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CN-122000138-A - Copper-shielded track traffic cable with high dynamic stability and preparation method thereof

CN122000138ACN 122000138 ACN122000138 ACN 122000138ACN-122000138-A

Abstract

The invention discloses a high dynamic stability copper shielding track traffic cable and a preparation method thereof, comprising the following steps of putting an ethylene-vinyl acetate copolymer, an inorganic flame retardant filler, layered silicate and carboxylated carbon nanotubes into a double-screw extruder for melt blending and underwater granulating to obtain a functional insulating material; the method comprises the steps of extruding a functional insulating material on a conductor to form a functional insulating layer, sequentially forming a conductor shielding layer and an insulating shielding layer outside the functional insulating layer, forming a composite copper shielding layer outside the insulating shielding layer, wrapping Bao Daiceng the composite copper shielding layer, and extruding an outer sheath layer outside a wrapping belt layer. The invention forms the controlled discontinuous maximum conductive cluster in the functional insulating layer by the surface pretreatment and the specific shearing process of the carboxylated carbon nano tube, the area ratio is less than or equal to 5 percent, the insulating resistance is ensured, the performance degradation caused by the local accumulation of charges is avoided, and the structural stability and the local discharge resistance of the insulating material under the dynamic stress are obviously improved.

Inventors

  • SHEN XIAOPING
  • LIU JUN
  • ZHOU JIANG
  • XIA LANLAN

Assignees

  • 江苏通鼎光电科技有限公司

Dates

Publication Date
20260508
Application Date
20260313

Claims (10)

  1. 1. The preparation method of the copper shielding track traffic cable with high dynamic stability is characterized by comprising the following steps of: s1, preparing a functional insulating material: feeding ethylene-vinyl acetate copolymer, inorganic flame-retardant filler, phyllosilicate and carboxylated carbon nanotubes into a double-screw extruder, carrying out melt blending and underwater granulating under a shearing mixing field formed by a melting temperature of 130-160 ℃ and a screw rotating speed of 200-400rpm to obtain a functional insulating material; S2, extruding the functional insulating material prepared in the step S1 on a conductor to form a functional insulating layer; s3, forming a conductor shielding layer and an insulation shielding layer outside the functional insulation layer in sequence; S4, forming a composite copper shielding layer outside the insulating shielding layer; S5, wrapping Bao Daiceng the composite copper shielding layer, and extruding an outer sheath layer outside the wrapping belt layer.
  2. 2. The method for preparing the high dynamic stability copper shielding rail transit cable according to claim 1, wherein in the step S1, the parts by weight of the ethylene-vinyl acetate copolymer, the inorganic flame retardant filler, the layered silicate and the carboxylated carbon nanotubes are 45-50 parts, 85-95 parts, 6-9 parts and 1-3 parts, respectively.
  3. 3. The method for preparing the high dynamic stability copper shielding rail transit cable according to claim 1 or 2, wherein the VA content of the ethylene-vinyl acetate copolymer is 25% -30%; The inorganic flame-retardant filler adopts aluminum hydroxide or magnesium hydroxide with the average particle diameter D50 less than or equal to 1 mu m; the layered silicate is organized montmorillonite.
  4. 4. The method for preparing the high dynamic stability copper shielding track traffic cable according to claim 1, wherein in the step S1, the carboxylated carbon nanotubes and a silane coupling agent accounting for 5-8% of the weight of the carboxylated carbon nanotubes are ultrasonically dispersed in an ethanol solution for 20-40min and subjected to surface pretreatment, the pretreated carbon nanotubes and a part of ethylene-vinyl acetate copolymer are premixed into master batches, and finally the master batches, the inorganic flame retardant filler, the layered silicate and the residual ethylene-vinyl acetate copolymer are put into a double screw extruder.
  5. 5. The method for preparing the copper-shielded track traffic cable with high dynamic stability according to claim 4, wherein the pretreated carbon nanotubes are premixed with ethylene-vinyl acetate copolymer accounting for 20% -25% of the total amount of the ethylene-vinyl acetate copolymer to prepare master batch, and then are fed into a twin-screw extruder together with inorganic flame retardant filler, layered silicate and ethylene-vinyl acetate copolymer accounting for 75% -80% of the total amount of the ethylene-vinyl acetate copolymer.
  6. 6. The method for preparing a high dynamic stability copper shielding track traffic cable according to claim 1, wherein in step S1, the functionalized insulating material satisfies: The microcosmic morphology of the functional insulating material is in the atomic force microscope conductive extension mode, in the observation area of 10 mu m multiplied by 10 mu m, the area occupied ratio average value of the largest continuous conductive clusters obtained through binarization treatment statistics is not more than 5%.
  7. 7. The method for preparing the high dynamic stability copper shielding track traffic cable according to claim 1, wherein in the step S4, the composite copper shielding layer comprises a copper strip and a copper wire braid sequentially arranged from inside to outside, and the step of forming the composite copper shielding layer outside the insulating shielding layer comprises: S4.1, wrapping the copper strips, namely wrapping the copper strips with the thickness of 0.05-0.08mm outside the insulating shielding layer, wherein the wrapping lap rate is 35-45%, and the lap rate fluctuation on any 1 meter length is less than or equal to +/-2%; s4.2, braiding high-density copper wires, namely braiding outside the copper strips to form a copper wire braiding layer, wherein the braiding density of the copper wire braiding layer is controlled to be 94% -96%.
  8. 8. The method for preparing the high dynamic stability copper shielding track traffic cable according to claim 7, wherein in the step S4.2, the low melting point tin-bismuth alloy paste is precoated on the surface of the copper strip, then the copper strip is braided, and then the low melting point tin-bismuth alloy paste is melted, leveled and solidified through a hot press roller.
  9. 9. The method for manufacturing a high dynamic stability copper shielded track traffic cable according to claim 7, wherein in step S4.2, after braiding is completed, local spot welding is performed along the longitudinal interval of the cable using an ultrasonic spot welding device.
  10. 10. The high-dynamic-stability copper-shielded track traffic cable is characterized by being prepared by adopting the preparation method of the high-dynamic-stability copper-shielded track traffic cable according to any one of claims 1-9, and comprises a conductor, a functional insulating layer, a conductor shielding layer, an insulating shielding layer, a composite copper shielding layer, a wrapping band layer and an outer sheath layer which are sequentially arranged from inside to outside, wherein the composite copper shielding layer comprises a copper strip and a copper wire weaving layer which are sequentially arranged from inside to outside.

Description

Copper-shielded track traffic cable with high dynamic stability and preparation method thereof Technical Field The invention belongs to the technical field of cables, and particularly relates to a high dynamic stability copper shielding track traffic cable and a preparation method thereof. Background The on-board electrical system of rail transit vehicles (e.g., high-speed trains, subways) is the neural hub of their safe operation. In a typical 'electro-magnetic-force' multi-physical field with strong electromagnetic interference, continuous mechanical vibration and repeated bending stress coupling effect, the system has strict requirements on cables for transmitting signals, namely extremely high initial shielding efficiency is required to resist the electromagnetic interference, and the shielding performance is not obviously deteriorated after the cables bear tens of millions of vibration cycles in a service period of decades. In the industry, a simple copper strip wrapping or copper wire braiding structure is commonly adopted, and the problems of loose lap joint surface, braided wire displacement and the like are easy to occur under the action of dynamic stress, so that the shielding effectiveness is reduced. At present, some improved shielding structures such as composite shielding, bonding shielding layers and the like exist, but long-term shielding stability under high-frequency vibration is still not ideal, the process control difficulty is high, and the severe requirement that shielding effectiveness attenuation is not more than 3dB after 10-7 times of axial vibration test in IEC 61373:2010 standard is difficult to meet. Disclosure of Invention The invention aims to solve the problems in the prior art and provide a copper-shielded track traffic cable with high dynamic stability and a preparation method thereof. In order to achieve the above purpose and achieve the above technical effects, the invention adopts the following technical scheme: the preparation method of the copper shielding track traffic cable with high dynamic stability comprises the following steps: s1, preparing a functional insulating material: feeding ethylene-vinyl acetate copolymer, inorganic flame-retardant filler, phyllosilicate and carboxylated carbon nanotubes into a double-screw extruder, carrying out melt blending and underwater granulating under a shearing mixing field formed by a melting temperature of 130-160 ℃ and a screw rotating speed of 200-400rpm to obtain a functional insulating material; S2, extruding the functional insulating material prepared in the step S1 on a conductor to form a functional insulating layer; s3, forming a conductor shielding layer and an insulation shielding layer outside the functional insulation layer in sequence; S4, forming a composite copper shielding layer outside the insulating shielding layer; S5, wrapping Bao Daiceng the composite copper shielding layer, and extruding an outer sheath layer outside the wrapping belt layer. Further, in step S1, the parts by weight of the ethylene-vinyl acetate copolymer, the inorganic flame retardant filler, the layered silicate and the carboxylated carbon nanotubes are 45-50 parts, 85-95 parts, 6-9 parts, and 1-3 parts, respectively. Further, the ethylene-vinyl acetate copolymer has a VA content of 25% to 30%; The inorganic flame-retardant filler adopts aluminum hydroxide or magnesium hydroxide with the average particle diameter D50 less than or equal to 1 mu m; the layered silicate is organized montmorillonite. In step S1, the carboxylated carbon nanotubes are ultrasonically dispersed in ethanol solution for 20-40min with a silane coupling agent accounting for 5-8% of the weight of the carboxylated carbon nanotubes before feeding, and subjected to surface pretreatment, the pretreated carbon nanotubes are premixed with a part of ethylene-vinyl acetate copolymer to prepare master batches, and finally the master batches, inorganic flame retardant filler, layered silicate and the rest of ethylene-vinyl acetate copolymer are fed into a double screw extruder. Further, the pretreated carbon nanotubes are premixed with ethylene-vinyl acetate copolymer accounting for 20 to 25 percent of the total amount of the ethylene-vinyl acetate copolymer to prepare master batch, and then are put into a double screw extruder together with inorganic flame retardant filler, layered silicate and ethylene-vinyl acetate copolymer accounting for 75 to 80 percent of the total amount of the ethylene-vinyl acetate copolymer. Further, in step S1, the functionalized insulating material satisfies: The microcosmic morphology of the functional insulating material is in the atomic force microscope conductive extension mode, in the observation area of 10 mu m multiplied by 10 mu m, the area occupied ratio average value of the largest continuous conductive clusters obtained through binarization treatment statistics is not more than 5%. Further, in step S4, the composite copper shielding la