Similarities and Differences between Melt blown Fiber Nonwovens and Spunbond Method

Meltblown method is also one of the direct polymer netting methods, it is the polymer melt extruded from the screw extruder through the high speed high temperature airflow blowing or other means to make the melt fine stream by extreme stretching and formation of very fine fibers, and then gathered to the netting roller or netting curtain to form a fiber network, and finally reinforced by the self-bonding effect to make melt blown fiber nonwoven fabric.

Meltblown fiber forming principle

1. Similarities and differences with spunbond method

Spunbond method is also called spunbond direct fabric method, it is the use of melt spinning and other methods of polymer slices by melt spinning and stretching to form a continuous filament to lay the network, and then by bonding, finishing and other processes to make products

Similarities

① Polymers are extruded from the spinnerets in the molten state

② The web can be reinforced by thermal bonding (surface bonding or spot bonding) or by its own bonding into nonwoven fabric.

 Differences

①In spunbonding method: cooling by cold air and stretching at the same time to form a continuous filament, which is laid onto a net curtain

Meltblown method: High-speed hot air blowing, subject to extreme stretching, forming ultra-fine short fibers, flying at very high speed to form a web curtain or condensation roller to form a fibrous web

②Spunbonding method: the fiber network reinforcement methods, in addition to thermal bonding, but also can take a variety of needle punching, hydroentanglement, chemical bonding and other means

Melt spray method: mainly rely on thermal bonding or their own bonding

2. Traditional process flow

Polymer feeding → melt extrusion → fiber formation → fiber cooling → into a network → bonding (solid network) → cutting edge winding → finishing or special finishing

-Polymer feeding -- Polymer is generally made into small spherical or granular slices, which are poured into a drum or hopper and fed into a screw extruder

-Melt extrusion -- At the feed end of the screw extruder, polymer chips are mixed with additives such as stabilizers, whitening agents and other necessary raw materials such as masterbatches, after thorough mixing into the screw extruder, heated into a melt, and finally the melt is fed into the spinneret by a metering pump through a filter. In the meltblown process, the general extruder also uses its shearing action and thermal degradation to reduce the molecular weight of the polymer.

-Fiber Formation - The filtered clean melt is passed through a distribution system and then fed uniformly into each group of spinnerets so that each spinneret has a consistent amount of extrusion. The spinnerets for meltblown fibers differ from other spinning formation methods in that the spinneret holes must be lined up in a straight line with high velocity airflow ejection holes on the top and bottom sides.

-Fiber cooling - A large amount of room temperature air is drawn in on both sides of the spinneret at the same time, mixing with the hot air stream containing the microfiber to cool it down, and the molten microfiber cools and solidifies.

-Into the net - In meltblown fiber nonwoven production, the spinneret can be placed horizontally or vertically. If placed horizontally, the microfibers are sprayed onto a circular collection drum to form a web; if placed vertically, the fibers fall onto a horizontally moving webbing curtain to coalesce into a web.

-Bonding (web consolidation) - The self-bonding consolidation discussed above is sufficient for some applications of meltblown fabrics, such as those requiring a fluffy structure, good air retention or void ratio. For many other applications, self-adhesive reinforcement alone is not sufficient, but hot-rolled bonding, ultrasonic bonding or other reinforcement is also required.

3. Characteristics of meltblown fiber nonwoven process

(1) Short process flow and high production efficiency.

(2) Very fine fibers, good uniformity of fiber network, soft handfeel, outstanding advantages in filtration, antibacterial and adsorption.

(3) Poor fiber orientation and low strength of the fiber network.

(4) High energy consumption.

(4) The information is provided by meltblown fiber supplier.