A novel concept to produce periodic varied structural composite yarn via cyclical changing of the spacing between filaments and the strand

Abstract

In this study, a novel concept has been developed as a cyclical spacing-change method to produce periodic varied structural composite yarn. Geometrical analysis indicated that the cyclical change of spacing between filaments and the strand altered the yarn formation zone shapes from corefil to sirofil, causing cyclic yarn structure variations from the hairy core–sheath (corefil section) to the smooth spiral filament wrapping (sirofil section). A mechanical analysis revealed the corefil section with more twists was thinner than the sirofil section with fewer twists. Specifically, the cross-sectional diameter performed gradual periodic changes from the thick sirofil section to the thin corefil section. Then, an eccentric godet wheel device was used to conduct confirmatory experiments. Besides validating the theoretical analysis, the experimental results also showed that the novel concept yarn had the minimum hairiness and medium irregularity and strength after comparisons with sirofil and corefil yarns.