Effective Lac Dyeing of Cotton Fabric by Pretreating with Tannic Acid and Aluminum Acetate

Lac dyeing of cotton fabrics pretreated with tannic acid and aluminum acetate was investigated. Five treatment methods (tannic acid alone, aluminum alone, tannic acid -> aluminum, aluminum -> tannic acid, and tannic acid luminum ->tannic acid) before dyeing with lac were compared for their effect on adsorption of the laccaic acid to cotton fabric. The treatment with tannic acid -> aluminum was found to be the most effective for lac dyeing of cotton. It was found that tannic acid enhanced the aluminum adsorption to cotton fabric, and the affinity of aluminum to laccaic acid enhanced the dyeing effect. The adsorption of tannic acid, aluminum and laccaic acid to cotton was quantitatively determined, and the dyeing mechanism was proposed.