A copper electronic paste for glass-based printed circuits and a method for preparing the same

Abstract

This invention belongs to the field of printed circuit technology and provides a copper electronic paste for glass-based printed circuits and its preparation method. The copper electronic paste for glass-based printed circuits includes composite modified copper powder, modified glass powder, and an organic carrier. The composite modified copper powder is composed of modified spherical copper powder and modified flake copper powder. The modified spherical copper powder is obtained by modifying spherical copper powder with an organic titanate, and the modified flake copper powder is obtained by modifying flake copper powder with a silicate. The modified glass powder is obtained by modifying glass powder with polyethyleneimine and a phosphate coupling agent. The glass powder is obtained by mixing B2O3, Bi2O3, ZnO, SiO2, Al2O3, P2O5, TiO2, ZrO2, La2O3, and MoO3 and then melting, water quenching, drying, and grinding. The organic carrier includes terpineol, butyl carbitol acetate, ethyl cellulose, and a thixotropic agent.

Description

Technical Field

[0001] This invention belongs to the field of printed circuit technology and relates to a copper electronic paste for glass-based printed circuits and its preparation method. Background Technology

[0002] With the rapid development of electronic devices towards thinner, lighter, higher-performance, and more multifunctional designs, glass substrates are attracting increasing attention in the printed circuit field due to their excellent transparency, good dimensional stability, high heat resistance, and low dielectric loss. Compared to traditional organic substrates, glass substrates are particularly suitable for applications with stringent requirements for light transmittance, weather resistance, and high-frequency signal integrity.

[0003] Currently, silver-based pastes are dominant in conductive pastes used for printed circuits due to their excellent conductivity and oxidation resistance. However, the high cost of silver, as a precious metal, severely limits its large-scale application in large-area or low-cost electronic devices. Copper, as an inexpensive metal with conductivity close to that of silver, is an ideal alternative. However, copper particles are highly susceptible to oxidation, forming a non-conductive oxide layer, which significantly impairs the conductivity of the final circuit during paste preparation, storage, and subsequent sintering and curing. Furthermore, glass surfaces are typically inert, resulting in low adhesion strength between glass and metal particles.

[0004] Therefore, the industry urgently needs a new type of copper electronic paste optimized for the characteristics of glass substrates. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a copper electronic paste for glass-based printed circuits and its preparation method, which solves the technical problems of poor film conductivity, insufficient adhesion, and easy cracking and peeling caused by the easy oxidation of copper, poor compatibility between the glass binder phase and copper powder interface, and differences in thermal expansion coefficients in traditional copper pastes.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a copper electronic paste for glass-based printed circuits, the copper electronic paste for glass-based printed circuits comprising composite modified copper powder, modified glass powder and organic carrier;

[0008] The composite modified copper powder is composed of modified spherical copper powder and modified flake copper powder. The modified spherical copper powder is obtained by modifying spherical copper powder with organic titanate, and the modified flake copper powder is obtained by modifying flake copper powder with silicate.

[0009] The modified glass powder is obtained by modifying glass powder with polyethyleneimine and phosphate ester coupling agent. The glass powder is obtained by mixing B2O3, Bi2O3, ZnO, SiO2, Al2O3, P2O5, TiO2, ZrO2, La2O3 and MoO3 and then melting, water quenching, drying and grinding.

[0010] The organic carrier includes terpineol, butyl carbitol acetate, ethyl cellulose, and a thixotropic agent.

[0011] The copper electronic paste provided by this invention consists of a conductive phase, a binder phase, and an organic matrix. The conductive phase comprises spherical copper powder modified with organic titanate and flake copper powder modified with silicate. The binder phase is glass powder modified with polyethyleneimine and a phosphate coupling agent. The organic carrier consists of terpineol, butyl carbitol acetate, ethyl cellulose, and a thixotropic agent, ultimately forming a high-performance copper electronic paste for glass-based printed circuits. The composite modified copper powder effectively inhibits the oxidation and agglomeration of copper powder, ensuring the formation of a dense, low-resistance conductive network after sintering. The modified glass powder enhances the interfacial bonding force with the composite modified copper powder and the glass substrate and matches the coefficient of thermal expansion. The organic carrier provides excellent printability and paste stability. The copper electronic paste provided by this invention solves the technical problems of poor film conductivity, insufficient adhesion, and easy cracking and peeling caused by the easy oxidation of copper, poor interfacial compatibility between glass powder and copper powder, and differences in the coefficient of thermal expansion of traditional copper pastes.

[0012] The composite modified copper powder, serving as the conductive phase, comprises modified spherical copper powder and modified flake copper powder. The modified spherical copper powder forms a dense filler, while the modified flake copper powder spreads and overlaps within the conductive film. The combined use of these two materials results in a denser, lower-resistance conductive film after sintering. Furthermore, this invention employs different modification processes to treat the spherical and flake copper powders. The spherical copper powder is modified with an organotitanate, while the flake copper powder is modified with a silicate. This targeted improvement enhances the surface properties of the different copper powder morphologies, strengthens their dispersion stability in the organic carrier, and forms a protective layer before sintering, effectively inhibiting copper powder oxidation and ensuring high electrical conductivity.

[0013] Using modified glass powder as a binder phase, this invention features a specially designed composition of the glass powder, ultimately yielding a glass powder with a suitable coefficient of thermal expansion and a low softening point. This ensures that the coefficient of thermal expansion matches the glass substrate and enables low-temperature sintering. Furthermore, this invention employs a combination of polyethyleneimine and phosphate coupling agents to modify the glass powder, significantly improving the physicochemical properties of the glass powder surface and greatly enhancing its surface compatibility and interfacial bonding with the composite modified copper powder. During sintering, the molten glass phase fully wets and encapsulates the copper powder particles, forming a strong interfacial bond. This greatly improves the interfacial adhesion between the sintered conductive film and the glass substrate, and avoids internal stress and film cracking caused by differences in coefficients of thermal expansion.

[0014] The organic carrier in copper electronic paste is composed of terpineol, butyl carbitol acetate, ethyl cellulose and thixotropic agent. The organic carrier must not only provide suitable rheological properties to ensure good printing performance, but also have good interfacial compatibility with composite modified copper powder and modified glass powder to ensure the stability of the paste during storage and use, prevent particle agglomeration or sedimentation, and ensure that a uniform and reliable conductive film layer is finally obtained.

[0015] As a preferred embodiment of the present invention, the copper electronic paste for glass-based printed circuits, with a weight fraction of 100 wt%, comprises the following components by mass fraction:

[0016] 70-80 wt% of composite modified copper powder;

[0017] Modified glass powder 2~5wt%;

[0018] Organic carrier 15~25wt%.

[0019] The mass fraction of the composite modified copper powder can be 70wt%, 71wt%, 72wt%, 73wt%, 74wt%, 75wt%, 76wt%, 77wt%, 78wt%, 79wt%, or 80wt%, the mass fraction of the modified glass powder can be 2.0wt%, 2.5wt%, 3.0wt%, 3.5wt%, 4.0wt%, 4.5wt%, or 5.0wt%, and the mass fraction of the organic carrier can be 15wt%, 16wt%, 17wt%, 18wt%, 19wt%, 20wt%, 21wt%, 22wt%, 23wt%, 24wt%, or 25wt%, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0020] As a preferred embodiment of the present invention, the glass powder, with a weight fraction of 100 wt%, comprises the following components by weight fraction:

[0021] B2O328~32wt%;

[0022] Bi2O330~35wt%;

[0023] ZnO18~22wt%;

[0024] SiO28~12wt%;

[0025] Al2O31~2wt%;

[0026] P2O50.5~1.5wt%;

[0027] TiO21~2wt%;

[0028] ZrO21~2wt%;

[0029] La2O30.1~1wt%;

[0030] MoO30.1~0.5wt%。

[0031] The mass fractions of B2O3 can be 28wt%, 28.5wt%, 29wt%, 29.5wt%, 30wt%, 30.5wt%, 31wt%, 31.5wt%, or 32wt%; the mass fractions of Bi2O3 can be 30wt%, 30.5wt%, 31wt%, 31.5wt%, 32wt%, 32.5wt%, 33wt%, 33.5wt%, 34wt%, 34.5wt%, or 35wt%; and the mass fractions of ZnO can be 18wt%, 18.5wt%, 19wt%, 19.5wt%, 20wt%, or 20.5wt%. The mass fractions of SiO2 can be 8.0wt%, 8.5wt%, 9.0wt%, 9.5wt%, 10.0wt%, 10.5wt%, 11.0wt%, 11.5wt%, or 12.0wt%, and the mass fractions of Al2O3 can be 1.0wt%, 1.1wt%, 1.2wt%, 1.3wt%, 1.4wt%, 1.5wt%, 1.6wt%, 1.7wt%, 1.8wt%, 1.9wt%, or 2.0wt%, and the mass fractions of P2O5 can be 0.5wt%, 0.6wt%, 21wt%, 21.5wt%, or 22wt%. The mass fractions of TiO2 can be 0.7wt%, 0.8wt%, 0.9wt%, 1.0wt%, 1.1wt%, 1.2wt%, 1.3wt%, 1.4wt%, or 1.5wt%, and the mass fractions of ZrO2 can be 1.0wt%, 1.1wt%, 1.2wt%, 1.3wt%, 1.4wt%, 1.5wt%, 1.6wt%, 1.7wt%, 1.8wt%, 1.9wt%, or 2.0wt%, respectively. The mass fraction of La2O3 can be 0.1wt%, 0.2wt%, 0.3wt%, 0.4wt%, 0.5wt%, 0.6wt%, 0.7wt%, 0.8wt%, 0.9wt%, or 1.0wt%, and the mass fraction of MoO3 can be 0.1wt%, 0.15wt%, 0.2wt%, 0.2wt%, 0.25wt%, 0.3wt%, 0.35wt%, 0.4wt%, 0.45wt%, or 0.5wt%, but is not limited to the listed values; other unlisted values ​​within this range also apply.

[0032] As a preferred embodiment of the present invention, the organic carrier, with a mass fraction of 100 wt%, comprises the following components by mass fraction:

[0033] 70-80 wt% terpineol

[0034] Butyl carbitol acetate 5~10 wt%;

[0035] Ethyl cellulose 10~20wt%;

[0036] Thixotropic agent 0.2~0.4wt%.

[0037] The terpineol content can be 70wt%, 71wt%, 72wt%, 73wt%, 74wt%, 75wt%, 76wt%, 77wt%, 78wt%, 79wt%, or 80wt%, the butyl carbitol acetate content can be 5.0wt%, 5.5wt%, 6.0wt%, 6.5wt%, 7.0wt%, 7.5wt%, 8.0wt%, 8.5wt%, 9.0wt%, 9.5wt%, or 10.0wt%, and the ethyl cellulose content can be 10wt%. The mass fraction of the thixotropic agent can be 0.2wt%, 0.22wt%, 0.24wt%, 0.26wt%, 0.28wt%, 0.3wt%, 0.32wt%, 0.34wt%, 0.36wt%, 0.38wt%, or 0.4wt%, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0038] In a second aspect, the present invention provides a method for preparing the copper electronic paste for glass-based printed circuits as described in the first aspect. The preparation method includes:

[0039] (I) B2O3, Bi2O3, ZnO, SiO2, Al2O3, P2O5, TiO2, ZrO2, La2O3 and MoO3 are mixed and melted in proportion to obtain a glass melt. The glass melt is then water-quenched, dried and ground to obtain glass powder. Under stirring and heating conditions, polyethyleneimine and phosphate coupling agent are added to the glass powder, and the modified glass powder is obtained after drying.

[0040] (II) After mixing the dispersant with anhydrous ethanol, spherical copper powder is added and ultrasonically dispersed to obtain a dispersion. Under a nitrogen atmosphere and stirring conditions, an organic titanate is added to the dispersion, followed by the addition of deionized water. The mixture is stirred, heated, and centrifuged. The precipitate is then dried to obtain modified spherical copper powder. Flake copper powder is placed in a fluidized bed and preheated under a nitrogen atmosphere. A silicate solution is sprayed onto the flake copper powder, followed by heat treatment to obtain modified flake copper powder. Under a nitrogen atmosphere, the modified spherical copper powder and the modified flake copper powder are mixed to obtain composite modified copper powder.

[0041] (III) Mix terpineol and butyl carbitol acetate evenly, add ethyl cellulose under stirring and heating conditions, then cool down, add thixotropic agent under stirring conditions, and continue stirring to obtain an organic carrier;

[0042] (IV) The organic carrier is mixed with the composite modified copper powder to obtain an intermediate slurry. The modified glass powder is added to the intermediate slurry in batches to obtain a mixed slurry. The mixed slurry is fed into a roller press for rolling to obtain the glass substrate copper electronic paste.

[0043] Spherical copper powder has a large specific surface area and high surface energy, making it highly susceptible to agglomeration and oxidation. This invention modifies spherical copper powder using an organic titanate. The titanium hydroxyl groups generated after hydrolysis of the organic titanate can form Ti-O-Cu chemical bonds with oxygen in the oxide layer on the surface of the spherical copper powder, thereby grafting an organic monolayer onto the surface of the spherical copper powder. On one hand, the extended organic segments of the organic titanate provide good hydrophobicity to the copper powder, improving its compatibility with the organic carrier. It also prevents nanoparticle agglomeration through steric hindrance, ensuring stable and uniform dispersion in the slurry. On the other hand, the organic monolayer isolates the copper powder from contact with oxygen and moisture, preventing oxidation. The modified spherical copper powder, used as filler particles, exhibits good compatibility with the organic carrier and can be uniformly dispersed. During sintering, the modified spherical copper powder is connected through the molten glass phase, forming nodes and short-range pathways in the conductive network.

[0044] Flake copper powder has a large aspect ratio, making it prone to breakage under shear forces during subsequent rolling, and its flake edges are more susceptible to oxidation. This invention modifies it by spraying a silicate solution onto the powder in a fluidized bed. During heat treatment, the silicate undergoes dehydration and gelation, ultimately forming a uniform and dense silicate glassy coating layer on the surface of the flake copper powder. This coating layer has high mechanical strength and good thermal stability, effectively resisting shear forces during subsequent rolling and preventing breakage. Simultaneously, the continuous and dense glassy coating layer effectively prevents oxygen and moisture from directly contacting the flake copper powder, preventing oxidation. The modified flake copper powder acts as an interlayer, its hard inorganic coating layer maintaining its flake shape before sintering. During sintering, the coating layer reacts and melts with the glass powder, forming a high-strength transition interface between the flake copper powder and the glassy binder phase. The overlapping of the flake copper powder forms surface contact, constituting the long-range backbone and conductive bridges of the conductive network.

[0045] This invention combines modified spherical copper powder and modified flake copper powder in a specific ratio to form a three-dimensional interpenetrating network structure of sphere-flake interlocking after sintering. In the conductive film layer, the modified spherical copper powder fills the gaps between the modified flake copper powder, thereby improving the packing density and compactness of the conductive film layer.

[0046] The glass powder in this invention is composed of B2O3, Bi2O3, ZnO, SiO2, Al2O3, P2O5, TiO2, ZrO2, La2O3, and MoO3, achieving low-temperature sintering, good wettability, a suitable coefficient of thermal expansion, and strong interfacial bonding. B2O3 and Bi2O3 are primarily used to achieve low-temperature sintering; B2O3 significantly reduces the melting point and viscosity of the glass. Bi2O3 not only lowers the melting point itself but also forms a eutectic with B2O3, enabling low-temperature sintering. ZnO, SiO2, and Al2O3 are mainly used to adjust the coefficient of thermal expansion of the conductive film. The addition of ZnO effectively regulates the coefficient of thermal expansion of the glass, placing it between that of copper and the glass substrate, reducing internal stress and film cracking caused by mismatched coefficients of thermal expansion. Simultaneously, ZnO improves the chemical stability of the glass and its wettability to copper. SiO2 and Al2O3 enhance the glass network structure, improving the mechanical strength and weather resistance of the conductive film. P2O5, TiO2, ZrO2, La2O3, and MoO3 are primarily used to enhance the interfacial bonding between the conductive film and the glass substrate. P2O5 further lowers the softening point and improves adhesion to the metal. TiO2 and ZrO2 are high-strength, chemically resistant components that improve the mechanical strength of the glass phase and its reactivity with the glass substrate, thus enhancing adhesion between them. Trace amounts of La2O3 can increase the high-temperature viscosity of the glass, preventing excessive flow. MoO3 acts as a flux and promotes wetting of the copper surface. Through the synergistic effect of these components, the glass powder can melt at a lower temperature, effectively wetting both the copper powder and the glass substrate, and the resulting conductive film's coefficient of thermal expansion matches that of the glass substrate.

[0047] This invention employs a composite modification of glass powder using polyethyleneimine and a phosphate ester coupling agent. Polyethyleneimine is a high-molecular polymer with numerous primary and secondary amine groups. These strongly polar groups can form hydrogen bonds and electrostatic adsorption with metal ions and hydroxyl groups on the glass powder surface, thus firmly adhering to the glass powder surface. This improves the physicochemical properties of the glass powder surface, enhances the interfacial compatibility between the glass powder and the organic carrier, and effectively prevents the glass powder from agglomerating or settling due to polarity mismatch during slurry storage and processing, ensuring the uniformity of the slurry. The phosphate ester coupling agent has phosphate groups and long organic chains. After treatment with polyethyleneimine, the addition of the phosphate ester coupling agent allows the phosphate groups to interact with the Bi atoms on the glass powder surface. 3+ Zn 2+ Ti 4+ When metal ions form strong chemical bonds, the long organic chains become physically entangled with the molecular chains of polyethyleneimine, thus forming a composite organic layer on the surface of the glass powder composed of polyethyleneimine and phosphate coupling agent.

[0048] The composite organic layer serves two purposes: firstly, it ensures stable dispersion of glass powder in the slurry; secondly, its thermal decomposition during sintering promotes the wetting and spreading of copper powder by the molten glass. During sintering, the molten glass can more evenly coat and bond each copper powder particle. After cooling, the glass phase fills all the gaps between the copper powder particles, thus forming a dense copper-glass composite. This achieves high adhesion, high density, and excellent conductivity of the film.

[0049] In the preparation of the organic carrier, terpineol and butyl carbitol acetate, two solvents, are first mixed. The combination of these two solvents exhibits excellent solubility and dispersion of solid particles. Subsequently, ethyl cellulose is added under heating and stirring conditions. Heating reduces the solution viscosity, promoting the full extension and dissolution of the ethyl cellulose polymer chains, thus forming a homogeneous and stable polymer solution. Finally, cooling is applied and a thixotropic agent is added. The addition of the thixotropic agent gives the slurry a high viscosity at rest, preventing solid particle sedimentation. During printing and coating, the viscosity rapidly decreases under shear force, resulting in good printing leveling properties.

[0050] Finally, this invention mixes modified glass powder, composite modified copper powder, and an organic carrier, and achieves uniform dispersion and densification of solid particles through rolling. During mixing, the organic carrier and composite modified copper powder are first mixed to form an intermediate slurry. The organic carrier wets and coats the copper powder particles. Then, modified glass powder is added in batches. Because the density, particle size, and surface properties of the modified glass powder differ from those of the composite modified copper powder, adding a large amount at once can easily lead to dispersion difficulties and localized agglomeration. Adding it in batches ensures that the modified glass powder is fully wetted and dispersed. Finally, multiple rolling passes are performed. The enormous shear force promotes the wetting of the particle surface by the organic carrier, removes interfacial bubbles, and completely breaks up particle agglomeration, ensuring that the copper powder and glass powder are uniformly and fully coated by the organic carrier. Furthermore, the gradual reduction of the roller gap causes the flake-like copper powder to orient itself, resulting in a denser and more uniform slurry.

[0051] As a preferred technical solution of the present invention, in step (I), the melting temperature is 1000~1100℃, for example, it can be 1000℃, 1010℃, 1020℃, 1030℃, 1040℃, 1050℃, 1060℃, 1070℃, 1080℃, 1090℃ or 1100℃, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0052] In some optional instances, the melting time is 40 to 60 minutes, for example, 40 minutes, 42 minutes, 44 minutes, 46 minutes, 48 ​​minutes, 50 minutes, 52 minutes, 54 minutes, 56 minutes, 58 minutes or 60 minutes, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0053] In some alternative instances, the drying temperature is 120~150°C, for example, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C or 150°C, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0054] In some optional instances, the particle size D50 of the glass powder is 1 to 2 μm, for example, it can be 1.0 μm, 1.1 μm, 1.2 μm, 1.3 μm, 1.4 μm, 1.5 μm, 1.6 μm, 1.7 μm, 1.8 μm, 1.9 μm or 2.0 μm, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0055] In some optional examples, polyethyleneimine is added to the glass powder under stirring and heating conditions of 50-70°C, for example, at 50°C, 52°C, 54°C, 56°C, 58°C, 60°C, 62°C, 64°C, 66°C, 68°C, or 70°C. After mixing for 15-25 minutes, a phosphate coupling agent is added, for example, for 15 minutes, 16 minutes, 17 minutes, 18 minutes, 19 minutes, 20 minutes, 21 minutes, 22 minutes, 23 minutes, 24 minutes, or 25 minutes. Mixing continues for 20-30 minutes, for example, for 20 minutes, 21 minutes, 22 minutes, 23 minutes, 24 minutes, 25 minutes, 26 minutes, 27 minutes, 28 minutes, 29 minutes, or 30 minutes, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0056] In some optional examples, the amount of polyethyleneimine added is 0.2 to 0.4 wt% of the mass of the glass powder, for example, 0.2 wt%, 0.22 wt%, 0.24 wt%, 0.26 wt%, 0.28 wt%, 0.3 wt%, 0.32 wt%, 0.34 wt%, 0.36 wt%, 0.38 wt%, or 0.4 wt%, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0057] This invention specifically limits the amount of polyethyleneimine added to 0.2~0.4 wt% of the glass powder mass. If the amount of polyethyleneimine added is too low, a complete coating layer cannot be formed on the surface of the glass powder, resulting in poor compatibility of the glass powder in the organic carrier, easy particle agglomeration, and damage to the stability of the slurry. If the amount of polyethyleneimine added is too high, an excessively thick coating layer will be formed on the surface of the glass powder, which will not only hinder the chemical bonding between the phosphate coupling agent and the surface of the glass powder, but also generate a large amount of gas due to the decomposition of excessive organic matter during subsequent sintering, forming pores or cracks in the conductive film layer and affecting its structural density.

[0058] In some optional examples, the amount of the phosphate coupling agent added is 0.3 to 0.5 wt% of the mass of the glass powder, for example, it can be 0.3 wt%, 0.32 wt%, 0.34 wt%, 0.36 wt%, 0.38 wt%, 0.4 wt%, 0.42 wt%, 0.44 wt%, 0.46 wt%, 0.48 wt%, or 0.5 wt%, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0059] This invention specifically limits the amount of phosphate coupling agent added to 0.3~0.5wt% of the glass powder mass. If the amount of phosphate coupling agent added is too low, a complete coating layer cannot be formed, resulting in poor compatibility between the glass powder and the organic carrier, easy particle aggregation, and insufficient wetting and spreading of copper powder by the molten glass during sintering, affecting the density and adhesion of the film layer. If the amount of phosphate coupling agent added is too high, the excess phosphate molecules cannot all combine with the surface of the glass powder, and the excess phosphate will exist in a free state in the slurry, affecting the rheological properties of the slurry. It will also generate gas due to the decomposition of organic matter during sintering, forming pores or cracks in the conductive film layer, affecting its structural density.

[0060] It should be noted that the present invention does not impose specific requirements or special limitations on the type of phosphate coupling agent. For example, it may be isopropyl tris(dioctylphosphoyloxy)titanate.

[0061] In some alternative instances, the drying temperature is 120~150°C, for example, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C or 150°C, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0062] As a preferred technical solution of the present invention, in step (II), the dispersant includes any one or a combination of at least two of oleic acid, linoleic acid, linolenic acid or lecithin.

[0063] In some alternative instances, the mass ratio of the dispersant to the anhydrous ethanol is 1:(15~25), for example, it can be 1:15, 1:16, 1:17, 1:18, 1:19, 1:20, 1:21, 1:22, 1:23, 1:24 or 1:25, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0064] In some optional instances, the particle size D50 of the spherical copper powder is 100~200nm, for example, it can be 100nm, 110nm, 120nm, 130nm, 140nm, 150nm, 160nm, 170nm, 180nm, 190nm or 200nm, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0065] In some optional instances, the mass ratio of the spherical copper powder to the dispersant is (8~12):1, for example, it can be 8.0:1, 8.5:1, 9.0:1, 9.5:1, 10.0:1, 10.5:1, 11.0:1, 11.5:1 or 12.0:1, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0066] In some optional instances, the ultrasonic power of the ultrasonic dispersion is 300 to 500 W, for example, 300 W, 320 W, 340 W, 360 W, 380 W, 400 W, 420 W, 440 W, 460 W, 480 W or 500 W, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0067] In some optional instances, the ultrasonic dispersion time is 20 to 30 minutes, for example, 20 minutes, 21 minutes, 22 minutes, 23 minutes, 24 minutes, 25 minutes, 26 minutes, 27 minutes, 28 minutes, 29 minutes or 30 minutes, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0068] In some optional examples, the amount of the organic titanate added is 0.5 to 1 wt% of the mass of the spherical copper powder, for example, it can be 0.5 wt%, 0.55 wt%, 0.6 wt%, 0.65 wt%, 0.7 wt%, 0.75 wt%, 0.8 wt%, 0.85 wt%, 0.9 wt%, 0.95 wt%, or 1.0 wt%, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0069] This invention specifically limits the addition amount of organic titanate to 0.5~1wt% of the mass of spherical copper powder. If the addition amount of organic titanate is too low, it is insufficient to cover the surface of the copper powder, resulting in exposed copper powder surface, which is easily oxidized, severely affecting the conductivity of the film. In addition, due to insufficient organic titanate, the surface modification of copper powder is incomplete, the dispersion of copper powder in the organic carrier becomes poor, and agglomeration easily occurs, affecting the uniformity of the slurry and the density of the film. Conversely, if the addition amount of organic titanate is too high, the excess organic titanate cannot be completely adsorbed on the surface of copper powder, and the excess organic titanate exists in a free state in the slurry. During sintering, the concentrated decomposition of too much organic matter generates a large amount of gas, forming pores or cracks in the film, affecting its structural density. Furthermore, excessive organic titanate will form an excessively thick coating layer on the surface of copper powder, which hinders the effective electrical connection between copper powder particles during sintering, affecting the conductivity of the film.

[0070] In some optional examples, the organic titanate is tetraisopropyl titanate and / or tetrabutyl titanate.

[0071] In some optional instances, the amount of deionized water added is 1 to 2 wt% of the mass of the organic titanate, for example, it may be 1.0 wt%, 1.1 wt%, 1.2 wt%, 1.3 wt%, 1.4 wt%, 1.5 wt%, 1.6 wt%, 1.7 wt%, 1.8 wt%, 1.9 wt%, or 2.0 wt%, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0072] In some optional instances, the mixing and heating temperature is 40~50°C, for example, it can be 40°C, 41°C, 42°C, 43°C, 44°C, 45°C, 46°C, 47°C, 48°C, 49°C or 50°C, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0073] In some optional instances, the mixing and heating time is 1 to 2 hours, for example, 1.0 hours, 1.1 hours, 1.2 hours, 1.3 hours, 1.4 hours, 1.5 hours, 1.6 hours, 1.7 hours, 1.8 hours, 1.9 hours, or 2.0 hours, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0074] In some optional instances, the centrifugal separation speed is 10,000 to 12,000 rpm, for example, it can be 10,000 rpm, 10,200 rpm, 10,400 rpm, 10,600 rpm, 10,800 rpm, 11,000 rpm, 11,200 rpm, 11,400 rpm, 11,600 rpm, 11,800 rpm or 12,000 rpm, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0075] In some optional instances, the centrifugation time is 10 to 20 minutes, for example, 10 minutes, 11 minutes, 12 minutes, 13 minutes, 14 minutes, 15 minutes, 16 minutes, 17 minutes, 18 minutes, 19 minutes or 20 minutes, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0076] In some optional instances, the drying temperature is 50-60°C, the drying is to a constant weight, and the drying atmosphere is nitrogen, for example, 50°C, 51°C, 52°C, 53°C, 54°C, 55°C, 56°C, 57°C, 58°C, 59°C, or 60°C, but not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0077] As a preferred technical solution of the present invention, in step (II), the diameter D50 of the flake copper powder is 0.8~1.2μm, for example, it can be 0.8μm, 0.85μm, 0.9μm, 0.95μm, 1.0μm, 1.05μm, 1.1μm, 1.15μm or 1.2μm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0078] In some optional instances, the aspect ratio of the flake copper powder is (8~12):1, for example, it can be 8.0:1, 8.5:1, 9.0:1, 9.5:1, 10.0:1, 10.5:1, 11.0:1, 11.5:1 or 12.0:1, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0079] In some alternative instances, the flake copper powder is placed in a fluidized bed and preheated to 80-100°C in a nitrogen atmosphere, for example, 80°C, 82°C, 84°C, 86°C, 88°C, 90°C, 92°C, 94°C, 96°C, 98°C, or 100°C, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0080] In some optional instances, the mass fraction of the silicate solution is 3 to 5 wt%, for example, it may be 3.0 wt%, 3.2 wt%, 3.4 wt%, 3.6 wt%, 3.8 wt%, 4.0 wt%, 4.2 wt%, 4.4 wt%, 4.6 wt%, 4.8 wt%, or 5.0 wt%, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0081] It should be noted that the present invention does not impose specific requirements or special limitations on the type of silicate; for example, it may be sodium silicate.

[0082] In some alternative instances, the mass ratio of the silicate solution to the flake copper powder is 1:(60~80), for example, it can be 1:60, 1:62, 1:64, 1:66, 1:68, 1:70, 1:72, 1:74, 1:76, 1:78 or 1:80, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0083] This invention specifically limits the mass ratio of silicate solution to flake copper powder to 1:(60~80). If the amount of silicate solution is too high, an excessively thick coating layer will form on the surface of the flake copper powder. During subsequent sintering, this excessively thick coating layer will hinder the effective electrical connection between copper powder particles, affecting the conductivity of the film. If the amount of silicate solution is too low, a continuous and complete coating layer cannot be formed on the surface of the flake copper powder. The exposed surface of the flake copper powder is easily oxidized, leading to a decrease in the conductivity of the film. At the same time, an incomplete coating layer cannot provide effective physical protection, and the flake copper powder is easily damaged during rolling.

[0084] In some optional instances, the heat treatment is performed at 120~150°C for 10~20 min, wherein the heat treatment temperature can be 120°C, 125°C, 130°C, 135°C, 140°C, 145°C or 150°C, and the heat treatment time can be 10 min, 11 min, 12 min, 13 min, 14 min, 15 min, 16 min, 17 min, 18 min, 19 min or 20 min, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0085] In some optional instances, the mass ratio of the modified spherical copper powder to the modified flake copper powder is (4~5):1, for example, it can be 4.0:1, 4.1:1, 4.2:1, 4.3:1, 4.4:1, 4.5:1, 4.6:1, 4.7:1, 4.8:1, 4.9:1 or 5.0:1, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0086] This invention specifically limits the mass ratio of modified spherical copper powder to modified flake copper powder to (4~5):1. If the proportion of modified spherical copper powder is too high and the proportion of flake copper powder is insufficient, the overlapping effect of the flake copper powder cannot be effectively utilized, the long-range connectivity of the conductive network in the film layer deteriorates, electron transmission needs to pass through more sphere-to-sphere contact points, the contact resistance increases, and the conductivity decreases. If the proportion of modified spherical copper powder is too low, the gaps between the modified flake copper powder cannot be fully filled, the compactness of the film layer decreases, and at the same time, too much flake copper powder will overlap, affecting the effective electrical connection between the flake copper powders, resulting in a decrease in the conductivity of the film layer.

[0087] As a preferred technical solution of the present invention, in step (III), the terpineol and butyl carbitol acetate are mixed evenly and then heated to 85~95°C, for example, 85°C, 86°C, 87°C, 88°C, 90°C, 91°C, 92°C, 93°C, 94°C or 95°C. Ethyl cellulose is added under stirring and heating conditions, and the mixture is stirred at a constant temperature for 2~4 hours, for example, 2.0h, 2.2h, 2.4h, 2.6h, 2.8h, 3.0h, 3.2h, 3.4h, 3.6h, 3.8h or 4.0h, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0088] In some alternative examples, the thixotropic agent is added after cooling to 40-50°C, for example, at 40°C, 41°C, 42°C, 43°C, 44°C, 45°C, 46°C, 47°C, 48°C, 49°C, or 50°C, and then stirred at a constant temperature for 1-2 hours, for example, 1.0h, 1.1h, 1.2h, 1.3h, 1.4h, 1.5h, 1.6h, 1.7h, 1.8h, 1.9h, or 2.0h, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0089] In some optional instances, the thixotropic agent is a polyamide wax-based thixotropic agent.

[0090] As a preferred technical solution of the present invention, in step (IV), the organic carrier and the composite modified copper powder are mixed in a planetary stirred tank.

[0091] In some optional instances, the planetary agitator has a revolution speed of 15 to 25 rpm, for example, 15 rpm, 16 rpm, 17 rpm, 18 rpm, 19 rpm, 20 rpm, 21 rpm, 22 rpm, 23 rpm, 24 rpm or 25 rpm, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0092] In some optional instances, the planetary agitator rotates at a speed of 30 to 50 rpm, for example, 30 rpm, 32 rpm, 34 rpm, 36 rpm, 38 rpm, 40 rpm, 42 rpm, 44 rpm, 46 rpm, 48 rpm or 50 rpm, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0093] In some optional instances, the mixing time of the organic carrier and the composite modified copper powder in the planetary stirred tank is 40 to 60 minutes, for example, 40 minutes, 42 minutes, 44 minutes, 46 minutes, 48 ​​minutes, 50 minutes, 52 minutes, 54 minutes, 56 minutes, 58 minutes or 60 minutes, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0094] In some optional instances, the modified glass powder is added to the planetary stirred tank in 2 to 3 equal portions, and mixed for 10 to 20 minutes after each addition, for example, 10 minutes, 11 minutes, 12 minutes, 13 minutes, 14 minutes, 15 minutes, 16 minutes, 17 minutes, 18 minutes, 19 minutes or 20 minutes, but not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0095] In some alternative instances, the mixed slurry is rolled in a three-roll mill, which includes a feed roll, an intermediate roll, and an outlet roll, wherein the gap between the feed roll and the intermediate roll is greater than the gap between the outlet roll and the intermediate roll.

[0096] In some optional instances, the gap between the feed rollers is 20 to 30 μm, for example, it can be 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm, 26 μm, 27 μm, 28 μm, 29 μm or 30 μm, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0097] In some optional instances, the gap between the intermediate rollers is 10 to 20 μm, for example, it can be 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm or 20 μm, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0098] In some optional instances, the gap between the discharge rollers is 5 to 10 μm, for example, it can be 5.0 μm, 5.5 μm, 6.0 μm, 6.5 μm, 7.0 μm, 7.5 μm, 8.0 μm, 8.5 μm, 9.0 μm, 9.5 μm or 10.0 μm, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0099] In some alternative instances, the mixed slurry is rolled 8 to 12 times in the three-roll mill, for example, 8, 9, 10, 11 or 12 times, but not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0100] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0101] The copper electronic paste provided by this invention consists of a conductive phase, a binder phase, and an organic matrix. The conductive phase comprises spherical copper powder modified with organic titanate and flake copper powder modified with silicate. The binder phase is glass powder modified with polyethyleneimine and a phosphate coupling agent. The organic carrier consists of terpineol, butyl carbitol acetate, ethyl cellulose, and a thixotropic agent, ultimately forming a high-performance copper electronic paste for glass-based printed circuits. The composite modified copper powder effectively inhibits the oxidation and agglomeration of copper powder, ensuring the formation of a dense, low-resistance conductive network after sintering. The modified glass powder enhances the interfacial bonding force with the composite modified copper powder and the glass substrate and matches the coefficient of thermal expansion. The organic carrier provides excellent printability and paste stability. The copper electronic paste provided by this invention solves the technical problems of poor film conductivity, insufficient adhesion, and easy cracking and peeling caused by the easy oxidation of copper, poor interfacial compatibility between glass powder and copper powder, and differences in the coefficient of thermal expansion of traditional copper pastes. Attached Figure Description

[0102] Figure 1 The infrared spectrum of the modified glass powder prepared in Example 1 of this invention;

[0103] Figure 2 This is a scanning electron microscope image of the composite modified copper powder prepared in Example 1 of the present invention. Detailed Implementation

[0104] The technical solutions of the present invention will be described in detail below with reference to specific embodiments and accompanying drawings. The embodiments described herein are specific implementations of the present invention, used to illustrate the concept of the present invention; these descriptions are explanatory and exemplary, and should not be construed as limiting the implementation methods or the scope of protection of the present invention. In addition to the embodiments described herein, those skilled in the art can employ other obvious technical solutions based on the content disclosed in the claims and specification of this application. These technical solutions include those that make any obvious substitutions and modifications to the embodiments described herein.

[0105] Example 1

[0106] This embodiment provides a method for preparing copper electronic paste for glass-based printed circuits, the preparation method specifically including the following steps:

[0107] (1) B2O3, Bi2O3, ZnO, SiO2, Al2O3, P2O5, TiO2, ZrO2, La2O3 and MoO3 were mixed in proportion and heated to melt at 1000℃ for 60 min to obtain glass melt. The glass melt was quenched with water and then dried at 120℃ to constant weight. Finally, after grinding and sieving, glass powder with a particle size D50 of 1 μm was obtained.

[0108] Based on a weight fraction of 100 wt% for the glass powder, it comprises the following components by weight fraction:

[0109] B2O3 28wt%

[0110] Bi2O3 35wt%

[0111] ZnO 20wt%

[0112] SiO2 8wt%

[0113] Al2O32wt%

[0114] P2O5 1.5wt%

[0115] TiO2 2wt%

[0116] ZrO2 2wt%

[0117] La2O 31wt%

[0118] MoO3 0.5 wt%;

[0119] Under stirring and heating conditions at 50°C, polyethyleneimine was added to the glass powder at an amount of 0.2 wt% of the glass powder mass. After mixing for 25 min, isopropyl tris(dioctylphosphoyloxy)titanate was added at an amount of 0.3 wt% of the glass powder mass. Mixing was continued for 30 min, and then the mixture was dried at 120°C to constant weight to obtain modified glass powder.

[0120] (2) Oleic acid and anhydrous ethanol were mixed evenly at a mass ratio of 1:15. Spherical copper powder with a particle size D50 of 100 nm was added. The mass ratio of spherical copper powder to oleic acid was 8:1. The mixture was then ultrasonically dispersed at an ultrasonic power of 300 W for 30 min to obtain a dispersion. Tetraisopropyl titanate was added to the dispersion under a nitrogen atmosphere and stirring conditions. The amount of tetraisopropyl titanate added was 0.5 wt% of the mass of the spherical copper powder. After mixing evenly, deionized water was added dropwise. The amount of deionized water added was 1 wt% of the mass of tetraisopropyl titanate. The mixture was then stirred and heated at 40 °C for 2 h. Finally, the mixture was centrifuged at a speed of 10000 rpm for 20 min to collect the precipitate. The precipitate was dried to constant weight under a nitrogen atmosphere and at 50 °C to obtain modified spherical copper powder.

[0121] Flake copper powder was placed in a fluidized bed. The diameter (D50) of the flake copper powder was 0.8 μm and the diameter-to-thickness ratio was 8:1. The flake copper powder was preheated to 80°C under a nitrogen atmosphere. A sodium silicate solution with a mass fraction of 3 wt% was sprayed onto the flake copper powder. The mass ratio of sodium silicate solution to flake copper powder was 1:60. After the sodium silicate solution was sprayed, the sprayed flake copper powder was heat-treated at 120°C under a nitrogen atmosphere for 20 min to obtain modified flake copper powder.

[0122] Under a nitrogen atmosphere, modified spherical copper powder and modified flake copper powder were mixed evenly at a mass ratio of 4:1 to obtain composite modified copper powder.

[0123] (3) After mixing terpineol and butyl carbitol acetate evenly, heat to 85°C. Add ethyl cellulose under stirring and heating at 85°C, and stir at constant temperature for 4 hours. After the mixed solution cools down to 40°C, add polyamide wax thixotropic agent (hexamethylene bis(1-dodecyl)-hydroxystearamide), and continue stirring at constant temperature for 2 hours to obtain an organic carrier.

[0124] Based on an organic carrier mass fraction of 100 wt%, it comprises the following components by mass fraction:

[0125] 70 wt% terpineol

[0126] Butyl carbitol acetate 9.8 wt%;

[0127] 20wt% ethyl cellulose

[0128] Hexamethylene di-dodecyl stearamide 0.2 wt%;

[0129] (4) The organic carrier obtained in step (3) and the composite modified copper powder obtained in step (2) are added into a planetary stirring vessel. The planetary stirring vessel has a revolution speed of 15 rpm and a rotation speed of 30 rpm. The mixture is stirred for 60 min. Then, the modified glass powder obtained in step (1) is added into the planetary stirring vessel in two equal batches. After each addition, the mixture is stirred for 20 min to obtain a mixed slurry.

[0130] The mixed slurry is fed into a three-roll mill for rolling. Along the direction of movement of the mixed slurry, the three-roll mill includes a feed roll, an intermediate roll, and a discharge roll. The gap between the feed roll and the intermediate roll is 20 μm, the gap between the intermediate roll and the gap between the discharge roll and the discharge roll is 5 μm. After rolling 12 times, the copper electronic paste for glass substrate is obtained.

[0131] Based on a weight fraction of 100 wt% for copper electronic paste used in glass-based printed circuits, it comprises the following components by mass fraction:

[0132] 70wt% of composite modified copper powder;

[0133] Modified glass powder 5wt%;

[0134] Organic carrier 25wt%.

[0135] Figure 1 The infrared spectrum of the modified glass powder prepared in this embodiment is shown at 3400 cm⁻¹. -1 The broad and strong absorption peak at 2900 cm⁻¹ is attributed to the stretching vibrations of the OH and NH bonds. The OH groups originate from trace amounts of moisture, Si-OH, and B-OH groups adsorbed on the glass powder surface, while the NH groups originate from the primary and secondary amine groups in the polyethyleneimine molecule. -1 The absorption peak at [value] is attributed to the CH stretching vibrations of the alkyl chains in polyethyleneimine and isopropyltris(dioctylphosphoyloxy)titanate molecules. (1000–1100 cm⁻¹) -1 The strong and broad absorption bands within this range are attributed to the stretching vibrations of Si-O-Si. (900~1000 cm⁻¹) -1 The absorption peaks within this range are attributed to the stretching vibrations of the P=O bond, originating from isopropyl tris(dioctylphosphoyloxy)titanate. (500–800 cm⁻¹) -1 The absorption peaks within the range are attributed to the vibrations of the Ti-O bonds in the hydrolysis products of isopropyl tris(dioctylphosphoyloxy)titanate and the metal-oxygen bonds such as Zn-O in the glass powder. This infrared spectrum indicates that the amino groups of polyethyleneimine and the phosphate groups of the phosphate coupling agent were successfully grafted onto the surface of the glass powder.

[0136] Figure 2The image shows a scanning electron microscope (SEM) image of the composite modified copper powder prepared in this embodiment. As can be seen from the image, the modified flake copper powder is uniformly dispersed, and the modified spherical copper powder is dispersed in the gaps between the modified flake copper powder. An extremely thin coating layer can be observed on the surface of the particles. This coating layer is formed by the hydrolysis of tetraisopropyl titanate on the surface of the spherical copper powder and by the silicate coating layer formed by sodium silicate on the surface of the flake copper powder.

[0137] Example 2

[0138] This embodiment provides a method for preparing copper electronic paste for glass-based printed circuits, the preparation method specifically including the following steps:

[0139] (1) B2O3, Bi2O3, ZnO, SiO2, Al2O3, P2O5, TiO2, ZrO2, La2O3 and MoO3 were mixed in proportion and heated to melt at 1020℃ for 55 min to obtain glass melt. The glass melt was quenched with water and then dried at 130℃ to constant weight. Finally, after grinding and sieving, glass powder with a particle size D50 of 1.2 μm was obtained.

[0140] Based on a weight fraction of 100 wt% for the glass powder, it comprises the following components by weight fraction:

[0141] B2O3 29wt%

[0142] Bi2O3 34wt%

[0143] ZnO 18wt%

[0144] SiO2 11wt%

[0145] Al2O3 1.8 wt%

[0146] P2O5 1.2wt%;

[0147] TiO2 1.8wt%

[0148] ZrO2 1.8wt%

[0149] La2O 31wt%

[0150] MoO 30.4wt%

[0151] Under stirring and heating conditions at 55°C, polyethyleneimine was added to the glass powder at an amount of 0.25 wt% of the glass powder mass. After mixing for 22 min, isopropyl tris(dioctylphosphoyloxy)titanate was added at an amount of 0.35 wt% of the glass powder mass. Mixing was continued for 28 min, and then the mixture was dried at 130°C to constant weight to obtain modified glass powder.

[0152] (2) Oleic acid and anhydrous ethanol were mixed evenly at a mass ratio of 1:18. Spherical copper powder with a particle size D50 of 120 nm was added. The mass ratio of spherical copper powder to oleic acid was 9:1. The mixture was then ultrasonically dispersed at an ultrasonic power of 350 W for 28 min to obtain a dispersion. Tetraisopropyl titanate was added to the dispersion under a nitrogen atmosphere and stirring conditions. The amount of tetraisopropyl titanate added was 0.6 wt% of the mass of the spherical copper powder. After mixing evenly, deionized water was added dropwise. The amount of deionized water added was 1.2 wt% of the mass of tetraisopropyl titanate. The mixture was then stirred and heated at 42 °C for 1.8 h. Finally, the mixture was centrifuged at a speed of 10500 rpm for 18 min to collect the precipitate. The precipitate was dried to constant weight under a nitrogen atmosphere and at 52 °C to obtain modified spherical copper powder.

[0153] Flake copper powder with a diameter D50 of 0.9 μm and a diameter-to-thickness ratio of 9:1 was placed in a fluidized bed. The flake copper powder was preheated to 85°C under a nitrogen atmosphere. A sodium silicate solution with a mass fraction of 3.5 wt% was sprayed onto the flake copper powder. The mass ratio of sodium silicate solution to flake copper powder was 1:65. After the sodium silicate solution was sprayed, the sprayed flake copper powder was heat-treated at 130°C for 18 min under a nitrogen atmosphere to obtain modified flake copper powder.

[0154] Under a nitrogen atmosphere, modified spherical copper powder and modified flake copper powder were mixed evenly at a mass ratio of 4.2:1 to obtain composite modified copper powder.

[0155] (3) After mixing terpineol and butyl carbitol acetate evenly, heat to 88°C. Add ethyl cellulose under stirring and heating at 88°C, and stir at constant temperature for 3.5 h. After the mixed solution cools down to 42°C, add polyamide wax thixotropic agent (hexamethylene bis(1-dodecyl)-hydroxystearamide), and continue stirring at constant temperature for 1.8 h to obtain an organic carrier.

[0156] Based on an organic carrier mass fraction of 100 wt%, it comprises the following components by mass fraction:

[0157] 72 wt% terpineol;

[0158] Butyl carbitol acetate 10 wt%

[0159] Ethyl cellulose 17.7 wt%;

[0160] Hexamethylene di-dodecyl stearamide 0.3 wt%;

[0161] (4) The organic carrier obtained in step (3) and the composite modified copper powder obtained in step (2) are added into a planetary mixing vessel. The planetary mixing vessel has a revolution speed of 18 rpm and a rotation speed of 35 rpm. The mixture is stirred for 55 min. Then, the modified glass powder obtained in step (1) is added into the planetary mixing vessel in two equal batches. After each addition, the mixture is stirred for 18 min to obtain a mixed slurry.

[0162] The mixed slurry is fed into a three-roll mill for rolling. Along the moving direction of the mixed slurry, the three-roll mill includes a feed roll, an intermediate roll, and a discharge roll. The gap between the feed roll and the intermediate roll is 22 μm, the gap between the intermediate roll and the gap between the discharge roll and the discharge roll is 6 μm. After rolling 11 times, the copper electronic paste for glass substrate is obtained.

[0163] Based on a weight fraction of 100 wt% for copper electronic paste used in glass-based printed circuits, it comprises the following components by mass fraction:

[0164] 72wt% of composite modified copper powder;

[0165] 4wt% modified glass powder;

[0166] Organic carrier 24wt%.

[0167] Example 3

[0168] This embodiment provides a method for preparing copper electronic paste for glass-based printed circuits, the preparation method specifically including the following steps:

[0169] (1) B2O3, Bi2O3, ZnO, SiO2, Al2O3, P2O5, TiO2, ZrO2, La2O3 and MoO3 were mixed in proportion and heated to melt at 1050℃ for 50 min to obtain glass melt. The glass melt was quenched with water and then dried at 130℃ to constant weight. Finally, after grinding and sieving, glass powder with a particle size D50 of 1.5 μm was obtained.

[0170] Based on a weight fraction of 100 wt% for the glass powder, it comprises the following components by weight fraction:

[0171] B2O3 29wt%

[0172] Bi2O3 33wt%

[0173] ZnO 21wt%

[0174] SiO2 10wt%

[0175] Al2O3 1.5 wt%

[0176] P2O5 1wt%

[0177] TiO2 1.5wt%

[0178] ZrO2 1.5wt%

[0179] La2O 31wt%

[0180] MoO3 0.5 wt%;

[0181] Under stirring and heating conditions at 60°C, polyethyleneimine was added to glass powder at an amount of 0.3 wt% of the glass powder mass. After mixing for 20 min, isopropyl tris(dioctylphosphoyloxy)titanate was added at an amount of 0.4 wt% of the glass powder mass. Mixing was continued for 25 min, and then dried at 130°C to constant weight to obtain modified glass powder.

[0182] (2) Linoleic acid and anhydrous ethanol were mixed evenly at a mass ratio of 1:20. Spherical copper powder with a particle size D50 of 150 nm was added. The mass ratio of spherical copper powder to linoleic acid was 10:1. The mixture was then ultrasonically dispersed at an ultrasonic power of 400 W for 25 min to obtain a dispersion. Tetrabutyl titanate was added to the dispersion under a nitrogen atmosphere and stirring conditions. The amount of tetrabutyl titanate added was 0.7 wt% of the mass of the spherical copper powder. After mixing evenly, deionized water was added dropwise. The amount of deionized water added was 1.5 wt% of the mass of tetrabutyl titanate. The mixture was then stirred and heated at 45 °C for 1.5 h. Finally, the mixture was centrifuged at 11000 rpm for 15 min to collect the precipitate. The precipitate was dried to constant weight under a nitrogen atmosphere and at 55 °C to obtain modified spherical copper powder.

[0183] Flake copper powder was placed in a fluidized bed. The diameter (D50) of the flake copper powder was 1 μm and the diameter-to-thickness ratio was 10:1. The flake copper powder was preheated to 90°C under a nitrogen atmosphere. A sodium silicate solution with a mass fraction of 4 wt% was sprayed onto the flake copper powder. The mass ratio of sodium silicate solution to flake copper powder was 1:70. After the sodium silicate solution was sprayed, the sprayed flake copper powder was heat-treated at 130°C under a nitrogen atmosphere for 15 min to obtain modified flake copper powder.

[0184] Under a nitrogen atmosphere, modified spherical copper powder and modified flake copper powder were mixed evenly at a mass ratio of 4.5:1 to obtain composite modified copper powder.

[0185] (3) After mixing terpineol and butyl carbitol acetate evenly, heat to 90°C. Add ethyl cellulose under stirring and heating at 90°C, and stir at constant temperature for 3 hours. After the mixed solution cools down to 45°C, add polyamide wax thixotropic agent (hexamethylene bis(1-dodecyl)-hydroxystearamide), and continue stirring at constant temperature for 1.5 hours to obtain an organic carrier.

[0186] Based on an organic carrier mass fraction of 100 wt%, it comprises the following components by mass fraction:

[0187] 80 wt% terpineol;

[0188] Butyl carbitol acetate 7 wt%;

[0189] Ethyl cellulose 12.7 wt%;

[0190] Hexamethylene di-dodecyl stearamide 0.3 wt%;

[0191] (4) The organic carrier obtained in step (3) and the composite modified copper powder obtained in step (2) are added into a planetary mixing vessel. The planetary mixing vessel has a revolution speed of 20 rpm and a rotation speed of 40 rpm. The mixture is stirred for 50 min. Then, the modified glass powder obtained in step (1) is added into the planetary mixing vessel in three equal batches. After each addition, the mixture is stirred for 15 min to obtain a mixed slurry.

[0192] The mixed slurry is fed into a three-roll mill for rolling. Along the moving direction of the mixed slurry, the three-roll mill includes a feed roll, an intermediate roll, and a discharge roll. The gap between the feed roll and the intermediate roll is 25 μm, the gap between the intermediate roll and the gap between the discharge roll and the discharge roll is 7 μm. After rolling 10 times, a copper electronic paste for glass substrate is obtained.

[0193] Based on a weight fraction of 100 wt% for copper electronic paste used in glass-based printed circuits, it comprises the following components by mass fraction:

[0194] 75wt% composite modified copper powder;

[0195] Modified glass powder 3wt%;

[0196] Organic carrier 22wt%.

[0197] Example 4

[0198] This embodiment provides a method for preparing copper electronic paste for glass-based printed circuits, the preparation method specifically including the following steps:

[0199] (1) B2O3, Bi2O3, ZnO, SiO2, Al2O3, P2O5, TiO2, ZrO2, La2O3 and MoO3 were mixed in proportion and heated to melt at 1080℃ for 45 min to obtain glass melt. The glass melt was quenched with water and then dried at 140℃ to constant weight. Finally, after grinding and sieving, glass powder with a particle size D50 of 1.8 μm was obtained.

[0200] Based on a weight fraction of 100 wt% for the glass powder, it comprises the following components by weight fraction:

[0201] B2O3 31wt%

[0202] Bi2O3 32wt%

[0203] ZnO 21wt%

[0204] SiO2 11wt%

[0205] Al2O3 1.2 wt%

[0206] P2O5 0.5wt%;

[0207] TiO2 1.5wt%

[0208] ZrO2 1.2wt%

[0209] La2O3 0.3wt%

[0210] MoO3 0.3wt%

[0211] Under stirring and heating conditions at 65°C, polyethyleneimine was added to the glass powder at an amount of 0.35 wt% of the glass powder mass. After mixing for 18 min, isopropyl tris(dioctylphosphoyloxy)titanate was added at an amount of 0.45 wt% of the glass powder mass. Mixing was continued for 22 min, and then the mixture was dried at 140°C to constant weight to obtain modified glass powder.

[0212] (2) Linolenic acid and anhydrous ethanol were mixed evenly at a mass ratio of 1:22. Spherical copper powder with a particle size D50 of 180 nm was added. The mass ratio of spherical copper powder to linolenic acid was 11:1. The mixture was then ultrasonically dispersed at an ultrasonic power of 450 W for 22 min to obtain a dispersion. Tetrabutyl titanate was added to the dispersion under a nitrogen atmosphere and stirring conditions. The amount of tetrabutyl titanate added was 0.8 wt% of the mass of the spherical copper powder. After mixing evenly, deionized water was added dropwise. The amount of deionized water added was 1.8 wt% of the mass of tetrabutyl titanate. The mixture was then stirred and heated at 48 °C for 1.2 h. Finally, the mixture was centrifuged at 11500 rpm for 12 min to collect the precipitate. The precipitate was dried to constant weight under a nitrogen atmosphere and at 58 °C to obtain modified spherical copper powder.

[0213] Flake copper powder with a diameter D50 of 1.1 μm and a diameter-to-thickness ratio of 11:1 was placed in a fluidized bed. The flake copper powder was preheated to 95°C under a nitrogen atmosphere. A sodium silicate solution with a mass fraction of 4.5 wt% was sprayed onto the flake copper powder. The mass ratio of sodium silicate solution to flake copper powder was 1:75. After the sodium silicate solution was sprayed, the sprayed flake copper powder was heat-treated at 140°C for 12 min under a nitrogen atmosphere to obtain modified flake copper powder.

[0214] Under a nitrogen atmosphere, modified spherical copper powder and modified flake copper powder were mixed evenly at a mass ratio of 4.8:1 to obtain composite modified copper powder.

[0215] (3) After mixing terpineol and butyl carbitol acetate evenly, heat to 92°C. Add ethyl cellulose under stirring and heating at 92°C, and stir at constant temperature for 2.5 h. After the mixed solution cools down to 48°C, add polyamide wax thixotropic agent (hexamethylene bis(1-dodecyl)-hydroxystearamide), and continue stirring at constant temperature for 1.2 h to obtain an organic carrier.

[0216] Based on an organic carrier mass fraction of 100 wt%, it comprises the following components by mass fraction:

[0217] 80 wt% terpineol;

[0218] Butyl carbitol acetate 9.6 wt%;

[0219] 10 wt% ethyl cellulose

[0220] Hexamethylene di-dodecyl stearamide 0.4 wt%;

[0221] (4) The organic carrier obtained in step (3) and the composite modified copper powder obtained in step (2) are added into a planetary stirring vessel. The planetary stirring vessel has a revolution speed of 22 rpm and a rotation speed of 45 rpm. The mixture is stirred for 45 min. Then, the modified glass powder obtained in step (1) is added into the planetary stirring vessel in three equal batches. After each addition, the mixture is stirred for 12 min to obtain a mixed slurry.

[0222] The mixed slurry is fed into a three-roll mill for rolling. Along the moving direction of the mixed slurry, the three-roll mill includes a feed roll, an intermediate roll, and a discharge roll. The gap between the feed roll and the intermediate roll is 28 μm, the gap between the intermediate roll and the gap between the discharge roll and the discharge roll is 8 μm. After rolling 9 times, the copper electronic paste for glass substrate is obtained.

[0223] Based on a weight fraction of 100 wt% for copper electronic paste used in glass-based printed circuits, it comprises the following components by mass fraction:

[0224] 78wt% of composite modified copper powder;

[0225] 2wt% modified glass powder;

[0226] Organic carrier 20wt%.

[0227] Example 5

[0228] This embodiment provides a method for preparing copper electronic paste for glass-based printed circuits, the preparation method specifically including the following steps:

[0229] (1) B2O3, Bi2O3, ZnO, SiO2, Al2O3, P2O5, TiO2, ZrO2, La2O3 and MoO3 were mixed in proportion and heated to melt at 1100℃ for 40 min to obtain glass melt. The glass melt was quenched with water and then dried at 150℃ to constant weight. Finally, after grinding and sieving, glass powder with a particle size D50 of 2μm was obtained.

[0230] Based on a weight fraction of 100 wt% for the glass powder, it comprises the following components by weight fraction:

[0231] B2O3 32wt%

[0232] Bi2O3 30wt%

[0233] ZnO 22wt%

[0234] SiO2 12wt%

[0235] Al2O31wt%

[0236] P2O5 0.8wt%;

[0237] TiO2 1wt%

[0238] ZrO2 1wt%

[0239] La2O3 0.1wt%

[0240] MoO 30.1wt%

[0241] Under stirring and heating conditions at 70°C, polyethyleneimine was added to the glass powder at an amount of 0.4 wt% of the glass powder mass. After mixing for 15 min, isopropyl tris(dioctylphosphoyloxy)titanate was added at an amount of 0.5 wt% of the glass powder mass. The mixture was stirred for another 20 min and then dried at 150°C to constant weight to obtain modified glass powder.

[0242] (2) Lecithin and anhydrous ethanol were mixed evenly at a mass ratio of 1:25. Spherical copper powder with a particle size D50 of 200 nm was added. The mass ratio of spherical copper powder to lecithin was 12:1. The mixture was then ultrasonically dispersed at an ultrasonic power of 500 W for 20 min to obtain a dispersion. Tetrabutyl titanate was added to the dispersion under a nitrogen atmosphere and stirring conditions. The amount of tetrabutyl titanate added was 1 wt% of the mass of the spherical copper powder. After mixing evenly, deionized water was added dropwise. The amount of deionized water added was 2 wt% of the mass of tetrabutyl titanate. The mixture was then stirred and heated at 50 °C for 1 h. Finally, the mixture was centrifuged at 12000 rpm for 10 min to collect the precipitate. The precipitate was dried to constant weight under a nitrogen atmosphere and at 60 °C to obtain modified spherical copper powder.

[0243] Flake copper powder was placed in a fluidized bed. The diameter (D50) of the flake copper powder was 1.2 μm and the diameter-to-thickness ratio was 12:1. The flake copper powder was preheated to 100°C under a nitrogen atmosphere. A sodium silicate solution with a mass fraction of 5 wt% was sprayed onto the flake copper powder. The mass ratio of sodium silicate solution to flake copper powder was 1:80. After the sodium silicate solution was sprayed, the sprayed flake copper powder was heat-treated at 150°C under a nitrogen atmosphere for 10 min to obtain modified flake copper powder.

[0244] Under a nitrogen atmosphere, modified spherical copper powder and modified flake copper powder were mixed evenly at a mass ratio of 5:1 to obtain composite modified copper powder.

[0245] (3) After mixing terpineol and butyl carbitol acetate evenly, heat to 95°C. Add ethyl cellulose under stirring and heating at 95°C, and stir at constant temperature for 2 hours. After the mixed solution cools down to 50°C, add polyamide wax thixotropic agent (hexamethylene bis(1-dodecyl)-hydroxystearamide), and continue stirring at constant temperature for 1 hour to obtain an organic carrier.

[0246] Based on an organic carrier mass fraction of 100 wt%, it comprises the following components by mass fraction:

[0247] 80 wt% terpineol;

[0248] Butyl carbitol acetate 5 wt%;

[0249] Ethyl cellulose 14.6 wt%;

[0250] Hexamethylene di-dodecyl stearamide 0.4 wt%;

[0251] (4) The organic carrier obtained in step (3) and the composite modified copper powder obtained in step (2) are added into a planetary mixing vessel. The planetary mixing vessel has a revolution speed of 25 rpm and a rotation speed of 50 rpm. The mixture is stirred for 40 min. Then, the modified glass powder obtained in step (1) is added into the planetary mixing vessel in three equal batches. After each addition, the mixture is stirred for 10 min to obtain a mixed slurry.

[0252] The mixed slurry is fed into a three-roll mill for rolling. Along the moving direction of the mixed slurry, the three-roll mill includes a feed roll, an intermediate roll, and a discharge roll. The gap between the feed roll and the intermediate roll is 30 μm, the gap between the intermediate roll and the gap between the discharge roll and the discharge roll is 10 μm. After rolling 8 times, the copper electronic paste for glass substrate is obtained.

[0253] Based on a weight fraction of 100 wt% for copper electronic paste used in glass-based printed circuits, it comprises the following components by mass fraction:

[0254] 80wt% of composite modified copper powder;

[0255] Modified glass powder 5wt%;

[0256] Organic carrier 15wt%.

[0257] Comparative Example 1

[0258] This comparative example provides a method for preparing copper electronic paste for glass-based printed circuits. The difference from Example 1 is that in step (1), the amount of polyethyleneimine added is adjusted to 0.1 wt% of the glass powder mass. Other operating steps and process parameters are exactly the same as in Example 1.

[0259] Comparative Example 2

[0260] This comparative example provides a method for preparing copper electronic paste for glass-based printed circuits. The difference from Example 1 is that in step (1), the amount of polyethyleneimine added is adjusted to 0.6 wt% of the glass powder mass. Other operating steps and process parameters are exactly the same as in Example 1.

[0261] Comparative Example 3

[0262] This comparative example provides a method for preparing copper electronic paste for glass-based printed circuits. The difference from Example 1 is that in step (1), the amount of isopropyltris(dioctylphosphoyloxy)titanate added is adjusted to 0.1 wt% of the glass powder mass. Other operating steps and process parameters are exactly the same as in Example 1.

[0263] Comparative Example 4

[0264] This comparative example provides a method for preparing copper electronic paste for glass-based printed circuits. The difference from Example 1 is that in step (1), the amount of isopropyltris(dioctylphosphoyloxy)titanate added is adjusted to 0.8 wt% of the glass powder mass. Other operating steps and process parameters are exactly the same as in Example 1.

[0265] Comparative Example 5

[0266] This comparative example provides a method for preparing copper electronic paste for glass-based printed circuits. The difference from Example 1 is that in step (1), the amount of tetraisopropyl titanate added is adjusted to 0.1 wt% of the mass of spherical copper powder. Other operating steps and process parameters are exactly the same as in Example 1.

[0267] Comparative Example 6

[0268] This comparative example provides a method for preparing copper electronic paste for glass-based printed circuits. The difference from Example 1 is that in step (2), the amount of tetraisopropyl titanate added is adjusted to 1.5 wt% of the mass of spherical copper powder. Other operating steps and process parameters are exactly the same as in Example 1.

[0269] Comparative Example 7

[0270] This comparative example provides a method for preparing copper electronic paste for glass-based printed circuits. The difference from Example 1 is that in step (2), the mass ratio of sodium silicate solution to flake copper powder is adjusted to 1:50. Other operating steps and process parameters are exactly the same as in Example 1.

[0271] Comparative Example 8

[0272] This comparative example provides a method for preparing copper electronic paste for glass-based printed circuits. The difference from Example 1 is that in step (2), the mass ratio of sodium silicate solution to flake copper powder is adjusted to 1:100. Other operating steps and process parameters are exactly the same as in Example 1.

[0273] Comparative Example 9

[0274] This comparative example provides a method for preparing copper electronic paste for glass-based printed circuits. The difference from Example 1 is that in step (2), the mass ratio of modified spherical copper powder and modified flake copper powder is adjusted to 2:1. Other operating steps and process parameters are exactly the same as in Example 1.

[0275] Comparative Example 10

[0276] This comparative example provides a method for preparing copper electronic paste for glass-based printed circuits. The difference from Example 1 is that in step (2), the mass ratio of modified spherical copper powder to modified flake copper powder is adjusted to 8:1. Other operating steps and process parameters are exactly the same as in Example 1.

[0277] Comparative Example 11

[0278] This comparative example provides a method for preparing copper electronic paste for glass-based printed circuits. The difference from Example 1 is that in step (2), only the glass powder is modified with polyethyleneimine, and the modification with phosphate coupling agent is omitted. Other operation steps and process parameters are exactly the same as in Example 1.

[0279] Comparative Example 12

[0280] This comparative example provides a method for preparing copper electronic paste for glass-based printed circuits. The difference from Example 1 is that in step (1), only the glass powder is modified with a phosphate coupling agent, and the polyethyleneimine modification is omitted. Other operation steps and process parameters are exactly the same as in Example 1.

[0281] Comparative Example 13

[0282] This comparative example provides a method for preparing copper electronic paste for glass-based printed circuits. The difference from Example 1 is that in step (1), the modification treatment of glass powder with polyethyleneimine and phosphate coupling agent is omitted, and unmodified glass powder is used. Other operation steps and process parameters are exactly the same as in Example 1.

[0283] Comparative Example 14

[0284] This comparative example provides a method for preparing copper electronic paste for glass-based printed circuits. The difference from Example 1 is that in step (2), the modification of spherical copper powder with organic titanate is omitted, and unmodified spherical copper powder is used. Other operation steps and process parameters are exactly the same as in Example 1.

[0285] Comparative Example 15

[0286] This comparative example provides a method for preparing copper electronic paste for glass-based printed circuits. The difference from Example 1 is that in step (2), the modification of the flake copper powder with sodium silicate solution is omitted, and unmodified flake copper powder is used. Other operation steps and process parameters are exactly the same as in Example 1.

[0287] Application examples

[0288] This application example provides a method for using copper electronic paste on a glass substrate, specifically including the following steps:

[0289] (1) Substrate pretreatment

[0290] The glass substrate was ultrasonically cleaned with deionized water to remove surface contaminants such as grease and dust, and then dried in an oven at 150°C for 20 minutes to completely remove moisture.

[0291] (2) Slurry preparation

[0292] Before use, stir the copper electronic paste prepared in the examples and comparative examples at low speed for 20 minutes to ensure that the components are evenly dispersed and there is no sedimentation.

[0293] (3) Screen printing

[0294] Copper electronic paste was printed onto a glass substrate using a 300-mesh stainless steel screen, resulting in a wet film thickness of 20 μm.

[0295] (4) Drying

[0296] After printing, let it stand at room temperature for 5 minutes to allow the paste to flow naturally and eliminate the screen pattern. Then, place the printed glass substrate in a hot air circulating oven and dry it at 150°C for 10 minutes.

[0297] (5) Sintering

[0298] The dried glass substrate is then placed into a sintering furnace for sintering. The entire sintering process is carried out in a high-purity nitrogen environment and consists of three stages: preheating, binder removal, and sintering. The specific operating parameters are as follows:

[0299] During the preheating stage, the temperature is increased from room temperature to 250℃ at a rate of 10℃ / min. After reaching 250℃, no heat preservation is performed.

[0300] During the glue removal stage, the temperature is increased from 250℃ to 450℃ at a rate of 5℃ / min, and no heat preservation is performed after reaching 450℃.

[0301] During the sintering stage, the temperature is increased from 450℃ to 750℃ at a rate of 15℃ / min, and then held at 750℃ for 15min.

[0302] After the sintering stage, the substrate is cooled to below 150°C in the furnace and then removed, ultimately forming a conductive film layer on the glass substrate.

[0303] Using the method provided in the application examples, the copper electronic pastes prepared in Examples 1-5 and Comparative Examples 1-15 were used to prepare corresponding conductive films. The sheet resistance, sheet resistance change rate, and adhesion of the conductive films were tested. The specific test steps are as follows:

[0304] (1) Square resistance

[0305] The sheet resistance (Ω / □) of the conductive film layer was tested in accordance with the national standard GB / T 17473.3-2008 "Test Method for Precious Metal Pastes for Microelectronics Technology - Determination of Sheet Resistance".

[0306] (2) Rate of change of sheet resistance

[0307] The sheet resistance of the conductive film was tested according to the national standard GB / T 17473.3-2008 "Test Method for Precious Metal Paste for Microelectronics Technology - Determination of Sheet Resistance". The conductive film was then placed in an environment of 85℃ / 85% relative humidity for 168 hours, and the sheet resistance of the conductive film was tested again. The change rate (%) of the sheet resistance of the conductive film under high temperature and high humidity environment was calculated.

[0308] (3) Adhesion

[0309] The adhesion (MPa) between the conductive film layer and the glass substrate was tested in accordance with the national standard GB / T 17473.4-2008 "Test Method for Adhesion Determination of Noble Metal Pastes for Microelectronics Technology".

[0310] The test results are shown in Table 1.

[0311] Table 1. Performance test results of conductive films prepared from copper electronic pastes in Examples 1-5 and Comparative Examples 1-15.

[0312]

[0313] The test data from Example 1, Comparative Example 1, and Comparative Example 2 show that when the amount of polyethyleneimine added is insufficient, a complete organic coating layer cannot be formed on the surface of the glass powder. This results in poor dispersion of the glass powder in the organic carrier, making it prone to agglomeration. This not only affects the uniformity of the slurry but also makes the wetting and spreading of the molten glass relative to the copper powder and substrate insufficient during sintering, thus causing a decrease in the adhesion and conductivity of the film layer. When excessive polyethyleneimine is added, the excessively thick organic coating layer decomposes during sintering, generating more gas and forming microscopic defects inside the film layer. These defects hinder electron transport and reduce the density of the film layer, leading to a decrease in the conductivity of the film layer.

[0314] As can be seen from the test data of Example 1 and Comparative Examples 3-8, adjusting the amount of organic titanate or silicate directly affects the antioxidant effect of copper powder. When the amount of organic titanate is insufficient, the coating layer on the surface of spherical copper powder is incomplete, and the copper powder is easily oxidized, forming high-resistivity copper oxide, which leads to an increase in the sheet resistance of the film. Oxidation is aggravated in high-temperature and high-humidity environments, and the rate of change of sheet resistance increases. When the amount of organic titanate is excessive, the overly thick coating layer will hinder the effective electrical connection between copper powder particles during sintering, leading to an increase in the sheet resistance of the film. When the amount of silicate is insufficient, the silicate coating layer on the surface of the flake copper powder is too thin, which cannot provide sufficient antioxidant protection for the copper powder, making the copper powder easy to oxidize. When the amount of silicate is excessive, the silicate coating layer is too thick, which hinders the effective electrical connection between flake copper powder and between it and spherical copper powder, leading to a decrease in the conductivity of the film.

[0315] The test data from Examples 1, 9, and 10 show that when the proportion of spherical copper powder is too low, the gaps between the flake copper powder cannot be effectively filled, resulting in poor film density and increased sheet resistance. When the proportion of spherical copper powder is too high, the amount of flake copper powder is too low, making it difficult to construct an efficient long-range conductive path, and increasing the sheet resistance of the film.

[0316] As can be seen from the test data of Example 1 and Comparative Examples 11-13, the cancellation of the modification of the glass powder directly destroys the interfacial compatibility between the binder phase, the organic carrier, and the conductive phase, resulting in uneven dispersion of the glass powder. During sintering, the molten glass does not wet and spread the copper powder sufficiently, which seriously affects the interfacial bonding between the film and the substrate. At the same time, the discontinuous glass phase also causes defects in the conductive network, increasing the sheet resistance of the film.

[0317] As can be seen from the test data of Example 1, Comparative Example 14 and Comparative Example 15, the removal of the modification treatment of copper powder makes the copper powder very easy to be oxidized during the preparation process, forming a high-resistivity oxide layer on the surface, which hinders the effective electrical connection between copper powder particles. This not only causes a decrease in the conductivity of the film layer, but also causes a decrease in the resistance stability of the film layer due to continuous oxidation in a humid and hot environment.

[0318] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A copper electronic paste for glass-based printed circuits, characterized in that, The copper electronic paste for glass-based printed circuits includes composite modified copper powder, modified glass powder, and an organic carrier. The composite modified copper powder is composed of modified spherical copper powder and modified flake copper powder. The modified spherical copper powder is obtained by modifying spherical copper powder with organic titanate, and the modified flake copper powder is obtained by modifying flake copper powder with silicate. The modified glass powder is obtained by modifying glass powder with polyethyleneimine and phosphate ester coupling agent. The glass powder is obtained by mixing B2O3, Bi2O3, ZnO, SiO2, Al2O3, P2O5, TiO2, ZrO2, La2O3 and MoO3 and then melting, water quenching, drying and grinding. The organic carrier includes terpineol, butyl carbitol acetate, ethyl cellulose, and a thixotropic agent.

2. The copper electronic paste for glass-based printed circuits according to claim 1, characterized in that, Based on a weight fraction of 100 wt% for the copper electronic paste used in glass-based printed circuits, it comprises the following components by mass fraction: 70-80 wt% of composite modified copper powder; Modified glass powder 2~5wt%; Organic carrier 15~25wt%.

3. The copper electronic paste for glass-based printed circuits according to claim 1, characterized in that, Based on a weight fraction of 100 wt% for the glass powder, it comprises the following components by weight fraction: B2O3 28~32wt%; Bi₂O₃ 30~35wt%; ZnO 18~22wt%; SiO2 8~12wt%; Al2O3 1~2wt% P2O5 0.5~1.5wt%; TiO2 1~2wt%; ZrO2 1~2wt%; La2O3 0.1~1wt% MoO3 0.1~0.5wt%.

4. The copper electronic paste for glass-based printed circuits according to claim 1, characterized in that, Based on a mass fraction of 100 wt% for the organic carrier, it comprises the following components by mass fraction: 70-80 wt% terpineol Butyl carbitol acetate 5~10 wt%; Ethyl cellulose 10~20wt%; Thixotropic agent 0.2~0.4wt%.

5. A method for preparing a copper electronic paste for glass-based printed circuits according to any one of claims 1 to 4, characterized in that, The preparation method includes: (I) B2O3, Bi2O3, ZnO, SiO2, Al2O3, P2O5, TiO2, ZrO2, La2O3 and MoO3 are mixed and melted in proportion to obtain a glass melt. The glass melt is then water-quenched, dried and ground to obtain glass powder. Under stirring and heating conditions, polyethyleneimine and phosphate coupling agent are added to the glass powder, and the modified glass powder is obtained after drying. (II) After mixing the dispersant with anhydrous ethanol, spherical copper powder is added and ultrasonically dispersed to obtain a dispersion. Under a nitrogen atmosphere and stirring conditions, an organic titanate is added to the dispersion, followed by the addition of deionized water. The mixture is stirred, heated, and centrifuged. The precipitate is then dried to obtain modified spherical copper powder. Flake copper powder is placed in a fluidized bed and preheated under a nitrogen atmosphere. A silicate solution is sprayed onto the flake copper powder, followed by heat treatment to obtain modified flake copper powder. Under a nitrogen atmosphere, the modified spherical copper powder and the modified flake copper powder are mixed to obtain composite modified copper powder. (III) Mix terpineol and butyl carbitol acetate evenly, add ethyl cellulose under stirring and heating conditions, then cool down, add thixotropic agent under stirring conditions, and continue stirring to obtain an organic carrier; (IV) The organic carrier is mixed with the composite modified copper powder to obtain an intermediate slurry. The modified glass powder is added to the intermediate slurry in batches to obtain a mixed slurry. The mixed slurry is fed into a roller press for rolling to obtain the glass substrate copper electronic paste.

6. The method for preparing copper electronic paste for glass-based printed circuits according to claim 5, characterized in that, In (I), the melting temperature is 1000~1100℃; The melting time is 40-60 minutes; The particle size D50 of the glass powder is 1~2μm; Under stirring and heating conditions of 50~70℃, polyethyleneimine is added to the glass powder, and after mixing for 15~25 min, a phosphate coupling agent is added, and mixing continues for 20~30 min. The amount of polyethyleneimine added is 0.2~0.4 wt% of the mass of the glass powder; The amount of the phosphate coupling agent added is 0.3~0.5 wt% of the mass of the glass powder.

7. The method for preparing a copper electronic paste for glass-based printed circuits according to claim 5, characterized in that, In (II), the mass ratio of the dispersant to the anhydrous ethanol is 1:(15~25); The particle size D50 of the spherical copper powder is 100~200nm; The mass ratio of the spherical copper powder to the dispersant is (8~12):1; The amount of the organic titanate added is 0.5~1wt% of the mass of the spherical copper powder; The amount of deionized water added is 1-2 wt% of the mass of the organic titanate. The mixing and heating temperature is 40~50℃; The mixing and heating time is 1-2 hours.

8. The method for preparing copper electronic paste for glass-based printed circuits according to claim 5, characterized in that, In (II), the diameter D50 of the flake copper powder is 0.8~1.2μm; The aspect ratio of the flaky copper powder is (8~12):1; The flake copper powder is placed in a fluidized bed and preheated to 80-100°C in a nitrogen atmosphere; The silicate solution has a mass fraction of 3-5 wt%; The mass ratio of the silicate solution to the flake copper powder is 1:(60~80); The heat treatment is performed at 120~150℃ for 10~20 min; The mass ratio of the modified spherical copper powder to the modified flake copper powder is (4~5):

1.

9. A method for preparing copper electronic paste for glass-based printed circuits according to claim 5, characterized in that, In (III), the terpineol and butyl carbitol acetate are mixed evenly and heated to 85~95°C. Ethyl cellulose is added under stirring and heating conditions, and the mixture is stirred at a constant temperature for 2~4 hours. After cooling to 40-50℃, add the thixotropic agent and continue stirring at a constant temperature for 1-2 hours. The thixotropic agent is a polyamide wax-based thixotropic agent.

10. A method for preparing a copper electronic paste for glass-based printed circuits according to claim 5, characterized in that, In (IV), the organic carrier and the composite modified copper powder are mixed in a planetary stirred tank; The modified glass powder is added to the planetary stirred tank in 2-3 equal portions, and mixed for 10-20 minutes after each addition. The mixed slurry is rolled in a three-roll mill, which includes a feed roll, an intermediate roll, and a discharge roll. The gap between the feed roll and the intermediate roll is greater than the gap between the discharge roll and the discharge roll. The gap between the feed rollers is 20~30μm; The gap between the intermediate rollers is 10~20μm; The gap between the discharge rollers is 5~10μm; The mixed slurry is rolled 8 to 12 times in the three-roll mill.

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