Application process of Soluble sulphur dyes

  Soluble sulpher dyes Application process:

Application of soluble sulphur dyes is an important topic. Generally, sulpher dyes are insoluble in water. But there are some sulpher dyes that are soluble in water. In sulpher dyes classification, it is in the fourth class dye. These types of dyes are soluble in water and have more absorbency on cotton fiber. These dyes are in the category of solubilized dyes. These dyes are compounds of insoluble sulpher dye and reducing agent added compound. Examples of these dyes are given below: 

1. Immedical leuce blue PGI

2. Immedical leuce Navy blue 6RCF

3. Immedical leuce yellow 36GT

4. Immedical leuce green FFG

5. Immedical leuce dark green 

The recipe is given below: 

Dyestuff: 2-10% based on the shade and based on the weight of the fabric 

Sodium chloride: 15-40% based on the weight of the fabric.

Glubar salt: 1-8% based on the weight of the fabric. 

Soda Ash: 1-4% based on the weight of the fabric. 

Water: 30 times based on the weight of the fabric. 

Temperature: 25-30°C

Time: 45-60 minutes

Dyeing process: First of all need to take some water in a pot. Then mix the dyestuff in it and make a dye paste. After that give the necessary amount of water and mix well. After that need to mix sodium chloride and next add soda ash. Then need to dye at 25-30°C for 45-60 minutes.    

After treatment of sulpher dye: 

After treatment is very necessary for any dyeing. So here also we will do after treatment to fix up dyes and remove unfixed dyes.

For dyed cotton fabric, we need to add peroxide 0.5-1% and need to raise the temperature to 60-70°C for 5-10 minutes then shade brightness will be good. 

To increase washing fastness after dyed fabric needs to use potassium dichromate and acetic acid. The recipe is given below: 

Copper sulfate: 2% based on the weight of the fabric. 

Potassium dichromate: 2-3% based on the weight of the fabric.

Acetic acid: 3-5% based on the weight of the fabric.   

Temperature: 50-60°C

Time: 15 minutes. 

To increase washing and light fastness we need to add 0.5-1.5% potassium dichromate, 1-3% Copper sulfate, and 2-5% acetic acid(Concentration 30%), temperature needs 50-70°C. Here time will be 5-10 minutes. After that need to wash in normal water.  

If after dyeing shade is not accurate then we check the tolerance. If the shade is out of range then we need to do stripping. To perform this we need a chemical named Albigin A or Polyvenyle pyrrolidone. In the presence of this any one chemical need to treat the fabric in a sodium sulfite solution. If we can not get results then we can do bleaching in sodium hypochlorite bleaching. Sometimes we use potassium permanganate also to bleach and remove dyes slightly and then also dye accurately.  

Topping: By doing topping we can do accurate shade and can reduce shade problems. Can be mentioned that Sulpher dye can use as a mordant of basic dye. Unevenly dyed cotton or cellulose fabric can be dyed with basic dye to get an accurate shade. In this need to wash the fabric with sulpher to remove alkali and then dye with basic redyeing in 60°C.