Meltblown fabrics

Fig. 11. Flow sheet for typical meltblown fabric manufacture.

In the manufacture of meltblown fabrics, a special die is used in which heated, pressurized air attenuates the molten polymer filament as it exits the orifice of the dye or nozzle (Fig. 9). Air temperatures range from 260—480°C with sonic velocity flow rates (43). 

Meldrum s acid chemistry, 21 151,152, 153 Melengesterol acetate (MGA), 10 871 Melissic acid, physical properties, 5 30t Melt behavior, of polycarbonates, 19 805 Meltblown fabrics, 17 478-479, 495 Meltblown fibers, 11 237, 240-241 Melt casting, 14 230 Melt crystallization, 3 137—141... 

Melt-blown fibers have considerable use in disposable diapers for babies and adults, sanitary napkins, feminine hygiene, etc., since eliminating plastic backsheets, integrating wicking layers and standing leg cuffs requires the use of meltblown fabrics. 

Meltblown fabrics are also made directly from thermoplastic resins. Polymer granules are melted and extruded. As soon as the melt passes through the extrusion orifice, it is blown with air at high temperature. The airstreams attenuate the molten polymer and solidify it into a random array of very fine fibers. The fibers are then separated from the air stream as a randomly entangled web and compressed between heated rolls. The combination of fine-diameter fibers, random entanglement, and close packing results in a fabric structure with a large surface area and many small pores. 

Spunbondeds are commonly used for coverstock, geotextiles, roofing substrates, carpet-backing, medical products, filtration, fiimiture, and packaging. Meltblown fabrics, because of their relatively fine fiber structure, is commonly used in filtration, sorbents, wipes, and sanitary products. 

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