Fully oriented yarn

Fully developed flow, 11 749-750 Fully integrated pilot plants, 19 458 Fully oriented yarn (FOY), 20 15 Fully processed foods, packaging,... 

Polypropylene filaments, fibres, fabrics, partially and fully oriented yarns perform well in cordage, netting, woven bags. .. 

These FOY (Fully Oriented Yarn) products therefore eliminated tire need for separate spinning and drawing stages, altliough not for all uses. In particular, the highest tenacity and modulus are best approached by a LOY plus high draw ratio route. 

FIGURE 2.21 One-step stack draw process. (From Tam, T.Y. and Lin, C.Y., A unique one-step process of achieving fully oriented yarn properties with <1500m/mintake-up speed. Fiber Society Spring Conference, Princeton, New Jersey, June 1996. With permission.)... 

Partly oriented yarn (POY) is a large product spun at about 3500 m min with a round cross-section, and draw-textured (DR 1.8, at about 1000 m min ) in a separate step. Fully oriented yarn (FOY) can be spun at >6000 m min or drawn in the spin-line (hot-tube spinning, HTS), or spin-drawn. Typical yarn titers are 30, 50, 76, 110, and 176 dtex, and the filament titers 2-3 dtex, although there is a trend toward values of 1 dtex or lower. 

Table 5.17). For example, PET needs to be spun at speeds of 5000 m/min and above in order to exhibit significant crystallinity (see Fig. 5.23). As mentioned at the beginning of this chapter, the lack of crystallinity during the conventional low-speed spinning process forced the industry to use an additional step (drawing) immediately after the spinning process (two-step process, TSP). In this way, the PET fibers exhibit a high degree of orientation, and they wq fully oriented yarns (FOY).

As a measure of the level of the amorphous orientation, the factor based on sonic measurements, Fas, has been chosen. This value can theoretically vary from 0 for fully unoriented to I for perfectly oriented situations. In practice, this orientation parameter varied from 0.69 to 0.83 in this series of drawn yarns. Experimentally, Fas is determined from the formula... 

Most bulked continuous filament fibers are produced for apparel applications and are processed using a two-step method. In the first step the fibers are spun as straight flat yarns at speeds between 3500 and 5500 m per min, which results in a fiber that is only partially oriented but fully crystallized. 

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