A modulus uv-controllable dual-curing conductive adhesive film and a preparation method and application thereof

Abstract

The application discloses a modulus UV-controllable double-curing conductive adhesive film and a preparation method and application thereof, and belongs to the technical field of electronic packaging materials. The conductive adhesive film comprises an A component, a B component and a conductive filler. The A component comprises a functional acrylate copolymer prepared from a monomer mixture through solution polymerization. The monomer mixture comprises soft monomers, hard monomers, hydroxyl-containing monomers, epoxy-containing monomers, polymerizable benzophenone photoinitiators, silane coupling agents and free radical polymerization initiators. The B component comprises one or a combination of latent epoxy curing agents, conductive accelerators, curing accelerators and anti-settling agents. The application completely solves the problem of oxygen inhibition, realizes controllable adjustment of the modulus and pressure sensitivity of the adhesive film, has no small molecule residue, has excellent conductive performance and good storage stability.

Description

Technical Field

[0001] This invention relates to the field of electronic packaging materials technology. Specifically, it relates to a UV-tunable dual-curing conductive film, its preparation method, and its application. This conductive film overcomes oxygen inhibition defects, enables controllable modulus adjustment by regulating UV exposure energy, and also possesses advantages such as no small molecule residue, excellent conductivity, and storage stability. Background Technology

[0002] As electronic devices become thinner, lighter, and more high-performance, the assembly precision requirements for camera modules (CCM) and display panels (OLED / LCD) are constantly increasing. Anisotropic conductive film (ACF), as a key material for connecting flexible circuit boards to glass substrates and driver ICs, directly affects the reliability and yield of products.

[0003] Traditional ACF products are mainly divided into two categories: one is thermosetting conductive adhesive film, which achieves connection through high temperature hot pressing, but has the problems of poor adaptability to warped substrates and narrow process window; the other is UV pre-curing conductive adhesive, which usually adds small molecule monomers or reactive diluents to the formulation and achieves pre-curing by initiating free radical polymerization through UV irradiation. However, this type of technology has the following inherent defects: (1) serious oxygen inhibition problem: small molecule free radical polymerization is easily inhibited by oxygen, resulting in incomplete surface curing and affecting the consistency of adhesive film performance; (2) difficult modulus control: free radical polymerization reaction rate is fast and exothermic, and the degree of crosslinking is nonlinear with UV energy, making it difficult to achieve precise control of adhesive film modulus and adhesion; (3) small molecule residue risk: unreacted small molecule monomers will migrate during subsequent high-temperature use, contaminating precision optical components or causing increased contact resistance; (4) complicated product models: different application scenarios have different requirements for adhesive film adhesion and modulus, and manufacturers need to stock multiple models at the same time, increasing inventory and management costs.

[0004] Therefore, developing a conductive voltage-sensitive adhesive film with no small molecule residue, linearly tunable crosslinking degree, and the ability to cover multiple application needs with a single product has significant industrial application value.

[0005] The information disclosed in this background section is only for enhancing the understanding of the background technology of the present invention, and therefore may include information that does not constitute prior art. Summary of the Invention

[0006] To overcome the technical problems of existing conductive films, such as oxygen inhibition, difficulty in controlling pressure sensitivity, and small molecule residues, this invention provides a UV-tunable dual-curing conductive film, comprising component A, component B, and conductive filler. Component A comprises a functional acrylate copolymer prepared by solution polymerization of a monomer mixture, wherein the monomer mixture includes soft monomers, hard monomers, hydroxyl-containing monomers, epoxy-containing monomers, polymerizable benzophenone photoinitiators, silane coupling agents, and free radical polymerization initiators. Component B comprises one or a combination of a latent epoxy curing agent, a conductivity accelerator, a curing accelerator, and an anti-settling agent. This conductive film uses a pre-polymerized functional acrylate copolymer. The system contains no small molecule monomers. The UV curing process is a chain transfer crosslinking reaction between polymer chains. Free radicals are bound to the polymer chains, and oxygen cannot diffuse in and interfere with the reaction, thus fundamentally overcoming the oxygen inhibition defect of traditional UV curing technology. The chain transfer coupling reaction initiated by the polymerizable benzophenone photoinitiator can achieve controllable adjustment of the modulus by adjusting the UV exposure energy. The conductive film also has the advantages of no small molecule residue, excellent conductivity, and storage stability.

[0007] However, the present invention is not limited to the above aspects, but can be extended in various ways without departing from the technical spirit of the present invention.

[0008] This invention provides a UV-tunable dual-curing conductive adhesive film, comprising component A, component B, and conductive filler. Component A comprises a functional acrylate copolymer prepared by solution polymerization of a monomer mixture. The monomer mixture, by weight, comprises the following components: 50-60 parts of soft monomer 20-25 parts of hard monomer 1-5 parts of hydroxyl monomer 5-10 parts of epoxy group-containing monomers 0.5-1 part of silane coupling agent 1-2 parts of polymerizable benzophenone-based photoinitiator 0.2-1 part of free radical polymerization initiator Component B includes a functional filler; the functional filler, by weight, comprises the following components: 2-4 parts of latent epoxy curing agent Conductivity promoter 0.2-0.3 parts Curing accelerator 0.25-0.5 parts 1 part anti-settling agent The conductive filler has a content of 50-58 wt% in the total solids of components A and B of the conductive adhesive film.

[0009] Preferably, the soft monomer is one or more of 2-ethylhexyl acrylate and butyl acrylate; more preferably, the soft monomer is 2-ethylhexyl acrylate.

[0010] Preferably, the hard monomer is selected from one or more of methyl acrylate, ethyl acrylate, propyl acrylate, isobornyl acrylate, methyl methacrylate, ethyl methacrylate, isobornyl methacrylate, styrene, and acrylonitrile; more preferably, the hard monomer is selected from one or more of butyl acrylate, methyl acrylate, and ethyl acrylate.

[0011] Preferably, the hydroxyl-containing monomer is one or more selected from hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate, and hydroxybutyl methacrylate; more preferably, the hydroxyethyl acrylate is selected from hydroxyethyl acrylate.

[0012] Preferably, the epoxy-containing monomer is one or more selected from glycidyl methacrylate, glycidyl acrylate, 3,4-epoxycyclohexyl methacrylate and 4-hydroxybutyl acrylate glycidyl ether; more preferably, the epoxy-containing monomer is glycidyl methacrylate.

[0013] Preferably, the silane coupling agent is at least one selected from γ-methacryloxypropyltrimethoxysilane (KH-570), vinyltrimethoxysilane, vinyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane (KH-560), and γ-aminopropyltriethoxysilane (KH-550); more preferably, the silane coupling agent is γ-methacryloxypropyltrimethoxysilane.

[0014] Preferably, the polymerizable benzophenone photoinitiator is 4-acryloylhydroxybenzoic acid benzophenone.

[0015] Preferably, the free radical polymerization initiator is one of azobisisobutyronitrile, azobisisoheptanenitrile, and dimethyl azobisisobutyrate; more preferably, the free radical polymerization initiator is azobisisobutyronitrile.

[0016] Preferably, the latent epoxy curing agent is selected from one or more of 4,4'-diaminodiphenyl sulfone and 3,3'-diaminodiphenyl sulfone.

[0017] Preferably, the conductivity promoter is selected from one or more of succinic acid, glutaric acid, and succinic acid; and / or, Preferably, the curing accelerator is selected from one or a combination of feuron and diuron.

[0018] Preferably, the anti-settling agent is fumed silica.

[0019] Preferably, the conductive filler is flake-shaped silver powder.

[0020] Preferably, the flake silver powder has an average particle size of 1-10 μm, a diameter-to-thickness ratio of 10-50:1, and a specific surface area ≥1.0 m² / g.

[0021] A second aspect of the present invention provides a method for preparing the UV-tunable dual-curing conductive adhesive film, comprising the following steps: (1) Preparation of solution: By weight, soft monomer, hard monomer, hydroxyl-containing monomer, epoxy group-containing monomer, silane coupling agent, polymerizable benzophenone photoinitiator and free radical polymerization initiator are all mixed and stirred. After all the photoinitiator and the free radical polymerization initiator are dissolved, the solution is obtained. (2) Solution polymerization: By weight, add 30-100 parts of ethyl acetate solvent as a base agent to a reaction vessel equipped with a stirrer, thermometer, reflux condenser and dropping funnel, remove oxygen by nitrogen, and heat to 80-90℃; add 10% of the total amount of the solution obtained in step (1) to the reaction vessel, stir at medium speed, and keep the reaction at 80-90℃ for 20-40 minutes; then add the remaining 90% of the solution dropwise over 3-4 hours, and keep the temperature for 1-2 hours after the addition is complete to obtain the functional acrylate copolymer solution; (3) Preparation of conductive adhesive paste: Add latent epoxy curing agent, conductive accelerator, curing accelerator and anti-settling agent to the copolymer solution obtained in step (2), and then add conductive filler. The amount of conductive filler added is such that its content in the total solids of component A and component B of the conductive adhesive film reaches 50-58wt%. Mix and stir evenly to obtain conductive adhesive paste. (4) Coating and film formation: The conductive paste obtained in step (3) is coated on the release film, and the solvent is removed by drying in the drying tunnel to obtain an initial film with a thickness of 20-50 μm. (5) UV pre-crosslinking control: The initial adhesive film obtained in step (4) is irradiated with UV light at an energy of 20-500 mJ / cm². The crosslinking degree is controlled through chain transfer reaction to obtain a dual-cured conductive adhesive film with adjustable modulus and pressure sensitivity.

[0022] Preferably, the UV irradiation energy in step (5) is 20-500 mJ / cm², and the peel force of the film after irradiation with different energies at 25°C can be adjusted within the range of 0.15-10.23 N / cm at 180°.

[0023] Preferably, the functional acrylate copolymer described in step (2) has a weight-average molecular weight of 50,000-300,000 and a glass transition temperature of -34°C to 0°C.

[0024] A third aspect of the present invention provides an application of the UV-tunable dual-curing conductive film for electronic packaging.

[0025] Preferably, it is used to connect the flexible circuit board and the glass substrate.

[0026] Compared with the prior art, the beneficial effects of the present invention may include: 1. Completely solves the oxygen inhibition problem: Because the present invention uses pre-polymerized functional acrylate copolymers, there are no small molecule monomers in the system. The UV curing process is a chain transfer crosslinking reaction between polymer chains. Free radicals are bound to the polymer chains, and oxygen cannot diffuse into the reaction to interfere with it. This fundamentally overcomes the oxygen inhibition defect of traditional UV curing technology.

[0027] 2. Achieving controllable adjustment of film modulus: The crosslinking reaction of this invention is a chain transfer coupling reaction initiated by ABP. The modulus increases with increasing UV energy, while the pressure sensitivity (peel force) decreases with increasing UV energy. By adjusting the UV exposure energy, the peel force of the film can be continuously controlled within the range of 0.15-10.23 N / cm to meet the pressure sensitivity requirements of different application scenarios.

[0028] 3. No small molecule residue, safe and reliable: The system does not contain small molecule monomers or reactive diluents, avoiding the risk of unreacted substances migrating and contaminating precision components during subsequent use, making it particularly suitable for electronic assembly scenarios with high cleanliness requirements.

[0029] 4. Excellent conductivity: It uses large specific surface area flake silver powder with a silver powder content of 50-58wt%, which can obtain excellent volume resistivity and meet the conductivity requirements of precision electronic connections.

[0030] 5. Good storage stability: The combined use of latent curing agent DDS and accelerator U24M, along with the anti-settling effect of fumed silica, gives the film excellent storage stability at room temperature. Detailed Implementation

[0031] However, the present invention can be embodied in a variety of different forms and should not be construed as being limited to the embodiments described herein. Rather, these embodiments are provided as examples so that the invention will be thorough and complete, and will fully convey aspects and features of the invention to those skilled in the art. Therefore, unnecessary processes, steps, and techniques that would allow those skilled in the art to fully understand aspects and features of the invention are not described. The terms or words used in this specification and claims should not be construed as limited to their ordinary or dictionary meaning, but should be interpreted as meaning and concept consistent with the technical concept of the invention, based on the principle that the inventors can appropriately define the concepts of the terms to best describe the invention.

[0032] It is understood that the present invention can be modified in many alternative forms. It should be understood that the present invention is not limited to the specific forms disclosed, but is intended to cover all modifications, equivalents, and alternatives falling within the scope of the present invention.

[0033] Embodiments of the invention are described in more detail below. However, these embodiments are merely examples, and the invention is not limited thereto; rather, it is defined by the scope of the claims. The terminology used herein is for descriptive purposes only and is not intended to limit the invention.

[0034] As used herein, the terms “substantially,” “about,” and similar terms are used as approximate terms rather than as terms of degree, and are intended to take into account the inherent biases of measurements or calculations that would be recognized by one of ordinary skill in the art.

[0035] Furthermore, any numerical range described herein is intended to include all subranges containing the same numerical precision within the described range. For example, the range "1.0 to 10.0" is intended to include all subranges between the described minimum value of 1.0 and the described maximum value of 10.0 (and includes both the described minimum value of 1.0 and the described maximum value of 10.0), i.e., having a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0, such as 2.4 to 7.6. Any maximum numerical limit described herein is intended to include all lower numerical limits contained therein, while any minimum numerical limit described in this specification is intended to include all higher numerical limits contained therein. Therefore, the applicant reserves the right to amend this specification (including the claims) to expressly describe any subranges contained within the scope expressly described herein.

[0036] The following section will describe in detail a UV-tunable dual-curing conductive film of the present invention, its preparation method, and its application.

[0037] This invention provides a UV-tunable dual-curing conductive adhesive film, comprising component A, component B, and conductive filler. Component A comprises a functional acrylate copolymer prepared by solution polymerization of a monomer mixture. The monomer mixture, by weight, comprises the following components: 50-60 parts of soft monomer 20-25 parts of hard monomer 1-5 parts of hydroxyl monomer 5-10 parts of epoxy group-containing monomers 0.5-1 part of silane coupling agent 1-2 parts of polymerizable benzophenone-based photoinitiator 0.2-1 part of free radical polymerization initiator Component B includes a functional filler; the functional filler, by weight, comprises the following components: 2-4 parts of latent epoxy curing agent Conductivity promoter 0.2-0.3 parts Curing accelerator 0.25-0.5 parts 1 part anti-settling agent The conductive filler has a content of 50-58 wt% in the total solids of components A and B of the conductive adhesive film.

[0038] In an embodiment of the present invention, the soft monomer is 2-ethylhexyl acrylate.

[0039] In embodiments of the present invention, the hard monomer is selected from one or more of butyl acrylate, methyl acrylate, and ethyl acrylate.

[0040] In an embodiment of the present invention, the hydroxyl-containing monomer is hydroxyethyl acrylate.

[0041] In an embodiment of the present invention, the epoxy group-containing monomer is glycidyl methacrylate.

[0042] In an embodiment of the present invention, the silane coupling agent is γ-methacryloyloxypropyltrimethoxysilane.

[0043] In an embodiment of the present invention, the polymerizable benzophenone photoinitiator is 4-acryloylhydroxybenzoic acid benzophenone.

[0044] In an embodiment of the present invention, the free radical polymerization initiator is azobisisobutyronitrile.

[0045] In embodiments of the present invention, the latent epoxy curing agent is selected from one or a combination of 4,4'-diaminodiphenyl sulfone or 3,3'-diaminodiphenyl sulfone.

[0046] In embodiments of the present invention, the conductivity promoter is selected from one or more of succinic acid, glutaric acid, and succinic acid; In embodiments of the present invention, the curing accelerator is selected from one or a combination of feuron and diuron.

[0047] In an embodiment of the present invention, the anti-settling agent is fumed silica.

[0048] In an embodiment of the present invention, the conductive filler is flake-shaped silver powder.

[0049] In an embodiment of the present invention, the average particle size of the flake silver powder is 1-10 μm, the aspect ratio is 10-50:1, and the specific surface area is ≥1.0 m² / g.

[0050] Another aspect of the present invention provides a method for preparing the UV-tunable dual-curing conductive adhesive film, comprising the following steps: (1) Preparation of solution: By weight, soft monomer, hard monomer, hydroxyl-containing monomer, epoxy group-containing monomer, silane coupling agent, polymerizable benzophenone photoinitiator and free radical polymerization initiator are all mixed and stirred. After all the photoinitiator and the free radical polymerization initiator are dissolved, the solution is obtained. (2) Solution polymerization: By weight, add 30-100 parts of ethyl acetate solvent as a base agent to a reaction vessel equipped with a stirrer, thermometer, reflux condenser and dropping funnel, remove oxygen by nitrogen, and heat to 80-90℃; add 10% of the total amount of the solution obtained in step (1) to the reaction vessel, stir at medium speed, and keep the reaction at 80-90℃ for 20-40 minutes; then add the remaining 90% of the solution dropwise over 3-4 hours, and keep the temperature for 1-2 hours after the addition is complete to obtain the functional acrylate copolymer solution; (3) Preparation of conductive adhesive paste: Add latent epoxy curing agent, conductive accelerator, curing accelerator and anti-settling agent to the copolymer solution obtained in step (2), and then add conductive filler. The amount of conductive filler added is such that its content in the total solids of component A and component B of the conductive adhesive film reaches 50-58wt%. Mix and stir evenly to obtain conductive adhesive paste. (4) Coating and film formation: The conductive paste obtained in step (3) is coated on the release film, and the solvent is removed by drying in the drying tunnel to obtain an initial film with a thickness of 20-50 μm. (5) UV pre-crosslinking control: The initial adhesive film obtained in step (4) is irradiated with UV light at an energy of 20-500 mJ / cm². The crosslinking degree is controlled through chain transfer reaction to obtain a dual-cured conductive adhesive film with adjustable modulus and pressure sensitivity.

[0051] In an embodiment of the present invention, the UV irradiation energy in step (5) is 20-500 mJ / cm², and the 180° peel force of the film after irradiation with different energies at 25°C can be adjusted in the range of 0.15-10.23 N / cm.

[0052] In an embodiment of the present invention, the functional acrylate copolymer described in step (2) has a weight-average molecular weight of 50,000-300,000 and a glass transition temperature of -34°C to 0°C.

[0053] Another aspect of the present invention provides an application of the UV-tunable dual-curing conductive film for electronic packaging.

[0054] In an embodiment of the present invention, it is used to connect a flexible circuit board and a glass substrate.

[0055] To provide a clearer understanding of the technical content of this invention, the following embodiments are provided for detailed description. Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods. Unless otherwise specified, the raw materials involved in the following embodiments are all commercially available products that can be purchased from the market or prepared using existing methods. Examples 1-4

[0056] (1) Preparation of solution According to the components and their contents in Table 1, the following monomers and additives are added to the reaction vessel: soft monomers, hard monomers, hydroxyl-containing monomers, epoxy-containing monomers, silane coupling agents, polymerizable benzophenone photoinitiators and free radical polymerization initiators. All are mixed and stirred. After the polymerizable benzophenone photoinitiators and free radical polymerization initiators are completely dissolved, a solution is obtained. (2) Solution polymerization Add 60 parts of ethyl acetate solvent as a base in a three-necked flask equipped with a stirrer, thermometer, reflux condenser and dropping funnel, purge with nitrogen for 30 minutes to remove oxygen, and heat to 85°C. Add 10% of the total amount of the solution obtained in step (1) to the flask, stir at medium speed, and maintain the reaction at 85°C for 30 minutes. Then add the remaining 90% of the solution dropwise over 3.5 hours, and keep warm for 1.5 hours after the addition to obtain a functional acrylate copolymer solution. The weight average molecular weight of the copolymer in Example 1 was found to be 135,000. (3) Preparation of conductive paste Take 100 parts of the copolymer solution obtained in step (2) by dry weight of the copolymer, and add the following components according to the components and contents in Table 1: latent epoxy curing agent, conductive accelerator, curing accelerator, anti-settling agent and conductive filler. The conductive filler in Examples 1-4 is Metatel AA3462 flake silver powder, and the amount added is such that its content in the total solids of the adhesive film is 55wt%, 52wt%, 58wt% and 50wt%, respectively. Stir at 300rpm for 40 minutes in a high-speed disperser until uniformly mixed to obtain conductive adhesive paste. Table 1 (4) Coating to form a film The conductive adhesive was coated onto the PET release film and dried through a three-stage drying tunnel (60℃ / 2min, 80℃ / 2min, 100℃ / 2min) to remove the ethyl acetate solvent, resulting in an initial film with a thickness of 35μm. (5) UV pre-crosslinking regulation The initial adhesive film was irradiated with UV light of different energies (wavelengths including the UVC band). The irradiation energy was set to five levels: 20mJ / cm², 50mJ / cm², 100mJ / cm², 200mJ / cm², and 500mJ / cm². The test was conducted in accordance with GB / T 2792-2014 "Test Method for Peel Strength of Adhesive Tape" (Method 1: Peel Strength of Adhesive Tape to Stainless Steel at 180°). The test results are shown in Table 2.

[0057] Table 2 Results analysis: With increasing UV irradiation energy, the peel force of the film gradually decreased, and the pressure sensitivity showed a downward trend, indicating that the modulus and degree of crosslinking increased with increasing UV energy. By adjusting the UV energy, the pressure sensitivity and modulus of the film can be controlled within the range of 0.15-10.23 N / cm.

[0058] Performance testing The performance of the adhesive films obtained in Examples 1-4 was tested. Volume resistivity was tested according to ASTM D2739, "Standard Test Method for Volume Resistivity of Conductive Adhesives". Shear strength after thermosetting was tested according to GB / T 41852-2022, "Bending and Shear Test Methods for Bond Strength of Semiconductor Devices and MEMS Structures". Storage stability was tested using industry-standard methods, with viscosity change rate (25℃±2℃) measured using a rotational viscometer; generally, a change of less than 5% was considered negligible. The static observation method was used to visually determine whether sedimentation or delamination occurred in the conductive adhesive. The content of small molecule volatiles was tested according to GB 33372-2020, "Limits of Volatile Organic Compounds in Adhesives," to obtain the small molecule residue. The test results are shown in Table 3.

[0059] Table 3 Note: ① Thermosetting conditions: 175℃ / 60 minutes; ② Observe the viscosity change and silver powder sedimentation.

[0060] Comparative Example 1 30 parts epoxy resin, 20 parts acrylate monomer, 2 parts common photoinitiator, 3 parts DDS, and 250 parts flake silver powder were directly mixed and coated into a film. After UV curing, the performance was tested and it was found that: the surface was sticky, and there was obvious oxygen inhibition of polymerization; the degree of crosslinking had a non-linear relationship with UV energy, and curing was incomplete at low energy; small molecule volatiles were detected to precipitate after heat curing.

[0061] The test comparison between Examples 1-4 and Comparative Example 1 revealed that the conductive adhesives of Examples 1-4 overcome the oxygen inhibition defects of traditional UV curing technology, can achieve controllable adjustment of the film modulus, have no small molecule residues, and exhibit excellent conductivity and good storage stability.

[0062] The above-described technical features of the present invention and the technical features specifically described below (such as in the embodiments) can be combined with each other to form new or preferred technical solutions.

[0063] Finally, it should be emphasized that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A UV-tunable dual-curing conductive adhesive film, comprising component A, component B, and conductive filler, characterized in that, Component A comprises a functional acrylate copolymer prepared by solution polymerization of a monomer mixture, wherein the monomer mixture comprises soft monomers, hard monomers, hydroxyl-containing monomers, epoxy-containing monomers, polymerizable benzophenone photoinitiators, silane coupling agents, and free radical polymerization initiators; Component B comprises one or a combination of latent epoxy curing agents, conductive accelerators, curing accelerators, and anti-settling agents.

2. The UV-tunable dual-curing conductive adhesive film as described in claim 1, characterized in that, The monomer mixture comprises, by weight, the following components: 50-60 parts of soft monomer 20-25 parts of hard monomer 1-5 parts of hydroxyl monomer 5-10 parts of epoxy group-containing monomers 0.5-1 part of silane coupling agent 1-2 parts of polymerizable benzophenone-based photoinitiator 0.2-1 part of free radical polymerization initiator Component B includes a functional filler; the functional filler, by weight, comprises the following components: 2-4 parts of latent epoxy curing agent Conductivity promoter 0.2-0.3 parts Curing accelerator 0.25-0.5 parts 1 part anti-settling agent The conductive filler has a content of 50-58 wt% in the total solids of components A and B of the conductive adhesive film.

3. The UV-tunable dual-curing conductive adhesive film according to claim 1, characterized in that, The soft monomer is one or more of 2-ethylhexyl acrylate and butyl acrylate; The hard monomer is selected from one or more of methyl acrylate, ethyl acrylate, propyl acrylate, isobornyl acrylate, methyl methacrylate, ethyl methacrylate, isobornyl methacrylate, styrene, and acrylonitrile; The hydroxyl-containing monomer is one or more of hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate, and hydroxybutyl methacrylate. The epoxy group-containing monomer is one or more selected from glycidyl methacrylate, glycidyl acrylate, 3,4-epoxycyclohexyl methacrylate and 4-hydroxybutyl acrylate glycidyl ether. The silane coupling agent is at least one selected from γ-methacryloxypropyltrimethoxysilane (KH-570), vinyltrimethoxysilane, vinyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane (KH-560), and γ-aminopropyltriethoxysilane (KH-550). The polymerizable benzophenone photoinitiator is 4-acryloylhydroxybenzoic acid benzophenone; The free radical polymerization initiator is one of azobisisobutyronitrile, azobisisoheptanenitrile, and dimethyl azobisisobutyrate.

4. The UV-tunable modulus dual-curing conductive adhesive film according to claim 1, characterized in that, The latent epoxy curing agent is selected from one or a combination of 4,4'-diaminodiphenyl sulfone and 3,3'-diaminodiphenyl sulfone; The conductivity promoter is selected from one or more of succinic acid, glutaric acid and succinic acid; The curing accelerator is selected from one or a combination of feuron and diuron; The anti-settling agent is at least one of fumed silica organobentonite and organically modified montmorillonite; The conductive filler is flake-shaped silver powder.

5. The UV-tunable dual-curing conductive adhesive film according to claim 3, characterized in that, The flake-shaped silver powder has an average particle size of 1-10 μm, a diameter-to-thickness ratio of 10-50:1, and a specific surface area ≥1.0 m² / g.

6. A method for preparing a UV-tunable dual-curing conductive adhesive film according to any one of claims 1-4, characterized in that, Includes the following steps: (1) Preparation of solution: By weight, soft monomer, hard monomer, hydroxyl-containing monomer, epoxy group-containing monomer, silane coupling agent, polymerizable benzophenone photoinitiator and free radical polymerization initiator are all mixed and stirred. After all the photoinitiator and the free radical polymerization initiator are dissolved, the solution is obtained. (2) Solution polymerization: By weight, add 30-100 parts of ethyl acetate solvent as a base agent to a reaction vessel equipped with a stirrer, thermometer, reflux condenser and dropping funnel, remove oxygen by nitrogen, and heat to 80-90℃; add 10% of the total amount of the solution obtained in step (1) to the reaction vessel, stir at medium speed, and keep the reaction at 80-90℃ for 20-40 minutes; then add the remaining 90% of the solution dropwise over 3-4 hours, and keep the temperature for 1-2 hours after the addition is complete to obtain the functional acrylate copolymer solution; (3) Preparation of conductive adhesive paste: Add latent epoxy curing agent, conductive accelerator, curing accelerator and anti-settling agent to the copolymer solution obtained in step (2), and then add conductive filler. The amount of conductive filler added is such that its content in the total solids of component A and component B of the conductive adhesive film reaches 50-58wt%. Mix and stir evenly to obtain conductive adhesive paste. (4) Coating and film formation: The conductive paste obtained in step (3) is coated on the release film, and the solvent is removed by drying in the drying tunnel to obtain an initial film with a thickness of 20-50 μm. (5) UV pre-crosslinking control: The initial adhesive film obtained in step (4) is irradiated with UV light at an energy of 20-500 mJ / cm². The crosslinking degree is controlled through chain transfer reaction to obtain a dual-cured conductive adhesive film with adjustable modulus and pressure sensitivity.

7. The preparation method according to claim 6, characterized in that, The UV irradiation energy mentioned in step (5) is 20-500mJ / cm², and the peel force of the film after irradiation with different energies at 25°C can be adjusted within the range of 0.15-10.23N / cm at 180°.

8. The preparation method according to claim 6, characterized in that, The functional acrylate copolymer described in step (2) has a weight-average molecular weight of 50,000-300,000 and a glass transition temperature of -34°C to 0°C.

9. An application of a UV-tunable dual-curing conductive adhesive film according to any one of claims 1-5, characterized in that, Used for electronic packaging.

10. An application of a UV-tunable dual-curing conductive adhesive film according to any one of claims 1-5, characterized in that, Used to connect flexible circuit boards to glass substrates.

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