Polymer feeding→melt extrusion→fiber formation→fiber cooling→web forming→bonding (fixed web)→trimming and winding→after finishing or special finishing
Polymer feeding-PP polymer raw materials are generally made into small spherical or granular slices, poured into a barrel or hopper, and fed into the screw extruder.
Melt extrusion—— At the feed end of the screw extruder, the polymer chips should be mixed with stabilizers, brighteners and other additives and necessary raw materials such as masterbatch, and then enter the screw extruder after being fully stirred and mixed, and heated at high temperature. Become a melt, and finally the melt is sent to the spinneret by the metering pump through the filter. In the melt blown process, the general extruder also uses its shearing and thermal degradation effects to reduce the molecular weight of the polymer.
Fiber formation-the filtered clean melt will pass through the distribution system, and then evenly sent to each group of spinnerets, so that the extrusion volume of each spinneret hole is consistent. The spinneret of meltblown fiber is different from other spinning methods. The spinneret holes must be arranged in a straight line, and the upper and lower sides have high-speed air jet holes.
Fiber cooling-a large amount of room temperature air is sucked in at the same time on both sides of the spinneret, mixed with the hot air stream containing ultra-fine fibers to cool it down, and the molten ultra-fine fibers are cooled and solidified.
Netting——In the production of meltblown fiber nonwoven fabric, the spinneret can be placed horizontally or vertically. If placed horizontally, the superfine fibers are sprayed on a circular collecting drum to form a web; if placed vertically, the fibers fall onto a horizontally moving web forming curtain to condense into a web.
Adhesion (fixed net)-the self-adhesive reinforcement mentioned above is sufficient for some applications of melt blown cloth, such as: the fiber net is required to have a relatively fluffy structure, good air retention rate or porosity Wait. For many other applications, self-adhesive reinforcement alone is not enough. Hot-rolling bonding, ultrasonic bonding, or other reinforcement methods are also required.
