A trisglycidyl 4-amino-3-methylphenol epoxy resin, its preparation method and use

Abstract

This application belongs to the field of epoxy resin technology, and specifically relates to a triglycidyl-4-amino-3-methylphenol epoxy resin, its preparation method, and its applications. The triglycidyl-4-amino-3-methylphenol epoxy resin is prepared by first subjecting 4-amino-3-methylphenol monomer and epichlorohydrin to an etherification grafting reaction under a catalyst, then reacting the resulting 4-amino-3-methylphenol chlorohydrin ether with NaOH to undergo a ring-closure reaction, followed by purification and refining steps. The obtained triglycidyl-4-amino-3-methylphenol epoxy resin monomer purity can reach up to 92.1%, and it can be stored for 11-15 months at 15-30°C and 40-85% RH humidity. Due to its high purity, long shelf life, high temperature resistance, and low water absorption, adhesives prepared using this resin can be widely used for bonding and sealing electronic equipment and automotive products where environmental temperature changes are critical.

Description

Technical Field

[0001] This application belongs to the field of high temperature resistant and low water absorption epoxy resin technology, and specifically relates to a triglycidyl-4-amino-3-methylphenol epoxy resin, its preparation method and application. Background Technology

[0002] Triglycidyl-based epoxy resins include p-aminophenol epoxy resins and m-aminophenol epoxy resins, etc. The structural formula of existing triglycidyl-based aminophenol epoxy resins, such as triglycidyl-based m-aminophenol epoxy resin, is as follows:

[0003] .

[0004] After curing with methylmethylenetetrahydrophthalic anhydride, its Tg value reached 241℃ and its impact strength was 16-20 KJ / m. 2 Flexural strength 180-190 MPa, tensile strength 50-70 MPa.

[0005] Triglycidylaminophenol epoxy resin, due to its advantages such as low viscosity, excellent wettability, high Tg value, high strength, and impact resistance after curing, can be widely used in electronic adhesives and aerospace composite materials. Its synthesis involves the reaction of corresponding aminophenol precursors (such as p-aminophenol, m-aminophenol, and o-aminophenol) with epichlorohydrin through etherification, grafting addition, and ring-closure reactions. Because the amino group in the aminophenol precursor has two active hydrogens, it needs to undergo ring-opening etherification with two molecules of epichlorohydrin. In existing processes, the amino reaction is incomplete, and the presence of a small amount of active amino hydrogens negatively impacts the long-term stability of the finished product. During storage, the residual small amount of active amino hydrogens acts as a catalyst, causing ring-opening of the epoxy group, thus increasing the viscosity of the product during storage and even causing gelation, leading to product failure. Existing products in this series, such as grade AFG-90 / MF-3101L, are specifically labeled with a shelf life of only six months. Therefore, there is an urgent need to improve the process of such products, increase the conversion efficiency of amino active hydrogen, synthesize finished products with high monomer content, improve the stability over time, and extend the product shelf life. This is of great significance for the application of such products.

[0006] In summary, the current preparation process of triglycidylaminophenol epoxy resin has technical problems such as low amino conversion efficiency, resulting in low purity of the final product, poor stability over time, and short product storage time. Summary of the Invention

[0007] The purpose of this invention is to solve the technical problems of low conversion efficiency of amino active hydrogen in the preparation process of triglycidyl aminophenol epoxy resin, which leads to low monomer purity, poor stability over time, and short storage time of the final product. This invention provides a triglycidyl 4-amino-3-methylphenol epoxy resin, its preparation method, and its application, which features high conversion rate of amino active hydrogen during product preparation, high monomer purity, good stability over time, long storage time, good high-temperature stability, and low water absorption after curing.

[0008] The technical principle of this application is that the presence of a methyl electron-donating group in the molecular structure of 4-amino-3-methylphenol greatly reduces the reactivity of the monomer molecule. In addition, the substitution of the ortho position of the amino group with a methyl group further reduces the reactivity of 4-amino-3-methylphenol. Furthermore, the active hydrogen of the amino group is not completely reacted during the etherification grafting reaction, resulting in lower purity of the finished monomer. However, by combining the use of a special catalyst in the preparation process with the synergistic effect of controlling the pressure and temperature during the reaction, a triglycidyl 4-amino-3-methylphenol epoxy resin with high monomer purity, longer storage time, and better hydrophobic properties can be synthesized.

[0009] The technical solution of this application

[0010] In a first aspect, this application provides a triglycidyl-4-amino-3-methylphenol epoxy resin, which adopts the following technical solution: a triglycidyl-4-amino-3-methylphenol epoxy resin, with the following chemical structural formula:

[0011] .

[0012] The triglycidyl-4-amino-3-methylphenol epoxy resin described above contains a methyl group, which gives it superior physicochemical advantages over p-aminophenol or m-aminophenol epoxy resins. In addition to these advantages, it also boasts higher purity, better storage stability, and improved hydrophobic properties (lower water absorption). For example, its epoxy equivalent distribution is 105–116 g / eq (compared to 100–111 g / eq for p-aminophenol or m-aminophenol epoxy resins), and its readily saponifiable chlorine content is 47–98 ppm (compared to 50–200 ppm for p-aminophenol or m-aminophenol epoxy resins). After curing, its Tg value is 245–250℃, and its impact strength is 25–46 KJ / m². 2 It has a flexural strength of 178–198 MPa, a tensile strength of 70–80 MPa, and a water absorption rate of ≤0.1%.

[0013] Secondly, this application provides a method for preparing the above-mentioned triglycidyl 4-amino-3-methylphenol epoxy resin, and the reaction equation for the preparation process is shown below (where NaOH + quaternary ammonium salt represents the catalyst):

[0014]

[0015] First, 4-amino-3-methylphenol monomer and epichlorohydrin undergo an etherification grafting reaction under the action of a catalyst to obtain product A, namely 4-amino-3-methylphenol chlorohydrin ether. The obtained 4-amino-3-methylphenol chlorohydrin ether then undergoes a ring-closing reaction with NaOH to obtain triglycidyl 4-amino-3-methylphenol epoxy resin.

[0016] NaOH can be replaced with KOH.

[0017] The following technical solution is adopted:

[0018] A method for preparing triglycidyl-4-amino-3-methylphenol epoxy resin involves firstly, 4-amino-3-methylphenol monomer undergoes an etherification grafting reaction with epichlorohydrin under the action of a catalyst. The resulting 4-amino-3-methylphenol chlorohydrin ether (product A) undergoes a ring-closure reaction with sodium hydroxide under a negative pressure of 0.07–0.09 MPa and a temperature of 30–50 °C to obtain 4-amino-3-methylphenol epoxy resin and sodium chloride. To further reduce the easily saponifiable chlorine in the resin, a further purification reaction with sodium hydroxide is performed after the ring-closure reaction. After purification and other steps, a high-purity triglycidyl-4-amino-3-methylphenol epoxy resin with good storage stability is finally obtained.

[0019] The specific preparation steps of the above-mentioned triglycidyl 4-amino-3-methylphenol epoxy resin are as follows:

[0020] (1) Etherification grafting reaction

[0021] In a container, 4-amino-3-methylphenol monomer, epichlorohydrin, catalyst and solvent I are added sequentially. The three active groups in the 4-amino-3-methylphenol monomer (two active hydrogens of the amino group and one active hydrogen of the hydroxyl group) react with epichlorohydrin in solvent I at a controlled temperature of 30-70°C for 3-8 hours to obtain a reaction solution containing 4-amino-3-methylphenol chlorohydrin ether.

[0022] The preferred temperature for the etherification grafting reaction process described above is 30–55°C. This is primarily to reduce side reactions caused by high temperatures, which would ultimately lead to a decrease in the purity and an increase in the epoxy equivalent of the triglycidyl 4-amino-3-methylphenol epoxy resin product. Specific side reactions are shown in the following reaction equation (where NaOH + quaternary ammonium salt represents the catalyst):

[0023]

[0024] Epichlorohydrin hydrolyzes in an alkaline environment, and the resulting glycidol further reacts with 4-amino-3-methylphenol monomer to produce byproduct B in the above reaction equation. R1, R2, and R3 in the structural formula can be -OH or -Cl, but R1, R2, and R3 cannot all be -Cl at the same time. This is because if they are all -Cl, it will be product A of the etherification grafting reaction, namely 4-amino-3-methylphenol chlorohydrin ether. The byproduct can also further undergo a ring-closing reaction with NaOH, which will reduce the monomer purity of the final product, triglycidyl 4-amino-3-methylphenol epoxy resin, and affect its quality.

[0025] The catalyst is at least one of alkali metal solution, alkaline earth metal salt, quaternary ammonium salt, ethyl triphenylphosphine, and triphenylphosphine.

[0026] The alkali metal solution is an aqueous solution of sodium hydroxide, which can be replaced by an aqueous solution of potassium hydroxide.

[0027] The alkaline earth metal salts mentioned are calcium chloride, magnesium sulfate, or barium sulfate;

[0028] The quaternary ammonium salt is methyltrioctylammonium chloride, decyldimethylammonium chloride, bisoctyldimethylammonium chloride, dimethylbisoctadecylammonium chloride, benzyldimethyloctylammonium chloride, dodecyltrimethylammonium chloride, octadecyltrimethylammonium chloride, tetraethylammonium bromide, benzyltriethylammonium chloride, benzyldiethylammonium bromide or benzyltrimethylammonium bromide;

[0029] Preferably, the catalyst is composed of a quaternary ammonium salt and an alkali metal solution: the quaternary ammonium salt is dodecyltrimethylammonium chloride, and the alkali metal solution is a sodium hydroxide aqueous solution with a mass percentage concentration of 40-50%. The mass ratio of dodecyltrimethylammonium chloride to sodium hydroxide aqueous solution is 1:28-30.

[0030] Preferably, the amount of sodium hydroxide aqueous solution with a mass percentage concentration of 40-50% in the composite catalyst is such that the molar ratio of 4-amino-3-methylphenol to sodium hydroxide aqueous solution with a mass percentage concentration of 40-50% is 1:0.53.

[0031] The catalysts in this application are only exemplified by the composite catalyst obtained by combining sodium hydroxide aqueous solution in alkali metal solution and dodecyltrimethylammonium chloride in quaternary ammonium salt, but do not limit the use of other catalysts listed above, either alone or in combination.

[0032] The preferred etherification grafting reaction process described above uses two composite catalysts, which effectively overcomes the negative effect of the methyl group in the 4-amino-3-methylphenol monomer on the reduced reactivity. This significantly improves the reaction efficiency of the three active groups (two active hydrogens of the amino group and one active hydrogen of the hydroxyl group) in the 4-amino-3-methylphenol monomer with epichlorohydrin, thereby increasing the yield of the 4-amino-3-methylphenol epoxy resin product, which can reach up to 98.7%.

[0033] Preferably, the sodium hydroxide aqueous solution in the catalyst is added in 2 to 5 batches, with one batch added after each 30-minute reaction; more preferably, it is added in 4 batches. The reason for this is that adding it every 30 minutes prevents the temperature of the reaction system from fluctuating too much due to changes in the amount of feed, thus ensuring that the etherification grafting reaction proceeds stably and effectively.

[0034] The above-mentioned amounts of 4-amino-3-methylphenol: epichlorohydrin: catalyst, calculated by molar ratio, are 1:6~15:0.1~0.6.

[0035] In the aforementioned etherification grafting reaction stage, the amount of epichlorohydrin has little effect on the reaction efficiency of the grafting reaction in the etherification stage, and also has little effect on the purity of the final product, triglycidyl-4-amino-3-methylphenol epoxy resin. However, in a reactor of the same volume, if the molar number of epichlorohydrin increases while the total amount of feed remains unchanged, the amount of 4-amino-3-methylphenol fed will inevitably decrease, resulting in a lower yield of triglycidyl-4-amino-3-methylphenol epoxy resin. Therefore, in order to improve the maximum utilization rate of the reactor, this application prefers the ratio of 4-amino-3-methylphenol to epichlorohydrin, calculated by molar ratio, which is 1:6 to 10.

[0036] Solvent I is an alcohol ether co-solvent, which is at least one of ethanol, butanol, ethylene glycol, propylene glycol, isopropanol, ethylene glycol monomethyl ether, propylene glycol monomethyl ether, and tripropylene glycol monomethyl ether. This application uses isopropanol as an example only, but does not limit the use of other solvents among the above-mentioned alcohol ether co-solvents.

[0037] The amount of solvent I used is calculated based on the mass ratio of solvent I to epichlorohydrin, where solvent I to epichlorohydrin is 10 to 30: 100.

[0038] The etherification grafting reaction time is 3-8 hours. The reaction efficiency of the etherification grafting reaction of 4-amino-3-methylphenol monomer can reach up to 98.9%. The higher the reaction efficiency of the etherification grafting reaction of 4-amino-3-methylphenol monomer, the higher the conversion efficiency of amino active hydrogen. This shows that the preparation method of triglycidyl 4-amino-3-methylphenol epoxy resin of this application has a high conversion efficiency of amino active hydrogen.

[0039] Taking into account production efficiency, the reaction efficiency of the etherification grafting reaction of 4-amino-3-methylphenol monomer is preferably 86.0-98.5% within 3-6 hours.

[0040] More preferably, the conversion efficiency of 4-amino-3-methylphenol monomer can reach 95.0-98.5% when the reaction time is 4-6 hours.

[0041] (2) Closed-loop reaction

[0042] Under controlled negative pressure of 0.07-0.09 MPa and temperature of 30-50°C, sodium hydroxide aqueous solution was added to the reaction solution containing 4-amino-3-methylphenol chlorohydrin ether obtained in step (1), and then the negative pressure was maintained at 0.07-0.09 MPa and temperature at 30-50°C for 2-3 hours to carry out the ring-closure reaction, thereby obtaining reaction solution I containing triglycidyl 4-amino-3-methylphenol epoxy resin; the reaction solution I contains not only triglycidyl 4-amino-3-methylphenol epoxy resin, but also sodium chloride, unreacted epichlorohydrin, solvent I and byproducts;

[0043] The sodium hydroxide aqueous solution has a mass percentage concentration of 40-50%.

[0044] The amount of sodium hydroxide in the above-mentioned sodium hydroxide aqueous solution, calculated by molar ratio, is 1:2.0~2.7 for the sodium hydroxide aqueous solution used in the 4-amino-3-methylphenol ring-closing reaction in step (1).

[0045] The addition rate of the sodium hydroxide aqueous solution mentioned above is controlled at 1.25 to 2.25 g / min, that is, the mass of sodium hydroxide aqueous solution added per minute is 1.25 to 2.25 g;

[0046] If the catalyst in step (1) contains an aqueous solution of potassium hydroxide, the aqueous solution of sodium hydroxide used in the ring-closing reaction shall be replaced with an aqueous solution of potassium hydroxide.

[0047] In the above closed-loop reaction, controlling the amount and rate of sodium hydroxide aqueous solution addition is to ensure that the saponifiable chlorine content is controlled within a reasonable range after the closed-loop reaction. Combined with the following step (4) refining reaction process, controlling the appropriate temperature and time of the refining reaction is necessary to finally obtain a triglycidyl 4-amino-3-methylphenol epoxy resin product with higher monomer purity and lower epoxy equivalent. The reason for this may be that if the sodium hydroxide aqueous solution is added too quickly during the closed-loop reaction, the reaction will be violent, the side reactions will increase, and the purity of the final resin product will be affected. If the addition rate is too slow, the production efficiency will be affected. In addition, if too much sodium hydroxide aqueous solution is added during the closed-loop reaction, the saponifiable chlorine content will be too low. After the refining reaction is completed, this will lead to an increase in the amount of waste and difficulties in treatment. If too little sodium hydroxide aqueous solution is added, the saponifiable chlorine content will be too high, which will lead to the excessive use of sodium hydroxide aqueous solution in the refining reaction and increase costs.

[0048] The above-mentioned ring-closure reaction is carried out under negative pressure, mainly to improve the utilization efficiency of sodium hydroxide aqueous solution in the ring-closure reaction, reduce the waste of raw material epichlorohydrin caused by hydrolysis, and affect the quality of the final product triglycidyl 4-amino-3-methylphenol epoxy resin.

[0049] Preferably, when the reaction temperature of the closed-loop reaction is 30-45°C, especially when the temperature is 40°C, the final obtained triglycidyl 4-amino-3-methylphenol epoxy resin has higher purity, reaching 92.1%, when the same purification reaction conditions and the same purification conditions are used in the subsequent preparation process.

[0050] 1. After the closed-loop reaction in step (2) is completed, adjust the pressure to a negative pressure of 0.098 MPa and raise the temperature to 80-125°C to remove solvent I and excess unreacted epichlorohydrin. When the amount of unreacted epichlorohydrin and solvent I is below 500 ppm, add solvent II and mix evenly to obtain reaction solution II containing triglycidyl 4-amino-3-methylphenol epoxy resin. In addition to triglycidyl 4-amino-3-methylphenol epoxy resin, reaction solution II also contains solvent II, sodium chloride, byproducts, less than 500 ppm of epichlorohydrin and solvent I.

[0051] The removal status of the unreacted epichlorohydrin and solvent I can be determined by gas chromatography, which detects the residual amounts of epichlorohydrin and solvent I in the reaction solution after the removal process.

[0052] Solvent II is at least one of toluene, xylene, methyl ethyl ketone, and methyl isobutyl ketone; solvent II in this application is only exemplified by toluene, but the use of other solvents in solvent II is not limited;

[0053] The amount of solvent II added is calculated based on its mass ratio to the theoretically obtainable triglycidyl 4-amino-3-methylphenol epoxy resin, that is, the amount of solvent II added is 1 to 2.75 times the mass of the theoretically obtained triglycidyl 4-amino-3-methylphenol epoxy resin.

[0054] The amount of triglycidyl 4-amino-3-methylphenol epoxy resin that should theoretically be obtained is calculated based on the reaction efficiency of the etherification grafting reaction of 4-amino-3-methylphenol used in step (1) being 100%, and under the condition that the ring-closing reaction is complete, the amount of triglycidyl 4-amino-3-methylphenol epoxy resin obtained.

[0055] The embodiments of this application only use toluene as solvent II for illustrative purposes, but do not limit the use of xylene, butanone, or methyl isobutyl ketone;

[0056] (4) Refining reaction

[0057] Because the molar ratio of the sodium hydroxide aqueous solution added in steps (1) and (2) to 4-amino-3-methylphenol chlorohydrin ether is less than 3:1, a small amount of 4-amino-3-methylphenol chlorohydrin ether (the chlorine on this structure is called saponifiable chlorine) will remain and need to be further closed in order to further improve the purity of 4-amino-3-methylphenol epoxy resin.

[0058] Add a 40-50% sodium hydroxide aqueous solution to the reaction solution II containing triglycidyl 4-amino-3-methylphenol epoxy resin obtained in step (3) for purification reaction. The purification reaction process is controlled at a temperature of 60-100℃ and a time of 2-9h to obtain a purified reaction solution. The purified reaction solution contains, in addition to triglycidyl 4-amino-3-methylphenol epoxy resin, sodium chloride, solvent II (toluene) and sodium hydroxide aqueous solution, etc.

[0059] The amount of sodium hydroxide aqueous solution with a mass percentage concentration of 40-50% added is 2-4 times the number of moles of saponifiable chlorine in the theoretically obtainable triglycidyl-4-amino-3-methylphenol epoxy resin. The amount of triglycidyl-4-amino-3-methylphenol epoxy resin that should be obtained is calculated based on the reaction efficiency of the etherification grafting reaction of 4-amino-3-methylphenol used in step (1) being 100%, and under the condition that the ring-closing reaction is complete, the amount of triglycidyl-4-amino-3-methylphenol epoxy resin obtained is...

[0060] In the above-mentioned refining process, if the reaction temperature is too high, the reaction will proceed too quickly, resulting in some aged resin. It will also cause poor separation efficiency in the subsequent purification process, and the purity of the final product, triglycidyl-4-amino-3-methylphenol epoxy resin, will also decrease. On the other hand, if the reaction temperature is too low, the reaction will proceed too slowly, and under the same refining reaction time, the saponifiable chlorine content of the final product, triglycidyl-4-amino-3-methylphenol epoxy resin, will be too high.

[0061] During the refining process, excessively long reaction time will affect production efficiency; while excessively short reaction time will result in high levels of easily saponifiable chlorine residue, which will affect the quality of the final product, triglycidyl-4-amino-3-methylphenol epoxy resin.

[0062] Taking into account the content of easily saponifiable chlorine in the final triglycidyl 4-amino-3-methylphenol epoxy resin and the separation of the liquid during the purification process after the purification reaction, it is preferred to control the purification reaction temperature at 70-85℃ and the time at 2-5h. After purification under the same purification conditions, the final triglycidyl 4-amino-3-methylphenol epoxy resin with an easily saponifiable chlorine content of 47-98ppm will have better separation effect in subsequent purification steps.

[0063] (5) Purification

[0064] ① Add water to the purified reaction solution obtained in step (4) above, stir and mix well, and let stand to separate into layers to obtain the salt water phase and the organic phase composed of resin / solvent II. Remove the lower salt water phase to remove the by-product salt, that is, remove sodium chloride, and obtain the organic phase composed of resin / solvent II.

[0065] The amount of water added is 3 to 6 times the mass of sodium chloride, a byproduct salt theoretically produced by the etherification grafting reaction in step (1). To save water and energy, the amount of water added is preferably 3 to 4.5 times.

[0066] ② Add a pH adjuster to the organic phase composed of resin / solvent II obtained in ① to control the pH value of the organic phase composed of resin / solvent II to 5-7. Then let it stand and separate the liquid. After removing the lower aqueous phase, the organic phase composed of resin / solvent II with a pH value of 5-7 is obtained.

[0067] The pH adjuster is one of phosphoric acid, sodium hydrogen phosphate, hydrochloric acid, and oxalic acid.

[0068] ③ Add water to the organic phase composed of resin / solvent II with a pH value of 5-7 obtained in ② and wash it with water 1-3 times until there is no sodium chloride in the effluent, and you will get a crude product containing triglycidyl 4-amino-3-methylphenol epoxy resin and solvent II.

[0069] ④ The crude product containing triglycidyl 4-amino-3-methylphenol epoxy resin and solvent II obtained in ③ is evaporated at a controlled pressure of negative pressure of 0.0985-0.099 MPa and a temperature of 125-140℃ to remove solvent II, thereby obtaining triglycidyl 4-amino-3-methylphenol epoxy resin.

[0070] By employing the above-mentioned technical solution, a composite catalyst, particularly one containing an alkali metal solution, is used in the etherification grafting stage. Simultaneously, the amount and rate of sodium hydroxide aqueous solution added during the ring-closure reaction are controlled, along with the synergistic effect of controlling the ring-closure reaction within a reasonable pressure range and the temperature and time of the purification reaction. This effectively overcomes the effects of decreased activity of the 4-amino-3-methylphenol monomer due to the addition of methyl groups and incomplete reaction of the active hydrogen in the amino group. This significantly improves the reaction efficiency of the etherification grafting reaction between the active groups in the 4-amino-3-methylphenol monomer and epichlorohydrin, thereby increasing the final yield. The yield of triglycidyl-4-amino-3-methylphenol epoxy resin in the product can reach 98.7%, which also improves the purity of the final product. In particular, when using a catalyst composed of alkali metal solution and quaternary ammonium salt, especially a catalyst composed of NaOH aqueous solution and dodecyltrimethylammonium chloride, the purity of the obtained triglycidyl-4-amino-3-methylphenol epoxy resin can reach up to 92.1%, which meets the requirements for direct use in electronic equipment or aerospace materials, i.e., no further purification is required.

[0071] Furthermore, in the preparation process, due to the use of a composite catalyst and by controlling the etherification grafting reaction temperature to 30–55°C and the reaction time to 3–6 h, the reaction efficiency of the etherification grafting reaction is 86.0–98.5%. In particular, when the etherification grafting reaction time is 4–6 h, the reaction efficiency is 95.0–98.5%, and the product yield is also the highest, ranging from 98.1% to 98.7%.

[0072] Furthermore, the sodium hydroxide aqueous solution in the composite catalyst used in the etherification grafting reaction during the preparation process was added in batches, especially in 4 batches. This resulted in better reaction efficiency of the 4-amino-3-methylphenol monomer in the etherification grafting reaction, leading to a higher purity of the final product, reaching 92.1%. The reason for this is likely that adding the solution every 30 minutes resulted in smaller fluctuations in temperature within the system, which was more conducive to the stable progress of the etherification grafting reaction.

[0073] Furthermore, when the amount of sodium hydroxide aqueous solution used in the composite catalyst for the etherification grafting reaction in the preparation process is 1:0.53 (molar ratio of 4-amino-3-methylphenol to sodium hydroxide aqueous solution), the separation condition during the purification stage of the preparation process is good, and the product purity is higher, reaching 92.1%.

[0074] Furthermore, in the closed-loop reaction of the preparation process, by controlling the amount and rate of sodium hydroxide aqueous solution added, and simultaneously controlling the temperature of the purification reaction at 70-85℃ for 2-5 hours, it can be ensured that the saponifiable chlorine after the purification reaction is controlled at 47-98 ppm. After further processing, a triglycidyl-4-amino-3-methylphenol epoxy resin product with a purity of 90.0-92.1% and an epoxy equivalent of 105-116 g / eq is obtained.

[0075] Furthermore, the storage stability and high-temperature stability of the triglycidyl 4-amino-3-methylphenol epoxy resin finally obtained by the above preparation method are as follows:

[0076] Under conditions of 15–30°C and RH of 40–85%, the above-mentioned triglycidyl 4-amino-3-methylphenol epoxy resin did not change its GPC spectral distribution after being stored for 11–15 months, and the viscosity change rate at 25°C was less than 10%, which indicates that the triglycidyl 4-amino-3-methylphenol epoxy resin has good storage stability.

[0077] Meanwhile, the above-mentioned triglycidyl-4-amino-3-methylphenol epoxy resin was baked at 190°C for 3 hours, and its purity decreased by only 3% (from 92.1% to 89.1%), while the viscosity increased by 4%. Compared with commercially available triglycidyl-p-aminophenol epoxy resin, under the same conditions, its purity decreased by 16% (from 72% to 56%), and the viscosity increased by 34%. This shows that the triglycidyl-4-amino-3-methylphenol epoxy resin obtained by the preparation method of this application has good high-temperature stability and can withstand the influence of high environmental temperatures on product performance. Therefore, the triglycidyl-4-amino-3-methylphenol epoxy resin obtained by the preparation method of this application has relatively low requirements for storage environment temperature or temperature changes, which can further corroborate the technical effect of the triglycidyl-4-amino-3-methylphenol epoxy resin obtained by the preparation method of this application having a long shelf life.

[0078] Thirdly, this application provides an adhesive containing the above-mentioned triglycidyl 4-amino-3-methylphenol epoxy resin, the specific technical solution of which is as follows:

[0079] An adhesive containing triglycidyl 4-amino-3-methylphenol epoxy resin, wherein the raw materials used in its preparation, calculated by weight, are: triglycidyl 4-amino-3-methylphenol epoxy resin, curing agent, and accelerator, in the following proportions: 100 parts, 100-150 parts, and 0.1-0.6 parts, respectively.

[0080] The curing agent mentioned above is an acid anhydride curing agent, which is one or more of methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride and methylnadic anhydride.

[0081] The aforementioned accelerators are imidazole, benzyl dimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, or o-hydroxybenzyl dimethylamine; this application only uses methyltetrahydrophthalic anhydride as the curing agent and benzyl dimethylamine as the accelerator as an example, and does not limit the use of the above-mentioned other curing agents and other accelerators in adhesives containing triglycidyl 4-amino-3-methylphenol epoxy resin;

[0082] The raw materials used in the above-mentioned adhesive containing triglycidyl 4-amino-3-methylphenol epoxy resin are stored separately, mixed before use, and then cured.

[0083] The preparation method of the above-mentioned adhesive containing triglycidyl 4-amino-3-methylphenol epoxy resin includes the following specific steps:

[0084] First, add the above-mentioned triglycidyl 4-amino-3-methylphenol epoxy resin, curing agent and accelerator into a container in sequence, and stir and mix evenly while controlling the temperature at 20±2℃ to obtain an adhesive containing triglycidyl 4-amino-3-methylphenol epoxy resin.

[0085] The Tg, impact strength, flexural strength, tensile strength, and hydrophobic properties of the adhesive containing triglycidyl 4-amino-3-methylphenol epoxy resin obtained above after curing are as follows:

[0086] The curing process involves sequentially curing the adhesive containing triglycidyl 4-amino-3-methylphenol epoxy resin at 120°C for 2 hours and then at 160°C for 2 hours.

[0087] The Tg value after curing is 245-250℃, which indicates that it has excellent high temperature resistance.

[0088] The impact strength after curing is 25–46 KJ / m. 2 With a flexural strength of 178–198 MPa and a tensile strength of 70–80 MPa, it is evident that it has excellent resistance to deformation.

[0089] The water absorption rate after curing is ≤0.1%, which indicates that it has excellent hydrophobic properties;

[0090] In summary, the adhesive containing triglycidyl 4-amino-3-methylphenol epoxy resin of this application, after being cured using methyltetrahydrophthalic anhydride as a curing agent, not only has excellent Tg and deformation resistance, but also better hydrophobic properties, and can be widely used in electronic equipment and automotive products.

[0091] Beneficial technical effects of this application

[0092] Compared with existing technologies, the beneficial technical effects of the technical solution in this application are as follows:

[0093] This application discloses a method for preparing triglycidyl 4-amino-3-methylphenol epoxy resin. In the etherification grafting stage, two composite catalysts are preferred, especially the combination of alkali metal solution and quaternary ammonium salt, and even more particularly the combination of sodium hydroxide aqueous solution and dodecyltrimethylammonium chloride. Especially when the alkali metal solution is added in batches, and under the synergistic effect of controlling the appropriate amount and rate of sodium hydroxide aqueous solution addition and the temperature of the purification reaction process in combination with the closed-loop reaction, the reaction efficiency of the etherification grafting reaction of 4-amino-3-methylphenol monomer can reach more than 95.0%, and can reach up to 98.9%, and the yield of the final product can reach up to 98.7%.

[0094] Furthermore, the preparation method of the triglycidyl-4-amino-3-methylphenol epoxy resin of this application, due to the use of a reaction temperature of 30-55℃, especially 40-50℃, in the etherification grafting reaction stage, significantly reduces the occurrence of side reactions and byproducts, resulting in a higher purity of the final product triglycidyl-4-amino-3-methylphenol epoxy resin. According to GPC monitoring, the purity of the final triglycidyl-4-amino-3-methylphenol epoxy resin can reach up to 92.1%, which can directly meet the requirements for adhesives in electronic equipment and automotive products, that is, it can be used directly without further purification, thereby reducing energy consumption in the production process and relatively reducing production costs.

[0095] Furthermore, the method for preparing a triglycidyl-4-amino-3-methylphenol epoxy resin according to this application yields a triglycidyl-4-amino-3-methylphenol epoxy resin. Due to the presence of a methyl group in its structure, this triglycidyl-4-amino-3-methylphenol epoxy resin possesses comparable physicochemical advantages to p-aminophenol or m-aminophenol epoxy resins, while also exhibiting better hydrophobic properties. The final triglycidyl-4-amino-3-methylphenol epoxy resin, cured with methyltetrahydrophthalic anhydride, has a Tg value of 245–250℃ and an impact strength of 25–46 KJ / m. 2 It has a flexural strength of 178–198 MPa, a tensile strength of 70–80 MPa, and a water absorption rate of ≤0.1%.

[0096] Furthermore, the triglycidyl-4-amino-3-methylphenol epoxy resin prepared by the method of this application not only has high purity, but also has excellent high-temperature stability and storage stability. It has relatively low requirements for storage temperature and can be stored for 11 to 15 months without deterioration, while the storage period of commercially available triglycidyl-p-aminophenol epoxy resin or m-aminophenol epoxy resin is only half a year. Detailed Implementation

[0097] The present application will be further described in detail below with reference to specific embodiments, but the embodiments are not intended to limit the present application.

[0098] The raw materials used in the various embodiments of this application are listed in the table below:

[0099]

[0100]

[0101] The methods for determining the performance indicators of the triglycidyl 4-amino-3-methylphenol epoxy resin products obtained in the various embodiments of this application are as follows:

[0102] After curing triglycidyl-4-amino-3-methylphenol epoxy resin (curing method: using methyltetrahydrophthalic anhydride as curing agent and benzyl dimethylamine as accelerator; adding triglycidyl-4-amino-3-methylphenol epoxy resin, curing agent and accelerator sequentially into a container, stirring and mixing evenly at a constant temperature of 20±2℃, an adhesive containing triglycidyl-4-amino-3-methylphenol epoxy resin is obtained; then curing is carried out sequentially at 120℃ for 2 hours and 160℃ for 2 hours, and then data such as Tg, strength and water absorption can be tested):

[0103] The method for determining the Tg value is as follows: The test is performed by DSC method, and the specific steps are as follows: Weigh 5-10 mg of the cured material into an aluminum crucible, raise the temperature at a rate of 10℃ / min, raise the temperature to 300℃, then lower the temperature to 25℃ at a rate of 20℃ / min to eliminate the thermal history, and then raise the temperature again to 300℃ at a programmed temperature of 10℃ / min, and read the glass transition temperature value (Tg).

[0104] The test method for impact strength shall be in accordance with GB / T 2567-2008;

[0105] The test method for bending strength shall be in accordance with GB / T 2567-2008;

[0106] The test method for tensile strength shall be in accordance with GB / T 2567-2008;

[0107] Test method for hydrophobic properties and water absorption rate: Place the product at 85℃ and 85% RH for 1000 hours. The difference in weight before and after the test is the indicator. A large difference indicates poor hydrophobic properties, while a small difference indicates good hydrophobic properties.

[0108] Triglycidyl 4-amino-3-methylphenol epoxy resin:

[0109] Purity determination method: Characterized by gel permeation chromatography (GPC) according to GB / T 27843-2011. The instrument used for determination is Waters high performance liquid chromatograph, model Waters 1515.

[0110] Method for determining epoxy equivalent: GB / T 4612-2008, Instrument model: METTLER TOLEDO;

[0111] Determination of easily saponifiable chlorine: according to GB / T 4618.2-2008;

[0112] The method for determining high-temperature stability is as follows:

[0113] Triglycidyl 4-amino-3-methylphenol epoxy resin was baked at 190°C in an oven for 3 hours, and the change in its purity before and after baking was tested.

[0114] Viscosity determination method: According to GB / T 10247-2008, the viscosity at 25℃ was tested using a digital viscometer (model: Brookfield DV2RT, USA).

[0115] The storage stability determination method for triglycidyl-4-amino-3-methylphenol epoxy resin is as follows: The viscosity data of the triglycidyl-4-amino-3-methylphenol epoxy resin obtained immediately after preparation and after storage at room temperature of 25°C are measured, and the time when the viscosity begins to rise is recorded as the storage period.

[0116] The reaction efficiency of the etherification segment grafting reaction of 4-amino-3-methylphenol during the preparation process was determined by gel permeation chromatography (GPC). The instrument used for the determination was a Waters high performance liquid chromatograph, model Waters 1515.

[0117] The formula for calculating the yield of triglycidyl-4-amino-3-methylphenol epoxy resin is as follows:

[0118] Yield = Mass of actual obtained triglycidyl-4-amino-3-methylphenol epoxy resin ÷ Mass of theoretically generated triglycidyl-4-amino-3-methylphenol epoxy resin × 100%.

[0119] Example 1

[0120] A triglycidyl 4-amino-3-methylphenol epoxy resin, the structural formula of which is shown below:

[0121] ;

[0122] The above-mentioned triglycidyl 4-amino-3-methylphenol epoxy resin is prepared by a method comprising the following steps:

[0123] 1. Etherification grafting reaction

[0124] 1124g of epichlorohydrin, 337g of solvent I, and 166.7g of 4-amino-3-methylphenol (theoretically, this should yield 388g of triglycidyl-4-amino-3-methylphenol epoxy resin) were added sequentially to a 2000ml four-necked round-bottom flask equipped with a stirrer, mercury thermometer, nitrogen inlet tube, condenser, and glass oil-water separator. The mixture was heated to 50℃ and held for 30min to dissolve the 4-amino-3-methylphenol. Then, 61g of catalyst was added (in four portions, 30min apart). The etherification grafting reaction was then carried out at 50℃ for 5h (starting from the first addition of catalyst) to obtain a reaction solution containing 4-amino-3-methylphenol chlorohydrin ether (product A).

[0125] The above-mentioned amounts of 4-amino-3-methylphenol: epichlorohydrin: catalyst, calculated by molar ratio, are 1:9:0.54.

[0126] The 61g catalyst is composed of 2g of dodecyltrimethylammonium chloride and 59g of a sodium hydroxide aqueous solution with a mass percentage concentration of 48.5%. Specifically, the amount of dodecyltrimethylammonium chloride and the sodium hydroxide aqueous solution with a mass percentage concentration of 48.5% is calculated to be 1:29.5 based on the mass ratio of dodecyltrimethylammonium chloride to sodium hydroxide aqueous solution with a mass percentage concentration of 48.5%.

[0127] The ratio of sodium hydroxide in the 4-amino-3-methylphenol catalyst mentioned above is 1:0.53, calculated by molar ratio.

[0128] Solvent I is isopropanol; its amount added is calculated based on the mass ratio of solvent I to epichlorohydrin, which is 30:100.

[0129] (2) Closed-loop reaction

[0130] The reaction solution containing 4-amino-3-methylphenol chlorohydrin ether (product A) obtained in step (1) was adjusted to a pressure of negative 0.089 MPa and a temperature of 40°C. 247 g of sodium hydroxide aqueous solution with a mass percentage concentration of 48.5% was added within 2.5 h, i.e., the addition rate of the sodium hydroxide aqueous solution with a mass percentage concentration of 48.5% was controlled at 1.65 g / min. Then, the reaction was continued at a pressure of negative 0.089 MPa and a temperature of 50°C for 1 h to obtain reaction solution I containing triglycidyl 4-amino-3-methylphenol epoxy resin.

[0131] The above-mentioned amount of sodium hydroxide aqueous solution with a mass percentage concentration of 48.5% is added according to the molar ratio of 4-amino-3-methylphenol to sodium hydroxide in the 48.5% sodium hydroxide aqueous solution of 1:2.2.

[0132] (3) Add 686 ml of solvent II toluene to the reaction solution I containing triglycidyl 4-amino-3-methylphenol epoxy resin obtained in step (2) and stir to dissolve. Then adjust the pressure to a negative pressure of 0.098 MPa and the temperature to 120°C and keep for 2 hours to remove epichlorohydrin and solvent I, and obtain reaction solution II containing triglycidyl 4-amino-3-methylphenol epoxy resin. The solvent II is toluene. The amount of toluene added is based on the theoretically obtainable mass ratio of triglycidyl 4-amino-3-methylphenol epoxy resin according to the amount of toluene: 152:100 based on the amount of 4-amino-3-methylphenol used in step (1).

[0133] (4) Refining reaction

[0134] 35g of sodium hydroxide aqueous solution with a mass percentage concentration of 48.5% was added to the reaction solution II containing triglycidyl 4-amino-3-methylphenol epoxy resin obtained in step (3), and the purification reaction was carried out at 80℃ for 2h to obtain the purified reaction solution, which, in addition to containing triglycidyl 4-amino-3-methylphenol epoxy resin, also contains sodium chloride, solvent II (toluene) and sodium hydroxide aqueous solution, etc.

[0135] The amount of sodium hydroxide aqueous solution with a mass percentage concentration of 40-50% added is 2.5 times the number of moles of easily saponifiable chlorine in the theoretically obtained triglycidyl-4-amino-3-methylphenol epoxy resin;

[0136] (5) Purification

[0137] ① Add 650 ml of water to the purified reaction solution obtained in step (4), mix well, and let stand for 30 min to separate the layers, and obtain the salt water phase and the organic phase composed of resin / solvent II. Remove the lower salt water phase to obtain the organic phase composed of resin / solvent II.

[0138] ② Add 5% oxalic acid aqueous solution to the organic phase composed of resin / solvent II obtained in ① to adjust the pH to 6, and then remove the aqueous phase to obtain the organic phase composed of resin / solvent II with pH 6.

[0139] ③ Add water to the organic phase consisting of resin / solvent II with pH 6 obtained in ② and wash with water. Add 50 ml of water each time. The effluent from the washings does not contain sodium chloride. A crude product containing triglycidyl 4-amino-3-methylphenol epoxy resin and solvent II is obtained.

[0140] ④ The crude product containing triglycidyl-4-amino-3-methylphenol epoxy resin and solvent II obtained in step ③ is subjected to vacuum solvent removal II under controlled pressure of negative pressure 0.0985~0.0995MPa and temperature of 125~140℃ to obtain the finished product of triglycidyl-4-amino-3-methylphenol epoxy resin.

[0141] The product obtained after vacuum removal of solvent II in purification step ④ of step (5) above was subjected to 1H NMR spectroscopy. The results are as follows:

[0142] ( 1 ¹H NMR (400 MHz, CDCl₃): 7.16–7.08 (dd, ¹H, J = 7.6 Hz, 2 Hz, benzene ring hydrogen), 6.80–6.76 (d, ¹H, J = 2 Hz, benzene ring hydrogen), 6.76–6.70 (dd, ¹H, J = 7.6 Hz, 2 Hz, benzene ring hydrogen), 4.20–4.16 (dd, ¹H, J = 8.4 Hz, 2.4 Hz), 3.94–3.90 (dd, 1H, J = 8.8Hz, 4.8Hz), 3.36-3.30 (m, 1H), 3.24-3.00 (m, 6H), 2.92-2.88 (t, 1H, J = 3.6H z), 2.76-2.72 (m, 1H), 2.70-2.66 (m, 2H), 2.45-2.42 (m, 2H), 2.36-2.32 (d, 3H, J = 3.6Hz).

[0143] From the above 1H NMR data, it can be concluded that the product obtained after removing solvent II toluene in purification step ④ of step (5) of the above preparation process is triglycidyl 4-amino-3-methylphenol epoxy resin.

[0144] The reaction efficiency of the etherification grafting reaction of 4-amino-3-methylphenol in step (1) was determined to be 98.5%. The purity of the resulting triglycidyl 4-amino-3-methylphenol epoxy resin product was 92.1%, and the viscosity was 813 cps / 25℃. It could be stored at 25℃ with an air RH humidity of 75% for 15 months, thus exhibiting good storage stability.

[0145] The above-mentioned triglycidyl-4-amino-3-methylphenol epoxy resin, after being baked at 190°C for 3 hours, showed a purity decrease of only 3% (from 92.1% to 89.1%). This indicates that the triglycidyl-4-amino-3-methylphenol epoxy resin of this application has excellent high-temperature stability and can withstand the influence of high environmental temperatures on product performance.

[0146] The above-mentioned triglycidyl-4-amino-3-methylphenol epoxy resin, when combined with a curing agent and an accelerator, exhibits a Tg value of 248℃ and an impact strength of 40 KJ / m after curing. 2 It has a flexural strength of 189 MPa, a tensile strength of 74 MPa, and a water absorption rate of only 0.08%.

[0147] Example 2

[0148] A triglycidyl 4-amino-3-methylphenol epoxy resin is prepared in the same way as in Example 1, except that the catalyst I is dodecyltrimethylammonium chloride.

[0149] The reaction efficiency of the 4-amino-3-methylphenol etherification grafting reaction in step (1) of the preparation process was determined to be 82%. The purity of the obtained triglycidyl 4-amino-3-methylphenol epoxy resin was 86.0%, and the viscosity was 854 cps / 25℃. After curing, the Tg value was 238℃, and the impact strength was 31 KJ / m. 2 It has a flexural strength of 185 MPa, a tensile strength of 71 MPa, and a water absorption rate of 0.09%.

[0150] The obtained triglycidyl 4-amino-3-methylphenol epoxy resin can be stored for 13 months at 25°C and 75% RH humidity.

[0151] Example 3

[0152] A triglycidyl 4-amino-3-methylphenol epoxy resin is prepared in the same manner as in Example 1, except that the catalyst I is a sodium hydroxide aqueous solution with a mass percentage concentration of 48.5%.

[0153] The reaction efficiency of the etherification grafting reaction of 4-amino-3-methylphenol in step (1) of the preparation process was determined to be 75%. The obtained triglycidyl 4-amino-3-methylphenol epoxy resin had a purity of 82.0%, a viscosity of 892 cps / 25℃, and after curing, a Tg value of 233℃ and an impact strength of 24 KJ / m were measured. 2 It has a flexural strength of 181 MPa, a tensile strength of 71 MPa, and a water absorption rate of 0.1%.

[0154] The obtained triglycidyl 4-amino-3-methylphenol epoxy resin can be stored for 13 months at 25°C and 75% RH without deterioration, thus exhibiting excellent storage stability.

[0155] Comparing Examples 1, 2, and 3 above, it can be seen that the catalyst composed of two components in the etherification grafting reaction process can achieve a higher reaction efficiency of etherification grafting between the three active groups (two active hydrogens of the amino group and one active hydrogen of the hydroxyl group) in the 4-amino-3-methylphenol monomer and epichlorohydrin, reaching 98.5% as monitored by GPC. In contrast, the reaction efficiency using a single-component catalyst is only 75-82%. The reason for this may be that the catalyst composed of two components can effectively overcome the effect of the reduced reactivity of the 4-amino-3-methylphenol monomer due to the presence of a methyl group, thereby significantly improving the reaction efficiency of the grafting reaction between the three active groups (two active hydrogens of the amino group and one active hydrogen of the hydroxyl group) in the 4-amino-3-methylphenol monomer and epichlorohydrin.

[0156] Furthermore, comparing the purity of the triglycidyl-4-amino-3-methylphenol epoxy resins obtained in Examples 1, 2, and 3 above, it can be seen that the catalyst composed of two components used in the etherification grafting reaction results in a higher purity of the final triglycidyl-4-amino-3-methylphenol epoxy resin product, which can reach 92.1% as monitored by GPC, and has a higher Tg value after curing. In contrast, the purity of the catalyst using a single component is only 82.0-86.0%, and the Tg value after curing is also lower.

[0157] Example 4

[0158] A triglycidyl 4-amino-3-methylphenol epoxy resin is prepared in the same way as in Example 1, except that the etherification grafting reaction temperature in step (1) is controlled at 55°C.

[0159] The reaction efficiency of the etherification grafting reaction of 4-amino-3-methylphenol in step (1) of the preparation process was determined to be 98.5%, the purity of the obtained triglycidyl 4-amino-3-methylphenol epoxy resin was 90.2%, and the Tg value after curing was 242℃.

[0160] Example 5

[0161] A triglycidyl 4-amino-3-methylphenol epoxy resin is prepared in the same way as in Example 1, except that the etherification grafting reaction temperature in step (1) is controlled at 60°C.

[0162] The reaction efficiency of the etherification grafting reaction of 4-amino-3-methylphenol in step (1) of the preparation process was determined to be 98.6%, the purity of the final triglycidyl 4-amino-3-methylphenol epoxy resin was 85.1%, and the Tg value after curing was 238℃.

[0163] Example 6

[0164] A triglycidyl 4-amino-3-methylphenol epoxy resin is prepared in the same way as in Example 1, except that the etherification grafting reaction temperature in preparation step (1) is controlled at 65°C.

[0165] The reaction efficiency of the etherification grafting reaction of 4-amino-3-methylphenol was determined to be 98.5%, and the purity of the final triglycidyl 4-amino-3-methylphenol epoxy resin was 82.0%, with a Tg value of 236℃ after curing.

[0166] Example 7

[0167] A triglycidyl 4-amino-3-methylphenol epoxy resin is prepared in the same way as in Example 1, except that the etherification grafting reaction temperature in step (1) is controlled at 70°C.

[0168] The reaction efficiency of the etherification grafting reaction of 4-amino-3-methylphenol in step (1) of the preparation process was determined to be 98.6%, the purity of the final triglycidyl 4-amino-3-methylphenol epoxy resin was 79.1%, and the Tg value after curing was 234℃.

[0169] Example 8

[0170] A triglycidyl 4-amino-3-methylphenol epoxy resin is prepared in the same way as in Example 1, except that the etherification grafting reaction temperature in preparation step (1) is controlled at 30°C.

[0171] The reaction efficiency of the etherification grafting reaction of 4-amino-3-methylphenol in step (1) of the preparation process was determined to be 91.0%, the purity of the obtained triglycidyl 4-amino-3-methylphenol epoxy resin was 88.0%, and the Tg value after curing was 240℃.

[0172] Example 9

[0173] A triglycidyl 4-amino-3-methylphenol epoxy resin is prepared in the same way as in Example 3, except that the etherification grafting reaction temperature in preparation step (1) is controlled at 40°C.

[0174] The reaction efficiency of the etherification grafting reaction of 4-amino-3-methylphenol was determined to be 95%, the purity of the obtained triglycidyl 4-amino-3-methylphenol epoxy resin was 90.7%, and the Tg value after curing was 245℃.

[0175] The epoxy equivalent values ​​of the triglycidyl 4-amino-3-methylphenol epoxy resins obtained in Examples 1, 4-9 above were tested, and the results are shown in the table below:

[0176]

[0177] In Examples 1, 4-9 above, when the etherification grafting reaction in step (1) of the preparation process was controlled at temperatures of 50, 55, 60, 65, 70, 30, and 40°C respectively, the purity, epoxy equivalent, and Tg data of the obtained triglycidyl-4-amino-3-methylphenol epoxy resin products showed that the preferred temperature for the etherification grafting reaction was 30-55°C, and more preferably 40-55°C. The reason for this is that when the reaction process is controlled at a lower temperature, side reactions caused by high temperatures can be avoided, which would reduce the purity of the final triglycidyl-4-amino-3-methylphenol epoxy resin product, i.e., increase the epoxy equivalent.

[0178] Example 10

[0179] A triglycidyl 4-amino-3-methylphenol epoxy resin is prepared in the same way as in Example 1, except that the sodium hydroxide aqueous solution with a mass percentage of 48.5% in the composite catalyst used in the etherification grafting reaction of preparation step (1) is added in 5 portions, once every 30 minutes of reaction.

[0180] The reaction efficiency of the etherification grafting reaction of 4-amino-3-methylphenol in step (1) of the preparation process was determined to be 97.9%; the purity of the obtained triglycidyl 4-amino-3-methylphenol epoxy resin was 91.3%, the Tg value after curing was 245℃, and the impact strength was 36KJ / m. 2 The flexural strength is 181 MPa, the tensile strength is 70 MPa, and the water absorption rate is 0.09%. The obtained triglycidyl-4-amino-3-methylphenol epoxy resin can be stored for 14 months at 25°C and 75% RH.

[0181] Example 11

[0182] A triglycidyl 4-amino-3-methylphenol epoxy resin is prepared in the same way as in Example 1, except that the sodium hydroxide aqueous solution with a mass percentage of 48.5% in the composite catalyst used in the etherification grafting reaction of preparation step (1) is added in three portions, once every 30 minutes of reaction.

[0183] The reaction efficiency of the etherification grafting reaction of 4-amino-3-methylphenol in step (1) of the preparation process was determined to be 97.2%; the purity of the obtained triglycidyl 4-amino-3-methylphenol epoxy resin was 90.8%, the Tg value after curing was 244℃, and the impact strength was 35KJ / m. 2The flexural strength is 180 MPa, the tensile strength is 71 MPa, and the water absorption rate is 0.09%. The obtained triglycidyl 4-amino-3-methylphenol epoxy resin can be stored for 14 months at 25°C and 75% RH.

[0184] Example 12

[0185] A triglycidyl-4-amino-3-methylphenol epoxy resin, the preparation process of which is the same as in Example 1, except that:

[0186] The sodium hydroxide aqueous solution with a mass percentage of 48.5% in the composite catalyst used in the etherification grafting reaction of preparation step (1) was added in two portions, once every 30 minutes of the reaction.

[0187] The reaction efficiency of the etherification grafting reaction of 4-amino-3-methylphenol in step (1) of the preparation process was determined to be 95.2%; the purity of the obtained triglycidyl 4-amino-3-methylphenol epoxy resin was 89.0%, the Tg value after curing was 242℃, and the impact strength was 33KJ / m. 2 The flexural strength is 180 MPa, the tensile strength is 72 MPa, and the water absorption rate is 0.1%. The obtained triglycidyl 4-amino-3-methylphenol epoxy resin can be stored for 13 months at 25°C and 75% RH.

[0188] In Examples 1 and 10-12 above, the sodium hydroxide aqueous solution with a mass percentage of 48.5% in the catalyst composed of two components in step (1) of the preparation process was added in 4, 5, 3, and 2 portions, respectively, with an interval of 30 minutes between additions. A comparison of the purity and Tg value of the triglycidyl-4-amino-3-methylphenol epoxy resin obtained in each example shows that the purity and Tg value after curing were best when added in 4 portions. The reason for this is likely that adding in 4 portions can both improve the efficiency of the etherification grafting reaction and maintain a relatively stable temperature within the reaction system.

[0189]

[0190] Example 13

[0191] A triglycidyl 4-amino-3-methylphenol epoxy resin is prepared in the same way as in Example 1, except that the etherification grafting reaction in step (1) of the preparation process is controlled within 3 hours.

[0192] The reaction efficiency of the etherification grafting reaction of 4-amino-3-methylphenol in step (1) of the preparation process was determined to be 86.0%, and the yield of triglycidyl 4-amino-3-methylphenol epoxy resin was 95.5%. The obtained triglycidyl 4-amino-3-methylphenol epoxy resin can be stored for 12 months at 25°C and 75% RH humidity.

[0193] Example 14

[0194] A triglycidyl 4-amino-3-methylphenol epoxy resin, the preparation process of which is the same as in Example 1, except that:

[0195] In the preparation process, step (1) involves etherification grafting reaction, which is controlled within 4 hours.

[0196] The reaction efficiency of the etherification grafting reaction of 4-amino-3-methylphenol in step (1) of the preparation process was determined to be 95.0%, and the yield of triglycidyl 4-amino-3-methylphenol epoxy resin was 98.1%. The obtained triglycidyl 4-amino-3-methylphenol epoxy resin can be stored for 13 months at 25°C and air RH humidity of 75%.

[0197] Example 15

[0198] A triglycidyl 4-amino-3-methylphenol epoxy resin, the preparation process of which is the same as in Example 1, except that:

[0199] In the preparation process, step (1) involves etherification grafting reaction, which is controlled within 6 hours.

[0200] The reaction efficiency of the etherification grafting reaction of 4-amino-3-methylphenol was determined to be 98.6%, and the yield of triglycidyl 4-amino-3-methylphenol epoxy resin was 98.0%. The obtained triglycidyl 4-amino-3-methylphenol epoxy resin can be stored for 14 months at 25°C and 75% RH.

[0201] Example 16

[0202] A triglycidyl 4-amino-3-methylphenol epoxy resin, the preparation process of which is the same as in Example 1, except that:

[0203] In the preparation process, step (1) involves etherification grafting reaction, which is controlled within 8 hours.

[0204] The reaction efficiency of the etherification grafting reaction of 4-amino-3-methylphenol in step (1) of the preparation process was determined to be 98.9%, and the yield of triglycidyl 4-amino-3-methylphenol epoxy resin was 96.5%. The obtained triglycidyl 4-amino-3-methylphenol epoxy resin can be stored for 12.8 months at 25°C and 75% RH humidity.

[0205] The following table summarizes the reaction efficiency of the etherification grafting reaction, the yield of the obtained triglycidyl 4-amino-3-methylphenol epoxy resin, and the storage time at 25°C and 75% RH under different etherification grafting reaction times in Examples 1, 13-16:

[0206]

[0207]

[0208] As can be seen from the table above, the etherification grafting reaction is preferably carried out at a time of 3 to 6 hours, and the reaction efficiency is 86.0 to 98.5%.

[0209] To balance production efficiency, the preferred etherification grafting reaction time is 4–6 hours, which results in a reaction efficiency of 95.0–98.5% and the highest product yield, ranging from 98.1% to 98.7%.

[0210] The triglycidyl 4-amino-3-methylphenol epoxy resins obtained in Examples 13-16 above can be stored for 12, 13, 14, and 12.8 months, respectively, at 25°C and 75% RH humidity.

[0211] Examples 17-19

[0212] A triglycidyl 4-amino-3-methylphenol epoxy resin is prepared in the same way as in Example 1, except that the amount of catalyst used in step (1) etherification grafting reaction is different. That is, when the amounts of 4-amino-3-methylphenol and epichlorohydrin are the same as in Example 1, the amount of catalyst used in Examples 17 to 19 is calculated according to the molar ratio of 4-amino-3-methylphenol: epichlorohydrin: catalyst (the ratio of dodecyltrimethylammonium chloride and sodium hydroxide aqueous solution with a mass percentage concentration of 48.5% in the catalyst is the same as in Example 1) as shown in the table below:

[0213] Meanwhile, the reaction efficiency of the etherification grafting reaction of 4-amino-3-methylphenol in step (1) of the preparation process, the purity and yield of the final triglycidyl 4-amino-3-methylphenol epoxy resin, and the storage time at 25°C and 75% RH humidity are also listed in the table below.

[0214]

[0215] A comparison of the etherification grafting reaction efficiency and the purity of the final triglycidyl 4-amino-3-methylphenol epoxy resin in Examples 1, 17-19 above shows that when the amounts of 4-amino-3-methylphenol and epichlorohydrin are the same, the amount of composite catalyst alone has a significant impact on the etherification grafting reaction efficiency. When the molar ratio of 4-amino-3-methylphenol: epichlorohydrin: catalyst is 1:9:0.54, the etherification grafting reaction has the highest efficiency, the final product has better purity, and the yield is the highest.

[0216] The triglycidyl 4-amino-3-methylphenol epoxy resins obtained in Examples 1, 17-19 above can be stored at 25°C and 75% RH humidity for 11-15 months without deterioration, with a storage period of more than half a year.

[0217] Examples 20-22

[0218] A triglycidyl 4-amino-3-methylphenol epoxy resin is prepared in the same manner as in Example 1, except that the amounts of 4-amino-3-methylphenol and catalyst in step (1) are the same as in Example 1, while the amount of epichlorohydrin is different. Specifically, the amount of epichlorohydrin in Examples 20-22 is calculated based on the molar ratio of 4-amino-3-methylphenol: epichlorohydrin: catalyst, as shown in the table below:

[0219] The reaction efficiency of the etherification grafting reaction of 4-amino-3-methylphenol in step (1) of the preparation process, the purity and yield of the final triglycidyl 4-amino-3-methylphenol epoxy resin, and the storage time at 25°C and 75% RH humidity are also listed in the table below.

[0220]

[0221] A comparison of the reaction efficiency of the etherification grafting reaction in Examples 1, 22-24, and the purity of the final triglycidyl-4-amino-3-methylphenol epoxy resin in the table above shows that the reaction efficiency of the etherification grafting reaction is not significantly affected by the amount of epichlorohydrin, and the impact on the purity of the final product is also minimal. However, in a reactor of the same volume, if the molar amount of epichlorohydrin increases, the amount of 4-amino-3-methylphenol fed will inevitably decrease, resulting in a lower yield of triglycidyl-4-amino-3-methylphenol epoxy resin. Therefore, to maintain a comparable yield, the preferred ratio of 4-amino-3-methylphenol to epichlorohydrin is 1:6-10, calculated by molar ratio.

[0222] The triglycidyl 4-amino-3-methylphenol epoxy resins obtained in Examples 1, 20-22 above can be stored for 14-15 months without deterioration at 25°C and 75% RH humidity.

[0223] Examples 23-25

[0224] A triglycidyl 4-amino-3-methylphenol epoxy resin is prepared in the same way as in Example 1, except that the closed-loop reaction process in steps (2) of Examples 23, 24 and 25 is controlled at 30°C, 45°C and 50°C respectively.

[0225] The content and purity of easily saponifiable chlorine in the triglycidyl-4-amino-3-methylphenol epoxy resins finally obtained in Examples 1, 23-25 ​​were determined, and the results are shown in the table below:

[0226]

[0227] The table above shows the content and purity data of easily saponifiable chlorine in the triglycidyl 4-amino-3-methylphenol epoxy resin. It can be seen that when the closed-ring reaction process is preferably controlled at a temperature of 30-45℃, the content of easily saponifiable chlorine in the finished product is low and the purity of the product is higher, reaching 91.5-92.1%.

[0228] Examples 26-30

[0229] A triglycidyl 4-amino-3-methylphenol epoxy resin is prepared in the same way as in Example 1, except that the addition rate of sodium hydroxide aqueous solution in step (2) of Example 1 and Examples 26-30 is controlled to be 1.65 g / min, 1.45 g / min, 1.85 g / min, 1.25 g / min, 2.05 g / min and 2.25 g / min, respectively.

[0230] The content and purity of easily saponifiable chlorine in the triglycidyl 4-amino-3-methylphenol epoxy resins obtained in Examples 1, 26-30 were determined, and the results are shown in the table below:

[0231]

[0232] The table above shows that the saponifiable chlorine and purity data of triglycidyl 4-amino-3-methylphenol epoxy resin indicate that when the drop rate of the sodium hydroxide aqueous solution with a mass percentage concentration of 48.5% is controlled at 1.45–1.85 g / min during the closed-ring reaction process, the purity of the product is higher, reaching 91.7–92.1%.

[0233] Examples 31-34

[0234] A triglycidyl 4-amino-3-methylphenol epoxy resin, the preparation process of which is the same as in Example 1, except that: in step (2) of Examples 31 to 34, the amount of sodium hydroxide added is controlled in the closed-loop reaction process, and the molar ratio of 4-amino-3-methylphenol to sodium hydroxide in the aqueous solution is 1:2.0, 1:2.3, 1:2.5, and 1:2.7 respectively;

[0235] The results of observing the liquid-liquid separation during purification processes ① in Examples 1 and 31-34, and the purity of the final obtained triglycidyl-4-amino-3-methylphenol epoxy resin are shown in the table below:

[0236]

[0237] From the separation status of ① in the purification process and the purity data of triglycidyl 4-amino-3-methylphenol epoxy resin in the table above, it can be seen that when the molar ratio of 4-amino-3-methylphenol to sodium hydroxide in the aqueous solution is 1:2.2 to 2.3, the separation status is good and the product purity is higher, reaching 91.8% to 92.1%.

[0238] Examples 35-38

[0239] A triglycidyl 4-amino-3-methylphenol epoxy resin is prepared in the same way as in Example 1, except that the purification reaction process in steps (4) of Examples 35 to 38 is controlled at temperatures of 60, 70, 85 and 100°C, respectively.

[0240] The separation conditions during the purification process ① of Examples 1 and 35-38, and the content of easily saponifiable chlorine in the final triglycidyl-4-amino-3-methylphenol epoxy resin, were observed. The results are shown in the table below:

[0241]

[0242]

[0243] As can be seen from the content of readily saponifiable chlorine in the triglycidyl-4-amino-3-methylphenol epoxy resin in the table above, when the temperature is preferably controlled at 70-85℃ during the refining reaction process, the readily saponifiable chlorine in the resin after refining is lower, ranging from 56 to 98 ppm, and the separation effect during the preparation process is also better.

[0244] Examples 39-42

[0245] A triglycidyl 4-amino-3-methylphenol epoxy resin is prepared in the same way as in Example 1, except that the purification reaction process control time in steps (4) of Examples 39, 40, 41 and 42 is 3h, 5h, 7h and 9h respectively, that is, the purification reaction process control time is different.

[0246] The results of observing the liquid-liquid separation during the purification process ① of Examples 1 and 39-42, and the content of easily saponifiable chlorine in the final triglycidyl-4-amino-3-methylphenol epoxy resin are shown in the table below:

[0247]

[0248] As can be seen from the content of easily saponifiable chlorine in the triglycidyl 4-amino-3-methylphenol epoxy resin in the table above, although the content of easily saponifiable chlorine at the end of purification is comparable to that obtained after 7-9 hours when the purification reaction time is controlled at 2-5 hours, the effect of separation in the purification process is better when the time is 2-5 hours.

[0249] Application Example 1

[0250] An adhesive containing the triglycidyl 4-amino-3-methylphenol epoxy resin obtained in Example 1, wherein the raw material composition and content are as follows (by weight): the triglycidyl 4-amino-3-methylphenol epoxy resin obtained in Example 1, the curing agent, and the accelerator are 100 parts, 125 parts, and 0.1 parts, respectively.

[0251] The curing agent mentioned above is methyltetrahydrophthalic anhydride;

[0252] The aforementioned accelerator is benzyl dimethylamine;

[0253] The preparation method of the above-mentioned adhesive containing triglycidyl 4-amino-3-methylphenol epoxy resin includes the following specific steps:

[0254] The above-mentioned triglycidyl 4-amino-3-methylphenol epoxy resin, curing agent and accelerator are added to a container in sequence and stirred and mixed evenly at a constant temperature of 20±2℃ to obtain an adhesive containing triglycidyl 4-amino-3-methylphenol epoxy resin.

[0255] The curing method for the adhesive containing triglycidyl 4-amino-3-methylphenol epoxy resin obtained above is as follows: the curing temperature and curing time are controlled sequentially as follows: 120℃ for 2 hours and 160℃ for 2 hours.

[0256] Comparative example of application example 1

[0257] The epoxy resin used is triglycidyl-p-aminophenol, sourced from Shanghai Huayi Resin Co., Ltd., product brand AFG-90, and its chemical structure is as follows:

[0258]

[0259] The triglycidyl-4-amino-3-methylphenol epoxy resin obtained in Example 1 of Application Example 1 is used as an alternative, and all other aspects are the same as in Application Example 1, ultimately resulting in an adhesive containing triglycidyl-4-aminophenol epoxy resin.

[0260] The curing method for the adhesive containing triglycidyl p-aminophenol epoxy resin described above is the same as the curing method in Application Example 1 described above.

[0261] Application Example 2

[0262] An adhesive containing the triglycidyl 4-amino-3-methylphenol epoxy resin obtained in Example 1, wherein the composition and content of the raw materials used in its preparation are calculated by weight parts, and the triglycidyl 4-amino-3-methylphenol epoxy resin, curing agent, and accelerator obtained in Example 1 are 100 parts, 100 parts, and 0.3 parts, respectively.

[0263] The curing agent described above is the same as that used in Application Example 1;

[0264] The promoters described above are the same as those used in Application Example 1.

[0265] The preparation method and curing method of the above-mentioned triglycidyl 4-amino-3-methylphenol epoxy resin obtained in Example 1 are the same as those in Application Example 1 above.

[0266] Application Example 3

[0267] An adhesive containing triglycidyl 4-amino-3-methylphenol epoxy resin, wherein the raw materials used in its preparation, by weight, are 100 parts of triglycidyl 4-amino-3-methylphenol epoxy resin, 150 parts of curing agent, and 0.6 parts of accelerator.

[0268] The curing agent described above is the same as that used in Application Example 1;

[0269] The promoters described above are the same as those used in Application Example 1.

[0270] The Tg value, impact strength, flexural strength, tensile strength, and water absorption rate of the cured adhesives obtained in Application Example 1 and the Control Example were measured. Simultaneously, the triglycidyl-4-amino-3-methylphenol epoxy resin used in Application Examples 1-3 and the triglycidyl-p-aminophenol epoxy resin used in the Control Example 1 were baked at 190°C for 3 hours, and the changes in their purity were measured, as detailed in the table below.

[0271]

[0272] As can be seen from the table above, the adhesive prepared using the triglycidyl-4-amino-3-methylphenol epoxy resin of this application has a higher Tg value and lower water absorption rate after curing. Furthermore, the triglycidyl-4-amino-3-methylphenol epoxy resin obtained in this application has better high-temperature stability. Therefore, when used for bonding and sealing electronic devices and automobiles that have high requirements for environmental temperature changes, it exhibits higher high-temperature resistance and lower water absorption rate after curing.

[0273] In summary, the triglycidyl-4-amino-3-methylphenol epoxy resin of this application, due to the synergistic effect of various technical means in the preparation process, such as the use of a composite catalyst in the etherification grafting reaction, and the control of specific ratio ranges, specific feeding methods, reaction temperature, and reaction time; the control of the amount and rate of sodium hydroxide aqueous solution in the closed-loop reaction section, and the appropriate pressure and temperature control in the reaction process; and the control of the optimal reaction temperature and time in the purification reaction stage, ultimately yields a high-purity triglycidyl-4-amino-3-methylphenol epoxy resin with a long shelf life. Furthermore, after curing, it also exhibits high temperature resistance and low water absorption. Adhesives prepared using this resin can be widely used for bonding and sealing electronic equipment and automotive products that require strict control over environmental temperature and humidity changes.

[0274] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A method for preparing a triglycidyl-4-amino-3-methylphenol epoxy resin, characterized in that, The structural formula of triglycidyl-4-amino-3-methylphenol epoxy resin is shown below: ， The specific steps of the preparation process are as follows: (1) Etherification grafting reaction In a container, 4-amino-3-methylphenol, epichlorohydrin, catalyst and solvent I are added in sequence, and the reaction is carried out at a temperature of 30-70℃ for 3-8 hours. The above-mentioned amounts of 4-amino-3-methylphenol: epichlorohydrin: catalyst, calculated by molar ratio, are 1:6~15:0.1~0.

6. Solvent I is an alcohol ether co-solvent, which is at least one of ethanol, butanol, ethylene glycol, propylene glycol, isopropanol, ethylene glycol monomethyl ether, propylene glycol monomethyl ether, and tripropylene glycol monomethyl ether. The amount of solvent I used, calculated by mass percentage, is 10-30:100 for solvent I and epichlorohydrin. The catalyst mentioned in step (1) is composed of a quaternary ammonium salt and an alkali metal solution, wherein the quaternary ammonium salt is dodecyltrimethylammonium chloride and the alkali metal solution is a sodium hydroxide aqueous solution with a mass percentage concentration of 40-50%. The amounts of dodecyltrimethylammonium chloride and sodium hydroxide aqueous solution with a mass percentage concentration of 40-50% are calculated by mass ratio, with the ratio of dodecyltrimethylammonium chloride to sodium hydroxide aqueous solution with a mass percentage concentration of 40-50% being 1:28-30. (2) Closed-loop reaction Controlling the negative pressure at 0.07-0.09 MPa and the temperature at 30-50℃, add a sodium hydroxide aqueous solution with a mass percentage concentration of 40-50% to the etherified grafted reaction solution obtained in step (1) to carry out a closed-ring reaction for 2-3 hours to obtain reaction solution I containing triglycidyl 4-amino-3-methylphenol epoxy resin. The amount of sodium hydroxide aqueous solution with a mass percentage concentration of 40-50% used above, calculated by molar ratio, is 1:2.0-2.7 for the molar ratio of 4-amino-3-methylphenol to sodium hydroxide aqueous solution used in step (1). The addition rate of a sodium hydroxide aqueous solution with a mass percentage concentration of 40–50% is 1.25–2.25 g / min; (3) After the closed-loop reaction in step (2) is completed, the pressure is adjusted to a negative pressure of 0.098 MPa and the temperature is raised to 80-125°C to remove solvent I and excess unreacted epichlorohydrin. When the residual amounts of solvent I and unreacted epichlorohydrin are both below 500 ppm, solvent II is added and mixed evenly to obtain reaction solution II containing triglycidyl 4-amino-3-methylphenol epoxy resin. The solvent II is at least one of toluene, xylene, methyl ethyl ketone, and methyl isobutyl ketone, and the amount of solvent II added is 1 to 2.75 times the theoretical mass of triglycidyl 4-amino-3-methylphenol epoxy resin. (4) Refining reaction Add a 40-50% sodium hydroxide aqueous solution to the reaction solution II containing triglycidyl 4-amino-3-methylphenol epoxy resin obtained in step (3), and carry out a purification reaction at a temperature of 60-100℃ for 2-9 hours to obtain the purified reaction solution. The amount of sodium hydroxide aqueous solution with a mass percentage concentration of 40-50% added is 2-4 times the molar number of saponifiable chlorine in reaction solution II containing triglycidyl 4-amino-3-methylphenol epoxy resin. (5) Purification ① Add water to the purified reaction solution obtained in step (4) above, stir and mix well, and let stand to separate into layers to obtain the salt water phase and the organic phase composed of resin / solvent II. Remove the salt water phase. The amount of water added is 3 to 6 times the mass of sodium chloride, a byproduct of the closed-loop reaction in step (2). ② Add a pH adjuster to the organic phase composed of resin / solvent II obtained in ① to adjust the pH value of the organic phase composed of resin / solvent II to 5-7, and then perform separation to remove the aqueous phase, so as to obtain an organic phase composed of resin / solvent II with a pH value of 5-7. The pH adjuster is one of phosphoric acid, sodium hydrogen phosphate, hydrochloric acid, or oxalic acid; ③ Add water to the organic phase composed of resin / solvent II with a pH value of 5-7 obtained in ② and wash until there is no sodium chloride in the effluent to obtain crude product containing triglycidyl 4-amino-3-methylphenol epoxy resin and solvent II. ④ The crude product containing triglycidyl 4-amino-3-methylphenol epoxy resin and solvent II obtained in step ③ is subjected to vacuum heating at a controlled pressure of negative pressure of 0.0985~0.099MPa and a temperature of 125~140℃ to remove solvent II, thereby obtaining triglycidyl 4-amino-3-methylphenol epoxy resin.

2. The method for preparing a triglycidyl-4-amino-3-methylphenol epoxy resin as described in claim 1, characterized in that... The amount of 4-amino-3-methylphenol: epichlorohydrin: catalyst mentioned in step (1) is calculated by molar ratio as 1:6~10:0.1~0.

6.

3. The method for preparing a triglycidyl-4-amino-3-methylphenol epoxy resin as described in claim 2, characterized in that... The amount of sodium hydroxide used in the catalyst described in step (1) is based on a molar ratio of 4-amino-3-methylphenol to sodium hydroxide in an aqueous solution of sodium hydroxide with a mass percentage concentration of 40-50% at 1:0.

53.

4. The method for preparing a triglycidyl-4-amino-3-methylphenol epoxy resin as described in claim 3, characterized in that... The sodium hydroxide aqueous solution with a mass percentage concentration of 40-50% in the catalyst described in step (1) is added in 2-5 portions, with each portion added every 30 minutes.

5. The method for preparing a triglycidyl-4-amino-3-methylphenol epoxy resin as described in claim 4, characterized in that... The sodium hydroxide aqueous solution with a mass percentage concentration of 40-50% in the catalyst described in step (1) is added in 4 portions.

6. The method for preparing a triglycidyl-4-amino-3-methylphenol epoxy resin as described in claim 5, characterized in that... In step (1), the temperature is controlled at 30-55℃ during the etherification grafting reaction.

7. The method for preparing a triglycidyl-4-amino-3-methylphenol epoxy resin as described in claim 6, characterized in that... In step (1), the temperature is controlled at 40-55℃ during the etherification grafting reaction.

8. The method for preparing a triglycidyl-4-amino-3-methylphenol epoxy resin as described in claim 7, characterized in that... In step (1), the etherification grafting reaction takes 3 to 6 hours.

9. The method for preparing a triglycidyl-4-amino-3-methylphenol epoxy resin as described in claim 8, characterized in that... In step (1), the etherification grafting reaction takes 4 to 6 hours.

10. The method for preparing a triglycidyl-4-amino-3-methylphenol epoxy resin as described in claim 9, characterized in that... In step (2) of the closed-loop reaction, the addition rate of sodium hydroxide aqueous solution with a mass percentage concentration of 40-50% is controlled at 1.45-1.85 g / min. The amount of sodium hydroxide aqueous solution with a mass percentage concentration of 40-50% is calculated by molar ratio. The ratio of 4-amino-3-methylphenol to sodium hydroxide in the sodium hydroxide aqueous solution with a mass percentage concentration of 40-50% is 1:2.2-2.

3.

11. The method for preparing a triglycidyl-4-amino-3-methylphenol epoxy resin as described in claim 10, characterized in that... In step (2), the temperature is controlled at 40℃ during the closed-loop reaction.

12. The method for preparing a triglycidyl-4-amino-3-methylphenol epoxy resin as described in claim 11, characterized in that... Step (3) The purification reaction process is carried out at a temperature of 70-85℃ for 2-5 hours.

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