An electret master batch applied to PP meltblown cloth

Medical masks (three-layer structure in total), as shown in the picture. Among them, the middle layer of the melt-blown cloth is polypropylene material with electret masterbatch and electret piezoelectric treatment. This layer is the core part. Only after the electret treatment, there is a lot of charge on the melt-blown cloth, which is also charged 0.3 Micron non-oily small particles have a strong adsorption effect, usually more than 95%, and the filtration efficiency of Staphylococcus aureus bacterial aerosol has to be lower than 95%, which is the origin of the concept we usually call N95 masks .

■ Main technical requirements for N95 masks

The national YY 0469-2004 "Technical Requirements for Medical Surgical Masks" standard stipulates:

1: Filtration efficiency: under the condition of air flow (30±2) L/min, the filtration efficiency of sodium chloride aerosol with aerodynamic median diameter (0.24±0.06) μm is not less than 30%;
2: Bacterial filtration efficiency: Under the specified conditions, the filtration efficiency of Staphylococcus aureus aerosol with an average particle diameter of (3±0.3) μm is not less than 95%;
3: Breathing resistance: Under the condition of filtration efficiency and flow rate, the inspiratory resistance does not exceed 49Pa, and the expiratory resistance does not exceed 29.4Pa.
Because the charged melt-blown cloth can more effectively filter the bacterial aerosol of Staphylococcus aureus in the droplets, it is necessary to use a static-charged filter to meet the bacterial filtration efficiency greater than 95% and the respiratory resistance not to exceed 49Pa at the same time. Meltblown cloth, at the same time, it can reduce the resistance of non-woven products under the same fiber fineness and gram weight.