Cotton is a natural fiber. It is one of the most easily dyeable fibers. Normally reactive dye is used for dyeing cotton fiber. Cotton can be died also with vat dye, direct dye, sulfur dye, mordant dye, etc. Flowchart of the flow chart of 100% cotton fabric dyeing is given below.
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Recipe making
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Select dyes
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Dyeing
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Hot wash
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Neutralization
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Soaping
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Cold wash
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Drying
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Match with standard sample
(If Yes)
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Bulk production
Basic Theory of Garment Dyeing:
- Hot brand reactive dyes
- Cold brand reactive dyes
1. Basic principle of garments dyeing with hot brand reactive dyes:
Cotton garments may be dyed with hot brand reactive dyes as per the following line diagram of the basic dyeing principle. At first load hot water in the dye bath and add salt, lubricant, sequestering agent, and maintain liquor pH at 7. Then load garments in the dye bath and start the machine running. Raise the liquor temperature of the dye bath to 80 degrees Celsius within 30 minutes. After 5 minutes at 800C, add dye solution in the dye bath within 15 minutes time. Continue dyeing for 30 minutes after dye addition in the liquor. Then add alkali to the dye liquor slowly within 15 minutes. After alkali addition, continue the dyeing process for 30 to 60 minutes. At the end reduce the liquor temperature to 70 0C and then drop the liquor.
2. Basic principle of garments dyeing with cold brand reactive dyes:
Load the garments with the required quantity of water and the garments to be dyed. Start the machine running and add salt to the dye bath. Continue processing for 10 to 15 minutes. Then add dye solution in the liquor through the chemical dosing door slowly within 20 minutes. Continue dyeing without temperature for the next 60 to 90 minutes. Then add sodium carbonate to the dye liquor and continue treatment for 30 to 45 minutes.
After color shade matching, drop the dye liquor and use cold water wash to the dyed garments to remove unfixed dyes from the garment fabric surface. Drop the liquor and use a light detergent wash onto the dyed garments to clean the garments. Drop the liquor and again use cold water wash to the dyed garments. After cleaning, unload the garments from the dyeing machine and dry the garments after hydro extraction.
Author of this Article: Rana Sohel Executive Engineer Sunman Textile Mills Ltd. Chittagong Cell: +8801912-420118 Email: rsohel07tex@gmail.com