Silk degumming is the process of removing sericin, the gummy protein that coats the fibroin core of raw silk fibers. This step is crucial for achieving the soft, lustrous texture characteristic of finished silk fabric.
The most common and widely used method for degumming silk involves a chemical treatment combined with heat.
The Standard Silk Degumming Process
Based on common practices, including the method referenced, the typical process for degumming silk fibers or cocoons is as follows:
- Preparation: Raw silk fibers or cocoons are prepared for treatment.
- Chemical Treatment: The silk material is immersed in a heated chemical solution.
- According to research, the most common method utilizes 0.02 M sodium carbonate (Na2CO3) buffer [7].
- Heating: The solution is brought to a boil. Boiling helps to dissolve the sericin efficiently.
- Duration: The silk is boiled in the solution for a specific period.
- The standard duration for this sodium carbonate method is typically 30 to 60 minutes [7]. The exact time can vary depending on the desired level of degumming and the type of silk.
- Washing: After the boiling treatment, the silk is thoroughly washed with water [7]. This step removes the dissolved sericin and residual chemicals.
This process effectively removes the sericin, leaving behind the pure fibroin fiber, which is significantly softer, whiter, and has a higher luster.
Summary of the Most Common Method:
- Chemical: 0.02 M Sodium Carbonate (Na2CO3) buffer
- Temperature: Boiling
- Time: 30 to 60 minutes
- Follow-up: Washing with water
This chemical and thermal treatment is effective because sodium carbonate is alkaline, which helps to hydrolyze and solubilize the sericin protein.
