A kind of metal conductive silver paste and its preparation method and application

Abstract

The present invention provides a metal conductive silver paste and a preparation method and application thereof. The metal conductive silver paste of the present invention comprises the following components: a silver conductive paste, a silver source, a reducing agent and a stabilizer; wherein the silver valence in the silver source is zero or +1. The present invention adds a silver source to the traditional silver-coated cheap metal conductive paste, and under the action of the reducing agent, a new silver protective film can be formed on the surface of the cheap metal, thereby ensuring the conductivity of the silver and meeting the requirements of the later aging, solving the problem that the leaked cheap metal cannot be coated, thereby greatly improving the conductivity and aging performance of the paste.

Description

Technical Field

[0001] The present invention relates to the technical field of conductive pastes, and in particular to a metal conductive silver paste and a preparation method and application thereof. Background Art

[0002] With the development of electronic technology, more and more devices have emerged, and more wire connection requirements have been put forward. Lightweight, flexible, high stability, and high conductivity are all future development trends. Silver, as the most frequently used conductive metal in precision circuits at this stage, is frequently used in precision circuit links of various electrical appliances, instruments, and equipment, such as membrane switch silver paste, touch edge silver paste, keyboard silver paste, etc. And with the popularization of these products, the amount of silver used will only increase.

[0003] The existing silver paste, based on the requirements for the resistance performance of different products, most of the silver content will be between 35-70%, and almost all metal powders will use silver powder. Under the premise that the resistance performance meets the requirements, the cost remains high. Most of the time, the international silver price is above 4,000 yuan / kg. The most basic silver paste formula has a material cost of more than 1,500 yuan alone, and even in the high silver content formula, the cost is directly above 3,000 yuan. At the same time, the overall cost of the paste fluctuates. With the large changes in the international silver price, in order to reduce costs, the current mainstream alternative direction is to use silver-coated copper conductive paste to replace silver conductive paste. However, there are two problems with silver-coated copper conductive paste that have not been solved. One is that the silver coating is not complete, copper leakage occurs, affecting the resistance; the other is that in the later aging process, the exposed copper is easily oxidized, thereby generating non-conductive copper oxide substances, affecting the overall conductivity.

[0004] Based on the defects of the current silver conductive paste, it is necessary to improve it. Summary of the invention

[0005] In view of this, the present invention proposes a metal conductive silver paste and a preparation method and application thereof, so as to solve the technical problem that diniconazole is poorly soluble in water in the prior art.

[0006] In a first aspect, the present invention provides a metal conductive silver paste, comprising the following components: a silver conductive paste, a silver source, a reducing agent and a stabilizer;

[0007] The silver valence in the silver source is zero or +1.

[0008] Preferably, in the metallic conductive silver paste, the silver source comprises at least one of nanosilver particles, nanosilver wires, nanosilver clusters, silver oxide, silver nitrate, silver sulfate, silver carbonate, silver acetate, silver lactate, silver bromide, silver iodide, silver phosphate, and silver stearate.

[0009] Preferably, in the metal conductive silver paste, the reducing agent includes at least one of formaldehyde, acetaldehyde, sodium hydroxide, potassium hydroxide, oxalic acid, sodium borohydride, potassium borohydride, copper, iron, polysaccharide, starch, glucose, hydrogen peroxide, ascorbic acid, ethylene glycol, hydrazine hydrate, and 1-methyl-3-butylimidazole tetrafluoroborate.

[0010] Preferably, in the metal conductive silver paste, the stabilizer includes at least one of a mercapto compound, an amino compound, a carboxyl compound, a hydroxyl compound, and a polymer compound.

[0011] Preferably, in the metal conductive silver paste, the stabilizer includes at least one of ethylene glycol, polyethylene glycol, glycerol, thioglycolic acid, mercaptopropionic acid, mercaptobenzoic acid, alkyl mercaptan, thiophene, ammonia, ethylamine, propylenediamine, ethylenediamine, butylamine, long-chain aminoalkanes, formic acid, acetic acid, succinic acid, succinic acid, lactic acid, stearic acid, oleic acid, palmitic acid, carboxyalkanes, polyethylene, polyvinylpyrrolidone, pyrrolidoneacetamide, and dimethylformamide.

[0012] Preferably, the metal conductive silver paste, the silver conductive paste includes at least one of silver-coated copper conductive paste and silver-coated nickel conductive paste.

[0013] Preferably, the metal conductive silver paste, the silver-coated copper conductive paste comprises silver-coated copper powder, resin and solvent;

[0014] And / or, the silver-coated nickel conductive paste comprises silver-coated nickel powder, resin and solvent;

[0015] And / or, the silver-coated iron conductive paste comprises silver-coated iron powder, resin and solvent;

[0016] And / or, the resin includes at least one of epoxy resin, polyester resin and acrylic resin;

[0017] And / or, the solvent includes at least one of DBE, ethylene glycol ethyl ether acetate, ethylene glycol butyl ether acetate, diethylene glycol butyl ether acetate, diethylene glycol ethyl ether acetate, diethylene glycol butyl ether, and terpineol;

[0018] And / or, the mass ratio of the silver-coated copper powder or the silver-coated nickel powder, the resin and the solvent is (30-50):(5-15):(40-60).

[0019] Preferably, in the metal conductive silver paste, the mass of the silver source is 3-15% of the silver conductive paste;

[0020] The mass of the reducing agent is 1-5% of the silver conductive paste;

[0021] The mass of the stabilizer is 0.2-1% of the silver conductive paste.

[0022] In a second aspect, the present invention also provides a method for preparing the metal conductive silver paste, comprising mixing a silver conductive paste, a silver source, a reducing agent and a stabilizer, and stirring the mixture to obtain the metal conductive silver paste.

[0023] In a third aspect, the present invention also provides an application of the metal conductive silver paste in precision circuits.

[0024] The metal conductive silver paste of the present invention has the following beneficial effects compared with the prior art:

[0025] The metal conductive silver paste of the present invention comprises a silver conductive paste, a silver source, a reducing agent and a stabilizer. The present invention adds a silver source to a traditional silver-coated cheap metal conductive paste. Under the action of the reducing agent, a new silver protective film can be formed on the surface of the cheap metal, thereby ensuring the conductivity of the silver and meeting the requirements of later aging, solving the problem that the leaked cheap metal cannot be coated, thereby greatly improving the conductivity and aging performance of the paste. DETAILED DESCRIPTION

[0026] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] The present invention provides a metal conductive silver paste, comprising the following components: silver conductive paste, a silver source, a reducing agent and a stabilizer;

[0028] Among them, the chemical valence of silver in Yinyuan is zero or +1.

[0029] It should be noted that the metal conductive silver paste of the present application includes silver conductive paste, a silver source, a reducing agent and a stabilizer, wherein the silver conductive paste is a traditional silver-coated cheap metal conductive paste, which mainly includes very conventional formula combinations and proportions such as silver powder, silver-coated cheap metal powder, epoxy resin, curing agent, rheological agent, solvent, etc. The silver-coated cheap metal conductive paste is not the focus of the present application and will not be elaborated on in detail here. Specifically, the silver-coated cheap metal conductive paste can be: silver-coated copper conductive paste, silver-coated nickel conductive paste, etc.; the present application adds a silver source, a reducing agent and a stabilizer to the traditional silver-coated cheap metal conductive paste; the silver valence in the silver source is zero or +1; under the action of the reducing agent, the leaked copper / copper oxide on the surface of the traditional silver-coated cheap metal conductive paste (specifically, silver-coated copper conductive paste) will be reduced to a clean copper surface without ligand protection on the surface, and the silver source is also reduced to generate free silver ions at the same time. When encountering the copper surface, a replacement reaction occurs, thereby completely reacting the exposed copper and coating it, thereby avoiding the electrical and aging properties affected by the leaked copper. The existing coating technology makes it difficult to use cheap metals under more stringent aging conditions. Excessive exposure of cheap metal seriously affects the conductivity and later aging of silver. The metal conductive silver paste of the present application, based on the traditional silver-coated cheap metal conductive paste, can more efficiently form a new silver protective film on the surface of the cheap metal by adding a silver source, thereby ensuring the conductivity of silver while meeting the needs of later aging, solving the problem that the leaked cheap metal cannot be coated, thereby greatly improving the conductivity and aging performance of the paste.

[0030] In the metal conductive silver paste of the present application, the role of the silver source is to provide silver material for coating the defects of the silver-coated cheap metal, which can be a zero-valent silver source or a high-valent silver source (i.e., a +1-valent silver source). The reducing agent has two functions. One is to reduce the high-valent cheap metal on the surface of the silver-coated cheap metal, such as copper oxide, cuprous oxide, nickel oxide, etc., and the other is to reduce the high-valent silver source to a low-valent silver source that can conduct electricity efficiently. The role of the stabilizer is to stabilize and disperse the silver source that has not been reduced, because whether it is a low-valent or high-valent silver source, if there is a problem with stability or dispersibility, it will have a huge impact on the conductivity and aging properties of the final slurry.

[0031] In some embodiments, the silver source is the core of the metallic conductive silver paste of the present application, and is the key point of coating the exposed silver-coated cheap metal. It is based on a conventional stable silver source, for example, the silver source includes at least one of nanosilver particles (particle size <5 nm), nanosilver wires (diameter 5-20 nm), nanosilver clusters (particle size <5 nm), nanosilver clusters, silver oxide, silver nitrate, silver sulfate, silver carbonate, silver acetate, silver lactate, silver bromide, silver iodide, silver phosphate, and silver stearate.

[0032] In some embodiments, the reducing agent is used to reduce the oxidized cheap metal on the surface of the silver-coated cheap metal and / or reduce the high-valent silver source, and is generally based on a conventional stable reducing agent; specifically, the reducing agent includes at least one of formaldehyde, acetaldehyde, sodium hydroxide, potassium hydroxide, oxalic acid, sodium borohydride, potassium borohydride, copper, iron, polysaccharides, starch, glucose, hydrogen peroxide, ascorbic acid, ethylene glycol, hydrazine hydrate, and 1-methyl-3-butylimidazole tetrafluoroborate.

[0033] In some embodiments, the stabilizer is used to stabilize and disperse the silver source, including high-valent and low-valent silver sources; the stabilizer includes at least one of thiol compounds, amino compounds, carboxyl compounds, hydroxyl compounds, and polymer compounds. The specific compounds are listed in part below, but the compounds that stabilize silver are too complicated to be listed here one by one; specifically, the stabilizer includes at least one of ethylene glycol, polyethylene glycol, glycerol, thioglycolic acid, thiopropionic acid, mercaptobenzoic acid, alkyl mercaptan, thiophene, ammonia, ethylamine, propylenediamine, ethylenediamine, butylamine, long-chain aminoalkanes, formic acid, acetic acid, succinic acid, succinic acid, lactic acid, stearic acid, oleic acid, palmitic acid, carboxyalkanes, polyethylene, polyvinylpyrrolidone, pyrrolidoneacetamide, and dimethylformamide.

[0034] The metal conductive silver paste, silver source, reducing agent and stabilizer of the present application can make the powder of silver-coated cheap metal be utilized very efficiently, and the exposed cheap metal can be easily coated without affecting the aging performance; in the selection of silver source, two kinds of silver sources, low-valent state and high-valent state, are innovatively proposed, making it easier to deposit on the surface of thermodynamically unstable cheap metal, thereby realizing thermodynamically stable coating.

[0035] In some embodiments, the silver conductive paste includes at least one of a silver-coated copper conductive paste, a silver-coated nickel conductive paste, and a silver-coated iron conductive paste.

[0036] In some embodiments, the silver-coated copper conductive paste includes silver-coated copper powder, resin, and solvent.

[0037] In some embodiments, the silver-coated nickel conductive paste includes silver-coated nickel powder, resin, and solvent.

[0038] In some embodiments, the resin includes at least one of epoxy resin, polyester resin, and acrylic resin.

[0039] In some embodiments, the solvent includes at least one of DBE, ethylene glycol ethyl ether acetate, ethylene glycol butyl ether acetate, diethylene glycol butyl ether acetate, diethylene glycol ethyl ether acetate, diethylene glycol butyl ether, and terpineol.

[0040] In some embodiments, the mass ratio of the silver-coated copper powder, the resin and the solvent is (30-50):(5-15):(40-60).

[0041] In some embodiments, the mass ratio of silver-coated nickel powder, resin and solvent is (30-50):(5-15):(40-60).

[0042] In some embodiments, the mass of the silver source is 3 to 15% of the silver conductive paste;

[0043] In some embodiments, the mass of the reducing agent is 1 to 5% of the silver conductive paste;

[0044] In some embodiments, the mass of the stabilizer is 0.2-1% of the silver conductive paste.

[0045] Specifically, the silver-coated copper powder and silver-coated nickel powder involved in this application are prepared by conventional techniques or purchased directly on the market.

[0046] DBE solvent (named DBE by DuPont) is a mixture of three divalent acid esters, commonly known as nylon acid methyl ester, which is a combination of three good environmental solvents: dimethyl succinate (butanedioic acid) CH3OOC(CH2)2COOCH3, dimethyl glutarate CH3OOC(CH2)3COOCH3 and dimethyl adipate CH3OOC(CH2)4COOCH3.

[0047] Based on the same inventive concept, the embodiment of the present application also provides a method for preparing the above-mentioned metal conductive silver paste, wherein the silver conductive paste, a silver source, a reducing agent and a stabilizer are mixed and stirred to obtain the metal conductive silver paste.

[0048] Based on the same inventive concept, an embodiment of the present application discloses an application of the above-mentioned metal conductive silver paste in precision circuits. Specifically, the metal conductive silver paste of the present application can be applied to precision circuit links of various electrical appliances, instruments, equipment, etc., for example, membrane switch silver paste, touch edge silver paste, keyboard silver paste, etc.

[0049] The following further illustrates the metal conductive silver paste of the present application and its preparation method and application with specific examples. This section further illustrates the content of the present invention in conjunction with specific examples, but should not be construed as limiting the present invention. Unless otherwise specified, the technical means adopted in the embodiments are conventional means well known to those skilled in the art. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art. The polyester resin used in the following examples is Toyobo saturated polyester resin GK-680, and the acrylic resin used is Rohm acrylic resin from Germany.

[0050] Example 1

[0051] The embodiment of the present application provides a metal conductive silver paste, comprising the following components: silver conductive paste, a silver source, a reducing agent and a stabilizer;

[0052] The silver conductive paste comprises: 40 parts by weight of silver-coated copper powder (the mass fraction of silver in the silver-coated copper powder is 20%), 5 parts by weight of polyester resin, 5 parts of acrylic resin, and 50 parts of DBE solvent;

[0053] The silver source is nanosilver clusters (average particle size is 3nm), the reducing agent is ethylene glycol, the stabilizer is succinic acid, the mass of the nanosilver clusters is 10% of the mass of the silver conductive paste, the amount of ethylene glycol is 2% of the mass of the silver conductive paste, and the mass of succinic acid is 0.8% of the mass of the silver conductive paste.

[0054] The preparation method of the above-mentioned metal conductive silver paste is: after mixing the silver conductive paste, the silver source, the reducing agent and the stabilizer, stirring evenly, the metal conductive silver paste is obtained.

[0055] Example 2

[0056] The embodiment of the present application provides a metal conductive silver paste, which uses high-valent silver as the silver source compared to the embodiment 1, and adds a larger amount of silver source and a reducing agent with stronger reducing property, and specifically includes the following components: silver conductive paste, silver source, reducing agent and stabilizer;

[0057] The silver conductive paste comprises: 40 parts by weight of silver-coated copper powder (the mass fraction of silver in the silver-coated copper powder is 20%), 5 parts by weight of polyester resin, 5 parts of acrylic resin, and 50 parts of DBE solvent;

[0058] The silver source is silver oxide, the reducing agent is acetaldehyde, the stabilizer is polyvinyl pyrrolidone, the mass of silver oxide is 15% of the mass of the silver conductive paste, the mass of acetaldehyde is 5% of the mass of the silver conductive paste, and the mass of polyvinyl pyrrolidone is 1% of the mass of the silver conductive paste.

[0059] The preparation method of the above-mentioned metal conductive silver paste is: after mixing the silver conductive paste, the silver source, the reducing agent and the stabilizer, stirring evenly, the metal conductive silver paste is obtained.

[0060] Example 3

[0061] The embodiment of the present application provides a metal conductive silver paste. Compared with embodiment 1, the silver source adopts a mixed silver source, and a silver source with better stability is selected, and the use of a stabilizer is reduced; specifically, the following components are included: a silver conductive paste, a silver source, a reducing agent, and a stabilizer;

[0062] The silver conductive paste comprises: 40 parts by weight of silver-coated copper powder (the mass fraction of silver in the silver-coated copper powder is 20%), 5 parts by weight of polyester resin, 5 parts of acrylic resin, and 50 parts of DBE solvent;

[0063] The silver source is a mixture of nanosilver wires (with an average diameter of 15 nm) and silver lactate; the reducing agent is ethylene glycol, and the stabilizer is palmitic acid; the mass of the nanosilver wires is 5% of the mass of the silver conductive paste, the mass of the silver lactate is 5% of the mass of the silver conductive paste, the mass of the ethylene glycol is 2% of the mass of the silver conductive paste, and the mass of the palmitic acid is 0.4% of the mass of the silver conductive paste.

[0064] The preparation method of the above-mentioned metal conductive silver paste is: after mixing the silver conductive paste, the silver source, the reducing agent and the stabilizer, stirring evenly, the metal conductive silver paste is obtained.

[0065] Example 4

[0066] The embodiment of the present application provides a metal conductive silver paste. Compared with embodiment 1, the silver source adopts a mixed silver source, a reducing agent with lower reducing property is selected, and a stabilizer with lower stability is selected; the paste specifically comprises the following components: a silver conductive paste, a silver source, a reducing agent and a stabilizer;

[0067] The silver conductive paste comprises: 40 parts by weight of silver-coated copper powder (the mass fraction of silver in the silver-coated copper powder is 20%), 5 parts by weight of polyester resin, 5 parts of acrylic resin, and 50 parts of DBE solvent;

[0068] The silver source is a mixture of nanosilver particles (with an average particle size of 3 nm) and silver stearate; the reducing agent is ascorbic acid, and the stabilizer is dimethylformamide; the mass of the nanosilver particles is 3% of the mass of the silver conductive paste, the mass of the silver stearate is 4% of the mass of the silver conductive paste, the mass of the ascorbic acid is 1.5% of the mass of the silver conductive paste, and the mass of the dimethylformamide is 0.6% of the mass of the silver conductive paste.

[0069] The preparation method of the above-mentioned metal conductive silver paste is: after mixing the silver conductive paste, the silver source, the reducing agent and the stabilizer, stirring evenly, the metal conductive silver paste is obtained.

[0070] Example 5

[0071] The present application embodiment provides a metal conductive silver paste. Compared with embodiment 1, the silver source adopts silver-coated nickel powder; specifically, the paste comprises the following components: silver conductive paste, silver source, reducing agent and stabilizer;

[0072] The silver conductive paste comprises: 40 parts by weight of silver-coated nickel powder (the mass fraction of silver in the silver-coated nickel powder is 20%), 5 parts by weight of polyester resin, 5 parts of acrylic resin, and 50 parts of DBE solvent;

[0073] The silver source is nanosilver clusters (average particle size is 3nm), the reducing agent is ethylene glycol, the stabilizer is succinic acid, the mass of the nanosilver clusters is 10% of the mass of the silver conductive paste, the amount of ethylene glycol is 2% of the mass of the silver conductive paste, and the mass of succinic acid is 0.8% of the mass of the silver conductive paste.

[0074] The preparation method of the above-mentioned metal conductive silver paste is: after mixing the silver conductive paste, the silver source, the reducing agent and the stabilizer, stirring evenly, the metal conductive silver paste is obtained.

[0075] Comparative Example 1

[0076] This embodiment provides a conductive silver paste, which does not add a silver source, a reducing agent and a stabilizer compared to Example 1; it specifically includes the following components: 40 parts by weight of silver-coated nickel powder (the mass fraction of silver in the silver-coated nickel powder is 20%), 5 parts by weight of polyester resin, 5 parts of acrylic resin, and 50 parts of DBE solvent.

[0077] The preparation method of the conductive silver paste is as follows: silver-coated nickel powder, polyester resin, acrylic resin and DBE solvent are mixed and stirred evenly to obtain the conductive silver paste.

[0078] Comparative Example 2

[0079] This embodiment provides a conductive silver paste, which only adds a silver source, and does not add a reducing agent and a stabilizer, compared with Example 1; specifically, it includes the following components: a silver conductive paste and a silver source;

[0080] The silver conductive paste comprises: 40 parts by weight of silver-coated copper powder (the mass fraction of silver in the silver-coated copper powder is 20%), 5 parts by weight of polyester resin, 5 parts of acrylic resin, and 50 parts of DBE solvent;

[0081] The silver source is nano silver clusters (average particle size is 3 nm), and the mass of the nano silver clusters is 10% of the mass of the silver conductive paste.

[0082] The preparation method of the metal conductive silver paste is as follows: silver conductive paste and a silver source are mixed and stirred evenly to obtain the metal conductive silver paste.

[0083] Comparative Example 3

[0084] This embodiment provides a conductive silver paste, which only adds a silver source and a reducing agent, and does not add a stabilizer, compared with Example 1; specifically, it includes the following components: a silver conductive paste, a silver source, and a reducing agent;

[0085] The silver conductive paste comprises: 40 parts by weight of silver-coated copper powder (the mass fraction of silver in the silver-coated copper powder is 20%), 5 parts by weight of polyester resin, 5 parts of acrylic resin, and 50 parts of DBE solvent;

[0086] The silver source is nano silver clusters (average particle size is 3 nm), the reducing agent is ethylene glycol, the mass of the nano silver clusters is 10% of the mass of the silver conductive paste, and the amount of ethylene glycol is 2% of the mass of the silver conductive paste.

[0087] The preparation method of the above-mentioned metal conductive silver paste is: after mixing the silver conductive paste, the silver source and the reducing agent, stirring evenly, the metal conductive silver paste is obtained.

[0088] Performance Testing

[0089] The metal conductive silver paste obtained in Examples 1 to 5 and the conductive silver paste obtained in Comparative Examples 1 to 3 were stirred and mixed by a disperser to a fineness of <15 μm, coated on a substrate and cured at 150° C. for 30 min, and the resistivity was tested; then aged for 240 h at 85° C. and 85% RH (i.e., relative humidity 85%) and the resistivity was tested again. The results are shown in Table 1.

[0090] Table 1 - Resistivity of conductive silver paste after curing and aging in different embodiments

[0091]

[0092]

[0093] As can be seen from Table 1, in Example 1, by adding a silver source, a reducing agent and a stabilizer, the metal conductive silver paste can protect almost all the exposed copper after curing, and there is no risk of copper exposure during the continuous aging process, and the resistivity remains unchanged after aging; Compared with Examples 1 to 2, in Example 2, after adding more silver sources and strong reducing agents, the metal conductive silver paste has a lower resistance, and the surface of the silver-coated copper powder is more densely wrapped. At the same time, during the aging process, the silver is further reduced, further reducing the resistance; Compared with Examples 1 and 3, a more stable silver source is selected, and it is the case of nano silver wires. Under the condition of aging, more silver-coated copper powder is overlapped and protected, and during the aging process, due to the stability of the silver source, the resistivity can be further reduced; Comparing Examples 1 and 4, by adding a small amount of high-efficiency silver source and a more matching reducing agent and stabilizer, efficient silver-coated copper surface coating can be achieved, and the resistivity is reduced more significantly after aging, indicating that more silver sources are effectively deposited on the copper surface rather than the silver surface; Comparing Examples 1 and 5, the effect of coating different cheap metal powders is still good. Since the resistivity of nickel is greater than that of copper, the initial resistivity will have a certain loss, but the effect remains unchanged after aging.

[0094] In Comparative Example 1, no silver source or protective measures are added, and the exposed copper will be completely oxidized during aging, which greatly affects the overall conductive performance. It can be seen from Comparative Example 2 that only adding a silver source can also improve the conductive efficiency to a certain extent, but due to the absence of a reducing agent and a stabilizer, more silver is simply present and not covered on the copper surface, so that most of the conductive performance will still be lost during the aging process. It can be seen from Comparative Example 3 that silver can still be efficiently reduced without adding a stabilizer. Similarly, due to insufficient stability, more silver is kinetically reduced to the silver surface instead of copper, which greatly reduces the aging performance.

[0095] The above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A metallic conductive silver paste, characterized in that: The invention comprises the following components: silver conductive paste, silver source, reducing agent and stabilizing agent; Wherein, the silver valence in the silver source is zero or +1; The silver source is a mixture of nano silver wires and silver lactate; Or, the silver source is a mixture of nanosilver particles and silver stearate; The reducing agent is any one of ethylene glycol and ascorbic acid; the stabilizing agent is any one of palmitic acid and dimethylformamide; The silver conductive paste is a silver-coated copper conductive paste; The silver-coated copper conductive paste comprises silver-coated copper powder, resin and solvent; The resin includes at least one of epoxy resin, polyester resin and acrylic resin; The solvent includes at least one of DBE, ethylene glycol ethyl ether acetate, ethylene glycol butyl ether acetate, diethylene glycol butyl ether acetate, diethylene glycol ethyl ether acetate, diethylene glycol butyl ether, and terpineol; The mass ratio of the silver-coated copper powder, the resin and the solvent is (30-50):(5-15):(40-60); The mass of the silver source is 3-15% of the silver conductive paste; The mass of the reducing agent is 1-5% of the silver conductive paste; The mass of the stabilizer is 0.2-1% of the silver conductive paste.

2. A method for preparing the metallic conductive silver paste as claimed in claim 1, characterized in that: The silver conductive paste, the silver source, the reducing agent and the stabilizer are mixed and stirred to obtain the metallic conductive silver paste.

3. An application of the metal conductive silver paste as claimed in claim 1 in precision circuits.

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