Gentle, Cost-Efficient Decolouring of Reactive-Dyed Cotton

Objective

CHT Group is seeking to develop or identify a gentle, cost-efficient decolouring agent — the active medium (chemical, enzyme, biocatalyst or formulation) — that removes reactive dyes from cotton without damaging the fibre. CHT Group would like to add the product or formulations derived from it to its portfolio and offer them to its customers for the decolorization of cotton for the corresponding end uses.

PoC Goal:

Within the Venture Client framework, validate a working process on standard cotton samples that:

• Demonstrably removes or strips off reactive dyes from cotton
• Preserves the mechanical strength of the fibre (measurable against a known-baseline standard textile)
• Runs within standard dyehouse process conditions (temperature, cycle time and existing equipment)
• Operates at a process cost in the range of today's standard auxiliaries

The PoC is expected to focus on reactive-dyed cotton and to run on standard samples provided by CHT (or on a product/auxiliary provided by the solution provider and tested by CHT). CHT can objectively measure fibre preservation against the state-of-the-art benchmark using established textile test methods — average degree of polymerisation of the cellulose, tensile (tear) strength and bursting-strength tests — alongside decolouration.

Long-Term Goal:

Bring a jointly developed, certifiable process to market as a sustainable specialty product for both textile finishing and textile recycling, with the potential to reach volumes of hundreds of tons per year and to give CHT a competitive advantage.

Solution Requirements

Functional

• Remove reactive dyes from 100% cotton, or reliably render them washable out after treatment
• Preserve the mechanical strength / integrity of the cotton fibre (no significant loss of tensile strength)
• Work in a water-based (aqueous) process with standard textile finishing equipment (e.g. jet-machines) — the equipment dyehouses already use. The product itself can be liquid or powder, as long as it works in the aqueous bath.
• Keep cycle time within an industrially reasonable window (not multi-hour treatments that block machines)

Technical & Security

• Mild, fibre-friendly chemistry — technology-open; enzymatic is one possible idea but not preferred or required (reductive, mild-oxidative, biotechnological or combined approaches are equally welcome if they meet the requirements)
• Less hazardous chemicals and free of CMR and SVHC labeled chemicals
• Work at moderate temperatures — low temperature (e.g. 30–40°C) is an advantage as it saves heating energy; enzymes typically do not tolerate high heat
• Use readily available, cost-efficient catalysts/actives rather than rare or precious materials
• Be compatible with, or improve on, current process conditions used in dyehouses

Operational readiness

• Testable as a functional PoC on standard cotton samples within a reasonable timeframe
• Provider able to work hands-on with CHT to demonstrate how they approach the problem (a finished, off-the-shelf solution is not required at application)

Nice-to-haves

• Certifiability / compatibility with textile sustainability standards (ZDHC, bluesign, GOTS, REACH compliance)
• Low or no additional auxiliaries required alongside the core product
• Highly concentrated product that can be diluted for use (lower process cost per litre)
• Understanding of the textile world and dyehouse practice on the provider's side

Not in Scope

• Indigo / denim (different dye chemistry — explicitly out of scope for now)
• Vat dyes and the broader range of cotton dye systems (noted for specific applications such as medical/military workwear, but not the current focus — priority is reactive dyes)
• The downstream use of the recovered material (respinning, recycling process itself) — not part of the decolouring process to be developed
• Turnkey end-to-end processes, recycling plants or full services
• Pure dyeing / recolouring solutions — the need is dye removal (decolouring), not colouring