INTRODUCTION:


Elastanealso known with its trade names, Lycra, Spandex, Dorlastan etc is a syntheticfiber. Elastane fibers have properties that are not present in nature, themost important being its exceptional elasticity. The trade names of elastane areSpandex (North America) Lycra (Britain), Elastane (Europe).


RAW MATERIALS AND CHEMICAL COMPOSITION:


Astretchable spandex fiber is produced with variety of raw materials. Firstly apre polymer is formed by reaction between diisocyanates and poly ether polyols whichacts as an important element for fiber formation. To this stabilizers and otherchemical colorants are also added. The common di-isocyanates used to createprepolymer 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 airpollutants whereas 2,6 TDI is not. Polyether polyols can be polyester or polyethersor a combination of both. The condition during reaction has to be maintainedoptimum, otherwise results in side reactions forming insoluble cross linkedpolymers. If the polymers are insoluble in nature they cannot be spun.


MANUFACTURING PROCESS:


Toproduce a segmented polyurethane, the extenders i.e., diols or diamines areused to polymerize the pre-polymer. Thus the spandex produces through two stepsynthesis process.


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About the Authors:


Ayodya Kavitha, Surekhaand Sahithi are associated with the University College of Technology, O.U.