Fire-resistant cable suitable for fire environment heating condition and preparation method of fire-resistant cable

Abstract

The invention relates to the technical field of cables, in particular to a fire-resistant cable suitable for a fire environment heating condition and a preparation method of the fire-resistant cable. The fire-resistant cable comprises an insulating wire core, a fire insulation layer and a sheath layer which are arranged from inside to outside. The fire insulation layer is made of ceramic silica gel cement; the ceramic silica gel cement is prepared from the following components in parts by weight: 20-40 parts of ceramic silica gel, 100-120 parts of methyl vinyl silicone rubber raw rubber, 30-50 parts of white carbon black, 4-6 parts of glass powder, 30-40 parts of aluminum oxide, 20-30 parts of zinc borate, 1-3 parts of zinc oxide, 30-40 parts of mica powder, 7-10 parts of dimethyl silicone oil and 0.3-0.5 part of a platinum catalyst. According to the invention, the mechanical strength and flexibility of the cable at high temperature are improved, and the high temperature resistance and electrical insulation performance of the fire insulation layer and the insulating layer are enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of cables, and in particular to a fire-resistant cable suitable for use in temperature-raising conditions in a fire environment and a preparation method thereof. Background Art

[0002] In modern buildings and industrial facilities, the safety performance of cables is crucial, especially in emergency situations such as fires. Cables need to maintain power transmission functions under fire conditions to ensure the normal operation of fire protection systems, emergency lighting and communication equipment, and facilitate personnel evacuation and fire rescue.

[0003] With the frequent occurrence of various fire accidents, huge losses of life and property have been caused. Therefore, the requirements for fire-resistant cables used in fire protection systems are constantly increasing. Fire-resistant cables are mainly used in crowded places such as residences, shopping malls, supermarkets, hospitals, theaters, and important engineering facilities with special requirements such as subways, airports, petrochemicals, and metallurgy. These crowded places and engineering facilities have high requirements for power transmission. At the same time, they are in special environments such as high temperature and high pressure or crowded with people. Fire-resistant cables are needed to ensure the safety of power transmission under fire conditions.

[0004] At present, the test method of fire-resistant cables cannot reflect the real fire scene, and there are significant differences between the fire scene and the test method. The main reasons are as follows: (1) In the fire test, the cable is laid horizontally as a single cable, while in reality, most cables are laid horizontally or vertically in bundles. (2) The fire test uses a single blowtorch with a length of 500 mm and a flame temperature of 750°C. The length of the cable burned is limited. For cables with large outer diameters, the flame cannot wrap around the cable and can only burn the bottom of the cable. In a fire, the flame will completely wrap around the cable, similar to heating with multiple blowtorches, and the flame temperature can reach over 1000°C. (3) The fire test time is 90 minutes, while a large fire can last for several hours or even more than ten hours. (4) The starting ambient temperature of the fire test is room temperature, and the ambient temperature is heated by the heat of the test flame. At the end of the test, the ambient temperature is less than 100°C. From the perspective of the fire development process, the fire intensity changes with time. The fire will change with the changes in the fire load, nature and distribution. The ambient temperature will also continue to rise with the development of the fire. Fire science research shows that when the fire reaches 180 minutes, the ambient temperature can exceed 1000°C.

[0005] Due to the above-mentioned differences between the test methods of fire-resistant cables and actual fire scenarios, although the existing fire-resistant cables can meet the test requirements, they cannot meet the use requirements in real fire environments. First, the existing fire-resistant cables lack mechanical strength and flexibility at high temperatures, which makes them easily damaged in fires. Secondly, the electrical properties of the cables will drop rapidly at high temperatures, affecting the continuous working ability of the cables and even losing their power supply capabilities. This will result in the fire-resistant cables not being able to function well in fires even though they meet the test requirements, thus losing the original intention of the fire-resistant cables. Therefore, the development of new fire-resistant cables that can withstand the heating conditions of fire environments is the development trend of fire-resistant cables. Summary of the invention

[0006] In view of the shortcomings of existing cables, the purpose of the present invention is to provide a fire-resistant cable suitable for use in fire environment temperature rise conditions and a preparation method thereof, which can provide higher safety and reliability in a fire environment. Through the structural design and material selection of the fire-resistant layer, insulating layer, fire-proof layer, cushion layer and sheath layer, the problems existing in the prior art are solved, the electrical performance of the cable at high temperatures is improved, the high temperature resistance of the fire-proof layer and the insulating layer is enhanced, and the manufacturing process is simplified to reduce costs. At the same time, by using ceramic silica gel mud and other high-performance materials with a specific formula, it is ensured that the cable can continue to work stably at high temperatures of 600 to 1200°C, thereby providing more reliable support for personnel evacuation and rescue work when a fire occurs.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] A fire-resistant cable suitable for use in fire environment temperature rise conditions, comprising: an insulating wire core, a fireproof layer and a sheath layer arranged from the inside to the outside, wherein the fireproof layer is made of ceramic silica gel mud; the ceramic silica gel mud is composed of the following parts by weight: 20-40 parts of ceramic silica gel, 100-120 parts of methyl vinyl silicone rubber raw rubber, 30-50 parts of white carbon black, 4-6 parts of glass powder, 30-40 parts of aluminum oxide, 20-30 parts of zinc borate, 1-3 parts of zinc oxide, 30-40 parts of mica powder, 7-10 parts of dimethyl silicone oil and 0.3-0.5 parts of platinum catalyst.

[0009] The present invention also provides a method for preparing the fire-resistant cable suitable for use in a fire environment under elevated temperature conditions, comprising:

[0010] Preparation of methyl vinyl silicone rubber; preparation of ceramic rubber: adding dimethyl silicone oil, glass powder and mica powder additives to the synthesized methyl vinyl silicone rubber, stirring evenly and then adding to an internal mixer for plasticization, discharging the material after plasticization evenly to obtain ceramic rubber; preparation of ceramic silica mud: adding the prepared ceramic rubber, silicone rubber raw rubber, white carbon black, catalyst, stabilizer, aluminum oxide and zinc borate into a rubber mixer for mixing and plasticization to obtain ceramic silica mud material; stranding soft copper wires in a regular arrangement on a frame stranding machine to obtain a stranded conductor; wrapping inorganic mineral insulating tape on the surface of the stranded conductor, the inorganic mineral insulating tape should be wrapped in an overlapping manner, the wrapping direction of each layer should be opposite, and the outermost layer should be to the right to obtain a fire-resistant conductor; extruding ceramic polyolefin material on the surface of the fire-resistant conductor to obtain an insulated wire core; extruding ceramic silica mud on the outside of the cable core to form a fire-proof layer, wrapping tape on the outside of the fire-proof layer to form a cushioning layer, and extruding sheath material on the outside of the cushioning layer.

[0011] One or more technical solutions provided by the present invention have at least the following technical effects or advantages:

[0012] The ceramic silica mud material of the cable fire insulation layer is heated and melted in the temperature range of 350-600℃ under flame ablation to form a viscous flow state, bonding the refractory filler and residual ash together. When the temperature exceeds 600℃, the silicon dioxide generated by the combustion of the refractory filler and the silicone rubber matrix undergoes a eutectic reaction to produce a dense silicate ceramic layer. The ceramic layer has excellent mechanical strength in the temperature range of 600-1200℃, and can withstand external damage such as vibration impact and water spray, thereby ensuring that the cable can be effectively protected during a fire. At the same time, the ceramic layer also has excellent heat insulation, which can prevent external flames and heat from spreading to the inside of the cable.

[0013] The cable adopts a fireproof and heat-insulating structural design. The insulation layer is made of ceramic polyolefin material, the fireproof layer is made of ceramic silica mud material, and the cushion layer is made of ceramic fire-resistant composite tape. These three materials can be sintered into a ceramic shell after flame ablation, blocking the flame and heat from spreading into the cable and protecting the internal structure. The insulation layer and the fire-resistant layer form a composite insulation layer, which improves the electrical insulation performance of the cable under flame conditions. A large amount of flame-retardant materials are used in the cable to improve the flame-retardant performance of the cable. In an exogenous fire, the cable does not spontaneously combust or support combustion, which can reduce the fire and smoke and reduce personal injury.

[0014] The fire-resistant layer of the cable adopts inorganic mineral insulating tape, and the insulating layer adopts extruded ceramic polyolefin material. The fire-resistant layer and the insulating layer constitute composite insulation, and both are fire-resistant and high-temperature resistant materials, which can maintain high electrical insulation performance under flame and high temperature conditions. The fire-insulating layer adopts extruded ceramic silica gel mud material, the cushioning layer adopts ceramic fire-resistant composite tape, and the sheath layer adopts halogen-free low-smoke flame-retardant polyolefin material with good crusting performance. Ceramic polyolefin material, ceramic silica gel mud material and ceramic fire-resistant composite tape have excellent fire-resistant and high-temperature resistant properties. When heat and flame burn, the surface sinters to form a ceramic layer, which isolates the flame and heat from transferring to the inside of the cable, and plays a role in fire and heat insulation. The fire-insulating and heat-insulating structural design of the insulating layer, fire-insulating layer and cushioning layer ensures that the cable can operate continuously and stably in a fire environment with rising temperatures, which buys time for rescue and escape.

[0015] Advantages of additional aspects of the present invention will be given in the following description, and in part will become obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments or technical solutions of the present application, the following briefly introduces the drawings required for the description of the embodiments or technical solutions. Obviously, the drawings described below are only some embodiments recorded in the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work. In addition, the spacing or size between each other is exaggerated to show the position of each part, and the schematic diagram is only used for illustration.

[0017] Figure 1 is a schematic diagram of a fire-resistant cable provided in Embodiment 1 of the present invention;

[0018] Figure 2 is a schematic diagram of a fire-resistant cable provided in Embodiment 2 of the present invention;

[0019] In the figure: 1. conductor; 2. fire-resistant layer; 3. insulating layer; 4. filling core; 5. fire-proof layer; 6. cushion layer; 7. outer sheath. DETAILED DESCRIPTION

[0020] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those of ordinary skill in the art to which the present invention belongs. In addition, it should also be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0021] Embodiment 1

[0022] like Figure 1As shown, the cable is a single-core cable. This embodiment has 1 insulated core, a copper conductor 1 arranged from the inside to the outside, the copper conductor 1 is formed by twisting multiple strands of fine copper wires, and a refractory layer 2 is wrapped flatly and densely on the copper conductor 1. The refractory layer 2 is an inorganic mineral insulating tape, and the inorganic mineral insulating tape is a composite structure of one or more of synthetic mica tape, calcined mica tape or coated mica tape. An insulating layer 3 is extruded on the refractory layer 2, and the insulating layer 3 is a ceramic polyolefin material. Ceramic silica gel mud is extruded outside the insulating layer 3 to form a fireproof layer 5, and a ceramic refractory composite tape is wrapped outside the fireproof layer 5 to form a cushion layer 6; a halogen-free, low-smoke, flame-retardant polyolefin material with good crusting performance is extruded outside the cushion layer 6 to form a sheath layer 7, and the sheath layer is preferably orange-red in color. The cable as a whole achieves properties such as fire resistance and flame retardancy.

[0023] The ceramic silica gel mud is composed of the following parts by weight: 20-40 parts of ceramic silica gel, 100-120 parts of methyl vinyl silicone rubber, 30-50 parts of white carbon black, 4-6 parts of glass powder, 30-40 parts of aluminum oxide (particle size>10 μm), 20-30 parts of zinc borate, 1-3 parts of zinc oxide, 30-40 parts of mica powder, 7-10 parts of dimethyl silicone oil, and 0.3-0.5 parts of platinum catalyst. The ceramic silica gel mud material of the present invention maintains a soft elastic state at room temperature, can be sintered into a self-supporting ceramic structure under high temperature calcination of not less than 600°C, can ensure that the cable still works continuously and stably at high temperatures of 600-1200°C, and has good mechanical properties, processing properties, flexibility and fire resistance.

[0024] After the sheath layer is burned by flames, the burning products can be sintered into a shell shape and attached to the cable surface, thus preventing the flame from spreading into the interior of the cable.

[0025] When the ceramic refractory composite tape of the cushion layer is heated under flame ablation and the temperature exceeds 500°C, the refractory silicone rubber in the composite tape is sintered into a porcelain-like body attached to the surface of the cable core, isolating the flame, heat and air from spreading into the cable core.

[0026] The ceramic silica mud material of the fireproof layer is heated and melted in the temperature range of 350-600℃ under flame ablation to form a viscous flow state, bonding the refractory filler and residual ash together. When the temperature exceeds 600℃, the silicon dioxide generated by the combustion of the refractory filler and the silicone rubber matrix undergoes a eutectic reaction to produce a dense silicate ceramic layer. The ceramic layer has excellent mechanical strength in the temperature range of 600-1200℃, and can withstand external damage such as vibration, impact, and water spray, thereby ensuring that the cable can be effectively protected throughout the fire process. At the same time, the ceramic layer also has excellent heat insulation, which can prevent external flames and heat from invading and spreading into the cable.

[0027] When the ceramic polyolefin of the insulating layer is sintered at a temperature exceeding 600°C, the ceramic shell formed is attached to the surface of the conductor. The residue after burning is a silicate material, which has good electrical insulation and can also prevent flames and heat from being transferred to the conductor. The insulating layer has the dual functions of insulation and fire and heat insulation.

[0028] The inorganic mineral insulating tape of the fire-resistant layer has excellent electrical insulation performance under high temperature conditions of 1200°C. The composite insulation layer composed of the fire-resistant layer and the insulating layer ensures that the insulated wire core can still operate continuously and stably in a high temperature environment.

[0029] Through the joint action of the sheath layer, lining layer, fire barrier layer, insulation layer and fire-resistant layer, the cable can continue to operate stably for a certain period of time when the temperature in the fire environment continues to rise, ensuring the evacuation of personnel and the implementation of rescue work.

[0030] The manufacturing steps of this cable are:

[0031] (1) Preparation of ceramic silica mud materials

[0032] S1: Preparation of methyl vinyl silicone rubber:

[0033] S101: Add the cis isomer of dimethyl disulfide into a reactor and add nitric acid for hydrolysis reaction. It needs to be heated by double-layer tubes. The heating temperature of the first layer of tubes is 150-160°C, and the heating temperature of the second layer of tubes is 160-170°C. The residence time of the material in each layer of tubes is 10-30 minutes.

[0034] S102: Add liquid silane into a reaction kettle, and add isopropyl peroxide as an initiator.

[0035] S103: In an inert gas atmosphere, the reaction system is heated to 180-200° C. and maintained for 3-5 hours. After the reaction is completed, the reaction product is cooled to 120-130° C. and washed with water at 1.2-1.3 kPa to remove by-products and unreacted products.

[0036] S104: Cool the cooled product to room temperature and dry it to obtain methyl vinyl silicone rubber. Perform silicone molding on the methyl vinyl silicone rubber to obtain raw rubber.

[0037] S2: Preparation of ceramic rubber:

[0038] Add dimethyl silicone oil, glass powder, mica powder and other additives to the methyl vinyl silicone rubber synthesized in step S1, stir evenly and add to an internal mixer for plasticization, and discharge the material after plasticization evenly to obtain a ceramic rubber material.

[0039] S3: Preparation of ceramic silica gel mud:

[0040] The ceramic rubber material obtained in step S2 is put into a rubber mixer with raw silicone rubber, white carbon black, a catalyst, a stabilizer, alumina, zinc borate, etc. for mixing and plasticizing to obtain a ceramic silica gel mud material.

[0041] S301: Pick up the ceramic rubber material in the formula, silicone rubber raw rubber, white carbon black, catalyst, stabilizer, aluminum oxide, and zinc borate according to the proportion, put them into a mixer for thorough mixing, at this time, the speed of the mixer needs to be controlled to 300-350rpm, and the mixing time is 15-20 minutes;

[0042] S302: Debug the temperature of each zone of the mixer. The reference temperature is set as follows: 30-40℃ for barrel zone 1, 40-45℃ for barrel zone 2, 40-45℃ for barrel zone 3, 45-50℃ for barrel zone 4, 45-55℃ for barrel zone 5, 40-50℃ for die head, 45-55℃ for mold. The mixer needs to run at no load for 5-10 minutes based on the reference temperature before the mixed material can be poured into the mixer. The extrudate from the mixer must be placed in the air to cool. Note that air circulation must be continued during the cooling process, and an impurity treatment device must be equipped to keep the air clean.

[0043] S303: The cooled micelles need to be sealed and stored to prevent water absorption and moisture;

[0044] S304: Check the quality of finished gel balls in each batch and require the gel balls to meet the technical requirements.

[0045] (2) Cable manufacturing:

[0046] S21: Twist the soft copper wires in a regular arrangement on a frame stranding machine to make a stranded conductor; wrap an inorganic mineral insulating tape on the surface of the stranded conductor, the inorganic mineral insulating tape should be wrapped in an overlapping manner, and the wrapping direction of each layer should be opposite, with the outermost layer facing right, to obtain a fire-resistant conductor; extrude ceramic polyolefin material on the surface of the fire-resistant conductor to obtain an insulated wire core.

[0047] S22: Ceramic silica gel mud is extruded outside the insulating wire core to form a fire insulation layer, and the fire insulation layer should have a certain thickness.

[0048] S23: The fire-insulating layer is wrapped with a wrapping tape to form a cushioning layer. The wrapping tape should be a ceramic fire-proof and fire-resistant composite tape.

[0049] S24: Orange-red halogen-free, low-smoke, flame-retardant polyolefin sheath material is extruded outside the cushion layer. The sheath material should have good crusting properties, adhere to the surface of the fireproof layer after carbonization in a flame environment, and will not fall off without external impact.

[0050] Embodiment 2

[0051] like Figure 2As shown, the cable is a multi-core cable. In this example, there are 5 insulated cores, which are composed of a copper conductor 1, a fire-resistant layer 2 wrapped around the copper conductor 1, and an insulating layer 3 extruded on the fire-resistant layer 2. The copper conductor 1 is formed by twisting multiple strands of fine copper wires, and the fire-resistant layer 2 is an inorganic mineral insulating tape, which is a composite structure of one or more of synthetic mica tape, calcined mica tape or coated mica tape; the insulating layer 3 is an extruded ceramic polyolefin material; the copper conductor 1, the fire-resistant layer 2, and the insulating layer 3 together constitute the insulating core, which are twisted into a cable core, and the central gap between the insulating cores of the cable core is filled with inorganic fibers 4, and the edge gaps are not filled; ceramic silica gel mud is extruded outside the cable core to form a fire insulation layer 5, and the ceramic silica gel mud fills the edge gaps of the cable core to form a certain thickness; the ceramic fire-resistant composite tape is wrapped outside the fire insulation layer 5 to form a cushion layer 6; the outermost layer is a sheath layer 7.

[0052] The ceramic silica gel mud described in the fireproof layer 5 is composed of the following parts by weight: 20-40 parts of ceramic silica gel, 100-120 parts of methyl vinyl silicone rubber, 30-50 parts of white carbon black, 4-6 parts of glass powder, 30-40 parts of aluminum oxide (particle size>10μm), 20-30 parts of zinc borate, 1-3 parts of zinc oxide, 30-40 parts of mica powder, 7-10 parts of dimethyl silicone oil, and 0.3-0.5 parts of platinum catalyst. The ceramic silica gel mud material of the present invention maintains a soft elastic state at room temperature, can be sintered into a self-supporting ceramic structure under high temperature burning of not less than 600°C, can ensure that the cable still works continuously and stably at high temperatures of 600-1200°C, and has good mechanical properties, processing properties, flexibility and fire resistance.

[0053] The manufacturing steps of this cable are:

[0054] (1) Preparation of ceramic silica mud materials

[0055] S1: Preparation of methyl vinyl silicone rubber:

[0056] S101: Add the cis isomer of dimethyl disulfide into a reactor and add nitric acid for hydrolysis reaction. It needs to be heated by double-layer tubes. The heating temperature of the first layer of tubes is 150-160°C, and the heating temperature of the second layer of tubes is 160-170°C. The residence time of the material in each layer of tubes is 10-30 minutes.

[0057] S102: Add liquid silane into a reaction kettle, and add isopropyl peroxide as an initiator.

[0058] S103: In an inert gas atmosphere, the reaction system is heated to 180-200° C. and maintained for 3-5 hours. After the reaction is completed, the reaction product is cooled to 120-130° C. and washed with water at 1.2-1.3 kPa to remove by-products and unreacted products.

[0059] S104: Cool the cooled product to room temperature and dry it to obtain methyl vinyl silicone rubber. Perform silicone molding on the methyl vinyl silicone rubber to obtain raw rubber.

[0060] S2: Preparation of ceramic rubber:

[0061] Add dimethyl silicone oil, glass powder, mica powder and other additives to the methyl vinyl silicone rubber synthesized in step S1, stir evenly and add to an internal mixer for plasticization, and discharge the material after plasticization evenly to obtain a ceramic rubber material.

[0062] S3: Preparation of ceramic silica gel mud:

[0063] The ceramic rubber material obtained in step S2 is put into a rubber mixer with raw silicone rubber, white carbon black, a catalyst, a stabilizer, alumina, zinc borate, etc. for mixing and plasticizing to obtain a ceramic silica gel mud material.

[0064] S301: Pick up the ceramic rubber material in the formula, silicone rubber raw rubber, white carbon black, catalyst, stabilizer, aluminum oxide, and zinc borate according to the proportion, put them into a mixer for thorough mixing, at this time, the speed of the mixer needs to be controlled to 300-350rpm, and the mixing time is 15-20 minutes;

[0065] S302: Debug the temperature of each zone of the mixer. The reference temperature is set as follows: 30-40℃ for barrel zone 1, 40-45℃ for barrel zone 2, 40-45℃ for barrel zone 3, 45-50℃ for barrel zone 4, 45-55℃ for barrel zone 5, 40-50℃ for die head, 45-55℃ for mold. The mixer needs to run at no load for 5-10 minutes based on the reference temperature before the mixed material can be poured into the mixer. The extrudate from the mixer must be placed in the air to cool. Note that air circulation must be continued during the cooling process, and an impurity treatment device must be equipped to keep the air clean.

[0066] S303: The cooled micelles need to be sealed and stored to prevent water absorption and moisture;

[0067] S304: Check the quality of finished gel balls in each batch and require the gel balls to meet the technical requirements.

[0068] (2) Cable manufacturing:

[0069] S21: Twist the soft copper wires in a regular arrangement on a frame stranding machine to make a stranded conductor; wrap an inorganic mineral insulating tape on the surface of the stranded conductor, the inorganic mineral insulating tape should be wrapped in an overlapping manner, and the wrapping direction of each layer should be opposite, with the outermost layer facing right, to obtain a fire-resistant conductor; extrude ceramic polyolefin material on the surface of the fire-resistant conductor to obtain an insulated wire core.

[0070] Other insulated wire cores are prepared in sequence; color strips are added to the insulating layer during extrusion, and the insulated wire cores are identified by yellow, green, red, blue and black color matching.

[0071] S22: Arrange the insulated wire cores in a clockwise direction in the order of yellow, green, red, blue and black, and twist them into a cable core on a cabling machine. The central gap between the insulated wire cores of the cable core is filled with inorganic fiber material, which should not react with the insulating material, and the edge gaps are not filled.

[0072] S23: Ceramic silica gel is extruded outside the cable core to form a fire insulation layer. The fire insulation layer should fill the edge gaps of the cable core and form a certain thickness.

[0073] S24: A wrapping tape is wrapped around the fire-insulating layer to form a cushioning layer, and the wrapping tape is a ceramicized refractory composite tape.

[0074] S25: Extrusion of orange-red halogen-free low-smoke flame-retardant polyolefin sheath material on the outside of the cushion layer. The sheath material should have good crusting properties, adhere to the surface of the cushion layer after carbonization in a flame environment, and not fall off without external impact.

[0075] Although the above describes the specific implementation mode of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without creative work are still within the scope of protection of the present invention.

Claims

1. A fire-resistant cable suitable for use in fire environment with elevated temperature, characterized in that: include: An insulating wire core, a fireproof layer, a cushion layer and a sheath layer are arranged from the inside to the outside, wherein the fireproof layer is made of ceramic silica gel mud; The ceramic silica gel mud is composed of the following parts by weight: 20-40 parts of ceramic silica gel, 100-120 parts of methyl vinyl silicone rubber, 30-50 parts of white carbon black, 4-6 parts of glass powder, 30-40 parts of aluminum oxide, 20-30 parts of zinc borate, 1-3 parts of zinc oxide, 30-40 parts of mica powder, 7-10 parts of dimethyl silicone oil, and 0.3-0.5 parts of platinum catalyst.

2. The fire-resistant cable suitable for use in fire environment temperature rise conditions according to claim 1, characterized in that: The insulated wire core comprises a conductor, a fire-resistant layer and an insulating layer arranged from the inside to the outside, the conductor is formed by twisting a plurality of copper wires, the fire-resistant layer is formed by wrapping an inorganic mineral insulating tape, and the insulating layer is an extruded ceramic polyolefin material.

3. The fire-resistant cable suitable for use in fire environment temperature rise conditions according to claim 1, characterized in that: The fire-resistant layer is a wrapped structure of inorganic mineral insulating tape, and the inorganic mineral insulating tape is a composite structure of one or more of synthetic mica tape, calcined mica tape or coated mica tape.

4. The fire-resistant cable suitable for use in fire environment temperature rise conditions according to claim 1, characterized in that: The insulating layer is a ceramic polyolefin material coated on the outside of the fire-resistant layer in an extrusion manner.

5. The fire-resistant cable suitable for use in fire environment temperature rise conditions according to claim 1, characterized in that: The number of the insulating cores is one or more, and the multiple insulating cores are twisted into a cable core. A filling core is arranged at the center of the cable core, and the filling core is inorganic fiber.

6. The fire-resistant cable suitable for use in fire environment temperature rise conditions according to claim 1, characterized in that: A lining layer is arranged outside the fire-insulating layer, and the lining layer is a wrapped ceramicized refractory composite belt.

7. The fire-resistant cable suitable for use in elevated temperature conditions in a fire environment as claimed in claim 1, characterized in that: The sheath layer is an extruded halogen-free, low-smoke, flame-retardant polyolefin sheath material.

8. A method for preparing a fire-resistant cable suitable for use in elevated temperature conditions in a fire environment as claimed in any one of claims 1 to 7, characterized in that: include: Preparation of methyl vinyl silicone rubber; Preparation of ceramic rubber: adding dimethyl silicone oil, glass powder, and mica powder additives to the synthesized methyl vinyl silicone rubber, stirring evenly, adding the mixture to an internal mixer for plasticizing, and discharging the mixture after plasticizing evenly to obtain a ceramic rubber; Preparation of ceramic silica gel mud: adding the prepared ceramic rubber, silicone rubber raw rubber, white carbon black, a catalyst, a stabilizer, alumina, and zinc borate to a rubber mixer for mixing and plasticizing to obtain a ceramic silica gel mud material; The soft copper wires are twisted in a regular arrangement on a frame stranding machine to form a twisted conductor; the inorganic mineral insulating tape is wrapped around the surface of the twisted conductor. The inorganic mineral insulating tape should be wrapped in an overlapping manner, and the wrapping direction of each layer should be opposite, with the outermost layer to the right, to obtain a fire-resistant conductor; ceramic polyolefin material is extruded on the surface of the fire-resistant conductor to obtain an insulated wire core; ceramic silica gel mud is extruded outside the cable core to form a fire insulation layer, and a tape is wrapped outside the fire insulation layer to form a cushion layer, and a sheath material is extruded outside the cushion layer.

9. The preparation method according to claim 8, characterized in that: Preparation of methyl vinyl silicone rubber includes: The cis isomer of dimethyl disulfide is added to a reactor and nitric acid is added to perform a hydrolysis reaction, which needs to be heated by a double-layer tube array, the heating temperature of the first layer of tube array is 150-160° C., the heating temperature of the second layer of tube array is 160-170° C., and the residence time of the material in each layer of tube array is 10-30 minutes; liquid silane is added to the reactor, and isopropyl peroxide is added as an initiator; in an inert gas protective atmosphere, the reaction system is heated to 180-200° C. and maintained for 3-5 hours; after the reaction is completed, the reaction product is cooled to 120-130° C. and washed with water at 1.2-1.3 kPa to remove by-products and unreacted products; the cooled product is cooled to room temperature and dried to obtain methyl vinyl silicone rubber; the methyl vinyl silicone rubber is subjected to silicone rubber compression molding to obtain raw rubber; The preparation of ceramicized silica gel mud includes: picking up the ceramicized rubber material in the formula and silicone rubber raw rubber, white carbon black, catalyst, stabilizer, aluminum oxide, and zinc borate according to the ratio, and putting them into a mixer for thorough mixing. At this time, the rotation speed of the mixer needs to be controlled at 300-350rpm, and the mixing time is 15-20 minutes; the temperature of each zone of the mixer is adjusted, and the reference temperature is set as: 30-40°C for the first zone of the barrel, 40-45°C for the second zone of the barrel, 40-45°C for the third zone of the barrel, 45-50°C for the fourth zone of the barrel, 45-55°C for the fifth zone of the barrel, 40-50°C for the head, and 45-55°C for the mold; the mixer needs to run at no load for 5-10 minutes on the basis of the reference temperature, and then pour the mixed material into the mixer, and the extrudate from the mixer needs to be placed in the air to cool, and the cooled rubber mass is sealed and stored.

10. The preparation method according to claim 8, characterized in that: Before extruding the fire insulation layer, multiple insulated wire cores are arranged in a circular ring shape and twisted into a cable core on a cabling machine, and the central gaps between the insulating wire cores of the cable core are filled with inorganic fiber materials.

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