Enabling Sustainability Through Ecodesign and Recyclability in the Textile Industry: Understanding Material Compositions of Denim

Abstract

Transitioning the textile industry towards sustainability requires circular strategies like ecodesign and design for recycling, to reduce virgin resource usage and textile waste. However, to ensure functionality, affordability, and individual styles, garments are composed of a variety of different materials, from fiber blends to haberdashery and décor items, making the composition of post-consumer textile waste difficult to predict and recycle. This material complexity contributes to the global fiber-to-fiber recycling rate remaining below 1 %.

This study examines the fiber composition of the product group denim trousers comparing fashion brands, jeans specialists and post-consumer products. While about 40 % of analyzed jeans are made solely of cotton and are generally a high-cellulose waste stream, many contain multiple fibers and highly variable elastic fiber contents, often unrelated to functional performance. Such blends significantly increase the technical difficulty and cost of recycling. Notably, fashion brands appear to use more pure cotton fabrics than jeans specialists, however offer also more loose fitting styles. These findings provide a basis and highlight the need for clear ecodesign guidelines and a strong extended producer responsibility to support a transition toward a circular textile economy. Accordingly, the study provides an example how the materiality and construction of products require re-consideration to move towards more sustainable product design.