Trifunctional epoxy compound as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of organic synthesis, and relates to a trifunctional epoxy compound as well as a preparation method and application thereof. The trifunctional epoxy compound has a structure as shown in formula (1). Halogenated epoxypropane, tetraethylene glycol and 2, 6-diformaldehyde-4-hydroxypyridine are used as initial raw materials, all halogenated epoxypropane, tetraethylene glycol and 2, 6-diformaldehyde-4-hydroxypyridine have active reaction types and good structural stability, it can be ensured that the reaction activity is fully exerted, the stability of the reaction process is ensured, and the reaction yield is improved. The total yield is favorably improved, so that the efficient synthesis of the trifunctional epoxy compound is realized. In addition, the preparation system of the trifunctional epoxy compound provided by the invention is simple, easy to operate and mild in reaction condition, and the whole reaction system is economical, environment-friendly and efficient. In addition, the trifunctional epoxy compound provided by the invention has unique electron conjugation characteristics and chemical activity, and when the trifunctional epoxy compound is applied to an epoxy adhesive, the epoxy adhesive can be endowed with good toughness. Formula (1)

Description

Technical Field

[0001] This invention belongs to the field of organic synthesis technology, specifically relating to a trifunctional epoxy compound, its preparation method, and its application. Background Technology

[0002] Epoxy compounds play a crucial role in modern industry, widely used in materials, pharmaceuticals, agriculture, and many other sectors. Trifunctional epoxy compounds, in particular, possess three reactive epoxy functional groups due to their unique molecular structure, giving them significant advantages in constructing complex polymer structures and enhancing material performance. They exhibit unique advantages in high-performance materials, adhesives, and coatings. In the field of high-performance materials, trifunctional epoxy compounds, as key monomers, can participate in the formation of highly cross-linked network structures, thereby significantly improving the mechanical strength, thermal stability, and chemical resistance of materials. For example, in the aerospace field, composite materials prepared using trifunctional epoxy compounds can be used to manufacture critical components such as aircraft wings and fuselages, significantly improving load-bearing capacity and reliability while ensuring lightweight materials. In the adhesives and coatings industry, the introduction of trifunctional epoxy compounds can enhance the adhesion of adhesives to different substrates and the wear resistance and corrosion resistance of coatings, making them widely used in fields with stringent coating performance requirements, such as automotive manufacturing and shipbuilding.

[0003] Given the unique advantages of trifunctional epoxy compounds, there is a significant market demand for them. However, existing methods for synthesizing trifunctional epoxy compounds suffer from low yields, thus necessitating the development of a high-yield synthesis method.

[0004] Underfill adhesives are resin adhesives used in electronic packaging processes. They penetrate micron-level gaps through capillary action and are primarily used in semiconductor packaging. Besides filling the gaps between common PCBs and chips, they are also used between flexible printed circuit boards (FPCBs) and chips. Compared to adhesives used between chips and PCBs, those used between chips and FPCBs present greater challenges in formulation design. In addition to possessing the basic properties of conventional underfill adhesives, these adhesives also need to exhibit stronger bonding strength and toughness.

[0005] Epoxy underfillers typically contain epoxy resin, toughening agents, and curing agents. Common epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, and alicyclic epoxy resin. When trifunctional epoxy resin is chosen, the increased epoxy group content generally improves bond strength, but reduces toughness, especially at high temperatures. This is mainly because such epoxy underfillers form a three-dimensional network structure after curing, which restricts molecular chain movement. The increased number of epoxy groups in the epoxy resin leads to higher crosslinking density, further exacerbating this restriction. This makes the material brittle, and the internal stress generated by curing shrinkage cannot be released, easily leading to cracking. Summary of the Invention

[0006] The primary objective of this invention is to provide a novel trifunctional epoxy compound that, when used as the main resin in an epoxy adhesive, can increase the toughness of the epoxy adhesive.

[0007] A second objective of this invention is to provide a method for preparing the aforementioned trifunctional epoxy compound.

[0008] A third objective of this invention is to provide the application of the above-mentioned trifunctional epoxy compounds in adhesives.

[0009] The trifunctional epoxy compound provided by this invention has the structure shown in formula (1): Equation (1), In formula (1), R1 and R2 are each independently H or C1~C5 alkyl groups.

[0010] The method for preparing trifunctional epoxy compounds provided by this invention includes the following steps: S1. The halo-oxidized propylene oxide shown in formula (2) and the triethylene glycol shown in formula (3) are subjected to a first substitution reaction in the presence of base I and catalyst I at a molar ratio of 1:(1-1.1). The resulting intermediate I is subjected to an active group protection reaction in the presence of base II to obtain intermediate II. S2. The 2,6-dicarboxaldehyde-4-hydroxypyridine shown in formula (4) is subjected to a Wittig reaction with phosphorus ylide. The resulting vinyl hydroxypyridine is subjected to a second substitution reaction with intermediate II in the presence of base III and catalyst II. Then, the resulting intermediate III is subjected to an oxidation reaction to obtain a product containing a trifunctional epoxy compound. Equation (2), Equation (3), Equation (4), In equation (2), X is a halogen; In equation (4), R 1 and R 2Each is independently an H or C1-C5 alkyl group.

[0011] This invention uses halopropylene oxide, tetraethylene glycol, and 2,6-dicarboxaldehyde-4-hydroxypyridine as starting materials. Halopropylene oxide, tetraethylene glycol, and 2,6-dicarboxaldehyde-4-hydroxypyridine all possess reactive properties and good structural stability, ensuring full utilization of reactivity and guaranteeing the stability of the reaction process, which is beneficial to improving the overall yield, thus achieving the efficient synthesis of trifunctional epoxy compounds. Furthermore, the preparation system of trifunctional epoxy compounds provided by this invention is simple, easy to operate, and uses mild reaction conditions; the entire reaction system is economical, environmentally friendly, and highly efficient.

[0012] Furthermore, the trifunctional epoxy compound provided by this invention has a tri-tetraethylene glycol structure, a pyridine structure, and three epoxy groups. Two of the epoxy groups are bonded to the carbon atom adjacent to the nitrogen atom on the pyridine ring, and the remaining epoxy group is bonded to the tri-tetraethylene glycol structure. This specific trifunctional epoxy compound has unique electronic conjugation characteristics and chemical activity. When used as the main resin of epoxy adhesives, it can impart good toughness to epoxy adhesives. Detailed Implementation

[0013] The trifunctional epoxy compound provided by this invention has the structure shown in formula (1): Equation (1), In formula (1), R1 and R2 are each independently H or a C1-C5 alkyl group. Examples of C1-C5 alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, tert-pentyl, or neopentyl. Preferably, R1 and R2 are H.

[0014] The method for preparing trifunctional epoxy compounds provided by this invention includes the following steps: S1. Halogenated propylene oxide and tetraethylene glycol are subjected to a first substitution reaction in the presence of base I and catalyst I. The resulting intermediate I is subjected to an active group protection reaction in the presence of base II to obtain intermediate II. S2. 2,6-Dicarboxaldehyde-4-hydroxypyridine and phosphorus ylide are subjected to a Wittig reaction. The resulting vinyl hydroxypyridine is then subjected to a second substitution reaction with intermediate II in the presence of base III and catalyst II. Subsequently, the resulting intermediate III is oxidized to obtain a product containing a trifunctional epoxy compound.

[0015] In the preparation process of the above trifunctional epoxy compounds, the halo-epoxypropane has the structure shown in formula (2): Equation (2), In formula (2), X is a halogen, such as fluorine, chlorine, bromine or iodine.

[0016] In the preparation of the above trifunctional epoxy compound, the triethylene glycol has the structure shown in formula (3): Equation (3).

[0017] In the preparation of the above trifunctional epoxy compound, the 2,6-dicarboxaldehyde-4-hydroxypyridine has the structure shown in formula (4): Equation (4), In equation (4), R 1 and R 2 Each alkyl group is independently H or C1-C5, preferably H. Examples of C1-C5 alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, tert-pentyl, or neopentyl.

[0018] The reaction equations for the preparation of the above trifunctional epoxy compounds are as follows: .

[0019] In the preparation process of the above trifunctional epoxy compound, in step S1, the molar ratio of the halopropylene oxide to triethylene glycol is 1:(1-1.1), such as 1:1, 1:1.01, 1:1.02, 1:1.03, 1:1.04, 1:1.05, 1:1.06, 1:1.07, 1:1.08, 1:1.09, 1:1.1 or any value between them.

[0020] In the preparation process of the above-mentioned trifunctional epoxy compound, in step S1, the molar ratio of the active group protecting agent to triethylene glycol is preferably (0.9-1.1):1, such as 0.9:1, 0.92:1, 0.94:1, 0.96:1, 0.98:1, 1:1, 1.02:1, 1.04:1, 1.06:1, 1.08:1, 1.1:1, or any value between them. The active group protecting agent may include at least one of tert-butyldimethylchlorosilane (TBSCl), trimethylchlorosilane, triethylchlorosilane, triisopropylchlorosilane, dimethylphenylchlorosilane, and tert-butyldiphenylchlorosilane.

[0021] In the preparation process of the above trifunctional epoxy compound, in step S2, the molar ratio of 2,6-dicarboxaldehyde-4-hydroxypyridine to intermediate II is preferably 1:(0.9-1.1), such as 1:0.9, 1:0.92, 1:0.94, 1:0.96, 1:0.98, 1:1, 1:1.02, 1:1.04, 1:1.06, 1:1.08, 1:1.1 or any value between them.

[0022] In the preparation process of the above trifunctional epoxy compound, in step S1, the conditions for the first substitution reaction preferably include a temperature of 50℃-70℃, such as 50℃, 52℃, 55℃, 58℃, 60℃, 62℃, 65℃, 68℃, 70℃ or any value between them; and a time of 10h-24h, such as 10h, 12h, 14h, 16h, 18h, 20h, 22h, 24h or any value between them.

[0023] In the preparation process of the above trifunctional epoxy compound, in step S1, the conditions for the active group protection reaction preferably include a temperature of 10℃-30℃, such as 10℃, 12℃, 15℃, 18℃, 20℃, 22℃, 25℃, 28℃, 30℃ or any value between them; and a time of 5h-12h, such as 5h, 8h, 10h, 12h or any value between them.

[0024] In the preparation process of the above trifunctional epoxy compound, in step S2, the Wittig reaction conditions preferably include a temperature of -20℃ to 0℃, such as -20℃, -18℃, -16℃, -14℃, -12℃, -10℃, -8℃, -6℃, -4℃, -2℃, 0℃ or any value between them; and a time of 1h to 24h, such as 1h, 2h, 4h, 6h, 8h, 10h, 12h, 14h, 16h, 18h, 20h, 22h, 24h or any value between them.

[0025] In the preparation process of the above trifunctional epoxy compound, in step S2, the conditions for the second substitution reaction include a temperature of 25℃-100℃, such as 25℃, 30℃, 35℃, 40℃, 45℃, 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, 90℃, 95℃, 100℃ or any value between them; and a time of 2h-18h, such as 2h, 4h, 6h, 8h, 10h, 12h, 14h, 16h, 18h or any value between them.

[0026] In the preparation process of the above trifunctional epoxy compound, in step S2, the oxidation reaction conditions preferably include a temperature of 40℃-100℃, such as 40℃, 45℃, 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, 90℃, 95℃, 100℃ or any value between them; and a time of 6h-18h, such as 6h, 8h, 10h, 12h, 14h, 16h, 18h or any value between them.

[0027] In a preferred embodiment, in step S1, the method for the first substitution reaction and the active group protection reaction includes dissolving halopropylene oxide, base I, and catalyst I in organic solvent I, heating the resulting mixture to the first substitution reaction temperature under inert gas protection and stirring, then adding tetraethylene glycol trioxide to carry out the first substitution reaction, removing the solvent after the reaction is complete, washing the crude product with water and drying it, then dissolving the obtained intermediate I, base II, and active group protectant in organic solvent II to carry out the active group protection reaction, removing the solvent after the reaction is complete, washing the crude product with water and drying it to obtain intermediate II.

[0028] In a preferred embodiment, step S2, the method for the Wittig reaction, the second substitution reaction, and the oxidation reaction includes dissolving 2,6-dicarboxaldehyde-4-hydroxypyridine and phosphorus ylide in organic solvent III, then reacting at the Wittig reaction temperature under inert gas protection. After the reaction is complete, water is added sequentially for quenching, extraction, solvent removal, and drying to obtain vinylhydroxypyridine. Vinylhydroxypyridine, base III, and catalyst II are dissolved in organic solvent IV, and the temperature is raised to the second substitution reaction temperature under inert gas protection and stirring. Then, intermediate II is added to carry out the second substitution reaction. After the reaction is complete, the solvent is removed to obtain intermediate III. Intermediate III is dissolved in organic solvent V, cooled to -5°C to 5°C, and an oxidant is slowly added. The temperature is then raised to the oxidation reaction temperature to continue the reaction. After the reaction is complete, a product containing a trifunctional epoxy compound is obtained. The phosphorus ylide is generally generated by triphenylmethylphosphorus bromide under the action of a strong base. The strong base may include at least one of n-butyllithium, phenyllithium, potassium tert-butoxide, and sodium tert-butoxide. In the specific reaction process, 2,6-dicarboxaldehyde-4-hydroxypyridine, triphenylmethylphosphorus bromide, and the strong base can be dissolved in organic solvent III, and then the reaction is carried out under inert gas protection at the Wittig reaction temperature.

[0029] The preferred method for preparing trifunctional epoxy compounds provided by the present invention further includes purifying and separating the trifunctional epoxy compounds from the product containing the trifunctional epoxy compounds. The purification method includes adding organic solvent V to the product containing the trifunctional epoxy compounds for dilution, then washing the resulting diluted solution sequentially with saturated sodium bicarbonate aqueous solution and saturated sodium thiosulfate aqueous solution, collecting the organic phase and removing the solvent to obtain the trifunctional epoxy compounds.

[0030] In the preparation of the above-mentioned trifunctional epoxy compound, the types of base I, base II, and base III are not particularly limited and can be conventional choices in the art, as long as they can provide an alkaline environment. For example, they can each be independently selected from at least one of cesium carbonate, sodium bicarbonate, potassium carbonate, potassium hydroxide, sodium hydroxide, and lithium hydroxide. In a preferred embodiment, base I is cesium carbonate or potassium carbonate, base II is triethylamine or sodium hydroxide, and base III is selected from at least one of sodium carbonate, sodium carbonate, potassium hydroxide, and sodium hydroxide. Using the above-mentioned preferred alkaline substances in combination can more effectively promote the formation of reaction products and avoid the formation of by-products, thereby improving the product yield. In addition, the molar ratio of the sum of base I, base II, and base III to halopropylene oxide is preferably (1-5):1, such as 1:1, 1.2:1, 1.5:1, 2:1, 3:1, 3.6:1, 4:1, 4.5:1, 5:1, or any value between them.

[0031] In the preparation of the above trifunctional epoxy compounds, the types of organic solvent I, organic solvent II, organic solvent III, organic solvent IV, and organic solvent V are not particularly limited. They can be any existing inert liquid substances that can be used as reaction media, and can be at least one of alcohol solvents, ester solvents, ether solvents, hydrocarbon solvents, ketone solvents, etc. Specifically, they can be selected from at least one of acetonitrile, dichloromethane, tetrahydrofuran, and N,N-dimethylformamide.

[0032] In the preparation of the above-mentioned trifunctional epoxy compounds, the types of catalysts I and II are not particularly limited, and can be any existing substances that can improve the rate of substitution reactions. Catalyst I can include at least one of benzyltriethylammonium chloride, 18-crown ether-6, tetrabutylammonium chloride, and tetrabutylammonium bromide, with tetrabutylammonium bromide being particularly preferred. Catalyst II can include at least one of 4-dimethylaminopyridine, tetrabutylammonium hydroxide, trioctylmethylammonium chloride, 15-crown ether-5, tetradecyltrimethylammonium chloride, triphenylmethylphosphine bromide, and trioctylmethylphosphine chloride, with 15-crown ether-5 being preferred. When catalysts I and II are selected as the above-mentioned preferred catalysts, it is more beneficial to improve the yield of the trifunctional epoxy compounds.

[0033] In the preparation of the above trifunctional epoxy compounds, the terms "Ⅰ", "Ⅱ", "Ⅲ", "Ⅳ" and "Ⅴ" are merely used to distinguish the same type of substance used in different steps for ease of description, and have no other special meaning.

[0034] In the preparation of the above-mentioned trifunctional epoxy compounds, the type of oxidant is not particularly limited and can be any existing substance that can improve the reaction rate, such as at least one of potassium permanganate, manganese dioxide, potassium peroxymonosulfonate, and m-chloroperoxybenzoic acid (m-CPBA), with m-CPBA being particularly preferred. When m-CPBA is selected as the oxidant, it is more beneficial to improve the yield of the trifunctional epoxy compounds.

[0035] The present invention also provides the application of the trifunctional epoxy compound in adhesives. Specifically, the adhesive contains an epoxy resin, a trifunctional epoxy compound, a toughening agent, a curing agent, and optionally colorants and coupling agents. The mass ratio of the epoxy resin to the trifunctional epoxy compound is preferably 100:(10-300), such as 100:10, 100:20, 100:50, 100:80, 100:100, 100:120, 100:150, 100:180, 100:200, 100:220, 100:250, 100:280, 100:300, or any value between them. The preferred mass ratio of epoxy resin to toughening agent is 100:(20-300), such as 100:20, 100:50, 100:80, 100:100, 100:120, 100:150, 100:180, 100:200, 100:220, 100:250, 100:280, 100:300 or any value between them. The preferred mass ratio of epoxy resin to curing agent is 100:(20-500), such as 100:20, 100:50, 100:80, 100:100, 100:120, 100:150, 100:180, 100:200, 100:220, 100:250, 100:280, 100:300, 100:320, 100:350, 100:380, 100:400, 100:420, 100:450, 100:480, 100:500, or any value between them. The preferred mass ratio of epoxy resin to colorant is 100:(0-20), such as 0, 100:1, 100:2, 100:4, 100:6, 100:8, 100:10, 100:12, 100:14, 100:16, 100:18, 100:20, or any value between them. The preferred mass ratio of epoxy resin to coupling agent is 100:(0-100), such as 0, 100:2, 100:5, 100:10, 100:13, 100:15, 100:18, 100:20, 100:50, 100:80, 100:100, or any value between them.

[0036] In the epoxy resin composition, the curing agent can be a conventional acid anhydride curing agent, preferably containing at least a cyclic acid anhydride compound, and can be only a cyclic acid anhydride compound, or a mixture of a cyclic acid anhydride compound and a conventional acid anhydride curing agent. Preferably, the cyclic acid anhydride compound accounts for 10-100% of the total weight of the curing agent, more preferably 20-100%, further preferably 30-100%, further preferably 40-100%, further preferably 50-100%, further preferably 60-100%, further preferably 70-100%, further preferably 80-100%, further preferably 90-100%, and most preferably 100%. A higher proportion of the cyclic acid anhydride compound is more beneficial for improving the bonding strength. The conventional anhydride curing agents may include at least one of the following: methylnadic anhydride, methylbicyclo[2.2.1]heptane-2,3-dicarboxylic anhydride, bicyclo[2.2.1]heptane-2,3-dicarboxylic anhydride, hexahydro-4-methylphthalic anhydride (MHHPA), methyltetrahydrophthalic anhydride (MTHPA), methylcyclohexene-1,2-dicarboxylic anhydride, methylbicyclo[2.2.1]heptane-2,3-dicarboxylic anhydride, bicyclo[2.2.1]heptane-2,3-dicarboxylic anhydride, (2-dodecen-1-yl)succinic anhydride, glutaric anhydride, citrate anhydride, methylsuccinic anhydride, 2,2-dimethylsuccinic anhydride, 2,2-dimethylglutaric anhydride, 3-methylglutaric anhydride, 3,3-tetramethyleneglutaric anhydride, and 3,3-dimethylglutaric anhydride.

[0037] In the epoxy resin composition, the curing agent cyclic anhydride compound has the structure shown in formula (1'): Equation (1'), In equation (1), R1, R2, R3, R4, R5, R6, R7, R8, R9, R 10 R 11 R 12 R 13 and R 14 Each of the alkyl groups is independently H or C1-C6. Examples of C1-C6 alkyl groups include: methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, tert-pentyl, or neopentyl.

[0038] In the epoxy resin composition, the cyclic anhydride compound preferably has a symmetrical structure, in which case R1, R7, R8, and R... 14 The same applies to R2, R6, R9, and R... 13Same, R3, R5, R 10 and R 12 Same, R4 and R 11 The same. When cyclic anhydride compounds have a symmetrical structure, the overall structure after curing can be guaranteed to be stable and not easily affected by external conditions (such as temperature changes), resulting in higher high-temperature adhesive strength. In a preferred embodiment, in formula (1'), R1, R2, R3, R4, R5, R6, R7, R8, R9, R 10 R 11 R 12 R 13 and R 14 All are H.

[0039] The present invention will be further described below with reference to the embodiments.

[0040] In the following examples and comparative examples, bisphenol F diglycidyl ether was purchased from Mitsubishi Chemical Corporation, grade 806, with an epoxy equivalent of 160 g / eq; bisphenol A diglycidyl ether was purchased from Mitsubishi Chemical Corporation, grade 828, with an epoxy equivalent of 184 g / eq; and SBS thermoelastic resin was purchased from Kraton, grade D1155.

[0041] Example 1: Preparation of trifunctional epoxy compounds S1. 9.2 g (0.1 mol, 1 eq) of epichlorohydrin was dissolved in 200 mL of acetonitrile, followed by the addition of 41.5 g (0.3 mol, 3.05 eq) of potassium carbonate and 3.2 g (0.01 mol, 0.1 eq) of tetrabutylammonium bromide. The mixture was heated to 60 °C and stirred for 20 min under inert gas protection. Then, 19.4 g (0.1 mol, 1 eq) of tetraethylene glycol was slowly added and the mixture was reacted for 12 h. The solvent was then recovered by vacuum distillation, followed by washing with water and drying to obtain 23 g of intermediate I. 23 g (91 mmol, 1 eq) of intermediate I was dissolved in 200 mL of dichloromethane. After nitrogen purging, 13.8 g (136.5 mmol, 1.5 eq) of triethylamine and 15 g (0.1 mol, 1 eq) of TBSCl were added. The mixture was stirred at 10 °C for 6 h. After the reaction was completed, the solvent was removed by vacuum distillation. The crude product was washed with water and dried to obtain 27 g of intermediate II.

[0042] S2. 15.1 g (0.1 mol, 1 eq) of 2,6-dicarboxaldehyde-4-hydroxypyridine was dissolved in 200 mL of tetrahydrofuran, cooled to 0 °C, and 6.4 g (0.1 mol, 1 eq) of n-butyllithium and 37.3 g (0.11 mol, 1.1 eq) of triphenylmethylphosphorus bromide were added under argon protection. The mixture was stirred for 1 h, and after the reaction was completed, it was quenched with water. The mixture was then extracted with 200 mL of dichloromethane, and the organic phase was distilled under reduced pressure to remove the solvent, yielding 12 g of 2,6-diethylene-4-hydroxypyridine. 12 g (80 mmol, 1 eq) of 2,6-diethylene-4-hydroxypyridine was dissolved in 160 mL of N,N-dimethylformamide, followed by the addition of 33.7 g (244 mmol, 3.05 eq) of potassium carbonate and 1 g (DMAP, 8 mmol, 0.1 eq) of 4-dimethylaminopyridine. After heating to 70 °C, 40 g (0.11 mol, 1.1 eq) of intermediate II was slowly added. After the addition was complete, the reaction was stirred for 8 h. After the reaction was completed, water was added to quench the reaction, and the solvent was removed by extraction and vacuum distillation to obtain 40.2 g of intermediate III. 40.2 g (84 mmol, 1 eq) of intermediate III was dissolved in 160 mL of dichloromethane, cooled to 0 °C, and 43.5 g (252 mmol, 3 eq) of m-CPBA was slowly added. The temperature was then raised to 40 °C, and the reaction was continued at this temperature for 12 h. The solution was then diluted with dichloromethane and washed three times with saturated sodium bicarbonate aqueous solution and two times with saturated sodium thiosulfate aqueous solution. The organic phase was collected and evaporated to dryness to obtain 36.9 g of trifunctional epoxy compound, denoted as EP-1.

[0043] The overall yield of the reaction was 72.1%. The NMR results are as follows: 1 H NMR (400 MHz, DMSO-d6) δ 7.05(s, 2H), 4.16 (dt, J = 12.3, 6.1 Hz, 1H), 4.02 (dt, J = 12.4, 6.2 Hz, 1H), 3.94(t, J =5.1 Hz, 2H), 3.82 (dt, J = 12.4, 6.2 Hz, 1H), 3.77 -3.71 (m, 3H), 3.74-3.55 (m, 15H), 3.42 (dd, J = 7.2, 5.5 Hz, 1H), 2.97 (dd, J = 7.2, 5.5 Hz, 1H), 2.89 (p, J=5.6 Hz, 1H). The NMR results show that the trifunctional epoxy compound has the structure shown in formula (1).

[0044] Example 2 Preparation of trifunctional epoxy compounds S1. 46 g (0.5 mol, 1 eq) of epichlorohydrin was dissolved in 1 L of acetonitrile, followed by the addition of 207.3 g (1.5 mol, 3.05 eq) of potassium carbonate and 16 g (0.05 mol, 0.1 eq) of tetrabutylammonium bromide. The mixture was heated to 50 °C and stirred for 20 min under inert gas protection. Then, 97 g (0.5 mol, 1 eq) of tetraethylene glycol was slowly added and the mixture was reacted for 24 h. The solvent was then recovered by vacuum distillation, followed by washing with water and drying to obtain 107 g of intermediate I. 107 g (0.42 mol, 1 eq) of intermediate I was dissolved in 1 L of dichloromethane. After nitrogen purging, 63.7 g (0.63 mol, 1.5 eq) of triethylamine and 63.3 g (0.42 mol, 1 eq) of TBSCl were added. The mixture was stirred at 30 °C for 5 h. After the reaction was completed, the solvent was removed by vacuum distillation. The crude product was washed with water and dried to obtain 119 g of intermediate II.

[0045] S2. 75.5 g (0.5 mol, 1 eq) of 2,6-dicarboxaldehyde-4-hydroxypyridine was dissolved in 1 L of tetrahydrofuran, cooled to -20 °C, and 32 g (0.5 mol, 1 eq) of n-butyllithium and 188.76 g (0.55 mol, 1.1 eq) of triphenylphosphine bromide were added under argon protection. The mixture was stirred for 24 h. After the reaction was completed, the mixture was quenched with water, extracted with 500 mL of dichloromethane, and the organic phase was then distilled under reduced pressure to remove the solvent, yielding 62 g of 2,6-diethylene-4-hydroxypyridine. 62 g (0.41 mol, 1 eq) of 2,6-diethylene-4-hydroxypyridine was dissolved in 800 mL of N,N-dimethylformamide, followed by the addition of 33.7 g (1.25 mol, 3.05 eq) of potassium carbonate and 4.9 g (40.1 mmol, 0.1 eq) of DMAP. The temperature was maintained at 25 °C, and then 112.8 g (0.45 mol, 1.1 eq) of intermediate II was slowly added. After the addition was complete, the reaction was stirred for 18 h. After the reaction was completed, water was added to quench the reaction, and the solvent was removed by extraction and vacuum distillation to obtain 204 g of intermediate III. 204 g (0.43 mol, 1 eq) of intermediate III was dissolved in 800 mL of dichloromethane, cooled to 0 °C, and 220.8 g (1.28 mol, 3 eq) of m-CPBA was slowly added. The temperature was raised to 60 °C, and the reaction was continued at this temperature for 18 h. Then, dichloromethane was added to dilute the solution, and the solution was washed three times with saturated sodium bicarbonate aqueous solution and then twice with saturated sodium thiosulfate aqueous solution. The organic phase was collected and evaporated to dryness to obtain 172 g of trifunctional epoxy compound, denoted as EP-2.

[0046] The overall yield of the reaction was 67.4%. The NMR results are as follows: 1 H NMR (400 MHz, DMSO-d6) δ 7.05(s, 2H), 4.16 (dt, J = 12.3, 6.1 Hz, 1H), 4.02 (dt, J = 12.4, 6.2 Hz, 1H), 3.94(t, J =5.1 Hz, 2H), 3.82 (dt, J = 12.4, 6.2 Hz, 1H), 3.77 -3.71 (m, 3H), 3.74-3.55 (m, 15H), 3.42 (dd, J = 7.2, 5.5 Hz, 1H), 2.97 (dd, J = 7.2, 5.5 Hz, 1H), 2.89 (p, J=5.6 Hz, 1H). The NMR results show that the trifunctional epoxy compound has the structure shown in formula (1).

[0047] Example 3 Preparation of trifunctional epoxy compounds S1. 92 g (1 mol, 1 eq) of epichlorohydrin was dissolved in 2 L of acetonitrile, followed by the addition of 414.6 g (3 mol, 3.05 eq) of potassium carbonate and 32 g (0.1 mol, 0.1 eq) of tetrabutylammonium bromide. The mixture was heated to 70 °C and stirred for 20 min under inert gas protection. Then, 213 g (1.1 mol, 1.1 eq) of tetraethylene glycol was slowly added and the mixture was reacted for 10 h. The solvent was then recovered by vacuum distillation, washed with water, and dried to obtain 240 g of intermediate I. 240 g (0.6 mol, 1 eq) of intermediate I was dissolved in 1200 mL of dichloromethane. After nitrogen purging, 91 g (0.9 mol, 1.5 eq) of triethylamine and 90.4 g (0.6 mol, 1 eq) of TBSCl were added. The mixture was stirred at 20 °C for 12 h. After the reaction was complete, the solvent was removed by vacuum distillation. The crude product was washed with water and dried to obtain 290 g of intermediate II.

[0048] S2. 151.1 g (1 mol, 1 eq) of 2,6-dicarboxaldehyde-4-hydroxypyridine was dissolved in 2 L of tetrahydrofuran, cooled to -10 °C, and 64 g (1 mol, 1 eq) of n-butyllithium and 377.5 g (1.1 mol, 1.1 eq) of triphenylphosphine bromide were added under argon protection. The mixture was stirred for 10 h. After the reaction was completed, water was added to quench the reaction, followed by extraction with 800 mL of dichloromethane. The organic phase was then distilled under reduced pressure to remove the solvent, yielding 140 g of 2,6-diethylene-4-hydroxypyridine. 140 g (0.94 mol, 1 eq) of 2,6-diethylene-4-hydroxypyridine was dissolved in 1.6 L of N,N-dimethylformamide, followed by the addition of 1.3 kg (9.38 mol, 3.05 eq) of potassium carbonate and 10 g (80 mmol, 0.1 eq) of DMAP. After heating to 100 °C, 400 g (1.1 mol, 1.1 eq) of intermediate II was slowly added. After the addition was complete, the mixture was stirred for 2 h. After the reaction was completed, water was added to quench the reaction, and the solvent was removed by extraction and vacuum distillation to obtain 410 g of intermediate III. 410 g (0.86 mol, 1 eq) of intermediate III was dissolved in 1600 mL of dichloromethane, cooled to 0 °C, and 445 g (2.58 mol, 3 eq) of m-CPBA was slowly added. The temperature was raised to 100 °C, and the reaction was continued at this temperature for 6 h. Then, dichloromethane was added to dilute the solution, and the solution was washed three times with saturated sodium bicarbonate aqueous solution and then twice with saturated sodium thiosulfate. The organic phase was collected and evaporated to dryness to obtain 382 g of trifunctional epoxy compound, denoted as EP-1.

[0049] The overall yield of the reaction was 74.8%. The NMR results are as follows: 1 H NMR (400 MHz, DMSO-d6) δ 7.05(s, 2H), 4.16 (dt, J = 12.3, 6.1 Hz, 1H), 4.02 (dt, J = 12.4, 6.2 Hz, 1H), 3.94(t, J =5.1 Hz, 2H), 3.82 (dt, J = 12.4, 6.2 Hz, 1H), 3.77 -3.71 (m, 3H), 3.74-3.55 (m, 15H), 3.42 (dd, J = 7.2, 5.5 Hz, 1H), 2.97 (dd, J = 7.2, 5.5 Hz, 1H), 2.89 (p, J=5.6 Hz, 1H). The NMR results show that the trifunctional epoxy compound has the structure shown in formula (1).

[0050] Example 4 Preparation of cyclic acid anhydride compounds S1`. A polyhydroxy aromatic compound (having the structure shown in formula (II), R3, R4, R5, R 10 R 11 and R 12 All of the above (0.6 g, 3.0 mmol) were dissolved in methanol (30 mL), and KOH (1.0 g, 18 mmol) was added. The mixture was stirred until clear, and acrylonitrile (2.4 mL, 36 mmol) was added dropwise under ice bath conditions. The mixture was stirred at 20 °C for 24 h. After the reaction was completed, the reaction was quenched with water. The resulting product was then extracted three times with dichloromethane. The organic phase was washed successively with saturated NaCl solution, dried over anhydrous Na2SO4, the organic solvent was removed under reduced pressure, and purified by column chromatography to obtain a polycyano aromatic compound (white solid).

[0051] S2. Dissolve the polycyano aromatic compound (0.73 g, 1.5 mmol) in methanol (20 mL), add concentrated hydrochloric acid (5 mL), and reflux for 12 h. After the reaction is complete, remove the methanol by rotary evaporation, dissolve the residue in water, extract three times with dichloromethane, acidify the aqueous phase to pH 2 with concentrated hydrochloric acid, precipitate a white solid, filter, and dry to obtain the polycarboxylic aromatic compound.

[0052] S3. A polycarboxylated aromatic compound (0.34 g, 0.7 mmol) was dissolved in dichloromethane (20 mL), and DCC (0.3 g, 1.5 mmol) was added. The mixture was stirred at 25 °C for 24 h. After the reaction was complete, dicyclohexylurea was removed by filtration, and the filtrate was concentrated by rotary evaporation and purified by column chromatography to give 0.25 g of a cyclic anhydride compound (white solid, denoted as AH-1), with a yield of 80%.

[0053] The NMR data and characteristic data of this cyclic anhydride compound are as follows: 1 H NMR (400 MHz, DMSO-d6) δ7.20 (p, J = 1.0 Hz, 2H), 4.57 (d, J = 1.0 Hz, 8H), 3.75 (t, J = 7.1 Hz, 8H), 2.62(t, J = 7.1 Hz, 8H). From the above results, it can be seen that this cyclic anhydride compound has the structure shown in formula (1'), and R1, R2, R3, R4, R5, R6, R7, R8, R9, R... 10 R 11 R12 R 13 and R 14 All are H.

[0054] Test Example 1 25 parts by weight of bisphenol A diglycidyl ether, 10 parts by weight of bisphenol F diglycidyl ether, 19 parts by weight of trifunctional epoxy compound (EP-1), 20 parts by weight of SBS thermoelastic resin, 20 parts by weight of methyl nadic anhydride, 1 part by weight of carbon black, and 5 parts by weight of γ-epoxypropoxypropyltrimethoxysiloxane were stirred and mixed in a dual planetary hybrid stirring vessel for 30 min. The vessel walls were scraped every 10 min of stirring, and then stirring was continued. After the micelles were mixed, vacuum degassing was started while stirring was started. After vacuum degassing for 10 min, the material was discharged to obtain the epoxy resin composition.

[0055] (1) Viscosity: The viscosity of the epoxy resin composition was tested using a BROOKFIELD viscometer immediately after preparation and after standing for 24 hours. The test conditions included: at room temperature, the viscosity data was measured after rotating a 29# rotor at 5 rpm for 30 minutes. The results are shown in Table 1.

[0056] (2) Elongation at break: After curing the epoxy resin composition, dog bone samples were made and stretched on a DMA instrument in tensile mode. The temperature was heated to 245°C at room temperature and held for 1 min. The load was increased to 18 N at 5 N / min. The results are shown in Table 1.

[0057] (3) Adhesive strength: The epoxy resin composition was coated on a silicon wafer and then pressed onto an FR5 substrate to make a test sample. The bonding area was 2mm × 2mm and the adhesive layer thickness was 50μm. The sample was cured at 150℃ for 120min. The cured sample was then pushed sideways using a Dage 4000 and tested at a high temperature (260℃). The measured force value was recorded as the high-temperature adhesive strength (MPa). After curing, the sample was treated with heating and humidification conditions of 85℃ / 85%RH for 120h and then tested for adhesive strength at a high temperature (260℃). The measured force value was recorded as the aging high-temperature adhesive strength (MPa). The results are shown in Table 1.

[0058] Test Example 2 25 parts by weight of bisphenol A diglycidyl ether, 25 parts by weight of bisphenol F diglycidyl ether, 5 parts by weight of trifunctional epoxy compound (EP-2), 10 parts by weight of SBS thermoelastic resin, 30 parts by weight of methyl nadic anhydride, 1 part by weight of carbon black, and 1 part by weight of γ-epoxypropoxypropyltrimethoxysiloxane were stirred and mixed in a dual planetary hybrid stirring vessel for 30 minutes. The vessel walls were scraped every 10 minutes of stirring, and then stirring was continued. After the micelles were mixed, vacuum degassing was started while stirring was started. After vacuum degassing for 10 minutes, the material was discharged to obtain the epoxy resin composition.

[0059] The viscosity, elongation at break, and bond strength of the epoxy resin composition were tested according to the method in Test Example 1, and the results are shown in Table 1.

[0060] Test Example 3 Four parts by weight of bisphenol A diglycidyl ether, 10 parts by weight of bisphenol F diglycidyl ether, 30 parts by weight of trifunctional epoxy compound (EP-3), 30 parts by weight of SBS thermoelastic resin, 15 parts by weight of methyl nadic anhydride, 1 part by weight of carbon black, and 10 parts by weight of γ-epoxypropoxypropyltrimethoxysiloxane were stirred and mixed in a dual planetary hybrid stirring vessel for 30 min. The vessel walls were scraped every 10 min of stirring, and then stirring was continued. After the micelles were mixed, vacuum degassing was started while stirring was started. After vacuum degassing for 10 min, the material was discharged to obtain the epoxy resin composition.

[0061] The viscosity, elongation at break, and bond strength of the epoxy resin composition were tested according to the method in Test Example 1, and the results are shown in Table 1.

[0062] Test Example 4 An epoxy resin composition was prepared according to the method of Test Example 1, except that the methyl nadic anhydride was replaced by the same amount of cyclic anhydride compound AH-1 obtained in Example 4, and the other conditions were the same as in Test Example 1, to obtain the epoxy resin composition.

[0063] The viscosity, elongation at break, and bond strength of the epoxy resin composition were tested according to the method in Test Example 1, and the results are shown in Table 1.

[0064] Comparative Test Case 1 An epoxy resin composition was prepared according to the method of Test Example 1, except that the trifunctional epoxy compound was replaced with the same amount of bisphenol A bisglycidyl ether by weight, and the other conditions were the same as in Test Example 1, to obtain the epoxy resin composition.

[0065] The viscosity, elongation at break, and bond strength of the epoxy resin composition were tested according to the method in Test Example 1, and the results are shown in Table 1.

[0066] Table 1

[0067] As can be seen from the results of the examples, the total yield of trifunctional epoxy compounds prepared by the method provided by the present invention can reach more than 67.4%, which can realize the efficient synthesis of trifunctional epoxy compounds.

[0068] As can be seen from the results in Table 1, the epoxy resin compositions provided in Test Examples 1-4, which contain a trifunctional epoxy compound with the structure shown in Formula (1), exhibit an elongation at break of over 2.2%. The only difference between Test Example 1 and Test Example 4 is that Test Example 1 does not contain a trifunctional epoxy compound with the structure shown in Formula (1), resulting in an elongation at break of only 1.5%. This demonstrates that the trifunctional epoxy compound with the structure shown in Formula (1) can impart good toughness to the epoxy resin composition. A comparison between Test Example 1 and Test Example 4 shows that when the curing agent contains a cyclic anhydride compound with the structure shown in Formula (1'), it can impart higher high-temperature adhesive strength to the epoxy resin composition without significantly affecting its toughness.

[0069] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. A trifunctional epoxy compound, characterized in that, The trifunctional epoxy compound has the structure shown in formula (1): Equation (1), In equation (1), R 1 and R 2 Each is independently an H or C1-C5 alkyl group.

2. The trifunctional epoxy compound according to claim 1, characterized in that, In equation (1), R1 and R2 are H.

3. The method for preparing the trifunctional epoxy compound according to claim 1 or 2, characterized in that, The method includes the following steps: S1. The halo-oxidized propylene oxide shown in formula (2) and the triethylene glycol shown in formula (3) are subjected to a first substitution reaction in the presence of base I and catalyst I at a molar ratio of 1:(1-1.1). The resulting intermediate I is subjected to an active group protection reaction in the presence of base II to obtain intermediate II. S2. The 2,6-dicarboxaldehyde-4-hydroxypyridine shown in formula (4) is subjected to a Wittig reaction with phosphorus ylide. The resulting vinyl hydroxypyridine is subjected to a second substitution reaction with intermediate II in the presence of base III and catalyst II. Then, the resulting intermediate III is subjected to an oxidation reaction to obtain a product containing a trifunctional epoxy compound. Equation (2), Equation (3), Equation (4), In equation (2), X is a halogen; In equation (4), R 1 and R 2 Each is independently an H or C1-C5 alkyl group.

4. The method for preparing the trifunctional epoxy compound according to claim 3, characterized in that, In step S1, the method for the first substitution reaction and the active group protection reaction includes dissolving halopropylene oxide, base I, and catalyst I in organic solvent I, heating the resulting mixture to the first substitution reaction temperature under inert gas protection and stirring, then adding tetraethylene glycol trioxide to carry out the first substitution reaction, removing the solvent after the reaction is complete, washing the crude product with water and drying it, then dissolving the obtained intermediate I, base II, and active group protectant in organic solvent II to carry out the active group protection reaction, removing the solvent after the reaction is complete, washing the crude product with water and drying it to obtain intermediate II.

5. The method for preparing the trifunctional epoxy compound according to claim 4, characterized in that, In step S2, the Wittig reaction, the second substitution reaction, and the oxidation reaction are performed by dissolving 2,6-dicarboxaldehyde-4-hydroxypyridine and phosphorus ylide in organic solvent III, and then reacting at the Wittig reaction temperature under inert gas protection. After the reaction is completed, water is added to quench the reaction, extract the solution, remove the solvent, and dry the solution to obtain vinyl hydroxypyridine. Vinyl hydroxypyridine, base III, and catalyst II are dissolved in organic solvent IV, and the temperature is raised to the second substitution reaction temperature under inert gas protection and stirring. Then, intermediate II is added to carry out the second substitution reaction. After the reaction is completed, the solvent is removed to obtain intermediate III. Intermediate III is dissolved in organic solvent V, cooled to -5℃ to 5℃, and then an oxidant is slowly added. The temperature is then raised to the oxidation reaction temperature to continue the reaction. After the reaction is completed, a product containing a trifunctional epoxy compound is obtained. Preferably, the phosphorus ylide is generated by triphenylmethylphosphorus bromide under the action of a strong base; Preferably, the strong base is selected from at least one of n-butyllithium, phenyllithium, potassium tert-butoxide, and sodium tert-butoxide.

6. The method for preparing the trifunctional epoxy compound according to claim 3, characterized in that, The method for preparing the trifunctional epoxy compound further includes purifying and separating the trifunctional epoxy compound from the product containing the trifunctional epoxy compound. The purification method includes adding organic solvent VI to the product containing the trifunctional epoxy compound for dilution, then washing the resulting diluted solution sequentially with saturated sodium bicarbonate aqueous solution and saturated sodium thiosulfate aqueous solution, collecting the organic phase and removing the solvent to obtain the trifunctional epoxy compound.

7. The method for preparing the trifunctional epoxy compound according to any one of claims 3 to 6, characterized in that, In step S1, the conditions for the first substitution reaction include a temperature of 50℃-70℃ and a time of 10h-24h; the conditions for the active group protection reaction include a temperature of 10℃-30℃ and a time of 5h-12h.

8. The method for preparing the trifunctional epoxy compound according to any one of claims 3 to 6, characterized in that, In step S2, the conditions for the Wittig reaction include a temperature of -20℃ to 0℃ and a time of 1h to 24h; the conditions for the second substitution reaction include a temperature of 25℃ to 100℃ and a time of 2h to 18h; and the conditions for the oxidation reaction include a temperature of 40℃ to 100℃ and a time of 6h to 18h.

9. The method for preparing the trifunctional epoxy compound according to any one of claims 3 to 6, characterized in that, The base I is cesium carbonate or potassium carbonate; the base II is triethylamine or sodium hydroxide; and the base III is selected from at least one of sodium carbonate, sodium carbonate, potassium hydroxide, and sodium hydroxide.

10. The use of the trifunctional epoxy compound of claim 1 or 2 in adhesives.

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