Ultraviolet curing organic silicon conductive adhesive and preparation method thereof

Abstract

The invention discloses an ultraviolet curing organic silicon conductive adhesive and a preparation method thereof, and relates to the technical field of conductive materials, the ultraviolet curing organic silicon conductive adhesive comprises the specific components of organic silicon matrix resin, a photosensitive curing agent, a conductive filler, a reactive diluent, a coupling agent and a thixotropic agent; the photosensitizer further comprises carborane cluster particles, a phosphazene silane nanocage, a sulfur-doped tungstate nanosheet, a potassium fluoride modified hollow graphene ball and an additive of a germanoxane photosensitizer. The material is prepared based on the materials. According to the preparation method, multiple functional additives are introduced into a traditional ultraviolet curing organic silicon conductive adhesive system, a multi-dimensional conductive path is constructed on the molecular and nanoscale, and the photocuring initiation efficiency and the interface stability are optimized, so that the prepared conductive adhesive not only realizes low resistivity, but also can be rapidly and deeply cured in an adhesive layer with relatively high thickness; and meanwhile, excellent damp-heat resistance and corrosion resistance are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of conductive materials, in particular to an ultraviolet light-cured organic silicon conductive adhesive and a preparation method thereof. Background Art

[0002] UV-curable silicone conductive adhesives, a key material for electronic component packaging, flexible circuit interconnection, and electromagnetic shielding, have garnered widespread attention in recent years in precision electronics manufacturing, optoelectronic packaging, and high-reliability interconnection. These adhesives typically consist of a silicone base resin, combined with a photosensitive curing agent, conductive filler, reactive diluent, coupling agent, and thixotropic agent. They rapidly cure under UV light, forming a cured layer with a certain degree of conductivity and bond strength. These adhesives effectively meet functional requirements for high-speed signal transmission, circuit connection fixation, and anti-static properties.

[0003] Although existing UV-curable silicone conductive adhesives have certain electrical conductivity and light-curing properties, they still have the following major shortcomings: Poor conductive network stability: Traditional systems mostly use common conductive fillers such as silver powder and carbon black. Due to poor filler dispersion and insufficient interfacial bonding, the electron migration channel is easily broken, and the volume resistivity fluctuates greatly over time and environmental conditions, making it difficult to maintain stable conductive performance over the long term. Insufficient curing depth and environmental adaptability: Affected by the absorption efficiency of the photoinitiator and the shading effect of the conductive filler, the curing depth of the existing colloid is limited, and the thick glue layer is not completely cured. At the same time, the performance is significantly degraded in harsh environments such as high humidity and salt spray, which limits its long-term application in high-end packaging and outdoor equipment. Summary of the Invention

[0004] In view of the deficiencies in the prior art, the present invention provides a UV-curable organic silicone conductive adhesive and a preparation method thereof to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions: The present invention provides a UV-curable organic silicon conductive adhesive comprising the following specific components: Silicone matrix resin, photosensitive curing agent, conductive filler, reactive diluent, coupling agent and thixotropic agent; The organic silicon conductive adhesive further comprises additives, which specifically include: Carborane cluster particles, phosphazene silane nanocages, sulfur-doped tungstate nanosheets, potassium fluoride-modified hollow graphene spheres, and germanium oxide photosensitizers.

[0006] To further optimize this technical solution, the mass fractions of the specific components are as follows: 40-60 parts of silicone matrix resin; Photosensitive curing agent is 3-8 parts; Conductive filler is 20-40 parts; Reactive diluent is 5-15 parts; The coupling agent is 0.5-3 parts; The thixotropic agent is 0.1-2 parts.

[0007] To further optimize this technical solution, the specific components include: The organic silicon matrix resin is mainly composed of organic silicon polymers containing methyl, phenyl or fluoro substituents, and polydimethylsiloxane PDMS, vinyl terminated silicone oil, and phenyl modified silicone resin are selected; The photosensitive curing agent includes an α-hydroxy ketone photoinitiator and a diphenylphosphine oxide photoinitiator. The α-hydroxy ketone photoinitiator is selected from phenyl dimethyl ethyl ketone and 2-hydroxy-2-methyl-1-phenyl acetone, and the diphenylphosphine oxide photoinitiator is diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide. Conductive fillers include silver powder, silver-plated copper powder, and graphene nanosheets; The reactive diluent is a low-viscosity acrylic monomer including trimethylolpropane triacrylate TMPTA and dihydroxypropyl acrylate; The coupling agent is a silane coupling agent, including γ-aminopropyltriethoxysilane KH-550 and methacryloxypropyltrimethoxysilane KH-570; The thixotropic agent is modified fumed silica and polyamide wax powder.

[0008] To further optimize this technical solution, the mass fractions of the additives are as follows: 2-5 parts of carborene cluster particles; 1-3 parts of phosphazene silane nanocage; The sulfur-doped tungstate nanosheets are 1-4 parts; The potassium fluoride modified hollow graphene spheres are 2-6 parts; The amount of the germanium oxane photosensitizer is 0.5-2 parts.

[0009] Further optimizing the technical solution, the carbon boron olefin cluster particles are carbon-boron-hydrogen ternary compounds with a dodecahedral cage structure, and the molecular formula is B 12 C4H 12 By modifying the surface with hydroxyl or organosilane groups to enhance its compatibility and chemical bonding with the organosilicon matrix, the carbon borane cluster particles construct an electron tunneling conductive network in the conductive adhesive to provide excellent electron mobility and thermal stability.

[0010] Further optimizing the technical solution, the phosphazene silane nanocage is composed of a cyclic polyphosphazene skeleton unit [(NPCl2)3] covalently bonded to a silane group, and has a particle size of 1-3 nm; This nanocage has a phosphorus-nitrogen main chain structure and peripheral silane active groups, which are used to achieve covalent cross-linking in the silicone system to improve the material's flame retardancy, resistance to ion migration and long-term electrical insulation stability.

[0011] The present technical solution is further optimized. The sulfur-doped tungstate nanosheets are formed by partially replacing sulfur elements in the layered tungstate lattice to form a WSO mixed lattice structure with a thickness of 5-10 nm, and the surface is functionalized with aminosilane or hydroxysilane.

[0012] The technical solution is further optimized. The potassium fluoride-modified hollow graphene spheres have a hollow structure with a diameter of 200-500 nm, and are evenly loaded with potassium fluoride nanocrystals on the surface, and the graphene surface is functionalized through ionic bonds. The potassium fluoride-modified hollow graphene spheres construct electron / ion cooperative conductive channels with low interfacial impedance in the conductive glue colloid and alleviate the volume shrinkage stress during the colloid curing process.

[0013] To further optimize this technical solution, the germanoxane photosensitizer is an organic oxane derivative containing germanium, with a molecular formula of Ge(OCH3)4 derivative structure, which is used to synergize with the photosensitive curing agent to improve the ultraviolet light curing rate and crosslinking density.

[0014] A method for preparing a UV-curable silicone conductive adhesive is based on the above-mentioned silicone conductive adhesive and includes the following specific steps: S1. Pre-mixing of silicone matrix resin; S2, adding a photosensitive curing agent and a germanium oxide photosensitizer and uniformly dispersing them; S3, synergistic dispersion of conductive fillers and potassium fluoride modified hollow graphene spheres; S4. Add reactive diluent and coupling agent to improve system viscosity and interface bonding; S5, synergistic introduction of carborane cluster microparticles, phosphazene silane nanocages, and sulfur-doped tungstate nanosheets; S6. Regulating the thixotropic agent and performing vacuum degassing to obtain the final UV-curable silicone conductive adhesive.

[0015] Compared with the prior art, the present invention provides a UV-curable silicone conductive adhesive and a preparation method thereof, which has the following beneficial effects: This UV-curable silicone conductive adhesive and its preparation method introduce multiple functional additives into a traditional UV-curable silicone conductive adhesive system, construct multidimensional conductive pathways at the molecular and nanoscale, and optimize the light-curing initiation efficiency and interface stability. The prepared conductive adhesive not only achieves low resistivity, but also can quickly and deeply cure in thicker adhesive layers, while also having excellent moisture, heat, and corrosion resistance. This significantly improves the reliability and service life of the conductive adhesive in complex environments, broadening its application in high-end electronic packaging, flexible device interconnection, and electronic component protection under harsh conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 This is a schematic diagram of the composition of a UV-curable silicone conductive adhesive proposed in the present invention; Figure 2 The present invention provides a flow chart of a method for preparing a UV-curable organic silicone conductive adhesive. DETAILED DESCRIPTION

[0018] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0019] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0020] Secondly, the term "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in various places throughout this specification does not necessarily refer to the same embodiment, nor does it constitute a separate or selective embodiment that is mutually exclusive with other embodiments.

[0021] Example 1: Reference Figure 1 , which is the first embodiment of the present invention, provides a UV-curable silicone conductive adhesive, including the following specific components: Silicone base resin, photosensitive curing agent, conductive filler, reactive diluent, coupling agent and thixotropic agent.

[0022] In this embodiment, the specific components include: The silicone matrix resin is primarily composed of silicone polymers containing methyl, phenyl, or fluoro substituents, specifically glycidyl methacrylate-terminated polydimethylsiloxane (75%) and vinyl-terminated polydimethylsiloxane (25%). The silicone matrix resin provides the basic three-dimensional network structure and flexible backbone for the conductive adhesive, exhibiting excellent high- and low-temperature resistance, UV aging resistance, and dielectric stability. Its unique Si-O-Si backbone structure imparts excellent weatherability and electrical insulation properties, while also providing a dispersion medium for the conductive particles. The matrix's high optical transparency ensures effective UV light penetration into the system, enabling rapid and uniform curing. Compared to epoxy and acrylic resins, the silicone matrix offers high-temperature resistance from -60°C to 250°C, strong adhesion, and excellent flexibility, making it suitable for electronic component packaging environments subject to high thermal shock and mechanical stress requirements.

[0023] Photosensitive curing agents include α-hydroxyketone photoinitiators and diphenylphosphine oxide photoinitiators. The α-hydroxyketone photoinitiator is 2-hydroxy-2-methyl-1-phenylpropanone (60%), and the diphenylphosphine oxide photoinitiator is diphenyl (2,4,6-trimethylbenzoyl)phosphine oxide (40%). Under ultraviolet light, photosensitive curing agents rapidly decompose to generate free radicals or cations, which trigger the crosslinking reaction of the acrylic functional groups in the silicone system, achieving rapid curing. The photosensitive curing agent determines the curing rate, cure depth, and crosslink density of the conductive adhesive, significantly affecting production efficiency and final mechanical properties.

[0024] The conductive filler comprises ultrafine silver flakes (80%) with a particle size of 0.5-2μm, silver-coated copper powder (15%), and graphene nanosheets (5%). Conductive fillers form conductive pathways within the cured colloid, enabling electron transport and are key components in achieving low volume resistivity in conductive adhesives. Appropriate particle size distribution and surface modification can optimize the colloid's thixotropy, printability, and long-term conductive stability.

[0025] The reactive diluent is a low-viscosity acrylic monomer, including trimethylolpropane triacrylate (TMPTA) (65%) and dihydroxypropyl acrylate (35%). The diluent reduces the initial viscosity of the system, improving coating, dispensing, and permeability, and enhancing the ability to fill fine gaps. Furthermore, the reactive diluent monomer participates in the photocuring crosslinking reaction, preventing the release of small volatile molecules in the system and improving the stability of the cured material.

[0026] The coupling agent is a silane coupling agent, including γ-aminopropyltriethoxysilane KH-550 (60%) and methacryloyloxypropyltrimethoxysilane KH-570 (40%). The coupling agent can form an organic-inorganic interface bridge on the surface of the conductive filler, improving the filler's dispersion and bonding strength in the silicone matrix, and reducing interfacial shedding and resistance increase.

[0027] The thixotropic agent is a mixture of modified fumed silica (80%) with a particle size of 7-12 nm and polyamide wax micropowder (20%). The thixotropic agent is used to adjust the rheological properties of the system, giving the colloid good thixotropy and anti-sagging properties.

[0028] In this embodiment, the mass fractions of the specific components are as follows: The silicone matrix resin is 40 parts; The photosensitive curing agent is 3 parts; The conductive filler is 20 parts; Reactive diluent is 5 parts; The coupling agent is 0.5 parts; The thixotropic agent is 0.1 parts.

[0029] The organic silicon conductive adhesive further comprises additives, which specifically include: Carborane cluster particles, phosphazene silane nanocages, sulfur-doped tungstate nanosheets, potassium fluoride-modified hollow graphene spheres, and germanium oxide photosensitizers.

[0030] In this embodiment, the carbon boron olefin cluster particles are carbon-boron-hydrogen ternary compounds with a dodecahedral cage structure, and the molecular formula is B 12 C4H 12 Modified with surface hydroxyl or organosilane groups to enhance compatibility and chemical bonding with the silicone matrix, the carbon borophene cluster particles construct an electron tunneling conductive network within the conductive adhesive, significantly reducing interfacial resistance and providing excellent electron mobility and thermal stability. Furthermore, their three-dimensional cage structure offers excellent resistance to high temperatures and radiation, enhancing the long-term stability of the colloid.

[0031] Compared with existing carbon-based fillers such as carbon nanotubes or graphene, the multi-center electronic structure of carbon borophene clusters can achieve the same level or even better conductivity at a low filling rate, and also has thermal neutron absorption properties.

[0032] In this embodiment, the phosphazene silane nanocage is composed of a cyclic polyphosphazene backbone unit [(NPCl2)3] covalently bonded to a silane group, with a particle size of 1-3 nm and a molecular formula of [(NPCl2)3(SiR3)6]. This nanocage, with a phosphorus-nitrogen backbone structure and peripheral silane reactive groups, is used to achieve covalent crosslinking within an organosilicon system, enhancing the material's flame retardancy, resistance to ion migration, and long-term electrical insulation stability. Its phosphorus-nitrogen backbone provides excellent flame retardancy and resistance to ion migration, while the silane groups covalently bond to the organosilicon matrix, forming a highly crosslinked three-dimensional network structure that enhances the colloidal mechanical strength and electrochemical corrosion resistance.

[0033] Unlike conventional flame retardants or coupling agents, this material has multiple functions of flame retardancy, anti-electrochemical migration and enhanced cross-linking network. It can significantly improve the long-term reliability of conductive adhesives in humid and high-voltage environments, and provide innovative solutions for the application of electronic components in high-voltage DC fields.

[0034] In this example, the sulfur-doped tungstate nanosheets, formed by partially replacing sulfur in a layered tungstate lattice to form a WSO hybrid lattice structure, are 5-10 nm thick and surface-functionalized with aminosilane or hydroxysilane. These nanosheets form an auxiliary electron conduction network within the conductive adhesive. Their strong light absorption and energy transfer properties also enhance UV curing speed and depth, addressing the problem of fast surface curing and slow curing in deeper layers of thick coatings.

[0035] Unlike traditional photoinitiators, this material has both optical catalysis and conductive additive functions, which can reduce the amount of photoinitiator used, reduce migration residues, and improve curing uniformity and conductivity. It is a new dual-functional material that is rarely used in the conductive adhesive industry.

[0036] In this example, the potassium fluoride-modified hollow graphene spheres are hollow, 200-500 nm in diameter, and uniformly loaded with potassium fluoride (KF) nanocrystals. This functionalization is achieved through ionic bonding. The potassium fluoride-modified hollow graphene spheres create low-interface-impedance electron / ion cooperative conductive pathways within the conductive adhesive and mitigate volume shrinkage stress during the curing process. This additive creates low-interface-impedance conductive pathways within the colloid and modulates electron mobility through KF ions, improving the transmission stability of weak current signals. Furthermore, the hollow structure mitigates shrinkage stress during curing and reduces interfacial cracking.

[0037] Traditional graphene fillers only provide a single conductive pathway and cannot effectively improve the stability of ion migration. However, potassium fluoride-modified hollow graphene improves low-current conductivity through an electron / ion cooperative transport mechanism, and has obvious advantages in low-power fields such as flexible electronic devices and sensors.

[0038] In this embodiment, the germanium-containing organooxane photosensitizer is a germanium-containing organooxane derivative with a molecular formula of Ge(OCH3)4. It is designed to synergize with the photosensitive curing agent to increase the UV curing rate and crosslink density. This component acts as an auxiliary photosensitizer, absorbing UV light and generating active free radicals to increase the curing rate and crosslink density.

[0039] Unlike conventional amine or ketone co-initiators, germanium-based compounds have higher light absorption coefficients and no yellowing. They are chemically stable and do not produce colored byproducts, thus maintaining the transparency and stable electrical properties of the conductive adhesive after curing.

[0040] In this embodiment, the mass fractions of the additives are as follows: The carborene cluster particles are 2 parts; 1 part of phosphazene silane nanocage; Sulfur-doped tungstate nanosheets are 1 part; Potassium fluoride modified hollow graphene spheres are 2 parts; The amount of the germanium oxane photosensitizer is 0.5 parts.

[0041] Example 2: Reference Figure 2 , which is the second embodiment of the present invention, provides a method for preparing a UV-curable organic silicone conductive adhesive, which is prepared based on the organic silicone conductive adhesive described in Example 1 and includes the following specific steps: S1. Pre-mixing of silicone matrix resin.

[0042] Add the pre-weighed silicone matrix resin to a vacuum stirred vessel. Under inert gas, maintain the temperature within a suitable range (e.g., 40-60°C) and perform preliminary stirring at a medium-low speed for approximately 30-60 minutes. During this time, use a filter to remove any mechanical impurities in the resin, and vacuum extraction to remove dissolved gases to obtain a homogeneous, pure resin matrix.

[0043] By stirring and heating the silicone matrix resin for premixing, the resin molecular chain is fully extended, while the tiny bubbles and impurities in the system are reduced, creating a stable matrix environment for the uniform dispersion of subsequent fillers and additives.

[0044] S2. Add photosensitive curing agent and germanium oxide photosensitivity enhancer and disperse them evenly.

[0045] To the homogeneous resin matrix obtained in step S1, a pre-measured photosensitive curing agent is slowly added and stirred until uniformly distributed. Subsequently, a germanium oxane photosensitizer is introduced. A high-speed dispersing device is used to disperse and stir the mixture at an appropriate speed to ensure that both photosensitive components are fully dissolved and distributed between the matrix molecular chains. During this process, the system temperature is controlled to not exceed 60°C to prevent premature decomposition of the photosensitizer. After stirring for 30 minutes, an intermediate system with high photosensitivity is formed.

[0046] By synergistically introducing a photosensitive curing agent and a germanium oxane photosensitizer, the photoinitiation band can be broadened and the free radical generation rate can be increased, thereby shortening the curing time and reducing uneven curing.

[0047] S3, synergistic dispersion of conductive fillers and potassium fluoride modified hollow graphene spheres.

[0048] The weighed conductive filler is slowly added to the product from step S2, and initially dispersed under shear for 10-15 minutes. A predetermined amount of potassium fluoride-modified hollow graphene spheres is then added, and ultrasonic dispersion combined with mechanical stirring is used to evenly distribute the two conductive fillers. Controlled speed and vacuum degassing are used to prevent localized agglomeration, ultimately forming a semi-finished conductive adhesive with a three-dimensional interconnected network, ensuring stable conductive properties in the subsequent system.

[0049] Conventional conductive fillers provide the main pathway for electronic conduction, while potassium fluoride-modified hollow graphene spheres supplement the conductive network through ion-electron dual conduction channels, effectively reducing the interface contact resistance.

[0050] S4. Add reactive diluent and coupling agent to improve system viscosity and interface bonding.

[0051] Transfer the product from step S3 to a thermostatic stirring device and slowly add a pre-measured amount of reactive diluent, controlling the addition rate to avoid a sudden change in the system's viscosity. After stirring evenly, add the coupling agent, which will react with the matrix and filler surfaces using its multifunctional properties. Maintain stirring at below 60°C for 30 minutes to achieve a moderate viscosity and enhance interfacial bonding, resulting in a colloidal semi-finished product with good fluidity.

[0052] Reactive diluents are used to reduce system viscosity, facilitating subsequent coating and potting operations. They also participate in the cross-linking reaction after curing, eliminating the introduction of low-molecular-weight residues. Coupling agents improve interfacial bonding and overall mechanical strength by forming a chemical bridge between the inorganic filler and the organic matrix.

[0053] S5. Synergistically introduce carbon boron nitrile cluster particles, phosphazene silane nanocages, and sulfur-doped tungstate nanosheets.

[0054] In step S4, the colloidal system is slowly added with weighed additives, starting with the carborane cluster microparticles, which are dispersed at a moderate speed to form a preliminary conductive tunneling network. Phosphazene silane nanocages are then added, using high shear dispersion to ensure full contact with the matrix resin and achieve multi-point chemical bonding. Finally, sulfur-doped tungstate nanosheets are added, and ultrasonic synergistic stirring is used to enhance the dispersion of the photosensitizer. The entire process is carried out under an inert atmosphere to prevent oxidation and aggregation, resulting in a highly stable and sensitive colloidal premix.

[0055] Carbon boron olefin cluster particles establish quantum tunneling conductive pathways; phosphazene silane nanocages improve three-dimensional crosslinking density and flame retardancy; sulfur-doped tungstate nanosheets enhance photosensitivity and optimize curing depth.

[0056] S6. Regulating the thixotropic agent and performing vacuum degassing to obtain the final UV-curable silicone conductive adhesive.

[0057] In step S5, an appropriate amount of thixotropic agent is added to the system, and medium-speed stirring is used to fully disperse and adjust the system's thixotropic properties, achieving a balanced state where the material does not settle during storage and flows easily during application. Finally, a degassing treatment is performed by gradually reducing the pressure under a vacuum environment to ensure that no visible bubbles are present within the colloid. After filtration and impurity removal, a uniform, stable, and ready-to-use UV-curable silicone conductive adhesive is obtained.

[0058] Thixotropic agents adjust the rheological properties of the colloid, preventing filler sedimentation and improving adhesive consistency. Vacuum degassing removes microbubbles introduced during the preparation process, preventing void defects after curing, thereby ensuring the density and reliability of the finished conductive adhesive.

[0059] At the same time, a number of performance tests were performed on the final silicone conductive adhesive. The test contents and results are shown in Table 1.

[0060] Table 1

[0061] Combined with the test content and results given in Table 1, the following summary is made: 1. Electrical performance test (1) Volume resistivity test The volume resistivity of the sample after curing was measured using the four-probe method at 25°C and atmospheric pressure. The test result was 1.2×10 -3 Ω·cm, indicating that the colloid has extremely low volume resistivity and can form a stable electron transmission path, making it suitable for packaging and interconnection applications requiring high conductivity.

[0062] (2) Surface resistivity test The surface resistivity was measured using a high resistance meter at 25°C and 60% relative humidity, and the result was 5.6×10^2 Ω / sq, indicating that a uniform conductive network was formed on the surface of the cured conductive adhesive, which can meet the application requirements of high-frequency signal transmission and electrostatic discharge.

[0063] 2. Mechanical properties test (1) Shear strength test The samples were tested for shear strength at room temperature using a standard tensile testing machine. A load-to-failure test was conducted 24 hours after curing, yielding a strength of 3.5 MPa. This demonstrates the high adhesion of the conductive adhesive, enabling effective structural fixation and reliable connections between electronic components.

[0064] (2) Elongation test The sample was tensile tested at a tensile speed of 50 mm / min, and the measured elongation was 45%, indicating that the colloid has good flexibility and can maintain structural integrity without brittle cracking under temperature changes and mechanical vibration environments.

[0065] 3. Light curing performance test (1) Curing time test The colloid was exposed to UV light with a wavelength of 365 nm and a light intensity of 100 mW / cm². The time required for complete curing was recorded, and the result was 15 seconds. This shows that the material has fast response characteristics and can significantly improve production efficiency.

[0066] (2) Curing depth test Under the same UV conditions, the cured sample was sliced ​​and measured after 30 seconds of irradiation, and the curing depth reached 4.8 mm, indicating that the colloid has good light transmittance and photoinitiation efficiency, and can meet the curing requirements of thicker adhesive layers.

[0067] 4. Environmental stability test (1) Moisture and heat resistance test: The cured sample was placed in an environment of 85°C and 85% relative humidity for 168 hours. The resistance change rate before and after the test was less than 2%, indicating that the conductive adhesive has excellent stability in high humidity and heat environments and can be used in high-temperature and high-humidity electronic devices.

[0068] (2) Salt spray corrosion resistance test The cured sample was exposed to a 5% NaCl solution salt spray test chamber for 48 hours, and there was no corrosion or blistering on the surface, proving that the conductive adhesive has excellent anti-corrosion properties and can be used for long-term packaging and interconnection in harsh environments.

[0069] In summary, this test fully verified the comprehensive performance advantages of the prepared UV-curable silicone conductive adhesive in terms of electrical properties, mechanical properties, light curing efficiency and environmental adaptability: Excellent conductive properties: volume resistivity as low as 10 -3 The surface resistivity is on the order of Ω·cm and is uniform, ensuring stable and fast electronic signal transmission. It is suitable for precision circuit packaging and flexible interconnect devices.

[0070] Strong mechanical bonding and good flexibility: With 3.5 MPa shear strength and 45% elongation, it can resist stress changes caused by mechanical shock and thermal expansion and contraction, ensuring long-term stability of the device.

[0071] Fast and deep curing: Full curing is achieved within 15 seconds, with a curing depth of up to 4.8 mm, significantly improving production efficiency and making it suitable for automated production lines and thick glue applications.

[0072] Excellent environmental stability: High performance retention rate in hot and humid cycling and salt spray corrosion environments, can be used for a long time under extreme working conditions, and improve the life and reliability of electronic packaging.

[0073] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A UV-curable silicone conductive adhesive, characterized in that: It includes the following specific components: Silicone matrix resin, photosensitive curing agent, conductive filler, reactive diluent, coupling agent and thixotropic agent; The UV-curable silicone conductive adhesive further includes additives, which specifically include: Carborane cluster particles, phosphazene silane nanocages, sulfur-doped tungstate nanosheets, potassium fluoride-modified hollow graphene spheres, and germanium oxide photosensitizers.

2. The UV-curable silicone conductive adhesive according to claim 1, characterized in that: The mass fractions of the specific components are as follows: The silicone matrix resin is 40-60 parts; Photosensitive curing agent is 3-8 parts; Conductive filler is 20-40 parts; Reactive diluent is 5-15 parts; The coupling agent is 0.5-3 parts; The thixotropic agent is 0.1-2 parts.

3. The UV-curable silicone conductive adhesive according to claim 1, characterized in that: Among the specific components: The organic silicon matrix resin is mainly composed of organic silicon polymers containing methyl, phenyl or fluoro substituents, and polydimethylsiloxane PDMS, vinyl terminated silicone oil, and phenyl modified silicone resin are selected; The photosensitive curing agent includes an α-hydroxy ketone photoinitiator and a diphenylphosphine oxide photoinitiator. The α-hydroxy ketone photoinitiator is selected from phenyl dimethyl ethyl ketone and 2-hydroxy-2-methyl-1-phenyl acetone, and the diphenylphosphine oxide photoinitiator is diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide. Conductive fillers include silver powder, silver-plated copper powder, and graphene nanosheets; The reactive diluent is a low-viscosity acrylic monomer including trimethylolpropane triacrylate TMPTA and dihydroxypropyl acrylate; The coupling agent is a silane coupling agent, including γ-aminopropyltriethoxysilane KH-550 and methacryloxypropyltrimethoxysilane KH-570; The thixotropic agent is modified fumed silica and polyamide wax powder.

4. The UV-curable silicone conductive adhesive according to claim 1, characterized in that: The mass fractions of the additives are as follows: 2-5 parts of carborene cluster particles; 1-3 parts of phosphazene silane nanocage; The sulfur-doped tungstate nanosheets are 1-4 parts; The potassium fluoride modified hollow graphene spheres are 2-6 parts; The amount of the germanium oxane photosensitizer is 0.5-2 parts.

5. The UV-curable silicone conductive adhesive according to claim 1, characterized in that: The carbon boron olefin cluster particles are carbon-boron-hydrogen ternary compounds with a dodecahedral cage structure, and the molecular formula is B 12 C4H 12 By modifying the surface with hydroxyl or organosilane groups to enhance its compatibility and chemical bonding with the organosilicon matrix, the carbon borane cluster particles construct an electron tunneling conductive network in the conductive adhesive to provide excellent electron mobility and thermal stability.

6. The UV-curable silicone conductive adhesive according to claim 1, characterized in that: The phosphazene silane nanocage is composed of a cyclic polyphosphazene skeleton unit [(NPCl2)3] covalently bonded to a silane group, and has a particle size of 1-3 nm; The nanocage has a phosphorus-nitrogen main chain structure and peripheral silane active groups, and is used to achieve covalent cross-linking in an organosilicon system, thereby improving the flame retardancy, resistance to ion migration and long-term electrical insulation stability of the material.

7. The UV-curable silicone conductive adhesive according to claim 1, characterized in that: The sulfur-doped tungstate nanosheets are formed by partially replacing sulfur elements in a layered tungstate lattice to form a WSO mixed lattice structure, have a thickness of 5-10 nm, and are surface-functionalized with aminosilane or hydroxysilane.

8. The UV-curable silicone conductive adhesive according to claim 1, characterized in that: The potassium fluoride-modified hollow graphene sphere has a hollow structure with a diameter of 200-500 nm, and the surface is evenly loaded with potassium fluoride nanocrystals, and the graphene surface is functionalized through ionic bonds; Potassium fluoride-modified hollow graphene spheres construct electron / ion cooperative conductive channels with low interfacial impedance in conductive colloids and alleviate the volume shrinkage stress during the colloid curing process.

9. The UV-curable silicone conductive adhesive according to claim 1, characterized in that: The germanium oxane photosensitizer is an organic oxane derivative containing germanium element, and its molecular formula is Ge(OCH3)4 derivative structure, which is used to cooperate with the photosensitive curing agent to improve the ultraviolet light curing rate and crosslinking density.

10. A method for preparing a UV-curable silicone conductive adhesive, comprising preparing the silicone conductive adhesive according to any one of claims 1 to 9, wherein: The specific steps include: S1. Pre-mixing of silicone matrix resin; S2, adding a photosensitive curing agent and a germanium oxide photosensitizer and uniformly dispersing them; S3, synergistic dispersion of conductive fillers and potassium fluoride modified hollow graphene spheres; S4. Add reactive diluent and coupling agent to improve system viscosity and interface bonding; S5, synergistic introduction of carborane cluster microparticles, phosphazene silane nanocages, and sulfur-doped tungstate nanosheets; S6. Regulating the thixotropic agent and performing vacuum degassing to obtain the final UV-curable silicone conductive adhesive.

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