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Bleaching process and recipe of rayon polyester polyamide

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Bleaching process and recipe of rayon polyester polyamide:

Bleaching process of rayon:

Rayon cloth, usually used for dyeing and printing, does not require any bleaching process. However, a scouring process is needed to eliminate various types of waste. Bleaching is only required if the fabric needs to be completely white.

Bleaching process and recipe of rayon polyester polyamide-Recipe:

Hydrogen peroxide (30%)⇒ 1.5 to 2% (percentage of fabric weight)

 Sodium Hydroxide ⇒ 0.8 to 1.2% (percentage of fabric weight)

Trisodium phosphate ⇒ 2 to 3% (percentage of fabric weight)

Sodium silicate ⇒ 1 to 1.5% (percentage of fabric weight)

Bleaching process and recipe of rayon polyester polyamide-Process:

The fabric is bleached for 1 hour to 2 hours or more (as required) at 80°C and washed with cold water.

Bleaching process of polyester:

Polyester is not usually bleached. Bleaching is required if it is blended with cotton. However, there is no need for bleaching for dyeing purposes. Bleaching is done to remove the natural color of cotton and get a pale white color.

Bleaching process and recipe of rayon polyester polyamide-Recipe:

Sodium chloride (80%)⇒ 1 to 2 g / liter

Sodium Hydrogen Phosphate ⇒0.5 g / liter

Sodium Nitrate ⇒1 to 2 g / liter

pH⇒ 3.8 to 4.2

Temperature 60°C

Time: 2 to 3 hours


The fabric is bleached at 80°C for 2 to 3 hours in the mentioned bleaching solution. Formic acid is added as required to maintain a pH of 3.8 to 4.2. However, care must be taken so that the polyester is not damaged by alkali. Blended fabrics can also be bleached by hydrogen peroxide at (J-Box) at 70°C.

Bleaching process of polyamide:

Most polyamide fiber bleaching is done by sodium chlorite. The ability of sodium chlorite to bleach polyamide fibers is better than that of hydrogen peroxide. This means that the fiber is white by sodium chlorite and the fiber is not likely to be damaged.


 Sodium chloride (60%) ⇒ 0.5 to 2 lbs. / 100 gallons

Acetic or formic acid ⇒as needed to maintain pH 3.8 to 4.2

The ratio of product to liqueur⇒from 1:20 to 1:40

Processing time⇒ 30 to 60 minutes

Temperature ⇒79°C to 85°C


Using 2 to 1 pound / 100 gallon of tetrasodium pyre phosphate in the mentioned solution will buffer the solution. If the bleaching vessel is made of stainless steel, 1 to 2 pounds of sodium nitrate per 100 gallons of solution is added to protect it from rust. Acetic acid or formic acid is added as required to keep the pH of the solution at 3.8 to 4.2.

The product is bleached at a temperature of 79°C to 85°C for 30 to 60 minutes. At the end of bleaching, the product is washed first with hot water and then with cold water. The residual chlorine is finally removed by washing with sodium disulfide solution at a temperature of 30°C.

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