In this experiment, we use a 44.4 dtex/4f spandex filament as the core and cotton fibers as the sheath to spin 19.7 tex elastic core-spun yarn. In order to improve yarn performance, we examine the yams cross-sectional structure and investigate the effect of draw ratio and feed-in angle of the spandex on the yarns' structure and performance. The results show that a higher feed-in angle provides a better cover effect and a draw ratio of 3.5 yields better dynamic elastic recovery.

In this study, spandexes of three degrees of fineness are used as the core material with cotton fibers as the sheath to spin fine elastomeric yarns. We observe the cross sections of the core yarns and the migration of the spandex inside the core yarn concluding that producing a finer elastomeric yarn with a uniform structure is feasible. The results show that choosing the optimum spinning conditions gives a better cover effect to fine elastomeric yarn. In terms of elasticity, a 10 tex elastomeric yarn produced with a 2.2 tex/2f spandex core at a draw ratio of 4.0 and with a twist factor of 40 exhibits the best dynamic elastic recovery percentage.