Advantages, disadvantages and differences of various potting compound

The potting compound is liquid before uncured and has fluidity. The viscosity of the glue differs depending on the material, performance and production process of the product. It can be used after it is fully cured. After curing, it can be waterproof, moisture-proof, dust-proof, insulating, heat-conductive, confidential, anti-corrosive, temperature-resistant and shock-proof. At present, there are many types of electronic potting and sealing glues on the market. From the material types, there are mainly three types, which are epoxy resin potting glue, silicone potting glue and polyurethane potting glue. The selection of potting glue will directly affect the precision and timeliness of the operation of electronic products. How to choose the potting glue suitable for enterprise products in many kinds of potting glues becomes a technical difficulty. The following is a brief introduction of the advantages and disadvantages of these three types of potting glue and the main uses on the market.

Firstly: Epoxy Resin

Advantages: Epoxy potting is mostly hard, and there are very few modified epoxy resins. The material has the great advantage of good adhesion to the material and good insulation, and the cured product has good acid and alkali resistance. Epoxy resin is generally resistant to temperature of 100 ° C. The material can be used as a transparent material and has good light transmittance. The price is relatively cheap.

Disadvantages: weak resistance to cold and heat, cracks easily occur after thermal shock, resulting in water vapor infiltrating into the electronic components from the cracks, poor moisture resistance; high hardness and brittleness after solidification, high mechanical stress Easy to pull the electronic components; after the epoxy resin is potted and cured, it cannot be opened due to the high hardness, so the product is a "lifetime" product, and the replacement of components cannot be realized; the transparent epoxy resin material generally has poor weather resistance. It is prone to yellowing under light or high temperature conditions.

Applications: Generally used for potting of non-precision electronic devices such as LEDs, transformers, regulators, industrial electronics, relays, controllers, power modules, etc.

Secondly: Polyurethane

Advantages: Polyurethane potting compound has excellent low temperature resistance, the material is slightly soft, and has good adhesion to general potting materials. The bonding force is between epoxy resin and silicone. It has good waterproof, moistureproof and insulation properties.

Disadvantages: Poor high temperature resistance and easy foaming, vacuum defoaming must be used; after curing, the surface of the colloid is not smooth and the toughness is poor, anti-aging ability, anti-shock and ultraviolet rays are weak, and the colloid is easily discolored.

Scope of application: Generally used for potting of electronic components with low heat generation. Transformers, chokes, converters, capacitors, coils, inductors, varistors, linear engines, stationary rotors, circuit boards, LEDs, pumps, etc.

Thirdly: Silicone
Advantages: The silicone potting compound has a soft material after curing. It has two forms of solid rubber and silicone gel, which can eliminate most mechanical stress and provide shock absorption protection. It has stable physicochemical properties, good resistance to high and low temperature, and can work in the range of -50~200 °C for a long time. Excellent weather resistance, it can still play a good protection role for more than 20 years outdoors, and it is not easy to yellow. It has excellent electrical and insulating properties, effectively improves the insulation between internal components and lines after potting, and improves the stability of the use of electronic components. With the ability to repair, the sealed components can be quickly and easily removed for repair and replacement.

Disadvantages: The bonding performance is not so strong.

Applications: Suitable for potting all kinds of work in harsh environments as well as high-end precision/sensitive electronic devices. Such as LED, display, photovoltaic materials, diodes, semiconductor devices, relays, sensors, car stabilizers, automotive ECUs, etc., mainly for insulation, moisture, dust, shock absorption.

With the large-scale development of electronic technology, due to its many excellent properties, silicone rubber will undoubtedly become a better potting material for potentiation of sensitive circuits and electronic devices. Mingcheng Group Limited has been engaged in the research and development of silicone for more than 15 years. Currenty, it has successfully developed various types of formable silicone rubber and silicone gel products, which are suitable for all kinds of sensitive circuits, precision electrical appliances and electronic products under special conditions. Product potting. At the same time, the company can customize the suitable silicone potting glue according to customer needs.