Elastane

Polyurethane elastomeric fibers17 are known generically in the United States as spandex (elastane in Europe). These were developed by Bayer under the tradename Dorlastan and by Du Pont as Lycra. These materials are highly elastic and can withstand elongation of several hundred percent before breaking. They are exttuded into filaments for textiles and are commonly used in elastic fabrics, especially sportswear. 

Figure 6. Carbon footprint of cotton textiles with yarn thickness comprised between 70 and 300 dtex (left) and synthetic textiles - acryl, nylon, PET, elastane-, with yarn thickness of 70 dtex (right) [59]...

The main use of fluorescent dyes is in the coloration of synthetic fibres, especially polyester, polyamide and acrylics in conjunction with elastane fibres, for fashion, leisure and especially sportswear uses. The fluorescent textiles offer not only high design options but also a large degree of safety in use, for instance increasing the visibility of cyclists and runners in busy urban areas. 

Synthetic Fibers Nylon, Polyesters, Acrylics, Elastane.161... 

Wool polyester mixtures are common for suits and better-quality trousers. Common mixtures are 54% polyester, 44% wool, although the better-quality fabrics have a higher wool content. One hundred percent wool is rare and subject to wear. Cheaper, crease-free trousers are 100% polyester, whereas cotton/polyester mixtures are common for hard wearing. Noncreasing fabric such as uniform or overalls are high polyester/cottons (e.g., 65%/35%). Jeans and casual trousers are often 100% cotton. Stretch fabrics usually consist of mixtures including polyester or Elastane. (e.g., 64% polyester, 34% Viscose, 2% Elastane 95% cotton, 5% Elastane). 

The bulk of men s underwear currently for sale is either 100% cotton or polyester-cotton (typically 65%/35%), although there are some stretch fabrics (e.g., 95% cotton, 5% Elastane). Stretch components may be confined to the waistband, or in some garments the base fabric also has stretch characteristics. 

We all use spandex, that extremely stretchable fiber known as elastane in Europe or called Lycra if manufactured by DuPont It provides the "stretch" in panty hose and other undergarments, swimsuits, jeans, cycling shorts, tights, and many other articles of clothing. 

To make a polymer it is necessary to react aryl diisocyanates with diols. Some important polymers -of the type, called elastanes, are made by using long-chain aliphatic diols from partly polymerized epoxides, rather like those discussed in the last section, and reacting them with diaryl diisocyanates to give a pre-polymer . 

One important elastane polymer that can be made by polymerization in a Ziegler-Natta fashion is rubber. Natural rubber is a polymeric terpene (Chapter 51) made from mevalonic acid and has a branched structure with regular trisubstituted alkenes, which are all in the Z-configuration. 

We will choose the example of elastane films for food wrapping— ClingFilm . These can be made from poly(vinylidene dichloride) (this is poly(l,l-dichloroethene)) into which a small amount of vinyl chloride is co-polymerized. The method is radical polymerization and the initiator usually a peroxide in aqueous suspension. 

Elastane. The DuPont Company commercialized the first manufactured elastic fiber, Lycra, in 1958. Originally categorized as a span-dex fiber, the name elastane has become more common around the world. This specialty fiber is described as a segmented polyurethane that contains hard and soft segments their ratio determines the amount of stretch built into the fiber. Elastane fibers are formed by dry-spinning or solvent-spinning. The continuous filaments can be coalesced multifilaments or monofilaments, depending on the manufacturer. 

Modified polyurethanes as shown in Fig. 4.6 are used for valuable hand variations and as additives for cellulose crosslinkers. Their flexible and elastic films on the fibre surface improve elastic resilience, which is, for example, important for pile fabrics. The principle of their elasticity is, as in elastan fibres, the molecular combination of so-called weak and hard segments. The large weak... 

Includes aramid, elastane, polyethylene, poly(vinyl alcohol), poly(vinyl chloride), and poly (vinylidene chloride). 

Polyurethane fibers (elastanes) can be made via either of the following two ways. In the first technique, the PU is first synthesized using the prepolymer method, and then the PU is spun from solution (approximately 30% PU) to form a filament or yarn. The yarn can either be collected as one long strand or be cut as it is collected. The second method, called reactive spinning, involves synthesizing the polyurethane and forming the filament all at the same time using a reactive bath to spin the fibers. ... 

Polyurethane fibers are another niche application. These elastanes, the basis of Lycra , have nearly taken over the textile industry, displacing rubber threads (elastodienes) in the process. The high popularity of PU fibers is attributable to the good tensile strength and elasticity of highly segmented polyurethanes. In addition, elastanes can be processed in a variety of sizes, either as continuous filaments (yarns) or as shorter fibers. Rubber threads, on the other hand, are available solely as monofilaments. ... 

Elastic fibres can be easily recognized by their great extensibility and elasticity as well as their longitudinal microscopic view (often quasi-monofil from coalesced single fibrils). As opposed to rare rubber threads, elastane fibres based on polyurethane dissolve in boiling dimethylformamide and swell markedly in 85% formic acid. 

The number and association of the primary filaments to multifil yams, the kind of thermal after-treatment (hot air, hot water) as well as the kind and amount of spinning oils varies between the many commercial varieties of elastane. Additional variety arises from further processing in the bare or covered form (elastic co-twisted, covered, core-spun or co-tangled threads). This variety can lead to mistaken identity and thus cause faults if the specific properties of each type are not given sufficient attention during processing. 

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