Textile Strength In Epidemic Prevention And Control

Under the epidemic situation, not only schools at all levels have begun to teach online, but with the help of powerful Internet platform, all kinds of live broadcast, online courses and online training in industry enterprises are also surging, which has played a vital role in improving the ability of enterprises, maintaining customer groups, ensuring operation and opening up new channels. "Textile and clothing weekly" opened the "today's Micro class" column in WeChat's official public number. Welcome everyone to join the online classroom and enhance it together.

In order to better help college students to establish scientific prevention and control, rational treatment and fight against the new crown pneumonia, Donghua University Textile Institute relies on the line of thinking and politics education special brand "New Forum Forum micro education", invites professors, counselors and epidemic prevention and control student volunteers to bring online cloud courses.

This time, I want to invite Huang Chenlai, teacher of the nonwoven material and Engineering Department of Donghua University textile school to bring you the first lesson of "textile power" in the epidemic prevention and control. Let's take a look.

New forum for ideological and Political Education

The following are the highlights of this issue.

Textile strength in epidemic prevention and control

This epidemic caused by pneumonia caused by the new crown virus has a great impact on the safety of everyone and the economic development of our country. I believe that the students also have a very cold winter vacation like me, and now that the network is developed, I can share with you some scientific and epidemic prevention and protection measures at the same time. Knowledge of weaving materials - most of the bacteria and viruses are transmitted through droplets. The so-called droplet is the mouthwash that flies into the air. Therefore, the most effective way for our ordinary people to prevent virus infection is to wear masks out of doors. When it comes to masks, they are inextricably linked to our textile materials, especially nonwovens.

Nonwoven materials in respirators

The mask is made up of surface layer, middle core layer, inner layer, elastic band and nose clip. The surface layer is exposed to the outer layer, which has waterproof effect. The middle core layer plays a core protective role to effectively prevent bacterial virus and other tiny particles from penetrating. The inner layer is the contact layer with our skin, that is, the mouth and nose. The surface and inner layer, that is, the two surfaces inside and outside, the two layers are made of spunbonded nonwoven materials, while the middle layer is melted nonwoven material.

Comparison of structure between spunbonded fabric and melt blown fabric

The structure of spunbonded nonwovens and melted nonwovens is distinctly different. You can see from their microscopic photographs that the diameter of spunbonded nonwovens is obviously larger than that of melt blown viscose fibers after enlarging 1000 times. The diameter of the spun nonwoven materials is generally 15~40 microns, while the diameter of melt blown fibers is only 1~5 microns.

Because the melt blown fibers are so fine and the pores between fibers and fibers are correspondingly smaller, a lot of particulates can be blocked by melt blown cloth. But it is far from enough to rely on holes formed between melt blown fibers to intercept particulates, bacteria and viruses, because the size of the objects that need to be intercepted is much smaller than that of the melt blown cloth, and there is a great chance of passing through these holes when passing through the melt blown fabric. Then can we make the melt blown fabric tighter or denser or replace the material with finer fiber diameter?

The idea of interception of particles, bacteria and viruses is in fact justified. The smaller the hole is, the greater the probability of blocking them. But for masks, there is a very important index besides the protective effect, exhalation and inspiratory resistance. If we make the hole small and tighten the material tightly, even though the protective effect is improved, the resistance of breathing will also increase significantly. If the mask is not worn for long, we will be panting.

Electrostatic adsorption effect of melt blown fabric

In order to enhance the protective effect and do not increase the exhale and inhale discomfort, we usually conduct electret treatment on the melt blown fabric. The so-called "electret" means using special technology to make the melt blown fabric have a lot of positive charges, and use the familiar physical effect of "electrostatic adsorption" to capture fine particles. There is a certain adsorption effect on particulate matter, but after the electret, we can see that a large number of fine particles are adsorbed on the surface of the fiber. When the virus passes through the melt spun cloth, though our hole is much larger than the size of the virus, the virus can be firmly absorbed by the static electricity on the fibers, so the respirator can protect us from the infection of the virus.

Nonwovens in surgical gowns and protective clothing

In addition to respirators, non-woven materials are widely used in protective clothing worn by our medical staff. Among them, SMS nonwovens, known as English spunbonded melt blown spunbond nonmanufacturing materials, are more famous. In this material, the upper and lower two layers of the S layer, that is, the spunbond layer, can play a very good role in protecting and waterproofing, and the M layer uses its small holes to prevent the patient's blood and body fluids from penetrating through the protective clothing, thus ensuring the safety of the medical staff. In addition to SMS, a large amount of Tyvek is also used in protective clothing, that is, a kind of polyethylene flash spinning nonwoven material. Dimension is also very fine. The diameter of the fiber is between 1~3 microns and similar to that of melt blown fabric. Therefore, it can also play a good role in waterproof and isolation. Compared with the melt blown cloth, the material has much higher strength, so there is no need for S layer, that is, spunbond layer to protect it.

Performance of protective material finishing

In protective clothing, besides nonwovens, we also need some finishing, for example, a very famous "three refusal", that is, water repellent, blood refusal, alcohol and antistatic finishing. After this arrangement, the protective performance of protective clothing can be further increased, and the comfort of clothing has also been greatly improved. In addition, protective clothing is usually combined with nonwoven materials and microporous breathable membranes, which greatly protect the comfort and protection of protective clothing.

Textile School of Donghua University

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