SILK FIBER

Silk is a protein fiber and only one natural continuous filament made by the silkworm, produced by caterpillars belonging to the genus Bombyx. The most beautiful among all textile fibers is silk, which is claimed as the queen of textiles. It comes from the cocoon of the silk worm and requires a great deal of handling and processing, which makes it one of the most expensive fibers also. Archeological ecidence indicates that silk production may have begun as early as 5000BC-that's more than seven thousand years ago. Silk and sericulture (the culturing of silk) probably began in China more than 4,000 years ago. The silk filament is a continuous thread of great strength measuring from 500-2000 meters in length. Single filaments are too thin for utilization. For production purposes, several filaments are combined with a slight twist into one strand. This process is known as "silk reeling or filature". Major silk producing countries are: China, India, Thailand, North America, United kingdom, Japan, Italy, France, former USSR, Brazil, Turkey and Korea. 

There are about 50,000 silkworms are required to produce 1000 kg of cocoons, from which 120 kg of raw silk is collected.

Silk consists of two type of proteins; sericin and fibroin, fibroin being the structural center of the silk, and sericin being the gum coating the parallel two filament and allowing them to stick to each other. The surface of the raw silk strand is uneven and irregular due to the coating of sericin, which gives raw silk a coarse handle. Fibroin is made up of sixtheen different amino acids. Like wool, it is made from long-chain protein molecules. Each of the two individual fibroin filaments is constructed from fibrillar bundles (tiny fibers) which themselves are made from micro fibrils. The micro fibrils are built from the protein chains. Every fibril and micro-fibril is arranged linearly according to the length of fiber.