Conductive Paste, Preparation Method Thereof, and Electronic Device Comprising the Same

Abstract

The present invention relates to a conductive paste, a preparation method thereof, and an electronic device comprising the same, belonging to the technical field of electronic pastes. A conductive paste, calculated by mass parts, comprises the following components: 30-90 parts of a conductive component, 3-15 parts of a resin, 10-65 parts of a solvent, and 0.1-5 parts of an auxiliary agent; wherein, the conductive component comprises a conductive main component and a conductive stretching component, and the mass ratio of the conductive main component to the conductive stretching component is (30-97):(3-70); the conductive main component comprises at least one of a silver-containing material or a copper-containing material; the conductive stretching component comprises at least one of a nano- or micro-scale metal material, a carbon material, or a polymer-coated conductive material. The present invention can improve the flexibility of the conductive paste, and at the same time has excellent conductive performance, can overcome the problem that the resistivity changes greatly when the conventional paste in the prior art is stretched, and has good application prospects.

Description

Technical Field

[0001] The present invention belongs to the technical field of electronic pastes, and in particular relates to a conductive paste, a preparation method and an electronic device containing the conductive paste. Background Art

[0002] In recent years, with the continuous development of electronic technology, more and more products and equipment have put forward higher requirements for the miniaturization and flexibility of electronic devices. At the same time, more products and equipment, including daily necessities, have also put forward the demand for electronic or chip-based, which has given rise to the demand for conductive pastes of various dimensions on different substrates. For example, with the advancement of Internet of Things packaging, flexible wearable devices, augmented reality devices, virtual augmented devices, flexible sensors, etc., higher demands and requirements have been put forward for high conductivity, high bending, and high stretchability that are lower than conductive pastes.

[0003] In the relevant technology, the mainstream flexible conductive pastes at this stage can be divided into three categories. The first type is polymer paste, and the main products at this stage are PEDOT (PEDOT is a polymer of EDOT (3,4-ethylenedioxythiophene monomer)): PSS (polystyrene sulfonic acid). The ductility of polymer materials has great advantages, but their conductivity is relatively mediocre, and can only reach the level of tens or hundreds of Ω / □. It is difficult to meet the electrical performance requirements for most applications. The second type is pure inorganic metal paste. The main products at this stage are liquid gallium and its liquid alloys. Liquid metal has the better conductivity of metal and certain ductility. However, its high price makes it difficult to use in mass-produced products, and its application is limited. The third type is a slurry that combines inorganic metals and polymers. The inorganic metal can provide better conductivity, and the polymer can provide certain flexibility. However, the problem with this type of slurry is that under a certain tensile strength, the resistance tends to rise sharply, and the flexibility of the polymer is not well transmitted to the inorganic metal, resulting in the resistance increasing by more than 2 times when stretched to a certain extent, such as 20%, making it difficult to meet certain high tensile requirements. Summary of the invention

[0004] In view of the above problems, the present invention aims to solve one of the technical problems in the related art to at least a certain extent. To this end, the present invention provides a conductive paste, a preparation method and an electronic device containing the same, which can improve the flexibility of the conductive paste and have better conductivity, and can overcome the problem of high resistance change of conventional paste in the prior art when stretched.

[0005] As one aspect of the present invention, it relates to a conductive paste, which comprises the following components in parts by mass:

[0006] 30 to 90 parts of a conductive component, 3 to 15 parts of a resin, 10 to 65 parts of a solvent, and 0.1 to 5 parts of an additive; wherein, the conductive component includes a conductive main component and a conductive stretching component, and the mass ratio of the conductive main component to the conductive stretching component is (30 to 97):(3 to 70); the conductive main component includes at least one of a silver-containing material or a copper-containing material; the conductive stretching component includes at least one of a nano- or micro-scale metal material, a carbon material, or a polymer-coated conductive material.

[0007] In some embodiments, by mass parts, it includes the following components: 50 to 85 parts of a conductive component, 4 to 12 parts of a resin, 12 to 50 parts of a solvent, and 0.5 to 2 parts of an additive. In some embodiments, by mass parts, it includes the following components: 60 to 84 parts of a conductive component, 4 to 10 parts of a resin, 15 to 45 parts of a solvent, and 0.8 to 1.5 parts of an additive.

[0008] In some embodiments, the mass ratio of the conductive main component to the conductive stretching component is (50 to 96):(4 to 50). In some embodiments, the mass ratio of the conductive main component to the conductive stretching component is (60 to 90):(10 to 40).

[0009] In some embodiments, the conductive main component includes at least one of silver powder, copper powder, or silver-coated copper powder.

[0010] In some embodiments, the silver powder includes at least one of spherical silver powder, flaky silver powder, rod-shaped silver powder, or wire-shaped silver powder.

[0011] In some embodiments, the silver powder is micro-scale silver powder, the copper powder is micro-scale copper powder, and the silver-coated copper powder is micro-scale silver-coated copper powder.

[0012] In some embodiments, the nano- or micro-scale metal material includes at least one of silver nano- or micro-materials, copper nano- or micro-materials, silver-coated copper nano- or micro-materials, gold nano- or micro-materials, gold-coated copper nano- or micro-materials, or gold-coated silver nano- or micro-materials.

[0013] In some embodiments, the carbon material includes at least one of graphene, graphene oxide, reduced graphene oxide, chemically functionalized graphene, carbon nanotubes, or carbon fibers.

[0014] In some embodiments, the polymer-coated conductive material is core-shell shaped, with the core layer being a conductive material and the shell layer being a polymer material.

[0015] In some embodiments, the conductive stretching component further includes MXene.

[0016] In some of these embodiments, the morphology of the nano- or micro-scale metal material includes at least one of sheet-like, linear, rod-like, core-shell-like, or cluster-like.

[0017] In some of these embodiments, the conductive material includes at least one of nano silver wires, silver powder, copper powder, silver-coated copper powder, graphene, or carbon nanotubes.

[0018] In some of these embodiments, the polymer material includes at least one of polyethylene glycol (PEG), polylactic acid (PLA), polyvinylpyrrolidone (PVP), polyacrylic acid (PAA), polyvinyl alcohol (PVA), polyethylene oxide (PEO), poly-L-lactide (PLLA), polycaprolactone (PCL), polyacrylonitrile (PAN), or polymethyl methacrylate (PMMA).

[0019] In some of these embodiments, the number-average molecular weight of the resin is ≥1000.

[0020] In some of these embodiments, the boiling point of the solvent is ≥100 °C.

[0021] In some of these embodiments, the resin includes at least one of TPU resin, polyester resin, acrylic resin, amino resin, silicone resin, or epoxy resin.

[0022] In some of these embodiments, the solvent includes at least one of DBE, MDBE, ethylene glycol, dimethylformamide, diethylene glycol dimethyl ether, ethylene glycol monomethyl ether, diethylene glycol butyl ether acetate, diethylene glycol butyl ether, octanol, octyl acetate, xylene, terpineol, or isophorone.

[0023] In some of these embodiments, the additives include at least one of a wetting and dispersing agent, an antifoaming agent, a promoter, a tackifier, a surfactant, a coupling agent, a formability regulator, or a curing regulator.

[0024] As another aspect of the present invention, it relates to a preparation method for preparing the above conductive paste. The preparation method of the conductive paste includes:

[0025] Stir and mix the formula amounts of the conductive main component, the conductive stretching component, the resin, the solvent, and the additives to obtain the conductive paste.

[0026] As another aspect of the present invention, it relates to an electronic device. The electronic device includes a substrate and a conductive circuit formed on the substrate. The conductive circuit is prepared from the conductive paste as described above.

[0027] In some of these embodiments, the thickness of the substrate is 20 μm to 500 μm.

[0028] In some of these embodiments, the material of the substrate includes at least one of polydimethylsiloxane (PDMS), thermoplastic polyurethane elastomer rubber (TPU), polyethylene terephthalate (PET), polyethylene (PE), silica gel, polyester, or acrylate.

[0029] In some of these embodiments, the method for preparing the conductive circuit includes: printing the conductive paste on the substrate and curing it to obtain the conductive circuit.

[0030] In some of these embodiments, the curing temperature is 110 - 160 °C and the time is 10 - 30 min.

[0031] Compared with the prior art, the technical solution of the present application has at least the following beneficial effects:

[0032] The conductive paste provided by the present application includes a conductive component, a resin, a solvent, and an additive. The conductive component includes a certain proportion of a conductive main component and a conductive stretching component. The conductive main component includes one or more of silver-containing materials or copper-containing materials, and the conductive stretching component includes one or more of nano- or micro-scale metal materials, carbon materials, or polymer-coated conductive materials. Thus, by using an efficient conductive material as the conductive main component, the initial resistivity can be reduced, so that when stretched and bent, the change in resistivity is relatively small. And by compounding a conductive material with high stretching performance as the conductive stretching component, the resistivity in the stretched state can be ensured. For example, a relatively excellent resistivity can still be maintained at a stretching rate of 50%. At the same time, by optimizing the ratio of the conductive main component and the conductive stretching component, the conductive performance and stretching performance of the finally obtained conductive paste can meet the requirements of the general conductive electronics industry.

[0033] The method of the present invention is simple and easy to implement, easy to operate, and easy to achieve large-scale production. Moreover, the prepared conductive paste has a low resistance change rate when stretched and bent. On the premise of ensuring the conductive performance of the conductive paste, the service life and reliability of electronic devices can be improved, and it has good application prospects.

[0034] Additional aspects and advantages of the embodiments of the present application will be partially described, shown, or elucidated by the implementation of the embodiments of the present application in the following description. Detailed Embodiments

[0035] The following will further elaborate on the present application in conjunction with specific embodiments. It should be understood that these embodiments of the present application are only used to illustrate the present application and not to limit the scope of the present application.

[0036] The endpoints and any values in the ranges disclosed herein are not limited to the exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range or individual point values, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0037] In this article, unless otherwise specified, the percentages, ratios or parts involved are by mass. Among them, "parts by mass" refers to the basic measurement unit of the mass ratio relationship of multiple components. 1 part can represent any unit mass. For example, 1 part can be expressed as 1 g, can be expressed as 1.68 g, or can also be expressed as 5 g, etc. In this article, if there is no special indication, the percentage (%) refers to the mass percentage relative to the composition.

[0038] In view of the fact that the resistance of the conductive paste in the related art increases sharply when stretched or bent, and it cannot meet the requirement of low resistance change of the conductive paste during stretching or bending. In other words, the existing conductive paste cannot have good flexibility or ductility while ensuring excellent conductive performance. The embodiments of the present application provide an improved conductive paste, which can improve the flexibility of the conductive paste and at the same time have relatively excellent conductive performance.

[0039] In the first aspect of the present application, a conductive paste is provided. By mass, the conductive paste includes the following components: 30-90 parts of a conductive component, 3-15 parts of a resin, 10-65 parts of a solvent, and 0.1-5 parts of an additive;

[0040] Among them, the conductive component includes a conductive main component and a conductive stretching component, and the mass ratio of the conductive main component to the conductive stretching component is (30-97):(3-70); the conductive main component includes at least one of a silver-containing material or a copper-containing material; the conductive stretching component includes at least one of a nano- or micro-scale metal material, a carbon material, or a polymer-coated conductive material.

[0041] According to the embodiments of the present application, for the provided conductive paste, by adding a certain amount of flexible polymer, especially a polymer with a larger molecular weight, fewer rigid structures, and more straight chains, it can effectively provide a certain stretching and bending performance at the polymer end. Exemplarily, the conductive paste contains a resin, and resin materials such as specific TPU (thermoplastic polyurethane elastomer rubber) resin, polyester resin, and epoxy resin can be selected.

[0042] According to the embodiments of the present application, the provided conductive paste, by adding a conductive material with relative flexibility, that is, a conductive stretching component, has a flexible conductive material, which can minimize the loss of link sites in the stretched state, thus basically not affecting the conductive efficiency. For example, one-dimensional or two-dimensional nano-conductive materials can be selected, such as nano silver flakes, nano silver wires, or carbon materials such as graphene and carbon nanotubes. Further, the conductive stretching component in this embodiment includes a polymer-coated conductive material. By adding a flexible polymer-inorganic conductive composite material, with the polymer material as the shell layer and the inorganic conductive material as the core layer, and the polymer material completely or partially coating the inorganic conductive material, the conductive performance can be improved. At the same time, during the stretching process, only the polymer material is stretched, and the conductive material still maintains its high conductive performance.

[0043] It should be understood that the conductive material in the above polymer-coated conductive material is preferably an inorganic conductive material. By the way of compounding the inorganic conductive material and the organic polymer material, not only can the conductive performance be improved, but also a smaller resistance change rate can be achieved during stretching or bending.

[0044] Thus, based on the above settings, the conductive paste of this embodiment can meet the requirement of low resistance change of the conductive paste during stretching or bending. For example, it has been experimentally proven that the conductive paste provided in this embodiment can have a resistance change rate of 100-150% under a 50% tensile deformation; at the same time, under a bending radius of R5, after ten thousand bends, the resistance change rate <20%, so as to meet the needs of most flexible stretchable conductive circuits and have good application prospects.

[0045] In this embodiment, among the above conductive stretching components, the nano- or micro-scale metal material is preferably a nano-scale metal material. The above conductive stretching component at least includes a polymer-coated conductive material, and may also include optional nano- or micro-scale metal materials and carbon materials. That is, it is more preferable to use the polymer-coated conductive material as the conductive stretching component. In addition, the conductive stretching component may or may not add nano- or micro-scale metal materials and / or carbon materials.

[0046] It should be noted that the present invention does not limit the sources of the various components in the conductive paste, such as the conductive component, resin, solvent, additives, etc., which can be prepared by oneself or obtained through commercial purchase.

[0047] In order to achieve better cooperation among the components in the conductive paste, have better flexibility and better conductivity. The conductive paste includes 30 to 90 parts by mass of a conductive component. Typically but not restrictively, for example, it can be 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, 75 parts, 80 parts, 85 parts, 90 parts, and any value within the range formed by any two of these point values. As the core of the conductivity of the conductive paste, the conductive component generally accounts for about 30% to 90% or about 30% to 85% of the paste. If the content of the conductive component is too low, the conductive function is difficult to achieve. If the content of the conductive component is too high, the tensile properties and cost are difficult to meet the requirements. Therefore, by making the addition amount of the conductive component 30 to 90 parts, certain tensile properties can be satisfied while ensuring the conductive function, and the cost can be reduced.

[0048] The conductive paste includes 3 to 15 parts by mass of a resin. Typically but not restrictively, for example, it can be 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, and any value within the range formed by any two of these point values. As the key to the tensile properties, the flexible resin generally has an addition amount of about 3% to 15%. If the addition amount of the resin is too low, the tensile function is difficult to meet. If the addition amount of the resin is too high, too much conductor material is coated, resulting in too large a resistance and difficulty in realizing the application. Therefore, by making the addition amount of the resin 3 to 15 parts, both the conductive performance and the tensile performance can be taken into account.

[0049] The conductive paste includes 10 to 65 parts by mass of a solvent. Typically but not restrictively, for example, it can be 10 parts, 12 parts, 14 parts, 15 parts, 18 parts, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, 65 parts, and any value within the range formed by any two of these point values. In the conductive paste, the solvent is generally used to adjust the viscosity and printing performance, and the addition amount is generally 10% to 65%. If the addition amount of the solvent is too small, the printing performance is difficult to guarantee. If the addition amount of the solvent is too large, the content of the main effective components is too low, and functions such as conductivity are difficult to achieve. The conductive paste includes 0.1 to 5 parts by mass of an auxiliary agent. Typically but not restrictively, for example, it can be 0.1 part, 0.2 part, 0.5 part, 1 part, 1.2 part, 1.5 part, 2 parts, 3 parts, 4 parts, 5 parts, and any value within the range formed by any two of these point values. In the conductive paste, the auxiliary agent is mainly used to improve the printing performance and other comprehensive properties, and the addition amount of the auxiliary agent is relatively small in the conductive paste.

[0050] The formulation of the conductive paste in this embodiment mainly consists of four parts, namely, a conductive component, a resin, a solvent, and an additive. According to different objectives and uses, the addition amounts and types of each component are also different. By adjusting the types and ratios of the raw material components of the conductive paste and synergistically acting with other components, when each component is within the above ranges, the prepared conductive paste can have good flexibility, good conductivity, and stable performance, and can meet the requirement of low change rate of the resistance of the conductive paste during stretching or bending.

[0051] The conductive paste provided by the present invention can be applied in flexible electronic devices, such as in devices like chips and battery chips. During the possible flexible stretching or folding process of flexible electronic devices, the quality of the conductive paste will directly determine the service life of the device, which poses relatively high technical requirements for the material flexibility, durability, or conductivity, etc. of the conductive paste. The conductive paste provided by the present invention fully considers the characteristic requirements of flexible electronic devices. Its various components cooperate with each other, making the molecular chains of the organic components inside the paste have large flexibility, excellent material toughness, and excellent conductivity, which helps to improve the life and reliability of electronic devices.

[0052] The following are the preferred technical solutions of the present invention, but do not limit the technical solutions provided by the present invention. Through the following preferred technical solutions, the technical objectives and beneficial effects of the present invention can be better achieved and realized.

[0053] In some embodiments, by mass, the conductive paste includes the following components: 50 - 85 parts of a conductive component, 4 - 12 parts of a resin, 12 - 50 parts of a solvent, and 0.5 - 2 parts of an additive.

[0054] In some embodiments, by mass, the conductive paste includes the following components: 60 - 84 parts of a conductive component, 4 - 10 parts of a resin, 15 - 45 parts of a solvent, and 0.8 - 1.5 parts of an additive.

[0055] By reasonably adjusting and optimizing the contents of the components in the conductive paste, giving full play to the synergistic cooperation among the components, the flexibility, conductivity, or comprehensive performance of the conductive paste can be further improved, and at the same time, the production cost of the conductive paste can be reduced.

[0056] In some embodiments, in the above-mentioned conductive component, the mass ratio of the conductive main component to the conductive stretching component is (30-97):(3-70), for example, it can be 30:70, 40:60, 50:50, 60:40, 70:30, 80:20, 85:15, 90:10, 92:8, 95:5, 97:3, etc., but it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable. Different ratios of the conductive main component to the conductive stretching component will affect the initial resistivity and stretching resistivity of the paste. For example, when the ratio of the conductive main component to the conductive stretching component is too large, the content of the conductive stretching component is relatively low, and the resistivity will change relatively greatly after stretching. Therefore, it is necessary to make the ratio of the conductive main component to the conductive stretching component within a suitable range. By optimizing the ratio of the conductive main component and the conductive stretching component, the conductive performance and stretching performance of the finally obtained conductive paste can meet the requirements of the general conductive electronics industry.

[0057] In some embodiments, the mass ratio of the conductive main component to the conductive stretching component is (50-96):(4-50). In some embodiments, the mass ratio of the conductive main component to the conductive stretching component is (60-90):(10-40). That is, in the above-mentioned conductive component, the proportion of the conductive main component in the overall conductive component is generally 30%-97%, further it can be 30%-95%, further it can be 50%-96%, further it can be 60%-90%, and further it can be 65%-85%.

[0058] According to this embodiment, the conductive component, as the conductive material of the conductive core, includes a conductive main material and an auxiliary stretching conductive material, that is, it includes a conductive main component and a conductive stretching component. Among them, the main function of the conductive main component is to provide basic conductive performance to ensure the conduction of the entire circuit; the main function of the conductive stretching component, that is, the auxiliary stretching conductive material, is to provide conductive performance during the stretching or bending process, and the resistance in the non-stretched state is generally relatively large. In the above-mentioned conductive component, the proportion of the conductive main component in the overall conductive component is generally about 30%-95%. If this proportion is too low, the resistivity of the overall paste cannot be guaranteed. If this proportion is too high, in the stretched state, it cannot maintain a certain flexibility, resulting in circuit interruption. Therefore, it is necessary to make the ratio of the conductive main component to the conductive stretching component within the above-mentioned suitable range.

[0059] According to this embodiment, the conductive main component can be a silver-containing material, a copper-containing material, or a silver-containing material and a copper-containing material. Specifically, in some embodiments, the conductive main component includes at least one of silver powder, copper powder, or silver-coated copper powder. For example, the conductive main component can be silver powder, can be copper powder, can be silver-coated copper powder, can be silver powder and silver-coated copper powder, can be silver powder and copper powder, can be copper powder and silver-coated copper powder, can be silver powder, copper powder, and silver-coated copper powder, etc.

[0060] Optionally, the silver powder includes but is not limited to at least one of spherical silver powder, flake silver powder, rod-shaped silver powder, or wire-shaped silver powder. That is, the morphology of the silver powder includes but is not limited to at least one of spherical, flake, rod-shaped, wire-shaped, etc. For example, the silver powder can be spherical silver powder, can be flake silver powder, can be rod-shaped silver powder, can be wire-shaped silver powder; the morphology of the silver powder can be a single type, or can be a combination of two or more of the above selections, and can be arbitrarily combined when it is a combination. Preferably, the silver powder is spherical silver powder or flake silver powder. In addition, the morphologies of the above copper powder and silver-coated copper powder can also be spherical, flake, rod-shaped, wire-shaped, cluster-shaped, etc.

[0061] Optionally, the silver powder is micron-sized silver powder, the copper powder is micron-sized copper powder, and the silver-coated copper powder is micron-sized silver-coated copper powder. That is, the conductive main component is preferably a micron-sized material; or, in other embodiments, the conductive main component can also be a nano-sized material.

[0062] Specifically, in some embodiments, the conductive main component selects materials such as silver ball powder (spherical silver powder), silver flake powder (flake silver powder), silver-coated copper powder, copper powder, etc. with excellent conductivity. Preferably, the conductive main component includes silver ball powder, and silver flake powder and / or silver-coated copper powder; the silver ball powder, silver flake powder, or silver-coated copper powder are all micron-sized.

[0063] In some embodiments, the conductive stretching component further includes MXene. That is, the conductive stretching component includes one or more of nano-sized or micron-sized metal materials, MXene, carbon materials, or polymer-coated conductive materials. The conductive stretching component of this embodiment requires good conductivity and excellent stretching performance. Among them, the nano-sized or micron-sized metal material is preferably a nano-sized metal material. The MXene material, as a new type of metal carbide or nitride with a two-dimensional sheet-like structure similar to graphene, has excellent conductivity. Preferably, the conductive stretching component includes polymer-coated conductive materials, and nano-sized metal materials and / or carbon materials.

[0064] Specifically, in some embodiments, the nano- or micro-scale metal material includes at least one of silver nano- or micro-materials, copper nano- or micro-materials, silver-coated copper nano- or micro-materials, gold nano- or micro-materials, gold-coated copper nano- or micro-materials, and gold-coated silver nano- or micro-materials. For example, the nano- or micro-scale metal material can be silver nano-material, can be copper nano-material, can be silver-coated copper nano-material, can be gold nano-material, can be gold-coated copper nano-material, can be gold-coated silver nano-material; or can be silver micro-material, can be copper micro-material, can be silver-coated copper micro-material, etc.; the nano- or micro-scale metal material can be of a single type, or can be a combination of two or more of the above choices, and can be arbitrarily combined when combined. Preferably, the nano- or micro-scale metal material is selected from silver nano-material and silver-coated copper nano- or micro-materials. Using silver nano-material or silver-coated copper material can obtain better technical effects, and has a wide source, which helps to improve conductivity and has excellent tensile properties at the same time.

[0065] In some embodiments, the carbon material includes at least one of graphene, graphene oxide, reduced graphene oxide, chemically functionalized graphene, carbon nanotubes or carbon fibers. For example, the carbon material can be graphene, can be graphene oxide, can be reduced graphene oxide, can be chemically functionalized graphene, can be carbon nanotubes, can be carbon fibers, and can also be a combination of any two or more of the above substances, which will not be listed one by one here. Preferably, the carbon material is selected from graphene and carbon nanotubes. Using graphene or carbon nanotubes can obtain better technical effects, and has a wide source and is easy to obtain, which helps to further improve the stretchability and ensure conductivity.

[0066] In addition, in other embodiments, the nano- or micro-scale metal material and the carbon material are not limited to the several types listed above. When meeting the requirements of good electrical conductivity and excellent tensile properties, etc., the nano- or micro-scale metal material and the carbon material can also adopt other types, which will not be described in detail here one by one.

[0067] In some embodiments, the morphology of the nano- or micro-scale metal material includes but is not limited to at least one of sheet-like, linear, rod-like, core-shell-like or cluster-like. For example, the morphology of silver nano-material, copper nano-material or silver-coated copper nano- or micro-material can be sheet-like, can be linear, can be rod-like, can be core-shell-like, can be cluster-like, etc. Preferably, sheet-like or linear silver material, copper material or silver-coated copper material is used.

[0068] It should be understood that the morphology or size of the material may affect the tensile properties. When used as a conductive tensile component, the morphology of the material is preferably sheet-like or linear, while when used as a conductive main component, it can be spherical or sheet-like. For example, when both the conductive main component and the conductive tensile component are made of silver material, the conductive main component can be spherical silver powder, or a component of spherical silver powder and sheet-like silver powder; the conductive tensile component can be large sheet-like silver powder or linear silver powder.

[0069] Optionally, the carbon material can be a micron-scale or nano-scale material.

[0070] In some embodiments, the polymer-coated conductive material is core-shell shaped, with the core layer being the conductive material and the shell layer being the polymer material, that is, the conductive material is coated with the polymer material. Among them, the conductive material is an inorganic conductive material.

[0071] In some embodiments, the conductive material includes at least one of nanosilver wires, silver powder, copper powder, silver-coated copper powder, graphene, or carbon nanotubes. For example, the conductive material can be nanosilver wires, can be silver powder, can be copper powder, can be silver-coated copper powder, can be graphene, can be carbon nanotubes, or can also be a combination of any two or more of the above substances.

[0072] In some embodiments, the polymer material includes at least one of polyethylene glycol (PEG), polylactic acid (PLA), polyvinylpyrrolidone (PVP), polyacrylic acid (PAA), polyvinyl alcohol (PVA), polyethylene oxide (PEO), poly-L-lactide (PLLA), polycaprolactone (PCL), polyacrylonitrile (PAN), or polymethyl methacrylate (PMMA), that is, the polymer material can be any one of the above substances, or can be a combination of any two or more of the above substances. Preferably, the polymer material is selected from PEG, PLA, or PVP.

[0073] In addition, in other embodiments, the above-mentioned conductive materials and polymer materials are not limited to the several types listed above. When meeting the requirements of good conductivity and excellent tensile properties, other types of conductive materials and polymer materials can also be used, which will not be described in detail one by one here.

[0074] Specifically, in some embodiments, the conductive tensile component includes large silver flakes, silver wires, copper wires, silver-coated copper wires, silver-coated copper flakes, carbon nanotubes, graphene, graphene oxide, MXene, polymer-coated conductive materials, etc. with good conductivity and excellent tensile properties. Among them, the conductive material in the polymer-coated conductive material can be selected from nanosilver wires, silver powder, copper powder, silver-coated copper powder, carbon nanotubes, graphene, etc., and the polymer material can be selected from PEG, PLA, or PVP, etc.

[0075] In some embodiments, the number-average molecular weight of the resin is ≥1000. In some embodiments, the number-average molecular weight of the resin is ≥5000. In some embodiments, the number-average molecular weight of the resin is ≥10000.

[0076] In some embodiments, the resin includes at least one of TPU resin, polyester resin, acrylic resin, amino resin, silicone resin, or epoxy resin. For example, the resin can be TPU resin, can be polyester resin, can be acrylic resin, can be amino resin, can be silicone resin, can be epoxy resin, or can also be a composition of any two or more of the above substances. Among them, the epoxy resin can be bisphenol A epoxy resin. In addition, in other embodiments, the epoxy resin can also be bisphenol F epoxy resin, bisphenol S epoxy resin, glycerol epoxy resin, etc.

[0077] According to this embodiment, the resin is the source of flexibility and tensile properties, and at the same time, it is also the source of the printing performance of the slurry. The number-average molecular weight of the resin should not be lower than 1000, otherwise its tensile and viscosity will be greatly affected. At the same time, for the selection of the resin, TPU resin, polyester resin, acrylic resin, amino resin, silicone resin, or epoxy resin, etc. are generally preferred. In this way, the excellent tensile properties of the resin can ensure the tensile properties of the overall slurry.

[0078] In some embodiments, the boiling point of the solvent is ≥100°C. In some embodiments, the boiling point of the solvent is ≥120°C. In some embodiments, the boiling point of the solvent is ≥150°C.

[0079] In some embodiments, the solvent includes at least one of DBE (dibasic acid ester), MDBE (mixed dimethyl dibasic acid ester), ethylene glycol, dimethylformamide, diethylene glycol dimethyl ether, ethylene glycol monomethyl ether, diethylene glycol butyl ether acetate, diethylene glycol butyl ether, octanol, octyl acetate, xylene, terpineol, or isophorone; that is, the solvent can be any one of the above substances, or can be a composition of any two or more of the above substances, which will not be listed one by one here.

[0080] According to this embodiment, the main function of the solvent is for the convenience of printing. The boiling point of the solvent should not be lower than 100°C, otherwise it may affect printing. For the selection of the solvent, commonly used high-boiling solvents are generally preferred, including but not limited to DBE, MDBE, ethylene glycol, dimethylformamide, ethylene glycol monomethyl ether, diethylene glycol dimethyl ether, diethylene glycol butyl ether acetate, diethylene glycol butyl ether, octanol, octyl acetate, terpineol, xylene, isophorone, etc. The selection range of the solvent is relatively large. In actual applications, it can be preferably selected according to different formulations.

[0081] In some embodiments, the additives include, but are not limited to, at least one of a wetting and dispersing agent, an antifoaming agent, a promoter, a tackifier, a surfactant, a coupling agent, a formability regulator, or a curing regulator; that is, the additive can be any one of the above substances, or can be a combination of any two or more of the above substances. The additives can be selected from various conventional additives applicable to conductive pastes, and different types of additives are utilized to play their corresponding functional roles. In addition, in other embodiments, other types of additives can also be adopted, and this embodiment does not limit this.

[0082] According to this embodiment, the selection and range of additives are relatively large, and generally can be optimized according to the performance of the conductive paste. For example, a conductive paste with poor wetting and dispersion needs to add a certain amount of wetting and dispersing agent. Optionally, the wetting and dispersing agent can be BYK-W909 (wetting and dispersing agent for unsaturated polyester resin), BYK-106, etc. A conductive paste with poor defoaming effect needs to add a certain amount of antifoaming agent. Optionally, the antifoaming agent can be BYK-A500, BYK-066, etc. If the adhesion of the paste needs to be improved, some adhesion promoters need to be added. Optionally, the adhesion promoter can be BYK-4511, BYK-C8000, etc. If the viscosity of the paste does not meet the requirements, a certain amount of tackifier needs to be added. Optionally, the tackifier can be dextrin, carboxymethyl cellulose, propylene glycol phthalate, methyl cellulose, sodium starch phosphate, sodium carboxymethyl cellulose, sodium phycate, casein, sodium polyacrylate, polyethylene oxide, polyvinylpyrrolidone, etc. In addition, if the curing ability of the resin in the conductive paste is insufficient, corresponding thermal curing additives or photoinitiators need to be added, such as amino resins, polyisocyanate resins, blocked isocyanate resins, carbodiimide resins, cleavage-type free radical photoinitiators, hydrogen abstraction-type free radical photoinitiators, cationic photoinitiators, etc.

[0083] It should be noted here that the above various additives such as BYK-W909, BYK-106, BYK-A500, BYK-066, etc. are all products known in the prior art and can be obtained through commercial channels. This embodiment does not limit their sources.

[0084] Based on the same inventive concept, in the second aspect of the present application, an embodiment of the present application further provides a preparation method for preparing the above conductive paste. The preparation method of the conductive paste includes:

[0085] Stir and mix the formula amounts of the conductive main component, the conductive stretching component, the resin, the solvent, and the additives to obtain the conductive paste.

[0086] It should be understood that the specific selection and optimized dosage of the conductive main component, conductive stretching component, resin, solvent and additive used in the preparation method of the conductive paste of the present application are the same as those defined in the conductive paste described in the first aspect of the present application. For details, reference can be made to the description in the first aspect above and will not be elaborated here.

[0087] The preparation method of the conductive paste has a simple process. It only needs to mix each component evenly, has high feasibility, mild conditions, is easy to operate, and is suitable for industrial-scale production.

[0088] Based on the same inventive concept, the embodiments of the present application further provide an electronic device, which includes a substrate and a conductive circuit formed on the substrate, and the conductive circuit is prepared from the conductive paste as described above.

[0089] It should be understood that the electronic device includes the conductive paste provided in this embodiment, and thus has at least all the characteristics and advantages of the conductive paste, which will not be elaborated here.

[0090] The electronic device described in the present invention can be various well-known electronic devices in the art. Considering the function of the conductive paste of the present invention, preferably, the electronic device can be a flexible electronic device, such as a chip, a battery cell, etc.

[0091] In some embodiments, the thickness of the substrate is 20 μm to 500 μm. In some embodiments, the thickness of the substrate is 30 μm to 450 μm. In some embodiments, the thickness of the substrate is 50 μm to 300 μm.

[0092] In some embodiments, the substrate is a flexible and stretchable substrate, and the material of the substrate includes at least one of polydimethylsiloxane (PDMS), thermoplastic polyurethane elastomer rubber (TPU), polyethylene terephthalate (PET), polyethylene (PE), silica gel, polyester or acrylate. That is, the substrate can be any one of the above substances, or can be a combination of any two or more of the above substances. Preferably, the substrate is selected from silica gel or TPU, which has a wide source, low cost and good use performance.

[0093] According to this embodiment, there are certain requirements and limitations for the selection of the flexible and stretchable substrate. For example, after the substrate undergoes tensile deformation, it is required that no unevenness, white spots, orange peel, etc. appear on its surface, as this will affect the adhesion of the conductive material on its surface and its functions. Also, there are certain requirements for the thickness of the substrate. Generally, it is best to select a substrate with a thickness in the range of 20 μm to 500 μm. If the substrate is too thin, it will have a certain impact on the formability of the substrate; if the substrate is too thick, it will have an impact on the tensile properties. Therefore, the substrate within the above thickness range can meet the requirements of tensile properties and formability. At the same time, for the selection of the substrate type, materials such as PDMS, silicone, TPU, polyester, PET, acrylate, and PE can be selected. The above several substrates have certain tensile properties and better performance.

[0094] In some embodiments, the method for preparing the conductive circuit includes: printing the conductive paste on the substrate and curing it to obtain the conductive circuit.

[0095] In some embodiments, the curing temperature is 110 - 160 °C and the time is 10 - 30 min. The curing temperature can be, for example, 110 °C, 120 °C, 130 °C, 140 °C, 150 °C, 160 °C, etc., and the time can be 10 min, 15 min, 20 min, 25 min, 30 min, etc.

[0096] Specifically, the preparation method of the above electronic device includes the following steps:

[0097] (1) Cut the flexible stretchable substrate to cut it into a substrate suitable for printing size.

[0098] (2) Print the prepared flexible conductive paste on the substrate by a suitable method to form a conductive circuit; among them, the printing methods include but are not limited to screen printing, spraying, screw extrusion, etc.

[0099] (3) Volatilize the solvent in the conductive paste at a certain temperature so that the conductive paste forms a solid or a high-viscosity liquid state.

[0100] (4) Cure the paste in a high-viscosity liquid state. The curing method can be one or both of thermal curing and light curing. For example, when using thermal curing for curing, the curing temperature can be 110 - 160 °C and the time is 10 - 30 min.

[0101] In the embodiments of the present application, by using the compounding method of the conductive main component and the conductive stretching component, in the case of adding a preferred conductive stretching component, a better flexible conductive silver paste can be obtained. For example, it can still maintain a good resistivity at a stretching rate of 50%, and at the same time can withstand at least the bending test of R3 level.

[0102] In the embodiments of the present application, when adding a conductive material coated with a polymer, that is, an organic-inorganic composite stretchable conductive material, although the initial resistivity is not particularly high, it can minimize the loss of resistivity in the stretched state.

[0103] Compared with the prior art, the technical solutions of the embodiments of the present application can at least achieve the following technical effects: (1) Using a highly efficient conductive material as the main body, that is, using a highly efficient conductive material as the conductive main body component, can reduce the initial resistivity, so that when finally stretched and bent, the resistivity will not be too large. (2) Adopting the method of compounding the conductive main body component and the conductive stretching component, especially compounding a conductive stretching component with high stretching performance, can ensure the resistivity in the stretched state, and there are relatively high requirements for the selection and addition amount of the highly stretchable conductive material. (3) Adding a conductive material coated with a polymer, that is, a highly stretchable conductive material of organic-inorganic composite, the stretching of the organic matter has little effect on the conductive effect of the inorganic matter.

[0104] The following further illustrates the conductive paste, electronic device and its preparation method of the present application with specific examples. Those skilled in the art will understand that only some examples are described in the present invention, and any other suitable specific examples are within the scope of the present invention.

[0105] Example 1

[0106] 1. A conductive paste, comprising the following components in parts by mass:

[0107] 50 parts of a conductive main body component, 20 parts of a conductive stretching component, 10 parts of a resin, 25 parts of a solvent, and 0.8 part of an auxiliary agent.

[0108] Among them, the conductive main body component includes 40 parts of 2μm spherical silver powder and 10 parts of 10μm flaky silver powder;

[0109] The conductive stretching component includes 10 parts of silver nanowires, 5 parts of carbon nanotubes, and 5 parts of PLA-coated silver nanowires; the average length of the silver nanowires is 20μm, the average wire diameter is 20nm, and the average diameter of the carbon nanotubes is 0.4 - 20nm;

[0110] The resin includes 7 parts of bisphenol A epoxy resin and 3 parts of amino resin; the solvent is isophorone; the auxiliary agent is ethyl cellulose.

[0111] 2. An electronic device, comprising a substrate and a conductive circuit formed on the substrate, the conductive circuit is prepared from the above conductive paste; wherein, the thickness of the substrate is 100μm, and the material of the substrate is silica gel.

[0112] The preparation of the electronic device includes: screen-printing the above conductive silver paste on the surface of a 100-μm silica gel substrate and curing it, that is, drying and curing it under the conditions of 150 °C and 15 min.

[0113] Example 2

[0114] Example 2 is basically the same as Example 1, and the same parts will not be described again. The differences are as follows: In the conductive paste of this example,

[0115] The conductive main component includes 45 parts of 2-μm spherical silver powder and 5 parts of 2-μm spherical copper powder; the conductive stretching component includes 5 parts of silver-coated copper sheets, 5 parts of graphene, and 10 parts of PLA-coated silver-coated copper powder.

[0116] The rest are the same as those in Example 1.

[0117] Example 3

[0118] Example 3 is basically the same as Example 1, and the same parts will not be described again. The differences are as follows: The conductive paste of this example includes the following components in parts by mass:

[0119] 35 parts of conductive main component, 35 parts of conductive stretching component, 12 parts of resin, 30 parts of solvent, and 1.0 part of additive.

[0120] Among them, the conductive main component includes 30 parts of 2-μm spherical silver powder and 5 parts of 10-μm flaky silver powder;

[0121] The conductive stretching component includes 10 parts of carbon nanotubes and 25 parts of PLA-coated silver nanowires;

[0122] The resin includes 8 parts of bisphenol A epoxy resin and 4 parts of polyester resin; the solvent includes 20 parts of isophorone and 10 parts of diethylene glycol dimethyl ether; the additive includes 0.5 part of ethyl cellulose and 0.5 part of sodium carboxymethyl cellulose.

[0123] The rest are the same as those in Example 1.

[0124] Example 4

[0125] 1. A conductive paste, including the following components in parts by mass:

[0126] 30 parts of conductive main component, 20 parts of conductive stretching component, 8 parts of resin, 45 parts of solvent, and 1.1 parts of additive.

[0127] Among them, the conductive main component includes 20 parts of 1-μm spherical silver powder and 10 parts of 5-μm silver-coated copper powder;

[0128] The conductive stretching component includes 5 parts of 10-μm graphene, 5 parts of carbon nanotubes, 5 parts of PVP-coated silver nanowires, and 5 parts of silver-coated copper wires; the silver-coated copper wires have an average length of 30 μm and an average wire diameter of 30 nm.

[0129] The resin is TPU resin; the solvent is terpineol; the additives include 1 part of BYK-410 and 0.1 part of KH-550.

[0130] 2. An electronic device, comprising a substrate and a conductive circuit formed on the substrate, the conductive circuit being prepared from the above conductive paste; wherein, the thickness of the substrate is 100 μm, and the material of the substrate is silica gel.

[0131] The preparation of the electronic device includes: screen-printing the above conductive silver paste on the surface of a 100-μm silica gel substrate and curing it, that is, drying and curing it under the conditions of 130 °C for 20 min.

[0132] Example 5

[0133] Example 5 is basically the same as Example 4, and the same parts will not be repeated. The differences are as follows: In the conductive paste of this example,

[0134] The conductive main component includes 15 parts of 10-μm flaky silver powder and 15 parts of 5-μm silver-coated copper powder;

[0135] The conductive stretching component includes 5 parts of 20-μm graphene oxide, 10 parts of PVA-coated silver nanowires, and 5 parts of silver-coated copper wires.

[0136] The rest are the same as in Example 4.

[0137] Example 6

[0138] 1. A conductive paste, comprising the following components in parts by mass:

[0139] 80 parts of conductive main component, 4 parts of conductive stretching component, 4 parts of resin, 12 parts of solvent, and 0.205 parts of additives.

[0140] Among them, the conductive main component includes 60 parts of 5-μm spherical silver powder and 20 parts of 10-μm silver-coated copper powder;

[0141] The conductive stretching component includes 2 parts of PEG-coated silver nanowires and 2 parts of silver-coated copper wires; the silver-coated copper wires have an average length of 30 μm and an average wire diameter of 30 nm;

[0142] The resin is TPU resin; the solvent is ethylene glycol monomethyl ether; the additives include 0.2 part of BYK-941 and 0.05 part of KH-550.

[0143] 2. An electronic device, comprising a substrate and a conductive circuit formed on the substrate, the conductive circuit being prepared from the above conductive paste; wherein, the thickness of the substrate is 150 μm, and the material of the substrate is TPU.

[0144] The preparation of the electronic device includes: screen-printing the above conductive silver paste on the surface of a 150-μm TPU substrate and curing it, that is, drying and curing it under the conditions of 120 °C for 15 minutes.

[0145] Example 7

[0146] Example 7 is basically the same as Example 6, and the same parts will not be described again. The differences are as follows: The conductive paste of this example includes the following components in parts by mass:

[0147] 80 parts of a conductive main component, 20 parts of a conductive stretching component, 6 parts of a resin, 15 parts of a solvent, and 0.205 parts of an auxiliary agent.

[0148] Among them, the conductive stretching component includes 10 parts of PEG-coated silver nanowires and 10 parts of silver-coated copper wires; the average length of the silver-coated copper wires is 30 μm and the average wire diameter is 30 nm;

[0149] The rest are the same as those in Example 6.

[0150] Example 8

[0151] Example 8 is basically the same as Example 6, and the same parts will not be described again. The differences are as follows: The conductive paste of this example includes the following components in parts by mass:

[0152] 20 parts of a conductive main component, 18 parts of a conductive stretching component, 15 parts of a resin, 50 parts of a solvent, and 2 parts of an auxiliary agent.

[0153] Among them, the conductive main component includes 10 parts of 3-μm spherical silver powder and 10 parts of 5-μm silver-coated copper powder;

[0154] The conductive stretching component includes 10 parts of PEG-coated silver nanowires, 5 parts of silver-coated copper wires, and 3 parts of graphene; the average length of the silver-coated copper wires is 20 μm and the average wire diameter is 20 nm;

[0155] The resin includes 8 parts of bisphenol A epoxy resin and 7 parts of TPU resin; the solvent includes 30 parts of ethylene glycol monomethyl ether and 20 parts of dimethylformamide; the auxiliary agent includes 1.0 part of BYK-941, 0.5 part of BYK-C8000, and 0.5 part of carboxymethyl cellulose.

[0156] The rest are the same as those in Example 6.

[0157] Comparative Example 1

[0158] A conductive paste includes the following components in parts by mass:

[0159] 70 parts of conductive main component, 10 parts of resin, 25 parts of solvent, and 0.8 parts of additive.

[0160] Among them, the conductive main component includes 50 parts of 2-μm spherical silver powder and 20 parts of 10-μm flaky silver powder.

[0161] The difference between Comparative Example 1 and Example 1 is that the conductive stretching component in Example 1 is omitted, and the amount of the conductive main component is increased accordingly, and the rest are the same as in Example 1.

[0162] Comparative Example 2

[0163] A conductive paste, comprising the following components in parts by mass:

[0164] 70 parts of conductive stretching component, 10 parts of resin, 25 parts of solvent, and 0.8 parts of additive.

[0165] Among them, the conductive stretching component includes 40 parts of silver nanowires, 15 parts of carbon nanotubes, and 15 parts of PLA-coated silver nanowires; the average length of the silver nanowires is 20 μm and the average wire diameter is 20 nm, and the average length of the carbon nanotubes is 20 μm and the average diameter is 0.4-20 nm.

[0166] The difference between Comparative Example 2 and Example 1 is that the conductive main component in Example 1 is omitted, and the amount of the conductive stretching component is increased accordingly, and the rest are the same as in Example 1.

[0167] Comparative Example 3

[0168] A conductive paste, comprising the following components in parts by mass:

[0169] 5 parts of conductive main component, 15 parts of conductive stretching component, 1.5 parts of resin, 55 parts of solvent, and 0.5 parts of additive.

[0170] Among them, the conductive main component includes 5 parts of 2-μm spherical silver powder, and the conductive stretching component includes 10 parts of silver nanowires and 5 parts of carbon nanotubes.

[0171] The difference between Comparative Example 3 and Example 1 is that the amounts of the conductive main component, the conductive stretching component, and the resin are not within the scope of this application, and the rest are the same as in Example 1.

[0172] Performance test

[0173] In the present invention, the electronic devices containing the conductive paste of Examples 1 to 8 and the electronic devices containing the conductive paste of Comparative Examples 1 to 3 were subjected to performance tests, and the performance test results are shown in Table 1 below.

[0174] The test method includes:

[0175] The initial resistivity of the conductive pastes provided in each example and comparative example was measured using a resistivity tester.

[0176] The electronic device was subjected to a stretching treatment. After stretching by 50% or 100%, the resistivity after stretching by 50% or 100% was then measured using a resistivity tester.

[0177] The electronic device was subjected to a bending treatment. After bending R5 or R4 or R3 10 times, the resistivity after bending 10 times was then measured using a resistivity tester, and the resistance change rate after bending was recorded.

[0178] Table 1

[0179]

[0180]

[0181] Note: "-" in the table indicates that the test for this item was not conducted.

[0182] It can be seen from the data in Table 1 that the conductivity and flexibility of the conductive pastes provided in the examples of the present application are both relatively excellent and can meet the requirements of the general conductive electronics industry. Specifically, the resistivity and tensile properties of the conductive paste of Example 1 are both relatively excellent. Its initial resistivity is 25 μΩ·cm. After stretching by 50%, a resistivity of 50 μΩ·cm can still be measured. At the same time, after bending R5 10 times, the resistance change < 5%. Its tensile and bending properties can fully meet the requirements of the general conductive electronics industry. Compared with Example 1, the silver content of the conductive paste of Example 4 is reduced, which can greatly reduce the cost. At the same time, the resistivity will be affected to a certain extent, but the tensile property of the carbon material is better, and its conductive property in the stretched state is excellent. Its initial resistivity is 50 μΩ·cm. After stretching by 50%, a resistivity of 85 μΩ·cm can still be measured. In the case of stretching by 100%, it can reach 125 μΩ·cm. At the same time, after bending R3 10 times, the resistance change < 5%. Its resistivity and tensile properties can meet the requirements of the general conductive electronics industry. Compared with Example 1, the initial resistivity of the conductive paste of Example 6 is relatively excellent. Its initial resistivity is 15 μΩ·cm. After stretching by 50%, a resistivity of 50 μΩ·cm can still be measured. Although the resistance change rate after stretching is relatively large, due to its excellent initial resistivity, the final resistivity and tensile properties can meet the requirements of the general conductive electronics industry. In addition, Examples 2, 3, 5, 7 - 8 can achieve similar effects to the above Examples 1, 4 or 6, and their resistivity and tensile properties can meet the requirements of the general conductive electronics industry.

[0183] Meanwhile, through the above embodiments, it can be clearly seen that different types and proportions of conductive matrix components, conductive stretching components, and resins will have a certain impact on the initial resistivity and stretching resistivity. Taking three typical embodiments as examples for analysis and illustration, namely Embodiment 1, Embodiment 4, and Embodiment 6; from the comparative analysis between Embodiment 1 and Embodiment 4, it can be known that when 50 parts of conductive matrix components and 20 parts of conductive stretching components are added, the initial resistivity can be as small as 25 μΩ·cm, but the change rate after stretching reaches 100%. In Embodiment 4, when 30 parts of conductive matrix components and 20 parts of conductive stretching components are added, and the content of the flexible resin is higher, the initial resistivity is significantly increased, but the final change rate after stretching reaches 70%, and the material cost is relatively lower. From the comparative analysis between Embodiment 4 and Embodiment 6, it can be known that the change in the stretching resistivity of Embodiment 6 is more obvious. When 80 parts of conductive matrix components and 4 parts of conductive stretching components are added, the change rate after stretching reaches 233%, but its initial resistivity is small, so that the resistance after stretching can still basically meet the requirements.

[0184] Compared with the conductive paste of Embodiment 1 of the present application, the test results of the conductive performance and stretching performance of the conductive pastes of Comparative Examples 1 to 3 are inferior to those of the product of Embodiment 1 and cannot meet the requirements. For example, since the conductive stretching component is not added to the conductive paste of Comparative Example 1, the change rate of the resistance after stretching increases sharply, and the stretching performance cannot meet the requirements; since the conductive matrix component is not added to the conductive paste of Comparative Example 2, the initial resistivity is relatively high, and the conductive performance cannot meet the requirements.

[0185] The parts not detailed in the present invention are well-known technologies to those skilled in the art.

[0186] It should be noted that the term "and / or" or " / " used herein is only a description of the association relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. The singular forms "a", "the", and "said" used in the embodiments of the present invention and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0187] In the specific embodiments and the claims, a list of items connected by the terms "at least one of", "at least a", "at least a kind of" or other similar terms may mean any combination of the listed items. For example, if items A and B are listed, the phrase "at least one of A and B" means only A; only B; or A and B. In another example, if items A, B, and C are listed, the phrase "at least one of A, B, and C" means only A; only B; only C; A and B (excluding C); A and C (excluding B); B and C (excluding A); or all of A, B, and C. Item A may include a single element or multiple elements. Item B may include a single element or multiple elements. Item C may include a single element or multiple elements.

[0188] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A conductive paste, characterized in that, By mass parts, it includes the following components: 50-90 parts of conductive component, 3-15 parts of resin, 10-65 parts of solvent and 0.1-5 parts of auxiliary agent; Among them, the conductive component includes a conductive main component and a conductive stretching component, and the mass ratio of the conductive main component to the conductive stretching component is (30-97):(3-70); The conductive main component includes at least one of micron-sized silver-containing materials or micron-sized copper-containing materials; The conductive stretching component includes a polymer-coated conductive material and a nano-sized metal material, or a polymer-coated conductive material and a carbon material, or a polymer-coated conductive material, a nano-sized metal material and a carbon material, Among them, the polymer-coated conductive material is core-shell shaped, the core layer is a conductive material, and the shell layer is a polymer material. The conductive material includes at least one of silver nanowires, silver powder, copper powder, silver-coated copper powder, graphene or carbon nanotubes, and the polymer material includes at least one of polyethylene glycol, polylactic acid, polyvinylpyrrolidone, polyacrylic acid, polyvinyl alcohol, polyethylene oxide, poly(lactide), polycaprolactone, polyacrylonitrile or polymethyl methacrylate; The nano-sized metal material includes at least one of silver nano materials, copper nano materials, silver-coated copper nano materials, gold nano materials, gold-coated copper nano materials, gold-coated silver nano materials; The carbon material includes at least one of graphene, chemically functionalized graphene, carbon nanotubes or carbon fibers.

2. The conductive paste according to claim 1, wherein By mass parts, it includes the following components: 50-85 parts of conductive component, 4-12 parts of resin, 12-50 parts of solvent and 0.5-2 parts of auxiliary agent; And / or, the mass ratio of the conductive main component to the conductive stretching component is (50-96):(4-50).

3. The conductive paste according to claim 1, wherein At least one of the silver-containing material or copper-containing material includes at least one of silver powder, copper powder or silver-coated copper powder; The silver powder includes at least one of spherical silver powder, flaky silver powder or rod-shaped silver powder.

4. The conductive paste according to claim 1, wherein The conductive stretching component further includes MXene.

5. The conductive paste according to claim 4, wherein, The morphology of the nano-sized metal material includes at least one of flaky, rod-shaped, core-shell shaped or cluster-shaped.

6. The conductive paste according to any one of claims 1 to 5, characterized in that, The number average molecular weight of the resin ≥1000; And / or, the boiling point of the solvent ≥100 °C.

7. The conductive paste according to claim 6, wherein The resin includes at least one of TPU resin, polyester resin, acrylic resin, amino resin, silicone resin or epoxy resin; And / or, the solvent includes at least one of DBE, ethylene glycol, dimethylformamide, diethylene glycol dimethyl ether, ethylene glycol monomethyl ether, diethylene glycol butyl ether acetate, diethylene glycol butyl ether, octanol, octyl acetate, xylene, terpineol or isophorone; And / or, the auxiliary agent includes at least one of a wetting dispersant, a defoaming agent, a promoter, a tackifier, a surfactant or a coupling agent.

8. A method for preparing a conductive paste according to any one of claims 1 to 7, characterized in that, It includes: Stir and mix the formula amounts of the conductive main component, conductive stretching component, resin, solvent and auxiliary agent to obtain a conductive paste.

9. An electronic device, characterized in that, It includes a substrate and a conductive circuit formed on the substrate, and the conductive circuit is prepared from the conductive paste according to any one of claims 1-7.

10. The electronic device according to claim 9, characterized in that, The thickness of the substrate is 20 μm-500 μm; The material of the substrate includes at least one of polydimethylsiloxane, thermoplastic polyurethane elastomer rubber, polyethylene, silica gel or polyester; The method for preparing the conductive circuit includes: printing the conductive paste on the substrate and curing to obtain the conductive circuit; The curing temperature is 110-160°C and the time is 10-30 min.

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