Extraction Of Natural Dyes And Dyeing Of Protein Fibers

Microwave extraction was used to extract rhubarb and madder, the effects of solvent volume fraction, extraction time, temperature and power on extraction efficiency were investigated by measuring the K/S value of the wool after dyeing and the extraction process was optimized. In addition, the silk fabric was dyed with natural dyes rhubarb and madder. The effects of dyeing dosage, dyeing time, temperature and pH value on dyeing efficiency were studied, and the optimum dyeing process was determined. The color performance of four kinds of natural dyes were studied.The dyed wool fiber was treated with formaldehyde-free dye-fixing agent, and the change of K/S value and color fastness of wool fiber after fixation was studied. The content of anthraquinones in rhubarb extract was studied by HPLC. The results are as follows:The optimum extraction conditions of rhubarb and madder were as follows: Ethanol volume fraction40 %, extraction time 6min, extraction temperature 90 ?, extraction power 450 W. Ethanol volume fraction 60 %, extraction time 5 min, extraction temperature 90 ?, extraction power 400 W.The dyeing process of silk fabric by rhubarb and madder were as follows: Dyeing time 65 min,dyeing temperature 90 ?, pH value of 4. Dyeing time 30 min, dyeing temperature 95 ?, pH value of 4.Four natural dyes can be mixed with each other dyeing.Fixing agent 1: The wet rubbing fastness of rhubarb dyed wool can be increased to 4 ~ 5; the cotton stain fastness of dyed wool by madder was increased by one grade; the color fastness of dyed wool by cetraria islandica is not changed too much; the cotton and wool stained fastness and fading fastness of dyed wool by modified indigo can be increased by one grade.Fixing agent 2: The fastness of dry rubbing of rhubarb dyed wool was improved by one grade. The color fastness of dyed wool by madder or cetraria islandica was not much changed. The wet rubbingfastness and wool stained fastness and fading fastness of dyed wool by modified indigo can be increased by one grade.Rhubarb solid dye contained 1.31 % emodin, 0.86 % chrysophanol, 0.25 % physcion, 0.06 %aloe-emodin, 0.02 % rhein.