Meltblown non-woven fabrics are mainly used to filter micron-level particles such as dust, microorganisms, smog, etc., and can be called the "heart" of masks . The polypropylene ultrafine fibers are randomly distributed and bound together. The appearance is white, smooth, and soft. The material fiber fineness is 0.5-1.0 microns. The random distribution of fibers provides more opportunities for thermal bonding between fibers, thus making melt blowing The gas filter material has a larger specific surface area and a higher porosity (≥75%). After high-voltage electret electrostatic treatment, it has the characteristics of low resistance, high efficiency and high dust capacity.
Alias: meltblown cloth, mask cloth, PP non-woven fabric
Raw materials: plastic polypropylene (PP) meltblown special materials
Meltblown nonwoven fabric is a kind of non-woven fabric with static electricity. Meltblown is a conventional manufacturing method for micrometer and nanofibers. The polypropylene polymer solution is extruded with ultra-fine polypropylene short fibers with a diameter of 0.5-1.0 microns by a high-speed small nozzle.
The unique capillary structure of melt-blown non-woven fabric increases the number and surface area of fibers per unit area, and the gap is extremely fine. Through high-voltage electret electrostatic treatment, the fiber has electrostatic adsorption capacity, which has good air filterability.
Image screenshot from clip video
The filtering effect of the melt-blown non-woven fabric is a "smile curve". Nano-sized non-oily particles with a diameter of less than 0.1 microns can be adsorbed by static electricity . Particles with a diameter greater than 10 microns can be absorbed by the physical structure of the fabric. Even the worst gauze mask can achieve a protection rate of nearly 80%.
The most difficult to filter are particles with a diameter in the range of 0.3 microns. Therefore, China's testing standards for masks use 0.3 micron sodium chloride particles as the testing index. The melt-blown non-woven fabric with a thickness of less than 0.1 mm can filter 0.3 micron sodium chloride particles by more than 70%.
The virus exists in the form of droplets and aerosol droplet nuclei, of which 82% of the droplet nuclei have a diameter in the range of 0.74 to 2.12 microns. Therefore, melt-blown non-woven fabrics have become core materials such as masks and HEPA filter paper, which can effectively prevent viruses and play an irreplaceable role in the medical and health fields.
Medical masks generally use SMS (spunbond-meltblown-spunbond) composite multi-layer structure. S inside and outside is spunbond nonwoven fabric, English is Spunbond; middle M is meltblown nonwoven fabric, English is Melt blowing.
The outer layers of medical surgical masks and medical N95 masks need to use waterproof non-woven fabrics, which are mainly used to isolate patients' droplets and blood; the middle of medical N95 masks is a thicker melt-blown non-woven fabric with Good filterability, the inner layer is ordinary non-woven fabric.
The filter layers of industrial dust masks are mostly melt-blown non-woven fabrics or HEPA filter papers made of melt-blown non-woven fabrics.
The filter cotton and electrostatic cotton of the gas mask also use melt-blown non-woven fabric, and the high-end dust box uses the HEPA filter element.
The weight range of melt-blown non-woven fabrics is generally 15-500 g / m2, and the melt-blown non-woven fabrics used in masks are light and thin. As a comparison, the T-shirt we wear in summer weighs about 150 grams. The thickness of the melt-blown non-woven fabric is very important for masks with different filtration levels.
20 ~ 25 grams weight: BFE≥95, medical surgical mask standard is BFE≥95% (antibacterial), PFE≥30% (antivirus)
40 ~ 45 grams weight: National standard KN90 mask
50 ~ 55 grams weight: National standard KN95, American standard N95 mask
75 ~ 90g weight: National standard KN100, American standard N99 mask