High-heat-resistant and high-adhesion single-component epoxy adhesive, preparation method and application thereof

Abstract

The application belongs to the field of adhesives and sealants, and relates to a single-component epoxy adhesive with high heat resistance and high adhesion as well as a preparation method and application thereof. The single-component epoxy adhesive contains a first epoxy resin, a second epoxy resin, a curing agent, an accelerator, a filler, a coupling agent and optional auxiliaries; the first epoxy resin is a combination of bisphenol A type epoxy resin and alicyclic epoxy resin; and the second epoxy resin is bisphenol F type four-membered ring epoxy resin. The bisphenol A diglycidyl ether and low-viscosity alicyclic epoxy resin are used as the first epoxy resin, and the bisphenol F type four-membered ring epoxy resin with a specific structure is used as the second epoxy resin, so that the curing degree of the epoxy adhesive can be perfectly improved, the heat resistance is improved while the high Tg and high adhesion strength are ensured, and the epoxy adhesive with high adhesion strength and heat resistance is particularly suitable for applications in the field of electronic packaging and the like.

Description

Technical Field

[0001] This invention belongs to the field of adhesives and sealants, and specifically relates to a high heat-resistant and high-adhesion single-component epoxy adhesive, its preparation method, and its application. Background Technology

[0002] Epoxy resins are widely used in coatings, adhesives, composite materials, and electronic packaging materials due to their excellent mechanical properties, superior processing performance, low curing shrinkage, and good resistance to chemical solvents. Epoxy adhesives, in particular, fill surface irregularities and form strong bonds, while also possessing advantages such as shear and peel resistance, high bond strength, no excess byproducts, and low shrinkage. These characteristics have made them a hot topic and focus of research in the epoxy resin industry.

[0003] 50% of electronic device failures are caused by adhesive failure. Glass transition temperature (Tg) and bond strength are crucial indicators for evaluating adhesive performance. Tg is the temperature at which a material transitions from rigid to flexible, directly affecting its mechanical properties such as flexural strength, tensile strength, and toughness. Below Tg, the material exhibits glassy brittleness, while above Tg, it possesses better elasticity and plasticity. Below Tg, the movement between material molecules slows down, resulting in better thermal stability. Tg also influences the material's high-temperature resistance and thermal deformation behavior. However, existing epoxy adhesives typically use low-functionality epoxy resins as the main component, resulting in generally lower Tg values. Furthermore, bond strength directly determines the overall strength of the bonded structure. Insufficient bond strength can lead to failure modes such as shearing, peeling, or fracture at the bond interface, causing structural damage. Bond strength is also closely related to the durability of the bonded component. Low bond strength can cause the interface to loosen, slip, or crack, leading to failure during use. Higher bond strength provides better resistance to fatigue, aging, and environmental degradation, resulting in a longer service life for bonded components. However, epoxy adhesives can be affected by external environmental factors such as ultraviolet radiation, heat, humidity, and chemicals, causing changes in the molecular structure of the epoxy resin. This leads to poor heat resistance, making the adhesive more prone to failure and affecting its bonding performance after exposure to high temperatures, thus requiring additional protective measures or regular maintenance. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing epoxy adhesives, such as low Tg, low bonding strength, or poor heat resistance, and to provide a one-component epoxy adhesive with high Tg, bonding strength, and heat resistance, as well as its preparation method and application.

[0005] The single-component epoxy adhesive provided by this invention contains a first epoxy resin, a second epoxy resin, a curing agent, an accelerator, a filler, a coupling agent, and optional additives; the first epoxy resin is a composition of bisphenol A type epoxy resin and an alicyclic epoxy resin; the second epoxy resin is a bisphenol F type tetrafunctional epoxy resin having the structure shown in formula (I).

[0006]

[0007] In formula (Ⅰ), R1 and R2 are each independently a C1 to C5 alkyl group.

[0008] In a preferred embodiment, the content of the first epoxy resin is 30-50 parts by weight, the content of the second epoxy resin is 30-50 parts by weight, the content of the curing agent is 3-15 parts by weight, the content of the accelerator is 0.1-10 parts by weight, the content of the filler is 2-60 parts by weight, the content of the coupling agent is 0.1-2 parts by weight, and the content of the additive is 0.1-10 parts by weight.

[0009] In a preferred embodiment, the weight ratio of the first epoxy resin to the second epoxy resin is 1:(0.5-2).

[0010] In a preferred embodiment, the weight ratio of bisphenol A epoxy resin to alicyclic epoxy resin in the first epoxy resin is 1:(0.1 to 0.5).

[0011] In a preferred embodiment, the bisphenol F type tetrafunctional epoxy resin is prepared by a method comprising the following steps:

[0012] (1) 4-allyl-2-alkoxyphenol with the structure shown in formula (II) and formaldehyde are subjected to an addition reaction in the presence of a first alkaline medium and water. The resulting addition reaction product is then subjected to a condensation reaction with 4-allyl-2-alkoxyphenol in the presence of a second alkaline medium and an organic solvent and purified to obtain the first intermediate product.

[0013] (2) The first intermediate product was subjected to a substitution reaction with an allyl halide compound having the structure shown in formula (III) in the presence of a phase transfer catalyst and a third alkaline medium, and then purified to obtain the second intermediate product.

[0014] (3) The second intermediate product was oxidized in the presence of an oxidant and then purified to obtain bisphenol F type tetrafunctional epoxy resin.

[0015]

[0016] In formula (II), R3 is a C1 to C5 alkyl group;

[0017] In equation (Ⅲ), X is a halogen atom.

[0018] In a preferred embodiment, in step (1), the molar ratio of 4-allyl-2-alkoxyphenol to formaldehyde used in the addition reaction is (0.5-2):1.

[0019] In a preferred embodiment, in step (1), the molar ratio of 4-allyl-2-alkoxyphenol used in the condensation reaction to that used in the addition reaction is (0.9-1.1):1.

[0020] In a preferred embodiment, in step (1), the first alkaline medium and the second alkaline medium are each independently selected from at least one of potassium hydroxide, sodium hydroxide, magnesium hydroxide, calcium hydroxide, barium hydroxide, sodium carbonate and potassium carbonate.

[0021] In a preferred embodiment, in step (1), the conditions for the addition reaction include a temperature of 30–50°C and a time of 5–20 h.

[0022] In a preferred embodiment, in step (1), the conditions for the condensation reaction include a temperature of 60–100°C and a time of 48–100 h.

[0023] In a preferred embodiment, in step (2), the molar ratio of the amount of the allyl halogenated compound used to the total amount of 4-allyl-2-alkoxyphenol used in the addition reaction and the condensation reaction is (1.5-2.5):1.

[0024] In a preferred embodiment, in step (2), the allyl halogenated compound is allyl bromide and / or allyl chloride.

[0025] In a preferred embodiment, in step (2), the phase transfer catalyst is selected from at least one of cyclic crown ethers, polyethers, and ammonium compounds.

[0026] In a preferred embodiment, in step (2), the third alkaline medium is selected from at least one of potassium hydroxide, sodium hydroxide, magnesium hydroxide, calcium hydroxide, barium hydroxide, sodium carbonate, and potassium carbonate.

[0027] In a preferred embodiment, in step (2), the conditions for the substitution reaction include a temperature of 60–80°C and a time of 4–12 h.

[0028] In a preferred embodiment, in step (3), the oxidant is a peroxide and / or hydrogen peroxide.

[0029] In a preferred embodiment, in step (3), the oxidation reaction conditions include a temperature of 20–60°C and a time of 24–96 hours.

[0030] In a preferred embodiment, the curing agent is selected from at least one of amine curing agents, acid anhydride curing agents, phenolic curing agents, imidazole curing agents, and latent curing agents.

[0031] In a preferred embodiment, the accelerator is selected from at least one of imidazole-based curing accelerators, tertiary amine-based curing accelerators, substituted urea-based curing accelerators, phosphorus compound-based curing accelerators, and microencapsulated curing accelerators.

[0032] In a preferred embodiment, the filler is selected from at least one of carbon black, silica, alumina, talc, calcium carbonate, glass microspheres, metal powder, and polytetrafluoroethylene filler.

[0033] In a preferred embodiment, the coupling agent is selected from at least one of γ-methacryloxypropyltrimethoxysilane, vinyltri(β-methoxyethoxy)silane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, anilinemethyltriethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and γ-ureapropyltriethoxysilane.

[0034] In a preferred embodiment, the additive is selected from at least one of stabilizers, polymerization inhibitors, antioxidants, flame retardants, diluents, adhesion promoters, dyes, pigments, defoamers, leveling agents, homogenizers, and ion trapping agents.

[0035] The method for preparing the one-component epoxy adhesive provided by the present invention includes: mixing a first epoxy resin, a second epoxy resin, a curing agent, an accelerator, a filler, a coupling agent, and optional additives evenly to obtain the one-component epoxy adhesive.

[0036] Furthermore, the present invention also provides the application of the single-component epoxy adhesive as an adhesive or sealant.

[0037] The key to this invention lies in using bisphenol A diglycidyl ether and a low-viscosity alicyclic epoxy resin as the first epoxy resin, and bisphenol F tetrafunctional epoxy resin with a specific structure as the second epoxy resin. This can perfectly improve the curing degree of the epoxy adhesive, and improve heat resistance while ensuring high Tg and high bonding strength. This epoxy adhesive with both high bonding strength and heat resistance is particularly suitable for applications in fields such as electronic packaging. Attached Figure Description

[0038] Figure 1 The bisphenol F type tetrafunctional epoxy resin obtained in Example 1 1 H-NMR spectrum.

[0039] Figure 2 The bisphenol F type tetrafunctional epoxy resin obtained in Example 1 13 C-NMR spectrum. Detailed Implementation

[0040] The single-component epoxy adhesive provided by this invention contains a first epoxy resin, a second epoxy resin, a curing agent, an accelerator, a filler, and a coupling agent, and may further contain additives. Preferably, the content of the first epoxy resin is 30-50 parts by weight, such as 30, 32, 35, 38, 40, 42, 45, 48, 50 parts by weight or any value between them; the content of the second epoxy resin is preferably 30-50 parts by weight, such as 30, 32, 35, 38, 40, 42, 45, 48, 50 parts by weight or any value between them; the content of the curing agent is preferably 3-15 parts by weight, such as 3, 5, 8, 10, 12, 15 parts by weight or any value between them; the content of the accelerator is preferably 0.1-10 parts by weight. The content of the filler is preferably 2 to 60 parts by weight, such as 2, 5, 8, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60 parts by weight or any value between them; the content of the coupling agent is preferably 0.1 to 2 parts by weight, such as 0.1, 0.5, 1, 1.5, 2 parts by weight or any value between them; the content of the auxiliary agent is preferably 0.1 to 10 parts by weight, such as 0.1, 1, 2, 5, 8, 10 parts by weight or any value between them.

[0041] In this invention, the weight ratio of the first epoxy resin to the second epoxy resin is preferably 1:(0.5-2), such as 1:0.5, 1:0.8, 1:1, 1:1.2, 1:1.5, 1:2 or any value between them. In this case, the resulting single-component epoxy adhesive not only has good bonding strength, but also achieves a high crosslinking density, improving Tg, heat resistance, mechanical properties and flame retardancy, while also having a suitable viscosity to ensure construction performance.

[0042] In this invention, the first epoxy resin is a composition of bisphenol A type epoxy resin and alicyclic epoxy resin. Preferably, the weight ratio of bisphenol A type epoxy resin to alicyclic epoxy resin in the first epoxy resin is 1:(0.1-0.5), such as 1:0.1, 1:0.2, 1:0.3, 1:0.4, 1:0.5, or any value between them. In this case, the resulting one-component epoxy adhesive can reduce viscosity and curing shrinkage while improving weather resistance, while ensuring cost control.

[0043] Specific examples of the alicyclic epoxy resins include, but are not limited to: cyclohexene oxide, oxetane, cyclohexane-type diglycidyl ether, cyclohexene-type diglycidyl ether, dicyclopentadiene-type diglycidyl ether, etc., such as 3,4-epoxycyclohexylcarboxylic acid-3',4'-epoxycyclohexylmethyl ester, 3,4-epoxycyclohexyl-6-methylcarboxylic acid-3',4'-epoxycyclohexyl-6'-methyl ester, bis((3,4-epoxycyclohexyl)methyl)adipate, 1,4-cyclohexanediethanol bis(3,4-epoxycyclohexanecarboxylic acid) ester, and dioxide. At least one of the following: dicyclopentadiene, bis(2,3-epoxycyclopentyl) ether, 4-vinyl-1-cyclohexene diepoxide, 7,7'-dioxa-3,3'-bis[bicyclo[4.1.0]heptane], 3,3'-(oxydimethylene)bis(3-ethyl)oxacyclobutane, cyclohexanediethanol diglycidyl ether, vinyl(3,4-cyclohexene)dioxide, 2-(3,4-epoxycyclohexyl)-5,1-spiro-(3,4-epoxycyclohexyl)m-dioxane, and 1,4-bis[(glycidoxy)methyl]cyclohexane. Furthermore, the epoxy equivalent of the bisphenol A type epoxy resin and the alicyclic epoxy resin is preferably 80-600 g / eq each, more preferably 90-450 g / eq, such as 90, 100, 120, 150, 180, 200, 220, 250, 280, 300, 320, 350, 380, 400, 420, 450 g / eq.

[0044] In this invention, the second epoxy resin is a bisphenol F type tetrafunctional epoxy resin having the structure shown in formula (I):

[0045]

[0046] In formula (I), R1 and R2 are each independently a C1 to C5 alkyl group. Specific examples of the C1 to C5 alkyl groups 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.

[0047] In this invention, the bisphenol F type tetrafunctional epoxy resin can be commercially available or prepared according to various methods known in the art. In a preferred embodiment, the bisphenol F type tetrafunctional epoxy resin is prepared according to a method comprising the following steps:

[0048] (1) 4-allyl-2-alkoxyphenol with the structure shown in formula (II) and formaldehyde are subjected to an addition reaction in the presence of a first alkaline medium and water. The resulting addition reaction product is then subjected to a condensation reaction with 4-allyl-2-alkoxyphenol in the presence of a second alkaline medium and an organic solvent and purified to obtain the first intermediate product.

[0049] (2) The first intermediate product was subjected to a substitution reaction with an allyl halide compound having the structure shown in formula (III) in the presence of a phase transfer catalyst and a third alkaline medium, and then purified to obtain the second intermediate product.

[0050] (3) The second intermediate product was oxidized in the presence of an oxidant and then purified to obtain bisphenol F type tetrafunctional epoxy resin.

[0051]

[0052] In formula (II), R3 is a C1 to C5 alkyl group;

[0053] In equation (Ⅲ), X is a halogen atom.

[0054] In the preparation process of the above-mentioned bisphenol F type tetrafunctional epoxy resin, in step (1), the molar ratio of 4-allyl-2-alkoxyphenol to formaldehyde used in the addition reaction is preferably (0.5~2):1, such as 0.5:1, 0.8:1, 1:1, 1.2:1, 1.5:1, 1.8:1, 2:1 or any value between them.

[0055] In the preparation process of the above-mentioned bisphenol F type tetrafunctional epoxy resin, in step (1), the ratio of water to 4-allyl-2-alkoxyphenol used in the addition reaction is (4.5~10) mL:1g, such as 4.5mL:1g, 5mL:1g, 5.5mL:1g, 6mL:1g, 7mL:1g, 8mL:1g, 9mL:1g, 10mL:1g or any value between them.

[0056] In the preparation process of the above-mentioned bisphenol F type tetrafunctional epoxy resin, in step (1), the molar ratio of 4-allyl-2-alkoxyphenol used in the condensation reaction to 4-allyl-2-alkoxyphenol used in the addition reaction is (0.9~1.1):1, such as 0.9:1, 1.0:1, 1.1:1 or any value between them.

[0057] In the preparation process of the above-mentioned bisphenol F type tetrafunctional epoxy resin, in step (1), the ratio of the organic solvent to 4-allyl-2-alkoxyphenol used in the condensation reaction is (4.5-10) mL:1g, such as 4.5 mL:1g, 5 mL:1g, 5.5 mL:1g, 6 mL:1g, 7 mL:1g, 8 mL:1g, 9 mL:1g, 10 mL:1g, or any value between them. Furthermore, the organic solvent is particularly preferably dioxane.

[0058] In the preparation process of the above-mentioned bisphenol F type tetrafunctional epoxy resin, in step (1), the conditions of the addition reaction include a temperature preferably of 30 to 50°C, such as 30°C, 35°C, 38°C, 40°C, 42°C, 45°C or any value between them; and a time preferably of 5 to 20 h, such as 5 h, 8 h, 10 h, 11 h, 12 h, 15 h, 18 h, 20 h or any value between them.

[0059] In the preparation process of the above-mentioned bisphenol F type tetrafunctional epoxy resin, in step (1), the conditions of the condensation reaction include a temperature preferably of 60 to 100°C, such as 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C or any value between them; and a time preferably of 48 to 100 h, such as 48 h, 50 h, 55 h, 60 h, 65 h, 68 h, 72 h, 75 h, 80 h, 84 h, 90 h, 96 h, 100 h or any value between them.

[0060] In the preparation process of the above-mentioned bisphenol F type tetrafunctional epoxy resin, in step (1), the addition reaction and condensation reaction are preferably carried out in the following manner: add a first alkaline medium and water to 4-allyl-2-methoxyphenol, stir at a temperature of 30-50°C for 20-60 min, then slowly add 37% formaldehyde aqueous solution dropwise. After the dropwise addition is completed, continue the reaction under the same conditions for 5-20 h, then add an equal amount of 4-allyl-2-methoxyphenol and a second alkaline medium, add an organic solvent with an equal volume of water, adjust the temperature to 60-100°C and stir the reaction for 48-100 h, cool to room temperature, adjust the system to be neutral or weakly acidic with acid, and remove the liquid by rotary evaporation.

[0061] In the preparation process of the above-mentioned bisphenol F type tetrafunctional epoxy resin, in step (1), the purification method can be to first extract the obtained product with ethyl acetate as an extractant to extract the target product (organic matter) in the product into the extractant to obtain the extract phase, and then wash the extract phase with water 1 to 3 times.

[0062] In the preparation process of the above-mentioned bisphenol F type tetrafunctional epoxy resin, in step (2), the molar ratio of the amount of the allyl halogenated compound to the total amount of 4-allyl-2-alkoxyphenol used in the addition reaction and the 4-allyl-2-alkoxyphenol used in the condensation reaction is (1.5~2.5):1, such as 1.5:1, 1.8:1, 2:1, 2.2:1, 2.5:1 or any value between them.

[0063] In the preparation process of the above-mentioned bisphenol F type tetrafunctional epoxy resin, in step (2), the 4-allyl-2-alkoxyphenol has the structure shown in formula (II), wherein R3 is a C1-C5 alkyl group. 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. Specifically, the 4-allyl-2-alkoxyphenol is preferably selected from at least one of 4-allyl-2-methoxyphenol, 4-allyl-2-ethoxyphenol, 4-allyl-2-propoxyphenol, 4-allyl-2-butoxyphenol, and 4-allyl-2-pentoxyphenol.

[0064] In the preparation process of the above-mentioned bisphenol F type tetrafunctional epoxy resin, in step (2), the allyl halogenated compound has the structure shown in formula (III), wherein X is a halogen atom, such as bromine or chlorine. Accordingly, the allyl halogenated compound is preferably allyl bromine and / or allyl chloride.

[0065] In the preparation process of the above-mentioned bisphenol F type tetrafunctional epoxy resin, specific examples of the phase transfer catalyst in step (2) include, but are not limited to, at least one of cyclic crown ethers, polyethers and ammonium compounds, such as at least one of 18-crown ether-6, dibenzo-18-crown ether-6, 15-crown ether-5, etc.

[0066] In the preparation process of the above-mentioned bisphenol F type tetrafunctional epoxy resin, in step (2), the purification method can be to first extract the obtained product with ethyl acetate as an extractant to extract the target product (organic matter) in the product into the extractant to obtain the extract phase, and then wash the extract phase with water 1 to 3 times.

[0067] In the preparation process of the above-mentioned bisphenol F type tetrafunctional epoxy resin, the first alkaline medium, the second alkaline medium, and the third alkaline medium can be the same or different, as long as they can provide an alkaline environment for the reaction process. Specifically, they can each be independently selected from at least one of potassium hydroxide, sodium hydroxide, magnesium hydroxide, calcium hydroxide, barium hydroxide, sodium carbonate, and potassium carbonate. The terms "first," "second," and "third" are only for ease of distinction and description and have no other special meaning.

[0068] In the preparation process of the above-mentioned bisphenol F type tetrafunctional epoxy resin, in step (3), the conditions of the substitution reaction include a temperature preferably of 60 to 80°C, such as 60°C, 65°C, 70°C, 75°C, 80°C or any value between them; and a time preferably of 4 to 12 hours, such as 4 hours, 6 hours, 8 hours, 10 hours, 12 hours or any value between them.

[0069] In the preparation process of the above-mentioned bisphenol F type tetrafunctional epoxy resin, in step (3), the oxidant can be any existing substance capable of oxidizing the double bond in the second intermediate product to an epoxy group, preferably a peroxide and / or hydrogen peroxide. Specific examples of the peroxide include, but are not limited to, at least one of: m-chloroperoxybenzoic acid, allyl chloride, peracetic acid, etc.

[0070] In the preparation process of the above-mentioned bisphenol F type tetrafunctional epoxy resin, in step (3), the conditions of the oxidation reaction include a temperature preferably of 20 to 60°C, such as 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C or any value between them; and a time preferably of 24 to 96 hours, such as 24h, 30h, 35h, 40h, 48h, 50h, 55h, 60h, 65h, 68h, 72h, 75h, 80h, 84h, 90h, 96h or any value between them.

[0071] In the preparation process of the above-mentioned bisphenol F type tetrafunctional epoxy resin, in step (2), the purification method can be to first extract the obtained product with sodium sulfite solution as the extractant, and then extract the obtained extract phase with sodium carbonate solution as the extractant. The obtained extract phase is then dried by vacuum distillation. The concentrations of the sodium sulfite solution and the sodium carbonate solution can each be independently 5–20 wt%, such as 5 wt%, 10 wt%, 15 wt%, 20 wt%, or any value between them.

[0072] In this invention, specific examples of the curing agent include, but are not limited to, at least one of amine curing agents, acid anhydride curing agents, phenolic curing agents, imidazole curing agents, and latent curing agents.

[0073] In this invention, specific examples of the accelerator include, but are not limited to, at least one of imidazole-based curing accelerators, tertiary amine-based curing accelerators, substituted urea-based curing accelerators, phosphorus compound-based curing accelerators, and microencapsulated curing accelerators.

[0074] In this invention, specific examples of the filler include, but are not limited to, at least one of the following: carbon black, silicon dioxide, alumina, talc, calcium carbonate, glass microspheres, metal powder, and polytetrafluoroethylene filler.

[0075] In this invention, specific examples of the coupling agent include, but are not limited to, at least one of: γ-methacryloxypropyltrimethoxysilane, vinyltri(β-methoxyethoxy)silane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, anilinemethyltriethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and γ-ureapropyltriethoxysilane.

[0076] In this invention, specific examples of the additives include, but are not limited to, at least one of the following: stabilizers, polymerization inhibitors, antioxidants, flame retardants, diluents, adhesion promoters, dyes, pigments, defoamers, leveling agents, homogenizers, and ion trapping agents.

[0077] The method for preparing the one-component epoxy adhesive provided by this invention includes: uniformly mixing a first epoxy resin, a second epoxy resin, a curing agent, an accelerator, a filler, a coupling agent, and optional additives to obtain the one-component epoxy adhesive. The mixing method can be either adding all raw materials simultaneously and mixing them together, or adding some raw materials in any order and mixing them first, followed by adding the remaining raw materials and continuing mixing; there are no particular limitations.

[0078] In a preferred embodiment, the mixing method includes uniformly mixing a first epoxy resin, a second epoxy resin, a curing agent, an accelerator, and a coupling agent to obtain an epoxy resin composite; then adding filler to the epoxy resin composite and continuing to mix evenly, passing the mixture through a three-roll mill and grinding it 1 to 5 times, then transferring it to a dual planetary hybrid mixing tank and continuing to stir for 20 to 40 minutes. When the stirring time reaches 1 / 3 to 2 / 3 of the total stirring time, the tank walls are scraped. Finally, the resulting mixture is subjected to vacuum degassing treatment, filtered, and discharged to obtain a high-heat-resistant and high-adhesion single-component epoxy adhesive.

[0079] Furthermore, the present invention also provides the application of the single-component epoxy adhesive as an adhesive or sealant.

[0080] The present invention will be further described below with reference to the embodiments.

[0081] In the following examples and comparative examples, the parts of each raw material refer to parts by weight.

[0082] The raw materials used in the following examples and comparative examples, and their sources, are as follows:

[0083] The bisphenol A type epoxy resin, selected from YD-128 of KUKDO Corporation of South Korea, has the structural formula shown in formula (Ⅳ):

[0084]

[0085] The alicyclic epoxy resin, selected from Celloxide 2021P from Daicel Corporation of Japan, has the structural formula shown in formula (V):

[0086]

[0087] The curing agent was ultrafine pulverized dicyandiamide, purchased from Evonik, brand name Amicure CG-1200G; the accelerator was ultrafine organic urea accelerator, purchased from Evonik, brand name Dyhard UR300; the coupling agent was γ-(2,3-epoxypropoxy)propyltrimethoxysilane, purchased from Shin-Etsu Chemical Co., Ltd., Japan, brand name KBM-403; the filler was fumed silica, selected from Evonik's AEROSIL R202; and the carbon black was purchased from Cabot Corporation, brand name BLACK PEARLS1000.

[0088] Preparation Example 1

[0089] The preparation method of bisphenol F type tetrafunctional epoxy resin (TGEBF) provided by the present invention includes the following specific reaction flow chart and steps:

[0090]

[0091] (1) Take 15g of 4-allyl-2-methoxyphenol in a three-necked flask, add 90mL of water and 5.67g of potassium hydroxide, control the temperature at 40℃, stir the reaction for 30min, slowly add 7.5mL of 37% formaldehyde aqueous solution, after the addition is complete, keep the same conditions and react for another 12h; then add equal amounts of 4-allyl-2-methoxyphenol and potassium hydroxide, add dioxane equal to the volume of water, adjust the temperature to 89℃, stir the reaction for 72h, cool to room temperature, add 36% hydrochloric acid solution dropwise until the system is neutral or weakly acidic, rotary evaporate, extract with an equal volume of ethyl acetate, wash with water, dry by vacuum distillation, and obtain the first intermediate product as a yellow solid.

[0092] (2) Dissolve the first intermediate in 200 mL of acetone, add potassium carbonate to provide an alkaline environment, add 2.5 g of 18-crown ether-6, heat to 75 °C under a nitrogen atmosphere, stir for 30 min, slowly add 40 g of allyl bromide, react for another 8 h, extract with an equal volume of ethyl acetate, wash with water, and dry by vacuum distillation to obtain a white liquid second intermediate.

[0093] (3) Dissolve the second intermediate in dichloromethane or ethyl acetate, add m-chloroperoxybenzoic acid at 40°C, react for 48 h, extract with equal volumes of 10% sodium sulfite solution and 10% sodium carbonate solution, dry under reduced pressure to obtain a yellow viscous product, which is bisphenol F type tetrafunctional epoxy resin.

[0094] The bisphenol F type tetrafunctional epoxy resin 1 H-NMR spectrum and 13 The C-NMR spectra are as follows: Figure 1 and Figure 2 As shown. From Figure 1 It can be seen that the chemical shifts of 6.69 ppm and 6.58 ppm correspond to proton peaks on the benzene ring, the peaks at chemical shifts of 4.15 ppm, 3.93 ppm, and 3.89 ppm correspond to alkoxy groups on the benzene ring, the peak at chemical shift of 4.06 ppm corresponds to a methylene group, the peak at chemical shift of 3.86 ppm corresponds to a methoxy group on the benzene ring, the peaks at chemical shifts of 3.31 ppm, 3.10 ppm, 2.75 ppm, 2.65 ppm, and 2.51 ppm correspond to epoxy groups on the benzene ring, and the peaks at chemical shifts of 2.82 ppm and 2.77 ppm correspond to alkyl groups on the benzene ring. Figure 2 It can be seen that the peaks at chemical shifts of 152.29 ppm, 144.57 ppm, 134.51 ppm, 133.03 ppm, 122.95 ppm, and 111.16 ppm correspond to the benzene ring; the peaks at chemical shifts of 77.39 ppm, 77.08 ppm, and 76.76 ppm correspond to deuterated chloroform; the peak at chemical shift of 73.65 ppm corresponds to an alkoxy group on the benzene ring; the peak at chemical shift of 55.75 ppm corresponds to a methoxy group; the peaks at chemical shifts of 55.52 ppm, 50.63 ppm, 46.85 ppm, and 44.70 ppm correspond to an epoxy group; the peak at chemical shift of 38.58 ppm corresponds to an alkyl group on the benzene ring; and the peak at chemical shift of 29.69 ppm corresponds to a methylene group. Therefore, it can be seen that this bisphenol F type tetrafunctional epoxy resin has the structure shown in formula (Ⅰ).

[0095] Preparation Example 2

[0096] This embodiment illustrates the preparation of the bisphenol F type tetrafunctional epoxy resin provided by the present invention. The specific steps are as follows:

[0097] (1) Take 15g of 4-allyl-2-methoxyphenol in a three-necked flask, add 100mL of water and 13g of magnesium hydroxide, control the temperature at 50℃, stir for 60min, slowly add 10mL of 37% formaldehyde aqueous solution, after the addition is complete, keep the same conditions and react for another 18h; then add equal amounts of 4-allyl-2-methoxyphenol and magnesium hydroxide, add an equal volume of dioxane to water, adjust the temperature to 100℃, stir for 80h, cool to room temperature, add 36% hydrochloric acid solution until the system is neutral or weakly acidic, rotary evaporate, extract with an equal volume of ethyl acetate, wash with water, dry by vacuum distillation, and obtain the first intermediate product as a yellow solid.

[0098] (2) Dissolve the first intermediate in 300 mL of acetone, add sodium hydroxide to provide an alkaline environment, add 4 g of dibenzo-18-crown ether-6, heat to 80 °C under a nitrogen atmosphere, stir for 30 min, slowly add 50 g of allyl chloride, react for another 12 h, extract with an equal volume of ethyl acetate, wash with water, and dry by vacuum distillation to obtain a white liquid second intermediate.

[0099] (3) The second intermediate product was dissolved in dichloromethane, and benzoic acid peroxide was added at 60°C. The reaction was carried out for 90 hours. The product was extracted with equal volumes of 10% sodium sulfite solution and 10% sodium carbonate solution, respectively. The product was dried by vacuum distillation to obtain a yellow viscous product, which is the bisphenol F type tetrafunctional epoxy resin.

[0100] The bisphenol F type tetrafunctional epoxy resin was processed 1 H-NMR and 13 C-NMR characterization confirmed that it has the structure shown in formula (Ⅰ).

[0101] Preparation Example 3

[0102] This embodiment illustrates the preparation of the bisphenol F type tetrafunctional epoxy resin provided by the present invention. The specific steps are as follows:

[0103] (1) Take 15g of 4-allyl-2-methoxyphenol in a three-necked flask, add 70mL of water and 2g of sodium hydroxide, control the temperature at 30℃, stir for 20min, slowly add 4mL of 37% formaldehyde aqueous solution, after the addition is complete, keep the same conditions and react for another 6h; then add equal amounts of 4-allyl-2-methoxyphenol and sodium hydroxide, add dioxane equal to the volume of water, adjust the temperature to 60℃, stir for 48h, cool to room temperature, add 36% hydrochloric acid solution until the system is neutral or weakly acidic, rotary evaporate, extract with equal volume of ethyl acetate, wash with water, dry by vacuum distillation, and obtain the first intermediate product as a yellow solid.

[0104] (2) Dissolve the first intermediate in 100 mL of acetone, add sodium carbonate to provide an alkaline environment, add 1 g of 15 crown ether-5, heat to 60 °C under a nitrogen atmosphere, stir for 30 min, slowly add 30 g of allyl bromide, react for another 4 h, extract with an equal volume of ethyl acetate, wash with water, and dry by vacuum distillation to obtain a white liquid second intermediate.

[0105] (3) The second intermediate product was dissolved in ethyl acetate, and peracetic acid was added at 20°C. The reaction was carried out for 24 hours. The product was extracted with equal volumes of 10% sodium sulfite solution and 10% sodium carbonate solution, respectively. The product was dried by vacuum distillation to obtain a yellow viscous product, which is the bisphenol F type tetrafunctional epoxy resin.

[0106] The bisphenol F type tetrafunctional epoxy resin was processed 1 H-NMR and 13 C-NMR characterization confirmed that it has the structure shown in formula (Ⅰ).

[0107] Example 1

[0108] Accurately weigh each raw material according to the dosage in Table 1. Add 32 parts of bisphenol A type epoxy resin (YD-128), 8 parts of alicyclic epoxy resin (Celloxide 2021P), 40 parts of bisphenol F type tetrafunctional epoxy resin (TGEBF) obtained in Preparation Example 1, 6.5 parts of curing agent dicyandiamide (Amicure CG-1200G), 5 parts of accelerator (Dyhard UR300), 0.5 parts of silane coupling agent (KBM-403), and 0.3 parts of carbon black (BLACK PEARLS1000) to a dispersion mixing device and mix evenly to obtain an epoxy resin composite. Then add 3 parts of fumed silica (AEROSIL) R202) was added to the above epoxy resin composite and mixed evenly. After passing through a three-roll mill, it was ground three times. Then it was transferred to a double planetary hybrid mixing tank and stirred for 20 minutes. When the stirring time reached 1 / 3 of the total stirring time, the wall was scraped. Finally, the resulting mixture was degassed by vacuuming, filtered, and discharged to obtain a single-component epoxy adhesive.

[0109] Example 2

[0110] Accurately weigh each raw material according to the dosage in Table 1. Add 24 parts of bisphenol A type epoxy resin (YD-128), 6 parts of alicyclic epoxy resin (Celloxide 2021P), 30 parts of bisphenol F type tetrafunctional epoxy resin (TGEBF) obtained in Preparation Example 2, 5 parts of curing agent dicyandiamide (Amicure CG-1200G), 3.8 parts of accelerator (Dyhard UR300), 0.5 parts of silane coupling agent (KBM-403), and 0.3 parts of carbon black (BLACK PEARLS1000) to a dispersion mixing device and mix evenly to obtain an epoxy resin composite. Then add 3 parts of fumed silica (AEROSIL) R202) was added to the above epoxy resin composite and mixed evenly. After passing through a three-roll mill, it was ground three times. Then it was transferred to a double planetary hybrid mixing tank and stirred for 40 minutes. When the stirring time reached 2 / 3 of the total stirring time, the wall was scraped. Finally, the resulting mixture was degassed under vacuum, filtered, and discharged to obtain a single-component epoxy adhesive.

[0111] Example 3

[0112] Accurately weigh each raw material according to the dosage in Table 1. Add 40 parts of bisphenol A type epoxy resin (YD-128), 10 parts of alicyclic epoxy resin (Celloxide 2021P), 50 parts of bisphenol F type tetrafunctional epoxy resin (TGEBF) obtained in Preparation Example 3, 8 parts of curing agent dicyandiamide (Amicure CG-1200G), 6.3 parts of accelerator (Dyhard UR300), 0.5 parts of silane coupling agent (KBM-403), and 0.3 parts of carbon black (BLACK PEARLS1000) to a dispersion mixing device and mix evenly to obtain an epoxy resin composite. Then add 3 parts of fumed silica (AEROSIL) R202) was added to the above epoxy resin composite and mixed evenly. After passing through a three-roll mill, it was ground three times. Then it was transferred to a double planetary hybrid mixing tank and stirred for 30 minutes. When the stirring time reached 1 / 3 of the total stirring time, the wall was scraped. Finally, the resulting mixture was degassed under vacuum, filtered, and discharged to obtain a single-component epoxy adhesive.

[0113] Example 4

[0114] Accurately weigh each raw material according to the dosage in Table 1. Add 28 parts of bisphenol A type epoxy resin (YD-128), 7 parts of alicyclic epoxy resin (Celloxide 2021P), 35 parts of bisphenol F type tetrafunctional epoxy resin (TGEBF) obtained in Preparation Example 1, 6 parts of curing agent dicyandiamide (Amicure CG-1200G), 4.4 parts of accelerator (Dyhard UR300), 0.5 parts of silane coupling agent (KBM-403), and 0.3 parts of carbon black (BLACK PEARLS1000) to a dispersion mixing device and mix evenly to obtain an epoxy resin composite. Then add 3 parts of fumed silica (AEROSIL) R202) was added to the above epoxy resin composite and mixed evenly. After passing through a three-roll mill, it was ground three times. Then it was transferred to a double planetary hybrid mixing tank and stirred for 20 minutes. When the stirring time reached 2 / 3 of the total stirring time, the wall was scraped. Finally, the resulting mixture was degassed under vacuum, filtered, and discharged to obtain a single-component epoxy adhesive.

[0115] Example 5

[0116] Accurately weigh each raw material according to the dosage in Table 1. Add 36 parts of bisphenol A type epoxy resin (YD-128), 9 parts of alicyclic epoxy resin (Celloxide 2021P), 45 parts of bisphenol F type tetrafunctional epoxy resin (TGEBF) obtained in Preparation Example 1, 7 parts of curing agent dicyandiamide (Amicure CG-1200G), 5.6 parts of accelerator (Dyhard UR300), 0.5 parts of silane coupling agent (KBM-403), and 0.3 parts of carbon black (BLACK PEARLS1000) to a dispersion mixing device and mix evenly to obtain an epoxy resin composite. Then add 3 parts of fumed silica (AEROSIL) R202) was added to the above epoxy resin composite and mixed evenly. After passing through a three-roll mill, it was ground three times. Then it was transferred to a double planetary hybrid mixing tank and stirred for 30 minutes. When the stirring time reached 2 / 3 of the total stirring time, the wall was scraped. Finally, the resulting mixture was degassed under vacuum, filtered, and discharged to obtain a single-component epoxy adhesive.

[0117] Comparative Example 1

[0118] A one-component heat-resistant epoxy resin composition was prepared according to the method of Example 1, except that the amount of bisphenol F tetrafunctional epoxy resin (TGEBF) was 0, and the other conditions were the same as in Example 1. Specifically:

[0119] Accurately weigh each raw material according to the dosage in Table 1. Add 32 parts of bisphenol A type epoxy resin (YD-128), 8 parts of alicyclic epoxy resin (Celloxide 2021P), 6.5 parts of curing agent dicyandiamide (Amicure CG-1200G), 5 parts of accelerator (DyhardUR300), 0.5 parts of silane coupling agent (KBM-403), and 0.3 parts of carbon black (BLACK PEARLS1000) to a dispersion mixing device and mix evenly to obtain an epoxy resin composite. Then add 3 parts of fumed silica (AEROSIL R202) to the above epoxy resin composite and continue to mix evenly. After passing through a three-roll mill, grind three times. Then transfer to a double planetary hybrid stirring kettle and continue stirring for 20 minutes. When the stirring time reaches 1 / 3 of the total stirring time, scrape the wall. Finally, the obtained mixture is degassed under vacuum, filtered, and discharged to obtain a one-component epoxy adhesive.

[0120] Comparative Example 2

[0121] A one-component heat-resistant epoxy resin composition was prepared according to the method of Example 1, except that the bisphenol F type tetrafunctional epoxy resin (TGEBF) was replaced with the same parts by weight of bisphenol A type epoxy resin (YD-128), and the other conditions were the same as in Example 1. Specifically:

[0122] Accurately weigh each raw material according to the dosage in Table 1. Add 72 parts of bisphenol A type epoxy resin (YD-128), 8 parts of alicyclic epoxy resin (Celloxide 2021P), 6.5 parts of curing agent dicyandiamide (Amicure CG-1200G), 5 parts of accelerator (DyhardUR300), 0.5 parts of silane coupling agent (KBM-403), and 0.3 parts of carbon black (BLACK PEARLS1000) to a dispersion mixing device and mix evenly to obtain an epoxy resin composite. Then add 3 parts of fumed silica (AEROSIL R202) to the above epoxy resin composite and continue to mix evenly. After passing through a three-roll mill, grind three times. Then transfer to a double planetary hybrid stirring tank and continue stirring for 20 minutes. When the stirring time reaches 1 / 3 of the total stirring time, scrape the wall. Finally, after vacuum degassing treatment, filter and discharge the resulting mixture to obtain a one-component epoxy adhesive.

[0123] Comparative Example 3

[0124] A one-component heat-resistant epoxy resin composition was prepared according to the method of Example 1, except that the bisphenol A type epoxy resin (YD-128) was replaced with an alicyclic epoxy resin (Celloxide 2021P) in the same weight proportions. All other conditions were the same as in Example 1. Specifically:

[0125] Accurately weigh each raw material according to the dosage in Table 1. Add 40 parts of alicyclic epoxy resin (Celloxide 2021P), 40 parts of bisphenol F tetrafunctional epoxy resin (TGEBF) obtained in Preparation Example 1, 6.5 parts of curing agent dicyandiamide (Amicure CG-1200G), 5 parts of accelerator (Dyhard UR300), 0.5 parts of silane coupling agent (KBM-403), and 0.3 parts of carbon black (BLACKPEARLS1000) to a dispersion mixing device and mix evenly to obtain an epoxy resin composite. Then add 3 parts of fumed silica (AEROSIL R202) to the above epoxy resin composite and continue to mix evenly. After passing through a three-roll mill, grind three times. Then transfer to a dual planetary hybrid stirring tank and continue stirring for 20 minutes. When the stirring time reaches 1 / 3 of the total stirring time, scrape the wall. Finally, after vacuum degassing treatment, filter and discharge the resulting mixture to obtain a one-component epoxy adhesive.

[0126] Comparative Example 4

[0127] A one-component heat-resistant epoxy resin composition was prepared according to the method of Example 1, except that the alicyclic epoxy resin (Celloxide 2021P) was replaced with the same parts by weight of bisphenol A type epoxy resin (YD-128), and the other conditions were the same as in Example 1. Specifically:

[0128] Accurately weigh each raw material according to the dosage in Table 1. Add 40 parts of bisphenol A type epoxy resin (YD-128), 40 parts of bisphenol F type tetrafunctional epoxy resin (TGEBF) obtained in Preparation Example 1, 6.5 parts of curing agent dicyandiamide (Amicure CG-1200G), 5 parts of accelerator (Dyhard UR300), 0.5 parts of silane coupling agent (KBM-403), and 0.3 parts of carbon black (BLACK PEARLS1000) to a dispersion mixing device and mix evenly to obtain an epoxy resin composite. Then add 3 parts of fumed silica (AEROSIL R202) to the above epoxy resin composite and continue to mix evenly. After passing through a three-roll mill, grind three times. Then transfer to a dual planetary hybrid stirring tank and continue stirring for 20 minutes. When the stirring time reaches 1 / 3 of the total stirring time, scrape the wall. Finally, after vacuum degassing treatment, filter and discharge the resulting mixture to obtain a one-component epoxy adhesive.

[0129] Table 1

[0130]

[0131] Test case

[0132] (1) Bonding strength: The single-component epoxy adhesives obtained in the above examples and comparative examples were coated on stainless steel sheets, and tempered glass sheets were overlapped and pressed together to make test samples. The bonding area was 25.4 mm × 12.5 mm, and the thickness of the adhesive layer was 0.1 mm. The samples were placed in an oven and cured at 140°C for 30 min, and then cured at 160°C for 30 min. Two sheets were pulled apart in opposite directions using a universal testing machine and tested at an ambient temperature of 25°C. The measured force values ​​were recorded as strength (MPa), which is the adhesive strength at room temperature. The cured sample was then kept at 85°C for 10 minutes, and its tensile shear strength (MPa) was tested and recorded at an ambient temperature of 85°C, which is the hot adhesive strength at 85°C. The cured sample was then held at 260°C for 120 seconds, removed, and allowed to cool naturally to room temperature, forming one cycle. This cycle was repeated five times, and the tensile shear strength (MPa) was then tested and recorded at room temperature, which is the high-temperature adhesive strength at 260°C. The results are shown in Table 2.

[0133] (2) Glass transition temperature (Tg): The glass transition temperature was measured using a Q-800 Dynamic Thermomechanical Analyzer (DMA) from TA Instruments (USA). A 42mm × 8mm × 0.3mm film was prepared from the fully cured resin composition. The loss factor (tanδ) was measured as a function of temperature within a temperature range of -40 to 250℃ under liquid nitrogen atmosphere and film stretching mode. The heating rate was 10℃ / min, and the test frequency was 10Hz. This determined the glass transition temperature Tg of the cured resin composition. g (°C). The results are shown in Table 2.

[0134] Table 2

[0135]

[0136] As can be seen from the results in Table 1, the single-component epoxy adhesive provided by this invention has high Tg, bonding strength, and heat resistance. A comparison of Example 1 and Comparative Examples 1-4 shows that when the single-component epoxy adhesive simultaneously contains bisphenol A type epoxy resin, alicyclic epoxy resin, and bisphenol F type tetrafunctional epoxy resin, the Tg and bonding strength are both higher, and the heat resistance is better.

[0137] 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 one-component epoxy adhesive, characterized in that, The single-component epoxy adhesive contains a first epoxy resin, a second epoxy resin, a curing agent, an accelerator, a filler, a coupling agent, and optional additives; the first epoxy resin is a composition of bisphenol A type epoxy resin and an alicyclic epoxy resin; the second epoxy resin is a bisphenol F type tetrafunctional epoxy resin having the structure shown in formula (I). Equation (I) In formula (Ⅰ), R1 and R2 are each independently a C1~C5 alkyl group; The first epoxy resin contains 30-50 parts by weight, the second epoxy resin contains 30-50 parts by weight, the curing agent contains 3-15 parts by weight, the accelerator contains 0.1-10 parts by weight, the filler contains 2-60 parts by weight, the coupling agent contains 0.1-2 parts by weight, and the additives contain 0.1-10 parts by weight. The weight ratio of bisphenol A type epoxy resin to alicyclic epoxy resin in the first epoxy resin is 1:(0.1~0.5).

2. The one-component epoxy adhesive according to claim 1, characterized in that, The weight ratio of the first epoxy resin to the second epoxy resin is 1:(0.8~1.5).

3. The one-component epoxy adhesive according to claim 1, characterized in that, The bisphenol F type tetrafunctional epoxy resin is prepared by a method including the following steps: (1) 4-allyl-2-alkoxyphenol with the structure shown in formula (II) and formaldehyde are subjected to an addition reaction in the presence of a first alkaline medium and water. The resulting addition reaction product is then subjected to a condensation reaction with 4-allyl-2-alkoxyphenol in the presence of a second alkaline medium and an organic solvent and purified to obtain the first intermediate product. (2) The first intermediate product was subjected to a substitution reaction with an allyl halide compound having the structure shown in formula (III) in the presence of a phase transfer catalyst and a third alkaline medium, and then purified to obtain the second intermediate product. (3) The second intermediate product was oxidized in the presence of an oxidant and then purified to obtain bisphenol F type tetrafunctional epoxy resin; Formula (II), Formula (Ⅲ), In formula (II), R3 is a C1~C5 alkyl group; In equation (Ⅲ), X is a halogen atom.

4. The one-component epoxy adhesive according to claim 3, characterized in that, In step (1), the molar ratio of 4-allyl-2-alkoxyphenol to formaldehyde used in the addition reaction is (0.5~2):

1.

5. The one-component epoxy adhesive according to claim 3, characterized in that, In step (1), the molar ratio of 4-allyl-2-alkoxyphenol used in the condensation reaction to that used in the addition reaction is (0.9~1.1):

1.

6. The one-component epoxy adhesive according to claim 3, characterized in that, In step (1), the first alkaline medium and the second alkaline medium are each independently selected from at least one of potassium hydroxide, sodium hydroxide, magnesium hydroxide, calcium hydroxide, barium hydroxide, sodium carbonate and potassium carbonate.

7. The one-component epoxy adhesive according to claim 3, characterized in that, In step (1), the conditions for the addition reaction include a temperature of 30~50℃ and a time of 5~20h.

8. The one-component epoxy adhesive according to claim 3, characterized in that, In step (1), the conditions for the condensation reaction include a temperature of 60~100℃ and a time of 48~100h.

9. The one-component epoxy adhesive according to claim 3, characterized in that, In step (2), the molar ratio of the amount of the allyl halide compound used to the total amount of 4-allyl-2-alkoxyphenol used in the addition reaction and the condensation reaction is (1.5~2.5):

1.

10. The one-component epoxy adhesive according to claim 3, characterized in that, In step (2), the allyl halogenated compound is allyl bromide and / or allyl chloride.

11. The one-component epoxy adhesive according to claim 3, characterized in that, In step (2), the phase transfer catalyst is selected from at least one of cyclic crown ethers, polyethers and ammonium compounds.

12. The one-component epoxy adhesive according to claim 3, characterized in that, In step (2), the third alkaline medium is selected from at least one of potassium hydroxide, sodium hydroxide, magnesium hydroxide, calcium hydroxide, barium hydroxide, sodium carbonate, and potassium carbonate.

13. The one-component epoxy adhesive according to claim 3, characterized in that, In step (2), the conditions for the substitution reaction include a temperature of 60-80°C and a time of 4-12 hours.

14. The one-component epoxy adhesive according to claim 3, characterized in that, In step (3), the oxidant is peroxide and / or hydrogen peroxide.

15. The one-component epoxy adhesive according to claim 3, characterized in that, In step (3), the conditions for the oxidation reaction include a temperature of 20~60°C and a time of 24~96 hours.

16. The one-component epoxy adhesive according to any one of claims 1 to 15, characterized in that, The curing agent is selected from at least one of amine curing agents, acid anhydride curing agents, phenolic curing agents, imidazole curing agents, and latent curing agents.

17. The one-component epoxy adhesive according to any one of claims 1 to 15, characterized in that, The accelerator is selected from at least one of imidazole-based curing accelerators, tertiary amine-based curing accelerators, substituted urea-based curing accelerators, phosphorus compound-based curing accelerators, and microencapsulated curing accelerators.

18. The one-component epoxy adhesive according to any one of claims 1 to 15, characterized in that, The filler is selected from at least one of carbon black, silica, alumina, talc, calcium carbonate, glass microspheres, metal powder, and polytetrafluoroethylene filler.

19. The one-component epoxy adhesive according to any one of claims 1 to 15, characterized in that, The coupling agent is selected from at least one of γ-methacryloxypropyltrimethoxysilane, vinyltri(β-methoxyethoxy)silane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, anilinemethyltriethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and γ-ureapropyltriethoxysilane.

20. The one-component epoxy adhesive according to any one of claims 1 to 15, characterized in that, The additives are selected from at least one of stabilizers, polymerization inhibitors, antioxidants, flame retardants, diluents, adhesion promoters, dyes, pigments, defoamers, leveling agents, homogenizers, and ion trapping agents.

21. A method for preparing the one-component epoxy adhesive according to any one of claims 1 to 20, characterized in that, The method includes: mixing a first epoxy resin, a second epoxy resin, a curing agent, an accelerator, a filler, a coupling agent, and optional additives evenly to obtain the single-component epoxy adhesive.

22. The use of the single-component epoxy adhesive according to any one of claims 1 to 20 as an adhesive or sealant.

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