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Stretch yarns are frequently continuous-filament synthetic yarns that are very tightly twisted, heat-set, and then untwisted, producing a spiral crimp giving a springy character. Although bulk is imparted in the process, a very high amount of twist is required to produce yarn that has not only bulk, but also stretch. Textured Yarns: 'Textured' is a general term for any continuous filament yarn whose smooth straight fibers have been displaced from their closely packed, parallel position by the introduction of some form of crimp, curl, loop or coil. Cord yarns are produced by twisting ply yarns together, with the final twist usually applied in the opposite direction of the ply twist. Cable cords may follow an SZS form, with S-twisted singles made into Z-twisted plies that are then combined with an S-twist, or may follow a ZSZ form. Ply, plied, or folded, yarns are composed of two or more single yarns twisted together. Two-ply yarn, for example, is composed of two single strands; three-ply yarn is composed of three single strands. single strands composed of fibres held together by at least a small amount of twist; or of filaments grouped together either with or without twist; or of narrow strips of material; or of single synthetic filaments extruded. |