The medical mask is composed of mask body and tension belt. The mask body is divided into three layers: inner, middle and outer. The inner layer is skin friendly material (ordinary sanitary gauze or non-woven fabric), the middle layer is isolation filter layer (ultra-fine polypropylene fiber melt blown material layer), and the outer layer is special material bacteriostatic layer (non-woven fabric or ultra-thin polypropylene melt blown material layer).
According to the performance characteristics and scope of application, medical masks can be divided into: medical protective masks, medical surgical masks, general medical masks.
The medical protective mask is suitable for the protection of medical staff and relevant staff against the respiratory tract infectious diseases transmitted by air. It is a kind of close self-priming filter type medical protective equipment with high protection level, especially suitable for wearing when contacting the patients with respiratory tract infectious diseases transmitted by air or near-range droplets in the diagnosis and treatment activities. It can filter particles in the air, block droplets of droplets, blood, body fluids, secretions, etc., and belongs to disposable products. Medical protective masks can prevent most pathogens such as bacteria and viruses. Who recommends that medical personnel use protective masks against particles to prevent virus infection in the air of hospitals.
The medical protective mask conforms to GB19083-2003 technical requirements for medical protective mask, and the important technical indexes include filtration efficiency of non oil particles and air flow resistance. The specific indicators are as follows:
1) Filtration efficiency: under the condition of air flow (85 ± 2) l / min, the filtration efficiency of sodium chloride aerosol with median diameter (0.24 ± 0.06) μ m in aerodynamics shall not be less than 95%, that is to say, it shall meet the grade of N95 (or FFP2) and above. It can block the air-borne infectious factors with a diameter of less than 5 μ m or close contact with the infectious factors transmitted by droplets.
2) Suction resistance: under the above flow conditions, the suction resistance shall not exceed 343.2pa (35mmh2o).
3) When the sample is sprayed to the mask under the pressure of 10.9kpa (80mmHg), the inner side of the mask shall be free of penetration and other technical indicators.
4) The mask must be equipped with a nose clip, which is made of bendable plastic material with a length of more than 8.5cm.
5) Synthetic blood is sprayed at 10.7kpa (80mmHg) pressure to the mask sample, and there should be no penetration inside the mask.
The medical surgical mask is suitable for the basic protection of medical personnel or related personnel, as well as the protection against the spread of blood, body fluids and splashes in the process of invasive operation. It has a medium level of protection and certain respiratory protection performance. It is mainly worn in the clean environment with cleanliness less than 100000, operating room work, nursing patients with low immune function and body cavity puncture. Medical surgical masks can block most of the bacteria and some of the viruses, can prevent the medical staff from being infected, and can also prevent the microbes carried in the breath of the medical staff from being discharged directly, which poses a threat to the patients undergoing surgery. The filtering efficiency of medical surgical mask for bacteria should be over 95%. For suspected respiratory patients, disposable surgical masks should also be provided to prevent infection threat to other personnel in the hospital and reduce the risk of cross infection, but the effect of avoiding infection is less than that of medical protective masks.
It conforms to yy0469-2004 technical requirements for medical surgical masks. Important technical indicators include filtration efficiency, bacterial filtration efficiency and respiratory resistance. The specific indicators are as follows:
1) Filtration efficiency: under the condition of air flow rate (30 ± 2) l / min, the filtration efficiency of sodium chloride aerosol with aerodynamic median diameter (0.24 ± 0.06) μ m is not less than 30%.
2) Bacterial filtration efficiency: under specified conditions, the filtration efficiency of Staphylococcus aureus aerosol with an average particle diameter of (3 ± 0.3) μ m shall not be less than 95%; the bacterial filtration rate shall be ≥ 95%; the filtration rate of non oily particles shall be ≥ 30%.
3) Respiratory resistance: under the condition of filtration efficiency flow, the inspiratory resistance shall not exceed 49pa, and the expiratory resistance shall not exceed 29.4pa. When the pressure difference △ p between the two sides of the mask is 49pa / cm, the gas flow rate should be ≥ 264mm / s.
4) Nose clip and mask belt: the mask shall be equipped with nose clip, which is made of plastic material, and the length of nose clip shall be greater than 8.0cm. The mask belt shall be easy to wear and take, and the breaking strength at the connection point between each mask belt and the mask body shall be greater than 10N.
5) Synthetic blood penetration: when 2ml synthetic blood is sprayed to the outer side of the mask at a pressure of 16.0kpa (120mmhg), there should be no penetration on the inner side of the mask.
6) Flame retardant performance: the mask material shall be non combustible, and the burning time of the mask after leaving the flame shall be less than 5S.
7) Ethylene oxide residue: the ethylene oxide residue of the mask sterilized by ethylene oxide shall be less than 10 μ g / g.
8) Skin irritation: the primary irritation index of mask material should be ≤ 0.4, and there should be no sensitization reaction.
9) Microbial index: the total bacterial colony is ≤ 20cfu / g, and coliform, Pseudomonas aeruginosa, Staphylococcus aureus, hemolytic streptococcus and fungi shall not be detected.
The general medical mask is used to block the splashes out of the mouth and nose. It can be used for one-time health care in the general medical environment, with the lowest protection level. It is suitable for general health care activities, such as sanitary cleaning, solution preparation, bed cleaning unit, etc., or the barrier or protection of particles other than pathogenic microorganisms, such as flower powder, etc.
It conforms to the relevant registered product standards (yzb). Generally, there is no requirement for the filtration efficiency of particles and bacteria, or the filtration efficiency of particles and bacteria is lower than that of medical surgical masks and medical protective masks. Only 20.0% - 25.0% of 0.3 μ m diameter aerosols can be protected, and the filtration efficiency of particles and bacteria can not be achieved, and pathogens can not be effectively prevented from invading through the respiratory tract It can not be used.
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