Limits of Hollow Yarn in Friction Spinning

In hollow yarn spinning, the yarn is spun with a PVA filament in its core in the yarn-forming zone, which provides enough dynamic strength to the yarn during spinning. Therefore, the dynamic strength of the yarn is not so important a factor in spinning. In order to measure the spinning limit of a hollow yarn, we measure the strength and irregularity of the hollow yarns after extracting the PVA. The results show that the high PVA percentage hollow yarns do not show good tensile properties and irregularity. Both spinning and PVA extraction increase the irregularity of the cotton component in the yarns or hollow yarn products, while the effect of PVA extraction can be minimized by treating the yarns when they are formed into fabrics. We conclude that the PVA percentage should not exceed 40%. We also conclude that the middle count yarns (20 tex and thinner), which are not spinnable as conventional yams, can be spun on a friction spinning machine using the hollow yarn spinning technique.