faults causes, remedies of sulphur dyes

  Sulpher dyes faults causes, remedies, and precautions:

In this blog, I am going to discuss the faults causes, remedies, and precautions of sulphur dyes.

1. During dyeing with sulpher dye if the fabric comes to contact with air then it completes oxidation and makes Sulphuric acid which destroys the dye's dyeability and damages the fabric. We should take care during dyeing that the fabric must not come to contact with air. For this purpose need to sink fabric in the dye solution. 

2. If we dye woolen fabric with sulfur dye then the fabrics may be damaged. The aqueous of this dye is most Alkali which can destroy woolen fabrics. If we dye cotton and wool then we can get a very dark black color. In this case, cotton fiber can neutralize alkalis. As a result, cotton fiber is dyed and wool fiber is not damaged. 

3. When we dye cellulosic fiber with sulphur dye then it may create sulphuric acid. As a result, it creates tendering effect. To remove this happening we need to follow the below step. 

The fabric that is dyed by sulpher dye needs to treat at 50-70°C, in 1-3% Potassium dichromate for 30 minutes to remove tendering effect. 

4. Bronziness effect: If we use less quantity of sodium sulfite then it can happen bronziness effect. To remove this effect we need to treat the dyed fabric in 0.1% sodium sulfite solution for 10-15 minutes at 60°C. As a result, it reduces excessive dyes on cotton fabric. 

5. If we take stock of sulpher dyed fabric then it can reduce fabric strength or fabric can be damaged. The main cause is the moisture, which reacts with dyestuff and produces sulphuric acid which reduces the strength of the fabric. 

To prevent this damage we need to dry the fabric with slight sodium acetate when dry the fabric. We can take an after-treatment process of 1-3% potassium dichromate and an equal quantity of acetic acid need reaction at 60°C for 30 minutes.

Precautions for sulpher dyeing: 

1. The dye bath should be copper. 

2. Should be a controlled reduction process. The excessive reduction can reduce the rate of dye exhaustion. As a result, the shade becomes weak and a waste of dyes.  

3. During the dyeing process it should not enter the air in the dye bath that shout be maintained. Otherwise, it will produce oxidation and shade may be faulted. 

4. It should not continue the dyeing process at high temperatures. 

5. After unloading dyed fabric from the dye bath and washing process if delayed then it can cause bronzing.  

6. High temperatures also can create bronzes.