Study on CPB dyeing of 100% cotton woven fabric with light shade color ocean.

 Experiment No : 06.

Experiment Name:

Study on CPB dyeing of 100% cotton woven fabric with light shade color ocean.

Introduction:

Cold Pad Batch Dyeing is one of the widely used semi-continuous dyeing process. It is mainly used in the dyeing of cellulosic fiber like cotton or viscose (knit and woven fabric) with reactive dyes. 
Now a days this process widely used in our Woven dyeing industry and it is a development process for Knit dyeing industry in Bangladesh. It is primarily a cold method where the dyeing temperature is 20-25°C and use Cold to Medium Brand Reactive Dyes, 
and so it is called Cold Pad Batch (CPB) Dyeing. Cold Pad batch dyeing is a process that offers some unique advantages.Like low cost, energy saving etc.

Objective :

•   1. To achieve a uniform and light ocean shade on 100% cotton woven fabric using the CPB dyeing process.
•   2. To evaluate the efficiency of dye fixation and shade development.
•   3. Evaluate the colorfastness of the dyed fabric to various factors like light, washing, and rubbing.

Raw Materials: 100% cotton knitted fabric.

Chemical Required: 

              

               Dye 

               Fixing Agent        

                     Salt (NaCl)
                     Soda ash (Na2CO3)
                     Sequestering agent
                     Levelling agent
                     Wetting agent 

Apparatus Required :

•       Beakers.
•         Glass Rod.
•       Pipette.
•      Digital Balance.
•      Pot.
•     Air dryer.

Recipe:

          Dyes                         : 1 %

          Fixing Agent             : 1.0 gm/l

          Salt (NaCl)                : (40-60) g/l

          Soda ash (Na2CO3)  : (10-15) g/l

          Sequestering agent   : 0.50 g/l

          Anti-creasing agent   : 1.0 g/l 

          Levelling agent          : 1.0 g/l

          Wetting agent            : 0.5 g/l   

           M : L                         : 1 : 10

           pH                            : 10 – 11

           Temp                        : Room temp

          

Calculation:

Fabric weight= 10 gm (total -50 gm)

Total Liquor = Material Weight X L { M:L }

                                  = 50 gm X 10

                                  = 500 mL

Dyes = (2 X 50) ÷ 100

          = 1 gm

Fixing agent = (1 X 500) ÷ 1000

                     =0.5 gm/l

Salt(NaCl) = (60 X 500)÷ 1000

                  = 30 ml

Soda Ash = (15 X 500) ÷ 1000 

                 = 7.5 ml

Sequestering agent =(0.5 X 500) ÷ 1000 

                                = 0.25 ml

Anti-creasing agent =(1 X 500) ÷ 1000 

                                 = 0.5 ml

Levelling Agent = (1 X 500 )÷1000 

                         = 0.5 ml

Wetting agent =(0.5 X 500) ÷ 1000 

                       = 0.25 ml

Water required = Total Liquor - (chemicals)

                     = 500 - 40.5

                     = 459.5 mL

Working Procedure:

    Fabric Preparation:

1. Desize, scour, and bleach the cotton fabric to remove impurities.

    Preparation of Dye Solution:

1.  Prepared solution of all the chemical like: sodium carbonate, leveling agent, and wetting agent.

Padding Process:

1. Dip the fabric into the prepared dye solution.
2. Pass the fabric through the padding mangle rollers to achieve uniform dye pickup.
3. Adjust the pressure to ensure 70–80% wet pickup.

Temperature

1. Dye at room temperature (20–25°C).

Post-Dyeing Wash:

1. Wash the fabric with cold water to remove unfixed dye.
2. Conduct a final rinse with cold water.

Drying:

1. Dry the fabric using a air dryer.

Result:

Fabric sample 

Conclusion:

     

   The CPB dyeing process effectively achieves a uniform light ocean shade on 100% cotton fabric. The method’s low-temperature processing and minimal energy requirements make it a sustainable approach for reactive dyeing. Proper control of process parameters ensures excellent color fastness, shade uniformity, and fabric quality.

Precautions:

1. We use deal with chemicals use hand gloves. 

2. Carefully mix all the chemical with water. 

3. Maintain correct padding pressure to prevent streaks.

4.Follow safety guidelines for operating the dyeing machine.