Study On Dyeing Silk Fabric With The Vat Dye At A Lower Temperature

There are two kinds of property of silk. Weak acid dyes, direct dyes, neutral dyes, reactive dyes are used to dye silk. The disadvantage of these dyes is the lower insolation fastness. Vat dyes are a class of fine traditional dyes, with the advantage of complete chromatography, bright colors, good fastness, especially excellent light fastness. The possibility of dyeing silk fabric with the vat dyes are discussed, under the premise of no affecting to the property of silk fabric.Silk fabric is dyed with vat dyes under alkaline conditions, but the silk fiber is not able to bear alkaline, so the silk fiber will be damaged under the effect of high temperature and alkali conditions. In order to protect the silk fiber effectively, the experimental mainly study the influence to silk fabric strength and K/S such as choice of dye, alkali agent type, pH,silk protectants , dyeing temperature and dyeing time. At last, dyeing process of silk with vat dyes is determined.The particle size of vat dyes, before and after grinding, are measured by laser particle size analyzer. The leuco dyes aggregation behavior is discussed. The results show that the dye particles can be ground finer. The reaction interface of vat dyes, sodium hydrosulfite and the alkaline agent is increased because of finer vat dyes particle, and less sodium hydrosulfite and less alkaline agent will be needed. It will reduce the silk fabric strength damage inevitably.As the silk dyed by vat dyes at lower temperature, the low K/S will be obtained. The high K/S can be obtained by oxidizing the vat leuco dyes several times.The optimal dyeing process of silk with vat dyes is determined. The silk fabric, dyed under the optimal dyeing process ,is surveyed about the property, such as capillary effect, crystallinity, amino acids content, fiber Surface surveyed by SEM, fabric Style, dyeing fastness. The results show that original features of silk are reserved, and good fastness is obtained.