Silk

Silk is a natural protein fiber made from unraveling the cocoons of silkworms. The silkworm creates a cocoon using its pair of salivary glands called sericteries, which creates the protein fibroin. Fibroin is a clear, proteinaceous fluid that comes out of the mouthpart of the silkworm larva like a spinneret. The fibroin is a continuous filament that will determine the length and width of the thread. During this process a second pair of glands secretes a binding protein called sericin. With these two proteins the silkworm rotates its body in a figure-8 movement about 300,000 times, this produces about a mile of thread. The thread is then unraveled from the cocoon by treating it with hot air, steam or boiling water and then reeling the filaments with a slight twist to create a strand. Usually about 2500 silkworms are required to produce a pound of raw silk.

 

The process of creating the silk yarn is called throwing. Throwing prevents the threads from splitting. These can be created into 4 different types of silk, crepe, tram, thrown singles and organzine. To start crepe is made by twisting individual threads, doubling two or more of them together and then twisting them again, these are used to weave crinkly fabrics or as a single thread for sheer fabrics. Tram is made by twisting two or more threads in only one direction, these are used for the weft or filling threads. Thrown singles are single threads twisted in one direction. Finally organzine is made by giving the thread a preliminary twist in one direction and then twisting two threads together in the opposite direction, this is used for the warp threads of materials.

 

Silks best properties include it being the strongest natural fiber, its drape and luster, its hydrophilic, it has electrical conductivity, thermal retention, its flame retardant, and it does not pill when worn.

silk