A flame-retardant b1 class sheath material and its use in cables

Abstract

The application discloses a kind of flame-retardant B1 grade sheath material and its application in cable, it is related to high polymer material technical field, including following by weight parts of each raw material is made: ethylene-vinyl acetate copolymer 40-50 parts, ethylene-vinyl alcohol copolymer 10-20 parts, functional hyperbranched polymer 10-20 parts, metal organic framework modified composite flame retardant 30-40 parts, compatible agent 3-5 parts, antioxidant 0.8-1.2 parts, lubricant 0.4-0.6 parts;The functional hyperbranched polymer includes following monomer introduction structure unit: thiophosphoric acid triphenyl isocyanate, N-[(4-methyl-1H-benzotriazole-1-yl) methyl] diethanolamine.This material tensile strength is big, heat shock resistance performance is sufficient, and ageing resistance performance and flame-retardant performance are excellent.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and in particular to a flame-retardant B1-grade sheath material and its application in cables. Background Technology

[0002] In the event of a fire, ensuring the uninterrupted operation of power, lighting, and communication cables, preventing chain reactions, and minimizing the release of toxic fumes is crucial not only for gaining valuable firefighting time but also for reducing loss of life and property. The cable sheath, as the most important barrier protecting the internal structure of the cable, plays a key role in preventing the spread of fire and ensuring the safety of life and property through its flame-retardant properties.

[0003] Currently, there are many types of cable sheathing materials on the market, but the flame retardant performance of many materials fails to meet high standards. Some ordinary sheathing materials are prone to combustion in the event of a fire, releasing large amounts of heat and toxic gases, which not only accelerates the spread of fire but also greatly hinders personnel evacuation and firefighting rescue efforts. Existing flame-retardant sheathing materials typically achieve their flame-retardant properties by adding large amounts of inorganic flame retardants. The addition of large amounts of inorganic flame retardants leads to a decrease in the material's mechanical properties, especially tensile strength and elongation at break, making the sheath prone to cracking during cable installation and use. Furthermore, due to compatibility issues between inorganic flame retardants and the substrate, the inorganic flame retardants are prone to leakage during long-term use, resulting in poor flame retardant stability and a short service life. In addition, other flame-retardant cable sheathing materials on the market also have technical defects to varying degrees, such as insufficient aging resistance and limited thermal shock resistance.

[0004] To address the aforementioned issues, Chinese invention patent CN112662042B discloses a B1-grade low-smoke halogen-free cable sheath material and its preparation method. The raw materials for this B1-grade low-smoke halogen-free cable sheath material include linear low-density polyethylene resin, ethylene-octene copolymer, compatibilizer, flame retardant, smoke suppressant and charring agent, and processing aids. The B1-grade low-smoke halogen-free cable sheath material prepared by this invention not only possesses excellent physical and mechanical properties but also exhibits excellent flame retardant properties and a low calorific value, meeting the B1 grade requirements of GB / T 31247 when applied to cables. However, its mechanical properties and aging resistance still require further improvement.

[0005] It is evident that there is an urgent practical need to develop a flame-retardant B1-grade sheath material with high tensile strength, sufficient thermal shock resistance, excellent aging resistance, and flame retardant properties. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a flame-retardant B1 grade sheath material with high tensile strength, sufficient thermal shock resistance, excellent aging resistance and flame retardant properties, and its application in cables.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is: a flame-retardant B1 grade sheath material, comprising the following raw materials in parts by weight: 40-50 parts of ethylene-vinyl acetate copolymer, 10-20 parts of ethylene-vinyl alcohol copolymer, 10-20 parts of functional hyperbranched polymer, 30-40 parts of metal-organic framework modified composite flame retardant, 3-5 parts of compatibilizer, 0.8-1.2 parts of antioxidant, and 0.4-0.6 parts of lubricant; wherein the functional hyperbranched polymer comprises structural units introduced by the following monomers: triphenyl isocyanate thiophosphate and N-[(4-methyl-1H-benzotriazol-1-yl)methyl]diethanolamine.

[0008] Preferably, the preparation method of the functional hyperbranched polymer includes the following steps: adding triphenyl isocyanate thiophosphate, N-[(4-methyl-1H-benzotriazol-1-yl)methyl]diethanolamine and catalyst to a high-boiling-point solvent, stirring and reacting at 80-92°C for 10-13 hours, removing the solvent by rotary evaporation, washing the crude product with diethyl ether 3-6 times, and then removing the residual diethyl ether by rotary evaporation to obtain the functional hyperbranched polymer.

[0009] Preferably, the molar ratio of the triphenyl isocyanate thiophosphate, N-[(4-methyl-1H-benzotriazol-1-yl)methyl]diethanolamine, catalyst, and high-boiling solvent is 13:10:(8-12):(60-100).

[0010] Preferably, the catalyst is at least one of stannous octoate and dibutyltin dilaurate; the high-boiling solvent is at least one of dimethyl sulfoxide and N,N-dimethylformamide.

[0011] Preferably, the ethylene-vinyl acetate copolymer is EVA1828 produced by Hanwha Chemical.

[0012] Preferably, the ethylene-vinyl alcohol copolymer is Soarnol™ DC3212B EVOH produced by Mitsubishi Chemical.

[0013] Preferably, the compatibilizer is maleic anhydride-grafted polypropylene, selected from MAH-g-PP with the brand name EXXELOR PO1020 provided by ExxonMobil, USA.

[0014] Preferably, the antioxidant is at least one of antioxidant 168, antioxidant 1010, and antioxidant 1076.

[0015] Preferably, the lubricant is calcium stearate.

[0016] Preferably, the preparation method of the metal-organic framework modified composite flame retardant includes the following steps: mixing two-dimensional layered bimetallic hydroxide, aluminum hydroxide, magnesium hydroxide, and molybdenum disulfide evenly to obtain a composite flame retardant; uniformly dispersing the composite flame retardant in N,N-dimethylformamide, then adding silane coupling agent KH560, stirring and reacting at 60-80℃ for 6-8 hours, then adding an amino-functionalized metal-organic framework, continuing to stir and react for 5-8 hours, and after the reaction is completed, removing the solvent by rotary evaporation to obtain the metal-organic framework modified composite flame retardant.

[0017] Preferably, the two-dimensional layered bimetallic hydroxide is a MgAl-LDH two-dimensional layered bimetallic hydroxide with a sheet diameter of 1-4 μm and a specific surface area of ​​11.396 m². 2 / g, grade XFL102, provided by Jiangsu Xianfeng Nanomaterials Technology Co., Ltd.

[0018] Preferably, the aluminum hydroxide has an average particle size ≤ 4.5 μm; the magnesium hydroxide has an average particle size ≤ 5 μm; and the molybdenum disulfide has an average particle size ≤ 5 μm.

[0019] Preferably, the mass ratio of the two-dimensional layered bimetallic hydroxide, aluminum hydroxide, magnesium hydroxide, molybdenum disulfide, N,N-dimethylformamide, silane coupling agent KH560, and amino-functionalized metal-organic framework is 1:(3-5):(2-4):1:(30-40):(1-2):0.5.

[0020] Preferably, there are no special requirements for the source of the amino-functionalized metal-organic framework. In one embodiment of the present invention, the amino-functionalized metal-organic framework is prepared according to the method of Embodiment 1 of the invention patent application publication number CN119591889A.

[0021] Another objective of this invention is to provide a method for preparing the flame-retardant B1 grade sheath material, comprising the following steps: mixing each raw material evenly according to the weight proportions to obtain a mixture, adding the mixture to a twin-screw extruder for extrusion, and then water-cooling, pelletizing, and drying to obtain the flame-retardant B1 grade sheath material.

[0022] Preferably, the extrusion temperature of the twin-screw extruder is: 160-170℃ in zone 1, 175-185℃ in zone 2, and 180-190℃ in zone 3, and the screw speed is 400-600 rpm.

[0023] Another object of the present invention is to provide an application of the flame-retardant B1-grade sheath material in cables.

[0024] Due to the application of the above technical solution, the present invention has the following beneficial effects:

[0025] (1) The preparation method of flame-retardant B1 grade sheath material disclosed in this invention has a simple process route, stable product quality, reasonable cost, convenient operation and control, high preparation efficiency and finished product qualification rate, low dependence on equipment, and is suitable for industrial production.

[0026] (2) The flame-retardant B1-grade sheath material disclosed in this invention is made from the following raw materials in parts by weight: 40-50 parts of ethylene-vinyl acetate copolymer, 10-20 parts of ethylene-vinyl alcohol copolymer, 10-20 parts of functional hyperbranched polymer, 30-40 parts of metal-organic framework modified composite flame retardant, 3-5 parts of compatibilizer, 0.8-1.2 parts of antioxidant, and 0.4-0.6 parts of lubricant; the functional hyperbranched polymer includes structural units introduced by the following monomers: triphenyl isocyanate thiophosphate and N-[(4-methyl-1H-benzotriazol-1-yl)methyl]diethanolamine. Through the synergistic effect of the various raw materials, the resulting sheath material exhibits high tensile strength, sufficient thermal shock resistance, excellent aging resistance, and superior flame-retardant properties, meeting the requirements of the B1 flame-retardant grade in GB / T31247-2014, and greatly improving the safety of the cable.

[0027] (3) The flame-retardant B1-grade sheath material disclosed in this invention uses ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, and functional hyperbranched polymer as the base material, combining their respective advantages and enhancing compatibility with other raw materials. This results in a sheath material with good flexibility and processing performance, excellent tensile strength and impact resistance, and good aging resistance and flame retardancy. The functional hyperbranched polymer includes structural units introduced by the following monomers: triphenyl isocyanate thiophosphate and N-[(4-methyl-1H-benzotriazole-1-yl)methyl]diethanolamine. The simultaneous introduction of triphenyl thiophosphate, benzotriazole, polyurethane, and hyperbranched structure into the polymer, under the multiple effects of electronic effect, steric hindrance effect, and conjugation effect, enables the addition of the functional hyperbranched polymer to improve the compatibility between other raw materials and improve the tensile strength, thermal shock resistance, aging resistance, and flame retardancy of the product.

[0028] (4) The flame-retardant B1-grade sheath material disclosed in this invention incorporates a metal-organic framework modified composite flame retardant, which includes a two-dimensional layered bimetallic hydroxide, aluminum hydroxide, magnesium hydroxide, and molybdenum disulfide. The combination of these flame-retardant active ingredients enhances the flame-retardant performance and stability of the finished product. The metal-organic framework modification not only improves the dispersion uniformity and compatibility with the substrate of the composite flame retardant but also further improves flame retardancy and reduces smoke density. The addition of this raw material effectively solves the environmental adaptability and high-temperature stability problems of existing flame retardants, providing a new paradigm for the development of high-safety-level materials. Detailed Implementation

[0029] The following description is intended to disclose the invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art.

[0030] Example 1

[0031] A flame-retardant B1-grade sheath material is made from the following raw materials in parts by weight: 50 parts of ethylene-vinyl acetate copolymer, 20 parts of ethylene-vinyl alcohol copolymer, 10 parts of functional hyperbranched polymer, 30 parts of metal-organic framework modified composite flame retardant, 3 parts of compatibilizer, 0.8 parts of antioxidant, and 0.4 parts of lubricant; wherein the functional hyperbranched polymer comprises structural units introduced by the following monomers: triphenyl isocyanate thiophosphate and N-[(4-methyl-1H-benzotriazol-1-yl)methyl]diethanolamine.

[0032] The preparation method of the functional hyperbranched polymer includes the following steps: adding triphenyl isocyanate thiophosphate, N-[(4-methyl-1H-benzotriazol-1-yl)methyl]diethanolamine, and a catalyst to a high-boiling-point solvent, stirring and reacting at 80°C for 10 hours, removing the solvent by rotary evaporation, washing the crude product three times with diethyl ether, and then removing the residual diethyl ether by rotary evaporation to obtain the functional hyperbranched polymer; the molar ratio of triphenyl isocyanate thiophosphate, N-[(4-methyl-1H-benzotriazol-1-yl)methyl]diethanolamine, catalyst, and high-boiling-point solvent is 13:10:8:60; the catalyst is stannous octoate; and the high-boiling-point solvent is dimethyl sulfoxide. The M of the functional hyperbranched polymer was determined by GPC testing. w =8340g.mol -1 PDI = 1.98, DB = 0.53.

[0033] The ethylene-vinyl acetate copolymer is EVA1828 produced by Hanwha Chemical; the ethylene-vinyl alcohol copolymer is SoarnolTM DC3212B EVOH produced by Mitsubishi Chemical; the compatibilizer is maleic anhydride-grafted polypropylene, selected from MAH-g-PP with the brand name EXXELOR PO1020 provided by ExxonMobil; the antioxidant is antioxidant 168; and the lubricant is calcium stearate.

[0034] The preparation method of the metal-organic framework modified composite flame retardant includes the following steps: A two-dimensional layered bimetallic hydroxide, aluminum hydroxide, magnesium hydroxide, and molybdenum disulfide are mixed evenly to obtain a composite flame retardant; the composite flame retardant is uniformly dispersed in N,N-dimethylformamide, followed by the addition of silane coupling agent KH560, and the mixture is stirred at 60°C for 6 hours. Then, an amino-functionalized metal-organic framework is added, and the mixture is stirred for another 5-8 hours. After the reaction is complete, the solvent is removed by rotary evaporation to obtain the metal-organic framework modified composite flame retardant. The two-dimensional layered bimetallic hydroxide is a MgAl-LDH two-dimensional layered bimetallic hydroxide with a sheet diameter of 1-4 μm and a specific surface area of ​​11.396 m². 2 The product, grade XFL102, is provided by Jiangsu Xianfeng Nanomaterials Technology Co., Ltd.; the average particle size of the aluminum hydroxide is ≤4.5μm; the average particle size of the magnesium hydroxide is ≤5μm; the average particle size of the molybdenum disulfide is ≤5μm; the mass ratio of the two-dimensional layered bimetallic hydroxide, aluminum hydroxide, magnesium hydroxide, molybdenum disulfide, N,N-dimethylformamide, silane coupling agent KH560, and amino-functionalized metal-organic framework is 1:3:2:1:30:1:0.5; the amino-functionalized metal-organic framework is prepared according to the method of Example 1 of the invention patent application publication number CN119591889A.

[0035] A method for preparing the flame-retardant B1 grade sheath material includes the following steps: mixing the raw materials evenly according to their weight proportions to obtain a mixture; adding the mixture to a twin-screw extruder for extrusion; and then water-cooling, pelletizing, and drying to obtain the flame-retardant B1 grade sheath material; the extrusion temperature of the twin-screw extruder is: 160℃ in zone 1, 175℃ in zone 2, and 180℃ in zone 3, and the screw speed is 400 rpm.

[0036] Application of the flame-retardant B1-grade sheath material in cables.

[0037] Example 2

[0038] A flame-retardant B1-grade sheath material is made from the following raw materials in parts by weight: 47 parts of ethylene-vinyl acetate copolymer, 18 parts of ethylene-vinyl alcohol copolymer, 13 parts of functional hyperbranched polymer, 33 parts of metal-organic framework modified composite flame retardant, 3.5 parts of compatibilizer, 0.9 parts of antioxidant, and 0.45 parts of lubricant; wherein the functional hyperbranched polymer comprises structural units introduced by the following monomers: triphenyl isocyanate thiophosphate and N-[(4-methyl-1H-benzotriazol-1-yl)methyl]diethanolamine.

[0039] The preparation method of the functional hyperbranched polymer includes the following steps: adding triphenyl isocyanate thiophosphate, N-[(4-methyl-1H-benzotriazol-1-yl)methyl]diethanolamine, and catalyst to a high-boiling-point solvent, stirring and reacting at 83°C for 11 hours, removing the solvent by rotary evaporation, washing the crude product four times with diethyl ether, and then removing the residual diethyl ether by rotary evaporation to obtain the functional hyperbranched polymer; the molar ratio of triphenyl isocyanate thiophosphate, N-[(4-methyl-1H-benzotriazol-1-yl)methyl]diethanolamine, catalyst, and high-boiling-point solvent is 13:10:9:70; the catalyst is dibutyltin dilaurate; and the high-boiling-point solvent is N,N-dimethylformamide.

[0040] The ethylene-vinyl acetate copolymer is EVA1828 produced by Hanwha Chemical; the ethylene-vinyl alcohol copolymer is SoarnolTM DC3212B EVOH produced by Mitsubishi Chemical; the compatibilizer is maleic anhydride-grafted polypropylene, selected from MAH-g-PP with the brand name EXXELOR PO1020 provided by ExxonMobil; the antioxidant is antioxidant 1010; and the lubricant is calcium stearate.

[0041] The preparation method of the metal-organic framework modified composite flame retardant includes the following steps: A two-dimensional layered bimetallic hydroxide, aluminum hydroxide, magnesium hydroxide, and molybdenum disulfide are mixed evenly to obtain a composite flame retardant; the composite flame retardant is uniformly dispersed in N,N-dimethylformamide, followed by the addition of silane coupling agent KH560, and the mixture is stirred at 65°C for 6.5 h; then an amino-functionalized metal-organic framework is added, and the mixture is stirred for another 6 h; after the reaction is complete, the solvent is removed by rotary evaporation to obtain the metal-organic framework modified composite flame retardant; the two-dimensional layered bimetallic hydroxide is MgAl-LDH two-dimensional layered bimetallic hydroxide with a sheet diameter of 1-4 μm and a specific surface area of ​​11.396 m². 2The product, grade XFL102, is provided by Jiangsu Xianfeng Nanomaterials Technology Co., Ltd.; the average particle size of the aluminum hydroxide is ≤4.5μm; the average particle size of the magnesium hydroxide is ≤5μm; the average particle size of the molybdenum disulfide is ≤5μm; the mass ratio of the two-dimensional layered bimetallic hydroxide, aluminum hydroxide, magnesium hydroxide, molybdenum disulfide, N,N-dimethylformamide, silane coupling agent KH560, and amino-functionalized metal-organic framework is 1:3.5:2.5:1:33:1.3:0.5; the amino-functionalized metal-organic framework is prepared according to the method of Example 1 of the invention patent application publication number CN119591889A.

[0042] A method for preparing the flame-retardant B1 grade sheath material includes the following steps: mixing the raw materials evenly according to their weight proportions to obtain a mixture; adding the mixture to a twin-screw extruder for extrusion; and then water-cooling, pelletizing, and drying to obtain the flame-retardant B1 grade sheath material; the extrusion temperature of the twin-screw extruder is: 163℃ in zone 1, 178℃ in zone 2, and 183℃ in zone 3, and the screw speed is 450 rpm.

[0043] Application of the flame-retardant B1-grade sheath material in cables.

[0044] Example 3

[0045] A flame-retardant B1-grade sheath material is made from the following raw materials in parts by weight: 45 parts of ethylene-vinyl acetate copolymer, 15 parts of ethylene-vinyl alcohol copolymer, 15 parts of functional hyperbranched polymer, 35 parts of metal-organic framework modified composite flame retardant, 4 parts of compatibilizer, 1 part of antioxidant, and 0.5 parts of lubricant; wherein the functional hyperbranched polymer comprises structural units introduced by the following monomers: triphenyl isocyanate thiophosphate and N-[(4-methyl-1H-benzotriazol-1-yl)methyl]diethanolamine.

[0046] The preparation method of the functional hyperbranched polymer includes the following steps: adding triphenyl isocyanate thiophosphate, N-[(4-methyl-1H-benzotriazol-1-yl)methyl]diethanolamine and catalyst to a high-boiling-point solvent, stirring and reacting at 86°C for 11.5 hours, removing the solvent by rotary evaporation, washing the crude product five times with diethyl ether, and then removing the residual diethyl ether by rotary evaporation to obtain the functional hyperbranched polymer; the molar ratio of triphenyl isocyanate thiophosphate, N-[(4-methyl-1H-benzotriazol-1-yl)methyl]diethanolamine, catalyst and high-boiling-point solvent is 13:10:10:80; the catalyst is stannous octoate; the high-boiling-point solvent is N,N-dimethylformamide.

[0047] The ethylene-vinyl acetate copolymer is EVA1828 produced by Hanwha Chemical; the ethylene-vinyl alcohol copolymer is SoarnolTM DC3212B EVOH produced by Mitsubishi Chemical; the compatibilizer is maleic anhydride-grafted polypropylene, selected from MAH-g-PP with the brand name EXXELOR PO1020 provided by ExxonMobil; the antioxidant is antioxidant 1076; and the lubricant is calcium stearate.

[0048] The preparation method of the metal-organic framework modified composite flame retardant includes the following steps: A two-dimensional layered bimetallic hydroxide, aluminum hydroxide, magnesium hydroxide, and molybdenum disulfide are mixed evenly to obtain a composite flame retardant; the composite flame retardant is uniformly dispersed in N,N-dimethylformamide, followed by the addition of silane coupling agent KH560, and the mixture is stirred at 70°C for 7 hours. Then, an amino-functionalized metal-organic framework is added, and the mixture is stirred for another 6.5 hours. After the reaction is complete, the solvent is removed by rotary evaporation to obtain the metal-organic framework modified composite flame retardant. The two-dimensional layered bimetallic hydroxide is a MgAl-LDH two-dimensional layered bimetallic hydroxide with a sheet diameter of 1-4 μm and a specific surface area of ​​11.396 m². 2 The product, grade XFL102, is provided by Jiangsu Xianfeng Nanomaterials Technology Co., Ltd.; the average particle size of the aluminum hydroxide is ≤4.5μm; the average particle size of the magnesium hydroxide is ≤5μm; the average particle size of the molybdenum disulfide is ≤5μm; the mass ratio of the two-dimensional layered bimetallic hydroxide, aluminum hydroxide, magnesium hydroxide, molybdenum disulfide, N,N-dimethylformamide, silane coupling agent KH560, and amino-functionalized metal-organic framework is 1:4:3:1:35:1.5:0.5; the amino-functionalized metal-organic framework is prepared according to the method of Example 1 of the invention patent application publication number CN119591889A.

[0049] A method for preparing the flame-retardant B1 grade sheath material includes the following steps: mixing the raw materials evenly according to their weight proportions to obtain a mixture; adding the mixture to a twin-screw extruder for extrusion; and then water-cooling, pelletizing, and drying to obtain the flame-retardant B1 grade sheath material; the extrusion temperature of the twin-screw extruder is: 165℃ in zone 1, 180℃ in zone 2, and 185℃ in zone 3, and the screw speed is 500 rpm.

[0050] Application of the flame-retardant B1-grade sheath material in cables.

[0051] Example 4

[0052] A flame-retardant B1-grade sheath material is made from the following raw materials in parts by weight: 43 parts of ethylene-vinyl acetate copolymer, 12 parts of ethylene-vinyl alcohol copolymer, 18 parts of functional hyperbranched polymer, 38 parts of metal-organic framework modified composite flame retardant, 4.5 parts of compatibilizer, 1.1 parts of antioxidant, and 0.55 parts of lubricant; wherein the functional hyperbranched polymer comprises structural units introduced by the following monomers: triphenyl isocyanate thiophosphate and N-[(4-methyl-1H-benzotriazol-1-yl)methyl]diethanolamine.

[0053] The preparation method of the functional hyperbranched polymer includes the following steps: adding triphenyl isocyanate thiophosphate, N-[(4-methyl-1H-benzotriazol-1-yl)methyl]diethanolamine, and catalyst to a high-boiling-point solvent, stirring and reacting at 90°C for 12.5 hours, removing the solvent by rotary evaporation, washing the crude product 6 times with diethyl ether, and then removing the residual diethyl ether by rotary evaporation to obtain the functional hyperbranched polymer; the molar ratio of triphenyl isocyanate thiophosphate, N-[(4-methyl-1H-benzotriazol-1-yl)methyl]diethanolamine, catalyst, and high-boiling-point solvent is 13:10:11:95; the catalyst is a mixture of stannous octoate and dibutyltin dilaurate in a mass ratio of 3:5; the high-boiling-point solvent is a mixture of dimethyl sulfoxide and N,N-dimethylformamide in a mass ratio of 1:2.

[0054] The ethylene-vinyl acetate copolymer is EVA1828 produced by Hanwha Chemical; the ethylene-vinyl alcohol copolymer is SoarnolTM DC3212B EVOH produced by Mitsubishi Chemical; the compatibilizer is maleic anhydride-grafted polypropylene, selected from MAH-g-PP with the brand name EXXELOR PO1020 provided by ExxonMobil; the antioxidant is a mixture of antioxidant 168, antioxidant 1010, and antioxidant 1076 in a mass ratio of 1:1:2; and the lubricant is calcium stearate.

[0055] The preparation method of the metal-organic framework modified composite flame retardant includes the following steps: A two-dimensional layered bimetallic hydroxide, aluminum hydroxide, magnesium hydroxide, and molybdenum disulfide are mixed evenly to obtain a composite flame retardant; the composite flame retardant is uniformly dispersed in N,N-dimethylformamide, followed by the addition of silane coupling agent KH560, and the mixture is stirred at 75°C for 7.5 h; then an amino-functionalized metal-organic framework is added, and the mixture is stirred for another 7.5 h; after the reaction is complete, the solvent is removed by rotary evaporation to obtain the metal-organic framework modified composite flame retardant; the two-dimensional layered bimetallic hydroxide is a MgAl-LDH two-dimensional layered bimetallic hydroxide with a sheet diameter of 1-4 μm and a specific surface area of ​​11.396 m². 2The product, grade XFL102, is provided by Jiangsu Xianfeng Nanomaterials Technology Co., Ltd.; the average particle size of the aluminum hydroxide is ≤4.5μm; the average particle size of the magnesium hydroxide is ≤5μm; the average particle size of the molybdenum disulfide is ≤5μm; the mass ratio of the two-dimensional layered bimetallic hydroxide, aluminum hydroxide, magnesium hydroxide, molybdenum disulfide, N,N-dimethylformamide, silane coupling agent KH560, and amino-functionalized metal-organic framework is 1:4.5:3.5:1:38:1.8:0.5; the amino-functionalized metal-organic framework is prepared according to the method of Example 1 of the invention patent application publication number CN119591889A.

[0056] A method for preparing the flame-retardant B1 grade sheath material includes the following steps: mixing the raw materials evenly according to their weight proportions to obtain a mixture; adding the mixture to a twin-screw extruder for extrusion; and then water-cooling, pelletizing, and drying to obtain the flame-retardant B1 grade sheath material; the extrusion temperature of the twin-screw extruder is: 168℃ in zone 1, 183℃ in zone 2, and 188℃ in zone 3, and the screw speed is 550 rpm.

[0057] Application of the flame-retardant B1-grade sheath material in cables.

[0058] Example 5

[0059] A flame-retardant B1-grade sheath material is made from the following raw materials in parts by weight: 40 parts of ethylene-vinyl acetate copolymer, 10 parts of ethylene-vinyl alcohol copolymer, 20 parts of functional hyperbranched polymer, 40 parts of metal-organic framework modified composite flame retardant, 5 parts of compatibilizer, 1.2 parts of antioxidant, and 0.6 parts of lubricant; wherein the functional hyperbranched polymer comprises structural units introduced by the following monomers: triphenyl isocyanate thiophosphate and N-[(4-methyl-1H-benzotriazol-1-yl)methyl]diethanolamine.

[0060] The preparation method of the functional hyperbranched polymer includes the following steps: adding triphenyl isocyanate thiophosphate, N-[(4-methyl-1H-benzotriazol-1-yl)methyl]diethanolamine and catalyst to a high-boiling-point solvent, stirring and reacting at 92°C for 13 hours, removing the solvent by rotary evaporation, washing the crude product 6 times with diethyl ether, and then removing the residual diethyl ether by rotary evaporation to obtain the functional hyperbranched polymer; the molar ratio of triphenyl isocyanate thiophosphate, N-[(4-methyl-1H-benzotriazol-1-yl)methyl]diethanolamine, catalyst and high-boiling-point solvent is 13:10:12:100; the catalyst is dibutyltin dilaurate; and the high-boiling-point solvent is dimethyl sulfoxide.

[0061] The ethylene-vinyl acetate copolymer is EVA1828 produced by Hanwha Chemical; the ethylene-vinyl alcohol copolymer is SoarnolTM DC3212B EVOH produced by Mitsubishi Chemical; the compatibilizer is maleic anhydride-grafted polypropylene, selected from MAH-g-PP with the brand name EXXELOR PO1020 provided by ExxonMobil; the antioxidant is antioxidant 168; and the lubricant is calcium stearate.

[0062] The preparation method of the metal-organic framework modified composite flame retardant includes the following steps: a two-dimensional layered bimetallic hydroxide, aluminum hydroxide, magnesium hydroxide, and molybdenum disulfide are mixed evenly to obtain a composite flame retardant; the composite flame retardant is uniformly dispersed in N,N-dimethylformamide, followed by the addition of silane coupling agent KH560, and the mixture is stirred and reacted at 80°C for 8 hours; then an amino-functionalized metal-organic framework is added, and the mixture is stirred and reacted for another 8 hours; after the reaction is complete, the solvent is removed by rotary evaporation to obtain the metal-organic framework modified composite flame retardant; the two-dimensional layered bimetallic hydroxide is a MgAl-LDH two-dimensional layered bimetallic hydroxide with a sheet diameter of 1-4 μm and a specific surface area of ​​11.396 m². 2 The product, grade XFL102, is provided by Jiangsu Xianfeng Nanomaterials Technology Co., Ltd.; the average particle size of the aluminum hydroxide is ≤4.5μm; the average particle size of the magnesium hydroxide is ≤5μm; the average particle size of the molybdenum disulfide is ≤5μm; the mass ratio of the two-dimensional layered bimetallic hydroxide, aluminum hydroxide, magnesium hydroxide, molybdenum disulfide, N,N-dimethylformamide, silane coupling agent KH560, and amino-functionalized metal-organic framework is 1:5:4:1:40:2:0.5; the amino-functionalized metal-organic framework is prepared according to the method of Example 1 of the invention patent application publication number CN119591889A.

[0063] A method for preparing the flame-retardant B1 grade sheath material includes the following steps: mixing the raw materials evenly according to their weight proportions to obtain a mixture; adding the mixture to a twin-screw extruder for extrusion; and then water-cooling, pelletizing, and drying to obtain the flame-retardant B1 grade sheath material; the extrusion temperature of the twin-screw extruder is: 170℃ in zone 1, 185℃ in zone 2, and 190℃ in zone 3, and the screw speed is 600 rpm.

[0064] Application of the flame-retardant B1-grade sheath material in cables.

[0065] Comparative Example 1

[0066] A flame-retardant B1 grade sheath material, its preparation method, and its application in cables are basically the same as in Example 1, except that an equal amount of ethylene-vinyl acetate copolymer is used instead of the functional hyperbranched polymer.

[0067] Comparative Example 2

[0068] A flame-retardant B1-grade sheath material, its preparation method, and its application in cables are basically the same as in Example 1, except that no amino-functionalized metal-organic framework is added.

[0069] To further illustrate the beneficial technical effects of the flame-retardant B1-grade sheath materials involved in the various embodiments of the present invention, relevant performance tests were conducted on the flame-retardant B1-grade sheath materials involved in Examples 1-5 and Comparative Examples 1-2. The test results are shown in Table 1. The flammability rating was determined with reference to GB / T31247-2014; other performance test methods were referenced to GB / T 32129-2015. The aging resistance was tested using an artificial accelerated aging test method according to GB / T16422.2-2014 "Laboratory Light Source Exposure Test Methods for Plastics Part 2: Xenon Arc Lamp". The sheath material sample was placed in a xenon arc lamp aging test chamber to simulate the light, temperature, and humidity conditions in the natural environment. After 1000 hours of aging, it was cooled to room temperature, and its tensile strength was measured again. The tensile strength retention rate was statistically calculated; the higher the value, the better the aging resistance. The preheating temperature in the thermal shock resistance test was 150℃.

[0070] Table 1 Performance Test Results of Flame-Retardant B1 Grade Sheath Material

[0071]

[0072] As shown in Table 1, the flame-retardant B1-grade sheath material involved in the embodiments of the present invention has better mechanical properties, flame-retardant properties, thermal shock resistance, and aging resistance than the comparative product, meeting the requirements of the B1 flame-retardant rating in GB / T 31247-2014. The combined use of functional hyperbranched polymers and amino-functionalized metal-organic frameworks is beneficial to improving the above properties.

[0073] The above embodiments are only for illustrating the technical concept and features of the present invention. Their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A flame-retardant B1-grade sheath material, characterized in that, It is made from the following raw materials in parts by weight: 40-50 parts of ethylene-vinyl acetate copolymer, 10-20 parts of ethylene-vinyl alcohol copolymer, 10-20 parts of functional hyperbranched polymer, 30-40 parts of metal-organic framework modified composite flame retardant, 3-5 parts of compatibilizer, 0.8-1.2 parts of antioxidant, and 0.4-0.6 parts of lubricant; wherein the functional hyperbranched polymer comprises structural units introduced by the following monomers: triphenyl isocyanate thiophosphate and N-[(4-methyl-1H-benzotriazol-1-yl)methyl]diethanolamine; The preparation method of the functional hyperbranched polymer includes the following steps: adding triphenyl isocyanate thiophosphate, N-[(4-methyl-1H-benzotriazol-1-yl)methyl]diethanolamine and catalyst to a high-boiling-point solvent, stirring and reacting at 80-92℃ for 10-13 hours, removing the solvent by rotary evaporation, washing the crude product with diethyl ether 3-6 times, and then removing the residual diethyl ether by rotary evaporation to obtain the functional hyperbranched polymer; the molar ratio of triphenyl isocyanate thiophosphate, N-[(4-methyl-1H-benzotriazol-1-yl)methyl]diethanolamine, catalyst and high-boiling-point solvent is 13:10:(8-12):(60-100); The preparation method of the metal-organic framework modified composite flame retardant includes the following steps: A two-dimensional layered bimetallic hydroxide, aluminum hydroxide, magnesium hydroxide, and molybdenum disulfide are mixed evenly to obtain a composite flame retardant; the composite flame retardant is evenly dispersed in N,N-dimethylformamide, followed by the addition of silane coupling agent KH560, and the mixture is stirred and reacted at 60-80℃ for 6-8 hours; then an amino-functionalized metal-organic framework is added, and the mixture is stirred and reacted for another 5-8 hours. After the reaction is complete, the solvent is removed by rotary evaporation to obtain the metal-organic framework modified composite flame retardant; the mass ratio of the two-dimensional layered bimetallic hydroxide, aluminum hydroxide, magnesium hydroxide, molybdenum disulfide, N,N-dimethylformamide, silane coupling agent KH560, and amino-functionalized metal-organic framework is 1:(3-5):(2-4):1:(30-40):(1-2):0.

5.

2. The flame-retardant B1-grade sheath material according to claim 1, characterized in that, The catalyst is at least one of stannous octoate and dibutyltin dilaurate; the high-boiling solvent is at least one of dimethyl sulfoxide and N,N-dimethylformamide.

3. The flame-retardant B1-grade sheath material according to claim 1, characterized in that, The ethylene-vinyl acetate copolymer is EVA1828 produced by Hanwha Chemical; the ethylene-vinyl alcohol copolymer is SoarnolTMDC3212B EVOH produced by Mitsubishi Chemical.

4. The flame-retardant B1-grade sheath material according to claim 1, characterized in that, The compatibilizer is maleic anhydride-grafted polypropylene, selected from MAH-g-PP with the brand name EXXELOR PO1020 provided by ExxonMobil, USA; the antioxidant is at least one of antioxidant 168, antioxidant 1010, and antioxidant 1076; and the lubricant is calcium stearate.

5. The flame-retardant B1-grade sheath material according to claim 1, characterized in that, The two-dimensional layered bimetallic hydroxide is a MgAl-LDH two-dimensional layered bimetallic hydroxide with a sheet diameter of 1-4 μm and a specific surface area of ​​11.396 m². 2 / g; the average particle size of the aluminum hydroxide is ≤4.5μm; the average particle size of the magnesium hydroxide is ≤5μm; the average particle size of the molybdenum disulfide is ≤5μm.

6. A method for preparing a flame-retardant B1-grade sheath material according to any one of claims 1-5, characterized in that, The process includes the following steps: mixing the raw materials evenly according to their weight proportions to obtain a mixture; adding the mixture to a twin-screw extruder for extrusion; and then water-cooling, pelletizing, and drying to obtain a flame-retardant B1 grade sheath material. The extrusion temperature of the twin-screw extruder is: 160-170℃ in zone 1, 175-185℃ in zone 2, and 180-190℃ in zone 3, with a screw speed of 400-600 rpm.

7. The application of a flame-retardant B1-grade sheath material according to any one of claims 1-5 in cables.

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