A UV-thermal dual-curing adhesive, its preparation method and application

Abstract

This invention provides a UV-thermal dual-curing adhesive, its preparation method, and its application. The UV-thermal dual-curing adhesive comprises specific proportions of epoxy resin, photoinitiator, thermal initiator, and filler, wherein the filler includes D... 50 Nano-sized silica with a particle size ≤100nm and D 50 Silicon micropowder with a particle size ≥ 0.5 μm; by selecting two different silicon materials with different particle sizes to form a filler to modify epoxy resin, and adding two initiators, photoinitiator and thermal initiator, the resulting adhesive can be UV-thermal dual-cured, and has excellent bonding performance and weather resistance after complete curing.

Description

Technical Field

[0001] This invention belongs to the field of adhesive technology, specifically relating to a UV-thermal dual-curing adhesive, its preparation method, and its application. Background Technology

[0002] Adhesives, as an important industrial material, have been applied in various fields such as electronics, communications, aviation, aerospace, and medicine. However, with the continuous improvement of material performance requirements, traditional single-curing adhesives are no longer sufficient to meet the needs of use in complex environments. Therefore, developing adhesives with dual curing mechanisms and superior performance has become a research hotspot in the industry.

[0003] In terms of curing technology, UV curing technology has become a research hotspot in recent years due to its advantages such as rapid curing, high production efficiency, energy saving, and environmental protection. However, single UV curing products have disadvantages such as incomplete curing, inability to cure opaque or irregularly shaped products, and the interference of colored pastes on light absorption, which affects curing efficiency. In order to overcome these shortcomings, researchers began to explore dual curing system products, among which the UV-thermal dual curing method emerged.

[0004] The UV-thermal dual-curing method combines the advantages of UV light curing and thermal curing. It achieves rapid curing through UV light irradiation and enhances the curing degree and performance through heat curing. This dual-curing mechanism allows the adhesive to fully utilize the advantages of both curing methods during the curing process, resulting in a superior adhesive product. This is particularly important in structural bonding of metal substrates, where UV light curing is used for rapid initial positioning, followed by thermal curing to further improve adhesion, tensile strength, water resistance, high-temperature resistance, and aging resistance. However, the development of UV-thermal dual-curing adhesives faces a series of technical challenges. Firstly, how to effectively combine UV light curing and thermal curing mechanisms to achieve the dual-curing effect; secondly, how to control the curing speed and degree of curing to meet the needs of different application scenarios; and thirdly, the adhesive's adhesion, tensile strength, water resistance, high-temperature resistance, and aging resistance must also be considered.

[0005] Currently, UV-thermal dual-curing adhesive products and research mainly fall into the following categories: First, two-component hybrid systems: (acrylic) radical-(epoxy) cationic hybrid systems, which feature fast curing speed and high hardness. However, because they simply physically mix two types of resins with completely different reaction mechanisms and their curing agents, they suffer from poor miscibility, poor storage stability, and poor bonding performance. Second, single-component systems: single-component systems in which the resin contains both acrylic double bonds and epoxy groups at both ends. These systems have excellent storage stability, but the resin has a large molecular weight and high viscosity, resulting in poor compatibility with propionic acid resins and epoxy resins. The excessively high viscosity of the adhesive leads to poor process adjustability and poor bonding performance.

[0006] Therefore, in order to address the above-mentioned technical problems, there is an urgent need to develop a UV-thermal dual-curing adhesive with excellent bonding and weather resistance properties. Summary of the Invention

[0007] In view of the shortcomings of the prior art, the purpose of this invention is to provide a UV-thermal dual-curing adhesive, its preparation method and application. The UV-thermal dual-curing adhesive has excellent bonding performance and weather resistance, is suitable for bonding to metal substrates, and can be widely used in multiple fields such as automobiles, electronics, and communications.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides a UV-thermal dual-curing adhesive, wherein the UV-thermal dual-curing adhesive comprises the following components by weight:

[0010]

[0011] The packing includes D 50 Nano-sized silica with a particle size ≤100nm and D 50 Silicon micropowder with a particle size ≥ 0.5 μm.

[0012] The UV-thermal dual-curing adhesive provided by this invention comprises specific proportions of epoxy resin, photoinitiator, thermal initiator, and filler, and the filler is limited to include D. 50 Nano-sized silica with a particle size ≤100nm and D 50 Silicon micropowder with a particle size ≥ 0.5 μm; by selecting and combining silicon materials with different particle sizes, they are used to modify epoxy resin as fillers. At the same time, two initiators, photoinitiator and thermal initiator, are added to make the resulting adhesive have the characteristics of UV-thermal dual curing, and after complete curing, it has excellent bonding performance and weather resistance.

[0013] The amount of epoxy resin used can be 10 parts by weight, 15 parts by weight, 20 parts by weight, 25 parts by weight, 30 parts by weight, 35 parts by weight, or 40 parts by weight, etc.

[0014] The amount of the photoinitiator can be 0.5 parts by weight, 1 part by weight, 2 parts by weight, 3 parts by weight, 4 parts by weight, or 5 parts by weight, etc.

[0015] The amount of the thermal initiator can be 0.1 parts by weight, 0.2 parts by weight, 0.4 parts by weight, 0.6 parts by weight, 1 part by weight, 1.2 parts by weight, 1.5 parts by weight, 2 parts by weight, 2.5 parts by weight, or 3 parts by weight, etc.

[0016] The amount of the filler can be 30 parts by weight, 35 parts by weight, 40 parts by weight, 45 parts by weight, 50 parts by weight, 55 parts by weight, 60 parts by weight, 65 parts by weight, or 70 parts by weight, etc.

[0017] The D of the nano-silica 50 The particle size can be 100nm, 70nm, 60nm, 50nm, 40nm, 30nm, 20nm or 10nm, etc.

[0018] The silicon micropowder D 50 The particle size can be 0.5μm, 0.6μm, 0.7μm, 0.8μm, 0.9μm, 1μm, 2μm, 5μm or 10μm, etc.

[0019] Preferably, the D of the nano-silica 50 The particle size is 40–80 nm; further limiting the D of the nano-silica 50 Particle size within the above range can further improve the bonding performance and weather resistance of the obtained UV-thermal dual-curing adhesive after complete curing.

[0020] Preferably, the D of the silicon micropowder 50 The particle size is 1–2 μm; further limiting the D of the micro powder 50 Particle size within the above range can further improve the bonding performance and weather resistance of the obtained UV-thermal dual-curing adhesive after complete curing.

[0021] Preferably, the nano-silica is nano-silica with a surface modified by (3-epoxypropoxypropyl)trimethoxysilane.

[0022] Preferably, the silicon micropowder is silicon micropowder surface-modified with (3-epoxypropoxypropyl)trimethoxysilane.

[0023] In this invention, there are no special restrictions on the source of the nano-silica modified with (3-epoxypropoxypropyl)trimethoxysilane and the silicon micropowder modified with (3-epoxypropoxypropyl)trimethoxysilane. Commercially available products can be purchased directly, or they can be prepared by ourselves.

[0024] Preferably, the mass ratio of the nano-silica to the silicon micropowder is 1:(5-35), for example, 1:5, 1:10, 1:15, 1:20, 1:25, 1:30 or 1:35.

[0025] Preferably, the epoxy resin includes any one or a combination of at least two of alicyclic epoxy resin, bisphenol A epoxy resin, bisphenol F epoxy resin, phenolic epoxy resin, vinyl epoxy resin, siloxane epoxy resin, hydrogenated bisphenol A epoxy resin, or hydrogenated bisphenol F epoxy resin.

[0026] Preferably, the alicyclic epoxy resin comprises any one or a combination of at least two of the following: bis-(3,4-epoxycyclohexylmethyl)adipate, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexylcarboxylate, di-4-epoxycyclohexane, 1,2:5,6-diepoxyhexahydroindane, 4-vinylepoxycyclohexane, 3,4-epoxycyclohexylmethacrylate, or 4,5-epoxycyclohexane-1,2-dicarboxylic acid diglycidyl ester.

[0027] Preferably, the photoinitiator comprises a cationic photoinitiator.

[0028] Preferably, the cationic photoinitiator comprises any one or a combination of at least two of aromatic iodonium salts, aromatic sulfonium salts, aromatic diazoonium salts, aromatic phosphonium salts, or aromatic ferrocene salts.

[0029] Preferably, the aromatic iodonium salt includes any one or a combination of at least two of diarylpentofluorophenylboronic acid iodonium salt, diarylhexafluorophosphate iodonium salt, or diarylhexafluoroantimonyate iodonium salt.

[0030] Preferably, the aromatic sulfonium salt includes triarylhexafluoroantimony sulfonium salt and / or triarylhexafluorophosphate sulfonium salt.

[0031] Preferably, the ferrocene salt includes ferrocene hexafluorophosphate.

[0032] Preferably, the thermal initiator comprises a cationic thermal initiator.

[0033] Preferably, the cationic thermal initiator includes any one or a combination of at least two of CXC1612, Vicbase TC3631, Vicbase TC3632, Vicbase TC3634, CTI-100, CTI-200 or CTI-300.

[0034] Preferably, the UV-thermal dual-curing adhesive further includes an active diluent.

[0035] Preferably, the content of the reactive diluent in the UV-thermal dual-curing adhesive is 10 to 40 parts by weight, such as 10 parts by weight, 15 parts by weight, 20 parts by weight, 25 parts by weight, 30 parts by weight, 35 parts by weight, or 40 parts by weight.

[0036] Preferably, the reactive diluent includes any one or a combination of at least two of the following: alkenyl ether reactive diluents, ketene diethanol condensate reactive diluents, epoxy reactive diluents, epoxidized triglyceride reactive diluents, oxetane reactive diluents, or mixed reactive diluents containing epoxy and enol ether groups.

[0037] Preferably, the alkenyl ether reactive diluent includes any one or a combination of at least two of triethylene glycol divinyl ether (DVE-3), 4-hydroxybutyl vinyl ether (HBVE), or glycerol carbonate propylene ether (PEPC);

[0038] Preferably, the oxetine-based reactive diluent comprises any one or a combination of at least two of the following: 3-ethyl-3-oxetane methanol, 3-ethyl-3-chloromethyloxetane, 3,3-[oxybismethylene]bis[3-ethyl]oxetane, 3-ethyl-3-[(2-ethyl)-hexyloxymethyl]oxetane, 3-ethyl-3-[(benzyloxy)methyl]oxetane, 3-ethyl-3-[(phenoxy)methyl]oxetane, or 3-ethyl-3-allylmethoxyoxetane.

[0039] Preferably, the UV-thermal dual-curing adhesive further includes a thixotropic agent.

[0040] Preferably, the thixotropic agent content in the UV-thermal dual-curing adhesive is 1 to 10 parts by weight, such as 1 part by weight, 2 parts by weight, 4 parts by weight, 6 parts by weight, 8 parts by weight, or 10 parts by weight.

[0041] Preferably, the thixotropic agent comprises fumed silica and / or precipitated silica.

[0042] Preferably, the UV-thermal dual-curing adhesive further includes an antioxidant.

[0043] Preferably, the antioxidant content in the UV-thermal dual-curing adhesive is 0.1 to 2 parts by weight, such as 0.1 parts by weight, 0.2 parts by weight, 0.4 parts by weight, 0.6 parts by weight, 0.8 parts by weight, 1 part by weight, 1.3 parts by weight, 1.6 parts by weight, 1.9 parts by weight, or 2 parts by weight.

[0044] Preferably, the antioxidant includes any one or a combination of at least two of aromatic amine antioxidants, ketone amines, aldehyde amines, or hindered phenolic antioxidants.

[0045] Preferably, the aromatic amine antioxidant includes diaryl secondary amines and / or p-phenylenediamine.

[0046] Preferably, the hindered phenolic antioxidant includes one or a combination of at least two of 2,6-di-tert-butyl-4-methylphenol, antioxidant AO-20, or antioxidant 1076.

[0047] In a second aspect, the present invention provides a method for preparing a UV-thermal dual-curing adhesive as described in the first aspect, the method comprising: mixing an epoxy resin, a photoinitiator, a thermal initiator, a filler, optionally an active diluent, optionally an antioxidant, and optionally a thixotropic agent under yellow light conditions to obtain the UV-thermal dual-curing adhesive.

[0048] Preferably, the preparation method includes: under yellow light conditions, first mixing epoxy resin, photoinitiator and reactive diluent evenly, adding thixotropic agent and mixing evenly, then adding nano-silica and mixing evenly, then adding silica powder and mixing evenly, then adding antioxidant and mixing evenly, and finally adding thermal initiator and mixing evenly to obtain the UV-thermal dual-curing adhesive.

[0049] Thirdly, the present invention provides an application of the UV-thermal dual-curing adhesive as described in the first aspect in the bonding of metal substrates.

[0050] Compared with the prior art, the present invention has the following beneficial effects:

[0051] The UV-thermal dual-curing adhesive provided by this invention comprises specific proportions of epoxy resin, photoinitiator, thermal initiator, and filler, wherein the filler includes D 50 Nano-sized silica with a particle size ≤100nm and D 50 Silica powder with a particle size ≥ 0.5 μm; by selecting silica and silica powder with different particle sizes to form a filler to modify epoxy resin, and adding photoinitiator and thermal initiator to initiate the process, the resulting adhesive can be UV-thermal dual-cured, and has excellent bonding performance and weather resistance after complete curing. Detailed Implementation

[0052] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0053] The following is some information about the raw materials used in the examples and comparative examples:

[0054] (A) Epoxy resin

[0055] A-1: Bis-(3,4-epoxycyclohexylmethyl) adipate;

[0056] A-2: 3,4-Epoxycyclohexylmethyl 3,4-Epoxycyclohexylcarbamate;

[0057] A-3: 4,5-Epoxycyclohexane-1,2-dicarboxylic acid diglycidyl ester.

[0058] (B) Photoinitiator

[0059] B-1: Sulfonium diphenyl-(4-phenylthio)phenyl hexafluoroantimonyate.

[0060] (C) Thermal initiator

[0061] C-1: CXC1612, purchased from King's Chemical Company, USA.

[0062] (D) Packing

[0063] D-1-50: Nano-silica with surface modification of (3-epoxypropoxypropyl)trimethoxysilane, D 50 The particles with a diameter of 50 nm were obtained by mixing (3-epoxypropoxypropyl)trimethoxysilane and unmodified nano-silica in toluene at 90 °C for 6 h in a mass ratio of 6:1.

[0064] D-2-70: Nano-silica with surface modification of (3-epoxypropoxypropyl)trimethoxysilane, D 50 The particles with a diameter of 70 nm were obtained by mixing (3-epoxypropoxypropyl)trimethoxysilane and unmodified nano-silica in toluene at 90 °C for 6 h in a mass ratio of 6:1.

[0065] D-3-100: Nano-silica with surface modification of (3-epoxypropoxypropyl)trimethoxysilane, D 50 The particles with a diameter of 100 nm were obtained by mixing (3-epoxypropoxypropyl)trimethoxysilane and unmodified nano-silica in toluene at 90 °C for 6 h with a mass ratio of 6:1.

[0066] D-4-150: Nano-silica modified with (3-epoxypropoxypropyl)trimethoxysilane, D 50 The particle size was 150 nm, obtained by mixing (3-epoxypropoxypropyl)trimethoxysilane and unmodified nano-silica in toluene at 90 °C for 6 h in a mass ratio of 6:1.

[0067] D-5-50: Unmodified nano-silica, D 50 The particle size is 50 nm;

[0068] D-6-0.3: Silica micropowder surface-modified with (3-epoxypropoxypropyl)trimethoxysilane, D 50The particle size was 0.3 μm, obtained by mixing (3-epoxypropoxypropyl)trimethoxysilane and unmodified silica powder in toluene at 90 °C for 6 h in a mass ratio of 1:2.

[0069] D-7-0.5: Silica micropowder surface-modified with (3-epoxypropoxypropyl)trimethoxysilane, D 50 The particle size was 0.5 μm, obtained by mixing (3-epoxypropoxypropyl)trimethoxysilane and unmodified silica powder in toluene at 90 °C for 6 h in a mass ratio of 1:2.

[0070] D-8-1.0: Silica micropowder surface-modified with (3-epoxypropoxypropyl)trimethoxysilane, D 50 The particle size was 1.0 μm, obtained by mixing (3-epoxypropoxypropyl)trimethoxysilane and unmodified silica powder in toluene at 90 °C for 6 h in a mass ratio of 1:2.

[0071] D-9-2.0: Silica micropowder surface-modified with (3-epoxypropoxypropyl)trimethoxysilane, D 50 The particle size was 2.0 μm, obtained by mixing (3-epoxypropoxypropyl)trimethoxysilane and unmodified silica powder in toluene at 90 °C for 6 h in a mass ratio of 1:2.

[0072] D-10-3.0: Silica micropowder surface-modified with (3-epoxypropoxypropyl)trimethoxysilane, D 50 The particle size was 3.0 μm, obtained by mixing (3-epoxypropoxypropyl)trimethoxysilane and unmodified silica powder in toluene at 90 °C for h with a mass ratio of 1:2.

[0073] D-11-2.0: Unmodified micronized powder, D 50 The particle size is 2.0 μm.

[0074] (E) Reactive diluent

[0075] E-1: 3-Ethyl-3-allylmethoxyoxane.

[0076] (F) Thixotropic agent

[0077] F-1: Fumed silica.

[0078] (G) Antioxidant

[0079] G-1: Hindered phenolic antioxidant, specifically antioxidant AO-20.

[0080] Examples 1-12, Comparative Examples 1-5

[0081] Examples 1-12 and Comparative Examples 1-5 each provide a UV-thermal dual-curing adhesive, the components of which are shown in Table 1 and Table 2, respectively.

[0082] In Tables 1 and 2, the unit of measurement for each component is "parts by weight";

[0083] Table 1

[0084]

[0085] Table 2

[0086]

[0087] The preparation methods of the UV-thermal dual-curing adhesives provided in Examples 1-12 and Comparative Examples 1-5 include the following steps:

[0088] Under yellow light conditions, epoxy resin, reactive diluent, and cationic photoinitiator are first mixed evenly in a high-speed dispersion tank and heated to 80°C to dissolve the cationic photoinitiator. Then, the high-speed dispersion tank is placed in a homogenizer and stirred at 1500 rpm for 2 minutes. Next, thixotropic agent is added, and the mixture is placed in the homogenizer and stirred at 1500 rpm for 2 minutes. Then, nano-silica is added and stirred at 1500 rpm for 2 minutes. Next, silica powder is added and stirred at 1500 rpm for 2 minutes. Then, antioxidant is added and stirred at 1500 rpm for 2 minutes. The mixture is cooled, and finally, cationic thermal initiator is added and stirred at 1500 rpm for 2 minutes (vacuum degassing). The mixture is cooled, placed in the homogenizer, and stirred at 1500 rpm for 2 minutes (vacuum degassing). The mixture is then packaged into tubes and frozen for storage to obtain the UV-thermal dual-curing adhesive.

[0089] Performance testing:

[0090] (1) Initial tensile shear strength: The test was conducted according to the test method provided in GB / T7124-2008; the test substrates were AlSi. 12 / AlSi 12 And anodized aluminum / anodized aluminum; curing conditions are: using a 365nm LED UV curing machine, first at an energy density of 150mW / cm². 2 It is light-cured under UV light for 4 seconds, and then heat-cured at 80°C for 60 minutes.

[0091] (2) Tensile shear strength after aging at 85℃ / 85% humidity: The samples were aged at 85℃ / 85% humidity for 1000h and then tested according to the test method provided in GB / T7124-2008; the test substrates were AlSi. 12 / AlSi 12And anodized aluminum oxide / anodized aluminum oxide; curing conditions are: first at an energy density of 150mW / cm³ 2 It is light-cured under UV light for 4 seconds, and then heat-cured at 80°C for 60 minutes.

[0092] The UV-thermal dual-curing adhesives provided in Examples 1-12 and Comparative Examples 1-5 were tested according to the above test methods. The test results are shown in Table 3.

[0093] Table 3

[0094]

[0095] According to the data in Table 3:

[0096] The UV-thermal dual-curing adhesives provided in Examples 1-12 exhibit excellent bonding and weather resistance properties, and are used for bonding AlSi. 12 / AlSi 12 The initial tensile shear strength after complete curing reaches 7.5–11.7 MPa, and the tensile shear strength after aging with double 85 is still as high as 6.9–11.5 MPa; when used to bond anodized aluminum oxide, the initial tensile shear strength after complete curing reaches 7.3–10.6 MPa, and the tensile shear strength after aging with double 85 is still as high as 6.7–10.5 MPa.

[0097] By further optimizing and limiting the particle size of silica and silicon micropowder, as well as their mass ratio, the UV-thermal dual-curing adhesives provided in Examples 1-3 and Example 7 can achieve the best bonding performance and the best weather resistance.

[0098] Comparing the data of Example 1 and Comparative Examples 1-5, it can be seen that the particle size of the added silica is too large (Comparative Example 1), the particle size of the added silica powder is too small (Comparative Example 2), silica is used as the only filler (Comparative Example 3), silica powder is used as the only filler (Comparative Example 4), and no filler is added at all (Comparative Example 5), all of which will lead to a significant decrease in the bonding performance and weather resistance of the obtained UV-thermal dual-curing adhesive.

[0099] The applicant declares that this invention illustrates a UV-thermal dual-curing adhesive, its preparation method, and its application through the above embodiments. However, this invention is not limited to the above embodiments, meaning that this invention does not necessarily rely on the above embodiments for implementation. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of the raw materials in the product, additions of auxiliary components, and selection of specific methods all fall within the protection and disclosure scope of this invention.

Claims

1. A UV-thermal dual-curing adhesive, characterized in that, The UV-thermal dual-curing adhesive comprises the following components in parts by weight: 10-40 parts by weight of epoxy resin Photoinitiator 0.5~5 parts by weight 0.1-3 parts by weight of thermal initiator 30-70 parts by weight of filler; The packing includes D 50 Nano-sized silica and D with a particle size of 40~80 nm 50 Silica powder with a particle size of 1~2 μm; The nano-silica is nano-silica with a surface modified by (3-epoxypropoxypropyl)trimethoxysilane; The silicon micropowder is (3-epoxypropoxypropyl)trimethoxysilane surface-modified silicon micropowder; The mass ratio of nano-silica to silicon micropowder is 1:(5~35).

2. The UV-thermal dual-curing adhesive according to claim 1, characterized in that, The epoxy resin includes any one or a combination of at least two of the following: alicyclic epoxy resin, bisphenol A epoxy resin, bisphenol F epoxy resin, phenolic epoxy resin, vinyl epoxy resin, siloxane epoxy resin, hydrogenated bisphenol A epoxy resin, or hydrogenated bisphenol F epoxy resin.

3. The UV-thermal dual-curing adhesive according to claim 2, characterized in that, The alicyclic epoxy resin includes any one or a combination of at least two of the following: bis-(3,4-epoxycyclohexylmethyl) adipate, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexylcarboxylate, di-4-epoxycyclohexane, 1,2:5,6-diepoxyhexahydroindane, 4-vinylepoxycyclohexane, 3,4-epoxycyclohexylmethacrylate, or 4,5-epoxycyclohexane-1,2-dicarboxylic acid diglycidyl ester.

4. The UV-thermal dual-curing adhesive according to claim 1, characterized in that, The photoinitiator includes a cationic photoinitiator.

5. The UV-thermal dual-curing adhesive according to claim 4, characterized in that, The cationic photoinitiator includes any one or a combination of at least two of the following: aromatic iodonium salts, aromatic sulfonium salts, aromatic diazoonium salts, aromatic phosphonium salts, or ferrocene salts.

6. The UV-thermal dual-curing adhesive according to claim 5, characterized in that, The aromatic iodonium salts include any one or a combination of at least two of the following: diarylpentofluorophenylboronic acid iodonium salt, diarylhexafluorophosphate iodonium salt, or diarylhexafluoroantimony acid iodonium salt.

7. The UV-thermal dual-curing adhesive according to claim 5, characterized in that, The aromatic sulfonium salts include sulfonium triarylhexafluoroantimonate and / or sulfonium triarylhexafluorophosphate.

8. The UV-thermal dual-curing adhesive according to claim 5, characterized in that, The ferrocene salts include ferrocene hexafluorophosphate.

9. The UV-thermal dual-curing adhesive according to claim 1, characterized in that, The thermal initiator includes a cationic thermal initiator.

10. The UV-thermal dual-curing adhesive according to claim 1, characterized in that, The UV-thermal dual-curing adhesive also includes an active diluent.

11. The UV-thermal dual-curing adhesive according to claim 10, characterized in that, The content of reactive diluent in the UV-thermal dual-curing adhesive is 10-40 parts by weight.

12. The UV-thermal dual-curing adhesive according to claim 10, characterized in that, The reactive diluent includes any one or a combination of at least two of the following: alkenyl ether reactive diluents, epoxy reactive diluents, oxetane reactive diluents, or mixed reactive diluents containing epoxy and enol ether groups.

13. The UV-thermal dual-curing adhesive according to claim 12, characterized in that, The alkenyl ether reactive diluent includes any one or a combination of at least two of triethylene glycol divinyl ether, 4-hydroxybutyl vinyl ether, or glyceryl carbonate propylene ether.

14. The UV-thermal dual-curing adhesive according to claim 12, characterized in that, The oxetine diluents include any one or a combination of at least two of the following: 3-ethyl-3-oxetine methanol, 3-ethyl-3-chloromethyloxetine, 3,3-[oxybismethylene]bis[3-ethyl]oxetine, 3-ethyl-3-[(2-ethyl)-hexyloxymethyl]oxetine, 3-ethyl-3-[(benzyloxy)methyl]oxetine, 3-ethyl-3-[(phenoxy)methyl]oxetine, or 3-ethyl-3-allylmethoxyoxetine.

15. The UV-thermal dual-curing adhesive according to claim 1, characterized in that, The UV-thermal dual-curing adhesive also includes an antioxidant.

16. The UV-thermal dual-curing adhesive according to claim 15, characterized in that, The antioxidant content in the UV-thermal dual-curing adhesive is 0.1 to 2 parts by weight.

17. The UV-thermal dual-curing adhesive according to claim 15, characterized in that, The antioxidant includes any one or a combination of at least two of aromatic amine antioxidants or hindered phenolic antioxidants.

18. The UV-thermal dual-curing adhesive according to claim 17, characterized in that, The aromatic amine antioxidants include diaryl secondary amines and / or p-phenylenediamine.

19. The UV-thermal dual-curing adhesive according to claim 17, characterized in that, The hindered phenolic antioxidants include one or a combination of at least two of 2,6-di-tert-butyl-4-methylphenol, antioxidant AO-20, or antioxidant 1076.

20. The UV-thermal dual-curing adhesive according to claim 1, characterized in that, The UV-thermal dual-curing adhesive also includes a thixotropic agent.

21. The UV-thermal dual-curing adhesive according to claim 1, characterized in that, The thixotropic agent content in the UV-thermal dual-curing adhesive is 1 to 10 parts by weight.

22. A method for preparing the UV-thermal dual-curing adhesive as described in any one of claims 1 to 21, characterized in that, The preparation method includes: mixing epoxy resin, photoinitiator, thermal initiator, filler, optionally reactive diluent, optionally antioxidant and optionally thixotropic agent under yellow light conditions to obtain the UV-thermal dual-curing adhesive.

23. The preparation method according to claim 22, characterized in that, The preparation method includes: under yellow light conditions, first mixing epoxy resin, photoinitiator and reactive diluent evenly, adding thixotropic agent and mixing evenly, then adding nano-silica and mixing evenly, then adding silica powder and mixing evenly, then adding antioxidant and mixing evenly, and finally adding thermal initiator and mixing evenly to obtain the UV-thermal dual-curing adhesive.

24. The application of a UV-thermal dual-curing adhesive as described in any one of claims 1 to 21 in bonding metal substrates.

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