The effects of residual surfactants on the dyeing of wool

Wool fabric was extracted with various organic solvents at their boiling points and then dyed with Coomassie Blue BL200. Non–dyed areas of fabric were observed after extraction with ethanol, acetone/ water (70:30) and chloroform/methanol (70:30) mixtures, but not after extraction with perchloroethylene. Silica column chromatography separated the extracts from various solvent pretreatments into five major peaks, based on mass obtained. Some of these peaks were shown to contain cholesterol, non–ionic surfactant and phospholipid. Up to 14 components were detected by two–dimensional thin layer chromatography of the extracts. Thin layer chromatography revealed that some of the more polar components were not extracted by perchloroethylene. Separation of the extracts by column chromatography enabled a study of dye uptake to be carried out after recontamination of pretreated fabric with the major fractions. Materials in two of these fractions were found to eliminate the uneven dyeing observed with Coomassie Blue BL200. Column chromatography and spot tests showed that they behaved similarly to the non–ionic surfactant Antarox CO 630. These experiments also showed that refluxing perchloroethylene extracted only about half as much non–ionic surfactant as did refluxing chloroform/methanol (70:30) mixture. The residual surfactant may originate from the scouring process and/or from processing oils such as Mulrex.