Electrostatic electret, filtration efficiency, product quality and standards

2023-11-26 21:45:25

The melt blown fabric used for mouth placement adopts a melt blown non-woven process, and the polymer is stretched into ultrafine fibers with an average diameter of<5um through high-pressure and hot air. The fibers in the filter material are randomly arranged and cross shaped with the interlayer, forming a fiber filter layer with multiple curved channels, with pore sizes ranging from 5 to 40um. Here, smaller pores increase mechanical filtration performance, although the cost is higher pressure loss.

The particles of viruses, bacteria and other microorganisms, including the novel coronavirus, are very small. They cannot exist independently in the air and need to attach to the moisture, droplets, dust, aerosols, etc. in the air to survive and spread. Therefore, oral materials must have excellent performance in filtering droplets, dust, pollen, and fog particles. The door has different filtration efficiency requirements based on its application, such as the medical protective opening must comply with the GB19083-2010 standard, and the filtration efficiency of non oily particles is 295%. It is required to pass the synthetic blood penetration test and set requirements for microbial indicators. The filtering efficiency in the standard is divided into three levels, with level 1 being 295% and the highest level 3 being 299.97%. Daily protective snow products such as N95 are certified standards in the United States, which can filter out over 95% of non oily wild particles under specified air flow rates (85L/min), hence the name N95. If more than 99% of particulate matter can be filtered, it can be called a 99 port filter. The corresponding domestic standards for N95 and N99 are KN95 and KN99 masks, even with nano-sized fibers, they are often insufficient to separate the smallest particles in air or liquid. The melt blown filter medium needs to undergo electrostatic electret treatment to carry a large amount of electrostatic charges on the surface of the fibers. By using electrostatic adsorption to capture fine particles, it can significantly and cost-effectively improve filtration performance without increasing the output positive force. In other words, only the melt blown non-woven fabric after electret treatment can achieve over 95% filtration without changing the respiratory positive force, effectively preventing viruses, Meet the standards for medical oral placement.

In fact, the production of standard medical mouthpieces using meltblown cloth is relatively low and the cost is high. Currently, some mouthpieces on the market use meltblown cloth that has not undergone electret treatment, and the filtration efficiency is not up to standard, which cannot effectively block viruses. There are even mouthpieces without a filter layer. According to the Southern Metropolis Daily, the current quotations for melt blown fabrics are around 200000 to 300000 yuan per ton. For mouthpiece manufacturers who sell their eggs at factory prices, such prices cannot be borne.

On the one hand, they are concerned about the high price of meltblown fabrics, and on the other hand, they are also concerned about whether the meltblown fabrics provided by intermediaries comply with quality control. Many people are worried about getting fake meltblown fabrics at such high prices, especially now that testing agencies are too busy. In addition, many intermediaries claim to have imported meltblown fabric in their hands, but it is difficult to distinguish between true and false because they can only provide English testing reports.

Whether the quality and filtration efficiency of melt blown non-woven fabric can meet the filtration standards required for medical mouth placement may become a key and difficult point for subsequent supervision.