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Melt Blown Fabric

[Also see my post on Spun Bond Fabric]

Melt blown fabrics have long been used in medicine. These fabrics are best known in the personal protective equipment arena (e.g. masks, gowns, etc.), but they are also known for tissue engineering among other processes. China has a large industry creating this type of fabric technology. But what is “melt blown” fabric?

Melt blown fabric (patented in 1939) is a method of creating a polymer fabric that does not involve knitting or weaving. Instead, the process uses heat or chemicals to form the fabric. Polymer material is heat-treated and extruded through a die. As the polymer material comes out of the die, nano- or microfilaments densely come together in the cooling/blowing process to form a fabric. Non-woven fabric can be produced quickly–5000 meters/minute.

By adjusting the characteristics of the die from which the polymer fibers are extruded, one can customize the fibers produced, such as (but not limited to): fiber diameter, density of fibers, alignment, melt viscosity, elasticity, relaxation time, absorbency, bacterial barrier, cushioning, filtering, flame retardancy, liquid repellency, resilience, softness, sterility, strength, and washability (Jenkins, Meehan, Pourdeyhimi, & Little, 2017; Tan et al., 2010).

Also, different polymers can be used. One such biopolymer is polylactic acid (or polylactide or lactic acid polymer). It is biodegradeable, eco-friendly, non-toxic, high strength profile (as compared to other polymers), high stiffness, and more efficiently produced (Omnexus, n.d.).

With regards to making medical/procedural masks, the outer layer is the liquid/droplet/aerosol barrier layer. The innermost layer (closest to the face) is a moisture-absorber. The middle layer (collection/filtration layer) consists of the melt blown fabric whose fibers range in diameters of 0.1 microns to 15 microns.

https://youtu.be/zHPbJtq4YJc

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