What we should know about the material of N95 and KN95 masks?
The critical material to make qualified masks is PP Meltblown fabric. Let's talk about this.
Melt blowing Technology
Melt blowing is a technique used for the manufacture of thin sheets of nonwoven fibers. It is a method by which polymer met is extruded out through tiny nozzles and subjected to high-speed blowing gas. Due to presence of gas, the extruded polymer forms a nonwoven polymer sheet.
Different polymers are used as raw materials in the process of melt blowing. The process starts with a polymer resin and ends with a finished, self-bonded fabric with superior properties.
Some of the commonly used polymers include polypropylene, polyesters, poly-amides, and polystyrene. The fibers obtained are ultra-fine in nature compared to the fibers obtained by any other manufacturing process such as spun bound. The filaments obtained by this technique are generally of the size of 2–5 microns. However, by modification, the size can be reduced up to 0.5 micron even.
Due to the fine size of filaments, the nonwoven fabric obtained is soft and durable. Meltblown fabrics are known to have high insulating properties and good barrier properties, which makes them useful in a variety of applications.
Polypropylene meltblown nonwoven is the essential material to make mask. It can meet the standard from BFE95% to BFE 99%. It can also be good material of isolation/ surgical gowns, protection covers/sheets.
It is opacity, low abrasion resistance, no stimulation smell. Its dense microfiber structure (up to 70%) acts as an excellent barrier against particles, bacteria, and other contaminating agents, combining high filtration efficiency with excellent air permeability. And it also can be used for the liquid barrier, absorption products for oil.
Masks must achieve their separation performance with the lowest possible pressure drop – in other words, filter resistance. Pressure drop is one of the most important quality features of masks: the lower the pressure drop, the more energy efficient.
Even mask with Polypropylene meltblown are often not sufficient to filter the finest particles from air or liquid flows. For this reason, the nonwovens are treated online or offline; for example, they are electrostatically charged to increase their filter performance.