Over dyeing of tussah silk with indigo naturalis and turmeric

To enrich the variety of color of natural dyes and make up for the lack of green spectrum in natural dyeing process,two kinds of vegetable dyes including indigo naturalis and turmeric were selected to over dye tussah silk fabric.The effects of dyeing concentration,pH value,temperature and time on the K/S value,antibacterial property,levelness,and color fastness were investigated,along with dyeing mechanism.The results indicated that a series of green spectrum could be obtained by over dyeing the tussah silk which had been dyed with turmeric dye.The dosage of turmeric dye liquor had the greatest effect on the K/S value of the dyed tussah silk.It was found through orthogonal experiment that the optimum dyeing process was as follows: dosage of turmeric dye liquor 30%,dyeing at 80 ℃ for 60 min at pH=4.The rubbing fastness and washing fastness of the dyed tussah silk were all above grade 3,and the bacterial inhibition rate against S.aureus and E.coli reached 92.56% and 80.41%,respectively.