Extraction, characterization and application of annatto dye in the dyeing of natural fibres

摘要

Dyes extracted from annatto (Bixa Orellana L) seeds are being used in this study. The plant is from tropical region and represents 70% of all the natural dyes produced in the world and 90% in Brazil. The present work describes the method used for extraction of the dyes from the seeds and it's characterization. Also the method of KOH was used to determine the bixin content of the extracted dye. Ethyl alcohol was used as the extracting agent as well as the facility to recover it through distillation and reuse of the same thus, keeping the costs minimum. The extracted dye was in the form of powder and the concentration was seven times stronger than bixin (main dye component) with 4 times in quantity in comparison to other available methods. The dye was then used to dye cellulosic fiber by exhaustion method. Dyeing was carried out using mordents through pre and post mordent dyeing in order to compare the fastness properties of the dye. Reflectance curves of the dyed materials were made using Gretag McBeth Colour Eye 7000A spectrophotometer.