Direct hit: how to spray meltblown cloth, how to produce masks! 【Attached analysis of mask standards in various countries】

Direct hit: how to spray meltblown cloth, how to produce masks! 【Attached analysis of mask standards in various countries】

China is a big mask industry country, producing about 50% of the masks in the world. Before the outbreak, the highest daily output of Chinese masks was more than 20 million. The data shows that the growth rate of the mask industry output value in mainland China from 2015 to 2019 is above 10%. In 2019, the output of masks in mainland China exceeded 5 billion, with an output value of 10.235 billion yuan. The fastest mask production speed is 120-200 pieces / second.

What is meltblown cloth?

Cut out a used medical mask, you will find that the mask has three layers, (inner layer) moisture absorption layer, (middle layer) core filter layer, and (outer layer) water blocking layer.



Because according to the national production regulations, medical masks contain at least 3 layers of non-woven fabrics (N95 grade masks, structurally optimized: (middle layer) the core filter layer is more, and the thickness is thicker).



Layer S: Polypropylene special resin (Sinopec)-Non-woven fabric factory-Mask factory M layer: High melt index polypropylene special resin (Sinopec)-Modified plastics plant (during epidemic prevention, Sinopec researched and produced meltblown Special materials)-Meltblown Nonwovens Factory-Mask Factory.

Meltblown cloth, commonly known as the "heart" of the mask, is the filter layer in the middle of the mask, which can filter bacteria and prevent the spread of germs. Meltblown cloth is a film made of polypropylene with high melt index. It is a film composed of many crisscross fibers stacked in random directions. The fiber diameter ranges from 0.5 to 10 microns, and the fiber diameter is about 30 cents one.



The following picture is a photograph of the structure of the meltblown cloth:



(Photographed by Fina Desktop Scanning Electron Microscope)

When you see the picture, do you worry that the gap in the meltblown cloth is so large, how do you filter viruses in the environment? Although the size of the new coronavirus is very small, about 100 nanometers (0.1 micrometers), the virus cannot exist independently. The main transmission routes are secretions and droplets when sneezing. The size of the droplets is about 5 micrometers. One, second, the meltblown cloth is essentially a fiber filter. When the droplets containing the virus are close to the meltblown cloth, they will also be electrostatically adsorbed on the surface and cannot penetrate.



Schematic diagram of fiber filtration mechanism

Although the raw materials of the S layer and M layer of the mask are polypropylene-specific resins, the special materials for melt-blown fabrics differ greatly from other non-woven fabrics in the production process and performance.



Meltblown ▲

The meltblown cloth is really 'sprayed'