Flow Chart of Cotton Bleaching Process

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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:

Flow Chart of Cotton Bleaching Process
Cotton Bleaching Process

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

Besides the above bleaching method, some fabrics are bleached by the older method. All the bleaching processes reduce the strength of the fiber. If durability is more important than appearance, the consumer should select grey goods rather than bleached materials. With continued laundering, grey goods will gradually whiten. The bleaching procedure is a vital pre-treatment and it should be done without any errors in order to gain the total absorbency and unique level of whiteness. The purpose of bleaching includes the elimination of a variety of natural, added, or acquired contaminations from the grey cloth as efficiently as possible, with less or no damage to the fiber and leaving the fabrics in a perfectly white state. The harm to the cloth refers to the decrease in the tensile strength of the fabric caused by lessening the degree of polymerization of the cellulose chains because of molecular chain breakdown. Bleaching can also be specified as a procedure of producing the fabric whiter, regardless of whether the purification is done for making of dyeing, printing, or in the procedure of goods to be finished as white.
Author of this Article:
Md. Abu Sayed 
Founder of Textile Apex 
Pabna Textile engineering college, Pabna, Bangladesh 
Email: [email protected] 
Cell : +8801745214773

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