Process of dye-free coloration of tussah silk based on hydroxybenzaldehyde

Tussah silk fabric was treated with p-hydroxybenzaldehyde and nitric acid in order to achieve the purpose of dye-free coloration.Through orthogonal experiments and single factor analysis,the optimum process of dye-free coloration was,p-hydroxybenzaldehyde 5%(o.w.f),nitric acid 2.5%,temperature 90 ℃,time 60 min and bath ratio 1∶30.Meanwhile,the color fastness,evenness,strength,and morphology of colored fabric were tested.The results showed that the tussah silk fabric after dye-free coloration displayed bright shade,good evenness,little fiber surface damage and loss in breaking strength,with both rubbing fastness and washing fastness rating of above 4.