The origin of protective clothing
The earliest medical protective clothing can be traced back to the 14th century. Medieval Europe was immersed in the terror of the "Black Death" because of its extremely contagious and pathogenic nature. According to incomplete statistics, it was only in 1348-1350. Within three years, nearly 30 million people in Europe alone lost their lives due to the Black Death.
And there are such a group of people known as "beak doctors", wearing beak-shaped masks that filter rotten odors, wearing robes and gloves to avoid direct contact with the source of infection. Selflessly treat patients, carry corpses, and try their best to stop the spread and spread of the plague.
Even so, in the lapse of 300 years, the "Black Death" directly killed nearly half of Europe's lives.
With the spread and spread of severe infectious diseases such as hepatitis, AIDS, SARS, and Ebola virus in modern protective clothing, the requirements for protective clothing are becoming higher and higher, not only to ensure that medical personnel can effectively isolate the virus, but also To ensure that medical staff have a certain degree of comfort during long wear.
Common fabrics cannot be effectively isolated
Ordinary fabrics and fabrics cannot effectively isolate viruses, even if they tightly wrap themselves, they cannot isolate viruses. Because textiles are tightly intertwined between threads. But this also leads to gaps between the threads and between the fibers and fibers that are invisible to the human eye.The virus can easily pass through, because the diameter of the virus is only about 100 nanometers, which means that the virus is closely packed together. It also requires at least 100,000 human eyes to barely observe.
At the same time, traditional fabrics have poor barriers to liquids. For example, Ebola virus transmitted through body fluids and blood can easily penetrate the traditional fabrics with liquids and contact the fragile mucosal skin to complete the infection.
Virus protection is undoubtedly a huge challenge for textile materials.
How to achieve effective isolation
The disposable medical protective clothing worn by medical staff nowadays are mostly made of non-woven fabric composite materials, which are made of multi-layer composite materials.
For medical protective clothing with SMMS structure, S is spunbond nonwoven fabric and M is meltblown nonwoven fabric.
S spunbond non-woven fabric: mostly composed of polyester and polypropylene filaments, with high linear density and regular mesh, which can provide good mechanical strength for "medical protective clothing" while filtering large particles. So as to ensure that medical staff will not tear in high-intensity work, and avoid being exposed to the source of infection. The breaking strength is not less than 40N, and the elongation at break is not less than 15%.
M melt-blown non-woven fabric: mostly composed of ultra-fine polypropylene fibers. These fibers have small diameter, large specific surface area, and are fluffy and soft. At the same time, high-pressure electrostatic treatment is adopted in the manufacturing process, which makes the fiber with electrostatic adsorption function, thereby further blocking the virus aerosol pollution. The filtering effect of 3 micron non-oily particles can be no less than 70%.
The combination of two different textiles makes each other complement each other.
The initial medical protective clothing was better filtered under dry conditions, and the protective effect against viruses under wet conditions was only about 40%, so it was necessary to add a fluorocarbon polymer or silicone-based water-repellent coating to The impermeability of medical protective clothing prevents blood and body fluids carrying viruses from penetrating into the clothing. The anti-osmotic water resistance is not less than 1.67kPa, and the anti-synthetic plasma penetration is greater than 1.75kPa.
Because the key to regulating body temperature is sweating, the sweat of comfortable clothing can vaporize out of the clothes. The protective clothing prepared by the above not only prevents liquid penetration, but also allows weak polarized vaporized sweat to penetrate through the gaps in the fibers to exclude the protective clothing, thereby ensuring the comfort of the protective clothing. The moisture permeability is not less than 2500g / (m2 · d).
For reusable medical protective clothing, PU polyurethane coating is used. The surface of the fabric is closed by a coating agent and has anti-permeability. The hydrophilic group in the coating or a microporous structure formed by a special method to ensure the moisture permeability of the fabric.
Modern medical protective clothing can still provide a certain degree of comfort while ensuring effective virus isolation, so as to ensure that medical staff can wear for a longer time to work.
But even under the modern protective clothing with a certain degree of comfort, the sweat of medical personnel in high-intensity rescue has penetrated the whole body.
Pay tribute to the greatest retrogrades of this era.