"The process of applying color to fiber stock, yarn or
fabric is called dyeing." There may or may not be thorough penetration of
the colorant into the fibers or yarns.
Dyes can be used on vegetable, animal or man made fibers
only if they have affinity to them. Textile dyes include acid dyes, used mainly
for dyeing wool, silk and nylon and direct or substantive dyes, which have a
strong affinity for cellulose fibers. Mordant dyes require the addition of
chemical substances, such as salts to give them an affinity for the material
being dyed. They are applied to cellulose fibers, wool or silk after such
materials have been treated with metal salts. Sulfur dyes, used to dye
cellulose, are inexpensive, but produce colors lacking brilliance. Azoic dyes
are insoluble pigments formed within the fiber by padding, first with a soluble
coupling compound and then with a diazotized base. Vat dyes, insoluble in
water, are converted into soluble colorless compounds by means of alkaline
sodium hydrosulfite. These colorless compounds are absorbed by the cellulose,
which are subsequently oxidized to an insoluble pigment. Such dyes are
colorfast. Disperse dyes are suspensions of finely divided insoluble, organic
pigments used to dye such hydrophobic fibers as polyesters, nylon and cellulose
Reactive dyes combine directly with the fiber, resulting in
excellent colorfastness. The first ranges of reactive dyes for cellulose fibers
were introduced in the mid-1950. Today, a wide variety is available.
Methods of Dyeing:
1) Bale Dyeing: This is a low cost method to dye cotton cloth. The
material is sent without scouring or singeing, through a cold water bath where
the sized warp has affinity for the dye. Imitation chambray and comparable
fabrics are often dyed this way.
2) Batik Dyeing: This is one of the oldest forms
known to man. It originated in Java. Portions of the fabric are coated with wax
so that only un-waxed areas will take on the dye matter. The operation may be
repeated several times and several colors may used for the bizarre effects.
Motifs show a mlange, mottled or streaked effect, imitated in machine
3) Beam Dyeing: In this method the warp is dyed prior to weaving. It
is wound onto a perforated beam and the dye is forced through the perforations
thereby saturating the yarn with color.
4) Burl or speck Dyeing: This is done mostly on woolens or
worsteds, colored specks and blemishes are covered by the use of special
colored links which come in many colors and shades. It is a hand operation.
5) Chain Dyeing: This is used when yarns and cloth
are low in tensile strength. Several cuts or pieces of cloth are tacked
end-to-end and run through in a continuous chain in the dye color. This method
affords high production.
6) Cross Dyeing: This is a very popular method in which varied color effects
are obtained in the one dye bath for a cloth which contains fibers with varying
affinities for the dye used. For example, a blue dyestuff might give nylon 6 a
dark blue shade, nylon 6, 6 a light blue shade, and have no affinity for
polyester area unscathed or white.
7) Jig Dyeing: This is done in a jig, kier, vat, beck or vessel in
an open formation of the goods. The fabric goes from one roller to another
through a deep dye bath until the desired shade is achieved.
8) Piece Dyeing: The dyeing of fabrics in the cut,
bolt or piece form is called piece dyeing. It follows the weaving of the goods
and provides a single color for the material, such as blue serge, a green
9) Random Dyeing: Coloring only certain designated
portions of the yarn. There are three ways of doing this type of coloring:
Skeins may be tightly dyed in two or more places and dyed at
one side of the dye with one color and at the other side with another one.
Color may be printed onto the skeins which are spread out on the blanket fabric
of the printing machine.
Cones or packages of yarn on hollow spindles may be arranged
to form channels through which the yarn, by means of air-operated punch, and
the dyestuff are drawn through these holes by suction. The yarn in the
immediate area of the punch absorbs the dye and the random effects are thereby