Partially oriented yarn

Figure 13.6 (a) Elongation as a function of wind-up speed for partially oriented yarn, (b-d) Stress-strain curves of fibers of PET blends with 3% copolyester of 1,4-phenyleneterephthalate and p-oxybenzoate (CLOTH) and 3% copolymer of 6-oxy-2-naphthalene and p-oxybenzoate (CO), spun at 3500, 4000 and 4500 m/min (1) PET control (2) 3 % CLOTH (3) 3 % CO the loci of the theoretical extensions of the PET control are shown as dashed curves [17]. From Orientation suppression in fibers spun from melt blends, Brody, H., J. Appl. Polym. Sci., 31, 2753 (1986), copyright (1986 John Wiley Sons, Inc.). Reprinted by permission of John Wiley Sons, Inc. 

PTT polymer pellets must be dried to a moisture level of <30 ppm, preferably in a close-loop hot air dryer, to avoid hydrolytic degradation during melt processing. Drying is canied out widi 130°C hot air witli a dew point of <—40°C for at least 4h. Because of tire faster ciystallization rate, PTT pellets are already semicrystalline after pelletizing, and do not require pre-crystallization prior to drying as with PET. The dried polymer is extruded at 250-270 °C into bulk continuous filaments (BCFs), partially oriented yarn (POY), spin-draw yarn (SDY) and staple fiber. 

Brown and Chuah [84] and Oppermann et al. [36] studied tire spinning of partially oriented yarn (POY) as a function of take-up speed from 500 to 5000 m/min. Figures 11.18 and 11.19 show, respectively, development of tire tenacity and elongation as a function of spinning speed. Tenacity increases witli increasing... 

Partially oriented yarns (poly) n. Filament yarns in which the draw ratio is less than normal resulting in only partial longitudinal orientation of the polymer molecules. 

The dried polymer is extruded at 250-265° C into fibers using conventional processing machines for bulk continuous filaments (BCF), partially oriented yarn (POY), spin-draw yarn (SDY), and staple fiber. 

POY-DTY partially oriented yarn-drawn textured yarn... 

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