Fireproof and waterproof modified tunnel lighting wire and preparation method thereof

Abstract

The invention belongs to the technical field of wire materials, and provides a fireproof and waterproof modified tunnel lighting wire and a preparation method thereof. The preparation method comprises the following steps: mixing 4, 4 '-diaminodiphenyl ether with a small amount of octylamine to introduce a hydrophobic group on the structure of a diamine monomer so as to enhance the waterproof performance of a polymer, adding polymethyl methacrylate microspheres as a template material, uniformly dispersing the microspheres in a polyimide solution, and removing the microspheres after solvent treatment to form a micro-void structure, so as to obtain the polymer. The weight of the material is reduced, the heat dissipation effect is enhanced, meanwhile, the heat insulation performance is improved, the pterostilbene phosphate flame retardant and the modified flame retardant are added into the final composite material, and the flame retardants release phosphoric acid and inert gas during combustion to form a protection carbon layer for isolating a fire source and inhibit free radicals in the combustion process, so that the excellent flame retardant effect is achieved, and the service life of the composite material is prolonged. The low-smoke and non-toxic gas during combustion is ensured, and the low-smoke and halogen-free requirements are met.

Description

Technical Field

[0001] The invention belongs to the technical field of wire materials and relates to a fireproof and waterproof modified tunnel lighting wire and a preparation method thereof. Background Art

[0002] The tunnel environment places high demands on the flame retardancy, waterproofness and durability of lighting wires. However, traditional tunnel lighting wire materials have obvious deficiencies in flame retardancy and waterproofness. Traditional wire materials usually use halogen-containing polymers, such as polyvinyl chloride. These materials release a large amount of toxic and corrosive halogen gas when burned. In a highly closed environment such as a tunnel, this gas will accumulate rapidly, affecting evacuation and rescue, and posing a serious threat to personal safety and infrastructure. In addition, the flame retardancy of traditional materials is limited. When encountering high temperature or fire source, it is easy to burn and spread, and it is difficult to effectively suppress the fire. At the same time, the tunnel environment is humid. The insulation and physical properties of traditional wire materials will drop significantly in a long-term humid or water-immersed environment, which is easy to cause safety hazards such as leakage and short circuit. Therefore, in the application of tunnel lighting wires, a material with good flame retardant effect is needed, which is low in smoke, halogen-free and has good waterproof properties. Summary of the invention

[0003] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a fireproof and waterproof modified tunnel lighting wire and a preparation method thereof, by introducing a hydrophobic group on a diamine monomer to improve the hydrophobic property of the material, adopting a composite flame retardant system, introducing pterostilbene phosphate and a modified flame retardant. Pterostilbene phosphate decomposes phosphoric acid when heated to generate a protective carbonized layer, effectively isolating oxygen and heat sources, and nitrogen elements generate inert gas at high temperatures to improve the flame retardant effect, thereby meeting the needs of actual production.

[0004] To achieve this object, the present invention adopts the following technical solutions:

[0005] In a first aspect, the present invention provides a method for preparing a fireproof and waterproof modified tunnel lighting wire, the preparation method comprising:

[0006] Step S1, adding a diamine monomer and octylamine to a first portion of N-methylpyrrolidone, heating to a first temperature and continuously stirring at a first stirring speed to obtain a modified diamine solution, then adding a dianhydride monomer to a second portion of N-methylpyrrolidone, stirring evenly at a second stirring speed to obtain a dianhydride solution, adding the modified diamine solution to the dianhydride solution, heating to the first temperature under nitrogen protection to fully react, and obtaining a polyimide solution;

[0007] Step S2, adding a polymethyl methacrylate microsphere solution to a polyimide solution, uniformly dispersing by ultrasonication, standing at room temperature, and fully drying at a first temperature under a vacuum state, soaking the dried polyimide in a toluene solution to dissolve and remove the polymethyl methacrylate microspheres, washing, and drying under vacuum at a second temperature to obtain a modified polyimide;

[0008] Step S3, after the modified polyimide, low-density polyethylene and epoxy resin are mixed and melted at the third temperature, pterostilbene phosphate flame retardant, modified flame retardant, antioxidant, plasticizer, lubricant, inorganic filler and diphenylmethane tetracarboxylic anhydride are added in sequence and mixed evenly, and after extrusion, they are coated on the surface of the copper wire core to obtain a fireproof and waterproof modified tunnel lighting wire.

[0009] When a diamine monomer is reacted with a small amount of octylamine to form a modified diamine, it has many effects on the final material, as follows: (1) Enhanced hydrophobicity. Octylamine has a long alkyl chain and is a non-polar hydrophobic segment that can effectively repel water molecules. By introducing a small amount of octylamine on the basis of the diamine monomer, local hydrophobic segments appear on the polyimide molecular chain, thereby reducing the affinity of the material surface for water molecules, hindering the direct contact between water molecules and the material surface, and reducing the possibility of water molecules penetrating into the material. At the same time, van der Waals forces or hydrophobic effects will be generated between the hydrophobic segments of octylamine. This mutual attraction makes the molecular chains of the material more closely arranged, reducing the pore space inside the material for water molecules to enter. In addition, the long-chain alkyl structure in octylamine can reduce the surface free energy of the material due to its hydrophobic properties, making it difficult for water molecules to adhere to the surface of the material, thereby enhancing the waterproof performance; (2 ) The diamine monomer contains an aromatic ring structure. The aromatic ring structure gives the polyimide chain a high thermal stability through the conjugation effect and the strength of the carbon-carbon bond. The aromatic ring is difficult to break and can maintain structural integrity at high temperatures, preventing the polymer chain from decomposing prematurely. The introduction of a small amount of octylamine does not destroy the high thermal stability of the aromatic system. On the contrary, it will enhance the density and thermal decomposition temperature of the molecular chain through alternating hydrophobic chains and aromatic ring structures. At the same time, the alkyl chain of octylamine will first decompose during combustion, forming a carbonized layer and blocking the further entry of oxygen, thereby enhancing the flame retardancy of the material; (3) The aromatic ring structure of the diamine monomer usually generates less volatile substances during decomposition, and the amount of smoke generated is smaller than that of other polymer materials. During combustion, the alkyl chain preferentially forms a carbonized layer during thermal cracking to prevent further decomposition of the internal material. The carbonized layer formed by the chain structure of octylamine is relatively tight, which inhibits the escape of smoke particles.

[0010] By introducing polymethyl methacrylate microspheres into polyimide and subsequently dissolving and removing them to form a microporous structure, the microporous structure significantly reduces the overall density of polyimide, which helps to reduce the weight of tunnel lighting wires; the air or gas in the microscopic pores has a low thermal conductivity, which effectively prevents the conduction of heat inside the material, giving the material better thermal insulation properties; at the same time, the pore structure limits the flow of oxygen in the material, slowing down the spread of flames, and the air barrier in the pores reduces the contact of heat and oxygen with the polymer matrix during a fire, thereby improving the flame retardancy of the material.

[0011] Step A, adding pterostilbene and sodium carbonate to tetrahydrofuran in sequence, heating to a first temperature and continuously stirring at a first stirring speed to obtain a mixture, then adding triphenyl phosphate to the mixture and fully reacting, cooling to room temperature after the reaction, filtering and washing, and then vacuum drying at a fourth temperature to obtain a pterostilbene phosphate flame retardant.

[0012] Pterostilbene and sodium carbonate are mixed and heated in a tetrahydrofuran solution. Sodium carbonate provides an alkaline environment in the solution, which can convert the phenolic hydroxyl group of pterostilbene into phenolate by deprotonation. Phenolate is a relatively active nucleophilic reagent and is easier to undergo subsequent phosphating reaction. Triphenyl phosphate is added to the solution of pterostilbene phenolate. The phosphorus center of diphenyl chlorophosphate has a high electrophilicity and can undergo a nucleophilic substitution reaction with pterostilbene phenolate to generate phosphate. At high temperature, pterostilbene phosphate will first decompose to generate products such as phosphoric acid and pyrophosphate. Phosphoric acid has good dehydration ability and can react with functional groups such as hydroxyl and carboxyl in the substrate to promote carbonization reaction and form a carbonized layer on the surface of the material. The generated phosphoric acid and pyrophosphate can act as catalysts at high temperature to promote dehydration, cross-linking and other reactions of the polyimide substrate, accelerate the breakage of the carbon chain structure, and further form a stable carbon layer. This carbon layer has high thermal stability and physical strength, can block heat and oxygen, and thus effectively prevent the material from further decomposing.

[0013] The active groups such as phosphate and metaphosphate generated after the decomposition of pterostilbene phosphate can react with the free radicals generated by combustion to form stable compounds, such as water and small molecular phosphates, thereby interrupting the chain reaction process of combustion. The phenolic hydroxyl group and aromatic ring structure in the pterostilbene molecule have the function of capturing combustion free radicals. The benzene ring structure can absorb the energy of free radicals through π electron conjugation, converting the free radicals into more stable molecules. At the same time, the phenolic hydroxyl group can also react with oxygen free radicals to generate water molecules, which further reduces the activity of combustion. Pterostilbene phosphate contains phosphorus and aromatic structures. These two components cooperate with each other in the carbonization process to generate a thicker and denser carbon layer, which can insulate heat and oxygen, and can also provide mechanical protection at high temperatures, blocking oxygen from entering the surface of the substrate and preventing heat from being transferred to the lower layer. The decomposition products of phosphate can inhibit the formation of smoke, because these products can capture carbon free radicals during combustion, thereby reducing the generation of carbon soot particles, making the material have low smoke characteristics.

[0014] Step B, adding 2-amino-5-methyl-1,3,4-thiadiazole to anhydrous ethanol, heating to the fifth temperature and maintaining stirring at the first stirring speed, then adding p-hydroxybenzaldehyde, and adding 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide after continuous reaction, continuing the reaction, cooling to room temperature after the reaction is completed, filtering and washing, and then placing under vacuum drying at the fourth temperature to obtain a modified flame retardant.

[0015] First, the amino group in 2-amino-5-methyl-1,3,4-thiadiazole reacts with the aldehyde group of p-hydroxybenzaldehyde to form an imine structure (i.e., Schiff base). The Schiff base structure has a certain electronic stability and can maintain chemical stability at high temperatures. In this way, during the combustion of the material, the imine bond that is not easily decomposed can lay the foundation for the subsequent carbonization reaction. p-Hydroxybenzaldehyde provides benzene rings and hydroxyl groups, which help to increase the pyrolysis temperature of the material. Under the combustion environment, the benzene ring can absorb heat and delay decomposition, while promoting the formation of the carbonized layer, while the hydroxyl group can stabilize the carbonized layer through hydrogen bonds, which helps to improve the physical strength of the carbon layer. The carbonization process is one of the important mechanisms for the flame retardancy of the material. By introducing phosphorus- and nitrogen-containing structures, these structures can decompose thermally stable pyrophosphate and carbonized nitrogen substances at high temperatures during the combustion process, thereby forming a dense carbon layer. The carbon layer isolates oxygen from entering the combustion area, reduces further oxidation reactions, and slows down or even stops the combustion. 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) absorbs a large amount of heat when it decomposes, effectively reducing the surface temperature of the material and thus inhibiting combustion. The decomposition reaction of phosphorus-containing groups is an endothermic reaction. After absorbing the heat of combustion, the combustion temperature is reduced, thereby delaying the spread of the flame. During the combustion process, the phosphorus-containing free radicals generated by the decomposition of phosphorus oxides will combine with the active free radicals in the flame, thereby reducing the number of these free radicals. Flame combustion requires these free radicals to participate in chain reactions. Capturing free radicals can effectively inhibit chain reactions and reduce the propagation rate of flames. The hydroxyl groups of p-hydroxybenzaldehyde also form hydrogen bonds during the carbonization process. This hydrogen bond enhances the physical strength of the carbonized layer, helps to delay the decomposition of the carbon layer, and allows the carbon layer to continue to cover the surface of the material and isolate the flame and oxygen.

[0016] As a preferred technical solution of the present invention, in step S1, the amount of the diamine monomer is 20-30 mmol, for example, it can be 20 mmol, 21 mmol, 22 mmol, 23 mmol, 24 mmol, 25 mmol, 26 mmol, 27 mmol, 28 mmol, 29 mmol or 30 mmol, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0017] In some optional examples, the amount of octylamine is 10-20% of the amount of diamine monomer, for example, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19% or 20%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0018] In some optional examples, the volume of the first portion of N-methylpyrrolidone is 60-80 mL, for example, it can be 60 mL, 62 mL, 64 mL, 66 mL, 68 mL, 70 mL, 72 mL, 74 mL, 76 mL, 78 mL or 80 mL, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0019] In some optional instances, the first temperature is 80-90°C, for example, it can be 80°C, 81°C, 82°C, 83°C, 84°C, 85°C, 86°C, 87°C, 88°C, 89°C or 90°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0020] In some optional examples, the first stirring speed is 300-400rpm, for example, it can be 300rpm, 310rpm, 320rpm, 330rpm, 340rpm, 350rpm, 360rpm, 370rpm, 380rpm, 390rpm or 400rpm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0021] In some optional examples, the first stirring speed is continued for 60-80 min, for example, 60 min, 62 min, 64 min, 66 min, 68 min, 70 min, 72 min, 74 min, 76 min, 78 min or 80 min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0022] In some optional examples, the amount of the diamine monomer is 20-30 mmol, for example, 20 mmol, 21 mmol, 22 mmol, 23 mmol, 24 mmol, 25 mmol, 26 mmol, 27 mmol, 28 mmol, 29 mmol or 30 mmol, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0023] In some optional examples, the volume of the second portion of N-methylpyrrolidone is 100-120 mL, for example, it can be 100 mL, 102 mL, 104 mL, 106 mL, 108 mL, 110 mL, 112 mL, 114 mL, 116 mL, 118 mL or 120 mL, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0024] In some optional examples, the second stirring speed is 200-300 rpm, for example, it can be 200 rpm, 210 rpm, 220 rpm, 230 rpm, 240 rpm, 250 rpm, 260 rpm, 270 rpm, 280 rpm, 290 rpm or 300 rpm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0025] In some optional examples, the stirring time of the second stirring speed is 30-50 min, for example, it can be 30 min, 32 min, 34 min, 36 min, 38 min, 40 min, 42 min, 44 min, 46 min, 48 min or 50 min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0026] In some optional examples, the reaction time at the first temperature is 4-5h, for example, it can be 4.0h, 4.1h, 4.2h, 4.3h, 4.4h, 4.5h, 4.6h, 4.7h, 4.8h, 4.9h or 5.0h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0027] As a preferred technical solution of the present invention, in step S2, the volume of the polymethyl methacrylate microsphere solution is 20-30 mL, for example, it can be 20 mL, 21 mL, 22 mL, 23 mL, 24 mL, 25 mL, 26 mL, 27 mL, 28 mL, 29 mL or 30 mL, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0028] In some optional examples, the mass fraction of the polymethyl methacrylate microsphere solution is 2.5 wt.%.

[0029] In some optional examples, the particle size of the polymethyl methacrylate microspheres is 30 nm.

[0030] In some optional instances, the ultrasound time is 20-30 min, for example, it can be 20 min, 21 min, 22 min, 23 min, 24 min, 25 min, 26 min, 27 min, 28 min, 29 min or 30 min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0031] In some optional examples, the standing time at room temperature is 3-4h, for example, it can be 3.0h, 3.1h, 3.2h, 3.3h, 3.4h, 3.5h, 3.6h, 3.7h, 3.8h, 3.9h or 4.0h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0032] In some optional examples, the time for vacuum drying at the first temperature is 6-8h, for example, it can be 6.0h, 6.2h, 6.4h, 6.6h, 6.8h, 7.0h, 7.2h, 7.4h, 7.6h, 7.8h or 8.0h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0033] In some optional examples, the mass fraction of the toluene solution is 10-20wt.%, for example, it can be 10wt.%, 11wt.%, 12wt.%, 13wt.%, 14wt.%, 15wt.%, 16wt.%, 17wt.%, 18wt.%, 19wt.% or 20wt.%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0034] In some optional examples, the volume of the toluene solution is 200-300 mL, for example, it can be 200 mL, 210 mL, 220 mL, 230 mL, 240 mL, 250 mL, 260 mL, 270 mL, 280 mL, 290 mL or 300 mL, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0035] In some optional examples, the immersion time is 2-3h, for example, it can be 2.0mL, 2.1mL, 2.2mL, 2.3mL, 2.4mL, 2.5mL, 2.6mL, 2.7mL, 2.8mL, 2.9mL or 3.0mL, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0036] In some optional instances, the second temperature is 150-160°C, for example, it can be 150°C, 151°C, 152°C, 153°C, 154°C, 155°C, 156°C, 157°C, 158°C, 159°C or 160°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0037] In some optional examples, the second temperature vacuum drying time is 4-6h, for example, it can be 4.0h, 4.2h, 4.4h, 4.6h, 4.8h, 5.0h, 5.2h, 5.4h, 5.6h, 5.8h or 6.0h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0038] As a preferred technical solution of the present invention, in step S3, the mass of the modified polyimide is 80-100g, for example, it can be 80g, 82g, 84g, 86g, 88g, 90g, 92g, 94g, 96g, 98g or 100g, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0039] In some optional instances, the mass of the low-density polyethylene is 20-30g, for example, it can be 20g, 21g, 22g, 23g, 24g, 25g, 26g, 27g, 28g, 29g or 30g, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0040] In some optional examples, the mass of the epoxy resin is 20-30g, for example, it can be 20g, 21g, 22g, 23g, 24g, 25g, 26g, 27g, 28g, 29g or 30g, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0041] In some optional instances, the third temperature is 350-380°C, for example, it can be 350°C, 353°C, 356°C, 359°C, 362°C, 365°C, 368°C, 371°C, 374°C, 377°C or 380°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0042] In some optional examples, the mass of the pterostilbene phosphate flame retardant is 5-10g, for example, it can be 5.0g, 5.5g, 6.0g, 6.5g, 7.0g, 7.5g, 8.0g, 8.5g, 9.0g, 9.5g or 10.0g, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0043] In some optional examples, the mass of the modified flame retardant is 5-10g, for example, it can be 5.0g, 5.5g, 6.0g, 6.5g, 7.0g, 7.5g, 8.0g, 8.5g, 9.0g, 9.5g or 10.0g, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0044] In some optional examples, the mass of the antioxidant is 1-3g, for example, it can be 1.0g, 1.2g, 1.4g, 1.6g, 1.8g, 2.0g, 2.2g, 2.4g, 2.6g, 2.8g or 3.0g, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0045] In some optional examples, the mass of the plasticizer is 1-3g, for example, it can be 1.0g, 1.2g, 1.4g, 1.6g, 1.8g, 2.0g, 2.2g, 2.4g, 2.6g, 2.8g or 3.0g, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0046] In some optional examples, the mass of the inorganic filler is 1-3g, for example, it can be 1.0g, 1.2g, 1.4g, 1.6g, 1.8g, 2.0g, 2.2g, 2.4g, 2.6g, 2.8g or 3.0g, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0047] In some optional examples, the mass of the diphenylmethanetetracarboxylic anhydride is 30-50g, for example, it can be 30g, 32g, 34g, 36g, 38g, 40g, 42g, 44g, 46g, 48g or 50g, but it is not limited to the listed values, and other unlisted values ​​within the numerical range are equally applicable. As a preferred technical solution of the present invention, in step A, the amount of the substance of pterostilbene is 40-50mmol, for example, it can be 40mmol, 41mmol, 42mmol, 43mmol, 44mmol, 45mmol, 46mmol, 47mmol, 48mmol, 49mmol or 50mmol, but it is not limited to the listed values, and other unlisted values ​​within the numerical range are equally applicable.

[0048] In some optional examples, the amount of sodium carbonate is 140-160 mmol, for example, 140 mmol, 142 mmol, 144 mmol, 146 mmol, 148 mmol, 150 mmol, 152 mmol, 154 mmol, 156 mmol, 158 mmol or 160 mmol, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0049] In some optional examples, the volume of tetrahydrofuran is 400-500 mL, for example, 400 mL, 410 mL, 420 mL, 430 mL, 440 mL, 450 mL, 460 mL, 470 mL, 480 mL, 490 mL or 500 mL, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0050] In some optional examples, the stirring time of the first stirring speed is 20-30 min, for example, it can be 20 min, 21 min, 22 min, 23 min, 24 min, 25 min, 26 min, 27 min, 28 min, 29 min or 30 min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0051] In some optional examples, the amount of triphenyl phosphate is 100-120 mmol, for example, it can be 100 mmol, 102 mmol, 104 mmol, 106 mmol, 108 mmol, 110 mmol, 112 mmol, 114 mmol, 116 mmol, 118 mmol or 120 mmol, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0052] In some optional examples, the reaction time after adding triphenyl phosphate is 12-14h, for example, it can be 12.0h, 12.2h, 12.4h, 12.6h, 12.8h, 13.0h, 13.2h, 13.4h, 13.6h, 13.8h or 14.0h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0053] In some optional instances, the fourth temperature is 50-60°C, for example, it can be 50°C, 51°C, 52°C, 53°C, 54°C, 55°C, 56°C, 57°C, 58°C, 59°C or 60°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0054] In some optional examples, the vacuum drying time at the fourth temperature is 20-30h, for example, it can be 20h, 21h, 22h, 23h, 24h, 25h, 26h, 27h, 28h, 29h or 30h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0055] As a preferred technical solution of the present invention, in step B, the mass of the 2-amino-5-methyl-1,3,4-thiadiazole is 5-6 g, for example, it can be 5.0 g, 5.1 g, 5.2 g, 5.3 g, 5.4 g, 5.5.g, 5.6 g, 5.7 g, 5.8 g, 5.9 g or 6.0 g, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0056] In some optional examples, the volume of anhydrous ethanol is 150-170 mL, for example, it can be 150 mL, 152 mL, 154 mL, 156 mL, 158 mL, 160 mL, 162 mL, 164 mL, 166 mL, 168 mL or 170 mL, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0057] In some optional instances, the fifth temperature is 90-100°C, for example, it can be 90°C, 91°C, 92°C, 93°C, 94°C, 95°C, 96°C, 97°C, 98°C, 99°C or 100°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0058] In some optional examples, the stirring time of the first stirring speed is 2-3h, for example, it can be 2.0h, 2.1h, 2.2.h, 2.3h, 2.4h, 2.5h, 2.6h, 2.7h, 2.8h, 2.9h or 3.0h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0059] In some optional examples, the mass of the p-hydroxybenzaldehyde is 2-3 g, for example, it can be 2.0 g, 2.1 g, 2.2.g, 2.3 g, 2.4 g, 2.5 g, 2.6 g, 2.7 g, 2.8 g, 2.9 g or 3.0 g, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0060] In some optional examples, the reaction time after adding p-hydroxybenzaldehyde is 12-14h, for example, it can be 12.0h, 12.2h, 12.4h, 12.6h, 12.8h, 13.0h, 13.2h, 13.4h, 13.6h, 13.8h or 14.0h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0061] In some optional examples, the mass of the 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is 8-9 g, for example, 8.0 g, 8.1 g, 8.2 g, 8.3 g, 8.4 g, 8.5 g, 8.6 g, 8.7 g, 8.8 g, 8.9 g or 9.0 g, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0062] In some optional examples, the reaction time after adding 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is 16-18 h, for example, it can be 16.0 h, 16.2 h, 16.4 h, 16.6 h, 16.8 h, 17.0 h, 17.2 h, 17.4 h, 17.6 h, 17.8 h or 18.0 h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0063] In some optional examples, the vacuum drying time is 10-12 h, for example, it can be 10.0 h, 10.2 h, 10.4 h, 10.6 h, 10.8 h, 11.0 h, 11.2 h, 11.4 h, 11.6 h, 11.8 h or 12.0 h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0064] In a second aspect, the present invention provides a fireproof and waterproof modified tunnel lighting wire prepared using the preparation method described in the first aspect.

[0065] Compared with the prior art, the present invention has the following beneficial effects:

[0066] (1) The addition of pterostilbene phosphate significantly improves the flame retardancy of the material. Phosphate flame retardants decompose to form substances such as phosphoric acid and phosphates when burned. These products form a protective carbonized layer on the surface of the material to isolate oxygen and heat, significantly reducing the combustion rate and preventing further decomposition of the material. The polyphenolic hydroxyl groups and benzene rings in the molecular structure of pterostilbene help to generate stable carbon when heated, effectively improving the carbonization efficiency of the material.

[0067] (2) A small amount of octylamine groups are introduced into the 4,4'-diaminodiphenyl ether structure. The long-chain alkyl group in the octylamine structure has strong hydrophobicity and can be embedded in the polyimide molecular chain through chemical bonding, making the final material have excellent hydrophobicity. The hydrophobic group in the octylamine structure can effectively reduce the surface energy of the material and prevent water molecules from gathering and penetrating on the surface of the material;

[0068] (3) Introducing polymethyl methacrylate microspheres into the polymer matrix, a uniform microscopic pore structure is formed in polyimide through a template method. After the polymethyl methacrylate microspheres are dissolved, pores are left in the material, which not only reduces the weight of the material but also improves the thermal insulation performance, which has a good thermal stability gain for tunnel lighting wires;

[0069] (4) By using thiadiazole and phosphine oxide together, a phosphorus-nitrogen synergistic flame retardant mechanism is introduced. Thiadiazole, as a nitrogen source, can release inert gas nitrogen when heated. The active groups generated by the decomposition of phosphorus oxide inhibit the free radicals generated during the combustion process. This synergistic effect can greatly improve the flame retardant efficiency. The composite carbonized layer formed by phosphoric acid and nitrogen is more fire resistant than traditional flame retardants and significantly reduces the smoke generated during combustion. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] Figure 1 A flow chart of a method for preparing a fireproof and waterproof modified tunnel lighting wire provided in Examples 1-6 of the present invention;

[0071] Figure 2 This is the FT-IR spectrum of the modified flame retardant prepared in Example 1 of the present invention;

[0072] Figure 3 This is the SEM image of the modified polyimide prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0073] The technical solution of the present invention is described in detail below in conjunction with specific embodiments and their accompanying drawings. The embodiments recorded herein are specific embodiments of the present invention, which are used to illustrate the concept of the present invention; these descriptions are explanatory and exemplary and should not be construed as limitations on the embodiments of the present invention and the scope of protection of the present invention. In addition to the embodiments recorded herein, those skilled in the art can also adopt other obvious technical solutions based on the contents disclosed in the claims of this application and its specification, including technical solutions that adopt any obvious replacements and modifications to the embodiments recorded herein.

[0074] The chemical reagents used in the examples and comparative examples of the present invention are all commercially available products, and their brands, specifications and manufacturer information are as follows:

[0075] 4,4'-Diaminodiphenyl ether, purity ≥99%, Nantong Huishun Chemical Co., Ltd.;

[0076] Octylamine, purity ≥99%, Ningbo Sapphire Petrochemical Co., Ltd.;

[0077] N-methylpyrrolidone, purity ≥99%, Chongqing Zhongrun New Materials Co., Ltd.;

[0078] Pyromellitic anhydride, purity ≥99%, Shanghai Ketuo Chemical Technology Co., Ltd.;

[0079] Nitrogen, purity ≥99%, Nanjing Special Gas Factory Co., Ltd.;

[0080] Polymethyl methacrylate microsphere solution, solid content 2.5wt.%, Wuxi Ruige Biotechnology Co., Ltd.;

[0081] Toluene, purity ≥99%, Tianjin Fuyu Fine Chemical Co., Ltd.;

[0082] Low-density polyethylene, purity ≥99%, ExxonMobil Chemical Co.;

[0083] Epoxy resin, ICI viscosity 1.8~2.7, Huibo New Materials Technology (Shanghai) Co., Ltd.;

[0084] Antioxidant 168, purity ≥99%, Qingdao Xunneng Technology Co., Ltd.;

[0085] Antioxidant 1010, purity ≥99%, Qingdao Xunneng Technology Co., Ltd.;

[0086] Antioxidant 1076, purity ≥99%, Qingdao Xunneng Technology Co., Ltd.;

[0087] Glycerol, purity ≥95%, Nanjing Yongdu Chemical Co., Ltd.;

[0088] Epoxidized soybean oil, epoxy value ≥4.8, Dezhou Longda Oil Technology Co., Ltd.;

[0089] Stearic acid, acid value 205-211 mgKOH / g, Hangzhou Zanyu Oil Technology Co., Ltd.;

[0090] Zinc stearate, free acid ≤0.8%, Hangzhou Zanyu Oil Technology Co., Ltd.;

[0091] Calcium stearate, free acid ≤0.5%, Hangzhou Zanyu Oil Technology Co., Ltd.;

[0092] Talc powder, fineness 15 μm, Guilin Guiguang Talc Development Co., Ltd.;

[0093] Pterostilbene, purity ≥99%, Hangzhou Ruishu Biochemical Co., Ltd.;

[0094] Sodium carbonate, purity ≥99%, Jiangsu Huachang Chemical Co., Ltd.;

[0095] Tetrahydrofuran, purity ≥99%, Shandong Yangxin Longtai Chemical Co., Ltd.;

[0096] Triphenyl phosphate, purity ≥99%, Shanghai Yuanye Biotechnology Co., Ltd.;

[0097] 2-Amino-5-methyl-1,3,4-thiadiazole, purity ≥97%, Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0098] Anhydrous ethanol, purity ≥99%, Yonghua Chemical Co., Ltd.;

[0099] p-Hydroxybenzaldehyde, purity ≥99%, Shandong Jichuang Chemical Co., Ltd.;

[0100] 9,10-Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), purity ≥99%, Suzhou Hualun Chemical Co., Ltd.;

[0101] Other raw materials can be purchased from the market.

[0102] Example 1

[0103] This embodiment provides a method for preparing a fireproof and waterproof modified tunnel lighting wire, such as Figure 1 As shown, the preparation method specifically comprises the following steps:

[0104] Step A, 41 mmol of pterostilbene and 145 mmol of sodium carbonate are added to 410 mL of tetrahydrofuran in sequence, the mixture is heated to 82° C. and stirred at 320 rpm for 21 min to obtain a mixture, 106 mmol of triphenyl phosphate is added to the mixture and fully reacted for 12.3 h. After the reaction is completed, the mixture is cooled to room temperature, filtered and washed, and then vacuum dried at 53° C. for 22 h to obtain a pterostilbene phosphate flame retardant;

[0105] Step B, add 5.2g of 2-amino-5-methyl-1,3,4-thiadiazole to 154mL of anhydrous ethanol, raise the temperature to 93°C and keep stirring at 320rpm for 2.1h, then add 2.3g of p-hydroxybenzaldehyde, continue the reaction for 12.1h, then add 8.3g of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, continue the reaction for 16.4h, cool to room temperature after the reaction is completed, filter and wash, and then place under vacuum at 53°C for 10.6h to obtain a modified flame retardant;

[0106] Step S1, adding 22mmol 4,4'-diaminodiphenyl ether and 2.8mmol octylamine to 64mL N-methylpyrrolidone, heating to 83°C and stirring at 320rpm for 65min to obtain a modified diamine solution, then adding 23mmol pyromellitic anhydride to another 108mL N-methylpyrrolidone, stirring at 220rpm for 36min to obtain a dianhydride solution, adding the modified diamine solution to the dianhydride solution, heating to 85°C under nitrogen protection for sufficient reaction for 4.3h to obtain a polyimide solution;

[0107] Step S2, adding 21 mL of polymethyl methacrylate microsphere solution to the polyimide solution, ultrasonically dispersing for 24 minutes, standing at room temperature for 3.1 hours, and then fully drying at 84° C. for 6.3 hours under vacuum, and soaking the dried polyimide in a 12 wt.% toluene solution for 2.4 hours to dissolve and remove the polymethyl methacrylate microspheres, washing, and vacuum drying at 153° C. for 4.4 hours to obtain a modified polyimide;

[0108] Step S3, after 83g of modified polyimide, 26g of low-density polyethylene, and 22g of epoxy resin are mixed and melted at 356°C, 5.8g of pterostilbene phosphate flame retardant, 5.4g of modified flame retardant, 1.6g of antioxidant 168, 1.2g of glycerol, 1.7g of stearic acid, 2.1g of glass fiber, and 32g of diphenylmethanetetracarboxylic anhydride are added in sequence and mixed evenly, and then extruded and coated on the surface of the copper wire core to obtain a fireproof and waterproof modified tunnel lighting wire.

[0109] Figure 2 The FT-IR spectrum of the modified flame retardant prepared in this example is shown in Figure 2. From the spectrum of 2-amino-5-methyl-1,3,4-thiadiazole, it can be seen that the peak at 3200-3400 cm -1 The double peak in the range is -NH2 peak. In the modified flame retardant, it is replaced by imine peak, which proves that the amino group in 2-amino-5-methyl-1,3,4-thiadiazole reacts with the aldehyde group of p-hydroxybenzaldehyde to form a Schiff base reaction. -1 The pH absorption peak of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide disappeared at 1310 cm -1 The CN absorption peak appeared at , which proved that the Schiff base reaction occurred. Figure 3 This is a SEM picture of the modified polyimide in this example, and the porous structure of the modified polyimide can be clearly seen.

[0110] Example 2

[0111] This embodiment provides a method for preparing a fireproof and waterproof modified tunnel lighting wire, such as Figure 1 As shown, the preparation method specifically comprises the following steps:

[0112] Step A, 43 mmol of pterostilbene and 148 mmol of sodium carbonate are added to 450 mL of tetrahydrofuran in sequence, the mixture is heated to 85° C. and stirred at 340 rpm for 23 min to obtain a mixture, 109 mmol of triphenyl phosphate is added to the mixture and fully reacted for 12.7 h, after the reaction is completed, the mixture is cooled to room temperature, filtered and washed, and then vacuum dried at 51° C. for 21 h to obtain a pterostilbene phosphate flame retardant;

[0113] Step B, add 5.1g of 2-amino-5-methyl-1,3,4-thiadiazole to 158mL of anhydrous ethanol, raise the temperature to 95°C and keep stirring at 340rpm for 2.3h, then add 2.2g of p-hydroxybenzaldehyde, continue the reaction for 12.3h, then add 8.5g of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, continue the reaction for 16.7h, cool to room temperature after the reaction is completed, filter and wash, and then place under vacuum at 55°C for 10.8h to obtain a modified flame retardant;

[0114] Step S1, adding 24 mmol 4,4'-diaminodiphenyl ether and 3.8 mmol octylamine to 60 mL N-methylpyrrolidone, heating to 80°C and stirring at 340 rpm for 62 min to obtain a modified diamine solution, then adding 25 mmol pyromellitic anhydride to another 110 mL N-methylpyrrolidone, stirring at 240 rpm for 32 min to obtain a dianhydride solution, adding the modified diamine solution to the dianhydride solution, heating to 82°C under nitrogen protection for sufficient reaction for 4.1 h to obtain a polyimide solution;

[0115] Step S2, adding 23 mL of polymethyl methacrylate microsphere solution to the polyimide solution, ultrasonically dispersing for 20 minutes, standing at room temperature for 3.6 hours, and then fully drying at 87° C. for 6.8 hours under vacuum, and soaking the dried polyimide in 11 wt.% toluene solution for 2.6 hours to dissolve and remove the polymethyl methacrylate microspheres, washing, and vacuum drying at 154° C. for 4.7 hours to obtain a modified polyimide;

[0116] Step S3, after 88g of modified polyimide, 22g of low-density polyethylene, and 24g of epoxy resin are mixed and melted at 359°C, 6.3g of pterostilbene phosphate flame retardant, 5.3g of modified flame retardant, 1.2g of antioxidant 1010, 1.7g of epoxy soybean oil, 1.5g of zinc stearate, 2.4g of talc, and 36g of diphenylmethanetetracarboxylic anhydride are added in sequence and mixed evenly, and then extruded and coated on the surface of the copper wire core to obtain a fireproof and waterproof modified tunnel lighting wire.

[0117] Example 3

[0118] This embodiment provides a method for preparing a fireproof and waterproof modified tunnel lighting wire, such as Figure 1 As shown, the preparation method specifically comprises the following steps:

[0119] Step A, 40 mmol of pterostilbene and 143 mmol of sodium carbonate are added to 420 mL of tetrahydrofuran in sequence, the mixture is heated to 83° C. and stirred at 360 rpm for 25 min to obtain a mixture, 111 mmol of triphenyl phosphate is added to the mixture and fully reacted for 12.2 h, after the reaction is completed, the mixture is cooled to room temperature, filtered and washed, and then vacuum dried at 55° C. for 24 h to obtain a pterostilbene phosphate flame retardant;

[0120] Step B, add 5.7g of 2-amino-5-methyl-1,3,4-thiadiazole to 150mL of anhydrous ethanol, raise the temperature to 93°C and keep stirring at 310rpm for 2.6h, then add 2.7g of p-hydroxybenzaldehyde, continue the reaction for 12.8h, then add 8.2g of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, continue the reaction for 16.3h, cool to room temperature after the reaction is completed, filter and wash, and then place under vacuum at 58°C for 10.3h to obtain a modified flame retardant;

[0121] Step S1, adding 22 mmol 4,4'-diaminodiphenyl ether and 3.1 mmol octylamine to 68 mL N-methylpyrrolidone, heating to 85°C and stirring at 370 rpm for 69 min to obtain a modified diamine solution, then adding 27 mmol pyromellitic anhydride to another 113 mL N-methylpyrrolidone, stirring at 220 rpm for 38 min to obtain a dianhydride solution, adding the modified diamine solution to the dianhydride solution, heating to 86°C under nitrogen protection for sufficient reaction for 4.5 h to obtain a polyimide solution;

[0122] Step S2, adding 20 mL of polymethyl methacrylate microsphere solution to the polyimide solution, ultrasonically dispersing for 24 minutes, standing at room temperature for 3.1 hours, and then fully drying at 84° C. for 6.7 hours under vacuum, and soaking the dried polyimide in a 15 wt.% toluene solution for 2.9 hours to dissolve and remove the polymethyl methacrylate microspheres, washing, and vacuum drying at 158° C. for 4.3 hours to obtain a modified polyimide;

[0123] Step S3, after 82g of modified polyimide, 27g of low-density polyethylene, and 25g of epoxy resin are mixed and melted at 364°C, 6.6g of pterostilbene phosphate flame retardant, 6.1g of modified flame retardant, 2.3g of antioxidant 1076, 2.0g of glycerol, 1.7g of calcium stearate, 2.6g of glass fiber, and 43g of diphenylmethanetetracarboxylic anhydride are added in sequence and mixed evenly, and then extruded and coated on the surface of the copper wire core to obtain a fireproof and waterproof modified tunnel lighting wire.

[0124] Example 4

[0125] This embodiment provides a method for preparing a fireproof and waterproof modified tunnel lighting wire, such as Figure 1 As shown, the preparation method specifically comprises the following steps:

[0126] Step A, 46 mmol of pterostilbene and 151 mmol of sodium carbonate are added to 450 mL of tetrahydrofuran in sequence, the temperature is raised to 87° C. and stirred at 380 rpm for 27 min to obtain a mixture, 113 mmol of triphenyl phosphate is added to the mixture and fully reacted for 13.1 h, after the reaction is completed, the mixture is cooled to room temperature, filtered and washed, and then placed at 56° C. for vacuum drying for 26 h to obtain a pterostilbene phosphate flame retardant;

[0127] Step B, add 5.2g of 2-amino-5-methyl-1,3,4-thiadiazole to 162mL of anhydrous ethanol, raise the temperature to 97°C and keep stirring at 360rpm for 2.7h, then add 2.3g of p-hydroxybenzaldehyde, continue the reaction for 13.2h, then add 8.6g of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, continue the reaction for 17.1h, cool to room temperature after the reaction is completed, filter and wash, and then place under vacuum at 59°C for 10.9h to obtain a modified flame retardant;

[0128] Step S1, adding 28 mmol 4,4'-diaminodiphenyl ether and 4.3 mmol octylamine to 75 mL N-methylpyrrolidone, heating to 87°C and stirring at 330 rpm for 74 min to obtain a modified diamine solution, then adding 26 mmol pyromellitic anhydride to another 115 mL N-methylpyrrolidone, stirring at 270 rpm for 42 min to obtain a dianhydride solution, adding the modified diamine solution to the dianhydride solution, heating to 84°C under nitrogen protection for sufficient reaction for 4.8 h to obtain a polyimide solution;

[0129] Step S2, adding 27 mL of polymethyl methacrylate microsphere solution to the polyimide solution, ultrasonically dispersing for 28 min, standing at room temperature for 3.6 h, and then fully drying at 82° C. for 7.6 h under vacuum, and soaking the dried polyimide in a 16 wt.% toluene solution for 2.6 h to dissolve and remove the polymethyl methacrylate microspheres, washing, and vacuum drying at 153° C. for 5.2 h to obtain a modified polyimide;

[0130] Step S3, after 93g of modified polyimide, 23g of low-density polyethylene, and 28g of epoxy resin are mixed and melted at 370°C, 7.3g of pterostilbene phosphate flame retardant, 6.7g of modified flame retardant, 2.6g of antioxidant 168, 2.4g of epoxy soybean oil, 2.1g of zinc stearate, 2.8g of talc, and 47g of diphenylmethanetetracarboxylic anhydride are added in sequence and mixed evenly, and then extruded and coated on the surface of the copper wire core to obtain a fireproof and waterproof modified tunnel lighting wire.

[0131] Example 5

[0132] This embodiment provides a method for preparing a fireproof and waterproof modified tunnel lighting wire, such as Figure 1 As shown, the preparation method specifically comprises the following steps:

[0133] Step A, 44 mmol of pterostilbene and 146 mmol of sodium carbonate are added to 480 mL of tetrahydrofuran in sequence, the mixture is heated to 88° C. and stirred at 340 rpm for 22 min to obtain a mixture, 115 mmol of triphenyl phosphate is added to the mixture and fully reacted for 13.4 h. After the reaction is completed, the mixture is cooled to room temperature, filtered and washed, and then vacuum dried at 53° C. for 22 h to obtain a pterostilbene phosphate flame retardant;

[0134] Step B, add 5.8g of 2-amino-5-methyl-1,3,4-thiadiazole to 168mL of anhydrous ethanol, raise the temperature to 94°C and keep stirring at 350rpm for 2.3h, then add 2.6g of p-hydroxybenzaldehyde, continue the reaction for 13.7h, then add 8.7g of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, continue the reaction for 17.4h, cool to room temperature after the reaction is completed, filter and wash, and then place under vacuum at 54°C for 11.3h to obtain a modified flame retardant;

[0135] Step S1, adding 25mmol 4,4'-diaminodiphenyl ether and 3.6mmol octylamine to 78mL N-methylpyrrolidone, heating to 84°C and stirring at 350rpm for 71min to obtain a modified diamine solution, then adding 27mmol pyromellitic anhydride to another 120mL N-methylpyrrolidone, stirring at 230rpm for 45min to obtain a dianhydride solution, adding the modified diamine solution to the dianhydride solution, heating to 86°C under nitrogen protection for sufficient reaction for 4.4h to obtain a polyimide solution;

[0136] Step S2, adding 25 mL of polymethyl methacrylate microsphere solution to the polyimide solution, ultrasonically dispersing for 23 min, standing at room temperature for 3.2 h, and then fully drying at 87° C. for 7.2 h under vacuum, and soaking the dried polyimide in a 14 wt.% toluene solution for 2.8 h to dissolve and remove the polymethyl methacrylate microspheres, washing, and vacuum drying at 159° C. for 5.1 h to obtain a modified polyimide;

[0137] Step S3, after mixing and melting 90g of modified polyimide, 28g of low-density polyethylene, and 24g of epoxy resin at 375°C, 8.1g of pterostilbene phosphate flame retardant, 7.2g of modified flame retardant, 2.1g of antioxidant 1010, 1.7g of epoxy soybean oil, 2.6g of stearic acid, 2.3g of glass fiber, and 37g of diphenylmethanetetracarboxylic anhydride are added in sequence and mixed evenly, and then extruded and coated on the surface of the copper wire core to obtain a fireproof and waterproof modified tunnel lighting wire.

[0138] Example 6

[0139] This embodiment provides a method for preparing a fireproof and waterproof modified tunnel lighting wire, such as Figure 1 As shown, the preparation method specifically comprises the following steps:

[0140] Step A, 41 mmol of pterostilbene and 152 mmol of sodium carbonate are added to 440 mL of tetrahydrofuran in sequence, the temperature is raised to 83° C. and stirred at 370 rpm for 26 min to obtain a mixture, 113 mmol of triphenyl phosphate is added to the mixture and fully reacted for 13.7 h, after the reaction is completed, the mixture is cooled to room temperature, filtered and washed, and then placed at 57° C. for vacuum drying for 27 h to obtain a pterostilbene phosphate flame retardant;

[0141] Step B, add 5.3g of 2-amino-5-methyl-1,3,4-thiadiazole to 155mL of anhydrous ethanol, raise the temperature to 92°C and keep stirring at 340rpm for 2.5h, then add 2.2g of p-hydroxybenzaldehyde, continue the reaction for 13.1h, then add 8.3g of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, continue the reaction for 17.0h, cool to room temperature after the reaction is completed, filter and wash, and then place under vacuum at 57°C for 11.6h to obtain a modified flame retardant;

[0142] Step S1, adding 26 mmol 4,4'-diaminodiphenyl ether and 4.0 mmol octylamine to 77 mL N-methylpyrrolidone, heating to 86°C and stirring at 330 rpm for 74 min to obtain a modified diamine solution, then adding 28 mmol pyromellitic anhydride to another 116 mL N-methylpyrrolidone, stirring at 240 rpm for 41 min to obtain a dianhydride solution, adding the modified diamine solution to the dianhydride solution, heating to 82°C under nitrogen protection for sufficient reaction for 4.7 h to obtain a polyimide solution;

[0143] Step S2, adding 28 mL of polymethyl methacrylate microsphere solution to the polyimide solution, ultrasonically dispersing for 26 min, standing at room temperature for 3.6 h, and then fully drying at 88° C. for 7.7 h under vacuum, and soaking the dried polyimide in 18 wt.% toluene solution for 2.1 h to dissolve and remove the polymethyl methacrylate microspheres, washing, and vacuum drying at 155° C. for 5.3 h to obtain a modified polyimide;

[0144] Step S3, after 92g of modified polyimide, 24g of low-density polyethylene, and 21g of epoxy resin are mixed and melted at 371°C, 8.6g of pterostilbene phosphate flame retardant, 7.5g of modified flame retardant, 2.4g of antioxidant 1076, 1.9g of glycerol, 2.2g of calcium stearate, 2.8g of talc, and 34g of diphenylmethanetetracarboxylic anhydride are added in sequence and mixed evenly, and then extruded and coated on the surface of the copper wire core to obtain a fireproof and waterproof modified tunnel lighting wire.

[0145] Comparative Example 1

[0146] This comparative example provides a method for preparing a fireproof and waterproof modified tunnel lighting wire, which differs from Example 1 in that the amount of triphenyl phosphate in step A is adjusted to 136 mmol. Compared with Example 1, the amount of triphenyl phosphate in this comparative example is increased by 30 mmol, and the increased amount of the substance is deducted from the equal proportion of pterostilbene and sodium carbonate, so that the amount ratio of the substances between the other components except triphenyl phosphate remains unchanged, and the other process parameters and operating conditions are exactly the same as those in Example 1.

[0147] Comparative Example 2

[0148] This comparative example provides a method for preparing a fireproof and waterproof modified tunnel lighting wire, which differs from Example 1 in that the amount of triphenyl phosphate in step A is adjusted to 76 mmol. Compared with Example 1, the amount of triphenyl phosphate in this comparative example is reduced by 30 mmol, and the reduced amount of substance is added to pterostilbene and sodium carbonate in equal proportion, so that the amount ratio of the substances between the other components except triphenyl phosphate remains unchanged, and the other process parameters and operating conditions are exactly the same as those in Example 1.

[0149] Comparative Example 3

[0150] This comparative example provides a method for preparing a fireproof and waterproof modified tunnel lighting wire, which differs from Example 1 in that the mass of p-hydroxybenzaldehyde in step B is adjusted to 3.3 g. Compared with Example 1, p-hydroxybenzaldehyde in this comparative example is increased by 1 g, and the increased mass is deducted from 2-amino-5-methyl-1,3,4-thiadiazole and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide in equal proportion, so that the molar ratio of the components other than p-hydroxybenzaldehyde remains unchanged, and the other process parameters and operating conditions are exactly the same as those in Example 1.

[0151] Comparative Example 4

[0152] This comparative example provides a method for preparing fireproof and waterproof modified tunnel lighting wires, which differs from Example 1 in that the mass of p-hydroxybenzaldehyde in step B is adjusted to 1.3 g. Compared with Example 1, the p-hydroxybenzaldehyde in this comparative example is reduced by 1 g, and the reduced mass is added in equal proportion to 2-amino-5-methyl-1,3,4-thiadiazole and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, so that the molar ratio of the components other than p-hydroxybenzaldehyde remains unchanged, and the other process parameters and operating conditions are exactly the same as those in Example 1.

[0153] The limiting oxygen index of the materials prepared in Examples 1-6 and Comparative Examples 1-4 was tested according to the national standard GB / T 2406.2-2009; the flame retardant properties of the materials prepared in Examples 1-6 and Comparative Examples 1-4 were tested according to GB / T 2408-2021; the maximum smoke density and tensile strength of the materials prepared in Examples 1-6 and Comparative Examples 1-4 were tested according to the national standard GB / T 32129-2015. The test results are shown in Table 1.

[0154] Table 1 Test results of fireproof and waterproof modified tunnel lighting wires of Examples 1-6 and Comparative Examples 1-4

[0155] From the data of Example 1, Comparative Example 1 and Comparative Example 2, it can be seen that the limiting oxygen index, flame retardant effect, tensile strength and elongation at break of Comparative Example 1 are lower than those of Example 1, and the maximum smoke density is higher than that of Example 1; the limiting oxygen index, flame retardant effect, tensile strength and elongation at break of Comparative Example 2 are lower than those of Example 1, and the maximum smoke density is higher than that of Example 1. This is because the excess of triphenyl phosphate in Comparative Example 1 causes the phenolic hydroxyl groups of pterostilbene to overreact, generating more phosphate groups. Although these phosphate groups have a positive effect on flame retardancy, overreaction may cause the phosphate groups to present too high a concentration in the final polymer. Excessive triphenyl phosphate may lead to the release of more gas, thereby increasing the generation of smoke, which is not conducive to the low smoke characteristics, and may also lead to the formation of excessive carbonization products, reducing the flame retardant effect of the material. In Comparative Example 2, triphenyl phosphate is insufficient, the reaction between pterostilbene and triphenyl phosphate cannot be fully carried out, the formation of flame retardant groups is insufficient, thereby affecting the flame retardant effect of the material, and the flame retardant products formed are limited, resulting in the inability to effectively control the generation of smoke during flame propagation.

[0156] From the data of Example 1, Comparative Example 3 and Comparative Example 4, it can be seen that the limiting oxygen index, flame retardant effect, tensile strength and elongation at break of Comparative Example 3 are lower than those of Example 1, and the maximum smoke density is higher than that of Example 1; this is because the excessive p-hydroxybenzaldehyde in Comparative Example 3 causes excessive nucleophilic substitution reaction between phenolic hydroxyl groups and thiadiazole substances to generate more imine structures. Although there is a partial flame retardant effect, the excessive phenolic hydroxyl groups cause too many organic components to appear in the material, reducing the smoke suppression performance of the material. In Comparative Example 4, the amount of p-hydroxybenzaldehyde is insufficient, and the number of phenolic hydroxyl groups is insufficient, resulting in insufficient imine structures formed, thereby failing to form an effective flame retardant layer, resulting in a decrease in the flame retardant effect of the material. At the same time, the phenolic groups can form a protective layer through reactions such as dehydration and carbonization during combustion to inhibit the spread of flames and the generation of smoke. If the phenolic hydroxyl groups are insufficient, the organic gas and smoke generated during the combustion process will increase.

[0157] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention are within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing a fireproof and waterproof modified tunnel lighting wire, characterized in that: The preparation method is: Step S1, adding a diamine monomer and octylamine to a first portion of N-methylpyrrolidone, heating to a first temperature and continuously stirring to obtain a modified diamine solution, then adding a dianhydride monomer to a second portion of N-methylpyrrolidone, stirring evenly to obtain a dianhydride solution, adding the modified diamine solution to the dianhydride solution, heating to the first temperature under nitrogen protection to fully react, and obtaining a polyimide solution; Step S2, adding a polymethyl methacrylate microsphere solution to a polyimide solution, uniformly dispersing by ultrasonication, standing at room temperature, and fully drying at a first temperature under a vacuum state, soaking the dried polyimide in a toluene solution to dissolve and remove the polymethyl methacrylate microspheres, washing, and drying under vacuum at a second temperature to obtain a modified polyimide; Step S3, after the modified polyimide, low-density polyethylene and epoxy resin are mixed and melted at the third temperature, pterostilbene phosphate flame retardant, modified flame retardant, antioxidant, plasticizer, lubricant, inorganic filler and diphenylmethane tetracarboxylic anhydride are added in sequence and mixed evenly, and after extrusion, they are coated on the surface of the copper wire core to obtain a fireproof and waterproof modified tunnel lighting wire.

2. The method for preparing a fireproof and waterproof modified tunnel lighting wire according to claim 1, characterized in that: In step S1, The diamine monomer is 4,4'-diaminodiphenyl ether, and the amount of the substance is 20-30 mmol; The amount of octylamine is 10-20% of the amount of diamine monomer; The volume of the first portion of N-methylpyrrolidone is 60-80 mL; The first temperature is 80-90°C; The dianhydride monomer is pyromellitic anhydride, the amount of the substance is 20-30mmol; The volume of the second portion of N-methylpyrrolidone is 100-120 mL; The reaction time at the first temperature is 4-5h.

3. The method for preparing a fireproof and waterproof modified tunnel lighting wire according to claim 1, characterized in that: In step S2, The volume of the polymethyl methacrylate microsphere solution is 20-30 mL, the mass fraction is 2.5 wt.%, and the particle size of the polymethyl methacrylate microsphere is 30 nm; The ultrasound time is 20-30min; The standing time at room temperature is 3-4h; The first temperature vacuum drying time is 6-8h; The mass fraction of the toluene solution is 10-20wt.%, and the volume is 200-300mL; The soaking time is 2-3h; The second temperature is 150-160°C; The time of vacuum drying at the second temperature is 4-6 hours.

4. The method for preparing a fireproof and waterproof modified tunnel lighting wire according to claim 1, characterized in that: In step S3, The mass of the modified polyimide is 80-100g; The mass of the low-density polyethylene is 20-30g; The mass of the epoxy resin is 20-30g; The third temperature is 350-380°C; The mass of the pterostilbene phosphate flame retardant is 5-10g; The mass of the modified flame retardant is 5-10g; The antioxidant is any one of antioxidant 168, antioxidant 1010 and antioxidant 1076; The weight of the antioxidant is 1-3g; The plasticizer is any one of glycerol and epoxidized soybean oil; The mass of the plasticizer is 1-3g; The lubricant is any one of stearic acid, zinc stearate and calcium stearate; The mass of the lubricant is 1-3g; The inorganic filler is any one of glass fiber and talcum powder; The mass of the inorganic filler is 1-3g; The mass of the diphenylmethanetetracarboxylic anhydride is 30-50g.

5. The method for preparing a fireproof and waterproof modified tunnel lighting wire according to claim 1, characterized in that: The preparation method of the pterostilbene phosphate flame retardant is: Step A, adding pterostilbene and sodium carbonate to tetrahydrofuran in sequence, heating to a first temperature and continuously stirring to obtain a mixture, then adding triphenyl phosphate to the mixture and reacting sufficiently, cooling to room temperature after the reaction, filtering and washing, and then vacuum drying at a fourth temperature to obtain a pterostilbene phosphate flame retardant.

6. The method for preparing a fireproof and waterproof modified tunnel lighting wire according to claim 5, characterized in that: The amount of the pterostilbene substance is 40-50 mmol; The amount of sodium carbonate is 140-160 mmol; The volume of tetrahydrofuran is 400-500mL; The amount of triphenyl phosphate is 100-120 mmol; The reaction time of adding triphenyl phosphate to the mixture is 12-14h; The fourth temperature is 50-60°C; The vacuum drying time at the fourth temperature is 20-30 hours.

7. The method for preparing a fireproof and waterproof modified tunnel lighting wire according to claim 1, characterized in that: The modified flame retardant preparation method is: Step B, adding 2-amino-5-methyl-1,3,4-thiadiazole to anhydrous ethanol, heating to the fifth temperature and keeping stirring, then adding p-hydroxybenzaldehyde, and adding 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide after continuous reaction, and continuing the reaction. After the reaction is completed, cooling to room temperature, filtering and washing, and then placing under vacuum at the fourth temperature to obtain a modified flame retardant.

8. The method for preparing a fireproof and waterproof modified tunnel lighting wire according to claim 7, characterized in that: The mass of the 2-amino-5-methyl-1,3,4-thiadiazole is 5-6 g; The volume of the anhydrous ethanol is 150-170 mL; The fifth temperature is 90-100° C.; The mass of the p-hydroxybenzaldehyde is 2-3g; The reaction time after adding p-hydroxybenzaldehyde is 12-14 hours.

9. The method for preparing a fireproof and waterproof modified tunnel lighting wire according to claim 7, characterized in that: The mass of the 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is 8-9 g; The reaction time after adding 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is 16-18h; The vacuum drying time is 10-12 hours.

10. A fireproof and waterproof modified tunnel lighting wire prepared according to the preparation method according to any one of claims 1 to 9.

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