False-twist method

PTT POY yams were textured by the false-twist method at 140 to 160 °C. Crimp development was almost twice as high as PET, with crimp contraction reaching about 50 %. When PTT yams with a high level of crimp contraction are knitted into stretch fabrics, the amount of stretch achieved is equivalent to PET stretch fabrics incorporated with 6 to 8 % of Spandex [89], In addition to stretch, PTT fabrics tend to have softer hand and better drape than PET. Since they do not absorb moisture like nylon, PTT fabrics also have a desirable dry touch and comfort. 

False twisting See texturing, false, twist method. 

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. 

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. 

False-twist texturing depends on setting fibers in a kind geometry and then changing to another, which generates elongation that can be recovered by bulking. Another method is to set fibers in the required crimped form. This was the basis for stuffer-box and other methods. 

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