Epoxy insulation paste for ultralow-temperature environment and preparation method of epoxy insulation paste

Abstract

The invention discloses an epoxy insulation paste used in an ultralow temperature environment and a preparation method thereof, and belongs to the technical field of epoxy insulation paste. The epoxy insulating glue comprises a component A and a component B, the component A is prepared from the following components in parts by mass: 56 to 58 parts of epoxy resin, 17 to 19 parts of modified inorganic filler, 13 to 15 parts of organic silicon toughening agent, 3 to 4 parts of reactive diluent, 0.4 to 0.6 part of thixotropic agent and 0.3 to 0.5 part of wetting leveling agent; the component B is prepared from the following components in parts by mass: 6 to 10 parts of cyanate ester monomer, 2 to 4 parts of 4-methyl tetrahydrophthalic anhydride and 0.3 to 0.5 part of accelerant; the modified inorganic filler is hollow porous zirconium tungstate modified by a silane coupling agent; the organic silicon toughening agent is obtained by reacting triazine containing unsaturated bonds with tetramethyldisiloxane and then reacting with 1, 3-bis (3-aminopropyl)-1, 1, 3, 3-tetramethyldisiloxane and a silane ring body, and the organic silicon toughening agent is obtained by reacting triazine containing unsaturated bonds with the tetramethyldisiloxane and then reacting with the 1, 3-bis (3-aminopropyl)-1, 1, 3, 3-tetramethyldisiloxane and the silane ring body.

Description

Technical Field

[0001] The invention relates to an epoxy insulating adhesive for ultra-low temperature environment and a preparation method thereof. Background Art

[0002] With the continued expansion of extreme application scenarios such as aerospace, polar exploration, and superconducting technology, the performance requirements for materials in extreme environments are becoming increasingly stringent. In the fields of electronic packaging and structural bonding, epoxy resin is widely used as an insulating adhesive material due to its excellent electrical insulation, high mechanical strength, and good chemical resistance.

[0003] However, when in an ultra-low temperature environment (<-100°C), traditional bisphenol A epoxy resin-based insulating adhesives expose many performance defects, which seriously restrict their application in extreme low temperature scenarios. Among them, low-temperature embrittlement is the most critical problem. Under extremely low temperature conditions, the mobility of the resin molecular segments is greatly reduced, causing the overall flexibility of the material to deteriorate sharply, showing significant brittle behavior. Taking conventional epoxy adhesive as an example, at liquid nitrogen temperature (-196°C), its shear strength may decay by more than 50%, which has a great negative impact on the structural stability and reliability of the material in low temperature environments, thereby shortening the service life of epoxy resin in ultra-low temperature environments.

[0004] Since traditional epoxy insulating adhesives have these performance shortcomings in ultra-low temperature environments, in order to meet the material requirements of extreme application scenarios, it is urgent to develop an epoxy insulating adhesive that can be used stably for a long time in ultra-low temperature environments. Based on this, the applicant is committed to researching and preparing an epoxy insulating adhesive that is resistant to ultra-low temperature environments to solve the problem of short service life of traditional epoxy resins in ultra-low temperature environments. Summary of the Invention

[0005] The purpose of the present invention is to provide an epoxy insulating adhesive for ultra-low temperature environment and a preparation method thereof, so as to solve the technical problems mentioned in the above background technology.

[0006] The technical solution for achieving the purpose of the present invention is:

[0007] In the first aspect, the present invention provides an epoxy insulating adhesive for ultra-low temperature environments, comprising component A and component B, wherein the raw materials of component A include, by mass, 56 to 58 parts of epoxy resin, 17 to 19 parts of modified inorganic filler, 13 to 15 parts of silicone toughening agent, 3 to 4 parts of active diluent, 0.4 to 0.6 parts of thixotropic agent, and 0.3 to 0.5 parts of wetting and leveling agent; the raw materials of component B include, by mass, 6 to 10 parts of cyanate monomer, 2 to 4 parts of 4-methyltetrahydrophthalic anhydride, and 0.3 to 0.5 parts of accelerator.

[0008] The epoxy resin includes any one or a combination of at least two of bisphenol A epoxy resin YL980, hydrogenated bisphenol A epoxy resin YX-8000D, alicyclic epoxy resin celloxide 2021P, alicyclic epoxy resin Epolead GT401, alicyclic epoxy resin S-28, and triglycidyl p-aminophenol.

[0009] The active diluent is 4-butanediol diglycidyl ether;

[0010] The wetting and leveling agent is BYK-333;

[0011] The thixotropic agent is fumed silica;

[0012] The accelerator is one or more of 2-ethyl-4-methylimidazole, 2-phenylimidazole, and 2-phenyl-4-ethylimidazole.

[0013] Furthermore, the modified inorganic filler is a hollow porous zirconium tungstate modified by a silane coupling agent; the silane coupling agent is obtained by combining tridecafluorooctyltriethoxysilane and 3-mercaptopropyltrimethoxysilane in a molar ratio of 1:2 to 4.

[0014] Furthermore, the organosilicon toughening agent is obtained by first reacting a triazine containing an unsaturated bond with tetramethyldisiloxane and then reacting with 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane and a silane ring body; the silane ring is a combination of trimethyltris(trifluoropropyl)cyclotrisiloxane and any one of trimethyltrivinylcyclotrisiloxane and tetramethyltetravinylcyclotetrasiloxane; preferably, the silane ring is obtained by mixing trimethyltris(trifluoropropyl)cyclotrisiloxane and tetramethyltetravinylcyclotetrasiloxane in a molar ratio of 1:0.8 to 1.

[0015] Furthermore, the triazine containing an unsaturated bond is synthesized by oxidative ring-closure of 5-ethynyl-2-hydroxybenzaldehyde and 4-[(amidinothio)methyl]styrene hydrochloride under the catalysis of copper acetate monohydrate.

[0016] Furthermore, the cyanate monomer is obtained by reacting 5,6,11,12-tetrahydrodibenzo[a,e][8]annulene-2,9-dicarboxylic acid with 4-methoxymethylaniline, followed by reacting with o-cresol, and finally performing a cyanate esterification reaction.

[0017] In a second aspect, the present invention further provides a method for preparing the epoxy insulating adhesive for ultra-low temperature environments described in the first aspect, comprising the following preparation steps:

[0018] (1) Weigh each raw material component according to its own mass fraction;

[0019] (2) Under nitrogen protection, the epoxy resin and silicone toughening agent weighed in step (1) are mixed and stirred at high speed shear for 25 to 35 minutes, stirred at 48 to 52° C. for 18 to 22 minutes, and then the modified inorganic filler and the photoinitiator with a mass of 0.004 to 0.006 times of the modified inorganic filler are added and continued to stir for 55 to 65 minutes, followed by ultrasonic dispersion for 55 to 65 minutes, and continued to be irradiated with a UV-LED point light source with a wavelength of 365 nm for 1 to 2 hours under stirring conditions, and then the reactive diluent, thixotropic agent, and wetting and leveling agent are added and fully mixed, and packaged for use to obtain component A;

[0020] (3) The cyanate monomer, 4-methyltetrahydrophthalic anhydride and accelerator weighed in step (1) are fully mixed and packaged for later use to obtain component B.

[0021] (4) Separately packing one portion of component A obtained in step (2) and one portion of component B obtained in step (3) to form a group of epoxy insulating adhesive for ultra-low temperature environments.

[0022] Furthermore, the preparation method of the modified inorganic filler is as follows: the hollow porous zirconium tungstate is added to a 90wt% ethanol aqueous solution with a mass of 100 times that of the hollow porous zirconium tungstate, and ultrasonically dispersed to obtain a dispersion A; 0.06 to 0.08 times the mass of the hollow porous zirconium tungstate is added to a silane coupling agent with a mass of 100 times that of the hollow porous zirconium tungstate, and the mixture is allowed to stand for 115 to 125 minutes, then added to the dispersion A and stirred for 25 to 35 minutes, ultrasonically dispersed for 4 to 6 minutes, and then centrifuged and washed 3 times with ethanol in a centrifuge, and then dried to obtain a modified inorganic filler.

[0023] Furthermore, the preparation steps of the organosilicon toughening agent are as follows:

[0024] A1. 100 parts by mass of an unsaturated triazine was mixed with 4.5 to 5 parts by mass of a Custer catalyst, and then the temperature was raised to 75 to 85°C. 350 to 400 parts by mass of tetramethyldisiloxane was then added dropwise at a rate of 1 to 3 seconds. After the addition was complete, the reaction was continued for 5.5 to 6.5 hours, followed by vacuum distillation to obtain triazinyltetramethyldisiloxane.

[0025] The reaction steps of triazine tetramethyl disiloxane are as follows:

[0026]

[0027] A2. 14-16 parts by mass of triazinyltetramethyldisiloxane, 500 parts by mass of tetramethyltetravinylcyclotetrasiloxane, and 0.9-1.1 parts by mass of trifluoromethanesulfonic acid were mixed, followed by reaction at 80±5°C for 5.5-6.5 hours. Subsequently, 4-6 parts by mass of 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane were added and the reaction was continued for 5.5-6.5 hours. 1.8-2.2 parts by mass of calcium carbonate were then added to neutralize the trifluoromethanesulfonic acid. The mixture was then filtered and distilled under reduced pressure to remove unreacted siloxane rings and small molecular weight siloxanes. The mixture was naturally cooled to room temperature to obtain an organosilicon toughening agent.

[0028] Furthermore, the preparation method of the triazine containing an unsaturated bond is as follows: 5-ethynyl-2-hydroxybenzaldehyde, 4-[(amidinothio)methyl]styrene hydrochloride, sodium carbonate, copper acetate monohydrate, and toluene are mixed and refluxed for 23.5 to 24.5 hours, then cooled to room temperature, added with water to azeotropically distill off the toluene, boiled with water three times, and then purified by silica gel column chromatography using petroleum ether and ethyl acetate in a volume ratio of 100:1 to obtain the triazine containing an unsaturated bond; wherein the molar ratio of 5-ethynyl-2-hydroxybenzaldehyde, 4-[(amidinothio)methyl]styrene hydrochloride, sodium carbonate, and copper acetate monohydrate is (6.75 to 6.85):(11.35 to 11.45):(11.35 to 11.45):(2.9 to 3.0); the mass of toluene is 17 to 18 times the mass of 5-ethynyl-2-hydroxybenzaldehyde;

[0029] The reaction route of triazine containing unsaturated bonds is as follows:

[0030]

[0031] Furthermore, the preparation method of the cyanate ester monomer is as follows:

[0032] B1. 148-149 parts by mass of 5,6,11,12-tetrahydrodibenzo[a,e][8]annulene-2,9-dicarboxylic acid, 137-138 parts by mass of 4-methoxymethylaniline, 1.17-1.19 parts by mass of triphenyl phosphite, 3.07-3.09 parts by mass of N-methylpyrrolidone, 0.58-0.6 parts by mass of pyridine, and 298-302 parts by mass of calcium chloride were stirred and mixed, followed by reaction at 115-125°C under vacuum conditions for 9.5-10.5 hours. After cooling to room temperature, the mixture was poured into 200 parts by mass of methanol to form a precipitate. The mixture was then washed three times with methanol and distilled water at 70-90°C, filtered, and dried under vacuum to obtain an intermediate product A.

[0033] B2. 215-217 parts by mass of o-cresol and 4.31-4.33 parts by mass of p-toluenesulfonic acid were mixed, then heated to 80 ° C and stirred to mix uniformly, then heated to 130 ° C, 46-46.2 parts by mass of intermediate product A were added within 55-65 min, and then kept warm for 4.5-5.5 h, then cooled to 80-90 ° C, and sodium hydroxide aqueous solution was added dropwise to neutralize the p-toluenesulfonic acid in the reaction system, followed by vacuum distillation to remove unreacted o-cresol, then dissolved in boiling toluene and washed three times with 70-80 ° C distilled water, the toluene layer obtained after washing was cooled to -18 ° C, then filtered, recrystallized, and vacuum dried to obtain intermediate product B;

[0034] B3. 200 parts by mass of dichloromethane and 42.6 to 42.8 parts by mass of cyanogen chloride were mixed, and then cooled to -5°C. Under nitrogen protection, a mixture of 95 to 105 parts by mass of the intermediate product B, 90 to 92 parts by mass of triethylamine, and 200 parts by mass of butanone was added within 35 to 45 minutes. The reaction temperature was controlled at -5 to 0°C, and the reaction was kept warm for 2 hours. After the reaction was completed, the generated triethylamine salt was removed by washing with water, followed by acid washing, alkali washing, water washing, and layering to obtain an organic phase, which was then dried over anhydrous sodium sulfate and then distilled under reduced pressure to remove dichloromethane to obtain a cyanate monomer.

[0035] The specific reaction route is as follows:

[0036]

[0037] By adopting the above technical solution, the present invention has the following beneficial effects:

[0038] (1) The present invention provides an epoxy insulating adhesive for ultra-low temperature environments, comprising component A and component B, wherein the raw material components of component A include, by weight, 56 to 58 parts of epoxy resin, 17 to 19 parts of modified inorganic filler, 13 to 15 parts of organosilicon toughening agent, 3 to 4 parts of active diluent, 0.4 to 0.6 parts of thixotropic agent, and 0.3 to 0.5 parts of wetting and leveling agent; the raw material components of component B include, by weight, 6 to 10 parts of cyanate ester monomer, 2 to 4 parts of 4-methyltetrahydrophthalic anhydride, and 0.3 to 0.5 parts of accelerator; by introducing modified inorganic filler, organosilicon toughening agent, and cyanate ester monomer, the low-temperature resistance of the epoxy insulating adhesive for ultra-low temperature environments can be effectively improved, thereby improving the service life of the epoxy insulating adhesive for ultra-low temperature environments in ultra-low temperature environments.

[0039] (2) The organosilicon toughening agent used in the epoxy insulating adhesive for ultra-low temperature environment of the present invention is obtained by first reacting a triazine containing an unsaturated bond with tetramethyldisiloxane through an unsaturated olefin bond and an alkyne bond with the silicon-hydrogen bond of tetramethyldisiloxane, and then reacting with 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane and a silane ring body. The organosilicon toughening agent with a hyperbranched structure using a triazine containing an unsaturated bond as a branching unit and a polysiloxane molecular chain as a linear unit is introduced into the epoxy insulating adhesive to have good flexibility and a wide temperature range. While maintaining a stable comprehensive performance of the polysiloxane molecular chain within a certain range, a branched structure of epoxy insulating adhesive is formed, and a cavity is formed in the epoxy insulating adhesive, which can effectively improve the low-temperature resistance of the epoxy insulating adhesive; wherein, the silane ring is a combination of trimethyltri(trifluoropropyl)cyclotrisiloxane and any one of trimethyltrivinylcyclotrisiloxane and tetramethyltetravinylcyclotetrasiloxane; preferably, the silane ring is obtained by combining trimethyltri(trifluoropropyl)cyclotrisiloxane and tetramethyltetravinylcyclotetrasiloxane, and an olefin bond is introduced into the cavity of the epoxy insulating adhesive.

[0040] (3) The triazine containing an unsaturated bond of the present invention is synthesized by oxidative ring-closure of 5-ethynyl-2-hydroxybenzaldehyde and 4-[(amidinothio)methyl]styrene hydrochloride under the catalytic action of copper acetate monohydrate, and phenol is introduced at the ortho position of the triazine ring. The hydroxyl group on the phenol and the ortho position of the triazine ring can form an intramolecular hydrogen bond with the nitrogen atom on the triazine ring to form a six-membered chelate ring. After ultraviolet light irradiation, the electrons jump from the ground state to the first excited state, thermal vibration occurs, resulting in the breaking of the hydrogen bond and the opening of the chelate ring, forming a high-energy unstable ionic compound in the excited state. To return to the original low-energy stable state of the ground state, The excess energy is released through heat and other harmless forms of radiation energy, the chelate ring closes again, and the hydrogen bond is formed again. This process is reversible. During this process, ultraviolet light is absorbed to achieve an anti-ultraviolet effect. The silicone toughening agent used in epoxy insulation adhesive for ultra-low temperature environment is made of triazine containing unsaturated bonds, which first reacts with tetramethyldisiloxane through unsaturated olefin bonds and alkyne bonds with the silicon-hydrogen bond of tetramethyldisiloxane, and then reacts with 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane and silane ring body to effectively improve the anti-ultraviolet performance of epoxy insulation adhesive.

[0041] (4) The cyanate ester of the present invention is obtained by reacting 5,6,11,12-tetrahydrodibenzo[a,e][8]annulene-2,9-dicarboxylic acid with 4-methoxymethylaniline and then reacting with o-cresol, and finally performing a cyanate esterification reaction. Due to the good dielectric properties, mechanical properties, heat resistance and radiation resistance of the cyanate ester, by introducing the cyanate ester and the epoxy material during the curing process, the cyanate ester first self-polymerizes into a dimer, and further copolymerizes to form a triazine ring. In this process, the epoxy group undergoes a polyether reaction, and finally the triazine ring reacts with the remaining epoxy group to form an oxazolidinone, which can effectively improve the radiation resistance of the epoxy insulation adhesive. At the same time, 5,6,11,12-tetrahydrodibenzo[a,e][8]annulene has good negative expansion characteristics, which can effectively reduce the expansion coefficient of the epoxy insulation adhesive, thereby reducing the thermal stress of the epoxy insulation adhesive, and further improving the low-temperature resistance of the epoxy insulation adhesive.

[0042] (5) The modified inorganic filler of the present invention is a hollow porous zirconium tungstate modified by a silane coupling agent, wherein the silane coupling agent is obtained by mixing tridecafluorooctyltriethoxysilane and 3-mercaptopropyltrimethoxysilane; it can effectively increase the dispersibility of the hollow porous zirconium tungstate in the epoxy insulation adhesive. While ensuring the dispersibility of the epoxy insulation adhesive, the hollow porous zirconium tungstate is introduced into the epoxy insulation adhesive. On the one hand, the introduction of zirconium tungstate can prevent crack propagation and enhance fracture energy during load-bearing, effectively increasing the toughness of the epoxy resin. At the same time, zirconium tungstate is a typical negative expansion filler. The introduction of zirconium tungstate can effectively reduce the expansion coefficient of the epoxy insulation adhesive, thereby reducing the thermal stress of the epoxy insulation adhesive, and further improving the low-temperature resistance of the epoxy insulation adhesive.

[0043] (6) After the epoxy resin and the organosilicon toughening agent are mixed, the present invention can form an epoxy resin base material system with a hyperbranched structure, form a cavity containing an olefin bond in the epoxy resin base material, and then introduce a modified inorganic filler. While the modified inorganic filler is dispersed into the cavity, the thiol group on the modified inorganic filler and the olefin bond on the inner wall of the cavity undergo a click reaction and grafting under the action of a photoinitiator, thereby further ensuring the mechanical properties of the epoxy insulating adhesive. When component A is mixed with component B, the cyanate monomer and 4-methyltetrahydrophthalic anhydride of component B are dispersed into the epoxy system of component A and the pores of the modified inorganic filler and react with the unreacted epoxy resin. The obtained polymer molecular chains shuttle through the pores of the inorganic filler and cross-link with the molecular chains of the epoxy resin base material to form an interpenetrating network structure, which can further enhance the toughness of the epoxy insulating adhesive. DETAILED DESCRIPTION

[0044] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with specific implementation methods.

[0045] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative work shall fall within the scope of protection of the present invention.

[0046] The following examples are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0047] Some of the raw materials of some embodiments and comparative examples of the present invention are as follows:

[0048] The epoxy resin base material is obtained by mixing triglycidyl p-aminophenol and Daicel's alicyclic epoxy resin Epolead GT401 in a mass ratio of 5:1.

[0049] CAS number of 5,6,11,12-tetrahydrodibenzo[a,e][8]annulene-2,9-dicarboxylic acid is: 2170730-09-1

[0050] The particle size D50 of hollow mesoporous zirconium tungstate is 10 μm, and the pore size is about 500 nm. The detailed preparation steps can be found in the following literature: [1] Zhang Yifan. Research on the preparation process of porous zirconium tungstate powder [D]. Harbin Institute of Technology, 2022. DOI: 10.27061 / d.cnki.ghgdu.2022.004306.

[0051] The cyanate ester used was 1,1-bis(4-cyanophenyl)ethane, which was provided by Chengdu Yuanda Chemical Company.

[0052] The photoinitiator used was benzil dimethyl ether.

[0053] The active diluent is 4-butanediol diglycidyl ether;

[0054] The wetting and leveling agent is BYK-333;

[0055] The thixotropic agent is fumed silica;

[0056] The accelerator is 2-ethyl-4-methylimidazole.

[0057] (Example 1)

[0058] A method for preparing epoxy insulating adhesive for ultra-low temperature environments comprises the following steps:

[0059] (1) Weighing and preparing the raw material components according to their respective mass parts; including component A and component B, the raw material components of component A, calculated by mass parts, include 56 mass parts of epoxy resin, 17 mass parts of modified inorganic filler, 13 mass parts of organosilicon toughening agent, 3 mass parts of reactive diluent, 0.4 mass parts of thixotropic agent, and 0.3 mass parts of wetting and leveling agent; the raw material components of component B, calculated by mass parts, include 6 mass parts of cyanate monomer, 4 mass parts of 4-methyltetrahydrophthalic anhydride, and 0.3 mass parts of accelerator;

[0060] (2) Under nitrogen protection, the epoxy resin and silicone toughening agent weighed in step (1) are mixed and stirred at high speed shear for 25 to 35 minutes, stirred at 48 to 52° C. for 18 to 22 minutes, and then the modified inorganic filler and the photoinitiator with a mass of 0.004 to 0.006 times of the modified inorganic filler are added and continued to stir for 55 to 65 minutes, followed by ultrasonic dispersion for 55 to 65 minutes, and continued to be irradiated with a UV-LED point light source with a wavelength of 365 nm for 1 to 2 hours under stirring conditions, and then the reactive diluent, thixotropic agent, and wetting and leveling agent are added and fully mixed, and packaged for use to obtain component A;

[0061] (3) The cyanate monomer, 4-methyltetrahydrophthalic anhydride and accelerator weighed in step (1) are fully mixed and packaged for later use to obtain component B.

[0062] (4) Separately packaging one portion of component A obtained in step (2) and one portion of component B obtained in step (3) to form a set of epoxy insulating adhesive for ultra-low temperature environments;

[0063] (5) Fully mix one package of component A and one package of component B, raise the temperature to 58°C and continue stirring for 25 minutes to obtain epoxy insulation adhesive for ultra-low temperature environment.

[0064] The modified inorganic filler is prepared as follows: adding the hollow porous zirconium tungstate to a 90wt% ethanol aqueous solution with a mass of 100 times that of the hollow porous zirconium tungstate and ultrasonically dispersing the mixture to obtain a dispersion A; adding a silane coupling agent with a mass of 0.06 times that of the hollow porous zirconium tungstate to ethanol with a mass of 100 times that of the hollow porous zirconium tungstate, mixing the mixture, leaving it to stand for 115 minutes, adding it to the dispersion A, stirring it for 25 minutes, ultrasonically dispersing it for 4 minutes, and then centrifugally washing it with ethanol three times in a centrifuge, and then drying it to obtain the modified inorganic filler; the silane coupling agent is obtained by combining tridecafluorooctyltriethoxysilane and 3-mercaptopropyltrimethoxysilane in a molar ratio of 1:3.

[0065] The preparation steps of the organosilicon toughening agent are as follows:

[0066] A1. 100 parts by mass of an unsaturated triazine was mixed with 4.5 parts by mass of a Custer catalyst, and then the temperature was raised to 75°C. 350 parts by mass of tetramethyldisiloxane was then added dropwise at a rate of 1 second. After the addition was complete, the reaction was continued for 5.5 hours, followed by vacuum distillation to obtain triazinyltetramethyldisiloxane.

[0067] A2. 14 parts by mass of triazinetetramethyldisiloxane, 500 parts by mass of tetramethyltetravinylcyclotetrasiloxane, and 0.9 parts by mass of trifluoromethanesulfonic acid were mixed and then reacted at 80°C for 5.5 hours. Subsequently, 4 parts by mass of 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane were added and the reaction was continued for 5.5 hours. Then, 1.8 parts by mass of calcium carbonate was added to neutralize the trifluoromethanesulfonic acid. The mixture was then filtered and distilled under reduced pressure to remove unreacted siloxane rings and small molecular weight siloxanes. The mixture was naturally cooled to room temperature to obtain a silicone toughening agent.

[0068] The silane ring is obtained by mixing trimethyltris(trifluoropropyl)cyclotrisiloxane and tetramethyltetravinylcyclotetrasiloxane in a molar ratio of 1:1.

[0069] The preparation method of the triazine containing an unsaturated bond is as follows: 5-vinyl-2-hydroxybenzaldehyde, 4-[(amidinothio)methyl]styrene hydrochloride, sodium carbonate, copper acetate monohydrate, and toluene are mixed and refluxed for 23.5 hours, then cooled to room temperature, added with water for azeotropic distillation of toluene, boiled with water three times, and then purified by silica gel column chromatography using petroleum ether and ethyl acetate in a volume ratio of 100:1 to obtain the triazine containing an unsaturated bond. The molar ratio of 5-vinyl-2-hydroxybenzaldehyde, 4-[(amidinothio)methyl]styrene hydrochloride, sodium carbonate, and copper acetate monohydrate is 6.75:11.35:11.35:2.9; and the mass of toluene is 17 times the mass of 5-vinyl-2-hydroxybenzaldehyde.

[0070] The preparation method of the cyanate ester monomer is as follows:

[0071] B1. 148 parts by mass of 5,6,11,12-tetrahydrodibenzo[a,e][8]annulene-2,9-dicarboxylic acid, 137 parts by mass of 4-methoxymethylaniline, 1.17 parts by mass of triphenyl phosphite, 3.07 parts by mass of N-methylpyrrolidone, 0.58 parts by mass of pyridine, and 298 parts by mass of calcium chloride were stirred and mixed, followed by reaction at 115°C for 9.5 hours under vacuum conditions. After cooling to room temperature, the mixture was poured into 200 parts by mass of methanol to form a precipitate, which was then washed three times with methanol and 70°C distilled water, filtered, and vacuum dried to obtain intermediate product A.

[0072] B2. 215 parts by mass of o-cresol and 4.31 parts by mass of p-toluenesulfonic acid were mixed and then heated to 80°C with stirring to mix evenly. The temperature was then raised to 130°C and 46 parts by mass of intermediate product A were added within 55 minutes. The mixture was then kept warm for 4.5 hours and then cooled to 80°C. An aqueous sodium hydroxide solution was added dropwise to neutralize the p-toluenesulfonic acid in the reaction system. Unreacted o-cresol was then removed by distillation under reduced pressure. The mixture was then dissolved in boiling toluene and washed three times with 70°C distilled water. The toluene layer obtained after washing was cooled to -18°C, then filtered, recrystallized, and vacuum dried to obtain intermediate product B.

[0073] B3. Mix 200 parts by mass of dichloromethane and 42.6 parts by mass of cyanogen chloride, then cool to -5°C, and add a mixture obtained by mixing 95 parts by mass of intermediate product B, 90 parts by mass of triethylamine, and 200 parts by mass of butanone under nitrogen protection within 35 minutes. The reaction temperature is controlled at -5°C and kept warm for 2 hours. After the reaction is completed, the generated triethylamine salt is removed by washing with water, followed by acid washing, alkali washing, water washing, and layering to obtain an organic phase, which is then dried over anhydrous sodium sulfate and then distilled under reduced pressure to remove dichloromethane to obtain a cyanate ester monomer.

[0074] (Example 2)

[0075] A method for preparing epoxy insulating adhesive for ultra-low temperature environments comprises the following steps:

[0076] (1) Weighing and preparing the raw material components according to their respective mass parts; including component A and component B, the raw material components of component A, calculated by mass parts, include 57 mass parts of epoxy resin, 18 mass parts of modified inorganic filler, 14 mass parts of organosilicon toughening agent, 3.5 mass parts of reactive diluent, 0.5 mass parts of thixotropic agent, and 0.4 mass parts of wetting and leveling agent; the raw material components of component B, calculated by mass parts, include 8 mass parts of cyanate monomer, 3 mass parts of 4-methyltetrahydrophthalic anhydride, and 0.4 mass parts of accelerator;

[0077] (2) Under nitrogen protection, the epoxy resin and silicone toughening agent weighed in step (1) were mixed and stirred at high speed shear for 30 minutes, stirred at 50° C. for 20 minutes, and then the modified inorganic filler and the photoinitiator with a mass of 0.005 times that of the modified inorganic filler were added and continued to stir for 60 minutes, followed by ultrasonic dispersion for 60 minutes, and continued to be irradiated with a UV-LED point light source with a wavelength of 365 nm for 1.5 hours under stirring conditions, and then the active diluent, thixotropic agent, and wetting and leveling agent were added and fully mixed, and packaged for use to obtain component A;

[0078] (3) The cyanate monomer, 4-methyltetrahydrophthalic anhydride and accelerator weighed in step (1) are fully mixed and packaged for later use to obtain component B.

[0079] (4) Separately packaging one portion of component A obtained in step (2) and one portion of component B obtained in step (3) to form a set of epoxy insulating adhesive for ultra-low temperature environments;

[0080] (5) Fully mix one package of component A and one package of component B, raise the temperature to 58°C and continue stirring for 25 minutes to obtain epoxy insulation adhesive for ultra-low temperature environment.

[0081] The modified inorganic filler is prepared as follows: adding hollow porous zirconium tungstate to a 90wt% ethanol aqueous solution with a mass of 100 times that of the hollow porous zirconium tungstate and ultrasonically dispersing the mixture to obtain a dispersion A; adding a silane coupling agent with a mass of 0.07 times that of the hollow porous zirconium tungstate to ethanol with a mass of 100 times that of the hollow porous zirconium tungstate, mixing the mixture, leaving it to stand for 120 minutes, adding it to the dispersion A and stirring for 30 minutes, ultrasonically dispersing it for 5 minutes, then centrifugally washing it with ethanol three times in a centrifuge, and then drying it to obtain the modified inorganic filler; the silane coupling agent is obtained by combining tridecafluorooctyltriethoxysilane and 3-mercaptopropyltrimethoxysilane in a molar ratio of 1:3.

[0082] The preparation steps of the organosilicon toughening agent are as follows:

[0083] A1. 100 parts by mass of an unsaturated triazine was mixed with 4.8 parts by mass of a Custer catalyst, and then the temperature was raised to 80°C. 380 parts by mass of tetramethyldisiloxane was then added dropwise at a rate of 2 seconds. After the addition was complete, the reaction was continued for 6 hours, followed by vacuum distillation to obtain triazinyltetramethyldisiloxane.

[0084] A2. 15 parts by mass of triazine tetramethyldisiloxane, 500 parts by mass of tetramethyltetravinylcyclotetrasiloxane, and 1 part by mass of trifluoromethanesulfonic acid were mixed and reacted at 82°C for 6 hours. 5 parts by mass of 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane were then added and the reaction continued for 6 hours. 2 parts by mass of calcium carbonate were then added to neutralize the trifluoromethanesulfonic acid. The mixture was then filtered and distilled under reduced pressure to remove unreacted siloxane rings and small molecule siloxanes. The mixture was then naturally cooled to room temperature to obtain a silicone toughening agent.

[0085] The silane ring is obtained by mixing trimethyltris(trifluoropropyl)cyclotrisiloxane and tetramethyltetravinylcyclotetrasiloxane in a molar ratio of 1:1.

[0086] The preparation method of the triazine containing an unsaturated bond is as follows: 5-vinyl-2-hydroxybenzaldehyde, 4-[(amidinothio)methyl]styrene hydrochloride, sodium carbonate, copper acetate monohydrate, and toluene are mixed and refluxed for reaction for 24 hours, then cooled to room temperature, added with water for azeotropic distillation of toluene, boiled with water three times, and then purified by silica gel column chromatography using petroleum ether and ethyl acetate in a volume ratio of 100:1 to obtain the triazine containing an unsaturated bond. The molar ratio of 5-vinyl-2-hydroxybenzaldehyde, 4-[(amidinothio)methyl]styrene hydrochloride, sodium carbonate, and copper acetate monohydrate is 6.8:11.4:11.4:2.95; and the mass of toluene is 17.5 times the mass of 5-vinyl-2-hydroxybenzaldehyde.

[0087] The preparation method of the cyanate ester monomer is as follows:

[0088] B1. 148.2 parts by mass of 5,6,11,12-tetrahydrodibenzo[a,e][8]annulene-2,9-dicarboxylic acid, 137.5 parts by mass of 4-methoxymethylaniline, 1.18 parts by mass of triphenyl phosphite, 3.08 parts by mass of N-methylpyrrolidone, 0.59 parts by mass of pyridine, and 300 parts by mass of calcium chloride were stirred and mixed, followed by reaction at 120°C for 10 h under vacuum conditions. After cooling to room temperature, the mixture was poured into 200 parts by mass of methanol to form a precipitate, which was then washed three times with methanol and 80°C distilled water, filtered, and vacuum-dried to obtain intermediate product A.

[0089] B2. 216 parts by mass of o-cresol and 4.32 parts by mass of p-toluenesulfonic acid were mixed and then heated to 80°C with stirring to mix evenly. The temperature was then raised to 130°C and 46.1 parts by mass of intermediate product A were added over 60 minutes. The reaction was then kept warm for 5 hours and then cooled to 85°C. An aqueous sodium hydroxide solution was added dropwise to neutralize the p-toluenesulfonic acid in the reaction system. Unreacted o-cresol was then removed by distillation under reduced pressure. The mixture was then dissolved in boiling toluene and washed three times with 75°C distilled water. The toluene layer obtained after washing was cooled to -18°C, filtered, recrystallized, and vacuum dried to obtain intermediate product B.

[0090] B3. 200 parts by mass of dichloromethane and 42.7 parts by mass of cyanogen chloride were mixed, and then cooled to -5°C. Under nitrogen protection, a mixture of 100 parts by mass of intermediate product B, 91 parts by mass of triethylamine, and 200 parts by mass of butanone was added within 40 minutes. The reaction temperature was controlled at -2°C and kept warm for 2 hours. After the reaction, the generated triethylamine salt was removed by washing with water, followed by acid washing, alkali washing, water washing, and layering to obtain an organic phase, which was then dried over anhydrous sodium sulfate and then distilled under reduced pressure to remove dichloromethane to obtain a cyanate monomer.

[0091] (Example 3)

[0092] A method for preparing epoxy insulating adhesive for ultra-low temperature environments comprises the following steps:

[0093] (1) Weighing and preparing each raw material component according to their respective mass parts; including component A and component B, the raw material components of component A, calculated by mass parts, include 58 mass parts of epoxy resin, 19 mass parts of modified inorganic filler, 15 mass parts of organosilicon toughening agent, 4 mass parts of reactive diluent, 0.6 mass parts of thixotropic agent, and 0.5 mass parts of wetting and leveling agent; the raw material components of component B, calculated by mass parts, include 10 mass parts of cyanate monomer, 2 mass parts of 4-methyltetrahydrophthalic anhydride, and 0.5 mass parts of accelerator;

[0094] (2) Under nitrogen protection, the epoxy resin and silicone toughening agent weighed in step (1) were mixed and stirred at high speed shear for 35 minutes, stirred at 52° C. for 22 minutes, and then the modified inorganic filler and the photoinitiator with a mass of 0.006 times that of the modified inorganic filler were added and continued to stir for 65 minutes, followed by ultrasonic dispersion for 65 minutes, and continued to be irradiated with a UV-LED point light source with a wavelength of 365 nm for 2 hours under stirring conditions, and then the active diluent, thixotropic agent, and wetting and leveling agent were added and fully mixed, and packaged for use to obtain component A;

[0095] (3) The cyanate monomer, 4-methyltetrahydrophthalic anhydride and accelerator weighed in step (1) are fully mixed and packaged for later use to obtain component B.

[0096] (4) Separately packaging one portion of component A obtained in step (2) and one portion of component B obtained in step (3) to form a set of epoxy insulating adhesive for ultra-low temperature environments;

[0097] (5) Fully mix one package of component A and one package of component B, raise the temperature to 58°C and continue stirring for 25 minutes to obtain epoxy insulation adhesive for ultra-low temperature environment.

[0098] The preparation method of the modified inorganic filler is as follows: adding hollow porous zirconium tungstate to a 90wt% ethanol aqueous solution with a mass of 100 times that of the hollow porous zirconium tungstate and ultrasonically dispersing it to obtain dispersion A; adding a silane coupling agent with a mass of 0.08 times that of the hollow porous zirconium tungstate to ethanol with a mass of 100 times that of the hollow porous zirconium tungstate, mixing, standing for 125 minutes, adding it to the dispersion A and stirring for 35 minutes, ultrasonically dispersing it for 6 minutes, then centrifugally washing it with ethanol in a centrifuge three times, and then drying it to obtain the modified inorganic filler; the silane coupling agent is obtained by combining tridecafluorooctyltriethoxysilane and 3-mercaptopropyltrimethoxysilane in a molar ratio of 1:3.

[0099] The preparation steps of the organosilicon toughening agent are as follows:

[0100] A1. 100 parts by mass of an unsaturated triazine was mixed with 5 parts by mass of a Custer catalyst, and then the temperature was raised to 85°C. 400 parts by mass of tetramethyldisiloxane was then added dropwise at a rate of 3 seconds per drop. After the addition was complete, the reaction was continued for 6.5 hours, followed by vacuum distillation to obtain triazinyltetramethyldisiloxane.

[0101] A2. 16 parts by mass of triazinetetramethyldisiloxane, 500 parts by mass of tetramethyltetravinylcyclotetrasiloxane, and 1.1 parts by mass of trifluoromethanesulfonic acid were mixed and reacted at 78°C for 6.5 hours. Subsequently, 6 parts by mass of 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane were added and the reaction continued for 6.5 hours. Then, 2.2 parts by mass of calcium carbonate were added to neutralize the trifluoromethanesulfonic acid. The mixture was then filtered and distilled under reduced pressure to remove unreacted siloxane rings and small molecular weight siloxanes. The mixture was naturally cooled to room temperature to obtain a silicone toughening agent.

[0102] The silane ring is obtained by mixing trimethyltris(trifluoropropyl)cyclotrisiloxane and tetramethyltetravinylcyclotetrasiloxane in a molar ratio of 1:1.

[0103] The preparation method of the triazine containing an unsaturated bond is as follows: 5-vinyl-2-hydroxybenzaldehyde, 4-[(amidinothio)methyl]styrene hydrochloride, sodium carbonate, copper acetate monohydrate, and toluene are mixed and refluxed for 24.5 hours, then cooled to room temperature, added with water to azeotropically distill off the toluene, boiled with water three times, and then purified by silica gel column chromatography using petroleum ether and ethyl acetate in a volume ratio of 100:1 to obtain the triazine containing an unsaturated bond. The molar ratio of 5-vinyl-2-hydroxybenzaldehyde, 4-[(amidinothio)methyl]styrene hydrochloride, sodium carbonate, and copper acetate monohydrate is 6.85:11.45:11.45:3.0, and the mass of toluene is 18 times the mass of 5-vinyl-2-hydroxybenzaldehyde.

[0104] The preparation method of the cyanate ester monomer is as follows:

[0105] B1. 149 parts by mass of 5,6,11,12-tetrahydrodibenzo[a,e][8]annulene-2,9-dicarboxylic acid, 138 parts by mass of 4-methoxymethylaniline, 1.19 parts by mass of triphenyl phosphite, 3.09 parts by mass of N-methylpyrrolidone, 0.6 parts by mass of pyridine, and 302 parts by mass of calcium chloride were stirred and mixed, followed by reaction at 125°C for 10.5 hours under vacuum conditions. After cooling to room temperature, the mixture was poured into 200 parts by mass of methanol to form a precipitate, which was then washed three times with methanol and 90°C distilled water, filtered, and vacuum-dried to obtain intermediate product A.

[0106] B2. 217 parts by mass of o-cresol and 4.33 parts by mass of p-toluenesulfonic acid were mixed and then heated to 80°C with stirring to mix evenly. The temperature was then raised to 130°C and 46.2 parts by mass of intermediate product A were added over 65 minutes. The mixture was then kept warm for 5.5 hours and then cooled to 90°C. An aqueous sodium hydroxide solution was added dropwise to neutralize the p-toluenesulfonic acid in the reaction system. Unreacted o-cresol was then removed by distillation under reduced pressure. The mixture was then dissolved in boiling toluene and washed three times with 80°C distilled water. The toluene layer obtained after washing was cooled to -18°C, then filtered, recrystallized, and vacuum dried to obtain intermediate product B.

[0107] B3. Mix 200 parts by mass of dichloromethane and 42.8 parts by mass of cyanogen chloride, then cool to -5°C, and add a mixture obtained by mixing 105 parts by mass of intermediate product B, 92 parts by mass of triethylamine, and 200 parts by mass of butanone under nitrogen protection within 45 minutes. The reaction temperature is controlled at 0°C and the reaction is kept warm for 2 hours. After the reaction is completed, the generated triethylamine salt is removed by washing with water, followed by acid washing, alkali washing, water washing, and layering to obtain an organic phase, which is then dried over anhydrous sodium sulfate and then distilled under reduced pressure to remove dichloromethane to obtain a cyanate ester monomer.

[0108] (Comparative Example 1)

[0109] The only difference between Comparative Example 1 and Example 2 is that the epoxy insulating adhesive for ultra-low temperature environment uses hollow porous zirconium tungstate instead of hollow porous zirconium tungstate modified with a silane coupling agent. The remaining steps and components are the same as those in Example 2.

[0110] (Comparative Example 2)

[0111] The only difference between Comparative Example 2 and Example 2 is that the modified inorganic filler uses zirconium tungstate with a particle size of 10 μm modified by a silane coupling agent instead of hollow porous zirconium tungstate modified by a silane coupling agent; the remaining steps and components are the same as Example 2.

[0112] (Comparative Example 3)

[0113] The difference between Comparative Example 3 and Example 2 is that the organosilicon toughening agent is obtained by reacting a silane ring body with 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane; the specific steps are as follows: 20 parts by mass of 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, 500 parts by mass of tetramethyltetravinylcyclotetrasiloxane, and 1 part by mass of trifluoromethanesulfonic acid are mixed, followed by reaction at 82° C. for 6 hours, followed by addition of 2 parts by mass of calcium carbonate to neutralize the trifluoromethanesulfonic acid, followed by filtration and reduced pressure distillation to remove unreacted siloxane ring bodies and small molecular siloxanes, and then naturally cooled to room temperature to obtain an organosilicon toughening agent;

[0114] The silane ring is obtained by mixing trimethyltris(trifluoropropyl)cyclotrisiloxane and tetramethyltetravinylcyclotetrasiloxane in a molar ratio of 1:1; the remaining steps and components are the same as those in Example 2.

[0115] (Comparative Example 4)

[0116] The difference between Comparative Example 4 and Example 2 is that the cyanate monomer uses commercially available 1,1-bis(4-cyanophenyl)ethane; the remaining steps and components are the same as those in Example 2.

[0117] (Comparative Example 5)

[0118] The difference between Comparative Example 5 and Example 2 lies in step (2), which is as follows: under nitrogen protection, the epoxy resin and silicone toughening agent weighed in step (1) are mixed and stirred at high speed for 30 minutes, stirred at 50°C for 20 minutes, and then the modified inorganic filler is added and stirred for 60 minutes, followed by ultrasonic dispersion for 60 minutes, and then the active diluent, thixotropic agent, and wetting and leveling agent are added and mixed thoroughly, and packaged for use to obtain component A; the remaining steps and components are the same as those in Example 2.

[0119] Effect Examples

[0120] The ultra-low temperature epoxy insulating adhesives obtained in the examples and comparative examples were placed in a UV aging chamber with a wavelength of 313 nm, taken out after 7 days, and tested for yellowness index using a spectrophotometer. A larger yellowness index indicates more severe yellowing.

[0121] Table 1 below shows the performance test results of the epoxy insulation adhesives for ultra-low temperature environments prepared in Examples and Comparative Examples:

[0122] Table 1

[0123]

[0124]

[0125] The data in Table 1 show that the epoxy insulation adhesive for ultra-low temperature environments prepared by the present invention has good mechanical properties, low temperature resistance, and yellowing resistance.

[0126] Compared with Example 2, the only difference between Comparative Example 1 and Example 2 is that the epoxy insulation adhesive for ultra-low temperature environment uses hollow porous zirconium tungstate instead of hollow porous zirconium tungstate modified with a silane coupling agent. The porous zirconium tungstate has poor dispersion in the epoxy insulation adhesive and agglomeration occurs. The mechanical properties and low-temperature resistance of the obtained epoxy insulation adhesive are poor.

[0127] Compared with Example 2, Comparative Example 2 differs only in that the modified inorganic filler uses zirconium tungstate with a particle size of 10 μm modified by a silane coupling agent rather than hollow porous zirconium tungstate modified by a silane coupling agent. The mechanical properties and low-temperature resistance of the epoxy insulating adhesive prepared are poor.

[0128] Compared with Example 2, Comparative Example 3 differs in that the organosilicon toughening agent is obtained by reacting a silane ring body with 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane; the mechanical properties, low-temperature resistance, and yellowing resistance of the prepared epoxy insulating adhesive for ultra-low temperature environments are poor.

[0129] Comparative Example 4 is compared with Example 2, except that the cyanate monomer uses commercially available 1,1-bis(4-cyanophenyl)ethane; the mechanical properties and low-temperature resistance of the prepared epoxy insulating adhesive for ultra-low temperature environments are poor.

[0130] Comparative Example 5 is compared with Example 2, except that no photoinitiator is added in step (2) to carry out the photoinitiated reaction, and the mechanical properties and low-temperature resistance of the epoxy insulating adhesive obtained are poor.

[0131] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An epoxy insulating adhesive for ultra-low temperature environment, comprising component A and component B, characterized in that: The raw materials of component A include, by weight, 56 to 58 parts of epoxy resin, 17 to 19 parts of modified inorganic filler, 13 to 15 parts of silicone toughening agent, 3 to 4 parts of reactive diluent, 0.4 to 0.6 parts of thixotropic agent, and 0.3 to 0.5 parts of wetting and leveling agent; the raw materials of component B include, by weight, 6 to 10 parts of cyanate monomer, 2 to 4 parts of 4-methyltetrahydrophthalic anhydride, and 0.3 to 0.5 parts of accelerator.

2. The epoxy insulation adhesive for ultra-low temperature environment according to claim 1, characterized in that: The modified inorganic filler is a hollow porous zirconium tungstate modified by a silane coupling agent.

3. The epoxy insulating adhesive for ultra-low temperature environment according to claim 1, characterized in that: The organic silicon toughening agent is obtained by firstly reacting unsaturated bond-containing triazine with tetramethyldisiloxane and then reacting with 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane and a silane ring body.

4. The epoxy insulation adhesive for ultra-low temperature environment according to claim 3, characterized in that: The triazine containing an unsaturated bond is synthesized by oxidative ring-closure of 5-ethynyl-2-hydroxybenzaldehyde and 4-[(amidinothio)methyl]styrene hydrochloride under the catalysis of copper acetate monohydrate.

5. The epoxy insulation adhesive for ultra-low temperature environment according to claim 1, characterized in that: The cyanate monomer is obtained by reacting 5,6,11,12-tetrahydrodibenzo[a,e][8]annulene-2,9-dicarboxylic acid with 4-methoxymethylaniline, followed by reacting with o-cresol, and finally performing a cyanate esterification reaction.

6. A method for preparing the epoxy insulating adhesive for ultra-low temperature environment according to any one of claims 1 to 5, characterized in that: The method comprises the following preparation steps: (1) Weigh each raw material component according to its own mass fraction; (2) Under nitrogen protection, the epoxy resin and silicone toughening agent weighed in step (1) are mixed and stirred at high speed shear for 25 to 35 minutes, stirred at 48 to 52° C. for 18 to 22 minutes, and then the modified inorganic filler and the photoinitiator with a mass of 0.004 to 0.006 times of the modified inorganic filler are added and continued to stir for 55 to 65 minutes, followed by ultrasonic dispersion for 55 to 65 minutes, and continued to be irradiated with a UV-LED point light source with a wavelength of 365 nm for 1 to 2 hours under stirring conditions, and then the reactive diluent, thixotropic agent, and wetting and leveling agent are added and fully mixed, and packaged for use to obtain component A; (3) The cyanate monomer, 4-methyltetrahydrophthalic anhydride and accelerator weighed in step (1) are fully mixed and packaged for later use to obtain component B. (4) Separately packing one portion of component A obtained in step (2) and one portion of component B obtained in step (3) to form a group of epoxy insulating adhesive for ultra-low temperature environments.

7. The method for preparing epoxy insulating adhesive for ultra-low temperature environment according to claim 6, characterized in that: The modified inorganic filler is prepared as follows: adding the hollow porous zirconium tungstate to a 90wt% ethanol aqueous solution with a mass of 100 times that of the hollow porous zirconium tungstate, and ultrasonically dispersing the mixture to obtain a dispersion A; adding a silane coupling agent with a mass of 0.06 to 0.08 times that of the hollow porous zirconium tungstate to ethanol with a mass of 100 times that of the hollow porous zirconium tungstate, mixing the mixture, standing for 115 to 125 minutes, adding the mixture to the dispersion A, stirring for 25 to 35 minutes, ultrasonically dispersing the mixture for 4 to 6 minutes, and then centrifugally washing the mixture three times with ethanol in a centrifuge, and then drying the mixture to obtain the modified inorganic filler.

8. The method for preparing epoxy insulating adhesive for ultra-low temperature environment according to claim 6, characterized in that: The preparation steps of the organosilicon toughening agent are as follows: A1. 100 parts by mass of an unsaturated triazine was mixed with 4.5 to 5 parts by mass of a Custer catalyst, and then the temperature was raised to 75 to 85°C. 350 to 400 parts by mass of tetramethyldisiloxane was then added dropwise at a rate of 1 to 3 seconds. After the addition was complete, the reaction was continued for 5.5 to 6.5 hours, followed by vacuum distillation to obtain triazinyltetramethyldisiloxane. A2. 14-16 parts by mass of triazinyltetramethyldisiloxane, 500 parts by mass of tetramethyltetravinylcyclotetrasiloxane, and 0.9-1.1 parts by mass of trifluoromethanesulfonic acid were mixed, followed by reaction at 80±5°C for 5.5-6.5 hours. Subsequently, 4-6 parts by mass of 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane were added and the reaction was continued for 5.5-6.5 hours. 1.8-2.2 parts by mass of calcium carbonate were then added to neutralize the trifluoromethanesulfonic acid. The mixture was then filtered and distilled under reduced pressure to remove unreacted siloxane rings and small molecular weight siloxanes. The mixture was naturally cooled to room temperature to obtain an organosilicon toughening agent.

9. The method for preparing epoxy insulating adhesive for ultra-low temperature environment according to claim 8, characterized in that: The preparation method of the triazine containing an unsaturated bond is as follows: 5-ethynyl-2-hydroxybenzaldehyde, 4-[(amidinothio)methyl]styrene hydrochloride, sodium carbonate, copper acetate monohydrate, and toluene are mixed and refluxed for 23.5 to 24.5 hours, then cooled to room temperature, added with water for azeotropic distillation of toluene, boiled with water three times, and then purified by silica gel column chromatography using petroleum ether and ethyl acetate in a volume ratio of 100:1 to obtain the triazine containing an unsaturated bond. The molar ratio of 5-ethynyl-2-hydroxybenzaldehyde, 4-[(amidinothio)methyl]styrene hydrochloride, sodium carbonate, and copper acetate monohydrate is (6.75 to 6.85):(11.35 to 11.45):(11.35 to 11.45):(2.9 to 3.0); and the mass of toluene is 17 to 18 times the mass of 5-ethynyl-2-hydroxybenzaldehyde.

10. The method for preparing epoxy insulating adhesive for ultra-low temperature environment according to claim 6, characterized in that: The preparation method of the cyanate ester monomer is as follows: B1. 148-149 parts by mass of 5,6,11,12-tetrahydrodibenzo[a,e][8]annulene-2,9-dicarboxylic acid, 137-138 parts by mass of 4-methoxymethylaniline, 1.17-1.19 parts by mass of triphenyl phosphite, 3.07-3.09 parts by mass of N-methylpyrrolidone, 0.58-0.6 parts by mass of pyridine, and 298-302 parts by mass of calcium chloride were stirred and mixed, followed by reaction at 115-125°C under vacuum conditions for 9.5-10.5 hours. After cooling to room temperature, the mixture was poured into 200 parts by mass of methanol to form a precipitate. The mixture was then washed three times with methanol and distilled water at 70-90°C, filtered, and dried under vacuum to obtain an intermediate product A. B2. 215-217 parts by mass of o-cresol and 4.31-4.33 parts by mass of p-toluenesulfonic acid were mixed, then heated to 80 ° C and stirred to mix uniformly, then heated to 130 ° C, 46-46.2 parts by mass of intermediate product A were added within 55-65 min, and then kept warm for 4.5-5.5 h, then cooled to 80-90 ° C, and sodium hydroxide aqueous solution was added dropwise to neutralize the p-toluenesulfonic acid in the reaction system, followed by vacuum distillation to remove unreacted o-cresol, then dissolved in boiling toluene and washed three times with 70-80 ° C distilled water, the toluene layer obtained after washing was cooled to -18 ° C, then filtered, recrystallized, and vacuum dried to obtain intermediate product B; B3. 200 parts by mass of dichloromethane and 42.6 to 42.8 parts by mass of cyanogen chloride were mixed, and then cooled to -5°C. Under nitrogen protection, a mixture of 95 to 105 parts by mass of the intermediate product B, 90 to 92 parts by mass of triethylamine, and 200 parts by mass of butanone was added within 35 to 45 minutes. The reaction temperature was controlled at -5 to 0°C, and the reaction was kept warm for 2 hours. After the reaction was completed, the generated triethylamine salt was removed by washing with water, followed by acid washing, alkali washing, water washing, and layering to obtain an organic phase, which was then dried over anhydrous sodium sulfate and then distilled under reduced pressure to remove dichloromethane to obtain a cyanate monomer.

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