Performance characteristics of room temperature curing epoxy potting compound

The difference between silicone and epoxy

Room temperature vulcanized silicone rubber or silicone gel is used for potting of electronic and electrical components, which can play the role of moisture, dust, corrosion and shock resistance, and improve the performance and stability of the parameters, and it is a liquid before vulcanization, which is convenient Perfusion, easy to use. When using silicone gel for potting, it does not emit low, no stress shrinkage, can be deeply vulcanized, without any corrosion, transparent silicone becomes a transparent elastomer after vulcanization, and the components encapsulated in the glue layer are clearly visible and can be used Acupuncture to measure component parameters one by one to facilitate inspection and repair. There are also opaque grays or blacks, with different colors in different applications. The foamed silicone rubber vulcanized at room temperature is used in the magnetic core board of the memory in the electronic computer. It has fully met the requirements after many tests such as vibration, shock, cold and hot alternating. Addition molding room temperature vulcanized silicone rubber based on the flame-retardant potting glue used for TV high-pressure cap and high-voltage cable sheathing and other products are very effective in molding. For the use of single-component room-temperature vulcanized silicone rubber as the surface coating material, when there is no need for hermetic packaging or inconvenience for impregnation and potting. Generally, the surface coating of electronic components is made of room temperature vulcanized silicone rubber, and the inner coating is made with an addition silicone gel. In recent years, glass resin coated electronic appliances and instrument components have been widely used.

Potting is an important application area of ​​epoxy resin. It has been widely used in the manufacture of electronic devices and is an indispensable important insulating material in the electronics industry. Potting is to fill a liquid epoxy resin compound into a device equipped with electronic components and wires by mechanical or manual means, and cure it under normal temperature or heating conditions to become a thermosetting high-insulation material with excellent performance. Its functions are: to strengthen the integrity of electronic devices and improve the resistance to external shocks and vibrations; to improve the insulation of internal components and wires, which is conducive to the miniaturization and weight reduction of devices; Moisture resistance. Epoxy potting compound has a wide range of applications, technical requirements vary widely, and there are many varieties. From curing conditions, there are two types of room temperature curing and heating curing. From the dosage form, there are two types of two-component and one-component. Multi-component dosage forms are rare as commodities due to inconvenient use.

Normal temperature curing epoxy potting compound is generally two-component, which can be cured without heating after potting. It has low requirements on equipment and is easy to use. The disadvantage is that the compound has high viscosity, poor infiltration, short application period, it is difficult to realize automatic production, and the heat resistance and electrical properties of the cured product are not very high. Generally used for potting low-voltage electronic devices or not suitable for heating and curing.

Heat curing two-component epoxy encapsulant is the most widely used and most versatile product. It is characterized by low operating viscosity of the compound, good manufacturability, long application period, good infiltration, and excellent comprehensive performance of the cured product. It is suitable for the use of single-component epoxy potting compound in the automatic production line of high-voltage electronic devices. It has been developed abroad in recent years. New varieties require heating and curing. Compared with the two-component heating and curing potting compound, the outstanding advantages are that the required potting equipment is simple, easy to use, and the quality of the potting compound is less dependent on the equipment and process. The shortcomings are higher cost and strict storage requirements for materials. The epoxy encapsulants used should meet the following requirements:

1. Good performance, long application period, suitable for large-volume automatic production line operations.

2. The viscosity is small, the infiltration is strong, can fill the components and the line.

3. During the potting and curing process, the powder components such as fillers have a small settling and do not delaminate.