Textured yams

The air jet textured yam process is based on overfeeding a yam into a turbulent air jet so that the excess length forms into loops that are trapped in the yam stmcture. The air flow is unheated, turbulent, and asymmetrically impinges the yam. The process includes a heat stabilization zone. Key process variables include texturing speed, air pressure, percentage overfeed, filament linear density, air flow, spin finish, and fiber modulus (100). The loops create visual and tactile aesthetics similar to false twist textured and staple spun yams. 

Commercial textured yams cover a range of yam sizes and end uses. The 1.7—3.3-tex (15—30 denier) yams for hosiery are false-twist-textured, as is the 4.4—22.2-tex (40—200 denier) yams for apparel. The 56—333-tex (500—3000 denier) yams for carpets, upholstery, and soft-sided luggage are air- and fluid-jet-textured. 

Fundamentally, the manufacture of textured yarns is closely related to the heat setting of fabrics, which must be composed of thermoplastic fibers such as nylon or polyester, the difference being that the individual filaments or bundle of filaments in textured yams are distorted from an essentially straight rodlike form and then heat-set. In some instances, the fibers are distorted in a more or less random way at other times, a regular pattern is introduced. 

Textured yams and fibers, cellulosic made in chemical plants... 

Fig. 9. Dyeing of texturized yams of standard and modified polyesters with disperse dyes and carriers or at increasing temperature and pressure (HT process) ...

Bicomponent stretch fiber such as T400 also can be used in the classification of stretch and recovery properties, which positions it between elastane and standard mechanically textured yams. Self-crimp fibers behave like natural wool with a textured appearance. The crimps are from a composite of two parallel attached fibers with differing shrinkage or expansion properties. Usually, the crimp is generated by either false-twist or air-texturing on the fiber via mechanical deformation of the fiber as a 2D zig-zag crimp. A combination of various polyester materials can be used, for example, PET (polyethylene terephthalate), PTT, and PBT. 

Common varieties of elastomeric yams in sportswear include covered and core elastomeric yam for high stretch requirements and textured yam for low to medium elasticity applications. The processing technology for making elastomeric yams is mainly based on conventional methods such as core spinning, cover twisting, and air texturing. 

Textured yams give low to medium elongation and elastic recovery in sportswear. The current methods commonly used for sportswear yam production include false-twist, air jet, and BCF. 

Fignre 3 Stress train curves of texturing yams. 

New elastic fibers like comfort Lycra, XLA, polyester-based bicomponent fiber, and shape memory fibers provide a fit that is more relaxed than traditional spandex (Figure 3.10). Wearers feel less compressive force fighting against their movements in garments made of these fibers and blends than when wearing the same garment made with lower stretch textured yams and common spandex. 

Mukhopadhyay, A., Nayak, R.K., Kothari, V.K., 2004a. Extension and recovery characteristics of air-jet textured yam woven fabrics. Indian J. Fibre Text. Res. 29 (3), 62-68. 

Carpet is a complex, multicomponent system. The tufted carpet, the most common type (90%) as shown in Figure 16.1, typically consists of two layers of backing (mostly polypropylene fabrics), joined by CaCOs-filled styrene-butadiene latex mbber (SBR), and face fibers (majority being nylon 6 and nylon 6,6 textured yams) tufted into the primary backing. The SBR adhesive is a thermoset material, which cannot be remelted or reshaped. The waste containing the SBR (postconsumer and some industrial waste) has not found suitable uses, and it forms the major part of the carpet waste going into the landfills. Figure 16.2 shows the typical masses for the various components [13]. 

The threads used to lead to the velour stmcture in a fabric are texturized, usually by the false-twist method, and heat set so that they are pre-shrunk. These threads are also fed at a higher rate and lower tension than are the threads that form the rest of the fabric. The latter are plain, that is, untexturized, and not heat set. The warp comprises both types of yarn, and the fill may be of the unshrunk, untexturized, yam alone or may be used in combination with pre-shrunk, texturized yam, the two types twisted together (in the fill only) prior to weaving. When the tubular fabric is heat set to develop corrugations, only the unshrunk threads will shrink, not the pre-shmnk texturized yarns. This will cause the latter to form projected loops. 

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