Complexing agents in raw wool scouring

Most of the foreign matter present in raw wool is removed during wool scouring but residual impurities always remain on the fibre material. The impurities affect the colour of wool, which in turn influences its price, and can also cause problems during processing. In this work, the effectiveness of complexing agents is studied in raw wool scouring and in scouring experiments with wool tops treated with FeCl3 solutions. Complexing agents assist soil removal in raw wool scouring and improve the whiteness and cleanliness of wool. The best effects were obtained in scouring very dirty wool with complexing agents based on alkyl phosphonates. Alkyl polyphosphonates, polyacrylates with saccharide side groups, carboxylic acids and polyacrylates were found to be the most effective in removing iron ions from wool under raw wool scouring conditions, resulting in an improved whiteness. Recently developed, mild, ecofriendly complexing agents, such as iminodisuccinic acid and polyaspartic acid, are only slightly effective in removing iron ions from wool under scouring conditions.