Expert Interpretation: Characteristics Of Masks And Protective Clothing

　　 The mask is urgent and the protective clothing is urgent. There is a phenomenon of human transmission of new coronavirus infection, so the demand for respirator protective clothing is greatly increased. Masks and protective clothing are undoubtedly the most important medical protective devices in this period. Most of the channels such as pharmacies and stores, and even Taobao shops, such as masks, are out of stock. At the time of the spread of the disease, the demand for medical workers at the forefront of the epidemic or the public has reached an unprecedented level.

　　 In order to maintain the supply of masks and protective clothing, industrial textiles enterprises have overcome difficulties in the early days of the country, started in advance and worked overtime without interruption.

　　 Of course, only qualified respirators and protective clothing can play an effective protective role. Unqualified protective products will only backfire and expose one life to the most dangerous air environment.

　　 This article tries to show you the technical principles, standards and technical features of masks and protective clothing.

　　 Mask: filter material is the core material. 

　　 Most of the respirators are made of two layers of non-woven fabric and a middle layer of filter cloth (called melt blown nonwovens). The principle of filtration is: filtration of dust mainly depends on the filter cloth in the middle. The main material of melt blown non-woven fabric is polypropylene, which is a kind of ultra-fine electrostatic fiber cloth, which can capture fine particles. The droplets containing pneumonia virus near the melt blown non-woven fabric will be adsorbed on the surface of non-woven fabrics by electrostatic, and can not be penetrated. This is how this material isolates pathogens. Because the dust is adsorbed on the filter cloth and the filter cloth can not be washed with static electricity, the respirator is disposable.

　　 At present, the main standards of masks in China are:

　　 GB 2626-2006 "respirator filter self respirator filter respirator", the full text of mandatory national standards;

　　 GB 19083-2010 "technical requirements for medical respirators", 4.10 of which is recommended, and the remaining terms are mandatory.

　　 GB/T 32610-2016 "technical specifications for daily protective respirators", recommended national standards;

　　 YY 0469-2011 "technical requirements for medical surgical masks", mandatory industry standard;

　　 YY/T 0969-2013 "disposable medical masks" recommended by the industry standard;

　　 Expert interpretation

　　 1, the medical respirator is in line with the mandatory standard of GB19083-2010 in China. It has good facial integrity, no expiratory valve, and the filtration efficiency is more than 95%.

　　 The N95 mask is called "N95" because it is one of the 9 kinds of particle respirators certified by the National Institute of occupational safety and health (NIOSH). Its name represents its filtering level: the filter material in the middle of the mask of "N", and the N series screen can protect non oil suspended particles, which should be replaced after accumulating more than 8 hours. The "95" represents the lowest filtration efficiency of 95%. After being certified by the US NIOSH, the efficiency of non oil particle filtration is more than 95%.

　　 The KN95 respirator is in line with China's GB 2626 mandatory standard, and the non oil particle filter efficiency is more than 95%.

　　 The filtration efficiency of the above level mask is basically the same as that of the filtration efficiency. However, the N and KN series respirators do not have the function of protecting the body fluid or blood spatter in the medical respirator. Therefore, N95 or KN95 respirators should be used cautiously in the medical environment.

　　 2. For people who are in pursuit of protection level and who are afraid of breathing, N or KN respirators equipped with expiratory valves can help reduce heat buildup and keep breathing easier, but virus carriers should not wear respirators with respirators to prevent virus from draining through breathing valves.

　　 3, the higher the filtration efficiency of respirators, the greater the resistance to respiratory airflow, the easier it is to create discomfort and affect the duration of wearing. Therefore, after ensuring the basic protective function requirements, we should try to choose respirators with lower respiratory resistance and stronger overall comfort so that they can maintain long time wear and effectively protect air pollution. If it is only a group of influenza viruses, infectious droplets or other harmful particles that protect the air, it is enough to use normal N90 or KN90 respirators.

　　 4, at present, some of the masks on the market are executed by the GB/T32610 standard. This is the first national standard of domestic respirators. It is suitable for filtering the air into the mouth and nose, so as to stop harmful gases, odors, and droplets entering and wearing the mouths and mouths of wearers. It is mainly divided into cotton masks, non-woven respirators, polymeric mask, active carbon powder filter masks, and activated carbon fiber felt mat masks. Although it has some protective functions, it can not be used to prevent respiratory pathogens, and is not a medical category. Other common masks may be cotton, gauze, sponge, canvas and velvet. They can only isolate some of the dust in the air, and basically have no protective effect.

　　 5, GB19083-2010 "medical respirator technical requirements" is the real source of medical mask respirator technical standards, read the whole GB original text, it has many similar technical parameters with GB2626, for example, it also divided into 3 filter efficiency levels, also detected non oily particulate matter filter (contrast KN mask), but it directly abandoned the oil particle parameters requirements (that is, KP mask completely different), and 1 level is 95% or 95%, the highest level 3 is more than 99.97%, equivalent to direct alignment KN95 and KN100, no KN90 lower level.

　　 That is to say, the minimum standard that meets the GB 19083 filtering performance is equivalent to the KN95 standard of GB2626. But please note that there is no "N95" in our GB19083. Instead, we use the "1 level", "2 level" and "3 level" statements to show the efficiency of filtering, and the general 1 level can achieve the "N95/KN95" requirement. That is to say, as long as any GB "19083" standard "medical respirator", it has reached the N95 and KN95 level of filtration efficiency.

　　 6, from design and performance requirements, if ranked according to the priority of wearer's protection ability (from high to low):

　　 Medical masks, >N95/KN95 masks, medical surgical masks, disposable medical masks, ordinary cotton masks.

　　 From the analysis, the mask filter material is very important for the anti virus effect. It is the core of the core material of the respirator and the most important part.

　　 TEDA, a wholly owned subsidiary of Tianjin TEDA Limited by Share Ltd, is a well-known masks filter manufacturer in China. It is also the main establishment of the GB/T32610 standard for the technical specification of daily protective mask. According to statistics, the domestic mask production capacity is about 20 million per day. As one of TEDA's clean products, according to the daily capacity of 7 tons of filter material, the mask can be produced in about 7 million, occupying more than 30%.

　　 In terms of the quality of filter materials, the mask material is melt blown ultrafine fiber, and the fiber diameter can be as small as 1 microns. The electrostatic electret technology is used to make large particles in the air intercepted while tiny bacteria and particulates are effectively adsorbed. TEDA's clean respirator filter material meets the requirements of N95 and N99 in the US NIOSH42CFR-84 standard, EU EN149 standard FFP2, FFP3 level requirements, and GB GB2626-2006 standard KN, KP series requirements, these are N95 and above standards.

　　 As a state-owned enterprise, TEDA clean has opened all 4 masks filter line, at all costs, do all manpower, financial and material resources to ensure product supply of high-quality mask filters.

　　 It is also understood that Donghua energy Limited by Share Ltd occupies about 20% of the domestic polypropylene fiber market, and the company plans to become the world's largest polypropylene producer in the next five years. In response to the epidemic, the company has supplied more than 10000 tons of medical nonwovens special material Y381H to medical and health production enterprises such as Mei run shares and Guangdong Bedford.

　　 Protective clothing: prevention of bacterial penetration is the key. 

　　 Compared with masks, medical protection compliance with materials to production technology is obviously higher. At present, there are three kinds of commonly used medical protective clothing. One is coating material. Most domestic enterprises adopt wet or dry polyurethane, polyacrylate and polyvinylidene fluoride to finish the fabric finishing, and then use this material to make protective clothing. The two is PU and TPU membrane composite. This composite material has certain improvement in moisture permeability and comfort compared with coating material. The three is PTFE microporous membrane composite. The domestic army has a small batch application in the special service of military uniform, and its application in medical protective clothing is still in the trial stage. Polytetrafluoroethylene microporous membrane can effectively solve the two shortcomings of poor durability and poor moisture permeability of coating materials, PU and TPU composite materials. The disadvantage of PTFE is the high cost.

　　 Before the outbreak of SARS in 2003, there was no national standard to regulate medical protective surgical clothing in China. In April 29, 2003, the GB19082-2003 "medical disposable protective clothing technical requirements" was promulgated and applied to disposable protective clothing. At present, the mandatory national standard GB19082-2009 "medical disposable protective clothing technical requirements" is adopted in China instead. According to experts, the ability to prevent bacteria from penetrating protective clothing is the key to the performance of medical protective clothing. In the experiment, water repellency is used to indirectly indicate its shielding performance. In addition, it also has good blood barrier function, no leakage, good biological performance, no allergy to skin and sensitization. Comfort refers to the comfort of the wearer, expressed by softness and loose water.

　　 At present, there is still a big gap between the level of medical protective clothing in China and abroad. In order to alleviate the serious shortage of production and supply of medical protective clothing, the state issued the notice on issues related to the production and use of protective clothing during the epidemic period, requiring China to carry out overseas standards convergence and increase classification and classification supply. Among them, the supply of emergency medical supplies protective clothing that meets the EU standards is increased, and the designated production and identification mark management is adopted for isolating the sick wards (rooms) and the isolation wards (rooms).

　　 Head of the Ministry of industry and Commerce The emergency medical material protective clothing should conform to the EN14126 standard of the European medical protective clothing (including liquid barrier grade above 2), and obtain the EU CE certification, or liquid tight protective clothing (type3, comply with the EN14605 standard), spray tight protective clothing (type4, meet the EN14605 standard), and prevent solid particulate matter protective clothing (type5, meeting the ISO13982-1&2 standard).

　　 Emergency medical supplies protective clothing shall be designated production and mark management. That is to say, it can only be produced by fixed-point production enterprises. The designated production enterprises should ensure that the product quality is consistent with the implementation standards. Product packaging should be targeted at the target product, product name, product scope, product size specification, product standard number, designated production enterprise name and other information. Emergency medical supplies protective clothing is only used to isolate observation wards (rooms), isolation wards (rooms), and can not be used for isolation of intensive care units (rooms) and other places with strict microbial control.

　　 In fact, China is also making progress in the field of medical protective clothing. As early as 2003, at the critical time of national SARS prevention and control, the new Mstar Technology Ltd of China Textile Science and Technology Institute, which was held by the China Textile Science Research Institute, developed medical protective clothing composite fabrics on the basis of developing medical hygienic materials with American companies in advance. The new Tianjin spinning Mstar Technology Ltd, located in Wuqing high tech park, is the production base of the National Engineering Research Center of fiber matrix composites, mainly engaged in research, development and production of coated fabrics and high-performance textile materials. The production of non-woven fabric and functional composite membrane materials can play a barrier, moisture permeability, waterproof effect. Barrier function can effectively resist viruses and bacteria. China Textile new material was commended for developing and producing medical disposable protective clothing fabrics when fighting SARS in 2003. After being informed of the epidemic, China Textile hospital set up an emergency working group for medical protective materials and products on New Year's Eve to enter the "combat state". The new material of China spinning began to produce continuously for 24 hours. It can produce 20 thousand meters disposable medical protective clothing every day, equivalent to nearly 10000 sets of protective clothing. The production plan of 1 million meters of medical protective clothing fabric has been completed, and the research and development of reusable new medical protective fabrics is speeding up.

　　 It is understood that the China Textile Institute has also developed all the protective clothing fabrics for the epidemic, multiple use of surgical clothing and anti-virus protective clothing fabrics, and speed up the clinical trials in Tianjin.

　　 In the second year of the lunar new year, the Ministry of industry and commerce, China Textile Federation and other enterprises have gone to the field to investigate the production of medical materials. Wang Wei, director of raw materials division, Ministry of industry and information technology In the process of investigation, the production of medical masks and protective clothing is closely related to the life safety of front-line medical staff. Local governments are urged to urge local related enterprises to resume production as soon as possible, and support necessary issues such as staff returning to factories and fund advance in the process of production, while strengthening the connection with the relevant departments and departments in the relevant provinces, and doing well in the allocation and transportation of materials and materials in the industrial chain.

　　 Li Lingshen, vice president of China Textile Industry Federation Also pointed out in the survey, aiming at the shortage of raw materials and auxiliary materials raised by enterprises, the association has launched the tracking and docking work of key enterprises in the whole industry chain of the epidemic prevention products, and recommended that the production enterprises should comb out the detailed demand information so as to enable the association to support and coordinate the whole production level in a timely and effective manner.