If the cloth is to be finished white or is to be given surface ornamentation, all-natural color must be removed by bleaching. This is also necessary if discoloration or stains have occurred during the previous manufacturing process. It can be done in the yarn stage as well as in the constructed fabric. The kind of chemicals to be used depends upon the kind of textile fiber of which the fabric is composed. When the cloth has been bleached for finishing, it is called bleached goods. Flow chart of cotton bleaching process is as follows:
In the case of cotton goods, 85% of these fabrics are bleached by continuous peroxide methods. In this system, bleaching is done as follows –
Bleaching Flowchart of Cotton Fabric:
Singed goods are put through a rapid de-size steamer
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Washing
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Impregnation is done with 3% mild solution of caustic soda
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Pulled up into a J-box – Temperature is maintained at 1000 C
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Fabric is hauled out of the J-box
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Hot wash
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Impregnation is done with 2% solution of hydrogen peroxide
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Put in a second J-box for another hour
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Washing
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Fabric to the driers
Author of this Article: Md. Abu Sayed Founder of Textile Apex Pabna Textile engineering college, Pabna, Bangladesh Email: sayed1952@facebook.com Cell : +8801745214773