Synthetic Fibres and Plastics

Wool

Wool is the textile fibre and animal fibre. We get wool from sheep and other animals. For instance, cashmere and mohair from goats, qiviut from muskoxen, hide and fur clothing from bison, angora from rabbits, and other types of wool from camelids. Wool consists of protein together with a small number of lipids.

It is chemically a bit distinct from the more dominant textile, cotton, which is mainly cellulose. Wool fibre has a highly organized structure. Its main histological components include the cuticle, cortex and medulla. Wool fibre is a natural fibre. Characteristics of wool are diameter, crimps and length are important parameters of the wool trait. It is an important indicator of the spinning efficiency of the wool.

Wool

                                                                                                     Wool

Introduction to Wool

Wool is produced by follicles. Follicles are small cells present in the skin. These follicles are present in the upper layer of the skin called the epidermis and push down into the second skin layer called the dermis as the wool fibres grow. Follicles are either primary follicles of secondary follicles. Primary follicles produce three types of fibre i.e., kemp, medullated fibres, and true wool fibres. Secondary follicles produce only true wool fibres. Medullated fibres share a bit identical characteristic to hair and are long. Medullated fibre lacks in crimp and has elasticity.

Animals Yielding Wool

We get wool fibres from sheep, goat, angora rabbits, goats, alpaca and even camels.

Sheep – Most sheep have two types of hair on their body from which the wool is obtained. The outer coarse hair is Kemp. The fine, soft undercoat close to the skin is the true wool from which we get wool fibre

Cashmere goat -The fine soft fibre from the undercoat of the cashmere goat is cashmere. The outer coat hair fibres are coarse and high-quality cashmere is obtained by dehairing or combing. Cashmere goats are found in mountain regions of China.

Yak -Yaks are found in Tibet and Ladakh region. Their coats have outer long coat hair and an undercoat of soft and silky wool. The colour of coats and an undercoat ranges from brown to black.

Camel -Camel fleece consists of a soft, fine undercoat and an overcoat of long coarse hair. It grows up to 15 inches long. Camel wool is a healthy natural product. Camel wool has excellent thermal insulation property.

Angora rabbit -Soft white fibre is known as goraw wool is obtained from the angora rabbit. Stiff, long, guard hair growing through the soft coat must be removed before the fur from angora rabbits is combed out. The soft white fur is then spun into yarn that is in use to make sweaters.

Step by Step Extraction of Wool from Sheep

The steps in the production of wool are as follows:

1)Sheep fur collection – This is the first step of the process of extracting wool from sheep. The fur quality is identified first and then it is shaved. Only skin fur is collected not the beard hairs. After this, it proceeds to the next step.

2)Shearing – Shearing is the process of removal of the woollen coat or fleece from the animal. This is done without harming the animal by using shearing equipment such as scissors, hand blades and electric shears. This process is usually done during the hot season. This allows sheep to grow back hair by the time winter arrives. The amount of wool produced by a sheep varies from 1 to 3 kg.

3)Scouring – Once the fur is collected it should be scoured properly. Wool is directly taken from the sheep i.e., raw or grease wool. The raw sheared wool is then properly washed with detergent and alkali in tanks. It is done to remove grease, dust and dirt. This process is scouring. Nowadays scouring is done by machines.

4)Sorting and grading – This is the process of making wool. After scouring the inferior wool is removed. It is done to separate low-quality hair and high-quality hair. The lower quality of hair is rougher than the high-quality one. This process is called sorting. Sorting of wool is according to the length, colour and texture of fibres is grading.

Carding – Before wool is in use for making fabric it is disentangled and properly cleaned. The intermixed fibres are efficiently separated to form continuous fibres. This process is carding. The fibres are passed through a series of metal teeth to straighten the fibres and make in fine.

6)Making yarn – After the process of carding wool is twisted into a rope called silver. The silver is then twisted and stretched into a thin yarn. The spinning of woollen yarns is done properly on a mule spinning machine.

7)Dyeing – In this process wool is different colours are added to the fibres before converting them into a fabric. These colours are added using different dyes that set well with the woollen fibres.

8)Straightening and finishing – The dyed fibre is straightened first. In the end, woollen yarn is woven or knitted into fabric. It is then in use to make final products such as clothes, table cloths, bags etc.

Properties and Quality of Wool

1)DurabilityWool is a hard fibre that remains and retains its fine appearance for a long time.

2)Absorption of moisture – As a fabric wool draws moisture from the body. Wool absorbs moisture inside its fibres. Heat is generated as the moisture is absorbed. This is the reason why the garment stays warm without feeling wet.

3)Resistance to dirt – Wool fibres have an outer layer of scales that reduce the ability to penetrate dirt and dust from the fibre.

4)Resistance to fire – One of the properties of wool is that it does not burn easily. When subjected to flames, it will smoulder instead.

5)Repel nature – Though wool absorbs moisture the scales on the outer layer of each fibre repel liquids.

6)Insulating nature – Small gaps are present between the fibres. These gaps are filled with bubbles of air, that heat up as the moisture in the centre of the fibre heats up, making wool an insulator.

FAQs on Wool

Question 1: Is wool a natural Fibre?

Answer: Wool is a stock of natural fibre. Every year sheep grows a new fleece after shearing. New fleece can be shorn off the following year again. Natural fabrics like fur are biodegradable. Wool is a naturally occurring protein that is similar to that found in human hair.

Question 2: What are the characteristics of good wool?

Answer: Wool is the most durable fibre because it has a natural crimp. This natural crimp helps it to maintain its shape. Wrinkles vanish when the robe or cloth is steamed. Good wool is very soft and hardy whereas weak wool is rough.

Question 3: Where is wool made?

Answer: Wool is made from follicles that are found in the skin, which are tiny cells. These follicles are located in the top layer of the skin called the epidermis. It is pressed down into the second layer of skin i.e., the dermis as the fibres of the wool expands.

Question 4: Why is the scouring process done in the extraction of wool from sheep?

Answer: Scouring is the process where the tangled fur is soaked in big tanks to clean it. This is the first chemical step of extraction of wool where skin grease, dust, lumps, dirt, etc are removed from the fur.

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