High conductivity, high stability, low temperature curing silver paste for inductor and preparation method thereof

Abstract

The present invention relates to the technical field of conductive materials, and specifically discloses a high-conductivity, high-stability, low-temperature curing silver paste for inductors and a preparation method thereof. The high-conductivity, high-stability, low-temperature curing silver paste for inductors comprises the following components in parts by mass: 50-70 parts of spherical silver powder; 10-30 parts of flaky silver powder; 20-21 parts of epoxy resin carrier; 1-3 parts of curing agent; 0.1-1 parts of curing accelerator; 0.1-1 parts of auxiliary agent; the epoxy resin carrier is prepared by dissolving epoxy resin in an organic solvent; the epoxy resin is a compound of epoxy resin A, epoxy resin B, and epoxy resin C; the curing agent is a compound of phenolic resin A and phenolic resin B. The present invention has the advantages of making the low-temperature curing silver paste have both high conductivity and high stability.

Description

Technical Field

[0001] The invention relates to the field of conductive materials, and in particular to a high-conductivity, high-stability, low-temperature curing silver paste for inductance and a preparation method thereof. Background Art

[0002] With the rapid development of the electronic information industry, low-temperature curing silver paste is widely used in membrane switches, touch screens, capacitor electrodes, printed circuits, solar cells, etc., because it can significantly reduce the curing temperature. As electronic products develop towards more powerful functionality and more environmentally friendly directions, higher requirements are also placed on their performance.

[0003] Low-temperature curing conductive silver paste is mainly composed of silver powder, resin bonding phase, solvent and other additives. The conductive functional phase silver powder is the most important part of the silver paste. It plays the role of conducting electrons and determines the conductive properties of the low-temperature curing silver paste. After the silver paste is cured, the resin forms a cross-linked network that will cover the silver powder particles, so that the silver powder particles are separated from each other, which increases the resistance of the conductive layer. Therefore, in order to obtain higher conductivity, it is usually necessary to increase the silver content, but this may lead to increased costs. In order to achieve low-temperature curing, it may be necessary to select specific resins and solvents, but this may affect the conductive properties of the silver paste. Therefore, it is often difficult to achieve both high conductivity and stability in the preparation process of existing silver paste materials, which to a certain extent limits its use in certain specific application scenarios. Therefore, there is still room for improvement. Summary of the invention

[0004] In order to make the low-temperature curing silver paste have both high conductivity and high stability, the present application provides a high-conductivity and high-stability low-temperature curing silver paste for inductance and a preparation method thereof.

[0005] In the first aspect, the present application provides a high conductivity, high stability, low temperature curing silver paste for inductance, which adopts the following technical solution:

[0006] A high conductivity, high stability and low temperature curing silver paste for inductance, comprising the following components in parts by mass:

[0007] 50-70 parts of spherical silver powder;

[0008] 10-30 parts of flaky silver powder;

[0009] Epoxy resin carrier 20-21 parts;

[0010] 1-3 parts of curing agent;

[0011] Curing accelerator 0.1-1 part;

[0012] Additives 0.1-1 part;

[0013] The epoxy resin carrier is prepared by dissolving epoxy resin in an organic solvent;

[0014] The epoxy resin is a compound of epoxy resin A, epoxy resin B and epoxy resin C;

[0015] The curing agent is a compound of phenolic resin A and phenolic resin B.

[0016] By adopting the above technical solution, the contact area between the silver powder particles is increased through the combination of spherical silver powder and flaky silver powder, which can effectively reduce the resistance. At the same time, the dispersibility of the silver powder and the rheological properties of the slurry are guaranteed, so that it can adapt to different capping and printing processes.

[0017] By combining epoxy resin A, epoxy resin B, epoxy resin C with phenolic resin A and phenolic resin B, a special dense network structure is formed, which has higher thermal stability. The special dense network structure helps to reduce moisture penetration, improve the stability of electronic products in humid and high temperature environments, and make the long-term storage stability of silver paste higher.

[0018] As a result, the high conductivity, high stability and low temperature curing silver paste used in inductors has both high conductivity and high stability.

[0019] Preferably, the spherical silver powder has a D50 of 3.0-5.0 microns and a tap density of 4.5-6.0 g / cm 3 .

[0020] Preferably, the D50 of the flaky silver powder is 1.0-2.0 microns and the tap density is 4.0-5.0 g / cm 3 .

[0021] By adopting the above technical solution, the contact area between the silver powder particles is better increased, and the resistance can be more effectively reduced.

[0022] Preferably, in the epoxy resin carrier, the mass ratio of epoxy resin to organic solvent is 40-60:40-60.

[0023] By adopting the above technical solution and specifically selecting the mass ratio of epoxy resin and organic solvent, the fluidity of the epoxy resin carrier is better, the dispersibility of the silver powder is better, and the product quality is better.

[0024] Preferably, the mass ratio of the epoxy resin A, epoxy resin B and epoxy resin C is 10-18:15-21:15-21.

[0025] By adopting the above technical solution and specifically selecting the mass ratio of epoxy resin A, epoxy resin B, and epoxy resin C, a special dense network structure can be better formed, so that the resistance of the silver paste is lower, the stability of long-term storage is higher, and the stability after curing is better.

[0026] Preferably, the mass ratio of the phenolic resin A to the phenolic resin B is 0.4-1.4:0.6-1.6.

[0027] By adopting the above technical scheme and specifically selecting the mass ratio of phenolic resin A and phenolic resin B, the effect of combining with epoxy resin A, epoxy resin B and epoxy resin C is better, and a special dense network structure is better formed, thereby better reducing the resistance of the silver paste, having higher stability in long-term storage, and having better quality of the cured product.

[0028] Preferably, the organic solvent is one or more of butanol, diethylene glycol ethyl ether, diethylene glycol ethyl ether acetate, diethylene glycol butyl ether, diethylene glycol butyl ether acetate, terpineol, and ethylene glycol ethyl ether.

[0029] By adopting the above technical solution, the solubility of the organic solvent is increased, so that the epoxy resin can be well dissolved in the organic solvent to be evenly dispersed, thereby better forming a special dense network structure during curing, which is more conducive to reducing the resistance of the silver paste and improving the stability.

[0030] Preferably, the curing accelerator is an amine curing accelerator.

[0031] By adopting the above technical solution, the curing rate can be greatly improved and the curing temperature can be reduced.

[0032] Preferably, the auxiliary agent is one or more of thixotropic agents such as fumed silica, polyamide wax, and hydrogenated castor oil.

[0033] By adopting the above technical solution, the viscosity and thixotropy of the slurry can be effectively improved, so that the silver powder is dispersed more evenly and the quality of the silver paste is higher.

[0034] In a second aspect, the present application provides a method for preparing a high-conductivity, high-stability, low-temperature curing silver paste for inductors, using the following technical solution:

[0035] A method for preparing the above-mentioned high conductivity, high stability and low temperature curing silver paste for inductance is characterized by comprising the following steps:

[0036] Step 1), mixing the epoxy resin carrier, curing agent, curing accelerator and auxiliary agent to obtain a resin solution;

[0037] Step 2), spherical silver powder and flaky silver powder are added into the resin solution, mixed evenly, and ground to obtain a high conductivity, high stability, and low temperature curing silver paste for inductance.

[0038] By adopting the above technical solution, the low-temperature curing silver paste obtained has high conductivity and high stability, and the long-term storage stability is also high, and has broad application prospects.

[0039] In summary, this application has the following beneficial effects:

[0040] 1. Since the present application increases the contact area between silver powder particles by combining spherical silver powder with flaky silver powder, the resistance can be effectively reduced, while ensuring the dispersibility of silver powder and the rheological properties of the slurry, so that it can adapt to different capping and printing processes. By combining epoxy resin A, epoxy resin B, epoxy resin C with phenolic resin A and phenolic resin B, a special dense network structure is formed with higher thermal stability. The special dense network structure helps to reduce the penetration of moisture and improve the stability of electronic products in humid and high temperature environments. It also makes the long-term storage stability of the silver paste higher, so that the high conductivity, high stability and low temperature curing silver paste used in the inductor has both high conductivity and high stability.

[0041] 2. In the present application, it is preferred to form a special dense network structure by specifically selecting the mass ratio of epoxy resin A, epoxy resin B, and epoxy resin C, so that the resistance of the silver paste is lower, the stability of long-term storage is higher, and the stability after curing is better.

[0042] 3. In the present application, it is preferred to specifically select the mass ratio of phenolic resin A and phenolic resin B, and the effect of cooperating with epoxy resin A, epoxy resin B and epoxy resin C is better, so as to better form a special dense network structure, thereby better reducing the resistance of the silver paste, having higher stability in long-term storage, and having better quality of the product after curing. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 The magnifying glass pictures are of the front and end faces of the inductor after the termination and curing in each embodiment and comparative example. DETAILED DESCRIPTION

[0044] The present application is further described in detail below with reference to the embodiments.

[0045] Example 1

[0046] A high conductivity, high stability, low temperature curing silver paste for inductors, comprising the following components:

[0047] Spherical silver powder, flake silver powder, epoxy resin carrier, curing agent, curing accelerator, additives.

[0048] Spherical silver powder is commercially available with a particle size of 3-5 μm and a tap density of 4.5-6.0 g / cm 3 .

[0049] The flaky silver powder is commercially available with a particle size of 1-2 μm and a tap density of 4.0-5.0 g / cm 3 .

[0050] The epoxy resin carrier is prepared by dissolving epoxy resin in an organic solvent.

[0051] The epoxy resin is a compound of epoxy resin A, epoxy resin B and epoxy resin C.

[0052] The organic solvent is a compound of butanol, diethylene glycol ethyl ether and diethylene glycol ethyl ether acetate.

[0053] The preparation method of the epoxy resin carrier is as follows:

[0054] Step 01), butanol, diethylene glycol ethyl ether, and dioxalic acid ethyl ether acetate are mixed in a mass ratio of 1:1:1 to form an organic solvent.

[0055] Step 02), take 60g of organic solvent, 10g of epoxy resin A, 15g of epoxy resin B, and 15g of epoxy resin C and put them into a stirring kettle, rotate at 800r / min, stir for 90min, and obtain an epoxy resin carrier.

[0056] Butanol is commercially available, CAS number: 35296-72-1.

[0057] Diethylene glycol ethyl ether is commercially available, CAS number: 111-90-0.

[0058] Diethyl ether acetate is commercially available, CAS number: 112-15-2.

[0059] Epoxy resin A is bisphenol A type epoxy resin, which comes from Kunshan Nanya Epoxy Resin Company, brand: NPES-901.

[0060] Epoxy resin B is bisphenol A epoxy resin, which comes from Guodu Chemical (Kunshan) Co., Ltd., brand: YD-017H.

[0061] Epoxy resin C is bisphenol F type epoxy resin, which comes from Guodu Chemical (Kunshan) Co., Ltd., brand: YDF-2001.

[0062] The curing agent is a compound of phenolic resin A and phenolic resin B.

[0063] Phenolic resin A is bisphenol A phenolic resin, which comes from Jinan Shengquan Group Co., Ltd.

[0064] Phenolic resin B is o-cresol-formaldehyde resin, which comes from Suzhou Senfida Chemical Co., Ltd.

[0065] The curing accelerator is an amine curing accelerator, which comes from Jinan Xinyu New Materials Co., Ltd., model: t31-2.

[0066] The additive is fumed silica, from Evonik, model: A200.

[0067] The preparation method of high conductivity, high stability and low temperature curing silver paste for inductors is as follows:

[0068] Step 1), 20g epoxy resin carrier, 0.4g phenolic resin A, 0.6g phenolic resin B, 0.1g curing accelerator, 0.1g auxiliary agent are put into a stirring kettle, the speed is 120r / min, stirring for 10min, mixing evenly, to obtain a resin solution.

[0069] Step 2), 50g of spherical silver powder and 10g of flaky silver powder are put into the resin solution, the speed is 120r / min, stirred for 10min, mixed evenly, and finally ground with a three-roll mill to less than 10.0μm to obtain a high conductivity, high stability and low temperature curing silver paste for inductor.

[0070] Example 2

[0071] A high conductivity, high stability, low temperature curing silver paste for inductors, comprising the following components:

[0072] Spherical silver powder, flake silver powder, epoxy resin carrier, curing agent, curing accelerator, additives.

[0073] Spherical silver powder is commercially available with a particle size of 3-5 μm and a tap density of 4.5-6.0 g / cm 3 .

[0074] The flaky silver powder is commercially available with a particle size of 1-2 μm and a tap density of 4.0-5.0 g / cm 3 .

[0075] The epoxy resin carrier is prepared by dissolving epoxy resin in an organic solvent.

[0076] The epoxy resin is a compound of epoxy resin A, epoxy resin B and epoxy resin C.

[0077] The organic solvent is a compound of butanol, diethylene glycol ethyl ether and diethylene glycol ethyl ether acetate.

[0078] The preparation method of the epoxy resin carrier is as follows:

[0079] Step 01), butanol, diethylene glycol ethyl ether, and dioxalic acid ethyl ether acetate are mixed in a mass ratio of 1:1:1 to form an organic solvent.

[0080] Step 02), take 50g of organic solvent, 14g of epoxy resin A, 18g of epoxy resin B, and 18g of epoxy resin C and put them into a stirring kettle, rotate at 900r / min, stir for 105min, and obtain an epoxy resin carrier.

[0081] Butanol is commercially available, CAS number: 35296-72-1.

[0082] Diethylene glycol ethyl ether is commercially available, CAS number: 111-90-0.

[0083] Diethyl ether acetate is commercially available, CAS number: 112-15-2.

[0084] Epoxy resin A is bisphenol A type epoxy resin, which comes from Kunshan Nanya Epoxy Resin Company, brand: NPES-901.

[0085] Epoxy resin B is bisphenol A epoxy resin, which comes from Guodu Chemical (Kunshan) Co., Ltd., brand: YD-017H.

[0086] Epoxy resin C is bisphenol F type epoxy resin, which comes from Guodu Chemical (Kunshan) Co., Ltd., brand: YDF-2001.

[0087] The curing agent is a compound of phenolic resin A and phenolic resin B.

[0088] Phenolic resin A is bisphenol A phenolic resin, which comes from Jinan Shengquan Group Co., Ltd.

[0089] Phenolic resin B is o-cresol-formaldehyde resin, which comes from Suzhou Senfida Chemical Co., Ltd.

[0090] The curing accelerator is an amine curing accelerator, which comes from Tonglan New Energy Technology Development (Shandong) Group Co., Ltd., product name: DMP-30.

[0091] The additive is fumed silica, from Evonik, model: A200.

[0092] The preparation method of high conductivity, high stability and low temperature curing silver paste for inductors is as follows:

[0093] Step 1), 20.5g epoxy resin carrier, 0.9g phenolic resin A, 1.1g phenolic resin B, 0.5g curing accelerator, 0.5g auxiliary agent are put into a stirring kettle, the speed is 120r / min, stirring for 10min, mixing evenly, to obtain a resin solution.

[0094] Step 2), 60g of spherical silver powder and 20g of flaky silver powder are put into the resin solution, the speed is 120r / min, stirred for 10min, mixed evenly, and finally ground with a three-roll mill to less than 10.0μm to obtain a high conductivity, high stability and low temperature curing silver paste for inductance.

[0095] Example 3

[0096] A high conductivity, high stability, low temperature curing silver paste for inductors, comprising the following components:

[0097] Spherical silver powder, flake silver powder, epoxy resin carrier, curing agent, curing accelerator, additives.

[0098] Spherical silver powder is commercially available with a particle size of 3-5 μm and a tap density of 4.5-6.0 g / cm 3 .

[0099] The flaky silver powder is commercially available with a particle size of 1-2 μm and a tap density of 4.0-5.0 g / cm 3 .

[0100] The epoxy resin carrier is prepared by dissolving epoxy resin in an organic solvent.

[0101] The epoxy resin is a compound of epoxy resin A, epoxy resin B and epoxy resin C.

[0102] The organic solvent is a compound of butanol, diethylene glycol ethyl ether and diethylene glycol ethyl ether acetate.

[0103] The preparation method of the epoxy resin carrier is as follows:

[0104] Step 01), butanol, diethylene glycol ethyl ether, and dioxalic acid ethyl ether acetate are mixed in a mass ratio of 1:1:1 to form an organic solvent.

[0105] Step 02), take 40g organic solvent, 18g epoxy resin A, 21g epoxy resin B, and 21g epoxy resin C and put them into a stirring tank, 1000r / min, stir for 120min, and obtain an epoxy resin carrier.

[0106] Butanol is commercially available, CAS number: 35296-72-1.

[0107] Diethylene glycol ethyl ether is commercially available, CAS number: 111-90-0.

[0108] Diethyl ether acetate is commercially available, CAS number: 112-15-2.

[0109] Epoxy resin A is bisphenol A type epoxy resin, which comes from Kunshan Nanya Epoxy Resin Company, brand: NPES-901.

[0110] Epoxy resin B is bisphenol A epoxy resin, which comes from Guodu Chemical (Kunshan) Co., Ltd., brand: YD-017H.

[0111] Epoxy resin C is bisphenol F type epoxy resin, which comes from Guodu Chemical (Kunshan) Co., Ltd., brand: YDF-2001.

[0112] The curing agent is a compound of phenolic resin A and phenolic resin B.

[0113] Phenolic resin A is bisphenol A phenolic resin, which comes from Jinan Shengquan Group Co., Ltd.

[0114] Phenolic resin B is o-cresol-formaldehyde resin, which comes from Suzhou Senfida Chemical Co., Ltd.

[0115] The curing accelerator is an amine curing accelerator, which comes from Jinan Xinyu New Materials Co., Ltd., model: t31-2.

[0116] The additive is fumed silica, from Evonik, model: A200.

[0117] The preparation method of high conductivity, high stability and low temperature curing silver paste for inductors is as follows:

[0118] Step 1), 21g epoxy resin carrier, 1.4g phenolic resin A, 1.6g phenolic resin B, 1g curing accelerator, 1g auxiliary agent are put into a stirring kettle, the speed is 120r / min, stirring for 10min, mixing evenly, to obtain a resin solution.

[0119] Step 2), 70g of spherical silver powder and 30g of flaky silver powder are put into the resin solution, the speed is 120r / min, stirred for 10min, mixed evenly, and finally ground with a three-roll mill to less than 10.0μm to obtain a high conductivity, high stability and low temperature curing silver paste for inductor.

[0120] Comparative Example 1

[0121] A high conductivity, high stability and low temperature curing silver paste for inductance, compared with Example 2, the only difference is:

[0122] In the epoxy resin carrier, epoxy resin D is used to replace epoxy resin A in equal amounts.

[0123] Epoxy resin D is bisphenol A epoxy resin, which comes from Kunshan Nanya Epoxy Resin Company, brand: NPES-901H.

[0124] Comparative Example 2

[0125] A high conductivity, high stability and low temperature curing silver paste for inductance, compared with Example 2, the only difference is:

[0126] In the epoxy resin carrier, epoxy resin E is used to replace epoxy resin B in equal amounts.

[0127] Epoxy resin E is bisphenol A epoxy resin, sourced from Guodu Chemical (Kunshan) Co., Ltd., brand: YD-019 *4 .

[0128] Comparative Example 3

[0129] A high conductivity, high stability and low temperature curing silver paste for inductance, compared with Example 2, the only difference is:

[0130] In the epoxy resin carrier, epoxy resin F was used to replace epoxy resin C in equal amounts.

[0131] Epoxy resin F is bisphenol F type epoxy resin, sourced from Guodu Chemical (Kunshan) Co., Ltd., brand: YDF-2004

[0132] Comparative Example 4

[0133] A high conductivity, high stability and low temperature curing silver paste for inductance, compared with Example 2, the only difference is:

[0134] In the epoxy resin carrier, epoxy resin D is used to replace epoxy resin A in equal amount; epoxy resin E is used to replace epoxy resin B in equal amount; epoxy resin F is used to replace epoxy resin C in equal amount.

[0135] Epoxy resin D is bisphenol A epoxy resin, which comes from Kunshan Nanya Epoxy Resin Company, brand: NPES-901H.

[0136] Epoxy resin E is bisphenol A epoxy resin, sourced from Guodu Chemical (Kunshan) Co., Ltd., brand: YD-019 *4 .

[0137] Epoxy resin F is bisphenol F type epoxy resin, sourced from Guodu Chemical (Kunshan) Co., Ltd., brand: YDF-2004

[0138] Comparative Example 5

[0139] A high conductivity, high stability and low temperature curing silver paste for inductance, compared with Example 2, the only difference is:

[0140] In the curing agent, an equal amount of adipic acid dihydrazide is used to replace phenolic resin A.

[0141] Adipic acid dihydrazide is commercially available, CAS number: 1071-93-8.

[0142] Comparative Example 6

[0143] A high conductivity, high stability and low temperature curing silver paste for inductance, compared with Example 2, the only difference is:

[0144] In the curing agent, methyltetrahydrophthalic anhydride is used to replace the phenolic resin B in an equal amount.

[0145] Methyltetrahydrophthalic anhydride is commercially available, CAS number: 11070-44-3.

[0146] Comparative Example 7

[0147] A high conductivity, high stability and low temperature curing silver paste for inductance, compared with Example 2, the only difference is:

[0148] In the curing agent, an equal amount of adipic acid dihydrazide is used to replace the phenolic resin A; an equal amount of methyltetrahydrophthalic anhydride is used to replace the phenolic resin B.

[0149] Adipic acid dihydrazide is commercially available, CAS number: 1071-93-8.

[0150] Methyltetrahydrophthalic anhydride is commercially available, CAS number: 11070-44-3.

[0151] Performance Testing

[0152] The low-temperature curing silver paste prepared in each embodiment and comparative example was made into a 1*1*0.016cm square conductive silver film material on a polyimide substrate, and placed in an oven at 110°C for 15 minutes; in addition, the electrodes at both ends of the one-piece molded inductor were sealed, and the paste thickness was 0.06cm, and then placed in a blast oven and baked at 110°C for 15 minutes. After the substrate was sealed and dried at both ends, the square conductive silver film and the inductor were placed in a blast oven at 180°C for 90 minutes. After the cured samples of embodiments 1-3 and comparative examples 1-7 were tested, 100 inductor samples and square conductive silver films were taken from each group, and the test results were averaged. The test content is as follows:

[0153] (1) Silver film square resistance and inductor DC resistance (DCR) test: Use a DC resistance tester to test the square resistance of the silver film and the DC resistance of the inductor after termination and curing.

[0154] (2) L&Q value test: Use an LCR tester to test the L value and Q value of the inductor after the end capping and curing.

[0155] (3) Soldering tension: The inductor is soldered to the PCB through reflow soldering, and the soldering tension is tested using a tension testing machine.

[0156] (4) Solder resistance: According to the requirements of GB / T 5095.6-1997, use a soldering furnace to test the inductor after termination and curing to observe whether the silver layer is damaged.

[0157] (5) PCT test: Use a high pressure cooking tester to perform the test in accordance with the requirements of JESD22-A102 standard.

[0158] (6) Size, flatness and sag: The size of the two ends of the inductor is measured with a micrometer, and the flatness and sag are measured visually.

[0159] (7) Paste viscosity and DCR stability test: The low-temperature silver paste prepared above was placed at room temperature for 60 days (the day of placement was not counted), and the viscosity of the low-temperature silver paste, the resistance of the square silver film made on the same day, the resistance of the inductor after end-capping and curing were tested using a Brookfield DV2T viscometer and a DC resistance meter on the same day, the first day, the 14th day, the 28th day, and the 60th day. The test results of long-term viscosity and resistance are shown in Table 2. The viscosity is the average viscosity of the test at 10 rpm for 2 minutes, in cp, and the resistance is in mΩ.

[0160] The magnifying glass pictures of the front and end faces of the inductor after the termination and curing of each embodiment and comparative example are as follows: Figure 1 described.

[0161] The test results are shown in Tables 1 and 2:

[0162] Table 1

[0163]

[0164]

[0165] Table 2

[0166]

[0167]

[0168] According to the data comparison of Table 1 and Table 2, the square resistance and DC resistance of each embodiment are significantly lower than those of the comparative examples, and other stability performances are better. When the comparative examples are replaced with other epoxy resins or phenolic resins, the square resistance and DC resistance are increased, the welding tension is decreased, and the PCT detection failure rate is high and the soldering resistance is poor. This proves that only when epoxy resin A, epoxy resin B, epoxy resin C, phenolic resin A, and phenolic resin B are compounded can a special network structure be formed, so that the low-temperature curing silver paste has both high conductivity and high stability.

[0169] After long-term storage, the DC resistance, square resistance and viscosity of each embodiment have no significant changes. A small amount of solvent will evaporate during storage at room temperature, so the viscosity will increase slightly, but the effect is not significant. When the comparative examples are parked for 28 days, the DC resistance, square resistance and viscosity begin to change significantly. It can be seen that the long-term storage stability of the silver paste of each embodiment is significantly better than that of each comparative example.

[0170] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A high conductivity, high stability, low temperature curing silver paste for inductors, characterized in that: The composition includes the following components in parts by weight: 50-70 parts of spherical silver powder; 10-30 parts of flaky silver powder; Epoxy resin carrier 20-21 parts; 1-3 parts of curing agent; Curing accelerator 0.1-1 part; Additives 0.1-1 part; The epoxy resin carrier is prepared by dissolving epoxy resin in an organic solvent; The epoxy resin is a compound of epoxy resin A, epoxy resin B and epoxy resin C; The curing agent is a compound of phenolic resin A and phenolic resin B; The epoxy resin A is bisphenol A epoxy resin, which is from Kunshan Nanya Epoxy Resin Company, brand: NPES901; The epoxy resin B is bisphenol A epoxy resin, which is from Guodu Chemical (Kunshan) Co., Ltd., brand: YD017H; The epoxy resin C is bisphenol F epoxy resin, which is from Guodu Chemical (Kunshan) Co., Ltd., brand: YDF2001; The phenolic resin A is bisphenol A phenolic resin, which is sourced from Jinan Shengquan Group Co., Ltd. The phenolic resin B is o-cresol-formaldehyde resin, which is sourced from Suzhou Senfida Chemical Co., Ltd.

2. According to claim 1, a high conductivity, high stability, low temperature curing silver paste for inductance, characterized in that: The spherical silver powder has a D50 of 3.0-5.0 microns and a tap density of 4.5-6.0 g / cm 3 .

3. According to claim 1, a high conductivity, high stability, low temperature curing silver paste for inductance, characterized in that: The D50 of the flaky silver powder is 1.0-2.0 microns, and the tap density is 4.0-5.0 g / cm 3 .

4. The high conductivity, high stability and low temperature curing silver paste for inductance according to claim 1, characterized in that: In the epoxy resin carrier, the mass ratio of epoxy resin to organic solvent is 40-60:40-60.

5. The high conductivity, high stability and low temperature curing silver paste for inductance according to claim 1, characterized in that: The mass ratio of the epoxy resin A, epoxy resin B and epoxy resin C is 10-18:15-21:15-21.

6. The high conductivity, high stability and low temperature curing silver paste for inductance according to claim 1, characterized in that: The mass ratio of the phenolic resin A to the phenolic resin B is 0.4-1.4:0.6-1.

6.

7. The high conductivity, high stability and low temperature curing silver paste for inductance according to claim 1, characterized in that: The organic solvent is one or more of butanol, diethylene glycol ethyl ether, diethylene glycol ethyl ether acetate, diethylene glycol butyl ether, diethylene glycol butyl ether acetate, pinene alcohol, and ethylene glycol ethyl ether.

8. The high conductivity, high stability and low temperature curing silver paste for inductance according to claim 1, characterized in that: The curing accelerator is an amine curing accelerator.

9. The high conductivity, high stability and low temperature curing silver paste for inductance according to claim 1, characterized in that: The auxiliary agent is one or more of thixotropic agent fumed silica, polyamide wax, and hydrogenated castor oil.

10. A method for preparing a high conductivity, high stability and low temperature curing silver paste for inductance according to any one of claims 1 to 9, characterized in that: The following steps are involved: Step 1), the epoxy resin carrier, curing agent, curing accelerator and auxiliary agent are mixed evenly to obtain a resin solution; Step 2), spherical silver powder and flaky silver powder are put into the resin solution, mixed evenly, and ground to obtain high conductivity, high stability, and low temperature curing silver paste for inductor.

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