process for dying the fabric and Type of dyes.

1. By:
Presented by : Ms.K.Kathiroli
Asst Prof
Dept of fashion technology and costume designing
Bon secours college for women – Thanjavur
.

2.  * Dyeing is the process of adding color to the
textile products like fibers, yarn and fabrics.
 * The temperature and time controlling are main
key factors in dyeing.
 * A dye is a color substance that has a affinity to
substrate to which is being applied.
 * Both dyes and pigments appear to be colored
because they absorb some wavelength of light
more than others.

3.  Dyeing is the application of dyes or pigments
on textile materials such as fibers, yarns, and
fabrics with the goal of achieving color with
desired color fastness. Dyeing is normally done
in a special solution containing dyes and
particular chemical material. Dye molecules are
fixed to the fiber by absorption, diffusion, or
bonding with temperature and time being key
controlling factors. The bond between dye
molecule and fiber may be strong or weak,
depending on the dye used.

4.  1.Acid
 2.Basic
 3.Disperse
 4.Reactive
 5.Sulphur
 6.Azoic
 7.Direct
 8.Vat
 9. Modrant
 10.Solvent

5.  *Natural dyes
 *Synthetic dyes

7.  * Majority of the natural dyes are from plant
sources – bark, berries, roots, leaves, wood and
fungi.
 * Throughout history, people have dyed their
textile using common and locally availabe
materials.
 * The discovery of man-made synthetic dyes late in
19th century ended large –scale market for natural
dyes.

8.  * The first human – made organic dye, mauveine,
was discovery serendipity by William Henry
Perkin in 1856.
 * Synthetic dyes quickly replaced the traditional
natural dyes.
 * The cost less , they offered a vast range of new
colors , and they imparted better properties to the
dyes materials.

10.  Vat dyes are a class of dyes that are classified
as such because of the method by which they
are applied.
 Vat dyeing is a process that refers to dyeing
that takes place in a bucket or vat. Almost any
dye, including fiber-reactive dyes, direct dyes,
and acid dyes, can be used in a vat dye.
 Cotton, wool, leather and other fibers can be
all dyed with vat dyes. The original vat dye is
indigo, once obtained from plants but now
produced synthetically.

11.  In a reactive dye, a chromophore (an atom or group
whose presence is responsible for the color of a
compound) contains a substituent that reacts with the
substrate.
 Reactive dyes have good fastness properties owing to
the covalent bonding that occurs during dyeing.
 Reactive dyes are most commonly used in dyeing of
cellulose like cotton or flax, but also wool is dyeable
with reactive dyes. Reactive dyeing is the most
important method for the coloration of cellulosic fibers.
 Reactive dyes can also be applied on wool and nylon;
in the latter case they are applied under weakly acidic
conditions.

12.  * In contrast to direct dyes, wool and leather
goods are dyed by the process of ion exchange,
exploiting the cationic nature of proteins near
neutral PH. The development of substantive
dyes helped make mordant dyes obsolete.
* A substantive dye or direct dye is a dye that
adheres to its substrate, typically a textile, by non-
ionic forces.

13.  Azoic dyes are organic compounds bearing the
functional group R−N=N−R′, in which R and R′
are usually aryl. They are a commercially
important family of azoic compounds, i.e.
compounds containing the linkage C-N=N-C.
 Azoic dyes are widely used to treat textiles,
leather articles, and some foods. Chemically
related to azoic dyes are azoicpigments, which
are insoluble in water and other solvents

14.  Sulpur dyes are the most commonly used dyes
manufactured for cotton in terms of volume.
 They are inexpensive, generally have good
wash-fastness, and are easy to apply.
 Sulfur dyes are predominantly black, brown,
and dark blue.
 Red sulfur dyes are unknown, although a pink
or lighter scarlet color is available.

15.  Acid dyes are usually sodium salts of sulphonic
acids and a few of them are sodium salts of
carboxylic group.
 These dyes are mainly used for protein and
polyamide fibers.
 Acid dyes posses direct affinity for wool, silk,
nylon, regenerated and protein fibres.
 An acid dye is a dye that is typically applied to a
textile at low PH . They are mainly used to dye
wool, not cotton fabrics.
 Some acid dyes are used as food colorants.

16.  These are soluble in water with little addotion
of acetic acid. Basic dyes produce most brilliant
shades.
 they have direct affinity for wool and silk but
not for cotton.