Composite cable and manufacturing method thereof

Abstract

The invention relates to the technical field of cables, and particularly discloses a composite cable and a manufacturing method thereof.The composite cable comprises a conductor core, an insulating layer, a shielding layer, a flame-retardant layer, a tensile reinforcing layer and an outer sheath, the conductor core is formed by twisting multiple strands of copper alloy wires, the insulating layer is made of a modified polyolefin material in an extruded mode, and the shielding layer is made of a flame-retardant material; the shielding layer is of a double-layer structure and is provided with the noise reduction assembly in a clamping mode, the flame-retardant layer is made of intumescent flame-retardant materials, the tensile reinforcing layer is formed by weaving aramid fibers and steel wires, and the outer sheath is made of weather-resistant polyether-ether-ketone composite materials. Through a multi-layer structure, the composite cable has excellent conductivity, insulating property, anti-interference capability, flame retardant property and mechanical strength, can adapt to complex working conditions such as high temperature, moisture and strong electromagnetic interference, ensures the structural stability and the performance consistency of the cable by accurately controlling parameters of each process, and is high in production efficiency and high in finished product qualification rate; the method is suitable for large-scale production and has a wide application prospect.

Description

Technical Field

[0001] This invention relates to the field of cable technology, and in particular to a composite cable and its manufacturing method. Background Technology

[0002] Currently, there are many types of cables on the market, but most cables suffer from limited performance. For example, traditional polyvinyl chloride (PVC) cables have poor flame retardancy and are prone to producing toxic and harmful gases in fire scenarios. They also lack mechanical strength and are difficult to adapt to complex laying environments. While some flame-retardant cables have a certain flame-retardant effect, their conductivity and anti-interference capabilities are poor, affecting the stability of signal transmission. In addition, in some special working conditions such as high temperature, humidity, and strong electromagnetic interference environments, existing cables have a short service life and are prone to problems such as insulation aging and shielding failure, which seriously affect the normal operation of equipment.

[0003] Meanwhile, existing cable manufacturing methods have shortcomings in process control, resulting in poor structural stability and performance consistency of the cables. For example, improper control of the pitch during conductor stranding can affect the conductivity and mechanical strength of the conductor; unreasonable adjustment of parameters such as temperature and pressure during insulation extrusion can easily lead to defects such as bubbles and cracks in the insulation layer; and loose bonding between the shielding layer and the insulation layer can reduce the cable's anti-interference ability. These problems not only affect the performance of the cable but also increase the scrap rate and production costs during the production process. Summary of the Invention

[0004] The main objective of this invention is to provide a composite cable and its manufacturing method, which can effectively solve the problems in the background art.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A composite cable includes, from the inside out, a conductor core, an insulation layer, a shielding layer, a flame-retardant layer, a tensile reinforcement layer, and an outer sheath;

[0007] The conductor core is formed by multiple strands of copper alloy wires twisted in the same direction, with each strand having a diameter of 0.1-0.3 mm and a twisting pitch of 10-15 times the outer diameter of the conductor core.

[0008] The insulation layer has a thickness of 0.8-1.5 mm and is made of modified polyolefin material. The modified polyolefin material is made by mixing polyolefin substrate, nano silica, antioxidant and compatibilizer in a mass ratio of 100:5-10:0.5-1:2-5.

[0009] The shielding layer includes an inner semi-conductive shielding layer, a noise reduction component, and an outer metal shielding layer. Multiple noise reduction components are uniformly arranged circumferentially between the inner semi-conductive shielding layer and the outer metal shielding layer. The noise reduction component is an elastic conductive rubber column with its axis parallel to the conductor core axis.

[0010] The thickness of the flame retardant layer is 1.2-2.0 mm, and it is made of intumescent flame retardant material. The intumescent flame retardant material is made by mixing ammonium polyphosphate, pentaerythritol, melamine and epoxy resin in a mass ratio of 40-50:20-30:15-25:10-15.

[0011] The tensile reinforcing layer is a braided layer of aramid fiber and steel wire with a braiding density of 85%-95%.

[0012] The outer sheath has a thickness of 1.5-2.5 mm and is made of weather-resistant polyether ether ketone composite material. The weather-resistant polyether ether ketone composite material is made by mixing polyether ether ketone resin, glass fiber, ultraviolet absorber and anti-aging agent in a mass ratio of 100:10-20:0.8-1.5:0.5-1.

[0013] Preferably, the copper alloy wire is made by mixing and melting copper, silver and tin in a mass ratio of 98:1.2:0.8, and then used after drawing and annealing. The annealing temperature is 400-450℃ and the holding time is 1-2h.

[0014] Preferably, the inner semi-conductive shielding layer is made of semi-conductive polyolefin material with a thickness of 0.3-0.5 mm; the outer metal shielding layer is a copper strip wrapping layer or a copper wire braiding layer, with a copper strip wrapping overlap rate of 20%-30% and a copper wire braiding density of 90%-95%.

[0015] Preferably, the noise reduction component has a diameter of 0.5-0.8 mm, a length consistent with the axial length of the shielding layer, and a spacing of 5-8 mm between adjacent noise reduction components. The elastic conductive rubber column is made by mixing and vulcanizing nitrile rubber, conductive carbon black, and vulcanizing agent in a mass ratio of 100:20-30:1-2.

[0016] Preferably, the mass ratio of aramid fiber to steel wire in the tensile reinforcing layer is 3:1, the tensile strength of the aramid fiber is ≥2800MPa, and the diameter of the steel wire is 0.2-0.4mm.

[0017] Preferably, in the weather-resistant polyetheretherketone composite material of the outer sheath, the glass fiber length is 1-3 mm, the ultraviolet absorber is UV-531 or UV-327, and the anti-aging agent is antioxidant 1010 or antioxidant 4010NA.

[0018] A method for manufacturing a composite cable includes the following steps:

[0019] (1) Preparation of conductor core: copper, silver and tin are mixed in proportion and melted at 1100-1200℃ for 2-3 hours. After casting into ingots, they are hot rolled and drawn into copper alloy wires. Multiple strands of copper alloy wires are stranded in the same direction on a stranding machine. The stranding pitch is controlled to make conductor core.

[0020] (2) Insulation layer extrusion: Polyolefin substrate, nano silica, antioxidant and compatibilizer are mixed in proportion, melted and mixed by twin screw extruder, and then extruded onto the outside of conductor core through extrusion die. The extrusion temperature is 160-180℃, the cooling water temperature is 20-30℃, and the cooling time is 3-5min to make insulated wire core.

[0021] (3) Shielding layer preparation: First, a semi-conductive polyolefin material is extruded on the outside of the insulated wire core to form an inner semi-conductive shielding layer; then, noise reduction components are evenly distributed around the outside of the inner semi-conductive shielding layer and fixed with adhesive; finally, copper strips are wrapped around the outside of the noise reduction components by a wrapping machine or copper wires are braided by a braiding machine to form an outer metal shielding layer, thus making a shielded wire core.

[0022] (4) Flame retardant layer extrusion: Ammonium polyphosphate, pentaerythritol, melamine and epoxy resin are mixed evenly in proportion, melted by an extruder and extruded onto the outside of the shielded wire core. The extrusion temperature is 150-170℃. After cooling to room temperature, the flame retardant wire core is made.

[0023] (5) Tensile reinforcement layer weaving: Aramid fiber and steel wire are mixed in proportion and woven on the outside of the flame-retardant wire core by a braiding machine to form a tensile reinforcement layer, and the weaving density is controlled;

[0024] (6) Outer sheath extrusion: Polyether ether ketone resin, glass fiber, ultraviolet absorber and anti-aging agent are mixed in proportion, melt-mixed by twin screw extruder, and then extruded on the outside of the tensile reinforcement layer. The extrusion temperature is 300-320℃, the cooling water temperature is 30-40℃, and the cooling time is 5-8min.

[0025] (7) Finished product processing: After the cable with the extruded outer sheath is pulled and wound up, it is made into a composite cable after passing the appearance inspection, size measurement and performance test.

[0026] Preferably, in step (1), the wire drawing process adopts multiple wire drawing, the reduction rate of each wire drawing is 15%-20%, and the diameter deviation of the copper alloy wire after wire drawing is ≤±0.01mm; the annealing treatment is carried out under a nitrogen protective atmosphere, and the nitrogen purity is ≥99.9%.

[0027] Preferably, in step (3), the adhesive is epoxy resin adhesive with a coating thickness of 0.1-0.2 mm, and is cured at 80-100℃ for 1-2 hours after coating; the tension of the copper strip wrapping is 50-80 N, and the tension of the copper wire braiding is 30-50 N.

[0028] Compared with the prior art, the present invention provides a highly efficient water-based nano-silicone rubber sealing and waterproofing agent, which has the following beneficial effects:

[0029] 1. This invention adopts a multi-layer structure. The conductor core is made of copper-silver-tin alloy wire stranded together, which has excellent conductivity and high mechanical strength. The insulation layer is made of modified polyolefin material, which has good insulation performance, strong heat resistance and anti-aging ability. The shielding layer adopts a double-layer structure and is equipped with noise reduction components, which has a significant anti-interference effect and can also absorb vibration and noise. The flame retardant layer is made of intumescent flame retardant material, which has excellent flame retardant performance and is environmentally friendly. The tensile reinforcement layer is woven from aramid fiber and steel wire, which has outstanding tensile, bending and impact resistance. The outer sheath is made of weather-resistant polyetheretherketone composite material, which has strong weather resistance and can adapt to complex environments. The various layers work together to make the cable have excellent comprehensive performance and can be widely used in power, communication, industrial control and other fields, especially suitable for complex working conditions such as high temperature, humidity and strong electromagnetic interference.

[0030] 2. The manufacturing method of this invention has a standardized process and precise control of parameters in each process. During the preparation of the conductor core, the melting temperature, wire drawing reduction rate and annealing parameters are strictly controlled to ensure the conductivity and mechanical strength of the conductor core. During the extrusion process of the insulation layer and outer sheath, the temperature, pressure and cooling parameters are optimized to avoid defects. During the preparation of the shielding layer, attention is paid to the fixing of the noise reduction components and the weaving of the metal shielding layer to improve the anti-interference effect, ensure the stability of the cable structure and the consistency of performance, and achieve high production efficiency and high finished product qualification rate, making it suitable for large-scale production.

[0031] 3. All layers of the composite cable of the present invention are made of environmentally friendly materials. No toxic or harmful gases are produced when the flame-retardant layer burns. The outer sheath has strong aging resistance and a long service life, which is in line with the development trend of green environmental protection and has good economic and social benefits. Detailed Implementation

[0032] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0033] Example 1

[0034] A composite cable includes, from the inside out, a conductor core, an insulation layer, a shielding layer, a flame-retardant layer, a tensile reinforcement layer, and an outer sheath;

[0035] The conductor core is made of multiple strands of copper alloy wire twisted in the same direction. Each strand of copper alloy wire has a diameter of 0.2 mm, and the twist pitch is 12 times the outer diameter of the conductor core. The copper alloy wire is made by mixing and melting copper, silver, and tin in a mass ratio of 98:1.2:0.8. It is used after wire drawing and annealing. The annealing temperature is 420℃ and the holding time is 1.5 h.

[0036] The insulation layer is 1.2 mm thick and is made of modified polyolefin material. The modified polyolefin material is made by mixing polyolefin substrate, nano silica, antioxidant 1010 and compatibilizer maleic anhydride grafted polyethylene in a mass ratio of 100:8:0.8:3.

[0037] The shielding layer includes an inner semi-conductive shielding layer, noise reduction components, and an outer metal shielding layer. The inner semi-conductive shielding layer is made of semi-conductive polyolefin material with a thickness of 0.4 mm. The outer metal shielding layer is a copper strip wrapping layer with a wrapping overlap rate of 25%. Multiple noise reduction components are uniformly arranged circumferentially between the inner semi-conductive shielding layer and the outer metal shielding layer. The noise reduction components are elastic conductive rubber pillars with a diameter of 0.6 mm and a spacing of 6 mm between adjacent noise reduction components. The elastic conductive rubber pillars are made by vulcanizing a mixture of nitrile rubber, conductive carbon black, and vulcanizing agent dicumyl peroxide in a mass ratio of 100:25:1.5.

[0038] The flame retardant layer is 1.6 mm thick and is made of intumescent flame retardant material, which is a mixture of ammonium polyphosphate, pentaerythritol, melamine and epoxy resin in a mass ratio of 45:25:20:10.

[0039] The tensile reinforcement layer is a braided layer of aramid fiber and steel wire with a braiding density of 90%, a mass ratio of aramid fiber to steel wire of 3:1, a tensile strength of aramid fiber of 2900MPa, and a diameter of steel wire of 0.3mm.

[0040] The outer sheath is 2.0 mm thick and is made of weather-resistant polyetheretherketone composite material. It is made of polyetheretherketone resin, glass fiber, ultraviolet absorber UV-531 and anti-aging agent 1010 mixed in a mass ratio of 100:15:1.2:0.8.

[0041] The manufacturing method of the above-mentioned composite cable includes the following steps:

[0042] (1) Conductor core preparation: Copper, silver, and tin are mixed in proportion and put into a medium-frequency induction furnace, and melted at 1150℃ for 2.5h. Argon gas is introduced for protection during the melting process. After casting into ingots, they are hot-rolled into round bars, and then drawn into copper alloy wires through multiple passes. The reduction rate of each drawing pass is 18%, and the diameter deviation of the copper alloy wire is ≤±0.01mm. The drawn copper alloy wires are annealed in an annealing furnace at a temperature of 420℃ and a holding time of 1.5h. The annealing is carried out under a nitrogen protective atmosphere with a nitrogen purity ≥99.9%. The multiple strands of annealed copper alloy wires are stranded in the same direction on a stranding machine, and the stranding pitch is controlled to be 12 times the outer diameter of the conductor core to make the conductor core.

[0043] (2) Insulation layer extrusion: Polyolefin substrate, nano silica, antioxidant 1010 and compatibilizer maleic anhydride grafted polyethylene are put into a high-speed mixer in proportion and mixed at 90°C for 12 minutes. After being mixed evenly, it is sent to a twin-screw extruder for melt mixing. The screw speed of the twin-screw extruder is 350 r / min and the barrel temperature is 160°C. The melt-mixed material is extruded through the extrusion die onto the outside of the conductor core. The extrusion temperature is 170°C and the extrusion pressure is 18 MPa. The extruded insulated wire core is immediately cooled in a cooling water tank at 25°C for 4 minutes. After cooling, it is pulled to the next process by a traction machine.

[0044] (3) Shielding layer preparation: First, a semi-conductive polyolefin material is extruded onto the outside of the insulated core using an extruder to form an inner semi-conductive shielding layer. The extrusion temperature is 155℃ and the thickness is controlled at 0.4mm. Then, noise reduction components are evenly distributed circumferentially on the outside of the inner semi-conductive shielding layer. Epoxy resin is applied to both ends of the noise reduction components with a coating thickness of 0.15mm. The noise reduction components are fixed to the surface of the inner semi-conductive shielding layer and then cured at 90℃ for 1.5h. Finally, copper strip is wrapped around the outside of the noise reduction components using a wrapping machine to form an outer metal shielding layer. The tension of the copper strip wrapping is 65N and the overlap rate is 25%, thus producing the shielded core.

[0045] (4) Flame retardant layer extrusion: Ammonium polyphosphate, pentaerythritol, melamine and epoxy resin are added to a mixer in proportion and mixed for 25 minutes until uniform. Then the mixture is fed into an extruder to melt. The barrel temperature of the extruder is 150℃ and the screw speed is 250r / min. The molten flame retardant material is extruded onto the outside of the shielded wire core. The extrusion temperature is 160℃ and the extrusion pressure is 15MPa. The flame retardant wire core is naturally cooled to room temperature after extrusion to make a flame retardant wire core.

[0046] (5) Tensile reinforcement layer weaving: Aramid fiber and steel wire are mixed at a mass ratio of 3:1, drawn out through the wire feeding frame and fed into the braiding machine to form a tensile reinforcement layer on the outside of the flame retardant wire core. The speed of the braiding machine is 120r / min and the braiding density is controlled at 90%.

[0047] (6) Outer sheath extrusion: Polyether ether ketone resin, glass fiber, UV absorber UV-531 and anti-aging agent 1010 are added to a high-speed mixer in proportion and mixed at 130°C for 18 minutes. After being mixed evenly, the mixture is fed into a twin-screw extruder for melt mixing. The screw speed of the twin-screw extruder is 300 r / min and the barrel temperature is 290°C. The melt-mixed material is extruded through an extrusion die onto the outside of the tensile reinforcement layer. The extrusion temperature is 310°C and the extrusion pressure is 22 MPa. The extruded cable is cooled in a cooling water tank at 35°C for 6 minutes to allow the outer sheath to solidify.

[0048] (7) Finished product processing: The cooled cable is pulled to the take-up machine by the traction machine at a take-up speed of 8m / min. The cable after take-up is subjected to appearance inspection, size measurement and performance testing. All indicators meet the design requirements. The cable is cut and packaged according to the specified length to make composite cable finished product.

[0049] Example 2

[0050] A composite cable includes, from the inside out, a conductor core, an insulation layer, a shielding layer, a flame-retardant layer, a tensile reinforcement layer, and an outer sheath.

[0051] The conductor core is made of multiple strands of copper alloy wire twisted in the same direction. The diameter of each copper alloy wire is 0.1 mm, and the twisting pitch is 10 times the outer diameter of the conductor core. The copper alloy wire is made by mixing and melting copper, silver and tin in a mass ratio of 98:1.2:0.8. It is used after wire drawing and annealing. The annealing temperature is 400℃ and the holding time is 1 hour.

[0052] The insulation layer is 0.8 mm thick and is made of modified polyolefin material. The modified polyolefin material is made by mixing polyolefin substrate, nano silica, antioxidant 1076 and compatibilizer maleic anhydride grafted polypropylene in a mass ratio of 100:5:0.5:2.

[0053] The shielding layer includes an inner semi-conductive shielding layer, noise reduction components, and an outer metal shielding layer. The inner semi-conductive shielding layer is made of semi-conductive polyolefin material with a thickness of 0.3 mm. The outer metal shielding layer is a copper wire braided layer with a braiding density of 90%. Multiple noise reduction components are uniformly arranged circumferentially between the inner semi-conductive shielding layer and the outer metal shielding layer. The noise reduction components are elastic conductive rubber pillars with a diameter of 0.5 mm and a spacing of 5 mm between adjacent noise reduction components. The elastic conductive rubber pillars are made by vulcanizing a mixture of nitrile rubber, conductive carbon black, and vulcanizing agent benzoyl peroxide in a mass ratio of 100:20:1.

[0054] The flame retardant layer is 1.2 mm thick and is made of intumescent flame retardant material, which is a mixture of ammonium polyphosphate, pentaerythritol, melamine and epoxy resin in a mass ratio of 40:20:15:10.

[0055] The tensile reinforcement layer is a braided layer of aramid fiber and steel wire with a braiding density of 85%, a mass ratio of aramid fiber to steel wire of 3:1, a tensile strength of aramid fiber of 2800MPa, and a diameter of steel wire of 0.2mm.

[0056] The outer sheath is 1.5mm thick and is made of weather-resistant polyetheretherketone composite material. It is made of polyetheretherketone resin, glass fiber, ultraviolet absorber UV-327 and anti-aging agent 4010NA mixed in a mass ratio of 100:10:0.8:0.5.

[0057] The manufacturing method of the above-mentioned composite cable includes the following steps:

[0058] (1) Conductor core preparation: Copper, silver and tin are mixed in proportion and put into a medium frequency induction furnace. They are melted at 1100℃ for 2 hours. Argon gas is introduced for protection during the melting process. After casting into an ingot, it is hot rolled into a round bar and then drawn into copper alloy wire through multiple passes. The reduction rate of each drawing pass is 15%. The diameter deviation of the copper alloy wire is ≤ ±0.01mm. The drawn copper alloy wire is annealed in an annealing furnace at a temperature of 400℃ and a holding time of 1 hour. The annealing is carried out under a nitrogen protective atmosphere with a nitrogen purity ≥ 99.9%. The multiple strands of annealed copper alloy wire are stranded in the same direction on a stranding machine. The stranding pitch is controlled to be 10 times the outer diameter of the conductor core to make the conductor core.

[0059] (2) Insulation layer extrusion: Polyolefin substrate, nano silica, antioxidant 1076 and compatibilizer maleic anhydride grafted polypropylene are put into a high-speed mixer in proportion and mixed at 80°C for 10 min. After being mixed evenly, it is sent to a twin-screw extruder for melt mixing. The screw speed of the twin-screw extruder is 300 r / min and the barrel temperature is 150°C. The melt-mixed material is extruded onto the outside of the conductor core through the extrusion die. The extrusion temperature is 160°C and the extrusion pressure is 15 MPa. The extruded insulated wire core is immediately cooled in a cooling water tank. The cooling water temperature is 20°C and the cooling time is 3 min. After cooling, it is pulled to the next process by a traction machine.

[0060] (3) Shielding layer preparation: First, a semi-conductive polyolefin material is extruded on the outside of the insulated wire core to form an inner semi-conductive shielding layer. The extrusion temperature is 150℃ and the thickness is controlled at 0.3mm. Then, noise reduction components are evenly arranged on the outside of the inner semi-conductive shielding layer. Epoxy resin is applied to both ends of the noise reduction components with a coating thickness of 0.1mm. The noise reduction components are fixed on the surface of the inner semi-conductive shielding layer and then cured at 80℃ for 1h. Finally, copper wire is braided on the outside of the noise reduction components to form an outer metal shielding layer. The tension of the copper wire braid is 30N and the braiding density is 90%, thus making a shielded wire core.

[0061] (4) Flame retardant layer extrusion: Ammonium polyphosphate, pentaerythritol, melamine and epoxy resin are added to a mixer in proportion and mixed for 20 minutes until uniform. Then the mixture is fed into an extruder to melt. The barrel temperature of the extruder is 140℃ and the screw speed is 200r / min. The molten flame retardant material is extruded onto the outside of the shielded wire core. The extrusion temperature is 150℃ and the extrusion pressure is 12MPa. The flame retardant wire core is naturally cooled to room temperature after extrusion to make a flame retardant wire core.

[0062] (5) Tensile reinforcement layer weaving: Aramid fiber and steel wire are mixed at a mass ratio of 3:1, drawn out through the wire feeding frame and fed into the braiding machine to form a tensile reinforcement layer on the outside of the flame retardant wire core. The speed of the braiding machine is 100r / min and the braiding density is controlled at 85%.

[0063] (6) Outer sheath extrusion: Polyether ether ketone resin, glass fiber, UV absorber UV-327 and anti-aging agent 4010NA are added to a high-speed mixer in proportion and mixed at 120°C for 15 minutes. After uniform mixing, the mixture is fed into a twin-screw extruder for melt mixing. The screw speed of the twin-screw extruder is 250 r / min and the barrel temperature is 280°C. The melt-mixed material is extruded through an extrusion die onto the outside of the tensile reinforcement layer. The extrusion temperature is 300°C and the extrusion pressure is 20 MPa. The extruded cable is cooled in a cooling water tank at 30°C for 5 minutes to allow the outer sheath to solidify.

[0064] (7) Finished product processing: The cooled cable is pulled to the take-up machine by the traction machine at a take-up speed of 5m / min. The cable after take-up is inspected for appearance, measured for size and tested for performance. All indicators meet the design requirements. The cable is cut and packaged to the specified length to make composite cable finished product.

[0065] Example 3

[0066] A composite cable includes, from the inside out, a conductor core, an insulation layer, a shielding layer, a flame-retardant layer, a tensile reinforcement layer, and an outer sheath.

[0067] The conductor core is made of multiple strands of copper alloy wires twisted in the same direction. The diameter of each copper alloy wire is 0.3mm, and the twisting pitch is 15 times the outer diameter of the conductor core. The copper alloy wire is made by mixing and melting copper, silver and tin in a mass ratio of 98:1.2:0.8. It is used after wire drawing and annealing. The annealing temperature is 450℃ and the holding time is 2h.

[0068] The insulation layer is 1.5 mm thick and is made of modified polyolefin material. The modified polyolefin material is made by mixing polyolefin substrate, nano silica, antioxidant 1010 and compatibilizer maleic anhydride grafted polyethylene in a mass ratio of 100:10:1:5.

[0069] The shielding layer includes an inner semi-conductive shielding layer, noise reduction components, and an outer metal shielding layer. The inner semi-conductive shielding layer is made of semi-conductive polyolefin material with a thickness of 0.5 mm. The outer metal shielding layer is a copper strip wrapping layer with a wrapping overlap rate of 30%. Multiple noise reduction components are uniformly arranged circumferentially between the inner semi-conductive shielding layer and the outer metal shielding layer. The noise reduction components are elastic conductive rubber pillars with a diameter of 0.8 mm and a spacing of 8 mm between adjacent noise reduction components. The elastic conductive rubber pillars are made by vulcanizing a mixture of nitrile rubber, conductive carbon black, and vulcanizing agent dicumyl peroxide in a mass ratio of 100:30:2.

[0070] The flame retardant layer is 2.0 mm thick and is made of intumescent flame retardant material, which is a mixture of ammonium polyphosphate, pentaerythritol, melamine and epoxy resin in a mass ratio of 50:30:25:15.

[0071] The tensile reinforcement layer is a braided layer of aramid fiber and steel wire with a braiding density of 95%, a mass ratio of aramid fiber to steel wire of 3:1, a tensile strength of aramid fiber of 3000MPa, and a diameter of steel wire of 0.4mm.

[0072] The outer sheath is 2.5mm thick and is made of weather-resistant polyetheretherketone composite material, which is made of polyetheretherketone resin, glass fiber, ultraviolet absorber UV-531 and anti-aging agent 1010 mixed in a mass ratio of 100:20:1.5:1.

[0073] The manufacturing method of the above-mentioned composite cable includes the following steps:

[0074] (1) Conductor core preparation: Copper, silver and tin are mixed in proportion and put into a medium frequency induction furnace. They are melted at 1200℃ for 3 hours. Argon gas is introduced for protection during the melting process. After casting into ingots, they are hot rolled into round bars and then drawn into copper alloy wires through multiple passes. The reduction rate of each drawing pass is 20%, and the diameter deviation of the copper alloy wire is ≤±0.01mm. The drawn copper alloy wires are annealed in an annealing furnace at a temperature of 450℃ for 2 hours. The annealing is carried out under a nitrogen protective atmosphere with a nitrogen purity ≥99.9%. The multiple strands of annealed copper alloy wires are stranded in the same direction on a stranding machine. The stranding pitch is controlled to be 15 times the outer diameter of the conductor core to make the conductor core.

[0075] (2) Insulation layer extrusion: Polyolefin substrate, nano silica, antioxidant 1010 and compatibilizer maleic anhydride grafted polyethylene are put into a high-speed mixer in proportion and mixed at 100°C for 15 minutes. After being mixed evenly, it is sent to a twin-screw extruder for melt mixing. The screw speed of the twin-screw extruder is 400 r / min and the barrel temperature is 170°C. The melt-mixed material is extruded onto the outside of the conductor core through the extrusion die. The extrusion temperature is 180°C and the extrusion pressure is 20 MPa. The extruded insulated wire core is immediately cooled in a cooling water tank. The cooling water temperature is 30°C and the cooling time is 5 minutes. After cooling, it is pulled to the next process by a traction machine.

[0076] (3) Shielding layer preparation: First, a semi-conductive polyolefin material is extruded on the outside of the insulated wire core to form an inner semi-conductive shielding layer. The extrusion temperature is 160℃ and the thickness is controlled at 0.5mm. Then, noise reduction components are evenly distributed circumferentially on the outside of the inner semi-conductive shielding layer. Epoxy resin is applied to both ends of the noise reduction components with a coating thickness of 0.2mm. The noise reduction components are fixed on the surface of the inner semi-conductive shielding layer and then cured at 100℃ for 2 hours. Finally, copper strip is wrapped on the outside of the noise reduction components to form an outer metal shielding layer. The tension of the copper strip wrapping is 80N and the overlap rate is 30%, thus making a shielded wire core.

[0077] (4) Flame retardant layer extrusion: Ammonium polyphosphate, pentaerythritol, melamine and epoxy resin are added to a mixer in proportion and mixed for 30 minutes until uniform. Then the mixture is fed into an extruder to melt. The barrel temperature of the extruder is 160℃ and the screw speed is 300r / min. The molten flame retardant material is extruded onto the outside of the shielded wire core. The extrusion temperature is 170℃ and the extrusion pressure is 18MPa. The flame retardant wire core is naturally cooled to room temperature after extrusion to make a flame retardant wire core.

[0078] (5) Tensile reinforcement layer weaving: Aramid fiber and steel wire are mixed at a mass ratio of 3:1, drawn out through the wire feeding frame and fed into the braiding machine to form a tensile reinforcement layer on the outside of the flame retardant wire core. The speed of the braiding machine is 150 r / min and the braiding density is controlled at 95%.

[0079] (6) Outer sheath extrusion: Polyether ether ketone resin, glass fiber, UV absorber UV-531 and anti-aging agent 1010 are added to a high-speed mixer in proportion and mixed at 140°C for 20 minutes. After being mixed evenly, the mixture is fed into a twin-screw extruder for melt mixing. The screw speed of the twin-screw extruder is 350 r / min and the barrel temperature is 300°C. The melt-mixed material is extruded through an extrusion die onto the outside of the tensile reinforcement layer. The extrusion temperature is 320°C and the extrusion pressure is 25 MPa. The extruded cable is cooled in a cooling water tank at 40°C for 8 minutes to allow the outer sheath to solidify.

[0080] (7) Finished product processing: The cooled cable is pulled to the take-up machine by the traction machine at a take-up speed of 10m / min. The cable after take-up is subjected to appearance inspection, size measurement and performance testing. All indicators meet the design requirements. The cable is then cut and packaged to the specified length to make the composite cable finished product.

[0081] The composite cables prepared in Examples 1-3 above were subjected to performance tests, and the test results are shown in the table below:

[0082] Test Project Example 1 Example 2 Example 3 Standard requirements DC resistance of conductor core (Ω / km) 0.015 0.016 0.014 ≤0.017 Insulation breakdown electric field strength (kV / mm) 28 26 30 ≥25 Flame retardant rating: Class A Grade A Grade A Grade A GB / T18380-2008 Tensile strength at break (MPa) 165 155 170 ≥150 Tensile strength retention rate after 720h accelerated aging (%) 88 85 90 ≥85 Elongation at break retention rate (%) after 720h artificial accelerated aging 83 80 85 ≥80

[0083] The test results show that the composite cable prepared by this invention meets all the design requirements. It exhibits excellent conductivity, insulation, flame retardancy, tensile strength and weather resistance, and has good application prospects.

[0084] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A composite cable, characterized by The conductor core, the insulating layer, the shielding layer, the flame-retardant layer, the tensile-strengthening layer and the outer sheath are sequentially arranged from inside to outside. The conductor core is made of a plurality of copper alloy wires which are twisted in the same direction, the diameter of each copper alloy wire is 0.1-0.3mm, and the twisting pitch is 10-15 times of the outer diameter of the conductor core. The thickness of the insulating layer is 0.8-1.5mm, and the insulating layer is made of modified polyolefin material, the modified polyolefin material is made by mixing polyolefin base material, nano-silicon dioxide, antioxidant and compatible agent according to the mass ratio of 100:5-10:0.5-1:2-5. The shielding layer comprises an inner semi-conductive shielding layer, a noise reduction component and an outer metal shielding layer, a plurality of noise reduction components are evenly arranged between the inner semi-conductive shielding layer and the outer metal shielding layer in the circumferential direction, the noise reduction component is an elastic conductive rubber column, and the axis of the noise reduction component is parallel to the axis of the conductor core. The thickness of the flame-retardant layer is 1.2-2.0mm, and the flame-retardant layer is made of intumescent flame-retardant material, the intumescent flame-retardant material is made by mixing ammonium polyphosphate, pentaerythritol, melamine and epoxy resin according to the mass ratio of 40-50:20-30:15-25:10-15. The tensile-strengthening layer is a woven layer of aramid fiber and steel wire, and the weaving density is 85%-95%. The thickness of the outer sheath is 1.5-2.5mm, and the outer sheath is made of weather-resistant polyether ether ketone composite material, the weather-resistant polyether ether ketone composite material is made by mixing polyether ether ketone resin, glass fiber, ultraviolet absorber and anti-aging agent according to the mass ratio of 100:10-20:0.8-1.5:0.5-1.

2. A composite cable according to claim 1, characterized in that The copper alloy wire is made by mixing copper, silver and tin according to the mass ratio of 98:1.2:0.8, and then melting, drawing and annealing, the annealing temperature is 400-450℃, and the holding time is 1-2h.

3. A composite cable according to claim 1, wherein The inner semi-conductive shielding layer is made of semi-conductive polyolefin material, and the thickness is 0.3-0.5mm; the outer metal shielding layer is a copper tape wrapping layer or a copper wire weaving layer, the copper tape wrapping overlap rate is 20%-30%, and the copper wire weaving density is 90%-95%.

4. The composite cable of claim 1, wherein, The diameter of the noise reduction component is 0.5-0.8mm, the length of the noise reduction component is consistent with the axial length of the shielding layer, and the spacing between adjacent noise reduction components is 5-8mm, the elastic conductive rubber column is made by mixing nitrile rubber, conductive carbon black and vulcanizing agent according to the mass ratio of 100:20-30:1-2.

5. The composite cable of claim 1, wherein, The mass ratio of aramid fiber to steel wire in the tensile-strengthening layer is 3:1, the breaking strength of the aramid fiber is greater than or equal to 2800MPa, and the diameter of the steel wire is 0.2-0.4mm.

6. A composite cable according to claim 5, wherein, In the weather-resistant polyether ether ketone composite material of the outer sheath, the length of the glass fiber is 1-3mm, the ultraviolet absorber is UV-531 or UV-327, and the anti-aging agent is antioxidant 1010 or antioxidant 4010NA.

7. A method of manufacturing a composite cable as claimed in any one of claims 1 to 6, characterized in that, The method comprises the following steps: (1) Conductor core preparation: mix copper, silver and tin according to the proportion, melt at 1100-1200℃ for 2-3h, cast into ingots, and then hot-rolled and drawn into copper alloy wires, twist a plurality of copper alloy wires in the same direction on a twisting machine to control the twisting pitch, and then make the conductor core. (2) Insulating layer extrusion: polyolefin base material, nano-silicon dioxide, antioxidant and compatibility agent are mixed in proportion, melt mixed by double screw extruder, and then extruded on the outside of the conductor core through the extrusion die. The extrusion temperature is 160-180℃, the cooling water temperature is 20-30℃, and the cooling time is 3-5min. The insulating wire core is prepared. (3) Shielding layer preparation: first, extrude the semi-conductive polyolefin material on the outside of the insulating wire core to form the inner semi-conductive shielding layer; then arrange the noise reduction assembly on the outer side of the inner semi-conductive shielding layer in a circumferential direction, and fix it with an adhesive; finally, wrap the copper strip on the outside of the noise reduction assembly by a wrapping machine or weave the copper wire by a braiding machine to form the outer metal shielding layer, and prepare the shielding wire core. (4) Flame-retardant layer extrusion: ammonium polyphosphate, pentaerythritol, melamine and epoxy resin are mixed uniformly in proportion, melted by an extruder, and then extruded on the outside of the shielding wire core. The extrusion temperature is 150-170℃, and the cooling temperature is room temperature. The flame-retardant wire core is prepared. (5) Tensile strength reinforcing layer braiding: aramid fiber and steel wire are mixed in proportion, and braided on the outside of the flame-retardant wire core by a braiding machine to form the tensile strength reinforcing layer. The braiding density is controlled. (6) Outer sheath extrusion: polyether ether ketone resin, glass fiber, ultraviolet absorber and anti-aging agent are mixed in proportion, melt mixed by a double screw extruder, and then extruded on the outside of the tensile strength reinforcing layer. The extrusion temperature is 300-320℃, the cooling water temperature is 30-40℃, and the cooling time is 5-8min. (7) Product processing: the cable after extruding the outer sheath is drawn and wound. After appearance detection, size measurement and performance test, the composite cable product is prepared.

8. The method of manufacturing a composite cable according to claim 7, wherein In step (1), the drawing process adopts multi-pass drawing, and the area reduction rate of each pass is 15%-20%. The diameter deviation of the copper alloy wire after drawing is ≤±0.01mm. The annealing treatment is carried out in a nitrogen atmosphere with a purity of ≥99.9%.

9. The method of manufacturing a composite cable according to claim 7, wherein In step (3), the adhesive is epoxy resin glue with a coating thickness of 0.1-0.2mm. After coating, it is cured at 80-100℃ for 1-2h. The tension of the copper strip wrapping is 50-80N, and the tension of the copper wire braiding is 30-50N.