A novel high-temperature-resistant fiber braided coaxial cable and a preparation process thereof

Abstract

The present application relates to coaxial cable preparation technical field, especially to a kind of novel high-temperature-resistant fiber braided coaxial cable and its preparation process, including basalt fiber filament as core yarn, it is wrapped polyimide fiber to form elastic intermediate layer on its outer periphery, ceramic silicone rubber fiber and high-temperature-resistant aramid fiber are collectively wrapped to form composite braided silk on the outer periphery of elastic intermediate layer;Composite braided silk is subjected to coupling agent impregnation and drying treatment to form crosslinked interface film on its surface;In the shielding layer of semi-finished product, the composite braided silk after processing is woven;In the downstream of weaving point, the semi-finished product after weaving is heat set treatment, to form dense closed film on the surface of braided layer;According to preset length, after braided layer is cooled, self-locking mesh tube structure with continuous inwardly holding force is formed on shielding layer, to obtain high-temperature-resistant fiber braided coaxial cable.The present application improves the reliability of novel high-temperature-resistant fiber braided coaxial cable.

Description

Technical Field

[0001] This invention relates to the field of coaxial cable manufacturing technology, and in particular to a novel high-temperature resistant fiber braided coaxial cable and its manufacturing process. Background Technology

[0002] In industrial environments such as aerospace, oil drilling, metallurgy, and rail transportation, coaxial cables used for radio frequency signal and power transmission often need to operate reliably for extended periods under combined conditions of extreme high temperatures above 300°C, instantaneous impact from open flames, high humidity, and strong mechanical vibration. The cable sheath, as the primary barrier against external environmental damage and maintaining the integrity of the internal structure, directly determines the cable's service life and system safety. Fiber-braided sheaths face a dilemma: achieving high temperature resistance, high flexibility, and effective protection simultaneously is difficult. Sheaths made from pure inorganic fibers, such as basalt fiber and glass fiber, while offering high temperature resistance, suffer from inherent fiber brittleness. When cables are repeatedly bent, they are prone to pulverization due to fiber breakage and fretting wear, resulting in a loose braided structure and loss of mechanical protection. More importantly, the high surface energy and large pores between yarns of the pure inorganic fiber braided layer cannot effectively block the penetration of liquid water and corrosive media, often requiring an additional sealing layer, sacrificing the advantages of the braided structure. Furthermore, there is a structural stability problem caused by a severe mismatch in the coefficient of thermal expansion between the sheath and the internal metal shielding layer. Under drastic temperature cycles, the braided sheath is prone to delamination and slippage with the shielding layer, forming gaps. This not only exacerbates the intrusion of moisture but also causes the mechanical protection function of the sheath to completely fail.

[0003] Chinese Patent Application Publication No. CN119181529A discloses a highly elastic flexible cable and its preparation method, comprising n conductive wires, a braided sleeve sleeved on the outside of the conductive wires, a functional layer coaxially disposed on the outside of the braided sleeve, and a wear-resistant layer coaxially disposed on the outside of the functional layer. It also includes multiple central pillars arranged in an array inside the n conductive wires. The end faces of two adjacent central pillars arranged coaxially are fixedly connected by multiple circumferentially distributed connecting strips. The other end of each central pillar is fixedly connected to one end face of a chuck. The end face of the chuck has n through holes arranged in a circumferential array. The same insulating sleeve segment between two adjacent chucks is spirally arranged on the central pillar, with m spiral turns, and 1 / n ≤ m ≤ 1. The same insulating sleeve at both ends of the chuck is arranged in a reverse spiral direction.

[0004] However, existing technology does not take into account the poor structural stability of the braided sheath when the cable is subjected to complex working conditions of both harsh environment and mechanical stress, and thus cannot provide long-term reliable protection for the internal structure of the coaxial cable. Summary of the Invention

[0005] Therefore, the present invention provides a novel high-temperature resistant fiber braided coaxial cable and its manufacturing process to overcome the problem in the prior art that the braided sheath has poor structural stability under complex working conditions where the cable is subjected to both harsh environment and mechanical stress, thus failing to provide long-term reliable protection for the internal structure of the coaxial cable.

[0006] To achieve the above objectives, the present invention provides a novel manufacturing process for a high-temperature resistant fiber braided coaxial cable, comprising: Using basalt fiber filaments as the core yarn, polyimide fibers are wrapped around the outer periphery to form an elastic intermediate layer. Ceramicized silicone rubber fibers and high-temperature resistant aramid fibers are mixed to form a composite braided yarn to wrap around the outer periphery of the elastic intermediate layer. The composite braided yarn is impregnated with a coupling agent and dried to form a cross-linked interface film on the surface of the composite braided yarn; Semi-finished products are prepared based on an inner conductor, a high-temperature resistant insulating layer, and a shielding layer; The treated composite braided yarn is used to braid the shielding layer of the semi-finished product. During the braiding process, the tension of several spindles of the braiding machine is controlled by dividing and grading the spindles, so that the spindles in the winding area and the spindles in the filling area are differentiated by the unwinding tension, so as to form an internal stress distribution in the braided layer. Downstream of the weaving point, the semi-finished product after weaving is heat-set. After the thermoplastic fiber components at the weaving intersection undergo surface micro-melting and heat-melting and bonding with each other, a tight sealing film is formed on the surface of the weaving layer. After the braided layer is cooled for a preset time, a self-locking mesh cylinder structure with a continuous inward clamping force is formed on the shielding layer to obtain a high-temperature resistant fiber braided coaxial cable.

[0007] Furthermore, the process for preparing the composite braided yarn includes: The polyimide fiber is wrapped around the surface of the core yarn with a twist of 40 to 60 twists / 10cm to obtain the elastic intermediate layer; After mixing the ceramicized silicone rubber fiber and the high-temperature resistant aramid fiber, the composite braided yarn is obtained by wrapping it in a mesh shape in the elastic intermediate layer with a twist of 20-30 twists / 10cm.

[0008] Furthermore, the process of impregnating with the coupling agent includes: A complex coupling agent containing perfluorooctyltriethoxysilane and KH-560 silane coupling agent in a mass ratio of 1:2 was selected, and nano-silica sol accounting for 5% of the total mass of the complex coupling agent was added as a film-forming aid.

[0009] Furthermore, the drying process includes: During the impregnation of the coupling agent, the vacuum is drawn to -0.08 MPa and maintained for 15 to 30 minutes to allow the coupling agent solution to fully penetrate and displace the air in the fiber bundle. After low-temperature drying at 60–80°C, the temperature is raised to 280–320°C and maintained for 5–10 minutes to allow the coupling agent to undergo a cross-linking reaction and bond to the fiber surface.

[0010] Furthermore, the process of preparing the semi-finished product includes: Between the high-temperature resistant insulation layer and the shielding layer, a polyimide film with a temperature resistance greater than or equal to 350°C is wrapped as a physical buffer layer. The outer surface of the shielding layer is coated with polyimide varnish and cured to form a thermally insulating interface.

[0011] Furthermore, the weaving process includes: The braiding machine has an even number of spindles, and the number of spindles in the winding zone is equal to the number of spindles in the filling zone; The unwinding tension of the spindle in the winding zone of the braiding machine is adjusted to 1.3 to 1.8 N, and the unwinding tension of the spindle in the filling zone is adjusted to 0.8 to 1.2 N, thereby creating a tension difference between the winding zone and the filling zone to form an internal stress distribution in the braided structure.

[0012] Furthermore, the heat setting process includes: The woven semi-finished product is fed into an induction heating tunnel and heated at 350-380°C for 3-5 seconds.

[0013] Furthermore, the heat setting process also includes: The woven semi-finished product is passed through a tempering tunnel at 260-300°C for 15-30 seconds, and then the outer surface of the woven semi-finished product is rapidly cooled by a room temperature airflow to form a tightly sealed film on the surface of the woven layer.

[0014] Furthermore, the process of determining whether a self-locking mesh cylinder structure has been formed includes: The initial outer diameter of the braided layer before cooling and the shrinkage outer diameter after cooling were collected to calculate the radial shrinkage rate. When the radial shrinkage rate is in the range of 0.5% to 2%, it is determined that the self-locking mesh cylinder structure has been formed.

[0015] This invention also provides a novel high-temperature resistant fiber-braided coaxial cable, wherein the raw materials for preparing the composite braided yarn are, by mass parts: The basalt fiber is 40-60 parts, the polyimide fiber is 20-40 parts, the ceramicized silicone rubber fiber is 10-30 parts, and the high-temperature resistant aramid fiber is 5-10 parts. The ceramicized silicone rubber fiber has an initial ceramicization temperature greater than 380°C and is completely transformed into a hard ceramic shell above 450°C.

[0016] Compared with the prior art, the beneficial effects of the present invention are that by implementing differentiated tension control on the main winding spindle and the filling spindle during the weaving process, an asymmetric internal stress distribution is constructed inside the weaving layer; subsequently, controlled heat setting treatment is performed downstream of the weaving point, and the surface micro-melting and hot-melting bonding of the thermoplastic fiber components are used to form a permanent connection at the weaving intersection. After cooling, continuous radial shrinkage stress is generated, thereby forming a self-locking mesh cylinder structure with a continuous inward clamping force on the internal shielding layer. The self-locking mesh cylinder structure does not require external adhesives and can maintain a tight fit between the woven sheath and the shielding layer for a long time under temperature cycling and mechanical bending conditions, effectively avoiding delamination, bulging and slippage failure caused by differences in thermal expansion coefficients.

[0017] Furthermore, this invention employs a composite braiding structure design, using high-modulus, high-temperature resistant basalt fiber filaments as the load-bearing skeleton, wrapping them with polyimide fibers to form an elastic intermediate layer, and then twisting and binding ceramicized silicone rubber fibers and high-temperature resistant aramid fibers into the outer layer. This confines the brittle inorganic fibers to the yarn core, protecting them from direct damage by braiding friction and bending stress, while the tough organic fibers in the outer layer bear the surface wear and deformation. Thus, under long-term working conditions at 300°C, this invention simultaneously achieves a combination of high-strength load-bearing capacity and resistance to repeated bending fatigue, solving the defects of high brittleness and easy pulverization of inorganic fiber braided layers.

[0018] Furthermore, this invention involves vacuum-assisted impregnation and step-curing of the composite braided yarns before weaving, followed by low-temperature drying to remove the solvent and then high-temperature rapid curing. This process allows the composite coupling agent system containing fluorinated silanes and epoxy silanes to form a dense cross-linked interface film on the surface of each fiber component. The cross-linked interface film firmly bonds the hydrophilic inorganic fibers and the hydrophobic organic fibers into a whole, reducing the interfacial gaps between fibers. At the same time, it imparts overall hydrophobic properties to the braided sheath, enabling the high-density porous braided structure to prevent liquid water penetration without a solid sealing layer, thereby achieving the structural waterproof and dustproof effect of the flexible braided sheath.

[0019] Furthermore, by precisely limiting the initial ceramization temperature of the ceramicized silicone rubber fibers to be no lower than the upper limit of the heat setting temperature, this invention ensures that the controlled heating during the heat setting process only triggers the surface micro-melting adhesion of thermoplastic components such as polyimide, without stimulating the ceramization transformation of the ceramicized silicone rubber fibers. Under normal long-term working conditions at 300°C, the woven sheath maintains its structural integrity by relying on the thermal stability of the basalt fibers and polyimide fibers. When exposed to flames or instantaneous ultra-high temperature impacts, the ceramicized silicone rubber fibers distributed on the outer layer of the woven sheath rapidly transform into a hard ceramic shell above 450°C, forming a physical barrier with the basalt fibers to isolate oxygen and radiant heat. This achieves a graded response of maintaining flexibility under normal working conditions and actively forming a fireproof and heat-insulating layer under disaster conditions. Attached Figure Description

[0020] Figure 1 This is a flowchart illustrating the manufacturing process of the novel high-temperature resistant fiber braided coaxial cable according to an embodiment of the present invention. Figure 2 This is a flowchart illustrating the coupling agent impregnation and drying process of composite braided yarns according to an embodiment of the present invention; Figure 3 This is a flowchart of the weaving process according to an embodiment of the present invention; Figure 4 This is a logic diagram for determining whether a self-locking mesh cylinder structure has been formed, according to an embodiment of the present invention. Detailed Implementation

[0021] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0022] Please see Figures 1 to 3 As shown, Figure 1 This is a flowchart illustrating the manufacturing process of the novel high-temperature resistant fiber braided coaxial cable according to an embodiment of the present invention. Figure 2 This is a flowchart illustrating the coupling agent impregnation and drying process of composite braided yarns according to an embodiment of the present invention. Figure 3 This is a flowchart of the braiding process in an embodiment of the present invention. The manufacturing process of the novel high-temperature resistant fiber braided coaxial cable in this embodiment includes: Step S1: Using basalt fiber filament as the core yarn, wrap polyimide fiber around its outer periphery to form an elastic intermediate layer, and mix ceramicized silicone rubber fiber with high-temperature resistant aramid fiber to form a composite braided yarn to wrap around the outer periphery of the elastic intermediate layer. Step S11: Wrap polyimide fibers around the core yarn surface with a twist of 40-60 twists / 10cm to obtain an elastic intermediate layer; Step S12: After mixing ceramicized silicone rubber fibers and high-temperature resistant aramid fibers, the mixture is wrapped in an elastic intermediate layer with a twist of 20-30 twists / 10cm to obtain composite braided yarn.

[0023] Step S2: The composite braided yarn is impregnated with a coupling agent and dried to form a cross-linked interface film on the surface of the composite braided yarn. Step S21: Select a complex coupling agent containing perfluorooctyltriethoxysilane and KH-560 silane coupling agent in a mass ratio of 1:2, and add nano silica sol accounting for 5% of the total mass of the complex coupling agent as a film-forming aid.

[0024] It should be noted that the complex coupling agent is dispersed in an alcohol-water mixed solvent prepared by mixing ethanol and deionized water at a volume ratio of 8:2 to 9:1, so that the total mass concentration of the complex coupling agent is 2 to 5 wt%. During preparation, KH-560 is first added to a portion of the alcohol-water solvent, and the pH is adjusted to 3.5 to 4.5 with acetic acid. The mixture is then stirred at room temperature for 10 to 20 minutes for pre-hydrolysis. Separately, perfluorooctyltriethoxysilane is added to another portion of the alcohol-water solvent and stirred at room temperature for pre-hydrolysis for 10 to 20 minutes. The two pre-hydrolyzed solutions are then mixed, and nano-silica sol with a solid content of 20 to 30 wt% and an average particle size of 10 to 30 nm is added. After stirring and dispersing evenly, the coupling agent impregnation solution is obtained.

[0025] Step S22: During the impregnation of the coupling agent, the coupling agent solution is fully penetrated and the air inside the fiber bundle is replaced by drawing a vacuum to -0.08 MPa and maintaining it for 15 to 30 minutes. Step S23: After low-temperature drying at 60-80°C, the temperature is raised to 280-320°C and maintained for 5-10 minutes to allow the coupling agent to undergo a cross-linking reaction and bond to the fiber surface.

[0026] Step S3: Prepare a semi-finished product based on the inner conductor, high-temperature resistant insulation layer, and shielding layer; Step S31: Wrap a polyimide film with a temperature resistance greater than or equal to 350°C between the high-temperature resistant insulation layer and the shielding layer as a physical buffer layer. Step S32: Dip and coat the outer surface of the shielding layer with polyimide varnish and cure it to form a thermally insulating interface.

[0027] Step S4: The treated composite braided yarn is used to braid the shielding layer of the semi-finished product. During the braiding process, the tension of several spindles of the braiding machine is controlled by dividing and grading the spindles, so that the spindles in the winding area and the spindles in the filling area are differentiated in terms of the unwinding tension, so as to form an internal stress distribution in the braided layer. Step S41: Select a 16-spindle braiding machine; Step S42: On the 16-spindle braiding machine, the unwinding tension of the 8 winding spindles is adjusted so that the output tension reaches 1.3 to 1.8 N; Step S43: Adjust the unwinding tension of the other 8 filler spindles so that their output tension reaches 0.8 to 1.2 N, thereby creating a tension difference between the winding area and the filler area to form an internal stress distribution in the braided structure; Step S5: Downstream of the weaving point, the semi-finished product after weaving is heat-set. After the thermoplastic fiber components at the weaving intersection undergo surface micro-melting and heat-melting adhesion to each other, a tight sealing film is formed on the surface of the weaving layer. Step S51: The woven semi-finished product is fed into the induction heating tunnel. The induction heating tunnel includes a ring-shaped induction coil and a metal heating sleeve disposed inside the coil. The metal heating sleeve is made of a heat-resistant metal material, such as heat-resistant stainless steel or nickel-based alloy, and the inner diameter of the sleeve is slightly larger than the outer diameter of the cable. During operation, a medium-frequency or high-frequency alternating current is passed through the induction coil, and the alternating magnetic field generates eddy currents in the wall of the metal heating sleeve, causing the sleeve itself to rapidly heat up to 350-380°C. When the woven semi-finished product passes through the inside of the sleeve, the sleeve transfers heat to the non-metallic braided layer on the outer surface of the semi-finished product through thermal radiation and convection / conduction of the gap air, causing the thermoplastic fiber components at the braiding intersections to undergo surface micro-melting and thermally bond together; the heating time is 3-5 seconds. It should be noted that, since the braided layer is composed of non-conductive or weakly conductive fibers such as basalt fiber, polyimide fiber, ceramicized silicone rubber fiber and aramid fiber, it is impossible to directly generate sufficient eddy current heating effect in the induced electromagnetic field. Therefore, this embodiment adopts the above-mentioned indirect induction heating method, that is, using a metal heating sleeve as an electromagnetic energy-heat energy conversion element to transfer the heat generated by induction to the non-metallic braided layer, so as to achieve rapid and uniform surface micro-melting and heat setting.

[0028] In step S52, the braided layer semi-finished product after heat setting in step S51 is sent into a tempering tunnel, which is either a hot air tunnel or an infrared radiation tunnel. The temperature inside the tunnel is maintained at 260–300°C, and the braided layer semi-finished product passes through the tunnel for 15–30 seconds to release and homogenize the thermal stress inside the braided layer. Subsequently, the outer surface of the braided layer semi-finished product is rapidly cooled with a room temperature airflow. The temperature gradient is used to further densify the surface film of the braided layer, ultimately forming a tightly sealed film on the surface of the braided layer.

[0029] Step S6: After cooling the braided layer for a preset time, a self-locking mesh cylinder structure with a continuous inward clamping force is formed on the shielding layer to obtain a high-temperature resistant fiber braided coaxial cable.

[0030] Please see Figure 4As shown, this is a logic diagram for determining whether a self-locking mesh cylinder structure is formed according to an embodiment of the present invention. The process for determining whether a self-locking mesh cylinder structure is formed includes: The initial outer diameter of the braided layer before cooling and the shrinkage outer diameter after cooling were collected to calculate the radial shrinkage rate. When the radial shrinkage rate is less than 0.5%, it indicates that the hot melt bonding is insufficient and the clamping force is insufficient; when the radial shrinkage rate is higher than 2%, it indicates that the shrinkage is excessive, which will lead to excessive internal stress in the sheath or deformation of the shielding layer under pressure. Therefore, when the radial shrinkage rate is in the range of 0.5% to 2%, it is determined that the self-locking mesh cylinder structure has been formed. When the radial shrinkage rate is less than 0.5% or greater than 2%, it is determined that the self-locking mesh cylinder structure has not been formed.

[0031] Specifically, the radial shrinkage rate is calculated by subtracting the shrinkage outer diameter after cooling from the initial outer diameter before cooling, and then comparing it with the initial outer diameter before cooling. Specifically, a non-contact laser diameter gauge is used to continuously collect outer diameter data at the weaving point and the end of the cooling section. The collection frequency is no less than once per second, and the arithmetic mean of 10 consecutive measurements is taken as the initial outer diameter before cooling and the shrinkage outer diameter after cooling, respectively, to eliminate the influence of vibration and local non-uniformity.

[0032] In this embodiment, the preset duration is calculated based on the melting temperature of the thermoplastic fiber component that plays a role in hot-melt bonding, combined with the cable's outer diameter and braid thickness, to determine the time required to cool from the heat-setting temperature of 350-380°C to below the melting temperature. Specifically, an infrared thermometer is used to monitor the surface temperature of the braid layer online. When the temperature drops below the melting temperature of the thermoplastic fiber component, and further cooling continues until the component completes melt solidification and undergoes volume shrinkage, the hot-melt bonding area has completed solidification and generated shrinkage stress. At this point, the cooling endpoint is determined, and this period is defined as the preset duration. For cables with an outer diameter of 3-5 mm, under normal temperature air natural convection cooling conditions, the preset duration is typically 10-30 seconds.

[0033] It should be noted that cable segments that have been wound up and failed the inspection should be marked and isolated. The cable segment can be reheated offline using a heat setting device for a supplementary heat fusion treatment. The treatment temperature is 10-20°C lower than the initial setting temperature, and the time is shortened to 50%-70% of the initial treatment time. After cooling again, the radial shrinkage rate is tested. Only those that pass the test can be incorporated into the qualified products.

[0034] In this embodiment, the inner conductor, high-temperature resistant insulation layer, and shielding layer can all adopt conventional high-temperature resistant coaxial cable materials and structures in the art. For example, the inner conductor can be silver-plated copper single wire or stranded conductor; the high-temperature resistant insulation layer can be modified polytetrafluoroethylene, mica tape, or other insulating materials; and the shielding layer can be silver-plated copper wire braided shielding. The preparation of the semi-finished product can be carried out according to conventional processes known in the art, such as conductor stranding, insulation extrusion or wrapping, and shielding braiding.

[0035] Preferably, a high-temperature resistant polyimide film can be wrapped between the high-temperature resistant insulation layer and the shielding layer as a physical buffer layer; a layer of polyimide varnish can be dipped and cured on the outer surface of the shielding layer to improve the interfacial compatibility and thermal insulation effect between the shielding layer and the subsequent fiber braided sheath layer.

[0036] This embodiment also provides the raw materials for a novel high-temperature resistant fiber-braided coaxial cable, which, by weight parts, are: The composition is 40-60 parts basalt fiber, 20-40 parts polyimide fiber, 10-30 parts ceramicized silicone rubber fiber, and 5-10 parts high-temperature resistant aramid fiber. Among them, the initial ceramization temperature of the ceramicized silicone rubber fiber is greater than 380℃, and it is completely transformed into a hard ceramic shell above 450℃.

[0037] It should be noted that in this embodiment, the monofilament diameter of the basalt fiber filament is 9-13 μm; the fiber length of the polyimide short fiber is 30-60 mm and the linear density is 1.5-2.5 dtex; the monofilament diameter of the ceramicized silicone rubber fiber filament is 10-15 μm; and the linear density of the high-temperature resistant aramid filament is 20-40 tex.

[0038] Example 1: Ingredient quantities: 50 parts of 10μm basalt fiber, 30 parts of 45mm polyimide fiber, 15 parts of 13μm ceramicized silicone rubber fiber, and 5 parts of 30tex high-temperature resistant aramid fiber.

[0039] Preparation process: In step S11, polyimide fibers are wrapped around the core yarn with a twist of 50 twists / 10cm; in step S12, ceramicized silicone rubber fiber filaments and high-temperature resistant aramid fiber filaments are twisted together and then wrapped in a mesh in the elastic intermediate layer with a twist of 25 twists / 10cm. In step S22, vacuum impregnation is performed for 20 minutes; In step S23, the product is dried at 70°C and cured at 300°C for 8 minutes. In step S31, a polyimide film is wrapped around the surface; In step S32, polyimide varnish is applied and cured at 200°C.

[0040] In step S42, the winding spindle tension is 1.5N; In step S43, the filling spindle tension is 1.0 N; In step S51, the heat setting temperature is 370℃ and the time is 4 seconds; Step S52: Tempering temperature 280℃, time 20 seconds; The polyimide film has a thickness of 0.03 mm, and the polyimide varnish has a solid content of 20 wt%, prepared using polyamic acid as a solute and NMP as a solvent.

[0041] Example 2: Ingredient quantities: 60 parts of 13μm basalt fiber, 20 parts of 60mm polyimide fiber, 10 parts of 15μm ceramicized silicone rubber fiber, and 10 parts of 40tex high-temperature resistant aramid fiber.

[0042] Preparation process: Same as in Example 1.

[0043] Example 3: Ingredient quantities: 40 parts of 9μm basalt fiber, 40 parts of 30mm polyimide fiber, 15 parts of 10μm ceramicized silicone rubber fiber, and 5 parts of 20tex high-temperature resistant aramid fiber.

[0044] Preparation process: Same as in Example 1.

[0045] Example 4: Raw material proportions: Same as in Example 1.

[0046] Preparation process: Step S42 winding spindle tension 1.8N, Step S43 filling spindle tension 1.2N; the rest is the same as in Example 1.

[0047] Example 5: Raw material proportions: Same as in Example 1.

[0048] Preparation process: Step S51 heat setting temperature 350℃, time 5 seconds; the rest is the same as in Example 1.

[0049] Example 6: Raw material proportions: Same as in Example 1.

[0050] Preparation process: Step S52 tempering temperature 260℃, time 30 seconds; the rest is the same as in Example 1.

[0051] Example 7: Raw material proportions: Same as in Example 1.

[0052] Preparation process: Step S11 twist 40 twists / 10cm, Step S12 twist 20 twists / 10cm; other parameters are the same as in Example 1.

[0053] Example 8: Raw material proportions: Same as in Example 1.

[0054] Preparation process: Step S23 curing temperature 320℃, time 5 minutes; other parameters are the same as in Example 1.

[0055] Comparative Example 1: The difference from Example 1 is as follows: 70 parts basalt fiber, 10 parts polyimide fiber, 10 parts ceramicized silicone rubber fiber, and 10 parts high-temperature resistant aramid fiber. All other preparation parameters remain the same.

[0056] Comparative Example 2: The difference from Example 2 is that the ceramicized silicone rubber fiber is replaced with an equal amount of basalt fiber, i.e., 70 parts basalt fiber, 20 parts polyimide, and 10 parts high-temperature resistant aramid fiber. All other preparation parameters are the same.

[0057] Comparative Example 3: The difference from Example 3 is that the polyimide fiber was increased to 50 parts and the basalt fiber was reduced to 30 parts. The remaining components and preparation parameters are the same.

[0058] Comparative Example 4: The difference from Example 4 is that the tension of the wound spindle is 2.5N, and the tension of the filled spindle is 0.5N. The remaining components and preparation parameters are the same.

[0059] Comparative Example 5: The difference from Example 5 is: the heat setting temperature is 320°C, and the time is 5 seconds. Everything else is the same.

[0060] Comparative Example 6: The difference from Example 6 is that the tempering and quenching with ambient airflow in step S52 are omitted. The remaining components and preparation parameters are the same.

[0061] Comparative Example 7: The difference from Example 7 is that the twist in step S11 is 30 twists / 10cm, and the twist in step S12 is 15 twists / 10cm. The remaining components and preparation parameters are the same.

[0062] Comparative Example 8: The difference from Example 8 is that in step S23, the curing temperature is 350°C and the time is 10 minutes. The remaining components and preparation parameters are the same.

[0063] Testing and evaluation methods: To comprehensively evaluate the performance of coaxial cables, the following test methods were used: Long-term heat resistance aging: According to IEC 60216, the cable sample was placed in a 300℃ hot air circulating aging chamber for 1000 hours of continuous exposure. After being taken out, the sample was visually inspected at room temperature to observe for any abnormalities such as deformation, delamination, and cracking. Bending performance after aging: The cable aged at 300℃ / 1000h is bent 500 times in both directions with a bending radius ≤ 5 times the outer diameter of the cable, and the sheath is checked for breakage or delamination. Transmission loss: Measured according to IEC 61196-1 using a vector network analyzer at a test frequency of 10 GHz and a test temperature of 300 °C, unit dB / m; Flame retardant performance: The finished cable sheath layer samples were tested according to the vertical burning test of UL94 standard; Waterproof performance: The waterproof rating of the cable samples was tested according to IEC 60529. For cables expected to achieve IP67, an IPX7 test was conducted, in which a 1m long cable section was immersed in water at 25°C and a depth of 1m for 30 minutes. After removal, the sheath was peeled off, and the internal shielding and insulation layers were visually inspected for water leakage. For comparative samples that failed the IPX7 test, further water spray tests were conducted according to IPX5 (nozzle inner diameter 6.3mm, water flow rate 12.5L / min, distance 2.5-3m, continuous for at least 3 minutes) and IPX6 (nozzle inner diameter 12.5mm, water flow rate 100L / min, distance 2.5-3m, continuous for at least 3 minutes) to determine their actual protection level.

[0064] Please see Table 1 below for specific data.

[0065] Table 1 Summary of Performance Test Results Example 1 No aging, deformation, or delamination Bending radius less than 5 times the cable outer diameter, no breakage or delamination after 500 bends. 0.82dB / m V-0 IP67 Example 2 No aging, deformation, or delamination. Bending radius less than 5 times the cable outer diameter, no breakage or delamination after 500 bends. 0.84dB / m V-0 IP67 Example 3 No aging, deformation, or delamination. Bending radius less than 5 times the cable outer diameter, no breakage or delamination after 500 bends. 0.80dB / m V-0 IP67 Example 4 No aging, deformation, or delamination Bending radius less than 5 times the cable outer diameter, no breakage or delamination after 500 bends. 0.82dB / m V-0 IP67 Example 5 No aging, deformation, or delamination Bending radius less than 5 times the cable outer diameter, no breakage or delamination after 500 bends. 0.82dB / m V-0 IP67 Example 6 No aging, deformation, or delamination Bending radius less than 5 times the cable outer diameter, no breakage or delamination after 500 bends. 0.82dB / m V-0 IP67 Example 7 No aging, deformation, or delamination Bending radius less than 5 times the cable outer diameter, no breakage or delamination after 500 bends. 0.82dB / m V-0 IP67 Example 8 No aging, deformation, or delamination Bending radius less than 5 times the cable outer diameter, no breakage or delamination after 500 bends. 0.82dB / m V-0 IP67 Comparative Example 1 Surface microcracks A bending radius of less than 5 times the cable's outer diameter will cause cracks to form after 120 bending cycles. 0.95dB / m V-1 IPX5 Comparative Example 2 Hardening of sheath No delamination after 500 cycles, but poor flame retardancy. 0.85dB / m V-1 IPX6 Comparative Example 3 relaxation, delamination Delamination occurs after bending 500 times. 0.83dB / m V-0 IPX5 Comparative Example 4 Local deformation Bending the sheath 300 times causes wrinkles 0.82dB / m V-0 IPX5 Comparative Example 5 Early separation Separate after bending 100 times 0.90dB / m V-0 IPX5 Comparative Example 6 Surface microcracks No delamination after 500 bends, but surface microcracks were observed. 0.83dB / m V-0 IPX6 Comparative Example 7 Surface roughness 300 bends to raise nap 0.82dB / m V-0 IPX5 Comparative Example 8 Microdelamination appeared after 500 hours. No delamination after 500 bends, but delamination after high temperature. 0.88dB / m V-0 IP67 In Example 1, all raw material ratios and preparation parameters were within the median of the preferred range. The synergistic effect of each component was ideal. Basalt provided skeletal strength, polyimide provided elastic cushioning and hot-melt bonding matrix, ceramicized silicone rubber provided fire resistance, aramid fiber enhanced wear resistance, heat setting ensured full hot-melt bonding at the weaving intersections, and the self-locking radial shrinkage rate after cooling was 1.2%, which was in the middle of the acceptable range. All properties reached the optimal level.

[0066] In Example 2, increasing the basalt content to 60 parts further enhanced the tensile strength and high-temperature dimensional stability of the cable, slightly increased the dielectric constant, and slightly increased the transmission loss. However, the brittleness of basalt led to a slight increase in the breakage rate during the preparation of the braided wire. The bending fatigue performance still met the standard but the margin decreased, while other properties remained good.

[0067] In Example 3, increasing the polyimide content to 40 parts enhanced yarn flexibility and hot-melt bonding, improved self-locking properties, slightly reduced dielectric constant, and slightly decreased transmission loss. However, due to the increased organic components, the shrinkage rate after long-term aging at 300°C was slightly greater than in Example 1, but still within the acceptable range.

[0068] In Example 4, the tension was increased to 1.8 / 1.2N, the braided layer was tighter, the internal stress field was stronger, the radial shrinkage rate after cooling reached 1.8%, the self-locking clamping force was greater, the outer diameter uniformity decreased slightly but was still within the tolerance, and other properties did not change significantly.

[0069] In Example 5, heat setting was completed at a lower temperature of 350°C and for a longer time of 5 seconds, which also achieved sufficient heat-melt bonding. This method has a milder thermal shock, less thermal impact on polyimide fibers, and good surface film quality.

[0070] In Example 6, a lower tempering temperature and a longer tempering time are used, which can release internal stress more gently. The closed film formed by the rapid cooling of the surface is denser, and the waterproof performance is maintained well. Other properties are the same as in Example 1.

[0071] In Example 7, the twist was reduced to 40 / 20 twists / 10cm, which improved the yarn softness and slightly reduced the overall bending radius of the cable. However, the braid porosity increased slightly. Through the hydrophobic compensation of the cross-linked interface film of the coupling agent, the waterproof rating still reached IP67, which reflects the redundant design of the interface treatment.

[0072] In Example 8, the curing temperature was increased to 320°C and the time was shortened to 5 minutes, resulting in a faster crosslinking reaction. The interfacial film performance was comparable to that of Example 1. The high-temperature, short-time process was more efficient in large-scale production, and other properties were not degraded.

[0073] In Comparative Example 1, the basalt fiber content was increased to 70 parts, while the polyimide fiber content and ceramicized silicone rubber fiber content were reduced to 10 parts. The excessively high proportion of inorganic rigid components in the yarn led to a significant increase in overall yarn brittleness, resulting in frequent fiber breakage during weaving and a rough sheath surface. During bending, due to the lack of a sufficient elastic buffer layer from polyimide, the inorganic fibers directly bore the stress, causing cracks to appear after 120 bends.

[0074] The flame retardant rating dropped from V-0 to V-1 for two main reasons. First, the content of ceramicized silicone rubber fiber decreased from 15 parts to 10 parts, which is insufficient to form a continuous and dense ceramicized barrier layer during combustion, thus losing its primary function as an active fire barrier. Second, the content of polyimide fiber decreased from 30 parts to 10 parts, significantly weakening its char-forming and heat-insulating auxiliary effects in the early stages of combustion, making it unable to synergistically form a complete carbon-ceramic composite fireproof layer with the ceramicized fiber. These two factors combined resulted in the flame retardant rating dropping to V-1.

[0075] The waterproof performance decreased from IP67 to IPX5. This was due to the excessively high proportion of basalt fiber, which increased yarn brittleness. Fiber breakage during weaving resulted in numerous micropores and surface roughness defects within the woven layer, compromising the density of the weave structure. Simultaneously, the reduced content of ceramicized silicone rubber fiber correspondingly decreased the number of active silanol sites on its surface that could form chemical bonds with the coupling agent, leading to a decline in the integrity and cross-linking continuity of the coupling agent interfacial film on the fiber surface. Under the combined effect of this decreased woven structure density and incomplete interfacial film, the woven layer could not form an effective continuous hydrophobic barrier, causing the waterproof rating to drop from IP67 to IPX5.

[0076] In Comparative Example 2, after the ceramicized silicone rubber fiber was completely removed, the flame retardant performance dropped from V-0 to V-1, proving that ceramicized silicone rubber fiber is irreplaceable in active fire protection. The waterproof performance decreased from IP67 to IPX6 because the ceramicized silicone rubber fiber surface contains polar groups such as active silanol groups. During coupling agent impregnation, these polar groups can chemically bond or strongly physically anchor with fluorinated silanes and epoxy silanes, promoting uniform grafting and cross-linking of the coupling agent on the fiber surface, which is beneficial for forming a continuous and dense hydrophobic interface film. After removing the ceramicized silicone rubber fiber, the hydrophilic sites on the basalt fiber surface in the braided layer are difficult to be completely covered by the coupling agent. The continuity of the coupling agent film layer among the three fibers (basalt / polyimide / aramid) decreases, resulting in a weakened hydrophobic sealing effect on the braided pores, and the waterproof rating decreased from IP67 to IPX6.

[0077] In Comparative Example 3, the amount of polyimide fiber was increased to 50 parts, and the proportion of organic components was too high. After long-term aging at 300℃, the cumulative amount of thermal shrinkage of organic fibers was large, which exceeded the constraint capacity of the inorganic skeleton, resulting in loosening and delamination of the sheath and failure of the self-locking structure.

[0078] The waterproof performance dropped from IP67 to IPX5 because the excessive polyimide content caused significant thermal shrinkage accumulation in the organic fibers during long-term aging at 300℃. This resulted in micro-delamination and loose gaps between the braided sheath and the shielding layer, as well as between fiber bundles within the braided layer. These gaps became channels for liquid water to penetrate axially and radially, disrupting the overall continuous barrier properties of the sheath layer. Although the coupling agent interfacial film itself may remain intact on the fiber surface, the macroscopic dimensional instability of the braided structure caused local cracking or separation of the interfacial film at braiding intersections and fiber contact points, failing to maintain a continuous hydrophobic barrier. Therefore, the aged cable showed water leakage in the IPX5 water spray test, and the waterproof rating dropped from IP67 to IPX5.

[0079] In Comparative Example 4, the tension of the winding spindle was increased to 2.5N, while the tension of the filler spindle was decreased to 0.5N. The excessive difference in spindle tension resulted in severe localized stress concentration during weaving, leading to wavy, uneven deformation on the sheath surface. The waterproof performance decreased due to surface unevenness and micro-cracks caused by stress concentration areas, with the waterproof rating dropping from IP67 to IPX5.

[0080] In Comparative Example 5, the temperature of 320℃ did not reach the melting point of thermoplastic fibers such as polyimide fibers (340℃). Effective heat-melting adhesion was not formed at the weaving intersections. After cooling, the radial shrinkage rate was only 0.2%, which did not meet the 0.5% self-locking criterion. The mesh structure was loose, and there was no effective clamping force between the sheath and the shielding layer. It separated rapidly under bending conditions.

[0081] In Comparative Example 6, there was no tempering to release stress and no rapid cooling to densify the surface, resulting in microcracks in the film, reducing the waterproof rating to IPX6. Under the hot state of 300℃, the microcracks propagated, and the surface quality deteriorated.

[0082] In Comparative Example 7, the twist was below the lower limit, the yarn cohesion was weak, the weaving gaps were too large, exceeding the limit of the hydrophobic film of the coupling agent to effectively seal, the waterproofing only reached IPX5, and the yarn abrasion resistance decreased, and it pilled after dynamic bending.

[0083] In Comparative Example 8, curing at 350℃ for 10 minutes exceeded the safe processing window for polyimide and aramid fibers. The fibers suffered heat damage and yellowing, and the interfacial film was partially degraded. The initial performance was acceptable, but after long-term aging, the interface deteriorated, leading to delamination and increased dielectric loss.

[0084] In summary, this embodiment achieves a synergistic unity of five core properties on the same flexible woven sheath: long-term heat resistance at 300℃, instantaneous fire resistance at 1000℃, IP67 waterproof rating, high flexibility and fatigue resistance, and structural self-locking. This combination of properties cannot be achieved individually by existing solid extruded sheaths, pure inorganic fiber woven sheaths, or simple blended woven sheaths.

[0085] This embodiment improves high-temperature mechanical properties through a composite braided structure. Brittle basalt fiber filaments are constrained in the yarn core as a load-bearing skeleton, polyimide fibers are wrapped as an elastic buffer intermediate layer, and ceramicized silicone rubber fibers and aramid fibers are twisted and wrapped as a functional outer layer. By distributing stress and wear resistance to different fiber components at the yarn structure level, the braided sheath can withstand 500 repeated bends with a bending radius of less than 5 times the outer diameter of the cable at 300°C without breakage or delamination. This solves the inherent defects of inorganic fiber braided layers, such as high brittleness and easy pulverization.

[0086] This embodiment forms a self-locking structure through zoned and graded tension control and online heat setting. During the weaving process, differential tension is applied to the winding spindle and the filling spindle to create an internal stress distribution within the weaving layer. Controlled heat setting is performed immediately after weaving, causing the thermoplastic fiber components at the weaving intersections to undergo surface micro-melting and mutual thermal fusion bonding. After cooling, a self-locking mesh cylinder structure with a continuous inward clamping force on the shielding layer is formed. It can permanently adhere to the shielding layer without the need for external adhesives, eliminating delamination, bulging, and slippage failures caused by differences in thermal expansion coefficients at high temperatures.

[0087] It should be noted that surface micro-melting refers to the process where, at the heat-setting temperature (350–380°C), the outermost layer of the thermoplastic fiber components at the weaving intersections softens and partially melts due to heat, extending 0.1–1 μm from the fiber surface towards the core. This causes interfacial fusion at the contact point between adjacent fibers. The characteristics of surface micro-melting are: the fiber core remains solid, without complete melting or flow; the fiber's morphology and mechanical skeleton are not lost; however, the fiber surface possesses sufficiently high molecular chain segment mobility, allowing the polymer chains on both sides of the contact point to diffuse and entangle at the interface, forming an integrated weld point upon cooling.

[0088] To achieve surface micro-melting, the polyimide fiber that plays a major role in hot-melt bonding in the thermoplastic fiber component should be a thermoplastic polyimide fiber, such as a copolymer polyimide or a thermoplastic polyimide with added thermoplastic meltable segments. Its softening point or melting point should be between 340 and 400°C, and its decomposition temperature should not be lower than 420°C. At a heat-setting temperature of 350–380°C, the surface of the thermoplastic polyimide fiber can enter a partially molten state, while the fiber core remains solid, meeting the process requirements for surface micro-melting.

[0089] As a supplement, the silicone rubber organic matrix contained in the ceramicized silicone rubber fiber can also soften at 350–380℃, which plays an auxiliary role in the hot melt bonding of the braided intersections. The high-temperature resistant aramid fiber does not melt at 350–380℃, and its role is to provide wear resistance and assist in the stability of the braided structure, without participating in surface micro-melting bonding.

[0090] This embodiment enhances the woven pore structure and waterproof function through coupling agent impregnation and drying treatment. A fluorinated silane and epoxy silane compound system is used, combined with vacuum impregnation and programmed step curing, to form a dense cross-linked interface film on the surface of multi-component fibers. This firmly bonds the hydrophilic inorganic fibers and hydrophobic organic fibers into one, giving the whole structure hydrophobic properties. This allows the high-density porous woven layer to achieve IP67 waterproof rating without a solid sealing layer. The waterproof performance of Examples 1-8 all met the standard, while Comparative Example 7 only reached IPX5 due to its low twist and large pores. This proves that the synergy between interface treatment and woven density is the key to achieving structural waterproofing.

[0091] This embodiment establishes a graded fire-retardant response mechanism by precisely defining the temperature window of the ceramicized fiber. The initial ceramicization temperature of the ceramicized silicone rubber fiber is limited to greater than 380°C, which is higher than the upper limit of the heat setting process temperature of 380°C. This ensures that no ceramicization reaction occurs during normal preparation and use, maintaining the flexibility of the sheath. Above 450°C, it completely transforms into a hard ceramic shell, actively forming a physical barrier that isolates oxygen and radiant heat under fire or instantaneous ultra-high temperature impact of 1000°C. The flame retardant ratings of Examples 1-8 all reach UL94 V-0 level with no dripping and no toxic fumes, while Comparative Example 2 only reaches V-1 level, proving the irreplaceable nature of this fiber in achieving V-0 flame retardancy.

[0092] In this embodiment, the process parameter windows have been verified by the examples and comparative examples to have clear criticality. Examples 1-8 all maintained full compliance with performance under different raw material ratios, tension parameters, heat setting parameters, tempering parameters, and twist parameters. Comparative examples 1-8 proved from the aspects of excessive raw materials, missing components, tension imbalance, insufficient temperature, and omitted steps that deviating from the parameter windows will lead to significant deterioration of one or more of the following properties: long-term heat aging resistance, structural self-locking, waterproof sealing, flame retardancy, or dynamic bending life.

[0093] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A manufacturing process for a novel high-temperature resistant fiber-braided coaxial cable, characterized in that, include: Using basalt fiber filaments as the core yarn, polyimide fibers are wrapped around the outer periphery to form an elastic intermediate layer. Ceramicized silicone rubber fibers and high-temperature resistant aramid fibers are mixed to form a composite braided yarn to wrap around the outer periphery of the elastic intermediate layer. The composite braided yarn is impregnated with a coupling agent and dried to form a cross-linked interface film on the surface of the composite braided yarn; Semi-finished products are prepared based on an inner conductor, a high-temperature resistant insulating layer, and a shielding layer; The treated composite braided yarn is used to braid the shielding layer of the semi-finished product. During the braiding process, the tension of several spindles of the braiding machine is controlled by dividing and grading the spindles, so that the spindles in the winding area and the spindles in the filling area are differentiated by the unwinding tension, so as to form an internal stress distribution in the braided layer. Downstream of the weaving point, the semi-finished product after weaving is heat-set. After the thermoplastic fiber components at the weaving intersection undergo surface micro-melting and heat-melting and bonding with each other, a tight sealing film is formed on the surface of the weaving layer. After the braided layer is cooled for a preset time, a self-locking mesh cylinder structure with a continuous inward clamping force is formed on the shielding layer to obtain a high-temperature resistant fiber braided coaxial cable.

2. The manufacturing process of the novel high-temperature resistant fiber braided coaxial cable according to claim 1, characterized in that, The polyimide fiber is wrapped around the surface of the core yarn with a twist of 40 to 60 twists / 10cm to obtain the elastic intermediate layer; After mixing the ceramicized silicone rubber fiber and the high-temperature resistant aramid fiber, the composite braided yarn is obtained by wrapping it in a mesh shape in the elastic intermediate layer with a twist of 20-30 twists / 10cm.

3. The manufacturing process of the novel high-temperature resistant fiber braided coaxial cable according to claim 2, characterized in that, The process of impregnating with coupling agent includes: A complex coupling agent containing perfluorooctyltriethoxysilane and KH-560 silane coupling agent in a mass ratio of 1:2 was selected, and nano-silica sol accounting for 5% of the total mass of the complex coupling agent was added as a film-forming aid.

4. The manufacturing process of the novel high-temperature resistant fiber braided coaxial cable according to claim 3, characterized in that, The drying process includes: During the impregnation of the coupling agent, the vacuum is drawn to -0.08 MPa and maintained for 15 to 30 minutes to allow the coupling agent solution to fully penetrate and displace the air in the fiber bundle. After low-temperature drying at 60–80°C, the temperature is raised to 280–320°C and maintained for 5–10 minutes to allow the coupling agent to undergo a cross-linking reaction and bond to the fiber surface.

5. The manufacturing process of the novel high-temperature resistant fiber braided coaxial cable according to claim 4, characterized in that, The process of preparing the semi-finished product includes: Between the high-temperature resistant insulation layer and the shielding layer, a polyimide film with a temperature resistance greater than or equal to 350°C is wrapped as a physical buffer layer. The outer surface of the shielding layer is coated with polyimide varnish and cured to form a thermally insulating interface.

6. The manufacturing process of the novel high-temperature resistant fiber braided coaxial cable according to claim 5, characterized in that, The weaving process includes: The braiding machine has an even number of spindles, and the number of spindles in the winding zone is equal to the number of spindles in the filling zone; The unwinding tension of the spindle in the winding zone of the braiding machine is adjusted to 1.3 to 1.8 N, and the unwinding tension of the spindle in the filling zone is adjusted to 0.8 to 1.2 N, thereby creating a tension difference between the winding zone and the filling zone to form an internal stress distribution in the braided structure.

7. The manufacturing process of the novel high-temperature resistant fiber braided coaxial cable according to claim 6, characterized in that, The heat setting process includes: The woven semi-finished product is fed into an induction heating tunnel and heated at 350-380°C for 3-5 seconds.

8. The manufacturing process of the novel high-temperature resistant fiber braided coaxial cable according to claim 7, characterized in that, The heat setting process also includes: The woven semi-finished product is passed through a tempering tunnel at 260-300°C for 15-30 seconds, and then the outer surface of the woven semi-finished product is rapidly cooled by a room temperature airflow to form a tightly sealed film on the surface of the woven layer.

9. The manufacturing process of the novel high-temperature resistant fiber braided coaxial cable according to claim 8, characterized in that, The process of determining whether a self-locking mesh cylinder structure has been formed includes: The initial outer diameter of the braided layer before cooling and the shrinkage outer diameter after cooling were collected to calculate the radial shrinkage rate. When the radial shrinkage rate is in the range of 0.5% to 2%, it is determined that the self-locking mesh cylinder structure has been formed.

10. A novel high-temperature resistant fiber-braided coaxial cable, obtained by the manufacturing process of the novel high-temperature resistant fiber-braided coaxial cable according to any one of claims 1-9, characterized in that, The raw materials for preparing the composite braided yarn are, by mass parts: The basalt fiber is 40-60 parts, the polyimide fiber is 20-40 parts, the ceramicized silicone rubber fiber is 10-30 parts, and the high-temperature resistant aramid fiber is 5-10 parts. The ceramicized silicone rubber fiber has an initial ceramicization temperature greater than 380°C and is completely transformed into a hard ceramic shell above 450°C.

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