Silk is a natural protein fiber composed mainly of fibroin and is produced by certain insect larvae to form cocoons. Silk has a high emissivity for infrared light, making it feel cool to the touch. Even though silk has a small percentage of the global textile market, it is a multibillion-dollar trade. The unit price for raw silk is roughly twenty times that of raw cotton.
Pretreatment of silk primarily consists of degumming process which consists of removing the sericin, or silk gum, from silk. Removing the gum improves the sheen, color, hand, and texture of the silk. Because the gum can serve as a protective layer, it is typically left on the silk until it is ready to dye.
Silk is dyed using various dyes such as acid dyes, metal-complex, reactive dyes etc. Silk offers a wide colouration possibility covering almost the entire spectrum of colours and hues due to its ready acceptability for a large range of dyestuffs. The exceptional capacity to absorb moisture from the air, the comparatively simple and orderly arrangement of fibroin molecular structure, and the abundance of hydrogen bonds and electrostatic bonds render silk fibre an ideally suited substrate with a very good dye affinity.