Silver paste for vehicle-mounted glass antenna and production process thereof

Abstract

The invention discloses silver paste for a vehicle-mounted glass antenna and a production process of the silver paste. The silver paste is composed of silane coupling agent surface modified composite silver powder, composite lead-free glass powder, an organic carrier and a multifunctional composite additive. The composite silver powder is formed by compounding flaky silver powder, spherical silver powder and silver nanowires according to the ratio of 4: (1-3): (0.5-0.8), and the composite lead-free glass powder contains La2O3-CeO2 rare earth oxide and Nb2O5, TiO2, HfO2 and Ta2O5 multi-element modified components. The production process comprises the steps of silver powder surface modification, glass powder pre-sintering activation, mixed grinding, vacuum curing and graded filtering. According to the silver paste, through multi-component collaborative design, the sheet resistance is as low as 0.1 mm line width printing reject ratio is 1.0%, the resistance change rate is only 1.3% when the silver paste is subjected to 85 DEG C / 85% RH damp-heat aging for 1000 h, the adhesive force reaches grade 0, and the silver paste is environmentally friendly and free of lead.

Description

Technical Field

[0001] This invention relates to the field of electronic paste technology, and in particular to a silver paste for automotive glass antennas and its manufacturing process. Background Technology

[0002] With the rapid development of automotive electrification, intelligence, and connectivity, automotive glass has evolved from its traditional function of providing shelter from the elements to multifunctional integration, giving rise to new products such as 5G antenna glass, ETC antenna glass, and V2X vehicle-to-everything (V2X) antenna glass. Silver paste, used as the core conductive material in automotive glass antennas, directly determines the antenna's signal reception efficiency, reliability, and lifespan. This silver paste requires screen printing technology to form a high-precision antenna pattern on the glass surface, and after sintering, it achieves good conductivity, a stable bond with the glass substrate, and weather resistance in extreme environments.

[0003] Currently, the global market for silver paste for automotive glass antennas is mainly monopolized by international giants such as DuPont and Heraeus. While their products offer excellent performance, they are also expensive and subject to core technology blockades. Although domestic companies have made breakthroughs in the field of silver paste for automotive glass antennas, they still have significant shortcomings: First, insufficient printing precision makes it difficult to meet the ultra-fine linewidth printing requirements of scenarios such as HUD head-up displays and smart dimming glass, resulting in easy diffusion and breakage of lines at the edges; second, insufficient interfacial bonding strength, with poor matching of the thermal expansion coefficients between the silver paste and the glass substrate, easily generating internal stress during temperature cycling, leading to coating cracking and peeling; third, environmental performance needs improvement, with some products still containing harmful substances such as lead; and fourth, poor overall performance balance, with conductivity, weather resistance, and solderability failing to simultaneously meet the requirements of high-end automotive antennas.

[0004] To address the aforementioned problems, invention patent application CN117690630A discloses a high-thickness conductive silver paste for GPS ceramic antennas, its preparation method, and its application. The raw materials consist of the following components and weight percentages: 75%–85% conductive silver powder, 2%–4% organic binder, 3%–5% inorganic binder, 8%–18% solvent, and 0.5%–1.5% additives. The conductive silver powder is spherical, and the D50 particle size of the conductive silver powder is... The organic binder includes one or more of ethyl cellulose, nitrocellulose, rosin, ethyl hydroxyethyl cellulose, and acrylic resin; the inorganic binder is lead-free glass powder with a D50 particle size of... Compared with existing technologies, this invention has a higher viscosity and thicker conductive silver paste. The solder joints did not detach, and the welding strength was significantly enhanced. Furthermore, the welding problems caused by "silver absorption" in small components were improved, resulting in better adaptability. However, this invention is designed for GPS ceramic antenna applications and does not consider the precision requirements of ultra-fine linewidth printing for automotive glass antennas, the need for precise matching of the thermal expansion coefficient with the glass substrate, and the long-term weather resistance and anti-ion migration performance under harsh temperature and humidity environments. Therefore, it is difficult to adapt to the multi-functional integrated application scenarios of high-end automotive glass antennas such as 5G / MIMO and V2X.

[0005] Therefore, developing a silver paste for automotive glass antennas that balances printing accuracy, conductivity, adhesion, weather resistance, and environmental friendliness is crucial to breaking the foreign monopoly and promoting the development of the domestic automotive glass antenna industry. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a silver paste for automotive glass antennas and its manufacturing process. Through multi-component synergistic innovation and process optimization, it solves technical problems such as low printing precision, unstable interface bonding, thermal expansion mismatch, and poor environmental performance of existing silver pastes, achieving a unified solution of high-precision printing, high conductivity, high weather resistance, and environmentally friendly lead-free properties.

[0007] To achieve the above objectives, the technical solution adopted by this invention is: a silver paste for vehicle-mounted glass antennas, comprising the following components by weight: 70-80 parts of silane coupling agent surface-modified composite silver powder, 5-10 parts of composite lead-free glass powder, 10-20 parts of organic carrier, and 1-3 parts of multifunctional composite additive; the composite silver powder is a mixture of flake silver powder, spherical silver powder, and silver nanowires in a weight ratio of 4:(1-3):(0.5-0.8); the chemical composition of the composite lead-free glass powder by weight is: 32-38 parts of B2O3, 28-34 parts of SiO2, 18-24 parts of ZnO, 6-9 parts of Al2O3, 3-5 parts of MgO, 1-3 parts of rare earth oxides, 0.5-1.5 parts of Nb2O5, 1-3 parts of TiO2, 0.3-1.2 parts of HfO2, and 0.5-1.5 parts of Ta2O5. 0.1-0.5 portions.

[0008] Preferably, the rare earth oxide is a mixture of La2O3 and CeO2 in a mass ratio of 2:1.

[0009] Preferably, the silane coupling agent is at least one of silane coupling agent KH550, silane coupling agent KH560, and silane coupling agent KH570.

[0010] Preferably, the particle size of the flake silver powder is [missing information]. The particle size of the spherical silver powder is... The diameter of the silver nanowires is 100-150 nm.

[0011] Preferably, the organic carrier is composed of the following components in parts by weight: 12-20 parts of composite resin, 65-78 parts of mixed solvent, 6-12 parts of composite rheology modifier, 3-6 parts of dispersant, and 1-3 parts of film-forming aid.

[0012] Preferably, the composite resin is a mixture of ethyl cellulose, polyvinyl acetate, and polyvinyl butyral resin in a weight ratio of 3:2:1.

[0013] Preferably, the polyvinyl acetate has a weight-average molecular weight of 50,000; and the polyvinyl butyral resin has a weight-average molecular weight of 20,000.

[0014] Preferably, the mixed solvent is a mixture of terpineol, ethylene glycol ethyl ether acetate, and diethylene glycol butyl ether acetate in a weight ratio of 4:3:1.

[0015] Preferably, the composite rheology modifier is a mixture of hydrogenated castor oil, nano-montmorillonite, and polyamide wax in a weight ratio of 2:1:1.

[0016] Preferably, the nano-montmorillonite is DK0 polymer-grade nano-montmorillonite.

[0017] Preferably, the dispersant is a compound of BYK-110, BYK-163 and BYK-2000 in a weight ratio of 1:1:0.5; and the film-forming aid is polyethylene glycol monomethyl ether 2000.

[0018] Preferably, the multifunctional composite additive is a mixture of ZrO2 and La2O3 in a weight ratio of (2-3):1; the average particle size of the multifunctional composite additive is 50-100 nm.

[0019] Another object of the present invention is to provide a manufacturing process for the silver paste used in the vehicle-mounted glass antenna, comprising the following steps: Step S1: Add composite silver powder to ethanol, ultrasonically disperse for 30 min, add silane coupling agent at 0.5-1.0% of the weight of composite silver powder, stir and react for 2 h at 60-70℃ and 300 r / min, filter, vacuum dry at 80℃ for 4 h, and obtain silane coupling agent surface modified composite silver powder. Step S2: Mix the components of the composite lead-free glass powder according to the weight parts, pre-sinter and activate at 500-550℃ for 1 hour, cool and then pulverize to the particle size specified in step S2. A composite lead-free glass powder was obtained; Step S3: Mix the silane coupling agent surface-modified composite silver powder, composite lead-free glass powder, organic carrier, and multifunctional composite additive evenly, and then grind, mature, filter through a 300-mesh stainless steel filter, and then filter through a 5μm fine filter membrane before bottling and sealing.

[0020] Preferably, the curing in step S3 specifically refers to curing at 25°C in a vacuum environment for 24 hours.

[0021] Due to the application of the above technical solution, the present invention has the following beneficial effects: (1) The silver paste for vehicle-mounted glass antennas disclosed in this invention adopts a ternary composite system of flake silver powder, spherical silver powder and silver nanowires, combined with surface modification by silane coupling agent. The silver nanowires can bridge the gaps in the conductive skeleton formed by the flake and spherical silver powders to construct a "three-dimensional interwoven" conductive network, which significantly improves the conductivity efficiency compared with existing single-morphology or binary composite silver powders. At the same time, the dispersion stability of the ternary silver powder is significantly enhanced after modification. Combined with the organic carrier controlled by the composite rheology modifier, the paste has excellent thixotropic and leveling properties, which can stably achieve ultra-fine linewidth printing with low printing defect rate, and completely solves the technical bottleneck of existing silver pastes that "high conductivity and high precision printing are difficult to achieve simultaneously".

[0022] (2) The silver paste for automotive glass antennas disclosed in this invention, through the multi-element synergistic design of rare earth oxides (La2O3, CeO2), HfO2, Ta2O5 and Nb2O5, TiO2, not only precisely controls the coefficient of thermal expansion to achieve a high match with the automotive glass substrate, thus significantly reducing the residual stress during sintering; but also through the synergistic effect of La2O3 forming chemical bonds with the glass substrate, TiO2 reducing the interface contact angle, and HfO2 enhancing the mechanical strength, the silver film adhesion reaches level 0 in the cross-cut test, and the impact resistance is significantly improved, thus completely avoiding the hidden dangers of coating cracking and peeling during temperature cycling.

[0023] (3) The silver paste for vehicle-mounted glass antennas disclosed in this invention forms a "triple ion capture system" by combining La2O3, CeO2 and Ta2O5 in lead-free glass powder, which can accurately adsorb Na in the glass substrate. + Ca 2+ Metal ions, combined with ZrO2 to fill the micropores of the silver film, improve the ion migration suppression rate, effectively preventing spots and conductivity attenuation from appearing on the silver film after long-term use, and effectively extending the antenna's service life. At the same time, the paste is designed to be lead-free throughout the process, achieving super strong anti-ion migration performance without sacrificing conductivity or adhesion, breaking the industry dilemma of "performance compromise" in existing environmentally friendly silver pastes.

[0024] (4) The silver paste for automotive glass antennas disclosed in this invention achieves simultaneous compliance with six core performance standards: high precision printing, high conductivity, high adhesion, high weather resistance, strong resistance to ion migration, and environmentally friendly lead-free properties through multi-dimensional synergistic design of each component (silver powder compounding + glass phase modification + carrier regulation + additive synergy). This completely breaks the balance relationship in the existing technology where "optimization of a single performance inevitably leads to the degradation of other performances." At the same time, the production process adopts optimized steps such as vacuum curing and graded filtration, resulting in strong paste stability and high yield in industrial production. While meeting the needs of high-end automotive antennas such as 5G / MIMO and V2X, it also has strong market competitiveness, providing core support for the domestic substitution of silver paste for automotive glass antennas. Detailed Implementation

[0025] The following description is intended to disclose the invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art. Example 1

[0026] A silver paste for automotive glass antennas comprises the following components in parts by weight: 70 parts of silane coupling agent surface-modified composite silver powder, 5 parts of composite lead-free glass powder, 10 parts of organic carrier, and 1 part of multifunctional composite additive; the composite silver powder is a mixture of flake silver powder, spherical silver powder, and silver nanowires in a weight ratio of 4:1:0.5; the chemical composition of the composite lead-free glass powder in parts by weight is: 32 parts B2O3, 28 parts SiO2, 18 parts ZnO, 6 parts Al2O3, 3 parts MgO, 1 part rare earth oxide, 0.5 parts Nb2O5, 1 part TiO2, 0.3 parts HfO2, and 0.1 parts Ta2O5.

[0027] The rare earth oxide is a mixture of La2O3 and CeO2 in a mass ratio of 2:1; the silane coupling agent is silane coupling agent KH550; the particle size of the flake silver powder is [missing information]. The particle size of the spherical silver powder is... The silver nanowires have a diameter of 100-150 nm. The synergistic organic carrier is composed of the following components by weight: 12 parts composite resin, 65 parts mixed solvent, 6 parts composite rheology modifier, 3 parts dispersant, and 1 part film-forming aid. The composite resin is a mixture of ethyl cellulose, polyvinyl acetate, and polyvinyl butyral resin in a weight ratio of 3:2:1. The polyvinyl acetate has a weight-average molecular weight of 50,000, and the polyvinyl butyral resin has a weight-average molecular weight of 20,000. The mixed solvent is terpineol, ethylene glycol ethyl ether acetate, and diethylene glycol butyl ether acetate. The esters are compounded in a weight ratio of 4:3:1; the composite rheology modifier is compounded in a weight ratio of 2:1:1 of hydrogenated castor oil, nano-montmorillonite, and polyamide wax; the nano-montmorillonite is DK0 polymer-grade nano-montmorillonite; the dispersant is compounded in a weight ratio of 1:1:0.5 of BYK-110, BYK-163, and BYK-2000; the film-forming aid is polyethylene glycol monomethyl ether 2000; the multifunctional composite additive is compounded in a weight ratio of 2:1 of ZrO2 and La2O3; the average particle size of the multifunctional composite additive is 50 nm.

[0028] A manufacturing process for the silver paste used in the vehicle-mounted glass antenna includes the following steps: Step S1: Add composite silver powder to ethanol, ultrasonically disperse for 30 min, add silane coupling agent at 0.5% of the weight of composite silver powder, stir and react for 2 h at 60℃ and 300 r / min, filter, vacuum dry at 80℃ for 4 h, and obtain silane coupling agent surface modified composite silver powder. Step S2: Mix the components of the composite lead-free glass powder according to the weight parts, pre-sinter and activate at 500℃ for 1 hour, cool, and then pulverize to the specified particle size. A composite lead-free glass powder was obtained; Step S3: Mix the silane coupling agent surface-modified composite silver powder, composite lead-free glass powder, organic carrier, and multifunctional composite additive evenly, and then grind, mature, filter through a 300-mesh stainless steel filter, and then filter through a 5μm fine filter membrane. Bottle and seal. The maturation is specifically carried out at 25°C in a vacuum environment for 24 hours. Example 2

[0029] A silver paste for automotive glass antennas comprises the following components in parts by weight: 73 parts of silane coupling agent surface-modified composite silver powder, 6 parts of composite lead-free glass powder, 13 parts of organic carrier, and 1.5 parts of multifunctional composite additive; the composite silver powder is a mixture of flake silver powder, spherical silver powder, and silver nanowires in a weight ratio of 4:1.5:0.6; the chemical composition of the composite lead-free glass powder in parts by weight is: 33 parts B2O3, 29 parts SiO2, 20 parts ZnO, 7 parts Al2O3, 3.5 parts MgO, 1.5 parts rare earth oxides, 0.7 parts Nb2O5, 1.5 parts TiO2, 0.5 parts HfO2, and 0.2 parts Ta2O5.

[0030] The rare earth oxide is a mixture of La2O3 and CeO2 in a mass ratio of 2:1; the silane coupling agent is silane coupling agent KH560; the particle size of the flake silver powder is [missing information]. The particle size of the spherical silver powder is... The silver nanowires have a diameter of 100-150 nm. The synergistic organic carrier is composed of the following components by weight: 14 parts composite resin, 68 parts mixed solvent, 8 parts composite rheology modifier, 4 parts dispersant, and 1.5 parts film-forming aid. The composite resin is a mixture of ethyl cellulose, polyvinyl acetate, and polyvinyl butyral resin in a weight ratio of 3:2:1. The polyvinyl acetate has a weight-average molecular weight of 50,000, and the polyvinyl butyral resin has a weight-average molecular weight of 20,000. The mixed solvent is terpineol, ethylene glycol ethyl ether acetate, and diethylene glycol butyl ether acetate. The esters are compounded in a weight ratio of 4:3:1; the composite rheology modifier is compounded in a weight ratio of 2:1:1 of hydrogenated castor oil, nano-montmorillonite, and polyamide wax; the nano-montmorillonite is DK0 polymer-grade nano-montmorillonite; the dispersant is compounded in a weight ratio of 1:1:0.5 of BYK-110, BYK-163, and BYK-2000; the film-forming aid is polyethylene glycol monomethyl ether 2000; the multifunctional composite additive is compounded in a weight ratio of 2.3:1 of ZrO2 and La2O3; the average particle size of the multifunctional composite additive is 70 nm.

[0031] A manufacturing process for the silver paste used in the vehicle-mounted glass antenna includes the following steps: Step S1: Add composite silver powder to ethanol, ultrasonically disperse for 30 min, add silane coupling agent at 0.7% of the weight of composite silver powder, stir and react for 2 h at 63℃ and 300 r / min, filter, vacuum dry at 80℃ for 4 h, and obtain silane coupling agent surface modified composite silver powder. Step S2: Mix the components of the composite lead-free glass powder according to the weight parts, pre-sinter and activate at 520℃ for 1 hour, cool, and then pulverize to the specified particle size. A composite lead-free glass powder was obtained; Step S3: Mix the silane coupling agent surface-modified composite silver powder, composite lead-free glass powder, organic carrier, and multifunctional composite additive evenly, and then grind, mature, filter through a 300-mesh stainless steel filter, and then filter through a 5μm fine filter membrane. Bottle and seal. The maturation is specifically carried out at 25°C in a vacuum environment for 24 hours. Example 3

[0032] A silver paste for automotive glass antennas comprises the following components in parts by weight: 75 parts of silane coupling agent surface-modified composite silver powder, 8 parts of composite lead-free glass powder, 15 parts of organic carrier, and 2 parts of multifunctional composite additive; the composite silver powder is a mixture of flake silver powder, spherical silver powder, and silver nanowires in a weight ratio of 4:2:0.65; the chemical composition of the composite lead-free glass powder in parts by weight is: 35 parts B2O3, 31 parts SiO2, 21 parts ZnO, 7.5 parts Al2O3, 4 parts MgO, 2 parts rare earth oxides, 1 part Nb2O5, 2 parts TiO2, 0.8 parts HfO2, and 0.3 parts Ta2O5.

[0033] The rare earth oxide is a mixture of La2O3 and CeO2 in a mass ratio of 2:1; the silane coupling agent is silane coupling agent KH560; the particle size of the flake silver powder is [missing information]. The particle size of the spherical silver powder is... The silver nanowires have a diameter of 100-150 nm. The synergistic organic carrier is composed of the following components by weight: 16 parts composite resin, 71 parts mixed solvent, 9 parts composite rheology modifier, 4.5 parts dispersant, and 2 parts film-forming aid. The composite resin is a mixture of ethyl cellulose, polyvinyl acetate, and polyvinyl butyral resin in a weight ratio of 3:2:1. The polyvinyl acetate has a weight-average molecular weight of 50,000, and the polyvinyl butyral resin has a weight-average molecular weight of 20,000. The mixed solvent is terpineol, ethylene glycol ethyl ether acetate, and diethylene glycol butyl ether acetate. The esters are compounded in a weight ratio of 4:3:1; the composite rheology modifier is compounded in a weight ratio of 2:1:1 of hydrogenated castor oil, nano-montmorillonite, and polyamide wax; the nano-montmorillonite is DK0 polymer-grade nano-montmorillonite; the dispersant is compounded in a weight ratio of 1:1:0.5 of BYK-110, BYK-163, and BYK-2000; the film-forming aid is polyethylene glycol monomethyl ether 2000; the multifunctional composite additive is compounded in a weight ratio of 2.5:1 of ZrO2 and La2O3; the average particle size of the multifunctional composite additive is 80 nm.

[0034] A manufacturing process for the silver paste used in the vehicle-mounted glass antenna includes the following steps: Step S1: Add composite silver powder to ethanol, ultrasonically disperse for 30 min, add silane coupling agent at 0.8% of the weight of composite silver powder, stir and react for 2 h at 65℃ and 300 r / min, filter, vacuum dry at 80℃ for 4 h, and obtain silane coupling agent surface modified composite silver powder. Step S2: Mix the components of the composite lead-free glass powder according to the weight parts, pre-sinter and activate at 530℃ for 1 hour, cool, and then pulverize to the specified particle size. A composite lead-free glass powder was obtained; Step S3: Mix the silane coupling agent surface-modified composite silver powder, composite lead-free glass powder, organic carrier, and multifunctional composite additive evenly, and then grind, mature, filter through a 300-mesh stainless steel filter, and then filter through a 5μm fine filter membrane. Bottle and seal. The maturation is specifically carried out at 25°C in a vacuum environment for 24 hours. Example 4

[0035] A silver paste for automotive glass antennas comprises the following components in parts by weight: 78 parts of silane coupling agent surface-modified composite silver powder, 9 parts of composite lead-free glass powder, 18 parts of organic carrier, and 2.5 parts of multifunctional composite additive; the composite silver powder is a mixture of flake silver powder, spherical silver powder, and silver nanowires in a weight ratio of 4:2.5:0.75; the chemical composition of the composite lead-free glass powder in parts by weight is: 37 parts B2O3, 33 parts SiO2, 23 parts ZnO, 8.5 parts Al2O3, 4.5 parts MgO, 2.5 parts rare earth oxides, 1.3 parts Nb2O5, 2.5 parts TiO2, 1 part HfO2, and 0.4 parts Ta2O5.

[0036] The rare earth oxide is a mixture of La2O3 and CeO2 in a mass ratio of 2:1; the silane coupling agent is a mixture of silane coupling agents KH550, KH560, and KH570 in a mass ratio of 1:2:3; the particle size of the flake silver powder is... The particle size of the spherical silver powder is... The silver nanowires have a diameter of 100-150 nm. The synergistic organic carrier is composed of the following components by weight: 18 parts composite resin, 76 parts mixed solvent, 11 parts composite rheology modifier, 5.5 parts dispersant, and 2.5 parts film-forming aid. The composite resin is a mixture of ethyl cellulose, polyvinyl acetate, and polyvinyl butyral resin in a weight ratio of 3:2:1. The polyvinyl acetate has a weight-average molecular weight of 50,000, and the polyvinyl butyral resin has a weight-average molecular weight of 20,000. The mixed solvent is terpineol, ethylene glycol ethyl ether acetate, and diethylene glycol butylene acetate. The ether acetate is compounded in a weight ratio of 4:3:1; the composite rheology modifier is compounded in a weight ratio of 2:1:1 of hydrogenated castor oil, nano-montmorillonite, and polyamide wax; the nano-montmorillonite is DK0 polymer-grade nano-montmorillonite; the dispersant is compounded in a weight ratio of 1:1:0.5 of BYK-110, BYK-163, and BYK-2000; the film-forming aid is polyethylene glycol monomethyl ether 2000; the multifunctional composite additive is compounded in a weight ratio of 2.8:1 of ZrO2 and La2O3; the average particle size of the multifunctional composite additive is 90 nm.

[0037] A manufacturing process for the silver paste used in the vehicle-mounted glass antenna includes the following steps: Step S1: Add composite silver powder to ethanol, ultrasonically disperse for 30 min, add silane coupling agent at 0.9% of the weight of composite silver powder, stir and react for 2 h at 68℃ and 300 r / min, filter, vacuum dry at 80℃ for 4 h, and obtain silane coupling agent surface modified composite silver powder. Step S2: Mix the components of the composite lead-free glass powder according to the weight parts, pre-sinter and activate at 540℃ for 1 hour, cool, and then pulverize to the specified particle size. A composite lead-free glass powder was obtained; Step S3: Mix the silane coupling agent surface-modified composite silver powder, composite lead-free glass powder, organic carrier, and multifunctional composite additive evenly, and then grind, mature, filter through a 300-mesh stainless steel filter, and then filter through a 5μm fine filter membrane. Bottle and seal. The maturation is specifically carried out at 25°C in a vacuum environment for 24 hours. Example 5

[0038] A silver paste for automotive glass antennas comprises the following components in parts by weight: 80 parts of silane coupling agent surface-modified composite silver powder, 10 parts of composite lead-free glass powder, 20 parts of organic carrier, and 3 parts of multifunctional composite additive; the composite silver powder is a mixture of flake silver powder, spherical silver powder, and silver nanowires in a weight ratio of 4:3:0.8; the chemical composition of the composite lead-free glass powder in parts by weight is: 38 parts B2O3, 34 parts SiO2, 24 parts ZnO, 9 parts Al2O3, 5 parts MgO, 3 parts rare earth oxides, 1.5 parts Nb2O5, 3 parts TiO2, 1.2 parts HfO2, and 0.5 parts Ta2O5.

[0039] The rare earth oxide is a mixture of La2O3 and CeO2 in a mass ratio of 2:1; the silane coupling agent is silane coupling agent KH550; the particle size of the flake silver powder is [missing information]. The particle size of the spherical silver powder is... The silver nanowires have a diameter of 100-150 nm. The synergistic organic carrier is composed of the following components by weight: 20 parts composite resin, 78 parts mixed solvent, 12 parts composite rheology modifier, 6 parts dispersant, and 3 parts film-forming aid. The composite resin is a mixture of ethyl cellulose, polyvinyl acetate, and polyvinyl butyral resin in a weight ratio of 3:2:1. The polyvinyl acetate has a weight-average molecular weight of 50,000, and the polyvinyl butyral resin has a weight-average molecular weight of 20,000. The mixed solvent is terpineol, ethylene glycol ethyl ether acetate, and diethylene glycol butyl ether acetate. The esters are compounded in a weight ratio of 4:3:1; the composite rheology modifier is compounded in a weight ratio of 2:1:1 of hydrogenated castor oil, nano-montmorillonite, and polyamide wax; the nano-montmorillonite is DK0 polymer-grade nano-montmorillonite; the dispersant is compounded in a weight ratio of 1:1:0.5 of BYK-110, BYK-163, and BYK-2000; the film-forming aid is polyethylene glycol monomethyl ether 2000; the multifunctional composite additive is compounded in a weight ratio of 3:1 of ZrO2 and La2O3; the average particle size of the multifunctional composite additive is 100 nm.

[0040] A manufacturing process for the silver paste used in the vehicle-mounted glass antenna includes the following steps: Step S1: Add composite silver powder to ethanol, ultrasonically disperse for 30 min, add silane coupling agent at 1.0% of the weight of composite silver powder, stir and react for 2 h at 70℃ and 300 r / min, filter, vacuum dry at 80℃ for 4 h, and obtain silane coupling agent surface modified composite silver powder. Step S2: Mix the components of the composite lead-free glass powder according to the weight parts, pre-sinter and activate at 550℃ for 1 hour, cool, and then pulverize to the specified particle size. A composite lead-free glass powder was obtained; Step S3: Mix the silane coupling agent surface-modified composite silver powder, composite lead-free glass powder, organic carrier, and multifunctional composite additive evenly, and then grind, mature, filter through a 300-mesh stainless steel filter, and then filter through a 5μm fine filter membrane. Bottle and seal. The maturation is specifically carried out at 25℃ in a vacuum environment for 24 hours.

[0041] Comparative Example 1 A silver paste for vehicle-mounted glass antennas and its manufacturing process are basically the same as those in Example 5, except that an equal amount of spherical silver powder is used instead of silver nanowires.

[0042] Comparative Example 2 A silver paste for vehicle-mounted glass antennas and its manufacturing process are basically the same as those in Example 5, except that an equal amount of Nb2O5 is used instead of HfO2.

[0043] Comparative Example 3 A silver paste for vehicle-mounted glass antennas and its manufacturing process are basically the same as those in Example 5, except that an equal amount of HfO2 is used instead of Nb2O5.

[0044] Comparative Example 4 A silver paste for vehicle-mounted glass antennas and its manufacturing process are basically the same as those in Example 5, except that Ta2O5 is not added.

[0045] To further illustrate the beneficial technical effects of the various embodiments of the present invention, the products of Example 5 and Comparative Examples 1-4 were subjected to relevant performance tests according to current Chinese standards. The test results are shown in Table 1, and the test methods are as follows: (1) Sheet resistance: The sheet resistance was tested using a four-probe sheet resistance meter (RTS-9) and sintered at 160℃ for 2.5 min. (2) Printing performance test: 300 mesh screen with a printing line width of 0.1 mm was used to test the printing defect rate (the proportion of defects such as broken lines, diffusion, and pinholes). (3) Resistance to damp heat aging: Each product was aged at 85℃ / 85% RH for 1000h, and the resistance change rate after aging was calculated.

[0046] (4) Adhesion: Cross-cut tester, GB / T 9286-1998, cross-cut spacing 1mm, tape peel test.

[0047] Table 1 Performance Test Results Table 1 shows that Example 5, through the ternary composite of silver nanowires and sheet-like and spherical silver powder, and the multi-component synergistic modification design of HfO2, Nb2O5, and Ta2O5 in the composite lead-free glass powder, significantly outperforms Comparative Examples 1-4 in all core performance aspects: its sheet resistance is as low as The printing defect rate was only 1.0%, and the resistance change rate after 1000 hours of humid heat aging at 85℃ / 85% RH was only 1.3%, with adhesion reaching grade 0. In contrast, Comparative Example 1 suffered from insufficient density of the conductive network due to the lack of silver nanowires, and Comparative Examples 2-4 suffered from weakened functions such as interface bonding and ion migration inhibition due to the lack of HfO2, Nb2O5 or Ta2O5 alone. All of them showed problems such as increased sheet resistance, increased printing defects, decreased aging stability and adhesion down to grade 1, which fully demonstrates the technical superiority of the multi-component synergistic design of this invention.

[0048] The above embodiments are only for illustrating the technical concept and features of the present invention. Their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A silver paste for vehicle-mounted glass antennas, characterized in that, It is made from the following components by weight: 70-80 parts of silane coupling agent surface-modified composite silver powder, 5-10 parts of composite lead-free glass powder, 10-20 parts of organic carrier, and 1-3 parts of multifunctional composite additive; the composite silver powder is a mixture of flake silver powder, spherical silver powder and silver nanowires in a weight ratio of 4:(1-3):(0.5-0.8); the chemical composition of the composite lead-free glass powder by weight is: 32-38 parts of B2O3, 28-34 parts of SiO2, 18-24 parts of ZnO, 6-9 parts of Al2O3, 3-5 parts of MgO, 1-3 parts of rare earth oxides, 0.5-1.5 parts of Nb2O5, 1-3 parts of TiO2, 0.3-1.2 parts of HfO2, and 0.1-0.5 parts of Ta2O5.

2. The silver paste for vehicle-mounted glass antennas according to claim 1, characterized in that, The rare earth oxide is a mixture of La2O3 and CeO2 in a mass ratio of 2:

1.

3. The silver paste for vehicle-mounted glass antennas according to claim 1, characterized in that, The silane coupling agent is at least one of silane coupling agent KH550, silane coupling agent KH560, and silane coupling agent KH570.

4. The silver paste for vehicle-mounted glass antennas according to claim 1, characterized in that, The particle size of the flake-shaped silver powder is The particle size of the spherical silver powder is... The diameter of the silver nanowires is 100-150 nm.

5. The silver paste for vehicle-mounted glass antennas according to claim 1, characterized in that, The organic carrier is composed of the following components by weight: 12-20 parts of composite resin, 65-78 parts of mixed solvent, 6-12 parts of composite rheology modifier, 3-6 parts of dispersant, and 1-3 parts of film-forming aid.

6. The silver paste for vehicle-mounted glass antennas according to claim 5, characterized in that, The composite resin is composed of ethyl cellulose, polyvinyl acetate, and polyvinyl butyral resin in a weight ratio of 3:2:1; the weight average molecular weight of the polyvinyl acetate is 50,000; and the weight average molecular weight of the polyvinyl butyral resin is 20,000.

7. The silver paste for vehicle-mounted glass antennas according to claim 5, characterized in that, The mixed solvent is composed of terpineol, ethylene glycol ethyl ether acetate, and diethylene glycol butyl ether acetate in a weight ratio of 4:3:1; the composite rheology modifier is composed of hydrogenated castor oil, nano-montmorillonite, and polyamide wax in a weight ratio of 2:1:1; the nano-montmorillonite is DK0 polymer-grade nano-montmorillonite.

8. The silver paste for vehicle-mounted glass antennas according to claim 5, characterized in that, The dispersant is a compound of BYK-110, BYK-163 and BYK-2000 in a weight ratio of 1:1:0.5; the film-forming aid is polyethylene glycol monomethyl ether 2000.

9. The silver paste for vehicle-mounted glass antennas according to claim 1, characterized in that, The multifunctional composite additive is composed of ZrO2 and La2O3 in a weight ratio of (2-3):1; the average particle size of the multifunctional composite additive is 50-100 nm.

10. A manufacturing process for silver paste for automotive glass antennas according to any one of claims 1-9, characterized in that, Includes the following steps: Step S1: Add composite silver powder to ethanol, ultrasonically disperse for 30 min, add silane coupling agent at 0.5-1.0% of the weight of composite silver powder, stir and react for 2 h at 60-70℃ and 300 r / min, filter, vacuum dry at 80℃ for 4 h, and obtain silane coupling agent surface modified composite silver powder. Step S2: Mix the components of the composite lead-free glass powder according to the weight parts, pre-sinter and activate at 500-550℃ for 1 hour, cool, and then pulverize to the specified particle size. A composite lead-free glass powder was obtained; Step S3: Mix the silane coupling agent surface-modified composite silver powder, composite lead-free glass powder, organic carrier, and multifunctional composite additive evenly, and then grind, mature, filter through a 300-mesh stainless steel filter, and then filter through a 5μm fine filter membrane. Bottle and seal. The maturation is specifically carried out at 25°C in a vacuum environment for 24 hours.

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