Name of the Experiment: Dyeing of 100% cotton fabric with reactive dye to produce combined shade.
Introduction :
Reactive dyes are a class of highly colored organic substances, primarily used for tinting textiles, that attach themselves to their substrates by a chemical reaction that forms a covalent bond between the molecule of dye and that of the fibre. The dyestuff thus becomes a part of the fibre and is much less likely to be removed by washing than are dyestuffs that adhere by adsorption. The most important characteristic of reactive dyes is the formation of covalent bonds with the substrate to be coloured. Fiber reactive dyes are the most permanent of all dye types. Unlike other dyes, it actually forms a covalent bond with the cellulose or protein molecule. Once the bond is formed, what you have is one molecule, as the dye molecule has become an actual part of the cellulose fiber molecule.
Objective :
Ø To learn about dyeing process of cotton fabric by reactive dye.
Ø To dye cotton fabric by reactive dye.
Ø To make a combined shade using red, yellow, blue color substances.
Ø To write a report according to the experiment.
Nature of the sample :
- Pre-treated 100% cotton knitted fabric.
Apparatus Required :
- Beakers.
- Glass Rod.
- Pipette.
- Measuring Cylinder.
- Digital Balance.
- Tri-pod stand.
- Gas Burner.
- Thermometer.
- Pot.
Process Sequence :
Collection of pre-treated sample
↓
Set water level
↓
Add leveling agent
↓
Add dye solution
↓
Add salt solution
↓
Add soda ash solution
↓
Add fabric sample
↓
Raise the temperature to 60deg C
↓
Run time for 30 minute
↓
Bath drop
↓
Rinsing
↓
Hot wash at 90deg for 10minute
↓
Drying
Dyeing Recipe has been shown in the table: 1.1
|
SL
|
Process Parameter
|
Unit
|
Dossing
|
Stock Solution
|
|
01
|
Levelling Agent
|
g/L
|
1
|
1%
|
|
02
|
Sequestering Agent
|
g/L
|
1
|
1%
|
|
03
|
Reactive Red
|
%
|
0.5
|
1%
|
|
04
|
Reactive Yellow
|
%
|
0.5
|
1%
|
|
05
|
Reactive Blue
|
%
|
1
|
1%
|
|
06
|
Glauber Salt
|
g/L
|
40
|
15%
|
|
07
|
Soda Ash
|
g/L
|
10
|
10%
|
|
08
|
Sample Weight
|
gm
|
5
|
---
|
|
09
|
M:L
|
-----
|
1:30
|
---
|
|
10
|
Temperature
|
°C
|
60
|
---
|
|
11
|
Time
|
min
|
20
|
----
|
Function of Chemicals :
Levelling Agent:
Ø Control of the exhaustion dye so that it is taken up evenly.
Sequestering Agent:
Ø Sequestering agents or Chelating agents remove metal ions from a solution
Ø These agents are used to eliminate water hardness and heavy metals, such as iron and copper which can affect the process.
Reactive Dye:
Ø Main substances to produce color.
Glauber Salt:
Ø The salt in the reactive dyeing increases the affinity of the dye towards the Cellulosic substrate.
Ø Salt increases the exhaustion rate of reactive dyestuffs.
Ø As reactive dyestuffs have a lower affinity, more inorganic salt is required when using reactive dyestuffs in order to accelerate absorption.
Soda Ash:
Ø Reactive dyeing required alkali medium, Soda ash control the pH of the dye bath.
Calculation :
Total Liquor: Material Weight X L { M:L }
= 5gm X 30
= 150 mL
` Levelling Agent: = (150 X 1)/(1% X 1000) mL
= 15mL
Sequestering agent: = (150 X 1)/(1% X 1000) mL
= 15mL
Glauber Salt: = (150 X 40)/(15% X 1000) mL
= 40mL
Soda Ash: = (150 X 1)/(1% X 1000) mL
= 15mL
Reactive Red: = (5 X 0.5%)/(1%) mL
= 2.5 mL
Reactive Yellow: = (5 X 0.5%)/(1%) mL
= 2.5 mL
Reactive Blue: =(5 X 1%)/(1%) mL
= 5 mL
Initial Water : = Total Liquor - (chemicals)
= 150 - (15+15+40+15+2.5+2.5+5)mL
= 55mL
Process Curve :
Figure 1.1 : Process Curve
Sample Attachment & Observation :
Figure: 1.2
Comments : The fabric absorbed dyes particle very well and turns into violate color.
