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Industrial medical face mask connector vent valve N95 respirator is one of nine kinds of particle respirators certified by NIOSH (National Institute for occupational safety and health). "N" means not resistant to oil. "95" means that the particle concentration in the mask is more than 95% lower than that outside the mask when exposed to a specified number of special test particles. 95% is not the average, but the minimum. N95 is not a specific product name. As long as the product meets N95 standard and passes NIOSH review, it can be called "N95 mask". The degree of protection is N95, which means that under the test conditions specified in NIOSH standard, the filtering efficiency of the filter material of the mask for non oily particles (such as dust, acid mist, paint mist, microorganism, etc.) reaches 95%.
Non-woven fabrics /
It is generally said that the mask is made of non-woven fabric. Compared with textile fabric, non-woven fabric is made of directional or random fibers. As for the mask, its raw materials are all polypropylene (PP for short). The mask for medical use is generally multi-layer structure, generally referred to as SMS structure. See the figure below for the schematic diagram.
And we often say that several layers of masks, in the national standard of masks GB / T 32610 does not stipulate that if it is a mask for medical use, it should be at least three layers, that is, SMS (two layers of S and one layer of M). At present, the highest number of layers in China is five layers, that is smmms (two layers of S and three layers of m). It is not difficult to make a mask, but it is more difficult to make smmms cloth. The price of an imported non-woven fabric equipment is more than 100 million yuan
In this case, s represents spunbond, whose fiber diameter is relatively thick, about 20 microns (μ m). The main function of two layers of s spunbond is to support the entire non-woven fabric structure, which has little effect on barrier.
The most important part of the mask is the barrier layer or melt blown layer m (meltblown). The fiber diameter of the melt blown layer is relatively small, about 2 microns (μ m), so it is only one tenth of the diameter of the spunbond layer, which is very important to prevent bacteria and blood from penetrating.