Green coffee powder is the raw powder of coffee cherries and all coffee's potential components are held within this green powder. A new natural colourant was extracted from Green Coffee using water as an extractant. To obtain a green-colored solution, a specific amount of green coffee was mixed with distilled water and left for 24 h at room temperature. Furthermore, the colouring performance of extracted colour has been studied using the conventional exhaust dyeing method on wool fabric. Different parameters viz. concentration of Green coffee powder, the temperature of the dye bath, the period for immersion, and solution pH were made to set to obtain a fine tone of green colour. The dyeing parameters (amount of the coffee: 2 g, 100 °C, 70 min & 6.7 pH) were optimised and selected to draw a comparison with the conventional Brown coffee powder. In experiments on wool, this potential solution of Green coffee offered rich green hues with good tonal variation. In addition, the colour fastness to washing was found superior in the case of both Green and Brown coffee and colour fastness to light, rubbing as well as perspiration also showed good performance. In this study, our main focus was to obtain the true and fast green tone of the fabric using Green Coffee and compare it with brown coffee using the same conditions used for dyeing with green coffee. The application of these dyes as natural dyes results in obtaining innovative natural fast colour with remarkable dyeing properties and a new inclusion to the existing commercial spectra of natural dyes.
Keywords: Brown coffee; chlorogenic acid (CGA); fastness properties; green coffee; wool.