In this study polyester staple fiber core/viscose sheath yarns were produced in order to understand the influence of spinning parameters on DREF-3 yarn unevenness, imperfection and hairiness properties. Yarns having 65 tex linear density, were produced with using three different core/sheath ratio level × three different spinning drum speed × three different air suction pressure at 4200 rpm constant opening roller speed and 100 m/min constant production speed. The unevenness, imperfection and hairiness properties of experimental yarns were tested with Uster Tester 3, at a speed of 200 m/min for 5 minute. Obtained results were evaluated with regression analysis using SPSS statistical pocket program at 0.05 significance level.
According to analysis results, the air suction pressure is a significant factor for yarn hairiness. The increase of air suction pressure decreases the slippage between spinning drum cylinders and fibers (2). For this reason, at higher air suction pressure, the sheath fibers wrap better around core and yarn hairiness decreases. The wrapper fibers cause hairiness, due to their buckling form in the yarn. With the increase of sheath ratio, the number of wrapper fibers increase thus yarn hairiness increases. At higher spinning drum speeds the fibers in the sheath are damaged and the number of hooks at the end of fiber increases (2). As a result of this, yarn hairiness increases. On the other hand, the core/sheath ratio, spinning drum speed and air suction pressure are not significant factors for unevenness, the number of thin places, thick places and neps properties of polyester staple fiber core/viscose sheath yarns.
