Application of Thermally Conductive Potting Silicone Rubber in LED Power Supply

[Source: "High-tech LED - Technology and Applications" October issue]

With the development of aviation, aerospace, shipbuilding and electronics, the high performance of potting devices has placed increasing demands on potting materials, exploring new methods for preparing potting materials, and seeking high performance potting. Materials have become an important topic in research in this field. The materials, components, components, etc. used in the use of electronic equipment may be affected by the environment, resulting in reduced reliability of the equipment. In many cases, the individual effects of environmental factors are not obvious. When two or more environmental factors act simultaneously, the combined effect is much more significant. Therefore, it is necessary to implement process protection against the influence of various environments on products, and continuously improve the environmental adaptability of products. Among them, electronic potting is a common means of electronic protection. It is a process of rationally arranging, assembling, connecting, environmentally isolating and protecting the components constituting the electric device according to the specified requirements to prevent moisture, dust and harmful gases. The intrusion of electronic components is to strengthen the integrity of the electronic device, reduce vibration, prevent external damage, and stabilize the parameters of various components.

With the development of science and technology and market demand, higher requirements are placed on the stability of electrical appliances, and the heat dissipation becomes the key to the miniaturization design of the whole machine. The improvement of electrical power requires that the potting material has good heat dissipation and insulation properties. Because if the heat is not transmitted in time, local high temperature is easily formed, which may damage components and components, thereby affecting the reliability of the flow and the normal working cycle. According to relevant data, the reliability of the product can be reduced by 10% for every 2°C increase in temperature of the electronic component; the life of the temperature rise to 50°C is only 1/6 of the temperature rise of 25°C. Silicone rubber is the first choice for power-based potting material based on its excellent physical and chemical properties and process performance. After adding high thermal conductivity filler, it can obtain heat-insulating and potting liquid brick rubber. With the continuous maturity of the process, the heat-conducting liquid brick rubber plays an increasingly important role in the protection of the equipment, especially in the protection of high-voltage and high-power component components.


1. Performance characteristics of thermally conductive potting silicone rubber

Silicone rubber can maintain elasticity at -60~200 °C for a long time. It does not absorb heat, does not release heat during curing, does not shrink after curing, has good adhesion to materials, and has excellent electrical properties and chemical stability. It is water and resistant. Ozone, weather resistance, with its potting LED products can play the role of moisture, corrosion, shock and dust. Stabilizing component parameters, silicone rubber can be divided into single component and two component according to the different components. The most common thermal silicone rubber is composed of two components, components A and B, according to chemical reaction. The mechanism can be divided into two types of silicone rubbers, such as addition molding and condensation. The formed products can be deeply potted and have no low molecular weight during the vulcanization process. The shrinkage rate is low and the adhesion to the component or potting cavity wall is low. . One-component thermal conductive silicone rubber also includes two types of condensation type and addition type. The condensation type product generally has good adhesion to the substrate, but is only suitable for shallow potting, and one-component addition of heat-conductive silicone rubber is generally required. It is stored at low temperature and needs to be heated and vulcanized after filling. The most important feature of thermally conductive potting silicone rubber is that it is repairable. When producing electrical/electronic equipment, it is desirable to recycle used or damaged products. It is difficult or impossible to remove and refill a non-silicone rigid potting/sealing material without causing significant damage to the internal circuitry.

Silicone potting can be used to selectively remove, repair or completely replace and refill the new potting compound at the repaired area. When the silicone elastomer is removed, the undesired material can be simply torn or removed from the area to be repaired using a sharp blade or knife. For the elastomer adhered to the portion, it is preferably removed from the substrate or the circuit by mechanical means such as scraping or rubbing, and silicone oil may be used as an auxiliary. Before refilling the repaired device, sandpaper is used to roughen the surface of the cured potting compound and then wiped with a suitable solvent. This helps to strengthen the bond and combine the repaired material with the existing potting compound. It is not advisable to use silicone primer as the adhesive for the product itself.

Unfinished

For more information, please refer to the October issue of "High-tech LED-Technology and Applications"

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LED Underground Lamp

Product size

LED Underground Lamp

Technical parameters 

Main material

High - pressure cast aluminum, 92% high - light steel screen printing glass

The light colored temperature

Red/Green/Yellow/Amber/Vermilion/Acid blue/3000K/4000K/5000K/6000K

 

Surface treatment

UV  Polyester powder coating

Light distribution device

Reflector lamp cup series:6°

Optical lens series:8°/15°/25°/45°/10×30°/10×60°/20×40°

The light body color

Dark grey

Working voltage

DC24V

Safeguard procedures

Silica gel ring compacted waterproof

way to install

Embedded part

Average lifetime

350mA20000hours,500mA15000hours

rated power

/

Control mode

/

Level of protection

IP65

operating ambient temperature

-25℃~50℃

Working environment humidity

10%~90%






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