Low-loss twisted-pair digital communication cable suitable for high-frequency vibration scene and preparation method and application of low-loss twisted-pair digital communication cable

Abstract

The invention discloses a low-loss twisted-pair digital communication cable suitable for a high-frequency vibration scene and a preparation method and application of the low-loss twisted-pair digital communication cable, and belongs to the technical field of cables. The cable comprises a silver-plated copper wire conductor, and a main insulating layer, a wire pair, a shielding layer and a sheath which are sequentially arranged from inside to outside. The main insulating layer is composed of a branch insulating layer and a plurality of hollow pipes which are distributed in parallel in a strip shape, and the contact area of the branch insulating layer and the hollow pipes is coated with a hot melt adhesive containing disulfide bonds. Each wire pair is formed by twisting two single wires, one single wire is provided with a spiral sawtooth-shaped protrusion, the other single wire is provided with a matched groove, the hot melt adhesive is filled in an attaching area, and rubber microspheres are filled in other gaps. The shielding layer comprises a double-sided composite aluminum foil, a braided shielding layer and a drain wire, and the sheath is made of a polyolefin nanocomposite material containing graphene. Through structure and material optimization, low-loss and high-stability transmission in a high-frequency vibration scene is realized, and the device is suitable for the fields of industrial automation, data centers and the like.

Description

Technical Field

[0001] The present invention belongs to the field of cable technology, and specifically relates to a low-loss twisted-pair digital communication cable suitable for high-frequency vibration scenarios, and a preparation method and application thereof. Background Art

[0002] As data rates increase to 40Gbps and above, higher requirements are placed on communication cables for high-frequency transmission performance, anti-interference capabilities, and structural stability. Traditional twisted-pair digital communication cables are gradually showing many shortcomings in meeting these requirements, making it difficult to meet the stringent standards of modern communication scenarios.

[0003] Specifically, the insulation layer of traditional cables mostly adopts a skin-foam-skin foam structure, which not only has a high dielectric constant (usually ≥1.8), resulting in large high-frequency dielectric attenuation, but also has weak lateral pressure resistance and more stringent requirements for production equipment. After the wire pairs are twisted, they are easily loosened due to external force, causing the center distance between the conductors to fluctuate, which in turn leads to unstable working capacitance, directly affecting key performance such as characteristic impedance and return loss.

[0004] Furthermore, in high-frequency vibration environments (vibration frequency 10-500Hz, amplitude 0.1-0.5mm), such as those experienced in industrial automation equipment, the hollow insulating tubes of traditional cables are prone to air leakage, wire pair "bite" failure, and shielding wear. These factors can degrade high-frequency transmission performance and make it impossible to reliably meet the requirements of 40Gbps high-speed transmission. Therefore, there is an urgent need for a twisted-pair digital communication cable that combines low loss, high stability, and vibration resistance. Summary of the Invention

[0005] The purpose of the present invention is to provide a low-loss twisted-pair digital communication cable suitable for high-frequency vibration scenarios, as well as its preparation method and application, so as to solve the problems of existing communication cables in high-frequency vibration environments, such as easy delamination between layers, easy displacement of microspheres, unstable characteristic impedance, and large return loss, so as to achieve stable and low-loss signal transmission of the cable under complex high-frequency vibration conditions, and meet the stringent requirements of industrial automation, high-end equipment manufacturing and other fields on the performance of communication cables.

[0006] The purpose of the present invention is achieved through the following technical solutions: A low-loss twisted-pair digital communication cable suitable for high-frequency vibration scenarios, comprising a conductor, a main insulation layer, a wire pair, a shielding layer, and a sheath; the conductor is a silver-plated copper wire; The main insulating layer includes a sub-insulating layer and a plurality of hollow tubes. The sub-insulating layer directly covers the outer surface of the conductor, and the plurality of hollow tubes are closely distributed in parallel strips on the outer edge of the sub-insulating layer to form a "multi-wrapped 1" structure. The sub-insulating layer material is a blend of irradiated cross-linked polyethylene (XLPE), polycarbonate (PC), polyolefin-g-polycaprolactone (where g is grafted, PO-g-PCL), disulfide-functionalized polyolefin, and ethylene-octene copolymer (POE). The hollow tube material is a blend of irradiated cross-linked polyethylene (XLPE), polymethylpentene (PMP), and nano-kaolin, with the inner wall coated with a modified polyolefin microfilm and gas vented inside. The contact area between the hollow tube and the sub-insulating layer is coated with a irradiated cross-linked polyethylene-based hot melt adhesive containing disulfide bonds. The wire pair is formed by twisting two structural single wires together, each single wire consisting of the conductor and a primary insulation layer wrapped around it; the outer surface of one of the single wires is provided with a continuous spiral sawtooth protrusion (formed by a plurality of parallel hollow tubes), and the outer surface of the other single wire is provided with a corresponding spiral sawtooth groove (formed by a plurality of parallel hollow tubes), the tooth shape and pitch of the protrusion and the groove matching each other (the protrusion and the groove are fully embedded); the contact area between the groove and the protrusion is filled with the radiation-crosslinked polyethylene-based hot melt adhesive containing disulfide bonds; The shielding layer is wrapped around the outside of the wire pair, including a double-sided composite aluminum foil, a braided shielding layer, and a drain wire. The double-sided composite aluminum foil is directly wrapped around the outer surface of the wire, and the braided shielding layer is braided with nickel-plated copper wire on the outside of the double-sided composite aluminum foil; the drain wire is arranged parallel to the inside of the braided shielding layer; The sheath is wrapped around the outside of the shielding layer, and the material is a polyolefin nanocomposite material containing graphene.

[0007] In the above scheme, the structural functions of the communication cable are as follows: The conductor uses silver-plated copper wire. The silver plating can reduce the skin effect during high-frequency signal transmission and reduce resistance loss. It is more suitable for the stable transmission of high-speed signals of 40Gbps and above than ordinary copper wire, laying the foundation for overall low-loss performance.

[0008] The main insulation layer forms a composite insulation system with a tightly wrapped inner layer and an outer layer support. The gas inside the hollow tube can form an air medium, reducing the dielectric loss of high-frequency transmission. At the same time, the hollow tube adds additional support to the sub-insulation layer, and its ability to resist lateral pressure is stronger than that of traditional foam insulation layers.

[0009] When the wire pairs are mated through the spiral serrated protrusions and grooves, the disulfide-bonded radiation-cross-linked polyethylene-based hot-melt adhesive filling the mating area provides secure fixation. The disulfide bonds in the hot-melt adhesive form dynamic covalent crosslinks with the radiation-cross-linked polyethylene in the hollow tube material and the disulfide-functionalized polyolefin in the sub-insulating layer. Under high-frequency vibration, these bonds break and reassemble to buffer stress, preventing wear or loosening at the mating point caused by rigid collisions. Simultaneously, the adhesive fills the tiny gaps between the mating surfaces of the protrusions and grooves, forming a sealing layer that reduces friction during vibration. Together with the rubber microspheres in other areas of the twist gap, the adhesive provides a synergistic effect of rigid fixation and elastic cushioning, ensuring the mating of the protrusions and grooves while absorbing vibration energy through the rubber microspheres. This resolves the dilemma of either brittle fracture due to overtightening or displacement due to overlooseness.

[0010] In the multi-layer shielding structure, double-sided composite aluminum foil is directly wrapped around the wire pairs to reflect low-frequency electromagnetic interference; the outer nickel-plated copper wire braided shield can block high-frequency interference, and the nickel plating layer can also improve corrosion resistance; the drain wire is fixed with a binding tape, which can quickly discharge the static electricity accumulated in the shielding layer to avoid electrostatic breakdown.

[0011] The sheath is made of a polyolefin nanocomposite material containing graphene, in which graphene is evenly dispersed in a polyolefin matrix. Graphene utilizes its high mechanical properties to enhance the sheath's impact and wear resistance while avoiding the formation of a continuous conductive path (maintaining insulation).

[0012] The functions of materials in communication cables are as follows: In the sub-insulating layer materials, XLPE provides basic insulation and temperature resistance, ensuring dielectric stability at high frequencies; PC enhances material rigidity and strengthens resistance to lateral pressure. However, the polar PC in the sub-insulating layer and the non-polar PMP in the hollow tube have poor compatibility, easily leading to delamination under long-term vibration and friction, which disrupts insulation continuity. PO-g-PCL acts as a molecular bridge. Its polar polycaprolactone side chains (containing ester groups) form intermolecular forces with the ester groups of PC. The non-polar polyolefin backbone interacts with the carbon chains of XLPE and hollow PMP, reducing the interfacial tension between PC and PMP, alleviating the interlayer repulsion caused by the polarity difference, and improving the compatibility of PC with XLPE and PMP. The disulfide-functionalized polyolefin in the sub-insulating layer and the disulfide-containing XLPE-based hot-melt adhesive coated on the hollow tube form initial covalent crosslinks, providing basic bonding strength for the interface between the sub-insulating layer and the hollow tube. However, in high-frequency vibration scenarios of 10-500Hz, relying solely on covalent crosslinking can easily cause fatigue fracture of the disulfide bonds. The addition of POE can absorb impact stress under high-frequency vibration with its own high elasticity, avoid irreversible fracture of disulfide bonds due to repeated stress impact, and synergistically maintain interlayer stability.

[0013] In the hollow tube, PMP has a low dielectric constant, which further reduces the dielectric loss of the main insulation layer, and adapts to high-frequency signal transmission; nano kaolin is uniformly dispersed in the substrate, which refines the material structure, improves the rigidity and wear resistance of the hollow tube, and improves the problem of pipe wall damage during vibration; XLPE and the XLPE substrate of the sub-insulation layer form a compatible basis, and the double sulfur bond hot melt adhesive further strengthens the interlayer bonding.

[0014] In the wire pair, the surface of the filled rubber microspheres is grafted with maleic anhydride grafted polyolefin, and the polar groups (-COOH) can form hydrogen bonds with the polar groups of the microspheres themselves (such as -F of fluororubber), and the non-polar chain segments are compatible with the polyolefin on the outer surface of the hollow tube, enhancing the interfacial adhesion of the microspheres and the hollow tube, reducing the risk of displacement of the rubber microspheres from the gap under high-frequency vibration due to weak interfacial adhesion.

[0015] In summary: the present application optimizes the structure and material of the cable, and realizes low loss and high stable transmission in high-frequency vibration environment.

[0016] As some embodiments of the present application, in the sub-insulation layer, the mass ratio of irradiation cross-linked polyethylene, polycarbonate, polyolefin-g-polycaprolactone, double sulfur bond functionalized polyolefin, and ethylene-octene copolymer is (3-4):1:(0.8-1.2):(0.02-0.03):(0.03-0.035).

[0017] In actual implementation, if the proportion of irradiation cross-linked polyethylene is too low, the temperature resistance and flexibility of the sub-insulation layer will decrease, and it is easy to become brittle; if the proportion of polycarbonate is too high, the polarity of the material will increase, and the interfacial repulsion with the hollow tube will increase; if PO-g-PCL is insufficient, it cannot effectively reduce the interfacial tension, which may cause delamination; and if the double sulfur bond functionalized polyolefin is too little, the dynamic cross-linking effect between the layers is weak, and the cable may still delaminate under vibration. Through the use amount provided by the present application, the irradiation cross-linked polyethylene can dominate the insulation and flexibility, the polycarbonate can moderately enhance the rigidity, the PO-g-PCL can fully play the compatibility role, and the double sulfur bond material can effectively form dynamic cross-linking, balancing the insulation performance, mechanical strength and interlayer stability.

[0018] As some embodiments of the present application, the thickness of the sub-insulation layer is 0.1-0.2mm; in the single wire with protrusions, the height of the spiral sawtooth protrusions is 0.03-0.05mm, which matches the groove depth in the single wire with grooves.

[0019] As some embodiments of the present application, in the hollow tube, the mass ratio of irradiation cross-linked polyethylene, polymethylpentene and nano kaolin is (6-7):(2-3):(0.007-0.009).

[0020] In actual implementation, if the proportion of polymethylpentene is too high, the material rigidity decreases, and the hollow tube is prone to deformation during coating. If the proportion is too low, the low dielectric strength advantage is insufficient and dielectric loss increases. Too much nano-kaolin can lead to increased material brittleness and easy cracking during vibration, while too little leads to weak reinforcement effect and insufficient wear resistance of the hollow tube. The parameters defined in the present invention allow polymethylpentene to fully exert its low dielectric effect, irradiated cross-linked polyethylene to ensure structural stability, and nano-kaolin to moderately enhance wear resistance, so that the hollow tube has a balance of low loss, rigidity, and durability.

[0021] As some possible implementation methods of the present application, the rubber microspheres are hydrogenated nitrile rubber / fluororubber blended microspheres, with a mass ratio of 7:(3-5); the diameter of the rubber microspheres is 0.01-0.12 mm.

[0022] In actual use, using only hydrogenated nitrile rubber (HNBR) can easily experience permanent compression set at high temperatures (e.g., 80°C), rendering it ineffective as a filler. Using only fluororubber (FKM) is costly and lacks elasticity at room temperature. Microspheres that are too large cannot fill small gaps, while those that are too small tend to aggregate, leading to dielectric inhomogeneity. Blended microspheres offer both room-temperature elasticity and high-temperature stability, making them suitable for wide-temperature vibration scenarios.

[0023] As some possible implementation methods of the present application, in the shielding layer, a polyimide film cushion layer with a thickness of 0.01-0.015 mm is provided between the double-sided composite aluminum foil and the braided shielding layer.

[0024] In practice, the thermal expansion difference between aluminum foil and nickel-plated copper wire is significant. Temperature fluctuations or vibrations can cause the foil to wrinkle or even tear due to stress, reducing shielding effectiveness. Without a backing layer, this thermal stress acts directly on the foil, increasing the risk of breakage. Polyimide film can mitigate the thermal expansion difference and reduce stress on the foil. The film's flexibility also absorbs vibration and shock, preventing tearing caused by direct friction between the foil and the braided wire, thus maintaining the integrity of the shielding layer.

[0025] As some possible implementation methods of the present application, in a single wire with protrusions, the surface area of ​​the hollow tube without the protrusions is provided with breathable micropores; in a single wire with grooves, the surface area of ​​the hollow tube without the grooves is provided with breathable micropores, the pore diameter of the breathable micropores is 500-800nm, distributed along the length of the single wire, and the pore spacing is 20-50mm; Adding polytetrafluoroethylene fiber grafted with maleic anhydride-acrylate copolymer to the hot melt adhesive filled in the twist gap of the wire pair (i.e., the groove and protrusion fitting); The double-sided composite aluminum foil is provided with micro-perforations with a diameter of 0.01-0.02 mm every 8-20 cm along the length direction, with a hole spacing of 3-15 mm and avoiding the drainage line fixing point; the binding tape is tied every 5-8 cm with a 0.8-1.2 cm gap left at the interval of 0.3-0.8 mm; the polyolefin nanocomposite material of the sheath is added with polytetrafluoroethylene fiber grafted with maleic anhydride-acrylate copolymer.

[0026] In practice, temperature fluctuations (such as sudden rises and falls in ambient temperature) or vibrations can cause pressure fluctuations within the hollow tube, causing the tube to expand or contract and affecting the stability of the dielectric constant. Without micropores, this pressure cannot be released, potentially causing the tube to rupture. Micropores allow trace amounts of gas to diffuse slowly, achieving dynamic pressure balance and reducing the impact of pressure fluctuations on the dielectric constant.

[0027] By adding polytetrafluoroethylene fibers to the hot melt adhesive at the junction of the protrusions and grooves, a gas guide channel can be formed to guide the diffusion of the leaking gas and prevent the gas from gathering at the twisted parts to form local high pressure; the surface grafting layer can enhance the compatibility of the fiber with the hot melt adhesive substrate and prevent the fiber from shifting under high-frequency vibration.

[0028] The micro-perforations of the double-sided composite aluminum foil, the angle adjustment of the braided shielding layer, and the intermittent fixing of the binding tape provide a discharge path for leaking gas, preventing it from accumulating in the shielding layer and causing wrinkles or tears in the aluminum foil. The polytetrafluoroethylene fibers added to the sheath are interwoven to form a continuous breathable network during the sheath extrusion process. The gaps between the fibers constitute gas outlet channels, which can quickly discharge the gas accumulated in the shielding layer to the outside, preventing the accumulation of air pressure inside the sheath from causing bulging.

[0029] These design features work together to maintain stable air pressure in the hollow tube despite temperature fluctuations and high-frequency vibrations, minimizing fluctuations in the dielectric constant of the main insulation layer. This also enhances the stability of the wire pair interlocking structure, shielding layer, and jacket, effectively resisting performance degradation under vibrations of 10-500Hz.

[0030] In addition, to achieve the above-mentioned object, the present invention also provides a method for preparing a low-loss twisted pair digital communication cable suitable for high-frequency vibration scenarios, comprising the following steps: S1. Wire drawing and conductor treatment: The copper wire is drawn and then silver plated; S2. Sub-insulating layer extrusion: Using a variable-speed screw extruder, a blend of irradiated cross-linked polyethylene, polycarbonate, polyolefin-g-polycaprolactone, disulfide-functionalized polyolefin, and ethylene-octene copolymer is extruded onto the outer surface of the conductor to form a sub-insulating layer. S3. Hollow tube preparation and primary insulation layer formation: S31 The irradiated cross-linked polyethylene, polymethylpentene and nano-kaolin blend, extruded through a multi-die co-extrusion process simultaneously strip hollow tube, extrusion into the tube when the gas, the inner wall coated with a modified polyolefin micro film; S32. The hollow tubes obtained in S31 are arranged parallel and closely on the outer edge of the sub-insulating layer of the two conductors, with the outer walls of adjacent hollow tubes in contact, and fixed to the bonding surface of the hollow tube and the sub-insulating layer by a irradiated cross-linked polyethylene hot melt adhesive containing disulfide bonds, forming a hollow tube integral structure coated on the outside of the sub-insulating layer; S33. The outer wall of the hollow tube structure outside one of the conductors is processed to form a continuous spiral serrated protrusion; the outer wall of the hollow tube structure outside the other conductor is processed to form a spiral serrated groove matching the tooth shape and pitch of the protrusion; ultimately forming two single wires with protrusions and grooves; S4. Wire Pair Twisting and Filling: Twist the raised wires and grooved wires at a preset pitch, ensuring the raised and grooved wires precisely align. Fill the joint area between the protrusions and grooves with irradiated cross-linked polyethylene hot melt adhesive containing disulfide bonds, and fill the area in the twisted gap where no protrusions or grooves are set with rubber microspheres grafted with maleic anhydride and polyolefin to ensure uniform filling; S5. Shielding layer processing: Wrap the double-sided composite aluminum foil online, lay the drain wire parallel to the outer surface of the double-sided composite aluminum foil (5), and then use a polyolefin spiral binding tape to bind the drain wire and the double-sided composite aluminum foil together; finally, braid the nickel-plated copper wire to form a braided shielding layer, so that the drain wire is wrapped inside the braided shielding layer; S6. Sheath extrusion: Extruding a graphene-containing polyolefin nanocomposite material onto the outer surface of the shielding layer to form a sheath; S7. Finished product inspection: inspect the cable’s characteristic impedance, return loss, and dielectric constant fluctuation after vibration.

[0031] The present invention can ensure that each structure is formed according to the design parameters by standardizing the processes such as conductor processing, main insulation layer preparation, and wire pair twisting in steps, thereby improving product consistency and stability and ensuring that performance meets the standards during mass production.

[0032] As some feasible embodiments of the present application, in step S2, the barrel temperature of the tapered screw extruder is controlled in three sections: 140-160°C in the feed section, 180-210°C in the melting section, and 210-230°C in the head section; and polyolefin-g-polycaprolactone and polycarbonate are first premixed to form a masterbatch, and then blended with irradiated cross-linked polyethylene, disulfide bond functionalized polyolefin, and ethylene-octene copolymer.

[0033] In practice, direct blending of polyolefin-g-polycaprolactone (PO-g-PCL) with polycarbonate (PC) can lead to uneven dispersion of the PO-g-PCL due to the significant difference in their dosages (PC as the primary component and PO-g-PCL as the additive), preventing it from fully functioning as a "molecular bridge." Three-stage temperature control ensures full melting and prevents degradation. Premixed masterbatches utilize the polar side chains of PO-g-PCL to pre-bond with the ester groups of PC, ensuring uniform dispersion of the compatibility additive throughout the PC. When subsequently blended with XLPE and disulfide-functionalized polyolefins, this effectively mitigates the polarity differences between PC and XLPE, preventing delamination of the insulating layer. Furthermore, direct blending of PO-g-PCL with XLPE, PC, and disulfide-functionalized materials without premixing to form a masterbatch can lead to insufficient dispersion due to the low dosage of PO-g-PCL. This can lead to increased interfacial repulsion between PC and XLPE, and facilitate delamination under vibration.

[0034] As some possible implementation methods of the present application, 0.5-1 wt % of ethylene-vinyl acetate copolymer is introduced into the sub-insulating layer as a toughening agent.

[0035] The significant hardness difference between PC and XLPE can easily lead to stress concentration at the interface at low temperatures. This, combined with vibration and shock, can cause embrittlement and cracking of the sub-insulation layer, compromising dielectric stability. The flexibility of EVA can mitigate this interfacial hardness difference between PC and XLPE, improving the low-temperature toughness of the sub-insulation layer, reducing the risk of embrittlement during low-temperature vibration, and maintaining insulation integrity.

[0036] To achieve the above-mentioned objectives, the present invention also provides the application of the communication cable in high-frequency vibration equipment, such as industrial robotic arms (such as robotic arms in automobile welding production lines), high-frequency vibration plate feeders (such as those used for sorting electronic components), and high-speed CNC milling machines (such as precision parts processing machines).

[0037] Compared with the prior art, the present invention has the following beneficial effects: By optimizing the cable's structure and materials, this invention achieves low-loss, highly stable transmission in high-frequency vibration scenarios. The "Multi-Wrap 1" main insulation layer, composed of a sub-insulating layer and a gas-filled hollow tube, combined with a low-dielectric material to form a semi-air dielectric, effectively addresses the high-frequency loss problem of traditional insulation layers. The silver-plated copper conductor reduces high-frequency skin effect losses, significantly improving high-frequency transmission performance (characteristic impedance stabilizes at 100±1 to 100±2Ω, and return loss reaches 26.3 to 28.7dB at 1GHz). It can stably support high-speed signal transmission of 40Gbps and above, and its high-frequency dielectric attenuation is far lower than that of traditional cables.

[0038] The compatibility design of disulfide bond dynamic cross-linking and polyolefin-g-polycaprolactone alleviates the polarity differences and thermal expansion stress of different materials, overcomes the risks of delamination and thermal stress cracking, and enables the cable to remain stable under temperature fluctuations of -30℃~80℃ (after high and low temperature cycle testing, there is no abnormality in the insulation layer and the rubber microspheres are not shifted. After high-temperature endurance testing, the sheath is intact, and the dielectric constant fluctuates by only 0.04~0.08), taking into account both temperature resistance and mechanical strength.

[0039] The wire pairs are twisted and engaged by the protrusions and grooves, and the rubber microspheres filled in the gaps form a dual fixation of "mechanical engagement + elastic buffering", ensuring structural stability during vibration and effectively resisting loosening caused by high-frequency vibration of 10-500Hz (after 100h of vibration at 10-500Hz and an amplitude of 0.3mm, the dielectric constant fluctuates by only 0.05-0.08, and the main insulation layer shows no cracking or delamination), solving the problems of wire pair engagement failure and fluctuation of conductor center distance under vibration in traditional cables.

[0040] In summary, the solution of the present invention accurately adapts to the transmission requirements of high-frequency vibration scenarios such as industrial automation and data centers, and achieves low-loss and highly stable signal transmission. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 : Schematic diagram of the structure of the low-loss twisted-pair digital communication cable in Example 1; Among them, 1-conductor, 2-insulation layer, 3-hollow tube, 4-wire pair, 5-composite aluminum foil, 6-drain wire, 7-braided shield layer, 8-sheath. DETAILED DESCRIPTION

[0042] Example 1 A low-loss twisted pair digital communication cable suitable for high-frequency vibration scenarios, such as Figure 1 As shown, it includes a conductor 1, a main insulation layer, a wire pair 4, a shielding layer and a sheath 8. The specific preparation method is as follows: S1. Wire Drawing and Conductor 1 Processing: The copper wire was drawn to a diameter of 0.8 mm and then silver-plated using an electroplating process. The silver layer had a thickness of 0.02 mm and an IACS conductivity of 105%.

[0043] S2. Extrusion of insulation layer 2: Material preparation: Irradiated cross-linked polyethylene (XLPE), polycarbonate (PC), polyolefin-g-polycaprolactone (PO-g-PCL), disulfide-functionalized polyolefin, and ethylene-octene copolymer (POE, elongation at break ≥800%) were weighed in a mass ratio of 3.5:1:1:0.025:0.035. PO-g-PCL and polycarbonate (PC) were first placed in a high-speed mixer and premixed at 100°C for 15 min to prepare a masterbatch. The masterbatch was then placed in a high-speed mixer together with XLPE, disulfide-functionalized polyolefin, and POE and stirred at 80°C for 10 min to form a blend.

[0044] Extrusion process: A variable speed screw extruder is used with the barrel temperature set at 160°C in the feed section, 210°C in the melting section, and 230°C in the die section. The blend is extruded onto the outer surface of conductor 1 at a controlled extrusion speed of 1.5 m / min. The blend is quickly shaped through a cooling water tank (water temperature 25°C), ultimately forming a sub-insulating layer 2 with a thickness of 0.2 mm (thickness deviation ≤ ± 0.01 mm).

[0045] S3. Preparation of hollow tube 3 and formation of the main insulation layer: S31. Material Blending and Tube Preparation: Irradiated cross-linked polyethylene, polymethylpentene, and nano-kaolin were blended in a mass ratio of 6.5:2.5:0.008. Ten hollow tubes (0.1 mm wall thickness) were simultaneously extruded through a 10-die coextrusion process. Air at 0.3 MPa was introduced into the tubes during extrusion. The inner walls were coated with a 0.005 mm thick modified polyolefin microfilm (not shown).

[0046] S32. Parallel Arrangement: Ten hollow tubes 3 were arranged parallel and closely together on the outer edge of the sub-insulating layer 2, with the outer walls of adjacent tubes touching. A single wire was formed by applying a radiation-crosslinked polyethylene-based hot-melt adhesive (50% solids content) containing disulfide bonds to the contact surface between the hollow tubes 3 and the sub-insulating layer 2. Two single wires were prepared using this method.

[0047] S33. Protrusion / Groove Processing (both common structures, not shown): For one of the single wires, its outer wall is integrated and machined according to a precise spiral trajectory, so that this set of hollow tubes 3 works together to form a continuous and complete spiral serrated protrusion (height 0.04mm). For the other single wire, a matching spiral serrated groove is machined on its outer wall, also following the spiral trajectory, ultimately forming two single wires with protrusions and grooves.

[0048] S4. 4-pair twist and fill: Two single wires with protrusions and grooves were twisted at a pitch of 15 mm to form 4 pairs of wires. A total of 4 pairs of wires with the same structure were prepared (e.g. Figure 1 ); During the twisting process, a precision glue injection device is first used to inject a disulfide bond-containing irradiated cross-linked polyethylene-based hot melt adhesive (solid content 50%) into the mating area between the protrusion and the groove to fill the tiny gap between the mating surfaces (glue layer thickness 0.002mm). After the hot melt adhesive was initially cured (placed at room temperature for 5 minutes), rubber microspheres (hydrogenated nitrile rubber / fluororubber mass ratio 7:4, diameter 0.04mm, surface grafted with maleic anhydride grafted polyolefin) were filled into the area of ​​the twisted gap where no protrusions and grooves were set. The filling volume accounted for 35% of the gap in this area; the four line pairs were arranged in parallel and in contact with each other.

[0049] S5. Shielding Fabrication: Wrap the wire pairs 4 with a double-sided composite aluminum foil 5 with a total thickness of 0.025mm. Lay a 0.3mm diameter copper drain wire 6 parallel to the outer surface of the double-sided composite aluminum foil 5. Use a 2mm wide polyolefin spiral binding tape to secure the drain wire 6 and the double-sided composite aluminum foil 5 together, tying them 1cm apart every 6cm, leaving a 0.5mm gap at intervals. Finally, braid 36 strands of nickel-plated copper wire to form a braided shield 7 (braid density 92%), encasing the drain wire 6 inside the braided shield 7.

[0050] S6. Sheath 8 extrusion: Material Preparation: Graphene was added to a polyolefin matrix (linear low-density polyethylene, melt flow rate 2.0 g / 10 min) at a graphene to polyolefin mass ratio of 1:80. Ultrasonic dispersion (500 W, 30 min, anhydrous ethanol as the dispersion medium) was performed, followed by vacuum drying to produce a graphene masterbatch. This masterbatch was then melt-sheared in a twin-screw extruder at 140-150°C and a screw speed of 250 rpm to form a sheath composite material that can be directly extruded.

[0051] Extrusion process: The composite material is extruded on the outside of the shielding layer to form a sheath 8 with a thickness of 1.0 mm.

[0052] S7. Finished product inspection: inspect characteristic impedance, return loss, and dielectric constant fluctuation after vibration.

[0053] Example 2 Compared with Example 1, there are the following differences: S3. Preparation of Hollow Tube 3 and Formation of Primary Insulation Layer: Weigh materials in a mass ratio of 6:2:0.007 and extrude a tube blank (through aeration with 0.25 MPa air).

[0054] S4. 4-pair twist and filling: Single-pair twist pitch 12mm, filled with rubber microspheres (hydrogenated nitrile rubber / fluororubber 7:3, diameter 0.04mm), filling volume accounting for 30%.

[0055] S5. Shielding layer processing: Aluminum foil thickness 0.02mm, braided shielding layer 7 density 90%, drain wire 6 fixed in the same manner as in Example 1.

[0056] The remaining steps or parameters are the same as those in Example 1.

[0057] Example 3 Compared to Example 1, in step S2, 0.8 wt% of ethylene-vinyl acetate copolymer was introduced into the material of the sub-insulating layer 2 and then blended with other materials before extrusion. The remaining steps were the same as in Example 1.

[0058] Example 4 Compared to Example 3, in step S5, a 0.012 mm thick polyimide film cushion layer (not shown) is added between the double-sided composite aluminum foil 5 and the braided shielding layer 7. The cushion layer is provided in a spiral wrapping manner with a wrapping overlap ratio of 15%. The remaining steps are the same as in Example 3.

[0059] Example 5 Compared with Example 3, steps S3, S4, S5, and S6 are adjusted as follows, and the remaining steps are the same as Example 3: S3: After preparing both protruding and grooved single wires, ventilation micropores were created in the unprocessed protrusions or grooves of the hollow tube 3. These micropores were drilled using precision laser drilling equipment (not shown). The micropores had a diameter of 500 nm and were distributed along the length (axial direction) of the single wire, with a spacing of 25-35 mm (ensuring approximately 30-40 micropores per meter of single wire, avoiding the protrusions / grooves). The micropores penetrated the modified polyolefin microfilm on the wall and inner surface of the hollow tube 3, replacing the air inside the hollow tube 3 with xenon gas.

[0060] S4. 4-pair twist and fill: The two single wires prepared in S3 are twisted at a pitch of 15 mm to form a wire pair 4, and a total of 4 wire pairs 4 with the same structure are prepared (such as Figure 1 ); During the twisting process, a precision glue injection device is first used to inject a disulfide bond-containing irradiated cross-linked polyethylene hot melt adhesive [solid content 50%, and added with 0.45wt% polytetrafluoroethylene short fibers, the short fibers are 30-50μm long, 1-2μm in diameter, and surface-grafted with maleic anhydride-acrylate copolymer (grafting rate 1.2-1.3%), aspect ratio 20-30:1) into the fitting area between the protrusion and the groove to fill the tiny gap on the fitting surface (glue layer thickness 0.002mm).

[0061] After the hot melt adhesive was initially cured (placed at room temperature for 5 minutes), rubber microspheres (hydrogenated nitrile rubber / fluororubber mass ratio 7:4, diameter 0.04mm, surface grafted with maleic anhydride grafted polyolefin) were filled into the area of ​​the twisted gap where no protrusions and grooves were set. The filling volume accounted for 35% of the gap in this area; the four line pairs were arranged in parallel and in contact with each other.

[0062] S5. Shielding Processing: Wrap the wire pairs 4 with a double-sided composite aluminum foil 5 having a total thickness of 0.025mm. Micro-perforations (not shown) with a diameter of 0.015mm are provided every 15cm along the length of the aluminum foil, with a spacing of 8mm between the holes. Lay a 0.3mm diameter copper drain wire 6 parallel to the outer surface of the double-sided composite aluminum foil 5, ensuring that the drain wire 6 avoids the micro-perforations in the aluminum foil. Use polyolefin spiral binding tape (not shown) to secure the drain wire 6 to the double-sided composite aluminum foil 5, tying them 1cm apart every 6cm, with a 0.5mm gap at intervals. Finally, form a braided shield 7 (92% braid density) using 36 strands of nickel-plated copper wire at a 50° braid angle, encasing the drain wire 6 inside the braided shield 7.

[0063] S6. Sheath 8 extrusion: Graphene was added to a polyolefin substrate (linear low-density polyethylene, melt flow rate 2.0 g / 10 min) at a mass ratio of 1:80. The graphene was then ultrasonically dispersed (power 500 W, time 30 min, dispersion medium anhydrous ethanol, and vacuum drying after ultrasonication to remove the medium) to produce a graphene masterbatch. Polytetrafluoroethylene short fibers (length 200-300 μm, diameter 10-15 μm, surface grafted with maleic anhydride-acrylate copolymer, grafting rate 1.2-1.5%) and graphene masterbatch were premixed in a high-speed mixer (mixing temperature 70°C, speed 300 r / min, mixing time 15 min) at a mass ratio of 0.015:1 to produce a PTFE-graphene composite masterbatch. The composite masterbatch was then directly fed into a twin-screw extruder and melt-sheared at a temperature of 140-150°C and a screw speed of 250 r / min to form a sheath composite material that can be directly extruded.

[0064] Extrusion process: The composite material is extruded on the outside of the shielding layer to form a sheath 8 with a thickness of 1.0 mm.

[0065] It is worth noting that in the above embodiments, the preparation methods of some materials are as follows: ① Polyolefin-g-polycaprolactone: In a dry environment under argon, add 500 mL of toluene to a 1000 mL polymerization reactor, followed by 12 mM 1-hexene monomer. Stir for 5 minutes to evenly disperse the monomers, and adjust the reaction temperature to 60°C. Add 0.1 mL of 0.5 mol / L triisobutylaluminum as a chain transfer agent, followed by a 1 mM toluene solution of (Ph3C)(B(C6F5)4), and finally a 0.5 mM toluene solution of 2-(N-(2,4,6-trimethylphenylimino)-o-isopropylphenyl-methyl)-6-(2-η-1-naphthyl)-pyridinedimethylzirconium catalyst. Polymerization was carried out with stirring for 2 minutes to produce polyolefin segments. Next, add 5 mM 3-methyl-caprolactone monomer to the reaction solution, raise the temperature to 85°C, and conduct ring-opening polymerization for 12 hours. After the reaction is completed, the solution is poured into ethanol for precipitation, filtered, washed, and dried under vacuum to finally obtain polyolefin-g-polycaprolactone.

[0066] ② Disulfide-functionalized polyolefin: In a dry 500 mL reaction flask, add 0.5 g of cis-2-butene-1,4-dithioacetate (CTA-1), 0.01 g of Grubbs' third-generation catalyst (G3), and 20 g of cyclooctene (COE). Add 100 mL of dichloromethane (DCM) and stir to dissolve. The molar ratio of CTA-1 to G3 is 100:1, and the COE concentration is 2.0 M. After stirring at 25°C for 4 h, the reaction solution is poured into a five-fold volume of cold methanol for precipitation. The solid is collected by filtration and dried under vacuum at 40°C for 6 h to obtain the disulfide-functionalized polyolefin.

[0067] ③ Maleic anhydride-grafted polyolefin rubber microspheres: 70g of hydrogenated nitrile rubber and 30g of fluororubber (the amounts used here are those in Example 1; adjust the amounts in Example 2 based on the actual amounts) were mixed on a two-roll mill at 120°C for 10 minutes. After crushing, 200mL of toluene was added to dissolve the mixture into a rubber solution. The solution was spray-dried (inlet air temperature 120°C, outlet air temperature 60°C) to form microspheres with a diameter of 0.04mm. Separately, 5g of maleic anhydride-grafted polyolefin was dissolved in 100mL of toluene. The microspheres were added and stirred at 60°C for 2 hours. After filtration, the mixture was vacuum-dried at 50°C for 4 hours to obtain the grafted microspheres.

[0068] The preparation method of maleic anhydride grafted polyolefin is as follows: 100g of polyolefin (such as polyethylene), 5g of maleic anhydride, and 0.2g of dicumyl peroxide are added to a twin-screw extruder, the feed section temperature is 140°C, the melting section temperature is 160°C, the head section temperature is 170°C, and the screw speed is 200r / min, and the maleic anhydride grafted polyolefin is obtained by melt blending, extrusion and granulation.

[0069] ④ XLPE-based hot melt adhesive containing disulfide bonds: Add 80 parts of irradiated cross-linked polyethylene (XLPE), 5 parts of diallyl disulfide, 15 parts of C5 petroleum resin, and 0.5 parts of antioxidant 1010 to a high-speed mixer and mix at 80°C for 10 minutes. The mixture is then fed into a twin-screw extruder (feed section 140°C, melt section 160°C, die section 170°C), melt-blended, and extruded into pellets. Heat and melt to a solids content of 50% before use.

[0070] ⑤ Modified polyolefin microfilm: 95g of low-density polyethylene (LDPE) and 5g of maleic anhydride-modified polyethylene were added to a twin-screw extruder, melt-blended at 160°C, and extruded into a film through a T-die. The film was then biaxially stretched (longitudinal stretching ratio 3:1, transverse stretching ratio 3:1) to control the thickness to 0.005mm to obtain a modified polyolefin microfilm.

[0071] (6) Polyolefin spiral binding tape: 60 g of linear low-density polyethylene, 35 g of magnesium hydroxide, 2 g of silane coupling agent KH550, and 0.5 g of antioxidant 168 were added into a high-speed mixer and mixed at 100°C for 15 min. The mixture was granulated by a twin-screw extruder (feed section 150°C, melting section 170°C, die section 180°C), and then extruded by a spiral forming die (temperature 170°C) with a width of 2 mm. After cooling, the product was wound up to obtain the polyolefin spiral binding tape.

[0072] (7) Ethylene-vinyl acetate copolymer (EVA): 82 g of ethylene monomer, 18 g of vinyl acetate monomer, and 0.2 g of dicumyl peroxide (initiator) were added into a high-pressure reaction kettle. After nitrogen replacement for 3 times, the temperature was raised to 200°C, the pressure was increased to 200 MPa, and the reaction was stirred for 4 h. After pressure reduction and cooling, the product was granulated by a pelletizer to obtain EVA.

[0073] (8) Double-sided composite aluminum foil 5: two 0.0125 mm thick aluminum foils were taken, and an acrylic adhesive (solid content 30%) was uniformly coated on one of the surfaces at a coating amount of 5 g / m 2 . The coated aluminum foil was dried in an oven at 80°C for 30 seconds. The other aluminum foil was laminated with the coated surface, and the lamination was completed by a pressure roller with a pressure of 0.3 MPa. After winding, a double-sided composite aluminum foil 5 with a total thickness of 0.025 mm was obtained.

[0074] (9) Irradiation cross-linked polyethylene: in an argon-protected dry environment, 500 mL of toluene was added into a 1000 mL polymerization reactor, followed by the addition of 12 mM of linear low-density polyethylene raw material, stirring for 6 min, and adjusting the reaction temperature to 60°C. 0.1 mL of triisobutylaluminum with a concentration of 0.5 mol / L was added as a chain transfer agent, followed by the addition of 1 mM of (Ph3C)(B(C6F5)4) toluene solution, and finally 0.5 mM of 2-(N-(2,4,6-trimethylphenylimine)-o-isopropylphenyl-methyl)-6-(2-η-1-naphthyl)-pyridine dimethyl zirconium catalyst toluene solution was added, stirring for 2 min. The reaction product was then transferred to a twin-screw extruder for extrusion and granulation. Finally, an electron accelerator was used for irradiation treatment with an electron beam energy of 2.0 MeV and an irradiation dose of 200 kGy. Argon was filled during the irradiation process to form irradiation cross-linked polyethylene.

[0075] The materials whose preparation methods are not specified are commercially available materials.

[0076] Comparative Example 1 Compared with Example 1, step S3 is omitted. Only step S2 is used to extrude a 0.3 mm thick sub-insulation layer 2 (the same material as in Example 1) outside the conductor 1, and then step S4 is directly used for twisting. The remaining steps are the same as in Example 1.

[0077] Comparative Example 2 Compared with Example 1, in step S2, the material of the sub-insulating layer 2 does not contain PO-g-PCL. The remaining steps are the same as in Example 1.

[0078] Comparative Example 3 Compared with Example 1, In step S2, the material of the sub-insulating layer 2 does not contain disulfide functionalized polyolefin; In step S3, ordinary XLPE hot melt adhesive (without disulfide bonds) is applied when the hollow tube 3 is covered with the sub-insulating layer 2.

[0079] The remaining steps are the same as in Example 1.

[0080] Comparative Example 4 Compared to Example 1, in step S2, PO-g-PCL and disulfide functionalized polyolefin were not pre-mixed as masterbatches, but were directly fed into the extruder for blending with XLPE, disulfide functionalized polyolefin, and POE. The remaining steps were the same as in Example 1.

[0081] Comparative Example 5 Compared with Example 5, polytetrafluoroethylene fiber is not added to the hot melt adhesive. The remaining steps are the same as Example 5.

[0082] Experimental example The twisted pair digital communication cables prepared in Examples 1-5 and Comparative Examples 1-5 were subjected to the following tests: 1. Basic high-frequency performance.

[0083] Characteristic impedance: Frequency range 100MHz-1GHz, test environment temperature 23±2℃, relative humidity 50±5%, measured using a vector network analyzer with a sampling interval of 10MHz (according to IEC 61156-5 standard); Return loss: Test frequency: 1 GHz. Test environment: same as characteristic impedance test. Before testing, the cable shall be kept at a constant temperature (23±2°C) for 24 hours. The average measured value of the full length of the cable (100m) shall be taken (according to IEC 61156-5 standard).

[0084] 2. Post-vibration performance.

[0085] Vibration conditions: 10-500Hz, amplitude 0.3mm, 100 hours duration (according to GB / T2423.10 standard, implementing sinusoidal vibration test, sweep rate 1oct / min, and dwelling at each frequency point for 5 minutes); Test indicators: Dielectric constant fluctuation after vibration (tested according to GB / T 1409 standard at a frequency of 1MHz, with the absolute value of the fluctuation calculated based on the initial dielectric constant before vibration), and the status of sub-insulation layer 2 (the status of sub-insulation layer 2 directly reflects the overall stability of the main insulation layer; cracking or delamination will lead to a loss of insulation continuity in the main insulation layer) or the shielding layer. The status inspection mainly checks for delamination / cracking, etc., and is observed using a metallographic microscope at a magnification of 200x.

[0086] 3. Temperature adaptability test.

[0087] ① High and low temperature cycle: -30℃ (maintain for 2 hours) → 80℃ (maintain for 2 hours), cycle 50 times.

[0088] Test indicators: The state of the insulation layer 2 after cycling (can be observed with a metallographic microscope at 200x magnification, and the judgment standard is the same as the state of the insulation layer after vibration), the displacement of the microspheres filled in line pair 4 (observed with a metallographic microscope, a displacement distance of ≤0.01mm is considered stable); ② High temperature and long-lasting: placed at a constant temperature of 80℃ for 1000 hours.

[0089] Test indicators: Dielectric constant fluctuation after endurance test (based on the initial dielectric constant before high-temperature endurance test, test frequency 1MHz, absolute value of fluctuation difference, according to GB / T 1409 standard), sheath 8 cracking (visual observation combined with 50x microscope observation).

[0090] The test results are shown in Table 1.

[0091] Table 1: It can be seen from Table 1 that the twisted pair digital communication cables prepared in Examples 1-5 showed excellent comprehensive performance in various tests. In terms of basic high-frequency performance, the characteristic impedance is stably controlled within a certain range, and the return loss value is good, which ensures low loss and high efficiency of the signal in high-frequency transmission. In the face of a vibration environment, the dielectric constant fluctuates less after vibration, and the structure of the insulating layer 2 and the shielding layer is stable, without cracking, delamination and other undesirable phenomena. In the temperature adaptability test, whether it is a high and low temperature cycle or a high temperature endurance test, the sheath 8 remains intact, the wire pair 4 is filled with microspheres without displacement, and the dielectric constant fluctuation is maintained at a low level, indicating that the cable can maintain stable performance under complex temperature conditions and meet the requirements of actual applications.

[0092] Next, the embodiments and comparative examples are specifically analyzed: Example 1-2: Through structural and material optimization, characteristic impedance was controlled, resulting in low return loss. Excellent performance in vibration and temperature tests effectively mitigated the effects of external stress and temperature changes. Example 3: The introduction of an EVA toughening agent significantly improved the temperature resistance of the sub-insulating layer 2. During high- and low-temperature cycling tests, the sub-insulating layer 2 showed no signs of embrittlement and maintained good performance across other indicators, demonstrating the effectiveness of the EVA toughening agent in enhancing the toughness of the sub-insulating layer 2 and improving the overall temperature adaptability of the cable.

[0093] Example 4: Adding a polyimide film underlayment significantly improved the shield's performance. During vibration testing, the shield showed no tearing and further reduced return loss, demonstrating that the underlayment effectively reduced friction and stress concentration between the shield and other components, improving the shield's stability and signal transmission quality. Example 5: The addition of breathable micropores performed particularly well in the temperature adaptability test, effectively balancing the air pressure fluctuations caused by temperature changes. This allowed the cable to undergo minimal fluctuations in dielectric constant during high-temperature endurance and high-low temperature cycle tests, while the sheath 8 and internal structure remained stable, demonstrating the design's good adaptability to extreme temperature environments. Comparative Example 1: The hollow tube 3 is missing, and the sub-insulating layer 2 lacks sufficient support during vibration and temperature changes, resulting in a decrease in the ability to resist lateral pressure, prone to cracking, and a significant attenuation of high-frequency performance. Comparative Example 2: PO-g-PCL compatibilizer was not used, resulting in poor interface compatibility between PC and PMP and other materials. Under vibration, the sub-insulating layer 2 was prone to delamination, affecting the performance of the cable. Comparative Example 3: A dynamic crosslinking system constructed without disulfide bond materials relies solely on physical bonding between layers. Under vibration and temperature stress, insufficient interlayer adhesion leads to localized delamination of the insulation layer 2 and performance degradation. This demonstrates the importance of dynamic crosslinking technology in enhancing interlayer bonding and improving cable structural stability. Comparative Example 4: PO-g-PCL and the disulfide bond material were not pre-mixed into a masterbatch, resulting in uneven dispersion of the materials in the cable system and large fluctuations in the performance of the sub-insulating layer 2. Comparative Example 5: After reducing the polytetrafluoroethylene fiber in the hot melt adhesive, the gas cannot be discharged, and the accumulated gas destroys the disulfide bond crosslinking between the hot melt adhesive and the hollow tube 3.

[0094] In summary: The technical solutions proposed in the present invention, such as structural optimization, material innovation, and process control, have a significant effect on improving the performance of twisted-pair digital communication cables under high-frequency vibration and complex temperature environments, and provide reliable technical support for the application of twisted-pair digital communication cables in actual complex environments.

Claims

1. A low-loss twisted pair digital communication cable suitable for high-frequency vibration scenarios, comprising a conductor (1), a main insulation layer, a wire pair (4), a shielding layer, and a sheath (8); characterized in that: The conductor (1) is a silver-plated copper wire; The main insulating layer comprises a sub-insulating layer (2) and a plurality of hollow tubes (3), wherein the sub-insulating layer (2) is directly coated on the outer surface of the conductor (1), and the plurality of hollow tubes (3) are closely distributed on the outer edge of the sub-insulating layer (2) in a parallel strip distribution manner, forming a "multi-wrapped 1" structure; The sub-insulating layer (2) is made of a blend of irradiated cross-linked polyethylene, polycarbonate, polyolefin-g-polycaprolactone, disulfide-functionalized polyolefin, and ethylene-octene copolymer; the hollow tube (3) is made of a blend of irradiated cross-linked polyethylene, polymethylpentene, and nano-kaolin, the inner wall of which is coated with a modified polyolefin microfilm and gas is passed through the interior; the contact area between the hollow tube (3) and the sub-insulating layer (2) is coated with a irradiated cross-linked polyethylene-based hot melt adhesive containing disulfide bonds; The wire pair (4) is formed by twisting a single wire with a protrusion and a single wire with a groove, each single wire being composed of the conductor (1) and a main insulating layer wrapped around the outer side thereof; the outer surface of the single wire with the protrusion is provided with continuous spiral sawtooth protrusions, and the outer surface of the single wire with the groove is correspondingly provided with spiral sawtooth grooves, and the tooth shape and pitch of the protrusion and the groove match; the bonding area between the groove and the protrusion is filled with the irradiated cross-linked polyethylene-based hot melt adhesive containing disulfide bonds; The twist gap of line pair (4) is not provided with projections and grooves and is filled with rubber microspheres grafted with maleic anhydride grafted with polyolefin; The shielding layer is wrapped around the outside of the wire pair (4), and includes a double-sided composite aluminum foil (5), a braided shielding layer (7), and a drain wire (6). The double-sided composite aluminum foil (5) is directly wrapped around the outer surface of the wire pair (4), and the braided shielding layer (7) is braided with nickel-plated copper wire on the outside of the double-sided composite aluminum foil (5); the drain wire (6) is arranged parallel to the inside of the braided shielding layer (7); The sheath (8) is wrapped around the outside of the shielding layer, and the material is a polyolefin nanocomposite material containing graphene.

2. The low-loss twisted pair digital communication cable suitable for high-frequency vibration scenarios according to claim 1, characterized in that: In the sub-insulating layer (2), the mass ratio of irradiated cross-linked polyethylene, polycarbonate, polyolefin-g-polycaprolactone, disulfide functionalized polyolefin, and ethylene-octene copolymer is (3-4):1:(0.8-1.2):(0.02-0.03):(0.03-0.035).

3. The low-loss twisted pair digital communication cable suitable for high-frequency vibration scenarios according to claim 1, characterized in that: The thickness of the sub-insulating layer (2) is 0.1-0.2 mm; in the single wire with protrusions, the height of the spiral sawtooth protrusions is 0.03-0.05 mm, matching the depth of the grooves in the single wire with grooves.

4. The low-loss twisted pair digital communication cable suitable for high-frequency vibration scenarios according to claim 1, characterized in that: In the hollow tube (3), the mass ratio of irradiated cross-linked polyethylene, polymethylpentene and nano-kaolin is (6-7): (2-3): (0.007-0.009).

5. The low-loss twisted-pair digital communication cable suitable for high-frequency vibration scenarios according to claim 1, characterized in that: The rubber microspheres are hydrogenated nitrile rubber / fluororubber blended microspheres, with a mass ratio of 7:(3-5); the diameter of the rubber microspheres is 0.01-0.12 mm.

6. The low-loss twisted pair digital communication cable suitable for high-frequency vibration scenarios according to claim 1, characterized in that: In the shielding layer, a polyimide film cushion layer with a thickness of 0.01-0.015 mm is provided between the double-sided composite aluminum foil (5) and the braided shielding layer (7).

7. The low-loss twisted pair digital communication cable suitable for high-frequency vibration scenarios according to claim 1, characterized in that: In the single wire with protrusions, the surface area of ​​the hollow tube (3) without processing the protrusions is provided with air-permeable micropores; in the single wire with grooves, the surface area of ​​the hollow tube (3) without processing the grooves is provided with air-permeable micropores; the diameter of the air-permeable micropores is 500-800nm, distributed along the length direction of the single wire, and the hole spacing is 20-50mm; Adding polytetrafluoroethylene fiber grafted with maleic anhydride-acrylate copolymer to the hot melt adhesive filled in the twisted gap of the line pair (4); The double-sided composite aluminum foil (5) is provided with micro-perforations with a diameter of 0.01-0.02 mm every 8-20 cm along the length direction, with a hole spacing of 3-15 mm and avoiding the fixed position of the drainage line (6); the binding tape is tied every 5-8 cm with a 0.8-1.2 cm gap and a 0.3-0.8 mm gap is left at the interval; Polytetrafluoroethylene fibers grafted with maleic anhydride-acrylate copolymer are added to the polyolefin nanocomposite material of the sheath (8).

8. The method for preparing a low-loss twisted pair digital communication cable suitable for high-frequency vibration scenarios according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1. Wire drawing and conductor treatment: The copper wire is drawn and then silver plated; S2. Extrusion of the sub-insulating layer (2): using a variable speed screw extruder, extruding a blend of irradiated cross-linked polyethylene, polycarbonate, polyolefin-g-polycaprolactone, disulfide functionalized polyolefin, and ethylene-octene copolymer onto the outer surface of the conductor (1) to form the sub-insulating layer (2); S3. Preparation of hollow tube (3) and formation of primary insulation layer: S31. The irradiated cross-linked polyethylene, polymethylpentene and nano-kaolin are blended and extruded into a hollow strip tube (3) through a multi-die co-extrusion process. During extrusion, gas is introduced into the tube and the inner wall is coated with a modified polyolefin microfilm. S32. The hollow tubes (3) obtained in S31 are respectively and closely arranged parallel to the outer edges of the sub-insulating layers (2) of the two conductors, with the outer walls of adjacent hollow tubes (3) in contact, and fixed to the bonding surfaces of the hollow tubes (3) and the sub-insulating layers (2) by means of a radiation-crosslinked polyethylene-based hot melt adhesive containing disulfide bonds, thereby forming an overall hollow tube structure wrapped around the sub-insulating layers; S33. The outer wall of the hollow tube (3) outside one of the conductors is processed to form a continuous spiral serrated protrusion; the outer wall of the hollow tube (3) outside the other conductor is processed to form a spiral serrated groove matching the tooth shape and pitch of the protrusion; and finally, two single wires with protrusions and grooves are formed; S4. Wire Pair Twisting and Filling: Twist the raised wires and grooved wires at a preset pitch, ensuring the raised and grooved wires precisely align. Fill the joint area between the protrusions and grooves with irradiated cross-linked polyethylene hot melt adhesive containing disulfide bonds, and fill the area in the twisted gap where no protrusions or grooves are set with rubber microspheres grafted with maleic anhydride and polyolefin to ensure uniform filling; S5. Shielding layer processing: Wrap the double-sided composite aluminum foil (5) around the wire pair (4), then lay the drain wire (6) parallel to the outer surface of the double-sided composite aluminum foil (5), and then use a polyolefin spiral binding tape to bind the drain wire (6) and the double-sided composite aluminum foil (5) together; finally, braid the nickel-plated copper wire to form a braided shielding layer (7); S6. Sheath extrusion: extruding a graphene-containing polyolefin nanocomposite material onto the outside of the shielding layer to form a sheath (8); S7. Finished product inspection: inspect the cable’s characteristic impedance, return loss, and dielectric constant fluctuation after vibration.

9. The method for preparing a low-loss twisted pair digital communication cable suitable for high-frequency vibration scenarios according to claim 8, characterized in that: In step S2, the barrel temperature of the tapered screw extruder is controlled in three sections: 140-160°C in the feed section, 180-210°C in the melt section, and 210-230°C in the die section; and polyolefin-g-polycaprolactone and polycarbonate are first premixed to form a masterbatch, which is then blended with irradiated cross-linked polyethylene, disulfide-functionalized polyolefin, and ethylene-octene copolymer.

10. Use of the communication cable according to any one of claims 1 to 7 in high-frequency vibration equipment.

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