Comparative study on the effects of laser bleaching and conventional bleaching on the physical properties of indigo kapok/cotton denim fabrics

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 technolog