Conductive adhesive for LED encapsulation and preparation method thereof

A technology of LED packaging and conductive adhesive, which is applied in the direction of circuits, adhesives, electrical components, etc., can solve the problem that the conductive adhesive does not adapt to the rapidly growing demand of the LED industry, and achieve the goals of accelerating curing speed, improving thermal conductivity, and optimizing electrical conductivity Effect

Inactive Publication Date: 2018-05-08

苏州亿沃自动化技术有限公司

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AI-Extracted Technical Summary

Problems solved by technology

At the same time, the currently used conductive adhesives that require low-temperature...

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Abstract

The invention discloses a conductive adhesive for LED encapsulation and a preparation method thereof. The conductive adhesive for LED encapsulation comprises 13-16.5 wt.% of resin system, 0.9-1.4 wt.%of dicyandiamide curing system, 0.1-0.35 wt.% of short chain dibasic acid, 65-72 wt.% of silver powder, 5-8 wt.% of low melting point alloy powder, 1-1.5 wt.% of graphene powder, and 4.5-10 wt. % ofother additives. According to the conductive adhesive for LED encapsulation, by adopting dicyandiamide, the highest peak of the curing of the resin system is shifted from a low temperature area to accelerate the curing speed of the resin system, the short chain dibasic acid can remove some organic insulating lubricants on the surface of the silver powder, and the phenomenon of silver powder agglomeration caused by fast removal of the insulating lubricants does not occur, so that conductive properties of the conductive adhesive are optimized, and graphene which is added can at least partially adhere to the surface of the alloy powder to build heat conduction paths of a plurality of heat conduction mediums to improve thermal conductivity of the LED conductive adhesive.

Application Domain

Non-macromolecular adhesive additivesEpoxynovolac adhesives +1

Technology Topic

Thermal conductivityDibasic acid +6

Examples

Experimental program(6)

Example Embodiment

[0021] An embodiment of the present invention provides a conductive adhesive for LED packaging and a preparation method thereof, which have excellent electrical conductivity and extremely high shear strength. The conductive adhesive for LED packaging includes:

[0022] 13~16.5wt.% resin system, 0.9~1.4wt.% dicyandiamide curing system, 0.1~0.35wt.% short chain dibasic acid, 65~72wt.% silver powder, 5~8wt.% low melting point alloy powder, 1-1.5wt.% graphene powder, and 4.5-10wt.% other additives.

[0023] In one embodiment, the resin system includes one or a combination of bisphenol A type epoxy resin, phenolic epoxy resin, and bisphenol F type resin.

[0024] In one embodiment, the content of the resin system is preferably 16 wt.%.

[0025] In one embodiment, the content of the dicyandiamide curing system is preferably 1.3 wt.%.

[0026] In one embodiment, the short-chain dibasic acid includes one or a combination of succinic acid, glutaric acid, and adipic acid.

[0027] In one embodiment, the content of the short-chain dibasic acid is preferably 0.35 wt.%.

[0028] In one embodiment, the average particle size of the silver powder is 6-8 μm, preferably 6.5 μm; the content of the silver powder is preferably 70 wt.%.

[0029] In one embodiment, the content of the graphene powder is preferably 1.25 wt.%.

[0030] In one embodiment, the other additives include defoaming agents, dispersants, and coupling agents; and/or the low melting point alloy powder includes one or more of tin-bismuth alloy powder and tin-bismuth alloy powder combination of species.

[0031] The present invention also provides the above preparation method of the conductive adhesive for LED encapsulation, the method comprising:

[0032] 65-72wt.% silver powder, 5-8wt.% low-melting alloy powder, and 1-1.5wt.% graphene powder are mixed uniformly, ground and dried, and then calcined at 650-700°C for 2-3 hours in a reducing atmosphere, Obtain the alloy powder mixed with graphene powder;

[0033] Take 13-16.5wt.% resin, 0.9-1.4wt.% dicyandiamide, 0.1-0.35wt.% short-chain dibasic acid, and 4.5-10wt.% other additives and mix them evenly, and slowly add the above prepared alloy The powder is stirred, and the foam is removed by vacuum to obtain a conductive adhesive for LED packaging.

Example Embodiment

[0034] Example 1

[0035] 65wt.% silver powder, 8wt.% tin-bismuth alloy powder, and 1wt.% graphene powder are mixed uniformly, ground and dried, and then calcined at 650-700 °C for 2 hours in a reducing atmosphere to obtain an alloy mixed with graphene powder powder;

[0036] Take 16.5wt.% bisphenol A epoxy resin, 1.4wt.% dicyandiamide, 0.35wt.% succinic acid, and 3.5wt.% defoamer, dispersant, and coupling agent, mix well, add slowly The alloy powder prepared above is stirred, and the bubbles are removed by vacuum to obtain a conductive adhesive for LED packaging.

[0037] After testing, the conductive adhesive of this embodiment can be stored at room temperature for 3 months, cured at 185 ° C for 55 minutes, and the resistivity after curing is 1.25*10 -4Ω cm, the thermal conductivity is 10.25W/(m·K), and the shear strength is 18.4MPa.

Example Embodiment

[0038] Example 2

[0039] 70wt.% silver powder, 5wt.% tin-bismuth alloy powder, and 1.5wt.% graphene powder were mixed uniformly, ground and dried, and then calcined at 650-700°C for 2 hours in a reducing atmosphere to obtain a graphene powder mixed with graphene powder. alloy powder;

[0040] Take 15wt.% phenolic epoxy resin, 0.9wt.% dicyandiamide, 0.1wt.% glutaric acid, and 7.5wt.% defoamer, dispersant, and coupling agent and mix them evenly, and slowly add the prepared The alloy powder is stirred, and the bubbles are removed by vacuum to obtain a conductive adhesive for LED packaging.

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PUM

Property	Measurement	Unit
The average particle size	6.0 ~ 8.0	µm
Resistivity	1.25 ~ 10.0	cm·Ω
Thermal conductivity	10.25	W/k/m
tensile		MPa
Particle size		Pa
strength	10

Description & Claims & Application Information

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the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine

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