Synthetic Dyes

Synthetic dyes are chemically made dye, which
have more shades of colours than natural dyes.

There are some parameters which are help to
choose the synthetic dye for suitable fibres. Now-a
–days there are many types of synthetic dyes are
available in market. Some synthetic dyes are acid
dyes, basic dyes, azoic dyes, reactive dyes,
mordant dyes, vat dyes, sulphur dyes, disperse
dyes, direct dyes, diazo dyes, etc.
•Dyes from nature were used of necessity until an accidental
discovery in 1856 launched the synthetic dye industry.
•Synthetic dyes give bright and vivid colours, many natural
dyes do not.
•An 18-year-old chemistry student, William H. Perkin,
working in August Wilhelm von Hofmann's laboratory in
London attempted to synthesize quinine and instead
discovered how to make mauveine, a purple dye. Perkin
was experimenting with a compound called aniline.
•Most of synthetic dyes are prepared from coal tar, being
formed from an aromatic hydrocarbon such as benzene,
from which indigo is derived.
The following parameters can serve as a guideline for
synthetic dyes:-
•Fading
•Machine wash ability
•Boiling
•Perspiration
•Dry cleaning
•Hot pressing
•Steam pressing
•Salt water
•Gas fume fading (from oil heaters)
•Fastness assessments
•Acid Dyes:-Acid dyes comes in a wide variety of colors, it
is fairly fast to light and to washing. It is named acid dyes
because they work best when applied in an acid bath. It is
mainly used on nylon, silk and wool.
•Basic Dyes:-This type of dye is just fair when it comes

to fastness to light and to washing, however this type can
create a brilliant color. It is mainly used on natural and
acrylic fibers, it is also sometimes used for wool and silk.
This dye is also used to color paper. Acetic acid is usually
added to the dyebath to help in the quick penetration of the
dye onto the fiber.
•Azoic (or Naphthol) Dyes:-This type of dyes are
extremely fast to light, it is commonly used to dye a material
red, orange or maroon. It is mainly used in cotton.
•Vat Dyes:- Vat dyes are an ancient class of dyes, based

on the natural dye, indigo, which is now produced
synthetically. The process 'vat dyeing' refers to dyeing in a
bucket or vat. It can be performed whenever a liquid, even
shade over the entire garment is desired.
•Sulphur Dyes:-This dyes contain sulphur atoms in their

molecules. Sulphur dyes are insoluble in water. This dyes are
achieved by an oxidation treatment with a mild reagent such
as sodium perborate. The fibers most readily coloured with
sulphur dyes are the natural and man-made cellulosic fibers.
•Disperse Dyes:- This dyes is finely ground in the
presence of dispersing agent, its dyeing rate is greatly
influenced by the dispersing agent used during the grinding.
Disperse dyes were developed because other dyes would not
work with acetate it is also used on different manmade fibers,
including acrylic, acetate, and polyester fibers.
•Developed (or Diazo) Dyes:-They are used to treat

certain dyed fabrics to improve their fastness to light and to
washing and also to change fabric's color. The treatment are
used primarily on cotton. Diazotizing is the treatment which
involves the use of chemical called a developer. It is mainly
used on cotton.
•Reactive Dyes:- This dyes react chemically with the fiber
polymers of some fibers to form a covalent bond between the
dye molecule and the fiber molecule. This dyes are coloured on
different manmade and natural cellulosic fiber ,synthetic nylon,
and natural protein fibers.
•Direct Dyes:- This type is one of the easiest to use and

has a wide range of colors, it is not fast to washing, but its
fastness is often improved by more treatment. It is mainly used
on cotton, rayon leather, wool, silk and nylon. It is also used as
pH indicators and as biological stains.
Mordant Dyes:-This type of dye is fairly fast to light and
to washing, it is especially useful for black and navy shades.
The choice of mordant is very important as different mordants
can alter the final color significantly, it is important to know
also that many mordants, particularly those in the hard metal
category can be hazardous to health, that is why caution
should be followed when using it. It is mainly used for wool
and silk.
Mordant is a chemical that is mixed with the dye and the
fiber, the modern mordants are dichromates and chromium
complexes, that is why it is also called chrome dye.
•Synthetic dyes give bright and vivid colours than
natural dyes.
•Any of the organic dyes originally derived from
coal-tar derivatives, but currently synthesized
from benzene and its derivatives.
•A greater range of colours and shades is
available from synthetic dyes than natural dyes.
•The same dye has quite different effects on
different fabrics.
•There are different types of synthetic dyes for
different fiber content.
•Textile Science
second edition; an explanation of fibre properties;
E.P.G. Gohl and L.D.Vilensky;
CBS Publishers and Distributors-1987.
•Technology of Dyeing
Volume Sixth;
Prof. V.A. Shenai;
Sevak Publication, Mumbai-1994.
•Mordern Technology of Textiles : Dyes & Pigments,

National Institute Of Industrial Research, New delhi;
•www.answer.com

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Synthetic dyes are chemically made dye, which

have more shades of colours than natural dyes.

•Basic Dyes:-This type of dye is just fair when it comes

•Vat Dyes:- Vat dyes are an ancient class of dyes, based

•Sulphur Dyes:-This dyes contain sulphur atoms in their

•Developed (or Diazo) Dyes:-They are used to treat

•Direct Dyes:- This type is one of the easiest to use and

•Mordern Technology of Textiles : Dyes & Pigments,

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