Properties and Characteristics of Heat Conducting Encapsulated Silicone Rubber

Silicone rubber can keep elasticity at - 60~200 ℃ for a long time. It does not absorb and release heat during curing, and does not shrink after curing. It has good adhesion to materials. It also has excellent electrical performance and chemical stability, water resistance, ozone resistance, and weather resistance. After filling LED products with silicone rubber, it can play the role of moisture prevention, corrosion prevention, shock prevention, and dust prevention. To stabilize element parameters, silicone rubber can be divided into single component and two-component forms according to the different components contained. The most common thermal conductive silicone rubber is two-component, consisting of components A and B, in which, according to the chemical reaction mechanism, it can be divided into two types of silicone rubber: additive type and condensation type. The additive products can be deep encapsulated and there is no low molecular substances produced during the curing process, with low shrinkage and low adhesion to the element or the wall of the potting chamber. Single component thermal conductive silicone rubber also includes condensation type and addition type. Condensation type products generally have good adhesion to the substrate, but are only suitable for shallow encapsulation. Single component addition type thermal conductive silicone rubber generally needs to be stored at a low temperature, and then needs to be heated and vulcanized at a high temperature. The most important feature of thermal conductive potting silicone rubber is that the product is repairable. When producing electrical/electronic equipment, people hope to recycle the discarded or damaged products. It is difficult or impossible to remove and re inject non silicone rigid potting/sealing materials without causing great damage to internal circuits.

The silicone potting adhesive can be conveniently removed, repaired or completely replaced selectively, and new potting adhesive can be poured into the repaired part. When removing the silicone elastomer, you can simply use a sharp blade or knife to tear or remove the unnecessary materials from the area to be repaired. For the elastomer adhered to the part, it is better to remove it from the substrate or circuit by mechanical methods such as scraping or friction, and silicone oil can be used as an auxiliary agent. Before refilling the potting adhesive on the repaired device, the surface of the cured potting adhesive needs to be roughened with sandpaper, and then wiped with appropriate solvent. This is helpful to enhance the adhesive force and integrate the repaired materials with the existing potting and cementation. The silicone primer should not be used as the adhesive of the product itself.