Hollow Yarn in Friction Spinning

Abstract

"Hollow" yams have been created to improve cotton yam properties, to increase the entrapped air in the yam, and to gain a stronger yam for spinning and weaving processes. Hollow yams are spun by introducing PVA filaments into the yam-forming zone of an experimental friction spinning apparatus. A 61/18-denier (6.8 tex) PVA multifilament is used as the core and cotton fibers form the sheath. The water soluble PVA in the center is removed from the yam structure in boiling water with a good extraction of more than 95%. The effect of the PVA proportion on the mechanical properties of the hollow yam is examined, and its properties are compared with those of conventional cotton yams. The results show that the strength of the yam before boiling significantly increases as the PVA percentage increases, and it is more than that of an equivalent conventional cotton yarn. The strength of the hollow yam after PVA extraction does not change with the PVA content, and it is the same as that of the equivalent cotton yam. At a high filament percentage, the breaking elongation of the hollow yam is more than that of the cotton yarn.