Partially oriented yam POY

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 carried out with 130 °C hot air with a dew point of < -40 °C for at least 4 h. Because of the faster crystallization 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 yam (POY), spin-draw yam (SDY) and staple fiber. 

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

Figure 2.21 illustrates the one-step stack-draw process. The take-up speed of this one-step process is greater than 3000m/min. The product is known as the partially oriented yam (POY). The combination of drawing and textile finishing seems suited particularly for the production of POY at high spinning speeds. 

The partially oriented yam (POY) from the one-step stack-draw process, as illustrated in Figure 2.21, at a take-up speed faster than 3000 m/min is largely of the y-strueture. 

Keywords bulk continuous fibers (BCF), crystallinity, drawing, elasticity, elongation, fiber-forming polymer, fiber monofilament, low oriented yam (LOY), melt blown process, melting, monofilament, multifilament silk, orientation, partially oriented yam (POY), staple fibers, spinning, spunbonded fibers, stmcture, technical fiber, tenacity, textile fiber, texturing. 

In traditional textile spinning, some orientation of fibers is achieved by winding up the filaments at a rate of 3000-5000 m/min to produce the so-called partially oriented yams (POYs) (23). The POYs can then be mechanically drawn in a separate step to achieve maximum strength. In spunbonded production, filament... 

Fig. 10. Dependence of the production on spinning speed (89), where LOY is low orientation yam MOY, medium oriented yam POY, partially oriented...

Filament. Eully drawn flat yams and partially oriented (POY) continuous filament yams are available in yam sizes ranging from about 3.3—33.0 tex (30—300 den) with individual filament linear densities of about 0.055 to 0.55 tex per filament (0.5—5 dpf). The fully drawn hard yams are used directly in fabric manufacturing operations, whereas POY yams are primarily used as feedstock for draw texturing. In the draw texturing process, fibers are drawn and bulked by heat-setting twisted yam or by entangling filaments with an air jet. Both textured and hard yams are used in apparel, sleepwear, outerwear, sportswear, draperies and curtains, and automotive upholstery. 

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