Optimization of discharge printing of indigo denim using potassium permanganate via response surface regression

Abstract

PurposeThis paper aims to investigate the feasibility of potassium permanganate (KMnO4) as an efficient discharging agent for indigo-dyed denim fabrics and identification of key variables for its cost-efficient implication.Design/methodology/approachResponse surface methodology, which is a statistical technique for the optimization of process variables, was used to study the effect of three key variables, i.e. KMnO4 concentration, printing paste pH and reaction time on whiteness and strength of discharged printed fabric. Regression models were developed to predict response variables, i.e whiteness, tensile strength and tear strength of discharge printed denim.FindingsIt was found that some captivating discharge printing effects could be produced using appropriate KMnO4 concentration, printing paste pH and reaction time without any significant loss in the fabric strength.Practical implicationsThis study highlights the practical implication of KMnO4 to be used as a safe and effective discharging agent under different conditions and to optimize the parameters using statistical analysis to ensure minimum loss in textile properties. The use of denim has evolved over the decades from a rough and tough workwear to highly fashionable apparel. Various dry and wet processing techniques have been introduced in recent years for the value-addition of denim – discharge printing is one of them. As lab to bulk reproducibility requires some sort of experience and adjustments in main parameters, the practical feasibility on the bulk scale should be adjusted in advance by means of the lab scale experimentation.Originality/valueThe KMnO4 oxidation process is considered eco-friendly because manganese dioxide, which is formed when permanganate is reduced, can be recycled. Thus, the use of KMnO4 can be considered as an eco-friendly safe process for the discharging of indigo dyes.