[pic] | |Supercritical Fluid Dyeing SFD
In textile industry water is the usual medium for dyeing and cleaning. This is the reason why textile industry is one of the biggest consumer of water in all industries. Textile refining processes without using water have to be applied because costs of water and waste water are increasing more and more, the legislator fixes more rigorous limit values for the sewage load and also the water resources become more and more limited in several areas.
In cooperation with the DTNW (German textile research centre Northwest) Uhde has developed a textiles-refining process which is uncoupled completely from the water cycle. Therefore the new, ecologically sensible ways which are enough, moreover, also for the highest quality requirements are opened to the dyeing by textiles.
This innovative and ecologically friendly process uses supercritical CO2 instead of water. Supercritical CO2 distinguishes itself by his good solvent characteristics for dispersion dies (hydrophobic substances in general) and his low viscosity. The CO2 loaded with the colouring can penetrate therefore deeply into the pore system and capillary system of the textile fibre and causes thus an intensive colouring of hydrophobic synthesis fibres like polyester, Elastan and nylon. The results of numerous dyeing with supercritical CO2 in Uhde lab and pilot plants speak for the high potential of this application. Besides, yarn and fabrics with the highest colour fastnesses could be dyed in different nuances. Thus the additional colouring of pre-manufactured clothes (e.g., underwear, functional clothes etc.) with this process also is possible
This relatively new and innovative process offers unbeatable advantages compared to conventional dyeing.
• Qualitatively equivalent, partially better dyeing result • No damage of the fibre
• Significantly shortened process and dyeing times
• Low dye and chemicals consumption...
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