Cotton cone yarn with high colour depth, colour uniformity and colour fastness dyed by the environmentally friendly non‐aqueous medium of polydimethylsiloxane

Abstract To mitigate the pollution issue associated with traditional reactive dye‐based dyeing, non‐aqueous dyeing techniques have attracted extensive attention. In this investigation, cotton cone yarns were dyed using three primary reactive dyes within an environmentally non‐aqueous medium of polydimethylsiloxane (PDMS). Subsequently, aspects such as fixation, colour depth, colour uniformity and colour fastness were contrasted with those of traditional dyeing methods. The experimental results showed that the fixation of dyed cone yarns reached 90% in the PDMS dyebath, while the fixation of dyed cone yarns was only ca. 61% in the traditional dyebath. Furthermore, the K/S values of dyed cotton cone yarns in the PDMS dyebath were 19.7 (reactive red FC‐3B), 18.1 (reactive yellow FC‐3R) and 33.3 (reactive navy blue DE), respectively, 1.9, 2.1 and 1.5 times higher than those for the traditional dyebath. The colour uniformity of dyeing was also studied and the results showed that the ∆ E values of the inner, middle and outer layers of dyed cotton cone yarns were less than 0.5, showing excellent colour uniformity. Finally, fastness tests showed that the washing and rubbing fastness of dyed cotton cone yarns improved by half a grade or more in the PDMS dyebath compared with the traditional dyebath. After dyeing, PDMS was recycled and reused to dye. Importantly, the K/S values of dyed cotton cone yarns remained basically unchanged after five repeated cycles, and PDMS did not remain on the surface of the cotton cone yarns.