Wet Spinning :
Wet spinning is the oldest process. It is used for fiber-forming substances that have been dissolved in a solvent. The spinnerets are submerged in a chemical both and as the filaments emerge they precipitate from solution and solidify. Because the solution is extruded directly into the precipitating liquid, this process for making fibers is called wet spinning. Acrylic, rayon, aramid, modacrylic and spandex can be produced by process.
Dry Spinning :
Dry spinning is also used for fiber -forming is solution. However, instead of precipitating the polymer by dilution or chemical reaction., solidification is achieved by evaporating the solvent in a stream of air or inert gas.
The filaments do not come in contact with a precipitating liquid, eliminating the need the drying and easing solvent recovery. This process may be used for the production of acetate, triacetate, acrylic, modacrylic, PBI, spandex, and vinyon.
Melt Spinning :
In melt spinning, the fiber-forming substance is melted for extrusion through the spinneret and then directly solidified by cooling. Nylon, olefin, polyester, saran, and sulphur are produced in this manner. Melt spun fibers can be extruded from the spinneret in different cross-sectiona shapes ( round, trilobal, pentagonal, octagonal, and others ). Trilobal-shaped fibers reflect more light and give an attrative sparkle to textiles.
Gel Spinning :
Gel spinning is a special process used to obtain high strength or other special fiber properties. The polymer is not in a true liquid state during extrusion. Not completely separated as they would be in a true solution, the polymer chains are bound together at various points in liquid crystal form. This produces strong inter-chain forces in the resulting filaments that can significantly increase the tensile strength of the fibers.
The filaments emerge with an unusually high degree of orientation relative to each other further enhancing strength. The process can also be described as dry-wet spinning, since the filaments first pass through air and then are cooled further in a liquid bath . Some high-strength polyethylene and aramid fibers are produced by gel spinning.
To be continue.......