Low-temperature hot-pressing conductive silver paste, element and equipment

Abstract

The invention discloses a low-temperature hot-pressing conductive silver paste, an element and equipment, the conductive silver paste comprises the following raw materials: 50-80 parts of silver powder, 8-15 parts of low-temperature curing resin, 2-5 parts of an auxiliary agent and 0-30 parts of a solvent, and the Tg temperature of the low-temperature curing resin is not higher than 20 DEG C. The low-Tg resin is used, the resin has good flexibility, the performance requirement of flexible printing electronics on materials is well met, the silver paste adopts a hot-pressing process, long-time high-temperature baking is not needed, the silver paste can be rapidly completed under the low-temperature condition, and lower energy consumption and higher production efficiency are achieved.

Description

Technical Field

[0001] The invention belongs to the field of electronic technology, and in particular relates to a low-temperature hot-pressed conductive silver paste, a component and a device. Background Art

[0002] Flexible printed electronics is a technology that manufactures functional devices and circuits on the same flexible substrate by printing, eliminating the subsequent subtractive molding and SMT processes. Flexible printed electronics technology has been favored by the electronics industry due to its characteristics and advantages such as direct printing, short design to product cycle, fewer process steps and flexible material selection. Therefore, it has broad application prospects in the fields of information, energy, medical care, national defense, etc., such as flexible electronic displays, sensors, organic light-emitting diodes, printed RFID, thin-film solar panels, electronic newspapers, electronic skin / artificial muscles, etc.

[0003] With the development of intelligent vehicles and wearable electronics, flexible printed electronics are rapidly penetrating into the smart car market. Mainly reflected in the application of smart cockpits and smart surfaces, the substrate of flexible printed electronics has also shifted from previous films (PET, PI) to leather and textile fabrics. Because compared with films, the latter have an adjustable three-dimensional porous structure, which can provide high air permeability and water permeability, a large surface area, and strong mechanical softness that can withstand bending, torsion, shearing and stretching, and better comfort. However, these materials cannot withstand high temperatures, and the rough surface and ink diffusion between fibers in 3D textile structures make direct printing on their surfaces very challenging, making it difficult to achieve high conductivity and reliable printed circuit construction.

[0004] Therefore, in view of the above technical problems, it is necessary to provide a low-temperature hot-pressed conductive silver paste, components and equipment.

[0005] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention and should not be regarded as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the invention

[0006] The object of the present invention is to provide a low-temperature hot-pressed conductive silver paste, component and equipment.

[0007] In order to achieve the above object, a technical solution provided by a specific embodiment of the present invention is as follows:

[0008] The low-temperature hot-pressed conductive silver paste comprises raw materials including: 50-80 parts of silver powder, 8-15 parts of low-temperature curing resin, 2-5 parts of auxiliary agent and 0-30 parts of solvent, wherein the Tg temperature of the low-temperature curing resin is not higher than 20°C.

[0009] In one or more embodiments of the present invention, the silver powder is selected from flake powder, spherical powder, and spherical powder.

[0010] In one or more embodiments of the present invention, the average particle size of the flake powder in the silver powder is 2-4 μm, and the tap density is 3-5 g / cm 3 Preferably, the average particle size of the flake powder is 2 μm and the tap density is 3.5 g / cm 3 .

[0011] In one or more embodiments of the present invention, the average particle size of the spherical powder or spherical powder in the silver powder is 400-600 nm, and the tap density is 4-6 g / cm 3 Preferably, the average particle size of the spherical powder or spherical powder is 500nm and the tap density is 5g / cm 3 .

[0012] In one or more embodiments of the present invention, the silver powder is a mixture of at least one of flake powder and spherical powder or spherical powder. The flake silver powder can form more contact sites, and the spherical powder or spherical powder can fill the gaps formed by the accumulation of flake powder, so that the entire conductive filler forms a more compact structure, thereby increasing the conductive performance.

[0013] In one or more embodiments of the present invention, the proportion of flaky powder in the mixture is wt%: 37-100%.

[0014] In one or more embodiments of the present invention, the low temperature curing resin is selected from: polyurethane, polyester, fluororubber, silicone rubber, acrylic acid, epoxy resin.

[0015] In one or more embodiments of the present invention, the auxiliary agent is selected from a curing agent, a dispersant, and a leveling agent.

[0016] In one or more embodiments of the present invention, the curing agent is selected from at least one of blocked isocyanate curing agent, phthalate, silane coupling agent, dicyandiamide, modified dicyandiamide, imidazole, modified imidazole, acid anhydride and amino resin.

[0017] In one or more embodiments of the present invention, the dispersant is selected from BYK-106, BYK-111, BYK-2013, BYK-163, UNIQ 9350, UNIQ 9520, UNIQ 9319, and NOF AD-374M.

[0018] In one or more embodiments of the present invention, the leveling agent is one of silicone oil, acrylates, and fluorocarbon compounds.

[0019] In one or more embodiments of the present invention, no solvent may be added. If a solvent is needed, the solvent is one or more of butyl acetate, butanone, ethylene glycol butyl ether acetate, ethylene glycol butyl ether acetate, and DBE.

[0020] In one or more embodiments of the present invention, the preparation method of the conductive silver paste includes the following steps: first, the organic resin and the organic solvent are fully stirred until the resin is completely dissolved, the corresponding additives are added and stirred evenly to obtain an organic carrier, and then the silver powder is fully ground, added to the above-mentioned organic carrier, and dispersed and mixed evenly to obtain a low-temperature hot-pressed conductive silver paste.

[0021] In one or more embodiments of the present invention, the conductive silver paste can be used in a transfer manner. First, the circuit is printed on a release film. After short-term baking at low temperature, the solvent in the silver paste is removed. Then the circuit is peeled off and transferred to a flexible substrate with a rough surface. By low-temperature hot pressing, when the temperature is higher than the Tg of the resin, the resin itself will soften and become fluid. Under the action of pressure, it can penetrate into the pores of the flexible substrate with a rough surface. This can not only ensure the firm bonding of the silver paste to the flexible substrate, but also form a close contact between the silver fillers, thereby exhibiting good conductivity.

[0022] In one or more embodiments of the present invention, the electronic component includes a conductive layer, and the conductive layer is formed by low-temperature hot pressing conductive silver paste. The electronic component can be, for example, a printed circuit board.

[0023] In one or more embodiments of the present invention, the electronic device includes a device body and electronic components cooperatively arranged on the device body. The electronic device may include, for example, flexible electronic displays, sensors, organic light emitting diodes, printed RFID, thin-film solar panels, electronic newspapers, electronic skin / artificial muscles, and complete machines using them as components.

[0024] Compared with the prior art, the low-temperature hot-pressing conductive silver paste, components and equipment of the present invention have simple formulas and process processes; a low-Tg resin is used, and the resin itself has good flexibility, which well meets the performance requirements of flexible printed electronics for materials; when the silver paste is used to prepare printed circuits, there is no need for long-term high-temperature baking, and only needs to be hot-pressed when the temperature is higher than the Tg temperature to make the silver paste quickly solidify at a lower temperature, thereby reducing energy consumption and effectively improving production efficiency; the use of a transfer printing process can well solve the problem of preparing printed circuits with excellent performance on flexible substrates with high surface roughness. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions 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 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 should fall within the scope of protection of the present invention.

[0026] Group 1

[0027] The components and contents in each example in this group are shown in Table 1.

[0028] Table 1 Composition / content of each embodiment (weight unit: part)

[0029]

[0030]

[0031] The average particle size of the flake powder in the above table is 2 μm, and the tap density is 3.5 g / cm 3 The average particle size of the spherical powder is 500nm and the tap density is 5g / cm 3 .

[0032] The preparation method of low temperature hot pressing conductive silver paste comprises the following steps:

[0033] S1: Weigh the polymer resin and the solvent according to the corresponding ratio, add them into a stirring container in sequence, stir at high speed until the resin is completely dissolved, and leave it for more than 24 hours to obtain an organic carrier.

[0034] S2: Grind the silver powder thoroughly and mix it evenly, add it together with the additives into the organic carrier obtained in S1, continue stirring and dispersing, and obtain the initial product of conductive silver paste.

[0035] S3: The primary conductive silver paste obtained in S2 is transferred to a three-roll grinder, and repeatedly ground until the particle size measured by a fineness detector is 5-10 μm, thereby obtaining a low-temperature silver paste.

[0036] The silver paste prepared in the above embodiment and the silver paste in comparative example 2 (SAP-D001 Yantai Xi'erde) were printed on a release film, and after baking at 80°C for 5 minutes, the solvent in the silver paste was removed, and then the circuit was transferred to leather or textile fabrics, and the printed circuit was combined with the substrate by hot pressing. The hot pressing time was 10 minutes, and the hot pressing temperature was determined according to the temperature tolerance of the substrate. The release film was then removed to complete the preparation of the printed circuit, and then its performance parameters were tested. As can be seen from Table 2, compared with the comparative example, the silver paste prepared using the low Tg resin in the embodiment showed better conductivity and adhesion under low temperature conditions.

[0037] Table 2 Silver paste curing temperature and performance parameters after curing

[0038]

[0039]

[0040] Group 2

[0041] The difference between this group of embodiments and the first group of embodiments is that the average particle size of the flake powder is 3 μm and the tap density is 3 g / cm 3 The average particle size of the spherical powder is 400nm and the tap density is 6g / cm 3 .

[0042] Under the same conditions as the group:

[0043] Table 3 Silver paste curing temperature and performance parameters after curing

[0044]

[0045] Group 3

[0046] The difference between this group of embodiments and the first group of embodiments is that the average particle size of the flake powder is 4 μm and the tap density is 5 g / cm 3 The average particle size of spherical powder or spherical powder is 600nm, and the tap density is 4g / cm 3 .

[0047] Under the same conditions as the group:

[0048] Table 4 Silver paste curing temperature and performance parameters after curing

[0049]

[0050]

[0051] Group 4

[0052] The difference between this group of embodiments and embodiment 4 is only as shown in Table 5.

[0053] Table 5 Composition / content of each embodiment (weight unit: part)

[0054]

[0055] Under the same conditions as the group:

[0056] Table 6 Silver paste curing temperature and performance parameters after curing

[0057]

[0058]

[0059] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

[0060] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A low-temperature hot-pressed conductive silver paste, the raw materials of which include: 50-80 parts of silver powder, 8-15 parts of low temperature curing resin, 2-5 parts of auxiliary agent and 0-30 parts of solvent, wherein the Tg temperature of the low temperature curing resin is not higher than 20°C.

2. The low temperature hot pressing conductive silver paste according to claim 1, characterized in that: The silver powder is selected from flake powder, spherical powder and spherical powder.

3. The low temperature hot pressing conductive silver paste according to claim 2, characterized in that: The average particle size of the flaky powder in the silver powder is 2-4 μm, and the tap density is 3-5 g / cm 3 .

4. The low temperature hot pressing conductive silver paste according to claim 2, characterized in that: The average particle size of the spherical powder or spherical powder in the silver powder is 400-600nm, and the tap density is 4-6g / cm 3 .

5. The low-temperature hot-pressed conductive silver paste according to any one of claims 2 to 4, characterized in that: The silver powder is a mixture of at least one of flaky powder and spherical powder or spherical powder.

6. The low temperature hot pressing conductive silver paste according to claim 5, characterized in that: The proportion of the flaky powder in the mixture is wt%: 37-100%.

7. The low temperature hot pressing conductive silver paste according to claim 1, characterized in that: The low temperature curing resin is selected from the group consisting of polyurethane, polyester, fluororubber, silicone rubber, acrylic acid, and epoxy resin.

8. The low temperature hot pressing conductive silver paste according to claim 1, characterized in that: The auxiliary agent is selected from a curing agent, a dispersant, and a leveling agent.

9. An electronic component comprising a conductive layer, wherein the conductive layer is formed by the low-temperature hot-pressed conductive silver paste according to any one of claims 1 to 8.

10. An electronic device comprising a device body and the electronic component according to claim 9 cooperatively provided to the device body.

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