Melt-blown process is a one-step process in which high-velocity air blows a molten thermoplastic resin from an extruder die tip onto a conveyor or take-up screen to form a fine fibrous and self-bonding web. The fibres in the melt blown web are laid together by a combination of entanglement and cohesive sticking. The ability to form a web directly from a molten polymer without controlled stretching gives melt blown technology a distinct cost advantage over other systems.
Melt blown webs offer a wide range of product characteristics such as random fibre orientation, low to moderate web strength. About 40% of melt blown material is used in the uncombined (monolithic) state. The remainder of melt blown materials are composites or laminates of melt blown webs with another material or nonwoven. The largest end-uses for monolithic melt blown materials are oilsorbents, air and liquid filtration media.
The principles and sketches of the different melt blown technologies is shown as above figure. The hot air temperature is close to the used melt temperature. The achieved filament diameter is one magnitude lower compared to the spunlaid process, 1–5 μm. The calculated filament speed out of throughput and measured filament diameter is resulting in filament speed higher than sonic speed.
