Medical masks are mostly made of one or more layers of non-woven fabrics. The main consumer processes include meltblown, spunbond, hot air or needle punching. They have the effects of resisting liquids, filtering particulates and bacteria. They are a kind of medical protection. textile.

Constitute

The medical mask is composed of a mask face and a tightening belt. The mask face is divided into inner, middle and outer layers. The inner layer is skin-friendly (general hygienic gauze or non-woven fabric), and the middle layer is an isolation filter layer (ultra-fine polypropylene) Fiber melt-blown data layer), the outer layer is a special material antibacterial layer (non-woven fabric or ultra-thin polypropylene melt-blown data layer).

Classification

According to performance characteristics and application scope, medical masks can be divided into: medical protective masks, medical surgical masks, and ordinary medical masks.

1. Medical protective mask

Medical protective masks are suitable for the protection of airborne respiratory infections by medical staff and related staff. It is a close-fitting self-priming filter medical protective equipment with high protection level, especially suitable for contact with airborne transmission during diagnosis and treatment activities Or worn by patients with respiratory tract infections spread by droplets at close intervals. It can filter the particles in the air, block droplets, blood, body fluids, secretion droplets, etc., which are disposable products. Medical protective masks can prevent most pathogens such as bacteria and viruses. WHO recommends medical staff to use protective masks against particles to avoid virus infection in hospital air. 

Medical protective masks conform to the GB19083-2003 "Technical Request for Medical Protective Masks" specification, and important technical indicators include non-oily particle filtration efficiency and airflow resistance. The detailed indicators are as follows: [3]

1) Filtration efficiency: Under the condition of air flow (85 ± 2) L / min, the filtration efficiency of the aerodynamic median diameter (0.24 ± 0.06) μm sodium chloride aerosol is not less than 95%, which is consistent with N95 Or FFP2) and above. It can block airborne infectious agents with a diameter of <5μm or close contact with infectious agents transmitted by droplets.

2) Inhalation resistance: Under the above flow conditions, the inhalation resistance does not exceed 343.2Pa (35mmH2O).

3) For the sample sprayed on the mask under the pressure of 10.9Kpa (80mmHg), the inside of the mask should not show the technical indicators such as penetration.

4) The nose mask must be equipped with a nose clip, which is made of bendable plastic material and has a length> 8.5cm.

5) Synthetic blood is sprayed towards the mask sample at a pressure of 10.7kPa (80mmHg), and the inside of the mask should not be saturated.

2. Medical surgical mask

Medical surgical masks are suitable for the fundamental protection of medical staff or related personnel, as well as the protection against blood, body fluids and splashes during the invasive operation. The protection level is medium and has certain respiratory protection performance. It is mainly worn in clean environments with a cleanliness level of less than 100,000, working in the operating room, nursing patients with low immune function and stopping body cavity puncture and other operations. Medical surgical masks can block most local bacteria and local viruses, can prevent medical staff from being infected, and can also avoid the direct discharge of microorganisms carried by medical staff's breath, which constitutes a threat to patients undergoing surgery. Medical surgical masks request that the filtration efficiency of bacteria reach more than 95%. Suspicious respiratory patients should also be provided with disposable medical surgical masks to avoid threats to other hospital personnel and reduce the risk of interstitial infections, but the effectiveness of preventing infections is not as good as medical protective masks. 

In accordance with the YY0469-2004 "Technical Request for Medical Surgical Masks" specification, important technical indicators include filtration efficiency, bacterial filtration efficiency and respiratory resistance. The detailed indicators are as follows:

1) Filtration efficiency: Under the condition of air flow (30 ± 2) L / min, the filtration efficiency of aerodynamic median diameter (0.24 ± 0.06) μm sodium chloride aerosol is not less than 30%.

2) Bacterial filtration efficiency: under regular conditions, the filtration efficiency of aerosols of Staphylococcus aureus with a uniform particle diameter of (3 ± 0.3) μm is not less than 95%; bacterial filtration rate should be ≥95%; non-oily particles The filtration rate should be ≥30%.

3) Breathing resistance: Under the condition of filtration efficiency flow, the inhalation resistance does not exceed 49Pa, and the exhalation resistance does not exceed 29.4Pa. When the pressure difference △ P of the gas exchange between the two sides of the mask is 49Pa / cm, the gas flow rate should be ≥ 264mm / s.

4) Nose clips and mask straps: Nose clips should be provided on the mask. The nose clips are made of plastic materials and the length of the nose clip should be greater than 8.0cm. Mask bands should be worn for convenience, and the breaking strength at the joint between each mask band and the mask body should be greater than 10N.

5) Synthetic blood penetration: After 2ml of synthetic blood is sprayed at the pressure of 16.0kPa (120mmHg) toward the outer side of the mask, the inner side of the mask should not be saturated.

6) Flame-retardant performance: Non-flammable materials should be used for the mask material, and the mask should be extinguished for less than 5s after the flame is separated.

7) Residual amount of ethylene oxide: For masks sterilized by ethylene oxide, the residual amount of ethylene oxide should be less than 10μg / g.

8) Skin irritation: The primary irritation index of the mask data should be ≤0.4, and there should be no allergic reaction.

9) Microbial indicators: total bacterial colonies ≤20CFU / g, and no coliform bacteria, Pseudomonas aeruginosa, Staphylococcus aureus, hemolytic streptococci and fungi shall be detected. [5]

3. Ordinary medical mask

Ordinary medical masks are used to block spouts exhaled from the oral cavity and nasal cavity, and can be used for one-time hygiene care in ordinary medical environments with the lowest protection level. It is suitable for general hygiene care activities, such as sanitation, liquid distribution, cleaning bed units, etc., or the blocking or protection of particles other than pathogenic microorganisms such as pollen.

In line with the relevant registered product specifications (YZB), the general 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 reaching 20.0% for 0.3μm diameter aerosols -25.0% protection effect, can not achieve the filtration efficiency of particles and bacteria, can not effectively prevent pathogens from invading the respiratory tract, can not be used in clinical invasive operations, nor can it protect particles and bacteria and viruses, only limited to dust particles Or aerosol plays a certain mechanical barrier.

How to use

1. Carefully cover the mouth and nose with a mask and fasten it to minimize the gap between the face and the mask;

2. When using, prevent touching the masks-after touching the used masks, for example to remove or clean the mask, wash your hands with soap and water or use alcohol hand sanitizer;

3. After the mask is wet or infected with moisture, replace with a new clean and dry mask;

4. Do not use disposable masks repeatedly. Disposable masks should be discarded after each use.

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