Topping in Dyeing:
Topping is the addition of color to the fabric after completing one dyeing process. Sometimes it is found that the dyed fabrics do not match with the standard or buyer-approved swatch then it needs to re-dyeing, this process is called topping. Topping is similar to the full dyeing process. Normally topping is done in the reactive dye for cotton dyeing. The flowchart of topping in cotton fabric dyeing is given below.
Flow Chart of Topping in Reactive Dyeing
Water fill at the required amount
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Fabric loaded and running for 10 min.
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Drain out
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Water was filled at the required amount
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Acetic acid was added for 5 min.
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The temperature increased at 60 ºC
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Run for 20 min.
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Rinsing for 10 min.
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Drain out
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Require amount of water-filled
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A wetting agent was added
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The temperature increased at 95 ºC
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Run for 30 min.
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Ringing for 20 min.
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Leveling agent added for 10 min.
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Salt dosing
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Color dosing for 30 min
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Run for 10 min
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Soda dosing
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Run for 1 hrs
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Temperature increase at 60 0C for 5 min
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Run for 10 min
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Shade check (OK)
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Rinsing for 20 min.
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Drain out
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Acetic acid was added for neutralization for 10 min
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Shade check (ok)
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Hot wash at 70 0C
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Rinsing for 10 min.
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The fixing agent was added for 10 min
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Rinsing for 10 min.
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Water was filled at the required amount
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PH check at 5.5
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Softener was added
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Final shade checks and run for 20 min
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Unload the dyed fabric
The reactive dye used in the exhaust dyeing method can make price effective with pigment topping but a maximum range up to 10% range in garment cotton knitted fabric. Otherwise, collar to body portion difference will be observed more but according to customer demand, it has to do cost-wise economical also. In a garment, more dye addition in reactive dyeing patchiness chances will be more whatever shade is coming the first time its tone can be adjusted with pigment topping within a short time.
Author of this Article: Rana Sohel Executive Engineer Sunman Textile Mills Ltd. Chittagong Cell: +8801912-420118 Email: rsohel07tex@gmail.com