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Nonwovens: the primary material component of PPE
According to the European Disposables and Nonwovens Association, nonwovens are innovative, high-tech, engineered fabrics made from fibers that are used in a wide range of consumer and industrial products.1Get more news about sms nonwoven fabric seller,you can vist our website!
The expensive machinery that produces these products works by melting polypropylene pellets and injecting the liquid through tiny holes to make micron-sized threads. These threads congeal and are converted into a featherweight nonwoven fabric that can trap microscopic particles and droplets.2
Nonwovens are extensively used in the medical field, since their critical safety properties provide protection against infections and diseases. Nonwovens play a vital role in the fight against cross-contamination and the spread of infectious strains of bacteria and viruses.3
Spunbond/melt blown/spunbond (SMS), a primary nonwoven tri-laminate material used in the manufacture of PPE, consists of a middle layer of melt blown polypropylene fabric thermally sandwiched between two layers of spunbond polypropylene fabric. Each of these individually manufactured fabric layers’ properties contribute to the overall SMS end product. When combined, these two nonwoven fabrics provide water resistance as well as breathability and comfort.4
The spunbond process converts melted polypropylene granules into nonwoven fiber. The fabric is produced by depositing extruded, spun filaments onto a collecting belt.5 This is followed by the bonding process, which imparts strength and integrity to the web by applying heated rolls to partially melt the polymer and fuse the fibers. Compared with melt blown fabrics, spunbond fabrics contain coarser fibers and a much greater tensile strength.6
The one-step melt blown process, similar to the spunbond process, converts melted polypropylene granules into a low-diameter nonwoven fiber web. Extruded filaments are attenuated using high-velocity hot air streams; these impinge on the filaments as they emerge from extrusion nozzles, enabling much finer filaments to be obtained.7
The melt blown process is the only large-scale commercial process currently being used to produce melt-spun fibers that have diameters in the submicron range, without splitting or chemically dissolving away polymer. It is used to create nonwoven fabrics of various widths and thicknesses on large rolls.
Melt blown fabrics are composed of submicron filaments that have a large variation in diameter and therefore have superior filtration properties compared with spunbond fabrics.7 Figure 1 shows how the melt blown process is used to create fabric for medical masks.