Non-woven fabric according to the web forming process
Non-woven fabrics are divided into:
①. Spinning into a network
Spinning into a network process principle: polymer slices are fed into a screw extruder, After being melted, extruded, filtered and metered, it is sprayed out from the spinneret hole. After the filament bundle is cooled and drawn by the air flow, it is evenly laid on the condensing screen curtain, and the formed filament fiber web is thermally bonded, chemically After bonding or needle punching, it becomes a spunlaid nonwoven material.
②、Airlaid
Fibers are opened, impurity-removed, mixed and then fed to the main carding mechanism. After further carding, the fibers are in a single-fiber state, and are rotated at high speed in the cylinder Under the combined action of the centrifugal force and the air flow, the fibers fall off the sawtooth of the card clothing, and are gathered on the web curtain by the air conveying disease, forming a fiber web with three-dimensionally disordered arrangement of fibers.
③. Carding into a web
After the raw material is opened by the opening machine, there are still fiber lumps or fiber bundles, and the arrangement of the fibers is also disordered. The task of the carding machine is to further loosen the fiber aggregates after opening, improve the separation degree of the fibers on the premise of reducing fiber damage as much as possible, so that the fiber bundles can be more perfectly divided into single fiber states, and the fibers can be further improved. Mix well and evenly.
④、Electrospinning
Electrospinning is a special form of electrostatic atomization of polymer fluids. At this time, the atomized substances are not tiny droplets, but polymers The tiny jets, which can travel considerable distances, eventually solidify into fibers. Electrospinning is a special fiber manufacturing process in which a polymer solution or melt is jet-spun in a strong electric field. Under the action of the electric field, the droplet at the needle changes from a spherical shape to a conical shape (that is, a 'Taylor cone') and extends from the tip of the cone to obtain fiber filaments. In this way, polymer filaments with nanometer diameters can be produced.
⑤、Flash evaporation method
The flash evaporation method, also known as the instantaneous solvent volatilization method, adopts the dry spinning technology instead of melt spinning. That is, the high polymer is dissolved in a certain solvent to make a spinning solution, and then sprayed from the spinneret hole, and the high polymer is re-solidified into fibers due to the rapid volatilization of the solvent. At the same time, the dry spinning technology used in the flash method is different from the ordinary dry spinning. ejected. Due to the viscosity and fluidity of the solution, the liquid strands solidify in high-speed motion to form extremely fine fiber strands, which are finally adsorbed on the web-forming curtain to directly form a web.
