The new crown epidemic has been more than a year. The national epidemic prevention and control situation is smooth, but the situation of "external input, internal rebound" is still serious, and various epidemic prevention and control measures should continue to stick! Do a good job of protection, stick to wear masks, still the weight of our epidemic prevention!

According to the official website of the State Food and Drug Administration, the packaging does not meet the requirements, Hebei Medical Devices Co., Ltd. has conducted a medical surgical mask, medical mask, medical protective mask, and the recall level is a three-level recall.

The recall involving 111,739,000 sales in China, 51,8050 medical masks, 342,700 medical surgical masks, 256,640 medical protective masks, currently recalled 173,350.

What kind of mask is it effective? Xiaobian Today is coming to you today:

01 What is the standard of a non-woven mask?

We all know that the core material of the mask is the meltblown nonwoven fabric. The quality of the good meltblown nonwoven mask is generally not too bad. It is used for filtration, the basic principle of isolation is mainly adsorbed by fibers to the particles, not blocking. . The test report of the meltblown nonwoven fabric is usually taken by respiratory resistance testing, filtration efficiency testing, microbial testing and three other items. If you want to produce a mask, it should first test whether the meltblown nonwoven fabric is qualified, so that the meltblown nonwoven fabric will not fail, resulting in unqualified mask production, then this will be a loss.

02 principle of three-layer mask filter particle

The masks we use are usually 3 floors and above. Internal and external materials, mainly polypropylene spunbond nonwoven materials, which are limited by particle filtering efficiency. The intermediate layer functions together with the electret polypropylene meltblown nonwoven material to particle filtration, the material can utilize electrostatic adsorption particles, thereby greatly improving the filtration efficiency.

The filtration of particulate matter is mainly gravity settling, interception, inertial collision, diffusion, electrostatic adsorption, and the like. Under the common action of various filtration mechanisms, there is an aerodynamic particle diameter of about 0.3 μm, and is generally referred to as a minimally penetrating particle size (MPPS).

The main filtering mechanism of the three-layer mask is as follows:

1 Diffusion deposition: brown particles adsorbed by molecular weight when filtered. The particles that are most likely to capture small size particles, fine fibers, and low speed movement.

2 Residual sediment: the mechanical screening of the smaller particles moving with the gas stream is intercepted.

3 inertial deposition: When the particles are hit by the web of the material, filter fibers are hit by inertia, they are detached from the airflow and captured by molecular gravity. Large particles, high density, and fast speed have good interception.

4 Electrostatic attract deposition: The particles are deposited by the electrostatic action of the filtration fibers. The smaller the particles, the stronger the deposition effect of 1 and 4, the larger the particles, the better the effects of 2 and 3, the smaller the particles, the greater the difficulty of filtration. Combined with the synergistic effects of four filtering mechanisms, for common mechanical media, the most easily penetrated particle diameter is 0.1 μm to 0.3 μm.

03 main test items for meltblown non-woven masks

The meltblown nonwoven fabric has a thinner fiber structure than the spunbond nonwoven fabric, and thus has better capture performance for fine particles. The use of meltblown nonwoven fabric has good processability, excellent chemical polypropylene is raw material, preferably filtration efficiency, excellent thermal insulation performance, and high porosity and good gas permeability. The main test properties are as follows.

1. Appearance quality inspection: holes, impurities, odors, micro holes, crystallization points, melt, hard lines, unstressed areas, sparse grid, width deviation, chromatic aberration, joint quality.

2. Intrinsic quality test: the mass deviation rate of the unit area, longitudinal breakage strength, lateral breakage strength, longitudinal and lateral fracture elongation, hydrostatic pressure, permeability.

3. Microbiological indicators Test: Total bacteria, total fungus, coliform, pathogenic sepsis bacteria.

04

Sample of meltblown nonwoven fabrication does not meet standard test

1. Raw materials do not meet the standard

The melt flow rate of the tropical region is high, the fluidity is stable, and the meltblown polypropylene is basically supplying a large number of manufacturers, and the market is difficult to buy. However, some manufacturers will purchase ordinary polypropylene and produce meltblown nonwoven fabrics through some processes. The biggest problem of ordinary polypropylene is that it may cause melt fluid flow uneven, and some excessive drafting, this is easy to cause the particulate (block polymer), so that the fiber thickness is uneven, and affects the gas permeable of the meltblown nonwoven fabric Sex and filterability. Most low-end meltblown nonwoven fabric production lines are not electrostatic electret processing processes, the highest filtration efficiency is only about 60%.

2. Melting nonwoven fabric production process parameter setting does not meet the standard

The meltblown nonwoven fabric is made of meltblown polypropylene, is plasticized and melted, and the filaments are ejected at high temperatures and high speeds, naturally cooled in the air.

The size of the extruder equipment affects the production width and efficiency of the melting cloth. The quality of the die can be sprayed, the roller, the transformer is best to choose a good; of course, the mold, melt temperature, air volume, wind speed, and electrostatic erased body, etc., can also affect the melting cloth. quality. The raw materials, equipment and process parameters are well controlled, and small meltblown equipment can still produce 95% and 99% of meltblown woven fabric.

3. Filtration of the molten non-woven fabric does not meet the standard

Typically, there is a problem in the presence of the electrostatic eradicate process during the production process of the meltblown nonwoven fabric, resulting in the static adhesive of the meltblown nonwoven fabric. The structure of the meltblown non-woven fabric is very simple, like a fishnet, the gap of the meltblown nonwoven fabric is actually much larger than the virus, the virus is about 0.1 um, the sling of the non-woven fabric is 1 um, even more, but being Blocking without cauming. This also depends on the integration of these theories.

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Now everyone will have a further understanding of the meltblown non-woven fabric, which is aware that the effective protective mask can greatly prevent and reduce the risk of new coronavirological pneumonia infections. It can reduce the amount of foam, the injection speed, and can block a foam containing the virus, prevent the wearer from inhaling, reducing the risk of infection.

The protective mask includes a variety of types. When choosing, pay attention to select the appropriate type, and our Yancheng Ruize Color Parent Co., Ltd. specializes in producing the elective armor and meltblower for the producing meltblown. Since its inception, we have always adhered to the "pursuit of the ultimate and strive of perfection", which is committed to the application of medical care, health nonwoven fabric, etc. The quality is stable and reliable, the technology is advanced, and it is well received by customers. Yancheng Ruize color masterbatch is worthy of your trust!