SILK AND COMPOSITION

INTRODUCTION:-

Silk is a Natural fiber, as it is a Protein fiber therefore it is composed of Amino acids arranged in Polypeptide chains. It has a unique combination of properties not possessed by any other fiber.

 “Dry” tactile hand. Natural luster.  Good moisture absorption. High strength.

SILK GENERAL PROPERTIES:-

Elongation at breaking Standard Wet 20% 30%Absorbency 11% Thermal Property Does not MeltSelf Ironing Temperature 300 ْ F 149 ْ C Sunlight Resistance PoorSolubility 70% in Sulfuric acid at 30 ْCDensity 1.25%Elastic Recovery 99 %

CULTIVATION:-

The cultivation of Silk is called Sericulture. Over 30 countries produce silk, and the major ones are China (54%), India (14%) and Japan (11%).Silk moths lay eggs on specially prepared paper. The eggs hatch and the caterpillars (silkworms) are fed fresh mulberry leaves. After about 35 days and 4 molting, the caterpillars are 10,000 times heavier than when hatched, and are ready to begin spinning a Cocoon. A straw frame is placed over the tray of caterpillars, and each caterpillar begins spinning a cocoon by moving its head. Two glands produce liquid silk and force it through openings in the head called Spinnerets.
Liquid silk is coated in Sericin, a water-soluble protective gum, and solidifies on contact with the air. Within 2-3 days, the caterpillar spins about 1 mile of filament and is completely encased in a cocoon. Most caterpillars are then killed by heat and some are allowed to metamorphose into moths to breed the next generation of caterpillars.