Trifunctional epoxy resin compound, preparation method and application thereof, and epoxy adhesive

Abstract

The invention belongs to the technical field of organic synthesis, and relates to a trifunctional epoxy resin compound, a preparation method and application thereof, and an epoxy adhesive. The preparation method of the trifunctional epoxy resin compound comprises the following steps: performing a first nucleophilic substitution reaction on alkenyl phenol and first halogenated alkene, performing a Claisen rearrangement reaction on a product of the first nucleophilic substitution reaction, and performing a second nucleophilic substitution reaction on a product of the Claisen rearrangement reaction and second halogenated alkene and / or halogenated epoxypropane to obtain the trifunctional epoxy resin compound. And carrying out oxidation reaction on the second nucleophilic substitution reaction product to convert the double bond into an epoxy group, thereby obtaining the trifunctional epoxy resin compound. The trifunctional epoxy resin compound prepared by adopting the method provided by the invention is relatively high in total yield, relatively low in cost and relatively environment-friendly. In addition, the epoxy adhesive containing the trifunctional epoxy resin compound provided by the invention has low viscosity and good heat resistance, and has wide application prospects.

Description

Technical Field

[0001] The invention belongs to the technical field of organic synthesis, and particularly relates to a trifunctional epoxy resin compound, a preparation method and application thereof, and an epoxy adhesive. Background Art

[0002] Epoxy resins generally refer to organic polymers containing two or more epoxy groups within the molecule. With a few exceptions, their relative molecular weight is relatively low. The molecular structure of epoxy resins is characterized by the presence of active epoxy groups within the molecular chain, which can be located at the end, in the middle, or in a ring structure. This active epoxy group structure allows them to cross-link with various curing agents to form insoluble, infusible polymers with a three-dimensional network structure.

[0003] Epoxy adhesives are often used in the assembly of electronic products for connection, sealing, potting, coating, and other applications. Epoxy resin, the main resin of epoxy adhesives, is mixed with appropriate amounts of curing agents, fillers, and other additives. The resulting adhesive exhibits high strength, high toughness, and rapid curing properties. It can be used to bond a variety of materials, including metals, plastics, and glass, and is widely used in the automotive, electronics, aerospace, and other fields, earning significant market recognition. However, existing epoxy adhesives still require further improvement in terms of high performance, such as low viscosity and heat resistance.

[0004] Furthermore, conventional methods for preparing trifunctional epoxy resins (e.g., CN109312052A) typically use hydrogen peroxide and peracetic acid, which are highly oxidizing and explosive when heated, as oxidants. This leads to high raw material costs, complex processes, severe environmental pollution, and low yields. Therefore, developing a low-cost, environmentally friendly, and high-yield method for preparing low-viscosity and highly heat-resistant trifunctional epoxy resin adhesives is of great practical significance. Summary of the Invention

[0005] The first object of the present invention is to provide a new trifunctional epoxy resin compound. The adhesive obtained by using the trifunctional epoxy resin compound as a base resin has low viscosity and good heat resistance.

[0006] The second object of the present invention is to provide a novel method for preparing trifunctional epoxy resin compounds, which method not only has a high total yield, but also has low cost and is more environmentally friendly.

[0007] The third object of the present invention is to provide a trifunctional epoxy resin compound prepared by the above method.

[0008] A fourth object of the present invention is to provide an epoxy adhesive containing the above-mentioned trifunctional epoxy resin compound.

[0009] Specifically, the trifunctional epoxy resin compound provided by the present invention has a structure shown in formula (1):

[0010]

[0011] In formula (1ˋ), R1, R2 and Rˋ are each independently a C1-C5 alkylene group, and R4, R5 and R6 are each independently H or a C1-C5 alkyl group.

[0012] The preparation method of the trifunctional epoxy resin compound provided by the present invention comprises the steps of subjecting an alkenylphenol to a first nucleophilic substitution reaction with a first alkene halide, subjecting the first nucleophilic substitution reaction product to a Claisen rearrangement reaction, subjecting the Claisen rearrangement reaction product to a second nucleophilic substitution reaction with a second alkene halide and / or a haloepoxypropane, and then subjecting the second nucleophilic substitution reaction product to an oxidation reaction to convert a double bond into an epoxy group, thereby obtaining the trifunctional epoxy resin compound.

[0013] The alkenylphenol has a structure represented by formula (2), the first halogenated olefin and the second halogenated olefin each independently have a structure represented by formula (3), and the halopropylene oxide has a structure represented by formula (4):

[0014]

[0015] In formula (2), R1 is a C1-C5 alkylene group, and R4, R5, and R6 are each independently H or a C1-C5 alkyl group;

[0016] In formula (3), R2 is a C1-C5 alkylene group, and X is a halogen;

[0017] In formula (4), R3 is a C1-C5 alkylene group, and X is a halogen.

[0018] The trifunctional epoxy resin compound provided by the present invention includes a benzene ring and three adjacent substituents of the benzene ring are sequentially bonded to an (alkyl) epoxy group, an (alkoxy) epoxy group / epoxy ether group and an (alkyl) epoxy group. This specific structure can give the epoxy resin adhesive a lower viscosity and good heat resistance.

[0019] In addition, the present invention uses alkenylphenol as a starting raw material. Alkenylphenol is an organic compound having an allyl group and a phenolic hydroxyl group and has active reactivity and good stability. Using alkenylphenol as a starting raw material and sequentially synthesizing a trifunctional epoxy resin through a nucleophilic substitution reaction, a Claisen rearrangement reaction, a nucleophilic substitution reaction and an oxidation reaction can ensure that the reaction activity is fully exerted and the stability of the reaction process is guaranteed, which is conducive to improving the overall yield, realizing efficient and environmentally friendly synthesis of trifunctional epoxy resin compounds, reducing production costs, having high feasibility and potential industrialization value, and laying a solid foundation for its application in the field of adhesives. DETAILED DESCRIPTION

[0020] The trifunctional epoxy resin compound provided by the present invention has a structure shown in formula (1):

[0021]

[0022] In formula (1ˋ), R1, R2, and Rˋ are each independently a C1-C5 alkylene group, preferably a C1-C3 alkylene group; R4, R5, and R6 are each independently H or a C1-C5 alkyl group, preferably H. Specific examples of the C1-C5 alkylene group include, but are not limited to, methylene, ethylene, n-propylene, isopropylene, n-butylene, sec-butylene, isobutylene, tert-butylene, n-pentylene, isopentylene, tert-pentylene, or neopentylene. Specific examples of the C1-C5 alkyl group include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, tert-pentyl, or neopentyl.

[0023] The preparation method of the trifunctional epoxy resin compound provided by the present invention comprises: performing a first nucleophilic substitution reaction on an alkenylphenol and a first halogenated olefin, performing a Claisen rearrangement reaction on the product of the first nucleophilic substitution reaction, then performing a second nucleophilic substitution reaction on the product of the Claisen rearrangement reaction with a second halogenated olefin and / or a haloepoxypropane, and then performing an oxidation reaction on the product of the second nucleophilic substitution reaction to convert a double bond into an epoxy group, thereby obtaining the trifunctional epoxy resin compound.

[0024] In the present invention, the preparation routes of the trifunctional epoxy resin compound include Route 1 and Route 2, depending on the raw materials for the second nucleophilic substitution reaction. The difference between Route 1 and Route 2 lies in the different raw materials for the second nucleophilic substitution reaction. The raw materials for the second nucleophilic substitution reaction in Route 1 are a Claisen rearrangement reaction product and a second halogenated olefin, while the raw materials for the second nucleophilic substitution reaction in Route 2 are a Claisen rearrangement reaction product and a haloepoxypropane.

[0025] The specific reaction process of route 1 is as follows:

[0026]

[0027] The specific reaction process of route 2 is as follows:

[0028]

[0029] In the present invention, the alkenylphenol has a structure shown in formula (2):

[0030]

[0031] In formula (2), R1 is a C1-C5 alkylene group, preferably a C1-C3 alkylene group; R4, R5 and R6 are each independently H or a C1-C5 alkyl group, preferably H. Specific examples of the C1-C5 alkylene group include, but are not limited to, methylene, ethylene, n-propylene, isopropylene, n-butylene, sec-butylene, isobutylene, tert-butylene, n-pentylene, isopentylene, tert-pentylene or neopentylene.

[0032] In the present invention, the first halogenated alkene and the second halogenated alkene each independently have a structure represented by formula (3):

[0033]

[0034] In formula (3), R2 is a C1-C5 alkylene group, and X is a halogen. Specific examples of the C1-C5 alkylene group include, but are not limited to, methylene, ethylene, n-propylene, isopropylene, n-butylene, sec-butylene, isobutylene, tert-butylene, n-pentylene, isopentylene, tert-pentylene, or neopentylene. The halogen includes fluorine, chlorine, or bromine. The first and second haloalkenes are particularly preferably each independently 3-bromo-1-propene and / or allyl chloride, as this makes the raw materials more reactive, thereby further improving the overall yield.

[0035] In the present invention, the haloepoxypropane has a structure shown in formula (4):

[0036]

[0037] In formula (4), R3 is a C1-C5 alkylene group, and Xˋ is a halogen. Specific examples of the C1-C5 alkylene group include, but are not limited to, methylene, ethylene, n-propylene, isopropylene, n-butylene, sec-butylene, isobutylene, tert-butylene, n-pentylene, isopentylene, tert-pentylene, or neopentylene. The halogen includes fluorine, chlorine, or bromine. The haloepoxypropane is particularly preferably epichlorohydrin and / or epibromohydrin, which further improves the overall yield.

[0038] In the present invention, the molar ratio of the alkenylphenol to the first haloalkene is preferably 1:(1-1.5), specifically 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5 or any value therebetween.

[0039] In the present invention, the molar ratio of the amount of the alkenylphenol to the total amount of the second alkylene halide and the halogenated epoxypropane is preferably 1:(1-1.5), specifically 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5 or any value therebetween.

[0040] In a preferred embodiment, the conditions of the first nucleophilic substitution reaction include a temperature of 60°C to 80°C, such as 60°C, 62°C, 64°C, 66°C, 68°C, 70°C, 72°C, 74°C, 76°C, 78°C, 80°C or any value therebetween; and a time of 1h to 10h, such as 1h, 2h, 4h, 6h, 8h, 10h or any value therebetween.

[0041] In a preferred embodiment, the conditions of the Claisen rearrangement reaction include a temperature of 180°C to 220°C, such as 180°C, 185°C, 190°C, 195°C, 200°C, 205°C, 210°C, 215°C, 220°C or any value therebetween; and a time of 1h to 96h, such as 1h, 2h, 4h, 6h, 8h, 10h, 16h, 24h, 48h, 64h, 72h, 90h, 96h or any value therebetween.

[0042] In a preferred embodiment, the conditions of the second nucleophilic substitution reaction include a temperature of 60°C to 80°C, such as 60°C, 62°C, 64°C, 66°C, 68°C, 70°C, 72°C, 74°C, 76°C, 78°C, 80°C or any value therebetween; and a time of 1h to 10h, such as 1h, 2h, 4h, 6h, 8h, 10h or any value therebetween.

[0043] In a preferred embodiment, the oxidation reaction conditions include a temperature of 0°C to 40°C, such as 0°C, 5°C, 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C or any value therebetween; and a time of 1h to 24h, such as 1h, 2h, 4h, 6h, 8h, 10h, 12h, 15h, 18h, 20h, 22h, 24h or any value therebetween.

[0044] In the present invention, the first nucleophilic substitution reaction and the second nucleophilic substitution reaction can each be independently carried out in the presence of a catalyst, which is more conducive to increasing the reaction rate. The use of the catalyst can accelerate the reaction rate and further improve the overall yield. Specific examples of the catalyst include, but are not limited to, at least one of 18-crown-6, benzyltriethylammonium chloride, tetrabutylammonium chloride, and tetrabutylammonium bromide, with 18-crown-6 being particularly preferred.

[0045] In the present invention, the first nucleophilic substitution reaction and the second nucleophilic substitution reaction are preferably carried out under alkaline conditions. The alkaline conditions are generally provided by adding an alkaline substance to the reaction system, such as at least one of potassium carbonate, sodium carbonate, potassium bicarbonate, and sodium bicarbonate. Generally, based on 1 mol of alkenylphenol, the amount of the alkaline substance used in the first nucleophilic substitution reaction and the second nucleophilic substitution reaction can be 1.1 to 1.5 mol, such as 1.1 mol, 1.2 mol, 1.3 mol, 1.4 mol, 1.5 mol, or any value therebetween.

[0046] In the present invention, the epoxidation reaction is preferably carried out in the presence of an oxidizing agent. Specific examples of the oxidizing agent include, but are not limited to, at least one of m-chloroperbenzoic acid (m-CPBA), potassium peroxymonosulfonate, hydrogen peroxide, dimethyldioxirane (DDO), and peracetic acid, with m-CPBA being particularly preferred.

[0047] In a preferred embodiment, the preparation method of the trifunctional epoxy resin compound further includes subjecting the nucleophilic substitution reaction to a first purification; and / or subjecting the second nucleophilic substitution reaction to a second purification; and / or subjecting the oxidation reaction product to a third purification. The first purification method generally comprises filtering the reaction solution, distilling the filtrate under reduced pressure to remove the solvent, washing with water, and extracting with dichloromethane, then collecting the organic phase and evaporating to dryness. The second purification method generally comprises filtering the reaction solution, distilling the filtrate under reduced pressure to remove the solvent, washing with water, and extracting with dichloromethane, then collecting the organic phase and evaporating to dryness. The third purification method generally comprises diluting the reaction solution with dichloromethane, then washing with a saturated sodium bicarbonate solution, then washing with a saturated sodium thiosulfate solution, and collecting the organic phase and evaporating to dryness.

[0048] In the present invention, the terms "first nucleophilic substitution reaction" and "second nucleophilic substitution reaction" are used solely to distinguish the nucleophilic substitution reactions occurring at two different stages for ease of description and have no other special meanings. The terms "first purification," "second purification," and "third purification" are used solely to distinguish the purification reactions occurring at two different stages for ease of description and have no other special meanings.

[0049] The present invention also provides a trifunctional epoxy resin compound prepared by the method.

[0050] The present invention also provides the use of the trifunctional epoxy resin compound as a matrix resin of an epoxy adhesive.

[0051] The present invention also provides an epoxy adhesive, wherein the epoxy adhesive matrix resin contains an epoxy resin, a thiol compound and a catalyst; the epoxy resin is the above-mentioned trifunctional epoxy resin compound.

[0052] In the present invention, the thiol compound can be any of various existing thiol group-containing compounds that can be used as epoxy resin curing agents, such as at least one of trimethylolpropane tris(3-mercaptoacetate), trimethylolpropane tris(3-mercaptopropionate), trimethylolpropane tris(3-mercaptobutyrate), pentaerythritol tetrakis(mercaptoacetate), pentaerythritol tetrakis(3-mercaptopropionate), and pentaerythritol tetrakis(3-mercaptobutyrate). Furthermore, the equivalent ratio of the epoxy group in the epoxy resin to the thiol group in the thiol compound is preferably 1:(2.5-4), such as 1:2.5, 1:3, 1:3.5, 1:4, or any value therebetween.

[0053] In the present invention, specific examples of the catalyst include, but are not limited to, at least one of an imidazole compound, an amine compound, and a phosphorus compound, preferably an imidazole compound and / or an amine compound. Specific examples include: imidazole compounds and organic acid dihydrazides that are solid at room temperature; solid-dispersed amine adducts such as the reaction products of amine compounds and epoxy compounds (amine-epoxy adducts); and reaction products of amine compounds with isocyanate compounds or urea compounds. Furthermore, the catalyst content is preferably 0.5-10% of the total content of the epoxy resin and thiol compound, such as 0.5%, 1%, 2%, 4%, 6%, 8%, 10%, or any value therebetween.

[0054] The present invention will be described in detail below through examples.

[0055] Preparation Example 1

[0056] S1. 40 g of 2-allylphenol (having the structure shown in formula (2), R1 is methylene, R4, R5 and R6 are all H, 300 mmol, 1 eq) was dissolved in 200 mL of acetone, 51.8 g (378 mmol, 1.25 eq) of potassium carbonate and 3.95 g (15 mmol, 0.05 eq) of 18-crown-6 as a phase transfer catalyst were added, the temperature was raised to 70° C. under inert gas protection, and the mixture was stirred for 10 min. Then, 20 g (330 mmol, 1.1 eq) of 3-bromo-1-propene was slowly added and the mixture was reacted for 8 h. The reaction solution was filtered, and the solvent was removed by distillation of the filtrate under reduced pressure. The filtrate was washed with water three times and extracted with dichloromethane. The organic phase was collected and evaporated to dryness to obtain a first intermediate.

[0057] S2, heating the first intermediate to 220° C. for 48 hours to obtain a second intermediate;

[0058] S3, the second intermediate was dissolved in 200 mL of acetone, 51.8 g (378 mmol, 1.25 eq) of potassium carbonate and 3.95 g (15 mmol, 0.05 eq) of 18-crown-6 as a phase transfer catalyst were added, the temperature was raised to 70° C. under inert gas protection and stirred for 10 min, and then 20 g (330 mmol, 1.1 eq) of 3-bromo-1-propene was slowly added. After reacting for 8 h, the reaction solution was filtered, the filtrate was distilled under reduced pressure to remove the solvent, the filtrate was washed three times with water, and extracted with dichloromethane. The organic phase was collected and evaporated to dryness to obtain the third intermediate;

[0059] S4. The third intermediate was dissolved in 600 mL of dichloromethane, the temperature was lowered to 0°C, 172.6 g (1.8 mol, 6 eq) of m-CPBA was slowly added, and the temperature was then raised to 40°C and the reaction was continued for 12 h. After that, dichloromethane was added to dilute the solution, and the solution was washed three times with a saturated aqueous sodium bicarbonate solution and then washed twice with a saturated sodium thiosulfate solution. The organic phase was collected and evaporated to dryness to obtain 64.8 g of the final product, a trifunctional epoxy resin compound, recorded as HS-1.

[0060] The total yield of the four-step reaction products was 83%.

[0061] The NMR data of trifunctional epoxy resin compounds are as follows: 1 H NMR (500MHz, CDCl3) δ7.29-7.18(m,2H),7.14-7.03(m,1H),4.21-4.11(m,1H),3.73(ddt,J=9.4,7.5,3. 7Hz,1H),3.40-3.34(m,1H),3.26-3.16(m,2H),3.02-2.85(m,5H),2.83-2.70(m,3H),2.66-2.54(m,2H).

[0062] Preparation Example 2

[0063] S1. 800 g of 2-allylphenol (having the structure shown in formula (2), R1 is methylene, R4, R5 and R6 are all H, 6 mol, 1 eq) was dissolved in 2 L of acetone, 1.04 kg (7.56 mol, 1.25 eq) of potassium carbonate and 79 g (300 mmol, 0.05 eq) of 18-crown-6 were added as a phase transfer catalyst, the temperature was raised to 60° C. under inert gas protection, and the mixture was stirred for 10 min. Then, 400 g (6.6 mol, 1.1 eq) of 3-bromo-1-propene was slowly added. After reacting for 10 h, the reaction solution was filtered, the filtrate was distilled under reduced pressure to remove the solvent, the filtrate was washed three times with water, and extracted with dichloromethane. The organic phase was collected and evaporated to dryness to obtain a first intermediate;

[0064] S2, heating the first intermediate to 200° C. and reacting for 48 hours to obtain a second intermediate;

[0065] S3, the second intermediate was dissolved in 2L acetone, 1.04kg (7.56mol, 1.25eq) of potassium carbonate and 79g (300mmol, 0.05eq) of phase transfer catalyst 18-crown-6 were added, the temperature was raised to 60°C under inert gas protection and stirred for 10min, and then 400g (6.6mol, 1.1eq) of 3-bromo-1-propene was slowly added. After reacting for 10h, the reaction solution was filtered, the filtrate was distilled under reduced pressure to remove the solvent, the filtrate was washed three times with water, and extracted with dichloromethane. The organic phase was collected and evaporated to dryness to obtain the third intermediate;

[0066] S4. The third intermediate was dissolved in 10 L of dichloromethane, cooled to -10 ° C, and 3.45 kg (36 mol, 6 eq) of m-CPBA was slowly added. The temperature was then raised to 10 ° C. After the reaction was continued at this temperature for 24 hours, dichloromethane was added to dilute the solution, and the solution was washed three times with a saturated aqueous sodium bicarbonate solution and then washed twice with a saturated sodium thiosulfate solution. The organic phase was collected and evaporated to dryness to obtain 1.2 kg of the final product, a trifunctional epoxy resin compound, recorded as HS-2.

[0067] The total yield of the four-step reaction products was 80%.

[0068] Preparation Example 3

[0069] S1. 4 kg of 2-allylphenol (having the structure shown in formula (2), R1 is methylene, R4, R5 and R6 are all H, 30 mol, 1 eq) was dissolved in 20 L of acetone, 5.18 kg (37.8 mol, 1.25 eq) of potassium carbonate and 395 g (1.5 mol, 0.05 eq) of 18-crown-6 as a phase transfer catalyst were added, the temperature was raised to 80° C. under inert gas protection and stirred for 10 min, and then 2 kg (33 mol, 1.1 eq) of 3-bromo-1-propene was slowly added. After reacting for 1 h, the reaction solution was filtered, the filtrate was distilled under reduced pressure to remove the solvent, the filtrate was washed with water three times, and extracted with dichloromethane. The organic phase was collected and evaporated to dryness to obtain the first intermediate;

[0070] S2, heating the first intermediate to 180° C. for 96 hours to obtain a second intermediate;

[0071] S3. The second intermediate was dissolved in 2 L of acetone, and 5.18 kg (37.8 mol, 1.25 eq) of potassium carbonate and 395 g (1.5 mol, 0.05 eq) of 18-crown-6 as a phase transfer catalyst were added. The mixture was heated to 80° C. and stirred for 10 min under inert gas protection. Then, 2 kg (33 mol, 1.1 eq) of 3-bromo-1-propene was slowly added. After reacting for 1 h, the reaction solution was filtered, and the filtrate was distilled under reduced pressure to remove the solvent. The filtrate was washed three times with water and extracted with dichloromethane. The organic phase was collected and evaporated to dryness to obtain the third intermediate.

[0072] S4. The third intermediate was dissolved in 30 L of dichloromethane, cooled to -20 ° C, and 17.3 kg (180 mol, 6 eq) of m-CPBA was slowly added. The temperature was then raised to 30 ° C. After the reaction was continued at this temperature for 24 hours, dichloromethane was added to dilute the solution, and the solution was washed three times with a saturated aqueous sodium bicarbonate solution and then washed twice with a saturated sodium thiosulfate solution. The organic phase was collected and evaporated to dryness to obtain 5.98 kg of the final product, a trifunctional epoxy resin compound, recorded as HS-3.

[0073] The total yield of the four-step reaction products was 77%.

[0074] Preparation Example 4

[0075] S1. 67 g of 2-allylphenol (having the structure shown in formula (2), R1 is methylene, R4, R5 and R6 are all H, 500 mmol, 1 eq) was dissolved in 500 mL of acetone, and 86 g of potassium carbonate (625 mmol, 1.25 eq) and 6.6 g of 18-crown-6 (25 mmol, 0.05 eq) as a phase transfer catalyst were added. The mixture was heated to 70° C. and stirred for 10 min under the protection of an inert gas. Then, 78 g of 3-bromo-1-propene (650 mmol, 1.3 eq) was slowly added. After reacting for 8 h, the reaction solution was filtered, and the solvent was distilled off under reduced pressure from the filtrate. The filtrate was washed three times with water and extracted with dichloromethane. The organic phase was collected and evaporated to dryness to obtain a first intermediate.

[0076] S2, heating the first intermediate to 220° C. for 48 hours to obtain a second intermediate;

[0077] S3, the second intermediate was dissolved in 500mL of acetone, 86g (625mmol, 1.25eq) of potassium carbonate and 8g (25mmol, 0.05eq) of catalyst tetrabutylammonium bromide were added, the temperature was raised to 70°C under inert gas protection and stirred for 10min, and then 60g (650mmol, 1.3eq) of epichlorohydrin was slowly added. After reacting for 8h, the reaction solution was filtered, and the filtrate was distilled under reduced pressure to remove the solvent, washed three times with water, and extracted with dichloromethane. The organic phase was collected and evaporated to dryness to obtain a third intermediate;

[0078] S4. The third intermediate product was dissolved in 1 L of dichloromethane, the temperature was raised to 40 ° C, 350 g of m-CPBA (2 mol, 4 eq) was slowly added, and after reacting for 12 h, dichloromethane was added to dilute the solution, and the solution was washed three times with a saturated aqueous sodium bicarbonate solution and then washed twice with a saturated sodium thiosulfate solution. The organic phase was collected and evaporated to dryness to obtain 87.7 g of the final product, a trifunctional epoxy resin compound, recorded as HS-4.

[0079] The total yield of the four-step reaction products was 67%.

[0080] The NMR data of trifunctional epoxy resin compounds are as follows: 1 H NMR (500MHz, CDCl3) δ7.29-7.18(m,2H),7.14-7.03(m,1H),4.21-4.11(m,1H),3.73(ddt,J=9.4,7.5,3. 7Hz,1H),3.40-3.34(m,1H),3.26-3.16(m,2H),3.02-2.85(m,5H),2.83-2.70(m,3H),2.66-2.54(m,2H).

[0081] Preparation Example 5

[0082] S1. 335 g of 2-allylphenol (having the structure shown in formula (2), R1 is methylene, R4, R5 and R6 are all H, 2.5 mol, 1 eq) was dissolved in 2.5 L of acetone, 430 g of potassium carbonate (3.125 mol, 1.25 eq) and 33 g of 18-crown-6 (125 mmol, 0.05 eq) as a phase transfer catalyst were added, the temperature was raised to 70° C. under inert gas protection, and the mixture was stirred for 10 min. Then, 390 g of 3-bromo-1-propene (3.25 mol, 1.3 eq) was slowly added. After reacting for 8 h, the reaction solution was filtered, the filtrate was distilled under reduced pressure to remove the solvent, the filtrate was washed three times with water, and extracted with dichloromethane. The organic phase was collected and evaporated to dryness to obtain the first intermediate;

[0083] S2, heating the first intermediate to 220° C. for 48 hours to obtain a second intermediate;

[0084] S3, the second intermediate was dissolved in 2.5L ethanol, 125g (3.125mol, 1.25eq) of sodium hydroxide was added, the temperature was raised to 60°C under inert gas protection and stirred for 10min, and then 300g (3.25mol, 1.3eq) of epichlorohydrin was slowly added. After reacting for 2h, the pH of the reaction solution was adjusted to neutral with saturated sodium bicarbonate solution, washed three times with water, and extracted with dichloromethane. The organic phase was collected and evaporated to dryness to obtain a third intermediate;

[0085] S4. The third intermediate was dissolved in dichloromethane, the temperature was raised to 40°C, 1.75 kg (10 mol, 4 eq) of m-CPBA was slowly added, and the reaction was continued for 12 h. Then, dichloromethane was added to dilute the solution, and the solution was washed three times with a saturated aqueous sodium bicarbonate solution and then washed twice with a saturated aqueous sodium thiosulfate solution. The organic phase was collected and evaporated to dryness to obtain 418.8 g of the final product, a trifunctional epoxy resin compound, which was recorded as HS-5.

[0086] The total yield of the four-step reaction products was 64%.

[0087] Preparation Example 6

[0088] S1. 3.35 kg of 2-allylphenol (having the structure shown in formula (2), R1 is methylene, R4, R5 and R6 are all H, 25 mol, 1 eq) was dissolved in 25 L of acetone, 4.3 kg of potassium carbonate (31.25 mol, 1.25 eq) and 330 g of 18-crown-6 (1.25 mol, 0.05 eq) as a phase transfer catalyst were added, the temperature was raised to 70° C. under inert gas protection, and stirred for 10 min. Then, 3.9 kg of 3-bromo-1-propene (32.5 mol, 1.3 eq) was slowly added. After reacting for 8 h, the reaction solution was filtered, the filtrate was distilled under reduced pressure to remove the solvent, the filtrate was washed three times with water, and extracted with dichloromethane. The organic phase was collected and evaporated to dryness to obtain a first intermediate product;

[0089] S2, heating the first intermediate to 220° C. for 48 hours to obtain a second intermediate;

[0090] S3, the second intermediate was dissolved in 25L acetonitrile, 4.3kg (31.25mol, 1.25eq) of potassium carbonate was added, the temperature was raised to 80°C under inert gas protection and stirred for 10min, and then 3kg (32.5mol, 1.3eq) of epichlorohydrin was slowly added. After the reaction was carried out for 8h, the reaction solution was filtered, the filtrate was distilled under reduced pressure to remove the solvent, the filtrate was washed three times with water, and extracted with dichloromethane. The organic phase was collected and evaporated to dryness to obtain a third intermediate;

[0091] S4. The third intermediate was dissolved in 50 L of dichloromethane, the temperature was raised to 40 ° C, 17.5 kg (100 mol, 4 eq) of m-CPBA was slowly added, and after reacting for 12 h, dichloromethane was added to dilute the solution, and the solution was washed three times with a saturated aqueous sodium bicarbonate solution and then washed twice with a saturated aqueous sodium thiosulfate solution. The organic phase was collected and evaporated to dryness to obtain 4 kg of the final product, a trifunctional epoxy resin compound, recorded as HS-6.

[0092] The total yield of the four-step reaction products was 61%.

[0093] Example 1

[0094] A trifunctional epoxy resin compound (HS-1), trimethylolpropane tris(3-mercaptopropionate) and a catalyst (imidazole compound, purchased from Ajinomoto Co., Ltd., brand PN23) were stirred uniformly at a rotation speed of 2000 rpm, wherein the equivalent ratio of epoxy groups in the trifunctional epoxy resin compound to mercapto groups in trimethylolpropane tris(3-mercaptopropionate) was 1:1, and the amount of the catalyst was 2% of the total content of the epoxy resin and the thiol compound to obtain an epoxy adhesive.

[0095] Example 2

[0096] A trifunctional epoxy resin compound (HS-2), trimethylolpropane tris(3-mercaptobutyrate) and a catalyst (imidazole compound, purchased from Ajinomoto Co., Ltd., brand PN23) were stirred uniformly at a rotation speed of 2000 rpm, wherein the equivalent ratio of the epoxy group in the trifunctional epoxy resin compound to the thiol group in trimethylolpropane tris(3-mercaptobutyrate) was 1:1, and the amount of the catalyst was 0.5% of the total content of the epoxy resin and the thiol compound to obtain an epoxy adhesive.

[0097] Example 3

[0098] A trifunctional epoxy resin compound (HS-3), trimethylolpropane tris(3-mercaptopropionate) and a catalyst (imidazole compound, purchased from Ajinomoto Co., Ltd., brand PN23) were stirred uniformly at a rotation speed of 2000 rpm, wherein the equivalent ratio of the epoxy group in the trifunctional epoxy resin compound to the mercapto group in trimethylolpropane tris(3-mercaptopropionate) was 1:1, and the amount of the catalyst was 5% of the total content of the epoxy resin and the thiol compound to obtain an epoxy adhesive.

[0099] Example 4

[0100] A trifunctional epoxy resin compound (HS-4), trimethylolpropane tris(3-mercaptopropionate) and a catalyst (imidazole compound, purchased from Ajinomoto Co., Ltd., brand PN23) were stirred uniformly at a rotation speed of 2000 rpm, wherein the equivalent ratio of the epoxy group in the trifunctional epoxy resin compound to the mercapto group in trimethylolpropane tris(3-mercaptopropionate) was 1:1.5, and the amount of the catalyst was 2% of the total content of the epoxy resin and the thiol compound to obtain an epoxy adhesive.

[0101] Example 5

[0102] A trifunctional epoxy resin compound (HS-5), trimethylolpropane tris(3-mercaptopropionate) and a catalyst (imidazole compound, purchased from Ajinomoto Co., Ltd., brand PN23) were stirred uniformly at a rotation speed of 2000 rpm, wherein the equivalent ratio of the epoxy group in the trifunctional epoxy resin compound to the mercapto group in trimethylolpropane tris(3-mercaptopropionate) was 1:2, and the amount of the catalyst was 2% of the total content of the epoxy resin and the thiol compound to obtain an epoxy adhesive.

[0103] Example 6

[0104] A trifunctional epoxy resin compound (HS-6), trimethylolpropane tris(3-mercaptopropionate) and a catalyst (imidazole compound, purchased from Ajinomoto Co., Ltd., brand PN23) were stirred uniformly at a rotation speed of 2000 rpm, wherein the equivalent ratio of the epoxy group in the trifunctional epoxy resin compound to the mercapto group in trimethylolpropane tris(3-mercaptopropionate) was 1:3, and the amount of the catalyst was 2% of the total content of the epoxy resin and the thiol compound to obtain an epoxy adhesive.

[0105] Comparative Example 1

[0106] An epoxy adhesive was prepared according to the method of Example 1, except that the trifunctional epoxy resin compound (HS-1) was replaced by the same weight portion of an N-containing epoxy resin (aliphatic glycidyl ether having the structure shown in formula (5)), and the amount of the curing agent was adjusted so that the thiol and epoxy equivalent ratio in the system was the same as that in Example 1. The remaining conditions were the same as those in Example 1 to obtain an epoxy adhesive.

[0107]

[0108] Test Case

[0109] (1) Bond Strength: The epoxy adhesives obtained in each Example and Comparative Example were coated on stainless steel sheets and pressed together with the stainless steel. 0.1 mm copper wire was used to control the adhesive layer thickness. The adhesive layer area was 25.4 mm × 5 mm. The samples were heated to 45°C and cured for 60 min. The two sheets were then pulled apart in opposite directions using a universal testing machine. The measured force was the initial bond strength. The results are shown in Table 1.

[0110] The epoxy adhesives obtained in each example and comparative example were coated onto stainless steel sheets and pressed together using stainless steel. A 0.1 mm copper wire was used to control the adhesive layer thickness, resulting in an adhesive layer area of ​​25.4 mm x 5 mm. The samples were heated to 45°C and cured for 60 minutes. The cured samples were then heated at 85°C for 120 hours. The shear bond strength of the samples was then tested at an ambient temperature of 85°C. The measured force value is the thermal bond strength. The results are shown in Table 1.

[0111] (2) Viscosity: The epoxy adhesives obtained in each embodiment and comparative example were tested using a HAAKE rheometer, using a cone-plate viscometer with a 40 mm rotor, a test temperature of 25° C., and a rotation speed of 40 s. -1 The average value of the three sets of parallel data was taken as the final viscosity. The results are shown in Table 1.

[0112] Table 1

[0113] project Initial bonding strength (MPa) Thermal bonding strength (MPa) Viscosity (mPa·s) Example 1 5736 5521 91.6 Example 2 5821 5673 93.2 Example 3 5826 5686 93.8 Example 4 5836 8762 95.4 Example 5 5785 5548 96.7 Example 6 5614 5314 97.8 Comparative Example 1 6012 4211 86.3

[0114] It can be seen from the results of the above examples and comparative examples that the trifunctional epoxy resin compound provided by the present invention can impart lower viscosity and good heat resistance to the epoxy adhesive.

[0115] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and purpose of the present invention.

Claims

1. A trifunctional epoxy resin compound, characterized in that: The trifunctional epoxy resin compound has a structure shown in formula (1): In formula (1ˋ), R1, R2 and Rˋ are each independently a C1-C5 alkylene group, and R4, R5 and R6 are each independently H or a C1-C5 alkyl group.

2. The trifunctional epoxy resin compound according to claim 1, characterized in that: In formula (1ˋ), R1, R2 and Rˋ are each independently a C1-C3 alkylene group, and R4, R5 and R6 are H.

3. A method for preparing a trifunctional epoxy resin compound, characterized in that: The method comprises subjecting an alkenyl phenol to a first nucleophilic substitution reaction with a first olefin halide, subjecting the first nucleophilic substitution reaction product to a Claisen rearrangement reaction, subjecting the Claisen rearrangement reaction product to a second nucleophilic substitution reaction with a second olefin halide and / or a haloepoxypropane, and subjecting the second nucleophilic substitution reaction product to an oxidation reaction so that a double bond is converted into an epoxy group, thereby obtaining a trifunctional epoxy resin compound; The alkenylphenol has a structure shown in formula (2), the first olefin halide and the second olefin halide each independently have a structure shown in formula (3), and the halogenated propylene oxide has a structure shown in formula (4): In formula (2), R1 is a C1-C5 alkylene group, and R4, R5 and R6 are each independently H or a C1-C5 alkyl group; In formula (3), R2 is a C1-C5 alkylene group, and X is a halogen; In formula (4), R3 is a C1-C5 alkylene group, and X is a halogen.

4. The method for preparing a trifunctional epoxy resin compound according to claim 3, characterized in that: The molar ratio of the amount of the alkenylphenol to the amount of the first halogenated olefin is 1:(1-1.5); the molar ratio of the amount of the alkenylphenol to the total amount of the second halogenated olefin and the halogenated propylene oxide is 1:(1-1.5).

5. The method for preparing a trifunctional epoxy resin compound according to claim 3, characterized in that: The first olefin halide and the second olefin halide are each independently 3-bromo-1-propene and / or allyl chloride; the halogenated epoxypropane is epichlorohydrin and / or epibromohydrin.

6. The method for preparing a trifunctional epoxy resin compound according to claim 3, characterized in that: The conditions of the first nucleophilic substitution reaction include a temperature of 60°C to 80°C and a time of 1h to 10h; Preferably, the conditions of the Claisen rearrangement reaction include a temperature of 180°C to 220°C and a time of 1h to 96h; Preferably, the conditions of the second nucleophilic substitution reaction include a temperature of 60°C to 80°C and a time of 1h to 10h; Preferably, the oxidation reaction conditions include a temperature of 0°C to 40°C and a time of 1h to 24h.

7. The method for preparing a trifunctional epoxy resin compound according to claim 3, characterized in that: The first nucleophilic substitution reaction and the second nucleophilic substitution reaction are each independently performed in the presence of a catalyst, and the catalyst is 18-crown ether-6.

8. The method for preparing a trifunctional epoxy resin compound according to claim 3, characterized in that: The epoxidation reaction is carried out in the presence of an oxidant, which is m-CPBA.

9. A trifunctional epoxy resin compound prepared by the method according to any one of claims 3 to 8.

10. Use of the trifunctional epoxy resin compound according to claim 1, 2 or 9 as a base resin for epoxy adhesive.

11. An epoxy adhesive, characterized in that: The epoxy adhesive matrix resin contains epoxy resin, thiol compound and catalyst; the epoxy resin is the trifunctional epoxy resin compound according to claim 1, 2 or 9.

12. The epoxy adhesive according to claim 11, characterized in that The thiol compound is at least one selected from trimethylolpropane tris(3-mercaptoacetate), trimethylolpropane tris(3-mercaptopropionate), trimethylolpropane tris(3-mercaptobutyrate), pentaerythritol tetrakis(mercaptoacetate), pentaerythritol tetrakis(3-mercaptopropionate) and pentaerythritol tetrakis(3-mercaptobutyrate).

13. The epoxy adhesive according to claim 11, characterized in that: The equivalent ratio of the epoxy group in the epoxy resin to the mercapto group in the thiol compound is 1:(2.5-4).

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