Production and Recycling of Dope-Dyed Lyocell Fibers with Pigment Dyes

The annual consumption of textiles has risen rapidly in recent decades, significantly increasing the environmental impact of the textile industry and driving the need for more sustainable solutions. Man-made cellulosic fibers (MMCFs) have emerged as a promising alternative, as they are recyclable and can be made from renewable sources. This study investigates dope-dyeing (also known as spin-dyeing) of Lyocell-type fibers using pigment dyes. The addition of pigments did not affect the dissolution of the cellulose pulp or the rheological properties of the solution. The resulting fibers showed slightly lower elongation than pigment-free reference fibers but maintained competitive mechanical properties, with a high tenacity up to 50 cN/tex. Dope-dyed fabrics demonstrated excellent wash fastness and strong resistance to rubbing and abrasion. Additionally, chemical recycling of the dyed fibers was successful, showing only a slight decrease in mechanical properties and minimal color shade change. Overall, these findings suggest that incorporating pigments in the Ioncell process does not significantly impact fiber quality or performance, supporting the viability of dope-dying on a commercial scale.