Structure of Wool Fiber

 Microscopic Structure: Wool fibers are made up of a complex protein called keratin,
which gives them their unique properties. Each wool fiber has three main layers:
o Cuticle: The outermost layer composed of overlapping scales, which protect
the fiber and contribute to its texture.
o Cortex: The middle layer, making up about 90% of the fiber. It consists of two
cell types, orthocortex and paracortex, which give wool its natural crimp or
waviness.
o Medulla: The innermost layer, a hollow core that may be present in coarser
wool fibers, contributing to insulation.
 Crimp: The natural waviness of wool fibers, which provides elasticity and bulk. This
crimp allows wool fibers to trap air, providing warmth.
Production of wool
1. Shearing

 Wool is harvested from sheep through the process of shearing, typically done once or twice
a year. The fleece is removed in a single piece, and the quality of the wool depends on the
breed of sheep and the care taken during the shearing process.

2. Sorting and Grading

 After shearing, the fleece is sorted and graded based on the length, fineness, and cleanliness
of the fibers. Wool from different parts of the sheep’s body varies in quality, so sorting
ensures that only the best fibers are used for fine yarns, while coarser wool is reserved for
other products like carpets.

3. Scouring

 Wool fibers contain natural oils, grease (lanolin), dirt, and other impurities that must be
removed. Scouring is the process of washing the wool in hot water with detergents to
remove these contaminants. Clean wool is essential for smooth spinning and high-quality
yarn production.

4. Carding

 Carding involves disentangling and aligning the wool fibres into a parallel form to create a
continuous sheet or web. This is done using large rollers with fine wire teeth. Carding also
removes any remaining impurities and begins the process of forming the wool into a soft,
loose strand known as a sliver.

5. Combing (Optional for Worsted Wool)

 For producing worsted yarn, the wool undergoes an additional step called combing. This
process removes short fibers and further aligns the remaining fibres in a parallel direction,
producing a smoother, finer yarn. Combed wool is used to make worsted fabrics, which are
smooth, durable, and high-quality.

6. Drawing

 During drawing, several slivers are combined and drawn out into a thinner, more uniform
strand. This process ensures that the fibres are aligned and evenly distributed, improving the
consistency and strength of the final yarn.

7. Roving

 In this stage, the drawn-out wool fibres are slightly twisted to form a loose, thicker strand
called "roving." The roving prepares the fibres for spinning by holding them together, making
it easier to handle during the spinning process.

8. Spinning

 Woolen Spinning: In woollen spinning, the fibres are less aligned, and the yarn produced is
bulkier, with more air pockets, making it soft and warm. Woolen yarns are used for items like
sweaters, scarves, and blankets.
  Worsted Spinning: In worsted spinning, the fibers are tightly aligned and twisted, creating a
smoother, finer, and stronger yarn. Worsted yarn is used for high-quality fabrics such as suits,
dresses, and fine knitwear.

 The spinning process involves feeding the roving into a spinning wheel or modern spinning
machine, which draws out the fibers further and twists them into a continuous thread of
yarn. The level of twist determines the yarn's strength and texture.

Properties of Wool Fiber

 Physical Properties:
o Crimp: Wool's natural crimp gives it elasticity, resilience, and the ability to
trap air, providing insulation.
o Strength: Wool has moderate strength but is weaker when wet.
o Elasticity: High elasticity allows wool to stretch and recover shape without
wrinkling.
o Absorbency: Wool is hygroscopic, meaning it can absorb moisture without
feeling wet, making it comfortable to wear.
o Thermal Insulation: Wool provides excellent thermal insulation due to the
trapped air within the fibers.
 Chemical Properties:
o Reaction to Alkalis: Wool is sensitive to alkalis; mild alkalis can damage the
fiber.
o Reaction to Acids: Wool is relatively resistant to acids, which can be used to
clean it.
o Flame Resistance: Wool is naturally flame-resistant, charring rather than
burning.

Types of Wool Fiber

 Merino Wool: Considered the finest and softest wool, it comes from Merino sheep. It
has a high crimp and is used for high-quality apparel.
 Cashmere: Obtained from Cashmere goats, it is extremely soft, fine, and luxurious.
Cashmere is lightweight and provides excellent insulation.
 Mohair: Comes from the Angora goat, known for its silky texture and high luster. It is
durable, resilient, and often used in knitwear and home textiles.
 Angora: Produced from Angora rabbits, it is extremely soft and has a fluffy
appearance. Used for luxury garments and accessories.
 Lambswool: The first shearing of a sheep, typically softer and finer than wool from
adult sheep.
 Shetland Wool: Comes from Shetland sheep, known for its fine, soft, and warm
properties, often used in knitwear.
 Alpaca Wool: From the alpaca animal, it is soft, lightweight, and hypoallergenic. It is
used for sweaters, scarves, and blankets.