Modified epoxy resin potting adhesive and preparation method thereof

Abstract

The application relates to the field of pouring sealant, and discloses a modified epoxy resin pouring sealant and a preparation method thereof. The pouring sealant comprises an epoxy resin, modified inorganic fillers, modified additives and an auxiliary agent. The modified inorganic fillers are prepared by grafting quaternary ammonium s-triazine derivatives onto inorganic fillers. The quaternary ammonium s-triazine derivatives are prepared by sequentially substituting 3,5-diaminophenyl boronic acid, cyanuric chloride and 3-chloropropyl trimethoxysilane with 1,4-butanediamine, and then reacting with N,N-dimethyl-1,3-diaminopropane and quaternized by bromoethane. The modified additives are prepared by using modified bismaleimide monomers prepared from maleic anhydride and 5(6)-amino-1-(4-aminophenyl)-1,3,3-trimethylindane and 1-methyl-4-isopropyl cyclohexene by self-stabilizing precipitation polymerization. The pouring sealant prepared by the application has high tensile strength, good impact resistance, good heat resistance, good flame retardance, good dielectricity and good bacteriostasis.

Description

Technical Field

[0001] This invention belongs to the field of potting compound technology, specifically relating to a modified epoxy resin potting compound and its preparation method. Background Technology

[0002] Encapsulation is a liquid active compound composed of a resin matrix, curing agent (or crosslinking agent), filler, etc. Before curing, it is fluid and can be poured into and penetrate into the gaps inside electronic devices. Under certain conditions, it cures into a thermosetting composite material, which plays a role in bonding, fixing, waterproofing, moisture-proofing, dustproofing and insulation. Among them, epoxy resin encapsulation has high bonding strength, good sealing stability, chemical resistance, weather resistance and aging resistance, waterproofing and moisture-proofing, and excellent comprehensive mechanical and electrical properties, making it one of the most widely used encapsulations for electronic devices.

[0003] However, epoxy resin is a flammable material and produces a large amount of toxic gas when burned, which severely restricts its application in the field of electronic potting. The existing technology of adding flame retardants is the most direct and simple method to improve the flame retardant performance of epoxy resin potting compounds. According to the type of flame retardant, they can be divided into halogenated flame retardants and halogen-free flame retardants. Halogenated flame retardants release a large amount of toxic fumes when burning, causing "secondary disasters". Traditional halogen-free flame retardant systems have problems such as low flame retardant efficiency, large addition amount and poor compatibility with matrix materials, which leads to a significant reduction in the mechanical properties of the material. In addition, existing epoxy resin potting compounds are relatively brittle and do not perform well in terms of impact resistance, heat resistance and antibacterial properties, thus limiting their application range. Summary of the Invention

[0004] To address the shortcomings mentioned in the background art, the present invention aims to provide a modified epoxy resin potting compound and its preparation method. By adding modified inorganic fillers and modified additives, the prepared potting compound has high tensile strength, good impact resistance, and also possesses good heat resistance, flame retardancy, dielectric properties, and antibacterial properties.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A modified epoxy resin potting compound comprises the following components in parts by weight: 70-95 parts epoxy resin, 10-20 parts modified inorganic filler, 2-6 parts modified additive, 20-40 parts curing agent, 1-3 parts curing accelerator, and 15-30 parts diluent.

[0007] The modified inorganic filler is prepared by grafting a quaternized triazine derivative onto the surface of an inorganic filler using a chemical reaction. The quaternized triazine derivative is prepared by reacting a triazine monosubstituted product with cyanuric chloride via a substitution reaction, followed by a substitution reaction with 3-chloropropyltrimethoxysilane to obtain a triazine intermediate. Then, 1,4-butanediamine is used as a "bridging agent" to react with the triazine intermediate to obtain a triazine derivative. Subsequently, N,N-dimethyl-1,3-diaminopropane is used to react with the triazine derivative, and quaternization is performed using bromoethane.

[0008] The modified additive is prepared by using maleic anhydride and 5(6)-amino-1-(4-aminophenyl)-1,3,3-trimethylindane as raw materials, and then using the p-toluenesulfonic acid cyclization method to obtain the modified bismaleimide monomer. Then, using 1-methyl-4-isopropylcyclohexene and the modified bismaleimide monomer as monomer raw materials, it is polymerized by self-stabilizing precipitation polymerization.

[0009] Preferably, the preparation method of the modified inorganic filler includes the following steps: taking the inorganic filler and ultrasonically dispersing it in anhydrous ethanol and deionized water, then adding the quaternized triazine derivative, stirring and reacting at 60~80℃ for 8~12h, and after the reaction is completed, filtering, washing and drying to prepare the modified inorganic filler;

[0010] The inorganic filler is one or more of the following: silica powder, nano silica, aluminum hydroxide, graphene oxide, talc, nano titanium dioxide, alumina, montmorillonite, and boron nitride.

[0011] Preferably, the preparation method of the quaternized triazine derivative includes the following steps:

[0012] I. Take cyanuric chloride and toluene solvent in a reactor, maintain the reaction temperature at -5~0℃, and then slowly add a mixed solution of 3,5-diaminophenylboronic acid and toluene and stir for 4~6h. Triethylamine is added in batches during the reaction. After the reaction is completed, wash until neutral, dry the organic layer with anhydrous sodium sulfate and concentrate to prepare the mesotriazine monosubstituted product.

[0013] II. Under nitrogen protection, the mesentrin monosubstituted product and N,N-dimethylformamide were placed in a reactor, and 3-chloropropyltrimethoxysilane and triethylamine were added. The mixture was stirred at 55-65°C for 5-7 hours. After the reaction solution cooled to room temperature, it was slowly poured into ice water with vigorous stirring. After extraction, the organic phase was washed, dried, rotary evaporated, and purified by column chromatography to prepare the mesentrin intermediate.

[0014] III. Take 1,4-butanediamine and acetone solvent in a reactor, stir evenly, and slowly add a mixed solution of triazine intermediate and acetone. Maintain the reaction temperature of the system at 30-35℃, and adjust the pH of the reaction system to 6-7 using sodium hydroxide aqueous solution. Continue the reaction for 3-4 hours. After the reaction is completed, filter, wash and dry to prepare the triazine derivative.

[0015] IV. Add small amounts of the triazine derivative to N,N-dimethyl-1,3-diaminopropane in multiple batches, control the reaction temperature at 100~105℃, stir the reaction for 4~6h, and after the reaction solution is cooled to room temperature, dissolve it in toluene and wash it with saturated sodium chloride aqueous solution. Dry the organic layer with anhydrous sodium sulfate, filter and rotary evaporate to prepare the modified triazine derivative.

[0016] V. Add bromoethane to a mixed solution of the modified triazine derivative and acetone, heat to 55-60℃, stir for 4-6 hours, concentrate under reduced pressure and recrystallize with ethyl acetate to prepare the quaternized triazine derivative.

[0017] Preferably, the molar ratio of cyanuric chloride and 3,5-diaminophenylboronic acid in step I is 1:1 to 1.1.

[0018] Preferably, in step II, the molar ratio of the triazine monosubstituted product and 3-chloropropyltrimethoxysilane is 1:1 to 1.2.

[0019] Preferably, the molar ratio of 1,4-butanediamine and triazine intermediate in step III is 1:2 to 2.2.

[0020] Preferably, the method for preparing the modified additive includes the following steps:

[0021] ① Take maleic anhydride, N,N-dimethylacetamide and toluene in a reactor. After the maleic anhydride is completely dissolved, add dropwise a mixed solution of 5(6)-amino-1-(4-aminophenyl)-1,3,3-trimethylindane and N,N-dimethylacetamide. Keep at room temperature for 2.5~3.5h. Then add p-toluenesulfonic acid, heat to 110~115℃ and keep at temperature for 4.5~5.5h. Then add boiling water containing sodium bicarbonate, extract and wash until neutral. Remove solvent by rotary evaporation and dry to prepare modified bismaleimide monomer.

[0022] ② Take the modified bismaleimide monomer and cyclohexanone in a reactor, stir to dissolve, then add n-nonane, 1-methyl-4-isopropylcyclohexene and initiator dicumyl peroxide, purge with nitrogen for 30 min to remove oxygen, and react at 125~130℃ for 5.5~6 h. After the reaction is complete, wash away the unreacted material, replace the solvent with methyl tert-butyl ether, and then vacuum dry to prepare the modified additive.

[0023] Preferably, in step ②, the addition ratio of modified bismaleimide monomer, cyclohexanone, n-nonane, 1-methyl-4-isopropylcyclohexene and diisopropylbenzene peroxide is 0.65~0.7g: 7~7.5mL: 7~7.5mL: 0.41~0.44g: 0.025~0.03g.

[0024] Preferably, the epoxy resin is one of bisphenol A type epoxy resin, furan epoxy resin, and tetraglycidylamine type epoxy resin; the curing agent is one or a combination of methylhexahydrophthalic anhydride, diaminodiphenyl sulfone, phthalic anhydride, and 3-methyltetrahydrophthalic anhydride; the accelerator is one or a combination of 1,8-diazabicyclo[5.4.0]undec-7-ene, 2-ethyl-4-methylimidazolium, tertiary amine, and dicyandiamide; and the diluent is one or a combination of ethylene glycol diglycidyl ether, dodecyl glycidyl ether, and neopentyl glycol diglycidyl ether.

[0025] The preparation method of the modified epoxy resin potting compound as described above includes the following steps:

[0026] S1. Weigh each component according to the weight parts, mix the epoxy resin and the modified additive, and preheat at 125~130℃ for 40~60min to prepare the premix.

[0027] S2. Cool the system to 75~85℃, add modified inorganic filler, curing agent, curing accelerator and diluent to the premix and stir evenly to prepare the mixture;

[0028] S3. Transfer the mixture to a grinder for grinding and dispersion, then degas under vacuum for 20-60 minutes, and then pour it into a mold for high-temperature curing to prepare the modified epoxy resin potting compound.

[0029] The beneficial effects of this invention are:

[0030] This invention utilizes a substitution reaction between 3,5-diaminophenylboronic acid and a chlorine atom in cyanuric chloride to prepare a monosubstituted triazine derivative. Then, 3-chloropropyltrimethoxysilane is used to further substitute the ungrafted amino group in the monosubstituted triazine derivative to prepare a triazine intermediate. Subsequently, 1,4-butanediamine is used as a bridging agent to allow the amino groups at both ends of the 1,4-butanediamine to substitute the second chlorine atom in the triazine intermediate, respectively, to prepare a triazine derivative. Next, N,N-dimethyl-1,3-diaminopropane is used to substitute the remaining chlorine atom in the triazine derivative to prepare a modified triazine derivative. Finally, bromoethane is used to quaternize the modified triazine derivative to prepare a quaternized triazine derivative.

[0031] The quaternized triazine derivative prepared in this invention incorporates a triazine ring structure with good thermal stability and N-Si-B elements with synergistic flame-retardant effects, endowing the adhesive with excellent heat resistance and flame retardancy. Simultaneously, the introduction of quaternary ammonium salt ions with antibacterial activity provides a precursor for binding with bacteria. Since bacteria have polysaccharide molecules on their surface, the introduction of boric acid can enhance the adhesive's ability to capture bacteria through chemical bonding. Both synergistically exert a good antibacterial effect. Furthermore, this invention utilizes the silanol groups generated by the hydrolysis of the methoxysilyl groups introduced in the quaternized triazine derivative to undergo dehydration condensation with the hydroxyl groups on the surface of the inorganic filler, preparing a modified inorganic filler. This improves the dispersion uniformity of the inorganic filler in the adhesive and avoids the decrease in mechanical properties caused by particle agglomeration.

[0032] This invention utilizes maleic anhydride and 5(6)-amino-1-(4-aminophenyl)-1,3,3-trimethylindane as raw materials, and synthesizes modified bismaleimide monomers containing indane structures using the p-toluenesulfonic acid cyclization method. Then, using 1-methyl-4-isopropylcyclohexene and the modified bismaleimide monomers as monomer raw materials, a self-stabilizing precipitation polymerization method is used to prepare a cross-linked polymer microsphere modified additive. This modified additive contains multiple benzene ring structures, which improves molecular stiffness and endows the rubber with excellent heat resistance. At the same time, the introduced asymmetric indane ring reduces the regularity of the molecular structure, which helps to lower the melting point. Furthermore, the cross-linked polymer microsphere structure of the modified additive can endow the rubber with good impact resistance and low dielectric properties. Detailed Implementation

[0033] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0034] Example 1: A method for preparing a quaternized triazine derivative includes the following steps:

[0035] I. Take 9.2g of cyanuric chloride and 100mL of toluene solvent in a reactor, maintain the reaction temperature at 0℃, and then slowly add a mixed solution of 7.6g of 3,5-diaminophenylboronic acid and 10mL of toluene and stir for 5h. During the reaction, add 5.1g of triethylamine in batches. After the reaction is completed, wash until neutral, dry the organic layer with anhydrous sodium sulfate and concentrate to prepare the mestriazine monosubstituted product;

[0036] II. Under nitrogen protection, 11.9 g of the monosubstituted triazine and 120 mL of N,N-dimethylformamide were placed in a reactor, along with 8.1 g of 3-chloropropyltrimethoxysilane and 4 g of triethylamine. The mixture was stirred at 60 °C for 6 h. After the reaction solution cooled to room temperature, it was slowly poured into ice water under vigorous stirring. After extraction, the organic phase was washed, dried, rotary evaporated, and purified by column chromatography to prepare the triazine intermediate.

[0037] III. Take 0.9 g of 1,4-butanediamine and 20 mL of acetone solvent in a reactor, stir evenly, and slowly add 10.2 g of triazine intermediate and 50 mL of acetone mixed solution. Maintain the reaction temperature of the system at 35 °C, and adjust the pH value of the reaction system to 7 using a 1 mol / L sodium hydroxide aqueous solution. Continue the reaction for 4 h. After the reaction is completed, filter, wash and dry to prepare the triazine derivative.

[0038] IV. Take 9.3g of the triazine derivative and add it to 12.2g of N,N-dimethyl-1,3-diaminopropane in small amounts several times. Control the reaction temperature at 102℃ and stir for 5h. After the reaction solution cools to room temperature, dissolve it in 50mL of toluene and wash it with saturated sodium chloride aqueous solution. Dry the organic layer with anhydrous sodium sulfate, filter and evaporate by rotary evaporation to prepare the modified triazine derivative.

[0039] V. Take 2.7g of bromoethane and add it to a mixed solution of 10.7g of modified triazine derivative and 40mL of acetone. Heat to 60℃ and stir for 5h. After the reaction is completed, concentrate under reduced pressure and recrystallize with ethyl acetate to prepare the quaternized triazine derivative.

[0040] Example 2 A method for preparing modified silicon micro powder includes the following steps: 5g of silicon micro powder is ultrasonically dispersed in 90mL of anhydrous ethanol and 20mL of deionized water, and then 4.4g of the quaternized triazine derivative prepared in Example 1 is added. The mixture is stirred at 65°C for 10h. After the reaction is completed, the mixture is filtered, washed and dried to obtain modified silicon micro powder.

[0041] Example 3: A method for preparing a modified additive includes the following steps:

[0042] ① Take 2.1 g of maleic anhydride, 20 mL of N,N-dimethylacetamide and 10 mL of toluene in a reactor. After the maleic anhydride is completely dissolved, add 2.8 g of a mixed solution of 5(6)-amino-1-(4-aminophenyl)-1,3,3-trimethylindane and 20 mL of N,N-dimethylacetamide. Keep at room temperature for 3 h. Then add 0.05 g of p-toluenesulfonic acid, heat to 112 °C and keep at temperature for 5 h. Then add to 50 mL of 5% sodium bicarbonate boiling water. Extract with ethyl acetate and wash until neutral. Remove the solvent by rotary evaporation and dry to prepare the modified bismaleimide monomer.

[0043] ② Take 0.69 g of modified bismaleimide monomer and 7.5 mL of cyclohexanone in a reactor, stir to dissolve, then add 7.5 mL of n-nonane, 0.44 g of 1-methyl-4-isopropylcyclohexene and 0.027 g of initiator dicumyl peroxide. After purging with nitrogen for 30 min to remove oxygen, react at 130 °C for 6 h. After the reaction is complete, wash away the unreacted material, replace the solvent with methyl tert-butyl ether, and then dry under vacuum to prepare the modified additive.

[0044] Example 4 A modified epoxy resin potting compound comprising the following components by weight: 73 parts epoxy resin E51, 10.8 parts modified silica powder prepared in Example 2, 2.1 parts modified additive prepared in Example 3, 22 parts curing agent methylhexahydrophthalic anhydride, 1.1 parts curing accelerator 1,8-diazabicyclo[5.4.0]undec-7-ene, and 17 parts diluent ethylene glycol diglycidyl ether.

[0045] The preparation method of the above-mentioned modified epoxy resin potting compound includes the following steps:

[0046] S1. Weigh each component according to the weight parts, mix the epoxy resin and the modified additive, and preheat at 130℃ for 50 min to prepare the premix.

[0047] S2. Cool the system to 80°C, add modified silica powder, curing agent, curing accelerator and diluent to the premix and stir evenly to prepare the mixture;

[0048] S3. Transfer the mixture to a grinder for grinding and dispersion, then degas under vacuum for 30 minutes, and then pour it into a mold for high-temperature curing to prepare the modified epoxy resin potting compound.

[0049] Example 5 A modified epoxy resin potting compound comprising the following components by weight: 81 parts epoxy resin E51, 15.5 parts modified silica powder prepared in Example 2, 3.3 parts modified additive prepared in Example 3, 31 parts curing agent methylhexahydrophthalic anhydride, 1.7 parts curing accelerator 1,8-diazabicyclo[5.4.0]undec-7-ene, and 23 parts diluent ethylene glycol diglycidyl ether.

[0050] The preparation method of the modified epoxy resin potting compound is the same as in Example 4.

[0051] Example 6 A modified epoxy resin potting compound comprising the following components by weight: 93 parts epoxy resin E51, 19.1 parts modified silica powder prepared in Example 2, 5.5 parts modified additive prepared in Example 3, 38 parts curing agent methylhexahydrophthalic anhydride, 2.4 parts curing accelerator 1,8-diazabicyclo[5.4.0]undec-7-ene, and 27 parts diluent ethylene glycol diglycidyl ether.

[0052] The preparation method of the modified epoxy resin potting compound is the same as in Example 4.

[0053] Comparative Example 1: A method for preparing modified silica powder includes the following steps: 5g of silica powder is ultrasonically dispersed in 90mL of anhydrous ethanol and 20mL of deionized water, and then 4.4g of the triazine derivative prepared in Example 1 is added. The mixture is stirred at 65°C for 10h. After the reaction is completed, the mixture is filtered, washed, and dried to obtain modified silica powder.

[0054] Comparative Example 2: A modified epoxy resin potting compound comprising the following components by weight: 93 parts epoxy resin E51, 19.1 parts modified silica powder prepared in Comparative Example 1, 5.5 parts modified additive prepared in Example 3, 38 parts curing agent methylhexahydrophthalic anhydride, 2.4 parts curing accelerator 1,8-diazabicyclo[5.4.0]undec-7-ene, and 27 parts diluent ethylene glycol diglycidyl ether.

[0055] The preparation method of the modified epoxy resin potting compound is the same as in Example 4.

[0056] Comparative Example 3: A modified epoxy resin potting compound comprising the following components by weight: 93 parts epoxy resin E51, 19.1 parts silica powder, 5.5 parts modified additive prepared in Example 3, 38 parts curing agent methylhexahydrophthalic anhydride, 2.4 parts curing accelerator 1,8-diazabicyclo[5.4.0]undec-7-ene, and 27 parts diluent ethylene glycol diglycidyl ether.

[0057] The preparation method of the modified epoxy resin potting compound is the same as in Example 4.

[0058] Comparative Example 4: A modified epoxy resin potting compound comprising the following components by weight: 93 parts epoxy resin E51, 19.1 parts modified silica powder prepared in Example 2, 5.5 parts modified bismaleimide monomer prepared in Example 3, 38 parts curing agent methylhexahydrophthalic anhydride, 2.4 parts curing accelerator 1,8-diazabicyclo[5.4.0]undec-7-ene, and 27 parts diluent ethylene glycol diglycidyl ether.

[0059] The preparation method of the modified epoxy resin potting compound is the same as in Example 4.

[0060] Comparative Example 5: A modified epoxy resin potting compound comprising the following components by weight: 93 parts epoxy resin E51, 19.1 parts modified silica powder prepared in Example 2, 38 parts curing agent methylhexahydrophthalic anhydride, 2.4 parts curing accelerator 1,8-diazabicyclo[5.4.0]undec-7-ene, and 27 parts dilution ethylene glycol diglycidyl ether.

[0061] The preparation method of the modified epoxy resin potting compound is the same as in Example 4.

[0062] Performance testing

[0063] The modified epoxy resin potting compounds prepared in Examples 4-6 and Comparative Examples 2-5 were subjected to performance testing:

[0064] (1) Tensile property test: Prepare a 160mm×10mm×4mm potting compound strip according to GB / T 2567-2021, and test the tensile properties of the sample. Temperature: 25℃, tensile rate: 5mm / min.

[0065] (2) Impact resistance test: Prepare potting compound samples of 25mm×25mm×3mm according to GB / T 6328-2021 and test their impact strength.

[0066] (3) Heat resistance test: Weigh 5~10mg of sample into a ceramic crucible and use a thermogravimetric analyzer to measure the thermal decomposition (TGA) curve. Wherein, N2 flow rate: 50mL / min, heating range: 50~800℃, heating rate: 20℃ / min, the heat resistance of the sample is evaluated by the initial thermal decomposition temperature.

[0067] (4) Limiting oxygen index test: Prepare a potting compound sample of 80mm×10mm×4mm for limiting oxygen index test. Place the sample in the limiting oxygen index instrument, ignite the top of the sample, and record the minimum oxygen concentration required for the sample to burn completely from top to bottom.

[0068] (5) Dielectric performance test: Prepare a potting compound sample of 20mm×20mm×2mm for dielectric performance test. The test frequency is 100MHz and the test temperature is 25℃.

[0069] (6) Antibacterial performance test: The antibacterial rate test was conducted in accordance with QB / T 2591-2003, and the test strain was Staphylococcus aureus.

[0070] The potting compounds prepared in Examples 4-6 of this invention exhibit high tensile strength, good impact resistance, and also possess excellent heat resistance, flame retardancy, dielectric properties, and antibacterial properties. In Comparative Example 2, the modified silica powder was not quaternized with the triazine derivative, and in Comparative Example 3, the silica powder was not modified. The measured antibacterial rates in Comparative Examples 2-3 were lower than those in Examples 4-6, with Comparative Example 3 showing a more significant decrease compared to Comparative Example 2. This indicates that the quaternary ammonium salt ions and boric acid structural units synergistically exert a better antibacterial effect. Furthermore, the tensile strength, impact strength, and limiting oxygen index in Comparative Example 3 were lower than those in Examples 4-6. This is attributed to the agglomeration of the microparticles, leading to a decrease in mechanical properties, and the absence of a thermally stable triazine ring structure and synergistic antibacterial effect. The presence of N-Si-B elements leads to a decrease in heat resistance and flame retardancy. In Comparative Example 4, the modified additive was replaced with an equal amount of modified bismaleimide monomer, while no modified additive was added in Comparative Example 5. The impact strength of Comparative Examples 4-5 was significantly lower than that of Examples 4-6, while the dielectric constant and dielectric loss were increased compared to Examples 4-6. This indicates that the addition of modified additives is beneficial to improving the impact resistance and dielectric properties of the potting compound. Furthermore, the initial thermal decomposition temperature of Comparative Example 5 was significantly lower than that of Examples 4-6, indicating that the modified bismaleimide monomer greatly improves the heat resistance of the potting compound to a certain extent.

[0071] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0072] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A modified epoxy resin potting compound, characterized in that, It includes the following components by weight: 70-95 parts epoxy resin, 10-20 parts modified inorganic filler, 2-6 parts modified additive, 20-40 parts curing agent, 1-3 parts curing accelerator, and 15-30 parts diluent; The modified inorganic filler is prepared by grafting a quaternized triazine derivative onto the surface of the inorganic filler using a chemical reaction; the preparation method of the quaternized triazine derivative includes the following steps: I. Take cyanuric chloride and toluene solvent in a reactor, maintain the reaction temperature at -5~0℃, and then slowly add a mixed solution of 3,5-diaminophenylboronic acid and toluene and stir for 4~6h. Triethylamine is added in batches during the reaction. After the reaction is completed, wash until neutral, dry the organic layer with anhydrous sodium sulfate and concentrate to prepare the mesotriazine monosubstituted product. II. Under nitrogen protection, the mesentrin monosubstituted product and N,N-dimethylformamide were placed in a reactor, and 3-chloropropyltrimethoxysilane and triethylamine were added. The mixture was stirred at 55-65°C for 5-7 hours. After the reaction solution cooled to room temperature, it was slowly poured into ice water with vigorous stirring. After extraction, the organic phase was washed, dried, rotary evaporated, and purified by column chromatography to prepare the mesentrin intermediate. III. Take 1,4-butanediamine and acetone solvent in a reactor, stir evenly, and slowly add a mixed solution of triazine intermediate and acetone. Maintain the reaction temperature of the system at 30-35℃, and adjust the pH of the reaction system to 6-7 using sodium hydroxide aqueous solution. Continue the reaction for 3-4 hours. After the reaction is completed, filter, wash and dry to prepare the triazine derivative. IV. Add small amounts of the triazine derivative to N,N-dimethyl-1,3-diaminopropane in multiple batches, control the reaction temperature at 100~105℃, stir the reaction for 4~6h, and after the reaction solution is cooled to room temperature, dissolve it in toluene and wash it with saturated sodium chloride aqueous solution. Dry the organic layer with anhydrous sodium sulfate, filter and rotary evaporate to prepare the modified triazine derivative. V. Add bromoethane to a mixed solution of the modified triazine derivative and acetone, heat to 55-60°C, stir for 4-6 hours, concentrate under reduced pressure and recrystallize with ethyl acetate to prepare the quaternized triazine derivative. In step I, the molar ratio of cyanuric chloride and 3,5-diaminophenylboronic acid is 1:1 to 1.

1. The modified additive is prepared by using maleic anhydride and 5(6)-amino-1-(4-aminophenyl)-1,3,3-trimethylindane as raw materials, and then using the p-toluenesulfonic acid cyclization method to obtain the modified bismaleimide monomer. Then, using 1-methyl-4-isopropylcyclohexene and the modified bismaleimide monomer as monomer raw materials, it is polymerized by self-stabilizing precipitation polymerization.

2. The modified epoxy resin potting compound according to claim 1, characterized in that, The preparation method of the modified inorganic filler includes the following steps: the inorganic filler is ultrasonically dispersed in anhydrous ethanol and deionized water, then a quaternized triazine derivative is added, and the mixture is stirred at 60~80℃ for 8~12h. After the reaction is completed, the mixture is filtered, washed and dried to obtain the modified inorganic filler. The inorganic filler is one or more of the following: silica powder, nano silica, aluminum hydroxide, graphene oxide, talc, nano titanium dioxide, alumina, montmorillonite, and boron nitride.

3. The modified epoxy resin potting compound according to claim 1, characterized in that, In step II, the molar ratio of the triazine monosubstituted product and 3-chloropropyltrimethoxysilane is 1:1 to 1.

2.

4. The modified epoxy resin potting compound according to claim 1, characterized in that, In step III, the molar ratio of 1,4-butanediamine to triazine intermediate is 1:2~2.

2.

5. The modified epoxy resin potting compound according to claim 1, characterized in that, The preparation method of the modified additive includes the following steps: ① Take maleic anhydride, N,N-dimethylacetamide and toluene in a reactor. After the maleic anhydride is completely dissolved, add dropwise a mixed solution of 5(6)-amino-1-(4-aminophenyl)-1,3,3-trimethylindane and N,N-dimethylacetamide. Keep at room temperature for 2.5~3.5h. Then add p-toluenesulfonic acid, heat to 110~115℃ and keep at temperature for 4.5~5.5h. Then add boiling water containing sodium bicarbonate, extract and wash until neutral. Remove solvent by rotary evaporation and dry to prepare modified bismaleimide monomer. ② Take the modified bismaleimide monomer and cyclohexanone in a reactor, stir to dissolve, then add n-nonane, 1-methyl-4-isopropylcyclohexene and initiator dicumyl peroxide, purge with nitrogen for 30 min to remove oxygen, and react at 125~130℃ for 5.5~6 h. After the reaction is complete, wash away the unreacted material, replace the solvent with methyl tert-butyl ether, and then vacuum dry to prepare the modified additive.

6. The modified epoxy resin potting compound according to claim 5, characterized in that, In step ②, the addition ratio of modified bismaleimide monomer, cyclohexanone, n-nonane, 1-methyl-4-isopropylcyclohexene, and diisopropylbenzene peroxide is 0.65~0.7g: 7~7.5mL: 7~7.5mL: 0.41~0.44g: 0.025~0.03g.

7. The modified epoxy resin potting compound according to claim 1, characterized in that, The epoxy resin is one of bisphenol A type epoxy resin, furan epoxy resin, and tetraglycidylamine type epoxy resin; the curing agent is one or more of methylhexahydrophthalic anhydride, diaminodiphenyl sulfone, phthalic anhydride, and 3-methyltetrahydrophthalic anhydride; the accelerator is one or more of 1,8-diazabicyclo[5.4.0]undec-7-ene, 2-ethyl-4-methylimidazolium, tertiary amine, and dicyandiamide; the diluent is one or more of ethylene glycol diglycidyl ether, dodecyl glycidyl ether, and neopentyl glycol diglycidyl ether.

8. The method for preparing the modified epoxy resin potting compound according to any one of claims 1 to 7, characterized in that, Includes the following steps: S1. Weigh each component according to the weight parts, mix the epoxy resin and the modified additive, and preheat at 125~130℃ for 40~60min to prepare the premix. S2. Cool the system to 75~85℃, add modified inorganic filler, curing agent, curing accelerator and diluent to the premix and stir evenly to prepare the mixture; S3. Transfer the mixture to a grinder for grinding and dispersion, then degas under vacuum for 20-60 minutes, and then pour it into a mold for high-temperature curing to prepare the modified epoxy resin potting compound.