Denim Fabric Cotton Recovery by Mechanical Warp-Weft Separation

This project aims to develop a novel mechanical method to conduct separation of denim fabric and recover the dyed cotton warp and weft weaving components, usually made of synthetic fibres, in the denim structure. It tackles the difficulty of recycling denim due to the blending composition of yarns, which causes degradation of recycled yarn quality and lower recycling efficiency. Indigo-dyed yarn is recovered and preserved in good quality for further recycling.

Denim recycling and its technological challenges

Denim fabric is primarily made from cotton. However, the production of virgin cotton requires large agricultural and water resources, together with extensive consumption of fertiliser and pest control chemicals, while the denim dyeing process leads to water pollution and other environmental impacts. With the growing market of denim, there is the demand to reduce the environmental impact in the manufacturing of denim and technologies that can push forward the circular production of denim.

While denim fabric is primarily made from cotton, its weft yarn contains synthetic fibres such as polyester or spandex to provide stretch or improve durability. Such blended property adds difficulty in denim recycling using traditional mechanical approach.


The system can handle 6 common types of denim fabric such as left-hand twill and right-hand twill which account for over 90% of the denim fabric in the market.

Industry Benefit
  • Eco-friendly: separated dye cotton yarns are ready for reuse without the need to be re-dyed, saving operation cost on dyeing and wastewater treatment. The whole process is chemical-free and waterless.
  • High separation efficiency: achieving >90% of separation efficiency of warp yarn and weft yarn

Technological Breakthrough
  • A first-of-its-kind attempt to separate blended denim fabric using mechanical recycling approach (i.e. chemical-free and waterless). Dyed cotton warp yarns are separated and recovered without the need to be re-dyed.
  • Real-time AI vision detection of fabric weaving structure, warp yarn density, fabric orientation, and processability. Denim outside processing scope will be automatically returned to the feeding spot. 

49th International Exhibition of Inventions of Geneva (2024) - Bronze Medal
Project Name (ITF)
Denim Fabric Cotton Recovery by Mechanical Warp-Weft Separation
Project Number (ITF)