150 degree c irradiation crosslinking low smoke halogen-free flame-retardant cable material and its preparation method

Abstract

This invention provides a 150℃ irradiated crosslinked low-smoke halogen-free flame-retardant cable material and its preparation method, relating to the field of cable material technology. The cable material of this invention, by weight, comprises the following raw materials: 50-60 parts high-density polyethylene, 10-15 parts maleic anhydride and vinyl silane double-grafted high-density polyethylene, 30-40 parts polyolefin elastomer, 120-140 parts silane-modified magnesium hydroxide, 5-10 parts nano-sodium antimonate, 5-10 parts zinc borate, 2.5-4 parts loaded composite antioxidant microparticles, 3-5 parts hydroxyl-terminated ultra-high molecular weight silicone powder, 1-2 parts sensitizing crosslinking agent, and 0.5-1 parts auxiliary crosslinking agent. The wires and cables made from this cable material achieve a 150℃ temperature resistance rating while also possessing excellent flame-retardant properties, low smoke characteristics, anti-emission properties, and long-term thermo-oxidative aging stability.

Description

Technical Field

[0001] This invention relates to the field of cable material technology, and in particular to a 150°C irradiated cross-linked low-smoke halogen-free flame-retardant cable material and its preparation method. Background Technology

[0002] With the rapid development of electronics, new energy vehicles, communication equipment, and rail transportation, cables are widely used as internal connection wires in equipment. Especially in confined spaces with limited heat dissipation, electronic wires often operate at high temperatures, making 150℃ heat-resistant cable materials conforming to UL758 / 1581 standards a critical material urgently needed in the market. These cables typically require excellent flame retardancy, long-term thermo-oxidative stability, good physical and mechanical strength, and environmental friendliness to ensure safety and reliability under complex operating conditions.

[0003] A domestic patent discloses a 135℃ thermoplastic low-smoke halogen-free flame-retardant material for cables (application publication number CN 106397991 A). This material does not produce large amounts of dense smoke and hydrogen halide gas when burning, and can be used at 135℃ for extended periods, exhibiting high safety. However, during long-term use, the antioxidants in this material tend to migrate and leach onto the cable surface, affecting the cable's appearance and performance stability. Furthermore, its temperature resistance rating is only 135℃, which cannot meet the requirement for long-term use at 150℃.

[0004] Therefore, there is an urgent need to develop a cable material that can simultaneously achieve low-smoke, non-toxic combustion, inhibit high-temperature aging, and meet the 150℃ temperature resistance requirement. Summary of the Invention

[0005] The purpose of this invention is to provide a 150℃ irradiated crosslinked low-smoke halogen-free flame-retardant cable material and its preparation method, so as to solve the technical problem that existing cable materials are difficult to achieve both low-smoke and non-toxic combustion and inhibit high-temperature precipitation aging.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: The first aspect of this invention provides a 150°C irradiated crosslinked low-smoke halogen-free flame-retardant cable material, which, by weight, comprises the following raw materials: 50-60 parts of high-density polyethylene, 10-15 parts of maleic anhydride and vinyl silane double-grafted high-density polyethylene, 30-40 parts of polyolefin elastomer, 120-140 parts of silane-modified magnesium hydroxide, 5-10 parts of nano-sodium antimonate, 5-10 parts of zinc borate, 2.5-4 parts of loaded composite antioxidant microparticles, 3-5 parts of hydroxyl-terminated ultra-high molecular weight silicone powder, 1-2 parts of sensitizing crosslinking agent, and 0.5-1 parts of auxiliary crosslinking agent; The supported composite antioxidant microparticles, by weight, include the following raw materials: 2.4-2.8 parts mesoporous silica, 1-1.4 parts active antioxidant component, 0.05-0.12 parts silane coupling agent, and 0.02-0.08 parts hydroxyl-terminated silicone oil.

[0007] Optionally, the mesoporous silica has a pore size of 2nm-10nm and a specific surface area of ​​600m². 2 / g-800m 2 / g.

[0008] Optionally, in the maleic anhydride and vinyl silane double-grafted high-density polyethylene, the grafting rate of maleic anhydride is 0.5%-1.2%, and the grafting rate of vinyl silane is 0.2%-0.8%.

[0009] Optionally, the viscosity-average molecular weight of the terminal hydroxyl ultra-high molecular weight silicone powder is 800,000 to 1,200,000.

[0010] Optionally, the active antioxidant component is a composition of antioxidant 1010 and antioxidant DSTP, and the weight ratio of antioxidant 1010 to antioxidant DSTP is (1.5-2.5):1.

[0011] Optionally, the silane coupling agent is selected from any one of γ-methacryloxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, or γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

[0012] Optionally, the sensitizing crosslinking agent is triallyl isocyanurate, and the auxiliary crosslinking agent is trimethylolpropane triacrylate.

[0013] Optionally, the preparation method of the supported composite antioxidant microparticles includes the following steps: A1. Under an inert atmosphere, the active antioxidant component is heated to a molten state, and the mesoporous silica is added to it. While stirring, the vacuum degree is adjusted to -0.09MPa to -0.1MPa and maintained for 1.5h to 3h to obtain the first composite material. A2. Add the silane coupling agent to the first composite material obtained in step A1, heat to 70℃-85℃ and react for 45min-60min. After the reaction is completed, cool, dry and pulverize to obtain the second composite material. A3. The hydroxyl-terminated silicone oil is sprayed onto the surface of the second composite material obtained in step A2 by atomization spraying, and after curing, the loaded composite antioxidant microparticles are obtained.

[0014] Optionally, the method for preparing the maleic anhydride and vinylsilane double-grafted high-density polyethylene includes the following steps: B1. A premix is ​​prepared by mixing high-density polyethylene particles, maleic anhydride, vinyl silane, initiator, and hindered phenolic antioxidant. B2. The premix obtained in step B1 is added to a twin-screw extruder and melt-extruded at a temperature of 170℃-210℃. After being cooled by water and dried, the maleic anhydride and vinyl silane double-grafted high-density polyethylene is obtained.

[0015] A second aspect of the present invention provides a method for preparing the above-mentioned 150°C irradiated crosslinked low-smoke halogen-free flame-retardant cable material, comprising the following steps: S1. High-density polyethylene, maleic anhydride and vinyl silane double-grafted high-density polyethylene, polyolefin elastomer, supported composite antioxidant microparticles, hydroxyl-terminated ultra-high molecular weight silicone powder and part of sensitizing crosslinking agent are placed in a first high-speed mixer to prepare a first premix. S2. The first premix obtained in step S1, silane-modified magnesium hydroxide, nano-sodium antimonate and zinc borate are placed in a second high-speed mixer and heated to 140℃-160℃ for intensive mixing to prepare the second premix. S3. The second premix obtained in step S2 is placed in a two-stage extruder. In the first-stage twin-screw mixing section, the remaining amount of the sensitizing crosslinking agent and auxiliary crosslinking agent are injected online through side feeding for dynamic homogenization. Then, it is extruded and pelletized at 155℃-165℃ in the second-stage single-screw section to obtain 150℃ irradiated crosslinked low-smoke halogen-free flame-retardant cable material.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. The cable material of this invention is halogen-free and uses silane-modified magnesium hydroxide as the flame-retardant matrix, combined with nano-sodium antimonate and zinc borate to form a multi-component synergistic flame-retardant system. During combustion, the silane-modified magnesium hydroxide decomposes upon heating, releasing moisture and absorbing heat, while nano-sodium antimonate and zinc borate induce in-situ charring of the matrix at high temperatures, forming a continuous and dense ceramicized carbon layer. This carbon layer not only blocks the inward transfer of oxygen and heat but also forms a mechanical and physical barrier on the surface of the irradiated cross-linked cable insulation melt, effectively suppressing smoke release and the escape of harmful gases, achieving low-smoke and non-toxic combustion.

[0017] 2. The vinyl silane functional groups in double-grafted high-density polyethylene contain crosslinkable double bonds, enabling them to participate in crosslinking reactions under irradiation conditions and form a stable three-dimensional network structure with the matrix. This improves the thermal stability and resistance to thermo-oxidative aging of the irradiated crosslinked cable insulation layer at 150°C. Furthermore, the loaded composite antioxidant microparticles achieve triple slow-release and migration inhibition of active antioxidant components through pore confinement of mesoporous silica, pore modification of silane coupling agents, and surface coating with hydroxyl-terminated silicone oil. The synergistic effect of these two factors suppresses precipitation and thermo-oxidative aging phenomena in the irradiated crosslinked cable insulation layer under high-temperature service conditions.

[0018] 3. The synergistic optimization of the proportions of each component in the cable material and the internal structure of the load-bearing composite antioxidant microparticles further enhances the synergistic improvement of flame retardancy, smoke suppression and high-temperature anti-deposition performance, ensuring that the cable insulation layer after irradiation cross-linking can still maintain stable flame retardant performance and electrical reliability under 150℃ thermal aging conditions.

[0019] The above and other objects, advantages and features of the present invention will become more apparent to those skilled in the art from the following detailed description of specific embodiments of the invention. Detailed Implementation

[0020] The terms “comprising” and “having”, and any variations thereof, used in this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus.

[0021] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0022] A 150℃ irradiated crosslinked low-smoke halogen-free flame-retardant cable material, by weight, comprises the following raw materials: 50-60 parts high-density polyethylene, 10-15 parts maleic anhydride and vinyl silane double-grafted high-density polyethylene, 30-40 parts polyolefin elastomer, 120-140 parts silane-modified magnesium hydroxide, 5-10 parts nano-sodium antimonate, 5-10 parts zinc borate, 2.5-4 parts supported composite antioxidant microparticles, 3-5 parts hydroxyl-terminated ultra-high molecular weight silicone powder, 1-2 parts sensitizing crosslinking agent, and 0.5-1 parts auxiliary crosslinking agent; wherein the supported composite antioxidant microparticles, by weight, comprise the following raw materials: 2.4-2.8 parts mesoporous silica, 1-1.4 parts active antioxidant component, 0.05-0.12 parts silane coupling agent, and 0.02-0.08 parts hydroxyl-terminated silicone oil.

[0023] In this embodiment, the cable material is halogen-free and uses silane-modified magnesium hydroxide as the flame-retardant matrix, combined with nano-sodium antimonate and zinc borate to form a multi-component synergistic flame-retardant system. During combustion, the silane-modified magnesium hydroxide decomposes upon heating, releasing moisture and absorbing heat, while nano-sodium antimonate and zinc borate induce in-situ charring of the matrix at high temperatures, forming a continuous and dense ceramicized carbon layer. This carbon layer not only blocks the inward transfer of oxygen and heat but also forms a mechanical and physical barrier on the surface of the radiated cross-linked cable insulation melt, effectively suppressing smoke release and the escape of harmful gases, achieving low-smoke and non-toxic combustion. The vinyl silane functional groups in the double-grafted high-density polyethylene contain cross-linkable double bonds, which can participate in the cross-linking reaction under irradiation conditions, forming a stable three-dimensional network structure with the matrix, improving the thermal stability and resistance to thermo-oxidative aging of the radiated cross-linked cable insulation layer at 150°C. Furthermore, the loaded composite antioxidant microparticles achieve triple slow-release and migration inhibition of active antioxidant components through pore confinement of mesoporous silica, pore modification of silane coupling agents, and surface coating of hydroxyl-terminated silicone oil. The synergistic effect of these two factors suppresses precipitation and thermo-oxidative aging in the irradiated cross-linked cable insulation layer under high-temperature service conditions. The synergistic optimization of the component ratios in the cable material and the internal structure of the loaded composite antioxidant microparticles further enhances the synergistic improvement of flame retardant and smoke-suppressing properties and high-temperature anti-precipitation performance, ensuring that the irradiated cross-linked insulation layer maintains stable flame retardant performance and electrical reliability even under 150℃ thermal aging conditions.

[0024] In this embodiment, the active antioxidant component is loaded into the pores of the mesoporous silica, the slow-release control layer formed by the silane coupling agent is used to reduce the pore diameter of the mesoporous silica, and the barrier film formed by the hydroxyl-terminated silicone oil is coated on the surface of the mesoporous silica.

[0025] During the preparation of cable materials, most of the active antioxidant components are stably locked within the nanopores of mesoporous silica. At this point, only trace amounts of active antioxidant components escape from the barrier membrane through permeation. This is sufficient to complement the polar interface protection of double-grafted high-density polyethylene, providing necessary thermal protection during low-temperature extrusion and ensuring that the polymer molecular chains do not undergo thermo-oxidative degradation. When the cable insulation layer, made by irradiation crosslinking of the cable material, is placed in an aging environment at 150°C, the concentration gradient of free radicals generated by matrix oxidation triggers the slow-release mechanism of the active antioxidant components, causing them to be slowly released from the mesoporous silica pores into the matrix. This ensures long-term high-temperature thermo-oxidative stability and avoids the migration, precipitation, and blooming caused by excessive free release of active antioxidant components in conventional technologies, thus keeping the surface of the cable insulation layer smooth and stable for a long time.

[0026] In this embodiment, the high proportion of 120-140 parts of silane-modified magnesium hydroxide filling is the basis for achieving low-smoke, halogen-free flame retardancy. However, due to the large polarity difference between inorganic particles and the non-polar polyolefin matrix, it easily leads to material embrittlement and a sharp reduction in strength. Maleic anhydride functional groups form strong chemical bonds with the hydroxyl groups on the surfaces of magnesium hydroxide, nano-sodium antimonate, and zinc borate. Simultaneously, during the preparation process, vinyl silane functional groups further enhance the interfacial adhesion between the inorganic filler and the grafted material through hydrolysis condensation or reaction with the silanol groups on the surface of inorganic particles, and can participate in subsequent irradiation crosslinking reactions. The long-chain polyethylene segments of the double-grafted high-density polyethylene physically entangle with the high-density polyethylene and polyolefin elastomer matrix, constructing a very strong polar interfacial coupling effect. The above technical effects improve the dispersion uniformity of inorganic fillers during processing, achieving nanoscale dispersion and effectively eliminating stress concentration caused by filler agglomeration. Thus, while maintaining a high flame retardant rating, it ensures that the cable insulation layer made by irradiation cross-linking of cable material has excellent tensile strength and elongation at break, meeting the mechanical reliability requirements of high-temperature service environment of 150℃.

[0027] In this embodiment, the hydroxyl-terminated ultra-high molecular weight silicone powder has extremely low surface energy and still exhibits excellent processing lubricity and high-speed extrusion performance in a high inorganic filler system. It reduces extrusion torque and improves processing fluidity, enhances the smoothness and gloss of the extruded surface of the cable material, and effectively improves the extrusion speed and production speed.

[0028] In this embodiment, a dense hydrophobic barrier is constructed on the surface of the inorganic filler by modifying magnesium hydroxide with silane and combining it with the strong interfacial adhesion of double-grafted high-density polyethylene. This hydrophobic interface effectively prevents moisture in the air or in the service environment from penetrating into the cable insulation layer, avoiding the increased polarity caused by the moisture absorption of inorganic particles such as magnesium hydroxide. Therefore, the cable insulation layer can maintain extremely low dielectric loss and high volume resistivity throughout long-term service, reducing the risk of leakage current and thus improving the operational safety and electrical service life of the cable in harsh environments with high temperature and high humidity.

[0029] In this embodiment, the average particle size of nano-sodium antimonate is set to 30nm-80nm to improve its dispersion uniformity and interfacial interaction efficiency in the high-filling system, reduce local defects and stress concentration caused by agglomeration, thereby improving the structural consistency and processing stability of the cable material. Simultaneously, it helps to enhance the synergistic effect of nano-sodium antimonate in the flame-retardant system, improve the flame-retardant response rate and the ability to inhibit combustion chain reactions, thereby further improving the overall flame-retardant performance and long-term thermal stability of the cable insulation layer. The average particle size of nano-sodium antimonate can be, for example, 30nm, 50nm, 70nm, 80nm, or any other value within the 30nm-80nm range.

[0030] In another embodiment, the mesoporous silica has a pore size of 2nm-10nm and a specific surface area of ​​600m². 2 / g-800m 2 / g. This parameter range enables mesoporous silica to possess high effective loading capacity and excellent dispersion stability, effectively improving the loading efficiency of active antioxidant components. Furthermore, this parameter ensures high loading capacity while enhancing the cable material's adaptability to external environmental effects, strengthening the resistance of the irradiated cross-linked cable insulation layer to external environmental factors, and contributing to improved long-term heat and oxygen aging resistance and operational reliability.

[0031] The pore size of mesoporous silica can be, for example, 2 nm, 5 nm, 8 nm, 10 nm, or any other value between 2 nm and 10 nm, and the specific surface area can be, for example, 600 m². 2 / g、650m 2 / g、700m 2 / g、800m 2 / g, or 600m 2 / g-800m 2 Any other value in / g.

[0032] In a further embodiment, in the maleic anhydride and vinyl silane double-grafted high-density polyethylene, the grafting rate of maleic anhydride is 0.5%-1.2%, and the grafting rate of vinyl silane is 0.2%-0.8%. This allows the double-grafted high-density polyethylene to maintain the mechanical and processing properties of the main polyolefin while possessing suitable polarity control and cross-linking reactivity. This improves its interfacial compatibility and dispersion uniformity with the highly filled inorganic flame-retardant system, reducing the probability of filler agglomeration and interfacial defects. Furthermore, the synergistic effect of the two grafting groups enables the cable material of this application to possess good melt stability and flow uniformity during processing, and the cable insulation layer exhibits excellent structural stability and heat aging resistance during long-term service.

[0033] The grafting rate of maleic anhydride is 0.5%, 0.8%, or 1.2%, or any other value between 0.5% and 1.2%. The grafting rate of vinylsilane is 0.2%, 0.6%, or 0.8%, or any other value between 0.2% and 0.8%.

[0034] In a further embodiment, the viscosity-average molecular weight of the hydroxyl-terminated ultra-high molecular weight silicone powder is 800,000-1,200,000. This allows it to possess sufficient molecular chain length to provide stable and long-lasting lubrication and interface regulation during cable material processing, while also maintaining good dispersibility and migration adaptability. This results in a uniform and stable lubrication zone during melt mixing and extrusion molding, reducing frictional resistance and shear stress fluctuations within the system. Simultaneously, this molecular weight range helps improve its interfacial compatibility in highly filled inorganic systems, enhances melt flow uniformity and processing stability, reduces surface flow defects, and enables the cable material to maintain stable processing performance and excellent product surface quality under high-speed extrusion conditions. Furthermore, it enhances the structural stability and overall reliability of the cable insulation layer during long-term service. The viscosity-average molecular weight of the hydroxyl-terminated ultra-high molecular weight silicone powder can be, for example, 800,000, 900,000, 1,000,000, or 1,200,000, or any other value within the range of 800,000-1,200,000.

[0035] In a further embodiment, the active antioxidant component is a composition of antioxidant 1010 and antioxidant DSTP, and the weight ratio of antioxidant 1010 to antioxidant DSTP is (1.5-2.5):1. By optimizing the ratio of the two antioxidants, the heat and oxygen aging resistance and long-term operational reliability of the cable insulation layer are improved. The weight ratio of antioxidant 1010 to antioxidant DSTP can be, for example, 1.5:1, 2:1, 2.5:1, or any other value among (1.5-2.5):1.

[0036] In a further embodiment, the sensitizing crosslinking agent is triallyl isocyanurate, and the auxiliary crosslinking agent is trimethylolpropane triacrylate, enabling the cable material to form a multifunctional synergistic crosslinking structure during the irradiation crosslinking process. The synergistic effect of the two can improve the crosslinking efficiency and uniformity of the cable material under irradiation conditions, thereby improving the heat deformation resistance, mechanical strength, and long-term thermo-oxidative aging stability of the cable insulation layer.

[0037] In a further embodiment, the method for preparing the supported composite antioxidant microparticles includes the following steps: A1. Under an inert atmosphere, the active antioxidant component is heated to a molten state, and mesoporous silica is added to it. While stirring, the vacuum degree is adjusted to -0.09MPa to -0.1MPa and maintained for 1.5h to 3h to obtain the first composite material. A2. Add the silane coupling agent to the first composite material obtained in step A1, heat to 70℃-85℃ and react for 45min-60min. After the reaction is completed, cool, dry and pulverize to obtain the second composite material. A3. Hydroxyl-terminated silicone oil is sprayed onto the surface of the second composite material obtained in step A2 through atomization spraying, and after curing, loaded composite antioxidant microparticles are obtained.

[0038] In step A1, the active antioxidant component is heated to a molten state under an inert atmosphere to give it good flow and penetration capabilities. At the same time, mesoporous silica is added and the mixture is treated in a vacuum environment of -0.09MPa to -0.1MPa for 1.5h to 3h under stirring conditions. This allows the molten antioxidant component to fully enter the pores of the mesoporous silica under the pressure difference, thereby achieving efficient loading and confined fixation of the active antioxidant component and forming the first composite material.

[0039] In step A2, the silane coupling agent is added dropwise to the first composite material obtained in step A1, and reacted at 70℃-85℃ for 45min-60min, so that the silane coupling agent undergoes a grafting and curing reaction on the surface of mesoporous silica and the pore area, thereby modifying the structure and controlling the size of the pore entrance, and thus forming a second composite material with slow-release control capability.

[0040] In step A3, hydroxyl-terminated silicone oil is sprayed onto the surface of the second composite material using an atomized spray method to form a barrier film on the surface of the second composite material.

[0041] In a further embodiment, the method for preparing maleic anhydride and vinylsilane double-grafted high-density polyethylene includes the following steps: B1. A premix is ​​prepared by mixing high-density polyethylene particles, maleic anhydride, vinyl silane, initiator, and hindered phenolic antioxidant. B2. The premix obtained in step B1 is added to a twin-screw extruder and melt-extruded at a temperature of 170℃-210℃. After being cooled by water and dried, maleic anhydride and vinyl silane double-grafted high-density polyethylene is obtained.

[0042] In step B2, the premix is ​​melt-extruded in a twin-screw extruder at 170℃-210℃. During this process, high-density polyethylene generates free radicals under the action of an initiator, and maleic anhydride and vinyl silane undergo a grafting reaction on the polyethylene molecular chain. The strong shearing action of the twin-screw extruder improves the uniformity and efficiency of the grafting reaction and reduces unreacted monomer residues. After water cooling and drying, the extrudate yields maleic anhydride and vinyl silane double-grafted high-density polyethylene.

[0043] Specifically, the preparation method of 150℃ irradiated cross-linked low-smoke halogen-free flame-retardant cable material includes the following steps: S1. High-density polyethylene, maleic anhydride and vinyl silane double-grafted high-density polyethylene, polyolefin elastomer, supported composite antioxidant microparticles, hydroxyl-terminated ultra-high molecular weight silicone powder and part of sensitizing crosslinking agent are placed in a first high-speed mixer to prepare a first premix. S2. The first premix obtained in step S1, silane-modified magnesium hydroxide, nano-sodium antimonate and zinc borate are placed in a second high-speed mixer and heated to 140℃-160℃ for intensive mixing to prepare the second premix. S3. The second premix obtained in step S2 is placed in a two-stage extruder. In the first-stage twin-screw mixing section, the remaining sensitizing crosslinking agent and auxiliary crosslinking agent are injected online through side feeding for dynamic homogenization. In the second-stage single-screw section, it is extruded and pelletized at 155℃-165℃ to obtain 150℃ irradiated crosslinked low-smoke halogen-free flame-retardant cable material.

[0044] In step S1, the rotation speed of the first high-speed mixer is 800 rpm-1000 rpm for 5 min-10 min, so that the components can be initially uniformly dispersed and mixed in a solid or semi-molten state, improving the interfacial contact in the subsequent melt mixing stage. A portion of the sensitizing crosslinking agent is added in this step to pre-disperse it uniformly in the polymer matrix, avoiding problems such as excessively high local concentrations or uneven dispersion when added later.

[0045] In step S2, the rotation speed of the second high-speed mixer is 600rpm-800rpm, and the mixing time is 10min-20min, so that the inorganic filler and the polymer matrix are fully and uniformly mixed, and the filler is dispersed at the nanoscale to prepare the second premix.

[0046] In step S3, the remaining sensitizing crosslinking agent and auxiliary crosslinking agent are dynamically homogenized by side-feeding online injection in the first-stage twin-screw mixing section, achieving efficient and uniform dispersion of the crosslinking agent and low-temperature stable processing. Simultaneously, the second-stage single-screw section performs extrusion at 155℃-165℃ to prevent scorching during processing, ensuring smooth pelleting and good pellet appearance, thus improving the stability and yield of cable material processing.

[0047] In the following preparation examples, embodiments, and comparative examples, high-density polyethylene (HDPE) was commercially available (purchased from Henan Fengbai Industrial Co., Ltd.), polyolefin elastomer was commercially available (purchased from Dow Chemical Company, model Engage 8150), nano sodium antimonate was commercially available (purchased from Changsha Yexing Antimony Industry Co., Ltd., average particle size 50nm), zinc borate was commercially available (purchased from Shandong Wuwei Flame Retardant Technology Co., Ltd., average particle size 1μm-3μm), sensitizing crosslinking agent was commercially available triallyl isocyanurate (TAIC, purchased from Shanghai Tuojing New Material Technology Co., Ltd., purity ≥98%), and auxiliary crosslinking agent was commercially available trimethylolpropane triacrylate (TMPTMA, purchased from Shandong Wuwei Flame Retardant Technology Co., Ltd., purity ≥95%).

[0048] The following detailed description uses specific embodiments and comparative examples.

[0049] Preparation Example 1 The preparation method of supported composite antioxidant microparticles includes the following steps: A11. Under a nitrogen atmosphere, the active antioxidant component (the weight ratio of antioxidant 1010 to antioxidant DSTP is 2:1) is heated to a molten state, and mesoporous silica (pore size of 5nm and specific surface area of ​​700m² / g) is added to it in batches. While stirring, the vacuum degree is adjusted to -0.095MPa and maintained for 2h to obtain the first composite material. A21. While maintaining a vacuum, add γ-methacryloxypropyltrimethoxysilane as the silane coupling agent to the first composite material obtained in step A11 at a rate of 2 drops / s; heat to 80°C and react for 50 minutes to graft the silane coupling agent onto the pores of the mesoporous silica to obtain the second composite material. A31. Using atomization spraying, hydroxyl-terminated silicone oil (viscosity 800 mPa·s) is sprayed onto the surface of the second composite material obtained in step A2 at a rate of 1 mL / min, and the atomization pressure is set to 0.3 MPa. After spraying, it is cured at 80°C for 40 min in a gas stream containing humid nitrogen (relative humidity 55%) to obtain the loaded composite antioxidant microparticles.

[0050] Preparation Example 2 The preparation method of supported composite antioxidant microparticles includes the following steps: A11. Under a nitrogen atmosphere, the active antioxidant component (the weight ratio of antioxidant 1010 to antioxidant DSTP is 2:1) is heated to a molten state, and mesoporous silica (pore size of 5nm and specific surface area of ​​700m² / g) is added to it in batches. While stirring, the vacuum degree is adjusted to -0.095MPa and maintained for 2h to obtain the composite material. A21. Cool, pulverize, and pass the composite material obtained in step A11 through a 200-mesh sieve to obtain composite microparticles composed only of mesoporous silica and active antioxidant components.

[0051] Preparation Example 3 The method for preparing maleic anhydride and vinylsilane double-grafted high-density polyethylene includes the following steps: B11. Place 1000g of high-density polyethylene granules in a high-speed mixer and stir at 400 rpm for 2 minutes at room temperature. Then, add 20g of maleic anhydride, 15g of vinyl silane, 1g of initiator (diisopropylbenzene peroxide), and 3g of hindered phenolic antioxidant (Irganox 1010) in sequence and mix at 400 rpm for 8 minutes to prepare a premix. B21. The premix obtained in step B11 is fed into a twin-screw extruder at a feeding rate of 10 kg / h using a loss-in-weight feeder. The mixture is then melt-extruded and grafted at 190°C. After being cooled in a 20°C water bath and dried by air knife, the mixture is finally pelletized (3 mm in length) to obtain maleic anhydride and vinyl silane double-grafted high-density polyethylene (maleic anhydride grafting rate of 0.85% and vinyl silane grafting rate of 0.5%).

[0052] Preparation Example 4 The method for preparing maleic anhydride and vinylsilane double-grafted high-density polyethylene includes the following steps: B11. Place 1000g of high-density polyethylene granules in a high-speed mixer and stir at 400 rpm for 2 minutes at room temperature. Then, add 10g of maleic anhydride, 5g of vinyl silane, 0.3g of initiator (diisopropylbenzene peroxide), and 3g of hindered phenolic antioxidant (Irganox 1010) in sequence and mix at 400 rpm for 8 minutes to prepare a premix. B21. The premix obtained in step B11 is fed into a twin-screw extruder at a feeding rate of 10 kg / h using a loss-in-weight feeder. The mixture is then melt-extruded and grafted at 190°C. After being cooled in a 20°C water bath and dried by air knife, the mixture is finally pelletized (3 mm in length) to obtain maleic anhydride and vinyl silane double-grafted high-density polyethylene (maleic anhydride grafting rate of 0.3% and vinyl silane grafting rate of 0.1%).

[0053] Preparation Example 5 The preparation method of silane-modified magnesium hydroxide includes the following steps: C11. Add 1000g of magnesium hydroxide powder to a high-speed mixer and dry it at 110℃ and 500 rpm for 30 min. Then, dilute 10g of vinyltrimethoxysilane (VTMS) with 63g of anhydrous ethanol and spray it evenly into the high-speed mixer at a rate of 5mL / min through an atomizing nozzle. Continue to stir and mix at 500 rpm for 20 min to obtain the pre-modified product. C21. The pre-modified product obtained in step C11 is transferred to an oven and dried at 120°C for 2 hours to obtain silane-modified magnesium hydroxide.

[0054] Preparation Example 6 The preparation method of hydroxyl-terminated ultra-high molecular weight silicone powder includes the following steps: D11. Chop 1000g of hydroxyl-terminated ultra-high molecular weight silicone raw rubber (viscosity average molecular weight of 10 million, morphology of translucent creep-elastic solid rubber block) into rubber particles with a diameter of 4mm; then add the rubber particles and 500g of fumed silica to a high-speed mixer with a jacketed cooling structure. First, stir at 400 rpm for 5 minutes at room temperature, then turn on the cooling system to lower the internal temperature of the mixer to 8℃, and shear mix at 150 rpm for 15 minutes to obtain the mixture. D21. Transfer the mixture obtained in step D11 to an air jet mill equipped with a liquid nitrogen cryogenic system. The internal temperature of the mill is -120℃. Perform ultra-fine grinding at a grinding air pressure of 0.6MPa and a feed rate of 0.75kg / h to obtain ultrafine powder with a particle size distribution of 5-10μm. D31. Pass the ultrafine powder obtained in step D21 through a 200-mesh sieve under an inert atmosphere, collect the sieve residue, and obtain hydroxyl-terminated ultra-high molecular weight silicone powder (viscosity average molecular weight 1 million).

[0055] Preparation Example 7 The preparation method of hydroxyl-terminated high molecular weight silicone powder includes the following steps: D11. Add 1000g of hydroxyl-terminated high molecular weight silicone raw rubber (viscosity average molecular weight of 500,000, and form of high viscosity paste) and 800g of fumed silica to a high-speed mixer with a jacketed cooling structure. First, stir at 400 rpm for 5 minutes at room temperature. Then, turn on the cooling system to lower the internal temperature to 8°C and shear mix at 150 rpm for 15 minutes to obtain the mixture. D21. Transfer the mixture obtained in step D11 to an air jet mill equipped with a liquid nitrogen cryogenic system. The internal temperature of the mill is -120℃. Perform ultra-fine grinding at a grinding air pressure of 0.6MPa and a feed rate of 0.75kg / h to obtain ultrafine powder with a particle size distribution of 5-10μm. D31. Pass the ultrafine powder obtained in step D21 through a 200-mesh sieve under an inert atmosphere, collect the sieve residue, and obtain hydroxyl-terminated high molecular weight silicone powder (viscosity average molecular weight 500,000).

[0056] Example 1: Example 1 provides a 150°C irradiated crosslinked low-smoke halogen-free flame-retardant cable material, which, by weight, comprises the following raw materials: 55 parts high-density polyethylene, 12 parts maleic anhydride and vinyl silane double-grafted high-density polyethylene, 35 parts polyolefin elastomer, 130 parts silane-modified magnesium hydroxide, 7 parts nano sodium antimonate, 7 parts zinc borate, 3 parts loaded composite antioxidant microparticles, 4 parts hydroxyl-terminated ultra-high molecular weight silicone powder, 1.5 parts TAIC, and 0.8 parts TMPTMA.

[0057] The supported composite antioxidant microparticles, by weight, include the following raw materials: 2.6 parts mesoporous silica, 1.2 parts active antioxidant component, 0.08 parts silane coupling agent, and 0.05 parts hydroxyl-terminated silicone oil.

[0058] Among them, maleic anhydride and vinyl silane double-grafted high-density polyethylene was prepared in Preparation Example 3; supported composite antioxidant microparticles were prepared in Preparation Example 1; silane-modified magnesium hydroxide was prepared in Preparation Example 5; and hydroxyl-terminated ultra-high molecular weight silicone powder was prepared in Preparation Example 6.

[0059] The preparation method of the 150℃ irradiated cross-linked low-smoke halogen-free flame-retardant cable material in Example 1 includes the following steps: S11. High-density polyethylene, maleic anhydride and vinyl silane double-grafted high-density polyethylene, polyolefin elastomer, supported composite antioxidant microparticles, hydroxyl-terminated ultra-high molecular weight silicone powder and TAIC accounting for 66.7% of the total TAIC are placed in a first high-speed mixer and mixed at 900 rpm for 8 minutes to obtain the first premix. S21. Place the first premix obtained in step S11, silane-modified magnesium hydroxide, nano-sodium antimonate and zinc borate in a second high-speed mixer, heat to 150°C, and knead at 700 rpm for 15 minutes to obtain the second premix. S31. The second premix obtained in step S21 is placed in a two-stage extruder. In the first-stage twin-screw mixing section, the remaining TAIC and TMPTMA are dynamically homogenized by side feeding and online injection. In the second-stage single-screw section, it is extruded and pelletized at a low temperature of 160°C to obtain the 150°C irradiated crosslinked low-smoke halogen-free flame-retardant cable material of Example 1.

[0060] Example 2: Example 2 provides a 150°C irradiated crosslinked low-smoke halogen-free flame-retardant cable material, which, by weight, includes the following raw materials: 60 parts high-density polyethylene, 15 parts maleic anhydride and vinyl silane double-grafted high-density polyethylene, 40 parts polyolefin elastomer, 140 parts silane-modified magnesium hydroxide, 10 parts nano sodium antimonate, 10 parts zinc borate, 4 parts loaded composite antioxidant microparticles, 5 parts hydroxyl-terminated ultra-high molecular weight silicone powder, 2 parts TAIC and 1 part TMPTMA.

[0061] The supported composite antioxidant microparticles, by weight, include the following raw materials: 2.6 parts mesoporous silica, 1.2 parts active antioxidant component, 0.08 parts silane coupling agent, and 0.05 parts hydroxyl-terminated silicone oil.

[0062] Among them, maleic anhydride and vinyl silane double-grafted high-density polyethylene was prepared in Preparation Example 3; supported composite antioxidant microparticles were prepared in Preparation Example 1; silane-modified magnesium hydroxide was prepared in Preparation Example 5; and hydroxyl-terminated ultra-high molecular weight silicone powder was prepared in Preparation Example 6.

[0063] The preparation method of the 150℃ irradiated cross-linked low-smoke halogen-free flame-retardant cable material is the same as that in Example 1.

[0064] Example 3: Example 3 provides a 150°C irradiated crosslinked low-smoke halogen-free flame-retardant cable material, which, by weight, comprises 50 parts of high-density polyethylene, 10 parts of maleic anhydride and vinyl silane double-grafted high-density polyethylene, 30 parts of polyolefin elastomer, 120 parts of silane-modified magnesium hydroxide, 5 parts of nano-sodium antimonate, 5 parts of zinc borate, 2.5 parts of loaded composite antioxidant microparticles, 3 parts of hydroxyl-terminated ultra-high molecular weight silicone powder, 1 part of TAIC, and 0.5 parts of TMPTMA.

[0065] The supported composite antioxidant microparticles, by weight, include the following raw materials: 2.6 parts mesoporous silica, 1.2 parts active antioxidant component, 0.08 parts silane coupling agent, and 0.05 parts hydroxyl-terminated silicone oil.

[0066] Among them, maleic anhydride and vinyl silane double-grafted high-density polyethylene was prepared in Preparation Example 3; supported composite antioxidant microparticles were prepared in Preparation Example 1; silane-modified magnesium hydroxide was prepared in Preparation Example 5; and hydroxyl-terminated ultra-high molecular weight silicone powder was prepared in Preparation Example 6.

[0067] The preparation method of the 150℃ irradiated cross-linked low-smoke halogen-free flame-retardant cable material is the same as that in Example 1.

[0068] Comparative Example 1: The difference between Comparative Example 1 and Example 1 is that maleic anhydride and vinylsilane double-grafted high-density polyethylene is replaced with an equal amount of high-density polyethylene.

[0069] Comparative Example 2: The difference between Comparative Example 2 and Example 1 is that the supported composite antioxidant microparticles are replaced with an equal amount of antioxidant 1010 and antioxidant DSTP composition, wherein the weight ratio of antioxidant 1010 to antioxidant DSTP is 2:1.

[0070] Comparative Example 3: The difference between Comparative Example 3 and Example 1 is that the supported composite antioxidant microparticles were prepared by Preparation Example 2.

[0071] Comparative Example 4: The difference between Comparative Example 4 and Example 1 is that it does not include hydroxyl-terminated ultra-high molecular weight silicone powder.

[0072] Comparative Example 5: The difference between Comparative Example 5 and Example 1 is that the pore size of the supported composite antioxidant microparticle mesoporous silica is 15 nm and the specific surface area is 500 m² / g.

[0073] Comparative Example 6: The difference between Comparative Example 6 and Example 1 is that in the maleic anhydride and vinyl silane double-grafted high-density polyethylene, the maleic anhydride grafting rate is 0.3% and the vinyl silane grafting rate is 0.1%, which was prepared by Preparation Example 4.

[0074] Comparative Example 7: The difference between Comparative Example 7 and Example 1 is that the hydroxyl-terminated ultra-high molecular weight silicone powder is replaced with hydroxyl-terminated high molecular weight silicone powder (viscosity average molecular weight of 500,000), which was prepared by Example 7.

[0075] Performance testing: The cable materials prepared in each embodiment and comparative example were extruded and coated onto a 2.5 mm² copper conductor using an extruder to form a cross-linked insulated core. This core was then cross-linked by electron beam irradiation (irradiation dose of 12 Mrad). A 610 mm long insulated core (including the insulation layer and copper conductor) was cut from the irradiated core for the following tests. For smoke density testing, heat release rate testing, and precipitation level testing, the insulation layer needs to be peeled off from the irradiated core to prepare the corresponding samples.

[0076] (1) Vertical flame retardancy rating: The test was conducted in accordance with the UL1581 standard. The insulated wire core was subjected to flame 5 times, each time for 15 seconds. The self-ignition time of the insulated wire core, the burned area of ​​the indicator flag and whether the cotton below was ignited were recorded. The VW-1 rating was used as the judgment standard.

[0077] (2) Smoke density test: The insulation layer is peeled off from the insulation core, and a 75mm×75mm×1mm sample is cut. The test is carried out in accordance with GB / T 17651 (IEC 61034) standard. The transmittance is measured by a smoke density tester, and the transmittance ≥60% is used as the indicator for judging low smoke characteristics.

[0078] (3) Drip test: The test is conducted in the vertical burning test. A cotton layer is laid under the insulated wire core. The presence of molten drips, whether the drips ignite the cotton, and the duration of the drips burning are recorded. The criterion is that no drips ignite the cotton and the duration of the drips burning is ≤5s.

[0079] (4) Heat release rate test: The insulation layer is peeled off from the insulated wire core, and a 100mm×100mm×4mm sample is cut. The test is carried out in accordance with GB / T 31248 standard. The peak heat release rate (PHRR) is determined by cone calorimeter method. The lower the PHRR value, the better the flame retardant performance.

[0080] (5) Anti-aging test: The test was conducted in accordance with GB / T 2951.12 standard. The insulated wire core was placed in an oven at 150℃ for 168h for aging treatment. The tensile strength and elongation at break were measured before and after aging, and the retention rate (after aging / before aging × 100%) was calculated. The tensile strength retention rate ≥ 80% and the elongation at break retention rate ≥ 75% were taken as the passing standard.

[0081] (6) Exudation level test: Peel the insulation layer from the insulated wire core, take a flat insulation sheet, place it at 80℃ and 95% relative humidity for 7 days, and observe whether there is oily or waxy substance exuded on the surface. According to the degree of exudation, it is divided into level 0 (no exudation), level 1 (slight exudation, a small number of spots on the surface), level 2 (moderate exudation, a continuous oil film can be seen on the surface), and level 3 (severe exudation, obvious flowing exudate on the surface). Level 0 or level 1 is qualified.

[0082] The cable materials prepared in each embodiment and each comparative example were tested according to the above performance test method, and the results are shown in Table 1.

[0083] Table 1

[0084] As shown in Table 1, compared with the comparative examples, the insulated wire cores of Examples 1-3 exhibit superior performance in flame retardancy, aging resistance, and exudation resistance. Regarding flame retardancy, Examples 1-3 all achieved VW-1 level vertical flame retardancy, with smoke transmittance maintained above 70%, and peak heat release rates maintained at 200-230 kW·m. -2The levels of smoke and heat release were lower than those of the comparative examples. Furthermore, Examples 1-3 showed no dripping or ignition of cotton during the vertical burning test, while Comparative Examples 1, 4, and 6 showed slight dripping, and Comparative Example 5 showed severe dripping and ignition of cotton. This indicates that Examples 1-3 effectively suppressed smoke release, heat release, and dripping during combustion, meeting the flame retardant requirements of UL 758 standard for 150℃ heat-resistant cables, and achieving low-smoke halogen-free flame retardancy.

[0085] In terms of anti-aging performance, the tensile strength retention rate of Examples 1-3 after aging at 150℃ for 168h was all above 85%, and the elongation at break retention rate was all above 78%. In contrast, the tensile strength retention rate of each comparative example was below 76%, and the elongation at break retention rate was below 70%, which were all inferior to Examples 1-3. This indicates that each example has excellent anti-aging performance under high temperature conditions of 150℃.

[0086] In terms of precipitation performance, the precipitation levels of Examples 1-3 were all superior to those of the comparative examples, indicating that the excellent precipitation performance was not due to the supported composite antioxidant microparticles, but rather to the synergistic effect of the microparticles with the double-grafted high-density polyethylene, ultra-high molecular weight silicone powder, and other components, which together achieved the low precipitation characteristics.

[0087] In Comparative Example 1, replacing maleic anhydride and vinylsilane-grafted high-density polyethylene with an equal amount of high-density polyethylene led to decreased interfacial compatibility between silane-modified magnesium hydroxide and the polyolefin matrix. This resulted in uneven dispersion of the flame retardant within the matrix, preventing the formation of a complete and dense char layer during combustion. Consequently, the flame retardant properties of the cable material deteriorated, and slight dripping occurred. Simultaneously, the absence of vinylsilane reduced the radiation crosslinking density, and the lack of maleic anhydride weakened the interaction between polar components, leading to decreased anti-aging properties and a deterioration in the precipitation grade.

[0088] In Comparative Example 2, the loaded composite antioxidant microparticles were replaced with an equal amount of antioxidant 1010 and antioxidant DSTP. The active antioxidant components were directly dispersed in the matrix in the form of free small molecules. During high-temperature aging, they preferentially migrated and precipitated to the surface, resulting in a rapid decrease in the concentration of internal antioxidants. At the same time, the free antioxidants had a certain inhibitory effect on radiation crosslinking, thus the anti-aging performance decreased and the precipitation level deteriorated.

[0089] Comparative Example 3, because the supported composite antioxidant microparticles only include mesoporous silica and active antioxidant components, lacks the chemical sealing of the pore openings by silane coupling agents and the surface coating of hydroxyl-terminated silicone oil. Although the active antioxidant components are loaded in the pores, they will still be slowly released and precipitated during processing and aging. At the same time, it lacks the lubricating and dispersing effect of hydroxyl-terminated silicone oil. Therefore, its anti-aging performance and flame retardant performance are inferior to those of the Example.

[0090] Comparative Example 4, lacking the hydroxyl-terminated ultra-high molecular weight silicone powder, lacks the lubricating effect and internal dispersion promoting effect of silicone powder in the cable material. The uniformity of the dispersion of flame retardant particles in the matrix decreases, and the carbon layer structure is not dense enough during combustion. Therefore, the flame retardant performance deteriorates and slight dripping occurs. At the same time, the anti-aging performance and anti-exudation performance decrease.

[0091] In Comparative Example 5, the mesoporous silica had excessively large pore size and a small specific surface area, which weakened its adsorption of active antioxidant components. This resulted in a large amount of antioxidant precipitating out during processing and aging, leading to a decline in anti-aging performance. Simultaneously, the mesoporous silica itself exhibited poor dispersibility, interfering with the uniform distribution of the flame retardant. During combustion, it failed to form a complete char layer, resulting in deteriorated flame retardant performance, severe dripping, and ignition of cotton.

[0092] Comparative Example 6: Due to the low grafting rate of maleic anhydride and vinyl silane double-grafted high-density polyethylene, the interfacial compatibility between silane-modified magnesium hydroxide and the polyolefin matrix was insufficient, resulting in poor flame retardant dispersion. At the same time, the low grafting rate of vinyl silane led to insufficient crosslinking density after irradiation crosslinking, thus reducing both flame retardant and anti-aging properties.

[0093] In Comparative Example 7, due to the low viscosity and average molecular weight of the high molecular weight silicone powder with terminal hydroxyl groups, the low molecular weight silicone powder is prone to migrate and precipitate to the surface during processing and aging. At the same time, its lubrication effect is unstable, resulting in a decrease in anti-aging performance and a deterioration in precipitation level.

[0094] The above results demonstrate that this application, through the synergistic combination of load-bearing composite antioxidant microparticles with a specific structure and multiple components, enables the insulated core prepared from cable material to achieve a temperature resistance rating of 150℃ while also possessing excellent flame retardant properties, low smoke characteristics, anti-emission properties, and long-term thermo-oxidative aging stability. Since the insulated core is the core component of wires and cables, the aforementioned properties can be correspondingly imparted to wires and cables made from this insulated core.

[0095] Therefore, those skilled in the art should recognize that although numerous exemplary embodiments of the present invention have been shown and described in detail herein, many other variations or modifications conforming to the principles of the present invention can be directly determined or derived from the disclosure of the present invention without departing from the spirit and scope of the invention. Thus, the scope of the present invention should be understood and construed as covering all such other variations or modifications.

Claims

1. A 150°C radiation crosslinking low smoke halogen free flame retardant cable compound characterized in that, By weight, it includes the following raw materials: 50-60 parts high-density polyethylene, 10-15 parts maleic anhydride and vinyl silane double-grafted high-density polyethylene, 30-40 parts polyolefin elastomer, 120-140 parts silane-modified magnesium hydroxide, 5-10 parts nano sodium antimonate, 5-10 parts zinc borate, 2.5-4 parts supported composite antioxidant microparticles, 3-5 parts hydroxyl-terminated ultra-high molecular weight silicone powder, 1-2 parts sensitizing crosslinking agent and 0.5-1 parts auxiliary crosslinking agent; The supported composite antioxidant microparticles, by weight, include the following raw materials: 2.4-2.8 parts mesoporous silica, 1-1.4 parts active antioxidant component, 0.05-0.12 parts silane coupling agent, and 0.02-0.08 parts hydroxyl-terminated silicone oil.

2. The 150°C radiation crosslinking low smoke halogen-free flame retardant cable material according to claim 1, characterized in that, The mesoporous silica has a pore size of 2-10 nm, a specific surface area of 600-800 m 2 / g-800 m 2 / g.

3. The 150°C radiation crosslinking low smoke halogen-free flame retardant cable material according to claim 1, characterized in that, In the maleic anhydride and vinyl silane double-grafted high-density polyethylene, the grafting rate of maleic anhydride is 0.5%-1.2%, and the grafting rate of vinyl silane is 0.2%-0.8%.

4. The 150°C radiation crosslinking low smoke halogen-free flame retardant cable material according to claim 1, characterized in that, The viscosity of the terminal hydroxyl ultra-high molecular weight silicone powder is 800,000 to 1,200,000.

5. The 150℃ irradiated cross-linked low-smoke halogen-free flame-retardant cable material according to claim 1, characterized in that, The active antioxidant component is a composition of antioxidant 1010 and antioxidant DSTP, and the weight ratio of antioxidant 1010 to antioxidant DSTP is (1.5-2.5):

1.

6. The 150°C radiation crosslinking low smoke halogen-free flame retardant cable material according to claim 1, characterized in that, The silane coupling agent is selected from any one of γ-methacryloxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, or γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

7. The 150°C radiation crosslinking low smoke halogen-free flame retardant cable material according to claim 1, characterized in that, The sensitizing crosslinking agent is triallyl isocyanurate, and the auxiliary crosslinking agent is trimethylolpropane triacrylate.

8. The 150°C radiation crosslinking low smoke halogen-free flame retardant cable material according to claim 1, characterized in that, The preparation method of the supported composite antioxidant microparticles includes the following steps: A1. Under an inert atmosphere, the active antioxidant component is heated to a molten state, and the mesoporous silica is added to it. While stirring, the vacuum degree is adjusted to -0.09MPa to -0.1MPa and maintained for 1.5h to 3h to obtain the first composite material. A2. Add the silane coupling agent to the first composite material obtained in step A1, heat to 70℃-85℃ and react for 45min-60min. After the reaction is completed, cool, dry and pulverize to obtain the second composite material. A3. The hydroxyl-terminated silicone oil is sprayed onto the surface of the second composite material obtained in step A2 by atomization spraying, and after curing, the loaded composite antioxidant microparticles are obtained.

9. The 150°C radiation crosslinking low smoke halogen-free flame retardant cable material according to claim 1, characterized in that, The method for preparing the maleic anhydride and vinylsilane double-grafted high-density polyethylene includes the following steps: B1. A premix is ​​prepared by mixing high-density polyethylene particles, maleic anhydride, vinyl silane, initiator, and hindered phenolic antioxidant. B2. The premix obtained in step B1 is added to a twin-screw extruder and melt-extruded at a temperature of 170℃-210℃. After being cooled by water and dried, the maleic anhydride and vinyl silane double-grafted high-density polyethylene is obtained.

10. A process for the preparation of the 150°C radiation crosslinking low smoke halogen free flame retardant cable material as claimed in any one of claims 1 to 9, characterized in that, Includes the following steps: S1. High-density polyethylene, maleic anhydride and vinyl silane double-grafted high-density polyethylene, polyolefin elastomer, supported composite antioxidant microparticles, hydroxyl-terminated ultra-high molecular weight silicone powder and part of sensitizing crosslinking agent are placed in a first high-speed mixer to prepare a first premix. S2. The first premix obtained in step S1, silane-modified magnesium hydroxide, nano-sodium antimonate and zinc borate are placed in a second high-speed mixer and heated to 140℃-160℃ for intensive mixing to prepare the second premix. S3. The second premix obtained in step S2 is placed in a two-stage extruder. In the first-stage twin-screw mixing section, the remaining amount of the sensitizing crosslinking agent and auxiliary crosslinking agent are injected online through side feeding for dynamic homogenization. Then, it is extruded and pelletized at 155℃-165℃ in the second-stage single-screw section to obtain 150℃ irradiated crosslinked low-smoke halogen-free flame-retardant cable material.

Images