Flame-retardant high-strength insulating material and preparation process thereof

Abstract

The invention relates to the technical field of insulating materials, in particular to a flame-retardant high-strength insulating material and a preparation process thereof. The insulating material comprises the following components in parts by weight: 50-60 parts of polyvinyl chloride, 20-40 parts of crosslinked polyethylene, 10-15 parts of an ethylene-vinyl acetate copolymer, 20-40 parts of a flame retardant, 5-15 parts of talcum powder, 10-20 parts of calcium carbonate, 6-12 parts of a compatilizer and 3-8 parts of an antioxidant. The flame retardant is prepared by taking ammonium polyphosphate as an acid source, polydopamine as a charring agent and modified graphene oxide as a reinforcing agent, the flame retardant is added into polyvinyl chloride and a crosslinked polyethylene insulating material base material, and combined with the combined action of an ethylene-vinyl acetate copolymer, talcum powder, calcium carbonate, a compatilizer and an antioxidant, the flame retardant property of the insulating material base material is improved, and the flame retardant property of the insulating material base material is improved. The prepared insulating material not only has excellent mechanical property, but also has excellent flame retardant property, so that the service life of the material is prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of insulating materials, in particular to a flame retardant high-strength insulating material and a preparation process thereof. Background Art

[0002] With the rapid development of industrialization and modern technology, the demand for various high-strength insulation materials in the fields of electrical, electronic, aerospace and construction is increasing. These materials are not only required to have excellent insulation properties, but also flame retardancy to ensure safety. Therefore, it is particularly important to develop an insulation material with both high strength and excellent flame retardancy.

[0003] At present, many flame retardants are prone to migration in high temperature environments, causing the flame retardant properties of the material to weaken over time, thus failing to provide lasting safety protection for the equipment; in the process of adding flame retardants, the mechanical strength of the material is often reduced, which makes it impossible to meet the requirements for high-strength insulation materials. The difference in compatibility between the flame retardant and the matrix may also further weaken the mechanical properties of the material.

[0004] Therefore, we propose a flame retardant high-strength insulating material and a preparation process thereof. Summary of the invention

[0005] The object of the present invention is to provide a flame retardant high-strength insulating material and a preparation process thereof, so as to solve the problems raised in the above background technology.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] A preparation process of a flame retardant high-strength insulating material comprises the following steps:

[0008] Step S1: ultrasonically dispersing the modified graphene oxide in anhydrous ethanol, adding modified ammonium polyphosphate, continuing ultrasonic dispersion for 15-30 minutes, and obtaining a flame retardant after rotary evaporation, washing, and drying;

[0009] Step S2: uniformly mix polyvinyl chloride, cross-linked polyethylene, ethylene-vinyl acetate copolymer, flame retardant, talcum powder, calcium carbonate, compatibilizer and antioxidant to obtain a mixture; put the mixture into an extrusion device for mixing, extruding and granulating to obtain an insulating material.

[0010] Furthermore, the insulating material includes the following components by weight: 50-60 parts of polyvinyl chloride, 20-40 parts of cross-linked polyethylene, 10-15 parts of ethylene-vinyl acetate copolymer, 20-40 parts of flame retardant, 5-15 parts of talc, 10-20 parts of calcium carbonate, 6-12 parts of compatibilizer, and 3-8 parts of antioxidant.

[0011] Furthermore, the flame retardant includes the following components by weight: 5-10 parts of modified graphene oxide and 15-30 parts of modified ammonium polyphosphate.

[0012] Furthermore, in step S1, the mass ratio of modified graphene oxide to anhydrous ethanol is 1:(90-110).

[0013] Furthermore, the preparation method of the modified graphene oxide is as follows:

[0014] Step (1): 2-chloro-4,6-diamino-1,3,5-triazine and anhydrous ethanol are mixed evenly, 2,3-dimercaptosuccinic acid and KOH methanol solution are added dropwise, the dripping is completed within 20-40 minutes, the mixture is reacted at 70-80° C. for 24-28 hours, and a thiol-containing compound is obtained after filtering, washing and drying; under nitrogen protection, vanillin, a thiol-containing compound and anhydrous ethanol are mixed evenly, and the mixture is reacted at 65-75° C. for 8-10 hours, DOPO is added, and the reaction is continued for 10-12 hours, and modified DOPO is obtained after rotary evaporation, washing and drying;

[0015] Step (2): mixing a graphene oxide aqueous solution, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide, and ultrasonically dispersing for 30-60 minutes, adding a mixed solution of oleylamine, ethanol and deionized water, and continuing ultrasonically dispersing for 2-3 hours, stirring for 22-24 hours, and obtaining graphene oxide containing double bonds after centrifugation, filtration and drying;

[0016] Step (3): The double-bond-containing graphene oxide, modified DOPO and a photoinitiator are uniformly mixed, and after ultraviolet irradiation, modified graphene oxide is obtained.

[0017] In the above technical scheme, 2-chloro-4,6-diamino-1,3,5-triazine is used as a raw material to react with the thiol in 2,3-dimercaptosuccinic acid under strong alkaline conditions to obtain a thiol-containing compound having a triazine structure and an amino group; then vanillin, the thiol-containing compound and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) are used to undergo a nucleophilic addition reaction to obtain a modified DOPO having N, S, and P elements; then a long-chain aliphatic oleylamine is grafted onto graphene oxide to obtain double-bond graphene oxide, thereby increasing its compatibility and dispersibility with other components; finally, the remaining thiol in the modified DOPO is used to undergo a thiol-ene click reaction with the double-bond graphene oxide to obtain a modified graphene oxide having excellent mechanical properties and flame retardant properties.

[0018] Furthermore, in the step (1), the mass ratio of 2-chloro-4,6-diamino-1,3,5-triazine, 2,3-dimercaptosuccinic acid and anhydrous ethanol is 1:(1.3-1.5):(15-20).

[0019] Furthermore, in step (1), the concentration of the KOH methanol solution is 2-3 mol / L, and the amount thereof is 1.2-1.5 times the mass of 2,3-dimercaptosuccinic acid.

[0020] Furthermore, in the step (1), the mass ratio of vanillin, thiol-containing compound, anhydrous ethanol and DOPO is 1:(2.0-2.5):(5-7):(1.4-1.6).

[0021] Furthermore, in the step (2), the mass ratio of the graphene oxide aqueous solution, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide is 1:(0.012-0.015):(0.010-0.012), and the concentration of the graphene oxide aqueous solution is 10 mg / mL.

[0022] Furthermore, in step (2), the mass ratio of oleylamine to ethanol and deionized water is 1:(15-20):(10-20), and the mass of oleylamine is 1-3% of the mass of the graphene oxide aqueous solution.

[0023] Furthermore, in the step (3), the mass ratio of double-bond graphene oxide, modified DOPO and photoinitiator is 1:(2-4):(0.3-0.5).

[0024] Furthermore, the photoinitiator is 2-hydroxy-2-methylpropiophenone.

[0025] Furthermore, the process conditions of the ultraviolet irradiation are: irradiation wavelength 360-400nm, irradiation time 0.5-2.0h, irradiation intensity 20-35mW / cm 2 .

[0026] Furthermore, the preparation method of the modified ammonium polyphosphate is as follows:

[0027] The ammonium polyphosphate, dopamine hydrochloride and deionized water are mixed evenly, Tris-HCl is added, the pH value of the system is adjusted to 8.5 with ammonia water, and the mixture is stirred for 24-36 hours. After centrifugation, washing and drying, the modified ammonium polyphosphate is obtained.

[0028] Furthermore, the mass ratio of the ammonium polyphosphate, dopamine hydrochloride, Tris-HCl and deionized water is 1:(0.1-0.2):(0.05-0.10):(15-20).

[0029] In the above technical scheme, under weak alkaline conditions, dopamine will oxidize and self-polymerize to form polydopamine, which can be deposited on the surface of almost any material. The polyphenol structure of polydopamine is not only a good carbon-forming agent, but also its catechol has a good free radical capture effect during the combustion process, thereby inhibiting the combustion reaction and enhancing the flame retardant properties.

[0030] Furthermore, the compatibilizer is at least one of hydrogenated styrene-butadiene-styrene copolymer grafted with glycidyl methacrylate, ethylene-methyl acrylate grafted with glycidyl methacrylate, and styrene-acrylonitrile copolymer grafted with glycidyl methacrylate.

[0031] Furthermore, the antioxidant is antioxidant 1010.

[0032] Furthermore, the temperature of zone 1 of the extrusion equipment is 285-305°C, the temperature of zone 2 is 295-315°C, the temperature of zone 3 is 295-315°C, the temperature of zone 4 is 300-320°C, and the temperature of zone 5 is 290-300°C.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] 1. A flame retardant high-strength insulating material and a preparation process thereof of the present invention, wherein 2-chloro-4,6-diamino-1,3,5-triazine is reacted with 2,3-dimercaptosuccinic acid under strong alkaline conditions to obtain a thiol-containing compound, which not only has the stability of the triazine structure and has an excellent carbonization effect, but is also rich in amino and thiol groups, which is convenient for subsequent chemical reactions; vanillin, the thiol-containing compound and DOPO are reacted to obtain a modified DOPO, wherein the nitrogen, sulfur and phosphorus elements in the modified DOPO can enhance its flame retardant properties, form an effective carbonization layer, slow down the spread of flame, and have a good effect on the thermal stability and The flame retardant mechanism is positively affected; long-chain oleylamine is grafted onto graphene oxide to obtain double-bonded graphene oxide, which improves the hydrophobicity and mechanical properties of the material, makes graphene oxide less likely to agglomerate, improves the dispersibility of graphene oxide, and thus improves the strength and toughness of the material; finally, the remaining thiol groups in the modified DOPO undergo a thiol-ene click reaction with the double-bonded graphene oxide to form a strong covalent bond, so that the modified DOPO and graphene oxide are more effectively combined, thereby improving the overall performance of the composite material and obtaining modified graphene oxide with excellent mechanical properties and flame retardant properties.

[0035] 2. A flame-retardant high-strength insulating material and a preparation process thereof of the present invention, using ammonium polyphosphate as an acid source, polydopamine as a carbonizing agent, and modified graphene oxide as a reinforcing agent, to prepare a core-shell flame retardant integrating flame retardancy and reinforcing effects. By depositing polydopamine on the surface of ammonium polyphosphate, and then utilizing hydrogen bonds and π-π conjugation forces between modified graphene oxide and polydopamine, the modified graphene oxide is assembled on the surface of polydopamine, thereby achieving an effective combination of ammonium polyphosphate and modified graphene oxide, and the formed core-shell structure can effectively inhibit the spread of flames, while reducing the heat release rate of the material, increasing the fire resistance level of the material, and further improving the flame retardant effect.

[0036] 3. A flame-retardant high-strength insulating material and its preparation process of the present invention, with polyvinyl chloride and cross-linked polyethylene as the base material of the insulating material, ethylene-vinyl acetate copolymer, flame retardant, talcum powder, calcium carbonate, compatibilizer and antioxidant are added to obtain the insulating material. The material has excellent comprehensive properties such as electrical insulation, flame retardancy, heat resistance, impact resistance, tensile strength, etc. Among them, the polyvinyl chloride resin is polymerized with the cross-linked polyethylene resin with excellent electrical insulation effect and large current carrying capacity, which can effectively improve the electrical insulation effect and load capacity of the composite material; the addition of ethylene-vinyl acetate copolymer further improves the flexibility and mechanical damage resistance of the material, and the flame retardant ensures the safety in high temperature and flame environment; talcum powder and calcium carbonate are used as fillers, which not only reduce the cost of the material, but also enhance its rigidity and heat resistance, and the use of compatibilizer and antioxidant ensures the uniformity and long-term stability of each component. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] In this embodiment, graphene oxide: model DN-20DY, sourced from Zhejiang Zhitai Nanowei New Materials Co., Ltd.; ammonium polyphosphate: model A823395, sourced from Shanghai McLean Biochemical Technology Co., Ltd.; polyvinyl chloride: model SG-3; cross-linked polyethylene: British AEI, brand SX-0670; ethylene-vinyl acetate copolymer: model P815474, sourced from Shanghai McLean Biochemical Technology Co., Ltd.; talcum powder: particle size 3000 mesh; calcium carbonate: particle size 1250 mesh; compatibilizer: ethylene-methyl acrylate grafted glycidyl methacrylate, E-MA-GMA, brand BF-7L; antioxidant: antioxidant 1010.

[0039] In the following examples and comparative examples, 1 part is equal to 10 g.

[0040] Embodiment 1: A process for preparing a flame retardant high-strength insulating material, comprising the following process:

[0041] Step S1: ultrasonically dispersing 5 parts of modified graphene oxide in 450 parts of anhydrous ethanol, adding 15 parts of modified ammonium polyphosphate and mixing evenly, and obtaining a flame retardant after rotary evaporation, washing and drying;

[0042] Step S2: 50 parts of polyvinyl chloride, 20 parts of cross-linked polyethylene, 10 parts of ethylene-vinyl acetate copolymer, 20 parts of flame retardant, 5 parts of talc, 10 parts of calcium carbonate, 6 parts of compatibilizer and 3 parts of antioxidant are mixed uniformly to obtain a mixture; the mixture is put into an extrusion device for mixing, extrusion and granulation to obtain an insulating material (the temperature of the first zone of the extrusion device is 285° C., the temperature of the second zone is 295° C., the temperature of the third zone is 295° C., the temperature of the fourth zone is 300° C., and the temperature of the fifth zone is 290° C.);

[0043] The preparation method of modified graphene oxide is as follows:

[0044] Step (1): 16 parts of 2-chloro-4,6-diamino-1,3,5-triazine and 240 parts of anhydrous ethanol are mixed evenly, 20.8 parts of 2,3-dimercaptosuccinic acid and 25 parts of 2 mol / L KOH methanol solution are added dropwise, and the mixture is added for 20 minutes. The mixture is reacted at 70° C. for 24 hours. After filtering, washing and drying, a thiol-containing compound is obtained. Under nitrogen protection, 10 parts of vanillin, 20 parts of the thiol-containing compound and 50 parts of anhydrous ethanol are mixed evenly, and the mixture is reacted at 65° C. for 8 hours. Then 14 parts of DOPO are added and the mixture is reacted for 10 hours. After rotary evaporation, washing and drying, a modified DOPO is obtained.

[0045] Step (2): 500 parts of a 10 mg / mL graphene oxide aqueous solution, 6 parts of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 5 parts of N-hydroxysuccinimide were mixed, and ultrasonically dispersed for 30 minutes, and a mixed solution of 5 parts of oleylamine, 225 parts of ethanol and 150 parts of deionized water was added, and ultrasonic dispersion was continued for 2 hours, and stirred for 22 hours. After centrifugation, filtration and drying, graphene oxide containing double bonds was obtained;

[0046] Step (3): 5 parts of double-bond graphene oxide, 10 parts of modified DOPO and 1.5 parts of photoinitiator were mixed evenly and irradiated with ultraviolet light (irradiation wavelength 360nm, irradiation time 0.5h, irradiation intensity 20mW / cm 2 ), to obtain modified graphene oxide;

[0047] The preparation method of modified ammonium polyphosphate is as follows:

[0048] 20 parts of ammonium polyphosphate, 2 parts of dopamine hydrochloride and 300 parts of deionized water were mixed evenly, 1 part of Tris-HCl was added, the pH of the system was adjusted to 8.5 with ammonia water, and the mixture was stirred for 24 hours. After centrifugation, washing and drying, the modified ammonium polyphosphate was obtained.

[0049] Embodiment 2: A process for preparing a flame retardant high-strength insulating material, comprising the following process:

[0050] Step S1: ultrasonically dispersing 10 parts of modified graphene oxide in 1000 parts of anhydrous ethanol, adding 20 parts of modified ammonium polyphosphate and mixing evenly, and obtaining a flame retardant after rotary evaporation, washing and drying;

[0051] Step S2: 55 parts of polyvinyl chloride, 30 parts of cross-linked polyethylene, 12 parts of ethylene-vinyl acetate copolymer, 30 parts of flame retardant, 10 parts of talc, 15 parts of calcium carbonate, 8 parts of compatibilizer and 5 parts of antioxidant are mixed uniformly to obtain a mixture; the mixture is put into an extrusion device for mixing, extrusion and granulation to obtain an insulating material (the temperature of the first zone of the extrusion device is 290° C., the temperature of the second zone is 300° C., the temperature of the third zone is 305° C., the temperature of the fourth zone is 310° C., and the temperature of the fifth zone is 295° C.);

[0052] The preparation method of modified graphene oxide is as follows:

[0053] Step (1): 34 parts of 2-chloro-4,6-diamino-1,3,5-triazine and 620 parts of anhydrous ethanol are mixed evenly, 48 parts of 2,3-dimercaptosuccinic acid and 62 parts of 2.5 mol / L KOH methanol solution are added dropwise, and the mixture is added for 30 minutes. The mixture is reacted at 75° C. for 26 hours. After filtering, washing and drying, a thiol-containing compound is obtained. Under nitrogen protection, 20 parts of vanillin, 48 parts of a thiol-containing compound and 120 parts of anhydrous ethanol are mixed evenly, and the mixture is reacted at 70° C. for 9 hours. Then, 30 parts of DOPO are added and the mixture is reacted for 11 hours. After rotary evaporation, washing and drying, a modified DOPO is obtained.

[0054] Step (2): 1000 parts of a 10 mg / mL graphene oxide aqueous solution, 13 parts of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 11 parts of N-hydroxysuccinimide were mixed, and ultrasonic dispersion was performed for 40 minutes. A mixed solution of 20 parts of oleylamine, 720 parts of ethanol and 600 parts of deionized water was added, and ultrasonic dispersion was continued for 2.5 hours. The mixture was stirred for 23 hours, and after centrifugation, filtration and drying, graphene oxide containing double bonds was obtained;

[0055] Step (3): 10 parts of double-bond graphene oxide, 30 parts of modified DOPO and 4 parts of photoinitiator were mixed evenly and irradiated with ultraviolet light (irradiation wavelength 380nm, irradiation time 1h, irradiation intensity 30mW / cm 2 ), to obtain modified graphene oxide;

[0056] The preparation method of modified ammonium polyphosphate is as follows:

[0057] 20 parts of ammonium polyphosphate, 3 parts of dopamine hydrochloride and 360 parts of deionized water were mixed evenly, 1.6 parts of Tris-HCl were added, the pH of the system was adjusted to 8.5 with ammonia water, and the mixture was stirred for 30 hours. After centrifugation, washing and drying, modified ammonium polyphosphate was obtained.

[0058] Embodiment 3: A process for preparing a flame retardant high-strength insulating material, comprising the following process:

[0059] Step S1: ultrasonically dispersing 15 parts of modified graphene oxide in 1650 parts of anhydrous ethanol, adding 25 parts of modified ammonium polyphosphate and mixing evenly, and obtaining a flame retardant after rotary evaporation, washing and drying;

[0060] Step S2: 60 parts of polyvinyl chloride, 40 parts of cross-linked polyethylene, 15 parts of ethylene-vinyl acetate copolymer, 40 parts of flame retardant, 15 parts of talc, 20 parts of calcium carbonate, 12 parts of compatibilizer and 8 parts of antioxidant are mixed uniformly to obtain a mixture; the mixture is put into an extrusion device for mixing, extrusion and granulation to obtain an insulating material (the temperature of the first zone of the extrusion device is 305° C., the temperature of the second zone is 315° C., the temperature of the third zone is 315° C., the temperature of the fourth zone is 320° C., and the temperature of the fifth zone is 300° C.);

[0061] The preparation method of modified graphene oxide is as follows:

[0062] Step (1): 67 parts of 2-chloro-4,6-diamino-1,3,5-triazine and 1340 parts of anhydrous ethanol are mixed evenly, 100.5 parts of 2,3-dimercaptosuccinic acid and 3 mol / L KOH methanol solution are added dropwise, the dripping is completed in 40 minutes, the mixture is reacted at 80° C. for 28 hours, and a thiol-containing compound is obtained after filtering, washing and drying; under nitrogen protection, 40 parts of vanillin, 100 parts of a thiol-containing compound and 280 parts of anhydrous ethanol are mixed evenly, the mixture is reacted at 75° C. for 10 hours, 64 parts of DOPO are added, the reaction is continued for 12 hours, and modified DOPO is obtained after rotary evaporation, washing and drying;

[0063] Step (2): 1500 parts of a 10 mg / mL graphene oxide aqueous solution, 22.5 parts of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 18 parts of N-hydroxysuccinimide were mixed, and ultrasonic dispersion was performed for 60 minutes. A mixed solution of 45 parts of oleylamine, 900 parts of ethanol and 900 parts of deionized water was added, and ultrasonic dispersion was continued for 3 hours. Stirring was performed for 24 hours. After centrifugation, filtration and drying, graphene oxide containing double bonds was obtained.

[0064] Step (3): 15 parts of double-bond graphene oxide, 60 parts of modified DOPO and 7.5 parts of photoinitiator were mixed evenly and irradiated with ultraviolet light (irradiation wavelength 360-400nm, irradiation time 2.0h, irradiation intensity 35mW / cm 2 ), to obtain modified graphene oxide;

[0065] The preparation method of modified ammonium polyphosphate is as follows:

[0066] 25 parts of ammonium polyphosphate, 5 parts of dopamine hydrochloride and 500 parts of deionized water were mixed evenly, 2.5 parts of Tris-HCl were added, the pH of the system was adjusted to 8.5 with ammonia water, and the mixture was stirred for 36 hours. After centrifugation, washing and drying, modified ammonium polyphosphate was obtained.

[0067] Comparative Example 1: A process for preparing a flame-retardant high-strength insulating material, comprising the following processes:

[0068] Compared with Example 2, in Comparative Example 1, the modified ammonium polyphosphate is replaced with ammonium polyphosphate of the same mass, and the other steps are the same as those of Example 2.

[0069] Comparative Example 2: A process for preparing a flame-retardant high-strength insulating material, comprising the following processes:

[0070] Compared with Example 2, the mass ratio of modified graphene oxide to modified ammonium polyphosphate in Comparative Example 2 is 3:1, and the other steps are the same as those in Example 2.

[0071] Comparative Example 3: A process for preparing a flame retardant high-strength insulating material, comprising the following processes:

[0072] Compared with Example 2, in Comparative Example 3, the modified graphene oxide is replaced with graphene oxide of the same mass, and the other steps are the same as those of Example 2.

[0073] Comparative Example 4: A process for preparing a flame retardant high-strength insulating material, comprising the following processes:

[0074] The preparation method of modified graphene oxide is as follows:

[0075] Step (1): 34 parts of 2-chloro-4,6-diamino-1,3,5-triazine and 620 parts of anhydrous ethanol are mixed evenly, 48 parts of 2,3-dimercaptosuccinic acid and 62 parts of 2.5 mol / L KOH methanol solution are added dropwise, and the mixture is added for 30 minutes. The mixture is reacted at 75° C. for 26 hours. After filtering, washing and drying, a thiol-containing compound is obtained. Under nitrogen protection, 20 parts of vanillin, 48 parts of a thiol-containing compound and 120 parts of anhydrous ethanol are mixed evenly, and the mixture is reacted at 70° C. for 9 hours. Then, 30 parts of DOPO are added and the mixture is reacted for 11 hours. After rotary evaporation, washing and drying, a modified DOPO is obtained.

[0076] Step (2): 1000 parts of a 10 mg / mL graphene oxide aqueous solution, 13 parts of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 11 parts of N-hydroxysuccinimide were mixed, and ultrasonic dispersion was performed for 40 minutes. A mixed solution of 20 parts of oleylamine, 720 parts of ethanol and 600 parts of deionized water was added, and ultrasonic dispersion was continued for 2.5 hours. The mixture was stirred for 23 hours, and after centrifugation, filtration and drying, graphene oxide containing double bonds was obtained;

[0077] Step (3): 10 parts of double-bond graphene oxide, 5 parts of modified DOPO and 4 parts of photoinitiator were mixed evenly and irradiated with ultraviolet light (irradiation wavelength 380nm, irradiation time 1h, irradiation intensity 30mW / cm 2 ), to obtain modified graphene oxide;

[0078] Compared with Example 2, the mass ratio of double-bond graphene oxide to modified DOPO in Comparative Example 4 is 1:0.5; the other steps are the same as those in Example 2.

[0079] Experiment: Take the insulating materials obtained in Examples 1-3 and Comparative Examples 1-4, prepare samples, test their properties respectively and record the test results:

[0080] The tensile strength was measured according to GB / T 1040.3-2006 “Test for tensile properties of plastics”, the sample size was 150 mm × 15 mm × 1 mm, and the tensile speed was 100 mm / min.

[0081] The oxygen index was determined according to GB / T 2406 standard, and the sample size was 125 mm × 6.5 mm × 3 mm.

[0082] Test Results

[0083] Tensile strength / MPa Oxygen index / % Example 1 16.4 30 Example 2 16.6 31 Example 3 16.5 30 Comparative Example 1 15.2 26 Comparative Example 2 15.8 27 Comparative Example 3 14.7 24 Comparative Example 4 16.0 28

[0084] According to the data in the above table, we can clearly draw the following conclusions:

[0085] 1. Compared with Examples 1-3, the tensile strength and oxygen index of the product obtained in Comparative Example 1 are reduced, indicating that the present invention can improve the binding force between ammonium polyphosphate and modified graphene oxide by depositing polydopamine on the surface of ammonium polyphosphate, thereby improving the mechanical properties and flame retardant properties of the material.

[0086] 2. Compared with Examples 1-3, the tensile strength and oxygen index of the products obtained in Comparative Examples 2 and 3 are reduced. It can be seen that excessive modified graphene oxide will occupy the binding sites of modified ammonium polyphosphate, reduce effective binding, and thus affect the performance of the material; compared with graphene oxide, the modified graphene oxide prepared by the present invention has better flame retardant effect.

[0087] 3. Compared with Examples 1-3, the tensile strength and oxygen index of the product obtained in Comparative Example 4 are both reduced. It can be seen that the performance of the modified graphene oxide prepared by the present invention is affected by the ratio of each reagent in its preparation process. By selecting a mass ratio within the range, the prepared material has excellent flame retardant properties.

[0088] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process method article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process method article or device.

[0089] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A process for preparing a flame retardant high-strength insulating material, characterized in that: The steps include: Step S1: ultrasonically dispersing the modified graphene oxide in anhydrous ethanol, adding the modified ammonium polyphosphate and mixing evenly, and obtaining a flame retardant after rotary evaporation, washing and drying; Step S2: uniformly mix polyvinyl chloride, cross-linked polyethylene, ethylene-vinyl acetate copolymer, flame retardant, talcum powder, calcium carbonate, compatibilizer and antioxidant to obtain a mixture; put the mixture into an extrusion device for mixing, extruding and granulating to obtain an insulating material.

2. The process for preparing a flame retardant high-strength insulating material according to claim 1, characterized in that: The insulating material comprises the following components by weight: 50-60 parts of polyvinyl chloride, 20-40 parts of cross-linked polyethylene, 10-15 parts of ethylene-vinyl acetate copolymer, 20-40 parts of flame retardant, 5-15 parts of talc, 10-20 parts of calcium carbonate, 6-12 parts of compatibilizer and 3-8 parts of antioxidant.

3. The process for preparing a flame retardant high-strength insulating material according to claim 2, characterized in that: The flame retardant comprises the following components by weight: 5-10 parts of modified graphene oxide and 15-30 parts of modified ammonium polyphosphate.

4. The process for preparing a flame retardant high-strength insulating material according to claim 3, characterized in that: The preparation method of the modified graphene oxide is as follows: Step (1): 2-chloro-4,6-diamino-1,3,5-triazine and anhydrous ethanol are uniformly mixed, 2,3-dimercaptosuccinic acid and KOH methanol solution are dripped into the mixture over a period of 20-40 minutes, the mixture is reacted at 70-80° C. for 24-28 hours, and after filtering, washing and drying, a thiol-containing compound is obtained; Under nitrogen protection, vanillin, thiol-containing compounds and anhydrous ethanol are mixed evenly, reacted at 65-75°C for 8-10 hours, and then DOPO is added, and the reaction is continued for 10-12 hours. After rotary evaporation, washing and drying, modified DOPO is obtained; Step (2): mixing a graphene oxide aqueous solution, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide, and ultrasonically dispersing for 30-60 minutes, adding a mixed solution of oleylamine, ethanol and deionized water, and continuing ultrasonically dispersing for 2-3 hours, stirring for 22-24 hours, and obtaining graphene oxide containing double bonds after centrifugation, filtration and drying; Step (3): The double-bond-containing graphene oxide, modified DOPO and a photoinitiator are uniformly mixed, and after ultraviolet irradiation, modified graphene oxide is obtained.

5. The process for preparing a flame retardant high-strength insulating material according to claim 4, characterized in that: In the step (3), the mass ratio of double-bond graphene oxide, modified DOPO and photoinitiator is 1:(2-4):(0.3-0.5).

6. The process for preparing a flame retardant high-strength insulating material according to claim 3, characterized in that: The preparation method of the modified ammonium polyphosphate is as follows: The ammonium polyphosphate, dopamine hydrochloride and deionized water are mixed evenly, Tris-HCl is added, the pH value of the system is adjusted to 8.5 with ammonia water, and the mixture is stirred for 24-36 hours. After centrifugation, washing and drying, the modified ammonium polyphosphate is obtained.

7. The process for preparing a flame retardant high-strength insulating material according to claim 6, characterized in that: The mass ratio of the ammonium polyphosphate, dopamine hydrochloride, Tris-HCl and deionized water is 1:(0.1-0.2):(0.05-0.10):(15-20).

8. The process for preparing a flame retardant high-strength insulating material according to claim 2, characterized in that: The compatibilizer is at least one of hydrogenated styrene-butadiene-styrene copolymer grafted with glycidyl methacrylate, ethylene-methyl acrylate grafted with glycidyl methacrylate, and styrene-acrylonitrile copolymer grafted with glycidyl methacrylate.

9. The process for preparing a flame retardant high-strength insulating material according to claim 2, characterized in that: The antioxidant is antioxidant 1010.

10. A flame retardant high-strength insulating material obtained according to the preparation process according to any one of claims 1 to 9.