PE-based low-smoke halogen-free flame-retardant cable material and preparation method thereof

Abstract

The invention relates to the field of cable materials, in particular to a PE-based low-smoke halogen-free flame-retardant cable material and a preparation method thereof, and solves the problems that an existing PE-based cable material is poor in flame retardance and cannot meet the safety requirements of wires and cables in the case of fire disasters. According to the preparation method, the cable material is prepared by taking polyethylene resin as a main raw material, then the organic flame retardant and the inorganic flame retardant are added into the cable material, and through reasonable combination and synergistic effect of the organic flame retardant and the inorganic flame retardant, an efficient flame-retardant effect is achieved, the flame-retardant performance of the cable material is remarkably improved, and the risk when a fire occurs is effectively reduced; and smoke and toxic gas generated in the combustion process are less, the environmental protection requirement is met, the harm to the life safety of personnel and the environment is reduced, personnel evacuation and rescue work in a fire scene are facilitated, and wide application prospects are achieved.

Description

Technical Field

[0001] The invention relates to the field of cable materials, and in particular to a PE-based low-smoke halogen-free flame-retardant cable material and a preparation method thereof. Background Art

[0002] As an important carrier for power transmission and information transfer, wires and cables are widely used in various fields such as construction, transportation, and industry. With the development of society, people have higher and higher requirements for the safety and environmental protection of wires and cables. Traditional flame-retardant cable materials usually contain halogen additives, such as polyvinyl chloride (PVC), polybrominated ether, etc. These additives will produce toxic volumetric smoke and corrosive gases when burned, which seriously endangers human safety and the environment. At the same time, halogen combustion byproducts will also cause metal corrosion and pollute the environment. Therefore, the development of low-smoke halogen-free flame-retardant cable materials has become a research hotspot in the current cable industry.

[0003] Polyethylene (PE) is widely used in cable manufacturing due to its excellent electrical insulation, mechanical and processing properties. However, PE materials have poor flame retardancy and are difficult to meet the safety requirements of wires and cables in fire situations.

[0004] Therefore, it is of great practical significance to prepare a PE-based cable material that can meet the requirements of low smoke and halogen-free and has good flame retardant properties to meet the needs of various complex scenarios of wires and cables. Summary of the invention

[0005] In order to overcome the above technical problems, the purpose of the present invention is to provide a PE-based low-smoke halogen-free flame-retardant cable material and a preparation method thereof, which solves the problem that the existing PE-based cable materials have poor flame retardant properties and are difficult to meet the safety requirements of wires and cables in fire situations.

[0006] The purpose of the present invention can be achieved through the following technical solutions: A PE-based low-smoke halogen-free flame-retardant cable material, comprising the following components in parts by weight: 50-60 parts of polyethylene resin, 10-18 parts of organic flame retardant, 3-11 parts of inorganic flame retardant, 0.2-0.6 parts of antioxidant and 0.8-2.2 parts of lubricant; Wherein, the organic flame retardant is prepared by the following steps: Step a1: bisphenol A and trifluoroacetic acid are added to a three-necked flask equipped with a stirrer, a thermometer and an air duct, and nitrogen is introduced for protection. The mixture is stirred for reaction at a temperature of 25-30° C. and a stirring rate of 300-400 r / min for 30-40 min, and then hexamethylenetetramine is added and the temperature is raised to 90-95° C. and the stirring reaction is continued for 20-30 h. After the reaction is completed, the reaction product is cooled to room temperature, and then added to a hydrochloric acid solution and allowed to stand for 10-15 h, and then extracted with dichloromethane for 2-3 times, the extracts are combined and washed with saturated brine for 2-3 times, and then dried with anhydrous magnesium sulfate, and then vacuum filtered, and the filtrate is rotary evaporated to remove the solvent to obtain intermediate 1; Step a2: Add intermediate 1 and anhydrous ethanol to a three-necked flask equipped with a stirrer, a thermometer and an air guide tube, introduce nitrogen protection, stir and react for 10-20 minutes at a temperature of 25-30° C. and a stirring rate of 300-400 r / min, then add 4-aminophenol and continue stirring and reacting for 5-6 hours at a temperature of 80-85° C. After the reaction is completed, cool the reaction product to room temperature, pour it into ice water, and then vacuum filter it, place the filter cake in a vacuum drying oven, and dry it at a temperature of 50-55° C. for 3-4 hours to obtain intermediate 2; Step a3: Add intermediate 2, diethyl phosphite and anhydrous ethanol to a three-necked flask equipped with a stirrer, a thermometer and a gas guide tube, introduce nitrogen protection, stir and react for 10-20 minutes at a temperature of 25-30° C. and a stirring rate of 300-400 r / min, then heat to 50-55° C. and continue stirring and reacting for 10-15 hours. After the reaction is completed, the reaction product is cooled to room temperature, and then the solvent is removed by rotary evaporation, and then recrystallized with a mixed solvent to obtain intermediate 3; Step a4: Add intermediate 3, epichlorohydrin, potassium hydroxide and anhydrous ethanol to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, introduce nitrogen protection, stir and react for 20-30 minutes at a temperature of 25-30°C and a stirring rate of 300-400r / min, then heat to 70-75°C and continue to stir and react for 4-5 hours, then add potassium hydroxide solution dropwise while stirring, control the dropping rate to 1-2 drops / s, and continue to stir and react for 6-7 hours at 70-75°C after the dropwise addition is completed. After the reaction, cool the reaction product to room temperature, vacuum filter, and rotary evaporate the filtrate to remove the solvent, then add it to dichloromethane, and then wash with saturated sodium bicarbonate solution and deionized water for 2-3 times, then dry with anhydrous magnesium sulfate, and then vacuum filter, and rotary evaporate the filtrate to remove the solvent to obtain intermediate 4; Step a5: Add intermediate 4, triphenylphosphine, phenylphosphonic acid and anhydrous acetone to a three-necked flask equipped with a stirrer, a thermometer, an air duct and a reflux condenser, introduce nitrogen protection, stir the reaction for 10-20 minutes at a temperature of 25-30°C and a stirring rate of 300-400r / min, then heat the temperature to 100-105°C and continue to stir the reaction for 1-1.5 hours, then heat the temperature to 170-175°C and continue to stir the reaction for 2-3 hours. After the reaction is completed, the reaction product is cooled to room temperature, then the solvent is removed by rotary evaporation, and then recrystallized with ethyl acetate to obtain an organic flame retardant.

[0007] As a further solution of the present invention: the usage ratio of bisphenol A, trifluoroacetic acid and hexamethylenetetramine in step a1 is 10 mmol:40-45 mL:100-120 mmol.

[0008] As a further solution of the present invention: the mass fraction of the hydrochloric acid solution in step a1 is 10-15%.

[0009] As a further solution of the present invention: the usage ratio of the intermediate 1, anhydrous ethanol and 4-aminophenol in step a2 is 10 mmol:40-50 mL:22-25 mmol.

[0010] As a further solution of the present invention: the usage ratio of the intermediate 2, diethyl phosphite and anhydrous ethanol in step a3 is 10 mmol: 22-25 mmol: 50-60 mL.

[0011] As a further solution of the present invention: the mixed solvent in step a3 is N,N-dimethylformamide and deionized water mixed in equal volumes.

[0012] As a further scheme of the present invention: the usage ratio of the intermediate 3, epichlorohydrin, potassium hydroxide, anhydrous ethanol and potassium hydroxide solution in step a4 is 10mmol:60-80mmol:10-15mmol:80-100mL:10-15mL.

[0013] As a further solution of the present invention: the mass fraction of the potassium hydroxide solution in step a4 is 30-40%.

[0014] As a further scheme of the present invention: the usage ratio of the intermediate 4, triphenylphosphine, phenylphosphonic acid and anhydrous acetone in step a5 is 10 mmol: 0.3-0.5 g: 50-60 mmol: 100-120 mL.

[0015] As a further solution of the present invention: the inorganic flame retardant is prepared by the following steps: Aluminum hydroxide, deionized water and anhydrous ethanol are added to a three-necked flask equipped with a stirrer, a thermometer and an air duct, and nitrogen is introduced for protection. The reaction is stirred for 30-50 minutes at a temperature of 25-30°C and a stirring rate of 300-400r / min. Then, γ-glycidyloxypropyltrimethoxysilane is added and the stirring reaction is continued for 10-15 minutes. Then, the temperature is raised to 70-75°C and the stirring reaction is continued for 5-6 hours. After the reaction is completed, the reaction product is cooled to room temperature and then centrifuged. The precipitate is washed with anhydrous methanol for 2-3 times, and then placed in a vacuum drying oven and dried at a temperature of 50-55°C for 4-5 hours to obtain an inorganic flame retardant.

[0016] As a further solution of the present invention: the usage ratio of the aluminum hydroxide, deionized water, anhydrous ethanol and γ-glycidyloxypropyltrimethoxysilane is 5g:10-15mL:70-80mL:1.2-3.6g.

[0017] As a further solution of the present invention: a method for preparing a PE-based low-smoke halogen-free flame-retardant cable material comprises the following steps: Step 1: Weigh 50-60 parts of polyethylene resin, 10-18 parts of organic flame retardant, 3-11 parts of inorganic flame retardant, 0.2-0.6 parts of antioxidant and 0.8-2.2 parts of lubricant according to weight parts, and set aside; Step 2: Add polyethylene resin, organic flame retardant, inorganic flame retardant, antioxidant and lubricant into a high-speed mixer, and then stir and mix at a stirring rate of 350-450 r / min for 8-10 min, and then stir and mix at a stirring rate of 1100-1200 r / min for 15-20 min to obtain a mixed material; Step 3: Add the mixed material into a twin-screw extruder, melt-extrude the mixture at a screw speed of 280-320r / min and at temperatures of 155°C, 165°C, 175°C, 185°C and 195°C from the hopper to the die, and obtain a PE-based low-smoke halogen-free flame-retardant cable material after cooling and pelletizing.

[0018] As a further solution of the present invention: the polyethylene resin is a mixture of high-density polyethylene and linear low-density polyethylene in a mass ratio of 3:2.

[0019] As a further solution of the present invention: the antioxidant is a mixture of antioxidant 626 and antioxidant 1010 in a mass ratio of 2:1.

[0020] As a further solution of the present invention: the lubricant is a mixture of magnesium stearate and vinyl bisstearamide in a mass ratio of 2:1.

[0021] Beneficial effects of the present invention: The invention discloses a PE-based low-smoke halogen-free flame-retardant cable material and a preparation method thereof. The method comprises the following steps: adding polyethylene resin, an organic flame retardant, an inorganic flame retardant, an antioxidant and a lubricant into a high-speed stirrer for stirring and mixing to obtain a mixture, adding the mixture into a twin-screw extruder for melt extrusion, and obtaining the PE-based low-smoke halogen-free flame-retardant cable material after cooling and pelletizing. The preparation method uses polyethylene resin as a main raw material to prepare the cable material, and then adds an organic flame retardant and an inorganic flame retardant thereto. Through a reasonable combination of the two, a high-efficiency flame retardant effect is achieved under synergistic effect, the flame retardant performance of the cable material is significantly improved, the risk of fire is effectively reduced, less smoke and toxic gas are generated during the combustion process, environmental protection requirements are met, the harm to personnel life safety and the environment is reduced, and personnel evacuation and rescue work at the fire scene are facilitated. The method has broad application prospects.

[0022] In the process of preparing the PE-based low-smoke halogen-free flame-retardant cable material, an organic flame retardant is first prepared. First, bisphenol A is used as a raw material, and hexamethylenetetramine is used to formylate bisphenol A. After Duff aldehyde reaction, an aldehyde group is introduced into the benzene ring of bisphenol A to obtain intermediate 1. Then, intermediate 1 and 4-aminophenol are reacted, and the aldehyde group on intermediate 1 reacts with the amino group on 4-aminophenol to form a Schiff base structure to obtain intermediate 2. Then, intermediate 2 and diethyl phosphite are reacted, and the C=N bond on intermediate 2 reacts with the PH bond on diethyl phosphite to undergo addition reaction, and an organic phosphorus structure and a hydroxyl group are introduced to obtain intermediate 3. Then, intermediate 3 and epichlorohydrin are reacted, and the hydroxyl group on intermediate 3 reacts with epichlorohydrin through opening After the ring-closing reaction, a large number of epoxy groups are introduced to obtain intermediate 4, and then intermediate 4 and phenylphosphonic acid react, and the epoxy group on intermediate 4 reacts with P-OH on phenylphosphonic acid to further form an organic phosphorus structure to obtain an organic flame retardant; the molecular structure of the organic flame retardant contains a large number of benzene rings, organic nitrogen structures and organic phosphorus structures. The large number of benzene rings give it excellent thermal stability, making it difficult to ignite, and the organic phosphorus can promote the dehydration and carbonization of organic matter during combustion, and can prevent the transfer of heat and the diffusion of oxygen. The organic nitrogen can produce a large amount of non-combustible gas during the combustion process, which can dilute or even isolate the combustible gas, giving it excellent flame retardant properties. It is used in cable materials to greatly improve the flame retardant properties of cable materials.

[0023] In the process of preparing the PE-based low-smoke halogen-free flame-retardant cable material, an inorganic flame retardant is also prepared. Aluminum hydroxide and γ-glycidyloxypropyltrimethoxysilane are reacted, and the siloxane on the γ-glycidyloxypropyltrimethoxysilane is hydrolyzed to form silanol grafted to the surface of aluminum hydroxide particles, which are wrapped, and epoxy groups are introduced to obtain an inorganic flame retardant. After being wrapped, the inorganic flame retardant can improve the compatibility of aluminum hydroxide with cable materials, avoid their agglomeration, and enable them to be evenly distributed in the cable material. The presence of the epoxy group enables it to be chemically bonded with other components in the cable material, further improving its interfacial bonding strength. Moreover, aluminum hydroxide can be thermally decomposed at high temperatures and absorb a large amount of heat, while releasing water vapor, thereby reducing the concentration of oxygen and combustible gases, making it impossible for combustion to continue, thereby achieving the purpose of flame retardancy. DETAILED DESCRIPTION

[0024] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] Embodiment 1: This embodiment is a method for preparing a PE-based low-smoke halogen-free flame-retardant cable material, comprising the following steps: Step S1: 10 mmol bisphenol A and 40 mL trifluoroacetic acid are added to a three-necked flask equipped with a stirrer, a thermometer and an air duct, and nitrogen is introduced for protection. The mixture is stirred for reaction at a temperature of 25° C. and a stirring rate of 300 r / min for 30 min, and then 100 mmol hexamethylenetetramine is added and the mixture is heated to 90° C. and stirred for reaction for 20 h. After the reaction is completed, the reaction product is cooled to room temperature, and then added to a 10% hydrochloric acid solution and allowed to stand for 10 h. The mixture is then extracted with dichloromethane twice, the extracts are combined and washed with saturated brine twice, and then dried with anhydrous magnesium sulfate, and then vacuum filtered. The filtrate is rotary evaporated to remove the solvent to obtain intermediate 1; Step S2: 10 mmol of intermediate 1 and 40 mL of anhydrous ethanol were added to a three-necked flask equipped with a stirrer, a thermometer and an air guide tube, and nitrogen was introduced for protection. The mixture was stirred for reaction at a temperature of 25° C. and a stirring rate of 300 r / min for 10 min. Then, 22 mmol of 4-aminophenol was added and the temperature was raised to 80° C. and the stirring reaction was continued for 5 h. After the reaction was completed, the reaction product was cooled to room temperature and then poured into ice water. After vacuum filtration, the filter cake was placed in a vacuum drying oven and dried at a temperature of 50° C. for 3 h to obtain intermediate 2; Step S3: 10 mmol of intermediate 2, 22 mmol of diethyl phosphite and 50 mL of anhydrous ethanol were added to a three-necked flask equipped with a stirrer, a thermometer and a gas guide tube, and nitrogen was introduced for protection. The mixture was stirred at 25° C. and a stirring rate of 300 r / min for 10 min, and then the mixture was heated to 50° C. and the stirring reaction was continued for 10 h. After the reaction was completed, the reaction product was cooled to room temperature, and then the solvent was removed by rotary evaporation. Then, the mixture was recrystallized with a mixed solvent of equal volumes of N,N-dimethylformamide and deionized water to obtain intermediate 3; Step S4: 10 mmol of intermediate 3, 60 mmol of epichlorohydrin, 10 mmol of potassium hydroxide and 80 mL of anhydrous ethanol are added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and nitrogen is introduced for protection. The mixture is stirred for reaction at a temperature of 25° C. and a stirring rate of 300 r / min for 20 min, and then the mixture is heated to 70° C. and the stirring reaction is continued for 4 h. Then, 10 mL of a 30% potassium hydroxide solution by mass is added dropwise while stirring, and the dropping rate is controlled to be 1 drop / s. After the addition is completed, the mixture is heated to 70° C. and the stirring reaction is continued for 6 h. After the reaction is completed, the reaction product is cooled to room temperature, and then vacuum filtered, the filtrate is rotary evaporated to remove the solvent, and then added to dichloromethane, and then washed twice with a saturated sodium bicarbonate solution and deionized water in sequence, and then dried with anhydrous magnesium sulfate, and then vacuum filtered, and the filtrate is rotary evaporated to remove the solvent to obtain intermediate 4; Step S5: 10 mmol of intermediate 4, 0.3 g of triphenylphosphine, 50 mmol of phenylphosphonic acid and 100 mL of anhydrous acetone were added to a three-necked flask equipped with a stirrer, a thermometer, a gas duct and a reflux condenser, and nitrogen was introduced for protection. The mixture was stirred for reaction at a temperature of 25° C. and a stirring rate of 300 r / min for 10 min, and then the mixture was heated to 100° C. and the stirring reaction was continued for 1 h. The mixture was heated to 170° C. and the stirring reaction was continued for 2 h. After the reaction was completed, the reaction product was cooled to room temperature, and then the solvent was removed by rotary evaporation, and then recrystallized from ethyl acetate to obtain an organic flame retardant; Step S6: 5 g of aluminum hydroxide, 10 mL of deionized water and 70 mL of anhydrous ethanol were added to a three-necked flask equipped with a stirrer, a thermometer and an air duct, and nitrogen was introduced for protection. The mixture was stirred for reaction at a temperature of 25° C. and a stirring rate of 300 r / min for 30 min, and then 1.2 g of γ-glycidyloxypropyltrimethoxysilane was added and the stirring reaction was continued for 10 min. The mixture was then heated to 70° C. and the stirring reaction was continued for 5 h. After the reaction was completed, the reaction product was cooled to room temperature and then centrifuged. The precipitate was washed twice with anhydrous methanol, and then placed in a vacuum drying oven and dried at a temperature of 50° C. for 4 h to obtain an inorganic flame retardant. Step S7: weigh 50 parts of polyethylene resin, 10 parts of organic flame retardant, 3 parts of inorganic flame retardant, 0.2 parts of antioxidant and 0.8 parts of lubricant according to weight parts for use; the polyethylene resin is a mixture of high-density polyethylene and linear low-density polyethylene in a mass ratio of 3:2; the antioxidant is a mixture of antioxidant 626 and antioxidant 1010 in a mass ratio of 2:1; the lubricant is a mixture of magnesium stearate and vinyl bisstearamide in a mass ratio of 2:1; Step S8: adding polyethylene resin, organic flame retardant, inorganic flame retardant, antioxidant and lubricant into a high-speed mixer, and then stirring and mixing at a stirring rate of 350 r / min for 8 minutes, and then stirring and mixing at a stirring rate of 1100 r / min for 15 minutes to obtain a mixed material; Step S9: adding the mixture into a twin-screw extruder, and melt-extrude the mixture at a screw speed of 280 r / min and temperatures of 155° C., 165° C., 175° C., 185° C., and 195° C. from the hopper to the die, respectively. After cooling and pelletizing, a PE-based low-smoke halogen-free flame-retardant cable material is obtained.

[0026] Embodiment 2: This embodiment is a method for preparing a PE-based low-smoke halogen-free flame-retardant cable material, comprising the following steps: Step S1: 10 mmol bisphenol A and 42 mL trifluoroacetic acid are added to a three-necked flask equipped with a stirrer, a thermometer and an air duct, and nitrogen is introduced for protection. The reaction is stirred for 35 minutes at a temperature of 28° C. and a stirring rate of 350 r / min. Then, 110 mmol hexamethylenetetramine is added and the temperature is raised to 92° C. and the stirring reaction is continued for 25 hours. After the reaction is completed, the reaction product is cooled to room temperature, and then added to a hydrochloric acid solution with a mass fraction of 12% and allowed to stand for 12 hours. Then, the product is extracted with dichloromethane twice, the extracts are combined and washed with saturated brine twice, and then dried with anhydrous magnesium sulfate. Then, the product is vacuum filtered, and the filtrate is rotary evaporated to remove the solvent to obtain intermediate 1; Step S2: 10 mmol of intermediate 1 and 45 mL of anhydrous ethanol were added to a three-necked flask equipped with a stirrer, a thermometer and an air guide tube, and nitrogen was introduced for protection. The mixture was stirred for reaction at 28° C. and a stirring rate of 350 r / min for 15 min. Then, 24 mmol of 4-aminophenol was added and the mixture was heated to 82° C. and the stirring reaction was continued for 5.5 h. After the reaction was completed, the reaction product was cooled to room temperature and then poured into ice water. After vacuum filtration, the filter cake was placed in a vacuum drying oven and dried at 52° C. for 3.5 h to obtain intermediate 2; Step S3: 10 mmol of intermediate 2, 24 mmol of diethyl phosphite and 55 mL of anhydrous ethanol were added to a three-necked flask equipped with a stirrer, a thermometer and a gas guide tube, and nitrogen was introduced for protection. The mixture was stirred at 28° C. and a stirring rate of 350 r / min for 15 min, and then the mixture was heated to 52° C. and continued to stir for 12 h. After the reaction was completed, the reaction product was cooled to room temperature, and then the solvent was removed by rotary evaporation. The mixture was then recrystallized with a mixed solvent of equal volumes of N,N-dimethylformamide and deionized water to obtain intermediate 3; Step S4: 10 mmol of intermediate 3, 70 mmol of epichlorohydrin, 12 mmol of potassium hydroxide and 90 mL of anhydrous ethanol are added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and nitrogen is introduced for protection. The reaction is stirred for 25 min at a temperature of 28 ° C and a stirring rate of 350 r / min, and then the temperature is raised to 72 ° C and the stirring reaction is continued for 4.5 h. Then, 12 mL of a 35% potassium hydroxide solution by mass is added dropwise while stirring, and the dropping rate is controlled to be 1 drop / s. After the dropwise addition is completed, the temperature is raised to 72 ° C and the stirring reaction is continued for 6.5 h. After the reaction is completed, the reaction product is cooled to room temperature, and then vacuum filtered, the filtrate is rotary evaporated to remove the solvent, and then added to dichloromethane, and then washed twice with saturated sodium bicarbonate solution and deionized water in sequence, and then dried with anhydrous magnesium sulfate, and then vacuum filtered, and the filtrate is rotary evaporated to remove the solvent to obtain intermediate 4; Step S5: 10 mmol of intermediate 4, 0.4 g of triphenylphosphine, 55 mmol of phenylphosphonic acid and 110 mL of anhydrous acetone were added to a three-necked flask equipped with a stirrer, a thermometer, a gas duct and a reflux condenser, and nitrogen was introduced for protection. The mixture was stirred for reaction at a temperature of 28° C. and a stirring rate of 350 r / min for 15 min, and then the mixture was heated to 102° C. and the stirring reaction was continued for 1.2 h. The mixture was then heated to 172° C. and the stirring reaction was continued for 2.5 h. After the reaction was completed, the reaction product was cooled to room temperature, and then the solvent was removed by rotary evaporation, and then recrystallized from ethyl acetate to obtain an organic flame retardant; Step S6: 5 g of aluminum hydroxide, 12 mL of deionized water and 75 mL of anhydrous ethanol were added to a three-necked flask equipped with a stirrer, a thermometer and an air duct, and nitrogen was introduced for protection. The mixture was stirred for reaction at a temperature of 28° C. and a stirring rate of 350 r / min for 40 min, and then 2.4 g of γ-glycidyloxypropyltrimethoxysilane was added and the stirring reaction was continued for 12 min. The mixture was then heated to 72° C. and the stirring reaction was continued for 5.5 h. After the reaction was completed, the reaction product was cooled to room temperature and then centrifuged. The precipitate was washed twice with anhydrous methanol, and then placed in a vacuum drying oven and dried at a temperature of 52° C. for 4.5 h to obtain an inorganic flame retardant. Step S7: 55 parts of polyethylene resin, 14 parts of organic flame retardant, 7 parts of inorganic flame retardant, 0.4 parts of antioxidant and 1.5 parts of lubricant are weighed in parts by weight for later use; the polyethylene resin is a mixture of high-density polyethylene and linear low-density polyethylene in a mass ratio of 3:2; the antioxidant is a mixture of antioxidant 626 and antioxidant 1010 in a mass ratio of 2:1; the lubricant is a mixture of magnesium stearate and vinyl bisstearamide in a mass ratio of 2:1; Step S8: adding polyethylene resin, organic flame retardant, inorganic flame retardant, antioxidant and lubricant into a high-speed mixer, stirring and mixing at a stirring rate of 400 r / min for 9 minutes, and then stirring and mixing at a stirring rate of 1150 r / min for 18 minutes to obtain a mixed material; Step S9: adding the mixture into a twin-screw extruder, and melt-extrude the mixture at a screw speed of 300 r / min and temperatures of 155° C., 165° C., 175° C., 185° C., and 195° C. from the hopper to the die, respectively. After cooling and pelletizing, a PE-based low-smoke halogen-free flame-retardant cable material is obtained.

[0027] Embodiment 3: This embodiment is a method for preparing a PE-based low-smoke halogen-free flame-retardant cable material, comprising the following steps: Step S1: 10 mmol bisphenol A and 45 mL trifluoroacetic acid are added to a three-necked flask equipped with a stirrer, a thermometer and an air guide tube, and nitrogen is introduced for protection. The mixture is stirred for reaction at a temperature of 30° C. and a stirring rate of 400 r / min for 40 min, and then 120 mmol hexamethylenetetramine is added and the mixture is heated to 95° C. and stirred for reaction for 30 h. After the reaction is completed, the reaction product is cooled to room temperature, and then added to a 15% hydrochloric acid solution and allowed to stand for 15 h. The mixture is then extracted with dichloromethane for 3 times, the extracts are combined and washed with saturated brine for 3 times, and then dried with anhydrous magnesium sulfate. The mixture is then vacuum filtered, and the filtrate is rotary evaporated to remove the solvent to obtain intermediate 1; Step S2: 10 mmol of intermediate 1 and 50 mL of anhydrous ethanol were added to a three-necked flask equipped with a stirrer, a thermometer and an air guide tube, and nitrogen was introduced for protection. The mixture was stirred for reaction at a temperature of 30° C. and a stirring rate of 400 r / min for 20 min. Then, 25 mmol of 4-aminophenol was added and the temperature was raised to 85° C. and the stirring reaction was continued for 6 h. After the reaction was completed, the reaction product was cooled to room temperature and then poured into ice water. After vacuum filtration, the filter cake was placed in a vacuum drying oven and dried at a temperature of 55° C. for 4 h to obtain intermediate 2; Step S3: 10 mmol of intermediate 2, 25 mmol of diethyl phosphite and 60 mL of anhydrous ethanol were added to a three-necked flask equipped with a stirrer, a thermometer and a gas guide tube, and nitrogen was introduced for protection. The mixture was stirred at a temperature of 30° C. and a stirring rate of 400 r / min for 20 min, and then the mixture was heated to 55° C. and continued to stir for 15 h. After the reaction was completed, the reaction product was cooled to room temperature, and then the solvent was removed by rotary evaporation, and then recrystallized with a mixed solvent of equal volumes of N, N-dimethylformamide and deionized water to obtain intermediate 3; Step S4: 10 mmol of intermediate 3, 80 mmol of epichlorohydrin, 15 mmol of potassium hydroxide and 100 mL of anhydrous ethanol are added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and nitrogen is introduced for protection. The mixture is stirred for reaction at a temperature of 30° C. and a stirring rate of 400 r / min for 30 min, and then the mixture is heated to 75° C. and the stirring reaction is continued for 5 h. Then, 15 mL of a 40% potassium hydroxide solution by mass is added dropwise while stirring, and the dropping rate is controlled to be 2 drops / s. After the dropwise addition is completed, the mixture is heated to 75° C. and the stirring reaction is continued for 7 h. After the reaction is completed, the reaction product is cooled to room temperature, and then vacuum filtered, the filtrate is rotary evaporated to remove the solvent, and then added to dichloromethane, and then washed with saturated sodium bicarbonate solution and deionized water for 3 times in sequence, and then dried with anhydrous magnesium sulfate, and then vacuum filtered, and the filtrate is rotary evaporated to remove the solvent to obtain intermediate 4; Step S5: 10 mmol of intermediate 4, 0.5 g of triphenylphosphine, 60 mmol of phenylphosphonic acid and 120 mL of anhydrous acetone were added to a three-necked flask equipped with a stirrer, a thermometer, a gas duct and a reflux condenser, and nitrogen was introduced for protection. The mixture was stirred for reaction at a temperature of 30° C. and a stirring rate of 400 r / min for 20 min, and then the mixture was heated to 105° C. and the stirring reaction was continued for 1.5 h. The mixture was then heated to 175° C. and the stirring reaction was continued for 3 h. After the reaction was completed, the reaction product was cooled to room temperature, and then the solvent was removed by rotary evaporation, and then recrystallized from ethyl acetate to obtain an organic flame retardant; Step S6: 5 g of aluminum hydroxide, 15 mL of deionized water and 80 mL of anhydrous ethanol were added to a three-necked flask equipped with a stirrer, a thermometer and an air duct, and nitrogen was introduced for protection. The mixture was stirred for reaction at a temperature of 30° C. and a stirring rate of 400 r / min for 50 min, and then 3.6 g of γ-glycidyloxypropyltrimethoxysilane was added and the stirring reaction was continued for 15 min. The mixture was then heated to 75° C. and the stirring reaction was continued for 6 h. After the reaction was completed, the reaction product was cooled to room temperature and then centrifuged. The precipitate was washed 3 times with anhydrous methanol, and then placed in a vacuum drying oven and dried at a temperature of 55° C. for 5 h to obtain an inorganic flame retardant. Step S7: weigh 60 parts of polyethylene resin, 18 parts of organic flame retardant, 11 parts of inorganic flame retardant, 0.6 parts of antioxidant and 2.2 parts of lubricant according to weight parts for use; the polyethylene resin is a mixture of high-density polyethylene and linear low-density polyethylene in a mass ratio of 3:2; the antioxidant is a mixture of antioxidant 626 and antioxidant 1010 in a mass ratio of 2:1; the lubricant is a mixture of magnesium stearate and vinyl bisstearamide in a mass ratio of 2:1; Step S8: adding polyethylene resin, organic flame retardant, inorganic flame retardant, antioxidant and lubricant into a high-speed mixer, and then stirring and mixing at a stirring rate of 450 r / min for 10 min, and then stirring and mixing at a stirring rate of 1200 r / min for 20 min to obtain a mixed material; Step S9: adding the mixture into a twin-screw extruder, and melt-extrude the mixture at a screw speed of 320 r / min and temperatures of 155° C., 165° C., 175° C., 185° C., and 195° C. from the hopper to the die, respectively. After cooling and pelletizing, a PE-based low-smoke halogen-free flame-retardant cable material is obtained.

[0028] Comparative Example 1: This comparative example is a method for preparing a PE-based low-smoke halogen-free flame-retardant cable material, comprising the following steps: Step S1: 60 parts of polyethylene resin, 0.6 parts of antioxidant and 2.2 parts of lubricant are weighed in parts by weight for later use; the polyethylene resin is a mixture of high-density polyethylene and linear low-density polyethylene in a mass ratio of 3:2; the antioxidant is a mixture of antioxidant 626 and antioxidant 1010 in a mass ratio of 2:1; the lubricant is a mixture of magnesium stearate and vinyl bisstearamide in a mass ratio of 2:1; Step S2: adding polyethylene resin, antioxidant and lubricant into a high-speed mixer, and then stirring and mixing them at a stirring rate of 450 r / min for 10 min, and then stirring and mixing them at a stirring rate of 1200 r / min for 20 min to obtain a mixed material; Step S3: adding the mixture into a twin-screw extruder, and melt-extrude the mixture at a screw speed of 320 r / min and temperatures of 155° C., 165° C., 175° C., 185° C., and 195° C. from the hopper to the die, respectively, to obtain a PE-based low-smoke halogen-free flame-retardant cable material after cooling and pelletizing.

[0029] Comparative Example 2: This comparative example is a method for preparing a PE-based low-smoke halogen-free flame-retardant cable material, comprising the following steps: Step S1: 10 mmol bisphenol A and 45 mL trifluoroacetic acid are added to a three-necked flask equipped with a stirrer, a thermometer and an air guide tube, and nitrogen is introduced for protection. The mixture is stirred for reaction at a temperature of 30° C. and a stirring rate of 400 r / min for 40 min, and then 120 mmol hexamethylenetetramine is added and the mixture is heated to 95° C. and stirred for reaction for 30 h. After the reaction is completed, the reaction product is cooled to room temperature, and then added to a 15% hydrochloric acid solution and allowed to stand for 15 h. The mixture is then extracted with dichloromethane for 3 times, the extracts are combined and washed with saturated brine for 3 times, and then dried with anhydrous magnesium sulfate. The mixture is then vacuum filtered, and the filtrate is rotary evaporated to remove the solvent to obtain intermediate 1; Step S2: 10 mmol of intermediate 1 and 50 mL of anhydrous ethanol were added to a three-necked flask equipped with a stirrer, a thermometer and an air guide tube, and nitrogen was introduced for protection. The mixture was stirred for reaction at a temperature of 30° C. and a stirring rate of 400 r / min for 20 min. Then, 25 mmol of 4-aminophenol was added and the temperature was raised to 85° C. and the stirring reaction was continued for 6 h. After the reaction was completed, the reaction product was cooled to room temperature and then poured into ice water. After vacuum filtration, the filter cake was placed in a vacuum drying oven and dried at a temperature of 55° C. for 4 h to obtain intermediate 2; Step S3: 10 mmol of intermediate 2, 25 mmol of diethyl phosphite and 60 mL of anhydrous ethanol were added to a three-necked flask equipped with a stirrer, a thermometer and a gas guide tube, and nitrogen was introduced for protection. The mixture was stirred at a temperature of 30° C. and a stirring rate of 400 r / min for 20 min, and then the mixture was heated to 55° C. and continued to stir for 15 h. After the reaction was completed, the reaction product was cooled to room temperature, and then the solvent was removed by rotary evaporation, and then recrystallized with a mixed solvent of equal volumes of N, N-dimethylformamide and deionized water to obtain intermediate 3; Step S4: 10 mmol of intermediate 3, 80 mmol of epichlorohydrin, 15 mmol of potassium hydroxide and 100 mL of anhydrous ethanol are added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and nitrogen is introduced for protection. The mixture is stirred for reaction at a temperature of 30° C. and a stirring rate of 400 r / min for 30 min, and then the mixture is heated to 75° C. and the stirring reaction is continued for 5 h. Then, 15 mL of a 40% potassium hydroxide solution by mass is added dropwise while stirring, and the dropping rate is controlled to be 2 drops / s. After the dropwise addition is completed, the mixture is heated to 75° C. and the stirring reaction is continued for 7 h. After the reaction is completed, the reaction product is cooled to room temperature, and then vacuum filtered, the filtrate is rotary evaporated to remove the solvent, and then added to dichloromethane, and then washed with saturated sodium bicarbonate solution and deionized water for 3 times in sequence, and then dried with anhydrous magnesium sulfate, and then vacuum filtered, and the filtrate is rotary evaporated to remove the solvent to obtain intermediate 4; Step S5: 10 mmol of intermediate 4, 0.5 g of triphenylphosphine, 60 mmol of phenylphosphonic acid and 120 mL of anhydrous acetone were added to a three-necked flask equipped with a stirrer, a thermometer, a gas duct and a reflux condenser, and nitrogen was introduced for protection. The mixture was stirred for reaction at a temperature of 30° C. and a stirring rate of 400 r / min for 20 min, and then the mixture was heated to 105° C. and the stirring reaction was continued for 1.5 h. The mixture was then heated to 175° C. and the stirring reaction was continued for 3 h. After the reaction was completed, the reaction product was cooled to room temperature, and then the solvent was removed by rotary evaporation, and then recrystallized from ethyl acetate to obtain an organic flame retardant; Step S6: 60 parts of polyethylene resin, 18 parts of organic flame retardant, 0.6 parts of antioxidant and 2.2 parts of lubricant are weighed in parts by weight for later use; the polyethylene resin is a mixture of high-density polyethylene and linear low-density polyethylene in a mass ratio of 3:2; the antioxidant is a mixture of antioxidant 626 and antioxidant 1010 in a mass ratio of 2:1; the lubricant is a mixture of magnesium stearate and vinyl bisstearamide in a mass ratio of 2:1; Step S7: adding polyethylene resin, organic flame retardant, antioxidant and lubricant into a high-speed mixer, and then stirring and mixing them at a stirring rate of 450 r / min for 10 min, and then stirring and mixing them at a stirring rate of 1200 r / min for 20 min to obtain a mixed material; Step S8: adding the mixture into a twin-screw extruder, and melt-extrude the mixture at a screw speed of 320 r / min and temperatures of 155° C., 165° C., 175° C., 185° C., and 195° C. from the hopper to the die, respectively. After cooling and pelletizing, a PE-based low-smoke halogen-free flame-retardant cable material is obtained.

[0030] Comparative Example 3: This comparative example is a method for preparing a PE-based low-smoke halogen-free flame-retardant cable material, comprising the following steps: Step S1: 5 g of aluminum hydroxide, 15 mL of deionized water and 80 mL of anhydrous ethanol are added to a three-necked flask equipped with a stirrer, a thermometer and an air duct, and nitrogen is introduced for protection. The mixture is stirred for reaction at a temperature of 30° C. and a stirring rate of 400 r / min for 50 min, and then 3.6 g of γ-glycidyloxypropyltrimethoxysilane is added and the stirring reaction is continued for 15 min. The mixture is then heated to 75° C. and the stirring reaction is continued for 6 h. After the reaction is completed, the reaction product is cooled to room temperature and then centrifuged. The precipitate is washed 3 times with anhydrous methanol, and then placed in a vacuum drying oven and dried at a temperature of 55° C. for 5 h to obtain an inorganic flame retardant. Step S2: 60 parts of polyethylene resin, 11 parts of inorganic flame retardant, 0.6 parts of antioxidant and 2.2 parts of lubricant are weighed in parts by weight for later use; the polyethylene resin is a mixture of high-density polyethylene and linear low-density polyethylene in a mass ratio of 3:2; the antioxidant is a mixture of antioxidant 626 and antioxidant 1010 in a mass ratio of 2:1; the lubricant is a mixture of magnesium stearate and vinyl bisstearamide in a mass ratio of 2:1; Step S3: adding polyethylene resin, inorganic flame retardant, antioxidant and lubricant into a high-speed mixer, and then stirring and mixing them at a stirring rate of 450 r / min for 10 min, and then stirring and mixing them at a stirring rate of 1200 r / min for 20 min to obtain a mixed material; Step S4: adding the mixture into a twin-screw extruder, and melt-extrude the mixture at a screw speed of 320 r / min and temperatures of 155° C., 165° C., 175° C., 185° C., and 195° C. from the hopper to the die, respectively, to obtain a PE-based low-smoke halogen-free flame-retardant cable material after cooling and pelletizing.

[0031] Comparative Example 4: This comparative example is a method for preparing a PE-based low-smoke halogen-free flame-retardant cable material, comprising the following steps: Step S1: weigh 60 parts of polyethylene resin, 18 parts of diethyl phosphite, 11 parts of aluminum hydroxide, 0.6 parts of antioxidant and 2.2 parts of lubricant according to weight parts, and set aside; the polyethylene resin is a mixture of high-density polyethylene and linear low-density polyethylene in a mass ratio of 3:2; the antioxidant is a mixture of antioxidant 626 and antioxidant 1010 in a mass ratio of 2:1; the lubricant is a mixture of magnesium stearate and vinyl bisstearamide in a mass ratio of 2:1; Step S2: adding polyethylene resin, diethyl phosphite, aluminum hydroxide, antioxidant and lubricant into a high-speed mixer, and then stirring and mixing them at a stirring rate of 450 r / min for 10 min, and then stirring and mixing them at a stirring rate of 1200 r / min for 20 min to obtain a mixed material; Step S3: adding the mixture into a twin-screw extruder, and melt-extrude the mixture at a screw speed of 320 r / min and temperatures of 155° C., 165° C., 175° C., 185° C., and 195° C. from the hopper to the die, respectively, to obtain a PE-based low-smoke halogen-free flame-retardant cable material after cooling and pelletizing.

[0032] The PE-based low-smoke halogen-free flame-retardant cable materials of Examples 1-3 and Comparative Examples 1-4 were subjected to performance tests, and the test results are shown in the following table:

[0033] Referring to the data in the above table, based on the comparison between Examples 1-3 and Comparative Examples 1-4, it can be known that the cable material of the present application has an excellent low-smoke flame retardant effect.

[0034] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0035] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the invention or exceed the scope defined in this application, they shall all fall within the protection scope of the present invention.

Claims

1. A PE-based low-smoke halogen-free flame-retardant cable material, characterized in that: It comprises the following components in parts by weight: 50-60 parts of polyethylene resin, 10-18 parts of organic flame retardant, 3-11 parts of inorganic flame retardant, 0.2-0.6 parts of antioxidant and 0.8-2.2 parts of lubricant; Wherein, the organic flame retardant is prepared by the following steps: Step a1: bisphenol A and trifluoroacetic acid are stirred for reaction, and then hexamethylenetetramine is added and the stirring reaction is continued. After the reaction is completed, the reaction product is cooled, and then added to a hydrochloric acid solution and allowed to stand, and then extracted. The extracts are combined and washed and dried, and then vacuum filtered, and the filtrate is rotary evaporated to obtain an intermediate 1; Step a2: Stir the intermediate 1 and anhydrous ethanol for reaction, then add 4-aminophenol and continue stirring for reaction, after the reaction is completed, cool the reaction product, then pour it into ice water, then vacuum filter, and dry the filter cake to obtain the intermediate 2; Step a3: stirring the intermediate 2, diethyl phosphite and anhydrous ethanol to react, cooling the reaction product after the reaction is completed, and then rotary evaporating and recrystallizing to obtain the intermediate 3; Step a4: stirring the intermediate 3, epichlorohydrin, potassium hydroxide and anhydrous ethanol for reaction, then adding potassium hydroxide solution dropwise while stirring, continuing to stir the reaction after the addition is complete, cooling the reaction product after the reaction is complete, then vacuum filtering, rotary evaporating the filtrate, then adding it to dichloromethane, then washing and drying, then vacuum filtering, rotary evaporating the filtrate to obtain intermediate 4; Step a5: Stir the intermediate 4, triphenylphosphine, phenylphosphonic acid and anhydrous acetone for reaction. After the reaction is completed, cool the reaction product, then rotary evaporate and recrystallize to obtain an organic flame retardant.

2. A PE-based low-smoke halogen-free flame-retardant cable material according to claim 1, characterized in that: The usage ratio of bisphenol A, trifluoroacetic acid and hexamethylenetetramine in step a1 is 10 mmol:40-45 mL:100-120 mmol; the mass fraction of the hydrochloric acid solution is 10-15%.

3. A PE-based low-smoke halogen-free flame-retardant cable material according to claim 1, characterized in that: The usage ratio of the intermediate 1, anhydrous ethanol and 4-aminophenol in step a2 is 10 mmol:40-50 mL:22-25 mmol.

4. The PE-based low-smoke halogen-free flame-retardant cable material according to claim 1, characterized in that: The usage ratio of the intermediate 2, diethyl phosphite and anhydrous ethanol in step a3 is 10 mmol: 22-25 mmol: 50-60 mL.

5. The PE-based low-smoke halogen-free flame-retardant cable material according to claim 1, characterized in that: The usage ratio of the intermediate 3, epichlorohydrin, potassium hydroxide, anhydrous ethanol and potassium hydroxide solution in step a4 is 10mmol:60-80mmol:10-15mmol:80-100mL:10-15mL; the mass fraction of the potassium hydroxide solution is 30-40%.

6. The PE-based low-smoke halogen-free flame-retardant cable material according to claim 1, characterized in that: The usage ratio of the intermediate 4, triphenylphosphine, phenylphosphonic acid and anhydrous acetone in step a5 is 10 mmol: 0.3-0.5 g: 50-60 mmol: 100-120 mL.

7. The PE-based low-smoke halogen-free flame-retardant cable material according to claim 1, characterized in that: The inorganic flame retardant is prepared by the following steps: Aluminum hydroxide, deionized water and anhydrous ethanol are stirred for reaction, and then γ-glycidyloxypropyltrimethoxysilane is added and the stirring reaction is continued. After the reaction is completed, the reaction product is cooled and then centrifuged, and the precipitate is washed and dried to obtain an inorganic flame retardant.

8. The PE-based low-smoke halogen-free flame-retardant cable material according to claim 7, characterized in that: The dosage ratio of the aluminum hydroxide, deionized water, anhydrous ethanol and γ-glycidyloxypropyltrimethoxysilane is 5g:10-15mL:70-80mL:1.2-3.6g.

9. A method for preparing a PE-based low-smoke halogen-free flame-retardant cable material, characterized in that: The following steps are involved: Step 1: Weigh 50-60 parts of polyethylene resin, 10-18 parts of organic flame retardant, 3-11 parts of inorganic flame retardant, 0.2-0.6 parts of antioxidant and 0.8-2.2 parts of lubricant according to weight parts, and set aside; Step 2: Add polyethylene resin, organic flame retardant, inorganic flame retardant, antioxidant and lubricant into a high-speed mixer, and then stir and mix at a stirring rate of 350-450 r / min for 8-10 min, and then stir and mix at a stirring rate of 1100-1200 r / min for 15-20 min to obtain a mixed material; Step 3: Add the mixed material into a twin-screw extruder, melt-extrude the mixture at a screw speed of 280-320r / min and at temperatures of 155°C, 165°C, 175°C, 185°C and 195°C from the hopper to the die, and obtain a PE-based low-smoke halogen-free flame-retardant cable material after cooling and pelletizing.

10. The method for preparing a PE-based low-smoke halogen-free flame-retardant cable material according to claim 9, characterized in that: The polyethylene resin is a mixture of high-density polyethylene and linear low-density polyethylene in a mass ratio of 3:2; the antioxidant is a mixture of antioxidant 626 and antioxidant 1010 in a mass ratio of 2:1; and the lubricant is a mixture of magnesium stearate and vinyl bisstearamide in a mass ratio of 2:1.

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