Comparative Study on the Effects of Laser Bleaching and Conventional Bleaching on the Physical Properties of Indigo Kapok/Cotton Denim Fabrics

Danying Zuo,Houlei Gan,Changhai Yi,Wei Du

doi:10.3390/app9214662

Abstract

Kapok is a hollow fiber with a 90% hollow degree. Compared with cotton fiber, kapok fiber has excellent performances, such as good hygroscopicity, and a good warmth retention property. In this work, desized indigo kapok/cotton denim fabrics were bleached in different ways: Laser, cellulose enzyme, sodium hypochlorite, potassium permanganate and hydrogen peroxide. After bleaching, the K/S values, tensile strength, air permeability, thickness, color fastness to rubbing and the crease recovery angle of denim fabrics were measured through the spectrophotometer, tensile strength tester, air permeability tester, thickness tester, rubbing fastness tester and fabric crease elasticity tester, respectively. The surfaces of fabrics and fibers were observed by scanning electron microscopy (SEM). Results show that the kapok/cotton fabrics were color-faded after five kinds of bleaching, the K/S values of denim with laser bleaching was declined dramatically, while there was a little change in the permeability. The tensile strength and the weight of the fabrics were decreased, and cloth which was bleached with potassium permanganate was most affected. The color fastness to rubbing and the crease recovery angle of denim fabrics with laser treatment is most suitable for industrial production. In general, laser bleaching is the better way to fade the kapok/cotton denim fabrics. Meanwhile, after five kinds of bleaching, the physical properties of kapok/cotton denim fabrics were similar to those of cotton denim fabric, which indicates that kapok/cotton denim fabric is suitable for the existing industrial bleaching technology.

Highlights

Denim is a rugged cotton twill fabric with weft yarns passing under two or more warp threads.In the history of the world, the continued popularity of blue jeans among consumers is well documented, which makes indigo one of the most important industrial dyes
The K/S value indicates the degree of dyeing of the fabric
It is a fact that after laser or potassium permanganate treatment, the K/S values decrease dramatically. This shares a similar trend with the cellulose enzyme treatment, sodium hypochlorite treatment and hydrogen peroxide treatment on K/S values loss

Summary

Introduction

Denim is a rugged cotton twill fabric with weft yarns passing under two or more warp threads. In the history of the world, the continued popularity of blue jeans among consumers is well documented, which makes indigo one of the most important industrial dyes. Indigo undergoes complex heterogeneous processes that occur at the solid–liquid interface. The indigo dissolution process involves the conversion of water insoluble dye molecules to water soluble, colorless forms by reduction [1,2]. Indigo denim fabric is characterized by only warp dyeing and the weft remains white. The result of a warp-faced twill is a blue warp on one side and a white weft on the other [3]

Methods

Results

Conclusion