Reactive Dye Auxiliaries

Reactive dye auxiliaries are the non-dye chemicals that drive cellulosicnreactive dyeing: electrolytes that push dye onto the fiber, alkalis that fix it, andnprocess aids that keep the bath clean and even. They carry no colornthemselves. Get the electrolyte and alkali dosing right and shade depth, levelness,nand wash fastness follow.

Electrolyte forces dye exhaustion onto the fiber. Two salts dominate: sodiumnsulfate (Glauber's salt) and sodium chloride (common salt). Common salt is cheapernper tonne, but its chloride attacks stainless-steel dyeing machinery over time;nsodium sulfate costs more and is gentler on equipment. Choose by total cost, countingnmachine corrosion, not the salt invoice alone. Typical dosing runs tens of grams pernliter, scaled to shade depth.

Alkali triggers the dye-fiber bond. Soda ash (sodium carbonate) is the standardnfixation alkali; sodium bicarbonate gives slower, more controlled fixation forndifficult shades. Hard-water metal ions cause shade variation and dye aggregation, sona chelant such as EDTA sequesters calcium, magnesium, and iron in the bath. Urea aidsndye solubility and fiber swelling, and acetic acid neutralizes the bath beforenunloading. Soften the water first; it is the cheapest fix for off-shade lots.

• Exhaust and pad-batch reactive dyeing of cotton, viscose, and other cellulosics
• Electrolyte dosing for controlled dye exhaustion and shade depth
• Alkali fixation programs (soda ash / bicarbonate) for level, wash-fast shades
• Bath sequestration of hardness metals to prevent shade variation
• Post-dye neutralization and pH control before soaping and rinse

• Sodium sulfate u2014 PubChem
• Sodium chloride u2014 PubChem
• Sodium carbonate (soda ash) u2014 PubChem
• Sodium bicarbonate u2014 PubChem
• EDTA u2014 PubChem
• Urea u2014 PubChem
• Acetic acid u2014 PubChem