Since the outbreak of Coronavirus Disease (COVID-19)

masks can effectively prevent the spread of virus

which is not only a crucial weapon for preventing the virus

but also an indispensable anti-epidemic material in the process of resuming production. On the premise of ensuring safety

the reuse of masks is of great significance to alleviate the contradiction between supply and demand in the market and avoid the waste of resources. Commonly used disposable nonwoven fabric masks are divided into inner

middle and outer layers. The middle layer is an isolation filter layer

which is a key layer for protection. The material used is ultra-fine polypropylene melt-blown nonwovens (Abbreviated as PP film). In the production process

the PP film usually needs to be charged by corona polarized charging

so as to use static electricity to adsorb viruses and virus-containing particles to achieve a protective effect. And the more stable the charge

the stronger the adsorption capacity

the higher the blocking efficiency. Therefore

research on the mechanism of blocking and charge stability is the key to reusable masks. This paper systematically summarizes the effects of electret process

charge decay process and the structure of PP on the surface charge

mainly including charging voltage

charging temperature and time

storage environment

PP crystal structure and fiber structure

etc

aiming to provide guidance for the design and production of reusable masks.