Epoxy glass fiber insulating material as well as preparation process and application thereof

Abstract

The invention belongs to the technical field of insulating materials, and particularly relates to an epoxy glass fiber insulating material as well as a preparation process and application thereof. According to the epoxy glass fiber insulating material, gallic acid and epoxy chloropropane are used for modifying an epoxy resin matrix, fluorinated zinc oxide is used for improving the dispersity of a zinc oxide filler, and an epoxy silane coupling agent is combined with polydopamine modified glass fiber to improve the interface bonding property with the matrix; finally, the mechanical property, the insulating property and the thermal conductivity of the epoxy glass fiber insulating material are comprehensively improved through the cooperation of structure optimization, filler dispersion strengthening and interface bonding strengthening. The prepared epoxy glass fiber insulating material is excellent in comprehensive performance and suitable for components such as high-voltage switch insulating pull rods and the like.

Description

Technical Field

[0001] The present application belongs to the technical field of insulating materials, and in particular relates to an epoxy glass fiber insulating material, a preparation process and an application thereof. Background Art

[0002] The operational reliability of power equipment is a key factor in ensuring the stable transmission of electric energy. Epoxy resins and their composite materials are widely used in high-voltage power transmission and transformation insulation equipment due to their high-temperature resistance, corrosion resistance, light weight, high insulation strength, and excellent mechanical properties. These include composite insulators, UHVDC converter bushings, high-voltage switches, and dry-type transformers / reactors, among other key equipment in the high-voltage transmission sector. However, power equipment often experiences failures during long-term operation, increasing operational and maintenance costs and reducing safety and reliability. Aging and damage to equipment insulation is a major cause of power failures. Examples include internal insulation aging due to localized heat accumulation, ultimately leading to insulation breakdown; aging and breakdown of main insulation at cable terminals; and mechanical insulation failure under high mechanical stress. Effectively improving the performance of insulation materials has become a key issue hindering the further development of power technology.

[0003] Traditional epoxy resin polymers are brittle, resulting in poor impact resistance and prone to cracking. Under temperature fluctuations or mechanical stress, these cracks can propagate and ultimately affect the material's insulation performance and service life. Under high-power operating conditions, internal heat cannot be effectively dissipated, leading to a gradual decline in mechanical strength and insulation performance, which in turn affects stable operation. Furthermore, despite epoxy resin's excellent insulation properties, high voltage levels and large device sizes lead to an increase in internal insulation defects during the preparation process, making the insulation properties of traditional epoxy resins increasingly unable to meet the insulation requirements of current ultra-high voltage (UHV) power equipment. While glass fiber reinforcement effectively improves the toughness of epoxy-glass fiber insulation, the polymer matrix remains a weak point in the composite material. Furthermore, because the insulation material incorporates numerous glass fiber-epoxy resin interfaces, glass fiber, as an inorganic material, exhibits poor interfacial compatibility with epoxy resin. Furthermore, the smooth surface of the glass fiber prevents efficient stress transfer at the interface, impacting the overall performance improvement efficiency of the insulation material and making the interface susceptible to defects under external forces. With the rapid development of high-voltage power transmission technology, the performance of traditional epoxy glass fiber insulation materials has also become a key factor restricting the improvement of the reliability of power transmission and transformation equipment.

[0004] Therefore, the development of epoxy glass fiber insulation materials with higher thermal conductivity, insulation and mechanical properties is an important goal that needs to be achieved urgently. Summary of the Invention

[0005] In view of the above-mentioned shortcomings of the prior art, the object of the present invention is to provide an epoxy glass fiber insulation material, a preparation process and its application, so as to solve the problems of insufficient thermal conductivity, insulation and mechanical properties of epoxy glass fiber insulation materials in the prior art.

[0006] To achieve the above-mentioned purpose and other related purposes, the present invention is achieved through the following technical solutions.

[0007] The first aspect of the present invention is to provide an epoxy glass fiber insulation material, comprising the following raw materials in parts by weight: 30-60 parts of modified epoxy resin, 4.5-6 parts of fluorinated zinc oxide, 25-50 parts of curing agent, 2-5 parts of accelerator, and 20-45 parts of modified glass fiber.

[0008] In some embodiments of the present invention, the modified epoxy resin is prepared by the following steps: 1) gallic acid and dipropanolamine are reacted in p-toluenesulfonic acid under nitrogen to obtain gallic acid dipropanolamine amide; 2) bisphenol A, epichlorohydrin and gallic acid dipropanolamine amide are mixed and condensed, and then an alkaline solution is added dropwise to neutralize to obtain a modified epoxy resin.

[0009] In some embodiments of the present invention, the molar amount of dipropanolamine in step 1) is 1.02-1.2 times that of gallic acid.

[0010] In some embodiments of the present invention, the gallic acid dipropanolamine amide in step 2) is 5-10% of the mass of bisphenol A; the molar amount of epichlorohydrin in step 2) is at least 3 times the total molar amount of hydroxyl groups in bisphenol A and gallic acid dipropanolamine amide.

[0011] In some embodiments of the present invention, the alkaline solution in step 2) is a sodium hydroxide solution. - The molar amount is equal to the total molar amount of hydroxyl groups in bisphenol A and gallic acid dipropanolamine amide.

[0012] In some embodiments of the present invention, the preparation method of the modified glass fiber is as follows: a. After removing impurities from the glass fiber, mixing it with water to form a suspension, then adding tris base and dopamine, adjusting the pH value to 8-10, stirring the reaction to form a polydopamine layer on the surface of the glass fiber, centrifuging, filtering, washing, and drying to obtain PDA@GF; b. ultrasonically reacting the epoxy silane coupling agent hydrolyzate with PDA@GF, centrifuging, filtering, washing, and drying to obtain the modified glass fiber.

[0013] In some embodiments of the present invention, the ratio of the glass fiber, tris base and dopamine used in step a is 40 g: (1.2-1.5) g: (0.4-0.6) g.

[0014] In some embodiments of the present invention, the epoxy silane coupling agent hydrolyzate in step b is prepared by the following method: the epoxy silane coupling agent is mixed with an ethanol aqueous solution having an ethanol content of 90 wt% at a solid-liquid ratio of 1 g: 20 mL, and then the pH is adjusted to 3.5-5, and stirred at 30-50 ° C for 1-2 hours; the epoxy silane coupling agent is 10-15 wt% of the glass fiber.

[0015] In some embodiments of the present invention, the epoxy silane coupling agent is one of γ-glycidyloxypropyltrimethoxysilane, γ-glycidyloxypropyltriethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and β-(3,4-epoxycyclohexyl)ethyltriethoxysilane.

[0016] The second aspect of the present invention is to provide a preparation process for the above-mentioned epoxy glass fiber insulation material, comprising the following steps: S1, preheating the modified epoxy resin at 60-70°C, adding part of the fluorinated zinc oxide, vacuum degassing and dispersing to obtain a first component; preheating the curing agent at 60-70°C, adding the remaining part of the fluorinated zinc oxide, vacuum degassing and dispersing to obtain a second component; S2, mixing the first component and the second component at 70-80°C, then adding an accelerator, stirring evenly, then maintaining a constant temperature and performing vacuum degassing to obtain a glue solution; S3, pouring the glue solution into a dipping tank, passing the modified glass fiber through the dipping tank at 80-85°C, and winding it by a wet winding process; S4, after winding, placing it in a curing furnace and curing it according to the prescribed curing procedure of 100°C / 2h+120°C / 20min until it is completely gelled to obtain the epoxy glass fiber insulation material.

[0017] A third aspect of the present invention provides an application of the above-mentioned epoxy glass fiber insulation material for insulating pull rods.

[0018] As described above, the epoxy glass fiber insulation material, preparation process and application of the present invention have the following beneficial effects: 1. This application uses gallic acid and epichlorohydrin to modify the epoxy resin matrix, uses fluorinated zinc oxide to improve the dispersibility of zinc oxide filler, and uses epoxy silane coupling agent combined with polydopamine to modify glass fiber to improve the interface bonding with the matrix. Ultimately, through the synergy of structural optimization-filler dispersion enhancement-interface bonding enhancement, the mechanical properties, insulation properties and thermal conductivity of epoxy glass fiber insulation materials are comprehensively improved.

[0019] 2. The epoxy glass fiber insulation material prepared in this application has excellent comprehensive performance and is suitable for insulating pull rods. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1Shown are SEM images of the fracture surface of the epoxy glass fiber insulation material of the present invention, wherein (a) is the glass fiber before modification, (b) is the modified glass fiber of Comparative Example 2, and (c) is the modified glass fiber of Example 3. DETAILED DESCRIPTION

[0021] This application addresses the problems of insufficient mechanical properties, insulation properties and thermal conductivity of existing epoxy glass fiber insulation materials, and through a large number of experimental studies, significantly improves the comprehensive performance of epoxy glass fiber insulation materials through multi-dimensional synergy.

[0022] First, the polyhydroxyl groups of gallic acid are used as "branching points" to promote the formation of more side chains in the epoxy resin molecular chain. Epichlorohydrin is used as a "cross-linking bridge" to further connect the side chains with the main chain, ultimately significantly improving the branching degree and cross-linking density of the epoxy resin, making the matrix structure denser, fundamentally improving the mechanical strength such as tensile and bending, and reducing the pores and free volume inside the matrix.

[0023] Then, zinc oxide is modified by fluorination to reduce its surface energy, make it hydrophobic, reduce water adsorption, and reduce agglomeration, thereby improving the compatibility of zinc oxide with the epoxy resin matrix. The "pinning effect" can inhibit the expansion of matrix cracks and further improve its toughness. In addition, the high electronegativity of fluorine can enhance the dielectric properties of epoxy glass fiber insulation materials, inhibit the semiconductor properties of zinc oxide, and increase the volume resistivity; through improved dispersion and interface bonding, the particle-resin thermal resistance can be reduced.

[0024] Finally, polydopamine is used to form a uniform coating on the surface of the glass fiber through adhesion, reacting with the epoxy silane coupling agent. The epoxy group on the other end can react with the epoxy group / hydroxyl group of the epoxy resin to form a strong interface bond of "fiber-PDA-coupling agent-resin", effectively transferring stress, avoiding interface peeling, and solving the problem of sudden strength drop caused by "debonding" between fiber and resin in traditional materials. In traditional materials, the interface is prone to charge accumulation, leading to breakdown. However, the strong interface bond between the modified glass fiber and the matrix in this application avoids interface gaps and can effectively increase the breakdown field strength; the highly cross-linked matrix and strong interface bond prevent moisture from penetrating the interface, enhancing its environmental stability; by strengthening the interface bond and forming a three-dimensional thermally conductive skeleton, the fiber-resin thermal resistance is reduced.

[0025] Ultimately, through the triple synergy of "matrix densification, strong interface bonding, and filler functionalization," a "1+1+1>3" effect was achieved. Highly cross-linked modified epoxy resin provides a "robust skeleton" for the epoxy glass fiber insulation material, while fluorinated zinc oxide serves as a "functional filler," simultaneously enhancing both mechanical and insulating properties. The glass fiber, coated with polydopamine and epoxy silane coupling agents, acts as a "reinforcement bridge," tightly connecting the skeleton and filler. Ultimately, the epoxy glass fiber insulation material boasts comprehensive improvements in mechanical strength, insulation reliability, and environmental adaptability.

[0026] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0028] Where “including,” “having,” and “comprising” are used herein, it is intended to cover a non-exclusive inclusion, and another component may also be added unless a clear limiting term such as “only,” “consisting of,” etc. is used.

[0029] The words "preferably", "more preferably", "preferably", "better", etc. in this application refer to embodiments of the present application that may provide certain beneficial effects in certain circumstances. However, other embodiments may also be preferred under the same circumstances or other circumstances. In addition, the statement of one or more preferred embodiments does not imply that other embodiments are not available, nor is it intended to exclude other embodiments from the scope of this application. That is, in this application, "preferably", "more preferably", "preferably", "better", etc. are merely descriptions of implementation methods or examples with better effects, but do not constitute a limitation on the scope of protection of this application.

[0030] In the present application, “further”, “further”, “particularly”, etc. are used for descriptive purposes to indicate differences in content but should not be understood as limiting the scope of protection of the present application.

[0031] In this application, "at least one" means more than one, such as one, two, or more than two. "Multiple" or "several" means at least two, such as two, three, etc., and "multi-layer" means at least two layers, such as two, three, etc., unless otherwise specifically defined. In the description of this application, "several" means at least one, such as one, two, etc., unless otherwise specifically defined.

[0032] When a numerical range is disclosed herein, the range is considered continuous and includes the minimum and maximum values ​​of the range, as well as every value between such minimum and maximum values. Further, when a range refers to an integer, every integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe a feature or characteristic, the ranges can be combined. In other words, unless otherwise indicated, all ranges disclosed herein are understood to include any and all subranges subsumed therein.

[0033] Unless otherwise specified, all steps of the present application may be performed sequentially or randomly. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may further include step (c), indicating that step (c) may be added to the method in any order, for example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc. Unless otherwise mentioned, terms in the singular may include plural forms and are not to be understood as being one in number.

[0034] The present application is further described below by way of examples, but the scope of the present application is not limited thereby.

[0035] When the embodiments provide numerical ranges, it should be understood that, unless otherwise specified herein, both endpoints of each numerical range and any numerical value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as those generally understood by those skilled in the art. Where specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or the conditions recommended by the manufacturer. Where all reagents or instruments are not specified by the manufacturer, they are conventional products that can be purchased commercially. In addition to the specific methods, equipment, and materials used in the embodiments, according to the prior art mastery and the record of the present application by those skilled in the art, any methods, equipment, and materials of the prior art similar or equivalent to the methods, equipment, and materials described in the embodiments of the present application can also be used to realize the present application.

[0036] Example 1 An epoxy glass fiber insulation material is prepared from the following raw materials in parts by weight: 3 kg of modified epoxy resin, 0.45 kg of fluorinated zinc oxide, 2.5 kg of a curing agent, 0.2 kg of an accelerator, and 2 kg of modified glass fiber.

[0037] In this embodiment, the curing agent is hexahydrophthalic anhydride.

[0038] In this embodiment, the accelerator is 2,4,6-tris(dimethylaminomethyl)phenol.

[0039] In this embodiment, the fluorinated zinc oxide is prepared by fluorinating and calcining nano zinc oxide by discharging with a plasma high-voltage power supply in the presence of argon and carbon tetrafluoride gases. The particle size of the fluorinated zinc oxide is 30-60 nm.

[0040] The modified epoxy resin in this embodiment is prepared by the following steps: Under nitrogen, 1 mol of gallic acid was mixed with 1.02 mol of dipropanolamine, 0.5 mol of p-toluenesulfonic acid was added, and then 5 mL of DMF (N,N-dimethylformamide) was added. The mixture was heated to 110°C and stirred until the reaction no longer proceeded. After purification, gallic acid dipropanolamine amide was obtained. Mix 100 g of bisphenol A, 267 g of epichlorohydrin and 5 g of dipropanolamine gallate, stir and react at 110 ° C for 4 h, then slowly add 193 mL of 5 mol / L sodium hydroxide solution, continue stirring until the reaction no longer proceeds, separate the liquids, collect the organic phase, and evaporate under reduced pressure at 70 ° C to obtain a modified epoxy resin.

[0041] The preparation method of the modified glass fiber in this embodiment is: a. 40 g of glass fiber was immersed in acetone as solvent and ultrasonically treated for 15 min. Then, it was immersed in ethanol as solvent and ultrasonically treated for 15 min. The fiber was rinsed with deionized water, dried, and mixed with 250 mL of water to form a suspension. Then, 1.2 g of tris base and 0.4 g of dopamine were added. The pH value was adjusted to 8. The suspension was stirred to form a polydopamine layer on the surface of the glass fiber. The suspension was centrifuged, filtered, washed, and dried to obtain PDA@GF. b. The epoxy silane coupling agent hydrolyzate was ultrasonically reacted with PDA@GF, centrifuged, filtered, washed, and dried to obtain modified glass fiber.

[0042] In this embodiment, the epoxy silane coupling agent hydrolyzate was prepared by the following method: 4 g of epoxy silane coupling agent γ-glycidyloxypropyltrimethoxysilane was mixed with an ethanol aqueous solution having an ethanol content of 90 wt % at a solid-liquid ratio of 1 g:20 mL, and then the pH was adjusted to 3.5 and stirred at 30° C. for 1 h to obtain the obtained solution.

[0043] Example 2 An epoxy glass fiber insulation material is prepared from the following raw materials in parts by weight: 4.5 kg of modified epoxy resin, 0.55 kg of fluorinated zinc oxide, 3.8 kg of curing agent, 0.4 kg of accelerator, and 0.3 kg of modified glass fiber.

[0044] In this embodiment, the curing agent is hexahydrophthalic anhydride.

[0045] In this embodiment, the accelerator is 2,4,6-tris(dimethylaminomethyl)phenol.

[0046] In this embodiment, the fluorinated zinc oxide is prepared by fluorinating and calcining nano zinc oxide by discharging with a plasma high-voltage power supply in the presence of argon and carbon tetrafluoride gases. The particle size of the fluorinated zinc oxide is 30-60 nm.

[0047] The modified epoxy resin in this embodiment is prepared by the following steps: Under nitrogen, 1 mol of gallic acid and 1.1 mol of dipropanolamine were mixed, 0.5 mol of p-toluenesulfonic acid was added, and then 5 mL of DMF (N,N-dimethylformamide) was added. The temperature was raised to 110°C and stirred until the reaction no longer proceeded. After purification, gallic acid dipropanolamine amide was obtained. Mix 100 g of bisphenol A, 282 g of epichlorohydrin and 8 g of dipropanolamine gallate, stir and react at 110 ° C for 4 h, then slowly add 203 mL of 5 mol / L sodium hydroxide solution, continue stirring until the reaction no longer proceeds, separate the liquids, collect the organic phase, and evaporate under reduced pressure at 70 ° C to obtain a modified epoxy resin.

[0048] The preparation method of the modified glass fiber in this embodiment is as follows: a. 40 g of glass fiber was immersed in acetone as solvent and ultrasonically treated for 15 min. Then, it was immersed in ethanol as solvent and ultrasonically treated for 15 min. The fiber was rinsed with deionized water, dried, and mixed with 280 mL of water to form a suspension. Then, 1.4 g of tris base and 0.5 g of dopamine were added. The pH value was adjusted to 9. The suspension was stirred to form a polydopamine layer on the surface of the glass fiber. The suspension was centrifuged, filtered, washed, and dried to obtain PDA@GF. b. The epoxy silane coupling agent hydrolyzate was ultrasonically reacted with PDA@GF, centrifuged, filtered, washed, and dried to obtain modified glass fiber.

[0049] In this embodiment, the epoxy silane coupling agent hydrolyzate was prepared by the following method: 4.8 g of epoxy silane coupling agent γ-glycidyloxypropyltrimethoxysilane was mixed with an ethanol aqueous solution having an ethanol content of 90 wt% at a solid-liquid ratio of 1 g:20 mL, and then the pH was adjusted to 4 and stirred at 40° C. for 1.5 h to obtain the obtained solution.

[0050] Example 3 An epoxy glass fiber insulation material is prepared from the following raw materials in parts by weight: 6 kg of modified epoxy resin, 0.6 kg of fluorinated zinc oxide, 5 kg of a curing agent, 0.5 kg of an accelerator, and 4.5 kg of modified glass fiber.

[0051] In this embodiment, the curing agent is hexahydrophthalic anhydride.

[0052] In this embodiment, the accelerator is 2,4,6-tris(dimethylaminomethyl)phenol.

[0053] In this embodiment, the fluorinated zinc oxide is prepared by fluorinating and calcining nano zinc oxide by discharging with a plasma high-voltage power supply in the presence of argon and carbon tetrafluoride gases. The particle size of the fluorinated zinc oxide is 30-60 nm.

[0054] The modified epoxy resin in this embodiment is prepared by the following steps: Under nitrogen, 1 mol of gallic acid was mixed with 1.2 mol of dipropanolamine, 0.5 mol of p-toluenesulfonic acid was added, and then 5 mL of DMF (N,N-dimethylformamide) was added. The mixture was heated to 110°C and stirred until the reaction no longer proceeded. After purification, gallic acid dipropanolamine amide was obtained. Mix 100 g of bisphenol A, 291 g of epichlorohydrin and 10 g of dipropanolamine gallate, stir and react at 110 ° C for 4 h, then slowly add 210 mL of 5 mol / L sodium hydroxide solution, continue stirring until the reaction no longer proceeds, separate the liquids, collect the organic phase, and evaporate under reduced pressure at 70 ° C to obtain a modified epoxy resin.

[0055] The preparation method of the modified glass fiber in this embodiment is as follows: a. 40 g of glass fiber was immersed in acetone as a solvent and ultrasonically treated for 15 min. Then, it was immersed in ethanol as a solvent and ultrasonically treated for 15 min. The fiber was rinsed with deionized water, dried, and mixed with 300 mL of water to form a suspension. Then, 1.5 g of tris base and 0.6 g of dopamine were added. The pH value was adjusted to 10. The suspension was stirred to form a polydopamine layer on the surface of the glass fiber. The suspension was centrifuged, filtered, washed, and dried to obtain PDA@GF. b. The epoxy silane coupling agent hydrolyzate was ultrasonically reacted with PDA@GF, centrifuged, filtered, washed, and dried to obtain modified glass fiber.

[0056] In this embodiment, the epoxy silane coupling agent hydrolyzate is prepared by the following method: 6 g of epoxy silane coupling agent γ-glycidyloxypropyltrimethoxysilane is mixed with an ethanol aqueous solution having an ethanol content of 90 wt% at a solid-liquid ratio of 1 g:20 mL, and then the pH is adjusted to 5 and stirred at 50° C. for 2 h to obtain the obtained solution.

[0057] A preparation process of epoxy glass fiber insulation material comprises the following steps: S1, preheating the modified epoxy resin at 60-70°C, adding a portion of zinc oxide fluoride (two-thirds of the mass of the zinc oxide fluoride), vacuum degassing and dispersing to obtain a first component; preheating the curing agent at 60-70°C, adding the remaining portion of zinc oxide fluoride, and vacuum degassing and dispersing to obtain a second component; S2, mixing the first component and the second component at 70-80°C, then adding the accelerator, stirring evenly, and then maintaining a constant temperature and performing vacuum degassing to obtain a glue solution; S3, pouring the glue solution into the dipping tank, the modified glass fiber passes through the dipping tank at 80-85°C, and is wound by a wet winding process; S4. After winding, place the fiberglass into a curing oven and cure according to the prescribed curing procedure at 100-110°C / 2h+120-130°C / 20min until it is completely gelled to obtain epoxy glass fiber insulation material.

[0058] Comparative Example 1 The same as Example 3, except that zinc oxide of the same mass is used instead of zinc oxide fluoride.

[0059] Comparative Example 2 The same as Example 3, except that the modified glass fiber is prepared by: 40g of glass fiber is immersed in acetone as a solvent and ultrasonically treated for 15 minutes, then immersed in ethanol as a solvent and ultrasonically treated for 15 minutes, rinsed with deionized water, dried, and then ultrasonically reacted with an epoxy silane coupling agent hydrolyzate, centrifuged, filtered, washed, and dried to obtain the modified glass fiber. The epoxy silane coupling agent hydrolyzate is prepared by the following method: In this example, the epoxy silane coupling agent hydrolyzate is prepared by the following method: 6g of epoxy silane coupling agent γ-glycidyloxypropyltrimethoxysilane is mixed with an ethanol aqueous solution having an ethanol content of 90wt% at a solid-liquid ratio of 1g:20mL, then the pH is adjusted to 5 and stirred at 50°C for 2h to obtain the modified glass fiber.

[0060] Comparative Example 3 The same as Example 3, except that epoxy resin E-51 of the same mass is used instead of the modified epoxy resin.

[0061] Performance testing: 1. The epoxy glass fiber insulation materials prepared in Examples 1-3 and Comparative Examples 1-3 were subjected to the following performance tests (mechanical properties were tested in accordance with the GB / T1447-2005 test method; dielectric constant and dielectric loss factor were tested in accordance with the GB / T1409-2006 test method; volume resistivity was tested in accordance with the GB / T1410-2006 test method; thermal conductivity was tested in accordance with the GB / T29313-2012 test method). The test results are shown in Table 1: Table 1 Performance test results As can be seen from Table 1, the epoxy glass fiber insulation materials prepared in Examples 1 to 3 of the present application have excellent mechanical properties, good insulation properties, and better thermal conductivity.

[0062] 2. Epoxy glass fiber insulation materials were prepared using glass fiber raw materials and the modified glass fiber of Comparative Example 2 instead of the modified glass fiber of Example 3. The epoxy glass fiber insulation materials were then bent and broken. The surface morphology of the fractured surface of the epoxy glass fiber insulation materials was observed using a scanning electron microscope. Figure 1 shown.

[0063] from Figure 1 As can be seen from (a), before the glass fiber is modified, the separation of the modified epoxy resin matrix and the glass fiber can be clearly observed on the fracture surface of the epoxy glass fiber insulation material, indicating that the compatibility between the glass fiber and the modified epoxy resin matrix is ​​poor; Figure 1 As can be seen from (b), the fracture surface of the epoxy glass fiber insulation material prepared by using the glass fiber directly modified by the epoxy silane coupling agent has good interface bonding between the modified epoxy resin matrix and the modified fiber in some places, but the glass fibers are still obviously separated and cannot be well bonded; Figure 1 As can be seen in (c), the epoxy glass fiber insulation material prepared using glass fibers modified with epoxy silane coupling agents and polydopamine exhibits a tight bond between the modified glass fibers and the modified epoxy resin matrix at the fracture surface. This demonstrates that the use of epoxy silane coupling agents and polydopamine to synergistically modify glass fibers in this application significantly improves the interfacial bonding between the glass fiber and the epoxy resin matrix, ensuring effective stress transfer and enhancing mechanical properties.

[0064] Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. An epoxy glass fiber insulation material, characterized by: The invention comprises the following raw materials in parts by weight: 30-60 parts of modified epoxy resin, 4.5-6 parts of fluorinated zinc oxide, 25-50 parts of curing agent, 2-5 parts of accelerator and 20-45 parts of modified glass fiber.

2. The epoxy glass fiber insulation material according to claim 1, characterized in that: The modified epoxy resin is prepared by the following steps: 1) gallic acid and dipropanolamine are subjected to amidation reaction in p-toluenesulfonic acid under nitrogen to obtain gallic acid dipropanolamine amide; 2) bisphenol A, epichlorohydrin and gallic acid dipropanolamine amide are mixed and polycondensed, and then an alkaline solution is added dropwise for neutralization to obtain the modified epoxy resin.

3. The epoxy glass fiber insulation material according to claim 2, characterized in that: In step 1), the molar amount of the dipropanolamine is 1.02-1.2 times that of gallic acid.

4. The epoxy glass fiber insulation material according to claim 2, characterized in that: In step 2), the gallic acid dipropanolamine amide is 5-10% of the mass of bisphenol A; And / or, in step 2), the molar amount of epichlorohydrin is at least 3 times the total molar amount of hydroxyl groups in bisphenol A and gallic acid dipropanolamine amide; And / or, in step 2), the alkaline solution is a sodium hydroxide solution, wherein OH - The molar amount is equal to the total molar amount of hydroxyl groups in bisphenol A and gallic acid dipropanolamine amide.

5. The epoxy glass fiber insulation material according to claim 1, characterized in that: The modified glass fiber preparation method comprises the following steps: a. removing impurities from the glass fiber and mixing it with water to form a suspension; then adding tris base and dopamine, adjusting the pH value to 8-10, stirring the suspension to form a polydopamine layer on the surface of the glass fiber; centrifuging, filtering, washing, and drying to obtain PDA@GF; and b. ultrasonically reacting the epoxy silane coupling agent hydrolyzate with the PDA@GF, centrifuging, filtering, washing, and drying to obtain the modified glass fiber.

6. The epoxy glass fiber insulation material according to claim 5, characterized in that: The usage ratio of the glass fiber, tris base and dopamine in step a is 40g:(1.2-1.5)g:(0.4-0.6)g.

7. The epoxy glass fiber insulation material according to claim 5, characterized in that: The epoxy silane coupling agent hydrolyzate in step b is prepared by the following method: the epoxy silane coupling agent and the ethanol aqueous solution with an ethanol content of 90wt% are mixed at a solid-liquid ratio of 1g:20mL, and then the pH is adjusted to 3.5-5, and stirred at 30-50°C for 1-2h to obtain the epoxy silane coupling agent; the epoxy silane coupling agent is 10-15wt% of the glass fiber.

8. The epoxy glass fiber insulation material according to claim 7, characterized in that: The epoxy silane coupling agent is one of γ-glycidyloxypropyltrimethoxysilane, γ-glycidyloxypropyltriethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane and β-(3,4-epoxycyclohexyl)ethyltriethoxysilane.

9. A process for preparing the epoxy glass fiber insulation material according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1, preheating the modified epoxy resin at 60-70°C, adding partially fluorinated zinc oxide, vacuum degassing and dispersing to prepare a first component; Preheat the curing agent at 60-70°C, add the remaining part of zinc oxide fluoride, and then vacuum degas and disperse to obtain the second component; S2, mix the first component and the second component at 70-80°C, then add the accelerator, stir evenly, and then maintain a constant temperature and perform vacuum degassing to obtain a glue solution; S3, pour the glue solution into a dipping tank, and the modified glass fiber passes through the dipping tank at 80-85°C and is wound by a wet winding process; S4, after winding is completed, put it into a curing furnace and cure it according to the prescribed curing procedure of 100°C / 2h+120°C / 20min until it is completely gelled to obtain the epoxy glass fiber insulation material.

10. An application of the epoxy glass fiber insulation material according to any one of claims 1 to 8, characterized in that: For insulating tie rods.

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