Original title: What materials are N95 mask made of? As of today, the domestic epidemic has come to an urgent moment, in order to prevent the epidemic from continuing to spread, masks have now become a necessary item for human hands. So why can masks stop the spread of the virus? What kind of material is it? We usually say that the mask is a non-woven material, non-woven is relative to textile cloth, that is, non-woven cloth, is composed of directional or random fibers. Specific to the mask, its raw materials are all Polypropylene (PP). Medical masks are generally multi-layer structure, generally referred to as SMS structure. See Figure 1 and Figure 2 for schematic diagrams. Expand the full text The layers of masks we often talk about are not stipulated in the national standard GB/T 32610 for masks. If it is a medical mask, it should be at least three layers,Medical Full Body Coverall, that is, SMS (two layers of S and one layer of M). At present, the highest number of layers in China is five, that is,free shipping disposable coverall, SMMMS (two layers of S and three layers of M). It is not difficult to make masks. More difficult is to make SMMMS cloth, an imported non-woven equipment price is hundreds of millions of yuan, the author has seen the most expensive medical non-woven equipment is 500 million yuan. The S here represents the Spunbond layer, and its fiber diameter is relatively thick, about 20 microns (μm). The main function of the two S spunbond layers is to support the whole non-woven fabric structure, and it does not have much effect on the barrier. The most important thing inside the mask is the barrier layer or meltblown layer M (Meltblown). The fiber diameter of the meltblown layer is relatively thin, about 2 microns (μm), so it is only one tenth of the diameter of the spunbond layer, KN95 Face Mask with Five Layers ,Medical Disposable Coverall, which plays a vital role in preventing bacteria and blood penetration. If the S spunbond layer is too much, the mask will be harder, and if the melt-blown layer M is too much, it will be more difficult to breathe. Therefore, the isolation effect of the mask can be judged from the difficulty of breathing. The more difficult it is to breathe, the better the isolation effect will be. However, if the M layer becomes a film, it will basically not be able to breathe. The virus is blocked, and people are dying. Therefore, this is also a technical problem. In order to better illustrate the problem, we will make a comparison between spunbond layer S fiber, meltblown layer M fiber and hair as follows. 1/3 of the diameter of hair is close to that of spunbond layer fiber, while 1/30 of the diameter of hair is close to that of meltblown layer M fiber. Of course, researchers are still developing thinner fibers to ensure better antibacterial barrier. As mentioned earlier, the thinner the M layer is, the more it can block the entry of bacteria and other tiny particles, such as N95, which means that under normal circumstances, 95% of the tiny particles (0.3 microns) can be blocked, according to the national standard GB/T 19083 for medical protective masks, when the gas flow is 85 L/min. The filtering efficiency of the mask for non-oily particles shall meet the requirements in the following table: Table 1: Filtration Grade of Medical Protective Mask From the above explanation, N95 is actually a five-layer mask made of polypropylene non-woven SMMMS, which can filter 95% of fine particles. Finally, let’s look at the requirements for S spunbond layer and M meltblown layer from the material point of view: M layer: meltblown layer Material requirements: high fluidity. Recommended materials: domestic materials such as Shandong Dawn degradation polypropylene: Z-1400, Z1500, imported metallocene polypropylene such as Basel HP461Y, MF650Y. S layer: spunbond layer Material requirements: high strength Recommended material: polypropylene with melt index of 25 ~ 60,KN95 Face Mask, such as Exxon-Mobile 2040 and Shanghai Secco 2040, is a good spunbond material. For example, the performance index of S2040 is as follows: Return to Sohu to see more Responsible Editor:. zjyuan-group.com
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