How Do We Get Silk From Silkworm

Silk, renowned for its lustrous beauty and soft texture, is a natural protein fiber produced by certain insect larvae. The most well-known source of commercial silk is the silkworm, specifically the larva of the Bombyx mori moth. This process, known as sericulture, involves meticulous care and several stages. This article will explore how we get silk from silkworms, detailing each step from the hatching of eggs to the weaving of fabric.

1. Silkworm Rearing

The first phase of silk production involves the careful rearing of silkworms. Here’s a closer look:

• Egg Incubation: Sericulture begins with silkworm eggs, which are carefully incubated at a specific temperature and humidity to ensure successful hatching. These eggs, often the size of poppy seeds, are kept in controlled environments that mimic springtime conditions.
• Larval Feeding: Once hatched, the tiny silkworms are voracious eaters. Their diet consists exclusively of mulberry leaves. This is a crucial aspect of sericulture, requiring a consistent and plentiful supply of fresh leaves. The silkworms are kept on trays or frames and are provided with fresh leaves multiple times a day as they grow rapidly.
• Growth Stages (Instars): Silkworms go through several growth phases, called instars, each marked by a shedding of their skin. During each stage, they consume large amounts of mulberry leaves and increase in size. These stages typically last for around 25-35 days.

2. Cocoon Spinning

Once silkworms reach their final instar, they begin the remarkable process of cocoon spinning.

• Preparation: Silkworms stop eating and begin to look for a suitable place to spin their cocoons. Farmers often provide small frames or compartments to aid in this process.
• Silk Production: The silkworm’s body contains two glands that secrete a liquid protein called fibroin. This liquid is forced out through the spinneret in its head and hardens on contact with the air. As it spins, the silkworm moves its head in a figure-eight motion, laying down layers of this continuous silk filament.
• Cocoon Formation: It takes about 2-3 days for a silkworm to complete its cocoon. The finished cocoon is made of a single continuous silk strand that can be up to a mile long if unwound.

3. Silk Harvesting

After the cocoons are spun, they are harvested to extract the silk.

• Cocoon Selection: The cocoons are collected and sorted based on their quality and suitability for silk production.
• Stifling: To prevent the silkworm from emerging as a moth and breaking the continuous silk filament, the cocoons are subjected to a stifling process. This is usually done by steaming or drying them. This process kills the pupa inside.
• Sorting and Grading: After stifling, the cocoons are sorted based on color, size, and the overall quality, which impacts the final silk.

4. Silk Reeling

The next critical stage is the unwinding of silk filaments from the cocoons.

• Cocoon Soaking: Cocoons are soaked in hot water to soften the sericin, a gummy protein that holds the silk filaments together.
• Filament Unwinding: The softened sericin allows multiple filaments from several cocoons to be unwound together, typically using mechanized reels. This unwound silk is known as raw silk. The process requires careful attention to prevent breakage and maintain the continuity of the filaments.
• Reeling Process: This stage usually takes place in a factory using specialized machines that draw the silk from several cocoons simultaneously.

5. Processing and Spinning

The raw silk undergoes further processing before becoming fabric.

• Throwing: This involves twisting several raw silk filaments together to create a stronger, more durable yarn. This process is called throwing and the end result is known as ‘thrown’ silk.
• Washing and Dyeing: The raw silk, now in yarn form, is thoroughly washed to remove any remaining sericin. It is then ready for dyeing, where it is given color.
• Spinning (if necessary): If needed, the silk yarns are further spun to create specific types of threads, or can be further processed into noil yarns, using short staple fibers left over from the reeling process.

6. Weaving and Fabric Production

The processed silk yarn is then ready for weaving.

Weaving: The yarns are woven on looms to create silk fabrics. The weaving pattern can vary, resulting in different fabric types like charmeuse, crepe de chine, or chiffon.

Finishing: The finished fabric undergoes various finishing processes that may include further washing, softening, and treatments to enhance its luster, texture, or drape.

Conclusion

The process of obtaining silk from silkworms is a complex and time-honored tradition that requires meticulous care and attention to detail. From the incubation of silkworm eggs to the weaving of finished fabric, each stage is crucial to the production of the luxurious material that has been prized for centuries. The journey of silk, though labor-intensive, reveals the fascinating interplay between nature and human craftsmanship.