Photocuring epoxy adhesive as well as preparation method and application thereof

Abstract

The invention belongs to the field of adhesives, and relates to a photocuring epoxy adhesive as well as a preparation method and application thereof. The light-cured epoxy adhesive contains epoxy resin and a photoinitiator; the epoxy resin contains epoxy resin A and optional epoxy resin B, the epoxy resin A has a structure as shown in a formula (1), and the epoxy resin B is selected from at least one of glycidyl ether epoxy resin, glycidyl ester epoxy resin, glycidyl amine epoxy resin, linear aliphatic epoxy resin and alicyclic epoxy resin; the photoinitiator is a sulfonium salt photoinitiator and / or an iodonium salt photoinitiator. The light-cured epoxy adhesive provided by the invention can be fully cured under the condition that the exposure amount required by a normal epoxy adhesive is about 10%, and can independently provide enough bonding strength on the basis of not adding other curing systems such as a thermocuring system. # imgabs0 #

Description

Technical Field

[0001] The present invention belongs to the field of adhesives, and in particular relates to a light-curing epoxy adhesive and a preparation method and application thereof. Background Art

[0002] Epoxy adhesives are composed of epoxy resins and curing agents, which, upon curing, form a bond with high strength, chemical resistance, and excellent mechanical properties. Due to their excellent bond strength, chemical resistance, and mechanical properties, epoxy adhesives are widely used in industrial manufacturing, construction, electronics, aerospace, automotive, and other fields. In particular, in the consumer electronics sector, epoxy adhesives, with their high impact strength, excellent electrical insulation, and excellent heat resistance, have become a key material for bonding, encapsulating, sealing, and potting circuit boards and electronic components.

[0003] Epoxy adhesives include light-curing epoxy adhesives and heat-curing epoxy adhesives. Light-curing epoxy adhesives cure quickly under light conditions, and their low-temperature curing properties can save a lot of energy, making them particularly suitable for bonding heat-sensitive materials. Heat-curing epoxy adhesives can cure at higher temperatures and are suitable for applications requiring high-temperature curing. Compared to heat-curing epoxy adhesives, light-curing epoxy adhesives can cure at room temperature and cure faster, significantly improving production efficiency. However, in order to receive light exposure, the material bonded by the light-curing epoxy adhesive layer must be a light-transmitting material. In addition, the thickness of the light-curing epoxy adhesive layer and the bonded material will affect the light penetration ability. If the bottom of the adhesive layer cannot receive sufficient light, it will not be fully cured. At the same time, if the thickness of the bonded material is too thick, it cannot guarantee that the adhesive layer can receive sufficient light, and it will also not be fully cured. These factors will inhibit the curing effect. Generally, a single light-curing epoxy system is difficult to provide sufficient bonding strength, especially when the UV light intensity is insufficient or the UV light is affected by the thickness and transmittance of the adhesive layer and the adhesive material. The bonding strength that a simple UV system can provide is often difficult to achieve a high level. However, due to the continuous improvement and change in the structural design of electronic consumer products and automotive-derived electronic devices in the current market, due to the structural limitations of the adhesive parts during bonding, only a low exposure rate can be provided externally during UV light exposure. This low exposure rate affects the ability of existing conventional UV-curing epoxy adhesives to provide sufficient bonding strength, which has become a major pain point. Summary of the Invention

[0004] The first object of the present invention is to provide a light-curing epoxy adhesive that can achieve sufficient curing at low exposure rates and without a heat curing system.

[0005] A second object of the present invention is to provide a method for preparing the above-mentioned light-curing epoxy adhesive.

[0006] A third object of the present invention is to provide an application of the above-mentioned light-curing epoxy adhesive in structural bonding, encapsulation, sealing or potting of consumer electronic devices and automotive electronic devices.

[0007] Specifically, the light-curing epoxy adhesive provided by the present invention contains an epoxy resin and a photoinitiator; the epoxy resin contains an epoxy resin A and an optional epoxy resin B, the epoxy resin A has a structure shown in formula (1), and the epoxy resin B is selected from at least one of a glycidyl ether epoxy resin, a glycidyl ester epoxy resin, a linear aliphatic epoxy resin, and an alicyclic epoxy resin; the photoinitiator is a sulfonium salt photoinitiator and / or an iodonium salt photoinitiator;

[0008]

[0009] The preparation method of the light-curing epoxy adhesive provided by the present invention comprises uniformly mixing epoxy resin, photoinitiator, optional silane coupling agent, polyol toughening agent, thermal initiator and auxiliary agent to obtain the epoxy adhesive.

[0010] The light-curing epoxy adhesive provided by the present invention can fully cure with approximately 10% of the exposure required by conventional epoxy adhesives. Furthermore, it can provide sufficient bonding strength on its own, without the addition of other curing systems, such as thermal curing systems. This is presumably due to the fact that the light-curing epoxy adhesive contains an epoxy resin A with a specific structure, in which both epoxy groups are directly bonded to the same benzene ring. This unique structure results in lower viscosity, a higher electron cloud density near the oxygen atoms, and a UV reaction speed at least 3-5 times faster than other epoxy resins. DETAILED DESCRIPTION

[0011] The light-curing epoxy adhesive provided by the present invention contains an epoxy resin and a photoinitiator, and optionally a silane coupling agent, a polyol toughening agent, a thermal initiator, and an auxiliary agent. The mass ratio of the epoxy resin to the photoinitiator is preferably 100:(0.5-2), such as 100:0.5, 100:0.8, 100:1, 100:1.2, 100:1.5, 100:1.8, 100:2, or any value therebetween. The mass ratio of the silane coupling agent to the epoxy resin is preferably (0.5-1.5):100, such as 0.5:100, 0.8:100, 1:100, 1.2:100, 1.5:100, or any value therebetween. The mass ratio of the polyol toughening agent, the thermal initiator, and the epoxy resin is preferably (10-30):(0.5-1.5):100. The mass ratio of the polyol toughening agent to the epoxy resin can be 10:100, 12:100, 15:100, 18:100, 20:100, 22:100, 25:100, 28:100, 30:100 or any value therebetween. The mass ratio of the thermal initiator to the epoxy resin can be 0.5:100, 0.8:100, 1:100, 1.2:100, 1.5:100 or any value therebetween. The mass ratio of the auxiliary agent to the epoxy resin is preferably (0.5-1.5):100, such as 0.5:100, 0.8:100, 1:100, 1.2:100, 1.5:100 or any value therebetween.

[0012] In the present invention, the epoxy resin A has a structure represented by formula (1), that is, the two epoxy groups on the benzene ring may be substituted in the ortho position, meta position, or para position. Accordingly, the epoxy resin A may specifically have at least one of the structures represented by formula (1-1), formula (1-2), and formula (1-3):

[0013]

[0014] In the present invention, the epoxy resin contains epoxy resin A and optionally epoxy resin B. The epoxy resin B is selected from at least one of glycidyl ether epoxy resins, glycidyl ester epoxy resins, linear aliphatic epoxy resins, and alicyclic epoxy resins. Examples of the glycidyl ether epoxy resins include at least one of bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, and phenolic polyepoxy resins. Examples of the glycidyl ester epoxy resins include at least one of glycidyl phthalate and bisglycidyl tetrahydrophthalate. Examples of the linear aliphatic epoxy resins include at least one of polybutadiene epoxy resins, diglycidyl ethers, and polyglycidyl ethers. Examples of the alicyclic epoxy resins include at least one of dicyclopentadiene dioxide and dicyclopentyl ether dioxide. Particularly preferably, the epoxy resin B is a glycidyl ether epoxy resin and / or an alicyclic epoxy resin. This not only gives the light-curing epoxy adhesive higher bonding strength and mechanical strength, but also gives it an extended curing effect, which can solve the problem that the shadowed parts of the device cannot receive UV light, resulting in the adhesive not being able to cure in these areas. The epoxy resin preferably contains both epoxy resin A and epoxy resin B. This is because if the epoxy resin is entirely epoxy resin A, it will cause the extended curing to be too fast, causing the resin to smoke, and the removal of smoke from the colloid will cause bubbling; if the proportion of epoxy resin A is too small, it will make extended curing difficult or proceed very slowly. The mass ratio of epoxy resin A to epoxy resin B in the epoxy resin is preferably 1: (0.5-2). At this time, the two resins can play a better synergistic role, which is more conducive to improving the bonding strength and mechanical strength of the light-curing epoxy adhesive.

[0015] In the present invention, the photoinitiator is preferably a sulfonium salt photoinitiator and / or an iodonium salt photoinitiator. Specific examples of the sulfonium salt compound include, but are not limited to, at least one of diphenyl-(4-phenylsulfonium)phenylsulfonium hexafluoroantimonate, bis(4-(diphenylsulfonium)phenyl)sulfide-bishexafluoroantimonate, diphenyl-(4-phenylsulfonium)phenylsulfide-bishexafluorophosphate, diphenyl-(4-phenylsulfonium)phenylsulfonium hexafluorophosphate, and benzyl(4-hydroxyphenyl)methylsulfonium hexafluoroantimonate. Specific examples of the iodonium salt compound include, but are not limited to, at least one of 4-isopropyl-4'-methyldiphenyl iodide tetrakis(pentafluorophenyl)borate, bis[4-n-alkyl(C10-13)phenyl]iodonium tetrakis(pentafluorophenyl)borate, 4-isobutylphenyl-4'-methylphenyl iodide hexafluorophosphate, and bis(4-dodecylphenyl)iodonium hexafluoroantimonate. Particularly preferably, the photoinitiator is 4-(phenylthio)phenyldiphenylsulfonium tetrakis(pentafluorophenyl)borate. In this case, the resulting light-curable epoxy adhesive has higher UV activity and is less corrosive to metals. This is because the higher acidity of the borate can enhance the reactivity, while the F ion is bound to the carbon atom of the tetrakis(pentafluorophenyl)borate anion, making it less corrosive.

[0016] In the present invention, the role of the silane coupling agent is to improve the dispersion performance of inorganic substances in the adhesive system, and to improve the bonding performance between the adhesive and the inorganic substrate, thereby increasing the bonding strength. The silane coupling agent can be selected from at least one of aminosilane, epoxysilane, thiosilane, methacryloxysilane, vinylsilane, ureasilane and isocyanatesilane. Specific examples 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.

[0017] In the present invention, the role of the polyol toughening agent is to accelerate the reaction rate of the system and adjust the flexibility of the system. It can be selected from at least one of polyether polyols, polyester polyols, polycarbonate polyols, and polyalkylene polyols. In addition, as mentioned above, the mass ratio of the polyol toughening agent to the epoxy resin is preferably (10-30):100. Controlling the amount of the polyol toughening agent within the above preferred range can accelerate the reaction rate, terminate the chain extension reaction early, and thereby shorten the chain length of the reaction product to a length suitable for migration and delayed curing, giving the light-curing epoxy adhesive an extended curing effect, solving the problem of the adhesive not being able to cure in the shadowed areas of the device due to the lack of UV light exposure. If the amount of the polyol toughening agent is lower than the above preferred range or even not added, the curing speed will be too slow and extended curing will not be achieved. If the amount of the polyol toughening agent is higher than the above preferred range, the chain length will be too short, making it difficult to continue the extended curing. Specific examples of the polyether polyol include, but are not limited to, at least one of ring-opening polymers, random copolymers, and block copolymers of ethylene glycol, propylene glycol, tetrahydrofuran, and 3-methyltetrahydrofuran. Specific examples of the polyester polyol include, but are not limited to, at least one of polyethylene adipate diol, polypropylene adipate diol, polybutylene adipate diol, poly1,4-butylene adipate diol, polyneopentyl adipate diol, and poly1,6-hexanediol adipate diol. Specific examples of the polycarbonate polyol include, but are not limited to, at least one of polycarbonate-1,6-hexanediol polyol, polycarbonate-1,4-butanediol-1,6-hexanediol polyol, polycarbonate-1,5-pentanediol-1,6-hexanediol polyol, polycarbonate-caprolactone hexanediol, polycarbonate-1,4-cyclohexanedimethanol-1,6-hexanediol, polyethylene carbonate, polypropylene carbonate, polybutylene carbonate, and polyhexane carbonate. Specific examples of the polyalkylene polyol include, but are not limited to, at least one of polybutadiene polyol, hydrogenated polybutadiene polyol, and hydrogenated polyisoprene polyol. In addition, the number average molecular weight of the polyol toughening agent is preferably 500 to 1500, such as 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500 or any value therebetween.

[0018] In the present invention, the thermal initiator serves to impart thermal initiation properties to the epoxy adhesive, further improving its curing effect. The thermal initiator may be selected from at least one of peroxide initiators, azo initiators, and persulfate initiators. Specific examples of the peroxide initiator include, but are not limited to, at least one of hydrogen peroxide, ammonium persulfate, sodium persulfate, potassium persulfate, benzoyl peroxide, and tert-butyl benzoyl peroxide. Specific examples of the azo initiator include, but are not limited to, at least one of dimethyl azobisisobutyrate, azobisisobutyramidine hydrochloride, azodicarbonamide, azobisisopropylimidazoline hydrochloride, azoisobutylcyanamide, azobiscyclohexylcarbonitrile, azobiscyanovaleric acid, azobisisopropylimidazoline, azobisisobutyronitrile, azobisisovaleronitrile, and azobisisoheptylonitrile. Specific examples of the persulfate initiator include, but are not limited to, at least one of sodium persulfate, potassium persulfate, and ammonium persulfate.

[0019] In the present invention, the light-curing epoxy adhesive may further contain an auxiliary agent. The type of the auxiliary agent can be selected according to actual conditions, and may include at least one of a thixotropic agent, a stabilizer, an antioxidant, a flame retardant, a diluent, a pigment, a defoaming agent, a leveling agent, a leveling agent, and an ion scavenger.

[0020] The present invention provides a method for preparing a light-curing epoxy adhesive, comprising uniformly mixing an epoxy resin, a photoinitiator, and optionally a silane coupling agent, a polyol toughening agent, a thermal initiator, and an auxiliary agent to obtain the epoxy adhesive. The mixing method is not particularly limited, and the components can be added and mixed in any order.

[0021] The present invention also provides the use of the light-curing epoxy adhesive in structural bonding, encapsulation, sealing or potting of consumer electronic devices and automotive electronic devices.

[0022] The present invention will be described in detail below by way of examples. The examples of the examples are intended to explain the present invention and are not to be construed as limiting the present invention. Where specific techniques or conditions are not specified in the examples, the methods were performed according to the techniques or conditions described in the literature in the art or according to the product specifications. Where the manufacturer of the reagents or instruments is not specified, all are conventional products that can be obtained commercially.

[0023] The raw materials involved in the following examples and comparative examples are as follows: bisphenol A epoxy resin purchased from Daicel Japan, brand 850S; bisphenol F epoxy resin purchased from Mitsubishi Chemical Corporation, brand 806; isosorbide diglycidyl ether purchased from Nagase ChemteX, Japan, brand DENACOL GSR-101; the sulfonium salt cationic photoinitiator is (diphenyl[4-(phenylthio)phenyl]-hexafluoroantimonate sulfonium); the iodonium salt cationic photoinitiator is 4-isopropyl-4'-methyldiphenyliodonium tetrakis(pentafluorophenyl)borate; polyether polyol is purchased from Kukto Chemical Company with the brand name GY420; polyester polyol is purchased from Covestro with the brand name cardyon; polybutadiene polyol is purchased from Nippon Soda Co., Ltd. with the brand name G-2000; fumed silica is a thixotropic agent purchased from Cabot with the brand name TS720; the thermal initiator is hexafluoroantimonate from King Industries with the brand name K-PURE CXC-1612.

[0024] Example 1

[0025] Epoxy resin A (having the structure shown in formula (1-1), purchased from Olin, brand XU 19127), epoxy resin B (bisphenol A epoxy resin), sulfonium salt cationic photoinitiator, silane coupling agent, polyol toughening agent (polyester polyol), thermal initiator (quaternary ammonium hexafluoroantimonate) and fumed silica were added into a dual planetary hybrid stirring kettle according to the feeding ratio in Table 1 and stirred for 30 minutes. The wall was scraped when the stirring time was 15 minutes. After the mixing was completed, vacuum degassing was performed, and the light-curing epoxy adhesive was obtained after discharging.

[0026] Example 2

[0027] Epoxy resin A (having the structure shown in formula (1-1), purchased from Olin, brand XU 19127), epoxy resin B (bisphenol F epoxy resin), iodonium salt cationic photoinitiator, silane coupling agent, polyol toughening agent (polyether polyol), thermal initiator (quaternary ammonium hexafluoroantimonate) and fumed silica were added into a double planetary hybrid stirring kettle according to the feeding ratio in Table 1 and stirred for 30 minutes. The wall was scraped when the stirring time was 15 minutes. After the mixing was completed, vacuum degassing was performed, and the light-curing epoxy adhesive was obtained after discharging.

[0028] Example 3

[0029] Epoxy resin A (having the structure shown in formula (1-1), purchased from Olin, brand XU 19127), epoxy resin B (dicyclopentadiene dioxide), sulfonium salt cationic photoinitiator, silane coupling agent, polyol toughening agent (polybutadiene polyol), thermal initiator (quaternary ammonium hexafluoroantimonate) and fumed silica were added into a double planetary hybrid stirring kettle according to the feeding ratio in Table 1 and stirred for 30 minutes. The wall was scraped when the stirring time was 15 minutes. After the mixing was completed, vacuum degassing was performed, and the light-curing epoxy adhesive was obtained after discharging.

[0030] Example 4

[0031] A light-curing epoxy adhesive was prepared according to the method of Example 1, except that epoxy resin B (bisphenol A epoxy resin) was replaced by epoxy resin B (isosorbide diglycidyl ether) in equal parts by weight. The remaining conditions were the same as in Example 1 to obtain a light-curing epoxy adhesive.

[0032] Example 5

[0033] A light-curing epoxy adhesive was prepared according to the method of Example 1, except that the amounts of epoxy resin A and epoxy resin B were adjusted so that the amount ratio of the two was not within the preferred range. The other conditions were the same as in Example 1 to obtain a light-curing epoxy adhesive.

[0034] Example 6

[0035] A light-curing epoxy adhesive was prepared according to the method of Example 1, except that the epoxy resin B was replaced by the same weight portion of epoxy resin A. The other conditions were the same as in Example 1 to obtain a light-curing epoxy adhesive.

[0036] Example 7

[0037] A light-curing epoxy adhesive was prepared according to the method of Example 1, except that the polyol toughening agent was replaced by a silane coupling agent in equal parts by weight. Other conditions were the same as in Example 1 to obtain a light-curing epoxy adhesive.

[0038] Implementation List 8

[0039] A light-curing epoxy adhesive was prepared according to the method of Example 1, except that the thermal initiator was replaced by a sulfonium salt cationic photoinitiator in equal parts by weight. The other conditions were the same as in Example 1 to obtain a light-curing epoxy adhesive.

[0040] Comparative Example 1

[0041] A light-curing epoxy adhesive was prepared according to the method of Example 1, except that the epoxy resin A was replaced by the same weight parts of 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexylcarboxylate (having the structure shown in formula (2)). The other conditions were the same as those in Example 1 to obtain a light-curing epoxy adhesive.

[0042]

[0043] Comparative Example 2

[0044] A light-curing epoxy adhesive was prepared according to the method of Example 1, except that the epoxy resin A was replaced by the same weight portion of 4-(diglycidylamino)phenyl glycidyl ether (having the structure shown in formula (3)). The remaining conditions were the same as in Example 1 to obtain a light-curing epoxy adhesive.

[0045]

[0046] Comparative Example 3

[0047] A light-curing epoxy adhesive was prepared according to the method of Example 1, except that epoxy resin A and epoxy resin B were replaced with equal parts by weight of 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexylcarboxylate. All other conditions were the same as in Example 1 to obtain a light-curing epoxy adhesive. The amounts of the components used are shown in Table 1.

[0048] Table 1

[0049]

[0050] Note: In Table 1, the amount of each component is in parts by weight.

[0051] Test Case

[0052] (1) Curing effect under low exposure conditions: Prepare a 0.5 mm thick, 5 cm × 0.5 cm long and wide adhesive strip, and use a 365 nm UV point light source at 200 mW / cm 2 The strip was irradiated at one end for 1 second and its curing state was observed after 0 h, 1 h, and 24 h. The curing states included liquid, gel (jelly-like, slightly sticky surface), and solidified. The results are shown in Table 2.

[0053] 2) The light-curing epoxy adhesives obtained in the above examples and comparative examples were coated on stainless steel sheets, and overlapped and pressed with tempered glass sheets with a thickness of 1 mm. The bonding area was 25.4 mm × 5 mm, and the thickness of the adhesive layer was ensured to be 0.1 mm. The samples were measured from the tempered glass using a wavelength of 365 nm and an intensity of 200 mW / cm 2The samples were irradiated with light for 1 second. After standing for 0 hours, 1 hour, and 1 day, the two sheets were pulled apart in opposite directions using a universal testing machine. The resulting force was the bond strength. The results are shown in Table 2.

[0054] 3) Extended curing effect: Prepare a 0.5mm thick, 5cm x 0.5cm long and wide strip of adhesive and use a 365nm UV point light source at 200mW / cm 2 The strip was irradiated at one end for 1 second to observe the extension and curing effect. The results are shown in Table 2.

[0055] Table 2

[0056]

[0057] The results in Table 2 show that the light-curing epoxy adhesive provided by the present invention can achieve full cure at approximately 10% of the exposure required for conventional epoxy adhesives, providing higher bonding strength. A comparison of Example 1 with Example 4 shows that when epoxy resin B is a glycidyl ether epoxy resin and / or a cycloaliphatic epoxy resin, the light-curing epoxy adhesive can achieve higher bonding strength and an extended curing effect. A comparison of Example 1 with Example 5 shows that when the mass ratio of epoxy resin A to epoxy resin B in the epoxy resin is controlled within a preferred range, the bonding strength of the light-curing epoxy adhesive is more effectively improved. A comparison of Example 1 with Example 6 shows that when the light-curing epoxy adhesive does not contain epoxy resin B, the bonding strength after 0 hours of standing can reach 1.5 MPa, and the bonding strength after 1 day of standing is 3.2 MPa. This means that while the initial bonding strength increases, the final bonding strength decreases. A comparison of Example 1 and Example 7 shows that when the light-curing epoxy resin adhesive does not contain a toughening agent, the curing speed is slow, and after 1 hour of static curing, the adhesive remains in a gel state. The final bond strength (after 1 day of static curing) is low, and the adhesive cannot be extended to cure. A comparison of Example 1 and Example 8 shows that when the light-curing epoxy resin adhesive does not contain a thermal initiator, the final bond strength is slightly reduced.

[0058] 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 light-curing epoxy adhesive, characterized in that: The light-curing epoxy adhesive contains an epoxy resin and a photoinitiator; the epoxy resin contains an epoxy resin A and an optional epoxy resin B, the epoxy resin A has a structure shown in formula (1), and the epoxy resin B is selected from at least one of a glycidyl ether epoxy resin, a glycidyl ester epoxy resin, a linear aliphatic epoxy resin, and an alicyclic epoxy resin; the photoinitiator is a sulfonium salt photoinitiator and / or an iodonium salt photoinitiator; 2. The light-curing epoxy adhesive according to claim 1, characterized in that: The mass ratio of the epoxy resin to the photoinitiator is 100:(0.5-2).

3. The light-curing epoxy adhesive according to claim 1, characterized in that: The mass ratio of epoxy resin A to epoxy resin B in the epoxy resin is 1:(0.5-2).

4. The light-curing epoxy adhesive according to claim 1, characterized in that: The epoxy resin B is a glycidyl ether epoxy resin and / or an alicyclic epoxy resin.

5. The light-curing epoxy adhesive according to claim 1, characterized in that: The epoxy adhesive further contains a silane coupling agent; Preferably, the mass ratio of the silane coupling agent to the epoxy resin is (0.5-1.5):100; Preferably, the silane coupling agent is selected from at least one of aminosilane, epoxysilane, thiosilane, methacryloxysilane, vinylsilane, ureasilane and isocyanatesilane.

6. The light-curing epoxy adhesive according to claim 1, characterized in that: The epoxy adhesive further contains a polyol toughening agent and a thermal initiator; Preferably, the mass ratio of the polyol toughening agent, thermal initiator and epoxy resin is (10-30):(0.5-1.5):100; Preferably, the polyol toughening agent is selected from at least one of polyether polyol, polyester polyol, polycarbonate polyol and polyalkylene polyol; Preferably, the thermal initiator is selected from at least one of peroxide initiators, azo initiators and persulfate initiators.

7. The light-curing epoxy adhesive according to claim 1, characterized in that: The epoxy adhesive further contains an auxiliary agent; Preferably, the mass ratio of the auxiliary agent to the epoxy resin is (0.5-1.5):100; Preferably, the auxiliary agent is selected from at least one of a thixotropic agent, a stabilizer, an antioxidant, a flame retardant, a diluent, a pigment, a defoaming agent, a leveling agent, a leveling agent and an ion capture agent.

8. The method for preparing the light-curing epoxy adhesive according to any one of claims 1 to 7, characterized in that: The method comprises the steps of uniformly mixing epoxy resin, photoinitiator, optional silane coupling agent, polyol toughening agent, thermal initiator and auxiliary agent to obtain epoxy adhesive.

9. Use of the light-curing epoxy adhesive according to any one of claims 1 to 7 in structural bonding, encapsulation, sealing or potting of consumer electronic devices and automotive electronic devices.

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