Elastane also known with its trade names, Lycra, Spandex, Dorlastan etc is a synthetic fiber. Elastane fibers have properties that are not present in nature, the most important being its exceptional elasticity. The trade names of elastane are Spandex (North America) Lycra (Britain), Elastane (Europe).
RAW MATERIALS AND CHEMICAL COMPOSITION:
A stretchable spandex fiber is produced with variety of raw materials. Firstly a pre polymer is formed by reaction between diisocyanates and poly ether polyols which acts as an important element for fiber formation. To this stabilizers and other chemical colorants are also added. The common di-isocyanates used to create prepolymer are Methylene di-isocyanate (MDI), 2,6-Toulene di-isocyanate (2,6-TDI), 2,4-Toulene di-isocyanate (2,4-TDI). MDI AND 2,4-TDI are hazardous air pollutants whereas 2,6 TDI is not. Polyether polyols can be polyester or polyethers or a combination of both. The condition during reaction has to be maintained optimum, otherwise results in side reactions forming insoluble cross linked polymers. If the polymers are insoluble in nature they cannot be spun.
To produce a segmented polyurethane, the extenders i.e., diols or diamines are used to polymerize the pre-polymer. Thus the spandex produces through two step synthesis process.
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About the Authors:
Ayodya Kavitha, Surekha and Sahithi are associated with the University College of Technology, O.U.