Chapter - 3 FIBRE to FIBRE

·      Some fibers are obtained from plants.

·      Wool and silk fibers are obtained from animals.

·      Wool is obtained from the fleece (hair) of sheep or yak.

·      Silk fibers come from cocoons of the silk moth.

WOOL

Wool comes from sheep, goat, yak and some other animals. These wool-yielding animals bear hair on their body. Hair traps a lot of air. Since air is a poor conductor of heat, it keeps these animals warm. Wool is derived from these hairy fibers.

The hairy skin of the sheep has two types of fibers that form its fleece:

(i)            The coarse beard hair,

(ii) The fine soft under-hair close to the skin. The fine hair provides the fibers for making wool. Some breeds of sheep possess only fine under-hair. Their parents are specially chosen to give birth to sheep which have only soft under hair. This process of selecting parents for obtaining special characters in their offspring, such as soft under hair in sheep, is termed ‘selective breeding’.

ANIMALS THAT YIELD WOOL

          Several breeds of sheep are found in different parts of our country. However, the fleece of sheep is not the only source of wool, though wool commonly available in the market is sheep wool. Yak wool is common in Tibet and Ladakh. Angora wool is obtained from angora goats, found in hilly regions such as Jammu and Kashmir. Wool is also obtained from goat hair. The under fur of Kashmiri goat is soft. It is woven into fine shawls called Pashmina shawls. The fur (hair) on the body of camels is also used as wool. Llama and Alpaca, found in South America, also yield wool.

FIBRES TO WOOL

For obtaining wool, sheep are reared. Their hair is cut and processed into wool.  Rearing and breeding of sheep

 Sheep are herbivores and prefer grass and leaves. Apart from grazing sheep, rearers also feed them on a mixture of pulses, corn, jowar, oil cakes (material left after taking out oil from seeds) and minerals. In winter, sheep are kept indoors and fed on leaves, grain and dry fodder. Sheep are reared in many parts of our country for wool. The quality and texture of the fibers obtained from them is also indicated in the table. Certain breeds of sheep have thick coat of hair on their body which yields good quality wool in large quantities. As mentioned earlier, these sheep are “selectively bred� with one parent being a sheep of good breed. Once the reared sheep have developed a thick growth of hair, hair is shaved off for getting wool.

PROCESSING FIBRES INTO WOOL

The wool which is used for knitting sweaters or for weaving shawls is the finished product of a long process, which involves the following steps:

 Step I: The fleece of the sheep along with a thin layer of skin is removed from its body. This process is called shearing. Machines similar to those used by barbers are used to shave off hair. Usually, hairs are removed during the hot weather. This enables sheep to survive without their protective coat of hair. The hair provides woolen fibers. Woolen fibers are then processed to obtain woolen yarn.

Step II: The sheared skin with hair is thoroughly washed in tanks to remove grease, dust and dirt. This is called scouring. Nowadays scouring is done by machines.

Step III: After scouring, sorting is done. The hairy skin is sent to a factory where hair of different textures are separated or sorted.

Step IV: The small fluffy fibers, called burrs, are picked out from the hair. These are the same burrs which sometimes appear on your sweaters. The fibers are scoured again and dried. This is the wool ready to be drawn into fibers.

Step V: The fibers can be dyed in various colors, as the natural fleece of sheep and goats is black, brown or white.

Step VI: Fibers are straightened, combed and rolled into yarn. The longer fibers are made into wool for sweaters and the shorter fibers are spun and woven into woolen cloth.

SILK

 Silk fibers are also animal fibers. Silkworms spin the 'silk fibers'. The rearing of silkworms for obtaining silk is called sericulture.

LIFE HISTORY OF SILK MOTH

The female silk moth lays eggs, from which hatch larvae which are called caterpillars. They grow in size and when the caterpillar is ready to enter the next stage of its life history called pupa, it first weaves a net to hold itself. Then it swings its head from side to side in the form of the figure of eight (8). During these movements of the head, the caterpillar secretes fiber made of a protein which hardens on exposure to air and becomes silk fiber. Soon the caterpillar completely covers itself by silk fibers. This covering is known as cocoon. The further development of the moth continues inside the cocoon. Silk fibers are used for weaving silk cloth. The silk yarn (thread) is obtained from the cocoon of the silk moth. There is a variety of silk moths which look very different from one another and the silk yarn they yield is different in texture (coarse, smooth, shiny, etc.). Thus, tassar silk, mooga silk, kosa silk, etc., are obtained from cocoons spun by different types of moths. The most common silk moth is the mulberry silk moth. The silk fiber from the cocoon of this moth is soft, lustrous and elastic and can be dyed in beautiful colors. Sericulture or culture of silkworms is a very old occupation in India. India produces plenty of silk on a commercial scale.

FROM COCOON TO SILK

For obtaining silk, moths are reared, and their cocoons are collected to get silk threads.

Rearing silkworms: A female silk moth lays hundreds of eggs at a time. The eggs are stored carefully on strips of cloth or paper and sold to silkworm farmers. The farmers keep eggs under hygienic conditions and under suitable conditions of temperature and humidity. The eggs are warmed to a suitable temperature for the larvae to hatch from eggs. This is done when mulberry trees bear a fresh crop of leaves. The larvae, called caterpillars or silkworms, eat day and night and increase enormously in size. The worms are kept in clean bamboo trays along with freshly chopped mulberry leaves. After 25 to 30 days, the caterpillars stop eating and move to a tiny chamber of bamboo in the tray to spin cocoons. Small racks or twigs may be provided in the trays to which cocoons get attached. The caterpillar or silkworm spins the cocoon inside which develops into the silk moth.

Processing silk:

 A pile of cocoons is used for obtaining silk fibers. The cocoons are kept under the sun or boiled or exposed to steam. The silk fibers separate out. The process of taking out threads from the cocoon for use as silk is called reeling the silk. Reeling is done in special machines, which unwind the threads or fibers of silk from the cocoon. Silk fibers are then spun into silk threads, which are woven into silk cloth by weavers.

DISCOVERY OF SILK

The exact time of discovery of silk is perhaps unknown. According to an old Chinese legend, the empress Si-lung-Chi was asked by the emperor Huang-ti to find the cause of the damaged leaves of mulberry trees growing in their garden. The empress found white worms eating up mulberry leaves. She also noticed that they were spinning shiny cocoons around them. Accidentally a cocoon dropped into her cup of tea and a tangle of delicate threads separated from the cocoon. Silk industry began in China and was kept a closely guarded secret for hundreds of years. Later, traders and travelers introduced silk to other countries. The route they travelled is still called the ‘silk route’.

OCCUPATIONAL HAZARD

Wool industry is an important means of livelihood for many people in our country. But sorter’s job is risky as sometimes they get infected by a bacterium, anthrax, which causes a fatal blood disease called sorter’s disease. Such risks faced by workers in any industry are called occupational hazards.