New circular approaches for the development of sustainable textile coatings

 
The continuous move towards sustainability is motivating highly polluting industrial sectors to rethink their environmental impact and embrace the adoption of circularity strategies. The textile industry is one of the most resource-intensive sectors, contributing significantly to environmental pollution and waste generation. Traditional textile coatings, often based on petroleum-derived components, exacerbate these environmental challenges due to their non-renewable nature and difficulty to recycle. To address these concerns, the development of sustainable textile coatings implementing circular economy principles has become increasingly important. "From nature to people, in a circular and sustainable way" is the motto behind the be@t project - Bioeconomy at textiles, which aims to revolutionize the textile and clothing industry in Portugal by developing solutions that empower decarbonization, zero waste, ecodesign and traceability, along the entire textile value chain. Within the scope of be@t, one of the key research goals is the development of new sustainable textile coatings with relevant functionalities and improved environmental credentials, that are compatible with conventional and advanced textile finishing technologies. This study explores the use of spray coating as an environmentally friendly application method, and the use of plant-based waste as a source for biobased renewable raw materials containing bioactive compounds that provide the coatings with appealing functionalities. These materials not only reduce dependence on fossil fuels and promote resource-efficiency, but also improve end-of-life management through biodegradability, aligning with circular economy goals and contributing to a lower environmental impact. Spray coating is identified as a promising application method alternative to conventional ones such as padding or knife coating, due to its potential for minimizing material waste, reducing energy consumption, and enhancing the precision of coating deposition, leading to optimized use of raw materials. The developed coatings were formulated with micronized plant-derived waste or bioactive extracts, obtained through green(er) extraction processes, incorporated in water-based/solvent-free formulations which significantly reduce VOC emissions during the coating process, further enhancing the safety of the coatings. The application of these coatings was tested on various textile substrates, mainly focusing on natural fibers like cotton, wool, linen and hemp. The spray-coated textiles were assessed for key performance indicators, including light and washing fastness, and for functional properties relevant for the textile sector, such as antioxidant and anti-microbial activities, UV protection and hydrophobicity, and have demonstrated competitive performance when compared to conventional coatings. In conclusion, this study provides an overview of new circular approaches for sustainable textile coatings, highlighting the potential of spray coating as a sustainable application method and showcasing waste valorization as ways to revolutionize the textile industry by minimizing environmental impact and promoting resource efficiency. Future research will focus on optimizing these formulations for industrial-scale application and exploring new functional properties to meet evolving market needs. The authors acknowledge the financial support from the integrated project be@t - Textile Bioeconomy (TC-C12-i01, Sustainable Bioeconomy No. 02/C12- i01.01/2022), promoted by the Recovery and Resilience Plan (RRP), Next Generation EU, for the period 2021-2026.