Sustainable colouration concepts Part II. Waterless dyeing using supercritical carbon dioxide

This article series is about latest trends and future perspectives in colouration technologies. The second  part is about colouration using waterless dyeing concepts which is based on supercritical carbon dioxide, a technology invented in Germany 25 years ago.

Water scarcity in many parts of the world is according to consensus view of the experts one of the potentially big crisis issues for the future (read water crisis). The textile industry being a major polluter and consumer of fresh water has to address this issue urgently and needs to develop more sustainable production concepts.

In part I. of this article series I have reported about new colouration concepts without any dyes or water consumption based on the “Morpho effect” which is purely a physical effect. However it will take time and requires more fundamental research until this technology would be established, and I would consider it as a fashion niche rather than a technology for bulk manufacturing.

In future, there will be demand for novel coloration technologies, waterless dyeing and recycling dyeing methods. In particular, waterless dyeing concepts such as dyeing of polyester fibres from supercritical carbon dioxide (sc-CO2) are of major interest.

Supercritical fluids such as sc-CO₂ are already established in the extraction of natural ingredients for food, pharmaceuticals or cosmetics. Examples are aroma extraction, decaffeination, defatting, pesticide removal, phytoextraction, and sterilization (Evonik).