Dyeing of polyamide / elastane fabric with natural indigo dye and application for producing women’s intimate apparel

Abstract

The purpose of this research was to study the dyeing polyamide/elastane fabric with natural indigo, using exhaustion dyeing process. The effects from the concentration of the natural indigo dye, thiourea dioxide and sodium hydroxide were investigated. The colour of each dyed material was investigated in term of the CIELAB (L*, a* and b*) and K/S value. The color fastness to washing, rubbing, perspirdation, light, water, sea water and chlorinated water of the dyed samples was determined. The bursting strengrh of dyed polyamide/elastane was evaluated. The best vatting condition was at 50 ̊C for 30 minutes. The optimal formula of dyeing polyamide/elastane fabric using natural indigo was prepared by mixing 200 g/L natural indigo paste, 60 g/L thiourea dioxide, 1 g/L sodium hydroxide. The fabric dyed in the solution of indigo vatting a shade of dark blue colour. The color fastness to light, washing, water, sea water, perspiration and chlorinated water were good to very good. However, the rubbing fastness results showed fair level. The bursting strength of dyed fabrics is less than the undyed fabric 3.1%. The optimal ratio of discharge printing on polyamide/elastane fabric were compose of 70 % starch print paste and 30 % discharging agent (KMnO4). The pattern design produced from these combinations in the printing areas on fabrics showed an excellent standard of printing quality. The results confirmed that natural indigo dyes have potential applications in polyamide/elastane fabric dyeing and the dyed fabric can be used produce women’s intimate apparel.