A self-catalytic controllable curing epoxy resin composition, a preparation method and applications thereof

Abstract

The present application relates to a kind of self-catalytic controllable curing epoxy resin composition and its preparation method and application.The self-catalytic controllable curing epoxy resin composition includes epoxy resin component and curing agent component;The epoxy resin component includes the following weight fraction components: bisphenol A type epoxy resin 50-70 parts;Bisphenol F type epoxy resin 25-45 parts;Aliphatic cyclic epoxy resin 10-20 parts;Glycerol amine epoxy resin 5-10 parts;Defoaming agent 0.3-1.5 parts;The curing agent component includes the weight fraction of 90-110 parts anhydride curing agent.The self-catalytic controllable curing epoxy resin composition provided by the present application has the characteristics of low mixing viscosity, super long pot life, high temperature self-catalytic controllable curing, can be well applied to extra-high voltage electrical insulation parts, has multi-dimensional far-reaching significance in aspects such as guaranteeing power safety, promoting energy transformation and improving high-end equipment manufacturing level.

Description

Technical Field

[0001] This invention relates to the field of epoxy resin adhesive technology, and more particularly to a self-catalytically curable epoxy resin composition, its preparation method, and its application. Background Technology

[0002] Epoxy resins are widely used in aerospace, energy and chemical, power and electrical engineering, and electronic ceramics fields due to their excellent insulation properties, high mechanical strength, good thermal shock resistance, and good temperature, humidity, and frequency stability. Currently, traditional epoxy resin formulations and application processes cannot meet the production process requirements, high insulation performance, and low dielectric loss requirements of ultra-high voltage electrical insulation components. There are three main problems: (1) Traditional epoxy resins are not pure and contain a small amount of water, unreacted monomers, low molecular weight prepolymers and ultra-high molecular weight polymers, which affect the reaction rate of epoxy resin mixtures and also affect the electrical insulation performance of cured products; (2) Traditional epoxy resin curing agents are acid anhydride or amine curing agents. With the addition of fast curing or latent accelerator systems, the reaction rate of pre-epoxy resin mixtures is uncontrollable. It may start to react rapidly at room temperature or not react at room temperature. After reaching the active temperature of the accelerator, it will catalyze the reaction violently. The reaction heat release is not gradual. For UHV electrical insulation components, the uneven reaction heat release is very likely to cause stress concentration and cracking; (3) The electrical insulation performance of cured products is difficult to meet the working conditions of UHV, especially the dielectric loss is too high, which seriously affects the transmission efficiency, safety and service life of power transmission and distribution.

[0003] CN109265922A discloses a high-toughness self-catalytic epoxy resin and its preparation method. The resin comprises 1-15 parts by mass of hyperbranched polysiloxane containing various active functional groups, 60-90 parts by mass of bisphenol A type epoxy resin, and 50-60 parts by mass of anhydride-based curing agent. Because the hyperbranched polysiloxane in this resin system contains both tertiary and primary amines and other active functional groups, it effectively promotes the curing of the modified resin system and lowers the curing temperature of the epoxy resin. Furthermore, it exhibits excellent compatibility with epoxy resin, acting like soft nanoparticles, which not only avoids the agglomeration defects of solid nanoparticles but also simultaneously enhances and toughens the resin. This epoxy resin system possesses high toughness, high strength, and low curing temperature; however, it has a high mixing viscosity, rapid viscosity increase, and poor permeability, failing to meet the process requirements of ultra-high voltage electrical insulation components. The toughening effect also affects the heat resistance of the cured product, thus failing to meet the operating conditions of ultra-high voltage electrical insulation components.

[0004] CN117106160A discloses a biodegradable and recyclable autocatalytic epoxy resin and its preparation, degradation, and recycling methods. It is prepared by combining a hyperbranched polysiloxane containing thiol and imine groups, anhydride, and epoxy resin. The resin utilizes a dual-action process—thiol-epoxy click reaction and imine-catalyzed anhydride-epoxy reaction—to construct a self-catalytic multi-layered dynamic cross-linked network of HSiSB / anhydride / epoxy resin. This epoxy resin system not only achieves the degradation and recycling of thermosetting epoxy resin through amidation reaction in an organic amine nucleophile and dynamic exchange of imine bonds, but also improves the mechanical properties of the epoxy resin and imparts high-temperature resistance. However, it primarily discloses the autocatalytic reaction of the degradation and recycling process, not the autocatalytic reaction of the final epoxy resin and curing agent mixture. Furthermore, a large amount of low-molecular-weight solvent is added during the resin preparation process, which may remain in the epoxy resin and fail to meet product purity requirements.

[0005] CN118879156A discloses a method for preparing and applying a solvent-free epoxy coating composition with an ultra-long pot life. The epoxy coating composition comprises a first component and a second component. The first component includes epoxy resin, pigments, fillers, additives, liquid petroleum resin, and bifunctional glycidyl ether. The second component includes GEI-modified resin and polyamide resin. The GEI-modified resin is prepared by an addition reaction of 2-phenylimidazoline with glycerol tris(1,2-epoxy)propyl ether. The epoxy coating composition provided exhibits a significantly longer pot life than commercially available products at 30°C, making it suitable for use on steel structures in enclosed spaces such as the inner walls of pipes and ship oil tanks for corrosion and rust prevention. Furthermore, this product allows for more flexible scheduling at construction sites, reducing the risk of paint adhesion and damage to spraying equipment caused by prolonged paint storage. The coating also exhibits excellent chemical resistance and salt spray resistance. However, this disclosed product belongs to the coating industry and contains a large amount of filler, which is fundamentally different from the ultra-high voltage electrical insulation industry.

[0006] Therefore, developing a controllable curing epoxy resin with an ultra-long service life and high-temperature self-catalytic properties that can be well applied in the ultra-high voltage electrical industry is of great practical significance. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention provides a self-catalytically curable epoxy resin composition, its preparation method, and its applications. The self-catalytically curable epoxy resin composition features low mixing viscosity (wetting properties), an ultra-long pot life (penetration properties), and high-temperature self-catalytically curing capability (it reacts slowly and releases heat gradually within each temperature gradient during curing, with low temperature rise). It can be well applied to ultra-high voltage electrical insulation components (such as fiberglass bushings, AC adhesive-impregnated paper bushings, and DC adhesive-impregnated paper dry bushings), and has profound significance in multiple dimensions, including ensuring power security, promoting energy transformation, and improving the level of high-end equipment manufacturing.

[0008] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, the present invention provides a self-catalytically curable epoxy resin composition, the self-catalytically curable epoxy resin composition comprising an epoxy resin component and a curing agent component; The epoxy resin component comprises the following components in parts by weight: 50-70 parts of bisphenol A type epoxy resin; 25-45 parts of bisphenol F type epoxy resin; 10-20 parts of alicyclic epoxy resin; 5-10 parts of glyceryl amine epoxy resin; 0.3-1.5 parts of defoamer; The curing agent component includes 90-110 parts by weight of an acid anhydride curing agent.

[0009] This invention optimizes the formulation (raw material selection and content) of the epoxy resin and curing agent components in the epoxy resin composition, resulting in an epoxy resin composition with advantages such as an ultra-long pot life and high-temperature autocatalytic controllable curing. It maintains stable mechanical and electrical insulation properties even after medium- to long-term high-temperature operation. The autocatalytically controllable curing epoxy resin composition of this invention has low mixing viscosity, slow viscosity increase, and good wetting and penetration into the fiber matrix. Furthermore, its gradient temperature curing process is characterized by stable exothermic reaction, low temperature rise under each temperature gradient condition, and consistent reaction degree between the inner and outer layers, effectively reducing internal stress during the curing process and lowering the risk of cracking. Simultaneously, its preparation components do not contain organic solvents, eliminating the hazardous effects of organic solvents during curing, making it safe and environmentally friendly.

[0010] Specifically, in the self-catalytically curable epoxy resin composition provided by this invention, bisphenol A epoxy resin serves as the main resin component, exhibiting high viscosity, moderate reactivity, and gentle curing exotherm, resulting in cured products with high mechanical strength and heat resistance. Bisphenol F epoxy resin has lower viscosity, higher reactivity, faster curing, lower curing shrinkage, better toughness, and lower internal stress. Alicyclic epoxy resin has low viscosity and excellent heat resistance, but is also brittle. Glycerylamine epoxy resin possesses multiple tertiary amine structures and epoxy groups, significantly improving the crosslinking degree and heat resistance of the cured product. Defoamers reduce the surface tension of the liquid, accelerating defoaming during the impregnation process. Anhydride curing agents, with their low viscosity, reduce viscosity and improve penetration and wettability when mixed with epoxy resin components, and are used for crosslinking and curing of epoxy groups, forming a three-dimensional network structure with high mechanical strength and electrical insulation properties.

[0011] Furthermore, this invention uses glycerol amine epoxy resin in a specific mass ratio to combine with other types of epoxy resin, forming a special catalytic reaction system. The glycerol amine epoxy resin itself exerts the catalytic effect, eliminating the need for additional catalysts or other components. The resulting self-catalyzing, controllable curing epoxy resin composition can react slowly at a lower casting temperature, gradually releasing the heat of reaction. Viscosity increases slowly, and the reaction rate does not increase rapidly or become uncontrollable after raising the curing temperature. The heat release process is gradual, internal stress is low, and the shrinkage rate during curing is extremely low, thereby reducing the possibility of cracking, improving mechanical and adhesive strength, and ultimately exhibiting excellent electrical insulation properties. This ensures the stability of the ceramic insulating material during long-term high-temperature operation and extends its service life. Simultaneously, under set gradient temperature conditions, the system can also react slowly, effectively shortening the overall curing time, thereby improving production efficiency and reducing energy consumption during the preparation process.

[0012] The bisphenol A type epoxy resin in the epoxy resin component provided by the present invention can be 50 parts, 52 parts, 54 parts, 56 parts, 58 parts, 60 parts, 62 parts, 64 parts, 66 parts, 68 parts or 70 parts by weight, as well as specific values ​​between the above points. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0013] The weight percentage of bisphenol F epoxy resin in the epoxy resin component provided by this invention can be 25 parts, 27 parts, 30 parts, 32 parts, 35 parts, 37 parts, 40 parts, 42 parts, or 45 parts, as well as specific values ​​between the above-mentioned values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0014] The weight percentage of alicyclic epoxy resin in the epoxy resin component provided by this invention can be 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, or 20 parts, as well as specific values ​​between the above-mentioned values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0015] The weight percentage of glycerol amine epoxy resin in the epoxy resin component provided by this invention can be 5 parts, 5.5 parts, 6 parts, 6.5 parts, 7 parts, 7.5 parts, 8 parts, 8.5 parts, 9 parts, 9.5 parts, or 10 parts, as well as specific values ​​between the above-mentioned values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0016] The weight percentage of the defoamer in the epoxy resin component provided by this invention can be 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, 1 part, 1.1 parts, 1.2 parts, 1.3 parts, 1.4 parts, or 1.5 parts, as well as specific values ​​between the above-mentioned values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0017] The weight percentage of the anhydride curing agent in the curing agent component provided by the present invention can be 90 parts, 92 parts, 94 parts, 96 parts, 98 parts, 100 parts, 102 parts, 104 parts, 106 parts, 108 parts, or 110 parts, as well as specific values ​​between the above-mentioned values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0018] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The purpose and beneficial effects of the present invention can be better achieved and realized through the following preferred technical solutions.

[0019] As a preferred embodiment of the present invention, the bisphenol A type epoxy resin has a viscosity of 8000-13000 mPa·s at 23±2℃, an epoxy equivalent of 182-194 g / eq, and a chlorine content of ≤600 ppm.

[0020] Among these, 23±2℃ can be, for example, 21℃, 22℃, 23℃, 24℃, or 25℃; 8000-13000 mPa·s can be, for example, 8000 mPa·s, 8500 mPa·s, 9000 mPa·s, 9500 mPa·s, 10000 mPa·s, 10500 mPa·s, 11000 mPa·s, 11500 mPa·s, 12000 mPa·s, 12500 mPa·s, or 13000 mPa·s; and 182-194 g / eq can be, for example, 182 g / eq, 183 g / eq, 184 g / eq, 185 g / eq, 186 g / eq, 187 g / eq, 188 g / eq, 189 g / eq, 190 g / eq, 191 g / eq, 192 g / eq, 193 g / eq, etc. g / eq or 194 g / eq, the chlorine content can be, for example, 200 ppm, 250 ppm, 300 ppm, 350 ppm, 400 ppm, 450 ppm, 500 ppm, 550 ppm or 600 ppm, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0021] More preferably, the bisphenol A type epoxy resin has a viscosity of 9000-11000 mPa·s at 23±2℃, an epoxy equivalent of 184-192 g / eq, and a chlorine content of ≤500 ppm.

[0022] Preferably, the bisphenol F type epoxy resin has a viscosity of 5000-9000 mPa·s at 23±2℃, an epoxy equivalent of 163-177 g / eq, and a chlorine content of ≤600 ppm.

[0023] Among these, 23±2℃ can be, for example, 21℃, 22℃, 23℃, 24℃, or 25℃; 5000-9000 mPa·s can be, for example, 5000 mPa·s, 5500 mPa·s, 6000 mPa·s, 6500 mPa·s, 7000 mPa·s, 7500 mPa·s, 8000 mPa·s, 8500 mPa·s, or 9000 mPa·s; 163-177 g / eq can be, for example, 163 g / eq, 165 g / eq, 168 g / eq, 170 g / eq, 172 g / eq, 175 g / eq, or 177 g / eq; and chlorine content can be, for example, 200 ppm, 250 ppm, 300 ppm, 350 ppm, 400 ppm, 450 ppm, 500 ppm, 550 ppm, or 600 ppm. ppm, and specific point values ​​between the above point values, are not exhaustively listed in this invention due to space limitations and for the sake of brevity.

[0024] More preferably, the bisphenol F type epoxy resin has a viscosity of 6000-7500 mPa·s at 23±2℃, an epoxy equivalent of 165-175 g / eq, and a chlorine content of ≤500 ppm.

[0025] Preferably, the alicyclic epoxy resin has a viscosity of 180-600 mPa·s at 23±2℃, an epoxy equivalent of 125-150 g / eq, and a chlorine content of ≤500 ppm.

[0026] Among these, 23±2℃ can be, for example, 21℃, 22℃, 23℃, 24℃, or 25℃; 180-600 mPa·s can be, for example, 180 mPa·s, 200 mPa·s, 250 mPa·s, 300 mPa·s, 350 mPa·s, 400 mPa·s, 450 mPa·s, 500 mPa·s, 550 mPa·s, or 600 mPa·s; 125-150 g / eq can be, for example, 125 g / eq, 128 g / eq, 130 g / eq, 132 g / eq, 135 g / eq, 137 g / eq, 140 g / eq, 142 g / eq, 145 g / eq, 147 g / eq, or 150 g / eq; and chlorine content can be, for example, 200 ppm, 250 ppm, 300 ppm, 350 ppm, or 400 ppm. ppm, 450 ppm or 500 ppm, and specific point values ​​between the above point values, are not exhaustively listed in this invention for the sake of space and brevity.

[0027] More preferably, the alicyclic epoxy resin has a viscosity of 200-350 mPa·s at 23±2℃, an epoxy equivalent of 128-140 g / eq, and a chlorine content of ≤300 ppm.

[0028] Among these, 23±2℃ can be, for example, 21℃, 22℃, 23℃, 24℃, or 25℃; 200-350 mPa·s can be, for example, 200 mPa·s, 220 mPa·s, 250 mPa·s, 280 mPa·s, 300 mPa·s, 320 mPa·s, or 350 mPa·s; 128-140 g / eq can be, for example, 128 g / eq, 130 g / eq, 132 g / eq, 134 g / eq, 136 g / eq, 138 g / eq, or 140 g / eq; and chlorine content can be, for example, 50 ppm, 70 ppm, 100 ppm, 120 ppm, 150 ppm, 180 ppm, 200 ppm, 220 ppm, 250 ppm, 270 ppm, or 300 ppm. ppm, and specific point values ​​between the above point values, are not exhaustively listed in this invention due to space limitations and for the sake of brevity.

[0029] Preferably, the glycerol amine epoxy resin has a viscosity of 3000-4500 mPa·s at 50°C and an epoxy equivalent of 100-130 g / eq.

[0030] Among them, 3000-4500 mPa·s can be, for example, 3000 mPa·s, 3200 mPa·s, 3400 mPa·s, 3600 mPa·s, 3800 mPa·s, 4000 mPa·s, 4200 mPa·s or 4500 mPa·s, and 100-130 g / eq can be, for example, 100 g / eq, 105 g / eq, 110 g / eq, 115 g / eq, 120 g / eq, 125 g / eq or 130 g / eq, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific point values ​​included in the range.

[0031] More preferably, the glycerol amine epoxy resin has a viscosity of 3300-3800 mPa·s at 50°C and an epoxy equivalent of 100-120 g / eq.

[0032] Preferably, the glycerolamine epoxy resin is a multifunctional glycerolamine epoxy resin, and the functionality of the multifunctional glycerolamine epoxy resin is 3-4, for example, 3 or 4, and more preferably 4.

[0033] Preferably, the defoamer is a polymeric defoamer that has good compatibility with epoxy resin.

[0034] It should be noted that there is no special limitation on the specific type of polymeric defoamer in this invention. Commonly used polymeric defoamers in the art are applicable, including but not limited to BYK-A501 and / or BYK-A535.

[0035] Preferably, the solid content of the defoamer is ≥99.8%, for example, it can be 99.8%, 99.85%, 99%, 99.95% or 100%, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0036] Preferably, the anhydride curing agent comprises methylhexahydrophthalic anhydride and / or methylnadic anhydride, and more preferably a combination of methylhexahydrophthalic anhydride and methylnadic anhydride.

[0037] In this invention, the preferred anhydride curing agent is a combination of methylhexahydrophthalic anhydride and methylnadic anhydride, which can better adjust the viscosity and purity of the curing agent system (lower viscosity, higher purity), thereby making it better compatible with epoxy resin components, which is more conducive to subsequent cross-linking and curing, and thus obtaining higher mechanical strength and electrical insulation properties.

[0038] Preferably, the viscosity of the anhydride curing agent at 23±2℃ is 40-70 mPa·s, the content of free acid is ≤0.6%, and the iodine value is ≤1.5%. Wherein, 23±2℃ can be, for example, 21℃, 22℃, 23℃, 24℃, or 25℃; 40-70 mPa·s can be, for example, 40 mPa·s, 45 mPa·s, 50 mPa·s, 55 mPa·s, 60 mPa·s, 65 mPa·s, or 70 mPa·s; the content of free acid can be, for example, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, or 0.6%; and the iodine value can be, for example, 0.1%, 0.25%, 0.5%, 0.7%, 1%, 1.15%, 1.3%, or 1.5%, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific values ​​included in the range.

[0039] More preferably, the anhydride curing agent has a viscosity of 45-60 mPa·s at 23±2℃, a free acid content of ≤0.5%, and an iodine value of ≤1.4%.

[0040] This invention limits the free acid and iodine value of the anhydride curing agent, thereby obtaining a high-purity anhydride curing agent.

[0041] This invention regulates the composition, viscosity, epoxy value, chlorine content, and functionality of various raw materials in self-catalytically curable epoxy resins. By scientifically combining and rationally distributing resins with different molecular chains, viscosities, functionalities, and reactivity with self-catalytic monomers (multifunctional glycerolamine epoxy resins), it reduces the mixed viscosity, reactivity, and heat release of ultra-long pot life, high-temperature self-catalytically curable epoxy resins. This improves the wetting and penetration properties of ultra-long pot life, high-temperature self-catalytically curable epoxy resins, and the stability of curing heat release under gradient temperatures, thus reducing the possibility of curing shrinkage and cracking. This invention uses high-purity raw materials and a gentle reaction rate, resulting in a uniform and dense cured product with high electrical insulation properties and low dielectric loss, effectively reducing electrical losses during ultra-high voltage power transmission.

[0042] In a second aspect, the present invention provides a method for preparing the self-catalytically curable epoxy resin composition as described in the first aspect, the preparation method comprising the following steps: Preparation of epoxy resin components: The epoxy resin components are obtained by mixing bisphenol A type epoxy resin, bisphenol F type epoxy resin, alicyclic epoxy resin, glycerol amine epoxy resin and defoamer according to the formula. Preparation of curing agent components: Take the acid anhydride curing agent according to the formula to obtain the curing agent components.

[0043] Preferably, the bisphenol A type epoxy resin, bisphenol F type epoxy resin and alicyclic epoxy resin further include a pretreatment step before mixing.

[0044] Preferably, the pretreatment step includes mixing bisphenol A epoxy resin, bisphenol F epoxy resin and alicyclic epoxy resin, followed by purification and screening to obtain a light phase component.

[0045] Preferably, the purification screening includes sequential steps of thin-film evaporation and distillation.

[0046] Preferably, the temperature for film evaporation is 180-190°C, for example, it can be 180°C, 181°C, 182°C, 183°C, 184°C, 185°C, 186°C, 187°C, 188°C or 190°C, as well as specific values ​​between the above points. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0047] Preferably, the distillation temperature is 210-240℃ and the vacuum degree is 50-200 Pa. The 210-240℃ can be, for example, 210℃, 212℃, 215℃, 217℃, 220℃, 222℃, 225℃, 228℃, 230℃, 232℃, 235℃, 237℃, or 240℃; the 50-200 Pa can be, for example, 50 Pa, 80 Pa, 100 Pa, 120 Pa, 140 Pa, 160 Pa, 180 Pa, or 200 Pa, as well as specific values ​​between the above ranges. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific values ​​included in the range.

[0048] This invention purifies and screens bisphenol A epoxy resin, bisphenol F epoxy resin, and alicyclic epoxy resin by combining thin-film evaporation (180-190℃) with high-temperature (210-240℃) vacuum (50-200 Pa) short-path distillation. High-temperature thin-film evaporation effectively removes impurities such as moisture, residual bisphenol A, and epichlorohydrin from the epoxy resin components. High-temperature vacuum short-path distillation separates single-molecule bisphenol A epoxy, ultra-high molecular weight, and high-viscosity epoxy resin components, thereby obtaining a light phase component with lower viscosity and suitable molecular weight (high-purity epoxy resin with narrow molecular weight distribution). This ensures the purity of the material, reduces the influence of impurities on reactivity, and gives the resulting self-catalytically curable epoxy resin composition better mechanical and electrical insulation properties.

[0049] Preferably, the preparation of the epoxy resin components further includes a vacuum treatment step after mixing.

[0050] Preferably, the vacuum treatment temperature in the preparation of the epoxy resin component is 55-65℃, and the vacuum degree is 300-500 Pa. Wherein, 55-65℃ can be, for example, 55℃, 56℃, 57℃, 58℃, 59℃, 61℃, 62℃, 63℃, 64℃, or 65℃, and 300-500 Pa can be, for example, 300 Pa, 320 Pa, 340 Pa, 360 Pa, 380 Pa, 400 Pa, 420 Pa, 450 Pa, 480 Pa, or 500 Pa, as well as specific values ​​between the above points. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific values ​​included in the range.

[0051] Preferably, the vacuum treatment in the preparation of the epoxy resin component is carried out under stirring for a time of 30-60 min, for example, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min or 60 min, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0052] The epoxy resin component in this invention is prepared using vacuum treatment, which can reduce the viscosity of several resin raw materials by heating; reduce the interfacial tension between different resin molecules and reduce the intermolecular distance by removing air through vacuum; and accelerate the uniform mixing and compatibility between different resin molecules by stirring.

[0053] Preferably, the preparation of the curing agent component further includes vacuum treatment of the acid anhydride curing agent.

[0054] The epoxy resin component of the present invention employs a vacuum treatment method to remove moisture and low molecular weight impurities from the raw material components (especially glycerol amine epoxy resins), thereby further screening and refining the epoxy resin component, and ultimately enabling the obtained self-catalytically curable epoxy resin composition to obtain better mechanical strength and electrical insulation properties.

[0055] Preferably, the vacuum degree of the vacuum treatment in the preparation of the curing agent component is 300-500 Pa, for example, it can be 300 Pa, 320 Pa, 340 Pa, 360 Pa, 380 Pa, 400 Pa, 430 Pa, 450 Pa, 480 Pa or 500 Pa, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0056] In this invention, the curing agent component employs vacuum treatment for the anhydride curing agent, which can eliminate water vapor and low-molecular-weight anhydride molecules in the curing agent component, eliminate the catalytic reaction of water vapor with epoxy and anhydride curing agent, and reduce the influence of low-molecular-weight anhydride on the degree of crosslinking of the cured product.

[0057] Preferably, the vacuum treatment in the preparation of the curing agent component is carried out under stirring for a time of 30-60 min, for example, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min or 60 min, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0058] Thirdly, the present invention provides an application of the self-catalytically curable epoxy resin composition as described in the first aspect in ultra-high voltage electrical insulation components.

[0059] It should be noted that the "ultra-high voltage" in the ultra-high voltage electrical insulation components described in this invention refers to 1000kV AC or ±800 kV DC, which is consistent with the ultra-high voltage range in Chinese national standard GB / T 156-2017 "Standard Voltage" and IEC 60038.

[0060] Fourthly, the present invention provides a method for applying the self-catalytically curable epoxy resin composition as described in the first aspect, the method comprising mixing, vacuum casting, impregnation and curing the self-catalytically curable epoxy resin composition as described in the first aspect.

[0061] Preferably, the mixing process includes vacuum degassing after mixing the epoxy resin component and the curing agent component.

[0062] Preferably, the mass ratio of epoxy resin component to curing agent component in the mixed adhesive is 100:(90-110), wherein (90-110) can be, for example, 90, 92, 94, 96, 98, 100, 102, 104, 106 or 110, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0063] Preferably, the mixing temperature in the mixed adhesive is 45-60℃ and the vacuum degree is 50-200 Pa. The 45-60℃ can be, for example, 45℃, 48℃, 50℃, 52℃, 54℃, 56℃, 58℃, or 60℃, and the 50-200 Pa can be, for example, 50 Pa, 80 Pa, 100 Pa, 120 Pa, 140 Pa, 160 Pa, 180 Pa, or 200 Pa, as well as specific values ​​between these ranges. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific values ​​included in the ranges.

[0064] Preferably, the vacuum degassing temperature is 45-60℃ and the vacuum degree is 50-200 Pa. For example, 45-60℃ can be 45℃, 48℃, 50℃, 52℃, 54℃, 56℃, 58℃ or 60℃, and 50-200 Pa can be 50 Pa, 80 Pa, 100 Pa, 120 Pa, 140 Pa, 160 Pa, 180 Pa or 200 Pa, as well as specific values ​​between the above points. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0065] It should be noted that in actual production applications, the mixing can be carried out by single-component constant temperature (45-60℃) vacuum (50-200 Pa) degassing, and after two-component metering by a metering pump, it is mixed by a static mixer under vacuum at constant temperature; and the temperature of the single component, the mixing temperature, and the vacuum degree can be determined according to the size of the casting and the casting volume. When the amount of casting in a single batch is small, the upper limit of the temperature can be used, and the vacuum degree is unlimited.

[0066] Preferably, the vacuum casting includes continuous casting at 45-55℃ and 100-300 Pa for 5-10 days until the workpiece is filled. Here, 45-55℃ can be, for example, 45℃, 46℃, 47℃, 48℃, 49℃, 51℃, 52℃, 53℃, 54℃, or 55℃; 100-300 Pa can be, for example, 100 Pa, 120 Pa, 140 Pa, 160 Pa, 180 Pa, 200 Pa, 230 Pa, 250 Pa, 280 Pa, or 300 Pa; and 5-10 days can be, for example, 5 days, 6 days, 7 days, 8 days, 9 days, or 10 days, as well as specific values ​​between the above-mentioned values. For space limitations and for the sake of brevity, this invention will not exhaustively list all the specific values ​​included in the range.

[0067] It should be noted that in actual production applications, the casting process can be determined according to the size of the casting part and the casting volume. When the amount of casting part in a single casting is small, the upper limit of temperature, the upper limit of vacuum degree, and the lower limit of casting time can be used.

[0068] Preferably, the impregnation and curing process includes impregnation at 50-60°C for 3-6 days to complete the impregnation and pre-gelling process; gel curing at 60-70°C for 1-2 days, curing at 70-90°C for 1-2 days, curing at 90-110°C for 1-2 days, curing at 110-130°C for 2-3 days, and curing at 130-80°C for 3-5 days (with slow cooling).

[0069] Among them, 50-60℃ can be 50℃, 51℃, 52℃, 53℃, 54℃, 55℃, 56℃, 57℃, 58℃, 59℃ or 60℃; 3-6 days can be 3 days, 3.5 days, 4 days, 4.5 days, 5 days, 5.5 days or 6 days; 60-70℃ can be 60℃, 61℃, 62℃, 63℃, 64℃, 65℃, 66℃, 67℃, 68℃, 69℃ or 70℃; 1-2 days can be 1 day, 1.5 days or 2 days; 70-90℃ can be 70℃, 72℃, 75℃, 78℃, 80℃, 82℃, 865℃, 88℃ or 90℃; 90-110℃ can be 90℃, 92℃, 95℃, 98℃, 100℃ or 110℃. ℃, 102℃, 105℃, 108℃ or 110℃, 110-130℃ can be, for example, 110℃, 112℃, 114℃, 116℃, 118℃, 120℃, 122℃, 124℃, 126℃, 128℃ or 130℃, 2-3 days can be, for example, 2 days, 2.5 days or 3 days, 130-80℃ can be, for example, 130℃, 125℃, 120℃, 115℃, 110℃, 105℃, 100℃, 95℃, 90℃, 85℃ or 80℃, 3-5 days can be, for example, 3 days, 3.5 days, 4 days, 4.5 days or 5 days, and specific point values ​​between the above point values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific point values ​​included in the range.

[0070] It should be noted that in actual production applications, the impregnation and curing processes can be determined according to the size of the casting and the amount of casting. When the amount of casting in a single batch is small, the upper limit of the temperature and the lower limit of the time for each gradient can be used.

[0071] It should be noted that the impregnation and curing conditions provided by this invention are parameter settings for actual production applications. For other application scenarios such as laboratory experiments, the corresponding parameter settings can be adjusted adaptively according to the actual situation.

[0072] Compared with the prior art, the present invention has at least the following beneficial effects: (1) The ultra-long service life and high temperature self-catalytic controllable curing epoxy resin provided by the present invention adopts a specific combination of raw materials and a scientific formulation system. The types, viscosity, epoxy value, chlorine content, functionality, free acid and iodine value of raw materials are strictly controlled. Through the relevant performance control of raw materials, the performance consistency of the final product is ensured. It has excellent mechanical strength and electrical insulation properties. Its viscosity is <60 mPa·s, the time for the viscosity to increase to 500 mPa·s at 60℃ is 70-92 h, the maximum exothermic temperature at 60℃ for 4 days is 60-66℃, the gel time at 140℃ is 4-6.5 h, the Tg of the cured product after curing is 135-150℃, the flexural strength is 120-130 MPa, and the dielectric loss is 0.27-0.37%. Meanwhile, the raw materials contain no organic solvents and have no odor, which can eliminate the safety and environmental problems of ultra-long pot life and high temperature self-catalytic controllable curing epoxy resins during transportation and use; moreover, since they do not contain organic matter, there are no VOC emissions during the later use and curing process of the product, which greatly improves safety. (2) The preparation method of ultra-long pot life and high temperature self-catalytic controllable curing epoxy resin provided by the present invention adopts a scientifically designed purification process to remove impurities, reduce the influence of impurities on the curing speed, and reduce the adverse effects on the mechanical strength and electrical insulation properties of the final cured product. (3) The scientific and reasonable formulation of the ultra-long service life and high-temperature self-catalytic controllable curing epoxy resin provided by the present invention adjusts the viscosity of the mixture by combining different resin systems, and uses a special self-catalytic curing agent system to achieve an ultra-long service life and high-temperature self-catalytic curing at the operating temperature. It can effectively control the stable reaction heat release under each temperature gradient, reduce the temperature rise of each curing temperature range, thereby reducing the internal stress and shrinkage rate of curing and reducing the possibility of cracking. The cross-linking degree of the inner and outer resins is close, and the curing is uniform and consistent, which can improve the mechanical strength and bonding strength, and has excellent electrical insulation performance, ensuring the stability and reliability of the insulation performance of the UHV electrical insulation components during long-term high-temperature operation. In addition, the insulation components prepared by the specific formulation and process of the present invention have a high heat resistance temperature and low dielectric loss, which can improve the power transmission efficiency. Attached Figure Description

[0073] Figure 1 The application flowchart of the self-catalytically curable epoxy resin composition provided by the present invention is shown. Detailed Implementation

[0074] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0075] Unless otherwise specified, the materials and equipment involved in the following detailed embodiments are all conventional materials and equipment in the art and will not affect the technical effects of the present invention.

[0076] like Figure 1 The diagram shown is an application flow chart of the self-catalytically curable epoxy resin composition provided by the present invention.

[0077] Unless otherwise specified, all reagents and raw materials used in the following examples and comparative examples are commercially available products. Some raw material information is as follows: Bisphenol A type epoxy resin: NPEL128E, with a viscosity of 10400 mPa·s at 25℃, an epoxy equivalent of 190.1 g / eq, and a chlorine content of 320 ppm, purchased from Nan Ya Plastics (Kunshan) Co., Ltd. Bisphenol F type epoxy resin: YDF170, with a viscosity of 7050 mPa·s at 25℃, an epoxy equivalent of 168.3 g / eq, and a chlorine content of 390 ppm, purchased from Kunshan Guodu Chemical Co., Ltd. Alicyclic epoxy resin: TTA21P, with a viscosity of 240 mPa·s at 25℃, an epoxy equivalent of 129.3 g / eq, and a chlorine content of 100 ppm, purchased from Jiangsu Taiter New Material Technology Co., Ltd. Glycerylamine epoxy resin; AG-80, with a viscosity of 3500 mPa·s at 50℃ and an epoxy equivalent of 117.6 g / eq, purchased from Shanghai Synthetic Resin Research Institute; Defoamer: BYK-A501, purchased from BYK Chemicals; Anhydride curing agent: Methylhexahydrophthalic anhydride AMH-850, with a viscosity of 48 mPa·s at 25℃, a free acid content of 0.52%, and an iodine value of 1.34%, purchased from Zhejiang Alpha Chemical Co., Ltd.

[0078] Example 1 This embodiment provides a self-catalytically curable epoxy resin composition and its preparation method, wherein the self-catalytically curable epoxy resin composition includes an epoxy resin component and a curing agent component; The epoxy resin component comprises the following components in parts by weight: Bisphenol A type epoxy resin NPEL128E 60 parts; 35 parts of bisphenol F type epoxy resin YDF170; 15 parts of alicyclic epoxy resin TTA21P; 7 parts of glycerol amine epoxy resin AG-80; 0.5 parts of defoamer BYK-A501; The curing agent component includes 95 parts by weight of methylhexahydrophthalic anhydride.

[0079] The preparation method of the self-catalytically curable epoxy resin composition includes the following steps: Preparation of epoxy resin component: Bisphenol A type epoxy resin, bisphenol F type epoxy resin and alicyclic epoxy resin were mixed according to the formula, and then subjected to thin film evaporation at 185°C and distillation at 230°C and 100 Pa to obtain light phase component; the light phase component was transferred to a stirred tank at 60°C, AG-80 and BYK-A501 were added, and the mixture was stirred under vacuum at 400 Pa for 45 min to obtain epoxy resin component; Preparation of curing agent component: Methylhexahydrophthalic anhydride was stirred under vacuum at 400 Pa for 45 min according to the formula to obtain the curing agent component.

[0080] Example 2 This embodiment provides a self-catalytically curable epoxy resin composition and its preparation method, wherein the self-catalytically curable epoxy resin composition includes an epoxy resin component and a curing agent component; The epoxy resin component comprises the following components in parts by weight: 50 parts of bisphenol A type epoxy resin NPEL128E; 45 parts of bisphenol F type epoxy resin YDF170; 15 parts of alicyclic epoxy resin TTA21P; 7 parts of glycerol amine epoxy resin AG-80; 0.3 parts of defoamer BYK-A501; The curing agent component includes 95 parts by weight of methylhexahydrophthalic anhydride.

[0081] The preparation method of the self-catalytically curable epoxy resin composition includes the following steps: Preparation of epoxy resin component: Bisphenol A type epoxy resin, bisphenol F type epoxy resin and alicyclic epoxy resin were mixed according to the formula, and then subjected to thin film evaporation at 180°C and distillation at 210°C and 200 Pa to obtain light phase component; the light phase component was transferred to a stirred tank at 55°C, AG-80 and BYK-A501 were added, and the mixture was stirred under vacuum at 300 Pa for 60 min to obtain epoxy resin component; Preparation of curing agent component: Methylhexahydrophthalic anhydride was stirred under vacuum at 300 Pa for 60 min according to the formula to obtain the curing agent component.

[0082] Example 3 This embodiment provides a self-catalytically curable epoxy resin composition and its preparation method, wherein the self-catalytically curable epoxy resin composition includes an epoxy resin component and a curing agent component; The epoxy resin component comprises the following components in parts by weight: 70 parts of bisphenol A type epoxy resin NPEL128E; 25 parts of bisphenol F type epoxy resin YDF170; 15 parts of alicyclic epoxy resin TTA21P; 7 parts of glycerol amine epoxy resin AG-80; 0.8 parts of defoamer BYK-A501; The curing agent component includes 95 parts by weight of methylhexahydrophthalic anhydride.

[0083] The preparation method of the self-catalytically curable epoxy resin composition includes the following steps: Preparation of epoxy resin component: Bisphenol A type epoxy resin, bisphenol F type epoxy resin and alicyclic epoxy resin were mixed according to the formula, and then subjected to thin film evaporation at 190℃ and distillation at 240℃ and 50 Pa to obtain light phase component; the light phase component was transferred to a stirred tank at 65℃, AG-80 and BYK-A501 were added, and the mixture was stirred under vacuum at 500 Pa for 30 min to obtain epoxy resin component; Preparation of curing agent component: Methylhexahydrophthalic anhydride was stirred under vacuum at 500 Pa for 30 min according to the formula to obtain the curing agent component.

[0084] Example 4 This embodiment provides a self-catalytically curable epoxy resin composition and its preparation method. The only difference between this embodiment and Example 1 is that the weight of the alicyclic epoxy resin TTA21P is adjusted from 15 parts to 10 parts. The other raw materials, addition amounts and preparation methods are the same as in Example 1.

[0085] Example 5 This embodiment provides a self-catalytically curable epoxy resin composition and its preparation method. The only difference between this embodiment and Example 1 is that the weight of the alicyclic epoxy resin TTA21P is adjusted from 15 parts to 20 parts. The other raw materials, addition amounts and preparation methods are the same as in Example 1.

[0086] Example 6 This embodiment provides a self-catalytically curable epoxy resin composition and its preparation method. The only difference between this embodiment and Example 1 is that the weight of glycerol amine epoxy resin AG-80 is adjusted from 7 parts to 10 parts. All other raw materials, addition amounts, and preparation methods are the same as in Example 1.

[0087] Example 7 This embodiment provides a self-catalytically curable epoxy resin composition and its preparation method. The only difference between this embodiment and Example 1 is that the weight of glycerol amine epoxy resin AG-80 is adjusted from 7 parts to 5 parts. All other raw materials, addition amounts, and preparation methods are the same as in Example 1.

[0088] Example 8 This embodiment provides a self-catalytically curable epoxy resin composition and its preparation method. The only difference between this embodiment and Example 1 is that the weight of methylhexahydrophthalic anhydride is adjusted from 95 parts to 110 parts. The other raw materials, addition amounts and preparation methods are the same as in Example 1.

[0089] Example 9 This embodiment provides a self-catalytically curable epoxy resin composition and its preparation method. The only difference between this embodiment and Example 1 is that the weight of methylhexahydrophthalic anhydride is adjusted from 95 parts to 90 parts. The other raw materials, addition amounts, and preparation methods are the same as in Example 1.

[0090] Example 10 This embodiment provides a self-catalytically curable epoxy resin composition and its preparation method. The only difference between this embodiment and Example 1 is that 95 parts of methylhexahydrophthalic anhydride are adjusted to a combination of 90 parts of methylhexahydrophthalic anhydride and 5 parts of methylnadic anhydride (purchased from Puyang Huicheng Electronic Materials Co., Ltd.). The other raw materials, addition amounts and preparation methods are the same as in Example 1.

[0091] Example 11 This embodiment provides a self-catalytically curable epoxy resin composition and its preparation method. The only difference between this embodiment and Example 1 is that the preparation method of the epoxy resin component is adjusted as follows: bisphenol A type epoxy resin, bisphenol F type epoxy resin and alicyclic epoxy resin are evaporated in thin film at 185°C and distilled at 230°C and 400 Pa to obtain a light phase component. Other raw materials, addition amounts and preparation methods are the same as in Example 1.

[0092] Comparative Example 1 This comparative example provides an epoxy resin composition and its preparation method. The only difference between this composition and Example 1 is that bisphenol F type epoxy resin YDF170 is not added, and its reduced weight parts are allocated to bisphenol A type epoxy resin NPEL128E. Other raw materials, addition amounts, and preparation methods are the same as in Example 1.

[0093] Comparative Example 2 This comparative example provides an epoxy resin composition and its preparation method. The only difference between this composition and Example 1 is that the alicyclic epoxy resin TTA21P is not added, and its reduced weight parts are allocated to the bisphenol A type epoxy resin NPEL128E. The other raw materials, addition amounts and preparation methods are the same as in Example 1.

[0094] Comparative Example 3 This comparative example provides an epoxy resin composition and its preparation method. The only difference between this composition and Example 1 is that glycerol amine epoxy resin AG-80 is not added, and its reduced weight parts are allocated to bisphenol A type epoxy resin NPEL128E. Other raw materials, addition amounts, and preparation methods are the same as in Example 1.

[0095] Comparative Example 4 This comparative example provides an epoxy resin composition and its preparation method. The only difference between this composition and Example 1 is that the weight of the glycerol amine epoxy resin AG-80 is adjusted from 7 parts to 11 parts, while the other raw materials, addition amounts, and preparation methods are the same as in Example 1.

[0096] Comparative Example 5 This comparative example provides an epoxy resin composition and its preparation method. The only difference between this composition and Example 1 is that the weight of glycerol amine epoxy resin AG-80 is adjusted from 7 parts to 4 parts, while the other raw materials, addition amounts, and preparation methods are the same as in Example 1.

[0097] Comparative Example 6 This comparative example provides a self-catalytically curable epoxy resin composition and its preparation method. The only difference between this example and Example 1 is that 95 parts of methylhexahydrophthalic anhydride are replaced with 95 parts of methylnadic anhydride. All other raw materials, amounts added, and preparation methods are the same as in Example 1.

[0098] Liquid sample testing: The epoxy resin components and curing agent components in the epoxy resin compositions provided in Examples 1-11 and Comparative Examples 1-6 were mixed at 50°C and 100 Pa (the mass ratio of epoxy resin component to curing agent component in each example and comparative example was 100 / 95 for Examples 1-7, 100 / 110 for Example 8, 100 / 90 for Example 9, 10 / 95 for Examples 10 and 11, and 100 / 95 for Comparative Examples 1-6) to obtain a mixture. The performance of the resulting liquid was tested using the following methods / standards: (1) Viscosity: Viscosity and viscosity growth test at 60°C (time for viscosity to grow to 500 mPa·s) was performed in accordance with ISO 3219. (2) Gel time: The gel time at 140℃ was tested according to ISO 9396; (3) Reaction exothermic (maximum exothermic temperature): Take 1 kg of the mixture and place it in a metal container with a diameter of 110 mm and a height of 130 mm. Place it in a constant temperature oven at 60℃ and place the thermocouple probe in the center of the liquid. Record the temperature after 4 days.

[0099] Curing and performance testing: The mixtures from the above liquid sample tests were injected into flat molds with thicknesses of 4 mm and 2 mm, respectively. Vacuum degassing was performed at 60℃ and 100 Pa for 30 min, followed by oven curing under the following conditions: 60℃ for 72 h + 90℃ for 12 h + 110℃ for 12 h + 130℃ for 12 h + 170℃ for 12 h. The resulting cured products underwent performance testing using the following methods / standards: (4) Glass transition temperature (Tg): The Tg of the cured product was tested according to ISO 11357-2; (5) Bending strength: The bending strength of the cured product shall be tested in accordance with ISO 178; (6) Dielectric loss: The dielectric loss of the cured material shall be tested in accordance with GB / T 31838.6.

[0100] The test results are shown in Table 1 below.

[0101] Table 1 According to the test results in Table 1: (1) As can be seen from Examples 1 to 11, the present invention optimizes the formulation (raw material selection + content) of epoxy resin components and curing agent components in the epoxy resin composition, so that the resulting epoxy resin composition has the advantages of ultra-long pot life and high-temperature autocatalytic controllable curing. Its viscosity is <60 mPa·s, the time for viscosity to increase to 500 mPa·s at 60℃ is 70-92 h, the maximum exothermic temperature at 60℃ for 4 days is 60-66℃, the gel time at 140℃ is 4-6.5 h, the Tg of the cured product after curing is 135-150℃, the flexural strength is 120-130 MPa, and the dielectric loss is 0.27-0.37%.

[0102] (2) As can be seen from Examples 1-3, as the amount of bisphenol A epoxy resin increases from 50 parts to 70 parts, while the amount of bisphenol F epoxy resin decreases from 45 parts to 25 parts, the initial viscosity of the mixture increases, the viscosity increases faster at 60°C, the gel time changes less, the exothermic reaction temperature is close, the Tg of the cured product gradually increases, the flexural strength also increases slightly, and the dielectric loss remains basically stable. This is because bisphenol A epoxy resin itself has a high viscosity, a rigid molecular structure, a reasonable molecular weight distribution, and the cured product has high mechanical strength.

[0103] (3) A comparison of Examples 1 with Examples 4 and 5 shows that as the amount of alicyclic epoxy resin increases from 10 parts to 20 parts while the rest remain unchanged, the initial viscosity of the mixture decreases, the viscosity increase at 60°C slows down, the gelation time becomes longer, the exothermic reaction temperatures approach each other, the Tg of the cured product increases significantly, the flexural strength first increases and then decreases, and the dielectric loss remains basically stable. This is because alicyclic epoxy resin itself has low viscosity, small molecular weight, and a strong cyclic rigidity, resulting in a high crosslinking density in the cured product, thus leading to a higher Tg and mechanical strength. At the same time, excessive alicyclic epoxy resin increases the brittleness of the cured product, making it prone to cracking.

[0104] (4) A comparison of Examples 1 with Examples 6 and 7 shows that when the proportion of glycerolamine epoxy resin is changed from 5 parts to 7 parts to 10 parts, the initial viscosity of the mixture remains basically unchanged, the viscosity increase is significantly accelerated, the gel time is also rapidly shortened, and the exothermic reaction temperature rises significantly. This indicates that glycerolamine epoxy resin can accelerate the reaction between epoxy resin and curing agent. The Tg of the cured product increases significantly, the flexural strength remains basically unchanged, and the dielectric loss increases slightly. This is because glycerolamine epoxy resin has a tertiary amine molecular structure and epoxy groups. Tertiary amines exhibit strong nucleophilicity, attacking the carbonyl carbon of acid anhydrides, opening the anhydride ring, forming a carboxylate-ammonium cation pair, which undergoes a ring-opening reaction with the epoxy group. This alternating ring-opening reaction forms a chain reaction, constructing a cross-linked network. The higher the content of glycerolamine epoxy resin, the more nucleophilic sites are formed, and the easier it is to accelerate the cross-linking reaction between epoxy groups and acid anhydrides.

[0105] (5) A comparison of Examples 1 with Examples 8 and 9 shows that when the proportion of the curing agent is changed from 90 parts to 95 parts to 110 parts, the initial viscosity of the mixture decreases significantly, the viscosity increase slows down, the gelation time is slightly prolonged, and the exothermic reaction temperature remains basically unchanged. This indicates that even if the amount of low-viscosity curing agent is increased, it will not accelerate the reaction; on the contrary, low viscosity can delay the viscosity increase. Excessive curing agent leads to a decrease in the Tg and mechanical strength of the cured product, and a slight increase in the dielectric loss. This is because excessive curing agent results in a low degree of crosslinking with epoxy groups, and the spatial network structure is not stable enough after heating.

[0106] (6) By comparing Example 1 with Example 10 and Comparative Example 6, it can be seen that the anhydride curing agent used in Example 10 is a combination of methylhexahydrophthalic anhydride and methylnadic anhydride, and the measured Tg and flexural strength of the cured product are significantly increased; while the anhydride curing agent in Comparative Example 6 is a single methylnadic anhydride, and the mixed viscosity of the epoxy resin composition obtained by it increases significantly, which will affect the wetting and penetration in the production process. At the same time, the viscosity growth is also faster, and the medium loss increases. This is because compared with methylhexahydrophthalic anhydride, the molecular structure of methylnadic anhydride contains bicyclic rings, and its viscosity is larger. Due to the steric hindrance effect, the reactivity is slightly lower, the viscosity growth is slightly slower, and the gelation is slower. However, due to the higher initial viscosity, the overall viscosity growth trend is more obvious. Moreover, due to the presence of a large number of bicyclic structures in the molecular structure of the cured product, its rigidity is stronger, the Tg is significantly increased, the steric hindrance is large and the crosslinking density is slightly lower, resulting in a significant increase in medium loss. This invention demonstrates that by selecting the type of anhydride curing agent, it can better match with other components, thereby further improving the high-temperature resistance and mechanical strength of the cured product while ensuring suitable viscosity, ultra-long pot life and high-temperature autocatalytic controllable curing.

[0107] (7) By comparing Example 1 and Example 11, it can be seen that when the purification process conditions of the initial resin are changed and the vacuum environment is reduced, the impurities and light phase components in the resin raw material cannot be completely separated. The resin contains a higher proportion of medium and low molecular weight resins, the mixed viscosity is slightly lower, and the viscosity increases and gelation is accelerated due to the influence of impurities. The medium loss of the cured product increases significantly.

[0108] (8) By comparing Example 1 with Comparative Examples 1 and 2, it can be seen that when the amount of bisphenol F epoxy resin or alicyclic epoxy resin is 0, the viscosity of the mixture increases significantly, and the increase is more obvious in Comparative Example 2. The viscosity increases faster, the gel time is shorter, and the exothermic reaction temperature decreases. This is because the viscosity of bisphenol F epoxy resin and alicyclic epoxy resin is lower than that of bisphenol A epoxy resin, and their reactivity is also slightly higher, resulting in faster viscosity increase. For the Tg of the cured product, Comparative Example 1 increases, while Comparative Example 2 decreases significantly. For the flexural strength, Comparative Example 1 decreases slightly while Comparative Example 2 increases slightly. This is because the molecular structure of bisphenol F epoxy resin has no methyl side chains, has a compact structure, low steric hindrance, and more flexible chain segments. The cross-linking network of the cured product can deform when heated, resulting in a slightly lower Tg, better toughness, and slightly lower strength. On the other hand, the molecular structure of alicyclic epoxy is cyclic, with stronger rigidity. The cross-linking network of the cured product is denser, resulting in higher mechanical strength, better heat resistance, and greater brittleness. The increased media loss in both Comparative Example 1 and Comparative Example 2 may be due to the high viscosity of the mixed system, which caused the rapid gelation and the formation of tiny air gaps in some areas.

[0109] (9) By comparing Examples 1, 6, and 7 with Comparative Examples 3, 4, and 5, it can be seen that when the content of glycerolamine epoxy resin is too high (Comparative Example 4), the viscosity increases very rapidly, the gel time shortens rapidly, the reaction exothermic temperature rises significantly, the Tg of the cured product increases, the flexural strength decreases slightly, and the dielectric loss increases. At this time, excessive catalyst and too many active crosslinking points will lead to disordered growth of chain segments in the curing reaction, increased reaction exothermic heat, wider degree of polymerization distribution, and decreased overall performance. When the content of glycerolamine epoxy resin is too low (Comparative Example 5), the viscosity increases more slowly, the gel time increases significantly, the reaction exothermic temperature decreases, the Tg and flexural strength of the cured product decrease, and the dielectric loss increases. Furthermore, when the amount of polyfunctional glycerolamine compound is 0 (Comparative Example 3), the viscosity increases very slowly, the gel time is significantly longer, and the exothermic reaction temperature is lower. This is because without polyfunctional glycerolamine compound, tertiary amine free radical electron pairs cannot be formed, making it difficult to catalyze the reaction between epoxy resin and acid anhydride curing agent. This further demonstrates the autocatalytic effect of polyfunctional glycerolamine compound in the reaction system. At the same time, the Tg and flexural strength of the cured product decrease significantly, mainly due to the lack of catalyst. The epoxy resin and curing agent have low reactivity, and the cross-linking curing is insufficient, failing to form a complete spatial cross-linked network structure, thus increasing the dielectric loss.

[0110] In summary, by optimizing the formulation (raw material selection and content) of the epoxy resin component and curing agent component of the epoxy resin composition and combining it with a specific preparation method, the present invention enables the obtained epoxy resin composition to obtain a more suitable viscosity (45-57 mPa·s) and viscosity growth time (76-91h for viscosity to grow to 500 mPa·s at 60℃), and the cured product has a lower medium loss (0.27-0.32%).

[0111] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A self-catalytically curable epoxy resin composition, characterized in that, The self-catalytically controllable curing epoxy resin composition includes an epoxy resin component and a curing agent component; The epoxy resin component comprises the following components in parts by weight: 50-70 parts of bisphenol A type epoxy resin; 25-45 parts of bisphenol F type epoxy resin; 10-20 parts of alicyclic epoxy resin; 5-10 parts of glycerol amine epoxy resin; 0.3-1.5 parts of defoamer; The curing agent component includes 90-110 parts by weight of an acid anhydride curing agent.

2. The self-catalytically curable epoxy resin composition according to claim 1, characterized in that, The bisphenol A type epoxy resin has a viscosity of 8000-13000 mPa·s at 23±2℃, an epoxy equivalent of 182-194 g / eq, and a chlorine content of ≤600 ppm. Preferably, the bisphenol A type epoxy resin has a viscosity of 9000-11000 mPa·s at 23±2℃, an epoxy equivalent of 184-192 g / eq, and a chlorine content of ≤500 ppm.

3. The self-catalytically curable epoxy resin composition according to claim 1 or 2, characterized in that, The bisphenol F type epoxy resin has a viscosity of 5000-9000 mPa·s at 23±2℃, an epoxy equivalent of 163-177 g / eq, and a chlorine content of ≤600 ppm. Preferably, the bisphenol F type epoxy resin has a viscosity of 6000-7500 mPa·s at 23±2℃, an epoxy equivalent of 165-175 g / eq, and a chlorine content of ≤500 ppm.

4. The self-catalytically curable epoxy resin composition according to any one of claims 1-3, characterized in that, The alicyclic epoxy resin has a viscosity of 180-600 mPa·s at 23±2℃, an epoxy equivalent of 125-150 g / eq, and a chlorine content of ≤500 ppm. Preferably, the alicyclic epoxy resin has a viscosity of 200-350 mPa·s at 23±2℃, an epoxy equivalent of 128-140 g / eq, and a chlorine content of ≤300 ppm.

5. The self-catalytically curable epoxy resin composition according to any one of claims 1-4, characterized in that, The glycerol amine epoxy resin has a viscosity of 3000-4500 mPa·s at 50°C and an epoxy equivalent of 100-130 g / eq. Preferably, the glycerol amine epoxy resin has a viscosity of 3300-3800 mPa·s at 50°C and an epoxy equivalent of 100-120 g / eq. Preferably, the glycerolamine epoxy resin is a multifunctional glycerolamine epoxy resin, and the functionality of the multifunctional glycerolamine epoxy resin is 3-4.

6. The self-catalytically curable epoxy resin composition according to any one of claims 1-5, characterized in that, The defoamer is a polymer-type defoamer; Preferably, the solid content of the defoamer is ≥99.8%.

7. The self-catalytically curable epoxy resin composition according to any one of claims 1-6, characterized in that, The anhydride curing agent includes methylhexahydrophthalic anhydride and / or methylnadic anhydride, preferably a combination of methylhexahydrophthalic anhydride and methylnadic anhydride; Preferably, the anhydride curing agent has a viscosity of 40-70 mPa·s at 23±2℃, a free acid content of ≤0.6%, and an iodine value of ≤1.5%. Preferably, the anhydride curing agent has a viscosity of 45-60 mPa·s at 23±2℃, a free acid content of ≤0.5%, and an iodine value of ≤1.4%.

8. A method for preparing a self-catalytically curable epoxy resin composition as described in any one of claims 1-7, characterized in that, The preparation method includes the following steps: Preparation of epoxy resin components: Bisphenol A type epoxy resin, bisphenol F type epoxy resin, alicyclic epoxy resin, glycerol amine epoxy resin and defoamer are mixed according to the formula to obtain the epoxy resin components; Preparation of curing agent components: Take the acid anhydride curing agent according to the formula to obtain the curing agent components; Preferably, the bisphenol A type epoxy resin, bisphenol F type epoxy resin and alicyclic epoxy resin further include a pretreatment step before mixing; Preferably, the pretreatment step includes mixing bisphenol A epoxy resin, bisphenol F epoxy resin and alicyclic epoxy resin, followed by purification and screening to obtain a light phase component; Preferably, the purification screening includes the steps of sequential thin-film evaporation and distillation; Preferably, the temperature at which the thin film evaporates is 180-190°C; Preferably, the distillation temperature is 210-240℃ and the vacuum degree is 50-200 Pa; Preferably, the preparation of the epoxy resin components further includes a vacuum treatment step after mixing; Preferably, the vacuum treatment temperature in the preparation of the epoxy resin component is 55-65℃, and the vacuum degree is 300-500Pa; Preferably, the vacuum treatment in the preparation of the epoxy resin component is carried out under stirring for 30-60 minutes; Preferably, the preparation of the curing agent component further includes vacuum treatment of the acid anhydride curing agent; Preferably, the vacuum degree of the vacuum treatment during the preparation of the curing agent component is 300-500 Pa; Preferably, the vacuum treatment in the preparation of the curing agent component is carried out under stirring for 30-60 minutes.

9. The application of a self-catalytically curable epoxy resin composition as described in any one of claims 1-7 in ultra-high voltage electrical insulation components.

10. A method of applying the self-catalytically curable epoxy resin composition as described in any one of claims 1-7, characterized in that, The application method includes mixing, vacuum casting, impregnation and curing the self-catalytically controllable curing epoxy resin composition according to any one of claims 1-7; Preferably, the mixing process includes vacuum degassing after mixing the epoxy resin component and the curing agent component; Preferably, the mass ratio of epoxy resin component to curing agent component in the mixed adhesive is 100:(90-110); Preferably, the mixing temperature in the adhesive mixture is 45-60℃ and the vacuum degree is 50-200 Pa; Preferably, the vacuum degassing temperature is 45-60℃ and the vacuum degree is 50-200 Pa; Preferably, the vacuum casting includes continuous casting for 5-10 days at 45-55℃ and 100-300 Pa; Preferably, the impregnation and curing include impregnation at 50-60℃ for 3-6 days, gel curing at 60-70℃ for 1-2 days, curing at 70-90℃ for 1-2 days, curing at 90-110℃ for 1-2 days, curing at 110-130℃ for 2-3 days, and curing at 130-80℃ for 3-5 days.

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