عنوان مقاله [English]
نویسنده [English]چکیده [English]
The quality of superfine yarns, produced on a ring spinning machine, was investigated using a single filament as their core and its effect on the final properties of the produced core spun yarn was examined. For this purpose, a fine polyester monofilament was fed into the front roller of the draft zone in a ring spinning frame to be wrapped up by staple fibers of the cotton roving. Cotton roving with linear density of 1 Ne and polyester monofilament with linear density of 20 denier was used for the sheath and core section, respectively. For comparison, coreless (normal) yarns were produced in three and yarns with core were produced in eight drawing ratios. Three cotton rovings were drawn up to 30, 40 and 50 times on a three-roller ring drawing system, whilst the eight-core yarn samples were drawn by 30, 40, 50, 60, 70, 80, 90 and 100 times drawing ratios. Tensile strength, elongation, evenness and hairiness of normal and core spun yarns were measured and compared. According to the results, fine core spun yarns up to 72 English counts can be produced even with not very fine and uncombed cotton roving. Producing such fine yarns is not possible without core filaments and adopting special preparation techniques such as combing a high quality and very long cotton fibers. The presence of a filament core has improved elongation, unevenness and hairiness whilst it has not necessarily altered the core spun yarns tensile strength up to a certain limit.