The Study on Cotton Fabric Dyeing by Indigo Blue from Baphicacanthus Cusia, Indigofera Tinctoria and Polygonum Tinctorium

Abstract

In this study, 750 g of Taiwan plant-baphicacanthus cusia, indigofera tinctoria and polygonum tinctorium, with two reducing agents-60 g sodium hydrosulfite and 12 g thiourea dioxide were added to dye the cotton fabric for 60-90 seconds, 1-15 times repeatedly. After this, take the cloth specimen being dyed for 3 minutes with the 15th times to compare with the original cloth for color difference (dE). According to the experiment, with the addition of sodium hydrosulfite, dE value of the baphicacanthus cusia, indigofera tinctoria and polygonum tinctorium specimen was 71.70, 69.57 and 70.91 respectively, while with the addition of thiourea dioxide, the dE value of baphicacanthus cusia, indigofera tinctoria and polygonum tinctorium specimen was 73.43, 68.91 and 65.86 respectively. As for washing fastness test, when indigofera tinctoria was reduced with sodium hydrosulfite, the washing fastness test was rated as grade 3-4. For other specimens, they were just grade 3. In the softness test, when the sodium hydrosulfite was added to indigofera tinctoria, the lowest flexural degree was 5.6 cm. In the ultraviolet resistance test, the sodium hydrosulfite with polygonum tinctorium showed the best result with T% 0.19. The dyed cotton fabric also revealed the characteristic functional peak of indigo blue at 1624 cm-1 via FT-IR test.