About sulphur dyeing
• 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 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 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
– dyeing is dobe properly because sulphur dyes contain dye -S -S – dye
dye – S-S – dye
/ Di sulphide
– Sulphur dyes are reoxidized after dyeing by air.
– hydrogen peroxide is also used for oxidation in sulphur dyeing.
– No more costly process
sulphur dyes properties
– 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
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
Here, if tendering broblme will occur on the fabric. then wash properly with CH3COONa.
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.
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
• Sulphur dyes is not used directly for dyeing, dye is converted to leuco form with some useful chemicals such as dilute aqueous na2s.