An anti-aging electrical epoxy resin and its preparation method

Abstract

The present invention belongs to the technical field of electrical epoxy resin materials, and specifically relates to an anti-aging electrical epoxy resin and a preparation method thereof. The composition of the epoxy resin comprises the following raw materials in parts by weight: 70-80 parts of epoxy resin, 3-5 parts of modified nano-silica, 1-3 parts of amino-functionalized graphene, 5-8 parts of polyurethane, 0.5-1 part of methyltriethoxysilane, 0.1-0.5 part of sodium dodecyl sulfate, 0.5-1 part of antioxidant, and 0.5-1 part of ultraviolet absorber. In the present invention, nano-silica is modified by silane and amino-functionalized graphene is used to improve the anti-aging and corrosion resistance of epoxy resin. Nano-silica enhances hardness and rigidity, and amino-functionalized graphene improves toughness and thermal conductivity. The two act synergistically to form multiple physical barriers, reducing the penetration of aging factors and corrosive media. The surface is treated with methyltriethoxysilane for hydrophobic treatment to further improve weather resistance and moisture resistance.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrical epoxy resin materials, and particularly relates to an anti-aging electrical epoxy resin and a preparation method thereof. Background Art

[0002] Anti-aging electrical epoxy resins are widely used in fields such as electronics, electricity, and high-voltage insulation. They are mainly used to manufacture electronic packaging materials, electrical insulation materials, and coatings to protect electronic components from environmental factors and improve the service life of equipment. Epoxy resins have excellent mechanical properties, chemical resistance, good electrical insulation properties, and adhesive properties, so they are widely used in electronic and electrical equipment. However, the disadvantages of epoxy resins are their high brittleness, poor impact resistance, and easy aging when exposed to high temperature, ultraviolet light, and humid environments for a long time. These problems will affect their durability and stability in electrical applications. Traditional epoxy resins are prone to thermal degradation at high temperatures, resulting in a decline in mechanical and electrical properties; ultraviolet light and moisture will cause chemical aging of epoxy resins, making them lose their original properties; under long-term stress, epoxy resins are prone to fatigue cracks, affecting their service life; under the action of oxygen and free radicals, epoxy resins will undergo oxidative degradation, resulting in a decline in material properties; certain chemical substances (such as acids, alkalis, solvents) will corrode epoxy resins, affecting their long-term stability. In addition, the aging of epoxy resins mainly includes two forms: physical aging and chemical aging. Physical aging is mainly manifested as the embrittlement, cracking, and decline in mechanical properties of the material. This is usually due to factors such as temperature changes and stress during the use of the material; chemical aging is mainly manifested as the degradation, reduction in crosslinking density, and decline in performance of the material. This is usually due to the erosion of environmental factors such as oxygen, ultraviolet light, and moisture during the use of the material. After aging, the mechanical strength, electrical properties, and corrosion resistance of the resin will significantly decline, easily leading to problems such as insulation failure of equipment, thus seriously affecting the safety and service life of the system. Therefore, based on the above problems, it is extremely necessary to develop an anti-aging and corrosion-resistant electrical epoxy resin. Summary of the Invention

[0003] Aiming at the defects of the prior art, the purpose of the present invention is to provide an anti-aging electrical epoxy resin and a preparation method thereof.

[0004] The technical effects of the present invention are achieved through the following technical solutions: An anti-aging electrical epoxy resin, the composition of which includes the following raw materials in parts by weight: 70-80 parts of epoxy resin, 3-5 parts of modified nano-silica, 1-3 parts of amino-functionalized graphene, 5-8 parts of polyurethane, 0.5-1 part of methyltriethoxysilane, 0.1-0.5 part of sodium dodecyl sulfate, 0.5-1 part of antioxidant, and 0.5-1 part of ultraviolet absorber.

[0005] Preferably, the epoxy resin is bisphenol A epoxy resin.

[0006] Preferably, the antioxidant is any one of 2,6-di-tert-butyl-p-cresol, ascorbic acid, N-phenyl-α-naphthylamine, and dilauryl thiodipropionate.

[0007] Preferably, the ultraviolet absorber is any one of 2-hydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, benzyl salicylate, and phenyl salicylic acid.

[0008] Preferably, the specific preparation steps of the modified nano-silica are as follows:

[0009] A1: Add nano-silica into absolute ethanol, perform ultrasonic dispersion treatment at 100 - 200W for 30 - 60 min to obtain a nano-silica dispersion; add γ-glycidoxypropyltrimethoxysilane into absolute ethanol, stir and mix evenly, then slowly dropwise add deionized water and acetic acid, and stir and react at 200 - 300 rpm for 10 - 30 min to obtain a coupling agent solution;

[0010] A2: Slowly add the coupling agent solution prepared in step A1 into the nano-silica dispersion prepared in step A1, stir and react at a rotation speed of 300 - 500 rpm at room temperature for 12 h, then centrifuge, wash repeatedly with deionized water 5 times, and vacuum dry at 60 - 80 °C for 12 - 24 h to obtain modified nano-silica;

[0011] Preferably, in step A1, the dosage ratio of the nano-silica to the absolute ethanol is 1 g:40 - 50 mL; the dosage ratio of the γ-glycidoxypropyltrimethoxysilane, absolute ethanol, deionized water, and acetic acid is 1 g:15 - 20 mL:0.5 - 0.6 mL:0.04 - 0.05 mL;

[0012] Preferably, in step A2, the volume dosage ratio of the coupling agent solution to the nano-silica dispersion is 0.02 - 0.03:1.

[0013] Preferably, the specific preparation steps of the amino-functionalized graphene are as follows:

[0014] B1: Add graphite powder into a flask, slowly add concentrated sulfuric acid and concentrated phosphoric acid, control the temperature at 0 - 5 °C, stir and disperse evenly, raise the temperature to 10 °C, then slowly add potassium permanganate. After the addition is completed, raise the temperature to 35 - 40 °C, stir and react for 12 - 24 h, then slowly add deionized water for dilution, then add hydrogen peroxide, centrifuge, wash repeatedly with deionized water and 1M HCl solution 3 times, and vacuum dry at 60 °C for 12 - 24 h to obtain graphene oxide;

[0015] B2: Disperse the graphene oxide prepared in step B1 in dimethyl sulfoxide, and perform ultrasonic dispersion treatment at 100 - 150 W for 30 - 60 min to obtain a graphene oxide dispersion; control the temperature at 0 - 5 °C, slowly add 3-aminopropyltriethoxysilane to the graphene oxide dispersion. After the addition is completed, raise the temperature to 60 °C, continuously stir for 12 - 24 h, centrifuge, wash repeatedly with deionized water and ethanol 3 times, and vacuum dry at 60 °C for 12 - 24 h to obtain amino-functionalized graphene;

[0016] Preferably, in step B1, the dosage ratio of the graphite powder, concentrated sulfuric acid, and concentrated phosphoric acid is 1 g: 20 - 25 mL: 2 - 3 mL; the dosage ratio of the potassium permanganate, deionized water, hydrogen peroxide, and graphite powder is 3 g: 80 - 100 mL: 3 - 4 mL: 1 g;

[0017] Preferably, in step B2, the dosage ratio of the graphene oxide, dimethyl sulfoxide, and 3-aminopropyltriethoxysilane is 3 - 5 mg: 1 mL: 0.04 - 0.05 mL.

[0018] Preferably, on the other hand, the present invention provides a method for preparing an anti-aging electrical epoxy resin, and the specific preparation steps are as follows:

[0019] S1: Add the modified nano-silica and amino-functionalized graphene to the epoxy resin according to the weight ratio, stir at 1000 - 1500 rpm for 40 - 60 min. After uniform dispersion, add sodium dodecyl sulfate, stir at 800 - 1200 rpm for 15 - 30 min, and then add polyurethane, antioxidant, and ultraviolet absorber, stir at 500 - 800 rpm for 15 - 30 min to obtain a mixed raw material;

[0020] S2: Cure the mixed raw material prepared in step S1 at 80 °C for 2 h, and then cure at 120 °C for 2 h to obtain a cured material; add methyltriethoxysilane to 100 times the weight of anhydrous ethanol, add half of the weight of the substrate of deionized water, stir and react at 300 - 500 rpm for 15 - 30 min to obtain a hydrolysis solution;

[0021] S3: Spray the hydrolysis solution prepared in step S2 onto the surface of the cured material prepared in step S2. After the spraying is completed, vacuum dry at 60 - 80 °C for 1 - 2 h to obtain an epoxy resin;

[0022] Preferably, in step S3, the spraying operation parameters are 0.1 - 0.3 MPa, distance 15 - 20 cm, speed 20 - 30 cm / s, stand still for 5 - 10 min after each spraying, and spray 3 times in total.

[0023] The beneficial effects of the present invention are as follows:

[0024] In the present invention, by introducing silane-modified nano-silica and aminated graphene, the anti-aging and corrosion resistance properties of the epoxy resin matrix are significantly improved. Due to its high specific surface area and surface energy, nano-silica is prone to agglomeration in the epoxy resin matrix, resulting in uneven dispersion. By surface-modifying it with a silane coupling agent (γ-glycidoxypropyltrimethoxysilane), organic functional groups such as epoxy groups are introduced onto the surface of nano-silica, turning its surface from hydrophilic to organophilic, and significantly improving its dispersibility and compatibility in epoxy resin. One end of the silane coupling agent (the siloxane group) generates silanol through hydrolysis and undergoes a dehydration condensation reaction with the hydroxyl groups on the surface of nano-silica to form a stable Si-O-Si covalent bond. The epoxy group at the other end can react with the active groups in the epoxy resin matrix to further achieve cross-linking. Through this bifunctional structure, nano-silica can be firmly bound in the matrix, and at the same time, the interfacial bonding force between the filler and the matrix is significantly enhanced, reducing interfacial defects and stress concentration, thereby improving the mechanical properties and anti-aging ability of the epoxy resin.

[0025] In the present invention, amination modification makes the surface of graphene more compatible with epoxy resin. The amino group can undergo a chemical reaction with the epoxy group to form a stable covalent bond, improving the dispersibility and compatibility of graphene in epoxy resin, enhancing the interfacial bonding force, reducing interfacial defects, and improving the stress transfer efficiency. In addition, the high thermal conductivity and electrical conductivity of graphene itself can form an effective thermal conduction network in the matrix, significantly improving the heat dissipation performance of the material and preventing material aging caused by high temperature. At the same time, the lamellar structure of graphene can form a physical barrier to delay the penetration of oxygen, moisture, and corrosive media, and amination further enhances the barrier effect, enabling the material to have a longer service life in a corrosive environment. Silane-modified nano-silica and aminated graphene are uniformly dispersed in the epoxy resin matrix to form multiple physical barriers, synergistically slowing down the penetration of aging factors and corrosive media. Nano-silica enhances the hardness and rigidity of the material, while aminated graphene improves toughness and thermal conductivity. The synergistic effect of the two endows the material with high strength, high toughness, and excellent thermal stability, further enhancing the durability of the material in an electrical application environment. At the same time, these added auxiliaries effectively reduce the penetration of oxygen and ultraviolet rays, slowing down the consumption rate of antioxidants and ultraviolet absorbers, making their chemical protection inside the material more durable. The modified nano-silica forms a strong chemical bond with the matrix through the silane coupling agent, and aminated graphene forms additional hydrogen bonds between the matrix and nano-silica through the amino group. The multiple interfacial bonding mechanisms significantly improve the compatibility between the nano-filler and the matrix and reduce interfacial defects.

[0026] In the present invention, hydrophobic treatment is carried out on the material surface using methyltriethoxysilane (MTES). The silanol groups generated by hydrolysis form Si-O-Si bonds with each other and self-assemble to form a uniform hydrophobic coating. The unreacted silanol groups of the MTES coating can form a well-compatible interface with the glycidyl ether groups of the modified nano-silica, and the amino groups of the amino-functionalized graphene can also react with the silanol groups in the coating to form stable chemical bonds, thereby achieving good bonding among the three, further improving the dispersibility and compatibility of the filler in the matrix, and effectively avoiding the degradation of material properties caused by poor interfaces. Such a silane-based hydrophobic coating can not only effectively delay the penetration of moisture and corrosive media, but also adhere to the surface of the epoxy resin through physical adsorption and hydrogen bonding, further improving the weather resistance and moisture resistance of the overall material. The outer hydrophobic treatment blocks the entry of moisture and corrosive substances, while the inner nano-fillers further slow down the diffusion of the remaining permeates. The combined action of the inner and outer layers significantly improves the corrosion resistance of the material. Brief Description of the Drawings

[0027] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only those of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0028] Figure 1 It is a graph showing the change in tensile strength under ultraviolet aging test of the epoxy resins prepared in Example 2 of the present invention and Comparative Examples 1-4;

[0029] Figure 2 It is a heat distortion temperature graph of the epoxy resins prepared in Example 2 of the present invention and Comparative Examples 1-4;

[0030] Figure 3 It is a graph showing the change in tensile strength under corrosion resistance test of the epoxy resins prepared in Example 2 of the present invention and Comparative Examples 1-4. Detailed Description of the Embodiments

[0031] The following will combine the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention. It should be noted that unless otherwise specified, the raw materials involved in the present invention are purchased through conventional commercial channels.

[0032] Example 1: An anti-aging electrical epoxy resin, the composition of which comprises the following raw materials in parts by weight: 70 parts of epoxy resin, 3 parts of modified nano-silica, 1 part of amino-functionalized graphene, 5 parts of polyurethane, 0.5 part of methyltriethoxysilane, 0.1 part of sodium dodecyl sulfate, 0.5 part of antioxidant, and 0.5 part of ultraviolet absorber.

[0033] The specific preparation steps of the modified nano-silica are as follows:

[0034] A1: Add 10 g of nano-silica to 400 mL of absolute ethanol, and perform ultrasonic dispersion treatment at 100 W for 60 min to obtain a nano-silica dispersion; add 10 g of γ-glycidoxypropyltrimethoxysilane to 150 mL of absolute ethanol, stir and mix evenly, then slowly dropwise add 5 mL of deionized water and 0.4 mL of acetic acid, and stir and react at 200 rpm for 30 min to obtain a coupling agent solution;

[0035] A2: Slowly add 16 mL of the coupling agent solution prepared in step A1 to 400 mL of the nano-silica dispersion prepared in step A1, stir and react at a rotation speed of 300 rpm at room temperature for 12 h, then centrifuge, wash repeatedly with deionized water 5 times, and vacuum dry at 60 °C for 24 h to obtain modified nano-silica;

[0036] The specific preparation steps of the amino-functionalized graphene are as follows:

[0037] B1: Add 10 g of graphite powder to a flask, slowly add 200 mL of concentrated sulfuric acid and 20 mL of concentrated phosphoric acid, control the temperature at 5 °C, stir and disperse evenly, raise the temperature to 10 °C, then slowly add 30 g of potassium permanganate. After the addition is completed, raise the temperature to 35 °C, stir and react for 24 h, then slowly add 800 mL of deionized water for dilution, then add 30 mL of hydrogen peroxide, centrifuge, wash repeatedly with deionized water and 1M HCl solution 3 times, and vacuum dry at 60 °C for 12 h to obtain graphene oxide;

[0038] B2: Disperse 900 mg of the graphene oxide prepared in step B1 in 300 mL of dimethyl sulfoxide, perform ultrasonic dispersion treatment at 100 W for 60 min to obtain a graphene oxide dispersion; control the temperature at 5 °C, slowly dropwise add 12 mL of 3-aminopropyltriethoxysilane to the graphene oxide dispersion. After the dropwise addition is completed, raise the temperature to 60 °C, continuously stir for 12 h, centrifuge, wash repeatedly with deionized water and ethanol 3 times, and vacuum dry at 60 °C for 12 h to obtain amino-functionalized graphene;

[0039] The specific preparation steps of the anti-aging electrical epoxy resin are as follows:

[0040] S1: Add modified nano-silica and aminated graphene into bisphenol A epoxy resin according to the weight ratio. Stir at 1000 rpm for 60 min. After uniform dispersion, add sodium dodecyl sulfate and stir at 800 rpm for 30 min. Then add polyurethane, 2,6-di-tert-butyl-p-cresol and 2-hydroxy-4-methoxybenzophenone, and stir at 500 rpm for 30 min to obtain a mixed raw material;

[0041] S2: Cure the mixed raw material prepared in step S1 at 80 °C for 2 h, and then cure it at 120 °C for 2 h to obtain a cured material; Add methyltriethoxysilane into 100 times the weight of anhydrous ethanol, add one-half of the weight of the substrate of deionized water, and stir and react at 300 rpm for 30 min to obtain a hydrolysis solution;

[0042] S3: Spray the hydrolysis solution prepared in step S2 onto the surface of the cured material prepared in step S2. The spraying operation parameters are 0.1 MPa, a distance of 15 cm, and a speed of 20 cm / s. Let it stand for 5 min after each spraying, and spray 3 times in total. After spraying, dry it in vacuum at 60 °C for 2 h to obtain epoxy resin.

[0043] Example 2: An anti-aging electrical epoxy resin, whose composition includes the following raw materials by weight: 80 parts of epoxy resin, 5 parts of modified nano-silica, 3 parts of aminated graphene, 8 parts of polyurethane, 1 part of methyltriethoxysilane, 0.5 part of sodium dodecyl sulfate, 1 part of antioxidant and 1 part of ultraviolet absorber.

[0044] The specific preparation steps of the modified nano-silica are as follows:

[0045] A1: Add 10 g of nano-silica into 500 mL of anhydrous ethanol, and perform ultrasonic dispersion treatment at 200 W for 40 min to obtain a nano-silica dispersion; Add 10 g of γ-glycidoxypropyltrimethoxysilane into 200 mL of anhydrous ethanol, stir and mix evenly, then slowly drop 6 mL of deionized water and 0.5 mL of acetic acid, and stir and react at 300 rpm for 20 min to obtain a coupling agent solution;

[0046] A2: Slowly add 25 mL of the coupling agent solution prepared in step A1 into 500 mL of the nano-silica dispersion prepared in step A1. After stirring and reacting at room temperature at 500 rpm for 12 h, centrifuge, wash repeatedly with deionized water 5 times, and dry in vacuum at 80 °C for 18 h to obtain modified nano-silica;

[0047] The specific preparation steps of the aminated graphene are as follows:

[0048] B1: Add 10 g of graphite powder into a flask, slowly add 250 mL of concentrated sulfuric acid and 30 mL of concentrated phosphoric acid, control the temperature at 4 °C, stir to disperse evenly, raise the temperature to 10 °C, then slowly add 30 g of potassium permanganate. After the addition is complete, raise the temperature to 40 °C, stir and react for 18 h, then slowly add 1000 mL of deionized water for dilution, then add 40 mL of hydrogen peroxide, centrifuge, and wash repeatedly with deionized water and 1 M HCl solution for 3 times, and dry in vacuum at 60 °C for 24 h to obtain graphene oxide;

[0049] B2: Disperse 1500 mg of the graphene oxide prepared in step B1 in 300 mL of dimethyl sulfoxide, perform ultrasonic dispersion treatment at 150 W for 50 min to obtain a graphene oxide dispersion; control the temperature at 4 °C, slowly drop 15 mL of 3-aminopropyltriethoxysilane into the graphene oxide dispersion. After the dropping is complete, raise the temperature to 60 °C, continuously stir for 24 h, centrifuge, and wash repeatedly with deionized water and ethanol for 3 times, and dry in vacuum at 60 °C for 24 h to obtain amino-functionalized graphene;

[0050] The specific preparation steps of the anti-aging electrical epoxy resin are as follows:

[0051] S1: Add the modified nano-silica and amino-functionalized graphene into bisphenol A epoxy resin according to the weight ratio, stir at 1500 rpm for 50 min. After uniform dispersion, add sodium dodecyl sulfate, stir at 1200 rpm for 20 min, then add polyurethane, dilauryl thiodipropionate, and 2,2'-dihydroxy-4-methoxybenzophenone, stir at 800 rpm for 20 min to obtain a mixed raw material;

[0052] S2: Cure the mixed raw material prepared in step S1 at 80 °C for 2 h, and then cure at 120 °C for 2 h to obtain a cured material; add methyltriethoxysilane into 100 times the weight of anhydrous ethanol, add one-half of the weight of deionized water of the substrate, stir and react at 500 rpm for 20 min to obtain a hydrolysis solution;

[0053] S3: Spray the hydrolysis solution prepared in step S2 onto the surface of the cured material prepared in step S2. The spraying operation parameters are 0.3 MPa, a distance of 20 cm, a speed of 25 cm / s. After each spraying, let it stand for 10 min, spray 3 times in total. After the spraying is completed, dry in vacuum at 80 °C for 1.5 h to obtain an epoxy resin.

[0054] Example 3: An anti-aging electrical epoxy resin, whose composition includes the following raw materials by weight: 75 parts of epoxy resin, 4 parts of modified nano-silica, 2 parts of amino-functionalized graphene, 7 parts of polyurethane, 0.8 part of methyltriethoxysilane, 0.3 part of sodium dodecyl sulfate, 0.8 part of antioxidant, and 0.8 part of ultraviolet absorber.

[0055] The specific preparation steps of the modified nano-silica are as follows:

[0056] A1: Add 10 g of nano-silica into 450 mL of absolute ethanol, and perform ultrasonic dispersion treatment at 150 W for 30 min to obtain a nano-silica dispersion; add 10 g of γ-glycidoxypropyltrimethoxysilane into 180 mL of absolute ethanol, stir and mix evenly, then slowly add 5.5 mL of deionized water and 0.45 mL of acetic acid, and stir and react at 250 rpm for 10 min to obtain a coupling agent solution;

[0057] A2: Slowly add 20 mL of the coupling agent solution prepared in step A1 into 450 mL of the nano-silica dispersion prepared in step A1, stir and react at a rotation speed of 400 rpm at room temperature for 12 h, then centrifuge, wash repeatedly with deionized water for 5 times, and vacuum dry at 70 °C for 12 h to obtain the modified nano-silica;

[0058] The specific preparation steps of the amino-functionalized graphene are as follows:

[0059] B1: Add 10 g of graphite powder into a flask, slowly add 240 mL of concentrated sulfuric acid and 25 mL of concentrated phosphoric acid, control the temperature at 0 °C, stir and disperse evenly, raise the temperature to 10 °C, then slowly add 30 g of potassium permanganate. After the addition is completed, raise the temperature to 38 °C, stir and react for 12 h, then slowly add 900 mL of deionized water for dilution, then add 35 mL of hydrogen peroxide, centrifuge, wash repeatedly with deionized water and 1 M HCl solution for 3 times, and vacuum dry at 60 °C for 18 h to obtain graphene oxide;

[0060] B2: Disperse 1200 mg of the graphene oxide prepared in step B1 in 300 mL of dimethyl sulfoxide, perform ultrasonic dispersion treatment at 140 W for 30 min to obtain a graphene oxide dispersion; control the temperature at 0 °C, slowly add 14 mL of 3-aminopropyltriethoxysilane to the graphene oxide dispersion. After the addition is completed, raise the temperature to 60 °C, continuously stir for 18 h, centrifuge, wash repeatedly with deionized water and ethanol for 3 times, and vacuum dry at 60 °C for 18 h to obtain the amino-functionalized graphene;

[0061] The specific preparation steps of the anti-aging electrical epoxy resin are as follows:

[0062] S1: Add the modified nano-silica and the amino-functionalized graphene into bisphenol A epoxy resin according to the weight ratio, stir at 1400 rpm for 40 min. After dispersion, add sodium dodecyl sulfate, stir at 1000 rpm for 15 min, then add polyurethane, N-phenyl-α-naphthylamine and benzyl salicylate, and stir at 700 rpm for 15 min to obtain a mixed raw material;

[0063] S2: Cure the mixed raw materials prepared in step S1 at 80 °C for 2 h, and then cure at 120 °C for 2 h to obtain a cured material; Add methyltriethoxysilane to 100 times the weight of anhydrous ethanol, add deionized water with half the weight of the substrate, and stir and react at 400 rpm for 15 min to obtain a hydrolysis solution;

[0064] S3: Spray the hydrolysis solution prepared in step S2 onto the surface of the cured material prepared in step S2. The spraying operation parameters are 0.2 MPa, a distance of 18 cm, and a speed of 30 cm / s. After each spraying, let it stand for 8 min, and spray 3 times in total. After spraying, dry it in vacuum at 70 °C for 1 h to obtain epoxy resin.

[0065] Comparative Example 1: The operation of Comparative Example 1 is basically the same as that of Example 2, except that modified nano-silica is not added in Comparative Example 1.

[0066] Comparative Example 2: The operation of Comparative Example 2 is basically the same as that of Example 2, except that amino-functionalized graphene is not used in Comparative Example 2.

[0067] Comparative Example 3: The operation of Comparative Example 3 is basically the same as that of Example 2, except that methyltriethoxysilane hydrophobization treatment is not used in Comparative Example 3.

[0068] Comparative Example 4: The operation of Comparative Example 4 is basically the same as that of Example 2, except that nano-silica is used to replace modified nano-silica in Comparative Example 4.

[0069] Performance test:

[0070] Mechanical strength and insulation test: Use a universal material testing machine to test the tensile strength, flexural strength and compressive strength of the epoxy resin material samples prepared in Examples 1-3 and Comparative Examples 1-4. The results are shown in Table 1 below. Test the insulation resistivity of the epoxy resin material samples prepared in Examples 1-3 and Comparative Examples 1-4 according to GB / T 1409-2006. The results are shown in Table 1 below.

[0071] Table 1. Test results of mechanical strength and insulation of epoxy resin materials

[0072]

[0073] As can be seen from the results in Table 1, the epoxy resin material prepared by the present invention has excellent mechanical properties and insulation properties. At the same time, the addition of amino-functionalized graphene does not significantly affect the insulation properties of the epoxy resin material. From the results of Comparative Example 1 and Example 2, due to its high specific surface area and surface energy, nano-silica can significantly enhance the hardness, rigidity and anti-aging properties of the material. The lack of modified nano-silica leads to a significant decrease in the hardness and rigidity of the material. From the results of Comparative Example 2 and Example 2, the addition of amino-functionalized graphene can improve the toughness and impact resistance of the material. The non-use of amino-functionalized graphene may lead to an increase in the brittleness of the material, a decrease in the stress transfer efficiency, and a significant decrease in the mechanical strength. From the results of Comparative Example 4 and Example 2, the lack of silane-modified nano-silica may lead to poor dispersion of nano-silica and agglomeration, thus affecting the tensile strength and compressive strength of the matrix.

[0074] UV aging test: The epoxy resin material samples prepared in Example 2 and Comparative Examples 1-4 were subjected to UV lamp aging test. The test parameters were UVA-340 lamp tube to simulate ultraviolet light (0.35 W / m 2 ), temperature 60 °C, humidity 55%, light cycle was 12 h of light and 12 h of darkness, and the test was carried out for 500 h. The changes in the surface conditions of the samples were recorded at 96 h, 240 h and 500 h. The results are shown in Table 2 below, as well as the percentage change in tensile strength (tensile strength change = (tensile strength before test - tensile strength after test) / tensile strength before test × 100%), and the results are as Figure 1 shown.

[0075] Table 2. Results of changes in surface conditions of epoxy resin materials in UV aging test

[0076]

[0077] From Table 2 and Figure 1It can be seen from the results that the epoxy resin material prepared by the present invention has excellent anti-aging performance and can be used effectively for a long time. From the results of Comparative Example 1 and Example 2, it can be seen that due to the absence of modified nano-silica and the lack of the effect of fillers, it is impossible to effectively enhance the hardness and rigidity of the material. At the same time, the absence of nano-silica makes the material more likely to have molecular chain breakage under ultraviolet irradiation, resulting in obvious acceleration of aging and decline in mechanical properties. From the results of Comparative Example 2 and Example 2, it can be seen that the high thermal conductivity of graphene itself helps to disperse heat, reduce stress concentration in local high-temperature areas, and thus slow down the aging of the material caused by temperature changes or ultraviolet irradiation. However, for the material lacking amino-functionalized graphene, an effective thermal conduction network cannot be formed, which may lead to an accelerated aging process in the temperature concentration area, resulting in obvious cracking phenomena and a significant decline in the mechanical properties of the material. From the results of Comparative Example 3 and Example 2, it can be seen that due to the lack of hydrophobic treatment, this may lead to the accumulation of moisture on the material surface. The presence of moisture will accelerate the degradation reaction induced by ultraviolet rays, resulting in obvious cracking and yellowing on the surface and a significant decline in the mechanical properties of the material. From the results of Comparative Example 4 and Example 2, it can be seen that the surface of nano-silica lacks organic functional groups and has strong hydrophilicity, which is easy to agglomerate in epoxy resin. This may lead to uneven dispersion, thus affecting its strengthening effect and resulting in a significant decline in the anti-aging performance of the material under ultraviolet irradiation.

[0078] Thermal performance test: The epoxy resin materials prepared in Example 2 and Comparative Examples 1-4 were subjected to a heat distortion temperature test. Under 0.45 MPa and 1.8 MPa, the deformation temperatures of the above samples were tested at a heating rate of 120 °C / h. The control group was bisphenol A type epoxy resin, and the results are as Figure 2 shown.

[0079] From Figure 2It can be seen from the results that the epoxy resin material prepared by the present invention has an extremely high heat distortion temperature through the synergistic effect of various substances. It can be seen from the results of Comparative Example 1 and Example 2 that due to the absence of modified nano-silica, there may be filler aggregation in the epoxy resin, which will lead to poor dispersibility and compatibility of the material, and its thermal properties may be poor, thus resulting in a lower heat distortion temperature. It can be seen from the results of Comparative Example 2 and Example 2 that the absence of amino-functionalized graphene may reduce the thermal conductivity and interfacial bonding strength of the material, affect the transfer of thermal stress, and lead to an obvious influence on the heat distortion temperature. It can be seen from the results of Comparative Example 3 and Example 2 that the hydrophobic treatment indirectly improves the thermal properties by improving the water resistance and corrosion resistance of the material surface, preventing the erosion of the material by water and corrosive media, and the lack of this treatment may cause the material to be damaged in a humid environment, to a certain extent affecting its thermal stability and distortion temperature. It can be seen from the results of Comparative Example 4 and Example 2 that unmodified nano-silica usually has poor dispersibility in epoxy resin, and its hydrophilicity will lead to weak bonding force between the filler and the resin matrix, which may result in a lower heat distortion temperature.

[0080] Corrosion resistance test: Continuously spray the epoxy resin material samples prepared in Example 2 and Comparative Examples 1 to 4 with 5% NaCl solution at 35 °C for 16 h, then stop for 8 h, and test for 96 h. The percentage change in tensile strength at 24 h, 48 h, and 96 h was measured respectively (tensile strength change = (tensile strength before test - tensile strength after test) / tensile strength before test × 100%). The results are as Figure 3 shown.

[0081] From Figure 3It can be seen from the results that the epoxy resin material prepared by the present invention has excellent corrosion resistance; from the results of Comparative Example 1 and Example 2, it can be seen that due to the absence of modified nano-silica, the lack of effective interfacial bonding force and filler reinforcement effect may lead to lower hardness and rigidity of the material, which in turn causes deformation and aging of the material in a corrosive environment, resulting in a significant impact on the tensile strength; from the results of Comparative Example 2 and Example 2, it can be seen that the lack of amino-functionalized graphene will lead to a reduction in the penetration resistance of corrosive media. The absence of graphene results in the material being unable to effectively dissipate heat through the thermal conduction network and also lacking physical barrier protection, resulting in poor corrosion resistance of the material and an obvious impact on the tensile strength; from the results of Comparative Example 3 and Example 2, it can be seen that the hydrophobic coating can effectively prevent the intrusion of moisture, and enhances the weather resistance and moisture resistance of the material through physical adsorption and hydrogen bonding. The lack of a hydrophobic coating makes the material more vulnerable to the external environment, especially in a humid environment, resulting in an accelerated corrosion rate of the material, which in turn affects the tensile strength; from the results of Comparative Example 4 and Example 2, it can be seen that since the surface of the unmodified nano-silica does not have epoxy groups and cannot undergo an effective chemical reaction with the epoxy resin matrix, the interfacial bonding force is weak, which in turn affects the tensile strength of the material in a corrosive environment.

[0082] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An anti-aging electrical epoxy resin, characterized in that: The composition includes the following raw materials in parts by weight: 70-80 parts of epoxy resin, 3-5 parts of modified nano silicon dioxide, 1-3 parts of amino graphene, 5-8 parts of polyurethane, 0.5-1 parts of methyl triethoxy silane, 0.1-0.5 parts of sodium dodecyl sulfate, 0.5-1 parts of antioxidant and 0.5-1 parts of ultraviolet absorber; The specific preparation steps of the modified nano silicon dioxide are as follows: A1: Add nano-silica to anhydrous ethanol, perform ultrasonic dispersion treatment, and obtain a nano-silica dispersion; add γ-glycidyloxypropyltrimethoxysilane to anhydrous ethanol, stir and mix evenly, then slowly drop deionized water and acetic acid, stir and react, and obtain a coupling agent solution; A2: slowly adding the coupling agent solution prepared in step A1 to the nano-silica dispersion prepared in step A1, stirring the mixture to react at room temperature, centrifuging, repeatedly washing with deionized water, and vacuum drying to obtain modified nano-silica; The specific preparation steps of the amino graphene are as follows: B1: Add graphite powder to a flask, slowly add concentrated sulfuric acid and concentrated phosphoric acid, control the temperature at 0-5°C, stir and disperse evenly, raise the temperature to 10°C, and then slowly add potassium permanganate. After the addition is complete, raise the temperature, stir to react, slowly add deionized water to dilute, then add hydrogen peroxide, centrifuge, repeatedly wash with deionized water and 1M HCl solution, and vacuum dry to obtain graphene oxide; B2: dispersing the graphene oxide prepared in step B1 in dimethyl sulfoxide, and performing ultrasonic dispersion treatment to obtain a graphene oxide dispersion; controlling the temperature at 0-5°C, slowly dropping 3-aminopropyltriethoxysilane into the graphene oxide dispersion, and after the dropping is completed, raising the temperature to 60°C, continuously stirring, centrifuging, repeatedly washing with deionized water and ethanol, and vacuum drying to obtain amino graphene; The method for preparing the anti-aging electrical epoxy resin is characterized in that the specific preparation steps are as follows: S1: adding modified nano-silica and amino graphene to epoxy resin in proportion by weight, stirring, and after uniform dispersion, adding sodium dodecyl sulfate, stirring, and then adding polyurethane, antioxidant and ultraviolet absorber, stirring to obtain a mixed raw material; S2: curing the mixed raw material prepared in step S1 at 80° C. for 2 h, and then curing at 120° C. for 2 h to obtain a cured material; adding methyltriethoxysilane to anhydrous ethanol, adding deionized water in an amount of one-half the weight of the substrate, stirring to react, and obtaining a hydrolysis solution; S3: spraying the hydrolysis solution prepared in step S2 onto the surface of the curing material prepared in step S2, and after spraying, vacuum drying to obtain epoxy resin; In step S3, the spraying operation parameters are 0.1-0.3 MPa, a distance of 15-20 cm, a speed of 20-30 cm / s, and a standing time of 5-10 minutes after each spraying, for a total of 3 sprayings.

2. An anti-aging electrical epoxy resin according to claim 1, characterized in that: The antioxidant is any one of 2,6-di-tert-butyl-p-cresol, ascorbic acid, N-phenyl-α-naphthylamine and dilauryl thiodipropionate.

3. An anti-aging electrical epoxy resin according to claim 2, characterized in that: The ultraviolet absorber is any one of 2-hydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, benzyl salicylate and phenyl salicylic acid.

4. An anti-aging electrical epoxy resin according to claim 3, characterized in that: In step A1, the ratio of the amount of the nano-silica to anhydrous ethanol is 1 g: 40-50 mL; the ratio of the amount of γ-glycidyloxypropyltrimethoxysilane, anhydrous ethanol, deionized water and acetic acid is 1 g: 15-20 mL: 0.5-0.6 mL: 0.04-0.05 mL.

5. The anti-aging electrical epoxy resin according to claim 4, characterized in that: In step A2, the volume ratio of the coupling agent solution to the nano-silicon dioxide dispersion is 0.02-0.03:

1.

6. The anti-aging electrical epoxy resin according to claim 5, characterized in that: In step B1, the ratio of the amount of graphite powder, concentrated sulfuric acid and concentrated phosphoric acid is 1g:20-25mL:2-3mL; the ratio of the amount of potassium permanganate, deionized water, hydrogen peroxide and graphite powder is 3g:80-100mL:3-4mL:1g.

7. An anti-aging electrical epoxy resin according to claim 6, characterized in that: In step B2, the ratio of the amount of graphene oxide, dimethyl sulfoxide and 3-aminopropyltriethoxysilane is 3-5 mg:1 mL:0.04-0.05 mL.

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