05-02-2013, 02:44 PM
Sericulture
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silkworm and cocoon
Sericulture, or silk farming, is the rearing of silkworms for the production of raw silk. Although there are several commercial species of silkworms, Bombyx mori is the most widely used and intensively studied. According to Confucian texts, the discovery of silk production by B. mori dates to about 2700 BC, although archaeological records point to silk cultivation as early as the Yangshao period (5000 – 3000 BCE).[1] About the first half of the 1st century AD it had reached ancient Khotan,[2] and by AD 140 the practice had been established in India.[3] Later it was introduced to Europe, the Mediterranean and other Asiatic countries. Sericulture has become one of the most important cottage industries in a number of countries like China, Japan, India, Korea, Brazil, Russia, Italy and France. Today, China and India are the two main producers, together manufacturing more than 60% of the world production each year.
Production
Silkworm larvae are fed mulberry leaves, and, after the fourth moult, climb a twig placed near them and spin their silken cocoons. This process is achieved by the worm through a dense fluid secreted from its gland structural glands, resulting in the fibre of the cocoon. The silk is a continuous-filament fiber consisting of fibroin protein, secreted from two salivary glands in the head of each larva, and a gum called sericin, which cements the two filaments together. The sericin is removed by placing the cocoons in hot water, which frees the silk filaments and readies them for reeling. This is known as the degumming process.[4] The immersion in hot water also kills the silkworm pupae.
Single filaments are combined to form thread. This thread is drawn under tension through several guides and wound onto reels. The threads may be plied together to form yarn. After drying the raw silk is packed according to quality.
Where Does Silk Come
The silk based textiles we are used to enjoying in our clothes and bedding are filled with a natural fibre which originates from little domesticated creatures known as silkworms, which are harvested due to their natural production of silk cocoons. While they feed and reproduce, the silk worms create a surrounding environment for themselves which can be unwoven and treated to become the long-stranded fibres which people experience. Let’s explore the silk production process together!
Extracting Raw Silk
The production process of silk can seem deceptively simple but indeed has several steps. In fact, the process of creating silk fibres of the highest quality take a few weeks to complete.
Here is a quick breakdown of the entire process:
First, the new born larvae of the silkworms are kept in a warm and stable environment and given plenty of mulberry leaves, their favourite diet.
The silkworms naturally produce cocoons around themselves to pupate. This process is done through “spinning”: the worm secretes a dense fluid from its gland structural glands, resulting in the fibre of the cocoon.
The cocoons are sorted carefully according to size and quality.
Boiling water with soap is used unravel the silk fibres from the cocoon. This is known as the degumming process.
The outer shell of the cocoon is fed into into the spinning reel, which is still often operated manually
The long fibre thread that are extracted from the cocoon are then cleaned and stripped from any deficiencies.
The silk fibres are implemented into products such as bedding and clothes
Silk Fibres Can Be Enhanced
Did you know that silk is hypo-allergenic purely because of natural properties? However, when it is processed into usable objects that we touch in daily life, it’s also important to make sure that it is not left under the influence of chemicals or other allergens. The process through which a silk duvet is made should be as healthy and clean as the much as the silk production process. What’s more, silk fibres can be made stronger and better through diligent research. Since the silk sleeping environment temperature regulated and moisture absorbent, it’s extremely hard for bacteria to develop. However, most silk fibres cannot be washed safely without the risk of damaging the core structure of the duvet or comforter. This is frustrating, as over the years naturally people might want to clean their duvet. A great example of silk enhancement in action is the application of nanotechnology to silk fibres in order to add to their natural longevity and strength, and therefore become able to withstand hotter washing temperatures.