1、 Epoxy resin
Advantages: Epoxy resin sealant is mostly hard, and there are also a few modified epoxy resins that are slightly soft. The major advantages of this material are its good adhesion and insulation properties, as well as its excellent acid and alkali resistance in cured materials. Epoxy resin generally has a temperature resistance of 100 ℃. The material can be used as a transparent material with good transparency. The price is relatively cheap.
Disadvantages: Weak resistance to cold and hot changes, prone to cracking when subjected to cold and hot impacts, resulting in water vapor seeping into electronic components from the cracks and poor moisture resistance; After solidification, the colloid has high hardness and brittleness, and high mechanical stress can easily strain electronic components; Once epoxy resin is filled and cured, it cannot be opened due to its high hardness, so the product is a "lifetime" product and cannot be replaced with electronic components; Transparent epoxy resin materials generally have poor weather resistance and are prone to yellowing under light or high temperature conditions.
Application scope: Generally used for potting non precision electronic devices such as LEDs, transformers, regulators, industrial electronics, relays, controllers, power modules, etc.
2、 Polyurethane
Advantages: Polyurethane sealant has excellent low temperature resistance, slightly soft material, and good adhesion to general sealant materials, with a bonding strength between epoxy resin and silicone. Has good waterproof, moisture-proof, and insulating properties.
Disadvantages: Poor high temperature resistance and easy foaming, requiring vacuum defoaming; After curing, the colloid surface is not smooth and has poor toughness. The anti-aging ability, seismic resistance and ultraviolet radiation are weak, and the colloid is easy to change color.
Application scope: Generally used for sealing electronic components with low heat generation. Transformers, anti current coils, converters, capacitors, coils, inductors, variable resistors, linear engines, fixed rotors, circuit boards, LEDs, pumps, etc.
With the rapid development of electronic technology, organic silicone rubber will undoubtedly become the preferred sealing material for sensitive circuits and electronic devices due to its excellent properties.