Wednesday, August 21, 2019



The fibroin present in the silk fibre is covered by thin layer of sericin. This sericin present in the silk fibres greatly affects the handle, sheen and texture of the finished goods,. It gets necessary to remove the sericin from the silk fibres. The silk gets more soft, lustrous after removal of sericin. The improved texture is also resulted after sericin removal. This serricin is also known as silk gum.

Thus, we can say that  the main objective of the degumming process is to get improved lustre, softness, and texture. “The process of removing the sericin or silk gum from silk fibre is called degumming”.

As mentioned above, the silk gum( sericin) in the silk fibres acts as a protecting cover in it. This layer of sericin is kept unremoved till fabric manufacturing ( weaving) if the fabric is woven with undyed silk. This silk gum is removed during fabric dyeing. If we weave the fabric with yarn dyed silk, it gets necessary to remove the gum in yarn form.

During degumming proces proces, the yarn or fabric is treated with an alkaline ( sodium carbonate) and surfacing agent( sodium lauryl sulphate) .The required chemicals are dissolved in normal water. Some amount of hot water is added to it for proper dissolution of chemicals. This solution is boiled initially, the the temperature is reduced. It remains still hot. Now the yarn or fabric is teated with this solution for 30 minutes. The silk is washed with hot water. Then it is neutralized with citric acid or any other suitable neutralizing agent ( acid).

There almost 15℅ to 25 % weight loss occurs after complete removal of sericin during degumming of silk.


We know that a huge weight loss occurs during the degumming of silk. This weight loss is recovered again by treating the processed silk with weighting agent. " The process of recovery of weight loss during degumming  by using any external weighting agent is called weighting of silk". In this process the processed silk is treated with any suitable silicate solution. The properties of silk like feel, softness, and lustre also get changed up to some extent. Extra dose of weighting agent can be harmful to the silk fabrics.

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