Oral
Abstract
Research summary supplied by the authors
Dyeing levelness on vegetable re-tanned leather is often affected by the presence of iron. Although adding vegetable tannins is very cost-effective for increasing the fullness of the leather, the polyphenolic compound of vegetable tannins can react with excess ferrous ions from ion-complexed dyes and form black complexes and precipitates on leather. Herein, we present a quantitative measurement of dyeing levelness in a series of vegetable tannins and ferrous ions concentrations. Then we provide a practical solution for lowering the formation of black complexes and hence improving the dyeing levelness of leather.