Reduction of indigo backstaining by post-washing

• Autor(a) principal: Andreaus, Juergen
• Data de Publicação: 2001
• Outros Autores: Campos, Raquel de, Paulo, Artur Cavaco
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/1822/12729

The undesired redeposition of indigo during the enzymatic ageing of denim garments with cellulases is a problem widely known in industrial laundries. Today, the usual procedure carried out to reduce the undesired side-effect is post-washing, but so far little information can be found in literature about efficient methods to achieve a maximum blue-white contrast in denim garments. This article deals with the possibilities of removing physically adsorbed indigo from cotton fabrics and of reducing the undesired effect of indigo backstaining in a post-washing step. Different chemical reaqents and textile auxiliaries were tested and compared, Up to 80% of the initial colour could be easily removed with one-component washing-solutions and under conditions of high mechanical agitation. Ethoxylated linear fat alcohols and a modified poly acrylic acid were found to be the most efficient chemical reagents at low concentrations to desorb indigo from cotton. Non-ionic surtactants desorbed more indigo-with a decreasing degree of ethoxytation. With non-ionic surfactants the desorption at indigo improved with a decreasing degree of ethoxylation. The best results were achieved with a complex standard detergent