About sulphur dyeing

Helo, reders today I m going to explain about Sulphur dyeing.
I m writing all information about Sulphur dyeing process with my personal view.

• Introduction

• Sulphur dyeing

• Sulphur dyes charactrisitics

• Sulphur dyes properties

• Sulphur dyeing recipe

• Sulphur dyeing process

• Sulphur dyeing faults

• Sulphur dyeing remedies

• Sulphur dyes advantage

• Sulphur dyes disadvantage

• Sulphur dyes Uses

Introduction of Sulphur dyeing

Sulphur dyes are more profitable and valuable for cellulose fibres.
Sulphur dyes have ability to produce deep shade products. Sulphur dyes is also use for printing.

Sulphur dyes is 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 aggent or more.

Sulphur dye having ability to produced heavy materials such as rubber materials or more.
Wool production is not possible or proteins fibres.

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

Sulphur dye is used for
yarn dyeing process, cotton fabric dyeing, and denim fabric dyeung also.

sulphur dyeing

– Sulphur dyes is more suitable and profitable dyes for cellulose.
– Sulphur dyes are more popular for black and brown shade production.

sulphur dyes characteristics

In case of Sulphur dyeing here the main characteristics given below

– oxidation chemical treatment is requird for colour and shade devlopment.

Sulphur dyes is more popular for deep shade.

– washing fastness is good because the dye partical 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 dobe properly because sulphur dyes contain  dye -S -S – dye

– Di-sulphide

dye – S-S – dye

/   Di sulphide

Chromophor       Chromophor

– 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.

sulphur dyes properties

– Sulphur dyes are insoluble in water.
– Sulphur dyes have no effinity 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 also used in 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.

Sulphur dyeing 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 Fuction in Sulphur dyeing

1. 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. 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. Sequistering agent

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

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

4. 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

https://textilesgreen.blogspot.com/?m=1

• 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 fults 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

Sulphur dyes advantage

• 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.

Sulphur dyes Disadvantages

• 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.

Sulphur dyes Uses

• 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.

Read more articles

• All information of sulphur dyeing

Reactive dyeing properties

Reactive dyeing types

Reactive dyeing recipe

Thank you

Categories: Fabric Dyeing

0 Comments

Leave a Reply

Your email address will not be published. Required fields are marked *