Research on LED Epoxy Resin Packaging Materials

As a light-emitting device with low power, long service life and low energy loss, light-emitting diodes have been popular in China for nearly 20 years. Due to their special performance advantages, they are gradually replacing the original light-emitting devices and are used in various corners of industry and civil use. Especially with the shortage of human energy, the market prospect is very promising.

        In recent years, LED has been applied more and more widely in urban lighting projects, industrial and civil construction industries. It is reported that civil LED chips have been successfully developed abroad. It is foreseeable that in the near future, your home decoration will also be illuminated by LEDs .

　　Overview

　　At present, there are more and more domestic LED manufacturers, and the mid-range products account for nearly 50% of the market, while about 40% of the high-end market is still occupied by foreign companies, mainly from Hong Kong and Taiwan. It can be seen that the market prospect of LED is still very promising. This also provides development opportunities for domestic manufacturers of supporting materials, such as chips, epoxy resin packaging materials, mold strips (mold particles), brackets, etc.

　　At present, about 50% of the epoxy resin encapsulation market is imported, mainly in the high-end market. Companies like Haisuo, Chuanyu, Lishang, EPFINE, etc. basically occupy the high-end market. Shaohui Group was the first domestic company to produce LED epoxy resin encapsulation materials. In recent years, manufacturers such as Shunde ACR, Changsha Bluestar, and Jiangyin Tianxing have emerged. However, domestic companies basically maintain the production of lower-grade encapsulation materials, and the output is also small. There is still a long way to go for high-end products. The market welcomes strong domestic companies and research institutions to develop and produce high-end epoxy resin materials.

　　The research results of the packaging materials in this article are only for reference by peers. We hope that it can serve as a starting point for further research and contribute to the development of domestic LEDs.

　　1. Material selection of main agent

　　1 Epoxy resin: transparent, colorless, low in impurity content and low in viscosity. Dow Chemical's 331J, Nan Ya's 127, Mitsui's 139, Dainippon Ink's EP4000 can all be used. Hongchang's 127 can also be used in the mid- and low-end markets.

　　2. Reactive diluent: Generally, it is better to use alicyclic difunctional reactive diluent, but it is basically not produced in China, or the unit price is too high. In special occasions, AGE from Nan Ya can be used instead, but AGE affects the strength after curing and the cross-linking degree is not enough. If the viscosity of the resin is low, you can choose not to add diluent.

　　3 Defoamer: The principle is good compatibility, good defoaming performance, and no low boiling point solvent. BYK-A530, BYK-066, BYK-141, Deqian 6500, etc. can be selected.

　　4. Toner: Generally, 20% of transparent oil-compatible dye is added to 80% of the main epoxy resin, and then heated and stirred to dissolve. It can be added in small amounts to eliminate the yellowish color caused by the addition of resin and other materials, and ensure the purity of the color after curing. Pay attention to the selection of transparent oil-compatible dye, which must have a temperature resistance of at least 150-180 degrees to prevent discoloration during heating and curing. For example, Bayer PEG-400.

　　5. Release agent: The principle is to have good release effect, good compatibility and light color. For example, FINT-900 from Guangzhou Colas Company (BYK agent) and TMA release agent from Wuxi Sanshan Electronic Materials Factory can be used. The amount of addition varies depending on the material. The release agent can be added to the main agent or the curing agent.

　　2. Material selection of curing agent

　　1-Methylhexahydrophthalic anhydride is produced in China by Jiaxing Alpha Fine Chemicals and Henan Puyang Huicheng Fine Chemicals, but the free anhydride content is generally high and it is only used in the production of medium and low-end products. Products from Italy's LONZA company are used for higher requirements.

　　2. Accelerators Many domestic manufacturers have wasted a lot of time in this regard. In fact, it is still feasible to use quaternary ammonium salts in the acid anhydride system, such as tetrabutylammonium bromide and tetrahexylammonium bromide from Zhejiang Jintan Chemical Research Institute. However, the latter may not be very compatible and can be diluted with alcohols such as benzyl alcohol and glycerol before use. However, it will affect the strength. Therefore, the former is better.

　　3 Antioxidants are mainly used to prevent anhydride from being oxidized during high temperature curing. They require good compatibility and light color. General 264 can also be used when the requirements are not high.

　　3. Recipe examples: ( The following recipe is for reference only, I do not assume any responsibility)

　　Main agent: R-13996.6 Curing agent: Methyl hexahydrophthalic anhydride 95.54

　　AGE3 Tetrabutylammonium Bromide 1.4

　　Blue dye paste 0.3264 Antioxidant 1.5

　　BYK-A5300.05 glycerol 1.5

　　FIN release agent 0.05 blue dye paste 0.01

　　Total 100 copies Total 100 copies

　　Ratio: 100/100

　　Four production processes

　　Since it does not involve synthetic reactions, the production process is relatively simple. Generally, it is heated to below 80 degrees, stirred for about an hour, cooled and discharged. However, attention should be paid to the order of adding materials, such as first dissolving the solid material with the liquid material sparsely and then adding it in sequence.