Causes and solutions of air bubbles in three-proof coatings painting

The reason why bubbles appear in the three-proof paint is generally because the circuit board is not cleaned and dried, and there is dust and moisture on the circuit board, and so on.

Three-proof paint is a kind of paint with special formula, which is used to protect the circuit board and its related equipment from environmental erosion. Three-proof paint has good high and low temperature resistance; After curing, it becomes a transparent protective film, which has excellent insulation, moisture-proof, leakage-proof, shock-proof, dust-proof, corrosion-proof, aging-proof and corona-proof properties.

In the application of three-proof coatings, the problem of bubbles is often encountered. Generally, it is necessary to consider which process link the bubbles appear in, or whether there are bubbles when spraying directly? Or is there no bubble when spraying, and bubbles appear after heating and curing?

If there are bubbles when the material comes out of the nozzle, factors such as coating process pressure, material viscosity, nozzle model and humidity should be considered. If bubbles appear after passing through the furnace, please carefully adjust the furnace temperature curve and the route of the nozzle. Many engineers in the industry solve this problem by adding thinner to reduce viscosity, which can really improve the bubble problem. However, adding a large amount of diluent will reduce the thickness of cured coating after coating and increase the discharge of organic solvent, which not only wastes diluent, but also is not environmentally friendly. Even after adding a large amount of diluent, some materials will still have tiny bubbles when spraying, and the small bubbles will accumulate into larger bubbles after baking in the furnace. In addition, if it is 100% UV curing three-proof paint, it is inconvenient to add thinner to reduce viscosity and improve bubbles. Sometimes, the coating equipment manufacturer will suggest adding a temperature circulating device to increase the temperature and thus reduce the viscosity. Paint heating device will increase equipment cost and energy consumption.