Bionic epoxy adhesive for mica composite material and preparation method thereof

Abstract

The invention relates to the technical field of preparation of master composite materials, in particular to a bionic epoxy adhesive for a mica composite material and a preparation method of the bionic epoxy adhesive. The bionic epoxy adhesive for the mica composite material is prepared from the following raw materials in parts by weight: 100 parts of bisphenol A epoxy resin, 50-75 parts of a curing agent, 10-20 parts of an epoxy active diluent, 3-6 parts of an accelerant and 8-20 parts of hard-core soft-shell particles, the hard-core soft-shell particle takes palygorskite nanoparticles as a hard core and PU as a soft shell, and dopamine or tannic acid is grafted outside the soft shell of the hard-core soft-shell particle. The hard-core soft-shell particles are used for toughening and reinforcing epoxy resin curing, so that the epoxy resin is endowed with good impact toughness and good mechanical strength and Young modulus, and the use requirements of epoxy mica piece products are better met.

Description

Technical Field

[0001] The invention relates to the technical field of preparing mother composite materials, in particular to a bionic epoxy adhesive for mica composite materials and a preparation method thereof. Background Art

[0002] Mica has excellent high temperature resistance, flame retardancy, and electrical insulation properties. It also has good processability and stability. Coupled with its processing maturity and cost advantages, it has been widely used in new energy vehicles, rail transit, aerospace ships, wires and cables, smart home appliances and other related industrial fields.

[0003] Epoxy mica products are epoxy mica electrical insulation products made of epoxy resin as adhesive, composited with mica flakes or mica powder paper and various fiber papers, cloth and other reinforcing materials. They are epoxy mica composite materials with three-dimensional structure formed by bonding and high-temperature pressing.

[0004] Currently, the predominant curing agent for epoxy resins in epoxy mica products is anhydride. The advantages of anhydride curing agents include: 1. low volatility, low toxicity, and low irritation; 2. low shrinkage and good dimensional stability of the cured product; 3. high heat resistance and high mechanical strength of the cured product, ensuring the mechanical properties of the epoxy mica product; and 4. excellent electrical properties, ensuring the electrical insulation of the epoxy mica product. However, epoxy mica products made with anhydride curing agents also suffer from relatively long cure times, high brittleness, and poor resistance to crack initiation and propagation, which affects the production of epoxy mica products and limits their application.

[0005] In order to improve the impact toughness of epoxy mica products, a second phase is added to the epoxy resin for toughening. Existing second-phase toughening methods such as rubber elastomers and thermoplastic resins are used to toughen EP, but the viscosity increases after toughening, which limits the molding process. The core-shell structured second-phase toughening particles have a rubber elastomer or thermoplastic resin as the core and an acrylic polymer as the shell. The epoxy resin prepared with the core-shell structured second-phase toughening particles has an increasing amount of second-phase toughening particles. The impact toughness of the epoxy resin gradually increases, but the flexural strength and elastic modulus of the epoxy resin decrease significantly with the increase in the amount of second-phase toughening particles added.

[0006] In summary, although the existing epoxy mica products toughened with core-shell second-phase toughening particles have improved the impact toughness and yield rate of anisotropic mica products, their overall mechanical strength and Young's modulus inevitably decrease, limiting the application of epoxy mica products in the high-end market. Summary of the Invention

[0007] In order to solve the problem in the above-mentioned technology that the mechanical strength, Young's modulus and impact toughness of epoxy resin cannot be taken into account at the same time, which limits the application of epoxy mica products in the high-end market, the present invention provides a bionic epoxy adhesive for mica composite materials and a preparation method thereof.

[0008] The present invention provides a biomimetic epoxy adhesive for mica composite materials, which is achieved through the following technical solutions: A bionic epoxy adhesive for mica composite materials is prepared from the following raw materials in parts by weight: 100 parts of bisphenol A epoxy resin, 50-75 parts of a curing agent, 10-20 parts of an epoxy reactive diluent, 3-6 parts of an accelerator, and 8-20 parts of hard-core soft-shell particles; the hard-core soft-shell particles have palygorskite nanoparticles as a hard core and polyurethane as a soft shell, and dopamine or tannic acid is grafted onto the soft shell of the hard-core soft-shell particles.

[0009] The present invention employs hard-core soft-shell particles to toughen and reinforce epoxy resin curing, imparting excellent impact toughness while also possessing good mechanical strength and Young's modulus, better meeting the requirements for epoxy mica products. Furthermore, the dopamine or tannic acid grafted onto the outer surface of the hard-core soft-shell particles, i.e., the presence of phenolic hydroxyl groups on the outer surface of the hard-core soft-shell particles, promotes the curing reaction, shortens the curing cycle, and thereby improves the yield of epoxy mica products.

[0010] Preferably, the preparation method of the hard-core soft-shell microparticles is as follows: Step 1: calcining and activating the palygorskite nanoparticles, and performing surface amination modification on the activated palygorskite nanoparticles to obtain amino-modified palygorskite nanoparticles; Step 2: uniformly dispersing the amino-modified palygorskite nanoparticles, a surfactant, and deionized water at high speed, and then ultrasonically stirring for 3-6 minutes to obtain an amino-modified palygorskite nanoparticle dispersion; Step 3: maintaining ultrasonic stirring and heating to 50-85° C., adding an aqueous polyurethane dispersion dropwise to the amino-modified palygorskite nanoparticle dispersion, wherein the mass ratio of the amino-modified palygorskite nanoparticles to the polyurethane latex particles in the aqueous polyurethane dispersion is 1:(0.1-2), and continuing the reaction for 15-30 minutes after the addition is completed; Step 4: maintaining ultrasonic stirring and a temperature of 50-85°C, adding a dopamine aqueous solution or a tannic acid aqueous solution to the mixed solution in step 3, wherein the mass ratio of amino-modified palygorskite nanoparticles to dopamine or tannic acid is 1:(0.01-0.05), continuing the reaction for 2-4 hours after the addition is completed, and drying to obtain hard-core soft-shell particles.

[0011] The preparation method of the present invention uses water as the dispersion medium, has relatively low reagent costs, less pollution, a relatively environmentally friendly production process, and relatively simple preparation operations, which facilitates mass production.

[0012] Further preferably, in the step 1, the palygorskite nanoparticles are placed in a muffle furnace and heated to 140-160 ° C for calcination activation treatment for 1-2h, 5-10 parts by mass of the obtained activated palygorskite nanoparticles are placed in 200-400 parts by mass of an aminosilane aqueous solution with a concentration of 0.5-5wt%, wherein the aminosilane in the aminosilane aqueous solution is γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropylmethyldiethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, N-β-(aminoethyl)-y-aminopropylmethyldimethoxysilane. At least one of the following is added, the water bath is heated to 60-70 ° C and ultrasonically stirred and dispersed for 30-60min, filtered, washed multiple times, and dried to obtain amino-modified palygorskite nanoparticles.

[0013] By adopting the above technical solution, the dispersibility of amino-modified palygorskite nanoparticles in water can be improved, thereby facilitating uniform chemical bond reaction on the outer surface of the amino-modified palygorskite nanoparticles to form soft-shell PU. The prepared hard-core soft-shell particles have a relatively better toughening effect on epoxy resin.

[0014] Preferably, the surfactant in step 2 is at least one of sodium lauryl sulfate, sodium didodecylphenyl ether disulfonate, octylphenol polyoxyethylene ether OP-10, sodium hexadecyl sulfate, sodium dodecyl polyoxyethylene ether sulfate, sodium dodecylbenzenesulfonate, sodium dodecylsulfonate, and sodium rosinate.

[0015] Preferably, the aqueous polyurethane dispersion includes aqueous polyurethane dispersion A and aqueous polyurethane dispersion B, the end-capping functional group of the polyurethane particle particles in the aqueous polyurethane dispersion A is -NCO, and the polymer main chain of the polyurethane particle particles contains an active double bond; the end of the polyurethane particle particles in the aqueous polyurethane dispersion B is capped with hydroxy acrylate or hydroxy methacrylate.

[0016] Preferably, in step three, the temperature is raised to 50-65° C. under ultrasonic stirring, and the aqueous polyurethane dispersion A is added dropwise to the amino-modified palygorskite nanoparticle dispersion. The mass ratio of the amino-modified palygorskite nanoparticles to the polyurethane latex particles in the aqueous polyurethane dispersion A is 1:(0.1-0.5). After the aqueous polyurethane dispersion A is added dropwise, the reaction is continued for 5-10 minutes, and the temperature is raised to 80-65° C. under ultrasonic stirring, and the amino-modified palygorskite nanoparticle dispersion is added dropwise. Aqueous polyurethane dispersion B and potassium persulfate emulsion are simultaneously added dropwise, wherein the potassium persulfate emulsion is prepared from 0.4-0.6 parts of potassium persulfate, 0.8-1.6 parts of octylphenol polyoxyethylene ether OP-10, 0.8-1.6 parts of sodium dodecylsulfonate and 100 parts of deionized water, and the mass ratio of amino-modified palygorskite nanoparticles to polyurethane latex particles in aqueous polyurethane dispersion B is 1:(0.8-1.6). After the dropwise addition is completed, the reaction is continued for 15-30 minutes.

[0017] By adopting the above technical solution, it is easy to adjust the thickness and hardness of the soft shell PU formed on the outer surface of the amino-modified palygorskite nanoparticles, that is, the Shore hardness and mechanical strength of the soft shell PU are better, and the prepared hard-core soft-shell particles have a relatively better toughening effect on epoxy resin, and the mechanical strength and Young's modulus retention rate are also better.

[0018] Preferably, the bisphenol A epoxy resin is composed of bisphenol A epoxy resin E44 and modified bisphenol A epoxy resin in a mass ratio of 100:(10-25); the modified bisphenol A epoxy resin is made of bisphenol A epoxy resin E20, 1,3,5-tris(3-isocyanatomethylphenyl)-1,3,5-triazine-2,4,6(1H,2H,5H)-trione, dibutyltin dilaurate, methyl ethyl ketone oxime, and a polar solvent.

[0019] Preferably, the preparation method of the modified bisphenol A epoxy resin is as follows: Step 1: dissolving epoxy resin E20 in acetone to form an epoxy resin E20 solution; Step 2: Add 1,3,5-tris(3-isocyanatomethylphenyl)-1,3,5-triazine-2,4,6(1H,2H,5H)-trione and dibutyltin dilaurate to the epoxy resin E20 solution, wherein the molar amount of -NCO in the 1,3,5-tris(3-isocyanatomethylphenyl)-1,3,5-triazine-2,4,6(1H,2H,5H)-trione is (3-3.03):1, and the mass ratio of the dibutyltin dilaurate to the epoxy resin E20 is 1:(800-2000), and the temperature is raised to 50-60° C. and the reaction is carried out for 1-2 hours; Step 2: maintaining the temperature at 50-60° C., adding methyl ethyl ketone oxime, wherein the molar ratio of the methyl ethyl ketone oxime to the molar ratio of the 1,3,5-tris(3-isocyanatomethylphenyl)-1,3,5-triazine-2,4,6(1H,2H,5H)-trione is (2-2.02):1, reacting at 50-60° C. for 2-4 hours until the -NCO content is 0, and removing acetone by reduced pressure distillation to obtain the finished modified bisphenol A epoxy resin.

[0020] The finished modified bisphenol A epoxy resin prepared in the present invention can improve the viscosity of the epoxy resin on the one hand, which is beneficial to the processing performance and construction performance of the finished epoxy resin. On the other hand, it has 1,3,5-tris(3-isocyanatomethylphenyl)-1,3,5-triazine-2,4,6(1H,2H,5H)-trione grafted on the side chain, that is, a multi-phenyl ring structure grafted on the side chain, which can improve the rigidity, heat resistance, flame retardancy, mechanical strength and Young's modulus of the epoxy resin cured product, and the blocked methyl ethyl ketone oxime will be unblocked above 120°C, improving the overall cross-linking density, further improving the rigidity, heat resistance, flame retardancy, mechanical strength and Young's modulus of the epoxy resin cured product. In addition, the modified bisphenol A epoxy resin contains tertiary amine groups, which can act as a accelerator, shorten the curing cycle, and thus improve the yield of epoxy mica products.

[0021] Preferably, the curing agent is at least one of methyltetrahydrophthalic anhydride, pyromellitic anhydride dianhydride, phthalic anhydride, trimellitic anhydride, benzophenone tetracarboxylic anhydride, and maleic anhydride; Preferably, the accelerator is at least one of DMP-10, DMP-30, 2-methylimidazole, and 2-ethyl-4-methylimidazole.

[0022] The present invention provides a method for preparing a biomimetic epoxy adhesive for mica composite materials, which is achieved through the following technical solutions: A method for preparing a bionic epoxy adhesive for mica composite materials comprises the following steps: first preparing hard-core soft-shell particles; then uniformly mixing accurately measured bisphenol A epoxy resin, a curing agent, an accelerator, and the hard-core soft-shell particles, and subjecting the mixture to vacuum degassing for 15-30 minutes to obtain the bionic epoxy adhesive.

[0023] The preparation method of the present invention is relatively simple, has low operation difficulty, and is easy to implement industrial production.

[0024] In summary, this application has the following advantages: 1. The present invention uses hard-core soft-shell particles to toughen and reinforce epoxy resin curing, giving the epoxy resin cured product good impact toughness, while also having good mechanical strength and Young's modulus, better meeting the use requirements of epoxy mica products.

[0025] 2. The epoxy resin of the present invention is mixed with modified bisphenol A epoxy resin, which can improve the processing performance and construction performance of the finished epoxy resin, enhance the heat resistance, flame retardancy, mechanical strength and Young's modulus of the epoxy resin cured product, shorten the curing cycle, and thus improve the output of epoxy mica products.

[0026] 3. The preparation method of the present invention is relatively simple, has low operational difficulty, and is easy to implement large-scale production. DETAILED DESCRIPTION

[0027] In order to further understand the creativity and technical advancement of the present invention, the preferred embodiments of the present invention are discussed in detail below in conjunction with examples and comparative examples.

[0028] Preparation Example 1: The preparation method of the aqueous polyurethane dispersion is as follows: S1. 160 g of PTG 2000 polytetramethylene glycol (Shanxi Sanwei Group Co., Ltd.) and 60 g of 1000 molecular weight polycarbonate diol JSB10 (Jiangsu Institute of Chemical Industry Co., Ltd.) were placed in a 2 L polyurethane reactor (Weihai Huanyu Chemical Machinery Co., Ltd.). Dehydration was performed at 120°C and a vacuum of -0.05 MPa for 1 h to remove water from the polyol, which improves the quality of the waterborne polyurethane dispersion. S2. Adjust the temperature to 90°C, maintain the reactor temperature at 90±0.5°C, add 0.2g of dibutyltin dilaurate T12 (Shandong Wantai Chemical Co., Ltd., tin content 18%), and add 129g of isophorone diisocyanate IPDI dropwise to the 2L polyurethane reactor over 1 hour at a uniform rate. Maintain the reaction temperature at 90±0.5°C for 45 minutes; S3. Adjust the temperature to 70 ± 0.5 ° C, add 11.34g of 1,6-hexanediol and 22.0g of 2,2-dimethylolpropionic acid and 50g of acetone to a 2L polyurethane reactor, and maintain the reaction at 70 ° C for 3 hours; S4. Cool the mixture to 30°C, add 50g of acetone and 16.6g of triethylamine, and neutralize for 15 minutes. Add 560g of deionized water at 4°C at a rate of 120g / min while stirring at high shear speed. After addition, disperse the mixture at high shear speed for 30 minutes. Remove the acetone under reduced pressure at 65°C to obtain an aqueous polyurethane dispersion with a solid content of 41.4% and an average particle size of 52.6nm. For use, adjust the solid content to 30.0% by adding deionized water to obtain the finished aqueous polyurethane dispersion.

[0029] The difference between Preparation Example 2 and Preparation Example 1 is that the preparation method of the aqueous polyurethane dispersion is as follows: S1. 80 g of PTG 2000 polytetramethylene glycol (Shanxi Sanwei Group Co., Ltd.), 40 g of 1000 molecular weight polycarbonate diol JSB10 (Jiangsu Institute of Chemical Industry Co., Ltd.), 84 g of 2000 molecular weight polybutadiene diol Krasol LBH-P 2000 (Mn = 2100, 1,4-cis / 1,4-trans / 1,2-vinyl mass ratio = 12.5 / 22.5 / 65, Cray Valley), and 2.4 g of benzoquinone were placed into a 2 L polyurethane reactor and dehydrated at 120°C and a vacuum of -0.05 MPa for 1 h. S2. Adjust the temperature to 90 ° C, maintain the reactor temperature at 90 ± 0.5 ° C, add 0.2g of dibutyltin dilaurate T12, 129.0g of isophorone diisocyanate IPDI was added dropwise to the 2L polyurethane reactor at a uniform rate within 1 hour, and the reaction was maintained at 90 ± 0.5 ° C for 45 minutes; S3. Adjust the temperature to 70 ± 0.5 ° C, add 14.18g of 1,6-hexanediol and 21.46g of 2,2-dimethylolpropionic acid and 50g of acetone to a 2L polyurethane reactor, and maintain the reaction at 70 ° C for 3 hours; S4. Cool the mixture to 30°C, add 50g of acetone and 16.2g of triethylamine, and neutralize for 15 minutes. Add 610g of deionized water at 4°C at a rate of 120g / min while stirring at high shear speed. After addition, disperse the mixture at high shear speed for 30 minutes. Remove the acetone under reduced pressure at 65°C to obtain an aqueous polyurethane dispersion with a solid content of 38.7% and an average particle size of 80.9nm. For use, adjust the solid content to 30.0% by adding deionized water to obtain the finished aqueous polyurethane dispersion.

[0030] The difference between Preparation Example 3 and Preparation Example 1 is that the preparation method of the aqueous polyurethane dispersion is as follows: S1 and S2 are the same as those in Preparation Example 1, while S3 and S4 are different from those in Preparation Example 1; S3. Adjust the temperature to 70 ± 0.5 ° C, add 11.34 g of 1,6-hexanediol, 22.0 g of 2,2-dimethylolpropionic acid, and 50 g of acetone to a 2L polyurethane reactor, maintain the reaction at 70 ° C for 3 hours, add 26.5 g of hydroxypropyl methacrylate and 1.8 g of benzoquinone, and react at 70 ° C for 1 hour. The NCO content is 0; S4. Cool the mixture to 30°C, add 50g of acetone and 16.6g of triethylamine, and neutralize for 15 minutes. Add 635g of deionized water at 4°C at a rate of 120g / min while stirring at high shear speed. After addition, disperse the mixture at high shear speed for 30 minutes. Remove the acetone under reduced pressure at 65°C to obtain an aqueous polyurethane dispersion with a solid content of 40.1% and an average particle size of 60.4nm. For use, adjust the solid content to 30.0% by adding deionized water to obtain the finished aqueous polyurethane dispersion.

[0031] The difference between Preparation Example 4 and Preparation Example 2 is that the preparation method of the aqueous polyurethane dispersion is as follows: S1 and S2 are the same as those in Preparation Example 1, while S3 and S4 are different from those in Preparation Example 1; S3. Adjust the temperature to 70 ± 0.5 ° C, add 14.18 g of 1,6-hexanediol, 21.46 g of 2,2-dimethylolpropionic acid, and 50 g of acetone to a 2L polyurethane reactor, maintain the reaction at 70 ° C for 3 hours, add 26.5 g of hydroxypropyl methacrylate and 1.8 g of benzoquinone, and react at 70 ° C for 1 hour. The NCO content is 0; S4. Cool the mixture to 30°C, add 50g of acetone and 16.2g of triethylamine, and neutralize for 15 minutes. Add 660g of deionized water at 4°C at a rate of 120g / min while stirring at high shear speed. After addition, disperse the mixture at high shear speed for 30 minutes. Remove the acetone under reduced pressure at 65°C to obtain an aqueous polyurethane dispersion with a solid content of 36.8% and an average particle size of 94.2nm. When ready for use, adjust the solid content to 30.0% by adding deionized water to obtain the finished aqueous polyurethane dispersion.

[0032] Example 1: A biomimetic epoxy adhesive for mica composite materials is prepared from 100 parts of bisphenol A epoxy resin E44, 20 parts of a reactive diluent, 21.6 parts of methyltetrahydrophthalic anhydride, 38.4 parts of trimellitic anhydride, 3 parts of accelerator DMP-30, 1 part of 2-methylimidazole, and 8 parts of hard-core soft-shell microparticles. The reactive diluent is N,N-di(glycidyl)aniline, MF-2133 epoxy diluent, CAS: 2095-06-9, Hubei Zhenbo Chemical Co., Ltd. Methyltetrahydrophthalic anhydride, industrial grade, CAS: 11070-44-3, Shandong Runjin Chemical Technology Co., Ltd. Trimellitic anhydride, CAS: 552-30-7, Macklin's reagent. Accelerator DMP-30, 2,4,6-tris(dimethylaminomethyl)phenol, CAS: 90-72-2, purity ≥ 95%, West Asia's reagent. 2-Methylimidazole, CAS: 693-98-1, purity 99%, Aladdin.

[0033] A method for preparing a biomimetic epoxy adhesive for mica composite materials comprises the following steps: S1, preparation of hard-core soft-shell microparticles. The preparation method of hard-core soft-shell microparticles is as follows: S1.1, nano-palyorcsite NP (i.e., palygorskite nanoparticles, provided by Changzhou Dingbang Mineral Products Co., Ltd., with an average particle size of 500 nm). 50 g of the nano-palyorcsite was weighed and placed in a muffle furnace at 160°C for calcination and activation treatment for 2 h. 50 g of the activated nano-palyorcsite was then placed in 2.0 L of a 2.0 wt% aqueous solution of aminosilane, wherein the aminosilane in the aminosilane aqueous solution was N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane KH792. The mixture was heated to 65°C in a water bath and dispersed under ultrasonic stirring for 60 min at a frequency of 40 kHz / 800 W. The mixture was filtered, washed three times, and dried to obtain amino-modified nano-palyorcsite. S1.2, 50 g of amino-modified nano-palygorskite, 5 g of surfactant (sodium lauryl sulfate), and 245 g of deionized water were dispersed at 800 rpm for 15 min, followed by ultrasonic stirring at 40 kHz / 800 W for 4 min to obtain an amino-modified nano-palygorskite dispersion; S1.3. Maintaining ultrasonic stirring at an ultrasonic frequency of 40 kHz / 800 W and a stirring frequency of 200 r / min, the temperature in a water bath was raised to 65°C. 80 g of the aqueous polyurethane dispersion having a solid content of 30.0% prepared in Preparation Example 1 was added dropwise to the amino-modified palygorskite nanoparticle dispersion at a rate of 3 g / min. After the addition was complete, the reaction was continued for 30 min to obtain a mixed solution. S1.4, maintaining ultrasonic stirring, at an ultrasonic frequency of 40 kHz / 800 W, a stirring frequency of 200 r / min, and 65°C, add 10 g of a 5.0 wt% aqueous tannic acid solution to the mixed solution in step 3 at a dropwise addition rate of 0.1 g / min. After the addition is complete, continue the reaction for 4.0 h, and spray dry to produce hard-core soft-shell microparticles. S2, add accurately measured 100 parts of bisphenol A epoxy resin E44, 20 parts of active diluent - diglycidyl aniline, 21.6 parts of methyltetrahydrophthalic anhydride, 38.4 parts of trimellitic anhydride, 3 parts of accelerator DMP-30, 1 part of 2-methylimidazole, and 8 parts of hard-core soft-shell microparticles into the reactor, stir at 360 r / min for 15 minutes under nitrogen protection, and then perform vacuum degassing treatment for 30 minutes. After filling with nitrogen to restore normal pressure, discharge the material to obtain the product bionic epoxy adhesive.

[0034] The difference between Example 2 and Example 1 is that the bionic epoxy adhesive for mica composite material is composed of 100 parts of bisphenol A epoxy resin E44, 20 parts of active diluent - diglycidyl aniline, 21.6 parts of methyltetrahydrophthalic anhydride, 38.4 parts of trimellitic anhydride, 3 parts of accelerator DMP-30, 1 part of 2-methylimidazole, and 12 parts of hard-core soft-shell particles.

[0035] The difference between Example 3 and Example 1 is that the bionic epoxy adhesive for mica composite material is composed of 100 parts of bisphenol A epoxy resin E44, 20 parts of active diluent - diglycidyl aniline, 21.6 parts of methyltetrahydrophthalic anhydride, 38.4 parts of trimellitic anhydride, 3 parts of accelerator DMP-30, 1 part of 2-methylimidazole, and 16 parts of hard-core soft-shell particles.

[0036] The difference between Example 4 and Example 1 is that the bionic epoxy adhesive for mica composite material is composed of 100 parts of bisphenol A epoxy resin E44, 20 parts of active diluent - diglycidyl aniline, 21.6 parts of methyltetrahydrophthalic anhydride, 38.4 parts of trimellitic anhydride, 3 parts of accelerator DMP-30, 1 part of 2-methylimidazole, and 20 parts of hard-core soft-shell particles.

[0037] The difference between Example 5 and Example 1 is that the preparation method of hard-core soft-shell particles is different, specifically: S1.1, weigh 50 g of nano-palygorskite, place it in a muffle furnace and heat it to 160°C for calcination activation treatment for 2 hours, take 50 g of the activated nano-palygorskite obtained and place it in 2.0 L of an aminosilane aqueous solution with a concentration of 2.0 wt%, the aminosilane in the aminosilane aqueous solution is γ-aminopropyltriethoxysilane KH550, heat it to 65°C in a water bath and ultrasonically stir and disperse it for 60 minutes, the ultrasonic stirring frequency is 40 kHz / 800 W, filter, wash three times, and dry to obtain amino-modified nano-palygorskite, and the remaining steps are the same.

[0038] The difference between Example 6 and Example 1 is that the preparation method of hard-core soft-shell particles is different, specifically: S1.3, maintaining ultrasonic stirring, at an ultrasonic frequency of 40 kHz / 800 W and a stirring frequency of 200 r / min, heating the water bath to 65°C, and adding 40 g of the aqueous polyurethane dispersion with a solid content of 30.0% in Preparation Example 1 to the amino-modified palygorskite nanoparticle dispersion at a dropping rate of 3 g / min. After the addition is completed, the reaction is continued for 30 minutes to obtain a mixed solution, and the remaining steps are the same.

[0039] The difference between Example 7 and Example 1 is that the preparation method of the hard-core soft-shell particles is different, specifically: S1.3, maintaining ultrasonic stirring, at an ultrasonic frequency of 40 kHz / 800 W and a stirring frequency of 200 r / min, heating the water bath to 65°C, and adding 160 g of the aqueous polyurethane dispersion with a solid content of 30.0% in Preparation Example 1 to the amino-modified palygorskite nanoparticle dispersion at a dropping rate of 3 g / min. After the addition is completed, the reaction is continued for 30 minutes to obtain a mixed solution, and the remaining steps are the same.

[0040] The difference between Example 8 and Example 1 is that the preparation method of hard-core soft-shell microparticles is different, specifically: S1.4, maintain ultrasonic stirring, at an ultrasonic frequency of 40kHz / 800W, a stirring frequency of 200r / min and 65°C, add 25g of a 5.0wt% tannic acid aqueous solution to the mixed liquid in step 3 at a dropping rate of 0.1g / min. After the addition is completed, continue the reaction for 4h, and spray dry to obtain hard-core soft-shell microparticles.

[0041] The difference between Example 9 and Example 1 is that the preparation method of hard-core soft-shell microparticles is different, specifically: S1.4, maintain ultrasonic stirring, at an ultrasonic frequency of 40kHz / 800W, a stirring frequency of 200r / min and 65°C, add 50g of a 5.0wt% tannic acid aqueous solution to the mixed liquid in step 3 at a dropping rate of 0.1g / min. After the addition is completed, continue the reaction for 4h, and spray dry to obtain hard-core soft-shell microparticles.

[0042] The difference between Example 10 and Example 1 is that the preparation method of hard-core soft-shell microparticles is different, specifically: S1.4, maintain ultrasonic stirring, at an ultrasonic frequency of 40kHz / 800W, a stirring frequency of 200r / min and 65°C, add 25g of a 5.0wt% dopamine aqueous solution to the mixed solution in step 3 at a dropping rate of 0.1g / min, add 5wt% ammonia water to adjust the pH value to 8.0, then continue the reaction for 4h, and spray dry to obtain hard-core soft-shell microparticles.

[0043] The difference between Example 11 and Example 1 is that the preparation method of hard-core soft-shell particles is different, specifically: S1.3, maintaining ultrasonic stirring, at an ultrasonic frequency of 40 kHz / 800 W and a stirring frequency of 200 r / min, heating the water bath to 65°C, and adding 80 g of the aqueous polyurethane dispersion with a solid content of 30.0% in Preparation Example 2 to the amino-modified palygorskite nanoparticle dispersion at a dropping rate of 3 g / min. After the addition is completed, the reaction is continued for 30 minutes to obtain a mixed solution, and the remaining steps are the same.

[0044] The difference between Example 12 and Example 1 is that the preparation method of the hard-core soft-shell particles is different, specifically: S1.3, maintaining ultrasonic stirring, at an ultrasonic frequency of 40kHz / 800W and a stirring frequency of 200r / min, heating the water bath to 65°C, adding 40g of the aqueous polyurethane dispersion with a solid content of 30.0% in Preparation Example 2 to the amino-modified palygorskite nanoparticle dispersion at a dropping speed of 3g / min, continuing the reaction for 10min after the addition is completed to obtain a mixed solution, and heating the water bath to 85 ℃, 40g of the aqueous polyurethane dispersion with a solid content of 30.0% in Preparation Example 3 was added dropwise to the amino-modified palygorskite nanoparticle dispersion at a dropping speed of 3g / min. At the same time, potassium persulfate emulsion was added dropwise to the amino-modified palygorskite nanoparticle dispersion at a dropping speed of 1g / min. The potassium persulfate emulsion was prepared by mixing 0.5g of potassium persulfate, 1.5g of octylphenol polyoxyethylene ether OP-10, 1g of sodium dodecyl sulfate and 100g of deionized water. After the addition was completed, the reaction was continued for 30min. The remaining steps were the same.

[0045] The difference between Example 13 and Example 12 is that the preparation method of the hard-core soft-shell particles is different, specifically: S1.3, maintaining ultrasonic stirring, at an ultrasonic frequency of 40kHz / 800W and a stirring frequency of 200r / min, heating the water bath to 65°C, adding 90g of the aqueous polyurethane dispersion with a solid content of 30.0% in Preparation Example 2 to the amino-modified palygorskite nanoparticle dispersion at a dropping rate of 3g / min, continuing the reaction for 10min after the addition is completed to obtain a mixed solution, and heating the water bath to 85 ℃, 90g of the aqueous polyurethane dispersion with a solid content of 30.0% in Preparation Example 3 was added dropwise to the amino-modified palygorskite nanoparticle dispersion at a dropping speed of 3g / min. At the same time, potassium persulfate emulsion was added dropwise to the amino-modified palygorskite nanoparticle dispersion at a dropping speed of 1g / min. The potassium persulfate emulsion was prepared by mixing 0.5g of potassium persulfate, 1.5g of octylphenol polyoxyethylene ether OP-10, 1g of sodium dodecyl sulfate and 100g of deionized water. After the addition was completed, the reaction was continued for 30min. The remaining steps were the same.

[0046] The difference between Example 14 and Example 12 is that the preparation method of the hard-core soft-shell particles is different, specifically: S1.3, maintaining ultrasonic stirring, at an ultrasonic frequency of 40kHz / 800W and a stirring frequency of 200r / min, heating the water bath to 65°C, adding 90g of the aqueous polyurethane dispersion with a solid content of 30.0% in Preparation Example 2 to the amino-modified palygorskite nanoparticle dispersion at a dropping speed of 3g / min, continuing the reaction for 10min after the addition is completed to obtain a mixed solution, and heating the water bath to 85 ℃, 90g of the aqueous polyurethane dispersion with a solid content of 30.0% in Preparation Example 4 was added dropwise to the amino-modified palygorskite nanoparticle dispersion at a dropping speed of 3g / min. At the same time, potassium persulfate emulsion was added dropwise to the amino-modified palygorskite nanoparticle dispersion at a dropping speed of 1g / min. The potassium persulfate emulsion was prepared by mixing 0.5g of potassium persulfate, 1.5g of octylphenol polyoxyethylene ether OP-10, 1g of sodium dodecyl sulfate and 100g of deionized water. After the addition was completed, the reaction was continued for 30min. The remaining steps were the same.

[0047] The difference between Example 15 and Example 1 is that the bionic epoxy adhesive for mica composite material is composed of 90 parts of bisphenol A epoxy resin E44, 10 parts of modified bisphenol A epoxy resin, 20 parts of active diluent - diglycidyl aniline, 20.5 parts of methyltetrahydrophthalic anhydride, 36.5g of trimellitic anhydride, 3 parts of accelerator DMP-30, 1 part of 2-methylimidazole, and 8 parts of hard-core soft-shell particles.

[0048] The preparation method of modified bisphenol A epoxy resin is as follows: Step 1: Dissolve 16.74 g of epoxy resin E20 (Baling Petrochemical CYD-011) in 80 g of acetone and mix well to obtain a mixed solution A; at the same time, dissolve 11.52 g of 1,3,5-tris(3-isocyanatomethylphenyl)-1,3,5-triazine-2,4,6(1H,2H,5H)-trione (molecular weight: 523.48, CAS: 26603-40-7) in 40 g of acetone and mix well to obtain a mixed solution B; Step 2: Add 0.02 g of dibutyltin dilaurate to mixed solution A and mix well. Heat the mixture in a water bath to 60° C. and add mixed solution B to mixed solution A at a rate of 3 g / min. After the addition of mixed solution B, cool the mixture to 50° C. and continue the reaction at 50° C. for 1.0 h to obtain mixed solution C. Step 2: Heat the water bath to 60°C, add 3.84g of methyl ethyl ketone oxime to the mixed solution C, react at 60°C for 2h until the -NCO content is 0, remove acetone by vacuum distillation to obtain a solid, grind and crush to obtain the finished modified bisphenol A epoxy resin powder.

[0049] The difference between Example 16 and Example 15 is that the bionic epoxy adhesive for mica composite material is composed of 85 parts of bisphenol A epoxy resin E44, 15 parts of modified bisphenol A epoxy resin, 20 parts of active diluent-diglycidyl aniline, 20.0 parts of methyltetrahydrophthalic anhydride, 35.6g of trimellitic anhydride, 3 parts of accelerator DMP-30, 1 part of 2-methylimidazole, and 8 parts of hard-core soft-shell particles.

[0050] The difference between Example 17 and Example 1 is that the bionic epoxy adhesive for mica composite material is composed of 80 parts of bisphenol A epoxy resin E44, 20 parts of modified bisphenol A epoxy resin, 20 parts of active diluent - diglycidyl aniline, 19.4 parts of methyltetrahydrophthalic anhydride, 34.6 parts of trimellitic anhydride, 3 parts of accelerator DMP-30, 1 part of 2-methylimidazole, and 8 parts of hard-core soft-shell particles.

[0051] The difference between Example 18 and Example 1 is that the bionic epoxy adhesive for mica composite material is composed of 75 parts of bisphenol A epoxy resin E44, 25 parts of modified bisphenol A epoxy resin, 20 parts of active diluent - diglycidyl aniline, 18.9 parts of methyltetrahydrophthalic anhydride, 33.6 parts of trimellitic anhydride, 3 parts of accelerator DMP-30, 1 part of 2-methylimidazole, and 8 parts of hard-core soft-shell particles.

[0052] The difference between Comparative Example 1 and Example 1 is that the bionic epoxy adhesive for mica composite material consists of 100 parts of bisphenol A epoxy resin E44, 20 parts of active diluent - diglycidyl aniline, 21.6 parts of methyltetrahydrophthalic anhydride, 38.4 parts of trimellitic anhydride, 3 parts of accelerator DMP-30, and 1 part of 2-methylimidazole.

[0053] The difference between Comparative Example 2 and Example 1 is that the bionic epoxy adhesive for mica composite material consists of 100 parts of bisphenol A epoxy resin E44, 20 parts of active diluent - diglycidyl aniline, 21.6 parts of methyltetrahydrophthalic anhydride, 38.4 parts of trimellitic anhydride, 3 parts of accelerator DMP-30, 1 part of 2-methylimidazole, and 4 parts of hard-core soft-shell particles.

[0054] Comparative Example 3 differs from Example 1 in that the biomimetic epoxy adhesive for mica composite materials is composed of 100 parts of bisphenol A epoxy resin E44, 20 parts of diglycidyl aniline (active diluent), 21.6 parts of methyltetrahydrophthalic anhydride, 38.4 parts of trimellitic anhydride, 3 parts of accelerator DMP-30, 1 part of 2-methylimidazole, and 8 parts of a core-shell rubber epoxy resin toughening agent. The core-shell rubber epoxy resin toughening agent is Japanese Kanebuchi MX-962, produced by Jining Tangyi Chemical Co., Ltd.

[0055] Comparative Example 4 differs from Example 1 in that the biomimetic epoxy adhesive for mica composite materials consists of 100 parts of bisphenol A epoxy resin E44, 20 parts of diglycidyl aniline (a reactive diluent), 21.6 parts of methyltetrahydrophthalic anhydride, 38.4 parts of trimellitic anhydride, 3 parts of accelerator DMP-30, 1 part of 2-methylimidazole, and 8 parts of nano-palyorcsite. The nano-palyorcsite is palygorskite nanoparticles with an average particle size of 500 nm, provided by Changzhou Dingbang Mineral Products Co., Ltd.

[0056] Epoxy mica insulation sheets were prepared using the epoxy adhesives described in Examples 1-18 and Comparative Examples 1-4, respectively, to produce Test Samples 1-18 and Comparative Samples 1-4. The epoxy mica insulation sheets were prepared as follows: 18 parts by weight of the epoxy adhesive was uniformly mixed with 82 parts of 325-mesh phlogopite mica, followed by vacuum degassing for 15 minutes. The mixture was then poured into a mold (a release agent was sprayed onto the mold cavity), heat-cured at 110°C for 25 minutes, naturally cooled to room temperature, and demolded to produce the epoxy mica insulation sheet.

[0057] The following four performance tests were performed on test specimens 1-18 and comparative specimens 1-4: 1. Tensile strength was measured in accordance with ISO 527 using dumbbell-shaped specimens at a rate of 1-5 mm / min. 2. Flexural strength was measured in accordance with ISO 178 using the three-point bend method with a span of 16 x specimen thickness. 3. Impact strength was measured in accordance with ISO 179 using the Charpy notched impact method. 4. Tensile elongation at break was measured in accordance with ISO 527. 5. Dielectric strength was measured in accordance with IEC 60243 using the short-time voltage-increase method with an electrode diameter of 6 mm.

[0058] Table 1: Test performance parameters of epoxy mica materials in Examples 1-4 and Comparative Examples 1-4

[0059] Combining Examples 1-4 and Comparative Examples 1-4 with Table 1, it can be seen that the addition of hard-core soft-shell particles can improve the mechanical properties of the epoxy mica insulation board and enhance the impact toughness of the epoxy mica insulation board. When the addition amount of the hard-core soft-shell particles is 8-20 parts, the prepared epoxy mica insulation board has good mechanical properties and impact toughness.

[0060] Table 2: Test performance parameters of epoxy mica materials in Example 1 and Examples 5-10

[0061] Combining Example 1 and Example 5 with Table 2, it can be seen that the hard-core soft-shell particles synthesized from amino-modified nano-palygorskite modified with KH792 have a relatively good effect on improving the mechanical properties and impact toughness of the epoxy mica insulation board.

[0062] Combining Example 1 with Examples 6-7 and Table 2, it can be seen that the amount of the aqueous polyurethane dispersion with a solid content of 30.0% in Preparation Example 1 added in the hard-core soft-shell particle synthesis process S1.3 affects the soft shell thickness of the hard-core soft-shell particles. The prepared hard-core soft-shell particles with different soft shell thicknesses have an impact on the mechanical properties and impact toughness of the epoxy mica insulation board. Comparison of Example 1 with Examples 6-7 shows that the amount of the aqueous polyurethane dispersion with a solid content of 30.0% in Preparation Example 1 added in the hard-core soft-shell particle synthesis process S1.3 is preferably controlled to 80g-100g. Excessive addition will increase the production cost of the hard-core soft-shell particles.

[0063] From Example 1 and Examples 8-9 and Table 2, it can be seen that the amount of tannic acid aqueous solution added at a concentration of 5.0wt% in the hard-core soft-shell particle synthesis process S1.4 affects the surface properties of the hard-core soft-shell particles. As the amount of tannic acid aqueous solution added increases, the tannic acid content on the surface of the synthesized hard-core soft-shell particles increases, and the crosslinking density between the hard-core soft-shell particles and the epoxy adhesive groups increases. The mechanical properties of the prepared epoxy mica insulation board show an upward trend, while the impact toughness shows a trend of first increasing and then decreasing. In terms of impact toughness, excessive crosslinking density will lead to a decrease in impact toughness and elongation-fracture properties. Therefore, the amount of tannic acid aqueous solution added at a concentration of 5.0wt% in S1.4 is preferably controlled to 20-30g.

[0064] Table 3: Test performance parameters of epoxy mica materials in Example 1 and Examples 11-14

[0065] Combining Example 1 and Comparative Examples 11-12 with Table 3, it can be seen that the hard-core soft-shell particles contain polybutadiene glycol molecular segments in the soft shell, and the hard-core soft-shell particles prepared have a relatively better effect on improving the toughness of epoxy mica insulation board materials. The soft shell of the hard-core soft-shell particles used in Example 12 is composed of the polyurethane latex WPU2 in Preparation Example 2 and the polyurethane latex WPU3 in Preparation Example 3. The double bonds of the polybutadiene glycol molecular segments in WPU2 undergo polymerization reaction with the double bonds in the hydroxypropyl methacrylate in WPU3 under free radical initiation to form a hard-core soft-shell particle material with nano-palygorskite as the core, WPU2 as the elastic intermediate layer, and WPU3 as the soft shell. The epoxy-epoxy adhesive prepared therefrom has a relatively better comprehensive improvement effect on the toughness and mechanical properties of epoxy mica insulation board materials.

[0066] Combining Example 13 with Comparative Example 14 and Table 3, it can be seen that the epoxy-epoxy adhesive prepared from the hard-core, soft-shell particles in Example 14 significantly improves the toughness and tensile strength of the epoxy-mica insulation board, while slightly decreasing the flexural strength of the epoxy-mica insulation board. The hard-core, soft-shell particles synthesized in Example 14 are the optimal hard-core, soft-shell particle material in the present invention.

[0067] Table 4: Test performance parameters of epoxy mica materials in Example 1 and Examples 15-18

[0068] From Example 1 and Comparative Examples 15-18 and Table 4, it can be seen that the addition of modified bisphenol A epoxy resin can improve the tensile strength and flexural strength of the epoxy mica insulation board. As for the impact toughness of the epoxy mica insulation board, the addition amount of modified bisphenol A epoxy resin is 10-15 parts, which has a positive effect on the impact toughness of the epoxy mica insulation board. However, when the addition amount of modified bisphenol A epoxy resin is greater than 15 parts, the impact toughness of the epoxy mica insulation board shows a downward trend. Therefore, the addition amount of modified bisphenol A epoxy resin is preferably 15 parts, which improves the mechanical properties and impact toughness of the epoxy mica insulation board.

[0069] In summary, the present invention uses hard-core soft-shell particles to toughen and reinforce epoxy resin curing, giving it good impact toughness while also having good mechanical strength and Young's modulus, which better meets the use requirements of epoxy mica products.

[0070] It should be noted that this specific embodiment is merely an explanation of the technical solution of the present invention and is not a limitation of the present invention. After reading this specification, those skilled in the art may make non-creative modifications to this embodiment as needed, but as long as they are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A biomimetic epoxy adhesive for mica composite materials, characterized by: The invention is prepared from the following raw materials in parts by weight: 100 parts of bisphenol A epoxy resin, 50-75 parts of curing agent, 10-20 parts of epoxy reactive diluent, 3-6 parts of accelerator, and 8-20 parts of hard-core soft-shell particles; The hard-core soft-shell particles have palygorskite nanoparticles as hard cores and PU as soft shells. Dopamine or tannic acid is grafted onto the soft shells of the hard-core soft-shell particles.

2. The biomimetic epoxy adhesive for mica composite materials according to claim 1, characterized in that: The preparation method of the hard-core soft-shell microparticles is as follows: Step 1: calcining and activating the palygorskite nanoparticles, and performing surface amination modification on the activated palygorskite nanoparticles to obtain amino-modified palygorskite nanoparticles; Step 2: uniformly dispersing the amino-modified palygorskite nanoparticles, a surfactant, and deionized water at high speed, and then ultrasonically stirring for 3-6 minutes to obtain an amino-modified palygorskite nanoparticle dispersion; Step 3: maintaining ultrasonic stirring and heating to 50-85° C., adding an aqueous polyurethane dispersion dropwise to the amino-modified palygorskite nanoparticle dispersion, wherein the mass ratio of the amino-modified palygorskite nanoparticles to the polyurethane latex particles in the aqueous polyurethane dispersion is 1:(0.1-2), and continuing the reaction for 15-30 minutes after the addition is completed; Step 4: maintaining ultrasonic stirring and a temperature of 50-85°C, adding a dopamine aqueous solution or a tannic acid aqueous solution to the mixed solution in step 3, wherein the mass ratio of amino-modified palygorskite nanoparticles to dopamine or tannic acid is 1:(0.01-0.05), continuing the reaction for 2-4 hours after the addition is completed, and drying to obtain hard-core soft-shell particles.

3. The biomimetic epoxy adhesive for mica composite materials according to claim 2, characterized in that: The first step is to place the palygorskite nanoparticles in a muffle furnace and heat them to 140-160° C. for calcination activation treatment for 1-2 hours, take 5-10 parts by mass of the activated palygorskite nanoparticles and place them in 200-400 parts by mass of an aminosilane aqueous solution with a concentration of 0.5-5wt%, wherein the aminosilane in the aminosilane aqueous solution is at least one of γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropylmethyldiethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, and N-β-(aminoethyl)-y-aminopropylmethyldimethoxysilane, heat the water bath to 60-70° C., and perform ultrasonic stirring and dispersion treatment for 30-60 minutes, filter, wash multiple times, and dry to obtain amino-modified palygorskite nanoparticles.

4. The biomimetic epoxy adhesive for mica composite materials according to claim 2, characterized in that: The surfactant in step 2 is at least one of sodium lauryl sulfate, sodium didodecylphenyl ether disulfonate, octylphenol polyoxyethylene ether OP-10, sodium hexadecyl sulfate, sodium dodecyl polyoxyethylene ether sulfate, sodium dodecylbenzenesulfonate, sodium dodecylsulfonate, and sodium rosinate.

5. The biomimetic epoxy adhesive for mica composite materials according to claim 2, characterized in that: The aqueous polyurethane dispersion comprises aqueous polyurethane dispersion A and aqueous polyurethane dispersion B. The end-capping functional group of the polyurethane particle in the aqueous polyurethane dispersion A is -NCO, and the polymer main chain of the polyurethane particle contains an active double bond; the end of the polyurethane particle in the aqueous polyurethane dispersion B is capped with hydroxy acrylate or hydroxy methacrylate.

6. The biomimetic epoxy adhesive for mica composite materials according to claim 5, characterized in that: The third step comprises the following steps: heating the mixture to 50-65° C. under ultrasonic stirring, dripping aqueous polyurethane dispersion A into the amino-modified palygorskite nanoparticle dispersion, wherein the mass ratio of the amino-modified palygorskite nanoparticles to the polyurethane latex particles in the aqueous polyurethane dispersion A is 1:(0.1-0.5), and continuing to react for 5-10 minutes after the dripping of the aqueous polyurethane dispersion A is completed; heating the mixture to 80-65° C. under ultrasonic stirring, and simultaneously dripping aqueous polyurethane dispersion B and potassium persulfate emulsion into the amino-modified palygorskite nanoparticle dispersion, wherein the potassium persulfate emulsion is prepared from 0.4-0.6 parts of potassium persulfate, 0.8-1.6 parts of octylphenol polyoxyethylene ether OP-10, 0.8-1.6 parts of sodium dodecylsulfonate, and 100 parts of deionized water, wherein the mass ratio of the amino-modified palygorskite nanoparticles to the polyurethane latex particles in the aqueous polyurethane dispersion B is 1:(0.8-1.6), and continuing to react for 15-30 minutes after the dripping is completed.

7. The biomimetic epoxy adhesive for mica composite materials according to claim 1, characterized in that: The bisphenol A epoxy resin is composed of bisphenol A epoxy resin E44 and modified bisphenol A epoxy resin in a mass ratio of 100:(10-25); the modified bisphenol A epoxy resin is made of bisphenol A epoxy resin E20, 1,3,5-tris(3-isocyanatomethylphenyl)-1,3,5-triazine-2,4,6(1H,2H,5H)-trione, dibutyltin dilaurate, methyl ethyl ketone oxime, and a polar solvent.

8. The biomimetic epoxy adhesive for mica composite materials according to claim 7, characterized in that: The preparation method of the modified bisphenol A epoxy resin is as follows: Step 1: dissolving epoxy resin E20 in acetone to form an epoxy resin E20 solution; Step 2: Add 1,3,5-tris(3-isocyanatomethylphenyl)-1,3,5-triazine-2,4,6(1H,2H,5H)-trione and dibutyltin dilaurate to the epoxy resin E20 solution, wherein the molar amount of -NCO in the 1,3,5-tris(3-isocyanatomethylphenyl)-1,3,5-triazine-2,4,6(1H,2H,5H)-trione is (3-3.03):1, and the mass ratio of the dibutyltin dilaurate to the epoxy resin E20 is 1:(800-2000), and the temperature is raised to 50-60° C. and the reaction is carried out for 1-2 hours; Step 2: maintaining the temperature at 50-60° C., adding methyl ethyl ketone oxime, wherein the molar ratio of the methyl ethyl ketone oxime to the molar ratio of the 1,3,5-tris(3-isocyanatomethylphenyl)-1,3,5-triazine-2,4,6(1H,2H,5H)-trione is (2-2.02):1, reacting at 50-60° C. for 2-4 hours until the -NCO content is 0, and removing acetone by reduced pressure distillation to obtain the finished modified bisphenol A epoxy resin.

9. The biomimetic epoxy adhesive for mica composite materials according to claim 7, characterized in that: The curing agent is at least one of homomethyltetrahydrophthalic anhydride, pyromellitic anhydride dianhydride, phthalic anhydride, trimellitic anhydride, benzophenonetetracarboxylic dianhydride, and maleic anhydride; the accelerator is at least one of DMP-10, DMP-30, 2-methylimidazole, and 2-ethyl-4-methylimidazole.

10. A method for preparing a biomimetic epoxy adhesive for mica composite materials according to any one of claims 1 to 9, characterized in that: The following steps are involved: First, hard-core soft-shell particles are prepared; then, accurately measured bisphenol A epoxy resin, curing agent, accelerator, and hard-core soft-shell particles are evenly mixed and vacuum degassing is performed for 15-30 minutes to obtain a bionic epoxy adhesive product.

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