Fire-resistant cable, ceramic silicone rubber insulating material and preparation method thereof

Abstract

The invention discloses a fire-resistant cable, a ceramizable silicone rubber insulating material and a preparation method of the ceramizable silicone rubber insulating material, and relates to the technical field of cable materials.The ceramizable silicone rubber insulating material comprises, by weight, 100 parts of silicone rubber; 0.5-2 parts of a vulcanizing agent; 25 to 30 parts of a reinforcing agent; 5-8 parts of a fluxing agent; 45 to 50 parts of a porcelainized filler; 30 to 40 parts of a flame retardant; 0.5 to 1 part of a surface treating agent; and 5-20 parts of a stabilizer. The ceramic filler interacts at high temperature to form a compact ceramic layer, so that the fire resistance of the fire-resistant cable after ablation can be improved. And the silicone rubber has good high temperature resistance, and by combining the effects of the porcelainized filler and the fluxing agent, the material can keep stable insulating property at high temperature, and insulating property reduction caused by ablation is prevented. A layer of hydrophobic protective film is formed on the surface of the material through the surface treating agent, so that the reduction of the insulating property of the fire-resistant cable caused by damp can be reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of cable materials, and particularly relates to a fire-resistant cable, a ceramizable silicone rubber insulating material and a preparation method thereof. Background Art

[0002] Ordinary fire-resistant cables generally use mica tape as the fire-resistant layer material to make the insulating layer. However, due to the limitations of the process conditions of the fire-resistant cable wound with mica tape, defects often occur at the joints. After the fire-resistant cable is ablated, the insulating layer made of mica tape in the cable will become brittle and fall off, resulting in a decline in the fire-resistant performance of the fire-resistant cable. And during the fire fighting process, the insulating layer of the fire-resistant cable is prone to lose its insulation due to moisture absorption by spraying. Summary of the Invention

[0003] The main object of the present invention is to propose a fire-resistant cable, a ceramizable silicone rubber insulating material and a preparation method thereof, aiming to solve the technical problems that the fire-resistant performance of the fire-resistant cable is prone to decline after being ablated, and the fire-resistant cable is prone to lose its insulation due to moisture absorption by spraying.

[0004] To achieve the above object, the ceramizable silicone rubber insulating material proposed by the present invention, by weight, the ceramizable silicone rubber insulating material includes:

[0005] 100 parts of silicone rubber;

[0006] 0.5 part to 2 parts of vulcanizing agent;

[0007] 25 parts to 30 parts of reinforcing agent;

[0008] 5 parts to 8 parts of flux;

[0009] 45 parts to 50 parts of ceramicizing filler;

[0010] 30 parts to 40 parts of flame retardant;

[0011] 0.5 part to 1 part of surface treatment agent;

[0012] 5 parts to 20 parts of stabilizer.

[0013] In an embodiment, the silicone rubber is methyl vinyl silicone raw rubber, and the vinyl content in the methyl vinyl silicone raw rubber is 0.03% to 0.04%.

[0014] In an embodiment, the vulcanizing agent is 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane.

[0015] In an embodiment, the reinforcing agent is fumed silica.

[0016] In one embodiment, the flux is low-melting glass powder, the softening point of the low-melting glass powder is 480 °C, and the particle size of the low-melting glass powder is 800 mesh to 1000 mesh.

[0017] In one embodiment, by weight, the ceramizable filler includes:

[0018] 18 parts to 22 parts of mica;

[0019] 3 parts to 7 parts of glass microspheres;

[0020] 10 parts to 20 parts of tetragonal zirconia powder;

[0021] 5 parts to 10 parts of halloysite.

[0022] In one embodiment, the flame retardant is magnesium hydroxide;

[0023] and / or;

[0024] The surface treatment agent is vinyltrimethylsilane.

[0025] In one embodiment, the stabilizer is dimethyl silicone oil, and the viscosity of the dimethyl silicone oil at 25 °C is 350 mm 2 / s.

[0026] The present invention also provides a method for preparing a ceramizable silicone rubber insulating material, and the preparation method includes:

[0027] Add 100 parts of silicone rubber into a two-roll open mill, and carry out intensive mixing according to the front and rear roll speed ratio of 1:1.22 of the two-roll open mill to soften it;

[0028] Add 5 parts to 20 parts of stabilizer, 0.5 part to 1 part of surface treatment agent, 30 parts to 40 parts of flame retardant, 45 parts to 50 parts of ceramizable filler, 25 parts to 30 parts of reinforcing agent, 5 parts to 8 parts of flux, and 0.5 part to 2 parts of vulcanizing agent into the two-roll open mill in sequence, and continuously carry out intensive mixing at a temperature of 35 °C to 45 °C for 10 min to 30 min.

[0029] The present invention also provides a fire-resistant cable, which includes a sheath and a plurality of cable cores. The sheath is sleeved outside the plurality of cable cores, and an insulating layer is wrapped outside each cable core, and the material of the insulating layer is the above-mentioned ceramizable silicone rubber insulating material.

[0030] In one embodiment, the cable core in the fire-resistant cable is formed by stranding at least 19 conductive cores. The conductive core is a tinned copper single wire, the diameter of the tinned copper single wire is less than or equal to 2.62 mm, and the elongation rate of the tinned copper single wire is 23% to 27%.

[0031] In one embodiment, the cable core includes a first battery core layer and a second battery core layer. The second battery core layer wraps around the outer periphery of the first battery core layer. The first battery core layer is formed by stranding 7 conductive cores in a 1+6 structure. The stranding pitch of the first battery core layer is 113 mm to 156 mm. The second battery core layer is formed by stranding 12 conductive cores. The stranding pitch of the second battery core layer is 138 mm to 163 mm.

[0032] In one embodiment, the thickness of the insulating layer is 1.6 mm to 1.8 mm.

[0033] In one embodiment, a halogen-free low-smoke flame-retardant glass fiber filling rope is further provided inside the sheath. The halogen-free low-smoke flame-retardant glass fiber filling rope is located between the cable core and the sheath.

[0034] In one embodiment, a wrapping layer is further provided inside the sheath. The wrapping layer wraps around the outer peripheries of the halogen-free low-smoke flame-retardant glass fiber filling rope and the insulating layers of the plurality of cable cores.

[0035] Through the interaction of the ceramizing fillers at high temperatures, the technical solution of the present invention can form a dense ceramic layer. This ceramic layer can effectively isolate oxygen and heat, significantly improving the fire resistance of the ceramizable silicone rubber insulating material provided by the present invention after ablation. And the silicone rubber itself has good high-temperature resistance. Combining the effects of the ceramizing fillers and the fluxing agent enables the ceramizable silicone rubber insulating material provided by the present invention to maintain stable insulating performance at high temperatures, preventing the decline of insulating performance caused by ablation. And by forming a water-repellent protective film on the material surface with a surface treatment agent, it can effectively prevent the penetration of moisture, improving the waterproof performance of the ceramizable silicone rubber insulating material provided by the present invention. Through the synergistic effect of the reinforcing agent and the vulcanizing agent, the tensile strength and elongation at break of the ceramizable silicone rubber insulating material provided by the present invention can be improved, thereby enhancing the mechanical properties of the ceramizable silicone rubber insulating material provided by the present invention.

[0036] Furthermore, applying the ceramifiable silicone rubber insulating material of the present invention to a fire-resistant cable, the fire-resistant cable can form a dense ceramic layer outside the cable core through the interaction of ceramifying fillers at high temperatures. This ceramic layer can effectively isolate oxygen and heat, protect the cable core inside the fire-resistant cable, and significantly improve the fire-resistant performance of the fire-resistant cable provided by the present invention after ablation. Moreover, silicone rubber itself has good high-temperature resistance. Combining the effects of ceramifying fillers and fluxes enables the fire-resistant cable provided by the present invention to maintain stable insulating performance at high temperatures and prevent the decline of insulating performance caused by ablation. By forming a water-repellent protective film on the material surface through a surface treatment agent, the penetration of moisture can be effectively prevented, and the waterproof performance of the fire-resistant cable provided by the present invention can be effectively improved. This enables the fire-resistant cable provided by the present invention to still maintain good insulating performance under the condition of being sprayed and getting wet, and reduce the decline of insulating performance caused by moisture. Through the synergistic effect of a reinforcing agent and a vulcanizing agent, the tensile strength and elongation at break of the material can be improved, enhancing the mechanical properties of the fire-resistant cable provided by the present invention. This enables the fire-resistant cable provided by the present invention to better withstand mechanical stress in a fire environment and reduce the risk of insulation failure caused by mechanical damage. Brief Description of the Drawings

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0038] Figure 1 It is a schematic flowchart of an embodiment of the preparation method of the ceramifiable silicone rubber insulating material provided by the present invention;

[0039] Figure 2 It is a schematic structural diagram of an embodiment of the fire-resistant cable provided by the present invention.

[0040] Explanation of the reference numerals in the drawings:

[0041] 100, fire-resistant cable; 10, sheath; 20, cable core; 21, conductive core; 30, insulating layer; 40, wrapping layer; 50, halogen-free low-smoke flame-retardant glass fiber filling rope.

[0042] The realization, functional characteristics, and advantages of the object of the present invention will be further described in conjunction with the embodiments and with reference to the drawings. Detailed Embodiments

[0043] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts belong to the scope of protection of the present invention.

[0044] It should be noted that if there are directional indications (such as up, down, left, right, front, back...) involved in the embodiments of the present invention, the directional indications are only used to explain the relative positional relationship and movement conditions between components in a certain specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0045] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if "and / or" or "and / or" appears throughout the text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or a solution that satisfies both A and B at the same time. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0046] In this application, when it comes to numerical intervals (i.e., numerical ranges), unless otherwise specified, the distribution of the optional numerical values within the numerical interval is considered continuous and includes the two numerical endpoints of the numerical interval (i.e., the minimum value and the maximum value), as well as each numerical value between these two numerical endpoints. Unless otherwise specified, when the numerical interval only refers to the integers within the numerical interval, it includes the two endpoint integers of the numerical range, as well as each integer between the two endpoints, which is equivalent to directly listing each integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be combined. In other words, unless otherwise specified, the numerical ranges disclosed in this application should be understood to include any and all sub-ranges subsumed therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, a percentage, a ratio, etc. The "numerical interval" allows for a broad inclusion of quantitative intervals such as percentage intervals, ratio intervals, and ratio value intervals.

[0047] The present invention provides a ceramifiable silicone rubber insulating material.

[0048] In one embodiment of the present invention, the ceramicizable silicone rubber insulating material comprises, by weight:

[0049] Silicone rubber 100 parts;

[0050] 0.5 to 2 parts of vulcanizing agent;

[0051] 25 to 30 parts of reinforcing agent;

[0052] 5 to 8 parts of flux;

[0053] 45 to 50 parts of porcelain filler;

[0054] 30 to 40 parts of flame retardant;

[0055] 0.5 to 1 part of surface treatment agent;

[0056] 5 to 20 parts of stabilizer.

[0057] It is understandable that the number of vulcanizing agents can be any number of 0.5 to 2 parts, for example, 0.5, 1, 1.5 or 2 parts. The number of reinforcing agents can be any number of 25 to 30 parts, for example, 25, 26, 27, 28, 29 or 30 parts. The number of fluxing agents can be any number of 5 to 8 parts, for example, 5, 6, 7 or 8 parts. The number of ceramic fillers can be any number of 45 to 50 parts, for example, 45, 46, 47, 48, 49 or 50 parts. The number of flame retardants can be any number of 30 to 40 parts, for example, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39 or 40 parts. The number of parts of the stabilizer can be 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts or 20 parts.

[0058] The ceramizable silicone rubber insulating material provided by the present invention is prepared with the above specific components and ratios. The ceramizable silicone rubber insulating material provided by the present invention prepared with the specific components and ratios can form a dense ceramic layer through the interaction of ceramicizing fillers at high temperatures. This ceramic layer can effectively isolate oxygen and heat, significantly improving the fire resistance of the ceramizable silicone rubber insulating material provided by the present invention after ablation. And the silicone rubber itself has good high-temperature resistance. Combining the effects of ceramicizing fillers and fluxes, the ceramizable silicone rubber insulating material provided by the present invention can maintain stable insulating performance at high temperatures, preventing the decline of insulating performance caused by ablation. And a water-repellent protective film is formed on the material surface through a surface treatment agent, which can effectively prevent the penetration of moisture and improve the waterproof performance of the ceramizable silicone rubber insulating material provided by the present invention. Through the synergistic effect of a reinforcing agent and a vulcanizing agent, the tensile strength and elongation at break of the ceramizable silicone rubber insulating material provided by the present invention can be improved, thereby improving the mechanical properties of the ceramizable silicone rubber insulating material provided by the present invention.

[0059] The ceramizable silicone rubber insulating material provided by the present invention can be applied to structures such as cables, motors, transformers, or batteries. In this embodiment, the application of the ceramizable silicone rubber insulating material to a fire-resistant cable 100 is taken as an example for illustration.

[0060] In one embodiment, the fire-resistant cable 100 includes a sheath 10 and a plurality of cable cores 20. The sheath 10 is sleeved outside the plurality of cable cores 20, and an insulating layer 30 is wrapped around each cable core 20. The material of the insulating layer 30 is the above-mentioned ceramizable silicone rubber insulating material.

[0061] In the insulating layer of the fire-resistant cable 100 provided by the present invention, the ceramic fillers interact with each other at high temperatures, and a dense ceramic layer can be formed outside the cable core 20. This ceramic layer can effectively isolate oxygen and heat, protect the cable core 20 inside the fire-resistant cable 100, and significantly improve the fire-resistant performance of the fire-resistant cable 100 provided by the present invention after ablation. Moreover, silicone rubber itself has good high-temperature resistance. Combining the effects of ceramic fillers and fluxes enables the fire-resistant cable 100 provided by the present invention to maintain stable insulating performance at high temperatures and prevent the decline of insulating performance caused by ablation. By forming a water-repellent protective film on the material surface with a surface treatment agent, the penetration of moisture can be effectively prevented, and the waterproof performance of the fire-resistant cable 100 provided by the present invention can be effectively improved. This enables the fire-resistant cable 100 provided by the present invention to still maintain good insulating performance under the condition of being sprayed and getting wet, and reduces the decline of insulating performance caused by moisture. Through the synergistic effect of the reinforcing agent and the vulcanizing agent, the tensile strength and elongation at break of the material can be improved, and the mechanical properties of the fire-resistant cable 100 provided by the present invention are enhanced. This enables the fire-resistant cable 100 provided by the present invention to better withstand mechanical stress in a fire environment and reduces the risk of insulation failure caused by mechanical damage.

[0062] In an embodiment of the present invention, the silicone rubber is methyl vinyl silicone raw rubber, and the vinyl content in the methyl vinyl silicone raw rubber is 0.03% - 0.04%.

[0063] The vinyl content in the methyl vinyl silicone raw rubber can be any content within 0.03% - 0.04%. For example, the content can be 0.03%, 0.032%, 0.034%, 0.036%, 0.038% or 0.04%.

[0064] Specifically, methyl vinyl silicone raw rubber has excellent high-temperature resistance characteristics. The silicon-oxygen bond (Si-O) in its molecular structure has a very high bond energy, enabling the material to maintain a stable chemical structure in a high-temperature environment. When used in the cable insulating layer 30, even under high-temperature conditions of 950°C - 1000°C, the methyl vinyl silicone raw rubber can effectively prevent the cable core 20 of the fireproof cable from being ablated and maintain the fire-resistant performance of the fire-resistant cable 100. And when the vinyl content in the methyl vinyl silicone raw rubber is controlled within 0.03% - 0.04%, the high-methyl vinyl silicone raw rubber has better fire-resistant performance.

[0065] In an embodiment of the present invention, the vulcanizing agent is 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane.

[0066] Specifically, using 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane as a vulcanizing agent can initiate a cross-linking reaction in silicone rubber to form a three-dimensional network structure. This cross-linked structure significantly improves the mechanical properties of silicone rubber, including tensile strength, tear strength, and hardness, thereby enhancing the mechanical strength of the ceramifiable silicone rubber insulating material provided by the present invention. Moreover, the cross-linked silicone rubber is not prone to thermal degradation or softening in a high-temperature environment, and its physical and chemical properties are relatively stable. This is crucial for the reliable operation of the cable in a high-temperature environment. Even under high-temperature conditions of 950°C to 1000°C, it can still effectively maintain the insulation performance of the cable.

[0067] In an embodiment of the present invention, the reinforcing agent is fumed silica. Fumed silica has a high specific surface area and excellent reinforcing properties, which can significantly improve the tensile strength, tear strength, and hardness of silicone rubber. And fumed silica can improve the heat resistance of silicone rubber, enabling the mechanical strength of the ceramifiable silicone rubber insulating material provided by the present invention to maintain stable physical and chemical properties even under high-temperature conditions of 950°C to 1000°C. This contributes to the reliable operation of the fire-resistant cable 100 under high-temperature conditions of 950°C to 1000°C, especially in extreme situations such as fires, to maintain the insulation performance of the cable.

[0068] In an embodiment of the present invention, the flux is low-melting-point glass powder, the softening point of the low-melting-point glass powder is 480°C, and the particle size of the low-melting-point glass powder is 800 mesh to 1000 mesh.

[0069] The particle size of the low-melting-point glass powder can be any mesh number from 800 mesh to 1000 mesh. For example, the particle size of the low-melting-point glass powder can be 800 mesh, 850 mesh, 900 mesh, 950 mesh, or 1000 mesh.

[0070] Specifically, the low-melting-point glass powder with a particle size of 800 mesh to 1000 mesh has good dispersibility and can be evenly distributed in silicone rubber, avoiding agglomeration or local excess. This helps to obtain a ceramifiable silicone rubber insulating material with consistent quality during the preparation process, reducing performance differences and defects caused by uneven flux distribution. The low-melting-point glass powder with a softening point of 480°C can quickly melt when the silicone rubber encounters fire, timely filling the tiny pores and cracks generated during the ceramification process to form a uniform and dense glassy protective layer. And in a high-temperature environment, the low-melting-point glass powder with a softening point of 480°C can play a fluxing role earlier, absorbing a large amount of heat through melting and flowing, slowing down the overall heating rate of the material, thereby extending the service life of the cable under high-temperature conditions of 950°C to 1000°C.

[0071] In an embodiment of the present invention, by weight, the ceramifying filler includes:

[0072] 18 parts to 22 parts of mica;

[0073] 3 to 7 parts of glass microspheres;

[0074] 10 to 20 parts of tetragonal zirconia powder;

[0075] 5 to 10 parts of halloysite.

[0076] The number of parts of mica can be any number from 18 to 22 parts. For example, the number of parts of mica can be 18 parts, 19 parts, 21 parts or 22 parts. The number of parts of glass microspheres can be any number from 3 to 7 parts. For example, the number of parts of glass microspheres can be 3 parts, 4 parts, 5 parts, 6 parts or 7 parts. The number of parts of tetragonal zirconia powder can be any number from 10 to 20 parts. For example, the number of parts of tetragonal zirconia powder can be 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts or 20 parts. The number of parts of halloysite can be any number from 5 to 10 parts. For example, the number of parts of halloysite can be 5 parts, 6 parts, 7 parts, 8 parts, 9 parts or 10 parts.

[0077] Specifically, the ceramifying filler is composed of the above specific components and ratios. Under this specific component and ratio, due to the layered structure of mica, it can maintain the stability of its structure at high temperatures. When the flux melts, the mica flakes can be wrapped by the glassy substance to form a layered ceramic structure. The layered structure of mica helps to improve the mechanical strength and insulation performance of the ceramic layer. Glass microspheres can interact with the molten flux at high temperatures to form a uniform glassy substance. The addition of glass microspheres can increase the density and hardness of the ceramic layer, and at the same time, its smooth surface helps to reduce the accumulation of charges and improve the insulation performance. Tetragonal zirconia powder has a high melting point and high hardness, and can maintain the stability of its structure at high temperatures. When the flux melts, the tetragonal zirconia powder can be evenly dispersed in the glassy substance to form a strong ceramic phase, significantly improving the mechanical strength and high-temperature resistance of the ceramic layer. Halloysite has good adsorption properties and a flaky structure, and can interact with the molten flux and other fillers at high temperatures to form a dense ceramic layer. The flaky structure of halloysite helps to improve the toughness and impact resistance of the ceramic layer.

[0078] In an embodiment of the present invention, the flame retardant is magnesium hydroxide.

[0079] Specifically, when magnesium hydroxide is heated to 340°C to 490°C, it decomposes and releases water vapor. The released water vapor can absorb a large amount of heat, effectively reducing the temperature around the combustible material, thereby playing a flame retardant role. And after magnesium hydroxide is decomposed, magnesium oxide (MgO) is formed, thus generating a strong heat insulation protective layer on the surface of the ceramifiable silicone rubber insulating material. This heat insulation protective layer can effectively isolate air and prevent oxygen from entering, further playing a flame retardant role.

[0080] In an embodiment of the present invention, the surface treatment agent is vinyltrimethylsilane.

[0081] Specifically, vinyltrimethylsilane can significantly improve the adhesion between silicone rubber and ceramifying filler. It forms a uniform polymer film on the surfaces of silicone rubber and ceramifying filler, enabling chemical bonding between the two, thereby enhancing the integrity and stability of the ceramifiable silicone rubber insulating material. And vinyltrimethylsilane can form a hydrophobic protective film on the surface of the ceramifiable silicone rubber insulating material, effectively preventing the penetration of moisture, and can effectively improve the waterproof performance of the ceramifiable silicone rubber insulating material.

[0082] In an embodiment of the present invention, the stabilizer is dimethyl silicone oil, and the viscosity of dimethyl silicone oil at 25°C is 350 mm 2 / s.

[0083] Specifically, the chemical properties of dimethyl silicone oil are relatively stable, and it is not easily decomposed or deteriorated at high temperatures, which can effectively prevent the performance of the material from decreasing due to thermal aging. And the viscosity of dimethyl silicone oil at 25°C is 350 mm 2 / s. Dimethyl silicone oil has good fluidity, is easy to process, and is easy to be uniformly dispersed and distributed in the material.

[0084] The present invention also proposes a preparation method of a ceramifiable silicone rubber insulating material, and the preparation method includes:

[0085] Step S100, adding 100 parts of silicone rubber into a two-roll open mill, and carrying out internal mixing according to the front and rear roll speed ratio of 1:1.22 of the two-roll open mill to soften it;

[0086] Step S200, sequentially adding 5 parts to 20 parts of stabilizer, 0.5 part to 1 part of surface treatment agent, 30 parts to 40 parts of flame retardant, 45 parts to 50 parts of ceramifying filler, 25 parts to 30 parts of reinforcing agent, 5 parts to 8 parts of flux, 0.5 part to 2 parts of vulcanizing agent into the two-roll open mill, and continuously carrying out internal mixing at a temperature of 35°C to 45°C for 10 min to 30 min.

[0087] The following further describes clearly and completely the technical features in the technical solutions provided by the present invention in combination with specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0088] For those not specifying specific techniques or conditions in the embodiments, they shall be carried out according to the techniques or conditions described in the literature in this field or according to the product specifications. For reagents or instruments not indicating the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0089] Embodiment 1

[0090] 100 parts of silicone rubber;

[0091] 0.5 part of vulcanizing agent;

[0092] 25 parts of reinforcing agent;

[0093] 5 parts of flux;

[0094] 45 parts of ceramizing filler;

[0095] 30 parts of flame retardant;

[0096] 0.5 part of surface treatment agent;

[0097] 5 parts of stabilizer.

[0098] Among them, the silicone rubber is methyl vinyl silicone raw rubber, and the vinyl content in the methyl vinyl silicone raw rubber is 0.03%; the vulcanizing agent is 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane; the reinforcing agent is fumed silica; the flux is low-melting glass powder, the particle size of the low-melting glass powder is selected as 800 mesh, and the softening point of the low-melting glass powder is 480 °C; the ceramizing filler is selected as 18 parts of mica, 3 parts of glass microspheres, 10 parts of tetragonal zirconia powder and 14 parts of halloysite by weight; the flame retardant is magnesium hydroxide; the surface treatment agent is vinyltrimethylsilane; the stabilizer is dimethyl silicone oil, and the viscosity of the dimethyl silicone oil at 25 °C is 350 mm 2 / s.

[0099] Embodiment 2

[0100] 100 parts of silicone rubber;

[0101] 1 part of vulcanizing agent;

[0102] 27 parts of reinforcing agent;

[0103] 6 parts of flux;

[0104] 47 parts of ceramizing filler;

[0105] 35 parts of flame retardant;

[0106] 0.7 part of surface treatment agent;

[0107] 12 parts of stabilizer.

[0108] Among them, the silicone rubber is methyl vinyl silicone raw rubber, and the vinyl content in the methyl vinyl silicone raw rubber is 0.035%; the vulcanizing agent is 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane; the reinforcing agent is fumed silica; the flux is low-melting glass powder, the particle size of the low-melting glass powder is selected as 900 mesh, and the softening point of the low-melting glass powder is 480 °C; the ceramizing filler is selected by weight as 20 parts of mica, 5 parts of glass microspheres, 15 parts of tetragonal zirconia powder and 9 parts of halloysite; the flame retardant is magnesium hydroxide; the surface treatment agent is vinyltrimethylsilane; the stabilizer is dimethyl silicone oil, and the viscosity of the dimethyl silicone oil at 25 °C is 350 mm 2 / s.

[0109] Example 3

[0110] 100 parts of silicone rubber;

[0111] 2 parts of vulcanizing agent;

[0112] 30 parts of reinforcing agent;

[0113] 8 parts of flux;

[0114] 50 parts of ceramizing filler;

[0115] 40 parts of flame retardant;

[0116] 1 part of surface treatment agent;

[0117] 20 parts of stabilizer.

[0118] Among them, the silicone rubber is methyl vinyl silicone raw rubber, and the vinyl content in the methyl vinyl silicone raw rubber is 0.04%; the vulcanizing agent is 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane; the reinforcing agent is fumed silica; the flux is low-melting glass powder, the particle size of the low-melting glass powder is selected as 1000 mesh, and the softening point of the low-melting glass powder is 480 °C; the ceramizing filler is selected by weight as 22 parts of mica, 7 parts of glass microspheres, 20 parts of tetragonal zirconia powder and 1 part of halloysite; the flame retardant is magnesium hydroxide; the surface treatment agent is vinyltrimethylsilane; the stabilizer is dimethyl silicone oil, and the viscosity of the dimethyl silicone oil at 25 °C is 350 mm 2 / s.

[0119] Perform performance tests on Example 1, Example 2 and Example 3. The test methods include:

[0120] The mechanical property test was carried out in accordance with the standard of GB / T 2951.11-2008;

[0121] The air heat aging test was carried out in accordance with the standard of GB / T 2951.12-2008, and the test conditions were as follows: in an air box and aged at 200 °C for 168 hours;

[0122] The three-point bending strength was determined according to GB / T 9341-2008, and the impact strength was determined according to GB / T 1043.1-2008.

[0123] The burning test was carried out at a flame temperature of 950 °C.

[0124] The performance test results are referred to Table 1.

[0125] Table 1

[0126]

[0127] The present invention also provides a fire-resistant cable 100, which includes a sheath 10 and a plurality of cable cores 20. The sheath 10 is sleeved outside the plurality of cable cores 20, and an insulating layer 30 is wrapped around each cable core 20. The material of the insulating layer 30 is the above-mentioned ceramifiable silicone rubber insulating material. Referring to the above-mentioned embodiments, since the fire-resistant cable 100 adopts all the technical solutions of the above-mentioned all embodiments,

[0128] Therefore, it has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, and will not be elaborated one by one here.

[0129] In an embodiment of the present invention, the cable core 20 in the fire-resistant cable 100 is formed by stranding at least 19 conductive cores 21. The conductive core 21 is a tinned copper single wire, the diameter of the tinned copper single wire is less than or equal to 2.62 mm, and the elongation rate of the tinned copper single wire is 23% - 27%.

[0130] Specifically, the cable core 20 is formed by stranding at least 19 conductive cores 21. This design of stranding multiple wires makes the cable core 20 have good flexibility and can adapt to the bending and movement of the fire-resistant cable 100 during installation and use. And the stranding structure of multiple conductive cores 21 provides higher mechanical strength, so that the fire-resistant cable 100 can withstand greater tensile force and mechanical stress, and reduce the damage caused by external forces during use.

[0131] Furthermore, the conductive core 21 is made of tinned copper single wire. The tin plating layer can improve the electrical conductivity of the copper single wire, reduce the contact resistance, and ensure the efficiency and stability of current transmission. Moreover, it can protect the copper single wire from oxidation in humid or corrosive environments and extend the service life of the cable. The diameter of the tinned copper single wire is less than or equal to 2.62 mm. This relatively small diameter helps to improve the flexibility and filling density of the cable core 20, making the stranded cable core 20 more compact and uniform. The elongation rate of the tinned copper single wire is 23% - 27%. The elongation rate within this range can ensure that the single wire has good processability during the stranding process and can withstand a certain tensile stress during use, avoiding wire breakage caused by excessive elongation.

[0132] In an embodiment of the present invention, the cable core 20 includes a first cable core layer and a second cable core layer. The second cable core layer is wrapped around the outer periphery of the first cable core layer. The first cable core layer is formed by stranding 7 conductive cores 21 in a 1 + 6 structure. The stranding pitch of the first cable core layer is 113 mm - 156 mm. The second cable core layer is formed by stranding 12 conductive cores 21. The stranding pitch of the second cable core layer is 138 mm - 163 mm.

[0133] Specifically, the cable core 20 includes a first cable core layer and a second cable core layer. This multi-layer stranding structure can significantly improve the flexibility and mechanical strength of the cable core 20. The first cable core layer is formed by stranding 7 conductive cores 21 in a 1 + 6 structure. This structure enables the first cable core layer to have good flexibility and mechanical strength, and can adapt to the bending and movement of the cable during installation and use. The second cable core layer is formed by stranding 12 conductive cores 21 and is wrapped around the outer periphery of the first cable core layer, further enhancing the overall mechanical strength and flexibility of the cable core 20. This multi-layer stranding structure makes the cable core 20 more stable when bearing tensile force and mechanical stress, reducing the risk of damage caused by external forces.

[0134] Furthermore, the stranding pitch of the first cable core layer is 113 mm - 156 mm. This pitch range can ensure that the conductive cores 21 are closely arranged during the stranding process, improving the filling density and mechanical strength of the cable core 20. At the same time, an appropriate pitch can ensure the flexibility and recovery ability of the cable core 20 when bent. The stranding pitch of the second cable core layer is 138 mm - 163 mm. This pitch range further optimizes the flexibility and mechanical properties of the cable core 20. The longer pitch makes the second cable core layer more uniform when wrapping the first cable core layer, improving the overall tightness and stability.

[0135] In an embodiment of the present invention, the thickness of the insulating layer 30 is 1.6 mm to 1.8 mm. The thickness of the insulating layer 30 within the range of 1.6 mm to 1.8 mm can effectively improve the insulation strength of the fire-resistant cable 100 and ensure the safe operation of the fire-resistant cable 100 in a high-voltage environment. This thickness range can effectively prevent current leakage and breakdown, improving the reliability and safety of the cable.

[0136] In an embodiment of the present invention, a halogen-free low-smoke flame-retardant glass fiber filling rope 50 is further provided within the sheath 10, and the halogen-free low-smoke flame-retardant glass fiber filling rope 50 is located between the cable core 20 and the sheath 10.

[0137] Specifically, the halogen-free low-smoke flame-retardant glass fiber filling rope 50 has excellent flame-retardant properties, can effectively prevent the spread of fire within the cable, and improve the fire resistance of the fire-resistant cable 100. And this filling rope has a certain mechanical strength and toughness, can withstand the stress and deformation generated during the installation and use of the fire-resistant cable 100, enhancing the overall tensile performance of the fire-resistant cable 100. It can also effectively fill the gap between the cable core 20 and the sheath 10, making the structure of the fire-resistant cable 100 more compact and stable, improving the roundness of the fire-resistant cable 100, and preventing the fire-resistant cable 100 from being damaged due to internal looseness during use.

[0138] In an embodiment of the present invention, the wrapping layer 40 is wrapped around the outer periphery of the halogen-free low-smoke flame-retardant glass fiber filling rope 50 and the insulating layers 30 of the plurality of cable cores 20.

[0139] Specifically, the wrapping layer 40 can keep the fire-resistant cable 100 in a round shape, prevent the cable core 20 from loosening or shifting within the sheath 10, and ensure the structural stability and appearance quality of the fire-resistant cable 100. And the wrapping layer 40 can also make the stress distribution of the fire-resistant cable 100 more uniform when stressed, avoiding damage to the insulating layer 30 or the sheath 10 caused by local stress concentration, and extending the service life of the cable.

[0140] In an embodiment of the present invention, the sheath 10 layer is a silicone rubber sheath 10 layer, and the thickness of the silicone rubber sheath 10 layer is 2.2 mm to 2.4 mm. The thickness of the silicone rubber sheath 10 layer within the range of 2.2 mm to 2.4 mm can improve the tensile strength of the fire-resistant cable 100, enabling it to withstand greater tensile forces during installation and use, reducing the risk of damage caused by external forces. At the same time, the relatively thick sheath 10 layer can also improve the abrasion resistance of the cable and protect the internal structure.

[0141] The above description is only an exemplary embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformation made under the technical concept of the present invention by using the content of the specification and drawings of the present invention, or directly / indirectly applied in other related technical fields, is included within the patent protection scope of the present invention.

Claims

1. A ceramicizable silicone rubber insulating material, characterized in that: The ceramicizable silicone rubber insulating material comprises, by weight: Silicone rubber 100 parts; 0.5 to 2 parts of vulcanizing agent; 25 to 30 parts of reinforcing agent; 5 to 8 parts of flux; 45 to 50 parts of porcelain filler; 30 to 40 parts of flame retardant; Surface treatment agent 0.5 to 1 part; 5 to 20 parts of stabilizer.

2. The ceramicizable silicone rubber insulating material according to claim 1, characterized in that: The silicone rubber is methyl vinyl silicone rubber, and the vinyl content of the methyl vinyl silicone rubber is 0.03% to 0.04%.

3. The ceramicizable silicone rubber insulating material according to claim 1, characterized in that: The vulcanizing agent is 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane.

4. The ceramicizable silicone rubber insulating material according to claim 1, characterized in that: The reinforcing agent is fumed silica.

5. The ceramicizable silicone rubber insulating material according to claim 1, characterized in that: The flux is low-melting-point glass powder, the softening point of the low-melting-point glass powder is 480° C., and the particle size of the low-melting-point glass powder is 800-1000 meshes.

6. The ceramicizable silicone rubber insulating material according to any one of claims 1 to 5, characterized in that: The ceramic filler comprises, by weight: Mica 18 to 22 parts; 3 to 7 parts of glass beads; 10 to 20 parts of tetragonal zirconium oxide powder; Halloysite 5 to 10 parts.

7. The ceramicizable silicone rubber insulating material according to any one of claims 1 to 5, characterized in that: The flame retardant is magnesium hydroxide; and / or; The surface treatment agent is vinyltrimethylsilane.

8. The ceramicizable silicone rubber insulating material according to any one of claims 1 to 5, characterized in that: The stabilizer is dimethyl silicone oil, and the viscosity of the dimethyl silicone oil at 25°C is 350 mm 2 / s.

9. A method for preparing a ceramic silicone rubber insulating material, characterized in that: The preparation method comprises: 100 parts of silicone rubber were added to a two-roll mill, and the two-roll mill was mixed at a front and rear roll speed ratio of 1:1.22 to soften the silicone rubber; 5 to 20 parts of a stabilizer, 0.5 to 1 part of a surface treatment agent, 30 to 40 parts of a flame retardant, 45 to 50 parts of a ceramic filler, 25 to 30 parts of a reinforcing agent, 5 to 8 parts of a flux, and 0.5 to 2 parts of a vulcanizing agent are sequentially added to the double-roll mill, and the mixing is continued at a temperature of 35° C. to 45° C. for 10 to 30 minutes.

10. A fire-resistant cable, characterized in that: The fire-resistant cable comprises a sheath and a plurality of cable cores, wherein the sheath is sleeved on the outside of the plurality of cable cores, and each of the cable cores is wrapped with an insulating layer, and the material of the insulating layer is the ceramicizable silicone rubber insulating material as described in any one of claims 1 to 8.

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