Recyclable, eco-friendly dyeing of silk/polyamide two-component fabric using sustainable Monascus pigments based on a nano suspension system.

Microbial dyes, one major kind of natural dyes, are gaining popularity due to their eco-friendliness and resilience to climate change. Silk is not only an important biological macromolecule but also an excellent textile material, and the two-component fabric blended from silk and polyamide has many advantages. This study explored using recyclable, eco-friendly Monascus pigments in a nano suspension system to dye the fabric. Nano-scale pigments avoided the need for organic solvents and ensured uniform dyeing. Monascus pigments formed a stable nano suspension in water, enabling a one-bath dyeing process, reducing time, costs, and sewage. The dye solution was reusable, maintaining beautiful color after four reuses. Optimal conditions for red and yellow Monascus pigments were identified, achieving high color depth, good rubbing and soap fastness, and UV resistance. The optimal dyeing conditions for red Monascus pigments were 80 °C for 50 min with a dosage of 25 % owf, achieving the highest color depth with level 4 rubbing fastness and soap fastness exceeding level 4. Similarly, for yellow Monascus pigments, the best results were obtained at 80 °C for 80 min with 27 % owf, also reaching level 4 in both rubbing and soap fastness tests.