Dyeing

2. STOCK/TOP Dyeing
• Stock dyeing refers to the dyeing of fibers, or stock, before it is spun
into yarn. It is done by putting loose, un-spun fibers into large vats
containing the dye bath, which is less than heated to proper
temperature. From 500 to 3000 pounds (227 to 1364 kgs.) of fiber
are dyed at one time, and the average is about 1000 pounds (454
kgs.)
•
• Top dyeing is also the dyeing of fiber before it is spun into yarn and
serves the same purpose as stock dyeing that is to produce soft,
heather like color effects. The term top refers to fibers of wool from
which shorter fibers have been removed. Top is thus the select long
fibers that are used to spin worsted yarn. The top in the form of
silver is dyed and then blended with other color of dyed top to
produce desired blended heather shades.

4. Yarn Dyeing
• Yarn dyeing is used to create interesting checks, stripes, and plaids with
different-colored yarns in the weaving process. In yarn dyeing, dyestuff
penetrates the fibers in the core of the yarn.
• Some methods of yarn dyeing are stock, package, and skein dyeing. Stock
dyeing dyes fiber using perforated tubes. In package dyeing, spools of yarn
are stacked on perforated rods in a rack and immersed in a tank where dye
is then forced outward from the rods under pressure.
• The dye is then pressured back through the packages toward the center to
fully penetrate the entire yarn. Most carded and combed cotton used for
knitted outerwear is package-dyed. In skein dyeing, the yarn is
loosely coiled on a reel and then dyed.
• The coils, or skeins, are hung over a rung and immersed in a dyebath
(Corbman, 1975). The skein-dyed yarn is used for bulky acrylic and wool
yarns. Typical capacity for package dyeing equipment is 1,210 pounds (550
kg) and for the skein, dyeing equipment is 220 pounds (100 kg).

5. Skein Dyeing
• Skein dying is a way of dyeing yarn through
dipping skeins or loosely wound hands of
yarns into dye vats. Yarns used for knitting are
typically processed this way.
• Skein dyeing is one of the oldest and
expensive methods of coloring yarn, but it
remains significant for it can color small
portions of yarn.

6. Package Dyeing
• Package dyeing is another way to dye yarn. It
takes place while a yarn is wound on a small
spool or tube, which is referred to as the
package. Several packages of yarn can fit into
a dyeing machine at once, which makes the
process less expensive. However, package
dyeing may result to less soft yarns.

8. Piece Dyeing
• The most dyed fabric is piece-dyed since this method gives
the manufacturer maximum inventory flexibility to meet color demands
as fashion changes. In terms of overall volume, the largest amount of
dyeing is performed using beck and jig equipment (Figure 11). Beck dyeing
is a versatile, continuous process used to dye long yards of fabric.
About 1,980 pounds (900 kg) of fabric can be dyed on beck equipment at a
time.
• The fabric is passed in rope form through the dyebath. The rope
moves over a rail onto a reel which immerses it into the dye and then
draws the fabric up and forwards to the front of the machine. This process
is repeated as long as necessary to dye the material uniformly to the
desired color intensity.
• Jig dyeing uses the same procedure as beck dyeing, however, the fabric is
held on rollers at full width rather than in rope form as it is passed through
the dyebath (Corbman, 1975). This reduces fabric tendency to crack or
crease. Jig dyeing equipment can handle 550 pounds
(250 kg) of fabric.

9. Piece Dyeing
• Dyeing constructed fabrics is called piece dyeing.
The textile manufacturer can dye the whole fabric
in batches according to the fashion demands of
the time thus avoiding wastage and loss. The
great bulk of dyed fabric on the market is dyed in
the piece. There are several common methods of
piece dyeing. Specific names such as union, cross,
tone-on-tone, and reserve dyeing are given to
piece dyeing of fabrics containing fibers that
exhibit different dyeing characteristics.

10. Union Dyeing
• A fabric containing fibers that accept dyes from
different classes are dyed by this method, with a
result that the fabric is dyed in a solid colour.
The fabrics can be either blends of two fibers,
such as cotton and polyester – or mixtures in
which the warp yarns are made of one type and
filling of another. The dyeing process includes one
bath or two bath methods. By using the blend in
various ratios or by randomly using different
yarns in weaving sequence good designs can be
obtained.

11. Cross Dyeing
• In cross dyeing, a multicolored fabric is obtained.
Fabric containing two or more fibers types is
purposely dyed so that each fiber type or variant
accepts a different type of dye and becomes a
different colour. Fabrics may be composed of
– Fibers from different generic group,
– Natural and manufactured fibers, or
– Manufactured fibers from the same generic group
when one fiber has been modified to accept dyes
from a different dye class. The end product depends
on the fiber arrangement in the fabric.

12. Garment dyeing
Dye when applied to finished products such as
apparels and garments, it is called
garment dyeing. This helps the dyer to meet the
demands of fashion colours on time and does
not require to stock huge amounts of
dyed fabrics.

13. Piece Dyed vs Yarn Dyed fabric?
Fabrics those have stripes and checks patterns are normally weaved
using dyed yarns i.e. yarn dyed fabric. (Though check and stripe
patterns can be made by printing). Secondly, a multi color woven
designs in fabric mostly yarn dyed.
Fabrics with solid or single color are mostly piece dyed. Color fastness
of piece dyed fabric is less than yarn dyed fabrics.
Color fastness is good in yarn dyed fabrics. This means that color of the
fabric does not fade away easily. You would not get color bleeding in
yarn dyed fabrics.
In price point, normally yarn dyed fabric are costlier than a piece dyed
fabric

15. Garment Dyeing
• The process of dyeing fully made apparel product
like t-shirts , pants , trousers , shirts , jackets,
tops, pullovers , dresses and bottoms is called
garments dyeing. In Conventional method ,
Garments are made with pre-dyed fabrics and
then cutting and sewing. But now grey fabrics are
dyed in required color after manufacturing. It has
become popular in recent days due to cost saving
and fashion trends. Also it is capable to react
much closer to actual market demand if the
apparel is post dyed which reduces lead time and
increases forecasting accuracy.

16. Advantages of garments dyeing
• Lower cost needed
• Less time needed
• Less shade variations occurs
• Flexible lot size
• Old garments can be redyed
• Lower initial investment
• Lower liquor ratio
• Desizing , Scouring , Bleaching can be done in same machine
• Capable to react with fast changing market trends
• Fancy effects can be obtained
• Lower inventory
• Comparatively lower rejection rate

17. Disadvantages of garments dyeing
• High cost of processing
• More material handling
• Special care for selection of interlining
• Higher seconds rate in production
• Labor intensive process
• Requries full checking of all pieces