Abstract
The Purpose of this studs was to investigate dyeing properties of silk and nylon fabrics by Polygonum cuspidatum extract. The properties were evaluated by it's extracting condition, dyeing condition, mordants variables, methods of mordanting and color fastness. Silk fabric showed the highest K/S value at $50-70^\circ{C}$, while Nylon fabric showed at $90^\circ{C}$. Surface color of dyed fabrics were various by the used mordants ; none-, and Al-mordanted fabrics were yellow, Cu-mordanted fabrics were redish yellow, Fe-mordanted fabrics were olive green. Fe-mordanted silk fabrics showed excellent laundering fastness and light fastness. Both silk and nylon fabric showed excellent laundering and dry cleaning fastness.