Monday, March 13, 2017

Cotton Garment Dyeing with Direct Dyes

Garment dyeing process:
Garment dyeing is a comparatively new technology for us. In this process solid color garments is dyed after making garments from the grey fabric. This is comparatively lower cost dyeing than that of fabric dyeing process and it takes less time. In this system no possibility of shade variation within the garments. By this process old garments can be re-dyed. 
 
Garment dyeing
Fig: Garment dyeing
Objectives:
  • To dye the solid color garments in grey form
  • To save the dyeing cost and time
  • To increase the production efficiency
  • To get exact shade in different pans of the garments
  • To avoid delay of bulk order delivery
  • To wash the garments after dyeing
Equipments:
For garments dyeing there is not necessary for any elaborate machine. Here all the pre-treatment, dyeing and finishing could be produced at same machine.
  1. Garments dyeing machine (Rotary dyeing machine)
  2. Garments washing machine
  3. Hydro-extractor
  4. Garments dryer
Raw materials:
Here raw materials are:
  1. Cotton garments made from grey fabric
  2. Common salt
  3. Detergent
  4. Desizing agent
  5. Caustic soda
  6. Wetting agent
  7. Hydrogen per oxide (H2O2)
  8. Stabilizer
  9. Sequestering agent
Garment dyeing flowchart:
Process sequence the dyeing of cotton garments with direct dyes.
Desizing
↓ 
Scouring and bleaching
↓ 
Washing off
 
Neutralization
↓ 
Dyeing
↓ 
Washing off
 
Softening
Delivery

Desizing recipe:
  • Garments ------------------------- Xpcs
  • Desizing agnt -------------------------- 2 g/L
  • Wetting agent -------------------------- 1 g/L
  • M:L ratio ---------------------------------- 1:8
  • Temperature -------------------------------- 80-900C
  • Time ------------------------------------ 20-30 min
Scouring and bleaching recipe:
  • Garments ---------------------------- Xpcs
  • Caustic ------------------------------- 12%
  • H2O2 --------------------------------6%
  • Stabilizer -------------------------2%
  • Wetting agent -------------------1%
  • M:L --------------------------------1:8
  • Temp ----------------------------85-900C
  • Time -----------------------------90 min
Washing off recipe:
  • Garments -----------------------Xpcs
  • Softener -----------------------2 g/L
  • M:L ----------------------------1:8
  • Temp ------------------------600C
  • Time -------------------------5 min
Neutralization recipe:
  • Garments ------------------Xpcs
  • Acetic acid -------------------1%
  • M:L ----------------------------1:8
  • Temp -------------------------85-900C
  • Time --------------------------10 min
Dyeing recipe:
  • Garments ------------------------Xpcs
  • Direct dye ------------------------1-3%
  • Common salt --------------------40%
  • Sequestering agent ------------1%
  • Soda ash --------------------------5%
  • M:L -------------------------------1:8
  • Temp ----------------------------70-800C
  • Time -----------------------------60-70 min
Washing off recipe:
  • Garments ---------------------Xpcs
  • Detergent --------------------2 g/L
  • M:L -----------------------------1:8
  • Temp --------------------------600C
  • Time ---------------------------5 min
Softening recipe:
  • Garments --------------------Xpcs
  • Detergent -------------------1-2 g/L
  • M:L ---------------------------1:8
  • Temp ------------------------30-400C
  • Time -------------------------15-20 min
Then unload the garments and process the following:

Hydro-extract the garments 
↓ 
Dry the garments 
↓ 
Iron the garments 
↓ 
Delivery the garments  
 
Precaution to be taken before garments dyeing:
  • Garments to be dyed required design to be used should be considered from engineering point of view. 
  • If elastic materials are used in the garments then that elastic materials may loss their elastic power or properties. 
  • If there are knitted and woven fabric in the same garments then after the garments dyeing the knitted fabric may shrinkage more than that of woven and there will be seam puckering problems in the garments and garment will be faulty and that will be rejected. 
  • If the garment or grey fabric is made from mixed fiber such as cotton and viscose then the two fibers will not absorbed same dye and then there will be a shade problem after dyeing.
Results:
After completing this experiment we got a washed look dyed garments.

Conclusion:
Now a days garments exporting business is going much competition in the world where there is a big fact is the time for the shipment of the garments to the buyer and as we have no direct root to export to the American or European market so we need more time to reach there so we have to be fast in out production and we have to offer less price in the market. So by considering above all mentioned point we have to use garments dyeing technique which make the process shorter.