The Hong Kong Research Institute of Textiles and Apparel (HKRITA) has developed a sustainable system to separate, categorise and recycle post-consumer leather products into useful raw materials for the manufacture of new products.
The context: Chrome tanning is a key process in leather production. However, this process generates harmful chemical residuals such as chromium VI converted from free chrome.
- These undesirable by-products can damage the environment and the health of living beings.
- Besides, conventional leather recycling uses synthetic materials such as PU and PVC to bind shattered leather waste together to form regenerated composite materials. These materials are neither biodegradable nor recyclable.
The recycling: The recycling is carried out in two steps which together providing a novel bio-based approach to obtaining sheets of regenerated leather.
- Shred a complete post-consumer leather product into pieces until leather fibres of high purity are obtained; then remove free chromium by transforming it into a soluble salt or complex compound.
- React the separated leather fibres with bio-based binders such as sugar or protein under mild conditions; collagen fibres become interconnected and form a new leather.
The chromium aspect: The reaction process retains the chromium as chromium III, thereby minimising its conversion to chromium VI.
- The regenerated leather has sufficient mechanical properties to allow it to be used in the manufacture of new leather products.
- It is water-resistant and biodegradable.
- The bio-based binders used in the process are also biodegradable and recyclable.
- The regenerated leather can be used to manufacture new products, creating a ‘virtuous circle’ for the recycling of post-consumer leather products.
Awarded project: The novel regenerated leather production technology has won two international awards this year.
- It was named an “Honourable Mention” in the Experimental Category of the May 2022 World Changing Ideas Awards conferred by Fast Company, an internationally recognised business media.
- The project also won a gold medal in the Special Edition 2022 Inventions Geneva Evaluation Days in March.
