How to Make N95 mask made – A Manufacturing
The domestic epidemic situation has reached an urgent time. The woman returned to Henan from Wuhan to asymptomatic, and 5 relatives have new pneumonia! The National Health and Welfare Commission has confirmed that asymptomatic people are also infected! Six people in Anhui were diagnosed with new pneumonia after attending a classmate’s meeting, with an average age of 22 years. To prevent the epidemic from continuing to spread, masks have now become a must-have item for people. It is very important to keep a meter of noodles, wear masks, and wash hands frequently. Policies are introduced in many places, and you will be punished without wearing a mask in public! Today we are going to explore what material is the mask made of?
So why can masks stop the spread of viruses? What kind of material is it?
We usually say that masks are non-woven materials. Non-woven fabrics are non-woven fabrics, which are made of oriented or random fibers.
Specific to the mask, all its raw materials are polypropylene (Polypropylene, PP), medical masks are generally multi-layer structure, generally referred to as SMS structure, schematic diagrams shown in Figures
The several layers of masks we often say are not specified in the national standard GB / T 32610 of masks. If it is a medical mask, it should be at least 3 layers, that is, SMS (2 layers S layer and 1 layer M layer ), Currently the highest number of layers in China is 5 layers, namely SMMMS (2 layer S layer and 3 layer M layer), it is not difficult to make a mask, the more difficult is to make SMMMS cloth, the price of an imported non-woven equipment It is hundreds of millions of yuan, and the most expensive medical non-woven equipment I have seen is 500 million yuan.
The S in this refers to the spunbond layer (Spunbond), the fiber diameter is relatively thick, about 20 microns (μm), the two layers of S spunbond layer is mainly used to support the entire nonwoven fabric structure, does not have much effect on the barrier .
The most important thing in the mask is the barrier layer or the melt-blown layer M (Meltblown). The fiber diameter of the melt-blown layer is relatively thin, about 2 microns (μm), so it is only one tenth of the diameter of the spunbond layer. This prevents Bacteria and blood penetrate its vital role.
If the S spunbond layer is too much, the mask is harder, and if the meltblown layer M is too much, it is more difficult to breathe, so the isolation effect of the mask can be judged from the difficulty of breathing the mask. The more difficult the breathing, the better the blocking effect However, if the M layer becomes a thin film, it will basically be unable to breathe, the virus is blocked, and people are almost out of it, so this is also a technical problem.
In order to explain the problem better, we compare the S fiber of the spunbond layer, the M fiber of the meltblown layer, and the hair as follows. The diameter of the M fiber of the spray layer is close. Of course, the R & D personnel are still developing finer fibers to ensure better antibacterial barrier.
As mentioned earlier, the thinner the M layer, the more able to block the entry of microscopic particles such as bacteria, such as N95, which means that under normal circumstances, it can block 95% of microscopic particles (0.3 microns), according to the national standard GB / T 19083 requires that when the gas flow rate is 85L / min, the filtering efficiency of the mask for non-oily particles meets the requirements of the following table:
Filter grade of medical protective mask
From the above explanation, N95 is actually a 5-layer mask made of polypropylene nonwoven SMMMS that can filter 95% of fine particles.
Finally, let’s take a look at the requirements of the S spunbond layer and the M meltblown layer from a material perspective:
M layer: meltblown layer
Material requirements: high fluidity.
Recommended materials: domestic materials such as Shandong Dawn Degradation Polypropylene: Z-1400, Z1500, imported such as Basel Metallocene polypropylene HP461Y, MF650Y.
S layer: Spunbond layer
Material requirements: high strength
Recommended material: Polypropylene with a melt index of 25 to 60, such as Exxon Mobil Exxon-Mobile and Shanghai SECCO 2040 are good spunbond materials, such as S2040 performance indicators are as follows:
In addition, the editors shattered their thoughts: three more points
1. What kind of mask do you bring? Medical mask or N95 type