Construction of twin staple-core spun yarn with two points of yarn formation in one twisting process

In order to diversify the structure of spun yarn as textile material and to develop novel composite spun yarn with good functionality, we investigated how to construct single yarn with a twin staple-core and sheath structure and/or adopt the production method of triplet spun yarn using an experimental ring spinning frame. Fundamentally, the unique spinning conditions were not only the arrangement and the distances of three rovings and the twist level of yarn, but also the types of staple fibers. The following results were obtained: (1) by adopting the production method of triplet spun yarn with three rovings under the spinning condition with two differing roving distances, the yarn combining side-by-side and sheath-core structures could be constructed by two points of yarn formation and one twisting process without the device for controlling of spinning tension; (2) in the spinning method of twin staple-core spun yarn, it was necessary to control the difference between spinning tensions of the sheath layer and the twin staple-core layer with side-by-side structure under the spinning condition with the lower twist level of yarn and the greater difference between two roving distances; (3) for combining the twin staple-core and the sheath layers, it was important not only to control the greater length of drafted fiber strands for the sheath layer, but also to choose the cut length of the sheath and the core fibers.