Alkaline dissolution and dyeing properties of sea-island type polyethylene terephthalate ultramicrofiber knitted fabrics

Sea-island type polyethylene terephthalate ultramicrofibers with a single fiber diameter of ca. 600 and 800 nm have been produced over the last 4 years. Alkaline dissolution behavior and dyeing properties of the ultramicrofiber fabrics were investigated. It was found that the dissolution ratio was dependent upon temperature in the alkali treatment. When the fabric was treated with 1 wt% sodium hydroxide solution at 95 °C, the dissolution ratio reached the theoretical value in about 30 min. Alkali dissolution behavior could be monitored indirectly by the cationic dye staining method and observed directly by SEM analysis. The color yield of the ultramicrofiber fabric dyed with disperse dye was dependent on the dyeing temperature and K/S value decreased as the dyeing temperature increased. Build-up property was generally good and K/S value of dyed fabric from ca. 800 nm fiber was higher than that from ca. 600 nm fiber. Wash fastness was poor to moderate for ca. 800 nm fabric and poor for ca. 600 nm fabric. Light fastness was very poor.