Garments are often made from a blend of different fibres to improve fit, style, comfort and longevity. There were no commercially viable separation and recycling technologies available for the most popular combinations such as cotton and polyester blends. HKRITA has developed a chemical hydrothermal treatment to selectively decompose cotton into cellulose powders, enabling the separation of the polyester fibres from the blends.
The whole process uses only heat, water and less than 5% of a biodegradable green chemical to achieve a recovery rate of over 98% for polyester fibres in 0.5-2 hours. A pre-industrial scale hydrothermal system is set up in a Tai Po factory to evaluate the parameters for scale-up, such as energy consumption and optimisation of operation.
The quality of the polyester fibres is retained, ready for spinning and manufacturing of new fabric. The cellulose powders, decomposed from the cotton, can be applied to functional products such as super-absorbency materials or regenerated fibre.More Projects