How to bleach silk

The degummed silk fibers should be bleached to remove natural pigments. Otherwise, when dyeing light colors, the color of the finished product will change due to the presence of natural pigments. Silk can be bleached by oxidation or reduction of various bleaching agents. There have been reports on the process of bleaching silk with hydrogen peroxide in the presence of a catalyst. Thiourea dioxide is a reductive bleaching agent with low BOD and COD values, so it can be used as a low-pollution non-toxic bleaching agent. However, compared with the sodium sulfide, although it is heavily polluted, it is still used in large quantities. However, the application of TDU is limited due to its high price.