Low-viscosity polymer, usually high-MFR polypropylene, is extruded through a single row of holes and stretched by converging jets of hot air into fibers of about 1 to 5 micrometers, which land on a collector belt or drum. The web is weak but has very small pores and a huge surface area, so it delivers filtration and liquid barrier. Die-to-collector distance, air flow and throughput per hole set fiber size, loft and defects such as shot.
Meltblown layer is only 2 gsm in this SMS, so a little shot shows up straight away as low hydrohead.
Meltblown die tips are fragile precision parts; one dropped wrench or a hard scrape can ruin a die worth more than a car.
Also heard as
- melt-blown
- MB
- meltblowing
Related terms
SMS
Spunbond-meltblown-spunbond: a three-layer composite of strong spunbond outer layers around a meltblown barrier core.
Shot
Small beads or lumps of polymer that failed to form fibers and sit embedded in a meltblown web.
Electret
Filter fabric, usually meltblown, carrying a long-lasting electrostatic charge that pulls particles out of the air.
Melt flow rate
Grams of molten polymer pushed through a standard die in 10 minutes, the basic measure of how easily a resin flows.
Hydrohead
Shop and spec clip for hydrostatic head: the water pressure a fabric holds before water comes through.