Helo, reders today i m going to explain about exllent information of sulphur dyeing.

If you want to know in details about Sulphur dyeing process. then read complete article.

I have made this guide to help you out.

So, hold your seat and be with the end of guide.

So, you could get valuable information regarding Sulphur dyeing process, properties, dyeing process, recipe, fults and more. Let’s get started.

Read Also: – Azo dyes, azo dye test for aromatic amines, azo dye test for phenol.

Sulphur dye process

Sulphur dye process
Sulphur dye process

• Sulphur dye are more profitable and valuable for cellulose fibres.
• Sulphur dyes have ability to produce deep shade products. Sulphur dyes is also use for printing.
• Dyes are insoluble in water.
• Alkaline PH (10-11) is required for Sulphur dyeing.
• Some useful chemicals is required for improvement light fastness such as dye fixing agent or more.

• Sulphur dye having ability to produced heavy materials such as rubber materials or more.

• Wool and proteins fibres production is not possible for dyeing. 

• Sulphur dyes having not ability to produce other colour shade such as red, orange, yellow.

• Sulphur dye is used for, cotton fabric dyeing, and denim fabric dyeing also.

• Sulphur dyes is more suitable and profitable dyes for cellulose.

• Sulphur dyes are more popular for black and brown shade production.

Sulphur dye properties

– Sulphur dyes are insoluble in water.
– Sulphur dyes have no afinity for textile cellulose fibres.
– Sulphur dyes are converted to leuco form before dyeing with the help of dilute aqueous (na2s).
– This leuco form is used for dyeing of cellulose materials.
– Sulphur dyes develop s-s linkage in chemical structure.
– Sulphur dyes are produced black and brown shade.
– Sulphur dyes are used and it’s give great results in case of different types of textile printing.

– Sulphur dyes are insoluble in water.

– Sulphur dyeing is favourable cost structure.

– Alkaline condition is required for dyeing.

– Sulphur dyeing is one of the most popular for black, brown and blue shade production.

– Sulphur dyes are not more costly process.

– electrolyte is used for exhaust dyes.

– After treatment is required for shade development.

– oxidation treatment is required for shade development in case of Sulphur dyeing.

– Striping is required for uneven dyeing.

– Sulphur dyes is also used for dyeing and printing. 

Read more: resonating structure of nitrobenzene?

Read more: Miscible liquids and immiscible liquids?

Sulphur dyes characteristics

In case of Sulphur dyeing here the main characteristics given below

– oxidation chemical treatment is required for colour and shade development.

–  Sulphur dye is more popular for deep shade.

– washing fastness is good because the dye particle of sulphur dye is big and insoluble in water

– In case of sulphur dyes, dye particle of sulphur dye is converted into leuco form with the treatment of dilute aqueous Na2S.

– dyeing is done properly because sulphur dyes contain  dye -S -S – dye

– Di-sulphide

dye – S-S – dye

/   Di sulphide

Chromophore       Chromophore

– Sulphur dyes are reoxidized after dyeing by air.

– hydrogen peroxide is also used for oxidation in sulphur dyeing.

–  No more costly process

– dyeing temp of sulphur dyes are 90-100°c. read more important articles such as reactive dye.
If you of ll information about reactive dye and more, available in my article. 

Sulphur dyeing recipe

recipe

Sulphur dye              –    8 – 12%

Reducing agent         –  8  g/l

Alkali (Na2CO3)        – 10 g/l

NaOH                          –  5 g/l

Salt (NaCl)                 –   10 g/l

Wetting agent            – 1 g/l

Sequestering agent  –  1 g/l

Leveling agent           – 1 g/l

Time                         –    40 minute

Temp                         –   80°c

Chemically Function in Sulphur dyeing

1. Role of leveling agent

• lower the initial rate of dyeing.

• Control the migration steps of dye.

• if the levelling agent is not use then double dye to dyed the fabric.

2. Role of Wetting agent

• Reduce surface tension with the help of wetting agent because if wetting agent is add in dye bath then it reduces surface tension, results dye is enter properly in to the fibre.

3. Role of Sequestering agent

• Sequestering agent is used during dyeing because it control increase hardness of water.
In simple water some unwanted ions are persent such as maganassim or more and this water is not proper for dyeing.

This is the reason, Sequestering agent is add in dye bath it help to remove hardness of water and it’s also remove unwanted ions.

4. Role of Reducing agent

• Reducing agent is use during dyeing because it’s help to reduce the dye molecules. and make proper leco form and it’s help for dyeing. Sodium sulfide is use as a reducing agent.
Sulphur Dyeing Process

• steps – 1

first of all add dyeing chemicals such as, levelling agent and then add wetting agent. Temp will be 40°c of bath.

• steps – 2

Add dye solutions in same temp.

• steps – 3

Introduce fabric in dyeing bath.

• steps – 4

Add 1/2 salt in dyeing bath and then raised temperature up to 60°c.

• steps – 5

Again add 1/2 salt and the again raised the temp up to 90°c. and dyeing continue at same temperature. and dyeing time will be 40 mint.

• steps – 6

And then cooling – rinsing – washing – after treatment is carried out for shade development.

Sulphur dyeing (faults)

Tendering
Bronziness

Tendering

After Sulphur dyeing, sometimes strength loss will occur. This is called tendering faults.
the main problem is tendering of Sulphur dyeing but this problem will solved by using some useful chemicals. such as CH3COONa, this is called buffer solution.
Here, if tendering broblme will occur on the fabric. then wash properly with CH3COONa.
Remedies
Wash with CH3COONa buffer solution chemicals.
Proper washing is required for this faults with buffer solution.

Bronziness

In case of Sulphur dyeing, Bronziness fults is directly related with shade change or colour change. Shade is not properly match with required shade or colour.
This is also a big faults in case of Sulphur dyeing. Shade is not matching after dyeing.
But this problem is also solved by using some useful chemicals.

Remedies

Use NaHSO3 in conjunction with NaOH and Na2S.
This is a simple process.

treat with boiling soap soon

Soaping chemicals – 1 g/l

Temp.                       – 95° to 100°c

Time.                        – 10 – 20 mint

Advantage of sulphur dye

• Textile Sulphur dyeing process is not more costly.

• Sulphur dyes having ability to produced deep shade product.

• Sulphur dyes are also used in printing.

• wash fastness and light fastness is good.

• dyeing process is done with low energy.

• Sulphur dyes are available in powder form or also soluble form.

• manufacturing process is done easily.

Disadvantage of sulphur dye

• wool dyeing is not possible.
• some useful chemicals are required for development of light fastness.
• After treatment(oxidation) is required for final shade development.• Sulphur dyes is not used directly for dyeing, dye is converted to leuco form with some useful chemicals such as dilute aqueous Na2s.

Uses of sulphur dye

• Sulphur dyes is used for all rubber materials.
• Sulphur dyes is used for cotton, and rayon fibre.
• Sulphur dyes is used for black uberlla cloth or materials.

Eco-friendly Sulphur dyeing process

The chemical structure of sulphur dye is unknown till today.
The chemical structure of sulphur dye is,
R-S-S-R , this is called Bisulphide.
Why sodium sulphide is not proper because,
• it is cheap but very bed smell.
• high COD
• it is toxic
• it contaminates sea or revert
• international standard for discharge is 2 ppm.
   
Solution to sulphide problem;
• Recovery of sulphides from effluent. But it is costly process because it requires costly equipments.
• it required to replacement of Na2S.
Replace Na2S by Glucose;
• highly unstable compared to Na2S.
• it required high pH 11- 12 .
• quantity of glucose required is about 2 times for black and 2.5 times for navy.
• Less yield of dye.
• it is costly Process.
Recipe;
Dye (past with TRO)     8%                       5%
Soda ash               equal as dye    equal as dye
Caustic soda          pH 11-12            pH 11-12
Glucose         2 times of dye        2.5 times dye
Carry out reduction at 70°C for 20 minutes, followed by dyeing at boil for 1 hour, followed by oxidation and soaping.
 
Hydrol
• it has same potential as Na2S.
•it contains 50% reducing sugars.
• cheaper then glucose
• it is byproduct of maize starch industry.
• 65 part of hydrol and add 25 parts of caustic and 100 parts of sulphur dye at 80°C at pH 10.

Frequently asked Question 

1. What is black sulfur?

Actually black sulfur is made from 2,4 dinitrophenol. these are simple process to produce sulphur black dye or colour which is use in textile materials.

2. What is ingrain dyes? 

A dyes that is formed inside a substrate by the combination of two or more chemicals that individually cannot colour the substrate is called an ingrain dye. 

For example: An azoic dye is good example of an ingrain dye. 

they are not a readymade dye but are produce by the dyer inside on the fabric from 2 components usually referred to as naphthols and bases or azoic coupling. 

3. What is relation between structure of dye and fastness properties? 

Fastness properties:- these are the prop of dyes which indicate the tolerance of the dyes on fibers towards the action of various foreign company, such as light, washing, heat, rubbing, perspiration, milling, (rotuting in wash wheel) etc. 

Light fastness of a dye on a particular fibre is expressed in terms of grade 1 –  8.

Grade  1        –      very  poor

Grade 2        –        poor

4. Classification of dyes according to the chemical structure?

Classification of dyes is as follows, 

1. Nitroso dyes                 11. Thiazole

2. Nitro    dyes                  12. Azine

3. Azo      dyes                   13. Thiazine         

4. DPM   dyes                     14. AQ

5. TPM                                 15. Indigoid

6. Xanthere                        16. Azoics

7. Acridine

8. Quinoline

10. Methine dyes

Learn more;- 

disperse dyeing process, dyeing of polyester with disperse dye. 

Thank you