Rare earth flame retardant and production process thereof

Abstract

The invention provides a rare earth flame retardant and a production process thereof. The rare earth flame retardant comprises the following raw materials in parts by weight: 10-20 parts of rare earth nitrate, 10-20 parts of phytic acid, 10-30 parts of a piperazine derivative, 8-15 parts of a carbon nano-composite agent, 10-18 parts of a silicon-magnesium-nitrogen hybrid, 5-12 parts of biomass-based carbon aerogel, 7-13 parts of a boron-nitrogen-phosphorus polymer and 3-7 parts of a metal-organic framework derivative. A cable produced by the rare earth flame retardant does not generate toxic and harmful gas during combustion, the smoke amount is small, under the background that environmental protection laws and regulations tend to be strict, compared with traditional products such as halogen flame retardants, the advantages are obvious, the green development requirement is met, and the higher environmental protection requirement of the market is met.

Description

Technical Field

[0001] The present invention relates to the technical field of flame retardants, and in particular to a rare earth flame retardant and a production process thereof. Background Art

[0002] Throughout human development, fire has always been a major threat to life and property. Its close symbiosis with human activities makes it difficult to completely eliminate, making fire prevention a core component of fire safety efforts. Among the many factors that cause fires, short circuits in wires and cables account for a significant proportion, particularly in densely populated areas such as high-rise buildings and public places. Once such fires occur, they can easily cause serious casualties and property damage. As living standards continue to improve, fire safety and environmental protection measures in these areas are increasingly emphasized. Relevant regulations have established clear and strict regulations for the fire protection ratings and hazardous substance content of buildings and construction materials.

[0003] While traditional flame retardants, such as halogen flame retardants, can achieve a certain degree of flame retardancy, they also release large amounts of toxic and harmful gases during combustion, causing serious environmental pollution and posing a significant threat to the safety of personnel at the fire scene. The application of traditional flame retardants is increasingly restricted, and the market urgently needs new flame retardants that combine high flame retardancy with environmentally friendly properties to meet higher standards of fire safety and environmental protection, and promote the green and sustainable development of the wire and cable industry.

[0004] Against this backdrop, low-smoke, halogen-free, flame-retardant cables emerged. Their original design goal was to effectively prevent the spread of fire in the event of a cable fire through specialized materials and processes, while also reducing the release of toxic fumes during combustion, thereby preventing further damage. However, in actual use, the flame-retardant and environmentally friendly performance of currently available low-smoke, halogen-free cables barely meet the minimum requirements for low smoke and toxicity. Some products even struggle to meet these standards, failing to fully provide effective protection in complex fire scenarios. Summary of the Invention

[0005] In view of the problems existing in the prior art, the present invention provides a rare earth flame retardant and a production process thereof.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions: The present application discloses a rare earth flame retardant, the components of which include the following raw materials in parts by weight: 10-20 parts of rare earth nitrate, 10-20 parts of phytic acid, 10-30 parts of piperazine derivatives, 8-15 parts of carbon nanocomposites, 10-18 parts of silicon magnesium nitrogen hybrids, 5-12 parts of biomass-based carbon aerogels, 7-13 parts of boron nitrogen phosphorus polymers, and 3-7 parts of metal-organic framework derivatives.

[0007] Preferably, the components of the rare earth flame retardant include the following raw materials in parts by weight: 105 parts of rare earth nitrate, 15 parts of phytic acid, 20 parts of piperazine derivatives, 11 parts of carbon nanocomposites, 15 parts of silicon magnesium nitrogen hybrids, 8 parts of biomass-based carbon aerogels, 10 parts of boron nitrogen phosphorus polymers and 5 parts of metal-organic framework derivatives.

[0008] Through the above-mentioned technical solution, rare earth nitrate, as the core active ingredient of the rare earth flame retardant system, its rare earth ions specifically catalyze the carbonization reaction on the material surface at high temperatures, rapidly forming an initial carbon nucleus, laying the foundation for the subsequent construction of a continuous and dense flame-retardant carbon layer. By reducing the rate of free radical generation during combustion, it effectively inhibits flame spread, significantly reduces the combustion velocity and heat release rate, and plays a key catalytic and guiding role in improving flame retardancy. Phytic acid accelerates the carbonization reaction rate, increases the thickness and density of the carbon layer, improves the material's flame retardancy, and stabilizes the reaction process of the flame retardant system during the initial combustion phase. Piperazine derivatives, as nitrogen-containing heterocyclic compounds, decompose upon heating to release large amounts of non-combustible gases such as nitrogen and ammonia, effectively diluting the oxygen concentration in the combustion zone and reducing the combustion efficiency of combustible gases. The nitrogen-containing free radicals produced by their decomposition can also capture active free radicals during the combustion process, terminating the combustion chain reaction. The carbon nanocomposite enhances the stability of the carbon layer, reduces combustion temperature, and reduces smoke generation, significantly improving the overall flame retardancy of the material and optimizing the flame retardant system's protective effect during combustion. Silicon magnesium nitrogen hybrids can effectively block the transfer of free radicals, significantly improve the stability of flame retardants in harsh environments such as high temperature and humidity, prolong the flame retardant effect time, and enhance the environmental adaptability of the flame retardant system. Biomass-based carbon aerogels can reduce the release of combustible gases, improve the physical properties of the carbon layer, enhance the flame retardant properties and structural stability of the material during combustion, and improve the overall flame retardant effect of the material. Boron nitrogen phosphorus polymers can deeply promote carbonization, optimize the carbon layer structure, significantly improve the flame retardant effect and thermal stability of the material, and improve the comprehensive flame retardant properties of the flame retardant system in the condensed phase and gas phase. Metal-organic framework derivatives can promote the graphitization of the carbon layer, enhance the oxidation resistance and strength of the carbon layer, and significantly improve the stability and flame retardant properties of the flame retardant system at high temperatures.

[0009] Preferably, the preparation method of the carbon nanocomposite is as follows: a1. Take graphene oxide and ultrasonically disperse it in deionized water to prepare a 4 mg / mL solution; a2. Add melamine, formaldehyde and boric acid in a mass ratio of 1:3:0.6 to deionized water, and stir at 65°C for 2.5 hours to prepare a prepolymer solution; a3. Slowly pour the graphene oxide solution obtained in a1 into the prepolymer solution, stir and react at 55°C for 5 hours, add ammonia water dropwise to adjust the pH to 8.5, centrifuge, wash with deionized water 4 times, and vacuum dry at 65°C for 15 hours to obtain a carbon nanocomposite.

[0010] By implementing this technical solution, the modified graphene nanosheets, with their excellent mechanical properties and high thermal conductivity, enhance the mechanical strength of the carbon layer, preventing it from cracking at high temperatures while also rapidly dissipating heat to avoid localized overheating. When the melamine-formaldehyde-borate microcapsules are heated, the melamine decomposes to produce non-flammable gases, further diluting the oxygen. The borate decomposes to form a glassy substance that covers the surface of the carbon layer, isolating it from oxygen and heat, enhancing its thermal insulation and antioxidant properties.

[0011] Preferably, the preparation method of the silicon-magnesium-nitrogen hybrid is as follows: add ethyl orthosilicate, magnesium nitrate hexahydrate, and dicyandiamide in a mass ratio of 2:1:3 to an ethanol-water mixed solution with a volume ratio of 4:1, stir evenly, add an appropriate amount of ammonia water to adjust the pH to 8-9, react in a 60°C water bath for 12 hours, and after the reaction is completed, centrifuge the product, wash with ethanol three times, and dry in a vacuum drying oven at 80°C for 24 hours to obtain the silicon-magnesium-nitrogen hybrid.

[0012] By setting up the above technical scheme, the magnesium element in the material generates magnesium oxide during the combustion process, which can efficiently capture free radicals and cut off the combustion chain reaction; the silicon oxide formed by the silicon element can fill the pores of the carbon layer and enhance the thermal and chemical stability of the carbon layer; the nitrogen element decomposes to produce non-combustible gas, which cooperates with other nitrogen-containing components to further dilute the oxygen concentration.

[0013] Preferably, the preparation method of biomass-based carbon aerogel is as follows: the waste sawdust is crushed to 200 mesh, a 20% mass fraction of potassium hydroxide solution is added at a solid-liquid ratio of 1:10 (g / mL), and the mixture is stirred and impregnated at 80°C for 12 hours. The impregnated mixture is transferred to a tubular furnace, and under argon protection, the temperature is increased to 800°C at 5°C / min, kept warm for 3 hours, cooled, and repeatedly washed with deionized water until neutral, and then replaced with ethanol and supercritically dried to obtain biomass-based carbon aerogel.

[0014] By setting up the above technical scheme, the unique three-dimensional porous structure of biomass-based carbon aerogel can increase the specific surface area of ​​the carbon layer, adsorb the heat and small molecular combustible gases generated by combustion, reduce the temperature of the combustion system, and at the same time serve as the skeleton for the growth of the carbon layer, enhance the integrity and anti-destruction ability of the carbon layer, and improve the strength and toughness of the carbon layer.

[0015] Preferably, the preparation method of the boron nitrogen phosphate polymer is as follows: boric acid, melamine, and phosphorus oxychloride are added to dichloromethane in a mass ratio of 1:1.2:1.3, and 5% of the total mass of pyridine catalyst is added. The reaction is refluxed at 70°C for 15 hours. After the reaction is completed, the reaction is cooled to room temperature, and the pyridine hydrochloride precipitate is removed by filtration. The filtrate is subjected to rotary evaporation to remove dichloromethane, and then recrystallized with acetone and dried in a vacuum drying oven at 55°C for 12 hours to obtain a boron nitrogen phosphate polymer.

[0016] By setting up the above technical scheme, the polyphosphoric acid produced by the decomposition of the boron-nitrogen-phosphorus polymer works synergistically with the decomposition products of phytic acid to further promote the carbonization process and accelerate the formation and growth of the carbon layer. The borate glassy substance formed by the boron element covers the surface of the carbon layer, enhancing the thermal insulation and antioxidant properties of the carbon layer; the nitrogen element decomposes to produce non-combustible gas, which works synergistically with other nitrogen-containing components to exert a gas-phase flame retardant effect.

[0017] Preferably, the preparation method of the metal-organic framework derivative is as follows: cobalt nitrate and terephthalic acid are added to a mixed solution of N,N-dimethylformamide-water with a volume ratio of 4:1 in a mass ratio of 1:2, and reacted at 120°C for 24 hours to obtain a cobalt-terephthalate metal-organic framework, and the cobalt-terephthalate metal-organic framework is placed in a tube furnace, and under argon protection, the temperature is increased to 700°C at 4°C / min, kept warm for 4 hours, and cooled to obtain a metal-organic framework derivative.

[0018] By setting up the above-mentioned technical scheme, the carbides and metal oxides produced by the pyrolysis of metal-organic framework derivatives can promote the graphitization of the carbon layer, improve the oxidation resistance and strength of the carbon layer. Under high temperature conditions, the special structure formed can effectively block the transfer of heat and oxygen, further enhancing the flame retardant effect. It is especially suitable for cable application scenarios that have to withstand high temperature environments for a long time.

[0019] This application also discloses a production process of a rare earth flame retardant, comprising the following steps: S1. Preparation of Solution A: Add rare earth nitrate and deionized water in a ratio of 10 mmol-50 mmol: 10 mL-50 mL into a reaction kettle, dissolve at 30-40 ° C and stirring at 200-300 r / min, and continue stirring for 30-40 min to obtain Solution A; S2. Solution B preparation: add phytic acid to deionized water, controlling the mass ratio of phytic acid to deionized water to be 1:5-10, and stir at 25-35°C and 150-250 rpm for 20-30 min to obtain Solution B; S3. Preparation of Solution C: Add the piperazine derivative to Solution B, stirring at 30-40° C. and 200-300 rpm for 30-40 min according to a ratio of 1 mmol-5 mmol of piperazine derivative to 10 mL-50 mL of deionized water to obtain Solution C. S4. Mixing and dispersion: sequentially add the carbon nanocomposite, silicon magnesium nitrogen hybrid, biomass-based carbon aerogel, boron nitrogen phosphorus polymer, and metal-organic framework derivative to solution C, raise the temperature to 50-60°C, and stir thoroughly to fully disperse and mix the components; S5, reaction curing: heat the S4 mixture to 80-90°C, and stir at a speed of 150-200 r / min for 3-4 hours under a nitrogen atmosphere to promote chemical reaction between the components and form a stable flame retardant system; S6. Post-treatment: After the reaction in S5 is completed, the system is cooled to room temperature, concentrated under reduced pressure under vacuum conditions to remove 70-80% of the water, and the concentrated product is spray-dried, with the inlet temperature controlled at 180-200°C and the outlet temperature at 80-90°C. The product is sieved through a 500-600 mesh sieve to obtain a rare earth flame retardant.

[0020] Preferably, in step S4, stirring is performed at a speed of 300-400 r / min for 60-90 min.

[0021] Preferably, in step S5, the vacuum pressure of the reduced pressure concentration is -0.09 to -0.08 MPa.

[0022] The beneficial effects of the present invention are: Rare earth flame retardants can significantly improve the flame retardant effect of materials, reduce the burning speed and heat release rate, and when added to the plastic sheath of wires and cables, they can effectively prevent fires caused by cable combustion due to short circuits, etc. The new rare earth flame retardant has a good synergistic effect with other flame retardants, can enhance the performance of traditional flame retardants, reduce their dosage, reduce costs and improve the flame retardant effect. Its application in cable insulation sheaths can reduce the amount of other flame retardants added. The rare earth flame retardant obtained by the present invention has good thermal stability and hydrolysis resistance, and its performance is stable in high temperature and humid environments, which is beneficial for fields susceptible to environmental influences such as outdoor laying of cables. The cables produced by the flame retardant obtained by the present invention do not produce toxic or harmful gases when burned, and the amount of smoke is small. In the context of stricter environmental protection regulations, it has obvious advantages over traditional products such as halogen flame retardants, meets the requirements of green development, and meets the market's higher environmental protection needs.

[0023] Rare earth nitrate can rapidly form a heat-insulating and oxygen-isolating char layer on the material's surface, significantly reducing the combustion system temperature, slowing the combustion process, and significantly enhancing the material's flame retardancy. Piperazine derivatives inhibit the combustion reaction through a dual mechanism of gas-phase dilution and free radical capture, slowing flame propagation and buying time to prevent the spread of fire. Carbon nanocomposites can enhance char layer stability, lower combustion temperatures, and reduce smoke production, significantly improving the material's overall flame retardancy and optimizing the flame retardant system's effectiveness during combustion. Silicon-magnesium-nitrogen hybrids can effectively block free radical propagation, significantly enhancing the stability of flame retardants in harsh environments such as high temperature and humidity, prolonging the flame retardant effect and strengthening the flame retardant system's environmental adaptability. Biomass-based carbon aerogels can reduce combustible gas release, improve the physical properties of the char layer, enhance the material's flame retardancy and structural stability during combustion, and improve the material's overall flame retardancy. Boron-nitrogen-phosphorus polymers can deeply promote carbonization, optimize the char layer structure, significantly enhance the flame retardancy and thermal stability of the material, and improve the flame retardancy of the flame retardant system in both the condensed and gas phases. Metal-organic framework derivatives can promote the graphitization of the carbon layer, enhance the oxidation resistance and strength of the carbon layer, and significantly improve the stability and flame retardant properties of the flame retardant system at high temperatures.

[0024] The present invention constructs a three-dimensional synergistic flame retardant mechanism of "multi-component carbon layer reinforcement-gas-solid two-phase synergy-environmental adaptability optimization". Starting from different stages of combustion, different levels of gas phase and condensed phase, and different environmental adaptability requirements, each component cooperates with each other to form a complex and efficient synergistic network. In terms of carbon layer construction, multiple components work synergistically from carbon core formation to structural optimization. In terms of flame retardant methods, an organic combination of gas phase flame retardancy and condensed phase flame retardancy is achieved. In terms of environmental adaptability, stability is synergistically improved in high temperature, humid and other environments. This synergistic mechanism breaks through the single or simple combination mode of traditional flame retardant technology, produces excellent flame retardant effects and comprehensive performance improvements that far exceed expectations, and brings unexpected technical effects. DETAILED DESCRIPTION

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with 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. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0026] Example 1: This example discloses a rare earth flame retardant, the components of which include the following raw materials in parts by weight: 10 parts of rare earth nitrate, 10 parts of phytic acid, 10 parts of piperazine derivatives, 8 parts of carbon nanocomposites, 10 parts of silicon magnesium nitrogen hybrids, 5 parts of biomass-based carbon aerogels, 7 parts of boron nitrogen phosphorus polymers and 3 parts of metal-organic framework derivatives.

[0027] The preparation method of the carbon nanocomposite is as follows: a1. Take graphene oxide and ultrasonically disperse it in deionized water to prepare a 4 mg / mL solution; a2. Add melamine, formaldehyde and boric acid in a mass ratio of 1:3:0.6 to deionized water, and stir at 65°C for 2.5 hours to prepare a prepolymer solution; a3. Slowly pour the graphene oxide solution obtained in a1 into the prepolymer solution, stir and react at 55°C for 5 hours, add ammonia water dropwise to adjust the pH to 8.5, centrifuge, wash with deionized water 4 times, and vacuum dry at 65°C for 15 hours to obtain a carbon nanocomposite.

[0028] The preparation method of silicon-magnesium-nitrogen hybrid is as follows: add ethyl orthosilicate, magnesium nitrate hexahydrate, and dicyandiamide in a mass ratio of 2:1:3 to an ethanol-water mixed solution with a volume ratio of 4:1, stir evenly, add an appropriate amount of ammonia water to adjust the pH to 8-9, react in a 60°C water bath for 12 hours, and after the reaction is completed, centrifuge the product, wash with ethanol three times, and dry in a vacuum drying oven at 80°C for 24 hours to obtain silicon-magnesium-nitrogen hybrid.

[0029] The preparation method of biomass-based carbon aerogel is as follows: waste sawdust is crushed to 200 mesh, and a 20% mass fraction of potassium hydroxide solution is added at a solid-liquid ratio of 1:10 (g / mL). The mixture is stirred and impregnated at 80°C for 12 hours. The impregnated mixture is transferred to a tubular furnace, and under argon protection, the temperature is increased to 800°C at 5°C / min, and kept warm for 3 hours. After cooling, it is repeatedly washed with deionized water until neutral, and then replaced with ethanol and supercritically dried to obtain biomass-based carbon aerogel.

[0030] The preparation method of the boron nitrogen phosphate polymer is as follows: boric acid, melamine, and phosphorus oxychloride are added to dichloromethane in a mass ratio of 1:1.2:1.3, and a pyridine catalyst is added at a total mass ratio of 5%. The reaction is refluxed at 70°C for 15 hours. After the reaction is completed, the mixture is cooled to room temperature, and the pyridine hydrochloride precipitate is removed by filtration. The filtrate is subjected to rotary evaporation to remove dichloromethane, and then recrystallized with acetone and dried in a vacuum drying oven at 55°C for 12 hours to obtain the boron nitrogen phosphate polymer.

[0031] The preparation method of the metal-organic framework derivative is as follows: cobalt nitrate and terephthalic acid are added to a mixed solution of N,N-dimethylformamide and water with a volume ratio of 4:1 in a mass ratio of 1:2, and the mixture is reacted at 120°C for 24 hours to obtain a cobalt-terephthalic acid metal-organic framework. The cobalt-terephthalic acid metal-organic framework is placed in a tubular furnace, and under argon protection, the temperature is increased to 700°C at 4°C / min, kept warm for 4 hours, and cooled to obtain a metal-organic framework derivative.

[0032] This embodiment also discloses a production process of a rare earth flame retardant, comprising the following steps: S1. Preparation of Solution A: Add rare earth nitrate and deionized water in a ratio of 10 mmol:10 mL into a reaction kettle, dissolve at 30°C and stirring at 200 r / min, and continue stirring for 30 min to obtain Solution A; S2. Solution B preparation: add phytic acid to deionized water, controlling the mass ratio of phytic acid to deionized water to be 1:5, and stir at 25°C and 150 r / min for 20 min to obtain Solution B; S3. Preparation of Solution C: Add the piperazine derivative to Solution B, stirring at 30°C and 200 rpm for 30 min according to a ratio of 1 mmol of piperazine derivative to 10 mL of deionized water to obtain Solution C. S4. Mixing and dispersion: Add the carbon nanocomposite, silicon magnesium nitrogen hybrid, biomass-based carbon aerogel, boron nitrogen phosphorus polymer, and metal-organic framework derivative to solution C in sequence, raise the temperature to 50°C, and stir at a speed of 300 r / min for 60 min to fully disperse and mix the components; S5, reaction curing: the S4 mixture was heated to 80°C and stirred at a speed of 150 r / min for 3 hours under a nitrogen atmosphere to promote chemical reactions between the components and form a stable flame retardant system; S6. Post-treatment: After the reaction in S5 is completed, the system is cooled to room temperature, concentrated under reduced pressure at -0.09 MPa to remove 70% of the water, and the concentrated product is spray-dried with the inlet temperature controlled at 180°C and the outlet temperature controlled at 80°C. The product is sieved through a 500-mesh sieve to obtain a rare earth flame retardant.

[0033] Example 2: This example discloses a rare earth flame retardant, the components of which include the following raw materials in parts by weight: 20 parts of rare earth nitrate, 20 parts of phytic acid, 30 parts of piperazine derivatives, 15 parts of carbon nanocomposites, 18 parts of silicon magnesium nitrogen hybrids, 12 parts of biomass-based carbon aerogels, 13 parts of boron nitrogen phosphorus polymers and 7 parts of metal-organic framework derivatives.

[0034] The preparation methods of the carbon nanocomposite, the silicon magnesium nitrogen hybrid, the biomass-based carbon aerogel, the boron nitrogen phosphorus polymer, and the metal-organic framework derivative are all the same as those in Example 1.

[0035] This embodiment also discloses a production process of a rare earth flame retardant, comprising the following steps: S1. Preparation of Solution A: Add rare earth nitrate and deionized water in a ratio of 50 mmol:50 mL into a reaction kettle, dissolve at 40°C and stirring at 300 r / min, and continue stirring for 40 min to obtain Solution A; S2. Solution B preparation: add phytic acid to deionized water, controlling the mass ratio of phytic acid to deionized water to be 1:10, and stir at 35°C and 250 r / min for 30 min to obtain Solution B; S3. Preparation of Solution C: Add the piperazine derivative to Solution B, stir at 40°C and 300 rpm for 40 min according to the ratio of 5 mmol of piperazine derivative to 50 mL of deionized water, to obtain Solution C; S4. Mixing and dispersion: Add the carbon nanocomposite, silicon magnesium nitrogen hybrid, biomass-based carbon aerogel, boron nitrogen phosphorus polymer, and metal-organic framework derivative to solution C in sequence, raise the temperature to 60°C, and stir at 400 rpm for 90 min to fully disperse and mix the components; S5, reaction curing: the S4 mixture was heated to 90°C and stirred at a speed of 200 r / min for 4 hours under a nitrogen atmosphere to promote chemical reactions between the components and form a stable flame retardant system; S6. Post-treatment: After the reaction in S5 is completed, the system is cooled to room temperature, concentrated under reduced pressure at -0.08 MPa to remove 80% of the water, and the concentrated product is spray-dried with the inlet temperature controlled at 200°C and the outlet temperature controlled at 90°C. The product is sieved through a 600-mesh sieve to obtain a rare earth flame retardant.

[0036] Example 3: This example discloses a rare earth flame retardant, the components of which include the following raw materials in parts by weight: 105 parts of rare earth nitrate, 15 parts of phytic acid, 20 parts of piperazine derivatives, 11 parts of carbon nanocomposites, 15 parts of silicon magnesium nitrogen hybrids, 8 parts of biomass-based carbon aerogels, 10 parts of boron nitrogen phosphorus polymers and 5 parts of metal-organic framework derivatives.

[0037] The preparation methods of the carbon nanocomposite, the silicon magnesium nitrogen hybrid, the biomass-based carbon aerogel, the boron nitrogen phosphorus polymer, and the metal-organic framework derivative are all the same as those in Example 1.

[0038] This embodiment also discloses a production process of a rare earth flame retardant, comprising the following steps: S1. Preparation of Solution A: Add rare earth nitrate and deionized water in a ratio of 30 mmol:30 mL into a reaction kettle, dissolve at 35°C and stirring at 250 r / min, and continue stirring for 35 min to obtain Solution A; S2. Solution B preparation: add phytic acid to deionized water, controlling the mass ratio of phytic acid to deionized water to be 1:7, and stir at 30°C and 200 r / min for 25 min to obtain Solution B; S3. Preparation of Solution C: Add the piperazine derivative to Solution B, and stir at 35°C and 250 rpm for 35 min according to the ratio of 3 mmol of piperazine derivative to 30 mL of deionized water to obtain Solution C. S4. Mixing and dispersion: Add the carbon nanocomposite, silicon magnesium nitrogen hybrid, biomass-based carbon aerogel, boron nitrogen phosphorus polymer, and metal-organic framework derivative to solution C in sequence, raise the temperature to 55°C, and stir at a speed of 350 r / min for 75 minutes to fully disperse and mix the components; S5, reaction curing: the S4 mixture was heated to 85°C and stirred at a speed of 175 r / min for 3.5 h under a nitrogen atmosphere to promote chemical reaction between the components and form a stable flame retardant system; S6. Post-treatment: After the reaction in S5 is completed, the system is cooled to room temperature, concentrated under reduced pressure at -0.085 MPa to remove 75% of the water, and the concentrated product is spray-dried while controlling the inlet temperature at 190°C and the outlet temperature at 85°C. The product is passed through a 550-mesh sieve to obtain a rare earth flame retardant.

[0039] Comparative Example 1: A flame retardant. The only difference between this flame retardant and Example 3 is that rare earth nitrate is not added, and the rare earth nitrate in the formula is increased in proportion to the components until the total component weight is equal to that of the total component weight of Example 3.

[0040] Comparative Example 2: A rare earth flame retardant. The only difference between this rare earth flame retardant and Example 3 is that phytic acid is not added, and the phytic acid in the formula is increased in proportion to the components until the total weight of the components is equal to that of the total weight of the components in Example 3.

[0041] Comparative Example 3: A rare earth flame retardant. The only difference between this rare earth flame retardant and Example 3 is that no piperazine derivative is added, and the piperazine derivative in the formula is increased in equal proportion to the components until the total component weight is equal to that of Example 3.

[0042] Comparative Example 4: A rare earth flame retardant. The only difference between this rare earth flame retardant and Example 3 is that no carbon nanocomposite is added, and the carbon nanocomposite is increased in proportion to the components in the formula until the total component weight is equal to that of the total component weight of Example 3.

[0043] Comparative Example 5: A rare earth flame retardant. The only difference between this rare earth flame retardant and Example 3 is that silicon magnesium nitrogen hybrid is not added, and its content in the formula is increased in equal proportion to the components until the total weight of the components is equal to that of Example 3.

[0044] Comparative Example 6: A rare earth flame retardant. The only difference between this rare earth flame retardant and Example 3 is that no biomass-based carbon aerogel is added, and the aerogel in the formula is increased in proportion to the components until the total component weight is equal to that of Example 3.

[0045] Comparative Example 7: A rare earth flame retardant. The only difference between this rare earth flame retardant and Example 3 is that no boron nitrogen phosphorus polymer is added, and the boron nitrogen phosphorus polymer in the formula is increased in proportion to the components until the total component weight is equal to that of the total component weight of Example 3.

[0046] Comparative Example 8: A rare earth flame retardant. The only difference between this rare earth flame retardant and Example 3 is that no metal-organic framework derivative is added, and the metal-organic framework derivative in the formula is increased in proportion to the components until the total component weight is equal to that of the total component weight of Example 3.

[0047] The flame retardants obtained in Examples 1-3 and Comparative Examples 1-8, as well as halogen flame retardants in the prior art, were respectively applied to cable formulations (the components and contents in the cable formulations were the same, the only difference being the flame retardants), and single vertical burning test, bundle burning test, smoke density test, halogen acid gas release test, and toxicity index test were conducted. The test criteria are as follows: Single vertical burning test: The test is conducted in accordance with GB / T 18380.12-2008 "Electric and optical cables - Fire tests under flame conditions - Part 12: Single insulated wire and cable - Vertical flame spread test - 1kW premixed flame test method". The prepared cable sample containing flame retardant is fixed vertically, the specified flame is applied, the flame spread is observed, and the distance D between the lower edge of the fixture and the upper carbonization starting point is recorded.

[0048] Bundle combustion test: This test is conducted in accordance with GB / T 18380.33-2008, "Electrical and optical cables – Fire tests under fire conditions – Part 33: Bundled wire and cable – Vertical flame spread test, Category A." Multiple cable specimens are bundled together and subjected to a combustion test to assess the extent of flame spread.

[0049] Smoke density test: The test is conducted in accordance with GB / T 8323.2-2008, "Plastics - Smoke Generation - Part 2: Single Chamber Test Method for Determination of Smoke Density." Under specified combustion conditions, the light transmittance of the smoke generated during combustion is measured.

[0050] Halogen acid gas release test: This test is conducted in accordance with GB / T 17650.2-1998, "Test methods for gases evolved during combustion of materials from electrical or optical cables - Part 2: Determination of gas acidity by pH and conductivity." The gases released during combustion are collected, their pH and conductivity are measured, and the halogen acid gas release is calculated.

[0051] Toxicity index test: Refer to ISO 13579-1999 "Fire tests - Toxicity hazards - Part 1: General principles" to determine the toxicity of combustion products through animal experiments or simulated human exposure environments.

[0052] The comprehensive properties of the rare earth flame retardants obtained in the examples and comparative examples were measured, and the results are shown in Table 1.

[0053] Table 1 Performance parameters of rare earth flame retardants obtained in Examples 1-3 and Comparative Examples 1-8

[0054] From Table 1 we can see that: In the formula of the rare earth flame retardant obtained by the present invention, the addition of each component has a significant impact on the distance between the lower edge of the clamp and the upper carbonization starting point when the flame retardant component is applied to the cable and then burned, whether the bundled cable passes the Class A standard, and the light transmittance of the cable after burning, and the performance of each group is significantly better than the halogen flame retardant in the prior art.

[0055] The rare earth flame retardant obtained by the present invention meets the performance requirements of the cable industry for cable flame retardants: the distance between the lower edge of the upper clamp and the upper carbonization starting point is greater than 450 mm, the bundle combustion passes the A standard category; the smoke density (during combustion) transmittance is greater than or equal to 60%, the halogen acid gas release amount is less than or equal to 2 mg / g, and the toxicity index CIT is less than or equal to 5.

[0056] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A rare earth flame retardant, characterized in that: The rare earth flame retardant comprises the following raw materials in parts by weight: 10-20 parts of rare earth nitrate, 10-20 parts of phytic acid, 10-30 parts of piperazine derivatives, 8-15 parts of carbon nanocomposites, 10-18 parts of silicon magnesium nitrogen hybrids, 5-12 parts of biomass-based carbon aerogels, 7-13 parts of boron nitrogen phosphorus polymers and 3-7 parts of metal-organic framework derivatives.

2. The rare earth flame retardant according to claim 1, characterized in that The rare earth flame retardant comprises the following raw materials in parts by weight: 105 parts of rare earth nitrate, 15 parts of phytic acid, 20 parts of piperazine derivatives, 11 parts of carbon nanocomposites, 15 parts of silicon magnesium nitrogen hybrids, 8 parts of biomass-based carbon aerogels, 10 parts of boron nitrogen phosphorus polymers and 5 parts of metal-organic framework derivatives.

3. The rare earth flame retardant according to claim 1 or 2, characterized in that The preparation method of the carbon nanocomposite is as follows: a1. Take graphene oxide and ultrasonically disperse it in deionized water to prepare a 4 mg / mL solution; a2. Add melamine, formaldehyde and boric acid in a mass ratio of 1:3:0.6 to deionized water, and stir at 65°C for 2.5 hours to prepare a prepolymer solution; a3. Slowly pour the graphene oxide solution obtained in a1 into the prepolymer solution, stir and react at 55°C for 5 hours, add ammonia water dropwise to adjust the pH to 8.5, centrifuge, wash with deionized water 4 times, and vacuum dry at 65°C for 15 hours to obtain a carbon nanocomposite.

4. The rare earth flame retardant according to claim 1 or 2, characterized in that The preparation method of silicon-magnesium-nitrogen hybrid is as follows: add ethyl orthosilicate, magnesium nitrate hexahydrate, and dicyandiamide in a mass ratio of 2:1:3 to an ethanol-water mixed solution with a volume ratio of 4:1, stir evenly, add an appropriate amount of ammonia water to adjust the pH to 8-9, react in a 60°C water bath for 12 hours, and after the reaction is completed, centrifuge the product, wash with ethanol three times, and dry in a vacuum drying oven at 80°C for 24 hours to obtain silicon-magnesium-nitrogen hybrid.

5. The rare earth flame retardant according to claim 1 or 2, characterized in that: The preparation method of biomass-based carbon aerogel is as follows: waste sawdust is crushed to 200 mesh, and a 20% mass fraction of potassium hydroxide solution is added at a solid-liquid ratio of 1:10 (g / mL). The mixture is stirred and impregnated at 80°C for 12 hours. The impregnated mixture is transferred to a tubular furnace, and under argon protection, the temperature is increased to 800°C at 5°C / min, and kept warm for 3 hours. After cooling, it is repeatedly washed with deionized water until neutral, and then replaced with ethanol and supercritically dried to obtain biomass-based carbon aerogel.

6. The rare earth flame retardant according to claim 1 or 2, characterized in that: The preparation method of the boron nitrogen phosphate polymer is as follows: boric acid, melamine, and phosphorus oxychloride are added to dichloromethane in a mass ratio of 1:1.2:1.3, and a pyridine catalyst is added at a total mass ratio of 5%. The reaction is refluxed at 70°C for 15 hours. After the reaction is completed, the mixture is cooled to room temperature, and the pyridine hydrochloride precipitate is removed by filtration. The filtrate is subjected to rotary evaporation to remove dichloromethane, and then recrystallized with acetone and dried in a vacuum drying oven at 55°C for 12 hours to obtain the boron nitrogen phosphate polymer.

7. The rare earth flame retardant according to claim 1 or 2, characterized in that: The preparation method of the metal-organic framework derivative is as follows: cobalt nitrate and terephthalic acid are added to a mixed solution of N,N-dimethylformamide and water with a volume ratio of 4:1 in a mass ratio of 1:2, and the mixture is reacted at 120°C for 24 hours to obtain a cobalt-terephthalic acid metal-organic framework. The cobalt-terephthalic acid metal-organic framework is placed in a tubular furnace, and under argon protection, the temperature is increased to 700°C at 4°C / min, kept warm for 4 hours, and cooled to obtain a metal-organic framework derivative.

8. A production process of a rare earth flame retardant according to any one of claims 1 to 7, characterized in that: The steps are as follows: S1. Preparation of Solution A: Add rare earth nitrate and deionized water in a ratio of 10 mmol-50 mmol: 10 mL-50 mL into a reaction kettle, dissolve at 30-40 ° C and stirring at 200-300 r / min, and continue stirring for 30-40 min to obtain Solution A; S2. Solution B preparation: add phytic acid to deionized water, controlling the mass ratio of phytic acid to deionized water to be 1:5-10, and stir at 25-35°C and 150-250 rpm for 20-30 min to obtain Solution B; S3. Preparation of Solution C: Add the piperazine derivative to Solution B, stirring at 30-40° C. and 200-300 rpm for 30-40 min according to a ratio of 1 mmol-5 mmol of piperazine derivative to 10 mL-50 mL of deionized water to obtain Solution C. S4. Mixing and dispersion: sequentially add the carbon nanocomposite, silicon magnesium nitrogen hybrid, biomass-based carbon aerogel, boron nitrogen phosphorus polymer, and metal-organic framework derivative to solution C, raise the temperature to 50-60°C, and stir thoroughly to fully disperse and mix the components; S5, reaction curing: heat the S4 mixture to 80-90°C, and stir at a speed of 150-200 r / min for 3-4 hours under a nitrogen atmosphere to promote chemical reaction between the components and form a stable flame retardant system; S6. Post-treatment: After the reaction in S5 is completed, the system is cooled to room temperature, concentrated under reduced pressure under vacuum conditions to remove 70-80% of the water, and the concentrated product is spray-dried, with the inlet temperature controlled at 180-200°C and the outlet temperature at 80-90°C. The product is sieved through a 500-600 mesh sieve to obtain a rare earth flame retardant.

9. The production process of rare earth flame retardant according to claim 8, characterized in that: In step S4, stirring is performed at a speed of 300-400 r / min for 60-90 min.

10. The production process of rare earth flame retardant according to claim 8, characterized in that: In step S5, the vacuum pressure of the reduced pressure concentration is -0.09 to -0.08 MPa.

Images