There are black impurities in the filter screen of meltblown cloth equipment every time it is replaced.

Decomposition of PP material. Meltblown cloth is the core material of mask. There are black impurities in the filter screen because when processing melt-blown PP materials, PP is a high polymer, which will decompose into carbides at high temperature for a long time, while carbon is black, so some black impurities are formed. PP plastic raw material, chemical name polypropylene, is superior to low-pressure polyethylene in density, strength, rigidity, hardness and heat resistance. Can be used around 100 degrees. Good electrical performance, high-frequency insulation, not affected by humidity, but brittle, not wear-resistant, easy to age at low temperature.