A self-healing aramid paper and method of making the same

Abstract

The present application relates to the technical field of materials, in particular to a kind of self-healing aramid laminated paper and preparation method thereof.The present application is based on the demand of improving the self-healing ability of insulating material, and epoxy resin / nanocellulose microcapsules are prepared by using microcapsule technology, and are uniformly sprayed on the upper and lower surfaces of aramid insulating paper to obtain aramid laminated insulating paper.When microcracks or small damages appear in the material, the microcapsules at the corresponding position will break, release epoxy resin / nanocellulose, fill the damage area, and cure under certain conditions to restore the insulation performance and mechanical strength of the material.This self-healing mechanism greatly improves the reliability and safety of the insulating material, prolongs the service life of the material, and the prepared epoxy resin / nanocellulose microcapsules self-healing aramid laminated paper not only meets the demand of high-performance insulating material in power and electronic industry, but also provides a new solution to improve the reliability and safety of equipment.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of materials, in particular to a self-healing aramid paper and a preparation method thereof. BACKGROUND

[0002] In power systems, electronic devices and various high-performance electric machines, insulation materials play a crucial role. These application scenarios have very high requirements for insulation materials, not only excellent electrical insulation performance, mechanical strength and heat resistance, but also long-term stability and reliability. Traditional insulation materials, although excellent in some aspects, are difficult to meet all requirements, especially prone to minor damage during long-term use. These damages will gradually accumulate, eventually leading to a decline in mechanical properties and insulation performance, and even failure. Therefore, developing an insulation material with self-healing function has become the key to improving the reliability and extending the service life of electrical equipment. SUMMARY

[0003] Therefore, the technical problem to be solved by the present application is to provide a self-healing aramid paper and a preparation method thereof. The self-healing aramid paper provided by the present application can self-heal and repair after damage, restore mechanical strength and insulation performance, significantly improve the reliability and safety of dielectric materials, reduce performance degradation caused by material aging or minor damage, help extend the service life of electrical equipment, and reduce the need for maintenance and replacement.

[0004] The present application provides a self-healing aramid paper, comprising: an aramid insulation paper core layer and an epoxy resin composite nanocellulose microcapsule repair layer arranged on the surface of the aramid insulation paper core layer; the epoxy resin composite nanocellulose microcapsule repair layer is prepared from raw materials including nanocellulose composite, epoxy resin and temperature-sensitive polymer.

[0005] In the self-healing aramid paper provided by the present application, the epoxy resin composite nanocellulose microcapsule repair layer is arranged on the surface of the aramid insulation paper core layer. Specifically, the epoxy resin composite nanocellulose microcapsule repair layer is arranged on the upper surface and the lower surface of the aramid insulation paper core layer. The thickness of the epoxy resin composite nanocellulose microcapsule repair layer is 10-15 μm. The self-healing aramid paper provided by the present application is provided with an epoxy resin composite nanocellulose microcapsule repair layer. When the material has microcracks or minor damage, the microcapsules at the corresponding position will break, releasing epoxy resin / nanocellulose, filling the damaged area, and curing under certain conditions to restore the insulation performance and mechanical strength of the material.

[0006] The self-healing aramid paper provided by the present application comprises an aramid insulation paper core layer, an epoxy resin composite nanocellulose microcapsule repair layer, and an aramid paper surface layer. The epoxy resin composite nanocellulose microcapsule repair layer is prepared from raw materials comprising a nanocellulose composite, an epoxy resin, and a temperature-sensitive polymer. Specifically, the nanocellulose composite is prepared from raw materials comprising nanocellulose and polyurethane at a mass ratio of 1: (0.6-0.8); the nanocellulose is selected from at least one of carbon nanocellulose, cellulose nanocrystals (CNC), or bacterial cellulose (BC); the temperature-sensitive polymer is selected from at least one of poly (N-isopropyl acrylamide), poly (N-ethyl acrylamide), poly (N,N-diethyl acrylamide), or poly (N,N-dimethyl acrylamide); the modified epoxy resin is prepared from raw materials comprising unmodified epoxy resin, toughness modifier, tertiary amine compound, curing agent, and accelerator; the mass ratio of the unmodified epoxy resin, the toughness modifier, and the tertiary amine compound is (15-20):(3-5.5):(0.8-1.6); and the mass ratio of the total mass of the unmodified epoxy resin, the toughness modifier, and the tertiary amine compound to the curing agent and the accelerator is (85-100):(70-80):(1.2-1.8). In some embodiments of the present application, the toughness modifier is selected from at least one of carboxyl-terminated polyester elastomer, polyurethane elastomer, carboxyl-terminated polyurethane, or acrylate elastomer; the tertiary amine compound is selected from at least one of triethylamine, trimethylamine, or N,N-dimethyl aniline; the curing agent is selected from at least one of methyl hexahydrophthalic anhydride, adipic acid dianhydride, methyl tetrahydrophthalic anhydride, or vinyl triethoxysilane; and the accelerator is selected from at least one of 2,4,6-tris (dimethylaminomethyl) phenol (Q-DMP 30), N,N-dimethyl aminomethyl phenol (DMP-10), N,N-dimethyl benzylamine (BDMA), or triethylene tetramine (TETA).

[0007] The aramid paper provided by the present application comprises an aramid insulation paper core layer, an epoxy resin composite nanocellulose microcapsule repair layer, and an aramid paper surface layer. The aramid insulation paper core layer is prepared from aramid fibers and boron nitride nanotubes. The filling concentration of the boron nitride nanotubes in the aramid insulation paper core layer is 5 wt% to 15 wt%. In some embodiments of the present application, the thickness of the aramid insulation paper core layer is 25 μm to 35 μm, preferably 30 μm. The aramid insulation paper core layer is prepared from a composite of aramid fibers and boron nitride nanotubes, and has excellent insulation performance, mechanical performance, and temperature resistance, to a certain extent, resisting the negative effects caused by minor damage to the surface material.

[0008] The present application also provides a preparation method of the self-healing aramid paper. The preparation method comprises the following steps: coating an epoxy resin composite nanocellulose microcapsule dispersion liquid on the surface of the aramid insulation paper core layer, and hot pressing to obtain the self-healing aramid paper.

[0009] The aramid insulation paper core layer is prepared from aramid fibers and boron nitride nanotubes. Specifically, the aramid fibers are sheared, and the obtained material is subjected to ultrasonic treatment for 2.5 h to 3.5 h. Then, the obtained material is mixed with boron nitride nanotubes and subjected to ultrasonic treatment for 1.5 h to 2.5 h. Then, beating and papermaking are performed to obtain the aramid insulation paper core layer. The shearing and ultrasonic treatment of the aramid fibers can improve the dispersibility and uniformity of the fibers. The beating time is 35 min to 45 min, and the beating speed is 2500 rpm to 3500 rpm. After beating, the present application further includes screening to remove large particles and removing air bubbles. Before shearing the aramid fibers, the present application further includes pretreating the aramid fibers, specifically, cleaning the aramid fibers with an organic solvent, water, and an alkaline solution to remove impurities and grease on the surface and improve the hydrophilicity of the fibers.

[0010] The epoxy resin composite nanocellulose microcapsule dispersion liquid is prepared from epoxy resin composite nanocellulose microcapsules and an epoxy resin-based adhesive. Specifically, the epoxy resin composite nanocellulose microcapsules and the epoxy resin-based adhesive are mixed and stirred for 1 h to 2 h. Then, vacuum degassing is performed to eliminate air bubbles introduced during the mixing process to obtain the epoxy resin composite nanocellulose microcapsule dispersion liquid. The epoxy resin-based adhesive is selected from at least one of bisphenol A epoxy resin, bisphenol F epoxy resin, or epoxy phenolic resin. The mass fraction of the epoxy resin composite nanocellulose microcapsules in the dispersion liquid is 5 wt% to 20 wt%.

[0011] In the dispersion liquid, the epoxy resin composite nanocellulose microcapsules are prepared from a nanocellulose composite solution, an epoxy resin emulsion, and a temperature-sensitive polymer solution. Specifically, the nanocellulose composite solution and the epoxy resin emulsion are mixed to obtain a microcapsule suspension with a preliminary shell. Then, the temperature-sensitive polymer solution is added to the microcapsule suspension to obtain an epoxy resin composite nanocellulose microcapsule precursor solution. The precursor solution is subjected to solidification, washing, and drying to obtain the epoxy resin composite nanocellulose microcapsules. More specifically, the solidification includes adjusting the pH of the precursor solution to 2 to 3, heating at 55°C to 65°C for 1.5 h to 2.5 h, heating at a temperature of 115°C to 125°C for 3.5 h to 4.5 h to obtain the epoxy resin composite nanocellulose microcapsules.

[0012] In the process of preparing the epoxy resin composite nanocellulose microcapsule, the temperature-sensitive polymer in the temperature-sensitive polymer solution is the same as the above, and will not be repeated; the nanocellulose composite solution is prepared from a nanocellulose solution and a polyurethane solution, and the concentration of the nanocellulose solution is 15 wt%-25 wt%. Specifically, the nanocellulose composite solution is prepared by the following method: dispersing nanocellulose in water, heating and stirring at 55-65°C for 35-45 min to obtain a nanocellulose solution; mixing the polyurethane solution and the nanocellulose solution, heating and stirring at 55-65°C for 25-35 min to obtain a nanocellulose composite solution. The nanocellulose and polyurethane of the present application are the same as the above, and will not be repeated.

[0013] In the process of preparing the epoxy resin composite nanocellulose microcapsule, the epoxy resin emulsion is a modified epoxy resin emulsion, which is obtained by mixing unmodified epoxy resin, toughness modifier, tertiary amine compound, curing agent, accelerator and surfactant solution. Specifically, the modified epoxy resin emulsion of the present application is prepared by the following method: adding a toughness modifier solution and a tertiary amine compound to an unmodified epoxy resin solution, then stirring the resulting material liquid at 65-75°C for 55-65 min, then adding a curing agent and an accelerator to it, stirring for 0.5-1.5 h, then mixing the resulting material with a surfactant solution, heating at 75-85°C for 6-10 h to obtain the modified epoxy resin emulsion. The surfactant in the surfactant solution of the present application is selected from at least one of cetyltrimethylammonium bromide, sodium dodecyl sulfate or polyethylene glycol octylphenyl ether, and the concentration of the surfactant in the surfactant solution is 1.5 wt%-4 wt%. The total volume of the material obtained by mixing the unmodified epoxy resin, toughness modifier, tertiary amine compound, curing agent and accelerator of the present application accounts for 15%-30% of the total volume of the modified epoxy resin emulsion. The toughness modifier, tertiary amine compound, curing agent and accelerator of the present application are the same as the above, and will not be repeated.

[0014] The present application coats the surface of the aramid insulation paper core layer with an epoxy resin composite nanocellulose microcapsule dispersion, hot-presses, and obtains a self-healing aramid laminated paper. Specifically, the present application lays the aramid insulation paper core layer, coats the upper and lower surfaces of the aramid insulation paper core layer with an epoxy resin composite nanocellulose microcapsule dispersion, and then hot-presses the obtained material, and vacuum dries to obtain a self-healing aramid laminated paper. The hot-pressing temperature of the present application is 100℃-140℃; the hot-pressing time is 15 min-25 min; and the hot-pressing pressure is 130 MPa-170 MPa. The coating time of the present application is 4 h-8 h. The aramid insulation paper core layer and the epoxy resin composite nanocellulose microcapsules in the dispersion of the present application are the same as described above, and will not be described again. The final self-healing aramid laminated paper obtained by the present application is also the same as described above, and will not be described again.

[0015] The present application provides a self-healing aramid laminated paper and a preparation method thereof. Based on the demand for improving the self-healing ability of insulation materials, the present application uses microcapsule technology to prepare epoxy resin / nanocellulose microcapsules, and uniformly sprays the epoxy resin / nanocellulose microcapsules on the upper and lower surfaces of aramid insulation paper to obtain aramid laminated insulation paper. When the material has microcracks or small damages, the microcapsules at the corresponding position will break, release epoxy resin / nanocellulose, fill the damaged area, and cure under certain conditions to restore the insulation performance and mechanical strength of the material. This self-healing mechanism greatly improves the reliability and safety of the insulation material, prolongs the service life of the material, and the prepared epoxy resin / nanocellulose microcapsule self-healing aramid laminated paper not only meets the demand for high-performance insulation materials in the power and electronics industries, but also provides a new solution for improving the reliability and safety of equipment. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 A scanning electron microscope image of the epoxy resin / nanocellulose microcapsules obtained in Example 1 of the present application;

[0017] Figure 2 A scanning electron microscope image of aramid fibers before pretreatment used in the specific embodiment of the present application. DETAILED DESCRIPTION

[0018] The present application discloses a self-healing aramid laminated paper and a preparation method thereof. Those skilled in the art can refer to the content herein and appropriately improve the process parameters. It is particularly important to note that all similar substitutions and changes are obvious to those skilled in the art, and they are considered to be included in the present application. The method and application of the present application have been described by the preferred embodiments, and relevant personnel can obviously modify or appropriately change and combine the method and application herein without departing from the content, spirit and scope of the present application, to realize and apply the present application technology.

[0019] The present application is further described below in conjunction with examples:

[0020] Example 1

[0021] The preparation of the self-healing aramid laminated paper using epoxy resin / nanocellulose microcapsules according to the present application comprises the following steps S1, S2 and S3:

[0022] S1, Preparation of epoxy resin / nanocellulose microcapsules, comprising the following steps:

[0023] S11, Epoxy resin pretreatment

[0024] First, the epoxy resin was weighed and placed in a 45°C constant temperature water bath for heating for 15 min, then acetone was added, and a magnetic stirrer was used for stirring for 30 min to obtain epoxy resin 1. Second, carboxyl-terminated polyester elastomer (toughness modifier) was weighed and mixed with acetone, and a 35°C constant temperature magnetic stirrer was used for stirring for 30 min to obtain a modifier mixture. Then, the carboxyl-terminated polyester elastomer mixture was slowly added to the epoxy mixture 1, and a 55°C constant temperature magnetic stirrer was used for high-speed stirring. After stirring for 30 min, triethylamine (a tertiary amine compound) was added and stirring was continued for 1 h to obtain epoxy resin 2. Finally, the epoxy resin 2 was placed in a 70°C constant temperature oil bath and stirred for 60 min. After completely removing the acetone, vacuum degassing was performed to obtain bubble-free epoxy resin 3. The mass ratio of epoxy resin, carboxyl-terminated polyester elastomer and tertiary amine compound is 15:3:0.8.

[0025] S12, Mixing of epoxy resin and curing agent

[0026] The above epoxy resin 3, methylhexahydrophthalic anhydride (curing agent) and Q-DMP 30 (accelerator) were weighed and mixed, and stirred at room temperature for 1 h to obtain epoxy resin 4. The mass ratio of epoxy resin 3, curing agent and accelerator is 85:70:1.2.

[0027] S13, Preparation of nanocellulose aqueous solution

[0028] Nanocellulose CNF was weighed and dispersed in deionized water, and heated and stirred in a 60°C constant temperature water bath for 40 min to prepare a solution with a concentration of 15 wt%, labeled as CNF aqueous solution.

[0029] S14, Preparation of nanocomposite solution

[0030] The above CNF aqueous solution was added to the polyurethane solution, and heated and stirred in a 60°C constant temperature water bath for 30 min to form a uniform nanocomposite solution. The mass ratio of CNF and polyurethane is 1:0.6.

[0031] S15, Emulsification of microcapsule core material

[0032] Hexadecyl trimethyl ammonium bromide (surfactant) was weighed and dispersed in deionized water, and stirred at 80°C for 15 min to obtain a surfactant aqueous solution; the above-mentioned epoxy resin 4 was slowly added dropwise into the hexadecyl trimethyl ammonium bromide solution, and stirred using a magnetic stirrer during the dropwise addition, and then ultrasonic treatment was performed for 30 min, and the temperature was increased to 80°C, and the reaction was performed for 6 h to form a stable epoxy resin emulsion, which was marked as epoxy resin 5. The epoxy resin 4 accounted for 15% of the total volume.

[0033] S16, Formation of microcapsule shell

[0034] The above-mentioned nanocomposite solution was slowly added into the epoxy resin 5, and stirred at 60°C for 2 h to obtain a microcapsule suspension with a preliminary shell formed, which was marked as microcapsule suspension 1; a poly(N-isopropyl acrylamide) solution (temperature-sensitive polymer solution) was slowly added into the microcapsule suspension 1 to prepare an epoxy resin / nano-cellulose microcapsule.

[0035] S17, Microcapsule curing process

[0036] The pH value of the epoxy resin / nano-cellulose microcapsule suspension was adjusted to 2.3 by hydrochloric acid (acidic regulator), and the suspension was kept at 60°C for 2 h to promote uniform curing, and then the temperature was increased to 120°C and kept for 4 h to complete the curing process.

[0037] S18, Microcapsule post-treatment

[0038] The cured epoxy resin microcapsule was repeatedly washed with deionized water, and after washing, centrifugal separation was performed, and after removing impurities and excess surfactant in the solution, freeze-drying was performed for 36 h to prepare an epoxy resin / nano-cellulose microcapsule for standby use. As shown in Figure 1 , Figure 1 is a scanning electron microscope image of the epoxy resin / nano-cellulose microcapsule obtained in Example 1 of the present application.

[0039] S2, Preparation of aramid insulation paper

[0040] S21, Pretreatment of aramid fiber

[0041] The aramid fiber was cut into small pieces of about 0.5 cm long, and after ultrasonic treatment in acetone for 36 h, the fiber was repeatedly washed with deionized water, and then added into an alkaline environment, stirred for 2 h, repeatedly washed with deionized water again, and vacuum dried at 45°C for 24 h to remove surface impurities and grease and improve the hydrophilicity of the fiber. As shown in Figure 2 , Figure 2 is a scanning electron microscope image of the aramid fiber before pretreatment used in the specific embodiment of the present application.

[0042] S22, Preparation of aramid pulp

[0043] The treated aramid fibers were weighed and subjected to high-speed shearing to be broken into fine microfibers, and then dispersed in deionized water for ultrasonic treatment for 3 h to improve the dispersion and uniformity of the fibers. The aramid fibers after ultrasonic treatment were compounded with boron nitride nanotubes (BNNT), and then subjected to ultrasonic treatment for 2 h. The aramid fibers were put into a beater, and after beating, large particles were removed by screening, and then ultrasonic treatment was performed to remove air bubbles to obtain air bubble-free uniform aramid pulp, which was marked as AF / BNNT. The filling concentration of BNNT was 5 wt%, the beating time was 40 min, and the beating speed was 3000 rpm.

[0044] S23, Preparation of aramid insulation paper

[0045] The air bubble-free uniform aramid pulp was sent into a paper machine to prepare AF / BNNT aramid insulation paper, and the thickness of the insulation paper was 30 μm.

[0046] S3, Preparation of self-healing aramid laminated paper using epoxy resin / nano-cellulose microcapsules

[0047] S31, Preparation of epoxy resin / nano-cellulose microcapsule dispersion

[0048] The epoxy resin / nano-cellulose microcapsules were slowly added to the epoxy resin-based adhesive on a constant-temperature magnetic stirrer at 45°C, and stirring was continued for 1 h. After stirring, vacuum degassing was performed to remove air bubbles introduced during mixing. The amount of epoxy resin / nano-cellulose microcapsules added was 10% of the total weight.

[0049] S32, Preparation of aramid laminated paper rough paper

[0050] The AF / BNNT aramid insulation paper was laid flat, and the epoxy resin / nano-cellulose microcapsule dispersion was uniformly sprayed onto the upper and lower surfaces of the aramid insulation paper using a spraying machine to obtain aramid laminated insulation paper rough paper. Subsequently, aramid laminated paper was prepared by high-temperature hot pressing and vacuum drying at 45°C for 48 h. The spraying time was 4 h, the spraying thickness was 10 μm, the hot pressing temperature was 120°C, the hot pressing time was 20 min, and the pressure was 150 MPa.

[0051] Example 2

[0052] Compared with Example 1, the difference lies in that the mass ratio of epoxy resin, carboxyl-terminated polyester elastomer and tertiary amine compound in step S11 is 15:5.5:1.6.

[0053] Example 3

[0054] Compared with Example 1, the difference is that the mass ratio of epoxy resin 3, curing agent and accelerator in step S12 is: 85:80:1.8.

[0055] Example 4

[0056] Compared with Example 1, the difference is that the concentration of CNF aqueous solution in step S13 is 20 wt%.

[0057] Example 5

[0058] Compared with Example 1, the difference is that the concentration of CNF aqueous solution in step S13 is 25 wt%.

[0059] Example 6

[0060] Compared with Example 1, the difference is that the mass ratio of CNF and polyurethane in step S14 is 1:0.8.

[0061] Example 7

[0062] Compared with Example 1, the difference is that the volume fraction of epoxy resin 4 in step S15 is 20%.

[0063] Example 8

[0064] Compared with Example 1, the difference is that the volume fraction of epoxy resin 4 in step S15 is 30%.

[0065] Example 9

[0066] Compared with Example 1, the difference is that the filling concentration of BNNT in step S22 is 10 wt%.

[0067] Example 10

[0068] Compared with Example 1, the difference is that the filling concentration of BNNT in step S22 is 15 wt%.

[0069] Example 11

[0070] Compared with Example 1, the difference is that the addition amount of epoxy resin / nanocellulose microcapsules in step S31 accounts for 20% of the total weight.

[0071] Example 12

[0072] Compared with Example 1, the difference is that the spraying time in step S32 is 8 h and the spraying thickness is 15 μm.

[0073] Comparative Example 1

[0074] Compared with Example 1, the difference is that the aramid fiber in step S21 is directly sent into the paper machine after beating treatment, without compounding BNNT, and without spraying epoxy resin / nanocellulose microcapsule dispersion on the upper and lower surfaces, and aramid insulation paper is prepared after high-temperature hot pressing.

[0075] Comparative Example 2

[0076] Compared with Example 1, the difference is that the aramid paper pulp in step S22 is directly sent into the paper machine, without spraying epoxy resin / nanocellulose microcapsule dispersion on the upper and lower surfaces, and AF / BNNT aramid insulation paper is prepared after high-temperature hot pressing. The proportions of the substances are the same, and the BNNT filling concentration is 5 wt%.

[0077] Comparative Example 3

[0078] Compared with Example 1, the difference is that the core layer aramid insulation paper is not compounded with BNNT. The proportions of the substances are the same.

[0079] Comparative Example 4

[0080] The other preparation steps of the present comparative example are the same as those of Example 1, except that the epoxy resin / nanocellulose microcapsule is not used, and in the preparation of the aramid laminated paper base paper in step S32, the sprayed material on the upper layer of the aramid laminated paper is epoxy resin 5, and the sprayed material on the lower layer of the aramid laminated paper is nanocomposite solution. The spraying thickness and the proportions of the substances are the same.

[0081] In order to evaluate the performance and self-healing ability of a self-healing aramid laminated paper using epoxy resin / nanocellulose microcapsule, the present application uses a precisely controlled method to make fine cuts or cavities on the insulation paper, simulates actual damage, sets the environmental temperature after damage to 120℃, so as to promote the self-healing of the epoxy resin / nanocellulose microcapsule, and tests the performance before damage, after damage and after self-healing (self-healing for 24 hours at an environmental temperature of 45℃). The mechanical property test results are shown in Table 1, and the breakdown characteristic test results are shown in Table 2.

[0082] Table 1

[0083]

[0084] Table 2

[0085]

[0086] As can be seen from Tables 1 and 2, the aramid laminated paper self-healing aramid laminated paper prepared by using the epoxy resin / nanocellulose microcapsule and the preparation method thereof can effectively restore the mechanical strength and insulation performance of the insulation paper after a slight damage, significantly improves the reliability and safety of the dielectric material, reduces the performance attenuation caused by material aging or slight damage, helps to prolong the service life of the electrical equipment, and reduces the demand for maintenance and replacement.

[0087] The above merely provides the preferred embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can make equivalent replacements or changes to the technical solutions and the inventive concept of the present application within the technical scope disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A self-healing aramid paper laminate, characterized in that, Comprise: an aramid insulation paper core layer and an epoxy resin composite nanocellulose microcapsule repair layer disposed on the surface of the aramid insulation paper core layer; the aramid insulation paper core layer is made of aramid fiber and boron nitride nanotube; the epoxy resin composite nanocellulose microcapsule repair layer is formed by coating an epoxy resin composite nanocellulose microcapsule dispersion liquid; the epoxy resin composite nanocellulose microcapsule dispersion liquid is made of epoxy resin composite nanocellulose microcapsules and an epoxy resin-based adhesive; the epoxy resin composite nanocellulose microcapsules are prepared by the following method: mixing a nanocellulose composite solution, an epoxy resin emulsion and a temperature-sensitive polymer solution and adjusting the pH to 2-3, then heating at 55-65℃ for 1.5-2.5h, and then heating at 115-125℃ for 3.5-4.5h to obtain the epoxy resin composite nanocellulose microcapsules; the nanocellulose composite solution is prepared by the following method: dispersing nanocellulose in water, heating and stirring at 55-65℃ for 35-45min to obtain a nanocellulose solution; mixing a polyurethane solution and the nanocellulose solution, and heating and stirring at 55-65℃ for 25-35min to obtain the nanocellulose composite solution; the epoxy resin is a modified epoxy resin prepared from raw materials including an unmodified epoxy resin, a toughness modifier, a tertiary amine compound, a curing agent and an accelerator; the temperature-sensitive polymer is at least one selected from poly(N-isopropyl acrylamide), poly(N-ethyl acrylamide), poly(N,N-diethyl acrylamide) or poly(N,N-dimethyl acrylamide).

2. The self-healing aramid paper of claim 1, wherein, the mass ratio of the nanocellulose and the polyurethane is 1:(0.6-0.8); the mass ratio of the unmodified epoxy resin, the toughness modifier and the tertiary amine compound is (15-20):(3-5.5):(0.8-1.6); the mass ratio of the total mass of the unmodified epoxy resin, the toughness modifier and the tertiary amine compound to the mass of the curing agent and the accelerator is (85-100):(70-80):(1.2-1.8).

3. The self-healing aramid laminated paper according to claim 1, wherein the toughness modifier is at least one selected from a carboxyl-terminated polyester elastomer, a polyurethane elastomer or an acrylate elastomer; the tertiary amine compound is at least one selected from triethylamine, trimethylamine and N,N-dimethyl aniline; the curing agent is at least one selected from methyl hexahydrophthalic anhydride, adipic acid dianhydride, methyl tetrahydrophthalic anhydride and vinyl triethoxysilane; the accelerator is at least one selected from 2,4,6-tris(dimethylaminomethyl)phenol, N,N-dimethyl aminomethyl phenol, N,N-dimethyl benzylamine and triethylene tetramine.

4. The self-healing aramid paper of claim 1, wherein, the filling concentration of the boron nitride nanotube in the aramid insulation paper core layer is 5-15 wt%.

5. The self-healing aramid paper of claim 1, wherein, the thickness of the epoxy resin composite nanocellulose microcapsule repair layer is 10-15μm.

6. The method of making a self-healing aramid paper laminate of any one of claims 1-5, wherein, comprise the following steps: Coating an epoxy resin composite nanocellulose microcapsule dispersion liquid on the surface of the aramid insulation paper core layer, hot pressing to obtain a self-healing aramid laminated paper.

7. The production method according to claim 6, characterized by, The mass ratio of the epoxy resin composite nanocellulose microcapsule in the dispersion liquid is 5 wt%-20 wt%.

8. The preparation method according to claim 6, characterized in that, The temperature of the hot pressing is 100 DEG C-140 DEG C; The pressure of the hot pressing is 130 MPa-170 MPa; The time of the hot pressing is 15 min-25 min.

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