Download - Manufacturing Processes for Synthetic Fibers
Manufacturing Processes For
Synthetic Fibers
About half of the textiles produced in the world are made from man-made fibers.
Despite questions of aesthetics and taste, there should continue to be a significant demand for synthetic fibers, in large part because these fibers can be “tailor-made” to provide specific properties that natural fibers cannot provide.
IntroductionIntroduction
When the filaments emerge from the holes in the spinneret, the liquid polymer is converted first to a rubbery state and then solidified. This process of extrusion and solidification of endless filaments is called Spinning.
Spinning
Classifying Synthetic Fiber Manufacturing Processes
Spinning
Melt Solution
In their initial state, the fiber-forming polymers are solids and therefore must be first converted into a fluid state for extrusion. This is usually achieved by melting, if the polymers are thermoplastic synthetics (i.e., they soften and melt when heated), or by dissolving them in a suitable solvent if they are non-thermoplastic cellulosics.
Melt spinning is the preferred method for polymeric fibers.
Melt Spinning is simple and highly productive method.
Low-speed winder (up to 2500 m/min)
High-speed winder (up to 6000 m/min)
Melt Spinning
Nylon, Polyester
Olefin, Sulfar
Wet spinning is the oldest and the most complex process.
The spinnerets are submerged in a chemical bath and as the filaments emerge they precipitate from solution and solidify.
It is a low speed (150 m/min) process hence to increase the productivity Spinneret holes are increased.
Wet Spinning
Acrylics, Rayon
Spandex, Aramids
Dry Spinning is also used for fiber-forming substances in 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.
Dry Spinning
Acetate, Triacetate
Acrylics, Vinyon
Melter
Metering Pump
Filter
Spinneret
Quench
Finish Applicator
Parts Of Melt Spinning Machine
Solution Vessel
Feed Vessel
Heat Exchanger
Metering Pump
Filter
Spinneret
Spin Bath(Wet), Spin Cabinet(Dry)
Winding
Parts of Wet and Dry Spinning Machine
The spinnerets used in the production of most manufactured fibers are similar, in principle, to a bathroom shower head.
Spinneret may have from one to several hundred holes.
The tiny openings are very sensitive to impurities and corrosion.
The liquid feeding them must be carefully filtered.
Maintenance is also critical.
Spinnerets
Spinnerets And Shapes Obtained
> No solvent
recovery.> High Speed
> Simple>
Inexpensive
> Solvent Recovery> Slowest Process
> Additives can be added
> Solvent Recovery> Lower Speeds
> Limited use due to
environmental concerns
Comparison
Melt Wet Dry
Thank You