Comparative study of fiber trapping by filaments in conventional and diagonal sirofil systems

Abstract

In this study, geometrical and theoretical analyses were conducted comparatively for fiber trappings by filaments in the left diagonal, conventional and right diagonal sirofil with right strand and left filament arrangement (denoted as LDS-RS-LF, CS-RS-LF and RDS-RS-LF, respectively)and left diagonal, conventional and right diagonal sirofil with right filament and left strand arrangement (LDS-RF-LS, CS-RF-LS and RDS-RF-LS, respectively). White filaments and blue rovings were used to produce conventional and diagonal sirofil yarns to validate the analysis. Online and offline fiber trapping capacity comparisons indicated that CS-RS-LF and CS-RF-LS had higher capacities of trapping fibers than LDS-RS-LF and RDS-RF-LS, respectively, and lower capacities than RDS-RS-LF and LDS-RF-LS, respectively. Yarn appearance and tensile properties results revealed that diagonal sirofils with improved fiber trappings increased yarn hairiness and tensile properties, while the ones with deteriorated fiber trappings decreased yarn hairiness and tensile properties. Sirofil yarn unevenness CVm decreased as the fiber trapping enhanced by RDS-RS-LF and LDS-RF-LS and increased as the fiber trapping weakened by LDS-RS -LF and RDS-RF-LS. This corresponded well to our theoretical hypotheses on fiber trappings by filaments in conventional and diagonal sirofil systems.

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

“…Similarly, the new concept yarn that was twisted with longer filaments (Figure 4) had a lower CVm value than the corefil spun yarn within an equal section. In addition, the filaments had no functions of trapping staple fibers during the corefil spinning according to a previous study; 29 decreased capacities of trapping staple fibers could lead to a decreased irregularity and sharply increased hairiness of corefil spun yarn. 29 Excessive hairiness would be entangled together on the corefil yarn surface to form neps.…”

“…In addition, the filaments had no functions of trapping staple fibers during the corefil spinning according to a previous study; 29 decreased capacities of trapping staple fibers could lead to a decreased irregularity and sharply increased hairiness of corefil spun yarn. 29 Excessive hairiness would be entangled together on the corefil yarn surface to form neps. 30 The increased corefil yarn imperfections, such as neps and hairiness (Table 2, hairiness H value) definitely deteriorated the corefil irregularities further.…”

“…Second, the configuration of filaments in the sirofil yarn structure showed an obvious wrapping curve (Figure 4(a)), incurring a large shear force to destroy filaments during yarn tensile drawing; in contrast, filaments were regarded as straight in the sirofil yarn inner structure (Figure 3(b)) and were difficult to break during tensile drawing of the yarn. 29 The new concept yarn had the combination of corefil and varied sirofil yarn structures. Therefore, the new concept yarn was weaker than the corefil yarn, but much stronger than the sirofil yarn (Table 3).…”

Study on properties of electromagnetic shielding yarns and fabrics

“…Or, one 15 um stainless steel filament was fed to the front roller from the left side of the blend strand and another one 15 um stainless steel filament was fed from the right side of the blend strand. Finally, under the twist, the polyester and cotton blend strand was twisted to the staple yarn firstly, and one 30 um stainless steel filament was wrapped on the staple yarn from the left side or from the right side, or two 15 um stainless steel filaments were wrapped on the staple yarn from the left side and the right side simultaneously, and corresponding sirofil wrapped yarn was produced (Xia et al , 2018).…”

Novel composite siro-spinning with forced migrations of filaments

“…8 However, this method is still not widely used to produce cotton composite yarns, owing to its complex management of four precisely located components. 9 To avoid complex management, cluster spinning has been developed; this involves electrostatically charging one multifilament cluster to produce outspreading monofilaments, which clasp staple fibers firmly in a spinning triangle zone. 10 However, cluster spinning is also not widely applied for yarn production, because the electrostatic charge risks setting the spinning mill on fire.…”