Relaxation of knitted fabric by low pressure evaporation

By applying micro-agitation to plain knit fabrics, the fabric can be effectively relaxed. Water evaporates when pressure drops. When a piece of wet fabric is subjected to a rapid drop in pressure, the water in the fabric will evaporate rapidly. The pressure field created upon rapid evaporation provides the micro-agitation operating in close vicinity of the fibres in the fabric. A chamber was built to provide a suitable environment and a new LPR (Low Pressure Relaxation) process was developed. Experiments were performed with two sets of fabrics, one from cotton and the other from wool. Results were compared between the new LPR process and wash and tumble drying process. Comparable dimensional change upon the two relaxation processes confirmed that the new LPR process is able to relax knitted fabrics effectively.