is tested and found to be qualified, it is packaged and shipped out to obtain a lightweight airtight cable.

8. A method for processing a lightweight airtight cable according to claim 7, characterized in that: The conductor in S1 is made of Z-shaped copper monofilament wrapped around cylindrical copper monofilament and pressed tightly; the mica tape wrapping overlap rate in S2 is between 30% and 40%; the braiding density of the armor layer in S4 is greater than 90%.

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