Colour Chronicle - June 2013

TEXTILE
Summary of the key features of modern
ultra low liquor ratio machines
• The liquor ratio is reduced from 8:1 to 4:1
for cotton processing.
• Reduced fabric tension and friction for
better fabric running conditions in the
chamber (tangle free).
• Contact free dyeing (between the fabric and
bulk volume of the dye bath). Dyeing takes
place in the nozzle.
• Shorter processing time (e.g. faster loading/
unloading, heating/cooling, filling/
draining).
• Reduced energy, water and chemical
consumption.
• Novel, water saving rinsing systems e.g.
Then® direct rinsing ‘shower principle’.
• Low liquor ratio conditions even when the
machine is under-loaded.
• Improved microprocessor control.
Process and dyestuff requirements
When dyeing at low liquor ratio, the selection
of the reactive dyes is critical as they need to
fulfill the following high requirements:
Process requirements
• Only a low amount of liquor is available to
prepare the dyestuff solution (LR 1.5:1).
• Excellent shade transfer from lab (LR
8:1) to production (LR 4:1) and shade
reproducibility from bulk to bulk.
• Perfectly level dyeing with very good fabric
appearance must be achieved at LR 4:1.
• Rinsing and washing off at low liquor ratio.
All the key points at one glance
Drimaren® Electrolyte Diffusion Migration Substantivity Exhaustion Fixation
Stability
(80g/l Na 2
SO 4
) [%] [%] [%] [%]
G. Yellow HF-CD >35 g/l 7 5 59 88 82
Orange HF-2GL >35 g/l 5.5 4 61 96 91
Red HF-6BL >35 g/l 7 4-5 60 91 81
Red HF-3B >35 g/l 5.5 4-5 55 97 93
Blue HF-RL >35 g/l 5.5 4-5 68 93 83
Blue HF-2B >35 g/l 5.5 4-5 64 91 86
Dark Blue HF-CD >35 g/l 5.5 4 55 90 82
Navy HF-GN >35 g/l 7 4-5 60 92 88
Requirements of reactive dyes
• High solubility in presence of salt and alkali
(solution stability).
• Low influence of salt concentration and
liquor ratio on dye yield (high neutral
substantivity).
• Very good migration (levelling) properties,
on the fibre, during the neutral phase. High
reactivity and fixation in the alkaline phase.
• Very high fixation reactive dyes requiring
less salt. Very good diffusion and low
substantivity of the hydrolyzed dye.
Drimaren® HF reactive dyes meet the
needs of Ultra Short Liquor Ratio
dyeing:
• High solution stability (in the presence
of salt).
• High neutral substantivity.
• Very good migration.
• Very good diffusion.
• High reactivity and degree of fixation.
• Excellent wet fastness can be achieved by
rinsing at a temperature of only 60ºC.
• By adopting Clariant’s Drimaren® HF
range of poly-reactive dyes, on modern
ultra low liquor ratio, exhaust dyeing
machinery, vast savings in water, energy
and chemical consumption are possible,
reducing the environmental footprint of the
textile produced.
7 COLOUR CHRONICLE__JUNE 2013