In this study; core PES filament/sheath polyester staple fiber and core PES filament/sheath viscose staple fiber DREF-3 core yarns’ strength properties which produced with using different spinning parameters, are investigated. In order to understand the effect of spinning parameters on DREF-3 core yarn strength properties, 65 tex yarn linear density PES/PES and PES/Viscose DREF-3 core yarns, are produced with using three different core/sheath ratio levels, four different spinning drum speeds, four different air suction pressures at 4200 turn/min. constant opening roller speed and 100 m/min. constant production speed. The strength properties of yarns are tested and obtained results are evaluated with regression analysis using SPSS statistical program at 0.05 significance level.
The effect of core/sheath ratio on yarn strength and yarn breaking elongation properties is significant. When using coarser filament in the core of the yarn, the filament breaking strength is rising and thus yarn strength increases. Due to the feeding system, sheath fibers are in buckling form, helically wound position in the yarn structure and this situation create more chance for yarns to have higher breaking elongation ratio. On the other hand, with the increase of filament ratio, sheath ratio decrease and core yarn elongation ratio decreases.
The increases of spinning drum speed damages the fibers in the sheath and increase the number of hooks in the end of fibers and as a result of this, core yarn strength decreases. However, the increase of spinning drum speed has not an important effect on core yarn breaking elongation ratio. With the increase of air suction pressure, in PES/Viscose yarns, sheath fibers are more tightly hold to each other and thus the contribution of sheath fibers, core yarn strength and breaking elongation ratio increase. On the other hand, air suction pressure doesn’t have an important effect on yarn strength in PES/PES yarns. The effect of air suction pressure changes according to the raw material type and physical properties of sheath material.
