Polyurethanes fibers

The reaction imxture is then chain-extended with a diamine  

The prepolymers are spun into fibers and subsequently crosslinked, or crosslinked while they are being spun, to obtain resilient elastomeric fibers. 

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Butanediol [110-63-4] (BDO) goes primarily into tetrahydrofuran [109-99-9] (THE) for production of polytetramethylene ether glycol (PTMEG), used ia the manufacture of polyurethane fibers, eg, Du Font s Spandex. THE is also used as a solvent for PVC and ia the production of pharmaceuticals (qv). Lesser amounts of BDO are employed ia the production of polybutylene terephthalate resias and y-butyrolactone. 

Uses. Approximately 70% of the U.S. production is used to make poly(tetramethylene ether glycol) [25190-06-1] (PTMEG), also known as poly-THE, which is used in the production of urethane elastomers, polyurethane fibers (ether-based spandex), and copolyester—ether elastomers. PTMEG is also the fastest growing use (see PoLYETPiERS, TETRAHYDROFURAn). The remaining production is used as a solvent for the manufacture of poly(vinyl chloride) cements and coating, precision magnetic tape, a reaction solvent in the production of pharmaceuticals, and other miscellaneous uses. 

Uses of Methylamines. Dimethylamine is the most widely used of the three amines. Excess methanol and recycling monomethylamine increases the yield of dimethylamine. The main use of dimethylamine is the synthesis of dimethylformamide and dimethylacetamide, which are solvents for acrylic and polyurethane 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... 

Butanediol (BDO) goes primarily into tetrahydrofuran (THF) for production of polytetramethylene ether glycol (PTMEG), used in the manufacture of polyurethane fibers. 

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

Elastomeric polyurethane fibers [96, pp. 609-615], are contained in stretch articles and in knitted fashion materials. Light shades can be dyed tone-on-tone on polyamide-polyurethane mixtures with disperse dyes at 95-98°C and pH 6-7. However, the wetfastness of these dyeings on polyurethanes is lower than on polyamide. Because of the temperature sensitivity of polyurethane fibers, mixtures of elastomeric and polyester fibers must be dyed with small-molecular, rapidly diffusing disperse dyes in 30 min at 120 °C according to the HT process [148], Modified PES fibers that are dyeable at 100°C without a carrier are often used in mixtures with elastomeric fibers. In all dyeing processes for elastomeric fibers, dyeing equipment that permits low-strain guidance of the material and the lowest possible thermal stress are important. 

Spandex-type polyurethane fibers are chemically quite stable under normal washing and chlorine containing swimming pool water conditions. Special stabilizers are required for protection against ultraviolet radiation, suntan lotions, human perspiration, etc. 

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. 

Use Stabilizer in alkyd resins, maleic and other polyesters, polyurethanes, fibers, paint products, candles and perfumes, low-temperature lubricants and hydraulic fluids, manufacture of nylon 610. 

Initial work in the development of polyurethane technology, like nylon 6 development, was also stimulated by an interest in producing a nylon 6,6 fiber type by a polymer chemistry that did not infringe on the Du Pont patents. Polyurethane fiber from hexamethylene diisocyanate and 1,4-butanediol chemistry did have properties similar to nylon 6,6 fiber, but high-diisocyanate cost made this commercially unattractive (Eq. 21.19). 

Mixtures of isocyanates are commonly used for convenience in commercial production of the diisocyanate, since the pure toluene 2,4-diisocyanate is more expensive to produce. The resulting prepolymer is then mixed with either a glycol, such as 1,6-hexanediol, or a deactivated (sterically hindered) diamine plus pigment if required, and then promptly poured into a preheated mold of the desired shape. In about half an hour the mixture sets to a pliable shape with stiffness and elasticity controlled by the components and processing details used [29]. Similar procedures produce high-strength polyurethane fiber (e.g., Perlon U) or elastomeric fibers (e.g., Spandex and Lycra). 

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. ... 

Santeire JP et al (2005) Understanding the biodegradation of polyurethanes From classical implants to tissue engineering materials. Biomaterials 26(35) 7457-7470 Demir MM et al (2002) Electrospinning of polyurethane fibers. Polymer 43(11) 3303-3309... 

Butanediol (1,4 BDO) is an intermediate used to produce several important petrochemical and polymer derivatives. One of the most visible and widely used polymers is spandex fiber (polyurethane fiber) however, many other high performance polymers and solvents are made from 1,4 BDO. A complete description of supply, demand, and uses for its derivatives is included in Chapter 6. The manufacture of 1,4 BDO by each of several alternative commercial routes are major users of hydrogen for hydrogenation. 

The preparation, sjHnning, and drawing of copolymers PET—PEG were invest tigated more recently and it was ascertained that by incorporation under optimum conditions of about 5 mol % PEG (mol. wt. 4000) into PET, the polyglycol reacts with the terephthalic group and the copolymer obtained can be easily spun and drawn. However, fibers prepared in this way are far from having the elasticity of polyurethane fibers (e.g. Lycra) (Table 2). 

Shape memory polyurethane fiber Comfort elasticity Body temperature active... 

Figure 3.3 Development of shape memory polyurethane fibers.

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