Fireproof carbon fiber composite cable core and preparation method thereof

Abstract

This invention belongs to the technical field of carbon fiber cable cores, specifically disclosing a fire-resistant carbon fiber composite cable core and its preparation method. The preparation method includes the following steps: S1, preparing carbon fiber microrods with a diameter of 0.5~1.5mm; S2, preparing an interface functional layer: plasma treatment, followed by sequential coating to form an elastic reset layer and impregnation coating to form a microparticle friction layer; S3, bundling 19~61 carbon fiber microrods in parallel; S4, stranding a composite load-bearing core with tin-plated copper wire; S5, preparing a fire-resistant isolation layer and an insulating protective layer: wrapping with mica tape and fiberglass tape to form a fire-resistant isolation layer, then extruding a low-smoke halogen-free flame-retardant material after heating and melting it to form an insulating protective layer. This invention, using the above-mentioned fire-resistant carbon fiber composite cable core and its preparation method, improves the electrical integrity and resistance to fretting wear of the cable core under high temperature and fire conditions, while also improving the stability of mass production.

Description

Technical Field

[0001] This invention relates to the field of carbon material cable core technology, and in particular to a fire-resistant carbon fiber composite cable core and its preparation method. Background Technology

[0002] In critical sectors such as power transmission, rail transportation, petrochemical industry, and tunnel engineering, cables not only need stable conductivity but also must withstand extreme conditions such as high temperatures and fires. Fire resistance integrity and interfacial mechanical stability are key indicators determining the safe operation of cable cores. Traditional cable cores often use steel cores or metal load-bearing structures, which have drawbacks such as high specific gravity and significant magnetic loss. Under continuous high temperatures and cyclic loads, they are prone to increased sag and excessive residual elongation, affecting service life and operational safety.

[0003] In existing technologies, carbon fiber reinforced composite load-bearing cores are increasingly being used to address the aforementioned problems. However, the interface between the composite load-bearing core and surrounding layers is prone to micro-slippage and fretting wear under temperature-load coupling, and the coefficient of friction drifts with temperature. Fire-resistant structures rely on mica / glass fiber and silicone rubber, which are susceptible to interlaminar shear and end slippage under mechanical coupling and thermal shock conditions, making it difficult to maintain circuit integrity for extended periods during a fire, indicating an unreasonable fire-resistant structural design. Therefore, the interface compatibility between the core and conductor / protective layers, as well as the fire-resistant structure's resistance to failure, still need improvement.

[0004] Therefore, developing a fire-resistant carbon fiber composite cable core and its preparation method has become an urgent technical problem to be solved in this field. Summary of the Invention

[0005] The purpose of this invention is to provide a fire-resistant carbon fiber composite cable core and its preparation method, which improves the electrical integrity and resistance to fretting wear of the cable core under high temperature and fire conditions, while also improving the stability of mass production.

[0006] To achieve the above objectives, the present invention provides a method for preparing a fire-resistant carbon fiber composite cable core, comprising the following steps: S1. Preparation of carbon fiber microrods: Carbon fiber bundles are impregnated with a resin matrix and pultruded through a mold to obtain carbon fiber microrods with a diameter of 0.5~1.5mm; S2. Preparation of interface functional layer: Plasma treatment is performed on the surface of the carbon fiber microrod obtained in S1, and then an elastic reset layer and a micro-particle friction layer are sequentially coated on the surface of the carbon fiber microrod to obtain the carbon fiber microrod with interface functional layer. S3. Bundling to form a composite load-bearing core: The carbon fiber microrods obtained in S2 are bundled together in parallel using a bundling machine to obtain a composite load-bearing core. This number of carbon fiber microrods can ensure uniform load-bearing capacity and structural stability. The diameter of a single carbon fiber microrod is 0.5~1.5mm, which can ensure sufficient mechanical strength while taking into account the flexibility of the core. S4. Preparation of conductor layer: The composite load-bearing core obtained in S3 and the tin-plated copper wire are twisted together to form a conductor layer; S5. Preparation of fireproof isolation layer and insulating protective layer: Mica tape and fiberglass tape are used for wrapping. The overlapping of mica tape and fiberglass tape can form a stable heat insulation barrier at high temperature, blocking the spread of flames and forming a fireproof isolation layer. Then, low smoke halogen-free flame retardant material is heated and melted and extruded on the outside of the fireproof isolation layer to form an insulating protective layer. In case of fire, it can expand to form a dense char layer, further blocking heat and oxygen, while releasing low smoke and no toxic or harmful gases, ensuring the safety of personnel evacuation.

[0007] Preferably, in S6, online detection and closed-loop control: key parameters are detected in real time in S2, S3, S4 and S5: the thickness and surface roughness of the microparticle friction layer are measured using a white light interferometer or laser confocal instrument with a measurement accuracy of ±1μm; the friction coefficient is measured at 23℃, 90℃ and 200℃ using a winding friction tester to ensure that the friction performance meets the design requirements; the temperature of each curing process is monitored using an infrared thermometer to ensure the curing effect; based on the detection results, the coating flow rate and curing temperature and time are adjusted in a closed loop to keep the performance parameters of the finished cable core stable within the design window and improve the consistency of mass production.

[0008] Preferably, the pultrusion forming process specifically includes: By controlling the mold temperature and pultrusion speed, the glass transition temperature of the resin matrix is ​​made to reach above 200℃. The mold temperature is 180~220℃, the pultrusion speed is 1~3m / min, and the curing time is 10~30min. These temperature parameters ensure that no softening or deformation occurs under high-temperature conditions, guaranteeing stable load-bearing performance and achieving dimensional accuracy and performance consistency of carbon fiber microrods, ultimately resulting in carbon fiber microrods with smooth surfaces.

[0009] Preferably, in step S2, the plasma activation treatment has a power of 400W and a duration of 45s. This increases the surface energy of the microrod to at least 48mN / m, enhancing the adhesion of subsequent coatings.

[0010] Preferably, in S2, the elastic reset layer specifically comprises: After uniformly mixing the ceramicized powder of the whetstone with inorganic filler at a volume ratio of 13:7, an elastic resetting layer material is obtained. The elastic resetting layer material is coated on the surface of carbon fiber microrods at a coating flow rate of 5~20mL / min and cured at 180~220℃ for 10~30min to form an elastic resetting layer with a dry film thickness of 30~80μm. The Shore hardness is controlled at 60~75, and the loss factor tanδ is 0.15~0.25 at 23℃ and 10Hz. It can provide stable recovery force after unloading, effectively reduce residual elongation, and has low smoke and halogen-free environmental protection characteristics, and does not release toxic and harmful gases in the event of a fire.

[0011] Preferably, the inorganic filler is one or both of alumina and silicon dioxide.

[0012] Preferably, in S2, the microparticle friction layer specifically comprises: Polyamide-imide (PAI) and silica sol were mixed in a 1:1 mass ratio to form a binder. Microspheres with a liquid component of 30-45% were added and stirred evenly to obtain a coating solution. Carbon fiber microrods were immersed in the coating solution and then removed and cured at 200-240℃ for 15-40 min to obtain carbon fiber microrods with a dry film thickness of 10-80 μm and a surface roughness Ra of 3-8 μm.

[0013] Preferably, the microspheres are one or both of silicon dioxide and alumina, the median particle size D50 of the main particles of the microspheres is 6~10μm, and the microspheres are doped with 5~10% by volume of dopants with a particle size of 30~50μm.

[0014] Preferably, after forming the elastic resetting layer, the process also includes pressing spiral ribs, pressing spiral microgrooves on the surface of the carbon fiber microrod using a special mold, controlling the protrusion height to be 20~40μm and the surface coverage to be 40~70%, thereby optimizing the interface contact performance.

[0015] Preferably, in S3, the binding tension is 5~15N and the binding gap is 3~6%, which ensures good interface contact between adjacent microrods, while avoiding excessive gap affecting the uniformity of load bearing or excessive gap causing squeezing damage.

[0016] Preferably, in S4, the pitch of the stranding is no greater than 32mm to ensure the conductivity and flexibility of the conductor layer.

[0017] Preferably, in S5, the mica tape and the fiberglass tape adopt a laminated structure with a wrapping overlap rate of 20-30%.

[0018] Preferably, in S5, the extrusion temperature is 180~220℃, the extrusion speed is 1~5m / min, and the thickness of the insulating protective layer is 0.3~3.0mm.

[0019] Preferably, after forming the conductor layer, a filler layer containing phase change microcapsules is also provided. After stranding, the phase change microcapsules and filler material are mixed evenly and filled into the gaps between the conductor layers, and then a fireproof isolation layer is wrapped around them.

[0020] Preferably, the filler material in the filler layer is one or both of polypropylene (PP) and polyethylene (PE). The mass percentage of phase change microcapsules in the filler layer is 10-15%. The phase change microcapsules are one or more of polyethylene glycol (PEG), higher fatty alcohols, and polyol esters. The phase change temperature is controlled at 150-180℃ and the melting enthalpy at 120-180J / g. Under rated current carrying conditions, they can absorb hot spot heat, ensuring that the content of phase change microcapsules meets the hot spot suppression requirements. Through the bonding and supporting effect of the filler matrix, the structural integrity of the filler layer is guaranteed, avoiding problems such as decreased mechanical strength and easy cracking caused by excessive microcapsule content. Compared with the structure without phase change microcapsules, the hot spot peak temperature rise is reduced by not less than 10K, avoiding performance failure caused by local overheating.

[0021] Therefore, the present invention employs the above-mentioned fire-resistant carbon fiber composite cable core and its preparation method, and the beneficial effects are as follows: Strong resistance to fretting wear: This invention sets up an interface functional layer composed of an elastic reset layer and a micro-particle friction layer. The elastic reset layer can provide stable recovery force after unloading, so that the residual elongation of the wire core after being stretched to 40%~60% of the rated tension and held for 1 hour and then unloaded for 1 hour is no more than 0.10%. The micro-particle friction layer, through the gradation of main particles and secondary particles and the spiral micro-groove design, ensures that the coefficient of friction is stable in a wide temperature range (23~200℃), suppresses interlayer micro-slippage and fretting wear, and improves the anti-slip capability.

[0022] Outstanding fire resistance: This invention adopts a dual fireproof structure with a fireproof isolation layer and a low-smoke halogen-free insulation protective layer. The fireproof isolation layer can form a stable heat insulation barrier in a fire, and the insulation protective layer can expand into charcoal. The dual protection ensures that the wire core maintains the integrity of the circuit under high-temperature fire conditions. At the same time, the selection of low-smoke halogen-free materials ensures that the amount of smoke is low and there are no toxic or harmful gases during a fire, thus ensuring the safety of personnel evacuation.

[0023] Good production consistency: This invention monitors key parameters such as the thickness, roughness, and friction coefficient of the interface functional layer in real time through online detection and closed-loop control. By adjusting the coating flow rate, linear speed, and curing parameters, it ensures the stable performance of each batch of products.

[0024] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0025] Figure 1This is a graph showing the cyclic fretting wear results of an embodiment of the fire-resistant carbon fiber composite cable core and its preparation method according to the present invention. Detailed Implementation

[0026] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0027] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0028] Example 1 A fire-resistant carbon fiber composite cable core is provided. The composite load-bearing core is formed by 37 carbon fiber microrods bundled together in parallel. Each carbon fiber microrod has a diameter of 1.0 mm. From the inside out, each carbon fiber microrod has an elastic reset layer and a micro-particle friction layer, forming an interface functional layer. Centered on the composite load-bearing core, from the inside out, there are a conductor layer, a fireproof isolation layer, and an insulation protection layer.

[0029] The resin matrix is ​​epoxy resin with a glass transition temperature (Tg) of 220℃. The elastic reset layer is a continuous thin-sleeve structure of 13:7 volume ratio of zeolite ceramic powder and alumina filler, with a dry film thickness of 50μm, a Shore hardness (Type A) of 68, and a loss factor (tanδ) of 0.20 at 23℃ and 10Hz. The microparticle friction layer consists of a binder composed of polyamide-imide and silica sol (mass ratio 1:1) carrying 35% by volume of silica microspheres. The main particles have a D50 of 8μm, and 8% by volume of 40μm silica particles are incorporated. The dry film thickness is 40μm, the surface roughness is Ra=5μm, the static friction coefficient is 0.58 and the dynamic friction coefficient is 0.48 at 23℃, and the friction coefficient retention rate at 200℃ (based on the dynamic friction coefficient at 23℃) is 85%. The conductor layer has a cross-sectional area of ​​6mm² of stranded tin-plated copper wire. 2 The fireproof isolation layer is wrapped alternately, with three layers in total. The low-smoke halogen-free flame-retardant material of the insulating protective layer is a low-smoke halogen-free flame-retardant polyolefin with a thickness of 1.5 mm, containing 25% by volume of an expanded char flame-retardant system.

[0030] Its preparation method is as follows: S1. Preparation of carbon fiber microrods: Carbon fiber bundles are impregnated with epoxy resin matrix and pultruded through a die to obtain carbon fiber microrods with a diameter of 1.0 mm. The die temperature is 200℃, the pultrusion speed is 2m / min, and the curing time is 20min.

[0031] S2. Preparation of interface functional layer: Plasma activation treatment (power 400W, time 45s) is performed on the outer surface of carbon fiber microrods. The elastic reset layer is prepared by spraying (coating flow rate 10mL / min) and cured at 200℃ for 20min. The micro-particle friction layer is prepared by dip coating. The binder and silica particles are mixed evenly to form a coating liquid. After dip coating, it is cured at 220℃ for 25min.

[0032] S3. Bundling to form a composite load-bearing core: 37 carbon fiber microrods are bundled together in parallel using a bundling machine with a bundling tension of 10N and a bundling gap of 4%.

[0033] S4. Preparation of conductor layer: Composite load-bearing core and tin-plated copper wire are stranded together with a stranding pitch of 30mm.

[0034] S5. Preparation of fireproof isolation layer and insulation protection layer: Mica tape and fiberglass tape are wrapped to form fireproof isolation layer (overlap rate 25%), and insulation protection layer is extruded (extrusion temperature 200℃, extrusion speed 3m / min, thickness 2.0mm) to obtain cable core.

[0035] S6. Online detection and closed-loop control: The thickness and roughness of the micro-particle friction layer are measured by laser confocal measurement, the friction coefficient at various temperatures is measured by a winding friction tester, and the coating flow rate and linear speed are adjusted to ensure that the parameters meet the standards.

[0036] Tests showed that the cable cores of this embodiment maintained circuit integrity for 90 minutes under IEC 60331-21 test conditions, and the smoke transmittance during combustion was ≥60%, with no release of toxic or harmful gases.

[0037] Example 2 A fire-resistant carbon fiber composite cable core differs from Embodiment 1 in that the microparticle friction layer is provided with spiral microgrooves, with a protrusion height of 30μm, a pitch of 0.3mm, and a surface coverage of 55%. The static friction coefficient is 0.58 at 23℃, the dynamic friction coefficient is 0.51, and the friction coefficient retention rate at 200℃ (based on the dynamic friction coefficient at 23℃) is 92%.

[0038] Its preparation method is as follows: S1. Preparation of carbon fiber microrods: Carbon fiber bundles are impregnated with epoxy resin matrix and pultruded through a die to obtain carbon fiber microrods with a diameter of 1.0 mm. The die temperature is 200℃, the pultrusion speed is 2m / min, and the curing time is 20min.

[0039] S2. Preparation of interface functional layer: Plasma activation treatment (power 400W, time 45s) is performed on the outer surface of carbon fiber microrods. The elastic reset layer is prepared by spraying (coating flow rate 10mL / min) and cured at 200℃ for 20min. The micro-particle friction layer is prepared by dip coating. The binder and silica particles are mixed evenly to form a coating liquid. After dip coating, it is cured at 220℃ for 25min. The spiral microgroove is pressed by a special mold.

[0040] S3. Bundling to form a composite load-bearing core: 37 carbon fiber microrods are bundled together in parallel using a bundling machine with a bundling tension of 10N and a bundling gap of 4%.

[0041] S4. Preparation of conductor layer: Composite load-bearing core and tin-plated copper wire are stranded together with a stranding pitch of 30mm.

[0042] S5. Preparation of fireproof isolation layer and insulation protection layer: Mica tape and fiberglass tape are wrapped to form fireproof isolation layer (overlap rate 25%), and insulation protection layer is extruded (extrusion temperature 200℃, extrusion speed 3m / min, thickness 2.0mm) to obtain cable core.

[0043] S6. Online detection and closed-loop control: The thickness and roughness of the micro-particle friction layer are measured by laser confocal measurement, the friction coefficient at various temperatures is measured by a winding friction tester, and the coating flow rate and linear speed are adjusted to ensure that the parameters meet the standards.

[0044] Tests showed that the cable cores of this embodiment maintained circuit integrity for 90 minutes under IEC 60331-21 test conditions, and the smoke transmittance during combustion was ≥60%, with no release of toxic or harmful gases.

[0045] Example 3 A fire-resistant carbon fiber composite cable core differs from Example 2 in that: a filling layer is provided on the surface of the conductor layer, the filling material is polypropylene, and 12% phase change microcapsules are incorporated, the phase change microcapsules are polyethylene glycol, the phase change temperature is 160℃, and the melting enthalpy is 150J / g.

[0046] Its preparation method is as follows: S1. Preparation of carbon fiber microrods: Carbon fiber bundles are impregnated with epoxy resin matrix and pultruded through a die to obtain carbon fiber microrods with a diameter of 1.0 mm. The die temperature is 200℃, the pultrusion speed is 2m / min, and the curing time is 20min.

[0047] S2. Preparation of interface functional layer: Plasma activation treatment (power 400W, time 45s) is performed on the outer surface of carbon fiber microrods. The elastic reset layer is prepared by spraying (coating flow rate 10mL / min) and cured at 200℃ for 20min. The micro-particle friction layer is prepared by dip coating. The binder and silica particles are mixed evenly to form a coating liquid. After dip coating, it is cured at 220℃ for 25min. The spiral microgroove is pressed by a special mold.

[0048] S3. Bundling to form a composite load-bearing core: 37 carbon fiber microrods are bundled together in parallel using a bundling machine with a bundling tension of 10N and a bundling gap of 4%.

[0049] S4. Preparation of conductor layer: Composite load-bearing core and tin-plated copper wire are stranded together with a stranding pitch of 30mm.

[0050] S5. After stranding, the phase change microcapsules are mixed evenly with the filler material and filled into the gaps between the conductor layers, and then wrapped with a fireproof isolation layer.

[0051] S6. Preparation of fireproof isolation layer and insulation protection layer: Mica tape and fiberglass tape are wrapped to form fireproof isolation layer (overlap rate 25%), and insulation protection layer is extruded (extrusion temperature 200℃, extrusion speed 3m / min, thickness 2.0mm) to obtain cable core.

[0052] S7. Online detection and closed-loop control: The thickness and roughness of the micro-particle friction layer are measured by laser confocal measurement, the friction coefficient at various temperatures is measured by a winding friction tester, and the coating flow rate and linear speed are adjusted to ensure that the parameters meet the standards.

[0053] Tests showed that the cable cores of this embodiment maintained circuit integrity for 90 minutes under IEC 60331-21 test conditions, and the smoke transmittance during combustion was ≥60%, with no release of toxic or harmful gases.

[0054] Comparative Example 1 A fire-resistant carbon fiber composite cable core, specifically a commercially available ACCC carbon fiber composite core conductor.

[0055] Test 1. The fretting wear resistance and interfacial peel force of the cable cores prepared in Examples 1 and 2 were analyzed. The fretting wear results at 200℃ and 1000 cycles are as follows: Figure 1 As shown in Table 1, the test results are as follows.

[0056] Table 1 Test Indicators, Conditions, and Results

[0057] As shown in Table 1, the dynamic friction coefficients of Example 2 at 23℃, 90℃, and 200℃ reached 0.51 (6.25% higher than Example 1), 0.49, and 0.47, respectively. The friction coefficient retention rate at 200℃ reached 92% (8.2% higher than Example 1). The spiral microgrooves of Example 2, through physical meshing, made the interlayer contact pressure distribution more uniform, and could still maintain a stable friction state at high temperature (200℃). Compared with the smooth surface of Example 1, it further suppressed the interlayer micro-slippage, thus significantly improving the friction coefficient and having a better retention rate. The wear reduction was the largest, reflecting the effect of structural improvement on suppressing high-temperature fretting wear. The peeling force was increased by more than 30% at room temperature and by more than 50% at high temperature, further verifying the improvement in anti-slip capability.

[0058] Depend on Figure 1 It can be seen that, due to the physical meshing effect of the spiral microgrooves, the wear rate in Example 2 is slower during the initial wear period (0-200 cycles), demonstrating the rapid enhancement of interface stability by the structure. During the stable wear period (201-600 cycles), the wear rates of both Examples 1 and 2 tend to level off, and the overall wear amount of Example 2 is smaller, indicating that the spiral microgrooves disperse frictional stress. During the later wear period (601-1000 cycles), the wear rate further decreases, and the wear amount of Example 2 increases slowly, further verifying that Example 2 has superior interface wear resistance and durability.

[0059] 2. Hot spot peak temperature rise analysis was performed on the cable cores prepared in Examples 1 to 3 and the cable core of Comparative Example 1. The results of rated current carrying capacity of 150A and continuous 24h are shown in Table 2.

[0060] Table 2 Results of Peak Temperature Rise in Hotspots

[0061] As shown in Table 2, the phase change microcapsule filling layer of Example 3 can absorb the heat of hot spots, and the peak temperature rise of hot spots is reduced by 36K compared with Comparative Example 1. This avoids accelerated insulation aging caused by local overheating and significantly improves the long-term operational stability of the cable under rated current conditions.

[0062] Therefore, the present invention adopts the above-mentioned fireproof carbon fiber composite cable core and its preparation method to improve the electrical integrity and resistance to fretting wear of the cable core under high temperature and fire conditions, while improving the stability of mass production.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a fire-resistant carbon fiber composite cable core, characterized in that, Includes the following steps: S1. Preparation of carbon fiber microrods: Carbon fiber bundles are impregnated with a resin matrix and pultruded through a mold to obtain carbon fiber microrods with a diameter of 0.5~1.5mm; S2. Preparation of interface functional layer: Plasma treatment is performed on the surface of the carbon fiber microrod obtained in S1, and then an elastic reset layer and a micro-particle friction layer are sequentially coated on the surface of the carbon fiber microrod to obtain the carbon fiber microrod with interface functional layer. S3. Bundling to form a composite load-bearing core: The carbon fiber microrods obtained in S2 are bundled together in parallel in groups of 19 to 61 using a bundling machine to obtain a composite load-bearing core; S4. Preparation of conductor layer: The composite load-bearing core obtained in S3 and the tin-plated copper wire are twisted together to form a conductor layer; S5. Preparation of fireproof isolation layer and insulation protection layer: Mica tape and fiberglass tape are used to wrap and form fireproof isolation layer. Then, low smoke halogen-free flame retardant material is heated and melted and extruded on the outside of fireproof isolation layer to form insulation protection layer, thus obtaining fireproof carbon fiber composite cable core.

2. The method for preparing a fire-resistant carbon fiber composite cable core according to claim 1, characterized in that, In S1, the pultrusion forming process specifically includes: The glass transition temperature of the resin matrix is ​​made to reach above 200℃ by controlling the mold temperature and pultrusion speed. The mold temperature is 180~220℃, the pultrusion speed is 1~3m / min, and the curing time is 10~30min.

3. The method for preparing a fire-resistant carbon fiber composite cable core according to claim 1, characterized in that, In S2, the plasma activation treatment has a power of 400W and a time of 45s.

4. The method for preparing a fire-resistant carbon fiber composite cable core according to claim 1, characterized in that, In S2, the elastic reset layer specifically comprises: After uniformly mixing the zeolite powder with inorganic filler at a volume ratio of 13:7, an elastic resetting layer material is obtained. The elastic resetting layer material is coated on the surface of carbon fiber microrods at a coating flow rate of 5~20mL / min and cured at 180~220℃ for 10~30min to form an elastic resetting layer with a dry film thickness of 30~80μm.

5. The method for preparing a fire-resistant carbon fiber composite cable core according to claim 1, characterized in that, In S2, the microparticle friction layer specifically comprises: Polyamide-imide and silica sol were mixed in a mass ratio of 1:1 to form a binder. Microspheres with a liquid component of 30-45% were added and stirred evenly to obtain a coating solution. Carbon fiber microrods were immersed in the coating solution and then removed and cured at 200-240℃ for 15-40 min to obtain carbon fiber microrods with a dry film thickness of 10-80 μm and a surface roughness Ra of 3-8 μm.

6. The method for preparing a fire-resistant carbon fiber composite cable core according to claim 1, characterized in that, In S2, after the elastic resetting layer is formed, the process also includes pressing spiral ribs. Spiral microgrooves are pressed on the surface of carbon fiber microrods using a special mold, controlling the protrusion height to be 20~40μm and the surface coverage to be 40~70%.

7. The method for preparing a fire-resistant carbon fiber composite cable core according to claim 1, characterized in that, In S3, the binding tension is 5~15N and the binding gap is 3~6%.

8. The method for preparing a fire-resistant carbon fiber composite cable core according to claim 1, characterized in that, In S5, the mica tape and the fiberglass tape adopt a laminated structure with a wrapping overlap rate of 20-30%.

9. The method for preparing a fire-resistant carbon fiber composite cable core according to claim 1, characterized in that, After the conductor layer is formed, a filler layer containing phase change microcapsules is also included. After stranding, the phase change microcapsules and filler material are mixed evenly and filled into the gaps between the conductor layers, and then a fireproof isolation layer is wrapped around them.

10. A fire-resistant carbon fiber composite cable core prepared by a method for preparing a fire-resistant carbon fiber composite cable core as described in any one of claims 1 to 9.

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