Improvement of dye affinity in natural dyeing usingTerminalia chebula retzius(T. chebula) applied to leather

Purpose The purpose of this paper is to improve the dye affinity of natural dye of Terminalia chebula retzius ( T. chebula ) using the dye substrate of leather. Design/methodology/approach The dyeing conditions such as temperature, concentration of dye, and time are controlled by measuring the dye affinity. The effect of enzymatic post-tanning process on dye affinity is evaluated by using different type of proteases such as flavourzyme, alcalase, and bromelain. The optimum conditions for enzymatic post-tanning process are evaluated depending on different pH, temperature, and concentration of enzyme. Findings The highest dye affinity was obtained at 50°C using a dye concentration of 200 percent (owf) for 30 min treatment by measuring of K/S values of dyed leather. Distilled water was proved as a better extraction liquid to improve the dye affinity of T. chebula . The K/S values of dyed leather were enhanced after the enzymatic post-tanning process by flavourzyme. Moreover, the fastness properties against the rubbing and dry cleaning of the dyed leather were improved by the enzymatic post-tanning process. Originality/value In this paper, the enzymatic post-tanning process is introduced as the method to improve the dye affinity in natural dyeing using Terminalia chebula retzius ( T. chebula ) applied to leather. The results of the study could be applied for further natural dyeing of leather using various natural dyes.