CN115954136A - Transparent high-temperature sintered silver paste and preparation method, use method and application thereof - Google Patents

Abstract

The invention provides a transparent high-temperature sintered silver paste and its preparation method, use method and application, and specifically relates to the technical field of conductive silver paste. The transparent high-temperature sintered silver paste comprises 15%-20% of silver powder, 60%-80% of polyamide/polyaniline conductive mixture, 3%-15% of glass powder and 2%-22% of solvent. The transparent high-temperature sintered silver paste adds a polyamide/polyaniline conductive mixture to the raw material to improve the transparency and conductivity of the silver paste. The silver powder, polyamide/polyaniline conductive mixture, glass powder and solvent in the raw materials cooperate with each other to improve the transparency, conductivity, dispersion performance and printing performance of the silver paste. The resistivity of the transparent high-temperature sintered silver paste provided by the invention is 2×10 ^‑6 Ω·cm～4×10 ^‑6 Ω·cm; the adhesion test grade is 5B, and it has better bending resistance and adhesion.

Description

Transparent high-temperature sintered silver paste and its preparation method, use method and application

technical field

The invention relates to the technical field of conductive silver paste, in particular to a transparent high-temperature sintered silver paste and its preparation method, use method and application.

Background technique

With the development of society and economy, the demand for energy and electronics continues to grow. Many high-performance core electronic materials, such as conductive silver paste, have long been monopolized by foreign technologies, and high-temperature conductive silver paste is the main material for high-performance electronics. , The key material of low-cost high-performance electronics.

In the existing high-temperature conductive silver paste, in order to make the silver paste have good printability, a large amount of organic carriers are added. Excessive use of these auxiliary materials usually affects the performance of the silver paste: for example, the use of a large amount of organic mixture will make The conductivity of the silver paste is reduced.

In order to obtain good and high-efficiency conductivity, a large amount of silver powder is added to increase the cost of silver paste. At the same time, a large amount of silver powder will also affect the dispersion performance of silver paste, which is not conducive to the post-printing of silver paste.

In view of this, the present invention is proposed.

Contents of the invention

One of the objectives of the present invention is to provide a transparent high-temperature sintered silver paste to alleviate the technical problems of low electrical conductivity, poor dispersion performance affecting printing and high cost in the prior art.

In order to solve the problems of the technologies described above, the present invention adopts the following technical solutions:

The first aspect of the present invention provides a transparent high-temperature sintered silver paste, including the following raw materials: silver powder, polyamide/polyaniline conductive mixture, glass powder and solvent.

Optionally, the raw materials include the following mass fractions: 15%-20% of silver powder, 60%-80% of polyamide/polyaniline conductive mixture, 3%-15% of glass powder and 2%-22% of solvent.

Optionally, the solvent includes at least one of isophorone, butyl anhydride acetate, diethylene glycol butyl ether acetate and diethylene glycol ethyl ether acetate.

Optionally, in the polyamide/polyaniline conductive mixture, the mass ratio of polyamide to polyaniline is (1-4):5.

The second aspect of the present invention provides the preparation method of described transparent high-temperature sintered silver paste, comprising the following steps:

Step A: uniformly mixing the polyamide/polyaniline conductive mixture with a solvent to obtain a polyamide/polyaniline conductive mixture solution;

Step B: mixing silver powder and glass powder evenly and then grinding to obtain mixed powder;

Step C: Add the mixed powder obtained in Step B into the polyamide/polyaniline conductive mixture solution in Step A and mix evenly to obtain a transparent high-temperature sintered silver paste.

Optionally, in step B, the particle size of the mixed powder is ≤4.5 μm.

Optionally, in step C, the viscosity of the transparent high-temperature sintered silver paste is 10000mPa·s-12000mPa·s.

The third aspect of the present invention provides a method for using the transparent high-temperature sintered silver paste, printing the transparent high-temperature sintered silver paste on a device, and then sintering to obtain a silver conductive layer.

Optionally, the sintering temperature is 700°C-950°C;

Preferably, the sintering time is 5 min-10 min.

The fourth aspect of the present invention provides the application of the transparent high-temperature sintered silver paste in PCB boards, microelectronics or solar panels.

Compared with the prior art, the present invention has at least the following beneficial effects:

The transparent high-temperature sintered silver paste provided by the invention adds a polyamide/polyaniline conductive mixture to the raw material, wherein the polyamide molecular chain contains a certain number of amide groups, and its chemical structure determines that it can form hydrogen bonds with polyaniline They adsorb each other to form a mixture; and the main chain of polyaniline contains alternating benzene rings and nitrogen atoms, which is a special conductive polymer. Both polyaniline and polyamide are conductive polymers. When polyaniline is compounded with polyamide polymer materials, its application in silver paste can partially replace the adhesive resin, and it will have good processability and mechanical properties at the same time. Moreover, the conductive composite material with controllable conductivity improves the transparency and conductivity of the silver paste. The glass powder improves the sintering performance of the silver paste and the glass substrate, and improves the bonding force. The overall cooperation of silver powder, polyamide/polyaniline conductive mixture, glass powder and solvent improves the transparency, conductivity, dispersion performance and printing performance of silver paste. The resistivity of the transparent high-temperature sintered silver paste provided by the invention is 2×10 ^-6 Ω·cm to 4×10 ^-6 Ω·cm, the adhesion test grade is 5B, and has better bending resistance and adhesion.

The preparation method provided by the invention is simple, has large processing capacity, low cost and high method repeatability, and is favorable for large-scale production.

The use method provided by the invention is simple, the mechanical operation is convenient, the processing capacity is large, and it is beneficial to large-scale operation.

The application provided by the invention provides conductive silver paste with better performance and lower cost for PCB boards, microelectronics and solar battery panels, and improves the connection and photoelectric conversion efficiency of circuits in PCB boards, microelectronics and solar battery panels.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention , but not all examples. The components of embodiments of the invention may be arranged and designed in a variety of different configurations.

It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is a relationship between these entities or operations. There is no such actual relationship or order between them. Furthermore, the term "comprises", "comprises" or any other variation thereof is intended to cover a non-exclusive inclusion such that a process, method, article, or apparatus comprising a set of elements includes not only those elements, but also includes elements not expressly listed. other elements of or also include elements inherent in such a process, method, article, or device.

In the present invention, if there is no special description on the temperature, it means normal temperature or room temperature, that is, the relevant operations do not need to consider the influence of temperature, and do not need heating or cooling treatment.

A transparent high-temperature sintered silver paste according to the first aspect of the present invention includes the following raw materials: silver powder, polyamide/polyaniline conductive mixture, glass powder and solvent.

The transparent high-temperature sintered silver paste provided by the invention adds a polyamide/polyaniline conductive mixture to the raw material, wherein the polyamide molecular chain contains a certain number of amide groups, and its chemical structure determines that it can form hydrogen bonds with polyaniline They adsorb each other to form a mixture; and the main chain of polyaniline contains alternating benzene rings and nitrogen atoms, which is a special conductive polymer. When the polyaniline is compounded with the polyamide polymer material, a conductive composite material with good processability and mechanical properties and controllable conductivity will be obtained, which improves the transparency and conductivity of the silver paste. The glass powder improves the sintering performance of the silver paste and the glass substrate, and improves the bonding force. The overall cooperation of silver powder, polyamide/polyaniline conductive mixture, glass powder and solvent improves the transparency, conductivity, dispersion performance and printing performance of silver paste. The resistivity of the transparent high-temperature sintered silver paste provided by the invention is 2×10 ^-6 Ω·cm to 4×10 ^-6 Ω·cm; the adhesion test grade is 5B, and has better bending resistance and adhesion.

The polyamide/polyaniline conductive mixture, glass powder and solvent form the carrier, and the components shrink through the self-curing process, so that the silver powder dispersed in it contacts each other to form a conductive network.

The solvent dissolves the polyamide/polyaniline conductive mixture to adjust the dispersion, viscosity, printability of the conductive silver paste, and the wettability of the conductive silver paste and the substrate.

Optionally, the raw materials include the following mass fractions: 15%-20% of silver powder, 60%-80% of polyamide/polyaniline conductive mixture, 3%-15% of glass powder and 2%-22% of solvent.

When the mass fraction of the silver powder is lower than 15%, the silver particles cannot be effectively connected to the molecular network structure of the polymer to form a conductive network body, resulting in an excessively high resistivity; when the mass fraction of the silver powder is higher than 20%, the silver particles are easily in Agglomeration in organic solvent matrix, poor dispersibility. When the mass fraction of the polyamide/polyaniline conductive mixture is lower than 60%, the silver particles cannot be effectively connected into a conductive network body, resulting in too high resistivity, and also prolonging the sintering and curing time; when the polyamide/polyaniline conductive When the mass fraction of the mixture is higher than 80%, the viscosity of the transparent high-temperature sintered silver paste becomes high and the dispersibility becomes poor. When the mass fraction of the glass powder is lower than 3%, the sintering performance with the glass substrate is affected, and the adhesion is not good; when the mass fraction of the glass powder is higher than 15%, the conductivity becomes smaller.

In some embodiments of the present invention, the mass fraction of silver powder in the transparent high-temperature sintered silver paste is typically but not limited to 15%, 16%, 17%, 18%, 19% or 20%; the mass fraction of polyamide/polyaniline conductive mixture The fraction is typically but not limited to 60%, 65%, 70%, 75% or 80%; the mass fraction of glass powder is typically but not limited to 3%, 6%, 9%, 12% or 15%; the mass fraction of solvent is typically but not limited to Not limited to 2%, 7%, 12%, 17% or 22%.

Optionally, the solvent includes at least one of isophorone, butyl anhydride acetate, diethylene glycol butyl ether acetate and diethylene glycol ethyl ether acetate.

Optionally, in the polyamide/polyaniline conductive mixture, the mass ratio of polyamide to polyaniline is 1-4:5.

When the mass ratio of polyamide to polyaniline is lower than 1:5, the antistatic performance of the silver paste is poor and the stability is poor; when the mass ratio of polyamide to polyaniline is higher than 4:5, the transparent high-temperature sintered The resistivity of silver paste is high.

In some embodiments of the present invention, in the polyamide/polyaniline conductive mixture, the mass ratio of polyamide to polyaniline is typically but not limited to 1:5, 2:5, 3:5 or 4:5.

The second aspect of the present invention provides the preparation method of described transparent high-temperature sintered silver paste, comprising the following steps:

Step A: uniformly mixing the polyamide/polyaniline conductive mixture with a solvent to obtain a polyamide/polyaniline conductive mixture solution;

Step B: mixing silver powder and glass powder evenly and then grinding to obtain mixed powder;

Step C: Add the mixed powder obtained in Step B into the polyamide/polyaniline conductive mixture solution in Step A and mix evenly to obtain a transparent high-temperature sintered silver paste.

The preparation method provided by the invention is simple, has large processing capacity, low cost and high method repeatability, and is favorable for large-scale production.

Optionally, in step B, the particle size of the mixed powder is ≤4.5 μm.

When the particle size of the mixed powder is not greater than 4.5 μm, the smaller the particle size in the transparent high-temperature sintered silver paste, the denser the silver powder will be filled and the lower the required curing temperature will be. When the particle size of the silver powder is larger than 4.5 μm, the space between the silver powder particles is easily filled by the carrier, which affects the formation of conductive paths between the conductive particles and affects the performance of the transparent high-temperature sintered silver paste.

Optionally, in step C, the viscosity of the transparent high-temperature sintered silver paste is 10000mPa·s-12000mPa·s.

In some embodiments of the present invention, the viscosity of the transparent high-temperature sintered silver paste is typically but not limited to 10000 mPa·s, 11000 mPa·s or 12000 mPa·s.

The third aspect of the present invention provides a method for using the transparent high-temperature sintered silver paste, printing the transparent high-temperature sintered silver paste on a device, and then sintering to obtain a silver conductive layer.

The use method provided by the invention is simple, the mechanical operation is convenient, the processing capacity is large, and it is beneficial to large-scale operation.

Optionally, the sintering temperature is 700°C-950°C.

In some embodiments of the present invention, the sintering temperature is typically but not limited to 700°C, 750°C, 800°C, 850°C, 900°C or 950°C.

Preferably, the sintering time is 5 min-10 min.

In some embodiments of the present invention, the sintering time is typically but not limited to 5 min, 6 min, 7 min, 8 min, 9 min or 10 min.

The fourth aspect of the present invention provides the application of the transparent high-temperature sintered silver paste in PCB boards, microelectronics and solar panels.

The application provided by the invention provides conductive silver paste with better performance and lower cost for PCB boards, microelectronics and solar battery panels, and improves the connection and photoelectric conversion efficiency of circuits in PCB boards, microelectronics and solar battery panels.

Below in conjunction with the examples, some embodiments of the present invention will be described in detail. In the case of no conflict, the following embodiments and features in the embodiments can be combined with each other.

The raw materials used in the examples and comparative examples of the present invention do not indicate specific conditions, and are carried out according to conventional conditions or conditions suggested by the manufacturer.

Example 1

This embodiment provides a transparent high-temperature sintered silver paste. The raw materials include 17kg of silver powder, 70kg of polyamide/polyaniline conductive mixture, 9kg of glass powder and 4kg of isophorone; among them, in the polyamide/polyaniline conductive mixture, polyamide and polyaniline The mass ratio of aniline is 1:2. The glass powder is Bi ₂ 0 ₃ -CuO-SiO ₂ system glass powder.

The preparation process of the transparent high-temperature sintered silver paste is as follows:

1. Mix polyamide and polyaniline evenly according to the mass ratio, then add part of isophorone to mix, and stir at room temperature at a speed of 1000 rpm until the system is completely mixed until it becomes transparent and stops stirring to obtain polyamide/ Polyaniline conductive mixture solution.

2. Mix silver powder and glass powder completely at room temperature, add a little isophorone to wet the mixed powder, then grind the mixed powder with a grinder, and measure the particle size of the mixed powder to be 4um.

3. Stir and mix the above mixed powder and polyamide/polyaniline conductive mixture solution at room temperature at a speed of 1000 rpm, add the remaining isophorone until a uniform silver paste is formed, and its viscosity is measured to be 11000mP.S.

Example 2

This embodiment provides a transparent high-temperature sintered silver paste. The raw materials include 15kg of silver powder, 60kg of polyamide/polyaniline conductive mixture, 15kg of glass powder and 10kg of isophorone; wherein polyamide/polyaniline conductive mixture, polyamide and polyaniline The mass ratio of aniline is 1:2.

The preparation method of the transparent high-temperature sintered silver paste is the same as that in Example 1, and will not be repeated here.

Example 3

This embodiment provides a transparent high-temperature sintered silver paste. The raw materials include 20kg of silver powder, 70kg of polyamide/polyaniline conductive mixture, 3kg of glass powder and 7kg of isophorone; among them, in the polyamide/polyaniline conductive mixture, polyamide and polyaniline The mass ratio of aniline is 1:2.

The preparation method of the transparent high-temperature sintered silver paste is the same as that in Example 1, and will not be repeated here.

Example 4

This embodiment provides a transparent high-temperature sintered silver paste. The raw materials include 15kg of silver powder, 80kg of polyamide/polyaniline conductive mixture, 3kg of glass powder and 2kg of butyl soluble anhydride acetate; wherein in the polyamide/polyaniline conductive mixture, polyamide and The mass ratio of polyaniline is 1:2.

The preparation method of the transparent high-temperature sintered silver paste is the same as that in Example 1, and will not be repeated here.

Example 5

This embodiment provides a transparent high-temperature sintered silver paste. The difference from Example 1 is that in the polyamide/polyaniline conductive mixture, the mass ratio of polyamide to polyaniline is 1:5, and the rest of the raw materials and steps are the same as in Example 1. Same, no more details here.

Example 6

This embodiment provides a transparent high-temperature sintered silver paste. The difference from Example 1 is that in the polyamide/polyaniline conductive mixture, the mass ratio of polyamide to polyaniline is 4:5, and the rest of the raw materials and steps are the same as in Example 1. Same, no more details here.

Example 7

This embodiment provides a transparent high-temperature sintered silver paste. The difference from Embodiment 1 is that the particle size of the mixed powder is controlled at 3 μm during the preparation process, and the rest of the raw materials and steps are the same as in Embodiment 1, and will not be repeated here.

Comparative example 1

This comparative example provides a conductive silver paste, and the raw materials include 75kg of silver powder, 2.5kg of glass powder, 4.5kg of resin and 18kg of organic solvent.

The glass powder is Bi ₂ 0 ₃ -CuO-SiO ₂ system glass powder.

The resin is ethyl cellulose and polyamide wax, and the mass ratio of ethyl cellulose and polyamide wax is 3.5:1.0.

The organic solvent is terpineol, isooctyl alcohol and diethylene glycol butyl ether acetate, and the mass ratio of terpineol, isooctyl alcohol and diethylene glycol butyl ether acetate is 6:1:3.

The preparation process of this conductive silver paste is as follows:

1. Dissolve ethyl cellulose and polyamide wax in a mixed solvent of part of terpineol and isooctyl alcohol, and stir evenly to form an organic vehicle. In the organic solvent, the quality of ethyl cellulose and polyamide wax and the mixed solvent The mass ratio is 35:65.

2. Dissolve the silver powder, glass powder and the rest of the organic solvent in the above-mentioned organic carrier, and then use mechanical stirring and grinding to disperse the mixture uniformly to obtain a conductive silver paste.

Comparative example 2

This comparative example provides a conductive silver paste. The difference from Example 1 is that polyamide is used instead of the polyamide/polyaniline conductive mixture, and the rest of the raw materials and preparation steps are the same as in Example 1, which will not be repeated here.

Comparative example 3

This comparative example provides a conductive silver paste, which is different from Example 1 in that polyaniline is used instead of the polyamide/polyaniline conductive mixture, and the rest of the raw materials and preparation steps are the same as in Example 1, and will not be repeated here.

Test example 1

The conductive silver paste obtained in Examples 1-7 and Comparative Examples 1-3 was printed on a glass substrate using a screen printing technique. The printed silver paste was cured in an oven at 850°C for 8 minutes.

Test example 2

The silver conductive layer obtained in Test Example 1 was subjected to a resistivity test and an adhesion test.

The specific test process is as follows:

Resistivity test: Use a resistance meter to test the meter resistance.

Adhesion test: 3M 600 tape is used for adhesion test, and whether it is peeled off is used as the standard for passing or not.

The above test data are recorded in Table 1.

Table 1 performance data table of silver conductive layer

It can be seen from Table 1 that the higher the silver powder content, the higher the conductivity of the silver paste and the lower the resistivity; under the premise of a certain organic to conductive polymer, the higher the content of polyamide, the higher the conductivity of the silver paste . The higher the glass powder content, the worse the conductivity.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting 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: It is still possible to modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the various embodiments of the present invention. scope.

Claims (10)

1. A transparent high-temperature sintered silver paste is characterized in that it comprises the following raw materials: silver powder, polyamide/polyaniline conductive mixture, glass powder and solvent. 2. The transparent high-temperature sintered silver paste according to claim 1, characterized in that it comprises the following raw materials in mass fraction: silver powder 15%-20%, polyamide/polyaniline conductive mixture 60%-80%, glass powder 3% -15% and solvent 2% -22%. 3. The transparent high-temperature sintered silver paste according to claim 1 or 2, characterized in that, the solvent comprises isophorone, butyl soluble anhydride acetate, diethylene glycol butyl ether acetate and diethylene glycol ethyl ether acetate at least one of esters. 4. The transparent high-temperature sintered silver paste according to claim 1 or 2, characterized in that, in the polyamide/polyaniline conductive mixture, the mass ratio of polyamide to polyaniline is (1-4):5. 5. a preparation method of the transparent high-temperature sintered silver paste described in any one of claims 1-4, is characterized in that, comprises the following steps: Step A: uniformly mixing the polyamide/polyaniline conductive mixture with a solvent to obtain a polyamide/polyaniline conductive mixture solution; Step B: mixing silver powder and glass powder evenly and then grinding to obtain mixed powder; Step C: Add the mixed powder obtained in Step B into the polyamide/polyaniline conductive mixture solution in Step A and mix evenly to obtain a transparent high-temperature sintered silver paste. 6. The preparation method according to claim 5, characterized in that, in step B, the particle size of the mixed powder is ≤4.5 μm. 7. The preparation method according to claim 5, wherein in step C, the viscosity of the transparent high-temperature sintered silver paste is 10000mPa·s-12000mPa·s. 8. A method for using the transparent high-temperature sintered silver paste according to any one of claims 1-4, wherein the transparent high-temperature sintered silver paste is printed on a device, and then sintered to obtain a silver conductive layer. 9. The use method according to claim 8, characterized in that the sintering temperature is 700°C-950°C; Preferably, the sintering time is 5 min-10 min. 10. The transparent high-temperature sintered silver paste prepared according to the transparent high-temperature sintered silver paste according to any one of claims 1-4 or the preparation method described in any one of claims 5-7 is used on PCB boards, microelectronics or solar panels in the application.