Flame-retardant B1-level sheath material and application thereof in cable

Abstract

The invention discloses a flame-retardant B1-grade sheath material and application thereof in cables, and relates to the technical field of high polymer materials. Comprising the following raw materials in parts by weight: 40-50 parts of an ethylene-vinyl acetate copolymer, 10-20 parts of an ethylene-vinyl alcohol copolymer, 10-20 parts of a functional hyperbranched polymer, 30-40 parts of a metal organic framework modified composite flame retardant, 3-5 parts of a compatilizer, 0.8-1.2 parts of an antioxidant and 0.4-0.6 part of a lubricant. The functional hyperbranched polymer comprises structural units introduced by the following monomers: triphenyl isocyanate thiophosphate and N-[(4-methyl-1H-benzotriazole-1-yl) methyl] diethanol amine. The material is high in tensile strength, sufficient in thermal shock resistance and excellent in aging resistance and flame retardance.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and in particular to a flame-retardant B1-level sheath material and its application in cables. Background Art

[0002] In the event of a fire, how to ensure the smooth operation of cables for power, lighting, and communication, without causing chain combustion and releasing less toxic fumes, is crucial not only for winning precious fire rescue time but also for reducing personnel and property losses. As the most important barrier for protecting the internal structure safety of cables, the flame-retardant performance of the cable sheath is the key to preventing the spread of fire and ensuring the safety of life and property.

[0003] Currently, there are a wide variety of cable sheath materials on the market, but the flame-retardant performance of many materials is difficult to meet higher standards. Some ordinary sheath materials are prone to burning and releasing a large amount of heat and toxic gases when encountering a fire, which not only accelerates the spread of the fire but also causes great obstacles to personnel evacuation and fire fighting and rescue. Existing flame-retardant sheath materials usually achieve flame-retardant performance by adding a large amount of inorganic flame retardants. The addition of a large amount of inorganic flame retardants will lead to a decline in the mechanical properties of the material, especially a decrease in tensile strength and elongation at break, making the cable prone to problems such as sheath rupture during installation and use. On the other hand, due to the compatibility problem between the inorganic flame retardant and the base material, the inorganic flame retardant is prone to exudation during long-term use, resulting in poor flame-retardant stability and short service life. In addition, other flame-retardant cable sheath materials on the market also have more or less technical defects such as insufficient aging resistance and limited heat shock resistance.

[0004] To solve the above problems, the Chinese invention patent with the authorization announcement number CN112662042B discloses a B1-level low-smoke and halogen-free cable sheath material and its preparation method. The raw materials of the B1-level low-smoke and halogen-free cable sheath material include linear low-density polyethylene resin, ethylene-octene copolymer, compatibilizer, flame retardant, smoke suppression and charring agent, and processing aids. The B1-level low-smoke and halogen-free cable sheath material prepared by this invention not only has excellent physical and mechanical properties but also has excellent flame-retardant performance and low combustion calorific value. Its application on cables can meet the B1-level requirements of GB / T 31247. However, its mechanical and mechanical properties and aging resistance still need to be further improved.

[0005] It can be seen that there is an urgent practical need to develop a flame-retardant B1-level sheath material with high tensile strength, sufficient heat shock resistance, excellent aging resistance and flame-retardant performance. Summary of the Invention

[0006] The object of the present invention is to provide a flame-retardant B1-class sheathing material with high tensile strength, sufficient heat shock resistance, excellent aging resistance and flame retardancy, and its application in cables, in order to overcome the deficiencies of the prior art.

[0007] To achieve the above object, the technical solution adopted by the present invention is: a flame-retardant B1-class sheathing material, which is made from the following raw materials 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, 0.4-0.6 parts of lubricant; the functional hyperbranched polymer includes structural units introduced by the following monomers: triphenyl thiophosphate isocyanate, 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 thiophosphate isocyanate, N-[(4-methyl-1H-benzotriazol-1-yl)methyl]diethanolamine, and catalyst into a high-boiling solvent, stirring and reacting at 80-92 °C for 10-13 hours, then rotary evaporating to remove the solvent, washing the crude product with ether 3-6 times, and then rotary evaporating to remove the residual ether to obtain the functional hyperbranched polymer.

[0009] Preferably, the molar ratio of triphenyl thiophosphate isocyanate, 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 SoarnolTM DC3212B EVOH produced by Mitsubishi Chemical.

[0013] Preferably, the compatibilizer is maleic anhydride grafted polypropylene, and the MAH-g-PP with the trade name EXXELOR PO1020 provided by Exxon in the United States is selected.

[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 comprises the following steps: uniformly mixing two-dimensional layered double metal hydroxide, aluminum hydroxide, magnesium hydroxide, and molybdenum disulfide 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 °C for 6-8 h, then adding amino-functionalized metal-organic framework, and continuing to stir and react for 5-8 h. After the reaction is completed, the solvent is removed by rotary evaporation to obtain the metal framework modified composite flame retardant.

[0017] Preferably, the two-dimensional layered double metal hydroxide is Mg Al-LDH two-dimensional layered double metal hydroxide, with a sheet diameter of 1-4 μm, a specific surface area of 11.396 m 2 / g, and the product number is XFL102, provided by Jiangsu Xianfeng Nano Materials Technology Co., Ltd.

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

[0019] Preferably, the mass ratio of the two-dimensional layered double metal 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 is no special requirement 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 Example 1 of the invention patent with the application publication number CN119591889A.

[0021] Another object of the present invention is to provide a preparation method of the flame retardant B1-grade sheath material, comprising the following steps: uniformly mixing each raw material by weight to obtain a mixed material, adding the mixed material into a twin-screw extruder for extrusion, and then through water cooling, drawing, granulating, and drying to obtain the flame retardant B1-grade sheath material.

[0022] Preferably, the extrusion temperature of the twin-screw extruder is: zone 1: 160-170 °C, zone 2: 175-185 °C, zone 3: 180-190 °C, 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 solutions, the present invention has the following beneficial effects:

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

[0026] (2) The flame-retardant B1-level sheath material disclosed by the present invention is made of 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 structural units introduced by the following monomers are included in the functional hyperbranched polymer: triphenyl thiophosphate isocyanate, N-[(4-methyl-1H-benzotriazol-1-yl)methyl]diethanolamine. Through the mutual cooperation and joint action of the raw materials, the made sheath material has high tensile strength, sufficient heat shock resistance, excellent aging resistance and flame retardancy, meets the requirements of B1 flame retardancy grade in GB / T31247-2014, and greatly improves the safety of the cable.

[0027] (3) The flame-retardant B1-level sheath material disclosed by the present invention uses a blend of ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, and functional hyperbranched polymer as the base material, combines their respective advantages, enhances the compatibility with other raw materials, and makes the made sheath material have good flexibility and processing performance, excellent tensile strength and impact resistance, and good aging resistance and flame retardancy. The structural units introduced by the following monomers are included in the functional hyperbranched polymer: triphenyl thiophosphate isocyanate, N-[(4-methyl-1H-benzotriazol-1-yl)methyl]diethanolamine; triphenyl thiophosphate, benzotriazole, polyurethane and hyperbranched structure are simultaneously introduced into the polymer. Under the multiple actions of electronic effect, steric effect and conjugation effect, etc., the addition of this functional hyperbranched polymer can improve the compatibility between other raw materials and improve the tensile strength, heat shock resistance, aging resistance and flame retardancy of the product.

[0028] (4) The flame-retardant B1-level sheath material disclosed by the present invention adds a metal-organic framework modified composite flame retardant. The composite flame retardant includes two-dimensional layered double metal hydroxide, aluminum hydroxide, magnesium hydroxide, and molybdenum disulfide. Through the compounding of these flame-retardant active ingredients, the flame-retardant performance of the manufactured product is better and the flame-retardant stability is better. Through the modification of the metal-organic framework, not only can the dispersion uniformity of the composite flame retardant and the compatibility with the substrate be improved, but also it can cooperate with the composite flame retardant to further improve the flame retardancy and reduce the smoke density. The addition of this raw material component effectively solves the problems of environmental adaptability and high-temperature stability of existing flame retardants, and provides a new paradigm for the development of high-safety-level materials. Detailed implementation mode

[0029] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments in the following description are only examples, and those skilled in the art can think of other obvious variations.

[0030] Example 1

[0031] A flame-retardant B1-level sheath material is made of the following raw materials 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 part of antioxidant, and 0.4 part of lubricant; the functional hyperbranched polymer includes structural units introduced by the following monomers: triphenyl thiophosphate isocyanate, N-[(4-methyl-1H-benzotriazol-1-yl)methyl]diethanolamine.

[0032] The preparation method of the functional hyperbranched polymer includes the following steps: Add triphenyl thiophosphate isocyanate, N-[(4-methyl-1H-benzotriazol-1-yl)methyl]diethanolamine, and catalyst to a high-boiling solvent, stir and react at 80 °C for 10 hours, then rotary evaporate to remove the solvent, wash the crude product 3 times with ether, and then rotary evaporate to remove the residual ether to obtain the functional hyperbranched polymer; the molar ratio of triphenyl thiophosphate isocyanate, N-[(4-methyl-1H-benzotriazol-1-yl)methyl]diethanolamine, catalyst, and high-boiling solvent is 13:10:8:60; the catalyst is stannous octoate; the high-boiling solvent is dimethyl sulfoxide. Through GPC testing, the M w of this functional hyperbranched polymer is 8340 g·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, and the grade is MAH-g-PP of EXXELOR PO1020 provided by ExxonMobil of the United States; the antioxidant is antioxidant 168; the lubricant is calcium stearate.

[0034] The preparation method of the metal-organic framework modified composite flame retardant comprises the following steps: uniformly mixing two-dimensional layered double metal hydroxide, aluminum hydroxide, magnesium hydroxide, and molybdenum disulfide 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 °C for 6 h, then adding amino-functionalized metal-organic framework, and continuing to stir and react for 5-8 h. After the reaction is completed, the solvent is removed by rotary evaporation to obtain the metal framework modified composite flame retardant; the two-dimensional layered double metal hydroxide is Mg Al-LDH two-dimensional layered double metal hydroxide, with a sheet diameter of 1-4 μm and a specific surface area of 11.396 m 2 / g, and the grade is XFL102, provided by Jiangsu Xianfeng Nano Materials Technology Co., Ltd.; the average particle size of the aluminum hydroxide is ≤4.5 μm; the average particle size of the magnesium hydroxide is ≤5 μm; the average particle size of the molybdenum disulfide is ≤5 μm; the mass ratio of the two-dimensional layered double metal 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 by the method of Example 1 of the invention with the application publication number CN119591889A.

[0035] A preparation method of the flame retardant B1 grade sheath material comprises the following steps: uniformly mixing each raw material by weight to obtain a mixed material, adding the mixed material into a twin-screw extruder for extrusion, and then through water cooling, drawing, granulating, and drying to obtain the flame retardant B1 grade sheath material; the extrusion temperature of the twin-screw extruder is: zone 1 at 160 °C, zone 2 at 175 °C, zone 3 at 180 °C, and the screw speed is 400 rpm.

[0036] An application of the flame retardant B1 grade sheath material in a cable.

[0037] Example 2

[0038] A flame-retardant B1-level sheath material is made from the following raw materials 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; the structural units introduced by the following monomers are included in the functional hyperbranched polymer: triphenyl thiophosphate isocyanate, N-[(4-methyl-1H-benzotriazol-1-yl)methyl]diethanolamine.

[0039] The preparation method of the functional hyperbranched polymer includes the following steps: adding triphenyl thiophosphate isocyanate, N-[(4-methyl-1H-benzotriazol-1-yl)methyl]diethanolamine, and a catalyst into a high-boiling solvent, stirring and reacting at 83 °C for 11 hours, then rotary evaporating to remove the solvent, washing the crude product 4 times with ether, and then rotary evaporating to remove the residual ether to obtain the functional hyperbranched polymer; the molar ratio of triphenyl thiophosphate isocyanate, N-[(4-methyl-1H-benzotriazol-1-yl)methyl]diethanolamine, catalyst, and high-boiling solvent is 13:10:9:70; the catalyst is dibutyltin dilaurate; the high-boiling 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, and the grade is MAH-g-PP of EXXELOR PO1020 provided by ExxonMobil of the United States; the antioxidant is antioxidant 1010; the lubricant is calcium stearate.

[0041] The preparation method of the metal-organic framework modified composite flame retardant includes the following steps: mixing two-dimensional layered double metal hydroxide, aluminum hydroxide, magnesium hydroxide, and molybdenum disulfide evenly to obtain a composite flame retardant; dispersing the composite flame retardant evenly in N,N-dimethylformamide, then adding silane coupling agent KH560, stirring and reacting at 65 °C for 6.5 h, then adding amino-functionalized metal-organic framework, and continuing to stir and react for 6 h. After the reaction, rotary evaporate to remove the solvent to obtain the metal framework modified composite flame retardant; the two-dimensional layered double metal hydroxide is Mg Al-LDH two-dimensional layered double metal hydroxide, with a sheet diameter of 1-4 μm and a specific surface area of 11.396 m 2 / g, grade XFL102, provided by Jiangsu Xianfeng Nano Material Technology Co., Ltd.; the average particle size of the aluminum hydroxide is ≤4.5 μm; the average particle size of the magnesium hydroxide is ≤5 μm; the average particle size of the molybdenum disulfide is ≤5 μm; the mass ratio of the two-dimensional layered double metal 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 by the method of Example 1 of the invention with the application publication number CN119591889A.

[0042] A preparation method of the flame-retardant B1-level sheath material includes the following steps: After mixing each raw material evenly by weight, a mixed material is obtained. The mixed material is added to a twin-screw extruder for extrusion, and then through water cooling, drawing into strips, pelletizing, and drying, a flame-retardant B1-level sheath material is obtained; the extrusion temperature of the twin-screw extruder is: Zone 1 at 163 °C, Zone 2 at 178 °C, Zone 3 at 183 °C, and the screw speed is 450 rpm.

[0043] An application of the flame-retardant B1-level sheath material in a cable.

[0044] Example 3

[0045] A flame-retardant B1-level sheath material is made of the following raw materials 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, 0.5 part of lubricant; the functional hyperbranched polymer includes structural units introduced by the following monomers: triphenyl thiophosphate isocyanate, N-[(4-methyl-1H-benzotriazol-1-yl)methyl]diethanolamine.

[0046] The preparation method of the functional hyperbranched polymer includes the following steps: Triphenyl thiophosphate isocyanate, N-[(4-methyl-1H-benzotriazol-1-yl)methyl]diethanolamine, and a catalyst are added to a high-boiling solvent, and after stirring and reacting at 86 °C for 11.5 hours, the solvent is removed by rotary evaporation. The crude product is washed 5 times with ether, and then the residual ether is removed by rotary evaporation to obtain the functional hyperbranched polymer; the molar ratio of triphenyl thiophosphate isocyanate, N-[(4-methyl-1H-benzotriazol-1-yl)methyl]diethanolamine, catalyst, and high-boiling solvent is 13:10:10:80; the catalyst is stannous octoate; the high-boiling 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 trade name EXXELOR PO1020 provided by ExxonMobil of the United States; the antioxidant is antioxidant 1076; the lubricant is calcium stearate.

[0048] The preparation method of the metal-organic framework modified composite flame retardant comprises the following steps: uniformly mixing a two-dimensional layered double metal hydroxide, aluminum hydroxide, magnesium hydroxide, and molybdenum disulfide to obtain a composite flame retardant; uniformly dispersing the composite flame retardant in N,N-dimethylformamide, then adding a silane coupling agent KH560, stirring and reacting at 70 °C for 7 h, then adding an amino-functionalized metal-organic framework, and continuing to stir and react for 6.5 h. After the reaction is completed, the solvent is removed by rotary evaporation to obtain the metal framework modified composite flame retardant; the two-dimensional layered double metal hydroxide is Mg Al-LDH two-dimensional layered double metal hydroxide, with a platelet diameter of 1-4 μm and a specific surface area of 11.396 m 2 / g, with the trade name XFL102, provided by Jiangsu Xianfeng Nano Materials Technology Co., Ltd.; the average particle size of the aluminum hydroxide is ≤4. µm; the average particle size of the magnesium hydroxide is ≤5 µm; the average particle size of the molybdenum disulfide is ≤5 µm; the mass ratio of the two-dimensional layered double metal 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 by the method of Example 1 of the invention with the application publication number CN119591889A.

[0049] A preparation method of the flame retardant B1 grade sheath material comprises the following steps: uniformly mixing each raw material by weight to obtain a mixed material, adding the mixed material into a twin-screw extruder for extrusion, and then through water cooling, drawing into strips, pelletizing, and drying to obtain the flame retardant B1 grade sheath material; the extrusion temperature of the twin-screw extruder is: zone 1 at 165 °C, zone 2 at 180 °C, zone 3 at 185 °C, and the screw speed is 500 rpm.

[0050] An application of the flame retardant B1 grade sheath material in a cable.

[0051] Example 4

[0052] A flame-retardant B1-level sheath material is made of the following raw materials 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; the functional hyperbranched polymer includes structural units introduced by the following monomers: triphenyl thiophosphate isocyanate, N-[(4-methyl-1H-benzotriazol-1-yl)methyl]diethanolamine.

[0053] The preparation method of the functional hyperbranched polymer includes the following steps: Add triphenyl thiophosphate isocyanate, N-[(4-methyl-1H-benzotriazol-1-yl)methyl]diethanolamine, and catalyst into a high-boiling solvent, stir and react at 90 °C for 12.5 hours, then rotary evaporate to remove the solvent, wash the crude product with ether 6 times, and then rotary evaporate to remove the residual ether to obtain the functional hyperbranched polymer; the molar ratio of triphenyl thiophosphate isocyanate, N-[(4-methyl-1H-benzotriazol-1-yl)methyl]diethanolamine, catalyst, and high-boiling 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 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 trade name EXXELOR PO1020 provided by ExxonMobil of the United States; the antioxidant is a mixture of antioxidant 168, antioxidant 1010, and antioxidant 1076 in a mass ratio of 1:1:2; the lubricant is calcium stearate.

[0055] The preparation method of the metal-organic framework modified composite flame retardant includes the following steps: Mix two-dimensional layered double metal hydroxide, aluminum hydroxide, magnesium hydroxide, and molybdenum disulfide evenly to obtain a composite flame retardant; Disperse the composite flame retardant evenly in N,N-dimethylformamide, then add silane coupling agent KH560, stir and react at 75 °C for 7.5 h, then add amino-functionalized metal-organic framework, and continue to stir and react for 7.5 h. After the reaction is completed, rotary evaporate to remove the solvent to obtain the metal framework modified composite flame retardant; the two-dimensional layered double metal hydroxide is Mg Al-LDH two-dimensional layered double metal hydroxide, with a sheet diameter of 1-4 μm and a specific surface area of 11.396 m 2 / g, grade XFL102, provided by Jiangsu Xianfeng Nano Material Technology Co., Ltd.; the average particle size of the aluminum hydroxide is ≤4.5 μm; the average particle size of the magnesium hydroxide is ≤5 μm; the average particle size of the molybdenum disulfide is ≤5 μm; the mass ratio of the two-dimensional layered double metal 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 by the method of Example 1 of the invention with the application publication number CN119591889A.

[0056] A preparation method of the flame-retardant B1-level sheath material comprises the following steps: mixing each raw material according to the weight parts to obtain a mixed material, adding the mixed material into a twin-screw extruder for extrusion, and then through water-cooling wire drawing, pelletizing, and drying to obtain the flame-retardant B1-level sheath material; the extrusion temperature of the twin-screw extruder is: zone 1 at 168 °C, zone 2 at 183 °C, zone 3 at 188 °C, and the screw speed is 550 rpm.

[0057] An application of the flame-retardant B1-level sheath material in a cable.

[0058] Example 5

[0059] A flame-retardant B1-level sheath material is made of the following raw materials 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; the functional hyperbranched polymer includes the structural units introduced by the following monomers: triphenyl thiophosphate isocyanate, N-[(4-methyl-1H-benzotriazol-1-yl)methyl]diethanolamine.

[0060] The preparation method of the functional hyperbranched polymer comprises the following steps: adding triphenyl thiophosphate isocyanate, N-[(4-methyl-1H-benzotriazol-1-yl)methyl]diethanolamine, and a catalyst into a high-boiling solvent, stirring and reacting at 92 °C for 13 hours, then rotary evaporating to remove the solvent, washing the crude product with ether 6 times, and then rotary evaporating to remove the residual ether to obtain the functional hyperbranched polymer; the molar ratio of triphenyl thiophosphate isocyanate, N-[(4-methyl-1H-benzotriazol-1-yl)methyl]diethanolamine, the catalyst, and the high-boiling solvent is 13:10:12:100; the catalyst is dibutyltin dilaurate; the high-boiling 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 trade name EXXELOR PO1020 provided by ExxonMobil of the United States; the antioxidant is antioxidant 168; the lubricant is calcium stearate.

[0062] The preparation method of the metal-organic framework modified composite flame retardant comprises the following steps: Mix magnesium-aluminum layered double hydroxide, aluminum hydroxide, magnesium hydroxide, and molybdenum disulfide evenly to obtain a composite flame retardant; Disperse the composite flame retardant evenly in N,N-dimethylformamide, then add silane coupling agent KH560, stir and react at 80 °C for 8 h, then add amino-functionalized metal-organic framework, continue to stir and react for 8 h. After the reaction, remove the solvent by rotary evaporation to obtain the metal framework modified composite flame retardant; The two-dimensional layered double metal hydroxide is Mg Al-LDH two-dimensional layered double metal hydroxide, with a sheet diameter of 1-4 μm and a specific surface area of 11.396 m 2 / g, with the trade name XFL102, provided by Jiangsu Xianfeng Nano Materials Technology Co., Ltd.; the average particle size of the aluminum hydroxide is ≤4.5 μm; the average particle size of the magnesium hydroxide is ≤5 μm; the average particle size of the molybdenum disulfide is ≤5 μm; The mass ratio of the two-dimensional layered double metal 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 with the application publication number CN119591889A.

[0063] A preparation method of the flame retardant B1-level sheath material comprises the following steps: Mix each raw material evenly by weight to obtain a mixed material, add the mixed material into a twin-screw extruder for extrusion, and then through water cooling, drawing into strips, pelletizing, and drying to obtain the flame retardant B1-level sheath material; The extrusion temperature of the twin-screw extruder is: Zone 1 at 170 °C, Zone 2 at 185 °C, Zone 3 at 190 °C, and the screw speed is 600 rpm.

[0064] An application of the flame retardant B1-level sheath material in cables.

[0065] Comparative Example 1

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

[0067] Comparative Example 2

[0068] A flame-retardant B1-level sheath material, its preparation method and its application in cables are basically the same as those in Example 1, except that the amino-functionalized metal-organic framework is not added.

[0069] In order to further illustrate the beneficial technical effects of the flame-retardant B1-level sheath materials involved in the embodiments of the present invention, relevant performance tests were carried out on the flame-retardant B1-level sheath materials involved in Examples 1-5 and Comparative Examples 1-2. The test results are shown in Table 1. The determination of the combustion performance level was carried out with reference to GB / T31247-2014; other performance test methods refer to GB / T 32129-2015. Among them, the aging resistance was tested by the artificial accelerated aging test method according to GB / T16422.2-2014 "Plastics - Methods of exposure to laboratory light sources - Part 2: Xenon-arc lamps". The sheath material sample was placed in a xenon-arc lamp aging test chamber to simulate the conditions of light, temperature, humidity, etc. in the natural environment. After 1000h of aging, it was cooled to room temperature, and its tensile strength was measured again. The retention rate of the tensile strength was statistically calculated. The larger the value, the better the aging resistance. The preheating temperature in the heat shock performance test was 150°C.

[0070] Table 1 Performance test results of the flame-retardant B1-level sheath material

[0071]

[0072] As can be seen from Table 1, the flame-retardant B1-level sheath materials involved in the embodiments of the present invention have better mechanical properties, flame retardancy, heat shock resistance and aging resistance than the products of the comparative examples, meeting the requirements of the B1 flame retardancy level in GB / T 31247-2014. The combined use of the functional hyperbranched polymer and the amino-functionalized metal-organic framework is beneficial to improving the above properties.

[0073] The above embodiments are only used to illustrate the technical concept and features of the present invention, and their purpose is to enable those familiar with this technology to understand the content of the present invention and implement it accordingly. It should not be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit and essence of the present invention should be covered within the protection scope of the present invention.

Claims

1. A flame-retardant B1-level sheath material, characterized in that, It is made from the following raw materials by weight parts: 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 thiophosphate isocyanate, N-[(4-methyl-1H-benzotriazol-1-yl)methyl]diethanolamine.

2. The flame-retardant B1-level sheath material according to claim 1, wherein The preparation method of the functional hyperbranched polymer includes the following steps: adding triphenyl thiophosphate isocyanate, N-[(4-methyl-1H-benzotriazol-1-yl)methyl]diethanolamine, and catalyst into a high-boiling solvent, stirring and reacting at 80-92 °C for 10-13 hours, then rotary evaporating to remove the solvent, washing the crude product with ether 3-6 times, and then rotary evaporating to remove the residual ether to obtain the functional hyperbranched polymer.

3. The flame-retardant B1-class sheath material according to claim 2, characterized in that, The molar ratio of the triphenyl thiophosphate isocyanate, N-[(4-methyl-1H-benzotriazol-1-yl)methyl]diethanolamine, catalyst, and high-boiling solvent is 13:10:(8-12):(60-100).

4. The flame-retardant B1-level sheath material according to claim 2, wherein 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.

5. The flame-retardant B1-level sheath material according to claim 1, wherein The ethylene-vinyl acetate copolymer is EVA1828 produced by Hanwha Chemical; the ethylene-vinyl alcohol copolymer is SoarnolTM DC3212B EVOH produced by Mitsubishi Chemical.

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

7. The flame-retardant B1-level sheath material according to claim 1, characterized in that, The preparation method of the metal-organic framework modified composite flame retardant includes the following steps: mixing two-dimensional layered double metal hydroxide, aluminum hydroxide, magnesium hydroxide, and molybdenum disulfide evenly to obtain a composite flame retardant; dispersing the composite flame retardant evenly in N,N-dimethylformamide, then adding silane coupling agent KH560, stirring and reacting at 60-80 °C for 6-8 h, then adding amino-functionalized metal-organic framework, and continuing to stir and react for 5-8 h. After the reaction is completed, rotary evaporate to remove the solvent to obtain the metal framework modified composite flame retardant.

8. The flame-retardant B1-class sheath material according to claim 7, characterized in that, The two-dimensional layered double metal hydroxide is a Mg Al-LDH two-dimensional layered double metal hydroxide, with a sheet diameter of 1-4 μm and a specific surface area of 11.396 m 2 / g; the average particle size of the aluminum hydroxide is ≤4.5 μm; the average particle size of the magnesium hydroxide is ≤5 μm; the average particle size of the molybdenum disulfide is ≤5 μm; the mass ratio of the two-dimensional layered double metal 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.

9. A method for preparing a flame-retardant B1-level sheath material according to any one of claims 1-8, characterized in that, It includes the following steps: mixing the raw materials by weight parts evenly to obtain a mixed material, adding the mixed material into a twin-screw extruder for extrusion, then cooling by water, drawing into strips, pelletizing, and drying to obtain a flame retardant B1-level sheath material; the extrusion temperature of the twin-screw extruder is: zone 1 160-170 °C, zone 2 175-185 °C, zone 3 180-190 °C, and the screw speed is 400-600 rpm.

10. Application of the flame retardant B1-level sheath material according to any one of claims 1-8 in a cable.

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