Elastane

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Elastane ( EL ), also spelled elastane , (in the USA and Asia spandex fiber ) is an extremely stretchable chemical fiber with high elasticity, which is spun as filament yarns (mostly as multifilaments, yarn count 11-2 600 dtex) and processed into textile products. The underlying block copolymer has a mass fraction of at least 85% polyurethane . Even when stretched to three times its original length, the fiber returns to almost its original length after the load has been released. It is similar to rubber , but has a higher strength and is more durable.

Ballet dancer in a catsuit

The first fibers made from elastane came onto the market in 1959 as Fiber K after Joseph Shivers developed a process for large-scale production at the American chemical company DuPont . It was glued multifilament yarn made of polyurethane . From 1962, Fiber K was sold in large quantities under the Lycra brand , which has been held in Germany by the Invista company since January 28, 2005 . Two years later, Bayer AG began manufacturing Dorlastan , a multifilament yarn made from polyester urethane. Other brands are creora ( Hyosung ), Linel (Fillattice) and Elaspan (Invista).

Manufacture and construction

The most common manufacturing process for elastane filaments is multi-stage. First, simple linear polyurethanes are formed using the diisocyanate polyaddition process. The production of a polyurethane from butylene glycol and hexamethylene diisocyanate is well suited for fiber production . To form the elastomeric polyurethane block copolymer, a segmented polyurethane, a large part of the glycol is replaced by long-chain dihydroxy compounds (macrodiols) based on polyether or polyester with terminal OH groups during the polyaddition reaction . The macrodiols result in an amorphous structure (the soft segments) and are very mobile under load and are therefore the cause of the very high elongation of a few 100%. If they are converted into macrodiisocyanates (diisocyanate prepolymers) via the terminal OH groups with diisocyanates, these can be chain-extended with short-chain diamines (e.g. ethylenediamine or m-xylylenediamine ) or dialcohols ( ethylene glycol or 1,4-butanediol ) be converted into segmented polyurethanes (block copolymers). The bridges that form within the linear macromolecules between the long-chain soft segments result in the hard segments as short-chain crystalline urea or carbamide structures. They determine the strength and thermal properties of the elastane filaments. The length of the short-chain crystalline area is approx. 2.5–3 nm, that of the “soft” chains approx. 15–30 nm.

properties

  • Density : 1.1-1.3 g / cm 3
  • Maximum tensile force elongation dry equals maximum tensile force elongation wet: 400–700%, combined with a high restoring force that is two to three times higher than that of rubber threads
  • Maximum tensile strength dry: 0.05–0.12  N / tex , which is two to three times higher than that of rubber threads
  • Scuff and abrasion resistance: moderate
  • Moisture absorption: 0.5–1.5%
  • Water retention capacity: 7-11%
  • Can be dyed from aqueous solutions: good with different classes of dyes
  • Melting point: 170-230 ° C
  • Heat resistance up to 120 ° C
  • permanent dimensional stability
  • light, soft, smooth
  • no static charge
  • no pilling
  • Regularly washable up to 40 ° C (recommended), exceptionally also at around 60 ° C

Applications

Elastane is mainly used for clothing that has to be very elastic or a perfect fit. It has therefore established itself primarily in sportswear, underwear and socks. For reasons of comfort, however, it is always mixed with other types of fiber (for example: 80% polyamide , 20% elastane).

Examples of clothing with elastane can be found at:

A special application of elastane takes place in the magician scene: Here elastane fiber is sold as "ultra invisible thread", that is, used as a particularly stretchable, invisible thread.

Web links

Commons : Elastane  - Collection of images, videos and audio files

Individual evidence

  1. ↑ Hans-J. Koslowski: Chemical fiber - Lexicon. 12th, extended edition, Deutscher Fachverlag, Frankfurt am Main 2009, ISBN 978-3-87150-876-9 , p. 69.
  2. ↑ DIN EN ISO 2076, March 2014 edition: Textiles - man-made fibers - generic names. P. 11.
  3. ↑ Trademark register, registration number: 736316
  4. ↑ Trademark register, registration number: 770296
  5. ↑ Trademark register, registration number: 39955281
  6. ↑ trademark register, registration number: 30780515
  7. ↑ Franz Fourné: Synthetic fibers: production, machinery, Features: Manual for system planning, machine design and operation. Carl Hanser Verlag, Munich / Vienna 1995, ISBN 3-446-16058-2 , p. 128.
  8. ↑ Walter Loy: Chemical fibers for technical textile products. 2nd, fundamental revised and expanded edition. Deutscher Fachverlag, Frankfurt am Main 2008, ISBN 978-3-86641-197-5 , p. 62.
  9. ↑ Franz Fourné: Synthetic fibers: production, machinery, Features: Manual for system planning, machine design and operation. Carl Hanser Verlag, Munich / Vienna 1995, ISBN 3-446-16058-2 , p. 129f.
  10. ↑ a b c Wolfgang Bobeth (Ed.): Textile Faserstoffe. Texture and properties . Springer-Verlag, Berlin / Heidelberg / New York 1993, ISBN 3-540-55697-4 , p. 169.
  11. ↑ a b c d e f g Walter Loy: Chemical fibers for technical textile products. 2nd, fundamental revised and expanded edition. Deutscher Fachverlag, Frankfurt am Main 2008, ISBN 978-3-86641-197-5 , p. 63.
  12. ↑ Wolfgang Bobeth (Ed.): Textile fibers. Texture and properties . Springer-Verlag, Berlin / Heidelberg / New York 1993, ISBN 3-540-55697-4 , p. 237.
  13. ^ Kunal Singha: Analysis of Spandex / Cotton Elastomeric Properties: Spinning and Applications. In: International Journal of Composite Materials. 2 (2), 2012, pp. 11–16, doi: 10.5923 / j.cmaterials.20120202.03 .