Combined Bleaching, Shrinkage Prevention, and Biopolishing of Wool Fabrics

Abstract

In earlier work, we established that alkaline hydrogen peroxide systems that include dicyandiamide, gluconic acid, and Triton X surfactant, used alone or followed by enzyme treatments, control shrinkage in wool fabrics to 3.0% and 1.2%, respectively. We have perfected this system for complete shrinkage control with no loss in mechanical properties by using the same pretreatment and enzyme applied from a buffered triethanolamine solution that incorporates sodium sulfite. Fabrics treated by this method are bright white and exhibit a soft handle with a smoothed surface. Digital image analysis is used to quantify fiber projections above the fabric surface for a measurement of smoothness. A statistical analysis with a central composite design reveals the optimum concentrations of enzyme, sodium sulfite, and exposure time that maximize shrinkage control while maintaining adequate levels of tensile strength and weight loss.