How Are Surgical Masks Made?

Medical surgical masks are made of non-woven fabrics, which have better bacteria filtration and breathability, and are smoother than woven fabrics. The most commonly used material is polypropylene with a density of 20 or 25 grams per square meter. Masks can also be made of polystyrene, polycarbonate, polyethylene or polyester.

The 20 gsm mask material is made by a spunbond process, which includes extruding molten plastic onto a conveyor belt. The material is extruded into a web, and when they cool, the wires are connected to each other. 25 gsm fabric is made by melt-blowing technology, which is a similar process. The plastic is extruded through a mold with hundreds of small nozzles, and then blown into tiny fibers by hot air, cooled again and bound to a conveyor belt.

Medical masks consist of a multilayer structure, usually covered with a layer of non-woven fabric on both sides of the mask. Non-wovens are made from three or four layers of material. Due to its disposable properties,non-woven fabrics have lower manufacturing costs and are cleaner. These disposable masks usually have two filter layers, which can filter out particles such as bacteria above 1 micron. However, the filtering level of a mask depends on the fiber, the manufacturing method, the cobweb structure, and the cross-sectional shape of the fiber. Masks are manufactured on a production line that will be assembled with spools of non-woven fabric. These layers are welded together using ultrasound, and the mask is stamped with a noseband, earrings, and other parts.

The respirator also has multiple layers. The outer layer on both sides is a protective non-woven fabric with a density between 20 and 50 grams per square meter, which can block both the external environment and the wearer's own breath. This is followed by a pre-filtration layer with a density of up to 250 g / m2. This is usually a needle-punched non-woven fabric that is produced by hot calendering, in which plastic fibers are thermally bonded by high-pressure heated rollers. This makes the pre-filtration layer thicker and stiffer to form the desired shape and keeps it used as a mask. The last layer is the highly efficient electret non-woven material, which determines the filtration efficiency.

Finished masks and respirators must be disinfected before leaving the factory.