Electronic-grade amine epoxy resin and preparation method thereof

Abstract

The invention discloses electronic-grade amine epoxy resin and a preparation method thereof, and belongs to the field of epoxy resin preparation. Aiming at the problems of more by-products and poor performance of the existing epoxy resin preparation, the invention provides the preparation method of the electronic-grade amine epoxy resin, which comprises the following steps: synthesizing a chlorohydrin ether intermediate from p-aminophenol and epichlorohydrin; meanwhile, a catalyst is added in the ring-opening reaction stage; carrying out removal of epoxy chloropropane; alkali metal hydroxide is added for a dehydrochlorination reaction, and a target product is generated in a closed-loop manner; and washing to remove excessive alkali metal hydroxides, and reacting to generate chlorides to obtain the electronic-grade amine epoxy resin. According to the method, the ring opening speed of phenolic hydroxyl is remarkably increased through the catalyst, so that epoxy chloropropane is fully reacted, and residues are reduced; according to the method, excessive epoxy chloropropane is removed, so that side reaction of epoxy chloropropane in a ring closing stage is avoided, generation of by-products is reduced to the greatest extent, operation is simple, and high-quality epoxy resin can be generated.

Description

Technical Field

[0001] The present invention belongs to the technical field of epoxy resin preparation, and more specifically, relates to an electronic-grade amine epoxy resin and a preparation method thereof. Background Art

[0002] With the rapid development of the electronics industry, the demand for high-performance electronic materials is increasing day by day. As an important thermosetting material, epoxy resin has a wide range of applications in electronic packaging, copper-clad laminates, etc. Electronic-grade epoxy resin needs to have excellent electrical properties, mechanical properties, thermal properties, etc. In the prior art, epoxy resin is synthesized by reacting p-aminophenol with epichlorohydrin under alkaline conditions. Due to its unique molecular structure, aminophenol epoxy resin has the characteristics of good heat resistance and low viscosity. At the same time, the presence of amino groups also improves the flexibility, adhesiveness and other properties of the resin, and is mainly used in the fields of electronic glue, composite materials and copper-clad laminates. However, this method has some problems. For example, there are many side reactions during the reaction, resulting in low product purity. Under alkaline conditions, epichlorohydrin is prone to hydrolysis side reactions, generating impurities such as glycerol, which affect the performance of the final epoxy resin; or the process is cumbersome, making the preparation cost high.

[0003] Corresponding modifications have also been made to the above problems. For example, Chinese Patent Application No. CN202111073642.0, with a publication date of November 26, 2021, discloses a method for synthesizing a tetrafunctional glycidylamine epoxy resin, including: 1) Ring-opening reaction, synthesizing a chlorohydrin ether intermediate from 4,4'-diaminodiphenylmethane and epichlorohydrin; water is used as a polar catalyst; 2) Ring-closing reaction, adding an alkali metal hydroxide for dehydrochlorination reaction to form the target product by ring-closing; 3) Washing and refining, extracting the organic phase with water, washing to remove excessive alkali metal hydroxide and chlorides generated by the reaction, and obtaining the product by vacuum distillation to remove excessive epichlorohydrin. The disadvantages of this patent are: Although alcohol solvents are not used in the process, there are still problems such as insufficient reaction of epichlorohydrin during the whole process, resulting in deficiencies in the performance of the final product.

[0004] Another example is Chinese Patent Application No. CN202411184979.2, with a publication date of October 1, 2024. This patent discloses a production process of a new type of electronic-grade liquid epoxy. Pre-polymerization (etherification): Bisphenol A is dissolved in epichlorohydrin, nitrogen is introduced, and liquid alkali (50%) is added at normal pressure for etherification reaction; the specific process of the pre-reaction (etherification) is: Pump the liquid alkali in the tank area into the corresponding liquid alkali high-level tank in the production workshop through a pipeline for standby; The raw material bisphenol A is transported to the workshop high-level tank by air flow of the tank truck. The disadvantages of this patent are: Although the overall automation degree is relatively high, the overall operation is cumbersome, time-consuming and inefficient. Summary of the Invention

[0005] 1. Problems to be Solved Aiming at the problems of many by-products and poor performance in the preparation of existing epoxy resins, the present invention provides an electronic-grade amine epoxy resin and a preparation method thereof. By using a catalyst, the present invention significantly accelerates the ring-opening rate of phenolic hydroxyl groups, enabling epichlorohydrin to react fully and reducing the residue of epichlorohydrin. By removing the excess epichlorohydrin before the ring-closing reaction, the present invention further avoids side reactions of epichlorohydrin under the action of alkali metal hydroxides during the ring-closing stage, minimizing the generation of by-products to the greatest extent. The operation is simple, and high-quality epoxy resins can be produced.

[0006] 2. Technical Solutions To solve the above problems, the present invention adopts the following technical solutions.

[0007] A preparation method of an electronic-grade amine epoxy resin includes the following steps: S1: Ring-opening reaction: p-aminophenol and epichlorohydrin are synthesized into a chlorohydrin ether intermediate; meanwhile, a catalyst for promoting the reaction of epichlorohydrin is added during the ring-opening reaction stage; the mass ratio of the catalyst to p-aminophenol is (0.005% - 0.15%):1; S2: After the ring-opening reaction is completed, epichlorohydrin is removed; S3: Ring-closing reaction: By adding an organic solvent and an alkali metal hydroxide to the system after the ring-opening reaction is completed for dehydrochlorination reaction, the target product is formed by ring-closing; among them, the addition of the alkali metal hydroxide is divided into two additions: the first time, an aqueous sodium hydroxide solution with a dosage of 2 - 2.5 times that of p-aminophenol is added dropwise, the reaction time is 2 - 6 hours, and the reaction temperature is controlled at 40 - 60°C; the second time, an aqueous sodium hydroxide solution with a dosage of 0.2 - 0.25 times that of p-aminophenol is added; the reaction is carried out for 2 - 4 hours, and the reaction temperature is controlled at 50 - 80°C; S4: Wash to remove the excessive alkali metal hydroxide and the chlorides generated by the reaction, and finally obtain the electronic-grade amine epoxy resin.

[0008] Furthermore, the catalyst in step S1 is one of benzyltriethylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium chloride, tetrabutylammonium hydrogensulfate, and dodecyltrimethylammonium chloride. Furthermore, when carrying out the ring-opening reaction, the addition of p-aminophenol is as follows: p-aminophenol is divided into several portions, and each portion of p-aminophenol is added to epichlorohydrin in sequence for reaction.

[0009] Furthermore, the removal of epichlorohydrin in step S2 is specifically carried out under the conditions of a temperature of 60°C - 80°C, a pressure of less than 1 Kpa, and a time of 2 - 4 h for the recovery of epichlorohydrin.

[0010] Further, the organic solvent is toluene or MIBK or isopropanol, and the amount of the organic solvent is 3-7 times the amount of p-aminophenol.

[0011] Further, in the step S3, the concentration of the alkali metal hydroxide is 20% - 50%; and the alkali metal hydroxide is a liquid alkali metal hydroxide or a solid alkali metal hydroxide.

[0012] Further, the step S4 includes two washings to remove the excessive alkali metal hydroxide and the chlorides generated by the reaction; specifically, it includes the following steps: S41: The first washing removes the excessive alkali metal hydroxide and the chlorides generated by the reaction, and after liquid separation, a refining reaction is carried out again by adding an alkali metal hydroxide to further reduce the chlorine content; S42: The second time, water is added to wash the excessive alkali metal hydroxide and the chlorides generated by the reaction, and then the pH of the system after the closed-loop reaction is adjusted to neutral, and the organic solvent is removed to obtain an electronic-grade amine epoxy resin.

[0013] An electronic-grade amine epoxy resin is prepared by using the preparation method of an electronic-grade amine epoxy resin described in any one of the above.

[0014] 3. Beneficial effects Compared with the prior art, the beneficial effects of the present invention are as follows: (1) Firstly, in the present invention, a catalyst is added in the ring-opening reaction stage. The catalyst significantly accelerates the ring-opening speed of the phenolic hydroxyl group, enabling epichlorohydrin to fully react, improving the reaction efficiency while reducing the residue of epichlorohydrin, and to a certain extent reducing the generation of by-products in the closed-loop stage; then, before the closed-loop reaction, the excess epichlorohydrin is removed, thereby further avoiding the side reaction of epichlorohydrin under the action of alkali metal hydroxide in the closed-loop stage, minimizing the generation of by-products. By-products may affect the performance of epoxy resin, and timely removal can avoid these adverse effects, thus ensuring the quality of the final product; the whole process is simple to operate, without the need to add additional cumbersome process technologies. Only by adding the corresponding catalyst and removing the excess epichlorohydrin can high-quality epoxy resin be produced; (2) The present invention uses an ammonium salt catalyst to accelerate the combination of epichlorohydrin and phenolic hydroxyl group, promoting the ring-opening reaction. And the ammonium salt catalyst does not introduce the generation of unnecessary products, ensuring the purity of the chlorohydrin ether intermediate; and the dosage of the catalyst is limited to avoid waste of cost caused by using too much catalyst; too little catalyst cannot achieve the effect of sufficient reaction; at the same time, since a large amount of heat is released during the ring-opening reaction, p-aminophenol is added in batches to epichlorohydrin to slow down the reaction heat release and ensure the safety of the preparation process; (3) In the present invention, by adding sodium hydroxide twice in the closed-loop stage, the self-polymerization of epoxy groups caused by high-concentration sodium hydroxide is avoided, and the product yield is increased. At the same time, after the closed-loop reaction, it undergoes multiple washings to remove excessive alkali metal hydroxides and chlorides generated by the reaction, effectively removing impurities and improving the purity and performance of the epoxy resin. At the same time, after the first washing, by adding alkali metal hydroxide again for the refining reaction, the chlorine content can be further reduced to ensure that the purity of the product meets the requirements of the electronic grade. Through washing and refining reactions, factors that are unfavorable to the stability of the epoxy resin can be removed, thereby improving the stability of the epoxy resin. Detailed implementation manners

[0015] The present invention will be further described below in conjunction with specific embodiments.

[0016] A preparation method of an electronic-grade amine-based epoxy resin includes the following steps: S1: Ring-opening reaction: p-aminophenol reacts with epichlorohydrin to synthesize a chlorohydrin ether intermediate; at the same time, a catalyst for promoting the reaction of epichlorohydrin is added during the ring-opening reaction stage. The ring-opening reaction is an exothermic reaction, and the reaction temperature is controlled at 40-60 °C, and the reaction time is 2-6 hours. The mass ratio of the catalyst to p-aminophenol is (0.005% - 0.15%):1; Specifically, in step S1, p-aminophenol and epichlorohydrin undergo the following reaction to synthesize a chlorohydrin ether intermediate:

[0017] The amino group can directly undergo a ring-opening reaction with epichlorohydrin. However, due to the slow ring-opening reaction rate of the phenolic hydroxyl group, it takes more than 20 hours to complete the ring-opening, which will lead to insufficient reaction of epichlorohydrin. The excess epichlorohydrin will generate new by-products in the subsequent reaction, thus affecting the performance of the finally prepared electronic-grade amine-based epoxy resin; at the same time, it prolongs the entire reaction time. Therefore, an innovation point of this application is to add a catalyst in the ring-opening reaction stage of step S1. Through the catalyst, the ring-opening reaction of p-aminophenol and epichlorohydrin forms a chlorohydrin ether intermediate, and the conversion rate of the entire reaction is more than 99%. This enables epichlorohydrin to react fully in this stage, reducing the residue of epichlorohydrin to a certain extent; at the same time, it speeds up the entire reaction efficiency, shortens the preparation cycle, and saves time costs; S2: After the ring-opening reaction is completed, epichlorohydrin is removed. Specifically, it should be noted that since the chlorohydrin ether intermediate generated by the ring-opening reaction will generate the target product in the subsequent closed-loop reaction stage, the specific reaction is as follows:

[0018] However, since there will still be excess epichlorohydrin remaining in the entire reaction system during the closed-loop stage, epichlorohydrin will undergo hydrolysis under alkaline conditions, and the final product is glycerol, which not only consumes raw materials but also dissolves in water, increasing the difficulty of water treatment. In addition, glycerol will react with epoxy resin or epichlorohydrin under alkaline conditions. The main reactions of epichlorohydrin hydrolysis are as follows:

[0019] Glycerol will react with epoxy resin or epichlorohydrin under alkaline conditions as follows:

[0020] where R is H or ; The above two-step reactions will consume the sodium hydroxide originally used in the closed-loop reaction stage, and an excessive amount of sodium hydroxide needs to be added to complete the closed-loop reaction. The increase in alkali concentration will further lead to the hydrolysis of epichlorohydrin and other side reactions. At the same time, the products in the ring-opening stage will undergo side reactions under the action of sodium hydroxide, resulting in the formation of non-hydrolyzable chlorine. The specific reactions are as follows:

[0021] Therefore, through the above analysis, it can be known that if epichlorohydrin is not removed during the closed-loop stage, it will greatly affect the purity and performance of the target product. Due to the increase in by-products and the consumption of excessive sodium hydroxide, it will also cause an increase in costs to a certain extent. Therefore, another major innovation point of this application is to remove epichlorohydrin before the closed-loop reaction stage, thereby further avoiding the hydrolysis of epichlorohydrin under the action of alkali metal hydroxides during the closed-loop stage and the occurrence of side reactions, minimizing the generation of by-products to the greatest extent. By-products may affect the performance of epoxy resin, and timely removal can avoid these adverse effects, thereby ensuring the quality of the final product.

[0022] S3: Closed-loop reaction: By adding an organic solvent and an alkali metal hydroxide to the system after the ring-opening reaction is completed to carry out a dehydrochlorination reaction, and closing the ring to generate the target product; S4: Wash to remove the excessive alkali metal hydroxide and the chlorides generated by the reaction, and finally obtain an electronic-grade amine-based epoxy resin.

[0023] In the prior art, usually the excess epichlorohydrin is removed after the closed-loop reaction is completed. This method cannot effectively solve the problem that due to the presence of epichlorohydrin during the closed-loop stage, hydrolysis occurs under alkaline conditions to produce side reactions and by-products, which will affect the performance and quality of the final product. And removing epichlorohydrin after the closed-loop reaction is completed increases the complexity of the subsequent steps, thereby lengthening the production cycle. In addition, since the by-products generated by epichlorohydrin during the closed-loop stage need to be further removed, it further increases the treatment difficulty and treatment cost.

[0024] Therefore, in the present application, firstly, a catalyst is added in the ring-opening reaction stage. The catalyst significantly accelerates the ring-opening rate of phenolic hydroxyl groups, enabling epichlorohydrin to fully react, improving the reaction efficiency while reducing the residue of epichlorohydrin, and to a certain extent reducing the generation of by-products in the ring-closure stage. Then, excess epichlorohydrin is removed before the ring-closure reaction, thereby further avoiding side reactions of epichlorohydrin under the action of alkali metal hydroxides in the ring-closure stage, minimizing the generation of by-products to the greatest extent. By-products may affect the performance of epoxy resins, and timely removal can avoid these adverse effects, thus ensuring the quality of the final product. The whole process is simple to operate, without the need to add additional cumbersome process technologies. Only by adding the corresponding catalyst and removing excess epichlorohydrin can high-quality epoxy resins be produced.

[0025] Meanwhile, the present application wants to emphasize that when preparing electronic-grade amine epoxy resins, the cost of raw materials used also needs to be considered. In the present application, p-aminophenol and epichlorohydrin are selected to synthesize intermediates because it is considered that the amino group of p-aminophenol itself will react with epichlorohydrin to form tertiary amine, which also has the effect of promoting ring-opening etherification, so that the amount of catalyst used can be greatly reduced. The inventors of the present application noticed that in the prior art, such as Chinese Patent Application No. CN201010154179.8, which discloses "a production method of low-residual tetrabromobisphenol A brominated epoxy resin", although it also adds a catalyst in the early etherification reaction and removes excess epichlorohydrin before the ring-closure reaction, since the raw materials used in this patent are the reaction of tetrabromobisphenol A and epichlorohydrin, and the structure of tetrabromobisphenol A itself does not directly have the effect of promoting ring-opening, then a catalyst needs to be completely used for catalysis, thus greatly increasing the amount of catalyst used, directly resulting in an increase in cost; and the greatly increased amount of catalyst used will also make the subsequent steps of removing excess catalyst more cumbersome and consume a large amount of resources. While increasing the cost, it will also make the catalyst easily remain in the whole reaction system, thus affecting the purity of the whole epoxy resin preparation.

[0026] Taking the above-mentioned comparative document as an example, there are also significant differences in the addition method and amount of alkali metal hydroxide in the closed-loop reaction in the comparative document. The liquid alkali in the comparative document is in excess relative to tetrabromobisphenol A, and there will be an overreaction. In the present application, the alkali metal hydroxide is added in two stages. In the first step, about 95% of the alkali metal hydroxide is added to close more than 90% of the epoxy groups. In the second stage, 10-15% of the alkali metal hydroxide is added to complete the closing of the remaining epoxy groups. In this embodiment, the alkali metal hydroxide is added in two times to avoid the self-polymerization of epoxy groups caused by high-concentration sodium hydroxide, thereby improving the product yield. When adding for the first time, the dehydrochlorination reaction can be initiated to gradually drive the reaction in the direction of ring closure. When adding for the second time, the reaction can be further promoted to ensure the complete progress of the ring-closing reaction. And the reaction conditions can be more precisely controlled to obtain an epoxy resin with a more uniform molecular weight distribution and a more stable epoxy value, which helps to improve the quality and consistency of the product. There will be no overreaction phenomenon in the whole reaction, ensuring that the reaction is within a controllable range and there is no waste of resources.

[0027] In a specific embodiment, the catalyst in the step S1 is one of benzyltriethylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium chloride, tetrabutylammonium hydrogensulfate, and dodecyltrimethylammonium chloride. Specifically, in this embodiment, an ammonium salt catalyst is used to accelerate the combination of epichlorohydrin and phenolic hydroxyl groups and promote the progress of the ring-opening reaction. Moreover, the ammonium salt catalyst will not introduce the generation of unnecessary products, ensuring the purity of the chlorohydrin ether intermediate.

[0028] In a specific embodiment, the mass ratio of the catalyst to p-aminophenol is (0.005% - 0.15%):1. At the same time, when carrying out the ring-opening reaction, the addition of p-aminophenol is as follows: p-aminophenol is divided into several portions, and each portion of p-aminophenol is added to epichlorohydrin in sequence for reaction.

[0029] It should be noted here that since a large amount of heat is released during the ring-opening reaction, in this embodiment, p-aminophenol is added in batches to control the reaction rate, thereby effectively managing the heat released during the reaction, helping to prevent local overheating, and avoiding side reactions or product degradation that may be caused by high temperature. At the same time, to a certain extent, it ensures the safety of the reaction and ensures that the reaction proceeds under safe conditions. More importantly, adding p-aminophenol in batches can better control the reaction conditions and avoid unnecessary side reactions. More stable reaction conditions mean fewer interruptions and accidents, thereby improving the continuous production capacity and achieving an increase in production efficiency.

[0030] Meanwhile, by controlling the mass ratio of the catalyst to p-aminophenol, the amounts of the catalyst and p-aminophenol are made to match, thereby ensuring an appropriate number of catalytically active sites in the reaction system, which helps to accelerate the ring-opening reaction of the phenolic hydroxyl group, shorten the reaction time, and improve production efficiency. If the amount of the catalyst is too large, it may lead to an excessively fast reaction rate and even trigger side reactions. If the amount of the catalyst is too small, the purpose of full reaction cannot be achieved. Therefore, the amount of the catalyst is correlated with the amount of p-aminophenol to ensure the reaction effect while reducing costs and enabling full reaction of all substances.

[0031] In a specific embodiment, the removal of epichlorohydrin in step S2 is specifically as follows: The recovery of epichlorohydrin is carried out under the conditions of a temperature of 60°C to 80°C, a pressure below 1 KPa, and a time of 2 to 4 h. By reasonably controlling the reaction conditions, epichlorohydrin can be fully removed without affecting the stability and purity of the intermediate chlorohydrin ether intermediate.

[0032] In a specific embodiment, the organic solvent is toluene or MIBK or isopropanol, and the amount of the organic solvent is 3 to 7 times the amount of p-aminophenol. By correlating the amount of the organic solvent with the amount of p-aminophenol, the concentrations of all components in the reaction system can be ensured to be in the optimal state, thereby optimizing the reaction efficiency. And to a certain extent, the usage amount of the organic solvent is reduced, saving costs while ensuring a stable and efficient reaction process.

[0033] In a specific embodiment, the concentration of the alkali metal hydroxide in step S3 is 20% to 50%; and the alkali metal hydroxide is a liquid alkali metal hydroxide or a solid alkali metal hydroxide.

[0034] In a specific embodiment, step S4 includes two washings to remove the excessive alkali metal hydroxide and the chlorides generated by the reaction; specifically, it includes the following steps: S41: First, wash with deionized water to remove the excessive alkali metal hydroxide and the chlorides generated by the reaction, and after liquid separation, carry out a refining reaction by adding the alkali metal hydroxide again to further reduce the chlorine content; S42: Second, add deionized water to wash the excessive alkali metal hydroxide and the chlorides generated by the reaction, and then adjust the pH of the system after the closed-loop reaction to neutral, and remove the organic solvent to obtain an electronic-grade amine epoxy resin.

[0035] In this embodiment, after undergoing a closed-loop reaction, it is washed multiple times to remove excessive alkali metal hydroxide and the chloride produced by the reaction, effectively removing impurities and improving the purity and performance of the epoxy resin. At the same time, after the first washing, by adding alkali metal hydroxide again for a refining reaction, the chlorine content can be further reduced to ensure that the purity of the product meets the requirements of electronic grade. Through washing and refining reactions, factors that are unfavorable to the stability of the epoxy resin can be removed, thereby improving the stability of the epoxy resin.

[0036] An electronic-grade amine epoxy resin is prepared by using the preparation method of an electronic-grade amine epoxy resin described in any one of the above. The electronic-grade amine epoxy resin prepared in the above manner has high purity, stable performance, and significantly reduced hydrolyzable chlorine and total chlorine contents, finally meeting the requirements of electronic-grade epoxy.

[0037] To further illustrate the effects of this application, the following examples are given: Example 1 A preparation method of an electronic-grade amine epoxy resin, which comprises the following steps: In a four-necked flask equipped with a stirrer, a temperature probe, and a condenser, add 300 parts of epichlorohydrin and 0.08 part of benzyltriethylammonium chloride. Pass nitrogen and heat to 45°C. Add 90 parts of p-aminophenol in three portions over 2 hours, control the reaction temperature at 50°C, and keep the temperature at 50°C for 4 hours after the addition is completed. After the reaction is completed, the unreacted epichlorohydrin in the four-necked flask is recovered under the conditions of a temperature of 70°C and a pressure below 1 KPa for 2 hours. After completely removing the epichlorohydrin, an intermediate product is obtained. Add 400 parts of methyl isobutyl ketone to dissolve the intermediate product, and slowly add 200 parts of a 50 wt.% NaOH aqueous solution dropwise over 4 hours. After the dropwise addition is completed, keep the temperature at 50°C and react for 2 hours. Add 400 parts of pure water to wash away the generated salt. Add 20 parts of a 30 wt.% NaOH aqueous solution and 5 parts of polyethylene glycol, and react at 60°C for 2 hours for a refining reaction. After the reaction is completed, add 100 parts of pure water, add 2 wt.% of sodium hydrogen phosphate to neutralize to pH 5.5 - 6.5 and separate the liquid. After multiple water washings, under the conditions of a temperature of 170°C and a pressure below 3 KPa, remove methyl isobutyl ketone to obtain the target product.

[0038] Test the epoxy equivalent, hydrolyzable chlorine, and total chlorine of the target product: epoxy equivalent = 108 g / eq, hydrolyzable chlorine = 75 ppm, total chlorine = 996 ppm.

[0039] Example 2 A preparation method of an electronic-grade amine epoxy resin, which comprises the following steps: In a four-necked flask equipped with a stirrer, a temperature probe and a condenser, add 300 parts of epichlorohydrin and 0.1 part of tetrabutylammonium bromide. Pass nitrogen and heat to 45°C. Add 90 parts of p-aminophenol in three portions over 2 hours, controlling the reaction temperature at 50°C. After the addition is complete, keep the temperature at 50°C for 4 hours. After the reaction is completed, recover the unreacted epichlorohydrin in the four-necked flask under the conditions of a temperature of 70°C and a pressure of 1 kPa or less for 2 hours. After completely removing the epichlorohydrin, an intermediate product is obtained. Then add 400 parts of methyl isobutyl ketone to dissolve it, and slowly add 200 parts of 50 wt.% NaOH aqueous solution dropwise over 4 hours. After the addition is complete, keep the temperature at 50°C and react for 2 hours. Add 400 parts of pure water to wash away the generated salt. Add 20 parts of 30 wt.% NaOH aqueous solution and 5 parts of polyethylene glycol, and react at 60°C for 2 hours for a refining reaction. After the reaction is completed, add 100 parts of pure water, add 2 wt.% sodium hydrogen phosphate to neutralize to pH 5.5 - 6.5, separate the layers, and after multiple water washes, remove methyl isobutyl ketone under the conditions of a temperature of 170°C and a pressure of 3 kPa or less to obtain the target product.

[0040] Test the epoxy equivalent, hydrolyzable chlorine and total chlorine of the target product: epoxy equivalent = 107 g / eq, hydrolyzable chlorine = 66 ppm, total chlorine = 975 ppm.

[0041] Example 3 A method for preparing an electronic-grade amine-based epoxy resin, which comprises the following steps: In a four-necked flask equipped with a stirrer, a temperature probe and a condenser, add 300 parts of epichlorohydrin and 0.12 part of tetrabutylammonium hydrogensulfate. Pass nitrogen and heat to 45°C. Add 90 parts of p-aminophenol in three portions over 2 hours, controlling the reaction temperature at 50°C. After the addition is complete, keep the temperature at 50°C for 4 hours. After the reaction is completed, recover the unreacted epichlorohydrin in the four-necked flask under the conditions of a temperature of 70°C and a pressure of 1 kPa or less for 2 hours. After completely removing the epichlorohydrin, an intermediate product is obtained. Then add 400 parts of methyl isobutyl ketone to dissolve it, and slowly add 200 parts of 50 wt.% NaOH aqueous solution dropwise over 4 hours. After the addition is complete, keep the temperature at 50°C and react for 2 hours. Add 400 parts of pure water to wash away the generated salt. Add 20 parts of 30 wt.% NaOH aqueous solution and 5 parts of polyethylene glycol, and react at 60°C for 2 hours for a refining reaction. After the reaction is completed, add 100 parts of pure water, add 2 wt.% sodium hydrogen phosphate to neutralize to pH 5.5 - 6.5, separate the layers, and after multiple water washes, remove methyl isobutyl ketone under the conditions of a temperature of 170°C and a pressure of 3 kPa or less to obtain the target product.

[0042] Test the epoxy equivalent, hydrolyzable chlorine and total chlorine of the target product: epoxy equivalent = 106 g / eq, hydrolyzable chlorine = 58 ppm, total chlorine = 945 ppm.

[0043] Example 4 A preparation method of an electronic-grade amine-based epoxy resin, which comprises the following steps: In a four-necked flask equipped with a stirrer, a temperature probe and a condenser, add 300 parts of epichlorohydrin and 0.09 part of dodecyltrimethylammonium chloride. Pass nitrogen and heat to 45°C. Add 90 parts of p-aminophenol in three portions over 2 hours, control the reaction temperature at 50°C, and keep the temperature at 50°C for 4 hours after the addition is complete; after the reaction is completed, recover the unreacted epichlorohydrin in the four-necked flask under the conditions of a temperature of 70°C and a pressure of 1 Kpa or less for 2 hours. After completely removing the epichlorohydrin, an intermediate product is obtained; then add 400 parts of methyl isobutyl ketone to dissolve it, and slowly add 200 parts of a 50 wt.% NaOH aqueous solution dropwise over 4 hours. After the addition is complete, keep the temperature at 50°C and react for 2 hours; add 400 parts of pure water to wash away the generated salt; add 20 parts of a 30 wt.% NaOH aqueous solution and 5 parts of polyethylene glycol, and react at 60°C for 2 hours for a refining reaction; after the reaction is completed, add 100 parts of pure water, add 2 wt.% of sodium hydrogen phosphate to neutralize to pH 5.5 - 6.5, separate the liquid, and after washing with water multiple times, remove methyl isobutyl ketone under the conditions of a temperature of 170°C and a pressure of 3 Kpa or less to obtain the target product.

[0044] Test the epoxy equivalent, hydrolyzable chlorine and total chlorine of the target product: epoxy equivalent = 108 g / eq, hydrolyzable chlorine = 80 ppm, total chlorine = 991 ppm.

[0045] Comparative Example 1 The difference from Example 1 is that no catalyst is added during the ring-opening reaction stage of epichlorohydrin and p-aminophenol, and the target product is obtained under the same remaining conditions.

[0046] Test the epoxy equivalent, hydrolyzable chlorine and total chlorine of the target product: epoxy equivalent = 125 g / eq, hydrolyzable chlorine = 235 ppm, total chlorine = 3548 ppm.

[0047] Comparative Example 2 The difference from Example 1 is that the excess epichlorohydrin in the system is not removed before the ring-closing reaction stage, and the target is obtained under the same remaining conditions.

[0048] Test the epoxy equivalent, hydrolyzable chlorine and total chlorine of the target product: epoxy equivalent = 116 g / eq, hydrolyzable chlorine = 195 ppm, total chlorine = 2349 ppm.

[0049] Comparative Example 3 Different from Example 1, tetrabutylammonium bromide was changed to benzyltriphenylammonium bromide with an addition amount of 1.0 part. The reaction temperature was 94 °C, and the etherification was carried out for 3.5 hours. After the reaction, epichlorohydrin was removed; then 400 parts of toluene was added for dissolution, and 300 parts of 50 wt.% NaOH aqueous solution was added dropwise in three portions, and the temperature was maintained at 70 °C for 6 hours.

[0050] The epoxy equivalent, hydrolyzable chlorine and total chlorine of the target product were tested: epoxy equivalent = 155 g / eq, hydrolyzable chlorine = 572 ppm, total chlorine = 5254 ppm.

[0051] From the test results of the above examples and comparative examples, the total chlorine content of the electronic-grade amine epoxy resin prepared by the preparation method of the present application is much lower than that of the epoxy resin prepared by the prior art. The difference is in the hundreds and thousands order of magnitude. Chlorine is a reactive element and easily causes adverse reactions such as degradation and discoloration in the resin, thereby affecting the insulation performance, heat resistance and mechanical properties of the resin, etc.; the significant reduction of the total chlorine content can significantly improve the stability and reliability of the epoxy resin, making it more suitable for high-tech fields such as electronic components, optical fiber communication, and aerospace.

[0052] The examples described in the present invention are only descriptions of the preferred embodiments of the present invention, and do not limit the concept and scope of the present invention. Without departing from the design idea of the present invention, various deformations and improvements made by those skilled in the art to the technical solutions of the present invention should fall within the protection scope of the present invention.

Claims

1. A preparation method of an electronic-grade amine-based epoxy resin, characterized in that: It includes the following steps: S1: Ring-opening reaction: p-aminophenol reacts with epichlorohydrin to synthesize a chlorohydrin ether intermediate; meanwhile, a catalyst for promoting the reaction of epichlorohydrin is added during the ring-opening reaction stage; the mass ratio of the catalyst to p-aminophenol is (0.005% - 0.15%):1; S2: After the ring-opening reaction is completed, epichlorohydrin is removed; S3: Ring-closing reaction: A dehydrochlorination reaction is carried out by adding an organic solvent and an alkali metal hydroxide to the system after the ring-opening reaction is completed, and the target product is formed by ring-closing; wherein, the addition of the alkali metal hydroxide is divided into two times: The first time, an aqueous sodium hydroxide solution with a dosage 2 - 2.5 times that of p-aminophenol is added dropwise, the reaction time is 2 - 6 hours, and the reaction temperature is controlled at 40 - 60°C; the second time, an aqueous sodium hydroxide solution with a dosage 0.2 - 0.25 times that of p-aminophenol is added; the reaction is carried out for 2 - 4 hours, and the reaction temperature is controlled at 50 - 80°C; S4: Wash to remove the excessive alkali metal hydroxide and the chlorides generated by the reaction, and finally obtain an electronic-grade amine epoxy resin.

2. The preparation method of an electronic-grade amine-based epoxy resin according to claim 1, characterized in that: The catalyst in the step S1 is one of benzyltriethylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium chloride, tetrabutylammonium hydrogensulfate, and dodecyltrimethylammonium chloride.

3. The preparation method of an electronic-grade amine-based epoxy resin according to claim 2, characterized in that: When carrying out the ring-opening reaction, the addition of p-aminophenol is as follows: p-aminophenol is divided into several portions, and each portion of p-aminophenol is added to epichlorohydrin in sequence for reaction.

4. The preparation method of an electronic-grade amine-based epoxy resin according to claim 1, wherein: The removal of epichlorohydrin in the step S2 is specifically: The removal and recovery of epichlorohydrin are carried out under the conditions of a temperature of 60°C - 80°C, a pressure of less than 1 Kpa, and a time of 2 - 4 h.

5. The preparation method of an electronic-grade amine-based epoxy resin according to claim 1, wherein: The organic solvent is toluene or MIBK or isopropanol, and the amount of the organic solvent is 3 - 7 times the amount of p-aminophenol.

6. The preparation method of an electronic-grade amine-based epoxy resin according to claim 1, wherein: The concentration of the alkali metal hydroxide in the step S3 is 20% - 50%; and the alkali metal hydroxide is a liquid alkali metal hydroxide or a solid alkali metal hydroxide.

7. The preparation method of an electronic-grade amine-based epoxy resin according to claim 1, characterized in that: The step S4 includes two washes to remove the excessive alkali metal hydroxide and the chlorides generated by the reaction; specifically, it includes the following steps: S41: The first wash removes the excessive alkali metal hydroxide and the chlorides generated by the reaction, and after liquid separation, a refining reaction is carried out by adding an alkali metal hydroxide again to further reduce the chlorine content; S42: The second time, water is added to wash the excessive alkali metal hydroxide and the chlorides generated by the reaction, and then the pH of the system after the ring-closing reaction is adjusted to neutral, and the solvent is removed to obtain an electronic-grade amine epoxy resin.

8. An electronic-grade amine-based epoxy resin, characterized in that: It is prepared by using the preparation method of an electronic-grade amine epoxy resin according to any one of claims 1 - 7.

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