Degumming process and recipe of silk fabric. Silk is a type of natural animal fiber. The silk fiber is made from Silkworm. It is available in filament form. Raw silk fibers contain natural waste called silk gum or sericin. The amount of this sericin is about 20% of the weight of the entire silk. In addition, there is some amount of wax and Natural Color Pigment as waste. Sericin and other wastes in silk can be removed through the scouring process. This process is called Degumming Process.
Degumming agent of silk:
(i) Soap
(ii) Sodium Carbonate and Bicarbonate
(iii) Synthetic detergents etc. are used.
Recipe:
Soap – 0.50 to 0.75% (percentage of silk weight)
Silk and water = 1:14 (ratio of silk and water)
Or water = 14 times the weight of silk
Temperature = 95 ° C
Time = 30 minutes to 2 hours
pH = 10
Silk degumming method:
The main purpose of silk degumming is to completely remove sericin from silk. The chemical composition of sericin is similar to that of amino acids. It has hydrolyzed properties like fats and oils.
First, 14 times the weight of silk is taken in a pot of water. Then 0.5 to 0.75% soap is added to the container. After increasing the temperature to 50 ° C, the silk is added. After further raising the temperature to 95 ° C, the product has to be stirred well and boiled for 30 minutes to 2 hours (as required). However, it should be noted that the pH should be in the middle of 10. Silk is to be degummed in very smooth containers. Finally, it is washed with hot water and cold water and dried. As a result, 97.5% of boiled gum or sericin is removed. Synthetic detergents are currently used instead of soaps or mild alkalis. It is less likely to damage the silk.
Degumming process and recipe of silk fabric. In many cases, only 2.5% to 4% sericin is removed from the silk to get un-bleached silk. I.e. mild scouring or degumming is done. This type of silk is called Ecru Silk. Processing the soap solution at room temperature for 40 to 60 minutes removes 2.5% to 4% of its sericin and Ecru Silk is obtained. However, it is not suitable for bleaching.
The silk that is obtained by removing 6% to 15% sericin from silk is called souple silk. Usually, when boiled in soap solution for 1 to 2 hours at a temperature of 30 to 35 ° C, 7 to 15% sericin is removed and souple silk is obtained. Souple silk is used as yarn and for medium and heavy dyeing shades. However, it is not suitable for light shade.
Caution in silk degumming:
The following precautions should be taken while silk degumming.
1. Liquor should not be stirred in pairs.
2. Excessive boiling can damage the fiber.
3. Excessive alkali can damage the fiber.
4. Synthetic detergents should be used instead of soap or mild alkali.
5. Fiber can be damaged if the inner surface of the machinery is not very smooth.
