Polyester yarn is a synthetic textile fiber that is commonly used in clothing, upholstery, and other applications. Here is a brief overview of how polyester yarn is made:
1. Polymerization: The first step in making polyester yarn is to polymerize the raw materials. These raw materials usually consist of purified terephthalic acid (PTA) and ethylene glycol. The PTA and ethylene glycol are heated and mixed together in a reactor, which causes them to undergo a chemical reaction called esterification. This produces a liquid polymer that can be further processed into fibers.
2. Extrusion: The liquid polymer is then extruded through a spinneret, which is a device that has small holes in it. The liquid polymer is forced through these holes, and as it exits the spinneret, it solidifies into a long, continuous filament.
3. Drawing: The filament is then stretched or drawn to align the polymer chains and increase the strength of the fiber. This also reduces the diameter of the filament, making it more suitable for use in fabrics.
4. Texturing: The polyester yarn may then be textured to give it more bulk and stretch. This can be done using a variety of techniques, such as air-jet texturing, false-twist texturing, or knit-deknit texturing.
5. Finishing: Finally, the polyester yarn is finished by applying various treatments to improve its appearance and performance. For example, it may be treated with a softening agent to make it feel softer, or with a flame retardant to make it less flammable.
Once the polyester yarn has been made, it can be further processed into a variety of fabrics and other textile products.
