Electronic-grade epoxy resin composition and preparation method thereof

Abstract

The invention discloses an electronic-grade epoxy resin composition and a preparation method thereof, belongs to the technical field of epoxy resin processing, and is used for solving the technical problem that the dielectric property and the mechanical property of electronic epoxy resin need to be further improved in the prior art. The light-cured epoxy resin composition comprises the following raw materials in parts by weight: 30-36 parts of epoxy resin, 35-40 parts of modified filler, 15-20 parts of modified toughened polyester, 5-10 parts of a curing agent, 1-2 parts of a photoinitiator and 1-6 parts of an auxiliary additive, and is prepared by taking bisphenol A epoxy resin as a base material and taking the modified filler and the modified toughened polyester as reinforcing materials. The curing agent, the photoinitiator and the auxiliary additive are used as auxiliaries, and the epoxy resin composition is obtained through sealed storage, so that the dielectric property, the heat dissipation property and the mechanical property of the electronic epoxy resin are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of epoxy resin processing, and particularly relates to an electronic-grade epoxy resin composition and a preparation method thereof. Background Art

[0002] With the rise of the fifth-generation mobile communication technology, emerging technologies such as driverless, wearable devices, and cloud computing have set new standards for signal transmission in integrated circuits. In high-speed communication circuits, microelectronic products are constantly developing in the direction of high-density integration, high-frequency signals, and high power. However, as a key substrate in microelectronic packaging, traditional epoxy resins are difficult to meet the development needs of high-performance circuit boards due to their relatively high dielectric constant, poor heat dissipation performance, and easy aging characteristics. Therefore, the preparation of a high-performance electronic-grade epoxy resin composition has become a popular research topic at present.

[0003] The main reason for the poor dielectric properties of traditional electronic-grade epoxy resins is that the three-dimensional network structure formed after curing of epoxy resins has microscopic pores and is prone to moisture absorption in a humid and hot environment. After water, as a polar medium, enters the material, it not only reduces the volume resistivity but also forms a conductive channel through ionization, further increasing the dielectric loss. Moreover, the synergistic effect between the rigid benzene ring and the flexible ether bond in the molecular structure of epoxy resins is insufficient, and the crosslinking density is too low, resulting in poor toughness of the material. High temperature is likely to cause molecular chain breakage, leading to a reduction in the encapsulation effect on electronic products. In addition, a humid and hot environment is likely to cause interface delamination and encapsulation layer peeling. And the molecular chain of epoxy resin itself is mainly composed of carbon, hydrogen, and oxygen elements, without strong thermal conductivity, resulting in low heat transfer efficiency inside the resin and difficulty in dissipating the heat generated by electronic products during operation.

[0004] In view of the technical defects in this regard, a solution is proposed. Summary of the Invention

[0005] The purpose of the present invention is to provide an electronic-grade epoxy resin composition and a preparation method thereof, which are used to solve the technical problem that the dielectric properties and mechanical properties of existing electronic epoxy resins need to be further improved.

[0006] The purpose of the present invention can be achieved by the following technical solutions: An electronic-grade epoxy resin composition includes the following raw materials in parts by weight: 30 - 36 parts of epoxy resin, 35 - 40 parts of modified filler, 15 - 20 parts of modified toughened polyester, 5 - 10 parts of curing agent, 1 - 2 parts of photoinitiator, and 1 - 6 parts of auxiliary additive;

[0007] The modified filler is obtained by the following method:

[0008] A1. Place the tetramethylammonium hydroxide solution, deionized water, and propanol in a reaction kettle, stir for 10 - 15 min, add γ-aminopropyltriethoxysilane, heat up to 40 - 50 °C, keep the temperature for reaction for 4 - 6 h, and perform post-treatment to obtain the modified polysiloxane;

[0009] The reaction principle for the preparation of the modified polysiloxane is as follows:

[0010] During the reaction process, under the catalysis of tetramethylammonium hydroxide, the ethoxysilane functional groups in γ-aminopropyltriethoxysilane undergo hydrolysis reactions to generate silanols, and the silanols further undergo condensation reactions to obtain the modified polysiloxane.

[0011] A2. Place the deionized water, isopropanol, and fluorinated nano-boron nitride in a reaction kettle, add sodium hydroxide solution to adjust the pH = 9 ± 0.5, add the modified polysiloxane, heat up to 40 - 50 °C, keep the temperature for reaction for 3 - 4 h, and perform post-treatment to obtain the modified filler.

[0012] The reaction principle for the preparation of the modified filler is as follows:

[0013] During the reaction process, the amino functional groups of the modified polysiloxane undergo chemical bonding with the epoxy functional groups modified by silane coupling agent on the surface of the fluorinated nano-boron nitride to form chemical bonds, and a layer of fluorinated nano-boron nitride is formed on the surface of the modified polysiloxane skeleton to obtain the modified filler.

[0014] Furthermore, in step A1, the concentration of the tetramethylammonium hydroxide solution is 75 - 80 wt%, and the dosage ratio of the tetramethylammonium hydroxide solution, deionized water, propanol, and γ-aminopropyltriethoxysilane is 3 - 5 mL:500 - 620 mL:18 - 20 mL:100 - 110 g. The post-treatment steps include: after the reaction is completed, wait for the reaction system to cool to room temperature, add tetrahydrofuran to the reaction solution, precipitate solids, perform suction filtration, wash the filter cake with deionized water 1 - 2 times, transfer it to a drying oven at 70 - 80 °C, and dry to constant weight to obtain the modified polysiloxane; in step A2, the concentration of the sodium hydroxide solution is 0.5 - 1.0 mol / mL, and the dosage ratio of the deionized water, isopropanol, fluorinated nano-boron nitride, and modified polysiloxane is 15 - 20 mL:15 - 20 mL:1.5 - 2 g:7 - 10 g. The post-treatment steps include: after the reaction is completed, perform suction filtration, wash the filter cake with deionized water and ethanol 1 - 2 times, transfer it to a drying oven at 70 - 80 °C, and dry to constant weight to obtain the modified filler.

[0015] Furthermore, the fluorinated nano-boron nitride is obtained by the following preparation method:

[0016] B1. Place nano boron nitride, deionized water and ethanol in a reaction kettle, heat up to 40 - 50 °C, ultrasonically treat for 20 - 30 min, and dry to obtain pretreated nano boron nitride;

[0017] The reaction principle for the preparation of pretreated nano boron nitride is as follows:

[0018] During the reaction process, the high-frequency vibration generated by ultrasonic waves will exert an impact force on the surface of nano boron nitride. This mechanical vibration can decompose the organic or inorganic substances attached to the surface and remove the dirt and impurities on the particle surface.

[0019] B2. Place the pretreated nano boron nitride, ethanol and deionized water in a reaction kettle, heat up to 40 - 50 °C, add γ - glycidoxypropyltrimethoxysilane and perfluorooctyltrimethoxysilane, keep the temperature for reaction for 1 - 2 h, and perform post-treatment to obtain fluorinated nano boron nitride;

[0020] The reaction principle for fluorinated nano boron nitride is as follows:

[0021] During the reaction process, the three siloxane bonds of γ - glycidoxypropyltrimethoxysilane and perfluorooctyltrimethoxysilane are hydrolyzed by deionized water into silanols. The silanols further undergo a condensation reaction with the hydroxyl groups on the surface of nano boron nitride to obtain fluorinated nano boron nitride modified by a silane coupling agent.

[0022] Furthermore, in step B1, the dosage ratio of the nano boron carbide, deionized water and ethanol is 10 - 15 g:50 - 70 mL:50 - 70 mL. In step B2, the dosage ratio of the pretreated nano boron nitride, ethanol, deionized water, perfluorooctyltrimethoxysilane and γ - glycidoxypropyltrimethoxysilane is 8 - 12 g:100 - 120 mL:10 - 15 mL:5 - 8 g:3 - 4 g. The post-treatment steps include: after the reaction is completed, perform suction filtration, wash the filter cake with deionized water and ethanol for 1 - 2 times, transfer it to a drying oven at a temperature of 50 - 60 °C, and dry to constant weight to obtain fluorinated nano boron nitride.

[0023] Furthermore, the preparation method of the modified toughened polyester is as follows: Place polyethylene glycol, dibutyltin dilaurate and tetrahydrofuran in a reaction kettle protected by a nitrogen atmosphere, heat up to 45 - 55 °C, stir for 20 - 30 min, add isophorone diisocyanate, keep the temperature for reaction for 1 - 2 h, add a chain extender to the reaction kettle, keep the temperature for reaction for 0.5 - 1 h, add a capping agent, and keep the temperature for reaction for 1 - 2 h, and perform post-treatment to obtain the modified toughened polyester.

[0024] The reaction formula for the preparation of the modified toughened polyester is as follows:

[0025]

[0026] Where:

[0027] The preparation reaction principle of the modified toughened polyester is as follows:

[0028] During the reaction process, under the catalysis of dibutyltin dilaurate, the alcohol hydroxyl group of polyethylene glycol and the isocyanate group of isophorone diisocyanate undergo a nucleophilic reaction to obtain an intermediate capped with isophorone diisocyanate. The isocyanate group of the intermediate further undergoes a nucleophilic reaction with the alcohol hydroxyl group of the chain extender dipentaerythritol, and the obtained product reacts with the capping agents 2-hydroxyisopropyl methacrylate and γ-aminopropyltriethoxysilane to obtain the modified toughened polyester.

[0029] Furthermore, the dosage ratio of the polyethylene glycol, tetrahydrofuran, dibutyltin dilaurate, chain extender and capping agent is 10 - 15 g: 200 - 250 mL: 0.5 - 1 g: 3.5 - 5.5 g: 4 - 6 g. The chain extender is dipentaerythritol. The capping agent is composed of 2-hydroxyisopropyl methacrylate and γ-aminopropyltriethoxysilane according to a mass ratio of 2:1. The dosage of isophorone diisocyanate is 2.1 times the total molar amount of the hydroxyl groups of polyethylene glycol. The post-treatment step includes: after the reaction is completed, the temperature is raised to 70 - 80 °C, and vacuum distillation is carried out until no liquid is collected, obtaining the modified toughened polyester prepolymer.

[0030] The present invention also provides a preparation method of an electronic-grade epoxy resin composition, comprising the following steps:

[0031] S1. Place the epoxy resin and auxiliary additives in a vacuum stirring and defoaming machine, mix evenly, and carry out vacuum defoaming to obtain an epoxy resin mixture;

[0032] S2. Place the curing agent, modified filler and modified toughened polyester in a vacuum stirring and defoaming machine, mix evenly, and carry out vacuum defoaming to obtain a curing agent mixture;

[0033] S3. Mix the epoxy resin mixture, photoinitiator and curing agent mixture evenly, and store them sealed to obtain the epoxy resin composition.

[0034] Furthermore, in step S1, the epoxy resin is bisphenol A epoxy resin. The auxiliary additives are composed of a diluent, an antistatic agent, an antifoaming agent and a pigment according to a mass ratio of 5:2:1:2. The diluent is one or more of dibutyl phthalate, butanediol diglycidyl ether and glycidyl 12 - 14 alkyl ether. The antistatic agent is one or two of 1-ethyl-3-methylimidazolium tetrafluoroborate and 1-butyl-3-methylimidazolium hexafluorophosphate. The antifoaming agent is polydimethylsiloxane. The pigment is one or two of phthalocyanine blue and titanium dioxide. In step S2, the curing agent is triethylenetetramine. In step S3, the photoinitiator is isopropylthioxanthone.

[0035] The present invention has the following beneficial effects:

[0036] 1. For the electronic-grade epoxy resin composition prepared by the present invention, using bisphenol A epoxy resin as the base material, modified fillers and modified toughened polyester as reinforcing materials, and curing agents, photoinitiators and auxiliary additives as auxiliaries, and storing it in a sealed manner, an epoxy resin composition is obtained. This epoxy resin composition can be cured by ultraviolet light and heat to achieve the encapsulation of electronic products. By using polyethylene glycol and isocyanate groups as raw materials, dipentaerythritol as a chain extender, and 2-hydroxyisopropyl methacrylate and γ-aminopropyltriethoxysilane as end-capping agents, a modified toughened polyester with terminal siloxy groups and terminal olefins is prepared. The introduction of polyethylene glycol and dipentaerythritol increases the flexibility of the molecular chain, reduces the brittleness of the epoxy resin, and improves the toughness of the electronic-grade epoxy resin composition. When the siloxy groups of γ-aminopropyltriethoxysilane meet the water vapor in the external environment, the siloxane bonds are hydrolyzed into silanols, and the silanols can react with polar groups such as hydroxyl groups on the surface of inorganic substances such as modified fillers, improving the interfacial bonding force between the modified fillers and the resin matrix. At the same time, the hydrolysis of the siloxane bonds can form a cured coating on the surface of the epoxy resin composition, further improving the mechanical properties of the epoxy resin composition.

[0037] 2. For the electronic-grade epoxy resin composition prepared by the present invention, nano boron nitride is washed to remove dirt, exposing more reaction sites, and then modified with a silane coupling agent containing epoxy groups and multiple fluorine atoms to obtain fluorinated nano boron nitride. By catalytically reacting γ-aminopropyltriethoxysilane, an octahedral modified polysiloxane with hydrolysis and condensation of multiple silane coupling agent siloxane bonds is obtained. Using the modified polysiloxane as the skeleton and adding fluorinated nano boron nitride, a nucleophilic reaction occurs between the epoxy groups on the surface of the fluorinated nano boron nitride and the amino groups of the modified polysiloxane to obtain a skeleton with a surface coated with fluorinated nano boron nitride. The epoxy groups on the surface of the fluorinated nano boron nitride and the amino groups of the modified polysiloxane form covalent bonds through a nucleophilic reaction, enhancing the binding force between the fluorinated nano boron nitride and the polysiloxane skeleton. At the same time, the introduction of fluorine groups improves the dispersion of the nano filler in the epoxy resin, avoiding agglomeration. Fluorinated nano boron nitride itself has high thermal conductivity and thermal stability, which can effectively disperse the heat generated during the use of electronic products, reducing local overheating. At the same time, the fluorine groups on the surface of the fluorinated nano boron nitride can reduce the dielectric constant of the resin composition.

[0038] 3. The electronic-grade epoxy resin composition prepared by the present invention introduces a large number of silicon-oxygen bond structures through modified fillers and modified toughening polyesters. The silicon-oxygen bond has a very high bond energy, and this high bond energy enables the silicon-oxygen bond to maintain the structural stability at high temperatures and is not easily broken. When the silicon-oxygen bond is introduced into the epoxy resin composition, its thermal stability can be improved. By introducing a modified toughening polyester with terminal siloxy groups and terminal olefins, an electronic-grade epoxy resin composition with a dual-curing mechanism is prepared. Under the action of a photoinitiator, the epoxy resin mixture and the curing agent mixture undergo a photopolymerization reaction under the action of an ultraviolet lamp to form a crosslinked network, enhancing the mechanical properties of the epoxy resin composition. After ultraviolet curing, further thermal curing is carried out. By heating, triethylenetetramine is activated, further initiating a deep crosslinking reaction between epoxy groups and amino groups, improving the mechanical properties of the epoxy resin composition. Ultraviolet curing enables the surface or thin layer to be quickly cured and shaped, while thermal curing can penetrate into the deep layer of complex structures to ensure the consistency of the overall performance of the epoxy resin composition. Detailed Embodiments

[0039] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0040] The bisphenol A epoxy resin used in the present invention is purchased from Shanghai Kayin Chemical Co., Ltd., with the brand number 604.

[0041] Example 1

[0042] This example provides a preparation method for an electronic-grade epoxy resin composition, including the following steps:

[0043] S1. Prepare fluorinated nano boron nitride

[0044] Weigh: 100 g of nano boron nitride, 500 mL of deionized water, and 500 mL of ethanol, place them in a reaction kettle, heat up to 40 °C, ultrasonicate for 20 min, and dry to obtain pretreated nano boron nitride;

[0045] Weigh: 80 g of pretreated nano boron nitride, 1000 mL of ethanol, and 100 mL of deionized water, place them in a reaction kettle, heat up to 40 °C, add 50 g of γ-glycidoxypropyltrimethoxysilane and 30 g of perfluorooctyltrimethoxysilane, keep the temperature for reaction for 1 h. After the reaction is completed, carry out suction filtration. The filter cake is washed once with deionized water and ethanol, transferred to a drying oven at 50 °C, and dried to constant weight to obtain fluorinated nano boron nitride.

[0046] S2. Prepare modified fillers

[0047] Weigh: 30 mL of 75 wt% tetramethylammonium hydroxide solution, 5000 mL of deionized water, and 180 mL of propanol and place them in a reaction kettle. Stir for 10 min, add 1000 g of γ-aminopropyltriethoxysilane, heat up to 40 °C, and keep the reaction for 4 h. After the reaction is completed, wait for the reaction system to cool to room temperature, add tetrahydrofuran to the reaction solution to precipitate a solid, filter by suction, wash the filter cake once with deionized water, transfer it to a drying oven at 70 °C, and dry to constant weight to obtain modified polysiloxane;

[0048] Weigh: 150 mL of deionized water, 150 mL of isopropanol, and 15 g of fluorinated nano boron nitride and place them in a reaction kettle. Add 0.5 mol / mL sodium hydroxide solution to adjust the pH to 9.3, add 70 g of modified polysiloxane, heat up to 40 °C, and keep the reaction for 3 h. After the reaction is completed, filter by suction, wash the filter cake once with deionized water and ethanol, transfer it to a drying oven at 70 °C, and dry to constant weight to obtain modified filler.

[0049] S3. Prepare modified toughened polyester

[0050] Mix 2-hydroxyisopropyl methacrylate and γ-aminopropyltriethoxysilane evenly according to the mass ratio of 2:1 to obtain a capping agent for standby;

[0051] Weigh: 100 g of polyethylene glycol, 5 g of dibutyltin dilaurate, and 2000 mL of tetrahydrofuran and place them in a reaction kettle protected by a nitrogen atmosphere. Heat up to 45 °C, stir for 20 min, add isophorone diisocyanate according to 2.1 times the total molar amount of polyethylene glycol hydroxyl groups, keep the reaction for 1 h, add 8 g of dipentaerythritol to the reaction kettle, keep the reaction for 0.5 h, add 100 g of the capping agent, and keep the reaction for 1 h. After the reaction is completed, heat up to 70 °C and distill under reduced pressure until no liquid is collected to obtain modified toughened polyester.

[0052] S4. Prepare epoxy resin composition

[0053] Mix butanediol diglycidyl ether, 1-ethyl-3-methylimidazolium tetrafluoroborate, polydimethylsiloxane, and phthalocyanine blue evenly according to the mass ratio of 5:2:1:2 to obtain an auxiliary additive for standby;

[0054] Weigh by weight: 30 parts of bisphenol A epoxy resin, 35 parts of modified filler, 15 parts of modified toughened polyester, 5 parts of triethylenetetramine, 1 part of isopropylthioxanthone, and 1 part of auxiliary additive for standby;

[0055] Place bisphenol A epoxy resin and the auxiliary additive in a vacuum stirring and defoaming machine, mix evenly, and carry out vacuum defoaming to obtain an epoxy resin mixture;

[0056] Put triethylenetetramine, modified filler and modified toughened polyester into a vacuum stirring and degassing machine, mix evenly, and carry out vacuum degassing to obtain a curing agent mixture;

[0057] Mix the epoxy resin mixture, isopropylthioxanthone and the curing agent mixture evenly, and store it sealed to obtain an epoxy resin composition.

[0058] Example 2

[0059] This example provides a preparation method of an electronic-grade epoxy resin composition, including the following steps:

[0060] S1. Prepare fluorinated nano boron nitride

[0061] Weigh: 125 g of nano boron nitride, 600 mL of deionized water and 600 mL of ethanol, place them in a reaction kettle, heat up to 45 °C, ultrasonicate for 25 min, and dry to obtain pretreated nano boron nitride;

[0062] Weigh: 100 g of pretreated nano boron nitride, 1100 mL of ethanol and 125 mL of deionized water, place them in a reaction kettle, heat up to 45 °C, add 65 g of γ-glycidoxypropyltrimethoxysilane and 35 g of perfluorooctyltrimethoxysilane, keep the temperature for reaction for 1.5 h. After the reaction is completed, carry out suction filtration, wash the filter cake with deionized water and ethanol twice, transfer it to a drying oven at 55 °C, and dry to constant weight to obtain fluorinated nano boron nitride.

[0063] S2. Prepare modified filler

[0064] Weigh: 40 mL of 80 wt% tetramethylammonium hydroxide solution, 5500 mL of deionized water and 190 mL of propanol, place them in a reaction kettle for 5 h. After the reaction is completed, wait for the reaction system to cool to room temperature, add tetrahydrofuran to the reaction solution to precipitate solids, carry out suction filtration, wash the filter cake with deionized water twice, transfer it to a drying oven at 75 °C, and dry to constant weight to obtain modified polysiloxane;

[0065] Weigh: 170 mL of deionized water, 170 mL of isopropanol and 17 g of fluorinated nano boron nitride, place them in a reaction kettle, add 1.0 mol / mL sodium hydroxide solution to adjust the pH = 9.4, add 85 g of modified polysiloxane, heat up to 45 °C, keep the temperature for reaction for 3.5 h. After the reaction is completed, carry out suction filtration, wash the filter cake with deionized water and ethanol twice, transfer it to a drying oven at 75 °C, and dry to constant weight to obtain modified filler.

[0066] S3. Prepare modified toughened polyester

[0067] Mix 2-hydroxyisopropyl methacrylate and γ-aminopropyltriethoxysilane evenly according to the mass ratio of 2:1 to obtain a capping agent for standby;

[0068] Weigh: 125 g of polyethylene glycol, 7 g of dibutyltin dilaurate and 2250 mL of tetrahydrofuran and place them in a reaction kettle protected by a nitrogen atmosphere. Heat up to 50 °C and stir for 20 - 30 min. Add isophorone diisocyanate according to 2.1 times the total molar amount of the hydroxyl groups of polyethylene glycol, and keep the temperature for reaction for 1.5 h. Add 100 g of dipentaerythritol to the reaction kettle, keep the temperature for reaction for 1 h, add 110 g of a capping agent, and keep the temperature for reaction for 1.5 h. After the reaction is completed, heat up to 75 °C and distill under reduced pressure until no liquid is collected, obtaining a modified and toughened polyester.

[0069] S4. Prepare an epoxy resin composition

[0070] Mix butanediol diglycidyl ether, 1 - ethyl - 3 - methylimidazolium tetrafluoroborate, polydimethylsiloxane and phthalocyanine blue evenly according to a mass ratio of 5:2:1:2 to obtain an auxiliary additive for standby.

[0071] Weigh by weight: 34 parts of bisphenol A epoxy resin, 37 parts of modified filler, 17 parts of modified and toughened polyester, 7 parts of triethylenetetramine, 1.5 parts of isopropylthioxanthone and 3 parts of auxiliary additive for standby.

[0072] Place bisphenol A epoxy resin and the auxiliary additive in a vacuum stirring and defoaming machine, mix evenly, and conduct vacuum defoaming to obtain an epoxy resin mixture.

[0073] Place triethylenetetramine, modified filler and modified and toughened polyester in a vacuum stirring and defoaming machine, mix evenly, and conduct vacuum defoaming to obtain a curing agent mixture.

[0074] Mix the epoxy resin mixture, isopropylthioxanthone and the curing agent mixture evenly, seal and store to obtain an epoxy resin composition.

[0075] Example 3

[0076] This example provides a preparation method of an electronic - grade epoxy resin composition, including the following steps:

[0077] S1. Prepare fluorinated nano - boron nitride

[0078] Weigh: 150 g of nano - boron nitride, 700 mL of deionized water and 700 mL of ethanol, place them in a reaction kettle, heat up to 50 °C, ultrasonicate for 30 min, and dry to obtain pretreated nano - boron nitride.

[0079] Weigh: 120 g of pretreated nano boron nitride, 1200 mL of ethanol and 150 mL of deionized water are placed in a reaction kettle, heated to 50 °C, 80 g of γ-glycidoxypropyltrimethoxysilane and 40 g of perfluorooctyltrimethoxysilane are added, and the reaction is carried out under insulation for 2 h. After the reaction is completed, filtration is carried out, and the filter cake is washed twice with deionized water and ethanol, then transferred to a drying oven at 60 °C and dried to constant weight to obtain fluorinated nano boron nitride.

[0080] S2. Preparation of modified filler

[0081] Weigh: 50 mL of 80 wt% tetramethylammonium hydroxide solution, 6200 mL of deionized water and 200 mL of propanol are placed in a reaction kettle, stirred for 150 min, 1100 g of γ-aminopropyltriethoxysilane is added, heated to 50 °C, and the reaction is carried out under insulation for 6 h. After the reaction is completed, when the reaction system cools to room temperature, tetrahydrofuran is added to the reaction solution to precipitate a solid. Filtration is carried out, and the filter cake is washed twice with deionized water, then transferred to a drying oven at 80 °C and dried to constant weight to obtain modified polysiloxane;

[0082] Weigh: 200 mL of deionized water, 200 mL of isopropanol and 20 g of fluorinated nano boron nitride are placed in a reaction kettle, the pH is adjusted to 9.5 with 1.0 mol / mL sodium hydroxide solution, 100 g of modified polysiloxane is added, heated to 50 °C, and the reaction is carried out under insulation for h. After the reaction is completed, filtration is carried out, and the filter cake is washed twice with deionized water and ethanol, then transferred to a drying oven at 80 °C and dried to constant weight to obtain modified filler.

[0083] S3. Preparation of modified toughened polyester

[0084] Mix 2-hydroxyisopropyl methacrylate and γ-aminopropyltriethoxysilane evenly according to the mass ratio of 2:1 to obtain a capping agent for standby;

[0085] Weigh: 150 g of polyethylene glycol, 10 g of dibutyltin dilaurate and 2500 mL of tetrahydrofuran are placed in a reaction kettle protected by a nitrogen atmosphere, heated to 55 °C, stirred for 30 min, isophorone diisocyanate is added according to 2.1 times the total molar amount of polyethylene glycol hydroxyl groups, and the reaction is carried out under insulation for 2 h. 120 g of dipentaerythritol is added to the reaction kettle, and the reaction is carried out under insulation for 1 h. 120 g of capping agent is added, and the reaction is carried out under insulation for 2 h. After the reaction is completed, the temperature is raised to 80 °C, and vacuum distillation is carried out until no liquid is collected to obtain modified toughened polyester.

[0086] S4. Preparation of epoxy resin composition

[0087] Mix butanediol diglycidyl ether, 1-ethyl-3-methylimidazolium tetrafluoroborate, polydimethylsiloxane and phthalocyanine blue evenly according to the mass ratio of 5:2:1:2 to obtain an auxiliary additive for standby;

[0088] Weigh by parts by weight: 36 parts of bisphenol A epoxy resin, 40 parts of modified filler, 20 parts of modified toughened polyester, 10 parts of triethylenetetramine, 2 parts of isopropyl thioxanthone, and 6 parts of auxiliary additive, and set aside;

[0089] Place the bisphenol A epoxy resin and the auxiliary additive in a vacuum stirring and defoaming machine, mix evenly, and perform vacuum defoaming to obtain an epoxy resin mixture;

[0090] Place the triethylenetetramine, the modified filler, and the modified toughened polyester in a vacuum stirring and defoaming machine, mix evenly, and perform vacuum defoaming to obtain a curing agent mixture;

[0091] Mix the epoxy resin mixture, isopropyl thioxanthone, and the curing agent mixture evenly, seal and store to obtain an epoxy resin composition.

[0092] Comparative Example 1

[0093] The difference between this comparative example and Example 2 is that the step of preparing fluorinated nano-boron nitride in step S1 is cancelled, and pretreated nano-boron nitride is used to replace fluorinated nano-boron nitride in equal amount during the process of preparing the modified filler in step S2.

[0094] Comparative Example 2

[0095] The difference between this comparative example and Example 2 is that the step of preparing the modified filler in step S2 is cancelled, and the modified filler is not added during the process of preparing the epoxy resin composition in step S4.

[0096] Comparative Example 3

[0097] The difference between this comparative example and Example 2 is that γ-aminopropyltriethoxysilane is not added when preparing the end-capping agent in step S3, and 2-hydroxyisopropyl methacrylate is used to replace the end-capping agent in equal amount during the process of preparing the modified toughened polyester.

[0098] Performance test:

[0099] Refer to the standard GB / T 31838.1-2015 "Solid insulating materials - Dielectric and resistive properties - Part 1: General" to test the dielectric constant and volume resistivity of the cured specimens of the epoxy resin compositions prepared in Examples 1-3 and Comparative Examples 1-3;

[0100] Refer to the standard GB / T 1040.1-2006 "Plastics - Determination of tensile properties - Part 1: General Principles" to test the tensile strength and elongation at break of the cured specimens of the epoxy resin compositions prepared in Examples 1-3 and Comparative Examples 1-3;

[0101] Refer to the standard GB / T 29313-2012 "Test Method for Thermal Conductivity of Electrical Insulating Materials", and conduct thermal conductivity tests on the cured specimens of the epoxy resin compositions prepared in Examples 1-3 and Comparative Examples 1-3;

[0102] Refer to the standard GB / T 36800.2-2018 "Plastics - Thermomechanical Analysis (TMA) - Part 2: Determination of Linear Thermal Expansion Coefficient and Glass Transition Temperature", and conduct linear thermal expansion coefficient tests on the cured specimens of the epoxy resin compositions prepared in Examples 1-3 and Comparative Examples 1-3. The specific data are shown in Table 1;

[0103] Refer to the high-temperature and high-humidity environment setting of the standard GB / T 32368-2015 "Test Method for High Temperature and High Humidity Aging of Adhesive Tapes", and conduct high-temperature resistance tests on the cured specimens of the epoxy resin compositions prepared in Examples 1-3 and Comparative Examples 1-3. Refer to the standard GB / T 31838.1-2015 "Dielectric and Resistive Properties of Solid Insulating Materials - Part 1: General", and conduct dielectric constant and volume resistivity tests on the cured specimens of the epoxy resin compositions prepared in Examples 1-3 and Comparative Examples 1-3. Refer to the standard GB / T 1040.1-2006 "Plastics - Determination of Tensile Properties - Part 1: General Principles", and conduct tensile strength and elongation at break tests on the cured specimens of the epoxy resin compositions prepared in Examples 1-3 and Comparative Examples 1-3. The specific data are shown in Table 2

[0104] Table 1 - Performance Test Data Sheet of Each Specimen before High Temperature and High Humidity Treatment

[0105]

[0106]

[0107] Table 2 - Performance Test Data Sheet of Each Specimen after High Temperature and High Humidity Treatment

[0108]

[0109] Data Analysis:

[0110] By comparing and analyzing the data in Table 1 and Table 2, the dielectric constant of the cured specimen of the epoxy resin composition prepared in the present invention is 3.01 F·m -1 、the volume resistivity is 2.25×10 13 Ω·m, the tensile strength is 87.01 MPa, the elongation at break is 15.41%, and the thermal conductivity is 2.74 W·(m·K) -1 , and the linear thermal expansion coefficient is only 0.27 W·(m·K) -1 , and all the data are better than those of the comparative examples;

[0111] After the high-temperature performance test, the dielectric constant of the cured specimen of the epoxy resin composition prepared by the present invention is 3.15 F·m -1 , the volume resistivity is 2.14×10 13 Ω·m, the tensile strength is 86.51 MPa, and the elongation at break is 14.35%, and all data are better than those of the comparative example;

[0112] Data description:

[0113] By comparing and analyzing the data of Comparative Example 1 and Example 2, it can be seen that the volume resistivity, tensile strength, elongation at break and thermal conductivity of the epoxy resin composition prepared by the present invention are reduced, and the linear thermal expansion coefficient and dielectric constant are increased; after the high-temperature performance test, the dielectric constant and volume resistivity of the cured specimen of the epoxy resin composition prepared by the present invention are increased, and the tensile strength and elongation at break are reduced, indicating that in the process of preparing the epoxy resin composition of the present invention, by washing the nano boron nitride to remove dirt and exposing more reaction sites, and then modifying it with a silane coupling agent containing epoxy groups and multiple fluorine atoms, fluorinated nano boron nitride is obtained. The introduction of fluorinated groups improves the dispersion of nano fillers in epoxy resin and avoids agglomeration. Fluorinated nano boron nitride itself has high thermal conductivity and thermal stability, which can effectively disperse the heat generated during the use of electronic products and reduce local overheating. At the same time, the fluorinated groups on the surface of fluorinated nano boron nitride can reduce the dielectric constant of the resin composition.

[0114] By comparing and analyzing the data of Comparative Example 2 and Example 2, it can be seen that the volume resistivity, tensile strength, elongation at break and thermal conductivity of the epoxy resin composition prepared by the present invention are reduced, and the linear thermal expansion coefficient and dielectric constant are increased; after the high-temperature performance test, the dielectric constant and volume resistivity of the cured specimen of the epoxy resin composition prepared by the present invention are increased, and the tensile strength and elongation at break are reduced, indicating that in the process of preparing the epoxy resin composition of the present invention, by catalyzing γ-aminopropyltriethoxysilane, an octahedral modified polysiloxane with hydrolysis and condensation of multiple silane coupling agent siloxane bonds is obtained. Using the modified polysiloxane as the skeleton and adding fluorinated nano boron nitride, a nucleophilic reaction occurs between the epoxy groups on the surface of fluorinated nano boron nitride and the amino groups of the modified polysiloxane to obtain a skeleton coated with fluorinated nano boron nitride on the surface. The epoxy groups on the surface of fluorinated nano boron nitride and the amino groups of the modified polysiloxane form covalent bonds through nucleophilic reaction, enhancing the binding force between fluorinated nano boron nitride and the polysiloxane skeleton.

[0115] By comparing and analyzing the data of Comparative Example 3 and Example 2, it can be seen that the volume resistivity, tensile strength and elongation at break of the epoxy resin composition prepared by the present invention are reduced, and the linear thermal expansion coefficient and dielectric constant are increased; after the high-temperature performance test, the dielectric constant and volume resistivity of the cured specimen of the epoxy resin composition prepared by the present invention are increased, and the tensile strength and elongation at break are reduced, indicating that in the process of preparing the epoxy resin composition of the present invention, by using polyethylene glycol and isocyanate group as raw materials, dipentaerythritol as a chain extender, and 2-hydroxyisopropyl methacrylate and γ-aminopropyltriethoxysilane as end-capping agents, a modified toughened polyester with terminal siloxy groups and terminal olefins is prepared. The introduction of polyethylene glycol and dipentaerythritol increases the flexibility of the molecular chain, reduces the brittleness of the epoxy resin, and improves the impact resistance and crack resistance of the electronic-grade epoxy resin composition. When the siloxy group of γ-aminopropyltriethoxysilane meets the water vapor in the external environment, the siloxane bond is hydrolyzed into silanol, and the silanol can react with polar groups such as hydroxyl groups on the surface of inorganic substances such as modified fillers, improving the interfacial bonding force between the modified filler and the resin matrix. At the same time, the hydrolysis of the siloxane bond can form a cured coating on the surface of the epoxy resin composition, further improving the mechanical properties of the epoxy resin composition.

[0116] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the present invention to the specific embodiments described. Obviously, many modifications and variations can be made according to the content of this specification. These embodiments are selected and specifically described in this specification to better explain the principle and practical application of the present invention, so that those skilled in the art in the relevant technical field can well understand and utilize the present invention. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. An electronic grade epoxy resin composition, characterized in that: The invention comprises the following raw materials in parts by weight: 30-36 parts of epoxy resin, 35-40 parts of modified filler, 15-20 parts of modified toughened polyester, 5-10 parts of curing agent, 1-2 parts of photoinitiator and 1-6 parts of auxiliary additives; The modified filler is obtained by the following method: A1. Place tetramethylammonium hydroxide solution, deionized water and propanol in a reaction kettle, stir for 10-15 minutes, add γ-aminopropyltriethoxysilane, heat to 40-50°C, keep warm for 4-6 hours, and post-treat to obtain modified polysiloxane; A2. Deionized water, isopropanol and fluorinated nano-boron nitride are placed in a reaction kettle, sodium hydroxide solution is added to adjust the pH to 9±0.5, modified polysiloxane is added, the temperature is raised to 40-50° C., the reaction is kept warm for 3-4 hours, and the modified filler is obtained by post-treatment.

2. An electronic grade epoxy resin composition according to claim 1, characterized in that: In step A1, the concentration of the tetramethylammonium hydroxide solution is 75-80wt%, and the usage ratio of the octamethylammonium hydroxide solution, deionized water, propanol and γ-aminopropyltriethoxysilane is 3-5mL:500-620mL:18-20mL:100-110g; in step A2, the concentration of the sodium hydroxide solution is 0.5-1.0mol / mL, and the usage ratio of the deionized water, isopropanol, fluorinated nano-boron nitride and modified polysiloxane is 15-20mL:15-20mL:1.5-2g:7-10g.

3. An electronic grade epoxy resin composition according to claim 1, characterized in that: The fluorinated nano boron nitride is obtained by the following preparation method: B1. Place nano-boron nitride, deionized water and ethanol in a reaction kettle, heat to 40-50°C, perform ultrasonic treatment for 20-30 minutes, and dry to obtain pretreated nano-boron nitride; B2. Place the pretreated nano-boron nitride, ethanol and deionized water in a reaction kettle, heat to 40-50°C, add γ-glycidyloxypropyltrimethoxysilane and perfluorooctyltrimethoxysilane, keep the temperature for 1-2 hours, and post-treat to obtain fluorinated nano-boron nitride.

4. An electronic grade epoxy resin composition according to claim 3, characterized in that: In step B1, the dosage ratio of the nano boron carbide, deionized water and ethanol is 10-15g:50-70mL:50-70mL. In step B2, the dosage ratio of the pretreated nano boron nitride, ethanol, deionized water, perfluorooctyltrimethoxysilane and γ-glycidyloxypropyltrimethoxysilane is 8-12g:100-120mL:10-15mL:5-8g:3-4.

5. An electronic grade epoxy resin composition according to claim 1, characterized in that: The preparation method of the modified toughened polyester comprises the following steps: placing polyethylene glycol, dibutyltin dilaurate and tetrahydrofuran in a reactor protected by a nitrogen atmosphere, heating to 45-55° C., stirring for 20-30 minutes, adding isophorone diisocyanate, and reacting at the temperature for 1-2 hours, adding a chain extender to the reactor, reacting at the temperature for 0.5-1 hour, adding a capping agent, reacting at the temperature for 1-2 hours, and post-treating to obtain the modified toughened polyester.

6. An electronic grade epoxy resin composition according to claim 5, characterized in that: The dosage ratio of the polyethylene glycol, tetrahydrofuran, dibutyltin dilaurate, chain extender and end capping agent is 10-15g:200-250mL:0.5-1g:3.5-5.5g:4-6g, the chain extender is dipentaerythritol, the end capping agent is composed of 2-hydroxyisopropyl methacrylate and γ-aminopropyltriethoxysilane in a mass ratio of 2:1, and the dosage of the isophorone diisocyanate is 2.1 times the total molar amount of polyethylene glycol hydroxyl groups.

7. The method for preparing an electronic grade epoxy resin composition according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1, placing the epoxy resin and auxiliary additives in a vacuum stirring degassing machine, mixing them evenly, and vacuum degassing to obtain an epoxy resin mixture; S2, placing the curing agent, modified filler and modified toughened polyester in a vacuum stirring degassing machine, mixing them evenly, and vacuum degassing to obtain a curing agent mixture; S3, mixing the epoxy resin mixture, the photoinitiator and the curing agent mixture evenly, and sealing and storing them to obtain an epoxy resin composition.

8. The method for preparing an electronic grade epoxy resin composition according to claim 7, characterized in that: In step S1, the epoxy resin is bisphenol A epoxy resin, the auxiliary additives are composed of a diluent, an antistatic agent, a defoaming agent and a pigment in a mass ratio of 5:2:1:2, the diluent is one or more of dibutyl phthalate, butanediol diglycidyl ether and glycidyl 12-14 alkyl ether, the antistatic agent is one or two of 1-ethyl-3-methylimidazole tetrafluoroborate and 1-butyl-3-methylimidazole hexafluorophosphate, the defoaming agent is polydimethylsiloxane, and the pigment is one or two of phthalocyanine blue and titanium dioxide; in step S2, the curing agent is triethylenetetramine; in step S3, the photoinitiator is isopropylthioxanthone.

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