The Latest "Children Mask Technology Specification" Recommended National Standard Interpretation Came.

In May 6, 2020, the General Administration of market supervision (SAC) formally issued the recommended national standard (GB/T) for the technical specification of children's mask 38880-2020 (hereinafter referred to as the "code"), which is promulgated. The code applies to masks worn by children aged 6 to 14 years and below. Children's respirators are classified into child protective masks and child hygiene masks according to their performance.

The norms in the specification are mainly based on three aspects: protective performance, wearing comfort and safety. The specification provides the basis for proper selection and wearing children's masks, standardizing the industry's competition order and strengthening market supervision, providing technical support and standard guarantee for children's mask manufacturers.

A few days ago, experts from Beijing Labor Protection Science Institute, Beijing medical equipment inspection institute, China Standardization Research Institute, children's Hospital Affiliated to Capital Institute of Pediatrics, Guangzhou customs technology center, Donghua University and masks and masks material backbone enterprises and other research institutes, such as individual protection, medical and health, ergonomics, textile materials, testing and other experts, A large amount of data collection, comparison and analysis were carried out on the materials, structures and properties of respirators, and the design and test methods of the respirators were designed.

1 Jin Xiangyu, Professor of nonwoven materials and Engineering Department, School of textiles, Donghua University: three measures to improve melt filter material efficiency and low resistance filter performance

Melt blown nonwoven material, as the core filter layer of mask, has the characteristics of fine fineness, small aperture, large specific surface area and high porosity. It has certain permeability and excellent filtration function. The key technology of producing high efficiency and low resistance melt blown filter material mainly includes three aspects.

The first is the technology of melt and spray fiber diameter micro nano technology. By improving the design of spinneret structure and selecting high polymer finger chips, the diameter of melt blown material and the filtration efficiency can be reduced. For example, the diameter of the spinneret holes of some advanced spinnerets is up to 0.10mm, and the hole density is more than 100 holes / inches. The length diameter ratio of the spinneret hole can be more than 35, and the melt pressure can reach 10.4MPa, which is conducive to the superfine production of melt blown fiber.

The two is electret processing technology. Electret technology is particularly important in the industrial production of melt blown filter materials. Electret treatment can significantly improve the filtration efficiency without affecting the physical structure of the material and increasing the filtration resistance. There are many kinds of electret technology in China, and corona electret technology is most common. Besides, there are technologies such as water pole and hot air pole. Under certain process temperature and humidity, the corona electret can move from "shallow trap" to "deep well", which makes the charge storage more stable. The temperature affects the charge mobility and the amount of charge stored inside the material. At present, using corona electret melt blown nonwoven filter material, the filtration resistance can be less than 90Pa, and the filtration efficiency can be more than 99%.

The three is polymer modification technology. By enhancing the electret effect by modifying the resin with inorganic / organic materials, the timeliness of filtration performance of melt blown materials can be improved. The technology of polymer modification and addition of additives can break through the common technical problems of short duration of melt blown nonwoven filter media, and greatly enhance the strategic reserve capacity of China's protective products. Donghua University conducted a time comparison experiment on the filter material of the modified additive melt blown mask for respirator (KN95 mask's surface density of 50g/m2). The results showed that the filtration efficiency before storage was 99.4% (gas flow rate was 85L/min). After 8 years of sealed storage, the filtration efficiency was 97.05%, the filtration efficiency value decreased by less than 3% in 2019, and the electret effect was stable, which could fully meet the long-term battle of the respirator. Slightly stockpile demand.

The "standard" requires that the respirator respirator should have more than 95% filtration efficiency for non oil particles under the 85L/min test flow, and the respiratory resistance at 45L/min is not higher than 45Pa. The respirator respirator for children has more than 90% filtration efficiency for non oil particulate matter under the 32L/min test flow rate, 95% above the bacterial aerosol filtration rate, and the ventilation resistance is less than 30P. This index has put forward higher requirements for mask filter materials. It is necessary for the filter production enterprises to have certain technical strength and production experience accumulation. If the enterprises in the new melt blown industry during the new crown pneumonia epidemic situation need to produce filters for national standard children's respirators, we need to strengthen professional theory, engineering technology, polymer performance research, or carry out technical transformation of related equipment.

2 Liu Ji, an associate researcher of Beijing Institute of labor protection science: Children's masks give consideration to comfort and protective effects.

Compared to adult masks, children mask market is small, and the sizes of children in different age groups are quite different. To produce children's masks that conform to national standards, the key is to solve the problems of filtration and mask materials. The object of investigation of particulate matter filtration efficiency and bacterial filtration efficiency is the filter material used for respirators, and it is an international evaluation index for respiratory filter materials.

Judging from the testing method, the evaluation of particulate matter filtration efficiency and bacterial filtration efficiency of the specification is based on current national standards and industry standards. The test requirement is basically the same as that of GB 2626-2006, which is higher than that of GB 19083-2010. The test of bacterial filtration efficiency of masks is consistent with the current industry standard YY 0469-2011. The consistency of the testing methods ensures the scientificity of the standard filter efficiency test method for mask materials and the consistency with the existing mandatory national standards and industry standard systems, which is convenient for the use of mask manufacturers, and is also convenient for market regulators and product testing organizations to carry out.

The protective effect is a technical index to evaluate the protective ability of respirators to particulate matter during wearing. The protective effect was first introduced by the recommended national standard GB/T 32610-2016 "daily protective mask technology specification". In the code, we continue to use this method to test the protective ability of the respirator during the actual wearing process, and have made 3 improvements. First, the five actions of static shaking head nod speech quiescence were introduced to simulate the possible behaviors of children wearing masks, and the effects of these actions on the protective ability of respirators were investigated. The above activities were basically consistent with the mandatory national standards GB 2626-2006 and GB 19083-2010, which ensured the overall investigation. The two is to modify the respiratory rate of 20 times /min, corresponding respiratory flow rate of 20L/min, higher than that of 6~9 years old children's short-term breathing volume, slightly higher than the short-term breathing volume of children aged 9~12 under moderate exercise condition, and ensure that the breathing process of the simulated head can reflect the breathing characteristics of respirator users. Three, according to the national standard GB/T 26160-2010 "minors' head and face size", the size specification and classification of the test die are carried out to ensure the representativeness of the test die. The improvement of these three aspects has made the test of the protective effect of the child respirator more comprehensive and scientific. The standard stipulates that the protective effect of child protective masks should be more than 90%, which is consistent with the leakage rate of KN95 level masks in national standard GB 2626-2006, and ensures the effective protection of respirators.

Comfort requirement (respiratory resistance) is the main index to investigate the respirator's impediment to the breathing process of the respirator. The test method is to wear the mask on the analog head mold, and test the increase of the resistance of the test system under the prescribed flow condition.

The "standard" stipulates that the flow rate of respiratory resistance test is (45 + 2) L/min, which can reflect the breathing process of children. At the same time, it is tested that the head mould with the size of minors is tested to ensure the actual wearing effect of the respirator. The standard establishment group stipulates the resistance of children's mask. The 45L/min test shows that the inhalation resistance should not exceed 45Pa, which ensures children's wearing safety at lower ages.

3 Huang Li Na, a researcher at Guangzhou customs Technology Center: analyzing behavior characteristics and strengthening children's awareness of risk prevention

Compared with adults, children have their own behavioral characteristics. The formulation of norms mainly considers children's behavior characteristics. Active and active is the nature of children. Children may wear masks and pull tongue when they are wearing masks. Therefore, the Code stipulates that masks and facial contact materials must not be printed or dyed, and the requirements for chemical residues and pH values of mask materials are significantly higher than those of adults. Especially for ethylene oxide limits of less than 2ug/g, fluorescent whitening materials can not be detected. 。

In order to ensure that children are not stained by masks, the color fastness is used as an assessment index, and the reference value is set out in reference to GB 18401-2010 national basic safety technical specification for textile products.

Considering the characteristics of children's behavior, the specification has increased a number of physical performance indicators compared to adult mask standards. If the respirator is not used during the use of the respirator, the mask should not be laced. There is no obvious pressure and tenderness during the wearing process, and the head movement will be less affected. At the same time, it is stipulated that the nose clip should be made of plastic material, with a length of more than 5.5cm, and the nose clip has certain folding resistance requirements. The specification fully considered the influence of children's behavior characteristics on the safety of wearing masks.

Children lack the ability to analyze and judge things. When danger comes, they may be hurt by lack of self-protection ability and risk aversion consciousness. For example, the skin allergies that may occur during wearing masks, the respiratory discomfort caused by the jumping process, the risk of suffocation caused by moisture and water, and the potential danger of not wearing proper masks. The specification also fully takes into account the weak sense of danger of the children themselves, and gives relevant warning contents, and requires that the production enterprises must clearly identify them.

According to the developmental characteristics of children at different ages, the specification divides children's respirators into large, medium and small models, which can meet the needs of children in different age groups. Under the premise of safety and protection, parents are allowed to choose the most appropriate respirators for children.

The release of the code provides a reference for other countries to formulate children's mask standards. Children in different countries may have different patterns of life, but there are similarities in some behavioral characteristics and natural instincts. The release of recommended national standards in the specification can provide some reference for the use of masks and physical properties, as well as the basic safety concepts and the impact of wind hazard.

Generally speaking, a standard from publication to perfection is a long-term process, especially as the "norm" is the world's first. It must undergo a gradual improvement and gradual improvement after publication. It is hoped that consumers will make suggestions and improve the industry and children's mask manufacturers to promote the healthy development of children's mask industry.

Four

Yue Weihua, director of Beijing medical device inspection institute,

Convergence between standards and medical mask standards

Child masks are important products that protect children's health and safety during epidemic or air pollution. The requirement of bacterial filter efficiency for children's sanitary masks is more than 95%. The technical index is derived from the current mandatory pharmaceutical industry standard YY 0469 "medical surgical mask" for the regulation of bacterial filtration efficiency. This index is also used in the European standard EN14683 I and the American Standard ASTM F2100. The index of bacterial filtration efficiency in the child hygiene masks is adopted as an index equivalent to the medical respirator.

The test method of the project is based on Appendix B test method of YY 0469. The test method was used to test the effect of mask on bacteria filtration by measuring the barrier ability of Staphylococcus aureus aerosol with a diameter of 3 microns. This method can effectively verify the ability of children's sanitary masks to prevent saliva, droplets and other large particles from the mouth and nasal cavity, so as to ensure the basic safety of children during daily wear and reduce the infection of common pathogens.

In order to meet the hygienic index in the enterprise production process, the disinfection and sterilization process is often adopted, of which ethylene oxide is a more economical and typical way of disinfection and sterilization. China's current mandatory national standard GB 19083 "medical respirator technical requirements", YY 0469 "medical surgical mask" and other medical mask standards have put forward sterilization requirements for respirators, and require ethylene oxide residue not exceeding 10 g/g. Judging from foreign standards, Japan also does not exceed 10 g/g, and the United States has different regulations on the location of medical devices.

From the perspective of children's health and safety, children's respirators should be sterilized according to medical masks, so as to avoid the lack of cleanliness in the production process and cause bacterial contamination. On the one hand, GB/T 38880-2020 is connected with the requirements of sterilization standard for medical masks, and on the other hand, it greatly improves the requirement of the limit of ethylene oxide residue, and the prescribed limit is not more than 2 g/g. The test method of this project clearly stipulates that according to the GB /T 14233.1-2008 ninth chapter of the medical transfusion transfusion injection apparatus, the gas chromatography method is adopted. The method has high sensitivity, good repeatability and low detection limit.

When the mask is used, the product is placed on the mouth and nose and face. The filtered air enters the respiratory tract directly through the mask, and the face and mask are in a moist and closed environment. Therefore, if there are too many pathogenic microorganisms on the inner surface of the product, it may lead to facial skin infection, respiratory tract infection and so on. According to the GB 15979-2001 "Hygienic standard for disposable sanitary products", the specification clearly requires that pathogens in children's masks should not be detected, and bacteria and fungi should not exceed the standard.

5 Liu Yi, an expert in the children's Hospital Affiliated to the Capital Institute of Pediatrics.

Children's respirators can effectively block the spread of droplets, pollen, dust, microorganisms and other particulates, reduce the concentration of viruses in aerosols, and prevent airborne microbes, dust, droplets, smoke and other particulate matter inhalation.

Children's mental immaturity can not clearly understand the significance of wearing children's masks correctly. Parents and teachers should correctly guide them. They can not reach the goal of wearing children's masks by overdescribing the bad conditions of external environment, which may make children rely too much on the safety feeling of wearing masks, do not remove masks and cause heart and lung function to be affected. In order to reduce the probability of virus passing through the air after class resumption, besides promoting students to wear masks in classrooms, we should emphasize regular ventilation, wash hands frequently and maintain proper social distance, which is also an important measure to prevent virus infection. Parents and teachers should help children with special marks to mark masks to avoid cross infection caused by wrong masks.

6 Liu Taijie, senior engineer of the national ergonomics Standardization Technical Committee: strictly control the head mask technology of children's respirators.

The first standard data of the current "standards" refer to the national standard of GB/T 26160 "minors' head and face size". This standard is based on a large number of data measured by children of different ages and sexes in different regions of China. The facial features of 26 thousand children are collected, which basically represent the characteristics of the head and face of juveniles in China.

The measurement of the head and face of juveniles in China began in 2006. It is a non-contact anthropometric method. The equipment adopted is the most advanced German laser scanner and head scanner in Germany. The measurement method is GB/T 23698. This measurement method is safe and efficient, and can avoid hurting children who are active and active. According to the requirement of measurement, head data acquisition is achieved by non-contact 3D scanning. Before data collection, the child's hair is pressed tightly by the medical net cap according to the standard requirement, so as to ensure the accuracy of the data.