抄録
As the basic study to investigate the mechanism of improvement in the dyeing fastness of natural dyes on silk fabrics, the optical behavior of tannin solution, the optimal condition of tannin treatment and the changes of the physical structure of silk fabrics were studied in the treatment of tannin. As the tannin content of silk fabric was increased, the value of ξ-potential became negative. As the tannin content of silk fabric was increased, the crystallinity and crystallite size were decreased. The degree of orientation was also decreased with the tannin treatment. As the concentration of tannin was increased in its treating condition, the tannin content and K/S value of tannin-treated silk fabrics were increased. Because tannin gave rise to yellowing by hydrolysis and oxidation at high temperature, the higher tannin-treating temperature resulted in the lower the tannin content and K/S values of silk fabrics. The tannin content of silk fabric was higher in acidic treating condition and the highest K/S value was showed at pH 5. The optimum condition of tannin pre-treatment was 0.15% concentration, pH 4, 70°C, and 45min, and that of post-treatment was 0.05% concentration, 60°C, and 30min. The wash fastness and the light fastness were enhanced to 4 grades and 2~3 grades, respectively.
