Reactive dyeing
Also known as: Reactive dyeing, Cold pad batch
Dyeing process in which the dye forms a covalent bond with cellulose or wool fibres, producing extremely wash-fast results.
Description
Reactive dyeing was developed in 1954 by Rattee and Stephen at Imperial Chemical Industries and is today the dominant process for cotton, viscose and lyocell. Reactive dyes carry reactive anchor groups such as monochlorotriazine, dichlorotriazine or vinyl sulfone which form a covalent bond with the hydroxyl groups of cellulose under alkaline conditions (soda ash, caustic soda).
The process runs as exhaust dyeing in the jet (at 40-80 degrees Celsius), as cold pad batch (at room temperature with 12-24 hours dwell time) or as continuous pad-steam dyeing. After fixation, unreacted dye and hydrolysis products must be thoroughly rinsed out, which means high water consumption.
Reactive-dyed goods reach wash and rubbing fastness ratings of grade 4-5 according to ISO 105. The colour palette includes brilliant reds, yellows, blues and turquoises that other dye classes cannot achieve. Drawbacks are the high salt demand (up to 80 g/L sodium sulfate) and demanding wastewater treatment.
- Covalent bond to cellulose or wool
- Very good wash and rubbing fastness
- Brilliant shades, wide palette
- High water and salt consumption
Properties
| Chemistry | Covalent bond, alkaline fixation |
|---|---|
| Fibre suitability | Cotton, viscose, lyocell, wool |
| Fastness | Wash and rubbing fastness 4-5 |
| Environmental profile | High water and salt consumption |
| Appearance | Brilliant, deep or pastel shades |
Related product categories
Sources & references
1- Wikipedia: Reaktivfarbstoff Wikipedia — Freie Enzyklopädie https://de.wikipedia.org/wiki/Reaktivfarbstoff
