Garments Bleach wash | denim Bleach wash Process

Bleach wash is the process of creating fading effect on the garments by use of bleaching agents. The

bleaching agents generally cut the bond of coloring particle with the fabric, thus freeing them, creating a faded outlook. The bleaching agents generally used in garments washing process are:

1. Bleaching powder
2. Sodium Hypochlorite
3. Hydrogen per oxide

The bleaching agents are serially put as per as their bleaching strength, we start with bleaching powder for mild bleaching and for better bleaching. Normally for garments fabric dyed with direct dye or reactive dye we use bleach wash for fading.

Why Washing is Necessary:

·         Remove size particles from garments.

·         To create a overall fading effect on garments

·         To create softness Garments for user.

·         To create a prominent fading effect that easily detectable.

·         Create a new fashion for gents.

STANDARS RECIPE FOR WASHING (100 KG DENIM GARMENTS):

1.     Step-1: Desizing:

·         Firstly 1:5=500L water load in the washing machine.

·         Next add the garments in the machine and start the machine to run for 2-3 minutes, in this time the garments will be properly soaked by water and will take the chemical uniformly.

·         Raise the temperature to 60°c by steady steam supply.

·         Add the desizing enzyme (cellules enzyme 1.5%=1.5kg) and run the machine for 20-25 minutes.

·         In this time the enzyme break down the long starch-Molecules into smaller ones that can be easily washed away.

·         The temperature of the wash bath is raised to 85-90°C. By this process the enzyme in the wash bath will be deactivated.

·         Lastly Liquor is drained off.

2.     Step-2:rinsing

·         The reason rinsing is optional because the next step is bleaching in which any remaining starch materials will be dissolved. So they don’t create any more problems.

·         Add 1:2/3=200/300 L water

·         Raise the temperature of the wash bath to 40°C and wash for 5-7 minutes.

·         By this the loose starch particle & other adjacent impurities will be washed out away from the garments.

·         Drain off the liquor.

3.     Step:3:bleaching

·         Add 1:5=500 L water in the machine, run the machine for 2/3 minutes then add the following chemicals gradually over 5 minutes.

·         Caustic soda------------2%----------2 KG.

·         Hydrogen peroxide---5ml/L-------2.5 L.

·         Stabilizer----------------2/5ml/L-----1.25 L.

·         Soda ash-----------------2%-----------2 KG.

·         Time X Temp-------------------------70 Minutes X 80°C

·         Check for desired fading effect after 50 minutes & when it is achieved the washing process is stopped and liquor is drain off

4.     Step-4:Rinsing

·         Add 1:2=200 L water.

·         Raise the temperature of the wash bath to 40 C and wash for 5-7 minutes.

·         By this process the loose color particles and other adjacent impurities will be wasted away from garments.

·         Drain off the liquor.

5.     Step-5: Neutralization:

·         Add 1:5=500 L water

·         Add acetic acid 2ml=1 L to the liquor.

·         Wash for 5-7 minutes at room temperature.

·         By this process the additional bleach present in the garments after wash will be removed & the PH level of the garments will be controlled at 6.8-7.2

·         It is an important process because if the extra bleach is present in the garments then after storing it for 15-30 days yellow color stain will be developed in the garments due to chlorinization/oxidation.

6.     Step-5:softening:

·         Add 1:3= 300 L water.

·         Add softener (silicon) 0.5%-1%=500ml-1 L softener.

·         Wash for 5-10 minutes at room temperature.

·         Drain off the liquor.

·         By this process the garments will possess a soft hand-feel.

·         Washing Mechanism

·         During the washing process hydrogen peroxide produces per hydroxyl ions, this takes part in bleaching action stripping colors of the fabric resulting into fading effect of the garments color.

·         Presences of the stabilizer in the wash bath ensure the steady production of per hydroxyl ions because over 80°C the peroxide is exhausted very quickly.

·         Soda ash is used in the liquor for maintaining the PH level at 10-11.

7.     Variables:

·         Depending on the extent of the fading effect the following variables are present:

·         1% of chemical: for higher range of 6%.

·         Liquor temp: maximum of 95°C.

·         Washing time: 55-85 minutes.

Advantage:

·         Easily performed on the garments.

·         Comparatively low cost.

·         Available in the market.

·         High efficiency for washing effect.

·         Need less time to wash.