Graphene heating base cloth and preparation process thereof

Abstract

The invention relates to the technical field of heating materials, in particular to graphene heating base cloth and a preparation process thereof. The preparation method comprises the following steps: mixing a dispersing agent, an acrylic acid binder, a modified carbon nanotube, an aromatic microcapsule and a solvent to obtain a mixed solution; mixing graphene and a solvent, uniformly dispersing, and adding into the mixed solution, so as to obtain a graphene dispersion solution; and coating the surface of the base cloth with the graphene dispersion liquid to obtain the graphene heating base cloth. The graphene heating base cloth prepared by the invention has excellent thermal performance, flame retardance and aging resistance, so that the graphene heating base cloth has a wide application prospect in the technical field of heating materials.

Description

Technical Field

[0001] This invention relates to the field of heating materials technology, specifically a graphene heating substrate and its preparation process. Background Technology

[0002] Graphene heating substrate is an innovative application of graphene materials in the field of thermal management. Its core value stems from graphene's unique two-dimensional honeycomb crystal structure, which endows it with excellent electrical and thermal conductivity. Compared with traditional solutions relying on metal heating wires or carbon fibers, graphene heating substrate can achieve rapid and uniform planar heating at low operating voltages, exhibiting higher electrothermal conversion efficiency and lower energy consumption. This better meets the urgent needs of modern consumer electronics, medical therapy, and special clothing for precise, safe, and comfortable heat sources. For graphene heating substrate, heating performance is a direct manifestation of product functionality. Improving electrothermal conversion efficiency means achieving the same temperature rise with lower energy consumption, which will effectively enhance the product's market competitiveness. Therefore, improving the heating performance of graphene heating substrate is an inevitable requirement for its transition from laboratory concept to large-scale, highly reliable commercial applications.

[0003] Furthermore, as graphene heating fabric is a product that frequently comes into contact with the human body, flame retardancy is crucial to its safety. The heating element itself must possess flame-retardant or even non-combustible properties to prevent or delay the generation and spread of open flames, thus preventing catastrophic accidents. Moreover, under long-term thermal cycling, changes in environmental temperature and humidity, and mechanical stress (such as bending), the conductive heating network of the heating fabric may degrade due to material oxidation, structural fatigue, and interface delamination. Therefore, it is essential to improve its anti-aging properties to ensure that its resistance stability and heating uniformity do not significantly deteriorate over a long period.

[0004] To overcome the shortcomings of the prior art, the present invention provides a graphene heating substrate and its preparation process. Summary of the Invention

[0005] The purpose of this invention is to provide a graphene heating substrate and its preparation process to solve the problems raised in the prior art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A process for preparing a graphene heating substrate includes the following steps: A dispersant, acrylic binder, modified carbon nanotubes, aromatic microencapsulation agent, and solvent are mixed and dispersed evenly to obtain a mixture. Graphene and solvent are mixed, ultrasonically dispersed evenly, and then added to the mixture to obtain a graphene dispersion. The graphene dispersion is evenly coated onto the surface of a base fabric to obtain a graphene heating base fabric. The modified carbon nanotubes are obtained by grafting isophorone diisocyanate with hydroxylated flame retardant and antioxidant 2,6-di-tert-butyl-4-hydroxymethylphenol, followed by further modification of the carbon nanotubes; the acrylic antioxidant is introduced into the acrylic monomer and polymerized under the action of an initiator to obtain the acrylic adhesive.

[0007] More preferably, the solvent is N-methylpyrrolidone; the dispersant is polyvinylpyrrolidone; and the content of each component in the graphene dispersion is as follows (by mass): 1.5-3.0 parts dispersant, 6-8 parts acrylic binder, 3-5 parts modified carbon nanotubes, 0.8-1.0 parts aromatic microencapsulation agent, 70-80 parts solvent, and 8-12 parts graphene.

[0008] A more optimized preparation process for modified carbon nanotubes is as follows: Step S1: Mix anhydrous acetonitrile and phenylphosphonic dichloro evenly to obtain a reaction solution; under a nitrogen atmosphere, mix anhydrous acetonitrile and m-phenylenediamine, then add triethylamine and cool to 0-2℃, then add the reaction solution dropwise. After the dropwise addition is complete, continue the reaction for 2.5-3.0h, then heat to 20-25℃ and continue the reaction for 10-15h. After the reaction is complete, filter, rotary evaporate, precipitate, wash and dry to obtain an aminoated flame retardant. Step S2: Mix vanillin and anhydrous ethanol to obtain a vanillin solution; under a nitrogen atmosphere, mix the aminated flame retardant and anhydrous ethanol, then add the vanillin solution dropwise. After the addition is complete, heat to 50-55℃ and react for 5.5-6.0 h. After the reaction is complete, rotary evaporate to obtain a hydroxylated flame retardant; mix the hydroxylated flame retardant and N,N-dimethylformamide to obtain a flame retardant reaction solution. Step S3: Mix 2,6-di-tert-butyl-4-hydroxymethylphenol and N,N-dimethylformamide to obtain an antioxidant reaction solution; mix hydroxylated carbon nanotubes and N,N-dimethylformamide and ultrasonically disperse to obtain a hydroxylated carbon nanotube dispersion; under a nitrogen atmosphere, mix isophorone diisocyanate, dibutyltin dilaurate, and N,N-dimethylformamide, and add the flame retardant reaction solution and antioxidant reaction solution dropwise at 27-30℃. After the addition is complete, continue the reaction for 7-9 hours, then add the hydroxylated carbon nanotube dispersion, raise the temperature to 70-75℃ and continue the reaction for 8-10 hours. After the reaction is complete, centrifuge, wash, and dry to obtain modified carbon nanotubes.

[0009] In a more optimized manner, in step S1, the molar ratio of phenylphosphonic dichloride to m-phenylenediamine is 1:(2.1-2.2).

[0010] In a more optimized manner, in step S2, the reaction molar ratio of the aminated flame retardant to vanillin is 1:(2.1-2.2).

[0011] In a more optimized manner, in step S3, the reaction mass ratio of isophorone diisocyanate, 2,6-di-tert-butyl-4-hydroxymethylphenol, hydroxylated flame retardant, and hydroxylated carbon nanotubes is (5-7):1:(3.5-5.4):(0.8-1.0).

[0012] A more optimized preparation process for acrylic adhesives is as follows: Step 1: Glycidyl methacrylate, 2,2,4-trimethyl-1,2-dihydroquinoline, and toluene solvent are mixed and reacted at 90-100℃ for 5-6 hours. During the reaction, the polymerization inhibitor 4-methoxyphenol is added intermittently. After the reaction is completed, the mixture is rotary evaporated, washed, and dried to obtain the propylene antioxidant. Butyl acrylate, methyl methacrylate, the propylene antioxidant, and acrylic acid are mixed to obtain an oily solution. Step 2: Mix the emulsifier alkylphenol polyoxyethylene ether, the emulsifier allyloxynonylphenol polyoxyethylene ether ammonium sulfate, and deionized water. Stir evenly at 85-90℃, then add the initiator. Add the aqueous solution, oil solution, and initiator dropwise. After the dropwise addition is complete, keep warm for 25-35 minutes, then cool down to 25-30℃ and adjust the pH of the solution to neutral to obtain the acrylic adhesive.

[0013] In a more optimized manner, in step 1, the molar ratio of glycidyl methacrylate to 2,2,4-trimethyl-1,2-dihydroquinoline is (1.05-1.10):1.

[0014] In a more optimized manner, in step 2, 20-25 parts of acrylamide, 3-5 parts of N,N-methylenebisacrylamide, and 25-30 parts of deionized water are mixed to obtain an aqueous solution; 40-50 parts of butyl acrylate, 15-20 parts of methyl methacrylate, 8-12 parts of propylene antioxidant, and 2-3 parts of acrylic acid are mixed to obtain an oil-based solution; 0.5-0.7 parts of ammonium persulfate, 0.3-0.4 parts of sodium bicarbonate, and 2-3 parts of deionized water are mixed to obtain an initiator; the content of each component of the acrylic adhesive is as follows (by mass): 2-3 parts of alkylphenol polyoxyethylene ether, 2-3 parts of allyloxynonylphenol polyoxyethylene ether ammonium sulfate, 20-25 parts of deionized water, 2.8-4.1 parts of initiator, 48-60 parts of aqueous solution, and 65-85 parts of oil-based solution.

[0015] The beneficial effects of this invention are: The invention is characterized in that, in step one, a nucleophilic substitution reaction is carried out by adding phenylphosphonic dichloro, m-phenylenediamine, and triethylamine to obtain an aminoated flame retardant. Then, the aminoated flame retardant and vanillin are mixed to undergo a Schiff base reaction to obtain a hydroxylated flame retardant. Furthermore, under a nitrogen atmosphere, the hydroxylated flame retardant, the hydroxyl-containing antioxidant 2,6-di-tert-butyl-4-hydroxymethylphenol, isophorone diisocyanate, and dibutyltin dilaurate are mixed to undergo an addition reaction between isocyanate and hydroxyl groups. After a period of reaction, hydroxylated carbon nanotubes and isocyanate groups are further added for further reaction to obtain modified carbon nanotubes.

[0016] This step secures the phenolic antioxidant 2,6-di-tert-butyl-4-hydroxymethylphenol and the hydroxylated flame retardant to the carbon nanotube surface via strong carbamate bonds. When the material is heated or exposed to light and generates free radicals, the phenolic hydroxyl groups in the antioxidant actively capture and neutralize these free radicals, converting them into stable products, thereby breaking the free radical chain reaction that leads to material aging. When the material burns, the Schiff base structure formed by m-phenylenediamine and vanillin decomposes, releasing nitrogen-containing non-flammable gases, diluting the concentration of combustible gases, isolating oxygen, and exerting a flame-retardant effect in the gas phase. In summary, the flame retardant, antioxidant, and carbon nanotubes are bonded together by strong covalent bonds to form a stable three-in-one functional unit, effectively avoiding the aggregation, migration, and failure problems of functional additives in traditional blending methods, and ensuring that each component continues to function efficiently throughout the entire material lifecycle.

[0017] The present invention is characterized by the following steps: A ring-opening reaction is initiated by adding glycidyl methacrylate and 2,2,4-trimethyl-1,2-dihydroquinoline to obtain an propylene-based antioxidant. Acrylamide, N,N-methylenebisacrylamide, and deionized water are then mixed to obtain an aqueous solution; butyl acrylate, methyl methacrylate, the propylene-based antioxidant, and acrylic acid are mixed to obtain an oily solution. An emulsifier, deionized water, an initiator, the aqueous solution, and the oily solution are then mixed and reacted at elevated temperatures to obtain an acrylic binder. On one hand, this step, through a chemical reaction, permanently anchors the high-performance antioxidant to the polymer network backbone of the binder via strong covalent bonds during polymerization, thus constructing an intrinsically anti-aging system. On the other hand, under the action of the initiator, the above monomers and propylene antioxidants undergo emulsion copolymerization, thereby forming a three-dimensional cross-linked network inside and between the latex particles. This cross-linked network not only improves the cohesive strength, heat resistance and solvent resistance of the binder, but also makes the polymer skeleton itself more robust, making it difficult for degradation reactions such as main chain breakage under the action of heat, oxygen and light to occur, which lead to aging.

[0018] The present invention is characterized by mixing polyvinylpyrrolidone, acrylic binder, modified carbon nanotubes, aromatic microencapsulation agent, and N-methylpyrrolidone to obtain a mixture; then mixing graphene and N-methylpyrrolidone, ultrasonically dispersing them evenly, and adding them to the mixture to obtain a graphene dispersion. The graphene dispersion is then uniformly coated onto the surface of a base fabric to obtain a graphene heating base fabric.

[0019] Graphene, as the main material for electron transport and heat generation in the system, allows electrons to move through the splines of graphene after an electric current is applied. 2 High-speed motion within a hybrid carbon atom network efficiently converts electrical energy into heat through the Joule effect. Furthermore, carbon nanotubes, with their excellent electrical and thermal conductivity, act like wires, connecting dispersed graphene sheets and filling the contact gaps between them. This significantly reduces interfacial contact resistance, forming a more interconnected and stable three-dimensional conductive network. Therefore, at the same voltage, the overall resistance of the base fabric is lower, allowing for a larger current flow, resulting in a significant improvement in the energy conversion efficiency to heat, manifested as faster heating, higher final temperature, and better heating effect. Simultaneously, an acrylic binder with good flame retardancy and anti-aging properties forms a strong and flexible adhesive layer between the graphene / carbon nanotubes and between them and the base fabric, ensuring the mechanical stability and durability of the conductive network. The anti-aging and flame retardant properties of the acrylic binder also ensure the performance stability of the entire heating layer under long-term thermal cycling. Additionally, aromatic microcapsules encapsulate fragrance; when the base fabric heats up, the generated heat slowly stimulates the microcapsules to release the fragrance, combining thermotherapy and aromatherapy for enhanced comfort. Detailed Implementation

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Raw material source: Hydroxylated carbon nanotubes, provided by Xi'an Qiyue Biotechnology Co., Ltd., with a particle size of 25 nm; aromatic microencapsulation agent, specifically eucalyptus fragrance microcapsule finishing agent, provided by Jining Fangyu Chemical Co., Ltd., model number TZSZ38; polyvinylpyrrolidone, model number Sokalan K30 P; graphene, specifically reduced graphene oxide, provided by Dongguan Qiaoke Chemical Co., Ltd., model number R487602; base fabric, specifically leather base fabric, made of polyester, with a density of 60×40 g / m³. 2 One part by mass is 1g.

[0022] Example 1: Step S1: Anhydrous acetonitrile and phenylphosphonic dichloride were mixed evenly to obtain a reaction solution; under a nitrogen atmosphere, anhydrous acetonitrile and m-phenylenediamine were mixed, then triethylamine was added and the temperature was lowered to 2°C, and the reaction solution was added dropwise. After the dropwise addition was completed, the reaction was continued for 3.0 h, and then the temperature was raised to 25°C and the reaction was continued for 15 h. After the reaction was completed, the mixture was filtered, rotary evaporated, precipitated, washed, and dried to obtain an amino-modified flame retardant; the molar ratio of phenylphosphonic dichloride to m-phenylenediamine was 1:2.15. Step S2: Mix vanillin and anhydrous ethanol to obtain a vanillin solution; under a nitrogen atmosphere, mix the aminated flame retardant and anhydrous ethanol, then add the vanillin solution dropwise. After the addition is complete, heat to 55℃ and react for 6.0 h. After the reaction is complete, rotary evaporate to obtain the hydroxylated flame retardant; the molar ratio of the aminated flame retardant to vanillin is 1:2.15. Step S3: Under a nitrogen atmosphere, isophorone diisocyanate, dibutyltin dilaurate, and N,N-dimethylformamide were mixed, and flame retardant reaction solution and antioxidant reaction solution were added dropwise at 30°C. After the addition was completed, the reaction was continued for 9 hours. Then, hydroxylated carbon nanotube dispersion was added, and the temperature was raised to 75°C and the reaction was continued for 10 hours. After the reaction was completed, the mixture was centrifuged, washed, and dried to obtain modified carbon nanotubes. 2,6-di-tert-butyl-4-hydroxymethylphenol and N,N-dimethylformamide were mixed to obtain an antioxidant reaction solution. Hydroxylated flame retardant and N,N-dimethylformamide were mixed to obtain a flame retardant reaction solution. Hydroxylated carbon nanotubes and N,N-dimethylformamide were mixed and ultrasonically dispersed to obtain a hydroxylated carbon nanotube dispersion. The mass ratio of isophorone diisocyanate, 2,6-di-tert-butyl-4-hydroxymethylphenol, hydroxylated flame retardant, and hydroxylated carbon nanotubes was 6:1:4.5:0.9. Step S4: Glycidyl methacrylate, 2,2,4-trimethyl-1,2-dihydroquinoline, and toluene solvent were mixed and reacted at 100°C for 6 hours. During the reaction, the polymerization inhibitor 4-methoxyphenol was added intermittently. After the reaction was completed, the mixture was rotary evaporated, washed, and dried to obtain the propylene antioxidant. The molar ratio of glycidyl methacrylate to 2,2,4-trimethyl-1,2-dihydroquinoline was 1.07:1. Step S5: Mix 20g acrylamide, 3g N,N-methylenebisacrylamide, and 25g deionized water to obtain an aqueous solution; mix 40g butyl acrylate, 15g methyl methacrylate, 8g propylene antioxidant, and 2g acrylic acid to obtain an oily solution; mix 0.5g ammonium persulfate, 0.3g sodium bicarbonate, and 2g deionized water to obtain an initiator; mix 2g alkylphenol polyoxyethylene ether emulsifier, 2g allyloxynonylphenol polyoxyethylene ether ammonium sulfate emulsifier, and 20g deionized water, stir evenly at 90℃, add 0.8g initiator, then add the aqueous solution, oily solution, and 1.7g initiator dropwise. After the dropwise addition is complete, keep warm for 35min, then cool to 30℃ and adjust the pH of the solution to neutral to obtain an acrylic adhesive; Step S6: Mix 2g of polyvinylpyrrolidone, 7g of acrylic binder, 4g of modified carbon nanotubes, 0.9g of aromatic microcapsule agent, and 45g of N-methylpyrrolidone, and disperse them evenly to obtain a mixed solution; mix 10g of graphene and 30g of N-methylpyrrolidone, disperse them evenly by ultrasonication, and add them to the mixed solution to obtain a graphene dispersion; coat the graphene dispersion evenly onto the surface of the base fabric to obtain a graphene heating base fabric.

[0023] Example 2: Step S1: Anhydrous acetonitrile and phenylphosphonic dichloride were mixed evenly to obtain a reaction solution; under a nitrogen atmosphere, anhydrous acetonitrile and m-phenylenediamine were mixed, then triethylamine was added and the temperature was lowered to 1°C, and the reaction solution was added dropwise. After the dropwise addition was completed, the reaction was continued for 2.7 h, and then the temperature was raised to 23°C and the reaction was continued for 12 h. After the reaction was completed, the mixture was filtered, rotary evaporated, precipitated, washed, and dried to obtain an amino-modified flame retardant; the molar ratio of phenylphosphonic dichloride to m-phenylenediamine was 1:2.15. Step S2: Mix vanillin and anhydrous ethanol to obtain a vanillin solution; under a nitrogen atmosphere, mix the aminated flame retardant and anhydrous ethanol, then add the vanillin solution dropwise. After the addition is complete, heat to 52℃ and react for 5.7 h. After the reaction is complete, rotary evaporate to obtain the hydroxylated flame retardant; the molar ratio of the aminated flame retardant to vanillin is 1:2.15. Step S3: Under a nitrogen atmosphere, isophorone diisocyanate, dibutyltin dilaurate, and N,N-dimethylformamide were mixed, and flame retardant reaction solution and antioxidant reaction solution were added dropwise at 29°C. After the addition was completed, the reaction was continued for 8 hours. Then, hydroxylated carbon nanotube dispersion was added, and the temperature was raised to 72°C and the reaction was continued for 9 hours. After the reaction was completed, the mixture was centrifuged, washed, and dried to obtain modified carbon nanotubes. 2,6-di-tert-butyl-4-hydroxymethylphenol and N,N-dimethylformamide were mixed to obtain antioxidant reaction solution. Hydroxylated flame retardant and N,N-dimethylformamide were mixed to obtain flame retardant reaction solution. Hydroxylated carbon nanotubes and N,N-dimethylformamide were mixed and ultrasonically dispersed to obtain hydroxylated carbon nanotube dispersion. The mass ratio of isophorone diisocyanate, 2,6-di-tert-butyl-4-hydroxymethylphenol, hydroxylated flame retardant, and hydroxylated carbon nanotubes was 6:1:4.5:0.9. Step S4: Glycidyl methacrylate, 2,2,4-trimethyl-1,2-dihydroquinoline, and toluene solvent were mixed and reacted at 95°C for 5.5 h. During the reaction, the polymerization inhibitor 4-methoxyphenol was added intermittently. After the reaction was completed, the mixture was rotary evaporated, washed, and dried to obtain the propylene antioxidant. The molar ratio of glycidyl methacrylate to 2,2,4-trimethyl-1,2-dihydroquinoline was 1.07:1. Step S5: Mix 20g acrylamide, 3g N,N-methylenebisacrylamide, and 25g deionized water to obtain an aqueous solution; mix 40g butyl acrylate, 15g methyl methacrylate, 8g propylene antioxidant, and 2g acrylic acid to obtain an oily solution; mix 0.5g ammonium persulfate, 0.3g sodium bicarbonate, and 2g deionized water to obtain an initiator; mix 2g alkylphenol polyoxyethylene ether emulsifier, 2g allyloxynonylphenol polyoxyethylene ether ammonium sulfate emulsifier, and 20g deionized water, stir evenly at 87℃, add 0.8g initiator, then add the aqueous solution, oily solution, and 1.7g initiator dropwise. After the dropwise addition is complete, keep warm for 30min, then cool to 27℃ and adjust the pH of the solution to neutral to obtain an acrylic adhesive; Step S6: Mix 2g of polyvinylpyrrolidone, 7g of acrylic binder, 4g of modified carbon nanotubes, 0.9g of aromatic microcapsule agent, and 45g of N-methylpyrrolidone, and disperse them evenly to obtain a mixed solution; mix 10g of graphene and 30g of N-methylpyrrolidone, disperse them evenly by ultrasonication, and add them to the mixed solution to obtain a graphene dispersion; coat the graphene dispersion evenly onto the surface of the base fabric to obtain a graphene heating base fabric.

[0024] Example 3: Step S1: Anhydrous acetonitrile and phenylphosphonic dichloride were mixed evenly to obtain a reaction solution; under a nitrogen atmosphere, anhydrous acetonitrile and m-phenylenediamine were mixed, then triethylamine was added and the temperature was lowered to 0°C, and the reaction solution was added dropwise. After the dropwise addition was completed, the reaction was continued for 2.5 hours, and then the temperature was raised to 20°C and the reaction was continued for 10 hours. After the reaction was completed, the mixture was filtered, rotary evaporated, precipitated, washed, and dried to obtain an amino-modified flame retardant; the molar ratio of phenylphosphonic dichloride to m-phenylenediamine was 1:2.15. Step S2: Mix vanillin and anhydrous ethanol to obtain a vanillin solution; under a nitrogen atmosphere, mix the aminated flame retardant and anhydrous ethanol, then add the vanillin solution dropwise. After the addition is complete, heat to 50℃ and react for 5.5 h. After the reaction is complete, rotary evaporate to obtain the hydroxylated flame retardant; the molar ratio of the aminated flame retardant to vanillin is 1:2.15. Step S3: Under a nitrogen atmosphere, isophorone diisocyanate, dibutyltin dilaurate, and N,N-dimethylformamide were mixed, and flame retardant reaction solution and antioxidant reaction solution were added dropwise at 27°C. After the addition was completed, the reaction was continued for 7 hours. Then, hydroxylated carbon nanotube dispersion was added, and the temperature was raised to 70°C and the reaction was continued for 8 hours. After the reaction was completed, the mixture was centrifuged, washed, and dried to obtain modified carbon nanotubes. 2,6-di-tert-butyl-4-hydroxymethylphenol and N,N-dimethylformamide were mixed to obtain an antioxidant reaction solution. Hydroxylated flame retardant and N,N-dimethylformamide were mixed to obtain a flame retardant reaction solution. Hydroxylated carbon nanotubes and N,N-dimethylformamide were mixed and ultrasonically dispersed to obtain a hydroxylated carbon nanotube dispersion. The mass ratio of isophorone diisocyanate, 2,6-di-tert-butyl-4-hydroxymethylphenol, hydroxylated flame retardant, and hydroxylated carbon nanotubes was 6:1:4.5:0.9. Step S4: Glycidyl methacrylate, 2,2,4-trimethyl-1,2-dihydroquinoline, and toluene solvent are mixed and reacted at 90°C for 5 hours. During the reaction, the polymerization inhibitor 4-methoxyphenol is added intermittently. After the reaction is completed, the mixture is rotary evaporated, washed, and dried to obtain the propylene antioxidant. The molar ratio of glycidyl methacrylate to 2,2,4-trimethyl-1,2-dihydroquinoline is 1.07:1. Step S5: Mix 20g acrylamide, 3g N,N-methylenebisacrylamide, and 25g deionized water to obtain an aqueous solution; mix 40g butyl acrylate, 15g methyl methacrylate, 8g propylene antioxidant, and 2g acrylic acid to obtain an oily solution; mix 0.5g ammonium persulfate, 0.3g sodium bicarbonate, and 2g deionized water to obtain an initiator; mix 2g alkylphenol polyoxyethylene ether emulsifier, 2g allyloxynonylphenol polyoxyethylene ether ammonium sulfate emulsifier, and 20g deionized water, stir evenly at 85℃, add 0.8g initiator, then add the aqueous solution, oily solution, and 1.7g initiator dropwise. After the dropwise addition is complete, keep warm for 25min, then cool to 25℃ and adjust the pH of the solution to neutral to obtain an acrylic adhesive; Step S6: Mix 2g of polyvinylpyrrolidone, 7g of acrylic binder, 4g of modified carbon nanotubes, 0.9g of aromatic microcapsule agent, and 45g of N-methylpyrrolidone, and disperse them evenly to obtain a mixed solution; mix 10g of graphene and 30g of N-methylpyrrolidone, disperse them evenly by ultrasonication, and add them to the mixed solution to obtain a graphene dispersion; coat the graphene dispersion evenly onto the surface of the base fabric to obtain a graphene heating base fabric.

[0025] Comparative Example 1: The propylene antioxidant was removed, and the rest was the same as in Example 1. The specific steps are as follows: Step S1: Anhydrous acetonitrile and phenylphosphonic dichloride were mixed evenly to obtain a reaction solution; under a nitrogen atmosphere, anhydrous acetonitrile and m-phenylenediamine were mixed, then triethylamine was added and the temperature was lowered to 2°C, and then the reaction solution was added dropwise. After the dropwise addition was completed, the reaction was continued for 3.0 h, and then the temperature was raised to 25°C and the reaction was continued for 15 h. After the reaction was completed, the mixture was filtered, rotary evaporated, precipitated, washed, and dried to obtain an amino-based flame retardant; the molar ratio of phenylphosphonic dichloride to m-phenylenediamine was 1:2.15. Step S2: Mix vanillin and anhydrous ethanol to obtain a vanillin solution; under a nitrogen atmosphere, mix the aminated flame retardant and anhydrous ethanol, then add the vanillin solution dropwise. After the addition is complete, heat to 55℃ and react for 6.0 h. After the reaction is complete, rotary evaporate to obtain the hydroxylated flame retardant; the molar ratio of the aminated flame retardant to vanillin is 1:2.15. Step S3: Under a nitrogen atmosphere, isophorone diisocyanate, dibutyltin dilaurate, and N,N-dimethylformamide were mixed, and flame retardant reaction solution and antioxidant reaction solution were added dropwise at 30°C. After the addition was completed, the reaction was continued for 9 hours. Then, hydroxylated carbon nanotube dispersion was added, and the temperature was raised to 75°C and the reaction was continued for 10 hours. After the reaction was completed, the mixture was centrifuged, washed, and dried to obtain modified carbon nanotubes. 2,6-di-tert-butyl-4-hydroxymethylphenol and N,N-dimethylformamide were mixed to obtain an antioxidant reaction solution. Hydroxylated flame retardant and N,N-dimethylformamide were mixed to obtain a flame retardant reaction solution. Hydroxylated carbon nanotubes and N,N-dimethylformamide were mixed and ultrasonically dispersed to obtain a hydroxylated carbon nanotube dispersion. The mass ratio of isophorone diisocyanate, 2,6-di-tert-butyl-4-hydroxymethylphenol, hydroxylated flame retardant, and hydroxylated carbon nanotubes was 6:1:4.5:0.9. Step S4: Mix 20g acrylamide, 3g N,N-methylenebisacrylamide, and 25g deionized water to obtain an aqueous solution; mix 40g butyl acrylate, 15g methyl methacrylate, and 2g acrylic acid to obtain an oily solution; mix 0.5g ammonium persulfate, 0.3g sodium bicarbonate, and 2g deionized water to obtain an initiator; mix 2g alkylphenol polyoxyethylene ether emulsifier, 2g allyloxynonylphenol polyoxyethylene ether ammonium sulfate emulsifier, and 20g deionized water, stir evenly at 90℃, add 0.8g initiator, then dropwise add the aqueous solution, oily solution, and 1.7g initiator. After the dropwise addition is complete, keep warm for 35min, then cool to 30℃ and adjust the pH of the solution to neutral to obtain an acrylic adhesive; Step S5: Mix 2g of polyvinylpyrrolidone, 7g of acrylic binder, 4g of modified carbon nanotubes, 0.9g of aromatic microcapsule agent, and 45g of N-methylpyrrolidone, and disperse them evenly to obtain a mixed solution; mix 10g of graphene and 30g of N-methylpyrrolidone, disperse them evenly by ultrasonication, and add them to the mixed solution to obtain a graphene dispersion; coat the graphene dispersion evenly onto the surface of the base fabric to obtain a graphene heating base fabric.

[0026] Comparative Example 2: The modified carbon nanotubes were removed, and the rest was the same as in Example 1. The specific steps are as follows: Step S1: Glycidyl methacrylate, 2,2,4-trimethyl-1,2-dihydroquinoline, and toluene solvent were mixed and reacted at 100°C for 6 hours. During the reaction, the polymerization inhibitor 4-methoxyphenol was added intermittently. After the reaction was completed, the product was rotary evaporated, washed, and dried to obtain the propylene antioxidant. The molar ratio of glycidyl methacrylate to 2,2,4-trimethyl-1,2-dihydroquinoline was 1.07:1. Step S2: Mix 20g acrylamide, 3g N,N-methylenebisacrylamide, and 25g deionized water to obtain an aqueous solution; mix 40g butyl acrylate, 15g methyl methacrylate, 8g propylene antioxidant, and 2g acrylic acid to obtain an oily solution; mix 0.5g ammonium persulfate, 0.3g sodium bicarbonate, and 2g deionized water to obtain an initiator; mix 2g alkylphenol polyoxyethylene ether emulsifier, 2g allyloxynonylphenol polyoxyethylene ether ammonium sulfate emulsifier, and 20g deionized water, stir evenly at 90℃, add 0.8g initiator, then dropwise add the aqueous solution, oily solution, and 1.7g initiator. After the dropwise addition is complete, keep warm for 35min, then cool to 30℃ and adjust the pH of the solution to neutral to obtain an acrylic adhesive; Step S3: Mix 2g of polyvinylpyrrolidone, 7g of acrylic binder, 0.9g of aromatic microcapsule agent, and 45g of N-methylpyrrolidone, and disperse them evenly to obtain a mixed solution; mix 10g of graphene and 30g of N-methylpyrrolidone, disperse them evenly by ultrasonication, and add them to the mixed solution to obtain a graphene dispersion; coat the graphene dispersion evenly onto the surface of the base fabric to obtain a graphene heating base fabric.

[0027] Testing and experimentation: Flame retardant performance test: The graphene dispersion prepared in this invention was coated onto the surface of a glass plate and cured at 60℃ for 4 hours to form a film, thus obtaining a sample. The oxygen index value of the sample was tested according to GB / T 2406.1-2008 "Determination of Combustion Behavior of Plastics by Oxygen Index Method Part 1: Guidelines".

[0028] Anti-aging performance test: The graphene dispersion prepared in this invention was coated onto the surface of a glass plate and cured at 50-60℃ for 4-5 hours to form a film with a thickness of 50 μm. The sample prepared in this invention was placed in an aging test chamber with the temperature set at 70℃ and the humidity set at 80%. After aging for 100 hours, the thermal properties of the sample were tested.

[0029] Thermal performance testing: The graphene dispersion prepared in this invention was coated onto the surface of a glass plate and cured at 50-60℃ for 4-5 hours to form a film with a thickness of 50 μm. Under a working voltage of 5V, the sample converted electrical energy into heat energy, which was reflected in the temperature rise of the film. The temperature of the sample was measured at multiple points using a temperature recorder, and the average value was recorded. The thermal equilibrium temperature of the sample was also recorded. The results are shown in the table below: Conclusion: In Examples 1-3, the dosage remained unchanged, with only some reaction parameters modified. Experimental data showed no significant fluctuations in the performance of the samples.

[0030] Comparative Example 1: The propylene antioxidant was removed, and the rest was the same as in Example 1. Experimental data showed that, compared to Example 1, the thermal equilibrium temperature after aging decreased to 40.1℃. The reason for this is that the propylene antioxidant contains the antioxidant 2,2,4-trimethyl-1,2-dihydroquinoline. Through a chemical reaction, this high-performance antioxidant is covalently anchored in the polymer network backbone of the binder during polymerization, effectively improving the material's anti-aging properties. Therefore, removing it reduces the anti-aging performance, and the thermal properties of the aged sample decrease.

[0031] Comparative Example 2: The modified carbon nanotubes were removed, while the rest remained the same as in Example 1. Experimental data showed that, compared to Example 1, the oxygen index decreased to 25.1%, the pre-aging thermal equilibrium temperature decreased to 36.1℃, and the post-aging thermal equilibrium temperature decreased to 31.4℃. The reason for this is that the modified carbon nanotubes contain the phenolic antioxidant 2,6-di-tert-butyl-4-hydroxymethylphenol. The phenolic hydroxyl groups can actively capture and neutralize free radicals, thereby preventing the free radical chain reaction that leads to material aging. Therefore, removing it reduces the anti-aging performance and decreases the thermal properties of the aged sample. Furthermore, carbon nanotubes and hydroxylated flame retardants can synergistically retard flames, improving the flame retardant performance of the material; therefore, removing them also reduces the oxygen index.

[0032] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process method article or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process method article or apparatus.

[0033] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A preparation process for a graphene heating substrate, characterized in that: Includes the following steps: A dispersant, acrylic binder, modified carbon nanotubes, aromatic microencapsulation agent, and solvent are mixed and dispersed evenly to obtain a mixture. Graphene and solvent are mixed, ultrasonically dispersed evenly, and then added to the mixture to obtain a graphene dispersion. The graphene dispersion is evenly coated onto the surface of a base fabric to obtain a graphene heating base fabric. The modified carbon nanotubes are obtained by grafting isophorone diisocyanate with hydroxylated flame retardant and antioxidant 2,6-di-tert-butyl-4-hydroxymethylphenol, followed by further modification of the carbon nanotubes; the acrylic antioxidant is introduced into the acrylic monomer and polymerized under the action of an initiator to obtain the acrylic adhesive.

2. The preparation process of a graphene heating substrate according to claim 1, characterized in that: The solvent is N-methylpyrrolidone; the dispersant is polyvinylpyrrolidone; the content of each component in the graphene dispersion is as follows (by mass): 1.5-3.0 parts dispersant, 6-8 parts acrylic binder, 3-5 parts modified carbon nanotubes, 0.8-1.0 parts aromatic microencapsulation agent, 70-80 parts solvent, and 8-12 parts graphene.

3. The preparation process of a graphene heating substrate according to claim 2, characterized in that: The preparation process of modified carbon nanotubes is as follows: Step S1: Mix anhydrous acetonitrile and phenylphosphonic dichloro evenly to obtain a reaction solution; under a nitrogen atmosphere, mix anhydrous acetonitrile and m-phenylenediamine, then add triethylamine and cool to 0-2℃, then add the reaction solution dropwise. After the dropwise addition is complete, continue the reaction for 2.5-3.0h, then heat to 20-25℃ and continue the reaction for 10-15h. After the reaction is complete, filter, rotary evaporate, precipitate, wash and dry to obtain an aminoated flame retardant. Step S2: Mix vanillin and anhydrous ethanol to obtain a vanillin solution; under a nitrogen atmosphere, mix the aminated flame retardant and anhydrous ethanol, then add the vanillin solution dropwise. After the addition is complete, heat to 50-55℃ and react for 5.5-6.0 h. After the reaction is complete, rotary evaporate to obtain a hydroxylated flame retardant; mix the hydroxylated flame retardant and N,N-dimethylformamide to obtain a flame retardant reaction solution. Step S3: Mix 2,6-di-tert-butyl-4-hydroxymethylphenol and N,N-dimethylformamide to obtain an antioxidant reaction solution; mix hydroxylated carbon nanotubes and N,N-dimethylformamide and ultrasonically disperse to obtain a hydroxylated carbon nanotube dispersion; under a nitrogen atmosphere, mix isophorone diisocyanate, dibutyltin dilaurate, and N,N-dimethylformamide, and add the flame retardant reaction solution and antioxidant reaction solution dropwise at 27-30℃. After the addition is complete, continue the reaction for 7-9 hours, then add the hydroxylated carbon nanotube dispersion, raise the temperature to 70-75℃ and continue the reaction for 8-10 hours. After the reaction is complete, centrifuge, wash, and dry to obtain modified carbon nanotubes.

4. The preparation process of a graphene heating substrate according to claim 3, characterized in that: In step S1, the molar ratio of phenylphosphonic dichloride and m-phenylenediamine is 1:(2.1-2.2).

5. The preparation process of a graphene heating substrate according to claim 3, characterized in that: In step S2, the reaction molar ratio of the aminated flame retardant to vanillin is 1:(2.1-2.2).

6. The preparation process of a graphene heating substrate according to claim 3, characterized in that: In step S3, the reaction mass ratio of isophorone diisocyanate, 2,6-di-tert-butyl-4-hydroxymethylphenol, hydroxylated flame retardant, and hydroxylated carbon nanotubes is (5-7):1:(3.5-5.4):(0.8-1.0).

7. The preparation process of a graphene heating substrate according to claim 2, characterized in that: The preparation process of acrylic adhesive is as follows: Step 1: Glycidyl methacrylate, 2,2,4-trimethyl-1,2-dihydroquinoline, and toluene solvent are mixed and reacted at 90-100℃ for 5-6 hours. During the reaction, the polymerization inhibitor 4-methoxyphenol is added intermittently. After the reaction is completed, the mixture is rotary evaporated, washed, and dried to obtain the propylene antioxidant. Butyl acrylate, methyl methacrylate, the propylene antioxidant, and acrylic acid are mixed to obtain an oily solution. Step 2: Mix the emulsifier alkylphenol polyoxyethylene ether, the emulsifier allyloxynonylphenol polyoxyethylene ether ammonium sulfate, and deionized water. Stir evenly at 85-90℃, then add the initiator. Add the aqueous solution, oil solution, and initiator dropwise. After the dropwise addition is complete, keep warm for 25-35 minutes, then cool down to 25-30℃ and adjust the pH of the solution to neutral to obtain the acrylic adhesive.

8. The preparation process of a graphene heating substrate according to claim 7, characterized in that: In step 1, the molar ratio of glycidyl methacrylate to 2,2,4-trimethyl-1,2-dihydroquinoline is (1.05-1.10):

1.

9. The preparation process of a graphene heating substrate according to claim 7, characterized in that: In step 2, 20-25 parts of acrylamide, 3-5 parts of N,N-methylenebisacrylamide, and 25-30 parts of deionized water are mixed to obtain an aqueous solution; 40-50 parts of butyl acrylate, 15-20 parts of methyl methacrylate, 8-12 parts of propylene antioxidant, and 2-3 parts of acrylic acid are mixed to obtain an oil-based solution; 0.5-0.7 parts of ammonium persulfate, 0.3-0.4 parts of sodium bicarbonate, and 2-3 parts of deionized water are mixed to obtain an initiator; the content of each component of the acrylic adhesive is as follows (by mass): 2-3 parts of alkylphenol polyoxyethylene ether, 2-3 parts of allyloxynonylphenol polyoxyethylene ether ammonium sulfate, 20-25 parts of deionized water, 2.8-4.1 parts of initiator, 48-60 parts of aqueous solution, and 65-85 parts of oil-based solution.

10. A graphene-based heating fabric, characterized in that, Prepared according to any one of the preparation processes described in claims 1-9.

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