Low-temperature curing conductive silver paste with good conductive effect and preparation method thereof

Abstract

The invention provides low-temperature curing conductive silver paste with a good conductive effect and a preparation method of the low-temperature curing conductive silver paste, and relates to the technical field of conductive silver paste. 7 to 12 parts of polymer resin; 20 to 30 parts of an organic solvent; 1-3 parts of a plasticizer; 5-10 parts of a conductive filler; a conductive enhancer; according to the conductive silver paste, the conductive filler and the conductive enhancer are combined, so that the conductive effect of the conductive silver paste is improved, the mechanical strength of a cured conductive silver paste circuit is also improved, the integrity of the circuit is further ensured, the conductive performance of the circuit is improved, and the conductive silver paste is more suitable for the field with high requirements on the mechanical strength; the adhesive is suitable for bonding, packaging and the like of electronic components.

Description

Technical Field

[0001] The invention relates to the technical field of conductive silver paste, and in particular to a low-temperature curing conductive silver paste with good conductive effect and a preparation method thereof. Background Art

[0002] Low-temperature curing conductive silver paste is a paste-like conductive material mixed with metallic silver powder, polymer resin binder phase, solvent and a variety of additives. The main feature of this material is that it can be cured at a relatively low temperature (usually below 250°C), so it is particularly suitable for use on electronic components or flexible substrates that are sensitive to high temperatures. Its main function is to form a conductive path through the conductivity provided by silver powder. It is widely used in membrane switches, printed circuit boards, solar cells and other fields. The current low-temperature curing silver paste also has the following defects: conductive fillers or conductive enhancers are usually used alone to improve the conductivity, but there is a problem of insufficient mechanical strength while improving the conductivity, resulting in insufficient bonding strength with the substrate, making the silver paste layer easy to fall off or separate, and easy to break or deform when subjected to external force, affecting the integrity and conductivity of the circuit. Due to insufficient mechanical strength, the conductive silver paste may not be suitable for application scenarios that require higher mechanical strength, such as flexible circuit boards or electronic devices that require high temperature and high voltage resistance, which limits the scope of use of the conductive silver paste. Summary of the invention

[0003] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a low-temperature curing conductive silver paste with good conductive effect and a preparation method thereof.

[0004] In order to achieve the above object, the present invention adopts the following technical scheme: a low-temperature curing conductive silver paste with good conductive effect, the composition and mass fraction of the conductive silver paste are:

[0005] Silver powder: 35-45 parts;

[0006] Polymer resin: 7-12 parts;

[0007] Organic solvent: 20-30 parts;

[0008] Plasticizer: 1-3 parts;

[0009] Conductive filler: 5-10 parts;

[0010] Conductivity enhancer: 7-15 parts.

[0011] Furthermore, the conductive filler is prepared from bisphenol A epoxy resin, anhydride curing agent, methylimidazole, butyl acetate, and active diluent 692.

[0012] Furthermore, the conductive enhancer is prepared from silver nanoparticles (Ag NPs), silver nanowires (Ag NWs), silver microfibers (Ag MFs), polyvidone urea (WPU), additives, organic solvents and water-soluble solvents.

[0013] Furthermore, the conductive filler is prepared by the following steps:

[0014] S101: Weigh appropriate amounts of 8-12 parts of bisphenol A epoxy resin, 1-3 parts of anhydride curing agent, 0-1 part of methylimidazole, 4-6 parts of butyl acetate and 6921-2 parts of active diluent according to mass fractions;

[0015] S102: Mix bisphenol A epoxy resin and anhydride curing agent in proportion and stir evenly;

[0016] S103: Subsequently, butyl acetate and active diluent 692 are added, wherein butyl acetate is used as an inactive diluent to adjust the viscosity, and the active diluent 692 participates in the curing reaction and becomes a part of the cured product;

[0017] S104: All components are thoroughly mixed using a high-speed mixer;

[0018] S105: Curing the mixed conductive additive at a temperature of 80-160° C. for 1-5 minutes to form a stable conductive network structure.

[0019] Furthermore, the conductive enhancer is prepared by the following steps:

[0020] S201: mixing silver nanoparticles (Ag NPs), silver nanowires (Ag NWs), silver microfibers (Ag MFs) and polyvidone urea (WPU);

[0021] S202: adding additives, organic solvents and water-soluble solvents;

[0022] S203: Finally, a curing treatment is performed to volatilize the organic solvent and the water-soluble solvent.

[0023] Furthermore, the additive in step S202 is Capston fs-31, the organic solvent is ethanol, isopropanol or dimethyl sulfoxide, and the water-soluble solvent is N-methylpyrrolidone (NMP) or ethylene glycol ether.

[0024] Furthermore, the silver powder is one of flaky silver powder, spherical silver powder, dendritic silver powder or rod-shaped silver powder.

[0025] The method for preparing the low-temperature curing conductive silver paste with good conductive effect comprises the following steps:

[0026] S1: weigh 35-45 parts of silver powder, 7-12 parts of polymer resin, 20-30 parts of organic solvent, 20-30 parts of organic solvent, 1-3 parts of plasticizer, 5-10 parts of conductive filler and 7-15 parts of conductive enhancer according to weight;

[0027] S2: Add the polymer resin and the organic solvent into a high-speed mixer, mix them at a speed of 350-450 r / min, and then cool them to 35-45° C. to obtain an organic carrier for standby use;

[0028] S3: adding the organic carrier, silver powder, conductive filler, conductive enhancer and plasticizer obtained in step S2 into a mixer and mixing them uniformly at a temperature of 30-40° C. and a stirring rate of 350-450 r / min to obtain a mixture;

[0029] S4: Grind the mixture in a three-roll grinder, degas it in a centrifugal degasser, and finally sieve it through a 500-700 mesh filter to remove residual impurities, thereby obtaining a low-temperature curing conductive silver paste.

[0030] Compared with the prior art, the advantages and positive effects of the present invention are:

[0031] In the present invention, by combining the conductive filler and the conductive enhancer, the conductive effect of the conductive silver paste is improved while the mechanical strength of the conductive silver paste is also improved, thereby ensuring the integrity and conductive performance of the circuit, making the conductive silver paste of the present application more suitable for fields with high requirements for mechanical strength, and suitable for applications such as bonding and packaging of electronic components. DETAILED DESCRIPTION

[0032] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described below in conjunction with embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict. Furthermore, in the description of the present invention, “plurality” means two or more than two, unless otherwise clearly and specifically defined.

[0034] The present invention provides a low-temperature curing conductive silver paste with good conductive effect. The composition and mass fraction of the conductive silver paste are:

[0035] Silver powder: 35-45 parts;

[0036] Polymer resin: 7-12 parts;

[0037] Organic solvent: 20-30 parts;

[0038] Plasticizer: 1-3 parts;

[0039] Conductive filler: 5-10 parts;

[0040] Conductivity enhancer: 7-15 parts.

[0041] In the present invention, the conductive filler is prepared from bisphenol A epoxy resin, anhydride curing agent, methylimidazole, butyl acetate and active diluent 692.

[0042] In the present invention, the conductive enhancer is prepared from silver nanoparticles (Ag NPs), silver nanowires (Ag NWs), silver microfibers (AgMFs), polyvidone urea (WPU), additives, organic solvents and water-soluble solvents.

[0043] In the present invention, the conductive filler is prepared by the following steps:

[0044] S101: weigh appropriate amounts of 30-40 parts of bisphenol A epoxy resin, 20-40 parts of anhydride curing agent, 10-20 parts of methylimidazole, 15-30 parts of butyl acetate and 10-20 parts of active diluent 692 according to their mass fractions;

[0045] S102: Mix bisphenol A epoxy resin and anhydride curing agent in proportion and stir evenly;

[0046] S103: Subsequently, butyl acetate and active diluent 692 are added, wherein butyl acetate is used as an inactive diluent to adjust the viscosity, and the active diluent 692 participates in the curing reaction and becomes a part of the cured product;

[0047] S104: All components are thoroughly mixed using a high-speed mixer;

[0048] S105: curing the mixed conductive additive at a temperature of 80-160° C. for 1-5 minutes to form a stable conductive network structure;

[0049] The conductive enhancer is prepared by the following steps:

[0050] S201: mixing silver nanoparticles (Ag NPs), silver nanowires (Ag NWs), silver microfibers (Ag MFs) and polyvidone urea (WPU);

[0051] S202: adding additives, organic solvents and water-soluble solvents;

[0052] S203: Finally, a curing treatment is performed to volatilize the organic solvent and the water-soluble solvent;

[0053] The additive in step S202 is Capston fs-31, the organic solvent is ethanol, isopropanol or dimethyl sulfoxide, and the water-soluble solvent is N-methylpyrrolidone (NMP) or glycol ether;

[0054] The silver powder is a kind of flaky silver powder, spherical silver powder, dendritic silver powder or rod-shaped silver powder.

[0055] The low-temperature curing conductive silver paste with good conductive effect and a preparation method thereof comprise the following steps:

[0056] S1: weigh 35-45 parts of silver powder, 7-12 parts of polymer resin, 20-30 parts of organic solvent, 20-30 parts of organic solvent, 1-3 parts of plasticizer, 5-10 parts of conductive filler and 7-15 parts of conductive enhancer according to weight;

[0057] S2: Add the polymer resin and the organic solvent into a high-speed mixer, mix them at a speed of 350-450 r / min, and then cool them to 35-45° C. to obtain an organic carrier for standby use;

[0058] S3: adding the organic carrier, silver powder, conductive filler, conductive enhancer and plasticizer obtained in step S2 into a mixer and mixing them uniformly at a temperature of 30-40° C. and a stirring rate of 350-450 r / min to obtain a mixture;

[0059] S4: Grind the mixture in a three-roll grinder, degas it in a centrifugal degasser, and finally sieve it through a 500-700 mesh filter to remove residual impurities, thereby obtaining a low-temperature curing conductive silver paste.

[0060] Several embodiments are given below:

[0061] Embodiment 1

[0062] S1: weigh 35 parts of silver powder, 7 parts of polymer resin, 20 parts of organic solvent, 20 parts of organic solvent, 1 part of plasticizer, 6 parts of conductive filler and 11 parts of conductive enhancer according to weight;

[0063] The conductive filler is prepared by the following steps:

[0064] S101: Weigh appropriate amounts of 30 parts of bisphenol A epoxy resin, 40 parts of anhydride curing agent, 10 parts of methylimidazole, 15 parts of butyl acetate and 69215 parts of reactive diluent according to their mass fractions;

[0065] S102: Mix bisphenol A epoxy resin and anhydride curing agent in proportion and stir evenly;

[0066] S103: Subsequently, butyl acetate and active diluent 692 are added, wherein butyl acetate is used as an inactive diluent to adjust the viscosity, and the active diluent 692 participates in the curing reaction and becomes a part of the cured product;

[0067] S104: All components are thoroughly mixed using a high-speed mixer;

[0068] S105: curing the mixed conductive additive at 80° C. for 5 minutes to form a stable conductive network structure;

[0069] The conductive enhancer is prepared by the following steps:

[0070] S201: mixing silver nanoparticles (Ag NPs), silver nanowires (Ag NWs), silver microfibers (Ag MFs) and polyvidone urea (WPU);

[0071] S202: adding additives, organic solvents and water-soluble solvents;

[0072] S203: Finally, a curing treatment is performed to volatilize the organic solvent and the water-soluble solvent;

[0073] S2: Add the polymer resin and the organic solvent into a high-speed mixer, mix them at a speed of 350 r / min, and then cool them to 35° C. to obtain an organic carrier for use;

[0074] S3: adding the organic carrier, silver powder, conductive filler, conductive enhancer and plasticizer obtained in step S2 into a mixer and mixing them uniformly at a temperature of 30° C. and a stirring rate of 350 r / min to obtain a mixture;

[0075] S4: Grind the mixture in a three-roll grinder, degas it in a centrifugal degasser, and finally sieve it through a 600-mesh filter to remove residual impurities, thereby obtaining a low-temperature curing conductive silver paste.

[0076] Embodiment 2

[0077] S1: Weigh 40 parts of silver powder, 7 parts of polymer resin, 25 parts of organic solvent, 20 parts of organic solvent, 1 part of plasticizer, 6 parts of conductive filler and 11 parts of conductive enhancer according to weight;

[0078] The conductive filler is prepared by the following steps:

[0079] S101: Weigh appropriate amounts of 30 parts of bisphenol A epoxy resin, 40 parts of anhydride curing agent, 10 parts of methylimidazole, 15 parts of butyl acetate and 6927 parts of reactive diluent according to their mass fractions;

[0080] S102: Mix bisphenol A epoxy resin and anhydride curing agent in proportion and stir evenly;

[0081] S103: Subsequently, butyl acetate and active diluent 692 are added, wherein butyl acetate is used as an inactive diluent to adjust the viscosity, and the active diluent 692 participates in the curing reaction and becomes a part of the cured product;

[0082] S104: All components are thoroughly mixed using a high-speed mixer;

[0083] S105: curing the mixed conductive additive at 100° C. for 3 minutes to form a stable conductive network structure;

[0084] The conductive enhancer is prepared by the following steps:

[0085] S201: mixing silver nanoparticles (Ag NPs), silver nanowires (Ag NWs), silver microfibers (Ag MFs) and polyvidone urea (WPU);

[0086] S202: adding additives, organic solvents and water-soluble solvents;

[0087] S203: Finally, a curing treatment is performed to volatilize the organic solvent and the water-soluble solvent;

[0088] S2: Add the polymer resin and the organic solvent into a high-speed mixer, mix them at a speed of 400 r / min, and then cool them to 40° C. to obtain an organic carrier for use;

[0089] S3: adding the organic carrier, silver powder, conductive filler, conductive enhancer and plasticizer obtained in step S2 into a mixer and mixing them uniformly at a temperature of 30° C. and a stirring rate of 4000 r / min to obtain a mixture;

[0090] S4: Grind the mixture in a three-roll grinder, degas it in a centrifugal degasser, and finally sieve it through a 700-mesh filter to remove residual impurities, thereby obtaining a low-temperature curing conductive silver paste.

[0091] Embodiment 3

[0092] S1: weigh 35 parts of silver powder, 7 parts of polymer resin, 20 parts of organic solvent, 20 parts of organic solvent, 2 parts of plasticizer, 9 parts of conductive filler and 7 parts of conductive enhancer according to weight parts;

[0093] The conductive filler is prepared by the following steps:

[0094] S101: Weigh appropriate amounts of 32 parts of bisphenol A epoxy resin, 25 parts of anhydride curing agent, 15 parts of methylimidazole, 20 parts of butyl acetate and 6928 parts of reactive diluent according to their mass fractions;

[0095] S102: Mix bisphenol A epoxy resin and anhydride curing agent in proportion and stir evenly;

[0096] S103: Subsequently, butyl acetate and active diluent 692 are added, wherein butyl acetate is used as an inactive diluent to adjust the viscosity, and the active diluent 692 participates in the curing reaction and becomes a part of the cured product;

[0097] S104: All components are thoroughly mixed using a high-speed mixer;

[0098] S105: curing the mixed conductive additive at 110° C. for 2 minutes to form a stable conductive network structure;

[0099] The conductive enhancer is prepared by the following steps:

[0100] S201: mixing silver nanoparticles (Ag NPs), silver nanowires (Ag NWs), silver microfibers (Ag MFs) and polyvidone urea (WPU);

[0101] S202: adding additives, organic solvents and water-soluble solvents;

[0102] S203: Finally, a curing treatment is performed to volatilize the organic solvent and the water-soluble solvent;

[0103] S2: Add the polymer resin and the organic solvent into a high-speed mixer, mix them at a speed of 400 r / min, and then cool them to 40° C. to obtain an organic carrier for use;

[0104] S3: adding the organic carrier, silver powder, conductive filler, conductive enhancer and plasticizer obtained in step S2 into a mixer and mixing them uniformly at a temperature of 30° C. and a stirring rate of 400 r / min to obtain a mixture;

[0105] S4: Grind the mixture in a three-roll grinder, degas it in a centrifugal degasser, and finally sieve it through a 500-mesh filter to remove residual impurities, thereby obtaining a low-temperature curing conductive silver paste.

[0106] The above are only preferred embodiments of the present invention and are not intended to limit the present invention in other forms. Any technician familiar with the profession may use the technical contents disclosed above to change or modify them into equivalent embodiments with equivalent changes and apply them to other fields. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the technical solution of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A low temperature curing conductive silver paste with good conductive effect, characterized in that: The composition and mass fraction of the conductive silver paste are: Silver powder: 35-45 parts; Polymer resin: 7-12 parts; Organic solvent: 20-30 parts; Plasticizer: 1-3 parts; Conductive filler: 5-10 parts; Conductivity enhancer: 7-15 parts.

2. The low-temperature curing conductive silver paste with good conductive effect according to claim 1, characterized in that: The conductive filler is prepared from bisphenol A epoxy resin, anhydride curing agent, methylimidazole, butyl acetate and active diluent 692.

3. The low-temperature curing conductive silver paste with good conductive effect according to claim 1, characterized in that: The conductive enhancer is prepared from silver nanoparticles, silver nanowires, silver microfibers, polyvidone urea, additives, organic solvents and water-soluble solvents.

4. The low-temperature curing conductive silver paste with good conductive effect according to claim 2, characterized in that: The conductive filler is prepared by the following steps: S101: Weigh appropriate amounts of 8-12 parts of bisphenol A epoxy resin, 1-3 parts of anhydride curing agent, 0-1 part of methylimidazole, 4-6 parts of butyl acetate and 6921-2 parts of active diluent according to mass fractions; S102: Mix bisphenol A epoxy resin and anhydride curing agent in proportion and stir evenly; S103: Subsequently, butyl acetate and active diluent 692 are added, wherein butyl acetate is used as an inactive diluent to adjust the viscosity, and the active diluent 692 participates in the curing reaction and becomes a part of the cured product; S104: All components are thoroughly mixed using a high-speed mixer; S105: Curing the mixed conductive additive at a temperature of 80-160° C. for 1-5 minutes to form a stable conductive network structure.

5. The low temperature curing conductive silver paste with good conductive effect according to claim 3, characterized in that: The conductive enhancer is prepared by the following steps: S201: mixing silver nanoparticles (Ag NPs), silver nanowires (Ag NWs), silver microfibers (Ag MFs) and polyvidone urea (WPU); S202: adding additives, organic solvents and water-soluble solvents; S203: Finally, a curing treatment is performed to volatilize the organic solvent and the water-soluble solvent.

6. The low-temperature curing conductive silver paste with good conductive effect according to claim 5, characterized in that: The additive in step S202 is Capston fs-31, the organic solvent is ethanol, isopropanol or dimethyl sulfoxide, and the water-soluble solvent is N-methylpyrrolidone NMP or ethylene glycol ether.

7. The low-temperature curing conductive silver paste with good conductive effect according to claim 1, characterized in that: The silver powder is one of flaky silver powder, spherical silver powder, dendritic silver powder or rod-shaped silver powder.

8. The method for preparing a low-temperature curing conductive silver paste with good conductive effect according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1: weigh 35-45 parts of silver powder, 7-12 parts of polymer resin, 20-30 parts of organic solvent, 20-30 parts of organic solvent, 1-3 parts of plasticizer, 5-10 parts of conductive filler and 7-15 parts of conductive enhancer according to weight; S2: Add the polymer resin and the organic solvent into a high-speed mixer, mix them at a speed of 350-450 r / min, and then cool them to 35-45° C. to obtain an organic carrier for standby use; S3: adding the organic carrier, silver powder, conductive filler, conductive enhancer and plasticizer obtained in step S2 into a mixer and mixing them uniformly at a temperature of 30-40° C. and a stirring rate of 350-450 r / min to obtain a mixture; S4: Grind the mixture in a three-roll grinder, degas it in a centrifugal degasser, and finally sieve it through a 500-700 mesh filter to remove residual impurities, thereby obtaining a low-temperature curing conductive silver paste.