Bleachability and Dyeing Properties of Biopretreated and Conventionally Scoured Cotton Fabrics

Abstract

Enzymatic (cellulase, pectinase, xylanase) and simple buffer treatments in the presence of a nonionic surfactant improve water wettability of fabrics to a level equal to conventional alkaline scouring. Caustic scoured fabric is significantly lighter and less colored than all the biopretreated samples. Application of a hydrogen peroxide bleaching subsequent to the biopretreatment is beneficial because it reduces the great color differences between conventionally scoured and biopretreated samples. Bleachability of the pretreated fabrics is better than that of the conventionally scoured sample. Biopretreated fabrics can be dyed with a reactive dye subsequent to the enzymatic treatment without further oxidative bleaching. At higher dye concentrations ( i.e., 1 or 2%), there is no perceptible color difference between the biopretreated and alkaline scoured fabrics in the dyed state. In pale and medium dyeings, however, the color difference is great and perceptible. Bleaching applied subsequent to bioscouring significantly decreases the color difference between the dyed samples pretreated in different ways. None of the pretreatments causes uneven dyeing. Wash fastness of the dyed samples is excellent and unrelated to the pretreatment method.Preparation and bleaching are among the most energyand chemical-intensive steps in traditional cotton finish-

A facile energy and water-conserving process for cotton dyeing

“…These are processes in which individual stages of treatment, viz., acid demineralisation, alkaline scouring, hydrogen peroxide bleaching and the elimination of residual peroxide with subsequent reactive dyeing occur without the normal intermediate washings. Losonczi et al [13] studied the conventional and bio-preparation scouring processes of cotton fabrics and also studied the bleaching and dyeing with reactive dyes of such pre-treated fabrics. Kokol and Golob [14] performed biopreparation of raw cotton using enzymes and also carried out reactive dyeing in the same bath.…”

Advances in Denim Research

“…In the wet processing of denim different mechanical and chemical operations of finishing can be replaced by enzyme treatments, as enzymes are eco-friendly, non toxic, and fully biodegradable compounds. Enzyme technology besides other advantages, also enables process integration [4][5][6][7]. The main advantages of enzymes used in denim finishing are efficiency, accelerated reactions, being operational under mild conditions, acting on a specific substrate exclusively, easiness of control, biodegradability, and a wide range of industrial applications.…”

A Pilot-Scale Application of Ozone to Bleach Raw Cotton Fabric Using Various Additives

“…The conventional bleaching method is energy intensive and costly due to the substantial application of chemicals and high temperatures, followed by intensive washing of the substrate to sweep away any residual hydrogen peroxide which is a pre-requisite for quality dyeing, as dyes are repulsive to the oxidizing agents (El Shafie et al 2009, Hebeish et al 2009Losonczi et al 2004). Resultantly, conventional bleaching generates massive amount of highly polluted wastewater which requires treatment in compliance with strict environmental laws before its disposal into water bodies (Fakin et al 2008;Senthilkumar and Muthukumar 2007;Sevimli and Sarikaya 2002;Sundrarajan et al 2007).…”