1. Mask division

The production of masks has been hot for a few months, but the foreign epidemic situation has not weakened. Therefore, there is still a lot of room for the demand for masks. Therefore, we have accumulated a lot of experience in mask production.

Faced with the new coronavirus epidemic, masks have become a necessity in life. What is the difference between N95 masks, KN95 masks, medical protective masks, and disposable medical masks? Can foreign imported and aided masks be applicable?

These classification standards are mainly classified according to the filtration efficiency. According to the scope of application and technical requirements of various mask standards, masks can be divided into ordinary masks (ordinary protective masks and daily protective masks) and medical masks (medical general masks and medical protective masks), and all kinds of masks are classified according to their protection levels For the third level.

They are classified into three levels: medical protective masks, general protective masks, and general medical masks. In summary, ordinary masks in various countries are concerned about the filtration efficiency of particulate matter (oily and non-oily).

Among them, N95, KN95, and FFP2 are all codes for filtration efficiency. In addition to the filtration efficiency of particulate matter, medical masks also pay attention to indicators such as microbial indicators, ethylene oxide residues, and flame retardancy.

However, it cannot be simply considered that medical masks are more protective than ordinary masks. Disposable medical masks do not specify the filtration efficiency of particulate matter, which is lower than the 95% filtration efficiency of KN95.

2. China's mask standards

China's general mask standard mainly implements two national standards: including GB2626-2006 "Respiratory Protective Equipment Self-priming Filtered Particle Respirator" under the jurisdiction of the National Technical Committee for Standardization of Personal Protective Equipment.

GB/T32610-2016 "Technical Specifications for Daily Protective Masks" under the jurisdiction of the National Textile Standardization Technical Committee.

GB 2626-2006 "Respiratory protective equipment self-priming filter anti-particulate respirator"

(1) Standard source

This standard is a mandatory national standard, proposed by the State Administration of Work Safety and under the jurisdiction of the National Standardization Technical Committee for Personal Protective Equipment (SAC/TC 112).

(2) Technical content

From the perspective of the scope of application, this standard applies to ordinary self-priming filter respiratory protective equipment that protects various particulate matter, and other special environments (such as hypoxic environments, underwater operations, etc.) are not applicable.

From the perspective of the definition of particulate matter, this standard defines various forms of particulate matter, including dust, smoke, fog, and microorganisms, but does not define the size of particulate matter. From the perspective of filter element level,

It can be divided into KN type for filtering non-oily particles and KP type for filtering oily and non-oily particles, and this is the mark.

The core of the mask standard approval is the filter material. As the heart and lungs of the mask, "melt blown cloth" must be strictly controlled in quality.

3. Factors affecting the quality of meltblown cloth

The main factors affecting the quality of meltblown cloth are hardware equipment, raw materials, production environment, and production process.

The hardware equipment for the production of melt blown cloth mainly includes melt blown cloth production equipment, which is a melt blown machine or melt blown cloth production line equipment. The melt blown cloth production line consists of the following parts:

Screw extruder: melt the slices.

Metering pump: Control the output and fiber fineness to continuously deliver the melt to the spinneret.

Melt filter: filter the impurities in the melt.

Conveying net curtain: make melt blown fiber evenly received and spread on the net

Spinning box: After the fiber is ejected, high-speed hot air can be used for air-stretching to blow the fiber off and become superfine fiber.

Feeding system: It consists of 3 measuring hoppers, which are used to measure white slices, masterbatch, and additives.

Hot air blower and heater: provide the temperature and pressure of the hot air used in the spinning air stretching, use electricity for heating, and consume a lot of power.

Coiling machine: adopts fully automatic coiling to pack meltblown cloth into rolls.

Air compressor complete system: An air compressor is often used to supply air to it in order to stretch the fiber, so that the fiber can reach a certain fineness.

The improper selection of the air compressor will not only affect the fineness of the drawn fiber, but also need to clean the gas. If the oil lubrication air compressor system is used, it must be degreasing treatment (recommended catalytic degreasing device is relatively more stable),

Otherwise it will eventually affect the performance of the filter product.

Raw material: The raw material of melt blown cloth is generally polypropylene. The melt blown cloth is mainly made of polypropylene, and the fiber diameter can reach 1 to 5 microns. Many voids, fluffy structure, good anti-wrinkle ability.

The ultra-fine fiber with unique capillary structure increases the number and surface area of ​​the fiber per unit area, so that the meltblown cloth has good filterability, shielding, heat insulation and oil absorption.

It can be used in air, liquid filter materials, isolation materials, absorbing materials, mask materials, thermal insulation materials, oil absorbing materials and wipe cloths.

Melt blown cloth production environment: to build a melt blown cloth purification workshop, choose one hundred thousand grade purification workshop or 300 thousand grade purification workshop.

Melt blown cloth production process:

The melt-blown non-woven process uses high-speed hot air to stretch the thin stream of polymer melt extruded from the orifice of the die, thereby forming ultra-fine fibers and condensing on the curtain or roller, and relying on self-bonding And become a non-woven fabric.

Therefore, in the entire production process of meltblown cloth, every link is very important, especially hardware equipment. Many manufacturers buy unqualified equipment, such as air compressors, in order to save costs. In order to save costs, many purchase oil-lubricated air compressors. No post-treatment of gas

This will cause the gas with high oil and water content to be brought into the production gas, which will ultimately affect the performance and quality of the meltblown cloth and reduce the oil absorption and filtration performance of the mask. In addition to raw materials and processes, it is particularly important that the production environment is controllable. The production environment of some small workshops is quite poor.

Failure to clean up will directly affect the quality of the meltblown cloth. Therefore, every link must be paid attention to in order to better protect people's lives and health, especially for the frontline personnel on the epidemic prevention front.