Electret is the necessary guarantee of the efficiency of the mask filtration. If the proper electret is not used, the static electricity on the melt blown cloth is easy to escape. If the electrode is not applied, the mask may meet the N95 standard when it is newly made, but the filtering efficiency will become very low in a few months.
Electret materials are widely used in the field of high efficiency and low resistance air filter materials. Electret filtering materials require high density of stored charge, long life and high stability. The raw materials used as electrets need excellent dielectric properties, such as high volume resistance and surface resistance, high dielectric breakdown strength, low moisture absorption and air permeability.