Introduction to simple circuit board protection packaging In order to seal a certain part of the circuit board or a smaller circuit board to prevent water vapor and foreign substances from entering and affecting the performance of the circuit, many electronic enthusiasts use wax or asphalt as sealing materials to protect the circuit. In fact, wax and asphalt as encapsulation materials are not good and have many disadvantages. However, the effect of "soft encapsulation" is much better. Currently, the best "soft encapsulation" materials commonly used include epoxy resin, polysulfide, polyurethane, and organic silicon, etc. four types of encapsulation materials.

The expert explained that "soft packaging" means that it does not require the use of a packaging shell to install and protect the integrated circuit chip. Instead, it uses printed circuit boards made of organic materials or ceramic metallized wiring substrates to directly place the chip at the predetermined position. Then, metal wires are used to connect each output and input terminal of the chip to the printed lines or metallized wiring. After that, soft sealing materials are used to cover the chip, metal wires, and all the solder joints to achieve the purpose of chip assembly. "Soft packaging" has been widely applied in some electronic watch circuits, electronic music circuits, and amateur-made electronic circuits. Due to its simple packaging method and low cost, it is also called simple packaging or C·O·B packaging.

The epoxy resin packaging material has excellent insulation, chemical resistance, adhesion and other properties. It has a low curing shrinkage rate (2%). It is the best among "soft packaging" materials. Its typical formulation actually consists of epoxy resin and polyamide mixed glue: 100 parts of 618 (or 828) epoxy resin, 50-70 parts of 650 (or 651) polyamide, 2-5 parts of EMI-2,4 diethyl tetramethylimidazole, 20-40 parts of 95% AL2O3 ceramic powder (400 mesh), 5-15 parts of white carbon black, 20-40 parts of ZnO, 5 parts of TiO2, 1-2 parts of Cr2O3 (dye). When using, it is first thoroughly mixed, applied to the area to be sealed to form a hemispherical shape (do not cause bubbles), then dried at room temperature for 2-4 hours, and then treated at a temperature of 60-150°C for 20-30 minutes to complete. The raw materials in the formula can be purchased fully at the chemical store, and there are also specialized soft packaging resin glues on the market (commonly known as black glue), divided into transparent and opaque types, but they require a several-hour high-temperature curing process.