Study On The Printing Technology Of Silk Fabric With Natural Dyes

Natural dyes, are abtained from nature, having the virtue of non-toxic, biodegradable, environment friendless, and especially some natural dyes have the properties of anti-uv and antibacterial, the silk fabric printed with natural dyes can get a harmonious and multifarious health-care function which meet the demands of health and environmental protection, therefore it is great significant to research the natural dyes printing.This paper is focused on the research about the effect of different mordants on PVI value, viscosity and storage stability of the paste, and selection of the paste which are not only compatibile with mordant, but also have good permeability and high colour yield for printing; In order to screen the dyes which have high color depth and good fastness for printing to improve the fastness of printed fabric, dyeing performance of 10 kinds of natural dyes are analyzed; the printing methods of different dyes are analyzed; in order to get the optimal printing process conditions, the effect of mordant and mordant dosage, steaming temperature and time on the K/S value of the printed fabric are analyzed; finally the preparation of natural dye complexes are studied, and the natural dye complexes are applied in silk printing.The results show that WD-17 paste has higher stability after adding metal salt, the fabric printed by WD-17 paste has high colour yield and good penetration rate, so it can be applied in natural dyes printing; the screened six kinds of natural dyes are used in silk fabric printing, the optimal printing methods and optimal printing technology parameters are as follows, the method of lac is pre-mordant printing, the mordant(alum,ferrous sulfate,rare earth) dosage is 5-7%(o.w.f), the steam temperature is 110℃, and the steam time is 20min; the method of sappanwood is meta-mordant printing, the mordant(alum,ferrous sulfate,rare earth) dosage is 6-7%, the steam temperature is 110℃, and the steam time is 30min; the method of SBG is meta-mordant printing, the mordant(ferrous sulfate,rare earth) dosage is 6-7%, the alum dosage is 7-8%, the steam temperature is 110℃, and the steam time is 30min; the method of mulberry is post-mordant printing, the mordant(alum,ferrous sulfate,rare earth) dosage is 7-8%(o.w.f), the steam temperature is 110℃, and the steam time is 20min; gardenia yellow, gardenia blue adopt direct printing, the steam temperature is 110℃, and the steam time is 20min;The optimal process conditions of baicalin-Al(Ⅲ) complex for synthesis are as follows, mole ratio of baicalin / alum is 2:1, pH value is 5~6, temperature is 30℃, and time is 30min; the optimal process conditions of baicalin-Fe(Ⅱ) complex for synthesis are as follows, mole ratio of baicalin / ferrous sulfate is 2:1, pH value is 6~7, temperature is 50℃, and time is 20min; the optimal process conditions of lac-Al(Ⅲ) complex for synthesis are as follows, mole ratio of lac / alum is 2:1, pH value is5~6,temperature is 70℃, and time is 2 hour; FTIR results show that 5-phenolic hydroxyl group and 4-carbonyl group of baicalin are involved in the complex reaction; UV spectrum shows that after the natural dyes react with metal salt, the absorption peaks are redshifted in varying degrees; the preparaed natural dye complexes are used in silk printing, the fabric printed by natural dyes complex can not only gain higher K/S value and good fastness but also shortened the printing process, and reduced water pollution caused by metal salt.