Sulphur dyes are non-ionic dyes that contain sulphur linkages, are water insoluble, and produce reasonably cheap and light/wash fast shades. They are applied to cellulosic fabrics in a reduced, anionic state and oxidized after dyeing to reform the non-ionic structure and attach the dye physically to the fabric through aggregation. Sulphur dyes are classified based on their chemical structure and application, and are commonly used in powder, grain, dispersed powder, and paste forms. They are mainly used for cotton, hemp, and viscose to produce bright and brown shades through an exhaust dyeing process using reducing agents like sodium sulphide.

1. Sulphur Dyes
Sunvi Ahmed
ID: 172-091-0-155

2. Introduction
Sulphur dyes are non-ionic, possess
sulphur linkage, are water insoluble and
produce shades that are reasonably
cheap and wash and light fast. Dyes are
applied in reduced and solubilized
anionic state possessing affinity for
cellulosics. After dyeing, oxidation is
carried out to restore parent non-ionic
dye structure; sulphur dye-cellulose
attachment is established through
physical forces with dye aggregation
occurring in situ . (1)

3. Why sulphur
dyes called
sulphur dye ?
In 1873 Sulphur dyes was discovered and its
name was ‘Cacho de Laval’, after few years they
saw this dyes carried organic vegetable matter
which is sodium sulphide and sulphur. That’s
means it’s contain di-sulphide (s-s) linkage in
their chemical structure. The dyeing process is
carried out in an alkaline condition.
(2)
Dye-S-S-Dye
Chromophore Disulphide linkage Chromophore

4. Properties of
sulphur dyes
Properties of sulphur dyes:
i. Sulphur dyes is water insoluble
ii. It needs solubilization for application ( with
reducing agent)
iii. Oxidation is needed for final colour
development
iv. Applicable in alkaline condition
v. Electrolyte can be added in the dye to enhance
exhaustion of dyes
vi. Firstness properties are average
vii. Its exhaustion properties are good. (3)

5. Classification of
Sulphur Dyes
Sulphur dyes are classified according to
chemical structure and application.
• CI sulphur dyes
• CI leuco sulphur dyes
• CI solubilized sulphur dyes
• CI condensed sulphur dyes
(4)

6. Commercial
forms of
sulphur dyes
• Powders,
• Grains,
• Dispersed powders,
• Dispersed pastes, and
•Water soluble-brands
(5)

7. Method &
Mechanism of
sulphur dyes
Sulphur dye is water insoluble, but for solubilisation we normally
used sulphide Reducing agents. Like as Na2S, FeS etc. We can also
used non-sulphide reducing agents, like as Glucose, Fructose,
Invert sugar, Molasses. And if we used non-sulphide reducing agent
for sulphur dyeing process then the wash fastness is good according
to the ISO wash fastness method 3.
The most popular sulphur dyeing method is Exhaust Method.
because of the problems encountered are easily remedied: better
diffusion and uneven dyeing can usually be repaired just by re-
dyeing in the same bath or in a blank NaS bath at boil.
(6)

8.  Sulphur dyes are mainly used for cellulosic fiber products for
producing bright and brown shade. Like as cotton, hemp, sisal.
 Also used for viscose fiber products
Used of Sulphur
Dyes
The sulphur blacks are especially adapted for the
dyeing of fast blacks on hosiery, as also are the
brown colors, as the dyestuff stands the repeated
washings and the effect of the acid perspiration to
which the color of hosiery is subjected. But now:-
(7)

9. Sulphur dyes are on of the most used for producing bright and brown
shade on cellulosic fiber products. Mainly used for cotton, hemp,
viscose fabric dyeing, and can also be used to top and viscose fiber
protoplasmic coloring. Sometimes also used in leather and paper
dyeing. Sulphur dyes is used both in dyeing and printing.
Conclusion

10. Reference
1. Page-466, Chapter-14, Abstract, Chakraborty 2011
2. Page-143, The chemistry of textile and pottery, Franklin Institute
3. Page-467, 14.2, Handbook of textile and industrial dyeing
4. Page-471, 14.5, Handbook of textile and industrial dyeing
5. Page-471, 14.5, Handbook of textile and industrial dyeing
6. Page-2 & 3, Indian Journal of Fibre & Textile Research
7. Page-146, The chemistry of textiles and pottery, Franklin
Institute