Fabrication of nontoxic natural dye from sappan wood

The use of natural dyes has attracted increasing worldwide attention as the carcinogenicity and environmental pollution problem of synthetic pigments are becomes a great concern. A nontoxic natural dye was fabricated from an extract from Caesalpinia Sappan (sappan wood). Oily natural dye for industrial application was made from extracted sappan wood by using a micro-emulsion method. The absorbance of the dye extracted from sappan wood by distillation was measured with an Ultraviolet/Visible spectrometer. The highest absorbance was obtained from the mordant containing 2 wt% Al. The emulsification conditions were controlled by changing the mixing ratios of TEOS (tetraethyl ortho-silicate), DC3225C (cyclomethicone and dimethicon copolyol) and extracted dye. A W/O (water in oil) type dye was obtained with a TEOS concentration ranging from 19.9 to 50.0 wt% when the DC3225C concentration was fixed to 10 wt%. The W/O type emulsion was verified by optical microscopy. The fabricated dye was applied to colored paper. The applicability of the nontoxic natural dye was verified by analyzing the heavy metals and color fastness of the colored paper.