In fabric dyeing with reactive dyes, everyone faces some basic dyeing problems. Seeing those for the freshers youngsters here are some basic problems with the reasons of problems.
1- Shade variation batch to batch
- Process parameters such as water hardness, M:L, time, temperature, recipe, reproducibility of dyes, dye lot, fabric structure, GSM, fibre lot, yarn count etc. should be same as much as possible for minimising batch to batch shade variation problem.
2- Roll to roll shade variation and patchy
- Roll to roll shade variation produces a variety of shade within a batch
- Avoid fabric roll produced from different fibre lot, yarn count, GSM, structure and even sometime for different machines
- Avoid mixing of different types of fabrics
- Patchy is the real uneven dyeing
- Avoid uneven absorbency, electrolytes (salt) alkaline pH, uneven and sudden alkali dosing, wrong dye combinations, improper mixing of dyes, improper neutralization after scouring-bleaching and dyeing, fabric entanglement during process etc.
3- Colour spot and white specks
- Avoid improper colour mixing
- Avoid water hardness and presence of heavy metal sulphate, sulphides, sulphites and alkali especially caustic soda
- Water treatment plant (WTP), sequestering agent and proper mixing of dyes are fundamental solution of colour spot
- White specks are mainly yarn problem i.e. dead or immature fibres
- Moreover contamination in water, improper dissolve of alkali and presence of silica based chemical before dyeing also arise white spots
4- Fastness problems
- Fastness problems are the result of improper washing off, presence of unfix dyes, hydrolysis of dyes, dyeing with excessive dyes, poor fastness properties of dyes, improper use of fixer and softener.
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