Development of Ecological Denim Bleaching Methods

Abstract

Although the textile industry has many products to offer to humanity, it consumes a lot of energy and indirectly causes greenhouse gas emissions. With increasing environmental awareness, parameters such as the cost and performance of each industrial activity to society, as well as the use of natural resources and the possibility of causing global environmental problems to have become more frequently considered factors. In the denim bleaching process, the desired effect is usually obtained with the help of sodium hypochlorite. Sodium metabisulfite is then used for the neutralization process. Since these processes are carried out at high liquor ratios, the waste load resulting from the consumption of necessary chemicals and water is also high. In this study, ecological bleaching methods have been developed as an alternative to the conventional sodium hypochlorite bleaching method by reducing the use of water and chemicals with low liquor and spraying bleaching methods. Denim garments subjected to bleaching with low liquor and spraying methods were compared with denim garments applied to sodium hypochlorite bleaching in industrial washing machines according to exhaustion method. In the spraying method, the mixture coming out of the narrow nozzle is mixed with the compressed air by means of a specially designed spray gun and sprayed in very small droplets. Thus, a good atomization is ensured, and a low liquor ratio water cloud is created.