Dyeing of 100 % cotton fabric using vat dyes by pad dye continuous method (Pad jig method).

Abstract:

The experiment was performed in textile processing laboratory. Dye solution was prepared according to the recipe and sample was padded through. Later color was developed by using jigger machine.

Introduction:

Vat dyes are predominantly used for dyeing cellulosic fibers and the cellulosic component in polyester/cellulosic blends. Dyeing with vats depends on converting the water-insoluble vat dye by reduction to the water-soluble leuco compound. This has substantivity for cellulose and is therefore absorbed by the fiber. After dyeing, the leuco compound is converted back to the original insoluble form by oxidation.

Objectives:

1. To understand the application method of vat dyes by pad jig method.
2. To achieve uniform dyeing on jigger machine.

Equipment and Materials:

• Beaker
• Stirrer
• Measuring cylinder
• Weighing balance
• Dye
• 50 % NaOH
• Hydros
• Dispersing agent
• Wetting agent
• Anti-migrating agent
• Salt
• Hydrogen peroxide

Recipe:

Dye Pad Solution
Serial No.	Chemical	Concentration
1	Dye	40 g/l
2	Wetting Agent	2 g/l
3	Sequestering Agent	2 g/l
4	Dispersing Agent	2 g/l
5	Anti-migrating Agent	5-10 g/l
Jigger Development
1	NaOH	50 g/l
2	Wetting Agent	2 g/l
3	Sequestering Agent	2 g/l
4	Dispersing Agent	2 g/l
5	Hydros	25 g/l

 

Procedure:

• Fabric sample was cut in appropriate size and weighed.
• Dye solution was prepared according to above recipe.
• Fabric sample was padded through the solution.
• After padding fabric was dried at 110 ˚C.
• Solution was prepared for jigger machine.
• Fabric was adjusted in jigger and solution was poured in to the machine.
• Fabric was heated to 80 ˚C in 45 minutes.
• Then solution was drained and hydrogen peroxide was added at 60 ˚C for re-oxidation of the dye for 20 minutes.
• After 20 minutes sample was taken out and washed with detergent solution.

Results and discussion:

• The fabric was dyed successfully without any un-levelling.
• Semi continuous process takes more time.
• Dark shades are obtained by this method.
• Good fastness properties were obtained.