Name of The Experiment: Estimation of Scouring effect by weight loss.
1. Objective:
- · To learn about the estimation process of scouring effect by weight loss method.
- · To scouring a piece of grey fabric.
- · To determine the scouring effect by weight loss method.
2. Theory:
Scouring is the pre-treatment process of wet processing technology. Scouring is the first stage of pre-treatment. Before dyeing or printing of textile materials must pass scouring process. Scouring is the process by which natural (oil, wax, gum, fat etc) as well as added (during fabrication process) impurities are removed completely as possible. Especially hydrophobic character which is present in the fiber of fabric is removed by this process. Like consider cotton fiber which contains 96-97% cellulose and rest others are impurities. Basically in case of weight loss 4-5% loss of weight may consider as standard due to scouring.
Weight Loss = (Weight Before Scouring-Weight After Scouring) / ( Weight Before Scouring X 100 )%
3. Experimental Procedure:
Sample: 100% cotton knitted gray fabric.
Dyes & Chemicals:
Table 1.1: List of dyes and chemicals
Name of chemicals
|
Function
|
Detergents
|
Reduce surface tension of water, active cleansing action
|
Caustic Soda
|
Main chemical to remove (Oil, fat, wax)
|
Sequestering Agent
|
Deactivate metal ions in water
|
Equipment List:
o Beaker.
o Measuring Cylinder.
o Pipette.
o Pot.
o Tri-pod stand.
o Gas Burner.
o Pot.
o Digital Balance.
o Scissor.
o Match Box.
4.Working Procedure:
Table 1.2: Scouring Recipe
SL
|
Process Parameter
|
Unit
|
Dossing
|
Stock Solution
|
01
|
Detergent
|
g/L
|
1
|
1%
|
02
|
Sequestering Agent
|
g/L
|
1
|
1%
|
03
|
Caustic Soda
|
g/L
|
3
|
3%
|
04
|
Sample Weight
|
gm
|
5
|
---
|
05
|
M:L
|
-----
|
1:30
|
---
|
06
|
Temperature
|
°C
|
95
|
---
|
07
|
Time
|
min
|
20
|
----
|
Calculation:
Total Liquor: Material Weight X L { M:L }
= 5gm X 30
= 150 mL
Detergent: = (150 X 1)/(1% X 1000) mL
= 15mL
Sequestering agent: = (150 X 1)/(1% X 1000) mL
= 15mL
Caustic Soda: = (150 X 3)/(3% X 1000) mL
= 15mL
Initial Water : = Total Liquor - (chemicals)
= 150 - (15+15+15)mL
= 150-45 mL
= 105mL
Process Flow Chart:
Collection of 100% cotton grey fabric.
↓
Measure Weight of the fabric.
↓
Scouring the fabric as per recipe.
↓
Dry the fabric.
↓
Again weight the fabric and calculate weight loss.
Figure 1.1 : Process Flow Chart
Figure 1.2: Process Curve
At first we need to collect grey cotton fabric, measure its weight and noted as a weight before scouring. Then we have to set dye bath at room temperature add water as per recipe and other chemicals as per recipe. After added all chemicals we have to add the grey fabric sample and raise the temperature to 95°C. We have to hold the temperature for 20 minutes to achieve standard scouring, then we dry the fabric and measure its weight again to estimate the scouring.
Precautions:
o Taking chemicals as per recipe provided by the Instructor.
o Taking every weight of chemicals carefully.
o Switch off the safety system of gas cylinder after complete the experiment.
5. Result & Discussion:
Estimation of Scouring:
Weight before scouring: 4.738gm
Weight after scouring: 4.624gm
Weight loss: (Weight Before Scouring-Weight After Scouring) / ( Weight Before Scouring X 100 )%
=(4.738gm-4.624gm)/(4.738gm X 100 )%
= 2.40%
Discussion: We observed here the weight loss is 2.4% due to scouring. But the standard range is about 4-8%. So we can say the scouring is not about enough compare to standard range.
6. Conclusion & Comments: By doing this experiment we have learned about the scouring process of cotton fabric and estimate the scouring by weight loss method. We are unable to achieve standard scouring effect to the given sample due to less time or less concentration of chemicals in our recipe.
