The Research On The Extraction Of Lawsonia Inermis Pigment And Dyeing To Protein Fibre

As a kind of natural plants, Lawsonia Inermis has complex chemical composition and strong physiological activity. Due to its natural and harmless characters, it is used as a raw material of the natural harmless hair dyes and textile. The medical value of the Lawsonia inermis is very high. In addition, it has anti-corrosion effect. Its development and utilization have wide prospects.Comparison of the distilled water, ethanol, petroleum ether etc., the result indicated that distilled water was the optimum solvent for the extraction of Lawsonia inermis pigment. The effects of the temperature, time, material ratio were discussed, and the optimum extraction method was demonstrated as: at 60 C, material ratio was 1:8, extraction one hour, and extraction 3 times.The physical and chemical properties of the Lawsonia inermis pigment were studied. The results showed that the pigment is soluble in the water. The heat resistance was better than common natural pigments. The light had influence upon the stability of the pigment, so we should avoid light when the stored for long time. The bathochromic shift in the absorption spectrum of the pigment was found as the pH was raised. Some common metal ion had different effect on the pigment; the effect of iron was most obvious. To some degree, the pigment can endure reduction, but the ability of oxidation resistance was weak.Through orthogonal experiments, the dyeing of Lawsonia inermis pigment to silk was explored, and the key factors were discussed. The fastnesses dyed with different process were compared. The result proved that the acid condition facilitated dyeing. The concentration of dye was the most import influence factor. The concentration higher, the surface color of the fabric darker. The samples, nomatter were direct dyed or mordant dyed, had very good color fastness to friction. Color fastness to washing and to acid sweats steep were over 3 grade, but the color fastness to alkaline steep was poor.The best dyeing conditions were studied and gave as : the concentration of Lawsonia inermis pigment was 5%, pH of the dye bath was 4, the temperature of dyeing was 60C and the time of dyeing was 60 minutes. The fastness of dyed sample was tested, the result showed that Color fastness to washing and to acid sweats steep were 3-4 grade, but the color fastness to alkaline steep was poorer, only reached 2 grade.