Effect of different filters on the extraction of norbixin from Bixa orellana for synthetic fiber dyeing and development of a post-dyeing process for removal of the unfixed dye

The aim of this study was to compare the efficiency of three types of filters for the extraction of the annatto dye from Bixa orellana for polyester dyeing. In addition, post-dyeing washing processes were proposed to improve the wash and rubbing fastness. In the extraction procedure the paper filter presented the highest yield (13.3%), followed by the polypropylene (11.4%), but there was no significant difference in the results for the exhaustion percentage (average of 87.4%) and K/S values (1.68 to 2.24). Results showed the polypropylene filter was the most suitable and can be reused. The post-dyeing washing processes with detergent improved the fastness increasing the color transfer score from 1.5 (large change) to 3 (small change). An acceptable color difference between the dyed fabric samples before and after washing was observed. Results indicate that the post-dyeing washing process improves the quality of dyed fabrics to levels acceptable for industrial application.