Photo-thermal synergistic stage-cured epoxy resin adhesive film as well as preparation method and application thereof

Abstract

The invention discloses a photo-thermal synergetic stage-cured epoxy resin adhesive film as well as a preparation method and application of the photo-thermal synergetic stage-cured epoxy resin adhesive film. The epoxy resin adhesive film cured at the photo-thermal synergistic stage comprises the following components in parts by weight: 21-27 parts of epoxy resin, 29-35 parts of polyurethane modified epoxy acrylate resin, 0.2-5 parts of a photoinitiator, 25-37 parts of a curing agent, 0.5-10 parts of a latent accelerator, 0.1-2 parts of a stabilizer, 0-5 parts of a coupling agent, 0-2 parts of color paste and 0.5-5 parts of a rheological modifier. Wherein the mass ratio of the epoxy resin to the polyurethane modified epoxy acrylate resin is (35: 65)-(46: 54), and the application of the polyurethane modified epoxy acrylate resin solves the three core problems of insufficient flexibility, contradiction between long-term storage stability and low-temperature curing capacity and insufficient initial use performance in the existing epoxy adhesive film technology. And through resin design and innovation of a curing mechanism, the adhesive film can be synergistically improved in the aspects of high toughness, long storage period, low-temperature curing and excellent process adaptability.

Description

Technical Field

[0001] This invention relates to the field of adhesive materials technology, and in particular to an epoxy resin film that is cured in a photothermal synergistic stage, its preparation method, and its application. Background Technology

[0002] Epoxy resin adhesives, as representatives of high-performance structural adhesives, have received widespread attention from academia and industry due to their advantages such as simple preparation processes and stable performance. They are widely used in high-end manufacturing fields such as electronic packaging, new energy vehicles, and aerospace. In recent years, with the continuous improvement of manufacturing technology, solid epoxy films have been extensively researched and technologically advanced as an important development direction. Compared with liquid adhesives, epoxy films can achieve uniform adhesive layer thickness, good performance consistency, and provide better process control capabilities. Therefore, they show great application potential in semiconductor packaging, composite material bonding, and precision electronic assembly.

[0003] Against this backdrop, developing epoxy resin films that combine excellent stability, good flexibility, and high bonding strength has become a key focus of the industry. However, existing preparation and application technologies still face the following challenges: 1. The inherent brittleness of epoxy resin limits its application in impact-resistant and high-toughness applications. Traditional toughening methods, such as adding plasticizers or elastomer-based toughening agents, can improve toughness to some extent, but often result in a decrease in resistance to damp heat, bonding strength, or process stability, affecting overall performance; 2. Existing epoxy film technologies are limited by their material system design, generally making it difficult to balance storage stability and low-temperature curing performance. The root of this contradiction lies in the fact that achieving low-temperature curing usually requires a highly reactive curing system, which is fundamentally different from maintaining the long shelf life of the film. Conflicts; 3. Existing adhesive film preparation processes are mostly based on solvent evaporation or physical coagulation, which have defects such as insufficient surface drying performance and solvent residue. As a result, the adhesive film is very prone to adhesion in the roll state, leading to a decrease in production yield and inconvenience in use. It is necessary to rely on release paper for separation and protection, which not only increases the complexity and cost of the process, but also may pose a risk of oil separation during long-term storage due to the migration of plasticizer components or unreacted monomers, which directly affects the appearance and reliability of the product. At the same time, this type of adhesive film exhibits high melt viscosity at the curing temperature, resulting in poor interfacial wettability with the substrate, ultimately making it difficult to achieve the design requirements for bonding strength.

[0004] Therefore, there is an urgent need for an epoxy resin film that achieves breakthroughs in material design and curing mechanisms. This film should inherently toughen through structural control, addressing the issue of insufficient toughness without sacrificing adhesion performance. Simultaneously, its curing mechanism should possess staged curing capabilities, resolving the contradiction between poor storage stability and high curing temperatures. Furthermore, the film must exhibit excellent surface drying properties to avoid dependence on release paper and maintain good melt flowability during the curing stage to ensure sufficient interfacial wetting and high-strength adhesion. Such technological advancements will greatly expand the application scope and reliability of epoxy films in high-end manufacturing fields. Summary of the Invention

[0005] The purpose of this invention is to provide an epoxy resin film that cures in a photothermal synergistic stage, along with its preparation method and applications. This aims to address three core problems in existing epoxy film technology: insufficient flexibility, the contradiction between long-term storage stability and low-temperature curing capability, and inadequate initial performance. Through innovation in resin design and curing mechanism, the invention achieves synergistic improvements in the film's high toughness, long shelf life, low-temperature curing capability, and excellent process adaptability.

[0006] To achieve the above objectives, the technical solution adopted by this invention is: a photothermal synergistic curing epoxy resin film, comprising the following components by weight: 21-27 parts epoxy resin, 29-35 parts polyurethane-modified epoxy acrylate resin, 0.2-5 parts photoinitiator, 25-37 parts curing agent, 0.5-10 parts latent accelerator, 0.1-2 parts stabilizer, 0-5 parts coupling agent, 0-2 parts colorant, and 0.5-5 parts rheology modifier, wherein the mass ratio of epoxy resin to polyurethane-modified epoxy acrylate resin is 35:65-46:54. This invention controls the ratio of photocurable double bonds to epoxy groups in the system within a specific range, enabling the photoradical polymerization reaction to rapidly construct a thermoplastic solid network based on a polymer chain structure. This network not only achieves initial curing and surface drying of the film but also melts and flows during the subsequent thermal curing stage, thus providing the necessary conditions for interface wetting and epoxy group curing reactions.

[0007] As a further optimization, the epoxy resin is one or more of bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol A / F type epoxy resin and modified epoxy resin; the epoxy equivalent of the epoxy resin is 150-220 g / eq.

[0008] As a further optimization, the preparation method of the polyurethane-modified epoxy acrylate resin includes the following steps:

[0009] S01) Isophorone diisocyanate and the first compound are dissolved in an anhydrous inert solvent and reacted under nitrogen protection and at 20-30°C for 1-5 hours, wherein the first compound is hydroxyethyl acrylate, hydroxyethyl methacrylate or hydroxypropyl methacrylate, and the molar ratio of the first compound to the isophorone diisocyanate is 1:1.

[0010] S02) The second compound is slowly added dropwise to the reaction system, the reaction temperature is raised to 60-70℃, and the reaction is continued for 1-5 hours. The second compound is selected from one or more of 3-ethyl-3-oxabutane, 1,2-epoxy-4-hydroxymethylcyclohexane, and 1,4-cyclohexanediethanol glycidyl ether, and the molar ratio of the second compound to the isophorone diisocyanate is 1:1.

[0011] After the reaction (S03) is completed, the inert solvent is removed to obtain a polyurethane-modified epoxy acrylate resin. The molecular structural formula of the polyurethane-modified epoxy acrylate resin is as follows:

[0012] ,

[0013] Wherein, R1 is C4H5O2, C5H7O2, or C6H9O2, and R2 is C4H8, C5H8, or C8H 14 O.

[0014] For example, when the first compound is hydroxyethyl acrylate and the second compound is 1,4-cyclohexanediethanol glycidyl ether, the preparation process of polyurethane-modified epoxy acrylate resin is as follows:

[0015] ,

[0016] Based on the above molecular structure, polyurethane-modified epoxy acrylate resin has the following three functions: 1. It provides reinforcement and toughening effect to the film through its polyurethane backbone; 2. The double bond structure contained in the side chain provides free radical reaction sites for the system, achieving the first stage of curing under photoinitiation, transforming the liquid into a solid film; 3. The epoxy groups contained in the side chain and the epoxy resin in the system jointly participate in the second stage of curing under heating conditions, achieving complete cross-linking, while effectively improving the compatibility between the two resins.

[0017] As a further optimization, the photoinitiator is photoinitiator 819, photoinitiator TMO, photoinitiator TPO-L, or photoinitiator ITX.

[0018] As a further optimization, the curing agent is a thiol-based curing agent, including but not limited to Thiocure 430HE, Thiocure 440HE and Thiocure 460HE.

[0019] As a further optimization, the latency promoter is a microcapsule structure promoter, including but not limited to HX-3721, HX-3722, HX-3921HP and HXA3922HP.

[0020] As a further optimization, the stabilizer is barbituric acid.

[0021] As a further optimization, the coupling agent includes one or more of coupling agents KH-550, KH-560, and KH-570.

[0022] As a further optimization, the color paste may contain one or more of carbon black, titanium dioxide, and phthalocyanine blue, depending on the requirements; the rheology modifier may be one or more of fumed silica TS720, R202, and R208.

[0023] This invention also provides a method for preparing an epoxy resin film that is cured in a photothermal synergistic stage, comprising the following steps:

[0024] S1) Accurately weigh each material;

[0025] S2) Epoxy resin, polyurethane modified epoxy acrylate resin, photoinitiator, curing agent, latent accelerator, stabilizer, coupling agent, color paste and rheology modifier are added to the mixing tank in sequence and stirred at a temperature below 25°C for 1-2 hours to obtain a uniform epoxy resin solution.

[0026] S3) Transfer the adhesive to the coating machine and coat the adhesive evenly onto the surface of the release film using the coating roller, controlling the thickness of the adhesive to be 50-250μm;

[0027] S4) The release film coated with adhesive is irradiated with LED ultraviolet light with a wavelength of 360-390nm for 10-60s to initiate free radical polymerization of the double bond groups in the system, achieving preliminary curing and obtaining a dry and solid adhesive film. The release film is peeled off for recycling, and the adhesive film is wound up separately to obtain the finished adhesive film roll. The finished adhesive film roll needs to be stored in an environment of 0-15℃.

[0028] The present invention also provides an application of an epoxy resin film cured in a photothermal synergistic stage. In application, the epoxy resin film cured in the photothermal synergistic stage is die-cut and then applied to the surface of the substrate to be bonded. It is then hot-pressed and cured at 80-100℃ for 10-60 minutes. In this stage, the film first melts into a liquid state, fully wetting the surface of the substrate. Subsequently, the epoxy groups undergo a cross-linking reaction, and the film is completely cured.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. By introducing a self-designed polyurethane-modified epoxy acrylate resin, the polyurethane main chain structure provides an inherent toughening effect for the film system. While significantly improving the toughness and impact resistance of the film, it effectively avoids problems such as decreased heat resistance, loss of bonding strength or deterioration of process stability caused by traditional external toughening agents.

[0031] 2. A staged curing mechanism combining photocuring and thermal curing can be adopted. In the photocuring stage, the adhesive is rapidly shaped and surface-dried through free radical polymerization, enabling rapid winding and storage, and giving the film initial strength and storage stability at room temperature. In the thermal curing stage, the epoxy groups are cross-linked by a latent accelerator at a lower temperature (80-100℃), achieving complete curing. This staged curing mechanism can fundamentally solve the inherent contradiction between high reactivity and storage stability, and has both long storage life and low-temperature curing capability.

[0032] 3. Solvent-free rapid film formation is achieved through the photocuring stage, which fundamentally solves the problem of insufficient surface drying performance caused by traditional processes. It effectively avoids adhesion of film rolls during storage and the resulting decrease in yield. Moreover, it does not rely on release paper, which significantly simplifies the process and reduces costs and material waste.

[0033] 4. It avoids the risk of oil separation caused by the migration of plasticizer components or unreacted monomers, ensuring the appearance and reliability of the product during long-term storage; during the thermosetting stage, the adhesive film exhibits a low melt viscosity, which significantly improves the interfacial wetting ability of the bonded substrate, thereby ensuring that the final bonding strength meets the high standard design requirements. Attached Figure Description

[0034] Figure 1 This is a schematic diagram illustrating the preparation and application process of the epoxy resin film cured in the photothermal synergistic stage according to the present invention. Detailed Implementation

[0035] The following are specific embodiments of the present invention, and the technical solutions of the present invention will be further described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0036] Example 1:

[0037] like Figure 1As shown, a method for preparing an epoxy resin film cured in a photothermal synergistic stage includes the following steps: S1) accurately weighing each material; S2) mixing 22 parts of bisphenol A type epoxy resin, 32 parts of polyurethane modified epoxy acrylate resin, 1.8 parts of photoinitiator TMO, and 30 parts of thiol curing agent Thiocure. 440HE, 5 parts latent accelerator HX-3721, 1.5 parts stabilizer barbituric acid, 3 parts coupling agent KH-560, 2 parts carbon black paste, and 2.7 parts rheology modifier TS720 were added to a mixing tank. The cooling water temperature was set to 25℃, and the mixture was stirred for 60 minutes to ensure thorough mixing of the raw materials and obtain a uniform epoxy resin solution. S3) The obtained solution was transferred to a coating machine and uniformly coated onto the surface of the release film using a coating roller, with the thickness of the solution controlled to be 90-110μm. S4) The release film coated with the solution was passed through an LED ultraviolet light irradiation area with a wavelength of 365nm. The linear speed was adjusted to ensure an irradiation time of 20s to achieve preliminary curing. The film was then cooled to 20℃ to obtain a surface-dry and solidified film. After removing the release film, the film was wound up to obtain the finished film roll, which was stored at 0-15℃.

[0038] The preparation steps of polyurethane-modified epoxy acrylate resin are as follows: S01) Under a nitrogen atmosphere, 1 mol of isoflurane diisocyanate and 1 mol of hydroxyethyl acrylate are dissolved in anhydrous tetrahydrofuran and reacted at 25°C for 2 h; S02) 1 mol of 1,4-cyclohexanediethanol glycidyl ether is slowly added to the reaction system, the temperature is gradually raised to 60°C, and the reaction is continued under reflux for 3 h; S03) After the reaction is completed, the reaction vessel is sealed and cooled to room temperature, and then the tetrahydrofuran solvent is removed by rotary evaporation at 35-40°C to obtain polyurethane-modified epoxy acrylate resin.

[0039] For example Figure 1 As shown, when the above-prepared photothermal synergistic curing epoxy resin film is used, the film is die-cut according to the shape and size of the substrate and covered on the surface of the substrate to be bonded. It is then cured at 80°C for 15 minutes to achieve complete curing, resulting in a well-encapsulated device.

[0040] Example 2:

[0041] A method for preparing a photothermal synergistic curing epoxy resin film includes the following steps: S1) accurately weighing each material; S2) mixing 26 parts of bisphenol A / F type epoxy resin, 33 parts of polyurethane modified epoxy acrylate resin, 0.8 parts of photoinitiator 819, and 30 parts of thiol curing agent Thiocure. 430HE, 4.6 parts latent accelerator HX-3921HP, 0.8 parts stabilizer barbituric acid, 1 part coupling agent KH-550, 2.5 parts titanium dioxide paste, and 1.3 parts rheology modifier R208 were added to a mixing tank. The cooling water temperature was set to 25℃, and the mixture was stirred for 60 minutes to ensure thorough mixing of the raw materials and obtain a uniform epoxy resin solution. S3) The obtained solution was transferred to a coating machine and uniformly coated onto the surface of the release film using a coating roller, with the thickness of the solution controlled to be 130-150μm. S4) The release film coated with the solution was passed through an LED ultraviolet light irradiation area with a wavelength of 370nm. The linear speed was adjusted to ensure an irradiation time of 25s to achieve preliminary curing. The film was then cooled to 15℃ to obtain a surface-dry and solidified film. After removing the release film, the film was wound up to obtain the finished film roll, which was stored at 0-10℃.

[0042] The preparation steps of polyurethane-modified epoxy acrylate resin are as follows: S01) Under a nitrogen atmosphere, 1 mol of isoflurane diisocyanate and 1 mol of hydroxyethyl methacrylate are dissolved in anhydrous tetrahydrofuran and reacted at 25°C for 2 h; S02) 1 mol of 3-ethyl-3-oxabutane methanol is slowly added to the reaction system, the temperature is gradually raised to 70°C, and the reaction is continued under reflux for 5 h; S03) After the reaction is completed, the reaction vessel is sealed and cooled to room temperature, and then the inert solvent is removed by rotary evaporation at 35-40°C to obtain polyurethane-modified epoxy acrylate resin.

[0043] When the photothermal synergistic curing epoxy resin film prepared above is used, the film is die-cut according to the shape and size of the substrate and covered on the surface of the substrate to be bonded. It is then cured at 80°C for 15 minutes to achieve complete curing, resulting in a well-encapsulated device.

[0044] Example 3:

[0045] A method for preparing a photothermal synergistic curing epoxy resin film includes the following steps: S1) accurately weighing each material; S2) mixing 26 parts of bisphenol F type epoxy resin, 37 parts of polyurethane modified epoxy acrylate resin, 1.2 parts of photoinitiator ITX, and 30 parts of thiol curing agent Thiocure. 460HE, 3 parts latent accelerator HXA3922HP, 0.8 parts stabilizer barbituric acid, 0.5 parts coupling agent KH-570, 1.5 parts phthalocyanine blue paste, and 0.8 parts rheology modifier were added to a mixing tank. The cooling water temperature was set to 25℃, and the mixture was stirred for 60 minutes to ensure thorough mixing of the raw materials and obtain a uniform epoxy resin solution. S3) The obtained solution was transferred to a coating machine and uniformly coated onto the surface of the release film using a coating roller, with the thickness of the solution controlled to be 70-90μm. S4) The release film coated with the solution was passed through an LED ultraviolet light irradiation area with a wavelength of 382nm. The linear speed was adjusted to ensure an irradiation time of 15s to achieve preliminary curing. The film was then cooled to 15℃ to obtain a surface-dry and solidified film. After removing the release film, the film was wound up to obtain the finished film roll, which was stored at 0-15℃.

[0046] The preparation steps of polyurethane-modified epoxy acrylate resin are as follows: S01) Under a nitrogen atmosphere, 1 mol of isoflurane diisocyanate and 1 mol of hydroxyethyl methacrylate are dissolved in anhydrous tetrahydrofuran and reacted at 25°C for 2 h; S02) 1 mol of 1,2-epoxy-4-hydroxymethylcyclohexane is slowly added to the reaction system, the temperature is gradually raised to 70°C, and the reaction is continued under reflux for 5 h; S03) After the reaction is completed, the reaction vessel is sealed and cooled to room temperature, and then the inert solvent is removed by rotary evaporation at 35-40°C to obtain polyurethane-modified epoxy acrylate resin.

[0047] When the above-prepared photothermal synergistic curing epoxy resin film is used, the film is die-cut according to the shape and size of the substrate and covered on the surface of the substrate to be bonded. It is then cured at 90°C for 20 minutes to achieve complete curing, resulting in a well-encapsulated device.

[0048] Comparative Example 1:

[0049] The difference between this comparative example and Example 1 is that a flexible thermoplastic epoxy resin (such as HYPOXRK-84L) is used in equal proportion to replace the polyurethane modified epoxy acrylate resin. In addition, the adhesive liquid is initially heated to 70°C and baked for 20-30 minutes to form an adhesive film. After covering the adhesive film with a protective release film, it is wound up.

[0050] Comparative Example 2:

[0051] The difference between this comparative example and Example 1 is that an equal proportion of core-shell toughening agent (such as TP901A) is used to replace the polyurethane modified epoxy acrylate resin, and a solvent (such as butyl ester) is added during mixing. The adhesive solution is initially formed into an adhesive film by heating from 50°C to 90°C to remove the solvent and form an adhesive film. After covering the adhesive film with a protective release film, it is wound up.

[0052] Application Examples:

[0053] The adhesive solutions and films of Examples 1-3 and Comparative Examples 1-2 were subjected to comprehensive performance testing.

[0054] The test methods include: viscosity, according to GB / T 21059-2007, shear rate 20 rpm / s, test temperature 25 / 80℃; elongation at break, using a tensile testing instrument, tensile rate 0.5 mm / min, ambient temperature 25℃; elastic modulus, according to GB / T 2567-2008, using a torsion test, loading speed 30° / min, ambient temperature 25℃; impact strength, according to GB / T 2567-2008, using a simply supported beam impact toughness test, ambient temperature 25℃; curing rate, using DSC, at a specified temperature, testing the enthalpy change of the adhesive during heating, calculating the degree of curing and curing speed of the adhesive; hardness, taking 10g of adhesive film and placing it in a mold, curing the adhesive film according to the curing conditions corresponding to each example / comparative example, and testing the sample hardness using a Shore hardness tester (D); shear strength, according to GB / T 7124-2008, using 304 stainless steel as the substrate, cutting adhesive film samples to 12.5mm*. The substrate was bonded to a thickness of 25mm according to standard, and the tensile shear strength was determined using a tensile testing machine.

[0055] The test results are shown in the table below:

[0056]

[0057] Based on the comparative test data of the embodiments and comparative examples, the photothermal synergistic stage-cured epoxy resin film of the present invention shows significant advantages in key performances compared with existing technology products. The reasons are as follows: 1. Balance between toughening effect and comprehensive performance: The elongation at break and impact strength of Examples 1 to 3 are significantly higher than those of the comparative examples, indicating that the polyurethane modified epoxy acrylate resin effectively avoids the decline in other properties caused by traditional toughening methods while achieving inherent toughening; the excellent performance of hardness and shear strength after secondary curing further confirms that it maintains the mechanical strength and durability of the final product while improving toughness. 2. Synergistic achievement of storage stability and low-temperature curing performance: During the photocuring stage, the adhesive films of Examples 1 to 3 showed normal surface drying and no adhesion after 3 months of storage. The melt viscosity at 80°C was lower than that of the comparative example, demonstrating excellent flow and wetting ability during the thermocuring stage. DSC curing rate data showed that Examples 1 to 3 could achieve a high curing efficiency of over 98.88% under low-temperature conditions of 80-90°C. Moreover, no oil separation was observed in any of the examples during the three-month storage period, and the adhesive film rolls did not stick together. This experimentally verified that the staged curing mechanism successfully resolved the contradiction between storage stability and low-temperature curing performance. 3. Optimization of film-forming process and improvement of interfacial adhesion reliability: The photocuring process freed the adhesive films of the examples from dependence on release paper. No adhesion or oil separation was observed during storage tests, fully verifying the simplicity of the process and the reliability of the products. The lower melt viscosity during the thermocuring stage directly translates into excellent interfacial adhesion performance. The shear strength of Examples 1 to 3 was significantly higher than that of the comparative example, indicating that they have more sufficient wetting of the substrate and stronger interfacial bonding force in practical applications.

[0058] In summary, the test data fully demonstrates that this invention, through material system innovation and photothermal synergistic curing mechanism, has successfully solved the technical bottlenecks of existing epoxy films in terms of toughness balance, storage stability, process adaptability, and bonding reliability, providing a reliable technical solution for the widespread application of high-performance epoxy films.

[0059] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. An epoxy resin film cured in a photothermal synergistic stage, characterized in that, The product comprises the following components by weight: 21-27 parts epoxy resin, 29-35 parts polyurethane-modified epoxy acrylate resin, 0.2-5 parts photoinitiator, 25-37 parts curing agent, 0.5-10 parts latent accelerator, 0.1-2 parts stabilizer, 0-5 parts coupling agent, 0-2 parts colorant, and 0.5-5 parts rheology modifier, wherein the mass ratio of epoxy resin to polyurethane-modified epoxy acrylate resin is 35:65-46:

54.

2. The epoxy resin film cured in a photothermal synergistic stage according to claim 1, characterized in that, The epoxy resin is one or more of bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol A / F type epoxy resin and modified epoxy resin; the epoxy equivalent of the epoxy resin is 150-220 g / eq.

3. The epoxy resin film cured in a photothermal synergistic stage according to claim 1, characterized in that, The preparation method of the polyurethane-modified epoxy acrylate resin includes the following steps: S01) Isophorone diisocyanate and the first compound are dissolved in an anhydrous inert solvent and reacted under nitrogen protection and at 20-30°C for 1-5 hours, wherein the first compound is hydroxyethyl acrylate, hydroxyethyl methacrylate or hydroxypropyl methacrylate, and the molar ratio of the first compound to the isophorone diisocyanate is 1:

1. S02) The second compound is slowly added dropwise to the reaction system, the reaction temperature is raised to 60-70℃, and the reaction is continued for 1-5 hours. The second compound is selected from one or more of 3-ethyl-3-oxabutane, 1,2-epoxy-4-hydroxymethylcyclohexane, and 1,4-cyclohexanediethanol glycidyl ether, and the molar ratio of the second compound to the isophorone diisocyanate is 1:

1. After the reaction (S03) is completed, the inert solvent is removed to obtain a polyurethane-modified epoxy acrylate resin. The molecular structural formula of the polyurethane-modified epoxy acrylate resin is as follows: ， Wherein, R1 is C4H5O2, C5H7O2, or C6H9O2, and R2 is C4H8, C5H8, or C8H 14 O.

4. The epoxy resin film cured in a photothermal synergistic stage according to claim 1, characterized in that, The photoinitiator is photoinitiator 819, photoinitiator TMO, photoinitiator TPO-L, or photoinitiator ITX.

5. The epoxy resin film cured in a photothermal synergistic stage according to claim 1, characterized in that, The curing agent is a thiol-based curing agent.

6. The epoxy resin film cured in a photothermal synergistic stage according to claim 1, characterized in that, The latency promoter is a microcapsule structure promoter.

7. The epoxy resin film cured in a photothermal synergistic stage according to claim 1, characterized in that, The stabilizer is barbituric acid.

8. The epoxy resin film cured in a photothermal synergistic stage according to claim 1, characterized in that, The coupling agent includes one or more of coupling agents KH-550, KH-560, and KH-570.

9. The method for preparing a photothermal synergistic stage-cured epoxy resin film according to any one of claims 1 to 8, characterized in that, Includes the following steps: S1) Accurately weigh each material; S2) Epoxy resin, polyurethane modified epoxy acrylate resin, photoinitiator, curing agent, latent accelerator, stabilizer, coupling agent, color paste and rheology modifier are added to the mixing tank in sequence and stirred at a temperature below 25°C for 1-2 hours to obtain a uniform epoxy resin solution. S3) Transfer the adhesive to the coating machine and coat the adhesive evenly onto the surface of the release film using the coating roller, controlling the thickness of the adhesive to be 50-250μm; S4) The release film coated with adhesive is passed through an ultraviolet light irradiation area with a wavelength of 360-390nm for 10-60s to obtain a surface-dry and solid adhesive film. After peeling off the release film, the adhesive film is wound up to obtain the finished adhesive film roll.

10. The application of the photothermal synergistic stage-cured epoxy resin film according to any one of claims 1 to 8, characterized in that, In application, the epoxy resin film cured in the photothermal synergistic stage is die-cut and applied to the surface of the substrate to be bonded, and then hot-pressed and cured at 80-100℃ for 10-60 minutes.

Images