Environment-Friendly High-Efficiency Continuous Pad Dyeing of Non-Shrinkable Wool Fabric by the Silicon Fixation Method without Auxiliary Chemicals

Conventional pad dyeing methods rely on auxiliary chemicals and consume high energy and a large amount of water to achieve continuous or semicontinuous pad dyeing. Here, a new continuous pad dyeing method was developed by using decamethylcyclopentasiloxane (D5) as the fixation medium; non-shrinkable wool fabric obtained an incredible fixation rate of up to 99% without auxiliary chemicals in the dyeing process. In this work, the optimal temperature and time of the D5-fixation process was 100 degrees C for 1 min. Compared with conventional dyed samples, non-shrinkable wool fabric with DS-fixation exhibited a better dye penetrability and higher color-fastness, color strength, and area shrink. Furthermore, the results of XRD, FT-IR spectroscopy, and SEM analyses indicated that D5 has no influence on the surface structure, micro-structures, and color properties of wool fabrics. Also, the wool fabrics exhibited good color properties with reused D5. This new continuous rapid pad dyeing method shows a lower commercial level with reduced consumption and nearly half of the wastewater compared with conventional pad dyeing methods, which has a considerable potential to promote the development of a sustainable continuous pad dyeing technology. D5-fixation has the potential to replace the cold pad-batch and steam fixation and would substantially reduce the environmental footprint and achieve real continuous pad dyeing in the conventional dyeing process.

Automated summary

A new continuous pad dyeing method using decamethylcyclopentasiloxane (D5) as the fixation medium was developed, achieving a remarkable fixation rate of up to 99% without auxiliary chemicals on non-shrinkable wool fabric. The D5-fixation process exhibited better dye penetrability and higher color-fastness, color strength, and area shrink compared to conventional dyed samples. Furthermore, D5 had no influence on the surface structure, micro-structures, and color properties of wool fabrics, and the wool fabrics showed good color properties with reused D5. This new method has the potential to promote the development of a sustainable continuous pad dyeing technology with reduced consumption and wastewater.