A low-bismuth tin glue composite conductive adhesive material, a preparation method and application thereof

Abstract

The application discloses a low-bismuth tin glue composite conductive bonding material and a preparation method and application thereof, and belongs to the technical field of conductive bonding materials, and comprises the following raw materials in parts by weight: low-bismuth tin-based microalloy particles 55-82 parts, conductive reinforcing fillers 3-25 parts, thermosetting soldering resin 8-28 parts, latent curing agent 0.3-6 parts, reactive activator 0.2-5 parts, glass / metal amphiphilic coupling agent 0.1-4 parts, ion capturing agent 0.1-5 parts, corrosion inhibitor 0.05-3 parts, toughening agent 0.5-8 parts and defoaming agent 0.05-3 parts. The low-bismuth tin-based microalloy particles are used to replace high-Bi solder, and through a conductive filler redundant network, a same-temperature window soldering resin and an amphiphilic coupling system, 160 DEG C / 15 min rapid curing is realized, so that the glass metallization connection has high pulling force (more than 50 N) and low resistance change rate (less than 10%), and supports automatic mass production and online detection.

Description

Technical Field

[0001] This invention belongs to the field of conductive adhesive materials technology, and particularly relates to a low bismuth-tin adhesive composite conductive adhesive material, its preparation method and application. Background Technology

[0002] Glass metallization is widely used in automotive rear window heating wire terminals, window antenna terminals, heated lenses, transparent conductive glass, dimming glass, electrochromic glass, photovoltaic glass busbars, glass-based sensors, and edge electrodes of display glass. These connection structures share common characteristics: the substrate is high-modulus brittle glass, the functional layer is typically a silver paste sintered layer, a transparent conductive oxide layer, or a thin metal plating, and the connected object is usually copper, tin-plated copper, nickel-plated copper, stainless steel, nickel sheet, or flexible circuit board. During glass metallization, there are differences in thermal expansion coefficients, surface energy, and interfacial chemistry between the glass substrate and the metal tongue. The thermal expansion coefficient of glass is usually lower than that of the metal terminal, and the adhesive layer bears shear stress and peel stress during temperature cycling. The silver paste or transparent conductive oxide layer has a limited thickness; excessive local stress can lead to plating peeling, conductive layer delamination, or the propagation of microcracks at the glass edge.

[0003] The bonding materials used for glass metallization typically include solder paste and conductive adhesive. Traditional solder paste primarily uses metal soldering as the bonding mechanism. Low-temperature solder paste often employs a Sn-Bi system to lower the melting point. High-Bi solder can form a metal connection at lower temperatures, but high Bi content increases brittleness, reduces toughness and impact resistance after thermal cycling, and may lead to crack propagation under long-term loads or temperature fluctuations. For glass coating bonding, the hard and brittle characteristics of high-Bi systems easily concentrate stress at the coating interface. Traditional conductive adhesives form a contact conductive network in resin using silver powder or silver-coated copper powder. This system can cure at low temperatures and form a certain bond strength with glass or metal. However, the conductive path mainly relies on the mechanical contact between fillers. Moisture absorption, resin relaxation, interface corrosion, and filler oxidation can lead to increased contact resistance. Furthermore, while the initial pull-out performance of ordinary conductive adhesives may be acceptable, the risk of resistance drift is high under high temperature and humidity, salt spray, and long-term energization conditions. In addition, the combination of solder paste and conductive adhesive can take advantage of the metallic conductivity of solder and the adhesive buffering properties of resin at the same time. However, simple mixing usually cannot meet the application requirements. Resin may block solder wetting, oxides on the solder surface may cause discontinuity of metal bridges, and migratable ions in ordinary flux may cause electrochemical migration under humid heat and electric conditions. A single coupling agent may not be able to act on glass hydroxyl groups, metal oxide layers and silver paste coatings at the same time.

[0004] Currently, glass cleaning agents, salt spray, damp heat, and water impact conditions place demands on the bonding materials used in glass metallization connections. However, existing bonding materials still have the following problems: First, high-Bi systems suffer from mechanical reliability defects. Although high-Bi systems can lower reflow temperatures, solder joints are hard and brittle. After temperature cycling, cracks easily propagate along Bi-rich phases, solder / plating interfaces, or intermetallic compound boundaries, leading to conductive layer detachment and increased resistance in glass-plated connectors. Second, ordinary silver paste has insufficient conductivity. Ordinary silver paste relies on filler contact for conductivity, but resin water absorption and expansion, thermal aging and shrinkage, and electrochemical corrosion can change the contact pressure between fillers, causing the resistance change rate to exceed 10% after humid heat, salt spray, and electrically heated storage. Third, low-temperature tin powder suffers from sintering process defects. Low-temperature tin powder has an oxide layer on its surface. Without reactive activators and a curing design with a consistent temperature window, it is difficult for tin powder to form necks; after resin curing, it actually hinders intermetallic contact, resulting in unstable initial resistance and pull-out strength. Fourth, it is difficult to achieve unified treatment of multilayer heterogeneous interfaces. The surface chemical properties of glass, silver paste, ITO, FTO, nickel layer, copper terminals, and tin layer differ significantly. A single silane or flux cannot simultaneously meet the multiple requirements of glass hydroxyl condensation, metal oxide layer coordination, silver / copper / nickel surface passivation, and resin crosslinking. Fifth, flux residue poses a long-term reliability risk. Carboxylates, halogens, or metal ions remaining in ordinary flux may generate conductive dendrites, interface corrosion, or leakage channels under conditions of 80℃ / 96%RH and 12V power supply, ultimately leading to abnormal connection resistance and appearance failure. Sixth, there is a contradiction between curing process and temperature resistance. Curing at 160℃ / 15min requires rapid resin crosslinking, but hanging at 105℃ and hot storage at 105℃ / 500h require the cured network to have high Tg, low creep, and good toughness; ordinary fast-curing epoxy is prone to being too brittle or having insufficient resistance to humid heat, making it difficult to meet these requirements simultaneously. Seventh, the edges of the adhesive layer lack effective protection. Water, alcohol, surfactants, and alkaline salts in glass cleaners may seep into the edges of the adhesive layer. Combined with the transient thermal stress and mechanical impact caused by water impact, ordinary adhesive layer edges, if lacking hydrophobic sealing and tough buffering, are prone to whitening, cracking, discoloration, or peeling.

[0005] Therefore, how to provide a method to obtain conductivity close to that of low-temperature solder under conditions where the Bi element content is less than 10%, while obtaining interface toughness higher than that of ordinary solder paste and long-term resistance stability higher than that of ordinary conductive adhesive, and to maintain performance under specified temperature cycling, high temperature storage, high temperature and high humidity, high temperature hanging, cleaning agent immersion, neutral salt spray, long-term electrically heated storage and thermal shock conditions, is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention proposes a low-bismuth tin adhesive composite conductive bonding material, its preparation method, and its application.

[0007] To achieve the above objectives, the present invention provides the following technical solution: A low-bismuth tin adhesive composite conductive bonding material, comprising the following raw materials in parts by weight: The composition includes 55-82 parts of low bismuth-tin-based microalloy particles, 3-25 parts of conductive reinforcing filler, 8-28 parts of thermosetting soldering resin, 0.3-6 parts of latent curing agent, 0.2-5 parts of reactive activator, 0.1-4 parts of glass / metal amphiphilic coupling agent, 0.1-5 parts of ion scavenger, 0.05-3 parts of corrosion inhibitor, 0.5-8 parts of toughening agent, and 0.05-3 parts of defoamer.

[0008] Beneficial effects: The preferred mass ratio of the conductive reinforcing filler to the low-bismuth tin-based microalloy particles is 0.08-0.28. This ratio ensures that both the metal microbridge network and the redundant conductive network reach the continuity threshold, preventing overall circuit breakage due to single-path failure caused by resin water absorption and thermal stress after humid heat. The preferred mass ratio of the reactive activator to the ion scavenger is 0.5-3.0. Excessive activator increases the risk of ion migration under humid heat; excessive ion scavenger increases viscosity and affects the activator's contact with the metal oxide film. The optimal ratio balances flux activity and reliability stability. When the coupling agent content is below 0.1 parts, interfacial reinforcement is insufficient; when the content exceeds 4 parts by mass, it may cause abnormal resin crosslinking density, increased moisture absorption, or increased brittleness of the cured product.

[0009] Preferably, the low-bismuth tin-based microalloyed particles include Sn, and also include one or more of In, Ag, Cu, Ni, Sb, Ge, Zn or Bi; The mass fraction of Bi in the low bismuth-tin-based microalloyed particles is <10%.

[0010] Preferably, the low-bismuth tin-based microalloyed particles include Sn58-68 / In24-36 / Ag0.3-2.5 / Cu0.2-1.0 / Bi4.5-8.5 / Ni0.02-0.4 (Type A), Sn54-63 / In30-42 / Ag0.3-1.5 / Cu0.1-0.8 / Bi3.0-8.0 / Sb0.1-1.0 (Type B), Sn62-75 / In12-28 / Ag0.5-3.0 / Cu0.3-1.2 / Bi0.5-6.0 / Ni0.05-0.5 (Type C), Sn58-70 / In20-34 / Ag0.2-2.0 / Cu0.2-0.8 / Bi5.0-7.8 / Ge0.01-0.15 (Type D), Sn60-72 / One of the following: In18-32 / Cu0.4-1.5 / Bi4.0-8.0 / Sb0.2-1.2 / Ni0.05-0.3 (Type E).

[0011] Beneficial effects: Type A is a comprehensive type, suitable for glass silver paste layers and tin-plated copper tongues; Type B is a low-temperature rapid type, suitable for short-time curing below 160℃; Type C is a high-temperature creep resistant type, suitable for hanging loads at 105℃ and storing under electric heating; Type D is an oxidation resistant storage type, suitable for syringe dispensing and long shelf life; Type E is a low-silver cost type, suitable for large-area terminal connections.

[0012] Preferably, the conductive reinforcing filler includes one or more of the following: flake silver powder, spherical silver powder, silver-coated copper powder, tin-coated copper powder, silver-coated nickel powder, nickel powder, copper powder, graphene-silver composite powder, and silver nanowires. Preferably, it is a combination of flake silver powder and silver-coated copper powder, where the flake silver powder provides a low-resistance surface contact path, and the silver-coated copper powder reduces cost and forms a three-dimensional conductive framework.

[0013] The D50 of the conductive reinforcing filler is preferably 1-20 μm. Specifically, the flake diameter of the flake silver powder is preferably 2-12 μm, and the thickness is preferably 0.05-0.5 μm; the D50 of the silver-coated copper powder is preferably 5-18 μm, and the thickness of the silver coating layer is preferably 50-500 nm; the D50 of the tin-coated copper powder is preferably 3-15 μm, and the tin coating layer can form a metallurgical bond with the low-bismuth tin-based microalloy particles.

[0014] Beneficial effects: When the total amount of conductive reinforcing filler is too low, the contact between low bismuth-tin-based microalloy particles depends on the degree of local melting, and the initial resistance increases after short-term curing at low temperature; when the total amount of conductive reinforcing filler is too high, the resin phase is insufficient, the brittleness of the adhesive layer increases, and the printing or dispensing viscosity is too high.

[0015] Preferably, the thermosetting flux resin includes one or more of bisphenol F epoxy resin, bisphenol A epoxy resin, alicyclic epoxy resin, phenolic resin, polyurethane modified epoxy resin, siloxane modified epoxy resin, maleimide resin, benzoxazine resin, and epoxy-phenolic resin systems; preferably, bisphenol F epoxy and phenolic resin are compounded to balance low viscosity, rapid curing, interfacial adhesion, and resistance to damp heat.

[0016] Beneficial Effects: The glass transition temperature (Tg) of the thermosetting flux resin system in this invention after curing is preferably 115-165℃, the water absorption rate is preferably less than 1.2%, and the mass moisture absorption rate under 85℃ / 85%RH conditions is preferably less than 0.8%. When the Tg is below 105℃, high-temperature hanging and long-term electrically heated storage can easily cause creep of the adhesive layer; when the Tg is too high and there is a lack of toughening, the risk of edge cracking under water impact and temperature cycling increases. The thermosetting flux resin simultaneously serves as a flux carrier and a coating function after curing. Before curing, the resin should be able to wet the glass coating and metal terminals, releasing reactive activators to the surface of the metal powder; after curing, the resin should fix the activator residues, seal the pores between metal powders, and reduce the entry of moisture and ions.

[0017] The latent curing agent includes one or more of dicyandiamide, modified imidazole, microencapsulated imidazole, aromatic amine salts, acid anhydride microcapsules, blocked isocyanates, and boronamine complexes.

[0018] Beneficial effects: The latent curing agent maintains low reactivity when stored at 5°C, and is rapidly activated at 145-160°C, enabling the adhesive layer to reach transportable strength and a stable conductive structure within 15 minutes.

[0019] Preferably, the reactive activator includes one or more of the following: carboxyl-terminated polyester, carboxyl-modified epoxy, hydroxycarboxylic acid, phosphate ester, imidazole carboxylate, mercaptocarboxylic acid derivative, acid anhydride compound, or organic acid containing epoxy reactive group.

[0020] More preferably, the reactive activator has an acid value of 20-180 mg KOH / g and a decomposition or activation temperature of 80-150℃.

[0021] Beneficial effects: The reactive activator in this invention is used to remove the oxide film on the surface of tin, copper, silver, nickel or tin plating before curing, and promotes local liquid phase wetting of low bismuth tin-based microalloy particles; during the curing process, it participates in resin crosslinking or interfacial coordination through carboxyl, hydroxyl, epoxy, imidazole, phosphate ester or mercapto groups, and does not remain in large quantities as free small molecules after curing.

[0022] This invention preferably does not use halogen activators, or the halogen content is controlled below 900 ppm, more preferably below 300 ppm. The conductivity of the water extract of the solidified product is preferably below 50 μS / cm, and the Na... + K + Cl - The content of a single ion is preferably less than 30 ppm.

[0023] Preferably, the glass / metal amphiphilic coupling agent includes silane coupling agents and metal affinity coupling agents; The silane coupling agent includes one of epoxy silane, amino silane, mercapto silane, methacryloxy silane, and alkoxy silane oligomers; The metal affinity coupling agent may be selected from one of the following: phosphate ester, titanate ester, zirconate ester, mercaptotriazine, and reactive compounds containing a benzotriazole structure.

[0024] Beneficial effects: The aforementioned silane coupling agent condenses with the silanol groups on the glass surface to form a Si-O-Si interface bridge; the metal affinity coupling agent forms a coordination, chemisorption, or reaction layer with the surfaces of silver, copper, nickel, tin, indium tin oxide, or tin oxide; the organic end of the coupling agent co-crosslinks with epoxy, phenolic, or polyurethane modified resins. The amphiphilic coupling system formed by these two components forms a stress-buffered interface layer at the glass edge, the metal tongue edge, and the boundary of the conductive plating layer, reducing shear stress concentration during temperature cycling. This interface layer also improves the pull-out retention rate after humid heating and inhibits whitening, blistering, and edge debonding after immersion in cleaning agents.

[0025] Preferably, the ion scavenging agent includes one or more of the following: hydrotalcite, modified hydrotalcite, zeolite, zirconium phosphate, layered double hydroxide, ion exchange resin powder, and alumina silicate. The ion scavenger has a particle size D50 of 0.2-3 μm, and its surface can be modified with silane or epoxy functional groups to improve the dispersion stability of the resin phase.

[0026] The corrosion inhibitor is one or more of the following: benzotriazole, methylbenzotriazole, mercaptobenzothiazole, mercaptotriazine, imidazole derivatives, organophosphates, and molybdate microcapsules; Beneficial effects: The above-mentioned corrosion inhibitor is used to passivate the surfaces of copper, silver, nickel, and tin, inhibiting the dissolution of metal ions under salt spray and electrothermal conditions. The hydrophobic system forms a low surface energy region at the edge of the adhesive layer, reducing the rate of penetration of cleaning agents, salt spray water films, and humid water vapor along the interface. The ion trap, corrosion inhibitor, and hydrophobic system together constitute a reliable closed structure. This structure controls the resistivity change rate to within 10% after 500 hours of humid heat, eliminates continuous corrosion channels after 96 hours of neutral salt spray, and prevents the formation of visible dendrites and leakage paths after 500 hours of electrothermal storage at 105℃ / 12V.

[0027] The defoamer includes one or more of the following: polyether-modified polysiloxane, fluorinated polysiloxane, silicone-polyether copolymer, and non-silicone defoamers (such as polyacrylates and polyvinyl isobutyl ethers); preferably, it is polyether-modified polydimethylsiloxane (such as BYK-1790, BYK-1788, or Dow Corning DC-163), with an addition amount of 0.05-3 parts, used to suppress microbubble residue during vacuum defoaming and dispensing, and to prevent the formation of pores in the adhesive layer after curing, which would reduce the conductive cross-sectional area.

[0028] A method for preparing a low-bismuth tin adhesive composite conductive bonding material includes the following steps: After adding the toughening agent to the mother liquor of the thermosetting flux resin, a latent curing agent, a reactive activator, a glass / metal amphiphilic coupling agent, an ion scavenger, a corrosion inhibitor, and a defoamer are added and dispersed evenly. Then, conductive reinforcing fillers are added in batches to the resulting mixture and stirred and dispersed. Finally, low bismuth tin-based microalloy particles are added, stirred, ground, and dispersed to obtain the low bismuth tin adhesive composite conductive bonding material.

[0029] Application of a low-bismuth tin adhesive composite conductive bonding material in glass metallization bonding.

[0030] More preferably, the glass metallization connection includes glass metallization connections in automotive rear window heating wire terminals, glass antenna terminals, dimming glass terminals, electrochromic glass terminals, photovoltaic glass busbars, or glass-based sensor terminals.

[0031] A glass metallization bonding method includes the following steps: The metal terminal and the glass coating surface are bonded together using the aforementioned low-bismuth tin adhesive composite conductive bonding material to obtain a bonded part. The bonded part is then cured at 160-170℃ for 10-13 minutes to complete the glass metallization connection.

[0032] More preferably, the thickness of the low bismuth-tin adhesive composite conductive bonding material in the bonding component is 30-180 μm.

[0033] More preferably, the metal terminal is a tin-plated copper tongue, a nickel-plated copper terminal, a stainless steel terminal, a flexible copper foil, or a flexible circuit board gold finger.

[0034] The glass coating includes a conductive coating on the glass surface, which may be a silver paste sintered layer, an ITO layer, an FTO layer, a nickel-copper composite coating, or a sensing electrode layer.

[0035] Compared with the prior art, the present invention has the following advantages and technical effects: This invention uses low-bismuth tin-based microalloyed particles to replace traditional high-Bi low-temperature solder as the main metal bonding phase, achieving low-temperature metal microbridge formation even with a Bi content below 10% by mass. Simultaneously, this invention constructs a redundant conductive network through conductive reinforcing fillers, ensuring stable conductivity of the adhesive layer during the initial curing stage, after temperature cycling, after humid heat, and after electrothermal treatment. Furthermore, this invention employs a same-temperature window design for the thermosetting flux resin and reactive activator, enabling the fluxing, wetting, microbridge formation, and resin crosslinking processes to be completed synergistically within 160℃ / 15min. Building upon this, this invention enhances the interfacial bonding between the glass coating, the transparent conductive oxide layer, the metal terminals, and the resin through a glass / metal amphiphilic coupling system. Further, this invention utilizes the synergistic effect of ion trapping agents, corrosion inhibitors, and hydrophobic additives to improve the reliability of the product under humid heat, salt spray, cleaning agent immersion, and electrothermal storage conditions. Ultimately, the low-bismuth tin adhesive cured body formed by this invention can achieve an initial pull-out force greater than 50N (preferably greater than 80N) in glass metallization bonding, and maintain a resistance change rate of less than 10% after specified environmental testing. This invention is suitable for combination with automatic dispensing, thermosetting curing, and online four-wire resistance detection. Mass production lines can be equipped with adhesive application amount detection, terminal pressure detection, curing temperature profile recording, and initial resistance screening to reduce reliability variability. Furthermore, the raw materials provided by this invention are readily available, the preparation method is simple, and it is easy to promote and apply. Detailed Implementation

[0036] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to specific embodiments.

[0038] Unless otherwise specified, all raw materials used in the embodiments of this invention were purchased through commercial channels; Unless otherwise specified, room temperature or normal temperature in the embodiments of the present invention refers to 25±3℃.

[0039] Example 1 A low-bismuth tin adhesive composite conductive bonding material, based on the Sn-In-Ag-Cu-Bi-Ni low-bismuth tin adhesive type, comprises the following raw materials in parts by weight: 68.0 parts of Sn-In-Ag-Cu-Bi-Ni microalloyed powder (Sn63 / In28 / Ag1.5 / Cu0.4 / Bi7.0 / Ni0.1, bimodal D50=6μm / 24μm), 6.0 parts of flake silver powder (D50=3μm), 5.0 parts of silver-coated copper powder (D50=12μm), 8.5 parts of bisphenol F epoxy resin, 2.0 parts of phenol-oxygen resin, 1.6 parts of carboxyl-terminated polyester activator, 1.8 parts of microcapsule imidazole curing agent, 1.1 parts of glass / metal amphiphilic coupling agent (0.5 parts of epoxy silane, 0.6 parts of phosphate metal affinity coupling agent), 1.2 parts of modified hydrotalcite / zirconium phosphate ion scavenger, 0.4 parts of benzotriazole corrosion inhibitor, 2.4 parts of core-shell rubber toughening agent, and 2.0 parts of polyether-modified polydimethylsiloxane defoamer.

[0040] A method for preparing a low-bismuth tin adhesive composite conductive bonding material includes the following steps: (1) Preparation of low bismuth tin-based microalloyed particles Metal powders were weighed according to the following ratios: Sn63 / In28 / Ag1.5 / Cu0.4 / Bi7.0 / Ni0.1. The powders were then mixed and melted at 520℃ for 3 hours under an inert atmosphere, followed by gas atomization to obtain spherical or near-spherical powders. The powders were sieved to obtain two particle size fractions: fine powder (D50) of 6 μm and coarse powder (D50) of 24 μm. After sieving, the powders underwent mild surface reduction in a nitrogen, hydrogen-nitrogen mixture, or vacuum environment, followed by thin-layer protection with organic acid salts.

[0041] (2) Add bisphenol F epoxy and phenolic resin to the reactor and stir at 40-80℃ until uniformly dispersed. Add core-shell rubber toughening agent and control the viscosity at 25℃ to 2-20 Pa·s to obtain resin mother liquor. When the temperature of the resin mother liquor is 30-45℃, add microcapsule imidazole curing agent, carboxyl-terminated polyester activator, epoxy silane, phosphate coupling agent, benzotriazole corrosion inhibitor, modified hydrotalcite / zirconium phosphate ion scavenger and polyether-modified polydimethylsiloxane defoamer. Vacuum dispersion or planetary dispersion is used to make the powder agglomeration particle size less than 20μm to avoid local agglomeration of ion scavenger causing dispensing needle blockage.

[0042] (3) Add flake silver powder and silver-coated copper powder to the mixture obtained in step (2) in three batches. First, stir at a low speed of 500 r / min to achieve surface wetting, and then disperse at a medium speed of 1500 r / min to form a uniform conductive filler suspension. Add the low bismuth tin-based microalloy particles obtained in step (1) to the mixture in an environment with a relative humidity of less than 40%. Dispersion is carried out by double planetary vacuum stirring, three-roll milling or planetary centrifugal mixing to control the uniformity, viscosity and thixotropy of the metal powder. The preferred gaps of the three-roll milling are 80 μm, 50 μm and 30 μm respectively to avoid excessive shearing that causes deformation and oxidation of the metal powder. After uniform dispersion, degas for 20 min under conditions of -0.08 to -0.10 MPa. When used for syringe dispensing, it can be filtered through a 150 μm stainless steel filter or nylon filter. When used for stencil printing, it is not filtered but the maximum agglomerate is controlled to be less than one-third of the stencil opening size. Finally, a low bismuth tin adhesive composite conductive adhesive material is obtained.

[0043] (4) The obtained low bismuth tin adhesive composite conductive adhesive material is packed into a light-proof syringe, aluminum can or pre-formed film packaging and stored at 5±3℃. The viscosity change rate is less than 20% after 30 days at 5℃. After restoring to room temperature for 2 hours, there is no obvious layering, skinning or hardening.

[0044] Example 2 A low-bismuth tin adhesive composite conductive bonding material, specifically a Sn-In-Ag-Cu-Bi-Ni low-bismuth tin adhesive with high conductivity, comprises the following raw materials in parts by weight: 60.0 parts of Sn-In-Ag-Cu-Bi-Ni microalloyed powder (Sn63 / In28 / Ag1.5 / Cu0.4 / Bi7.0 / Ni0.1, bimodal D50=6μm / 24μm), 10.0 parts of flake silver powder (D50=3μm), 8.0 parts of silver-coated copper powder (D50=12μm), 8.0 parts of bisphenol F epoxy resin, 2.0 parts of phenol-oxygen resin, 1.6 parts of carboxyl-terminated polyester activator, 1.8 parts of microcapsule imidazole curing agent, 1.1 parts of glass / metal amphiphilic coupling agent (0.5 parts of epoxy silane, 0.6 parts of phosphate metal affinity coupling agent), 1.2 parts of modified hydrotalcite / zirconium phosphate ion scavenger, 0.4 parts of benzotriazole corrosion inhibitor, 2.0 parts of core-shell rubber toughening agent, and 2.0 parts of polyether-modified polydimethylsiloxane defoamer.

[0045] A method for preparing a low-bismuth tin adhesive composite conductive bonding material includes the following steps: (1) Preparation of low bismuth tin-based microalloyed particles Metal powders were weighed according to the following ratios: Sn63 / In28 / Ag1.5 / Cu0.4 / Bi7.0 / Ni0.1. The powders were then mixed and melted at 520℃ for 3 hours under an inert atmosphere, followed by gas atomization to obtain spherical or near-spherical powders. The powders were sieved to obtain two particle size fractions: fine powder (D50) of 6 μm and coarse powder (D50) of 24 μm. After sieving, the powders underwent mild surface reduction in a nitrogen, hydrogen-nitrogen mixture, or vacuum environment, followed by thin-layer protection with organic acid salts.

[0046] (2) Add bisphenol F epoxy and phenolic resin to the reactor and stir at 40-80℃ until uniformly dispersed. Add core-shell rubber toughening agent and control the viscosity at 25℃ to 2-20 Pa·s to obtain resin mother liquor. When the temperature of the resin mother liquor is 30-45℃, add microcapsule imidazole curing agent, carboxyl-terminated polyester activator, epoxy silane / phosphate coupling agent, benzotriazole corrosion inhibitor, modified hydrotalcite / zirconium phosphate ion scavenger and polyether-modified polydimethylsiloxane defoamer. Vacuum dispersion or planetary dispersion is used to make the powder agglomeration particle size less than 20μm to avoid local agglomeration of ion scavenger causing dispensing needle blockage.

[0047] (3) Add flake silver powder and silver-coated copper powder to the mixture obtained in step (2) in three batches. First, stir at a low speed of 500 r / min to achieve surface wetting, and then disperse at a medium speed of 1500 r / min to form a uniform conductive filler suspension. Add the low bismuth tin-based microalloy particles obtained in step (1) to the mixture in an environment with a relative humidity of less than 40%. Dispersion is carried out by double planetary vacuum stirring, three-roll milling or planetary centrifugal mixing to control the uniformity, viscosity and thixotropy of the metal powder. The preferred gaps of the three-roll milling are 80 μm, 50 μm and 30 μm respectively to avoid excessive shearing that causes deformation and oxidation of the metal powder. After uniform dispersion, degas for 20 min under conditions of -0.08 to -0.10 MPa. When used for syringe dispensing, it can be filtered through a 150 μm stainless steel filter or nylon filter. When used for stencil printing, it is not filtered but the maximum agglomerate is controlled to be less than one-third of the stencil opening size. Finally, a low bismuth tin adhesive composite conductive adhesive material is obtained.

[0048] (4) The obtained low bismuth tin adhesive composite conductive adhesive material is packed into a light-proof syringe, aluminum can or pre-formed film packaging and stored at 5±3℃. The viscosity change rate is less than 20% after 30 days at 5℃. After restoring to room temperature for 2 hours, there is no obvious layering, skinning or hardening.

[0049] Example 3 A low-bismuth tin adhesive composite conductive bonding material, specifically a Sn-In-Ag-Cu-Bi-Ni low-bismuth tin adhesive with high toughness, comprises the following raw materials in parts by weight: 66.0 parts of Sn-In-Ag-Cu-Bi-Ni microalloyed powder (Sn63 / In28 / Ag1.5 / Cu0.4 / Bi7.0 / Ni0.1, bimodal D50=6μm / 24μm), 6.0 parts of flake silver powder (D50=3μm), 5.0 parts of silver-coated copper powder (D50=12μm), 8.5 parts of bisphenol F epoxy resin, 2.0 parts of phenol-oxygen resin, 1.6 parts of carboxyl-terminated polyester activator, 1.8 parts of microencapsulated imidazole curing agent, 0.5 parts of epoxy silane, 0.6 parts of phosphate metal affinity coupling agent, 1.2 parts of modified hydrotalcite / zirconium phosphate ion scavenger, 0.4 parts of benzotriazole corrosion inhibitor, 4.4 parts of core-shell rubber toughening agent, and 2.0 parts of polyether-modified polydimethylsiloxane defoamer.

[0050] A method for preparing a low-bismuth tin adhesive composite conductive bonding material includes the following steps: (1) Preparation of low bismuth tin-based microalloyed particles Metal powders were weighed according to the following ratios: Sn63 / In28 / Ag1.5 / Cu0.4 / Bi7.0 / Ni0.1. The powders were then mixed and melted at 520℃ for 3 hours under an inert atmosphere, followed by gas atomization to obtain spherical or near-spherical powders. The powders were sieved to obtain two particle size fractions: fine powder (D50) of 6 μm and coarse powder (D50) of 24 μm. After sieving, the powders underwent mild surface reduction in a nitrogen, hydrogen-nitrogen mixture, or vacuum environment, followed by thin-layer protection with organic acid salts.

[0051] (2) Add bisphenol F epoxy and phenolic resin to the reactor and stir at 40-80℃ until uniformly dispersed. Add core-shell rubber toughening agent and control the viscosity at 25℃ to 2-20 Pa·s to obtain resin mother liquor. When the temperature of the resin mother liquor is 30-45℃, add microcapsule imidazole curing agent, carboxyl-terminated polyester activator, epoxy silane / phosphate coupling agent, benzotriazole corrosion inhibitor, modified hydrotalcite / zirconium phosphate ion scavenger and polyether-modified polydimethylsiloxane defoamer. Vacuum dispersion or planetary dispersion is used to make the powder agglomeration particle size less than 20μm to avoid local agglomeration of ion scavenger causing dispensing needle blockage.

[0052] (3) Add flake silver powder and silver-coated copper powder to the mixture obtained in step (2) in three batches. First, stir at a low speed of 500 r / min to achieve surface wetting, and then disperse at a medium speed of 1500 r / min to form a uniform conductive filler suspension. Add the low bismuth tin-based microalloy particles obtained in step (1) to the mixture in an environment with a relative humidity of less than 40%. Dispersion is carried out by double planetary vacuum stirring, three-roll milling or planetary centrifugal mixing to control the uniformity, viscosity and thixotropy of the metal powder. The preferred gaps of the three-roll milling are 80 μm, 50 μm and 30 μm respectively to avoid excessive shearing that causes deformation and oxidation of the metal powder. After uniform dispersion, degas for 20 min under conditions of -0.08 to -0.10 MPa. When used for syringe dispensing, it can be filtered through a 150 μm stainless steel filter or nylon filter. When used for stencil printing, it is not filtered but the maximum agglomerate is controlled to be less than one-third of the stencil opening size. Finally, a low bismuth tin adhesive composite conductive adhesive material is obtained.

[0053] (4) The obtained low bismuth tin adhesive composite conductive adhesive material is packed into a light-proof syringe, aluminum can or pre-formed film packaging and stored at 5±3℃. The viscosity change rate is less than 20% after 30 days at 5℃. After restoring to room temperature for 2 hours, there is no obvious layering, skinning or hardening.

[0054] Example 4 A low-bismuth tin adhesive composite conductive bonding material, specifically a Sn-In-Ag-Cu-Bi-Ni low-bismuth tin adhesive with moisture and heat resistance and low ion content, comprises the following raw materials in parts by weight: 65.0 parts of Sn-In-Ag-Cu-Bi-Ni microalloyed powder (Sn63 / In28 / Ag1.5 / Cu0.4 / Bi7.0 / Ni0.1, bimodal D50=6μm / 24μm), 6.0 parts of flake silver powder (D50=3μm), 5.0 parts of silver-coated copper powder (D50=12μm), 8.0 parts of bisphenol F epoxy resin, 2.0 parts of phenol-oxygen resin, 1.6 parts of carboxyl-terminated polyester activator, 1.8 parts of microencapsulated imidazole curing agent, 0.5 parts of epoxy silane, 0.6 parts of phosphate metal affinity coupling agent, 2.2 parts of modified hydrotalcite / zirconium phosphate ion scavenger, 0.8 parts of benzotriazole corrosion inhibitor, 2.4 parts of core-shell rubber toughening agent, and 2.0 parts of polyether-modified polydimethylsiloxane defoamer.

[0055] A method for preparing a low-bismuth tin adhesive composite conductive bonding material includes the following steps: (1) Preparation of low bismuth tin-based microalloyed particles Metal powders were weighed according to the following ratios: Sn63 / In28 / Ag1.5 / Cu0.4 / Bi7.0 / Ni0.1. The powders were then mixed and melted at 520℃ for 3 hours under an inert atmosphere, followed by gas atomization to obtain spherical or near-spherical powders. The powders were sieved to obtain two particle size fractions: fine powder (D50) of 6 μm and coarse powder (D50) of 24 μm. After sieving, the powders underwent mild surface reduction in a nitrogen, hydrogen-nitrogen mixture, or vacuum environment, followed by thin-layer protection with organic acid salts.

[0056] (2) Add bisphenol F epoxy and phenolic resin to the reactor and stir at 40-80℃ until uniformly dispersed. Add core-shell rubber toughening agent and control the viscosity at 25℃ to 2-20 Pa·s to obtain resin mother liquor. When the temperature of the resin mother liquor is 30-45℃, add microcapsule imidazole curing agent, carboxyl-terminated polyester activator, epoxy silane / phosphate coupling agent, benzotriazole corrosion inhibitor, modified hydrotalcite / zirconium phosphate ion scavenger and polyether-modified polydimethylsiloxane defoamer. Vacuum dispersion or planetary dispersion is used to make the powder agglomeration particle size less than 20μm to avoid local agglomeration of ion scavenger causing dispensing needle blockage.

[0057] (3) Add flake silver powder and silver-coated copper powder to the mixture obtained in step (2) in three batches. First, stir at a low speed of 500 r / min to achieve surface wetting, and then disperse at a medium speed of 1500 r / min to form a uniform conductive filler suspension. Add the low bismuth tin-based microalloy particles obtained in step (1) to the mixture in an environment with a relative humidity of less than 40%. Dispersion is carried out by double planetary vacuum stirring, three-roll milling or planetary centrifugal mixing to control the uniformity, viscosity and thixotropy of the metal powder. The preferred gaps of the three-roll milling are 80 μm, 50 μm and 30 μm respectively to avoid excessive shearing that causes deformation and oxidation of the metal powder. After uniform dispersion, degas for 20 min under conditions of -0.08 to -0.10 MPa. When used for syringe dispensing, it can be filtered through a 150 μm stainless steel filter or nylon filter. When used for stencil printing, it is not filtered but the maximum agglomerate is controlled to be less than one-third of the stencil opening size. Finally, a low bismuth tin adhesive composite conductive adhesive material is obtained.

[0058] (4) The obtained low bismuth tin adhesive composite conductive adhesive material is packed into a light-proof syringe, aluminum can or pre-formed film packaging and stored at 5±3℃. The viscosity change rate is less than 20% after 30 days at 5℃. After restoring to room temperature for 2 hours, there is no obvious layering, skinning or hardening.

[0059] Example 5 A low-bismuth tin adhesive composite conductive bonding material, specifically a low-cost Sn-In-Ag-Cu-Bi-Ni low-bismuth tin adhesive, comprises the following raw materials in parts by weight: 72.0 parts of Sn-In-Ag-Cu-Bi-Ni microalloyed powder (Sn63 / In28 / Ag1.5 / Cu0.4 / Bi7.0 / Ni0.1, bimodal D50=6μm / 24μm), 4.0 parts of flake silver powder (D50=3μm), 4.0 parts of silver-coated copper powder (D50=12μm), 7.5 parts of bisphenol F epoxy resin, 2.0 parts of phenol-oxygen resin, 1.6 parts of carboxyl-terminated polyester activator, 1.8 parts of microencapsulated imidazole curing agent, 0.5 parts of epoxy silane, 0.6 parts of phosphate metal affinity coupling agent, 1.2 parts of modified hydrotalcite / zirconium phosphate ion scavenger, 0.4 parts of benzotriazole corrosion inhibitor, 2.4 parts of core-shell rubber toughening agent, and 2.0 parts of polyether-modified polydimethylsiloxane defoamer.

[0060] A method for preparing a low-bismuth tin adhesive composite conductive bonding material includes the following steps: (1) Preparation of low bismuth tin-based microalloyed particles Metal powders were weighed according to the following ratios: Sn63 / In28 / Ag1.5 / Cu0.4 / Bi7.0 / Ni0.1. The powders were then mixed and melted at 520℃ for 3 hours under an inert atmosphere, followed by gas atomization to obtain spherical or near-spherical powders. The powders were sieved to obtain two particle size fractions: fine powder (D50) of 6 μm and coarse powder (D50) of 24 μm. After sieving, the powders underwent mild surface reduction in a nitrogen, hydrogen-nitrogen mixture, or vacuum environment, followed by thin-layer protection with organic acid salts.

[0061] (2) Add bisphenol F epoxy and phenolic resin to the reactor and stir at 40-80℃ until uniformly dispersed. Add core-shell rubber toughening agent and control the viscosity at 25℃ to 2-20 Pa·s to obtain resin mother liquor. When the temperature of the resin mother liquor is 30-45℃, add microcapsule imidazole curing agent, carboxyl-terminated polyester activator, epoxy silane / phosphate coupling agent, benzotriazole corrosion inhibitor, modified hydrotalcite / zirconium phosphate ion scavenger and polyether-modified polydimethylsiloxane defoamer. Vacuum dispersion or planetary dispersion is used to make the powder agglomeration particle size less than 20μm to avoid local agglomeration of ion scavenger causing dispensing needle blockage.

[0062] (3) Add flake silver powder and silver-coated copper powder to the mixture obtained in step (2) in three batches. First, stir at a low speed of 500 r / min to achieve surface wetting, and then disperse at a medium speed of 1500 r / min to form a uniform conductive filler suspension. Add the low bismuth tin-based microalloy particles obtained in step (1) to the mixture in an environment with a relative humidity of less than 40%. Dispersion is carried out by double planetary vacuum stirring, three-roll milling or planetary centrifugal mixing to control the uniformity, viscosity and thixotropy of the metal powder. The preferred gaps of the three-roll milling are 80 μm, 50 μm and 30 μm respectively to avoid excessive shearing that causes deformation and oxidation of the metal powder. After uniform dispersion, degas for 20 min under conditions of -0.08 to -0.10 MPa. When used for syringe dispensing, it can be filtered through a 150 μm stainless steel filter or nylon filter. When used for stencil printing, it is not filtered but the maximum agglomerate is controlled to be less than one-third of the stencil opening size. Finally, a low bismuth tin adhesive composite conductive adhesive material is obtained.

[0063] (4) The obtained low bismuth tin adhesive composite conductive adhesive material is packed into a light-proof syringe, aluminum can or pre-formed film packaging and stored at 5±3℃. The viscosity change rate is less than 20% after 30 days at 5℃. After restoring to room temperature for 2 hours, there is no obvious layering, skinning or hardening.

[0064] Application Example 1 The application of a low-bismuth tin adhesive composite conductive bonding material in glass metallization bonding includes the following steps: (1) The surfaces of the glass coating (silver paste sintered layer) and the metal tongue (tin-plated copper tongue) are subjected to dust removal, degreasing, and drying treatment. The tin adhesive obtained in Example 1 is applied to the connection area between the glass coating and the metal tongue by dispensing, printing, or scraping, with a wet film thickness preferably of 80-110 μm. After the metal tongue is bonded, a pressure of 0.25 MPa is applied to spread the adhesive layer and expel interfacial air.

[0065] (2) Place the bonding parts at 145℃ for 2 minutes, and then keep them at 160℃ for 12 minutes. Curing can be done by hot air furnace, infrared, hot press plate, pulse hot press or induction auxiliary heating. After curing, let them cool naturally to below 40℃ before removing the clamps to avoid damage to the glass coating caused by hot peel stress.

[0066] Application Example 2 The application of a low-bismuth tin adhesive composite conductive bonding material in glass metallization bonding includes the following steps: (1) The surfaces of the glass coating (silver paste sintered layer) and the metal tongue (copper tongue) are subjected to dust removal, degreasing, and drying treatment. The tin adhesive obtained in Example 2 is applied to the connection area between the glass coating and the metal tongue by dispensing, printing, or scraping, with a wet film thickness preferably of 70-100 μm. After the metal tongues are bonded, a pressure of 0.30 MPa is applied to spread the adhesive layer and expel interfacial air.

[0067] (2) Place the bonding parts at 145℃ for 2 minutes, and then keep them at 160℃ for 12 minutes. Curing can be done by hot air furnace, infrared, hot press plate, pulse hot press or induction auxiliary heating. After curing, let them cool naturally to below 40℃ before removing the clamps to avoid damage to the glass coating caused by hot peel stress.

[0068] Application Example 3 The application of a low-bismuth tin adhesive composite conductive bonding material in glass metallization bonding includes the following steps: (1) The surfaces of the glass coating (silver paste sintered layer) and the metal tongue (stainless steel terminal) are subjected to dust removal, degreasing, and drying treatment. The tin adhesive obtained in Example 3 is applied to the connection area between the glass coating and the metal tongue by dispensing, printing, or scraping, with a wet film thickness preferably of 65-95 μm. After the metal tongue is bonded, a pressure of 0.35 MPa is applied to spread the adhesive layer and expel interfacial air.

[0069] (2) Place the bonding parts at 145℃ for 2 minutes, and then keep them at 165℃ for 13 minutes. Curing can be done by hot air furnace, infrared, hot press plate, pulse hot press or induction auxiliary heating. After curing, let them cool naturally to below 40℃ before removing the clamps to avoid damage to the glass coating caused by hot peel stress.

[0070] Application Example 4 The application of a low-bismuth tin adhesive composite conductive bonding material in glass metallization bonding includes the following steps: (1) The surfaces of the glass coating (ITO layer) and the metal tongue (nickel-plated copper terminal) are subjected to dust removal, degreasing, and drying treatment. The tin adhesive obtained in Example 4 is applied to the connection area between the glass coating and the metal tongue by dispensing, printing, or scraping, with a wet film thickness preferably of 70-100 μm. After the metal tongue is bonded, a pressure of 0.22 MPa is applied to spread the adhesive layer and expel interfacial air.

[0071] (2) Place the bonding parts at 145℃ for 2 minutes, and then keep them at 165℃ for 13 minutes. Curing can be done by hot air furnace, infrared, hot press plate, pulse hot press or induction auxiliary heating. After curing, let them cool naturally to below 40℃ before removing the clamps to avoid damage to the glass coating caused by hot peel stress.

[0072] After curing, the product is stabilized by low-temperature baking at 60℃ for 30 minutes, and then naturally cooled to below 40℃ before the fixture is removed.

[0073] Application Example 5 The application of a low-bismuth tin adhesive composite conductive bonding material in glass metallization bonding includes the following steps: (1) The surfaces of the glass coating (silver paste sintered layer) and the metal tongue (tin-plated copper tongue) are subjected to dust removal, degreasing, and drying treatment. The tin adhesive obtained in Example 5 is applied to the connection area between the glass coating and the metal tongue by dispensing, printing, or scraping, with a wet film thickness preferably of 80-110 μm. After the metal tongue is bonded, a pressure of 0.25 MPa is applied to spread the adhesive layer and expel interfacial air.

[0074] (2) Place the bonding parts at 145℃ for 2 minutes, and then keep them at 160℃ for 12 minutes. Curing can be done by hot air furnace, infrared, hot press plate, pulse hot press or induction auxiliary heating. After curing, let them cool naturally to below 40℃ before removing the clamps to avoid damage to the glass coating caused by hot peel stress.

[0075] Comparative Example 1 A glass metallization bonding material is a high-Bi solder system comprising the following raw materials in parts by weight: 85 parts Sn42Bi58 solder powder and 15 parts conventional rosin flux.

[0076] The preparation method includes the following steps: Sn42Bi58 solder powder and conventional rosin flux are mixed and stirred evenly according to the above ratio to obtain high-Bi solder paste; it is applied to the glass coating and metal tongue connection area, and reflowed and cured at 160°C to obtain the connector.

[0077] Comparative Example 2 A glass metallization bonding material is a pure silver paste system, comprising the following raw materials in parts by weight: 75 parts silver powder and 25 parts epoxy resin (excluding low bismuth tin-based microalloying powder).

[0078] The preparation method includes the following steps: mixing silver powder with epoxy resin and conventional curing agent until uniform to obtain conductive silver paste; applying it to the glass coating and metal tongue connection area, and curing it at 160°C to obtain the connector.

[0079] Comparative Example 3 A glass metallization bonding material is a low-bismuth tin adhesive system without conductive reinforcing filler, comprising the following raw materials in parts by weight: 70 parts of low-bismuth tin powder (Sn63 / In28 / Ag1.5 / Cu0.4 / Bi7.0 / Ni0.1) and 30 parts of epoxy resin.

[0080] The preparation method includes the following steps: mixing low-bismuth tin powder with epoxy resin and conventional curing agent until uniform to obtain low-bismuth tin adhesive; applying it to the glass coating and metal tongue connection area, and curing at 160°C to obtain the connector.

[0081] Comparative Example 4 A glass metallization bonding material differs from Example 1 only in that it does not include the modified hydrotalcite / zirconium phosphate ion scavenger and benzotriazole corrosion inhibitor; the remaining components and amounts are the same as in Example 1.

[0082] The preparation method includes the following steps: the same steps as in Example 1 are followed, except that modified hydrotalcite / zirconium phosphate ion scavenger and benzotriazole corrosion inhibitor are not added, to obtain the low bismuth tin adhesive composite conductive adhesive material of Comparative Example 4.

[0083] Comparative Example 5 A glass metallization bonding material differs from Example 1 only in that it does not include epoxy silane and phosphate ester metal affinity coupling agent; the remaining components and amounts are the same as in Example 1.

[0084] The preparation method includes the following steps: the same steps as in Example 1 are followed, except that epoxy silane and phosphate ester metal affinity coupling agent are not added, to obtain the low bismuth tin adhesive composite conductive adhesive material of Comparative Example 5.

[0085] Compare and contrast examples 1-5 The only difference from Application Example 1 is that the bonding material obtained in Comparative Examples 1-5 is used. All other process steps and parameters are the same as in Application Example 1.

[0086] Technical effect 1. After the low bismuth-tin adhesive composite conductive bonding material provided by the present invention is cured, the bonding strength is characterized by a pull-out force test. The residual adhesive failure surface after the pull-out force test shows that there are no obvious bubbles or holes at the interface, and no visible debonding or microcracks.

[0087] 2. The initial contact resistance of the connectors obtained by the four-wire method test in Application Examples 1-5 and Comparative Application Examples 1-5 was measured between the terminals and the glass coating.

[0088] Refer to GB / T 7124 Adhesives Tensile Shear Strength Test Method (Vertical Pull-out) to perform an initial pull-out test at a vertical angle and record the failure mode; According to GB / T 2423.22 Temperature Change Test, the resistance change rate after 60 cycles from -40 to 105℃ is tested. According to GB / T 2423.2, the resistivity change rate after storage at 120℃ for 24 hours is tested. According to GB / T 2423.3 constant damp heat test, the resistivity change rate is tested under high temperature and high humidity conditions of 80℃ and 96%RH for 500h. Referring to the hanging weight test method in GB / T 4851-2014, the load-bearing capacity of hanging a 10N weight at 105℃ for 96h or 500h was tested, and the resistance change rate after the ring test was recorded. Specifically, the cured tongue was placed face down with a 1Kg weight hanging on it, and the oven was placed at 105℃. The weight was observed to fall off at different time periods. The test included the following steps: the connector was completely immersed in the glass stripper at 23°C for 24 hours, then removed, wiped clean, and the appearance of the adhesive layer was observed and the resistance change rate was tested.

[0089] A neutral salt spray test was conducted according to DIN EN ISO 9227 standard, with experimental conditions of pH=6.5-7.2 and temperature 35±2℃. The resistivity change rate and corrosion channels were measured after 96 hours.

[0090] According to IEC 60068-2-2 (high temperature energization), the resistance change rate was tested at 105℃ and 12V for 500 hours under long-term energized heat storage. The thermal shock test was conducted according to IEC 60068-2-14 (thermal shock). After maintaining the temperature at 105°C for 1 hour, the water was subjected to a shock of 3-4 L / 3s at a temperature of 23±5°C or lower. The appearance condition was recorded on the 5th and 10th shocks.

[0091] The results are shown in Table 1: Table 1. Performance test results of the connectors obtained from Application Examples 1-5 and Comparative Application Examples 1-5 As shown in Table 1, the initial resistance of the connectors obtained in Examples 1-5 was all below 5 mΩ, the initial pull-out force was all above 75 N, and the resistance change rate after each environmental test was all below 7%, with no abnormal appearance after thermal shock. In contrast, the resistance change rate of Comparative Example 1 (high Bi solder) reached 15.2% after temperature cycling and the edge cracked after thermal shock. The initial pull-out force of Comparative Example 2 (pure silver paste) was only 45 N, and the resistance change rate after humid heat and energization exceeded 22%. The initial resistance of Comparative Example 3 (without conductive reinforcing filler) reached 8.0 mΩ. The resistance change rate of Comparative Example 4 (without ion scavenger and corrosion inhibitor) increased significantly after humid heat, salt spray, and energized storage. The initial pull-out force of Comparative Example 5 (without coupling agent) was only 55 N, and local debonding occurred after temperature cycling. The above results demonstrate that the present invention, through the synergistic combination of low-bismuth tin-based microalloy particles, conductive reinforcing fillers, thermosetting flux resins, latent curing agents, reactive activators, glass / metal amphiphilic coupling agents, ion trapping agents, corrosion inhibitors, toughening agents, thixotropic agents, hydrophobic systems, defoamers, leveling agents, and storage stabilizers, achieves high pull-out force, low resistivity change rate, and excellent long-term reliability under conditions where the Bi content is less than 10%, which is significantly superior to the comparative examples.

[0092] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A low-bismuth tin adhesive composite conductive bonding material, characterized in that, The ingredients include the following parts by weight: The composition includes 55-82 parts of low bismuth-tin-based microalloy particles, 3-25 parts of conductive reinforcing filler, 8-28 parts of thermosetting soldering resin, 0.3-6 parts of latent curing agent, 0.2-5 parts of reactive activator, 0.1-4 parts of glass / metal amphiphilic coupling agent, 0.1-5 parts of ion scavenger, 0.05-3 parts of corrosion inhibitor, 0.5-8 parts of toughening agent, and 0.05-3 parts of defoamer.

2. The low-bismuth tin adhesive composite conductive bonding material according to claim 1, characterized in that, The low-bismuth tin-based microalloyed particles include Sn, and also include one or more of In, Ag, Cu, Ni, Sb, Ge, Zn or Bi; The mass fraction of Bi in the low bismuth-tin-based microalloyed particles is <10%.

3. The low-bismuth tin adhesive composite conductive bonding material according to claim 1, characterized in that, The conductive reinforcing filler includes one or more of the following: flake silver powder, spherical silver powder, silver-coated copper powder, tin-coated copper powder, silver-coated nickel powder, nickel powder, copper powder, graphene-silver composite powder, and silver nanowires.

4. The low-bismuth tin adhesive composite conductive bonding material according to claim 1, characterized in that, The thermosetting flux resin includes one or more of the following: bisphenol F epoxy resin, bisphenol A epoxy resin, alicyclic epoxy resin, phenolic resin, polyurethane modified epoxy resin, siloxane modified epoxy resin, maleimide resin, benzoxazine resin, and epoxy-phenolic resin system. The latent curing agent includes one or more of dicyandiamide, modified imidazole, microencapsulated imidazole, aromatic amine salts, acid anhydride microcapsules, blocked isocyanates, and boronamine complexes.

5. The low-bismuth tin adhesive composite conductive bonding material according to claim 1, characterized in that, The reactive activator includes one or more of the following: carboxyl-terminated polyester, carboxyl-modified epoxy, hydroxycarboxylic acid, phosphate ester, imidazole carboxylate, mercaptocarboxylic acid derivative, acid anhydride compound, or organic acid containing epoxy reactive group.

6. The low-bismuth tin adhesive composite conductive bonding material according to claim 1, characterized in that, The glass / metal amphiphilic coupling agent includes silane coupling agents and metal affinity coupling agents; The silane coupling agent includes one of epoxy silane, amino silane, mercapto silane, methacryloxy silane, and alkoxy silane oligomers; The metal affinity coupling agent may be selected from one of the following: phosphate ester, titanate ester, zirconate ester, mercaptotriazine, and reactive compounds containing a benzotriazole structure.

7. The low-bismuth tin adhesive composite conductive bonding material according to claim 1, characterized in that, The ion scavenging agent includes one or more of the following: hydrotalcite, modified hydrotalcite, zeolite, zirconium phosphate, layered double hydroxide, ion exchange resin micro powder, and alumina silicate. The corrosion inhibitor is one or more of the following: benzotriazole, methylbenzotriazole, mercaptobenzothiazole, mercaptotriazine, imidazole derivatives, organophosphates, and molybdate microcapsules.

8. A method for preparing a low-bismuth tin adhesive composite conductive bonding material as described in any one of claims 1-7, characterized in that, Includes the following steps: After adding the toughening agent to the mother liquor of the thermosetting flux resin, a latent curing agent, a reactive activator, a glass / metal amphiphilic coupling agent, an ion scavenger, a corrosion inhibitor, and a defoamer are added and dispersed evenly. Then, conductive reinforcing fillers are added in batches to the resulting mixture and stirred and dispersed. Finally, low bismuth tin-based microalloy particles are added, stirred, ground, and dispersed to obtain the low bismuth tin adhesive composite conductive bonding material.

9. The application of a low-bismuth tin adhesive composite conductive bonding material as described in any one of claims 1-7 in glass metallization bonding.

10. A method for metallizing glass, characterized in that, Includes the following steps: Using the low-bismuth tin adhesive composite conductive bonding material according to any one of claims 1-7, the metal terminal and the glass coating surface are bonded together to obtain a bonded part. The bonded part is then cured at 160-170°C for 10-13 minutes to complete the glass metallization connection.

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