Aug 07, 2023

R&D 100 winner of the day: Green Machine — using hydrothermal technology to separate and recycle polyester and cotton blends

By Heather Hall | June 2, 2023

Cotton and polyester blended-fiber fabrics have been extensively used by clothing manufacturers, and these materials have made up a considerable number of garment wastes disposed of by consumers. Green Machine uses The Hong Kong Research Institute of Textiles and Apparel Limited (HKRITA)'s hydrothermal technology to separate PET-cotton blended textile fibers and decolor the PET fiber with crosslinked polystyrene beads and activated carbon particles for re-spinning into new yarn. The hydrothermal separation process is a highly efficient and green separation process with over 98% recovery of polyester, using 95% reusable water and less than 5% organic acid. Through PET decoloring, more than 95% of dispersed dye color removal can be achieved on recovered PET, improving the reusability and versatility of the recovered PET material. The cellulosic powders can be used as raw materials in regenerated cellulosic yarn and PFC-free water-repellent textile finishing. Meanwhile, the recycled cellulosic powder is produced into superabsorbent polymer for cotton plantations.

The Hong Kong Research Institute of Textiles and Apparel Limited (HKRITA)