Segmented polyurethane fibers

Segmented polyurethane fibers (DIN) see also EA Polyurethane (DIN ISO lUPAC NS) see also PU... 

Meng Q, et al. Polycaprolactone-based shape memory segmented polyurethane fiber. J Appl Polym Sci 2007 106 2515-23. 

Meng Q.H., Hu J., Zhu Y, Lu J. and Liu Y. (2007), Polycaprolactone-based shape memory segmented polyurethane fiber. Journal of Applied Polymer Science, 106 pp. 2515-2523. 

DNS 1. Di(3,5,5-trimethylhexyl) sebacate (WTR) EA Segmented polyurethane fiber (Elasthan... 

Polyurea fiber DIN) see also PB Segmented polyurethane fiber DIN) see also EA... 

Other elastomeric-type fibers iaclude the biconstituents, which usually combine a polyamide or polyester with a segmented polyurethane-based fiber. These two constituents ate melt-extmded simultaneously through the same spinneret hole and may be arranged either side by side or ia an eccentric sheath—cote configuration. As these fibers ate drawn, a differential shrinkage of the two components develops to produce a hehcal fiber configuration with elastic properties. An appHed tensile force pulls out the helix and is resisted by the elastomeric component. Kanebo Ltd. has iatroduced a nylon—spandex sheath—cote biconstituent fiber for hosiery with the trade name Sidetia (6). 

More recentiy, melt-spun biconstituent sheath—core elastic fibers have been commercialized. They normally consist of a hard fiber sheath (polyamide or polyester) along with a segmented polyurethane core polymer (11,12). Kanebo Ltd. in Japan currentiy produces a biconstituent fiber for hosiery end uses called Sideria. 

In the second step, a papermaking method is also used for the fine fibers, less than 0.1 tex (1 den). This process is usually followed by a high pressure water jet process instead of the third step. In the fourth step, to obtain the required properties in specific appHcations, a polyurethane is selected out of the segmented polyurethanes, which comprises a polymer diol, a diisocyanate, and a chain extender (see Urethane polymers). A DMF—water bath for coagulation is also controlled to create the adequate pore stmcture in combination with fibers. 

Seed stage medium, 77 28 Seed trains, in fermentation, 7 7 42 Segmented-arc nozzle design, 76 8 Segmented elastomeric polyurethane fibers, 25 476-477... 

A manufactured fiber in which the liber-torming substance is a long-chain synthetic polymer comprised of at least 85% of a segmented polyurethane. A portion of the molecule may appear as ... 

Segmented elastomeric polyurethane fibers (Spandex fibers) based on MDI have also been developed. 

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. 

Not all copolymers which are produced by step-growth processes are random in nature. Block copolymers are also of major interest. An example of the synthesis of elastic polyurethane fibers was given in Section 1.5.4. Block and graft copolymers of polysiloxane-poly(alkylenc ethers) with segments like5-9 are used as surfactants in the production of polyurethane foams with uniform cell sizes. 

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. ... 

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