The following flowchart will be applicable for knit dyeing and especially for jet dyeing machines. Process Flow Chart of Scouring and Bleaching is as follows:
Process Flow Chart of Scouring and Bleaching:
Machine filling with water
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Chemical Dozing at 50 ºC
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Run time 10 min.
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H2O2 Dozing
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Heating at 60 0C
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NaOH dozing
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Heating at 110 ºC
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Run time 20 min.
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Cooling at 95 ºC
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Rinse at 80 ºC
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H2O2 – Killer Dozing
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Run time 10 min
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Run time 10min.
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Cooling for 55 ºC
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Acid wash 3 min → Drain
Scouring:
Scouring is the process of removing the impurities such as oil, fat, wax dust, and dirt from the textile material to make it hydrophilic. Bleaching is the chemical treatment for the removal of natural coloring matter from the fabric. The source of natural color is organic compounds with conjugated double bonds, by doing chemical bleaching the discoloration takes place by breaking chromophore. The material appears whiter after the bleaching.
Scouring is the process by which all-natural and adventitious impurities are removed to produce hydrophilic and clean textile material. It is one of the important processes of wet processing. It is done also for increasing absorbency of textile material.
Scouring objectives:
- In order to make the material extremely hydrophilic.
- To considerably absorb textile products without suffering chemical or physical harm.
- A neat material is generated by adding alkaline.
- For cotton removal of non-cellulosic material.
- In order to make the textile material prepared for subsequent bleaching.
Bleaching:
Bleaching is a chemical treatment employed for the removal of natural coloring matter from the substrate. The main purpose of bleaching is to ensure a pure and permanent basic white color fabric.
Objects Of Bleaching
There are many objects as follows –
- To remove the natural color.
- To-make the fabric permanent white and bright.
- Increase the absorbency power of the cloth.
- Increase dye affinity.
- Ensure level dyeing property.
- Make the fabric suitable for the next subsequent process.
Author of this Article: Rana Sohel Executive Engineer Sunman Textile Mills Ltd. Chittagong Cell: +8801912-420118 Email: rsohel07tex@gmail.com