Brief on denim bleach wash process

Bleach Wash:

Bleach wash denotes to light blue shades of denim fabric.  The subordinate step is bleaching to stone wash. This bleaching is usually carried out by a strong oxidizing agents. In textile industry, most widely used chemicals are sodium hypochlorite, calcium hypochlorite, hydrogen peroxide and chlorine. Other than that, many products with different brand names are available in the market.

 

Process of  Bleach Wash:

 

Raw materials used:

• Water
• Enzyme (Neutral powder)
• Sodium-meta bi Sulphate
• De-sizing agent
• Acetic Acid (CH₃COOH)
• Cationic softener
• Chlorine

Step 1: – Pretreatment/ De-sizing:

• Load the sample fabric
• Add water: 20 L
• Start Machine.
• Add de-sizing agent: 2gm/L
• Temperature: 40°c.
• Time: 10 min.
• Drop the liquor.
• Rinse twice for 3 minutes (cold)
• pH: 6

Step 2: – Enzyme treatment:

• Water: 20 L
• Enzyme (Neutral powder): 10%
• Temperature: 40°c
• Time: 35 min
• Drop the liquor
• Rinse twice for 3 minutes (cold)
• pH:6

Step 3: – Bleach wash

• Water: 25L
• Bleach (Cl₂ , 65%) : 20gm/L
• Temperature: 40°c.
• Time: 30 min.
• Drop the liquor.
• Rinse twice for 3 minutes (cold)
• pH: 10

Step 4: – Softening

• Water: 20 L
• Cationic Softener: 4gm
• Acetic acid: 1gm/L
• Temperature: 40°c
• Rinse: No rinse
• pH: 4.5

Step 5: – Hydro-extractor machine:

• Hydro extractor machine eliminate extra water from the sample
• Time: 5 min

Step 6: – Dryer-machine:

• After hydro-extraction the garments are sent to drying m/c for complete drying.
• Time: 20 min
• Temperature: 60°c
• pH: 4.5

Step 7: – Delivery:

• After drying the samples send to quality section for checking & rectify washing fault and then good one delivery.

Ref.:

1. Project report of “Effects of Different Types of Wash on Denim Fabric” by Tutul Ghosh, Junayed Hossain Chowdhury & Amit Ghose under supervision of Md. Aswad Al Haque Sarker, Lecturer, Department of Fabric Engineering, Bangladesh University of Textiles
2. https://textilelearner.blogspot.com
3. www.slideshare.net
4. Photo by Karolina Grabowska from Pexels