Colorfastness Properties of Dyed, Reduction Cleared, and Softened Poly(lactic acid) Fabrics

Soft eners are usually applied to fabrics, including those made from polylactic acid, to improve hand and to reduce friction between fi ber/fi ber and fi ber/metal during production. Commercially available soft eners of diff erent hydrophilicity, ionicity, and chemical type were applied to poly(lactic acid) fabric that was dyed to a heavy depth of shade with C.I. Disperse Blue 284 to evaluate the eff ect on wetfastness and lightfastness. Finishing with all soft eners reduced wetfastness but not lightfastness properties; little correlation was found with soft ener chemistry. In general, wetfastness and lightfastness of soft ened poly(lactic acid) fabrics were lower than that of soft ened poly(ethylene terephthalate) fabrics. Th e reduction in wetfastness, and particularly crockfastness, of poly(lactic acid) fabric was less marked if the soft ener was applied by an exhaustion process rather than by a padding process. Key Terms: Colorfastness, Finishing, PET, PLA, Poly(lactic acid), Soft ener